JP2016004131A - Lubricant supply quantity control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricant supply quantity control device capable of supplying a lubricant of a proper amount on the surface of an image carrier.SOLUTION: A lubricant supply quantity control device controls a supply quantity of a lubricant by a lubricant supply part for supplying the lubricant on the surface of an image carrier for electrostatically carrying a developer image constituted of a charged developer, and includes: a transfer rate estimation part for estimating a rate of amount of the developer transferred from the image carrier when transferring the developer image by electrostatically moving the developer constituting the developer image carried on the image carrier from among the developers constituting the developer images carried on the image carrier; and a lubricant supply amount control part for controlling a supply amount of the lubricant per unit time to the surface of the image carrier by the lubricant supply part.

Description

  The present invention relates to a lubricant supply amount control device, and more particularly to application of a lubricant to the surface of an image carrier.

  2. Description of the Related Art In recent years, image forming apparatuses such as printers used for outputting computerized information, facsimiles, and copying machines used for document copying have become indispensable devices. Among such image forming apparatuses, an image forming apparatus using an electrophotographic method is known.

  When forming an image on transfer paper, an electrophotographic image forming apparatus first forms an electrostatic latent image by charging the surface of a photoconductive drum, which is an image carrier, with laser light, and develops the color. A toner image is formed on the surface of the photosensitive drum by developing the charged toner, which is an agent, by adhering it along the electrostatic latent image. Then, the electrophotographic image forming apparatus transfers the toner image formed on the surface of the photosensitive drum to the transfer paper by being pressed against the rotating photosensitive drum while conveying the transfer paper. By applying pressure while heating the transferred transfer paper, the attached toner is fixed to the transfer paper to form an image.

  As described above, the electrophotographic image forming apparatus is configured to press the transfer paper against the photosensitive drum when transferring the toner image formed on the surface of the photosensitive drum onto the transfer paper. At this time, in a region facing the photosensitive drum (hereinafter referred to as a “transfer region”), it is pressed by a transfer roller that rotates following the transfer of the transfer paper. Further, at this time, the electrophotographic image forming apparatus applies a transfer bias in the transfer region so as to form a transfer electric field between the photosensitive drum and the transfer roller in the transfer region.

  In this way, the electrophotographic image forming apparatus forms a transfer electric field while pressing the transfer paper against the photosensitive drum in the transfer region, thereby transferring the toner image from the photosensitive drum to the transfer paper by the transfer electric field. It is like that. In this manner, the electrophotographic image forming apparatus transfers an image formed on the surface of the photosensitive drum onto a transfer sheet.

  In this way, the electrophotographic image forming apparatus forms an image on the transfer paper by temporarily attaching the toner as a toner image on the photosensitive drum and transferring the attached toner onto the transfer paper. However, at this time, not all of the toner adhered on the photosensitive drum is transferred to the transfer paper. Therefore, the electrophotographic image forming apparatus needs to clean the toner remaining on the surface of the photosensitive drum (hereinafter referred to as “residual toner”) after the image forming operation.

  Therefore, in such an electrophotographic image forming apparatus, the edge portion of the cleaning blade is pressed against the surface of the photosensitive drum from the direction opposite to the rotation direction of the photosensitive drum, so that the edge portion on the surface of the photosensitive drum. Residual toner is cleaned. However, in the electrophotographic image forming apparatus, when the residual toner on the surface of the photosensitive drum is cleaned in this manner, the photosensitive drum is caused by friction between the surface of the photosensitive drum and the edge portion of the cleaning blade. Filming may occur on the surface, the cleaning performance may be degraded, the contact area between the photosensitive drum and the cleaning blade may be severely worn, and frictional noise may be generated between the surface of the photosensitive drum and the edge of the cleaning blade. There are problems such as occurrence.

  As described above, an electrophotographic image forming apparatus forms an electrostatic latent image on a surface of a photosensitive drum by charging the surface of the photosensitive drum with a laser beam. There is a problem that the surface of the photosensitive drum deteriorates due to the charging current.

  Therefore, such an electrophotographic image forming apparatus reduces the frictional force between the surface of the photosensitive drum and the cleaning blade, and also protects the surface from the electric current when charging the surface of the photosensitive drum. In order to achieve this, a lubricant may be applied to the surface of the photosensitive drum. As described above, the electrophotographic image forming apparatus can prevent the above-described problem from occurring by applying a lubricant to the surface of the photosensitive drum (see, for example, Patent Document 1). ).

  However, in such an electrophotographic image forming apparatus, the mode of the toner image formed on the photosensitive drum, for example, the area of the toner image, the density of the toner image, the charge amount of the toner constituting the toner image, etc. The strength of the transfer electric field formed by the transfer bias applied in the transfer region (hereinafter referred to as “transfer electric field strength”) varies. For this reason, in such an electrophotographic image forming apparatus, the transfer rate of the toner image from the photosensitive drum to the transfer paper changes.

  As described above, in the electrophotographic image forming apparatus, when the amount of residual toner on the surface of the photosensitive drum changes, the amount of lubricant applied to the surface of the photosensitive drum also changes. This is because the residual toner on the surface of the photosensitive drum functions as an abrasive for scraping off the lubricant from the solid lubricant.

  As a result, in such an electrophotographic image forming apparatus, the amount of lubricant applied to the surface of the photosensitive drum is too small or excessive depending on the transfer rate of the toner image from the photosensitive drum to the transfer paper. It will become.

  In such an electrophotographic image forming apparatus, when the amount of lubricant applied to the surface of the photosensitive drum becomes too small, there is a high possibility that the above problem will occur. On the other hand, in such an electrophotographic image forming apparatus, when the amount of lubricant applied to the surface of the photosensitive drum becomes excessive, the surface of the charging roller for charging the surface of the photosensitive drum is also applied. When the lubricant adheres to cause poor charging, or in a high humidity environment, the lubricant on the surface of the photosensitive drum absorbs moisture and becomes conductive, and electrostatic latent on the surface of the photosensitive drum. There is a problem that the image is disturbed and the image quality is lowered.

  As described above, in the electrophotographic image forming apparatus, the amount of lubricant applied to the surface of the photosensitive drum affects the transfer rate of the toner image from the photosensitive drum to the transfer paper. The above-mentioned problem occurs when the number becomes excessive or excessive.

  Note that such a problem is not limited to the method in which the toner image is directly transferred from the photosensitive drum to the transfer paper, that is, the toner image is transferred from the photosensitive drum to the intermediate transfer belt. Thereafter, the same may occur in a system in which the intermediate transfer image is transferred onto a transfer sheet, that is, an indirect transfer type image forming apparatus.

  The present invention has been made in view of the above circumstances, and an object thereof is to supply an appropriate amount of lubricant to the surface of an image carrier.

  In order to solve the above-mentioned problems, the amount of lubricant supplied by the lubricant supply unit that supplies the lubricant to the surface of the image carrier that electrostatically carries the developer image composed of the charged developer is reduced. A lubricant supply amount control device for controlling the developer image carried on the image carrier among the developers constituting the developer image carried on the image carrier. A transfer rate estimation unit that estimates a ratio of the amount of developer transferred from the image carrier when the developer image is transferred by electrostatically moving the developer constituting A lubricant supply amount control unit that controls a supply amount of the lubricant per unit time to the surface of the image carrier by the lubricant supply unit according to the estimated ratio. To do.

  According to the present invention, an appropriate amount of lubricant can be supplied to the surface of the image carrier.

1 is a block diagram schematically illustrating a hardware configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a block diagram schematically illustrating a functional configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a cross-sectional view from the main scanning direction of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a cross-sectional view from the main scanning direction of the image forming unit attached to the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a perspective view from above of an image forming unit attached to the image forming apparatus according to the embodiment of the present invention. 6 is a graph showing fluctuations in the amount of lubricant supplied to the photoconductor drum due to the amount of collected leakage toner in the image forming apparatus according to the embodiment of the present invention. 6 is a graph showing a change in the amount of residual toner depending on a primary transfer rate in an image forming apparatus according to an embodiment of the present invention. 6 is a graph showing a change in the amount of collected leakage toner according to the amount of residual toner in the image forming apparatus according to the embodiment of the present invention. 6 is a graph showing a change in the amount of toner that has not been collected due to the primary transfer rate in the image forming apparatus according to the embodiment of the present invention. 5 is a graph showing changes in primary transfer rate due to transfer electric field strength in the image forming apparatus according to the embodiment of the present invention. 5 is a graph showing a change in the amount of recovery-leaked toner due to transfer electric field strength in the image forming apparatus according to the embodiment of the present invention. 6 is a graph showing a change in the amount of lubricant supplied to the photosensitive drum according to the transfer electric field strength in the image forming apparatus according to the embodiment of the present invention. 1 is a cross-sectional view from the main scanning direction of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view of the image forming unit attached to the image forming apparatus according to the embodiment of the present invention from obliquely above. In the image forming apparatus according to the embodiment of the present invention, it is a diagram showing how the transfer electric field intensity varies according to the photosensitive member charging potential. In the image forming apparatus according to an embodiment of the present invention, it is a diagram showing how the transfer charge intensity varies according to the average image area ratio in the main scanning direction. FIG. 5 is a diagram for explaining an average image area ratio in the main scanning direction in the image forming apparatus according to the embodiment of the present invention. In the image forming apparatus according to the embodiment of the present invention, it is a diagram showing how the transfer electric field intensity varies according to the average image density in the main scanning direction. FIG. 5 is a diagram for explaining an average image density in the main scanning direction in the image forming apparatus according to the embodiment of the present invention. It is a figure which shows the relationship between the rotational speed of the lubricant application roller which concerns on embodiment of this invention, and the lubricant supply amount to a photoconductor drum.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, an electrophotographic image forming apparatus will be described as an example. When forming an image on transfer paper, the image forming apparatus according to this embodiment first forms an electrostatic latent image by charging the surface of a photosensitive drum, which is an image carrier, with a laser beam, A toner image as a developer image is formed on the surface of the photosensitive drum by developing the developed developer by adhering the toner as the developer along the electrostatic latent image.

  Then, the image forming apparatus according to the present embodiment transfers the toner image formed on the surface of the photosensitive drum to the transfer paper by being pressed against the rotating photosensitive drum while conveying the transfer paper, and the toner image By applying pressure while heating the transfer paper onto which the toner has been transferred, an image is formed by fixing the adhered toner to the transfer paper.

  As described above, the image forming apparatus according to the present embodiment is configured to press the transfer paper against the photosensitive drum when transferring the toner image formed on the surface of the photosensitive drum to the transfer paper. At this time, an area facing the photosensitive drum (hereinafter referred to as “transfer area”) is pressed by a transfer roller that rotates following the transfer of the transfer paper. Further, at this time, the image forming apparatus according to the present embodiment applies a transfer bias in the transfer region so as to form a transfer electric field between the photosensitive drum and the transfer roller in the transfer region.

  As described above, the image forming apparatus according to the present embodiment forms a transfer electric field while pressing the transfer paper against the photosensitive drum in the transfer region, and transfers the toner image from the photosensitive drum to the transfer paper by the transfer electric field. It is supposed to be. In this way, the image forming apparatus according to the present embodiment is configured to transfer the image formed on the surface of the photosensitive drum onto the transfer sheet.

  As described above, the image forming apparatus according to the present embodiment forms the image on the transfer paper by temporarily attaching the toner as a toner image on the photosensitive drum and transferring the attached toner onto the transfer paper. However, at this time, not all of the toner adhered on the photosensitive drum is transferred to the transfer paper. Therefore, after the image forming operation, the image forming apparatus according to the present embodiment presses the edge portion of the cleaning blade against the surface of the photosensitive drum from the direction opposite to the rotation direction of the photosensitive drum, thereby the photosensitive drum at the edge portion. The toner remaining on the surface (hereinafter referred to as “residual toner”) is cleaned.

  In the image forming apparatus according to the present embodiment, a lubricant is applied to the surface of the photosensitive drum. This reduces the frictional force between the surface of the photosensitive drum and the cleaning blade, thereby preventing problems caused by the friction, and from the current when charging the surface of the photosensitive drum. This is to prevent problems caused by the charging current by protecting the surface.

  However, in such an electrophotographic image forming apparatus, the mode of the toner image formed on the photosensitive drum, for example, the area of the toner image, the density of the toner image, the charge amount of the toner constituting the toner image, etc. The strength of the transfer electric field formed by the transfer bias applied in the transfer region (hereinafter referred to as “transfer electric field strength”) varies. For this reason, in such an electrophotographic image forming apparatus, the transfer rate of the toner image from the photosensitive drum to the transfer paper changes.

  As described above, in the electrophotographic image forming apparatus, when the amount of residual toner on the surface of the photosensitive drum changes, the amount of lubricant applied to the surface of the photosensitive drum also changes. This is because the residual toner on the surface of the photosensitive drum functions as an abrasive for scraping off the lubricant from the solid lubricant.

  As a result, in such an electrophotographic image forming apparatus, the amount of lubricant applied to the surface of the photosensitive drum is too small or excessive depending on the transfer rate of the toner image from the photosensitive drum to the transfer paper. It will become.

  Therefore, in the image forming apparatus according to the present embodiment, the amount of lubricant supplied to the photosensitive drum (hereinafter referred to as “lubricant supply amount”) is set to the transfer rate of the toner image from the photosensitive drum to the transfer paper. One of the gist is to keep the amount within a proper range without being affected.

  First, a hardware configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram schematically illustrating a hardware configuration of the image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 includes an engine for realizing a printer, a scanner, and a facsimile in addition to the hardware configuration shown in FIG.

  As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment includes a configuration similar to that of a general server, a PC (Personal Computer), or the like. That is, the image forming apparatus 1 according to the present embodiment includes a CPU (Central Processing Unit) 10, a RAM (Random Access Memory) 20, a ROM (Read Only Memory) 30, an HDD (Hard Disk Drive) 40, and an I / F 50. 90 is connected. In addition, a display unit 60, an operation unit 70, and a dedicated device 80 are connected to the I / F 50.

  The CPU 10 is a calculation unit and controls the operation of the entire image forming apparatus 1. The RAM 20 is a volatile storage medium capable of reading and writing information at high speed, and is used as a work area when the CPU 10 processes information. The ROM 30 is a read-only nonvolatile storage medium and stores a program such as firmware. The HDD 40 is a non-volatile storage medium that can read and write information, and stores an OS (Operating System), various control programs, application programs, and the like.

  The I / F 50 connects and controls the bus 90 and various hardware and networks. The display unit 60 is a visual user interface for the user to check the state of the image forming apparatus 1 and is realized by a display device such as an LCD (Liquid Crystal Display). The operation unit 70 is a user interface such as a keyboard and a mouse for the user to input information to the image forming apparatus 1. The dedicated device 80 is hardware for realizing a dedicated function in the printer, scanner, and facsimile.

  In such a hardware configuration, a program stored in a storage medium such as the ROM 30, the HDD 40, or an optical disk (not shown) is read into the RAM 20, and the CPU 10 performs an operation according to the program loaded into the RAM 20, whereby the software control unit Is configured. A functional block that realizes the functions of the image forming apparatus 1 according to the present embodiment is configured by a combination of the software control unit configured as described above and hardware.

  Next, the functional configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram schematically illustrating a functional configuration of the image forming apparatus 1 according to the present embodiment. In FIG. 2, the electrical connection is indicated by solid arrows, and the flow of the transfer paper or document bundle is indicated by broken arrows.

  As shown in FIG. 2, the image forming apparatus 1 according to the present embodiment includes a controller 100, a paper feed table 200, a print engine 300, a print paper discharge tray 400, an ADF (Auto Document Feeder) 500, It has a scanner engine 600, a scanning discharge tray 700, a display panel 800, and a network I / F 900. The controller 100 includes a main control unit 110, an engine control unit 120, an image processing unit 130, an operation display control unit 140, and an input / output control unit 150.

  The paper feed table 200 feeds transfer paper to the print engine 300 that is an image forming unit. The print engine 300 is an image forming unit that draws an image by executing an image forming output on the transfer paper conveyed from the paper feed table 200. A specific aspect of the print engine 300 according to the present embodiment is an electrophotographic image forming mechanism. The image-formed transfer sheet on which an image is drawn by the print engine 300 is discharged to the print discharge tray 400. The print engine 300 is realized by the dedicated device 80 shown in FIG.

  The ADF 500 automatically conveys a document to a scanner engine 600 that is a document reading unit. The scanner engine 600 is a document reading unit including a photoelectric conversion element that converts optical information into an electrical signal, and optically scans a document automatically conveyed by the ADF 500 or a document set on a platen glass (not shown). This is a document reading unit that reads and generates image information. A document automatically conveyed by the ADF 500 and read by the scanner engine 600 is discharged to a scanning discharge tray 700. The ADF 500 and the scanner engine 600 are realized by the dedicated device 80 shown in FIG.

  The display panel 800 is an output interface that visually displays the state of the image forming apparatus 1 and is an input when the user directly operates the image forming apparatus 1 or inputs information to the image forming apparatus 1 as a touch panel. It is also an interface. That is, the display panel 800 includes a function for displaying an image for receiving an operation by the user. The display panel 800 is realized by the display unit 60 and the operation unit 70 shown in FIG.

  A network I / F 900 is an interface through which the image forming apparatus 1 communicates with other devices such as an administrator terminal and a PC (Personal Computer) via the network, and is an Ethernet (registered trademark) or a USB (Universal Serial Bus). ) Interface, Bluetooth (registered trademark), Wi-Fi (Wireless Fidelity) (registered trademark), FeliCa (registered trademark), and other interfaces are used. As described above, the image forming apparatus 1 according to the present embodiment receives image data for a print request and various control commands such as a print request from a terminal connected via the network I / F 900. The network I / F 900 is realized by the I / F 50 shown in FIG.

  The controller 100 is configured by a combination of software and hardware. Specifically, a software control unit and an integrated circuit configured by loading a control program such as firmware stored in a non-volatile storage medium such as the ROM 30 or the HDD 40 into the RAM 20 and performing an operation by the CPU 10 according to the program. The controller 100 is configured by hardware such as the above. The controller 100 functions as a control unit that controls the entire image forming apparatus 1.

  The main control unit 110 plays a role of controlling each unit included in the controller 100, and gives a command to each unit of the controller 100. Further, the main control unit 110 controls the input / output control unit 150 and accesses other devices via the network I / F 900 and the network. The engine control unit 120 controls or drives driving units such as the print engine 300 and the scanner engine 600.

  The image processing unit 130 outputs drawing information based on image information described by PDL (Page Description Language), for example, document data or image data included in an input print job, under the control of the main control unit 110. Generate as information. The drawing information is information such as CMYK (Cyan Magenta Yellow Key Plate) bitmap data, and is information for drawing an image to be formed by the print engine 300 as an image forming unit in an image forming operation.

  Further, the image processing unit 130 processes image data input from the scanner engine 600 and generates image data. The image data is information stored in the image forming apparatus 1 as a result of the scanner operation or transmitted to another device via the network I / F 900 and the network. Note that the image forming apparatus 1 according to the present embodiment can directly input drawing information instead of image information, and can execute image forming output based on the directly input drawing information.

  The operation display control unit 140 displays information on the display panel 800 or notifies the main control unit 110 of information input via the display panel 800. The input / output control unit 150 inputs signals and commands input via the network I / F 900 and the network to the main control unit 110.

  Next, a detailed configuration of the print engine 300 according to the present embodiment will be described with reference to FIGS. FIG. 3 is a cross-sectional view from the main scanning direction of the image forming apparatus 1 according to the present embodiment. FIG. 4 is a cross-sectional view from the main scanning direction of the image forming unit 320 attached to the image forming apparatus 1 according to the present embodiment. FIG. 5 is a transparent view from above of the image forming unit 320 attached to the image forming apparatus 1 according to the present embodiment.

  As shown in FIG. 3, the image forming apparatus 1 according to the present embodiment forms an image on the transfer paper 2 fed from the paper feed table 200 by the print engine 300, and then places the image on the print paper discharge tray 400. It has a configuration for discharging paper.

  As shown in FIG. 3, the print engine 300 according to the present embodiment includes a configuration in which the image forming units 320 of the respective colors are arranged along the endless conveying unit 310, and is referred to as a so-called tandem type. Is. That is, the print engine 300 according to this embodiment includes a plurality of image forming units in order from the upstream side in the transport direction of the transport belt 311 along the transport belt 311 spanned between the driving roller 312 and the driven roller 313. The C plate image forming unit 320C, the M plate image forming unit 320M, the Y plate image forming unit 320Y, and the K plate image forming unit 320K are arranged.

  The plurality of image forming units 320C, 320M, 320Y, and 320K have the same internal configuration except that the color of the toner image to be formed is different. The C plate image forming unit 320C forms a cyan image, the M plate image forming unit 320M forms a magenta image, the Y plate image forming unit 320Y forms a yellow image, and the K plate image forming unit 320K forms a black image. . In the following description, the C plate image forming unit 320C will be described in detail, but the other image forming units 320M, 320Y, and 320K are the same as the C plate image forming unit 320C, and therefore other image forming units. The constituent elements of 320M, 320Y, and 320K are replaced with C attached to the respective constituent elements of the C-plate image forming unit 320C, and only the symbols distinguished by M, Y, and K are displayed in the figure, and the description thereof is omitted. To do.

  The conveying belt 311 is made of a heat-resistant material such as polyimide or polyamide, and is an endless belt, ie, an endless belt, which is stretched between a driving roller 312 and a driven roller 313 that are rotationally driven. This is an intermediate transfer belt on which an intermediate transfer image is formed by the unit, the C plate image forming unit 320C, the M plate image forming unit 320M, the Y plate image forming unit 320Y, and the K plate image forming unit 320K. The drive roller 312 is driven to rotate by a drive motor (not shown), and the drive motor, the drive roller 312 and the driven roller 313 move the conveyor belt 311.

  The C-plate image forming unit 320 </ b> C forms a cyan intermediate transfer image on the transport belt 311. As shown in FIGS. 4 and 5, the C plate image forming unit 320C includes a photosensitive drum 321C as a photosensitive member, a charging unit 322C disposed around the photosensitive drum 321C, a developing unit 323C, and a static eliminator. 324C, a toner recovery unit 325C, a lubricant application unit 326C, and a lubricant uniformizing blade 327C. The C plate image forming unit 320C may be configured independently. However, the charging unit 322C, the developing unit 323C, the charge eliminator 324C, the toner collecting unit 325C, the lubricant applying unit 326C, and the lubricant uniformizing blade. At least one of 327 </ b> C and the photosensitive drum 321 </ b> C may be configured integrally, and may be configured as a process cartridge that is detachable from the image forming apparatus 1.

  The C-plate image forming unit 320C configured as described above applies a lubricant onto the surface of the photosensitive drum 321C by a lubricant application unit 326C prior to image formation, and applies the applied lubricant to a lubricant uniformizing blade. It is averaged and fixed on the surface of the photosensitive drum 321C by 327C so as to have a uniform thickness. The photosensitive drum 321C is composed of an aluminum cylindrical base and a photosensitive layer covering the surface thereof, and is driven to rotate. The photosensitive layer is made of, for example, an organic photoreceptor (OPC: Organic Photoconductor).

  At this time, the powdery lubricant applied on the surface of the photosensitive drum 321C has a weak adhesion to the surface of the photosensitive drum 321C immediately after application, but is leveled by the lubricant uniformizing blade 327C. As a result, the film is gradually thinned to become a finer powder, and the adhesive force with the surface of the photosensitive drum 321C is gradually increased and fixed. The particle size of the powdery lubricant according to the present embodiment is about several tens of μm to several hundreds of μm immediately after application to the surface of the photosensitive drum 321C, and is more than the particle size of the toner according to the present embodiment. Is also big.

  As described above, the reason for applying the lubricant on the surface of the photosensitive drum 321C prior to image formation is to reduce the coefficient of friction between the surface of the photosensitive drum 321C and the mechanism portion in contact therewith. In order to suppress the occurrence of a filming phenomenon on the surface of the photosensitive drum 321C, to reduce wear of the contact portion between the photosensitive drum 321C and the mechanism portion, or to a toner recovery unit. For example, 325C may improve efficiency when collecting toner remaining on the surface of the photosensitive drum 321C, or a frictional noise may be generated between the surface of the photosensitive drum 321C and the edge portion of the cleaning blade. It is for preventing.

  In addition, the reason for applying the lubricant on the surface of the photosensitive drum 321C prior to image formation is that the charging unit 322C protects the surface from the current when the surface of the photosensitive drum 321C is charged. This is to prevent a problem that the surface of the photosensitive drum 321C is consumed due to the charging current at that time.

  The lubricant applied on the surface of the photosensitive drum 321C deteriorates and wears over time or with the driving of the photosensitive drum 321C. By applying from 326C, the effect of lubricant application can be continuously obtained.

  As shown in FIG. 4, the lubricant application unit 326C according to the present embodiment is disposed on the downstream side of the toner recovery unit 325 in the rotational direction of the photosensitive drum 321C, and on the upstream side of the image forming unit 320C. Is arranged. As shown in FIG. 4, the lubricant application unit 326C according to this embodiment includes a solid lubricant 326a, a lubricant application roller 326b, and a solid lubricant pressing spring 326c.

  The solid lubricant 326a is most commonly zinc stearate ZnSt, but in this embodiment, a fatty acid metal salt, that is, a metal soap to which an inorganic lubricant is added is preferable.

  The lubricant application roller 326b is disposed at a position facing the photosensitive drum 321C, and scrapes off the solid lubricant 326a by rotating following the photosensitive drum 321C while contacting the photosensitive drum 321C and the solid lubricant 326a. Then, the shaved lubricant is applied to the photosensitive drum 321. That is, in the present embodiment, the lubricant application roller 326b functions as a lubricant supply unit. The core material of the lubricant application roller 326b may be a round bar-shaped shaft made of a metal such as iron, aluminum, or stainless steel, or a resin such as an epoxy resin or a phenol resin. The material, shape, size, structure, and the like are not particularly limited as long as they have a desired strength necessary for exhibiting the function of coating.

  The solid lubricant pressing spring 326c is a compression spring that generates a pressing force for pressing the solid lubricant 326a against the lubricant application roller 326b. As described above, in this embodiment, an example in which the pressing force generated by the compression spring is used to press the solid lubricant 326a against the lubricant application roller 326b will be described. It may be configured to use a pressing force to be generated or a pressing force generated by a weight. Note that it is preferable to use the pressing force generated by the compression spring from the balance of function, space, and cost.

  When the lubricant is applied onto the surface of the photosensitive drum 321C as described above, the C plate image forming unit 320C forms a cyan intermediate transfer image on the conveyor belt 311 during image formation. That is, the C-plate image forming unit 320C first charges the surface of the photosensitive drum 321C uniformly by the charging unit 322C in the dark when forming an image. Then, the C plate image forming unit 320C performs electrostatic writing by irradiating the uniformly charged photosensitive drum 321C with light corresponding to the cyan image from the optical writing device 330C, and the surface of the photosensitive drum 321C. Then, an electrostatic latent image corresponding to the cyan image is formed.

  The optical writing device 330C according to this embodiment reflects light emitted from a light source including a laser diode by a polygon mirror or the like, and sequentially scans the reflected light onto the photosensitive drum 321C. Electrostatic writing is performed on the body drum 321C.

  As shown in FIG. 4, the charging unit 322C according to this embodiment includes a charging roller 322a and a charging roller cleaner 322b. When the charging roller 322a is applied with a charging bias and approaches the surface of the photosensitive drum 321C, the charging roller 322a uniformly charges the surface of the photosensitive drum 321C by the action of the applied charging bias.

  The charging roller cleaner 322b contacts the charging roller 322a to remove dirt on the surface of the charging roller 322a. As described above, as a reason for removing the dirt on the surface of the charging roller 322a, when the surface of the charging roller 322a is dirty, the charging ability of the part to which the dirt is attached is reduced, and the photosensitive drum 321C is charged to a target potential. This is to prevent the occurrence of abnormal images due to poor charging.

  As the charging roller cleaner 322b, a flocking roller in which fibers are electrostatically flocked on a metal shaft, a melamine roller in which a melamine resin is arranged around the metal shaft, and the like are used. A melamine roller that can be used for a relatively long time is used. There are many cases. If slip occurs between the charging roller 322a and the charging roller cleaner 322b, the dirt is rubbed against the surface of the charging roller 322b, and the generation of an abnormal image due to the dirt is accelerated. Accordingly, the charging roller 322a and the charging roller cleaner 322b are configured to rotate around.

  As the charging roller 322a, a non-contact scorotron method, a corotron method, a contact roller charging method using a medium resistance rubber roller, a non-contact roller charging method, or the like is generally used. The charging roller 322a according to the present embodiment employs a non-contact roller charging method, but other methods may be used. Note that both the contact roller charging method and the non-contact roller charging method include a method of superimposing alternating current on direct current and a method of applying only direct current.

  When the alternating current is superimposed on the direct current in the contact roller charging system and the non-contact charging roller system, high image quality can be obtained as compared with the direct current alone, but the filming phenomenon is likely to occur in the photosensitive drum 321. Further, if the alternating current is controlled at a constant current, there is an advantage that the influence on the photosensitive member charging potential caused by the change in the resistance value of the charging roller 322a due to the environmental change can be reduced. May be a problem. On the other hand, when only DC is applied, the change in the resistance value of the charging roller due to the environmental change affects the photosensitive member charging potential. To reduce this influence, the charging bias is corrected according to the environmental change, etc. Countermeasures are required.

  As described above, when the contact charging roller method and the non-contact charging roller method are compared, the non-contact charging roller method causes unevenness in the image due to the influence of the gap fluctuation between the surface of the photosensitive member and the charging roller when the alternating current is controlled. Therefore, it is necessary to take measures such as correcting the charging bias in order to reduce this influence. On the other hand, in the non-contact charging roller system, the charging roller is less likely to get dirty as much as the charging roller is not in contact with the surface of the photoconductor as compared with the contact charging roller system.

  As a method of correcting the charging bias, a method of detecting the temperature in the vicinity of the charging roller 322a and changing the charging bias, and a method of changing the charging bias by periodically detecting ground contamination on the surface of the photosensitive drum 321 are used. And a method of changing the charging bias according to a charging bias feedback current value. Further, as a driving method of the charging roller 322a, there is a method of rotating the charging roller 322a by transmitting the driving force from the photoconductor gear or the like to the charging roller 322a. As described above, the contact charging roller method is used. If so, it is possible to employ a method in which the charging roller 322a is brought into contact with the surface of the photosensitive drum 321 and the charging roller 322a is rotated along with the movement of the surface of the photosensitive drum 321.

  When the electrostatic latent image corresponding to the cyan image is formed on the surface of the photosensitive drum 321C as described above, the C plate image forming unit 320C causes the developing unit 323C to convert the electrostatic latent image with cyan toner. By making the image visible, a cyan toner image is formed on the surface of the photosensitive drum 321C.

  As shown in FIGS. 4 and 5, the developing unit 323C according to this embodiment includes a first developer conveying screw 323a, a second developer conveying screw 323b, and a developing roller 323c. The developing roller 323c is disposed at a position facing the photoconductor drum 323C, and generates a magnetic field therein, thereby serving as a toner carrier that carries toner to adhere to the photoconductor drum 321C.

  The first developer conveying screw 323a and the second developer conveying screw 323b are disposed below the developing roller 323c, and rotate in directions opposite to each other, whereby a toner supply mechanism (not shown) from the toner bottle 350C. The cyan toner supplied by is conveyed while being stirred with the carrier so as to spread over the entire main scanning direction. At this time, the toner and carrier conveyed to the end of the developing unit 323c by the first developer conveying screw 323a are transferred to the other second developer conveying screw 323b, and the second developer conveying screw 323b. The toner and the carrier conveyed to the other end of the developing unit 323c are circulated so as to reach the entire main scanning direction in the developing unit 323C by being transferred to the other first developer conveying screw 323a. Be transported.

  The developer conveyed by the second developer conveying screw 323b is pumped and adhered to the surface by a magnetic field generated inside the developing roller 323c, and is conveyed along with the rotation of the developing roller 323c. After being regulated to a predetermined layer thickness by the doctor blade, it is conveyed to a facing area facing the photosensitive drum 323C, that is, an area for developing an electrostatic latent image (hereinafter referred to as “developing area”). That is, in the present embodiment, the developing unit 323 functions as a developer container.

  In this way, the toner in the developer that has been transported to the developing area is applied to the surface of the photosensitive drum 321C in the developing area by the action of the developing bias generated between the developing roller 323c and the photosensitive drum 321C. It electrostatically moves to an electrostatic latent image corresponding to the formed cyan image and adheres to the surface of the photosensitive drum 321C. In this way, the developing unit 323C forms a cyan toner image on the surface of the photosensitive drum 321C by visualizing the electrostatic latent image with cyan toner.

  In this embodiment, an example of a two-component development method will be described, but a one-component development method may be used. In other words, the image forming apparatus 1 according to the present embodiment is not limited to a two-component developer including a toner and a carrier, but is an image forming apparatus that uses a one-component developer including a magnetic toner containing magnetic powder in the toner. May be.

  The C-plate image forming unit 320C displays the toner image in a region where the photosensitive drum 321C and the transport belt 311 are in contact with or closest to each other (hereinafter referred to as “primary transfer region”), and the primary transfer roller 340C is not illustrated. By being pressed against the photosensitive drum 321C by the urging member, the image is transferred onto the conveying belt 311.

  By this transfer, an image of cyan toner, that is, a cyan intermediate transfer image is formed on the conveyance belt 311. At this time, the C plate image forming unit 320C applies a transfer bias in the primary transfer area so as to form a transfer electric field between the photosensitive drum 321C and the primary transfer roller 340C in the primary transfer area. As a result, the cyan toner image formed on the surface of the photosensitive drum 321C is transferred to the transport belt 311 in the primary transfer region. In this way, the C plate image forming unit 320C applies a transfer bias while pressing the transfer paper against the photoconductive drum 321C in the primary transfer region, whereby a cyan toner image formed on the surface of the photoconductive drum 321C, That is, a cyan intermediate transfer image is formed on the conveyance belt 311. That is, in the present embodiment, a transfer electric field is applied as a transfer voltage.

  When the C plate image forming unit 320C finishes forming the cyan intermediate transfer image on the conveyance belt 311, the toner collecting unit 325C collects the toner (residual toner) remaining on the surface of the photoconductive drum 321C, and then the photoconductor. The surface of the drum 321C is neutralized by the static eliminator 324C, and ready for the next image formation, for example, supply of cyan toner from the toner bottle 350C to the developing unit 323C by a toner supply mechanism (not shown) and waits. The toner bottle 350 </ b> C is configured to be removable from the image forming apparatus 1 by opening a printing paper discharge tray 400 formed on the upper part of the image forming apparatus 1. It should be noted that the replenishment of toner from the toner bottle 350C to the developing unit 323C is performed as needed at a predetermined timing, not immediately after the image forming operation.

  As shown in FIG. 4, the toner recovery unit 325C according to this embodiment includes a cleaning blade 325a, a recovery toner transport screw 325b, and a recovery toner transport path 325c.

  The cleaning blade 325a is configured such that an edge portion made of an elastic material such as urethane rubber is pressed against the surface of the cleaning blade 325a from the direction facing the rotation direction of the photosensitive drum 321C. The toner remaining on the surface of the toner is scraped off, and the scraped toner is collected in the collected toner conveyance path 325c. That is, in the present embodiment, the cleaning blade 325a functions as a developer removing unit that removes the developer remaining on the surface of the image carrier.

  The collected toner conveying screw 325b conveys the toner collected in the collected toner conveying path 325c (hereinafter referred to as “collected toner”) along the collected toner conveying path 325c. The collected toner transported in this manner is transported toward a waste toner storage container (not shown) that is a container for storing the discarded toner and discarded, or transported toward the developing unit 323C. Reused.

  At this time, when the residual toner is recovered by the toner recovery unit 325C, not all of the residual toner is recovered. Therefore, the toner that is not collected and remains on the surface of the photosensitive drum 321C (hereinafter referred to as “collected leakage toner”) directly faces the lubricant application roller 326b as the photosensitive drum 321C rotates. It is conveyed to the position, and a part thereof adheres to the surface of the lubricant application roller 326b. The toner adhered to the surface of the lubricant application roller 326b functions as an abrasive for the lubricant application roller 326b to scrape the lubricant from the solid lubricant 326a.

  For this reason, in the image forming apparatus 1 according to the present embodiment, the amount of lubricant supplied to the photosensitive drum 321C varies depending on the amount of collected leakage toner. Specifically, as shown in FIG. 6, in the image forming apparatus 1 according to the present embodiment, the larger the amount of the recovery leakage toner, the more lubricant is supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C. Will be supplied to.

  In the image forming apparatus 1 according to the present embodiment, the amount of the collected leakage toner varies depending on the strength of the transfer electric field (transfer electric field strength) formed by the transfer bias applied in the primary transfer region. Here, the reason will be described with reference to FIGS.

  FIG. 7 is a graph showing changes in the amount of residual toner depending on the primary transfer rate in the image forming apparatus 1 according to the present embodiment. FIG. 8 is a graph showing a change in the amount of collected leakage toner due to the amount of residual toner in the image forming apparatus 1 according to the present embodiment. FIG. 9 is a graph showing a change in the amount of the recovery leakage toner according to the primary transfer rate in the image forming apparatus 1 according to the present embodiment. FIG. 10 is a graph showing changes in the primary transfer rate depending on the transfer electric field strength in the image forming apparatus 1 according to the present embodiment. FIG. 11 is a graph showing a change in the amount of the recovery leakage toner due to the transfer electric field strength in the image forming apparatus 1 according to the present embodiment. FIG. 12 is a graph showing a change in the amount of lubricant supplied to the photosensitive drum 321 due to the transfer electric field strength in the image forming apparatus 1 according to the present embodiment.

  As shown in FIG. 7, in the image forming apparatus 1 according to the present embodiment, the amount of residual toner is the ratio of toner transferred from the photosensitive drum 321C to the conveyance belt 311 (hereinafter referred to as “primary transfer rate”). ) Will vary. Specifically, as shown in FIG. 7, the amount of residual toner increases as the primary transfer rate increases. This is because as the primary transfer rate increases, more toner is transferred from the photosensitive drum 321 to the transport belt 311.

  Further, as shown in FIG. 8, in the image forming apparatus 1 according to the present embodiment, the amount of the recovery leakage toner varies depending on the amount of residual toner. Specifically, as shown in FIG. 8, the amount of the recovery omission toner increases as the amount of residual toner increases. This is because when the residual toner is recovered by the toner recovery unit 325C, not all of the residual toner is recovered. As the amount of residual toner increases, the toner passes through the gap between the photosensitive drum 321 and the cleaning blade 325a. This is because the amount of residual toner increases and the amount of residual toner that is not recovered by the toner recovery unit 325C increases.

  Therefore, due to the relationship shown in FIGS. 7 and 8, as shown in FIG. 9, in the image forming apparatus 1 according to the present embodiment, the amount of the recovery omission toner varies depending on the primary transfer rate. Specifically, as shown in FIG. 9, the amount of the recovery omission toner decreases as the primary transfer rate increases.

  As shown in FIG. 10, in the image forming apparatus 1 according to the present embodiment, the primary transfer rate varies depending on the transfer electric field strength.

  Therefore, due to the relationship shown in FIGS. 9 and 10, as shown in FIG. 11, in the image forming apparatus 1 according to the present embodiment, the amount of collected leakage toner varies depending on the transfer electric field strength. For this reason, in the image forming apparatus 1 according to the present embodiment, the amount of the recovery leakage toner varies depending on the transfer electric field strength. The reason why the transfer electric field intensity varies will be described later with reference to FIGS.

  As shown in FIG. 11, when the amount of collected leakage toner varies depending on the transfer electric field strength, the amount of lubricant supplied to the photosensitive drum 321C varies depending on the amount of collected leakage toner, as shown in FIG. Therefore, as shown in FIG. 12, it fluctuates depending on the transfer electric field strength. For this reason, the amount of lubricant supplied to the photosensitive drum 321C becomes too small or excessive depending on the intensity of the transfer electric field.

  When the amount of lubricant supplied to the surface of the photosensitive drum becomes too small, filming phenomenon on the surface of the photosensitive drum due to friction between the surface of the photosensitive drum and the edge portion of the cleaning blade. Problems such as the occurrence of noise, degradation of the cleaning performance, severe contact wear between the photosensitive drum and the cleaning blade, and frictional noise between the surface of the photosensitive drum and the edge of the cleaning blade. Is likely to occur. In addition, when the amount of lubricant supplied to the surface of the photosensitive drum becomes too small, there is a problem that the surface of the photosensitive drum is consumed by a charging current when the surface of the photosensitive drum is charged with laser light. .

  On the other hand, if the amount of lubricant supplied to the surface of the photosensitive drum becomes excessive, the lubricant will also adhere to the surface of the charging roller for charging the surface of the photosensitive drum, resulting in poor charging. In particular, in a high humidity environment, the lubricant on the surface of the photosensitive drum absorbs moisture and becomes conductive, disturbing the electrostatic latent image on the surface of the photosensitive drum and causing deterioration in image quality. There is a problem such as.

  Therefore, the image forming apparatus 1 according to the present embodiment uses the fact that the amount of lubricant supplied to the photosensitive drum 321C varies depending on the amount of the collected leakage toner, thereby controlling the amount of the collected leakage toner. The amount of lubricant supplied per unit time from the agent coating unit 326C to the surface of the photosensitive drum 321C is controlled. At this time, the image forming apparatus 1 according to the present embodiment controls the amount of lubricant supplied to the photosensitive drum 321C by the main control unit 110 and the engine control unit 120. That is, in this embodiment, the main control unit 110 and the engine control unit 120 function as a lubricant supply amount control unit, and the controller 100 including the main control unit 110 and the engine control unit 120 functions as a lubricant supply amount control device. To do.

  In particular, the image forming apparatus 1 according to the present embodiment controls the amount of collected leakage toner in accordance with the primary transfer rate, so that the amount of lubricant supplied to the photosensitive drum 321C per unit time becomes the primary transfer rate. It is configured to control accordingly. The gist of the image forming apparatus 1 according to the present embodiment is configured as described above. At this time, the image forming apparatus 1 according to the present embodiment is configured to estimate the primary transfer rate by the main control unit 110 and the engine control unit 120. That is, in the present embodiment, the main control unit 110 and the engine control unit 120 function as a transfer rate estimation unit.

  In other words, when the primary transfer rate is low, the image forming apparatus 1 according to the present embodiment controls the amount of the collected leakage toner to be small so that the lubricant supply unit 326C can transfer the surface of the photosensitive drum 321C. It is configured to prevent an excessive amount of lubricant from being supplied. As a result, the image forming apparatus 1 according to the present embodiment can apply an appropriate amount of lubricant to the surface of the photosensitive drum 321C even when the primary transfer rate is low.

  On the contrary, the image forming apparatus 1 according to the present embodiment controls the surface of the photosensitive drum 321C from the lubricant supply unit 326C by controlling the amount of the collected leakage toner to be increased when the primary transfer rate is high. It is configured to prevent the amount of lubricant supplied to the battery from becoming too small. As a result, the image forming apparatus 1 according to the present embodiment can apply an appropriate amount of lubricant to the surface of the photosensitive drum 321C even when the primary transfer rate is high.

  As described above, the image forming apparatus 1 according to the present embodiment controls the amount of the recovery-leaked toner according to the primary transfer rate, so that the lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C can be obtained. Configured to control the amount. As a result, the image forming apparatus 1 according to the present embodiment can keep the amount of lubricant supplied to the photosensitive drum 321C by the lubricant application unit 326C within an appropriate range without being affected by the primary transfer rate. Become.

  As described above, the image forming apparatus 1 according to the present embodiment can keep the amount of lubricant supplied to the photosensitive drum 321C by the lubricant application unit 326C within an appropriate range without being affected by the primary transfer rate. Therefore, the occurrence of the above-described problem can be suppressed. For a specific method for keeping the amount of lubricant supplied to the photosensitive drum 321C by the lubricant application unit 326C within the appropriate range without being affected by the primary transfer rate, refer to FIGS. Will be described later.

  As described above, the cyan toner image transferred onto the conveying belt 311 by the C-plate image forming unit 320C, that is, the cyan intermediate transfer image, is conveyed by the driving belt, the driving roller 312 and the driven roller 313. By moving 311, the image is conveyed to the next M-plate image forming unit 320 </ b> M. The M plate image forming unit 320M forms a magenta toner image on the photosensitive drum 321M by a process similar to the image forming process in the C plate image forming unit 320C, and the magenta toner image is formed on the cyan toner image already formed. The image is transferred onto the conveyance belt 311 so as to be superimposed on the intermediate transfer image. By this transfer, an image of magenta toner, that is, a magenta intermediate transfer image is formed on the conveyance belt 311. In this way, an intermediate transfer image of cyan and magenta is formed on the conveyance belt 311.

  The cyan and magenta intermediate transfer images formed on the conveying belt 311 are further sequentially conveyed to the next image forming unit, Y plate image forming unit 320Y, and K plate image forming unit 320K, and the photosensitive drum is similarly operated. The yellow toner image formed on 321Y and the black toner image formed on the photosensitive drum 321K are superimposed on the intermediate transfer image already formed and transferred onto the conveying belt 311. By this transfer, an image with yellow toner and an image with black toner, that is, an intermediate transfer image of yellow and black are formed on the conveyance belt 311. Thus, a full-color intermediate transfer image is formed on the conveyance belt 311.

  As described above, since the image forming apparatus 1 according to the present embodiment is a tandem type image forming apparatus, the primary transfer rate in the upstream image forming unit 320 and the primary transfer rate in the downstream image forming unit 320 are as follows. Depending on the difference, the toner of the intermediate transfer image transferred by the upstream photosensitive drum 321 may be reversely transferred to the downstream photosensitive drum 321. Therefore, in such a case, the reversely transferred toner (hereinafter referred to as “reverse transfer toner”) adheres to the downstream surface of the photosensitive drum 321 in addition to the collected leakage toner. The amount of lubricant supplied to the photosensitive drum 321 increases and becomes excessive.

  Therefore, in consideration of such a case, the image forming apparatus 1 according to the present embodiment controls the amount of the recovery leakage toner according to the primary transfer rate, so that the lubricant application unit 326C controls the photosensitive drum 321C. It is meaningful to control the amount of lubricant supplied to the surface of the toner according to the primary transfer rate.

  When a full-color intermediate transfer image is formed on the transport belt 311 in this way, the transfer paper 2 stored in the paper feed table 200 is separated by the paper feed roller 210 and the separation roller pair 220 in order from the top. The paper is fed and sent toward the registration roller pair 230. Then, after the skew of the transfer sheet 2 is corrected by the registration roller pair 230, the transfer sheet 2 and the transfer belt 311 abut on the transfer path in accordance with the transfer timing of the transfer belt 311 by the registration roller pair 230 or It is conveyed to the closest area (hereinafter referred to as “secondary transfer area”).

  The transfer sheet 2 thus transported is a full color formed on the transport belt 311 by the secondary transfer roller 360 being pressed against the driven roller 313 by a biasing member (not shown) in the secondary transfer region. The intermediate transfer image is transferred. As a result, an image is formed on the surface of the transfer paper 2. The transfer paper 2 on which the image is formed on the paper surface is further conveyed, and is sandwiched from the direction perpendicular to the image formation surface by the fixing unit 370 and is heated and pressed to fix the image, and then discharged. The paper is discharged to the print paper discharge tray 400 by the paper roller pair 410.

  Note that the fixing unit 370 according to the present embodiment includes a pair of fixing rollers 371 for rotating the transfer paper 2 while pressing the transfer paper 2 from a direction perpendicular to the image forming surface to convey and pressurize the transfer paper 2. Further, a heating element is provided on the fixing surface of the fixing roller pair 371, and the fixing unit 370 according to the present embodiment heats the transfer paper 2 by the fixing roller pair 371. As described above, the fixing unit 370 according to the present embodiment is configured to fix the image by heating and pressing the transfer paper 2 by sandwiching the transfer paper 2 from the direction perpendicular to the image forming surface by the fixing roller pair 371.

  The belt cleaner 380 scrapes off toner adhering to the surface of the conveyance belt 311 by a cleaning blade pressed against the conveyance belt 311 on the downstream side of the secondary transfer area and upstream of the C-plate image forming unit 320C. Then, the conveyor belt 311 is cleaned.

  As described above, in this embodiment, printing is performed by the endless conveyance unit 310, the image forming unit 320, the optical writing device 330, the primary transfer roller 340, the toner bottle 350, the secondary transfer roller 360, the fixing unit 370, and the belt cleaner 380. An engine 300 is configured.

  As shown in FIG. 3, in this embodiment, an intermediate transfer image is formed on the conveyance belt 311 and the intermediate transfer image is transferred onto a transfer sheet, that is, an indirect transfer type image forming apparatus. However, the present invention can also be applied to a method in which an image is directly formed on a transfer sheet, that is, an image forming apparatus of a direct transfer method as shown in FIG.

  Next, a detailed configuration of the toner recovery unit 325 according to the present embodiment will be described with reference to FIGS. 4 and 14. FIG. 4 is a cross-sectional view from the main scanning direction of the image forming unit 320 attached to the image forming apparatus 1 according to the present embodiment as described above. FIG. 14 is a perspective view of the image forming unit 320 attached to the image forming apparatus 1 according to the present embodiment from obliquely above.

  As shown in FIGS. 4 and 14, the toner recovery unit 325 according to the present embodiment includes a cleaning blade position control roller 325d in addition to the cleaning blade 325a, the recovered toner transport screw 325b, and the recovered toner transport path 325c described above. .

  As described above, the cleaning blade 325a pushes the toner remaining on the surface of the photosensitive drum 321C at the edge portion when the edge portion is pressed against the surface of the photosensitive drum 321C from the direction facing the rotation direction of the photosensitive drum 321C. However, as another characteristic configuration, it is configured to be movable in a direction perpendicular to the main scanning direction. The cleaning blade 325a is supported by being pressed against the cleaning blade position control roller 325d in the moving direction by a biasing member (not shown).

  The cleaning blade position control roller 325d has a cross-sectional shape from the rotation axis direction of the photosensitive drum 321C, that is, from the main scanning direction, excluding a perfect circle, and by controlling the rotation angle of the engine control unit 120, The movement of the cleaning blade 325a is controlled by rotating about a direction parallel to the main scanning direction while supporting the pressed cleaning blade 325a. That is, the cleaning blade position control roller 325d according to the present embodiment can control the positional relationship between the cleaning blade 325a and the photosensitive drum 321C by rotating about a direction parallel to the main scanning direction as a rotation axis. It is configured as follows. In the present embodiment, the positional relationship between the cleaning blade 325a and the photosensitive drum 321C includes, for example, the contact angle of the edge portion of the cleaning blade 325a to the photosensitive drum 321C, the cleaning blade 325a and the photosensitive drum 321C. Distance, etc.

  The cleaning blade position control roller 325d according to the present embodiment controls the positional relationship between the cleaning blade 325a and the photosensitive drum 321C in this manner, so that the contact pressure of the cleaning blade 325a on the surface of the photosensitive drum 321C is controlled. Can be controlled. The cleaning blade position control roller 325d according to the present embodiment controls the contact pressure of the cleaning blade 325a to the surface of the photosensitive drum 321C in this way, so that the lubricant application unit 326C can control the photosensitive drum. It becomes possible to control the amount of lubricant supplied per unit time to the surface of 321C.

  As described above, the cleaning blade position control roller 325d according to this embodiment controls the contact pressure so that the lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C per unit time is supplied. The reason why the amount can be controlled is that the toner that slips between the cleaning blade 325a and the photosensitive drum 321C and remains on the surface of the photosensitive drum 321C (collected leakage toner) according to the contact pressure. This is because the amount of change.

  Specifically, the smaller the contact pressure, the larger the amount of toner (collected leakage toner) that slips between the cleaning blade 325a and the photosensitive drum 321C and remains on the surface of the photosensitive drum 321C. is there. On the other hand, as the contact pressure increases, the amount of toner (recovered leakage toner) that passes between the cleaning blade 325a and the photosensitive drum 321C and remains on the surface of the photosensitive drum 321C tends to decrease.

  As described above, the cleaning blade position control roller 325d according to this embodiment rotates from the lubricant application unit 326C to the surface of the photosensitive drum 321C per unit time by rotating about a direction parallel to the main scanning direction. The amount of lubricant supplied can be controlled.

  In addition, the image forming apparatus 1 according to the present embodiment controls the rotation of the cleaning blade position control roller 325d according to the primary transfer rate under the control of the engine control unit 120, and thus according to the primary transfer rate. It is comprised so that the said contact pressure may be controlled. Thereby, the image forming apparatus 1 according to the present embodiment can control the amount of lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C according to the primary transfer rate. .

  In particular, when the primary transfer rate is low, the image forming apparatus 1 according to the present embodiment controls the rotation of the cleaning blade position control roller 325d so that the contact pressure becomes large, so that the lubricant application unit 326C. To the surface of the photosensitive drum 321C so that the amount of lubricant supplied per unit time is reduced. Accordingly, in the image forming apparatus 1 according to the present embodiment, the amount of the lubricant supplied from the lubricant supply unit 326C to the surface of the photosensitive drum 321C becomes excessive even when the primary transfer rate is low. And an appropriate amount of lubricant can be applied to the surface of the photosensitive drum 321C.

  On the other hand, when the primary transfer rate is high, the image forming apparatus 1 according to the present embodiment controls the rotation of the cleaning blade position control roller 325d so that the contact pressure becomes small, so that the lubricant application unit 326C. To the surface of the photosensitive drum 321C so that the amount of lubricant supplied per unit time is increased. Accordingly, in the image forming apparatus 1 according to the present embodiment, even when the primary transfer rate is high, the amount of lubricant supplied from the lubricant supply unit 326C to the surface of the photosensitive drum 321C becomes too small. And an appropriate amount of lubricant can be applied to the surface of the photosensitive drum 321C.

  As a result, the image forming apparatus 1 according to the present embodiment can keep the amount of lubricant supplied to the photosensitive drum 321C by the lubricant application unit 326C within an appropriate range without being affected by the primary transfer rate. Become.

  The toner that has passed through the cleaning blade 325a and the photosensitive drum 321C and remained on the surface of the photosensitive drum 321C (recovered leakage toner), and has not adhered to the lubricant application roller 326b, Since it is blocked by the lubricant uniformizing roller 327, the subsequent image forming operation is not affected.

  Next, in the image forming apparatus 1 according to the present embodiment, the first factor that causes the transfer electric field strength to change will be described with reference to FIG. FIG. 15 is a diagram showing how the transfer electric field intensity varies in accordance with the photosensitive member charging potential in the image forming apparatus 1 according to the present embodiment. In FIG. 15, a case where the toner image A is formed on the photosensitive drum 321 will be described as an example.

  As described above, in the image forming apparatus 1 according to the present embodiment, the surface of the photosensitive drum 321 is first uniformly charged by the charging unit 322 when forming an image. At this time, the charging potential (photosensitive member charging potential) on the surface of the photosensitive drum 321 is determined according to the charge amount of the toner in the developing unit 323. That is, in the present embodiment, the photosensitive member charging potential is applied as a charging voltage for uniformly charging the image carrier.

  Here, the reason will be described. The toner in the developing unit 323 normally deteriorates naturally when exposed to heat, moisture, and outside air, and also deteriorates due to friction with a conveying mechanism such as a developer conveying screw in the developing unit 323. Therefore, the toner in the developing unit 323 deteriorates with time and with the driving amount of the transport mechanism. The amount of charge of the toner in the developing unit 323 usually changes as the deterioration progresses. As described above, the charge amount of the toner in the developing unit 323 changes with time and the driving amount of the transport mechanism.

When the charge amount of the toner in the developing unit 323 changes, the toner amount attached to the photosensitive drum 321 changes if the photosensitive member charging potential remains the same, and a desired toner attachment amount cannot be realized. . Therefore, the photosensitive member charging potential V _S needs to be changed according to the charge amount of the toner in the developing unit 323. For this reason, the photosensitive member charging potential is determined according to the charge amount of the toner in the developing unit 323.

Here, the charging potential at the non-image portion of the photosensitive drum 321 after the toner image A is formed, that is, the photosensitive member charging potential after being uniformly charged by the charging unit 322 is defined as V _S , and the toner image The image portion on the surface of the photosensitive drum 321 after A is formed is A, the charging potential in the image portion A is _VA, and the transfer applied in the primary transfer region when the toner image A is transferred to the conveyance belt 311 If the bias is a V _T, as shown in FIG. 15, when the photosensitive drum charge potential V _S is varied, the transfer bias V _T also seen to vary in accordance with the variation.

With such transfer bias V _T in accordance with the photosensitive drum charge potential V _S varies, as shown in FIG. 15, the charge potential V _A at the image portion A is formed as the transfer bias V _T by the transfer bias V _T The electrostatic contrast ΔV _A ′, which is the potential difference between the two, also varies according to the variation. As a result, when the transfer bias V _T varies, as shown in FIG. 15, also transfer electric field strength [Delta] V _A at the image portion will vary depending on the variation. As described above, in the image forming apparatus 1 according to the present embodiment, the transfer electric field strength ΔV _A varies depending on the photosensitive member charging potential V _S. For these reasons, the transfer electric field strength varies in the image forming apparatus 1 according to the present embodiment.

When the transfer electric field intensity ΔV _A changes, as described with reference to FIG. 12, the amount of lubricant supplied to the photosensitive drum 321 also changes according to the change. For this reason, the image forming apparatus 1 according to the present embodiment controls the amount of the collected leakage toner according to the primary transfer rate, so that the amount of the lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C. Is configured to control. As a result, the image forming apparatus 1 according to the present embodiment can keep the amount of lubricant supplied to the photosensitive drum 321C by the lubricant application unit 326C within an appropriate range without being affected by the primary transfer rate. Become.

  Next, in the image forming apparatus 1 according to the present embodiment, a second factor that causes the transfer intensity to vary will be described with reference to FIG. FIG. 16 is a diagram showing how the transfer charge intensity varies according to the average image area ratio in the main scanning direction in the image forming apparatus 1 according to the present embodiment. In FIG. 16, the case where the toner image B is formed on the photosensitive drum 321 and the case where the toner image C is formed will be described.

The image portion on the surface of the photosensitive drum 321 after the toner image B is formed is B, the charging potential in the image portion B is V _B, and the image portion on the surface of the photosensitive drum 321 after the toner image C is formed is and the image portion C, and the charging potential of the image portion C and V _C, and a transfer bias applied at the primary transfer region and V _T, the average image area ratio in the main scanning direction of the image portion B and S _B, the image portion C If the average image area ratio S in the main scanning direction is S _C and S _B and S _C are not the same, as shown in FIG. 16, if the average image area ratio S in the main scanning direction fluctuates, the transfer bias V _T it can be seen that varies in accordance with the change.

  Here, the average image area ratio S in the main scanning direction will be described with reference to FIG. FIG. 17 is a diagram for explaining an average image area ratio in the main scanning direction in the image forming apparatus 1 according to the present embodiment.

As shown in FIG. 17, it is necessary to attach a toner to form an image on a transfer sheet per unit number of sheets, that is, a secondary of the photosensitive drum 321 when an image is formed on a transfer sheet per unit number. The total number of pixels in the scanning direction is M, and at the α-th pixel, the charged potential in the non-image portion of the photosensitive drum 321 after the toner image is formed, that is, after being uniformly charged by the charging unit 322. the photosensitive drum charge potential and V _S, the start position in the main scanning direction of the photosensitive drum 321 and L _1, the position of the end in the main scanning direction of the photosensitive drum 321 and L _2, the toner image is formed when the function representing the displacement in the main scanning direction of the charging potential of the image portion of the photosensitive drum 321 after f _alpha and (V), the average image area ratio S in the main scanning direction
Is calculated by

With such transfer bias V _T varies according to the average image area ratio S in the main scanning direction, as shown in FIG. 16, the transfer electric field intensity in the image portion, will also vary according to the variation. As described above, in the image forming apparatus 1 according to the present embodiment, the transfer electric field strength varies with the average image area ratio S in the main scanning direction. For these reasons, the transfer strength varies in the image forming apparatus 1 according to the present embodiment.

  When the transfer electric field strength varies, as described with reference to FIG. 12, the amount of lubricant supplied to the photosensitive drum 321 also varies according to the variation. For this reason, the image forming apparatus 1 according to the present embodiment controls the amount of the collected leakage toner according to the primary transfer rate, so that the amount of the lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C. Is configured to control. As a result, the image forming apparatus 1 according to the present embodiment can keep the amount of lubricant supplied to the photosensitive drum 321C by the lubricant application unit 326C within an appropriate range without being affected by the primary transfer rate. Become.

  In the present embodiment, as described with reference to FIG. 16, the example in which the transfer electric field intensity varies depending on the average image area ratio S in the main scanning direction has been described. However, the average image area ratio S in the main scanning direction is described. Since the pixel area ratio H varies in relation to the image area ratio H, the pixel area ratio H may be a factor that causes the transfer electric field intensity to vary instead of the average image area ratio S in the main scanning direction.

Here, the image area ratio H will be described. The total number of pixels corresponding to the image portion of the photosensitive drum 321 when an image is formed on the transfer paper per unit number of sheets, that is, the pixel that needs to be attached with toner to form an image on the transfer paper per unit number of sheets. (Hereinafter referred to as “the number of printing pixels”) is N, and when the total number of pixels corresponding to the non-image portion and pixels corresponding to the image portion on the photosensitive drum 321 is T, the image area ratio H Is
Is calculated by

In addition, the image area ratio H is
May be calculated by:

Therefore, the average image area ratio S in the main scanning direction is
It may be calculated by

  In addition, the average image area ratio S in the main scanning direction fluctuates in relation to the number N of printing pixels when forming an image on the transfer paper per unit number of sheets. Instead of this, the number N of printing pixels may be a factor that causes the transfer electric field intensity to fluctuate.

  Next, in the image forming apparatus 1 according to the present embodiment, the third factor that causes the transfer intensity to vary will be described with reference to FIG. FIG. 18 is a diagram illustrating how the transfer electric field strength varies according to the average image density in the main scanning direction in the image forming apparatus 1 according to the present embodiment. In FIG. 18, a case where the case where the toner image D is formed on the photosensitive drum 321 is compared with the case where the toner image E is formed will be described.

The image portion on the surface of the photosensitive drum 321 after the toner image D is formed is D, the charging potential in the image portion D is V _D, and the image portion on the surface of the photosensitive drum 321 after the toner image E is formed is and the image portion E, the charge potential of the image portion E and V _E, the transfer bias applied at the primary transfer region and V _T, the average image area ratio in the main scanning direction of the image portion D and S _D, the image portion E an average image area ratio in the main scanning direction and S _E, is identical to the S _D and S _E, the average image density in the main scanning direction of the image portion D and C _D, the average in the main scanning direction of the image portion E the image density and C _E, if the C _D and C _E were not the same, as shown in FIG. 18, when the average image density in the main scanning direction varies, and the S _D and S _E be the same also, also the transfer bias _{V T} It can be seen that varies in accordance with the change.

  Here, the average image density C in the main scanning direction will be described with reference to FIG. FIG. 19 is a diagram for explaining the average image density in the main scanning direction in the image forming apparatus 1 according to the present embodiment.

As shown in FIG. 19, it is necessary to attach a toner to form an image on a transfer sheet per unit number of sheets, that is, a sub drum of the photosensitive drum 321 when an image is formed on a transfer sheet per unit number of sheets. The total number of pixels in the scanning direction is M, and at the α-th pixel, the charged potential in the non-image portion of the photosensitive drum 321 after the toner image is formed, that is, after being uniformly charged by the charging unit 322. the photosensitive drum charge potential and V _S, the start position in the main scanning direction of the photosensitive drum 321 and L _1, the position of the end in the main scanning direction of the photosensitive drum 321 and L _2, the toner image is formed photoreceptor each application start position of the charging potential of the image portion and the application end position the sum of the distance in the main scanning direction and L _3, the toner image is of forming drum 321 after The function representing the displacement in the main scanning direction of the charging potential of the image portion of the photosensitive drum 321 when the f α _(V) after the average image density C in the main scanning direction,
Is calculated by

In addition, the average image density C in the main scanning direction is defined as each image on the photosensitive drum 321 after the toner image is formed at the α pixel, where M is the total number of pixels in the sub-scanning direction of the photosensitive drum 321. If the sum of the peak values of the charging potential at the part is R _α ,
It may be calculated by

With such transfer bias V _T varies according to the average image density C in the main scanning direction, as shown in FIG. 18, the transfer electric field intensity in the image portion, will also vary according to the variation. As described above, in the image forming apparatus 1 according to the present embodiment, the transfer electric field strength varies depending on the average image density C in the main scanning direction. For these reasons, the transfer strength varies in the image forming apparatus 1 according to the present embodiment.

  When the transfer electric field strength varies, as described with reference to FIG. 12, the amount of lubricant supplied to the photosensitive drum 321 also varies according to the variation. For this reason, the image forming apparatus 1 according to the present embodiment controls the amount of the collected leakage toner according to the primary transfer rate, so that the amount of the lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C. Is configured to control. As a result, the image forming apparatus 1 according to the present embodiment can keep the amount of lubricant supplied to the photosensitive drum 321C by the lubricant application unit 326C within an appropriate range without being affected by the primary transfer rate. Become.

In the present embodiment, as described with reference to FIG. 18, the example in which the transfer electric field intensity varies depending on the average image density C in the main scanning direction has been described, but the average image density C in the main scanning direction is Since it fluctuates in relation to the image density K, the image density K may be a factor that fluctuates the transfer electric field strength instead of the average image area ratio S in the main scanning direction. Here, the image density K is
Is calculated by

  As described above, the image forming apparatus 1 according to the present embodiment controls the amount of collected leakage toner using the fact that the amount of lubricant supplied to the photosensitive drum 321C varies depending on the amount of collected leakage toner. By doing so, the amount of lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C is controlled. In particular, in the image forming apparatus 1 according to the present embodiment, the amount of lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C is controlled by controlling the amount of the recovery leakage toner according to the primary transfer rate. Is controlled in accordance with the primary transfer rate. The gist of the image forming apparatus 1 according to the present embodiment is configured as described above.

  In other words, when the primary transfer rate is low, the image forming apparatus 1 according to the present embodiment controls the amount of the collected leakage toner to be small so that the lubricant supply unit 326C can transfer the surface of the photosensitive drum 321C. It is configured to prevent an excessive amount of lubricant from being supplied. As a result, the image forming apparatus 1 according to the present embodiment can apply an appropriate amount of lubricant to the surface of the photosensitive drum 321C even when the primary transfer rate is low.

  On the contrary, the image forming apparatus 1 according to the present embodiment controls the surface of the photosensitive drum 321C from the lubricant supply unit 326C by controlling the amount of the collected leakage toner to be increased when the primary transfer rate is high. It is configured to prevent the amount of lubricant supplied to the battery from becoming too small. As a result, the image forming apparatus 1 according to the present embodiment can apply an appropriate amount of lubricant to the surface of the photosensitive drum 321C even when the primary transfer rate is high.

  As described above, the image forming apparatus 1 according to the present embodiment controls the amount of the recovery-leaked toner according to the primary transfer rate, so that the lubricant supplied from the lubricant application unit 326C to the surface of the photosensitive drum 321C can be obtained. Configured to control the amount. As a result, the image forming apparatus 1 according to the present embodiment can keep the amount of lubricant supplied to the photosensitive drum 321C by the lubricant application unit 326C within an appropriate range without being affected by the primary transfer rate. Become.

  Note that the image forming apparatus 1 according to the present embodiment has been described with respect to the example in which the amount of lubricant supplied to the surface of the photosensitive drum 321 is controlled according to the primary transfer rate. In addition, the image forming apparatus 1 according to the present embodiment further controls the amount of lubricant supplied to the surface of the photosensitive drum 321 according to the driving amount of the photosensitive drum 321 in addition to this. It may be configured. Here, the driving amount of the photosensitive drum 321 includes the rotational speed, the circumferential distance, the driving time, and the like of the photosensitive drum 321.

  As described above, the reason why the image forming apparatus 1 according to this embodiment controls the amount of the lubricant supplied to the surface of the photosensitive drum 321 according to the driving amount of the photosensitive drum 321 is that the driving amount of the photosensitive drum 321. This is because the wear of the contact portion of the edge portion of the cleaning blade 325a with the photosensitive drum 321 changes accordingly. If the wear of the contact portion changes according to the driving amount of the photosensitive drum 321, the amount of the recovery leakage toner changes, and as a result, the lubricant application unit 326 supplies the surface of the photosensitive drum 321. This is because the amount of lubricant changes. That is, as the driving amount of the photosensitive drum 321 increases, the contact portion wears, and the amount of toner that passes between the cleaning blade 325a and the photosensitive drum 321 increases. Therefore, at any primary transfer rate from the beginning. This is because the contact pressure needs to be increased.

  Specifically, in the image forming apparatus 1 according to the present embodiment, as the drive amount of the photosensitive drum 321 increases, the wear of the contact portion tends to increase, and the amount of collected leakage toner tends to increase. This is because the amount of lubricant supplied to the surface of the photosensitive drum 321 by the lubricant application unit 326 tends to increase. On the other hand, in the image forming apparatus 1 according to the present embodiment, the smaller the drive amount of the photosensitive drum 321, the smaller the wear of the contact portion tends to decrease, and the amount of collected leakage toner tends to decrease. This is because the amount of lubricant supplied to the surface of the photosensitive drum 321 by the coating unit 326 tends to decrease.

  Therefore, the image forming apparatus 1 according to the present embodiment performs control so that the amount of lubricant supplied to the surface of the photosensitive drum 321 decreases as the driving amount of the photosensitive drum 321 increases. Even if the wear of the contact portion increases due to an increase in the driving amount of 321, an excessive amount of lubricant is prevented from being supplied to the surface of the photosensitive drum 321, and an appropriate amount of lubricant is applied to the surface of the photosensitive drum 321. It becomes possible to apply.

  On the contrary, the image forming apparatus 1 according to the present embodiment controls the photosensitive drum so that the amount of lubricant supplied to the surface of the photosensitive drum 321 with a small driving amount of the photosensitive drum 321 increases. Even when the driving amount of 321 is small and the wear of the contact portion is small, the amount of lubricant supplied to the surface of the photosensitive drum 321 is prevented from becoming excessive, and an appropriate amount of lubricant is applied to the surface of the photosensitive drum 321. It becomes possible to apply to.

  As described above, the image forming apparatus 1 according to the present embodiment controls the amount of lubricant supplied to the photosensitive drum 321 according to the driving amount of the photosensitive drum 321, so that the driving amount does not matter. It becomes possible to keep the amount of lubricant supplied to the photosensitive drum 321 within an appropriate range regardless of the primary transfer rate.

  Further, the image forming apparatus 1 according to the present embodiment has been described with respect to the example in which the amount of lubricant supplied to the surface of the photosensitive drum 321 is controlled according to the primary transfer rate. In addition to this, the image forming apparatus 1 according to the present embodiment is further configured to vary the control amount of the lubricant supply amount to the photosensitive drum 321 in accordance with the driving amount of the photosensitive drum 321. May be.

  As described above, the reason why the image forming apparatus 1 according to this embodiment varies the control amount of the lubricant supply amount to the photosensitive drum 321 according to the driving amount of the photosensitive drum 321 is based on the driving amount of the photosensitive drum 321. This is because the wear of the contact portion of the edge portion of the cleaning blade 325a with the photosensitive drum 321 changes accordingly. When the wear of the contact portion changes according to the driving amount of the photosensitive drum 321, the amount of change in the amount of collected leakage toner due to the change in the primary transfer rate fluctuates. As a result, the surface of the photosensitive drum 321 is changed. This is because the amount of change due to the change in the primary transfer rate of the supplied lubricant changes. That is, as the driving amount of the photosensitive drum 321 increases, the contact portion wears, and the amount of toner that passes between the cleaning blade 325a and the photosensitive drum 321C increases. Therefore, the photosensitive drum 321 corresponding to the primary transfer rate. This is because it is necessary to reduce the control amount of the lubricant supply amount to the motor.

  Specifically, in the image forming apparatus 1 according to the present embodiment, the larger the drive amount of the photosensitive drum 321, the greater the wear of the contact portion, and the amount of change in the amount of collected leakage toner due to fluctuations in the primary transfer rate. This is because the amount of change in the amount of lubricant supplied to the photosensitive drum 321 according to the primary transfer rate tends to decrease. On the other hand, in the image forming apparatus 1 according to the present embodiment, as the driving amount of the photosensitive drum 321 decreases, the wear of the contact portion decreases, and the amount of change in the amount of collected leakage toner due to fluctuations in the primary transfer rate tends to increase. As a result, the amount of change in the amount of lubricant supplied to the photosensitive drum 321 according to the primary transfer rate tends to increase.

  Therefore, the image forming apparatus 1 according to the present embodiment performs control so that the control amount of the lubricant supply amount to the photoconductive drum 321 is decreased as the drive amount of the photoconductive drum 321 is increased. Even if the wear of the contact portion increases due to an increase in the driving amount of 321, the amount of lubricant supplied to the photosensitive drum 321 is prevented from becoming excessive, and an appropriate amount of lubricant is applied to the surface of the photosensitive drum 321. It becomes possible to apply to.

  On the contrary, the image forming apparatus 1 according to the present embodiment performs control so that the control amount of the lubricant supply amount to the photoconductive drum 321 increases as the drive amount of the photoconductive drum 321 decreases. Even when the driving amount of the drum 321 is small and the wear of the contact portion is small, the amount of lubricant supplied to the photosensitive drum 321 is prevented from being excessive, and an appropriate amount of lubricant is applied to the surface of the photosensitive drum 321. It becomes possible to apply to.

  As described above, the image forming apparatus 1 according to the present embodiment varies the control amount of the lubricant supply amount to the photosensitive drum 321 according to the driving amount of the photosensitive drum 321 according to the driving amount of the photosensitive drum 321. By doing so, it becomes possible to keep the amount of lubricant supplied to the photosensitive drum 321 within a proper range regardless of the primary transfer rate, regardless of the amount of drive.

  In the image forming apparatus 1 according to the present embodiment, the example in which the movement of the cleaning blade 325a is controlled by controlling the rotation of the cleaning blade position control roller 325d has been described. However, the movement of the cleaning blade 325a is controlled. Any configuration is possible as long as the configuration can be used.

  In the image forming apparatus 1 according to the present embodiment, the example in which the contact pressure of the cleaning blade 325a on the surface of the photosensitive drum 321C is controlled by controlling the rotation of the cleaning blade position control roller 325d has been described. For example, any configuration is possible as long as the contact pressure can be controlled by moving the photosensitive drum 321C.

  In the image forming apparatus 1 according to the present embodiment, the photosensitive drum of the cleaning blade 325a is used to control the amount of lubricant supplied from the lubricant application unit 326 to the surface of the photosensitive drum 321 per unit time. The example configured to control the contact pressure on the surface of 321 has been described. In addition, the image forming apparatus 1 according to the present embodiment is configured to control the lubricant supply amount per unit time to the surface of the photosensitive drum 321 by controlling the rotation speed of the lubricant application roller 326b. May be. That is, the image forming apparatus 1 according to the present embodiment increases the amount of lubricant supplied per unit time to the surface of the photosensitive drum 321 by increasing the rotational speed of the lubricant application roller 326b, and conversely, the rotation thereof. It may be configured to decrease by decreasing the speed.

  This is because the amount of lubricant supplied to the surface of the photosensitive drum 321 per unit time increases as the rotational speed of the lubricant application roller 326b increases as shown in FIG. FIG. 20 is a diagram showing the relationship between the rotational speed of the lubricant application roller 326b and the amount of lubricant supplied to the photosensitive drum 321 according to this embodiment.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Transfer paper 10 CPU
20 RAM
30 ROM
40 HDD
50 I / F
DESCRIPTION OF SYMBOLS 60 Display part 70 Operation part 80 Dedicated device 90 Bus 110 Main control part 120 Engine control part 130 Image processing part 140 Operation display control part 150 Input / output control part 200 Paper feed table 210 Paper feed roller 220 Separation roller pair 230 Registration roller pair 300 Print engine 310 Non-birth conveying means 311 Conveying belt 312 Driving roller 313 Driven roller 314 First tension roller 315 Second tension roller 320 Image forming unit 321 Photosensitive drum 322 Charging unit 322a Charging roller 322b Charging roller cleaner 323 Developing unit 323a First developer conveying screw 323b Second developer conveying screw 323c Developing roller 324 Charger 325 Toner recovery unit 325a Cleaning blade 325 b Collected toner conveying screw 325c Collected toner conveying path 325d Cleaning blade position control roller 326 Lubricant application unit 326a Solid lubricant 326b Lubricant application roller 326c Solid lubricant pressing spring 327 Lubricant equalizing blade 330 Optical writing device 340 Primary transfer roller 350 Toner bottle 360 Secondary transfer roller 370 Fixing unit 371 Fixing roller pair 380 Belt cleaner 400 Print output tray 410 Output roller pair 500 ADF
600 Scanner engine 700 Output tray for scanning 800 Display panel 900 Network I / F

JP 2010-133997 A

Claims (10)

Lubricant supply amount control device for controlling the amount of lubricant supplied by a lubricant supply unit that supplies lubricant to the surface of an image carrier that electrostatically carries a developer image composed of a charged developer. Because
Among the developers constituting the developer image carried on the image carrier, the developer constituting the developer image carried on the image carrier is electrostatically A transfer rate estimator for estimating a ratio of the amount of developer transferred from the image carrier when transferring the developer image by moving;
According to the estimated ratio, a lubricant supply amount control unit that controls the supply amount of the lubricant per unit time to the surface of the image carrier by the lubricant supply unit;
A lubricant supply amount control device comprising:   The lubricant supply amount control unit is applied to transfer the developer image by electrostatically moving the developer constituting the developer image carried on the image carrier. The supply amount of the lubricant per unit time to the surface of the image carrier by the lubricant supply unit is controlled according to the strength of the transfer electric field formed by the transfer voltage applied. 2. The lubricant supply amount control device according to 1.   The lubricant supply amount control unit is configured to control the lubricant according to a charge amount of the developer stored in a developer storage unit for storing the developer supplied to the image carrier. 3. The lubricant supply amount control device according to claim 1, wherein the supply amount of the lubricant per unit time to the surface of the image carrier by the supply unit is controlled.   The lubricant supply amount control unit is configured to apply the lubrication per unit time to the surface of the image carrier by the lubricant supply unit in accordance with a charging voltage applied to uniformly charge the image carrier. 4. The lubricant supply amount control device according to claim 1, wherein the supply amount of the lubricant is controlled.   The lubricant supply amount control unit applies the lubricant supply unit to the surface of the image carrier according to the amount of the developer constituting the developer image carried on the image carrier. The lubricant supply amount control device according to any one of claims 1 to 4, wherein the lubricant supply amount per unit time is controlled.   The lubricant supply amount control unit includes the lubricant per unit time applied to the surface of the image carrier by the lubricant supplier according to the area of the developer image carried on the image carrier. The lubricant supply amount control device according to any one of claims 1 to 5, wherein the supply amount of the lubricant is controlled.   The lubricant supply amount control unit includes the lubricant per unit time applied to the surface of the image carrier by the lubricant supplier according to the density of the developer image carried on the image carrier. The supply amount control device for a lubricant according to any one of claims 1 to 6, wherein the supply amount of the lubricant is controlled.   The lubricant supply amount control unit controls the supply amount of the lubricant per unit time to the surface of the image carrier by the lubricant supply unit according to the drive amount of the image carrier. The lubricant supply amount control device according to any one of claims 1 to 7.   The lubricant supply amount control unit removes the developer remaining on the surface of the image carrier after the developer image is transferred by contacting the surface of the rotating image carrier. By controlling the contact pressure of the developer removing unit to the surface of the image carrier, the amount of lubricant supplied to the surface of the image carrier by the lubricant supply unit per unit time is controlled. The lubricant supply amount control device according to any one of claims 1 to 8, wherein   The lubricant supply amount control unit rotates the lubricant while contacting the rotating image carrier with an axis parallel to the rotating axis of the rotating image carrier as a rotation axis. The amount of the lubricant supplied per unit time to the surface of the image carrier by the lubricant supply unit is controlled by controlling the rotation speed of the lubricant supply unit supplied to the surface. The lubricant supply amount control device according to any one of claims 1 to 9.