JP2017156535A - Toner supply device and image forming apparatus - Google Patents

Abstract

To stabilize the amount of toner supplied to a developing device even when the conveyance efficiency of a conveyance unit that conveys toner supplied to the developing device fluctuates. A toner supply device includes a DC motor 60 with a brush, a conveyance member, a target rotation amount setting unit 83, a rotation amount detection unit, a conveyance control unit 84, and an actual speed index value deriving unit 82. Prepare. The actual speed index value deriving unit 82 derives an actual speed index value corresponding to the actual rotation speed of the transport member. The target rotation amount setting unit 83 has a rotation speed at which the actual speed index value is faster than the reference rotation speed than the target rotation amount when the actual speed index value represents a preset reference rotation speed. Is set to a large value. [Selection] Figure 5

Description

  The present invention relates to a toner supply device and an image forming apparatus.

  In general, an electrophotographic image forming apparatus includes a toner supply device that supplies toner to a developing device. The toner supply device includes a screw-type transport unit having a shaft part and a blade part projecting spirally outward from the shaft part. The conveyance unit conveys the toner to an outlet of the storage unit by rotating in a storage unit that stores the toner. The toner is supplied from the outlet of the storage unit to the developing device.

  Further, it is known that the image forming apparatus includes means for detecting the rotation amount of the conveyance unit, and controls the operation of the conveyance unit so that the detected rotation amount matches a target rotation amount. (For example, refer to Patent Document 1).

JP2011-197229A

  By the way, the toner transport efficiency by the transport unit, that is, the toner transport amount per unit rotation amount by the transport unit varies depending on the state of the toner. For example, under a situation where the fluidity of the toner in the storage unit is high, the toner bulk density is small, and the toner transport efficiency by the transport unit deteriorates. Further, when the amount of the toner in the storage unit is too small, the toner transport efficiency by the transport unit deteriorates.

  When the toner transport efficiency by the transport unit fluctuates, the toner supply amount to the developing device becomes unstable, which causes image quality deterioration.

  An object of the present invention is to provide a toner supply device and an image forming apparatus that can stabilize the amount of toner supplied to a developing device even when the conveyance efficiency of a conveyance unit that conveys toner supplied to the developing device varies. It is to provide.

  A toner supply device according to one aspect of the present invention is a device that supplies toner to a developing device, and includes a DC motor with a brush, a conveyance member, a target rotation amount setting unit, a rotation amount detection unit, and conveyance control. And an actual speed index value deriving unit. The conveying member includes a shaft portion and a blade portion projecting spirally outward from the shaft portion. The transport member is rotationally driven by the DC motor. The conveyance unit conveys the toner to an outlet of the storage unit that communicates with the developing device by rotating in a predetermined positive rotation direction in a storage unit that stores the toner. The target rotation amount setting unit sets a target rotation amount of the transport member. The rotation amount detection unit detects an actual rotation amount of the transport member. The conveyance control unit operates the DC motor until the actual rotation amount reaches the target rotation amount. The actual speed index value deriving unit corresponds to the actual rotation speed of the transport member by detecting the time required for the rotation of the unit rotation amount of the transport member or the actual rotation amount per unit time of the transport member. The actual speed index value to be derived is derived. The target rotation amount setting unit is a rotation speed at which the actual speed index value is faster than the reference rotation speed than the target rotation amount when the actual speed index value represents a preset reference rotation speed. Is set to a large value.

  An image forming apparatus according to another aspect of the present invention includes the toner supply device and a developing device to which toner is supplied from the toner supply device.

  According to the present invention, a toner supply device and an image forming apparatus that can stabilize the amount of toner supplied to a developing device even when the conveyance efficiency of a conveyance unit that conveys toner supplied to the developing device varies. It becomes possible to provide.

FIG. 1 is a configuration diagram of an image forming apparatus including a toner supply device according to the embodiment. FIG. 2 is a configuration diagram of the developing device. FIG. 3 is a configuration diagram of the toner supply device according to the embodiment. FIG. 4 is a perspective view of a pulse rotator provided in the toner supply device according to the embodiment. FIG. 5 is a block diagram of a control-related unit in the toner supply apparatus according to the embodiment. FIG. 6 is a flowchart illustrating an example of a procedure of toner conveyance control in the toner supply device according to the embodiment. FIG. 7 is a flowchart illustrating an example of a procedure of alarm processing in the toner supply device according to the embodiment. FIG. 8 is a flowchart illustrating an example of a procedure of toner supply control in the toner supply device according to the embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the following embodiment is an example which actualized this invention, Comprising: It does not have the character which limits the technical scope of this invention.

[Configuration of Image Forming Apparatus 10]
First, the configuration of an image forming apparatus 10 including a toner supply device 5 according to the embodiment will be described with reference to FIG.

  The image forming apparatus 10 is an apparatus that forms an image on a sheet by using an electrophotographic method using the developer 9. The sheet is a sheet-like image forming medium such as paper and an envelope. Developer 9 is a two-component developer including toner 9a and carrier 9b. The carrier 9b is a granular material having magnetism.

  The image forming apparatus 10 includes a sheet supply unit 2, a sheet conveying unit 3, an image forming unit 40, a toner supply device 5, a control unit 8, a display unit 80, and the like. The image forming unit 40 includes an image forming unit 4, an optical scanning unit 46, a fixing device 49, and the like.

  In the sheet supply unit 2, the pickup unit 22 sends out the sheets one by one from the sheet cassette 21 that stores a plurality of the sheets to the conveyance path 30. Further, the sheet conveyance unit 3 conveys the sheet along the conveyance path 30, and discharges the sheet on which the image is formed from the conveyance path 30 onto the discharge tray 101.

  The image forming unit 4 performs development processing and primary transfer processing using a powdery developer 9. An image forming apparatus 10 shown in FIG. 1 is a tandem image forming apparatus and a color printer. Therefore, the image forming apparatus 10 includes a plurality of image forming units 4 corresponding to each color of cyan, magenta, yellow, and black, an intermediate transfer belt 47, a secondary transfer device 48, and a secondary cleaning device 470.

  Each of the image forming units 4 includes a photoreceptor 41, a charging device 42, a developing device 43, a primary transfer device 44, a primary cleaning device 45, and the like.

  In each image forming unit 4, the drum-shaped photoconductor 41 rotates, and the charging device 42 charges the surface of the photoconductor 41 uniformly. The optical scanning unit 46 writes an electrostatic latent image on the surface of the photoconductor 41 by scanning with laser light.

  The developing device 43 uses the two-component developer 9 to develop the electrostatic latent image on the photoreceptor 41 as an image of the toner 9a. The toner supply device 5 is provided for each color of the toner 9 a and supplies the toner 9 a to the developing device 43. The toner 9 a is supplied from the toner supply device 5 to the developing device 43.

  The primary transfer device 44 transfers the image of the toner 9 a on the surface of the photoreceptor 41 to the intermediate transfer belt 47. The primary cleaning device 45 removes the toner 9 a remaining on the surface of the photoreceptor 41.

  The secondary transfer device 48 transfers the toner image formed on the intermediate transfer belt 47 to the sheet in the conveyance path 30. The secondary cleaning device 470 removes the toner 9a remaining on the intermediate transfer belt 47.

  The primary transfer device 44, the intermediate transfer belt 47, and the secondary transfer device 48 constitute a transfer device that transfers the toner image on the photoreceptor 41 to the sheet.

  The fixing device 49 heats the toner image transferred to the sheet and fixes the toner image on the sheet. The fixing device 49 includes a fixing roller that rotates in contact with the toner image formed on the sheet, and a heater that heats the fixing roller.

[Configuration of Developing Device 43]
The developing device 43 shown in FIG. 2 is a so-called interactive touch-down developing device.

  The developing device 43 includes a developing tank 43x that stores the developer 9, and a developing roller 430, a magnetic roller 431, a magnet 432, a stirring screw 433, and a blade 434 that rotate in the developing tank 43x. The stirring screw 433 circulates and conveys the developer 9 in the developing tank 43x while stirring. The toner 9a is charged by being stirred.

  The magnetic roller 431 carries the two-component developer 9 on its outer peripheral surface. The magnetic roller 431 supplies the toner 9 a of the carried developer 9 to the developing roller 430.

  The magnetic roller 431 carries the developer 9 by the magnetic force of the magnet 432 included therein. The blade 434 limits the layer thickness of the developer 9 carried by the magnetic roller 431.

  The developing roller 430 carries the toner 9a supplied from the magnetic roller 431 on the outer peripheral surface. Further, the developing roller 430 supplies the toner 9 a to the portion of the electrostatic latent image on the surface of the photoreceptor 41. As a result, the developing roller 430 develops the electrostatic latent image as the toner image.

  Further, the developing device 43 includes a magnetic permeability sensor 435 that detects the magnetic permeability of the developer 9 in the developing tank 43x. A large magnetic permeability detected by the magnetic permeability sensor 435 indicates that the ratio of the carrier 9b in the developer 9 is high, that is, the amount of the toner 9a in the developing tank 43x is small. In the following description, the magnetic permeability detected by the magnetic permeability sensor 435 is referred to as detected magnetic permeability.

[Toner supply device 5]
As shown in FIG. 3, the toner supply device 5 includes a toner supply device 50 and a toner transport device 6.

  The toner supply device 50 includes a toner container 51, a supply screw 52, a gear mechanism 54, a supply motor 53, and the like. In FIG. 3, the gear mechanism 54 is schematically shown by a virtual line. The toner container 51 is detachably attached to the main body of the image forming apparatus 10.

  The toner conveyance device 6 includes a conveyance motor 60, an intermediate storage unit 61, a conveyance screw 62, a gear mechanism 63, a pulse generation unit 64, a toner level sensor 66, and the like.

  The replenishment screw 52 rotates in the toner container 51 that stores the toner 9 a, thereby sending the toner 9 a from the outlet 51 a of the toner container 51 into the intermediate storage unit 61. The supply motor 53 rotates the supply screw 52 via the gear mechanism 54. The replenishment screw 52 is an example of a delivery unit.

  The intermediate reservoir 61 is a hollow member that communicates with the toner container 51 and the developing tank 43x. The intermediate storage unit 61 temporarily stores the toner 9a. The intermediate storage unit 61 is an example of a storage unit that stores the toner 9a.

  The inlet 61a of the intermediate reservoir 61 communicates with the outlet 51a of the toner container 51, and the outlet 61b of the intermediate reservoir 61 communicates with the inlet 43y of the developing tank 43x via the vertical duct 65.

  The conveying screw 62 is a screw-type conveying portion having a shaft portion 62a and a blade portion 62b projecting spirally outward from the shaft portion 62a. The conveying screw 62 is rotatably supported by a bearing portion 61 c formed in the intermediate storage portion 61.

  The transport screw 62 is rotationally driven by the transport motor 60. The agitating screw 433 and the replenishing screw 52 also have the same structure as the conveying screw 62.

  The conveying screw 62 conveys the toner 9a to the outlet 61b of the intermediate reservoir 61 that communicates with the developing tank 43x of the developing device 43 by rotating in a predetermined forward rotation direction in the intermediate reservoir 61. The conveying screw 62 is an example of a conveying member.

  The transport screw 62 transports the toner 9a in the lateral direction in the intermediate reservoir 61. In the example shown in FIG. 3, the conveying screw 62 conveys the toner 9a in the horizontal direction.

  The transport motor 60 rotationally drives the transport screw 62 via the gear mechanism 63. The conveyance motor 60 is a DC motor with a brush. Therefore, the rotation speed of the transport motor 60 varies depending on the load.

  The pulse generator 64 generates a pulse signal each time the conveying screw 62 rotates by a predetermined unit angle. The pulse generator 64 includes a pulse rotator 641 and a photosensor 642.

  The pulse rotator 641 is a member that rotates in conjunction with the conveying screw 62. In the example shown in FIG. 3, the pulse rotating body 641 is coaxially connected to the shaft portion 62 a of the conveying screw 62.

  It is also conceivable that the pulse rotating body 641 is connected to the shaft portion 62a of the conveying screw 62 via a gear mechanism, a link mechanism, a pulley mechanism, or the like. Also in this case, the pulse rotator 641 rotates in conjunction with the transport screw 62.

  As shown in FIGS. 3 and 4, the pulse rotator 641 includes a detected portion 641 a in which a plurality of openings 641 b are formed. In the present embodiment, the detected portion 641a is a cylindrical portion with the rotation center of the pulse rotator 641 as the center.

  The plurality of openings 641b are formed at equal intervals along a circle centered on the rotation center of the pulse rotator 641. In the example shown in FIGS. 3 and 4, the plurality of openings 641 b are formed in a slit shape parallel to the rotation center line of the pulse rotator 641.

  The photosensor 642 detects that each of the plurality of openings 641b in the rotating detection target part 641a or a portion between the plurality of openings 641b passes a predetermined detection position. In the present embodiment, the photosensor 642 is a transmissive photosensor, and outputs a pulse signal when each of the plurality of openings 641b passes through the detection position.

  Note that the photosensor 642 may be a reflective photosensor that outputs a pulse signal when each of the portions between the plurality of openings 641b passes through the detection position.

  As will be described later, the control unit 8 includes a pulse count unit 81 that counts the number of occurrences of the pulse signal output from the photosensor 642 and derives the count result as the actual rotation amount of the conveying screw 62 (FIGS. 1 and 5). reference).

  The pulse rotator 641, the photo sensor 642, and the pulse count unit 81 constitute an example of a rotation amount detection unit that detects the actual rotation amount of the transport screw 62.

  As will be described later, the conveyance control unit 84 of the control unit 8 controls the operation of the conveyance screw 62 until the actual rotation amount detected by the rotation amount detection unit reaches a target rotation amount described later, that is, a conveyance motor. Control for operating 60 is executed (see FIG. 5).

  The toner level sensor 66 is a sensor that detects whether or not the level of the toner 9a in the intermediate reservoir 61 is equal to or higher than a predetermined allowable lower limit level.

  For example, it is conceivable that a transmission window 61d which is a transparent partition wall portion is formed at the position of the allowable lower limit level in the intermediate storage portion 61. In this case, it is conceivable that the toner level sensor 66 is a transmissive photosensor that detects whether or not the toner 9a is present inside the transmissive window 61d.

  The control unit 8 controls electrical equipment in the image forming apparatus 10. The control unit 8 is also a part of the toner supply device 5. For example, the control unit 8 may be configured by an MPU (microprocessor unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), or the like.

  The display unit 80 is a device that displays information. For example, the display unit 80 may be a display panel such as a liquid crystal panel.

  Incidentally, the conveyance efficiency of the toner 9 a by the conveyance screw 62, that is, the conveyance amount of the toner 9 a per unit rotation amount by the conveyance screw 62 varies depending on the state of the toner 9 a in the intermediate storage unit 61. For example, under a situation where the fluidity of the toner 9a in the intermediate storage unit 61 is high, the bulk density of the toner 9a is small, so that the transport efficiency of the toner 9a by the transport screw 62 is deteriorated. Further, when the amount of the toner 9a in the intermediate storage unit 61 is too small, the conveyance efficiency of the toner 9a by the conveyance screw 62 is deteriorated.

  When the conveyance efficiency of the toner 9a by the conveyance screw 62 varies, the supply amount of the toner 9a to the developing device 43 becomes unstable, which causes deterioration in image quality.

  On the other hand, the toner supply device 5 has a function of stabilizing the supply amount of the toner 9a to the developing device 43 even when the transport efficiency of the transport screw 62 that transports the toner 9a supplied to the developing device 43 varies. The function will be described below.

[Configuration of control-related parts]
As shown in FIG. 5, the control unit 8 includes a pulse count unit 81, a pulse interval timing unit 82, a target rotation amount setting unit 83, a conveyance control unit 84, an alarm control unit 85, a replenishment control unit 86, and a data storage unit 87. Etc.

  As described above, the pulse count unit 81 derives the actual rotation amount of the conveying screw 62 by counting the number of generated pulse signals.

  The pulse interval timing unit 82 derives a detection pulse interval Tp corresponding to the actual rotational speed of the conveying screw 62 by measuring the time required for generating the predetermined number of pulse signals. Further, the pulse interval timer unit 82 records the latest detection pulse interval Tp in the data storage unit 87.

  For example, the pulse interval timing unit 82 derives the detection pulse interval Tp every time one image forming job is executed or every time an image forming process for one page is executed.

  The detection pulse interval Tp is inversely proportional to the actual rotational speed of the conveying screw 62. Therefore, the state where the detection pulse interval Tp is large is a state where the actual rotation speed of the conveying screw 62 is low. The detection pulse interval Tp is an example of an actual speed index value that is an index value of the actual rotation speed of the conveying screw 62.

  For example, the pulse interval timing unit 82 derives an average value of the time required for generating a plurality of predetermined pulse signals as the detection pulse interval Tp.

  The pulse generator 64 and the pulse interval timer 82 are an example of an actual speed index value deriving section that derives the actual speed index value by detecting the time required for the rotation of the unit rotation amount of the conveying screw 62. .

  In the present embodiment, the unit rotation amount is the rotation amount of the conveying screw 62 from the generation of one pulse signal to the generation of the next pulse signal.

  The target rotation amount setting unit 83 sets a target rotation amount of the conveying screw 62. In the present embodiment, the target rotation amount is a target pulse number representing the target generation number of the pulse signal. A method for setting the target rotation amount will be described later.

  The conveyance control unit 84 controls the operation of the conveyance screw 62 by controlling the conveyance motor 60. The supply controller 86 controls the operation of the supply screw 52 by controlling the supply motor 53. The replenishment control unit 86 is an example of a sending control unit that controls the operation of the sending unit.

  The alarm control unit 85 executes an alarm process for outputting an alarm message to the display unit 80. The data storage unit 87 is a computer-readable non-volatile memory.

[Toner transport control]
Next, an example of a procedure of toner conveyance control in the toner supply device 5 will be described with reference to a flowchart shown in FIG. The toner conveyance control is executed, for example, every time one image forming job is executed or every time an image forming process for one page is executed. In the following description, S101, S102,... Represent identification codes of steps executed by the control unit 8.

<Step S101>
First, the target rotation amount setting unit 83 determines whether or not the detection pulse interval Tp recorded in the data storage unit 87 is out of the reference range from the preset reference lower limit interval Tsmin to the reference upper limit interval Tsmax. .

  The reference lower limit interval Tsmin corresponds to the upper limit of the preset reference rotation speed range of the conveying screw 62, and the reference upper limit interval Tsmax corresponds to the lower limit of the reference rotation speed range.

<Step S102>
When it is determined in step S101 that the detection pulse interval Tp is out of the reference range, the target rotation amount setting unit 83 corrects a preset reference coefficient according to the detection pulse interval Tp, and the corrected Set the coefficient as the efficiency coefficient.

  The efficiency coefficient is a coefficient representing the efficiency of transporting the toner 9 a by the transport screw 62. For example, it is conceivable that the efficiency coefficient is a value obtained by converting the transport amount of the toner 9a per unit rotation amount by the transport screw 62 into the number of pixels.

  In the above case, the efficiency coefficient corresponds to the number of pixels that can be developed by the amount of toner 9a supplied to the developing device 43 when the conveying screw 62 rotates by the unit rotation amount. The efficiency coefficient may vary depending on the status of the toner 9a in the intermediate storage unit 61.

  The reference coefficient is a preset reference value of the efficiency coefficient. The reference coefficient represents the conveyance efficiency of the toner 9a by the conveyance screw 62 when the condition of the toner 9a in the intermediate storage unit 61 is a standard condition.

  When the detection pulse interval Tp is larger than the reference upper limit interval Tsmax, the toner 9a in the intermediate reservoir 61 has a high bulk density or the amount of toner 9a in the intermediate reservoir 61 is large. In this state, a relatively large load is applied to the motor 60. In such a state, generally, the conveyance efficiency of the toner 9a by the conveyance screw 62 is higher than usual.

  Therefore, when the detection pulse interval Tp is larger than the reference upper limit interval Tsmax, the target rotation amount setting unit 83 adds the addition coefficient corresponding to the difference between the detection pulse interval Tp and the reference upper limit interval Tsmax to the reference coefficient. Is set as the efficiency factor.

  The state in which the detection pulse interval Tp is larger than the reference upper limit interval Tsmax is a state in which the detection pulse interval Tp represents a rotational speed that is slower than the range of the reference rotational speed.

  On the other hand, the state in which the detection pulse interval Tp is smaller than the reference lower limit interval Tsmin is caused by the state in which the bulk density of the toner 9a in the intermediate reservoir 61 is small or the amount of the toner 9a in the intermediate reservoir 61 is small. Thus, the load applied to the transport motor 60 is small. In such a state, generally, the conveying effect of the toner 9a by the conveying screw 62 is deteriorated.

  Therefore, when the detection pulse interval Tp is smaller than the reference lower limit interval Tsmin, the target rotation amount setting unit 83 subtracts a subtraction coefficient corresponding to the difference between the reference lower limit interval Tsmin and the detection pulse interval Tp from the reference coefficient. Is set as the efficiency factor.

  The state in which the detection pulse interval Tp is smaller than the reference lower limit interval Tsmin is a state in which the detection pulse interval Tp represents a rotational speed that is faster than the reference rotational speed range.

  The correction value of the reference coefficient corresponding to the difference between each of the reference upper limit interval Tsmax and the reference lower limit interval Tsmin and the detection pulse interval Tp is obtained by a preliminary evaluation experiment.

<Step S103>
On the other hand, when it is determined in step S101 that the detection pulse interval Tp is not out of the reference range, the target rotation amount setting unit 83 sets the reference coefficient as the efficiency coefficient.

<Step S104>
Next, the target rotation amount setting unit 83 sets the target rotation amount based on the efficiency coefficient set in step S102 or step S103. The target rotation amount is the rotation amount of the conveying screw 62 necessary for supplying the developing device 43 with the amount of toner 9a consumed in the developing device 43.

  In the present embodiment, the target rotation amount setting unit 83 calculates the target rotation amount by dividing the integrated value of the number of effective pixels in the image to be developed by the developing device 43 by the efficiency coefficient. The effective pixel number is the number of pixels developed by the toner 9a. For example, it is conceivable that the target rotation amount setting unit 83 calculates the integrated value of the effective pixels based on a so-called printing rate.

  That is, when the detection pulse interval Tp is out of the reference range, the target rotation amount setting unit 83 corrects the reference coefficient according to the detection pulse interval Tp (S102), and further, the integrated value of the effective pixels And a rotation amount calculated according to the corrected efficiency coefficient is set as the target rotation amount.

  Further, the target rotation amount setting unit 83 sets the standard target rotation amount as the target rotation amount when the detected magnetic permeability is between a predetermined allowable lower limit and an allowable upper limit.

  Further, the target rotation amount setting unit 83 corrects the increase with respect to the reference target rotation amount when the detected magnetic permeability exceeds the allowable upper limit, and sets the corrected rotation amount as the target rotation amount. .

  On the other hand, when the detected magnetic permeability is less than the allowable lower limit, the target rotation amount setting unit 83 sets the target rotation amount to zero until the detected magnetic permeability falls within a predetermined appropriate range.

<Step S105>
Next, the conveyance control unit 84 rotates the conveyance motor 60 in the normal direction to rotate the conveyance screw 62 in the normal rotation direction.

<Step S106>
While the transport motor 60 is rotating, the pulse count unit 81 detects the actual rotation amount of the transport screw 62 by counting the number of generated pulse signals.

<Step S107>
Further, while the transport motor 60 is rotating, the pulse interval timing unit 82 derives the detection pulse interval Tp.

<Step S108>
And the conveyance control part 84 determines whether the said actual rotation amount detected by process S106 reached | attained the said target rotation amount set by process S104 at any time.

<Step S109>
When it is determined that the actual rotation amount has reached the target rotation amount, the transport control unit 84 stops the transport motor 60. Thus, the toner conveyance control ends.

  In the following description, the target rotation amount when the detection pulse interval Tp represents a speed within the range of the reference rotation speed set in advance, that is, the target rotation set by the processing of steps S103 and S104. The amount is referred to as a first target rotation amount. Here, the detection pulse interval Tp is an example of the actual speed index value.

  Further, the target rotation amount when the detection pulse interval Tp represents a rotation speed that is slower than the reference rotation speed range is referred to as a second target rotation amount. Similarly, the target rotation amount when the detection pulse interval Tp represents a rotation speed faster than the reference rotation speed range is referred to as a third target rotation amount.

  In steps S102 to S104, the target rotation amount setting unit 83 sets the second target rotation amount to a larger amount than the first target rotation amount. That is, when the load applied to the conveyance motor 60 is small, that is, when the conveyance efficiency of the toner 9a by the conveyance screw 62 is low, the target rotation amount setting unit 83 sets the second target rotation amount larger than the first target rotation amount. Set the amount of rotation.

  On the other hand, in steps S102 to S104, the target rotation amount setting unit 83 sets the third target rotation amount to an amount smaller than the first target rotation amount. That is, when the load applied to the conveyance motor 60 is large, that is, when the conveyance efficiency of the toner 9a by the conveyance screw 62 is high, the target rotation amount setting unit 83 sets the third target rotation amount smaller than the first target rotation amount. Set the amount of rotation.

  If the toner supply device 5 is employed, the supply amount of the toner 9a to the developing device 43 can be stabilized even when the conveyance efficiency of the conveyance screw 62 varies depending on the condition of the toner 9a in the intermediate reservoir 61. Can do.

[Alarm processing]
Next, an example of an alarm processing procedure in the toner supply device 5 will be described with reference to a flowchart shown in FIG. The alarm processing is executed, for example, every time one image forming job is executed or every time one page of image forming processing is executed. In the following description, S201, S202,... Represent identification codes of steps executed by the control unit 8.

<Step S201>
First, the alarm control unit 85 determines whether or not the detection pulse interval Tp recorded in the data storage unit 87 is within a maximum fluctuation range from a preset lower limit interval Tpmin to an upper limit interval Tpmax.

  The maximum fluctuation range is the maximum fluctuation range of the detection pulse interval Tp when the toner 9a is a so-called genuine toner whose performance is guaranteed by the manufacturer of the image forming apparatus 10.

<Step S202>
When it is determined that the detection pulse interval Tp is within the maximum fluctuation range, the alarm control unit 85 has a track record that the conveying screw 62 has rotated in the reverse rotation direction opposite to the normal rotation direction in the previous alarm processing. It is determined whether or not.

  As will be described later, when the conveyance control unit 84 rotates the conveyance motor 60 in the reverse direction to rotate the conveyance screw 62 in the reverse rotation direction, the reverse rotation record information D1 is recorded in the data storage unit 87 (see FIG. 5 and step S206 of FIG. 7).

  Therefore, the alarm control unit 85 determines whether or not the reverse rotation record information D1 is recorded in the data storage unit 87, so that the record that the conveyance screw 62 has rotated in the reverse rotation direction in the previous alarm process is obtained. It is determined whether or not there is.

<Step S203>
In step S202, when the determination result that the conveyance screw 62 has not been rotated in the reverse rotation direction is obtained, the alarm control unit 85 has the detection pulse interval Tp larger than the preset first long interval To1. It is determined whether or not. The first long interval To1 is larger than the reference upper limit interval Tsmax and smaller than the upper limit interval Tpmax.

  The first long interval To1 corresponds to a first low rotation set speed that is slower than a preset range of the reference rotation speed. Therefore, the state in which the detection pulse interval Tp is larger than the first long interval To1 is a state in which the detection pulse interval Tp represents a rotation speed that is slower than the first low rotation set speed.

  The toner 9 a is condensed due to an excessive amount of the toner 9 a in the intermediate storage unit 61 or the humidity of the installation environment of the image forming apparatus 10 is high, and the toner 9 a is conveyed by the conveying screw 62. Efficiency may be higher than normal. The first long interval To1 is a threshold value for distinguishing whether or not the toner 9a in the intermediate reservoir 61 is in such a situation.

<Steps S204 and S205>
In step S203, when the determination result that the detection pulse interval Tp is larger than the preset first long interval To1 is obtained, the transfer control unit 84 transfers the transfer screw 62 in the direction of driving in the reverse rotation direction. The motor 60 is temporarily operated, and then the transport motor 60 is stopped.

  For example, in steps S <b> 204 and S <b> 205, the conveyance control unit 84 can reversely rotate the conveyance motor 60 for a predetermined time. As a result, the toner 9 a condensed in the intermediate storage unit 61 is loosened, and the toner 9 a in the intermediate storage unit 61 may be restored to a good state in which it is appropriately transported by the transport screw 62.

<Step S206>
Furthermore, the conveyance control unit 84 records reverse rotation record information D1 indicating the record of rotating the conveyance screw 62 in the reverse rotation direction in the data storage unit 87.

  When the processes of steps S204 to S206 are executed, the alarm control unit 85 ends the alarm process without executing the alarm output.

<Step S207>
In step S202, when the determination result that the conveyance screw 62 has a track record of rotating in the reverse rotation direction is obtained, the alarm control unit 85 has the detection pulse interval Tp larger than the preset second long interval To2. It is determined whether or not. Similarly to the first long interval To1, the second long interval To2 is larger than the reference upper limit interval Tsmax and smaller than the upper limit interval Tpmax.

  The second long interval To2 corresponds to a second low rotation set speed that is slower than a preset range of the reference rotation speed. Therefore, the state in which the detection pulse interval Tp is larger than the second long interval To2 is a state in which the detection pulse interval Tp represents a rotation speed that is slower than the second low rotation set speed.

  Similarly to the first long interval To1, the second long interval To2 is a situation in which the toner 9a of the toner 9a in the intermediate reservoir 61 is condensed and the transfer efficiency of the toner 9a by the transfer screw 62 is significantly deteriorated. It is a threshold value that divides

  It is conceivable that the second long interval To2 is the same as the first long interval To1. It is also conceivable that the second long interval To2 is slightly smaller than the first long interval To1.

<Step S208>
When the determination result that the detection pulse interval Tp is larger than the second long interval To2 is obtained in step S208, the alarm control unit 85 executes the first alarm output process. The alarm control unit 85 that executes the first alarm output process is an example of a first alarm output unit.

  The first alarm output process is a process of outputting a warning to the display unit 80 indicating that the toner supply device 5 is in a state where it cannot be recovered from an abnormal state and prompting the service center to be contacted. After the first alarm output process is performed, the alarm control unit 85 ends the alarm process.

<Step S209>
When the determination result that the detection pulse interval Tp is equal to or shorter than the first long interval To1 is obtained in step S203, and the determination result that the detection pulse interval Tp is equal to or smaller than the second long interval To2 is obtained in step S207. In the case, the process of step S209 is executed.

  In step S209, the alarm control unit 85 deletes the reverse rotation record information D1 in the data storage unit 87. Thereafter, the alarm control unit 85 ends the alarm process.

<Step S210>
In step S201, when the determination result that the detection pulse interval Tp is out of the maximum fluctuation range is obtained, the alarm control unit 85 executes the second alarm output process. The alarm control unit 85 that executes the second alarm output process is an example of a second alarm output unit.

  The second alarm output process is a process of outputting a warning to the display unit 80 indicating that the toner supply device 5 is in an abnormal state because the toner 9a is not the genuine toner. After the second alarm output process is performed, the alarm control unit 85 ends the alarm process.

[Toner supply control]
Next, an example of the procedure of toner replenishment control in the toner supply device 5 will be described with reference to the flowchart shown in FIG. The toner replenishment control is executed, for example, every time one image forming job is executed or every time an image forming process for one page is executed. In the following description, S301, S302,... Represent identification codes of steps executed by the control unit 8.

<Step S301>
First, the replenishment control unit 86 refers to the detection result of the toner level sensor 66 to determine whether or not the level of the toner 9a in the intermediate storage unit 61 is less than the allowable lower limit level.

<Step S302>
When the determination result that the level of the toner 9a in the intermediate storage unit 61 is less than the allowable lower limit level is obtained, the replenishment control unit 86 has the detection pulse interval Tp equal to or smaller than the preset third long interval To3. It is determined whether or not. The third long interval To3 is larger than the reference upper limit interval Tsmax.

  The third long interval To3 corresponds to a third low rotation set speed that is slower than a preset range of the reference rotation speed. Therefore, the state in which the detection pulse interval Tp is larger than the third long interval To3 is a state in which the detection pulse interval Tp represents a rotation speed that is slower than the third low rotation set speed.

  Similarly to the first long interval To1, the third long interval To3 is a condition in which the toner 9a of the toner 9a in the intermediate reservoir 61 is condensed and the conveyance efficiency of the toner 9a by the conveyance screw 62 is higher than usual. This is a threshold value for distinguishing between the two.

  It is conceivable that the third long interval To3 is the same as the first long interval To1. Further, it is conceivable that the third long interval To3 is slightly smaller than the first long interval To1.

  The situation where the efficiency of transporting the toner 9a by the transport screw 62 is higher than usual, that is, the situation where the toner 9a in the intermediate reservoir 61 is condensed is a situation where it is desirable not to add the toner 9a to the intermediate reservoir 61.

<Step S303>
In step S <b> 302, when the determination result that the detection pulse interval Tp is equal to or shorter than the third long interval To <b> 3 is obtained, the supply control unit 86 rotates the supply screw 52 by operating the supply motor 53. As a result, the toner 9 a is sent out from the toner container 51 to the intermediate reservoir 61.

<Step S304>
Furthermore, the replenishment control unit 86 continues the operation of the replenishment motor 53 until a predetermined end condition is satisfied.

  For example, it is conceivable that the end condition is that the state in which the level of the toner 9a in the intermediate reservoir 61 exceeds the allowable lower limit level continues for a predetermined time. It is also conceivable that the end condition is that a predetermined time elapses.

<Step S305>
When the termination condition is satisfied, the supply control unit 86 stops the supply screw 52 by stopping the supply motor 53. The supply control unit 86 ends the supply control after the process of step S305.

  If it is determined in step S302 that the detection pulse interval Tp is greater than the third long interval To3, the replenishment control unit 86 skips steps S303 to S305 and ends the replenishment control. .

  That is, the supply control unit 86 prohibits the operation of the supply screw 52 when the detection pulse interval Tp represents a rotation speed that is slower than the third low rotation set speed.

<Step S306>
In Step S301, when the determination result that the level of the toner 9a in the intermediate storage unit 61 is equal to or higher than the allowable lower limit level is obtained, the replenishment control unit 86 sets the detection pulse interval Tp to a short interval that is set in advance. It is determined whether it is less than Tu1. The short interval Tu1 is smaller than the reference lower limit interval Tsmin.

  The short interval Tu1 corresponds to a high rotation set speed that is faster than a preset range of the reference rotation speed. Therefore, the state in which the detection pulse interval Tp is smaller than the short interval Tu1 is a state in which the detection pulse interval Tp represents a rotation speed faster than the high rotation set speed.

  The short interval Tu1 is a threshold value that determines whether or not the amount of the toner 9a in the intermediate reservoir 61 is too small and the conveying screw 62 is idling. That is, the process of step S306 is a process for finding an abnormality in which the toner level sensor 66 erroneously detects the level of the toner 9a in the intermediate storage unit 61.

  When the determination result that the detection pulse interval Tp is less than the short interval Tu1 is obtained in step S306, the replenishment control unit 86 operates the replenishment screw 52 by executing the processes from step S303 to S305. Thereafter, the supply control unit 86 ends the supply control.

  On the other hand, when the determination result that the detection pulse interval Tp is equal to or longer than the short interval Tu1 is obtained in step S306, the supply control unit 86 ends the supply control without operating the supply motor 53.

  According to the replenishment control, the control of sending out the toner 9a to the intermediate reservoir 61 is appropriately executed according to the status of the toner 9a in the intermediate reservoir 61.

[Application example]
In the toner supply device 5, it is also conceivable that the pulse count unit 81 derives the actual speed index value instead of the pulse interval timing unit 82. In this case, the pulse count unit 81 counts the number of occurrences of the pulse signal per unit time, and derives the number of unit time pulses as a result of the count as the actual speed index value.

  The number of unit time pulses is proportional to the actual rotational speed of the conveying screw 62. Therefore, the state where the number of unit time pulses is small is a state where the actual rotation speed of the conveying screw 62 is low.

  The pulse counting unit 81 that counts the number of unit time pulses is an example of the actual speed index value deriving unit that derives the actual speed index value by detecting the actual rotation amount per unit time of the conveying screw 62. It is.

  When the number of unit time pulses is adopted as the actual speed index value instead of the detection pulse interval Tp, the number of unit time pulses in steps S203 and S207 in FIG. 7 and steps S302 and S306 in FIG. Is opposite to the magnitude relationship between the detection pulse interval Tp and the comparison target.

  It is also conceivable that the toner supply device 5 is a device that supplies the toner 9a to a so-called two-component developing type developing device. In this case, the magnetic roller 431 also functions as the developing roller 430 that supplies the toner 9 a to the photoreceptor 41.

  Further, the toner supply device 5 may be applied to the image forming apparatus 10 as a device that directly supplies the toner container 51 to the developing tank 43x of the developing device 43. In this case, the toner container 51 is an example of the storage unit.

  It should be noted that the toner supply device and the image forming apparatus according to the present invention can be freely combined within the scope of the invention described in each claim, or the embodiments and application examples shown above. It is also possible to configure by appropriately modifying or omitting a part.

2: Sheet feeding unit 3: Sheet conveying unit 4: Image forming unit 5: Toner supplying device 6: Toner conveying device 8: Control unit 9: Developer 9a: Toner 9b: Carrier 10: Image forming device 21: Sheet cassette 22: Pickup unit 30: Conveying path 40: Image forming unit 41: Photoconductor 42: Charging device 43: Developing device 43x: Developing tank 43y: Entrance of developing tank 44: Primary transfer device 45: Primary cleaning device 46: Optical scanning unit 47: Intermediate transfer belt 48: Secondary transfer device 49: Fixing device 50: Toner replenishing device 51: Toner container 51a: Toner container outlet 52: Replenishing screw 53: Replenishing motors 54, 63: Gear mechanism 60: Conveying motor 61: Intermediate storage Part (storage part)
61a: Intermediate storage portion inlet 61b: Intermediate storage portion outlet 61c: Bearing portion 61d: Transmission window 62: Conveying screw 62a: Shaft portion 62b: Blade portion 64: Pulse generation portion 65: Vertical duct 66: Toner level sensor 80: Display unit 81: Pulse count unit 82: Pulse interval time measuring unit (actual speed index value deriving unit)
83: target rotation amount setting unit 84: transport control unit 85: alarm control unit 86: replenishment control unit 87: data storage unit 101: discharge tray 430: developing roller 431: magnetic roller 432: magnet 433: stirring screw 434: blade 435 : Permeability sensor 470: Secondary cleaning device 641: Pulse rotator 641a: Detected part 641b: Opening 642: Photosensor D1: Reverse rotation record information Tp: Detection pulse interval

Claims (9)

A toner supply device for supplying toner to a developing device,
DC motor with brush,
The toner includes a shaft portion and a blade portion projecting spirally outward from the shaft portion, and is rotationally driven by the DC motor and rotates in a predetermined positive rotation direction in a storage portion that stores the toner. A conveying member that conveys to the outlet of the storage unit that leads to the developing device;
A target rotation amount setting unit for setting a target rotation amount of the conveying member;
A rotation amount detection unit for detecting an actual rotation amount of the conveying member;
A transport control unit that operates the DC motor until the actual rotation amount reaches the target rotation amount;
An actual speed index value corresponding to the actual rotation speed of the transport member is derived by detecting the time required for the rotation of the transport member by the unit rotation amount or the actual rotation amount per unit time of the transport member. A speed index value deriving unit,
The target rotation amount setting unit is a rotation speed at which the actual speed index value is faster than the reference rotation speed than the target rotation amount when the actual speed index value represents a preset reference rotation speed. A toner supply device that sets the target rotation amount to be large when   When the actual speed index value represents a rotational speed that is lower than a first low rotational speed setting that is lower than a preset reference rotational speed, the transport control unit moves the transport member in the normal rotational direction. The toner supply device according to claim 1, wherein the direct current motor is temporarily operated in a direction of driving in a reverse rotation direction opposite to the first rotation direction.   After the conveyance control unit operates the DC motor in a direction to drive the conveyance member in the reverse rotation direction, a second low rotation setting speed at which the actual speed index value is lower than the preset reference rotation speed The toner supply device according to claim 2, further comprising a first alarm output unit configured to output an alarm when the rotation speed is lower than that of the first alarm output unit. A delivery unit for delivering the toner from a toner container containing the toner to the storage unit;
A sending control unit for controlling the operation of the sending unit,
When the actual speed index value represents a rotational speed that is slower than a preset third rotational speed that is slower than the preset reference rotational speed, the sending control unit prohibits the operation of the sending unit; The toner supply device according to any one of claims 1 to 3.   5. The sending control unit operates the sending unit when the actual speed index value represents a rotational speed that is faster than a preset high rotational speed that is faster than the reference rotational speed. The toner supply device according to claim.   6. The toner supply device according to claim 1, further comprising: a second alarm output unit configured to output an alarm when the actual speed index value is out of a preset maximum fluctuation range. The rotation amount detector
A pulse generator that generates a pulse signal each time the conveying member rotates by a predetermined unit angle;
A pulse count unit that counts the number of occurrences of the pulse signal and derives a count result as the actual rotation amount;
The actual speed index value deriving unit measures the time required for generating the predetermined number of units of the pulse signal, or counts the number of generation of the pulse signal per unit time. The toner supply device according to claim 1, wherein an actual speed index value is derived.   The target rotation amount setting unit corrects a preset reference coefficient according to the actual speed index value, and further corrects the integrated value of the number of effective pixels in the image to be developed by the developing device and the corrected value. The toner supply device according to any one of claims 1 to 7, wherein a rotation amount calculated according to a coefficient is set as the target rotation amount. The toner supply device according to any one of claims 1 to 8,
An image forming apparatus comprising: a developing device to which toner is supplied from the toner supply device;

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