CN100465809C - Developing device, process cartridge provided with the same, and image forming apparatus - Google Patents

Abstract

The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile machine, etc., a process cartridge using the developing device, and an image forming apparatus. The volume of the first conveying screw 55Y is made larger than the volume of the second conveying screw 56Y, so that the developer level in the first developer housing 53Y for supplying the developer to the developing roller 51Y is higher than the developer level in the second developer housing 54Y for receiving the toner replenishment from above. In a developing device provided with two developer stirring and conveying screws and two developer accommodating portions, background contamination and toner scattering caused by a developer with insufficient charge amount generated can be prevented, and the phenomenon of 'uneven pitch of a conveying member' on an image can be prevented.

Description

Developing device, process cartridge and image forming device provided with the developing device

technical field

The present invention relates to a developing device used in image forming devices such as copiers, printers, and facsimile machines, a process cartridge using the developing device, and an image forming device.

Background technique

In the past, a two-component developing device with the following structure is known: two conveying screws are provided as developer agitating and conveying parts, and among the two conveying screws, the upper part of a certain conveying screw is arranged as a developer carrier. Built-in developing roller.

As such a developing device, for example, JP-A-2004-077554 (hereinafter abbreviated as "Patent Document 1") can be cited. The developing device will be described with reference to FIGS. 1-3 .

In the developing device 5 , a first conveying screw 55 and a second conveying screw 56 are provided, and the developing roller 51 is disposed obliquely above the first conveying screw 55 . The first transport screw 55 and the second transport screw 56 have approximately the same shape, have approximately the same volume and transport speed, and have approximately the same developer transport amount per unit time. In the developing device 5 , a partition wall 59 is provided between the first conveying screw 55 and the second conveying screw 56 to form the first developer storage portion 53 and the second developer storage portion 54 .

A toner supply port 61 is provided above the second transport screw 56 to supply toner as needed. Both ends of the partition wall 59 are openings, and the first conveying screw 55 and the second conveying screw 56 convey the developer in the opposite direction, and the developer circulates in the first developer storage part 53 and the second developer storage part 54 to carry out conveyance. . The volume inside the first developer accommodating portion 53 is substantially equal to the volume inside the second developer accommodating portion 54 . The conveying volumes of the first conveying screw 55 and the second conveying screw 56 are approximately equal, and the height of the developer in the first developer storage portion 53 is approximately equal to the height of the developer in the second developer storage portion 54 .

In the developing device 5 , the developer in the first developer storage portion 53 on the side of the first conveying screw 55 is sucked up by the developing roller 51 . In order to ensure a stable pumping amount, the height of the developer in the first developer storage portion 53 needs to reach a certain level. As shown in FIG.

However, the height of the developer in the first developer storage portion 53 and the height of the developer in the second developer storage portion 54 are substantially equal. Therefore, when the first developer storage portion 53 is in the state where the developer is accumulated on the top of the container, the inside of the second developer storage portion 54 is also in the state that the developer is accumulated on the top of the container. In this way, when the developer is accumulated on the upper part of the container in the second developer storage portion 54 , the second transport screw 56 is buried in the developer. If the second conveying screw 56 is buried in the developer, it is difficult for the blade portion of the second conveying screw 56 to agitate the upper part of the developer. In this state, when the toner is supplied from above the second developer accommodating portion 54 , the toner slides along the upper surface of the developer and is transferred to the first developer accommodating portion 53 without sufficient agitation. Inadequately stirred developer is insufficiently charged, and if it is used for development, background smearing or toner scattering may occur at the developing position.

As shown in FIG. 3 , by reducing the amount of developer in the developing device 5 , the amount of developer in the second developer storage portion 54 is reduced and placed at a lower position, thereby preventing background smearing caused by insufficiently charged developer. Dirty or toner scatter. However, if the amount of developer is reduced so that the amount of developer in the second developer storage portion 54 is reduced, the amount of developer in the first developer storage portion 53 is also reduced, and the pumping amount of the developer by the developing roller 51 becomes unstable. . Specifically, since the developer is at a lower position, the upper part of the vane of the first delivery screw 55 is higher than the developer, if the upper part of the vane is in a state above the developer, the position of the developer pushed by the vane will change. Higher, the position of the developer on the back side of the blade becomes lower. In this way, the amount of developer picked up by the developing roller 51 differs between the front and rear of the blade portion, and the amount of developer placed on the developing roller 51 becomes uneven. The uneven developer loading amount on the developing roller 51 causes an abnormal image called "uneven screw pitch".

The phenomenon of "uneven conveying pitch" is not limited to the case where the developer conveying member is a conveying screw, and the problem of "uneven conveying pitch" also exists if the developer conveying member conveys the developer by rotation.

Contents of the invention

The present invention is proposed to solve the above-mentioned problems in the prior art. The object of the present invention is to provide a developing device, a process cartridge and an image forming device using the developing device, which are equipped with two developer agitating and conveying devices. In a developing device with two parts and two developer storage parts, it is possible to prevent background smearing and toner scattering caused by the generation of insufficiently charged developer, and to prevent the occurrence of "uneven pitch of the conveying member" on the image.

In order to achieve the above object, the present invention proposes the following schemes:

(1) A developing device, comprising:

The developer carrier is used to carry the developer;

The developer storage part accommodates the developer and is provided with an opening;

the first developer agitating and conveying member rotates, agitates and conveys the developer in the developer storage portion, and supplies the developer to the developer carrier;

The second developer agitating and conveying member, by rotating, agitates the developer in the developer storage portion, and conveys the developer in a direction opposite to the developer conveying direction of the first developer agitating and conveying member;

Partition walls located between the first developer agitating and conveying member and the second developer agitating and conveying member, at both ends along the rotation axis direction of the first developer agitating and conveying member or the second developer agitating and conveying member, become an opening through which the developer can pass;

Among the spaces separated by the partition wall, the height of the developer in the space where the first developer agitating and conveying member is installed is higher than that in the space where the second developer agitating and conveying member is installed.

(2) In the developing device of (1), the volume of the first developer agitating and conveying member is made larger than the volume of the second developer agitating and conveying member.

(3) In the developing device of (2), the first developer agitating and conveying member and the second developer agitating and conveying member are composed of a shaft portion and a blade portion, and the shaft of the first developer agitating and conveying member The shaft diameter of the second developer stirring and conveying member is larger than the shaft diameter of the second developer agitating and conveying member.

(4) In the developing device of (2), the first developer agitating and conveying member and the second developer agitating and conveying member are composed of a shaft portion and a blade portion, and the blades of the first developer agitating and conveying member The portion is thicker than the blade portion of the second developer stirring and conveying member.

(5) In the developing device of (2), the first developer agitating and conveying member and the second developer agitating and conveying member are composed of a shaft portion and a blade portion, and the blades of the first developer agitating and conveying member A plurality of blades are provided on the upper part, and the blades have the same pitch, and the number of blades of the first developer agitating and conveying member is more than that of the second developer agitating and conveying member.

(6) In the developing device of (1), the first developer agitating and conveying member and the second developer agitating and conveying member are composed of a shaft portion and a blade portion, and the development of the first developer agitating and conveying member The agent conveying speed is slower than the developer conveying speed of the second developer agitating and conveying member.

(7) In the developing device of (6), the pitch of the blade portion of the first developer agitating and conveying member is smaller than the pitch of the blade portion of the second developer agitating and conveying member.

(8) In the developing device according to (6), the blade portion of the first developer agitating and conveying member is notched.

(9) In the developing device of (6), a plate-shaped member parallel to the shaft portion of the first developer agitating and conveying member is provided on the first developer agitating and conveying member.

(10) A process cartridge comprising at least:

like a carrier;

developing means for developing the latent image on the image carrier;

The image carrier and the developing means are supported as a whole, and can be freely loaded and disassembled relative to the image forming device body; it is characterized in that:

The developing device of any one of the above (1)-(9) is used as the developing means.

(11) An image forming device comprising:

Charging means, making the surface of the image carrier charged;

latent image forming means for forming an electrostatic latent image on the image carrier;

Developing means, develop described electrostatic latent image, make it become toner image; It is characterized in that:

As the developing means, the developing device of any one of the above (1) to (9) or the process cartridge of the above (10) is used.

In the developing device of the present invention, in the process cartridge and the image forming apparatus using the developing device, the height of the developer in the first developer storage part that supplies the developer to the developer carrier is higher than that of the developer in the second developer storage part. Dose height is high. In this way, even if the developer in the first developer accommodating portion is filled up to the upper part of the accommodating portion in order to stabilize the amount of developer absorbed by the developer carrier, the developer in the second developer accommodating portion will not be filled. to the upper part of the storage section. By making the developer in the first developer accommodating portion fill up to the upper portion of the accommodating portion, it is possible to prevent the occurrence of “uneven conveying pitch” on the image. In addition, the developer in the second developer storage section will not fill the upper part of the storage section, so the upper part of the second conveying screw is exposed from the developer surface, and the developer in the second developer storage section can be sufficiently obtained. Stir to prevent undercharged developer from occurring.

According to the developing device of the present invention, the process cartridge and image forming apparatus using the developing device can prevent background smearing or toner scattering caused by insufficiently charged developer, and prevent "conveyance pitch unevenness" from occurring on the image. "Phenomenon.

Description of drawings

FIG. 1 is a diagram for explaining a first problem of a conventional developing device;

Fig. 2 is a perspective view of two conveying screws of a conventional developing device;

3 is a diagram for explaining a second problem of a conventional developing device;

4 is a schematic configuration diagram of a printer according to Embodiment 1 of the present invention;

Fig. 5 shows an enlarged structural view of the process cartridge for Y of the printer and its surroundings;

6 is a perspective view of a replenishing device for replenishing toner from a toner bottle of the printer to a developing device;

Fig. 7 shows a vertical cross-sectional view of the Y-use developing device of the printer along the photoreceptor axis;

Fig. 8 shows a perspective view of the Y-use developing device of the printer with the upper cover removed;

Figure 9 shows a perspective view of the developing roller and the frame member removed from the developing device shown in Figure 8;

10 is a cross-sectional view illustrating the state of the developer of the developing device for Y of the printer;

Fig. 11 is a perspective view of two conveying augers involved in Embodiment 1 of the present invention;

Fig. 12 is a perspective view of two conveying augers involved in Embodiment 2 of the present invention;

Fig. 13 is a perspective view of two conveying augers involved in Embodiment 3 of the present invention;

14 is a cross-sectional view illustrating the state of the developer of the developing device for Y according to Modification 1 of the present invention;

Fig. 15 is a perspective view of two conveying augers involved in Embodiment 4 of the present invention;

Fig. 16 is a perspective view of two conveying augers involved in Embodiment 5 of the present invention;

Fig. 17 is a perspective view of two conveying augers involved in Embodiment 6 of the present invention;

18 is a plan view of a developing device according to Modification 2 of the present invention;

Detailed ways

Next, preferred embodiments and examples of the present invention will be described with reference to the drawings.

In the following embodiments, although various limitations are made on constituent elements, types, combinations, shapes, relative arrangements, etc., these are merely examples, and the present invention is not limited thereto.

Embodiment 1

Next, an electrophotographic printer (hereinafter abbreviated as "printer") 100 will be described as an example of an embodiment of an image forming apparatus to which the present invention is applied. Regarding the image forming unit, a process cartridge will be described.

First explain the basic structure of the printer 100. FIG. 4 is a schematic structural diagram of the printer 100. In FIG. , black toner like. In the present invention, the added symbol Y represents yellow, C represents cyan, M represents magenta, and K represents black. The four process cartridges 6Y, 6M, 6C, and 6K differ only in the color of the image forming material, and are identical in other configurations, and are replaced when their lifespan is reached.

Taking the process cartridge 6Y for generating Y toner images as an example, as shown in FIG. ), the charging device 4Y, the developing device 5Y, and the like. The process cartridge can be attached to and detached from the main body of the printer 100, and consumable parts can be replaced.

The photoreceptor 1Y is driven to rotate clockwise in the figure by a driving means (not shown), and the charging device 4Y makes the surface of the photoreceptor 1Y uniformly charged. The uniformly charged photoreceptor 1Y surface is exposed and scanned by laser light L to form an electrostatic latent image for Y. The Y electrostatic latent image is then developed by the developing device 5Y using the Y toner. Next, it is transferred onto the intermediate transfer belt 8 . After the intermediate transfer process, the toner remaining on the surface of the photoreceptor 1Y is removed by the cleaning device 2Y. The neutralizer eliminates the residual charge of the cleaned photoreceptor 1Y. After the electricity is removed, the surface of the photoreceptor 1Y is initialized and is ready for image formation thereafter. Similarly, the other process cartridges 6M, 6C, and 6K form M, C, and K toner images on the photoreceptors 1M, 1C, and 1K, respectively, and transfer them to the intermediate transfer belt 8 .

Below the process cartridges 6Y, 6M, 6C, and 6K, an exposure device 7 is arranged. The exposure device 7 as means for forming a latent image irradiates laser light based on image information on each of the photoreceptors of the process cartridges 6Y, 6M, 6C, and 6K to perform exposure. By this exposure, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. In the exposure device 7, the motor drives the polygon mirror to rotate, and the laser light L emitted from the light source is irradiated onto the photoreceptor through several optical lenses and mirrors while scanning.

On the lower side and the right side of the exposure device 7, paper feeding means including a paper storage cassette 26, a paper feeding roller 27, and a pair of registration rollers 28 are arranged. The paper storage cassette 26 stores a plurality of stacked transfer paper P as a recording medium, and the paper feed roller 27 is in contact with the uppermost transfer paper P. The paper supply roller 27 is driven to rotate counterclockwise by a driving means (not shown), and the uppermost transfer paper P is fed between the rollers of a pair of registration rollers 28, and the registration rollers 28 hold the transfer paper P. , temporarily stop turning. Then, the transfer paper P is sent toward the secondary transfer nip at an appropriate timing. In the paper feeding means, the conveying means is constituted by a combination of a paper feeding roller 27 and a pair of registration rollers 28 . This transport means transports the transfer paper P from the paper storage cassette 26 to the secondary transfer nip.

Above the process cartridges 6Y, 6M, 6C, 6K, an intermediate transfer assembly 15 including an intermediate transfer belt 8 as an intermediate transfer body, which is an endless belt, is disposed. In addition to the intermediate transfer belt 8, the intermediate transfer unit 15 is provided with four primary transfer bias rollers 9Y, 9M, 9C, 9K, a cleaning device 10, a secondary transfer backing roller 12, a cleaning backing roller Roller 13, Tension Roller 14, etc. The intermediate transfer belt 8 is supported by the secondary transfer backing roller 12, the cleaning backing roller 13, and the tension roller 14. Among the three rollers, at least one roller is a driving roller, which is driven to rotate so that The intermediate transfer belt 8 moves counterclockwise in the figure.

The primary transfer bias rollers 9Y, 9M, 9C, and 9K cooperate with the photoreceptors 1Y, 1M, 1C, and 1K respectively to clamp the intermediate transfer belt 8 to form a primary transfer nip. In this embodiment, a transfer bias of a polarity opposite to that of the toner, eg, positive, is applied to the back surface of the intermediate transfer belt 8 (inner peripheral surface of the endless belt). Rollers other than the primary transfer bias rollers 9Y, 9M, 9C, and 9K are all grounded. When the intermediate transfer belt 8 sequentially passes through the primary transfer nip, the Y, M, C, and K toner images on the photoreceptors 1Y, 1M, 1C, and 1K are superimposed and transferred on the intermediate transfer belt 8 Above, this is called "primary transfer", and a four-color superposed toner image (hereinafter abbreviated as "four-color toner image") is formed on the intermediate transfer belt 8 .

The intermediate transfer belt 8 is sandwiched between the secondary transfer backup roller 12 and the secondary transfer roller 19 to form a secondary transfer nip. The four-color toner images formed on the intermediate transfer belt 8 are transferred onto the transfer paper P at the secondary transfer nip. Transfer residual toner that has not been transferred onto the transfer paper P adheres to the intermediate transfer belt 8 after passing through the secondary transfer nip. This transfer residual toner is cleaned by the cleaning device 10 .

At the secondary transfer nip, the transfer paper P is nipped between the surface-moving intermediate transfer belt 8 and the secondary transfer roller 19 , and the transfer paper P is carried toward the fixing device 20 . The transfer paper P sent out from the secondary transfer nip passes between rollers of the fixing device 20 and is subjected to heat and pressure, whereby the four-color toner images are fixed. Thereafter, the transfer paper P passes through a pair of discharge rollers 29 and is discharged out of the machine. A stacking part 30 is formed on the printer body, and the transfer paper P discharged out of the machine through the paper discharge roller 29 is sequentially stacked on the stacking part 30 .

In FIG. 1 , a bottle storage 31 is disposed between the intermediate transfer unit 15 and the stacking unit 30 . The bottle storage 31 accommodates toner bottles 32Y, 32M, 32C, and 32K as toner storage containers for storing toners Y, M, C, and K, respectively. The toner bottles 32Y, 32M, 32C, and 32K are arranged in order from top to bottom in the bottle storage 31 . The toners Y, M, C, and K in the toner bottles 32Y, 32M, 32C, and 32K are supplied to the developing devices in the process cartridges 6Y, 6M, 6C, and 6K by the toner replenishing means. The toner bottles 32Y, 32M, 32C, and 32K and the process cartridges 6Y, 6M, 6C, and 6K are independent, and can be attached to and detached from the printer 100 body.

FIG. 6 shows a perspective view of a toner supply device 40Y that supplies toner from a toner bottle 32Y of the printer to the developing device 5Y. In the main body of the printer 100 , a toner replenishing device 40Y for supplying the yellow toner in the toner bottle 32Y to the developing device 5Y is provided below the installation position of the toner bottle 32Y. In FIG. 6, only a portion of the developing device 5Y of the process cartridge 6Y is shown. The process cartridge 6Y slides in the direction of the arrow α in the figure, and is set in the main body of the printer 100 . The conveying pipe 43Y conveys the toner to the developing device 5Y, and the tip of the conveying pipe 43Y is connected to the toner replenishing portion 58Y of the developing device 5Y.

New toner filled in the toner bottle 32Y is supplied to the toner hopper portion 48Y of the toner supply device 40Y. Toner detecting means (not shown) is provided in the developing device 5Y, and when it is judged by the toner detecting means that the toner density in the developing device 5Y is low, the toner stored in the toner hopper part 48Y Replenish to the developing device 5Y. The toner replenished to the developing device 5Y is passed from the toner hopper portion 48Y through the conveying pipe 43Y, and is supplied from the opening 45Y of the conveying pipe 43Y to the toner supply port 61Y on the developing device side.

Next, the configuration of the developing device 5Y inside the process cartridge 6Y will be described. 7 shows an enlarged sectional view of the developing device 5Y viewed from the photoreceptor axial direction, FIG. 8 shows a perspective view of the developing device 5Y of the printer with the upper cover 70Y removed, and FIG. 9 shows the developing roller 51Y removed from the state shown in FIG. 8 and a perspective view of the frame member 71Y.

In the developing device 5Y, a developing roller 51Y serving as a developer carrier is partially exposed from an opening of the casing thereof. The developing roller 51Y is composed of a magnetic roller as a magnetic field generating means, and a developing sleeve. The magnetic roller is provided with five magnets P1, P2, P3, P4, and P5. The developing sleeve rotates coaxially around the magnets. Among the magnets P1, P2, P3, P4 and P5, the magnets P3 and P4 are set to generate magnetic fields of the same polarity, and other adjacent magnets are set to generate magnetic fields of different polarities. At a position facing the downstream side of the magnet P5 along the moving direction of the surface of the developing sleeve, a developing blade 52Y is provided as a developer regulating member for regulating the layer thickness of the developer.

Below the developing roller 51Y, a developer storage portion for storing developer is provided, and is divided into a first developer storage portion 53Y and a second developer storage portion 54Y located on the developing roller 51Y side by a partition wall 59Y. In the first developer accommodating portion 53Y, a first conveying screw 55Y as a first developer agitating and conveying member is provided, and in the second developer accommodating portion 54Y, a second developer agitating and conveying member is provided. Shipping screw 56Y. The first conveying screw 55Y and the second conveying screw 56Y have a spiral shape composed of a shaft portion and a blade portion.

Between the developing roller 51Y and the first conveyance screw 55Y, there is provided a frame member 71Y on which a communicating port 72Y is provided for passing the developer. The partition wall 59Y that separates the developer storage section forms a first opening 59Ya and a second opening 59Yb at both ends of the developer storage section, and the developer can pass through the first opening 59Ya and the second opening 59Yb.

In the developing device 5Y of Embodiment 1, a two-component developer consisting of toner and a carrier is used, but the present invention is not limited thereto, and a one-component developer not including a carrier may be used.

In the developing device 5Y, the toner and the carrier are stored inside in advance as a developer, and the toner is consumed due to development. As shown in FIG. Replenish toner.

Next, the operation of the developing device 5Y will be described.

The toner supplied from the toner bottle 32Y to the developing device 5Y is supplied into the developing device 5Y from a toner supply port 61Y (shown by a dotted line in FIGS. 8 and 9 ). The toner supplied to the second developer accommodating portion 54Y of the developing device 5Y is stirred together with the carrier by the second conveying screw 56Y. The developer composed of toner and carrier in the second developer storage portion 54Y is conveyed in the arrow B direction in the drawing while being agitated by the second conveyance screw 56Y. The developer that has reached the end of the second developer accommodating portion 54Y is conveyed by the second conveying screw 56Y and moves to the first developer accommodating portion 53Y through the first opening portion 59Ya. The developer in the first developer storage portion 53Y is conveyed in the direction of the arrow A in the drawing while being stirred by the first conveyance screw 55Y, reaches the end of the first developer storage portion 53Y, passes through the second opening 59Yb, and moves to the end of the first developer storage portion 53Y. to the second developer storage portion 54Y. In this way, the developer circulates in the developing device 5Y through the first conveying screw 55Y and the second conveying screw 56Y.

Among the developers stirred and conveyed by the first conveying screw 55Y in the first developer storage portion 53Y, the developer close to the developing roller 51Y is placed on the developing roller 51Y. The carrier in the developer is attracted by the magnetic force generated by the magnet P4 or P5 in the magnetic roller, and is placed on the developing roller 51Y. The toner in the developer is stirred, charged with a polarity opposite to that of the carrier, an electrostatic force acts between the toner and the carrier, and is placed on the developing roller 51Y together with the carrier. The developer loaded on the developing roller 51Y passes through the gap (blade gap) between the developing blade 52Y and the surface of the developing roller 51Y, and the layer thickness is restricted. The developer whose layer thickness is limited is transported to the developing region facing the photoreceptor 1, and is brought into a spiked state on the developing roller 51Y due to the influence of the magnetic force generated by the magnet P1 in the magnetic roller.

In this embodiment, the surface of the developing roller 51Y moves in the same direction at a faster linear velocity than the surface of the photoreceptor 1Y in the developing region. The carrier standing on the developing roller 51Y supplies the toner adhering to the surface of the carrier to the surface of the photoreceptor 1Y while sliding the surface of the photoreceptor 1Y. At this time, a developing bias is applied to the developing roller 51Y by a power source (not shown), so that a developing electric field is formed in the developing region. Between the electrostatic latent image on the photoreceptor 1Y and the developing roller 51Y, an electrostatic force that moves the toner on the developing roller 51Y toward the electrostatic latent image side acts. Therefore, the toner on the developing roller 51Y adheres to the electrostatic latent image on the photoreceptor 1Y. By the toner being attached to the electrostatic latent image on the photoreceptor 1Y, the electrostatic latent image on the photoreceptor 1Y is developed into a toner image of a corresponding color.

In this embodiment, the developing roller 51Y is connected to the driving device through a clutch, and the rotation of the developing roller 51Y can be temporarily stopped by the clutch.

In the conventional developing device 5 described with reference to FIG. 1 , FIG. 2 , and FIG. 3 , it is difficult to prevent generation of insufficiently charged developer, and it is difficult to prevent occurrence of "uneven pitch".

The developing device 5 includes a casing forming a developer storage section and a casing serving as a cover from above. in a low position. In such a developing device 5, in order to prevent the phenomenon of "uneven pitch", if the developer becomes full in the first developer storage part 53 and the second developer storage part 54, it will flow from the two casings. The developer leaks from the gap at the boundary on the side of the second developer storage portion 54 , causing the developer to scatter.

Furthermore, in order to make both the first developer accommodating portion 53 and the second developer accommodating portion 54 full of developer, it is necessary to fill the developing device with developer containing a large amount of carrier in advance. In addition, when the second developer accommodating portion 54 is filled with developer, the torque acting on the second conveying screw 56Y is large, and the motor and gears that rotate the second conveying screw 56Y must bear the large torque.

Therefore, in this embodiment, in order to prevent the generation of insufficiently charged developer and prevent the phenomenon of "uneven conveying pitch", the volume of the first conveying screw 55Y is larger than that of the second conveying screw 56Y.

Thus, the volume of the first conveying screw 55Y is large compared with the volume of the second conveying screw 56Y, and FIG. 10 shows a sectional view of a developing device 5Y using such two conveying screws viewed from the axial direction. Since the volume of the first conveying screw 55Y is larger than that of the second conveying screw 56Y, the space for storing the developer in the first developer storage portion 53Y is narrower than the space for storing the developer in the second developer storage portion 54Y. If the space for storing the developer is narrow, as shown in FIG. 10 , the height of the developer in the first developer storage portion 53Y is higher than that in the second developer storage portion 54Y.

In this way, even if the developer in the first developer storage portion 53Y is filled up to the upper part of the storage portion in order to stabilize the amount of developer that is sucked up by the developing roller 51Y, there will be no development in the second developer storage portion 54Y. The agent is in the state of being filled up to the upper part of the storage part.

The developer in the first developer storage portion 53Y is filled up to the upper portion of the storage portion, and the amount of developer absorbed by the developing roller 51Y is stabilized, which prevents the phenomenon of “uneven conveying pitch” on the image.

Since the developer in the second developer accommodating portion 54Y is not filled up to the upper portion of the accommodating portion, the upper portion of the second conveying screw 56Y is exposed from the surface of the developer, and in the second developer accommodating portion 54Y, The developer is sufficiently stirred, and the occurrence of an insufficiently charged developer can be prevented. In this way, it is possible to prevent image background smearing caused by the use of insufficiently charged developer for development, and prevent toner scattering at the development position.

In addition, it is possible to prevent the developer from leaking and scattering from the casing gap due to the developer clogging in the second developer storage portion 54Y.

Furthermore, compared with the conventional one, the amount of developer in the developing device 5Y can be reduced, and an increase in the rotational torque of the second conveyance screw 56Y can be suppressed. Since the developer amount in the developing device 5Y is reduced, cost can be reduced.

When the developing device 5Y is installed at the beginning of the main body of the printer 100, the height of the developer in the first developer storage portion 53Y and the developer in the second developer storage portion 54Y are substantially the same. Since the volume in which the first developer storage portion 53Y can store the developer is small, the developer amount is small.

Next, if the heights are the same, the amount of developer passing through the first opening 59Ya is larger than the amount of developer passing through the second opening 59Yb, and the amount of developer in the first developer storage portion 53Y increases. When the amount of developer in the first developer storage portion 53Y increases, the height of the developer in the first developer storage portion 53Y becomes higher, and the amount of developer passing through the second opening 59Yb also increases. In a state where the amount of developer passing through the first opening 59Ya per unit time is substantially equal to the amount of developer passing through the second opening 59Yb, the amount of developer in both developer storage portions is stabilized. In this way, when the developer amount is stabilized, the state shown in FIG. 10 will be obtained.

If there is a large difference in the amount of developer conveyed by the first conveying screw 55Y and the second conveying screw 56Y, the developer will remain at the starting point of conveyance by the first conveying screw 55Y, that is, in the vicinity of the first opening 59Ya, and the developer will remain at the end of the developing device for a while. As the developer amount increases, the developer height position becomes higher. If the height position of the developer becomes higher at the end of the developing device, the developer will enter the gap between the end of the developing roller 51Y and the casing member of the developing device 5Y, and the developing roller 51Y will be braked, or the developer will flow toward the developing roller 51Y. External leaks. However, the developing device 5Y is provided with a frame member 71Y which has a communicating port 72Y and which fills up the upper portion of the first opening 59Ya. In this way, even if the amount of developer increases temporarily at the end of the developing device and the height of the developer increases, it is possible to prevent the developer from reaching the end of the developing roller 51Y.

Example 1

Embodiment 1 of a specific structure in which the volume of the first conveying screw 55Y is larger than that of the second conveying screw 56Y will be described below.

FIG. 11 is a perspective view of the first conveying screw 55Ya and the second conveying screw 56Y used in the developing device 5Y according to Embodiment 1 of the present invention. As shown in FIG. 11, the shaft diameter of the first conveying screw 55Ya for the developing device 5Y is larger than that of the second conveying screw 56Y, and therefore, the volume of the first conveying screw 55Ya is larger than that of the second conveying screw 56Y. Specifically, a screw member with a shaft diameter of 7.0 mm was used as the first conveying screw 55Ya, and a screw member with a shaft diameter of 5.0 mm was used as the second conveying screw 56Y. In addition to the different shaft diameters, other things such as the pitch width of the blades, the rotation speed of the screw, etc., are the same.

The inventors set the shaft diameters of the first conveying screw 55Ya to four types: 5.0mm, 6.0mm, 7.0mm, and 8.0mm, and conducted a comparative study. Compared with the conventional shaft diameter of 5.0 mm, when the shaft diameter of the first conveying screw 55Ya is set to 6.0 mm or 7.0 mm, the occurrence of "uneven pitch" is improved. However, when the shaft diameter of the first conveying screw 55Y is set to 8.0 mm, the amount of developer in the first developer storage portion 53Y is too large, and the rotation of the screw is braked. Further comparing the situation when the shaft diameter of the first conveying screw 55Y is 6.0mm and 7.0mm, it is found that the shaft diameter of 7.0mm is better, therefore, the shaft diameter of the first conveying screw 55Ya is set to 7.0mm.

As described above, by making the shaft diameter of the first conveyance screw 55Ya for the developing device 5Y larger than that of the second conveyance screw 56Y, the volume of the first conveyance screw 55Ya is larger than that of the second conveyance screw 56Y. As shown in FIG. 10 , the developer level in the first developer storage portion 53Y is higher than the developer level in the second developer storage portion 54Y. In this way, it is possible to prevent the generation of insufficiently charged developer, and to prevent the phenomenon of "uneven conveying pitch" from occurring on the image.

Example 2

Next, a second embodiment of a specific structure in which the volume of the first conveying screw 55Y is larger than that of the second conveying screw 56Y will be described.

FIG. 12 is a perspective view of the first conveying screw 55Yb and the second conveying screw 56Y used in the developing device 5Y according to Embodiment 2 of the present invention. As shown in FIG. 12, the blades of the first conveyance screw 55Yb for the developing device 5Y are thicker than the second conveyance screw 56Y, and therefore, the volume of the first conveyance screw 55Yb is larger than that of the second conveyance screw 56Y. Except for the difference in blade thickness, other factors such as shaft diameter and pitch width of the blade are the same.

By making the blade thickness of the first conveyance screw 55Yb for the developing device 5Y thicker than that of the second conveyance screw 56Y, the volume of the first conveyance screw 55Yb is larger than that of the second conveyance screw 56Y. As shown in FIG. 10 , the developer level in the first developer storage portion 53Y is higher than the developer level in the second developer storage portion 54Y. In this way, it is possible to prevent the generation of insufficiently charged developer, and to prevent the occurrence of "uneven conveying pitch" on the image.

Example 3

Next, a third embodiment of a specific structure in which the volume of the first conveying screw 55Y is larger than that of the second conveying screw 56Y will be described.

FIG. 13 is a perspective view of a first conveying screw 55Yc and a second conveying screw 56Y used in a developing device 5Y according to Embodiment 3 of the present invention. As shown in FIG. 13, the number of blades of the first conveying screw 55Yc for the developing device 5Y is larger than that of the second conveying screw 56Y, and therefore, the volume of the first conveying screw 55Yc is larger than that of the second conveying screw 56Y. Specifically, the second transport screw 56Y has a shape in which one blade is wound around the shaft, and the first transport screw 55Yc has a shape in which two blades are wound around the shaft. In addition to the different number of blades, other factors such as shaft diameter, blade pitch width, blade thickness, etc., are the same.

By making the number of blades of the first conveyance screw 55Yc for the developing device 5Y larger than that of the second conveyance screw 56Y, the volume of the first conveyance screw 55Yc is larger than that of the second conveyance screw 56Y. As shown in FIG. 10 , the developer level in the first developer storage portion 53Y is higher than the developer level in the second developer storage portion 54Y. In this way, it is possible to prevent the generation of insufficiently charged developer, and to prevent the occurrence of "uneven conveying pitch" on the image.

In Embodiments 1 to 3 above, the yellow developing device 5Y was used. The developing devices 5M, 5C, and 5K using other colors are the same as the developing device 5Y except for the toner color. Therefore, the conveying screws described in the above-mentioned Embodiments 1-3 can also be applied to the developing devices 5M, 5C, 5K.

As described above, according to the developing device 5Y of Embodiment 1, by making the volume of the first conveying screw 55Y larger than that of the second conveying screw 56Y, the developer in the first developer accommodating portion 53Y is supplied to the developing roller 51Y. The height is higher than the height of the developer inside the second developer storage portion 54Y that receives toner replenishment from above. In this way, even if the developer in the first developer accommodating portion 53Y is filled up to the upper part of the accommodating portion in order to stabilize the amount of developer that is sucked up by the developing roller 51Y, the developer in the second developer accommodating portion 54Y will not Stuffed to the upper part of the storage part. By making the developer in the first developer storage portion 53Y fill up to the upper portion of the storage portion, it is possible to prevent the “conveyance pitch unevenness” from occurring on the image. Furthermore, the developer in the second developer storage portion 54Y does not fill up the upper portion of the storage portion, so the upper portion of the second conveyance screw 56Y is exposed from the developer surface, and the developer in the second developer storage portion 54Y Stirring can be sufficiently obtained, and the generation of a developer with insufficient charge amount can be prevented. In this way, by using the developing device 5Y, it is possible to prevent background smearing and toner scattering caused by insufficiently charged developer, and to prevent the phenomenon of "uneven conveyance pitch" from occurring on the image.

It can prevent the developer from scattering from the gap due to the developer clogging, prevent the occurrence of abnormal images, and prevent the inside of the machine from being soiled. Since it can prevent the inside of the machine from getting dirty, the hands of the operator will not be soiled when replacing consumables, preventing the operator from feeling uncomfortable when replacing consumables.

Compared with the prior art, the amount of developer in the developing device 5Y can be reduced, the rotation torque of the second conveying screw 56Y can be reduced, and the wear of the driving part can be reduced. In this way, the failure of the device is less, and the life of the device is prolonged.

By making the shaft diameter of the first conveying screw 55Ya for the developing device 5Y larger than that of the second conveying screw 56Y, the volume of the first conveying screw 55Y is larger than that of the second conveying screw 56Y.

By making the blades of the first conveyance screw 55Yb for the developing device 5Y thicker than the second conveyance screw 56Y, the volume of the first conveyance screw 55Y is larger than that of the second conveyance screw 56Y.

By making the number of blades of the first conveyance screw 55Yc for the developing device 5Y larger than that of the second conveyance screw 56Y, the volume of the first conveyance screw 55Y is larger than that of the second conveyance screw 56Y.

By making the volume of the first conveying screw 55Y larger than that of the second conveying screw 56Y, the strength of the first conveying screw 55Y is increased. In addition, in each of the above-mentioned embodiments, the cross-sectional area of the first conveying screw 55Y is made larger than conventional ones, the vibration caused by rotation is small, and the swinging accuracy can be improved.

The developing device 5Y together with at least the photoreceptor 1Y constitutes a process cartridge 6Y, which can be attached and detached from the main body of the printer 100, enabling one-time replacement of consumable parts. In this manner, it is possible to provide a process cartridge capable of preventing background smearing and toner scattering caused by insufficiently charged developer, and preventing "conveyance pitch unevenness" from occurring on an image.

The printer 100 is provided with the developing devices 5Y, 5M, 5C, and 5K. In this way, an image forming apparatus can be provided that can prevent background smearing or toner scattering caused by insufficiently charged developers, and prevent "carrying" on the image. Uneven pitch" phenomenon.

Modification 1

In Embodiment 1, by making the volume of the first conveying screw 55Y larger than that of the second conveying screw 56Y, the space for storing the developer in the first developer storage part 53Y is larger than the space for storing the developer in the second developer storage part 54Y. The space for the agent is small. Since the space for storing the developer is narrow, the height of the developer becomes higher. As shown in FIG. 10 , the height of the developer in the first developer storage portion 53Y is higher than that in the second developer storage portion 54Y. As a structure that makes the space for storing the developer in the first developer storage portion 53Y narrower than the space for storing the developer in the second developer storage portion 54Y, it is not limited to the above-mentioned structures.

Next, the structure of Modification 1 will be described, in which the volume of the first developer accommodating portion 53Y is smaller than that of the second developer accommodating portion 54Y, so that the space for accommodating the developer in the first developer accommodating portion 53Y is smaller than that of the second developer accommodating portion 53Y. The space for storing the developer in the developer storage portion 54Y is narrow.

FIG. 14 is a cross-sectional view of the transport screw of the developing device 5Y viewed from the axial direction according to Modification 1 of the present invention. As shown in FIG. 14 , the volume of the first developer accommodating portion 53Y is made smaller than the volume of the second developer accommodating portion 54Y. By making the volume of the first developer accommodating portion 53Ya smaller than that of the second developer accommodating portion 54Y, the developer inside the first developer accommodating portion 53Ya is kept in a plugged state even in order to stabilize the amount of developer that is sucked up by the developing roller 51Y. Even if the container is full to the upper part of the storage part, the developer in the second developer storage part 54Y will not be full to the upper part of the storage part.

The developer in the first developer storage portion 53Ya is filled up to the top of the storage portion, and the amount of developer absorbed by the developing roller 51Y is stabilized, thereby preventing “uneven transport pitch” from occurring on the image.

Since the developer in the second developer accommodating portion 54Y is not filled up to the upper portion of the accommodating portion, the upper portion of the second conveying screw 56Y is exposed from the surface of the developer, and in the second developer accommodating portion 54Y, The developer is sufficiently stirred, and the occurrence of an insufficiently charged developer can be prevented.

In this manner, in the developing device 5Y of Modification 1, as in the first embodiment, it is possible to prevent image background smearing caused by the use of developer with an insufficiently charged amount for development, and to prevent toner at the developing position from being smudged. Scattering prevents "uneven delivery pitch" from occurring on the image.

Implementation form 2

In the first embodiment described above, by making the volume of the first conveying screw 55Y larger than that of the second conveying screw 56Y, the space for storing the developer in the first developer storage part 53Y is larger than that in the second developer storage part 54Y. The space for the developer is narrow. Since the space for storing the developer is narrow, the height of the developer becomes higher. As shown in FIG. 10 , the height of the developer in the first developer storage portion 53Y is higher than that in the second developer storage portion 54Y.

In order to make the height position of the developer in the first developer storage portion 53Y higher than that of the developer in the second developer storage portion 54Y, it is also possible to make the developer move faster in the first developer storage portion 53Y than in the second developer storage portion 54Y. The method that the moving speed of the developer in the developer accommodating portion 54Y is slow.

Next, a structure in which the moving speed of the developer in the first developer accommodating portion 53Y is made slower than that in the second developer accommodating portion 54Y will be described as a second embodiment. The basic structure of the printer according to the second embodiment is the same as that of the first embodiment, but the shape of the transport screw in the developing device is different. The description of the same points as those of the first embodiment will be omitted, and only the different points will be described.

The developing device 5Y which makes the conveying speed of the first conveying screw 55Y slow is set to the initial stage of the printer 100 body, the height of the developer in the first developer accommodating portion 53Y and the developer in the second developer accommodating portion 54Y are substantially the same, The amount of developer is also about the same.

In this state, if the developing device 5Y is driven, since the conveying speed of the first conveying screw 55Y is slower than that of the second conveying screw 56Y, the amount of developer passing through the first opening 59Ya is larger than the amount of developer passing through the second opening 59Yb. When the amount is large, the amount of developer in the first developer storage portion 53Y increases. When the amount of developer in the first developer storage portion 53Y increases, the height of the developer in the first developer storage portion 53Y becomes higher, and the amount of developer passing through the second opening 59Yb per unit time increases.

When the amount of developer passing through the first opening 59Ya is larger than the amount of developer passing through the second opening 59Yb, the amount of developer in the second developer storage portion 54Y decreases, and the amount of developer passing through the first opening 59Ya per unit time decreases. When the amount of developer passing through the second opening 59Yb per unit time is substantially equal to the amount of developer passing through the first opening 59Ya per unit time, the developer amounts in both developer storage portions are stabilized. In this way, when the developer amount is stabilized, the state shown in FIG. 10 will be obtained.

As described above, by making the conveying speed of the first conveying screw 55Y slower than that of the second conveying screw 56Y, the height position of the developer in the first developer accommodating portion 53Y is higher than that of the developer in the second developer accommodating portion 54Y. The agent height position is high, and it is in the state shown in FIG. 10 as in the first embodiment. In this way, even if the developer in the first developer storage portion 53Y is filled up to the upper part of the storage portion in order to stabilize the amount of developer that is sucked up by the developing roller 51Y, there will be no development in the second developer storage portion 54Y. The agent is in the state of being filled up to the upper part of the storage part.

The developer in the first developer storage portion 53Y is filled up to the upper portion of the storage portion, and the amount of developer absorbed by the developing roller 51Y is stabilized, which prevents the phenomenon of “uneven conveying pitch” on the image.

Since the developer in the second developer accommodating portion 54Y is not filled up to the upper portion of the accommodating portion, the upper portion of the second conveying screw 56Y is exposed from the surface of the developer, and in the second developer accommodating portion 54Y, The developer is sufficiently stirred, and the occurrence of an insufficiently charged developer can be prevented.

Example 4

A first specific structure in which the conveying speed of the first conveying screw 55Y is made slower than that of the second conveying screw 56Y will be described as Embodiment 4 below.

FIG. 15 is a perspective view of a first conveying screw 55Yd and a second conveying screw 56Y used in a developing device 5Y according to Embodiment 4 of the present invention. As shown in FIG. 15 , the pitch width of the blades wound around the shaft portion of the first conveyance screw 55Yd for the developing device 5Y is narrower than that of the second conveyance screw 56Y. If the pitch width of the conveyance screw is narrowed, the distance for conveying the developer during one revolution of the conveyance screw becomes shorter. Therefore, when the first conveying screw 55Yd and the second conveying screw 56Y rotate at the same rotation speed, the conveying speed of the first conveying screw 55Yd is slower than that of the second conveying screw 56Y.

As described above, the pitch width of the blades of the first conveying screw 55Y is narrower than that of the second conveying screw 56Y, so that the conveying speed of the first conveying screw 55Y can be made slower than that of the second conveying screw 56Y. As shown in FIG. 10 , the developer level in the first developer storage portion 53Y is higher than the developer level in the second developer storage portion 54Y. In this way, it is possible to prevent generation of insufficiently charged developer, prevent toner from scattering, and prevent "conveyance pitch unevenness" from occurring on the image.

Example 5

Next, a second specific structure in which the conveying speed of the first conveying screw 55Y is made slower than that of the second conveying screw 56Y will be described as Embodiment 5.

FIG. 16 is a perspective view of a first conveying screw 55Ye and a second conveying screw 56Y used in a developing device 5Y according to Embodiment 5 of the present invention. As shown in FIG. 16 , the blade portion of the first conveying screw 55Ye for the developing device 5Y is provided with a cutout 91 . Since the slits are provided on the conveying screw, a part of the developer pushed by the blades of the conveying screw and moved in the axial direction of the conveying screw is dropped at the slits, and the conveying efficiency is lowered. Therefore, when the first conveying screw 55Ye and the second conveying screw 56Y rotate at the same rotation speed, the conveying speed of the first conveying screw 55Ye is slower than that of the second conveying screw 56Y.

As described above, by providing the notch 91 in the blade portion of the first conveying screw 55Ye, the conveying speed of the first conveying screw 55Y can be made slower than that of the second conveying screw 56Y. As shown in FIG. 10 , the developer level in the first developer storage portion 53Y is higher than the developer level in the second developer storage portion 54Y. In this way, it is possible to prevent generation of insufficiently charged developer, prevent toner from scattering, and prevent "conveyance pitch unevenness" from occurring on the image.

Example 6

A third specific structure in which the conveying speed of the first conveying screw 55Y is made slower than that of the second conveying screw 56Y will be described as Embodiment 6.

Fig. 17 is a perspective view of a first conveying screw 55Yf and a second conveying screw 56Y used in a developing device 5Y according to Embodiment 6 of the present invention. As shown in FIG. 17, a rib 92, which is a plate-like member parallel to the axial direction, is provided on the shaft portion of the first conveying screw 55Yf for the developing device 5Y. Since the ribs 92 are provided on the conveying screw, resistance is generated to the developer which is pushed by the blades of the conveying screw and moves in the axial direction of the conveying screw, and the conveying efficiency is reduced. Therefore, when the first conveying screw 55Yf and the second conveying screw 56Y rotate at the same rotation speed, the conveying speed of the first conveying screw 55Yf is slower than that of the second conveying screw 56Y.

As described above, by providing the rib 92 on the conveying screw, the conveying speed of the first conveying screw 55Y can be made slower than that of the second conveying screw 56Y. As shown in FIG. 10 , the developer level in the first developer storage portion 53Y is higher than the developer level in the second developer storage portion 54Y. In this way, it is possible to prevent generation of insufficiently charged developer, prevent toner from scattering, and prevent "conveyance pitch unevenness" from occurring on the image.

In Embodiments 4 to 6, the yellow developing device 5Y was used. The developing devices 5M, 5C, and 5K using other colors are the same as the developing device 5Y except for the toner color. Therefore, the conveying screws described in the above-mentioned Embodiments 4-6 can also be applied to the developing devices 5M, 5C, 5K.

The structures of the above-mentioned embodiments 4 and 6 not only make the conveying speed of the first conveying screw 55Y slow, but also make the volume of the first conveying screw 55Y larger than that of the second conveying screw 56Y. In this way, the same effect as that of the first embodiment can also be obtained. .

As described above, according to the developing device 5Y of Embodiment 2, by making the conveying speed of the first conveying screw 55Y slower than that of the second conveying screw 56Y, the developer in the first developer accommodating portion 53Y is supplied to the developing roller 51Y. The height is higher than the height of the developer inside the second developer storage portion 54Y that receives toner replenishment from above. In this way, even if the developer in the first developer accommodating portion 53Y is filled up to the upper part of the accommodating portion in order to stabilize the amount of developer that is sucked up by the developing roller 51Y, the developer in the second developer accommodating portion 54Y will not Stuffed to the upper part of the storage part. By making the developer in the first developer storage portion 53Y fill up to the upper portion of the storage portion, it is possible to prevent the “conveyance pitch unevenness” from occurring on the image. Furthermore, the developer in the second developer storage portion 54Y does not fill up the upper portion of the storage portion, so the upper portion of the second conveyance screw 56Y is exposed from the developer surface, and the developer in the second developer storage portion 54Y Stirring can be sufficiently obtained, and the occurrence of an insufficiently charged developer can be prevented. In this way, by using the developing device 5Y, it is possible to prevent background smearing and toner scattering caused by insufficiently charged developer, and to prevent the phenomenon of "uneven conveyance pitch" from occurring on the image.

By making the pitch width of the blades of the first conveyance screw 55Yd for the developing device 5Y narrower than that of the second conveyance screw 56Y, the conveyance speed of the first conveyance screw 55Y can be made slower than that of the second conveyance screw 56Y.

By providing the blade portion of the first conveyance screw 55Ye for the developing device 5Y with the cutout 91, the conveyance speed of the first conveyance screw 55Y can be made slower than that of the second conveyance screw 56Y.

By providing the rib 92 on the shaft portion of the first conveyance screw 55Yf for the developing device 5Y, the conveyance speed of the first conveyance screw 55Y can be made slower than that of the second conveyance screw 56Y.

Even if the developer in the first developer storage portion 53Y fills up to the upper portion of the storage portion, since the conveyance speed of the first conveyance screw 55Y is slow, the load applied to the first conveyance screw 55Y can be reduced.

Modification 2

In Embodiment 2, by making the conveying speed of the first conveying screw 55Y slower than that of the second conveying screw 56Y, the moving speed of the developer in the first developer accommodating portion 53Y is faster than that of the developer in the second developer accommodating portion 54Y. The agent moves slowly. Since the moving speed of the developer is slow, the height of the developer becomes higher. As shown in FIG. 10 , the height of the developer in the first developer storage portion 53Y is higher than that in the second developer storage portion 54Y. As a structure for making the developer moving speed in the first developer storage portion 53Y slower than the developer moving speed in the second developer storage portion 54Y, it is not limited to the structures listed above.

Next, the configuration of Modification 2, which makes the developer moving speed in the first developer accommodating portion 53Y faster than The moving speed of the developer in the second developer storage portion 54Y is slow.

FIG. 18 is a cross-sectional view of a developing device 5Y viewed from above according to Modification 2 of the present invention. As shown in FIG. 18 , a developer conveyance suppressing member 53Yb for suppressing conveyance of the developer is provided inside the first developer accommodating portion 53Y. The developer transport suppressing member 53Yb is a soft film-shaped member made of resin such as polyethylene. Since the developer transport suppressing member 53Yb is soft and easily deformed, it contacts the first transport screw 55Y and is easily deformed without hindering the rotation of the first transport screw 55Y. On the other hand, the movement of the developer particles is hindered to some extent, and the transport efficiency of the developer is lowered. Therefore, when the first conveying screw 55Y and the second conveying screw 56Y rotate at the same speed, the conveying speed of the first conveying screw 55Y is slower than that of the second conveying screw 56Y.

As described above, the conveyance speed of the first conveyance screw 55Y is made slower than that of the second conveyance screw 56Y by providing the developer conveyance suppressing member 53Yb for suppressing conveyance of the developer in the first developer accommodating portion 53Y. As shown in FIG. 10 , it is possible to make the height of the developer in the first developer storage portion 53Y higher than the height of the developer in the second developer storage portion 54Y.

The developer in the developing device 5Y is in the state shown in FIG. 10. Even if the developer in the first developer storage portion 53Y is filled up to the upper part of the storage portion in order to stabilize the amount of developer that is sucked up by the developing roller 51Y, the second The developer in the developer storage portion 54Y does not fill up the upper portion of the storage portion.

By making the developer in the first developer storage portion 53Y fill up to the upper portion of the storage portion, the amount of developer that the developing roller 51Y can absorb is stabilized, and the phenomenon of “uneven conveying pitch” on the image can be prevented.

Furthermore, the developer in the second developer storage portion 54Y does not fill up the upper portion of the storage portion, so the upper portion of the second conveyance screw 56Y is exposed from the developer surface, and the developer in the second developer storage portion 54Y Stirring can be sufficiently obtained, and the occurrence of an insufficiently charged developer can be prevented.

In this way, in the developing device 5Y of the above-mentioned modification 2, as in the above-mentioned second embodiment, it is possible to prevent image background smearing caused by the developer having an insufficient charge amount being used for development, and to prevent the occurrence of toner at the developing position. Scattering prevents "uneven delivery pitch" from occurring on the image.

Modification 3

As a configuration to make the conveying speed of the first conveying screw 55Y slower than that of the second conveying screw 56Y, it can be realized by slowing down the conveying speed of the first conveying screw 55Y. When the driving source of the first conveying screw 55Y and the second conveying screw 56Y is a motor, it can be realized by, for example, changing the transmission gear ratio of the two conveying screws. When the first conveying screw 55Y and the second conveying screw 56Y are respectively provided with driving motors, for example, the number of revolutions of the driving motor of the first conveying screw 55Y can be slowed down.

In this configuration, since only the rotational speeds of the two conveying augers are made different, the shapes of the two conveying augers are substantially the same.

As described above, by making the rotation speed of the first conveying screw 55Y slower than that of the second conveying screw 56Y, the conveying speed of the first conveying screw 55Y can be made slower than that of the second conveying screw 56Y. As shown in FIG. 10 , it is possible to make the height of the developer in the first developer storage portion 53Y higher than the height of the developer in the second developer storage portion 54Y.

The developer in the developing device 5Y is in the state shown in FIG. 10. Even if the developer in the first developer storage portion 53Y is filled up to the upper part of the storage portion in order to stabilize the amount of developer that is sucked up by the developing roller 51Y, the second The developer in the developer storage portion 54Y does not fill up the upper portion of the storage portion.

By making the developer in the first developer storage portion 53Y fill up to the upper portion of the storage portion, the amount of developer that the developing roller 51Y can absorb is stabilized, and the phenomenon of “uneven conveying pitch” on the image can be prevented.

Furthermore, the developer in the second developer storage portion 54Y does not fill up the upper portion of the storage portion, so the upper portion of the second conveyance screw 56Y is exposed from the developer surface, and the developer in the second developer storage portion 54Y Stirring can be sufficiently obtained, and the occurrence of an insufficiently charged developer can be prevented.

In this manner, in the developing device 5Y of the third modification, as in the second embodiment, it is possible to prevent image background smearing caused by the use of developer with an insufficiently charged amount for development, and to prevent the occurrence of toner contamination at the developing position. Scattering prevents "uneven delivery pitch" from occurring on the image.

As shown in the developing devices of Embodiment 1 and Embodiment 2 above, the height of the developer in the first developer storage portion 53Y is higher than the height of the developer in the second developer storage portion 54Y, which is the volume that passes through the two conveying screws. caused by poor or poor shipping speed. As the developer agitating and conveying member other than the spiral, for example, a conveying coil made of resin or metal can be used. In the case of using a conveying coil, the conveying coil corresponding to the first conveying screw can achieve a slow conveying speed by making its wire diameter thick and its rotation speed slow. It is also possible to make its coil pitch small. A method such as making the axis thicker can be used for the transport coil having an axis by brazing or the like. If a developing device using such a conveying coil is used, as in Embodiments 1 and 2 above, it is possible to prevent image background staining caused by the use of insufficiently charged developer for development, and to prevent the occurrence of toner at the developing position. Scattering prevents "uneven delivery pitch" from occurring on the image.

The embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the above-described embodiments. Various changes can be made within the scope of the technical thought of the present invention, and they all belong to the protection scope of the present invention.

For example, in the image forming apparatus described above, the toner images formed on the respective image carriers are transferred onto the transfer material made of an intermediate transfer belt, but the present invention is also applicable to directly transferring the toner images formed An image forming apparatus in which the toner images on the respective image carriers are superimposed and transferred onto the recording medium. In this case, the recording medium constitutes a transfer material, and the toner images of different colors formed on the respective image carriers are transferred to the transfer material.

In addition, in the above-mentioned embodiment, the image forming apparatus provided with four process cartridges was exemplified, but the present invention can also be applied to an image forming apparatus provided with only one process cartridge.

In the above embodiments, the image carrier is included in the process cartridge, but the present invention is not limited thereto, and may include only the developing device instead of the image carrier. In this case, the image carrier can be accommodated in another unit, and can be attached to and detached from the device body.

Claims (11)

1. developing apparatus comprises:

Developer mounting body, the mounting developer;

Developer is taken in by developer receptacle portion, is provided with peristome;

First developer stirs and transports parts, by revolution, stirs the developer that transports in this developer receptacle portion, with the described developer mounting of developer replenishing body;

Second developer stirs and transports parts, by revolution, stirs the developer in this developer receptacle portion, transports developer towards stirring the developer carriage direction reverse direction that transports parts with described first developer;

Partition wall, stir at described first developer and to transport parts and second developer and stir and transport between the parts, transport the revolving shaft direction both ends that parts are transported in parts or the stirring of second developer along the stirring of first developer, become the peristome that developer can pass through;

Wherein, among the space that this partition wall is separated, be provided with first developer and stir developer aspect ratio in the space of transporting parts and be provided with the stirring of second developer and transport developer height height in the space of parts.

2. according to the developing apparatus of record in the claim 1, it is characterized in that it is big that volume ratio second developer that makes described first developer stirring transport parts stirs the volume that transports parts.

3. according to the developing apparatus of putting down in writing in the claim 2, it is characterized in that, described first developer stirs and transports parts and second developer and stir and transport parts and be made of axial region and blade part, and it is big that first developer stirs the axial region diameter of axle that the axial region diameter of axle that transports parts transports parts than the stirring of second developer.

4. according to the developing apparatus of putting down in writing in the claim 2, it is characterized in that, described first developer stirs and transports parts and second developer and stir and transport parts and be made of axial region and blade part, and it is thick that first developer stirs the blade part that the blade part that transports parts transports parts than the stirring of second developer.

5. according to the developing apparatus of putting down in writing in the claim 2, it is characterized in that, described first developer stirs and transports parts and second developer and stir and transport parts and be made of axial region and blade part, first developer stirs the blade part that transports parts and is provided with some blades, described some blades have same pitch, and it is many that the number of blade that parts are transported in the stirring of first developer is transported parts than the stirring of second developer.

6. according to the developing apparatus of putting down in writing in the claim 1, it is characterized in that, described first developer stirs and transports parts and second developer and stir and transport parts and be made of axial region and blade part, and first developer stirs the developer travelling speed of transporting parts, and to stir the developer travelling speed of transporting parts than second developer slow.

7. according to the developing apparatus of record in the claim 6, it is characterized in that the pitch that described first developer stirs the blade part that transports parts is littler than the pitch that second developer stirs the blade part that transports parts.

8. according to the developing apparatus of record in the claim 6, it is characterized in that, stir the blade part that transports parts at described first developer and have otch.

9. according to the developing apparatus of record in the claim 6, it is characterized in that, stir to transport to be provided with on the parts at described first developer and stir the parallel plate-shaped member of axial region that transports parts with described first developer.

10. cartridge processing comprises at least:

Picture mounting body;

The development means are to the image development on the described picture mounting body;

Described picture mounting body and the supporting of development means are one, and the image forming device body loading and unloading freely relatively; It is characterized in that:

Use among the described claim 1-9 any described developing apparatus as described development means.

11. an image processing system comprises:

Charging facility makes that picture mounting surface is charged;

Sub-image forms means, is used for forming electrostatic latent image on described picture mounting body;

The development means to described latent electrostatic image developing, make it become the toner picture; It is characterized in that:

Use the cartridge processing described in any described developing apparatus among the described claim 1-9 or the described claim 10, as described development means.

Images