JP2006091037A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant application device by which cleaning nature is continued to be maintained over a long period even in a small process cartridge by stably maintaining an application amount of solid lubricant over a long period by a simple and low-cost method and an image forming apparatus having the same. <P>SOLUTION: Pawl-like projected parts 10-1 as shown in Figure are provided at several parts of a part of a casing 10. The projected parts 10-1 contact the upper part of the solid lubricant 8 and the solid lubricant 8 serves as resistance to welding pressure F to be welded to a lubricant application roller by a spring 9. When the process cartridge is continued to be used at this state, variation of the welding force in passage of time is compensated for the resistance R, difference in the welding force between the initial stage and near the life of the solid lubricant decreases and change of the application amount of the lubricant in lapse of time is suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a toner density control device in an image forming apparatus, and more particularly to a good toner replenishment control device in an image forming apparatus such as a copying machine, a printer, and a facsimile machine using an electrophotographic system.

In recent years, small particle size toners such as polymerized toners are widely used in image forming apparatuses in order to improve image quality. However, these small particle size toners have a problem that it is difficult to clean the toner remaining on the photoreceptor after the image is transferred onto the transfer paper by the photoreceptor cleaning means.
As a means for solving the above problem, there is used a method in which a lubricant is applied to a photosensitive member and the friction coefficient of the photosensitive member is lowered, thereby preventing chattering of a cleaning blade as a cleaning unit and improving a toner cleaning property.
As a method of applying the lubricant, a method of applying a solid lubricant by applying pressure to the applying means with a spring as in Patent Document 1 and Patent Document 2 has been proposed. (Figure 2)

As described above, when a lubricant is applied in order to improve the cleaning property, it is desirable that the application amount be continuously applied as much as possible. When the coating amount is small, the reduction in the frictional force of the photoreceptor is reduced, and the effect of improving the cleaning property is diminished. On the other hand, if the coating amount is too large, the consumption amount becomes excessive and the predetermined lubricant is used up quickly. In particular, in a small apparatus such as a process cartridge, the amount of lubricant that can be mounted is limited, so it is desirable to keep the application amount to the minimum amount that can maintain the function.
However, in a device that applies a solid lubricant by applying pressure with a spring, the amount of lubricant applied is the same as the amount of lubricant applied. There was a problem of decreasing. (Figure 3)
As a method for regulating the amount of lubricant applied, methods such as Patent Document 1 and Patent Document 2 in which the applied pressure is changed by a cam or solenoid have been proposed, but these are used for small process cartridges because the apparatus becomes complicated. It is not suitable to do. In addition, the cost increases.

JP-A-2002-24487 JP 2000-231298 A

The present invention provides a lubricant application device that maintains a cleanability for a long time even in a small process cartridge by stably maintaining the coating amount of the solid lubricant for a long time by a simple and low-cost method, and It is an object of the present invention to provide an image forming apparatus including the above.

As means for solving the above problems, the present invention has the following features.
In the lubricant application device according to claim 1, in the lubricant application device for applying a solid lubricant, which is pressurized to an application device such as a brush roller by a spring, to the photoreceptor by the application means in the housing. A convex portion is provided on the inner wall of the solid lubricant housing so that the solid lubricant partially contacts the inner wall.
The lubricant application device according to claim 2, further comprising: a convex portion provided on the inner side of the casing, wherein the solid lubricant is in an initial use state, and the spring pressing direction of the outer periphery of the solid lubricant is It is characterized by being located on the spring side.
4. The process cartridge according to claim 3, wherein the electrophotographic photosensitive member and at least one of a charging unit, a developing unit, and a cleaning unit are integrally configured to be detachable from the image forming apparatus main body. The process cartridge includes the lubricant application device according to claim 1 or 2.
According to a fourth aspect of the present invention, the image forming apparatus includes the process cartridge according to the third aspect.
According to a fifth aspect of the present invention, the image forming apparatus includes the lubricant application device according to the first or second aspect.
The image forming apparatus according to claim 6 is further characterized in that the toner used is a polymerized toner.

As described above, due to the means for solving the above problems, it is difficult to clean from the surface of the photoreceptor with the lubricant coating apparatus of the present invention, and even in an image forming apparatus using a polymerized toner in which lubricant coating is indispensable. Lubricant application can be performed stably at a low cost.
Further, the process cartridge provided with the lubricant application device of the present invention is advantageous in terms of maintenance, and by simply replacing the process cartridge, it is possible to quickly recover the failure caused by the part or device, and shorten the service time. Can be planned. Furthermore, making the electrophotographic photosensitive member easy to clean greatly contributes to the extension of the life of the process cartridge.

The configuration of the present invention will be described below. FIG. 1 is a schematic diagram of an image forming apparatus.
In the apparatus, a photosensitive member 1, a developing roller 2, a charging roller 3, a charging roller cleaning member 4, and a photosensitive member cleaning device 5 are arranged.
The toner image visualized on the photoreceptor 1 by a known process is transferred onto paper by the transfer roller 6 and fixed by a fixing device (not shown).
After the transfer process, a solid lubricant 8 such as zinc stearate is applied to the lubricant application roller 7 by a spring 9 by a lubricant application roller 7 such as a brush roller, and the toner in the cleaning device 5 which is the next process. Assists removal.
Most of the transfer residual toner on the photosensitive member is removed from the surface of the photosensitive member by the photosensitive member cleaning device 5, but a small amount of toner that cannot be completely removed adheres to the charging roller 3, and further, by the charging cleaning member 4. It is removed from the surface of the charging roller 3.
When passing through the nip between the transfer roller 6 and the photoreceptor 1, a part of the paper dust adheres on the photoreceptor. They are removed by the photoconductor cleaning device 5, but some of them pass through the cleaning means and adhere to and accumulate on the surface of the charging roller 3. These paper dusts are also removed from the surface of the charging roller 3 by the charging cleaning member 4 in the same manner as the toner.

As shown in FIG. 2, the solid lubricant application part has two springs 9 fixed to the inside of a housing 10 in which the solid lubricant 8 is slidable. Is applied to the lubricant application roller.
If the process cartridge is continuously used in this state, the contact portion of the solid lubricant 8 with the lubricant application roller 7 is gradually scraped. Then, as shown in FIG. 3, the spring 9 is in the extended state as compared with FIG. 2, so that the urging force against the solid lubricant 8 is weakened, and the lubricant application roller 7
As a result, the amount of the lubricant applied to the photosensitive member 1 is reduced.

  In the present invention, a part of the housing 10 is provided with claw-like convex portions 10-1 as shown in FIG. The convex portion 10-1 is in contact with the upper part of the solid lubricant 8 as in claim 2, and the solid lubricant 8 becomes a resistance force against the pressure F applied to the lubricant application roller by the spring 9. Yes. That is, a resistance force R due to the frictional force of the convex portion is applied to the initial pressure F1 by the spring, and the pressure F of the solid lubricant 8 against the lubricant application roller 7 is F1-R.

If the process cartridge is continuously used in this state, the contact portion of the solid lubricant 8 with the lubricant application roller 7 is gradually scraped. Then, as shown in FIG. 5, when the upper end portion is scraped to a position where the upper end portion comes to a position where it is in close contact with the convex portion on the nail, the pressure applied by the spring moves the solid lubricant from the initial pressure F1. F2 is lowered by the distance. In this state, the pressure F applied to the lubricant application roller of the solid lubricant 8 becomes F2-R. When the use is further continued, as shown in FIG. 6, the solid lubricant is finally separated from the claw portion 10-1. At this time, as a matter of course, the pressure applied to the lubricant application roller of the solid lubricant 8 is eliminated by the resistance force R caused by the claw portion 10-1, so that if the spring pressure at this position is F3, only the term F3 is applied. Become.

When the use is further continued, the solid lubricant is further scraped, and the pressure applied by the spring is F4 as shown in FIG. 7, and the pressure applied to the lubricant application roller of the solid lubricant 8 is also F4.
That is, when there is no nail | claw part 10-1, the applied pressure with respect to the lubricant application roller of the solid lubricant 8 is F '= F1->F2->F3-> F4.
F = F1-R → F2-R → F3 → F4 by providing the claw portion 10-1.
Then, the change in the applied pressure over time is corrected by the resistance force R, and the difference in applied pressure between the initial stage and the life of the process cartridge is reduced.

Since the mechanism of the present invention is simple and small, it can be used more effectively in a process cartridge that requires a particularly small size.
In addition, since the toner is spherical and has a small particle size, the toner rotates between the cleaning blade and the photoconductor, and enters the gap, so that it is difficult to clean from the surface of the photoconductor, and a polymerized toner that is indispensable for lubricant application Also in an image forming apparatus using the above, it is possible to stably apply a lubricant at low cost.

An image forming apparatus including the process cartridge or the lubricant application device of the present invention will be described.
FIG. 8 is a schematic diagram showing the configuration of an embodiment of the image forming apparatus according to the present invention. In the figure, reference numeral 100 is a copying apparatus main body, 200 is a paper feed table on which the copying apparatus is placed, 300 is a scanner mounted on the copying apparatus main body 100, and 400 is an automatic document feeder (ADF) mounted thereon.
The copying apparatus main body 100 has a tandem type in which four image forming units 18 each having various units for performing an electrophotographic process such as charging, developing, and cleaning are arranged in parallel around a photosensitive member 40 as a latent image carrier. An image forming apparatus 20 is provided. Above the tandem type image forming apparatus 20, there is provided an exposure apparatus 21 that exposes the photoreceptor 40 with laser light based on image information to form a latent image. Further, an intermediate transfer belt 12 made of an endless belt member is provided at a position facing each photoconductor 40 of the tandem type image forming apparatus 20. A primary transfer unit 62 that transfers the toner images of the respective colors formed on the photoconductor 40 to the intermediate transfer belt 12 is disposed at a position facing the photoconductor 40 via the intermediate transfer belt 12.

A secondary transfer device 22 that collectively transfers the toner images superimposed on the intermediate transfer belt 12 onto transfer paper conveyed from the paper feed table 200 is disposed below the intermediate transfer belt 12. The secondary transfer device 22 is configured by spanning a secondary transfer belt 24 that is an endless belt between two rollers 23, and is pressed against the support roller 16 via the intermediate transfer belt 12. 12 is transferred to the transfer paper. A fixing device 25 for fixing the image on the transfer paper is provided beside the secondary transfer device 22.
The secondary transfer device 22 described above also has a sheet transport function for transporting the transfer paper after image transfer to the fixing device 25. Of course, a transfer roller or a non-contact charger may be arranged as the secondary transfer device 22, and in such a case, it is difficult to provide this sheet conveyance function together.
In the illustrated example, a reversing device 28 for reversing the transfer paper so as to record images on both sides of the transfer paper is provided below the secondary transfer device 22 and the fixing device 25 in parallel with the tandem image forming device 20 described above. .

The developing device 11 of the image forming unit 18 uses a developer containing the above toner. In the developing device 11, the developer carrying member carries and conveys the developer, and an alternating electric field is applied at a position facing the photoconductor 40 to develop the latent image on the photoconductor 40. By applying the alternating electric field, the developer is activated, the toner charge amount distribution can be narrowed, and the developability can be improved.
Further, a process cartridge that is integrally supported with the photosensitive member 40 and is detachably formed on the main body of the image forming apparatus can be obtained. In addition, the process cartridge may include a charging unit, a developing device, and a cleaning unit.

The operation of the image forming apparatus is as follows.
First, a document is set on the document table 30 of the automatic document feeder 400, or the automatic document feeder 400 is opened and a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed. Hold it down.
When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the other contact glass 32. At that time, the scanner 300 is immediately driven to travel the first traveling body 33 and the second traveling body 34. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34 and reflects by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.

  When a start switch (not shown) is pressed, one of the support rollers 14, 15, 16 is rotated by a drive motor (not shown), the other two support rollers are driven to rotate, and the intermediate transfer belt 12 is rotated and conveyed. To do. At the same time, the individual image forming means 18 rotates the photoconductors 40 to form black, yellow, magenta, and cyan monochrome images on the photoconductors 40, respectively. Then, along with the conveyance of the intermediate transfer belt 12, the single color images are sequentially transferred to form a composite color image on the intermediate transfer belt 12.

On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and the sheet is fed out from one of the paper feed cassettes 44 provided in multiple stages in the paper bank 43, and the separation roller 45. Then, the sheets are separated one by one into the paper feed path 46, transported by the transport roller 47, guided to the paper feed path 48 in the copying machine main body 100, and abutted against the registration roller 49 and stopped.
Alternatively, the sheet feed roller 50 is rotated to feed out the sheets on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped.
Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer belt 12, the sheet is fed between the intermediate transfer belt 12 and the secondary transfer device 22, and is transferred by the secondary transfer device 22. A color image is recorded on the sheet.

The image-transferred sheet is conveyed by the secondary transfer device 22 and sent to the fixing device 25. The fixing device 25 applies heat and pressure to fix the transferred image, and then the switching roller 55 is used to switch the discharge image. The paper is discharged at 56 and stacked on the paper discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and the image is recorded also on the back surface, and then discharged onto the discharge tray 57 by the discharge roller 56.
On the other hand, the intermediate transfer belt 12 after the image transfer is removed by the intermediate transfer belt cleaning device 17 to remove residual toner remaining on the intermediate transfer belt 12 after the image transfer, so that the tandem image forming device 20 can prepare for the image formation again.

1 is a schematic view of an image forming unit showing an embodiment of the present invention. It is a schematic block diagram of a solid lubricant application apparatus. It is a figure which shows the state in which the solid lubricant of FIG. 2 was used. 1 is a schematic configuration diagram of a solid lubricant application device in which a claw-like convex part is provided in a part of a housing, and a pressing force F1 by a spring 9 and a frictional resistance R of the convex part act on the solid lubricant 8. FIG. ing. FIG. 5 is a diagram showing a state in which the solid lubricant of FIG. 4 is used, and the solid lubricant 8 is subjected to a pressing force F2 by a spring 9 and a frictional resistance R of a convex portion. FIG. 6 is a diagram showing a state in which the solid lubricant of FIG. 5 is further used, and only the pressing force F <b> 3 by the spring 9 is acting on the solid lubricant 8. FIG. 7 is a diagram showing a state in which the solid lubricant of FIG. 6 is further used, and only the pressing force F <b> 4 by the spring 9 is acting on the solid lubricant 8. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Developing roller 3 Charging roller 4 Charging roller cleaning member 5 Photoconductor cleaning device 6 Transfer roller 7 Lubricant application roller 8 Solid lubricant 9 Spring 10 Housing 10-1 Convex part 11 Developing device 12 Intermediate transfer belt 16 Support Roller 18 Image forming means 20 Tandem image forming device 21 Exposure device 22 Secondary transfer device 24 Secondary transfer belt 25 Fixing device 28 Reversing device 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 40 Photoconductor (latent image carrier)
43 Paper bank 44 Paper feed cassette 45 Separation roller 46 Paper feed path 47 Transport roller 48 Paper feed path 49 Registration roller 50 Paper feed roller 51 Manual feed tray 52 Separating roller 55 Switching claw 56 Discharge roller 57 Paper discharge tray 62 Primary transfer means 100 Copy Device main body 200 Paper feed table 300 Scanner 400 Automatic document feeder

Claims (6)

In the casing, in the lubricant application device that applies the solid lubricant pressurized to the application device such as a brush roller by a spring to the photoreceptor by the application means,
A lubricant coating device, wherein a convex portion is provided on an inner wall of the solid lubricant casing so that the solid lubricant partially contacts the inner wall. In the lubricant application device according to claim 1,
The convex portion provided on the inner side of the casing is located on the spring side in the pressurizing direction of the outer peripheral spring of the solid lubricant when the solid lubricant is in an initial use state. Coating device. In a process cartridge in which an electrophotographic photosensitive member and at least one of a charging unit, a developing unit, and a cleaning unit are integrally configured to be detachable from the image forming apparatus main body,
The process cartridge includes the lubricant application device according to claim 1. An image forming apparatus comprising the process cartridge according to claim 3. An image forming apparatus comprising the lubricant application device according to claim 1. The image forming apparatus according to claim 4 or 5, wherein:
In the image forming apparatus, the toner used is a polymerized toner.

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