JP2008129468A - Image forming apparatus and process cartridge - Google Patents

Abstract

An image forming apparatus and a process cartridge having a configuration capable of driving a charging roller cleaner in a space-saving manner are provided.
In an image forming apparatus for developing a latent image on an image carrier, transferring the image onto a transfer paper, and fixing the transferred image on the transfer paper, a charging roller for charging the surface of the image carrier. The charging roller cleaner 18 is driven by the charging roller 15 and the gear 23a for driving the charging roller cleaner provided on the charging roller 15 is connected to the image roller. It is integrated with a gap regulating member 23 for providing a gap between the carrier 10 and the charging roller 15.
[Selection] Figure 3

Description

  The present invention relates to an electrophotographic system such as a copying machine, a printer, a facsimile machine, or a combination machine thereof, provided with a charging roller for charging a photoreceptor for image formation and a charging roller cleaner for removing dirt on the charging roller. The present invention relates to an image forming apparatus and a process cartridge.

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a printer, or a facsimile apparatus provided with a charging roller for charging a photosensitive member for image formation and a charging roller cleaner for removing dirt on the charging roller, the charging roller cleaner is a driving source. In many cases, the charging roller is rotated around the charging roller without being held, and the charging roller cleaner is simply pressed against the charging roller by its own weight or a spring (see, for example, Patent Documents 1 to 4).
FIG. 6 is a schematic front view showing a conventional charging roller cleaner. FIG. 7 is an enlarged perspective view showing one end of the conventional charging roller cleaner of FIG. 6 and 7 show details of the conventional charging roller 15 and charging roller cleaner 18.

Both ends of the charging roller 15 are rotatably supported by bearings 21, and the bearings 21 are pressed against the photoconductor 10 by springs (not shown). There are gap rollers 23 at both ends of the charging roller 15, and the gap rollers 23 abut against the photoreceptor 10, thereby providing a gap between the photoreceptor 10 and the charging roller 15. The charging roller 15 is driven by charging roller driving gears 19 and 20 and rotates with respect to the photosensitive member 10.
Next, similarly to the charging roller 15, the charging roller cleaner 18 is supported by a bearing 22 so that both ends of the charging roller cleaner 18 can rotate. The bearing 22 is pressed against the charging roller 15 by a spring (not shown), whereby the charging roller cleaner 18 is moved. It is in contact with the charging roller 15.
A brush roller is known as the charging roller cleaner 18, and a resin foam is known as the material thereof. Conventionally, the charging roller cleaner 18 has no particular drive source, and has simply been rotated by the frictional force with the charging roller 15.
JP-A-5-297690 JP 2002-221883 A JP 2004-361916 A Japanese Patent Application Laid-Open No. 08-062948

However, in the case of such a resin charging roller, the surface of the charging roller is very smooth, and if the charging roller cleaner is simply pressed against the charging roller by its own weight or a spring, the charging roller cleaner is placed on the charging roller. On the other hand, uneven rotation may occur due to slipping. In particular, if the charging roller cleaner causes a rotation failure, the charging roller dirt may be pressed against the charging roller, which may adversely affect the charging roller cleaner.
Therefore, it is desirable to stabilize the rotation of the charging roller cleaner. However, since the process cartridge has been downsized in recent years as the size of the apparatus has been reduced, a configuration in which the driving of the charging roller cleaner is space-saving is also required. .
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus and a process cartridge having a configuration capable of driving a charging roller cleaner in a space-saving manner.

In order to solve the above problems, the invention according to claim 1 is an image forming apparatus for developing a latent image on an image carrier, transferring the image to a transfer sheet, and fixing the transfer image on the transfer sheet. A charging roller cleaner that removes dirt on the surface of the charging roller that charges the surface of the image carrier is provided. The charging roller cleaner is gear-driven by the charging roller, and a gear that drives the charging roller cleaner provided on the charging roller. Is characterized by an image forming apparatus integrated with a gap regulating member for providing a gap between the image carrier and the charging roller.
According to a second aspect of the present invention, the gap forming member integrated with the charging roller cleaner driving gear is provided on both sides of the charging roller. To do.
According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein the shaft diameter of the bearing sliding portion of the charging roller cleaner is different on both sides.

According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects, wherein cylindrical members having a smaller diameter than the charging roller cleaner are provided at both ends of the charging roller cleaner. To do.
The invention according to claim 5 is characterized in that the cylindrical member provided at both ends of the charging roller cleaner is made of resin.
According to a sixth aspect of the invention, there is provided the image forming apparatus according to any one of the first to fifth aspects, wherein the charging roller and the bearing of the charging roller cleaner are integrated.
According to a seventh aspect of the invention, the image forming apparatus according to any one of the first to sixth aspects is characterized in that the charging roller cleaner is a brush roller.
The invention according to claim 8 is the image forming apparatus according to any one of claims 1 to 7, wherein a material of the charging roller cleaner is a foamable resin.

According to a ninth aspect of the present invention, there is provided a process cartridge which supports at least one unit selected from an image carrier, a charging unit, a developing unit, and a cleaning unit, and is detachable from the main body of the image forming apparatus. A process cartridge including the charging roller and the charging roller cleaner according to any one of 1 to 8 is characterized.
An image forming apparatus according to a tenth aspect of the invention includes the process cartridge according to the ninth aspect.

  According to the present invention, by integrating the gear for driving the charging roller cleaner with the gap roller of the charging roller, a space-saving configuration can be achieved and the number of parts can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of a color image forming apparatus to which the present invention is applied. FIG. 2 is a sectional view showing a process cartridge which is the image station of FIG.
First, a process for obtaining a color image will be described with reference to FIGS. In FIG. 1, the color image forming apparatus A includes process cartridges 11a to 11d which are four image stations.
Each image station has a photosensitive drum 10 as an image carrier, and has a dedicated photosensitive member cleaning means 14, a charging roller (charging means) 15, a developing device 16, and a charging roller cleaner 18 around the photosensitive drum. Yes.
The toner bottle 2 for replenishing toner is filled with yellow, cyan, magenta, and black toner from the left in FIG. 1, and from there to a developing device 16 for each color by a predetermined replenishment amount through a conveyance path (not shown). To be replenished.
When the leading edge of the transfer paper 8 is fed by the paper feed roller 7 and reaches the registration roller 6, it is detected by a sensor (not shown). And conveyed to the nip of the intermediate transfer belt 1.
The photosensitive drum 10 uniformly charged in advance by the charging roller 15 is exposed and scanned by the laser beam from the writing unit 9 to form an electrostatic latent image on the photosensitive drum 10. Each electrostatic latent image is developed by the developing device 16 for each color, whereby yellow, cyan, magenta, and black toner images are formed on the surface of the photosensitive drum 10.

Next, a voltage is applied to the transfer roller 13, and the toner images on the respective photosensitive drums 10 are sequentially transferred onto the intermediate transfer belt 1. At this time, the image forming operation for each color is executed while shifting the timing from the upstream side toward the downstream side so that the toner image is transferred to the same position on the intermediate transfer belt 1.
The toner image formed on the intermediate transfer belt 1 is conveyed to the position of the secondary transfer roller 5 and is secondarily transferred to the transfer paper 8. The transfer paper 8 on which the toner image of each color is transferred is conveyed to the fixing unit 4 and thermally fixed, and is discharged by the paper discharge roller 3.
The residual toner on the photosensitive drum 10 is cleaned by the respective cleaning means 14, and the residual toner on the intermediate transfer belt 1 is cleaned by the cleaning means 12.
These waste toners are discharged from the process cartridge 11 to a waste toner bottle (not shown) provided in the image forming apparatus A by a waste toner conveying screw 17 in each cleaning unit.

FIG. 3 is a schematic front view showing the configuration of the charging roller and the charging roller cleaner using the embodiment of the present invention. 4 is an enlarged perspective view showing one end of the charging roller cleaner of FIG.
With reference to FIG. 3 and FIG. 4, the structure of the charging roller 15 and the charging roller cleaner 18 using the embodiment of the present invention is shown. The basic configuration is the same as that of the conventional example described above with reference to FIGS.
The charging roller 15 is rotatably supported at both ends in the axial direction by bearings 21, and the bearings 21 are pressed against the photoconductor 10 by springs (not shown). There are gap rollers 23 at both ends of the charging roller 15, and the gap rollers 23 abut on the photoreceptor 10, thereby providing a gap between the photoreceptor 10 and the charging roller 15. The charging roller 15 is driven by charging roller driving gears 19 and 20 and rotates with respect to the photosensitive member 10.

Next, similarly to the charging roller 15, the charging roller cleaner 18 is supported by bearings 22 so that both ends in the axial direction are rotatable, and the charging roller cleaner 18 is pressurized against the charging roller 15 by a spring (not shown). 18 is in contact with the charging roller 15.
In the embodiment of the present invention, a driving gear 24 is provided at the end of the charging roller cleaner 18, and a driving gear 23 a integrated with the gap roller 23 for driving the charging roller cleaner 18 is provided on the charging roller 15 side. Yes.
By arranging the gap roller 23 of the charging roller 15 and the driving gear of the charging roller cleaner 18 in an integrated manner, the charging roller cleaner 18 can be driven in the same space as in the conventional example, and space saving can be realized.
Further, if the gap roller 23a with gear is provided only on one side of the charging roller 15 (for example, the other side is only the gap roller 23 (see FIG. 6) and no gear is provided), the charging roller cleaner 18 is assembled. .

However, as shown in FIG. 3, if the same geared gap roller 23 a is provided at both ends of the charging roller 15, the charging roller cleaner 18 is not assembled and the charging roller cleaner 18 can be reversed. As a result, ease of assembly is improved.
Similarly, in order to eliminate the directionality in the assembly of the charging roller cleaner 18, the shaft diameter on both sides of the charging roller cleaner 18 is changed so that the charging roller cleaner 18 does not enter the bearing 22 when it is assembled in reverse. realizable. That is, the charging roller cleaner 18 can be prevented from being reversed.
Further, the charging roller cleaner 18 is in contact with the charging roller 15 by its own weight or biased by a spring (in this embodiment and the conventional example, since the charging roller cleaner 18 is disposed on the lower side, the spring is added. Pressure).
Therefore, if the drive roller 24 is simply provided in the charging roller cleaner 18, the distance between the charging roller 15 and the charging roller cleaner 18 is not determined, and the charging roller cleaner 18 bites into the charging roller 15 too much. There is a risk of malfunctions such as abnormal noise occurring when the bottom of the gear hits.

FIG. 5 is an enlarged perspective view showing the configuration of another embodiment of the charging roller cleaner using the embodiment of the present invention. In order to prevent the occurrence of the above-described problems, it is desirable that the distance between the charging roller 15 and the charging roller cleaner 18 be determined.
In FIG. 5, abutting rollers 25 that are in contact with the charging roller 15 (having a smaller diameter than the charging roller cleaner 18) are provided at both ends of the charging roller cleaner 18 (FIG. 5 shows only one end). Between the shafts of the charging roller cleaner 18. In this way, the distance between the shafts of the charging roller 15 and the charging roller cleaner 18 can be regulated by the abutting roller (cylindrical member) 25 having a smaller diameter than the charging roller cleaner 18.
Alternatively, the shafts of the charging roller 15 and the charging roller cleaner 18 may be determined by integrating the bearings 21 and 22 of the charging roller 15 and the charging roller cleaner 18. A brush roller can be used as the charging roller cleaner 18, and a resin foam can be used as the material thereof.

3 to 5, the photosensitive drum 10, the charging roller driving gear (photosensitive drum 10 side) 19, the charging roller driving gear (charging roller 15 side) 20, the charging roller bearing 21, and the charging roller cleaner bearing 22 are further illustrated. It is shown.
By using the method for driving the charging roller cleaner 18 of the present invention for a process cartridge that is an image station, the process cartridge can be reduced in size.

1 is a schematic configuration diagram illustrating an embodiment of a color image forming apparatus to which the present invention is applied. It is sectional drawing which shows the process cartridge which is an image station of FIG. It is a schematic front view which shows the structure of the charging roller and charging roller cleaner using embodiment of this invention. FIG. 4 is an enlarged perspective view showing one end of the charging roller cleaner in FIG. 3. It is an expansion perspective view which shows the structure of other embodiment of the charging roller cleaner using embodiment of this invention. It is a schematic front view which shows the conventional charging roller cleaner. FIG. 7 is an enlarged perspective view showing one end of the conventional charging roller cleaner of FIG. 6.

Explanation of symbols

A Image forming device (color image forming device)
DESCRIPTION OF SYMBOLS 1 Intermediate transfer belt 4 Fixing unit 5 Secondary transfer roller 6 Registration roller 8 Transfer paper 10 Image carrier (photoconductor)
11 Process Cartridge 12 Intermediate Transfer Belt Cleaning Unit 13 Transfer Roller 14 Photoconductor Cleaning Unit (Cleaning Blade)
15 Charging means (charging roller)
16 Developing Device 18 Charging Roller Cleaner 19 Charging Roller Drive Gear 20 Charging Roller Drive Gear 21 Bearing (Charging Roller)
22 Bearing (Charging roller cleaner)
23 Gap regulating member (gap roller)
23a Charging roller cleaner drive gear (charging roller side)
24 Charging roller cleaner drive gear (Charging roller cleaner side)
25 Cylindrical member (abutment roller)

Claims (10)

  In an image forming apparatus for transferring a toner image obtained by developing a latent image on an image carrier onto transfer paper and fixing the transferred image on the transfer paper, the surface of a charging roller for charging the surface of the image carrier A charging roller cleaner for removing dirt; the charging roller cleaner is gear-driven by the charging roller; and a gear for driving the charging roller cleaner provided on the charging roller is provided between the image carrier and the charging roller. An image forming apparatus comprising a gap regulating member for providing a gap.   The image forming apparatus according to claim 1, wherein the gap regulating member integrated with the charging roller cleaner driving gear is provided on both axial sides of the charging roller.   The image forming apparatus according to claim 1, wherein shaft diameters of bearing sliding portions of the charging roller cleaner are different on both sides.   4. The image forming apparatus according to claim 1, wherein cylindrical members having a diameter smaller than that of the charging roller cleaner are provided at both ends in the axial direction of the charging roller cleaner. 5.   The image forming apparatus according to claim 4, wherein the cylindrical members provided at both axial ends of the charging roller cleaner are made of resin.   6. The image forming apparatus according to claim 1, wherein bearings of the charging roller and the charging roller cleaner are integrated.   The image forming apparatus according to claim 1, wherein the charging roller cleaner is a brush roller.   The image forming apparatus according to claim 1, wherein a material of the charging roller cleaner is a foaming resin.   9. The charging according to claim 1, wherein the process cartridge supports at least one unit selected from an image carrier, a charging unit, a developing unit, and a cleaning unit and is detachable from the main body of the image forming apparatus. A process cartridge comprising a roller and a charging roller cleaner.   An image forming apparatus comprising the process cartridge according to claim 9.

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