JP7512680B2 - Process cartridge, method for manufacturing process cartridge, and image forming apparatus - Google Patents

Description

The present invention relates to a process cartridge, a method for manufacturing a process cartridge, and an image forming apparatus.

Conventionally, in image forming devices such as copiers and printers, a process cartridge has been widely used in which a photosensitive drum (hereinafter referred to as "image carrier") and a developing roller (hereinafter referred to as "developer carrier") are housed in a housing, and the image carrier and developer carrier are replaced together with the housing. In such a process cartridge, it is necessary to accurately position the image carrier and developer carrier so that the gap between them (hereinafter referred to as "development gap (PG)") does not fluctuate.

A known method for positioning the image carrier and developer carrier is to provide a holding member that holds the rotation axis (rotation center axis) of each and attach the holding member to a mounting portion formed on a side panel of the housing, for example.

However, there is variation in the dimensional accuracy of the holding member, which is a positioning component, and also in the positional accuracy of the mounting portion formed to mount this holding member. When these variations accumulate, there is a problem in that the mounting position accuracy of the image carrier and developer carrier deteriorates.

In response to this, Patent Document 1 proposes an image forming device that can position each imaging process cartridge with a simple configuration and an easy adjustment mechanism without significantly increasing the number of parts or increasing the weight of parts to improve the strength of the device, and that can ensure a highly accurate narrow PG.The image forming device has a positioning holder integrated into the side plate of the main body, and the positioning holder has a reference axis that positions the photosensitive member and a developing roller bearing that positions the developing roller, and the inner diameter and outer shape of the developing roller bearing are eccentric.

The development gap (PG) is an important characteristic value that determines image quality such as image density and carrier adhesion image, and mechanical quality such as toner scattering, and therefore requires strict tolerance.
In the image forming apparatus of Patent Document 1, positioning and fixing of the housing are performed using a face plate (a plate-shaped part), so it is difficult to avoid the effects of variations in the dimensional accuracy of the parts, and it may be difficult to stabilize the development gap.

The present invention aims to provide a process cartridge that can avoid the effects of component dimensional accuracy and stabilize the development gap formed between the image carrier and the developer carrier.

In order to achieve the above object, the process cartridge of the present invention includes an image carrier , a developer carrier disposed spaced apart from the image carrier, a first housing that houses the image carrier, a second housing that houses the developer carrier, and a fixed plate member that fixes the first housing and the second housing, the fixed plate member having a plurality of openings through which fastening members can be inserted, an image carrier holding portion that rotatably holds the image carrier, and a through hole through which a rotational axis of the developer carrier is inserted, the opening diameter of the through hole being 100 mm to 150 mm from the rotational center of the image carrier. The diameter of the developer carrier rotation central axis is larger than the diameter of the developer carrier rotation central axis in a linear direction connecting the rotation center of the image carrier and the rotation center of the developer carrier, and is approximately the same as the diameter of the developer carrier rotation central axis in a direction perpendicular to the line connecting the rotation center of the image carrier and the rotation center of the developer carrier, and when the fixed plate member is fastened and fixed to the first housing and the second housing by the fastening members, the developer carrier rotation central axis does not abut against the inner wall of the through hole in the linear direction connecting the rotation center of the image carrier and the rotation center of the developer carrier.

The present invention provides a process cartridge that can avoid the effects of component dimensional accuracy and stabilize the development gap formed between the image carrier and the developer carrier.

FIG. 2 is a side view showing a schematic external appearance of a first housing that houses an image carrier and a second housing that houses a developer carrier. FIG. 2 is an external perspective view of a process cartridge according to an embodiment of the present invention. FIG. 11 is an external perspective view of a conventional process cartridge. 1A is an explanatory diagram showing a typical fixing plate member of a process cartridge according to the present invention, and FIG. 1B is an explanatory diagram showing a typical position fixing member of a conventional process cartridge. 11 is an explanatory diagram showing fastening of a fixed plate member using a jig; FIG. 10A to 10C are explanatory diagrams showing examples of arrangements of fastening members on a fixed plate member. 10A to 10C are explanatory diagrams showing examples of arrangements of fastening members on a fixed plate member. 10A to 10C are explanatory diagrams showing examples of arrangements of fastening members on a fixed plate member. 10A to 10C are explanatory diagrams showing examples of arrangements of fastening members on a fixed plate member. FIG. 11 is an explanatory view illustrating a fixed plate member of a process cartridge according to a second embodiment of the present invention. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention.

The process cartridge, the manufacturing method of the process cartridge, and the image forming apparatus according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiment shown below, and can be modified within the scope of what a person skilled in the art can imagine, such as other embodiments, additions, modifications, deletions, etc., and any aspect is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[Process cartridge]
FIG. 1 shows an example of a side view of a housing that constitutes a process cartridge.
The process cartridge is formed by connecting and fixing a first housing (photosensitive unit) 61 that houses an image carrier (photosensitive drum) 20 and a second housing (developing unit) 62 that houses a developer carrier (developing roller) 41. Various process members are housed in each housing.

FIG. 3 is a perspective view showing an example of a conventional process cartridge.
In the conventional process cartridge shown in FIG. 3, a first housing 61 housing the image carrier 20 and a second housing 62 housing the developer carrier 41 are connected and fixed by a position fixing member 68 .
A schematic diagram of the position fixing member 68 attached to the first housing 61 and the second housing 62 is shown in FIG.
The image carrier 20 and the developer carrier rotation central shaft 41a are positioned by an image carrier holding portion 67 and a through hole 66 formed in a position fixing member 68. The position fixing member 68 is formed with an opening 64 through which a fastening member 65 is inserted. The position fixing member 68 is fastened to the first housing 61 and the second housing 62 by using the fastening members 65 (65a to 65c) to form a process cartridge.

In the conventional process cartridge shown in Figure 3, tolerance buildup can be reduced by positioning and fixing using a single part, the position fixing member 68. However, there is a risk that it may be difficult to stabilize the development gap due to component variations in the position fixing member 68 itself.

In contrast, in the process cartridge according to the present invention, the member that fixes the first housing 61 and the second housing 62 has the function of fixing the housings together only, and the image carrier 20 and the developer carrier 41 are positioned using a separate jig or the like, which avoids the effects of the dimensional accuracy of the parts used for fixing, improves the mounting position accuracy of the image carrier 20 and the developer carrier 41, and stabilizes the development gap.

(First embodiment)
FIG. 2 shows a process cartridge according to an embodiment of the present invention.
The process cartridge of this embodiment shown in Figure 2 comprises an image carrier 20, a developer carrier 41 arranged at a distance from the image carrier 20, a first housing 61 that houses the image carrier 20, a second housing 62 that houses the developer carrier 41, and a fixed plate member 63 that fixes the first housing 61 and the second housing 62.

A schematic diagram of the fixed plate member 63 is shown in FIG.
The fixed plate member 63 has a plurality of openings 64 through which fastening members 65 can be inserted, an image carrier holding portion 67 that holds the image carrier 20 so that it can be rotated freely, and a through hole 66 through which the developer carrier rotation center shaft 41a is inserted, and the opening diameter of the through hole 66 is larger than the diameter of the developer carrier rotation center shaft 41a, so that when the fixed plate member 63 is fastened and fixed to the first housing 61 and the second housing 62 by the fastening members 65, the developer carrier rotation center shaft 41a does not abut against the inner wall of the through hole 66.
The image carrier 20 and the developer carrier 41 are fixed with a predetermined distance therebetween.

The image carrier 20 is rotatably held by a first housing 61 and a fixed plate member 63 , and the developer carrier 41 is rotatably held by a second housing 62 .
The distance between the image carrier 20 and the developer carrier 41 is determined by fastening and fixing the fixed plate member 63 to the second housing 62, but the developer carrier 41 is not fixed in position by the fixed plate member 63, but is positioned by a separate jig during the fastening process of the fixed plate member 63.

The process cartridge of this embodiment can be assembled by first fastening the first housing 61 and the fixed plate member 63 with fastening members 65 (65a and 65b), and then fastening the second housing 62 and the fixed plate member 63 with fastening members 65 (65c and 65d) while adjusting the separation distance between the image carrier 20 and the developer carrier 41 to a predetermined distance.
Methods for adjusting the distance between the image carrier 20 and the developer carrier 41 to a predetermined distance include using a means capable of measuring the distance, or using a jig or the like formed to achieve a predetermined distance.

FIG. 5 is an explanatory diagram showing a state in which the fixed plate member 63 is attached using a jig 80 capable of adjusting the distance between the image carrier 20 and the developer carrier 41. As shown in FIG.
As shown in Figure 5, with a jig 80 for adjusting the distance between the image carrier 20 and the developer carrier 41 abutted against the image carrier 20 and the developer carrier rotation central axis 41a, the second housing 62 and the fixed plate member 63 are fastened together through an opening 81 formed in the jig 80.

The image carrier 20 is held by the image carrier holding portion 67 formed on the fixed plate member 63, but the developer carrier rotation center shaft 41a is not fixed and does not abut against the inner wall of the through hole 66 as shown in Figures 2 and 4 (A). Therefore, a stable development gap can be obtained without being affected by the component accuracy of the fixed plate member 63.

The fastening member 65 may be, for example, a screw that is screwed into a threaded hole formed in the first housing and the second housing.
It is preferable that a locking agent is applied to the fastening member 65. There are no particular limitations on the locking agent, and known agents such as adhesives and ultraviolet-curing resins can be used.
For example, a locking agent can be applied to the fastening member 65 in advance, and the fastening member 65 can be inserted into a screw hole of a fastening target. The applied locking agent hardens to prevent rotation of the fastening member 65, and the fixing strength of the fixed plate member 63 to the first housing 61 and the second housing 62 can be improved. The improved fixing strength can realize stabilization of the development gap.

As the fastening member 65, a screw with a washer can be used.
By using a screw with a washer as the fastening member 65, an anti-loosening effect is obtained and the fixing strength can be improved without using other parts or structures, so that it is possible to achieve both stabilization of the development gap and space saving.

Moreover, as the fastening member 65, a serrated screw can be used.
By using a serrated screw as the fastening member 65, an anti-loosening effect is obtained and the fixing strength can be improved without using other parts or structures, thereby achieving both stabilization of the development gap and space saving.

Second Embodiment
FIG. 10 is a schematic diagram of the fixed plate member 63 of the process cartridge according to this embodiment.
As shown in Figure 10, the opening diameter of the through hole 66 of the fixed plate member 63 of the process cartridge of this embodiment is larger than the diameter of the developer carrier rotation center shaft 41a in the linear direction connecting the rotation center of the image carrier 20 and the rotation center of the developer carrier 41, and is approximately the same as the diameter of the developer carrier rotation center shaft 41a in the direction perpendicular to the line connecting the rotation center of the image carrier 20 and the rotation center of the developer carrier 41.

10A, when the fixed plate member 63 is fastened to the first housing 61 and the second housing 62 by the fastening members 65, the developer carrier rotation central shaft 41a does not abut against the inner wall of the through hole 66 in the linear direction connecting the rotation center of the image carrier 20 and the rotation center of the developer carrier 41. The image carrier 20 and the developer carrier 41 are fixed with a predetermined distance between them.
According to this embodiment, even though the developer carrier 41 is assembled while adjusting the development gap direction, the position of the developer carrier 41 in the rotational direction relative to the image carrier 20 is determined by the fixed plate member 63. Furthermore, since adjustment is required in only one direction during assembly, the configuration of the device used for assembling the process cartridge can be simplified.

Furthermore, as shown in FIG. 10 (B), before and after the fixed plate member 63 is abutted against the first housing 61 and the second housing 62 and fastened and fixed, when the developer carrier rotation center shaft 41a inserted through the through hole 66 is moved to a position closest to the image carrier 20, the image carrier 20 and the developer carrier 41 do not abut against each other.
It is preferable to design the position of the inner wall of the through hole so that when the developer carrier central axis 41a is moved closest to the image carrier 20, a gap smaller than the development gap is formed between the image carrier 20 and the developer carrier 41.
This makes it possible to fix the development gap while preventing damage caused by contact between the image carrier 20 and the developer carrier 41 even during the operation of fastening and fixing the fixed plate member 63 .

By appropriately setting the fastening positions of the fastening members 65 on the fixing plate member 63, the fixing strength and fixing accuracy to the first housing 61 and the second housing 62 can be improved.
It is preferable that the number of fastening points by the fastening members 65 that fasten the fixing plate member 63 to the first housing 61 and the second housing 62 is three or more.
An example of the arrangement of the fastening members 65 on the fixed plate member 63 of the process cartridge of this embodiment will be described below.

(First arrangement example)
The present embodiment will be described with reference to FIG.
6A is a schematic diagram showing a state in which the fixed plate member 63 is fastened to the first housing 61 and the second housing 62. In the figure, L1 is a line connecting the rotation center of the image carrier 20 and the rotation center of the developer carrier 41, L2 is a line passing through the rotation center of the image carrier 20 and perpendicular to L1, and L3 is a line passing through the center of the developer carrier rotation central axis 41a and perpendicular to L1.
FIG. 6B is a perspective view of the process cartridge of this embodiment.
The process cartridge of this embodiment has four fastening points using fastening members 65, and at least one of the fastening positions using the fastening members 65 (65c, 65d) that fasten the fixed plate member 63 to the second housing 62 is located closer to the end on the second housing side than the center of the inserted developer carrier rotation center shaft 41a, in the direction along the straight line connecting the rotation center of the image carrier 20 and the rotation center of the developer carrier 41.

As shown in Figure 6 (A), the fastening position of the fastening member 65d is at the end on the second housing side indicated by the arrow in the direction along L1 rather than the straight line passing through the center of the developer carrier rotation axis 41a indicated by L3.
By arranging in this manner, the fixing accuracy by the fixed plate member 63 can be improved, the mounting position accuracy of the image carrier 20 and the developer carrier 41 can be increased, and the development gap can be stabilized.

(Second arrangement example)
The present embodiment will be described with reference to FIG.
7A is a schematic diagram showing a state in which the fixed plate member 63 is fastened to the first housing 61 and the second housing 62. In the figure, L1 is a line connecting the rotation center of the image carrier 20 and the rotation center of the developer carrier 41, L2 is a line passing through the rotation center of the image carrier 20 and perpendicular to L1, and L3 is a line passing through the center of the developer carrier rotation central axis 41a and perpendicular to L1.
FIG. 7B is a perspective view of the process cartridge of this embodiment.
The process cartridge of this embodiment has four fastening points using fastening members 65, and at least one of the fastening positions using the fastening members 65 (65a, 65b) that fasten the fixed plate member 63 to the first housing 61 is located closer to the end on the first housing side than the center of rotation of the image carrier 20 in the direction along the straight line connecting the center of rotation of the image carrier 20 and the center of rotation of the developer carrier 41.

As shown in FIG. 7A, the fastening position of the fastening member 65a is at the end on the first housing side indicated by the arrow in the direction along L1 rather than the straight line passing through the center of rotation of the image carrier 20 indicated by L2.
By arranging in this manner, the fixing accuracy by the fixed plate member 63 can be improved, the mounting position accuracy of the image carrier 20 and the developer carrier 41 can be increased, and the development gap can be stabilized.

(Third arrangement example)
The present embodiment will be described with reference to FIG.
8A is a schematic diagram showing a state in which the fixed plate member 63 is fastened to the first housing 61 and the second housing 62. In the figure, L1 is a line connecting the rotation center of the image carrier 20 and the rotation center of the developer carrier 41, L2 is a line passing through the rotation center of the image carrier 20 and perpendicular to L1, and L3 is a line passing through the center of the developer carrier rotation central axis 41a and perpendicular to L1.
FIG. 8B is a perspective view of the process cartridge of this embodiment.
The process cartridge of this embodiment has five fastening points using fastening members 65, and one or more fastening positions using the fastening members 65 (65c, 65d, 65e) that fasten the fixed plate member 63 to the second housing 62 are provided in each of two areas divided by a straight line L1 connecting the center of rotation of the image carrier and the center of rotation of the developer carrier.

As shown in FIG. 8A, the fastening positions of fastening members 65c and 65d are provided in one area divided by a straight line L1, and the fastening position of fastening member 65e is provided in the other area divided by the straight line L1.
By arranging in this manner, the fixing accuracy by the fixed plate member 63 can be improved, the mounting position accuracy of the image carrier 20 and the developer carrier 41 can be increased, and the development gap can be stabilized.

(Fourth arrangement example)
The present embodiment will be described with reference to FIG.
9A is a schematic diagram showing a state in which the fixed plate member 63 is fastened to the first housing 61 and the second housing 62. In the figure, L1 is a line connecting the rotation center of the image carrier 20 and the rotation center of the developer carrier 41, L2 is a line passing through the rotation center of the image carrier 20 and perpendicular to L1, and L3 is a line passing through the center of the developer carrier rotation central axis 41a and perpendicular to L1.
FIG. 8B is a perspective view of the process cartridge of this embodiment.
The process cartridge of this embodiment has five fastening points using fastening members 65, and the fastening positions using the fastening members 65 (65a, 65b) that fasten the fixed plate member 63 to the first housing 61 are provided in two areas divided by a straight line L1 connecting the center of rotation of the image carrier and the center of rotation of the developer carrier, at least one of which is provided in each area.

As shown in FIG. 9A, the fastening position of fastening member 65a is provided in one area divided by straight line L1, and the fastening position of fastening member 65b is provided in the other area divided by straight line L1.
By arranging in this manner, the fixing accuracy by the fixed plate member 63 can be improved, the mounting position accuracy of the image carrier 20 and the developer carrier 41 can be increased, and the development gap can be stabilized.

As described above, the process cartridge according to the present invention can avoid the effects of component dimensional accuracy and stabilize the development gap formed between the image carrier and the developer carrier, so that by applying the process cartridge to an image forming device, it is possible to output high-quality images.

[Manufacturing method of process cartridge]
The manufacturing method of the process cartridge according to the present invention includes an image carrier 20, a developer carrier 41 arranged at a distance from the image carrier 20, a first housing 61 that houses the image carrier 20, a second housing 62 that houses the developer carrier 41, and a fixed plate member 63 that fixes the first housing 61 and the second housing 62, wherein the fixed plate member 63 has a plurality of openings 64 through which fastening members 65 can be inserted, an image carrier holding portion 67 that holds the image carrier 20 so that it can be rotatably moved, and a through hole 66 through which the developer carrier rotation central shaft 41a is inserted, and after a step of fastening the first housing 61 and the fixed plate member 63 with the fastening members 65, a step of fastening the second housing 62 and the fixed plate member 63 with the fastening members 65 is performed while adjusting the distance between the image carrier 20 and the developer carrier 41 to a predetermined distance.
Methods for adjusting the distance between the image carrier 20 and the developer carrier 41 to a predetermined distance include using a means capable of measuring the distance, or using a jig or the like formed to achieve a predetermined distance.

In addition, the manufacturing method of the process cartridge according to the present invention includes a process cartridge including an image carrier 20, a developer carrier 41 disposed at a distance from the image carrier 20, a first housing 61 that houses the image carrier 20, a second housing 62 that houses the developer carrier 41, and a fixed plate member 63 that fixes the first housing 61 and the second housing 62, the fixed plate member 63 having a plurality of openings 64 through which fastening members 65 can be inserted, an image carrier holding portion 67 that holds the image carrier 20 so as to be freely rotatable, and a developer carrier 41 that is fixed to the first housing 61 and the second housing 62. In the manufacturing method of a process cartridge having a through hole 66 through which the carrier rotation central shaft 41a passes, after the step of fastening the first housing 61 and the fixed plate member 63 with a fastening member 65, a step of fastening the second housing 62 and the fixed plate member 63 through an opening 81 formed in the jig 80, which adjusts the distance between the image carrier 20 and the developer carrier 41, is performed in a state in which the jig 80 is in contact with the image carrier 20 and the developer carrier rotation central shaft 41a.

That is, the manufacturing method of the process cartridge according to the present invention involves a process of fastening and fixing the fixed plate member 63 to the first housing 61 without positioning and fixing the developer carrier rotation shaft 41a, and then fastening and fixing it to the second housing 62 with the developer carrier rotation shaft 41a positioned using a jig such as that shown in Figure 5.
By using this method, it is possible to manufacture a process cartridge in which the accuracy of the development gap is ensured, without being affected by the component accuracy of the fixed plate member 63 .

[Image forming apparatus]
The image forming apparatus according to the present invention includes the above-mentioned process cartridge according to the present invention.
An example of an image forming apparatus includes an image carrier 20 on whose surface an electrostatic latent image is formed, a charging means for charging the surface of the image carrier 20 which is rotated, an information writing means for forming an electrostatic latent image on the surface of the image carrier 20 after charging, a developing means for developing the electrostatic latent image as a toner image by a developer carried on a developer carrier 41, a supplying means for supplying toner to the developing section, a container containing toner, a transfer means for forming an electric field between the image carrier 20 and the toner image on the image carrier 20 and transferring the toner image on the image carrier 20 to a transfer material, a fixing means for fixing the toner image to the recording medium, a paper feeding means for feeding the recording medium, a conveying means for conveying the recording medium, a positioning means for aligning the position of the recording medium, a paper ejection means for ejecting the recording medium after the toner image has been fixed to the recording medium, a double-sided conveying means for conveying the recording medium to latently image and fix the toner images on both sides of the recording medium, and a conveying means for conveying from a manual feed tray.

FIG. 10 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention.
The image forming apparatus 100 shown in FIG. 10 is a tandem type color printer in which image forming units for forming a plurality of color images are arranged side by side along the extension direction of the belt.
It should be noted that the present invention is not limited to this system, and can be applied to copying machines, facsimile machines, and the like in addition to printers.

The image forming device 100 employs a tandem structure in which image carriers (photoconductor drums) 20Y, 20C, 20M, and 20Bk are arranged in parallel to form images corresponding to the colors separated into yellow, cyan, magenta, and black.

In the image forming apparatus 100, the visible images formed on the image carriers 20Y, 20C, 20M, and 20Bk are primarily transferred to an intermediate transfer body (hereafter referred to as a transfer belt) 11, which is an endless belt that can move in the direction of arrow A1 while facing each image carrier. By executing this primary transfer process, the images of each color are superimposed and transferred, and then, by executing a secondary transfer process to a recording medium (e.g., a recording sheet, etc.) S, they are transferred all at once.

Around each image carrier 20, a device for performing image forming processing in accordance with the rotation of the image carrier 20 is arranged.
Taking the image carrier 20Bk which forms a black image as a representative, the charging device 30Bk which performs the image forming process along the rotation direction of the image carrier 20Bk, the developing device 40Bk equipped with the developer carrier 41Bk, the primary transfer roller 12Bk, and the cleaning device 50Bk are arranged. An optical writing device 8 is used for writing using the writing light Lb which is performed after charging.

In the overlapping transfer onto the transfer belt 11, the visible images formed on the image carriers 20Y, 20C, 20M, and 20Bk are transferred and overlapped at the same position on the transfer belt 11 as the transfer belt 11 moves in the A1 direction. For this reason, the transfer is performed with shifted timing from the upstream side to the downstream side in the A1 direction by applying a voltage to the primary transfer rollers 12Y, 12C, 12M, and 12Bk arranged opposite the image carriers 20Y, 20C, 20M, and 20Bk across the transfer belt 11.

The image carriers 20Y, 20C, 20M, and 20Bk are lined up in this order from the upstream side in the A1 direction. The image carriers 20Y, 20C, 20M, and 20Bk are provided in image stations for forming yellow, cyan, magenta, and black images, respectively.

The image forming device 100 has four image stations that perform image formation processing for each color, a transfer belt unit 10 that is arranged above and facing each of the image carriers 20Y, 20C, 20M, and 20Bk and includes a transfer belt 11 and primary transfer rollers 12Y, 12C, 12M, and 12Bk, a secondary transfer roller 5 that is arranged opposite the transfer belt 11 and rotates in conjunction with the transfer belt 11, a belt cleaning device 13 that is arranged opposite the transfer belt 11 and cleans the transfer belt 11, and an optical writing device 8 that is arranged below and facing these four image stations.

The optical writing device 8 is equipped with a semiconductor laser as a light source, a coupling lens, an fθ lens, a toroidal lens, a folding mirror, and a rotating polygon mirror as a deflection means. The optical writing device 8 is configured to emit writing light Lb corresponding to each color to each image carrier 20Y, 20C, 20M, and 20Bk to form an electrostatic latent image on the image carriers 20Y, 20C, 20M, and 20Bk. For convenience, the writing light Lb is labeled only for the image station for black images in FIG. 10, but the same applies to the other image stations.

The image forming apparatus 100 is provided with a sheet feeding device 91 as a paper feed cassette that holds recording media S to be transported between the image carriers 20Y, 20C, 20M, and 20Bk and the transfer belt 11. In addition, a pair of registration rollers 4 is provided that feeds the recording media S transported from the sheet feeding device 91 toward the transfer section between each image carrier and the transfer belt 11 at a predetermined timing that matches the timing of the formation of a toner image by the image station. In addition, a sensor is provided that detects when the leading edge of the recording media S reaches the pair of registration rollers 4.

The image forming apparatus 100 is also provided with a fixing device 200 as a roller fixing type fixing unit for fixing the toner image onto the recording medium S to which the toner image has been transferred, and a discharge roller 7 for discharging the fixed recording medium S to the outside of the main body of the image forming apparatus 100. The upper part of the main body of the image forming apparatus 100 is also provided with a paper discharge tray 17 for stacking the recording medium S discharged to the outside of the main body of the image forming apparatus 100 by the discharge roller 7. The lower side of the paper discharge tray 17 is also provided with toner bottles 9Y, 9C, 9M, and 9Bk filled with toner of each color, yellow, cyan, magenta, and black.

The transfer belt unit 10 includes the transfer belt 11, primary transfer rollers 12Y, 12C, 12M, and 12Bk, as well as a drive roller 72 and a driven roller 73 around which the transfer belt 11 is wound.

The driven roller 73 also functions as a tension applying means for the transfer belt 11, and for this reason, the driven roller 73 is provided with a biasing means using a spring or the like. The transfer belt unit 10, the primary transfer rollers 12Y, 12C, 12M, 12Bk, the secondary transfer roller 5, and the cleaning device 13 constitute the transfer device 71.

The sheet feeding device 91 is disposed at the bottom of the main body of the image forming device 100, and has a feeding roller 3 that contacts the upper surface of the uppermost recording medium S. The feeding roller 3 is rotated counterclockwise in the figure to feed the uppermost recording medium S toward the pair of registration rollers 4.

The cleaning device 13 provided in the transfer device 71, although not shown in detail, has a cleaning brush and a cleaning blade disposed to face and abut against the transfer belt 11. The cleaning device 13 cleans the transfer belt 11 by scraping off and removing foreign matter such as residual toner on the transfer belt 11 with the cleaning brush and cleaning blade.
The cleaning device 13 also has a discharge means for carrying away and discarding the residual toner removed from the transfer belt 11 .

20 Image carrier (photosensitive drum)
41 Developer carrier (developing roller)
Reference Signs List 41a Rotating shaft 61 First housing 62 Second housing 63 Fixed plate member 64 Opening 65 Fastening member 66 Through hole 67 Image carrier holding portion 68 Position fixing member 80 Jig

JP 2007-108262 A

Claims (13)

the developer carrier is disposed spaced apart from the image carrier; a first housing that houses the image carrier; a second housing that houses the developer carrier; and a fixed plate member that fixes the first housing and the second housing;
the fixed plate member has a plurality of openings through which fastening members can be inserted, an image carrier holding portion that rotatably holds the image carrier, and a through hole through which a rotational center shaft of the developer carrier is inserted,
an opening diameter of the through hole is larger than a diameter of the developer carrier rotation central shaft in a linear direction connecting the rotation center of the image carrier and the rotation center of the developer carrier, and is substantially the same as a diameter of the developer carrier rotation central shaft in a direction perpendicular to the linear direction connecting the rotation center of the image carrier and the rotation center of the developer carrier;
a developer carrier rotation center axis that does not abut against an inner wall of the through hole in a linear direction connecting the rotation center of the image carrier and the rotation center of the developer carrier when the fixed plate member is fastened to the first housing and the second housing by the fastening member. 2. The process cartridge according to claim 1, wherein when the developer carrier rotation central shaft inserted into the through hole is moved to a position closest to the image carrier, the image carrier and the developer carrier do not come into contact with each other . the image carrier is rotatably held by the first housing and the fixed plate member, and the developer carrier is rotatably held by the second housing,
3. The process cartridge according to claim 1, wherein the distance between said image carrier and said developer carrier is determined by fastening said fixed plate member to said second casing. 3. A process cartridge according to claim 1, wherein the fastening member is coated with a locking agent. 5. A process cartridge according to claim 1, wherein said fastening member is a screw with a washer. 5. A process cartridge according to claim 1, wherein said fastening member is a serrated screw. At least one of the fastening positions of the fastening member for fastening the fixing plate member and the second housing is
7. The process cartridge according to claim 1, wherein in a direction along a straight line connecting the rotation center of the image carrier and the rotation center of the developer carrier, the developer carrier is positioned closer to the end portion on the second casing side than the center of the developer carrier rotation central shaft through which the developer carrier is inserted. A process cartridge as described in any one of claims 1 to 7, characterized in that at least one of the fastening positions of the fastening member that fastens the fixed plate member and the first housing is located at a position closer to the end of the first housing side than the center of rotation of the image carrier in a direction along a straight line connecting the center of rotation of the image carrier and the center of rotation of the developer carrier. 9. The process cartridge according to claim 1, wherein the number of fastening points by the fastening members for fastening the fixed plate member to the first housing and the second housing is three or more. 10. A process cartridge according to claim 1, wherein the fastening positions of the fastening member for fastening the fixed plate member and the first housing are provided in two areas divided by a straight line connecting the rotation center of the image carrier and the rotation center of the developer carrier, and the fastening positions of the fastening member for fastening the fixed plate member and the first housing are provided in two areas divided by a straight line connecting the rotation center of the image carrier and the rotation center of the developer carrier. 10. A process cartridge according to claim 1, wherein the fastening positions of the fastening member for fastening the fixed plate member and the second housing are provided in two areas divided by a straight line connecting the rotation center of the image carrier and the rotation center of the developer carrier, and the fastening positions of the fastening member for fastening the fixed plate member and the second housing are provided in two areas divided by a straight line connecting the rotation center of the image carrier and the rotation center of the developer carrier. A method for manufacturing a process cartridge comprising: an image carrier; a developer carrier disposed spaced apart from the image carrier; a first housing that houses the image carrier; a second housing that houses the developer carrier; and a fixed plate member that fixes the first housing and the second housing, the fixed plate member having a plurality of openings through which fastening members can be inserted, an image carrier holding portion that rotatably holds the image carrier, and a through hole through which a rotational center shaft of the developer carrier is inserted,
After the step of fastening the first housing and the fixing plate member with the fastening member,
A method for manufacturing a process cartridge, comprising the steps of: fastening the second housing and the fixed plate member through an opening formed in a jig that adjusts the distance between the image carrier and the developer carrier, while the jig is abutted against the image carrier and the central axis of rotation of the developer carrier. 12. An image forming apparatus comprising the process cartridge according to claim 1 .