JP2023004131A - Photoreceptor drum, method for manufacturing photoreceptor drum, process unit, and image forming apparatus - Google Patents

Abstract

To provide a photoreceptor drum that can reduce deviation of a surface of a drum with respect to a rotation axis of a shaft, a process unit, and an image forming apparatus.SOLUTION: A photoreceptor drum 100 is obtained by press-fitting a drum flange 120 into an end of a drum element tube 110 and inserting a shaft 130 into the drum flange 120. The photoreceptor drum 100 includes a drive transmission plate 140 that can rotate integrally with the shaft 130, and the drive transmission plate 140 is brought into pressure contact with the drum flange 120 in an axial direction of the shaft 130 to transmit rotational driving force to the drum flange 120.SELECTED DRAWING: Figure 8

Description

The present invention relates to a photoreceptor drum, a method of manufacturing a photoreceptor drum, and a process unit and an image forming apparatus having the photoreceptor drum.

An electrophotographic image forming apparatus has a photosensitive drum in an image forming section. FIG. 9 shows a schematic configuration of a conventional photoreceptor drum 500, and is an exploded view at one end. As shown in FIG. 9, the photoreceptor drum 500 includes a drum tube 510, a drum flange 520 and a shaft 530. As shown in FIG. That is, the drum flanges 520 are press-fitted into both ends of the drum tube 510 , and the shaft 530 is inserted into the shaft hole 523 of the drum flange 520 . The drum flange 520 has a flange portion 521 and a press-fitting portion 522 coaxially formed, and the press-fitting portion 522 is press-fitted to the inner peripheral side of the drum tube 510 . In the process unit having the photosensitive drum 500, a coupling gear 531 is fixed to one end of the shaft 530 for receiving rotational drive from the main body of the image forming apparatus.

In such a photoreceptor drum, a pin or a D-cut is used to prevent rotation of the drum flange relative to the shaft (for example, Patent Document 1). In the illustrated photosensitive drum 500 , a pin 540 is used to prevent rotation of the drum flange 520 with respect to the shaft 530 . 10 is a side view showing the outer (flange portion 521 side) end face of the drum flange 520, and FIG. 11 is a side view of the photosensitive drum 500 (the coupling gear 531 is omitted).

The pins 540 are passed through the shaft 530 so that their axes are perpendicular to each other (see FIG. 9). A groove 524 for inserting a pin 540 is formed in the outer end surface of the drum flange 520 (see FIGS. 9 and 10). That is, in the assembled photosensitive drum 500 , by inserting the pin 540 into the groove 524 , the rotation of the shaft 530 is transmitted to the drum flange 520 via the pin 540 (the drum flange 520 is fixed to the shaft 530 to prevent rotation). is done). At this time, if the pin 540 has a play with respect to the groove 524, the rotation of the photosensitive drum 500 is rattling. be.

JP 2005-24704 A

When the pin 540 is used to prevent rotation of the drum flange 520 to the shaft 530 and the pin 540 fixed to the shaft 530 is press-fitted into the groove 524 of the drum flange 520 as in the conventional example described above, the metal pin 540 is press-fitted into the groove 524 made of resin, and due to the accuracy of the balance of the direction of force and the accuracy of the coaxiality between the pin 540 and the groove 524, a slight deviation occurs between the central axis of rotation of the drum 500 and the central axis of the shaft 530. There is a problem that it affects the fluctuation (radial deflection) of the photoreceptor drum 500, and the fluctuation of the photoreceptor drum 500 tends to increase. That is, the coaxiality of the pin 540 with respect to the outer diameter of the shaft 530 is difficult to obtain accuracy, and as shown in FIG. Similarly, the coaxiality of the groove 524 with respect to the outer diameter of the drum flange 520 is also difficult to obtain accuracy, and as shown in FIG.

As described above, when the position of the pin 540 on the shaft 530 and the position of the groove 524 on the drum flange 520 are shifted, the deflection of the photosensitive drum 500 is affected. Fluctuation of the photoreceptor drum 500 causes misregistration and uneven print density. A similar problem also occurs when the rotation-preventing fixing of the drum flange to the shaft is performed by a D-cut.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photoreceptor drum, a method for manufacturing the photoreceptor drum, a process unit, and an image forming apparatus that can reduce the deflection of the drum surface with respect to the rotation axis of the shaft. With the goal.

In order to solve the above-described problems, a first aspect of the present invention provides a photoreceptor drum that is rotatably supported for use in an image forming apparatus and has a cylindrical shape having an electrophotographic photoreceptor on its surface. a drum tube; flanges press-fitted and fixed to both ends of the drum tube in the axial direction; a drive transmission portion provided further outside the flange in the axial direction of the drum tube; a cylindrical drive shaft that is the center of rotation of the drive transmission section and that passes through the center of rotation of the drum tube, the drive shaft is fixed to the drive transmission section by a predetermined fixing method, and the drive transmission section is It is fixed to the flange.

According to the above configuration, the rotation of the drive shaft is transmitted to the drum flange via the drive transmission portion, and the drive force transmission from the drive transmission portion to the drum flange is achieved by fixing the drive transmission portion to the drum flange. done by Therefore, even if the drive transmission part is wobbled by fixing the drive transmission part to the drive shaft to prevent rotation, the wobble can be prevented from being transmitted to the drum flange. It is possible to reduce the fluctuation of the drum surface (surface of the drum blank) with respect to the shaft).

Further, in the photoreceptor drum, the drive transmission portion is inserted through a screw insertion hole formed in the drive transmission portion, and is fastened to the drum flange in the axial direction of the drive shaft by a screw that is fastened to the drum flange. and the diameter of the screw insertion hole can be made larger than the screw diameter of the screw.

According to the above configuration, the screw passes through the screw insertion hole of the drive transmission part, but since the diameter of the screw insertion hole is larger than the screw diameter of the screw, the screw touches the inner peripheral surface of the screw insertion hole. can be avoided. Therefore, the force acting on the drum flange from the drive transmission portion is only the pressure contact force along the axial direction of the drive shaft, and it is possible to avoid the vibration of the drive transmission portion from being transmitted to the drum flange via the screw.

Further, in the photoreceptor drum, the drive transmission section may be formed as a resin member separate from the drive shaft, and fixed to the drive shaft so as to prevent rotation.

Further, in the above-described photoreceptor drum, the predetermined fixing method is such that a fixing pin provided in a direction perpendicular to the axial direction of the drive shaft is fitted into a groove provided in the drive transmission section. can be done.

In order to solve the above problems, a method for manufacturing a photoreceptor drum according to a second aspect of the present invention is the method for manufacturing a photoreceptor drum described above, wherein the drive shaft is connected to the drive transmission section. After fixing, the drive transmission part is fixed to the flange.

Further, in order to solve the above problems, a process unit according to a third aspect of the present invention is detachable from an image forming apparatus and has at least some functions necessary for electrophotographic image formation. A process unit arranged along the rotation direction of a photosensitive drum, wherein the photosensitive drum is the photosensitive drum described above.

Further, in order to solve the above problems, an image forming apparatus according to a fourth aspect of the present invention is characterized by comprising the process unit described above.

In the photoreceptor drum, the method for manufacturing the photoreceptor drum, the process unit, and the image forming apparatus of the present invention, the rotation of the drive shaft is transmitted to the drum flange via the drive transmission section, and the drive transmission section is shaken. Also, since the vibration can be prevented from being transmitted to the drum flange, it is possible to reduce the vibration of the surface of the photosensitive drum with respect to the rotation axis of the shaft.

1, showing an embodiment of the present invention, is a schematic cross-sectional view of an image forming apparatus. 4 is a perspective view showing a process unit; FIG. 2 is an exploded view of one end of a photoreceptor drum; FIG. FIG. 4 is a side view of a drum flange; 4 is a side view of the drive transmission plate; FIG. 3 is a side view of a photoreceptor drum; FIG. FIG. 7 is a cross-sectional view taken along the line AA of FIG. 6; FIG. 7 is a cross-sectional view taken along the line BB of FIG. 6; 1 is an exploded view of one end of a conventional photosensitive drum; FIG. FIG. 10 is a side view of a drum flange in a conventional photoreceptor drum; FIG. 10 is a side view of a conventional photoreceptor drum; FIG. 10 is an explanatory diagram showing a state in which the pin is misaligned with respect to the outer diameter of the shaft; It is an explanatory view showing a state in which the position of the groove is shifted with respect to the outer diameter of the drum flange.

[Embodiment 1]
BEST MODE FOR CARRYING OUT THE INVENTION 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 example of an image forming apparatus 10 to which the present invention is applied. Although the image forming apparatus 10 shown in FIG. 1 is a color image forming apparatus having a plurality of process units, the present invention is not limited to this, and may be a monochrome image forming apparatus having a single process unit. can also be applied.

The image forming apparatus 10 includes a main body 11, a document reading section 12, a document conveying device 13 and a paper feeding device 14, as shown in FIG. The body portion 11 has an image forming portion for printing an image on recording paper. The document reading section 12 is arranged above the main body section 11 and reads a document when copying the document. The document conveying device 13 sequentially conveys the documents placed on the document set tray toward the document placing table of the document reading section 12 in the automatic reading mode. The paper feed device 14 stocks recording paper and feeds the recording paper to the main body 11 during image formation.

The image data handled by the image forming apparatus 10 corresponds to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y), or a single color (for example, black). It corresponds to the monochrome image that was used. Therefore, the image forming apparatus 10 has four process units 20 associated with black, cyan, magenta, and yellow. Each process unit 20 forms a toner image according to image data using electrophotographic technology.

Each toner image formed by each process unit 20 is sequentially transferred to the intermediate transfer belt 21 and superimposed. Thereby, a color toner image is formed on the intermediate transfer belt 21 . The color toner image on the intermediate transfer belt 21 is transferred onto the recording paper, and the fixing device 22 heats and presses the recording paper to fix the color toner image on the recording paper.

The process unit 20 is configured as a detachable unit with respect to the image forming apparatus 10, as shown in FIG. Further, since the process unit 20 forms an image by a known electrophotographic method, a detailed description thereof will be omitted. Functional units such as a charging unit, a cleaning unit, and a neutralization unit (at least some of the functional units required for electrophotographic image formation) are arranged along the rotation direction of the photosensitive drum 100 .

Next, a specific structure of the photoreceptor drum 100 will be described. FIG. 3 is an exploded view of one end of the photoreceptor drum 100 according to the first embodiment. FIG. 4 is a side view of a drum flange (flange) 120 used in the photoreceptor drum 100. FIG. FIG. 5 is a side view of the drive transmission plate 140 used in the photoreceptor drum 100. FIG. However, the side surface of the photoreceptor drum 100 is simply a term for convenience, and the direction of the side surface of the photoreceptor drum 100 does not necessarily match the side surface of the image forming apparatus 10 in which it is provided.

The photoreceptor drum 100 generally includes a drum tube 110 , a drum flange 120 , a shaft (drive shaft) 130 , and a drive transmission plate (drive transmission section) 140 . The drum tube 110 is a cylindrical member having an electrophotographic photosensitive member on its surface, an aluminum tube on the innermost peripheral side, and a photosensitive layer formed around it. The drum flanges 120 are members made of resin that are press-fitted and fixed to both ends of the drum tube 110 in the axial direction.

The external shape of the drum flange 120 is such that a flange portion 121 and a press-fitting portion 122 are formed coaxially. The flange portion 121 is formed in a substantially disk shape somewhat larger than the outer circumference of the drum tube 110, and is arranged to face the end surface of the drum tube 110 when the drum flange 120 is press-fitted into the drum tube 110. be done. The drum flange 120 is fixed to the drum tube 110 by press-fitting the press-fitting portion 122 into the inner peripheral side of the drum tube 110 . A shaft hole 123 is formed in the center of the drum flange 120 and a shaft 130 is inserted into the shaft hole 123 . The shaft 130 serves as the center of rotation of the drum flange 120 and the drive transmission plate 140 and is arranged so as to pass through the center of rotation of the drum tube 110 . A coupling gear 131 is fixed to one end of the shaft 130 for receiving rotational drive from the main body of the image forming apparatus 10 .

The drive transmission plate 140 is a substantially disc-shaped member arranged outside (flange portion 121 side) with respect to the drum flange 120 in the axial direction of the drum tube 110, and has a shaft hole 141 formed in the center. , the shaft 130 is inserted into the shaft hole 141 .

In the photoreceptor drum 100 according to the first embodiment, rotation-stop fixing of the drum flange 120 to the shaft 130 is performed via the drive transmission plate 140 . That is, the rotational driving force of the shaft 130 is not directly transmitted from the shaft 130 to the drum flange 120, but is transmitted through the drive transmission plate 140 fixed to the shaft 130 by a predetermined fixing method. Here, FIG. 6 is a side view showing the outer end surface of the photosensitive drum 100 (the coupling gear 131 is omitted). 7 is a sectional view taken along line AA of FIG. 6, and FIG. 8 is a sectional view taken along line BB of FIG.

First, driving force transmission from the shaft 130 to the drive transmission plate 140 is performed by a driving force transmission pin (fixed pin) 150 . Specifically, a pin 150 is inserted into the shaft 130 , and a groove (groove portion) 142 (see FIG. 5 ) for fitting the pin 150 is formed in the drive transmission plate 140 . The pins 150 are passed through the shaft 130 so that their axes are perpendicular to each other. In the photosensitive drum 100, by fitting the pins 150 into the grooves 142, the rotation of the shaft 130 is transmitted through the pins 150 to the drive transmission plate. 140 (see FIGS. 6 and 7). Also, the pin 150 is press-fitted into the groove 142 and fixed without play.

Next, the driving force is transmitted from the drive transmission plate 140 to the drum flange 120 by fixing the drive transmission plate 140 to the drum flange 120, more specifically by pressing the drive transmission plate 140 against the drum flange 120. done. As a method for pressing the drive transmission plate 140 against the drum flange 120, the use of screws 160 is preferable. Specifically, screw holes 124 (see FIGS. 3 and 4) for fastening screws 160 are provided at a plurality of locations (at least two locations) in the drum flange 120 , and the screw holes 124 are opposed to the drive transmission plate 140 . Screw insertion holes 143 (see FIGS. 3 and 5) are provided at a plurality of locations so that the screw insertion holes 143 are provided. The plurality of screw holes 124 (or the plurality of screw insertion holes 143) are preferably arranged at equal angular intervals along the circumferential direction. Moreover, the diameter of the screw insertion hole 143 is made larger than the screw diameter of the screw 160 .

The screws 160 pass through the screw insertion holes 143 of the drive transmission plate 140 and are fastened to the screw holes 124 of the drum flange 120 (see FIGS. 6 and 8). At this time, the screw head of the screw 160 has a diameter larger than that of the screw insertion hole 143 , and the screw head of the screw 160 thus fastened pushes the drive transmission plate 140 along the axial direction of the shaft 130 . , the drive transmission plate 140 can be pressed against the drum flange 120 . As a result, a sufficient frictional force is generated between the drive transmission plate 140 and the drum flange 120 in contact with the drive transmission plate 140, so that the drive transmission plate 140 and the drum flange 120 can transmit the driving force without slippage. can be done. A washer may be arranged between the screw head of the screw 160 and the drive transmission plate 140 .

The drive transmission plate 140 is fixed to the shaft 130 to prevent rotation by fitting the pin 150 into the groove 142. The accuracy of coaxiality between the pin 150 and the groove 142 affects the run-out of the drive transmission plate 140. In the plate 140, a relatively large deflection may occur. However, in the configuration of the photosensitive drum 100 , the vibration of the drive transmission plate 140 does not affect the vibration of the drum tube 110 . That is, in the photoreceptor drum 100, it is possible to reduce the deflection of the drum surface with respect to the rotation axis of the shaft. This action will be explained as follows.

As described above, driving force is transmitted from the drive transmission plate 140 to the drum flange 120 by pressing the drive transmission plate 140 against the drum flange 120 by fastening the screws 160 . At this time, the screw 160 passes through the screw insertion hole 143 of the drive transmission plate 140. Since the diameter of the screw insertion hole 143 is larger than the screw diameter of the screw 160, the screw 160 is inserted into the screw insertion hole 143. It is possible to avoid touching the peripheral surface (see FIG. 8). Therefore, the force acting on the drum flange 120 from the drive transmission plate 140 is only the pressing force along the axial direction of the shaft 130 , and the vibration of the drive transmission plate 140 is not transmitted to the drum flange 120 via the screws 160 .

That is, the accuracy of coaxiality of the pin 150 and the groove 142 may affect the deflection of the drive transmission plate 140 but not the deflection of the drum flange 120 and the drum tube 110 . As a result, high coaxial accuracy on the drum surface of the photoreceptor drum 100 can be ensured by eliminating the influence of the coaxial accuracy of the pin 150 and the groove 142. It becomes possible to reduce surface flutter.

The above-described drive transmission configuration (drive transmission configuration via the drive transmission plate 140) may be provided on one end side of the photoreceptor drum 100. In that case, the drive input side of the shaft 130 (cup It is preferably provided on the side where the ring gear 131 is arranged). Moreover, as a manufacturing procedure of the photosensitive drum 100 , it is preferable to fix the drive transmission plate 140 to the drum flange 120 after fixing the shaft 130 to the drive transmission plate 140 .

[Embodiment 2]
In Embodiment 1 above, a configuration in which rotation-preventing fixing (predetermined fixing method) of the drive transmission plate 140 to the shaft 130 is performed by fitting the pin 150 into the groove 142 has been exemplified. However, the present invention is not limited to this, and the detent fixing of the drive transmission plate 140 to the shaft 130 may be performed by a D-cut. That is, a portion of the shaft 130 may be machined to have a D-shaped cross section, and the shaft hole 141 in the drive transmission plate 140 may be formed to have a similar D-shape.

[Embodiment 3]
In Embodiments 1 and 2 described above, drive transmission plate 140 is a separate member from shaft 130 . Forming the drive transmission plate 140 as a separate member from the shaft 130 allows each member to be molded with a suitable material (for example, the drive transmission plate 140 is made of resin and the shaft 130 is made of metal) and a processing method, which reduces costs. There is an advantage that the photoreceptor drum 100 can be easily assembled and parts can be replaced. However, the present invention is not limited to this, as long as the drive transmission plate 140 can rotate integrally with the shaft 130, the drive transmission plate 140 and the shaft 130 are made of the same material (for example, metal). It may be integrally formed.

Further, in Embodiments 1 and 2 described above, the screw 160 is used to press the drive transmission plate 140 against the drum flange 120 . It is also possible to use a press-fitting pin (having no threaded portion and having a pin head corresponding to the screw head of the screw 160) in place of the screw 160, if it can.

The embodiments disclosed this time are exemplifications in all respects and are not grounds for restrictive interpretation. Therefore, the technical scope of the present invention is not to be interpreted only by the above-described embodiments, but is defined based on the claims. In addition, all changes within the meaning and range of equivalence to the claims are included.

10 Image forming apparatus 20 Process unit 100 Photoreceptor drum 110 Drum tube 120 Drum flange (flange)
121 flange portion 122 press-fit portion 123 shaft hole 124 screw hole 130 shaft (drive shaft)
131 Coupling gear 140 drive transmission plate (drive transmission part)
141 shaft hole 142 groove (groove)
143 screw insertion hole 150 pin (fixing pin)
160 screw

Claims (7)

In a rotatably supported photosensitive drum used in an image forming apparatus,
a cylindrical drum tube having an electrophotographic photosensitive member on its surface;
Flanges press-fitted and fixed to both ends of the drum tube in the axial direction;
a drive transmission portion provided outside the flange in the axial direction of the drum tube;
a cylindrical drive shaft that is the center of rotation of the flange and the drive transmission portion and that passes through the center of rotation of the drum tube;
with
A photosensitive drum, wherein the drive shaft is fixed to the drive transmission section by a predetermined fixing method, and the drive transmission section is fixed to the flange. The photoreceptor drum according to claim 1,
The drive transmission portion is fixed to the drum flange by a screw that passes through a screw insertion hole formed in the drive transmission portion and is fastened to the drum flange in the axial direction of the drive shaft,
A photosensitive drum, wherein the diameter of the screw insertion hole is larger than the screw diameter of the screw. The photoreceptor drum according to claim 1 or 2,
The photoreceptor drum, wherein the drive transmission section is formed as a resin member separate from the drive shaft, and fixed to the drive shaft so as to prevent rotation. The photoreceptor drum according to any one of claims 1 to 3,
The predetermined fixing method is a configuration in which a fixing pin provided in a direction perpendicular to the axial direction of the drive shaft is fitted into a groove provided in the drive transmission section. A method for manufacturing a photoreceptor drum according to any one of claims 1 to 4,
A method of manufacturing a photoreceptor drum, wherein the drive shaft is fixed to the drive transmission part, and then the drive transmission part is fixed to the flange. A process unit which is detachable from an image forming apparatus and in which at least a part of functional units required for electrophotographic image formation are arranged along the rotation direction of a photosensitive drum,
A process unit, wherein the photoreceptor drum is the photoreceptor drum according to any one of claims 1 to 4. An image forming apparatus comprising the process unit according to claim 6 .

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