JP5791315B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, a printer, or a complex machine of these.

  A configuration in which a process cartridge provided with a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) in the image forming apparatus main body can be freely attached and detached is generally known. In such a configuration, the configuration of Patent Document 1 is known as a configuration in which after the process cartridge is mounted on the apparatus main body, the driving force on the apparatus main body side is transmitted to the photosensitive drum to rotate the photosensitive drum.

  The configuration of Patent Document 1 will be described with reference to FIGS. 1 and 5 to 7. FIG. 1 is a schematic view when the process cartridge 11 is mounted on an image forming apparatus main body (hereinafter simply referred to as “apparatus main body”) 9. A cartridge door 9a is opened and closed when the process cartridge 11 is attached to and detached from the apparatus main body 9. A coupling shaft 10 transmits the driving force of the apparatus main body 9 to the process cartridge 11.

  The cartridge door 9a provided in the apparatus main body 9 is opened, and the process cartridge 11 is inserted in the mounting direction a in FIG.

  Next, the operation of the coupling shaft 10 when the process cartridge 11 is attached to or detached from the apparatus main body 9 will be described.

  FIG. 5 is a perspective view showing the main parts of the main body gear shaft 3 and the coupling shaft 10. In FIG. 5, reference numeral 3 a denotes a driving force transmission pin that is provided at the tip of the main body gear shaft 3 and transmits the driving force to the process cartridge 11. 10f is a conical body gear bearing surface that is expanded toward the body gear shaft 3 side, and 10g is a driven projection that transmits driving force to the coupling shaft 10 by contacting the driving force transmission pin 3a. It is.

  When the process cartridge 11 is inserted in a mounting direction a in FIG. 5 along a guide (not shown) provided in the apparatus main body 9, the coupling shaft 10 engages with the main body gear shaft 3. The engagement here means a state in which the axis L3 of the main body gear shaft 3 and the axis L2 of the coupling shaft 10 are substantially coaxial as shown in FIG. Say.

  6A to 6C are longitudinal sectional views of the coupling portion between the coupling shaft 10 and the main body gear shaft 3 as viewed from the lower side of the apparatus main body 9. 3 d is the tip of the main body gear shaft 3. A drum shaft 13 transmits the driving force of the coupling shaft 10 to a photosensitive drum (not shown). L 1 is the axis of the drum shaft 13. The coupling shaft 10 is attached to the drum shaft 13 so as to be inclined with respect to the axis L1 of the drum shaft 13.

  The coupling shaft 10 has a first angular position shown in FIG. 6C for transmitting the driving force of the main body gear shaft 3 to the drum shaft 13. Further, the coupling shaft 10 has a second angular position shown in FIG. 6B that can be swung from the first angular position. When the process cartridge 11 is mounted on the apparatus main body 9, the coupling shaft 10 swings from the second angular position shown in FIG. 6B to the first angular position shown in FIG. 6C. When the process cartridge 11 is detached from the apparatus main body 9, it swings from the first angular position shown in FIG. 6 (c) to the second angular position shown in FIG. 6 (b).

  A process for mounting the process cartridge 11 will be described with reference to FIGS. Reference numerals 10a and 10b respectively denote downstream and upstream tip positions in the mounting direction a of the coupling shaft 10 when the coupling shaft 10 is inclined. In the process of mounting the process cartridge 11, the coupling shaft 10 shown in FIG. 6A is inclined in the mounting direction a with respect to the axis L 1 of the drum shaft 13 in advance with the axis L 2 as the second angular position.

  Since the coupling shaft 10 is inclined with respect to the axis L1 of the drum shaft 13, the tip position 10a of the coupling shaft 10 on the downstream side in the mounting direction a in the direction of the axis L1 of the drum shaft 13 is It is located closer to the drum shaft 13 than the tip 3d. The tip position 10b of the coupling shaft 10 on the upstream side in the mounting direction a is located in the direction of the driving force transmission pin 3a with respect to the tip 3d of the main body gear shaft 3.

  When the process cartridge 11 is inserted in a mounting direction a in FIG. 5 along a guide (not shown) provided in the apparatus main body 9, first, the tip position 10a on the upstream side in the mounting direction a of the coupling shaft 10 is the main body gear shaft. 3 passes through the tip 3d. Then, after passing, the conical body gear bearing surface 10f of the coupling shaft 10 or the driven projection 10g contacts the body gear shaft 3 or the driving force transmission pin 3a (FIG. 6B).

  Then, according to the mounting operation of the process cartridge 11, the axis L2 of the coupling shaft 10 is inclined so as to be parallel to the axis L1 of the drum shaft 13. Finally, the mounting position of the process cartridge 11 with respect to the apparatus main body 9 is determined. The main body gear shaft 3 and the drum shaft 13 are disposed on substantially the same straight line, and the coupling shaft 10 is at the first angular position (FIG. 6C). Then, the coupling shaft 10 and the main body gear shaft 3 are engaged.

  As described above, the coupling shaft 10 is attached so as to be inclined with respect to the axis L2 of the drum shaft 13, and the coupling shaft 10 is inclined according to the mounting operation of the process cartridge 11. That is, the coupling shaft 10 and the main body gear shaft 3 can be engaged without interfering with each other.

  Next, the driving force transmission configuration will be described with reference to FIG. In FIG. 7, reference numeral 1 denotes a main body frame constituting the apparatus main body 9. Reference numeral 2 denotes a bearing member fixed to the main body frame 1, and the bearing member 2 has a circular hole 2a for rotatably supporting the main body gear shaft 3. Reference numeral 7 denotes a drive motor. Reference numeral 8 denotes a motor gear for transmitting the driving force of the driving motor 7 to the main body gear 4. Reference numeral 5 denotes a parallel pin for transmitting the driving force from the main body gear 4 to the main body gear shaft 3. Reference numeral 6 denotes an auxiliary side plate positioned and fixed to the main body frame 1.

  First, the motor gear 8 transmits the driving force of the driving motor 7 as a driving source to the main body gear 4. The driving force of the main body gear 4 is transmitted to the main body gear shaft 3 by the parallel pins 5. A driving force is transmitted from the main body gear shaft 3 to the coupling shaft 10 by the driving force transmission pin 3a provided on the main body gear shaft 3 coming into contact with any two of the four driven projections 10g. The coupling shaft 10, the main body gear shaft 3, and the drum shaft 13 rotate substantially coaxially, whereby a driving force is transmitted from the apparatus main body 9 to a photosensitive drum (not shown).

  The process cartridge 11 is removed from the apparatus main body 9 through a process reverse to the mounting process. At this time, since the coupling shaft 10 is attached so as to be inclined with respect to the axis L1 of the drum shaft 13, the process cartridge 11 can be removed from the apparatus main body 9 without the main body gear shaft 3 and the coupling shaft 10 interfering with each other. It can be removed.

  As described above, in the configuration of Patent Document 1, the process cartridge 11 can be attached and detached without a mechanism for retracting the coupling shaft 10 in the direction of the axis L1 of the drum shaft 13 of the photosensitive drum. Therefore, the apparatus main body 9 can be reduced in size and simplified.

JP 2008-233867 A

  In Patent Document 1, when the process cartridge 11 is inserted into the apparatus main body 9 and attached, between the main body gear shaft 3 provided in the apparatus main body 9 and the coupling shaft 10 provided in the process cartridge 11, There is a possibility that misalignment of the shaft center may occur due to part accuracy. When the rotational driving force is transmitted from the drive motor 7 to the main body gear shaft 3 while the shaft center is shifted between the main body gear shaft 3 and the coupling shaft 10 for transmitting the driving force, the main body gear shaft 3 The coupling shaft 10 swings and rotates.

  In Patent Document 1, as shown in FIG. 7, the main body gear 4 is supported by being fitted to the main body gear shaft 3, so that the main body gear shaft 3 is rotated integrally with the main body gear shaft 3. Further, the shake of the main body gear 4 becomes the rotation unevenness of the main body gear 4, and the rotation unevenness is transmitted to the coupling shaft 10 on the process cartridge 11 side via the main body gear shaft 3. These affect the image forming drive and the image of the process cartridge 11. If the rotation unevenness of the main body gear 4 exceeds an allowable amount, an image defect may occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which a main body gear can rotate stably and no rotation unevenness occurs.

In order to achieve the above object, a typical configuration of an image forming apparatus according to the present invention includes a gear that is rotated by a driving force transmitted from a driving source , a gear support that rotatably supports the gear, and the gear. A shaft member that is rotated coaxially with the gear and a shaft support portion that rotatably supports the shaft member, and an engagement portion provided on the shaft member, and the apparatus main body An image is formed on the sheet material by transmitting a driving force from the driving source to the engaged portion through the engaging portion and rotating the engaged portion with the engaged portion of the cartridge mounted on the cartridge. in the image forming apparatus that performs, the gear support portion has a cylindrical portion in which the hollow portion is formed inside said shaft member is inserted into the hollow portion of the inner side of the cylinder of the cylindrical portion, wherein the gear It is supported by the outer circumferential surface of the cylindrical portion, the inner peripheral surface of the cylindrical portion before Characterized in that apart from the shaft member.

According to the above configuration, since the shaft member is inserted through the inside of the cylindrical shape and the gear is rotatably supported on the outer periphery of the cylindrical portion , even if the shaft member is misaligned, the shaft of the gear does not deviate. . Therefore, when the cartridge is inserted into the apparatus main body and mounted, even if the shaft center of the shaft member is deviated, the influence of the shaft member misalignment on the rotation of the gear is reduced. For this reason, shake that is a cause of uneven rotation of the gear can be prevented, leading to an improvement in image quality.

FIG. 3 is a perspective explanatory view illustrating a configuration of the image forming apparatus. (A) is an exploded perspective view showing a configuration of a coupling portion between a main body gear shaft and a coupling shaft in the first embodiment of the image forming apparatus according to the present invention, and (b) is a main body gear shaft and a cup in the first embodiment. It is sectional explanatory drawing which shows the structure of the coupling | bond part with a ring axis | shaft. (A) is a figure which shows the location which measured the shake amount of the main body gear, (b) is a figure which shows the result of having measured the shake amount of the main body gear. (A) is an exploded perspective view showing a configuration of a coupling portion between a main body gear shaft and a coupling shaft in the second embodiment of the image forming apparatus according to the present invention, and (b) is a main body gear shaft and a cup in the second embodiment. It is sectional explanatory drawing which shows the structure of the coupling | bond part with a ring axis | shaft. FIG. 5 is a perspective view showing a configuration of a coupling shaft provided on the process cartridge side and second transmission means for transmitting the driving force of the main body gear shaft to the coupling shaft. (A)-(c) is a figure which shows the coupling | bonding operation | movement of a main body gear shaft and a coupling shaft. FIG. 10 is an explanatory cross-sectional view illustrating a configuration of a coupling portion between a main body gear shaft and a coupling shaft in a conventional image forming apparatus.

  An embodiment when applied to a laser beam printer as an example of an image forming apparatus according to the present invention will be specifically described with reference to the drawings.

  First, the configuration of the first embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS. The same components as those of the conventional example described above with reference to FIGS. 1 and 5 to 7 are denoted by the same reference numerals, and description thereof is omitted. FIG. 1 is a perspective view showing a configuration of an image forming apparatus according to the present invention, in which a sheet material is conveyed to form an image by a process cartridge 11, and the image-formed sheet material is conveyed to a fixing device to fix an image. FIGS. 2A and 2B are an exploded perspective view and a cross-sectional explanatory view showing the configuration of the drive transmission unit of the first embodiment.

  In this embodiment, as shown in FIGS. 2A and 2B, the main body gear shaft 3 provided in the apparatus main body 9 to which the driving force is transmitted from the main body gear 4 is fixedly positioned on the main body frame 1. It is rotatably supported by a circular hole 2a which is a shaft support member provided on the bearing member 2 formed. The main body gear shaft 3 is rotatably supported by a circular hole 6 a which is a shaft support member provided on the auxiliary side plate 6 fixed to the main body frame 1 on the other side. A circular hole 2a of the bearing member 2 serving as a shaft support member and a circular hole 6a of the auxiliary side plate 6 are provided in the apparatus main body 9, and rotatably support the main body gear shaft 3.

  The main body gear 4 provided in the apparatus main body 9 to which the driving force is transmitted from the driving motor 7 is not supported by the main body gear shaft 3 as in the above-described conventional example, but is a bearing member fixed to the main body frame 1. 2 is rotatably supported by a cylindrical portion 2b, which is a gear support member provided in FIG. A cylindrical portion 2b, which is a gear support member, is provided in the apparatus main body 9, and supports the main body gear 4 in a rotatable manner. In the present embodiment, the circular hole 2a of the bearing member 2 serving as the shaft support member and the cylindrical portion 2b serving as the gear support member are provided in the bearing member 2 made of the same component.

  As for the transmission of the driving force, the driving force of the driving motor 7 which is a driving source is transmitted from the motor gear 8 to the main body gear 4, and parallel pins as first transmission means for transmitting the driving force of the main body gear 4 to the main body gear shaft 3. 5 to the main body gear shaft 3.

  The coupling shaft 10 is provided coaxially with the main body gear shaft 3 and transmits the driving force of the main body gear shaft 3 to the process cartridge 11 side (process cartridge side). Driving force transmission between the coupling shaft 10 and the main body gear shaft 3 is constituted by a driving force transmission pin 3 a provided on the main body gear shaft 3 and a driven projection 10 g provided on the coupling shaft 10. This is performed by the second transmission means.

  At that time, when the driving force is transmitted in a state where the coupling shaft 10 and the main body gear shaft 3 are not coaxial due to the influence of the component accuracy, the main body gear shaft 3 swings and rotates. In the present embodiment, the main body gear 4 is rotatably supported by the cylindrical portion 2b provided on the bearing member 2 fixed to the main body frame 1 even when the main body gear shaft 3 is swung and rotated. It is possible to reduce the influence of the shake of the shaft 3 on the main body gear 4. Further, by configuring the shaft support member of the main body gear shaft 3 and the gear support member of the main body gear 4 with the same component, it is possible to improve the image quality while preventing deterioration in assemblage due to an increase in the number of components.

  As described above, the main body gear 4 is fitted and supported in a rotatable manner by the cylindrical portion 2b provided on the bearing member 2 fixed to the main body frame 1. Accordingly, since the influence of the shake of the main body gear shaft 3 on the rotation of the main body gear 4 can be suppressed, the shake that is a cause of uneven rotation of the main body gear 4 can be prevented, and a high-quality image forming apparatus is provided. I can do it.

  Here, the result of measuring the deflection of the main body gear 4 is shown in FIG. 3B, Comparative Example A shows a conventional configuration in which the main body gear 4 shown in FIG. The embodiment B has a configuration in which the main body gear 4 shown in FIG. 2 is rotatably fitted and supported on a cylindrical portion 2b provided on the bearing member 2 fixed to the apparatus main body 9. As shown in FIG. 3 (a), the deflection of the main body gear 4 is measured in a time-series manner by using one point on the end surface of the main body gear 4 perpendicular to the rotation axis as a measurement location 4a. It was measured.

  The graph shown in FIG. 3B shows the vibration of the main body gear 4 for about three rounds, and the main body gear 4 is periodically shaken. According to the measurement results shown in FIG. 3B, the configuration of the present embodiment B has less deflection of the main body gear 4 and less deflection of the main body gear 4 than the configuration of the conventional comparative example A. There was found. That is, in the embodiment B, the shake of the main body gear 4 that affects the rotation unevenness is further reduced, and as a result, high image quality is obtained as compared with the configuration of the conventional comparative example A.

  Next, the configuration of the second embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS. In addition, what was comprised similarly to the said 1st Embodiment and the prior art example mentioned with reference to FIG. 1, FIG. 5-FIG. 7 attaches | subjects the same code | symbol, and abbreviate | omits description.

  4 (a) and 4 (b), 14 is a bearing side plate which is a shaft support member which is positioned and fixed to the main body frame 1 and rotatably supports the main body gear shaft 3, and 14a is provided on the bearing side plate 14. This is a circular hole 14 a for supporting the main body gear shaft 3. A circular hole 14a provided in the bearing side plate 14 which is a shaft support member is provided in the apparatus main body 9 and supports the main body gear shaft 3 to be rotatable.

  In the present embodiment, the portion supporting the main body gear shaft 3 is not the circular hole 2a provided in the bearing member 2 which is a shaft support member as in the first embodiment. One is constituted by a circular hole 14a provided in the bearing side plate 14 which is a shaft support member, and the other is constituted by a circular hole 6a provided in the auxiliary side plate 6 which is a shaft support member, and is rotatably supported. The main body gear 4 is rotatably supported by a cylindrical portion 2 b provided on the bearing member 2. Accordingly, in the present embodiment as well, since the main body gear 4 is not supported by the main body gear shaft 3 as in the conventional example, the influence of the shake of the main body gear shaft 3 on the rotation of the main body gear 4 is reduced, and the image quality is improved. it can.

2 ... Bearing member 2a ... Circular hole (shaft support member)
2b ... Cylindrical part (gear support member)
3 ... body gear shaft 3a ... driving force transmission pin (second transmission means)
4 ... body gear 5 ... parallel pin (first transmission means)
7 ... Drive motor 9 ... Main unit
10… Coupling shaft
10g ... driven protrusion (second transmission means)
11 Process cartridge

Claims (8)

A gear that rotates when a driving force is transmitted from a driving source;
A gear support for rotatably supporting the gear;
A driving force is transmitted from the gear, and a shaft member that rotates coaxially with the gear;
A shaft support portion for rotatably supporting the shaft member;
Have
Driving force from the driving source to the engaged portion via the engaging portion in a state where the engaging portion provided on the shaft member is engaged with the engaged portion of the cartridge mounted on the apparatus main body. In an image forming apparatus that forms an image on a sheet material by transmitting and rotating
The gear support portion includes a cylindrical portion having a hollow portion formed therein, the shaft member is inserted into a hollow portion inside the cylindrical portion of the cylindrical portion, and the gear is disposed on an outer peripheral surface of the cylindrical portion. An image forming apparatus , wherein an inner peripheral surface of the cylindrical portion is supported and is separated from the shaft member . The image forming apparatus according to claim 1, wherein the shaft support portion is located on both sides of the cylindrical portion in the axial direction of the shaft member . The image forming apparatus according to claim 2, wherein one of the shaft support portions positioned on both sides of the cylindrical portion is configured integrally with the gear support portion . 4. The image forming apparatus according to claim 3, wherein one of the shaft support portions located on both sides of the cylindrical shape portion is a circular hole formed in the gear support portion . The image forming apparatus according to claim 2, wherein the shaft support portions positioned on both sides of the cylindrical portion are configured separately from the gear support portion . The image forming apparatus according to claim 1, wherein the gear and the shaft member are connected by a pin . The cartridge, an image forming apparatus according to any one of claims 1 to 6, characterized in that it is mounted to move in the direction perpendicular to the axial direction of the shaft member to the apparatus body. The image forming apparatus according to claim 7 , wherein the engaged portion is swingable with respect to a main body of the cartridge.

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