JP2008090119A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can maintain the quality of an output image, and also achieves enhancement in operability of attaching/detaching a photoreceptor unit to/from an image forming apparatus main body. <P>SOLUTION: The image forming apparatus 10 includes: the image forming apparatus main body 12; the photoreceptor unit 26 provided freely attachably/detachably to/from the image forming apparatus main body 12 and including a plurality of photoreceptors 40; an optical writing device 56 for irradiating the plurality of photoreceptors 40 with light and writing a latent image; and a positioning means 72 for positioning the photoreceptor unit 26 relative to the optical writing device 56. The positioning means 72 includes: a positioning part 74 formed in the photoreceptor unit 26; a part to be positioned 76 formed in the image forming apparatus main body 12; and a grip part 78 to grip the photoreceptor unit 40 when it is attached/detached to/from the image forming apparatus main body 12. The part to be positioned 76 and the positioning part 74 abut on each other with the energizing force of the grip part 78, then, positioned. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  There is a xerographic system as an image forming apparatus such as a copying machine, a printer, and a facsimile. As an example of this xerographic system, the surface of a plurality of photoconductors is uniformly charged by a charging device and, for example, optical writing is performed on the photoconductor. A latent image is formed by the apparatus, the latent image formed on the photosensitive member is visualized as a toner image by a developing device, and the visualized toner image is transferred to a sheet by a transfer roll of a transfer unit, There is known one in which the transferred toner image is fixed on a sheet by a fixing device. In such an image forming apparatus, in order to obtain an image of stable quality, it is necessary to reduce a shift in the relative positional relationship between the plurality of photoconductors and the optical writing device. Therefore, there has been known one in which a positioning portion is formed in a main body frame and a plurality of photosensitive drums are positioned in the positioning portion (for example, Patent Document 1).

JP-A-2001-142274

  However, the prior art has a problem in that the urging means is provided for each of the plurality of photoconductors, which is costly.

  An object of the present invention is to provide an image forming apparatus that solves the above-described conventional problems, maintains the quality of an output image, and improves the detachability of the photosensitive unit.

  In order to achieve the above object, a latent image is formed by irradiating light to the image forming apparatus main body, a photoconductor unit detachably provided on the image forming apparatus main body, and having a plurality of photoconductors. An optical writing device for writing, and positioning means for positioning the photosensitive unit with respect to the optical writing device, the positioning unit being provided on a positioning portion formed on the photosensitive unit and the main body of the image forming apparatus A positioning portion to be formed, and a gripping means for gripping when the photosensitive unit is attached or detached, and the positioning portion and the positioning portion are brought into contact with each other by the urging force of the gripping means for positioning. In the image forming apparatus.

  Preferably, the gripping means includes a gripping part main body and biasing means for biasing the positioning part with respect to the positioned part.

  Preferably, the biasing means forms a space for gripping the grip portion main body.

  Preferably, the positioning portion includes a plurality of support shafts that support the plurality of photoconductors.

  Preferably, the positioned portion is formed so as to contact at least two of the plurality of support shafts.

  Preferably, the photoconductor unit includes a drive gear that is provided on one side surface of the photoconductor unit and drives the plurality of photoconductors, and the positioning unit includes a gear shaft that supports the drive gear.

  Preferably, the image forming apparatus main body includes an input gear that meshes with the drive gear, and the positioned portion is in contact with a direction that receives a force generated by the meshing of the input gear and the drive gear. Is formed.

  Preferably, the positioning portion includes a convex portion formed on a side surface of the photoconductor unit.

  Suitably, the said to-be-positioned part is formed so that it may contact | abut from the downward direction of the said convex part.

  Preferably, the image forming apparatus main body has a moving unit movably provided, and the gripping means is biased by the movement of the moving unit.

  According to the present invention, since the positioned portion and the positioning portion are brought into contact with each other by the urging force of the gripping means, the relative positional relationship between the plurality of photoconductors and the optical writing device is suppressed, and the output The image quality can be maintained and the detachability of the photosensitive unit can be improved.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12. A sheet supply device 14 is disposed at a lower portion of the image forming apparatus main body 12, and a sheet discharge unit 16 is disposed at the upper portion of the image forming apparatus main body 12. Is formed.

  The sheet feeding device 14 includes a sheet cassette 18, and a large number of sheets are stacked and accommodated in the sheet cassette 18. A feed roll 20 is disposed on one upper end of the sheet cassette 18, and a retard roll 22 is provided facing the feed roll 20. The uppermost sheet of the sheet cassette 18 is picked up by the feed roll 20, and the sheet is rolled and conveyed by the cooperation of the feed roll 20 and the retard roll 22.

  The sheet conveyed from the sheet cassette 18 is temporarily stopped by the registration roller 24, and at a predetermined timing, between the photosensitive unit 26 and the transfer unit 28, which will be described later, and through the fixing device 30, the sheet discharge unit 16 by the discharge roller 32. Is discharged.

  In the image forming apparatus main body 12, a photosensitive unit 26, a transfer unit 28, a power supply unit 34, and a control unit 36 are arranged. In the photoconductor unit 26, for example, four photoconductors 40 are rotatably supported by the photoconductor unit main body 38. Around each photoconductor 40, a charging device 42 as a charging means provided with a charging roll for uniformly charging the photoconductor 40, and a latent image written on each photoconductor 40 is developed with a developer (toner). A developing device 44 as a developing means, a static eliminating device 46 for neutralizing the photoreceptor 40 after transfer, and a cleaning device 48 as a developer removing means for removing the developer remaining on the photoreceptor 40 after the transfer. Have The photoconductor unit 26 includes four photoconductors 40, a charging device 42, a developing device 44, a charge removal device 46, and a cleaning device 48, and is detachable from the image forming apparatus main body 12.

  The four toner boxes 50 are connected to the back side of the photoconductor unit 26. Each toner box 50 is for magenta, yellow, cyan, and black, and a toner supply unit 52 and a toner recovery unit 54 are integrated. The toner supply unit 52 is connected to the developing unit 44 to supply each color toner to the developing unit 44, and the toner recovery unit 54 is connected to the cleaning device 48 to collect each color toner.

  Each of the optical writing devices 56 is composed of a laser exposure device, and is arranged on the back side of the photoconductor unit 26 at a position corresponding to each photoconductor 40, and irradiates the uniformly charged photoconductor 40 with a laser. Thus, a latent image is formed.

  The transfer unit 28 is on the front side of the photoconductor unit 26 and is arranged in the vertical direction facing the photoconductor unit 26. In the transfer unit 28, a transport belt 60 is hung on two support rolls 58 provided in the vertical direction, and a transfer roll 62 is provided to face each photoconductor 40 with the transport belt 60 interposed therebetween. . The transfer unit 28 is movably provided in the image forming apparatus main body 12 and is used as a moving unit.

  Therefore, each photoconductor 40 is uniformly charged by the charging device 42, a latent image is formed by the optical writing device 56, and the latent image is visualized by toner by the developing device 44. The toner images formed on the respective photoconductors 40 are transferred to the conveyed sheet by the transfer roller 62 of the transfer unit 28 in order from below, and are fixed to the sheet by the fixing device 30.

  Details of the photoreceptor unit 26 are shown in FIGS. As shown in FIGS. 2 and 3, the photoconductor unit 26 includes a photoconductor unit main body 38. The photoconductor unit main body 38 has a pair of opposing side surface portions (first side surfaces) formed in a substantially vertical direction. Part 38a and second side part 38b). A plurality of support shafts 40 a are disposed on the first side surface portion 38 a and the second side surface portion 38 b, and end portions of the support shaft 40 a are provided so as to protrude outside the photoconductor unit 26. . These support shafts 40 a support the respective photoconductors 40 arranged in the photoconductor unit 26. The convex portion 64 (shown in FIG. 2) is formed in, for example, a cylindrical shape, is provided on the second side surface portion 38b, and is disposed at a position facing a gear shaft 70 of a drive gear 66a described later.

  As shown in FIGS. 3A and 3B, the drive transmission device 66 is provided on the side surface 38 a of the photoconductor unit main body 38. The drive transmission device 66 includes a drive gear 66 a, a connection gear 66 b, and an input gear 68, and transmits the drive force of a drive source (not shown) to each photoconductor 40.

  The input gear 68 is rotatably provided in the image forming apparatus main body 12 and is connected to a drive source (not shown) such as a motor. The input gear 68 is disposed at a position where the input gear 68 meshes with the drive gear 66a when the photosensitive unit 26 is attached to the image forming apparatus main body 12, and transmits the drive force to the drive gear 66a. The drive gear 66a has a gear shaft 70 provided at the center of the drive gear 66a. The drive shaft 66a is rotatably provided on the first side surface 38a of the photoreceptor unit main body 38 by the gear shaft 70. The drive gear 66a is disposed so as to mesh with the two connecting gears 66b and 66b, and the driving force transmitted from the input gear 68 is transmitted to the two connecting gears 66b and 66b. The coupling gears 66b and 66b are arranged to mesh with a photoconductor gear (not shown) fixed to one end of each photoconductor 40, and rotate the four photoconductors 40 at substantially the same speed.

FIG. 4 shows the photosensitive unit 26 mounted on the image forming apparatus main body 12.
As shown in FIG. 4, the positioning means 72 has a positioning portion 74 and a positioned portion 76. The positioning unit 74 includes the plurality of support shafts 40 a, the gear shaft 70, and the convex portions 64 described above, and is provided in the photoconductor unit 26. The positioned portion 76 is formed in the image forming apparatus main body 12, and includes a first positioned portion 76a, a second positioned portion 76b, a third positioned portion 76c, and a fourth positioned portion 76d. .

  As shown in FIG. 4A, the first positioned portions 76a and 76a have substantially vertical surfaces, and at least two support shafts project from the first side surface portion 38a of the photoconductor unit main body 38. It is formed so as to be in contact with the optical writing device 56 side of 40a. The second positioned portion 76b is formed in a substantially L shape having a substantially vertical plane and a substantially horizontal plane, and a force generated by the engagement between the input gear 68 and the drive gear 66a (arrow F1 in FIG. 4A). ) Contact from the direction of receiving. That is, the second positioned portion 76b is in contact with the optical writing device 56 side and the lower side of the gear shaft 70 of the drive gear 66a, and is between the shafts of the gear shaft 70 of the drive gear 66a and the support shaft of the input gear 68. The distance (distance d2 in FIG. 4A) is positioned.

  As shown in FIG. 4B, the third positioned portions 76c and 76c have substantially vertical surfaces, and at least two support shafts project from the second side surface portion 38b of the photoconductor unit main body 38. It is formed so as to be in contact with the optical writing device 56 side of 40a. In this example, the third positioning portions 76c and 76c are formed so as to come into contact with, for example, the support shaft 40a of the photoreceptor 40 disposed at the uppermost portion and the support shaft 40a of the photoreceptor 40 disposed at the lowermost portion. Has been. The fourth positioned portion 72d has a substantially horizontal plane and comes into contact with the convex portion 64 of the side surface portion 38b from below.

  When the photosensitive unit 26 is mounted on the image forming apparatus main body 12, the first positioned portion 76a, the support shaft 40a, and the second positioned portion 76b are provided on the first side surface portion 38a side of the photosensitive unit main body 38. And the gear shaft 70 come into contact with each other. On the other hand, on the second side surface portion 38b side, the third positioned portion 76b and the support shaft 40a, and the fourth positioned portion 76d and the convex portion 64 abut.

  When the first positioned portion 76a and the support shaft 40a and the third positioned portion 72c and the support shaft 40a come into contact with each other, the photoconductor unit 26 is in the axial direction of the photoconductor 40 with respect to the image forming apparatus main body 12. In the horizontal direction, that is, in the magnification direction of the optical writing device 56. As a result, the distance between the optical writing device 56 and the photoconductor 40 (d1 in FIGS. 4A and 4B) is substantially equal in each of the four photoconductors 40 provided in the photoconductor unit 26. The relative positional shift in each photoconductor 40 is suppressed, and the quality of the output image is maintained.

  Further, when the second positioned portion 76b and the gear shaft 70, and the fourth positioned portion 72d and the convex portion 64 come into contact with each other, the photosensitive unit 26 is positioned on the image forming apparatus main body 12 in the gravity direction. .

  A gripping portion 78 is shown in FIGS. As shown in FIG. 5, the gripping portion 78 has a gripping portion main body 80 and is provided in the vicinity of both side portions on the transfer unit 28 side of the photoconductor unit main body 38. Both end portions of the grip portion main body 80 are slidably engaged with groove portions 38 c formed in the photoconductor unit main body 38, and the grip portion main body 80 is perpendicular to the axial direction of the photoconductor 40 and substantially horizontal. It can be moved in the direction.

  The groove portions 38c, 38c are formed at positions corresponding to the support shaft 40a of the photoconductor 40 disposed at the top and the support shaft 40 of the photoconductor 40 disposed at the bottom. The claw portions 80a are formed at both end portions of the grip portion main body 80, and prevent the grip portion main body 80 from coming off from the groove portion 38c. Coil springs 84 and 84 as urging means are disposed in the groove portions 38 c and 38 c and provided between the support shafts 40 a and 40 a and both ends of the gripping portion main body 80.

  As shown in FIG. 6A, when the photosensitive unit 26 is attached to the image forming apparatus main body 12, the positioned portions 76a and 76a and the support shafts 40a and 40a come into contact with each other. Subsequently, when the transfer unit 28 is mounted on the image forming apparatus main body 12, the transfer unit 28 and the gripping part main body 80 come into contact with each other, and the gripping part main body 80 is on the photosensitive member 40 side (the arrow in FIG. 6A). (A direction). At this time, the coil spring 84 is compressed and biases the support shaft 40a against the positioned portion 76a (arrow F2 in FIG. 6A). That is, the gripping portion 78 is biased by the movement of the transfer unit 28 as a moving unit. As a result, the photosensitive unit 26 is reliably positioned with respect to the image forming apparatus main body 12 in a direction perpendicular to the axial direction of the photosensitive body 40 and in a substantially horizontal direction, that is, in the magnification direction of the optical writing device 56.

  As shown in FIG. 6B, when the mounting of the transfer unit 28 to the image forming apparatus main body 12 is released, the coil springs 84 and 84 attach both end portions of the grip portion main body 80 to the support shafts 40a and 40a. To force. The grip portion 78 urged by the coil springs 84 and 84 moves in the front direction of the image forming apparatus main body 12 (in the direction of arrow B in FIG. 6B), and between the photoconductor unit main body 38 and the grip portion 78. A space (space d3 in FIG. 6B) for gripping the grip portion main body 80 is formed. That is, the space between the photoconductor unit main body 38 and the gripping portion 78 after the gripping portion 78 moves (the space d3 in FIG. 6A) is the photoconductor unit main body 38 and the gripping portion before the gripping portion 78 moves. It is enlarged compared with 78 (space d3 in FIG. 6A). Thereby, the attaching / detaching operation of the photosensitive unit 26 with respect to the image forming apparatus main body 12 becomes easy, and the operability is improved.

  As described above, the present invention can be used for an image forming apparatus that needs to maintain the quality of an output image and improve the detachability of the photosensitive unit.

1 is a side view showing an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view showing a photoconductor unit according to an embodiment of the present invention. 2A and 2B show a photoreceptor unit according to an embodiment of the present invention, in which FIG. 1A is a perspective view of the photoreceptor unit, and FIG. 2B is a side view of a drive transmission device of the photoreceptor unit. 2A and 2B show a state in which a photosensitive unit according to an embodiment of the present invention is positioned, in which FIG. 3A is a side view seen from the first side face side, and FIG. 2B is a side view seen from the second side face side. 2A and 2B show a gripping portion of a photoreceptor unit according to an embodiment of the present invention, in which FIG. 1A is a side view seen from the first side face side, and FIG. 2A and 2B show a gripping portion of a photosensitive unit according to an embodiment of the present invention, in which FIG. 1A is a side view illustrating a state where the gripping portion is biased by a transfer unit, and FIG. It is a side view which shows a state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 26 Photosensitive unit 28 Transfer unit 38 Photosensitive unit main body 40 Photosensitive member 40a Support shaft 56 Optical writing device 64 Convex part 66 Drive transmission device 66a Drive gear 68 Input gear 70 Gear shaft 72 Positioning means 74 Positioning part 76 Positioned part

Claims (10)

An image forming apparatus main body;
A photoreceptor unit detachably provided on the image forming apparatus main body, and having a plurality of photoreceptors;
An optical writing device for irradiating the plurality of photosensitive members with light to write a latent image;
Positioning means for positioning the photosensitive unit with respect to the optical writing device;
Have
The positioning means includes a positioning portion formed on the photoconductor unit, a positioned portion formed on the image forming apparatus main body, and a gripping means for gripping when the photoconductor unit is attached or detached. An image forming apparatus characterized in that the positioning portion and the positioning portion are brought into contact with each other by the urging force of the gripping means.   The image forming apparatus according to claim 2, wherein the gripping unit includes a gripping unit main body and a biasing unit that biases the positioning unit with respect to the positioned unit.   The image forming apparatus according to claim 3, wherein the biasing unit forms a space for gripping the grip portion main body.   The image forming apparatus according to claim 1, wherein the positioning unit includes a plurality of support shafts that support the plurality of photosensitive members.   The image forming apparatus according to claim 4, wherein the positioned portion is formed so as to contact at least two of the plurality of support shafts.   6. The photoconductor unit according to claim 1, further comprising a drive gear that is provided on one side surface of the photoconductor unit and drives the plurality of photoconductors, and the positioning unit includes a gear shaft that supports the drive gear. Or an image forming apparatus.   The image forming apparatus main body includes an input gear that meshes with the drive gear, and the positioned portion is formed so as to contact from a direction that receives a force generated by the meshing of the input gear and the drive gear. The image forming apparatus according to claim 6.   The image forming apparatus according to claim 1, wherein the positioning portion includes a convex portion formed on the photoconductor unit.   The image forming apparatus according to claim 8, wherein the positioned portion is formed so as to contact from below the convex portion.   The image forming apparatus according to claim 1, further comprising a moving unit movably provided in the image forming apparatus body, wherein the gripping unit is biased by the movement of the moving unit.

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