JP2007079191A - Driving device for image forming apparatus, image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an idler pulley from moving in a stretching direction by a moment force transmitted through a fastening member when fixing an idler pulley support member to a casing.
An idler pulley 104 is rotatably attached to a support shaft 106 on a support member 105. The support member 105 is fixed to a housing or the like (not shown) through the fastening member 108 at the sliding hole 107 provided in the support member 105. When fixing, an appropriate initial tension is applied to the timing belt 103 by the pressure member 109. The support member 105 has a contact surface A to the housing or the like, and is generated when the fastening member 108 is tightened by pressing the contact surface A with a finger or the like and fixing the support member 105 against the housing or the like. The moment member M suppresses the fastening member 108 from moving in the Z direction, that is, the direction perpendicular to the paper surface.
[Selection] Figure 1

Description

  The present invention relates to a drive device for an image forming apparatus and an image forming apparatus using the same.

  In a drive transmission device for an image forming apparatus that uses a timing pulley, an appropriate tension is applied to prevent the timing pulley from skipping teeth. In particular, with respect to a rotating body driving mechanism for an image forming apparatus such as a copying machine or a printer using an electrophotographic system, if the tension is too large, non-variable or vibration generated in a non-driving part other than the rotating body causes the timing pulley to move. This is because noise transmitted to the rotating body through the rotation increases, and the speed unevenness occurs in the peripheral speed of the sheet conveying member and the photosensitive member.

  Such speed unevenness may adversely affect the image to be formed. In particular, the influence is large in the photoreceptor driving system. Therefore, the tension applied to the timing pulley must be appropriate.

  The tension applied to the timing pulley is applied by an idler pulley via a spring, and the tension is adjusted by the spring. After tension adjustment, the idler pulley is fixed to the housing, but when the moment force at the time of fixing is applied to the idler pulley support, the position of the idler pulley may move and differ from the adjustment value. .

Patent Document 1 discloses a photosensitive drum driving device using a timing belt, which is applied with an initial tension by a tension coil spring and then fixed with a screw on a surface of a casing parallel to the adjustment direction of an idler pulley (with a pulley). A technique for providing an elastic member between support members is disclosed. Patent Document 2 discloses an automatic belt tension adjusting mechanism that fixes a pulley support plate to a bracket with a right-angle bend fixed to a side plate with a plane parallel to the adjustment direction of the pulley. Further, Patent Document 3 discloses a hose pulley bracket that fixes the bracket to the casing on a surface perpendicular to the longitudinal direction of the pulley shaft fixing long hole. Patent Document 4 describes an example of a method of assembling a gear and a shaft, which is pressed and fixed from above after positioning.
Japanese Patent Laid-Open No. 2003-345177 Japanese Unexamined Patent Publication No. 08-093868 Patent No. 02720708 Japanese Patent Laid-Open No. 11-347858

  In view of such a conventional problem, the present invention prevents the idler pulley from moving in the stretching direction, thereby preventing an extra tension from being applied to the timing pulley and obtaining a better image. An object of the present invention is to provide an image forming apparatus using the same.

The present invention prevents the idler pulley from moving in the stretching direction by the moment force transmitted through the fastening member when the idler pulley support member is fixed to the housing, and prevents the tension pulley from being applied with extra tension. To do.

  Specifically, a drive device for an image forming apparatus according to claim 1 of the present invention is a drive device for an image forming apparatus such as a copying machine or a printer, and timings the drive connection between the drive motor and the rotating body. In a driving device that uses a belt, an idler pulley support member that applies an appropriate initial tension to the timing belt and is fixed to a housing is provided with a contact surface perpendicular to the idler pulley movement direction, and the contact surface is The idler pulley support member can be fixed to the casing while being pressed against the casing.

  According to a second aspect of the present invention, in the drive device for an image forming apparatus according to the first aspect, the contact surface is a planar portion extending over both blades of the idler pulley support member.

  According to a third aspect of the present invention, in the driving device for an image forming apparatus according to the first aspect, the idler pulley support member and the housing extend along the idler pulley moving direction in parallel with the idler pulley. A contact surface erected perpendicular to the fixing direction is provided, and the idler pulley support member can be fixed to the housing while pressing the contact surface against the housing.

  According to a fourth aspect of the present invention, in the drive device for an image forming apparatus according to the second aspect, the idler pulley is attached to the housing via a support member, and the idler pulley is attached to the support member. A contact surface perpendicular to a fixing direction of a fastening member for attaching the idler pulley to the support member is formed, and the contact surface can be fixed while being pressed against the support member. .

  An image forming apparatus according to a fifth aspect of the present invention is characterized by using the drive device for an image forming apparatus according to any one of the first to fourth aspects.

  According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect, the driving target of the driving device is an image carrier such as a photosensitive member.

  The present invention prevents the idler pulley from moving in the stretching direction due to the moment force transmitted through the fastening member when the idler pulley support member is fixed to the housing, and prevents an extra tension from being applied to the timing pulley. It becomes possible to do.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  FIG. 1 is a sectional view conceptually showing an embodiment of an image forming apparatus according to the present invention. The image forming apparatus according to the present embodiment mainly includes a reading unit 11 that reads a document, an image forming unit 12 that forms an image, an automatic document feeder (ADF) 13, a document discharge tray 14 that stacks documents sent from the ADF 13, The sheet feeding unit 19 includes sheet feeding cassettes 15 to 18 and a sheet discharge unit (sheet discharge tray 20) for stacking recording sheets.

  Then, when the document D is set on the document table 21 of the ADF 13 and an operation on an operation unit (not shown), for example, a press operation of a print key is performed, the uppermost document D is sent out in the direction of the arrow B1 by the rotation of the pickup roller 22. Then, by the rotation of the document conveying belt 23, the paper is fed onto the contact glass 24 fixed to the image reading unit 11, and stops there. The image of the document D placed on the contact glass 24 is read by a reading device 25 located between the image forming unit 12 and the contact glass 24. The reading device 25 includes a light source 26 that illuminates the document D on the contact glass 24, an optical system 27 that forms an image of the document, a photoelectric conversion element 28 that includes a CCD that forms an image of the document, and the like. After the image reading is completed, the document D is transported in the direction of the arrow B2 by the rotation of the document transport belt 23 and discharged onto the document discharge tray 14. In this way, the document D is fed one by one onto the contact glass 24 and the document image is read by the image reading unit 11.

  On the other hand, inside the image forming unit 12, a photoconductor 30 as an image carrier is disposed. The photosensitive member 30 is driven to rotate clockwise in the drawing, and the surface is charged to a predetermined potential by the charging device 31. Further, the writing unit 32 emits a laser beam L that is light-modulated in accordance with image information read by the reading device 25, and the surface of the charged photoreceptor 30 is exposed with the laser beam L, whereby the photoreceptor is exposed. An electrostatic latent image is formed on the surface 30. When the electrostatic latent image passes through the developing device 33, the electrostatic latent image is transferred to the recording medium P fed between the photosensitive member 30 and the transfer device 34 by the opposing transfer device 34. The surface of the photoconductor 30 after the toner image is transferred is cleaned by a cleaning device 35.

  A plurality of paper feed cassettes 15 to 18 arranged below the image forming unit 12 contain recording media P such as paper, and the recording media P is fed from any of the paper feed cassettes 15 to 18 in the direction of arrow B3. The toner image formed on the surface of the photoreceptor 30 as described above is transferred onto the surface of the recording medium P. Next, the recording medium P is passed through the fixing device 36 in the image forming apparatus as indicated by an arrow B4, and the toner image transferred to the surface of the recording medium P by the action of heat and pressure is fixed. The recording medium P that has passed through the fixing device 36 is conveyed by the discharge roller pair 37, discharged to the discharge tray 20 as indicated by an arrow B5, and stacked.

  FIG. 2 is a front view schematically showing a first embodiment of the driving apparatus according to the present invention. In this figure, an idler pulley is used to apply initial tension to a timing belt 103 that connects a motor side timing pulley 101 that rotates by a gear connection from a drive motor (not shown) and a rotating body side pulley 102 such as the photosensitive drum 30. 104 is provided.

  The idler pulley 104 is rotatably attached to a support shaft 106 on the support member 105. The support member 105 is configured to be fixed to a housing or the like (not shown) via a fastening member 108 at a portion of the sliding hole 107 provided in the support member 105. When the support member 105 is fixed, the pressure member 109 is fixed. Thus, an appropriate initial tension is applied to the timing belt 103. Note that the support member 105 has contact surface portions A and A to a housing or the like (not shown), and is fixed while pressing the contact surface portion A with an operator's finger or the like while pressing the support member 105 against the housing or the like. By doing so, it is possible to suppress the fastening member 108 from moving in the Z direction, that is, the direction perpendicular to the paper surface, from the moment force M generated when the fastening member 108 is tightened.

  That is, in this example, when the support member 105 of the idler pulley 104 is fixed to the housing, the idler pulley 104 is prevented from moving in the stretching direction of the timing belt 103 due to the moment force M transmitted through the fastening member 108. This prevents an unnecessary tension from being applied to the timing pulley 101.

  3 and 4 are a front view and a plan view showing a second embodiment of the present invention. In these drawings, the idler pulley 104 is attached to the back surface of the support member 110 of the motor side timing pulley 101. Therefore, in this embodiment, a contact surface B parallel to the sliding hole 107 and perpendicular to the fastening member 108 fixing direction is formed on the support member 110 and the support member 105b of the idler pulley 104, and the contact surface B is used as an operator's finger or the like. By fixing the supporting member 105b while pressing in the X direction, it is possible to suppress the idler pulley 104 from moving in the Z direction.

  In particular, when the above-described configuration is used in the photosensitive drum driving device, this effect is great. Therefore, a drum driving device including a photosensitive drum driving motor 111, a photosensitive drum driving pulley 113 including a photosensitive drum driving pulley, a timing belt, and an idler pulley, a photosensitive drum driving pulley 113, and a photosensitive shaft 114 shown in FIG. In FIG. 4, the output image was compared between the case where the idler pulley support member was fixed while being pressurized and the case where it was not. When the support member was fixed while being pressed, image unevenness hardly occurred, whereas when the support member was fixed without being pressed, image unevenness occurred. As a comparison between pressurization and non-pressurization, the movement after fixing the support member during non-pressurization was 0.9 mm.

  Further, with respect to the difference in tension of the timing belt 103, the force required to push down the timing belt 103 by 2.5 mm was 0.69N when no pressure was applied to 0.29N when pressure was applied. Therefore, by fixing the supporting member while applying pressure, the movement of the supporting member due to the moment force at the time of fixing is suppressed, and image unevenness that increases in proportion to the pressure applied to the timing belt 103 from some place is prevented. Is possible.

  That is, in the driving device according to the present invention, when the idler pulley that applies initial tension to the timing belt is fixed to the housing or the like via the elastic member, the idler pulley support member is fixed to the housing while being pressed. Thus, since the idler pulley support member can be prevented from moving in the timing belt pressurizing direction due to the moment force generated when the fastening member is fixed, the pressure applied to the timing belt is increased and transmitted to the rotating body via the timing belt. It is possible to prevent the rotating body speed unevenness due to load fluctuations, vibrations and the like from increasing.

  In addition, when fixing the idler pulley support member to the housing, etc., the contact surface to be pressed is configured parallel to the sliding hole and perpendicular to the mounting direction, so that it can be fixed even if it exists on the back of today's equivalent mounting surface In this case, it can be easily pressurized.

  Furthermore, by using it particularly in the photosensitive member driving device, it is possible to prevent occurrence of unevenness in the image due to unevenness of the rotating body speed transmitted to the rotating body via the timing belt and obtain a good image.

1 is a cross-sectional view conceptually showing an embodiment of an image forming apparatus according to the present invention. 1 is a front view schematically showing a first embodiment of a drive device according to the present invention. Front view showing a second embodiment of the present invention Plan view The perspective view which shows the example which used this invention for the photoreceptor drum drive device

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Reading unit 12 Image forming part 13 Automatic document feeder (ADF)
14 Document discharge tray 15 to 18 Paper feed cassette 19 Paper feed unit 20 Paper discharge unit (discharge tray)
21 Document Plate D Document 22 Pickup Roller 23 Document Conveying Belt 24 Contact Glass 25 Reading Device 26 Light Source 27 Optical System 28 Photoelectric Conversion Element 30 Photoconductor 31 Charging Device 32 Writing Unit 33 Developing Device 34 Transfer Device 35 Cleaning Device 36 Fixing Device 37 Ejection Roller pair 101 Motor side timing pulley 102 Rotating body side pulley 103 Timing belt 104 Idler pulley 105 Support member 106 Support shaft 107 Sliding hole 108 Fastening member 109 Pressure member 110 Support member 105b Support member 111 Photosensitive drum drive motor 112 Photoconductor Pulley unit 113 Photoreceptor drum drive pulley 114 Photoreceptor shaft A Contact surface

Claims (6)

A driving device for an image forming apparatus such as a copying machine or a printer, in which a driving motor and a rotating body are driven and connected by a timing belt, and an appropriate initial tension is applied to the timing belt to The idler pulley support member to be fixed has a contact surface perpendicular to the moving direction of the idler pulley, and the idler pulley support member can be fixed to the housing while pressing the contact surface against the housing. A drive device for an image forming apparatus. The drive device for an image forming apparatus according to claim 1, wherein the contact surface is a planar portion extending on both blades of the idler pulley support member. 2. The driving device for an image forming apparatus according to claim 1, wherein the contact extends from the idler pulley support member and the housing along a direction in which the idler pulley moves in parallel and is erected perpendicularly to the idler pulley fixing direction. A drive device for an image forming apparatus, characterized in that a surface is provided and the idler pulley support member can be fixed to the housing while pressing the contact surface against the housing. The drive device for an image forming apparatus according to claim 2, wherein the idler pulley is attached to the housing via a support member, and the idler pulley is attached to a back surface of the support member. A drive device for an image forming apparatus, wherein a contact surface perpendicular to a fixing direction of a fastening member for attaching the idler pulley to the member is formed, and the contact surface can be fixed while being pressed against the support member. An image forming apparatus using the drive device for an image forming apparatus according to claim 1. 6. The image forming apparatus according to claim 5, wherein the driving target of the driving device is an image carrier such as a photosensitive member.