JP2004044756A - Rotation body driving mechanism and image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation body driving device capable of easily adjusting a contact pressure or a gap between opposing parts of the rotation body and an opposing member, e.g., a contact pressure or a gap between the opposing parts of a development roller and a light-sensitive body, to a constant value. <P>SOLUTION: A pair of driven gears 35 is displaced in a reverse direction along a tooth streak direction of the driving gear 34 comprising a pair of helical gears by moving a driving shaft 33 of a pair of driving gears 34 to a left side or a right side along a rotation center axis direction. A rotation shaft 38 of the development roller 22 provided with the driven gear 35 is pivoted by this displacement and the contact pressure or the gap at both ends of the opposing part of the light-sensitive body and the development roller 22 is varied. Thereby, an inclination of the development roller 22 against the light-sensitive body can be relatively easily corrected in a short time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention rotationally drives the rotating body in a state where the support of the rotating body opposed to the facing member is displaced toward the facing member by a driving tangential force at the time of driving rotation of the drive gear. The present invention relates to a rotating body driving device. For example, the present invention relates to a rotator driving device used as a driving device for rotationally driving a developer carrier opposed to an image carrier in an image forming apparatus such as a copying machine, a facsimile, and a printer.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 2001-83801 discloses an "image forming apparatus" as an image forming apparatus using the above-mentioned rotating body driving device as a driving device for a developer carrying member. In this image forming apparatus, a developing device main body, which is a support for a developing roller as a developer carrier, is configured to be able to move toward and away from a photoconductor as an image carrier. Further, a pair of drive input gears are provided at both ends of the support shaft of the developing roller. A pair of drive gears mesh with the pair of drive input gears. The developing roller is rotationally driven in a state where the developing device main body is displaced toward the photoconductor via the pair of drive input gears by a drive tangential force when the pair of drive gears are driven to rotate. Have been.
[0003]
In this type of image forming apparatus, if the contact pressure or the gap at the opposing portion between the photoreceptor and the developing roller is not constant, a difference occurs in the electric field strength at both ends of the developing region in the rotation axis direction. . When such a difference in electric field strength occurs, the transfer of the developer (toner) to the electrostatic latent image on the photoconductor becomes uneven in the development area, and the toner image formed on the photoconductor becomes Density gradients and edge image omissions occur.
Generally, in a development method called “contact development”, it is necessary to keep a contact pressure at a facing portion between a photoconductor and a developing roller constant. Further, in a developing method called “non-contact development”, it is necessary to keep a constant gap at a facing portion between the photoconductor and the developing roller.
In other words, the movement of the developer from the developing roller to the photoconductor is caused by the difference between the potential of the electrostatic latent image on the photoconductor with respect to the charged toner and the developing bias applied to the developing roller. It is performed by an electric field between the rollers. The photosensitive member and the developing roller are not in direct contact with each other even in the above-mentioned "contact development", and a developer or a toner is interposed therebetween, so that a gap exists in a developing region opposed to them. . When the gap between the developing regions becomes large, the electric field intensity between the photoconductor and the developing roller becomes weak, and it becomes difficult for the toner to transfer from the developing roller to the photoconductor.
If the electric field strength is strong, even if the developer (toner) layer on the developing roller and the photoconductor surface are separated as in the above-mentioned "non-contact development", the toner flies in the space of the development area and the photoconductor Transfer to the surface. However, in the "non-contact development", if the electric field intensity is not sufficient, the toner does not transfer to the photoconductor, and the toner image formed on the photoconductor suffers image omission.
For this reason, if the contact pressure or the gap at the opposing portion between the surface of the photoreceptor and the surface of the developing roller is not constant and is large at one end and small at the other end, the density gradient of the toner image and the end image Missing occurs. Therefore, in this type of image forming apparatus, the developing device main body, which is the support of the developing roller, needs to be opposed to the photosensitive member so that the contact pressure or the gap at the opposing portion between the photosensitive member and the developing roller is constant. is there.
[0004]
[Problems to be solved by the invention]
By the way, in this type of conventional image forming apparatus, generally, a developing device main body, which is a support for the developing roller, and a support for the photoreceptor, are often constituted by independent units. In such an image forming apparatus, a unitized developing device main body and a photoreceptor support are assembled to the image forming apparatus main body so that the surface of the developing roller and the surface of the photoreceptor are opposed to each other. .
[0005]
However, such a unitized developing device main body and the support of the photoreceptor have a certain degree of assembly accuracy error. Therefore, when the developing device main body and the photosensitive member support are assembled to the image forming device main body, the contact pressure or the gap at the opposing portion between the developing roller and the photosensitive member is not always constant.
For this reason, in this type of image forming apparatus, the density gradient and the edge image omission sometimes occur in the toner image due to the non-uniform contact pressure or gap at the opposing portion between the photoconductor and the developing roller. In order to solve such a problem, the contact pressure or the gap at the opposing portion between the photoreceptor and the developing roller may be adjusted so as to be constant. However, this adjustment requires a high skill. Was.
[0006]
The present invention has been made in view of the above problems. The purpose is to make it possible to easily and uniformly adjust the contact pressure or the gap at the facing portion between the rotating body and the facing member, for example, the contact pressure or the gap at the facing portion between the developing roller and the photoconductor. The object is to provide a body drive.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a rotating body driving device for rotatingly rotating a rotating body disposed to face a facing member, wherein a support of the rotating body is the facing member. A pair of drive gears, which are configured to be movable toward and away from, and mesh with a pair of drive input gears provided at both ends of a support shaft of the rotating body, and a drive tangent at the time of drive rotation of the pair of drive gears. In a rotating body driving device configured to rotationally drive the rotating body in a state where the support of the rotating body is displaced toward the facing member side through the pair of drive input gears by the force, A pair of drive gears are constituted by a pair of helical gears in which the torsion directions of the tooth traces are symmetric and the torsion angle is the same, and the drive shafts of the pair of helical gears are moved along the rotation center axis direction. Freely supporting the shaft, moving the drive shaft appropriately, For serial pair of drive input gear is characterized in that it has configured to adjust the engagement position of the pair of helical gears.
In this rotating body driving device, by driving the drive shafts of the pair of helical gears in the direction of the rotation center axis, the pair of drive input gears are respectively moved along the tooth trace direction of the pair of helical gears. Displaces in the opposite direction. Displacement of the pair of drive input gears in the opposite direction causes the support shaft of the rotating body provided with the drive input gears to swing. Due to the swing of the support shaft of the rotating body, the contact pressure or the gap at both ends of the facing portion between the facing member and the rotating body changes. Then, the drive shafts of the pair of helical gears are moved so that the contact pressure or the gap at both ends of the facing portion between the facing member and the rotating body becomes equal. Thereby, the contact pressure or the gap at the facing portion between the facing member and the rotating body is adjusted to be constant.
According to a second aspect of the present invention, in the rotating body driving device of the first aspect, the moving range of the drive shafts of the pair of helical gears is set to a range where the engagement of the pair of helical gears with the pair of drive input gears does not come off. The reference position at which the movement of the drive shaft is started is set to a position where the center of the tooth width of the pair of drive input gears coincides with the center of the tooth width of the pair of helical gears. It is.
According to a third aspect of the present invention, in the rotating body driving device of the first or second aspect, the drive shafts of the pair of helical gears are appropriately moved to adjust the meshing position of the pair of helical gears with the pair of drive input gears. An elastic member for biasing the drive shafts of the pair of helical gears toward one end, and a positioning member for positioning the drive shaft at a position shifted by a predetermined amount against the elasticity of the elastic member. And characterized in that:
According to a fourth aspect of the present invention, there is provided a driving device for rotationally driving a developer carrier opposed to an image carrier, wherein the developing device main body, which is a support for the developer carrier, includes the photosensitive member. Has a pair of drive gears that are configured to be movable toward and away from, and mesh with a pair of drive input gears provided at both ends of the support shaft of the developer carrying member, and when the pair of drive gears are driven to rotate. An image forming apparatus comprising: a driving device configured to rotationally drive the developer carrier in a state where the developing device main body is displaced toward the photoconductor side via the pair of driving input gears by a driving tangential force. In the apparatus, a rotating body driving device according to claim 1, 2, or 3 is used as the driving device.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the rotating body driving device of the present invention is applied to a driving device that rotationally drives a developing roller that is a developer carrier of a developing device in an image forming apparatus will be described.
FIG. 1 shows a color laser printer (hereinafter simply referred to as “printer”) 1 as the image forming apparatus. The printer 1 includes a photoconductor 11, a charging device 12, a writing device 13, a developing device 14, an intermediate transfer belt 15, a paper feeding device 16, a transfer device 17, a fixing device 18, a cleaning device 19, and the like.
[0009]
As the photoconductor 11 serving as an image carrier, a belt-shaped photoconductor having an organic photosensitive layer formed on a surface is used. Around the photoconductor 11, the charging device 12, the developing device 14, and the cleaning device 19 are provided.
The charging device 12 applies a high voltage to the photoconductor 11 to apply a uniform potential to the surface of the photoconductor.
The writing device 13 includes a laser (not shown), a polygon mirror 13A, an f / θ lens 13B, a reflection mirror 13C, and the like. A laser beam corresponding to each image signal of black (hereinafter abbreviated as B), cyan (hereinafter abbreviated as C), magenta (hereinafter abbreviated as M), and yellow (hereinafter abbreviated as Y) is emitted from the laser. Is done. The laser light is incident on the photoconductor 11 via the polygon mirror 13A, the f / θ lens 13B, and the reflection mirror 13C, and optical writing is performed. Thereby, an electrostatic latent image of each color is formed on the surface of the photoconductor 11.
[0010]
The developing device 14 includes four developing cartridges 21 in which toner of each color, which is charged by applying a charge having a polarity opposite to the potential applied by the charging device 12 to the photoreceptor 11, is individually stored. I have. Each of the developing cartridges 21 has the same configuration, and FIG. 2 shows one of the developing cartridges 21. Each developing cartridge 21 is provided with a developing roller 22 as shown in FIG. The toner of each color is electrostatically attracted to the electrostatic latent image on the surface of the photoconductor 11 via the developing roller 22 of each developing cartridge 21, and a toner image of each color is sequentially formed on the surface of the photoconductor 11.
[0011]
The intermediate transfer belt 15 is in contact with a part of the surface of the photoreceptor belt 11. The intermediate transfer belt 15 is applied with a charge having a polarity opposite to that of each color toner. As a result, the toner images of each color formed on the surface of the photoconductor 11 are sequentially superimposed and transferred onto the intermediate transfer belt 15, and four color images are formed on the intermediate transfer belt 15.
The color image formed on the intermediate transfer belt 15 is transferred by the transfer device 17 to the transfer paper conveyed by the conveyance roller from the paper supply device 16 by applying a charge having a polarity opposite to that of the toner. Transferred to transfer paper. Then, the transfer paper on which the color image has been transferred is discharged outside the printer main body after the toner is fused and fixed by the fixing device 18.
[0012]
Next, a driving device of the developing cartridge 21 of the developing device 14 will be described. This driving device is prepared in the same manner for each of the developing cartridges 21 containing the toners of B, C, M, and Y, respectively. As shown in FIG. 2, the driving device of the developing device 14 includes the contact / separation mechanism 3 as the driving device for moving the developing cartridge 21 toward and away from the photoconductor 11.
[0013]
As shown in FIGS. 2 and 3A, each developing cartridge 21 is always provided with an elastic force in a direction away from the photoconductor 11 by a compression spring 23 provided between the developing cartridge 21 and the housing 10 on the apparatus main body side. Have been. Thus, when the development is not normally performed, the developing cartridge 21 is retracted to a state in which the developing cartridge 21 abuts on the stopper 24 provided on the housing 10 on the apparatus main body side by the elastic force of the compression spring 23 at the rear. Each developing cartridge 21 is detachable from the housing 10 on the apparatus main body side.
The developing cartridge 21 incorporates a developing roller 22 for supplying a color toner to the photoconductor 11. The developing roller 22 is rotated by a drive motor 31.
[0014]
The contact / separation mechanism 3 as the above-mentioned driving device, when performing a developing operation of supplying each color toner to the photoconductor 11, causes the developing roller 22 of the developing cartridge 21 containing the color toner to abut on the photoconductor 11 or at a minute interval. And hold them apart (see the solid line in FIG. 4). Then, when the developing operation is not performed, the developing roller 22 is separated from the photoconductor 11 (see a chain line in FIG. 4).
The contact / separation mechanism 3 includes a drive motor 31 attached to the housing 10 on the apparatus main body side, and gears 32A to 32C that rotate by the driving force of the drive motor 31. Further, it has a clutch 32D for connecting and turning the rotational force of the gear 32C to the drive shaft 33, a drive gear 34 fixed to the drive shaft 33, and a pair of right and left driven gears 35 meshing with the drive gear 34. Further, it has a rotating shaft 38 on which the developing roller 22 is mounted coaxially with the driven gear 35, caps 36 provided at both ends of the rotating shaft 38, and a guide member 37 for guiding the movement of the cap 36. .
[0015]
The drive gear 34 is composed of a pair of drive gears 33 fixed to the left and right ends of the drive shaft 33. The drive shaft 33 is rotatably attached to the housing 10 of the apparatus main body via a bearing 10D.
The driven gear 35 is attached to both sides of the developing cartridge 21 and is movable with respect to the housing 10 on the apparatus main body side. The moving direction of the driven gear 35 is regulated by a guide member 37.
Further, as shown in FIG. 4, the cap 36 is formed of a substantially disk-shaped member having a predetermined radius and provided at both ends of a rotating shaft 38 coaxial with the driven gear 35 and the developing roller 22.
[0016]
On the other hand, as shown in FIG. 4, the guide member 37 has a shape having a narrowed portion 37A whose diameter is reduced toward the photoconductor 11. Then, when the cap 36 abuts on the narrow portion 37A of the guide member 37, the movement operation of the developing cartridge 21 is stopped. Accordingly, the approach operation is regulated so that the developing cartridge 21 and the developing roller 22 do not approach the photosensitive member 11 more than a predetermined distance. The positions of the developing cartridge 21 and the developing roller 22 when the cap 36 comes closest are the normal developing positions for the photoconductor 11.
[0017]
As described above, in the developing device 14, each developing cartridge is appropriately selected and moved, and the developing roller 22 of the developing cartridge 21 is brought into contact with the photosensitive member 11 or is maintained at a small interval by the contact / separation device 3. It is configured to be separated.
However, the developing device 14 and the support of the photoreceptor 11 have a certain degree of assembly accuracy error. Therefore, if the developing device 14 and the photoconductor 11 are simply assembled, the contact pressure or the gap at the opposing portion between the developing roller 22 and the photoconductor 11 is not always constant. For this reason, in this type of image forming apparatus, when the contact pressure or the gap at the opposing portion between the photoreceptor 11 and the developing roller 22 is not constant, there is a problem that a density gradient or an end image dropout occurs in the toner image. there were.
[0018]
This problem can be solved by using the driving device according to each embodiment described below. FIG. 5 schematically shows a configuration common to the driving devices according to the embodiments. Note that among components of the drive device according to the following embodiments, components having the same configuration and functions as those of the drive device illustrated in FIG. 5 are assigned to the components of the drive device. The same reference numerals are given to the reference numerals, and the description is omitted.
As shown in FIG. 5, this driving device is driven by a pair of driving input gears at both ends of a rotating shaft 38 which is a support shaft of the developing roller 22, similarly to the driving devices shown in FIGS. A gear 35 is provided. The driven gear 35 meshes with a drive gear 34 as a pair of drive gears provided on the drive shaft 33. The pair of drive gears 34 move the developing roller 22 in a state where the selected developing device 14 is displaced toward the photoconductor 11 via the pair of driven gears 38 by a drive tangential force at the time of driving rotation. Drive rotationally.
[0019]
Here, in the drive device according to each embodiment, the pair of drive gears 34 are formed of a pair of helical gears having mutually symmetrical tooth traces in the torsion direction and the same torsion angle. The drive shaft 33 of each drive gear 34 composed of the helical gear is supported so as to be movable along the rotation center axis direction. Further, in this drive device, the meshing position of each drive gear 34 with respect to the pair of driven gears 35 can be adjusted by appropriately moving the drive shafts 33 of the pair of drive gears 34 by drive shaft movement adjusting means described later. It has become.
[0020]
For example, in FIG. 5, it is assumed that the drive shafts 33 of the pair of drive gears 34 have been moved to the left along the rotation center axis direction. As a result, as shown in FIG. 5A, the pair of driven gears 35 are displaced in opposite directions along the tooth trace direction of the drive gear 34 including the pair of helical gears. That is, the leftmost driven gear 35 is displaced downward, and the rightmost driven gear 35 is displaced upward. Due to the displacement of the pair of driven gears 35 in the opposite direction, the rotating shaft 38 of the developing roller 22 provided with the driven gears 35 swings counterclockwise. Due to the counterclockwise swing of the rotating shaft 38 of the developing roller 22, the contact pressure or the gap at both ends of the opposing portion between the photoconductor 11 and the developing roller 22 changes.
Contrary to this, in FIG. 5, it is assumed that the drive shafts 33 of the pair of drive gears 34 have been moved rightward along the rotation center axis direction. As a result, as shown in FIG. 5C, the pair of driven gears 35 move upward along the tooth trace direction of the drive gear 34 composed of a pair of helical gears, and the driven gear 35 on the left end rises upward and the right end Of the driven gear 35 is displaced downward. The displacement of the pair of driven gears 35 in the opposite direction causes the rotation shaft 38 of the developing roller 22 provided with the driven gears 35 to swing clockwise. Due to the clockwise swing of the rotation shaft 38 of the developing roller 22, the contact pressure or the gap at both ends of the opposing portion between the photoconductor 11 and the developing roller 22 changes.
Here, the state shown in FIG. 5B shows a reference position where the movement of the drive shaft 33 starts. This reference position is set at a position where the center of the tooth width of the pair of driven gears 35 and the center of the tooth width of the pair of drive gears 34 match. Thereby, the drive shaft 33 can be moved in the left-right direction about the reference position, and the rotation shaft 38 of the developing roller 22 can be swung substantially equally in the clockwise direction and the counterclockwise direction. Become. Therefore, even when the developing roller 22 is inclined with respect to the photosensitive member 11 in any direction when the developing device 14 and the photosensitive member 11 are assembled, the inclination can be corrected relatively easily in a short time. . The range of movement of the drive shafts 33 of the pair of drive gears 34 is set to a range where the engagement of each drive gear 34 with the pair of driven gears 35 does not come off. This prevents the driven gear 35 from being disengaged from the drive gear 34 due to the movement of the drive shaft 33.
As described above, in this drive device, the drive shaft 33 of the drive gear 34 including the pair of helical gears can be moved to swing the rotation shaft 38 of the developing roller 22. This makes it possible to adjust the contact pressure or the gap at the opposing portion between the photoconductor 11 and the developing roller 22 to a constant state.
[0021]
(Embodiment 1)
The driving device according to the first embodiment has the following features in addition to the configuration of the driving device in FIG. FIG. 6 shows an example of the drive shaft movement adjusting means of the drive device according to the first embodiment. This drive shaft movement adjusting means has a coil spring 103 as an elastic member for biasing the drive shaft 33 of the drive gear 34 composed of a pair of helical gears toward one end. The coil spring 103 elastically moves the retaining ring 104 between a retaining ring 104 attached to one end of the driving shaft 33 and a bearing of the driving shaft 33 disposed on the side plate 105 of the image forming apparatus main body. It is arranged so as to press. When the retaining ring 104 is pressed by the coil spring 103, a biasing force for biasing the drive shaft 33 to the left in FIG.
The drive shaft movement adjusting means adjusts the position of the drive shaft 33 at a position where the drive shaft 33 is moved to the right by a predetermined amount in FIG. 6 against the elasticity of the coil spring 103. It has latches 100 and 101. The adjustment latches 100 and 101 include a fixed member (100) fixed to another side plate 106 of the main body of the image forming apparatus and a movable member (100) rotatably disposed on the drive shaft 33 so as to face the fixed member. 101). As shown in FIG. 7, the fixing member has a point-symmetric groove 100b formed on the inclined surface 100a. On the other hand, the movable member is provided with a projection 101a that fits into the groove 100b of the fixed member. By changing the fitting position between the protrusion of the movable member and the groove of the fixed member, the position of the movable member with respect to the fixed member is gradually changed. Thus, the drive shaft 33 moves stepwise as shown in FIGS. 6A, 6B and 6C, and the position of the drive gear 34 is displaced. Here, the position of the drive gear 34 in FIG. 6A corresponds to the position of the drive gear 34 in FIG. The position of the drive gear 34 in FIG. 6B corresponds to the position of the drive gear 34 in FIG. Further, the position of the drive gear 34 in FIG. 6C corresponds to the position of the drive gear 34 in FIG. As described above, in this drive device, the position of the drive shaft 33 can be adjusted and moved stepwise by the rotation of the adjustment latch 101.
[0022]
(Embodiment 2)
The driving device according to the second embodiment has the following features in addition to the configuration of the driving device in FIG. FIG. 8 shows an example of the drive shaft movement adjusting means of the drive device according to the second embodiment. This drive shaft movement adjusting means uses adjustment screws 110 and 111 as a positioning member for positioning the drive shaft 33. These adjusting screws 110 and 111 are fixed screws (111) fixed to the other side plate 106 of the image forming apparatus main body, and movable screws (110) that are screwed together with the fixing screws and are rotatably disposed on the drive shaft 33. ). By changing the screwing position between the movable screw and the fixed screw, the position of the movable screw with respect to the fixed screw is displaced. Accordingly, the drive shaft 33 sequentially moves as shown in FIGS. 8A, 8B, and 8C, and the position of the drive gear 34 is displaced. Here, the position of the drive gear 34 in FIG. 8A corresponds to the position of the drive gear 34 in FIG. The position of the drive gear 34 in FIG. 8B corresponds to the position of the drive gear 34 in FIG. Further, the position of the drive gear 34 in FIG. 8C corresponds to the position of the drive gear 34 in FIG. As described above, in this drive device, the position of the drive shaft 33 can be arbitrarily adjusted by the rotation of the adjustment screws 110 and 111.
[0023]
(Embodiment 3)
The rotating body driving device according to the third embodiment has the following features in addition to the configuration of the driving device in FIG. FIG. 9 shows an example of the drive shaft movement adjusting means of the drive device according to the third embodiment. This drive shaft movement adjusting means uses a slider 120 having a stepped step surface as shown in FIG. 10 as a positioning member for positioning the drive shaft 33. As shown in FIG. 9, the slider 120 has a drive shaft between a side plate of the image forming apparatus main body and a retaining ring attached to an end of a drive shaft 33 movably supported by the side plate. It is mounted so as to straddle 33. By changing the mounting position of the slider 120 on the drive shaft 33, the position of the step surface of the slider 120 with respect to the retaining ring is displaced. Thus, the drive shaft 33 moves stepwise as shown in FIGS. 9A, 9B, and 9C, and the position of the drive gear 34 is displaced. Here, the position of the drive gear 34 in FIG. 9A corresponds to the position of the drive gear 34 in FIG. The position of the drive gear 34 in FIG. 9B corresponds to the position of the drive gear 34 in FIG. Further, the position of the drive gear 34 in FIG. 9C corresponds to the position of the drive gear 34 in FIG. As described above, in this drive device, the position of the drive shaft 33 can be adjusted and moved stepwise by changing the mounting position of the slider 120.
[0024]
As described above, in the driving device according to the first embodiment, by changing the fitting position between the protrusion of the movable member of the adjustment latch 101 of the drive shaft movement adjusting means and the groove of the fixed member, the movable member with respect to the fixed member is changed. Is displaced stepwise. Thus, the drive shaft 33 moves stepwise as shown in FIGS. 6A, 6B and 6C, and the position of the drive gear 34 is displaced. Then, by the movement of the drive shaft 33, the rotation shaft 38 of the developing roller 22 can be swung stepwise, and the contact pressure or the gap at the opposing portion between the photoconductor 11 and the developing roller 22 is kept constant. Can be adjusted. As a result, it is possible to prevent the density gradient in the longitudinal direction of the toner image formed on the photoconductor 11 and the omission of the image end.
In the drive device according to the second embodiment, the position of the movable screw relative to the fixed screw is displaced by changing the screwing position between the movable screw of the adjustment screw 110, 111 of the drive shaft movement adjusting means and the fixed screw. . Accordingly, the drive shaft 33 sequentially moves as shown in FIGS. 8A, 8B, and 8C, and the position of the drive gear 34 is displaced. By the movement of the drive shaft 33, the rotation shaft 38 of the developing roller 22 can be oscillated arbitrarily, and the contact pressure or the gap at the opposing portion between the photoconductor 11 and the developing roller 22 is kept constant. Be able to adjust.
In the driving device according to the third embodiment, the position of the step surface of the slider 120 with respect to the retaining ring is displaced by changing the mounting position of the driving shaft movement adjusting means on the driving shaft 33 of the slider 120. Thus, the drive shaft 33 moves stepwise as shown in FIGS. 9A, 9B, and 9C, and the position of the drive gear 34 is displaced. Then, by the movement of the drive shaft 33, the rotation shaft 38 of the developing roller 22 can be swung stepwise, and the contact pressure or the gap at the opposing portion between the photoconductor 11 and the developing roller 22 is kept constant. Can be adjusted.
Further, in the image forming apparatus using the driving device according to each of the above embodiments, the contact pressure or the gap at the portion where the developing roller 22 and the photoconductor 11 face each other can be adjusted to be constant. As a result, it is possible to easily eliminate the density gradient of the toner image in the longitudinal direction of the toner image formed on the photoconductor 11 and the omission of an image at an end portion, thereby enabling high-quality image formation. Further, in this image forming apparatus, it is possible to readjust the contact pressure or the gap at the portion facing the photoconductor 11. Further, it is possible to easily adjust the contact pressure or the gap at the portion facing the photoconductor 11 at the time of manufacturing and on the user side.
[0025]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the contact pressure or gap in the opposing part of a rotating body and an opposing member, for example, the contact pressure or gap in the opposing part of a developing roller and a photoreceptor, can be adjusted easily and easily. Has an effect.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an image forming apparatus using a driving device to which the present invention is applied.
FIG. 2 is a schematic configuration diagram showing a contact / separation mechanism of a developing device in the image forming apparatus.
FIG. 3A is an explanatory view showing a state where a developing cartridge and a developing roller of the developing device are separated from each other;
FIG. 3B is an explanatory diagram illustrating a state in which the developing cartridge and the developing roller are in contact with or in proximity to the photoconductor.
FIG. 4 is an explanatory view showing a guide member and the like used for an abutting or approaching operation of the developing roller to a photoconductor.
FIGS. 5A, 5B, and 5C are schematic diagrams schematically showing a common configuration of a driving device according to each embodiment of the present invention.
FIGS. 6A, 6B, and 6C are schematic configuration diagrams illustrating an operation mode of an adjustment latch of a drive shaft movement adjustment unit of the drive device according to the first embodiment of the present invention.
FIG. 7 is a perspective view showing an adjustment latch of the drive shaft movement adjusting means of the drive device according to the first embodiment.
FIG. 8 is a schematic configuration diagram illustrating an operation mode of an adjustment screw of a drive shaft movement adjustment unit of the drive device according to the second embodiment of the present invention.
FIG. 9 is a schematic configuration diagram showing an operation mode of a slider 120 of a drive shaft movement adjusting unit of the drive device according to the eighth embodiment of the present invention.
FIG. 10 is a perspective view showing a slider 120 of a drive shaft movement adjusting means of a drive device according to an eighth embodiment of the present invention.
[Explanation of symbols]
1 Printer
3 Contact / separation mechanism
10 Case
11 Photoconductor
12 Charging device
13 Writing device
14 Developing device
15 Intermediate transfer device
16 Paper feeder
17 Transfer device
18 Fixing device
19 Cleaning device
21 Developing cartridge
22 Developing roller
23 Compression spring
24 Stopper
32D clutch
33 Drive shaft
34 drive gear
35 driven gear
36 caps
37 Guide member
38 Rotation axis
100,101 Adjustment latch
100a Slope of adjustment latch
100b Adjustment latch groove
101a Adjustment latch protrusion
103 Coil spring
104 retaining ring
105,106 side plate
110,111 adjustment screw
120 slider

Claims (4)

A rotating body driving device for rotationally driving a rotating body arranged to face the facing member,
The support of the rotating body is configured to be movable toward and away from the opposing member,
It has a pair of drive gears that mesh with a pair of drive input gears provided at both ends of the support shaft of the rotating body,
The rotating body is rotationally driven in a state where the support of the rotating body is displaced toward the opposing member via the pair of drive input gears by a driving tangential force at the time of driving rotation of the pair of driving gears. In the rotating body driving device configured as described above,
The pair of drive gears are constituted by a pair of helical gears in which the torsion directions of the tooth traces are symmetric and the torsion angle is the same,
The drive shafts of the pair of helical gears are movably supported along the rotation center axis direction,
A rotating body drive device wherein the drive shaft is appropriately moved to adjust the meshing position of the pair of helical gears with the pair of drive input gears. The rotating body driving device according to claim 1,
The range of movement of the drive shafts of the pair of helical gears is set to a range where the engagement of the pair of helical gears with the pair of drive input gears does not come off,
A reference position for starting the movement of the drive shaft is set at a position where the center of the tooth width of the pair of drive input gears and the center of the tooth width of the pair of helical gears coincide with each other. apparatus. The rotating body driving device according to claim 1 or 2,
Drive shaft movement adjusting means for adjusting the meshing position of the pair of helical gears with respect to the pair of drive input gears by appropriately moving the drive shafts of the pair of helical gears,
An elastic member that biases the drive shafts of the pair of helical gears toward one end,
And a positioning member for positioning the drive shaft at a position shifted by a predetermined amount against the elasticity of the elastic member. A drive device for rotationally driving a developer carrier that is disposed to face the image carrier,
A developing device main body, which is a support for the developer carrying member, is configured to be movable toward and away from the photoconductor,
Having a pair of drive gears that mesh with a pair of drive input gears provided at both ends of the support shaft of the developer carrier,
The developer carrier is rotationally driven in a state where the developing device main body is displaced toward the photoconductor side via the pair of drive input gears by a drive tangential force at the time of drive rotation of the pair of drive gears. An image forming apparatus having a driving device configured as
An image forming apparatus, comprising: the rotating device driving device according to claim 1, 2 or 3 as the driving device.

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