JP2000147978A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily drive a fixing roller by satisfactorily meshing a drive gear on the fixing roller side with a main body gear on a main body side regardless of the deviation of a unit device which can be attached to/ detached from the main body in a horizontal direction, in the case of integrally supporting a transfer device and the fixing roller and attaching the unit device to the main body. SOLUTION: This device is provided with an inter-axial distance holding member 102 turnably attached pivotally to the shaft 34 of the main body gear 33 and having a round hole 102a. A positioning pin 28a on the transfer unit 14 side of the unit device 28 is inserted through a fixed round hole 101a on a main body internal wall 101, while the member 102 is turned according to the deviation of the shaft 31 of a heat roller 23a in the horizontal direction, and the shaft 31 is inserted through the round hole 102a, so that the unit device 28 is attached to the main body 100. Thus, an axle-to-axle distance between the main body gear 33 and the driving gear 32 is always kept constant and both gears are excellently meshed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus and the like, and more particularly to an image forming apparatus having a unit for integrally supporting each device constituting a sheet paper conveying path from a transfer device to a fixing roller. The present invention relates to the adjustment of a positional shift when mounting on a device main body.

[0002]

2. Description of the Related Art In an electrophotographic apparatus or the like, a sheet paper conveyance path from a transfer device facing a photoreceptor and transferring a toner image on the photoreceptor to sheet paper from a fixing roller for heating and pressing and fixing the toner image on the sheet paper. In an image forming apparatus having a unit device in which the above device is unitized and can be integrally attached to and detached from the device main body, this unit device is usually inserted and removed from the front side of the device main body.

When the unit is mounted on the main body at the time of assembling / manufacturing or after removing a paper jam, a positioning reference is provided on the side of the transfer device which requires high positional accuracy because it is close to the photosensitive member. That is, conventionally, as shown in FIG. 8, a round hole 2 is formed on the side of the main body inner wall 1 facing the transfer device, while a long hole 3 is formed on the side facing the fixing roller. The pin 6 provided on the fixing device side is inserted into the round hole 2 to regulate the mounting position of the unit 4 with respect to the apparatus main body, and the pin 7 provided on the fixing roller side of the unit device 4 is inserted into the elongated hole 7 to thereby form the unit device. 4 was adjusted in the horizontal direction.

[0004]

Conventionally, when a unit device that integrally supports a transfer device and a fixing roller is mounted on a main body, a positioning reference is provided on the transfer device side, and adjustment of horizontal displacement of the unit device is performed by fixing. It was going on the roller side.
On the other hand, the driving of the fixing roller is performed by attaching the unit device to the apparatus main body so that the driving gear provided on the fixing roller side meshes with the main body gear on the apparatus main body side, and the driving by the main body side driving source is moved to the fixing roller side. I was communicating and going.

For this reason, when the unit device is mounted on the main body device, if the horizontal displacement of the unit device on the fixing roller side is large, the deviation between the axes of the drive gear and the main body gear becomes large, resulting in insufficient engagement between the two gears. Also, there has been a problem that the gear is not driven due to excessive meshing. Specifically, in the case of a gear having 25 teeth in the module 1, the dimension between the shafts of the drive gear and the main body gear is required to be in the range of (Expression 1). In addition, if it is smaller than (Equation 1), the gears are in contact with the tooth bottom.

[0006]

(Equation 1) In view of the above, the present invention has been made to solve the above-described problem, and despite the fact that a positioning reference when the unit device is mounted on the apparatus main body is provided on the transfer device side, the drive gear on the fixing roller side and the main body gear on the main body device side are provided. It is an object of the present invention to provide an image forming apparatus capable of always maintaining a constant distance between shafts and transmitting the drive from the drive source of the main body device to the fixing roller in a satisfactory manner.

[0007]

According to the present invention, as a first means for solving the above-mentioned problems, a transfer means facing an image carrier, and a developer transferred from the image carrier by the transfer means. A pair of fixing rollers for holding the image-receiving member having an image therebetween by heating and pressurizing, a driving gear pivotally mounted on the fixing roller and rotating the fixing roller, and a conveying direction of the image-receiving member relative to the apparatus main body; A unit that can be pulled out in a direction perpendicular to the unit and that integrally supports a transfer path of the transfer target body from at least the transfer unit to the fixing roller; and a unit that is provided on the apparatus main body side and connects the unit to the apparatus main body. When the main body gear meshes with the drive gear at the time of mounting, and when the unit is mounted on the main body, the axis between the main body gear and the drive gear always stays irrespective of the positional shift of the unit at the fixing roller side. Is intended to provide a holding means for holding constant The present invention is a second means for solving the above problems,
A transfer unit facing the image carrier, a pair of fixing rollers for sandwiching a transfer target having a developer image transferred from the image carrier by the transfer unit, and applying heat and pressure to the transfer unit; A drive gear for axially rotating the fixing roller,
A unit that can be pulled out of the apparatus main body in a direction orthogonal to the conveyance direction of the transfer target and integrally supports at least a transfer path of the transfer target from the transfer unit to the fixing roller; A main body gear provided on the side of the unit and meshing with the drive gear when the unit is mounted on the apparatus main body; a positioning pin provided on a transfer unit side of the unit; and an adjustment pin provided on the fixing roller side of the unit. Fixed support means provided on the device main body side for supporting the positioning pin in a detachable manner, and always provided between the axes of the main body gear and the drive gear irrespective of a positional shift of the unit provided on the device main body side. Movable support means for supporting the adjustment pin so as to be able to be inserted and removed so as to keep the adjustment pin constant.

According to a third aspect of the present invention, there is provided a transfer unit facing an image carrier, and a transfer device having a developer image transferred from the image carrier by the transfer unit. A pair of fixing rollers for holding the body under heat and pressure, and a driving gear for rotating the fixing roller by being attached to the fixing roller, and a direction orthogonal to a conveying direction of the transfer object with respect to the apparatus main body. A unit that can be pulled out and integrally supports a transfer path of the transfer target body from at least the transfer unit to the fixing roller; and a drive gear that is provided on the apparatus main body side and mounts the unit on the apparatus main body when the unit is mounted on the apparatus main body. A positioning gear provided on the transfer unit side of the unit, an adjustment pin provided on the fixing roller side of the unit, and the position provided on the apparatus body side. Fixed support means for detachably supporting a female pin, and movable support means having a round hole rotatable around the axis of the main body gear on the device main body side and supporting the adjustment pin in a removable manner. Are provided.

According to the present invention, the present invention provides a fixing device in which the holding device shifts the shaft between the main body gear on the main body device and the drive gear on the unit device side, despite the horizontal displacement of the unit device on the fixing roller side. By always keeping the gear constant, the gears are properly meshed with each other and the fixing roller is reliably rotated to improve the reliability of the apparatus.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 shows image forming means 2
1 shows a main body 100 of an image forming apparatus including an automatic duplexer 30, a paper feed unit 40, a large capacity cassette device 50, and the like. A drum-shaped photoconductor 1 is provided at a substantially central portion in the main body 100.
The charging device 11, the exposure unit 12 a of the exposure device 12, the developing device 13, and the transfer device 14
a, a transfer unit 14 having a charge applying roller 14b,
A cleaning device 16 and a static eliminator 17 are provided to constitute the image forming means 20.

On the right side of the main body 100, a manual feed unit 1 is provided.
8 and a large-capacity cassette device 50 are attached, and the paper supply unit 40 is provided with first to third paper supply cassette devices 40a to 40c for storing sheet paper P of an arbitrary size. An automatic double-sided device 30 is disposed below the photoconductor 10 of the main body 100. A transport path 60 is formed between each of the sheet cassette devices 40 a to 40 c for supplying the sheet paper P and the transfer unit 14. Further, inside the main body 100, a conveyance belt 22 and a conveyance belt 2 that convey the sheet paper P on which the toner image has been transferred from the photoconductor 10 by the transfer unit 14 via the registration roller 21.
2, a pair of fixing roller devices 23 including a heat roller 23a and a press roller 23b for heating and fixing the sheet P conveyed by the sheet feeding device 2. The sheet P after fixing is guided to a sheet discharge tray 26 via a sheet discharge roller 24. , A main transport path 27 is formed.

Here, the transfer unit 14, the conveyor belt 2
2. The fixing roller device 23 is all integrated into one unit,
It is configured as a unit device 28 represented by cross hatching in FIG. The unit device 28 is fitted into a rail (not shown) laid in the main body 100 in the front-rear direction, and is opened and closed from the front surface side of the main body 100 by opening a front door (not shown) of the main body 100. It is free. Transfer unit 14 on the rear side of unit device 28
On the side, a fixed round hole 101a formed in the main body inner wall 101
Is provided with a positioning pin 28a to be inserted into and removed from the device.

On the other hand, at the rear end of the shaft 31 of the heat roller 23a, a drive gear 3 having 25 teeth in the module 1 is provided.
2 is attached, and the module 1 driven by a driving source (not shown) on the main body side when mounted on the main body 100 has 25 teeth.
The heat roller 23a is driven in mesh with the main body gear 33. A shaft holding member 102 having a round hole 102a is rotatably mounted on a shaft 34 of the main body gear 33 so as to be rotatable. The inter-axis holding member 102 is driven by the shaft 3 by its own weight.
± from the reference position where 4 and the round hole 102a are perpendicular to each other.
It is configured to rotate 5 °. Further, the shaft holding member 10
The distance from the center of the second shaft 34 to the center of the round hole 102a is set to be (Equation 1).
The body gear 33 and the drive gear 3 are inserted through the shaft 31 of the heat roller 23a also serving as a position adjustment pin.
2 is always (Equation 1), and the body gear 3
3 and the drive gear 32 are meshed well.

The paper discharge rollers 24 of the main transport path 27
Upstream, a gate for sorting whether the sheet paper P after fixing is discharged as it is or is conveyed again to the photoconductor 10 side by the automatic double-sided device 30 for double-sided copying.
G is provided.

Next, the operation will be described. When the unit device 28 is mounted on the main body 100 at the time of assembling the main body 100, the unit device 28 is fitted into a rail (not shown) from the front surface and slid into the main body.
The positioning pin 28a on the side is inserted into the fixed round hole 101a to determine the mounting position of the unit device 14 with respect to the photoreceptor 10. On the other hand, on the fixing roller device 23 side of the unit device 28, the inter-axis holding member 102 is rotated by a necessary amount in accordance with the horizontal displacement of the shaft 31, and the shaft 31 is inserted into the round hole 102a of the inter-axis holding member 102. Insert. As a result, although the shaft 31 is displaced in the horizontal direction, the body gear 33
The distance between the shaft 34 of the drive gear 32 and the shaft 31 of the drive gear 32 is always kept constant.
And mesh well.

The position of the round hole 102a is raised by rotating the inter-axis holding member 102.
The influence of the rise of the sheet on the unit device 28 is extremely small.
Even if the center hole 8 is shifted by 1 mm in the horizontal direction with respect to the main body 100, the vertical movement of the round hole 102a due to the rotation of the inter-axis holding member 102 is extremely small as 0.02 mm as shown in FIG. There is no risk of adversely affecting the transport of P.

As described above, the unit device 28 is
After the photoreceptor 10 is mounted, the photoreceptor 10 is sequentially charged, exposed and developed by the image forming means 20 in accordance with the rotation of the photoreceptor 10 according to its rotation to form a toner image on the surface thereof.
The transfer unit 14 is reached. In synchronization with this, sheet paper P is supplied to the transfer unit 40 from the paper feed unit 40 or the large-capacity cassette device 50, and the sheet paper P is transferred from the photoconductor 10 after the toner image on the photoconductor 10 is transferred. The toner image is peeled, conveyed to the fixing roller device 23 by the transfer belt 14a and the conveyance belt 22, and inserted between the fixing roller devices 23 to fix the toner image. Thereafter, the sheet paper P is discharged to the paper discharge tray 26 by the paper discharge roller 24, or sorted to the automatic double-sided device 30 and re-conveyed to the photoconductor 10 for backside copying. After the transfer, the photosensitive member 1
0 can be copied next through the cleaning device 16 and the neutralization device 17.

In the meantime, the sheet P
When a paper jam occurs, the front door (not shown) of the main body 100 is opened, and the positioning pin 28a and the shaft 31 are pulled out from the round holes 101a and 102a, respectively, so that the main gear 33 and the drive gear 32 are engaged. After the release, the unit device 28 is taken out of the main body 100 to remove a paper jam.
Thereafter, the unit device 28 is mounted in the main body 100,
As in the above-described assembling, the positioning pin 28a is fixed to the round hole 1.
On the other hand, on the side of the fixing roller device 23, the inter-axis holding member 102 is rotated by a required amount in accordance with the horizontal displacement of the shaft 31 to rotate the shaft 31 into the round hole 102a of the inter-axis holding member 102. And the unit device 28 is attached to the main body 100, and the paper jam removing operation is completed.

With such a configuration, when the unit device 28 is mounted on the main body 100, even if the shaft 31 is displaced in the horizontal direction, the inter-axis holding member 102 is rotated in accordance with the displacement and is rotated by the round hole 102a. By supporting the shaft 31, the distance between the shaft 34 of the main gear 33 and the shaft 31 of the drive gear 32 can always be kept constant. Therefore, when the unit device 28 is mounted on the main body 100, even if the horizontal displacement of the unit device 28 is adjusted on the side of the fixing roller device 23 with the transfer unit 14 side close to the photoreceptor 10 as a positioning reference, the main body gear 33 Between the shaft 34 of the drive gear 32 and the shaft 31 of the drive gear 32 can be kept constant, and a good mesh between the main gear 33 and the drive gear 32 can be obtained without damaging the photoconductor 10. In addition, the vertical fluctuation of the round hole 102a due to the rotation of the inter-axis holding member 102 is extremely small, and does not adversely affect the conveyance of the sheet paper P by the unit device 28. Further, the shaft 31 of the heat roller 23a is
Even if a torque is generated in a direction in which the two gears 33 and 32 are separated by the rotation of the main body gear 33 and the driving gear 32 because the support is made by the support 02a, the shafts of the two gears 33 and 32 are reliably kept constant without being separated. Thus, both gears 33 and 32 can reliably maintain good meshing.

It should be noted that the present invention is not limited to the above-described embodiment, and can be changed without departing from the spirit of the present invention. For example, the structure of the unit is arbitrary and the transfer device and the transport belt are integrated. The transfer device may be a transfer roller or a transfer charger. Further, when the unit is supported by the inter-shaft holding member, the structure is arbitrary as long as the inter-shaft between the main body side gear and the drive gear is held constant, for example, as in the modification shown in FIG. In addition, while the adjustment pin 38 is provided in the unit device 36, the shaft 4 of the main body side gear 41 is
2 and the shaft 37 of the drive gear 44 on the heat roller 43 side
A round hole 10 on the extension of the straight line connecting the position 103b corresponding to
3a may be formed to support the adjustment pin 38 so that it can be inserted and removed. Furthermore, the rotation range of the inter-axis holding member is not limited as long as the horizontal displacement of the unit caused by a manufacturing error or the like can be adjusted.

[0021]

As described above, according to the present invention, when the unit device is mounted on the apparatus main body, the positioning of the unit device is performed with reference to the transfer device side close to the image carrier so as not to damage the image carrier. By doing so, even if the fixing roller side of the unit device is displaced in the horizontal direction, the holding means can always keep the distance between the axes of the main body gear and the drive gear constant.
The main body gear and the driving gear are always in good mesh with each other, and the fixing roller can be satisfactorily rotated by the main body driving source, thereby improving the reliability of the apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a unit device according to the embodiment of the present invention.

FIG. 3 is a schematic perspective view showing an inter-axis holding member according to the embodiment of the present invention.

FIG. 4 is a schematic sectional view showing an inter-axis holding member when the unit device according to the embodiment of the present invention is mounted.

FIG. 5 is a schematic side view showing an inter-axis holding member when the unit device according to the embodiment of the present invention is mounted.

FIG. 6 is a schematic explanatory view showing movement of the unit device according to the embodiment of the present invention in the vertical direction.

FIG. 7 is a schematic perspective view showing an inter-axis holding member according to another modification of the present invention.

FIG. 8 is a schematic perspective view showing a unit device of a conventional device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 photoconductor 14 a transfer belt 14 b charge applying roller 14 transfer unit 20 image forming unit 22 transport belt 23 fixing roller device 23 a heat roller 23 b press roller 28 unit device 28 a positioning pin 31 shaft Reference numeral 32: drive gear 33: body gear 34: shaft 100: body 101: body inner wall 101a: fixed round hole 102: inter-axis holding member 102a: round hole

Claims (5)

[Claims] A transfer unit opposed to the image carrier, and a pair of fixing rollers for sandwiching a transfer target having a developer image transferred from the image carrier by the transfer unit and heating and fixing the transfer target; A drive gear that is axially attached to the fixing roller and rotates the fixing roller; and a drive gear that can be pulled out of the apparatus main body in a direction orthogonal to a transport direction of the transfer target body and that extends from at least the transfer unit to the fixing roller. A unit that integrally supports the transfer path of the transferred object; a body gear that is provided on the apparatus main body side and meshes with the drive gear when the unit is mounted on the apparatus main body; An image forming apparatus comprising: a holding unit that always keeps a constant distance between the axes of the main body gear and the drive gear regardless of a positional shift of the unit on the fixing roller side when the image forming apparatus is mounted. Location. 2. A transfer unit facing the image carrier, and a pair of fixing rollers for sandwiching a transfer target having a developer image transferred from the image carrier by the transfer unit and heating and pressing the transfer member. A drive gear that is axially attached to the fixing roller and rotates the fixing roller; and a drive gear that can be pulled out of the apparatus main body in a direction orthogonal to a transport direction of the transfer target body and that extends from at least the transfer unit to the fixing roller. A unit integrally supporting a transfer path of the transfer target body, a main body gear provided on the apparatus main body side and meshing with the drive gear when the unit is mounted on the apparatus main body, and a transfer unit side of the unit. A positioning pin provided, an adjustment pin provided on the fixing roller side of the unit, a fixed support means provided on the apparatus main body side and supporting the positioning pin in a detachable manner; Movable support means provided on the main body of the apparatus for detachably supporting the adjustment pin so as to always keep a constant distance between the axes of the main body gear and the drive gear regardless of the position of the unit. An image forming apparatus comprising: 3. A transfer unit facing the image carrier, and a pair of fixing rollers for sandwiching a transfer member having a developer image transferred from the image carrier by the transfer unit and heating and fixing the transfer member. A drive gear that is axially attached to the fixing roller and rotates the fixing roller; and a drive gear that can be pulled out of the apparatus main body in a direction orthogonal to a transport direction of the transfer target body and that extends from at least the transfer unit to the fixing roller. A unit integrally supporting a transfer path of the transfer target body, a main body gear provided on the apparatus main body side and meshing with the drive gear when the unit is mounted on the apparatus main body, and a transfer unit side of the unit. A positioning pin provided, an adjustment pin provided on the fixing roller side of the unit, a fixed support means provided on the apparatus main body side and supporting the positioning pin in a detachable manner; Serial device image forming apparatus characterized by comprising a movable support means having said the rotatable shaft of the body gear fulcrum round hole for removably supporting said adjustment pin at the body side. 4. The image forming apparatus according to claim 3, wherein the adjustment pin is coaxial with the drive gear. 5. The movable support means is rotated by ± 5 ° about the axis of the main body gear from a reference position where the axis of the main body gear and the round hole are perpendicular to each other. Item 5. The image forming apparatus according to any one of Items 4.