JP2012181463A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable accurate rocking of a fixing unit by suppressing the deformation of a rocking plate.SOLUTION: An image forming device has a rocking mechanism for rocking a fixing unit in a rocking direction orthogonal to a conveyance direction of a sheet. The rocking mechanism comprises: a rocking plate disposed below the fixing unit; a connection member for connecting the fixing unit and the rocking plate so that the relative positional relation with respect to the rocking direction is not deviated; a base disposed below the rocking plate; a support member for the fixing unit for supporting the fixing unit with a predetermined space between the fixing unit and the rocking plate in a state where the relative positional relation with respect to the rocking direction between the base and the fixing unit can be freely changed; and a rocking part for rocking the rocking plate to the base. The rocking part is equipped with a freely rotatable eccentric cam and a pair of rollers for rocking attached to the rocking plate so as to be contacted with the eccentric cam in the rocking direction. When the rollers for rocking are moved in the rocking direction by the rotation of the eccentric cam, the rocking plate is rocked in conjunction with the movement.

Description

  The present invention relates to an image forming apparatus.

2. Description of the Related Art Conventionally, an image forming apparatus that forms an image on a recording medium by transferring the toner image to a recording medium is equipped with a fixing unit for fixing the toner image on the recording medium. In such an image forming apparatus, when the recording medium passes through the same unit every time it passes through the fixing unit, the end of the recording medium deteriorates the roller and belt end of the fixing unit. For this reason, conventionally, the recording medium is prevented from passing through the same place each time by swinging the stage on which the fixing unit is placed in a direction (swinging direction) orthogonal to the transport direction at a predetermined timing. Deterioration of the belt end is prevented (for example, see Patent Document 1).
Hereinafter, an example of a swing mechanism for swinging the fixing unit will be described with reference to FIG. As shown in FIG. 4, the swing mechanism 100 includes a base 101 fixed inside the image forming apparatus, a pair of support rollers 102 that are rotatably provided to the base 101, and a pair of support rollers. 102 and a swing plate 103 on which the fixing unit 200 is placed.
The base 101 includes a first protrusion 104 that extends downward. An eccentric cam 105 is rotatably attached to the first protrusion 104. On the other hand, the swing plate 103 includes a pair of second protrusions 106 extending downward. In addition, a pair of rocking rollers 107 that sandwich the eccentric cam 105 in the rocking direction are rotatably attached to the second protrusion 106. The pair of rocking rollers 107 are in contact with the eccentric cam 105, and when the eccentric cam 105 rotates, the second protrusion 106 swings in the rocking direction following the rotation. That is, this swing is also transmitted to the swing plate 103 via the second protrusion 106, so that the swing plate 103 and the fixing unit 200 are also swung in the swing direction.

JP 2004-317843 A

However, with the swing mechanism 100 configured as described above, the base 101 is deformed due to its own weight or heat, the flatness of the lower surface, etc., as shown in FIG. There was a possibility that the positional relationship with 107 would collapse. Such positional deviation causes a gap S between the eccentric cam 105 and the swinging roller 107, which is a cause of hindering accurate swinging.
An object of the present invention is to suppress the deformation of the swing plate and to enable accurate swing of the fixing unit.

According to a first aspect of the present invention, there is provided an image forming apparatus.
A fixing unit;
A swinging mechanism that swings the fixing unit along a swinging direction orthogonal to the paper transport direction;
The swing mechanism is
A swing plate disposed below the fixing unit;
A connecting member that connects the fixing unit and the swing plate so that a relative positional relationship is not shifted in the swing direction;
A base disposed below the swing plate;
Fixing that supports the fixing unit with a predetermined interval between the fixing unit and the swinging plate in a state in which the relative positional relationship between the swinging direction of the base and the fixing unit is freely changeable. A support member for the unit;
A swing part for swinging the swing plate with respect to the base,
The rocking part is
An eccentric cam attached to the base and rotatable;
A pair of rocking rollers attached to the rocking plate so as to contact the eccentric cam in the rocking direction;
When the rocking roller moves in the rocking direction by the rotation of the eccentric cam, the rocking plate rocks in conjunction with the movement.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect,
The swing mechanism is
The base plate and the swing plate are relatively movable with respect to the base, and a swing plate support member for supporting the swing plate is further provided.

  According to the present invention, deformation of the swing plate can be suppressed, and the fixing unit can be swinged accurately.

1 is a front view illustrating a schematic configuration of an image forming apparatus according to an exemplary embodiment. FIG. 2 is a side view showing a schematic configuration of a swing mechanism provided in the image forming apparatus of FIG. 1. 2A and 2B are explanatory views showing a connection state between a connecting member and a fixing unit provided in the image forming apparatus of FIG. 1, wherein FIG. 2A is a bottom view of the fixing unit, and FIG. It is a side view which shows schematic structure of the conventional rocking | fluctuation mechanism. It is explanatory drawing which shows the problem of the rocking | fluctuation mechanism of FIG.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  A schematic cross-sectional configuration diagram of the image forming apparatus 1 will be described with reference to FIG. The image forming apparatus 1 includes a copy function for reading an image from a document, forming the read image on paper P, and outputting it, page data including image data from an external device or the like, image forming conditions for each image data, and the like. It has a print function for receiving job job data, forming an image on paper P based on the received job data, and outputting the image. As shown in FIG. 1, the image forming apparatus 1 includes an image reading unit 10, an image forming unit 20, a paper feeding unit 25, a transport unit 30, and a swing mechanism 40.

  The image reading unit 10 includes an automatic document feeder 11 called an ADF (Auto Document Feeder) and a reading unit 12. The document d placed on the document tray of the automatic document feeder 11 is conveyed to a contact glass which is a reading location, an image on one or both sides of the document d is read by an optical system, and the document is scanned by a CCD (Charge Coupled Device). The image of d is read.

  The image (analog image signal) read by the image reading unit 10 is subjected to various image processing such as analog processing, A / D conversion processing, shading correction, and image compression processing, and then Y (yellow) and M (magenta). ), C (cyan), and K (black), and are output to the image forming unit 20 as digital image data.

  The image forming unit 20 performs electrophotographic image forming processing based on the input image data. The image forming unit 20 includes exposure units 2Y, 2M, 2C, and 2K, developing units 3Y, 3M, 3C, and 3K, photosensitive drums 4Y, 4M, 4C, and 4K, and charging units 5Y, 5M, 5C, and 5K. , Cleaning units 6Y, 6M, 6C, and 6K, primary transfer rollers 7Y, 7M, 7C, and 7K, an intermediate transfer belt 8, a belt cleaning unit 9, a secondary transfer roller 21, and a fixing unit 22. Configured.

  The exposure units 2Y, 2M, 2C, and 2K include a laser light source such as an LD, a polygon mirror, and a plurality of lenses. The exposure units 2Y, 2M, 2C, and 2K scan and expose the surfaces of the photosensitive drums 4Y, 4M, 4C, and 4K with a laser beam based on image data sent from the CPU 51. By this laser beam scanning exposure, latent images are formed, that is, images are written at the image forming positions of the photosensitive drums 4Y, 4M, 4C, and 4K charged by the charging units 5Y, 5M, 5C, and 5K. The image forming positions of the photoconductor drums 4Y, 4M, 4C, and 4K are positions where a latent image is formed on the photoconductor drum.

  The latent images formed on the photoconductive drums 4Y, 4M, 4C, and 4K are visualized by development by the corresponding developing units 3Y, 3M, 3C, and 3K, and are formed on the photoconductive drums 4Y, 4M, 4C, and 4K. A toner image is formed on.

  The toner images formed and carried on the photosensitive drums 4Y, 4M, 4C, and 4K are sequentially transferred to a predetermined position on the intermediate transfer belt 8 by the primary transfer rollers 7Y, 7M, 7C, and 7K, and are primarily transferred. .

  Residual toner is removed from the surfaces of the photosensitive drums 4Y, 4M, 4C, and 4K after the transfer of the toner image by the cleaning units 6Y, 6M, 6C, and 6K.

The intermediate transfer belt 8 is a semiconductive endless belt that is suspended and supported rotatably by a plurality of rollers, and is driven to rotate as the rollers rotate.
The intermediate transfer belt 8 is pressure-bonded to the respective photosensitive drums 4Y, 4M, 4C, and 4K by primary transfer rollers 7Y, 7M, 7C, and 7K. As a result, the toner developed on the surfaces of the photosensitive drums 4Y, 4M, 4C, and 4K is transferred (primary transfer) to the intermediate transfer belt 8 at the transfer positions by the primary transfer rollers 7Y, 7M, 7C, and 7K. At the transfer position by the secondary transfer roller 21, yellow, magenta, cyan, and black toners are sequentially transferred onto the paper P and transferred (secondary transfer). The intermediate transfer belt 8 transfers the toner image onto the paper P by the secondary transfer roller 21 and then separates the paper P from the curvature and electrostatically, and the residual toner is removed by the belt cleaning unit 9.

  The fixing unit 22 thermally fixes the toner image transferred to the paper P. As a result, the toner image is fixed on the paper P and an image is formed. The paper P that has been subjected to the fixing process by the fixing unit 22 is discharged to the paper discharge tray 91.

  That is, image formation by the image forming unit 20 is a series of operations including an operation of forming latent images at the image writing positions of the photosensitive drums 4Y, 4M, 4C, and 4K by the exposure units 2Y, 2M, 2C, and 2K. That means. Specifically, the image formation by the image forming unit 20 is formed by forming latent images at the image writing positions of the photosensitive drums 4Y, 4M, 4C, and 4K by the exposure units 2Y, 2M, 2C, and 2K. This means a series of operations in which the toner image with the toner attached to the latent image is transferred to the intermediate transfer belt 8 and further transferred onto the paper P, and the toner image on the paper P is thermally fixed by the fixing unit 22.

  The paper feed unit 25 includes a plurality of paper feed trays 25a, 25b, and 25c and a paper feed unit 25d. In the paper feed trays 25a, 25b, and 25c, paper P such as standard paper and special paper such as tab paper and cutting paper identified based on the amount and size of the paper is stored for each preset type. Yes. The paper feed unit 25d feeds the paper P stored in each paper feed tray one by one from the top toward the transport unit 30.

  The transport unit 30 includes a transport roller mechanism for transporting the paper P fed from the paper feed unit 25 and a transport path that is a transport path of the paper P. The transport unit 30 includes a loop roller 31 and a registration roller 32 as a transport roller mechanism for transporting the paper P.

The swing mechanism 40 swings the fixing unit 22 along a swing direction orthogonal to the transport direction of the paper P.
FIG. 2 is a side view schematically showing a schematic configuration of the swing mechanism 40. In FIG. 2, the direction from the front to the back is the transport direction X of the paper P, and the direction orthogonal to the transport direction is the swing direction Y. The swing mechanism 40 includes a swing plate 41, a connecting member 42, a base 43, a fixing unit support member 44, a swing plate support member 45, and a swing portion 46.

The swing plate 41 is a plate-like member made of metal, and is disposed below the fixing unit 22 with a predetermined interval R1. The swing plate 41 includes a pair of second protrusions 411 that extend downward from the center of the lower surface and are disposed at a predetermined interval.
The connecting member 42 connects the fixing unit 22 and the swing plate 41 so that the relative positional relationship in the swing direction Y does not shift. The connecting member 42 is fixed to both ends of the upper surface of the swing plate 41. The connecting member 42 includes a shaft body 421 fixed to the swing plate 41, and a shaft head 422 having an outer diameter larger than that of the shaft body 421 at the upper portion of the shaft body 421. An insertion hole 221 into which the connecting member 42 is inserted is formed on the lower surface of the fixing unit 22. In the present embodiment, the shaft head portion 422 of the connecting member 42 is detachably engaged with the insertion hole 221 so that the relative positional relationship between the fixing unit 22 and the swing plate 41 in the swing direction Y is established. It is designed not to slip.
3A and 3B are explanatory views showing a connection state of the connecting member 42 and the fixing unit 22, wherein FIG. 3A is a bottom view of the fixing unit 22, and FIG. 3B is a side view of the connecting member 42 and the fixing unit 22. The insertion hole 221 includes a large-diameter portion 222 having an inner diameter larger than that of the shaft head portion 422 of the connecting member 422 and a slit 223 extending from a part of the large-diameter portion 222 along the swing direction Y. The slit 223 has a width larger than the outer diameter of the shaft body 421 of the connecting member 422 and smaller than the shaft head portion 422. A space 224 into which the shaft head 422 can enter is formed on the back side of the slit 22. If the shaft head 422 is inserted into the insertion hole 221 and the fixing unit 22 is moved to the left in the figure, the shaft body 421 enters the slit 22 and the shaft head 422 is prevented from coming off. After that, if a cover 225 that restricts the movement of the connecting member 422 in the swing direction Y is attached to the lower surface of the fixing unit 22, the relative positional relationship in the swing direction Y between the fixing unit 22 and the swing plate 41 can be obtained. It is fixed so as not to slip.

The base 43 is a plate-shaped member made of metal, is disposed below the swing plate 41, and is fixed to a frame (not shown) of the transport unit 30. The base 43 may be fixed to a structure inside the image forming apparatus 1 other than the frame of the transport unit 30. The base 43 is disposed opposite to the swing plate 41 with a predetermined interval R2. The base 43 includes a first protrusion 431 that extends downward from the center of the lower surface and is disposed between the pair of second protrusions 411.
The fixing unit support member 44 and the swing plate support member 45 are, for example, rollers, and these rollers are rotatably supported by the base 43. A pair of fixing unit support members 44 are attached to both ends of the base 43, and support the fixing unit 22 on the outer peripheral surface thereof. On the other hand, a pair of swing plate support members 45 are attached inside the fixing unit support member 44 on the base 43 so as to sandwich the first protrusion 431 and support the swing plate 41 on the outer peripheral surface thereof. is doing.
In the present embodiment, the case where the fixing unit support member 44 and the swing plate support member 45 are rollers has been described as an example, but these may be other than rollers. That is, any member may be used as long as the fixing unit 22 and the swing plate 41 can smoothly move in the swing direction with respect to the base 43 during the swing. For example, instead of the roller, a roller, a bearing, a fixing unit 22 or a support column with a lubricant applied to the contact surface with the swing plate 41 may be used.

  The swinging portion 46 is for swinging the swinging plate 41 with respect to the base 43 and is disposed between the pair of swinging plate support members 45. The swinging part 46 includes an eccentric cam 461 that is rotatably attached to the first protrusion 431 of the base 43 and a pair of swinging rollers that are rotatably attached to the second protrusion 411 of the swinging plate 41. 462. The pair of rocking rollers 462 are, for example, rollers, and are attached to the second projecting portion 411 so as to sandwich the eccentric cam 461 in the rocking direction Y and come into contact with the eccentric cam 461, respectively. The eccentric cam 461 is rotated by a motor (not shown), and the pair of swing rollers 462 swing back and forth in the swing direction Y following the rotation amount. This swing is also transmitted to the swing plate 103 via the pair of second protrusions 411, and is also transmitted from the swing plate 103 to the fixing unit 22 via the connecting member 42. For this reason, the swing plate 41 and the fixing unit 22 also swing in the swing direction Y. Thus, when the rocking roller 462 moves in the rocking direction Y by the rotation of the eccentric cam 461, the rocking plate 41 rocks in conjunction with the movement.

During this swing, the fixing unit 22 swings while being supported by the fixing unit support member 44, and the swing plate 41 swings while being supported by the swing plate support member 45. The predetermined distance R1 between the fixing unit 22 and the swing plate 41 remains secured. As described above, since the interval R1 is secured, it is possible to suppress the weight of the fixing unit 22 from directly acting on the swing plate 41, and to prevent the swing plate 41 from being deformed by the weight of the fixing unit 22. be able to. Even if the flatness of the lower surface of the fixing unit 22 is poor, the fixing unit 22 is not in direct contact with the swinging plate 41, so that the swinging plate 41 may be deformed by the shape of the lower surface of the fixing unit 22. Can be prevented. Further, the temperature of the fixing unit 22 increases to about 200 degrees during image formation, but the amount of heat is also prevented from being directly conducted to the swinging plate 41 by the interval R1 between the fixing unit 22 and the swinging plate 41. For this reason, it is possible to prevent the rocking plate 41 from being thermally deformed.
For these reasons, the positional relationship between the eccentric cam 461 of the swinging portion 46 and the swinging roller 462 can be maintained over a long period of time, and the fixing unit 22 can be swinged accurately.

Further, since the weight of the fixing unit 22 is not applied to the rocking plate 41, it is not necessary to increase the strength of the rocking plate 41, and low-cost materials can be used and the thickness can be reduced. Can be suppressed.
Further, since the connecting member 42 and the fixing unit 22 are detachable, the fixing unit 22 can be easily detached from the swing mechanism 40, and the exchangeability of the fixing unit 22 can be improved.
Note that the present invention is not limited to the above embodiment, and can be modified as appropriate.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 22 Fixing unit 40 Oscillating mechanism 41 Oscillating plate 42 Connecting member 43 Base 44 Fixing unit support member 45 Oscillating plate support member 46 Oscillating part 221 Insertion hole 411 Second protrusion 421 Shaft body 422 Shaft head 431 First protrusion 441 Oscillating plate 461 Eccentric cam 462 Oscillating roller P Paper R1 Interval X Conveying direction Y Oscillating direction

Claims (2)

A fixing unit;
A swinging mechanism that swings the fixing unit along a swinging direction orthogonal to the paper transport direction;
The swing mechanism is
A swing plate disposed below the fixing unit;
A connecting member that connects the fixing unit and the swing plate so that a relative positional relationship is not shifted in the swing direction;
A base disposed below the swing plate;
Fixing that supports the fixing unit with a predetermined interval between the fixing unit and the swinging plate in a state in which the relative positional relationship between the swinging direction of the base and the fixing unit is freely changeable. A support member for the unit;
A swing part for swinging the swing plate with respect to the base,
The rocking part is
An eccentric cam attached to the base and rotatable;
A pair of rocking rollers attached to the rocking plate so as to contact the eccentric cam in the rocking direction;
2. An image forming apparatus according to claim 1, wherein when the swing roller moves in the swing direction by rotation of the eccentric cam, the swing plate swings in conjunction with the movement. The image forming apparatus according to claim 1.
The swing mechanism is
An image forming apparatus, further comprising: a swing plate support member that is provided in a state in which the base and the swing plate are relatively movable with respect to the base, and supports the swing plate. apparatus.

Images