CN212873196U - Reverse roller adjustment mechanism and image forming apparatus - Google Patents

Abstract

The utility model provides a reversal roller adjustment mechanism and image forming device. The reverse roller adjustment mechanism of the embodiment includes: a pair of rollers that are disposed so as to face each other with a nip formed therebetween and that convey a recording medium along a reverse conveyance path through the nip; a holder that rotatably supports the roller; a regulating shim having a stepped portion that corrects a deviation in an axial direction of the roller with respect to a conveyance direction when a leading end of the recording medium reaches the nip portion, the regulating shim being provided between the holder and an inner frame of the image forming apparatus; and a fixing member detachably fixing the holder and the adjustment pad to the inner frame. Through the utility model discloses, can rectify the relative position of reversal roller for reversal conveying path.

Description

Reverse roller adjustment mechanism and image forming apparatus

Technical Field

The embodiment of the utility model relates to an inversion roller adjustment mechanism and image forming device.

Background

In the related art, when performing duplex printing, an image forming apparatus performs a reversing operation of reversing a conveying direction of a recording medium to return the recording medium after a printing process on a first side is completed, and performs printing on a second side by a reversing and conveying unit.

However, since the transport distance from the reversing operation position to the transfer position of the second surface is longer than the transport distance of the first surface, when the mounting or size of the reversing member is deviated and a deviation occurs between the roller shaft and the transport path, the second surface of the recording medium is more likely to be deviated from the correct printing position after printing.

SUMMERY OF THE UTILITY MODEL

The utility model provides a can rectify reversal roller adjustment mechanism and image forming device of reversal roller for the relative position of reversal conveying path.

The reverse roller adjustment mechanism of the embodiment includes: a pair of rollers that are disposed so as to face each other with a nip formed therebetween and that convey a recording medium along a reverse conveyance path through the nip; a holder that rotatably supports the roller; a regulating shim having a stepped portion that corrects a deviation in an axial direction of the roller with respect to a conveyance direction when a leading end of the recording medium reaches the nip portion, the regulating shim being provided between the holder and an inner frame of the image forming apparatus; and a fixing member detachably fixing the holder and the adjustment pad to the inner frame.

An image forming apparatus according to another embodiment includes: an image reading section that reads an original to generate image data of the original; a transfer section that forms a toner image on a recording medium according to the image data; a fixing section that fixes the toner image on the recording medium; and a paper discharge unit configured to discharge the recording medium, the paper discharge unit including a reverse roller adjustment mechanism, wherein the reverse roller adjustment mechanism includes: a pair of rollers that are disposed so as to face each other with a nip formed therebetween and that convey a recording medium along a reverse conveyance path through the nip; a holder that rotatably supports the roller; a regulating shim having a stepped portion that corrects a deviation in an axial direction of the roller with respect to a conveyance direction when a leading end of the recording medium reaches the nip portion, the regulating shim being provided between the holder and an inner frame of the image forming apparatus; and a fixing member detachably fixing the holder and the adjustment pad to the inner frame.

Through the utility model discloses, can rectify the relative position of reversal roller for reversal conveying path, the condition of the correct position of printing of deviating from when avoiding the reverse side to print.

Drawings

FIG. 1 is a schematic view of an image forming apparatus according to the present invention;

FIG. 2 is a schematic structural view of the adjusting mechanism of the reverse roller of the present invention;

fig. 3 is an explanatory view of a relationship between an offset amount of a roller of the reverse roller adjusting mechanism and an offset amount of a reverse printing position according to the present invention;

fig. 4 is a schematic perspective view of an adjusting shim of the reverse roller adjusting mechanism of the present invention;

fig. 5 is a schematic perspective view of the reverse roller adjusting mechanism of the present invention.

Detailed Description

Hereinafter, the reverse roller adjusting mechanism and the image forming apparatus according to the embodiment will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals.

For convenience of explanation, coordinate axes are shown in the drawings. The X-axis direction is a lateral direction (hereinafter also referred to as a width direction) of the reverse roller adjustment mechanism and the image forming apparatus. The Y-axis direction is a longitudinal direction (hereinafter also referred to as a height direction) of the reverse roller adjustment mechanism and the image forming apparatus. The Z-axis direction is a depth direction (hereinafter also referred to as a longitudinal direction) of the reverse roller adjustment mechanism and the image forming apparatus. The X-axis direction, the Y-axis direction and the Z-axis direction are orthogonal to each other. The direction of + X (the direction of the arrow along the X axis) is the right side, the direction of + Y (the direction of the arrow along the Y axis) is the upper side, and the direction of + Z (the direction toward the back side in fig. 1) is the rear side, which is the left side, the lower side, and the front side, which are opposite to the above. When the orientations of the + X (+ Y, + Z) direction and the-X (-Y, -Z) direction are not considered (i.e., when both directions are included), they are simply referred to as the X-axis (Y-axis, Z-axis) direction. In the drawings, the structure is shown enlarged, reduced, or omitted as appropriate for convenience of explanation.

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

In fig. 1, a broken line G1 in the drawing is defined as a first conveyance path of the recording medium (sheet) P, and the direction of an arrow V1 is a recording medium first conveyance direction. The broken line G2 is a second conveyance path (i.e., a reverse conveyance path) of the recording medium P, and the direction of the arrow V2 is a second conveyance direction (i.e., a reverse direction) of the recording medium.

As shown in fig. 1, the image forming apparatus 1 of the present embodiment is, for example, a multifunction machine, a printer, a copier, or the like. The image forming apparatus 1 forms an image on a recording medium based on image data read on a document. Next, a case where the image forming apparatus 1 is a multifunction peripheral will be described.

The image forming apparatus 1 has a main body 11. An image reading portion 12 is provided on an upper portion of the main body 11, and the image reading portion 12 is used to read an original to generate image data of the original. The image reading portion 12 is composed of a document conveying portion 13 and a scanner portion 14.

A scanner unit 14 is provided below the document conveying unit 13. The original conveying portion 13 conveys an original to be transferred to the scanner portion 14. The scanner portion 14 has an optical mechanism 15, and the scanner portion 14 reads the original to be transferred conveyed by the original conveying portion 13 or the original to be transferred placed directly on a platen glass of the scanner portion 14 through the optical mechanism 15.

The optical mechanism 15 moves in the lateral direction along the platen glass when reading an image of an original directly placed on the platen glass of the scanner section 14. The optical mechanism 15 reads an original image on one original page line by line. When reading an image of a document conveyed by the document conveying portion 13, the optical mechanism 15 reads the conveyed document at a fixed position shown in fig. 1.

An operation display unit 16 is provided on the front side of the scanner unit 14 and above the main body 11. The operation display unit 16 has a function of receiving an operation by an operator and displaying a state of the image forming apparatus 1. The operation display unit 16 is, for example, a touch panel type liquid crystal display.

The inside of the main body 11 has an internal frame, and various components inside the main body 11 are fixedly connected with the main body 11 through the internal frame. The main body 11 has a transfer portion 17 at the center in the longitudinal direction. The main body 11 includes a plurality of paper feed cassettes 18 in a lower portion thereof for supplying a recording medium to the transfer unit 17. The plurality of paper feed cassettes have substantially the same configuration and are arranged so as to overlap one another in order from the upper side toward the lower side.

The sheet feeding cassette 18 has a sheet feeding mechanism 19. The paper feed mechanism 19 takes out the recording media P one by one from the paper feed cassette 18 and conveys the recording media P to a conveyance path. For example, the paper feeding mechanism 19 may include a pickup roller, a separation roller, and a paper feeding roller.

The paper feed cassette 18 accommodates recording media P of various sizes.

The transfer portion 17 forms a toner image on the recording medium P using toner from the image data read by the scanner portion 14, or image data made by a personal computer or the like.

The transfer portion 17 has a plurality of image forming units 20 that form images using different color toners (e.g., yellow, magenta, cyan, black, etc.), an exposer 21, and an intermediate transfer belt 22. The transfer unit 17 converts the image data into color signals of the respective colors, and controls the exposure unit 21 based on the color signals of the respective colors.

The configuration of the transfer section 17 is not limited to this, and the transfer section may have two or three image forming units, or the transfer section may have five or more image forming units.

The image forming units 20 are arranged in parallel below the intermediate transfer belt 22 (in a direction from the left side to the right side in fig. 1).

The exposure unit 21 irradiates exposure light to each image forming unit 20. The exposer 21 may generate a laser scanning beam as the exposure light. The exposure unit 21 may be configured to include a solid-state scanning element such as a light-emitting diode that generates exposure light. The image forming unit 20 forms an electrostatic latent image on the surface of the photosensitive drum in accordance with the exposure light, and the developing portion of the image forming unit 20 develops the electrostatic latent image into a toner image.

The structures of the respective image forming units 20 are the same as each other except that the colors of the toners are different. Examples of the toner include a decolorable toner which can be decolored (invisible) by an external stimulus (e.g., temperature, light having a specific wavelength, or pressure), and a normal non-decolorable toner. A toner that is decolored by temperature decolors when it reaches a specific decoloring temperature or higher, and develops color when it is equal to or lower than a specific restoration temperature.

The intermediate transfer belt 22 is an endless belt member that circulates, the intermediate transfer belt 22 is stretched over a driving roller 23 and a plurality of driven rollers 24, and the intermediate transfer belt 22 rotates counterclockwise in fig. 1.

The intermediate transfer belt 22 is in contact with the image forming unit 20 from above. A primary transfer roller is disposed above the image forming unit 20 and at a position across the intermediate transfer belt 22. The primary transfer roller is disposed inside the intermediate transfer belt 22. The primary transfer roller transfers the toner image formed on the image forming unit 20 onto the intermediate transfer belt 22 when a primary transfer voltage is applied thereto. After the toner images on the photosensitive drums of the plurality of image forming units 20 are sequentially transferred onto the intermediate transfer belt 22 in such a manner as to overlap each other, toner images formed of the toners of the respective colors are formed.

The secondary transfer roller 25 faces the drive roller 23 across the intermediate transfer belt 22. The contact portion between the intermediate transfer belt 22 and the secondary transfer roller 25 constitutes a secondary transfer position. The driving roller 23 drives the intermediate transfer belt 22 to rotate. When the recording medium P passes through the secondary transfer position, a secondary transfer voltage is applied to the secondary transfer roller 25, and the secondary transfer roller 25 secondarily transfers the toner image on the intermediate transfer belt 22 onto the recording medium P.

A supply section 26 is also disposed above the transfer section 17. The supply unit 26 includes a plurality of toner cartridges that store toners of different colors, and supplies the toners to the developers of the respective image forming units.

Each toner cartridge is provided with a not-shown marker for detecting the type of toner stored in the image forming apparatus 1. The identification portion includes at least information of a color of toner of the toner cartridge and information identifying whether the toner is normal toner or achromatic toner.

A belt cleaner 27 is disposed at a position facing one of the driven rollers 24 across the intermediate transfer belt 22. The belt cleaner 27 removes the residual transfer toner on the intermediate transfer belt 22 from the intermediate transfer belt 22. Specifically, the belt cleaner 27 may be a resin member such as urethane.

A conveyance path from the paper feed cassette 18 to the secondary transfer roller 25 is provided with a pair of conveyance rollers 28 and a pair of registration rollers 29. The pair of transport rollers 28 transport the recording medium P taken out of the paper feed cassette 18 by the paper feed mechanism 19.

The pair of registration rollers 29 align the positions of the leading ends of the recording medium P fed from the pair of feed rollers 28 at the positions where they abut against each other. The mutually abutting positions of the pair of registration rollers 29 constitute registration positions. The pair of registration rollers 29 conveys the recording medium P such that the leading end of the region on the recording medium P to which the toner image is to be transferred reaches the secondary transfer position when the leading end of the toner image reaches the secondary transfer position.

A fixing unit 30 that fixes the toner image to the recording medium P is disposed downstream (upper side in fig. 1) of the secondary transfer roller 25 in the conveying direction of the recording medium P.

A paper discharge unit 31 that discharges the recording medium P is disposed downstream (upper left side in fig. 1) of the fixing unit 30 in the transport direction of the recording medium P, and the paper discharge unit 31 includes a pair of rollers 61. When the image forming apparatus 1 performs single-sided printing, the pair of rollers 61 discharges the recording medium P to the paper discharge portion 31, and the pair of rollers 61 functions as discharge rollers. In the image forming apparatus 1, when the duplex printing is performed, the pair of rollers 61 functions as a reverse roller by conveying the recording medium P to the reverse conveyance path 32 described later after the completion of the simplex printing, and the pair of rollers 61 functions as a discharge roller after the completion of the duplex printing, as in the case of the simplex printing.

A reverse conveyance path 32 is disposed downstream (right side in fig. 1) of the fixing section 30 in the conveyance direction of the recording medium P. The reverse conveyance path 32 guides the recording medium P in a reversed state to the secondary transfer roller 25. The reverse conveyance path 32 is used when double-sided printing is performed.

Next, the structure of the reverse roller adjusting mechanism 6 according to the present invention will be described with reference to fig. 2, 3, 4, and 5.

Fig. 2 is a schematic structural view of the reverse roller adjusting mechanism 6 of the present invention. Fig. 2 is an enlarged view of the structure of the sheet discharging unit 31, and only a part of the structure of the internal frame 40 of the image forming apparatus 1 will be schematically shown.

Fig. 3 is an explanatory diagram of a relationship between an offset amount of the pair of rollers 61 of the reverse roller adjusting mechanism 6 in the axial direction with respect to the conveying direction of the recording medium P and an offset amount in reverse printing of the recording medium P.

Fig. 4 is a perspective view of the adjustment washer 63 of the reverse roller adjustment mechanism 6 according to the present invention.

Fig. 5 is a perspective view of the reverse roller adjusting mechanism 6 according to the present invention.

In the present embodiment, the sheet discharging unit 31 includes the reverse roller adjusting mechanism 6, a sheet discharging tray not shown, and the like.

As shown in fig. 2, the reverse roller adjustment mechanism 6 includes a pair of rollers 61, a holder 62, an adjustment pad 63, and a fixing member 64.

The pair of rollers 61 are formed as rollers having shaft portions at both ends in the axial direction, respectively, and the pair of rollers 61 are rotatably supported by the shaft portions at both ends, respectively. The pair of rollers 61 are disposed in an opposing manner, and thereby a nip portion N that nips and conveys the recording medium P is formed between the two rollers 61.

When the image forming apparatus 1 performs only one-side printing, the pair of rollers 61 functions as discharge rollers. That is, when the recording medium P subjected to only one-side printing is conveyed to the pair of rollers 61 in the first conveying direction V1, the upper roller 61 rotates clockwise in fig. 2, the lower roller 61 rotates counterclockwise in fig. 2, and the pair of rollers 61 discharges the conveyed recording medium P to the outside of the image forming apparatus 1 (for example, to a tray, not shown) through the nip N.

When the image forming apparatus 1 performs duplex printing, the pair of rollers 61 first functions as a reverse roller and then functions as a discharge roller. The portion functioning as the discharge roller is the same as described above.

When the pair of rollers 61 function as the reverse rollers, the rotation direction of each of the pair of rollers 61 is respectively opposite to the rotation direction when functioning as the discharge roller. When the recording medium P having completed the one-side printing is conveyed to the pair of rollers 61 in the first conveying direction V1, the pair of rollers 61 conveys the recording medium in the reverse conveying direction V2 along the reverse conveying path G2 by the nip N, thereafter, the recording medium P is conveyed to the reverse conveying path 32 in the reverse conveying direction V2 and is continuously conveyed back to the secondary transfer roller 25 (fig. 1) along the reverse conveying path G2, and reverse side printing in the same step as the front side printing is performed, and thereafter, the recording medium P reaches the pair of rollers 61 again, and is discharged to the outside of the image forming apparatus 1 by the pair of rollers 61 as the discharge rollers.

The pair of rollers 61 may be driven by a motor inside the image forming apparatus 1 at the same time, or one of the rollers 61 may be driven by the motor as a driving roller and the other roller 61 may be driven as a driven roller as the driving roller rotates.

As shown in fig. 2, since the conveying direction of the leading end portion of the recording medium P conveyed to the nip N is parallel to the lateral direction (parallel to the X direction), the axial direction of the pair of rollers 61 should optimally be set parallel to the longitudinal direction (parallel to the Z-axis direction), that is, the axial direction of the pair of rollers 61 is in a state of being perpendicular to the conveying direction when the leading end of the recording medium P reaches the nip N. The above arrangement allows the leading end of the recording medium P to reach the nip portion N at the same time at each position in the longitudinal direction and to contact with each position in the axial direction of the pair of rollers 61 at the same time, so that the recording medium P does not shift during conveyance due to the respective positions in the longitudinal direction abutting against the pair of rollers 61 one after another when reaching the nip portion N, and therefore, when the recording medium P is conveyed along the reverse conveyance path G2 and printing is performed on the reverse side, a toner image is formed at a correct reverse printing position where the toner image does not shift from the printing position on the reverse side.

However, when the size of the pair of rollers 61 is erroneous at the time of production processing or the mounting position of the pair of rollers 61 is not proper, it may cause a shift in the axial direction of the pair of rollers 61 from the conveying direction when the leading end of the recording medium P reaches the nip N, that is, a state in which both are no longer perpendicular, and for example, when one of both ends in the axial direction of the pair of rollers 61 is shifted to the right or left in the lateral direction, or both ends in the axial direction of the pair of rollers 61 are respectively shifted in opposite directions in the lateral direction, a printing position for reverse printing on the recording medium P passing through the reverse conveying path G2 may be shifted from a printing position after the front printing. This is because the transport distance from the nip portion N (reverse operation position) of the pair of rollers 61 to the reverse printing position is relatively long, and the recording medium P is transported by a plurality of transport rollers, and the recording medium P is constantly transported in an offset manner, and the offset is continuously accumulated.

As shown in fig. 3, the ordinate in fig. 3 represents the amount of deviation (first deviation amount) from the correct printing position in the reverse side printing on the recording medium P, in millimeters. The abscissa indicates the amount of displacement (second amount of displacement) in the axial direction of the pair of rollers 61 as the reverse rollers from the conveyance direction when the leading end of the recording medium P reaches the nip N, and has a unit of millimeters. The origin of the abscissa and ordinate indicates a predetermined position without being shifted.

As shown in fig. 3, it can be seen from fig. 3 that when the second offset amount is 2mm (regardless of the predetermined offset in either of the forward or reverse directions), the first offset amount is 0.7mm (regardless of the predetermined offset in the corresponding direction).

Therefore, it is necessary to maintain the perpendicular relationship of the axial direction of the pair of rollers 61 with respect to the conveyance direction when the leading end of the recording medium P reaches the nip portion N.

As shown in fig. 2 and 5, the holder 62 functions as a frame that supports the pair of rollers 61, and the holder 62 rotatably supports the pair of rollers 61, for example, the pair of rollers 61 is rotatably supported by a bearing provided on the holder 62. The holder 62 is detachably provided on the inner frame 40 of the image forming apparatus 1, and a specific position may be such that the pair of rollers 61 is located at an exit that discharges the recording medium P to the outside of the image forming apparatus 1.

In the present invention, as shown in fig. 2, a spacer 63 is further provided between the holder 62 and the inner frame 40 of the image forming apparatus 1.

As shown in fig. 4, the adjustment pad 63 is formed as an L-shaped sheet member, and the adjustment pad 63 includes a stepped portion 65 and a reinforcing rib 66. The step portion 65 is formed in a substantially rectangular sheet shape, and the step portion 65 forms a part of an L shape. The reinforcing rib 66 is formed in a rectangular sheet shape, and the reinforcing rib 66 forms the other part of the L shape. The step portion 65 has at least two surfaces having different heights on the basis of a rectangular sheet shape, and a step difference is formed by the step portion 65. The stepped portion 65 has three step differences, as shown in fig. 4 for example, and in the present embodiment, three step differences are exemplarily shown to be formed by the first bosses 67, the second bosses 68, and the third bosses 69 protruding from the surface of the stepped portion 65 by different heights. The reinforcing rib 66 functions as a member for reinforcing the rigidity of the adjustment pad 63.

As shown in fig. 2, the holder 62 is in contact with the side of the stepped portion 65 of the adjustment pad 63 on which the step is formed, and the inner frame 40 is in contact with the side of the stepped portion 65 of the adjustment pad 63 on which the step is not formed, whereby the adjustment pad 63 is provided between the holder 62 and the inner frame 40 of the image forming apparatus 1, and the adjustment pad 63 and the holder 62 are detachably provided on the inner frame 40 of the image forming apparatus 1. As shown in fig. 5, in the present embodiment, two adjustment shims 63 are provided at both ends of the holder 62 in the longitudinal direction.

In the present embodiment, since the holder 62 supports the pair of rollers 61, the relative position between the holder 62 and the pair of rollers 61 does not change. When one of both ends in the axial direction of the pair of rollers 61 is offset to the right or left in the lateral direction, or both ends in the axial direction of the pair of rollers 61 are respectively offset in opposite directions in the lateral direction, if either one of both ends in the longitudinal direction of the holder 62 or both ends of the holder 62 are simultaneously moved in the opposite direction to the above offset direction, the pair of rollers 61 are also moved in the opposite direction to the offset direction with the holder 62. The adjustment of the holder 62 corresponds to the adjustment of the pair of rollers 61. Since the stepped portions 65 of the adjustment shims 63 have a plurality of surfaces different in height and only one of the surfaces is in contact with the holder 62 at the same time, the surfaces of the stepped portions 65 of the adjustment shims 63 having a step difference that are in contact with both ends in the longitudinal direction of the holder 62 are changed by moving and fixing the adjustment shims 63 at either one of both ends of the holder 62 or both ends of the holder 62 in the longitudinal direction, and both ends in the longitudinal direction of the holder 62 are moved in the direction opposite to the direction of shifting of the pair of rollers 61 to correct the shifting. That is, the shift in the axial direction of the pair of rollers 61 with respect to the conveyance direction when the leading end of the recording medium P reaches the nip portion N (shift from the perpendicular relationship) can be corrected by the step portion 65 of the regulating pad 63.

As shown in fig. 2, in the present embodiment, the reverse roller adjustment mechanism 6 further includes a fixing member 64, and the fixing member 64 functions as a member for detachably fixing the holder 62 and the adjustment pad 63 to the inner frame 40. As shown in fig. 2 and 5, the fixing member 64 is, for example, a fixing screw, and as shown in fig. 4, a circular through hole 70 is formed on each boss of the step portion 65 of the adjusting washer 63, an internal thread into which the fixing screw is screwed is formed inside the circular through hole 70, and an internal thread into which the fixing screw is screwed is also formed at a position of the holder 62 and the inner frame 40 where the adjusting washer 63 is connected. In this way, the fixing screws as the fixing members 64 are screwed into the holder 62, the adjusting washer 63, and the inner frame 40 in this order to fixedly connect the three. When the retainer 62 needs to be disassembled, the fixing screw is screwed out. This realizes that the adjustment pad 63 and the holder 62 are detachably provided on the inner frame 40 of the image forming apparatus 1.

The step of the step 65 is exemplified by a boss in the above embodiment, but is not limited thereto, and may be a step formed by a fillet, a triangle, or the like having a different height.

In addition, the step differences of the step portions 65 are exemplarily three in the above embodiment, but different numbers of step differences may be provided according to different correction cases. That is to say at least two step differences.

In addition, specific numerical values of the level differences of the stepped portions 65 may be regularly formed, for example, the height difference between each level difference is one millimeter, whereby more accurate adjustment can be achieved according to the relationship between the amount of shift of the reverse-side printing position of the recording medium P and the amount of shift in the axial direction of the paired rollers 61.

The fixing member 64 of the adjustment pad 63 is exemplified by a fixing screw in the above embodiment, but is not limited thereto, and any mechanism may be used as long as the adjustment pad 63 and the holder 62 can be detachably provided on the inner frame 40 of the image forming apparatus 1. Such as bolts, pins, etc.

In the above embodiment, the number of the adjustment shims 63 is two, but the number is not limited to this. In this case, the adjustment washer 63 may be provided on either one of both ends of the holder 62 in the longitudinal direction.

According to at least one embodiment described above, by providing the adjustment shim between the holder and the inner frame for correcting the deviation of the axial direction of the roller with respect to the conveyance direction when the leading end of the recording medium reaches the nip portion, it is possible to adjust the deviation of the position of the reverse side printing due to the deviation of the roller without considering the influence of the dimensional error and the mounting error of the components at the time of the double-side printing, and to avoid the deviation from the correct printing position at the time of the reverse side printing.

While several embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various manners, and various omissions, substitutions, combinations, and changes can be made without departing from the gist of the present invention. These embodiments and modifications are included in the scope and gist of the present invention, and are included in the present invention described in the claims and the equivalent scope thereof.

Claims (10)

1. A reverse roller adjustment mechanism, comprising:

a pair of rollers that are disposed so as to face each other with a nip formed therebetween and that convey a recording medium along a reverse conveyance path through the nip;

a holder that rotatably supports the roller;

a regulating shim having a stepped portion that corrects a deviation in an axial direction of the roller with respect to a conveyance direction when a leading end of the recording medium reaches the nip portion, the regulating shim being provided between the holder and an inner frame of the image forming apparatus; and

a fixing member detachably fixing the holder and the adjustment pad to the inner frame.

2. The reverse roller adjustment mechanism according to claim 1,

the stepped portion of the adjustment washer has a plurality of bosses having different heights.

3. The reverse roller adjustment mechanism according to claim 2,

each of the plurality of bosses is formed with a circular through-hole.

4. The reverse roller adjustment mechanism according to claim 3,

the fixing piece is a fixing screw.

5. The reverse roller adjustment mechanism according to claim 4,

the number of the adjusting gaskets is two, and the two adjusting gaskets are respectively arranged at two ends of the retainer in the length direction.

6. An image forming apparatus, comprising:

an image reading section that reads an original to generate image data of the original;

a transfer section that forms a toner image on a recording medium according to the image data;

a fixing section that fixes the toner image on the recording medium; and

a paper discharge portion that discharges the recording medium, the paper discharge portion having a reverse roller adjustment mechanism,

wherein the reverse roller adjusting mechanism has:

a pair of rollers that are disposed so as to face each other with a nip formed therebetween and that convey a recording medium along a reverse conveyance path through the nip;

a holder that rotatably supports the roller;

a regulating shim having a stepped portion that corrects a deviation in an axial direction of the roller with respect to a conveyance direction when a leading end of the recording medium reaches the nip portion, the regulating shim being provided between the holder and an inner frame of the image forming apparatus; and

a fixing member detachably fixing the holder and the adjustment pad to the inner frame.

7. The image forming apparatus according to claim 6,

the stepped portion of the adjustment washer has a plurality of bosses having different heights.

8. The image forming apparatus according to claim 7,

each of the plurality of bosses is formed with a circular through-hole.

9. The image forming apparatus according to claim 8,

the fixing piece is a fixing screw.

10. The image forming apparatus according to claim 9,

the number of the adjusting gaskets is two, and the two adjusting gaskets are respectively arranged at two ends of the retainer in the length direction.

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