JP2018104138A - Post-processing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique in which even if a toner adheres to another paper, stain of the toner is hardly conspicuous in the paper.SOLUTION: A post-processing device includes rake rollers 23 for guiding paper conveyed to a discharge position in a normal direction to a post-processing position by moving the paper to a reverse direction in the middle. Projecting parts 232 are formed on a peripheral surfaces 23a of the rake rollers 23, and the projecting parts 232 are formed so that a contact position with the paper moves in an axial direction D1 of the rake roller 23 as the rake rollers 23 rotate.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a post-processing technique for an image-formed sheet.

  A post-processing device that performs post-processing of image-formed paper leads the paper conveyed in the forward direction toward the discharge position to the post-processing position by moving the paper in the reverse direction by a scraping roller in the middle. There exist many (for example, refer patent document 1). In such a post-processing apparatus, a plurality of paper sheets are aligned and stacked at the post-processing position, and then post-processing is performed on these paper sheets.

JP 2013-212911 A

  However, when the paper is guided to the post-processing position by the scraping roller, the paper receives a pressing force necessary for conveyance from the scraping roller. For this reason, if the toner is insufficiently fixed on the paper on which the image is formed, when the paper is overlapped with another paper (that is, the paper immediately below) and the pressing force is applied from the scraping roller, the toner is not There was a problem of sticking to another sheet. Then, due to the adhesion of such toner, another sheet is conspicuously stained in an area corresponding to the width of the take-in roller.

  In particular, the above problem is likely to occur when an image is formed on a sheet with an intermediate density such as halftone. In recent years, the particle size of toner has become smaller with higher image quality and higher definition. Therefore, particularly in printing at an intermediate density, it is difficult for toners to be combined with each other, and the adhesive force of toner to paper tends to be weakened. . For this reason, the toner tends to adhere to another sheet due to the pressing force of the take-in roller.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a technique that makes it difficult for toner stains to be noticeable on another sheet even if the toner adheres to another sheet.

  The post-processing apparatus according to the present invention includes a take-up roller that guides the paper conveyed in the forward direction toward the discharge position to the post-processing position by moving the paper in the reverse direction. And the convex part is formed in the surrounding surface of the pick-up roller, The said convex part is formed so that the contact position with a paper may move in the axial direction of the said pick-up roller with rotation of the pick-up roller. Has been.

  According to the post-processing device, when the paper is guided to the post-processing position by the scavenging roller, the paper receives a pressing force from the convex portion of the scoring roller. As described above, the convex portion is formed so that the position of contact with the paper moves in the axial direction of the scraping roller as the scraping roller rotates. Therefore, even if the toner is not sufficiently fixed on the image-formed paper and the toner may adhere to another paper (that is, the paper immediately below), the toner is attached at the position of the convex portion and the paper. It moves in the width direction according to the contact position. Therefore, in the area corresponding to the width of the scavenging roller on the other sheet, the toner does not adhere to the same position in the width direction (that is, the toner is scattered to the left and right), and as a result, overall The toner becomes thinner.

  In the post-processing apparatus, the convex portion is preferably formed so that the position of contact with the paper moves in one direction in the axial direction of the scraping roller as the scraping roller rotates. According to this configuration, the frictional force generated in the paper guided to the post-processing position (the frictional force in the same direction as the movement direction of the contact position) becomes one direction, and thus the direction in which the paper is pulled by the frictional force is stabilized. be able to. And as such a structure, it is preferable that the convex part is helically formed around the axis | shaft of the pick-up roller.

  In the post-processing apparatus, two of the scavenging rollers may be provided coaxially. In this case, each of the two pick-up rollers is provided with a convex portion, and these two convex portions are formed so that the respective contact positions with the paper move in opposite directions with the rotation of the pick-up roller. It is preferable that According to this configuration, the paper guided to the post-processing position generates a frictional force in the same direction as the movement direction of the two contact positions (the direction from the inner side to the outer side). Will be pulled to. Therefore, the sheet is guided to the post-processing position in a stable state without shifting the position in the width direction from side to side.

  As another example, each of the two picking rollers is provided with a convex portion, and these two convex portions are arranged such that their respective contact positions with the paper move in the same direction as the picking roller rotates. It may be formed. According to this configuration, it is possible to align the sheets on the basis of one side (for example, the front side or the back side of the post-processing apparatus).

  An image forming apparatus according to the present invention includes a main processing apparatus that forms an image on a sheet, and the post-processing apparatus that performs post-processing of the sheet on which the image is formed.

  According to the present invention, even when toner adheres to another sheet, the toner is less noticeable on the sheet.

1 is a front view conceptually showing an image forming apparatus according to a first embodiment. 3 is a conceptual diagram partially showing an internal structure of a post-processing device provided in the image forming apparatus. FIG. (A) (B) It is the perspective view which showed the specific structure of the pick-up roller and backup roller with which a post-processing apparatus is provided. It is the figure which planarly viewed the take-in roller from the direction perpendicular | vertical to a rotating shaft. FIG. 5 is a diagram illustrating sheet transport operations in order. FIG. 5 is a diagram illustrating sheet transport operations in order. It is the figure which planarly viewed the scraping roller in 2nd Embodiment from the direction perpendicular | vertical to a rotating shaft. It is the figure which planarly viewed the raking roller in 3rd Embodiment from the direction perpendicular | vertical to a rotating shaft. It is the figure which showed the other example of the take-in roller.

[1] First Embodiment FIG. 1 is a front view conceptually showing an image forming apparatus according to a first embodiment. As shown in FIG. 1, the image forming apparatus includes a main processing apparatus 1 that forms an image on a sheet and a post-processing apparatus 2 that performs post-processing of the sheet on which the image has been formed.

  The main processing apparatus 1 includes an image reading unit 11, a paper feeding unit 12, an image forming unit 13, and an operation unit 14. The image reading unit 11 generates image data by optically reading an image of a document placed on a document table. Note that the image reading unit 11 may include an automatic document feeding mechanism. The sheet feeding unit 12 supplies the sheets stored therein to the image forming unit 13 one by one. The paper is not limited to a sheet of paper such as plain paper or photographic paper, but includes a sheet of resin material such as an OHP film, and sheets formed of various other materials. The paper feed unit 12 is not limited to a paper feed cassette, and may include a manual feed tray.

  The image forming unit 13 performs image formation (printing) on a sheet fed from the paper feeding unit 12 by performing an electrophotographic image forming process based on the image data. Specifically, the image forming unit 13 forms an image on a sheet by transferring a toner image formed on an image carrier such as a photosensitive drum or an intermediate transfer belt onto the sheet, and then fixing the toner image. . Note that the image data is not limited to that generated by the image reading unit 11, but may be obtained from an external information processing apparatus via a network or the like.

  The operation unit 14 is a touch panel, for example, and functions as a user interface. That is, the operation unit 14 has a function as an input unit to which an operation command from a user is input and a function as a display unit that gives information such as an operation state to the user.

  FIG. 2 is a conceptual diagram partially showing the internal structure of the post-processing apparatus 2. As shown in FIG. 2, the post-processing device 2 includes a main path 20A, a sub-path 20B, a paper tray 21, a transport roller 22, a scavenging roller 23, a backup roller 24, an alignment roller 25, A post-processing unit 26.

  The main path 20A reaches the discharge position P1 on the paper tray 21 through which the image-formed paper is conveyed from the main processing device 1 to the post-processing device 2 and then passes through the main body 20 of the post-processing device 2. It is a route. In the present embodiment, the main body 20 of the post-processing device 2 is provided with an inlet 201 through which paper is fed from the main processing device 1 and an outlet 202 through which paper is fed to the paper tray 21. It extends in the horizontal direction through the outlet 202 from 201 to the discharge position P1.

  The sub-path 20B is a path branched from the main path 20A in the direction opposite to the forward direction toward the discharge position P1, and is a path to the post-processing position P2 where the post-processing for the sheet is executed. In the present embodiment, the sub route 20B extends obliquely downward (downward rightward in FIG. 2) from the branch point P3 located in the vicinity of the exit 202 to the post-processing position P2.

  The transport roller 22 is a roller that transports the paper in the forward direction along the main path 20A. In the present embodiment, the conveyance roller 22 is provided at each position on the upstream side and the downstream side of the main path 20 </ b> A between the inlet 201 and the outlet 202.

  The take-in roller 23 and the backup roller 24 are respectively provided up and down at the branch point P3 or in the vicinity thereof so that both the main path 20A and the sub-path 20B pass between them. The take-in roller 23 is a driving roller, and moves up and down between a separation position that is spaced upward from the backup roller 24 and a pressing position that approaches or abuts the backup roller 24 and applies a downward pressing force. Can do. The backup roller 24 is a driven roller for receiving the pressing force from the scraping roller 23 arranged at the pressing position from the lower side, and is disposed to face the scraping roller 23.

  Specifically, the support portion 231 is pivotally supported in the vicinity of the downstream side conveyance roller 22 in the main body 20 of the post-processing apparatus 2. Further, the support portion 231 extends from the pivotally supported position toward the outlet 202, and the distal end portion 231 a is disposed near the outlet 202. Therefore, the support portion 231 can be rotated around a shaft 231b (an axis parallel to the rotation axis of the conveyance roller 22) disposed in the vicinity of the conveyance roller 22 on the downstream side. In the vicinity of 202, the tip 231a can be moved up and down. Then, the scraping roller 23 is rotatably supported by the tip portion 231a of the support portion 231. Further, the support portion 231 is provided with means for urging the scraping roller 23 downward at the pressing position.

  In the present embodiment, the take-in roller 23 can be rotated in either the forward direction or the reverse direction, and rotates forward with the sheet sandwiched between the backup roller 24 and the sheet toward the discharge position P1. Is moved in the reverse direction with the sheet sandwiched between the backup roller 24 and the sheet, and the sheet is moved in the direction opposite to the discharge position P1. Then, the take-in roller 23 guides the sheet moving in the forward direction along the main path 20A to the post-processing position P2 along the sub path 20B by moving the sheet in the reverse direction. The details of the sheet transport operation from the inlet 201 to the post-processing position P2 will be described later (see FIGS. 5A to 6B).

  3A and 3B are perspective views showing specific configurations of the take-in roller 23 and the backup roller 24. FIG. 3A shows a state when the scraping roller 23 is disposed at the separation position, and FIG. 3B illustrates a state when the scraping roller 23 is disposed at the pressing position. Yes. As shown in FIGS. 3 (A) and 3 (B), in this embodiment, the two take-in rollers 23 are provided coaxially, and both are rotatably supported by the distal end portion 231a of the support portion 231. Has been. Further, two backup rollers 24 are provided opposite to each of the two scraping rollers 23 and are arranged coaxially.

  FIG. 4 is a plan view of the take-in roller 23 from a direction perpendicular to the rotation shaft 23b. As shown in FIG. 4, a convex portion 232 is formed on the peripheral surface 23 a of each scraping roller 23. The convex portion 232 is formed such that the contact position with the sheet moves in the axial direction D1 of the scavenging roller 23 as the scoring roller 23 rotates. Specifically, the convex portion 232 is formed in a spiral shape around the axis of the scraping roller 23 (that is, around the rotation shaft 23b). That is, the convex portion 232 is formed such that the contact position continuously moves in one direction in the axial direction D1 as the scraping roller 23 rotates. In addition, it is preferable that the shape of the cross section of the convex part 232 (cross section perpendicular | vertical to the extending direction of the convex part 232) is a shape where the front end edge is flat or gently curved. However, the cross section of the convex portion 232 is not limited to these, and can be appropriately modified.

  In the present embodiment, each of the two picking rollers 23 is provided with a convex portion 232, and the two convex portions 232 are in opposite directions with respect to the sheet in accordance with the rotation of the picking roller 23. It is formed to move to. Specifically, the two protrusions 232 have the same direction (right-handed or left-handed) extending spirally outward (winding direction) with one end (end closer to each other) positioned inside as a reference. It is formed to become. More specifically, the two convex portions 232 are formed symmetrically so that the respective contact positions move from the inside to the outside when the raking roller 23 rotates in the reverse direction. Note that the number of turns of the convex portion 232 extending in a spiral shape is not limited to the three turns shown in FIG. 4, and various modifications are possible.

  A plurality of sheets sequentially conveyed to the post-processing position P2 are stacked in a state where the rear end of the sheets is in contact with a positioning unit 26a (see FIG. 1) provided in the post-processing unit 26. The alignment roller 25 aligns the trailing edge of the sheet by pressing the sheet against the positioning unit 26a immediately before the post-processing unit 26 executes post-processing such as stapling or punching. In this state, the post-processing unit 26 performs post-processing such as stapling and punching on a plurality of stacked sheets.

  FIGS. 5A to 6B are diagrams sequentially illustrating the sheet transport operation from the entrance 201 to the post-processing position P2. In FIG. 5A to FIG. 6B, the paper is indicated by the symbol Z. First, when a sheet is fed from the main processing apparatus 1 to the inlet 201 of the post-processing apparatus 2, the sheet is fed to the main path 20A (see FIG. 2) by the forward rotation of the transport roller 22, as shown in FIG. ) Along the forward direction. At this time, the take-in roller 23 is maintained in a state of being separated from the backup roller 24 (a state of being disposed at the separation position). In the present embodiment, the sheet is fed into the inlet 201 with the image forming surface facing down, and is conveyed in the forward direction as it is.

  Thereafter, as shown in FIG. 5B, when the sheet passes through the upstream conveying roller 22 and the trailing edge of the sheet is separated from the conveying roller 22, the scraping roller 23 moves downward. Thus, the state shifts to a state where the backup roller 24 is pressed (a state where the backup roller 24 is disposed at the pressing position). Then, the take-up roller 23 rotates forward with a sheet sandwiched between the backup roller 24 and the paper. As a result, the sheet continues to be conveyed in the forward direction along the main path 20A (see FIG. 2). At this time, the take-in roller 23 functions as a transport roller.

  Then, as shown in FIG. 6A, when the sheet further passes through the conveyance roller 22 on the downstream side and the trailing edge of the sheet is separated from the conveyance roller 22, the take-in roller 23 moves the backup roller 24. It shifts from forward rotation to reverse rotation with the pressed state (state arranged at the pressing position). As a result, the take-in roller 23 causes the paper conveyed in the forward direction along the main path 20A (see FIG. 2) to pass through the downstream conveyance roller 22 at the rear end (that is, halfway). Move in the opposite direction.

  At this time, the rear end of the sheet hangs downward due to its own gravity by moving away from the conveyance roller 22 on the downstream side. As a result, the trailing edge of the sheet moves from a position on the main path 20A (see FIG. 2) to a position on the sub path 20B (see FIG. 2). That is, the sheet shifts from a state where the rear end faces the entrance 201 to a state where the rear end faces the post-processing position P2. Therefore, by moving the paper in the reverse direction by the reverse rotation of the pick-up roller 23, the paper is guided toward the post-processing position P2 along the sub path 20B as shown in FIG. 6B.

  When the trailing edge of the sheet comes into contact with the positioning unit 26a of the post-processing unit 26, the scraping roller 23 is separated from the backup roller 24, thereby completing the conveyance of the sheet to the post-processing position P2. At this time, the sheet is in a state of being passed between the scraping roller 23 and the backup roller 24 while the rear end thereof is in contact with the positioning portion 26a. Therefore, if the toner is not sufficiently fixed on the sheet, when the next sheet is sandwiched between the scraping roller 23 and the backup roller 24, the toner is immediately below the sheet by the pressing force of the scraping roller 23. Will adhere to the back of the. Here, as a case where the toner is not sufficiently fixed on the sheet, there is a case where an image is formed with an intermediate density such as a halftone.

  According to the post-processing device 2, when the paper is guided to the post-processing position P <b> 2 by the scraping roller 23, the paper receives a pressing force from the convex portion 232 of the scraping roller 23. As described above, the convex portion 232 is formed such that the contact position with the sheet moves in the axial direction D1 of the scavenging roller 23 as the scoring roller 23 rotates. Therefore, even if the toner is insufficiently fixed on the image-formed paper and the toner may adhere to another paper (that is, the paper immediately below), the toner is attached at the position of the convex portion 232 and the paper. It moves in the width direction according to the contact position. Accordingly, toner does not adhere to the same position in the width direction in the region corresponding to the width of the scavenging roller 23 on the other sheet (that is, the toner is scattered to the left and right), and as a result, overall Makes toner stains thinner. Therefore, even when toner adheres to another sheet (that is, a sheet immediately below), the toner is less likely to be noticeable on the sheet.

  Further, in the post-processing apparatus 2, the convex portions 232 are provided on each of the two scraping rollers 23, and the two convex portions 232 have their respective contact positions when the scraping roller 23 rotates in the reverse direction. It is formed to move from the inside to the outside. Accordingly, the paper guided to the post-processing position P2 is subjected to a frictional force in the same direction as the movement direction of the two contact positions (the direction from the inside to the outside). As a result, the paper is pulled to both sides in the width direction. It will be. Therefore, the sheet is guided to the post-processing position P2 in a stable state without shifting in the width direction from side to side.

  In the post-processing apparatus 2, the toner is less noticeable with a simple configuration in which the convex portion 232 is provided on the peripheral surface 23 a of the scavenging roller 23, and the conveyance of the paper to the post-processing position P <b> 2 is stabilized. Has been realized.

[2] Second Embodiment FIG. 7 is a plan view of the scraping roller 23 in the second embodiment from a direction perpendicular to the rotation shaft 23b. As shown in FIG. 7, each of the two scoring rollers 23 is provided with a convex portion 232, and each of the two convex portions 232 has a contact position with the paper in accordance with the rotation of the scoring roller 23. They may be formed so as to move in the same direction. Specifically, the two convex portions 232 have a direction (winding direction) extending in a spiral manner toward the outer side with respect to one end (an end closer to each other) located on the inner side (one is right-handed). , The other is left-handed). More specifically, the two convex portions 232 are formed such that when the scraping roller 23 rotates in the reverse direction, the respective contact positions move to the same side in the width direction.

  According to the scoring roller 23 in the second embodiment, as in the first embodiment, the entire surface is contaminated with toner in an area corresponding to the width of the scoring roller 23 on another sheet (that is, a sheet immediately below). Becomes thinner. Therefore, even when toner adheres to another sheet (that is, a sheet immediately below), the toner is less likely to be noticeable on the sheet. Further, not only when the sheets are aligned based on the center as in the first embodiment, it is possible to align the sheets based on one side (for example, the front side or the back side of the image forming apparatus).

[3] Third Embodiment FIG. 8 is a plan view of the scraping roller 23 in the third embodiment from a direction perpendicular to the rotation shaft 23b. As shown in FIG. 8, the convex portion 232 provided on the scraping roller 23 is formed so that the contact position with the paper continuously moves in one direction as in the first and second embodiments. However, it may be formed so as to move intermittently in one direction. In the present embodiment, the convex portion 232 is formed in a striped pattern on the peripheral surface 23 a of the scraping roller 23. Note that the shape of the convex portion 232 is not limited to the stripe shape and can be variously modified as long as the contact position with the paper can be moved intermittently in one direction.

  According to the scoring roller 23 in the third embodiment, as in the first embodiment, the entire surface is contaminated with toner in an area corresponding to the width of the scoring roller 23 in another sheet (that is, a sheet immediately below). Becomes thinner. Therefore, even when toner adheres to another sheet (that is, a sheet immediately below), the toner is less likely to be noticeable on the sheet.

[4] Other Embodiments FIG. 9 is a view showing another example of the take-in roller 23. As shown in FIG. 9, the convex portion 232 provided on the scraping roller 23 may be formed in a loop shape inclined obliquely with respect to the rotation shaft 23 b around the axis of the scraping roller 23. In this case, when the picking roller 23 rotates, the contact position with the paper reciprocates in the axial direction D1 of the picking roller 23. In this case as well, as in the first embodiment, the toner contamination is reduced overall in an area corresponding to the width of the scavenging roller 23 in another sheet (that is, the sheet immediately below). Therefore, even when toner adheres to another sheet (that is, a sheet immediately below), the toner is less likely to be noticeable on the sheet. Further, the contact position with the sheet can be reciprocated with a simple configuration.

  In addition, the configuration of the convex portion 232 of each of the embodiments described above is a configuration in which the scraping roller 23 functions as a transport roller (that is, in the case of normal rotation), or a transport roller is provided separately from the scraping roller 23. In this case, it can be applied to these transport rollers.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Further, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Main processing apparatus 2 Post-processing apparatus 11 Image reading part 12 Paper feeding part 13 Image forming part 14 Operation part 20 Main body 20A Main path 20B Sub path 21 Paper tray 22 Conveying roller 23 Stuck roller 23a Circumferential surface 23b Rotating shaft 24 Backup roller 25 Alignment roller 26 Post-processing section 26a Positioning section 201 Inlet 202 Outlet 231 Support section 231a Tip section 231b Shaft 232 Convex section D1 Axial direction P1 Discharge position P2 Post-processing position P3 Branch point

Claims (6)

A scraping roller that guides the paper conveyed in the forward direction toward the discharge position to the post-processing position by moving in the reverse direction in the middle,
A convex portion is formed on the peripheral surface of the scavenging roller, and the convex portion is formed such that the contact position with the paper moves in the axial direction of the scoring roller in accordance with the rotation of the scavenging roller. A post-processing device.   The post-processing apparatus according to claim 1, wherein the convex portion is formed so that the contact position moves in one direction in the axial direction with the rotation of the scraping roller.   The post-processing apparatus according to claim 2, wherein the convex portion is formed in a spiral shape around the axis of the scraping roller. Two of the scavenging rollers are provided coaxially,
Each of the two picking rollers is provided with the convex portion, and the two convex portions are formed such that the respective contact positions move in opposite directions with the rotation of the picking roller. The post-processing apparatus according to claim 2 or 3. Two of the scavenging rollers are provided coaxially,
Each of the two picking rollers is provided with the convex portion, and the two convex portions are formed such that the respective contact positions move in the same direction as the picking roller rotates. The post-processing apparatus according to claim 2 or 3. A main processing unit for forming an image on paper;
A post-processing apparatus according to claim 1, which performs post-processing of image-formed paper;
An image forming apparatus.

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