JP6270451B2 - Sheet conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet conveying apparatus capable of correcting sheet skew and an image forming apparatus including the sheet conveying apparatus.

  2. Description of the Related Art Conventionally, a sheet conveying apparatus having a plurality of abutting surfaces capable of abutting the leading edge of a conveyed sheet in the circumferential direction, and having a shutter member that abuts the leading edge of the sheet against the abutting surface and corrects skew of the sheet. It is known (see Patent Document 1).

  When correcting the skew using such a shutter member, the shutter member first places the leading end of the sheet at a position as far away as possible (position close to both ends of the sheet) in the sheet width direction orthogonal to the sheet conveying direction. It is necessary to hit it against the surface. This is because the skewed sheet enters the sheet conveying apparatus from either one of both ends. In addition, due to diversification of conveyed sheets, sheets of various sizes may be conveyed to the sheet conveying apparatus, and in order to support various sheets, a plurality of shutter members that match the sheet size are required. There is a problem that the number of parts increases.

  In response to this, the abutting surface of the shutter member on the end portion side is made to protrude from the abutting surface of the shutter member on the central portion side to provide a phase difference between the abutting surfaces of the shutter members, so that the shutter member is provided at both ends of the sheet. Even when there is no sheet, it is possible to suitably correct the skew of the sheet.

International Publication No. 2011/048668

  Here, when using a reciprocating rocking shutter member that returns the abutting surface that has been retracted to the abutting position when the sheet passes, a plurality of shutter members whose phases of the abutting surface are shifted are attached to the rotating shaft by outsert molding. It was. This is because a plurality of shutter members and a rotating shaft are integrally formed, so that it is difficult to reduce accuracy due to component tolerances.

  However, when using a rotary shutter member that rotates by causing the sheet to abut against a plurality of abutting surfaces provided in the circumferential direction and moves the next abutting surface to the abutting position, if outsert molding, There is a problem that can not be installed. This is because in the case of a rotary shutter member, the conveying roller is arranged coaxially with the rotation axis of the shutter member. Moreover, when attaching a shutter member to a rotating shaft separately, there exists a possibility of causing the fall of the precision of the abutting position of the abutting surface of shutter members. As a result, the accuracy of skew correction may be reduced.

  Therefore, the present invention provides a sheet conveying device that can be easily attached without causing a decrease in the accuracy of the position of the abutting surface, even when a plurality of rotary shutter members are attached to the rotating shaft while changing the phase of the abutting surface. An object of the present invention is to provide an image forming apparatus including the same.

The present invention provides a sheet conveying apparatus including a plurality of driving rollers that convey a sheet conveyed by a sheet conveying unit, a plurality of driven rollers that press against the plurality of driving rollers, the plurality of driving rollers, and the plurality of driven rollers. When there is a plurality of abutting surfaces in the circumferential direction that abut the leading edge of the sheet conveyed by the sheet conveying means at the abutting position upstream of the nip portion in the sheet conveying direction, and the abutting surface is pressed against the sheet, A plurality of shutter members rotating on the same axis as the plurality of driven rollers, abutting surfaces pressed by the sheet are retracted from the sheet conveying path, and a next abutting surface is located at the abutting position, and the plurality of shutter members A rotating shaft having an engaging portion that is coaxial with the driven roller and capable of fixing the shutter member between the driven rollers, and the shutter member is offset in the rotation direction. Is formed at a position, the engaging portion has a plurality of engaged portions engageable with, abutment positions of the abutment surface of said shutter member which is fixed in the axial direction central portion side of the rotary shaft In addition, the plurality of engaged portions are selectively used as the engaging portions so that the abutting position of the abutting surface of the shutter member fixed on the axial end side is positioned upstream of the sheet conveying direction. The plurality of shutter members are fixed to the rotation shaft so that the phases of the abutting surfaces are changed by being engaged.

In the sheet conveying apparatus, the present invention includes a sheet conveying unit that conveys a sheet, and a plurality of abutting surfaces that abut the leading ends of the sheets conveyed by the sheet conveying unit in the circumferential direction, and the abutting surface is a sheet And a plurality of shutter members in which the next abutting surface is positioned at the abutting position and an engaging portion capable of fixing the shutter member. The shutter member is formed at a position offset in the rotation direction, and has a plurality of engaged portions that can be engaged with the engagement portion, and a central portion in the axial direction of the rotation shaft The abutting position of the abutting surface of the shutter member fixed on the axial end side is positioned upstream of the abutting position of the abutting surface of the shutter member fixed on the side in the sheet conveying direction. The plurality of persons Parts and selectively engaged with the engaging portion, so that the abutting surface of the phase change, characterized by securing the plurality of shutter members to the rotating shaft.

  According to the present invention, even when a plurality of rotary shutter members are attached to the rotating shaft while changing the phase of the abutting surface, the plurality of rotary shutter members can be easily simplified without causing deterioration in the positional accuracy of the abutting surface. Can be attached to.

1 is a cross-sectional view schematically showing a printer according to a first embodiment of the present invention. FIG. 3 is a block diagram illustrating a configuration of a control unit of the printer according to the first embodiment. It is a perspective view of the sheet conveyance part which concerns on 1st Embodiment. It is the perspective view which looked at the sheet | seat conveyance part shown in FIG. 3 from the other side. FIG. 6 is an explanatory diagram illustrating a skew correction operation by a sheet conveying unit. It is the figure which looked at the shutter member which concerns on 1st Embodiment from the one side and the other side. It is a perspective view of the shutter axis | shaft which can fix a shutter member. It is a perspective view which shows the state which attached the shutter member to the shutter axis | shaft. It is the figure which looked at the shutter member which concerns on 2nd Embodiment from the one side and the other side. It is a perspective view of the shutter shaft which can fix a shutter member. It is a perspective view which shows the state which attached the shutter member to the shutter axis | shaft.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 11. An image forming apparatus according to an embodiment of the present invention includes an image forming apparatus including a sheet conveying unit as a sheet conveying apparatus capable of correcting skew feeding of a sheet on which an image is formed, such as a copying machine, a printer, a facsimile, and a multifunction machine. Device. In the following embodiments, an image forming apparatus will be described using an electrophotographic laser beam printer (hereinafter referred to as “printer”).

<First Embodiment>
A printer 100 according to a first embodiment of the present invention will be described with reference to FIGS. First, a schematic configuration of the printer 100 will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view schematically showing a printer 100 according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of the control unit 80 of the printer 100 according to the present embodiment.

  As shown in FIG. 1, the printer 100 includes a sheet feeding unit 30 that feeds the sheet S, a sheet feeding unit 40 that feeds the sheet S, an image forming unit 50 that forms an image on the sheet S, and an image A sheet discharge unit 60 for discharging the formed sheet S to the outside of the apparatus. Further, the printer 100 includes a discharged sheet stacking unit 70 on which the discharged sheets S are stacked, and a control unit 80 that controls them.

  The sheet feeding unit 30 includes a feeding sheet stacking unit 31 on which the sheets S are stacked, and a feeding roller (sheet conveying unit) 32 that feeds the sheets S stacked on the feeding sheet stacking unit 31 one by one. It is equipped with. The sheet conveying unit 40 corrects the skew of the sheet S fed by the feeding roller 32 and conveys it to the image forming unit 50. In the present embodiment, the sheet conveying unit that conveys the sheet to the sheet conveying unit 40 will be described using the feeding roller 32. However, the sheet conveying unit is separately provided between the feeding roller 32 and the sheet conveying unit 40. The structure which provides may be sufficient. The sheet conveying unit 40 will be described in detail later.

  The image forming unit 50 exposes the surfaces of four process cartridges 51Y to 51K that form yellow (Y), magenta (M), cyan (C), and black (K) images, and photosensitive drums 53Y to 53K described later. An exposure device 52. Since the four process cartridges 51Y to 51K have the same configuration except that the color of the image to be formed is different, the configuration of the process cartridge 51Y that forms a yellow (Y) image will be described to explain the process cartridge 51M. Description of ~ 51K is omitted.

  The process cartridge 51Y includes a photosensitive drum 53Y, a charging roller that charges the photosensitive drum 53Y, and a developing roller 54Y that develops the electrostatic latent image formed on the photosensitive drum 53Y. The image forming unit 50 includes an intermediate transfer belt 55 on which the toner images on the photosensitive drums 53Y to 53K are primarily transferred, and primary transfer rollers 56Y to 56K that primarily transfer the toner images to the intermediate transfer belt 55. Yes. Further, the image forming unit 50 includes a secondary transfer unit 57 that secondary-transfers the primary-transferred toner image, and a fixing unit 58 that heat-fixes the secondary-transferred toner image.

  As shown in FIG. 2, the control unit 80 includes a CPU 80a that drives and controls the sheet feeding unit 30, the image forming unit 50, the sheet discharge unit 60, and the like, various programs such as an image forming program that executes an image forming operation, and various types of programs. And a memory 80b for storing information and the like. The controller 80 uses these to form an image on the sheet S.

  Next, an image forming operation (image forming control by the control unit 80) of the printer 100 configured as described above will be described. When image information is input from an external PC or the like, the exposure device 52 irradiates laser beams toward the photosensitive drums 53Y to 53K based on the input image information. At this time, the photosensitive drums 53Y to 53K are charged in advance by a charging roller, and an electrostatic latent image is formed on the photosensitive drums 53Y to 53K when irradiated with laser light. Thereafter, the electrostatic latent images are developed by the developing rollers 54Y to 54K, and yellow (Y), magenta (M), cyan (C), and black (K) toner images are formed on the photosensitive drums 53Y to 53K. . The toner images of the respective colors formed on the photosensitive drums 53Y to 53K are superimposed and transferred to the intermediate transfer belt 55 by the primary transfer rollers 56Y to 56K, and are conveyed to the secondary transfer unit 57 by the intermediate transfer belt 55.

  In parallel with the image forming operation described above, the sheets S stacked on the feeding sheet stacking unit 31 are fed one by one toward the sheet conveying unit 40 by the feeding roller 32. The sheet S is corrected in skew by the sheet conveyance unit 40 and is conveyed to the secondary transfer unit 57 at a predetermined conveyance timing, and the toner image on the intermediate transfer belt 55 is transferred by the secondary transfer unit 57. . The sheet S on which the toner image has been transferred is heated and pressed by the fixing unit 58 to fix the toner image, and is discharged out of the apparatus by the sheet discharge unit 60. The sheet S discharged outside the apparatus is stacked on a discharge sheet stacking unit 70 formed at the top of the printer 100.

  Next, the sheet conveying unit 40 described above will be specifically described with reference to FIGS. First, a schematic configuration of the sheet conveying unit 40 will be described with reference to FIGS. 3 and 4. FIG. 3 is a perspective view of the sheet conveying unit 40 according to the first embodiment. FIG. 4 is a perspective view of the sheet conveying unit 40 shown in FIG. 3 as viewed from the opposite side.

  As shown in FIG. 3 and FIG. 4, the sheet conveying unit 40 includes a plurality of driving rollers 19... Arranged in parallel with a driving shaft (rotating shaft) 19 a and a plurality of pressing rollers 19. Conveying rollers (driven rollers) 18. Further, the sheet conveying unit 40 includes a plurality of shutter members (rotating members) 23E, 23F, 23G, and 23H that correct skew of the sheet S, and a cam mechanism (positioning unit) 17 that positions the plurality of shutter members 23E to 23H. And.

  The drive shaft 19a is rotatably supported by the feeding frame 20 substantially parallel to the rotation shafts of the photosensitive drums 53Y to 53K, and is connected to a motor (not shown). The plurality of drive rollers 19 are fixed to the drive shaft 19a at predetermined intervals, and rotate when a rotational drive force of a motor (not shown) is transmitted through the drive shaft 19a. The plurality of conveying rollers 18 are rotatably supported by the feeding frame 20 around a rotation axis that is substantially parallel to the driving shaft 19a, and are in pressure contact with the opposing driving roller 19 to nip and convey the sheet S. Part N (see FIG. 1) is formed. The nip portion N is located on the sheet conveyance path through which the sheet S is fed from the feeding roller 32.

  Each of the plurality of shutter members 23E to 23H has a plurality of abutting surfaces capable of abutting the leading end of the sheet S fed to the feeding roller 32, and the sheet S is abutted against the abutting surface. Correct the skew. In the present embodiment, four abutting surfaces 23a, 23b, 23c, and 23d are provided at equal intervals in the circumferential direction.

  The plurality of shutter members 23E to 23H are fixed to a shutter shaft (rotary shaft) 22 substantially parallel to the drive shaft 19a at a predetermined interval, and are rotated integrally. In the present embodiment, the shutters 23a to 23d of the shutter members 23E and 23H on the axial end side and the abutting surfaces 23a to 23d of the shutter members 23F and 23G on the axial center side are out of phase. The members 23E to 23H are fixed to the shutter shaft 22. Specifically, at the abutting position, the abutting surfaces 23a to 23d of the shutter members 23E and 23H on the end side are located upstream of the abutting surfaces 23a to 23d of the shutter members 23F and 23G on the center side. As shown, the shutter shaft 22 is fixed.

  This is because the abutting surface on the end side is positioned upstream in the sheet conveying direction to speed up the abutting timing. For example, even if there is no shutter member at both ends of the sheet S, the preceding portion of the skewed sheet S This is because the skew is corrected by making it abut against the abutting surface before being nipped. A fixing position and a fixing method when the abutting surfaces 23a to 23d of the plurality of shutter members 23E to 23H are fixed to the shutter shaft 22 by changing the phase will be described in detail later.

  The shutter shaft 22 is rotatably supported at both ends by the feeding frame 20 in a state where the shutter shaft 22 is inserted through the axial through holes formed in each of the plurality of conveying rollers 18. It is located between the conveying rollers 18. That is, the plurality of shutter members 23E to 23H and the plurality of transport rollers 18 are coaxially positioned (the rotation centers coincide).

  The cam mechanism 17 includes a shutter cam 24 fixed to the shutter shaft 22, a pressing member 25 that presses the shutter cam 24, and a shutter spring 27 that biases the pressing member 25. The shutter cam 24 determines the position of the shutter members 23E to 23H in the rotation direction. Specifically, the shutter cam 24 has a predetermined abutting position where the abutting surfaces 23a to 23d of the shutter member 23 can abut against the leading edge of the sheet S. (Locking position) is sequentially positioned. Note that the predetermined abutting position is upstream of the driving roller 19 and the nip portion N of the conveying roller 18 in the sheet conveying direction. In the present embodiment, as described above, the predetermined abutting positions of the abutting surfaces 23a to 23d of the shutter members 23E and 23H are more than the predetermined abutting positions of the abutting surfaces 23a to 23d of the shutter members 23F and 23G. Located upstream of the sheet conveyance direction.

  The shutter cam 24 is formed in a substantially quadrangular shape with a circular arc when viewed from the side, and is provided with recesses 24a, 24b, 24c, and 24d on each side (outer peripheral surface). The pressing member 25 is supported (axially supported) on the feeding frame 20 so as to be swingable about the swinging shaft portion 25a, and presses the outer peripheral surface of the shutter cam 24 with a cam follower 26 provided at the tip. One end of the shutter spring 27 is fixed to the feeding frame 20, and the other end is connected to the pressing member 25. The urging force that presses the shutter cam 24 is applied to the pressing member 25.

  Next, the skew correction operation of the sheet S by the shutter members 23E to 23H of the sheet conveying unit 40 will be described with reference to FIG. FIGS. 5A to 5D are explanatory diagrams for explaining the skew feeding correction operation by the sheet conveying unit 40. 5A to 5D, only the shutter member 23E is shown.

  As shown in FIG. 5A, before the leading edge of the sheet S hits the abutting surface 23a of the shutter member 23E (standby state), the cam mechanism 17 positions the abutting surface 23a at a predetermined abutting position. In this state, the shutter member 23E is on standby. In this state, since the sheet S is not in contact with the abutting surface 23a, the abutting surface 23a of the shutter member 23E remains positioned upstream of the driving roller 19 and the nip portion N of the conveying roller 18 in the sheet conveying direction. The same applies to the shutter members 23F to 23H.

  As shown in FIG. 5B, when the leading end of the leading portion of the sheet S comes into contact with the abutting surface 23a of the shutter member 23E, the sheet S reacts with the reaction force of the holding force of the shutter cam 24 and the shutter shaft 22 and the plurality of shutters. Inertial force of members 23E-23H etc. is received as reaction force. In the present embodiment, in the state shown in FIG. 5B in which the leading edge of the sheet S has just contacted, even if the leading edge of the sheet S presses the shutter member 23E against the reaction force, the shutter members 23E to 23H remain. It does not rotate.

  When the feeding roller 32 further conveys the sheet S, as shown in FIG. 5C, a loop is formed on the leading end side of the sheet S, so that the leading end of the sheet S is also on the abutting surface 23a of the shutter member 23H. follow. Specifically, first, the leading end of the sheet is locked to the abutting surface 23a of the shutter member 23E attached in the vicinity of the leading end of the leading sheet, and the arrow shown in FIG. Starts bending in the y direction. Similarly, the leading edge of the trailing side of the sheet S is locked to the abutting surface 23a of the shutter member 23H attached in the vicinity of the side opposite to the shutter member 23E and starts to bend.

  By a series of these operations, the leading end of the sheet S follows the abutting surface 23a of the shutter members 23E and 23H on the axial end side, so that the leading end of the sheet S is substantially parallel to the rotational axis direction of the drive roller 19. (Skew correction). When the loop of the sheet S further increases in the sheet conveyance path constituted by the conveyance upper guide 28 and the conveyance lower guide 20b, the sheet S comes into contact with the conveyance upper guide 28. When the loop of the sheet S comes into contact with the conveyance upper guide 28, the loop cannot be increased any more, so that the leading edge of the sheet S presses the abutting surface 23a by the rigidity (koshi) of the sheet S. When the abutting surface 23a is pressed against the leading edge of the sheet S, the shutter cam 24 starts to rotate against the urging force of the shutter spring 27, and the shutter members 23E to 23H rotate in the direction of arrow Z shown in FIG. Start. The urging force of the shutter spring 27 is set so as to urge the shutter cam 24 with a force that is weaker than the rigidity of the sheet P.

  As shown in FIG. 5D, when the shutter members 23E to 23H rotate, the leading edge of the sheet S is nipped by the nip portion N of the driving roller 19 and the conveying roller 18, and the sheet S is nipped and conveyed. When the shutter members 23E to 23H pushed by the sandwiched and conveyed sheet S further rotate and the cam follower 26 exceeds the corner (top dead center) of the shutter cam 24, the shutter cam 24 is rotated by the urging force of the shutter spring 27. As a result, the shutter members 23E to 23H also rotate. However, since the sheet S is being conveyed, the next abutting surface 23b cannot be positioned at the abutting position and waits in a state where it abuts on the surface of the sheet S. When the sheet S passes, the shutter members 23E to 23H rotate, and the next abutting surface 23b moves (rotates) to the abutting position.

  The above is repeated every time the sheet S is conveyed, and the abutting surfaces 23a to 23d are sequentially positioned at the abutting position, whereby the skew of the sheet S is corrected by the abutting surfaces 23a to 23d.

  In the above description, the sheet S having a size that can be brought into contact with the shutter members 23E and 23H on the end side has been described. However, the sheet having a size that can be brought into contact with the shutter members 23F and 23G on the center side is described. In this case, the skew correction is performed on the shutter members 23F and 23G on the center side. That is, depending on the size of the sheet S, whether the skew correction is applied to the shutter members 23E and 23H on the end side or the shutter members 23F and 23G on the center side is concerned.

  Also, the shutter members 23E and 23H on the end side are positioned such that the abutting positions of the abutting surfaces 23a to 23d are upstream of the center side shutter members 23F and 23G in the sheet conveying direction (away from the nip portion). ). That is, the abutting timing of the preceding portion of the skewed sheet can be accelerated. Therefore, for example, even when the shutter members are not positioned at both ends in the width direction of the sheet S to be skew-corrected, it is possible to prevent the drive roller 19 and the conveyance roller 18 from being nipped before the skew correction. The conveyance failure can be prevented.

  Next, a fixing position and a fixing method when the abutting surfaces 23a to 23d of the plurality of shutter members 23E to 23H are fixed to the shutter shaft 22 by changing the phase will be described with reference to FIGS. . First, the configuration of the plurality of shutter members 23E to 23H and the shutter shaft 22 for fixing the plurality of shutter members 23E to 23H to the shutter shaft 22 will be described with reference to FIGS. In addition, since the shutter members 23E to 23H have the same shape, the shutter member 23E will be described. FIG. 6 is a view of the shutter member 23E according to the first embodiment viewed from one side and the other side. FIG. 7 is a perspective view of the shutter shaft 22 to which the shutter members 23E to 23H can be fixed.

  As shown in FIG. 6, the shutter member 23E is formed on a pair of engaged portions 23i formed on one surface 23m in the axial direction when attached to the shutter shaft 22, and on the other surface 23n. And a pair of engaged portions 23j. The pair of engaged portions 23i and the pair of engaged portions 23j are inserted through the shutter shaft 22 so as to be engageable with engagement protrusions (engagement portions) 22a described later provided on the shutter shaft 22. It forms toward the abutting surfaces 23a and 23c in the direction orthogonal to the axial direction from the opening hole.

  Further, the pair of engaged portions 22j are provided at positions that are offset by an angle α in the direction opposite to the rotation direction than the pair of engaged portions 22i. That is, the shutter member 23E selectively uses the pair of engaged portions 23i or the pair of engaged portions 23j for engagement with the engagement protrusion 22a of the shutter shaft 22, so that the contact surfaces 23a to 23d The phase can be shifted by an angle α. By shifting the phases of the abutting surfaces 23a to 23d (providing a phase difference), the positions of the abutting surfaces 23a to 23d at the abutting positions are changed. Specifically, when the pair of engaged portions 23i are engaged with the engaging protrusions 22a, the abutting surfaces 23a to 23d are more engaged than when the pair of engaged portions 23j are engaged with the engaging protrusions 22a. The abutting position is upstream in the sheet conveying direction.

  As shown in FIG. 7, the shutter shaft 22 includes the same number (four in the present embodiment) of engagement protrusions 22 a as the shutter members 23 </ b> E to 23 </ b> H. The engaging protrusions 22 a are provided so as to be positioned between the conveying rollers 18 when the shutter shaft 22 is attached to the feeding frame 20. In the present embodiment, the engagement protrusion 22a is configured by inserting an engagement pin into a hole 22b formed in the shutter shaft 22, and the shutter shaft can be easily processed by using the engagement pin. Thus, a shutter shaft with an engaging protrusion can be easily configured.

  Next, a fixing method (attachment method) of the shutter members 23E to 23H to the shutter shaft 22 will be described with reference to FIG. FIG. 8 is a perspective view showing a state in which the shutter members 23E to 23H are attached to the shutter shaft 22.

  First, the shutter members 23E and 23F and the conveying rollers 18 and 18 are alternately inserted from the other side of the shutter shaft 22. Next, the shutter member 23E is retracted to one side from the corresponding hole 22b. Then, an engaging pin is inserted into the corresponding hole 22b to form the engaging protrusion 22a, and the shutter member 23E is moved to the other side to engage the engaging protrusion 22a and the engaged portion 23j. Thereby, the shutter member 23E is fixed to the shutter shaft 22 as shown in FIG. On the other hand, the shutter member 23F is retracted to the other side from the corresponding hole 22b. Then, an engaging pin is inserted into the corresponding hole 22b to form the engaging protrusion 22a, and the shutter member 23F is moved to one side to engage the engaging protrusion 22a and the engaged portion 23i. Accordingly, the shutter member 23F is fixed to the shutter shaft 22 as shown in FIG.

  Similarly, the shutter members 23G and 23H and the conveying rollers 18 and 18 are alternately inserted from one side of the shutter shaft 22. Next, the shutter member 23H is retracted to one side from the corresponding hole 22b. Then, an engaging pin is inserted into the corresponding hole 22b to form the engaging protrusion 22a, and the shutter member 23H is moved to the other side to engage the engaging protrusion 22a and the engaged portion 23j. Thereby, the shutter member 22H is fixed to the shutter shaft 22 as shown in FIG. On the other hand, the shutter member 23G is retracted to the other side from the corresponding hole 22b. Then, an engagement pin is inserted into the corresponding hole 22b to form the engagement protrusion 22a, and the shutter member 23G is moved to one side to engage the engagement protrusion 22a and the engaged portion 23i. Thereby, the shutter member 23G is fixed to the shutter shaft 22 as shown in FIG.

  By attaching the shutter members 23E to 23H as described above, the abutting surfaces 23a to 23d of the shutter members 23E to 23H can be fixed to the shutter shaft 22 by changing the phase. Specifically, the shutter members 23E and 23H can be fixed with the phase rotated by an angle α with respect to the shutter members 23F and 23G. At this time, an engaging pin is inserted into the corresponding hole portion 22b to form the engaging protrusion 22a. For example, the shutter member 23E is attached to the shutter shaft 22 by engaging the engaging protrusion 22a with the engaged portion 23i. Fix it. Therefore, even when the transport roller 18 is arranged on the same axis, the shutter members 23E to 23H can be easily fixed to the shutter shaft 22 in a state of different phases.

  In addition, since the engagement protrusion 22a is configured simply by inserting the engagement pin into the hole 22b provided in the shutter shaft 22, the processing of the shutter shaft 22 is easy. Furthermore, the engaged portions 23i and 23j can be easily processed for the shutter members 23E to 23H. Therefore, it is possible to suppress a decrease in processing accuracy. As a result, it is possible to prevent a decrease in position accuracy of the abutting surfaces 23a to 23d, and to prevent a decrease in skew correction accuracy.

Second Embodiment
Next, a printer according to a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the engaged portions of the shutter members 23E to 23H of the sheet conveying unit 40 are different from the first embodiment. Therefore, the shutter member will be mainly described here, and the other components will be denoted by the same reference numerals and description thereof will be omitted.

  First, the shutter members 123E to 123H will be described with reference to FIGS. Since the shutter members 123E to 123H have the same shape, the shutter member 123E will be described. FIG. 9 is a view of the shutter members 123E to 123H according to the second embodiment viewed from one side and the other side. FIG. 10 is a perspective view of the shutter shaft 22 to which the shutter members 123E to 123H can be fixed.

  As shown in FIG. 9, the shutter member 123 </ b> E has a pair of engaged portions 123 i and a pair of engaged portions 123 j formed on a surface 123 m on one axial side when attached to the shutter shaft 22. . That is, the shutter member 123E is provided with the engaged portion only on one surface, not on both surfaces. The pair of engaged portions 123i are abutting surfaces 123b, 123d in a direction perpendicular to the axial direction from the opening hole through which the shutter shaft 22 is inserted so that the engagement portion 123i can be engaged with the engagement protrusion 22a provided on the shutter shaft 22. It is formed toward. The pair of engaged portions 123j is formed in a direction perpendicular to the axial direction from the opening hole so as to have a phase difference of 90 ° to α ° with respect to the pair of engaged portions 123i.

  Thus, when the shutter members 123E to 123H are attached to the shutter shaft 22, the phase between the shutter shaft 22 and the shutter member 123 can be shifted by an angle of 90 + α depending on which of the engaged portions 123i and 123j is used. Since the shutter members 123E to 123H have the same phase every 90 degrees, the phase can actually be shifted by the angle α.

  Next, a fixing method (attachment method) of the shutter members 123E to 123H to the shutter shaft 22 will be described with reference to FIG. FIG. 11 is a perspective view illustrating a state in which the shutter members 123E to 123H are attached to the shutter shaft 22.

  First, the shutter members 123E and 123F and the conveying rollers 18 and 18 are inserted alternately from the other side of the shutter shaft 22. Next, the shutter member 123E is retracted to the other side from the corresponding hole 22b. Then, an engaging pin is inserted into the corresponding hole 22b to form the engaging protrusion 22a, and the shutter member 123E is moved to one side to engage the engaging protrusion 22a with the engaged portion 23i. Similarly, the shutter member 123F is retracted to the other side from the corresponding hole 22b. Then, an engaging pin is inserted into the corresponding hole portion 22b to form the engaging protrusion 22a, and the shutter member 123F is moved to one side to engage the engaging protrusion 22a and the engaged portion 123j. At this time, the shutter member 123F is rotated to align the engagement protrusion 22a with the engaged portion 123j. As a result, the shutter members 123E and 123F are fixed to the shutter shaft 22 as shown in FIG.

  Next, the shutter members 123G and 123H and the conveying rollers 18 and 18 are alternately inserted from one side of the shutter shaft 22. Then, the shutter member 123H is retracted to the other side than the corresponding hole 22b. Next, an engaging pin is inserted into the corresponding hole 22b to form the engaging protrusion 22a, and the shutter member 123H is moved to one side to engage the engaging protrusion 22a with the engaged part 123i. Similarly, the shutter member 123G is retracted to the other side from the corresponding hole 22b. Then, an engagement pin is inserted into the corresponding hole portion 22b to form the engagement protrusion 22a, and the shutter member 123G is moved to one side to engage the engagement protrusion 22a and the engaged portion 123j. At this time, the shutter member 123G is rotated to align the engaging protrusion 22a with the engaged portion 123j. Accordingly, the shutter members 123G and 123H are fixed to the shutter shaft 22 as shown in FIG.

  As described above, the engaged portions 123a to 123d may be formed on one surface 123m. By forming the engaged portions 123a to 123d on one surface 123m, the processing of the shutter member becomes easy. Also, the versatility of the shutter member is increased. Furthermore, attachment is also facilitated.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above. In addition, the effects described in the embodiments of the present invention only list the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

  For example, in the present embodiment, four shutter members 23E to 23H are used as the plurality of shutter members, but the present invention is not limited to this. There may be three shutter members or four or more shutter members.

  In this embodiment, the electrophotographic printer has been described. However, the present invention is not limited to this. For example, the present invention can also be used for an ink jet printer (image forming apparatus) that forms an image on a sheet by ejecting ink liquid from a nozzle.

18 Conveyor roller (driven roller)
19 Driving roller 22 Shutter shaft (rotating shaft)
22a Engagement protrusion (engagement part)
23a, 23b, 23c, 23d Abutting surface 23E, 23F, 23G, 23H Shutter member 23i, 23j Engaged portion 32 Feed roller (sheet conveying means)
40 Sheet conveying section (sheet conveying device)
50 Image forming unit 100 Printer (image forming apparatus)
S sheet

Claims (6)

A plurality of driving rollers for conveying the sheet conveyed by the sheet conveying means and a plurality of driven rollers in pressure contact with the plurality of driving rollers;
A plurality of abutting surfaces are provided in the circumferential direction for abutting the leading ends of the sheets conveyed by the sheet conveying means at the abutting positions upstream of the nip portions of the plurality of driving rollers and the plurality of driven rollers in the sheet conveying direction. When the abutting surface is pressed by the sheet, the abutting surface is rotated coaxially with the driven rollers, the abutting surface pressed by the sheet is retracted from the sheet conveyance path, and the next abutting surface is at the abutting position. A plurality of shutter members positioned;
A rotating shaft having an engagement portion coaxial with the plurality of driven rollers and capable of fixing the shutter member between the driven rollers;
The shutter member is formed at a position offset in the rotational direction, and has a plurality of engaged portions that can be engaged with the engaging portion,
The abutting position of the abutting surface of the shutter member fixed on the axial end side is more than the abutting position of the abutting surface of the shutter member fixed on the axial center side of the rotating shaft. The plurality of engaged members are selectively engaged with the engaging portions so as to be located upstream in the direction , and the plurality of shutter members are fixed to the rotation shaft so that the phase of the abutting surface changes. To
A sheet conveying apparatus. Sheet conveying means for conveying the sheet;
There are a plurality of abutting surfaces in the circumferential direction that abut the leading edge of the sheet conveyed by the sheet conveying means, and when the abutting surface is pressed by the sheet, the abutting surface pressed by the sheet retracts from the sheet conveying path A plurality of shutter members in which the next abutting surface is located at the abutting position;
A rotating shaft having an engaging portion capable of fixing the shutter member,
The shutter member is formed at a position offset in the rotational direction, and has a plurality of engaged portions that can be engaged with the engaging portion,
The abutting position of the abutting surface of the shutter member fixed on the axial end side is more than the abutting position of the abutting surface of the shutter member fixed on the axial center side of the rotating shaft. The plurality of engaged members are selectively engaged with the engaging portions so as to be located upstream in the direction , and the plurality of shutter members are fixed to the rotation shaft so that the phase of the abutting surface changes. To
A sheet conveying apparatus. The shutter member is formed with the engaged portion offset in the rotation direction on both surfaces in the axial direction when being fixed to the rotation shaft,
Selecting the engaged portion of any one of the surfaces to engage with the engaging portion;
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The shutter member is formed with the plurality of engaged portions offset in the rotation direction on one surface in the axial direction when supported by the rotation shaft,
Selecting any one of the plurality of engaged portions formed on the one surface and engaging the engaging portion;
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The engaging portion is composed of an engaging pin that can be attached to a hole formed in the rotating shaft.
Sheet transport apparatus according to claim 1, any one of 4, characterized in that. A sheet conveying device according to any one of claims 1 to 5 ,
An image forming unit that forms an image on a sheet conveyed to the sheet conveying device;
An image forming apparatus.

Images