JP6957193B2 - Sheet transfer device and image forming device - Google Patents

Description

The present invention relates to a sheet transporting device for transporting sheets and an image forming apparatus including the same.

Generally, an image forming apparatus such as a printer conveys a sheet fed from a feeding cassette by a transfer roller pair provided in the sheet conveying device, forms an image on the sheet in an image forming unit, and then ejects the sheet. .. Conventionally, a sheet transporting device having a lateral register correction unit that corrects a position in the width direction of a sheet while transporting the sheet has been proposed (see Patent Document 1).

The horizontal register correction unit described in Patent Document 1 has a horizontal register correction roller and a diagonal feed roller that abuts on the horizontal register correction roller to form a nip. The horizontal register correction roller rotates about a rotation axis orthogonal to the sheet transport direction, but the oblique feed roller is viewed from the thickness direction of the sheet to be transported with respect to the rotation axis of the horizontal register correction roller. It rotates around an inclined rotation axis. As a result, the horizontal register correction unit can convey the sheet in the direction inclined in the width direction with respect to the transfer direction by the horizontal register correction roller and the oblique feed roller. Further, the horizontal register correction unit has a reference plate in which the side end portion of the sheet abuts on the side of the side conveyed by the horizontal register correction roller and the oblique feed roller. The horizontal register correction unit corrects the position of the sheet in the width direction by bringing the side end portion of the sheet into contact with the reference plate while transporting the sheet.

Japanese Patent No. 3839990

However, in the sheet transfer device described in Patent Document 1, when the oblique feed roller is driven to rotate due to the rotation of the horizontal register correction roller, a force is generated on the downstream side in the transport direction toward the horizontal register correction roller. The oblique feed roller may rotate about the rotation axis of the lateral register correction roller due to the biting force acting on the downstream side in the transport direction. When the diagonal feed roller rotates around the rotation axis of the horizontal register correction roller, the diagonal feed roller does not come into contact with the horizontal register correction roller with a uniform force at the nip, and the diagonal feed roller and the horizontal register do not come into contact with each other. The correction roller may be unevenly worn.

Therefore, an object of the present invention is to provide a sheet transporting device capable of suppressing uneven wear of the first rotating body and the second rotating body for transporting sheets, and an image forming apparatus including the same.

The present invention provides a sheet conveying apparatus, a first rotating body that applies a force to the sheet toward the third direction rotates around the first rotary axis extending in a first direction, perpendicular to the first direction, The nip is formed by abutting on the first rotating body, and the first direction is viewed from an orthogonal direction parallel to the first direction and the third direction and orthogonal to a predetermined plane along the sheet conveying path. A second rotating body that rotates about a second rotating shaft extending in a second direction intersecting with the first rotating body and conveys a sheet together with the first rotating body at the nip, and the second rotating body becomes the first rotating body. The second rotation so that the urging portion for urging toward, the drive source for driving the first rotating body, and the second rotating body are rotatable and can be brought into contact with and separated from the first rotating body. The second rotating shaft includes a support surface that slidably supports the shaft, and has a downstream shaft portion located on one of the nips in the second direction and on the downstream side in the third direction. The support surface has a downstream support surface that slidably supports the downstream shaft portion, and the downstream support surface is from the upstream side to the downstream side in the third direction with respect to the orthogonal direction. In the orthogonal direction, the second rotating body is inclined in a separating direction away from the first rotating body, and the support surface is in the nip acting on the second rotating body from the first rotating body. tangential acting force, the second rotary shaft acts on the second rotor so as to be parallel to said predetermined plane, and provided we are to be inclined with respect to the perpendicular direction, wherein The downstream support surface is characterized in that the direction of the component force parallel to the downstream support surface of the acting force is formed so as to face the downstream side in the separation direction .

According to the present invention, the acting force acts on the support surface so that the second rotating axis is parallel to a predetermined plane, so that the second rotating body hits the nip with a force substantially equal to that of the first rotating body. In contact with each other, uneven wear of the first rotating body and the second rotating body can be suppressed.

The schematic diagram which shows the structure of the printer which concerns on 1st Embodiment. (A) is a figure which shows the horizontal register correction part which concerns on 1st Embodiment. (B) is an arrow view of the horizontal register correction unit as viewed from arrow A shown in FIG. 2 (a). (C) is an arrow view of the horizontal register correction unit as viewed from arrow B shown in FIG. 2 (a). (A) is a diagram showing a transport roller, a diagonal feed roller, and a transport direction regulating unit according to the first embodiment. (B) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from the arrow C shown in FIG. 3 (a). (C) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from arrow D shown in FIG. 3 (a). (A) is a diagram showing a transport roller, a diagonal feed roller, and a transport direction regulating unit according to a second embodiment. (B) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from the arrow C shown in FIG. 4 (a). (C) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from arrow D shown in FIG. 4 (a). The figure which shows the state which the sheet was conveyed to the transfer roller, the oblique feed roller and the transfer direction regulation part which concerns on 2nd Embodiment. (A) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from the arrow C shown in FIG. 4 (a). (B) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from arrow D shown in FIG. 4 (a). FIG. 1A is a diagram showing a state in which the sheet is conveyed to the transfer roller, the oblique transfer roller, and the transfer direction regulating unit according to the third embodiment. (B) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from the arrow C shown in FIG. 6 (a). (A) is a figure which shows the sheet transfer apparatus which concerns on 4th Embodiment. (B) is an arrow view of the sheet transported by the sheet transport device as viewed from arrow E shown in FIG. 7 (a). (A) is a diagram showing a transport roller, a diagonal feed roller, and a transport direction regulating unit according to a fourth embodiment. (B) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from the arrow F shown in FIG. 8 (a). (C) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from the arrow G shown in FIG. 8 (a). (A) is a diagram showing a transport roller, a diagonal feed roller, and a transport direction regulating section related to a horizontal register correction section, which is a comparative example of the first embodiment. (B) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from the arrow C shown in FIG. 9 (a). (C) is a cross-sectional view of the transport roller, the diagonal feed roller, and the transport direction regulating unit as viewed from arrow D shown in FIG. 9 (a). (A) is a figure which shows the tangential force acting on the upstream shaft part which concerns on the horizontal register correction part which is the comparative example of 1st Embodiment. (B) is a figure which shows the tangential force acting on the downstream shaft part which concerns on the horizontal register correction part. The figure which shows the frictional force acting on the downstream shaft part which concerns on the horizontal register correction part which is the comparative example of 1st Embodiment.

<First Embodiment>
Hereinafter, the image forming apparatus according to the first embodiment of the present disclosure will be described with reference to the drawings. The image forming apparatus according to the first embodiment includes an image forming apparatus including a fixing device capable of fixing a toner image formed on a sheet to the sheet by heating and pressurizing, such as a copier, a printer, a facsimile, and a composite device thereof. It is a device. In the following embodiment, as an example of the image forming apparatus, a printer 1 as an electrophotographic color laser beam printer will be described. As shown in FIG. 1, the printer 1 includes a feeding cassette 10 provided in the printer main body 2 so as to be insertable and retractable, an image forming unit 30 for forming an image on a sheet fed from the feeding cassette 10, and an image forming unit 30. It has a fixing unit 50, a discharge roller pair 60, and a control unit 90. However, the sheet refers to a thin layer recording medium such as paper such as paper or an envelope, plastic film (OHT) for an overhead projector, and cloth.

[Outline configuration of printer]
When the image formation command is output to the printer 1, the image formation process by the image forming unit 30 is started based on the image information input from an external computer or the like connected to the printer 1. The image forming unit 30 includes a cartridge 31 having a photoconductor drum 32, a laser scanner 33, and a transfer roller 34. The laser scanner 33 irradiates the photoconductor drum 32 with the laser beam based on the input image information. At this time, the photoconductor drum 32 is precharged by a charging roller (not shown), and an electrostatic latent image is formed on the photoconductor drum 32 by being irradiated with laser light. After that, this electrostatic latent image is developed by a developing roller (not shown), and a toner image is formed on the photoconductor drum 32.

The feeding cassette 10 has a middle plate 11 on which the sheet S is supported and a spring 12 for urging the middle plate 11 upward, and is the uppermost sheet of the sheet bundle loaded on the middle plate 11. Is held at the feeding position pressed by the feeding roller 13. In parallel with the image forming process described above, the sheet S loaded on the middle plate 11 is fed by the feeding roller 13 in the sheet transporting direction. Further, the feed cassette 10 is provided with a separation pad 14 that comes into contact with the feed roller 13 downstream of the middle plate 11 in the sheet transport direction. The sheets S are separated and sent out one by one by the feeding roller 13 and the separation pad 14. Then, the sheet S sent out by the feeding roller 13 and the separation pad 14 is conveyed to the registration roller pair (resist roller pair) 82 via the conveying roller pair 81. The sheet S is conveyed toward the transfer roller 34 as the image forming operation in the image forming unit 30 progresses while the skew is corrected by the resist roller pair 82. The transfer roller 34 transfers the toner image formed on the photoconductor drum 32 by applying the transfer bias to the sheet S.

The sheet S on which the toner image is transferred by the transfer roller 34 is heated and pressurized by the fixing portion 50 having the heating roller 51 and the pressure roller 52, and the toner image is fixed. Then, the sheet S is discharged from the fixing portion 50 by the conveying roller pair 53 arranged downstream in the sheet conveying direction in the fixing portion 50. In the case of single-sided printing, the sheet S discharged from the fixing portion 50 is discharged to the discharge tray 61 by a discharge roller pair 60 arranged downstream of the fixing portion 50 in the sheet transport direction.

On the other hand, in the case of double-sided printing, the sheet S discharged from the fixing portion 50 is conveyed to the discharge roller pair 60, and is conveyed to the double-sided transfer roller pair 83 by reversing the discharge roller pair 60. The sheet S is conveyed to the horizontal register correction unit 100 as a sheet transfer device arranged downstream of the double-sided transfer roller pair 83 in the sheet transfer direction, and is conveyed by the horizontal register correction unit 100 in the width direction orthogonal to the sheet transfer direction. The position is corrected. The sheet S discharged from the horizontal register correction unit 100 is conveyed to the resist roller pair 82 again by the double-sided transfer roller pair 85 arranged downstream of the horizontal register correction unit 100 in the sheet transfer direction, and then the image forming unit. It is transported to 30 and an image is formed on the back surface. Then, the sheet S having the image formed on both sides is discharged to the discharge tray 61 by the discharge roller pair 60.

The control unit 90 is composed of a computer, and includes, for example, a CPU, a ROM that stores a program that controls each unit, a RAM that temporarily stores data, and an input / output circuit that inputs / outputs signals to and from the outside. The CPU is a microprocessor that controls the entire control of the printer 1, and is the main body of the system controller. The CPU is connected to each drive source, a sensor, and the like via an input / output circuit, exchanges signals with each unit, and controls operations. The ROM stores an image formation control sequence or the like for forming an image on the sheet S.

[Detailed configuration of horizontal register correction unit]
FIG. 2A is a diagram showing a lateral register correction unit 100 viewed from a sheet transport direction D1 as a third direction parallel to a predetermined plane and an orthogonal direction D5 orthogonal to a width direction D2 as a first direction. .. 2 (b) is an arrow view of the horizontal register correction unit 100 as viewed from arrow A shown in FIG. 2 (a) in the width direction D2, and FIG. 2 (c) is a horizontal register correction unit. 100 is an arrow view taken from arrow B shown in FIG. 2A in the width direction D2. As shown in FIGS. 2 (a) to 2 (c), the horizontal register correction unit 100 comes into contact with the transport roller 110 as the first rotating body and the transport roller 110, and transports the sheet S together with the transport roller 110. It includes a diagonal feed roller 120 as a second rotating body.

The sheet S conveyed to the horizontal register correction unit 100 is guided by the sheet transfer path 84 shown in FIG. 1 while being conveyed by the transfer roller 110 and the oblique feed roller 120 along a predetermined plane, and is guided by the horizontal register correction unit 100. It is discharged from 100. That is, the predetermined plane is a sheet transport plane parallel to the sheet transported by the transport roller 110 and the diagonal feed roller 120. In the horizontal register correction unit 100 of the first embodiment, in the orthogonal direction D5, the direction from the transport roller 110 toward the diagonal feed roller 120 is defined as upward, and the direction from the diagonal feed roller 120 toward the transport roller 110 is defined as upward. Is defined as downward and explained.

The transport roller 110 includes a rotating shaft 111 as a first rotating shaft that is supported by the printer main body 2 and extends in the width direction D2, and a roller portion 112 that is provided on the outer periphery of the rotating shaft 111 and comes into contact with the oblique feed roller 120. ,have. The oblique feed roller 120 includes a rotating shaft 121 as a second rotating shaft that is swingably supported in the direction D5 orthogonal to the printer main body 2, and a roller portion of the conveying roller 110 provided on the outer periphery of the rotating shaft 121. It has a roller portion 122 that comes into contact with the 112. Further, a spring 130 as a first urging portion for urging toward the roller portion 112 is fixed to the rotating shaft 121. The roller portion 122 presses the roller portion 112 by the urging force of the spring 130.

The axis L1 as the center of rotation of the rotation shaft 111 extends along the width direction D2. Further, the axis L2 as the rotation center of the rotation shaft 121 is basically arranged parallel to the axis L1 when viewed from the sheet transfer direction D1 and is parallel to the sheet transfer plane. However, the axis L2 extends in the oblique direction D3 as the second direction intersecting the width direction D2 when viewed from the orthogonal direction D5, and is inclined by an angle θs with respect to the axis L1.

The rotating shaft 121 has an upstream shaft portion 123 located on one side in the width direction D2 with respect to the roller portion 122, and a downstream shaft portion 124 located on the other side. The upstream shaft portion 123 is arranged upstream of the sheet transport direction D1 with respect to the rotating shaft 111, and the downstream shaft portion 124 is arranged downstream of the sheet transport direction D1 with respect to the rotating shaft 111. That is, the upstream shaft portion 123 is arranged on the upstream side in the sheet transport direction D1, and the downstream shaft portion 124 is arranged on the downstream side in the sheet transport direction D1. In the horizontal register correction unit 100 of the first embodiment, in the width direction D2, the direction in which the upstream shaft portion 123 is arranged with respect to the roller portion 122 is defined as the left side with respect to the roller portion 122. The direction in which the downstream shaft portion 124 is arranged is defined as the right side and will be described.

The transport roller 110 is rotatable around a rotation shaft 111 extending in the width direction D2 in the first rotation direction R1 for transporting the sheet S in the sheet transport direction D1. The oblique feed roller 120 has a rotation shaft 121 extending in the oblique feed direction D3 so as to convey the sheet S in the oblique feed direction D4 which is orthogonal to the oblique feed direction D3 and faces to the left of the sheet transport direction D1. It can rotate in the second rotation direction R2 at the center. The roller portion 122 is arranged so as to come into contact with the roller portion 112 at the axis intersection C1 where the axis L1 and the axis L2 intersect when viewed from the orthogonal direction D5. That is, the nip N1 as the first nip formed by the roller portion 122 in contact with the roller portion 112 is formed centering on the axial intersection C1 when viewed from the orthogonal direction D5.

Further, a motor M as a drive source is connected to the rotation shaft 111, and the motor M is driven and rotated in the first rotation direction R1 by the driving force of the motor M. When the transport roller 110 is driven and rotated in the first rotation direction R1 in a state of being in contact with the oblique feed roller 120, friction is generated between the roller portion 122 and the roller portion 112 in the nip N1. A tangential force P1 acts on the roller portion 122 as a first acting force in the direction in which the roller portion 122 rotates in the second rotation direction R2 due to friction with the roller portion 112. The tangential force P2 acts on the roller portion 112 as a load on the driving force of the motor M, which is a force having the same magnitude as the tangential force P1 but acting in the opposite direction due to the relationship of action and reaction. Since the tangential force P1 and the tangential force P2 are the forces acting on the nip N1, they are the tangential directions of the roller portion 112 and the roller portion 122 on the nip N1 and are parallel to the sheet transport plane. The oblique feed roller 120 is driven to rotate in the second rotation direction R2 by the tangential force P1.

When the sheet S is conveyed to the nip N1, the friction between the transfer roller 110 and the sheet S imparts a transfer force in the sheet transfer direction D1 from the transfer roller 110 driven by the motor M to the sheet S. NS. A force is applied to the diagonal feed roller 120 from the seat S in the sheet transport direction D1 due to friction between the sheet S and the diagonal feed roller 120. The diagonal feed roller 120 rotates in the second rotation direction R2 by the force in the sheet transport direction D1 applied from the sheet S, and the transport force in the diagonal feed direction D4 due to the friction between the diagonal feed roller 120 and the sheet S. Is given to the sheet S. By applying the conveying force in the sheet conveying direction D1 and the conveying force in the oblique feeding direction D4 to the sheet S, the sheet S is conveyed downstream and to the left of the sheet conveying direction D1. In the following, the conveying force applied to the sheet S from the oblique feeding roller 120 in the oblique feeding direction D4 is also described as the oblique feeding force.

Further, the horizontal register correction unit 100 has a horizontal register reference unit 140 arranged to the left of the roller unit 112 and the roller unit 122. The horizontal register reference unit 140 is formed in a plate shape extending in the sheet transport direction D1 and the orthogonal direction D5, and is provided with a reference surface 141 as a sheet regulation surface on which the left side portion of the sheet S can abut. ing. The horizontal register correction unit 100 conveys the sheet S conveyed to the horizontal register correction unit 100 in the sheet transfer direction D1 by the transfer roller 110, and the reference surface 141 due to the oblique feed force in the diagonal feed direction D4 by the diagonal feed roller 120. Transport towards. The sheet S is conveyed from the position shown by the solid line in FIG. 2A to the position shown by the broken line and pressed against the reference surface 141, so that the position in the width direction D2 is corrected. Since the sheet S pressed against the reference surface 141 is restricted from moving to the left, it is conveyed in parallel with the sheet conveying direction D1 and is discharged from the lateral register correction unit 100.

[Explanation of comparative example]
Here, as a comparative example with respect to the horizontal register correction unit 100 of the first embodiment, the horizontal register correction unit 500 will be described with reference to FIG. 9 (a) is a view of the horizontal register correction unit 500 viewed from the orthogonal direction D5, and FIG. 9 (b) is a cross-sectional view taken along the line CC shown in FIG. 9 (a). c) is a cross-sectional view taken along the line DD shown in FIG. 9 (a). As shown in FIG. 9A, the horizontal register correction unit 500 has a shape fixed to the printer main body 2 on both sides in the oblique direction D3 with respect to the rotation axis 121 of the oblique feed roller 120 and extends in the orthogonal direction D5. It has axial regulation units 125 and 126. The axial regulation portion 125 abuts on the ends of the upstream shaft portion 123 of both ends of the rotary shaft 121 in the oblique direction D3, and the axial regulation portion 126 abuts on the ends of the downstream shaft portion 124. As a result, the rotating shaft 121 is slidably supported in the oblique direction D3 and the orthogonal direction D5, and the movement in the oblique feeding direction D4 is restricted.

Further, the lateral register correction unit 500 has a transport direction regulation unit 550 arranged between the axial direction regulation units 125 and 126 in the oblique direction D3. The transport direction regulating unit 550 is composed of transport direction regulating members 551 to 554 fixed to the printer main body 2. As shown in FIGS. 8 (b) and 8 (c), the transport direction regulating members 551 and 552 are arranged so as to sandwich the upstream shaft portion 123 from the upstream and downstream of the oblique feed direction D4. The transport direction regulating members 535 and 554 are arranged so as to sandwich the downstream shaft portion 124 from the upstream and downstream in the oblique feed direction D4.

Further, the transport direction regulating unit 550 has a contact surface 555 that slidably supports the rotating shaft 121 so that the oblique feed roller 120 can rotate and can be brought into contact with and detached from the transport roller 110. The contact surface 555 is composed of an upstream contact surface 556, 557 and a downstream contact surface 558, 559. The upstream side contact surface 556 is provided on the transport direction regulating member 551 and abuts on the downstream side of the oblique feed direction D4 on the upstream shaft portion 123, and the upstream side contact surface 557 is provided on the transport direction regulating member 552. It comes into contact with the upstream of the oblique feed direction D4 in the upstream shaft portion 123. The downstream contact surface 558 is provided on the transport direction regulating member 553 and abuts on the downstream side of the oblique feed direction D4 on the downstream shaft portion 124, and the downstream contact surface 559 is provided on the transport direction regulating member 554. It comes into contact with the upstream of the oblique feed direction D4 in the downstream shaft portion 124.

The upstream contact surfaces 556,557 and the downstream contact surfaces 558,559 are formed in a planar shape extending in the oblique direction D3 and the orthogonal direction D5. That is, the upstream contact surfaces 556,557 and the downstream contact surfaces 558,559 are arranged so as to be substantially orthogonal to the sheet S conveyed by the transfer roller 110 and the oblique transfer roller 120. The pressing force of the oblique feed roller 120 urged downward by the spring 130 acts perpendicularly to the seat S along the upstream contact surfaces 556,557 and the downstream contact surfaces 558,559.

By the way, the nip N1 is not formed at one point of the axial intersection C1 when viewed from the orthogonal direction D5, but is formed in the vicinity of the axial intersection C1 centered on the axial intersection C1. Therefore, the tangential force P1 is not a force acting at one point of the axial intersection C1 when viewed from the orthogonal direction D5, but a resultant force of the forces dispersed at the nip N1. The tangential force P1 can be decomposed into a tangential force PA and a tangential force PB as shown in FIGS. 9 (a), 10 (a) and 10 (b). The tangential force PA is a resultant force of forces dispersed on the upstream shaft portion 123 side of the axial intersection C1 in the oblique direction D3, and is a force acting on the upstream shaft portion 123. The tangential force PB is a resultant force of forces dispersed on the downstream shaft portion 124 side of the axial intersection C1 in the oblique direction D3, and is a force acting on the downstream shaft portion 124.

In the left nip NA as a region of the nip N1 on the side of the upstream shaft portion 123 from the axis intersection C1, the central CNA is located upstream of the axis L1 in the sheet transport direction D1 when viewed from the orthogonal direction D5. The tangential force PA is a force orthogonal to the straight line L3 connecting the axis L1 and the center CNA of the left nip NA and the axis L2. Since the straight line L3 is inclined in the direction opposite to the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2, the tangential force PA is above the sheet transport plane, that is, the tangential force P1. It is a force that faces. The tangential force PA faces a direction inclined by an angle θA in the first rotation direction R1 with respect to the upstream contact surface 556 when viewed from the width direction D2, and the angle θA is 90 degrees or less.

In the right nip NB as a region of the nip N1 on the side of the downstream shaft portion 124 from the axis intersection C1, the central CNB is located downstream of the axis L1 in the sheet transport direction D1 when viewed from the orthogonal direction D5. The tangential force PB is a force orthogonal to the straight line L4 connecting the axis L1 and the center CNB of the right nip NB and the axis L2. Since the straight line L4 is inclined in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2, the tangential force PB is a force pointing downward from the tangential force P1. The tangential force PB faces a direction inclined by an angle θB in the first rotation direction R1 with respect to the downstream contact surface 558 when viewed from the width direction D2, and the angle θB is 90 degrees or more.

The upstream shaft portion 123 presses the upstream contact surface 556 with a component force orthogonal to the upstream contact surface 556 of the tangential force PA, that is, a component force PAN of the tangential force PA in the oblique feed direction D4. The downstream shaft portion 124 presses the downstream contact surface 558 with a component force orthogonal to the upstream contact surface 556 of the tangential force PB, that is, a component force PBN of the tangential force PB in the oblique feed direction D4. Further, the upstream shaft portion 123 and the downstream shaft portion 124 receive normal force PAN', PBN' as a force having the same magnitude as the component force PAN, PBN'from the upstream side contact surface 556 and the downstream side contact surface 558. .. As a result, the upstream shaft portion 123 and the downstream shaft portion 124 are restricted from moving in the oblique feed direction D4.

However, a component force parallel to the upstream contact surface 556 of the tangential force PA and orthogonal to the oblique direction D3, that is, a component force PA of the tangential force PA in the orthogonal direction D5 acts on the nip NA in the roller portion 122. do. A component force of the tangential force PB parallel to the downstream contact surface 558 and orthogonal to the oblique direction D3, that is, a component force PBS of the tangential force PB in the orthogonal direction D5 acts on the nip NB in the roller portion 122. The component force PAS is an upward force that is a separation direction in which the oblique feed roller 120 is separated from the transport roller 110 when the angle θA is 90 degrees or less. Further, the component force PBS is a downward force in the approaching direction in which the oblique feed roller 120 approaches the transport roller 110 when the angle θB is 90 degrees or more.

The oblique feed roller 120 is basically arranged at a reference angle in which the rotating shaft 121 is parallel to the sheet transport plane. However, a force that rotates around the transport roller 110 acts on the oblique feed roller 120 due to the component force PAS and the component force PBS, and the downstream shaft portion 124 moves downward from the reference angle, that is, the first rotation. There is a risk of rotation in the direction R1. When the oblique feed roller 120 rotates from the reference angle in the first rotation direction R1, the center of the nip N1 moves toward the downstream shaft portion 124, so that the right nip NB becomes larger than the left nip NA, and the minute. Force PBS increases. As described above, in the roller portions 112 and 122, the nip N1 is biased to the right side, and uneven wear is likely to occur. Further, the component force PBS becomes a biting force as a force for the roller portion 122 to bite into the roller portion 112, and the pressing force of the roller portion 122 with respect to the roller portion 112 increases more than the urging force by the spring 130. As a result, the roller portions 112 and 122 may be more likely to be unevenly worn.

Further, since the downstream shaft portion 124 rotates in the second rotation direction R2, a frictional force PBμ with respect to the downstream contact surface 558 is generated as shown in FIG. Since the downstream shaft portion 124 rotates upward at the position where it comes into contact with the downstream contact surface 558, the frictional force PBμ is a downward force that hinders the operation of the downstream shaft portion 124. Therefore, a frictional force PBμ acts on the roller portion 122 in addition to the component force PBS as a biting force. The pressing force of the roller portion 122 against the roller portion 112 is further increased, and the roller portion 112 and the roller portion 122 are more likely to be unevenly worn.

When the friction coefficient between the downstream contact surface 558 and the downstream shaft portion 124 is μ, the friction force PBμ is obtained from the product of the friction coefficient μ and the component force PBN. The frictional force PBμ can be decomposed into a component force PB2 parallel to the tangential force PB, a component force PBμN orthogonal to the component force PB2, and a component force PB2 and a component force orthogonal to the component force PBμN (not shown). .. A component force PB2 acts on the roller portion 122 in addition to the tangential force PB in a direction parallel to the tangential force PB. Since the angle θB is 90 degrees or more and the frictional force PBμ acts downward in the direction parallel to the downstream contact surface 558, the frictional force PBμ becomes the tangential force PB when viewed from the width direction D2. On the other hand, it is inclined at an angle of 90 degrees or less in the first rotation direction R1. Therefore, the component force PB2 is a force in the same direction as the tangential force PB.

The component force PB2 is substantially the same as the tangential force PB, the component force PB2N (not shown) orthogonal to the downstream contact surface 558 and the component force PB2S parallel to the downstream contact surface 558 and orthogonal to the oblique direction D3. It can be decomposed into (not shown) and the component force in the oblique direction D3 (not shown). Then, a frictional force PBμ2 (not shown) corresponding to the component force PB2N acts on the downstream shaft portion 124. In the horizontal register correction unit 500, the component force PB2S and the frictional force PBμ2 are secondarily generated as the biting force by the frictional force PBμ as the biting force. By repeating this, the biting force becomes the resultant force of the inductively generated forces such as (PBS + PBμ) + (PB2S + PBμ2) + ...

The biting force becomes a predetermined value according to various parameters such as the friction coefficient. For example, when the tangential force PB is 500 gf, the angle θi of the sheet transport direction D1 with respect to the straight line L4 is 80 degrees, and the friction coefficient μ is 0.3, the biting force is calculated to be about 247 gf. Since the urging force against a general driven roller is 500 to 1000 gf, 247 gf is a value that cannot be ignored. As described above, the roller portion 112 and the roller portion 122 are more likely to be unevenly worn due to the biting force generated secondarily.

Since the resultant force of the forces parallel to the downstream contact surface 558 and orthogonal to the oblique direction D3 is released when the sheet S enters the nip N1, it may lead to a problem in a product having a relatively short product life. No. However, in the highly durable product, the roller portion 112 of the transport roller 110 and the roller portion 122 of the oblique feed roller 120 are gradually worn due to the intermittent rotation of the seat S without the seat S in the nip N1. go. The biting force is generated at the nip N1, and the center of the nip N1 moves downstream and to the right of the sheet transport direction D1 with respect to the axial intersection C1 when viewed from the orthogonal direction D5 as described above. Therefore, the roller portion 112 and the roller portion 122 become unevenly worn due to a large amount of wear at a position downstream and to the right of the sheet transport direction D1 with respect to the axial intersection C1 when viewed from the orthogonal direction D5, resulting in uneven feed roller. There is a risk that the oblique feeding force due to 120 will decrease. Due to the decrease in the oblique feeding force, the position correction by the horizontal register correction unit 500 is not properly performed, and there is a possibility that an image is formed at a position deviated from the sheet S when the image forming unit 30 forms an image.

[Detailed configuration of the first embodiment]
FIG. 3A is a view of the horizontal register correction unit 100 in the first embodiment viewed from the orthogonal direction D5, and FIG. 3B is a cross-sectional view taken along the line CC shown in FIG. 3A. 3 (c) is a cross-sectional view taken along the line DD shown in FIG. 3 (a). As shown in FIGS. 3 (a) to 3 (c), the horizontal register correction unit 100 slides the rotating shaft 121 so that the oblique feed roller 120 can rotate and can be brought into contact with and detached from the transport roller 110. It has a transport direction regulating unit 150 that supports it as possible. The transport direction regulating unit 150 is composed of transport direction regulating members 151 to 154 fixed to the printer main body 2. As shown in FIGS. 3 (b) and 3 (c), the transport direction regulating members 151 and 152 are arranged so as to sandwich the upstream shaft portion 123 from the upstream and downstream of the oblique feed direction D4. The transport direction regulating members 153 and 154 are arranged so as to sandwich the downstream shaft portion 124 from the upstream and downstream in the oblique feed direction D4.

Further, the transport direction regulating unit 150 has a contact surface 155 as a first support surface that abuts and supports the rotating shaft 121. The contact surface 155 includes an upstream contact surface 156 as a first upstream support surface, an upstream contact surface 157, a downstream contact surface 158 as a downstream support surface, and a downstream contact surface 159. And is composed of. The upstream side contact surface 156 is provided on the transport direction regulating member 151 and abuts on the downstream side of the oblique feed direction D4 on the upstream shaft portion 123, and the upstream side contact surface 157 is provided on the transport direction regulating member 152. It comes into contact with the upstream of the oblique feed direction D4 in the upstream shaft portion 123. The downstream contact surface 158 is provided on the transport direction regulating member 153 and abuts on the downstream side of the oblique feed direction D4 on the downstream shaft portion 124, and the downstream contact surface 159 is provided on the transport direction regulating member 154. It comes into contact with the upstream of the oblique feed direction D4 in the downstream shaft portion 124.

The upstream contact surface 156 is provided parallel to the upstream contact surface 157, and is arranged at an angle inclined in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2. As described above, the straight line L3 is inclined in the direction opposite to the first rotation direction R1 with respect to the orthogonal direction D5. Therefore, the upstream contact surface 156 is arranged at an angle inclined in the first rotation direction R1 with respect to the straight line L3. The tangential force PA faces a direction inclined by an angle θA in the first rotation direction R1 with respect to the upstream contact surface 156 when viewed from the width direction D2, and the angle θA is 90 degrees or less. The angle θA in the horizontal register correction unit 100 of the first embodiment is smaller than the angle θA in the horizontal register correction unit 500 of the comparative example.

The downstream contact surface 158 is provided parallel to the downstream contact surface 159, and is arranged at an angle inclined in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2. For example, when viewed from the width direction D2, the tangential force PB may be inclined by the maximum angle θBmax in the first rotation direction R1 with respect to the sheet transport direction D1. In this case, the downstream contact surface 158 is arranged at an angle inclined by an angle θBmax or more in the first rotation direction R1 with respect to the orthogonal direction D5.

Further, since the straight line L4 is orthogonal to the tangential force PB, the straight line L4 is inclined at an angle θBmax in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2. Since the downstream contact surface 158 is arranged at the above-mentioned angle, it is arranged at an angle inclined in the first rotation direction R1 with respect to the straight line L4 when viewed from the width direction D2. Therefore, the tangential force PB faces a direction inclined by an angle θB in the first rotation direction R1 with respect to the downstream contact surface 158 when viewed from the width direction D2, and the angle θB is 90 degrees or less. The downstream contact surface 158 is arranged at an angle inclined in the first rotation direction R1 with respect to the upstream contact surface 156, and the inclination angle with respect to the orthogonal direction D5 is larger than that with the upstream contact surface 156. It is formed to be.

Since it is configured as described above, the oblique feed roller 120 receives a tangential force PB facing downward from the sheet transport direction D1 as shown in FIG. 3 (c). Since the angle θB is 90 degrees or less, the frictional force PBμ is inclined by 90 degrees or more in the first rotation direction R1 with respect to the tangential force PB when viewed from the width direction D2. As a result, the direction of the component force PB2 included in the frictional force PBμ becomes the direction opposite to the tangential force PB.

Further, since the angle θR is 90 degrees or less, the component force PBS parallel to the downstream contact surface 158 and orthogonal to the oblique direction D3 of the tangential force PB faces upward. A force is applied to the oblique feed roller 120 so that the downstream shaft portion 124 moves upward by the component force PBS and rotates in the direction opposite to the first rotation direction R1. As a result, the oblique feed roller 120 is prevented from rotating in the first rotation direction R1 from the reference angle.

Further, as shown in FIG. 3B, the oblique feed roller 120 receives a tangential force PA facing upward from the sheet transport direction D1 when viewed from the width direction D2. Since the angle θA is 90 degrees or less, the frictional force PAμ is inclined by 90 degrees or more in the first rotation direction R1 with respect to the tangential force PA when viewed from the width direction D2. As a result, the direction of the component force PA2 included in the frictional force PAμ becomes the direction opposite to the tangential force PA.

Further, since the angle θA is 90 degrees or less, the component force PAS parallel to the upstream contact surface 156 and orthogonal to the oblique direction D3 of the tangential force PA faces upward. A force is applied to the oblique feed roller 120 so that the upstream shaft portion 123 moves upward by the component force PAS and rotates in the first rotation direction R1. The diagonal feed roller 120 is given a force to rotate in the direction opposite to the first rotation direction R1 by the component force PBS, but is given a force to rotate in the first rotation direction R1 by the component force PAS. Therefore, rotation from the reference angle in the direction opposite to the first rotation direction R1 is suppressed. As described above, the tangential force PA and the tangential force PB included in the tangential force P1 act on the oblique feed roller 120 by the contact surface 155 so that the rotating shaft 121 is parallel to the sheet transport plane, and the oblique feed roller 120. The rotation of 120 from the reference angle is suppressed.

Further, the component force PAS increases as the angle θA decreases, and the component force PBS also increases as the angle θB decreases, based on the trigonometric function. In the lateral register correction unit 100, the downstream contact surface 158 is formed so that the inclination angle with respect to the orthogonal direction D5 is larger than that of the upstream contact surface 156, so that the angle θA is not significantly smaller than the angle θB. It is configured as follows. As a result, the lateral register correction unit 100 prevents the component force PAS from becoming a significantly large force with respect to the component force PBS, and the oblique feed roller 120 is rotated from the reference angle in the first rotation direction R1 by the component force PAS. Suppress that.

Further, even if the rotation shaft 121 is rotated from the reference angle in the first rotation direction R1, the downstream shaft portion 124 is moved upward by the component force PBS, so that the rotation shaft 121 is in the direction opposite to the first rotation direction R1. It rotates and returns to the reference angle. Further, even if the rotation shaft 121 rotates in the direction opposite to the first rotation direction R1 from the reference angle, the upstream shaft portion 123 moves upward by the component force PAS, so that the rotation shaft 121 moves to the first rotation direction R1. It rotates and returns to the reference angle.

As described above, in the lateral register correction unit 100, since the component force PAS and the component force PBS face upward, it is possible to prevent the biting force, that is, the pressing force of the roller portion 122 with respect to the roller portion 112 from increasing. Further, in the lateral register correction unit 100, since the directions of the component force PA2 and the component force PB2 are opposite to the directions of the tangential force PA and the tangential force PB, it is possible to prevent the biting force from increasing in a recursive manner. .. Further, the lateral register correction unit 100 suppresses the oblique feed roller 120 from rotating from the reference angle, and even if it rotates from the reference angle, it returns to the reference angle, so that the reference angle can be maintained. As a result, in the lateral register correction unit 100, it is possible to prevent the center of the nip N1 from deviating from the axial intersection C1 when viewed from the orthogonal direction D5, so that the roller portion 112 and the roller portion 122 can be prevented from being unevenly worn. Can be done.

<Second embodiment>
Subsequently, the second embodiment will be described. In addition, about the same structure as the 1st Embodiment, the illustration is omitted, or the same reference numerals are given to the drawings, and the description thereof will be omitted. As shown in FIG. 1, the printer 1A includes a horizontal register correction unit 100A as a sheet transfer device that corrects a position in the width direction D2. FIG. 4 (a) is a view of the lateral register correction unit 100A viewed from the orthogonal direction D5, and FIG. 4 (b) is a cross-sectional view taken along the line CC shown in FIG. 4 (a). c) is a cross-sectional view taken along the line DD shown in FIG. 4 (a).

As shown in FIGS. 4 (a) to 4 (c), the horizontal register correction unit 100A has a transport direction regulating unit 150A that slidably supports the rotating shaft 121. The transport direction regulating unit 150A is composed of transport direction regulating members 151A to 154A fixed to the printer main body 2. The transport direction regulating members 151A to 154A each have two types of contact surfaces arranged side by side in the orthogonal direction D5. The transport direction regulating unit 150A has a contact surface 155A as a support surface that abuts and supports the rotating shaft 121, and a contact surface 200 as an orthogonal support surface arranged above the contact surface 155A. ing.

The contact surface 155A includes an upstream contact surface 156A as a first upstream support surface, an upstream contact surface 157A, a downstream contact surface 158A as a downstream support surface, and a downstream contact surface 159A. And, it is composed of. Further, the contact surface 200 includes an upstream contact surface 201 as an upstream orthogonal support surface, an upstream contact surface 202, a downstream contact surface 203 as a downstream orthogonal support surface, and a downstream contact surface. It is composed of a surface 204 and. The upstream contact surfaces 156A and 201 are provided on the transport direction regulating member 151A, and the upstream contact surfaces 157A and 202 are provided on the transport direction regulating member 152A. Further, the downstream contact surfaces 158A and 203 are provided on the transport direction regulating member 153A, and the downstream contact surfaces 159A and 204 are provided on the transport direction regulating member 154A.

The upstream contact surface 156A is arranged in parallel with the upstream contact surface 157A, and is located in the orthogonal direction D5 when viewed from the width direction D2, substantially like the upstream contact surface 156 in the first embodiment. On the other hand, it is arranged at an angle inclined in the first rotation direction R1. The tangential force PA faces a direction inclined by an angle θA in the first rotation direction R1 with respect to the upstream contact surface 156A when viewed from the width direction D2, and the angle θA is 90 degrees or less. The upstream contact surface 201 is continuously formed at the upper end of the upstream contact surface 156A, and the upstream contact surface 202 is continuously formed at the upper end of the upstream contact surface 157A. That is, the upstream contact surface 201 is continuous with the downstream end of the upstream contact surface 156A in the separation direction, and the upstream contact surface 202 is continuous with the downstream end of the upstream contact surface 157A in the separation direction.

The downstream contact surface 158A is arranged in parallel with the downstream contact surface 159A, and is inclined in the first rotation direction R1 with respect to the straight line L4, substantially similar to the downstream contact surface 158 in the first embodiment. It is arranged at the right angle. The tangential force PB faces a direction inclined by an angle θB in the first rotation direction R1 with respect to the downstream contact surface 158A when viewed from the width direction D2, and the angle θB is 90 degrees or less. The downstream contact surface 203 is continuously formed at the upper end of the downstream contact surface 158A, and the downstream contact surface 204 is continuously formed at the upper end of the downstream contact surface 159A. That is, the downstream contact surface 203 is continuous with the downstream end of the downstream contact surface 158A in the separation direction, and the downstream contact surface 204 is continuous with the downstream end of the downstream contact surface 159A in the separation direction.

The upstream contact surfaces 201 and 202 and the downstream contact surfaces 203 and 204 are arranged parallel to the oblique direction D3 and the orthogonal direction D5, respectively. Therefore, the tangential force PA is inclined in the first rotation direction R1 with respect to the upstream contact surfaces 201 and 202 at an angle larger than the angle θA when viewed from the width direction D2. Further, the tangential force PB is inclined at an angle of 90 degrees or more in the first rotation direction R1 with respect to the downstream contact surfaces 203 and 204.

The upstream contact surfaces 156A and 157A and the downstream contact surfaces 158A and 159A are in the orthogonal direction D5 when the oblique feed roller 120 is located at a reference angle and the roller portion 122 is in contact with the roller portion 112. Is arranged at a position where the rotating shaft 121 abuts. Further, the upstream contact surfaces 201 and 202 and the downstream contact surfaces 203 and 204 are arranged at positions where the rotating shaft 121 abuts in the orthogonal direction D5 when the sheet S enters the nip N1. There is.

Since it is configured as described above, the horizontal register correction unit 100A uses the diagonal feed roller 120 as a reference in substantially the same manner as the horizontal register correction unit 100 of the first embodiment in a state where the sheet S has not been conveyed. Can be kept at an angle. As a result, in the lateral register correction unit 100A, it is possible to prevent the center of the nip N1 from deviating from the axial intersection C1 when viewed from the orthogonal direction D5, so that the roller portion 112 and the roller portion 122 can be prevented from being unevenly worn. Can be done.

Further, for example, when the component force PBS becomes larger than the component force PAS and the oblique feed roller 120 rotates in the direction opposite to the first rotation direction R1 from the reference angle, the downstream shaft portion 124 is on the downstream side. It comes into contact with the contact surface 203. Since the tangential force PB is inclined with respect to the downstream contact surface 203 at an angle of 90 degrees or more in the first rotation direction R1, the component force PBS faces downward. As a result, the oblique feed roller 120 rotates in the first rotation direction R1 and returns to the reference angle.

Further, for example, when the component force PAS becomes larger than the component force PBS and the oblique feed roller 120 rotates from the reference angle in the first rotation direction R1, the upstream shaft portion 123 becomes the upstream side contact surface 201. Contact. Since the tangential force PA is inclined in the first rotation direction R1 with respect to the upstream contact surface 201 at an angle larger than the angle θA, the component force PA becomes smaller. As a result, the oblique feed roller 120 rotates in the direction opposite to the first rotation direction R1 and returns to the reference angle. In the lateral register correction unit 100A, the oblique feed roller 120 can be maintained at a reference angle, and uneven wear of the roller portion 112 and the roller portion 122 can be prevented.

Further, when the sheet S enters the nip N1, the oblique feed roller 120 moves upward by the thickness of the sheet S, as shown in FIGS. 5A and 5B. As a result, the rotating shaft 121 moves to a position where it abuts on the upstream contact surfaces 201 and 202 and the downstream contact surfaces 203 and 204. Further, the upstream contact surfaces 201 and 202 and the downstream contact surfaces 203 and 204 are parallel to the orthogonal direction D5. As a result, even if the oblique feed roller 120 moves along the upstream contact surfaces 201 and 202 and the downstream contact surfaces 203 and 204, the angle with respect to the transport roller 110 as viewed from the orthogonal direction D5 does not change. It is held at an angle θs. The lateral register correction unit 100A can prevent the direction of the oblique feeding force by the oblique feeding roller 120 from changing according to the thickness of the sheet S when the sheet S is conveyed.

<Third embodiment>
Subsequently, the third embodiment will be described. In addition, about the same structure as the 1st Embodiment, the illustration is omitted, or the same reference numerals are given to the drawings, and the description thereof will be omitted. As shown in FIG. 1, the printer 1B includes a horizontal register correction unit 100B as a sheet transfer device that corrects a position in the width direction D2. FIG. 6A is a view of the lateral register correction unit 100B viewed from the orthogonal direction D5, and FIG. 6B is a cross-sectional view taken along the line CC shown in FIG. 6A. As shown in FIGS. 6 (a) and 6 (b), the lateral register correction unit 100B has a transport direction regulating unit 150B that slidably supports the rotating shaft 121. The transport direction regulating unit 150B is composed of transport direction regulating members 151B, 152B, 153, 154 fixed to the printer main body 2.

Further, the transport direction regulating unit 150B has a contact surface 155B as a support surface that abuts and supports the rotating shaft 121. The contact surface 155B is composed of an upstream contact surface 156B as a second upstream support surface, an upstream contact surface 157B, and downstream contact surfaces 158 and 159. The upstream side contact surface 156B is provided on the transport direction regulating member 151B, and the upstream side contact surface 157B is provided on the transport direction regulating member 152B.

The upstream contact surface 156B is provided in parallel with the upstream contact surface 157B, and is inclined at an angle opposite to the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2. Have been placed. For example, when viewed from the width direction D2, the tangential force PA may be inclined by the maximum angle θAmax in the direction opposite to the first rotation direction R1 with respect to the sheet transport direction D1. In this case, the upstream contact surface 156B is arranged at an angle inclined by the angle θAmax or more in the direction opposite to the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2.

Further, since the straight line L3 is orthogonal to the tangential force PA, the straight line L3 is inclined at an angle θAmax in the direction opposite to the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2. Since the upstream side contact surface 156B is arranged at the above-mentioned angle, it is arranged at an angle inclined in the direction opposite to the first rotation direction R1 with respect to the straight line L3 when viewed from the width direction D2. Therefore, the tangential force PA faces a direction inclined by an angle θA in the first rotation direction R1 with respect to the upstream contact surface 156B when viewed from the width direction D2, and the angle θA is 90 degrees or more.

Since it is configured as described above, the oblique feed roller 120 receives a tangential force PA facing upward from the sheet transport direction D1 as shown in FIG. 5 (b). Since the angle θA is 90 degrees or more, the component force PAS parallel to the upstream contact surface 157B and orthogonal to the oblique direction D3 of the tangential force PA faces downward. A force is applied to the oblique feed roller 120 in which the upstream shaft portion 123 moves downward due to the component force PAS and rotates in a direction opposite to the first rotation direction R1. As a result, the oblique feed roller 120 is suppressed from rotating in the first rotation direction R1 from the reference angle, and is suppressed from rotating from the reference angle. In the lateral register correction unit 100B, it is possible to prevent the center of the nip N1 from deviating from the axial intersection C1 when viewed from the orthogonal direction D5, so that the roller portion 112 and the roller portion 122 can be prevented from being unevenly worn.

<Fourth Embodiment>
Subsequently, the fourth embodiment will be described. In addition, about the same structure as the 1st Embodiment, the illustration is omitted, or the same reference numerals are given to the drawings, and the description thereof will be omitted. As shown in FIG. 1, the printer 1C includes a sheet transfer device 100C downstream of the double-sided transfer roller pair 83 in the sheet transfer direction. FIG. 7A is a view of the sheet transport device 100C viewed from the orthogonal direction D5, and FIG. 7B is an arrow view of the sheet S viewed from the arrow E shown in FIG. 7A. As shown in FIG. 7, the sheet transport device 100C includes a transport roller 110C as a third rotating body and a diagonal feeding roller 120C as a fourth rotating body, together with a transport roller 110, a diagonal feed roller 120, and a sheet transport path 84. doing. The diagonal feed roller 120 is urged toward the transport roller 110 by a spring 130, substantially like the diagonal feed roller 120 of the first embodiment, and is urged toward the transport roller 110 by the transport direction regulating unit 150 shown in FIG. 3 (a). It is rotatably supported by the transport roller 110 so as to be contactable and detachable.

The transfer roller 110C and the oblique transfer roller 120C are arranged on the right side of the transfer roller 110 and the oblique transfer roller 120, and the transfer roller 110 and the oblique transfer roller 120 are arranged with respect to the central CS in the width direction D2 of the sheet transfer path 84. It is configured to be symmetrical. The transport roller 110C includes a rotating shaft 111C as a third rotating shaft that is supported by the printer main body 2 and extends in the width direction D2, and a roller portion 112C that is provided on the outer periphery of the rotating shaft 111C and comes into contact with the oblique feed roller 120C. ,have. The rotating shaft 111C is arranged symmetrically with respect to the central CS with respect to the rotating shaft 111, and is composed of one rotating shaft together with the rotating shaft 111.

The oblique feed roller 120C includes a rotating shaft 121C as a fourth rotating shaft that is swingably supported in the direction D5 orthogonal to the printer main body 2, and a roller portion of the conveying roller 110C provided on the outer periphery of the rotating shaft 121C. It has a roller portion 122C that comes into contact with the 112C. The rotation axis 121C is arranged symmetrically with respect to the center CS when viewed from the orthogonal direction D5. Further, a spring 130C as a second urging portion for urging toward the roller portion 112C is fixed to the rotating shaft 121C. The roller portion 122C presses the roller portion 112C by the urging force of the spring 130C.

The axis L5 as the rotation center of the rotation shaft 121C is basically arranged parallel to the axis L1 when viewed from the sheet transfer direction D1 and is parallel to the sheet transfer plane. However, the axis L5 intersects the width direction D2 and the oblique direction D3 when viewed from above, and extends in the oblique direction D6 as a direction symmetrical to the oblique direction D3 with respect to the central CS. In the fourth embodiment, the axis L2 is inclined by an angle θs counterclockwise with respect to the axis L1 as viewed from FIG. 7 (a), and the axis L5 is inclined with respect to the axis L1 from FIG. 7 (a). The angle θs is tilted clockwise when viewed. Therefore, the upstream shaft portion 123C of the rotating shaft 121C is arranged on the right side in the width direction D2, and the downstream shaft portion 124C of the rotating shaft 121C is arranged on the left side in the width direction D2.

8 (a) is a view of the sheet transport device 100C viewed from the orthogonal direction D5, and FIG. 8 (b) is a cross-sectional view taken along the line CC shown in FIG. 8 (a), FIG. 8 (c). ) Is a cross-sectional view taken along the line DD shown in FIG. 8 (a). As shown in FIGS. 8A to 8C, the transport roller 110C can rotate in the first rotation direction R1 about the rotation shaft 111C. The oblique feed roller 120C has a rotation shaft 121C extending in the oblique feed direction D6 so as to convey the sheet S in the oblique feed direction D7 which is orthogonal to the oblique feed direction D6 and faces to the right of the sheet transport direction D1. It can rotate in the forward rotation direction R3 at the center. The roller portion 122C is arranged so as to come into contact with the roller portion 112C at the axis intersection C2 where the axis L1 and the axis L5 intersect when viewed from the orthogonal direction D5. That is, the nip N2 as the second nip formed by the roller portion 122C in contact with the roller portion 112C is formed centering on the axial intersection C2 when viewed from the orthogonal direction D5.

The rotation shaft 111C is driven and rotated in the first rotation direction R1 by the driving force of the motor M. When the transport roller 110C is driven and rotated in the first rotation direction R1 while being in contact with the oblique feed roller 120C, the roller portion 122C has a second acting force in the direction in which the roller portion 122C rotates in the forward rotation direction R3. The tangential force P3 of is acting. Due to the action and reaction, the tangential force P4, which has the same magnitude as the tangential force P3 but acts in the opposite direction, acts on the roller portion 112C as a load on the driving force of the motor M. Since the tangential force P3 and the tangential force P4 are the forces acting on the nip N2, they are the tangential directions of the roller portion 112C and the roller portion 122C on the nip N2 and are the forces parallel to the sheet transport plane. The oblique feed roller 120C is driven to rotate in the forward rotation direction R3 by the tangential force P3.

When the sheet S is conveyed to the nip N2, the friction between the transfer roller 110C and the sheet S gives the sheet S a transfer force in the sheet transfer direction D1 from the transfer roller 110C driven by the motor M. The oblique feed roller 120C rotates in the forward rotation direction R3, and the friction between the oblique feed roller 120C and the sheet S imparts a conveying force in the oblique feed direction D7 to the sheet S. In the following, the conveying force applied to the sheet S from the oblique feeding roller 120C in the oblique feeding direction D7 is also referred to as the oblique feeding force. The diagonal feeding force applied to the sheet S of the diagonal feeding roller 120 and the diagonal feeding roller 120C is directed in a direction away from each other with respect to the central CS.

Further, the sheet transport device 100C has axial direction regulating portions 125C and 126C having a shape fixed to the printer main body 2 and extending in the orthogonal direction D5 on both sides of the rotating shaft 121C of the oblique feed roller 120C in the oblique direction D6. have. The sheet transport device 100C has a transport direction regulation unit 150C arranged between the axial regulation units 125C and 126C in the oblique direction D6. The transport direction regulating unit 150C is arranged symmetrically with respect to the center CS with the transport direction regulating unit 150, and is composed of the transport direction regulating members 151C to 154C corresponding to the transport direction regulating members 151 to 154. As shown in FIGS. 8 (b) and 8 (c), the transport direction regulating members 151C and 152C are arranged so as to sandwich the upstream shaft portion 123C from the upstream and the downstream in the oblique feed direction D7. The transport direction regulating members 153C and 154C are arranged so as to sandwich the downstream shaft portion 124C from the upstream and the downstream in the oblique feed direction D7.

Further, the transport direction regulating unit 150C has a contact surface 155C as a second support surface that abuts and supports the rotating shaft 121C. The contact surface 155C is arranged symmetrically with respect to the center CS and corresponds to the upstream contact surface 156, 157 and the downstream contact surfaces 158, 159. It is composed of 157C and downstream contact surfaces 158C and 159C.

By the way, the nip N2 is formed in the vicinity of the axial intersection C2 centered on the axial intersection C2 when viewed from the orthogonal direction D5, substantially like the nip N1. The tangential force P3 is the resultant force of the tangential force PC, which is the resultant force of the forces dispersed on the upstream shaft portion 123C side of the axial intersection C2 in the oblique direction D6, and the resultant force of the forces distributed on the downstream shaft portion 124C side. It can be decomposed into the tangential force PD. The tangential force PC is a force acting on the upstream shaft portion 123C, and the tangential force PD is a force acting on the downstream shaft portion 124C.

In the right nip NC as a region of the nip N2 on the upstream side of the axis intersection C2 on the upstream shaft portion 123C, the central CNC is located upstream of the axis L1 in the sheet transport direction D1 when viewed from the orthogonal direction D5. The tangential force PC is a force orthogonal to the straight line L6 connecting the axis L1 and the center CNC of the right nip NC and the axis L5. Since the straight line L6 is inclined in the direction opposite to the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2, the tangential force PC is above the sheet transport plane, that is, the tangential force P3. It is a force that faces.

Further, in the left nip ND as a region of the nip N2 on the side of the downstream shaft portion 124C from the axis intersection C2, the central CND is located downstream of the sheet transport direction D1 when viewed from the orthogonal direction D5. The tangential force PD is a force orthogonal to the straight line L7 connecting the axis L1 and the center CND of the left nip ND and the axis L5. Since the straight line L7 is inclined in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2, the tangential force PD is a force downward from the tangential force P3.

The upstream contact surface 156C is provided parallel to the upstream contact surface 157C, and is arranged at an angle inclined in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2. As described above, the straight line L6 is inclined in the direction opposite to the first rotation direction R1 with respect to the orthogonal direction D5. Therefore, the upstream contact surface 156C is arranged at an angle inclined in the first rotation direction R1 with respect to the straight line L6. The tangential force PC faces a direction inclined by an angle θC in the first rotation direction R1 with respect to the upstream contact surface 156C when viewed from the width direction D2, and the angle θC is 90 degrees or less.

The downstream contact surface 158C is provided parallel to the downstream contact surface 159C, and is arranged at an angle inclined in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2. For example, when viewed from the width direction D2, the tangential force PD may be inclined by the maximum angle θDmax in the first rotation direction R1 with respect to the sheet transport direction D1. In this case, the downstream contact surface 158C is arranged at an angle inclined by an angle θDmax or more in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2.

Further, since the straight line L7 is orthogonal to the tangential force PD, the straight line L7 is inclined at an angle θDmax in the first rotation direction R1 with respect to the orthogonal direction D5 when viewed from the width direction D2. Since the downstream contact surface 158C is arranged at the above-mentioned angle, it is arranged at an angle inclined in the first rotation direction R1 with respect to the straight line L7 when viewed from the width direction D2. Therefore, the tangential force PD faces a direction inclined by an angle θD in the first rotation direction R1 with respect to the downstream contact surface 158C when viewed from the width direction D2, and the angle θD is 90 degrees or less. The downstream contact surface 158C is arranged at an angle inclined in the first rotation direction R1 with respect to the upstream contact surface 156C, and the inclination angle with respect to the orthogonal direction D5 is larger than that with the upstream contact surface 156C. It is formed to be.

Since it is configured as described above, in substantially the same manner as the tangential force P1, the tangential force PC and the tangential force PD included in the tangential force P3 have the rotation shaft 121C parallel to the sheet transport plane due to the contact surface 155C. As such, it acts on the oblique feed roller 120C. As a result, the sheet transport device 100C can prevent the diagonal feed roller 120C from rotating from the reference angle together with the diagonal feed roller 120. The sheet transport device 100C can prevent the center of the nip N1 from deviating from the axial intersection C1 and prevent the center of the nip N2 from deviating from the axial intersection C2 when viewed from the orthogonal direction D5. The sheet transfer device 100C can prevent the roller portions 112, 122, 112C, 122C from being unevenly worn.

Further, as shown in FIGS. 7 (a) and 7 (b), the sheet transport device 100C moves the sheet S transported by the diagonal feed force of the diagonal feed roller 120 and the diagonal feed roller 120C to the width direction D2. The sheet is conveyed in the sheet conveying direction D1 while being extended toward the outside. For example, the sheet S may be heated and pressurized by the fixing portion 50 to generate undulations 300. However, in the sheet transport device 100C, the waviness 300 can be eliminated by the diagonal feeding force of the diagonal feeding roller 120 and the diagonal feeding roller 120C, and the image formed by the image forming unit 30 can be prevented from being displaced.

In the horizontal register correction units 100 to 100B and the sheet transfer device 100C in the first to fourth embodiments, the transfer rollers 110 and 110C are driven and rotated by the motor M, and the oblique feed rollers 120 and 120C are driven and rotated. It is configured, but not limited to this. The sheet transfer device may be configured such that the oblique feed rollers 120 and 120C are driven and rotated by the motor M, and the transfer rollers 110 and 110C are driven and rotated.

In this case, the tangential force acting on the oblique feed rollers 120 and 120C from the transport rollers 110 and 110C is a force in the opposite direction to the tangential forces P1 and P3, which is substantially the same as the tangential forces P2 and P4. That is, the tangential forces PA', PB', PC', PD'in the directions opposite to those of the tangential forces PA, PB, PC and PD act on the oblique feed rollers 120 and 120C. In this case, the upstream contact surfaces and the downstream contact surfaces on the contact surfaces 155, 155A, 155B, and 155C are opposite to the directions in the first to fourth embodiments with respect to the orthogonal direction D5. Tilt in the direction. As a result, the tangential forces PA', PB', PC', PD'act on the diagonal feed rollers 120, 120C so that the rotating shafts 121, 121C are parallel to the sheet transport plane, and the roller portions 112, 122, It is possible to prevent the 112C and 122C from being unevenly worn.

Further, in the horizontal register correction units 100 to 100B and the sheet transfer device 100C in the first to fourth embodiments, the oblique feed rollers 120 and 120C are configured to be urged by the springs 130 and 130C. Not limited to. The sheet transfer device may be configured such that the transfer rollers 110 and 110C are urged toward the oblique feed rollers 120 and 120C by the urging portion. In the sheet transfer device, the first rotating shaft of the first rotating body and the third rotating shaft of the third rotating body extend in the oblique directions D3 and D6, and are urged to the first urging portion and the third urging portion. The second rotation axis of the second rotating body and the fourth rotation axis of the fourth rotating body may be configured to extend in the width direction D2. Further, the sheet transfer device may be configured so that all of the first rotation axis to the fourth rotation axis extend in a direction intersecting the width direction D2 when viewed from the orthogonal direction D5.

Further, in the horizontal register correction units 100 to 100B and the sheet transfer device 100C of the first to fourth embodiments, the upstream contact surfaces 156 to 156C, 157 to 157C and the downstream contact surfaces 158, 158A, 158C, 159, It has 159A and 159C, but is not limited to this. The sheet transfer device may be configured to have an upstream contact surface parallel to the orthogonal direction D5 and a downstream contact surface 158, 158A, 158C, 159, 159A, 159C. Further, the sheet transfer device may be configured to have upstream contact surfaces 156B and 157B and downstream contact surfaces parallel to the orthogonal direction D5.

Further, in the horizontal register correction units 100 to 100B and the sheet transfer device 100C in the first to fourth embodiments, the oblique feed rollers 120 and 120C are urged toward the transfer roller 110 by the spring 130. Not exclusively. The sheet transfer device may be configured such that the oblique feed rollers 120 and 120C are urged by an elastic member such as rubber. Further, the sheet transfer device may be configured such that the oblique feed rollers 120 and 120C are urged toward the transfer roller 110 by their own weight, and the oblique feed rollers 120 and 120C themselves also serve as an urging portion.

Further, the horizontal register correction units 100 to 100B and the sheet transfer device 100C in the first to fourth embodiments are configured to convey the sheet S transferred from the fixing unit 50 to the image forming unit 30. , Not limited to this. The sheet transport device may be configured to transport the sheet S fed from the feed cassette 10 to the image forming unit 30. Further, the sheet transport device may be configured to transport the sheet S discharged from the fixing unit 50 to the discharge roller pair 60. Further, the sheet transfer device may be arranged instead of the discharge roller pair 60.

Further, the horizontal register correction units 100 to 100B in the first to third embodiments are configured to have the horizontal register reference unit 140, but the present invention is not limited to this. Since the seat transport device does not have the lateral register reference unit 140, the seat transport device may be configured to apply an oblique feeding force to the seat S without correcting the position of the seat S in the width direction D2.

Further, in the horizontal register correction units 100, 100A and the sheet transfer device 100C in the first, second and fourth embodiments, the upstream contact surface and the downstream contact surface on the contact surfaces 155, 155A, 155C are formed. They are arranged at different angles, but are not limited to this. The sheet transfer device may be configured so that the first upstream support surface and the downstream support surface on the support surface are arranged in parallel.

Further, in the horizontal register correction unit 100A in the second embodiment, the upstream contact surfaces 201 and 202 and the downstream contact surfaces 203 and 204 are provided in parallel with the orthogonal direction D5, but the present invention is not limited to this. The sheet transfer device may be configured such that the upstream contact surfaces 201 and 202 and the downstream contact surfaces 203 and 204 are inclined with respect to the orthogonal direction D5. In this case, the angle of the rotating shaft 121 with respect to the rotating shaft 111 when viewed from the orthogonal direction D5 can be changed according to the thickness of the sheet S.

1,1A, 1B, 1C: Image forming device (printer), 30: Image forming unit, 100, 100A, 100B: Sheet transfer device (horizontal register correction unit), 100C: Sheet transfer device, 110: First rotating body ( Conveying roller), 110C: 3rd rotating body (conveying roller), 111: 1st rotating shaft (rotating shaft), 111C: 3rd rotating shaft (rotating shaft), 120: 2nd rotating body (diagonal feeding roller), 120C : 4th rotating body (diagonal feed roller), 121: 2nd rotating shaft (rotating shaft), 121C: 4th rotating shaft (rotating shaft), 123, 123C: upstream shaft, 124, 124C: downstream shaft, 130 : Biasing part (first urging part, spring), 130C: Second urging part (spring), 141: Seat regulation surface (reference surface), 155: Support surface (first support surface, contact surface), 155C: 2nd support surface (contact surface), 156, 156A, 156C: 1st upstream support surface (upstream contact surface), 156B: 2nd upstream support surface (upstream contact surface), 158, 158A, 158C: Downstream support surface (downstream contact surface), 201: Upstream orthogonal support surface (upstream contact surface), 203: Downstream orthogonal support surface (downstream contact surface), D1: Third Direction (sheet transport direction), D2: 1st direction (width direction), D3: 2nd direction (oblique direction), D5: orthogonal direction, D6: 4th direction (oblique direction), N1: nip (1st) Nip), N2: 2nd nip, P1: Acting force (1st acting force, tangential force), P2: 2nd acting force (tangential force)

Claims (9)

A first rotating body that rotates about a first rotation axis extending in the first direction and applies a conveying force to the seat in a third direction orthogonal to the first direction.
The nip is formed by abutting on the first rotating body, and the first direction is viewed from an orthogonal direction parallel to the first direction and the third direction and orthogonal to a predetermined plane along the sheet conveying path. A second rotating body that rotates about a second rotating axis extending in a second direction intersecting with the first rotating body and conveys a sheet together with the first rotating body at the nip.
An urging portion that urges the second rotating body toward the first rotating body, and
The drive source that drives the first rotating body and
It is provided with a support surface that slidably supports the second rotating shaft so that the second rotating body can rotate and can be brought into contact with and separated from the first rotating body.
The second rotation shaft has a downstream shaft portion located on one of the nips in the second direction and on the downstream side in the third direction.
The support surface has a downstream support surface that slidably supports the downstream shaft portion.
The downstream support surface is oriented in the orthogonal direction from the upstream side to the downstream side in the third direction so that the second rotating body is separated from the first rotating body in the orthogonal direction. Tilt,
The support surface is the second rotating body so that the tangential force of the nip acting on the second rotating body from the first rotating body is parallel to the predetermined plane. provided al is as act, and inclined with respect to the perpendicular direction with respect to,
The downstream support surface is formed so that the direction of the component force parallel to the downstream support surface of the acting force faces the downstream side in the separation direction.
A sheet transfer device characterized by this. A downstream orthogonal support surface that is continuous with the downstream end of the downstream support surface in the separation direction and extends in parallel with the orthogonal direction is provided.
The sheet transport device according to claim 1. The second rotation shaft has an upstream shaft portion located on the other side of the nip in the second direction and on the upstream side in the third direction.
The support surface has a first upstream support surface that slidably supports the upstream shaft portion.
The first upstream support surface is inclined in the separation direction from the upstream side to the downstream side in the third direction with respect to the orthogonal direction.
The sheet transport device according to claim 1 or 2 , wherein the sheet transport device is characterized by the above. The first upstream support surface is formed so that the direction of the component force parallel to the first upstream support surface of the acting force is directed to the downstream in the separation direction.
The sheet transport device according to claim 3 , wherein the sheet transport device is characterized by this. An upstream orthogonal support surface that is continuous with the downstream end of the first upstream support surface in the separation direction and extends in parallel with the orthogonal direction is provided.
The sheet transport device according to claim 3 or 4. The downstream support surface is arranged so that the inclination angle with respect to the orthogonal direction is larger than that of the first upstream support surface.
The sheet transport device according to any one of claims 3 to 5 , wherein the sheet transport device is characterized by this. The first direction is the width direction of the sheet conveyed by the first rotating body and the second rotating body.
It is provided with a sheet regulating surface that abuts on the side portion in the width direction of the sheet conveyed by the first rotating body and the second rotating body and regulates the position of the side portion.
The sheet transport device according to any one of claims 1 to 6 , wherein the sheet transport device is characterized by this. The first direction is the width direction of the sheet conveyed by the first rotating body and the second rotating body.
The nip, the acting force, the urging portion and the supporting surface are the first nip, the first acting force, the first urging portion and the first supporting surface, respectively.
A sheet transport path for guiding the sheet transported by the first rotating body and the second rotating body, and
A third rotating body that is arranged symmetrically with respect to the center of the sheet transport path in the width direction and rotates about a third rotating axis extending in the first direction.
A fourth rotation that abuts on the third rotating body to form a second nip and is arranged symmetrically with respect to the center of the sheet transport path in the width direction when viewed from the orthogonal direction. A fourth rotating body that rotates about a shaft and conveys a sheet together with the third rotating body at the second nip, and a fourth rotating body.
A second urging portion that urges the fourth rotating body toward the third rotating body, and
It is provided with a second support surface that slidably supports the fourth rotating shaft so that the fourth rotating body can rotate and can be brought into contact with and separated from the third rotating body.
In the second support surface, the second acting force in the tangential direction at the second nip acting on the fourth rotating body from the third rotating body is such that the fourth rotating axis is parallel to the predetermined plane. Is provided so as to act on the fourth rotating body and be inclined with respect to the orthogonal direction.
The directions of the conveying forces applied to the seats of the second rotating body and the fourth rotating body are oriented away from each other with respect to the center of the sheet conveying path in the width direction.
The sheet transport device according to any one of claims 1 to 7 , wherein the sheet transport device is characterized by this. The sheet transfer device according to any one of claims 1 to 8.
An image forming unit for forming an image on a sheet conveyed from the sheet conveying device is provided.
An image forming apparatus characterized in that.

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