JP6972610B2 - Sheet supply device and image forming device - Google Patents

Description

The present invention relates to a sheet feeder and an image forming apparatus.

In an image forming apparatus such as a printer or a copier, a sheet such as printing paper is conveyed along a transport path from a paper feed tray to a paper discharge tray, and the sheet being conveyed is conveyed by an image forming unit provided in the middle of the transport path. An image is formed in.

On the upper side of the paper feed tray, a paper feed roller and a separation roller are provided side by side in this order in the sheet transport direction. A separation pad is in contact with the peripheral surface of the separation roller from below. When supplying the sheet, the paper feed roller and the separation roller are started to rotate while the paper feed roller is pressed against the sheet on the paper feed tray. The rotation of the paper feed roller causes the sheet to be fed from the paper feed tray toward the transport path. Then, the sent out sheets are separated one by one between the separation roller and the separation pad, and one sheet passes between the separation roller and the separation pad and is supplied to the transport path.

Japanese Unexamined Patent Publication No. 2012-166931

In such a configuration, when the sheet passing between the separation roller and the separation pad receives the transfer force from the transfer roller pair provided in the transfer path on the downstream side in the sheet transfer direction from the separation roller, the nip of the separation roller and the separation pad is received. Tension is applied to the sheet between the position and the transfer roller pair, and there is a possibility that abnormal noise may be generated due to the sheet being pressed against the edge of the separation pad on the downstream side in the sheet transfer direction and rubbing.

An object of the present invention is to provide a sheet supply device and an image forming device capable of suppressing the generation of abnormal noise due to rubbing between a sheet and a separation pad.

In order to achieve the above object, the sheet supply device and the image forming device according to the present invention include a roller (36) for transporting a sheet, a separation pad (37) arranged to face the peripheral surface of the roller (36), and a separation pad (37). The separation pad (37) is provided with a holder (111) for holding the separation pad (37), and the separation pad (37) has a recess (102) recessed from the downstream side to the upstream side in the transfer direction at the end portion on the downstream side in the transfer direction of the sheet. The holder (111) is fitted in the recess (102), and the sheet conveyed by the roller (36) is placed in the first position (N1) lower than the nip position (N1) between the separation pad (37) and the roller (36). It has a guide portion that guides from P1) to a second position (P2) higher than the nip position (N1).

According to this configuration, the sheets are conveyed by receiving a conveying force from the peripheral surface of the roller, and are separated one by one between the peripheral surface of the roller and the facing surface of the separation pad facing the peripheral surface. It is supplied from between the roller and the separation pad to the downstream side in the transport direction.

The separation pad has a recess recessed from the downstream side to the upstream side in the transport direction at the end portion on the downstream side in the transport direction. Therefore, the edge on the downstream side in the transport direction of the facing surface is partially missing, and the length of the edge is the dimension in the width direction (direction orthogonal to both the transport direction and the thickness direction) of the separation pad. Smaller than. Therefore, even if the sheet rubs against the edge of the separation pad, the abnormal noise generated by the rubbing can be suppressed to a small level.

The holder is provided with a guide portion that fits into the recess of the separation pad. The guide portion is formed so as to guide the sheet transported to the downstream side in the transport direction from a position lower than the nip position of the separation roller and the separation pad to a position higher than the nip position. Since the sheet is guided by the guide portion and the sheet is lifted to a position higher than the nip position of the separation pad, the sheet is suppressed from rubbing against the edge of the separation pad, so that abnormal noise due to the rubbing between the sheet and the edge is suppressed. Can be suppressed.

According to the present invention, it is possible to suppress the sheet from rubbing against the downstream edge of the separation pad, and it is possible to suppress the generation of abnormal noise due to the rubbing between the sheet and the downstream edge.

It is sectional drawing of the laser printer which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure in the vicinity of a separation roller and a separation pad. It is a perspective view of a separation pad and a holder, and shows the state which a separation pad is held in a holder. It is an exploded perspective view of a separation pad and a holder, and shows the state which the separation pad was removed from a holder. It is a top view of a separation pad and a holder. It is sectional drawing of the separation pad and a holder in the cutting plane line AA shown in FIG. It is sectional drawing of the separation pad and a holder in the cutting plane line BB shown in FIG. It is a figure which shows the 1st modification of the shape of the separation pad. It is a figure which shows the 2nd modification of the shape of the separation pad. It is a figure which shows the 3rd modification of the shape of the separation pad. It is a figure which shows the 4th modification of the shape of the separation pad. It is a figure which shows the 5th modification of the shape of the separation pad.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Overall configuration of laser printer>
The laser printer 1 (an example of an image forming apparatus) shown in FIG. 1 is a monochrome laser printer.

The laser printer 1 includes a housing 11 having a substantially rectangular parallelepiped shape.

A paper feed tray 21 is provided on the bottom of the housing 11 so that it can be inserted and removed. The paper feed tray 21 is configured to be able to support a plurality of sheets S such as printing paper in a stacked state.

For use in the following description, the side on which the paper feed tray 21 is inserted / removed from the housing 11 is defined as the "front side" of the laser printer 1, and the opposite side is defined as the "rear side". Then, the "upper side", "lower side", "left side", and "right side" of the laser printer 1 are defined with reference to the state in which the laser printer 1 is viewed from the "front side".

A first paper feed mechanism 22 is provided on the upper side of the front end portion of the paper feed tray 21. The first paper feed mechanism 22 includes a paper feed roller 23, a separation roller 24, and a separation pad 25.

The paper feed roller 23 is provided so as to be rotatable about an axis extending in the left-right direction. With the paper feed tray 21 mounted at the mounting position in the housing 11, the peripheral surface of the paper feed roller 23 comes into contact with the upper surface of the front end portion of the uppermost sheet S housed in the paper feed tray 21.

The separation roller 24 is arranged on the front side of the paper feed roller 23 and is rotatably provided about an axis extending in the left-right direction.

The separation pad 25 comes into contact with the peripheral surface of the separation roller 24 from the front lower side in a state where the paper feed tray 21 is mounted at the mounting position in the housing 11.

The housing 11 has a non-used position in which the multi-purpose tray 31 extends vertically along the front surface 12 of the housing 11 and a used position in which the multi-purpose tray 31 lays down forward from the non-used position and extends in an upwardly inclined manner (FIG. 1). It is provided so that it can be displaced at the position shown). The multi-purpose tray 31 is configured to be supportable in a state where a plurality of sheets S are stacked at the position of use. Further, when the multi-purpose tray 31 is located at the used position, the paper feed port 32 that communicates with the inside and outside of the housing 11 is opened.

A second paper feed mechanism 33 (an example of a sheet supply device, an example of a sheet supply unit) is provided on the back side (rear side) of the paper feed port 32. As shown in FIGS. 1 and 2, the second paper feed mechanism 33 includes a paper feed pad 34, a paper feed roller 35, a separation roller 36, and a separation pad 37.

The paper feed pad 34 is arranged behind the lower end of the paper feed port 32.

The paper feed roller 35 is arranged above the paper feed pad 34 and is rotatably provided about an axis extending in the left-right direction. The sheet S supported by the multi-purpose tray 31 straddles the multi-purpose tray 31 and the paper feed pad 34, and the peripheral surface of the paper feed roller 35 contacts the upper surface of the front end portion of the uppermost sheet S.

The separation roller 36 is arranged behind the paper feed roller 35 and is rotatably provided about an axis extending in the left-right direction.

The separation pad 37 is in contact with the peripheral surface of the separation roller 36 from the rear side, and the separation roller 36 and the separation pad 37 form a nip between them.

A photoconductor drum 41 (an example of an image forming portion) is arranged in the center of the housing 11. The photoconductor drum 41 is provided so as to be rotatable about an axis extending in the left-right direction.

A charger 42 (an example of an image forming unit), a transfer roller 43 (an example of an image forming unit), and a developer 44 (an example of an image forming unit) are arranged around the photoconductor drum 41.

The charger 42 is arranged on the rear upper side of the photoconductor drum 41. The charger 42 is, for example, a scorotron type charger including wires and a grid.

The transfer roller 43 is arranged to face the photoconductor drum 41 on the lower side and is rotatably provided about an axis extending in the left-right direction.

The developer 44 is arranged on the front side of the photoconductor drum 41. The developer 44 includes a developing housing 45 for accommodating toner, a developing roller 46 held in the developing housing 45, and the like. The developing roller 46 is provided so as to be rotatable about an axis extending in the left-right direction. The peripheral surface of the developing roller 46 is in contact with the peripheral surface of the photoconductor drum 41.

An exposure device 47 (an example of an image forming unit) is arranged in the housing 11 at a position above the charger 42. The exposure device 47 includes an optical system such as a laser and a polygon mirror, and emits a laser beam based on image data. The laser beam is applied to the peripheral surface of the photoconductor drum 41 through between the charger 42 and the developer 44.

Further, in the housing 11, a fixing device 51 (an example of an image forming portion) is arranged on the rear side of the photoconductor drum 41. The fuser 51 includes a thermal roller 52 and a compression roller 53. The thermal roller 52 is provided so as to be rotatable about an axis extending in the left-right direction. The compression roller 53 is arranged on the rear lower side of the thermal roller 52 and is rotatably provided about an axis extending in the left-right direction. The peripheral surface of the compression roller 53 is in contact with the peripheral surface of the thermal roller 52.

Further, a resist roller pair 61 (an example of a transport roller pair), a paper ejection roller set 62, a first transport roller pair 63, and a second transport roller pair 64 are provided in the housing 11.

The resist roller pair 61 is arranged on the front side of the photoconductor drum 41 and the transfer roller 43. A predetermined distance is provided between the photoconductor drum 41 and the transfer roller 43 and the resist roller pair 61.

The resist roller pair 61 includes a pair of drive rollers 71 and a driven roller 72. The peripheral surface of the driven roller 72 is in contact with the peripheral surface of the drive roller 71 from the rear upper side. As a result, the resist roller pair 61 forms a nip between the drive roller 71 and the driven roller 72. This nip is located at a position lower than the nip position N1 between the separation roller 36 and the separation pad 37. Therefore, the nip position N2 of the resist roller pair 61 is higher than the position P2 of the edge of the second inclined surface 133, which will be described later. Further, the tangent line T in contact with both the drive roller 71 and the driven roller 72 at the nip position N2 is inclined downward with a downward slope, and a part of the separation roller 36 is located below the tangent line T. There is.

A paper output tray 14 is formed on the upper surface 13 of the housing 11 as a part of the upper surface 13. Further, the housing 11 is formed with a wall surface 15 extending upward from the rear end of the paper output tray 14. On the wall surface 15, a paper ejection port 16 for ejecting the sheet S to the paper ejection tray 14 is formed at a position spaced upward from the rear end of the paper ejection tray 14. The paper ejection roller set 62 is arranged on the rear side of the paper ejection port 16. The paper ejection roller set 62 includes a drive roller 73 and two driven rollers 74 and 75. The drive roller 73 and the driven rollers 74 and 75 are provided so as to be rotatable around an axis extending in the left-right direction in a state where the peripheral surfaces are in contact with each other.

The first transport roller pair 63 is arranged on the front upper side of the first paper feed mechanism 22. The first transfer roller pair 63 includes a pair of drive rollers 76 and a driven roller 77. The drive roller 76 and the driven roller 77 are provided so as to be rotatable about an axis extending in the width direction in a state where the peripheral surfaces are in contact with each other.

The second transport roller pair 64 is arranged at a position on the rear upper side of the fuser 51 and on the rear lower side of the paper ejection roller assembly 62. The second transfer roller pair 64 includes a pair of drive rollers 78 and a driven roller 79. The drive roller 78 and the driven roller 79 are provided so as to be rotatable about an axis extending in the width direction in a state where the peripheral surfaces are in contact with each other.

A first transport path 91, a second transport path 92 (an example of a transport path), a third transport path 93, and a fourth transport path 94 are provided in the housing 11.

The first transport path 91 is curved in a U shape from between the separation roller 24 and the separation pad 25 to the rear upper side via between the first transport roller pair 63.

The second transfer path 92 extends rearward from the first transfer path 91, and is between the nip of the resist roller pair 61, between the photoconductor drum 41 and the transfer roller 43, and the heat roller 52 and the pressure roller 53 of the fuser 51. It goes through in this order.

The third transport path 93 extends from the second transport path 92 to the rear upper side, curves in a U shape to the front upper side via between the first transport roller pairs 63, and passes between the paper ejection roller sets 62. It has reached the paper ejection port 16.

The fourth transport path 94 extends rearward from the paper feed port 32 and passes through the nip between the paper feed pad 34 and the paper feed roller 35 and between the separation roller 36 and the separation pad 37 in this order. 2 Joins the transport path 92 from the front side.

<Laser printer operation>
At the time of printing on the sheet S (image formation), the sheet S is sent out from the paper feed tray 21 or the multipurpose tray 31.

When the sheet S is fed out from the paper feed tray 21, the paper feed roller 23 of the first paper feed mechanism 22 is rotated counterclockwise when viewed from the left side. Due to the rotation of the paper feed roller 23, the sheet S in contact with the peripheral surface of the paper feed roller 23 is fed forward. The sheet S sent out from the paper feed tray 21 is separated one by one by passing between the separation roller 24 and the separation pad 25, and enters the first transport path 91.

The sheet S that has entered the first transport path 91 receives a transport force from the first transport roller pair 63 and advances through the first transport pass 91. Since the first transport path 91 is curved in a U shape, the seat S traveling on the first transport path 91 makes a U-turn to the front side and enters the second transport path 92. The sheet S that has entered the second transport path 92 advances to the rear side of the second transport pass 92.

When the sheet S is fed out from the multi-purpose tray 31, the paper feed roller 35 of the second paper feed mechanism 33 is rotated counterclockwise when viewed from the left side. The rotation of the paper feed roller 35 causes the sheet S in contact with the peripheral surface of the paper feed roller 35 to be fed forward. The sheets S sent out from the multi-purpose tray 31 are separated one by one by passing through the nip between the separation roller 36 and the separation pad 37. The seat S passing through the nip advances along the fourth transport path 94 toward the second transport path 92 and enters the second transport path 92. The sheet S that has entered the second transport path 92 advances to the rear side of the second transport pass 92.

On the other hand, the photoconductor drum 41 is rotated clockwise when viewed from the left side. As the photoconductor drum 41 rotates, the surface of the photoconductor drum 41 is uniformly charged by the discharge from the charger 42, and then selectively exposed by the laser beam from the exposure device 47. By this exposure, electric charges are selectively removed from the surface of the photoconductor drum 41, and an electrostatic latent image is formed on the surface of the photoconductor drum 41. The electrostatic latent image is developed into a toner image by supplying toner from the developing roller 46.

The formation of the toner image and the feeding of the sheet S are performed in synchronization, and the timing at which the sheet S is interposed between the photoconductor drum 41 and the transfer roller 43 when the toner image faces the transfer roller 43. Then, the rotation of the resist roller pair 61 is started. A transfer bias is supplied to the transfer roller 43. When the sheet S passes between the photoconductor drum 41 and the transfer roller 43, the toner image is transferred from the surface of the photoconductor drum 41 to the upper surface of the sheet S by the action of the transfer bias.

The sheet S on which the toner image is transferred further advances to the rear side of the second transport path 92 and enters the fuser 51. In the fuser 51, the sheet S passes between the thermal roller 52 and the compression roller 53. At that time, the toner image is fixed to the sheet S by heating and pressurizing. As a result, the formation of an image on the sheet S is achieved. The sheet S on which the image is formed enters the third transport path 93 from the second transport path 92.

The sheet S that has entered the third transport path 93 receives a transport force from the second transport roller pair 64 and advances through the third transport pass 93 toward the paper ejection roller set 62. Then, the sheet S receives a conveying force from the paper ejection roller assembly 62 toward the paper ejection tray 14 side, and is ejected from the paper ejection port 16 onto the paper ejection tray 14.

<Separation pad>
As shown in FIGS. 3 and 4, the separation pad 37 of the second paper feed mechanism 33 has a substantially rectangular plate shape that is longer in the left-right direction than the transport direction of the sheet S.

The left-right direction coincides with the width direction of the separation pad 37. The width direction of the separation pad 37 is the transport direction of the sheet S at the nip position N1 between the separation roller 36 and the separation pad 37 (hereinafter, simply referred to as “transport direction”) and the thickness direction of the separation pad 37 (hereinafter, simply “thickness”). It is a direction orthogonal to both of the directions.

The separation pad 37 has a recess 102 recessed from the downstream side in the transport direction to the upstream side at the end portion 101 on the downstream side in the transport direction. The recess 102 is recessed in a rectangular shape long in the left-right direction, and is formed symmetrically with respect to a straight line extending in the transport direction through the center of the separation pad 37 in the left-right direction.

In other words, the separation pad 37 has two convex portions 103 and 104 protruding toward the downstream side in the transport direction, respectively, at the end portion 101 on the downstream side in the transport direction. The convex portions 103 and 104 are each formed in a long rectangular shape in the left-right direction, are separated from each other in the left-right direction, and are symmetrical with respect to a straight line extending in the transport direction through the center of the separation pad 37 in the left-right direction. Is doing.

Since the separation pad 37 has the recess 102, the edge 105 on the downstream side in the transport direction of the surface (upper surface) of the separation pad 37 facing the separation roller 36 is partially missing in the center in the left-right direction. Therefore, the total length of the edges 105 in the left-right direction is smaller than the total width dimension of the separation pad 37.

<Holder>
The separation pad 37 is held by a resin holder 111.

As shown in FIG. 4, the holder 111 integrally includes a holder support portion 112 and a holder main body portion 113 supported by the holder support portion 112.

The holder support portion 112 has a substantially rectangular plate shape extending in the transport direction and the left-right direction. Support shaft portions 122 and 123 projecting to the left and right sides are formed at the end portion 121 on the upstream side of the holder support portion 112 in the transport direction.

A pad arrangement portion 124 having a substantially rectangular concave shape is formed in the holder main body portion 113. Specifically, the holder main body 113 has a substantially rectangular bottom plate portion 125, an upstream side wall portion 126 that protrudes upward from the bottom plate portion 125 and extends along the end edge of the bottom plate portion 125 on the upstream side in the transport direction, and upstream. A downstream side wall portion 127 that faces the side wall portion 126 in the transport direction and extends along the edge of the bottom plate portion 125 on the downstream side in the transport direction, and a bottom plate portion 125 that protrudes from the bottom plate portion 125 toward the separation roller 36 (see FIG. 2). It has a left side wall portion 128 extending along the left edge of the bottom plate portion 128, and a right side wall portion 129 facing the left side wall portion 128 in the left-right direction and extending along the right side edge of the bottom plate portion 125. The pad arrangement portion 124 is formed as a recess on the upper side of the bottom plate portion 125, which is surrounded by the upstream side wall portion 126, the downstream side wall portion 127, the left side wall portion 128, and the right side wall portion 129.

As shown in FIGS. 3 and 5, the separation pad 37 is held in the holder 111 in a state of being arranged in the pad arrangement portion 124. The holder 111 is provided so as to be swingable with the support shaft portions 122 and 123 as fulcrums by rotatably holding the support shaft portions 122 and 123 to the frame F (see FIG. 2) in the housing 11. Then, the holder main body 113 is pressed toward the separation roller 36 by the urging force of an urging member (not shown) such as a coil spring, so that the separation pad 37 elastically abuts on the separation roller 36 and nips. To form.

As shown in FIGS. 6 and 7, the upstream side wall portion 126 projects toward the separation roller 36 with respect to the upper surface (contact surface with the sheet S) of the separation pad 37 arranged in the pad arrangement portion 124. ..

Therefore, when the sheet S is conveyed toward the nip of the separation roller 36 and the separation pad 37, the tip of the sheet S does not collide with the end surface on the upstream side in the transfer direction of the separation pad 37, and the tip of the sheet S does not collide. Moves smoothly onto the separation pad 37.

The downstream side wall portion 127 also protrudes toward the separation roller 36 with respect to the upper surface of the separation pad 37 arranged in the pad arrangement portion 114. Further, in the central portion in the left-right direction of the downstream side wall portion 127, a protruding portion 131 projecting from the side surface of the downstream side wall portion 127 on the upstream side in the transport direction to the upstream side in the transport direction is integrally formed. As shown in FIG. 5, the protrusion 131 is formed in a shape that fits into the recess 102 of the separation pad 37. Further, as shown in FIG. 6, the projecting portion 131 has a first inclined surface 132 that is inclined so as to approach the bottom plate portion 125 toward the upstream side in the transport direction from the upper end of the downstream side wall portion 127. The edge of the first inclined surface 132 on the upstream side in the transport direction is located at a position P0 lower in the thickness direction than the nip position N1 between the separation roller 36 and the separation pad 37. Further, as shown in FIG. 7, a second inclined surface 133 inclined so as to approach the bottom plate portion 125 toward the upstream side in the transport direction is formed at the upper end portion of the downstream side wall portion 127. As can be seen by comparing FIGS. 6 and 7, the second inclined surface 133 has a larger inclination than the first inclined surface 132. In other words, the first inclined surface 132 has a smaller (slower) slope than the second inclined surface 133.

The tip of the sheet S that has passed through the nip of the separation roller 36 and the separation pad 37 hangs down by its own weight immediately after passing through the edge 105 of the separation pad 37, and is at a position P1 lower in the thickness direction than the edge 105 (an example of the first position). ), It comes into contact with the first inclined surface 132, goes up the first inclined surface 132, further moves from the first inclined surface 132 to the second inclined surface 133, goes up the second inclined surface 133, and goes up the second inclined surface 133. Reach the position P2 (an example of the second position and the fourth position) of the edge on the downstream side in the transport direction. As a result, the tip of the sheet S is located at a position P1 closer to the thickness direction than the edge 105 of the separation pad 37 by the first inclined surface 132 and the second inclined surface 133, in other words, the nip between the separation roller 36 and the separation pad 37. It is guided from the position P1 lower in the thickness direction than the position N1 to the highest position P2 in the thickness direction on the second inclined surface 133. Therefore, it can be said that the protruding portion 131 having the first inclined surface 132 and the downstream side wall portion 127 having the second inclined surface 133 constitute a guide portion 134 that guides the seat S from the position P1 to the position P2.

When the tip of the sheet S exceeds the position P2 (an example of the second position and the fourth position) of the edge on the downstream side in the transport direction of the second inclined surface 133, the tip of the sheet S becomes as shown in FIG. , Straddles between the downstream side wall portion 127 and the separation pad 37, and rises from the edge 105 of the separation pad 37.

<Second guide section>
As shown in FIG. 2, a second guide portion 141 for guiding the seat S is provided on the rear side of the holder 111. The second guide portion 141 is integrally formed with the frame F, and is located between a position spaced rearward and lower and a position spaced rearward and upper with respect to the nip of the separation roller 36 and the separation pad 37. , Has an arc-shaped curved cross-sectional shape that bulges toward the separation roller 36 side (front upper side). Therefore, the rear end edge (end edge on the downstream side in the transport direction) on the surface of the second guide portion 141 on the side of the separation roller 36 is larger than the position P2 of the edge on the downstream side in the transport direction of the second inclined surface 133 of the holder 111. It is located at the upper position P3 (an example of the third position) in the vertical direction. The downstream side wall portion 127 constituting the guide portion 134 projects toward the separation roller 36 side with respect to the straight line L connecting the position P3, the separation roller 36, and the nip position N1 of the separation pad 37.

<Action effect>
As described above, the sheet S is conveyed by receiving a conveying force from the peripheral surface of the separation roller 36, and is conveyed one by one between the peripheral surface of the separation roller 36 and the facing surface of the separation pad 37 facing the peripheral surface. It is separated into and supplied from between the separation roller 36 and the separation pad 37 to the downstream side in the transport direction.

The separation pad 37 has a recess 102 recessed from the downstream side in the transport direction to the upstream side at the end portion 101 on the downstream side in the transport direction. Therefore, the edge 105 of the separation pad 37 is partially missing, and the total length of the edges 105 in the left-right direction is smaller than the total width dimension of the separation pad 37. Therefore, even if the sheet S rubs against the edge 105, the abnormal noise generated by the rubbing can be suppressed to a small level.

The holder 111 is provided with a guide portion 134 that fits into the recess 102 of the separation pad 37. The guide portion 134 is formed so as to guide the sheet S transported downstream in the transport direction from a position P1 lower than the nip position N1 of the separation roller 36 and the separation pad 37 to a position P2 higher than the nip position N1. Since the seat S is guided by the guide portion 134 and the seat S is lifted, the seat S is suppressed from rubbing against the edge 105 of the separation pad 37, so that an abnormal noise is generated due to the rubbing between the seat S and the edge 105. Can be suppressed.

The guide portion 134 has a first inclined surface 132 and a second inclined surface 133 arranged on the downstream side in the transport direction with respect to the first inclined surface 132. The slope of the first inclined surface 132 is gentler than that of the second inclined surface 133. Therefore, the sheet S whose tip is in contact with the first inclined surface 132 can be gently lifted.

The recess 102 of the separation pad 37 is formed symmetrically with respect to a straight line extending in the transport direction through the center of the separation pad 37 in the left-right direction. Therefore, the resistance received by the sheet S from the separation pad 37 is less likely to be different between the left and right sides, and the sheet S can be conveyed satisfactorily.

A second guide portion 141 for guiding the seat S is provided on the downstream side of the holder 111 in the transport direction. The guide portion 134 projects toward the separation roller 36 with respect to the straight line L connecting the nip position N1 and the position P3 which is the highest position in the second guide portion 141. Therefore, the sheet S enters between the drive roller 71 and the driven roller 72 of the resist roller pair 61 and straddles between the resist roller pair 61 and the nip position N1 from the resist roller pair 61. When the conveying force is applied to S, the separation pad 37 is pushed down by the tension generated in the sheet S. As a result, it is possible to suppress the generation of sound due to the sheet S being strongly rubbed against the separation roller 36 after the rotation of the separation roller 36 is stopped.

<Modification example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, in the above-described embodiment, a rectangular recess 102 that is long in the left-right direction is formed at the end 101 on the downstream side in the transport direction of the separation pad 37, and a protrusion 131 that fits into the recess 102 is formed in the guide portion 134. I picked up the composition that is. Not limited to this, the relationship between the unevenness of the separation pad 37 and the guide portion 134 may be reversed, or the shapes of the concave portion 102 and the protruding portion 131 may be changed.

To give some specific examples, the shape of the recess 102 may be a triangular shape that narrows from the downstream side in the transport direction to the upstream side, as shown in FIG.

Further, as shown in FIG. 9, the separation pad 37 may be formed with a rectangular convex portion 151 projecting from the upstream side to the downstream side in the transport direction on the protruding portion 131. In this case, it is preferable that the guide portion 134 is formed with a concave portion into which the convex portion 151 is fitted, and the first inclined surface 132 is formed on both the left and right sides of the concave portion.

As shown in FIG. 10, the shape of the convex portion 151 may be a triangular shape that narrows from the upstream side to the downstream side in the transport direction.

Further, as shown in FIG. 11, rectangular concave portions 102 and convex portions 151 may be formed alternately in the left-right direction on the separation pad 37, or as shown in FIG. 12, the separation pad may be formed. In 37, triangular concave portions 102 and convex portions 151 may be formed alternately side by side in the left-right direction.

As an example of the image forming apparatus, the laser printer 1 is taken up. However, the present invention can be widely applied not only to the laser printer 1 but also to other types of image forming apparatus such as an inkjet printer. Further, the present invention can be applied not only to an image forming apparatus but also to an image reading apparatus for reading an image of a sheet.

In addition, various design changes can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1: Laser printer 33: Second paper feed mechanism 36: Separation roller 37: Separation pad 41: Photoreceptor drum 42: Charger 43: Transfer roller 44: Developer 47: Exposed device 51: Fixer 61: Resist roller vs. 92 : Second transport path 101: End 102: Recess 105: Edge 111: Holder 127: Downstream side wall 131: Protruding 132: First inclined surface 133: Second inclined surface 134: Guide part 141: Second guide part L : Straight line N1, N2: Nip position P1, P2, P3: Position S: Sheet

Claims (9)

Rollers that transport the sheet and
Separation pads arranged facing the peripheral surface of the roller from below,
A holder for holding the separation pad is provided.
The separation pad has a recess recessed from the downstream side to the upstream side in the transport direction at the end portion on the downstream side in the transport direction of the sheet.
The holder fits in the recess and moves the sheet conveyed by the roller from a first position lower than the upper surface of the separation pad to a second position higher than the upper surface of the separation pad in the thickness direction of the separation pad. A seat supply device having a guide portion for guiding. The sheet supply device according to claim 1.
The holder, the provided downstream end in the transport direction, and a downstream wall extending in the widthwise direction perpendicular to both the conveying direction and the thickness direction, said from the upstream side of the conveyance direction of the downstream wall It has a protruding portion that protrudes upstream in the transport direction , and has a protruding portion.
The protrusion fits into the recess and
The guide portion includes a first inclined surface formed as the upper surface of the projecting portion is formed in an upper end portion of the downstream wall portion, which is disposed downstream of the conveying direction with respect to the first inclined surface It has a second inclined surface and
The first inclined surface has a gentler slope than the second inclined surface, and is a sheet feeding device. The sheet supply device according to claim 1 or 2.
The separation pad is a sheet feeding device in which the recess is formed so as to have a symmetrical shape in a width direction orthogonal to both the transport direction and the thickness direction of the separation pad. The sheet supply device according to any one of claims 1 to 3.
It is provided on the downstream side of the holder in the transport direction and is provided with a second guide portion for guiding the seat.
The guide portion protrudes toward the roller with respect to a straight line connecting the nip position between the separation pad and the roller and the third position highest in the thickness direction of the separation pad in the second guide portion. Feeder. The sheet supply device according to claim 4.
The third position of the second guide portion is located above the fourth position, which is the highest in the thickness direction of the separation pad in the guide portion, in the vertical direction. The sheet supply device according to any one of claims 1 to 5.
The separation pad is a sheet feeding device having the recess in the center in the width direction orthogonal to both the transport direction and the thickness direction of the separation pad. A sheet supply unit that supplies sheets to the transport path,
An image forming unit for forming an image on the sheet supplied to the transport path is provided.
The sheet supply unit is an image forming device, which is the sheet supply device according to any one of claims 1 to 6. A sheet supply unit that supplies sheets to the transport path,
A transport roller pair provided on the transport path and transporting a sheet supplied by the sheet supply unit, and a transport roller pair.
An image forming unit for forming an image on a sheet transported through the transport path is provided.
The sheet supply unit is the sheet supply device according to claim 4.
The transport roller pair is an image forming apparatus in which a second nip position formed by the transport roller pair is arranged so as to be located below the third position of the second guide portion in the vertical direction. The image forming apparatus according to claim 8.
The transport roller pair is an image forming apparatus in which the second nip position formed by the transport roller pair is arranged so as to be located below the guide portion in the vertical direction.

Images