JP2014015316A - Sheet feeder and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable, in a sheet feeder including a first loading unit, a second loading unit, and a conveyance chute and an image forming apparatus, sheets loaded on the second loading unit to be satisfactorily fed out.SOLUTION: A first loading unit 100 includes a pressing plate 110 that can be displaced between a separation position and an approach position, and a sheet 99 is loaded on the pressing plate 110. A second loading unit 200 is positioned above the first loading unit 100, and the other sheet 99 is loaded thereon. A conveyance chute 50 is positioned on the downstream side of a feeding roller 11 in a feeding direction D1, and guides the sheet 99 to be fed out. The feeding roller 11 is displaced from the separation position to the approach position of the pressing plate 110, to feed out the sheet 99 loaded on the first loading unit 100 or the second loading unit 200 toward a conveyance path P1. A downstream end 110D of the pressing plate 110 and an upstream end 50U of the conveyance chute 50 respectively include comb-tooth portions 300L and 300R, which engage with each other in a comb-tooth shape, with at least the pressing plate 110 being at the separation position.

Description

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

  Patent Document 1 discloses an example of a conventional sheet supply apparatus. The sheet supply apparatus includes a conveyance path through which a sheet is conveyed and a delivery roller that sends the sheet to the conveyance path.

  In addition, the sheet supply device includes a pressure plate, and includes a first placement unit on which a sheet sent to the conveyance path is placed on the pressure plate. The pressure plate is displaceable between a separation position that is spaced downward with respect to the delivery roller and an approach position that rises from the separation position and approaches the delivery roller.

  Further, the sheet supply device is located above the first placement unit, and is downstream of the second placement unit on which another sheet to be sent out to the conveyance path is placed, and the sending roller in the sending direction in which the sheet is sent out. And a transport chute located on the side. The conveyance chute comes into contact with the fed sheet from below and guides the sheet to be conveyed along the conveyance path.

  In this sheet supply apparatus, the pressure plate is displaced from the separation position to the approach position, so that the feeding roller comes into contact with the sheet placed on the first placement section or the second placement section, and sends the sheet to the conveyance path. .

Japanese Utility Model Publication No. 4-12425

  By the way, in the conventional sheet feeding apparatus, a gap between the downstream end portion in the feeding direction of the pressure plate and the upstream end portion in the feeding direction of the conveyance chute extends linearly in the width direction of the sheet. For this reason, when a sheet is placed on the second placement portion in a state where no sheet is placed on the first placement portion, the downstream end of the pressure plate at the separated position and the upstream side of the conveyance chute There is a possibility that the leading edge of the sheet placed on the second placement portion enters the gap with the end portion. Then, when the pressure plate is displaced to the approaching position and the feeding roller feeds the sheet placed on the second placing portion, the sheet is jammed with its leading edge entering the gap, and the sheet is sent out satisfactorily. Is difficult.

  The present invention has been made in view of the above-described conventional situation, and is a sheet supply device and an image forming apparatus that include a first placement portion, a second placement portion, and a conveyance chute. It is an object of the present invention to be able to satisfactorily send out a sheet placed on the sheet.

The sheet supply apparatus of the present invention includes a conveyance path through which a sheet is conveyed,
A delivery roller for feeding the sheet to the transport path;
The sheet having a pressure plate that is displaceable between a separation position that is spaced downward with respect to the delivery roller and an approach position that is raised from the separation position and approaches the delivery roller, and is sent to the conveyance path A first placement portion placed on the pressure plate;
A second placement unit that is located on the upper side of the first placement unit and on which the other sheet sent to the transport path is placed;
A transport chute that is positioned downstream of the transport roller in the transport direction in which the sheet is transported, contacts the transported sheet from below, and guides the sheet to be transported along the transport path. ,
The feeding roller abuts on the sheet placed on the first placement portion or the second placement portion when the pressure plate is displaced from the separation position to the approach position, and conveys the sheet. To the route,
The downstream end of the pressure plate in the delivery direction and the upstream end of the transport chute in the delivery direction are comb teeth that mesh with each other in a comb shape with at least the pressure plate in the spaced position. It is characterized by having.

  In the sheet feeding apparatus of the present invention, the gap between the downstream end portion in the feeding direction of the pressure plate and the upstream end portion in the feeding direction of the conveying chute engages with each other in a comb-tooth shape at least in a state where the pressure plate is in the separated position. It is divided by the comb teeth and does not extend linearly in the width direction of the sheet. For this reason, even when the sheet is placed on the second placement portion in a state where the sheet is not placed on the first placement portion, the gap placed by the comb teeth portion is not in the second placement portion. The leading edge of the placed sheet does not enter. For this reason, when the pressure plate is displaced to the approaching position and the feeding roller feeds the sheet placed on the second placement portion, it is difficult to cause a problem that the leading end of the sheet enters the gap and becomes clogged.

  Therefore, in the sheet supply apparatus of the present invention, the sheet placed on the second placement unit can be sent out satisfactorily. Further, when the comb teeth mesh with each other even when the pressure plate is in the approach position, the leading edge of the sheet fed from the second placement portion advances while coming into contact with the comb teeth, so that the sheet is pressed against the pressure plate. Is successfully delivered to the transport chute.

  It is desirable that the comb-tooth portion is provided at a position where it can come into contact with the tip of the minimum width sheet placed on the second placement portion. In this case, since the comb tooth portion acts on all the sheets placed on the second placement portion as described above, the sheets can be sent out satisfactorily.

  The sheet supply apparatus of the present invention preferably includes a separation pad that is provided on the conveyance chute and separates the sheets sent to the conveyance path one by one. And it is desirable for the comb tooth part to be located in at least two places sandwiching the separation pad from the width direction of the sheet. In this case, the sheet placed on the second placement portion can be sent out satisfactorily while reducing the number of places where the comb teeth portion is installed.

  The second mounting portion is a first guide portion that extends from the upstream side to the downstream side in the delivery direction, and a second guide portion that is positioned downstream from the first guide portion in the delivery direction and bends downward from the first guide portion. And a third guide part that is located on the upper side of the second guide part, contacts the sheet guided by the first guide part and the second guide part from the upper side, and curves the sheet downward. desirable.

  In this case, the first guide portion and the second guide portion are bent in a mountain shape. Here, if there is no third guide part, the sheet guided by the first guide part and the second guide part curves upward, and the inclination angle of the leading edge of the sheet with respect to the pressure plate tends to increase. Then, when a plurality of sheets are placed on the second placement section in a state where a large number of sheets are placed on the first placement section, a large number of sheets on the pressure plate at the separated position and upstream of the conveyance chute There is a possibility that the leading edge of the sheet may enter the gap with the side edge. Then, the pressure plate is displaced to the approach position, and when the feeding roller feeds the sheet placed on the second placing portion, the leading end of the sheet is clogged while entering the gap, and it is difficult to feed the sheet satisfactorily. .

  On the other hand, according to the above configuration, the sheet guided by the first guide part and the second guide part is curved downward by the third guide part, and the inclination angle of the leading edge of the sheet with respect to the pressure plate becomes small. For this reason, even when a large number of sheets are placed on the first placement portion and a sheet is placed on the second placement portion, the large number of sheets and the conveying chute on the pressure plate in the separated position It is difficult for the leading edge of the sheet to enter the gap with the upstream end of the sheet. For this reason, when the pressure plate is displaced to the approaching position and the feeding roller feeds the sheet placed on the second placement portion, it is difficult to cause a problem that the leading end of the sheet enters the gap and becomes clogged. As a result, in this sheet supply apparatus, even when a large number of sheets are placed on the first placement unit, the sheets placed on the second placement unit can be sent out satisfactorily.

  It is desirable that the first guide portion extends substantially horizontally. Moreover, it is desirable that the third guide portion is located below the upper surface of the first guide portion. In this case, since the first guide portion extends substantially horizontally, the apparatus can be thinned in the vertical direction. Further, the third guide portion positioned below the upper surface of the first guide portion reliably curves the sheet downward, and the inclination angle of the leading end of the sheet with respect to the pressure plate is reliably reduced.

  As for the lower end of the 3rd guide part, it is desirable that it is lower than the downstream end part of the sending direction in the 2nd guide part. In this case, the third guide portion whose lower end is lower than the downstream end portion of the second guide portion causes the sheet to be more reliably curved downward, and the inclination angle of the front end of the sheet with respect to the pressure plate is further reliably reduced.

  The third guide portion is preferably a single rib that protrudes downward so as to be able to come into contact with the center in the width direction of the sheet from above. In this case, since the frictional force between the third guide portion and the sheet is reduced, the sheet conveyance resistance can be reduced.

  An image forming apparatus according to the present invention includes the above-described sheet supply device and an image forming unit that is provided in the middle of the conveyance path and forms an image on the conveyed sheet.

  In the image forming apparatus of the present invention, the sheet placed on the second placement unit can be sent out satisfactorily by the operational effects exhibited by the sheet feeding apparatus of the present invention.

1 is a perspective view of an image forming apparatus in which a sheet supply apparatus according to an embodiment is used. FIG. 2 is a schematic cross-sectional view of the image forming apparatus showing a pressure plate and the like in a separated position. 2 is a schematic cross-sectional view of the image forming apparatus showing a pressure plate and the like in an approach position. FIG. FIG. 4 is a partial perspective view showing a pressure plate, a conveyance chute, a comb tooth portion, a third guide portion, and the like in a separated position in the image forming apparatus. FIG. 4 is a partial top view showing a pressure plate, a conveyance chute, a comb tooth portion, a separation pad, and the like according to the image forming apparatus. FIG. 4 is a partial perspective view showing a pressure plate, a second placement unit, a third guide unit, and the like, related to the image forming apparatus. FIG. 6 is a partial schematic cross-sectional view for explaining the behavior of the sheet placed on the second placement unit in a state where the sheet is not placed on the first placement unit in the image forming apparatus. FIG. 6 is a partial schematic cross-sectional view for explaining the behavior of the sheet placed on the second placement unit in a state where the sheet is not placed on the first placement unit in the image forming apparatus. FIG. 6 is a partial schematic cross-sectional view for explaining the behavior of a sheet placed on a second placement unit in a state where a large number of sheets are placed on a first placement unit in the image forming apparatus. FIG. 10 is a partial schematic cross-sectional view illustrating the behavior of a sheet placed on a second placement unit in a state where no sheet is placed on the first placement unit, according to an image forming apparatus of a comparative example. FIG. 10 is a partial schematic cross-sectional view illustrating the behavior of a sheet placed on a second placement unit in a state where no sheet is placed on the first placement unit, according to an image forming apparatus of a comparative example. FIG. 10 is a partial schematic cross-sectional view illustrating the behavior of a sheet placed on a second placement unit in a state where a large number of sheets are placed on a first placement unit, according to an image forming apparatus of a comparative example.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

(Example)
As shown in FIG. 1, the sheet supply apparatus 1 of the embodiment is used in an image forming apparatus 3. The sheet supply apparatus 1 is an example of a specific aspect of the sheet supply apparatus of the present invention. The image forming apparatus 3 is an example of a specific aspect of the image forming apparatus of the present invention. In FIG. 1, the side on which the opening 89 of the image forming apparatus 3 is provided is defined as the front side of the image forming apparatus 3, and the side that comes to the left hand when facing the opening 89 is defined as the left side of the image forming apparatus 3. Displays the front, back, left, and right directions. 2 are displayed in correspondence with the directions shown in FIG. 1. Hereinafter, each component provided in the image forming apparatus 3 will be described with reference to FIG.

<Schematic configuration of image forming apparatus>
As shown in FIGS. 1 and 2, the image forming apparatus 3 is a monochrome laser printer, and includes an apparatus main body 8, a transport unit 10, a first mounting unit 100, a second mounting unit 200, an image forming unit 20, and a discharge. A roller pair 19A, 19B is provided. The apparatus main body 8, the transport unit 10, the first placement unit 100, and the second placement unit 200 constitute the sheet supply device 1.

  The apparatus main body 8 is a substantially box-shaped body in which the rear surface 8R side is raised stepwise with respect to the front surface 8F side. As shown in FIG. 2, a conveyance chute 50, a conveyance unit holding frame 59, a frame member (not shown), and the like are provided inside the apparatus main body 8. An opening 89 that allows communication between the inside and the outside of the apparatus main body 8 is formed on the lower side of the front surface 8 </ b> F of the apparatus main body 8.

  As shown in FIGS. 1 and 2, a main body cover 7 that constitutes an upper outer surface of the apparatus main body 8 is provided on the upper side of the apparatus main body 8. The body cover 7 is bent in a crank shape along the stepped shape of the apparatus body 8 when viewed from the side.

  In the main body cover 7, a discharge tray 72 is formed on an upper surface extending on the front surface 8 </ b> F side of the apparatus main body 8. The main body cover 7 is provided with an auxiliary tray 72A. The auxiliary tray 72A extends forward with respect to the discharge tray 72 as shown by a two-dot chain line in FIG. 2, and covers the discharge tray 72 from above as shown by a solid line in FIG. Is supported by the body cover 7 so as to be displaceable between the two.

  As shown in FIGS. 1 and 2, a standing wall surface 7 </ b> W that is bent upward is formed on the rear end edge side of the discharge tray 72 in the main body cover 7. A discharge port 71 is formed in the standing wall surface 7W so as to communicate with the inside and outside of the apparatus main body 8.

  As shown in FIGS. 2 to 5, the conveyance chute 50 extends in the front-rear direction and the left-right direction along the rear surface 8 </ b> R in the apparatus main body 8. The conveyance chute 50 has an upstream end 50U and a guide 50D. The upstream end 50U is a plane that rises vertically from the bottom of the apparatus main body 8 while being spaced forward from the rear surface 8R. The guide portion 50D is an inclined surface that is inclined upward from the upper end edge side of the upstream end portion 50U toward the rear surface 8R.

  As shown in FIGS. 2 to 4 and 6, the conveyance unit holding frame 59 is located in the apparatus main body 8 above and in front of the guide unit 50 </ b> D of the conveyance chute 50 and extends in the left-right direction. doing.

  As shown in FIGS. 2 and 3, the apparatus main body 8 has a conveyance path P <b> 1 through which the sheet 99 is conveyed. The conveyance path P1 extends from the upper end edge of the upstream end portion 50U of the conveyance chute 50 toward the rear surface 8R of the apparatus body 8 along the guide portion 50D, and then changes its direction upward and extends substantially vertically. . Then, the transport path P <b> 1 turns forward at the lower side of the main body cover 7, extends toward the discharge port 71, and reaches the discharge tray 72.

  The conveyance unit 10 includes a delivery roller 11, a separation roller 12, a separation pad 13, and conveyance roller pairs 14A and 14B.

  The delivery roller 11 and the separation roller 12 are held by a conveyance unit holding frame 59. The separation roller 12 is positioned in front of the conveyance chute 50 and faces the guide portion 50D. The delivery roller 11 is positioned in front of the conveyance chute 50 and the separation roller 12. Further, the delivery roller 11 is located above a downstream end 110D of the pressure plate 110 described later.

  In the guide portion 50D, a separation pad 13 is provided at a position facing the separation roller 12 across the conveyance path P1. The separation pad 13 is pressed against the separation roller 12. As shown in FIG. 5, the delivery roller 11, the separation roller 12, and the separation pad 13 are located at the center in the left-right direction of the apparatus main body 8.

  The conveyance roller pairs 14A and 14B are positioned above the separation roller 12 and the separation pad 13 and face each other across the conveyance path P1.

  The first placement unit 100 is provided at the bottom of the apparatus main body 8. The first placement unit 100 includes an open / close tray 120, a pressure plate 110, and first side guides 130L and 130R.

  As shown in FIGS. 1 and 2, the openable tray 120 is a substantially flat plate member that is swingably supported on the lower edge side of the front surface 8 </ b> F of the apparatus body 8. The openable tray 120 opens the opening 89 in a state of extending substantially horizontally toward the front. Although not shown in the drawings, the openable tray 120 closes the opening 89 by swinging in an upright direction.

  The pressure plate 110 is a substantially flat plate member provided at the bottom of the apparatus main body 8 so as to extend in the front-rear direction. A plurality of sheets 99 are placed in a stacked state on the upper surface of the pressure plate 110 and the surface facing the upper side of the openable tray 120 in the opened state.

  The front end edge side of the pressure plate 110 is supported so as to be swingable around a swing axis X <b> 1 extending in the left-right direction on the lower end edge side of the front surface 8 </ b> F of the apparatus main body 8. As shown in FIG. 2, a displacement mechanism 119 is provided below the pressure plate 110 so as to extend substantially horizontally toward the rear. When the image forming apparatus 3 performs an image forming operation, the displacement mechanism 119 is rotated by being controlled by a control unit (not shown), and is displaced in a state of being inclined upward as shown in FIG. When the image forming operation is finished, the displacement mechanism 119 returns to the state shown in FIG.

  As shown in FIG. 4, the first side guides 130L and 130R are provided on the pressure plate 110 so as to be slidable in the left-right direction. The first side guides 130L and 130R extend in the front-rear direction while facing each other in the left-right direction.

  As shown in FIG. 2, a rack and pinion mechanism 139 is provided on the back surface of the pressure plate 110. The rack and pinion mechanism 139 is connected to the first side guides 130L and 130R. Accordingly, the first side guides 130L and 130R can be interlocked so as to approach or separate from each other in the left-right direction on the pressure plate 110, and the sheet 99 placed on the pressure plate 110 can be positioned in the width direction. . In the present embodiment, the width direction of the sheet 99 placed on the pressure plate 110 is the “left-right direction”.

  As shown in FIGS. 2 and 3 (not shown in FIG. 1), an end guide 121 is slidable in the front-rear direction on the surface of the openable open / close tray 120 facing upward. The rear end of the seat 99 can be regulated by moving the end guide 121 in the front-rear direction.

  As shown in FIG. 2, when the displacement mechanism 119 is not operating, the pressure plate 110 extends substantially horizontally and is spaced downward with respect to the delivery roller 11. The position of the pressure plate 110 shown in FIG. 2 is an example of the “separation position” in the present invention. Then, as shown in FIG. 3, when the displacement mechanism 119 rotates and displaces in a state where the displacement mechanism 119 rises and tilts rearward, the pressure plate 110 is pushed up by the displacement mechanism 119 and rises from the separated position, and is sent to the delivery roller 11. approach. The position of the pressure plate 110 shown in FIG. 3 is an example of the “approach position” in the present invention. The approach position varies depending on the number of stacked sheets on the pressure plate 110.

  When image formation is performed on the sheet 99 placed on the first placement unit 100, when the displacement mechanism 119 rotates and the pressure plate 110 is displaced to the approach position, the uppermost sheet placed on the pressure plate 110. 99 abuts on the delivery roller 11. The delivery roller 11 is controlled by a control unit (not shown) and rotates while being in contact with the delivery roller 11, thereby delivering the sheet 99 on the pressure plate 110 from the front to the rear. Thereby, the delivery roller 11 sends out the sheet 99 on the pressure plate 110 to the conveyance path P1. A direction from the front to the rear, which is the direction in which the sheet 99 is sent out to the conveyance path P1, is defined as a sending direction D1.

  As shown in FIGS. 4 and 5, the downstream end 110 </ b> D that is the downstream end of the pressure plate 110 in the delivery direction D <b> 1 is the upstream end that is the upstream end of the delivery chute 50 in the delivery direction D <b> 1. It faces 50U in the front-rear direction.

  The downstream end 110D of the pressure plate 110 and the upstream end 50U of the transport chute 50 have two comb teeth 300L and 300R. As shown in FIG. 5, the left comb-tooth portion 300 </ b> L and the right comb-tooth portion 300 </ b> R are located near the separation pad 13 at two positions sandwiching the separation pad 13 from the left-right direction.

  More specifically, as shown in FIGS. 4 and 5, the comb tooth portion 300 </ b> L includes a convex portion 111 </ b> L protruding in a rectangular shape from the downstream end portion 110 </ b> D toward the rear and a rearward direction from the upstream end portion 50 </ b> U. It consists of two corners 51L and 52L, which are concave corners recessed in a rectangular shape. The corner portions 51L and 52L are positioned so as to sandwich the convex portion 111L from the left-right direction. Further, the corner portions 51L and 52L extend from the lower end edge to the upper end edge of the upstream end portion 50U in the vertical direction. Thereby, a space is formed between the corner portions 51L and 52L to allow the vertical displacement of the convex portion 111L.

  Similarly to the comb-tooth portion 300L, the comb-tooth portion 300R also includes a convex portion 111R that protrudes in a rectangular shape from the downstream end portion 110D and a concave portion that is recessed in a rectangular shape from the upstream-side end portion 50U to the rear. It consists of corner portions 51R and 52R which are two corners. The corner portions 51R and 52R are located so as to sandwich the convex portion 111R from the left-right direction. The corner portions 51R and 52R also extend from the lower end edge to the upper end edge of the upstream end portion 50U in the vertical direction. As a result, a space is also formed between the corners 51R and 52R that allows the vertical displacement of the convex portion 111R.

  In such comb-tooth portions 300L and 300R, the convex portions 111L and 111R and the corner portions 51L, 52L, 51R and 52R mesh with each other in a comb-tooth shape in a state where the pressure plate 110 is in the separated position. In addition, in the entire range in which the pressure plate 110 is displaced from the separated position to the approaching position, the state where the convex portions 111L and 111R and the corner portions 51L, 52L, 51R, and 52R mesh with each other in a comb shape may be maintained. Further, even when the pressure plate 110 is slightly raised from the separation position and displaced to the approach position, the state where the convex portions 111L and 111R and the corner portions 51L, 52L, 51R, and 52R mesh with each other in a comb-tooth shape is eliminated. Good. In short, it is only necessary that the convex portions 111L, 111R and the corner portions 51L, 52L, 51R, 52R mesh with each other in a comb-tooth shape with at least the pressure plate 110 in the separated position.

  As shown in FIG. 1 to FIG. 3 and FIG. 6, the second placement unit 200 is located in the apparatus main body 8 above the first placement unit 100 and below the upper edge of the opening 89. Yes. The second placement unit 200 is for manually feeding a sheet 99 having a narrower width than the sheet 99 placed on the pressure plate 110 of the first placement unit 100.

  The second placement unit 200 includes a first guide unit 201, second side guides 230L and 230R, a second guide unit 202, and a third guide unit 203.

  The first guide portion 201 extends substantially horizontally from the front surface 8F side to the rear surface 8R side of the apparatus body 8, that is, from the upstream side to the downstream side in the delivery direction D1. The front end edge of the first guide portion 201 is located in the vicinity of the opening 89, and the rear end edge of the first guide portion 201 is located at the approximate center of the apparatus main body 8 in the front-rear direction.

  As shown in FIG. 6, the second side guides 230L and 230R are provided in the first guide part 201 so as to be slidable in the left-right direction. The second side guides 230L and 230R extend in the front-rear direction while facing each other in the left-right direction.

  As shown in FIG. 2, a rack and pinion mechanism 239 is provided on the back surface of the first guide portion 201. The rack and pinion mechanism 239 is connected to the second side guides 230L and 230R. Accordingly, the second side guides 230L and 230R are interlocked so as to approach or separate from each other in the left-right direction on the first guide unit 201, and in the width direction of the sheet 99 placed on the second placement unit 200. Positioning can be performed. The width of the sheet 99 on which the second side guides 230L and 230R can be positioned in the width direction is narrower than that of the first side guides 130L and 130R.

  5, the second side guides 230L and 230R position the sheet 99 having the minimum width Wn in the width direction on the second placement unit 200, as indicated by phantom lines. Can do. The comb tooth portions 300L and 300R are provided at positions where they can come into contact with the leading end 99A of the sheet 99 having the minimum width Wn placed on the second placement portion 200. That is, when the sheet 99 having the minimum width Wn is manually fed to the second placement unit 200 and the leading end 99A of the sheet 99 is inserted to the back of the apparatus main body 8 (to the rear surface 8R side), the leading end of the sheet 99 is inserted. 99A hangs over the end on the rear surface 8R side of the second stacking unit 200. At this time, the comb tooth portions 300L and 300R are in contact with the leading end 99A of the sheet 99. That is, the distance between the comb tooth portions 300L and 300R in the left-right direction is smaller than the minimum width Wn.

  As shown in FIG.6 and FIG.7, the 2nd guide part 202 is located downstream from the 1st guide part 201 in the sending direction D1. The second guide portion 202 is bent downward from the rear end edge of the first guide portion 201 and is inclined downward toward the rear surface 8R side. Thereby, the 1st guide part 201 and the 2nd guide part 202 are bent in mountain shape.

  The front surface 59F of the transport unit holding frame 59 faces the downstream end 202D of the second guide unit 202 in the sending direction D1 from the rear. The front surface 59F is inclined downward toward the rear surface 8R so as to follow the downward inclination of the second guide portion 202.

  The 3rd guide part 203 is one rib which protrudes below from the center of the left-right direction in the front surface 59F. As shown in FIG. 7, the third guide portion 203 is located below the upper surface of the first guide portion 201 and slightly above the second guide portion 202. The lower end 203A of the third guide portion 203 is lower than the downstream end portion 202D of the second guide portion 202 in the sending direction D1.

  In the second placement unit 200, the sheet 99 is manually fed in a state where the displacement mechanism 119 is not operating and the pressure plate 110 is in the separated position. Here, as shown in FIG. 7, when the sheet 99 is manually fed to the second placement unit 200 in a state where the sheet 99 is not placed on the pressure plate 110 of the first placement unit 100, the sheet 99. The front end 99A of the first guide part 201 is guided by the first guide part 201 and advances rearward substantially horizontally. Next, the leading end 99 </ b> A of the sheet 99 is guided by the second guide portion 202, proceeds while descending downward, and contacts the pressure plate 110. The leading end 99A of the manually fed sheet 99 advances backward while sliding on the pressure plate 110 and stops against the upstream end 50U of the conveyance chute 50.

  Then, as shown in FIG. 8, when the displacement mechanism 119 operates to form an image on the sheet 99 placed on the second placement unit 200 and the pressure plate 110 is displaced to the approach position, the second placement is performed. The front end 90 </ b> A side of the sheet 99 manually fed to the section 200 is pushed up by the pressure plate 110, and the front end 90 </ b> A side of the sheet 99 comes into contact with the feeding roller 11. The delivery roller 11 is controlled by a control unit (not shown) and rotates while being in contact with the sheet 99, so that the sheet 99 placed on the second placement unit 200 is directed from the front to the rear, that is, , Sent in the sending direction D1. Thereby, the sending roller 11 sends out the sheet 99 placed on the second placement unit 200 to the transport path P1.

  As shown in FIG. 9, when the sheet 99 is manually fed to the second placement unit 200 in a state where a large number of sheets 99 are placed on the pressure plate 110 at the separated position, The tip 99A is guided by the first guide part 201 and advances backward substantially horizontally. Next, the leading end 99 </ b> A of the sheet 99 is guided by the second guide portion 202 and proceeds while being inclined downward and comes into contact with the uppermost sheet 99 placed on the pressure plate 110. The leading end 99A of the manually fed sheet 99 advances backward while sliding on the uppermost sheet 99 on the pressure plate 110 and stops against the upstream end 50U of the conveyance chute 50.

  Although illustration is omitted, in this case as well, when the pressure plate 110 is displaced to the approach position, the leading end 90A side of the sheet 99 manually fed to the second placement unit 200 is pushed up by the pressure plate 110 and manually fed. Since the leading end 90A side of 99 abuts on the delivery roller 11, as described above, the manually fed sheet 99 is sent out to the transport path P1.

  As shown in FIGS. 2 and 3, the image forming unit 20 includes a process cartridge 21, a scanner unit 29, and a fixing device 30.

  The process cartridge 21 is located above the transport unit holding frame 59. The process cartridge 21 is a substantially box-like body extending in the left-right direction while inserting a substantially vertical portion of the transport path P1 into the inside. Inside the process cartridge 21, a photosensitive drum 22, a transfer roller 27, a toner container 24 that supplies toner to the photosensitive drum 22, a charger 25, and the like are provided.

  The photosensitive drum 22 is a cylindrical body extending in the left-right direction and faces the substantially vertical portion of the transport path P1 from the front. The transfer roller 27 faces the photosensitive drum 22 with the conveyance path P1 interposed therebetween. The photosensitive drum 22 and the transfer roller 27 are synchronously rotated while nipping the sheet 99 conveyed on a substantially vertical portion of the conveyance path P1. The charger 25 extends in the left-right direction in parallel with the photosensitive drum 22 while being spaced apart upward from the photosensitive drum 22. The charger 25 positively charges the photosensitive drum 22 by corona discharge.

  The scanner unit 29 is located in front of the process cartridge 21. The scanner unit 29 includes a laser light source, a polygon mirror, an fθ lens, a reflecting mirror, and the like, and irradiates a laser beam toward the photosensitive drum 22 located behind.

  The fixing unit 30 is located above the photosensitive drum 22 and the transfer roller 27 in a substantially vertical portion of the transport path P1. The fixing unit 30 includes a heating roller 31 that faces the conveyance path P1 from the front, and a pressure roller 32 that faces the heating roller 31 with the conveyance path P1 interposed therebetween.

  The discharge roller pair 19A, 19B is located at the most downstream side of the transport path P1, that is, at the portion whose direction changes to the front in the transport path P1, and faces the discharge port 71. The pair of discharge rollers 19A and 19B face each other so as to sandwich the transport path P1.

<Operation of image forming process>
The image forming apparatus 3 forms an image on the sheet 99 placed on the first placement unit 100 or the second placement unit 200 as follows. That is, when a control unit (not shown) starts control, the displacement mechanism 119 displaces the pressure plate 110 from the separated position to the approach position. As shown in FIG. 3, when the sheet 99 is not manually fed to the second placement unit 200, the delivery roller 11 contacts the sheet 99 placed on the pressure plate of the first placement unit 100. As shown in FIG. 8, when the sheet 99 is manually fed to the second placement unit 200, the delivery roller 11 contacts the manually fed sheet 99.

  Next, the conveyance unit 10, the image forming unit 20, and the discharge roller pair 19A and 19B operate in conjunction with each other. Then, the delivery roller 11 sends out the sheet 99 in contact with the conveyance path P1. The guide portion 50D of the conveyance chute 50 abuts on the sheet 99 to be delivered from below, and guides the sheet 99 to be conveyed along the conveyance path P1. The separation roller 12 and the separation pad 13 separate the fed sheets 99 one by one. The pair of conveyance rollers 14 </ b> A and 14 </ b> B conveys the separated sheet 99 toward the process cartridge 21.

  Next, in the process cartridge 21, the surface of the photosensitive drum 22 is uniformly positively charged by the charger 25 as it rotates, and then exposed to the laser beam emitted by the scanner unit 29. Thus, the scanner unit 29 forms an electrostatic latent image corresponding to the image to be formed on the surface of the photosensitive drum 22. Next, toner is supplied from the toner storage unit 24 to the electrostatic latent image on the surface of the photosensitive drum 22. As a result, a toner image corresponding to the electrostatic latent image is carried on the surface of the photosensitive drum 22. The toner image rotates while the photosensitive drum 22 is in contact with the conveyed sheet 99, and is transferred to the sheet 99 by the negative voltage applied to the transfer roller 27.

  The sheet 99 to which the toner image has been transferred is further conveyed substantially vertically along the conveyance path P <b> 1 and reaches the fixing unit 30. Then, the heating roller 31 heats the sheet 99 in the fixing unit 30. Further, the pressure roller 32 presses the sheet 99 toward the heating roller 31 to press the sheet 99. As a result, the fixing unit 30 fixes the toner image on the sheet 99. Thereafter, the sheet 99 is conveyed to the discharge roller pair 19 </ b> A and 19 </ b> B and discharged from the discharge port 71 toward the discharge tray 72. Thus, the image forming apparatus 3 ends the image forming process for the sheet 99.

<Effect>
In the sheet feeding apparatus 1 according to the embodiment, as illustrated in FIGS. 4, 5, and 7, the downstream end 110 </ b> D in the feeding direction D <b> 1 in the pressure plate 110 and the upstream end 50 </ b> U in the feeding direction D <b> 1 in the conveyance chute 50. The gap S <b> 1 is divided by comb teeth 300 </ b> L and 300 </ b> R that mesh with each other in a state where at least the pressure plate 110 is in the separated position, and does not extend linearly in the width direction of the sheet 99. For this reason, as shown in FIG. 7, even when the sheet 99 is placed on the second placement unit 200 in a state where the sheet 99 is not placed on the first placement unit 100, the comb tooth portions 300 </ b> L and 300 </ b> R. The leading end 99A of the sheet 99 manually fed to the second placement unit 200 does not enter the gap S1 divided by the above. For this reason, as shown in FIG. 8, when the pressure plate 110 is displaced to the approach position and the feeding roller 11 feeds the sheet 99 manually fed to the second placement unit 200, the leading end 99A of the sheet 99 has a gap S1. It is difficult for trouble to get stuck and get stuck.

  Further, as shown in FIG. 9, the third guide unit 203 is viewed from above at the center in the left-right direction on the upper surface of the sheet 99 that is manually fed and guided by the first guide unit 201 and the second guide unit 202. Abut. Therefore, since the manually fed sheet 99 is curved downward, the inclination angle α1 of the leading end 99A of the sheet 99 with respect to the pressure plate 110 becomes small. For this reason, even when the sheet 99 is placed on the second placement unit 200 in a state where a large number of sheets 99 are placed on the first placement unit 100, a large number of sheets on the pressure plate 110 in the separated position 99A is unlikely to enter the gap S2 between the sheet 99 and the upstream end 50U of the conveyance chute 50. For this reason, although illustration is omitted, when the pressure plate 110 is displaced to the approach position and the feeding roller 11 feeds the sheet 99 manually fed to the second placement unit 200, the leading end 99A of the sheet 99 is in the gap S2. It is difficult for troubles to get stuck.

  FIG. 10 shows an image forming apparatus of a comparative example. In the image forming apparatus of the comparative example, the comb tooth portions 300L and 300R and the third guide portion 203 are merely removed from the image forming apparatus of the embodiment. For this reason, the same code | symbol is attached | subjected about the structure same as an Example.

  In the image forming apparatus of the comparative example, a gap S3 between the downstream end portion 110D of the pressure plate 110 and the upstream end portion 50U of the conveyance chute 50 extends linearly in the left-right direction. Therefore, when the sheet 99 is manually fed to the second placement unit 200 in a state where no sheet is placed on the pressure plate 110, the downstream end 110D of the pressure plate 110 and the conveyance chute 50 at the separated positions are separated. There is a tendency that the leading end 99A of the manually fed sheet 99 enters the clearance S3 with the upstream end 50U. When such a problem occurs, as shown in FIG. 11, when the pressure plate 110 is displaced to the approach position, the manually fed sheet 99 is jammed with its leading end 99A entering the gap S3.

  Further, since the sheet feeding device of the comparative example does not have the third guide unit 203, as shown in FIG. 12, the sheet 99 guided by the first guide unit 201 and the second guide unit 202 bent in a mountain shape. Is curved upward, and the inclination angle α2 of the leading end 99A of the sheet 99 with respect to the pressure plate 110 tends to be large. Then, when the sheet 99 is manually fed to the second placement unit 200 in a state where a large number of sheets 99 are placed on the first placement unit 100, a large number of sheets on the pressure plate 110 in the separated position are placed. There is a tendency that the leading end 99A of the manually fed sheet 99 enters the gap S4 between the sheet 99 and the upstream end 50U of the conveyance chute 50. When such a problem occurs, illustration is omitted, but when the pressure plate 110 is displaced to the approaching position, the manually fed sheet 99 is jammed with its leading end 99A entering the gap S4. That is, the sheet 99 is lifted up by the pressure plate 100 while maintaining the upward curved shape, so that the leading end 99A remains facing downward.

  As a result, in the image forming apparatus of the comparative example, even if the sending roller 11 tries to send the sheet 99 manually fed to the second placement unit 200, it is difficult to send the sheet 99 well.

  Therefore, in the sheet supply apparatus 1 of the embodiment, from the state where the sheet 99 is not placed on the pressure plate 110 of the first placement unit 100 to the state where a large number of sheets 99 are placed on the pressure plate 110. The sheet 99 placed on the second placement unit 200 can be sent out satisfactorily.

  Further, in the sheet supply apparatus 1, the comb tooth portions 300 </ b> L and 300 </ b> R are provided at positions that can come into contact with the leading end 99 </ b> A of the sheet 99 having the minimum width Wn placed on the second placement portion 200. Thereby, in this sheet supply apparatus 1, since the comb-tooth portions 300L and 300R act on all the sheets 99 placed on the second placement unit 200 as described above, the sheets 99 are good. Can be sent out.

  Further, in the sheet supply apparatus 1, the comb tooth portions 300 </ b> L and 300 </ b> R are located at two locations that sandwich the separation pad 13 from the width direction of the sheet 99. Thereby, in this sheet supply apparatus 1, the sheet | seat 99 mounted in the 2nd mounting part 200 can be sent out favorably, reducing the installation location of the comb-tooth parts 300L and 300R. Further, the protrusions 111L and 111R are unlikely to interfere with the separation pad 13.

  Moreover, in this sheet supply apparatus 1, since the first guide portion 201 extends substantially horizontally, the apparatus can be thinned in the vertical direction. Further, the third guide portion 203 positioned below the upper surface of the first guide portion 201 ensures that the sheet 99 is bent downward and the inclination angle α1 of the leading end 99A of the sheet 99 with respect to the pressure plate 110 is reliably reduced. .

  Furthermore, in this sheet supply apparatus 1, the sheet 99 is more reliably curved downward by the third guide portion 203 whose lower end is lower than the downstream end portion 202D of the second guide portion 202, so that the sheet 99 with respect to the pressure plate 110 is curved. The inclination angle α1 of the leading end 99A of the tip is further reliably reduced.

  In the sheet supply apparatus 1, the third guide unit 203 is a single rib that protrudes downward so as to be able to come into contact with the center in the left-right direction of the sheet 99 from above. For this reason, in this sheet supply apparatus 1, since the frictional force between the 3rd guide part 203 and the sheet | seat 99 becomes small, the conveyance resistance of the sheet | seat 99 can be made small.

  Further, in the image forming apparatus 3 of the embodiment, the sheet 99 placed on the second placement unit 200 can be sent out satisfactorily due to the operational effects exhibited by the sheet supply apparatus 1 of the embodiment.

  In the sheet supply apparatus 1 according to the embodiment, the leading end 99A of the sheet 99 that extends from the downstream end 202D of the second guide unit 202 toward the feeding roller 11 and is manually fed to the second placement unit 200 is provided. By omitting the film guide that guides the pressure plate 110 so that it does not hang down, the manufacturing cost is reduced.

  While the present invention has been described with reference to the embodiments, it is needless to say that the present invention is not limited to the above-described embodiments and can be appropriately modified and applied without departing from the spirit thereof.

  For example, the pressure plate may be displaced from the separated position to the approach position by, for example, parallel movement.

  In the embodiment, the two comb tooth portions 300L and 300R are provided. However, the present invention is not limited to this configuration. For example, only one comb tooth portion may be provided, or three or more comb tooth portions may be arranged. .

  The present invention can be used for an image forming apparatus, an image reading apparatus, a multifunction peripheral, or the like.

DESCRIPTION OF SYMBOLS 1 ... Sheet supply apparatus, 3 ... Image forming apparatus, 20 ... Image forming part 99 ... Sheet, P1 ... Conveyance path, 11 ... Sending roller, 110 ... Pressure plate 100 ... 1st mounting part, 200 ... 2nd mounting part D1 ... delivery direction, 50 ... transport chute, 13 ... separation pad 110D ... downstream end in feed direction in pressure plate 50U ... upstream end in feed direction in transport chute 300L, 300R ... comb teeth, Wn ... minimum width, 99A ... Sheet leading edge 201... First guiding portion 202. Second guiding portion 203. Third guiding portion 203 A. Lower end of third guiding portion 202 D.

Claims (8)

A conveyance path through which the sheet is conveyed;
A delivery roller for feeding the sheet to the transport path;
The sheet having a pressure plate that is displaceable between a separation position that is spaced downward with respect to the delivery roller and an approach position that is raised from the separation position and approaches the delivery roller, and is sent to the conveyance path A first placement portion placed on the pressure plate;
A second placement unit that is located on the upper side of the first placement unit and on which the other sheet sent to the transport path is placed;
A transport chute that is positioned downstream of the transport roller in the transport direction in which the sheet is transported, contacts the transported sheet from below, and guides the sheet to be transported along the transport path. ,
The feeding roller abuts on the sheet placed on the first placement portion or the second placement portion when the pressure plate is displaced from the separation position to the approach position, and conveys the sheet. To the route,
The downstream end of the pressure plate in the delivery direction and the upstream end of the transport chute in the delivery direction are comb teeth that mesh with each other in a comb shape with at least the pressure plate in the spaced position. A sheet supply apparatus comprising:   The sheet feeding device according to claim 1, wherein the comb-tooth portion is provided at a position where the comb tooth portion can be brought into contact with a front end of the sheet having the minimum width placed on the second placement portion. A separation pad provided on the conveyance chute, for separating the sheets sent to the conveyance path one by one;
3. The sheet feeding device according to claim 1, wherein the comb-tooth portions are located at at least two positions sandwiching the separation pad from a width direction of the sheet.   The second mounting portion is located on the downstream side of the first guide portion in the delivery direction, and is bent downward from the first guide portion, extending from the upstream side to the downstream side in the delivery direction. A second guide portion that is positioned above the second guide portion, abuts against the sheet guided by the first guide portion and the second guide portion from above, and is configured to bend the sheet downward. The sheet supply apparatus according to any one of claims 1 to 3, further comprising a guide unit. The first guide portion extends substantially horizontally,
The sheet feeding apparatus according to claim 4, wherein the third guide unit is located below the upper surface of the first guide unit.   The sheet feeding apparatus according to claim 5, wherein a lower end of the third guide portion is lower than a downstream end portion of the second guide portion in the feeding direction.   7. The sheet feeding apparatus according to claim 5, wherein the third guide portion is a single rib that protrudes downward so as to come into contact with the center in the width direction of the sheet from above. The sheet feeding device according to any one of claims 1 to 7,
An image forming apparatus comprising: an image forming unit that is provided in the middle of the transport path and forms an image on the transported sheet.

Images