JP2018203479A - Sheet conveying apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet transfer device capable of miniaturization and an image forming device including the same. SOLUTION: A cassette 61 on which a sheet is loaded, a feeding unit 70 for feeding the sheet loaded on the cassette 61 to a cassette transport path R1, and a cassette transport path upstream of the feed unit 70 in the sheet transport direction. A transport roller pair 96 provided in the manual feed transport path R2 that joins R1 and transports the sheet, and a transport roller pair 96 provided along the manual feed transport path R2 and arranged between the transport roller pair 96 and the feeding unit 70 in the sheet transport direction. It is provided with a tip detection unit 97 that outputs a detection signal according to the position of the sheet conveyed by the transfer roller pair 96. The drive of the transport roller pair 96 is such that the tip of the sheet to be transported is located upstream of the feeding unit 70 and downstream of the tip detection unit 97 in the sheet transport direction based on the detection signal output by the tip detection unit 97. So that it will be stopped. [Selection diagram] FIG. 5

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet and an image forming apparatus including the sheet conveying apparatus.

  In general, an image forming apparatus such as a printer has a configuration including a manual feeding unit that manually feeds and feeds a sheet according to a use in addition to a cassette feeding unit that feeds sheets stacked in a cassette. ing. 2. Description of the Related Art Conventionally, there has been proposed a printer that pulls a sheet placed on a manual feed table into a device by a manual feed roller when a sheet placed on the manual feed table is detected by a first detector (Patent Document 1). reference). The sheet drawn into the apparatus is stopped after a predetermined time from being detected by the second detector.

JP-A-55-151653

  However, in the printer described in Patent Document 1, a manual conveyance path is provided immediately above a cassette and a feeding roller that feeds the sheets stacked on the cassette, and the manual conveyance path is more sheet-shaped than the feeding roller. It joins the cassette conveyance path downstream in the conveyance direction. For this reason, a space sufficient to provide a feeding roller is required between the cassette and the manual conveyance path, and the apparatus has been enlarged particularly in the vertical direction.

  Therefore, the present invention provides a sheet conveying apparatus and an image forming apparatus including the sheet conveying apparatus that are configured such that the second conveying path is joined upstream of the feeding unit in the sheet conveying direction. With the goal.

  The present invention provides a sheet conveying apparatus, a sheet stacking unit on which sheets are stacked, a feeding unit that feeds a sheet stacked on the sheet stacking unit to a first transport path, and a sheet transport than the feeding unit. Provided in a second conveyance path that joins the first conveyance path upstream in the direction, and is provided along the second conveyance path, and is provided along the second conveyance path. A sheet detecting unit disposed between the sheet feeding unit and the sheet detecting unit that outputs a detection signal according to a position of the sheet conveyed by the conveying unit, and the sheet conveyed to the first conveying path by the conveying unit. Is conveyed by the feeding unit, and the conveyance unit is driven based on a detection signal output by the sheet detection unit so that the leading edge of the sheet conveyed through the second conveyance path is In preparative conveying direction so as to be positioned downstream from the upstream and the sheet detecting means than the feeding means is stopped, characterized in that.

  According to the present invention, since the second conveyance path merges with the first conveyance path upstream of the feeding unit in the sheet conveyance direction, the distance between the first conveyance path and the second conveyance path can be narrowed and the size can be reduced. Can do. In addition, since the sheet detecting means is disposed between the conveying means and the feeding means, the leading edge of the sheet can be stopped with respect to the feeding means with high accuracy, and the sheet is drawn into the apparatus until just before the feeding means. be able to. Accordingly, it is possible to reduce an erroneous operation in which the sheet hangs out of the apparatus and the user pushes or pulls the sheet.

1 is an overall schematic diagram illustrating a printer according to a first embodiment. The schematic diagram which shows a sheet feeding apparatus. (A) is a schematic diagram which shows the state which the pickup roller is raising, (b) is a schematic diagram which shows the state in which the pickup roller is contacting the sheet | seat. The schematic diagram which shows a mode that a sheet | seat is returned to a cassette by a return nail | claw. (A) is a schematic diagram which shows the state which inserted the sheet | seat manually in the manual feed port, (b) is a schematic diagram which shows the state by which the sheet | seat was drawn in in the apparatus. FIG. 4A is a schematic diagram illustrating a state where sheets are joined from a manual conveyance path to a cassette conveyance path, and FIG. 4B is a schematic diagram illustrating a state in which the manually fed sheet is conveyed by a pickup roller. FIG. 9 is a schematic diagram illustrating a sheet feeding apparatus according to a second embodiment. (A) is a schematic diagram which shows the state which the intermediate plate is falling, (b) is a schematic diagram which shows the state which the intermediate plate raised. (A) is a schematic diagram which shows the state which inserted the sheet | seat manually in the manual feed port, (b) is a schematic diagram which shows the state by which the sheet | seat was drawn in in the apparatus. FIG. 4A is a schematic diagram illustrating a state where sheets are joined from a manual conveyance path to a cassette conveyance path, and FIG. 4B is a schematic diagram illustrating a state in which the manually fed sheet is conveyed by a pickup roller.

<First Embodiment>
〔overall structure〕
First, a first embodiment of the present invention will be described. A printer 100 as an image forming apparatus is an electrophotographic laser beam printer. As illustrated in FIG. 1, an image forming unit 20 that forms an image on a sheet S, a sheet feeding device 60, a fixing device 30, and the like. , And a discharge roller pair 40. The image forming unit 20 serving as an image forming unit includes four process cartridges PY, PM, PC, which form toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively. PK and scanner unit 19 are provided.

  The four process cartridges PY, PM, PC, and PK have the same configuration except that the colors of images to be formed are different. Therefore, only the configuration of the process cartridge PY and the image forming process will be described, and the description of the process cartridges PM, PC, and PK will be omitted.

  The process cartridge PY includes a photosensitive drum 11, a charging roller 12, and a developing roller 13. The photosensitive drum 11 is configured by applying an organic photoconductive layer to the outer periphery of an aluminum cylinder, and is rotated by a drive motor (not shown). The image forming unit 20 includes an intermediate transfer belt 21 that is stretched by a driving roller 22, a driven roller 24, and a tension roller 23. The intermediate transfer belt 21 is rotated by a driving roller 22, and the driving roller 22 faces the secondary transfer roller 26 with the intermediate transfer belt 21 interposed therebetween. Inside the intermediate transfer belt 21, primary transfer rollers 15a, 15b, 15c, and 15d are provided. The fixing device 30 includes a fixing film 31 that is heated by a heater, and a pressure roller 32 that is in pressure contact with the fixing film 31. The sheet feeding device 60 is provided below the printer 100 and accommodates the sheet S.

  Next, an image forming operation of the printer 100 configured as described above will be described. When an image signal is input to the scanner unit 19 from a personal computer (not shown), the laser light corresponding to the image signal is emitted from the scanner unit 19 onto the photosensitive drum 11 of the process cartridge PY.

  At this time, the surface of the photosensitive drum 11 is uniformly charged to a predetermined polarity and potential in advance by the charging roller 12, and an electrostatic latent image is formed on the surface by irradiating laser light from the scanner unit 19. . The electrostatic latent image formed on the photosensitive drum 11 is developed by the developing roller 13 to form a yellow (Y) toner image on the photosensitive drum 11.

  Similarly, the photosensitive drums of the process cartridges PM, MC, and PK are also irradiated with laser light from the scanner unit 19, and magenta (M), cyan (C), and black (K) toner images are formed on the photosensitive drums. Is done. The toner images of the respective colors formed on the respective photosensitive drums are transferred to the intermediate transfer belt 21 by the primary transfer rollers 15a, 15b, 15c, and 15d, and up to the secondary transfer roller 26 by the intermediate transfer belt 21 rotated by the driving roller 22. Be transported. The image forming process for each color is performed at the timing of superimposing on the upstream toner image primarily transferred onto the intermediate transfer belt 21.

  In parallel with this image forming process, the sheet S accommodated in the sheet feeding device 60 is fed out by a feeding unit 70 as a feeding unit and hits the nip of the registration roller pair 80 in a stopped state. The line is corrected. Then, the sheet S is conveyed toward the secondary transfer roller 26 by the registration roller pair 80 at a predetermined timing, and the full color on the intermediate transfer belt 21 is applied by the secondary transfer bias applied to the secondary transfer roller 26. The toner image is transferred. The sheet S to which the toner image has been transferred is given predetermined heat and pressure by the fixing film 31 and the pressure roller 32 of the fixing device 30, and the toner is melted and fixed (fixed). The sheet S that has passed through the fixing device 30 is discharged to the discharge tray 50 by the discharge roller pair 40.

[Sheet feeding device]
Next, the sheet feeding apparatus 60 as the sheet conveying apparatus will be described in detail with reference to FIG. The sheet feeding device 60 includes a cassette 61 as sheet stacking means that can be inserted into and removed from the apparatus main body 101 (see FIG. 1) of the printer 100, and a feeding unit 70 that feeds the sheets stored in the cassette 61. And a manual feed unit 90.

  The cassette 61 includes a cassette body 61a as a loading body, a middle plate 62 supported by the cassette body 61a so as to be movable up and down around a fulcrum 62a, and a cassette shaft 61a around a rotation shaft 63a. And a lift arm 63 that is rotatably supported. The lift arm 63 is driven by a drive source (not shown) so as to press the intermediate plate 62 upward. As a result, the intermediate plate 62 rises. A downstream side of the sheet S in the sheet conveyance direction is supported by the intermediate plate 62 as a stacking unit, and the downstream side of the sheet S rises when the intermediate plate 62 rises. The cassette 61 is provided with a pair of side regulating plates (not shown) that regulate the position of the sheets stacked on the intermediate plate 62 in the width direction orthogonal to the sheet feeding direction.

  The manual feed unit 90 is disposed above the cassette 61 and is provided as a guide member that is detachably supported with respect to the apparatus main body 101 (see FIG. 1), and the lower guide 91 is disposed above the lower guide 91. And an upper guide 92 facing each other. The lower guide 91 and the upper guide 92 constitute a manual conveyance path R2 as a second conveyance path for conveying a sheet inserted from the manual feeding port 93. The manual conveyance path R2 is located above the cassette 61. Is provided. In other words, the lower guide 91 constitutes a part of the manual feed path R2. When a sheet is jammed in the manual feed path R2, it is possible to access the manual feed path R2 from the cassette insertion space by removing the lower guide 91 and the cassette 61 from the apparatus main body 101, and easily perform the jam processing. Can do. The jammed sheet may be taken out by moving or swinging the lower guide 91 downward to open the manual feed path R2.

  The manual feed unit 90 includes a pull-in sensor unit 94, a transport unit 190, and a leading edge detection unit 97 in order from the upstream side to the downstream side in the sheet transport direction along the manual transport path R2. The conveyance unit 190 as a conveyance unit has a plurality (two in this embodiment) of conveyance roller pairs, and is arranged at the most downstream side with the pulling roller pair 95 arranged at the most upstream side in the sheet conveyance direction. A pair of transport rollers 96. The transport unit 190 may have three or more transport roller pairs. The pull-in sensor unit 94 includes a first flag member 94a that rotates when pressed against the leading edge of the sheet, and a first detection sensor 94b that is turned on from the OFF state when the optical path is blocked by the first flag member 94a. And have. The first flag member 94a as a moving unit is held by a spring and a stopper (not shown) at a protruding position protruding in the manual conveyance path R2, and retracts from the manual conveyance path R2 by pressing against the leading edge of the sheet S. The first detection sensor 94b as the detection unit outputs a detection signal that is different between the OFF state and the ON state to the control unit 45 (see FIG. 1), and the control unit 45 causes the first detection sensor 94b to be in the ON state. Then, it is detected that the sheet S is inserted into the manual feed port 93. That is, the pull-in sensor unit 94 serving as an insertion sheet detecting unit is disposed upstream of the pair of pull-in rollers 95 serving as a pulling unit in the sheet conveyance direction, and generates a detection signal according to the position of the sheet inserted into the manual conveyance path R2. Output.

  The leading edge detection unit 97 is disposed between the conveyance roller pair 96 and the feeding unit 70 in the sheet conveyance direction, and has the same configuration as the pull-in sensor unit 94. That is, the leading edge detection unit 97 is rotated by being pressed against the leading edge of the sheet, and the second detection is switched from the OFF state to the ON state when the optical path is blocked by the second flag member 97a. And a sensor 97b. The second flag member 97a is held by a spring and a stopper (not shown) at a protruding position protruding in the manual conveyance path R2, and retracts from the manual conveyance path R2 when pressed against the leading edge of the sheet S. The second detection sensor 97b outputs a detection signal that differs between the OFF state and the ON state to the control unit 45 (see FIG. 1). That is, the leading edge detection unit 97 as a sheet detection unit outputs a detection signal according to the position of the sheet conveyed by the conveyance roller pair 96.

  The feeding unit 70 includes a pickup roller 71 capable of feeding the sheets S stacked on the intermediate plate 62, a feed roller 72 and a separation roller 73 that separate the sheets S fed by the pickup roller 71 one by one. ,have. The pickup roller 71 as a feeding unit is supported so as to be movable up and down and rotatable by a pickup arm 74 that is rotatably supported on the rotation shaft of the feed roller 72. That is, the pickup roller 71 can be moved toward and away from the sheets S stacked on the cassette 61 and can move relative to the cassette body 61 a of the cassette 61.

  The separation roller 73 is supported so as to be able to contact and separate from the feed roller 72 and to be rotatable by a separation arm 75 that is rotatably supported by the feeding frame 102. Further, a return claw 76 is supported on the feeding frame 102 so as to be rotatable about a rotation center 76a, and the sheet S conveyed by the feeding unit 70 passes through the return claw 76 in FIG. It protrudes to the cassette conveyance path R1 as the first conveyance path. The manual conveyance path R2 through which the manually inserted sheet passes joins the cassette conveyance path R1 upstream of the feeding unit 70 in the sheet conveyance direction.

  The sheet feeding device 60 selects either a cassette feeding operation in which the sheet S is fed from the cassette 61 or a manual feeding operation in which the sheet S is fed from the manual feeding port 93. To feed.

[Cassette feeding operation]
Next, a cassette feeding operation in which the sheet S is fed from the cassette 61 will be described with reference to FIGS. As shown in FIG. 3A, when the sheet S is not fed, the pickup roller 71 is separated from the uppermost surface SS of the sheet S stacked on the intermediate plate 62, and the separation roller 73 is fed. It is separated from the roller 72. When a cassette feeding command is output from the control unit 45, the pickup arm 74 is lowered by a motor (not shown) and the pickup roller 71 and the feed roller 72 are driven as shown in FIG. Further, when the separation arm 75 is driven, the separation roller 73 comes into contact with the feed roller 72 to form a separation nip N as a separation portion, and the return claw 76 is separated from the cassette conveyance path R1.

  When the pickup roller 71 comes into contact with the uppermost surface SS of the sheet S, the uppermost sheet is sent out toward the separation nip N by the pickup arm 74. The pickup roller 71 rises when the uppermost sheet S is conveyed to the separation nip N, and waits while being separated from the uppermost surface SS of the sheet S.

  A torque limiter (not shown) is connected to the separation roller 73, and when only one sheet is sent out by the pickup roller 71, a load exceeding the limiter value acts on the torque limiter. As a result, the torque limiter idles, and the separation roller 73 rotates with the feed roller 72. When two or more sheets are sent out by the pickup roller 71, only a load less than the limit value acts on the torque limiter, and the separation roller 73 stops without being driven by the feed roller 72. As a result, the sheets S are separated one by one in the separation nip N.

  When the sheets separated one by one in the separation nip N reach the registration roller pair 80 (see FIG. 2), the separation roller 73 is separated from the feed roller 72 by driving the separation arm 75. At the same time, the return claw 76 rotates clockwise, so that the sheet staying at the separation nip N is pushed by the return claw 76 and returned to the cassette 61.

[Manual feeding operation]
Next, the manual feeding operation in which the sheet S is fed from the manual feeding port 93 will be described with reference to FIGS. 5A to 6B. First, the manual feeding operation will be described. When the sheet S is inserted into the manual feed port 93 by the user, as shown in FIG. 5A, the contact surface 94c of the first flag member 94a is pressed by the leading end of the sheet S, and the first flag member 94a. Rotates clockwise. Then, the first flag member 94a shields the optical path of the first detection sensor 94b, and outputs a detection signal indicating that the first detection sensor 94b has changed from the OFF state to the ON state.

  Based on the fact that the control unit 45 (see FIG. 1) has received the detection signal from the first detection sensor 94b, the control unit 45 drives the pull-in roller pair 95 and the transport roller pair 96. As a result, the manually fed sheet S is conveyed along the manual conveyance path R2, and the contact surface 97c of the second flag member 97a is pressed by the leading edge of the sheet S. Then, the second flag member 97a rotates clockwise, the optical path of the second detection sensor 97b is shielded by the second flag member 97a, and a detection signal indicating that the second detection sensor 97b has changed from the OFF state to the ON state. Is output.

  When the control unit 45 receives the detection signal from the second detection sensor 97b, the control unit 45 stops driving the pull-in roller pair 95 and the conveyance roller pair 96 after a predetermined time, as shown in FIG. 5B. In the present embodiment, the manually fed sheet S is pulled to a position where the leading end of the sheet coincides with the downstream end 91 a of the lower guide 91 and stops. That is, based on the detection signal output by the pull-in sensor unit 94, the sheet S is stopped in a state where the leading end is positioned upstream of the feeding unit 70 and downstream of the pull-in sensor unit 94 in the sheet conveyance direction.

  Here, in the present embodiment, the length L in the sheet conveyance direction of the manual conveyance path R2 is set to be equal to or longer than the length of the A4-sized sheet that is frequently used. Specifically, the length L of the manual feed path R2 is set to 297 mm or more, which is the length of the A4 size sheet. The length L of the manual feed path R2 is the sheet from the reference position of the downstream end 91a of the lower guide 91 in the sheet conveyance direction or the leading end of the stopped sheet to the manual feed port 93, that is, the front side surface 103 of the printer 100. It is the length in the transport direction. The reference position is a position where the leading edge of the sheet is stopped in the manual feed path R2 by design.

  As described above, in the present embodiment, based on the detection signal of the leading edge detection unit 97, the sheet S is manually conveyed to the position where the leading edge of the manually fed sheet S does not contact the pickup roller 71 of the feeding unit 70. Pull in. Since the leading edge detection unit 97 is arranged downstream of the conveyance roller pair 96 in the sheet conveyance direction, the stop position accuracy of the sheet S can be improved. Since the length L2 of the manual feed path R2 is set to be equal to or greater than the length of the frequently used A4 size sheet, the trailing edge of the sheet S can be positioned in the manual feed path R2. As a result, the rear end of the sheet S is accommodated in the manual conveyance path R2, and the sheet S does not protrude outwardly from the manual feed port 93 and hangs down. Therefore, the sheet S is pulled or pushed by the user. Erroneous operation can be reduced. In other words, the trailing edge of a sheet of A4 size or less that is a predetermined size or less is accommodated in the manual feed path R2. Even when the manual sheet S is pulled into the manual feed path R2 and set, or when the cassette feeding operation is selected, the manually fed sheet S does not interfere with the cassette feeding operation.

  When the manual feeding operation is selected in the state where the manually fed sheet S is set, the control unit 45 drives the drawing roller pair 95 and the conveyance roller pair 96 again, and as shown in FIG. The sheet S joins the cassette conveyance path R1. When the pickup roller 71 is lowered in this state, the manually fed sheet S is sandwiched between the pickup roller 71 and the uppermost surface SS of the sheets stacked on the cassette 61 as shown in FIG. And is conveyed by the pickup roller 71. Similarly to the cassette feeding operation described above, the sheets S are separated one by one by the separation nip N and conveyed to the registration roller pair 80. That is, the feeding unit 70 is configured to be able to feed the sheets stacked on the cassette 61 or to convey the sheets conveyed by the conveying roller pair 96.

  As described above, in the present embodiment, the feeding unit 70 that feeds the sheets stacked on the cassette 61 is configured to also transport the manually fed sheets. The manual conveyance path R2 joins the cassette conveyance path R1 upstream of the feeding unit 70 in the sheet conveyance direction. For this reason, the space for arranging the feeding unit 70 is not required between the cassette 61 and the manual feed path R2, and the printer 100 can be downsized in the vertical direction.

  Further, in the present embodiment, the length L of the manual feed path R2 is set to be equal to or longer than the length of the A4 size sheet, and the manually fed sheet S is pulled into the manual feed path R2. For this reason, the drawn sheet S does not protrude outwardly from the manual feed port 93 and hangs down, and an erroneous operation in which the user pulls or pushes in the sheet S can be reduced. Since the manually fed sheet S is stopped based on the detection signal of the leading edge detection unit 97 provided downstream in the sheet conveyance direction from the conveyance roller pair 96, the sheet S can be accurately stopped.

  In this embodiment, the length L of the manual feed path R2 is set to be equal to or longer than the length of the A4 size sheet (297 mm), but is not limited thereto. That is, when the manually fed sheet S is pulled into the manual conveyance path R <b> 2 and the user cannot grip the sheet S, the rear end of the sheet S protrudes outward from the manual feeding port 93 of the printer 100. It may be. In addition, when a sheet having a size longer than A4 size such as legal size (215.9 mm × 355.6 mm) is used, even if the sheet is set in the manual feed port 93, the sheet can be removed from the manual feed port 93. It protrudes about 50mm outside the device. Even in this case, since the amount of protrusion from the manual feed port 93 to the outside of the apparatus is small, even if the user touches the sheet, the amount of deviation of the sheet is small and erroneous operation can be reduced. Further, as long as the sheet can be used by the printer 100, the length L of the manual conveyance path R2 may be set so that the trailing edge of the sheet of any size can be drawn into the manual conveyance path R2. .

<Second Embodiment>
Next, a second embodiment of the present invention will be described. In the second embodiment, the pickup roller according to the first embodiment is configured so as not to be moved up and down. For this reason, about the structure similar to 1st Embodiment, illustration is abbreviate | omitted or attaches | subjects the same code | symbol to a figure and demonstrates.

  As shown in FIG. 7, the sheet feeding device 160 as the sheet conveying device according to the present embodiment feeds the sheets S stacked on the cassette 61 and conveys the sheets inserted from the manual feeding port 93. It has a feeding unit 170 as a feeding means. The feeding unit 170 has a conveyance guide 174 disposed above the cassette 61 and downstream of the manual conveyance path R2 in the sheet conveyance direction. The pickup roller 71 and the feed roller 72 are rotatable in the conveyance guide 174. It is supported by. That is, the pickup roller 71 cannot move with respect to the cassette body 61 a of the cassette 61.

[Cassette feeding operation]
As shown in FIGS. 7 and 8A and 8B, when the cassette feeding operation is performed, the middle plate 62 rises around the fulcrum 62a, and the uppermost sheet S stacked on the middle plate 62 is placed. The surface SS comes into contact with the pickup roller 71. When the sheet S is conveyed to the separation nip N by the pickup roller 71, the intermediate plate 62 is lowered to prepare for the next feeding operation. Since the subsequent steps are the same as those in the first embodiment, description thereof is omitted.

[Manual feeding operation]
When the sheet S is inserted into the manual feed port 93, as shown in FIGS. 9A and 9B, the sheet S is pulled by the pulling roller pair 95 and the conveying roller pair 96 as in the first embodiment. It is pulled in and stops at a position where the tip coincides with the downstream end 91 a of the lower guide 91. Also in this embodiment, the length L in the sheet conveyance direction of the manual conveyance path R2 is set to be equal to or longer than the length of the A4-sized sheet that is frequently used.

  When the manual feeding operation is selected with the manually fed sheet S set, the control unit 45 drives the drawing roller pair 95 and the conveyance roller pair 96 again, as shown in FIG. Then, the sheet S joins the cassette conveyance path R1. When the intermediate plate 62 rises in this state, the manually fed sheet S is sandwiched between the pickup roller 71 and the uppermost surface SS of the sheets stacked on the cassette 61 as shown in FIG. And is conveyed by the pickup roller 71. Similarly to the cassette feeding operation described above, the sheets S are separated one by one by the separation nip N and conveyed to the registration roller pair 80.

  As described above, even in the configuration in which the pickup roller 71 does not move up and down, the sheet S stacked on the cassette 61 and the manually fed sheet can be conveyed by the feeding unit 170. In addition, since the arm for raising and lowering the pickup roller 71 can be omitted, the number of parts can be reduced and the cost can be reduced.

  In any of the above-described forms, two roller pairs and two sensor units are provided along the manual feed path R2. However, the present invention is not limited to this, and one roller pair and one sensor unit may be provided. Good. That is, the roller pair is driven by detecting that the sheet has been inserted into the manual feed port 93, and the roller pair is stopped when the leading edge of the sheet reaches the front of the pickup roller 71. May be. Further, the sensor unit is not limited to the flag type, and other transport methods such as belt transport may be applied instead of the roller pair.

  In any of the above-described embodiments, the sheets are separated one by one by the feed roller 72 and the separation roller 73 using the separation roller method, but the present invention is not limited to this. That is, a retard roller method in which reverse driving is input to the separation roller 73 or a pad separation method using a separation pad may be applied.

  In any of the above-described embodiments, the electrophotographic printer 100 has been described, but the present invention is not limited to this. For example, the present invention can be applied to an inkjet image forming apparatus that forms an image on a sheet by ejecting ink liquid from a nozzle.

  20: Image forming unit (image forming unit) / 60, 160: Sheet conveying device (sheet feeding device) / 61: Sheet stacking unit (cassette) / 61a: Stacking main unit (cassette main unit) / 62: Stacking unit ( Middle plate) / 70, 170: feeding means (feeding unit) / 71: feeding section (pickup roller) / 91: guide member (lower guide) / 94: insertion sheet detecting means (pull-in sensor unit) / 94a: Moving part (first flag member) / 94b: detection part (first detection sensor) / 95: pulling means (pulling roller pair, transporting roller pair) / 96: transporting roller pair / 97: sheet detecting means (tip detection unit) / 190: Conveying means (conveying unit) / N: Separating part (separating nip) / R1: First conveying path (cassette conveying path) / R2: Second conveying path (manually conveying path)

Claims (16)

Sheet stacking means on which sheets are stacked;
A feeding means for feeding the sheets stacked on the sheet stacking means to the first transport path;
A conveying unit that conveys the sheet, provided in a second conveying path that joins the first conveying path upstream in the sheet conveying direction from the feeding unit;
It is provided along the second conveyance path, and is arranged between the conveyance unit and the feeding unit in the sheet conveyance direction, and outputs a detection signal according to the position of the sheet conveyed by the conveyance unit. Sheet detecting means,
The sheet conveyed to the first conveyance path by the conveyance unit is conveyed by the feeding unit,
Based on the detection signal output by the sheet detection means, the conveyance means is driven so that the leading edge of the sheet conveyed on the second conveyance path is upstream of the feeding means in the sheet conveyance direction and the sheet detection means. Is stopped so as to be located downstream,
A sheet conveying apparatus. The transport means includes a plurality of transport roller pairs arranged along the second transport path,
The sheet detection unit is disposed on the second conveyance path downstream of the conveyance roller pair disposed on the most downstream side in the sheet conveyance direction among the plurality of conveyance roller pairs.
The sheet conveying apparatus according to claim 1. On the second conveyance path, a detection signal is sent according to the position of the sheet that is arranged upstream of the conveyance roller pair that is arranged upstream of the plurality of conveyance roller pairs, and is inserted into the second conveyance path. An insertion sheet detection means for outputting,
The conveying means is driven based on a detection signal output from the insertion sheet detection means, and is stopped based on a detection signal output from the sheet detection means.
The sheet conveying apparatus according to claim 2. The trailing edge of the sheet that has been transported through the second transport path by the transport unit and stopped based on detection by the sheet detection unit is located in the second transport path.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. A trailing edge of a sheet of a predetermined size or less stopped by the conveying unit is located in the second conveying path;
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The sheet of the predetermined size is an A4 size sheet.
The sheet conveying apparatus according to claim 5. The conveyance unit includes a conveyance roller pair disposed on the second conveyance path, and a drawing unit that is disposed upstream of the conveyance roller pair in the sheet conveyance direction and draws the sheet into the second conveyance path. And
An insertion sheet detection unit that is disposed upstream of the drawing unit in the sheet conveyance direction and outputs a detection signal according to the position of the sheet inserted into the second conveyance path;
The conveying roller pair and the pulling-in means are driven based on a detection signal output from the insertion sheet detecting means.
The sheet conveying apparatus according to claim 1. The feeding unit is configured to feed a sheet stacked on the sheet stacking unit or to feed a sheet conveyed by the conveying unit;
A separation unit that separates the sheets fed or conveyed by the feeding unit one by one,
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The feeding unit is supported so as to be able to contact and separate from the sheets stacked on the sheet stacking unit.
The sheet conveying apparatus according to claim 8. The sheet stacking unit includes a stacking main body part, and a stacking part that stacks sheets and is supported by the stacking main body part so as to be movable up and down.
The feeding unit is movable with respect to the loading main body unit,
The sheet conveying apparatus according to claim 9. The sheet stacking unit includes a stacking main body part, and a stacking part that stacks sheets and is supported by the stacking main body part so as to be movable up and down.
The feeding unit is immovable with respect to the stacking main body unit.
The sheet conveying apparatus according to claim 9. The second transport path is disposed above the sheet stacking unit.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. A sheet is manually inserted into the second conveyance path.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The sheet detecting means includes a moving unit that moves when pressed by a sheet at a protruding position protruding into the second conveyance path, and a detecting unit that outputs a detection signal according to the position of the moving unit.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The sheet stacking means is a cassette that can be inserted into and removed from the apparatus main body,
A guide member which is provided above the cassette and forms a part of the second conveyance path and is supported so as to be detachable or movable with respect to the apparatus main body;
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. A sheet conveying device according to any one of claims 1 to 15,
Image forming means for forming an image on a sheet conveyed by the sheet conveying device;
An image forming apparatus.

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