Sheet Feeding Device

Abstract

To provide such a configuration as to suppress generation of a jam in a sheet.SOLUTION: A pickup roller 231 feeds a sheet loaded on a loading tray. A first conveyance roller 232 conveys the sheet fed by the pickup roller 231, and a second conveyance roller 235 is provided on the downstream in the sheet conveyance direction of the first conveyance roller 232. The pickup roller 231 is moved up and down, and the first conveyance roller 232 is driven in a direction conveying the sheet when the pickup roller 231 is moved down. The second conveyance roller 235 is rotated so as to convey the sheet conveyed by the first conveyance roller 232 to the downstream in the conveyance direction while the pickup roller 231 is moved down.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a sheet feeding device that feeds a sheet. [Background technology]

[0002] A sheet feeding device that feeds sheets feeds sheets on a stacking tray using a pickup roller and transports them using a transport roller. As such a sheet feeding device, there is a configuration in which the pickup roller is raised and lowered relative to the sheets on the stacking tray. For example, in an automatic document feeder, a configuration in which the pickup roller is raised and lowered using a drive motor that drives the pickup roller and the transport roller is known (for example, Patent Document 1).

[0003] In the configuration described in Patent Document 1, the reverse rotation of the drive motor is configured so that it is not transmitted to the pickup roller and the conveying roller by the action of a one-way clutch. The forward rotation of the drive motor rotates the pickup roller and the conveying roller in the sheet conveying direction and lowers the pickup roller, and the reverse rotation raises the pickup roller. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-303610 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the configuration described in the above-mentioned Patent Document 1, in which the conveying roller is driven in a direction to convey the sheet when the pickup roller descends, there is a risk that the sheet will be conveyed by the conveying roller when the pickup roller descends.

[0006] There is a second transport roller downstream of the transport roller (first transport roller) that transports the sheet further downstream, but usually, this second transport roller is not driven when the pickup roller descends. Therefore, when the pickup roller descends, the sheet transported by the first transport roller may hit the second transport roller, causing the leading edge of the sheet to be crushed or damaged. As a result, there is a risk of the sheet jamming in the transport path.

[0007] An object of the present invention is to provide a configuration capable of suppressing the occurrence of sheet jams. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a storage unit that is movable between a drawn-out position where it is drawn out relative to a main body of an apparatus and a mounted position where it is mounted to the main body of the apparatus; a stacking tray on which sheets are stacked, a feed roller that feeds the sheets stacked on the stacking tray, a first conveying roller that conveys the sheets fed by the feed roller, and a second conveying roller provided downstream of the first conveying roller in a sheet conveying direction; The feed roller is raised before the storage case moves to the pull-out position, and the feed roller is lowered after the storage case moves to the mounting position. and a driving means for driving the first conveying roller to drive the feeding roller by the driving means. During the descent the second conveying roller rotates in a direction in which the sheet is conveyed to the downstream side of the sheet conveying direction while the feed roller is lowered, and the second conveying roller rotates in a direction in which the sheet conveyed by the first conveying roller is conveyed to the downstream side of the sheet conveying direction while the feed roller is lowered. A sheet feeding device . Effect of the Invention

[0009] According to the present invention, the occurrence of sheet jams can be suppressed. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an image forming system according to an embodiment. [Diagram 2] FIG. 2 is a front view of the multi-tier storage device according to the embodiment. [Diagram 3] FIG. 2 is a plan view showing the multi-tier storage device according to the embodiment with the storage compartments pulled out. [Figure 4]FIG. 2 is a side view showing the multi-tier storage device according to the embodiment with the storage compartments pulled out. [Diagram 5] FIG. 1 is a schematic diagram of a storage unit according to an embodiment. [Figure 6] FIG. 4 is a diagram showing a driving configuration of a sheet feeding unit according to the embodiment. [Figure 7] FIG. 4 is a block diagram of a control configuration of the multi-tier storage device according to the embodiment. [Figure 8] 1A and 1B are diagrams showing, in an embodiment, (a) a state in which the pickup roller starts to descend when there is a hanging sheet, (b) a state in which the hanging sheet is transported when the pickup roller 231 descends, and (c) a state at the end of the descent of the pickup roller. [Figure 9] 11A and 11B are diagrams illustrating an example of performing skew correction of a sheet while a pickup roller 231 is descending according to the embodiment. [Figure 10] 5A shows a state in which the stack tray is raised after the pickup roller has been lowered, and FIG. 5B shows a state in which sheet feeding has started, according to the embodiment. [Figure 11] 5A and 5B are diagrams illustrating detection states of the empty sensor according to the embodiment when there is no sheet on the stacking tray and when there is a sheet on the stacking tray. [Figure 12] 11 is a flowchart for determining whether or not a job can be performed with respect to sheet detection accompanying a downward movement of a pickup roller according to the embodiment. [Figure 13] 10 is a flowchart illustrating the operation of a sheet feeding unit and a stacking tray when the storage cabinet is opened according to the embodiment. [Figure 14] 11 is a flowchart illustrating the operation of a sheet feeding unit and a stacking tray when the storage cabinet is closed according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The embodiment will be described with reference to Figures 1 to 14. First, the image forming system of the present embodiment will be described with reference to Figure 1.

[0012] [Image formation system] 1 is a cross-sectional view showing an example of an image forming system including a multi-tier storage device and an image forming apparatus according to the present embodiment. In the following description, an image forming apparatus having an image forming section will be described by taking an electrophotographic laser printer system (hereinafter simply referred to as a printer) as an example. The image forming apparatus constituting the image forming system may be a copier, a facsimile, a multifunction machine, etc., in addition to a printer. The image forming apparatus may also be configured to be an inkjet type or other type, regardless of the electrophotographic type.

[0013] The image forming system 1000 of this embodiment includes an image forming apparatus 100, a multi-tiered storage apparatus 200 as a sheet feeding apparatus connected to the image forming apparatus 100, and a feed deck 500. As described later in detail, the multi-tiered storage apparatus 200 has a plurality of storage chambers each capable of storing a plurality of sheets, and can feed sheets from each storage chamber to the image forming apparatus 100. The feed deck 500 also has a storage chamber capable of storing a plurality of sheets, and is disposed upstream of the multi-tiered storage apparatus 200 in terms of the sheet conveying direction. The sheets fed from the feed deck 500 are conveyed to the image forming apparatus 100 via a relay conveying device 400 provided in the multi-tiered storage apparatus 200. Examples of the sheets include plain paper, thin paper, thick paper, plastic sheets, and the like. In the following, the downstream side of the sheet conveying direction may be simply referred to as the "downstream side", and the upstream side of the sheet conveying direction may be simply referred to as the "upstream side".

[0014] The image forming apparatus 100 forms a toner image (image) on a sheet in response to an image signal from a document reading device 102 connected to the image forming apparatus main body 101 or a host device such as a personal computer communicably connected to the image forming apparatus main body 101. In this embodiment, the document reading device 102 is disposed on the upper side of the image forming apparatus main body 101.

[0015] When reading an original, the original reading device 102 irradiates light from a scanning optical system light source onto an original placed on a platen glass 103, and the reflected light is input to a CCD to read the original image. The original reading device 102 also includes an automatic document feeder (ADF) 104, and the original placed on a tray 105 can be automatically conveyed by the ADF 104 to a reading section of the original reading device 102 to read the original image. The read original image is then converted into an electrical signal and transmitted to a laser scanner 113 of an image forming section 110, which will be described later. Note that the laser scanner 113 may also receive image data transmitted from a personal computer or the like, as described above.

[0016] Image forming apparatus 100 includes image forming section 110, a plurality of sheet feeding devices 120, sheet conveying device 130, etc. Each section of image forming apparatus 100 is controlled by control section 140. Control section 140 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU controls each section while reading a program corresponding to a control procedure stored in the ROM. In addition, working data and input data are stored in the RAM, and the CPU performs control by referring to the data stored in the RAM based on the above-mentioned programs, etc.

[0017] Each of the plurality of sheet feeding devices 120 includes a cassette 121 for storing sheets S, a pickup roller 122, and a separation conveying roller pair 125 consisting of a feed roller 123 and a retard roller 124. The sheets S stored in the cassette 121 are separated and fed one by one by the pickup roller 122 and the separation conveying roller pair 125 which rotate by moving up and down at a predetermined timing.

[0018] The sheet conveying device 130 includes a conveying roller pair 131 and a registration roller pair 133. The sheet S fed from the sheet feeding device 120 is passed through a sheet conveying path 134 by the conveying roller pair 131, and then guided to the registration roller pair 133. Thereafter, the sheet S is sent to the image forming unit 110 by the registration roller pair 133 at a predetermined timing.

[0019] Incidentally, a sheet transported from a multi-tier storage device 200 or a feeding deck 500 described later via a pair of transport rollers 201 is transported into the image forming apparatus 100 via a connection path 202 with the image forming apparatus 100. Then, the sheet transported from the multi-tier storage device 200 or the feeding deck 500 into the image forming apparatus 100 is sent into the image forming section 110 at a predetermined timing via a pair of registration rollers 133, similar to the sheet transported from the sheet feeding device 120 in the image forming apparatus 100.

[0020] The image forming unit 110 includes a photosensitive drum 111, a charger 112, a laser scanner 113, a developing unit 114, a transfer device 115, a cleaner 117, and the like. During image formation, the photosensitive drum 111 is rotationally driven, and first, the surface of the photosensitive drum 111 is uniformly charged by the charger 112. Then, the charged photosensitive drum 111 is irradiated with laser light from a laser scanner 113 that is emitted in response to an image signal, thereby forming an electrostatic latent image on the photosensitive drum 111. Furthermore, the electrostatic latent image thus formed on the photosensitive drum 111 is then visualized as a toner image by the developing unit 114.

[0021] Thereafter, the toner image on the photosensitive drum 111 is transferred to the sheet S by the transfer device 115 in the transfer section 116. Furthermore, the sheet S onto which the toner image has been transferred in this manner is conveyed to the fixing device 150 where the toner image is fixed, and thereafter, the sheet S is discharged by the discharge rollers 151 onto a discharge tray 152 outside the apparatus.

[0022] When a toner image is formed on the back side of the sheet S, the sheet S discharged from the fixing device 150 is conveyed to a reversing conveying path 160. Then, in a state where the sheet S is turned over by the reversing conveying path 160, it is conveyed again to the transfer unit 116 of the image forming unit 110. The sheet S with the toner image transferred to the back side is conveyed to the fixing device 150, where the toner image is fixed, and then the sheet S is discharged to a discharge tray 152 by a discharge roller 151. Note that any residual toner remaining on the photosensitive drum 111 after the transfer is removed by a cleaner 117.

[0023] Although the above-described image forming system 1000 includes the multi-tier storage device 200 and the feeding deck 500 as a sheet feeding device, it may include only the multi-tier storage device 200 or only the feeding deck 500. Furthermore, it may include another feeding deck, etc.

[0024] [Multi-tier storage device] An overview of the multitier storage equipment 200 will be described with reference to Figures 1 to 5. The multitier storage equipment 200 includes a plurality of storage cabinets 210, an intermediary transport device 400, etc. In this embodiment, three storage cabinets 210 are arranged vertically in three tiers, and the intermediary transport device 400 is disposed between the bottom storage cabinet 210 and the second storage cabinet 210 from the top.

[0025] The sheet fed from the topmost storage 210 is transported to a transport path 212, the sheet fed from the second topmost storage 210 is transported to a transport path 213, and the sheet fed from the bottommost storage 210 is transported to a transport path 214. The sheet transported from the relay transport device 400 is transported to a transport path 215. The transport path 213 merges with the transport path 212 midway. The transport paths 212, 214, and 215 merge at a junction 216, and the sheet is transported to the transport roller pair 201 via the transport path 217 and then transported to the image forming device 100 via the connection path 202.

[0026] Further, a multi-feed detection sensor for detecting multi-feeding of sheets is disposed on the conveying path 212 after merging with the conveying path 213, the relay conveying device 400, and the conveying path 214. A sheet for which a multi-feed is detected by the multi-feed detection sensor is conveyed to the conveying path 217. A multi-feed sheet storage section (escape tray) 218 ​​for storing a sheet for which a multi-feed is detected is disposed below the conveying path 217. A sheet for which a multi-feed is detected and conveyed to the conveying path 217 is conveyed to the multi-feed sheet storage section by switching the conveying path by a switching member 219 provided on the conveying path 217.

[0027] 2 is a front view of the multitier storage device 200. As described above, the multitier storage device 200 has multiple storage cabinets 210, each capable of storing multiple sheets. The storage cabinets 210 are arranged in multiple tiers in the vertical direction, and can be pulled out and inserted into the housing (device body) 204 of the multitier storage device 200. The storage cabinets 210 have the same basic configuration, except that they can store different numbers of sheets. However, there are cases in which the storage cabinets 210 can store the same number of sheets.

[0028] Sheets fed from each storage 210 are transported to a connection path 202 (see FIG. 1) via transport paths 212, 213, and 214. In addition, each part of the multi-tier storage device 200 is controlled by a control unit 203 (see FIG. 1). As shown in FIG. 7, which will be described later, the control unit 203 has a central processing unit (CPU) 203a, a read only memory (ROM) 203b, and a random access memory (RAM) 203c. In addition, the control unit 203 can communicate with a control unit 140 of the image forming apparatus 100, and controls the timing of sheet feeding and the like by communicating with the control unit 140.

[0029] The multi-level storage device 200 has a pull-out button (operation unit) 205 as an operating means for pulling out the storage 210. The pull-out button 205 is provided on the front surface of each storage 210. For example, when an operator presses the pull-out button 205, a pull-out solenoid 205a (see FIG. 7) operates, a locking mechanism that has locked the storage 210 in the mounting position is released, and the storage 210 is pushed out of the housing 204 by a spring (not shown). This allows the operator to pull out the storage 210 to a position where the sheet can be stored, as shown in FIGS. 3 and 4. Note that the configuration may be such that, when the pull-out button 205 is pressed, the storage 210 is automatically moved to a position where the sheet can be stored by a motor or the like.

[0030] 3 to 5, the storage 210 has a sheet storage section 220 capable of storing sheets S, and a sheet feeding section 230 that feeds sheets S from the sheet storage section 220 toward the image forming apparatus 100. As shown in Fig. 4, the sheet storage section 220 has a stacking tray 221 on which the sheets S are stacked, an abutment section 222, a trailing end regulating plate 223, a side regulating plate 224, etc. As shown in Fig. 5, the stacking tray 221 can be raised and lowered in the vertical direction by a lifting mechanism 226 serving as a lifting means.

[0031] The lifting mechanism 226 as a lifting means has a lifting motor 227 as a drive source, a drive pulley 228a, a guide pulley 228b, a wire 228c, and a rail 229. The wire 228c is connected to the stacking tray 221 and the drive pulley 228a via the guide pulley 228b. The stacking tray 221 is supported so as to be movable in the up and down direction along the rail 229. The drive pulley 228a is driven to rotate by the lifting motor 227, whereby the wire 228c is wound or pulled out, and the movement of the wire 228c is transmitted to the stacking tray 221 via the guide pulley 228b. As a result, the stacking tray 221 is lifted or lowered along the rail 229.

[0032] In this embodiment, the stacking tray 221 is lowered to a predetermined stacking position when the sheets S are stacked, and is gradually lowered when, for example, the storage case 210 is pulled out and the sheets are stacked. Then, when the storage case 210 is attached and the sheets S stacked on the stacking tray 221 are fed, the stacking tray 221 is gradually raised. The predetermined stacking position is also called an intermediate position, and the stacking tray 221 is located at a middle position above the lowest position of the storage case 210. This is because if the stacking tray 221 is lowered to the lowest position when storing the sheets, it is difficult for a user to stack the sheets on the stacking tray 221. For this reason, when storing the sheets, the descent of the stacking tray 221 is stopped at the intermediate position, and the stacking tray 221 is lowered every time a sheet is stacked.

[0033] Further, the lift motor 227 is provided in the storage 210. In this embodiment, the lift motor 227 is provided in the storage 210, and power can be supplied to the lift motor 227 from the housing 204 side via a cable.

[0034] As shown in FIG. 4, the abutting portion 222 is disposed downstream in the sheet conveying direction in the storage space 225 in which the sheets are stored, and is abutted against the downstream end (leading end) in the conveying direction of the sheets stacked on the stacking tray 221. The trailing end regulating plate 223 is disposed upstream in the sheet conveying direction in the storage space 225, and is abutted against the upstream end (rear end) in the conveying direction of the sheets stacked on the stacking tray 221, thereby regulating the trailing end position of the sheet. The trailing end regulating plate 223 is movable in the sheet conveying direction, and is capable of adjusting the trailing end regulating position of the sheet according to the sheet size. The side regulating plates 224 are disposed on both sides in the width direction perpendicular to the sheet conveying direction of the storage space 225, and regulate the positions of both ends in the width direction of the sheet. The side regulating plates 224 are movable in the width direction, and is capable of adjusting the regulating position of the sheet in the width direction according to the sheet size.

[0035] 5, the sheet feeding section 230 as a feeding section includes a pickup roller 231 as a feeding means and a feeding roller, a separation conveying roller pair 234 composed of a first conveying roller (conveying roller) 232 and a retard roller 233, and a conveying roller pair (registration roller pair) 237 composed of a second conveying roller 235 and an opposing roller 236. The pickup roller 231 and the separation conveying roller pair 234 are disposed at the downstream end in the sheet conveying direction above the storage space 225 and at approximately the center in the width direction, as shown in FIG.

[0036] Pickup roller (feed roller) 231 is provided in storage 210 and feeds (feeds) the sheets stored in storage 210. Specifically, pickup roller 231 is provided above stacking tray 221 and abuts against the top sheet of sheets S stacked on the elevated stacking tray 221 to feed it. For this purpose, as shown in Fig. 5, pickup roller 231 is disposed near the leading end of sheet S in the sheet conveying direction (arrow α direction) so as to be able to press against the top sheet on stacking tray 221 with an appropriate force. Then, it is rotated by the drive of feed motor 301 as a drive source to feed the top sheet in the arrow α direction.

[0037] When two or more overlapping sheets are fed from the pickup roller 231, the separation conveying roller pair 234 separates the overlapping sheets and conveys only one sheet. That is, the first conveying roller 232 of the separation conveying roller pair 234 rotates in a direction to convey the sheet in the direction of the arrow α by the drive of the feeding motor 301, and conveys the sheet fed from the pickup roller 231. On the other hand, the retard roller 233 rotates in a direction opposite to that of the first conveying roller 232, and pushes back the sheets other than the topmost sheet among the two or more sheets fed from the pickup roller 231 to the stacking tray 221 side. Note that the retard roller 233 has a built-in torque limiter (not shown), and when only one sheet is fed to the separation conveying roller pair 234, the retard roller 233 rotates together with the sheet conveyed by the first conveying roller 232.

[0038] The sheet separated and conveyed by the pair of separation conveying rollers 234 is conveyed to a conveying path in the multi-tier storage device 200 by a second conveying roller 235 rotated by a conveying motor 235a. That is, the sheet in the topmost storage 210 in Fig. 1 is conveyed to a conveying path 212, the sheet in the second storage 210 to a conveying path 213, and the sheet in the bottommost storage 210 to a conveying path 214. The sheet is then conveyed from these conveying paths to the image forming device 100 via the connection path 202 (Fig. 1) as described above.

[0039] In the present embodiment, the sheet feeding unit 230 is provided in the storage case 210 as described above. Therefore, when the storage case 210 is pulled out and inserted into the housing 204 of the multi-tier storage device 200, the sheet feeding unit 230 moves together with the storage case 210. In other words, the sheet feeding unit 230 is configured to be pulled out and attached to the housing 204, which serves as the device main body, simultaneously with the storage case 210. In this manner, by configuring the sheet feeding unit 230 to be pulled out together with the storage case 210, maintenance such as replacement of the rollers of the sheet feeding unit 230 is facilitated.

[0040] [Drive mechanism] The first conveying roller 232 and the pickup roller 231 constituting the above-mentioned sheet feeding unit 230 are rotated by a feeding motor 301, and the second conveying roller 235 is rotated by a feeding motor 235a. The pickup roller 231 is raised and lowered in the vertical direction by the driving of the feeding motor 301.

[0041] Hereinafter, a drive transmission mechanism (feed drive unit) 300 for the first conveyor roller 232 and the pickup roller 231, and a drive transmission mechanism (conveyor drive unit) 600 for the second conveyor roller 235 will be described with reference to Fig. 6. Note that Fig. 6 shows only the drive transmission path from the feed motor 301 to the pickup roller 231 and the drive transmission path from the conveyor motor 235a to the second conveyor roller 235.

[0042] The feed motor 301 and the transport motor 235a as drive motors are, for example, pulse motors, and are provided in the housing 204 (see FIG. 4, etc.) of the multi-tier storage device 200. For this reason, the drive transmission mechanism 300 has a coupling 302 as a connection means so that when the storage 210 is pulled out from the housing 204, the drive transmission path from the feed motor 301 to the first transport roller 232 is separated midway. Similarly, the drive transmission mechanism 600 has a coupling 601 as a connection means so that when the storage 210 is pulled out from the housing 204, the drive transmission path from the transport motor 235a to the second transport roller 235 is separated midway.

[0043] That is, the drive transmission mechanism 300 has a motor-side drive transmission mechanism 310 from the feed motor 301 to the coupling 302, and a roller-side drive transmission mechanism 320 from the coupling 302 to the pickup roller 231. The coupling 302 connects the feed motor 301 and the pickup roller 231 so as to be able to transmit drive power when the storage case 210 is inserted into the housing 204, and releases the drive connection between the feed motor 301 and the pickup roller 231 when the storage case 210 is pulled out.

[0044] Similarly, the drive transmission mechanism 600 has a motor-side drive transmission mechanism 610 from the transport motor 235a to the coupling 601, and a roller-side drive transmission mechanism 620 from the coupling 601 to the second transport roller 235. The coupling 601 connects the transport motor 235a and the second transport roller 235 so as to be able to transmit drive power when the storage case 210 is inserted into the housing 204, and releases the drive connection between the transport motor 235a and the second transport roller 235 when the storage case 210 is pulled out.

[0045] The drive transmission mechanism 300 as a drive means has a feed motor 301 capable of rotating in both directions, which serves as a drive motor for lowering the pickup roller 231 by rotating in one direction (forward rotation) and rotating the first conveying roller 232 in the sheet conveying direction. The forward rotation drive of the feed motor 301 is transmitted from a pulley P1 to a pulley P2 via a timing belt T1. The drive drive of the pulley P2 is transmitted in this order to a gear Z1, a gear Z2, and a gear Z3 attached to the drive shaft 232a of the first conveying roller 232 via a coupling 302, so that the first conveying roller 232 rotates in the sheet conveying direction. A pulley P3 is provided on the drive shaft 232a of the first conveying roller 232, and the drive drive is also transmitted to the pickup roller 231 via a timing belt T2 stretched between the pulley P3 and a pulley P4 provided on the drive shaft 231a of the pickup roller 231.

[0046] Moreover, one end side of lifting arms 350a, 350b as a support member supporting the pickup roller 231 is attached to the drive shaft 232a of the first conveyor roller 232, and the rotation of the drive shaft 232a in the conveying direction (the forward drive of the feed motor 301) rotates the lifting arms 350a, 350b to lower the pickup roller 231. When the pickup roller 231 abuts against a sheet on the stacking tray 221, the drive shaft 232a of the first conveyor roller 232 rotates idly relative to the lifting arms 350a, 350b due to the action of the spring clutches CL1 and CL2.

[0047] Meanwhile, the reverse drive of the feed motor 301 is also transmitted to the drive shaft 232a of the first conveyor roller 232, and rotates the lifting arms 350a, 350b to lift the pickup roller 231. At this time, the first conveyor roller 232 does not rotate due to the action of a one-way clutch OW1 provided therein. The lifting arms 350a, 350b that have been raised come into contact with a regulating member (not shown), and the lifting arms 350a, 350b are configured to rotate freely relative to the drive shaft 232a of the first conveyor roller 232 due to the action of the spring clutch CL3.

[0048] In this manner, the pickup roller 231 is raised and lowered by rotating the lifting arms 350a and 350b in response to the forward and reverse rotation of the feed motor 301. As a result, the drive transmission mechanism 300 as a drive means raises and lowers the pickup roller 231 to a lower position for contacting the sheet on the stacking tray 221 and an upper position above the lower position for placing the sheet on the stacking tray 221.

[0049] Specifically, as shown in FIG. 8(a) to be described later, when the feed motor 301 is rotated forward with the pickup roller 231 in the upper position, the lifting arms 350a and 350b rotate toward (below) the upper surface of the sheets on the stacking tray 221 to lower the pickup roller 231 (state in FIG. 8(c) to be described later). Then, by lifting the stacking tray 221 by the lifting mechanism 226 as described above, the uppermost sheet on the stacking tray 221 comes into contact with the pickup roller 231 (state in FIG. 10(a) to be described later). This generates a predetermined torque on the drive shaft 232a, which causes the spring clutches CL1 and CL2 to act, causing the lifting arms 350a and 350b to rotate idly relative to the drive shaft 232a, and the pickup roller 231 maintains a state of contacting the upper surface of the sheet.

[0050] Also, when the feed motor 301 is rotated in the reverse direction, the drive shaft 232a rotates in the opposite direction to the conveying direction, and the lifting arms 350a and 350b rotate in the direction (upward) away from the sheets on the stacking tray 221 with the reverse rotation of the drive shaft 232a, thereby lifting the pickup roller 231. Then, a part of the lifting arms 350a and 350b abuts against a regulating member (not shown) and stops rotating. This position is the upper position (retracted position). As a result, a predetermined torque is generated in the drive shaft 232a of the first conveying roller 232, the spring clutches CL1 and CL2 act, and the lifting arms 350a and 350b rotate idly relative to the drive shaft 232a. Then, the pickup roller 231 is held in the upper position.

[0051] Meanwhile, in the drive transmission mechanism 600, the rotational drive of the conveying motor 235a is transmitted from a pulley P5 to a pulley P6 via a timing belt T3. The drive of the pulley P6 is transmitted in this order to a gear Z4 via a coupling 601 and then to a gear Z5 attached to the drive shaft 235b of the second conveying roller 235, so that the second conveying roller 235 rotates in the sheet conveying direction. A one-way clutch OW2 is disposed inside the gear Z5, so that the second conveying roller 235 rotates idly when a sheet held between the pair of conveying rollers 237 is pulled out during jam clearance.

[0052] [Control configuration] Next, the control configuration of the multi-tier storage device 200 of this embodiment will be described using FIG. 7 with reference to FIG. 5. As described above, the control unit 203 has a CPU 203a, a ROM 203b, and a RAM 203c. The above-mentioned feed motor 301, the transport motor 235a, and the lift motor 227 are connected to the control unit 203 and are each controlled by the control unit 203. When the pull-out button 205 is pressed, the control unit 203 controls the pull-out solenoid 205a as described above to make it possible to pull out the storage cabinet 210. The multi-tier storage device 200 also has a display unit 206 as a notification means, and the control unit 203 can notify various information by the display unit 206.

[0053] The display unit 206 is, for example, an LED, and when the storage 210 runs out of sheets or when a sheet jams on the way of the transport path, the LED is turned on to notify an operator such as a user. In this embodiment, the display unit 206 is a green and red LED provided near, for example, the pull-out button 205 of each storage 210, and when the green LED is turned on, it may indicate that there is a sheet in that storage 210, and when the red LED is turned on, it may indicate that there is no sheet in that storage 210. In addition to or instead of such an LED, the display unit may be one capable of displaying an image such as a liquid crystal screen, and the installation location is not limited to the vicinity of the pull-out button 205, and may be one location instead of being provided for each storage 210.

[0054] Furthermore, the multi-tier storage device 200 is equipped with various sensors such as an upper surface detection sensor 700, a lower limit detection sensor 701, an empty sensor 702, an installation sensor 703, a first sheet detection sensor 704, and a second sheet detection sensor 705. The upper surface detection sensor 700 is disposed near the pickup roller 231 as shown in Fig. 5, and detects the uppermost sheet stacked on the stacking tray 221 by coming into contact with the sheet. When the upper surface detection sensor 700 detects a sheet, the control unit 203 is in a state in which the sheet can be fed by the pickup roller 231.

[0055] The lower limit detection sensor 701 detects the lower limit position of the stacking tray 221. As described above, the stacking tray 221 gradually descends when sheets are stacked on it. When the lower limit detection sensor 701 detects that the stacking tray 221 has reached the lower limit position, the control unit 203 stops the downward movement of the stacking tray 221.

[0056] The empty sensor 702 as the first detection means detects a sheet on the stacking tray 221. In this embodiment, as shown in FIG. 5 and FIGS. 11(a) and (b) described later, it is located above the stacking tray 221 and detects the presence or absence of a sheet on the stacking tray 221. The empty sensor 702 detects the presence or absence of a sheet at a position upstream away from the pickup roller 231. When the control unit 203 determines that there is no sheet on the stacking tray 221 (on the stacking tray) (i.e., there is no sheet in the storage 210) based on the detection result of the empty sensor 702, it notifies the fact by the display unit 206 as described above. A detailed configuration of the empty sensor 702 will be described later.

[0057] The mounting sensor 703 detects whether the storage 210 is mounted at the mounting position of the housing 204. When the mounting sensor 703 detects that the storage 210 is mounted in the housing 204, the control unit 203 moves the pickup roller 231 to a lower position, as described below. The first sheet detection sensor 704 is disposed downstream near the first conveying roller 232, and detects the presence or absence of a sheet. Specifically, it detects the leading edge of the sheet separated and conveyed by the separation conveying roller pair 234.

[0058] The second sheet detection sensor 705 as the detection means and the second detection means is a sensor that detects a sheet between the first conveyance roller 232 and the second conveyance roller 235, and is located downstream of the first sheet detection sensor 704. When the sheet is detected by the second sheet detection sensor 705, the control unit 203 determines that the sheet is present between the first conveyance roller 232 and the second conveyance roller 235. The sensors that detect the sheets are disposed at a plurality of positions on the conveyance path of the multi-tier storage device 200, and detect the presence or absence of a sheet at each position. The control unit 203 can detect a sheet jam based on information from these sheet detection sensors, and can display the position where the jam has occurred on a display screen provided in the image forming system 1000, such as the operation panel of the image forming device 100 to which the multi-tier storage device 200 is connected, for example.

[0059] [Storage drawer and installation operations] Next, the operation of pulling out storage 210 from housing 204 will be described. First, when control unit 203 detects that pull-out button 205 (see FIG. 2, etc.) is pressed, it rotates feed motor 301 in the reverse direction. As a result, pickup roller 231 starts to rotate upward about drive shaft 232a of first conveyor roller 232 as a fulcrum, and moves to an upper position.

[0060] In this embodiment, as shown in Fig. 8(a), a flag 351 is provided on a part of the lift arm 350a (or 350b) supporting the pickup roller 231, and when the pickup roller 231 moves to the raised position, the flag 351 enters between the light emitting portion and the light receiving portion of the photointerrupter 352, so that the control unit 203 knows that the pickup roller 231 has moved to the raised position. Then, when the control unit 203 detects the flag 351 by the photointerrupter 352, the control unit 203 stops driving the feed motor 301. Note that the control unit 203 may stop driving the feed motor 301 when a certain time has elapsed from when the pickup roller 231 starts to rise to the raised position, thereby stopping the pickup roller 231 at the raised position.

[0061] 8A, in the upper position, the pickup roller 231 moves to a position where a part of its outer periphery is directly above the first conveyor roller 232. When the pickup roller 231 moves to the upper position, the control unit 203 unlocks the storage case 210. When the storage case 210 is unlocked, the operator can manually pull out the storage case 210 including the sheet feeding unit 230.

[0062] The upper position is a position where sheets can be stored in the storage case 210, and is a position where the pickup roller 231 is retracted from the storage space 225 further than the lower position when storing sheets in the sheet storage section 220. That is, in this embodiment, the sheet feeding section 230 is provided in the storage case 210, and is drawn out together with the storage case 210. At this time, if the pickup roller 231 is in the lower position, the pickup roller 231 and the sheets are likely to interfere with each other when loading the sheets onto the loading tray 221, making it difficult to load the sheets. For this reason, in this embodiment, when the storage case 210 is drawn out, the pickup roller 231 is moved to the upper position where it is unlikely to interfere with the loading of sheets.

[0063] Next, the operation of the sheet feeding unit 230 when the storage 210 is inserted into the mounting position in the housing 204 will be described. First, when the mounting sensor 703 detects that the storage 210 is mounted in the mounting position, the control unit 203 rotates the feed motor 301 forward. As a result, the pickup roller 231 starts to rotate downward about the drive shaft 232a of the first conveying roller 232 as a fulcrum, and moves from the state of FIG. 8(a) to the state of FIG. 8(b) and FIG. 8(c) and is located at the lower position. Thus, in this embodiment, the drive transmission mechanism 300 raises the pickup roller 231 to the upper position before the storage 210 is drawn out from the mounting position and reaches the drawn out position, and lowers the pickup roller 231 to the lower position after the storage 210 moves to the mounting position. The amount of movement of pickup roller 231 from the upper position to the lower position is the amount by which a virtual line passing through the center of rotation of first conveying roller 232 and the center of rotation of pickup roller 231 rotates by 60° or more, preferably 80° or more, and more preferably 90° or more around the center of rotation of first conveying roller 232.

[0064] [Sagging sheet] Here, when the sheet feeding section 230 is performing a sheet feeding operation, multiple sheets may be fed. At this time, the multiple sheets are separated by the separation conveying roller pair 234, but the separated sheets may remain nipped by the separation conveying roller pair 234 when the sheet feeding operation is completed. In this case, the sheet hangs down so as to straddle the separation conveying roller pair 234 and the storage space 225. Hereinafter, such a sheet is referred to as a hanging sheet.

[0065] When the drawer operation and the mounting operation of the storage 210 are performed as described above with the hanging sheet in this manner, the following problem may occur. That is, when the operator operates the drawer button 205 to draw out the storage 210 with the hanging sheet, the pickup roller 231 moves to the upper position as described above. At this time, the feed motor 301 is rotated in reverse, and the first conveyor roller 232 constituting the separation conveyor roller pair 234 does not rotate due to the one-way clutch OW1. For this reason, the storage 210 is drawn out with the hanging sheet in place.

[0066] Next, when the operator mounts the storage 210 to the mounting position with the hanging sheet therein, the pickup roller 231 moves from the upper position to the lower position. At this time, the feed motor 301 rotates forward, and the pickup roller 231 and the first conveying roller 232 rotate in the direction to convey the sheet. Therefore, as shown in FIG. 8(a), the hanging sheet S1 held by the separation conveying roller pair 234 is conveyed further downstream by the downward movement of the pickup roller 231, as shown in FIG. 8(b).

[0067] [Effective use of hanging sheets] As described above, there is a second sheet detection sensor 705 downstream of the first conveying roller 232, and the control unit 203 as a determination unit determines whether or not a sheet has jammed based on the detection state of the second sheet detection sensor 705, and when it determines that a sheet has jammed, stops the sheet feeding operation by the sheet feeding unit 230. Furthermore, when the control unit 203 determines that a sheet has jammed, as described above, it causes the display unit 206 to notify that effect.

[0068] Here, as described above, the hanging sheet S1 conveyed by the first conveying roller 232 in association with the downward movement of the pickup roller 231 may be detected by the second sheet detection sensor 705. This hanging sheet S1 is not a jammed sheet, but a sheet (valid sheet) that can be used for image formation. Therefore, when such a valid sheet is detected by the second sheet detection sensor 705, if it is uniformly determined that there is a jam, this sheet cannot be used effectively. Furthermore, if it is determined that there is a jam, sheet feeding cannot be resumed unless this sheet is removed, which reduces productivity.

[0069] Therefore, in this embodiment, the control unit 203 does not treat a sheet detected by the second sheet detection sensor 705 while the pickup roller 231 is descending as a jammed sheet. In other words, it is determined that there is no jam. Therefore, when the hanging sheet S1 described above is detected by the second sheet detection sensor 705, the display unit 206 is not notified that there is a jam.

[0070] Furthermore, the control unit 203 judges whether a sheet is jammed and whether a sheet feeding operation is possible or not according to the sheet detection status of the second sheet detection sensor 705 at the time when the control unit 203 receives an instruction to start feeding the sheet. That is, if the control unit 203 judges that a jam is present, the feeding operation is disabled, and if the control unit 203 judges that no jam is present, the feeding operation is enabled. Specifically, when the control unit 203 receives an instruction to start feeding, the control unit 203 checks the status of the sheet detection sensors arranged on each transport path of the multi-tier storage device 200, and if a sheet is detected by any of the sheet detection sensors, it judges that a sheet jam has occurred at that location, displays that fact on the display unit 206, and stops the sheet feeding operation.

[0071] However, control unit 203 monitors the detection status of second sheet detection sensor 705 during the downward movement of pickup roller 231. Then, if a sheet is detected by second sheet detection sensor 705 during the downward movement of pickup roller 231, control unit 203 does not treat the sheet as a jammed sheet even if the sheet is detected by second sheet detection sensor 705 at the time when a feeding start instruction is received. This reduces the frequency of jams, suppresses a decrease in productivity, and allows for effective use of sheets.

[0072] On the other hand, as described above, there are cases where the hanging sheet S1 transported by the downward movement of the pickup roller 231 stops in a state straddling the storage 210 and the transport path of the housing 204. In such a case, if the operator operates the pull-out button 205 to pull out the storage 210, there is a risk that the hanging sheet S1 may be damaged by being torn or twisted. Therefore, in this embodiment, the control unit 203 does not allow the storage 210 to be pulled out if the second sheet detection sensor 705 detects a sheet when the pull-out button 205 is operated.

[0073] Specifically, when the pull-out button 205 is pressed, the control unit 203 checks the detection state of the second sheet detection sensor 705, and if a sheet is detected by the second sheet detection sensor 705, does not unlock the storage case 210. Then, the control unit 203 causes the display unit 206 to notify the operator of the presence of a sheet jam, and prompts the operator to remove the jammed sheet.

[0074] In addition, when the pull-out button 205 is pressed, the control unit 203 checks the detection status of the second sheet detection sensor 705, and if a sheet is detected by the second sheet detection sensor 705, it may discharge the sheet into the double-fed sheet storage unit (escape tray) 218 ​​and unlock the storage cabinet 210 after the sheet is discharged.

[0075] Furthermore, when the pull-out button 205 of the storage 210 is pressed, if a sheet is being fed from another storage 210 and a sheet is detected by the second sheet detection sensor 705, the control unit 203 may suspend the instruction by the pull-out button 205. Then, the feeding operation may be continued, and the above-mentioned operation may be performed after the feeding operation from the other storage 210 is completed. That is, after the feeding operation is completed, a notification of the presence of a sheet jam may be performed, or the sheet may be discharged to the multiple-feed sheet storage unit 218, and the lock of the storage 210 may be released after the discharge. In this case, the control unit 203 may ignore the operation of the pull-out button 205 itself, and perform the above-mentioned operation when the pull-out button 205 is operated again after the feeding operation is completed.

[0076] [Prevention of jamming due to sagging sheets] As described above, if the hanging sheet S1 is transported further downstream by the downward movement of the pickup roller 231, the following problem may occur. That is, downstream of the first transport roller 232, there is a transport roller pair (registration roller pair) 237 consisting of a second transport roller 235 and an opposing roller 236. If the driving of the second transport roller 235 is stopped when the pickup roller 231 is descending, the hanging sheet S1 transported by the first transport roller 232 as the pickup roller 231 is descending may hit the transport roller pair 237.

[0077] Particularly in the case of this embodiment, the sheet feeding unit 230 is configured to be pulled out from the housing 204 together with the storage case 210, and the pickup roller 231 is moved to an upper position when the storage case 210 is pulled out in order to facilitate stacking of sheets on the stacking tray 221. Therefore, when the storage case 210 is attached to the housing 204, the movement amount of the pickup roller 231 when it moves from the upper position to the lower position is large, and the conveyance amount of the hanging sheet S1 accompanying the downward movement of the pickup roller 231 is also large.

[0078] If the hanging sheet S1 hits the pair of conveying rollers 237, the leading edge of the sheet may be crushed or damaged. If such a sheet is fed as is, a jam is likely to occur somewhere along the conveying path, and if a jam occurs, work such as removing the sheet is required. Therefore, in this embodiment, when the pickup roller 231 descends, the second conveying roller 235 is driven so that the hanging sheet S1 is conveyed downstream without hitting the pair of conveying rollers 237, as shown in FIG. 8(c).

[0079] That is, the second conveying roller 235 rotates so as to convey the sheet conveyed by the first conveying roller 232 further downstream in the conveying direction while the pickup roller 231 is descending. In this embodiment, the control unit 203 drives the conveying motor 235a that drives the second conveying roller 235 even while the pickup roller 231 is descending. The timing for starting rotation of the second conveying roller 235 may be any time before the hanging sheet S1 reaches the conveying roller pair 237, but since the position of the leading edge of the hanging sheet S1 at that time may not be fixed, it is preferable to start rotation of the second conveying roller 235 at the same time as the pickup roller 231 starts descending.

[0080] Alternatively, the second conveyor roller 235 may be driven based on the detection of a sheet by the second sheet detection sensor 705 located between the first conveyor roller 232 and the second conveyor roller 235. Specifically, if a sheet has already been detected by the second sheet detection sensor 705 when the pickup roller 231 starts to descend, the second conveyor roller 235 starts to rotate at the same time as the pickup roller 231 starts to descend. Also, if a sheet has not been detected by the second sheet detection sensor 705 when the pickup roller 231 starts to descend, and a sheet is detected by the second sheet detection sensor 705 during the descent of the pickup roller 231, the second conveyor roller 235 starts to rotate at this time.

[0081] The conveying roller pair 237 arranged downstream of the separation conveying roller pair 234 also serves as a registration roller that abuts the sheet conveyed by the separation conveying roller pair 234 while the driving is stopped, and forms a loop in the sheet, thereby correcting the skew of the sheet. In the case of this embodiment, when the hanging sheet S1 is being conveyed while the pickup roller 231 is descending as described above, the conveying roller pair 234 does not abut the sheet, but the sheet may be abutted.

[0082] That is, as shown in FIG. 9, the hanging sheet S1 conveyed while the pickup roller 231 is descending is abutted against the pair of conveying rollers 234 whose driving is stopped, forming a loop. At this time, the downward movement of the pickup roller 231 is stopped midway to correct the skew of the sheet. Thereafter, the downward movement of the pickup roller 231 is resumed, and the second conveying roller 235 is started to be driven to convey the hanging sheet S1. The timing at which the hanging sheet S1 abuts against the pair of conveying rollers 234 is grasped by detecting the leading edge of the hanging sheet S1 by the second sheet detection sensor 705. The downward movement of the pickup roller 231 is stopped at a predetermined timing from the sheet detection by the second sheet detection sensor 705, at which a loop is formed in the hanging sheet S1. Then, after correcting the skew of the hanging sheet S1, the downward movement of the pickup roller 231 is resumed as described above, and the second conveying roller 235 is started to rotate. Specifically, the second conveying rollers 235 start to rotate based on the fact that the first conveying rollers 232 have conveyed the sheet by a predetermined amount from the time when the second sheet detection sensor 705 detects the sheet.

[0083] It is preferable that the above-mentioned skew correction of the hanging sheet S1 is performed when the second sheet detection sensor 705 does not detect a sheet when the storage 210 is attached and the pickup roller 231 starts to descend. For example, if the first sheet detection sensor 704 detects a sheet when the pickup roller 231 starts to descend but the second sheet detection sensor 705 does not detect a sheet, the pickup roller 231 starts to descend with the driving of the second conveying roller 235 stopped, the hanging sheet S1 is abutted against the pickup roller 231, a loop is formed, and the descent of the pickup roller 231 is stopped. Then, after the skew correction is performed, the driving of the second conveying roller 235 is started and the descent of the pickup roller 231 is resumed.

[0084] On the other hand, if a sheet is detected by the second sheet detection sensor 705 when the storage case 210 is attached and the pickup roller 231 begins to descend, no skew correction of the drooping sheet S1 is performed, and the second conveying roller 235 begins to be driven at the timing when the pickup roller 231 begins to descend or when the second sheet detection sensor 705 detects a sheet, as described above.

[0085] In such a case, the drooping sheet S1 hits the pair of conveying rollers 237 while the pickup roller 231 is descending, and the second conveying roller 235 is driven when the pickup roller 231 resumes its downward movement. That is, in this case as well, the second conveying roller 235 starts to be driven while the pickup roller 231 is descending. Note that, when skew correction is not performed by the pair of conveying rollers 237, the sheet is conveyed to the image forming apparatus 100 after skew correction is performed on a conveying path downstream of the pair of conveying rollers 237 of the multi-tier storage device 200.

[0086] In this way, by driving the second conveying roller 235 when the pickup roller 231 descends, it is possible to wait for an instruction to start feeding the sheet without damaging the leading edge of the hanging sheet S1, and the sheet can be treated as a valid sheet as described above.

[0087] [Position management of sagging sheets] Here, the hanging sheet S1 is treated as a valid sheet in this way, but the position of the leading edge of the hanging sheet S1 is not determined when the pickup roller 231 starts to descend. For this reason, unless the amount of conveyance of the sheet by the second conveyance roller 235 is managed, it is difficult to treat the hanging sheet S1 as a valid sheet.

[0088] Therefore, in this embodiment, the second conveying roller 235 rotates a certain amount and then stops from the point when the second sheet detection sensor 705 detects the sheet. In other words, the control unit 203 controls the drive amount of the second conveying roller 235 based on the detection result of the second sheet detection sensor 705 so that the leading edge of the hanging sheet S1 is positioned at a predetermined position.

[0089] The predetermined position where the leading end of the hanging sheet S1 is stopped is preferably a position where the hanging sheet S1 can be easily cleared if the hanging sheet S1 is treated as a jammed sheet (jammed sheet). For example, when the pull-out button 205 is operated in a state where the hanging sheet S1 is present as described above, the hanging sheet S1 may be treated as a jammed sheet. Also, when the door provided for jamming clearance of the multi-tiered storage device 200 is opened, the hanging sheet S1 may be touched by an operator, and it may be determined that the position cannot be managed, and the hanging sheet S1 may be treated as a jammed sheet. Therefore, in this embodiment, the predetermined position is set to a position where the leading end of the hanging sheet S1 is located a predetermined distance downstream from the downstream end of the nip portion of the conveying roller pair 237 composed of the second conveying roller 235 and the opposing roller 236, and where the hanging sheet S1 can be easily picked up by an operator who opens the door and accesses the device.

[0090] However, if the leading edge position of the hanging sheet S1 protrudes too far from the second conveying roller 235, there is a risk of interference with sheets fed from other storage cabinets 210, so the specified position is a position where the leading edge position of the hanging sheet S1 stops upstream of the position where it joins the conveying path of the sheets fed from other storage cabinets 210.

[0091] In addition, when there is a hanging sheet and a sheet jams due to feeding from another storage 210, the control unit 203 may allow the hanging sheet to be used as a valid sheet without notifying the jam. This is because when a jammed sheet fed from another storage 210 is cleared, there is a risk that the hanging sheet will be removed and cannot be used effectively. After the feeding of the hanging sheet is completed, a notification of a jam of a sheet fed from another storage 210 may be issued.

[0092] [Handling of sagging sheets when the empty sensor detects them] As described above, in this embodiment, the hanging sheet S1 is treated as a valid sheet, but even if the hanging sheet S1 is present, if the empty sensor 702 does not detect this sheet, it may be determined that there is no sheet in the storage 210. For example, if the hanging sheet S1 is a small-sized sheet with a short length in the conveying direction, even if the hanging sheet S1 is sandwiched between the separation conveying roller pair 234, the sheet may not be detected by the empty sensor 702, and the control unit 203 may determine that the storage 210 is empty.

[0093] Therefore, in this embodiment, even if no sheet is detected by empty sensor 702, when second sheet detection sensor 705 detects a sheet due to the downward movement of pickup roller 231, control unit 203 determines that there is a sheet that can be fed by pickup roller 231. In other words, when hanging sheet S1 is detected by second sheet detection sensor 705, control unit 203 does not determine that storage case 210 is empty even if hanging sheet S1 is not detected by empty sensor 702.

[0094] Here, the operation when feeding sheets on stacking tray 221 will be described with reference to Figures 10(a) and (b). First, with storage 210 attached to the attachment position of housing 204 and pickup roller 231 positioned at the lower position, stacking tray 221 is raised by lifting mechanism 226 (Figure 5) as shown in Figure 10(a). Then, when the top sheet on stacking tray 221 abuts against pickup roller 231 and is detected by upper surface detection sensor 700 (Figures 5 and 7), sheet feeding starts as shown in Figure 10(b).

[0095] On the other hand, when the empty sensor 702 does not detect a sheet even if the stacking tray 221 is raised, the control unit 203 normally determines that there is no sheet on the stacking tray 221, and causes the display unit 206 to notify that there is no sheet in the storage case 210. Of course, sheet feeding is not started either.

[0096] Here, the detailed configuration of the empty sensor 702 of this embodiment will be described with reference to Figures 11(a) and (b). The empty sensor 702 has an arm 702b as a swinging member supported so as to be rotatable about a swing shaft 702a, and a photointerrupter 702c as a detection means for detecting the position of the arm 702b. A flag 702d is integrally provided on the arm 702b, and the flag 702d is configured to be able to pass through the photointerrupter 702c by the swing of the arm 702b.

[0097] On the other hand, a recess 221b is formed in the loading surface 221a on which the sheets of the loading tray 221 are loaded, and as shown in Fig. 11(a), when the tip of the arm 702b is located in the recess 221b, the flag 702d is configured to be disengaged from the photointerrupter 702c. As shown in Fig. 11(b), when the tip of the arm 702b is in contact with a sheet on the loading tray 221, the flag 702d is located between the light emitting portion and the light receiving portion of the photointerrupter 702c, and the control unit 203 determines that a sheet is present on the loading tray 221 from the signal of the photointerrupter 702c.

[0098] 11(a), if the hanging sheet is a small-sized sheet S2 and the rear end of the sheet S2 is located downstream of the tip of the arm 702b of the empty sensor 702, the tip of the arm 702b will enter the recess 221b of the stacking tray 221. As a result, even though there is a hanging sheet, the empty sensor 702 will not detect this sheet S2. For this reason, in this embodiment, when the sheet S2 is detected by the second sheet detection sensor 705, it is determined that there is a sheet in the storage 210 regardless of the detection result of the empty sensor 702, and this sheet S2 can be fed.

[0099] In this embodiment, the stacking tray 221 is raised as described above to position the top sheet on the stacking tray 221 at a position where it can be fed. Therefore, even if the empty sensor 702 does not detect a sheet when the lifting mechanism 226 raises the stacking tray 221 to a position where the sheet on the stacking tray 221 can be fed by the pickup roller 231, the control unit 203 determines that there is a sheet that can be fed from the stacking tray 221 if the second sheet detection sensor 705 detects a sheet due to the lowering operation of the pickup roller 231.

[0100] Furthermore, when no sheet is detected by the empty sensor 702 and the second sheet detection sensor 705 detects a sheet due to the lowering operation of the pickup roller 231, the control unit 203 causes the lifting mechanism 226 to lower the stacking tray 221 to a predetermined stacking position (intermediate position). That is, in such a case, after the hanging sheet is fed, the display unit 206 notifies the user that there are no sheets in the storage case 210, but by moving the stacking tray 221 to the predetermined stacking position, the stacking tray 221 can be positioned at a position where sheets can be easily stacked when the operator pulls out the storage case 210 to replenish sheets.

[0101] Note that even if the empty sensor 702 has not detected a sheet, if the second sheet detection sensor 705 has detected a sheet due to the downward movement of the pickup roller 231, the control unit 203 does not cause the display unit 206 to notify that there is no sheet on the stacking tray 221. In other words, if there is a hanging sheet, even if the empty sensor 702 has not detected this sheet, the control unit 203 does not cause the display unit 206 to display that the storage 210 is empty.

[0102] Furthermore, as described above, when there is a hanging sheet that is not detected by empty sensor 702, even if the power of the device is turned off, control unit 203 stores that fact and maintains this state even when the power is turned on the next time. In other words, when there is a hanging sheet that is not detected by empty sensor 702, regardless of whether the power of the device is turned on or off, display unit 206 does not display that storage 210 is empty. This allows control unit 203 to know the presence of a hanging sheet even when the power is turned on the next time, and this sheet can be used effectively.

[0103] [Job start control] Next, a specific example of the control of this embodiment as described above will be described. First, with reference to FIG. 12, the control when the multi-tiered storage device 200 receives an instruction to start feeding sheets and starts a sheet feeding operation (job) will be described. First, when the control unit 203 receives an instruction to start feeding sheets, it checks whether there are any sheets remaining on any of the conveyance paths of the multi-tiered storage device 200 (S1). As described above, the remaining sheets are checked by the sheet detection sensors arranged on each conveyance path. If there are no remaining sheets on any of the conveyance paths (Y in S1), the control unit 203 permits the job and starts feeding sheets (S2).

[0104] On the other hand, if there is a remaining sheet on any of the conveying paths (N in S1), the control unit 203 checks whether the sheet is a drooping sheet (S3). If the remaining sheet is not a drooping sheet (N in S3), the control unit 203 prohibits the job, does not start feeding the sheet, and notifies the display unit 206 that a jam has occurred (S4). If the remaining sheet is a drooping sheet in S3 (Y in S3), the process proceeds to S2, where the job is permitted and feeding of the drooping sheet is started.

[0105] [Control when the storage unit is pulled out] Next, the control when the storage 210 is pulled out (control when the storage is opened) will be described with reference to Fig. 13. When the pull-out button 205 is pressed (S101), the control unit 203 checks whether or not there is a hanging sheet (S102). If there is a hanging sheet (N in S102), the lock on the storage 210 is not released and a notice that a jam has occurred is displayed on the display unit 206 (S103).

[0106] On the other hand, when there is no hanging sheet (Y in S102), the control unit 203 raises the pickup roller 231 from the lower position to the upper position (S104). At the same time, the stacking tray 221 starts to lower toward the predetermined stacking position (S105). Then, the control unit 203 waits for the pickup roller 231 to finish rising to the upper position (S106), and when the lifting to the upper position is completed (Y in S106), the control unit 203 releases the lock of the storage 210 (S107). That is, the control unit 203 turns on the drawing solenoid 205a (see FIG. 7) to release the lock mechanism that has locked the storage 210 at the mounting position. As a result, the storage 210 is pushed from the mounting position of the housing 204 toward the drawing position by a spring (not shown). When a certain time has elapsed since the drawing solenoid 205a was turned on (Y in S108), the control unit 203 turns off the drawing solenoid 205a (S109).

[0107] The downward movement of the stacking tray 221 continues even while the storage case 210 is being pulled out, and when the stacking tray 221 reaches a predetermined stacking position (intermediate position) (S110), the downward movement of the stacking tray 221 stops (S111). As a result, the pickup roller 231 is in the upper position, and the storage case 210 is in the pulled-out position with the stacking tray 221 in the intermediate position, making it easy for the operator to replenish sheets.

[0108] [Control when installing storage unit] Next, the control when the storage 210 is attached (control when the storage is closed) will be described with reference to Fig. 14. When the storage 210 is attached to the attachment position, the control unit 203 can confirm this from the detection result of the attachment sensor 703 (Fig. 7) (S201). Next, the control unit 203 starts to lower the pickup roller 231 from the upper position to the lower position (S202). At this time, the drive of the second conveyor roller 235 also starts (S203). This is to ensure that, if there is a drooping sheet as described above, this sheet is conveyed without hitting the second conveyor roller 235.

[0109] Here, the completion of the movement of pickup roller 231 to the lower position is determined based on the elapsed time from the start of movement from the upper position. That is, when a predetermined time has elapsed since the start of movement from the upper position, it is determined that pickup roller 231 has completed the movement from the upper position to the lower position. Therefore, control unit 203 counts the time from the start of the descent of pickup roller 231, and checks whether the predetermined time has elapsed (S204).

[0110] When a predetermined time has elapsed since the pickup roller 231 started to descend (Y in S204), the control unit 203 stops driving the feed motor 301 that drives the pickup roller 231 (S205), and also stops driving the conveying motor 235a that drives the second conveying roller 235 (S206). This causes the pickup roller 231, the first conveying roller 232, and the second conveying roller 235 to stop rotating.

[0111] Next, the control unit 203 starts lifting the stacking tray 221 (S207) and checks whether the top surface detection sensor 700 (FIGS. 5 and 7) is ON (S208). When the top surface detection sensor 700 is ON, the control unit 203 stops lifting the stacking tray 221 (S209). If there are sheets on the stacking tray 221, the top surface detection sensor 700 detects the top sheet. On the other hand, if there are no sheets on the stacking tray 221, the control unit 203 detects the stacking surface of the stacking tray 221.

[0112] At this time, the control unit 203 checks whether or not there is a sheet on the stacking tray 221 by the empty sensor 702 (S210). If the empty sensor 702 detects the presence of a sheet (Y in S210), the sheet can be fed by the pickup roller 231, so the control unit 203 ends the control and waits for an instruction to start feeding the sheet.

[0113] Meanwhile, in S204, the control unit 203 checks whether the second sheet detection sensor 705 detects a sheet (S211) before a predetermined time has elapsed since the pickup roller 231 started to move (N in S204). Here, the presence or absence of a hanging sheet is checked during the downward movement of the pickup roller 231. If the second sheet detection sensor 705 detects a sheet in S211 (Y in S211), that is, if there is a hanging sheet, the sheet is conveyed a certain amount from when the second sheet detection sensor 705 detects the sheet (S212). In practice, the driving time of the rollers is managed so that the sheet is conveyed a certain amount. That is, when a certain time has elapsed since the second sheet detection sensor 705 detected the sheet, the driving of the first conveying roller 232 and the second conveying roller 235 is stopped.

[0114] The reason for conveying the sheet by a fixed amount in this manner is, as described above, to keep the leading end position of the hanging sheet at a predetermined position so that when the sheet needs to be removed, the sheet can be easily picked up and the position does not interfere with sheets fed from other storages 210. The control unit 203 also stores the fact that the hanging sheet is in a standby state (S213). Then, the process proceeds to S205.

[0115] Furthermore, in S210, if the empty sensor 702 does not detect a sheet (N in S210), it is confirmed whether the hanging sheet was in a standby state in the above-mentioned S213 (S214). If the hanging sheet is in a standby state (Y in S214), the controller 203 can feed the hanging sheet, so it ends the control and waits for an instruction to start feeding the sheet.

[0116] On the other hand, if there is no hanging sheet in S213 (N in S214), the control unit 203 notifies the display unit 206 that there is no sheet in the storage 210 (S215). Then, the control unit 203 starts lowering the stacking tray 221 to a predetermined stacking position (S216). The control unit 203 checks whether the stacking tray 221 has reached the predetermined stacking position (S217), and if it has reached the predetermined stacking position (Y in S216), stops the lowering of the stacking tray 221 (S218). Whether the stacking tray 221 has reached the predetermined stacking position (intermediate position) is determined by detecting that the stacking tray 221 has reached the predetermined stacking position using a sensor (not shown). Note that, in consideration of a case where this sensor is broken, the lowering of the stacking tray 221 is also stopped when the lower limit detection sensor 701 detects the stacking tray 221. When the lowering of the stacking tray 221 stops, the control unit 203 ends the control.

[0117] In the case of this embodiment, when a drooping sheet is present as described above, the sheet feeding operation is not stopped and the drooping sheet is treated as a valid sheet. In other words, by not treating the drooping sheet as a jammed sheet, the frequency of jamming can be reduced and a decrease in productivity can be suppressed.

[0118] In addition, by treating the hanging sheet as a valid sheet in this way, it is possible to reduce the waste of sheets. In particular, even if the hanging sheet is a small size sheet and is not detected by the empty sensor 702, if the second sheet detection sensor 705 detects the sheet, it is determined that the sheet is present in the storage 210, and the sheet can be fed.

[0119] Moreover, the above-mentioned drooping sheet is conveyed by the downward movement of the pickup roller 231. In the case of this embodiment, the upper position of the pickup roller 231 is a position that is largely retreated from the lower position so that the sheets can be easily stacked on the stacking tray 221. Therefore, the pickup roller 231 moves a large amount from the upper position to the lower position, and the drooping sheet is also conveyed accordingly. However, in this embodiment, the second conveying roller 235 located downstream of the separation conveying roller pair 234 is driven while the pickup roller 231 is descending. Therefore, the sheet conveyed while the pickup roller 231 is descending is conveyed without hitting the second conveying roller 235, and the occurrence of sheet jamming can be suppressed.

[0120] <Other embodiments> In the above embodiment, the sheet feeding device is the multi-tier storage device 200, but the sheet feeding device of the present invention is not limited to this, and may be one equipped with one storage. For example, it may be the feeding deck 500 shown in FIG. 1, or the sheet feeding device 120 equipped in the image forming apparatus 100.

[0121] In the above embodiment, the control unit 203 for controlling the feeding motor 301 and the like is provided in the multi-tier storage device 200, but these controls may be performed by the control unit 140 of the image forming apparatus 100. The sheet feeding device may be of another configuration, such as a single deck, regardless of the above-mentioned multi-tier storage device. [Explanation of symbols]

[0122] 200... multi-tier storage device (sheet feeding device) / 203... control section (determination means) / 204... housing (device main body) / 205... pull-out button (operation means) / 206... display section (notification means) / 210... storage / 221... stacking tray / 226... lifting mechanism (lifting means) / 230... sheet feeding section (feeding section) / 231... pickup roller (feeding roller) / 232... first conveying roller (conveying roller) / 235... second conveying roller / 300... drive transmission mechanism (driving means) / 301... feed motor (driving motor) / 702... empty sensor (first detection means) / 705... second sheet detection sensor (detection means, second detection means)

Claims

1. A storage unit that is movable between a drawn-out position where it is drawn out relative to a device body and an attached position where it is attached to the device body; a loading tray provided in the storage case and on which sheets are loaded; a feeding roller for feeding the sheets stacked on the stacking tray; a first conveying roller for conveying the sheet fed by the feeding roller; a second conveying roller provided downstream of the first conveying roller in a sheet conveying direction; a driving means for raising the feed roller before the storage case moves to the pull-out position and lowering the feed roller after the storage case moves to the mounting position, the first conveying roller is rotated by the driving means in a direction to convey the sheet while the feed roller is lowered, The second transport roller rotates to transport the sheet transported by the first transport roller downstream in a transport direction while the feed roller is moving downward.

2. 2. The sheet feeding device according to claim 1, wherein the driving means includes a drive motor that rotates in one direction to lower the feeding roller and rotates the first transport roller in the transport direction.

3. 3. The sheet feeding device according to claim 1, wherein the second transport roller starts rotating at the same time that the driving means starts to lower the feeding roller.

4. a detection unit for detecting a sheet between the first conveying roller and the second conveying roller, 4. The sheet feeding device according to claim 1, wherein the second transport roller rotates a certain amount from the time when the detection means detects the sheet, and then stops.

5. a detection unit for detecting a sheet between the first conveying roller and the second conveying roller, 3. The sheet feeding device according to claim 1, wherein the second transport roller starts rotating when the detection means detects the sheet.

6. 6. The sheet feeding device according to claim 5, wherein the second transport roller rotates a certain amount from the time when the detection means detects the sheet and then stops.

7. A sheet feeding device as described in any one of claims 1 to 6, characterized in that the driving means raises the feeding roller to an upper position for placing a sheet on the loading tray before the storage cabinet is pulled out from the mounting position and reaches the pulled-out position, and lowers the feeding roller to a lower position for abutting the sheet on the loading tray after the storage cabinet moves to the mounting position.

8. a feeding section including the feeding roller and the first conveying roller, 8. The sheet feeding apparatus according to claim 7, wherein the feeding section is configured to be able to be pulled out and attached to the apparatus body simultaneously with the storage case.

9. a detection unit for detecting a sheet between the first conveying roller and the second conveying roller, 3. The sheet feeding device according to claim 1, wherein the second transport roller starts to rotate based on the fact that the first transport roller has transported a predetermined amount of the sheet from the time when the detection means detects the sheet.

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