JP7601608B2 - Sheet Feeding Device - Google Patents

Description

The present invention relates to a sheet feeding device that feeds sheets.

A sheet feeding device that feeds sheets uses a pickup roller to feed sheets from a stacking tray, and transports them using a transport roller. One such sheet feeding device has 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 is known in which the pickup roller is raised and lowered using a drive motor that drives the pickup roller and transport roller (for example, Patent Document 1).

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 transport roller by the action of a one-way clutch. The forward rotation of the drive motor rotates the pickup roller and the transport roller in the direction to transport the sheet and lowers the pickup roller, and the reverse rotation raises the pickup roller.

JP 2005-303610 A

In the configuration described in Patent Document 1 above, in which the conveying roller is driven in the direction of conveying 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.

Downstream of the conveying rollers is a sheet detection sensor that detects the presence or absence of a sheet. Normally, if this sheet detection sensor detects a jammed sheet, sheet feeding is stopped. The user must then remove the jammed sheet. As mentioned above, a sheet conveyed by the conveying rollers when the pickup roller is lowered may stop in a state where it is detected by the sheet detection sensor, but this sheet is not jammed and can be used for image formation. Therefore, if such a sheet is treated as a jammed sheet, sheet feeding cannot be resumed unless the sheet is removed, resulting in reduced productivity.

The present invention aims to provide a configuration that can suppress a decrease in the productivity of the device.

The sheet feeding device of the present invention comprises a feeding section having a loading tray on which sheets are loaded, a feeding roller for feeding the sheets loaded on the loading tray, and a transport roller for transporting the sheets fed by the feeding roller, a driving means for raising and lowering the feeding roller, a detection means for detecting a sheet downstream of the transport roller in the sheet transport direction, and a judgment means for judging the presence or absence of a sheet jam based on the detection state of the detection means, and is characterized in that the judgment means judges that there is no jam for a sheet detected by the detection means while the feeding roller is moving downward.

The present invention can prevent a decrease in the productivity of the device.

1 is a cross-sectional view showing a schematic configuration of an image forming system according to an embodiment. FIG. 2 is a front view of the multi-tier storage device according to the embodiment. FIG. 2 is a plan view showing the multi-tier storage device according to the embodiment with the storage compartments pulled out. FIG. 2 is a side view showing the multi-tier storage device according to the embodiment with the storage compartments pulled out. FIG. 1 is a schematic diagram of a storage unit according to an embodiment. FIG. 4 is a diagram showing a driving configuration of a sheet feeding unit according to the embodiment. FIG. 4 is a block diagram of a control configuration of the multi-tier storage device according to the embodiment. 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. 6A to 6C are diagrams illustrating an example of performing skew correction of a sheet while a pickup roller 231 is descending according to the embodiment. 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. 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. 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. 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. 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.

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

[Image forming system]
1 is a cross-sectional view showing an example of an image forming system including a multi-tiered storage device and an image forming apparatus according to the present embodiment. In the following description, an electrophotographic laser printer system (hereinafter simply referred to as a printer) will be described as an example of an image forming apparatus having an image forming unit. 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 in a different manner, such as an inkjet type, regardless of the electrophotographic type.

The image forming system 1000 of this embodiment includes an image forming apparatus 100, a multi-tier storage device 200 as a sheet feeding device connected to the image forming apparatus 100, and a feed deck 500. As described later in detail, the multi-tier storage device 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-tier storage device 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-tier storage device 200. Examples of 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 simply be referred to as the "downstream side", and the upstream side of the sheet conveying direction may simply be referred to as the "upstream side".

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 communicatively connected to the image forming apparatus main body 101. In this embodiment, the document reading device 102 is disposed above the image forming apparatus main body 101.

When reading an original, the original reading device 102 irradiates the original placed on the platen glass 103 with light from a scanning optical system light source, and the reflected light is input to a CCD to read the original image. The original reading device 102 also has an automatic document feeder (ADF) 104, and the original placed on a tray 105 can be automatically transported by the ADF 104 to the 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 the image forming section 110, which will be described later. Note that the laser scanner 113 may also receive image data sent from a personal computer, etc., as described above.

The image forming apparatus 100 includes an image forming section 110, a plurality of sheet feeding devices 120, a sheet conveying device 130, and the like. Each section of the image forming apparatus 100 is controlled by a control section 140. The control section 140 has a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU controls each section while reading out 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 aforementioned programs, etc.

Each of the multiple sheet feeding devices 120 includes a cassette 121 that stores sheets S, a pickup roller 122, and a separation and 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 and conveying roller pair 125, which move up and down and rotate at a predetermined timing.

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 the sheet conveying path 134 by the conveying roller pair 131 and then guided to the registration roller pair 133. The sheet S is then fed into the image forming unit 110 at a predetermined timing by the registration roller pair 133.

Note that sheets transported from the multi-tier storage device 200 or the feed deck 500 described below via the transport roller pair 201 are transported into the image forming device 100 via a connection path 202 with the image forming device 100. The sheets transported from the multi-tier storage device 200 or the feed deck 500 into the image forming device 100 are sent to the image forming unit 110 at a predetermined timing via the registration roller pair 133, similar to the sheets transported from the sheet feeder 120 in the image forming device 100.

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 rotated, 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 the laser scanner 113, which is emitted in response to an image signal, to form 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.

The toner image on the photosensitive drum 111 is then transferred to the sheet S by the transfer device 115 in the transfer section 116. The sheet S onto which the toner image has been transferred is then transported to the fixing device 150 where the toner image is fixed, and is then discharged by the discharge rollers 151 onto the discharge tray 152 outside the machine.

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

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

[Multi-tier storage device]
An overview of the multi-tier storage device 200 will be described with reference to Figures 1 to 5. The multi-tier storage device 200 includes a plurality of storage cabinets 210, an intermediary transport device 400, and the like. 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.

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

Furthermore, a multi-feed detection sensor that detects multi-feeding of sheets is disposed on the transport path 212 after merging with the transport path 213, the relay transport device 400, and the transport path 214. A sheet for which a multi-feed is detected by the multi-feed detection sensor is transported to the transport path 217. A multi-feed sheet storage section (escape tray) 218 that stores sheets for which a multi-feed is detected is disposed below the transport path 217. A sheet for which a multi-feed is detected and transported to the transport path 217 is transported to the multi-feed sheet storage section by switching the transport path by a switching member 219 provided on the transport path 217.

Figure 2 is a front view of the multi-tier storage device 200. As described above, the multi-tier 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 multi-tier storage device 200. Note that 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 number of sheets that can be stored in each storage cabinet 210 is the same.

The sheets fed from each storage unit 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 CPU (Central Processing Unit) 203a, a ROM (Read Only Memory) 203b, and a RAM (Random Access Memory) 203c. In addition, the control unit 203 can communicate with the control unit 140 of the image forming device 100, and controls the timing of sheet feeding by communicating with the control unit 140.

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 of each storage 210. For example, when an operator presses the pull-out button 205, the pull-out solenoid 205a (see FIG. 7) operates, the 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 FIG. 3 and FIG. 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.

As shown in Figs. 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 device 100. As shown in Fig. 4, the sheet storage section 220 has a stacking tray 221 on which sheets S are stacked, 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.

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 loading tray 221 and the drive pulley 228a via the guide pulley 228b. The loading tray 221 is supported so that it can move up and down along the rail 229. The drive pulley 228a is driven to rotate by the lifting motor 227, thereby winding or pulling out the wire 228c, and the movement of the wire 228c is transmitted to the loading tray 221 via the guide pulley 228b. As a result, the loading tray 221 rises and falls along the rail 229.

In this embodiment, the stacking tray 221 descends to a predetermined stacking position when the sheets S are stacked, and gradually descends 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 gradually rises. The predetermined stacking position is also called the 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 sheets, it is difficult for users to load sheets onto the stacking tray 221. For this reason, when storing sheets, the descent of the stacking tray 221 is stopped at the intermediate position, and the stacking tray 221 is lowered each time a sheet is stacked.

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.

As shown in FIG. 4, the abutment portion 222 is disposed downstream in the sheet transport direction in the storage space 225 in which the sheets are stored, and is abutted by the downstream end (leading end) of the sheet in the transport direction stacked on the stacking tray 221. The rear end regulating plate 223 is disposed upstream in the sheet transport direction in the storage space 225, and is abutted by the upstream end (rear end) of the sheet in the transport direction stacked on the stacking tray 221, thereby regulating the rear end position of the sheet. The rear end regulating plate 223 is movable in the sheet transport direction, and the rear end regulating position of the sheet can be adjusted according to the sheet size. The side regulating plates 224 are disposed on both sides in the width direction perpendicular to the sheet transport 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 the regulating position in the width direction of the sheet can be adjusted according to the sheet size.

As shown in FIG. 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 consisting of a first conveying roller (conveying roller) 232 and a retard roller 233, and a conveying roller pair (registration roller pair) 237 consisting of a second conveying roller 235 and an opposing roller 236. As shown in FIG. 4, 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 approximately in the center in the width direction.

The pickup roller (feed roller) 231 is provided in the storage 210 and feeds (feeds) the sheets stored in the storage 210. Specifically, the pickup roller 231 is provided above the stacking tray 221 and feeds the top sheet of the sheets S stacked on the raised stacking tray 221 by contacting it. For this reason, as shown in FIG. 5, the pickup roller 231 is disposed near the leading edge of the sheet S in the sheet transport direction (arrow α direction) so that it can press the top sheet on the stacking tray 221 with an appropriate force. Then, the pickup roller 231 is rotated by the drive of the feed motor 301 as a drive source to feed the top sheet in the arrow α direction.

When two or more overlapping sheets are fed from the pickup roller 231, the separation conveying roller pair 234 separates them 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 the opposite direction to the first conveying roller 232, and pushes back the sheets other than the top sheet of the two or more sheets fed from the pickup roller 231 to the stacking tray 221 side. 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, it is rotated by the sheet conveyed by the first conveying roller 232.

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 driven to rotate by a conveying motor 235a. That is, the sheet in the topmost storage 210 in FIG. 1 is conveyed to conveying path 212, the sheet in the second storage 210 to conveying path 213, and the sheet in the bottommost storage 210 to 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.

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, it moves together with the storage case 210. In other words, the sheet feeding unit 230 is configured so that it can be pulled out and attached to the housing 204, which serves as the device body, at the same time as the storage case 210. In this way, by configuring the sheet feeding unit 230 so that it can be pulled out together with the storage case 210, maintenance such as replacement of the rollers of the sheet feeding unit 230 is made easy.

[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 being driven by the feeding motor 301.

The drive transmission mechanism (feed drive unit) 300 for the first conveyor roller 232 and the pick-up roller 231, and the drive transmission mechanism (conveyor drive unit) 600 for the second conveyor roller 235 will be described below with reference to FIG. 6. Note that FIG. 6 shows the drive transmission path from the feed motor 301 to the pick-up roller 231, and the drive transmission path from the conveyor motor 235a to the second conveyor roller 235.

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

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.

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 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.

The drive transmission mechanism 300 as a driving means has a feed motor 301 capable of rotating in both directions, which rotates in one direction (forward rotation) to lower the pickup roller 231 and rotate the first conveying roller 232 in the sheet conveying direction. The forward rotation drive of the feed motor 301 is transmitted from pulley P1 to pulley P2 via a timing belt T1. The drive of the pulley P2 is transmitted in the order of gear Z1, gear Z2, and gear Z3 attached to the drive shaft 232a of the first conveying roller 232 via a coupling 302, and the first conveying roller 232 rotates in the direction of conveying the sheet. A pulley P3 is provided on the drive shaft 232a of the first conveying roller 232, and the 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.

In addition, one end of lift arms 350a, 350b is attached to the drive shaft 232a of the first transport roller 232 as a support member that supports the pickup roller 231. Rotation of the drive shaft 232a in the transport direction (forward drive of the feed motor 301) rotates the lift arms 350a, 350b and lowers the pickup roller 231. When the pickup roller 231 contacts a sheet on the stack tray 221, the spring clutches CL1 and CL2 act to cause the drive shaft 232a of the first transport roller 232 to rotate freely relative to the lift arms 350a, 350b.

On the other hand, the reverse drive of the feed motor 301 is also transmitted to the drive shaft 232a of the first conveyor roller 232, which rotates the lifting arms 350a, 350b to raise the pickup roller 231. At this time, the first conveyor roller 232 does not rotate due to the action of the one-way clutch OW1 provided inside it. The raised lifting arms 350a, 350b come into contact with a regulating member (not shown), and the action of the spring clutch CL3 causes the lifting arms 350a, 350b to rotate freely relative to the drive shaft 232a of the first conveyor roller 232.

In this way, 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, which serves as a drive means, raises and lowers the pickup roller 231 to a lower position for contacting a sheet on the stack tray 221, and to an upper position above the lower position for placing a sheet on the stack tray 221.

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 top 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 raising the stacking tray 221 by the lifting mechanism 226 as described above, the top 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 freely relative to the drive shaft 232a, and the pickup roller 231 to maintain contact with the top surface of the sheets.

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, 350b rotate in the direction (upward) away from the sheets on the stacking tray 221 as the drive shaft 232a rotates in the reverse direction, lifting the pickup roller 231. Then, a part of the lifting arms 350a, 350b abuts against a regulating member (not shown), and the rotation stops. 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, CL2 act, and the lifting arms 350a, 350b rotate freely relative to the drive shaft 232a. The pickup roller 231 is then held in the upper position.

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

[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, transport motor 235a, and 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.

The display unit 206 is, for example, an LED, and when the storage 210 runs out of sheets or when a sheet jams along 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 the storage 210, and when the red LED is turned on, it may indicate that there is no sheet in the storage 210. In addition to or instead of such an LED, the display unit may be capable of displaying images such as an LCD screen, and the location of the display unit is not limited to the vicinity of the pull-out button 205, and may be provided in one location rather than for each storage 210.

The multi-tier storage device 200 also includes various sensors, such as an upper surface detection sensor 700, a lower limit detection sensor 701, an empty sensor 702, a mounting 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 topmost sheet stacked on the stacking tray 221 by contacting 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.

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. 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 descent of the stacking tray 221.

The empty sensor 702, which serves as the first detection means, detects sheets 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 sheets on the stacking tray 221. The empty sensor 702 detects the presence or absence of sheets at a position upstream of the pickup roller 231. When the control unit 203 determines that there are no sheets on the stacking tray 221 (on the stacking tray) (i.e., there are no sheets 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. The detailed configuration of the empty sensor 702 will be described later.

The mounting sensor 703 detects whether the storage 210 is mounted in 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.

The second sheet detection sensor 705, which serves as the detection means and the second detection means, is a sensor that detects a sheet between the first conveying roller 232 and the second conveying roller 235, and is located downstream of the first sheet detection sensor 704. When the second sheet detection sensor 705 detects a sheet, the control unit 203 determines that the sheet is present between the first conveying roller 232 and the second conveying roller 235. The sensors that detect the sheets are disposed at multiple locations on the conveying 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 the information from these sheet detection sensors, and display the location 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.

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

In this embodiment, as shown in FIG. 8(a), a flag 351 is provided on a part of the lift arm 350a (or 350b) that supports 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, it 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.

In the upper position, as shown in FIG. 8A, the pickup roller 231 moves to a position where a part of its outer circumference is directly above the first conveying 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.

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 pulled 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 pulled out, the pickup roller 231 is moved to the upper position where it is less likely to interfere with the loading of sheets.

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 with 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 in 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 pulled out from the mounting position and reaches the pulled 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 the pickup roller 231 from the upper position to the lower position is the amount by which an imaginary line passing through the center of rotation of the first conveyor roller 232 and the center of rotation of the pickup roller 231 rotates about the center of rotation of the first conveyor roller 232 by 60° or more, preferably 80° or more, and more preferably 90° or more.

[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.

If the storage case 210 is pulled out and installed as described above when there is a hanging sheet in this manner, the following problem may occur. That is, when the operator operates the pull-out button 205 to pull out the storage case 210 when there is a 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 conveying roller 232 that constitutes the separation conveying roller pair 234 does not rotate due to the one-way clutch OW1. As a result, the storage case 210 is pulled out with a hanging sheet in it.

Next, when the operator mounts the storage 210 in the mounting position with the hanging sheet still present, 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 of conveying the sheet. Therefore, as shown in FIG. 8(a), the hanging sheet S1 held between the separation conveying roller pair 234 is conveyed further downstream as shown in FIG. 8(b) by the downward movement of the pickup roller 231.

[Effective use of hanging sheets]
As described above, the second sheet detection sensor 705 is located 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. When the control unit 203 determines that a sheet has jammed, it causes the display unit 206 to notify that effect, as described above.

Here, as described above, the hanging sheet S1 conveyed by the first conveying roller 232 in conjunction 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, if such a valid sheet is detected by the second sheet detection sensor 705 and 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.

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 above-mentioned hanging sheet S1 is detected by the second sheet detection sensor 705, the display unit 206 is not notified that a jam exists.

The control unit 203 also determines whether a sheet is jammed and whether the sheet feeding operation can be performed, depending on 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 determines that a jam exists, the feeding operation is disabled, and if the control unit 203 determines that no jam exists, 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 determines that a sheet jam has occurred at that location, displays that fact on the display unit 206, and stops the sheet feeding operation.

However, the control unit 203 monitors the detection status of the second sheet detection sensor 705 when the pickup roller 231 is lowered. If the second sheet detection sensor 705 detects a sheet when the pickup roller 231 is lowered, the control unit 203 does not treat the sheet as a jammed sheet even if the sheet is detected by the second sheet detection sensor 705 at the time when the control unit 203 receives an instruction to start feeding. This reduces the frequency of jams, suppresses a decrease in productivity, and allows for effective use of sheets.

On the other hand, as described above, the hanging sheet S1 transported by the downward movement of the pickup roller 231 may stop in a state straddling the storage case 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 case 210, 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 case 210 to be pulled out if the second sheet detection sensor 705 detects a sheet when the pull-out button 205 is operated.

Specifically, 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, does not unlock the storage case 210. Then, the control unit 203 notifies the display unit 206 that a sheet is jammed, and prompts the operator to remove the jammed sheet.

The control unit 203 may check the detection status of the second sheet detection sensor 705 when the pull-out button 205 is pressed, and if a sheet is detected by the second sheet detection sensor 705, may discharge the sheet into the multi-feed sheet storage unit (escape tray) 218 and unlock the storage case 210 after the sheet is discharged.

In addition, 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 from 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 a sheet jam may be issued, or the sheet may be discharged to the multi-feed sheet storage unit 218 and the lock of the storage 210 may be released after the discharge. In such a 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.

[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.

In particular, 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 in order to facilitate stacking of sheets on the stacking tray 221, the pickup roller 231 is moved to an upper position when the storage case 210 is pulled out. Therefore, when the storage case 210 is attached to the housing 204, the amount of movement of the pickup roller 231 when it moves from the upper position to the lower position is large, and the amount of conveyance of the drooping sheet S1 accompanying the downward movement of the pickup roller 231 is also large.

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

That is, the second conveying roller 235 rotates 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 rotating the second conveying roller 235 at the same time as the pickup roller 231 starts descending.

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 rotating 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 rotating at this time.

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, as described above, when the hanging sheet S1 is being conveyed while the pickup roller 231 is descending, the conveying roller pair 234 does not abut the sheet, but it may be configured to abut the sheet.

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 to form a loop. At this time, the downward movement of the pickup roller 231 is stopped midway to correct the skew of the sheet. After that, 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 starts to rotate. Specifically, the second conveyor roller 235 starts to rotate based on the fact that the first conveyor roller 232 has conveyed a predetermined amount of the sheet from the point when the second sheet detection sensor 705 detects the sheet.

The skew correction of the hanging sheet S1 as described above is preferably performed when the second sheet detection sensor 705 does not detect a sheet when the storage 210 is installed 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 second conveyor roller 235 stopped, and the hanging sheet S1 is abutted and a loop is formed, and the descent of the pickup roller 231 is stopped. Then, after the skew correction is performed, the second conveyor roller 235 starts to be driven and the pickup roller 231 resumes descending.

On the other hand, if the storage case 210 is installed and a sheet is detected by the second sheet detection sensor 705 when the pickup roller 231 starts to descend, the skew correction of the drooping sheet S1 is not performed, and the second conveying roller 235 starts to be driven when the pickup roller 231 starts to descend or when the second sheet detection sensor 705 detects a sheet, as described above.

In such a case, the drooping sheet S1 hits the conveying roller pair 237 while the pickup roller 231 is descending, but 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 if the conveying roller pair 237 is not used to perform skew correction, the sheet is conveyed to the image forming device 100 after skew correction is performed on the conveying path downstream of the conveying roller pair 237 of the multi-tier storage device 200.

In this way, by driving the second conveyor 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 drooping sheet S1, and this sheet can be treated as a valid sheet as described above.

[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.

In this embodiment, the second conveyor roller 235 rotates a certain amount from the point when the second sheet detection sensor 705 detects the sheet and then stops. In other words, the control unit 203 controls the drive amount of the second conveyor 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 located at a predetermined position.

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 with the hanging sheet S1 present as described above, the hanging sheet S1 may be treated as a jammed sheet. In addition, 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 so that 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 consisting of the second conveying roller 235 and the opposing roller 236, and the hanging sheet S1 can be easily picked up by an operator who opens the door and accesses the device.

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

When there is a hanging sheet and a sheet jams during 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 the sheet fed from the other storage 210 may be provided.

[Handling of sagging sheets in response to detection by the empty sensor]
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.

Therefore, in this embodiment, even if the empty sensor 702 does not detect a sheet, if the second sheet detection sensor 705 detects a sheet due to the downward movement of the pickup roller 231, the control unit 203 determines that there is a sheet that can be fed by the pickup roller 231. In other words, if the hanging sheet S1 is detected by the second sheet detection sensor 705, the control unit 203 does not determine that the storage cabinet 210 is empty even if the empty sensor 702 does not detect the hanging sheet S1.

The operation of feeding sheets on the stacking tray 221 will now be described with reference to Figures 10(a) and (b). First, the storage 210 is attached to the mounting position of the housing 204, and with the pickup roller 231 in the lower position, the stacking tray 221 is raised by the lifting mechanism 226 (Figure 5) as shown in Figure 10(a). Then, when the top sheet on the stacking tray 221 comes into contact with the pickup roller 231 and is detected by the upper surface detection sensor 700 (Figures 5 and 7), sheet feeding begins as shown in Figure 10(b).

On the other hand, if the stacking tray 221 is raised but no sheets are detected by the empty sensor 702, the control unit 203 normally determines that there are no sheets on the stacking tray 221 and causes the display unit 206 to notify that there are no sheets in the storage cabinet 210. Of course, sheet feeding is not started either.

The detailed configuration of the empty sensor 702 of this embodiment will now 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 is configured so that the flag 702d can pass through the photointerrupter 702c when the arm 702b swings.

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.

In this configuration, as shown in FIG. 11(a), if the hanging sheet is a small-sized sheet S2 and the rear end of sheet S2 is located downstream of the tip of arm 702b of empty sensor 702, the tip of arm 702b will enter recess 221b of stack tray 221. As a result, despite the presence of a hanging sheet, sheet S2 will not be detected by empty sensor 702. For this reason, in this embodiment, when sheet S2 is detected by second sheet detection sensor 705, it is determined that a sheet is present in storage 210 regardless of the detection result of empty sensor 702, and sheet S2 can be fed.

In addition, 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 sheets on the stacking tray 221 can be fed by the pickup roller 231, if the second sheet detection sensor 705 detects a sheet due to the lowering operation of the pickup roller 231, the control unit 203 determines that there is a sheet that can be fed from the stacking tray 221.

In addition, when the empty sensor 702 does not detect a sheet 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 will notify 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 so that sheets can be easily stacked when the operator pulls out the storage case 210 to replenish sheets.

Note that even if the empty sensor 702 does not detect a sheet, if the second sheet detection sensor 705 detects 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 does not detect this sheet, the display unit 206 does not display that the storage unit 210 is empty.

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

[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 remaining sheets on any of the conveying 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 conveying path. If there are no remaining sheets on any of the conveying paths (Y in S1), the control unit 203 permits the job and starts feeding sheets (S2).

On the other hand, if there is a remaining sheet on any of the transport 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.

[Control when pulling out storage unit]
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 storage 210 is not unlocked and a message that a jam has occurred is displayed on the display unit 206 (S103).

On the other hand, if 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 control unit 203 starts lowering the stacking tray 221 toward the specified stacking position (S105). Then, the control unit 203 waits for the pickup roller 231 to finish rising to the upper position (S106), and when it is completed (Y in S106), it unlocks the storage unit 210 (S107). That is, it turns on the drawer solenoid 205a (see FIG. 7) to release the locking mechanism that locked the storage unit 210 in the mounting position. As a result, the storage unit 210 is pushed from the mounting position of the housing 204 toward the drawn position by a spring (not shown). When a certain time has elapsed since the drawer solenoid 205a was turned on (Y in S108), the control unit 203 turns off the drawer solenoid 205a (S109).

The downward movement of the stacking tray 221 continues even while the storage unit 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 unit 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.

[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.

Here, the completion of the movement of the pickup roller 231 to the lower position is determined based on the time that has elapsed since the start of movement from the upper position. In other words, when a predetermined time has elapsed since the start of movement from the upper position, it is determined that the pickup roller 231 has completed moving from the upper position to the lower position. For this reason, the control unit 203 counts the time from when the pickup roller 231 started to descend, and checks whether the predetermined time has elapsed (S204).

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 stops the rotation of the pickup roller 231, the first conveying roller 232, and the second conveying roller 235.

Next, the control unit 203 starts raising the stack tray 221 (S207) and checks whether the top surface detection sensor 700 (FIGS. 5 and 7) has turned ON (S208). When the top surface detection sensor 700 turns ON, the control unit 203 stops raising the stack tray 221 (S209). If there are sheets on the stack tray 221, the top surface detection sensor 700 detects the top sheet. On the other hand, if there are no sheets on the stack tray 221, the control unit 203 detects the stack surface of the stack tray 221.

At this time, the control unit 203 checks whether there is a sheet on the stack tray 221 using the empty sensor 702 (S210). If the empty sensor 702 detects that there is a sheet (Y in S210), the sheet can be fed by the pickup roller 231, so the control unit 203 ends control and waits for an instruction to start feeding the sheet.

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 when the pickup roller 231 descends. 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 detected the sheet (S212). In practice, the roller drive time is managed so that the sheet is conveyed a certain amount. That is, when a certain amount of time has elapsed since the second sheet detection sensor 705 detected the sheet, the drive of the first conveying roller 232 and the second conveying roller 235 is stopped.

The reason for transporting a fixed amount of sheet in this manner is, as described above, to keep the leading edge 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 can be managed so that the sheet does not interfere with sheets fed from other storage units 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.

In addition, in S210, if the empty sensor 702 does not detect a sheet (N in S210), it is checked 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 hanging sheet can be fed, so the control unit 203 ends the control and waits for an instruction to start feeding the sheet.

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 the specified stacking position (S216). The control unit 203 checks whether the stacking tray 221 has reached the specified stacking position (S217), and if it has reached the specified stacking position (Y in S216), stops the lowering of the stacking tray 221 (S218). Whether the stacking tray 221 has reached the specified stacking position (intermediate position) is determined by detecting that the stacking tray 221 has reached the specified 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 control.

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

In addition, by treating the hanging sheet as a valid sheet in this way, sheet waste can be reduced. In particular, even if the hanging sheet is a small-sized 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.

The drooping sheet as described above is conveyed by the downward movement of the pickup roller 231. In this embodiment, the upper position of the pickup roller 231 is a position that is significantly removed from the lower position so that sheets can be easily loaded onto 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 jams can be suppressed.

<Other embodiments>
In the above embodiment, the case where the sheet feeding device is the multi-tier storage device 200 has been described, but the sheet feeding device of the present invention is not limited to this, and may be one equipped with one storage case. 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.

In the above embodiment, the control unit 203 that controls the feeding motor 301 and the like is provided in the multi-tier storage device 200, but these controls may also be performed by the control unit 140 of the image forming device 100. Also, the sheet feeding device may have another configuration, such as a single deck, regardless of the above-mentioned multi-tier storage device.

200: Multi-level storage device (sheet feeding device) / 203: Control unit (judgment means) / 204: Housing (device body) / 205: Drawer button (operation means) / 206: Display unit (alert means) / 210: Storage / 221: Stacking tray / 226: Lifting mechanism (lifting means) / 230: Sheet feeding unit (feeding unit) / 231: Pickup roller (feeding roller) / 232: First conveyor roller (conveyor roller) / 235: Second conveyor roller / 300: Drive transmission mechanism (drive means) / 301: Feed motor (drive motor) / 702: Empty sensor (first detection means) / 705: Second sheet detection sensor (detection means, second detection means)

Claims (8)

A loading tray on which sheets are loaded;
a feeding section including a feeding roller that feeds the sheets stacked on the stacking tray and a conveying roller that conveys the sheets fed by the feeding roller;
A driving means for raising and lowering the feeding roller;
a detection unit for detecting a sheet downstream of the conveying roller in a sheet conveying direction;
a determination unit that determines whether or not a sheet has been jammed based on the detection state of the detection unit,
The sheet feeding device according to claim 1, wherein the determining means determines that there is no jam for the sheet detected by the detecting means while the feeding roller is moving downward. The sheet feeding device according to claim 1, characterized in that the driving means has a driving motor that rotates in one direction to lower the feeding roller and rotates the transport roller in the transport direction. The sheet feeding device according to claim 1 or 2, characterized in that the determining means determines whether a sheet is jammed and whether or not the sheet feeding operation can be performed based on the sheet detection status of the detecting means at the time when the determining means receives an instruction to start feeding. The sheet feeding device according to claim 3, in which the feeding operation is disabled if the determination means determines that a jam has occurred, and the feeding operation is enabled if the determination means determines that no jam has occurred. a storage unit provided with the loading tray and capable of being pulled out and attached to the main body of the device;
and an operating means for allowing the storage unit to be drawn out;
5. The sheet feeding device according to claim 1, wherein the determining means disables the drawer from being pulled out when the detecting means detects a sheet when the operating means is operated. a storage unit provided with the loading tray and movable between a pull-out position where the loading tray is pulled out relative to the device body and a mounting position where the loading tray is mounted to the device body;
The sheet feeding device according to any one of claims 1 to 4, characterized in that the driving means raises the feeding roller to an upper position for placing a sheet on the stacking tray before the storage case 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 stacking tray after the storage case moves to the mounting position. 7. The sheet feeding apparatus according to claim 5, wherein the feeding section is configured to be able to be pulled out and attached to the apparatus body simultaneously with the storage case. The sheet feeding device according to any one of claims 1 to 7, further comprising a notification means for notifying the user when the determination means determines that a sheet has jammed.

Images