Sheet conveying device

Abstract

To provide a sheet conveying device capable of conveying a remaining sheet, the conveying of which is stopped due to a jam or the like, to a position where the remaining sheet can be taken out according to a stopping position and basis weight of the remaining sheet.SOLUTION: A sheet conveying device includes: conveying means for conveying a sheet along a predetermined conveying path; first conveying path opening means for opening a first portion of the conveying path to allow removal of the sheet; second conveying path opening means for opening a second portion of the conveying path to allow removal of the sheet; and sheet detection means for detecting a remaining sheet stopped upstream of a position of a jammed sheet when a sheet jam occurs in the conveying path. The conveying means conveys the remaining sheet to either the first portion or the second portion of the conveying path based on a basis weight of the remaining sheet.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a sheet conveying device that conveys a sheet along a predetermined conveyance path, and more particularly, to a sheet conveying device having a function for removing residual sheets stopped in the conveyance path.

Background Art

[0002] Conventionally, in a sheet conveying device having a conveyance path for conveying a sheet, when a jam of the sheet occurs in the conveyance path of the sheet, after stopping the conveyance of the sheet, a jam processing method of opening the conveyance path to remove the jammed sheet is known. However, when there is a residual sheet whose conveyance has stopped upstream of the jammed sheet, even if the jammed sheet is removed, the residual sheet may remain in the conveyance path where it has stopped and may be difficult to remove. To improve this, Patent Document 1 discloses an apparatus provided with means for conveying the residual sheet to a position where it can be easily taken out.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In conventional apparatuses such as Patent Document 1, the structure is such that the sheet is removed from the front side facing the width direction orthogonal to the conveyance direction of the sheet. In such a structure, since the section where the conveyance path can be opened is limited, for a residual sheet longer than the opened section, the removal work has to be carried out with a part of it remaining in the conveyance path that cannot be opened. For this reason, the removal work of a thick and stiff residual sheet such as cardboard with a large basis weight becomes complicated, and in some cases, the sheet may be damaged.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet conveyance device capable of conveying a residual sheet whose conveyance has been stopped due to jam or the like to a position where the residual sheet can be taken out according to the stop position and basis weight of the residual sheet.

Means for Solving the Problems

[0006] The sheet conveyance device according to the present invention includes a conveyance means for conveying a sheet along a predetermined conveyance path, a first conveyance path opening means for enabling the sheet to be taken out by opening a first portion of the conveyance path, a second conveyance path opening means for enabling the sheet to be taken out by opening a second portion of the conveyance path, and a sheet detection means for detecting a residual sheet stopped upstream of the position of the jammed sheet when a jam of the sheet occurs in the conveyance path. The conveyance means conveys the residual sheet to either the first portion or the second portion of the conveyance path based on the basis weight of the residual sheet.

Effects of the Invention

[0007] According to the sheet conveyance device of the present invention, the sheet can be conveyed toward either the first or second portion of the conveyance path where the sheet in the conveyance path can be taken out based on the length of the sheet to be conveyed. As a result, it is possible to easily take out the residual sheet stopped in the conveyance path due to jam or the like without damaging it.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0009] Hereinafter, based on the attached drawings, the details of the sheet conveyance device of the present invention will be described. FIG. 1 schematically shows an example of an image forming system centered on the sheet conveyance device. The image forming system is composed of an image forming device A1 and a multi-stage storage device B1 which is an embodiment as a sheet conveyance device for supplying sheets to the image forming device A1. Further, a relay unit B2 for conveying the sheets fed from the multi-stage storage device B1 to the image forming device A1 is attached to the multi-stage storage device B1.

[0010] The image forming system forms a toner image (image) on a sheet in response to an image signal from a host device such as a document reading device A2 connected to the image forming device A1 or a personal computer communicably connected to the image forming device A1. In the case of this embodiment, the document reading device A2 is arranged above the image forming device A1. When reading a document, the document reading device A2 irradiates the document placed on the platen glass 3 with light from a scanning optical system light source and reads the document image by inputting the reflected light into a photoelectric conversion element CCD. Further, the document reading device A2 includes a document conveyance device A3, and it is also possible to automatically convey the document placed on the tray 5 to the reading unit of the document reading device A2 by the document conveyance device A3 and read the document image.

[0011] The image forming apparatus A1 is provided with a plurality of conveyance paths, conveyance means including a plurality of conveyance roller pairs provided along each conveyance path, a plurality of paper feed cassettes 12a and 13a for storing sheets, and paper feed mechanisms 12b and 13b for separating and feeding sheets one by one from each of the paper feed cassettes 12a and 13a. After passing through the conveyance path 16 by the plurality of conveyance roller pairs 15, it is fed into the image forming unit 11. Further, the sheet conveyed from the multi-stage storage device B1 via the relay unit B2 merges into the conveyance path 16 via the connection path 17 and then is fed into the image forming unit 11 via the conveyance roller 15.

[0012] In addition, a plurality of sheet sensors (not shown) are provided in each conveyance path of the image forming apparatus A1, and it is detected that a jam has occurred based on the position information of the sheet conveyed in each conveyance path. When a jam is detected, the sheet being conveyed is controlled to stop.

[0013] The image forming unit 11 includes a photosensitive drum 20, a charger 21, a laser scanner 22, a developing unit 23, a transfer device 24, a cleaner 25, etc. During image formation, the photosensitive drum 20 is rotationally driven. First, the surface of the photosensitive drum 20 is uniformly charged by the charger 21. Then, the charged photosensitive drum 20 is irradiated with laser light from the laser scanner 22 that emits light according to the image signal, thereby forming an electrostatic latent image on the photosensitive drum 20. Further, the electrostatic latent image formed on the photosensitive drum 20 in this way is then visualized as a toner image by the developing unit 23. After that, the toner image on the photosensitive drum 20 is transferred to a sheet by the transfer device 24. Further, the sheet onto which the toner image has been transferred in this way is conveyed to a fixing device 27 for fixing the toner image, and then discharged to a discharge tray 19 by a pair of discharge rollers 18. When forming a toner image on the back surface of the sheet, the sheet discharged from the fixing device 27 is conveyed to a reverse conveyance path 26. Then, with the front and back sides reversed by the reverse conveyance path 26, the sheet is conveyed again to the transfer device 24 of the image forming unit 11. The sheet onto which the toner image has been transferred to the back surface is conveyed to the fixing device 27, and after the toner image is fixed, it is discharged to the discharge tray 19 by the pair of discharge rollers 18. Note that the transfer residual toner remaining on the photosensitive drum 20 after transfer is removed by the cleaner 25.

[0014] FIG. 2 is an external view of the multi-stage storage device B1, FIG. 3 is a schematic cross-sectional view of the multi-stage storage device B1, and FIG. 4 is a block diagram showing the configuration of the control system of the multi-stage storage device B1. As shown in FIG. 2, the multi-stage storage device B1 includes upper, intermediate, and lower storage bins 30, 31, and 32 that can be pulled out to the front side in the figure by operation buttons 97a, 97b, and 97c. Further, on the downstream side (left side in the figure) in the sheet conveyance direction, a first front cover CA1 that is provided to be openable and closable to open a common conveyance path 37 described later, and a second front cover CA2 that is provided to be openable and closable to open a curved upper conveyance path 34 and a lower conveyance path 36 that convey the sheets fed from the upper, intermediate, and lower storage bins 30, 31, and 32 in the longitudinal direction (vertical direction).

[0015] As shown in FIG. 3, the multi-stage storage device B1 includes an upper-stage storage bin 30, a middle-stage storage bin 31, and a lower-stage storage bin 32. In this embodiment, a common conveyance path 37 is arranged between the upper-stage storage bin 30 and the middle-stage storage bin 31. Upper-stage loading trays 30a, middle-stage loading trays 31a, and lower-stage loading trays 32a for loading sheets are respectively provided in the upper-stage storage bin 30, the middle-stage storage bin 31, and the lower-stage storage bin 32. These upper-stage loading trays 30a, middle-stage loading trays 31a, and lower-stage loading trays 32a are configured to move up and down by driving corresponding lifting motors (not shown) and move the upper-stage loading trays 30a, middle-stage loading trays 31a, and lower-stage loading trays 32a to the paper feeding position and the replenishment position. The sheets in the upper-stage storage bin 30 are fed to the upper conveyance path 34, the sheets in the middle-stage storage bin 31 are fed to the middle conveyance path 35, and the sheets in the lower-stage storage bin 32 are fed to the lower conveyance path 36. The middle conveyance path 35 merges into the lower conveyance path 36 midway, and the upper conveyance path 34 and the lower conveyance path 36 are connected to a common conveyance path 39. As a result, the sheets from the upper conveyance path 34, the middle conveyance path 35, and the lower conveyance path 36 are respectively conveyed to the common conveyance path 37 and conveyed to the relay unit B2 through the common conveyance path 37 by a plurality of common conveyance roller pairs 50 to 53 provided in the common conveyance path 37. Note that the upper conveyance path 34 shown in FIG. 3 is formed to be curved in a U shape and guides the sheet fed from the sheets in the stage storage bin 30 to the common conveyance path 37.

[0016] The relay unit B2 is integrally attached to the multi-stage storage device B1 and includes a relay conveyance path 38 that conveys the sheets from the common conveyance path 37 of the multi-stage storage device B1 to the image forming device A1, and an escape path 39 that branches from the relay conveyance path 38 and discharges the double-fed sheets where two or more sheets overlap to the escape tray 100.

[0017] The multi-stage storage device B1 is provided with an upper sheet feeding unit 41 for feeding sheets from the upper storage bin 30, a middle sheet feeding unit 42 for feeding sheets from the middle storage bin 31, and a lower sheet feeding unit 43 for feeding sheets from the lower storage bin 32 in the vertical direction. The upper sheet feeding unit 41, the middle sheet feeding unit 42, and the lower sheet feeding unit 43 each have a pickup roller 41a, 42a, 43a, a sheet feeding roller 41b, 42b, 43b, and a retard roller 41c, 42c, 43c. The pickup roller 41a, the sheet feeding roller 41b, and the retard roller 41c of the upper sheet feeding unit 41 separate and feed the sheets one by one by the forward rotation drive of the upper sheet feeding motor MT1. The pickup roller 42a, the sheet feeding roller 42b, and the retard roller 42c of the middle sheet feeding unit 42 separate and feed the sheets one by one by the forward rotation drive of the middle sheet feeding motor MT2. The pickup roller 43a, the sheet feeding roller 43b, and the retard roller 43c of the lower sheet feeding unit 43 separate and feed the sheets one by one by the forward rotation drive of the lower sheet feeding motor MT3. Since the configurations of the upper sheet feeding unit 41, the middle sheet feeding unit 42, and the lower sheet feeding unit 43 are the same, the upper sheet feeding unit 41 will be described here, and the details of the middle sheet feeding unit 42 and the lower sheet feeding unit 43 will be omitted.

[0018] The upper sheet feeding unit 41 has a pickup roller 41a, a sheet feeding roller 41b, and a retard roller 41c. The pickup roller 41a, the sheet feeding roller 41b, and the retard roller 41c are arranged substantially at the center in the width direction. The pickup roller 41a feeds the sheets stored in the upper storage bin 30. Specifically, the pickup roller 41a contacts and is sent out by contacting the topmost sheet of the sheets stacked on the raised loading tray 30a. For this purpose, as shown in FIG. 3, the pickup roller 41a is arranged so as to be able to press-contact the topmost sheet on the loading tray 30a with an appropriate force near the tip of the sheet in the sheet conveyance direction. Then, the pickup roller 41a rotates by the drive of the upper sheet feeding motor MT1 as a drive source to send out the topmost sheet.

[0019] When two or more sheets are fed overlapping from the pickup roller 41a, the paper feed roller 41b and the retard roller 41c separate and convey only one sheet. That is, the paper feed roller 41b rotates in the direction of conveying the sheet by the drive of the upper paper feed motor MT1 and conveys the sheet fed from the pickup roller 41a. On the other hand, the retard roller 41c rotates in the direction opposite to that of the paper feed roller 41b and pushes back the sheets other than the top sheet among the two or more sheets sent from the pickup roller 41a toward the stacking tray 30a. Note that the retard roller 41c has a built-in torque limiter (not shown), and when only one sheet is sent from the pickup roller 41a, it is rotated by the sheet conveyed by the paper feed roller 41b.

[0020] The sheet fed in the upper paper feed section 41 is conveyed through the upper conveyance path 34 by the first and second upper conveyance roller pairs 44 and 45. Also, the sheets in the middle storage 31 are conveyed to the lower conveyance path 36 via the middle conveyance path 35 and are conveyed through the lower conveyance path 36 by the third lower conveyance roller pair 48. The sheets in the lower storage 32 are conveyed through the lower conveyance path 35 by the first, second, and third lower conveyance roller pairs 46, 47, and 48. Then, the sheets conveyed through the upper conveyance path 34, the middle conveyance path 35, and the lower conveyance path 36 are conveyed to the image forming apparatus A1 via the common conveyance path 37 on the downstream side of the first to fourth common conveyance paths 37.

[0021] In the upper conveyance path 33, a first upper conveyance roller pair 44 and a second upper conveyance roller pair 45 are provided. The first upper conveyance roller pair 46 rotates driven by a first upper conveyance motor MT4, and the second upper conveyance roller pair 45 rotates driven by a second upper conveyance motor MT5 to convey the sheet along the upper conveyance path 34. In the lower conveyance path 36, first to third lower conveyance roller pairs 46, 47, 48 are arranged. The first and second lower conveyance roller pairs 46, 47 rotate driven by a first lower conveyance motor MT6 to convey the sheet from the lower storage 32 along the lower conveyance path 36. Also, the third lower conveyance roller pair 48 rotates driven by a second lower conveyance motor MT7 to convey the sheets from the middle storage 31 and the lower storage 32 along the lower conveyance path 35. In the common conveyance path 37, first to fourth common conveyance roller pairs 50 to 53 are provided. The first to fourth conveyance roller pairs 50 to 53 rotate respectively driven by first to fourth common conveyance motors MT8 to MT11 to convey the sheet along the common conveyance path 37.

[0022] Also, in the relay conveyance path 38 of the relay unit B2, first and second relay conveyance roller pairs 54, 55 are provided, and the first and second relay conveyance roller pairs 54, 55 rotate respectively driven by first and second relay conveyance motors MT12, MT13. The first and second relay conveyance roller pairs 54, 55 convey the sheet from the common conveyance path 37 of the multi-stage storage device B1 to the image forming device A1. Also, in the escape path branched from the relay conveyance path 38, first to fourth escape conveyance roller pairs 56 to 59 are provided. The first to fourth escape conveyance roller pairs 56 to 59 rotate driven by an escape conveyance motor MT14 to discharge the double-fed sheet to the escape tray 100.

[0023] FIG. 5 is a schematic diagram showing the first, second, and third conveyance path opening means 61, 62, and 63. In the multi-stage storage device B1, the outer guide 34b is separated from the inner guide 34a that forms a vertical portion along the side surface of the device of the upper conveyance path 34 to open the vertical portion of the upper conveyance path 34. The first conveyance path opening means 61, the second conveyance path opening means 62 that enables the sheet to be taken out in the sheet width direction orthogonal to the sheet conveyance direction by opening the portion formed in the vertical direction along the side surface of the device of the lower conveyance path 36, and the third conveyance path opening means 63 that enables the sheet to be taken out in the sheet width direction orthogonal to the sheet conveyance direction by opening a part of the common conveyance path 37 are provided.

[0024] Next, each conveyance path opening means in the multi-stage storage device B1 will be described. The multi-stage storage device B1 of the present embodiment has the first conveyance path opening means 61, the second conveyance path opening means 62, and the third conveyance path opening means 63, and each is provided with a first outlet 61a as the first sheet take-out portion, a second outlet 62a as the second sheet take-out portion, and a third outlet 63a as the third sheet take-out portion. The first conveyance path opening means 61 is configured to be able to take out the sheet remaining in the common conveyance path 39. The first conveyance path opening means 61 is movable to a position where a part of the common conveyance path 37 is opened. At least a part of the common conveyance path 37 is composed of a first common conveyance guide 37a and a second common conveyance guide 37b facing the first common conveyance guide 37a. One roller 50b, 51b, 52b, 53b of the first to fourth roller pairs 50 to 53 arranged in the common conveyance path 37 is attached to the second common conveyance guide 37b. Further, the second common conveyance guide 37b rotates about a fulcrum on the back side of the device in the sheet width direction orthogonal to the sheet conveyance direction. In the multi-stage storage device B1, when the second common conveyance guide 37b rotates, the second common conveyance guide 37b and one roller 50b, 51b, 52b, 53b of each of the first to fourth common conveyance roller pairs 50 to 53 move downward away from the first common conveyance guide 37a and the other rollers 50a, 51a, 52a, 53a, and a part of the common conveyance path 37 is opened.

[0025] When removing the sheet whose conveyance has stopped in the common conveyance path 37 due to the occurrence of a jam, the first opening cover CA1 shown in Fig. 2 is rotated toward the front side of the apparatus (the front side in the figure) with its lower end as a fulcrum to expose the common conveyance path 37, and then the handle 65 is manually operated downward. As a result, as shown in Fig. 5, the second common conveyance guide 37b rotates about the rear side of the apparatus as a fulcrum, a part of the common conveyance path 37 is opened, and the sheet remaining in the common conveyance path 37 can be removed.

[0026] The second conveyance path opening means 62 is movable to a position where a part of the upper conveyance path 34 is opened. The portion formed in the vertical direction of the upper conveyance path 34 is composed of a first upper conveyance guide 34a and a second upper conveyance guide 34b facing the first upper conveyance guide 34a. One roller 44a of the first upper conveyance roller pair 44 and one roller 45b of the second upper conveyance roller pair 45 disposed in the upper conveyance path 34 are attached to the second upper conveyance guide 34b. Further, the second upper conveyance guide 34b rotates about the rear side of the apparatus in the sheet width direction orthogonal to the sheet conveyance direction as a fulcrum. In the multi-stage storage device B1, when the second upper conveyance guide 34b rotates, the second upper conveyance guide 34b and one roller 44b, 45b of the first and second upper conveyance roller pairs 44, 45 move away from the first upper conveyance guide 34a and the other rollers 44a, 45a of the first and second upper conveyance roller pairs 44, 45 toward the side surface side of the multi-stage storage device B1, and the vertical portion of the upper conveyance path 34 is opened.

[0027] When removing the sheet whose conveyance has stopped in the upper conveyance path 34 due to the occurrence of a jam, the second opening cover CA2 shown in Fig. 2 is rotated toward the side surface side of the multi-stage storage device B1 (the right side in Fig. 2) with the end on the side surface side in the multi-stage storage device B1 as a fulcrum to expose the upper conveyance path 34, and then the handle 66 is manually operated toward the side surface side of the multi-stage storage device B1. As a result, as shown in Fig. 5, the second upper conveyance guide 34b rotates toward the side surface side of the multi-stage storage device B1 about the rear side of the apparatus as a fulcrum, the vertical portion of the upper conveyance path 34 is opened, and the sheet remaining in the upper conveyance path 34 can be removed.

[0028] The third conveyance path opening means 63 is movable to a position where a part of the lower conveyance path 36 is opened. The portion formed in the vertical direction of the lower conveyance path 36 is composed of a first lower conveyance guide 36a and a second lower conveyance guide 36b facing the first lower conveyance guide 36a. One roller 46b of the first lower conveyance roller pair 46, one roller 47b of the second lower conveyance roller pair 47, and one roller 48b of the third lower conveyance roller pair 48 arranged in the lower conveyance path 36 are attached to the second lower conveyance guide 36b. Further, the second lower conveyance guide 36b rotates about a fulcrum on the back side of the apparatus in the sheet width direction orthogonal to the sheet conveyance direction. In the multi-stage storage device B1, when the second lower conveyance guide 36b rotates, the second lower conveyance guide 36b and one roller 46b, 47b, 48b of each of the first to third upper conveyance roller pairs 46 to 48 are separated from the first lower conveyance guide 36a and the other rollers 46a, 47a, 48a of each of the first to third upper conveyance roller pairs 46 to 48 toward the side surface of the multi-stage storage device B1, and the vertical portion of the lower conveyance path 36 is opened.

[0029] When removing a sheet whose conveyance has stopped in the lower conveyance path 36 due to the occurrence of a jam, the second opening cover CA2 shown in FIG. 2 is rotated toward the side surface of the multi-stage storage device B1 (the right side in FIG. 2) about the end on the side surface of the multi-stage storage device B1 as a fulcrum, and after the lower conveyance path 36 is exposed, the handle 67 is manually operated toward the side surface of the multi-stage storage device B1. As a result, as shown in FIG. 5, the second lower conveyance guide 34b rotates toward the side surface of the multi-stage storage device B1 about the back side of the apparatus as a fulcrum, the vertical portion of the lower conveyance path 36 is opened, and the sheet remaining in the lower conveyance path 36 can be removed.

[0030] The control unit CON acquires information such as the sheet feeding timing, the type of sheet to be conveyed (including size, basis weight, etc.), and the position during conveyance by communicating with the image forming apparatus A1. The multi-stage storage device B1 is provided with a plurality of sheet detection means (detection sensors) S1 to S12 for detecting the conveyed sheets, and a plurality of motors MT1 to MT14 for driving the respective rollers arranged in the respective conveyance paths 33 to 39. The control unit CON controls the respective motors MT1 to MT14 according to the detection state of the sheets by the plurality of sheet sensors S1 to S12, and executes the sheet conveyance operation. Further, when a jam is detected in the image forming apparatus A1, the information is transmitted to the control unit CON, and the conveyance of the sheets in the multi-stage storage device B1 and the conveyance of the sheets in the sheet feeding device B2 and the relay unit B2 are stopped. Then, the sheets (residual sheets) left behind by this stop are detected by the sheet sensors S1 to S10 described later, and based on the result, they are controlled to be conveyed toward the first, second, or third conveyance path opening means 61, 62, 63. Further, the control unit CON detects a jam from the detection state of the sheets by the plurality of sheet detection means (detection sensors) S1 to S12, and stops the conveyance of the sheets in the multi-stage storage device B1 and the conveyance of the sheets in the sheet feeding device B2 and the relay unit B2.

[0031] In the present embodiment, when a jam occurs in the image forming apparatus A1, the multi-stage storage device B1 temporarily stops its operation. As a result, the conveyance of the sheets in each conveyance path in the multi-stage storage device B1 temporarily stops, so the sheets left behind in each conveyance path become residual sheets. When a jam is detected in the image forming apparatus A1, it is detected whether there are residual sheets in the multi-stage storage device B1. Whether there are residual sheets can be determined based on the detection results of the plurality of sheet sensors S1 to S12, and the location where the sheets stopped can also be specified. On the other hand, when a jam occurs in the multi-stage storage device B1, the sheets in the conveyance path upstream of the position where the jam occurred are stopped.

[0032] Next, the operation when jam occurs will be described. As shown in FIG. 5, the residual sheet generated when jam occurs can be taken out from either the first outlet 61a provided in the first conveyance path opening means 61, the second outlet 62a provided in the second conveyance path opening means 62, or the second outlet 63a provided in the third conveyance path opening means 63. The first conveyance path opening means 61 has a structure in which a long straight path can be opened with respect to the second conveyance path opening means 62 and the third conveyance path opening means 63, and it is easier to take out the residual sheet than the second conveyance path opening means 62 and the third conveyance path opening means 63. The residual sheet is conveyed to either the first conveyance path opening means 61, the second conveyance path opening means 62, or the third conveyance path opening means 63 according to the basis weight (thickness) of the residual sheet set via communication with the image forming apparatus A1. That is, when the set residual sheet is below a predetermined basis weight, the residual sheet is conveyed toward the second outlet 62a (the second conveyance path opening means 62) or the third outlet 63a (the third conveyance path opening means 63), and when it is smaller than the predetermined basis weight of the set residual sheet, the residual sheet is conveyed to the first outlet 61a (the first conveyance path opening means 61).

[0033] In the present embodiment, as means for detecting the position of the residual sheet, a plurality of detection sensors S1 to S12 are provided. The first to third detection sensors S1 to S3 are arranged on the upper conveyance path 34, the fourth detection sensor S4 is arranged on the middle conveyance path 35, the fifth to seventh detection sensors S5 to S7 are arranged on the lower conveyance path 36, and the eighth to tenth detection sensors S8 to S10 are arranged on the common conveyance path 37.

[0034] Hereinafter, an embodiment of the detection and removal process of the residual sheet will be described with reference to FIGS. 6, 7, 8, and 9. FIG. 6 is a flowchart showing the process of the retained sheet. FIG. 7 is a flowchart showing the process of the retained sheet in the common conveyance path 37. FIG. 8 is a flowchart showing the process of the retained sheet in the upstream conveyance path 34. FIG. 9 is a schematic diagram showing the conveyance state of the sheet in the process of the retained sheet in the upstream conveyance path 34.

[0035] First, as described above, when a jam occurs in the image forming apparatus A1, the conveyance of sheets in each conveyance path in the multi-stage storage apparatus B1 is temporarily stopped. Then, a stuck sheet process for removing the stuck sheets is executed. In the stuck sheet process, as shown in FIG. 6, the common conveyance path stuck sheet process, the upstream conveyance path stuck sheet process, the middle stage conveyance path stuck sheet process, and the downstream conveyance path stuck sheet process are executed in this order (ST10 to ST13).

[0036] In the common conveyance path stuck sheet process, as shown in FIG. 7, first, it is confirmed whether the tenth detection sensor S10 disposed downstream of the common conveyance path 37 detects a sheet (ST10-1). If the tenth detection sensor S10 detects (ON) a sheet, there is a remaining sheet at the position of the tenth detection sensor S10, and the user is notified that the remaining sheet can be taken out from the first outlet 61a so as to take out the remaining sheet (ST10-6).

[0037] On the other hand, if the tenth detection sensor S10 does not detect (OFF) a sheet, it is assumed that there is no remaining sheet at the position of the tenth detection sensor S10, and it is confirmed whether any of the eighth and ninth detection sensors S8 and S9 detect a sheet (ST10-2). If the eighth and ninth detection sensors S8 and S9 detect (ON) a sheet, it is assumed that there is a stuck sheet outside the downstream part in the common conveyance path 37, and the first to fourth common conveyance motors MT8 to MT11 are driven to rotate the first to fourth common conveyance roller pairs 50 to 53, and the stuck sheet is conveyed along the common conveyance path 37. Then, when the tenth detection sensor S10 detects (ON) the leading end of the remaining sheet, the driving of the first to fourth common conveyance motors MT8 to MT11 is stopped to stop the rotation of the first to fourth common conveyance roller pairs 50 to 53, and the conveyance of the sheet is stopped (ST10-5). As a result, the remaining sheet is conveyed to a position where it can be taken out from the first outlet 61a. When the stuck sheet is stopped at the position where its leading end is detected by the tenth detection sensor S10, the user is notified that the remaining sheet can be taken out from the first outlet 61a so as to take out the remaining sheet (ST10-6).

[0038] In the upper conveyor path retention sheet process, as shown in FIG. 8, first, it is confirmed whether or not the third detection sensor S3 disposed downstream of the upper conveyor path 34 detects a sheet (ST11-1). If the third detection sensor S3 does not detect the sheet (OFF), it is assumed that there is no remaining sheet at the position of the third detection sensor S3, and it is confirmed whether or not the first and second detection sensors S1 and S2 detect the sheet (ST11-2). When any one of the third detection sensor S3 and the first and second detection sensors S1 and S2 detects the sheet (ON) (see FIG. 9(a)), it is confirmed whether or not the basis weight of the sheet is below a predetermined value (ST11-3). When the basis weight is below the predetermined value, the upper sheet feeding motor MT1 and the first upper conveyor motor MT4 are driven to rotate the upper sheet feeding roller 41b and the first upper conveyor roller pair 44 to convey the remaining sheet (ST11-4). Then, when the third detection sensor S3 detects the sheet, the driving of the upper sheet feeding motor MT1 and the first upper conveyor motor MT4 is stopped to stop the rotation of the upper sheet feeding roller 41b and the first upper conveyor roller pair 44 and stop the conveyance of the remaining sheet (ST11-5, ST11-6). When conveying the remaining sheet, if the third detection sensor S3 detects the sheet in step 11-1, since the third detection sensor S3 already detects the sheet, the sheet is not substantially conveyed. As a result, the remaining sheet stops at the position where its leading end is detected by the third detection sensor S3, and the remaining sheet is in a position where it can be easily taken out from the second outlet 62a (see FIG. 9(b)). Then, when the conveyance of the remaining sheet is stopped, the user is notified to take it out from the second outlet 62a (ST10-7).

[0039] On the other hand, when the sheet area is larger than a predetermined value, the upper sheet feeding motor MT1, the first upper conveyance motor MT4, the second upper conveyance motor MT5, and the first to fourth common conveyance motors MT8 to MT11 are driven to rotate the upper sheet feeding roller 41b, the first and second upper conveyance roller pairs 44 and 45, and the first to fourth common conveyance roller pairs 50 to 53, and the remaining sheet is conveyed along the upper conveyance path 34 and the common conveyance path 37 (ST11-8). Then, when the tenth detection sensor S10 detects (ON) the leading edge of the remaining sheet, the driving of the upper sheet feeding motor MT1, the first upper conveyance motor MT4, the second upper conveyance motor MT5, and the first to fourth common conveyance motors MT8 to MT11 is stopped to stop the rotation of the upper sheet feeding roller 41b, the first and second upper conveyance roller pairs 44 and 45, and the first to fourth common conveyance roller pairs 50 to 53, and the conveyance of the sheet is stopped (ST11-9, ST11-10). As a result, the remaining sheet is conveyed to a position where it can be taken out from the first outlet 61a (see Fig. 9(c)). When the remaining sheet is stopped at the position where its leading edge is detected by the tenth detection sensor S10, the user is notified to take out the remaining sheet so that the remaining sheet can be taken out from the first outlet 61a (ST11-11).

[0040] Regarding the remaining sheet processing in the middle conveyance path, briefly explained, when a remaining sheet is detected in the middle conveyance path 35 and the lower conveyance path 36, if the sheet area of the detected remaining sheet is equal to or less than a predetermined value, the sheet is conveyed to the position where the seventh detection sensor S7 detects it, and the remaining sheet is taken out from the third outlet 63a. At this time, the user is notified to take out the sheet from the third outlet 63a. On the other hand, when the sheet area of the detected remaining sheet is larger than a predetermined value, the sheet is conveyed to the position where the tenth detection sensor S10 detects it, and the remaining sheet is taken out from the first outlet 61a. At this time, the user is notified to take out the sheet from the first outlet 61a.

Explanation of Signs

[0041] A1 Image forming apparatus B1 Multi-stage storage device B2 Relay unit CA1 Front cover CA2 Second Front Cover 30 Upper Storage Compartment 31 Middle Storage Compartment 32 Lower Storage Compartment 34 Upper Conveyor Path 35 Middle Conveyor Path 36 Lower Conveyor Path 37 Common Conveyor Path 38 Relay Conveyor Path 39 Escape Path S1~S12 Detection Sensors

Claims

1. Conveying means for conveying a sheet along a predetermined conveyance path, first conveyance path opening means for enabling the removal of the sheet by opening a first portion of the conveyance path, second conveyance path opening means for enabling the removal of the sheet by opening a second portion of the conveyance path, and sheet detection means for detecting a residual sheet that has stopped upstream of the position of the jammed sheet when a jam occurs in the sheet in the conveyance path. The conveying means is a sheet conveying device that conveys the residual sheet to either the first portion or the second portion of the conveyance path based on the basis weight of the residual sheet.

2. The sheet conveying device according to claim 1, wherein the conveying means conveys the residual sheet to the first portion of the conveyance path when the residual sheet is equal to or more than a predetermined basis weight, and conveys the residual sheet to the second portion of the conveyance path when the residual sheet is less than the predetermined basis weight.

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