Sheet conveyance device, and image processing device including sheet conveyance device

Abstract

To provide a sheet conveyance device capable of detecting presence / absence of a foreign object in a feeding tray easily and surely with a simple structure, and to provide an image processing device including the sheet conveyance device.SOLUTION: In an image forming device 100, a control part 2 determines whether or not, during the rise of a paper feeding tray 44, an ON signal is received from a jump up detection sensor 28 (S13), and in the case where the ON signal is received from the jump up detection sensor 28, the control part determines that there is a foreign object in the paper feeding tray 44, and after that, movement to the upper part of the paper feeding tray 44 is stopped (S131).SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a sheet transport device that transports a sheet. [Background technology]

[0002] There is known a document transport device that transports a document (sheet) to a reading position of an image reading device. The document transport device includes, for example, a feed tray on which documents are stacked, a discharge tray provided below the feed tray, and a transport mechanism that transports the document along a transport path from the feed tray to the reading position of the document reading device and the discharge tray. A paper discharge outlet is formed at the downstream end of the transport path in the transport direction, and the document is discharged from the paper discharge outlet to the discharge tray.

[0003] As an example of such an original transport device, there is disclosed an original transport device capable of raising and lowering a paper feed tray to a position according to the thickness or number of originals placed on the feed tray (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-95258 Summary of the Invention [Problem to be solved by the invention]

[0005] In a document transport device capable of raising and lowering a feed tray, if there is a foreign object other than a document on the feed tray, the foreign object may be caught in a housing such as a cover or frame of the document transport device when the feed tray is raised, causing damage to the housing. Also, in the process of transporting a document from the feed tray, the foreign object may get into the transport mechanism and cause damage to the transport mechanism.

[0006] An object of the present invention is to provide a sheet conveying device capable of easily and surely detecting the presence or absence of foreign matter on a feeding tray with a simple configuration, and an image processing apparatus including the sheet conveying device.

Means for Solving the Problems

[0007] A sheet conveying device according to one aspect of the present invention includes a feeding tray on which sheets are stacked, a conveying mechanism that conveys the sheets along a conveying path from the feeding tray to a discharge tray, a lifting mechanism including a driving unit that moves the feeding tray up and down in the vertical direction, a lifting control unit that drives the driving unit to control the lifting of the feeding tray, a sensor that detects the upward bounce of an end portion on the downstream side in the feeding direction of a sheet fed from the feeding tray, and a first determination processing unit that determines whether there is foreign matter other than the sheet on the feeding tray based on an output signal of the sensor during the lifting of the feeding tray by the lifting control unit before the feeding of the sheet by the conveying mechanism, and a second determination processing unit that determines that the fed sheet is abnormal based on a change in the output signal of the sensor during the feeding of the sheet by the conveying mechanism.

[0008] An image processing apparatus according to another aspect of the present invention includes the sheet conveying device and an image processing unit that performs image processing on a sheet conveyed by the sheet conveying device.

Effects of the Invention

[0009] According to the present invention, it is possible to easily and surely detect foreign matter on the feeding tray with a simple configuration.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. Note that the embodiments described below are merely examples embodying the present invention and do not limit the technical scope of the present invention.

[0012] FIG. 1 is a diagram showing the internal configuration of an image forming apparatus 100 including a document conveying device 120 according to an embodiment of the present invention. Note that the document conveying device 120 is an example of a sheet conveying device of the present invention. Further, the image forming apparatus 100 is an example of an image processing apparatus of the present invention.

[0013] Hereinafter, the front side (front) of the image forming apparatus 100 is defined as the side of the paper surface in FIG. 1 facing the viewer, and the left and right directions are described with reference to the direction of viewing the image forming apparatus 100 from the front. Also, in each figure, U, Lo, L, R, Fr, and Rr indicate up, down, left, right, front, and rear, respectively.

[0014] The image forming apparatus 100 includes a printer 1, a document conveyance device 120 that conveys a document G (an example of a sheet of the present invention), a scanner 110 (an example of an image processing unit of the present invention) that performs image reading processing on the document G, and a control unit 2 that comprehensively controls these components. The scanner 110 is provided above the printer 1, and the document conveyance device 120 is provided above the scanner 110. The document conveyance device 120 conveys the document G via the reading position A of the scanner 110. The scanner 110 is a flatbed type image scanner that reads the image of the document G and generates image data. The printer 1 forms an image based on the image data on a sheet S. In this embodiment, an example is shown in which the printer 1 forms an image by an electrophotographic method, but the printer 1 may be configured to form an image by another method (for example, an inkjet method).

[0015] Note that the image processing apparatus of the present invention may be an image reading apparatus including the document conveyance device 120 and the scanner 110.

[0016] The printer 1 includes a rectangular parallelepiped main body housing 3. Inside the lower part of the main body housing 3, there are provided a paper feed cassette 4 for accommodating the sheet S and a paper feed roller 5 for feeding the sheet S to the right from the paper feed cassette 4. Above the paper feed cassette 4, there is provided an image forming device 6 for forming a toner image by an electrophotographic method, and above the upper right of the image forming device 6, there is provided a fixing device 7 for fixing the toner image on the sheet S. Above the fixing device 7, there are provided a discharge roller 8 for discharging the sheet S on which the toner image is fixed and a discharge tray 9 on which the discharged sheets S are stacked.

[0017] Inside the main body housing 3, a conveyance path 10 is provided that extends from the paper feed roller 5 through the image forming device 6 and the fixing device 7 to the discharge roller 8. The conveyance path 10 is mainly formed by plate-like members that face each other with a gap for passing the sheet S. A plurality of conveyance rollers 17 that sandwich and convey the sheet S are provided at appropriate intervals along the conveyance path 10. A registration roller 18 is provided upstream of the image forming device 6 in the conveyance direction Y. To the right of the fixing device 7, a reverse conveyance path 10R is provided that branches off from the conveyance path 10 downstream of the fixing device 7 in the conveyance direction Y and merges into the conveyance path 10 upstream of the registration roller 18 in the conveyance direction Y.

[0018] A display operation unit (not shown) is provided on the front side of the scanner 110. The display operation unit includes a display panel, a touch panel provided on the display surface of the display panel, and a keypad adjacent to the display panel (not shown).

[0019] The control unit 2 controls the operation of the image forming apparatus 100. The control unit 2 causes the display panel to display a screen representing the operation menu and status of the printer 1 and the scanner 110, and controls each part of the printer 1, the scanner 110, and the document conveyance apparatus 120 according to the operations detected by the touch panel and the keypad.

[0020] The basic image forming operation of the printer 1 is as follows. When a printing job for single-sided printing is input to the printer 1 from the display operation unit or an external computer or the like, the paper feed roller 5 sends out the sheet S from the paper feed cassette 4 to the conveyance path 10, the registration roller 18 whose rotation has stopped corrects the skew of the sheet S, and the registration roller 18 sends out the sheet S to the image forming device 6 at a predetermined timing. The image forming device 6 forms a toner image on the sheet S by an electrophotographic method. Subsequently, the fixing device 7 sandwiches and conveys the sheet S while melting the toner image to fix the toner image on the sheet S, and the discharge roller 8 discharges the sheet S to the discharge tray 9. In the case of double-sided printing, the sheet S with the toner image fixed on the first side is fed into the conveyance path 10 via the reverse conveyance path 10R, so that the toner image is transferred to the second side.

[0021] [Scanner 110] Scanner 110 includes a first carriage 81 having a light source and a reflecting mirror, a second carriage 82 having two reflecting mirrors, a lens 83 for imaging light, an image sensor 84 for converting the imaged light into image data, and a contact glass 85 on which a document G is placed.

[0022] The basic document reading operation of Scanner 110 is as follows. When the user places a document G on the upper surface of the contact glass 85 and gives an instruction to Scanner 110 to read, in conjunction with the first carriage 81 moving rightward at a speed V, the second carriage 82 moves rightward at a speed of V / 2. During this time, the light source irradiates the document G with light, and the reflected light reflected by the document G is reflected by the reflecting mirrors of the first carriage 81 and the second carriage 82 and guided to the lens 83, where it is imaged on the image sensor 84 and converted into an image signal. The image signal is output to the control unit 2 of the image forming apparatus 100 and converted into image data.

[0023] Also, when the user places one or more documents G on the paper feed tray 44 and gives an instruction to Scanner 110 to read, with the first carriage 81 positioned at the home position below the reading position A, Scanner 110 starts feeding the document G by the document conveying apparatus 120. Then, when the document G being conveyed passes through the reading position A, the light source irradiates the document G with light, and the reflected light reflected by the document G is reflected by the reflecting mirrors of the first carriage 81 and the second carriage 82 and guided to the lens 83, where it is imaged on the image sensor 84 and converted into an image signal. The image signal is output to the control unit 2 of the image forming apparatus 100 and converted into image data.

[0024] [Document conveying apparatus 120] Next, the document conveyance device 120 will be described. FIG. 2 is a perspective view showing the appearance of the document conveyance device 120. FIGS. 3 to 5 are diagrams schematically showing the internal configuration of the document conveyance device 120. Here, FIG. 3 shows a state in which a paper feed tray 44 (an example of the feed tray of the present invention) described later is arranged at the initial position. FIG. 4 shows a state in which the paper feed tray 44 is lifted from the initial position and arranged at the paper feed position. FIG. 5 shows a state in which the discharge guide portion 66 is arranged at a dischargeable position where the document G can be discharged.

[0025] The document conveyance device 120 includes a paper feed tray 44 (an example of the feed tray of the present invention), a paper discharge tray 43 (an example of the discharge tray of the present invention), a paper feed mechanism 31, a conveyance mechanism 32, a discharge mechanism 36, a first elevating mechanism 90 (an example of the elevating mechanism of the present invention), a second elevating mechanism 70, a holder detection sensor 58, a document detection sensor 29, a swing drive amount measurement unit 16 (see FIG. 6), and a paper discharge document sensor 21. The paper feed mechanism 31, the conveyance mechanism 32, and the discharge mechanism 36 are an example of the conveyance mechanism of the present invention that conveys a document from the paper feed tray 44 to the paper discharge tray 43.

[0026] In the present embodiment, the control unit 2 (see FIG. 1) calculates the height position of the upper surface of the document G based on the distance from the upper surface of the document G on the paper discharge tray 43 measured by the upper surface distance measurement unit 19, and moves the discharge guide portion 66 of the discharge mechanism 36 in the vertical direction by the second elevating mechanism 70 according to the height position, so as to control the difference in height between the discharge port 69 and the upper surface of the document G stacked on the paper discharge tray 43 to be within a predetermined range.

[0027] As shown in FIGS. 2 and 3, the document conveying device 120 has a generally rectangular bottom portion 40 formed in a flat shape, and a first wall portion 41 and a second wall portion 42 that face each other in the front-rear direction (width direction intersecting the conveying direction Z of the document G). The rear edge portion of the bottom portion 40 is hinge-coupled behind the contact glass 85 (see FIG. 1) of the scanner 110. The bottom portion 40 also serves as a pressing plate that presses the document G on the contact glass 85. The first wall portion 41 is provided from the left end portion to the central portion of the front edge portion of the bottom portion 40. The second wall portion 42 is provided over the entire rear edge portion of the bottom portion 40. The cover portion 46 covers the upper portion and the left side portion of the space between the first wall portion 41 and the second wall portion 42. The lower left end portion of the cover portion 46 is hinge-coupled to the left end portion of the bottom portion 40.

[0028] [Paper Feed Tray 44] The paper feed tray 44 is a document placement portion on which the document G to be conveyed is placed. The paper feed tray 44 is provided on the right side of the center in the left-right direction of the document conveying device 120 and on the front side of the second wall portion 42. The document G to be conveyed is placed on the paper feed tray 44. The paper feed tray 44 is a plate-like member inclined so that the left side is lower. A plate-like cover frame (not shown) is provided on the left side of the left end portion of the paper feed tray 44 to prevent the downward exposure of a retard roller 57 described later. Both the front and rear end portions of the cover frame are fixed to the first wall portion 41 and the second wall portion 42 (see FIG. 2). A paper feed wall portion (not shown) extending in the vertical direction is provided at the right end portion of the cover frame. The leftward movement of the document G stacked on the paper feed tray 44 is restricted by this paper feed wall portion. Note that the cover frame 47 may be a holder for holding the retard roller 57 from below.

[0029] A pair of cursors 45 for aligning the front and rear end portions of the document G are provided on the upper surface of the paper feed tray 44. The cursors 45 are slidable in the front-rear direction.

[0030] [Paper Discharge Tray 43] The paper discharge tray 43 is a document storage unit that stores the document G discharged through the conveyance path 61 and the discharge path 65 on the stacking surface. The paper discharge tray 43 is provided below the paper feed tray 44. The paper discharge tray 43 is integral with the bottom portion 40. An inclined surface that slopes downward on the left side is provided at the center of the paper discharge tray 43 in the left-right direction.

[0031] [Paper feeding mechanism 31] The paper feeding mechanism 31 takes out the document G placed on the paper feed tray 44 one by one and feeds it to the conveyance path 61. As shown in FIG. 3, the paper feeding mechanism 31 is provided in the space between the first wall portion 41 and the second wall portion 42. The paper feeding mechanism 31 includes a box-shaped holder 53 with an open lower part. Inside the holder 53, a feeding roller 51, a driven roller 55, a driving roller 52, an endless belt 56, and a retard roller 57 are arranged with the front-rear direction as the axial direction. The driven roller 55 is provided to the left of the feeding roller 51. The driving roller 52 is provided to the left of the driven roller 55. The endless belt 56 is wound around the driving roller 52 and the driven roller 55. The retard roller 57 is pressed against the lower surface of the lower portion of the endless belt 56.

[0032] Both front and rear end portions of the drive shaft 54 of the driving roller 52 are supported by the first wall portion 41 and the second wall portion 42. The drive shaft 54 is connected to a drive unit (not shown) including a motor and a reduction gear. The holder 53 is supported by the drive shaft 54 and is swingable about the drive shaft 54. The driving force of the drive shaft 54 is transmitted to the feeding roller 51 and the retard roller 57 by a transmission mechanism (not shown) such as a gear train or an endless belt.

[0033] [Holder detection sensor 58] The holder detection sensor 58 is provided on the inner surface of the cover portion 46. The holder detection sensor 58 is used to determine whether the paper feed tray 44 is disposed at a position (paper feed position) where the placed document G can be fed. The holder detection sensor 58 is, for example, a transmissive or reflective optical sensor. When the holder detection sensor 58 is a transmissive optical sensor, a light shielding plate 59 protruding upward or laterally is provided above the holder 53. When the holder detection sensor 58 is a reflective optical sensor, a reflector is provided above the holder 53.

[0034] When no document G is placed on the paper feed tray 44, the holder 53 holds the first posture (the posture shown in FIG. 3) in which the roller surface of the feed roller 51 is closest to the upper surface of the paper feed tray 44. When one or more documents G are placed on the paper feed tray 44 and the document G is detected by the document detection sensor 29, the control unit 2 drives and controls the first elevating mechanism 90 to raise the paper feed tray 44 from the initial position. Then, during the raising, when the upper surface of the document G on the paper feed tray 44 abuts on the feed roller 51 and the holder 53 is pressed upward, the feed roller 51 is lifted upward, and thereby the holder 53 is also displaced upward.

[0035] When the holder detection sensor 58 is transmissive, the upward displacement of the holder 53 causes the light shielding plate 59 to enter the detection area of the holder detection sensor 58. The amount of entry is proportional to the amount of the document G placed on the paper feed tray 44. The holder detection sensor 58 outputs a document detection signal having a signal level corresponding to the amount of entry of the light shielding plate 59 to the control unit 2. The control unit 2 determines whether the paper feed tray 44 is at the paper feed position based on the signal level of the document detection signal.

[0036] Specifically, when the signal level of the manuscript detection signal becomes less than a predetermined threshold value, the control unit 2 determines that the paper feed tray 44 has reached the feeding position. And when it is determined that the paper feed tray 44 is at the feeding position, the control unit 2 stops the ascent of the paper feed tray 44. Thereby, the paper feed tray 44 is held at the feeding position. When the manuscript G on the paper feed tray 44 is fed and decreases, the holder 53 is displaced downward by its own weight. As a result, the signal level of the manuscript detection signal becomes equal to or higher than the threshold value. In this case, the control unit 2 drives and controls the first elevating mechanism 90 again to raise the paper feed tray 44, and when the signal level of the manuscript detection signal becomes less than a predetermined threshold value, the paper feed tray 44 is stopped.

[0037] [Manuscript detection sensor 29] The manuscript detection sensor 29 (see FIG. 3) detects the presence or absence of the manuscript G on the paper feed tray 44. The manuscript detection sensor 29 is provided on the paper feed tray 44. The manuscript detection sensor 29 is, for example, a reflective optical sensor having a light emitting element and a light receiving element. The manuscript detection sensor 29 is disposed near the downstream end in the feeding direction on the upper surface of the paper feed tray 44. When the manuscript G is placed on the paper feed tray 44, the light emitted from the light emitting element is reflected by the manuscript G. When the reflected light is received by the light receiving element, the manuscript detection sensor 29 outputs an ON signal to the control unit 2 as a detection signal indicating that the manuscript G has been detected. On the other hand, when the manuscript G is not placed on the paper feed tray 44, the light emitted from the light emitting element is not reflected by the manuscript G, so it is not received by the light receiving element, and the manuscript detection sensor 29 outputs an off signal to the control unit 2 as a detection signal indicating that the manuscript G has not been detected. The control unit 2 determines the presence or absence of the manuscript G on the paper feed tray 44 based on the detection signal output from the manuscript detection sensor 29.

[0038] [First elevating mechanism 90] The first lifting mechanism 90 has a function of lifting the paper feed tray 44. The first lifting mechanism 90 lifts the paper feed tray 44 between the initial position (the position shown in Fig. 3), which is the lowest position, and the paper feeding position (the position shown in Fig. 4). As shown in Fig. 2, the first lifting mechanism 90 includes a rack 91, a pinion 92, and a drive unit 93 such as a motor (see Fig. 6). In the present embodiment, a pair of the rack 91 and the pinion 92 are provided on both front and rear sides with the paper feeding mechanism 31 interposed therebetween. In Figs. 3 to 5, only one of the rack 91 and the pinion 92 on the front side is shown.

[0039] The rack 91 is fixed to a side portion of a frame (not shown) that supports the paper feeding mechanism 31, the conveying mechanism 32, the discharging mechanism 36, etc. The pinion 92 is rotatably supported around an axis on a side portion of the paper feed tray 44. The pair of left and right pinions 92 are connected by a shaft (not shown). One of the pinions 92 is connected to the output shaft of the drive unit 93 (see Fig. 6) via a power transmission mechanism such as a gear train. For example, the rack 91 is formed in a substantially inverted U shape having internal teeth 91A, and the pinion 92 meshes with the internal teeth of the rack 91. The drive unit 93 is electrically connected to the control unit 2. The pinion 92 is rotationally driven by the drive unit 93 and moves in the vertical direction while meshing with the rack 91. As a result, as the pinion 92 moves, the paper feed tray 44 moves in the same direction as the moving direction of the pinion 92.

[0040] In the present embodiment, the discharge guide portion 66 of the discharging mechanism 36 described later is configured to be movable in the vertical direction by the second lifting mechanism 70. However, for example, instead of providing the second lifting mechanism 70, a link member (not shown) that connects the paper feed tray 44 and the discharge guide portion 66 may be provided, and the discharge guide portion 66 may be moved in the vertical direction in conjunction with the vertical movement of the paper feed tray 44.

[0041] [Pop-up detection sensor 28] The bounce-up detection sensor 28 is provided on the lower surface of the right end portion of the cover part 46. The bounce-up detection sensor 28 is a sensor for detecting that the rear end portion of the document G has bounced upward when the document G is fed. Further, the bounce-up detection sensor 28 is also used as a sensor for detecting foreign matter on the paper feed tray 44.

[0042] For example, when the uppermost document G1 placed on the paper feed tray 44 and the next document G2 are stapled together, when a feeding operation is performed on the document G1, the stapled portion at the rear end is pulled and bounces upward, and the document G1 is lifted above the normal position during paper feeding (see the dashed line in FIG. 4). The bounce-up detection sensor 28 is provided to detect the document G1 in such a state.

[0043] The bounce-up detection sensor 28 is, for example, a reflection type optical sensor having a light emitting element and a light receiving element. The bounce-up detection sensor 28 emits light from the light emitting element toward the upper surface of the document G1 placed on the paper feed tray 44. The light emitted from the light emitting element is reflected by the document G1. When the reflected light is received by the light receiving element, the bounce-up detection sensor 28 outputs a detection signal having a signal level corresponding to the amount of received light to the control unit 2. The signal level is stronger as the distance between the bounce-up detection sensor 28 and the document G1 is shorter, and lower as this distance is longer.

[0044] In the present embodiment, when the surface of the document G1 approaches the bounce-up detection sensor 28 and the distance therebetween becomes less than a predetermined distance, the bounce-up detection sensor 28 outputs an ON signal (HIGH level signal) having a signal level equal to or higher than a predetermined threshold to the control unit 2. Further, when the surface of the document G1 is separated from the bounce-up detection sensor 28 by a predetermined distance or more, the bounce-up detection sensor 28 outputs an OFF signal (LOW level signal) having a signal level less than a predetermined threshold to the control unit 2.

[0045] During the feeding of the original document G, the control unit 2 determines whether the original document G1 has bounced up based on the signal level of the detection signal from the bounce-up detection sensor 28. Specifically, the control unit 2 acquires the detection signal immediately after the feeding of the original document G1 starts, and determines that the original document G1 has bounced up when the detection signal is the ON signal. When it is determined that the original document G1 has bounced up, the control unit 2 stops the feeding operation of the original document G1 by the paper feeding mechanism 31. This prevents damage to the original document G1 or G2, paper jams in the original document conveying device 120, and damage to each roller by the staples. Also, when the detection signal is the OFF signal, the control unit 2 determines that the original document G1 has not bounced up. In this case, the control unit 2 continues the feeding operation of the original document G1 by the paper feeding mechanism 31.

[0046] Further, when there is a foreign object on the upper surface of the uppermost original document G1 in the paper feeding tray 44, and the foreign object approaches the bounce-up detection sensor 28 and the distance therebetween becomes less than a predetermined distance, the bounce-up detection sensor 28 also outputs the ON signal (HIGH level signal) to the control unit 2. When there is no foreign object on the upper surface of the original document G1, the bounce-up detection sensor 28 outputs the OFF signal (LOW level signal) to the control unit 2.

[0047] Before feeding the original document G, while the paper feeding tray 44 is lifted from the initial position, the control unit 2 determines whether there is a foreign object on the upper surface of the original document G in the paper feeding tray 44 based on the signal level of the detection signal from the bounce-up detection sensor 28. Specifically, the control unit 2 acquires the detection signal while the paper feeding tray 44 is being lifted, and determines that there is a foreign object when the detection signal is the ON signal.

[0048] [Conveying mechanism 32] The conveying mechanism 32 further conveys the original document G sent out by the paper feeding mechanism 31 to the downstream side in the conveying direction. The conveying mechanism 32 includes a conveying path 61 formed in a U-shaped curve that extends from the paper feeding mechanism 31 through the opening 40A to the upper right of the opening 40A, and a plurality of conveying roller pairs 62 arranged along the conveying path 61.

[0049] The conveyance path 61 is mainly formed by plate-like members facing each other with a gap through which the original document G can pass. The opening 40A is provided in a region of the bottom portion 40 that faces the first carriage 81 (see FIG. 1) located at the home position. The opening 40A is a slit having the longitudinal direction in the front-rear direction. The opening 40A is an example of a reading position A where the scanner 110 reads the original document G. At the reading position A, an opening 61A corresponding to the opening 40A is provided in the plate-like member below the conveyance path 61, and the lower surface of the original document G being conveyed is exposed downward through the opening 40A and the opening 61A.

[0050] The pair of conveyance rollers 62 includes a driving roller 62D and a driven roller 62N. The shaft of each driving roller 62D is connected to a driving unit (not shown) including a motor and a reduction gear. When the motor of the driving unit is driven, the plurality of pairs of conveyance rollers 62 also rotate synchronously.

[0051] [Discharge mechanism 36] The discharge mechanism 36 further conveys the original document G that has been conveyed through the conveyance path 61 to the downstream side in the conveyance direction, and discharges the original document G to the paper discharge tray 43. The discharge mechanism 36 includes a discharge path 65 extending from near the downstream end of the conveyance path 61 in the conveyance direction to the paper discharge tray 43, a discharge guide portion 66 (an example of the discharge guide of the present invention) forming the discharge path 65, a pair of conveyance rollers 67 disposed at the upstream end of the discharge path 65 in the conveyance direction, and a pair of discharge rollers 68 disposed at the downstream end of the discharge path 65 in the conveyance direction.

[0052] The discharge guide portion 66 extends from the discharge port 69 opened at the downstream end of the discharge path 65 to the upstream side in the conveyance direction and reaches near the opening 61A.

[0053] The discharge path 65 is formed by the discharge guide portion 66 having a gap through which the original document G passes. The discharge guide portion 66 is composed of plate-like guide members 66A and 66B facing each other with the gap provided therebetween.

[0054] The conveying roller pair 67 is rotatably supported at the upstream end of the guide members 66A and 66B in the conveying direction. The discharge roller pair 68 is rotatably supported at the downstream end of the guide members 66A and 66B in the conveying direction. The conveying roller pair 67 includes a driving roller 67D supported by the upper guide member 66A and a driven roller 67N supported by the lower guide member 66B. The discharge roller pair 68 includes a driven roller 68N supported by the guide member 66A and a driving roller 68D supported by the guide member 66B. The driving rollers 67D and 68D are connected to a driving unit (not shown) including a motor and a reduction gear. A discharge port 69 through which the document G is discharged is formed in the contact area between the driving roller 68D and the driven roller 68N of the discharge roller pair 68.

[0055] [Second elevating mechanism 70] The second elevating mechanism 70 is a mechanism for elevating the discharge guide portion 66 in the vertical direction together with the discharge mechanism 36. The second elevating mechanism 70 includes a swing shaft 71, an eccentric cam 72, and a driving unit 73 (see FIG. 6). The swing shaft 71 is provided at the upstream end of the discharge path 65 in the conveying direction with the front-rear direction as the axial direction. In the present embodiment, the driving shaft of the conveying roller pair 67 also serves as the swing shaft 71, but the driven shaft of the conveying roller pair 67 may also serve as the swing shaft 71, or a swing shaft 71 different from the driving shaft and the driven shaft of the conveying roller pair 67 may be provided on the guide members 66A and 66B. The eccentric cam 72 is rotatable about a cam shaft 72A having the front-rear direction as the axial direction. The driving unit 73 is a driving source such as a motor. The cam shaft 72A is connected to the output shaft of the driving unit 73. The sliding surface of the eccentric cam 72 is in contact with the lower surface of the lower guide member 66B.

[0056] When a driving force in, for example, the forward rotation direction is input from the drive unit 73 to the camshaft 72A, the eccentric cam 72 rotates in the forward rotation direction in response to the driving force, and by this rotation operation, the eccentric cam 72 applies a force in the direction of pushing up the discharge mechanism 36. As a result, the discharge mechanism 36 swings in the vertical direction about the swing shaft 71. Along with this swinging operation, the position of the discharge port 69 moves upward. Also, when a driving force in, for example, the reverse rotation direction is input from the drive unit 73 to the camshaft 72A, the eccentric cam 72 rotates in the reverse rotation direction in response to the driving force, and by this rotation operation, the eccentric cam 72 rotates in the direction away from the discharge mechanism 36. As a result, the discharge mechanism 36 swings downward about the swing shaft 71 due to its own weight. Along with this swinging operation, the position of the discharge port 69 moves downward.

[0057] [Swing drive amount measurement unit 16] The swing drive amount measurement unit 16 (see FIG. 6) is a sensor that detects or measures the position of the discharge port 69 in the vertical direction and the amount of movement of the discharge port 69 in the vertical direction. The swing drive amount measurement unit 16 is provided in the second elevating mechanism 70. The swing drive amount measurement unit 16 is, for example, an optical rotary encoder and is provided on the camshaft 72A of the eccentric cam 72. The swing drive amount measurement unit 16 outputs a pulse signal indicating the rotation amount of the camshaft 72A. The control unit 2 (see FIG. 1) analyzes the pulse signal to obtain the rotation amount, and based on this rotation amount, calculates the position of the discharge port 69 in the vertical direction and the amount of movement of the discharge port 69 in the vertical direction. Note that the rotary encoder may be provided on the output shaft of the motor that drives the eccentric cam 72. Also, the swing drive amount measurement unit 16 may include an arithmetic unit that calculates the position of the discharge port 69 in the vertical direction and the amount of movement of the discharge port 69 in the vertical direction based on a pulse signal indicating the rotation amount of the camshaft 72A.

[0058] [Paper discharge original sensor 21] The paper discharge original document sensor 21 is a sensor for detecting the presence or absence of the original document G on the paper discharge tray 43 and its stacking amount. The paper discharge original document sensor 21 is provided at the right end of the upper guide member 66A. The paper discharge original document sensor 21 is, for example, a reflection type optical sensor having a light emitting element and a light receiving element, and emits light from the light emitting element in the right direction (toward the paper discharge tray 43). When the light emitted from the light emitting element is reflected from the side surface (left side surface) of the bundle of original documents G on the paper discharge tray 43, the light receiving element of the paper discharge original document sensor 21 receives the reflected light. The paper discharge original document sensor 21 outputs an electrical signal indicating the presence or absence of light reception in the light receiving element to the control unit 2. Specifically, when the light receiving element receives the reflected light, an ON signal (HIGH level signal) is output to the control unit 2, and when the light receiving element does not receive the reflected light, an OFF signal (LOW level signal) is output to the control unit 2. The control unit 2 determines the presence or absence of the original document G on the paper discharge tray 43 based on the signal level of the electrical signal. Further, the control unit 2 determines the stacking amount of the original document G on the paper discharge tray 43 based on the rising speed of the discharge guide unit 66 and the time from the start of the rise of the discharge guide unit 66 until the signal level changes from on to off.

[0059] By the way, in the original document conveyance device 120 capable of raising and lowering the paper feed tray 44, when there is a foreign object other than the original document G on the paper feed tray 44, when the paper feed tray 44 is raised, the foreign object may be pinched between the housing such as the cover portion 46 or the frame of the original document conveyance device 120, and the housing may be damaged. Also, in the process of conveying the original document G from the paper feed tray 44, the foreign object may enter the paper feed mechanism 31, the conveyance mechanism 32, the discharge mechanism 36, etc., and these mechanisms may be damaged. Further, when the foreign object enters the scanner 110 inside from the opening 40A or the opening 61A, the optical system device of the scanner 110 may be damaged.

[0060] In the document transport device 120 of the present embodiment, it is possible to easily and surely detect the presence or absence of the foreign matter in the paper feed tray 44 with a simple configuration. In particular, in the document transport device 120 having a function of detecting the bounce of the document G1, it is possible to detect the presence or absence of the foreign matter on the paper feed tray 44 without adding a sensor for detecting the foreign matter.

[0061] [Configuration of Control Unit 2] Referring to FIG. 6, the configuration of the control unit 2 and the lifting control executed by the control unit 2 will be described. As shown in FIG. 6, the control unit 2 is a microcomputer composed of a CPU 101, a ROM 102, a RAM 103, a storage unit 104, etc. The CPU 101 executes various processes by reading out control programs stored in storage devices such as the ROM 102 and the storage unit 104. The storage unit 104 is a non-volatile storage device such as a flash memory, and stores information and data (position information of the discharge guide unit 66, conveyance path length of the document G, conveyance speed of the document G, etc.) used for various processes. The control unit 2 may be realized by an IC such as an ASIC without using control programs or software.

[0062] The control unit 2 comprehensively controls the image forming apparatus 100. Hereinafter, the control unit 2 will be described as controlling the document transport device 120.

[0063] As shown in FIG. 6, the control unit 2 includes various processing units such as a first lifting processing unit 111 (an example of the lifting control unit of the present invention), a second lifting processing unit 112, a foreign matter determination unit 113 (an example of the first determination processing unit of the present invention), a bounce determination unit 114 (an example of the second determination processing unit of the present invention), and an output processing unit 115 (an example of the output processing unit of the present invention).

[0064] The control unit 2 functions as the various processing units by the CPU 101 executing various processes according to the control program.

[0065] The first lifting processing unit 111 controls the lifting of the paper feed tray 44 by driving the drive unit 93 of the first lifting mechanism 90.

[0066] The foreign object determination unit 113 determines whether there is a foreign object other than the original document G on the paper feed tray 44 before the original document G on the paper feed tray 44 is fed by the paper feed mechanism 31. That is, the foreign object determination unit 113 determines the presence or absence of the foreign object on the paper feed tray 44. The foreign object determined by the foreign object determination unit 113 is, for example, an object inadvertently placed on the upper surface of the original document G on the paper feed tray 44, an object temporarily placed on the original document G and left forgotten, or an item such as a possession of a user around the image forming apparatus 100 that has fallen and reached the paper feed tray 44. Various objects can be considered as specific examples of the foreign object. For example, it is an object having a certain size, such as stationery items like pens and clips, or ornaments such as glasses and wristwatches worn by the user. Note that the foreign object determination unit 113 can also determine an object that is not in contact with the original document G and is located above it. For example, if a user's hand or finger is present within the detection range of the bounce detection sensor 28 above the original document G, that hand or finger is also an example of the foreign object to be determined.

[0067] Specifically, while the paper feed tray 44 is being lifted from the initial position (the position shown in FIG. 3) by the first lifting processing unit 111, the foreign object determination unit 113 determines the presence or absence of the foreign object other than the original document G on the paper feed tray 44 based on the output signal of the bounce detection sensor 28. Specifically, when the detection signal from the bounce detection sensor 28 is the ON signal, or when the detection signal changes from the OFF signal to the ON signal, the foreign object determination unit 113 determines that there is a foreign object other than the original document G on the paper feed tray 44. In the present embodiment, while the paper feed tray 44 is being lifted, the foreign object determination unit 113 acquires the detection signal from the bounce detection sensor 28. When this detection signal is the ON signal, the foreign object determination unit 113 determines that there is a foreign object on the paper feed tray 44, and when the detection signal remains the OFF signal, the foreign object determination unit 113 determines that there is no foreign object on the paper feed tray 44.

[0068] When the foreign object determination unit 113 determines that there is a foreign object on the paper feed tray 44, the first lifting and lowering processing unit 111 stops the lifting of the paper feed tray 44.

[0069] In this case, the foreign object determination unit 113 may determine that there is a foreign object on the paper feed tray 44 when the ON signal continues for a predetermined first set time T1 after the detection signal of the bounce detection sensor 28 changes from the OFF signal to the ON signal.

[0070] Note that after the foreign object determination unit 113 determines that there is a foreign object on the paper feed tray 44, the first lifting and lowering processing unit 111 may resume the lifting of the paper feed tray 44 when the detection signal of the bounce detection sensor 28 returns to the original output value (OFF signal) within a predetermined second set time T2.

[0071] Based on the change in the detection signal of the bounce detection sensor 28 during the feeding of the document G by the paper feed mechanism 31, the bounce determination unit 114 determines that the fed document G is abnormal. Specifically, after the paper feed tray 44 is lifted to the initial position and the document G is fed by the paper feed mechanism 31, the bounce determination unit 114 acquires the detection signal from the bounce detection sensor 28 immediately after feeding. When this detection signal changes from the OFF signal to the ON signal, the bounce determination unit 114 determines that the fed document G is in a state of bouncing up (abnormal state). When the detection signal from the bounce detection sensor 28 remains the OFF signal, the bounce determination unit 114 determines that the document G is not in a state of bouncing up (normal state).

[0072] When the foreign object determination unit 113 determines that there is a foreign object on the paper feed tray 44, the output processing unit 115 outputs foreign object error information indicating that fact to the display operation unit of the image forming apparatus 100, an external output terminal, or the like. Also, when the bounce determination unit 114 determines that the document G fed from the paper feed tray 44 is abnormal, the output processing unit 115 outputs document abnormality error information indicating that fact to the display operation unit of the image forming apparatus 100, an external output terminal, or the like.

[0073] Based on the signal obtained from the paper discharge original document sensor 21, the second lifting and lowering processing unit 112 calculates the stacking amount of the original document G stacked on the paper discharge tray 43, and raises and lowers the discharge guide unit 66 according to the calculated stacking amount of the original document G.

[0074] In the present embodiment, by the second lifting and lowering processing unit 112, the discharge guide unit 66 is lifted and lowered between the lowest position P1 (the position shown in FIG. 3) and the dischargeable position P2 (the position shown in FIG. 5). Further, the second lifting and lowering processing unit 112 performs control to lower the discharge guide unit 66 to the lowest position P1 and wait at that position in a state where an execution signal for conveying the original document on the paper feed tray 44 is not input. Further, when a predetermined condition is satisfied, the second lifting and lowering processing unit 112 performs control to move the discharge guide unit 66 from the lowest position P1 to the dischargeable position P2 defined above its upper side. The position information of each of the above-mentioned positions P1 and P2 is stored, for example, in the storage unit 104 of the control unit 2.

[0075] Here, the lowest position P1 is an initial position where the discharge guide unit 66 is arranged before the conveyance of the original document G is executed. Specifically, it is a position where the position of the discharge port 69 is the lowest in the vertical movement range of the discharge guide unit 66. The lowest position P1 is a position where the original document G can be discharged to the paper discharge tray 43 without disturbing the original document G when the conveyance of the original document is executed in a state where no original document G is stacked on the paper discharge tray 43.

[0076] Also, the dischargeable position P2 is a position where the original document G can be discharged to the paper discharge tray 43, and is a position where the original document G can be appropriately discharged to the paper discharge tray 43 without being disturbed. The dischargeable position P2 is a position where the drop between the discharge port 69 and the upper surface of the original document G stacked on the paper discharge tray 43 becomes a predetermined specified value. For example, the discharge port 69 is at a position above the specified length (for example, 10 mm) of the height position of the upper surface of the original document G. In the present embodiment, the position of the discharge guide unit 66 when the output signal of the paper discharge original document sensor 21 changes from the ON signal to the OFF signal is the dischargeable position P2.

[0077] When the second lifting processing unit 112 detects a predetermined trigger signal, it determines the dischargeable position P2 of the discharge guide unit 66 according to the stacking amount of the document G on the paper discharge tray 43 (or the height position of the upper surface of the document G). Then, the second lifting processing unit 112 performs control to raise the discharge guide unit 66 from the lowest position P1 toward the dischargeable position P2. Then, when the discharge guide unit 66 reaches the dischargeable position P2, the second lifting processing unit 112 stops the raising of the discharge guide unit 66 and arranges the discharge guide unit 66 at the dischargeable position P2.

[0078] The trigger signal is, for example, a document detection signal that detects that the document G to be conveyed is placed on the paper feed tray 44, a setting input signal indicating that various settings (such as the setting of the reading surface, the setting of the number of printed copies, the image quality setting, etc.) are input to the image forming apparatus 100 or the display operation unit before the image reading process of the document G is performed on the image forming apparatus 100, an execution signal indicating that an image reading instruction or an image forming instruction of the document G is input to the image forming apparatus 100 or the display operation unit, and the like.

[0079] [Abnormality determination process (processing example 1)] Hereinafter, with reference to the flowchart of FIG. 7, an example of the procedure of the abnormality determination process executed by the control unit 2 will be described. In the flowcharts of each figure, steps S11, S12,... indicate the numbers of the processing procedures (steps). In the following description, it is assumed that the abnormality determination process is executed when the document G is conveyed to the document conveyance apparatus 120 in the image reading process of the document G. Also, hereinafter, it is assumed that the paper feed tray 44 is arranged at the initial position and the discharge guide unit 66 is arranged at the lowest position P1 before the conveyance of the document G. Also, in the following description, it is assumed that the document G is placed on the paper feed tray 44.

[0080] It should be noted that the execution order of each step in the abnormality determination process may be different as long as the same operational effects are produced.

[0081] Further, the control unit 2 includes not only the CPU 101, but also, for example, in the case of including a plurality of CPUs, the abnormality determination process may be executed with each step distributed by the plurality of CPUs.

[0082] Further, the present invention can be regarded as an invention of a method in which one or a plurality of steps included in the abnormality determination process are executed by the CPU 101 of the control unit 2 or another processor, and can also be regarded as a program for causing the CPU 101 of the control unit 2 or another processor to execute each step.

[0083] First, in step S11, the control unit 2 determines whether or not the document G is placed on the paper feed tray 44. For example, based on a document detection signal output from the document detection sensor 29 when the document G is placed on the paper feed tray 44, it is determined whether or not the document G is placed on the paper feed tray 44. When the document detection signal is the ON signal, the control unit 2 determines that the document G is placed on the paper feed tray 44. Note that the determination process in step S11 is for determining the start timing of the abnormality determination process. For example, as the start timing, it is also possible to use the setting input signal, the execution signal, or the like.

[0084] In the next step S12, when the control unit 2 acquires the ON signal from the document detection sensor 29, the control unit 2 raises the paper feed tray 44 from the initial position.

[0085] During the upward movement of the paper feed tray 44, the control unit 2 determines whether or not it has received the ON signal from the flip-up detection sensor 28 (S13). When the control unit 2 acquires the ON signal from the flip-up detection sensor 28 during the upward movement of the paper feed tray 44, the control unit 2 determines that there is a foreign object on the paper feed tray 44, and stops the upward movement of the paper feed tray 44 (S131). Then, the foreign object error information indicating that there is a foreign object on the paper feed tray 44 is output (S132), and a series of abnormality determination processes ends.

[0086] While the paper feed tray 44 is rising, if the control unit 2 continuously receives the OFF signal without receiving the ON signal from the bounce detection sensor 28, it determines that there is no foreign object on the paper feed tray 44 and continues to move the paper feed tray 44 upward.

[0087] When the paper feed tray 44 is raised to the paper feed position (S14), the control unit 2 stops moving the paper feed tray 44 upward. As a result, the document G on the paper feed tray 44 is in a state where it can be fed. In this state, the feeding of the document G by the paper feeding mechanism 31 is started (S16).

[0088] When the feeding of the document G is started, the control unit 2 determines whether it has received the ON signal from the bounce detection sensor 28 during the feeding of the document G (S17). If the control unit 2 obtains the ON signal from the bounce detection sensor 28 during the feeding of the document G, it determines that the rear end of the fed document G has bounced up, which is an abnormal state, and stops the feeding of the document G (S171). Then, it outputs the document abnormality error information indicating that the document G is in an abnormal state (S172), and a series of abnormal determination processes end.

[0089] If the control unit 2 does not obtain the ON signal from the bounce detection sensor 28 and continuously receives the OFF signal during the feeding of the document G, it determines that no abnormality has occurred in the document G and continues the feeding of the document G.

[0090] In the next step S18, it is determined whether the document G has been fed the predetermined specified number of sheets. The control unit 2 counts the number of times the document G is fed each time it is fed and stores the count value as the number of fed sheets. When the document G is fed the specified number of sheets, the upper surface of the document G on the paper feed tray 44 relatively drops accordingly. Therefore, when the document G is fed the specified number of sheets, the control unit 2 raises the paper feed tray 44 to the paper feed position (S181), and then repeats the processes after step S17.

[0091] Before the original document G is fed in the specified number of sheets, when all of the original document G on the paper feed tray 44 has been fed (S19), the control unit 2 returns the paper feed tray 44 to the initial position (S20), and a series of abnormality determination processes ends.

[0092] As described above, in the image forming apparatus 100 of the present embodiment, during the ascent of the paper feed tray 44, the control unit 2 determines whether or not the ON signal has been received from the flipping-up detection sensor 28 (S13). When the ON signal is received from the flipping-up detection sensor 28, it is determined that there is a foreign object on the paper feed tray 44, and then the upward movement of the paper feed tray 44 is stopped (S131). As a result, when the paper feed tray 44 is raised, it is possible to prevent the foreign object from being caught between the housing such as the cover portion 46 or the frame of the original document conveying device 120 and damaging the housing. Further, in the process of conveying the original document G from the paper feed tray 44, it is possible to prevent the foreign object from entering the paper feeding mechanism 31, the conveying mechanism 32, the discharging mechanism 36, and the like. Further, it is possible to prevent the foreign object from entering the scanner 110 inside from the opening 40A or the opening 61A.

[0093] Further, during the feeding of the original document G, when the control unit 2 acquires the ON signal from the flipping-up detection sensor 28, it is determined that the rear end of the fed original document G is in an abnormal state of flipping up, and the feeding of the original document G is stopped (S171). The reason why the rear end of the original document G flips up is mainly because the rear end of the original document G is stapled by a stapling tool such as the staple. Therefore, by quickly detecting the abnormal state of the original document G and stopping the feeding of the original document G, it is possible to prevent damage to the original document G, paper jams in the original document conveying device 120, and damage to each roller by the staple.

[0094] Further, the output signal of the flipping-up detection sensor 28 is used for the determination process of the presence or absence of a foreign object on the paper feed tray 44 and the determination process of the abnormal state of the original document G to be fed. That is, in each determination process, the flipping-up detection sensor 28 is used in common. For this reason, in the image forming apparatus 100 of the present embodiment, each determination process can be executed without providing an individual sensor for executing each determination process.

[0095] [Abnormality determination process (processing example 2)] As another embodiment of the present invention, the control unit 2 may execute an abnormality determination process according to the flowchart shown in FIG. 8. Note that the description of the same processes as those in the abnormality determination process shown in FIG. 7 is omitted.

[0096] For example, when the ON signal is acquired from the bounce detection sensor 28 during the ascent of the paper feed tray 44 in step S13 described above, immediately without stopping the ascent of the paper feed tray 44, it is determined whether the ON signal is continuously output for a predetermined first set time T1 (S130). When the ON signal is continuously output for the first set time T1, it may be determined that there is a foreign object in the paper feed tray 44. When the ON signal is continuously output for the first set time T1, the control unit 2 stops the upward movement of the paper feed tray 44 (S131).

[0097] [Abnormality determination process (processing example 3)] As still another embodiment of the present invention, the control unit 2 may execute an abnormality determination process according to the flowchart shown in FIG. 9. Note that the description of the same processes as those in the abnormality determination process shown in FIG. 7 is omitted.

[0098] For example, when the ON signal is acquired from the bounce detection sensor 28 during the ascent of the paper feed tray 44 in step S13 described above, the control unit 2 stops the ascent of the paper feed tray 44 (S131). Thereafter, before outputting the foreign object error information, the control unit 2 determines whether the detection signal of the bounce detection sensor 28 returns from the ON signal to the OFF signal within a predetermined second set time T2 (S1301). In step S1301, when the detection signal does not return from the ON signal to the OFF signal, the control unit 2 may determine that there is a foreign object in the paper feed tray 44. On the other hand, in step S1301, when the detection signal returns from the ON signal to the OFF signal, it is regarded as a false detection, and the control unit 2 determines that there is no foreign object in the paper feed tray 44, returns to step S12, and raises the paper feed tray 44 again.

[0099] [Supplementary Note of the Invention] The following is a supplementary note on the outline of the invention extracted from the above-described embodiments. Note that each configuration and each processing function described in the following supplementary note can be arbitrarily combined by making selections.

[0100] <Supplementary Note 1>[ A feeding tray on which sheets are loaded, A conveying mechanism that conveys the sheet along a conveyance path from the feeding tray to a discharge tray, A lifting mechanism including a driving unit that raises and lowers the feeding tray in the vertical direction, A lifting control unit that drives the driving unit to control the lifting of the feeding tray, A sensor that detects the upward bounce of the end portion on the downstream side in the feeding direction of the sheet fed from the feeding tray, A first determination processing unit that determines whether there is a foreign object other than the sheet on the feeding tray based on the output signal of the sensor before the sheet is fed by the conveying mechanism and while the feeding tray is rising by the lifting control unit, A sheet conveying device including a second determination processing unit that determines that the fed sheet is abnormal based on the change in the output signal of the sensor during the feeding of the sheet by the conveying mechanism.

[0101] <Supplementary Note 2>[ The sheet conveying device according to Supplementary Note 1, wherein the lifting control unit stops the lifting of the feeding tray when the first determination processing unit determines that there is the foreign object on the feeding tray.

[0102] <Supplementary Note 3>[ The sheet conveying device according to Supplementary Note 2, wherein the lifting control unit resumes the lifting of the feeding tray when the output value of the output signal of the sensor returns to the original output value within a predetermined first setting time after the first determination processing unit determines that there is the foreign object on the feeding tray.

[0103] <Supplementary Note 4>[ When the output value of the output signal continues for a second set time determined in advance after the output signal changes, the first determination processing unit determines that the foreign object is present on the feed tray. The sheet conveying device according to any one of Appendices 1 to 3.

[0104] <Appendix 5> When it is determined by the first determination processing unit that the foreign object is present on the feed tray, the sheet conveying device according to any one of Appendices 1 to 4 further includes an output processing unit that outputs error information indicating that fact.

[0105] <Appendix 6> The sheet conveying device according to any one of Appendices 1 to 5, An image processing device including an image processing unit that performs image processing on a sheet conveyed by the sheet conveying device.

Explanation of Signs

[0106] 1: Printer 2: Control unit 16: Swing drive amount measurement unit 21: Discharge original document sensor 28: Bounce detection sensor 29: Original document sensor 31: Paper feeding mechanism 32: Conveying mechanism 36: Discharge mechanism 43: Discharge tray 44: Feed tray 47: Cover frame 58: Holder detection sensor 59: Light shielding plate 61: Conveying path 65: Discharge path 66: Discharge guide part 66A: Guide member 66B: Guide member 68: Discharge roller pair 69: Discharge port 70: Second elevating mechanism 71: Swing shaft 72: Eccentric cam 90: First lifting mechanism 100: Image forming apparatus 101: CPU 102: ROM 103: RAM 104: Memory unit 111: First lifting processing unit 112: Second lifting processing unit 113: Foreign object determination unit 114: Bounce determination unit 115: Output processing unit 120: Original document conveying device

Claims

1. A feed tray on which a sheet is loaded, A conveying mechanism that conveys the sheet along a conveyance path from the feed tray to a discharge tray, A lifting mechanism including a drive unit that raises and lowers the feed tray in the vertical direction, A lift control unit that drives the drive unit to control the lifting of the feed tray, A sensor that detects the upward bounce of the end portion on the downstream side in the feeding direction of the sheet fed from the feed tray, A first determination processing unit that determines whether there is a foreign object other than the sheet on the feed tray based on the output signal of the sensor before the sheet is fed by the conveying mechanism and while the feed tray is rising by the lift control unit, A second determination processing unit that determines that the fed sheet is abnormal based on the change in the output signal of the sensor during the feeding of the sheet by the conveying mechanism. A sheet conveying device comprising:

2. The lift control unit stops the upward movement of the feed tray when the first determination processing unit determines that there is a foreign object on the feed tray. The sheet conveying device according to claim 1.

3. If the output value of the output signal of the sensor returns to the original output value within a predetermined first setting time after the first determination processing unit determines that there is a foreign object on the feed tray, the lift control unit resumes the upward movement of the feed tray. The sheet conveying device according to claim 2.

4. The first determination processing unit determines that there is a foreign object on the feed tray when the output value of the output signal continues for a predetermined second setting time after the output signal changes. The sheet conveying device according to claim 1 or 2.

5. The sheet conveying device according to claim 1 or 2, further comprising an output processing unit that outputs error information indicating that fact when the first determination processing unit determines that there is a foreign object on the feed tray.

6. The sheet conveying device according to claim 1, An image processing apparatus comprising: an image processing unit that performs image processing on a sheet conveyed by the sheet conveying device.

Images