Document feeding device

Abstract

The invention provides a document conveying device, comprising a lifting plate, a pickup roller, a lifting motor, a delay roller and a control unit. In a manual mode, the control unit rotates the delay roller in a direction of conveying the document in the conveying direction of the document. In addition, after the rotation of the pickup roller starts, the control unit causes the lifting motor to start lowering the lifting plate while the pickup roller conveys the document.

Description

Technical Field

[0001] The present invention relates to a document conveying device for feeding and conveying a placed document. Background Art

[0002] There is an image reading device (e.g., a multifunction machine) equipped with a document feeding device. The document feeding device feeds the placed documents one by one. Image data is generated by reading the fed documents. In the document feeding device, multiple documents are sometimes fed and fed in an overlapping manner. If there is a situation where most of the documents are fed in an overlapping manner, there is also a situation where the front document and a part of the subsequent document are fed in an overlapping manner. In order to eliminate overlap, a separation mechanism is sometimes provided. The separation mechanism includes, for example, a separation roller. The separation roller rotates in the direction in which the document is fed in the opposite direction (upstream direction) to the feeding direction. The separation roller separates the documents that are fed in an overlapping manner and feeds back the unnecessary documents. The separation roller helps to eliminate overlapping feeding.

[0003] There are manuscripts made of multiple overlapping sheets. Such manuscripts include, for example, receipts for goods delivery (home delivery). In most delivery receipts, carbon paper for copying is overlapped. In addition, there are manuscripts with peelable sheets (for example, labels, seals) attached to them, and manuscripts with photos attached to them. In such manuscripts, if the separation roller is rotated in the direction opposite to the conveying direction, sheets that are attached to the manuscript and are not intended to be peeled off may be peeled off. If the separation roller is made to perform an action to eliminate overlapping conveying, the manuscript may be damaged.

[0004] Therefore, sometimes the document conveying device can use a mode (e.g., non-separation mode) in which the separation roller does not perform separation action. In the non-separation mode, the separation roller rotates in the direction in which the document is conveyed in the conveying direction. That is, the rotation direction of the separation roller in the non-separation mode is opposite to that in the separation mode.

[0005] However, in the non-separation mode, the function of eliminating the overlapping of originals does not work. In the case where multiple originals are placed, in the non-separation mode, there is a problem that the originals are easily fed and transported in a state of overlapping or in a state of being connected. In other words, in the non-separation mode, there is a problem that the paper is easily fed together. Summary of the invention

[0006] The present invention has been made in view of the above-mentioned problems of the prior art, and can avoid joint feeding (overlapping feeding) even if a plurality of originals are placed in a manual mode in which the retard roller is rotated in the direction in which the original is fed.

[0007] In order to solve the above-mentioned problems, the document feeding device of technical solution 1 includes a lifting plate, a pickup roller, a lifting motor, a delay roller and a control unit. The document is placed on the lifting plate. The pickup roller contacts the topmost document among the documents placed on the lifting plate. The pickup roller rotates to transport the document in the transport direction of the document. The lifting motor raises and lowers the lifting plate. When the document feeding starts, the lifting motor raises the lifting plate until the topmost document contacts the pickup roller. The delay roller is arranged at a position downstream of the transport direction than the pickup roller. The delay roller contacts the document fed by the pickup roller. When the normal mode is selected, the control unit rotates the delay roller in a direction to transport the document in the opposite direction to the transport direction. When the manual mode is selected, the control unit rotates the delay roller in a direction to transport the document in the transport direction. When the manual mode is selected, the control unit controls the lift motor to start lowering the lift plate after the pickup roller starts rotating and while the pickup roller is conveying the document.

[0008] According to the present invention, in the manual mode for rotating the retard roller in the direction for conveying the document in the conveying direction, even if a plurality of documents are set, occurrence of joint feeding can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a diagram showing an example of a multifunction peripheral according to the embodiment.

[0010] Figure 2 It is a diagram showing an example of a document feeding device and an image reading unit according to the embodiment.

[0011] Figure 3 It is a diagram showing an example of a document feeding device and an image reading unit according to the embodiment.

[0012] Figure 4 An example of a diagram showing the interior of the document feeding device according to the embodiment as viewed from above is shown.

[0013] Figure 5 This is a diagram showing an example of transmission of drive of a paper feed motor according to the embodiment.

[0014] Figure 6 This is a diagram showing an example of transmission of drive of a paper feed motor according to the embodiment.

[0015] Figure 7 This is a diagram showing an example of the flow of conveyance reading in the normal mode according to the embodiment.

[0016] Figure 8This is a diagram showing an example of the flow of conveyance reading in the single-sheet reading mode according to the embodiment.

[0017] Fig. 9 This is a diagram showing an example of the flow of transport reading in the continuous reading mode according to the embodiment.

[0018] Fig.10 This is a timing chart showing an example of the operation in the manual mode according to the embodiment.

[0019] Fig.11 It is a diagram showing an example of a mode selection screen according to the embodiment.

[0020] Fig.12 This is a diagram showing an example of a flow of automatically changing from the continuous reading mode to the single-sheet reading mode according to the embodiment.

[0021] Fig.13 This is a diagram showing an example of a flow of automatic switching from the single-sheet reading mode to the continuous reading mode according to the embodiment.

[0022] Fig.14 This is a diagram showing an example of the operation when the automatic mode change is not permitted. DETAILED DESCRIPTION

[0023] Below, use Figure 1 to Figure 14 An example of the document conveying device 1 according to the embodiment will be described. In the following description, a multifunction machine 100 including the document conveying device 1 is described as an example. However, the components such as the configuration and arrangement described in each embodiment are not intended to limit the scope of protection but are merely illustrative examples.

[0024] (Multifunctional machine 100)

[0025] based on Figure 1 An example of the multifunction peripheral 100 according to the embodiment will be described. Figure 1 It is a diagram showing an example of the multifunction peripheral 100 according to the embodiment.

[0026] like Figure 1 As shown, the multifunction peripheral 100 includes a main control unit 2 , a storage unit 3 , an image reading device 4 , an operation panel 5 , and a printing unit 6 in addition to the document feeding device 1 .

[0027] The main control unit 2 controls the operation of the multifunction machine 100. The main control unit 2 controls the operation of each unit of the multifunction machine 100 in a job such as copying or sending. The main control unit 2 is a substrate including a control circuit 20, an image data generation circuit 21, an image processing circuit 22, and a communication unit 23. The control circuit 20 is, for example, a CPU. The control circuit 20 performs processing and calculation related to the job.

[0028] The image data generation circuit 21 generates read image data based on the analog image signal output by the image reading device 4 when the original is read. The image data generation circuit 21 is a circuit that processes the analog image signal, and includes, for example, an amplifier circuit, a compensation circuit, and an A / D conversion circuit. The A / D conversion circuit converts the analog image signal adjusted by the amplifier circuit and the compensation circuit into digital data (image data). The image processing circuit 22 performs image processing. The image processing circuit 22 processes the read image data and generates image data for printing or sending. The image processing circuit 22 is, for example, an ASIC (an integrated circuit designed and developed for image processing).

[0029] The communication unit 23 includes a communication circuit and a communication memory. The communication unit 23 communicates with the computer 200 and the facsimile device 300. The computer 200 is, for example, a PC or a server. The operation panel 5 receives the setting of the destination. The main control unit 2 causes the communication unit 23 to send the image data obtained by reading the original to the set destination (scanning and sending, fax sending). In addition, the communication unit 23 receives the printing data from the computer 200 and the facsimile device 300. The main control unit 2 causes the printing unit 6 to print (printing job, fax receiving and printing) based on the received printing data.

[0030] The storage unit 3 includes various storage devices. The storage unit 3 includes, for example, a RAM 31 , a ROM 32 , and a memory 33 (HDD or SSD) as storage devices. The main control unit 2 controls each unit based on the program and data in the storage unit 3 .

[0031] The operation panel 5 accepts settings made by the user. The operation panel 5 includes a display panel 51, a touch panel 52, and hard keys 53. The main control unit 2 causes the display panel 51 to display messages and setting screens. In addition, the main control unit 2 causes the display panel 51 to display operation images. Operation images are, for example, buttons, keys, and labels. The main control unit 2 recognizes the operation image being operated based on the output of the touch panel 52. The hard keys 53 include a start key and numeric keys. The touch panel 52 and the hard keys 53 accept setting operations (operations related to the job) made by the user. For example, the operation panel 5 accepts the selection of a reading mode for a document. The main control unit 2 recognizes the setting content based on the output of the operation panel 5.

[0032] The printing section 6 includes a paper supply section 61, a paper conveying section 62, an image forming section 63, and a fixing section 64. The paper supply section 61 includes a paper supply box and a pickup roller. The paper supply box stores paper. The pickup roller delivers paper. During the printing operation, the main control section 2 causes the paper supply section 61 to feed paper. The paper conveying section 62 includes a paper conveying roller pair for conveying paper and a paper conveying motor. The paper conveying roller pair conveys paper. The paper conveying motor rotates the paper conveying roller pair. The main control section 2 causes the paper conveying section 62 to convey paper.

[0033] The image forming unit 63 includes, for example, a photosensitive drum, a charging device, an exposure device, a developing device, and a transfer roller. The main control unit 2 causes the image forming unit 63 to form a toner image based on the image data. The main control unit 2 causes the image forming unit 63 to transfer the toner image to the conveyed paper. The fixing unit 64 includes a heater, a fixing rotating body, and a fixing motor. The heater heats the fixing rotating body. The paper is conveyed while contacting the fixing rotating body. As a result, the toner image is fixed to the paper. The main control unit 2 causes the fixing unit 64 to fix the transferred toner image to the paper. The paper conveying unit 62 discharges the printed paper to the outside of the machine.

[0034] (Document feeding device 1, image reading device 4)

[0035] Next, based on Figure 2-3 The document feeding device 1 and the image reading device 4 according to the embodiment will be described. Figure 2 , Figure 3 FIG. 1 is a diagram showing an example of the document feeding device 1 and the image reading unit according to the embodiment.

[0036] The image reading device 4 includes a contact glass 41 for conveyance reading and a document table 42 (contact glass for stage reading). The contact glass 41 for conveyance reading and the document table 42 are arranged on the upper surface of the image reading device 4. When conveyance reading is performed, the user places one or more documents on the lifting plate 8 (document tray 11). When the document is placed on the document conveying device 1 (lifting plate 8), the main control unit 2 causes the image reading device 4 to perform conveyance reading. Conveyance reading is the reading of the document conveyed by the document conveying device 1.

[0037] When the document is not placed on the lift plate 8 (document tray 11), the main control unit 2 causes the image reading device 4 to perform stage reading. Stage reading is the reading of the document placed on the document table 42. When performing stage reading, the user places the document on one side (upper side) of the document table 42.

[0038] The image reading device 4 includes a carriage 43, a moving belt 44, a first reading pulley 45, a second reading pulley 46, and a carriage motor 47 (see Figure 3The carriage 43 is a CIS scanning unit. The image reading device 4 may include a CCD reading unit.

[0039] The moving belt 44 is an endless belt. The moving belt 44 is wound around each pulley. The moving belt 44 is connected to the carriage 43. When the carriage 43 is moved, the main control unit 2 rotates the carriage motor 47. The carriage motor 47 rotates the first reading pulley 45 or the second reading pulley 46. As a result, the moving belt 44 moves in a circular motion. The carriage motor 47 can rotate forward and reverse. In conjunction with the circular motion of the moving belt 44, the carriage 43 moves in the horizontal direction (sub-scanning direction, direction perpendicular to the main scanning direction, Figure 2 The slide 43 moves on the other side (lower side) of each contact glass.

[0040] The carriage 43 includes a light source 48, a lens, and an image sensor 49 (see Figure 3 ). When reading the manuscript, the main control unit 2 turns on the light source 48. The light source 48 irradiates light to the manuscript through the contact glass 41 for conveying and reading or the manuscript table 42. The light source 48 is, for example, an LED. The lens guides the reflected light of the manuscript to each light receiving element of the image sensor 49. The image sensor 49 reads the manuscript placed on the manuscript table 42 or the manuscript conveyed on the contact glass 41 for conveying and reading. The image sensor 49 is a line sensor. The image sensor 49 includes a plurality of light receiving elements (photoelectric conversion elements, pixels).

[0041] The light receiving element receives light reflected by the document. Each light receiving element outputs an analog image signal corresponding to the amount of received light (amount of reflected light). The analog image signal is input to the main control unit 2. The image data generation circuit 21 of the main control unit 2 generates read image data based on the input analog image signal.

[0042] During transport reading, the main control unit 2 moves the carriage 43 (the position of the reading line of the image sensor 49) below the transport reading contact glass 41. The carriage 43 reads the original document passing over the transport reading contact glass 41. During stage reading, the main control unit 2 moves the carriage 43 at a predetermined speed along the sub-scanning direction below the original table 42. During the movement, the carriage 43 reads the original document placed on the original table 42.

[0043] The document transport device 1 is provided above the image reading device 4. The document transport device 1 transports the placed document toward the reading position (contact glass 41 for transport reading). The document transport device 1 transports the document one by one. Figure 2 The document feeding device 1 is opened and closed in the vertical direction as a fulcrum on the back side of the paper surface. The document feeding device 1 functions as a cover for pressing each contact glass of the image reading device 4 from above.

[0044] like Figure 2 As shown, the document conveying device 1 includes, from the upstream side in the document conveying direction, a document tray 11, a pickup roller 12, a separation conveying unit 7, a registration roller pair 13, a plurality of conveying rollers 14a, 14b, 14c, a discharge roller pair 14d, and a document discharge tray 15.

[0045] The document tray 11 is a portion where the document is placed. The pickup roller 12 (equivalent to the paper feeding rotating body), the rotating body included in the separation and conveying section 7, the registration roller pair 13, the plurality of conveying rollers 14a, 14b, 14c, and the discharge roller pair 14d are rotating bodies for conveying the document. The delivered document is finally discharged to the document discharge tray 15.

[0046] like Figure 3 As shown in FIG. 1 , the document transport device 1 includes a transport control unit 10 (equivalent to a control unit), a document placement sensor 16, a paper feed motor 17, a document transport motor 18, a lift motor 81, and an upper limit detection sensor 82. The paper feed motor 17 and the document transport motor 18 are motors for rotating a rotating body for transporting a document. For example, a stepping motor can be used for the paper feed motor 17, the document transport motor 18, and the lift motor 81.

[0047] The conveying control unit 10 and the main control unit 2 are connected by a signal line and can communicate. The conveying control unit 10 is, for example, a substrate. For example, the conveying control unit 10 includes a conveying control circuit 10a (CPU), a memory 10b (RAM, ROM), and a motor control circuit 10c. The motor control circuit 10c is, for example, a motor driver IC. The motor control circuit 10c controls the rotation, stop, and rotation speed of each motor in the document conveying device 1.

[0048] The document tray 11 is provided with a pair of limiting cursors 11a for limiting the document. The pair of limiting cursors 11a can move in a direction perpendicular to the document conveying direction. The pair of limiting cursors 11a are linked. The pair of limiting cursors 11a are slid to clamp the document. Thus, the position of the document is not deviated.

[0049] The downstream side portion of the document tray 11 in the conveying direction serves as a lift plate 8. The lift plate 8 is a part of the document tray 11. Placing a document on the document tray 11 also means placing the document on the lift plate 8.

[0050] A document placement sensor 16 is provided on the lifting plate 8 in the document tray 11. The document placement sensor 16 is, for example, a light sensor. The output level of the document placement sensor 16 is different when a document is placed and when a document is not placed. The output of the document placement sensor 16 is input to the conveying control unit 10 (conveyance control circuit 10a) described later. The conveying control unit 10 (conveyance control circuit 10a) identifies whether there is a document placed on the document tray 11 (lifting plate 8). When it is identified that a document is placed, the conveying control unit 10 notifies the main control unit 2 of this fact. In addition, when it is identified that the document disappears from the document tray 11, the conveying control unit 10 also notifies the main control unit 2 of this fact.

[0051] When reading a document placed on the document tray 11 (when conveying and reading), the main control unit 2 issues a document conveying instruction to the conveying control unit 10. The conveying control unit 10 controls the operation of the document conveying device 1 based on the instruction.

[0052] A rotating shaft 80 is provided at the upstream end of the lifting plate 8 in the document conveying direction. The document conveying device 1 includes a lifting motor 81. The lifting motor 81 is a motor for raising and lowering the lifting plate 8. The lifting motor 81 rotates the rotating shaft 80. According to the rotation of the lifting motor 81, the downstream end of the lifting plate 8 in the document conveying direction rises or falls. Alternatively, a lifting component may be provided below the lifting plate 8. The lifting component includes a shaft and a lifting plate mounted on the shaft. The shaft is supported so as to be rotatable. The axial direction of the shaft is a direction perpendicular to the document conveying direction. The lifting motor 81 can rotate the shaft. If the lifting motor 81 is rotated to one side, the shaft rotates in the direction in which the lifting plate lifts the lifting plate 8 from the bottom to the top. If the lifting motor 81 is rotated to the other side, the shaft rotates in the direction in which the lifting plate lowers the lifting plate 8. In this way, the lifting component can be used to raise and lower the lifting plate 8.

[0053] The upper limit detection sensor 82 is a sensor for detecting that the lifting plate 8 has risen to the upper limit position. The pickup roller 12 is arranged above the lifting plate 8. The pickup roller 12 can swing in the up-down direction. A support member 12b is provided to support the pickup roller 12 so as to be able to swing. For example, the support member 12b is hooked on the rotating shaft of the second paper feed roller 72.

[0054] The upper limit detection sensor 82 is, for example, a transmission-type optical sensor. If the lifting plate 8 rises, the placed original document contacts the pickup roller 12. In addition, if the lifting plate 8 continues to rise, the original document is lifted together with the pickup roller 12. If the pickup roller 12 is lifted to the upper limit, the protrusion provided on the support member 12b blocks the light path of the upper limit detection sensor 82. The output level of the upper limit detection sensor 82 changes when the lifting plate 8 (pickup roller 12) is located at the upper limit position and when it is not located at the upper limit position. The output of the upper limit detection sensor 82 is input to the conveying control unit 10. The conveying control unit 10 identifies whether the lifting plate 8 (pickup roller 12) is located at the upper limit position based on the output of the upper limit detection sensor 82.

[0055] The separation conveying section 7 includes a first paper feed roller 71, a second paper feed roller 72, a paper feed belt 73, and a delay roller 70. The paper feed belt 73 is wound around the first paper feed roller 71 and the second paper feed roller 72. The conveying control section 10 rotates the paper feed motor 17. As a result, the first paper feed roller 71 rotates, and the paper feed belt 73 moves in a circular motion. The paper feed belt 73 conveys the original document conveyed from the pickup roller 12 to the downstream side in the conveying direction.

[0056] When the paper feed motor 17 is a stepping motor, the conveyance control unit 10 inputs pulses to the paper feed motor 17. The rotation angle of the paper feed motor 17 for each pulse is determined. Therefore, for each pulse, the pickup roller 12 feeds the document by a predetermined amount. For each pulse, the first paper feed roller 71, the second paper feed roller 72, and the paper feed belt 73 feed the document by a predetermined amount.

[0057] The retard roller 70 is provided below the paper feed belt 73. The retard roller 70 is in contact with the paper feed belt 73. The paper feed motor 17 also rotates the retard roller 70. The rotation direction of the retard roller 70 differs depending on the mode (details will be described later).

[0058] A registration roller pair 13, conveying rollers 14a, 14b, 14c, and a discharge roller pair 14d are provided along the document conveying path 110. These roller pairs convey the document. The document is finally discharged to the document discharge tray 15. The document conveying motor 18 rotates the registration roller pair 13, conveying rollers 14a, 14b, 14c, and discharge roller pair 14d. When the document is conveyed, the conveying control unit 10 rotates the document conveying motor 18.

[0059] The registration roller pair 13 is provided on the downstream side of the paper feeding belt 73 in the document conveying direction. A feed sensor 19 is provided between the paper feeding belt 73 (the first paper feeding roller 71, the retard roller 70, and the pickup roller 12) and the registration roller pair 13. The feed sensor 19 is, for example, a light sensor. The output level of the feed sensor 19 is different when the document is detected and when the document is not detected.

[0060] The output of the feed sensor 19 is input to the conveyance control unit 10. Based on the output of the feed sensor 19, the conveyance control unit 10 recognizes that the leading edge of the document has reached the feed sensor 19 (the placement position of the feed sensor 19, the detection area of ​​the feed sensor 19), is passing through, or has passed through the feed sensor 19.

[0061] The conveying control unit 10 can control the rotation of the registration roller pair 13 based on the output of the feed sensor 19. For example, the conveying control unit 10 stops the registration roller pair 13 from the time when the front end of the document is recognized to have reached the feed sensor 19 until the predetermined deflection production time has passed. The front end of the document collides with the registration roller pair 13 in the stopped state. The conveying control unit 10 continues the conveying based on the first paper feed roller 71 (paper feed belt 73) and the pickup roller 12 while maintaining the stopped state of the registration roller pair 13. As a result, the document is deflected. Due to the elasticity of the deflected document, the front end of the document is along the roller gap of the registration roller pair 13. As a result, the inclination of the document is improved.

[0062] In addition, an overlapped feed detection sensor 111 is provided near the downstream side of the registration roller pair 13 in the document conveying direction (between the registration roller pair 13 and the conveying roller 14a). The overlapped feed detection sensor 111 is, for example, an ultrasonic sensor. The overlapped feed detection sensor 111 includes a transmitting unit and a receiving unit. The transmitting unit and the receiving unit are arranged to sandwich the conveyed document in the up-down direction. The transmitting unit emits ultrasonic waves when the document is conveyed. When overlapped feed occurs, the level of ultrasonic waves received by the receiving unit is lower than when only one document is conveyed. The output of the receiving unit is input to the conveying control unit 10. The conveying control unit 10 can determine whether overlapped feed has occurred based on the size of the output of the receiving unit.

[0063] The registration roller pair 13, the conveying rollers 14a, 14b, 14c, and the discharge roller pair 14d convey the document along the document conveying path 110. The document is finally discharged to the document discharge tray 15. The document conveying motor 18 rotates the conveying rollers 14a, 14b, 14c and the discharge roller pair 14d. When the document is conveyed, the conveying control unit 10 rotates the document conveying motor 18.

[0064] (Drive of each roller)

[0065] Next, based on Figures 4 to 6 An example of driving each roller in the document feeding device 1 according to the embodiment will be described. Figure 4 An example of a diagram showing the interior of the document feeding device 1 according to the embodiment as viewed from above is shown. Figure 5 , Figure 6 This is a diagram showing an example of transmission of drive of the paper feed motor 17 according to the embodiment.

[0066] Figure 4The arrow D in FIG. 1 indicates the conveying direction of the original document. Figure 4 As shown in FIG. 1 , the portion of the pickup roller 12 that contacts the document and the paper feed belt 73 are located approximately in the center in a direction perpendicular to the document transport device 1. Figure 4 In the drawing, the portion of the pickup roller 12 that contacts the document and the paper feed belt 73 are hardly visible due to the cover 74. Figure 4 In the embodiment, the first paper feed roller 71 includes a rotation shaft 71 a extending in a direction perpendicular to the conveying direction. The rotation shaft 71 a is rotatably supported. The paper feed motor 17 rotates the rotation shaft 71 a.

[0067] In addition, the first pulley 71p is mounted on the rotating shaft 71a. The second pulley 12p is mounted on the pickup roller 12. The interlocking belt 75 is stretched between the above pulleys. When the rotating shaft 71a (first paper feed roller 71) rotates, the interlocking belt 75 rotates. The pickup roller 12 also rotates in conjunction.

[0068] In the document conveying device 1, the paper feed motor 17 rotates the pickup roller 12, the first paper feed roller 71, the second paper feed roller 72, the paper feed belt 73, and the delay roller 70. The paper feed motor 17 can rotate in two directions, namely, the first direction (positive direction) and the second direction (reverse direction). In order to rotate the pickup roller 12, the first paper feed roller 71, the second paper feed roller 72, the paper feed belt 73, and the delay roller 70, the document conveying device 1 includes a drive mechanism 9.

[0069] The driving mechanism 9 includes a first driving mechanism 9a, a second driving mechanism 9b, and a third driving mechanism 9c. The first driving mechanism 9a, the second driving mechanism 9b, and the third driving mechanism 9c transmit the drive of the paper feed motor 17.

[0070] Figure 5 , Figure 6 is a diagram showing an example of gears included in each drive mechanism 9. Figure 5 , Figure 6 In the figure, the rectangle in the upper left corner represents the paper feed motor 17. A motor gear is mounted on the rotating shaft 17a of the paper feed motor 17. A transmission belt 90a is provided between the end of the base gear 90 and the motor gear. If the motor gear (paper feed motor 17) rotates, the base gear 90 rotates. Figure 5 , Figure 6 In the figure, the basic gear 90 is shown larger for convenience. The basic gear 90 is connected to a first drive mechanism 9a, a second drive mechanism 9b, and a third drive mechanism 9c.

[0071] Specifically, the first drive mechanism 9a is a mechanism for rotating the first paper feed roller 71 and the pickup roller 12. The first drive mechanism 9a includes a first gear 91. The first gear 91 is mounted on the rotating shaft 71a of the first paper feed roller 71. The first gear 91 meshes with the base gear 90. Therefore, if the paper feed motor 17 rotates, the first drive mechanism 9a rotates the first paper feed roller 71.

[0072] As described above, the first pulley 71p is provided on the rotation shaft 71a of the first paper feed roller 71. The second pulley 12p is provided on the rotation shaft 12a of the pickup roller 12. The pickup roller 12 rotates in conjunction with the first paper feed roller 71 by the interlocking belt 75 wound around the first pulley 71p and the second pulley 12p.

[0073] In addition, the second drive mechanism 9b is also a mechanism for rotating the first paper feed roller 71 and the pickup roller 12. The second drive mechanism 9b includes a second gear 92 and a third gear 93. The second gear 92 meshes with the base gear 90. The third gear 93 meshes with the second gear 92. The third gear 93 is mounted on the rotating shaft 71a of the first paper feed roller 71. If the paper feed motor 17 rotates, the second drive mechanism 9b rotates the first paper feed roller 71.

[0074] In addition, the third driving mechanism 9c is a mechanism for rotating the delay roller 70. The third driving mechanism 9c includes a fourth gear 94, a fifth gear 95, and a sixth gear 96. The base gear 90 meshes with the fourth gear 94. The fourth gear 94 meshes with the fifth gear 95. The fifth gear 95 meshes with the sixth gear 96. The sixth gear 96 is attached to the rotating shaft 70a of the delay roller 70. If the paper feed motor 17 rotates, the third driving mechanism 9c rotates the delay roller 70.

[0075] The first drive mechanism 9a and the second drive mechanism 9b are mechanisms for rotating the first paper feed roller 71 and the pickup roller 12 in the direction of conveying the document. The third drive mechanism 9c is a mechanism for switching the rotation direction of the retard roller 70 in accordance with the rotation direction of the paper feed motor 17.

[0076] 1. When the paper feed motor 17 is rotated in the positive direction

[0077] based on Figure 5 An example of driving transmission when the paper feed motor 17 is rotated in the first direction (positive direction) will be described. Figure 5 Center, left indicates the feeding direction of the original. Figure 5 The lower side corresponds to the front side of the document feeding device 1 , and the upper side corresponds to the back side of the document feeding device 1 .

[0078] exist Figure 5In the example of , the counterclockwise direction (CCW) is the first direction. When the paper feed motor 17 is rotated in the first direction, the base gear 90 also rotates in the counterclockwise direction (CCW).

[0079] If the basic gear 90 rotates in the counterclockwise direction (CCW), the first gear 91 of the first driving mechanism 9a rotates in the clockwise direction (CW). As a result, both the first paper feed roller 71 and the pickup roller 12 rotate in the clockwise direction (CW). The clockwise direction is the direction in which the first paper feed roller 71, the second paper feed roller 72, the paper feed belt 73, and the pickup roller 12 rotate in a manner to transport the document downstream in the transport direction. In this case, the first gear 91 rotates the rotating shaft 71a of the first paper feed roller 71 in the clockwise direction (CW).

[0080] If the base gear 90 rotates in the counterclockwise direction (CCW), the second gear 92 of the second drive mechanism 9b rotates in the clockwise direction (CW). The third gear 93 of the second drive mechanism 9b meshing therewith rotates in the counterclockwise direction (CCW). The third gear 93 is intended to rotate the rotating shaft 71a of the first paper feed roller 71 in the counterclockwise direction (CCW).

[0081] Here, the third gear 93 has a first one-way clutch 97 built therein. The first one-way clutch 97 does not transmit torque when the third gear 93 intends to rotate in the counterclockwise direction (CCW). When the paper feed motor 17 is rotated in the first direction (positive direction), the transmission of the driving force in the second drive mechanism 9b is cut off by the first one-way clutch 97.

[0082] If the base gear 90 rotates in the counterclockwise direction (CCW), the fourth gear 94 of the third drive mechanism 9c rotates in the clockwise direction (CW). The fifth gear 95 of the third drive mechanism 9c meshing with the fourth gear 94 rotates in the counterclockwise direction (CCW). The sixth gear 96 of the third drive mechanism 9c meshing with the fifth gear 95 rotates in the clockwise direction (CW). The sixth gear 96 rotates the rotating shaft 70a of the delay roller 70 in the clockwise direction (CW).

[0083] The retard roller 70 and the paper feed belt 73 face each other (see Figure 2 ). Therefore, in this case, the delay roller 70 rotates in a manner to feed the document in the direction opposite to the conveying direction of the document (upstream side). That is, when the paper feed motor 17 is rotated in the first direction, the third drive mechanism 9c rotates the delay roller 70 in the direction of conveying the document upstream.

[0084] 2. When the paper feed motor 17 is rotated in the opposite direction

[0085] based on Figure 6An example of driving transmission when the paper feed motor 17 is rotated in the second direction (reverse direction) will be described. Figure 6 In the figure, the left direction indicates the feeding direction of the original. Figure 6 The lower side corresponds to the front side of the document feeding device 1 , and the upper side corresponds to the back side of the document feeding device 1 .

[0086] exist Figure 6 In the example of , the clockwise direction (CW) is the second direction. If the paper feed motor 17 is rotated in the second direction, the basic gear 90 also rotates in the clockwise direction (CW). If the basic gear 90 rotates in the clockwise direction (CW), the first gear 91 of the first driving mechanism 9a rotates in the counterclockwise direction (CCW). The first gear 91 is intended to rotate the rotating shaft 71a of the first paper feed roller 71 in the counterclockwise direction (CCW).

[0087] Here, the first gear 91 has a second one-way clutch 98 built in. The second one-way clutch 98 does not transmit torque when the first gear 91 (rotating shaft 71a of the first paper feed roller 71) is intended to rotate in the counterclockwise direction (CCW). When the paper feed motor 17 is rotated in the second direction (opposite direction), the transmission of the driving force in the first drive mechanism 9a is cut off by the second one-way clutch 98.

[0088] If the basic gear 90 rotates in the clockwise direction (CW), the second gear 92 of the second drive mechanism 9b rotates in the counterclockwise direction (CCW). The third gear 93 of the second drive mechanism 9b meshing therewith rotates in the clockwise direction (CW). The third gear 93 intends to rotate the rotating shaft 71a of the first paper feed roller 71 in the clockwise direction (CW). In this case, the first one-way clutch 97 of the third gear 93 transmits torque. When the paper feed motor 17 is rotated in the second direction (opposite direction), the third gear 93 of the second drive mechanism 9b rotates the rotating shaft 71a of the first paper feed roller 71 in the clockwise direction (CW).

[0089] As a result, the first paper feed roller 71 and the pickup roller 12 also rotate in the clockwise direction (CW). The clockwise direction is the direction in which the first paper feed roller 71, the second paper feed roller 72, the paper feed belt 73, and the pickup roller 12 rotate in the direction in which the document is transported in the transport direction.

[0090] If the base gear 90 rotates in the clockwise direction (CW), the fourth gear 94 of the third drive mechanism 9c rotates in the counterclockwise direction (CCW). The fifth gear 95 of the third drive mechanism 9c meshing with the fourth gear 94 rotates in the clockwise direction (CW). The sixth gear 96 of the third drive mechanism 9c meshing with the fifth gear 95 rotates in the counterclockwise direction (CCW). The sixth gear 96 rotates the rotating shaft 70a of the delay roller 70 in the counterclockwise direction (CCW).

[0091] The retard roller 70 and the paper feed belt 73 face each other (see Figure 2 ). The counterclockwise direction is the direction in which the retard roller 70 rotates in the direction in which the document is transported in the transport direction. That is, when the paper feed motor 17 is rotated in the second direction, the retard roller 70 rotates in the direction in which the document is transported in the transport direction.

[0092] The direction in which the document is conveyed by the paper feed motor 17 is summarized as follows.

[0093] (1) When the paper feed motor 17 rotates in the first direction (positive direction)

[0094] Pickup roller 12, first paper feed roller 71, second paper feed roller 72, paper feed belt 73 → rotate in the direction of conveying the document in the conveying direction (downstream direction)

[0095] Retard roller 70 → rotates in a direction to send the document back to the upstream direction (the direction opposite to the conveying direction)

[0096] (2) When the paper feed motor 17 rotates in the second direction (the opposite direction)

[0097] Pickup roller 12, first paper feed roller 71, second paper feed roller 72, paper feed belt 73 → rotate in the direction of conveying the document in the conveying direction (downstream direction)

[0098] Retard roller 70 → rotates in the direction of conveying the document downstream

[0099] Thus, in the document conveying device 1, the pickup roller 12, the first paper feed roller 71, the second paper feed roller 72 and the paper feed belt 73 rotate in the direction of conveying the document downstream in the conveying direction regardless of the rotation direction of the paper feed motor 17. The retard roller 70 changes its rotation direction according to the rotation direction of the paper feed motor 17.

[0100] (Selection of reading mode)

[0101] Next, the selection of the reading mode will be described in general. In the multifunction peripheral 100 (document feeding device 1 ), either a normal mode or a manual mode can be selected as a mode used when feeding and reading a document (feed reading). For example, the mode can be selected through the operation panel 5 .

[0102] The normal mode is a mode in which the retard roller 70 is rotated in a direction in which the document is transported in the opposite direction to the transport direction of the document (in the direction of returning). In other words, the normal mode is a mode in which the document is transported while separating (dividing) the overlapping documents. The manual mode is a mode in which the retard roller 70 is rotated in a direction in which the document is transported downstream (in the direction in which the document is transported in the transport direction). The manual mode is a mode in which the document is transported without separating the document.

[0103] There is a single document formed by overlapping multiple sheets. For example, receipts for TA-Q-BIN (registered trademark) are formed by pasting carbon paper for transfer on a backing paper. In addition, there are cases where you want to read a document that has a peelable paper pasted on it, such as a label. The delay roller 70 separates the overlapping documents by friction between its surface and the document. If a document with a receipt or label pasted on it is rubbed by the delay roller 70, force is applied to the document. As a result, the pasted sheets (paper) are sometimes peeled off. In addition, there is a case where a document with a seam line for cutting is preferably not rubbed by the delay roller 70. In the case where the delay roller 70 is not desired to perform a document separation operation, the user can use the manual mode.

[0104] (Transfer reading in normal mode)

[0105] Next, based on Figure 7 An example of the flow of transport reading in the normal mode according to the embodiment will be described. Figure 7 This is a diagram showing an example of the flow of conveyance reading in the normal mode according to the embodiment.

[0106] Figure 7 The start of the operation is the moment when the operation panel 5 accepts the selection of the normal mode and the instruction to start the operation accompanied by reading. For example, the operation panel 5 accepts the operation of the start button as the start instruction. In addition, jobs such as copying and scanning and sending are jobs accompanied by reading. Since it is conveying reading, the user places the original on the original tray 11 in advance before the start instruction. The conveying control unit 10 and the main control unit 2 recognize the placement of the original based on the output of the original placement sensor 16.

[0107] First, the main control unit 2 instructs the conveying control unit 10 to start conveying reading in the normal mode (step #11). Receiving the instruction, the conveying control unit 10 causes the lifting motor 81 to raise the lifting plate 8 to the upper limit (step #12). After the lifting plate 8 starts to rise, when the lifting plate 8 (pickup roller 12) reaches the upper limit based on the output of the upper limit detection sensor 82, the conveying control unit 10 stops the lifting motor 81.

[0108] In addition, the document conveying device 1 includes a lower limit detection sensor 112 for detecting that the lifting plate 8 is located at the lower limit. For example, the lower limit detection sensor 112 is a switch that contacts the bottom surface of the lifting plate 8. The output of the lower limit detection sensor 112 is input to the conveying control unit 10. The conveying control unit 10 recognizes that the lifting plate 8 has been lowered to the lower limit based on the output of the lower limit detection sensor 112. Before the operation starts, the conveying control unit 10 lowers the lifting plate 8 to the lower limit in advance. For example, in a state where the lifting plate 8 is not located at the lower limit, when it is recognized that there is no document placed, the conveying control unit 10 rotates the lifting motor 81 to lower the lifting plate 8 to the lower limit.

[0109] After the lifting plate 8 starts to rise, the conveying control unit 10 starts to rotate the paper feed motor 17 in the first direction (positive direction) (step #13). As a result, the pickup roller 12, the first paper feed roller 71, the second paper feed roller 72, and the paper feed belt 73 rotate in the direction of conveying the original in the conveying direction of the original. The paper feeding of the original starts. The delay roller 70 rotates in the direction of returning the original in the direction opposite to the conveying direction of the original.

[0110] In addition, the retard roller 70 has a built-in torque limiter. When only one document is fed, the rotation load is higher than the set torque of the torque limiter. As a result, the retard roller 70 is driven by the paper feeding belt 73. In other words, the rotation direction of the retard roller 70 is the direction in which the document is fed in the direction in which the document is fed.

[0111] The conveyance control unit 10 recognizes that the leading end of the document has reached the feed sensor 19 based on the output of the feed sensor 19 (step #14). Then, the conveyance control unit 10 starts timing the required time T9 (step #15). Specifically, the required time T9 is the time from recognizing that the leading end of the document has reached the feed sensor 19 to recognizing that the trailing end of the document has passed the feed sensor 19.

[0112] The conveyance control unit 10 checks whether the rear end of the document has passed the feed sensor 19 (step #16). If it has not passed (No in step #16), the conveyance control unit 10 checks whether the time required for passage T9 obtained by timing exceeds a predetermined allowable time (step #17). The allowable time is predetermined according to the size of the document. The allowable time is the time used to determine whether a joint paper feeding error occurs.

[0113] The allowable time is the time obtained by dividing the length of one original in the conveying direction by the ideal (standard) original conveying speed plus a predetermined margin. In the case of joint feeding, the trailing end of the previous original overlaps the leading end of the next original and is conveyed. In this case, even if the trailing end of the previous original passes through the feed sensor 19, the feed sensor 19 cannot detect the passage.

[0114] In addition, the operation panel 5 receives the setting of the size of the original document. The conveyance control unit 10 can recognize the length of one original document in the conveyance direction based on the setting. In addition, a document size sensor for detecting the length of the original document in the conveyance direction can be provided on the document tray 11. In this case, the conveyance control unit 10 recognizes the length of the original document in the conveyance direction based on the output of the document size sensor.

[0115] When the allowed time has not been exceeded (No in step #17), the conveying control unit 10 executes step #16 (returns to step #16). When the allowed time has been exceeded (Yes in step #17), the conveying control unit 10 determines that a concomitant paper feed error has occurred (step #18). In a case where the time until the rear end passes through the detection is too long, the conveying control unit 10 determines that a concomitant paper feed error has occurred. Then, the conveying control unit 10 stops all conveyance of the original document (step #19). In other words, the conveying control unit 10 stops all motors for conveying the original document in the original document conveying device 1. Then, the conveying control unit 10 displays a message on the display panel 51 that a concomitant paper feed error has occurred (step #110). Then, the conveying control unit 10 ends this process (end). If the user wants to restart, he or she restarts from the placement of the original document.

[0116] On the other hand, when the rear end is detected to have passed (Yes in step #16), the conveyance control unit 10 stops the paper feed motor 17 (step #111). In other words, the pickup roller 12, the first paper feed roller 71, the second paper feed roller 72, the paper feed belt 73 and the retard roller 70 are stopped.

[0117] The conveyance control unit 10 conveys the document that has passed the feed sensor 19 to the discharge tray 15. The image reading device 4 reads the conveyed document. Then, the conveyance control unit 10 confirms whether there is any document remaining in the document tray 11 (lifting plate 8) (step #112). If there is no document remaining (No in step #112), the conveyance control unit 10 ends this process (end). If there is any document remaining, the conveyance control unit 10 starts step #13 (returns to step #13) after a predetermined paper feed interval has passed.

[0118] (Transport reading in single-sheet reading mode)

[0119] Next, based on Figure 8 An example of the flow of conveyance reading in the single-sheet reading mode in the manual mode according to the embodiment will be described. Figure 8 This is a diagram showing an example of the flow of conveyance reading in the single-sheet reading mode according to the embodiment.

[0120] In the multifunction machine 100 (document feeding device 1), two modes can be used as manual modes. In the manual mode, one is a single-sheet reading mode. The other is a continuous reading mode. The single-sheet reading mode is a mode for reading documents one by one. The continuous reading mode is a mode for continuously and automatically reading a plurality of documents in the manual mode.

[0121] In the following description, based on Figure 8 An example of the flow of conveyance reading in the single-sheet reading mode will be described. After the description of the single-sheet reading mode, an example of the flow of conveyance reading in the continuous reading mode will be described.

[0122] Figure 8 The start is the moment when the operation panel 5 receives the start instruction of the job accompanying the reading in the state where the single-sheet reading mode is selected. For example, the operation panel 5 receives the operation of the start button as the start instruction. The user places the original document on the original document tray 11 in advance before the start instruction. The original document placed on the original document tray 11 may be a plurality of sheets. The conveyance control unit 10 and the main control unit 2 recognize the placement of the original document based on the output of the original document placement sensor 16.

[0123] First, when the conveying reading in the single-sheet reading mode of the manual mode starts, the conveying control unit 10 causes the lifting motor 81 to raise the lifting plate 8 to the upper limit (step #21). This is the same as the normal mode. After the lifting plate 8 starts to rise, the conveying control unit 10 starts the rotation of the paper feed motor 17 in the second direction (opposite direction) (step #22). As a result, the pickup roller 12, the first paper feed roller 71, the second paper feed roller 72, and the paper feed belt 73 rotate in the direction of conveying the original downstream of the conveying direction of the original. The delay roller 70 also rotates in the direction of conveying the original downstream of the conveying direction of the original.

[0124] In the manual mode, the conveying control unit 10 slows down the conveying speed of the document compared to the normal mode (slows down in both the single-sheet reading mode and the continuous reading mode). For example, the conveying control unit 10 makes the conveying speed in the manual mode about 1 / 2 of the conveying speed in the normal mode. The conveying control unit 10 can change the rotation speed of the paper feed motor 17 in the normal mode and the manual mode.

[0125] In addition, the conveying control unit 10 can rotate the paper feeding motor 17 at the same speed in the manual mode and the normal mode. In this case, the number of teeth of the gear included in the first driving mechanism 9a and the number of teeth of the gear included in the second driving mechanism 9b are set so that the conveying speed in the manual mode is about 1 / 2 of the conveying speed in the normal mode.

[0126] The conveyance control unit 10 recognizes that the leading end of the document has reached the feed sensor 19 based on the output of the feed sensor 19 (step #23). Then, the conveyance control unit 10 controls the lift motor 81 to lower the lift plate 8 by a predetermined amount (step #24).

[0127] That is, during the period when the pickup roller 12 is conveying the document, the conveying control unit 10 causes the lifting motor 81 to start the descent of the lifting plate 8. After the descent begins, the pickup roller 12 is no longer in contact with the document. In addition, immediately after the document being fed leaves the pickup roller 12, even if the pickup roller 12 does not stop, the next document will not be fed out. In other words, even if the delay roller 70 conveys the document in the conveying direction, it is difficult for a co-feeding error to occur.

[0128] After the paper feed motor 17 (pickup roller 12) starts rotating, before the feed sensor 19 recognizes that the leading end of the document has arrived, the conveyance control unit 10 may start lowering the lifting plate 8. If the document is sandwiched between the roller gap between the retard roller 70 and the paper feed belt 73, the document is conveyed even if the pickup roller 12 is no longer in contact with the document. Therefore, the conveyance control unit 10 may cause the lifting motor 81 to start lowering the lifting plate 8 after a predetermined waiting time has passed since the rotation of the pickup roller 12 started. In this case, the waiting time is the time obtained by dividing the distance from the pickup roller 12 (the portion of the pickup roller 12 that contacts the document) to the retard roller 70 (the roller gap between the retard roller 70 and the paper feed belt 73) by the ideal conveyance speed of the document.

[0129] In addition, the paper feed motor 17 rotates the pickup roller 12. A stepper motor can be used for the paper feed motor 17. When a stepper motor is used, the rotation amount of the paper feed motor 17 and the pickup roller 12 per pulse is determined. Therefore, it can be configured that when the conveying control unit 10 inputs a pulse of a predetermined number of descent start pulses to the paper feed motor 17 from the start of rotation of the pickup roller 12, the lifting motor 81 starts to lower the lifting plate 8. In this case, the number of descent start pulses is a value obtained by dividing the distance from the pickup roller to the delay roller by the movement amount of the original per pulse. In the case where the obtained value is not an integer, the value below the decimal point can be rounded.

[0130] The amount of movement of the document per pulse is predetermined. The amount of movement of the document per pulse can be set to the amount of movement of the circumference of the pickup roller 12 when one pulse is input to the paper feed motor 17. Taking into account a slight slip, the amount of movement of the document per pulse can be a value obtained by subtracting a margin from the amount of movement of the circumference of the pickup roller 12 when one pulse is input to the paper feed motor 17.

[0131] If the lifting plate 8 is lowered by a specified amount, the conveying control unit 10 stops the lifting motor 81. The specified amount of descent can be set to a length within a range of 10 mm to 20 mm, for example. For example, the descent amount can be set to about 15 mm. For example, in the case where the lifting motor 81 is a stepping motor, the conveying control unit 10 inputs a specified number of pulses to the lifting motor 81. The specified number of pulses is the number of pulses for the lifting plate 8 to be lowered by a specified amount. The descent amount is the amount of change in the height of the downstream end edge in the document conveying direction in the upper surface of the lifting plate 8.

[0132] The descending amount can be set such that the distance from the lower end of the peripheral surface of the pickup roller 12 to the next original document of the uppermost original document is greater than a predetermined separation distance. In other words, the original document is reliably separated from the lower end of the peripheral surface of the pickup roller 12. Furthermore, the descending amount is set to a value such that the original document on the lifting plate 8 is not below a predetermined lower limit height, so that the original document does not sag excessively.

[0133] When the leading edge of the document is detected reaching the feed sensor 19, the conveyance control unit 10 starts counting the required passage time T9 (step #25). The required passage time T9 is the time from when the leading edge of the document is detected reaching the feed sensor 19 to when the trailing edge of the document is detected passing the feed sensor 19.

[0134] The conveying control unit 10 checks whether the rear end of the document has passed the feed sensor 19 (step #26). If it has not passed (No in step #26), the conveying control unit 10 checks whether the time required for passage T9 obtained by timing exceeds the allowed time (step #27). The conveying speed in the manual mode is about 1 / 2 of that in the normal mode, so the allowed time in the manual mode is about twice that in the normal mode.

[0135] When the allowed time has not been exceeded (No in step #27), the conveying control unit 10 executes step #26 (returns to step #26). When the allowed time has been exceeded (Yes in step #27), the conveying control unit 10 determines that a concomitant paper feed error has occurred (step #28). When the rear end passes through the detection delay, the conveying control unit 10 determines that a concomitant paper feed error has occurred. Then, the conveying control unit 10 stops all conveyance of the original document (step #29). In other words, the conveying control unit 10 stops all motors for conveying the original document in the original document conveying device 1. Then, the conveying control unit 10 causes the display panel 51 to display a message that a concomitant paper feed error has occurred (step #210). Then, the conveying control unit 10 ends this process (end). If the user wants to restart, he or she restarts from the placement of the original document.

[0136] On the other hand, when the rear end is recognized to have passed (Yes in step #26), the conveyance control unit 10 stops the paper feed motor 17 (step #211). That is, the pickup roller 12, the first paper feed roller 71, the second paper feed roller 72, the paper feed belt 73, and the delay roller 70 are stopped. The conveyance control unit 10 conveys the original document that has passed the feed sensor 19 to the discharge tray 15. The image reading device 4 reads the conveyed original document. Then, the conveyance control unit 10 ends this process (end).

[0137] The single-sheet reading mode is a mode in which the user reads the originals one by one by indicating the start of the job for each original (operating the start button). In addition, multiple originals can be placed on the original tray 11 in the single-sheet reading mode. If the user wants to continue reading in the single-sheet reading mode, the user again issues the start instruction of the job. Figure 8 The process starts again.

[0138] (Flow of operations in continuous reading mode)

[0139] Next, based on Fig. 9 An example of the flow of transport reading in the continuous reading mode according to the embodiment will be described. Fig. 9 This is a diagram showing an example of the flow of transport reading in the continuous reading mode according to the embodiment.

[0140] Fig. 9 The start is the moment when the operation panel 5 receives the start instruction (operation of the start button) of the job accompanying reading in the state where the continuous reading mode is selected. The user places the original on the original tray 11 in advance before the start instruction. In the case of the continuous reading mode, the placed originals are multiple sheets. The conveying control unit 10 and the main control unit 2 recognize the placement of the original based on the output of the original placement sensor 16.

[0141] First, when conveyance reading in the continuous reading mode of the manual mode is started, the conveyance control unit 10 causes the lift motor 81 to raise the lift plate 8 to the upper limit (step #31). This is the same as in the normal mode and the single-sheet reading mode.

[0142] Continuous Read Mode ( Fig. 9 ) steps #32 to #311 and single-sheet reading mode ( Figure 8 Therefore, the description of steps #22 to step #211 can be referred to for steps #32 to step #311, and the description is omitted here.

[0143] When the rear end of the document passes through the feed sensor 19 (Yes in step #36), the paper feed motor 17 stops (step #311), and the conveyance control unit 10 checks whether there is a document placed on the lift plate 8 (document tray 11) (step #312). Specifically, the conveyance control unit 10 checks the output of the document placement sensor 16.

[0144] If no document is set (No in step #312), the conveyance control unit 10 ends this flow (end). If a document is set (Yes in step #312), the conveyance control unit 10 executes step #31 (returns to step #31).

[0145] That is, the conveying control unit 10 raises the lifting plate 8 that has been lowered by the lowered amount again. The conveying control unit 10 rotates the lifting motor 81. The conveying control unit 10 raises the lifting plate 8 again until the topmost original document contacts the pickup roller 12 (the pickup roller 12 and the lifting plate 8 rise to the upper limit). After rising again, the conveying control unit 10 executes step #32 to start paper feeding. That is, the conveying control unit 10 rotates the pickup roller 12, the first paper feed roller 71, the second paper feed roller 72, the paper feed belt 73 and the delay roller 70. The conveying control unit 10 rotates the above-mentioned rotating body in the direction of conveying the original document in the conveying direction.

[0146] (Action in manual mode)

[0147] Next, based on Fig.10 An example of the operation in the manual mode according to the embodiment will be described. Fig.10 This is a timing chart showing an example of the operation in the manual mode according to the embodiment.

[0148] exist Fig.10 In the timing diagram, the top timing diagram is a timing diagram showing the operation of the lift motor 81, the middle timing diagram is a timing diagram showing the operation of the paper feed motor 17, and the bottom timing diagram is a diagram showing an example of the output level of the feed sensor 19. Fig.10 The feed sensor 19 in the example outputs a High level when the document is detected, and outputs a Low level when the document is not detected.

[0149] Fig.10 The time T1 is the time when the lifting plate 8 starts to rise. The conveying control unit 10 rotates the lifting motor 81 in the direction of the lifting plate 8 rising. The conveying control unit 10 accelerates the lifting motor 81 and rotates it at a predetermined speed. The time T2 is the time when the conveying control unit 10 recognizes that the lifting plate 8 has reached the upper limit. The conveying control unit 10 starts to stop the lifting motor 81.

[0150] Time T3 is the time when the conveyance control unit 10 starts the rotation of the paper feed motor 17. The conveyance control unit 10 rotates the paper feed motor 17 in the second direction (the reverse direction). Fig.10 In FIG. 1 , the state in which the paper feed motor 17 rotates is illustrated at a Low level.

[0151] Time T4 is when the conveyance control unit 10 recognizes that the leading end of the document reaches the feed sensor 19 based on the output of the feed sensor 19. At this time, the conveyance control unit 10 rotates the lift motor 81. The conveyance control unit 10 rotates the lift motor 81 in the direction in which the lift plate 8 is lowered.

[0152] Time T5 is the time when the lifting motor 81 stopped rotating by the conveying control unit 10. By this descent, the lifting plate 8 is lowered by a predetermined descent amount. Time T6 is the time when the conveying control unit 10 temporarily stops the rotation of the paper feed motor 17. After recognizing that the front end of the original reaches the feed sensor 19, the conveying control unit 10 continues to rotate the paper feed motor 17. Due to the continued rotation of the paper feed motor 17, the front end of the original collides with the registration roller pair 13 in the stopped state, and the original bends. It is preferable not to bend excessively. Therefore, after recognizing that the front end of the original reaches the feed sensor 19, the conveying control unit 10 stops the paper feed motor 17 at time T6 after the deflection production time.

[0153] The time T7 is the time when the transport control unit 10 restarts the rotation of the paper feed motor 17. At this time, the transport control unit 10 also rotates the paper feed motor 17 in the second direction. At the time T7, the transport control unit 10 also starts the rotation of the registration roller pair 13.

[0154] Time T8 is the time when the feed sensor 19 detects the passage of the rear end of the document. The transport control unit 10 recognizes that the rear end of the document has passed the feed sensor 19 based on the output of the feed sensor 19. The transport control unit 10 stops the paper feed motor 17 based on this recognition.

[0155] (Selection of mode)

[0156] Next, based on Fig.11 An example of the mode selection screen 54 according to the embodiment will be described. Fig.11 It is a diagram showing an example of the mode selection screen 54 according to the embodiment.

[0157] Any of the normal mode, single-frame reading mode, and continuous reading mode can be selected. Fig.11 An example of a mode selection screen 54 related to reading is shown. When the operation panel 5 receives an operation for displaying the mode selection screen 54, the main control unit 2 causes the display panel 51 to display the mode selection screen 54. The user selects a mode before starting a task of reading a document.

[0158] In addition, when a job execution start instruction is given without selecting a mode, the main control unit 2 instructs the conveying control unit 10 to convey and read in the default mode. The conveying control unit 10 feeds and conveys the original in the default mode based on the instruction. The default mode is predetermined. The operation panel 5 can accept the selection of the default mode. For example, the normal mode is the default mode.

[0159] The mode selection screen 54 includes a normal mode selection button B1 , a single-sheet reading mode selection button B2 , a continuous reading mode selection button B3 , and an automatic change permission check box C1 .

[0160] When the user wants to convey the document in the normal mode, the user operates the normal mode selection button B1. When the user wants to convey the document in the single-sheet reading mode, the user operates the single-sheet reading mode selection button B2. When the user wants to convey the document in the continuous reading mode, the user operates the continuous reading mode selection button B3. The main control unit 2 recognizes the selected mode based on the output of the operation panel 5. When the document reading starts, the main control unit 2 notifies the conveying control unit 10 of the selected mode.

[0161] In this way, the operation panel 5 receives the selection of which mode to use, the normal mode or the manual mode. The transport control unit 10 reads the document in the selected mode.

[0162] The automatic change permission check box C1 is a check box for selecting whether to permit the automatic change of the mode in the manual mode. When permitting the automatic change, the user operates the automatic change permission check box C1 to check it. When not permitting the automatic change, the user operates the automatic change permission check box C1 to uncheck it. The main control unit 2 recognizes whether or not a check is made based on the output of the operation panel 5.

[0163] When the document reading starts, the main control unit 2 notifies the conveyance control unit 10 whether the mode can be changed automatically. When receiving the notification that the automatic change is allowed, the conveyance control unit 10 automatically changes (selects) the mode when the document is being conveyed and read and the manual mode is selected. When receiving the notification that the automatic change is not allowed, the conveyance control unit 10 maintains the mode selected on the mode selection screen 54.

[0164] When the normal mode is selected (normal mode selection button B1 is operated) and a plurality of documents are placed on the lift plate 8 , the transport control unit 10 rotates the retard roller 70 in a direction to transport all the documents in the direction opposite to the document transport direction.

[0165] (Automatic change from continuous scanning mode to single scanning mode)

[0166] Next, based on Fig.12 An example of a flow of automatic switching from the continuous scanning mode to the single-sheet scanning mode according to the embodiment will be described. Fig.12 This is a diagram showing an example of a flow of automatic change from the continuous reading mode to the single-sheet reading mode according to the embodiment.

[0167] start Fig.12 There are two cases of "start". The first is the moment when the manual mode's continuous reading mode starts feeding and reading in the state where the automatic change is allowed. In other words, it is the moment when the first original is fed in the continuous reading mode in the state where the automatic change is allowed. The second is the moment when the original is first fed after the automatic change (automatic selection) to the continuous reading mode is performed by the automatic change.

[0168] The conveyance control unit 10 checks whether there is (or remains) an original document on the lift plate 8 (step #41). If no original document remains on the lift plate 8 (No in step #41), the conveyance control unit 10 ends the processing of this flow (end).

[0169] Next, the conveyance control unit 10 checks whether a feeding error has occurred in the document being fed (step #42). In other words, the conveyance control unit 10 checks whether the rear end of the currently fed document has passed the feed sensor 19 within the allowed time.

[0170] If no associated paper feeding error occurs (No in step #42), the conveyance control unit 10 maintains the continuous reading mode (step #43). Then, the conveyance control unit 10 automatically starts feeding the next original document in the continuous reading mode (step #44). Specifically, the conveyance control unit 10 automatically raises the lifting plate 8 and restarts the rotation of the paper feeding motor 17. Then, the conveyance control unit 10 executes step #41 (returns to step #41).

[0171] When a paper feeding error occurs (Yes in step #42), it may not be preferable to feed the original in the continuous reading mode. Therefore, the conveyance control unit 10 automatically changes the mode to the single-sheet reading mode (automatically selects the single-sheet reading mode) (step #45). Since the single-sheet reading mode is automatically selected, the conveyance control unit 10 ends the processing of this flow based on the continuous reading mode (end).

[0172] (Automatic change from single-frame scanning mode to continuous scanning mode)

[0173] Next, based on Fig.13 An example of a flow of automatic switching from the single-sheet reading mode to the continuous reading mode according to the embodiment will be described. Fig.13This is a diagram showing an example of a flow of automatic change from the single-sheet reading mode to the continuous reading mode according to the embodiment.

[0174] start Fig.13 There are two cases of "start". The first is the moment when the conveying reading in the single-sheet reading mode of the manual mode is started in the state of automatic change of the mode. In other words, the moment when the original is fed in the single-sheet reading mode is started in the state of automatic change permission. The second is the moment when the original is fed after the automatic change to the single-sheet reading mode is performed by automatic change.

[0175] The conveyance control unit 10 checks whether there is (or remains) an original document on the lift plate 8 (step #51). If no original document remains on the lift plate 8 (No in step #51), the conveyance control unit 10 ends the processing of this flow (end).

[0176] Next, the conveyance control unit 10 checks whether a feeding error has occurred in the document being fed (step #52). In other words, the conveyance control unit 10 checks whether the rear end of the currently fed document has passed the feed sensor 19 within the allowed time.

[0177] If a joint paper feeding error occurs (Yes at step #52), paper feeding of the document in the continuous reading mode may not be preferable. Therefore, the transport control unit 10 maintains the single-sheet reading mode (step #53).

[0178] After the error in paper feeding is corrected, if the operation panel 5 receives a reading start instruction, the conveyance control unit 10 starts feeding the next document in the single-sheet reading mode (step #54). Specifically, when the start button is operated, the conveyance control unit 10 starts the lifting of the lifting plate 8 and the rotation of the paper feeding motor 17. Then, the conveyance control unit 10 executes step #51 (returns to step #51).

[0179] If no associated paper feeding error occurs (No in step #52), the conveyance control unit 10 adds 1 to the paper feeding success count value (step #55). The paper feeding success count value is stored in, for example, the memory 10b of the conveyance control unit 10. In addition, when there is no original on the lifting plate 8, or a predetermined reset time has passed since the last paper feeding of the original, the conveyance control unit 10 resets the paper feeding success count value (to "0").

[0180] The conveyance control unit 10 checks whether the number of successful paper feedings has reached a predetermined number of times (step #56). In other words, when multiple documents are placed in the single-sheet reading mode, the conveyance control unit 10 checks whether the documents can be fed continuously for a predetermined number of times without any problems.

[0181] When the number of successful paper feedings does not reach the prescribed number of times (No in step #56), if the operation panel 5 receives a reading start instruction, the conveyance control unit 10 starts to feed the next original document in the single-sheet reading mode (step #57). That is, when the number of successful paper feedings does not reach the prescribed number of times (No in step #56), the conveyance control unit 10 maintains the single-sheet reading mode. After step #57, the conveyance control unit 10 executes step #51 (returns to step #51).

[0182] When the number of successful paper feedings reaches the specified number of times (Yes in step #56), it is considered that there is no problem even if the continuous reading mode is switched. Therefore, the conveyance control unit 10 automatically changes the mode (automatically selects) to the continuous reading mode (step #58). Since the continuous reading mode is selected, the conveyance control unit 10 ends the processing of this flow based on the single-sheet reading mode (end).

[0183] (When automatic mode change is not permitted)

[0184] Next, based on Fig.14 An example of the operation when the automatic change of the mode is not permitted will be described. Fig.14 This is a diagram showing an example of the operation when the automatic change of the mode is not permitted.

[0185] The operation panel 5 accepts a selection of which of the normal mode and the manual mode to use. That is, the operation panel 5 accepts a selection of using only the normal mode. When the normal mode is selected, the conveyance control unit 10 maintains the paper feeding and conveyance of the normal mode from the first sheet to the last sheet of the document.

[0186] In addition, the operation panel 5 accepts a selection to use only the continuous reading mode. In other words, the operation panel 5 accepts the following operation as a selection to use only the continuous reading mode: an operation of the continuous reading mode selection button B3 in a state where the automatic change permission check box C1 is not checked. In this case, the conveyance control unit 10 does not automatically change to the single-sheet reading mode during the continuous reading mode.

[0187] In addition, the operation panel 5 accepts the selection of using only the single-sheet reading mode. In other words, the operation panel 5 accepts the following operation as the selection of using only the single-sheet reading mode: the operation of the single-sheet reading mode selection button B2 in a state where the automatic change permission check box C1 is not checked. In this case, the conveyance control unit 10 does not automatically change to the continuous reading mode during the single-sheet reading mode.

[0188] Thus, the document conveying device 1 involved in the embodiment includes a lifting plate 8, a pickup roller 12, a lifting motor 81, a delay roller 70, and a control unit (conveying control unit 10). The document is placed on the lifting plate 8. The pickup roller 12 contacts the topmost document among the documents placed on the lifting plate 8. The pickup roller 12 rotates to convey the document in the conveying direction of the document. The lifting motor 81 raises and lowers the lifting plate 8. When paper feeding starts, the lifting motor 81 raises the lifting plate 8 until the pickup roller 12 contacts the topmost document. The delay roller 70 is set at a position downstream of the pickup roller 12 in the conveying direction of the document. The delay roller 70 contacts the document fed by the pickup roller 12. When the normal mode is selected, the control unit rotates the delay roller 70 in a direction to convey the document in the opposite direction to the conveying direction of the document. When the manual mode is selected, the control unit rotates the delay roller 70 in a direction to convey the document in the conveying direction of the document. When the manual mode is selected, the control unit controls the lift motor 81 to start lowering the lift plate 8 after the pickup roller 12 starts rotating while the pickup roller 12 is conveying the document.

[0189] The lifting plate 8 can be lowered in the middle of conveying the document. By lowering the lifting plate 8, the document is no longer in contact with the pickup roller 12. Even if the pickup roller 12 stops, the next document is not fed out immediately after the supplied document leaves the pickup roller 12.

[0190] In addition, a gap can be formed between the document being transported (the top document) and the second document from the top. It is possible to prevent the document below the second document from being pulled by the document being transported (the top document). In the transportation of the top document, it is possible to reduce the number of documents below the second document from the top entering the delay roller 70. In the manual mode, the delay roller 70 rotates in the direction of transporting the document in the transport direction. Even if the delay roller 70 does not play the function of preventing co-feeding and overlapping transport, it can suppress the occurrence of co-feeding and overlapping transport of the document.

[0191] In addition, the pickup roller 12 does not press the placed original document. If the pickup roller 12 presses the uppermost original document, the original document below the uppermost original document may be pulled by the uppermost original document. By lowering the lifting plate 8, the force of the pickup roller 12 pressing the original document bundle can be weakened.

[0192] After the time obtained by dividing the distance from the pickup roller 12 to the retard roller 70 by the ideal conveying speed of the document has passed since the pickup roller 12 started to rotate, the control unit causes the lifting motor 81 to start lowering the lifting plate 8. The lifting plate 8 can be lowered from the moment when the retard roller 70 catches the leading end of the document. In other words, even if the top document is separated from the pickup roller 12, the lifting plate 8 can be lowered from the state where the top document is continuously fed. The lifting plate 8 can be immediately lowered at a moment when there is no problem even if the lifting plate 8 is lowered.

[0193] The document feeding device 1 includes a feed sensor 19. The feed sensor 19 is provided at a position downstream of the delay roller 70 in the document feeding direction. The control unit recognizes that the leading end of the document has reached the feed sensor 19 based on the output of the feed sensor 19. If it is recognized that the leading end of the document has reached the feed sensor 19, the control unit causes the lifting motor 81 to start lowering the lifting plate 8. The lifting plate 8 can be lowered at a time when the document is continuously fed even when the lifting plate 8 is lowered. Even when the lifting plate 8 is lowered, the document can be fed downstream in the document feeding direction without any problem.

[0194] Alternatively, when the paper feed motor 17 is a stepping motor, the control unit can cause the lifting motor 81 to start lowering the lifting plate 8 when a pulse of a predetermined number of pulses for starting the descent is input to the paper feed motor 17 from the start of the rotation of the pickup roller 12. In this case, the number of pulses for starting the descent is a value obtained by dividing the distance from the pickup roller 12 to the delay roller 70 by the amount of movement of the document per pulse. In this way, the lifting plate 8 can be started to be lowered at a time when the document is continuously conveyed even when the lifting plate 8 is lowered. Even when the lifting plate 8 is lowered, the document can be conveyed downstream in the document conveying direction without any problem.

[0195] The control unit recognizes that the rear end of the document has passed the feed sensor 19 based on the output of the feed sensor 19. When recognizing that the rear end of the document has passed the feed sensor 19, the control unit stops the rotation of the pickup roller 12 and the delay roller 70. As long as one document is reliably fed out from the lifting plate 8, the feed sensor 19 recognizes that the rear end has passed. At the moment when it can be determined that one document has been reliably fed out, the rotation of the pickup roller 12 and the delay roller 70 can be stopped. The lifting plate 8 descends, so even if the pickup roller 12 continues to rotate after the document passes through it, the next document will not be fed in the conveying direction. The pickup roller 12 and the delay roller 70 can be rotated appropriately.

[0196] The control unit measures the required time T9 from when the front end of the manuscript is recognized to arrive at the feed sensor 19 to when the rear end of the manuscript is recognized to pass through the feed sensor 19. The control unit detects the occurrence of a contiguous paper feeding error of the manuscript based on the length of the required time T9. When the contiguous paper feeding error is detected, the control unit stops the rotation of the pickup roller 12 and the delay roller 70. The occurrence of a contiguous paper feeding error can be detected. When a contiguous paper feeding occurs, the manuscript may get stuck (paper jam). The transportation of the manuscript can be stopped to avoid damage to the manuscript due to the jam.

[0197] After the pickup roller 12 starts to rotate, when the lifting plate 8 is lowered while the pickup roller 12 is conveying the document, the control unit lowers the lifting plate 8 by a predetermined amount. The lifting plate 8 can be lowered appropriately. Excessive lowering of the lifting plate 8 can be prevented without causing co-feeding of the document.

[0198] The amount of descent is a value within a range where the distance from the lower end of the circumference of the pickup roller 12 to the next original of the top original becomes greater than a predetermined separation distance and the original on the lifting plate 8 is not lower than a predetermined lower limit height. The pickup roller 12 can be fully separated from the original. If the top original droops significantly, the original must be conveyed while being pulled. If it droops significantly, the image quality of the image data obtained by reading may be reduced. Since the lifting plate 8 is not excessively lowered, it is possible to avoid excessive drooping of the top original (the original being conveyed).

[0199] The control unit makes the conveying speed of the document slower in the manual mode than in the normal mode. Since the conveying speed of the document is suppressed in the manual mode, damage to the document when an error occurs can be eliminated or reduced.

[0200] The document transport device 1 includes a paper feed motor 17, a first drive mechanism 9a, a second drive mechanism 9b, and a third drive mechanism 9c. The paper feed motor 17 rotates the pickup roller 12 and the delay roller 70. When the paper feed motor 17 is rotated in a first direction, the first drive mechanism 9a rotates the pickup roller 12 in a direction in which the document is transported in the document transport direction. When the paper feed motor 17 is rotated in a second direction which is opposite to the first direction, the second drive mechanism 9b rotates the pickup roller 12 in a direction in which the document is transported in the document transport direction.

[0201] When the paper feed motor 17 is rotated in the first direction, the third drive mechanism 9c rotates the delay roller 70 in the direction of conveying the document in the opposite direction to the conveying direction of the document. When the paper feed motor 17 is rotated in the second direction, the third drive mechanism 9c rotates the delay roller 70 in the direction of conveying the document in the conveying direction of the document. The pickup roller 12 and the delay roller 70 can be rotated in the correct direction in each mode. By using the first drive mechanism 9a, the second drive mechanism 9b and the third drive mechanism 9c, the motor that rotates the pickup roller 12 and the delay roller 70 can be a single paper feed motor 17.

[0202] In addition, the document feeding device 1 further includes a document placement sensor 16 and an operation panel 5. The document placement sensor 16 detects whether a document is placed on the lifting plate 8. The operation panel 5 receives a mode selection. When the normal mode is selected, the control unit rotates the pickup roller 12 in a direction in which the document is transported in the transport direction of the document, and rotates the delay roller 70 in a direction in which the document is transported in the opposite direction to the transport direction of the document. When the manual mode is selected, the control unit rotates the pickup roller 12 and the delay roller 70 in a direction in which the document is transported in the transport direction of the document. After the rotation of the pickup roller 12 starts, the control unit causes the lifting motor 81 to start lowering the lifting plate 8 while the pickup roller 12 transports the document. The control unit stops the pickup roller 12 and the delay roller 70 after the rear end of the document is separated from the delay roller 70. In addition, when the continuous reading mode in the manual mode is selected, the control unit recognizes whether there is a document placed on the lifting plate 8 based on the output of the document placement sensor 16. When the pickup roller 12 and the retard roller 70 are stopped, if there is a document placed on the lifting plate 8, the control unit raises the lifting plate 8 again until the top document contacts the pickup roller 12. After the lifting is completed again, the control unit rotates the pickup roller 12 and the retard roller 70 in the direction of conveying the document in the conveying direction of the document, and automatically restarts the paper feeding in the manual mode.

[0203] The lifting plate 8 can be lowered in the middle of conveying the original. By lowering the lifting plate 8, the original being conveyed no longer contacts the pickup roller 12. In addition, a gap can be formed between the original being conveyed (the topmost original) and the second original from the top. The original below the second from the top can be prevented from being pulled by the original being conveyed. The occurrence of co-feeding can be suppressed.

[0204] In addition, in the continuous reading mode, multiple originals can be continuously fed one by one in the manual mode. In the process of feeding the originals one by one, the lifting plate 8 is automatically raised and lowered, and the rollers are rotated. It is not necessary to instruct the lifting plate 8 to rise again and to start the original feeding (reading) every time a document is fed. Multiple originals can be automatically read in the manual mode without overlapping feeding and joint feeding.

[0205] The control unit measures the time T9 required for the document to pass from the time when the front end of the document reaches the feed sensor 19 to the time when the rear end of the document passes the feed sensor 19. The control unit detects whether a contiguous paper feeding error of the document occurs based on the length of the time T9 required for the document to pass. When a contiguous paper feeding error is detected in the continuous reading mode, the control unit automatically selects the single-sheet reading mode. The single-sheet reading mode is one of the manual modes. In the single-sheet reading mode, after the operation panel 5 receives the single-sheet reading start instruction, the control unit raises the lifting plate 8 and feeds one document in the manual mode.

[0206] It is difficult to completely reduce the number of occurrences of consecutive paper feed errors to zero. Therefore, when a consecutive paper feed error is detected during reading in the continuous reading mode, the manual mode can be automatically changed from the continuous reading mode to the single-sheet reading mode. The single-sheet reading mode is a mode for reading the original document in units of one sheet. It can be automatically switched to a mode for reading while checking each sheet one by one to avoid the occurrence of consecutive paper feed errors.

[0207] When a predetermined number of documents are fed without a concatenated paper feed error in the single-sheet reading mode, the control unit automatically selects the continuous reading mode. When the possibility of a concatenated paper feed error in the continuous reading mode is considered low, the single-sheet reading mode can be automatically switched to the continuous reading mode.

[0208] The operation panel 5 accepts a selection to use only the continuous reading mode. When the selection to use only the continuous reading mode is made, the control unit does not automatically change to the single-sheet reading mode during the continuous reading mode. There are also users who do not want to perform the automatic mode switch to the single-sheet reading mode. For users who do not want the automatic switch, they can continue to use only the desired mode (continuous reading mode only).

[0209] The operation panel 5 accepts a selection to use only the single-sheet reading mode. When the selection to use only the single-sheet reading mode is made, the control unit does not automatically select the continuous reading mode during the single-sheet reading mode. There are also users who do not want the automatic mode switch to the continuous reading mode. For users who do not want the automatic switch, they can continue to use the desired mode (single-sheet reading mode only).

[0210] The operation panel 5 receives a selection of which of the normal mode and the manual mode to use. The control unit reads the document in the selected mode. The user can select whether to use the normal mode or the manual mode. The document can be read in the selected mode.

[0211] The system includes an overlapped feed detection sensor 111 for detecting overlapped feed of a document. The output of the overlapped feed detection sensor 111 is input to the control unit. When paper is fed in the normal mode, the control unit determines whether overlapped feed occurs based on the output of the overlapped feed detection sensor 111. When paper is fed in the manual mode, the control unit does not determine whether overlapped feed occurs based on the output of the overlapped feed detection sensor 111. The manual mode assumes the feeding and conveyance of a document consisting of a plurality of overlapping sheets, such as a document. In the manual mode, even if a single document consisting of a plurality of overlapping sheets is fed and conveyed, it is not erroneously detected as overlapped feed.

[0212] As mentioned above, although embodiment of this invention was described, the scope of this invention is not limited to this, It can add various changes and implement within the range which does not deviate from the summary of this invention.

[0213] Possibility of Industrial Application

[0214] The present invention can be applied to a document conveying device that uses a lift plate to bring a document into contact with a pickup roller.

Claims

1. A document conveying device, characterized in that: include: an original tray including a lifting plate on which an original to be read by the image reading device is placed; A pickup roller contacts the topmost original among the originals placed on the lifting plate and rotates to transport the originals in a transport direction of the originals; A lifting motor is used to raise and lower the lifting plate, and when paper feeding starts, the lifting plate is raised until the topmost original document contacts the pickup roller; a retard roller disposed at a position downstream of the pickup roller in a conveying direction of the original document and in contact with the original document fed by the pickup roller; as well as a control unit that controls the pickup roller, the lift motor, and the retard roller according to a conveying reading mode of the original document placed on the lift plate, The conveying and reading modes include a normal mode and a manual mode. When the normal mode is selected as the transport reading mode, the control unit rotates the retard roller in a direction to transport the document in a direction opposite to the transport direction of the document. When the manual mode is selected as the transport reading mode, the control unit rotates the delay roller in a direction to transport the document in the transport direction of the document, and after the pickup roller starts to rotate, while the pickup roller is transporting the document, the control unit starts the lifting motor to lower the lifting plate. When the lifting plate is not at the lower limit and it is recognized that there is no document placed, the control unit rotates the lifting motor to lower the lifting plate to the lower limit.

2. The document feeding device according to claim 1, characterized in that: The control unit controls the lift motor to start lowering the lift plate after a time obtained by dividing a distance from the pickup roller to the retard roller by an ideal conveyance speed of the document has passed since the pickup roller starts rotating.

3. The document feeding device according to claim 1, characterized in that: A feed sensor is provided at a downstream side of the retard roller in a conveying direction of the document. The control unit recognizes that the leading end of the document reaches the feed sensor based on the output of the feed sensor, The control unit controls the lift motor to start lowering the lift plate when recognizing that the leading end of the document has reached the feed sensor.

4. The document feeding device according to claim 1, characterized in that: A paper feed motor is included, which rotates the pickup roller. The paper feed motor is a stepping motor, The control unit inputs pulses of a predetermined number of descent start pulses to the paper feed motor from the start of rotation of the pickup roller, and after a time corresponding to the number of descent start pulses has passed since the input, the control unit causes the lift motor to start lowering the lift plate. The number of falling start pulses is a value obtained by dividing the distance from the pickup roller to the retard roller by the movement amount of the document per pulse.

5. The document feeding device according to claim 1, characterized in that: A feed sensor is provided at a position downstream of the retard roller in the conveying direction. The control unit recognizes that the rear end of the document has passed the feed sensor based on the output of the feed sensor, The control unit stops the rotation of the pickup roller and the retard roller when recognizing that the rear end of the document has passed the feed sensor.

6. The document feeding device according to claim 3, characterized in that: The control unit measures a time required for passage from when the leading end of the document is recognized to reach the feed sensor to when the trailing end of the document is recognized to pass through the feed sensor. The control unit detects whether a co-feed error of the document occurs based on the length of the time required for the passage, The control unit stops the rotation of the pickup roller and the retard roller when the occurrence of the joint paper feed error is detected.

7. The document feeding device according to claim 1, characterized in that: When the lift plate is lowered while the pickup roller is conveying a document after the pickup roller starts rotating, the control unit lowers the lift plate by a predetermined amount of lowering.

8. The document feeding device according to claim 1, characterized in that: The lowering amount is a value within a range in which a distance from a lower end of the peripheral surface of the pickup roller to the document next to the uppermost document is greater than a predetermined separation distance and the document on the lift plate does not fall below a predetermined lower limit height.

9. The document feeding device according to claim 1, characterized in that: The control unit makes the conveyance speed of the document slower in the manual mode than in the normal mode.

10. The document feeding device according to claim 1, characterized in that: include: A paper feed motor to rotate the pickup roller and the retard roller; a first driving mechanism for rotating the pickup roller in a direction for conveying the document in a conveying direction of the document when the paper feed motor rotates in a first direction; a second driving mechanism for rotating the pickup roller in a direction for conveying the document in the conveying direction of the document when the paper feed motor rotates in a second direction which is opposite to the first direction; as well as The third driving mechanism rotates the delay roller in a direction to transport the document in a direction opposite to the transport direction of the document when the paper feed motor rotates in the first direction, and rotates the delay roller in a direction to transport the document in the transport direction of the document when the paper feed motor rotates in the second direction.

Images