Sheet feeding device, script feeding device, and image forming device

Abstract

To obtain sufficient pressure to hold scripts when a script feeding device is lifted.SOLUTION: A script feeding device 1 includes a script tray 61 on which a script 10 is placed, a pickup roller 68 that feeds the script 10 from the script tray 61, and pressure means 60 that applies pressure to the script 10 by sandwiching it between the script tray 61 and the pickup roller 68, the script feeding device 1 is configured to be switchable between a lift-down state in which the script 10 is placed on an image reading part 2 in a state in which it can be fed, and a lift-up state in which the script feeding device is lifted from the image reading part 2 so as to be inclined from the lift-down state, the pressure on the script 10 sandwiched between the script tray 61 and the pickup roller 68 when the script feeding device 1 is in the lift-up state is greater than the pressure on the script 10 sandwiched between the script tray 61 and the pickup roller 68 when the script feeding device 1 is in the lift-down state and in a state in which the script 10 can be fed.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a sheet feeding device, a document feeding device, and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art As an example of a sheet feeding device, a document feeding device that feeds a document to an image reading unit in an image forming apparatus such as a copying machine or a printer is known.

[0003] Generally, a document feeder includes a document placement section for placing a document, a transport means for transporting the document from the placement section to an image reading section, etc. When a user presses the print key with a document placed on the placement section, the document is transported from the placement section to the image reading section, and the image of the document is read by the image reading section.

[0004] In addition, one method for reading an image on a document involves lifting the document feeder into a lift-up state, placing the document on the contact glass of the image reading unit, and reading the image. However, if the document feeder is lifted while the document is placed on the placement unit, there is a problem in that the document falls off the placement unit.

[0005] To address this problem, for example, Patent Document 1 (JP Patent Publication No. 11-237770) proposes a configuration in which, when the document feeder is lifted, the bottom plate is raised and the document is sandwiched and pressed between the bottom plate and the pick-up roller. With this configuration, the document is held in place by the bottom plate and the pick-up roller, preventing the document from falling when the document feeder is lifted. Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, no consideration is given to the pressure force that holds the document when the document feeder is lifted.

[0007] Therefore, an object of the present invention is to provide a sufficient pressure force to hold the sheet when a sheet feeding device such as a document feeding device is lifted. [Means for solving the problem]

[0008] In order to solve the above problem, the present invention provides a sheet feeding device comprising a loading section for loading a sheet, a feeding member for feeding the sheet from the loading section, and a pressure means for pressing the sheet between the loading section and the feeding member, wherein the sheet feeding device is configured to be switchable between a lift-down state in which the sheet is placed on a base section in a state in which it can be fed, and a lift-up state in which it is lifted from the base section so as to be inclined from the lift-down state, and wherein the pressure force of the sheet sandwiched between the loading section and the feeding member when the sheet feeding device is in the lift-up state is greater than the pressure force of the sheet sandwiched between the loading section and the feeding member when the sheet feeding device is in the lift-down state and in a state in which it can feed the sheet. [Effects of the Invention]

[0009] According to the present invention, a sufficient pressure force for holding the sheet when the sheet feeding device is lifted can be obtained. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating the overall configuration of an image forming apparatus according to a first embodiment of the present invention. [Figure 2] 1 is a side view of an image forming apparatus according to a first embodiment of the present invention, as viewed from the left side in FIG. [Figure 3] FIG. 2 is a diagram showing a detailed configuration of the document feeding device according to the first embodiment of the present invention. [Figure 4] FIG. 2 is a block diagram of a control system of the document feeding device according to the first embodiment of the present invention. [Figure 5] 1 is a front view of a document feeding device according to a first embodiment of the present invention. [Figure 6]6 is a side view of the document feeding device according to the first embodiment of the present invention, as viewed from the left side in FIG. 5. FIG. [Figure 7] FIG. 2 is a diagram showing the configuration of a pressure means according to the first embodiment of the present invention. [Figure 8] 5A and 5B are diagrams illustrating a pressing operation of a pressing unit according to the first embodiment of the present invention. [Figure 9] 5A and 5B are diagrams illustrating a pressing operation of a pressing unit according to the first embodiment of the present invention. [Figure 10] 5A and 5B are diagrams illustrating a pressing operation of a pressing unit according to the first embodiment of the present invention. [Figure 11] FIG. 10 is a side view of a document feeding device according to a second embodiment of the present invention. [Figure 12] FIG. 10 is a diagram showing a state in which the document feeding device according to the second embodiment of the present invention is lifted up from a lift-down state so as to be inclined at a predetermined angle. [Figure 13] FIG. 10 is a diagram showing a state in which the document feeding device according to the second embodiment of the present invention is lifted up so as to be further inclined from the lift-down state. [Figure 14] 10 is a flowchart showing a control operation of the document feeder according to the second embodiment of the present invention. [Figure 15] 10A and 10B are a side view and a front view of a document feeding device according to a third embodiment of the present invention. [Figure 16] 10A and 10B are diagrams for explaining the operation of the document feeding device according to the third embodiment of the present invention. [Figure 17] 10A and 10B are diagrams for explaining the operation of the document feeding device according to the third embodiment of the present invention. [Figure 18] 10A and 10B are diagrams for explaining the operation of the document feeding device according to the third embodiment of the present invention. [Figure 19] 10A and 10B are a side view and a front view of a document feeding device according to a fourth embodiment of the present invention. [Figure 20] 10A and 10B are diagrams illustrating the operation of the document feeding device according to the fourth embodiment of the present invention. [Figure 21] 10A and 10B are diagrams illustrating the operation of the document feeding device according to the fourth embodiment of the present invention. [Figure 22] 10A and 10B are diagrams illustrating the operation of the document feeding device according to the fourth embodiment of the present invention. [Figure 23] 10A and 10B are diagrams showing the positional relationship between a rotating member and a cam at each position when the rotating member according to the fourth embodiment of the present invention moves. [Figure 24] 10 is a flowchart showing a control operation of the document feeder according to the fifth embodiment of the present invention. [Figure 25] FIG. 10 is a diagram showing a state in which the document feeder is in a lift-down state before being lifted up. [Figure 26] FIG. 10 is a diagram showing a state in which the document feeder is lifted up and in a lifted-up state. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below with reference to the accompanying drawings. In each drawing for explaining the present invention, components such as members and components having the same function or shape are designated by the same reference numerals as far as they can be distinguished, and once they have been described, their description will be omitted.

[0012] <Overall configuration of image forming apparatus> FIG. 1 is a diagram showing the overall configuration of an image forming apparatus according to a first embodiment of the present invention.

[0013] Here, the term "image forming apparatus" in this specification includes a printer, a copier, a facsimile, a printing machine, or a multifunction machine that combines two or more of these. In the following description, an electrophotographic image forming apparatus is used as an example, but the imaging method may be an inkjet method or other method in addition to the electrophotographic method. Furthermore, "image formation" in this specification refers not only to forming meaningful images such as characters and figures, but also to forming meaningless images such as patterns. First, the overall configuration of an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIG. 1.

[0014] As shown in FIG. 1, an image forming apparatus 100 according to the first embodiment of the present invention includes a document feeding device 1, an image reading unit 2, an image forming unit 3, and a sheet supply unit 4.

[0015] The document feeding device 1 is an example of a sheet feeding device that feeds sheets. Here, the sheet feeding device according to the present invention will be described using the document feeding device 1 as an example. The document feeding device 1 according to the first embodiment of the present invention includes a loading section 11 on which documents are placed, a separation feeding section 12 that separates and feeds the documents 10 one by one from the loading section 11, a correction section 13 that corrects skew of the fed documents 10, a transport section 14 that transports the corrected documents 10 to an image reading section 2, and a discharge section 15 to which the documents 10, whose images have been read by the image reading section 2, are discharged.

[0016] The image reading unit 2 includes a first image reading unit 21 that reads an image on the front side of the document 10, and a second image reading unit 22 that reads an image on the back side of the document 10. The first image reading unit 21 is disposed below the contact glass 20 and is configured to be able to move back and forth along the lower surface of the contact glass 20 in the direction of arrow X in FIG. 1. On the other hand, the second image reading unit 22 is disposed inside the document feeding device 1.

[0017] The image forming section 3 includes four imaging units 30Y, 30M, 30C, and 30K, an optical writing device 31, a transfer device 32, a timing roller pair 33, a fixing device , and a paper discharge roller pair .

[0018] The four imaging units 30Y, 30M, 30C, and 30K have the same configuration except that they contain developers of different colors, such as yellow, magenta, cyan, and black, which correspond to the color separation components of a color image. Specifically, each of the imaging units 30Y, 30M, 30C, and 30K includes a drum-shaped photoconductor 36 as an image carrier, a charging device 37 that charges the surface of the photoconductor 36, a developing device 38 that supplies toner as a developer to the surface of the photoconductor 36 to form a toner image, and a cleaning device 39 that cleans the surface of the photoconductor 36.

[0019] The transfer device 32 has an endless intermediate transfer belt 50 stretched by multiple rollers, four primary transfer rollers 51 that transfer the toner images on each photosensitive element 36 to the intermediate transfer belt 50, and a secondary transfer roller 52 that transfers the toner images transferred onto the intermediate transfer belt 50 to a sheet.

[0020] The sheet supply unit 4 includes a plurality of sheet storage units 40 that store sheets as recording media for forming images, and a sheet supplying means 41 that supplies sheets from each sheet storage unit 40 to the image forming unit 3. The sheets stored in the sheet storage units 40 may be paper, overhead projector sheets or fabric, metal sheets, plastic films, or prepreg sheets made of carbon fibers pre-impregnated with resin. In addition to plain paper, the paper includes cardboard, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, etc.

[0021] FIG. 2 is a side view of the image forming apparatus 100 according to the first embodiment of the present invention, as viewed from the left side in FIG.

[0022] 2, in image forming apparatus 100 according to the first embodiment of the present invention, document feeding device 1 is swingably attached via hinge mechanism 101 provided on the image forming apparatus main body. Therefore, document feeding device 1 is configured to be switchable between a lift-down state (state shown by solid lines in FIG. 2) in which it is placed on image reading unit 2, which is the base unit, and a lift-up state (state shown by two-dot chain lines in FIG. 2) in which it is lifted up from image reading unit 2 at an angle from the lift-down state. In the lift-up state in which document feeding device 1 is lifted up, document feeding device 1 retreats from above contact glass 20 of image reading unit 2, allowing a document to be placed on contact glass 20.

[0023] <Basic operations of image formation> Next, the basic operation of the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIG.

[0024] When originals 10 are set on the loading section 11 of the original feeding device 1, upon receiving an instruction to start a printing operation, the originals 10 are separated one by one from the loading section 11 and fed by the separation feeding section 12. Then, the originals 10 are corrected for skew in the correction section 13, and then conveyed to the first image reading section 21 by the conveying section 14. When the originals 10 are conveyed to the first image reading section 21, the image on the front side of the originals 10 is read by the first image reading section 21. In the case of single-sided image reading, after the image is read by the first image reading section 21, the originals 10 are discharged to the discharge section 15. In contrast, in the case of double-sided image reading, after the image on the front side of the originals 10 is read by the first image reading section 21, the image on the back side of the originals 10 is read by the second image reading section 22, and the originals 10 are discharged to the discharge section 15.

[0025] Furthermore, when the original 10 is set on the contact glass 20, the first image reading unit 21 moves back and forth in the direction of the arrow X in FIG. 1, and reads the image of the original 10 as the first image reading unit 21 moves.

[0026] When the image of the original 10 is read by the first image reading unit 21, or by the first image reading unit 21 and the second image reading unit 22, an image is formed in the image forming unit 3 based on the read image information. Specifically, first, the photoconductor 36 of each imaging unit 30Y, 30M, 30C, and 30K begins to rotate, and the surface of the photoconductor 36 is charged to a uniform high potential by the charging device 37. Next, the optical writing device 31 exposes the charged surface of each photoconductor 36 to light based on the image information of the read original 10. This reduces the potential of the exposed portion, and an electrostatic latent image is formed on each photoconductor 36. Then, toner is supplied from the developing device 38 to this electrostatic latent image, and a toner image of each color is formed on each photoconductor 36. The image information may be image information read by the image reading unit 2 or image information sent from a terminal device separate from the image forming apparatus.

[0027] Thereafter, the toner images on each photoconductor 36 reach the position of the primary transfer roller 51 (primary transfer nip) as each photoconductor 36 rotates, and are transferred to the intermediate transfer belt 50 at the primary transfer nip so that the toner images are sequentially superimposed on one another. After the toner images have been transferred to the intermediate transfer belt 50, a cleaning operation for each photoconductor 36 is performed by a cleaning device 39. This removes foreign matter such as residual toner from the surface of each photoconductor 36. Then, the toner images transferred onto the intermediate transfer belt 50 are transported to the position of the secondary transfer roller 52 (secondary transfer nip) as the intermediate transfer belt 50 rotates, and are transferred to a sheet.

[0028] At this time, the sheet transported to the secondary transfer nip is supplied from the sheet supply unit 4. The sheet is sent out from the sheet storage unit 40, stopped temporarily by the timing roller pair 33, and then transported in time with the toner image on the intermediate transfer belt 50 reaching the secondary transfer nip. In this way, a full-color toner image is transferred onto the sheet.

[0029] The image formed on the sheet is not limited to a full-color image formed using the four imaging units 30Y, 30M, 30C, and 30K, but may be a monochrome image formed using any one of the four imaging units 30Y, 30M, 30C, and 30K, or a two-color or three-color image formed using any two or three of the imaging units.

[0030] The sheet onto which the toner image has been transferred is transported to the fixing device 34. In the fixing device 34, the sheet passes between a pair of heated rotors, whereby the toner image on the sheet is heated and pressurized, and the toner image is fixed to the sheet. The sheet is then ejected to a sheet stack section or the like outside the device. This completes the series of image forming operations.

[0031] <Configuration of document feeder> FIG. 3 is a diagram showing a detailed configuration of the document feeding device 1 according to the first embodiment of the present invention.

[0032] The detailed configuration of the document feeding device 1 will be described below with reference to Fig. 3. In the following description, the downstream side in the document feeding direction and document transport direction will be simply referred to as "downstream", and the upstream side in the document feeding direction and document transport direction will be simply referred to as "upstream".

[0033] As shown in Figure 3, the loading section 11 of the document feeding device 1 is provided with a document tray 61 on which the document 10 is placed, a set filler 67 provided at the top end of the document tray 61, a document set sensor 72 that detects whether or not the document 10 has been placed on the document tray 61 by detecting the tip of the set filler 67, a home position sensor 73 that detects a state in which no document 10 has been placed on the document tray 61 as the home position, and a paper feed proper position sensor 74 that detects whether or not the downstream end of the document 10 on the document tray 61 is at an appropriate height.

[0034] The document tray 61 has a movable document tray 61A, at least a portion of which on the downstream side rotates around a support shaft 61C. A movable arm 160 that pushes up the movable document tray 61A is provided below the movable document tray 61A. The movable arm 160 is connected to a document tray motor 155 via a connecting shaft 161, and when the document tray motor 155 is driven, the tip of the movable arm 160 rises or falls. This allows the tip of the movable document tray 61A to be raised and lowered. In this way, the document tray motor 155, the movable arm 160, and the connecting shaft 161 function as a document tray drive mechanism that drives the document tray motor 155 to raise and lower the document tray 61A.

[0035] The document tray 61 is also provided with a pair of side guide plates 64 for positioning the document 10 in the width direction, which is a direction perpendicular to the feeding direction. The side guide plates 64 may be a pair that can move relatively close to and away from each other so that the centers of the document tray 61 and the document 10 in the width direction are aligned, or may be arranged so that one edge of the document 10 abuts against one edge of the document tray 61 and only the other edge is movable.

[0036] The document tray 61 is also provided with document length detection sensors 71A and 71B that determine the length of the document 10 in the feeding direction. The document length detection sensors 71A and 71B may be, for example, reflective sensors or actuator-type sensors that can detect even a single document. The document length detection sensors 71A and 71B are positioned so that they can determine whether the document is vertical or horizontal for at least the same document size.

[0037] The separation and feeding section 12 of the document feeder 1 is provided with a pickup roller 68 provided above the leading end of the movable document tray 61A, and a feed belt 69 and a reverse roller 70 arranged to face each other. The pickup roller 68 is an example of a feeding member that picks up and feeds several uppermost sheets of the documents 10 (a stack of documents) placed on the document tray 61. The pickup roller 68 is configured to be movable toward and away from the movable document tray 61A. The feed belt 69 and the reverse roller 70 cooperate to separate the documents 10 one by one. When the feed belt 69 rotates in the document feeding direction and multiple documents 10 are about to be fed in a double feed, the reverse roller 70 rotates in the direction opposite to the rotation of the feed belt 69, thereby separating the documents 10 and preventing double feed.

[0038] The correction unit 13 of the document feeder 1 includes a pull-out roller 81 as a correction member for correcting the skew of the fed document 10, a bump sensor 75 for determining the length of the document 10 in the transport direction, and a document width sensor 76 for determining the width of the document 10 perpendicular to the transport direction. The pull-out roller 81 has a leading edge alignment function that corrects the skew of the document 10 by being bumped by the leading edge of the fed document 10 and then pulls out the corrected document 10 for transport. The bump sensor 75 is disposed between the feed belt 69 and the pull-out roller 81. When the bump sensor 75 detects the leading and trailing edges of the document 10, the length of the document 10 in the transport direction is determined from motor pulses corresponding to the transport distance. The document width sensor 76 has multiple light-emitting elements arranged in the width direction of the document 10 downstream of the pull-out roller 81 and a light-receiving element disposed opposite the light-emitting elements. When the document 10 passes between the light-emitting elements and the light-receiving elements, the width of the document 10 is determined based on the detection result of the light-receiving element.

[0039] The transport section 14 of the document feeder 1 is provided with a plurality of transport roller pairs 82 to 84 as transport members for transporting the document 10. These transport roller pairs 82 to 84 are a reading entrance roller 82 arranged upstream of the first image reading section 21, a first reading exit roller 83 arranged between the first image reading section 21 and the second image reading section 22, and a second reading exit roller 84 arranged downstream of the second image reading section 22. The number and locations of the transport roller pairs arranged in the transport section 14 can be changed as desired depending on, for example, the path design of the document transport path and the minimum size of the document 10 that the document feeder 1 allows.

[0040] Furthermore, a reading roller 86 is provided in the conveying unit 14 so as to face the second image reading unit 22. The reading roller 86 suppresses floating of the original 10 in the second image reading unit 22, and also functions as a white reference unit for acquiring shading data in the second image reading unit 22.

[0041] In addition, a reading entrance sensor 77, a registration sensor 78, and a paper discharge sensor 79 are arranged in this order from upstream to downstream in the conveying unit 14. More specifically, the reading entrance sensor 77 is arranged between the pull-out roller 81 and the reading entrance roller 82, downstream of the document width sensor 76. In addition, the registration sensor 78 is arranged between the reading entrance roller 82 and the first image reading unit 21. The paper discharge sensor 79 is arranged between the first reading exit roller 83 and the second reading exit roller 84. These sensors 77, 78, and 79 are used for conveyance control such as the conveyance distance or conveyance speed of the document 10, as well as for jam detection.

[0042] The discharge section 15 of the document feeder 1 is provided with a discharge tray 63 onto which the document 10 is discharged after the image has been read, and a discharge roller 85 disposed downstream of the second reading exit roller 84. The document 10 from which the image has been read is discharged onto the discharge tray 63 by the discharge roller 85.

[0043] FIG. 4 is a block diagram of a control system of the document feeder 1 according to the first embodiment of the present invention.

[0044] 4, the document feeder 1 includes a pickup motor 151 that moves the pickup roller 68 toward or away from the movable document tray 61A, a paper feed motor 152 that rotates the pickup roller 68 and the feed belt 69, a reading motor 153 that drives the reading entrance roller 82, the first reading exit roller 83, and the second reading exit roller 84, a paper discharge motor 154 that drives the paper discharge roller 85, a document tray motor 155 that drives the movable document tray 61A, and a controller 150 that controls the series of operations. The controller 150 is connected to a main body control unit 120 that performs overall control of the image forming apparatus 100 via an I / F 110. The main body control unit 120 is also connected to an operation unit 130, through which a user performs various operations, via an I / F 111.

[0045] <Original feeding operation> Next, the document feeding operation in the document feeding device 1 will be described with reference to FIGS.

[0046] 3, when the originals 10 (stack of originals) are placed on the original tray 61, the set filler 67 and the original set sensor 72 detect that the originals 10 have been set, and information indicating that the originals 10 have been set is transmitted from the controller 150 to the main body control unit 120 via the I / F 110. In addition, when the originals 10 are placed on the original tray 61, the length of the originals 10 in the feeding direction is determined by the original length detection sensors 71A and 71B.

[0047] When the set filler 67 and the document set sensor 72 detect that the document 10 has been set on the document tray 61, the controller 150 rotates the document tray motor 155 in the forward direction to raise the leading edge of the movable document tray 61A so that the top surface of the document 10 (document stack) comes into contact with the pickup roller 68. At this time, the pickup roller 68 is pushed up by the document 10 on the movable document tray 61A. In addition, the proper paper feed position sensor 74 detects whether the downstream edge of the document 10 on the document tray 61 is at an appropriate height.

[0048] Thereafter, when the user presses the print key on the operation unit 130 and a document feed signal is sent from the main body control unit 120 to the controller 150 via the I / F 110, the pickup roller 68 is rotated by the forward rotation of the paper feed motor 152, and several sheets of the document 10 (ideally one sheet) on the document tray 61 are fed.

[0049] When the topmost document 10 is fed by the pickup roller 68, the feed belt 69 is rotated in the feed direction by the forward rotation of the feed motor 152. Furthermore, the reverse roller 70 is rotated in the opposite direction to the feed direction, separating the topmost document 10 from the documents below it, and feeding only the topmost document 10. When the reverse roller 70 is in direct contact with the feed belt 69 or when it is in contact with the feed belt 69 with one document sandwiched therebetween, the reverse roller 70 rotates in conjunction with the rotation of the feed belt 69. However, when two or more documents are interposed between the feed belt 69 and the reverse roller 70, the accompanying rotation force becomes lower than the torque of a preset torque limiter, and the reverse roller 70 rotates in the opposite direction to the rotation of the feed belt 69. This pushes back any excess documents, preventing double feeding of documents.

[0050] The document 10, separated by the action of the feed belt 69 and the reverse roller 70, is fed downstream by the feed belt 69, and after its leading edge is detected by the abutment sensor 75, it continues to move forward and abuts against the stopped pull-out roller 81. The document 10 is then fed a predetermined distance from the detection of the abutment sensor 75, and when the document 10 is pressed against the pull-out roller 81 with a predetermined amount of deflection, the feed motor 152 is stopped, thereby stopping the drive of the feed belt 69. At this time, the pickup motor 151 is rotated to raise the pickup roller 68 and move it away from the top surface of the document 10. As a result, the document 10 is fed only by the feeding force of the feed belt 69. The leading edge of the document 10 then enters the nip between the upper and lower roller pair of the pull-out roller 81, where the leading edge is aligned (skew corrected).

[0051] The pull-out rollers 81 align the leading edges of the documents 10 and transport the aligned documents 10 further downstream. The pull-out rollers 81 are driven by the reverse rotation of the paper feed motor 152. When the paper feed motor 152 rotates in the reverse direction, the pull-out rollers 81 are driven, but the pickup roller 68 and the feed belt 69 are not driven.

[0052] When the original 10 is transported by the pull-out rollers 81, the size of the original 10 in the width direction is detected by the original width sensor 76. Furthermore, the length of the original 10 in the transport direction is detected from the motor pulses by reading the leading and trailing ends of the original 10 by the abutment sensor 75.

[0053] Furthermore, when the original 10 is transported by the pull-out roller 81, the original transport speed at the position of the pull-out roller 81 is set to be faster than the original transport speed at the position of the first image reading unit 21, thereby shortening the processing time for sending the original 10 to the first image reading unit 21. When the leading edge of the original 10 is detected by the reading entrance sensor 77, before the leading edge of the original 10 enters the nip between the upper and lower rollers of the reading entrance roller 82, the controller 150 starts to decelerate the original transport speed to make it the same as the reading transport speed, and simultaneously drives the reading motor 153 in the forward direction to drive the reading entrance roller 82, the first reading exit roller 83, and the second reading exit roller 84. When the controller 150 detects the leading edge of the original 10 by the registration sensor 78, the controller 150 decelerates the transport speed of the original 10 over a predetermined transport distance, temporarily stops the original 10 just before the first image reading unit 21, and sends a stop signal to the main body control unit 120 via the I / F 110.

[0054] Subsequently, when a reading start signal is sent from the main body control unit 120 to the controller 150 via the I / F 110, the controller 150 accelerates the speed of the stopped original 10 so that the speed reaches a predetermined transport speed before the leading edge of the original reaches the position of the first image reading unit 21. At this time, the position of the leading edge of the original is detected by counting pulses of the reading motor 153, and at the timing when the leading edge of the original reaches the first image reading unit 21, a gate signal indicating the effective image area in the sub-scanning direction (the same direction as the transport direction of the original 10) on the front side of the original 10 is sent to the main body control unit 120. This gate signal is continuously sent until the trailing edge of the original leaves the first image reading unit 21. Then, while the original 10 is transported by the drive of the reading entrance rollers 82 and the first reading exit rollers 83, the image on the front side of the original 10 is read by the first image reading unit 21.

[0055] In the case of single-sided document reading, the document 10, after the image has been read by the first image reading unit 21, passes directly through the second image reading unit 22 and is conveyed to the paper discharge tray 63. At this time, when the leading edge of the document 10 is detected by the paper discharge sensor 79, the controller 150 drives the paper discharge motor 154 in the forward direction to rotate the paper discharge roller 85 in the counterclockwise direction in Fig. 3. Furthermore, based on the pulse count of the paper discharge motor 154 from the detection of the leading edge of the document 10 by the paper discharge sensor 79, the controller 150 controls the paper discharge motor drive speed to slow down just before the trailing edge of the document 10 leaves the nip between the upper and lower roller pairs of the paper discharge roller 85, so that the document 10 discharged onto the paper discharge tray 63 does not jump out.

[0056] On the other hand, in the case of double-sided document reading, the leading edge of the document is detected by the paper discharge sensor 79, and then the position of the leading edge of the document being conveyed is detected by counting pulses of the reading motor 153. At the timing when the leading edge of the document reaches the position of the second image reading unit 22, the controller 150 transmits a gate signal indicating the effective image area in the sub-scanning direction on the back side of the document 10 to the second image reading unit 22. This gate signal is continuously transmitted until the trailing edge of the document leaves the second image reading unit 22. Then, while the document 10 is conveyed by the drive of the first reading exit roller 83 and the second reading exit roller 84, the image on the back side of the document 10 is read by the second image reading unit 22 in a document flow-through reading method (sheet-through reading). Thereafter, the document 10 is discharged to the paper discharge tray 63 by the paper discharge rollers 85.

[0057] <Issues when lifting> Here, a problem that occurs when the document feeder 1 is lifted (lifted up) will be described.

[0058] Fig. 25 is a diagram showing a state in which the document feeding device 1 is in a lift-down state before being lifted up, while Fig. 26 is a diagram showing a state in which the document feeding device 1 has been lifted up and is in a lift-up state.

[0059] 25, when the document feeder 1 is in the lift-down state, preparation for the document feeding operation is started when the document 10 is placed on the document tray 61. That is, the document tray motor 155 is driven to raise the leading end of the movable document tray 61A. As a result, the document 10 on the movable document tray 61A is lifted, and the top surface of the document 10 comes into contact with the pickup roller 68. In this state, the document 10 is pressed and held by the movable document tray 61A and the pickup roller 68.

[0060] However, the pressure applied to the original 10 at this time is merely a pressure to hold the original 10 so that it can be fed, so if the original feeding device 1 is lifted from this state and enters a lifted-up state, there is a risk that the original 10 will fall from the original tray 61, as shown in Figure 26.

[0061] One way to prevent the document 10 from falling when the document is lifted up is to provide a separate member to hold down the document 10 on the document tray 61. However, if the document 10 is a small-sized sheet such as a business card, the pickup roller 68 that holds the document 10 covers the top surface of the document 10, which poses a problem in that it is not possible to secure space for a separate member to hold down the document 10. Furthermore, providing a separate member increases the complexity of the structure and increases manufacturing costs. Therefore, a preferred method for preventing the document 10 from falling when the document is lifted up is to prevent the document 10 from falling without providing a separate member to hold down the document 10.

[0062] Therefore, the present invention proposes an original feeding device that can prevent the original from falling when lifted up without providing a separate member. The following describes the characteristic features of the present invention, taking a first embodiment of the present invention as an example.

[0063] <Characteristics of the present invention> Fig. 5 is a front view of the document feeder 1 according to the first embodiment of the present invention, and Fig. 6 is a side view of the document feeder 1 according to the first embodiment of the present invention as seen from the left side in Fig. 5.

[0064] 6, the document feeder 1 is provided with a lift-up detection means 90 near the hinge mechanism 101 that detects whether the document feeder 1 has been lifted, i.e., whether the document feeder 1 has entered a lift-up state. The lift-up detection means 90 may be, for example, an optical sensor that detects the lift-up state of the document feeder 1 by switching from a light-blocking state to a light-transmitting state as the document feeder 1 is lifted up. The lift-up detection means 90 may be a contact sensor in addition to a non-contact sensor such as an optical sensor.

[0065] 5 or 6, the document feeder 1 is also provided with a pressure means 60 that applies pressure to the pickup roller 68. The pressure means 60 urges the pickup roller 68 downward, thereby pressing the pickup roller 68 toward the document tray 61.

[0066] Fig. 7 is a diagram showing the configuration of the pressure applying means 60 according to the first embodiment of the present invention. In detail, Fig. 7(a) is a diagram showing the state before the two springs 66, 67 constituting the pressure applying means 60 are assembled, and Figs. 7(b), (c), and (d) are diagrams showing the state in which the pressure applying means 60 is compressed by different amounts with the two springs 66, 67 assembled.

[0067] 7(a), the pressure applying means 60 has two springs 66, 67 which are different in length and diameter. Of the two springs 66, 67, the first spring 66 is longer and has a smaller diameter than the second spring 67. Conversely, the second spring 67 is shorter and has a larger diameter than the first spring 66.

[0068] The first spring 66 is assembled to a pressing member 93 that presses the pickup roller 68 or a holding member that holds the pickup roller 68. Specifically, in the example of FIG. 7 , a rod-shaped support portion 93a provided on the back surface of the pressing member 93 is inserted into the first spring 66, thereby assembling the first spring 66 to the pressing member 93. Meanwhile, the second spring 67 is assembled by being inserted into a cylindrical spring guide 94a provided in a housing portion 94 of the document feeder 1. Furthermore, by inserting the first spring 66 into the second spring 67, the two springs 66, 67 are assembled to form the pressure means 60. In this state, the two springs 66, 67 are elastically deformable independently of each other, and the pressing member 93 is held so as to be displaceable in the vertical direction as the two springs 66, 67 expand and contract.

[0069] When the pressure applying means 60 having such a configuration is compressed by a relatively small amount, as shown in FIG. 7(b) or (c), only the longer first spring 66 of the two springs 66, 67 is compressed. Therefore, in this case, a pressure force (repulsion force) corresponding to the compression amount of the first spring 66 is generated. In contrast, when the pressure applying means 60 is compressed by a large amount, as shown in FIG. 7(d), not only the first spring 66 but also the second spring 67 is compressed, and a large pressure force (repulsion force) corresponding to the compression amount of the two springs 66, 67 is generated. As described above, in the first embodiment of the present invention, the pressure applying means 60 is configured using two springs 66, 67 having different lengths and diameters, and therefore the pressure force (repulsion force) can be changed more greatly than when the pressure applying means 60 is configured using a single spring.

[0070] <Pressing operation of pressing means> Next, the pressing operation of the pressing means 60 according to the first embodiment of the present invention will be described.

[0071] First, as shown in FIG. 8, when the document feeder 1 is in the lift-down state, if a document 10 is set on the document tray 61, the set filler 67 and the document set sensor 72 detect the setting of the document 10, and the document tray motor 155 is driven to raise the tip of the movable document tray 61A.

[0072] As a result, the original 10 on the movable original tray 61A is raised to a height that allows it to be fed, as shown in Figure 9. At this time, the top surface of the original 10 is pressed against the pickup roller 68, causing the pickup roller 68 to rise, and the pressure means 60 is slightly compressed as shown in Figure 7(b). Therefore, in this state, the pickup roller 68 is pressed downward by the pressure means 60, and the original 10 is pressed by the pickup roller 68 and the movable original tray 61A in a state that allows it to be fed.

[0073] Thereafter, when an instruction to start feeding is given, pickup roller 68 starts to rotate, and documents 10 are separated and fed one by one from document tray 61. When the first (top) document 10 has been fed, pickup motor 151 drives pickup roller 68 to rise and retract so as not to come into contact with the top surface of second document 10 in order to prevent double feeding of the second document 10. As pickup roller 68 rises at this time, pressure means 60 becomes slightly more compressed as shown in Figure 7(c), but because pickup roller 68 retracts to a position where it does not come into contact with document 10, no pressure is applied to document 10.

[0074] Here, when the document feeder 1 is lifted and switched to the lift-up state as indicated by the two-dot chain line in Fig. 2, the lift-up operation of the document feeder 1 is detected by the lift-up detection means 90 in Fig. 6. Then, based on the detection signal from the lift-up detection means 90, the controller 150 (see Fig. 4) rotates the document tray motor 155 in the forward direction, and further raises the leading end of the movable document tray 61A as shown in Fig. 10. As a result, the pickup roller 68 is further pushed up by the lifted document 10, and the pressure means 60 is greatly compressed as shown in Fig. 7(d). At this time, both the first spring 66 and the second spring 67 are compressed, and a large pressure force is applied to the document 10.

[0075] As described above, in the first embodiment of the present invention, when the document feeder 1 is lifted and switched to the lift-up state, the movable document tray 61A further rises, which causes the pressure means 60 to compress significantly, thereby generating a large pressure force. That is, according to the first embodiment of the present invention, the movable document tray 61A is moved even closer to the pickup roller 68 based on detection information obtained when the lift-up detection means 90 detects that the document feeder 1 is in the lift-up state. This makes it possible to increase the pressure force on the document 10 sandwiched between the document tray 61A and the pickup roller 68 when the document feeder 1 is in the lift-up state, compared to the pressure force on the document 10 sandwiched between the document tray 61A and the pickup roller 68 when the document feeder 1 is in the lift-down state and ready to feed documents. This ensures that a sufficient pressure force is applied to the document 10 when it is lifted up, making it possible to more reliably prevent the document 10 from falling.

[0076] After the document feeder 1 is returned from the lifted-up state to the lifted-down state, the document tray motor 155 is reversed, causing the movable document tray 61A to descend, and the pressure on the document 10 by the movable document tray 61A and the pickup roller 68 is returned to the original pressure, i.e., the pressure when the document can be fed.

[0077] Next, another embodiment of the present invention will be described. In the following description, differences from the first embodiment of the present invention will be mainly described, and descriptions of the same parts will be omitted as appropriate.

[0078] <Second embodiment of the present invention> FIG. 11 is a side view of the document feeding device 1 according to the second embodiment of the present invention.

[0079] As shown in FIG. 11, in the second embodiment of the present invention, the document feeding device 1 includes two detection means, a first detection means 91 and a second detection means 92, as the lift-up detection means 90.

[0080] The first detection means 91 is a sensor that detects a first lifted-up state in which the document feeder 1 is lifted up from the lifted-down state so as to be inclined at a predetermined angle θ1, as shown in Fig. 12. The first detection means 91 has the same function as the lifted-up detection means 90 in the first embodiment. That is, when the first detection means 91 detects the first lifted-up state, the movable document tray 61A starts to rise in order to prevent the documents 10 from falling.

[0081] In contrast, the second detection means 92 is a sensor that detects a second lifted-up state in which the document feeder 1 is lifted at a larger angle θ2 from the lifted-down state than when it is in the first lifted-up state, as shown in Figure 13. The second detection means 92 functions as an interlock switch that cuts off the power supply to the document feeder 1.

[0082] For example, a transmission type optical sensor configured to have different detection ranges using light blocking members of different lengths can be used as the first detection means 91 and the second detection means 92. Note that these detection means 91 and 92 may be contact type sensors as well as non-contact type sensors.

[0083] FIG. 14 is a flowchart showing the control operation of the document feeder 1 according to the second embodiment of the present invention.

[0084] 14, when the control of the document feeder 1 is started and the set filler 67 and the document set sensor 72 detect that the document 10 has been set on the document tray 61 (if "YES" in Step 1), the movable document tray 61A is raised to a height at which the document can be fed, and the document feeder 1 transitions to a state where the document can be fed (Step 2). On the other hand, when the setting of the document 10 has not been detected (if "NO" in Step 1), the document feeder 1 remains in a standby state (Step 3).

[0085] Furthermore, when the document feeder 1 is lifted with the document 10 set therein and the first detection means 91 detects that the document feeder 1 is in the first lift-up state ("YES" in Step 4), the movable document tray 61A is further raised, and the pressure on the document 10 sandwiched between the movable document tray 61A and the pickup roller 68 is increased (Step 5). This prevents the document 10 from falling when it is lifted up. On the other hand, when the document feeder 1 is set therein and the user presses the print key on the operation unit 130 without lifting it ("NO" in Step 4), feeding of the document 10 is started, and image reading by the image reading unit 2 is started (Step 7). On the other hand, when the user does not press the print key ("NO" in Step 6), the document feeder 1 transitions to a standby state (Step 8).

[0086] Furthermore, if document feeder 1 is lifted and the first detection means 91 detects that document feeder 1 is in the first lifted-up state, and then the second detection means 92 detects that document feeder 1 is in the second lifted-up state (if "YES" in Step 9), power supply to document feeder 1 is cut off (Step 10). In this case, power supply to document tray motor 155 is also cut off, so that the operation of lifting movable document tray 61A to approach pickup roller 68 is not performed. On the other hand, if the second detection means 92 has not detected that document feeder 1 is in the second lifted-up state (if "NO" in Step 9), document feeder 1 remains in a standby state until detection is performed by second detection means 92 (Step 11).

[0087] As described above, in the second embodiment of the present invention, when the second detection means 92 detects that the document feeding device 1 is in the second lifted-up state, the power supply to the document feeding device 1 is cut off, thereby preventing malfunction of the document feeding device 1 after it is lifted up. Also, by preventing malfunction of the document feeding device 1, safety is improved.

[0088] In the second embodiment of the present invention, when the power supply to the document feeder 1 is cut off, the power supply to the document tray motor 155 is also cut off, and therefore the power supply for maintaining the elevated position of the movable document tray 61A is also cut off. For this reason, in the second embodiment of the present invention, the movable document tray 61A is configured using a geared motor with a self-locking function. As a result, even if the power supply to the document tray motor 155 is cut off and the power supply for maintaining the elevated position of the movable document tray 61A is no longer available, the descent of the movable document tray 61A (driving in a direction away from the pickup roller 68) can be prevented, and the pressure on the document 10 can be maintained. Therefore, even after the power supply is cut off, it is possible to effectively prevent the document 10 from falling.

[0089] Third Embodiment of the Present Invention Next, FIGS. 15(a) and 15(b) are a side view and a front view of an original feeding device 1 according to a third embodiment of the present invention.

[0090] As shown in Figures 15(a) and (b), the document feeding device 1 according to the third embodiment of the present invention includes a wire member 102 as an interlocking member that is interlocked with the switching operation in which the document feeding device 1 is switched between a lift-up state and a lift-down state, and a driving force transmission mechanism 140 that transmits the driving force of the wire member 102 to a movable arm 160, which is the mounting section driving mechanism 62.

[0091] One end of the wire member 102 is fixed to the image reading unit 2, which is the base, and the other end is fixed to the document feeding device 1 via a spring 115. The wire member 102 is also supported by a plurality of guide rollers 116 provided within the document feeding device 1.

[0092] The driving force transmission mechanism 140 includes a rack member 141 having a plurality of teeth 141a arranged in a straight line, and a clutch mechanism 142 that transmits rotation in only one direction. The rack member 141 is provided on the wire member 102 and is configured to be movable together with the wire member 102. The clutch mechanism 142 has a gear that meshes with the teeth of the transmission gear 143. In addition, the clutch mechanism 142 is connected to a connecting shaft 161 provided on the movable arm 160 so as to be able to transmit rotation in only one direction.

[0093] The operation of the document feeder 1 according to the third embodiment of the present invention will be described.

[0094] First, when the document feeder 1 is lifted slightly from the non-lifted up state (lifted down state) as shown in Figures 15(a) and (b) to the state shown in Figures 16(a) and (b), the document feeder 1 moves away from the top surface of the image reading unit 2, pulling the wire member 102 and causing the rack member 141 to move to the left in Figure 16(b).

[0095] 17(a) and 17(b), when the document feeder 1 is further lifted, the teeth 141a of the rack member 141 mesh with the gear of the clutch mechanism 142, and the linear motion of the rack member 141 causes the clutch mechanism 142 to rotate clockwise in FIG. 17(b). The rotation of the clutch mechanism 142 at this time is transmitted from the clutch mechanism 142 to the connecting shaft 161. This causes the connecting shaft 161 to rotate, driving the tip of the movable arm 160 to rise. When the tip of the movable document tray 61A rises to approach the pickup roller 68 due to the driving of the movable arm 160, the pressure on the document 10 sandwiched between the movable document tray 61A and the pickup roller 68 increases. This prevents the document 10 from falling when lifted up. Note that the rotation of the clutch mechanism 142 at this time is not transmitted to the document tray motor 155, so that the rotation of the clutch mechanism 142 does not place an unnecessary load on the document tray motor 155.

[0096] 18(a) and 18(b), when the document feeder 1 is further lifted and tilted to a large extent, the teeth 141a of the rack member 141 pass through the clutch mechanism 142, thereby disengaging the rack member 141 from the clutch mechanism 142. This stops the transmission of the driving force to the movable arm 160 due to the pulling of the wire member 102, and stops the upward movement of the movable document tray 61A. In addition, in this state, the movable arm 160 is held in position by the self-locking mechanism of the document tray motor 155. That is, because the movable arm 160 is connected to the document tray motor 155 via the clutch mechanism 142, the self-locking function of the document tray motor 155 prevents the movable arm 160 from descending even when the driving force in the upward direction is not transmitted. Therefore, the pressure on the document 10 by the movable document tray 61A and the pickup roller 68 is also maintained.

[0097] Furthermore, when document feeder 1 returns from the lifted-up state to the lifted-down state, the force pulling wire member 102 is relaxed in conjunction with the lift-down operation of document feeder 1, so that wire member 102 is pulled in the opposite direction by spring 115, and rack member 141 moves in the opposite direction from the direction of movement during lift-up. At this time, teeth 141a of rack member 141 pass through clutch mechanism 142 again, but the rotation caused by the engagement between rack member 141 and clutch mechanism 142 at this time is not transmitted to movable arm 160. Therefore, movable arm 160 does not descend in conjunction with the lift-down operation, and the leading end position of movable document tray 61A is maintained at the position after it was raised. Therefore, the pressure on documents 10 does not decrease during the lift-down operation, and documents 10 are effectively prevented from falling until the lift-down operation is completed.

[0098] Thereafter, when the lift-down operation of document feeder 1 is completed, document tray motor 155 is driven to rotate, causing the tip of movable document tray 61A to descend, and the pressure applied to document 10 is returned to the pressure applied when document feed is possible. At this time, the driving force of document tray motor 155 is not transmitted to movable arm 160 by clutch mechanism 142. However, when document tray motor 155 is driven to rotate in a direction to descend movable document tray 61A, the locked state of clutch mechanism 142 is released, allowing movable arm 160 to descend by gravity. As a result, the tip of movable document tray 61A descends, and the pressure applied to document 10 is returned to the pressure applied when document feed is possible.

[0099] On the other hand, the rotational drive of document tray motor 155 in the direction in which the tip of movable document tray 61A rises is transmitted to movable arm 160 via clutch mechanism 142. Therefore, after lifting down, movable document tray 61A can be raised and lowered by driving document tray motor 155. Furthermore, after lifting down, rack member 141 retreats to a position where it does not engage with clutch mechanism 142 (see FIG. 15(b)). Therefore, the drive of document tray motor 155 is not hindered by the engagement of rack member 141 with clutch mechanism 142.

[0100] As described above, in the third embodiment of the present invention, the leading edge of the movable document tray 61A can be raised in conjunction with the operation of lifting up the document feeder 1, so that even without the supply of power to drive the movable document tray 61A, sufficient pressure can be obtained to hold the document 10. Furthermore, because the leading edge of the movable document tray 61A can be raised even without the supply of power, the configuration according to the third embodiment of the present invention is preferable to the configuration in which the power supply to the document feeder 1 is cut off when the document feeder 1 is lifted up, such as the second embodiment of the present invention.

[0101] <Fourth embodiment of the present invention> 19(a) and 19(b) are a side view and a front view of an original feeding device 1 according to a fourth embodiment of the present invention.

[0102] 19(a) and 19(b), the document feeder 1 includes a rotating member 103 that rotates along a cam 117, instead of the wire member 102 as described above, as an interlocking member that interlocks with the switching operation of the document feeder 1. Also, in the fourth embodiment of the present invention, the configuration of the driving force transmission mechanism 140 that transmits driving force to the movable arm 160 is different from that in the third embodiment of the present invention.

[0103] Specifically, the driving force transmission mechanism 140 according to the fourth embodiment of the present invention includes a first pulley 144, a second pulley 145, a first timing belt 146 wound around the first pulley 144 and the second pulley 145, a second timing belt 147 wound around the second pulley 145 and the clutch mechanism 142, and a bevel gear 148. The bevel gear 148 is connected to the rotating member 103 as an interlocking member so as to rotate integrally with the rotating member 103. Other than that, the configuration is basically the same as that according to the third embodiment of the present invention.

[0104] The operation of the document feeder 1 according to the fourth embodiment of the present invention will be described.

[0105] First, when the document feeder 1 is lifted slightly from a non-lifted state (lift-down state) as shown in FIGS. 19(a) and 19(b) to a state as shown in FIGS. 20(a) and 20(b), the rotation member 103 comes into contact with the cam 117 and starts rotating as the document feeder 1 is lifted up. The rotation of the rotation member 103 is then changed in direction by the bevel gear 148 and transmitted to the first pulley 144. The rotation is then transmitted from the first pulley 144 to the second pulley 145 via the first timing belt 146, and further transmitted from the second pulley 145 to the clutch mechanism 142 via the second timing belt 147, causing the clutch mechanism 142 to rotate clockwise in FIG. 20(b). The rotation at this time is also transmitted from the clutch mechanism 142 to the connecting shaft 161, causing the connecting shaft 161 to rotate, and the movable arm 160 starts to move upward. Incidentally, the rotation of the clutch mechanism 142 during lift-up is not transmitted to the document tray motor 155, as in the third embodiment of the present invention, so that unnecessary load on the document tray motor 155 is avoided.

[0106] 21(a) and 21(b), when the document feeder 1 is further lifted, the rotating member 103 continues to rotate along the cam 117, and the rotation of the rotating member 103 is transmitted to the connecting shaft 161 via the clutch mechanism 142 by the same mechanism as above. This drives the tip of the movable arm 160 to move further upward. Then, as the tip of the movable arm 160 moves upward, the tip of the movable document tray 61A is pushed up so as to approach the pickup roller 68, and the pressure on the document 10 sandwiched between the movable document tray 61A and the pickup roller 68 increases. This prevents the document 10 from falling when it is lifted up.

[0107] 22(a) and 22(b), when the document feeder 1 is further lifted and tilted to a large extent, the rotary member 103 passes the cam 117, and the rotary member 103 is released from contact with the cam 117. This stops the transmission of the driving force to the movable arm 160 due to the rotation of the rotary member 103, and stops the lifting of the movable document tray 61A. In addition, in this state, the movable arm 160 is held in position by the self-locking mechanism of the document tray motor 155, so the pressure force on the document 10 is maintained, as in the third embodiment of the present invention.

[0108] Furthermore, when document feeder 1 is returned from the lifted-up state to the lifted-down state, rotating member 103 again contacts cam 117 in conjunction with the lift-down operation of document feeder 1, causing rotating member 103 to rotate in the opposite direction to the rotation direction during lift-up. The rotation of rotating member 103 at this time is also transmitted to clutch mechanism 142 via bevel gear 148, pulleys 144 and 145, and timing belts 146 and 147, but is not transmitted from clutch mechanism 142 to movable arm 160. Therefore, movable arm 160 does not descend in conjunction with the lift-down operation, and the leading end position of movable document tray 61A is maintained at the position after it was raised. Therefore, the pressure on document 10 does not decrease during the lift-down operation, and the pressure on document 10 is maintained at a high level until the lift-down operation is completed.

[0109] After that, when the lift-down operation of the document feeding device 1 is completed, the pressure on the document 10 is returned to the pressure when the document can be fed. However, the downward movement of the movable document tray 61A at this time and the upward and downward movement of the movable document tray 61A after the lift-down are the same as those in the third embodiment of the present invention, so explanations thereof will be omitted.

[0110] As described above, in the fourth embodiment of the present invention, as in the third embodiment of the present invention, the leading edge of movable document tray 61A can be raised in conjunction with the operation of lifting up document feeder 1, so that sufficient pressure to hold document 10 can be obtained even without power supply to drive movable document tray 61A. Furthermore, because the leading edge of movable document tray 61A can be raised even without power supply, the configuration of the fourth embodiment of the present invention is also suitable for a configuration in which power supply to document feeder 1 is cut off when the document feeder 1 is lifted up, such as in the second embodiment of the present invention.

[0111] FIG. 23 is a diagram showing the positional relationship between the rotary member 103 and the cam 117 at each position when the rotary member 103 according to the fourth embodiment of the present invention moves.

[0112] As shown in FIG. 23 , in the fourth embodiment of the present invention, when document feeder 1 is switched from the lift-down state before being lifted up to the lift-up state, rotating member 103 moves in the order of (a) → (b) → (c) → (d) in FIG. 23 in accordance with the switching operation of document feeder 1. Here, at position (a), the outer diameter portion of cam 117 is missing, so that rotating member 103 is not in contact with cam 117. Also, at position (d), there is a gap between rotating member 103 and cam 117, so that rotating member 103 is not in contact with cam 117. Therefore, at position (a) before being lifted up and position (d) after being lifted up, rotating member 103 does not rotate, and the rotation is not transmitted to movable arm 160 via clutch mechanism 142. On the other hand, between position (b) and position (c), rotating member 103 comes into contact with cam 117, so that the rotation is transmitted to movable arm 160, and the leading end of movable document tray 61A is driven to rise.

[0113] In this way, by preventing rotating member 103 from rotating between the position before lift-up and the position after lift-up, unnecessary transmission of drive force to movable arm 160 is prevented. Furthermore, by arranging rotating member 103 so as not to come into contact with cam 117 at the position (a) before lift-up (lift-down state), the drive of document tray motor 155 is not hindered by contact between rotating member 103 and cam 117 when document tray motor 155 normally raises the leading edge of movable document tray 61A to a state where documents can be fed.

[0114] Fifth embodiment of the present invention FIG. 24 is a flowchart showing the control operation of the document feeder 1 according to the fifth embodiment of the present invention.

[0115] In the fifth embodiment of the present invention, as in the above-mentioned embodiments, the pressure applied to the document 10 is increased when the document 10 is lifted up to prevent the document 10 from falling, and in addition, if the user attempts to lift up the document feeding device 1 with the document 10 set in place, a notification is given.

[0116] In detail, as shown in FIG. 24, when the set filler 67 and the document set sensor 72 detect that the document 10 has been set on the document tray 61 (if "YES" in Step 21), and the contact detection unit detects that the user's hand has touched the handle of the document feeding device 1 (if "YES" in Step 22), the notification means notifies the user by known means such as sound, light, or display on the operation screen based on the detection information from the contact detection unit (Step 23).

[0117] On the other hand, if the contact detection unit does not detect contact with the handle (if "NO" in Step 22), the user then presses the print key on the operation unit 130 (if "YES" in Step 24), which starts feeding the original 10 and starts reading the image by the image reading unit 2 (Step 25).

[0118] As described above, in the fifth embodiment of the present invention, when the user touches the handle of the document feeder 1 with the document 10 set on the document tray 61, the notification means notifies the user, allowing the user to recognize that an attempt has been made to lift up the document feeder 1 with the document 10 set therein. This makes it possible to prevent the document 10 from falling when the document feeder 1 is lifted up with the document 10 set therein.

[0119] 24, even if a notification is given by the notification means, if the user subsequently performs the lift-up operation of the document feeder 1, the operation of lifting the tip of the movable document tray 61A and increasing the pressure on the document 10 is performed, as in the above-described embodiments. Therefore, even if the document feeder 1 is lifted up with the document 10 set therein, the document 10 can be prevented from falling.

[0120] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the gist of the invention.

[0121] In the above embodiment, the present invention has been described as being applied to a document feeder that feeds documents, but the present invention can also be applied to a sheet feeder that feeds sheets other than documents. By applying the present invention to such a sheet feeder, it is possible to effectively prevent sheets from falling when the sheet feeder is lifted up.

[0122] To summarize the above-described aspects of the present invention, the present invention includes at least the following aspects.

[0123] [First aspect] The first aspect is a sheet feeding device comprising a loading section for loading a sheet, a feeding member for feeding the sheet from the loading section, and a pressure means for sandwiching and pressurizing the sheet between the loading section and the feeding member, wherein the sheet feeding device is configured to be switchable between a lift-down state in which the sheet is placed on a base section in a state in which it can be fed, and a lift-up state in which it is lifted up from the base section so as to be inclined from the lift-down state, and the pressure force of the sheet sandwiched between the loading section and the feeding member when the sheet feeding device is in the lift-up state is greater than the pressure force of the sheet sandwiched between the loading section and the feeding member when the sheet feeding device is in the lift-down state and in a state in which it can feed the sheet.

[0124] [Second aspect] The second aspect is the first aspect, further comprising a placement section drive mechanism that moves the placement section closer to or further away from the feeding member, and a lift-up detection means that detects that the sheet feeding device has switched from the lift-down state to the lift-up state, and the placement section drive mechanism moves the placement section closer to the feeding member than when it is in the feeding-enabled state, based on detection information when the lift-up detection means detects the lift-up state of the sheet feeding device.

[0125] [Third aspect] In a third aspect, in the second aspect, the lift-up detection means includes a first detection means for detecting a first lift-up state in which the sheet feeding device is lifted so as to be inclined at a predetermined angle from the lift-down state, and a second detection means for detecting a second lift-up state in which the sheet feeding device is lifted so as to be inclined at a larger angle from the lift-down state than when in the first lift-up state, and based on the detection information of the first detection means, performs an operation of moving the placement section closer to the feeding member, and based on the detection information of the second detection means, cuts off the power supply to the placement section drive mechanism to prevent the placement section from moving closer to the feeding member.

[0126] [Fourth aspect] In a fourth aspect, in the third aspect, the mounting section drive mechanism has a self-locking function that prevents the mounting section from being driven in a direction away from the feeding member when the power supply is cut off.

[0127] [Fifth aspect] The fifth aspect is the first aspect, further comprising a placement section drive mechanism that moves the placement section closer to or farther away from the feeding member, a linkage member that links with the switching operation when the sheet feeding device is switched to the lift-down state and the lift-up state, and a drive force transmission mechanism that transmits the drive force of the linkage member to the placement section drive mechanism, wherein the drive force transmission mechanism transmits the drive force of the linkage member that links with the switching operation when the sheet feeding device is switched to the lift-up state to the placement section drive mechanism, and the placement section drive mechanism moves the placement section closer to the feeding member.

[0128] [Sixth aspect] In a sixth aspect, in the fifth aspect, the drive force transmission mechanism has a clutch mechanism that transmits the drive force of the interlocking member, which is linked to the switching operation when the sheet feeding device is switched to the lift-up state, to the stacking section drive mechanism, but does not transmit the drive force of the interlocking member, which is linked to the switching operation when the sheet feeding device is switched to the lift-down state, to the stacking section drive mechanism.

[0129] [Seventh aspect] In a seventh aspect, in the fifth or sixth aspect, the interlocking member is a wire member that is pulled and returned in conjunction with the switching operation of the sheet feeding device between the lift-down state and the lift-up state.

[0130] [Eighth aspect] In the eighth aspect, in the fifth or sixth aspect, the interlocking member is a rotating member that rotates in one direction and the opposite direction in conjunction with the switching operation of the sheet feeding device between the lift-down state and the lift-up state.

[0131] [Ninth aspect] The ninth aspect is any one of the first to eighth aspects, in which a notification is given when the user touches a handle portion for switching the sheet feeding device to the lift-up state while the sheet is placed on the loading section.

[0132] [Tenth aspect] The tenth aspect is a document feeding device that feeds a document to an image reading section that reads an image of the document, and feeds the document using a sheet feeding device of any one of the first to ninth aspects.

[0133] [Eleventh aspect] An eleventh aspect is an image forming apparatus including the sheet feeding device according to any one of the first to ninth aspects or the document feeding device according to the tenth aspect. [Explanation of symbols]

[0134] 1 Document feeder (sheet feeder) 2 Image reading unit (base) 10 manuscripts (sheets) 11 Placement section 60 Pressurizing means 62 Mounting section drive mechanism 68 Pickup roller (feeding member) 90 Lift-up detection means 100 Image forming device 102 Wire member (interlocking member) 103 Rotating members (interlocking members) 140 Drive force transmission mechanism 142 Clutch mechanism [Prior art documents] [Patent documents]

[0135] [Patent Document 1] Japanese Patent Application Publication No. 11-237770

Claims

1. a placement section for placing a sheet; a feeding member that feeds the sheet from the stacking portion; a pressure applying means for applying pressure to the sheet by sandwiching the sheet between the placement portion and the feeding member; A sheet feeding device comprising: the sheet feeding device is configured to be switchable between a lift-down state in which the sheet feeding device is disposed on a base portion in a state in which the sheet can be fed, and a lift-up state in which the sheet feeding device is lifted up from the base portion so as to be inclined from the lift-down state, A sheet feeding device characterized in that the pressure applied to the sheet sandwiched between the stacking section and the feeding member when the sheet feeding device is in the lifted-up state is greater than the pressure applied to the sheet sandwiched between the stacking section and the feeding member when the sheet feeding device is in the lifted-down state and capable of feeding the sheet.

2. a mounting section drive mechanism that moves the mounting section toward or away from the feeding member; a lift-up detection unit that detects that the sheet feeding device has been switched from the lift-down state to the lift-up state; Equipped with The sheet feeding device according to claim 1, wherein the loading section drive mechanism moves the loading section closer to the feeding member than when the sheet is in the feeding-enabled state, based on detection information when the lift-up detection means detects the lift-up state of the sheet feeding device.

3. The lift-up detection means a first detection means for detecting a first lift-up state in which the sheet feeding device is lifted up so as to be inclined at a predetermined angle from the lift-down state; a second detection means for detecting a second lifted-up state in which the sheet feeding device is lifted up so as to be inclined at a larger angle from the lifted-down state than when the sheet feeding device is in the first lifted-up state; and based on the detection information of the first detection means, performing an approaching operation of the placement unit with respect to the feeding member; 3. The sheet feeding device according to claim 2, wherein the supply of power to the stacker drive mechanism is cut off based on the detection information of the second detection means, so that the stacker does not move toward the feed member.

4. 4. The sheet feeding device according to claim 3, wherein the mounting section drive mechanism has a self-locking function that prevents the mounting section from being driven in a direction away from the feeding member when power supply is cut off.

5. a mounting section drive mechanism that moves the mounting section toward or away from the feeding member; an interlocking member interlocked with a switching operation when the sheet feeding device is switched to the lift-down state and when the sheet feeding device is switched to the lift-up state; a driving force transmission mechanism that transmits the driving force of the interlocking member to the mounting section driving mechanism; Equipped with The sheet feeding device of claim 1, wherein the drive force transmission mechanism transmits the drive force of the interlocking member, which is interlocked with the switching operation when the sheet feeding device is switched to the lift-up state, to the stacking section drive mechanism, and the stacking section drive mechanism moves the stacking section closer to the feed member.

6. The sheet feeding device of claim 5, wherein the drive force transmission mechanism transmits the drive force of the interlocking member, which is linked to the switching operation when the sheet feeding device is switched to the lift-up state, to the stacking section drive mechanism, but has a clutch mechanism that does not transmit the drive force of the interlocking member, which is linked to the switching operation when the sheet feeding device is switched to the lift-down state, to the stacking section drive mechanism.

7. 6. The sheet feeding device according to claim 5, wherein the interlocking member is a wire member that is pulled and returned in association with the switching operation of the sheet feeding device between the lift-down state and the lift-up state.

8. 6. The sheet feeding device according to claim 5, wherein the interlocking member is a rotating member that rotates in one direction and in the opposite direction in association with switching between the lift-down state and the lift-up state of the sheet feeding device.

9. The sheet feeding device according to claim 1 , wherein a notification is given when a user touches a handle for switching the sheet feeding device to the lift-up state while the sheet is placed on the sheet placement section.

10. An original feeding device that feeds an original to an image reading unit that reads an image of the original, 2. An original feeding device, comprising: a sheet feeding device according to claim 1, for feeding the originals.

11. An image forming apparatus comprising the sheet feeding device according to claim 1.

Images