Image reading device, sheet skew prevention device, and image forming apparatus

Abstract

To provide an image reading device that, with a simple configuration, can correct inclination of a document, while conveying the document.SOLUTION: An image reading device such as an ADF 100 conveys a document such as a document Do to an image reading unit such as a first image reading unit 131 or a second image reading unit 135, and the image reading device has a plurality of inclination correction members such as inclination correction members 10 each provided with a rotation fulcrum inclined with respect to the conveyance direction, in a direction orthogonal to a conveyance direction such as a document conveyance direction X, on a conveyance path such as a conveyance path part BC that conveys a document after being separated into one to the next document conveying member such as a pull-out roller 123.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image reading device, a paper skew prevention device, and an image forming device. [Background technology]

[0002] In conventional image reading devices, a technique of providing a tilt correction means on the conveyance path to regulate the tilt of the document has been devised and is already known (see, for example, Patent Documents 1 to 3). Patent Document 1 discloses a configuration having width direction regulating means provided on a conveying path so as to be able to freely protrude and retract in order to prevent skew of the document.

[0003] Patent document 2 discloses a configuration in which a guide member is provided downstream of the pick-up roller in the document feed direction to guide the side of the document, in order to prevent the document from skewing when narrow and wide documents are mixed alternately.

[0004] Patent document 3 discloses a configuration having a skew correction member that moves in a direction perpendicular to the document transport direction to correct the skew of the document to a direction parallel to the transport direction, in order to prevent the document from skewing when narrow and wide documents are mixed alternately.

[0005] The conventional image reading device described above is similar to the present invention in that it corrects the skew of the document using a correction member, but the problem of the device configuration being complicated remains. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above-mentioned circumstances, and has an object to provide an image reading device that has a simple configuration and is capable of correcting the skew of a document while the document is being transported. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention is an image reading device that transports a document to an image reading unit, and has multiple tilt correction members, each with a rotation fulcrum inclined relative to the transport direction, on a transport path that transports the document after separation into individual sheets to the next document transport member, in a direction perpendicular to the transport direction. [Effects of the Invention]

[0008] According to the present invention, it is possible to correct the skew of a document while the document is being transported with a simple configuration. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating the configuration of a copying machine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a detailed configuration diagram of an ADF provided in the copying machine of FIG. [Figure 3] FIG. 3 is a block diagram of a control system of the ADF in FIG. 2. [Figure 4] FIG. 1 is a plan view showing a main configuration of a first embodiment. [Figure 5] FIG. 2 is an enlarged plan view showing the main configuration of the first embodiment. [Figure 6] FIG. 2 is an enlarged side view showing a main part of the first embodiment. [Figure 7] FIG. 2 is an enlarged side view showing the detailed configuration and operation of the first embodiment. [Figure 8] FIG. 10 is a plan view illustrating a second embodiment. [Figure 9] FIG. 10 is a plan view showing the main configuration of a third embodiment. [Figure 10] FIG. 10 is an enlarged side view showing the detailed configuration and operation of the third embodiment. [Figure 11] FIG. 10 is a plan view illustrating the operation of the third embodiment. [Figure 12] FIG. 10 is an enlarged side view showing the detailed configuration and operation of the third embodiment. [Figure 13] FIG. 10 is a plan view illustrating the operation of the third embodiment. [Figure 14] 10(a) to 10(c) are side views illustrating the operation process of the third embodiment. [Figure 15] FIG. 10 is a plan view showing the main configuration of the fourth embodiment. [Figure 16] FIG. 10 is an enlarged plan view showing a main part of Example 4. [Figure 17] FIG. 10 is an enlarged side view showing a main part of the fourth embodiment. [Figure 18] FIG. 10 is an enlarged side view showing the detailed configuration and operation of the fourth embodiment. [Figure 19] FIG. 10 is a plan view illustrating a fifth embodiment. [Figure 20] FIG. 13 is a plan view showing the main configuration of Example 6. [Figure 21] FIG. 13 is an enlarged side view showing the detailed configuration and operation of the sixth embodiment. [Figure 22] FIG. 10 is a plan view illustrating a sixth embodiment. [Figure 23] FIG. 13 is an enlarged side view showing the detailed configuration and operation of the sixth embodiment. [Figure 24] FIG. 13 is a plan view illustrating the operation of the sixth embodiment. [Figure 25] 10(a) to 10(c) are side views illustrating the operation process of the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Throughout the embodiments and examples, components (members and components) having the same function, shape, etc. will be designated by the same reference numerals once explained, and their explanation will be omitted unless there is a risk of confusion.

[0011] The schematic configuration of a copying machine 1 as an image forming apparatus according to an embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a schematic configuration diagram of a copying machine according to an embodiment of the present invention. As shown in Figure 1, the copying machine 1 includes an automatic document feeder (hereinafter also referred to as "ADF": Auto Document Feeder) 100 that functions as an image reading device, a paper feed unit 2, and an image forming unit 3.

[0012] The ADF 100 is disposed above the scanner unit 4 and is attached to the scanner unit 4 by a hinge so that it can be opened and closed in either a closed position where it overlaps the scanner unit 4 or an open position where it stands up from the scanner unit 4.

[0013] The ADF 100 is compatible with both a sheet-through reading method (automatic transport mode) and a fixed document reading method (pressure plate mode). In the sheet-through reading method, image information of a document D (see, for example, FIG. 2 described later) is read while the document is being transported by the ADF 100. In the fixed document reading method, the document to be read is placed on the contact glass 5 (see FIG. 2 described later) of the scanner unit 4, and the image is read while the first image reading unit 131 (see FIG. 2 described later) is moved along the contact glass 5.

[0014] The copying machine 1 has an operation panel that accepts user operations. By operating this operation panel, an operating mode can be arbitrarily set, such as an automatic feed mode (ADF mode) that reads documents using the sheet-through reading method described above, or a pressure plate mode that reads documents using the fixed document reading method described above.

[0015] The paper feed section 2 has paper feed cassettes 21, 22 that store paper such as recording paper of different paper feed sizes, a large-capacity paper feed tray 23 that stores a larger volume of recording paper than these paper feed cassettes 21, 22 and can transport it continuously, and paper feed means 24 consisting of various rollers that transport the paper stored in each paper feed cassette 21, 22 or the large-capacity paper feed tray 23 to the image formation position of the image forming section 3.

[0016] Image forming unit 3 includes exposure device 31, photosensitive drum 32, developing device 33, transfer belt 34, and fixing device 35. In image forming unit 3, based on image data of an original document read by an image reading unit inside ADF 100, exposure device 31 exposes photosensitive drum 32 to light to form a latent image on photosensitive drum 32, and developing device 33 supplies toner of different colors to photosensitive drum 32 for development. In image forming unit 3, transfer belt 34 transfers the image developed on photosensitive drum 32 onto paper fed from paper feed unit 2, and then fixing device 35 melts the toner of the toner image transferred onto the paper to fix the color image onto the paper.

[0017] The detailed configuration of an ADF 100 of the type having a second image reading unit provided in a copier will be described with reference to Figures 2 and 3. Figure 2 is a detailed configuration diagram of an ADF of the type having a second image reading unit provided in a copier, and Figure 3 is a block diagram of the control system of the ADF.

[0018] As shown in Figure 2, the ADF 100 is equipped with a document setting section A on which a stack of documents is set, a separation and feeding section B that separates and feeds each document sheet from the document stack set in the document setting section A, a registration section C that performs initial abutment alignment on the fed documents and pulls out and transports the aligned documents, a turn section D that turns the transported documents and transports the document surface toward the reading side (bottom in the figure) by the first image reading section 131, a first reading and transport section E that reads the front image of the document from below the contact glass by the first image reading section 131, a second reading and transport section F that reads the back image of the document by the second image reading section 135 after the front image has been read, a paper discharge section G that discharges the documents outside the machine after the front and back images have been read, and a stack section H that holds and stacks the discharged documents.

[0019] 3, the ADF 100 includes various motors 101 to 106 that drive the above-mentioned components, and a controller 150 that controls the series of operations of these motors. The controller 150 is connected via an I / F (interface) 108 to a main body control unit 90 that performs overall control of the copier 1. An operation unit 91 that allows a user to perform various operations is also connected to the main body control unit 90 via an I / F 107.

[0020] A stack of originals 110 to be read is set in the original setting unit A. The stack of originals 110 is set on an original table 112 including a movable original table 111. The stack of originals 110 is set on the original table 112 with the original surface facing upward. At this time, the width direction of the stack of originals 110 is positioned in a direction perpendicular to the conveyance direction by side guides (not shown). The setting of the stack of originals 110 is detected by a set filler 113 and a set sensor 114, and information indicating that the stack of originals 110 has been set is sent from the controller 150 to the main body control unit 90 via the I / F 108.

[0021] Furthermore, document length detection sensors 115 and 116 provided on document table 112 determine the approximate length of document stack 110 in the transport direction. Document length detection sensors 115 and 116 may be, for example, reflective sensors or actuator-type sensors capable of detecting even a single document. Document length detection sensors 115 and 116 must be positioned so that they can at least determine whether documents of the same size are vertical or horizontal.

[0022] Movable document table 111 is configured to be movable up and down in directions a and b in FIG. 2 by bottom plate lift motor 105. When document stack 110 is not set on document table 112, movable document table 111 is in a lowered state, and this state is detected by bottom plate HP sensor 117. When set feeler 113 and set sensor 114 detect that document stack 110 has been set on document table 112, controller 150 rotates bottom plate lift motor 105 forward to lift movable document table 111 so that the top surface of document stack 110 comes into contact with pickup roller 118 of separation feed unit B. Pickup roller 118 is moved in directions c and d in FIG. 2 by the action of a cam mechanism driven by pickup motor 101, and is also raised in direction c in FIG. 2 by being pushed by the upper surface of document stack 110 on movable document table 111 as movable document table 111 rises, so that pickup roller 118 can be detected by proper paper feed position sensor 119.

[0023] When a user presses the print key on operation unit 91 and a document feed signal is sent from main body control unit 90 to controller 150 via I / F 108, pickup roller 118 is rotated by the forward rotation of paper feed motor 102, and picks up several documents (ideally one document) on document table 112. The rotation direction of pickup roller 118 is the direction in which the top document on movable document table 111 is transported to the paper feed opening of paper feed belt 120.

[0024] The paper feed belt 120 is driven in the paper feed direction by the forward rotation of the paper feed motor 102. The reverse roller 121 is driven to rotate in the direction opposite to the paper feed direction by the forward rotation of the paper feed motor 102. This allows the topmost document picked up by the pickup roller 118 to be separated from the documents below it, so that only the topmost document can be fed. To explain in more detail, the reverse roller 121 contacts the paper feed belt 120 with a predetermined pressure, and when it is in contact with the paper feed belt 120 directly or through a single document, it rotates counterclockwise in response to the rotation of the paper feed belt 120. On the other hand, when two or more documents enter between the paper feed belt 120 and the reverse roller 121, the accompanying rotation force is set to be lower than the torque of the torque limiter, and the reverse roller 121 rotates in the clockwise direction, which is its original driving direction, and acts to push back the excess documents. This prevents double feeding of documents.

[0025] The document separated into a single sheet by the action of paper feed belt 120 and reverse roller 121 is sent by paper feed belt 120 toward registration section C, and after its leading edge is detected by abutment sensor 122, it continues to move forward and abuts against pull-out roller 123, which is stopped. The document is then sent a predetermined distance from the detection by abutment sensor 122, and when the document is pressed against pull-out roller 123 with a predetermined amount of deflection, paper feed motor 102 is stopped, thereby stopping the drive of paper feed belt 120. At this time, pickup motor 101 is rotated to retract pickup roller 118 from above the document, and the document is fed only by the conveying force of paper feed belt 120, so that the leading edge of the document enters the nip between the upper and lower roller pair of pull-out roller 123, and the leading edge is aligned (skew corrected).

[0026] Pull-out roller 123 has the skew correction function and is a roller for transporting the separated, skew-corrected document to intermediate roller 124, and is driven by the reverse rotation of paper feed motor 102. When paper feed motor 102 rotates reversely, pull-out roller 123 and intermediate roller 124 are driven, but pickup roller 118 and paper feed belt 120 are not driven.

[0027] 2, and detects the size of the document in the width direction perpendicular to the transport direction of the document transported by the pull-out rollers 123. The length of the document in the transport direction is detected from the motor pulses by reading the leading and trailing ends of the document with the abutment sensor 122.

[0028] When the document is transported from registration section C to turning section D by driving pull-out roller 123 and intermediate roller 124, the transport speed in registration section C is set to be faster than the transport speed in first reading transport section E, thereby shortening the processing time for sending the document to the image reading section. When the leading edge of the document is detected by reading entrance sensor 126, before the leading edge of the document enters the nip between the upper and lower roller pair of reading entrance rollers 127, the document transport speed begins to be decelerated to be the same as the reading transport speed, and at the same time, the reading motor 103 is driven in the forward direction to drive reading entrance roller 127, reading exit roller 128, and CIS (Contact Image Sensor) exit roller 129. When the leading edge of the document is detected by registration sensor 130, controller 150 decelerates the document transport speed over a predetermined transport distance, temporarily stops the document just before first image reading section 131, and sends a registration position stop signal to main body control section 90 via I / F 108.

[0029] Subsequently, when a reading start signal is sent from the main body control unit 90 to the controller 150 via the I / F 108, the controller 150 accelerates the speed of the original document stopped at the registration position so that the speed reaches a predetermined conveyance speed before the leading edge of the original document reaches the position of the first image reading unit 131. At this time, the position of the leading edge of the original document is detected by counting pulses of the reading motor 103, and at the timing when the leading edge of the original document reaches the first image reading unit 131, a gate signal indicating the effective image area of ​​the front surface of the original document in the sub-scanning direction (the same direction as the transport direction of the original document) is sent to the main body control unit 90. This gate signal is continuously sent until the trailing edge of the original document leaves the first image reading unit 131. Then, while the original document is transported by the drive of the reading entrance rollers 127 and the reading exit rollers 128, the image on the front surface of the original document is read by the first image reading unit 131.

[0030] In the case of single-sided document reading, the document, whose front side image has been read by first image reading unit 131 of first reading and conveying unit E, passes directly through second reading and conveying unit F and is conveyed to paper discharge unit G. At this time, when controller 150 detects the leading edge of the document with paper discharge sensor 132, controller 150 drives paper discharge motor 104 in the forward direction to rotate paper discharge roller 133 in the counterclockwise direction. Furthermore, based on the pulse count of paper discharge motor 104 from the detection of the leading edge of the document by paper discharge sensor 132, controller 150 controls to decelerate the drive speed of paper discharge motor 104 just before the trailing edge of the document leaves the nip between the upper and lower roller pair of paper discharge roller 133, so that the document discharged onto paper discharge tray 134 of stack unit H does not jump out.

[0031] 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 132, and then the position of the leading edge of the document being conveyed is detected by counting pulses of the reading motor 103. When the leading edge of the document reaches the position of the second image reading unit 135 of the second reading and conveying unit F, the controller 150 transmits a gate signal indicating the effective image area in the sub-scanning direction of the back side of the document to the second image reading unit 135. This gate signal is transmitted continuously until the trailing edge of the document passes through the second image reading unit 135. Then, while the document is being conveyed by the drive of the reading exit rollers 128 and the CIS exit rollers 129, the second image reading unit 135 reads the image of the back side of the document using a document flow-through reading method (sheet-through reading). Note that the second reading roller 136, which is disposed opposite the second image reading unit 135, prevents the document from floating in the second image reading unit 135 and also serves as a reference white area for acquiring shading data in the second image reading unit 135.

[0032] 2, the separation and feeding unit B is specifically described as including the pickup roller 118, the paper feed belt 120, and the reverse roller 121, but is not limited to this specific example. That is, in the embodiment described below, the feed roller 120A may be used instead of the paper feed belt 120, which has a large nip area and is relatively difficult to correct the skew of the document. In the embodiment described below, the feed roller 120A is used instead of the paper feed belt 120. The feed roller 120A is driven in the paper feed direction by the forward rotation of the paper feed motor 102. The reverse roller 121 is driven to rotate in the direction opposite to the paper feed direction by the forward rotation of the paper feed motor 102. This allows the topmost document picked up by the pickup roller 118 to be separated from the documents below it, and only the topmost document can be fed.

[0033] Example 1 A first embodiment of the present invention will be described with reference to Figures 4 to 7. As shown in Figure 2, the main components of the first embodiment are arranged in a transport path section BC between a separation and feeding section B and a registration section C of the ADF 100. The tilt correction member, which is a main component of the first embodiment and arranged in the transport path section BC of the ADF 100, will be described below. FIG. 4 is a plan view showing the configuration around the tilt correction member of Example 1, and FIG. 5 is an enlarged plan view supplementarily showing the rotation axis of the tilt correction member shown in FIG. 4. FIG. 6 is a side view showing the main configuration and operation of the tilt correction member, and FIG. 7 is an enlarged side view showing the detailed configuration and operation of the tilt correction member of FIGS. 4 to 6. Note that in FIGS. 4 and 5, the upper transport guide plate 19a, the lower transport guide plate 19b, and the surrounding details are omitted for the sake of clarity. In FIGS. 6 and 7, the detailed configuration of the upper transport guide plate 19a and the lower transport guide plate 19b, where the tilt correction member and the rotation axis are provided, are simplified or omitted.

[0034] As shown in Fig. 4, a plurality of skew correction members 10 of the first embodiment are arranged in positions that are symmetrical about the conveyance direction X of the document Do in the conveyance path section BC between the separation and feeding section B and the registration section C of the ADF 100. In the first embodiment, the skew correction members 10 are described as being arranged two above and two below the plane of Fig. 4, centered on the conveyance direction X in accordance with the size of the document Do. The skew correction members 10 other than the one arranged at the top of the plane of Fig. 4 are indicated by dashed lines. The skew correction member 10 is integrally formed from a resin or the like that has good contact durability, since it comes into contact with the leading edge of the document Do being conveyed. The skew correction member 10 is a thin plate-like member with a predetermined thickness, and has an inner surface 10a that is relatively long in the conveying direction X, and an outer peripheral surface 10b that is short and perpendicular to the inner surface 10a.

[0035] The skew correction member 10 extends in the height direction Z, and a columnar or cylindrical rotation shaft 11 (see FIG. 5) is fixed to its lower end. The rotation shaft 11 of the skew correction member 10 is fixed to the skew correction member 10 at an angle with respect to the transport direction X of the document Do. As shown in FIG. 6, a bearing member (not shown) that rotatably supports the rotation shaft 11 together with the skew correction member 10 is provided below the transport guide plate 19b. This allows the skew correction member 10 to rotate or swing together with the rotation shaft 11 within a predetermined angular range.

[0036] In Figure 7, the tilt correction member 10 is shown as seen from the inner surface 10a, but for convenience, the rotation axis 11 is drawn as seen from the side, and as shown in Figures 6 and 7, the length direction of the rotation axis 11 is set to be perpendicular to the inner surface 10a of the tilt correction member 10. The rotation shaft 11 of the tilt correction member 10 is not limited to being provided on the side of the conveying guide plate underside 19b, but may be rotatably supported by a shaft support hole (not shown) provided in a part on the inside of the conveying guide plate.

[0037] 4 and 5, the inner surface 10a of the skew correction member 10 is formed so as to be inclined at a certain angle from the upstream side to the downstream side in the conveying direction X, with the conveying direction X as the center, and is formed in a shape inclined at an angle α in the range of 20° to 40° with respect to the conveying direction X. In other words, the skew correction member 10 is formed in an angular shape that tapers toward the downstream side in the conveying direction X. As indicated by the arrow in FIG. 4, the skew of the document Do is corrected by the inner surface 10a of the skew correction member 10, which is indicated by a solid line and arranged with the conveying direction X as the center.

[0038] As shown only in FIG. 7 , the tilt correction member 10 is provided with a torsion coil spring 12 serving as a biasing means or biasing member. The torsion coil spring 12 is wound around the rotation shaft 11 of the tilt correction member 10, with one end 12a of the torsion coil spring 12 hooked and engaged with the tilt correction member 10 and the other end 12b of the torsion coil spring 12 hooked and engaged with the lower side 12b of the conveying guide plate. In this way, the biasing force 12F of the torsion coil spring 12 provided on the tilt correction member 10 constantly imparts a tendency to rotate clockwise, as indicated by the arrow in FIG. 7 , around the rotation shaft 11 as the center of rotation to the tilt correction member 10. The torsion coil spring 12 functions as a biasing member that constantly imparts a tendency to rotate clockwise, as indicated by the arrow in FIG. 7 , around the rotation shaft 11 as the center of rotation to the tilt correction member 10.

[0039] On the other hand, a stopper member 13 that abuts against the upper part of the outer circumferential surface 10b of the inclination correction member 10 is provided on the conveying guide plate 19a (not shown in FIG. 7) so that the inclination correction member 10 can maintain its upright position as shown by the solid line in FIG. 7 against the biasing force of the torsion coil spring 12. The stopper member 13 is a rotation restricting member that restricts the clockwise rotation of the inclination correction member 10 so that the inclination correction member 10 can maintain its upright position against the biasing force 12F of the torsion coil spring 12.

[0040] As shown in FIG. 7, when the document Do (its leading corner) comes into contact with the outer peripheral surface 10b of the tilt correction member 10 from a direction perpendicular to the transport direction X, the transport force of the document Do acts against the biasing force of the torsion coil spring 12 acting on the tilt correction member 10, causing the tilt correction member 10 to rotate counterclockwise as shown by the dashed line in FIG. 7 and take up a retracted position. 4, a case will be described in which the original document Do is transported at an angle such that the upper corner Doa at the leading edge of the original document Do is transported before the lower corner Dob at the leading edge of the original document Do when viewed in plan from upstream to downstream in the transport direction X of the original document Do. When the leading edge corner of the original document Do contacts the skew correction member 10 in a direction perpendicular to the transport direction X, that is, when the leading edge corner of the original document Do contacts the inner surface 10a of the skew correction member 10, the force acting on the skew correction member 10 around the rotation axis 11 is set to be small enough to be negligible.

[0041] As described above, the tilt correction member 10 is configured to be freely displaceable between an upright position shown by solid lines in Figures 6, 7, etc., where the inner surface 10a contacts the transported document Do to correct the tilt of the document Do, and a retracted position shown by dashed lines in Figures 6, 7, etc., where the transport of the document Do is not hindered.

[0042] The operation of the first embodiment will be described. A stack of originals 110 set on an original table 112 of the ADF 100 in Fig. 2 is conveyed by a pickup roller 118, and separated into a single original Do by the cooperative action of a feed roller 120A and a reverse roller 121, and conveyed in a conveying direction X. The separated original Do may be conveyed at an angle on a conveying path BC between a separation and conveying section B and a registration section C, as shown in Fig. 4.

[0043] As illustrated in FIG. 4 , when viewed from the upstream side to the downstream side in the transport direction X of the original document Do, the following describes a single original document Do in a tilted state such that the upper corner Doa at the leading edge of the original document Do is transported before the lower corner Dob. When the original document Do in the state shown in FIG. 4 comes into contact with the inner surface 10a of the skew correction member 10 (see FIGS. 6 and 7 ), almost no force is applied in the rotational direction of the rotating shaft 11, and the skew correction member 10 does not retract as indicated by the dashed line. In this state, the inner surface 10a of the skew correction member 10, which is substantially stationary, applies a skew correction force to the upper corner Doa at the leading edge of the original document Do, thereby correcting the skew of the single original document Do during this process. After correcting the skew of the original document Do, the skew correction member 10 returns to its original upright position by the biasing force of the torsion coil spring 12, ready to correct the skew of the next original document to be transported.

[0044] 6, when original document Do is being transported downstream in the transport direction X with almost no tilt (including the case where original document Do comes into contact with inner surface 10a of skew correction member 10 and the skew of original document Do is corrected as described with reference to FIG. 4), if original document Do comes into contact with outer peripheral surface 10b of skew correction member 10 in a direction perpendicular to transport direction X, the transport force of original document Do causes skew correction member 10 to rotate around rotation axis 11 against the biasing force of torsion coil spring 12, and original document Do passes through in a retracted position that does not impede the passage of original document Do. After that, skew correction member 10 returns to the upright position by the biasing force of torsion coil spring 12, and is ready to correct the skew of the next original document that is to be transported separately.

[0045] According to the first embodiment, with the above-described simple configuration, it is possible to achieve the effect of correcting the skew of the document while the document is being transported.

[0046] Example 2 Second Embodiment A second embodiment of the present invention will be described with reference to Fig. 8. Fig. 8 is a plan view showing a configuration in which a plurality of rows of skew correction members according to the first embodiment are provided for each row of document sizes. A description will be given of a plurality of skew correction members 10 of Example 1, which are arranged for each size of document Do, as shown in Fig. 8. The plurality of (e.g., eight) skew correction members 10-1 to 10-8 shown in Fig. 8 differ from the skew correction members 10 of Example 1 only in that they are arranged for each document size (including cases where the document position is different), and the specifications and shapes of the skew correction members are the same as those of Example 1 (to clarify this, in Example 2 shown in Fig. 8, skew correction members are referred to as skew correction members 10-1 to 10-8).

[0047] In Figure 8, a pair of tilt correction members 10-1 and 10-2 are arranged at positions symmetrical above and below the center line of the transport direction X of the document Do, and are arranged to correspond to, for example, an A5 document size, a pair of tilt correction members 10-3 and 10-4 to correspond to, for example, an A4 document size, a pair of tilt correction members 10-5 and 10-6 to correspond to, for example, a B4 document size, and a pair of tilt correction members 10-7 and 10-8 to correspond to, for example, an A3 document size.

[0048] With the eight skew correction members 10-1 to 10-8 arranged in this manner, when skew correction of an A5-sized document Do is performed by the inner surfaces 10a of the skew correction members 10-1 and 10-2, the contact and conveying force of the document Do perpendicular to the outer surface 10b causes the correction members 10-1 and 10-2 to retract, allowing the skew-corrected A5-sized document Do to be transported and passed without any problems. Similarly, when skew correction of an A4-sized document Do is performed by the skew correction members 10-3 and 10-4, the contact and conveying force of the document Do perpendicular to the outer surface 10b causes the skew correction members 10-3 and 10-4 to retract, allowing the skew-corrected A4-sized document Do to be transported and passed without any problems. The same applies when skew correction is performed by the other skew correction members 10-5, 10-6, 10-7, and 10-8.

[0049] According to the second embodiment described above, by providing multiple rows of tilt correction members, tilt correction can be performed even when the paper size and document position are different. This has the effect of reducing the document tilt even if the document is not set accurately, thereby improving the ease of use of the image reading device for users.

[0050] Example 3 A third embodiment of the present invention will be described with reference to Figs. 9 to 14. Fig. 9 is a simplified enlarged plan view showing the main configuration (tilt correction member, locking mechanism) of the third embodiment, and Fig. 10 is a simplified side view showing the main configuration and operation of the third embodiment. Fig. 11 is a simplified enlarged plan view showing an operation example 1 of the third embodiment, and Fig. 12 is a simplified side view showing the operation example 1 of the third embodiment. Fig. 13 is a simplified enlarged plan view showing an operation example 2 of the third embodiment, and Figs. 14(a) to 14(c) are simplified side views showing the operation process of the operation example 2 shown in Fig. 13. 9 and 11, the rotation shaft 11 of the tilt correction member 10A of the third embodiment is shown as viewed from the side, similar to the rotation shaft 11 of the tilt correction member 10 of the first embodiment, for the sake of convenience.

[0051] 4 to 7, the third embodiment is different from the first embodiment shown in Fig. 4 to 7 in that the tilt correction member 10 is replaced with a tilt correction member 10A having a locking mechanism 60. As shown in Fig. 9 and Fig. 10, the tilt correction member 10A has a part of the locking mechanism 60 provided at an upper part of the rear end of the tilt correction member 10A in the drawing, at a position protruding further rearward than the rear end of the tilt correction member 10A.

[0052] The lock mechanism 60 has a lock rotation shaft 61 that serves as a rotation fulcrum, and is provided above the correction member 10A in an upright position, as shown in Figures 9 and 10. The lock mechanism 60 is mainly composed of the lock rotation shaft 61, a lock arm 63 that has one end fixed to the lock rotation shaft 61 and the other end extending below the inner surface 10a of the correction member 10A, and a hook-shaped or L-shaped lock claw 62 that is formed on the other end of the lock arm 63.

[0053] 9 and 10, as well as in FIGS. 11 and 12 which show an example in which the document does not come into contact with the locking mechanism 60, and in FIGS. 13 and 14 which show an example in which the document comes into contact with the locking mechanism 60, the locking rotation shaft 61, locking claw 62, locking arm 63, etc. which constitute the locking mechanism 60 are actually positioned on the far side of the inner surface 10a in each of the figures showing the inclination correction member 10A, but are intentionally shown as being positioned on the inner surface 10a side to make the figures easier to see.

[0054] Next, an operation example 1 of the embodiment 3 will be described. As shown in Figures 11 and 12, when the document Do does not come into contact with the locking mechanism 60, the locking mechanism 60 normally stops in the orientation and state shown in Figure 12 due to its own weight, and the locking claw 62 of the locking mechanism 60 is engaged with a locking hole (not shown) formed in the conveying guide plate lower portion 19b, thereby entering a locked state. With the correction member 10A and locking mechanism 60 in this state, as shown in FIG. 11, when an original document Do (for example, the same original document Do as shown in FIG. 4) is transported in an inclined state in the transport direction X, the original document Do first comes into contact with the correction member 10A shown in FIG. 11, and even if the correction member 10A tries to rotate counterclockwise as shown by the dashed line in FIG. 12, as described above, the locking claw 62 is engaged with the locking hole (not shown) formed in the lower transport guide plate 19b and is in a locked state, so the correction member 10A does not retract to the dashed line state shown in FIG. 10 and does not occupy the retracted position.

[0055] Thus, when a single document Do in a tilted state similar to that shown in FIG. 4 comes into contact with the inner surface 10a of the skew correction member 10A (see FIGS. 11 and 12), almost no force is applied in the rotational direction of the rotating shaft 11, and the skew correction member 10A does not retract as shown by the dashed line. In this state, the skew of the document Do is corrected by the document Do coming into contact with the inner surface 10a of the skew correction member 10A, and in this process, the skew of the single document Do is corrected. After correcting the skew of the document Do, the skew correction member 10A returns to its original upright position by the biasing force of the torsion coil spring 12, and is ready to correct the skew of the next document that is to be separated and conveyed.

[0056] An operation example 2 of the third embodiment will now be described. As shown in Figures 13 and 14, when the transported document Do first contacts the lock mechanism 60, the lock claw 62 of the lock arm 63 is engaged with the lock hole (not shown) of the lower transport guide plate 19b in Figure 14(a) to be in a locked state. In this state, when the document Do is transported from the transport direction X as shown in Figure 14(b), the transport force of the document Do is transmitted to the lock arm 63, thereby releasing the locked state between the lower transport guide plate 19b and the lock claw 62, and the lock arm 63 rotates around the lock rotation shaft 61 in the clockwise direction as indicated by the solid arrow.

[0057] Immediately after the locking claw 62 and the lower conveying guide plate 19b are released from their locked state and the locking arm 63 rotates clockwise around the locking rotation shaft 61, the leading edge of the document Do is further conveyed and comes into contact with the outer peripheral surface 10b of the skew correction member 10A, causing the skew correction member 10A to rotate counterclockwise as indicated by the solid arrow around the rotation shaft 11. The skew correction member 10A then retracts to the retracted position, similar to the state shown by the dashed line in FIG.

[0058] In this way, in operation example 2, the document Do is not retracted unless it comes into contact with the outer surface 10b of the inclination correction member 10A from a direction perpendicular to the conveying direction X, thereby increasing the document inclination correction power.

[0059] According to the third embodiment described above, the locking mechanism prevents the document from retracting unless it reliably contacts the locking mechanism from a direction perpendicular to the transport direction, thereby providing the effect of increasing the correction power for document inclination.

[0060] Example 4 A fourth embodiment of the present invention will be described with reference to Figures 15 to 18. The main configuration of the fourth embodiment will be described with respect to skew correction members that function as paper skew prevention devices disposed in the three paper feed units 24 of the copying machine 1 shown in Figure 1. Fig. 15 is a plan view showing the configuration around the tilt correction member of Example 4, and Fig. 16 is an enlarged plan view supplementarily showing the rotation axis of the tilt correction member shown in Fig. 15. Fig. 17 is a side view showing the main configuration and operation of the tilt correction member, and Fig. 18 is an enlarged side view showing the detailed configuration and operation of the tilt correction member of Figs. 15 and 16. In order to simplify the illustration, the upper transport guide plate 79a, the lower transport guide plate 79b, and the surrounding details are omitted in Fig. 15. In Fig. 16 and Fig. 17, the detailed configurations of the upper transport guide plate 79a and the lower transport guide plate 79b for providing the tilt correction member and the rotation axis are simplified or omitted.

[0061] The fourth embodiment differs from the first embodiment mainly in that the skew correction member 10, which was disposed in the transport path section BC of the ADF 100, is disposed in at least one of the transport path sections K of the three paper feed means 24. The fourth embodiment also differs from the first embodiment in that a sheet P is used instead of a document Do as the sheet-like recording medium to be transported, a pickup roller 70 is used instead of the pickup roller 118, a feed roller 71 is used instead of the feed roller 120A, a separation roller 72 is used instead of the reverse roller 121, and a feed roller 73 is used instead of the pull-out roller 123.

[0062] The configuration of Example 4, including the above differences, can be easily understood and implemented by a person skilled in the art if the upper corner portion Doa at the leading edge of the document Do is replaced with the upper corner portion Pa at the leading edge of the paper P, and the lower corner portion Dob at the leading edge of the document Do is replaced with the lower corner portion Pb at the leading edge of the paper P, and therefore further explanation will be omitted to avoid duplication.

[0063] The operation of the fourth embodiment will now be described. A stack of sheets P set in the sheet feeding means 24 of the copying machine 1 of Fig. 1 is transported by the pickup roller 70 of Fig. 15, and separated into a single sheet P by the cooperative action of the feed roller 71 and separation roller 72, which is transported in the transport direction X. The separated sheet P may be transported at an angle in the transport path section K as shown in Fig. 15.

[0064] As shown in FIG. 15, when viewed from the upstream side to the downstream side of the sheet P's transport direction X in a plan view, a single sheet P is tilted so that the upper corner Pa at the leading edge of the sheet P is transported before the lower corner Pb. When the single sheet P in the state shown in FIG. 15 comes into contact with the inner surface 10a of the skew correction member 10 (see FIG. 17), almost no force is applied in the rotation direction of the rotating shaft 11, and the skew correction member 10 does not retract as shown by the dashed line. In this state, the inner surface 10a of the skew correction member 10, which is substantially stationary, applies a skew correction force to the upper corner Pa at the leading edge of the sheet P, thereby correcting the skew of the single sheet P during this process. After correcting the skew of the sheet P, the skew correction member 10 returns to its original upright position by the biasing force of the torsion coil spring 12, ready to correct the skew of the next sheet of paper to be transported.

[0065] 17, when the paper sheet P is transported downstream in the transport direction X with almost no tilt (including the case where the paper sheet P comes into contact with the inner surface 10a of the skew correction member 10 and the skew of the paper sheet P is corrected as described with reference to FIG. 15), if the paper sheet P comes into contact with the outer peripheral surface 10b of the skew correction member 10 in a direction perpendicular to the transport direction X, the transport force of the paper sheet P causes the skew correction member 10 to rotate around the rotation axis 11 against the biasing force of the torsion coil spring 12, and the paper sheet P passes through in a retracted position that does not impede the passage of the paper sheet P. Thereafter, the skew correction member 10 returns to the upright position by the biasing force of the torsion coil spring 12, and is ready to correct the skew of the next paper sheet that is transported separately.

[0066] According to the fourth embodiment, with the above-described simple configuration, it is possible to correct the skew of the paper while the paper is being transported.

[0067] Example 5 A fifth embodiment of the present invention will be described with reference to Fig. 19. Fig. 19 is a plan view showing a fourth embodiment in which a plurality of rows of tilt correction members are provided for each row of paper sizes. In Example 5, instead of the multiple tilt correction members 10 arranged for each document size described in Example 2, multiple tilt correction members 10 are arranged for each paper size. Since this can be easily understood and implemented from the contents of Example 2, further explanation will be omitted.

[0068] According to the fifth embodiment described above, by providing multiple rows of tilt correction members, tilt can be corrected even when the paper size or paper position is different. This has the effect of reducing paper tilt even if the paper is not set accurately, thereby improving the ease of use of the image forming apparatus and paper feeder for users.

[0069] Example 6 A sixth embodiment of the present invention will be described with reference to Figs. 20 to 25. Fig. 20 is a simplified enlarged plan view showing the main configuration (tilt correction member, locking mechanism) of the sixth embodiment, and Fig. 21 is a simplified side view showing the main configuration and operation of the sixth embodiment. Fig. 22 is a simplified enlarged plan view showing an operation example 1 of the sixth embodiment, and Fig. 23 is a simplified side view showing the operation example 1 of the sixth embodiment. Fig. 24 is a simplified enlarged plan view showing an operation example 2 of the sixth embodiment, and Figs. 25(a) to 25(c) are simplified side views showing the operation process of the operation example 2 shown in Fig. 24. The rotation shaft 11 of the tilt correction member 10A of the sixth embodiment shown in FIGS. 20 and 22 is shown as viewed from the side for convenience, similar to the rotation shaft 11 of the tilt correction member 10 of the sixth embodiment.

[0070] 15 to 18, the sixth embodiment is different from the third embodiment shown in Fig. 15 to 18 in that the sixth embodiment includes a tilt correction member 10A having a locking mechanism 60 instead of the tilt correction member 10. As shown in Fig. 20 and Fig. 21, the tilt correction member 10A has a part of the locking mechanism 60 provided at an upper part of the rear end of the tilt correction member 10A in the drawing, at a position that protrudes further rearward than the rear end of the tilt correction member 10A.

[0071] Next, an operation example 1 of the embodiment 6 will be described. As shown in Figures 22 and 23, when the paper P does not come into contact with the locking mechanism 60, the locking mechanism 60 normally stops in the orientation and state shown in Figure 23 due to its own weight, and the locking claw 62 of the locking mechanism 60 is engaged with a locking hole (not shown) formed in the lower conveying guide plate 79b, thereby entering a locked state. With the correction member 10A and locking mechanism 60 in this state, as shown in FIG. 22, when a sheet of paper P (for example, the same sheet of paper P as shown in FIG. 15) is transported in an inclined state in the transport direction X, the sheet of paper P first comes into contact with the correction member 10A shown in FIG. 22, and even if the correction member 10A tries to rotate counterclockwise as shown by the dashed line in FIG. 23, the correction member 10A does not retract to the dashed line state shown in FIG. 10 and does not occupy the retracted position because the locking claw 62 is engaged with the locking hole (not shown) formed in the lower transport guide plate 79b as described above and is in a locked state.

[0072] Thus, when a sheet of paper P in a tilted state similar to that shown in Figure 4 comes into contact with the inner surface 10a of skew correction member 10A (see Figures 22 and 23), almost no force acts in the direction of rotation of rotation shaft 11, and skew correction member 10A does not retract as shown by the dashed line. In this state, the skew of sheet P is corrected as sheet P comes into contact with inner surface 10a of skew correction member 10A, and in this process, the skew of the single sheet of paper P is corrected. After correcting the skew of sheet P, skew correction member 10A returns to its original upright position by the biasing force of torsion coil spring 12, and is ready to correct the skew of the next sheet of paper that is separated and transported.

[0073] An operation example 2 of the sixth embodiment will now be described. As shown in Figures 24 and 25, when the conveyed sheet P first comes into contact with the lock mechanism 60, the lock claw 62 of the lock arm 63 is engaged with the lock hole (not shown) of the lower conveying guide plate 79b in Figure 25(a) and is in a locked state. In this state, when the sheet P is conveyed from the conveying direction X, as shown in Figure 25(b), the conveying force of the sheet P is transmitted to the lock arm 63, thereby releasing the locked state between the lower conveying guide plate 79b and the lock claw 62, and the lock arm 63 rotates around the lock rotation shaft 61 in the clockwise direction as indicated by the solid arrow.

[0074] Immediately after the locking claw 62 and the lower conveying guide plate 79b are released from their locked state and the locking arm 63 rotates clockwise around the locking rotation shaft 61, the leading edge of the paper P is further conveyed and comes into contact with the outer peripheral surface 10b of the skew correction member 10A, causing the skew correction member 10A to rotate counterclockwise as indicated by the solid arrow around the rotation shaft 11. Then, the correction member 10A retracts to the retracted position, similar to the state shown by the dashed line in FIG. In this way, in operation example 2, the paper P is not retracted unless it comes into contact with the outer surface 10b of the skew correction member 10A from a direction perpendicular to the conveying direction X, thereby increasing the paper skew correction power.

[0075] According to the sixth embodiment described above, the locking mechanism prevents the paper from retracting unless it reliably contacts the locking mechanism from a direction perpendicular to the transport direction, thereby improving the ability to correct paper skew.

[0076] It can be said that Examples 1 to 6 essentially describe the following aspects and effects. That is, the first aspect is an image reading device such as ADF 100 that transports a document to an image reading unit such as first image reading unit 131 or second image reading unit 135, and has a plurality of tilt correction members such as tilt correction member 10 provided with a rotation fulcrum inclined with respect to a transport direction such as document transport direction X on a transport path such as transport path section BC that transports the document after separation into one sheet to the next document transport member such as pull-out roller 123, in a direction perpendicular to the transport direction.

[0077] With this configuration, according to the first aspect, it is possible to correct the skew of the document while conveying the document with a simple configuration.

[0078] In a second aspect, in the first aspect, the tilt correction members are arranged in a plurality of rows in a direction perpendicular to the transport direction. According to the second aspect, by using multiple rows of tilt correction members, tilt can be corrected even when the document size or document position varies. Even if the document is not set accurately, the document tilt can be reduced, improving the ease of use of the image reading device for users.

[0079] In the third aspect, in the first or second aspect, the tilt correction member is configured to be rotatable so as to occupy a retracted position where the tilt correction member does not correct the tilt of the document when the document comes into contact with the tilt correction member, such as tilt correction member 10A, which has a surface such as outer peripheral surface 10b that is a surface perpendicular to the conveying direction, and has a locking mechanism, such as locking mechanism 60, that prevents the tilt correction member from rotating to the retracted position. With this configuration, according to the third aspect, the locking mechanism prevents the document from retracting unless the document reliably contacts the locking mechanism from a direction perpendicular to the transport direction, thereby increasing the correction power for document inclination.

[0080] The fourth aspect is a paper skew prevention device that prevents skew of paper such as paper P, and is a paper skew prevention device that has multiple skew correction members such as skew correction member 10, which have a rotation fulcrum inclined with respect to a conveying direction such as paper conveying direction X, on a conveying path such as conveying path K that conveys paper after separation into single sheets to a paper conveying member such as the next feed roller 73, in a direction perpendicular to the conveying direction. With this configuration, according to the fourth aspect, it is possible to correct the skew of the paper while transporting the paper with a simple configuration.

[0081] In a fifth aspect, in the fourth aspect, the tilt correction members are arranged in a plurality of rows in a direction perpendicular to the transport direction. According to the fifth aspect, by providing multiple rows of skew correction members, skew can be corrected even when the paper size or paper position is different. This reduces paper skew even if the paper is not set correctly, improving the ease of use of an image forming apparatus equipped with a skew paper prevention device.

[0082] A sixth aspect is a paper skew prevention device according to the fourth or fifth aspect, characterized in that the skew correction member is configured to be rotatable so as to occupy a retracted position where the skew correction member does not correct the skew of the paper when the paper comes into contact with the skew correction member, such as skew correction member 10A, which has a surface such as outer surface 10b that is perpendicular to the conveying direction, and has a locking mechanism that prevents the skew correction member from rotating to the retracted position. With this configuration, according to the sixth aspect, the locking mechanism prevents the sheet from retracting unless the sheet reliably contacts the locking mechanism from a direction perpendicular to the transport direction, thereby increasing the ability to correct sheet skew.

[0083] A seventh aspect is an image forming apparatus characterized by comprising the image reading device according to any one of the first to third aspects and / or the paper skew prevention device according to any one of the fourth to sixth aspects. With this configuration, according to the seventh aspect, the above-mentioned effects are achieved in an image forming apparatus equipped with the image reading device described in any one of the first to third aspects and / or the paper skew prevention device described in any one of the fourth to sixth aspects.

[0084] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and unless otherwise specifically limited in the above description, various modifications and variations are possible within the spirit and scope of the present invention as defined in the claims. For example, the technical matters described in the above embodiments, examples, or variations may be appropriately combined.

[0085] The effects appropriately described in the embodiments of the present invention are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention. [Explanation of symbols]

[0086] 1. Copier (an example of an image forming device) 2 Paper feed section 3 Image forming unit 4 Scanner section 5. Contact Glass 10, 10A Tilt correction member 10a Inner surface 10b Outer surface 11 Rotation axis 12 Torsion coil spring 13 Stopper member 19 Transport guide plate 19a On the transport guide plate 19b Under the transport guide plate 24 Paper feeding means (an example of a paper skew prevention device) 31 Exposure equipment 32 Photosensitive drum 33 Developing device 34 Transfer belt 35 Fixing device 60 Locking mechanism 61 Locking pivot 62 Locking Claw 63 Lock Arm 64 Locking Claw 70 Pickup roller 71 Feeding roller 72 Separation roller 73 Feed roller (an example of a paper transport member) 79a On the transport guide plate 79b Under the transport guide plate 100 ADF (an example of an image reader) B Separation feeding section BC transport path section C Resist section Do manuscript K Conveyor path section P paper X Original and paper transport direction Y Front / back / depth direction Z height direction [Prior art documents] [Patent documents]

[0087] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-016600 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-084185 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-270560

Claims

1. An image reading device that conveys a document to an image reading unit, An image reading device that has multiple tilt correction members, each with a rotation fulcrum tilted relative to the transport direction, on a transport path that transports the document after separation into individual sheets to the next document transport member, in a direction perpendicular to the transport direction.

2. 2. The image reading device according to claim 1, The image reading device has a plurality of rows of the tilt correction members arranged in a direction perpendicular to the transport direction.

3. 2. The image reading device according to claim 1, the skew correction member is configured to be rotatable so as to occupy a retracted position where the skew correction member does not correct the skew of the document when the document comes into contact with the skew correction member having a surface perpendicular to the transport direction, an image reading device having a locking mechanism for preventing the tilt correction member from rotating to the retracted position;

4. A paper skew prevention device that prevents paper from skewing, A paper skew prevention device that has multiple tilt correction members, each with a rotation fulcrum tilted relative to the transport direction, on a transport path that transports the paper after separation to the next paper transport member, in a direction perpendicular to the transport direction.

5. 5. The sheet skew prevention device according to claim 4, The paper skew prevention device has a plurality of rows of the skew correction members arranged in a direction perpendicular to the conveying direction.

6. 5. The sheet skew prevention device according to claim 4, the skew correction member is configured to be rotatable so as to occupy a retracted position where the skew correction member does not correct the skew of the paper when the paper comes into contact with the skew correction member having a surface perpendicular to the transport direction, The paper skew prevention device further comprises a locking mechanism for preventing the skew correction member from rotating to the retracted position.

7. 5. An image forming apparatus comprising: an image reading device according to claim 1; and / or a sheet skew prevention device according to claim 4.

Images