Feeding device, image reading device, and image forming device

Abstract

To provide a feeding device, an image reading device, and an image forming device capable of preventing entry of a tip part of a sheet into a gap between a sheet contact surface and a loading plate and preventing occurrence of a feeding failure.SOLUTION: A relay member 40 serving as a contact member that contacts a manuscript abutment surface 151 serving as a sheet contact surface with which a tip of a manuscript loaded on a movable manuscript table 111 comes into contact, is provided at a downstream end part of the movable manuscript table 111 which serves as a sheet loading part on which a manuscript MS serving as a sheet is loaded and whose downstream end part in a manuscript conveyance direction is elevated / lowered, the relay member .SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, a feeding device is known that has a sheet stacking section for stacking sheets and having at least a downstream end in a sheet transport direction that moves up and down, and a sheet contact surface that contacts the leading edge of a sheet stacked on the sheet stacking section.

[0003] Patent document 1 describes a feeding device in which a protrusion is provided at the downstream end of the loading plate in the sheet transport direction in order to prevent the leading edge of the sheet from slipping into the gap between the sheet contact surface and the loading plate which serves as the sheet stacking section, and a groove is provided at the point opposite the protrusion on the sheet contact surface to allow the protrusion to escape. Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the leading edge of the sheet is wavy, the leading edge of the sheet may get caught in the groove during feeding, resulting in poor feeding. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a feeding device having a sheet stacking section for stacking sheets and in which at least the downstream end in the sheet transport direction rises and falls, and a sheet contact surface with which the leading ends of the sheets stacked on the sheet stacking section come into contact, wherein a contact member is provided on the sheet stacking section for contacting the sheet contact surface. Effect of the Invention

[0006] According to the present invention, it is possible to prevent the leading edge of the sheet from slipping into the gap between the sheet contact surface and the stacking plate, and also to prevent the occurrence of poor feeding. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a copying machine according to an embodiment. [Diagram 2] FIG. 1 is a schematic diagram of an automatic document feeder (ADF). [Diagram 3] Block diagram of the ADF control system. [Figure 4] FIG. [Diagram 5] FIG. 11 is a schematic cross-sectional view of the vicinity of a groove in a conventional document setting unit. [Figure 6] FIG. 2 is a schematic configuration diagram of a document setting unit according to the embodiment. [Figure 7] FIG. 2 is a perspective view of a main part of a document setting unit according to the embodiment. [Figure 8] FIG. [Figure 9] 4 is an enlarged perspective view of a main portion showing the vicinity of the center in the width direction on the downstream side in the transport direction of the movable document table. FIG. [Figure 10] FIG. 13 is an enlarged configuration diagram of a main part of an original setting unit A provided with a relay member according to a first modified example. [Figure 11] FIG. 13 is a perspective view showing a relay member according to a second modified example. [Figure 12] 13 is a cross-sectional view of a relay member of a second modified example taken along a plane parallel to the document transport direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The best mode for carrying out the present invention will be described below with reference to the drawings. Note that a person skilled in the art can easily modify and alter the present invention within the scope of the claims to create other embodiments, and these modifications and alterations are included in the scope of the claims. The following description is an example of the best mode for carrying out the present invention, and does not limit the scope of the claims.

[0009] FIG. 1 is a schematic diagram of a copying machine as an image forming apparatus according to an embodiment. As shown in FIG. 1, a copying machine 1 includes an automatic document feeder (ADF) 100, a paper feed section 2 serving as a feeding device, and an image forming section 3.

[0010] The paper feeding section 2 has feeding cassettes 21 and 22 that store transfer papers (paper) of different sizes as recording materials, and a feeding means 23 consisting of various rollers that transport the transfer papers stored in the feeding cassettes 21 and 22 to the image forming section 3.

[0011] The image forming unit 3 includes an exposure device 31, photoconductor drums 32 for each of four colors, a developing device 33, a transfer belt 34, and a fixing device 35. The image forming unit 3 exposes each photoconductor drum 32 with the exposure device 31 based on image data of a document read by the image reading unit of the ADF 100 to form a latent image of each color on each photoconductor drum 32. Then, the developing device 33 for each color supplies a toner of each color to each photoconductor drum 32, and develops the latent image of each photoconductor drum 32 to form a toner image. Then, the image forming unit 3 transfers the toner image of each photoconductor drum 32 to the recording paper supplied from the paper feed unit 2 with the transfer belt 34, and then the fixing device 35 melts the toner of the toner image transferred to the recording paper to fix the color image on the recording paper.

[0012] FIG. 2 is a schematic diagram of an automatic document feeder (ADF) 100 having a function as an image reading device, and FIG. 3 is a block diagram of a control system of the ADF 100. As shown in FIG. As shown in FIG. 2, the ADF 100 includes an original setting section A where a stack of originals is set, a separation and feeding section B which separates and feeds each original from the set stack of originals, and a registration section C which performs primary abutment alignment on the fed originals and pulls out and transports the aligned originals.

[0013] The ADF 100 also has a turning unit D that turns the transported document and transports the document surface toward the reading side (downward in the figure) by the first image reading unit 131. The ADF 100 also has a first reading and transporting unit E that reads the front surface image of the document from below the contact glass by the first image reading unit 131.

[0014] The ADF 100 also includes a second reading and conveying section F that reads the back image of the document after the front image has been read using the second image reading section 135, a paper discharge section G that discharges the document outside the machine after the front and back images have been read, and a stack section H that holds and stacks the discharged documents.

[0015] 3, the ADF 100 includes motors 101-105 that drive the above-mentioned components, and a controller 150 that controls a series of operations. The controller 150 is connected to a main body control unit 10 that performs overall control of the copier 1 via an I / F 107. An operation unit 11 that allows a user to perform various operations is also connected to the main body control unit 10 via an I / F 106.

[0016] A document stack 110, which is a bundle of sheets to be read, is set in the document setting section A. The document stack 110 is set on a document table 112 including a movable document table 111 as a sheet stacking section. The document stack 110 is set on the document table 112 with the document surface facing upward. At this time, the width direction of the document stack 110 is positioned by a side fence 17 (see FIG. 7) in the sheet width direction, which is a direction perpendicular to the conveying direction.

[0017] The setting of the document stack 110 is detected by a set feeler 113 and a set sensor 114, and information indicating that the document stack 110 has been set is transmitted from the controller 150 to the main body control unit 10 via the I / F 107.

[0018] Furthermore, document length detection sensors 115, 116 provided on the document table surface determine the approximate length of the document stack 110 in the transport direction. Note that, as document length detection sensors 115, 116, for example, a reflective sensor or an actuator type sensor capable of detecting even a single document is used. Also, the document length detection sensors 115, 116 must be positioned so that they can at least determine whether the document is vertical or horizontal for the same document size.

[0019] 2 by a bottom plate lifting motor 105. When no original stack 110 is set on the original table 112, the movable original table 111 is in a lowered state, and this state is detected by a bottom plate HP sensor 117.

[0020] When the set filler 113 and the set sensor 114 detect that the document stack 110 has been set on the document table 112, the controller 150 lifts the movable document table 111. Specifically, the bottom plate lifting motor 105 is rotated forward to lift the movable document table 111 so that the top surface of the document stack 110 comes into contact with the pickup roller 118 of the separation and feeding section B.

[0021] 2 by the action of a cam mechanism driven by pickup motor 101. Also, when movable original table 111 rises and is pushed by the upper surface of original stack 110 on movable original table 111, pickup roller 118 rises in direction c in FIG. 2, and the upper limit can be detected by proper paper feed position sensor 119.

[0022] When a user presses the print key on operation unit 11 and a document feed signal is sent from main body control unit 10 to controller 150 via I / F 107, pickup roller 118 is rotated by forward rotation of feed motor 102. Pickup roller 118 rotates to pick up several documents (ideally one document) on document table 112. The rotation direction is the direction in which the topmost document is transported to the document feed port.

[0023] The paper feed belt 120 is driven in the paper feed direction by the forward rotation of the paper feed motor 102. In addition, 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 to be separated from the documents below it, and only the topmost document to be fed.

[0024] More specifically, the reverse roller 121 contacts the paper feed belt 120 with a predetermined pressure, and when 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.

[0025] 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 falls below the torque of the torque limiter. As a result, the reverse roller 121 rotates in the clockwise direction, which is the normal driving direction, and acts to push back the excess documents. This prevents double feeding of documents.

[0026] The document separated into one sheet by the action of the feed belt 120 and the reverse roller 121 is sent to the registration section C side by the feed belt 120, and after the leading edge is detected by the abutment sensor 122, it proceeds further and abuts against the stopped pull-out roller 123.

[0027] Thereafter, the document is fed a predetermined distance from the detection of 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 move pickup roller 118 away from the top surface of the document, and the document is fed only by the conveying force of paper feed belt 120. As a result, the leading edge of the document enters the nip between the upper and lower roller pairs of pull-out roller 123, and the leading edge is aligned (skew correction).

[0028] Pull-out roller 123 has a skew correction function and is a roller for transporting the separated and skew-corrected original to intermediate roller 124, and is driven by the reverse rotation of paper feed motor 102. When paper feed motor 102 is reversed, pull-out roller 123 and intermediate roller 124 are driven, but pickup roller 118 and paper feed belt 120 are not driven.

[0029] 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 pulse by reading the leading and trailing ends of the document with the abutment sensor 122.

[0030] When the document is transported from the registration section C to the turning section D by driving the pull-out roller 123 and the intermediate roller 124, the transport speed in the registration section C is set to be faster than the transport speed in the first reading transport section E. This makes it possible to shorten the processing time for sending the document to the image reading section.

[0031] When the leading edge of the document is detected by the reading entrance sensor 126, the document conveying speed starts to be decelerated to be the same as the reading conveying speed before the leading edge of the document enters the nip between the upper and lower rollers of the reading entrance roller 127. At the same time, the reading motor 103 is driven in the forward direction to drive the reading entrance roller 127, the reading exit roller 128, and the CIS exit roller 129.

[0032] When the controller 150 detects the leading edge of the document by the registration sensor 130, it slows down the document conveying speed over a predetermined conveying distance and temporarily stops the document in front of the first image reading unit 131. In addition, it transmits a temporary stop signal to the main body control unit 10 via the I / F 107.

[0033] When a reading start signal is sent from the main body control unit 10 to the controller 150 via the I / F 107, the controller 150 accelerates the transport of the document, which has been temporarily stopped, so that the transport speed reaches a predetermined transport speed before the leading edge of the document reaches the position of the first image reading unit 131.

[0034] At this time, the position of the leading edge of the document is detected by counting the pulses of the reading motor 103. Next, at the timing when the leading edge of the document reaches the first image reading unit 131, a gate signal indicating an effective image area in the sub-scanning direction (the same direction as the document transport direction) on the front side of the document is transmitted to the main body control unit 10. This gate signal is continuously transmitted until the rear end of the document leaves the first image reading unit 131. Then, while the document is transported by the drive of the reading entrance rollers 127 and the reading exit rollers 128, the first image reading unit 131 reads the front side image of the document.

[0035] In the case of single-sided document reading, the document after the first image reading unit 131 of the first reading and conveying unit E has finished reading the front side image passes through the second reading and conveying unit F and is conveyed to the paper discharge unit G. At this time, when the controller 150 detects the leading edge of the document by the paper discharge sensor 132, it drives the paper discharge motor 104 in the forward direction to rotate the paper discharge roller 133 in the counterclockwise direction. In addition, the controller 150 detects the point immediately before the trailing edge of the document leaves the nip of the upper and lower roller pair of the paper discharge roller 133 based on the pulse count of the paper discharge motor 104 from the detection of the leading edge of the document by the paper discharge sensor 132. Then, immediately before the trailing edge of the document leaves the nip of the upper and lower roller pair of the paper discharge roller 133, the controller 150 controls the paper discharge motor drive speed to be decelerated so that the document discharged onto the paper discharge tray 134 of the stack unit H does not fly out.

[0036] On the other hand, in the case of double-sided document reading, the leading edge of the document is detected by the 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. Then, at the timing 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 on the back side of the document to the second image reading unit 135. This gate signal is continuously transmitted until the trailing edge of the document leaves the second image reading unit 135.

[0037] While the document is transported by the drive of the reading exit rollers 128 and the CIS exit rollers 129, the image on the back side of the document is read by the second image reading unit 135 in a document flow reading mode (sheet-through reading). Note that the second reading roller 136 disposed opposite the second image reading unit 135 suppresses floating of the document 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.

[0038] FIG. 4 is a perspective view of a main portion of a conventional document setting portion A, and FIG. 5 is a schematic cross-sectional view of the vicinity of a groove portion 151a in the conventional document setting portion A. As shown in FIG. Since the movable original table 111 is provided so as to be rotatable about its downstream end in the original transport direction as a fulcrum, a gap is generated between the movable original table 111 and an original abutment surface 151, which serves as a sheet contact surface against which the leading edge of an original is abutted when the original is set. Therefore, if the original set in the original setting section A is a weak original such as thin paper, there is a risk that the leading edge of the bottom original of the original stack will enter the gap between the movable original table 111 and the original abutment surface 151. As a result, there is a risk of poor feeding occurring when feeding the bottom original (last original) of the original stack.

[0039] In the conventional example shown in Fig. 4, the following configuration is used to prevent the leading edge of the document from entering the gap between the movable document table 111 and the document abutment surface 151. That is, a protrusion 111a is provided in the center of the width direction of the leading edge of the movable document table 111, and a groove 151a for allowing the protrusion 111a to escape is provided in the center of the width direction of the document abutment surface 151. With this configuration, the protrusion 111a at the leading edge of the movable document table 111 prevents the leading edge of the document from entering the gap between the movable document table 111 and the document abutment surface 151, thereby suppressing the occurrence of feeding failures.

[0040] 5, in the conventional configuration, the top of groove 151a is located downstream in the document transport direction from the top of document abutment surface 151, and a step is generated in the document transport direction between the top of groove 151a and the top of document abutment surface 151. Therefore, if the leading edge of the document is wavy, the leading edge of the document may get caught on the step, resulting in poor feeding.

[0041] Fig. 6 is a schematic diagram of the document setting unit A in this embodiment, and Fig. 7 is a perspective view of the main parts of the document setting unit A. Fig. 6(a) and Fig. 7(a) show a state in which the movable document table 111 is located at the lowest position, and Fig. 6(b) and Fig. 7(b) show a state in which the movable document table 111 is located at the highest position.

[0042] 7, a pair of side fences 17 are provided on the movable original table 111 so as to be movable in the width direction. The original MS set on the movable original table 111 is restricted in the width direction by the pair of side fences 17 so that the center of the original MS in the width direction is positioned at the center of the movable original table 111 in the width direction.

[0043] 6, the document setting unit A is provided with a rotatable lift plate 140 for lifting and lowering the downstream end of the movable document table 111 in the transport direction. By rotating the bottom plate lift motor 105 in the normal direction, the lift plate 140 rotates clockwise from the state shown in FIG. 6(a), and the movable document table 111 rotates clockwise in the figure. This causes the downstream end of the movable document table 111 in the transport direction to rise.

[0044] In this embodiment, document pre-separation section 152 is provided as an inclined surface that is inclined upward from the top of document abutment surface 151 toward the downstream side in the document transport direction. Even if the leading edge of the top document of the document stack abuts against the inclined surface of document pre-separation section 152, the document can easily climb up the inclined surface by the transport force of pickup roller 80. On the other hand, the second and subsequent documents can be separated from each other because the force required to climb up the inclined surface when the leading edge of the document abuts against the inclined surface of document pre-separation section 152 exceeds the frictional force between the documents.

[0045] In this embodiment, a friction plate 153 is provided in the center in the width direction of the document pre-separator 152. This increases the force required to climb the inclined surface of the document pre-separator 152, thereby improving the separation ability of the document pre-separator 152.

[0046] In this embodiment, a relay member 40 is provided as a contact member that contacts the document abutment surface 151 at the center in the width direction of the downstream end of the movable document table 111 in the transport direction. The relay member 40 is attached to the movable document table 111 so as to be freely rotatable.

[0047] FIG. 8 is a schematic perspective view of the relay member 40, and FIG. 9 is an enlarged perspective view of a main portion showing the vicinity of the center in the width direction on the downstream side of the movable original table 111 in the transport direction. As shown in FIG. 8, a pair of rotating shafts 40a and 40b are provided at the upstream end of the relay member 40 in the transport direction.

[0048] 9, a mounting groove 111b is provided in the center of the width direction of the downstream end of the movable original table 111 in the transport direction. On both ends of the mounting groove 111b in the width direction, shaft mounting portions 11a and 11b to which the rotating shaft portions 40a and 40b of the relay member 40 are rotatably mounted are provided. The shaft mounting portions 11a and 11b are ring-shaped with a notch on the downstream side in the transport direction, and the inner diameter is slightly larger than the outer diameter of the rotating shaft portions 40a and 40b.

[0049] The relay member 40 is attached to the movable document table 111 so as to be freely rotatable by fitting the rotary shaft portions 40a and 40b of the relay member 40 into the shaft attachment portions 11a and 11b through the cutouts of the shaft attachment portions 11a and 11b.

[0050] 6(a), when the movable document table 111 is in the lowest position, the relay member 40 is in contact with the document abutment surface 151 in an inclined position such that the downstream end in the transport direction is positioned upward. This position allows the relay member 40 to come into contact with the document abutment surface 151 by its own weight.

[0051] The movable original table 111 rotates around its upstream end in the transport direction as a fulcrum, and the downstream end of the movable original table 111 in the transport direction moves up and down along an arc-shaped path. Therefore, the gap between the original abutment surface 151 and the downstream end of the movable original table 111 in the transport direction changes due to the lifting and lowering.

[0052] In this embodiment, the relay member 40 is rotatably attached to the movable original table 111. As a result, even if the gap between the original abutment surface 151 and the downstream end of the movable original table 111 in the transport direction changes due to the elevation of the movable original table 111, the relay member 40 can rotate to maintain contact with the original abutment surface 151. In addition, by rotatably attaching the relay member 40 to the movable original table 111, it is possible to suppress an increase in the contact pressure with the original abutment surface 151 due to the elevation of the relay member 40. This makes it possible to suppress an increase in the sliding resistance of the relay member 40 against the original abutment surface 151 when the movable original table 111 is elevated. As a result, the movable original table 111 can be elevated without any problems.

[0053] In this embodiment, the relay member 40 closes the gap between the downstream end of the movable original table 111 in the transport direction and the original abutment surface 151. This makes it possible to prevent the leading edge of the original from slipping into the gap between the movable original table 111 and the original abutment surface 151, thereby suppressing the occurrence of feeding failures.

[0054] Furthermore, in this embodiment, by rotatably mounting the relay member 40 on the movable original table 111, it is possible to prevent the contact pressure between the relay member 40 and the original abutment surface 151 from becoming high. As a result, when the movable original table 111 is raised and lowered, the relay member 40 slides smoothly without getting caught on the original abutment surface 151. Therefore, as shown in Figs. 4 and 5, even if the groove 151a is not provided on the original abutment surface 151, the movable original table 111 can be raised and lowered smoothly, and the groove 151a can be eliminated. As a result, a situation in which a document with a wavy leading edge gets caught in the groove and feeding failure occurs is prevented, and the document can be fed well.

[0055] In this embodiment, the transport reference is the center of the width direction, and by providing a relay member 40 in the center of the width direction, it is possible to prevent the leading edge of the document from slipping into the gap between the movable document table 111 and the document abutment surface 151 for all document sizes that can be transported by this ADF.

[0056] A plurality of relay members 40 may be provided at predetermined intervals in the width direction. By providing a plurality of relay members 40 at predetermined intervals in the width direction, it is possible to prevent the end of the document in the width direction from slipping into the gap between the movable document table 111 and the document abutment surface 151. In addition, the relay member 40 may be made longer in the width direction to prevent the end of the document in the width direction from slipping in.

[0057] Incidentally, providing one relay member 40 at the center in the width direction has the advantage of making the device inexpensive. Also, the sliding resistance against the document abutment surface 151 when the movable document table 111 is raised and lowered can be reduced compared to providing multiple relay members 40 at a predetermined interval in the width direction or lengthening the relay member 40 in the width direction.

[0058] When the downstream end in the transport direction of the movable document table 111 rises and the tip end (downstream end in the transport direction) of the relay member 40 is positioned above the top of the document abutment surface 151, the relay member 40 rotates counterclockwise in Fig. 6 due to its own weight. Then, as shown in Fig. 6(b) and Fig. 7(b), the relay member 40 comes into contact with the document pre-separation section 152.

[0059] The contact of the relay member 40 with the document pre-separation section 152 can prevent the leading edge of the document from getting caught between the document pre-separation section 152 and the relay member 40. In addition, the contact of the relay member 40 with the document pre-separation section 152 can cause the relay member 40 to assume an inclined position with the leading edge of the relay member 40 positioned upward, as shown in Fig. 6(b). This allows the leading edge of the document to be smoothly delivered from the relay member to the document pre-separation section 152, and can prevent the leading edge of the document from getting caught in the pre-separation section, resulting in poor feeding.

[0060] In this embodiment, the weight of the relay member 40 maintains contact between the relay member 40 and the document abutment surface 151, but the biasing force of a biasing member such as a torsion spring may maintain contact between the relay member 40 and the document abutment surface 151. Alternatively, for example, the rotating shafts 40a and 40b may be elastic members, and the relay member 40 may be attached to the movable document table 111 via the elastic members. Then, the elastic member may be twisted to bring the relay member 40 into contact with the document abutment surface 151, and the restoring force of the elastic member may maintain contact between the relay member 40 and the document abutment surface 151.

[0061] In this way, by maintaining contact between the relay member 40 and the document abutment surface 151 with the biasing force of the biasing member or the restoring force of the elastic member, the contact can be maintained more reliably than when the contact between the relay member 40 and the document abutment surface 151 is maintained by the weight of the relay member 40. On the other hand, by maintaining contact between the relay member 40 and the document abutment surface 151 by the weight of the relay member 40, the contact pressure of the relay member 40 against the document abutment surface 151 can be suppressed, and the movable document table 111 can be raised and lowered smoothly.

[0062] [Variation 1] Fig. 10 is an enlarged configuration diagram of a main part of the document setting section A provided with the relay member 40 of the first modified example. Fig. 10(a) shows a state in which the movable document table 111 is located at the lowest position, and Fig. 10(b) shows a state in which the movable document table 111 is located at the highest position. In the first modified example shown in FIG. 10, the relay member 40 is an elastic member, and as shown in FIG. 10(a), the relay member 40 is in contact with the document abutment surface 151 by elastic deformation.

[0063] When the downstream end of the movable original table 111 in the transport direction rises and the tip (downstream end in the transport direction) of the relay member 40 is positioned above the top of the original abutment surface 151, the tip of the relay member 40 rotates counterclockwise in Fig. 10 due to a restoring force. Then, as shown in Fig. 10, the relay member 40 abuts against a friction plate 153 provided in the original pre-separation section 152.

[0064] In the first modification, the relay member 40 is an elastic member. As a result, even if the gap between the document abutment surface 151 and the downstream end of the movable document table 111 in the transport direction changes as the movable document table 111 rises and falls, the relay member 40 rotates by its restoring force and can maintain contact with the document abutment surface 151. In addition, the relay member 40 can be prevented from increasing in contact pressure with the document abutment surface 151 due to elastic deformation of the relay member 40. This can prevent an increase in the sliding resistance of the relay member 40 against the document abutment surface 151 when the movable document table 111 rises and falls. This allows the movable document table 111 to rise and fall without any problems.

[0065] 10, a hook portion 111c for hooking the relay member 40 is formed near the downstream end in the document transport direction on the underside of the movable document table 111. The relay member 40 is attached to the movable document table 111 by hooking the hook portion 111c into an engagement hole provided in the relay member 40. Note that the method of attaching the relay member 40 made of an elastic member to the movable document table 111 is not limited to the above, and it can be attached by a known method such as double-sided tape or adhesive.

[0066] Depending on the material of the elastic member constituting the relay member 40, there is a possibility that the relay member 40 may not be firmly fixed to the movable original table 111 using double-sided tape, adhesive, etc. On the other hand, as shown in Fig. 10, by hooking the relay member 40 onto the hook portion 111c of the movable original table 111, the relay member 40 can be satisfactorily fixed to the movable original table 111 regardless of the material of the elastic member constituting the relay member 40.

[0067] The elastic member constituting the relay member 40 is preferably a rubber material such as silicone rubber, which has a higher coefficient of friction with the document than the coefficient of friction with the document on the document placement surface of the movable document table. By using a material such as rubber, which has a high coefficient of friction with the document, as the elastic member constituting the relay member 40, the document at the bottom of the document stack can be prevented from being transported together with the document at the top that is transported by the pickup roller 80, and the occurrence of double feeding can be effectively prevented.

[0068] [Variation 2] FIG. 11 is a perspective view showing a relay board 40 of the second modified example, and FIG. 12 is a cross-sectional view of the relay board 40 of the second modified example taken along a plane parallel to the document transport direction. The relay member 40 of the second modification is provided with a friction member 41 whose contact surface with the document has a higher friction coefficient with the document than the friction coefficient of the document placement surface of the movable document table 111 with the document.

[0069] In the second modification, a rubber material such as silicone rubber is used as the friction member 41, and the friction member 41 is attached to the relay member 40 by hooking it onto a hook portion 42 provided on the relay member 40 as shown in FIG. 12, as in the first modification. Specifically, the relay member 40 is provided with a base portion 40d on which the friction member 41 is placed, which is provided one step lower. A rectangular insertion hole 40c into which the upstream side of the friction member 41 in the conveying direction is inserted is provided on a step surface perpendicular to the conveying direction and extending vertically from the upstream end of the base portion 40d in the conveying direction. The upstream side of the friction member 41 in the conveying direction is inserted into the insertion hole 40c, and an engagement hole provided at the upstream end of the friction member 41 in the conveying direction is hooked onto the hook portion 42, whereby the friction member 41 is attached to the relay member 40. The friction member 41 may be fixed to the base portion 40d of the relay member 40 by using a double-sided tape, an adhesive, or the like.

[0070] In the second modification as well, the bottom document in the document stack that comes into contact with the friction member 41 can be prevented from being transported by the pickup roller 80 together with the top document, and the occurrence of double feeding can be effectively prevented.

[0071] In addition, in this modified example 2, the main body of the relay member 40 contacts the document abutment surface 151, but the friction member 41 does not contact it. This reduces the sliding resistance against the document abutment surface 151 compared to a configuration in which the friction member 41 contacts the document abutment surface 151, and allows the movable document table 111 to move up and down smoothly.

[0072] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the spirit of the present invention described in the claims, unless otherwise specifically limited in the above description.

[0073] For example, in the above embodiment, the present invention is applied to the document set unit A of the ADF as a feeding device, but the present invention can also be applied to the paper feed unit 2 or manual paper feed unit as a feeding device. Also, the paper feed unit 2 or manual paper feed unit to which the present invention is applied can be used not only in electrophotographic image forming apparatuses, but also in inkjet image forming apparatuses.

[0074] The above description is merely an example, and each of the following aspects provides unique effects. (Aspect 1) In a feeding device having a sheet stacking section such as a movable document table 111 on which sheets such as documents MS are stacked and at least the downstream end in the sheet transport direction is raised and lowered, and a sheet contact surface such as a document abutment surface 151 with which the leading ends of the sheets stacked on the sheet stacking section come into contact, a contact member such as a relay member 40 that comes into contact with the sheet contact surface on the sheet stacking section is provided. According to this, the contact member that contacts the sheet contact surface blocks the gap between the downstream end of the sheet stacking section in the sheet transport direction and the sheet contact surface, thereby preventing the leading edge of the sheet from slipping into the gap between the sheet contact surface and the stacking plate. In addition, by rotatably attaching the contact member to the sheet stacking section or by using an elastic member, it is possible to suppress an increase in the contact pressure with the sheet contact surface, and the contact member can slide smoothly against the sheet contact surface when the sheet stacking section is raised or lowered. This makes it possible to eliminate the need for a groove on the sheet contact surface to allow the contact member to escape, and prevents the leading edge of the sheet from getting caught in the groove, thereby suppressing the occurrence of feeding failures.

[0075] (Aspect 2) In the first embodiment, a pair of side fences 17 are provided to position the widthwise center of a sheet such as a document at the widthwise center of a sheet stacking section such as a movable document table 111, and a contact member such as a relay member 40 is provided at the widthwise center of the sheet stacking section. As a result, as described in the embodiment, for all sheet sizes that the feeding device can feed, it is possible to prevent the leading edge of the sheet from slipping into the gap between a sheet stacking section such as the movable document table 111 and a sheet contact surface such as the document abutment surface 151.

[0076] (Aspect 3) In the first or second embodiment, an inclined surface such as the document pre-separation section 152 is provided that is inclined so as to be positioned upward as it moves from the upper end of the sheet contact surface such as the document abutment surface 151 toward the downstream side in the sheet transport direction, and when the downstream end in the sheet transport direction of the sheet stacking section such as the movable document table 111 rises by more than a predetermined amount, a contact member such as the relay member 40 comes into contact with the inclined surface. As described in the embodiment, this prevents the leading edge of a sheet such as a document from getting caught between the inclined surface of the document pre-separation section 152 or the like and the contact member such as the relay member 40. In addition, by contacting the contact member with the inclined surface, the leading edge of the contact member such as the relay member 40 can be inclined so as to be positioned upward. This allows the leading edge of the document to be smoothly delivered from the inside to the document pre-separation section 152, and prevents the leading edge of the document from getting caught on the inclined surface of the pre-separation section or the like, resulting in poor feeding.

[0077] (Aspect 4) In any of the first to third aspects, a contact member such as the relay member 40 is rotatably attached to a sheet stacking portion such as the movable document table 111. According to this, as described in the embodiment, the contact pressure between the contact member and the sheet contact surface such as the document abutment surface 151 can be suppressed by rotating the contact member such as the relay member 40. This allows the contact member to smoothly slide against the sheet contact surface when a sheet stacking unit such as the movable document table 111 is raised and lowered, while maintaining contact of the contact member with the sheet contact surface. This makes it possible to eliminate the need for a groove portion for allowing the contact member to escape from the sheet contact surface, and prevents the leading edge of the sheet from getting caught in the groove portion, thereby suppressing the occurrence of feeding failures.

[0078] (Aspect 5) In any of the first to third aspects, the contact members such as the relay member 40 are made of an elastic member. According to this, as described in the embodiment, the contact pressure between the contact member and the sheet contact surface such as the document abutment surface 151 can be suppressed by elastically deforming the contact member such as the relay member 40. This allows the contact member to smoothly slide against the sheet contact surface when a sheet stacking unit such as the movable document table 111 is raised and lowered while maintaining contact of the contact member with the sheet contact surface. This makes it possible to eliminate the need for a groove portion for allowing the contact member to escape from the sheet contact surface, and prevents the leading edge of the sheet from getting caught in the groove portion, thereby suppressing the occurrence of feeding failures.

[0079] (Aspect 6) In any of aspects 1 to 5, at least the contact surface of a contact member such as relay member 40 that contacts a sheet such as a document is composed of a friction member 41 that has a higher frictional force with the sheet than the sheet contact surface of a sheet loading section such as movable document table 111. According to this, as described in the second variant, the bottom sheet of a stack of sheets loaded on a sheet stacking section such as the movable document table 111 can be prevented from being transported together with the top sheet by the frictional force with the friction member 41.

[0080] (Aspect 7) In an image reading device having a feeding section such as a document setting section A and an image reading section that reads an image on a document sheet fed from the feeding section, the feeding device according to any one of aspects 1 to 6 was used as the feeding section. This can prevent feeding failures.

[0081] (Aspect 8) In an image forming apparatus equipped with a feeding section such as a paper feed section 2 or a manual paper feed section, and an image forming section that forms an image on a sheet fed from the feeding section, a feeding device according to any one of aspects 1 to 7 was used as the feeding section. This can prevent feeding failures. [Explanation of symbols]

[0082] 1: Copy machine 2:Paper feed section 3: Image forming section 10: Main unit control section 11:Operation section 11a: Shaft mounting part 11b: Shaft mounting part 17: Side fence 21: Feeding cassette 22: Feeding cassette 23:Feeding means 40: Relay parts 40a: Rotating shaft part 40b: Rotating shaft part 40c: Insertion hole 40d: Base 41: Friction material 42: Hook part 80: Pickup roller 100:ADF 110:Document stack 111: Movable manuscript table 111a:Protrusion 111b: Mounting groove 111c: Hook part 112: Manuscript table 120: Paper feed belt 121: Reverse roller 140: Lifting plate 150: Controller 151: Document abutment surface 151a: Groove 152: Manuscript pre-separation section 153:Friction plate A: Document loading area B: Separation feeding section C: Resist part D: Turn section E: First reading and conveying section F: Second reading and conveying section G: Paper ejection section H: Stack section MS: Manuscript [Prior art documents] [Patent documents]

[0083] [Patent Document 1] Special Publication No. 7-33264

Claims

1. a sheet stacking section for stacking sheets and having at least a downstream end portion in a sheet conveying direction movable up and down; a sheet contact surface with which the leading edge of the sheet stacked in the sheet stacking section comes into contact, The sheet feeding device further comprises a contact member provided on the sheet stacking portion for contacting the sheet contact surface.

2. 2. The feeding device according to claim 1, a pair of side fences for positioning a widthwise center of the sheet at a widthwise center of the sheet stacking portion, The sheet feeding device according to claim 1, wherein the contact member is provided at a central portion of the sheet stacking portion in the width direction.

3. 2. The feeding device according to claim 1, the sheet contact surface has an inclined surface that is inclined upward from an upper end of the sheet contact surface toward a downstream side in a sheet conveying direction, The sheet feeding device according to claim 1, wherein the contact member contacts the inclined surface when a downstream end of the sheet stacking portion in a sheet transport direction is raised by a predetermined amount or more.

4. 2. The feeding device according to claim 1, The sheet feeding device according to claim 1, wherein the contact member is rotatably attached to the sheet stacking portion.

5. 2. The feeding device according to claim 1, The feeding device, wherein the contact member is made of an elastic member.

6. 2. The feeding device according to claim 1, 2. A sheet feeding device, comprising: a contact surface of the contact member that contacts the sheet, the contact surface being made of a friction member that exerts a higher frictional force with the sheet than a sheet contact surface of the sheet stacking portion.

7. A feeding section; an image reading unit that reads an image on the original sheet fed from the feeding unit, 2. An image reading apparatus, comprising: the feeding device according to claim 1 as said feeding section.

8. A feeding section; an image forming apparatus including an image forming unit that forms an image on the sheet fed from the feeding unit, 2. An image forming apparatus, comprising: the feeding device according to claim 1 as said feeding section.

Images