Sheet feeding device and image forming apparatus

Abstract

To accurately execute a feeding operation even for a small size document.SOLUTION: A sheet feeding device includes a feeding unit having: an arm; a feeding roller 17 rotatably supported by the arm; a feeding clutch 25 that switches connection and disconnection of a driving force transmitted from a drive source to the feeding roller 17; and a stopper pressing part 19 that presses a stopper 10 against a biasing force. The feeding unit 21 is made movable up and down by driving the drive source to elevate and lower the arm so that the feeding roller 17 contacts and separates from the uppermost document supported by a document tray, when the arm is lowered to bring the feeding roller 17 into contact with the uppermost document supported by the document tray, the stopper pressing part 19 presses the stopper 10 so that the stopper 10 is positioned in an allowable position. The stopper pressing part 19 is arranged between the feeding roller 17 and the feeding clutch 25 in a width direction orthogonal to a feeding direction.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a sheet feeding device for feeding sheets and an image forming apparatus using the same.

Background Art

[0002] Conventionally, an image reading device that can read image information of a document being fed while automatically feeding documents (sheets) stacked on a document tray or the like one by one has been used. As a sheet feeding device used in the image reading device, an ADF (Auto Document Feeder) that automatically feeds documents has become widespread. In this type of sheet feeding device, the leading edge of the document is abutted against a stopper and placed on the document tray, and in this state, the document is detected by a detection sensor. Then, the document is fed by the rotation of the feeding roller, and when a plurality of sheets are fed, they are separated one by one by a separation roller (see Patent Document 1). In this sheet feeding device, the configuration of the stopper is advantageous in terms of cost and downsizing of the device because the number of component parts is small. Further, as a configuration of the feeding unit of the sheet feeding device, in addition to the above-described feeding roller, detection sensor, separation roller, and stopper, a stopper pressing unit that releases the stopper during feeding and a clutch that controls the driving of the feeding roller and the separation roller are provided. These are arranged in the order of the clutch, the feeding roller and the separation roller, the stopper and the stopper pressing unit, and the detection sensor in the main scanning direction (width direction) of the document (see FIG. 7).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, image reading devices have been required to feed documents of various sizes. Among these, there is a demand for sheet feeding devices in image reading devices that can feed small documents such as business card-sized documents. In order to feed small documents, it is necessary to shorten the distance between the detection sensor, the feeding roller, and the stopper and stopper pressing part in the main scanning direction (width direction) of the document.

[0005] However, in the sheet feeding device described in Patent Document 1, the clutch, feeding roller and separation roller, stopper and stopper pressing part, and detection sensor are arranged in that order. Furthermore, the feeding roller and separation roller need to be positioned at the feeding center. For this reason, it is difficult to position the detection sensor, feeding roller and stopper within the limited main scanning direction range of small-sized documents. As a result, for documents with a short length in the main scanning direction, such as business card size, the detection sensor, stopper, feeding roller and separation roller may not be positioned correctly, potentially hindering their intended function. Consequently, there was a risk that the detection, feeding, and separation of small-sized documents could not be performed accurately.

[0006] The present invention aims to provide a sheet feeding device and an image forming apparatus that can accurately perform feeding operations even for small-sized documents. [Means for solving the problem]

[0007] The sheet feeding device of the present invention comprises a support portion for supporting a sheet, a drive source, a stopper movable between a restricting position in which the sheet supported by the support portion contacts and restricts the feeding of the sheet, and an allowable position in which the feeding of the sheet supported by the support portion is permitted, a biasing means for biasing the stopper to be in the restricting position, a vertically movable arm, a feeding rotating body rotatably supported by the arm and feeding the uppermost sheet supported by the support portion, a clutch for switching the connection and disconnection of the driving force transmitted from the drive source to the feeding rotating body, and a means for moving the stopper against the biasing force of the biasing means. The feeding unit comprises a feeding unit having a stopper pressing portion for pressing, wherein the feeding unit is capable of moving up and down so that the feeding rotating body approaches and moves away from the uppermost seat supported by the support portion by raising and lowering the arm driven by the drive source, and when the arm is lowered and the feeding rotating body comes into contact with the uppermost seat supported by the support portion, the stopper pressing portion presses the stopper to position the stopper in the allowable position, and the stopper pressing portion is positioned between the feeding rotating body and the clutch in the width direction perpendicular to the feeding direction of the sheet.

[0008] Furthermore, the image forming apparatus of the present invention is characterized by comprising the above-mentioned sheet feeding device, an image reading unit that reads an image of a sheet fed by the sheet feeding device, and an image forming unit that forms an image on a recording material based on the image read by the image reading unit. [Effects of the Invention]

[0009] According to the present invention, feeding operations can be accurately performed even for small-sized documents. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing a document reading device according to an embodiment. [Figure 2] This is a cross-sectional view showing a document reading device according to an embodiment. [Figure 3] This is a plan view showing a document reading device according to an embodiment. [Figure 4] This is a cross-sectional view showing the main part of the document feeding device according to the embodiment. [Figure 5] This is a side view showing the main parts of the document feeding device according to the embodiment. [Figure 6] This is a side view showing the stopper pressing portion according to the embodiment. [Figure 7] This is a schematic diagram showing a document feeding device related to a comparative example. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to Figures 1 to 6. In this embodiment, a case in which a document reading device 1 equipped with a sheet feeding device is mounted on an image forming apparatus 100 will be described. This image forming apparatus 100 includes an image forming unit 101 that forms an image on a recording material based on the image read by the document reading device 1.

[0012] [Document scanning device] Figure 1 is a perspective view of the document reading device 1 according to this embodiment, Figure 2 is a cross-sectional view of the document reading device 1, and Figure 3 is a plan view of the document reading device 1. In this embodiment, the main scanning direction (width direction) perpendicular to the document feeding direction of the document reading device 1 is the front-to-back direction. The document reading device 1, which is an example of an image reading unit, includes a document feeding device 20, which is an example of a sheet feeding device, and a document scanner 50. The document scanner 50 is a document scanning type document reading device that can read a document placed on the document glass, and includes a housing 51 and a first reading unit 52. The first reading unit 52 irradiates light from an LED array as a light source onto the image information surface of the document D1, and reads the image information by imaging the reflected light reflected from the image information surface onto a sensor element with a SELFOC® lens. That is, the document reading device 1 reads the image of the document fed by the document feeding device 20.

[0013] [Original feeding device] The document feeder 20 is an ADF (Automatic Document Feeder) and includes a document tray 4 on which a document, which is an example of a sheet, is placed, and a document feeder unit 21, etc. The document tray 4 is an example of a support part that supports the document. As shown in Figure 2, the document feeder 20 has a roughly U-shaped U-turn path 7 (document feed path). The U-turn path 7 is formed by an upper guide surface 7a that contacts the upper surface of the document to guide the document, and a lower guide surface 7b that contacts the lower surface of the document to guide the document. The U-turn path 7 is provided with a separation roller 8 and a separation pad 9, which are examples of a separation rotating body, and a stopper 10 that restricts the leading edge position of the document D1. The U-turn path 7 is also provided with a feed roller 17 that contacts the uppermost of the stacked documents D1 to pick it up, and a document presence sensor 11 that detects the presence or absence of documents D1. The U-turn path 7 is also provided with transport rollers 13, 14 and an discharge roller 15 for transporting the documents D1, and an edge sensor 16 that detects the leading edge and trailing edge of the documents D1, etc.

[0014] The stopper 10 is provided to move between a restricting position in which a document supported by the document tray 4 comes into contact with the stopper and restricts the feeding of the document, and an allowable position in which the feeding of the document supported by the document tray 4 is permitted. When the stopper 10 is in the restricting position, it protrudes upward from below the U-turn path 7 through a hole provided in the lower guide surface 7b. On the other hand, when the stopper 10 is in the allowable position, it is located below the lower guide surface 7b and is therefore retracted from the U-turn path 7. A biasing spring 12 is also provided, which is an example of a biasing means for biasing the stopper 10 to be in the restricting position. In this embodiment, the stopper 10 is positioned such that the restricting position is upper and the allowable position is lower, and it moves to the allowable position by being pushed downward from the restricting position by the stopper pressing part 19, which will be described later. However, the upper and lower relationship between the restricting position and the allowable position of the stopper 10 is not limited to this and may be reversed.

[0015] An example of the detection unit, the document presence sensor 11, has a detection section for detecting a document. This detection section is disposed on the opposite side of the stopper 10 sandwiching the feed roller 17 in the main scanning direction. Further, the detection position of the detection section is disposed upstream of the stopper 10 in the feed direction, and detects the presence or absence of a document supported on the document tray 4.

[0016] The document feeding device 20 has a feeding unit 21. As shown in FIG. 4, the feeding unit 21 has a liftable arm 21a, a feed roller 17, a separation roller 8, a feed clutch 25, and a separation clutch 26. The feed roller 17 is an example of a feed rotating body, is rotatably supported by the arm 21a, and feeds the uppermost document supported on the document tray 4. Further, the feeding unit 21 has a stopper pressing section 19 that presses the stopper 10 against the biasing force of the biasing spring 12.

[0017] The document feeding device 20 is provided with a second reading unit 18. Similar to the first reading unit 52, the second reading unit 18 irradiates light from an LED array as a light source onto the image information surface of the document D1, and forms an image of the reflected light reflected by the image information surface on a sensor element with a Selfoc (registered trademark) lens to read image information. In the document feeding device 20 of the present embodiment, when the user places the document D1 on the document tray 4 and the sub tray 5, the leading end position of the document D1 is regulated by the stopper 10, and the document presence sensor 11 detects that the document D1 is present.

[0018] When the user instructs the start of reading from the operation unit, a drive motor (not shown), which is an example of a drive source, rotates. As a result, the feeding unit 21 descends, and the stopper pressing portion 19 descends. Thereby, the stopper 10 is pushed down, and the original document D1 is fed by the feeding roller 17. That is, the feeding unit 21 can move up and down the feeding roller 17 so as to contact and separate from the uppermost original document placed on the original document tray 4 by moving the arm 21a up and down by driving the drive motor. When the feeding unit 21 lowers the arm 21a and brings the feeding roller 17 into contact with the uppermost original document, the stopper pressing portion 19 presses the stopper 10 to position the stopper 10 at the allowable position.

[0019] Due to the rotation of the feeding roller 17, the original document D1 is fed to the separation portion of the separation roller 8 and the separation pad 9, the original document D1 is separated one by one, and the uppermost original document D1 is separated and fed. Further, the separated original document D1 is fed along the U-turn path 7 by the conveying roller 13 and conveyed to the reading portions of the first reading unit 52 and the second reading unit 18.

[0020] When the leading end portion of the original document D is detected by the edge sensor 16, reading of the image information on the surface of the original document D1 is started by the first reading unit 52 at a position conveyed a predetermined amount from that position, and reading of the image information on the back surface of the original document D1 is started by the second reading unit 18. After the start of reading, the original document heads toward the conveying roller 14. Then, when the trailing end portion of the original document D1 is detected by the edge sensor 16, reading of the image information by the first reading unit 52 and the second reading unit 18 is terminated at a position conveyed a predetermined amount from that position. Then, the original document D1 is discharged to the discharge tray 24 by the discharge roller 15. In this way, in the original document feeding device 20, the above-described reading operation is repeated until the original document presence / absence sensor 11 detects the absence of an original document.

[0021] [Original document tray] The document tray 4 will be explained using Figures 2 and 3. Figure 3 is a plan view of the document feeder 20. The document feeder 20 has a document tray 4 for loading documents. The document tray 4 has a pair of document regulating plates 30 and 31 that can contact both sides of a document in order to restrict the position of the set document in the main scanning direction to the feed center. The document regulating plates 30 and 31 are connected by a gear train (not shown), and when one document regulating plate is moved, the other document regulating plate also moves in conjunction. For example, when document regulating plate 30 is moved in direction B in Figure 3, document regulating plate 31 moves in direction C. The amount of movement of the document regulating plates 30 and 31 is always the same, making it possible to restrict the document to the feed center regardless of the width of the document.

[0022] In the center of the document tray 4, there are inspection windows 41 and 42 to allow the user to check the small-sized documents loaded in the output tray 24. By making it easier to check the upstream side of the output tray 24 using the inspection windows 41 and 42, it is possible to prevent small-sized documents such as business card size or A6R size from being forgotten in the output tray 24.

[0023] A sub-tray 5 is provided upstream of the document tray 4. The sub-tray 5 has a rotating part 5b and is rotatable relative to the document tray 4. The presence of the sub-tray 5 makes it possible to support documents that are long in the feeding direction. In addition, because the sub-tray 5 is rotatable, it can be closed so that it overlaps the document tray 4. This improves the visibility and ease of removal of documents discharged into the output tray 24, and by covering the document feed opening, it is possible to prevent dust and other foreign matter from accumulating on the document tray 4 and entering the U-turn path 7 when not in use.

[0024] [Feeding Unit] The configuration of the feeding unit 21, including the stopper pressing portion 19, which is a feature of the present invention, will be described in detail below with reference to Figures 4 to 6. Figure 5 is a view of the feeding unit 21 from the direction of arrow A in Figure 3.

[0025] The feeding unit 21 includes a feeding clutch 25, which is an example of a clutch that switches between connecting and disconnecting the driving force transmitted from the drive source to the feeding roller 17, and a feeding shaft 27 that connects the feeding roller 17 and the feeding clutch 25. The feeding unit 21 also includes a separation clutch 26 that switches between connecting and disconnecting the driving force transmitted from the drive source to the separation roller 8, and a separation shaft 28 that connects the separation roller 8 and the separation clutch 26. In this embodiment, the feeding clutch 25 is arranged coaxially with the feeding roller 17, and the separation clutch 26 is arranged coaxially with the separation roller 8.

[0026] In the feeding unit 21, the stopper pressing section 19 is positioned between the feeding roller 17 and the feeding clutch 25 in the main scanning direction. That is, in the configuration of the feeding unit 21 of this embodiment, the feeding roller 17 is provided in the center in the main scanning direction. A document presence / absence sensor 11 is positioned to the right of the feeding roller 17 in the feeding direction, and a feeding clutch 25 and a separation clutch 26 are provided on the left side of the feeding roller 17 in the feeding direction, opposite the document presence / absence sensor 11. Furthermore, the stopper pressing section 19 is provided between the feeding roller 17 and the feeding clutch 25 and separation clutch 26, and a stopper 10 is positioned below the stopper pressing section 19.

[0027] The stopper pressing portion 19 is mounted so as to be supported across the feed shaft 27 and the separation shaft 28. The stopper pressing portion 19 has a first fitting portion 19a that is detachably attached to the feed shaft 27, a second fitting portion 19b that is detachably attached to the separation shaft 28, and a connecting portion 19c that bridges and connects the first fitting portion 19a and the second fitting portion 19b. The connecting portion 19c has a flat portion 19d that faces the stopper 10, and the flat portion 19d presses the stopper 10 downward when the arm 21a is lowered. Note that the first fitting portion 19a and the second fitting portion 19b are not limited to being directly detachable from the feed shaft 27 and the separation shaft 28, but may be indirectly detachable via shaft covers provided on the feed shaft 27 and the separation shaft 28. As described above, the stopper pressing part 19 is detachable from the feeding unit 21, making installation easy and allowing for easy removal and reinstallation during maintenance.

[0028] Next, the effects of this embodiment will be described. Figure 7 shows a schematic diagram of the comparative example's feeding unit 121 viewed from the front. As shown in Figure 7, with respect to the main scanning direction, a feeding roller 117 is located in the center, a stopper 10 is located to the right in the feeding direction, and a document presence sensor 11 is located to the right of the stopper 10, away from the feeding roller 117. A stopper pressing part 119 is also provided on the outside of the arm 121a of the feeding unit 121. The feeding clutch 125 is located adjacent to the feeding roller 117. However, in this case, since the document presence sensor 11 is located outside the main scanning width of the small-sized document D2, there is a risk that the document presence sensor 11 may not be able to detect the document D2.

[0029] In contrast, in this embodiment, as shown in Figure 5, the document presence sensor 11 is positioned on the right side of the feed roller 17 in the feed direction, and the stopper pressing section 19 is provided on the left side of the feed roller 17 in the feed direction, opposite the document presence sensor 11. Furthermore, in this embodiment, with respect to the main scanning direction, the distance from the feed center to the document presence sensor 11 is set to be less than or equal to the distance from the feed center to the stopper 10. Moreover, in this embodiment, an example of a small-sized document is a business card, and with respect to the main scanning direction, the distance from the feed center to the stopper 10 is set to be less than or equal to half the size of the business card. In this embodiment, the size of a business card is a document with a length of 55 [mm] in the main scanning direction and a length of 91 [mm] in the sub-scanning direction. In other words, the distance from the transport center to the stopper 10 in the main scanning direction is set to be 22.5 [mm] or less. This allows the feed roller 17, stopper 10, and document presence sensor 11 to be efficiently positioned within the main scanning direction of the document width of a small-sized document, enabling reliable detection and feeding / separation of small-sized documents.

[0030] As described above, in the document feeding device 20 of this embodiment, the document presence sensor 11 and the stopper pressing unit 19 are provided on either side of the feeding roller 17 in the main scanning direction. This allows for accurate feeding operations even for small-sized documents. In other words, according to this embodiment, the document presence sensor 11, the feeding roller 17, the stopper 10, and the stopper pressing unit 19 can be arranged within the range of the main scanning direction of small-sized documents. Therefore, the components necessary for detecting, feeding, and separating documents can be efficiently arranged in the main scanning direction of small-sized documents, resulting in a configuration that can reliably detect, feed, and separate small-sized documents.

[0031] Furthermore, in the document feeding device 20 of this embodiment, the feeding clutch 25 is arranged coaxially with the feeding roller 17, and at least a portion of the stopper pressing part 19 is also arranged coaxially with the feeding roller 17. As a result, accurate feeding operations can be performed even for small-sized documents with a simple configuration.

[0032] In addition, the document feeding device 20 of this embodiment described above has been configured such that the document presence sensor 11 is located on the right side of the feeding roller 17 in the feeding direction, and the stopper pressing part 19 is located on the left side of the feeding roller 17 in the feeding direction. However, it is not limited to this configuration. For example, the left and right sides may be reversed, with the document presence sensor 11 located on the left side of the feeding roller 17 in the feeding direction, and the stopper pressing part 19 located on the right side of the feeding roller 17 in the feeding direction.

[0033] Furthermore, in the document feeding device 20 of this embodiment, the feeding clutch 25 is arranged coaxially with the feeding roller 17 and the separation clutch 26 is arranged coaxially with the separation roller 8, but this is not the only case. For example, the feeding clutch 25 and the feeding roller 17 may be on separate axes, and similarly, the separation clutch 26 and the separation roller 8 may be on separate axes.

[0034] Furthermore, although the document feeding device 20 of this embodiment has been described as being mounted so as to be supported across the feeding shaft 27 and the separation shaft 28, it is not limited to this. For example, the stopper pressing part may be supported by only one shaft, or it may be provided on the arm 21a.

[0035] Furthermore, in the document feeding device 20 of this embodiment, a feeding roller 17 is used as an example of a feeding rotating body, and a separating roller 8 is used as an example of a separating rotating body, but this is not limited to these. A rotating belt or the like may be used instead of rollers in either case.

[0036] Furthermore, although the document feeding device 20 of this embodiment has been described in the case where it is applied to the document reading device 1, it is not limited to this and can be applied to sheet feeding devices in general. [Explanation of symbols]

[0037] 1…Document reading device (image reading unit), 4…Document tray (support unit), 8…Separation roller (separation rotating body), 10…Stopper, 11…Document presence sensor (detection unit), 12…Biasing spring (biasing means), 17…Feeding roller (feeding rotating body), 19…Stopper pressing part, 19a…First fitting part, 19b…Second fitting part, 19c…Connecting part, 19d…Flat part, 20…Document feeding device (sheet feeding device), 21…Feeding unit, 21a…Arm, 25…Feeding clutch (clutch), 26…Separation clutch, 27…Feeding shaft, 28…Separation shaft, 100…Image forming device, 101…Image forming unit, D1, D2…Document (sheet)

Claims

1. a support portion that supports the seat; A driving source; a stopper that is movable between a restricting position where the sheet supported by the support portion comes into contact with the stopper to restrict feeding of the sheet and a permitting position where the sheet supported by the support portion is permitted to be fed; a biasing means for biasing the stopper so that it is positioned at the restriction position; a feeding unit including a liftable arm, a feeding rotor rotatably supported by the arm and configured to feed the uppermost sheet supported by the support section, a clutch that switches between connection and disconnection of a driving force transmitted from the driving source to the feeding rotor, and a stopper pressing section that presses the stopper against the biasing force of the biasing means, the feeding unit is capable of raising and lowering the arm by being driven by the drive source, so that the feeding rotor can be brought into contact with and separated from the uppermost sheet supported by the support portion, and when the arm is lowered to bring the feeding rotor into contact with the uppermost sheet supported by the support portion, the stopper pressing portion presses the stopper to position the stopper at the allowable position; the stopper pressing portion is disposed between the feeding rotor and the clutch in a width direction perpendicular to a sheet feeding direction; A sheet feeding device characterized by:

2. the clutch is disposed coaxially with the feeding rotor, At least a portion of the stopper pressing portion is arranged coaxially with the feeding rotor.

2. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.

3. a detection unit having a detection portion that detects a sheet; the detection unit is disposed on the opposite side of the stopper across the feeding rotor in the width direction.

3. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.

4. the detection unit has a detection position disposed upstream of the stopper in the feeding direction, and detects the presence or absence of a sheet supported by the support unit.

4. The sheet feeding device according to claim 3, wherein the sheet feeding device is a sheet feeding device.

5. a distance from a sheet feeding center to the detection unit in the width direction is equal to or less than a distance from the sheet feeding center to the stopper; 5. The sheet feeding device according to claim 3, wherein the sheet feeding device is a sheet feeding device.

6. the clutch is a feed clutch, the feeding unit includes a separation rotor that separates the sheets one by one when a plurality of sheets are fed by the feeding rotor; a separation clutch that switches between connection and disconnection of a driving force transmitted from the driving source to the separation rotor; a feeding shaft that connects the feeding rotor and the feeding clutch; and a separation shaft that connects the separation rotor and the separation clutch; the stopper pressing portion is attached so as to be supported across the feeding shaft and the separation shaft; 6. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.

7. the stopper pressing portion has a first fitting portion detachably attached to the feed shaft, a second fitting portion detachably attached to the separation shaft, and a connecting portion that connects the first fitting portion and the second fitting portion and has a flat portion facing the stopper, The connecting portion presses the stopper when the arm is lowered.

7. The sheet feeding device according to claim 6, wherein the sheet feeding device is a sheet feeding device.

8. The stopper is pushed downward from the restricting position by the stopper pressing portion, and thereby moves to the allowing position.

8. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.

9. the sheet supported by the support portion is a business card size, a distance from a sheet feeding center to the stopper in the width direction is equal to or less than half the size of a business card; 9. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.

10. The sheet feeding device according to any one of claims 1 to 9, an image reading unit that reads an image on a sheet fed by the sheet feeding device; an image forming unit that forms an image on a recording material based on the image read by the image reading unit, An image forming apparatus characterized by:

Images