JP7686510B2 - Sheet feeding device and image forming apparatus - Google Patents

Description

The present invention relates to a sheet feeding device that feeds sheets and an image forming apparatus that uses the same.

Conventionally, image reading devices have been used that can read image information of documents (sheets) loaded on a document tray or the like while automatically feeding the documents one by one. As a sheet feeding device used in an image reading device, an ADF (Auto Document Feeder) that automatically feeds documents is widely used. In this type of sheet feeding device, the leading edge of the document is placed on the document tray with abutting it against a stopper, and the document is detected by a detection sensor in this state. Then, the document is fed by the rotation of the feed roller, and when multiple sheets are fed, they are separated one by one by a separation roller (see Patent Document 1). In this sheet feeding device, the stopper is configured with a small number of components, which is advantageous in terms of cost and size reduction of the device. Furthermore, as a configuration of the feeding section of the sheet feeding device, in addition to the above-mentioned feed roller, detection sensor, separation roller, and stopper, a stopper pressing section that releases the stopper during feeding, and a clutch that controls the drive of the feed roller and separation roller are provided. These are arranged in the main scanning direction (width direction) of the document in the following order: clutch, feed roller and separation roller, stopper and stopper pressing part, and detection sensor (see Figure 7).

JP 2017-007790 A

In recent years, there has been a demand for image reading devices to be able to feed documents of various sizes. Among these, there is a demand for a sheet feeding device for an image reading device that can feed documents of small sizes such as business cards. In order to feed small-sized documents, it is necessary to shorten the distance between the detection sensor, the feed roller, the stopper, and the stopper pressing portion in the main scanning direction (width direction) of the document.

However, in the sheet feeding device described in Patent Document 1, the clutch, the feed roller, the separation roller, the stopper, the stopper pressing portion, and the detection sensor are arranged in this order. Furthermore, the feed roller and the separation roller need to be arranged at the center of feeding. For this reason, it is difficult to arrange the detection sensor, the feed roller, and the stopper within the limited range of the main scanning direction of a small-sized original. As a result, for an original that is short in the main scanning direction, such as a business card-sized original, the detection sensor, the stopper, the feed roller, and the separation roller are not arranged in the appropriate positions, which may impede their original functions. Therefore, there is a risk that the original detection, feeding, and separation cannot be performed accurately for small-sized originals.

The present invention aims to provide a sheet feeding device and an image forming device that can accurately perform feeding operations even for small-sized documents.

The sheet feeding device of the present invention includes a support section for supporting a sheet, a drive source, a stopper that can be moved between a restricting position where the sheet supported on the support section abuts against the stopper to restrict feeding of the sheet and an allowing position where the sheet supported on the support section is allowed to be fed, a biasing means for biasing the stopper to be positioned at the restricting position, a liftable arm, a feeding rotor that is rotatably supported on the arm and feeds the topmost sheet supported on the support section, a clutch that switches between connection and disconnection of a driving force transmitted from the drive source to the feeding rotor, and a stopper that is movable against the biasing force of the biasing means. and a feed unit having a stopper pressing portion that presses the stopper against the uppermost sheet supported by the support portion, the feed unit is capable of raising and lowering the arm by driving the drive source to raise and lower the feed rotor so as to move it toward and away from the uppermost sheet supported by the support portion, and when the arm is lowered to bring the feed 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, and the stopper pressing portion is disposed between the feed rotor and the clutch in the width direction perpendicular to the sheet feed direction.

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 on the 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.

According to the present invention, feeding operations can be performed accurately even for small-sized documents.

1 is a perspective view showing a document reading device according to an embodiment; 1 is a cross-sectional view showing a document reading device according to an embodiment. 1 is a plan view showing a document reading device according to an embodiment; 1 is a cross-sectional view showing a main part of a document feeding device according to an embodiment. 1 is a side view showing a main part of a document feeding device according to an embodiment; FIG. 4 is a side view showing the stopper pressing portion according to the embodiment. FIG. 1 is a schematic diagram showing a document feeding device according to a comparative example.

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

[Document reading device]
FIG. 1 is a perspective view of the document reading device 1 according to the present embodiment, FIG. 2 is a cross-sectional view of the document reading device 1, and FIG. 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-rear direction. The document reading device 1, which is an example of an image reading unit, has a document feeding device 20, which is an example of a sheet feeding device, and a document table scanner 50. The document table scanner 50 is a document table scanning type document reading device capable of reading a document placed on a document table glass, and has 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 forms an image of the reflected light reflected from the image information surface on a sensor element using a SELFOC (registered trademark) lens to read image information. That is, the document reading device 1 reads the image of the document fed by the document feeding device 20.

[Original feeding device]
The document feeder 20 is an ADF, and includes a document tray 4 on which documents, which are an example of sheets, are placed, and a feed unit 21. The document tray 4 is an example of a support portion that supports documents. As shown in FIG. 2, the document feeder 20 has a U-turn path 7 (document feed path) that is substantially U-shaped. The U-turn path 7 is formed of 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 that are examples of a separation rotating body, and a stopper 10 that regulates the leading end position of the document D1. The U-turn path 7 is also provided with a feed roller 17 that contacts the topmost document D1 among the stacked documents to pick it up, and a document presence/absence sensor 11 that detects the presence or absence of the document D1. The U-turn path 7 is also provided with transport rollers 13 and 14 for transporting the document D1, a discharge roller 15, an edge sensor 16 for detecting the leading and trailing ends of the document D1, and the like.

The stopper 10 is provided so as to be movable between a restricting position where the document supported on the document tray 4 comes into contact with the stopper 10 to restrict the feeding of the document, and an allowable position where the document supported on the document tray 4 is allowed to be fed. 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 in a state of being withdrawn from the U-turn path 7. In addition, a biasing spring 12 is provided as an example of a biasing means for biasing the stopper 10 to be located at the restricting position. In this embodiment, the stopper 10 is configured so that the restricting position is at the top and the allowable position is at the bottom, and is moved to the allowable position by being pushed downward from the restricting position by the stopper pressing portion 19 described later. However, the vertical relationship between the restricting position and the allowable position of the stopper 10 is not limited to this, and may be reversed.

The document presence sensor 11, which is an example of a detection unit, has a detection section that detects documents. This detection section is disposed on the opposite side of the stopper 10 across the feed roller 17 in the main scanning direction. The detection section is also disposed with its detection position upstream of the stopper 10 in the feed direction, and detects the presence or absence of documents supported on the document tray 4.

The document feeder 20 has a feed unit 21. As shown in FIG. 4, the feed 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 rotor, and is rotatably supported by the arm 21a to feed the topmost document supported on the document tray 4. The feed unit 21 also has a stopper pressing portion 19 that presses the stopper 10 against the biasing force of the biasing spring 12.

The document feeder 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 the light reflected from the image information surface is focused on a sensor element by a SELFOC (registered trademark) lens to read the image information. In the document feeder 20 of this embodiment, when a user places the document D1 on the document tray 4 and the sub-tray 5, the leading edge position of the document D1 is restricted by the stopper 10, and the document presence sensor 11 detects the presence of the document D1.

When the user issues an instruction to start reading from the operation unit, a drive motor (not shown), which is an example of a drive source, rotates. This causes the feeding unit 21 to descend, and the stopper pressing unit 19 to descend. This causes the stopper 10 to be pressed down, and the feeding roller 17 feeds the document D1. That is, the feeding unit 21 can raise and lower the arm 21a driven by the drive motor to raise and lower the feeding roller 17 so as to move it toward and away from the topmost document placed on the document tray 4. Then, when the feeding unit 21 lowers the arm 21a to bring the feeding roller 17 into contact with the topmost document, the stopper pressing unit 19 presses the stopper 10 to position the stopper 10 in the allowable position.

By rotating the feeding roller 17, the document D1 is fed to the separation section between the separation roller 8 and the separation pad 9, where the document D1 is separated one by one, and the topmost document D1 is separated and fed. In addition, the separated document D1 is fed along the U-turn path 7 by the transport roller 13, and is transported to the reading section of the first reading unit 52 and the second reading unit 18.

When the edge sensor 16 detects the leading edge of the document D1, the first reading unit 52 starts reading image information on the front side of the document D1 at a location transported a predetermined distance from that position, and the second reading unit 18 starts reading image information on the back side of the document D1. After reading starts, the document heads toward the transport rollers 14. Then, when the edge sensor 16 detects the trailing edge of the document D1, the first reading unit 52 and the second reading unit 18 stop reading image information at a location transported a predetermined distance from that position. The document D1 is then discharged to the discharge tray 24 by the discharge rollers 15. In this way, the document feeder 20 repeats the above-mentioned reading operation until the document presence/absence sensor 11 detects that no document is present.

[Original Tray]
The document tray 4 will be described with reference to Figs. 2 and 3. Fig. 3 is a plan view of the document feeder 20. The document feeder 20 has a document tray 4 for stacking documents. The document tray 4 has a pair of document regulating plates 30, 31 that can abut on both sides of the document in order to regulate the position of the document in the main scanning direction to the feeding center. The document regulating plates 30, 31 are connected by a gear train (not shown), and when one document regulating plate is operated, the other document regulating plate also operates in conjunction with it. For example, when the document regulating plate 30 is operated in the B direction in Fig. 3, the document regulating plate 31 moves in the C direction. The document regulating plates 30, 31 always move by the same amount, and it is possible to regulate the document to the feeding center regardless of the document width.

In the center of the document tray 4, confirmation windows 41 and 42 are provided so that the mainly small-sized documents loaded on the discharge tray 24 can be confirmed. By making it easier to confirm the upstream side of the discharge tray 24 through the confirmation windows 41 and 42, it is possible to prevent forgetting to remove small-sized documents such as business card size or A6R size from the discharge tray 24.

A sub-tray 5 is provided upstream of the document tray 4. The sub-tray 5 has a rotating portion 5b and is rotatable relative to the document tray 4. The provision 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, the sub-tray 5 can be closed so that it overlaps the document tray 4. This improves the visibility and ease of removal of documents discharged to the discharge tray 24, and by covering the document feed opening, it is possible to prevent foreign matter such as dust from accumulating and entering on the document tray 4 or inside the U-turn path 7 when not in use.

[Feed 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 as viewed from the direction of arrow A in Figure 3.

The feed unit 21 has a feed clutch 25, which is an example of a clutch that switches between connection and disconnection of the driving force transmitted from the drive source to the feed roller 17, and a feed shaft 27 that connects the feed roller 17 and the feed clutch 25. The feed unit 21 also has a separation clutch 26 that switches between connection and disconnection of 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 feed clutch 25 is arranged coaxially with the feed roller 17, and the separation clutch 26 is arranged coaxially with the separation roller 8.

In the feeding unit 21, the stopper pressing portion 19 is disposed 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 in this embodiment, the feeding roller 17 is disposed in the center in the main scanning direction. Then, the document presence sensor 11 is disposed on the right side of the feeding roller 17 in the feeding direction, and the feeding clutch 25 and the separation clutch 26 are disposed on the left side of the feeding roller 17 in the feeding direction opposite the document presence sensor 11. Furthermore, the stopper pressing portion 19 is disposed between the feeding roller 17 and the feeding clutch 25 and the separation clutch 26, and the stopper 10 is disposed below the stopper pressing portion 19.

The stopper pressing portion 19 is attached 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, and may be indirectly detachable via a shaft cover provided on the feed shaft 27 and the separation shaft 28. In this way, the stopper pressing portion 19 is detachable from the feeding unit 21, which makes installation easy and allows it to be easily removed and reattached during maintenance, etc.

Next, the effect of this embodiment will be described. FIG. 7 shows a schematic diagram of a comparative example feeding unit 121 viewed from the front. As shown in FIG. 7, in the main scanning direction, a feeding roller 117 is provided in the center, a stopper 10 is provided on the right side in the feeding direction, and a document presence sensor 11 is provided on the right side away from the feeding roller 117. In addition, a stopper pressing portion 119 is provided on the outside of the arm 121a of the feeding unit 121. A feeding clutch 125 is provided adjacent to the feeding roller 117. However, in this case, since the document presence sensor 11 is disposed outside the main scanning width of the small-sized document D2, there is a risk that the document presence sensor 11 will not be able to detect the document D2.

In contrast, in this embodiment, as shown in FIG. 5, the document presence sensor 11 is disposed on the right side of the feed roller 17 in the feeding direction, and the stopper pressing portion 19 is provided on the left side of the feed roller 17 in the feeding direction opposite to the document presence sensor 11. In addition, in this embodiment, the distance from the feed center to the document presence sensor 11 in the main scanning direction is set to be equal to or less than the distance from the feed center to the stopper 10. Furthermore, in this embodiment, an example of a small-sized document is a business card, and the distance from the feed center to the stopper 10 in the main scanning direction is set to be equal to or less than half the business card size. In this embodiment, the business card size 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 equal to or less than 22.5 [mm]. 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 the small-sized document, making it possible to reliably detect, feed, and separate the small-sized document.

As described above, according to the document feeding device 20 of this embodiment, the document presence sensor 11 and the stopper pressing portion 19 are provided on either side of the feed roller 17 in the main scanning direction. This allows the feeding operation to be performed accurately even for small-sized documents. That is, according to this embodiment, it is possible to arrange the document presence sensor 11, the feed roller 17, the stopper 10, and the stopper pressing portion 19 within the range of the main scanning direction of the small-sized document. This allows the configuration required for efficient document detection, feeding, and separation to be arranged in the main scanning direction of the small-sized document, resulting in a configuration that allows for reliable document detection, feeding, and separation of small-sized documents.

In addition, according to the document feeder 20 of this embodiment, the feed clutch 25 is arranged coaxially with the feed roller 17, and at least a portion of the stopper pressing portion 19 is arranged coaxially with the feed roller 17. This makes it possible to accurately perform the feeding operation even for small-sized documents with a simple configuration.

The document feeder 20 of the present embodiment described above has been described as having the document presence sensor 11 provided on the right side in the feeding direction of the feed roller 17, and the stopper pressing unit 19 provided on the left side in the feeding direction of the feed roller 17, but this is not limited to the above. For example, the left and right may be reversed, with the document presence sensor 11 provided on the left side in the feeding direction of the feed roller 17, and the stopper pressing unit 19 provided on the right side in the feeding direction of the feed roller 17.

In addition, 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 limited to the above. For example, the feeding clutch 25 and the feeding roller 17 may be on different shafts, and similarly, the separation clutch 26 and the separation roller 8 may be on different shafts.

In addition, in the document feeder 20 of this embodiment, the stopper pressing portion 19 is attached so as to be supported across the feed shaft 27 and the separation shaft 28, but this is not limited to the above. For example, the stopper pressing portion may be supported by only one shaft, or may be provided on the arm 21a.

In addition, in the document feeding device 20 of this embodiment, the feeding roller 17 is used as an example of a feeding rotor, and the separation roller 8 is used as an example of a separation rotor, but this is not limited to this. In both cases, a rotating belt or the like may be used instead of a roller.

In addition, in the present embodiment, the document feeding device 20 has been described as being applied to the document reading device 1, but this is not limited thereto, and the document feeding device 20 can be applied to any sheet feeding device.

1...Document reading device (image reading section), 4...Document tray (support section), 8...Separation roller (separation rotor), 10...Stopper, 11...Document presence sensor (detection unit), 12...Spring (sprung means), 17...Feed roller (feed rotor), 19...Stopper pressing section, 19a...First fitting section, 19b...Second fitting section, 19c...Connecting section, 19d...Planar section, 20...Document feeding device (sheet feeding device), 21...Feeding unit, 21a...Arm, 25...Feed clutch (clutch), 26...Separation clutch, 27...Feed shaft, 28...Separation shaft, 100...Image forming device, 101...Image forming section, D1, D2...Document (sheet)

Claims (10)

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 as to be positioned at the regulating 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 configured to switch between connection and disconnection of a driving force transmitted from the driving source to the feeding rotor, and a stopper pressing section configured to press 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 driving source so as to bring the feeding rotor into contact with and away 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 permitted 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 comprising: The clutch is disposed coaxially with the feeding rotor,
At least a portion of the stopper pressing portion is disposed coaxially with the feeding rotor.
2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises: A detection unit having a detection portion that detects a sheet is provided,
The detection unit is disposed on the opposite side of the stopper across the feeding rotor in the width direction.
3. The sheet feeding apparatus according to claim 1, wherein the sheet feeding device is a sheet feeder. the detection portion has a detection position disposed upstream of the stopper in the feeding direction and detects the presence or absence of the sheet supported by the support portion.
4. The sheet feeding apparatus according to claim 3, With respect to the width direction, a distance from a feeding center of the sheet to the detection unit is equal to or less than a distance from the feeding center to the stopper.
5. The sheet feeding apparatus according to claim 3, wherein the sheet feeding device is a sheet feeder. 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 conveying device. 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 connecting the first fitting portion and the second fitting portion and having a flat portion facing the stopper,
The connecting portion presses the stopper when the arm is lowered.
7. The sheet feeding apparatus according to claim 6, 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 conveying device. The sheet supported by the support portion has a business card size,
With respect to the width direction, the distance from the sheet feeding center to the stopper is equal to or less than half the size of the business card.
9. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet conveying device. A 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,
1. An image forming apparatus comprising:

Images