JP6704715B2 - Sheet feeding apparatus and image forming apparatus - Google Patents

Description

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

In general, an image forming apparatus such as a printer includes a pickup roller that feeds sheets stacked on a sheet stacking unit such as a cassette or a manual feed tray. Conventionally, there has been proposed a paper transport unit that includes an arm that swingably supports a pickup roller around a rotation axis of the transport roller, and urges the arm with a spring to press the pickup roller against a sheet. Reference 1). When the sheet is not fed, the pickup roller moves the arm in the direction opposite to the biasing direction of the spring by the solenoid, and is held at the separated position separated from the sheets stacked on the sheet stacking unit.

JP-A-7-33284

If the points of action of the urging force acting on the arm by the spring and the force acting on the arm by the solenoid are separated, the arm is deformed and the pickup roller cannot be accurately positioned at the separated position. There is a problem.

In addition, in recent years, from the viewpoint of weight reduction, there is an increasing number of occasions where a resin shaft is used instead of the metal shaft that has been conventionally used for the transport roller shaft. Since resin is generally softer than metal, if a large load is applied to the arm arranged on the transport roller shaft, large bending deformation is likely to occur.

As a result, in order to reliably separate the pickup roller from the sheet, it is necessary to move the pickup roller in consideration of the amount of bending. When the movement amount of the pickup roller is increased, there are problems such as an increase in a collision sound with the tray when the pickup roller is lowered and an increase in the up/down time of the pickup roller.

Therefore, according to the present invention, a sheet feeding device and an image forming apparatus that solve the above-mentioned problems by arranging a first receiving portion and a second receiving portion, which receive the urging force of the urging means and the force of the moving means, respectively, in close proximity to each other. The purpose is to provide.

According to the present invention, in a sheet feeding device, a stacking unit that stacks sheets, a feeding rotating body that can feed the sheets stacked on the stacking unit, and a sheet that is fed by the feeding rotating body are conveyed. A transport rotator, a transport rotator shaft that rotatably supports the transport rotator, a separation rotator that is in pressure contact with the transport rotator, and separates sheets together with the transport rotator into sheets one by one. Holding means for holding the feeding rotating body so as to be able to move up and down, and for holding the feeding rotating body in contact with the sheets stacked on the stacking means, the holding means rotating about the transport rotating body axis. Urging means for urging the urging means, the urging means is disposed above the feeding rotating body and at a position overlapping the holding means in the axial direction of the conveying rotator axis, and resists the urging force of the urging means. comprising moving means for the holding means rotating the said retaining means, a part is connected to the biasing means, a first receiving portion for receiving an urging force of said urging means, one of said moving means A second receiving portion to which a portion is connected and which receives a force from the moving means, wherein the moving means includes a solenoid having a plunger movable in the axial direction, and a solenoid in a direction orthogonal to the axial direction. A release arm rotatably provided about an extended release shaft, the release arm being disposed at a position different from the connection part connected to the plunger and the connection part in the orthogonal direction. A pressing portion that presses the second receiving portion, the plunger is moved by energization of the solenoid to rotate about the release shaft, and the holding portion is rotated upward by the pressing portion. It is dynamic, the second receiving unit, before Symbol axial direction, is disposed in the vicinity of the first receiving portion, characterized in that.

According to the present invention, since the second receiving portion is arranged in the vicinity of the first receiving portion in the axial direction of the feeding rotating body, the deformation of the holding means is reduced, and the feeding rotating body is moved up and down with high positional accuracy. You can

1 is an overall schematic diagram showing a printer according to a first embodiment. FIG. 3 is a side view showing the manual feeding device in a state where the pickup roller is located at the contact position. FIG. 4 is a side view showing the manual feeding device in a state where the pickup roller is located at the separated position. The perspective view which shows a raising mechanism and a pickup arm. The perspective view which shows a manual feed tray and a side control member. The side view which shows a manual feeder. The figure which shows the manual feeder when a manual feed tray is closed. The side view which shows the manual feeder which concerns on 2nd Embodiment. The figure which shows the manual feeder when a manual feed tray is closed. The perspective view which shows the raising mechanism and pickup arm which concern on 3rd Embodiment.

<First Embodiment>
[overall structure]
First, the first embodiment of the present invention will be described. The printer 100 (image forming apparatus) according to the first embodiment is an electrophotographic laser beam printer that forms toner images of four colors. As shown in FIG. 1, the printer 100 includes a reader unit 43 that reads an image of a document, and a device body 90 that is provided below the reader unit 43. The apparatus main body 90 includes a cassette feeding unit 60, an image forming unit 1, a fixing device 5, and a manual feeding device 2 (sheet feeding device).

When the image forming command is output to the printer 100, the image forming process by the image forming unit 1 is started based on the image information input from the reader unit 43 or an external computer connected to the printer 100. The image forming unit 1 includes scanner units 13Y, 13M, 13C, and 13K, and four process cartridges 1Y that form four-color images of yellow (Y), magenta (M), cyan (C), and black (K). 1M, 1C, 1K. The four process cartridges 1Y, 1M, 1C, and 1K have the same configuration except that the colors of images to be formed are different. Only the image forming process of the process cartridge 1Y will be described, and the process cartridges 1M, 1C, and 1K will be described. The description is omitted.

The scanner unit 13Y emits laser light toward the photosensitive drum 11Y of the process cartridge 1Y based on the input image information. At this time, the photosensitive drum 11Y is charged in advance by the charger 12Y, and an electrostatic latent image is formed on the photosensitive drum 11Y by being irradiated with laser light. After that, the electrostatic latent image is developed by the developing device 14Y, and a yellow (Y) toner image is formed on the photosensitive drum 11Y.

Similarly, magenta (M), cyan (C), and black (K) toner images are also formed on the photosensitive drums of the process cartridges 1Y, 1M, and 1K. The toner images of the respective colors formed on the respective photosensitive drums are transferred to the intermediate transfer belt 36 by the primary transfer rollers 35Y, 35M, 35C and 35K, and are conveyed to the secondary transfer inner roller 37 by the rotating intermediate transfer belt 36. .. The image forming process for each color is performed at the timing of overlapping the upstream toner image primarily transferred onto the intermediate transfer belt 36.

In parallel with the above-described image forming process, the sheet S is fed from the cassette feeding unit 60 or the manual feeding device 2. The cassette feeding unit 60 has four stages of cassettes 61, 62, 63, 64, and feeding rollers 71, 72, 73, 74 corresponding to the respective cassettes. For example, according to the sheet size, An appropriate cassette is selected to feed the sheet.

The skew of the fed sheet S is corrected by the registration roller pair 75, and the sheet S is conveyed at a predetermined conveying timing. Then, the full-color toner image on the intermediate transfer belt 36 is transferred onto the sheet S by the inner secondary transfer roller 37 and the outer secondary transfer roller 41. The sheet S to which the toner image has been transferred is conveyed by the belt conveying body 42, and predetermined heat and pressure are applied in the fixing device 5 to melt and fix the toner. The sheet S that has passed through the fixing device 5 is discharged from the discharge port 50 to the outside of the machine.

When images are formed on both sides of the sheet, the sheet S on which the image is formed on the first side and which has passed through the fixing device 5 is conveyed to the reverse conveyance path 52 and is switchback-conveyed so that the front and back and front and back are reversed. .. Then, the sheet S is conveyed again to the registration roller pair 75 via the double-sided conveyance path 85, and the toner image is transferred to the second surface by the inner secondary transfer roller 37 and the outer secondary transfer roller 41.

[Manual feeder]
Next, the manual feeding device 2 will be described in detail. As shown in FIGS. 2 and 4, the manual feed device 2 includes a manual feed tray 30, a pickup roller 21, a feed roller 22, a retard roller 23, a lifting mechanism 3, a torsion coil spring 27, and a pull-out roller pair. 24 and. The manual feed tray 30 (stacking means) is supported by the apparatus main body 90 so as to be openable and closable, and stacks the sheets S.

The pickup roller 21 (feeding rotary member) feeds the sheets S stacked on the manual feed tray 30, and is held by a pickup arm 25 (holding means) so as to be able to move up and down. The feed roller 22 (conveying rotator) is rotatably supported by the feed roller shaft 29 (conveying rotator shaft) and conveys the sheet fed by the pickup roller 21.

The retard roller 23 (separation rotary member) is in pressure contact with the feed roller 22 and separates the sheets one by one together with the feed roller 22. Specifically, the retard roller 23 is supplied with a driving force in the direction opposite to the sheet conveying direction via the torque limiter 23a, and when one sheet is fed, the feed roller 22 is fed. Followed rotation. When two or more sheets are fed at the same time, the retard roller 23 rotates in the direction opposite to the sheet conveying direction.

The torsion coil spring 27 is wound around the feed roller shaft 29, one end of which is connected to a fixed frame (not shown), and the other end (a part) of which is the receiving portion 252 (first receiving portion) of the pickup arm 25. It is connected to the. The pickup arm 25 is urged downward by the urging force of the torsion coil spring 27, and the pickup roller 21 is in contact (press contact) with the sheets S stacked on the manual feed tray 30.

Since the pressure applied to the sheet S by the pickup roller 21 is related to the sheet feeding performance, it is desirable to reduce the variation. Therefore, the torsion coil spring 27 that applies an urging force to the pickup arm 25 is arranged at a position close to the pickup roller 21 so as to reduce disturbances to the urging force such as bending.

The sheet S conveyed by the feed roller 22 and the retard roller 23 is conveyed downstream by the pull-out roller pair 24 in the sheet conveying direction. A sensor 26 is provided between the feed roller 22 and the pull-out roller pair 24. When the sensor 26 detects a sheet, the pickup roller 21 is lifted by a lift mechanism 3 described later, as shown in FIG.

In this way, the pickup roller 21 rises and separates from the sheet S on the manual feed tray 30 after the sheet S has been fed, so that the pickup roller 21 does not feed the sheet S too much, and the sheet by the retard roller 23 is prevented. The separation effect can be improved. The lifted pickup roller 21 descends at the timing of the next sheet feeding, and comes into contact with the sheet S on the manual feed tray 30 again.

[Rise mechanism]
As shown in FIG. 4, the lifting mechanism 3 includes a solenoid 28 that is an actuator and a release arm 282 that is a link mechanism, and is disposed above the pickup roller 21. The solenoid 28 has a plunger 28a that linearly moves in a direction parallel to the axial direction of the feed roller shaft 29, and the plunger 28a is fixed to the flange portion 282b of the release arm 282.

A pressing portion 282a projects radially below the release arm 282, and the pressing portion 282a abuts a release rib 251 (second receiving portion) formed integrally with the pickup arm 25. The release arm 282 rotates around the release shaft 281 when the solenoid 28 is energized and the plunger 28a retracts, and the release rib 251 also rotates together with the release arm 282. Accordingly, the release arm 282 rotates the pickup arm 25 upward against the biasing force of the torsion coil spring 27, and the pickup roller 21 swingably held by the pickup arm 25 is separated from the sheet S at the separated position. Rise to. That is, the release arm 282 transmits the movement of the solenoid 28 to the release rib 251.

On the contrary, when the energization of the solenoid 28 is stopped, the plunger 28a projects, the release rib 251 returns to its original position by the torsion coil spring 27, and the pickup roller 21 descends to the contact position where it contacts the sheet S.

[Position of action point and release point]
Here, the positional relationship between the action point A of the receiving portion 252 where the pickup arm 25 receives the biasing force from the other end of the torsion coil spring 27 and the release point B where the release rib 251 receives the force from the lifting mechanism 3 will be described.

In the present embodiment, as shown in FIGS. 4 and 7, the release point B is arranged near the action point A in the axial direction (thrust direction) of the feed roller shaft 29. By making the action point A and the release point B close to each other in the axial direction in this way, the bending of the pickup arm 25 caused by the force of the lifting mechanism 3 pulling the release rib 251 and the force of the torsion coil spring 27 urging the pickup arm 25. Can be reduced.

Therefore, the pickup roller 21 can be accurately positioned at the separated position. Even if the feed roller shaft 29 is formed of a relatively soft resin, for example, the pickup arm 25 and the feed roller shaft 29 do not bend so much and it is not necessary to design the feed roller shaft 29 in consideration of the amount of the bending. As a result, it is possible to prevent an increase in the collision noise of the pickup roller 21 and an increase in the up/down time of the pickup roller, while being lightweight and low cost.

Further, in the present embodiment, the release rib 251 is arranged in the vicinity of the receiving portion 252 of the pickup arm 25 so that the release point B is arranged close to the point of action A in the axial direction. Note that the vicinity in this embodiment refers to being arranged closer than 50 mm, and preferably being arranged closer than 30 mm. The release rib 251 is arranged between the receiving portion 252 and the pickup roller 21. Note that the release rib 251 and the receiving portion 252 may be arranged such that some or all of the release rib 251 and the receiving portion 252 overlap each other in the axial direction.

[Arrangement of side regulating member and lifting mechanism]
By the way, on the manual feed tray 30, as shown in FIG. 5, a pair of side regulating members 31a and 31b (regulating members) that regulate the positions of both ends of the stacked sheets in the width direction orthogonal to the sheet feeding direction. Is provided. The side restricting members 31a and 31b are configured to be movable in a predetermined range in the width direction around the center line C of the sheet, and move in the opposite direction in conjunction with each other. The opening width of the pair of side regulating members 31a and 31b is set to the maximum width and the minimum width of the sheet that can be fed, and is set to 100 mm to 330 mm in the present embodiment.

As shown in FIG. 6, the manual feed tray 30 is rotatably supported by the apparatus main body 90 about a rotation shaft 30a, and is held by a tray stopper 32 in a vertical state (position shown by a solid line in FIG. 6). It At this time, since the side regulating members 31a and 31b are also accommodated in the apparatus main body 90 together with the manual feed tray 30, the accommodating space is required for the movement trajectory of the side regulating members 31a and 31b.

That is, as shown in FIG. 7, the storage space P of the side regulating members 31a, 31b is moved so that the side regulating members 31a, 31b can be accommodated regardless of the opening width of the side regulating members 31a, 31b. A space needs to be provided in the width of the feasible areas D and E.

The pickup roller 21, the pickup arm 25, the torsion coil spring 27, the lifting mechanism 3 and the like according to the present embodiment are arranged in a region T that is inside the minimum opening width Xmin of the side regulating members 31a and 31b when the tray is stored. Therefore, the manual feeding device 2 and the printer 100 can be configured compactly.

Further, since the solenoid 28 is arranged so that the plunger 28a of the solenoid 28 moves parallel to the axial direction of the feed roller shaft 29, the manual feeding device 2 can be made compact.

Note that the pickup roller 21, the feed roller 22, and the retard roller 23 are not limited to rollers, but may be constituted by a rotating body such as a belt. Further, instead of the solenoid 28, another actuator such as a hydraulic actuator or a servo motor may be applied.

Further, the present invention can be applied not only to the manual feeding device 2 but also to the cassette feeding unit 60.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. The second embodiment is configured by applying a compression spring instead of the torsion coil spring of the first embodiment. Therefore, the configuration similar to that of the first embodiment will be described by omitting the illustration or by attaching the same reference numeral to the figure.

[Manual feeder]
As shown in FIG. 8, the manual sheet feeding device 2A (sheet feeding device) has a pickup arm 25A that holds the pickup roller 21 so that the pickup roller 21 can move up and down. The pickup arm 25A has a receiving portion that projects upward. 25a (first receiving portion) is formed. A compression spring 33 (biasing means) is contracted between a feeding frame (not shown) and the receiving portion 25a, and the compression spring 33 is located at a contact position where the pickup roller 21 contacts the sheet. It is biased to position.

Then, in the pickup arm 25A, as in the first embodiment, when the solenoid 28 is energized, the release rib 251 rotates, and the pickup arm 25A rotates upward about the feed roller shaft 29. When the pickup arm 25A rotates upward, the pickup roller 21 is located at a separated position where it is separated from the sheet S.

[Position of action point and release point]
Here, the positional relationship between the action point A of the receiving portion 25a where the pickup arm 25A receives the biasing force from the compression spring 33 and the release point B where the release rib 251 receives the force from the lifting mechanism 3 will be described.

Also in this embodiment, as shown in FIG. 9, the release point B is arranged near the action point A in the axial direction (thrust direction) of the feed roller shaft 29. By thus bringing the action point A and the release point B closer to each other in the axial direction, the lifting mechanism 3 pulls the release rib 251 and the compression spring 33 urges the pickup arm 25A. Deflection can be reduced. Therefore, the pickup roller 21 can be accurately positioned at the separated position.

Further, in the present embodiment, the release rib 251 is arranged in the vicinity of the receiving portion 25a of the pickup arm 25A so that the release point B is arranged close to the action point A in the axial direction. Note that the vicinity in this embodiment refers to being arranged closer than 50 mm, and preferably being arranged closer than 30 mm. The release rib 251 is arranged between the receiving portion 25a and the pickup roller 21. Note that the release rib 251 and the receiving portion 25a may be arranged such that a part or all of the release rib 251 and the receiving portion 25a overlap each other in the axial direction.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. In the third embodiment, the raising mechanism of the first embodiment is configured in another configuration. Therefore, the configuration similar to that of the first embodiment will be described by omitting the illustration or by attaching the same reference numeral to the figure.

As shown in FIG. 10, the raising mechanism 3B (moving means) is composed of a solenoid 128 which is an actuator, and is arranged above the pickup roller 21. The solenoid 128 has a plunger 128a that linearly moves in a direction along the sheet feeding direction, and the plunger 128a is directly fixed to the release rib 251 of the pickup arm 25. The direction along the sheet feeding direction includes not only the sheet feeding direction but also a direction deviated from the sheet feeding direction by about ±20 degrees.

When the solenoid 128 is energized, the plunger 128a retracts, the release rib 251 rotates, and the pickup arm 25 rotates upward about the feed roller shaft 29. When the pickup arm 25 rotates upward, the pickup roller 21 is positioned at the separated position where the pickup roller 21 is separated from the sheet S.

On the contrary, when the energization of the solenoid 128 is stopped, the plunger 128a projects, the release rib 251 returns to the original position by the torsion coil spring 27, and the pickup roller 21 descends to the contact position where it contacts the sheet S.

1: image forming unit/2, 2A: sheet feeding device (manual feeding device)/3, 3B: moving means (raising mechanism)/21: feeding rotating member (pickup roller)/22: conveying rotating member (feed) Roller)/23: Separation rotator (retard roller)/25, 25A: Holding means (pickup arm)/25a, 252: First receiving portion (receiving portion)/27, 33: Energizing means (torsion coil spring, compression spring) )/28, 128: Actuator, solenoid/28a, 128a: Plunger/29: Transport rotary body shaft (feed roller shaft)/30: Stacking means (manual feed tray)/31a, 31b: A pair of regulation members (a pair of side regulation) Member)/100: image forming apparatus (printer)/251: second receiving portion (release rib)/282: link mechanism (release arm)

Claims (7)

Stacking means for stacking sheets,
A feeding rotating body capable of feeding the sheets stacked on the stacking unit,
A conveyance rotator that conveys the sheet fed by the feed rotator,
A carrier rotating body shaft that rotatably supports the carrier rotating body,
A separation rotator that is brought into pressure contact with the conveyance rotator and separates the sheets together with the conveyance rotator one by one;
Holding means for holding the feeding rotating body so as to be able to move up and down, and rotating around the transport rotating body axis ;
Urging means for urging the holding means so that the feeding rotating body is brought into contact with the sheets stacked on the stacking means,
Above the feeding rotary member, and is disposed at a position overlapping with the retaining means in the axial direction of the conveying rotary member axis, against the biasing force of the biasing means, and moving means for rotating said holding means ,,
The holding means is connected to a part of the biasing means and receives a biasing force of the biasing means, and a part of the moving means is connected to receive a force from the moving means. A second receiving portion,
The moving means has a solenoid having a plunger movable in the axial direction, and a release arm rotatably provided around a release shaft extending in an orthogonal direction orthogonal to the axial direction,
The release arm has a connecting portion connected to the plunger and a pressing portion arranged at a position different from the connecting portion in the orthogonal direction and pressing the second receiving portion, and energizing the solenoid. The plunger moves to rotate about the release shaft, and the pressing unit rotates the holding unit upward,
Said second receiving unit, before Symbol axial direction, is disposed in the vicinity of the first receiving portion,
A sheet feeding device characterized by the above. A distance in the axial direction between the first receiving portion and the second receiving portion is within 50 mm,
The sheet feeding device according to claim 1, wherein: The second receiving portion is arranged so as to at least partially overlap the first receiving portion in the axial direction.
The sheet feeding device according to claim 1 or 2, wherein. The sheets stacked on the stacking unit are provided with a pair of regulating members that regulate the positions of both end portions in the width direction orthogonal to the sheet feeding direction, and are movable in the width direction within a predetermined range,
The moving means is arranged between the pair of regulating members when the opening width of the pair of regulating members in the predetermined range is minimum.
The sheet feeding device according to any one of claims 1 to 3, wherein The feeding rotating body, the holding means and the urging means are arranged between the pair of regulating members when the opening width of the pair of regulating members in the predetermined range is minimum.
The sheet feeding device according to claim 4, wherein: The urging means is a torsion coil spring wound around the transport rotary body shaft,
The sheet feeding device according to claim 1 , wherein the sheet feeding device is a sheet feeding device. A sheet feeding device according to any one of claims 1 to 6 ,
An image forming unit that forms an image on the sheet fed by the sheet feeding device,
An image forming apparatus characterized by the above.

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