JPH08310668A - Sheet feeding device and image forming device provided with sheet feeding device - Google Patents

Abstract

PURPOSE: To miniature devices, and to reduce the cost of the devices by detaching a claw from a sheet stopper when the feeding means is moved from the waiting position to the feeding position and by engaging the sheet stopper with the claw when a feeding means is in the waiting position. CONSTITUTION: When a sheet feeding action is started, a pickup roller 4 is lowered from a waiting position to a feeding position by the effect of a control solenoid 8. Engagement of a hook part 7b of a claw 7 with an upper tip 6c of a sheet stopper 6 is released. When a sheet is fed, the pickup roller 4 is abutted on the highest sheet S1 on a sheet tray 1, and the sheet S1 is fed to a feed roller 2 side, and the sheet stopper 6 is pushed by the sheet S1 and turned in the E direction. The control solenoid 8 is operated, and the pickup roller 4 is lifted, and then, the rear end of the sheet S1 passes between a lower tip 6b and the sheet tray 1, the sheet stopper 6 is turned by the self weight to arrange the tip position of the sheet S. At the same time, the upper tip 6c is engaged with the claw 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus used in an image forming apparatus such as a copying machine, a printer, a facsimile, and an image forming apparatus equipped with the sheet feeding apparatus.

[0002]

2. Description of the Related Art Conventionally, a sheet feeding apparatus used in this type of image forming apparatus has an image forming means using a pickup roller in which one of a plurality of sheets stacked on a sheet tray is arranged above the sheet tray. It is designed to be sent to the side. After the sheet is sent out from the sheet tray, the leading edge position of the sheet on the sheet tray is aligned by the sheet aligning means in preparation for the next sheet supply.

[0003]

However, in the conventional sheet feeding apparatus, since the sheet aligning means is directly driven and controlled by the solenoid or the motor, it is possible to sufficiently meet the demand for downsizing of the apparatus. I can't
It was also difficult to reduce the cost of the device.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to simplify the structure of the sheet aligning means and to reduce the size and cost of the sheet feeding device, and thus to reduce the size and cost of the image forming apparatus.

[0005]

The sheet feeding device of the present invention has been devised to solve the above-mentioned problems.
A sheet stacking unit that is arranged on the apparatus main body side and stacks a plurality of sheets, and is arranged so as to be able to contact and separate from the sheets on the sheet stacking unit, and is moved to a sheet from a retracted position separated from the sheet during sheet feeding. And a sheet aligning unit that aligns the sheets on the sheet stacking unit when the sheet feeding unit is located at the retracted position. A sheet feeding device, wherein the sheet aligning means is attached to the feeding means and is provided rotatably in the sheet feeding direction; and the sheet stopper when the feeding means reaches a retracted position. A claw that holds the sheet stopper in the sheet alignment position by engaging with the sheet stopper and that is disengaged from the sheet stopper when the feeding unit moves from the retracted position to the feeding position,
It is characterized by having.

An image forming apparatus of the present invention is characterized by including the above-described sheet feeding device and an image forming means for forming an image on a sheet fed from the sheet feeding device. .

[0007]

When the feeding means is in the retracted position, the sheet stopper is engaged with the pawl and the posture of the sheet stopper is maintained. When the feeding unit moves from the retracted position to the feeding position, the engagement between the sheet stopper and the pawl is released, and the sheet stopper can be rotated. When the feeding unit moves to the feeding position and feeds the sheet, the sheet stopper is rotated by the sheet fed by the feeding unit to allow the movement of the sheet. When the sheet feeding by the feeding unit is completed and the feeding unit moves from the feeding position to the retracted position, the sheet stopper rotates by its own weight in the direction opposite to the sheet feeding direction to move the sheets on the sheet stacking unit. Align. When the feeding means reaches the retracted position, the sheet stopper engages with the claw, and the claw holds the sheet stopper in a predetermined posture.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. (Embodiment 1) FIG. 1 shows a sheet feeding apparatus 50 showing a first embodiment of the present invention.

In FIG. 1, a plurality of sheets S are stacked on a sheet tray 1 as sheet stacking means. At the left end of the sheet tray 1 in the figure, a feed roller 2 for feeding the sheet S on the sheet tray 1 in a predetermined direction on the left side of the figure, and a retard roller 3 for retard-separating the sheet S are arranged. ing.

The left end of the pickup plate 5 in the figure is attached to the shaft 2a of the feed roller 2 so as to be freely rotatable. Then, at the right end portion of the pickup plate 5 in the drawing, a pickup roller 4 as a feeding means for feeding the sheet S on the sheet tray 1 to the feed roller 2 side.
Is rotatably attached via a shaft 6a, and a sheet stopper 6 for adjusting the position of the left end portion (front end portion in the sheet conveyance direction) in the drawing of the sheet on the sheet tray (aligning the sheets) is provided via the shaft 6a. It is rotatably attached.

Of these, the sheet stopper 6 is formed in such a shape that it can be rotated by its own weight in the counterclockwise direction in the drawing (the direction opposite to the sheet feeding direction) about the shaft 6a as the center of rotation, and its lower end 6b. Comes into contact with a positioning portion (not shown) formed on the sheet tray 1 and stops at the position A. The sheet stopper 6 has an upper tip 6
c is engaged with the claw 7. Therefore, the seat stopper 6 is prevented from rotating in the B direction by a positioning portion (not shown), and is prevented from rotating in the E direction by the hook portion 7b of the claw 7.

The claw 7 is attached to the apparatus main body 101 (see FIG. 8) via a shaft 7a so that it can rotate in the direction C in the figure by its own weight, and is stopped at a position D in the figure. It has become. The hook 7b is formed at the tip of the claw 7. And this hook part 7
In b, the engaging surface 6c of the upper tip 6c of the sheet stopper 6 is shown.
The first inclined surface 7b ₁ engaging with ₁ and the second inclined surface 7b contacting with the contact surface 6c ₂ of the upper end 6c of the sheet stopper 6
₂ is formed. The angle θ between the engagement surface 6c ₁ and the first inclined surface 7b ₁ is that of the claw 7 when the pickup roller 4 moves from the retracted position to the feeding position, as shown in FIG. The angle is set such that the engagement state between the hook portion 7b and the upper end 6c of the sheet stopper 6 is smoothly released (disengaged). The sheet stopper 6 and the claw 7 constitute sheet aligning means for aligning the sheets S.

A control solenoid 8 for rotating the pickup plate 5 is connected to a substantially central portion of the pickup plate 5. When the control solenoid 8 operates, the pickup plate 5 rotates about the shaft 2a, and the pickup roller 4 moves between the retracted position shown in FIG. 1 and the feeding position shown in FIG. 2 (FIGS. 1 to 1). 6).

The sheet stopper 6, the pickup roller 4, and the pickup plate 5 are connected to the shaft 6a while being displaced in the thrust direction (direction perpendicular to the paper surface of FIG. 1).
They are arranged so that they do not interfere with each other.

Next, the operation of the sheet feeding device 50 will be described.

When the sheet is withdrawn, the pickup plate 5 and the pickup roller 4 are stopped at the positions shown in FIG. 1, and the lower end 6a of the sheet stopper 6 is stopped at the position A. The sheet S is stacked on the sheet tray with its left end in the drawing abutting against the sheet stopper 6.

At the start of the paper feeding operation, the pickup roller 4 is lowered from the retracted position toward the feeding position by the action of the control solenoid 8. At this time, the hook portion 7b of the claw 7 and the upper end 6c of the sheet stopper 6 are disengaged. still,
The engagement between the hook portion 7b of the claw 7 and the upper end 6c of the sheet stopper 6 is smoothly released by slightly elastically deforming the claw 7 and the sheet stopper 6.

At the time of sheet feeding, the pickup roller 4 has moved to a position (feeding position) where it comes into contact with the uppermost sheet S1 on the sheet tray 1, and is rotated by a driving means (not shown) to rotate the uppermost sheet. S1 is sent to the feed roller 2 side. It should be noted that the notch or slit engaging with the sheet stopper 6 is provided on the sheet tray 1 so that the lower front end 6b of the sheet stopper 6 can be lowered below the sheet tray 1 at the time of sheet feeding (see FIG. 3). (Not shown) is formed. Then, the sheet stopper 6 is pushed by the sheet S1 sent out by the pickup roller 4, and rotates in the E direction as shown in FIG.

The sheet S1 passes through the space F between the lower end 6b of the sheet stopper 6 and the sheet tray 1 and is fed to the feed roller 2 side (see FIG. 3). After the leading edge of the sheet S1 is nipped by the feed roller 2 and the retard roller 3, the control solenoid 8 is actuated and the pickup roller 4 is moved to the position shown in FIG.
Can be lifted to the position shown in.

Thereafter, the lower end 6b of the sheet stopper 6 is
And when the F between the sheet tray 1 Sea Bok rear end of S1 is passing through, the sheet stopper 6 is rotated by its own weight in the B direction as shown in FIG. 5, the hook portion of the contact surface 6c ₂ nails 7 7b
Abutting on the second inclined surface 7b ₂ . At this time, the moment Gm due to the force G applied to the claw 7 from the sheet stopper 6
Is set to be larger than the moment H at which the claw 7 tries to rotate in the C direction (see FIG. 5). Therefore, the sheet stopper 6 pushes the claw 7 upward and engages the engaging surface 6c ₁ thereof with the first inclined surface 7b ₁ of the claw 7.
As a result, the sheet feeding device returns to the first retracted position as shown in FIG.

As described above, in this embodiment, the sheet stopper 6 rotates by its own weight to align the leading end positions of the sheets S on the sheet tray 1, and the sheet stopper 6 returns from the feeding position to the retracted position. At this time, since it is configured to be engaged with the claw 7 by the turning force by its own weight, a driving means such as a special motor for controlling the rotation of the sheet stopper 6 unlike the conventional example is not required, and the structure is simplified, Miniaturization of equipment
The cost can be reduced. (Second Embodiment) The same components as those of the first embodiment are designated by the same reference numerals as those of the first embodiment, and the detailed description will be omitted without duplicating description.

FIG. 7 shows a sheet feeding apparatus according to the second embodiment of the present invention.

The structural difference between this embodiment and the first embodiment is the shape of the engaging portion between the claw 7 and the sheet stopper 6. That is, regarding the angle θ between the engaging surface 6c ₁ of the sheet stopper 6 and the engaging portion of the first inclined surface 7b ₁ of the claw 7, the angle θ in the above embodiment is inclined to the left in the figure with respect to the center line of the shaft 6a. On the other hand, it is formed so as to be inclined to the right side in the drawing with respect to the center line.

In this embodiment, when the pickup roller 4 moves from the feeding position to the retracted position, the contact surface 6c ₂ of the sheet stopper 6 first contacts the second inclined surface 2a of the claw 7 to cause the sheet stopper. The turning force by the own weight of 6 causes the pawl 2 to rotate about the shaft 7a, and thereafter, the upper end 6c of the sheet stopper 6 engages with the hook portion 7b of the pawl 7 as shown in FIG.

On the other hand, when the pickup roller 4 moves from the retracted position toward the feeding position, there is nothing on the claw 7 side that hinders the movement of the sheet stopper 6, so that the sheet stopper 6 is larger than that in the first embodiment. Move smoothly. And
The sheet stopper 6 rotates counterclockwise in the drawing to the position A in FIG. 7 and stops, and the sheet S on the sheet tray 1 is stopped.
Align. In this embodiment, the normal direction Tl of the contact portion between the sheet stopper 6 and the claw 7 is the rotation center 7a of the claw 7.
Since it is configured to pass above and below the rotation center 2a of the pickup plate 5, the pickup plate 5 rotates smoothly.

The sheet feeding apparatus 50 of the present embodiment operates in the same manner as in the first embodiment, and as in the first embodiment, the size and cost of the apparatus can be reduced.

The angle θ in each of the above-described embodiments is appropriately set to a preferable angle so that the seat stopper 6 and the claw 7 can be smoothly engaged and disengaged. (Image Forming Apparatus) FIG. 8 is a schematic configuration diagram of an image forming apparatus including the sheet feeding apparatus 50 as shown in each of the above-described embodiments.

This image forming apparatus comprises a cassette 103 in which a predetermined amount of sheets S are stacked and stored in the lower part of the apparatus main body 101,
In addition to the sheet feeding device 105, the sheet feeding device 50 as a manual sheet feeding unit is provided.

The sheet feeding apparatus 50 as a sheet feeding unit for feeding the sheet S is provided with a retard separation type sheet feeding apparatus 106 (the feed roller 2 and the retard roller 3 of the first and second embodiments). ing. Further, retard universal sheet feeding devices 107 and 109 are provided at the installation sites of the universal cassettes 103 and 105, respectively.

Sheet feeding device 50, cassettes 103, 1
The sheet S in 05 is the sheet feeding device 106, 10
When the paper is fed by 7, 109, it is first sent to the pair of registration rollers 110 that are not rotating, and the skewed state is corrected there.

Next, the sheet S is fed to the photosensitive drum 111 side by the pair of rotating registration rollers 110 at a timing with the latent image formed on the photosensitive drum 111 as an image forming means, and is transferred onto the photosensitive drum 111. Toner image is transferred (image is formed).

After that, the sheet S is sent to the fixing device (fixing roller pair) 115 by the conveyor belt 113, and a fixing process for fixing the toner image transferred here to the sheet surface is performed.

The image forming apparatus has a double-sided copy mode for performing double-sided copy on the sheet S and a multiplex copy mode for performing multiplex copy. In the normal copying mode, the sheet S after the fixing process is discharged to the discharge tray 119 outside the apparatus by the inner discharge roller pair 116 and the outer discharge roller pair 117. Also, in the double-sided copy mode and multiple copy mode,
The sheet S is temporarily stacked and stored on the intermediate tray 121 by the inner paper discharge roller pair 116 or the switchback roller pair 127 via the repaper feed path 120 and the double-sided transport path 126. Then, the sheet stored on the intermediate tray 121 is again conveyed to the registration roller pair 110 for image formation by the sheet re-feeding device 130, and thereafter discharged through the same process as single-sided copying.

Since the image forming apparatus of the present embodiment having the above-described structure is equipped with the sheet feeding device 50 shown in the first or second embodiment, the overall size and cost of the image forming apparatus can be reduced. Can be achieved.

[0035]

As described above, in the sheet feeding apparatus of the present invention, the sheet aligning means for aligning the sheets on the sheet stacking means is attached to the feeding means and is self-weighted in the direction opposite to the sheet feeding direction. It consists of a sheet stopper that rotates a predetermined angle and a claw that engages with and disengages from the sheet stopper. The sheet stopper rotates by its own weight to align the leading end positions of the sheets on the sheet stacking means, and the sheet stopper feeds the sheet. The driving means, such as a motor, which directly controls the rotation of the sheet stopper as in the conventional example, is configured to engage with the pawl by the turning force by its own weight when returning from the feeding position to the retracted position together with the means. Is unnecessary, the structure is simplified, and the size and cost of the device can be reduced.

Further, since the image forming apparatus of the present invention is provided with the sheet feeding apparatus which is simple in structure as described above and which can be made compact and inexpensive, the image forming apparatus as a whole can be made compact and inexpensive. be able to.

[Brief description of drawings]

FIG. 1 is a sectional view of a sheet feeding device showing a first embodiment of the present invention.

FIG. 2 is a first operational state diagram of the same device.

FIG. 3 is a second operational state diagram of the device.

FIG. 4 is a third operational state diagram of the same device.

FIG. 5 is a fourth operation state diagram of the same device.

FIG. 6 is a fifth operating state diagram of the same apparatus.

FIG. 7 is a cross-sectional view of a sheet feeding device showing a second embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of an image forming apparatus including the sheet feeding apparatus of the present invention.

[Explanation of symbols]

 1 Sheet Tray (Sheet Stacking Means) 4 Pickup Roller (Feeding Means) 6 Sheet Stopper (Sheet Aligning Means) 7 Claw (Sheet Aligning Means) 50 Sheet Feeding Device 101 Device Main Body 111 Photosensitive Drum (Image Forming Means) S Sheet

Claims (2)

[Claims] 1. A sheet stacking unit that is arranged on the apparatus main body side and stacks a plurality of sheets, and is arranged so as to be able to come into contact with and separate from the sheets on the sheet stacking unit, and is separated from the sheets at the time of sheet feeding. Sheet feeding means for moving the sheet from the retracted position to the sheet feeding position where it abuts the sheet and feeding the sheet, and a sheet aligning means for aligning the sheets on the sheet stacking means when the sheet feeding means is located in the retracted position. And a sheet stopper attached to the sheet feeding means and rotatably provided in a sheet feeding direction, and the sheet feeding means reaches a retracted position. A pawl that engages with the sheet stopper and holds the sheet stopper at the sheet aligning position, and separates from the sheet stopper when the feeding unit moves from the retracted position to the feeding position; A sheet feeding device comprising: 2. The sheet feeding device according to claim 1,
An image forming apparatus comprising: an image forming unit that forms an image on a sheet fed from the sheet feeding apparatus.