JPH05162869A - Paper sheet feeder - Google Patents

Abstract

PURPOSE:To reduce the number of parts, simplify the structure and reduce the manufacturing cost by embodying a mechanism for positioning the paper- feeding rollers in their stopping position with a simple mechanism. CONSTITUTION:In the rotation stop condition of paper-feeding rollers 6, a lockedly engaging lever 12 is engaged with the engaging groove 11 of a cam 10, and the paper-feeding rollers 6 are positioned and retained in such a condition that the flat parts 6b thereof have been turned downward. At the time when the rotation of the paper-feeding rollers 6 is to start, a pulse motor 7 is started in a low-speed region where torque is large, and the cam 10 is turned against the lockedly engaging/retaining force by means of the lockedly engaging lever 12 for releasing the engagement. When the cam 10 is returned to the engaging condition after the completion of paper-feeding action by means of the paper-feeding rollers 6, the speed of the pulse motor 7 is reduced, and then is stopped. Thus, the cam 10 is not turned beyond the engaging position to be engaged with the lockedly engaging lever 12, and the lever 12 is securely engaged with the engaging groove 11, so that the respective paper-feeding rollers 6 are securely stopped and retained in such a condition that the flat parts 6b thereof have been turned downward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for feeding sheets such as recording sheets one by one in a facsimile machine, a printer or the like.

[0002]

2. Description of the Related Art In this type of sheet feeding apparatus, a sheet feeding roller having a substantially half-moon shape in cross section is disposed above one side of a sheet feeding cassette that accommodates a large number of sheets in a stacked state. The paper feed roller is arranged so that the flat part faces downward so that the paper feed cassette can be easily attached and detached when the rotation is stopped.
When the sheet is fed, the sheet is rotated once from this state, and the arc portion of the sheet feeding roller feeds the sheet one by one from the sheet feeding cassette.

[0003]

However, in the above-described conventional paper feeding apparatus, the rotation position of the paper feeding roller is detected in order to stop the half-moon shaped paper feeding roller at the position where the flat portion faces downward. Therefore, it is necessary to provide a sensor for controlling the position, and a solenoid for positioning the paper feed roller at the stop position based on the detection of the rotational position by the sensor.
Therefore, there are problems that the number of parts increases, the structure becomes complicated, and the production cost increases.

The present invention has been made to solve the above problems, and an object thereof is to make it possible to realize a mechanism for positioning the stop position of the sheet feeding roller with a simple mechanism and reduce the number of parts. The purpose of the present invention is to provide a sheet feeding device that can reduce the production cost by simplifying the structure.

[0005]

In order to achieve the above object, according to the present invention, a half-moon-shaped sheet feeding roller for feeding sheets in a sheet feeding cassette one by one, a motor for rotating the sheet feeding roller, and a sheet feeding roller. A holding member that holds the paper roller in a state where its flat portion is on the paper side, and the paper feed roller is started to rotate at a low speed from the held state, and after the holding is released, the paper feed speed is shifted to and then the paper feed speed is decelerated. A control means for controlling the rotation of the motor so as to be stopped in the holding state is provided.

[0006]

Therefore, according to the present invention, when the paper feed roller is in the rotation stopped state, the paper feed roller is positioned and held by the holding member with the flat portion facing the paper. Then, when the rotation of the paper feed roller is started, the motor is started to rotate at a low speed, so that the motor generates a large torque, the paper feed roller is rotated against the holding force of the holding member, and the holding is released. It After that, the paper feed roller is moved to the paper feed speed.
When the paper feed roller returns to the holding state, the motor is decelerated and then stopped. Therefore, since the paper feed roller is at a low speed immediately before returning to the holding state, the paper feed roller is securely held by the holding member without rotating beyond the holding position by the holding member, and the flat portion thereof faces downward. It is stopped and held reliably in the state.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a paper feed cassette 1 which is detachably mounted in a device frame (not shown) of a facsimile machine or the like is formed in a substantially box shape with an open upper surface, and has a large number of recordings therein. The sheets Y are accommodated in a stacked state. The push-up plate 2 is tiltably arranged on the inner bottom portion of the paper feed cassette 1, and a spring 3 is interposed between the push-up plate 2 and the inner bottom portion of the paper feed cassette 1. Then, the spring 3 urges the push-up plate 2 to tilt upward, and the tilting pushes up the portion of the paper Y on the delivery side. The pair of separation claws 4 are arranged on both sides of the paper feed side of the paper feed cassette 1, and the paper Y is separated and fed from the paper feed cassette 1 one by one by the separation pawls 4.

The rotary shaft 5 is rotatably supported in the apparatus frame so as to extend in a direction orthogonal to the paper transport direction at a position above the paper feed side of the paper feed cassette 1, and a pair of rotary shafts 5 are provided on the rotary shaft 5. A half-moon-shaped sheet feeding roller 6 is supported so as to be integrally rotatable. The pulse motor 7 has a rotating shaft 5
Of the rotary shaft 5 and the paper feed roller 6 via a drive gear 8 mounted on the output shaft of the apparatus frame near one end of the drive gear and a driven gear 9 meshing with the drive gear 8.
Is rotated clockwise in the figure. Then, as the paper feed roller 6 rotates, the circular arc portion 6a of the roller 6 causes the uppermost sheet Y
In contact with the sheet Y, the sheet Y is sent out from the sheet feeding cassette 1 one by one. The pulse motor 7 has a built-in rotation amount detector 18 (shown in FIG. 3) such as an encoder so that the paper feed roller 6 is rotated once for the feeding operation of one sheet of paper Y.

The cam 10 is integrally rotatably supported by the rotating shaft 5 at a position separated from the upper position of the paper feeding cassette 1, and one engaging groove 11 is formed on the peripheral surface thereof. The engagement groove 11 is composed of a V-shaped main engagement portion 11a and auxiliary engagement portions 11b on both sides of the main engagement portion 11a which are smoothly continuous with the outer peripheral surface of the cam 10. The locking lever 12 is provided in the frame of the device so as to face the peripheral surface of the cam 10.
It is rotatably supported by. Then, the locking lever 12 is urged to rotate clockwise in the drawing by the spring 14,
The locking claw 12a at its tip is constantly pressed against the peripheral surface of the cam 10. When the flat portion 6b of the sheet feeding roller 6 faces downward and faces the sheet Y, the locking lever 1
The second engaging claw 12a is the main engaging portion 1 of the engaging groove 11 of the cam 10.
The rotational position of the cam 10 is retained by engaging the cam 1a. Cam 10, locking lever 12, and spring 1
4, the holding member is formed.

Next, the circuit configuration of the components related to the sheet feeding operation of the sheet feeding device will be described. As shown in FIG. 3, a CPU (Central Processing Unit) 15 is connected to a ROM (Read Only Memory) 16 that stores a program for controlling the operation of the entire device. Also, CPU1
5, a rotation amount detection signal from the rotation amount detector 18,
And an operation command signal from the outside is input. Also, CPU
Reference numeral 15 outputs a drive pulse signal to the pulse motor 7 via the driver 17.

The ROM 16 stores the operation pattern data of the pulse motor 7 corresponding to one rotation of the paper feed roller 6 and the cam 10. Further, in this embodiment, the CPU 15, the ROM 16, and the rotation amount detector 18 constitute a control means. That is, the CPU 15
Based on the operation pattern data stored in the ROM 16 and the output signal from the rotation amount detector 18, the driver 17 is controlled to rotate the pulse motor 7.

That is, when the operation command signal is not input from the outside, the CPU 15 does not output the drive pulse signal and stops the pulse motor 7. Then, in this state, as shown in FIG. 4A, the locking claw 12a of the locking lever 12 is engaged with the engaging groove 11 of the cam 10, that is, the sheet feeding roller 6 has the flat portion 6b. Is held in a downward position.

When an operation command signal is input from the outside, the CPU 15 controls the driver 17 based on the output signal from the rotation amount detector 18, activates the pulse motor 7 at a low speed, and gradually accelerates. In addition, when the pulse motor 7 reaches a predetermined rotation speed, the motor 7 is rotated at the predetermined rotation speed at a constant speed for a certain time. Then the CPU
Reference numeral 15 controls the driver 17 to gradually reduce the speed of the pulse motor 7, and in response to the paper feed roller 6 and the cam 10 making one rotation to return to the state of FIG. Stop.

That is, as shown in FIG. 5, the paper feed roller 6 and the cam 10 start to rotate at a low speed by starting the pulse motor 7 from the state shown in FIG. Be accelerated. Then, in the low speed state, the cam 10 is released from the locked state by the locking lever 12.
Then, as shown in FIG. 4B, when the arc portion 6a of the paper feed roller 6 approaches the position where it comes in contact with the paper Y, the pulse motor 7 reaches a predetermined rotation speed and the paper feed roller 6 is fed. Speed required for paper operation (paper feed speed)
Reach Then, the circular arc portion 6a of the paper feed roller 6 causes the paper Y
While in contact with the upper side, the pulse motor 7 is rotated at a constant speed at the predetermined rotation speed, and the paper feed roller 6 is rotated while being kept at the paper feed speed. Then, as shown in FIG. 4C, when the paper feed roller 6 is rotated to a position where the contact of the arcuate portion 6a with the paper Y ends, the paper feed roller 6 is gradually decelerated by the pulse motor 7. Then, it is stopped at the position shown in FIG.

Next, the operation of the sheet feeding device configured as described above will be described. Now, in the operation stop state of the apparatus and the standby state of the sheet feeding operation, as shown in FIGS. 1 and 4A, the locking claw 12a of the locking lever 12 is engaged with the engagement groove 11 of the cam 10. The paper feed roller 6 is stopped and held with the flat portion 6b facing downward. Therefore, when the paper feed cassette 1 is attached or detached, the paper feed roller 6 does not interfere with the paper feed cassette 1 and the paper Y inside the paper feed cassette 1, and the attachment and detachment of the paper feed cassette 1 is not hindered.

When the operation command signal is input while the paper feed cassette 1 is mounted, the paper feed roller 6 and the cam 10 start rotating at a low speed as shown in FIG.
0 is released from the locked state by the locking lever 12, and as shown in FIG. 4B, it is gradually accelerated until the circular arc portion 6a of the paper feed roller 6 reaches a position where it contacts the paper Y. .. Here, as shown in FIG. 6, since the pulse motor 7 has a characteristic that the torque increases as the rotation speed decreases, when the cam 10 starts rotating,
Due to the large torque of the pulse motor 7 in the low speed state, the cam 10 is rotated against the locking holding force of the locking lever 12, and the cam 10 can be reliably released from the locked state.

Then, as shown in FIG.
4 is rotated to the position shown in FIG. 4B, the paper feed roller 6 is rotated at a constant speed at the paper feed speed. Therefore, the circular arc portion 6a of the paper feed roller 6 feeds the paper Y in the paper feed cassette 1 one by one.

Then, as shown in FIG. 4C, when the paper feed roller 6 is rotated until the contact of the arc portion 6a with the paper Y is completed, as shown in FIG. Is gradually decelerated and stopped in the state shown in FIG. Similarly, the cam 10 is gradually decelerated, and the main engaging portion 11a of the engaging groove 11 of the cam 10 engages with the engaging claw 12a of the engaging lever 12.
The rotation of the cam 10 is stopped when it is engaged with. At this time, immediately before the engagement groove 11 of the cam 10 is engaged with the locking claw 12a, the cam 10 is in the low speed state, so that when the locking groove 11 reaches the position of the locking claw 12a, The locking claw 12a surely engages in the locking groove 11 and holds the stop position of the cam 10.

In other words, due to the momentum of rotation of the cam 10, the locking groove 11 is not engaged with the locking claw 12a, and the position of the locking claw 12a is exceeded, so that the cam 10 rotates one rotation or more. The cam 10 can be reliably held at a predetermined stop position where the locking groove 11 and the locking claw 12a are engaged with each other without being damaged. Therefore, the paper feed roller 6 can be reliably stopped and held with the flat portion 6b facing downward, and the position when the rotation of the roller 6 is stopped can be always ensured.

Further, as described above, the positioning mechanism when the rotation of the paper feed roller 6 is stopped can be realized without using a sensor and a solenoid, unlike the prior art, so that the number of parts can be reduced and the structure can be improved. Simplification,
The production cost can be reduced.

[0021]

Another Embodiment Next, another embodiment of the present invention will be described with reference to FIG. Now, in this other embodiment, as shown in FIG. 7, as compared with the above-mentioned embodiment, instead of forming the engagement groove 11 on the peripheral surface of the cam 10, a contact member 19 is formed in a protruding manner, and its contact is made. A convex portion 19a is formed at the tip of the member 19. Further, instead of the locking lever 12 and the spring 14, a leaf spring 20 is fixed in the device frame, and a recess 20a is formed on the surface of the leaf spring 20 facing the contact member 19.

Then, when the operation of the apparatus is stopped and the sheet feeding operation is in a standby state, the convex portion 19a of the contact member 19 causes the leaf spring 2 to move.
0 of the paper feed roller 6 is engaged with the flat portion 6b.
Is stopped and held in a state where it faces downward. That is, the contact member 19 and the leaf spring 20 form a holding member.

When the paper feed roller 6 and the cam 10 start to rotate, the contact member 19 is rotated against the locking holding force of the leaf spring 20 due to the large torque of the pulse motor 7 in the low speed state. The contact member 19 can be reliably released from the locked state. Immediately before the paper feed roller 6 returns to the holding state, that is, the contact member 19 moves the leaf spring 2
Since the cam 10 is in a low speed state immediately before engaging with 0, when the contact member 19 approaches the position of the leaf spring 20, the convex portion 19a of the contact member 19 and the concave portion 20a of the leaf spring 20 are separated from each other. The cam 10 is securely engaged, and the stop position of the cam 10 is reliably retained. Therefore, as in the above-described embodiment, the paper feed roller 6 can be reliably stopped and held in the state where the flat portion 6b faces downward, and the position of the roller 6 when the rotation is stopped can be always made reliable. ..

The present invention is not limited to the above-described embodiment. For example, a servo motor other than the pulse motor 7 may be used, or the locking claw 12 at the tip of the locking lever 12 may be used.
It is also possible to embody the structure of each part by arbitrarily changing the configuration of each part without departing from the spirit of the present invention, for example, by configuring a by a roller so as to reduce frictional resistance during rotation of the cam 10. Is.

[0025]

As described above in detail, according to the present invention, the mechanism for positioning the stop position of the sheet feeding roller can be realized by a simple mechanism, the number of parts can be reduced, and the structure can be simplified.
It has the excellent effect of reducing production costs.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing an example of a sheet feeding device embodying the invention.

FIG. 2 is a partial sectional view of the sheet feeding device.

FIG. 3 is a block diagram showing a circuit configuration of components related to a sheet feeding operation of the sheet feeding device.

FIG. 4 is a partial cross-sectional view sequentially showing a rotation state of a paper feed roller and a cam.

FIG. 5 is a diagram showing changes in rotation speeds of a paper feed roller and a cam.

FIG. 6 is a diagram showing speed-torque characteristics of a pulse motor.

FIG. 7 is a partial sectional view showing another embodiment of the present invention.

[Explanation of symbols]

1 paper feed cassette, 6 paper feed rollers, 6b flat part, 7
Pulse motor, 10 cam as holding member, 12 locking lever as holding member, 14 spring as holding member, 15 CPU constituting control means, 16 ROM constituting control means, 18 rotation amount constituting control means A detector, 19 a contact member as a holding member, 20 a leaf spring as a holding member, and Y paper.

Claims (1)

[Claims] 1. A half-moon-shaped feed roller for feeding the sheets in the feed cassette one by one, a motor for rotating the feed roller, and a holding unit for holding the feed roller in a state where the flat portion thereof faces the sheet. A control for controlling the rotation of the motor so that the member and the paper feed roller are started to rotate at a low speed from the holding state, the holding is released, the paper speed is changed to the paper feeding speed, and then the speed is decelerated and stopped in the holding state. A sheet feeding device provided with means.