JP3606606B2 - Paper feeder - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a sheet feeding device that is mounted on an image forming apparatus such as a copying machine and reads an image while feeding a sheet material by a sheet feeding roller and a conveyance roller.
[0002]
[Prior art]
FIG. 5 is a schematic configuration diagram of a copying machine equipped with a conventional paper feeding device. A is a sheet feeding device mounted on the copying machine main body B, B1 is a photoconductor (drum), B2 and B3 are mirrors, C is a developing unit, D is a transfer / separation unit, E is a fixing unit, and F is a feeding unit. Paper section.
[0003]
FIG. 6 is a schematic configuration diagram of the paper feeding device of FIG. In the figure, a roller driving means for rotating a pair of paper feed roller pairs (consisting of a paper feed roller 8 and a presser roller 9) for feeding a sheet material (original) P is not shown. Between the feed roller 8 and the presser roller 9, the feed roller 8 and the presser roller 9 are pressed against each other and the original P is sandwiched between them. A document feeding solenoid 5 is provided as a sheet feeding switching means for switching to a retracted state where the document P is not fed at a distance.
[0004]
The document P is inserted between the upper guide 1 and the lower guide 2, and the front end is brought into contact with the shutter 3. At this time, the document detection sensor 4 detects the document P, and the document feed solenoid 5 is turned on after a predetermined time Δt1 (FIG. 8).
[0005]
As a result, in the solenoid link mechanism 6, the roller holding lever 16 rotates about the support shaft 7 in the counterclockwise direction S in the figure via the support lever 17 and the spring 18. Accordingly, since the lever locking pin 21 provided in the gabox 20 is locked by the roller holding lever 16, it rotates around the central axis 22 of the roller 10 and the paper feed roller 8 is pressed against the presser roller 9. The document P is lowered until it abuts against the presser roller 9, and the document P is sandwiched between the presser roller 9.
[0006]
At the same time, as shown in FIG. 7, the shutter 3 is actuated in a direction to open the document conveyance path formed by the upper and lower guides 1 and 2 by means such as a solenoid (not shown). The operation of the solenoid link mechanism 6 is restricted by the stopper 19.
[0007]
After a predetermined time Δt2 (FIG. 8) after the document feed solenoid 5 is turned on, a motor (not shown) as a roller driving means starts rotating, and the feed roller 8 and the transport roller. The rollers 10 and 11 and the paper discharge roller 12 start to rotate. By the way, the motor and the four rollers 10 to 12 are all connected by belt driving or gear driving, and the document P is fed until it hits the registration shutter 13 as shown in FIG. .
[0008]
At this time, the pre-registration original detection sensor 14 is turned off, and after a sufficient time Δt3 (FIG. 8) for the original P to hit the registration shutter 13, the motor is temporarily stopped and the transfer on the copier body B side is performed. It waits for paper to be fed from the paper feed unit F.
[0009]
When paper feeding on the copying machine main body B side is completed, the lamp 15 is turned on, and then the motor starts to rotate again after a predetermined time Δt4 (FIG. 8). When the resist shutter solenoid (not shown) is turned on after a predetermined time Δt5 from the restart of the motor, the resist shutter 13 is actuated to open the document transport path composed of the upper guide 1 and the lower guide 2.
[0010]
Accordingly, the document P is irradiated by the lamp 15 while being transported by the transport rollers 10 and 11 and the paper discharge roller 12, and as shown in FIG. 5, it passes through the mirrors B1 and B2 along the chain line path. An image of the original is formed on the photoconductor B1 on the copier body B side.
[0011]
[Problems to be solved by the invention]
However, the conventional example has the following problems.
[0012]
The time Δt5 from when the motor is started to accurately align the leading edge of the image with the transfer paper until the registration shutter 13 is opened is the time Δtm required for the motor to reach a constant rotational speed. Must be larger than (FIG. 9). During this time Δt5, the paper feed roller 8 is in a paper feed state, and a conveying force is applied to the original P.
[0013]
On the other hand, since the leading edge of the document P is pressed by the registration shutter 13 due to the restriction of the leading edge, the paper feed roller 8 slips on the document P. For this,
(1) The original P is pressed against the registration shutter 13 and the leading edge of the original P is damaged. (2) The roller traces of the paper feed roller 8 are attached to the original P, and the dirt on the rollers adheres to the original P. There was a problem of soiling.
[0014]
An object of the present invention is to improve the above-described problems, in which the time when the paper feed roller slips on the original is small, no roller marks are left on the original, the original is less damaged, and the original is not displaced. It is an object of the present invention to provide a paper feeding device that is prevented.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a paper feeding apparatus having a paper feeding roller for feeding a sheet material and a roller driving means for rotating the paper feeding roller. A feeding state for feeding the sheet material and a retracting state for not feeding the sheet material are provided. After the sheet feeding roller is rotated for a predetermined time in the retracted state, the sheet feeding roller is set to the sheet feeding state. A sheet feeding device comprising sheet feeding switching means for switching.
[0016]
According to the present invention, a paper feed having a pair or a plurality of paper feed roller pairs for feeding a sheet material and a roller driving means for rotating at least one of the paper feed roller pairs. In the apparatus, holding release means for releasing the holding of the sheet material is provided in the vicinity of the sheet feeding roller pair, the sheet feeding roller pair is pressed against each other, and the sheet material is sandwiched between the sheet feeding roller pairs. The sheet feeding roller pair is separated from the sheet feeding roller pair and a retreating state in which the sheet material is not fed is provided, and the sheet material is predetermined by the sheet feeding roller pair in the sheet feeding state. Then, the sheet feeding roller pair is switched to the retracted state, the sheet material is held by the holding release means, and the sheet feeding roller pair is retracted for a predetermined time. And a sheet feed switching means for releasing the holding of the sheet material after the rotation and switching to the sheet feeding state again.
[0017]
According to the present invention, the predetermined time is at least the time required for the paper feed roller to start rotating and stabilize.
[0018]
[Action]
By adopting the paper feeding device of the present invention, the paper feeding roller is retracted and rotated for a predetermined time necessary for the motor to reach a constant rotational speed, and then the paper feeding roller is fed. The sheet material is fed by switching to the state, and the sheet material is fed by a predetermined length by the pair of feeding rollers in the feeding state, and then the feeding roller is switched to the retracted state. The sheet material is held on the sheet material by holding the sheet material and rotating the paper feed roller for a predetermined time, then releasing the sheet material and switching to the paper feed state again. The sheet is not slipping for a short time, and the sheet material does not have a roller mark, and the sheet material is less damaged and misalignment is prevented.
[0019]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0020]
FIG. 1 is a schematic configuration diagram of one embodiment of the present invention, and FIG. 2 shows an operation sequence of FIG. In FIG. 1, 2, the same code | symbol is attached | subjected to the part which has the same function as FIG. As in FIG. 7, the pre-registration sensor 14 is turned off by feeding the sheet material (original) P, and the motor (not shown) is stopped after a predetermined time Δt3.
[0021]
This motor restarts after the paper feeding on the copier body B side is completed. Between this stop and restart, the document feed solenoid 5 is temporarily turned off (FIG. 2). When the solenoid 5 is turned off, the paper feed roller 8 is once separated from the original P and in a retracted state. In this retracted state, the paper feed roller 8 restarts.
[0022]
Thereafter, after a predetermined time Δt6, the document feed solenoid 5 is turned on to pressurize the feed roller 8 onto the document P, and at the same time, the registration shutter 13 is released and the document P is fed. Become. The predetermined time Δt6 has the relationship of the following equation (1) with the predetermined times Δt5 (FIG. 2) and Δtm (FIG. 9).
[0023]
△ t6 <△ t5, △ t6> △ tm ………… (1)
In this way, the predetermined time Δt6 is set longer than the time tm until the paper feed roller 8 reaches a certain number of revolutions, and during this time the paper feed roller 8 is separated from the original P and is in the retracted state. The slip time on P is reduced, and the adherence of dirt is reduced without damaging the original P.
[0024]
FIG. 3 shows a schematic configuration diagram of another embodiment of the present invention. In the drawing, the shutter opening / closing mechanism 23 of the present embodiment, which is a holding release unit for the original P, can open and close the shutter 3 provided near the paper feed roller 8 and the presser roller 9 simultaneously with the paper feed roller 8. To do.
[0025]
For this purpose, the shutter opening / closing mechanism 23 is provided so that the shutter 3 can be rotated by a support shaft 25, and the shutter 3 is attached to the other end of a mounting member 26 provided at one end of the support shaft 7 of the solenoid link mechanism 6. The connection member 27 is connected.
[0026]
With this configuration, in the retracted state in which the paper feed roller 8 is lifted by the roller holding lever 16, the shutter 3 is lowered (FIG. 4), and the paper feed roller 8 is lowered and the original document is lowered. In the paper feeding state in which P is held between the press roller 9 and the shutter 3, the shutter 3 is raised (FIG. 3).
[0027]
Accordingly, the solenoid link mechanism 6 and the shutter opening / closing mechanism 23 are operated by the single document feed solenoid 5, and after the document P comes into contact with the registration shutter 13, the document feed roller 8 is temporarily removed from the document P. When the shutter 3 is retracted, the shutter 3 serves as a holding unit for holding the document P, and prevents the document P whose tip is regulated by the resist shutter 13 from being displaced.
[0028]
In addition, this invention is not limited to the said Example, It is possible to implement in another aspect by making an appropriate design change.
[0029]
【The invention's effect】
As is apparent from the above description, the paper feeding device of the present invention is configured so that the paper feeding roller is retracted and rotated for a predetermined time necessary for the motor to reach a certain number of revolutions. Switch the roller to the paper feed state to feed the original, feed the original by a predetermined length by the paper feed roller in the paper feed state, then switch the paper feed roller to the retracted state, By holding the original and rotating the paper feed roller for a predetermined time and then releasing the paper holding and switching to the paper feed state again, the problems of the prior art can be easily solved, and the paper -Since the time during which the roller slips is reduced, there are no roller marks on the original, the original is less damaged, and the original is prevented from being misaligned.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.
FIG. 2 is an operation sequence of FIG. 1;
3 is an operation state diagram of FIG. 1. FIG.
4 is another operational state diagram of FIG. 1. FIG.
FIG. 5 is a schematic configuration diagram of a conventional image forming apparatus.
6 is a diagram illustrating a sheet feeding operation state in FIG. 5;
7 is another state of the paper feeding operation in FIG.
8 is an operation sequence of FIG. 6;
FIG. 9 is a rotational speed curve diagram with respect to time of a driving motor.
[Explanation of symbols]
1 Upper guide 2 Lower guide 3 Shutter 4 Document detection sensor 5 Document feed solenoid 6 Solenoid link mechanism 7 Support shaft 8 Feed roller 13 Registration shutter 14 Pre-registration sensor 15 Lamp 16 Roller holding lever
17 Support lever
18 Spring 23 Shutter opening / closing mechanism A Paper feeder B Copy machine body

Claims (3)

In a sheet feeding device having a sheet feeding roller for feeding a sheet material and a roller driving means for rotating the sheet feeding roller, a feeding state for feeding the sheet material; A retreat state that does not feed,
The paper feed in the feeding the sheet material B - to the retracted state was stopped La, after the sheet feeding roller of the retracted state is rotated a predetermined time, said feed path - the paper feed La state A sheet feeding device comprising sheet feeding switching means for switching between the two. A sheet feeding apparatus having a pair of sheet feeding rollers for feeding a sheet material and a roller driving means for rotating at least one of the sheet feeding roller pair. A holding release means for releasing the holding of the sheet material is provided in the vicinity of the roller pair, and a feeding state in which the sheet feeding roller pair is pressed against each other and fed with the sheet material interposed therebetween the paper feed Russia - to separate the roller pair the sheet - providing a retracted state without feeding the door member, the sheet - the door member the paper feed b of the feeding state - by roller pair feeds a predetermined length Then, the sheet feeding roller is switched to the retracted state, the sheet material is held by the holding release means, and the sheet feeding roller pair is rotated in the retracted state for a predetermined time, and then the sheet roller is retained. A sheet feeding device comprising sheet feeding switching means for releasing the holding of the material and switching to the sheet feeding state again. 3. The sheet feeding device according to claim 1, wherein the predetermined time is at least a time necessary for the rotation of the sheet feeding roller to start and stabilize.

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