JPS5851259B2 - Sheet conveyance device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a sheet conveying device.

In a transfer type electronic copying machine, it is desirable that an unfixed toner image formed on a sheet be transported and fixed without rubbing.

When a pair of rollers is used as the sheet conveying means, there is a problem that unfixed toner images are disturbed.

2. Description of the Related Art A sheet conveying device using a sheet gripper that grips the leading edge of a sheet is already known as a means for conveying a sheet without rubbing a transferred toner image.

In this sheet conveying device, a sheet gripper is supported by a pair of chinos that rotate once and then stop, and the sheet gripper opens its grip claws at a starting position.

A sheet feed roller feeds the sheet into the sheet gripper whose gripping claws are open.

If the sheet is not fed reliably, the sheet gripper will not be able to reliably grip and convey the sheet.

First, an example of a conventional sheet conveying device will be described with reference to FIG. 1. Reference numeral 1 indicates a photosensitive drum that rotates in the direction of the arrow.

A toner image is formed on the surface of the photosensitive drum 1 via a copying unit (not shown).

A chain 3 for conveying a sheet gripper is disposed below the photoreceptor drum 1 and is hooked around a pair of sprockets 2 (one not shown). Both ends are fixed and supported.

The above-mentioned Cheno 3 is operated by a clutch mechanism (not shown).
It rotates once and stops at the starting position.

Therefore, the seat gripper 4 fixed to the ceno 3 also returns to the starting position after one rotation.

The sheet gripper 4 has a sheet gripping portion 5, a gripping claw 6 having a habit of coming into contact with the sheet gripping portion, and a cam follower 7 that swings the gripping claw against its habit.

Also, at the starting position of the sheet gripper 4 and on the rotational trajectory of the cam follower 7, there is a cam 8 for opening the grip claw.
is installed.

The sheet gripper 4 at the starting position is swung by the cam follower 7 coming into contact with the cam 8, causing the grip claw 6 to swing against its natural tendency, in other words, opening the claw.

The grip claw 6 is formed with a stopper 6a that abuts the leading end of the sheet being fed.

The grip claws 6 interposed above have sheet guides io and i1.
The end portions 9a of the seat passage 9 formed by the two sides are opposite to each other.

A constantly rotating roller 12 rotated by a drive device (not shown) is disposed above the seat path 9 with a part of its circumferential surface located in the seat path.

Idle rollers 13 are arranged below the constantly rotating rollers 12.

This roller 13 is rotatably supported by an arm 15 fixed to an operating shaft 14.

The operating shaft 14 is rotatably supported by a stationary member (not shown), and when the chino 3 starts rotating, it rotates counterclockwise in synchronization with this, and moves the idle roller 13 along the chain line 13A. As shown, it is oscillated so that it comes into contact with the normally rotating roller 12 and is driven to rotate.

At the right end of the sheet path 9, a sheet placing table 16 having a placing plate 16a on which the sheet S is placed is arranged, and a paper feed roller 17 is placed above it.

When the sheet S is fed, the placement plate 16a is raised by the lever 18 and brought into contact with the paper feed roller 17.

The paper feed roller 17 is rotated in the direction of the arrow by a drive mechanism (not shown) via a one-turn clutch (not shown).

Therefore, when a paper feed command is issued, it rotates once and then stops.

The circumferential length of the sheet feeding roller 17 is set to be slightly larger than the length l between the leading end Sa of the sheet S and the stopper 6a of the sheet gripper 4.

Now, when a paper feed command is issued, the paper feed roller 17 rotates once and sends out only one uppermost sheet S in the direction of arrow a.

The fed sheet stops when its leading end collides with the stopper 6a of the grip claw 6 of the sheet gripper 4.

At this time, the seat S is slightly bent due to the relationship L<l, and has a tendency to move in the direction of the arrow a due to the stiffness of the seat itself.

When a rotation command is issued to the cheno 3, the sheet gripper 4 starts moving in the direction of the arrow, and when the cam follower 7 comes off the cam 8, the grip claw 6 closes due to its habit and engages the sheet gripping part 5. Grip the tip of the sheet with.

In synchronization with the start of rotation of the chino 3, the operating shaft 14 rotates, swings the idle roller 13 as shown by the chain line 13A, and holds the sheet between the idle roller 13 and the normally rotating roller 12.

As a result, the sheet is conveyed in the direction indicated by the arrow while being fed by the sheet gripper 4, the constantly rotating rollers 12, and the idle rollers 13.

Even after the leading edge of the sheet S is fed into the sheet gripper 4, the sheet feeding roller 1T is in contact with the rear of the sheet S, so the gripping force of the sheet gripper 4 is insufficient for the constantly rotating rollers 12 and the idle rollers 13. , it is not possible to overcome the pressing force of the paper feed roller 17, so this is to assist this.

Therefore, when the sheet is conveyed, the paper feed roller 17 is adapted to be rotated by the sheet, and has a built-in one-way rotation clutch.

By the way, the grip claw 6 grips the leading end of the sheet not at the same time as the sheet gripper 4 starts to move, but when the cam follower 7 is disengaged from the cam 8.

That is, the sheet gripper 4 is moved a certain distance, for example, 3
When the sheet is moved n, the grip claws 6 close, and the sheet cannot be reliably gripped unless it is subjected to some kind of action for at least three distances.

Conventionally, due to the above relationship L<l, the sheet fed into the sheet gripper 4 is bent, giving the sheet a tendency to push against the sheet gripper 4, and when the gripper 4 starts moving, the sheet is bent. I was trying to follow.

However, the above-mentioned pushing behavior cannot always be expected for the sheet.

The rigidity of the sheet, so-called stiffness, is greatly affected by the environment, such as humidity, so it is impossible to expect uniform rigidity.

The present invention has been made in view of the above, and the present invention has been made in view of the above-mentioned problems.
It is an object of the present invention to provide a sheet conveying device capable of surely gripping the sheet and stably conveying the sheet by ensuring that the sheet follows the gripper.

The present invention will be explained below with reference to illustrated embodiments.

Note that parts having the same functions as conventional members are given the same reference numerals, and individual explanations are omitted.

In FIG. 2, the free end of a sheet pressing member 19 whose base portion 19a is fixed to a stationary member 20 is always elastically in contact with the normally rotating roller 12 protruding into the sheet path 9.

This sheet pressing member 19 is formed of a leaf spring.

Then, the pressing force of the sheet pressing member 19 to the normally rotating roller 12 passes between them and applies the tip Sa to the sheet gripper 4.
The feeding force is set so that when the fed sheet S is pressed by the constantly rotating rollers 12 and receives the feeding action thereof, the feeding force is such that the sheet does not buckle.

In other words, the sheet suppressing member 19 presses the sheet S against the constantly rotating rollers 12 so that the fed sheet S receives a feeding force toward the sheet gripper 4 due to friction with the constantly rotating rollers 12 to the extent that it does not buckle. It is something.

Now, when the paper feed roller 17 makes one revolution and sends out the sheet S, the sheet passes through the sheet path 9 and stops when its leading end Sa collides with the stopper 6a of the sheet gripper 4.

At this time, the sheet S is held between the constantly rotating rollers 12 and the sheet pressing member 19, and is given a feeding force directed toward the sheet gripper 4 by the rollers 12, in other words, pushing the sheet gripper 4.

Further, the fed sheet S is deflected due to the relationship of L>1, and this deflection sb is caused by the fact that the sheet
By being held between the sheet pressing member 19 and the sheet pressing member 19, the sheet is formed between the sheet feeding rollers 17 and the sheet feeding rollers 17.

Then, when the sheet gripper 4 starts to move in response to a movement command, the sheet leading end Sa follows this while abutting against the stopper 6a due to the above-mentioned pushing behavior.

Further, the idle roller 13 is raised in synchronization with the above command, and the sheet S is held and conveyed between this and the normally rotating roller 12.

When the cam follower 7 of the moving sheet gripper 4 comes off the cam 8, the grip claw 6 grips the leading edge of the sheet.

As described above, according to the sheet conveying device of the present invention, which is provided with a sheet suppressing member that presses the sheet against the constantly rotating rollers in order to apply a feeding force to the sheet fed into the sheet gripper to an extent that does not buckle the pushing side, When the sheet gripper moves, the sheet reliably follows it, so there is no possibility that the gripping claws fail to grasp the tip of the gripper.

Therefore, it is possible to obtain an apparatus that reliably transports sheets.

Furthermore, in the past, the idle roller 13 had to start operating as soon as possible after the sheet gripper 4 started moving, making it difficult to adjust the timing, but according to the present invention, the sheet gripper starts moving. When the sheet follows this, it is enough before the sheet deflection sb disappears, and the above-mentioned adjustment can be relatively rough.

Although a leaf spring is used as a means for pressing the sheet against the constantly rotating rollers in FIG. 2, the initial objective can also be achieved with the sheet pressing members shown in FIGS. 3 to 6.

In FIGS. 3 and 4, a roller 32 having an elastic brush 31 implanted therein is integrally provided on the end face of the idle roller 30. As shown in FIG.

As shown in FIG. 4, the tip of the brush 31 comes into contact with the circumferential surface of the constantly rotating roller 12 to press the sheet S against it when the idle roller 30 is in the separated position.

The brushes 31 may be provided at both ends of the idle roller 30, as shown in FIG. 5, or the idle roller may be divided into two parts and the brushes may be provided between them.

Furthermore, as shown in FIG. 6, the brush 31 may be replaced by a sheet suppressing member 60 made of sponge rubber.

In the above description, the normally rotating rollers are located above the seat passage 9, but the above-mentioned sheet pressing members can be used even if the rollers are disposed below the seat passage.

Next, in FIGS. 7 and 8, among the plurality of normally rotating rollers TO disposed below the seat passage 9, the support shaft 72 of the idle roller 71 is attached to the peripheral surface of the roller 70a that does not correspond to the idle roller 71. A roller 73 as a sheet suppressing member loosely fitted in is in contact with the roller 73 .

The hole 73a of the roller 73 is formed to have a diameter sufficient to allow the peripheral surface of the roller 73 to come into contact with the roller 70a even when the idle roller 71 is spaced apart from the normally rotating roller 70.

Then, the rollers 73 press the fed sheet S against the constantly rotating rollers 70a, and apply the same pushing force to the sheet as described above.

When the idle roller 71 operates, the idle roller 71 rotates as a result of the normally rotating roller 70 and feeds the sheet S.

In the example shown in FIGS. 7 and 8 above, the roller 73
When the sheet is pressed against the constantly rotating roller 0a, the roller 73
The mass of can be determined.

Furthermore, the surfaces of the rollers 73 and the normally rotating rollers 70a may be subjected to appropriate processing in consideration of the above-mentioned feeding force.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view showing a conventional example of the present invention, Fig. 2 is a front sectional view showing an embodiment of the invention, and Fig. 3 is a front view showing only the essential parts of an embodiment of the pond of the invention. , Figure 4 shows A- in Figure 3.
A sectional view taken along line A, FIGS. 5 and 6 are side sectional views showing only the essential parts of further embodiments of the pond of the present invention, and FIG. 7 is a front view showing only the essential parts of yet another embodiment of the present invention. , FIG. 8 is a partially sectional side view of the same. 4... Seat gripper, 6... Grip claw, 9... Seat passage, 12... Regularly rotating roller, 13... Idle roller , 11...
... Paper feed roller, 19 ... Sheet pressing member, 3
1... Brush, 60... Sponge rubber, 73... Coro.

Claims (1)

[Scope of Claims] 1. A Sealy gripper waiting with its grip claws open at a starting position, a paper feed roller that rotates via a one-turn clutch and feeds a sheet to the sheet gripper, and this paper feed roller. and the sheet gripper at the starting position, a normally rotating roller that is fixed above or below the sheet path and constantly rotates, and a normally rotating roller that is located below or above this normally rotating roller and that is located above or below the sheet path. When feeding the sheet to the sheet gripper, the sheet gripper is separated from the constantly rotating roller, and when the sheet gripper that has fed the sheet starts moving, it moves in the direction of coming into contact with the constantly rotating roller, pinching the sheet. In a sheet conveying device having an idle roller that rotates following the constantly rotating roller, the idle roller is in contact with the constantly rotating roller and has a tendency to press the sheet against the idle roller. A sheet pressing member is provided, and the sheet whose tip end is fed into the sheet gripper is held between the constantly rotating roller and the sheet pressing member to apply a feeding force to the sheet to the extent that the sheet does not buckle. Sheet conveyance device.