JPS62264159A - Paper feed device for copying machine - Google Patents

Abstract

PURPOSE:To improve transfer precision by providing a curling means for giving curvature to copying paper in the carrying passage thereof and improving adherence between the paper and a transfer drum. CONSTITUTION:Before copying paper has been carried to a main carrier passage 22 and the trailing end thereof has been released from a reversal roller 14a, the rotary motion of the roller 14a is stopped. Then, a reversing lever 25 is moved to the inside of the main carrier passage 22 and thereafter the reversal roller 14a is made to rotate in a reverse direction, thereby carrying temporarily the copying paper 10 forcibly in a reverse direction toward the reversing lever 25 and giving the paper 10 curvature in the same direction as a transfer drum 19. Furthermore, the copying paper 10 is carried between a reversal roller 14b and a sub-reversal roller 15, led to a reversal carrier passage 23 and given secondary curvature by the curved part 24a of a guide plate 24. Then, the copying paper 10 is clamped with the clamping claw 18 of the transfer drum 19 and paper with a pair of resist rollers 16. In this case, the copying paper 10 as suitably curled is fixed close along the transfer drum 19 due to electrostatic action with a dielectric film 17.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a paper feeding device applicable to a copying machine having a transfer drum.

(Prior art) Conventionally, in color copying machines that employ a three-color sequential overlay method, the latent image and transfer paper are generally aligned by wrapping the transfer paper around a transfer drum and fixing it. It has been implemented.

For example, as shown in FIG.
Alternatively, in addition to pasting a mesh, clamping claws 5 are provided to clamp the transfer paper 4 between the surface of the dielectric film 3, and the film 3 is charged and transferred so that the transfer paper 4 is easily wrapped around the transfer drum 2. The paper 4 and the film 3 are brought into close contact with each other by electrostatic action.

That is, in FIG. 10, it is placed in front of the transfer drum 2! The transfer paper 4 conveyed through the registration roller pair 6 is gripped by the gripping claws 5 by the operation of a cam mechanism (not shown), and is brought into close contact with the transfer drum 2 by the electrostatic action of the film 3 described above. After the transfer process is completed, in the separation process, the gripping claws 5 are opened by the operation of the cam mechanism, and the transfer paper 4 is moved onto the conveyor belt by the action of the elastic force of the transfer paper 4 itself, the strength of the so-called "resilience". 7 and is sent to a fixing section (not shown).

However, in the conventional bag Tl described above, it is not possible to bring the stiff transfer paper 4 such as a postcard or cardboard into close contact with the film 3 only by the electrostatic action, and as shown in FIG. 4 may be separated.

For this reason, not only is it not possible to obtain good transfer, but the transfer paper 4
There are problems in that the unfixed image on the transfer paper comes into contact with members around the transfer drum 3, or the relative position between the transfer drum 3 and the transfer paper 4 changes, making it impossible to achieve good alignment. Ta.

(Objective) It is an object of the present invention to provide a paper feed device for a copying machine that can solve the problems of the prior art described above, improve the adhesion between the transfer drum and the transfer paper, and improve the transfer accuracy. do.

(Structure) In order to achieve the above-mentioned object, the present invention is characterized in that a copying machine having a transfer drum is provided with curling means for imparting curvature to the transfer paper in the conveyance path of the transfer paper. .

Hereinafter, the present invention will be specifically explained based on preferred embodiments.

First, a first embodiment of the present invention will be described based on FIG. 1 to FIG. 2(e).

In the front view of the first embodiment shown in FIG.
Above the cassette 11 that stores 0, there is a calling roller 12.
A pair of rollers 13 consisting of a conveyance roller 13a and a separation roller 13b is arranged in front of the calling roller 12, and in front of this pair of rollers 13, A pair of reversing rollers 14a and 14b,
A sub-reversing roller 15 is arranged to be in contact with the lower reversing roller 14b. Further on the other side, there is a pair of known registration rollers 16, a dielectric film 17 on the outer peripheral surface, and a clamping claw 18.
and a transfer drum 19 are arranged in sequence, and the transfer drum 19 is arranged so as to be in contact with the photoreceptor drum 20.

A main transport path 22 for the transfer paper 10 is formed by a guide plate 21 between each of the roller pair 13, reversing roller pair 14a, 14b, registration roller pair 16, and transfer drum 19. By the way, a reversing conveyance path 23 separate from the main conveyance path 22 is formed by a guide plate 24 at the portions of the reversing roller pair 4at 14b and the sub reversing roller 15.

That is, the sub-reversing roller 15 and the lower reversing roller 14
The guide plate 24 below the joint with the curved portion 24a
, and a guide F on the opposite side to this curved portion 24a.
The i24 end 24b extends to the joint of the pair of registration rollers 16. And reversing roller pair 14a, 14b
A reversing lever 2 is provided on the main conveyance path 22 between the roller pair 13 and the roller pair 13.
5 is provided so as to be retractable, and the pair of reversing rollers 14
a.

14b, the auxiliary reversing roller 15, the guide plate 24 having the curved portion 24a, and the reversing lever 25 constitute a curl imparting means for imparting a curvature to the transfer paper 10.

Next, the operation of the above-described embodiment will be explained.

The transfer drum 19 is rotated by a drive system (not shown), and when the gripping claw 18 comes to a predetermined position by a position detection device (not shown) for the gripping claw 18, the transfer paper loaded in the cassette 11 (in this embodiment As shown in FIG. 2 (al), the transport roller 13a and the separation roller 1
3b, where the transfer paper 10 is completely separated into one sheet and sent to the next reversing roller pair 14a, 14b. At this time, the reversing lever 25 is held at a position away from the main conveyance path 22. The upper reversing roller 14a is rotating and stops rotating before the rear end of the transfer paper 10 leaves the reversing roller 14a.

This stop is braked differently depending on the size of the transfer paper 10, but it is possible to control the size of the transfer paper 10 to be fed.
The rotation angle of the reversing roller 14a is controlled based on the read signal by a controller (not shown).

Next, as shown in Fig. 2, the reversing lever 25 is moved into the main conveyance path 22, and then
Rotate a in the opposite direction. Then, the transfer paper 10 is moved to the reversing lever 25
It is conveyed in the opposite direction and comes into contact with the reversing lever 25.

This reversing lever 25 has a curvature approximately equal to that of the upper reversing roller 14a, and the transfer paper l
By forcibly changing the direction of O, the transfer paper 10
is given a curvature in the same direction as the transfer drum 19, and the first curling is performed.

Further, as shown in FIG. 2(C), the transfer paper IO is transferred to the lower reversing roller 14 which is driven by the upper reversing roller 14a.
b and the sub-reversing roller 15, and the reversing conveyance path 2
3, and a second curling is performed by the curved portion 24a of the guide plate 24 during conveyance.

Then, as shown in FIG. 2 (d+), the transfer paper 10 is conveyed by the reversing roller 14b until its leading edge abuts against the pair of registration rollers 16, and then the transfer paper 10 is conveyed by the reversing roller 14b, and
When it reaches a predetermined position, the registration roller pair 16 rotates,
C: Clamping the leading edge of the transfer paper 10 with the clamping claws 1a
V bite in the min.

Then, as shown in FIG. 2(e), since the transfer paper 10 is curled appropriately, the ζ-transfer transfer 10 or the transfer drum 19 is brought into close contact with the transfer drum 19 due to the electrostatic action with the dielectric film 17. It turns out. - Good transfer can be obtained because of the second method, and the transfer is of good image quality with no positional shift or image rubbing.

Furthermore, the transfer paper 10 which is not stiff needs to be passed only through the main conveyance path 22, and the reverse rotation of the pair of reversing rollers 14a and 14b for conveying it to the reversing conveyance path 23 is not performed.

Next, a second embodiment of the present invention will be described based on FIGS. 3 to 5(C). Incidentally, members corresponding to those of the first embodiment described in FIGS. 1 to 2 are given the same reference numerals.

The difference between this second embodiment and the first embodiment is as follows.
A curling means including a pair of elastic rollers 30 is provided between the pair of rollers 13 and the pair of registration rollers 16.

That is, of the elastic roller pair 30, the upper [7-ra 30
The roller a is made of a material harder than the lower roller 30b. For example, as shown in FIG. 4, it is conceivable to use a metal roller for the upper roller 30a and a lower roller 30b in which the core is a metal roller A and the outer periphery is covered with a layer of rubber material B.

Due to the above-mentioned hardness difference, when the part B of the rubber 12 of the lower roller 30b is pressed by the upper roller 30a, it deforms within the range of the nip width C, which is the contact area. Transfer paper 1 within this nip width C
When the transfer paper 10 is conveyed, the deformation between the pair of elastic rollers 30 causes the transfer paper 10 to be curled in the direction of the harder roller.

Therefore, the transfer paper 10 is curled in the same direction as the curvature of the transfer drum 19 by the pair of elastic rollers 30, and its adhesion to the transfer drum 19 can be improved as in the first embodiment.

It is also conceivable that the registration roller pair 1G has the same structure as the elastic roller pair 30 described above.

Furthermore, in the second embodiment, FIG. 5(a), fbl,
As in the adjusted state of the elastic roller pair 30 shown in (C),
An adjustment lever 31 is rotatably provided on either the upper roller 30a or the lower roller 30b, and the adjustment lever 3
1, the pressing force of the upper roller 30a and lower roller 30b is made variable, and the nip width and amount of deformation are changed depending on the type of transfer paper 10 (ie, single paper, cardboard, leaf), etc. Therefore, the amount of curl can be adjusted according to the degree of stiffness E of the transfer paper 10 so that it can be wrapped around the transfer drum 19 well.

Of course, the above-mentioned adjustment of the amount of curl of the transfer paper may be automatically performed by automatically detecting the quality of the transfer paper.

Next, a third embodiment of the present invention will be described based on FIGS. 7 to 9. Incidentally, members corresponding to those of the first embodiment described in FIGS. 1 to 2 (el) are given the same reference numerals.

The first thing already mentioned. The difference from the second embodiment is that a heating roller pair 4 is provided between the roller pair 13 and the registration roller pair 16.
The present invention has a structure in which a curling means consisting of 0 is provided.

That is, as shown in FIG. 7, the heating roller pair 40 uses a cylindrical body 42 having a heater 41 such as a halogen heater inside as the upper roller 40a, and the lower roller 40b has a general roller structure. .

Therefore, when the transfer paper 10 is conveyed to the heating roller pair 40, the upper roller 40a is heated to a predetermined temperature by the heater 41 according to the paper quality of the transfer paper 10.
When the upper roller 4'Oa side of the transfer paper 10 is heated, the moisture contained in the transfer paper 10 becomes uneven, and the transfer paper 10 curls toward the upper roller 40a side.

In this way, the transfer paper 10 is curled in the same direction as the curvature of the transfer drum 19 by the heating roller pair 40, and the first curl is applied to the transfer paper 10 in the same direction as the curvature of the transfer drum 19. Similar to the second embodiment, the adhesion to the transfer drum 19 can be improved.

Further, as shown in FIG. 8, instead of the elastic roller pair 30, a fixed heater 43 may be simply disposed in a part of the conveyance path 22.

Furthermore, it is also conceivable to use the structure of the elastic roller pair 30 in the second embodiment in combination with the third embodiment. That is, as shown in FIG. 9, the heater 4 is installed inside the upper roller 44.
1 built-in, the lower roller 45 is composed of a core bar 45a and a rubber layer body 45b fixed to the outside of the core bar 453, and the rubber layer body 45b of the lower roller 45 is formed by the upper roller 44.
to be deformed by pressure.

By doing so, heat and elastic deformation force are applied to the transfer paper lO, making it more likely to curl.

(Effects) As described above, the present invention provides a paper feeding device that can contribute to improving transfer quality because a curvature is imparted to the transfer drum so that it comes into close contact with the transfer drum.

[Brief explanation of drawings]

FIG. 1 is a front view of the first embodiment of the present invention, FIG. 2(a),
Figure 2 (hL@Figure 2 (C), Figure 2 (d), Figure 2 te
＞ is a diagram explaining the operation process of the first embodiment, FIG. 3 is a front view of the second embodiment of the present invention, FIG. 4 is an enlarged front view of the main part of the second embodiment, and FIG. ), Figure 5 middle), Figure 5 (C)
6 is a front view of the third embodiment of the present invention, FIG. 7 is an enlarged sectional view of the main part of the third embodiment, and FIG. 8 is a first modification of the third embodiment. FIG. 9 is a sectional view of a main part showing a second modification of the third embodiment, FIG. 1O is a perspective view of a conventional example, and FIG. 11 is a diagram for explaining the operating state of the conventional example It is a diagram. 10--Transfer paper, 14a, 14b, 15.24a. 25.30, 40, 43, 44.45... Curling means, 19... Transfer drum, 22.23... Conveyance path. Figure 1 Figure 2 (q) Figure 2 (b) Figure 2 (c) Figure 2 (d) Figure 2 (e) Figure 4 Figure 5 (0) Figure 5 (b) Figure 5 (c) Figure 7 Figure 9

Claims (1)

[Claims] 1. A paper feeding device for a copying machine having a transfer drum, characterized in that a curling means for imparting a curvature to the transfer paper is provided in a transport path of the transfer paper.