JPH01252426A - Image forming device - Google Patents

Abstract

PURPOSE:To integrate a material to be transferred into an integrating part without curl by providing first and second direction changing parts which direct the conveying directions thereof reversely each other. CONSTITUTION:In a conveying passage 35 inside a conveying unit 31, a first curve part 35a is provided at its one end as a first direction changing member, while a second curve part 35b at the other end as a second direction changing member. They are curved in a reverse manner each other, and the passage 35 is formed substantially of S shape. In forming images on both faces, a sorting gate 32 is rotated upward, a sheet P having image at its one side is introduced into the passage 35 and conveyed. The sheet P is curled along the curve direction after it passes through the part 35a, but it is curved in the reverse direction with respect to the part 35a, thus the curl is corrected, and the sheet is stored into an accommodation member 40 without curl.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an image forming apparatus capable of forming an image on a transfer material multiple times, for example, in double-sided copying.

(Prior Art) As is well known, electronic copying machines capable of copying images on both sides of paper have been developed. There is something.

In the figure, a is the main body of the copying machine, and a transport unit b for paper P is provided at the bottom of the main body a of the copying machine. The image of the first original document is transferred to the paper P by the action of the transfer charger d, and this paper P is transferred to the paper P by the action of the transfer charger d.
The film is peeled off from the photosensitive drum C by the action of . Then,
This paper P is sent to a fixing roller j via a conveyor belt i, where the image is fixed, and then ejected via an ejection roller k. and is stored in a stacker (accumulating section) n via this conveyance path m. Thereafter, the sheets P are sequentially stacked in the stacker n in the same manner. In this way,
When the stacking of the sheets P is completed, the sheets P are taken out one by one by the pickup roller 0 according to the exposure scan of the second document, passed through the feed roller p and the switching gate q, and sent to the switchback roller r. It will be done. After that, this switchback crawler r rotates in the reverse direction, and the paper P is inverted and moved to the aligning roller S in the copying machine main body a.
There, the document is aligned and sent again between the photosensitive drum C and the transfer charger d, the image of the second document is transferred to the opposite surface, and the document is ejected to the outside of the copying machine body a. Ru.

(Problem 8 to be Solved by the Invention) However, in the past, the paper P transported along the transport path m has its transport direction changed only in one direction. n
was housed inside.

Therefore, when the paper P is taken out from the stacker 〇 and conveyed, the paper P is conveyed in a curled state, resulting in a problem that a paper jam occurs in the conveyance path.

The present invention has been made in view of the above, and an object of the present invention is to provide an image forming apparatus that prevents curling of a transfer material and prevents paper jams from occurring.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention transfers an image onto a transfer material in an image forming section, and then transfers this transfer material through a conveyance path. The material to be transferred is accumulated in a stacking section, and the transferred material accumulated in this stacking section is conveyed again to the image forming section to transfer the image, and the conveyance path is configured such that the conveying direction of the transferred material is in opposite directions. The present invention is characterized by having first and second direction changing portions for changing the direction.

(Function) By changing the direction of the transferred material conveyed along the conveyance path in opposite directions at the first and second direction changing sections, curls formed at the first direction changing section are removed by the second direction changing section. This is corrected at the direction changing section so that the paper can be stacked in the stacking section without curling.

(Example) The present invention will be described below with reference to an example shown in FIG.

FIG. 1 schematically shows an image forming apparatus of the present invention, such as a copying machine.

In the figure, reference numeral 1 denotes a copying machine main body, and a document table (transparent glass) 2 is fixed to the upper surface of the copying machine main body 1 for holding a document. This document table 2 is provided with a fixed scale 21 that serves as a reference for setting the document, and furthermore, a document cover 11 that can be opened and closed is provided near the document table 2. The original placed on the original table 2 is exposed to an exposure lamp 4, a mirror 5.
By reciprocating an optical system consisting of 6.7 and 6.7 along the lower surface of the document table 2, exposure scanning is performed.

In this case, mirror 6.7 moves at half the speed of mirror 5 so as to maintain the optical path length. The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the light irradiation of the exposure lamp 4, is reflected by the mirror 5, 6, 7, passes through the variable magnification lens block 8, and further passes through the mirror 91. .9□, 93 and guided to the photosensitive drum 10 as an image forming section, so that an image of the document is formed on the surface of the photosensitive drum 10.

The photosensitive drum 10 rotates in the direction of the arrow a in the figure, and the surface is first charged by the charging device 11, and then the image is exposed to slit light at the exposure section ph, thereby forming an electrostatic latent image on the surface. be done.

This electrostatic latent image is produced by a developing device 12 that contains, for example, red or black toner, and is selectively operated as required.
1.122, the image is visualized by adhering toner.

On the other hand, sheets of paper (material to be transferred) are taken out one by one from the selected upper paper feed cassette 131 or lower paper feed cassette 132 by a feed roller 141, 142 and a pair of rollers 151, 152, The image is guided through the image to a pair of registration rollers 17, and guided to a transfer section by the pair of registration rollers 17.

Here, the paper feed cassette 13. ．． 132 is detachably provided at the lower right end of the copying machine main body 1, and one of them can be selected from an operation panel (not shown). In addition, each of the above paper feed cassettes 13□, 1
32 are respective cassette size detection switches 601.
The cassette size is detected by 602. This cassette size detection switch 601-60
□ is composed of a plurality of microswitches that are turned on and off according to the insertion of cassettes of different sizes.

Furthermore, a manual feed guide 13a is provided on the upper surface of the paper feed cassette 131.
The paper manually inserted through the feed roller 14a
The sheet is guided to the pair of rollers 151 by the roller pair 151, and is then conveyed in the same manner as sheets fed from the sheet feed cassette 131.

On the other hand, the paper sent to the transfer section comes into close contact with the surface of the photoreceptor drum 10 at the transfer charger 18, so that the toner image on the photoreceptor drum 10 is transferred by the action of the charger 18. . This transferred paper is transferred to a non-peelable charger 19.
The toner image is electrostatically peeled off from the photoreceptor drum 10 and conveyed by the conveyor belt 20, and is fixed by passing through a fixing roller 21 provided at the terminal end of the toner image.

After this fixing, the paper is discharged to the outside of the copying machine main body 1 by a pair of delivery rollers 22. Further, after the transfer, the residual toner on the surface of the two-photo drum 10 is removed by a cleaner 24, and the residual image is erased by a static elimination lamp 25, so that the two-photo drum 10 returns to its initial state.

Note that 26 is a cooling fan for preventing a rise in temperature within the main body 1 of the copying machine. In addition, the exposure lamp 4, the mirror 5
is provided on the first carriage 28a, and the mirror 6.7 is provided on the second carriage 28b.

On the other hand, the copying machine main body 1 is provided with a conveying unit 31 that constitutes a conveying means.

The transport unit 31 is provided with a gate 32 for guiding the paper discharged by the pair of delivery rollers 22 of the copying machine main body 1 into the transport unit 31 or out of the transport unit 31. . This distribution is gate 32
A pair of feed rollers 33 is provided near the pair of feed rollers 33 , and the sheets guided to the pair of feed rollers 33 by the gate 32 are ejected to a paper ejection tray 34 provided outside the transport unit 31 . Ru.

Further, the distribution is carried out by the gate 32 on the transport unit 31.
The paper guided inside is guided to a conveyance path 35. Pairs of rollers 36, 37, 38, and 39 are provided on the conveyance path 35 at a predetermined distance from each other, and the sheets conveyed by these pairs of rollers 36 to 39 are stored in a storage section 40 serving as a stacking section.

This housing portion 40 is provided with a stopper 41 . A screw 42 rotated by a motor (not shown) is screwed into the stopper 41, and as the screw 42 is rotated, the paper is moved to a position corresponding to the size of the paper. Further, a take-out roller 43 is provided near the storage section 40 to take out the paper stored in the storage section 40 . This take-out roller 43 is provided on a rotatable support body 44, and when storing the paper in the storage section 40, the support body 44
is rotated to the state shown by the solid line in the drawing, and when the paper stored in the storage section 40 is to be taken out, it is turned to the state shown by the dotted line in the drawing.

The sheets taken out from the storage section 40 by the take-out roller 43 are led to a first conveyance path 46 via a separation roller 45 that separates and conveys the sheets one by one. This first
A feed roller 47 is provided in the middle of the conveyance path 46 , and the paper conveyed by the separation roller 45 is conveyed to the copying machine main body 1 by the feed roller 47 .

On the other hand, the transport unit 31 includes a large capacity paper feed cassette 48.
is installed. A take-out roller 49 is provided near the large-capacity full paper feed cassette 48, and the take-out roller 49 is provided on a rotatable support 49a. The paper taken out by the take-out roller 49 is guided to the copying machine main body 1 via a separation roller 50 and a second conveyance path 51.

The eleventh second transport path 46. The scraped paper is moved onto the photoreceptor drum 1 by a pair of registration rollers 17 that are operated in synchronization with the exposure scan of the original.
0 and the transfer charger 18.

Furthermore, an opening 52 is provided in the first and second transport paths 46,51 located within the transport unit 31 so as to communicate with each other. Opposed to this opening 52, a light emitting element 53,
A paper detector 55 consisting of a light receiving element 54 is provided, and the paper detector 55 detects the first and second transport paths 46.
．． 51 is detected. The detection output of the paper detector 55 is supplied to a control unit (not shown) to be described later, and the control unit (not shown) controls the detection output of the paper detector 55, for example, to Paper feeding errors are now detected.

By the way, the conveyance path 35 provided in the conveyance unit 31 has a first curved section 35a as a first direction changing section at one end thereof and a second curved section 35a as a second direction changing section at the other end thereof. 35b is formed. the first and second curved portions 35a;

35b are curved in opposite directions, and the conveyance path 35 is formed into a substantially S-shape.

Thus, during double-sided image formation, the gate 32 is rotated upward for sorting, and the sheet P on which the image is formed on the negative side is introduced into the conveyance path 35 and conveyed.

During this conveyance, the sheet P first passes through the ml curved section 35a and becomes curled along the curved direction, but when it passes through the second curved section 35b, it curls in the first curved direction. It is curved in the opposite direction to the portion 35a to correct the curl, and is accommodated in the storage portion 40 in a curl-free state. The sheets P... accumulated in the storage section 40 are taken out by a take-out roller 43, separated one by one by a separation roller 45, and sent to a feed roller 47.
The feed roller 47 sends the image to the registration roller pair 17 in the copying machine main body 1 in an inverted state. After being aligned by the pair of registration rollers 17, the document is again sent between the photosensitive drum 10 and the transfer charger 18, and an image of the second document is formed on the opposite surface. The paper P, on which images have been transferred on both sides in this manner, is discharged to the paper discharge tray 34 via the conveyance belt 20°, the fixing roller 21, the delivery roller 22, the switching gate 32, and the delivery roller pair 33.

As described above, the paper P conveyed along the conveyance path 35
are the first and second curved portions 35a.

Since the sheets P are bent in opposite directions at 35b, the curls on the sheets P are corrected and accumulated at 4 degrees inside the storage section. Therefore, the paper P taken out from the storage section 4o is conveyed without curling, and is smoothly conveyed without getting jammed in the conveyance system.

In the above embodiment, a case has been described in which a transport unit that enables only double-sided copying is used, but the present invention is not limited to this. For example, it is possible to perform double-sided copying and multiple copies on one side of a document. It is also possible to apply the present invention to a transport unit that carries

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As explained above, according to the present invention, since the direction of the transfer material being conveyed along the conveyance path is changed in opposite directions to each other by the first and second direction changing sections, the transfer material can be transferred in opposite directions. Curls on the transfer material can be corrected, and the transfer material can be smoothly transported without clogging the transport system.

FIG. 2 is a schematic configuration diagram showing a conventional example.

DESCRIPTION OF SYMBOLS 10... Photoreceptor drum (image forming part), 35... Conveyance path, 35a... First direction change part, 35b... Second direction change part, 40... Accommodation part (concentration part) Department).

Applicant's agent: Patent attorney Takehiko Suzue

Claims (1)

[Claims] After the image is transferred to the transfer material in the image forming section, the transfer material is accumulated in the accumulation section via the conveyance path, and the transfer material accumulated in this accumulation section is again conveyed to the image formation section. 1. An image forming apparatus for transferring an image, wherein the conveying path includes first and second direction changing sections that change the conveying direction of the transfer material to opposite directions.