JPH01269949A - Transfer paper conveying device - Google Patents

Abstract

PURPOSE:To reduce the actual occupation area and to obtain superior conveyance performance by arranging the insertion side and discharge side for transfer paper on the same side. CONSTITUTION:A conveyance path for discharged transfer paper extends from a paper feed part to a conveyance-direction inversion part 14 through a conveyor roller couple 7 in the opposite direction from insertion and the transfer paper is sent out of a paper feed cassette 11 as shown by an arrow A. Then the paper enters the conveyance-direction inversion part 14, where the paper is switched back so that the rear end becomes the front end and ejected to a paper discharge tray 13 along a switched conveyance path switching guide plate 9 through a registration roller 5, a transfer part 2, and a fixing device 3 as shown by an arrow B. Thus, the paper feed side and discharge side are arranged on the same flank. Consequently, the occupation space is reduced and the transfer paper never makes a U turn in the machine, so the conveyance performance for the transfer paper is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a transfer paper conveying device for an electrophotographic copying apparatus.

PRIOR ART Although many office automation (OA) devices do not require a space on either side when operated from the front, electrophotographic copiers typically require a space on one side of the machine body when operated from the front. The paper feed cassette protrudes from one side of the device, requiring additional space to install and remove it, and the copy tray protrudes from the other side, which requires space, so the actual occupied area is smaller than the main body of the device. There is a problem in that the size is considerably larger than that of .

For the purpose of improving this, as a conventionally proposed means, as shown in FIG. In some cases, paper is fed to a transfer section along the body 12, then immediately turned around and ejected to a paper output tray 16 provided at the top on the same side as the paper feed cassette, or as shown in FIG. A cassette 11 is provided at the lower part of the main body 10 of the apparatus, and paper is replenished from the front, and the paper fed from the - side edge is made a U-turn near the side edge of the apparatus and fed to the transfer section, where it is transferred and transferred. After fixing, there is an apparatus in which the paper is ejected to a paper ejection tray 16 provided on one side of the apparatus main body.

However, in the former method, since the transfer paper is U-turned deep inside the device, when a jam occurs, it is difficult to remove it. Furthermore, it is virtually impossible to copy onto cardboard or the like, and there are difficulties in transporting it.

In the latter case, since the U-turn part is located on the side of the main body, it is possible to remove the jammed paper by installing a door 14 on the side of the main body housing and inserting your hand through there. requires space on the sides. When using thick paper as transfer paper, it is possible to do so by attaching a manual feed tray to the U-turn section, but this also causes an increase in space.

As described above, there has been no conventional device that achieves both space saving and transportability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a copying apparatus which eliminates the above-mentioned disadvantages of conventional copying apparatuses, occupies a small actual area, and has excellent transportability.

Configuration In order to achieve the above object, the copying apparatus of the present invention feeds the transfer paper sent out from the paper feed section to the transfer section via a pair of registration rollers, and after the toner image is transferred, passes through the fixing section and discharges it outside the machine. In a transfer paper conveyance device of an electrostatic recording device, the direction in which the transfer paper is sent out from the paper feed section and the direction in which the transfer paper is inserted into the pair of registration rollers are generally opposite directions, and the transfer paper conveyance path from the paper feed section is as follows. It is inserted into the opposite side of the registration roller of a pair of transport rollers that are provided upstream of the pair of registration rollers and is reversible in the forward and reverse directions. ] - A path converting member that can be switched to a path to a pair of rollers, and a sheet detecting means located between the path converting member and the pair of conveying rollers, and the sheet detecting means is located between the pair of conveying rollers and the pair of registration rollers, and the sheet detecting means is located between the pair of conveying rollers and the pair of registration rollers. It has a transfer paper conveyance direction reversing section on the side, and after being sent out from the paper feeding section and fed into the transfer paper conveyance direction reversing section by the pair of conveyance rollers until its rear end is sandwiched between the pair of conveyance rollers, The present invention is characterized in that the path switching member is switched to the registration roller side, and the transfer roller pair is reversed to switch the transfer paper back toward the registration roller.

In the transfer paper conveyance device with this configuration, when performing continuous copying, the leading paper of successive sheets comes out of the transfer paper conveyance direction reversing unit and faces the registration roller, and the trailing edge passes through the meeting point from the paper feed unit. Since the succeeding paper cannot be inserted into the pair of conveying rollers until after the copying process has been completed, there is a drawback that the copying speed decreases to some extent.

This difficulty can be solved in the above configuration by making the conveyance speed from the paper feed section to the pair of forward and reverse reversible conveyance rollers faster than the conveyance speed at which the paper is fed from this conveyance roller pair to the transfer section via the registration rollers. be done.

Furthermore, the above-mentioned transport roller pair has a driving roller on the path side from the paper feeding section, and a torque limiter is interposed between this roller and its driving means, and the limit torque is transferred between the roller pair to the registration roller side. When the transfer paper conveyed from the paper feed section is sandwiched between the transfer paper and the transfer paper conveyed from the paper feed section, the torque is set to be greater than the torque due to the frictional force between the two transfer papers, and smaller than the torque due to the frictional force between the transfer paper and the roller surface. By doing so, it becomes possible to further reduce the interval between consecutively fed sheets.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing an example of a copying machine equipped with a transfer paper conveying device according to the present invention.

Inside the copying machine 10, an electrophotographic image forming means 1 is provided. Although its structure is omitted in the figure, it consists of process means for carrying out a known electrostatic photographic process, such as a photoreceptor, original exposure means, developing means, and transfer means, and the toner formed on the photoreceptor. A transfer section 2 having a transfer charger for transferring an image onto a transfer paper is provided along the photoreceptor.

A paper feed cassette 11 for feeding transfer paper to the transfer unit 2 is provided at the lower right side of the inside of the casing of the copying machine 10 so that a portion of it protrudes outside the casing. A paper feed roller 11m is provided so as to be in contact with the east upper surface of the paper placed in the paper cassette. The paper in the paper feed cassette 11 is fed in the direction shown by arrow A by a paper feed roller 11a. A pair of separation rollers 6 is provided on the downstream side of the paper feed roller 11a, and the paper passes through a pair of transport rollers 7 that can be rotated in forward and reverse directions, and then reaches the transport direction reversing section 1-4. A paper detection switch 8 is provided immediately on the right side of the transport roller pair 7. A transport path extending from the paper feed cassette 11 to the transport roller pair 7 serves as a rotational fulcrum immediately to the right of the paper detection switch 8;
From the conveyance roller pair 7 to the transfer section 2 via the registration roller pair 5
, a conveyance path switching guide plate 9 for changing the sheet conveyance path is provided on the conveyance path leading to the paper discharge tray 13 via the fixing device 3.

The conveyance path of the transfer sheet from the conveyance direction reversing section 14 to the conveyance roller pair 7, through the registration roller 5, the transfer section 2, and the fixing device 3, and then discharged to the paper discharge tray as shown by arrow B, is from left to right as shown in the figure. X - Extends in a straight line, and is opposite to the direction in which it is inserted from the paper feed section to the conveyance direction reversing section 14 via the conveyance roller pair 7. Therefore, the transfer paper is stored in paper feed cassette 1.
1 in the direction of arrow A, and the transport direction reversing unit 14
At that point, switch back to make the first rear end the front end, and pass through the registration rollers 5, the transfer section 2, and the fixing device 3 along the switched conveyance path switching guide plate to the paper output tray 15 in the direction of arrow B. is discharged.

The transfer paper conveyance operation will be explained step by step with reference to FIG.

(&) After passing through the separation row 26 from the paper feed cassette, the sheet is inserted into a pair of transport rollers 7 rotating in the direction of the arrow along the guide plate 9 located on the paper feed path side, and then transported to the transport direction reversing section 14.

(b) When the trailing edge of the transfer paper is detected by the paper detection sensor 8, the conveyance roller 27 stops rotating while holding the trailing edge of the transfer paper, and the conveyance path switching guide plate 9 is activated by a solenoid (not shown) or the like. It is displaced to a position where it guides the paper toward the registration rollers 5.

(c) Next, the transport roller pair 7 rotates in the reverse direction, and the transfer paper is fed until its rear end hits the registration roller pair 5, which has been stopped first, and a buckling is formed.

(d) The registration rollers 5 are rotated at the same timing so that the toner image on the photoreceptor of the image forming section 1 and the leading edge are aligned, and the transfer paper is sent out from the transfer paper conveyance direction reversing section and sent to the transfer section 2. .

(e) When the transfer paper is sent out from the registration rollers 5, the path switching guide plate 9 is displaced to the paper feeding side.

Cf) During continuous copying, the next transfer sheet is inserted into the conveyance roller pair 7 after the trailing edge of the previous transfer sheet passes the detection sensor 8 and the rotation direction of the conveyance roller pair 70 is changed.
) and the same process is repeated.

According to the transfer paper conveying device described above, the paper feed side and the discharge side can be on the same side, so the space occupied is reduced, and the transfer paper does not make a U-turn inside the machine, so
The conveyance of the transfer paper is good, and it is also possible to copy thick paper, which could not be conveyed using a conveyance path with a U-turn section. Furthermore, during continuous copying, the next transfer paper is fed by detecting the trailing edge of the previous paper, so the drop in copying speed, which was a drawback of the switchback method, is considerably improved.

However, it is not possible to convey the transfer paper continuously at close intervals as in the U-turn method.

As a measure to improve this point, as shown in FIG. 6, in the process of feeding the transfer paper from the paper feeding section to the transfer direction conversion section by the conveyance roller pair 7, which is performed after the state shown in FIG. 2(f), By making the speed V1 larger than the circumferential speed v2 of the registration roller pair 5 after 70 revolutions of the conveying roller pair, it becomes possible to narrow the gap between the trailing edge of the preceding paper and the leading edge of the succeeding paper, which eliminates the drawback of the switchback method for copying. The slow speed is greatly improved.

As a measure to further reduce the transfer paper interval during one continuous paper feeding, as shown in FIG. 4(e), the lower roller 7-
2 is a drive roller, and a torque limiter 7 is attached to the drive shaft 7-1.
-6, the sheet may be driven in a counterclockwise direction (in the direction of conveyance from the sheet feeding section to the conveying direction reversing section) in such a manner that torque exceeding a certain level is not applied. The magnitude of the limit torque at this time is set to be larger than the torque due to the frictional force between the transfer sheets and smaller than the torque due to the frictional force between the transfer sheet and the roller.

The transfer sheet conveyance operation in this case will be explained in detail with reference to FIG.

The processes from (,) to (d) are similar to the first embodiment described in FIG.

In the process (e), the drive shaft 7-1 rotates counterclockwise. Since the front end of the transfer paper is already held between the pair of registration rollers 5 and conveyed at the circumferential speed, even if the drive shaft 7-1 is rotated counterclockwise, the torque due to the frictional force between the rollers and the transfer paper is is larger than the limit torque, the roller case rotates clockwise as the transfer paper is conveyed toward the registration roller pair 5.

In the process of (f), the drive shaft 7-1 rotates counterclockwise, and since the torque of the torque limiter 7-3 is greater than the torque between the transfer sheets, the drive shaft 7-1 is pulled by the registration roller and the transport roller pair 7 is rotated. When the next transfer paper is inserted from the paper feed unit in the opposite direction to the transfer paper that is passing between them, the upper transfer paper and the lower transfer paper will slip, and the upper and lower rollers, respectively, will slip. Conveyed at circumferential speed.

As a result, before the leading paper passes through the pair of conveying rollers 7, the following paper is inserted into the pair of conveying rollers 7 and conveyed in opposite directions, making it possible to reduce the gap between the two to the necessary limit, using a switchback method. The problem is completely resolved.

Effects As described above, according to the present invention, it is possible to measure the reduction in occupied space by setting the transfer paper insertion side and paper ejection side on the same side.
Moreover, since a U-turn portion can be eliminated in the transfer paper conveyance path, the conveyance of the transfer paper is increased. Further, it is possible to eliminate the reduction in transfer speed caused by the switchback method.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of a copying machine having a transfer paper conveyance device of the present invention, FIG. 2 is an explanatory view explaining the transfer paper conveyance function, and FIG. FIG. 4 is an explanatory diagram to explain the structure and operation of another embodiment, and FIGS. 5 and 6 are explanatory diagrams to explain the problems of the conventional transfer paper conveying device. 1... Electrophotographic image forming means 2... Transfer section 6... Fixing section 5... Registration roller pair 6...
Separation roller pair 7... Forward/reversible transport roller pair 7-1... Drive shaft 7-2... Roller part 7-
6...Torque limiter 8...Paper detection means 9...Conveyance path switching guide plate 10...Device main body 11...Paper feed cassette 1
6... Paper ejection tray 14... Conveyance direction reversal unit (1 person outside) , ＼ ＼, ノ

Claims (3)

[Claims] (1) In a transfer paper conveyance device of an electrostatic recording device, which feeds the transfer paper sent out from the paper feed unit to the transfer unit via a pair of registration rollers, and discharges it outside the machine via the fixing unit after the toner image is transferred, The direction in which the transfer paper is sent out from the paper section and the direction in which the transfer paper is inserted into the pair of registration rollers are generally opposite directions, and the transfer paper conveyance path from the paper feed section is a forward and reverse direction provided upstream of the pair of registration rollers. A path converter is inserted on the side opposite to the registration rollers of the possible transport roller pair, and the transfer paper transport path can be switched between the path from the paper feed section and the path to the registration roller pair. parts and
a sheet detecting means located between the path converting member and the pair of conveying rollers; a transfer paper conveying direction reversing section on the opposite side of the pair of registration rollers of the pair of conveying rollers; After being sent out and fed into the conveying direction reversing section by the pair of conveying rollers until the rear end portion is sandwiched between the pair of conveying rollers, the path switching member is switched to the registration roller side, and the pair of conveying rollers is reversed. A transfer paper conveying device characterized in that the transfer paper is switched back toward the registration rollers. (2) The speed at which the transfer paper is transported from the paper feed section to the pair of transport rollers that can be rotated forward and backward is faster than the speed at which the paper is fed from the pair of transport rollers to the transfer section via the registration rollers. The transfer paper conveyance device according to claim 1. (3) The above transport roller pair has a driving roller on the path side from the paper feed section, and a torque limiter is interposed between this roller and its driving means, and the limit torque is transferred between the roller pair to the registration roller side. When the transfer paper conveyed from the paper feed section is sandwiched between the transfer paper and the transfer paper conveyed from the paper feed section, the torque is set to be greater than the torque due to the frictional force between the two transfer papers, and smaller than the torque due to the frictional force between the transfer paper and the roller surface. The transfer paper conveying device according to claim 1, characterized in that: