JPH04129959A - Paper inverting device for picture forming device - Google Patents

Abstract

PURPOSE:To simplify a structure so as to promote a cost down by processing paper in a picture forming part, and guiding the paper to a paper refeed path in an inverting path, branched from a boundary part of a supply path, but providing an opening/closing part by an elastic part, turnably opening/closing the inverting path, in the boundary part. CONSTITUTION:In the case of performing both-side copying, paper is discharged by a discharge roller, and a detecting switch 27 is turned on to rotate a roller 31 in an inverting path 30 in the clockwise direction. A switching pawl 29 is placed in an attitude of full line, and a branch guide 34 is placed in a closing attitude by bringing an end part 34a of the guide 34 into contact with a recessed part 30a of the inverting path 30. Conveyed paper in a conveying roller 28 is advanced into the inverting path 30, while turning in the counterclockwise direction about the branch guide 34, and further conveyed to the downstream side. The detecting switch 27 is turned back off by passing of a rear end of the paper to reversely rotate the roller 31 after a predetermined time. The branch guide 34 is placed in the closing attitude when a rear end edge of the paper passes, and the paper is conveyed in a reverse direction in the inverting path 30. The conveyed paper is restricted by the closing attitude of the branch guide 34 and conveyed to a side of a paper refeed path 32 along an inverting guide surface 34c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a paper reversing device, particularly for an image forming apparatus for reversing paper processed in an image forming unit and refeeding the paper to the image forming unit. The present invention relates to a paper reversing device.

[Conventional technology]

2. Description of the Related Art For example, image forming apparatuses such as copying machines are already known that are equipped with a paper reversing device that inverts a sheet processed by an image forming section and refeeds the sheet to the image forming section.

This paper reversing device includes a reversing path having rollers that can be rotated forward and backward, a supply path that supplies paper processed by the image forming section to the reversing path, and a reversing path that refeeds the paper from the reversing path to the image forming section. The paper reversing unit includes a paper reversing section having a paper feed path. The paper refeed path is provided so as to branch from the boundary between the supply path and the reversing section. Further, a rotatable branch guide for opening and closing the reversing path is provided at the boundary portion. This branch guide is driven to open and close by a drive mechanism such as a solenoid or a cam mechanism.

When reversing the paper, first, the branch guide is brought into an open position by a drive mechanism such as a solenoid. Thereby, the paper processed by the image forming section is conveyed through the supply path into the reversing path of the paper reversing section. Next, the branch guide is brought into a closed position by the drive mechanism.

As a result, the paper that has been reversed on the reversing path is conveyed to the image forming section again through the refeeding path.

[Problem to be solved by the invention]

As described above, the conventional paper reversing device has a drive mechanism such as a solenoid or a cam mechanism as a drive mechanism for the branch guide. Therefore, the structure of the entire device becomes complicated and the cost also increases.

An object of the present invention is to provide a paper reversing device for an image forming apparatus that has a simple structure and can reduce costs.

[Means for Solving the Problems] A paper reversing device according to the present invention is a paper reversing device for an image forming apparatus for reversing a sheet processed by an image forming section and refeeding the paper to the image forming section. , a paper reversing section, an opening/closing section, and an elastic section.

The paper reversing section includes a reversing path for reversing the front and back of the paper;
The image forming apparatus includes a supply path that supplies paper processed by the image forming section to the reversing path, and a refeeding path that branches from a boundary between the supply path and the reversing path and receives the paper from the reversing path. are doing. The opening/closing portion is rotatably provided at the boundary portion and is for opening and closing the reversing path. The elastic portion allows the opening/closing portion to be in an open position when paper from the supply path comes into contact with the opening/closing part, and maintains a closed position in order to guide the paper to the re-feeding path when paper from the reversing path comes into contact with the opening/closing part. The opening/closing part is elastically biased toward the normally closed position so as to maintain the opening/closing part.

[Effect]

In the paper reversing device for an image forming apparatus according to the present invention, the paper processed by the image forming section is supplied to the reversing path by the supply path of the paper reversing section. At this time, the sheet comes into contact with the opening/closing part which is normally biased into the closed position by the elastic part, but the opening/closing part is allowed to take the open position by the elastic part. Thereby, the paper from the supply path is carried into the reversing path.

Next, when the paper from the reversing path comes into contact with the opening/closing section,
The opening/closing part is maintained in the closed position by the elastic part. As a result, the paper from the reversing path is guided to the refeed path rather than the supply path.

In this case, the opening/closing section is opened and closed by the elastic section.

Therefore, there is no need to provide a complicated drive mechanism for driving the opening/closing part, the structure of the device can be simplified, and the cost of the device can be reduced.

〔Example〕

FIG. 1 shows a copying machine employing an embodiment of the present invention.

In FIG. 1, a document table 2 is fixed to the upper surface of a copying machine main body 1, and a document holder 3 is attached to the upper part of the document table 2 so as to be openable and closable. On the right side of the copying machine body 1,
Paper feed force cellars I-4, 5, and 6 are removably attached. On the left side of the main body 1 of the copying machine, a paper ejection I-ray 7 is installed for ejecting copied paper.

Inside the copying machine main body 1, an exposure device 8 for reading a document is provided on the upper side thereof.

This exposure device 8 is composed of a light source, a mirror, and the like. Further, a photosensitive drum 9 on which an electrostatic latent image is formed is arranged in the center of the copying machine main body 1. Photosensitive drum 9
Around the charging device 10, the developing device 11, the transfer device 1
2, a paper separation device 13, and a cleaning device 14 are arranged. A paper feed conveyance path 15 for feeding paper is provided between the paper feed cassettes 4, 5.6 and an image forming section constituted by the photosensitive drum 9 and the like. Also, between the image forming section and the paper ejection tray 7, there is provided, in order from the image forming section side, a paper ejection transport path 16, a fixing device 17, and a printing device 1.
B and a punching device 19 are arranged. Further, below the fixing device 17, a reversing device 20 for reversing the front and back of the paper is provided. On the right side of the reversing device 20 in FIG. 1, there is provided an intermediate tray 22 for temporarily storing sheets reversed by the reversing device 20.

In FIG. 2, a detection switch 27 and a conveyance roller 2
8 is provided. Detection switch 27, fixing device 1
This is for detecting the presence of paper ejected from 7. This detection switch 27 is in the ON state (the state indicated by the chain double-dashed line) while the paper is passing through, and is OFF at other times.
state (solid line state). A switching pawl 29 is provided on the paper conveyance path 26 behind the conveyance roller 28 .

The switching claw 29 can take a discharge state (state shown by a chain double-dashed line) in which the paper is guided toward the discharge roller 21 side, and a reversal supply state (state shown by the solid line) in which it guides the paper toward the reversing device 20 side.

The reversing device 20 has a reversing path 30 for reversing the front and back sides of the paper. The reversing path 30 is provided continuously with the paper transport path 26. The reversing path 30 is provided with a reversing roller 31 capable of forward and reverse rotation. A paper refeeding path 32 branches off from the boundary between the reversing path 30 and the paper transport path 26 . The paper refeed path 32 is provided with a feed roller 33 for conveying the paper toward the intermediate tray 22 (FIG. 1).

A branch guide 34 is provided at the boundary between the reversing path 30 and the paper transport path 26.

This branch guide 34 is a generally triangular member when viewed in the direction of FIG. 2, and is rotatable at one end around a rod 35 extending in a direction perpendicular to the plane of the paper in FIG.

The branch guide 34 is provided with a conveyance guide surface 34b on the upper side and a reversal guide surface 34c on the lower side with the tip end 34a thereof in between. Further, a bar 36 is fixed to the base of the branch guide 34 on the rod 35 side. One end of a spring 37 (elastic member) is locked to the other end of the bar 36. The other end of the spring 37 is locked to a part of the wall surface of the paper refeed path 32. Due to the tensile force of the spring 37, the branch guide 34 is constantly urged in the clockwise direction in FIG. In addition, a recess 3 is provided in a part of the reversing path 30.
Da is formed. Tip portion 34a of branch guide 34
can enter into this recess 30a and come into contact with it. Furthermore, the clockwise rotation of the branch guide 34 is restricted by the end portion 34a coming into contact with the recess 30a. Note that the spring force of the kettle pull 37 causes the branch guide 34 to rotate counterclockwise and prevent the paper from passing when the leading edge of the paper transported by the transport roller 38 comes into contact with the transport guide surface 34b of the branch guide 34. Adjusted to an acceptable level.

On the other hand, a printing device 18 and a punching device 19 are provided on a path where the paper is guided from the conveyance roller 28 to the discharge roller 21. The printing device 18 is used to further print predetermined additional information at a predetermined position on the paper onto which the image has been fixed by the fixing device 17. The printing device 18 mainly includes:
A casing 40, an ink ribbon cassette 41 detachably held in the casing 40, and a thermal head 42.
It is composed of. Further, the punching mechanism 19 mainly includes a punch 45 that is supported so as to be movable up and down, and a paper guide plate 46 having a die hole 47 provided opposite to the punch 45. Below the die 47 is a punch 4.
A collection bowl 48 for collecting scraps extracted from the paper by the paper 5 and the die 47 is disposed.

Next, the operation of the above-mentioned copying machine will be explained.

Note that here, a case where double-sided copying is performed will be taken as an example. Since single-sided copying is common, its explanation will be omitted.

The paper that has been subjected to predetermined image forming processing by the image forming section is fixed by the fixing device 17, and then delivered to the ejection roller 25.
from there to the reversing device 20 side.

Here, the switching pawl 29 is set in the position shown by the solid line in FIG. Also, at this time, the paper pushes down the detection switch 27 to be in the ON state (double-dashed line state). Upon receiving the ON signal from the detection switch 27, the roller 31 of the reversing path 30 is driven to rotate forward (in the direction of the arrow). At this time, the end portion 34a of the branch guide 34 comes into contact with the recess 30a of the reversing path 30 due to the spring force of the spring 37, and the branch guide 34 is placed in the closed position.

The paper conveyed from the conveyance roller 28 enters the reversing path 30 while rotating the branch guide 34 counterclockwise in FIG. 2 against the spring force of the spring 37. The paper carried into the reversing path 30 is further conveyed to the downstream side within the reversing path 30 by the normal rotation of the rollers 31.

On the other hand, when the trailing edge of the paper passes through the detection switch 27 while the paper is being transported from the paper transport path 26 to the reversing path 30, the detection switch 27 returns to the solid line position (FIG. 2).
Becomes FF. After a predetermined period of time has elapsed from the OFF timing of the detection switch 27, the roller 31 in the reversing path 30 stops and starts rotating in reverse. Note that this predetermined time is sufficient time for the trailing edge of the sheet being conveyed to pass through the branching guide 34.

When the trailing edge of the sheet passes through the branching guide 34 and is carried into the reversing path 30, the spring force of the spring 37 causes the branching guide 34 to rotate clockwise in FIG. 2 and assume a closed position. Subsequently, as the rollers 31 reverse, the sheet in the reversing path 30 is conveyed in the opposite direction. During this conveyance, the leading end of the conveyed paper contacts the branch guide 34, but the closed position of the branch guide 34 is maintained because the end 34a of the branch guide 34 contacts the recess 30a.

As a result, the paper from the reversing path 30 is transferred to the re-feeding path 3 along the reversing guide surface 34c of the branch guide 34.
It is transported to the second side. Then, the paper is transferred to the feed roller 3
3 and is stored in the intermediate tray 22 (FIG. 1).

The paper in the intermediate tray 22 is taken out and conveyed to the image forming section again, where image formation and fixing processing are performed. At this time, the switching claw 29 is switched to the paper ejecting state (the state indicated by the two-dot chain line in FIG. 2), so that after the fixing process, the paper is transferred to the transport roller 2.
8 to the printing device 18 side. Then, if necessary, the thermal head 42 performs a printing process on a predetermined position on the paper. Furthermore, punch holes are formed at the edges of the paper by driving the punching device 19 as needed. Then, the paper is discharged to the paper discharge tray 7 via the discharge roller 21.

〔Effect of the invention〕

In the paper reversing device for an image forming apparatus according to the present invention, the opening/closing section is opened and closed by the elastic section as described above. Therefore, a complicated drive mechanism for driving the opening/closing part is not required, thereby simplifying the structure of the device and reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a copying machine employing an embodiment of the present invention, and FIG. 2 is an enlarged partial view of FIG. 1. 20... Reversing device, 26... Supply path, 3o... Reversing path, 32... Re-feeding path, 34... Branching guide, 3
7...Spring. Patent applicant Yukio Ono, agent of Mita Kogyo Co., Ltd., patent attorney

Claims (1)

[Claims] (1) A paper reversing device for an image forming apparatus for reversing a sheet processed by an image forming section and refeeding the sheet to the image forming section, the sheet reversing device comprising: a reversing path for reversing the front and back of the sheet; and the image forming section. a paper re-feeding path that branches from a boundary between the supply path and the reversing path and receives the paper from the reversing path; an opening/closing part rotatably provided in the boundary portion for opening and closing the reversing path; an opening/closing part that allows the opening/closing part to be in an open position when paper from the supply path comes into contact with the opening/closing part; an elastic part that always elastically biases the opening/closing part toward a closed position so as to maintain a closed position in order to guide the paper to the re-feeding path when paper from the reversing path comes into contact with the sheet; Paper reversing device for forming equipment.