JPS63235250A - Device for changing paper sheet transfer direction - Google Patents

Abstract

PURPOSE:To make it possible to transfer a paper sheet from a transfer roller to a transfer direction changing roller securely and transfer the paper sheet to an intermediate tray easily by constituting a paper sheet transfer direction changing device with the paper sheet transfer direction changing roller and a curl forming member. CONSTITUTION:A paper sheet transfer direction changing device is constituted with a paper sheet transfer direction changing roller 27 for changing the transfer direction of a paper sheet 9a transferred to the reversal guide section 24 and for transferring the paper sheet, and a curl forming member 25 for forming a curl at the rear end 9b of the paper sheet to be transferred to the reversal guide section 24. With this constitution, the rear end 9b of the paper sheet is curled upward by a curl forming member 25 when the paper sheet 9a butts against a front end butting wall 24b of the reversal guide section 24 and the rear edge 9b' of the paper sheet butts against the surface of a transfer roller 21a. As a result, the paper sheet 9a can be securely transferred by means of the transfer direction changing roller 27 to an intermediate tray 31 as the paper sheet is transferred along the surface of the transfer roller 21a toward the transfer direction changing roller 27.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper conveyance direction converting device used when recording on both sides of a paper in an image forming apparatus such as a copying machine or a printer.

[Conventional technology]

Generally, when performing double-sided printing in which images are recorded on both sides of paper in an image forming apparatus such as a copying machine or printer, the image forming apparatus itself records on one side of the paper that is fed one sheet at a time from the paper feed tray. After that, in order to perform recording on the back side as well, the direction of conveyance of the sheet on which one side has been recorded is changed, and the one-sided recording sheet is again conveyed to the transfer section.

Conventionally, such a paper conveyance direction changing device is disclosed in, for example, Japanese Patent Application Laid-open No. 52-149128, as shown in FIGS.
A configuration as shown in is disclosed. That is,
The three bearings pressed against each other are rollers 51, 52, 53.
, a paper path changing device 54, and an intermediate hopper 55 that receives one sheet of paper at a time. During double-sided recording, the paper path changing device 54 is positioned as shown in FIG. , the single-sided recorded paper is transported via the transport rollers 56 and is transported between rollers 51 and 52 and temporarily stored in the intermediate hopper 55 .

Next, the paper path changing device 54 is switched as shown in FIG.
7, the paper is conveyed again toward the transfer section for recording on the back side. When the paper with the reverse side recorded is transported by the transport roller 56, the paper path changing device 54 is switched as shown in FIG. It has become so.

As described above, the device disclosed in the above-mentioned publication has a drawback in that in order to change the conveying direction of the paper, the paper path changing device must be switched each time the direction of conveyance of the paper is changed.

As a device that overcomes these drawbacks, a configuration as shown in FIG. 6 is known. In the figure, 101a
, b, 102a, and b are a pair of conveyance rollers that convey the paper 103 recorded in the main body of the image forming apparatus (not shown), and 104 is a pair of conveyance rollers 101a, b, and 1.
A switching gate plate placed between 02a and 02b is used to switch between single-sided and double-sided recording modes. Reference numeral 105 denotes a reversing guide section for reversing the conveying direction of the paper 103 in the double-sided recording mode, and the distance between the tip end abutment wall 105a of the reversing guide section 105 and the nip section 106 of the conveying rollers 101a and 101b is It is configured to be shorter than the length of the paper 103. Reference numeral 107 denotes a pressing sheet for pressing the rear end of the paper 103, and a reversing guide section 105
One end of it is attached to. 108 is a conveyance roller 101a disposed immediately in front of the gate plate 104;
A conveyance roller 101 on the lower side of b is a paper conveyance direction changing roller provided so as to be in pressure contact with b, and 109 is an intermediate tray for double-sided recording. Note that 110, 111, and 112 are paper guides.

In the sheet conveyance direction changing device having such a configuration, in the double-sided recording mode, the switching gate plate 104 is switched downward, and the sheet 103 recorded on one side is reversely guided through the conveyance rollers 101a, b and the gate plate 104. When the leading edge of the single-sided recording paper 103 hits the leading end abutment wall 105a of the 0 reversing guide part 105 that is being conveyed toward the section 105, the rear end 103a of the sheet 103 curls as shown in the figure, and is conveyed to the lower part. The roller 101 b transports the paper toward the pressure contact portion with the transport direction conversion roller 108 . Next, the lower conveyance roller 101b and the conveyance direction conversion roller 10
8, the conveyance direction of the paper 103 is changed and the paper 103 is conveyed toward the intermediate tray 109. That is, the configuration is such that sheets of single-sided recording can be sequentially reversed and conveyed to the intermediate tray 109 while the switching gate plate 104 is being switched.

[Problem that the invention seeks to solve]

However, in the paper conveyance direction changing device configured as shown in FIG. As shown by the dotted line in the figure, the paper may be curved in an S-shape. When the paper is curved in this way, the trailing edge of the paper does not touch the surface of the lower conveyance roller 101b, and the trailing edge does not touch the surface of the conveyance roller 101b. It is placed on surface b and slides on the surface of the conveyance roller 101b,
It is in a state where it is not transported along with the transport roller 101b. Therefore, in this case, the trailing edge 103a of the paper is used for
There is a problem in that the sheet 103 is not transferred to the feeding direction conversion roller 108, making it impossible to convey the sheet 103 to the intermediate tray 109.

The present invention was made in order to solve the above-mentioned problems in conventional paper conveyance direction converting devices, and the present invention reliably transfers the trailing edge of the paper from the conveyance roller to the conveyance direction conversion roller.
It is an object of the present invention to provide a paper conveyance direction changing device that allows paper to be easily conveyed to an intermediate tray.

[Means and operations for solving the problems] In order to solve the above problems, the present invention provides a conveyance roller that conveys recording paper, and a single-sided or double-sided recording mode of the recording paper conveyed by the conveyance roller. a switching gate plate that is switched according to the switching operation; and a reversing guide section for reversing the conveying direction of the sheet conveyed through the switching gate plate in the double-sided recording mode, the leading end abutment wall portion and the conveying direction of the sheet being reversed. One roller is arranged so that the distance between the nip portions of the rollers is shorter than the length of the paper, and the other is a paper conveyance direction conversion roller for converting the conveyance direction of the paper conveyed into the reversing guide section and conveying it. , a curl forming member for forming a curl on the trailing edge of the sheet conveyed to the reversing guide, the member being arranged to protrude from a straight line connecting the entrance of the reversing guide and the nip portion of the conveying roller; These components constitute a paper conveyance direction changing device.

With this configuration, when the paper hits the tip end abutment wall of the reversing guide, the trailing edge of the paper is curled upward by the pull forming member, so that the trailing edge of the paper is pushed against the conveying roller. The paper is surely brought into contact with the surface, and is therefore conveyed along the surface of the conveyance roller toward the conveyance direction conversion roller, and the sheet is surely conveyed to the intermediate tray by the conversion roller.

〔Example〕

Examples will be described below. FIG. 1 is a schematic diagram showing the overall configuration of an image forming apparatus using an embodiment of the paper conveyance direction changing device according to the present invention, and this configuration example is configured as a printer using an ion flow type recording head. It shows what was done.

2, l is a dielectric drum, 2 is the dielectric drum l
a recording head for forming an electrostatic charge image by emitting a modulated ion flow in a dot shape in accordance with the image signal to be recorded; 3 for developing the electrostatic charge image on the dielectric drum l with toner; A developing device 4 is a transfer roller for transferring the toner image on the drum 1 onto a sheet of paper, and is in pressure contact with the dielectric drum 1 and driven. Reference numeral 5 denotes an elevator paper feeding unit disposed below the main body 6 of the apparatus, and 7.8 separates and feeds the sheets 9 stacked and stored in the elevator paper feeding unit 5 toward the transfer section. 10 is a normal paper feed tray placed on the side of the main body 6 of the apparatus; 11.12 is a paper feed roller and retard for separating and feeding the paper from the paper feed tray IO; , 13
．． 14.15.16.17.18 are paper guides, 19.
20, 21, and 22 are a pair of conveyance rollers, respectively.

Reference numeral 23 denotes a switching gate plate disposed between the transport rollers 21 and 22, which is operated to switch depending on the single-sided or double-sided recording mode.In the single-sided recording mode, the paper is transferred to the transport roller via the paper guide 18. Transported towards 22,
During double-sided recording, the paper is conveyed toward a reversal guide section 24, which will be described next. Reference numeral 24 denotes a reversing guide section for reversing the sheet in the double-sided recording mode; 25 denotes a curl forming member for curling the trailing edge of the sheet carried into the reversing guide section 24 into an upward mountain shape; As shown in the enlarged partial view of the figure, the nip portion 21 of the conveyance roller 21
It is formed on the temporary gate 23 so as to protrude from the straight line l connecting the entrance 24a of the reversing guide section 240 and the entrance 24a of the reversing guide section 240.

Reference numeral 26 denotes a pressing sheet made of mylar or the like for pressing the curled portion of the rear end of the paper, one end of which is fixed to the entrance 24a of the reversing guide section 24, and the other end of which extends to the vicinity of the transport roller 21 and hangs down under its own weight. It is located in 2
7 is attached to a support shaft 29 arranged to intersect at a slight angle (approximately 1 degree) with the support shaft 28 of the lower transport roller 21a of the transport roller 21 in front of the gate plate 23, and A paper conveyance direction conversion roller 21a is in pressure contact with the lower surface of the apparatus main body 6 and the elevator paper feeding unit 5.
This is an intermediate tray for double-sided recording placed between the top surface of the Note that the distance between the nip portion 21' of the conveyance roller 21 and the tip end abutting wall portion 24b of the reversing guide portion 24 is set to be shorter than the length of the sheet. Further, the intermediate tray 31 includes a side edge regulating plate 32 and a leading edge regulating plate 33 for regulating and storing the side edges and leading edge of the paper to be carried in, a tiltable tray bottom plate 34, and each regulating plate 32° for regulating and storing the paper to be carried in. A diagonal roller 35 for conveying the paper toward
i, 3'6.

Next, the operation of an image forming apparatus using the sheet conveyance direction converting device configured as described above will be explained. First, a case will be described in which paper is fed from the elevator paper feeding unit 5 and double-sided recording is performed.

By manually inputting a double-sided recording mode signal, the switching gate plate 23 is switched downward as shown by the solid line in the enlarged views of FIGS. 1 and 2, and the transferred paper is conveyed to the reversing guide section 24. is set to

In this state, paper is fed from the elevator paper feed unit 5, but when the elevator m structure rises and a paper surface height sensor (not shown) turns on, the elevator rising operation stops. Thereafter, the elevator paper feed roller 7 rotates to separate the sheets 9 one by one and transport them toward the transfer section.

A toner image is transferred from the dielectric drum 1 to the paper 9 transported by the paper feed roller ruff in the transfer section, passes through transport rollers 20 and 21, and is further transported toward the reversing guide section 24 through the gate plate 23. Ru.

As shown in FIG.
When the leading edge of the paper 9a transferred to the paper 4b abuts against the paper 9a, the length of the paper 9a is longer than the distance between the leading edge abutting wall part 24b of the reversing guide part 24 and the nip part 21' of the conveying roller 21.
The rear end 9b of the paper 9a is reliably curled upward by a curl forming member 25 provided protruding from the gate plate 23, and the curled portion is pressed downward by a pressing sheet 26. As a result, the trailing edge 9b' of the paper 9a hits the surface of the lower conveyance roller 21a, and is transported along with the surface toward the contact portion with the paper conveyance direction conversion roller 27. The conveyance of the reversed sheet 9a toward the intermediate tray 31 is started by the direction changing roller 27.

At this time, the lower conveyance roller 21a and the paper conveyance direction converting roller 27 convey the paper 9a slightly outwardly and diagonally in a direction away from the side edge regulating plate 32 of the intermediate tray 31, and the paper 9a is conveyed to the pair of conveyance rollers 21a and 27. Even if there is a shift in the conveyance until reaching the intermediate tray 31, the paper 9a to be carried in is prevented from coming into contact with the entrance corner of the intermediate tray 31, etc.

When the reversed sheet 9a begins to be conveyed by the sheet conveyance direction conversion roller 27, it is detected by the sheet passage sensor 37, and the diagonal roller 35 in the intermediate tray 31 starts rotating after a certain period of time and continues to rotate for a certain period of time. The paper 9a conveyed by the paper conveyance direction conversion roller 27 and carried into the intermediate tray 31 is transferred to the intermediate tray 31.
is conveyed obliquely toward the side edge regulating plate 32 by a diagonal roller 35 on the bottom plate 34 in a direction opposite to the conveyance direction by the previous paper conveyance direction conversion roller 27,
One side edge of the paper 9a contacts the side edge regulating plate 32 and is regulated, while the leading edge of the paper 9a contacts the leading edge regulating plate 33 and is regulated and stored.

Thereafter, in the same manner, the sheets 9a having the toner images transferred to their surfaces are sequentially stacked and stored in the intermediate tray 31 in an orderly manner, with their side edges and leading ends being restricted by the side edge regulating plate 32 and the leading end regulating plate 33, respectively. Note that the paper 9 to this intermediate tray 31
When the paper 9a is stored, the trailing edge of the paper 9a is almost in contact with the paper trailing edge pressing plate 36 which is in the retracted position.

A set number of sheets of paper 9 are transferred to the intermediate tray 31.
a is stored, paper feeding from the elevator paper feeding unit 5 is stopped and paper ejection to the intermediate tray 31 is stopped, and the switching gate plate 23 is moved as shown by the dashed line in FIGS. 1 to 3. , then the elevator mechanism is raised and the bottom plate 3 of the intermediate tray 31 is raised on the upper surface of the paper 9.
4 to release the lock on the tray bottom plate 34, the elevator 411JR is lowered, and accordingly, the tray bottom plate 34 is rotated as shown in FIG. 4, and its tip is lowered.

In conjunction with this downward movement, the diagonal roller 35 moves the intermediate tray 3
At the same time, as shown in FIG. 4 (8), the loading storage paper 9a is
is pressed and moved toward the paper feed roller 7 by the paper trailing edge press Fi36.

Next, the elevator mechanism of the elevator paper feed unit 5 is raised again, and as shown in FIG. 7 to make pressure contact.

Then, the paper feed roller 7 is rotated to convey the paper sheets 9a in the intermediate tray 31 one by one again to the transfer section, transfer the toner image to the other untransferred surface, and transfer the paper 9a to the transfer roller 20.21.22. After passing through the guides 16, 17 and 18, the output paper storage tray 3
Discharge to 8.

When paper feeding from the intermediate tray 31 is completed, the elevator mechanism of the elevator paper feeding unit 5 rises, and the bottom plate 34 of the intermediate tray 31 is pushed up by the upper surface of the paper 9 stacked and stored in the elevator paper feeding unit 5. The bottom plate 34 of the intermediate tray 31 is raised again and locked, and is maintained in a state in which it receives the incoming paper. Further, in conjunction with this operation, the paper trailing edge pressing plate 36 is also held in the retreated position, and the skew roller 35 also comes into contact with the tray bottom plate 34, completing the double-sided copying operation.

As described above, in the above embodiment, the trailing edge 9b of the sheet 9a carried into the reversing guide section 24 is reliably curled upward by the curling member 25 formed in a protruding manner. Therefore, the trailing edge 9b' of the paper 9a comes into contact with the surface of the transport roller 21b, is transported along with the transport roller 21b, and is drawn into the paper transport direction changing roller 27. Thus, the conveying direction of the paper 9a can be easily changed.

The duplex recording operation by feeding paper from the elevator paper feed unit 5 has been described above, but the duplex recording operation is performed by feeding paper from a simple paper feed tray 1O that is not an elevator system and is placed on the side of the main body of the apparatus. In this case, the same operation steps are used.

In other words, when the paper feed roller 11 starts rotating, the paper feed tray 1
After the sheet is fed from 0 and the toner image is transferred at the transfer section, the conveying direction of the sheet is reversed at the reversing guide section 24,
The paper is transported in the opposite direction by the paper transport direction conversion roller 27 and temporarily stored in the intermediate tray 31 . The operation after the paper is stored in the intermediate tray 31 is driven and controlled by the operation of the elevator mechanism of the elevator paper feed unit 5, just as in the case of paper feeding from the elevator paper feed unit 5 described above. The transfer operation to the back side is performed, and the paper ejection tray 38
is discharged to.

Further, in the illustrated configuration example, by keeping the gate plate 23 switched upward, the transfer paper 9a
directly to the paper output tray 3 without discharging to the intermediate tray 31.
Of course, it is possible to perform a single-sided recording operation by discharging the paper onto the paper 8.

In the above embodiment, the reversing guide section is shown as being arranged horizontally, but even if it is arranged with a slight upward inclination, the conveying direction of the sheet can be changed reliably in the same way.

〔Effect of the invention〕

As described above based on the embodiments, according to the present invention, when a sheet of paper hits the tip end abutment wall of the reversing guide, the trailing edge of the sheet is curled upward by the curl forming member, and the curling member is curled upward. The trailing edge portion of the sheet is reliably transported by the transport roller toward the paper transport direction conversion roller, and the transport direction can be easily changed by the conversion roller for transport.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus to which an embodiment of a paper conveyance direction converting device according to the present invention is applied;
FIG. 2 is an enlarged view of the main part, FIG. 3 is a diagram showing the conversion operation mode of the paper conveyance direction, and FIG.
Figure 5 is a diagram showing how paper is fed from the intermediate tray.
(Bl, Figure 6 is a schematic diagram showing a conventional sheet conveyance direction changing device. In the figure, 9a is a sheet of paper, 9b is a trailing edge of the sheet, 21, 2
2 is a conveying roller, 23 is a gate plate, 24 is a sheet reversing guide, 25 is a curl forming member, 26 is a pressing plate, and 27 is a sheet conveying direction changing roller. Patent applicant: Olympus Optical Industry Co., Ltd. Figure 5 (A)

Claims (1)

[Claims] A transport roller that transports the paper, a switching gate plate that is switched depending on whether the paper transported by the transport roller is in single-sided or double-sided recording mode, and a switching gate plate that is operated to switch depending on whether the paper that is transported by the transport roller A reversing guide section for reversing the conveying direction, which is arranged so that the distance between the tip end abutting wall portion and the nip section of the conveying roller is shorter than the length of the paper, and an inside of the reversing guide section. a sheet conveyance direction conversion roller for converting the conveyance direction of the sheet conveyed to the sheet and conveying the sheet; and a sheet conveyance direction conversion roller arranged to protrude from a straight line connecting the entrance of the reversing guide section and the nip section of the conveyance roller. A paper conveyance direction changing device comprising: a curl forming member for forming a curl on a trailing edge of the paper conveyed to the reversing guide section.