JPH1179563A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve loading performance for sheets by restraining the loop amount of the sheet from being increased in an intermediate tray. SOLUTION: A sheet S discharged on an intermediate tray 29 is guided by a movable sheet guide 32 and conveyed by an auxiliary roller 31 until the sheet tip is brought in contact with a movable shutter 44. The auxiliary roller 31 waiting in the position shown in the figure in form of a solid line is lowered as shown in the figure in form of a dotted line after the sheet is discharged, and the sheet S is conveyed. When the sheet S is further conveyed by the auxiliary roller 31, a loop is formed between the auxiliary roller 31 and the movable shutter 44, a pressure receiving part 32a is pressed up by upward pressing force of the loop, a fulcrum part 32a to be brought in contact with the sheet S is taken as a fulcrum, and the auxiliary roller 31 is pushed up by leverage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and the like.

[0002]

2. Description of the Related Art Image forming apparatuses such as copiers, printers, and facsimile machines have a multiplex mode in which a single sheet (sheet material) is formed a plurality of times on the same surface, and a single-sheet front and back surface. Some apparatuses have a double-side mode for performing image formation.

[0003] Sheets on which images are formed in the multiplex mode and the duplex mode are placed on an intermediate tray (re-feeding sheet material stacking means) installed in the main body of the image forming apparatus after the first image formation. After being once stacked, the sheet is re-fed to the image forming section from the intermediate tray.
In this case, the sheet on which the first image formation has been performed in the multiplex mode is stacked on the intermediate tray with the image forming surface facing down, and the sheet on which the first image formation has been completed in the double-sided mode has the image formation surface. The sheet is stacked on the intermediate tray with the sheet facing upward.

FIG. 3 shows the overall structure of a conventional image forming apparatus (copier) having a multiplex mode and a duplex mode.

First, the configuration of the image forming apparatus shown in FIG. 3 will be described. Here, the overall configuration will be described along the flow of the sheet.

The image forming apparatus 100A includes a plurality of front loading type paper feed cassettes 1 to 4. Sheets S1 to S4 of different sizes are stacked and stored in each of the paper feed cassettes 1 to 4. For example, an A5 size or statement size sheet S1 is loaded and stored in the cassette 1, an A4 size or B5 size or letter size sheet S2 is loaded and stored in the cassette 2, and a cassette 3 is stored in the cassette 3. Sheets S3 of A4R size, B5R size, or letter R size are stacked and stored, and B4 size or legal size sheets S4 are stacked and stored in the cassette 4.

In the image forming apparatus 100A, the sheets S1 to S4 in the sheet cassettes 1 to 4 are selectively fed. The sheets S1 to S4 stacked and stored in the respective sheet cassettes 1 to 4 are sequentially fed from the top sheet by the sheet feeding roller 5 rotating counterclockwise in the drawing. The sheet S fed out by the paper feed roller 5 is separated only by the separation roller pair 6 from the uppermost sheet, and sent to the registration roller pair 13 in the rotation stopped state via the conveyance roller pairs 7 to 12.

The conveying roller pairs 7 to 11 convey the sheet S until the leading end of the sheet strikes the nip of the registration roller pair 13 to form a predetermined amount of loop. The skew state of the sheet S is corrected by the formation of the loop.

The sheet S whose skew has been corrected is a pair of registration rollers whose rotation is started at a timing when the position of the toner image on the photosensitive drum 14 rotating clockwise in FIG. By 13, it is sent to a transfer section as an image forming section between the photosensitive drum 14 and the transfer charger 15. While passing through the transfer section, the toner image on the photosensitive drum 14 is sequentially transferred to the sheet surface by the transfer charger 15.

The sheet S on which the transfer of the toner image has been completed is sent to the fixing roller pair 17 by the transport belt 16. Then, the toner is heated and pressed while passing through the nip of the fixing roller pair 17, so that the transfer toner image is fixed on the sheet surface.

The sheet S conveyed by the conveying roller pair 18 after the toner image fixing process is completed is sent to the paper discharging roller pair 20 through the paper discharging path 19 in the normal mode.
The paper is discharged onto a paper discharge tray 21 outside the apparatus by the paper discharge roller pair 20. In the normal mode, the flapper 22 opens the discharge path 19 and closes the vertical path 23 as shown by the solid line.

Further, the sheet S conveyed by the conveying roller pair 18 after the fixing process of the toner image is sent to the vertical path 23 leading to the intermediate tray 29 in the case of the multiplex mode and the duplex mode. In this case, the flapper 22 closes the discharge path 19 and opens the vertical path 23 as shown by the dotted line.

In the case of the multiplex mode, the sheet S sent to the vertical path 23 is transported by the conveying roller pairs 24 to 26 into the carry-in path 2.
7 and the intermediate tray 29 by the carry-in roller pair 28.
The intermediate tray 2 is sent to the upper discharge path 60 and the image forming surface faces downward from one of the discharge roller pairs 61 to 64 installed in the sheet conveying direction of the discharge path 60.
9 is discharged.

When a sheet S having the maximum size in the transport direction is used, the first flapper 66 rotates upward and discharges the sheet S from the discharge port 41. When the next largest sheet S is used, the second flapper 67 rotates upward and discharges the sheet S from the first discharge roller pair 61. When the next largest sheet S is used, the third flapper 68 is used.
Rotates upward to discharge the sheet S from the second discharge roller pair 62. When the next largest sheet S is used, the fourth flapper 69 rotates upward and discharges the sheet S from the third discharge roller pair 63. 5 if the smallest sheet S is used
The flapper 70 rotates upward to discharge the sheet S from the fourth discharge roller pair 64.

Sheet S discharged onto intermediate tray 29
Is an auxiliary roller 7 that rotates counterclockwise in the figure.
1, the rotary shutter 44 in which the leading end of the sheet is raised
Is transported until it comes into contact with. In this case, the leading end of the sheet is guided by a movable sheet guide 72 which is set in an inclined state as shown by a dotted line so that the curl is suppressed. The auxiliary roller 71 stands by at the position shown by the solid line when the sheet is discharged, and conveys the sheet S by descending as shown by the dotted line immediately after the sheet is discharged. Movable seat guide 7
An opening is formed in 2 to allow the auxiliary roller 71 to move up and down.

The sheets S stacked on the intermediate tray 29 are sequentially fed out from the uppermost sheet by an auxiliary roller 71 rotating counterclockwise in FIG. In this case, the auxiliary roller 71 descends from the standby position shown by the solid line as shown by the dotted line to feed out the sheet S. Further, the movable shutter 44 guides the sheet S which has been fed out while falling down in an inclined state to the nip of the separation roller pair 47.

With respect to the sheet S fed out by the auxiliary roller 71, only the uppermost sheet 1
The sheet is separated and sent to the registration roller pair 13 in the rotation stopped state via the conveyance roller pairs 9 to 12.

In the case of the double-sided mode, the sheet S sent to the vertical path 23 is transported by the transport rollers 24 to 26 into the second path.
7 and sent to the discharge path 60 by the carry-in roller pair 28. In the case of this double-sided mode, all the flappers 66 to 70 of the discharge path 60 are rotating downward. Then, the sheet S sent to the discharge path 60 is conveyed to the terminal U-turn portion 73 by each of the discharge roller pairs 61 to 65, and the image forming surface is turned upward by the discharge roller 74 and the discharge roller 75 on the intermediate tray 29. Is discharged to in this case,
The leading end of the sheet is guided by a movable sheet guide 72 which is set in an inclined state as shown by the solid line, so that the curl is suppressed.

Sheet S discharged onto intermediate tray 29
Is an auxiliary roller 7 that rotates counterclockwise in the figure.
By 1, the sheet is conveyed until the leading end (the trailing end of the sheet at the time of discharge) comes into contact with the movable shutter 44 that is standing up. In this case, the leading end of the sheet is guided by a movable sheet guide 72 which is set in an inclined state as shown by a dotted line so that the curl is suppressed. The auxiliary roller 71 stands by at the position shown by the solid line when the sheet is discharged, and conveys the sheet S by descending as shown by the dotted line immediately after the sheet is discharged.

The sheets S stacked on the intermediate tray 29 are re-fed in order from the top sheet by the auxiliary roller 71 as in the case of the multiplex mode.

In the discharge path 60 of this embodiment, the area 60A including the pair of discharge rollers 61 to 64 is a multi-mode discharge section, and the area 60B downstream of the area 60A is a double-side mode discharge section.

[0022]

However, in the above-described conventional example, in the duplex mode and the multiplex mode, the sheet S to be ejected is delayed until the leading end of the sheet is brought into contact with the rotary shutter 44 by the auxiliary roller 71. It is slightly extended in consideration of the fact that there is. Therefore, there were the following disadvantages.

When the sheet S is conveyed by the auxiliary roller 71 even after the leading end of the sheet comes into contact with the rotary shutter 44, the sheet S loops upward between the auxiliary roller 71 and the rotary shutter 44. When the auxiliary roller 71 rises for the next discharge, the sheet S moves upstream on the intermediate tray due to the force of the loop to return suddenly, adversely affecting the sheet S to be aligned and causing a stacking defect. Was.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of suppressing an increase in a loop amount of sheets in an intermediate tray and improving sheet stackability.

[0025]

According to a first aspect of the present invention, there is provided a sheet material having an image formed on one side, and an image forming method for forming an image on the one side or the other side. Sheet material stacking means for re-feeding the sheet material for re-feeding to the forming unit; and conveying rotation for conveying the sheet material by pressing and rotating the sheet material stacked on the sheet material stacking means for re-feeding. Body, and a position regulating member that regulates the position of the sheet material by temporarily abutting the leading edge of the conveyed sheet material, wherein the leading edge abuts on the position regulating member. When the loop formed at the front end portion by the sheet material conveyed after the predetermined time exceeds a predetermined size, a press-contact releasing means for releasing the press-contact of the conveyed rotating body against the sheet material is provided. .

With this configuration, even after the leading edge of the sheet material abuts against the position regulating member, the transport rotating body further rotates and transports the sheet material, so that the leading edge portion of the sheet material is formed to be curved. If the loop exceeds a predetermined size, the pressing of the conveying rotating body is released by the pressing release means, and the sheet material is no longer conveyed, so that the loop at the leading end of the sheet material exceeds the predetermined size. Never. Therefore, the increase in the loop amount is suppressed, and when the press-contact of the conveyance rotating body is released, the sheet material moves to the upstream side in the conveyance direction by the repulsive force and does not adversely affect the sheet material to be aligned, and the stacking performance is improved. Can be improved.

According to a second aspect of the present invention, in the first aspect, the press-contact releasing means comprises a sheet material guiding member for guiding a sheet material conveyed by the conveying rotating body, and the sheet material guiding member is Has an extension in the direction of material transport,
A pressure receiving portion pressed by the loop of the sheet material, an operating portion engaged with the transport rotating body, and a fulcrum portion provided on the upstream side of the action portion in the sheet material transport direction, and the fulcrum portion is provided. It is rotatably supported about the center, and the transport rotating body is moved in a direction away from the sheet material by a pressing force acting on the pressure receiving portion.

When the loop at the leading end of the sheet material guided by the sheet material guiding member exceeds a predetermined size,
When the loop presses the pressure receiving portion, the sheet material guide member rotates around the fulcrum. At this time, since the action portion is formed between the pressure receiving portion and the fulcrum portion, the sheet material guide member is moved in a direction away from the sheet material to release the pressure contact.

With this configuration, the press-contact of the conveying rotating body can be released by the sheet material guiding member, so that an increase in the amount of loops can be suppressed without providing a new member, thereby preventing defective stacking. Can be. Also, since the sheet material guide member releases the pressure contact by the principle of leverage,
Even when the pressing force due to the loop of the sheet material is small, the transport rotating body can be easily separated from the sheet material.

Further, the sheet material guide member only needs to be engaged so as to move the transport rotating body with the rotation, and does not necessarily need to be supported via a shaft hole or the like.

According to a third aspect, in the second aspect, the transport rotating body is rotatably supported by the operating portion.

When the transport rotating body is provided integrally with the sheet material guiding member as described above, the pressing of the transport rotating body can be reliably released by the rotation of the sheet material guiding member. Also,
It is also possible to reduce the number of parts and simplify assembly affirmation.

According to a fourth aspect of the present invention, in the second or third aspect, the sheet material guide member is rotated by bringing the fulcrum into contact with the refeeding sheet material stacking means main body. And

When the pressure receiving portion of the sheet material guide member is pressed by the loop of the sheet material and the fulcrum portion rotates while contacting the sheet material, a rubbing sound due to friction between the fulcrum portion and the sheet material or a sheet material is generated. Abrasion may occur,
If the fulcrum portion is configured to abut the sheet material stacking means for re-feeding so as not to contact the sheet material, no rubbing noise or scratches are generated, and a low level during operation of the apparatus is achieved. Noise can be reduced and the quality of the conveyed sheet material can be improved.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a partial configuration of a copying machine as an image forming apparatus according to a first embodiment of the present invention. The image forming apparatus according to the present embodiment has the same configuration as the conventional example except for a part of the configuration. Therefore, here, the configuration of the different parts will be described along the flow of the sheet S. The same members are denoted by the same reference numerals.

Intermediate tray 2 in multiplex mode and duplex mode
The sheet S discharged onto the sheet 9 is conveyed by an auxiliary roller 31 as a conveying rotating body rotating in a counterclockwise direction in the figure until the sheet S comes into contact with a movable shutter 44 as a position regulating member at which the leading end of the sheet stands. . In this case, the leading end of the sheet is guided by a movable sheet guide 32 as a sheet material guide member set in an inclined state as shown by a solid line, so that the curl is suppressed. The auxiliary roller 31 stands by at the position shown by the solid line when the sheet is discharged, and after the sheet is discharged, descends as shown by the dotted line to convey the sheet S.

When the leading end of the sheet abuts on the movable shutter 44 and the sheet S is conveyed by the auxiliary roller 31 thereafter, a loop is formed between the auxiliary roller 31 and the movable shutter 44.

Next, the pressure receiving portion 32a downstream from the auxiliary roller 31 rotatably supported by the action portion 32a of the movable sheet guide 32 is pushed up by the upward pressing force of the loop.

On the other hand, a fulcrum portion 32c of the movable sheet guide 32 which comes into contact with the sheet S upstream of the auxiliary roller 31 becomes a fulcrum, and the auxiliary roller 31 is pushed up by a lever.
Therefore, the conveyance force of the auxiliary roller 31 to the sheet S decreases, and the loop amount can be prevented from further increasing.

(Second Embodiment) FIG. 2 shows a partial configuration of an image forming apparatus (copier) according to a second embodiment of the present invention.

FIG. 2 differs from FIG. 1 according to the first embodiment only in the shape of the movable sheet guide. Portions having the same configuration as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the movable sheet guide 33 according to this embodiment, an elongated hole 34 is formed in the action section 33c in a direction substantially perpendicular to the sheet conveying direction, and the auxiliary roller 31 is pivoted through the elongated hole 34. Supported.

In the movable sheet guide 33 shown in FIG.
The fulcrum portion 33c comes into contact with a part of the intermediate tray 29, and the auxiliary roller 31 is pushed up using this as a fulcrum.

As described above, the rubbing noise due to the friction when the sheet comes into contact with the upstream of the auxiliary roller of the movable sheet guide and the rubbing of the sheet do not occur.

[0046]

As described above, according to the first aspect of the invention, even after the leading end of the sheet material comes into contact with the position regulating member, the transport rotating body continues to rotate and transports the sheet material. If the loop formed by curving the leading end of the sheet material exceeds a predetermined size, the pressure contact of the conveying rotating body is released by the pressure releasing means, and the sheet material is no longer conveyed. Loop does not exceed a predetermined size. Accordingly, the increase in the loop amount is suppressed, and when the press-contact of the conveying rotating body is released, the sheet material does not adversely affect the aligned sheet material by moving to the upstream side in the conveying direction due to the repulsive force, and the stacking failure. Can be prevented.

According to the second aspect, when the loop at the leading end of the sheet material guided by the sheet material guiding member exceeds a predetermined size, the sheet material guiding member rotates about the fulcrum. Since the transport rotating body is moved in the direction away from the sheet material to release the pressure contact, the increase in the loop amount can be suppressed without providing a new member, and the stacking failure can be prevented. Further, since the sheet material guide member releases the pressure contact by the leverage principle, even when the pressing force due to the loop of the sheet material is small, the transport rotating body can be easily separated from the sheet material.

According to the third aspect of the present invention, the transport rotating body is rotatably supported at the action portion and is formed integrally with the sheet material guiding portion, so that the transport rotating member is reliably rotated by the rotation of the sheet material guiding member. The pressure contact of the body can be released. In addition, the number of parts can be reduced to simplify assembly affirmation.

According to the fourth aspect of the present invention, since the fulcrum of the sheet material guide member abuts the sheet material stacking means main body for re-feeding and does not come into contact with the sheet material, rubbing noise and scratches may occur. In addition, the noise during operation of the apparatus can be reduced and the quality of the conveyed sheet material can be improved.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing a partial configuration of an image forming apparatus (copier) according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional side view showing a partial configuration of an image forming apparatus (copier) according to a second embodiment of the present invention.

FIG. 3 is a vertical sectional side view showing the entire configuration of a conventional image forming apparatus (copier).

[Explanation of symbols]

 29 Intermediate tray 31 Auxiliary rollers 32, 33 Movable sheet guide 32a Pressure receiving part 32b, 33b Working part 32c, 33c Support point S Sheet

Claims (4)

[Claims] 1. A re-feeding sheet material for stacking a sheet material on which an image is formed on one surface to re-feed the image material on an image forming portion to form an image on the one surface or the other surface. Stacking means, a conveying rotating body for pressing and rotating the sheet material stacked on the re-feeding sheet material stacking means to convey the sheet material, and temporarily abutting the leading end of the conveyed sheet material. And a position regulating member for regulating the position of the sheet material, wherein a loop formed at the leading end by the sheet material conveyed even after the leading end abuts on the position regulating member is provided. An image forming apparatus, comprising: a press-contact release unit for releasing the press-contact of the conveyed rotator against a sheet material when the size exceeds a predetermined size. 2. The pressure-releasing means comprises a sheet material guiding member for guiding a sheet material conveyed by the conveying rotating body, wherein the sheet material guiding member has an extension in a conveying direction of the sheet material; A pressure receiving unit pressed by the loop of the sheet material, an operating unit engaged with the transport rotating body, and a fulcrum provided upstream of the operating unit in the sheet material transporting direction. The image forming apparatus according to claim 1, wherein the image forming apparatus is rotatably supported as a center, and moves the transport rotating body in a direction away from a sheet material by a pressing force acting on the pressure receiving unit. 3. The image forming apparatus according to claim 2, wherein the transport rotator is rotatably supported by the operation section. 4. The image forming apparatus according to claim 2, wherein the sheet material guide member is rotated by bringing the fulcrum portion into contact with the refeeding sheet material stacking means main body.