JP2002012336A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device for facilitating jam treatment for a transfer material in a paper refeed and carriage path. SOLUTION: When a release lever 46 is pulled, a cam 41-1 is rotated to cause the run of a supporting part 41-1a out of a lower carriage guide 27 to make the lower carriage guide 27 lower and open at its end. At the same time, a canceling arm 43 is rotated to cancel the pressure of a paper refeeding roll 30 on a paper refeeding roller 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a printer, a facsimile, a copying machine, etc. having a double-sided image forming apparatus.

[0002]

2. Description of the Related Art A laser beam printer 101 shown in FIG. 7 will be described as an example of a conventional double-sided image forming apparatus. The laser beam printer 101 can form an image on both sides of a sheet as well as on one side thereof. The laser beam printer 101 includes an image forming section 102 for forming an image and a sheet re-feeding section 103 for re-feeding a sheet. Is done.

The image forming section 102 includes a cassette 104 for stacking sheets and a feeding unit 1 including a feeding roller 106.
05, process cartridge 1 including photosensitive drum 108
07, a transfer roller 109, a fixing unit 110, a laser scanner unit 112, a sheet discharge stacking table 116
Discharge section 113 including the controller board 111
It has.

[0004] The sheets P stacked on the cassette 104 are
When the controller board 111 receives the print signal,
The sheet is separated and fed one by one by the feeding roller 106, conveyed in the order of the nip between the photosensitive drum 108 and the transfer roller 109 and the fixing unit 110, and an image is formed on the sheet P.

When the controller board 111 has received a signal for single-sided printing, the sheet P is sent as it is to the sheet discharge section 113 and discharged onto the sheet discharge stacking table 116. If the controller board 111 has received a signal for double-sided printing, the sheet
03 is sent.

The sheet re-feeding / conveying unit 103 includes a flapper 1
39, curl removing roller pair 134 and transport roller pair 135
137, switchback roller pair 136
, A lateral registration correcting unit 123 including the skew feeding roller 126, and a re-feed roller pair 122.

The sheet P conveyed to the sheet re-feeding conveyance unit 103 by the flapper 139 upon receiving the double-sided printing signal is
It is sent from the transport path 137 to the switchback unit 138. Here, the switchback roller 136 is rotated in the reverse direction, and the sheet P is rotated in a state in which the leading end and the trailing end are reversed.
Transported to

[0008] The sheet P that has reached the lateral registration correction unit 123
Since the skew feeding force is exerted by the inclined skew feeding roller 126,
While being conveyed, it approaches the reference plate 124 side. Eventually, the sheet P arrives at and abuts on the reference plate 124, and the sheet end is conveyed along the reference plate 124, corrected to a correct position without skew or displacement, and conveyed on the conveyance path A.

The sheet P corrected for the lateral registration as described above
Is sent again to the image forming unit 2 by the sheet re-feed roller 122 to form an image on the second side, and the sheet discharging unit 11
3 and stacked on the sheet discharge table 116.

[0010]

However, after the recording paper P is conveyed to the conveyance path A, if the recording paper P stays in the conveyance path A for some reason, the recording paper P is removed. There are the following problems to remove.

1. The recording paper P must be removed by putting a hand in the narrow conveyance path A. Depending on the position where the recording paper P stays, the recording paper P may not be reachable, and the recording paper P may not be removed. Was.

2. Depending on the staying position of the recording paper P, the recording paper P is sandwiched between nips such as conveyance rollers, and if the recording paper P is forcibly pulled out, the recording paper P may be broken. If the torn recording paper P remains in the transport path A, the recording paper P may block the transport path A and cause a transport failure such that the next transported recording paper P stays. .

An object of the invention according to the present invention is to solve the above-described problem. When the recording paper P stays in a narrow conveyance path, a user stays. An object of the present invention is to provide an image forming apparatus capable of easily removing recording paper.

[0014]

According to a first aspect of the present invention, there is provided an image forming section for forming an image on a sheet, and a method for forming an image on the second side of the sheet after forming the image on the first side of the sheet. A sheet transport path for transporting the sheet to the image forming unit; opening means for lowering the downstream side of the sheet transport path in the transport direction to open the sheet transport path; and a sheet downstream of the sheet transport path in the sheet transport direction. And a re-feeding conveyance unit for causing a re-feeding roller to re-feed rollers disposed on the side of the image forming apparatus, wherein the opening unit is operated to open the sheet conveyance path, and It is characterized by having a re-feed roller and a pressure releasing means for releasing the pressure of the re-feed roller.

According to a second aspect of the present invention, in the first aspect, the pressure release means keeps maintaining the pressure release state of the re-feed roller and the re-feed roller when the sheet conveying path is opened. When closed, the pressurized state of the re-feed roller and the re-feed roller is restored again.

According to a third aspect of the present invention, in any one of the above aspects, the opening means is driven by a cam for supporting an opening-side end of the sheet conveying path, a release lever interlocked with the cam, and the cam. A release arm for supporting the re-feed roller so as to be able to contact and separate from the cam, an elastic member for returning the cam to a fixed position, and pressing the re-feed roller against the re-feed roller. And an elastic member for performing the operation.

In a fourth aspect based on the third aspect, the release lever is connected to a fulcrum of the cam on the same side as a point of action with the release arm.

According to a fifth aspect of the present invention, in the third aspect, the release lever is connected to a fulcrum of the cam on a side opposite to a point of action with the release arm.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment will be described with reference to FIGS. The first embodiment is a laser beam printer as an example of a two-sided image forming apparatus. The laser beam printer 1 can form an image on both sides of a sheet as well as on one side thereof, and has an image forming section 2 for forming an image and a sheet re-feeding / conveying section 3 for reversing the sheet. .

The configuration of the image forming section 2 will be described with reference to FIG. FIG. 1 is a main sectional view of the present embodiment.

A plurality of sheets P can be stacked on the cassette 4. The feeding unit 5 is a unit that separates and feeds the sheets P on the cassette 4 one by one by a sheet feeding roller 6 or the like. The process cartridge 7
The photosensitive drum 8 and process means (charging means, developing means, cleaning means) acting on the photosensitive drum 8 are integrally provided, and are detachable from the printer main body.

The transfer roller 9 electrostatically transfers the toner image formed on the photosensitive drum 8 to the sheet P passing between the photosensitive drum 8 and the transfer roller 9. .

The fixing unit 10 semi-permanently fixes the toner image on the sheet on which the toner image has been transferred. The controller board 11 controls the laser beam printer 1 and also has a function of forming an image signal of a connected computer (not shown).

The laser scanner unit 12 forms a latent image by irradiating the photosensitive drum 8 with laser light turned on and off in accordance with an image signal generated by the controller board 11. Roller after fixing 17
Makes a nip with the first roller 18 and fixes the fixing unit 1
The sheet P coming out from 0 is ejected by the discharge guide 20 and the flapper 3
9 is conveyed.

The paper discharge section 13 has a discharge roller 14 and a discharge roller 15 facing each other to constitute a discharge means. The discharge paper loading table 16 includes the discharge roller 14 and the discharge roller 1.
5 is a table for receiving the sheet discharged.

Next, the operation of the image forming section 2 will be described.

When the image forming unit 2 receives a print command, the sheets P stacked in the cassette 4 are separated and fed one by one by a paper feed roller 6, and the sheets P are transferred between the photosensitive drum 8 and the transfer roller 9 in the process cartridge 7. Sent between the nips. The print command is sent to the controller board 1 when image information is sent from a personal computer (not shown) or the like.
Occurs via 1 A bit image (laser light) of image information is radiated from the laser scanner unit 12 together with the print command onto the photosensitive drum, and a latent image is formed on the photosensitive drum 8 in accordance with the bit image. The image is developed to form a toner image.

The toner image formed on the photosensitive drum 8 is transferred to a sheet P at the nip between the photosensitive drum 8 and the transfer roller 9.
Is transferred to Then, the sheet P to which the toner image has been transferred is sent to the fixing unit 10 and heated and pressed by the fixing unit 10. As a result, the toner image is fixed on the sheet P semi-permanently.

The sheet P, on which the toner image is fixed on the first surface of the transfer material by the fixing unit 10,
The sheet is sent to the nip of the first roller 18 facing the sheet feeder, and is sent to the sheet ejection section 13 via the ejection guide 20 and the flapper 39. At this time, the position of the flapper 39 is the position indicated by the solid line in FIG. When the controller board 11 has received a signal for single-sided printing, the sheet P is nipped and conveyed by the discharge roller 14 and the discharge roller 15 and discharged to the discharge stacking table 16. Here, the single-sided printing signal is a signal sent from the personal computer (not shown) to the controller board 11 in the same manner as the print signal and the image signal.

When the controller board 11 has received a signal for double-sided printing, the discharge roller 14 rotates in the reverse direction after the trailing edge of the sheet has passed the leading edge of the flapper 39, and
Move to the position indicated by the chain line (FIG. 1). Thus, the sheet P is continuously sent to the sheet re-feeding / conveying section 3. The discharge roller 14 is driven by a motor (not shown) independent of other rollers.

Next, the configuration of the sheet re-feeding / conveying section 3 is shown in FIG.
It is described using. Here, the sheet re-feeding / conveying section 3 is configured around a paper conveying path starting from the pair of discharge rollers 14 and reaching a junction 21 with the conveying path from the cassette 4.

The post-fixing roller 17 has the first
In addition to the roller 18, the second roller 19 is urged toward the roller 17 after fixing. Sheet P after sheet reversal
Is fed into a nip formed by the second roller 19 and is nipped and conveyed.

In the present embodiment, the transport path from the pair of discharge rollers 14 to the nip of the second roller 19 uses the same transport path as the discharge transport path on the first surface. Here, two or more post-fixing rollers 17 are provided in the paper width direction in order to suppress the rotational movement of the sheet P during conveyance. Both the first roller 18 and the second roller 19 are fixed to the roller 1 after fixing.
Two or more are arranged similarly to 7.

The lower conveying guide 27 guides most of the lower side of the sheet conveying surface and is supported by a supporting fulcrum shaft 48.
As shown in FIG. 3, it is configured to be rotatable downward.

When the transport lower guide 27 is stored, it is supported by the pressure release cam 41-1.
The stopper is released by pulling the pressure release lever 46 attached to 1 and the transport lower guide 27 is opened. The pressure release lever 46 is connected to the point of action where the pressure release cam 41-1 pushes up the release arm 43 described below.

On the downstream side of the horizontal registration correction unit 23, a nip is formed by the re-feed roller 22 and the roller 30 opposed thereto. The re-feed roller 22 holds the sheet P corrected for the lateral registration.
Are arranged in the paper width direction so as not to skew again. Upper and lower frame members 31 including a guide for connecting the pair of re-feed rollers 22 to the lower conveyance guide 27 of the lateral registration correction unit 23 simultaneously hold the rollers 30 facing the re-feed rollers 22. The position of the re-feed roller 22 in the paper feeding direction is within the range of the minimum sheet length from the lateral registration correction roller 25 shown in FIG. Further, downstream of the re-feed roller 22,
There is a junction 21 with the cassette feeding path on the first side.

As shown in FIG. 2, the roller 30 is supported by a roller holder 44, and is pressed against the re-feed roller 22 by a spring member 45 such as a torsion coil spring.
The roller holder 44 is fixed on a roller holder shaft 447 with a parallel pin 49, and a release arm 43 is fixed to an end of the roller holder shaft 48.

Next, the operation of the sheet re-feeding / conveying section 3 will be described.

When the double-sided printing signal is received, the discharge rollers 14 and 15 rotate in the reverse direction after the trailing edge of the sheet P passes from the leading edge of the flapper 39 as described above, and the position of the flapper 39 moves to the position indicated by the two-dot chain line. (FIG. 1). The sheet P is nipped and conveyed by the post-fixing roller 17 and the second roller 19 in a state where the leading end and the trailing end are reversed, and is conveyed to the lateral registration correction unit 23.
The sheet P having been subjected to the lateral registration correction is again fed into the image forming unit 2 by the re-feeding roller 22, and the image on the second surface whose writing position is adjusted based on the reference surface 24a is formed.
The sheet is sent to the sheet discharge section 13 and is stacked on the sheet discharge table 6.

As shown in FIG. 4, when a paper jam occurs in the re-feeding / conveying section, one end of a release lever 46 at a front portion of the image forming apparatus is pulled in the direction B, whereby the conveying guide is pulled. The pressure releasing cam 41 supporting the 27
-1 rotates clockwise (in the direction C) about the fulcrum 47,
The support portion 41-1a is disengaged from the transport guide 27, and opens downward (D direction) while holding the jammed paper P. Furthermore, the tip 41-1b of the release cam 41-1 is
The lower portion of the release arm 43 is pushed up in the direction E, and the release arm rotates clockwise (the direction F) about the fulcrum 48,
The pressure of the roller 30 pressed against the re-feed roller 22 is released.
At this time, the release arm 43 is connected to the tip 41-1 of the release cam.
By being hooked on b, the pressure release state is maintained.

After the paper jam is cleared, the transport guide 27
Is lifted upward and stored, a part of the conveyance guide pushes up the release arm 43, and the release cam 41-1 rotates counterclockwise by the tension spring 42, stops at the position shown in FIG. It is supported again by the support part 41-1a. Also, the release arm 4 from which the release cam 41-1 has come off.
3 rotates counterclockwise by a spring member 45 that presses the rollers, and again presses against the re-feed roller 22.

(Second Embodiment) A second embodiment will be described with reference to FIG. 5 and FIG. FIG. 5 and FIG.
FIG. 10 is a cross-sectional view of the main part of the second embodiment, which is a part of the first embodiment.
Only the differences from the first embodiment will be described, and the others will be omitted.

In this embodiment, the release lever 46 is
With respect to the pivot of the pressure release cam 41-2, the pressure release arm 4
3 is connected to the side opposite to the action point side.

As described in the first embodiment, when a paper jam occurs in the re-feeding conveyance unit as shown in FIG.
When one end of the release lever 46 at the front of the image forming apparatus shown in FIG. 5 is pulled in the direction B, the pressure release cam 41-2 rotates counterclockwise (in the direction C), and the cam support 41-1 is rotated. 2a is disengaged from the transport guide 27 and opens downward (in the direction D) while holding the paper P jammed. Further, the distal end portion 41-2b of the release cam 41-2 pushes up the lower portion of the release arm 43 in the direction E, rotates clockwise (direction E) about the fulcrum 48 of the release arm, and rotates the sheet re-feed roller. The pressure of the roller 30 that is in pressure contact with 22 is released. The release arm 43 is maintained in the pressure released state by being hooked on the cam tip 41-2b.

After the paper jam processing, as shown in FIG. 6, when the lower conveyance guide 27 is lifted upward (F direction) and stored, a part of the conveyance guide pushes up the release arm 43 in the G direction. The release cam 41-2 locked by the release arm 43 is rotated clockwise (direction I) by the tension spring 42, stops at the position shown in FIG. 5, and again moves the lower conveyance guide 27 by the support portion 41-2a. To support. Further, the release arm 43 from which the release cam 41-2 has been disengaged is rotated counterclockwise (H direction) by the spring member 45 for pressing the roller, and again comes into pressure contact with the paper re-feed roller 22.

[0046]

As described above, according to the present invention,
In one operation, the opening function of a part of the conveyance path, and the opening of the conveyance unit nipped by the cam that is interlocked with the release lever to release the pressure of the re-feed roller and the re-feed roller pressed against the re-feed roller, , By releasing the pressure of the re-feed roller at the same time,
This operation can be performed with sufficient space for removing paper jams in the paper path in the paper re-feeding section and paper jams when the paper is caught in the nip of the paper re-feeding roller. The paper jammed recording paper can be led out without forcibly pulling out the paper caught in the nip, thereby improving usability.

[Brief description of the drawings]

FIG. 1 is a main cross-sectional view of a first embodiment.

FIG. 2 is a perspective view of the first embodiment.

FIG. 3 is a main cross-sectional view illustrating a paper jam process according to the first embodiment.

FIG. 4 is a cross-sectional view extracting main parts of FIG. 3;

FIG. 5 is a sectional view of a main part of the second embodiment.

FIG. 6 is an essential part cross-sectional view of the second embodiment.

FIG. 7 is a schematic configuration diagram showing a conventional double-sided image forming apparatus.

8 is a cross-sectional view illustrating the paper jam process of FIG.

[Explanation of symbols]

 2 Image Forming Unit 3 Sheet Refeeding / Conveying Unit 22 Refeeding Roller 23 Lateral Registration Correction Unit 25 Lateral Registration Correction Roller 26 Slanting Roller 27 Conveying Lower Guide 30 Roller 31 Frame Member 41 Release Cam 42 Release Spring 43 Release Arm 44 Roller Holder 45 Roller spring 46 Release lever 47 Cam fulcrum 48 Arm fulcrum

Claims (5)

[Claims] An image forming unit for forming an image on a sheet;
After forming an image on the first surface of the sheet, a sheet conveying path for conveying the sheet to the image forming section again to form an image on the second surface of the sheet, and a downstream side of the sheet conveying path in the conveying direction is lowered. Opening means for opening the sheet conveying path, and a sheet re-feeding section for re-feeding a sheet re-feeding roller with respect to a sheet re-feeding roller arranged downstream of the sheet conveying path in the sheet conveying direction. In the image forming apparatus, the image forming apparatus further includes a pressure releasing unit that releases the pressure of the re-feed roller and the re-feed roller while operating the opening unit to open the sheet conveying path. Image forming apparatus. 2. The pressure releasing means according to claim 1, wherein the pressure releasing means keeps maintaining the pressure releasing state of the re-feed roller and the re-feed roller when the sheet conveying path is open, and when the sheet is closed, the re-feeding means. An image forming apparatus wherein the pressurized state of the paper roller and the re-feed roller is restored again. 3. The sheet feeding device according to claim 1, wherein the opening means includes a cam for supporting an opening-side end of the sheet conveying path, a release lever interlocked with the cam, and the re-feeding mechanism driven by the cam. A release arm for supporting the paper roller so as to be able to contact and separate from the cam; an elastic member for returning the cam to a fixed position; and an elasticity for pressing the paper re-feed roller against the paper re-feed roller. An image forming apparatus comprising: a member; 4. The device according to claim 3, wherein the release lever is
An image forming apparatus, wherein the fulcrum of the cam is connected to the same side as the point of action with the release arm. 5. The image forming apparatus according to claim 3, wherein the release lever is connected to a fulcrum of the cam on a side opposite to a point of action with the release arm.