JPH08239170A - Image forming device capable of recording on each side of paper - Google Patents

Abstract

PURPOSE: To facilitate recording on both sides of paper simply by installing upper and lower refeed means, without preparing any special mechanism or parts in an image forming device main body. CONSTITUTION: Paper P' in a paper tray 52 is fed to a register roller 25 via a passage 59 by rotation of a paper feeding roller 58, recording is made on the first side, and then the paper P' is allowed to enter a passage 101a from an output port 40a. While the paper P' is passing, a guide plate closing the passage 101a bents downward, and a switch guide 104 rotates in the direction of the arrow D to temporarily unload the paper onto a paper support 107. A detection means S detects that the rear end of the paper P' has passed the guide plate 102 and also detects the holding state of a pair of rollers 103, and then reverses the pair of rollers 103 to feed the paper P' to a passage 101b. The paper P' is carried by pairs of rollers 103, 108, 109, 110, 111, 201, 202 and is fed to the register roller 25 by a sending roller 203 and a paper feeding roller 23. A detection means S1 detects the start of recording on the second side and the termination of refeed, and the paper P' with recording made on the second side is unloaded onto an unloading tray portion 106 by the pair of rollers 103.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus used for a printer or the like and capable of recording on both sides of paper.

[0002]

2. Description of the Related Art Recently, due to environmental problems such as deforestation, there is a growing demand for saving paper resources such as the use of recycled paper, and DTP (Desk Top Publishin) using a personal computer.
In the case of printing products by the spread of g), in the image forming apparatus adopting the electrophotographic method, the image forming apparatus capable of automatically recording not only on one side of the sheet but on both sides of the sheet is required, and is in the market. I am turning around.

According to the description of JP-A-64-92135,
An image is recorded on the first side by a main conveyance path that is a conveyance path from the lower sheet feeding section to the image recording section, the image fixing section, and the discharging section, and the image-recorded sheet is reversed and main conveyance is performed again. The sub-conveyance path, which is a conveyance path for guiding the second path,
The image is recorded on the surface. A first paper transport system unit in which a part of members constituting the sub transport path are integrated;
The second paper transport system unit in which the members forming the sub-transport path and the main transport path are integrated is rotatable with respect to the main body of the image forming apparatus with the support shaft as the fulcrum, and the main transport path and the sub-transport path are provided. The road is open.

Further, the image forming is composed of a fixed unit and a moving unit, and the moving unit is rotated around a support shaft provided in the fixed unit as a fulcrum to take out jammed paper and replace consumables. In the device, double-sided recording is possible on the image forming apparatus main body that has a conveyance path in which the paper from the paper feeding section rises from the bottom up substantially vertically and is conveyed to the stack section for discharging the upper part of the main body through the image recording section. For this reason, a sheet re-conveying path means for re-conveying the sheet to the image recording section is detachably provided, and its mounting surface is configured to extend to the operation surface side of the moving unit of the image forming apparatus main body and the upper portion thereof. There is.

The image forming apparatus is provided with the sheet re-conveying path configured as described above, and recording is performed on both sides of the sheet.

[0006]

However, the image forming apparatus capable of recording on both sides of the sheet having such a structure is originally provided with a sub-conveying path for recording on both sides of the sheet in the main body of the image forming apparatus. For a user who does not perform double-sided recording, a costly image forming apparatus is purchased because the sheet guide member, the roller, and the like necessary for the first sheet conveying system unit and the sub conveying path are provided. The financial burden was heavy.

In another image forming apparatus, the sheet re-conveying means can be attached to and detached from the image forming apparatus, so that it can be used only by a user who needs it. However, in order to process a sheet jam and replace consumables. Further, the moving unit rotates about the fulcrum of the fixed unit. Thus, when the sheet reconveying path means is attached to the moving section unit, the support shaft of the fixed section unit must support its own weight and the rotation of the moving section unit and the fixed section unit to which the sheet reconveying path means is attached. A special mechanism such as increasing the rigidity of the fulcrum is required, and the total weight increases and the installation space on the operation surface side increases.

Further, in order to perform recording on both sides of the paper, it is necessary to provide a mechanism for reconveying the paper and to reverse the paper before being conveyed to the image recording section. The reversal of the paper is performed inside the paper reconveying means. However, the space of the sheet re-conveyance path means is limited, and there is a problem in the case where the radius of curvature of the sheet cannot be made large and the sheet is thick and the stiffness is high.

The present invention is to solve the above-mentioned problems of the prior art, and it is not necessary to prepare in advance a special mechanism or part for performing double-sided recording in the main body of the image forming apparatus. Double-sided recording is possible by mounting the conveying means when double-sided recording is required, and the installation space is small and the maintainability is good, and the cost of the main body of the image forming apparatus and the mechanism are not complicated. An object is to provide a possible image forming apparatus.

[0010]

In order to achieve this object, the present invention provides a paper re-conveying to the image recording means for recording on the second side of the paper which has finished recording on the first side. In an image forming apparatus capable of recording on both sides of a sheet having a conveying path, an upper re-conveying unit having a sheet re-conveying path from a discharge section at an upper part of the image forming apparatus to a rear section, and a sheet re-conveying section at a lower part of the image forming apparatus. It is characterized in that it has a lower re-conveying means provided with a conveying path, and the sheet re-conveying path is formed in a substantially U shape so as to surround the upper part, the rear part and the lower part of the image forming apparatus.

Further, the upper re-conveying means is detachably provided in the image forming apparatus.

Further, the lower re-conveying means is characterized in that it can be mounted in a space in which a paper feed cassette for paper feeding which is detachably provided in the image forming apparatus is taken out.

Further, the upper re-conveying means includes a sheet support for temporarily placing the recording sheet on the first side on the upper portion and a second stack for placing the recording sheet on the second side. It is characterized in that the parts are provided so as to overlap.

Further, the upper re-conveying means is configured such that the first re-conveying means is mounted when the first stack portion on which the recorded sheets of the image forming apparatus are placed and the upper re-conveying means is not mounted. A conveyance path for re-conveying the sheet is formed between and.

Further, it is characterized in that the sheet re-conveyance path can be opened.

Further, the upper re-conveying means is provided with a reversing means which is adjacent to the discharging section of the image forming apparatus and which reverses the sheet discharged from the discharging section.

Further, the upper re-conveying means is characterized in that the ejected paper stopper used in the first stack section can be attached to the second stack section of the upper re-conveying means. It was done.

[0018]

According to the above construction, the sheet re-conveying path capable of double-sided recording is formed by attaching the upper re-conveying means and the lower re-conveying means to the image forming apparatus.

Further, when double-sided recording is required, it is possible to attach it and use its function.

Further, even if the two-sided function is set up, a large amount of one-sided recording can be performed by replacing the sheet feeding cassette.

Further, a sheet support for temporarily supporting the sheet with one side recorded can be arranged so as to overlap with the upper part of the second stack portion on which the sheet with double-sided recording is placed, so that the installation space can be reduced.

Further, by stacking the upper re-conveying means on the upper part of the first stack portion for mounting the recorded sheets on the first side, the sheet re-conveying path requires a special conveying path member therebetween. Can be configured without.

Further, the sheet re-conveyance path can be opened and closed for maintenance.

Further, the sheet discharged from the discharge section of the image forming apparatus can be reversed.

Further, the first sheet stacking portion of the image forming apparatus and the second sheet stacking portion of the upper re-conveying means can also serve as the discharged sheet stopper.

[0026]

Embodiments will be described in detail below with reference to the drawings. FIG. 1 is a sectional view of a substantially central portion of an image forming apparatus provided with an upper re-conveying path means and a lower re-conveying means capable of recording on both sides of a sheet according to an embodiment of the present invention. Around the photoconductor 1 rotating in the direction of the arrow, the photoconductor 1 is charged with the laser beam L by the charging unit 2, the cleaning unit 3, and the laser optical system 4.
A developing unit 6 and a transfer unit 7 for forming a latent image and supplying the toner 5 to visualize the latent image are arranged on the top. The laser beam L from the laser optical system 4 forms an optical path bent in a substantially inverted U-shape, and the laser optical system 4 including the polygon motor 4a and the like includes the photoconductor 1, the charging unit 2, and the cleaning unit. A sensor 10 for detecting the toner 5 is located below a cartridge 8 (described in FIG. 2 described later) in which the means 3, the laser optical system 4, the toner 5, and the developing means 6 are integrated. It is between the laser optical systems 4.

Further, the paper P in the paper feed cassette 20 which is arranged in the lower part of the main body of the image forming apparatus of FIG. 1 and which is detachable in the direction of arrow a is supported by the intermediate plate 21 and is armed by the force of a spring (not shown). It is pressed against the paper feed roller 23 via 22. A command from a control unit (not shown) rotates the paper feed roller 23 to rotate the paper feed roller 23, so that the uppermost paper P in the paper feed cassette 20 is prevented from being double-fed by the separation pad 24.
1 is operated and the sheet is conveyed to the registration roller 25. Paper P
Is sent to the transfer means 7 at a timing synchronized with the image on the photoconductor 1. The sheet P on which an image is obtained from the photoconductor 1 by the transfer unit 7 is further conveyed to the fixing unit 30, passes between the fixing roller 32 having the heater 31 built therein and the pressure roller 33 which is in pressure contact, and is heated and pressed. The toner image can be fixed.

After that, the image-recorded sheet P is discharged and placed on the discharge tray section (first stack section) 41 with the image side facing down by the discharge roller 40 by operating the detecting means S. The cover 42, which constitutes the paper ejection tray section 41, includes a support shaft 43.
Is rotatably attached and can be opened.
Further, in order to correspond to the size of the discharged paper, the discharged paper stopper 44 is movable in the direction of the arrow b and is attachable to and detachable from the paper discharge tray section 41.

An operation surface is arranged on the upper right side of the main body of the image forming apparatus shown in FIG. 1, the operation panel 50 projects from the upper front surface of the moving part exterior 51, and the paper feed tray 52 is a spindle.
It is rotatably attached by 53. A power supply 61 and a printed circuit board 62 (controller board, engine driver board) are provided in a case 60 arranged on the left side of the image forming apparatus main body.
The electrical equipment and control means such as are stored.

Further, FIG. 2 is a sectional view of a substantially central portion showing a state where the cartridge is taken out from the image forming apparatus. As shown in FIG. 2, the fixed portion of the image forming apparatus, the transfer unit 7,
A moving unit including the fixing unit 30, the paper discharge roller 40, and the like is rotatable about a support shaft 53 as a fulcrum. By setting the openable state as described above, the jam processing of the paper P and the cartridge 8 are performed.
Replacement and maintenance are easy.

FIG. 3 shows the image forming apparatus shown in FIG. 1 in which the upper re-conveying means and the lower re-conveying means (hereinafter referred to as a conveyance cassette).
FIG. 3 is a cross-sectional view of a substantially central portion showing a state in which is attached. In FIG. 3, the upper re-conveying means 100 is attached to the image forming apparatus, the paper feed cassette 20 is removed, and the conveyance cassette 20 is replaced.
Wearing 0. The sheet re-transporting path is formed by the upper re-transporting means 100 and the transport cassette 200. As shown in FIG.
Since the upper re-conveying means 100 and the conveying cassette 200 are mounted so as to surround the upper portion, the rear portion, and the lower portion of the image forming apparatus in a substantially U-shape, the fan F of the fan F for preventing an excessive temperature rise in the main body of the image forming apparatus. The air outlet is provided on the side surface of the image forming apparatus (in the direction perpendicular to the paper surface).

Further, another sheet feeding cassette (not shown) is attached to the lower portion of the transport cassette 200, and the sheet fed from the sheet feeding cassette is fed to the registration rollers 25 through the passage 210 of the transport cassette 200. However, the case of feeding the paper P ′ in the paper feed tray 52 will be described here.

The middle plate 54 in the paper feed tray 52 is the paper feed tray 52.
A spring 55a provided therein pushes up the support shaft 56 so as to rotate about the support shaft 56. The separation pad 57 is also pushed up by the spring 55b and comes into contact with the paper feed roller 58.

The paper feed roller 58 rotates in the direction of the arrow in response to a paper feed command, so that the uppermost paper P'is conveyed through the conveyance path 59.
And reaches the registration roller 25. In the same manner as described with reference to FIG. 1, the sheet P ′ on which an image has been obtained enters the conveying path 101a from the upper discharge port 40a by operating the detecting means S. As shown in FIG. 3, the conveyance path 101a is normally covered with a flexible guide plate 102 made of a polyester material or the like.
When ‘′ is transferred from the paper discharge roller 40 to the roller pair 103, the sheet P ′ can pass above the flexible guide plate 102 downward. When the recording is not performed on both sides of the sheet P ′, the switching guide 104 is rotated around the support shaft 105 in the direction of the arrow U so that the image surface faces downward on the sheet discharge tray section (second stack section) 106. Ejected and placed.

Next, when recording on both sides of the paper P ', the switching guide 104 is rotated in the direction of arrow D to rotate the roller pair 1
Eject from 03 onto the paper support 107 temporarily. The state in which the trailing edge of the sheet P ′ has passed the guide plate 102 and the state in which the sheet P ′ is held by the roller pair 103 is detected based on the output of the detection means S, and the roller pair 103 is rotated in the reverse direction. The sheet P ′ recorded on the first side is conveyed to the reversing unit 113. The sheet P ′ is conveyed by the roller pair 103 forming the reversing section 113.
It is reversed by passing through the roller pair 108 via the lower part of 101b and the guide plate 102. Further, the sheet P ′ is conveyed along the sheet re-conveyance path by the roller pairs 109, 110, 111, 201 and 202.

The reversal of the sheet P'conveyed to the sheet reconveying path for recording on both sides is performed by temporarily ejecting it to the sheet support 107 provided on the upper portion of the sheet ejection tray section 106 and re-conveying it to the reversing section 113. Therefore, the upper space of the paper discharge tray unit 106 can be effectively used, and the radius of curvature of the paper P ′ can be freely determined by design. Therefore, it is possible to handle thick sheets of paper P ′ and sheets of high rigidity.

The delivery roller 203 is rotatably attached to a lever 205 rotatably supported by a support shaft 204, and is pressed against the paper feed roller 23 by a spring 206. It is sent to the registration roller 25 by the 203 and the paper feed roller 23. When the paper P'passes from the paper feed roller 23 to the registration roller 25, the detection means S1
Is detected, the start of recording on the second surface and the end of re-conveyance of the paper P ′ are detected.

An image is recorded again on the second surface of the paper P'with timing adjusted by the registration roller 25. The sheet P ′ having the images recorded on both sides is discharged onto the sheet discharge tray section (second stack section) 106 by the roller pair 103. In this case the first
The changeover guide 104 has an arrow U as in the case of recording only the surface of
Has been rotated in the direction of. Further, as the discharged paper stopper 44, the one used in the discharged paper tray portion (first stack portion) 41 of the image forming apparatus is replaced and used.

FIG. 4 is an explanatory view showing a method of attaching the upper re-transporting means and the transport cassette to the image forming apparatus. As shown in FIG. 4, the discharge tray unit 41 and the upper re-transporting unit 100 are provided.
A sheet re-conveyance path is formed between them. The roller pair 109 (see FIG. 3) that conveys the paper in the paper re-conveyance path is the upper re-conveyance unit 1.
A roller 109b facing the 00-side roller 109a is attached to the paper discharge tray section 41 via a leaf spring 112.

FIG. 5 is a cross-sectional view of a substantially central portion showing a state where the sheet reconveying path of the upper reconveying means is opened. As shown in FIG. 5, the upper re-conveying means 100 is rotatably attached to the upper surface thereof with a support shaft 120 as a fulcrum, and similarly rotatably attached to a rear surface portion thereof with a support shaft 121 as a fulcrum. in this way,
Since the sheet re-conveying path of the upper re-conveying means 100 can be opened, it is possible to easily carry out maintenance such as jam treatment of the sheet P'being conveyed.

Further, the transport guide 209 in the transport cassette 200
Can rotate about a support shaft 208 provided at the rear part as a fulcrum, and can open the sheet re-conveyance path with the conveyance cassette 200 pulled out (not shown). One roller of the roller pair 201, 202 is attached to the conveyance guide 209 so as to form a pair with the other roller when the conveyance guide 209 is closed and a sheet reconveyance path is formed. Therefore, it is possible to easily perform the jam processing of the sheet P ′ being transported in the transport cassette 200.

[0042]

As described above, according to the present invention,
If you want to add the double-sided recording function to the image forming device, it is possible by attaching the upper re-conveying means and the transfer cassette to the image recording device, so it is easy to add the double-sided recording function and the price of the image forming device is low. This reduces the financial burden on the user.

Further, since the upper re-transporting means and the transport cassette image forming apparatus can be selectively attached and detached, the image forming apparatus can be purchased at a low cost for a user who does not need the double-sided recording function, and when the function is required. It is economical because it can be adopted for.

Further, even if the image forming apparatus is set up in a form capable of double-sided recording, the paper feed cassette can be easily attached instead of removing the transport cassette, so that it is possible to cope with a large amount of single-sided recording. .

Further, since the paper support and the second stack portion are arranged in parallel in the horizontal direction, the size of the upper part of the installation space for the image forming apparatus can be reduced.

Since the sheet re-conveying path is formed by stacking the upper re-conveying means on the first stack section, the lower side of the sheet re-conveying path can be shared by the first stack section. It is possible to reduce the weight and cost of the upper re-transporting means.

Further, since the conveying path for re-conveying the sheet can be opened and closed, the jammed paper can be easily treated and the maintainability is improved.

Further, since double-sided recording is performed, the upper space of the discharge tray can be effectively used for reversing the paper, and the radius of curvature of the paper can be freely determined by design, so that thick or highly rigid paper is handled. You can

Further, since the ejected paper stopper can be used even when the double-sided recording function is added, it is not necessary to prepare two ejected paper stoppers, and the conventional ejected paper stopper is discarded when the double-sided function is added. There is an effect that it can be effectively used without waste.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a substantially central portion showing an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of a substantially central portion showing a state in which a cartridge is taken out from the image forming apparatus according to the exemplary embodiment of the present invention.

FIG. 3 is a cross-sectional view of a substantially central portion showing a state in which an upper re-conveying unit and a conveyance cassette are attached to the image forming apparatus according to the exemplary embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a method of attaching the upper re-transporting unit and the transport cassette to the image forming apparatus in the embodiment of the present invention.

FIG. 5 is a cross-sectional view of a substantially central portion showing a state in which a sheet reconveying path of an upper reconveying unit is opened in the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoconductor, 2 ... Charging means, 3 ... Cleaning means, 4 ... Laser optical system, 4a ... Polygon motor, 5
... toner, 6 ... developing means, 7 ... transfer means, 8 ... cartridge, 10 ... sensor, 20 ... paper feed cassette, 21,
54 ... middle plate, 22 ... arm, 23,58 ... feed roller, 2
4, 57 ... Separation pad, 25 ... Registration roller, 30 ... Fixing means, 31 ... Heater, 32 ... Fixing roller, 33 ... Pressure roller, 40 ... Paper discharge roller, 40a ... Discharge port, 41 ... Paper discharge tray section ( 1st stack part), 42 ... cover, 43, 5
3, 56, 105, 120, 121, 204, 208 ... Support shaft, 44 ... Ejection paper stopper, 50 ... Operation panel, 51 ... Moving part exterior, 52 ... Paper feed tray, 55a, 55b, 206 ... Spring, 59, 101a, 101b ... conveyance path, 60 ... case, 61 ...
Power supply, 62 ... Printed circuit board, 100 ... Top re-transporting means,
102 ... Guide plate, 103, 108, 109, 110, 111, 201, 202
... Roller pair, 104 ... Switching guide, 106 ... Paper tray
(Second stack part), 107 ... Paper support, 109a, 109b
... roller, 112 ... leaf spring, 113 ... reversing part, 200 ... transport cassette (lower re-transporting means), 203 ... delivery roller, 20
5 ... Lever, 209 ... Transport guide, 210 ... Passage.

Claims (8)

[Claims] 1. An image forming apparatus capable of recording on both sides of a sheet having a sheet re-conveying path for conveying again to an image recording unit for recording on the second side of a sheet on which recording on the first side has been completed. , An upper re-conveying unit having a sheet re-conveying path from a discharge section at the upper part of the image forming apparatus to a rear section, and a lower re-conveying unit having a sheet re-conveying path below the image forming apparatus. An image forming apparatus capable of recording on both sides of a sheet, wherein the conveying path is formed in a substantially U shape so as to surround an upper portion, a rear portion and a lower portion of the image forming apparatus. 2. An image forming apparatus capable of recording on both sides of a sheet according to claim 1, wherein the upper re-conveying means is detachably provided on the image forming apparatus. 3. The lower re-conveying means can be mounted in a space in which a paper feed cassette for paper feeding, which is detachably provided in the image forming apparatus, is taken out.
An image forming apparatus capable of recording on both sides of the described paper. 4. The upper re-conveying means has a sheet support for temporarily placing a recording sheet on the first side on the upper side, and a second stack for placing the recording sheet on the second side. The image forming apparatus capable of recording on both sides of a sheet according to claim 1, wherein the portions are provided so as to overlap each other. 5. The upper re-conveying means places the recorded paper of the image forming apparatus on the first re-conveying means when the upper re-conveying means is not mounted.
5. The sheet according to claim 1, 2, 3 or 4, characterized in that a transport path for re-transporting a sheet is formed between the stack part of the sheet and the upper re-transporting means when the upper re-transporting means is mounted. Image forming device that can record on both sides. 6. The image forming apparatus capable of recording on both sides of a sheet according to claim 1, wherein the sheet re-conveying path is provided so as to be openable. 7. The upper re-conveying means is provided with a reversing means which is adjacent to the discharging section of the image forming apparatus and which reverses the sheet discharged from the discharging section. An image forming apparatus capable of recording on both sides of a sheet of paper 3, 4, 5, or 6. 8. The upper re-conveying means includes a discharge paper stopper for use in the first stack section, which is a second sheet of the upper re-conveying means.
The image forming apparatus capable of recording on both sides of a sheet according to claim 4, wherein the image forming apparatus is provided so as to be attachable to a stack portion of the sheet.