JP3005637U - Image forming device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide an image forming apparatus capable of preventing the deterioration of the quality of a recorded image on a recording sheet and the occurrence of a paper jam as much as possible. Constitution: In an image forming apparatus 1 configured to form images on both sides of a sheet of recording paper 9, to a switchback means 30 for reversing the traveling direction of the recording paper 9 and reversing the upper and lower surfaces of the recording paper 9. The curving direction of the curving portion 11a formed at the terminal end portion 11b of the first paper guide chute 11 for guiding the recording paper and the recording paper whose upper and lower surfaces are reversed by the switchback means 30 are guided again to the image forming means 6. The bending portion 12b formed on the starting end portion 12a of the second sheet guide chute 12 is formed so as to be in the same direction as the sheet conveying direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of an image forming apparatus that forms an image on both sides of a sheet of recording paper.

[0002]

[Prior art]

 Generally, in an image forming apparatus such as a copying machine or a laser printer, after an image is formed on one side of a sheet-like recording sheet, the sheet is reversed and conveyed to the image recording process again, and then the other side of the sheet. An image forming apparatus that forms an image again has been proposed.

Conventionally, as an image forming apparatus for forming an image on both sides of such a sheet-like recording paper, there is one described in JP-A-2-255476.

As shown in FIG. 1 of Japanese Patent Application Laid-Open No. 2-255476, when an image is formed on both sides of a sheet, an electrostatic recording means such as a photosensitive drum is used. After the image is formed on one side of the paper, the image-recorded paper is reversed by the switchback means arranged above the paper ejection tray to reverse its direction of travel, and the inverted image is recorded. The sheet is guided again to the electrostatic recording means to form an image on the other side of the recording sheet, and then the sheet with the image formed on both sides is discharged onto a discharge tray.

Further, conventionally, as shown in FIG. 4 of Japanese Patent Laid-Open No. 2-110083, the direction of travel of an image-recorded sheet having an image formed on one side of the recording sheet is reversed to form a recording surface. There is also a device in which a switchback means for reversing the electrostatic recording means is provided on the bottom side of the apparatus main body.

[0006]

By the way, among the above-mentioned conventional examples, the one disclosed in Japanese Patent Laid-Open No. 2-255476 discloses that the switchback means is disposed above the paper discharge tray and the image-recorded paper is used. Since the majority of the paper is temporarily exposed to the outside of the main body when the traveling direction is reversed to reverse the paper, the operator may accidentally take out the recording paper exposed to the outside of the equipment. is there. Further, in the one disclosed in Japanese Patent Application Laid-Open No. 2-255476, most of the image-recorded paper having an image formed on one side thereof is exposed to the outside of the apparatus, so that the recording paper touches the outside air to collect dust. When the image is formed on the other side surface of the recording sheet due to the adsorbed dust and thus the adsorbed dust, the formation quality of the image may be significantly deteriorated.

On the other hand, in the one described in FIG. 4 of Japanese Patent Laid-Open No. 2-110083, the switchback means is arranged on the bottom side of the apparatus, and thereby the direction in which the image-recorded paper is reversed is advanced. Since the recording paper is not exposed to the outside of the apparatus when the sheet is reversed, the above-mentioned problem does not occur. However, in the one described in FIG. The end portion of the first paper guide chute for guiding the image-recorded paper to the provided switchback means has a curved portion that is curved to the right side with respect to the traveling direction thereof, and by the switchback means, The starting end of the second paper guide chute that guides the paper whose traveling direction is reversed to the electrostatic recording means again has a curved portion that is curved to the left with respect to the traveling direction. That is, the bending direction of the bending portion formed at the end portion of the first paper guide chute and the bending direction of the bending portion formed at the start end portion of the second paper guiding chute are opposite to the paper transport direction. Is.

For this reason, the recording paper whose traveling direction is reversed by the switchback means is bent in one direction by the curved portion formed at the terminal end of the first paper guide chute, and then further moved to the second paper guide chute. The curved portion formed at the beginning end of the sheet will be bent again in the same direction.

Therefore, according to the one disclosed in Japanese Patent Laid-Open No. 2-110383, the recording paper in the one-sided bent posture is guided again to the electrostatic recording means as it is. Therefore, a paper jam is likely to occur, and an image is formed on a curved recording sheet, so that the quality of a recorded image formed on the other side surface of the recording sheet may be significantly deteriorated.

In view of the above-mentioned circumstances, the present invention aims to provide an image forming apparatus that prevents deterioration of the quality of a recorded image on a recording sheet and occurrence of a paper jam as much as possible.

[0011]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, according to the present invention, an image forming means is provided in the apparatus main body and forms an image on one side surface of a sheet-like recording sheet, and an image is formed on one side surface by the image forming means. A first sheet guide sheet for guiding the recording sheet to the bottom side of the apparatus main body and a reverse direction of the recording sheet arranged via the first sheet guide chute disposed on the bottom surface of the apparatus main body. And a second paper guide chute for guiding the recording paper whose upper and lower surfaces are reversed by the switchback means to the image forming means again. In the image forming apparatus configured to form the images on both sides of the sheet-shaped recording sheet, the first sheet guide chute and the second sheet guide chute have a trailing end portion and a trailing end portion, respectively. This The curving portion is formed, and the curving direction of the curving portion formed at the end portion of the first paper guide chute and the curving direction of the curving portion formed at the start end portion of the second paper guide chute are set in the paper conveyance direction. The direction is the same.

[0012]

[Action]

 According to the above-described image forming apparatus, the curving direction of the curving portion of the first paper guide chute terminal portion that guides the recording paper on one side of which the image is formed to the switchback means and the reverse direction from the switchback means to the image forming means. Since the curving direction of the second paper guiding chute starting end portion of the second paper guiding chute is the same as the paper conveying direction, the curving portion of the first paper guiding chute is bent in one direction. The recording sheet is bent and corrected in the other direction by the curved portion of the second sheet guide chute, so that the recording sheet having no curve is conveyed again to the image forming means.

[0013]

【Example】

 An embodiment of the image forming apparatus according to the present invention will be described in detail below.

FIG. 1 is a conceptual diagram of an image forming apparatus 1 according to the present invention.

The image forming apparatus 1 includes an apparatus main body 2 including a housing, a paper discharge unit 3 detachably attached to the right side of the apparatus main body 2, and a bottom surface of the apparatus main body 2 detachably attached. And a switchback unit 4 which is configured as a switch.

The above-described paper discharge unit 3 and switchback unit 4 are prepared as options, and are not used in a normal image forming process, that is, when an image is formed on only one side of the recording paper.

On the other hand, in the apparatus main body 2, an electrostatic recording type image forming unit 6 composed of a photoconductor 5 and the like, a fixing unit 8 composed of a fixing roller 7 and the like, and an electrostatic recording system. Each of the main constituent elements and the like that constitute it are arranged, and a paper cassette 10 accommodating and accommodating sheet-like recording paper 9 is detachably attached to the bottom thereof.

On the other hand, in the above-mentioned paper discharge unit 3, the recording paper having an image formed on one side by the image forming means 6 is guided to the switchback unit 4 arranged on the bottom side of the apparatus main body 2. The first paper guide chute 11 is provided, and the switchback unit 4 is provided with a second paper guide chute 12 that guides the recording paper reversed by the switchback unit 4 to the image forming unit 6 again. .

Next, the operation of the image forming apparatus 1 described above will be described, and the configuration will be described in more detail.

First, the image forming process in the single-sided recording mode for forming an image on only one side of the recording paper will be described.

When one sheet of recording paper 9 is fed from the uppermost surface of the paper cassette 10 by the feed roller 20, the recording paper 9 is conveyed to the image forming means 6 along the arrow of the paper path 21 shown by the chain double-dashed line. An image is formed on one side of the recording sheet by the image forming means 6. A plurality of transport rollers 22 are provided in the middle of the paper path 21 described above.

When an image is formed on one side of the recording paper by the image forming means 6, the recording paper is then conveyed to the fixing means 8 and the image is fixed there. After the image is fixed, the recording sheet on which the image is formed on one side surface is then conveyed to the sheet ejection unit 3 via the ejection roller 23.

On the other hand, in the paper discharge section 3, the first paper guide chute 11 and the first paper guide chute 11 are branched from the starting end of the first paper guide chute 11, and the recorded paper is discharged from the paper discharge outlet 24. A third paper guide chute 25 for guiding the first recording paper to the first and third recording paper guide chutes 25 is provided at the branch point between the first and third paper discharge chutes 11 and 25. A first switching claw 26 that guides one of the three sheet discharge chutes 11 and 25 is provided.

In the single-sided recording mode in which an image is formed on only one side surface, the first switching claw 26 immediately guides the recorded sheet to the third sheet ejection chute 25 as shown in FIG. Therefore, the recording paper on which an image is formed only on one side is guided to the third paper discharge chute 25 by rotating counterclockwise by a predetermined angle.

The recording paper guided to the third paper discharge chute 25 is then discharged by a discharge roller 27 onto a paper discharge tray 28 arranged on the side of the paper discharge unit 4 as indicated by an arrow, and above it. Placed on.

Next, the image forming process in the double-sided recording mode for forming images on both sides of the recording paper will be described.

The recording paper is fed from the paper cassette 10 by the feed roller 20, the image is formed on one side by the image forming means 6, and the recording paper on which the image is fixed by the fixing means 8 is discharged to the paper discharge section 3 via the discharge roller 23. When guided, this time, as shown in FIG. 2, the first switching claw 26 rotates clockwise by a predetermined angle, and the recording paper on which an image is formed only on one side is changed to the first paper. Guide into the discharge chute 11.

The recording sheet guided in the first sheet discharging chute 11 is then conveyed by the conveying roller 29, and the curved portion 11 a formed at the end portion 11 b of the first sheet discharging chute 11 is conveyed. And is guided to the switchback unit 4. At that time, the recording paper is guided into the switchback unit 4 while being bent in one direction by the curved portion 11a of the first paper discharge chute 11 which is curved to the right along the traveling direction.

The reason why the curved portion 11a is formed on the first sheet discharge chute 11 is to set the height of the entire apparatus 1 low and to downsize the apparatus 1.

On the other hand, the switchback means 30 provided in the switchback unit 4 has a chute 31 on one side of which an image is formed and which temporarily holds a recording sheet, and a traveling direction of the temporarily held recording sheet. The recording paper, which is composed of a switchback roller 32 that can be rotated in the reverse direction and that can be rotated in the reverse direction, reverses the traveling direction and reverses the recording paper. It is guided again to the image forming means 6 of the apparatus main body 2 via.

On the other hand, a second switching claw 33 is arranged between the starting end portion 12a of the second sheet guide chute 12 and the rear end portion 11b of the first sheet discharging chute 11.

The second switching claw 33 guides the recording paper guided through the first paper discharge chute 11 to the temporary holding chute 31 and switches the recording paper guided by the holding chute 31. After backing, the second paper guide chute 12 is guided. As shown in FIG. 2, when the recording paper conveyed through the first paper discharge chute 11 is guided into the temporary holding chute 31, it is reversed. The second paper guide chute 12 is rotated clockwise by a predetermined angle to close the starting end 12a side of the second paper guide chute 12.

Therefore, as shown in FIG. 2, the recording sheet guided to the switchback unit 4 by the first sheet discharging chute 11 is guided to the temporary holding chute 31 side by the second switching claw 33, and further rotates normally. The whole of the switchback roller 32 is housed in the temporary storage chute 31. It should be noted that the switchback roller 32 maintains the posture of holding the trailing edge of the recording sheet guided in the retaining chute 31 even when the recording sheet is temporarily held.

Next, when it is detected that the recording paper is temporarily held in the temporarily holding chute 31, the second switching claw 33 rotates clockwise by a predetermined rotation angle as shown in FIG. The switchback roller 32 is rotated in the reverse direction, and the rear end of the recording sheet temporarily held in the temporary holding chute 31 is conveyed in the reverse direction with the trailing edge of the recording sheet as the leading end. The second paper guide chute 12 disposed on the lower surface of the temporary holding chute 31 is guided to the starting end 12a.

In order to set the height of the switchback portion 4 at the starting end portion 12a of the second paper guide chute 12 to be as thin as possible, the curving portion 12b curved to the right with respect to the recording paper conveyance direction. The recording paper guided in the second paper guide chute 12 is conveyed to the paper path 34 while being bent in the other direction by the second paper discharge chute 12 having the curved portion 12b. Further, the sheet path 34 in the apparatus main body 2 is again guided through the sheet path 34. A plurality of transport rollers 22 for transporting the recording paper are provided in the middle of the paper path 34.

As described above, since the recording paper conveyed again to the image forming means 6 via the switchback means 30 of the switchback unit 4 and the second paper discharge chute 12 has its upper and lower sides inverted, this time. An image is formed on the other side surface of the recording paper by the image forming means 6, and is conveyed to the fixing means 8 where the image on the other side surface is fixed. After that, the recording paper on both sides of which images are formed is guided into the paper discharge section 3 via the discharge roller 23 as shown in FIG.

On the other hand, when the recording paper on which images are formed on both sides is guided into the paper discharge section 3, the first switching claw 26 guides the recorded paper to the third paper discharge chute 25 this time. Since the recording paper is rotated counterclockwise by a predetermined angle, the recording paper on both sides of which images are formed is guided into the third paper discharge chute 25. Then, the recording sheet guided to the third sheet discharging shoot 25 is discharged to the outside by the discharging roller 27 as shown by an arrow, and then placed on the discharging tray 28.

By the way, according to the apparatus 1 described above, the terminal end portion 11b of the first sheet guide chute 11 and the starting end portion 12a (FIG. 2) of the second sheet guide chute 12 of the apparatus 1 respectively. In order to achieve miniaturization, the curved portions 11a and 12b are formed, and only the curved direction of the curved portion 11a formed on the first paper guide chute 11 and the curved direction formed on the second paper guide chute 12 are formed. Since the curved direction of the portion 12b is formed to be the same direction as the sheet conveying direction, the device 1 according to the present invention has the following actions.

That is, as shown in FIG. 5 which is an enlarged view of the main part of FIG. 2, the recording paper 9 guided in the first paper discharge chute 11 is formed at the end portion 11 b of the first paper discharge chute 11. While passing through the formed curved portion 11a and being guided into the temporary holding chute 31 of the switchback portion 4, the curved portion 11a bends in one direction and transforms into a curved posture as shown in FIG.

On the other hand, when the recording sheet 9 in the deformed posture as shown in FIG. 6 is guided into the second sheet discharge chute 12 as shown in FIG. 7 which is an enlarged view of the main part of FIG. The folded recording sheet 9 receives a bending force in a direction opposite to the folding direction shown in FIG. 6 while passing through the curved portion 12b formed at the starting end 12a of the second sheet discharging chute 12. The recording paper 9 after passing the second paper ejection chute 12 is corrected and maintains a flat posture as shown in FIG. 8. Therefore, the recording paper 9 after passing the second paper ejection chute 12 is It is possible to avoid the occurrence of paper jam for 9 and the deterioration of the quality of the recorded image by the image forming means 6.

[0041]

[Effect of device]

 As described above, in the image forming apparatus of the present invention, the bending direction of the bending portion formed at the end portion of the first paper guide chute for guiding the recording paper to the switchback means and the image from the switchback means. Since the curving direction of the curving portion formed at the starting end of the second paper guide for guiding the reversed recording paper to the forming means is the same as the conveying direction of the paper, the curving portion of the first paper guiding chute is more effective. The recording paper which is bent in the direction and deformed in posture is bent in the opposite direction by the curved portion of the second paper guide chute and is corrected, and the recording paper in which the posture is not deformed is conveyed again to the image forming means. We propose a compact and stable image forming device that reduces the quality of recorded images on recording paper and prevents paper jams during paper transportation as much as possible. It can be.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an image forming apparatus according to the present invention.

FIG. 2 is a conceptual diagram showing the operation of the image forming apparatus according to the present invention.

FIG. 3 is a conceptual diagram showing the operation of the image forming apparatus according to the present invention.

FIG. 4 is a conceptual diagram showing the operation of the image forming apparatus according to the present invention.

5 is an enlarged view of a main part of FIG.

FIG. 6 is an enlarged view of recording paper.

FIG. 7 is an enlarged view of a main part of FIG.

FIG. 8 is an enlarged view of a recording sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image forming device 2 ... Device body 6 ... Image forming means 9 ... Recording paper 11 ... First paper guide chute 11a ... Curved part 11b ... End part 12 ... Second paper guide chute 12a ... Start end part 12b ... Curved part 30 ... Switchback means

Claims (1)

[Scope of utility model registration request] 1. An image forming means for forming an image on one side surface of a sheet-like recording sheet, which is disposed in the apparatus main body, and a recording sheet having an image formed on the one side surface by the image forming means. And a first paper guide chute that guides the recording paper to the side, and reverses the traveling direction of the recording paper that is disposed on the bottom surface of the apparatus main body and guided through the first paper guide chute so that the upper and lower faces of the recording paper It has at least a switchback means for reversing and a second paper guide chute for guiding the recording paper whose upper and lower surfaces are reversed by the switchback means to the image forming means again. In an image forming apparatus configured to form an image, a curved portion is formed at each of a terminal end portion of the first sheet guide chute and a starting end portion of the second sheet guide chute, and the first sheet guide chute is formed. The bending direction of the bending portion formed at the terminal end of the sheet guiding chute and the bending direction of the bending portion formed at the starting end of the second sheet guiding chute are set in the same direction with respect to the sheet conveying direction. An image forming apparatus characterized by the above.