JP6771982B2 - Image forming device - Google Patents

Description

The present invention relates to an electrophotographic image forming apparatus such as a copier or a laser beam printer that forms an image on a recording material.

Some image forming devices have a mode in which the image forming device prompts the user to read an image of a recording material printed by itself. For example, the user sets the recording material printed by the image forming apparatus on the platen, causes the image forming apparatus to read the image of the recording material, and based on this information, the image forming apparatus forms an image at the time of subsequent printing. Fine-tune the conditions. As a result, the image quality can be improved (Patent Document 1).

JP-A-2010-102239

By the way, it is also conceivable that an image forming apparatus on which the platen is not mounted automatically causes the image forming apparatus to automatically read the image of the recording material printed by itself. In this case, it is conceivable to arrange an image sensor for reading an image inside the image forming apparatus.

As an image sensor for reading an image, an image sensor such as a contact image sensor (CIS) in which elements for converting light into an electric signal are arranged in a row is often used. In many such image sensors, the photoelectric conversion efficiency changes due to the temperature rise, and the image reading accuracy decreases. Therefore, it is not preferable to arrange the image sensor (image reading unit) near a heat source such as a heat fixing unit.

On the other hand, it is preferable that the time required for reading the image is short. If the moving distance of the recording material from the fixing portion to the image sensor is too long, the time from when the recording material passes through the fixing portion until the image sensor reads the image becomes too long. Considering the processing to be performed after reading the image (for example, changing the image forming conditions), it is preferable that the moving distance of the recording material to the image sensor (to be exact, until the image is read) is short. Further, when an image is formed on both sides of the recording material and the image on at least the first surface is read, it is preferable that the moving distance of the recording material from reading the image on the first surface to the start of image formation on the second surface is short.

An object of the present invention is to provide an image forming apparatus capable of reducing heat transfer from a fixing unit to an image reading unit and shortening the time required for image reading.

In the present invention for solving the above-mentioned problems, an image forming portion for forming an unfixed image on a recording material, a fixing portion for fixing an unfixed image formed on the recording material on the recording material, and a recording having been fixed. A discharge unit that discharges the material to the outside of the device, a discharge transport path that guides the recording material from the fixing portion to the discharge portion, and a rear end of the recording material that has passed through the fixing portion are transferred so as to be changed to the tip. An inversion part that inverts the recording material, a double-sided transfer path for guiding the recording material inverted by the inversion part to the image forming part again, and a recording material from a branch point in the middle of the discharge transfer part to the inversion part. An image formed on the recording material is read by an image forming apparatus having a first transport path for guiding the image and a second transport path for guiding the recording material inverted by the reversing portion to the double-sided transport path. A reading unit, a third transport path that guides the recording material inverted by the reversing unit to the reading unit, and a fourth transport path that guides the recording material that has passed through the reading unit to the double-sided transport path. When the surface of the recording material on which the image is first formed is the front surface and the surface opposite to the front surface is the back surface, the third transport path from the inversion portion, the reading portion, and the above The orientation of the front and back of the recording material passing through the double-sided transport path via the fourth transport path is the front and back directions of the recording material passing through the double-sided transport path from the reversing portion via the second transport path. The orientation is the same, and the second transport path is arranged between the reading portion and the fixing portion.

Further, in the present invention, an image forming portion that forms an unfixed image on a recording material, a fixing portion that fixes an unfixed image formed on the recording material to the recording material, and a recording material that has been fixed are discharged to the outside of the apparatus. By the discharge reversing part and the discharge reversing part, which can selectively execute the operation of reversing the recording material and the operation of reversing the recording material so that the rear end of the recording material passing through the fixing portion is changed to the tip and conveyed. It was inverted by the double-sided transport path for guiding the inverted recording material to the image forming portion again, the first transport path for guiding the recording material from the fixing portion to the discharge reversing portion, and the discharge reversing portion. In an image forming apparatus having a second transport path for guiding the recording material to the double-sided transport path, the reading unit for reading the image formed on the recording material and the recording material inverted by the discharge reversing section are read. It has a third transport path that guides the recording material and a fourth transport path that guides the recording material that has passed through the reading unit to the double-sided transport path, and an image is formed first on the surface of the recording material. When the surface facing the surface is the front surface and the surface opposite to the front surface is the back surface, the discharge reversing portion passes through the double-sided transport path via the third transport path, the reading section, and the fourth transport path. The direction of the front and back of the recording material is the same as the direction of the front and back of the recording material that passes from the discharge reversing portion through the second transport path and the double-sided transport path, and the second transport path is the same. It is characterized in that it is arranged between the reading unit and the fixing unit.

According to the present invention, it is possible to provide an image forming apparatus in which heat transfer from a fixing unit to an image reading unit can be reduced and the time required for image reading is short.

Sectional drawing of the image forming apparatus of Example 1 Enlarged view of the upper right part of FIG. Cross-sectional view of the sensor unit (image sensor) Sectional drawing of the image forming apparatus of Example 2 Enlarged view of the upper right part of FIG. Cross-sectional view of the image forming apparatus of Example 3 Enlarged view of the upper right part of FIG. The figure which shows the operation of the transport sensor

(Example 1)
The image forming apparatus of the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 2 is an enlarged view of a part of FIG. The image forming apparatus of Example 1 and other examples described later is a full-color laser beam printer provided with a plurality of photoconductor drums, but is a monochrome image forming apparatus having only one photoconductor drum. It doesn't matter.

(Paper feed section)
FIG. 1 is a cross-sectional view of the image forming apparatus 1. A cassette 2 for accommodating the recording material is retractably housed in the lower portion of the image forming apparatus 1. A cassette feeding unit 3 is arranged near the end of the cassette 2. A manual feed feeding unit 4 is arranged on the right side of the image forming apparatus 1. The cassette feeding unit 3 and the manual feeding unit 4 separate the recording materials one by one and supply them to the resist roller 5. A transport sensor 200a for detecting the passage of the recording material is arranged downstream of the resist roller 5 in the recording material transport direction.

(Transport sensor)
The transport sensor 200a will be described below with reference to FIG. The transport sensor 200a includes a sensor arm 221 arranged so as to project from the transport path 223 and rotatably supported around a shaft support portion 222, and a detection unit 224 for detecting the movement of the sensor arm 221. The sensor arm 221 is held at a solid line position by an urging means (not shown) such as a spring. When the recording material 225 moves in the direction of the solid arrow in FIG. 8 and reaches the transport sensor 200a, the sensor arm 221 is pushed up by the recording material 225 and moves to the position of the broken line in FIG. The detection unit 224 detects the movement of the sensor arm 221 and transmits a signal notifying that the recording material 225 has reached the transport sensor 200a to a control means (not shown). After that, when the recording material 225 further moves and the downstream end 226 of the recording material 225 separates from the sensor arm 221, the sensor arm 221 moves to the position of the solid line in FIG. Here, the end of the recording material 225 facing the downstream side in the transport direction is the front end, and the end facing the upstream side is the rear end. The detection unit 224 detects the movement of the sensor arm 221 and transmits a signal notifying that the recording material 225 has passed the transport sensor 200a to a control means (not shown). The transport sensors 200b and 200c, which will be described later, have the same structure as the transport sensor 200a.

(Image forming part and fixing part)
The image forming apparatus 1 has an image forming unit 6. The image forming unit 6 of this example has four image forming stations 6Y, 6M, 6C, and 6K of yellow, magenta, cyan, and black. The image forming unit 6 is provided with photoconductors 7Y, 7M, 7C, 7K, which are image carriers, and chargers 8Y, 8M, 8C, 8K, which uniformly charge the surface of each photoconductor. Further, a scanner unit 9 that irradiates a laser beam based on image information to form an electrostatic latent image on a photoconductor, and a developing device 10Y, 10M, 10C, 10K that develops by adhering toner to the electrostatic latent image. It is provided. Further, primary transfer portions 12Y, 12M, 12C, and 12K that transfer the toner image on the photoconductor to the electrostatic transfer belt 11 are arranged. The toner image transferred to the transfer belt 11 is transferred to the surface (first surface) of the recording material by the secondary transfer unit 13. After that, the toner image on the recording material is fixed by the fixing unit 14. The fixing portion 14 includes a fixing roller (first rotating body) 14a having a heat source inside and a pressure roller (second rotating body) 14b forming a fixing nip portion that sandwiches and conveys the recording material together with the fixing roller 14a. Have. The recording material is heated while being conveyed by the fixing nip portion. As a result, the unfixed image formed on the recording material is fixed on the recording material. Of the fixing roller (first rotating body) 14a and the pressure roller (second rotating body) 14b, the fixing roller (first rotating body) 14a is in contact with the unfixed image.

(Discharge part and reversing part)
A transport sensor 200b is arranged downstream of the fixing portion 14. When the transport sensor 200b is pushed up by the recording material and located at the position of the dotted line in the drawing, it is detected that the recording material is correctly transported. After that, when the first flapper 15a is located at the position of the solid line in the drawing, the recording material is guided to the discharge roller pair (discharge part) 16 arranged on the upper left side of the fixing part 14. When the first flapper 15a is located at the position of the broken line, the recording material is guided to the switchback roller pair (reversing portion) 17 arranged above the discharge roller pair 16. The switchback roller pair 17 is a roller pair that reverses the recording material so that the rear end of the recording material that has passed through the fixing portion 14 changes to the tip and is conveyed. The discharge roller pair 16 is a roller pair that discharges the fixing-processed recording material to the outside of the apparatus, and the recording material conveyed to the discharge roller pair 16 side is discharged to the recording material loading unit (recording material discharge tray) 18. Reference numeral 19 is a discharge transport path for guiding the recording material from the fixing unit 14 to the discharge unit 16.

(Image reader)
Next, the image reading unit 100 that reads the image of the recording material will be described. The image reading unit 100 is arranged in the image forming apparatus 1 and above the fixing unit 14. The image reading unit 100 has sensor units (image sensors) 101a and 101b for reading an image of a recording material. FIG. 3 is a cross-sectional view and a perspective view of the sensor unit 101b. As shown in FIG. 3, the sensor unit 101b and the sensor unit 101b located at the same position in the recording material transport direction have a reading surface 201 formed of a transparent material such as glass. Further, it has a holder 202, a housing 203, an LED array 204 arranged in the paper width direction, a light receiving element 205, and a rod lens 206. The holder 202 is a resin component that holds the LED array 204, the light receiving element 205, and the rod lens 206. The housing 203 is made of aluminum. The recording material is conveyed while its read surface is in contact with the reading surface 201. Further, the light emitted from the LED array 204 is reflected by the surface of the recording material, the reflected light is collected by the rod lens 206, and an image is formed on the light receiving element 205. The light receiving element 205 converts the input light into a voltage to convert the image information of the recording material into an electric signal to obtain image data. Since the sensor unit 101a is only the sensor unit 101b arranged upside down, detailed description thereof will be omitted.

(Print on the back of the recording material)
When printing is performed on the back surface (second surface) of the recording material, the first flapper 15a is moved to the position of the broken line and the second flapper 15b is moved to the position of the solid line. As a result, a first transport path 21 for guiding the recording material from the first branch point 20 in the middle of the discharge transport path 19 to the switchback roller pair 17 is formed, and the recording material is transferred from the fixing portion 14 to the switchback roller pair 17. Transport. After that, by rotating the switchback roller pair 17 in the direction of feeding the recording material to the left in FIG. 2, the recording material is conveyed until the rear end of the recording material passes through the transfer guide tip 28 of FIG. After that, by moving the first flapper 15a to the position of the solid line, a second transport path 22 for guiding the recording material from the switchback roller pair 17 to the double-sided transport path 27 is formed. The second transport path 22 is a transport path that guides the recording material inverted by the switchback roller pair 17 to the double-sided transport path 27. The timing of moving the first flapper 15a and the second flapper 15b may be after a predetermined time has elapsed from the rear end of the recording material passing through the transport sensor 200b. After that, the switchback roller pair 17 is temporarily stopped, and then the recording material is rotated in the direction of feeding to the right in FIG. 2, so that the recording material is transported to the double-sided transport path 27 via the second transport path 22. To do. Here, the second transport path 22 is formed so as to pass through the upper part of the fixing portion 14. A transport sensor 200c is arranged in the middle of the double-sided transport path 27, and detects that the recording material is correctly transported by the same mechanism as the transport sensor 200a described above. After the recording material is conveyed to the double-sided transfer path 27, the recording material is again conveyed to the resist roller 5 via the double-sided transfer rollers 25 and 26. After that, the recording material is conveyed to the discharge roller pair 16 via the secondary transfer unit 13, the fixing unit 14, and the discharge transfer path 19, and is discharged to the recording material loading unit 18.

(Reading the image (printed image) of the recording material)
When the image reading unit 100 reads the image of the recording material on which the toner image is fixed by the fixing unit 14, the recording material is conveyed to the switchback roller pair 17 via the first conveying path 21. Then, by rotating the switchback roller pair 17 in the direction of feeding the recording material to the left in FIG. 2, the recording material is conveyed until the rear end of the recording material passes the point 29 on the transfer guide shown in FIG. To do. After that, by moving the first flapper 15a to the position of the solid line and the second flapper 15b to the position of the broken line, the third transport path 23 for transporting the recording material from the switchback roller pair 17 to the image reading unit 100. To form.

Here, in the sensor units 101a and 101b of the image reading unit 100, the surfaces for reading images (plane 201 in FIG. 3) face each other inside the image forming apparatus 1 and above the second transport path 22. Arranged. As the sensor unit, CIS (contact image sensor) or the like can be used. By arranging the two sensor units 101a and 101b so as to face each other, it is possible to read the images printed on both sides of the recording material that have passed between the two sensor units at once. If it is not necessary to read the images on both sides of the recording material at one time, only one sensor unit may be arranged. However, when only one sensor unit is used, the sensor unit 101a is removed and the sensor unit 101b is left. The sensor unit 101b is a unit provided on the side of the two surfaces of the recording material that has been inverted by the reversing portion 17 and that faces the surface of the recording material that has come into contact with the first rotating body 14a immediately before. Therefore, if at least the sensor unit 101b of the two sensor units is provided, the time from when the recording material passes through the fixing portion 14 until the sensor unit 101b reads the image can be shortened. Therefore, the time required for reading the image can be shortened.

Further, the timing of moving the first flapper 15a and the second flapper 15b is such that the rear end of the recording material passes through the transport sensor 200d arranged between the second flapper 15b and the switchback roller pair 17. It may be after a predetermined time has elapsed from. The mechanism of the transport sensor 200d is the same as that of the transport sensor 200a described above. After that, the switchback roller pair 17 is temporarily stopped, and then the recording material is rotated in the direction of feeding to the right in FIG. 2, so that the recording material is transferred to the third transport path 23, the image reading unit 100, and the fourth transport. It is transported to the double-sided transport path 27 via the path 24. The fourth transport path 24 is formed in the upper part of the second transport path 22. The image reading unit 100 reads an image of the recording material being conveyed. The read image information is recorded or feature-extracted by an image information processing unit (not shown), and the information obtained from these processes can be used to evaluate a printed image and adjust image formation conditions. Further, the read image information can be stored in an electronic recording unit such as a memory (not shown) arranged inside the apparatus or a computer (not shown) on the network.

In the image forming apparatus 1 of this embodiment, the second transport path 22 is arranged between the image reading unit 100 and the fixing unit 14. In other words, the second transport path 22 is arranged between the third and fourth transport paths 23, 24 and the fixing portion 14. As a result, a part of the heat generated in the fixing unit 14 is insulated by the air existing in the second transport path 22, so that the temperature rise of the image reading unit 100 can be suppressed.

Further, in double-sided printing, the surface of the recording material on which the image is first formed is the front surface, and the surface opposite to the front surface is the back surface. In the device of this example, the front and back directions of the recording material passing through the double-sided transport path 27 from the reversing section 17 via the third transport path 23, the reading section 100, and the fourth transport path 24 are the reversing section 17. It is the same as the front and back directions of the recording material passing through the double-sided transport path 27 via the second transport path 22. Specifically, of the two surfaces of the recording material passing through the second transport path 22, the surface of the recording material that has just come into contact with the first rotating body 14a is the surface facing the lower side of FIG. Further, of the two surfaces of the recording material passing through the third and fourth transport paths 23 and 24, the surface of the recording material that has just come into contact with the first rotating body 14a is the surface facing downward in FIG. is there. That is, the recording material passing through the double-sided transport path 27 from the reversing section 17 via the third transport path 23, the reading section 100, and the fourth transport path 24 is transported to the image forming section 6 again. It is not necessary to reverse the front and back. Therefore, as with the recording material that has passed through the second transport path 22, an image can be immediately formed on the second surface, and the time required to read the images on both sides can be shortened.

As described above, the apparatus of this example can reduce the heat transfer from the fixing unit to the image reading unit, and can also shorten the time required for image reading.

(Example 2)
The image forming apparatus of the second embodiment will be described with reference to FIGS. 4 and 5. The description of the portion overlapping with the first embodiment will be omitted.

The image forming apparatus 1 in this embodiment is provided with a discharge reversing roller pair (discharge reversing portion) 31 instead of the discharge roller pair 16 and the switchback roller pair 17 in the first embodiment.

When the recording material on which the toner image is fixed by the fixing portion 14 is discharged to the outside of the apparatus, the first flapper 15a and the second flapper 15b are moved to the positions of the solid lines. As a result, a first transport path 21 for transporting the recording material from the fixing portion 14 to the discharge reversing roller pair 31 is formed. After that, the recording material is discharged to the recording material loading unit 18 by rotating the discharge reversing roller pair 31 in the direction of transporting the recording material to the left in FIG. Here, a transport path for transporting the recording material discharged from the discharge reversing roller pair 31 to a post-processing device (not shown) arranged in the vicinity of the image forming device 1 is formed, and the recording material is sorted, stapled, and sorted. It may be possible to carry out post-processing such as.

(Print on the back of the recording material)
On the other hand, when printing is performed on the back surface of the recording material, the recording material is conveyed from the fixing portion 14 to the discharge reversing roller pair 31 via the first conveying path 21. After that, by rotating the discharge reversing roller pair 31 so as to feed the recording material to the left in FIG. 5, the recording material is conveyed until the rear end of the recording material passes through the transfer guide tip 28 in FIG. After that, by moving the first flapper 15a to the position of the broken line and the second flapper 15b to the position of the solid line, the second transport path 22 for transporting the recording material from the discharge reversing roller pair 31 to the double-sided transport path 27. To form. The timing of moving the first flapper 15a and the second flapper 15b may be the same as in the first embodiment. After that, by temporarily stopping the discharge reversing roller pair 31 and then rotating the recording material in the direction of feeding to the right in FIG. 5, the recording material is transported to the double-sided transport path 27 via the second transport path 22. To do.

(Reading the image (printed image) of the recording material)
When the image of the recording material on which the toner image is fixed is read by the fixing unit 14, the recording material is conveyed to the discharge reversing roller pair 31 via the first conveying path 21. Then, by rotating the discharge reversing roller pair 31 in the direction of feeding the recording material to the left in FIG. 5, the recording material is conveyed until the rear end of the recording material passes the point 29 on the transfer guide shown in FIG. To do. After that, by moving the first flapper 15a to the position of the solid line and the second flapper 15b to the position of the broken line, the third transport path 23 for transporting the recording material from the discharge reversing roller pair 31 to the image reading unit 100. To form. The timing of moving the first flapper 15a and the second flapper 15b may be the same as in the first embodiment. After that, the discharge reversing roller pair 31 is temporarily stopped, and then the recording material is rotated in the direction of feeding to the right in FIG. 5, so that the recording material is transferred to the third transport path 23, the image reading unit 100, and the fourth transport. It is transported to the double-sided transport path 27 via the path 24. The image reading unit 100 reads an image of the recording material being conveyed.

In the image forming apparatus 1 of this embodiment, as in the first embodiment, the second transport path 22 is arranged between the image reading unit 100 and the fixing unit 14. In other words, the second transport path 22 is arranged between the third and fourth transport paths 23, 24 and the fixing portion 14. As a result, a part of the heat generated in the fixing unit 14 is insulated by the air existing in the second transport path 22, so that the temperature rise of the image reading unit 100 can be suppressed.

Further, in double-sided printing, the surface of the recording material on which the image is first formed is the front surface, and the surface opposite to the front surface is the back surface. In the device of this example, the front and back directions of the recording material passing through the double-sided transport path 27 from the discharge reversing section 31 to the third transport path 23, the reading section 100, and the fourth transport path 24 are reversed. It is the same as the front and back directions of the recording material that passes from the section 31 to the double-sided transport path 27 via the second transport path 22. Therefore, as with the recording material that has passed through the second transport path 22, an image can be immediately formed on the second surface, and the time required to read the images on both sides can be shortened.

As described above, the apparatus of this example can also reduce the heat transfer from the fixing unit to the image reading unit and shorten the time required for image reading.

In the case of this example as well, if at least the sensor unit 101b of the two sensor units is provided, the time from when the recording material passes through the fixing portion 14 until the sensor unit 101b reads the image can be shortened.

(Example 3)
The image forming apparatus of the third embodiment will be described with reference to FIGS. 6 and 7. The description of the portion overlapping with the first embodiment will be omitted.

The image forming apparatus 1 in this embodiment has an aftertreatment apparatus 301 arranged in the upper right portion thereof. The post-processing device 301 is provided with a recording material evacuation path 302, a post-processing discharge roller pair 303, and a post-processing recording material loading unit 304. The recording material evacuation path 302 is connected to the switchback roller pair 17 of the image forming apparatus 1, and temporarily stores the recording material partially discharged from the switchback roller pair 17. The aftertreatment device 301 in this embodiment has only a function of separating and discharging the recording material by adding a recording material loading unit, but has a function of stapling and sorting the recording material. It may be.

When the recording material on which the toner image is fixed by the fixing portion 14 is conveyed to the post-processing discharge roller pair 303, the first flapper 15a is moved to the position of the solid line, and the post-processing transfer flapper 44 is moved to the position of the broken line. As a result, the post-processing transfer path 42 that transfers the recording material from the second branch point 41 between the first branch point 20 on the discharge transfer path 19 and the discharge roller pair 16 to the post-processing transfer roller pair 43 is provided. Form. After that, the recording material is transported to the post-treatment discharge roller pair 303 via the second post-treatment discharge transport path 305, and is discharged to the post-treatment recording material loading unit 304. A transport sensor 200e is arranged between the post-processing transfer flapper 44 and the post-processing transfer roller pair 43, and the recording material is correctly conveyed by the same mechanism as the transfer sensor 200a described in the first embodiment. Is detected. In this embodiment, the post-processing transfer roller pair 43 is arranged inside the image forming apparatus 1, but may be arranged inside the after-processing apparatus 301. Further, in order to transport the recording material to the post-processing apparatus having a plurality of transport paths other than the recording material evacuation passage 302, a plurality of post-treatment transport paths 42, a post-treatment transport roller pair 43, and a plurality of post-treatment transport flappers 44 are arranged. You may.

As in this example, even if the image forming apparatus is provided with a transport unit that transports the recording material after printing to a post-processing device that performs post-processing such as stapling and sorting, the fixing unit to the image reading unit. The heat transfer can be reduced, and the time required for reading the image can be shortened.

14 Fixing part 16 Discharge roller pair (Discharge part)
17 Switchback roller pair (reversing part)
21 1st transport path 22 2nd transport path 23 3rd transport path 24 4th transport path 27 Double-sided transport path 31 Discharge reversing roller pair (discharge reversing part)
100 Image reader

Claims (5)

An image forming part that forms an unfixed image on the recording material,
A fixing part that fixes the unfixed image formed on the recording material to the recording material,
A discharge unit that discharges the fixing-processed recording material to the outside of the device,
A discharge transport path that guides the recording material from the fixing part to the discharge part,
An inversion part that inverts the recording material so that the rear end of the recording material that has passed through the fixing part changes to the tip and is conveyed.
A double-sided transport path for guiding the recording material inverted by the inversion portion to the image forming portion again, and
A first transport path that guides the recording material from a branch point in the middle of the discharge transport path to the reversing portion, and
A second transport path that guides the recording material inverted by the reversing portion to the double-sided transport path, and
In the image forming apparatus having
A reading unit that reads the image formed on the recording material,
A third transport path that guides the recording material inverted by the inversion unit to the reading unit, and
A fourth transport path that guides the recording material that has passed through the reading unit to the double-sided transport path, and
Have,
Assuming that the surface of the recording material on which the image is first formed is the front surface and the surface opposite to the front surface is the back surface, the third transport path, the reading portion, and the fourth transport from the reversing portion are used. The direction of the front and back of the recording material passing through the double-sided transport path via the road is the same as the direction of the front and back of the recording material passing through the double-sided transport path from the reversing portion via the second transport path. Yes,
The second transport path is arranged between the reading unit and the fixing unit.
An image forming apparatus characterized in that. The fixing portion includes a first rotating body that comes into contact with an unfixed image on the recording material, and a second rotating body that forms a fixing nip portion that sandwiches and conveys the recording material together with the first rotating body.
The claim is characterized in that the reading portion is provided on the side of the two surfaces of the recording material inverted by the reversing portion, which faces the surface of the recording material that has come into contact with the first rotating body immediately before. Item 1. The image forming apparatus according to item 1. An image forming part that forms an unfixed image on the recording material,
A fixing part that fixes the unfixed image formed on the recording material to the recording material,
It is possible to selectively execute the operation of discharging the recording material that has been fixed to the outside of the device and the operation of reversing the recording material so that the rear end of the recording material that has passed through the fixing portion is changed to the tip and conveyed. Emission reversing part and
A double-sided transport path for guiding the recording material inverted by the discharge inversion unit to the image forming unit again, and
A first transport path for guiding the recording material from the fixing portion to the discharge reversing portion,
A second transport path that guides the recording material inverted by the discharge reversing section to the double-sided transport path, and
In the image forming apparatus having
A reading unit that reads the image formed on the recording material,
A third transport path that guides the recording material inverted by the discharge reversing unit to the reading unit, and
A fourth transport path that guides the recording material that has passed through the reading unit to the double-sided transport path, and
Have,
Assuming that the surface of the recording material on which the image is first formed is the front surface and the surface opposite to the front surface is the back surface, the third transport path, the reading portion, and the fourth The orientation of the front and back of the recording material passing through the double-sided transport path via the transport path is the direction of the front and back of the recording material passing through the double-sided transport path from the discharge reversing portion via the second transport path. Is the same
The second transport path is arranged between the reading unit and the fixing unit.
An image forming apparatus characterized in that. The fixing portion includes a first rotating body that comes into contact with an unfixed image on the recording material, and a second rotating body that forms a fixing nip portion that sandwiches and conveys the recording material together with the first rotating body.
The reading unit is provided on the side of the two surfaces of the recording material inverted by the discharge reversing unit, which faces the surface of the recording material that has come into contact with the first rotating body immediately before. The image forming apparatus according to claim 3. When reading an image of the recording material, the apparatus conveys the recording material to the front of the double-sided transport path via the third transport path, the reading unit, and the fourth transport path, and the recording material The image forming apparatus according to any one of claims 1 to 4, wherein when the image is not read, the recording material is transported to the double-sided transport path via the second transport path.

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