JP6926424B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus and a recording medium conveying apparatus.

In Patent Document 1, the light emitted from the CIS is reflected by a high-reflectivity object and a recording medium, and the photoelectric conversion element pixel capable of receiving more reflected light than the threshold value is regarded as no recording member, and the photoelectric conversion element pixel that receives less light is excluded. There is disclosed an edge detection device having a recording member.

Patent Document 2 detects and corrects how much the left edge of the electrostatic recording paper deviates from the first pass or how much the electrostatic recording paper expands and contracts in a direction perpendicular to the transport direction. A color image recording device that sends the image data including the above to the recording driver is disclosed.

In Patent Document 3, a transfer paper position detection signal is output to a timing control circuit, the detection signal is taken into the timing control circuit, and every time the transfer paper is conveyed by 1 mm by the laser writing timing signal, the laser writing position in the main scanning direction is determined. An image forming apparatus for performing correction is disclosed.

Japanese Unexamined Patent Publication No. 2012-198073 Japanese Unexamined Patent Publication No. 3-219271 Japanese Unexamined Patent Publication No. 9-219776

The image forming apparatus or the like may be provided with a detection unit that detects the side side of the recording medium and a circuit board that processes information from the detection unit.
Here, if the circuit board is provided on the side opposite to the side where the detection unit is provided by sandwiching the transportation path, the electric wire connecting the detection unit and the circuit board will be installed in the vicinity of the transportation path. .. In this case, for example, when the recording medium guide member located beside the transport path is moved to open a part of the transport path, the electric wire makes it easier to regulate the movement of the recording medium guide member, and the transport path of the transport path. It becomes difficult to perform work on the transport path such as cleaning.
An object of the present invention is to make it easier to work on the transport path as compared with the case where the circuit board is provided on the side opposite to the side where the detection unit is provided across the transport path.

The invention according to claim 1 is provided on one side of a transport path through which the recording medium is conveyed, an image forming unit that forms an image on the recording medium, and the transport path, and is conveyed through the transport path. A detection unit that detects a side side of the recording medium along the recording medium transport direction, a circuit board provided on one side of the transport path and processing information from the detection unit, and a portion facing the detection unit. The pressing means for pressing the located recording medium against the guide member located on the side of the transport path is provided, and the pressing means provides the guide for the recording medium on which the image forming unit has not formed an image. It is an image forming apparatus that does not press against a member.
The invention according to claim 2 is provided on one side of a transport path through which the recording medium is conveyed, an image forming unit that forms an image on the recording medium, and the transport path, and is conveyed through the transport path. A detection unit that detects a side side of the recording medium along the recording medium transport direction, a circuit board provided on one side of the transport path and processing information from the detection unit, and a portion facing the detection unit. The detection unit is configured to be capable of detecting an image formed on the recording medium, and the pressing means is provided with a pressing means for pressing the located recording medium against a guide member located on the side of the transport path. An image forming apparatus that releases the pressing of the recording medium against the guide member when the image formed on the recording medium is detected by the detection unit.

According to the invention of claim 1, the transport resistance received by the recording medium on which the image is not formed is reduced as compared with the case where the pressing means is pressed against the guide member against the recording medium on which the image is not formed. Can be done.
According to the invention of claim 2 , the recording medium to be pressed is compared with the case where the pressing means continues to press the recording medium to the guide member even after the image formed on the recording medium is detected by the detection unit. It is possible to reduce the transport resistance received by.

It is a figure which showed the structural example of the image forming apparatus of this embodiment. It is a figure which showed the structure around the cash register roll. It is a figure when the periphery of the register roll is viewed from the direction of arrow III of FIG. It is a figure when the periphery of CIS is viewed from the direction of arrow IV of FIG. (A), (b), and (c) are diagrams showing the pressing operation of the paper P by the pressing sheet when the patch image is detected by CIS after the patch image is formed on the first surface of the paper. Is. It is a flowchart which showed the flow of the detection process when the image formation is performed only on the 1st surface of a paper. It is a flowchart which showed the flow of the detection process when double-sided printing of a paper is performed. (A) and (b) are diagrams showing the configuration of a pressing device as another configuration example of the pressing means.

Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing a configuration example of the image forming apparatus 1 of the present embodiment.
The image forming apparatus 1 shown in FIG. 1 includes an image forming unit 100 that forms a toner image on paper P (recording medium) by, for example, an electrophotographic method.
Further, the image forming apparatus 1 includes a paper transport path 17 as an example of a transport path for transporting the paper P, and a paper accommodating unit 18 for accommodating the paper P.
Further, the image forming apparatus 1 includes a detecting device 30 that detects the paper P conveyed along the paper conveying path 17. Further, the image forming apparatus 1 includes a register roll 20 as an example of a recording medium transporting means for transporting the paper P to the downstream side after aligning the tips of the paper P to be conveyed along the paper transport path 17.

The image forming unit 100 includes a plurality of image forming units 11 (11Y, 11M, 11C, 11K) of yellow (Y), magenta (M), cyan (C), and black (K).
In the present embodiment, the image forming unit 100 that forms an image by an electrophotographic method is illustrated, but the image forming unit 100 may be configured by, for example, an inkjet printer.

Each image forming unit 11 includes a photoconductor drum 111 and a charging device 112 for charging the photoconductor drum 111. Further, the image forming unit 11 includes an exposure device 113 that exposes the surface of the photoconductor drum 111 charged by the charging device 112 to form an electrostatic latent image.
Further, the image forming unit 11 includes a developing device 114 that develops an electrostatic latent image formed on the photoconductor drum 111 by the exposure device 113 and forms a toner image on the photoconductor drum 111. Further, the image forming unit 11 includes a cleaning device 116 for removing waste toner on the photoconductor drum 111.

Further, the image forming unit 100 includes an intermediate transfer belt 12 on which each color toner image formed by the photoconductor drum 111 is multiplex transferred. Further, the image forming unit 100 includes a primary transfer roll 115 that sequentially transfers (primary transfer) each color toner image formed by the photoconductor drum 111 to the intermediate transfer belt 12.
Further, the image forming unit 100 includes a secondary transfer roll 13 that collectively transfers (secondary transfer) the toner image formed by superimposing the toner image on the intermediate transfer belt 12 onto the paper P which is a recording medium. Further, the image forming unit 100 includes a fixing unit 14 for fixing the secondary transferred toner image on the paper P.
Further, the image forming apparatus 1 includes a control unit 16 that controls the entire image forming apparatus 1.

The paper transport path 17 is provided with a first paper transport path R1 through which the paper P transported from the paper accommodating portion 18 toward the secondary transfer roll 13 passes. Further, as the paper transport path 17, a second paper transport path R2 through which the paper P passes after passing through the secondary transfer roll 13 is provided.
Further, as the paper transport path 17, a third paper transport path R3 that reverses the paper P and transports the inverted paper P to the first paper transport path R1 on the upstream side of the secondary transfer roll 13 It is provided.

The image forming apparatus 1 executes a series of image forming processes under the operation control by the control unit 16. That is, the image data acquired from a PC (not shown), a scanner, or the like (not shown) is subjected to image processing by the image processing unit (not shown), and is sent to the exposure device 113 as image data of each color. Then, in each image forming unit 11, exposure is performed by the exposure device 113, and further development is performed by the developer 114 to form a toner image on the photoconductor drum 111.

Each color toner image formed on the photoconductor drum 111 of each image forming unit 11 is sequentially electrostatically transferred (primary transfer) on the intermediate transfer belt 12 by the primary transfer roll 115, and each color is sequentially transferred on the intermediate transfer belt 12. A superimposed toner image on which toner is superimposed is formed.
The superimposed toner image on the intermediate transfer belt 12 is conveyed to the secondary transfer region T in which the secondary transfer roll 13 is arranged as the intermediate transfer belt 12 moves. On the other hand, the paper P is fed from the paper accommodating unit 18 and conveyed to the secondary transfer region T in accordance with the transfer timing of the superimposed toner image.

Then, the superimposed toner image on the intermediate transfer belt 12 is collectively electrostatically transferred (secondary transfer) on the conveyed paper P by the transfer electric field formed by the secondary transfer roll 13 in the secondary transfer region T. ). The paper P on which the superimposed toner image is electrostatically transferred is conveyed to the fixing unit 14 and fixed on the paper P by the fixing unit 14.

The fixed paper P is conveyed to a paper loading unit provided in the discharge unit of the image forming apparatus 1.
When performing so-called double-sided printing in which an image is formed on the other side of the paper P having an image formed on one side, the paper P is inverted through the third paper transport path R3. Then, the paper P is conveyed to the secondary transfer roll 13 again to form an image.

FIG. 2 is a diagram showing a configuration around the cash register roll 20. More specifically, FIG. 2 shows a state when the configuration around the cash register roll 20 is viewed from above.
In the present embodiment, the detection device 30, the registration roll 20, and the secondary transfer roll 13 are arranged in order from the upstream side in the transport direction of the paper P (direction of arrow A in the drawing).

The detection device 30 includes a CIS (Contact Image Sensor) 31 as an example of a detection unit that detects a side side (side side along the transport direction of the paper P) of the paper P transported along the paper transport path 17. In addition to detecting the side edges of the paper P, the CIS 31 can also detect an image formed on the paper P.

Further, the CIS 31 is provided on one end side of the register roll 20 in the axial direction. The configuration of the detection device 30 will be described in detail later.
The register roll 20 is provided so as to be movable in a direction intersecting the transport direction of the paper P (see the arrow B1 direction and the arrow B2 direction in the drawing). Further, a moving mechanism 20a for moving the register roll 20 is provided. The moving mechanism 20a is composed of, for example, a rack (not shown) interlocked with the register roll 20 and a pinion gear (not shown) rotated by a motor.

FIG. 3 is a view when the periphery of the register roll 20 is viewed from the direction of arrow III in FIG. More specifically, FIG. 3 shows a state when the configuration around the cash register roll 20 is viewed from one end side (the side opposite to the side where the CIS 31 is provided) in the axial direction of the cash register roll 20. There is.
Further, FIG. 4 is a view when the periphery of the detection device 30 is viewed from the direction of arrow IV in FIG. More specifically, FIG. 4 shows a state when the configuration around the detection device 30 is viewed from the downstream side in the transport direction of the paper P with respect to the detection device 30.

As shown in FIG. 3, a guide member 21 for guiding the paper P to be transported is provided on the side of the paper transport path 17. The guide member 21 is provided with a downward guide member 21b as an example of the first guide member and an upward guide member 21a as an example of the second guide member. The image forming unit 100 is located above the upward guide member 21a.

The downward guide member 21b is provided below the paper transport path 17. The upward guide member 21a is provided above the paper transport path 17 and is provided so as to face the downward guide member 21b.
A hinge for moving the upward guide member 21a (in FIG. 3) is provided at the inner end of the upward guide member 21a in the drawing (the end of the upper guide member 21a on the inner side of the paper surface in the direction intersecting the transport direction of the paper P). (Not shown) is provided. In the present embodiment, as shown in FIG. 4, the upward guide member 21a moves in the clockwise direction in the figure (in the direction of arrow E in the figure) with the hinge 21c as the center.

Further, as shown in FIG. 3, a pressing device 23 as an example of the pressing means for pressing the paper P is attached to the upward guide member 21a.
The pressing device 23 is formed of, for example, a polyester sheet such as a Mylar sheet (Mylar is a registered trademark). Further, as shown in FIG. 4, the pressing device 23 is provided so as to face a part of the CIS 31.

Further, the pressing device 23 is provided so as to be movable in the downward direction (direction of arrow C in FIG. 4). Further, a moving mechanism 23a for moving the pressing device 23 is provided. The moving mechanism 23a is composed of, for example, a motor (not shown) and a swing mechanism (not shown) that is driven by the motor and partially swings.
Then, when the detection device 30 detects the patch image (described later) formed on the paper P, the pressing device 23 presses the paper P conveyed to the opposite portion of the CIS 31 against the downward guide member 21b. The operation of pressing the paper P by the pressing device 23 will be described in detail later.

As shown in FIG. 4, the detection device 30 includes a reflector 32 as an example of a reflecting unit that reflects light. Further, the detection device 30 includes a CIS board 33 as an example of a circuit board that processes information from the CIS 31.
The CIS substrate 33 is arranged below the CIS 31. Further, both the CIS 31 and the CIS substrate 33 are installed on one side of the paper transport path 17 (the side on which the downward guide member 21b is provided). Further, the detection device 30 is provided with an electric wire 34 that connects the CIS 31 and the CIS substrate 33.

The reflector 32 is provided with a reflecting surface 32a that reflects light. The reflective surface 32a is formed of a metal material such as silver. The reflective surface 32a has a higher light reflectance than the paper P.
Further, the reflector 32 is attached to the upward guide member 21a. In the present embodiment, by providing the reflector 32 above the paper transport path 17, it is possible to prevent the paper dust generated from the paper P transported through the paper transport path 17 from falling and adhering to the reflector 32. NS.
As a result, the reflection of light is blocked by the paper dust adhering to the reflector 32, and the amount of light reflected by the reflector 32 is suppressed from being reduced. Further, the reflector 32 is provided so as to face a part of the CIS 31.

As shown in FIG. 4, the CIS 31 is attached to the downward guide member 21b. Further, the CIS 31 is provided with a plurality of light emitting elements (not shown) arranged along a direction intersecting the transport direction of the paper P. Further, the CIS 31 is provided with a plurality of light receiving elements (not shown) arranged in a direction intersecting the transport direction of the paper P.
While the paper P is being conveyed, the light emitting element emits light upward. The light emitted from the light emitting element is reflected by the reflector 32 and the paper P conveyed to the opposite portion of the light emitting element. The light reflected by the paper P and the reflector 32 is received by the light receiving element.

The CIS substrate 33 acquires information related to the amount of light received by the light receiving element from the CIS 31. Here, in the present embodiment, more light reflected by the reflecting surface 32a of the reflector 32 is received by the light receiving element than light reflected by the paper P. As a result, the CIS substrate 33 detects the side side of the paper P based on the magnitude of the amount of light received by the light receiving element.

The control unit 16 acquires the position of the side side of the paper P from the CIS board 33. Further, the control unit 16 calculates the amount of deviation of the position of the side side of the paper P from the reference position.
After that, the control unit 16 moves the registration roll 20 in a direction intersecting the transport direction of the paper P with the registration roll 20 sandwiching the paper P based on the calculated deviation amount. As a result, the misalignment of the side side on the paper P is corrected. The paper P is conveyed to the secondary transfer region T in a state where the position (the position in the direction intersecting the conveying direction of the paper P) is adjusted (see FIG. 3).

Further, in the present embodiment, when double-sided printing of the paper P is performed, a patch image is formed together with the image when the image is formed on the first side of the paper P.
Then, when the image is formed on the second surface of the paper P, the patch image formed on the first surface is detected by the detection device 30, and based on the position of the detected patch image, the paper P is formed. The position is corrected.

When double-sided printing of the paper P is performed, the misalignment of the paper P in the direction orthogonal to the transport direction is first corrected by the register roll 20 before the image is formed on the first side of the paper P.
Here, if the amount of misalignment of the paper P is large, the paper P reaches the secondary transfer region T before the correction of the position is completed. Therefore, if the amount of misalignment of the paper P is large, the position There will be a situation where the deviation cannot be corrected. In this case, an image is formed on the first surface of the paper P at a position deviated from the original position.

In such a case, when the position of the paper P is corrected with reference to the side side of the paper P when the image is formed on the second surface of the paper P, the image formed on the first surface and the image formed on the second surface are formed. A misalignment will occur between the and.
Therefore, in the present embodiment, in the correction of the position of the paper P when the image is formed on the second surface, the position of the paper P is corrected based on the patch image formed when the image is formed on the first surface. As a result, it is possible to prevent the image formed on the first surface from being displaced from the image formed on the second surface.

Further, in the configuration of the present embodiment, it is easy to clean the reflector 32 and the guide member 21.
If dust adheres to the portion of the downward guide member 21b to which the CIS 31 is attached or the reflector 32, the detection accuracy of the side surface of the paper P (detection accuracy by the detection device 30) may decrease. In order to suppress this, in the present embodiment, the operator cleans the reflector 32 and the guide member 21 through the opening formed by moving the upward guide member 21a in the direction of arrow E in FIG. In other words, the area around the guide member 21 is maintained.

In the present embodiment, as described above, both the CIS 31 and the CIS substrate 33 are installed on the side where the downward guide member 21b is provided.
Therefore, the electric wire 34 is arranged further below the downward guide member 21b. As a result, the operator can move the upward guide member 21a and maintain the vicinity of the guide member 21 without being interfered by the electric wire 34.

Further, in the present embodiment, as shown in FIG. 3, the CIS 31 and the CIS substrate 33 are installed on the side opposite to the side on which the image forming unit 100 is provided with the paper transport path 17 interposed therebetween.
As a result, the degree of freedom in layout in the image forming apparatus 1 is increased as compared with the case where the CIS 31 and the CIS substrate 33 and the image forming unit 11 are both provided on one side of the paper transport path 17. That is, it is prevented that members such as the CIS 31, CIS substrate 33, and the image forming unit 100 are arranged on one side of the paper transport path 17 in a state of high arrangement density, and the arrangement layout in the image forming apparatus 1 is prevented. Increases the degree of freedom.

5 (a), (b), and (c) show the pressing operation of the paper P by the pressing device 23 when the patch image F1 formed on the first surface of the paper P is detected by the CIS 31. Is.
As shown in FIG. 5A, the pressing device 23 is located above the paper transport path 17 before the paper P transported through the paper transport path 17 reaches the CIS 31.

Then, when it is detected by the sensor (not shown) that the paper P has reached the CIS 31, the control unit 16 drives the moving mechanism 23a and pushes the pressing device 23 downward (not shown) via the swing mechanism (not shown). Move in the direction of arrow C in the figure (see FIG. 5 (b)).

As a result, the tip end portion of the paper P (the tip end portion on the downstream side in the transport direction) is pressed against the downward guide member 21b by the pressing device 23. In this state, the patch image F1 formed on the paper P is detected by the CIS 31.
While the pressing device 23 is pressing the paper P against the downward guide member 21b, the paper P is conveyed in the conveying direction (direction of arrow A in the drawing).

When the patch image F1 formed on the paper P is detected by the CIS 31, the control unit 16 drives the moving mechanism 23a and pushes the pressing device 23 upward (in the direction of arrow D in the figure) as shown in FIG. 5 (c). ).
As a result, the pressing of the paper P by the pressing device 23 is released.

As described above, in the present embodiment, when the patch image F1 formed on the paper P is detected, the paper P is pressed against the downward guide member 21b. As a result, the detection accuracy of the patch image F1 by the detection device 30 is improved.
In the present embodiment, in the image detection of the paper P, the focal length of the CIS 31 is set to the distance H (focal length H) from the CIS 31 (light emitting element) to the upper surface of the downward guide member 21b (see FIG. 5 (b)).

Here, if the paper P is not pressed against the downward guide member 21b, the paper P may be conveyed with the portion of the paper P facing the CIS 31 floating from the downward guide member 21b (). See FIG. 5 (c)). When the paper P is conveyed in a floating state, the distance between the CIS 31 and the paper P becomes longer than the focal length H of the CIS 31.
In this case, the detection accuracy of the image formed on the paper P may decrease.

On the other hand, in the case of the configuration in which the paper P is pressed against the downward guide member 21b when the image formed on the paper P is detected as in the present embodiment, the distance between the CIS 31 and the paper P is the focal length H. Become closer to. In this case, the detection accuracy of the image formed on the paper P is improved.

FIG. 6 is a flowchart showing the flow of the detection process when the image is formed only on the first surface of the paper P.
First, when the paper P transported through the paper transport path 17 reaches the CIS 31, the CIS 31 detects the side side of the paper P (step 601).

Subsequently, the control unit 16 calculates the amount of deviation of the position of the side side of the paper P from the reference position, and moves the cash register roll 20 in a direction intersecting the conveying direction of the paper P based on the calculated amount of deviation. Step 602). As a result, the paper P is conveyed to the secondary transfer region T with the misalignment of the side sides corrected.

FIG. 7 is a flowchart showing the flow of the detection process when double-sided printing of the paper P is performed.
When double-sided printing of paper P is performed, CIS31 first detects the side edge of paper P (paper P when forming an image on the first side) (step 701), and then controls. By moving the register roll 20 by the unit 16 (step 702), the misalignment of the side side of the paper P is corrected.
Then, the paper P is conveyed to the secondary transfer region T, and an image is formed on the first surface. At this time, the patch image F1 is formed on the first surface (step 703).

The paper P on which the image is formed on the first surface reaches CIS31 again after the front and back sides are reversed. When the paper P reaches the CIS 31, the control unit 16 moves the pressing device 23 downward to press the paper P against the downward guide member 21b (step 704).

When the paper P is pressed against the downward guide member 21b, the CIS 31 detects the patch image F1 formed on the paper P (step 705). When the patch image F1 is detected, the control unit 16 moves the pressing device 23 upward to release the pressing of the paper P (step 706).

Subsequently, the control unit 16 calculates the amount of deviation of the position of the patch image F1 from the reference position based on the detection result of the patch image F1, and based on the calculated amount of deviation, the direction intersecting the conveying direction of the paper P. The cash register roll 20 is moved to (step 707). As a result, the paper P is conveyed to the secondary transfer region T in a corrected position, and an image is formed on the second surface of the paper P.

In the present embodiment, as described above, when the image is formed on the first surface of the paper P, the paper P is not pressed against the downward guide member 21b. That is, when the paper P for which the image formation has not been performed is conveyed, the paper P is not pressed against the downward guide member 21b by the pressing device 23. As a result, the transport resistance of the paper P is reduced.

In the present embodiment, as shown in FIG. 5B, the paper P is continuously conveyed in the direction of arrow A in the drawing while the paper P is pressed against the downward guide member 21b by the pressing device 23. During this time, the paper P receives a transport resistance force from the downward guide member 21b.
On the other hand, in the present embodiment, when the image is formed on the first surface of the paper P, the patch image F1 is not detected and the paper P does not need to be pressed against the downward guide member 21b. Is not pressed against the paper P. In this case, the transport resistance of the paper P is reduced.

Further, in the present embodiment, when the pressing device 23 presses the paper P against the downward guide member 21b, when the patch image F1 formed on the paper P is detected, the pressing device 23 presses the paper P. The operation is canceled.
As a result, the paper P is smoothly conveyed as compared with the case where the pressing of the paper P is continued even after the patch image F1 is detected.

In the present embodiment, when the position of the paper P deviates from the reference position, the position deviation is corrected by moving the paper P using the register roll 20.
Here, instead of moving the paper P, the position of the image formed on the paper P may be adjusted. That is, the control unit 16 may change the formation position of the toner image on the photoconductor drum 111 based on the amount of misalignment of the paper P.

Further, in the above, the case where the patch image F1 is formed when the image on the first surface of the paper P is formed and the patch image F1 is detected when the image is formed on the second surface of the paper P has been described.
By the way, not limited to this processing, when forming an image on the second surface, the side side of the paper P may be detected instead of detecting the patch image F1 as in the case of forming the image on the first surface. Then, in this case, the registration roll 20 is moved based on the detection result of the side side to correct the misalignment of the paper P.
Further, in the present embodiment, the reflector 32 has a configuration in which the reflectance of light is higher than that of the paper P. As a result, the side side can be detected more accurately when the image is formed on the second surface.

As shown in FIG. 4, when the side side of the paper P is detected when the image is formed on the second surface, the image F2 is already formed on the first surface of the paper P facing the CIS 31.
Here, when the image F2 is formed on the paper P, a brightness difference (hereinafter, referred to as an image / paper brightness difference) occurs between the image F2 and the paper P, and the lightness difference causes the image F2 and the paper. The boundary L with P may be detected as the side side of the paper P.

On the other hand, in the present embodiment, the brightness of the reflector 32 is large, and the difference in brightness between the paper P and the reflector 32 is larger than the difference in brightness between the image / paper.
In this case, the CIS substrate 33 of the present embodiment detects the boundary having the larger brightness difference as the side edge of the paper P. That is, the CIS substrate 33 detects the side side of the paper P, which is the boundary between the reflector 32 and the paper P, as the side side. This prevents the boundary L between the image F2 and the paper P from being erroneously detected as the side side of the paper P.

8 (a) and 8 (b) are views showing the configuration of the pressing device 24 as another configuration example of the pressing means. In FIGS. 8A and 8B, the right side in the figure is the upstream side in the transport direction, and the left side in the figure is the downstream side.
As shown in FIG. 8A, the pressing device 24 is provided above the upward guide member 21a. Further, the pressing device 24 includes a pressing portion 24a formed by pairing two legs having a rod shape. The two legs of the pressing portion 24a are aligned in a direction intersecting the conveying direction of the paper P.

The pressing portion 24a is provided along the conveying direction of the paper P (direction of arrow A in the drawing). Further, one end of the pressing portion 24a (the end on the downstream side in the transport direction of the paper P) is provided with an elastic portion 24b made of an elastically deformable rubber material.
Further, in the upward guide member 21a, a notch 21c that follows the shape of the pressing portion 24a and the elastic portion 24b is formed at a portion facing the pressing portion 24a and the elastic portion 24b.

A rotating shaft 24c is attached to the other end of the pressing portion 24a (the end on the upstream side in the transport direction of the paper P). The rotating shaft 24c rotatably supports the pressing portion 24a.
Further, a solenoid 24d is attached to the pressing portion 24a. The solenoid 24d receives power from the outside and drives the pressing portion 24a.

As shown in FIG. 8B, when the sensor (not shown) detects that the paper P has been conveyed to CIS31, the solenoid 24d rotates in the counterclockwise direction in the drawing with respect to the pressing portion 24a. Give power. The pressing portion 24a to which the rotational force is applied rotates in the counterclockwise direction in the drawing with the rotation shaft 24c as the center of rotation.
As a result, the elastic portion 24b moves in the direction of arrow E in the figure. Further, the elastic portion 24b passes through the notch 21c formed in the upward guide member 21a and enters the paper transport path 17.

The elastic portion 24b that has entered the paper transport path 17 presses the paper P against the downward guide member 21b. Further, at this time, the portion of the elastic portion 24b that comes into contact with the paper P is deformed into a shape along the downward guide member 21b.
When the patch image F1 (not shown in FIG. 8B) formed on the paper P is detected by the CIS 31, the solenoid 24d applies a rotational force to the pressing portion 24a in the clockwise direction in the drawing. As a result, the elastic portion 24b moves further upward than the upward guide member 21a, and the pressing of the paper P is released.

1 ... Image forming apparatus, 11 ... Image forming unit, 12 ... Intermediate transfer belt, 13 ... Secondary transfer roll, 16 ... Control unit, 17 ... Paper transport path, 20 ... Registrar roll, 21a ... Upward guide member, 21b ... Downward guidance Member, 23 ... Pushing device, 24 ... Pushing device, 24a ... Pushing part, 24b ... Elastic part, 24c ... Rotating shaft, 24d ... Solenoid, 30 ... Detection device, 31 ... CIS, 32 ... Reflecting plate, 33 ... CIS substrate, 34 ... Electric wire, 100 ... Image forming part

Claims (2)

The transport path through which the recording medium is transported and
An image forming unit that forms an image on the recording medium,
A detection unit provided on one side of the transport path and detecting a side side of the recording medium transported along the transport path along the recording medium transport direction.
A circuit board provided on one side of the transport path and processing information from the detection unit, and a circuit board.
A pressing means for pressing the recording medium located at a position facing the detection unit against a guide member located on the side of the transport path, and
With
The pressing means is an image forming apparatus that does not press the recording medium on which the image forming unit has not formed an image onto the guide member. The transport path through which the recording medium is transported and
An image forming unit that forms an image on the recording medium,
A detection unit provided on one side of the transport path and detecting a side side of the recording medium transported along the transport path along the recording medium transport direction.
A circuit board provided on one side of the transport path and processing information from the detection unit, and a circuit board.
A pressing means for pressing the recording medium located at a position facing the detection unit against a guide member located on the side of the transport path, and
With
The detection unit is configured to be capable of detecting an image formed on the recording medium.
The pressing means is an image forming apparatus that releases the pressing of the recording medium against the guide member when the image formed on the recording medium is detected by the detection unit.

Images