JP2019165478A - Image reading device and image forming apparatus - Google Patents

Abstract

To provide an image reading device that can improve the accuracy in reading an image position performed by a reading unit to accurately adjust the printing position of an image, and an image forming apparatus including the image reading device.SOLUTION: An image reading device comprises: a reading unit 9 that reads a reference image formed on a sheet to be conveyed in order to adjust the printing position of an image; a downstream roller (first downstream roller 112) that is provided on the downstream side in a conveyance direction of a reading position of the reading unit 9, and pushes the sheet to be conveyed toward a reading surface of the reading unit 9; and a control unit 1 that causes an image forming unit 8 forming an image on a sheet to form the reference image. The distance from the leading end of the sheet to the reference image formed on the sheet is shorter than the distance from the reading position of the reading unit 9 to the first downstream roller 112.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image reading apparatus and an image forming apparatus including the image reading apparatus.

An electrophotographic image forming apparatus forms a reference image for measuring a printing position (image forming position) on a sheet, and changes image forming conditions according to a printing position obtained by reading the reference image by a reading unit. The image print position is adjusted.
In a conventional image forming apparatus, when a paper height fluctuation or speed fluctuation occurs during reading of a reference image by the reading unit, adverse effects such as pitch unevenness and magnification fluctuation occur in the read image.

  Therefore, in order to solve the above problems, a configuration is provided in which a guide roller that can move on a plane perpendicular to the width direction of the conveyed paper is provided between the paper introduction unit guide roller and the calibration unit guide roller. It is disclosed (for example, see Patent Document 1). According to the configuration described in Patent Document 1, it is possible to control the posture of the paper at the time of paper entry, so it is possible to suppress the impact at the time of paper entry, and to transmit the fluctuation of the paper height and vibration to the reading unit. Can be suppressed.

Japanese Patent Laid-Open No. 2006-1814

However, although the technique described in Patent Document 1 can suppress the impact at the time of entering the sheet, it suppresses the impact generated by the collision between the leading end of the sheet and the conveyance roller after the sheet passes through the reading unit. I can't. Further, although the technique described in Patent Document 1 can suppress a large impact that affects the reading unit by controlling the position of a newly provided guide roller, it suppresses the impact generated on the sheet itself. I can't.
As described above, when the impact after passing through the reading unit or the impact on the sheet itself cannot be suppressed, the sheet bends or slips at the transport roller unit. There is a problem that accuracy decreases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading apparatus capable of improving the reading accuracy of an image position by a reading unit and accurately adjusting an image printing position, and an image forming apparatus including the image reading apparatus. To do.

The invention described in claim 1
To achieve the above objectives,
In an image reading apparatus including a reading unit that reads a reference image formed on a conveyed sheet in order to adjust an image printing position,
A downstream pressing unit that is provided on the downstream side in the transport direction from the reading position of the reading unit and pushes the transported paper toward the reading surface of the reading unit;
A control unit that forms the reference image in an image forming unit that forms an image on the paper;
An image reading apparatus, wherein a distance from a leading end of the sheet to the reference image formed on the sheet is shorter than a distance from a reading position of the reading unit to the downstream pressing unit.

The invention described in claim 2
In an image reading apparatus including a reading unit that reads a reference image formed on a conveyed sheet in order to adjust an image printing position,
An upstream side pressing unit that is provided upstream of the reading position of the reading unit in the conveying direction and pushes the conveyed paper toward the reading surface of the reading unit;
A control unit that forms the reference image in an image forming unit that forms an image on the paper;
The distance from the rear end of the sheet to the reference image formed on the sheet is shorter than the distance from the reading position of the reading unit to the upstream pressing unit.

The invention according to claim 3
The image reading apparatus according to claim 1,
The downstream pressing portion is provided as a downstream roller.

The invention according to claim 4
The image reading apparatus according to claim 1 or 3,
The downstream side pressing portion is configured to be movable up and down.

The invention described in claim 5
The image reading apparatus according to claim 2,
The upstream pressing portion is provided as an upstream roller.

The invention described in claim 6
The image reading apparatus according to claim 2 or 5,
The upstream pressing portion is configured to be movable up and down.

The invention described in claim 7
In the image reading apparatus according to any one of claims 1 to 6,
The control unit sets a print position of the reference image based on image forming conditions.

The invention according to claim 8 provides:
The image reading apparatus according to claim 7.
The control unit sets a print position of the reference image based on a paper type of the paper.

The invention according to claim 9 is:
The image reading apparatus according to claim 8.
A first type of paper and a second type of paper having a larger basis weight than the first type of paper can be conveyed;
The printing position of the reference image on the second type of paper is set to be closer to the inside of the paper than the printing position of the reference image on the first type of paper.

The invention according to claim 10 is:
The image reading apparatus according to claim 8 or 9,
The control unit sets a print position of the reference image based on an image print area of the paper.

The invention according to claim 11
The image reading apparatus according to claim 7.
The control unit sets a print position of the reference image based on an image print area of the paper.

The invention according to claim 12
The image reading apparatus according to claim 11.
The control unit may set the print position of the reference image to the inside of the paper as the image print area is narrower.

The invention according to claim 13
The image reading apparatus according to claim 11 or 12,
The control unit calculates the image print area based on the size of the paper, the size of the image formed on the paper, the print magnification, and the print position, and prints the reference image based on the calculated image print area. The position is set.

The invention according to claim 14
In the image forming apparatus,
An image forming unit that forms an image based on the image data;
A reading unit that reads a reference image formed on a sheet by the image forming unit in order to adjust an image printing position;
A downstream pressing unit that is provided on the downstream side in the transport direction from the reading position of the reading unit and pushes the transported paper toward the reading surface of the reading unit;
A control unit that causes the image forming unit to form the reference image,
The distance from the leading edge of the sheet to the reference image formed on the sheet is shorter than the distance from the reading position of the reading unit to the downstream pressing unit.

The invention according to claim 15 is:
In the image forming apparatus,
An image forming unit that forms an image based on the image data;
A reading unit that reads a reference image formed on a sheet by the image forming unit in order to adjust an image printing position;
An upstream side pressing unit that is provided upstream of the reading position of the reading unit in the conveying direction and pushes the conveyed paper toward the reading surface of the reading unit;
A control unit that causes the image forming unit to form the reference image,
The distance from the rear end of the sheet to the reference image formed on the sheet is shorter than the distance from the reading position of the reading unit to the upstream pressing unit.

The invention described in claim 16
The image forming apparatus according to claim 14.
The downstream pressing portion is provided as a downstream roller.

The invention described in claim 17
The image forming apparatus according to claim 14 or 16,
The downstream side pressing portion is configured to be movable up and down.

The invention described in claim 18
The image forming apparatus according to claim 15.
The upstream pressing portion is provided as an upstream roller.

The invention according to claim 19 is
The image forming apparatus according to claim 15 or 18,
The upstream pressing portion is configured to be movable up and down.

The invention according to claim 20 provides
The image forming apparatus according to any one of claims 14 to 19,
The control unit sets a print position of the reference image based on image forming conditions.

The invention according to claim 21
The image forming apparatus according to claim 20, wherein
The control unit sets a print position of the reference image based on a paper type of the paper.

The invention described in claim 22
The image forming apparatus according to claim 21, wherein
A first type of paper and a second type of paper having a larger basis weight than the first type of paper can be conveyed;
The printing position of the reference image on the second type of paper is set to be closer to the inside of the paper than the printing position of the reference image on the first type of paper.

  According to the present invention, it is possible to improve the reading accuracy of the image position by the reading unit and accurately adjust the printing position of the image.

1 is a schematic configuration diagram of an image forming apparatus according to an exemplary embodiment. It is a functional block diagram of a main body unit. It is a side view which shows the structure of a reading part. FIG. 6 is a diagram illustrating an example of a reference image for measuring a printing position formed on a sheet. 5 is a flowchart showing an operation of the image forming apparatus according to the present embodiment. FIG. 5 is a diagram illustrating an example of a table indicating a relationship between a paper size, a size of an image formed on the paper, a printing magnification, and a margin.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. In the following description, the horizontal direction in FIG. 1 is the X direction, the vertical direction is the Z direction, and the direction orthogonal to the X direction and the Z direction, that is, the front-rear direction is the Y direction.

  As shown in FIG. 1, the image forming apparatus G includes a print controller g1, a paper feed unit g2, a main body unit g3, and a post-processing device g4.

The print controller g1 receives PDL (Page Description Language) data from a computer terminal on the network, and rasterizes the PDL data to generate bitmap format image data.
The print controller g1 generates image data for each color of C (cyan), M (magenta), Y (yellow), and K (black), and outputs the image data to the main unit g3.

The sheet feeding unit g2 includes a plurality of large capacity sheet feeding trays.
The paper feeding unit g2 conveys paper from the paper feeding tray designated by the main body unit g3 to the main body unit g3.

The main unit g3 includes an operation unit 3, a display unit 4, an automatic document conveyance unit 61, a scanner unit 6, an image forming unit 8, a paper feed tray g31, a reading unit 9, a correction unit 10, and the like.
The main body unit g3 forms an image on the sheet by the image forming unit 8 based on the image data obtained by reading the document sheet D by the scanner unit 6 or the image data generated by the print controller g1. The main unit g3 conveys the sheet on which the image has been formed to the post-processing device g4.

  The post-processing device g4 performs post-processing on the paper conveyed from the main body unit g3 and discharges it. Examples of post-processing include stapling, punching, folding, and bookbinding. Post-processing is not essential, and the post-processing device g4 executes only when instructed by the main unit g3. When there is no post-processing, the post-processing device g4 discharges the conveyed paper as it is.

  As shown in FIG. 2, the main unit g3 includes a control unit 1, a storage unit 2, an operation unit 3, a display unit 4, a communication unit 5, an automatic document conveyance unit 61, a scanner unit 6, an image processing device 7, and an image forming unit. 8, the reading part 9, the roller drive part 200, and the correction | amendment part 10 are comprised.

The control unit 1 includes a CPU, a RAM, and the like. The control unit 1 reads a program stored in the storage unit 2 and controls each unit of the image forming apparatus G according to the program.
For example, the control unit 1 feeds paper by the paper feed unit g2 or the paper feed tray g31 in accordance with job settings. In addition, the control unit 1 corrects and processes image data using the image processing device 7 and causes the image forming unit 8 to form an image. If the job setting includes post-processing settings, the control unit 1 instructs the post-processing device g4 to perform post-processing.

  The storage unit 2 stores programs, files, and the like that can be read by the control unit 1. As the storage unit 2, for example, a storage medium such as a hard disk or a ROM (Read Only Memory) can be used. Further, the storage unit 2 stores a reference image for printing position measurement.

The operation unit 3 includes an operation key, a touch panel configured integrally with the display unit 4, and the like, and outputs operation signals corresponding to these operations to the control unit 1. The user can input an instruction to set a job, change processing contents, or the like through the operation unit 3.
The display unit 4 can be an LCD (Liquid Crystal Display) or the like, and displays an operation screen or the like according to an instruction from the control unit 1.
The communication unit 5 communicates with a computer on the network, for example, a server or another image forming apparatus, according to an instruction from the control unit 1.

The automatic document transport unit 61 includes a placement tray for placing the document paper D, a mechanism for transporting the document paper D, a transport roller, and the like, and transports the document paper D to a predetermined transport path.
The scanner unit 6 includes an optical system such as a light source and a reflecting mirror. The scanner unit 6 reads an image of the original paper D conveyed on a predetermined conveyance path or the original paper D placed on the platen glass, and R (red) ), Image data for each color of G (green) and B (blue) is generated and output to the image processing apparatus 7.

The image processing device 7 corrects the image data input from the scanner unit 6 or the print controller g 1, performs image processing, and outputs the image data to the image forming unit 8.
As illustrated in FIG. 2, the image processing apparatus 7 includes a color conversion unit 71, a gradation correction unit 72, and a halftone processing unit 73.

The color conversion unit 71 performs color conversion processing on the R, G, and B color image data output from the scanner unit 6 and outputs C, M, Y, and K color image data.
The color conversion unit 71 performs color conversion processing on the C, M, Y, and K color image data output from the print controller g1 for color correction, and performs color correction on the C, M, Y, and K colors. Image data can also be output.
At the time of color conversion processing, the color conversion unit 71 uses an LUT in which gradation values of C, M, Y, and K colors after color conversion are determined for gradation values of R, G, and B colors. . At the time of color correction, the color conversion unit 71 uses an LUT in which C, M, Y, and K gradation values after color correction are determined for the gradation values of C, M, Y, and K colors.

The gradation correction unit 72 corrects the gradation of the image data output from the color conversion unit 71 or the print controller g1.
The gradation correction unit 72 uses an LUT in which correction values corresponding to the respective gradation values are determined so that the gradation characteristics of the image coincide with the target gradation characteristics at the time of gradation correction. The gradation correction unit 72 obtains a correction value corresponding to the gradation value of each pixel of the image data from the gradation correction LUT, and outputs image data including the correction value.

The halftone processing unit 73 performs halftone processing on the image data output from the gradation correction unit 72. The halftone processing is, for example, screen processing using a dither matrix, error diffusion processing, or the like.
The halftone processing unit 73 outputs the image data after the halftone processing to the image forming unit 8.

The image forming unit 8 forms an image on a sheet based on the image data output from the image processing device 7.
As shown in FIG. 1, the image forming unit 8 includes four sets of an exposure unit 81, a photosensitive member 82, and a developing unit 83 for each of C, M, Y, and K colors. The image forming unit 8 includes an intermediate transfer belt 84, a secondary transfer roller 85, a fixing device 86, and a reversing mechanism 87.

The exposure unit 81 includes an LD (Laser Diode) as a light emitting element. The exposure unit 81 drives the LD based on the image data, and exposes the photosensitive member 82 to be charged by irradiating it with laser light. The developing unit 83 supplies toner onto the photoconductor 82 by a developing roller that is charged, and develops the electrostatic latent image formed on the photoconductor 82 by exposure.
The images formed with the toners of the respective colors on the four photoconductors 82 in this way are sequentially transferred from the photoconductors 82 onto the intermediate transfer belt 84 in an overlapping manner. As a result, a color image is formed on the intermediate transfer belt 84. The intermediate transfer belt 84 is an endless belt wound around a plurality of rollers, and rotates according to the rotation of each roller.

  The secondary transfer roller 85 transfers the color image on the intermediate transfer belt 84 onto the paper fed from the paper feed unit g2 or the paper feed tray g31. The fixing device 86 heats and pressurizes the transferred paper and performs a fixing process.

  When forming images on both sides of the paper, the image forming unit 8 reverses the front and back of the paper with the reversing mechanism 87 and forms an image on the other side. The reversing mechanism 87 has a transport path for reversing the front and back of the passing paper and transporting the paper again to the transfer position by the secondary transfer roller 85.

As shown in FIGS. 1 and 3, the reading unit 9 is provided on the lower side of the conveyance path, and is formed on the paper P conveyed from the upstream conveyance path R <b> 1 provided on the upstream side of the reading unit 9 in the conveyance direction. The read image is read. The paper P on which an image has been read by the reading unit 9 is conveyed from the downstream conveyance path R2 provided on the downstream side in the conveyance direction to the post-processing device g4. When the reading unit 9 reads an image, the paper P is moved at a predetermined speed by a plurality of transport rollers (upstream transport roller 88a, downstream transport roller 88b, etc.) provided on the transport path. The paper is conveyed so as to pass.
The reading unit 9 includes a CCD (Charge Coupled Device) 91 as an optical sensor that reads an image formed on the paper P at a predetermined reading position L, and an optical system for guiding the image at the reading position L to the CCD 91. 92, an LED (Light Emitting Diode) light source 93 that illuminates the reading position L, and the like.

The CCD 91 is a color line sensor capable of reading the entire width range in the width direction (Y direction) of the paper P. The CCD 91 is supported at a predetermined position by a CCD mounting frame 911 via a support member 912.
The optical system 92 includes a plurality of mirrors and a plurality of lenses.
Since the reading unit 9 has the above-described configuration, the image formed on the paper P can be sequentially read over the entire width of the paper P passing through the reading position L.

  In this embodiment, the reference image K1 for measuring the printing position is a cross-shaped mark as shown in FIG. The control unit 1 measures the distances A1 and B1 (see FIG. 4) from the edge of the paper P to the adjacent reference image K1 based on the reference image K1 read by the reading unit 9, and actually measures the reference image K1. Calculate the print position. Then, the control unit 1 adjusts the printing position so that an image is formed at the original printing position after the next time.

Further, a calibration unit 94 is provided above the reading unit 9 so as to sandwich the conveyance path.
The calibration unit 94 includes a white reference plate for determining a correction value for shading correction performed when reading an image. The white reference plate is provided at the reading position L, and is read by the CCD 91 with a gap when the paper P is not passing (for example, between the paper P and the paper P).

As shown in FIG. 3, an upstream guide member 101 and a downstream guide member 102 are provided on the lower surface of the calibration unit 94 on the upstream side in the transport direction and the downstream guide member 102 on the downstream side in the transport direction, respectively.
By the upstream guide member 101 and the downstream guide member 102, the upward movement of the paper P is restricted and the reading position L can be passed.

As shown in FIG. 3, the upper surface of the reading unit 9, that is, the surface on the paper conveyance path side, is located upstream of the reading position L of the reading unit 9 in the conveyance direction and opposed to the upstream guide member 101. A first upstream roller (upstream roller) 111 is provided, and a first downstream roller (downstream roller) 112 is provided at a position downstream of the reading position L in the transport direction and facing the downstream guide member 102. The first upstream roller 111 and the first downstream roller 112 are each inserted through a rotation axis that is orthogonal to the transport direction, and can rotate about the rotation axis.
Further, the first upstream roller 111 and the first downstream roller 112 are configured to be movable up and down by the roller driving unit 200, respectively. The first upstream roller 111 and the first downstream roller 112 move upward when the paper P is conveyed, so that the paper P can be pushed upward and pressed against the reading surface of the calibration unit 94.

  The roller driving unit 200 controls the control unit 11 to move the first upstream roller 111 and the first downstream roller 112 upward during the conveyance of the paper P, thereby pushing the paper P upward to be on the reading surface of the calibration unit 94. Perform the pressing operation. At this time, the controller 11 controls the roller driving unit 200 so that the heights of the first upstream roller 111 and the first downstream roller 112 become a predetermined height based on the paper type (basis weight) of the conveyed paper. To control. Specifically, when the basis weight of the paper is large, the control unit 11 controls the roller driving unit 200 so that the heights of the first upstream roller 111 and the first downstream roller 112 are relatively low. Control. On the other hand, when the basis weight of the sheet is small, the control unit 11 controls the roller driving unit 200 so that the heights of the first upstream roller 111 and the first downstream roller 112 are relatively high.

On the upper surface side of the calibration unit 94, the second upstream roller 121 is located on the upstream side in the conveying direction with respect to the reading position L and downstream of the first upstream roller 111, and the first downstream roller 112 on the downstream side in the conveying direction. The second downstream rollers 122 are provided on the upstream side. Each of the second upstream roller 121 and the second downstream roller 122 is inserted through a rotation shaft that is orthogonal to the transport direction, and is rotatable about the rotation shaft.
A reading surface for reading an image formed on the paper P is formed by the second upstream roller 121 and the second downstream roller 122. That is, the second upstream roller 121 and the second downstream roller 122 serve as a reference for the paper height when the reading unit 9 reads an image. Further, as described above, when the paper P is transported, the first upstream roller 111 and the first downstream roller 112 are moved upward, and the paper P is moved to the reading surface of the calibration unit 94 (the second upstream roller 121 and the second downstream roller 122). ), The sheet height when reading the image can be kept constant.

  The upstream transport path R1 is provided so as to be inclined upward with respect to the transport direction so that an upward pressing force can be applied to the paper transported to the reading unit 9. The downstream transport path R2 is provided so as to be inclined downward with respect to the transport direction so that a downward pressing force can be applied to the paper transported from the reading unit 9.

  The correction unit 10 corrects the deformation of the fixed paper and planarizes the paper surface. Here, the sheet is easily deformed by the fixing process, and the sheet needs to be flattened when the reference image is read. Therefore, as shown in FIG. 1, the correction unit 10 is disposed between the fixing device 86 and the reading unit 9 in the sheet conveyance direction.

  The image reading apparatus of the present invention includes at least a reading unit 9, a first upstream roller 111, a first downstream roller 112, and a control unit 1 as a print position setting unit.

  Next, the operation of the image forming apparatus G according to the present embodiment will be described with reference to the flowchart of FIG. This operation is started when the control unit 11 receives a print position adjustment mode selection operation by the user.

First, the control unit 1 reads the paper type setting of a paper preset by the user, and determines whether or not the paper to be transported is a thick paper (step S101). Here, the paper types preset by the user are “thick paper”, “regular paper (medium amount)”, and “thin paper”. In this embodiment, a sheet having a basis weight of 40 to 64 g / m 2 is defined as “thin paper”, a sheet having 65 to 199 g / m 2 is defined as “regular paper”, and a sheet having 200 to 350 g / m 2 is defined as “thick paper”.
When the control unit 1 determines that the paper to be conveyed is thick paper (step S101: YES), the control unit 1 sets the printing position of the reference image for printing position measurement to the thick paper position (thick paper position) (step S102). ).
On the other hand, when the control unit 1 determines that the sheet to be transported is not a thick sheet (step S101: NO), the printing position of the reference image for printing position measurement is set to a position for other sheets (position for other sheets). (Step S103).

  In the present embodiment, the reference image printing position is set to a position where the timing at which the impact occurs at the leading and trailing edges of the paper and the timing at which the reading unit 9 reads the reference image do not overlap. That is, the control unit 1 functions as a print position setting unit of the present invention. More specifically, the printing position of the reference image has a distance A1 (see FIG. 4) from the leading edge of the sheet to the reference image, and a distance a1 from the reading position of the reading unit 9 to the first downstream roller 112 (see FIG. 3). ) And the distance A2 (see FIG. 4) from the rear end of the sheet to the reference image is larger than the distance a2 (see FIG. 3) from the reading position of the reading unit 9 to the first upstream roller 111. Is set to be shorter.

  Here, the thick paper position is set so that the reference image print position is closer to the inside of the paper than the other paper position. In the case of thick paper, when the belt is transferred, when the fixing roller enters after transfer, or when the nip of the rear edge of the paper is removed, the edge of the paper is likely to be impacted, resulting in transfer misalignment. This is because the image position may not be read correctly.

For example, when the first downstream roller 112 is arranged at a position 15 mm from the reading position L of the reading unit 9, if the basis weight of the paper is 200 g / m 2 or more, the printing position is 10 mm from the edge of the paper (the position for thick paper) ) (See step S102), and if it is less than 200 g / m ² , the print position is set to a position 5 mm from the edge of the paper (position for other paper) (see step S103).

Next, the control unit 1 determines whether or not the print position of the reference image at the time of transporting thick paper is manually set by the user (step S104).
When the control unit 1 determines that the reference image print position at the time of transporting thick paper is manually set by the user (step S104: YES), the control unit 1 reflects the manual setting on the reference image print position set in step S102 ( Step S105). For example, if the print position of the reference image is manually set to 8 mm by the user when transporting thick paper, the print position setting is changed from a position of 10 mm from the edge of the paper (position for thick paper) to a position of 8 mm.
On the other hand, when the control unit 1 determines that the printing position of the reference image at the time of transporting thick paper is not manually set by the user (step S104: NO), the control unit 1 proceeds to step S106.

Next, the control unit 1 starts conveying the paper, and causes the image forming unit 8 to form a reference image at the print position set above (step S106).
Next, the control unit 1 acquires a print position obtained by reading the reference image formed on the sheet in step S106 by the reading unit 9 (step S107).
Next, the control unit 1 changes the image forming conditions according to the print position acquired in step S107, and adjusts the print position of the image (step S108).

As described above, the image forming apparatus G according to the present embodiment is provided on the sheet conveyance path side surface of the reading unit 9 and on the upstream side of the reading position of the reading unit 9 in the conveyance direction, and can move up and down. The upstream roller (first upstream roller 111) configured in the above and the surface of the reading unit 9 on the sheet conveyance path side, which is provided on the downstream side in the conveyance direction from the reading position of the reading unit 9, and can move up and down. The configured downstream roller (first downstream roller 112) does not overlap with the timing at which an impact is generated at the leading and trailing edges of the sheet and the timing at which the reference image for measuring the print position formed on the sheet by the reading unit 9 is read. And a printing position setting unit (control unit 1) for setting a printing position of the reference image at the position.
Therefore, according to the image forming apparatus G according to the present embodiment, it is possible to suppress the occurrence of an impact at the time of image reading by the reading unit 9 and to suppress the speed fluctuation of the paper. The accuracy can be improved, and the printing position of the image can be adjusted accurately.

Further, according to the image forming apparatus G according to the present embodiment, the print position setting unit is configured such that the distance from the leading edge of the sheet to the reference image is shorter than the distance from the reading position of the reading unit 9 to the downstream roller. In addition, the reference image printing position is set so that the distance from the rear end of the sheet to the reference image is shorter than the distance from the reading position of the reading unit 9 to the upstream roller.
Therefore, according to the image forming apparatus G according to the present embodiment, it is possible to suppress the occurrence of an impact caused by a collision between the leading edge of the sheet and the downstream roller or a nip missing at the trailing edge of the sheet when the reading unit 9 reads an image. Since fluctuations in the speed of the paper can be suppressed, the reading accuracy of the image position by the reading unit 9 can be improved, and the print position of the image can be adjusted accurately.

Further, according to the image forming apparatus G according to the present embodiment, the print position setting unit sets the print position of the reference image based on the image forming conditions. Here, the image forming conditions are, for example, the paper type of the paper, the image printing area of the paper, and the like.
For example, according to the image forming apparatus G according to the present embodiment, the print position setting unit sets the print position of the reference image based on the paper type. Specifically, the printing position setting unit sets the printing position of the reference image closer to the inner side of the paper than the other paper when the conveyed paper is thick paper.
Therefore, according to the image forming apparatus G according to the present embodiment, since the image can be transferred and fixed while avoiding the influence of the impact on the edge of the paper, it is possible to suppress the bleeding of the reference image. The reading accuracy of the image position by the reading unit 9 can be improved.

  As mentioned above, although concretely demonstrated based on embodiment which concerns on this invention, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.

  For example, in the above embodiment, when the transported paper is thick paper, the print position of the reference image is set to be closer to the inside of the paper than other papers, but the present invention is not limited to this. It is not a thing. That is, any type of paper can be used as long as the image tends to bleed in the vicinity of the edge of the paper. For example, when the transported paper is recycled paper, embossed paper, wind paper, etc., the reference image is printed. The position may be set so as to be closer to the inner side of the sheet than other sheets.

  In the above-described embodiment, when the print position of the reference image at the time of transporting thick paper is manually set by the user, the manual setting is reflected. However, the present invention is not limited to this. For example, even if the printing position of the reference image when the thick paper is conveyed manually by the user, the printing position of the standard image is automatically set to the thick paper position (see step S102 in FIG. 5). May be.

  As described above, when the paper type is a predetermined paper type (for example, thick paper), the print position setting unit sets the print position of the reference image automatically or based on a manual setting by a user operation. Since the print position can be set according to the situation, the print position suitable for the purpose can be adjusted.

  The print position of the reference image may be set based on the image print area of the conveyed paper. More specifically, the printing position of the reference image may be set to the inner side of the sheet as the image printing area of the conveyed sheet is narrower. The image print area is calculated based on, for example, the size of the paper, the size of the image formed on the paper, the print magnification, and the print position.

FIG. 6 shows an example of a table T1 showing the relationship between the paper size, the size of the image formed on the paper, the print magnification, and the margin. The table T1 has fields of a paper size T11, an image size T12, a printing magnification T13, a total margin T14 in the transport direction, and a one-side margin T15 in the transport direction. FIG. 6 shows an example in which the image is formed at the center position of the paper.
From the first record of the table T1, the sheet size T11 is “A3 (420 mm length)”, the image size T12 is “A4 (297 mm length)”, and the printing magnification T13 is “1.0” times. It can be read that the total margin T14 in the direction is “123 mm” and the one-side margin T15 in the transport direction is “61.5 mm”. Also, from the second record, when the paper size T11 is “SRA3 (450 mm length)”, the image size T12 is “A3 (420 mm length)”, and the printing magnification T13 is “1.0” times, the transport direction It can be read that the total margin T14 is “30 mm” and the one-side margin T15 in the transport direction is “15 mm”. Also, from the third record, when the paper size T11 is “A3 (420 mm length)”, the image size T12 is “A3 (420 mm length)”, and the print magnification T13 is “0.5” times, the transport direction It can be read that the total margin T14 is “210 mm” and the one-side margin T15 in the transport direction is “105 mm”.

  As described above, the print position setting unit can set the print position according to the image to be formed by setting the print position of the reference image based on the image print area of the paper. The print position can be adjusted with high accuracy.

  In particular, the print position setting unit can set the print position suitable for the image to be formed by setting the print position of the reference image inside the paper as the image print area is narrower. The print position can be adjusted well.

  The print position setting unit calculates an image print area based on the size of the paper, the size of the image formed on the paper, the print magnification, and the print position, and prints the reference image based on the calculated image print area. Since the image print area can be accurately extracted and the print position can be set, the print position can be adjusted with higher accuracy.

  In the above embodiment, a configuration is adopted in which the calibration unit 94 is disposed above and the reading unit 9 is disposed below the conveyance path. However, the present invention is not limited to this. For example, a configuration in which the reading unit 9 is disposed above and the calibration unit 94 is disposed below the conveyance path may be employed.

  Moreover, in the said embodiment, although the structure which arrange | positions the reading part 9 and the calibration part 94 1 each is employ | adopted, it is not limited to this. For example, a configuration in which two reading units 9 and two calibration units 94 are arranged may be employed. In this case, one employs a configuration in which the calibration unit 94 is disposed below and the reading unit 9 is disposed below the conveyance path, and the other is configured such that the reading unit 9 is disposed downward and the calibration unit 94 across the conveyance path. By adopting the configuration in which each is arranged, it is possible to read the image on each side, so that the images on both sides of the paper can be read with one paper conveyance.

  In addition, the detailed configuration of each apparatus constituting the image forming apparatus and the detailed operation of each apparatus can be changed as appropriate without departing from the spirit of the present invention.

G Image forming apparatus 1 Control unit (print position setting unit)
2 storage unit 3 operation unit 4 display unit 8 image forming unit 88a upstream conveyance roller 88b downstream conveyance roller 9 reading unit 94 calibration unit 101 upstream guide member 102 downstream guide member 111 first upstream roller (upstream roller)
112 First downstream roller (downstream roller)
121 Second upstream roller 122 Second downstream roller R1 Upstream conveyance path R2 Downstream conveyance path

Claims (22)

In an image reading apparatus including a reading unit that reads a reference image formed on a conveyed sheet in order to adjust an image printing position,
A downstream pressing unit that is provided on the downstream side in the transport direction from the reading position of the reading unit and pushes the transported paper toward the reading surface of the reading unit;
A control unit that forms the reference image in an image forming unit that forms an image on the paper;
An image reading apparatus, wherein a distance from a leading end of the sheet to the reference image formed on the sheet is shorter than a distance from a reading position of the reading unit to the downstream pressing unit. In an image reading apparatus including a reading unit that reads a reference image formed on a conveyed sheet in order to adjust an image printing position,
An upstream side pressing unit that is provided upstream of the reading position of the reading unit in the conveying direction and pushes the conveyed paper toward the reading surface of the reading unit;
A control unit that forms the reference image in an image forming unit that forms an image on the paper;
An image reading apparatus, wherein a distance from a rear end of the sheet to the reference image formed on the sheet is shorter than a distance from a reading position of the reading unit to the upstream pressing unit.   The image reading apparatus according to claim 1, wherein the downstream side pressing portion is provided as a downstream roller.   The image reading apparatus according to claim 1, wherein the downstream pressing portion is configured to be movable up and down.   The image reading apparatus according to claim 2, wherein the upstream pressing portion is provided as an upstream roller.   The image reading apparatus according to claim 2, wherein the upstream pressing portion is configured to be movable up and down.   The image reading apparatus according to claim 1, wherein the control unit sets a print position of the reference image based on an image forming condition.   The image reading apparatus according to claim 7, wherein the control unit sets a print position of the reference image based on a paper type of the paper. A first type of paper and a second type of paper having a larger basis weight than the first type of paper can be conveyed;
The printing position of the reference image on the second type of paper is set to be closer to the inside of the paper than the printing position of the reference image on the first type of paper. Item 9. The image reading apparatus according to Item 8.   9. The control unit according to claim 8, wherein when the paper type is a predetermined paper type, the control unit sets a print position of the reference image automatically or based on a manual setting by a user operation. The image reading apparatus according to 9.   The image reading apparatus according to claim 7, wherein the control unit sets a print position of the reference image based on an image print area of the paper.   The image reading apparatus according to claim 11, wherein the control unit sets the printing position of the reference image inside the sheet as the image printing area is narrower.   The control unit calculates the image print area based on the size of the paper, the size of the image formed on the paper, the print magnification, and the print position, and prints the reference image based on the calculated image print area. The image reading apparatus according to claim 11, wherein the position is set. An image forming unit that forms an image based on the image data;
A reading unit that reads a reference image formed on a sheet by the image forming unit in order to adjust an image printing position;
A downstream pressing unit that is provided on the downstream side in the transport direction from the reading position of the reading unit and pushes the transported paper toward the reading surface of the reading unit;
A control unit that causes the image forming unit to form the reference image,
An image forming apparatus, wherein a distance from a leading end of the sheet to the reference image formed on the sheet is shorter than a distance from a reading position of the reading unit to the downstream pressing unit. An image forming unit that forms an image based on the image data;
A reading unit that reads a reference image formed on a sheet by the image forming unit in order to adjust an image printing position;
An upstream side pressing unit that is provided upstream of the reading position of the reading unit in the conveying direction and pushes the conveyed paper toward the reading surface of the reading unit;
A control unit that causes the image forming unit to form the reference image,
An image forming apparatus, wherein a distance from a rear end of the sheet to the reference image formed on the sheet is shorter than a distance from a reading position of the reading unit to the upstream pressing unit.   The image forming apparatus according to claim 14, wherein the downstream side pressing portion is provided as a downstream roller.   The image forming apparatus according to claim 14, wherein the downstream pressing portion is configured to be movable up and down.   The image forming apparatus according to claim 15, wherein the upstream pressing portion is provided as an upstream roller.   The image forming apparatus according to claim 15, wherein the upstream pressing portion is configured to be movable up and down.   The image forming apparatus according to claim 14, wherein the control unit sets a print position of the reference image based on an image forming condition.   The image forming apparatus according to claim 20, wherein the control unit sets a print position of the reference image based on a paper type of the paper. A first type of paper and a second type of paper having a larger basis weight than the first type of paper can be conveyed;
The printing position of the reference image on the second type of paper is set to be closer to the inside of the paper than the printing position of the reference image on the first type of paper. Item 22. The image forming apparatus according to Item 21.

Images