JP2021097291A - Image forming apparatus and image position adjustment method - Google Patents

Abstract

To provide an image forming apparatus and an image position adjustment method that, even when the accuracy of cutting a paper bundle used for printing is not sufficient, can obtain a good printing result in which positional deviation of images between sheets is small after cutting in a post process.SOLUTION: According to an image forming apparatus, a control unit has, as an operation mode of image position adjustment, a first adjustment mode for adjusting the position of an image printed on a sheet by an image forming unit before printing and a second adjustment mode for adjusting the position of the image printed on the sheet by the image forming unit during the printing. During the operation in the second adjustment mode, the control unit restricts execution of at least magnification adjustment, of adjustment items executed in the first adjustment mode.SELECTED DRAWING: Figure 12

Description

The present invention relates to an image forming apparatus and an image position adjusting method.

In the printing industry, an image is printed together with a cutting register on a paper having a size larger than the final product, and post-processing including cutting is performed after printing. However, since the printing paper is not necessarily a rectangle having an accurate size, a lot of labor has been devoted to the process of accurately cutting at the cutting register position during the cutting work.

Therefore, for example, in Patent Document 1, the first paper cutting position is shown on the cut paper bundle, and the image position is controlled to be aligned with the side opposite to the first paper cutting position, so that the cutting work can be easily performed. The technology is disclosed. Patent Document 1 proposes a means for measuring image distortion based on a distance between a paper outer shape and a measurement pattern (dragonfly) for measuring an image position, and adjusting the image position by image deformation. There is.

In addition, in order to sequentially measure and correct the positional deviation of the image over time during printing, dragonflies are printed at the four corners of the image to be printed, and the distance between this and the paper edge (paper edge) is measured and the paper is printed. A method (called real-time adjustment) of adjusting the image misalignment during printing by adjusting the distance between the edge and the dragonfly at the four corners to be constant is generally used. By real-time adjustment, it is possible to appropriately respond to changes over time in the image forming apparatus during continuous printing and realize good image alignment.

Japanese Unexamined Patent Publication No. 2017-76845

As described above, when the image position adjustment is performed based on the positional relationship between the paper edge and the register marks at the four corners, no particular problem occurs if the cutting accuracy of the paper bundle used for printing is sufficient, but the paper cutting accuracy is poor. In this case, the positional relationship between the paper edge and the dragonfly at the four corners changes "due to the paper" as the printing progresses, and if adjusted to stabilize this, the image magnification changes and the image position shifts in the post-processing cutting process. There was a case.

FIG. 13A shows an image of an accurately cut paper bundle. As shown in FIG. 13A, the paper bundle cut into a rectangular shape is always stable as shown in FIG. 13B by adjusting the distance between the paper edge and the register marks at the four corners as needed. The image can be printed at the image position. In FIG. 13B, the inside of the registration marks at the four corners is the image position. (The same applies to FIG. 14B).

FIG. 14A shows an image of a bundle of paper in which the paper size increases toward the bottom as an example of a bundle of paper in which cutting is inaccurate. As shown in FIG. 14A, when the cutting state of the paper bundle used for printing is distorted, the paper size changes as the printing progresses. In this case, if the image positions are adjusted so that the distances between the paper edges and the registration marks at the four corners are constant, the image positions with respect to each paper edge are stable as shown in FIG. 14B, but the image changes as the paper size changes. If the paper bundle after printing is cut based on the position at the start of printing, the image position after cutting will be the time when printing starts (using the paper above the paper bundle) and the time when printing ends (using the paper above the bundle). The situation changes depending on the paper bundle below the paper bundle). Further, when cutting, the paper printed at the end of printing is cut at the position of the dotted line in FIG. 14B, so that the image may protrude from the paper.

INDUSTRIAL APPLICABILITY The present invention provides an image forming apparatus and an image position adjustment that can obtain good printing results with little image misalignment between papers after cutting in a subsequent step even when the cutting accuracy of a bundle of papers used for printing is not sufficient. The purpose is to provide a method.

In order to solve the above problems, the image forming apparatus of the invention according to claim 1 is used.
An image forming means for forming an image on paper,
An image position adjusting means for adjusting the position of an image printed on the paper by the image forming means based on the positional relationship between the edge of the paper and the measurement pattern printed on the paper by the image forming means.
An image forming apparatus equipped with
The image position adjusting means is printed on the paper by the image forming means during the main printing and a first adjustment mode for adjusting the position of the image printed on the paper by the image forming means before the main printing. It has a second adjustment mode for adjusting the position of the image, and limits the execution of at least the magnification adjustment among the adjustment items performed in the first adjustment mode when operating in the second adjustment mode. ..

The invention according to claim 2 is the invention according to claim 1.
The second adjustment mode has a first mode that does not limit the execution of the magnification adjustment and a second mode that limits the execution of the magnification adjustment.
A selection means for selecting the first mode or the second mode is provided.

The invention according to claim 3 is the invention according to claim 1 or 2.
The second adjustment mode has a third mode that limits the implementation of the magnification adjustment and further adjusts the front-back difference of the image printed on the front and back of the paper.

The invention according to claim 4 is the invention according to claim 3.
In the third mode, the front and back of the image printed on the front and back of the paper are adjusted by adjusting the magnification of the image of the surface to be printed later with reference to the image of the surface to be printed first in the image forming means. Adjust the difference.

The invention according to claim 5 is the invention according to claim 3.
In the third mode, the position of the surface to be printed later is minimized on average at the four corners with respect to the image of the surface to be printed first in the image forming means. Adjust the position of the image.

The invention according to claim 6 is the invention according to any one of claims 1 to 5.
Of the plurality of adjustment modes included in the second adjustment mode, each of the adjustment modes for limiting the execution of the magnification adjustment includes an image printed on at least one side of the paper by the image forming means and the paper. An adjustment mode that adjusts the position of the image so that the distance to a specific edge is a predetermined distance, and the position of the image so that the position of the image printed on the paper by the image forming means is located at the center of the paper. Any of the adjustment modes to adjust is configured to be selectable.

The invention according to claim 7 is the invention according to any one of claims 2 to 6.
When the adjustment is performed in the second adjustment mode, the image position adjusting means calculates the adjustment values of at least two adjustment modes included in the second adjustment mode and stores them in the storage means.

The invention according to claim 8 is the invention according to any one of claims 1 to 7.
When limiting the execution of the magnification adjustment in the second adjustment mode, as compared with the case where the distance between the measurement pattern printed on the paper by the image forming means and the edge of the paper does not limit the execution of the magnification adjustment. A measurement pattern adjusting means for adjusting the position of the measurement pattern so as to increase the size is provided.

The invention according to claim 9 is
An image position adjustment method for adjusting the position of an image printed on paper by the image forming means based on the positional relationship between the edge of the paper and the measurement pattern printed on the paper by the image forming means.
The first adjustment mode for adjusting the position of the image printed on the paper by the image forming means before the main printing, and the first adjustment mode for adjusting the position of the image printed on the paper by the image forming means during the main printing. It has two adjustment modes, and limits the execution of at least the magnification adjustment among the adjustment items performed in the first adjustment mode when operating in the second adjustment mode.

According to the present invention, even when the cutting accuracy of a bundle of paper used for printing is not sufficient, an image forming apparatus and an image that can obtain good printing results with little misalignment of images between papers after cutting in a subsequent step. It becomes possible to provide a position adjustment method.

It is a block diagram which shows the functional structure of an image forming apparatus. It is a figure which shows the mechanical component of each part of an image forming apparatus. It is a figure for demonstrating the background member. It is a figure which shows an example of the registration mark printed in the 1st adjustment mode. It is a figure which shows the range of the adjustment value and the adjustment image in each adjustment item of the vertical magnification, the horizontal magnification, the vertical image shift, and the left-right image shift. It is a figure which shows the range of the adjustment value and the adjustment image in each adjustment item of rotation, skew, vertical trapezium, horizontal trapezium, bending, and bending position. It is a figure which shows an example of the register mark which is printed in the 2nd adjustment mode. A diagram showing printed matter at the start and end of a job when the paper size changes during the job and the paper size is larger at the end of the job than at the start of the job in a conventional job that has undergone real-time adjustment. is there. It is a figure which shows the printed matter at the time of a job start and the time of the end of a job when the image position is adjusted in the edge reference mode of the second mode. It is a figure which shows the printed matter at the time of a job start and the time of the end of a job when the image position is adjusted in the central reference mode of the second mode. FIG. 5 is a diagram showing an example in which when the image position is adjusted in the second mode, the paper expands and contracts after the image is printed on the first surface of the paper to be printed first, and the magnification of the front and back images is deviated. It is a figure which shows the printed matter at the time of a job start and the time of the end of a job when the front and back positions are adjusted in the edge reference mode of the third mode. It is a figure which shows the printed matter at the time of a job start and the time of the end of a job when the front and back magnifications are adjusted in the edge reference mode of the third mode. It is a flowchart which shows the flow of the setting process executed by the control part of FIG. It is a flowchart which shows the flow of the image position adjustment processing executed by the control part of FIG. It is an image diagram of a bundle of paper that has been cut accurately. It is a figure which shows the image position at the start of printing and at the end of printing when printing is performed while adjusting at any time so that the distance between the paper edge and the registration marks at the four corners is constant using the paper bundle shown in FIG. 13A. It is an image diagram of a paper bundle in which the paper size increases as it goes down. It is a figure which shows the image position at the start of printing and at the end of printing when printing is performed while adjusting at any time so that the distance between the paper edge and the registration marks at the four corners is constant using the paper bundle shown in FIG. 14A.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[Structure of image forming apparatus]
First, the configuration of the image forming apparatus 100 in this embodiment will be described.
FIG. 1 is a functional block diagram showing a functional configuration of each part of the image forming apparatus 100, and FIG. 2 is a diagram showing mechanical components of each part of the image forming apparatus 100.

As shown in FIG. 1, the image forming apparatus 100 includes a control unit 101, a communication unit 102, an operation display unit 103, a storage unit 104, a paper feeding unit 105, a transport unit 106, a document reading unit 110, an image processing unit 140, and an image. It includes a forming unit 150, a fixing unit 160, an output reading unit 170, and an image analysis unit 180.

The control unit 101 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU of the control unit 101 reads a program according to the processing content from the ROM, develops it in the RAM, and centrally controls the operation of each unit of the image forming apparatus 100 in cooperation with the expanded program.

The communication unit 102 is composed of a communication control card such as a LAN (Local Area Network) card, and has various data with an external device (for example, a controller) connected to a communication network such as a LAN or WAN (Wide Area Network). To send and receive.

The operation display unit 103 includes a display device such as a liquid crystal display or an organic EL display, and an input device (operation unit) such as an operation key and a touch panel or a numeric keypad arranged on the screen of the display device. The operation display unit 103 displays various information on the display device, converts the user's input operation to the input device into an operation signal, and outputs the operation signal to the control unit 101.

The storage unit 104 is composed of, for example, a non-volatile semiconductor memory (so-called flash memory), a hard disk drive, or the like. The storage unit 104 stores various data including various setting information related to the image forming apparatus 100, job information (setting information and image data), and the like. For example, the storage unit 104 stores each setting information (adjustment mode, registration mark position setting, etc.) related to the second adjustment mode set in the setting process (see FIG. 11) described later. Further, the storage unit 104 stores the adjustment values (adjustment values for each of the front and back sides) of each adjustment item for image position adjustment.

The paper feed unit 105 feeds the paper stored in the paper feed tray according to the instruction from the control unit 101.
The transport unit 106 has a plurality of transport roller pairs such as a transport path and a resist roller pair, and transports the paper fed from the paper feed unit 105 in the image forming apparatus 100. Further, the transport unit 106 has a reversing mechanism 106a, and the front and back sides of the paper can be reversed and transported to the image forming unit 150.

The document reading unit 110 is configured to include an automatic document feeding device called an ADF (Auto Document Feeder), a document image scanning device (scanner), and the like, and reads an image of a document to generate image data.

Under the control of the control unit 101, the image processing unit 140 performs rasterization processing on the image data read by the document reading unit 110 and the PDL data transmitted from an external device (for example, a PC (Personal Computer)). ), Various image processing such as image position adjustment, gradation correction, color conversion, shading correction, and compression processing are performed on the image data input from). The image data subjected to these processes is input to the image forming unit 150.

The image forming unit 150 prints an image on paper based on the job setting information and the image data.
The fixing unit 160 fixes the image of the toner printed on the paper to the paper by heat and pressure.
In FIG. 2, the image forming unit 150 is shown as a so-called electrophotographic image forming unit, but the present invention is not limited to this, and for example, an inkjet type image forming unit may be used.

The output object reading unit 170 reads an image printed on paper by the image forming unit 150 and fixed by the fixing unit 160, and outputs the obtained read image data to the image analysis unit 180. The output object reading unit 170 is arranged on the downstream side of the image forming unit 150 and the fixing unit 160, and is configured to read an image during paper transfer. The output material reading unit 170 includes a reading unit 170a for reading an image on one side of the paper and a reading unit 170b for reading an image on the other side of the paper. Background members 171a and 171b are provided at positions facing each other of the reading unit 170a and the reading unit 170b with respect to the paper transport path. As shown in FIG. 3, the background members 171a and 171b have a black surface 1711 and a white surface 1712, and are rotated by a drive source (not shown) to switch the background when reading the paper to black or white. Can be done. Further, the reading size by the output material reading unit 170 is larger than the paper size, and the edges of the four sides of the paper can be read.

The image analysis unit 180 analyzes the scanned image data output by the output material reading unit 170, calculates the adjustment value of the position of the image to be printed on each of the front surface and the back surface of the paper, and outputs the adjusted value to the control unit 101.

[Image position adjustment operation]
Next, the operation of adjusting the image position in the image forming apparatus 100 will be described.
The image position adjustment adjusts the position of the image printed on the paper in the image forming apparatus 100, and has a first adjustment mode and a second adjustment mode.

The first adjustment mode is a mode in which the position of the image printed on the paper is adjusted by the image forming unit 150 before the main printing (before printing based on the job). Specifically, in the first adjustment mode, first, the image forming unit 150 sets the measurement patterns (called dragonflies) T1 to T4 shown in FIG. 4 at preset distances from the edges of the four sides of the paper on which the job is printed. (For example, 10 mm from the edge of the paper) is applied to the inside and printed on the front and back of the image forming unit 150 paper, the printed matter is read by the output reading unit 170, and the obtained read image data is analyzed by the image analysis unit 180. The positional relationship (distance) between the paper edge and the registration marks T1 to T4 is acquired. Then, the image analysis unit 180 calculates the adjustment values of a plurality of adjustment items on the front and back sides so that the distance between the paper edge and the register marks T1 to T4 (the register marks facing each paper edge) becomes a predetermined distance. , Stored in the storage unit 104. The first adjustment mode may be repeated a plurality of times in order to improve the measurement accuracy and stability. Alternatively, a plurality of printed matter to which the registration marks T1 to T4 are attached may be printed, adjustment values may be calculated for each, and the average value thereof may be used. At the time of main printing, the control unit 101 controls the image processing unit 140, the image forming unit 150, the conveying unit 106, and the like based on the adjustment value stored in the storage unit 104 to adjust the position of the image to be printed on the paper. To do.

The plurality of adjustment items calculated in the first adjustment mode include vertical and horizontal magnifications, vertical and horizontal image shifts, rotation, skew, vertical trapezium, horizontal trapezium, bending, and bending position. For each of these adjustment items, the adjustment value can be obtained independently. Among the above adjustment items, the image positions at the four corners can be adjusted by adjusting the adjustment items of magnification, image shift, rotation, skew, vertical trapezium, and horizontal trapezium. Further, the bending and the bending position are for adjusting the distortion of the image, and by using these in combination, more advanced image position adjustment is possible.

FIG. 5A shows a range of adjustment values and an adjustment image for each adjustment item of vertical magnification, horizontal magnification, vertical image shift, and left / right image shift. FIG. 5B shows a range of adjustment values and an adjustment image for each adjustment item of rotation, skew, vertical trapezium, horizontal trapezium, bending, and bending position. The thick arrows A in FIGS. 5A and 5B indicate the paper transport direction, the solid line indicates the paper, the dotted line indicates the target image position, the hatching indicates the current image position, and the thin arrow indicates the adjusted image. Indicates the direction of movement. Regarding the image shift in FIG. 5A, since it is difficult to see both the current image position and the target image position, both are represented as the same, and only the direction in which the image moves by adjustment is shown. Further, in FIG. 5B, the solid line indicating the paper is omitted.

In the present embodiment, in the first adjustment mode, the paper on which the dragonflies T1 to T4 are printed is read by the output reading unit 170, and the obtained read image data is analyzed by the image analysis unit 180. Although it is described as automatically acquiring the adjustment value of each adjustment item shown in 5A and FIG. 5B, the adjustment of each adjustment item determined by the user visually observing the paper on which the registration marks T1 to T4 are printed is described. The input of the value may be received from the operation display unit 103, and the value of each adjustment value may be acquired. Further, the document reading unit 110 may be configured to read and analyze the paper on which the registration marks T1 to T4 are printed. In this case, since the document reading unit 110 is made for the copying function, the background is white. For this purpose, in order to clearly read the paper edges, for example, a dark background paper is superimposed on the paper on which the registration marks T1 to T4 are printed, and the front and back sides and top and bottom of the printed paper are arranged so that the paper edges can be read properly. It may be replaced and read and analyzed as appropriate (for example, 4 times).

The second adjustment mode is a mode in which the position of the image printed on the paper is adjusted by the image forming unit 150 during the main printing (so-called real-time adjustment mode). Specifically, in the second adjustment mode, first, the register marks T11 to T14 shown in FIG. 6 are set at preset distances from the four corners of the paper on which the job is printed (for example, the paper edges of the two sides constituting the four corners of the paper). The printed matter is printed on paper by the image forming unit 150 by applying 3 mm) to each of the inner four corners, the printed matter is read by the output reading unit 170, and the obtained read image data is analyzed by the image analysis unit 180 and used on the paper. The distance between the edge and the registration marks T11 to T14 (the registration marks facing each paper edge) is acquired. Then, the image analysis unit 180 calculates and updates the adjustment value of each adjustment item to be acquired based on the acquired distance between the paper edge and the registration marks T11 to T14. The control unit 101 controls the image processing unit 140, the image forming unit 150, the conveying unit 106, and the like based on the updated adjustment value to adjust the position of the image to be printed on the paper in the subsequent printing.
The preset distance described above is smaller in the second adjustment mode because the image of the user content printed together with the registration marks T11 to T14 is used in the second adjustment mode. This is to prevent the user contents from overlapping with T11 to T14. Further, in the vicinity of the edge of the paper, for example, auxiliary information for the printing operator to confirm the printing conditions and the like is often printed. If these and the registration marks T11 to T14 overlap, the second adjustment mode may not operate correctly. Therefore, a process of whitening the image information around the registration marks (in a state where toner is not printed) may be added.

In the second adjustment mode, in the second adjustment mode, registration marks T11 to T14 independent at the four corners are used at the four corners as shown in FIG. 6 in order to omit bending and adjustment of the bending position for simplification of processing. As in the first adjustment mode, the registration marks T1 to T4 may be used to bend and adjust the bending position.

Here, in the real-time adjustment performed during the main printing in the conventional image forming apparatus, the image is set so that the distance between the paper edge and the register marks T1 to T4 becomes a predetermined distance, as in the first adjustment mode described above. I was adjusting the position.

In FIG. 7, in the conventional job in which real-time adjustment was performed, the paper bundle used for printing by the job was cut incorrectly, so that the paper size changed during the job and the time at the end of the job was higher than the time at the start of the job. It is a figure which shows the printed matter at the time of job start time (printing start time) and job end time point (printing end time) when the paper size becomes large. The dotted line on the printed matter at the end of the job shown in FIG. 7 indicates the paper size at the start of the job (the same applies to FIGS. 8A to 10B). In the printed matter output by the job, an image based on the job is printed inside the register marks T11 to T14, but the images are omitted in FIGS. 7 to 10B for the sake of simplicity.

As described above, in the conventional real-time adjustment, the image magnification is adjusted so that the distance between the paper edge and the registration marks at the four corners is constant. Therefore, when the paper size changes during the job, as shown in FIG. The image size will change accordingly. Then, for example, when the bundle of paper after printing is cut based on the position at the start of the job, the printed matter at the end of the job may have a problem such as the image being cut off after cutting.

Therefore, in the second adjustment mode of the present embodiment, in addition to the first mode in which the adjustment equivalent to the conventional real-time adjustment is performed, the second mode in which the magnification adjustment is restricted, the magnification adjustment is restricted, and the magnification adjustment is restricted. It has a third mode for adjusting the front-back difference caused by this. Further, each of the second mode and the third mode includes an edge reference mode in which the position of the image is adjusted so that the distance between the image printed on at least one side of the paper and a specific paper edge is a predetermined distance. , Any of the central reference modes for adjusting the position of the image so that the position of the image printed on the paper is located at the center of the paper can be selected by the operation display unit 103.

FIG. 8A is a diagram showing printed matter at the time of job start and the time of job end when the image position is adjusted in the edge reference mode of the second mode. FIG. 8A shows an example in which edges E1 and E4 are designated as specific paper edges.
In the edge reference mode of the second mode, in order to limit the magnification adjustment and adjust the image position so as to be a predetermined distance from a specific paper edge (E1, E4 in FIG. 8A), as shown in FIG. 8A. In addition, when the post-process is set up so as to cut the sides (E3, E2) facing the specific paper edge, the image positions in the printed matter at the time of starting the job and the time of ending the job can be easily aligned.

FIG. 8B is a diagram showing printed matter at the time of job start and the time of job end when the image position is adjusted in the central reference mode of the second mode.
In the center reference mode of the second mode, the image is positioned at the center of the paper as shown in FIG. 8B in order to limit the magnification adjustment and adjust the image position so that the image position is evenly positioned from each paper edge. Can be made to.
For example, when there is no cutting in the post-process and it is necessary to finish the image size as specified, it may be preferable to adjust the image position in this adjustment mode.

When the image position is adjusted in the second mode, as shown in FIG. 9, the paper expands and contracts after printing the image on the first side (here, the front side) of the paper to be printed first, and the front and back sides are adjusted. The magnification of the image may shift. In FIG. 9, the solid line dragonfly represents the front surface dragonfly, and the dotted line dragonfly represents the back surface dragonfly (the same applies to FIGS. 10A and 10B). The third mode is a mode in which the difference between the front and back sides can be adjusted when the magnification of the front and back images is deviated by limiting the magnification adjustment in this way.

As a method for adjusting the front-to-back difference in the third mode, the image forming unit 150 adjusts the magnification of the image of the surface to be printed later with the image of the surface to be printed first as a reference. A method of adjusting the front-back difference of the image printed on the front and back (called front-back magnification adjustment) and the misalignment of the image of the side printed later with respect to the image of the side printed first are the minimum on average at the four corners. There is a method of adjusting the position of the image on the surface to be printed later (called front / back position adjustment). Which adjustment method is to be adopted can be selected by the operation display unit 103.

FIG. 10A is a diagram showing printed matter at the time of job start and the time of job end when the front and back positions are adjusted in the edge reference mode of the third mode.
FIG. 10B is a diagram showing printed matter at the time of job start and the time of job end when the front and back magnifications are adjusted in the edge reference mode of the third mode.
As shown in FIGS. 10A and 10B, in the third mode, even if the paper expands and contracts between printing on the front surface and the back surface, the image positional relationship between the front and back surfaces can be kept good.

In addition, in FIGS. 7 to 10B, the case where the paper becomes larger as the printing progresses is described, but conversely, the paper may become smaller as the printing progresses. In this case, when the registration marks T11 to T14 are printed in the vicinity of the paper edge, it can be assumed that the distance between one of the registration marks and the paper edge becomes closer as the printing progresses, and the registration marks may protrude from the paper edge. In this case, it may not be possible to adjust the correct image position. Therefore, in the present embodiment, when the magnification adjustment is restricted in the second adjustment mode (that is, in the case of the second mode and the third mode), the distance between the registration marks T11 to T14 and the paper edge determines the magnification adjustment. It is possible to adjust the positions of the register marks T11 to T14 so as to be larger than in the case where there is no limitation. Whether or not to adjust the positions of the registration marks T11 to T14 can be selected by the operation display unit 103.

FIG. 11 is a flowchart showing a flow of setting processing for setting various setting items such as an adjustment mode in the above-mentioned image position adjustment. The setting process shown in FIG. 11 is executed in collaboration with the CPU of the control unit 101 and the program stored in the RAM.

First, the control unit 101 causes the operation display unit 103 to display a selection button for selecting whether or not to limit the execution of the magnification adjustment. When the selection button for selecting not to restrict the execution of the magnification adjustment is selected by the operation of the user's operation display unit 103 (step S1; NO), the control unit 101 sets the adjustment mode to the first mode (step). S2), the setting process is completed.

In step S1, when the selection button for selecting to limit the execution of the magnification adjustment by the operation of the user's operation display unit 103 is selected (step S1; YES), does the control unit 101 perform the front-back difference adjustment? A selection button for selecting whether or not to use is displayed on the operation display unit 103. When the selection button for selecting not to perform the front-back difference adjustment is selected by the operation of the user's operation display unit 103 (step S3; NO), the control unit 101 sets the adjustment mode to the second mode (step S4). ), The process proceeds to step S8.

When the selection button for selecting to perform the front-back difference adjustment is selected by the operation of the user's operation display unit 103 (step S3; YES), the control unit 101 selects whether or not to perform the front-back magnification adjustment. The selection button for this is displayed on the operation display unit 103. When the selection button for selecting not to perform the front / back magnification adjustment is selected by the operation of the user's operation display unit 103 (step S5; NO), the control unit 101 changes the adjustment mode to the third mode (front / back position adjustment). The setting (step S6) is performed, and the process proceeds to step S8.
When the selection button for selecting to perform the front / back magnification adjustment is selected by the operation of the user's operation display unit 103 (step S5; YES), the control unit 101 changes the adjustment mode to the third mode (front / back magnification adjustment). The setting (step S7) is performed, and the process proceeds to step S8.

In step S8, the control unit 101 causes the operation display unit 103 to display a selection button for selecting whether or not to adjust the register mark position. When the selection button for selecting to adjust the register mark position is selected by the operation of the user's operation display unit 103 (step S8; YES), the control unit 101 presets the register mark position in the second adjustment mode. Set the direction away from the reference position by a predetermined distance from the paper edge (step S9), and proceed to step S11.
When the selection button for selecting not to adjust the register mark position is selected by the operation of the user's operation display unit 103 (step S8; NO), the control unit 101 presets the register mark position in the second adjustment mode. The reference position is set (step S10), and the process proceeds to step S11.

In step S11, the control unit 101 causes the operation display unit 103 to display a selection button for selecting whether or not to align the image position with a specific paper edge. When the selection button for selecting to align the image with a specific paper edge is selected by the operation of the user's operation display unit 103 (step S11; YES), the control unit 101 sets the edge to the currently set adjustment mode. The reference mode is additionally set (step S12), and the setting process is completed.
When the selection button for selecting not to align the image with a specific paper edge is selected by the operation of the user's operation display unit 103 (step S11; NO), the control unit 101 is set to the currently set adjustment mode. The central reference mode is additionally set (step S13), and the setting process is completed.

The specific paper edge may be automatically set by the control unit 101 according to, for example, a setting at the time of printing, a paper passing path, and a post-process after printing.
For example, after printing, there are a face-up in which the first page is discharged with the top page facing and a face-down in which the paper is discharged with the bottom surface facing. In the case of performing after passing paper, if a specific paper edge direction (side) is set for the convenience of the post-process, the specific paper edge direction in the image read by the output reading unit 170 is face-up / face. It depends on the down setting. Further, when an online cutting machine, a stapler, a bookbinding machine such as a saddle binder is provided in the post-process, it can be easily imagined that the paper edge to be set as a specific paper edge differs depending on the subsequent device. Therefore, it is preferable that the control unit 101 automatically sets a specific paper edge according to the configuration of the subsequent device.

Further, in the above setting process, the case where the user makes various settings related to the image position adjustment on the operation panel has been described as an example, but the administrator is provided with the image position adjustment setting function on the screen limited to the administrator. Only can be set, or a serviceman who maintains the image forming apparatus 100 may open a screen of a dedicated maintenance mode and set it. Alternatively, it may be set by a mechanism such as a DIP switch or an electric mechanism.

Hereinafter, the image position adjustment process executed by the control unit 101 based on the setting by the above setting process will be described.
FIG. 12 is a flowchart showing the flow of the image position adjustment process. The image position adjustment process is executed by the control unit 101 when a job is selected with the image position adjustment set and a print start instruction is instructed.

First, the control unit 101 adjusts the image positions of the front and back sides in the first adjustment mode (step S21).
Since the image position adjustment in the first adjustment mode is as described above, the description is incorporated.
The control unit 101 switches the surface of the background members 171a and 171b facing the paper in the output reading unit 170 to the black surface 1711 or the white surface 1712 depending on the color of the paper used (in the case of white paper, the black surface). 1711 faces each other, the white side 1712 faces each other in the case of black paper, and in the case of other paper colors, an easy-to-read or readable background member color is appropriately selected. In the case of black paper, printing is performed on the paper. The color tone of the dragonfly may be formed of a color material that can be easily distinguished from the paper, for example, white toner), so that the output reading unit 170 can read the four sides of the paper edge.

Next, the control unit 101 starts printing based on the job (step S22), and prints each page of the job while adjusting the image position in the second adjustment mode.

That is, first, the control unit 101 adds registration marks T11 to T14 for measuring the distance from the paper edge to the margin portion of the image of the print target page (step S23).
Here, the control unit 101 adds registration marks T11 to T14 based on the registration mark position setting information stored in the storage unit 104.

Next, the control unit 101 controls the image processing unit 140, the image forming unit 150, the conveying unit 106, and the like based on the adjustment values of the adjustment items stored in the storage unit 104, and prints the image on the paper. The position is adjusted, and the images to which the registration marks T11 to T14 are attached are printed on the paper and fixed by the fixing portion 160 (step S24). When performing double-sided printing, the control unit 101 controls the transport unit 106 and the image forming unit 150 to perform double-sided printing.

Next, the control unit 101 causes the output material reading unit 170 to read the printed paper (printed matter) and acquires the scanned image data including the paper edge (step S25).

Next, the control unit 101 analyzes the scanned image data acquired by the output material reading unit 170 by the image analysis unit 180 to acquire the distance between the paper edge and the register marks T11 to T14 (step S26).

Next, the control unit 101 calculates and updates the adjustment value of each adjustment item to be acquired based on the distance between the paper edge and the register marks T11 to T14 in the adjustment mode set by the image analysis unit 180. (Step S27), the process proceeds to step S28.

For example, when the adjustment mode is set to the first mode, the magnification, image shift, rotation, and so on so that the distance between the paper edge and the register marks T11 to T14 (the register marks facing each paper edge) becomes a predetermined distance. The adjustment values of the adjustment items of the skew, the vertical trapezium, and the horizontal trapezium are calculated, and these adjustment values in the storage unit 104 are updated.

For example, when the adjustment mode is set to the edge reference mode of the second mode, the image shift, rotation, skew, and so on so that the distance between the specific paper edge and the register mark facing the specific edge becomes a predetermined distance. The adjustment values of the trapezium and trapezium adjustment items are calculated, and these adjustment values in the storage unit 104 are updated. Magnification is not adjusted.
For example, when the adjustment mode is set to the center reference mode of the second mode, image shift, rotation, skew, and vertical trapezium so that the register marks T11 to T14 are evenly positioned (in the center of the paper) from the paper edge. , The adjustment values of the horizontal trapezium adjustment items are calculated, and these adjustment values in the storage unit 104 are updated. Magnification is not adjusted.

For example, when the adjustment mode is set to the third mode (front and back position adjustment), first, among the previously printed register marks T11 to T14 on the first surface, the position of the register mark facing a specific paper edge is the relevant position. The adjustment values of the adjustment items of the image shift, rotation, skew, vertical trapezium, and horizontal trapezium are calculated so as to be a predetermined distance from the specific paper edge, and these adjustment values in the storage unit 104 are updated. Magnification is not adjusted. Next, image shift, rotation, skew, and so on so that the positional deviation between the trapeziums T11 to T14 on the second surface printed later and the adjusted register marks T11 to T14 on the first surface are minimized on average at the four corners. The adjustment values of the vertical trapezium and horizontal trapezium adjustment items are calculated, and these adjustment values in the storage unit 104 are updated. Magnification is not adjusted.

In the present embodiment, in the adjustment mode that does not limit the magnification adjustment, the adjustment values of the adjustment items of the magnification, the image shift, the rotation, the skew, the vertical trapezium, and the horizontal trapezium are calculated, and the adjustment mode that limits the magnification adjustment is performed. In, the adjustment values of the adjustment items of the image shift, rotation, skew, vertical trapezium, and horizontal trapezium are calculated, but the adjustment items with less deviation may be omitted. Further, the user may be configured to set which adjustment item to calculate the adjustment value from the operation display unit 103.

Further, in the second adjustment mode, the printed paper is read, the distance between the registration marks T11 to T14 and the paper edge is measured, the adjustment value is calculated based on the measurement result, and the calculated adjustment value is to be printed from now on. Applies to images. Therefore, a delay of, for example, several to several tens of sheets occurs from the printing used for the measurement to the printing to which the adjusted value is applied. Therefore, the control unit 101 may control the degree of updating of the adjustment value so as not to adjust too much.

Further, when calculating each adjustment value, the image analysis unit 180 saves the adjustment values for the most recent multiple adjustments (for example, 20 adjustments), and makes adjustments calculated based on the current scanned image data. It is preferable to calculate the adjustment value by taking the trend into consideration by using the value and the adjustment value for the most recent multiple times. Thereby, the adjustment accuracy can be improved.

In step S28, the control unit 101 determines whether or not printing of all pages has been completed (step S28). If it is determined that printing of all pages has not been completed (step S28; NO), the control unit 101 returns to step S23 and repeatedly executes the processes of steps S23 to S28 for the next page. When it is determined that printing of all pages is completed (step S28; YES), the control unit 101 ends the image position adjustment process.

Hereinafter, a modification of the image position adjustment process will be described.
[Modification 1]
In the flowchart shown in FIG. 12, the case where the adjustment in the first adjustment mode is performed before the execution of the job is shown, but the adjustment in the first adjustment mode is at least the case of the job immediately after the paper bundle is replaced. It may be done before execution, and it is not necessary to perform the first adjustment mode before each job is executed. However, if the user resets the mode setting in the second adjustment mode between jobs, or if the adjustment value is updated by adjusting only the adjustment mode that was set up to that point, the newly set adjustment is performed. Since the adjustment value in the mode is not retained, it is necessary to reset the adjustment value and readjust the adjustment in the first adjustment mode before starting the next job.
In order to avoid this and smoothly switch the adjustment mode in the second adjustment mode without performing the adjustment in the first adjustment mode, the image analysis unit 180 is set to at least 2 in the second adjustment mode. It is preferable that the adjustment values in the two adjustment modes are calculated in parallel and stored in the storage unit 104. For example, the calculation of the adjustment value in the adjustment mode set by the user and the calculation of the adjustment value in the first mode in which the magnification adjustment is not restricted are performed in parallel, and each adjustment value is stored in the storage unit 104. I will do it. Alternatively, the adjustment mode to be calculated in parallel may be set from the operation display unit 103, and the adjustment value in the set adjustment mode may be calculated and stored in parallel with the adjustment value in the actual adjustment mode. ..
In this case, the print result when the adjustment value is updated is actually obtained only in the currently set adjustment mode, so the adjustment value in the adjustment mode for calculating the adjustment value in parallel is currently set. It may be calculated and updated as a difference value from the adjustment value of the adjustment mode.

[Modification 2]
When the cutting process is performed in the subsequent process, it is preferable that the cutting position can be easily adjusted. When the image position is adjusted so that the image is arranged at a predetermined distance from the specific paper edge by the above image position adjustment process, the side facing the specific paper edge is first cut to cut the paper of the printing paper. Even if there are variations in the paper size of the bundle, paper cutting and cutting processing can be easily performed.
Here, since it is necessary for the user to correctly grasp the direction of a specific paper edge when performing the cutting process, for example, in the image position adjustment process, for example, the first cutting direction (side) can be easily identified. Cutting in the direction (side) to be cut first Change the design of the dragonfly, add a specific mark, and cut the cutting direction and cutting in a form that can be seen on the top surface of the print job bundle, apart from the actual printed matter based on the job. Processing such as printing and superimposing sheets on which post-process information indicating the method is printed may be performed. Further, the image forming apparatus 100 transmits the post-process information to the display device installed in front of the cutting machine, and the image forming apparatus 100 transmits the post-process information to the display device installed in front of the cutting machine via the server. Controls may be combined.

[Modification 3]
In the above embodiment, the image position is adjusted by defining a specific paper edge and adjusting the distance between the edge and the register mark. However, a specific register mark is defined and a paper edge close to the edge is defined. Similar processing results can be obtained by adjusting the distance between the paper edge and the register marks. Alternatively, the paper edges and registration marks that are not used for adjusting the distance between the paper edges and the registration marks may be specified.

[Modification example 4]
In the image position adjustment of the above embodiment, for example, a conventional piece that detects the paper passing position of the paper before printing and calculates and adjusts the paper position and the offset correction amount of the printed image based on the detected information. Other correction processing such as deviation correction may be used in combination. For example, a mechanism is generally used in which a sensor for reading the paper passing position of the paper edge before printing is provided and the offset of the paper is corrected immediately before printing based on the result. For example, the sensor is used for the paper edge. When only one side (for example, the front side) is detected, it can be expected that the image position is controlled more stably with respect to the front side of the paper edge. In such a case, the edge side read by the sensor may be set as the specific paper edge, or a message recommending the setting may be displayed on the operation screen. Similarly, when there is a separate mechanism for regulating the paper position, the paper edge in which the relationship between the image position and the paper edge is easily stabilized by the regulation can be set or recommended as the specific paper edge.

[Modification 5]
The image forming apparatus 100 of the above embodiment has been described as having a configuration having a plurality of adjustment modes in the second adjustment mode, and the user selects which adjustment mode to execute the adjustment, but any one of the adjustments is made. The mode may be built into the image forming apparatus.

[Modification 6]
Further, in the above embodiment, the image analysis unit 180 analyzes the image data of the printed paper read by the output material reading unit 170 to calculate the adjustment value, and the control unit 101 determines the image forming unit based on the calculated adjustment value. Although it was decided to control each part including 150 to adjust the image position, the control unit 101 may calculate the adjustment value by analyzing the read image data of the printed paper.
Alternatively, the adjustment value calculated by the image analysis unit 180 is transmitted to an external device (controller or server) by the communication unit 102, and the position on the paper is adjusted according to the received adjustment value in the external device, and the margin. A paper image image containing the above may be generated and transmitted to the image forming apparatus 100. Then, the image forming apparatus 100 may output the printed matter whose image position is adjusted by printing the received image as it is without adjusting the position. Alternatively, the measurement result of the distance between the paper edge and the register mark may be transmitted to the external device by the communication unit 102, and the adjustment value may be calculated by the external device.

As described above, according to the image forming apparatus 100, the control unit 101 adjusts the position of the image printed on the paper by the image forming unit 150 before the main printing as the operation mode of the image position adjusting. The adjustment mode and the second adjustment mode for adjusting the position of the image printed on the paper by the image forming unit 150 during the main printing are provided, and the first adjustment is performed when operating in the second adjustment mode. Of the adjustment items performed in the mode, at least the performance of magnification adjustment is restricted.
Therefore, even when the cutting accuracy of the paper bundle used for printing is not sufficient, the image magnification deviation through the job can be reduced, and the image misalignment between the papers after cutting in the subsequent process is small. It is possible to obtain good printing results.

Further, the second adjustment mode has a first mode that does not restrict the execution of the magnification adjustment and a second mode that restricts the execution of the magnification adjustment, and is configured so that the user can select the first mode or the second mode. Therefore, it is possible to match the image with the outer shape of the paper without limiting the magnification.

In addition, the second adjustment mode has a third mode that limits the execution of magnification adjustment and also adjusts the difference between the front and back of the image printed on the front and back of the paper. Even when the paper stretch ratio changes, it is possible to obtain a printing result with a small difference between the front and back sides.

Further, among the plurality of adjustment modes included in the second adjustment mode, each of the adjustment modes for limiting the execution of the magnification adjustment specifies the image and the paper to be printed on at least one side of the paper by the image forming unit 150. The adjustment mode for adjusting the position of the image so that the distance from the edge of the image is a predetermined distance, and the position of the image is adjusted so that the position of the image printed on the paper by the image forming unit 150 is located at the center of the paper. One of the adjustment modes can be selected. Therefore, by selecting the adjustment mode that adjusts the position of the image so that the distance to the specific edge is a predetermined distance, the relationship between the image position and the specific edge of the paper can be maintained throughout the job. The cutting process in the post-process becomes easy. The image position can also be set to the center of the paper.
Here, the above-mentioned maintenance of the relationship between the image position and the specific edge of the paper may be configured to maintain a predetermined distance, or the relationship when printing is started in the second adjustment mode. It may be configured to maintain (distance). The selection of this configuration may be predetermined or may be in accordance with the contents set by means such as an operation panel.
Further, in the above description, as an example of image position adjustment, the magnification and the image position are specifically described as control targets, but the present invention is not limited thereto. For example, the rotation image position adjustment shown in FIG. 5B is usually adjusted so that there is no inclination with respect to the outer shape of the paper that approximates a rectangle, but when the edge of the paper is specified, the edge of the paper is adjusted. It may be configured to be adjusted so that there is no tilt.

Further, when the control unit 101 makes an adjustment in the second adjustment mode, the control unit 101 calculates the adjustment values of at least two adjustment modes included in the second adjustment mode and stores them in the storage unit 104, so that another adjustment is made. Switching to the mode becomes easy.

Further, when the control unit 101 limits the execution of the magnification adjustment in the second adjustment mode, the distance between the measurement pattern printed on the paper by the image forming unit 150 and the edge of the paper limits the execution of the magnification adjustment. Adjust the position of the measurement pattern so that it is larger than when it is not. Therefore, the cutting accuracy of the paper bundle is poor, and it is possible to prevent the measurement pattern from protruding from the paper edge when the paper becomes smaller as the job progresses.

The description in the above embodiment is a preferable example of the image forming apparatus according to the present invention, and is not limited thereto.

Further, in the above description, an example in which a non-volatile semiconductor memory or a hard disk is used as a computer-readable medium in which a program for executing each process is stored is disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. Further, a carrier wave may be applied as a medium for providing program data via a communication line.

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

100 Image forming device 101 Control unit 102 Communication unit 103 Operation display unit 104 Storage unit 105 Paper feeding unit 106 Transport unit 110 Document reading unit 140 Image processing unit 150 Image forming unit 160 Fixing unit 170 Output material reading unit 180 Image analysis unit

Claims (9)

An image forming means for forming an image on paper,
An image position adjusting means for adjusting the position of an image printed on the paper by the image forming means based on the positional relationship between the edge of the paper and the measurement pattern printed on the paper by the image forming means.
An image forming apparatus equipped with
The image position adjusting means is printed on the paper by the image forming means during the main printing and a first adjustment mode for adjusting the position of the image printed on the paper by the image forming means before the main printing. It has a second adjustment mode for adjusting the position of the image, and limits the execution of at least the magnification adjustment among the adjustment items performed in the first adjustment mode when operating in the second adjustment mode. Image forming device. The second adjustment mode has a first mode that does not limit the execution of the magnification adjustment and a second mode that limits the execution of the magnification adjustment.
The image forming apparatus according to claim 1, further comprising a selection means for selecting the first mode or the second mode. The image forming apparatus according to claim 1 or 2, wherein the second adjustment mode has a third mode for limiting the execution of the magnification adjustment and further adjusting the front-back difference of the image printed on the front and back of the paper. In the third mode, the front and back of the image printed on the front and back of the paper are adjusted by adjusting the magnification of the image of the surface to be printed later with reference to the image of the surface to be printed first in the image forming means. The image forming apparatus according to claim 3, wherein the difference is adjusted. In the third mode, the position of the surface to be printed later is minimized on average at the four corners with respect to the image of the surface to be printed first in the image forming means. The image forming apparatus according to claim 3, wherein the position of the image is adjusted. Of the plurality of adjustment modes included in the second adjustment mode, each of the adjustment modes for limiting the execution of the magnification adjustment includes an image printed on at least one side of the paper by the image forming means and the paper. An adjustment mode that adjusts the position of the image so that the distance to a specific edge is a predetermined distance, and the position of the image so that the position of the image printed on the paper by the image forming means is located in the center of the paper. The image forming apparatus according to any one of claims 1 to 5, wherein any of the adjustment modes for adjusting the image can be selected. Claims 2 to 2 for which, when the image position adjusting means performs adjustment in the second adjustment mode, the adjustment values of at least two adjustment modes included in the second adjustment mode are calculated and stored in the storage means. The image forming apparatus according to any one of 6. When limiting the execution of the magnification adjustment in the second adjustment mode, as compared with the case where the distance between the measurement pattern printed on the paper by the image forming means and the edge of the paper does not limit the execution of the magnification adjustment. The image forming apparatus according to any one of claims 1 to 7, further comprising a measurement pattern adjusting means for adjusting the position of the measurement pattern so as to become larger. An image position adjustment method for adjusting the position of an image printed on paper by the image forming means based on the positional relationship between the edge of the paper and the measurement pattern printed on the paper by the image forming means.
The first adjustment mode for adjusting the position of the image printed on the paper by the image forming means before the main printing, and the first adjustment mode for adjusting the position of the image printed on the paper by the image forming means during the main printing. An image position adjustment method having two adjustment modes and limiting at least the execution of magnification adjustment among the adjustment items performed in the first adjustment mode when operating in the second adjustment mode.

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