JP2016201652A - Image forming apparatus and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus and an image forming method with which an angle can be properly corrected in composition of an inclination of an image occurring during document reading and an additional image.SOLUTION: An image forming apparatus comprises a reading part that reads a document image, and a control part that performs image data processing. The control part acquires image inclination information on a read image, rotates an additional image to have the same inclination according to the image inclination information, composes the rotated additional image with the read image, and rotates to correct the composed image on the basis of the image inclination information to obtain image data for printing.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus and an image forming method for performing printing based on image data.

In an image forming apparatus that forms an image based on image data, an original is read by a flatbed scanner, image data is generated, and is used for printing. Further, a document having a document conveying device that automatically conveys a document and can read the document can be read while the document is conveyed by the document conveying device. In both cases, since the image is read line by line, if the original is read obliquely or if the reading unit is attached obliquely, the read image is distorted.
On the other hand, in Patent Document 1, it is possible to determine the amount of image tilt using a scanner and a main body installation function, and to correct the image tilt.
Further, in Patent Document 2, it is possible to read a plurality of originals with one scan and to correct the inclination of each original by image processing.

JP 2006-237752 A Japanese Patent Laying-Open No. 2005-057603 JP 09-284545 A

By the way, some image forming apparatuses are capable of printing by adding an additional image such as a stamp, numbering, noble, date, etc. to a document image.
In this case, an image with a different tilt amount is superimposed on the scanned image (for example, a stamp is created by the CPU, so the tilt amount is 0, and another tilt amount is used for registered overlays, etc.), and the output tilt amount is added during output. Will be corrected. For this reason, only the superimposed images have different inclination amounts. This is because the read image is tilted and stored in the memory so as to be read by the document conveying device or the scanner, but usually the page date is not tilted.
If the tilt correction is performed on the read image and the image is combined after setting the tilt amount to 0, this problem does not occur, but a dedicated tilt correction circuit is loaded on the read image, resulting in an increase in cost. End up.

  Further, Patent Document 3 proposes a method of adjusting the size and angle (in units of 90 degrees) when overlapping with a form image. However, this method can only adjust the angle in units of 90 degrees, and cannot cope with the inclination of the original image generated at the time of reading.

  The present invention has been made against the background of the above circumstances, and provides an image forming apparatus and an image forming method capable of appropriately performing angle correction in composition of an image inclination generated when a document is read and an additional image. Objective.

That is, among the image forming apparatuses of the present invention, the first form is
A reading unit for reading a document image;
A control unit that performs image data processing,
The control unit obtains image tilt information of the read image, rotates the additional image so as to have the same tilt according to the image tilt information, and combines the rotated additional image with the read image to be combined. The printed image data is obtained by performing rotation correction on the obtained image based on the image tilt information.

An image forming apparatus according to another aspect of the present invention includes a document conveying device that conveys the document image and allows the reading unit to read the image forming apparatus according to another aspect of the present invention.
The document conveying device has an inclination detection unit that detects an inclination angle of the document being conveyed,
The image forming apparatus according to claim 1, wherein the control unit acquires the image tilt information based on a detection result of the tilt detection unit.

  An image forming apparatus according to another aspect of the present invention is characterized in that, in the above-described other aspect of the present invention, the control unit acquires the inclination information of the read image for each of the originals.

  In another form of the image forming apparatus according to the present invention, in the other form of the present invention, the control unit uses the information acquired in the first sheet of the original to detect the inclination information of the read image on all pages of the original. It is characterized by being shared by.

In another form of the image forming apparatus of the present invention, the image inclination information of the read image is stored in the storage unit as a fixed value in the present invention of the other form,
The control unit acquires image tilt information from a fixed value stored in the storage unit.

  In another form of the image forming apparatus of the present invention, in the above aspect of the present invention, the control unit acquires sheet inclination information of a sheet conveyed in preparation for printing, and the sheet inclination information is included in the image inclination information. Is added to perform the rotation correction.

  In another form of the image forming apparatus according to the present invention, the control unit has a function of adjusting the image quality of the image data before the image quality adjustment is performed on the read image. The rotated additional image is synthesized, the image quality adjustment is performed on the synthesized image, and then the rotation correction is performed.

  In another form of the image forming apparatus according to the present invention, in the case of the other form of the present invention, when the additional image is a single color and has a maximum density, the control unit rotates the read image to an image after adjusting the image quality. The additional image is synthesized, and then rotation correction is performed.

  An image forming apparatus according to another aspect of the present invention is characterized in that, in the above-described other aspect of the present invention, the control unit performs an expansion process on the image data of the read image before the image quality adjustment. .

  An image forming apparatus according to another embodiment of the present invention is characterized in that, in the present invention of another embodiment, when the additional image rotated before the image quality adjustment is combined, the additional image is combined after the decompression process. To do.

  In another form of the image forming apparatus according to the present invention, in the case of the other form of the present invention, when the additional image is the same image for each page and the image size is equal to or larger than a predetermined value, the image forming apparatus is based on inclination information determined first. The additional image is rotated and then combined with the original image.

  In another form of the image forming apparatus according to the present invention, in the case of the other form of the present invention, when the additional image is different depending on a page and the image size is equal to or larger than a predetermined value, Before the tilt information is acquired, the additional image is rotated and synthesized with the original image.

The image forming method of the present invention is an image forming method for performing printing based on image data.
A reading process for reading a document image;
A data processing step for performing data processing of the image data,
In the data processing step, image tilt information of a document image is acquired, an additional image is rotated so as to have the same tilt based on the image tilt information, and the rotated additional image is combined with the read image. And performing control to obtain image data for printing by performing rotation correction on the image synthesized based on the image tilt information.

  There is an effect that angle correction can be appropriately performed in the composition of the image tilt and the additional image generated when the document is read.

1 is a diagram illustrating a mechanical outline of an image forming apparatus according to an embodiment of the present invention. Similarly, it is a figure which shows an electrical block diagram. Similarly, it is a diagram showing an arrangement state of the document image tilt detection sensor. Similarly, it is a diagram for explaining a time chart of detection data by an original image inclination detection sensor and a calculation method of inclination. Similarly, it is the schematic which shows the hardware constitution at the time of performing image correction. Similarly, it is a flowchart showing a rotation procedure of an additional image at the time of printing using the additional image. Similarly, it is a ladder diagram showing a procedure when performing image correction. Similarly, it is a figure explaining the condition of paper inclination.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
A mechanical outline of an image forming apparatus 1 according to an embodiment of the present disclosure will be described mainly with reference to FIG.
The image forming apparatus 1 is provided with an automatic document feeder (ADF) 13 on the upper side of the image forming apparatus main body 10, and a document fed by the automatic document feeder (ADF) 13 is a scanner 130. Image reading is possible. The document can be read by the scanner 130 on the platen glass. An automatic document feeder (ADF) 13 corresponds to the document feeder of the present invention. The scanner 130 corresponds to the reading unit of the present invention.

  In addition, an operation display unit 140 is installed on the upper side of the image forming apparatus main body 10 at a location where the platen glass is not located. The operation display unit 140 includes an LCD and a touch panel, and can be operated by a user and information can be displayed. In this embodiment, the operation display unit 140 functions as both an operation unit and a display unit. The operation unit may be configured with a mouse, a tablet, or the like, and may be configured separately from a display unit such as an LCD.

  A paper feed tray 12 that stores and feeds paper is disposed on the lower side of the image forming apparatus main body 10. The paper feed tray 12 may be configured in multiple stages. In this embodiment, the paper corresponds to a transfer medium. The transfer medium is not limited to paper, and any material can be used as long as it can print and convey images. In addition to the sheet shape, the transfer medium may be a continuous medium.

In the image forming apparatus main body 10, a transport path 15 for transporting paper fed from the paper feed tray 12 is provided, and the image forming unit 16 is located in the middle of the transport path 15 in the image forming apparatus main body 10. Is provided.
A registration roller 19 that performs alignment and inclination adjustment is provided in the conveyance path 15 that reaches the image forming unit 16, and a sheet inclination detection sensor 20 is disposed immediately downstream of the registration roller 19. The sheet inclination detection sensor 20 has two passage sensors arranged in the width direction of the path along which the sheet is conveyed, and can detect the leading edge of the sheet with each sensor. The inclination of the paper can be detected based on the detected time difference.

  The image forming unit 16 includes a photoconductor 16A for each color, an intermediate transfer belt 16B, and a secondary transfer unit 16C. Around the photoconductor 16A, a charger, an LD, and a developer (not shown) are provided for each color. A vessel is placed. Further, a fixing device 16D is disposed in the conveyance path 15 on the downstream side of the secondary transfer portion 16C. In this embodiment, the conveyance path 15 constitutes a conveyance unit together with a conveyance roller, a drive motor, and the like not shown.

On the downstream side of the fixing device 16 </ b> D, the conveyance path 15 extends and is connected to the paper discharge unit 17. The paper discharge unit 17 may be provided with a paper discharge tray or the like as it is, or may be connected to a conveyance path of a post-processing apparatus (not shown). The post-processing apparatus may be included in the image forming apparatus or may not be included in the image forming apparatus.
Further, the conveyance path 15 has a reverse conveyance path 15A that branches on the downstream side of the fixing device 16D and joins the conveyance path 15 on the upstream side of the image forming unit 16. The reverse conveyance path 15A has a mechanism (not shown) for reversing the paper. The sheet reversed in the reverse conveyance path 15A can be returned to the conveyance path 15 upstream of the image forming unit 16 through the reverse conveyance path 15A to print an image on the back side of the paper.

In the image forming unit 16, the surface of the photoconductor 16A is uniformly charged before image writing by the charger, and the photoconductor 16A whose surface is uniformly charged by the image writing unit is irradiated with a laser or the like. An electrostatic latent image is formed on the surface. The developing device develops the electrostatic latent image formed on the photoreceptor 16A with a toner material. By this development processing, a toner image is formed on the photoreceptor 16A. The toner image on the photoconductor 16A is transferred to the intermediate transfer belt 16B, and the toner image is transferred to the paper conveyed from the paper feed tray 12 by the secondary transfer unit 16C. The sheet on which the toner image is transferred is conveyed along the conveyance path 15 and reaches the fixing device 16D.
The toner material remaining on the photoreceptor 16A and the intermediate transfer belt 16B is removed by a cleaning unit (not shown).

The fixing device 16D fixes the toner image transferred to the front side of the sheet as an output image by heating the conveyed sheet. This fixing completes the printing of the image on the paper.
The sheet on which the fixing process has been performed is directly discharged to the paper discharge unit 17 through the conveyance path 15, or the front and back are reversed through the reverse conveyance path 15A, and then returned to the conveyance path 15 on the upstream side of the image forming unit 16. The The sheet that has been turned upside down can be printed on the back side by the image forming unit 16.

  In the control unit of this embodiment, the additional image can be combined with the read image and printed. An additional image is usually attached to both print output and copy output. Types include page number, date, numbering (indicating the number of copies), special stamps (round secret, top secret, etc.), arbitrary stamps (Bates stamp * product name), copy protection, and the like. These are usually added on the assumption that the document does not include skew and bow. For this reason, if an image is synthesized while the read original is distorted and then corrected on the writing side, only the additional image is distorted in the opposite direction to reading.

FIG. 2 is an electrical block diagram of the image forming apparatus 1.
The overall control board 100 corresponds to a control unit of the present invention.
The overall control board 100 includes a CPU 101 and a system memory 102, and the system memory 102 is connected to the CPU 101 so as to be controllable. The system memory 102 is composed of a ROM, a nonvolatile memory, or the like. The ROM stores a program for causing the CPU 101 to execute a predetermined operation, and the nonvolatile memory stores a program for operating the CPU 101, setting data for the image forming apparatus, process control parameters, and the like. . Furthermore, the image data P1 of the additional image is stored in the nonvolatile memory.

Further, the overall control board 100 is provided with a local memory 103 constituted by a RAM or the like. The local memory 103 includes an image memory and the like, and can store an image memory such as a read image. Further, the additional image data may be stored in the local memory 103, and the additional image of the registered overlay can be stored in the local memory 103.
The system memory 102 and the local memory 103 constitute a storage unit of the present invention. In this embodiment, the storage unit is described as being included in the overall control board 100 which is a control unit, but the storage unit is distinguished from the control unit and is provided as a configuration different from the control unit. There may be.

The overall control board 100 has a memory control ASIC 105, and a system memory 102 and a local memory 103 are connected to be controllable. The memory control ASIC 105 can be controlled by the CPU 101.
Further, an image read by the scanner 130 is sent to the memory control ASIC 105. The read image is compressed by the memory control ASIC 105 and stored in the local memory 103 as read data G0.

Further, the reading inclination amount (original image inclination information) of the automatic document feeder (ADF) 13 and the scanner 130 is transmitted to the mechanical control board 14.
When the image is read by the scanner 130, the image inclination is determined mainly by the running of the scanner, the attachment of the lens system, and the way the chart is arranged. Adjustment is performed by reading a test chart and determining a correction value from the image data. Image distortion when an image is read by the automatic document feeder (ADF) 13 occurs due to attachment of the device and travel of the document. The inclination angle is detected by reading the leading edge of the document with two sensors and detecting the inclination angle based on this time difference.

The mechanical control board 14 is connected to loads such as charging, fixing, transfer, and other options to control various loads. In addition, a sheet inclination detection sensor 20 is connected to the mechanical control board 14, and a detection result is transmitted to the mechanical control board 14. The mechanical control board 14 is connected to the CPU 101 in a controllable manner. In the CPU 101, the detection result can be stored in the system memory 102 or the local memory 103.
Further, document image tilt information may be stored in the system memory 102 as a fixed value in advance. For example, the amount of deviation at the time of installation of the scanner or the conveyance device is fixed, and this can be measured in advance using a reference chart or the like.

  An image processing ASIC 104 is connected to the memory control ASIC 105 described above, and image data and read data G0 of the additional image P1 are sent through the memory control ASIC 105. In this embodiment, although not shown, the additional image P1 is temporarily stored in the local memory 103, and is rotated by the CPU 101 so as to have the same inclination as the read image according to the original image inclination information, and the memory control ASIC 105 is set. To the image processing ASIC 104.

  In the image writing control ASIC 108, the read data G0 can be expanded by the expansion module 1040. The synthesis module 1041 synthesizes the read data G1 decompressed by the decompression module 1040 and the additional image P1 subjected to the rotation process. After the composition, image quality adjustment unit 1042 performs image quality adjustment such as screen processing. For the image whose image has been adjusted, the image rotation unit 1043 performs rotation correction by combining the document image tilt information and the sheet tilt information. The rotated composite image is sent to the image writing control ASIC 108, writing data is generated, and sent to the laser writing control unit 160 to enable image formation.

FIG. 3 shows document image tilt detection sensors 13A and 13B in an automatic document feeder (ADF) 13. In FIG. The image tilt detection sensors 13A and 13B are installed with an interval in the width direction with respect to the conveyance direction of the document D. The image tilt detection sensors 13A and 13B detect the leading end position of the document D, respectively. FIG. 4 is a time chart showing detection results in the image inclination detection sensors 13A and 13B, and shows a time difference t between the sensors. Here, when the line speed of the document D is xt, the inclination angle θ2 can be calculated by the following formula, that is, the following formula 1.
θ2 = tan ⁻¹ (line speed xt / sensor distance) (1)

However, since the tilt angle detection based on this time difference cannot detect an absolute angle, the reference image is further read and adjusted. From the inclination angle θ1 from the image data when the reference image is read, the difference θ of the inclination angle θ2 detected by the sensor at that time is stored as a correction angle.
The actual reading correction angle is obtained by θ + θ2. (Θ corresponds to the inclination when the document feeder is installed)

On the other hand, when the paper is transported, the paper inclination detection sensor 20 can detect the inclination similarly. The inclination correction of the writing system is mainly required by running the transfer sheet at the time of paper feeding and attaching the writing / transfer.
FIG. 8A shows a case where the transfer paper P travels obliquely, and FIG. 8B shows a case where the transfer paper P travels straight but the transfer paper is inclined.
When forming an image in this state, if the image is not corrected, the finished image is printed in a rotated form with respect to the transfer paper.
Therefore, there is a technology that rotates and deforms an image with respect to a written image, and has a function of correcting actual running and attachment defects.
This function is a technology that outputs a reference image, measures image distortion such as rotation (skew), bow, and parallelogram on the transfer paper, and corrects it in the reverse direction.
However, if the same distortion correction is performed on the read image in a circuit different from writing, it is necessary to have a double correction circuit, and it is necessary to read and write the image processing twice. This is not preferable because of the possibility of deterioration. Therefore, the correction contents at the time of reading are stored, and correction is simultaneously performed at the time of writing.

FIG. 5 shows an outline of hardware configuration conditions.
The image memory stores read image data (for example, 8-bit data) and additional image data (for example, 8-bit data). The additional image is tilted based on the tilt detection result of the scanner. Since the read image is stored after being compressed, it is decompressed by the decompression module 1040. If it is multi-tone data, it is maintained. The rotated additional image data is added to the expanded read image, and the combined module 1041 combines it.
When the additional image to be synthesized has multiple gradations, an image taking the rotation angle into consideration is created on the memory and synthesized by the synthesis module. For this reason, images can be superimposed with multiple values, and image degradation is small. However, since the additional image is rotated with multiple values, resources such as a memory are necessary. However, since the additional image is usually small, there is no problem.

Image quality adjustment such as screen processing is performed on the synthesized image by the image quality adjustment module 1042. Rotation correction is performed on the image after image quality adjustment by adding the original image inclination angle and the paper inclination angle. Printing is executed with the rotation-corrected image.
When tilt correction is performed, correction with a multi-value image improves image quality but increases processing. If tilt correction is performed after binarization (after screen processing), image processing is simplified, but image quality degradation occurs. For this reason, in the writing inclination correction (function realized by the ASIC), the rotation is performed after the screen processing to lighten the processing and prevent image quality deterioration. It is desirable to rotate additional images such as numbering in a multivalued manner in consideration of image quality.

Next, the printing procedure will be described based on the flowchart of FIG. The following procedure is executed by control by the control unit.
With the start, it is determined whether there is an additional image (step s1). If there is no additional image (step s1, No), image rotation with respect to the additional image is not executed (step s8).
When there is an additional image (step s1, Yes), it is determined whether or not the document is obtained by scanning without using the document conveying device (step s2). If it is obtained by scanning, image rotation is performed on the additional images of all pages with the angle detection or fixed value of the first page (step s7).
If it is not a scanned image (No in step s2), it is determined that the image has been read using the document conveying device and the size of the additional image is equal to or smaller than a certain threshold A (step s3). The reference of A is set in advance and stored in the system memory 102 or the like.

  When the size of the additional image is equal to or smaller than the predetermined threshold A in step s3, rotation correction can be performed according to the rotation angle detected by the document conveying apparatus for each page. Even if the threshold value exceeds A, if the additional image is a single color binary, it is expected that the rotation processing time will be short, so that the rotation correction corresponding to the rotation angle detected by the document conveying apparatus for each page is performed. Can do. When it is predicted that the total rotation processing time is long, all the subsequent additional images are corrected at the same rotation angle at the rotation angle of the first page.

  Specifically, when the size of the additional image is A or less (step s3, A or less), after detecting the document image, the additional image for each page is rotated (step s4). If the size of the additional image is not less than or equal to A (step s3, over A), it is determined whether the additional image is a single color binary (step s5). If it is not a single color binary (No in step s5), if it is multi-gradation, it will not be in time if the additional image is rotated every page. To rotate the additional images of all pages (step s7). If the additional image is a single color binary (step s5, Yes), it is determined whether the total image rotation time is within a certain threshold B (step s6).

The reference for B is set in advance and stored in the system memory 102 or the like. When the total image rotation time is within B (step s6, Yes), after detecting the document image inclination, the additional image for each page is rotated (step s4). For example, when the image is a single color and has the maximum density, the image rotation time is shortened. In this case, since the image deterioration is small, the read image after the screen processing may be combined.
If it is not within B (step s6, No), the additional images of all pages are rotated by detecting the angle of the first page (step s7).
As described above, when the additional image has a large size, it is desirable to rotate the additional image based on the initially determined inclination angle. However, when the image size is different from page to page and the image size is larger than A, It is desirable to rotate the image based on the tilt angle initially determined before detecting the image tilt.
Since the additional image is rotated by software, when the same additional image is attached, image rotation of a certain size or more is not performed every page, only the first page is rotated, and the subsequent pages are images of the same rotation angle. use. For example, when adding images with different page contents such as page and Bates stamps, such as date and time, form overlay, etc., software in advance at the rotation angle of the first page (while reading the previous page) Prepare an image with.

Next, the contents of the control processing in the control unit will be described using the ladder diagram of FIG.
In the main task, processing is passed to the additional image processing task to create an additional image. For example, the additional image can be obtained by reading image data stored in the system memory and storing it in the image memory. The completion of creation is transmitted to the main task.
The main task then instructs the scanner task to read an image. In the scanner task, the DF task is instructed to read a document, and the tilt angle θ2 is notified to the additional image processing task and the main task. In the additional image processing task, the additional image is rotated by θ and the inclination angle θ2. In the image rotation of the additional image task, when the tilt angle of only the first page is used, the document reading apparatus can wait for the document reading until after the tilt is detected, or the document once read can be returned and read again.
In the scanner task, the image of the document is read and the read data is notified to the main task.

In the main task, a print instruction is instructed to the print image processing task, and the read image is expanded and the rotated additional image is synthesized. In the print instruction from the main, the inclination angle θ + θ2 detected by reading and information on where to synthesize the image are passed.
Next, screen processing is performed to obtain a writing rotation angle. The document image tilt information and the sheet tilt information are added together, and tilt correction is performed on the synthesized image to obtain image data for printing. Printing is executed based on the image data for printing.

  In the above-described embodiment, it has been described that image reading, image data processing, and printing are performed in the image forming apparatus. However, image reading and image data processing are performed, and a remote printer device is A print instruction may be given.

  As mentioned above, although this invention was demonstrated based on the said embodiment, an appropriate change is possible unless it deviates from the scope of the present invention.

1 Image forming device 13 Automatic document feeder (ADF)
DESCRIPTION OF SYMBOLS 15 Conveyance path 16 Image forming part 19 Registration roller 20 Paper inclination detection sensor 100 Overall control board 102 System memory 103 Local memory 130 Scanner 140 Operation display part

Claims (13)

A reading unit for reading a document image;
A control unit that performs image data processing,
The control unit obtains image tilt information of the read image, rotates the additional image so as to have the same tilt according to the image tilt information, and combines the rotated additional image with the read image to be combined. An image forming apparatus, wherein image data for printing is obtained by performing rotation correction on the obtained image based on the image tilt information. A document conveying device that conveys the document image and enables reading by the reading unit;
The document conveying device has an inclination detection unit that detects an inclination angle of the document being conveyed,
The image forming apparatus according to claim 1, wherein the control unit acquires the image tilt information based on a detection result of the tilt detection unit.   The image forming apparatus according to claim 1, wherein the control unit acquires inclination information of the read image for each sheet of the document.   4. The control unit according to claim 1, wherein the control unit shares the tilt information of the read image with all the pages of the document using information acquired for the first sheet of the document. 5. Image forming apparatus. Image tilt information of the read image is stored as a fixed value in the storage unit,
5. The image forming apparatus according to claim 1, wherein the control unit acquires image tilt information based on a fixed value stored in the storage unit.   The said control part acquires the sheet | seat inclination information of the sheet | seat conveyed in preparation for printing, adds a sheet | seat inclination information to the said image inclination information, and performs the said rotation correction, Any one of Claims 1-5 characterized by the above-mentioned. The image forming apparatus according to claim 1.   The control unit has a function of adjusting the image quality of the image data, and before the image quality adjustment is performed on the read image, the rotated additional image is synthesized and the image quality adjustment is performed on the synthesized image. The image forming apparatus according to claim 1, wherein the rotation correction is performed thereafter.   The said control part synthesize | combines the rotated said additional image with the image after the image quality adjustment with respect to the read image, when the said additional image is a single color and the maximum density, Then, rotation correction is performed, It is characterized by the above-mentioned. The image forming apparatus according to any one of 1 to 7.   The image forming apparatus according to claim 1, wherein the control unit performs an expansion process on the image data of the read image before the image quality adjustment.   The image forming apparatus according to claim 9, wherein when the additional image rotated before the image quality adjustment is combined, the image is combined after the decompression process.   When the additional image is the same image for each page and the image size is equal to or larger than a predetermined value, the additional image is rotated and combined with the original image based on inclination information determined first. The image forming apparatus according to claim 1.   When the additional image varies from page to page and the image size is equal to or larger than a predetermined value, the additional image is rotated before the image tilt information is acquired based on the tilt information determined first. The image forming apparatus according to claim 1, wherein the image forming apparatus combines the images. In an image forming method for performing printing based on image data,
A reading process for reading a document image;
A data processing step for performing data processing of the image data,
In the data processing step, control is performed to acquire image tilt information of the original image, rotate the additional image so as to have the same tilt based on the image tilt information, and combine the rotated additional image with the read image. Further, the image forming method is characterized in that control is performed to obtain image data for printing by rotationally correcting an image synthesized based on the image tilt information.

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