JP3902364B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly to a technique for correcting an image in the vicinity of a binding portion in copying a double-sided spread book document.
[0002]
[Prior art]
When copying a left and right facing book document, the binding portion is lifted. The degree of lifting increases as the thickness of the book document increases.
[0003]
[Problems to be solved by the invention]
As described above, in the case of a two-page spread book document, the binding portion at the center rises, so if there are characters and figures in the document near the binding portion, the characters and drawings in the vicinity of the binding portion are copied. There is a problem that the image is distorted and difficult to see.
[0004]
In addition, since the center binding portion becomes black and is copied, so-called center erasure (erasing black (background)) is performed. However, this may cause loss of characters and drawings of the original document near the binding portion. there were. Incidentally, as a technology related to left and right facing book original copying, JP-A-9-247422 and others can be cited.
[0005]
The present invention can prevent loss of image data such as characters and figures in the vicinity of the binding portion of the left and right spread book document, and can suppress distortion of image data such as characters and figures in the vicinity of the binding portion. An object is to provide a forming apparatus.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an image forming apparatus of the present invention is detected by a storage unit that stores image data of an original, an image density detection unit that detects an image density in the main scanning direction, and an image density detection unit. A boundary detection unit for detecting a boundary in the main scanning direction between a document area and a non-document area in the image, a document width detection unit for detecting a document width using the boundary detection unit, and a document width The position detection means for detecting the position of the binding portion of the left and right spread book document by obtaining the minimum value of the document width from the document width detected by the detection means, and the document width data in the image obtained by the document width detection means And a mode value determining means for determining the mode value of the document width, and a distortion for correcting image distortion in the vicinity of the binding portion using the mode value of the document width obtained from the mode value determining means. It is assumed that a correction means.
[0007]
Further , as a first application, the difference between the position of the left and right facing book original binding portion detected by the position detecting means and the center position of the transfer paper is obtained, and the image data is obtained from the center of the transfer paper and the left and right facing book original. It is also possible to include a matching means for matching the binding portion and the center of the transfer paper by translating in the sub-scanning direction by the difference from the position of the binding portion.
[0008]
As a second application , the image data is divided with the left and right facing book original binding portion as the boundary, the image data on the left side of the boundary is on one side of the first transfer paper, and the image data on the right side of the boundary is two sheets. It is good also as what was equipped with the printing means which prints on each side of the transfer paper of eyes.
[0009]
In particular, according to the present invention, the image data is divided on the boundary of the binding portion of the right- and- left spread book document based on the position of the binding portion detected by the position detecting unit, and the image data on the left side of the boundary is transferred to the surface of the transfer sheet. In addition, printing means for printing image data on the right side of the boundary on the back side of the same transfer paper is provided.
[0010]
According to the present invention, loss of image data such as characters and figures in the vicinity of the binding portion of the left and right spread book document is prevented, and distortion of image data such as characters and figures in the vicinity of the binding portion is suppressed.
[0011]
According to the first application, in addition to the above, the difference between the detected position of the binding portion and the center of the transfer paper in the sub-scanning direction is obtained, and image data is subtracted in the sub-scanning direction by this difference. Therefore, the operation of matching the position of the binding portion and the center of the transfer sheet in the sub-scanning direction can be automated, and the operation of matching this position is omitted.
[0012]
Further, according to the second application, when printing a left and right facing book document on one side of two transfer papers, in addition to the operation of the present invention, the center of the image data of each page and the center of the transfer paper in the sub-scanning direction. Since the image data is moved in the sub-scanning direction by this difference, it is possible to automate the operation of matching the position of the center of the image data of each page with the center of the transfer paper in the sub-scanning direction. The work of matching the positions is omitted.
[0013]
In particular, according to the present invention, the above-described operation can be obtained when printing a left and right spread book original on both sides of a single transfer sheet.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a control block diagram of an image forming apparatus according to the present invention.
A CPU 103 is located at the center of the control block, and commands each device. The ROM 101 stores a control program executed by the CPU 103. The RAM 102 temporarily stores various parameters and image data. The CPU 103 constitutes each functional means according to claims 1 to 4. The image reading unit 105, the operation unit 106, the image forming unit 107, and the image processing unit 108 are connected to the CPU 103 via each driver 104.
[0015]
Next, a series of operations in the copying process will be described in order. First, in the operation unit 106, the number of copies, a copy method such as book copy, various modes, and the like are input using keys.
[0016]
Next, the image reading unit 105 reads the document on the document table based on the information input by the operation unit 106. The read image data of the document is temporarily stored in the RAM 102. The image data stored in the RAM 102 is converted based on information input from the operation unit 106 by the image processing unit 108. Thereafter, the image data stored in the RAM 102 is output from the image forming unit 107.
[0017]
FIG. 2 shows the copy state of the book document.
When a book document is placed on the document table and pressed by the pressure plate, light enters from the side surface, so that the image density in the non-document area 201 is output higher than that in the document area 202. In addition, when copying a book document, the document width 204 is the smallest at the binding portion 203 that is a joint between the left page and the right page of the book document.
[0018]
FIG. 3 shows the characteristics of the image density on the line segment AB in FIG.
Reference numeral 301 in FIG. 3 denotes a curve relating to the characteristics of the image density. According to FIG. 3, the curve changes remarkably in the vicinity of the points 302A and 302B that are the boundaries between the non-image area and the image density characteristics in the non-image area exceed a certain threshold value. Yes.
[0019]
FIG. 4 is a flowchart relating to the detection processing of the binding portion position of the book document.
Reference numerals 401 to 405 denote processing steps (the same applies to the following flowcharts).
In 401, the process of FIG. 4 is started. In 402, the boundary between the image area and the non-image area is detected.
[0020]
The detection method uses the feature in the image density characteristic of FIG. A point where the image density characteristic decreases from above a preset threshold value while proceeding in the main scanning direction at an arbitrary point in the sub-scanning direction is defined as a boundary A, and the image density characteristic is reduced. A point increasing from the bottom to the top of the threshold is detected as a boundary B.
[0021]
After detecting the boundary between the image area and the non-image area, the document width is detected at 403. The difference between the boundary A and the boundary B detected in the above-described 402 is the document width. In 403, data on the document width at each position in the sub-scanning direction is stored.
[0022]
After detecting the document width, in 404, the position of the binding portion is detected. According to FIG. 2, when copying a book document, since the document width is minimized at the position of the binding portion, the position in the sub-scanning direction where the document width is minimized is specified. Thereafter, the process returns to the main program of FIG.
[0023]
FIG. 5 is a conceptual diagram relating to a distortion correction process in the vicinity of the binding portion.
Reference numeral 501 denotes a non-original area, 502 denotes an original area, and 503 denotes a binding portion. Since the portion of the original width reduced by the binding portion 503 is a little relative to the coordinates in the entire sub-scanning direction, the actual original width of the left and right facing book original is the middle of the original width obtained at 403 in FIG. Mode value (hereinafter referred to as the document width mode value) 504.
[0024]
In the vicinity of the binding portion 503, the document width is shorter than the mode value 504 of the document width. A portion where the document width is shorter than the mode value 504 of the document width is handled as an area 505 for correcting an image.
[0025]
FIG. 6 shows a flowchart relating to the distortion correction process in the vicinity of the binding portion.
In 601, the process of FIG. 6 is started. At 602, the mode value 504 of the document width is determined from the document width obtained at 403 in FIG. In 603, an arbitrary point x in the sub-scanning direction is set at the left end of the image data.
[0026]
In 604, if the document width value at the point x is smaller than the mode value 504 of the document width, the process moves to 605, and if not, the process moves to 607. In 605, the image data at the point x is read. In 606, the image data at the point x is corrected so that the document width at the point x becomes the mode value 504 of the document width. A detailed method of correcting the image data will be described later with reference to FIG.
[0027]
If the variable x in the sub-scanning direction reaches the right edge of the image in 607, the process moves to 609, and if not, the process moves to 608. In 608, the variable x is incremented by 1 to shift the processing to the next image data. At 609, the process of FIG. 6 ends, and the process returns to the program point before the process of FIG. 6 is called.
[0028]
FIG. 7 shows a conceptual diagram of a method for correcting image data in the vicinity of the binding portion.
In FIG. 7, 702y represents the coordinates in the main scanning direction in the image data before correction, and 705Y represents the coordinates in the main scanning direction in the image data after correction. The image data at the boundary 701A between the image area and the non-image area is moved to the boundary 704Amed above the image area and the non-image area at the mode of the document width by the correction, and the boundary below the image area and the non-image area. The image data of 703B is moved to the lower boundary 706Bmed of the image area and the non-image area in the mode value of the document width by correction, and the upper and lower boundaries of the image data of the boundaries 701A and 703B are as described above. Since the image is enlarged so as to move to, the conversion from the coordinate y before correction to the coordinate Y after correction is linear.
[0029]
The conversion from the coordinate y before correction to the coordinate Y after correction is expressed as follows.
Y = (Amed−Bmed) · y / (A−B) + (Bmed · A−Amed · B) / (A−B)
Based on this equation, the image data at a certain point y in the main scanning direction is moved to the point Y from the top to the bottom of the image data.
[0030]
Since the correction of the image data is enlargement, the coordinates of adjacent yi and y (i + 1) before correction are often not adjacent to the coordinates of corrected coordinates Yi and Y (i + 1). That is, image data between Yi and Y (i + 1) is lost. When the coordinates of the image data are missing, the image data is interpolated by filling the Yi image data between Yi and Y (i + 1). As described above, the image data in the vicinity of the binding portion is corrected.
[0031]
FIG. 8 is a conceptual diagram relating to processing for matching the binding portion and the center of the transfer sheet.
In FIG. 8, reference numeral 801 is a book original image, 802 is transfer paper, 803 is a binding portion, 804 is a first page book original image, 805 is a second page book original image, and 806 is transfer paper 802. The center of is shown. In order to make the copy easy to see, it is necessary to match the position of the binding portion 803 with the center 806 of the transfer paper 802.
[0032]
FIG. 9 is a flowchart relating to a process for matching the binding portion and the center of the transfer sheet.
In 901, the processing of FIG. 9 is started. In 902, the difference between the position of the binding portion obtained in FIG. 4 and the center of the transfer paper in the sub-scanning direction is obtained. 1, the image processing unit 108 in FIG. 1 shifts the image data in the RAM 102 in FIG. 1 in the sub-scanning direction by the difference between the position of the binding portion obtained in 902 and the center of the transfer paper in the sub-scanning direction. Move. Thereafter, at 904, the process returns to the main program.
[0033]
FIG. 10 is a conceptual diagram of a process for moving the image of the left-right spread book document to an appropriate position on two single-sided transfer sheets.
Reference numerals 1001 and 1002 are images of the first and second pages of the book document, 1003 and 1004 are transfer sheets on which each image is transferred, 1005 and 1006 are binding portions, and 1007 and 1008 are the centers of the transfer sheets 1003 and 1004 , 1009 indicates the left end, and 1010 indicates the right end.
[0034]
In order to make the copy easier to see, the image of the left and right facing book document is divided into two pages with the binding portions 1005 and 1006 as the boundary, and the center of each page is the center 1007 and 1008 of the respective transfer sheets 1003 and 1004. Need to match.
[0035]
FIG. 11 shows a flowchart of a process for moving the image of a left-right spread book document to an appropriate position on two single-sided transfer sheets.
First, in 1101, the process of FIG. 11 is started. Next, in 1102, the image data of the left and right spread book document is divided with the position of the binding portion detected in FIG. 4 as the boundary, the left from the boundary as the first page, and the right from the boundary as the second page.
[0036]
Then, in order to make the image data of the first page coincide with the center of the transfer paper, in 1103, the difference between the middle position of the left end of the image data and the binding portion and the center of the transfer paper of the first page is obtained. The image data of the first page is moved in the sub-scanning direction by the difference between the middle of the position of the left end of the image data and the binding portion and the center of the transfer paper of the first page.
[0037]
Similarly, in order to make the image data of the second page coincide with the center of the transfer paper, in 1105, the difference between the right end of the image data and the position of the binding portion and the center of the transfer paper of the second page is obtained. The image data of the second page is moved in the sub-scanning direction by the difference between the right end of the image data and the middle position of the binding portion and the center of the transfer paper of the second page. Thereafter, in 1107, the process returns to the main program.
[0038]
FIG. 12 shows a conceptual diagram of a process for moving the image of the left and right facing book document to an appropriate position on one side of the transfer paper.
Reference numerals 1201 and 1202 are images of the first and second pages of the book document, 1203 is a transfer paper on which each image is transferred on the front and back, 1204 and 1205 are binding portions, 1206 is the center of the transfer paper 1203, and 1207 is The left end 1208 indicates the right end.
[0039]
In order to make the copy easy to see, first, it is necessary to divide the image of the left and right facing book original into two pages with the binding portions 1204 and 1205 as a boundary, and to further make the center of each page coincide with the center 1206 of the transfer paper 1203. is there.
[0040]
FIG. 13 shows a flowchart of a process for moving the image of the left and right facing book document to an appropriate position on both sides of the transfer sheet.
First, in 1301, the process of FIG. 13 is started. Next, in 1302, the image data of the left and right spread book document is divided with the position of the binding portion detected in FIG. 4 as the boundary, the left from the boundary as the first page, and the right from the boundary as the second page.
[0041]
Then, in order to match the image data of the first page and the center of the transfer sheet, in 1303, the difference between the left end of the image data and the position of the binding portion and the center of the transfer sheet on the first page, that is, the front side of the transfer sheet is determined. In step 1304, the image data of the first page is translated in the sub-scanning direction by the difference between the middle of the position of the left end of the image data and the binding portion and the center of the transfer sheet of the first page.
[0042]
Similarly, in order to make the image data of the second page coincide with the center of the transfer paper, in 1305, the difference between the right edge of the image data and the position of the binding portion and the center of the second page, that is, the transfer paper on the back side is determined. In step 1306, the image data of the second page is translated in the sub-scan direction by the difference between the middle of the position of the left end of the image data and the binding portion and the center of the transfer paper of the second page. Thereafter, in 1307, the process returns to the main program.
[0043]
FIG. 14 shows a flowchart of the main program.
In 1401, processing of the main program is started. In 1402, information input from the operation unit 106 such as the number of printed sheets and a finishing method such as stapling is read. In 1403, the image of the document on the document table is read, and the image information is temporarily stored in the RAM 102.
[0044]
In 1404, it is determined whether or not the document is a book document from the input information from the operation unit 106. If it is a book document, the process jumps to 1407, and if not, the process jumps to 1405. In 1405, image processing according to the input from the operation unit 106 is performed on the image of the document in the RAM 102. In 1407, the process jumps to the binding portion position detection process in FIG. 4 to detect the position of the binding portion in the main scanning direction.
[0045]
In step 1409, the process jumps to the process of matching the binding portion of FIG. 9 with the center of the transfer sheet, and the process of matching the binding position of the book document with the center of the transfer sheet is performed. Then, in 1409, the process jumps to a process for correcting the distortion in the vicinity of the binding portion, and the correction process is performed.
[0046]
In 1408, the processing destination is changed according to the printing method obtained from the input information of the operation unit 106. If the left and right facing book document is printed on one side, the process jumps to 1406, if it is printed on two sides, 1410, and if it is printed on both sides, 1411.
[0047]
Then, in 1410, the process jumps to the process of moving the image transfer paper on one side of the two-page spread book original in FIG. 11 to an appropriate position, and the process of matching the image of each page of the book original with the center of one side of the two transfer papers. After that, go to 1406.
[0048]
In step 1411, the process jumps to a process of moving the left and right facing book original of FIG. 10 to an appropriate position on both sides of one transfer paper, and a process for matching the image of each page of the book original with the center of both sides of one transfer paper. Then, the process proceeds to 1406. In 1406, the image forming unit forms an image of the original in the RAM 102 on the photosensitive member, and transfers the image onto a transfer sheet. Finally, at 1412, the main program is terminated.
[0049]
【The invention's effect】
According to the present invention, it is possible to prevent loss of image data such as characters and figures in the vicinity of the binding portion of the left and right spread book document, and to suppress distortion of image data such as characters and figures in the vicinity of the binding portion. it can.
[0050]
According to the first application, in addition to the above, the difference between the detected position of the binding portion and the center of the transfer paper in the sub-scanning direction is obtained, and the image data is moved in the sub-scanning direction by this difference. Thus, it is possible to automate the operation of matching the position of the binding portion and the center of the transfer paper in the sub-scanning direction, and the operation of matching this position can be omitted.
[0051]
According to the second application, when printing a left and right facing book document on one side of two transfer papers, in addition to the operation of the present invention, the center of the image data of each page and the center of the transfer paper in the sub-scanning direction are used. Since the difference is obtained and the image data is moved by this difference in the sub-scanning direction, it is possible to automate the operation of matching the center of the image data of each page with the center of the transfer paper in the sub-scanning direction. It is possible to omit the work of matching the.
[0052]
In particular, according to the present invention, the above-described effect can be obtained when printing a left and right spread book original on both sides of a single transfer sheet.
[Brief description of the drawings]
FIG. 1 is a control block diagram of an image forming apparatus according to the present invention.
FIG. 2 is a diagram illustrating a copy state of a book document.
FIG. 3 is a diagram illustrating image density characteristics on a line segment AB in FIG. 2;
FIG. 4 is a flowchart related to a detection process of a binding portion position of a book document.
FIG. 5 is a conceptual diagram relating to a distortion correction process in the vicinity of a binding portion.
FIG. 6 is a flowchart regarding distortion correction processing in the vicinity of a binding portion.
FIG. 7 is a conceptual diagram of a method for correcting image data in the vicinity of a binding portion.
FIG. 8 is a conceptual diagram related to processing for matching a binding portion and a transfer sheet center.
FIG. 9 is a flowchart relating to a process for matching a binding portion and a transfer sheet center.
FIG. 10 is a conceptual diagram of processing for moving an image of a left and right facing book document to an appropriate position on two sheets of one side of a transfer sheet.
FIG. 11 is a flowchart of a process of moving an image of a left-right spread book original to an appropriate position on two transfer paper single sides.
FIG. 12 is a conceptual diagram of a process for moving an image of a left and right facing book document to an appropriate position on one side of a transfer sheet.
FIG. 13 is a flowchart of a process for moving an image of a left-right spread book document to an appropriate position on one side of a transfer sheet.
FIG. 14 is a flowchart of the main program.
[Explanation of symbols]
101 ROM
102 RAM
103 CPU
104 Driver 105 Image Reading Unit 106 Operation Unit 107 Image Forming Unit 108 Image Processing Unit

Claims (1)

Storage means for storing image data of a document;
Image density detecting means for detecting the density of the image in the main scanning direction;
Boundary detection means for detecting the boundary in the main scanning direction between the document area and the non-document area in the image using the density data of the image detected by the image density detection means;
Document width detection means for detecting the document width using the boundary detection means;
Position detecting means for detecting the position of the binding portion of the left and right facing book document by obtaining the minimum value of the document width from the document width detected by the document width detecting means;
Mode value determining means for determining the mode value of the document width using the document width data in the image obtained from the document width detecting means;
Using the mode of the original width obtained from the most frequent value determining means, a distortion correction means for correcting the distortion of the image in the stitching around portion,
Based on the position of the binding portion detected by the position detection means , the image data is divided with the binding portion of the left and right spread book document as a boundary, and the image data on the left side of the boundary is displayed on the front side of the transfer paper, and on the right side of the boundary An image forming apparatus comprising: printing means for printing the image data on the back of the same transfer paper.

Images