JP5021524B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that can form an image by adjusting the background density of an image to be formed based on the background density of a read original.

  Some image forming apparatuses are provided with an image reading apparatus capable of reading a document placed on a placing table. The image forming apparatus detects the density and size of the original from the original read by the image reading apparatus, and forms an image.

  When an image is formed, the background density of the entire image to be formed is adjusted based on the background density of a part of the read original. For example, when an image is formed from a newspaper or the like, since the background color of the newspaper is gray, the background density is adjusted so that the gray color is white, that is, the dark color is light.

  Here, when a page such as a book is opened and the opened page is used as a document (hereinafter referred to as “spread document”), when the spread document is placed on the mounting table, the page is positioned at the center of the spread document. The binding part may float from the mounting table. As a result, when the spread document is read, a shadow is generated on the mounting table side of the binding unit, so that the image forming apparatus detects the background density around the binding unit to be darker than the actual background density of the spread document.

  In such a case, a technique for forming an image by correcting the background density around the binding portion is disclosed in Japanese Patent Laid-Open No. 11-341230 (Patent Document 1). According to Patent Document 1, the background density is corrected according to the binding portion depth of the read spread original, and an image is formed with the background density corrected around the binding portion.

Japanese Laid-Open Patent Publication No. 3-178264 (Patent Document 2) discloses a technique for detecting the density of an original for each page and forming an image with different densities when a spread original is read. . According to Patent Document 2, the image forming apparatus detects the density of the first page and the density of the second page. Then, an image of the first page is formed according to the density of the first page, and an image of the second page is formed according to the density of the second page.
Japanese Patent Laid-Open No. 11-341230 (FIG. 10) Japanese Patent Laid-Open No. 3-178264

  FIG. 9 is a view of the placement table 102 on which the spread original 103 is placed as seen from the lateral direction. Referring to FIG. 9, an optical unit 105 that reads the background density of the spread spread original 103 is provided below the placement table 102. Further, the spread original 103 is placed at a position slightly deviated in the sub-scanning direction indicated by an arrow D in FIG. 9 from the reference position indicated by a dotted line in FIG. In such a case, the vicinity of the binding portion 104 of the spread original 103 may be a partial area 106 for detecting the background density on the second page 107 of the spread original 103. In this case, a shadow is generated on the mounting table 102 side of the binding unit 104, so that although the background density is actually white, it is detected darkly as gray. Then, in the image forming method of Patent Document 2, since the background density of the second page 107 is adjusted based on this, the density of the image of the second page 107 to be formed may be reduced.

  Further, in the image forming method of Patent Document 1, when the background density around the binding portion is corrected, correction is performed using a large number of calculation methods. As a result, the image forming process is complicated and time-consuming, and it may be difficult to form an image easily.

  An object of the present invention is to provide an image forming apparatus that can easily form a good image even for a spread original.

  The image forming apparatus according to the present invention adjusts the background density of the image to be formed based on the background density of the read document. A placing means for placing a spread document having a face of a book opened as a document, and a spread document placed on the placement means, at an end of the spread document, Detecting means for detecting the background density of the first area located on the first page and the second area located at the center of the spread original and located on the second page on the other side; the first area detected by the detecting means; A discriminating unit that discriminates whether or not the density difference between the background density of the first region and the background density of the second region is equal to or greater than a predetermined value; and an adjusting unit that adjusts the background density of the image to be formed. A detecting unit that detects a background density of a predetermined region that is located on the second page and includes a region different from the second region when the determining unit determines that the density difference is equal to or greater than the predetermined value; Adjusts the background density of the image to be formed based on the background density of the predetermined area detected by the detection means.

  Preferably, the detection means moves in the direction from the first page to the second page in the region, detects the background density, and selects the lightest density.

  As one embodiment, the predetermined area is an area located in the direction in which the detection means moves from the second area.

  More preferably, an area setting means for setting a predetermined area is provided.

  According to the present invention, the background density of the first region located on the first page, which is the edge of the spread document, and the background of the second region, located on the second page, in the center of the spread document. If the density difference from the density is equal to or greater than a predetermined value, the background density of a predetermined area located on the second page and including an area different from the second area is detected. Then, the background density of the image to be formed is adjusted based on the detected background density of the predetermined area. Thereby, the possibility of forming an image with a low density can be reduced, and a good image can be formed. Further, since it is only necessary to detect the background density of a predetermined area, the image forming process is complicated and does not take time. Therefore, a good image can be easily formed even with a spread document.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a digital multifunction peripheral 10 when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral 10. Referring to FIG. 1, a digital multifunction peripheral 10 displays a control unit 11 that controls the entire digital multifunction peripheral 10, a DRAM 12 for writing and reading image data and the like, and information that the digital multifunction peripheral 10 has. An operation unit 13 that includes a display screen and serves as an interface with the user in the digital multi-function peripheral 10, a document feeder 14 that automatically transports a document to a predetermined document reading position, and a document that has been transported by the document feeder 14 The image is read from the image reading unit 15 by a scanner at a predetermined reading position, the image reading device 23 for reading the document placed on the mounting table, and the document read by the image reading unit 15 and the image reading device 23 to form an image. Then, the image forming unit 16 that outputs to paper, the hard disk 17 that stores image data and the like, and the FAX connected to the public line 20 Comprises a signal unit 18, a network IF (interface) unit 19 for connecting to a network 21.

  The digital multifunction machine 10 operates as a copying machine by forming an image in the image forming unit 16 via the DRAM 12 using image data of the original read by the image reading unit 15 and the image reading device 23. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 via the DRAM 12 using the image data transmitted from the personal computer 22 connected to the network 21 through the network IF unit 19, thereby serving as a printer. Operate. Further, the digital multi-function peripheral 10 forms an image in the image forming unit 16 via the DRAM 12 using the image data transmitted from the public line 20 through the FAX communication unit 18, and the image reading unit 15 and By transmitting the image data of the original read by the image reading device 23 to the public line 20 through the FAX communication unit 18, the facsimile device operates. That is, the digital multi-function peripheral 10 has a plurality of functions such as a copying (copying) function, a printer function, and a FAX function regarding image processing. Further, each function has functions that can be set in more detail.

  In FIG. 1, thick arrows indicate the flow of image data, and thin arrows indicate the flow of control signals or control data.

  The control unit 11 compresses and writes the image data of the original document supplied from the image reading unit 15 to the DRAM 12, reads the data written to the DRAM 12, decompresses and decodes the data, and outputs it by the image forming unit 16.

  Here, the image reading device 23 will be specifically described. FIG. 2 is a schematic view of the image reading device 23 provided in the digital multifunction peripheral 10 as viewed from above. FIG. 3 is a schematic view of the image reading device 23 shown in FIG. 1 to 3, the image reading device 23 reads a placement table 24 as a placement unit for placing a document, a document placed on the placement table 24, and the density and size of the document. And an optical unit 30 for detecting.

  The mounting table 24 is made of a transparent platen glass, and a document can be placed thereon. Here, a two-page spread 25 is placed as a document with the side of the book opened as a document. 2 and 3, the spread original 25 is placed at the reference position. The facing document 25 is composed of a first page 31 and a second page 32. The first page 31 is located on one side of the spread original 25, that is, the left side of FIGS. 2 and 3, and the second page 32 is located on the other side of the spread original 25, that is, the right side of FIGS. To do. A binding portion 29 is provided between the first page 31 and the second page 32. The binding portion 29 of the spread original 25 is placed in a state of being lifted from the placement table 24, and a shadow is generated on the placement table 24 side of the binding portion 29.

  The optical unit 30 is provided below the mounting table 24. The optical unit 30 includes a light source 28 indicated by a three-dot chain line in FIG. 2, a plurality of mirrors (not shown), a lens, and a CCD (Charge Coupled Device) image sensor. The light source 28 can move in the sub-scanning direction, that is, the direction of arrow B in FIG.

  Here, a method of reading an original with the optical unit 30 will be briefly described. First, the mounting table 24 is irradiated with light while moving the light source 28 in the sub-scanning direction. The irradiated light hits the document and is reflected. The reflected light is collected by a plurality of mirrors and lenses. By reading this condensed light with a CCD image sensor, image data of the original is read.

  The control unit 11 operates as detection means for detecting the background density of the spread original 25 from the image data of the spread original 25 read by the optical unit 30. Specifically, the background density is detected from the image data of the spread original 25 read in the first area 26 indicated by the alternate long and short dash line in FIG. 2 and the second area 27 indicated by the thick line in FIG.

  The first region 26 is located at the left end portion of the first page 31. That is, the first area 26 is located at the end of the spread document 25 as a whole. The second region 27 is located at the left end portion of the second page 32. That is, the second area 27 is located in the center of the spread original 25 as a whole.

  The control unit 11 detects the background density in one reading operation of the spread original 25. Specifically, the control unit 11 detects the background density by moving in the direction from the first page 31 to the second page 32, that is, in the sub-scanning direction. Therefore, first, the background density in the first area 26 is detected, and then the background density in the second area 27 is detected.

  FIG. 4 is an enlarged view in which the first region 26 indicated by the alternate long and short dash line in FIG. 2 is enlarged. The case where the background density is detected in the first region 26 will be described with reference to FIGS.

  First, the density with the highest distribution is extracted from one line 33 in the main scanning direction indicated by an arrow C in FIG. Although not shown, there are a plurality of lines, and each line is similarly extracted in the sub-scanning direction. Then, the lowest density among the plurality of lines is selected. The selected light density is set as the background density of the first region 26. In this way, the background density in the first region 26 is detected. Then, the detected background density is set as the background density of the first page 31 of the document 25.

  Similarly, in the second region 27 indicated by a thick line in FIG. 2, the density with the highest distribution is extracted from one line, and the lightest density is selected from among a plurality of lines. The selected light density is set as the background density of the second region 27. In this way, the background density in the second region 27 is detected. Then, the detected background density is set as the background density of the second page 32 of the document 25.

  In addition, the control unit 11 operates as a determination unit that determines whether or not the density difference between the background density of the first area 26 and the background density of the second area 27 is equal to or greater than a predetermined value. Specifically, it will be described later.

  Next, a case where an image is formed using the copy function of the digital multi-function peripheral 10 will be described. In the description, for example, it is assumed that the density is expressed by 256 gradations, the white density value is 20, the gray density value is 128, and the black density value is 255. The predetermined value of the difference in density between the background density of the first area 26 and the background density of the second area 27 is set to 100. FIG. 5 is a flowchart illustrating a case where an image is formed using the copy function of the digital multifunction peripheral 10. FIG. 6 is a diagram illustrating an example in which the facing original 40 is placed at a position slightly shifted from the reference position in the sub-scanning direction.

  Referring to FIGS. 5 and 6, first, the spread original 40 is placed on the placement table 24 (in FIG. 5, step S <b> 11, the following steps are omitted). Here, the facing document 40 is placed at a position slightly shifted in the sub-scanning direction from the reference position indicated by the dotted line in FIG. 6, and the binding portion 41 of the facing document 40 is applied to the second region 27. The control unit 11 receives a request for image formation of the spread original 40 (S12).

  Then, the image reading device 23 first starts reading the first page 42 of the spread original 40 (S13). Then, when reading of the image data located in the first area 26 is completed on the first page 42, the background density of the first area 26 is detected (S14). In this case, since the first page 42 is appropriately placed on the placement table 24, the detected background density value is set to 20 as white.

  Next, the image reading device 23 starts reading the second page 43 of the spread original 40 (S15). Then, when the reading of the image data located in the second area 27 is finished on the second page 43, the background density of the second area 27 is detected (S16). In this case, the binding area 41 is applied to the second region 27, and a shadow is generated on the mounting table 24 side of the binding area 41. Therefore, the density value of the detected background density is assumed to be 128 in gray.

  The control unit 11 determines a density difference between the background density density value of the first area 26 and the background density density value of the second area 27. Here, since the density value of the background density of the first region 26 is 20 and the density value of the background density of the second region 27 is 128, it is determined that the density difference is 108. Here, the control unit 11 operates as a determination unit. Then, the determined 108 is compared with a predetermined value of 100, and the density difference is 100 or more (YES in S17).

  Then, the control unit 11 detects the background density of the predetermined area 44 (S18). The predetermined area 44 is located on the second page 43 and includes a different area from the second area 27. In this embodiment, as shown by a thick line in FIG. 7, the second region 27 is included and a region extending in the sub-scanning direction is included. FIG. 7 is a diagram showing the predetermined area 44. Since the configuration other than the predetermined area 44 is the same as that in FIG. 6, the same reference numerals are assigned and description thereof is omitted. Thereby, since the predetermined area 44 includes a part away from the binding portion 41, even when a shadow is generated on the mounting table 24 side, the influence can be reduced and the background density can be detected. it can. Therefore, the density value of the detected background density is a value close to 20 of the white color described above.

  Then, the background density of the image to be formed is adjusted (S19). Specifically, on the first page 42, the background density of the image to be formed is adjusted based on the background density of the first area 26, and on the second page 43, based on the background density of the predetermined area 44. To do. Here, the control unit 11 operates as an adjustment unit. The image forming unit 16 forms an image with the adjusted background density (S20).

  By doing so, the background density of the first region 26 located on the first page 42 at the end of the spread document 40 and the second portion 43 located on the second page 43 at the center of the spread document 40. If the density difference between the second area 27 and the background density is a predetermined value or more, the background density of the predetermined area 44 located on the second page 43 and including an area different from the second area 27 is detected. Then, based on the detected background density of the predetermined region 44, the background density of the image to be formed is adjusted. Thereby, the possibility of forming an image with a low density can be reduced, and a good image can be formed. Further, since it is only necessary to detect the background density of the predetermined region 44, the image forming process is complicated and does not take time. Therefore, a good image can be easily formed even with the spread original 40.

  In step 17 in FIG. 5, if the spread original 40 is placed without being deviated from the reference position, and the density difference is smaller than 100 (NO in S17), the first page 42 is On the second page 43, based on the background density of the first area 26, the background density of the image to be formed is adjusted based on the background density of the second area 27 (S19).

  In the above embodiment, the example in which the predetermined area 44 includes the second area 27 and includes an area extending in the sub-scanning direction has been described in step 18 in FIG. The region is not limited to the second region 27 and may be a region positioned in the sub-scanning direction. FIG. 8 is a diagram illustrating an example in which the predetermined area 45 is provided so as to be positioned in the sub-scanning direction from the second area 27. Referring to FIG. 8, the predetermined area 45 is located in the sub-scanning direction from the second area 27. 8 has the same configuration as that of FIG. 6 except for the predetermined region 45, and therefore, the same reference numerals are given and description thereof is omitted.

  Further, a region setting means for setting a predetermined region may be provided in the operation unit 13, and the region set from the operation unit 13 may be used. In this way, a predetermined area can be set according to the convenience of the user.

  In the above embodiment, the example in which the predetermined value of the density difference is 100 has been described. However, the present invention is not limited to this, and other values may be used.

  In the above embodiment, the example has been described in which the first region 26 is located at the left end of the first page 31 and the second region 27 is located at the left end of the second page 32. However, the position is not limited to this and may be other positions. For example, in FIG. 2, when the background density is detected by moving in the direction from the second page 32 to the first page 31, the first area is the right end of the first page 31, that is, the entire spread original 25. For example, the center portion and the second region may be located at the right end portion of the second page 32, that is, the end portion of the spread document 25 as a whole.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

1 is a block diagram illustrating a configuration of a digital multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral. 1 is a schematic view of an image reading device provided in a digital multi-function peripheral as viewed from above. FIG. 3 is a schematic view of the image reading apparatus shown in FIG. 2 viewed from the lateral direction indicated by an arrow A. It is the enlarged view to which the 1st area | region shown with the dashed-dotted line in FIG. 2 was expanded. 6 is a flowchart illustrating a case where an image is formed using a copy function of a digital multifunction peripheral. FIG. 6 is a diagram illustrating an example in which a spread original is placed at a position slightly deviated from a reference position in the sub-scanning direction. It is a figure which shows a predetermined area | region. It is a figure which shows the example which provided the predetermined area | region so that it might be located in a subscanning direction from a 2nd area | region. It is the figure which looked at the mounting base which mounted the facing original from the horizontal direction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Digital multifunction device, 11 Control part, 12 DRAM, 13 Operation part, 14 Document feeder, 15 Image reading part, 16 Image formation part, 17 Hard disk, 18 FAX communication part, 19 Network IF part, 20 Public line, 21 Network , 22 PC, 23 Image reading device, 24 Placement table, 25, 40 Spread document, 26, 27, 44, 45 area, 28 Light source, 29, 41 Binding unit, 30 Optical unit, 31, 42 First page, 32, 43 page 2, 33 lines.

Claims (3)

An image forming apparatus that adjusts a background density of an image to be formed based on a background density of a read document,
Placing means for placing a double-paged document with the side of the book open as a document;
Of the two-page spread document placed on the placing means, an end portion of the two-page spread document, a first region located on the first page on one side, and a center portion of the two-page spread document, Detecting means for detecting the background density of the second region located on the second page on the other side;
Discriminating means for discriminating whether or not the density difference between the background density of the first area and the background density of the second area detected by the detecting means is a predetermined value or more;
Adjusting means for adjusting the background density of the image to be formed,
The detecting means, when the determining means determines that the density difference is greater than or equal to the predetermined value, the background density of a predetermined area that is located on the second page and includes an area different from the second area Detect
The adjusting means adjusts the background density of the image to be formed based on the background density of the predetermined area detected by the detecting means ,
In the image forming apparatus , the detection unit moves in a direction from the first page toward the second page in the region to detect a background density and select a lightest density . The image forming apparatus according to claim 1 , wherein the predetermined area is an area located in a direction in which the detection unit moves from the second area. It comprises region setting means for setting the predetermined area, the image forming apparatus according to claim 1 or 2.

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