JP5267108B2 - Image processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor for correctly determining whether or not an original document in non-standard size is a color in comparison with the case that it has a configuration different from this invention in the image processor which is provided with a reverse side dedicated reading sensor in a position facing a carrier path and an original document carrying part for reading the surface and the reverse side without stopping the original document to be carried. <P>SOLUTION: The image processor has: a reading means for reading the surface and the reverse side of the original document; a standard size determination means for determining a standard size of a recording medium for copying and printing the original document; a first output means for outputting reverse side image information on the original document read by the reading means; a second output means for temporarily storing reverse side information output by the first output means, rotating it at 180 degrees, and outputting rotated image information in an area in a standard size determined by the standard size determination means; and a color detection means for selecting an output result of either the first output means or the second output means and detecting whether or not an image in the area in standard size determined by the standard size determination means is a color image. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an image processing apparatus.

  In an image processing apparatus provided with a document conveyance unit that conveys documents one by one along a conveyance path, a CIS (Contact Image Sensor) is provided at a position facing the conveyance path (document traveling surface). In some cases, a reading sensor dedicated to the back side is provided, and the document being conveyed is scanned simultaneously without stopping the document being conveyed.

  In an image processing apparatus provided with such a document transport unit, image processing is performed on the back side image by the image processing dedicated IC, and then temporarily stored in the memory. After the front side image is transmitted to the controller, it is stored in the page memory. In many cases, the back side image is transmitted to the reading controller.

  When this page memory is read out, the back side image needs to be output by rotating the image 180 degrees depending on the “upward direction” or “opening direction” of the document. This is to optimize the arrangement and orientation of the output copy so that it can be easily viewed by the user.

  The color reader also performs ACS (Auto Color Selection) detection that automatically determines whether a document is monochrome or color.

Patent Document 1 discloses a technique for preventing erroneous determination such as chromatic / achromatic color for an area that can be set in line units from the rear end portion of an original with an irregular size or mixed size.
JP 2006-29584 A

  The present invention provides an image processing apparatus provided with a back surface dedicated reading sensor at a position facing a transport path, and having a document transport unit that reads the front and back surfaces without stopping the document being transported. An object of the present invention is to provide an image processing apparatus that correctly determines whether or not a color is present.

  In order to achieve the above object, the invention of claim 1 provides a reading means for reading the front and back surfaces of a document from a document placed on a document table, and a standard size of a recording medium for copying and printing the document. A fixed size determining means for determining, a first output means for outputting the back side image information of the original read by the reading means, and the back side image information output by the first output means are temporarily stored and rotated 180 degrees, The second output means for outputting the rotated image information of the area for the fixed size determined by the fixed size determining means, and the output result of either the first output means or the second output means is selected to determine the fixed size. Color detecting means for detecting whether or not the image of the area for the fixed size determined by the means is a color image.

  According to a second aspect of the present invention, in the first aspect of the invention, the color detection unit detects whether the back image is a color image when the back image is printed on the recording medium. Is.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the color detection means determines whether the rotated image is a color image when the rotated image is printed on the recording medium. Is to detect.

  According to a fourth aspect of the present invention, in the invention of the third aspect, the color detection means is configured such that, when the back surface image information is image information that is irreversibly compressed, the back surface image information is irreversibly compressed. The detection accuracy is increased as compared with the case where there is not.

The invention of claim 5 further comprises an actual size detecting means for detecting the actual size of the document in the sub-scanning direction according to any one of claims 1 to 4, and the color detection. When the detection result by the actual size detection unit is found before the reading of the back surface is started by the reading unit, the unit detects a region that matches the output region for the standard size in the back surface image information. Set as an area, detect whether the back image is a color image in the set detection area, and the detection result by the actual size detection means is found after the reading of the back surface by the reading means is started In this case, it is detected whether or not the rotated image is a color image.

  In order to achieve the above object, the invention of claim 6 provides a reading means for reading a front surface and a back surface of a document from a document placed on a document table, and a standard size of a recording medium for copying and printing the document. A fixed size determining means for determining; a first output means for outputting back side image information of a document read by the reading means; and a case where the back side image is an image used when copying and printing a document. First color detection means for detecting whether or not the image of the area for the fixed size determined by the fixed size determination means for the back image is a color image, and the back image information output by the first output means. Second output means for temporarily storing the corresponding back image, rotating it 180 degrees, and outputting the rotated image information of the area for the fixed size determined by the fixed size determining means; and the rotated image In the case of an image used when copying and printing a document, a second color for detecting whether or not an image of a region for the fixed size determined by the fixed size determining means of the rotated image is a color image. Detecting means.

  Further, in the invention of claim 7, in the invention of claim 6, when the back surface image information is irreversibly compressed, the second color detecting means performs irreversible compression of the back surface image information. Compared with the case where it is not performed, the detection accuracy is increased.

The invention of claim 8 is detected in the invention of claim 6 or 7, by further comprising, before you size detection means actual size detection means for detecting the actual sub-scanning direction size of the document If the result is found before the reading unit starts reading the back side, the first color detecting unit sets a region that matches the output area for the standard size in the back side image information as a detection region. Set and detect whether the back image is a color image in the set detection area, and the detection result by the actual size detection means is found after the reading of the back surface by the reading means is started in this case, the second color sensing unit, the rotated image is intended to detect whether or not a color image.

  According to the first or sixth aspect of the present invention, in the image processing apparatus, the back-side dedicated reading sensor is provided at a position facing the conveyance path, and the document conveying unit reads the front and back surfaces without stopping the document being conveyed. As compared with the case where this configuration is not provided, it is possible to provide an image processing apparatus that correctly determines whether or not a non-standard-size document is in color.

  According to the second and third aspects of the invention, since it is detected whether the image to be printed on the recording medium is a color image or not, a document having a non-standard size is compared with a case where this configuration is not provided. It is possible to provide an image processing apparatus that correctly determines whether or not a color is present.

  According to the fourth and seventh aspects of the present invention, when irreversible compression is performed, the resolution of the color image is lowered. Therefore, the accuracy of determining whether or not the color is increased is increased, so that this configuration is not provided. Thus, it is possible to provide an image processing apparatus that correctly determines whether or not a non-standard-size document is in color.

  According to the fifth and eighth aspects of the present invention, when the detection result by the actual size detection means is found before the reading of the back surface is started by the reading means, it is compared with the case without this configuration. Thus, it is possible to more quickly detect whether the image is a color image.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, the overall configuration of the image processing apparatus 10 according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 1, the image processing apparatus 10 includes a document conveying unit 12 and an image reading unit 14.

  The document transport unit 12 includes a document table 20 on which a document 18 on which an image is recorded is placed. The documents 18 placed on the document table 20 are picked up one by one by a pick-up roll 22 and are fed to a document transport path 24. Sent.

  The document 18 sent to the document transport path 24 is transported to the front surface reading position by the image reading unit 14 by the transport roller pair 26, and after the surface is read by the image reading unit 14, the downstream side in the transport direction from the front surface reading position. Then, the back side is read by the back side image reading unit 28 and then discharged to the paper discharge unit 30.

  The back image reading unit 28 includes a plurality of light emitting elements arranged along the main scanning direction in which a reading surface 28A for reading a document is provided on the document conveyance path side and the document 18 is irradiated with illumination light. And a line sensor that divides the original 18 illuminated by the light source into a plurality of pixels and measures the light, and outputs pixel value information corresponding to the pixel values measured for each pixel.

  The document conveying unit 12 and the image reading unit 14 described above can be opened and closed above the image reading unit 14 around a support shaft (not shown). That is, as in a general image forming apparatus, the lower surface of the document conveying unit 12 is exposed to the user. Further, a standard size detection sensor 46 is provided in the document conveying unit 12. The fixed size detection sensor 46 detects a fixed size that best fits the size of the document, and a controller described later determines the fixed size of the recording medium on which the document is copied and printed from the detection result. .

  The image reading unit 14 includes a transparent platen glass 32 on which an original 18 can be placed on the upper surface, and the surface reading position is located on the upper surface of the platen glass 32.

  Below the platen glass 32 at the surface reading position, a light source 34 that irradiates illumination light toward the surface of the document 18, a first reflection mirror 36 that receives reflected light reflected on the surface of the document 18, and a first reflection mirror A second reflecting mirror 38 for bending the traveling direction of the reflected light received at 36 by 90 °, and a third reflecting mirror 40 for further bending the traveling direction of the reflected light received by the second reflecting mirror 38 by 90 °. ing.

  The image reading unit 14 includes a lens 42 and a light detection unit 44 including a plurality of pixels. The image reading unit 14 causes reflected light reflected by the third reflection mirror 40 to be reflected by the lens 42. The surface of the document 18 is read by forming an image on the light detection unit 44. The light detection unit 44 and the back image reading unit 28 read the front and back surfaces of the document from the document placed on the document table.

  The image processing apparatus 10 according to the present embodiment uses a fluorescent lamp as the light source 34, but is not limited to this, and a plurality of LEDs (Light Emitting) arranged along the direction intersecting the conveyance direction of the document 18. Other light sources such as Diode) may be applied.

  In the image processing apparatus 10 according to the present embodiment, a CCD line sensor composed of a plurality of CCDs (Charge Coupled Devices) is applied as the light detection unit 44. However, the present invention is not limited to this, and a CMOS (Complementary Metal-Oxide) is used. Semiconductor) A solid-state imaging device such as an image sensor may be applied.

  In the image processing apparatus 10 according to the present embodiment, the light source 34, the first reflecting mirror 36, the second reflecting mirror 38, and the third reflecting mirror 40 are movable in the direction of arrow C in FIG. As a result, when the document conveying unit 12 is opened above the image reading unit 14 and the document 18 is placed on the upper surface of the platen glass 32, the illumination light is emitted from the light source 34 toward the document 18 and the arrow A By moving the light source 34, the first reflecting mirror 36, the second reflecting mirror 38, and the third reflecting mirror 40 in the direction, it is possible to read the image recorded on the document 18.

  Next, the hardware configuration of the image processing apparatus 10 will be described with reference to FIG. The image processing apparatus 10 mainly includes a controller 50, an image reading control unit 52, a document conveying unit control unit 54, a back image reading control unit 56, a CCD 58, and a UI (User Interface) 60.

  Among these, the controller 50 controls the entire image processing apparatus 10. The controller 50 also receives image signals from the image reading control unit 52 and the back surface image reading control unit 56, and receives user instructions and the like from the UI 60. The UI 60 also has a display screen for displaying information to the user. Further, the controller 50 is provided with an output switching unit 90. Details of the output switching unit 90 will be described later.

  The image reading control unit 52 controls the entire image reading process in the image processing apparatus 10. The document reading unit control unit 54, the back image reading control unit 56, the CCD 58, the scanning control unit 72, and the illumination control unit 76. Etc. are controlled.

  Specifically, the image reading control unit 52 has a function of controlling image reading on the front side of the document in accordance with a reading instruction from the controller 50, performing image processing, and sending an image to the controller 50.

  The image reading control unit 52 can access a surface ROM (Read Only Memory) 68. The front surface ROM 68 stores various programs for reading the surface of the original, various information used at that time, and the like.

  Further, the image reading control unit 52 is provided with a surface image reading processing unit 94. Details of these will be described later.

  Note that the scanning control unit 72 performs control related to scanning when reading a document, and also controls the motor 74. This motor 74 is a motor that integrally moves the light source 34 and various mirrors described in FIG. The illumination control unit 76 controls the lamp 78 including the light source 34.

  The document conveyance unit control unit 54 controls the document conveyance unit 12, and includes each roller control unit 64 that controls each motor 66 for rotating the roll 22 and the conveyance roll pair 26 described above, and each sensor 62. Receive the information.

  Further, the back surface image reading control unit 56 controls the back surface contact sensor 80 included in the back surface image reading unit 28 according to an instruction from the image reading control unit 52, and performs reading control on the back side to perform image processing. In addition, it has a function of sending image information to the controller 50.

  Further, the back surface image reading control unit 56 can access the back surface ROM 82. The back ROM 82 stores a program for operating the back image reading control unit 56 and the like.

  The back image reading control unit 56 is provided with a back image reading processing unit 84, a page memory control unit 86, and a page memory 88. Details of these will be described later.

  Next, among the configurations described above, a main configuration particularly related to the present embodiment will be described. There are three types of this configuration, and the arrangement of the ACS section described later is different.

  First, the main configuration (No. 1) will be described with reference to FIG. The back surface contact sensor 80 shown in the figure outputs back surface image information corresponding to a back surface image that is an image of the back surface of the document read by the reading unit. The back surface image information read by the back surface contact sensor 80 is output to the back surface image reading processing unit 84. Image processing is performed by the image processing unit 96 that outputs back side image information corresponding to the back side image which is the back side image of the read original. The image processing unit 96 outputs the back-side image information subjected to the image processing to the page memory control unit 86.

  The page memory control unit 86 stores the image information output from the image processing unit 96 in the page memory 88. Then, the page memory control unit 86 temporarily stores the back side image information output by the image processing unit 96, rotates the back side image information by 180 degrees, and outputs rotated image information of the determined standard size area. In this case, it is assumed that the fixed size of the recording medium on which the original is copied and printed is determined from the detection result of the fixed size detection sensor 46.

  The ACS unit 102 detects whether or not the image of the area for the determined standard size is a color image among the rotated images indicating the rotated image information output from the page memory control unit 86.

  On the other hand, the surface image information indicating the surface image read by the CCD 58 is subjected to image processing by the surface image reading processing unit 94.

  The output switching unit 90 outputs any one of the back surface image information stored in the page memory 88 and the front surface image information from the front surface image reading processing unit 94 to the controller 50. The image information output to the controller 50 is information indicating an image that is actually printed on the recording medium. Therefore, the ACS detection area implemented by the ACS unit 102 matches the image area to be actually printed.

  Next, the main configuration (No. 2) will be described with reference to FIG. The configuration shown in FIG. 4 is different from the configuration shown in FIG. 3 in that the ACS unit 98 is arranged in the back image reading processing unit 84 and the selection unit 100 is further added.

  The selection unit 100 selects one of the back image information output from the image processing unit 96 and the rotation image information output from the page memory control unit 86, and outputs one image information to the ACS unit 98. Output.

  Accordingly, the ACS unit 98 detects whether or not the area for the standard size of the back image is a color image when printing the back image not subjected to the 180 ° rotation process on the recording medium, and performs the 180 ° rotation process. In the case where a rotated image to be subjected to printing is printed on a recording medium, it is detected whether or not a region for the fixed size of the rotated image is a color image. Therefore, the ACS detection area executed by the ACS unit 98 coincides with the image area to be actually printed.

  Next, the main configuration (No. 3) will be described with reference to FIG. The configuration shown in FIG. 5 is a configuration in which two ACS units 98 and 102 are provided. Among these, the ACS unit 98 detects whether or not an area for the standard size of the image is a color image when a back image not subjected to the 180 degree rotation process is printed on the recording medium. On the other hand, the ACS unit 102 detects whether or not the area of the standard size part of the rotated image is a color image when a rotated image to be rotated 180 degrees is printed on a recording medium.

  The above are three examples of the main configuration particularly related to the present embodiment. Hereinafter, specific processing will be described. First, processing generally performed when the back side image is read by the document conveying unit 12 will be described with reference to FIG.

  FIG. 6 shows a state in which a document having F printed on the front surface and R printed on the back surface is set on the document conveying unit 12, a front surface read image, a back surface read image, a front surface output image, and a back surface output image. Yes. Among these, the front side read image and the back side read image indicate images read by scanning the front side and the back side of the document, respectively. Further, the front surface output image and the back surface output image indicate images printed on the front surface and the back surface of the recording medium, respectively.

  As shown in the figure, when the back side is read by the document conveying unit 12, an image obtained by inverting the front side read image as a mirror image is used as a front side output image, and an image obtained by rotating the back side read image by 180 degrees is used as a back side output image.

  Next, a detection area for detecting whether or not the ACS unit is a color will be described with reference to FIG. This figure shows a case where an image is read from a standard size document (A) and a case where an image is read from a non-standard size document which is larger than the standard size (B).

  The detection area of the ACS unit is a shaded area in any case. Therefore, the ACS unit detects whether or not the image of the area for the determined standard size is a color image. As a result, in (B), if a color image exists outside the detection area, it is erroneously determined as a black and white image.

  Next, a method for outputting image information indicating an image rotated by 180 degrees in the page memory control unit 86 will be described. In the following description, the page memory 88 is simply indicated as a memory.

  FIG. 8 shows a memory area and an area in which image information is written in the memory area. FIG. 4A shows the memory write time, and FIG. 4B shows the memory read time.

  As shown in FIG. 5A, the page memory control unit 86 starts writing image information read with the regular main scanning width and with the actual document sub-scanning width. On the other hand, at the time of memory reading, the page memory control unit 86 starts reading in the reverse direction from the final pixel position at the time of writing. In addition, since the page memory control unit 86 finishes reading with the fixed main scanning width, there is an area that is not read (area that is not output).

  A problem example (part 1) that occurs when image information is output by this method will be described with reference to FIG.

  In FIG. 9, a document larger than a standard size drawn with F on the front side and R on the back side is set on the document transport unit 12 (the document is placed with “top up” and “left and right open”). ), A front side read image, a back side read image, a front side output image, and a back side output image are shown. Among these, the front side read image and the back side read image indicate images read by scanning the front side and the back side of the document, respectively. Further, the front surface output image and the back surface output image indicate images printed on the front surface and the back surface of the recording medium, respectively. In addition, an ACS detection area in which the ACS unit detects whether the color is present and an output area output by the page memory control unit 86 are shown. Furthermore, in the figure, the star in the figure is colored.

  As shown in the figure, since the surface image is a mirror image inversion, there is no problem because the ACS portion detection area matches the output area. However, since the back image is rotated by 180 degrees, as shown in the figure, the ACS portion detection area and the output area do not coincide with each other, so that the back scan image (the ACS detection area does not include a star) and the back surface The detection result of the ACS part of the output image (the star detection is included in the ACS detection area) is different. In this case, if detection by the ACS unit is performed on the back side read image, the detection result is black and white. However, since the actually printed recording medium includes color, the color is erroneously determined to be black and white. Black and white printing will be performed.

  In order to solve this, in the three types of configurations described above, detection by the ACS unit is performed on the back image that has been subjected to the 180-degree rotation process. Specifically, in the main configuration (part 1) and the main configuration (part 3), the ACS unit 102 is controlled to detect. In the main configuration (part 2), the selection unit 100 controls the ACS unit 98 to perform detection by selecting the rotated image information output from the page memory control unit 86.

  By this control, as shown in the back side output image of FIG.

  Next, a problem example (No. 2) will be described with reference to FIG. FIG. 11 shows a state in which a document drawn with “F” on the front side and “R” on the back side is set on the document transporting portion 12 (the document is placed with “top down” and “open left and right” is indicated), A read image, a back surface read image, a front surface output image, and a back surface output image are shown. Among these, the front side read image and the back side read image indicate images read by scanning the front side and the back side of the document, respectively. Further, the front surface output image and the back surface output image indicate images printed on the front surface and the back surface of the recording medium, respectively. In addition, an ACS part detection area for detecting whether the ACS part is color or not and an output area output by the page memory control part 86 are shown. Furthermore, in the figure, the star in the figure is colored.

  As shown in the figure, since the surface image is a mirror image inversion, there is no problem because the ACS portion detection area matches the output area. However, since the back image is rotated by 180 degrees, as shown in the figure, the ACS portion detection area and the output area do not coincide with each other, so the back read image (the ACS detection area includes a star) and the back output The detection results of the ACS portion of the image (the star detection mark is not included in the ACS detection area) are different. In this case, if detection by the ACS unit is performed on the back side scanned image, the detection result is color, but since the actually printed recording medium does not include color, black and white is erroneously detected as color. Color printing.

  In order to solve this, in the three types of configurations described above, detection by the ACS unit is performed on the back image that has been subjected to the 180-degree rotation process. Specifically, in the main configuration (part 1) and the main configuration (part 3), the ACS unit 102 is controlled to detect. In the main configuration (part 2), the selection unit 100 controls the ACS unit 98 to perform detection by selecting the rotated image information output from the page memory control unit 86.

  By this control, as shown in the back side output image of FIG.

  In order to reduce the capacity of the page memory 88, the resolution may be reduced and the amount of data may be reduced for storage. In the case of this irreversible compression, the rotated image information read by the page memory control unit 86 is image information indicating an image with a low resolution. Therefore, there is a high possibility that the ACS unit erroneously determines a thin color line or the like. Become.

  At this time, in order to ensure the detection accuracy of the ACS unit, the parameter used in the ACS unit is changed to a parameter that increases the detection accuracy. Further, since the direction of detection by the ACS unit changes when rotated 180 degrees (see FIG. 8), it is necessary to change the parameter depending on the direction. That is, in the case of image information that is irreversibly compressed, control is performed such that the detection accuracy is higher than that in the case where the back surface image information is not irreversibly compressed.

  Specifically, in the main configuration (part 1) and the main configuration (part 3), control is performed so as to increase the detection accuracy of the ACS unit 102. In the main configuration (No. 2), when the selection unit 100 selects the rotated image information output from the page memory control unit 86, control is performed so that the detection accuracy of the ACS unit 98 is increased.

  Even if the actual size is not known before reading, ACS detection may be performed first on the back image. This is because when the actual size is detected later and the actual size is a standard size or almost the standard size, no erroneous detection occurs even if the ACS detection is performed on the back image, and as a result, the ACS detection is performed on the rotated image. This is because the ACS detection result can be obtained earlier and more accurately.

  Next, a description will be given of a case where the actual size of the original in the sub-scanning direction (sub-scanning length) may be determined before the reading of the back side is started. For example, in the case where the document conveying unit 12 is a large apparatus, the conveyance path becomes long, so that it may be found before reading of the back surface is started.

  In the case of the main configuration 1, since the detection is performed with respect to the rotated image information output from the page memory control unit 86, the later part of the determination is irrelevant.

  When it is determined before the reading of the back side is started, the position of the trailing edge of the document is determined before the reading, so that it is possible to set an ACS detection area that matches the output area in advance. Therefore, in the main configuration (part 2), the selection unit 100 selects the back side image information output from the image processing unit 96, and the ACS unit 98 detects whether the back side image is a color image.

  Similarly, when it is determined before reading of the back surface is started, in the main configuration (part 3), the ACS unit 98 determines whether or not the back image indicated by the back image information output from the image processing unit 96 is a color image. Detect.

  On the other hand, when it is determined after the reading of the back side is started, the position of the trailing edge of the document is not fixed before the reading, so that it is not possible to set the ACS detection area that matches the output area in advance. Therefore, in the main configuration (part 2), the selection unit 100 selects the rotated image information output from the page memory control unit 86, and the ACS unit 98 detects whether or not the rotated image is a color image. .

  Similarly, when it is determined after reading of the back surface is started, in the main configuration (part 3), the ACS unit 102 determines whether or not the rotated image indicated by the rotated image information output from the page memory control unit 86 is a color image. Detect.

  This will be specifically described with reference to the timing charts of FIGS. FIG. 13 shows a timing chart when it is determined before reading of the back surface is started, and FIG. 14 is a timing chart when it is determined after reading of the back surface is started.

  In any of the figures, the front image sub-scanning length, the back-side image sub-scanning length as the memory writing length, the ACS portion detection area at the time of memory writing, and the back-side that is the rotation image information length output from the page memory control unit 86 The memory read length and the write or read timing in the ACS part detection area at the time of memory read are shown.

  In FIG. 13, as shown in “document sub-scanning length confirmation”, the trailing edge position of the document is determined before the reading of the back side is started, so the ACS detection area is “detection” before the page memory writing is started. At the time of “area setting 1”, a memory area indicating an image to be actually printed is set. Therefore, from the timing when writing to the memory indicated by the back image sub-scanning length is started, after the writing of the “non-read region” shown in FIG. The detection result is confirmed.

  On the other hand, in FIG. 14, as indicated by “Confirm original sub-scanning length”, it is determined after the reading of the back side is started. A predetermined size is set from the position. Therefore, detection is started from the timing when writing to the memory indicated by the back image sub-scanning length is started, and the detection result in that region is determined. In this case, the “non-read region” shown in FIG. 8 becomes a detection region, and a region different from the output region is detected. Therefore, at the time of “detection area setting 2” immediately after the writing to the page memory control unit 86 is completed and the document sub-scanning length is determined, a predetermined size from the last pixel position at the time of writing is set as the ACS detection area. In the main configuration (part 2), the above setting is performed in the ACS unit 98, and in the main configuration (part 3), the ACS unit 102 is set. At this time, in the main configuration (part 2), the selection unit 100 selects the output of the page memory control unit 86. Based on the output of the page memory control unit 86, the detection result of whether or not the color is present is determined.

1 is a diagram illustrating an overall configuration of an image processing apparatus according to an embodiment. It is a figure which shows the hardware constitutions of an image processing apparatus. It is a figure which shows main structures (the 1). It is a figure which shows main structures (the 2). It is a figure which shows main structures (the 3). FIG. 10 is a schematic diagram illustrating an example of processing that is generally performed when a back surface image is read by a document transport unit. It is a figure which shows the detection area | region which detects whether an ACS part is a color. It is a figure which shows the area | region where image information is written in a memory area and a memory area. It is a figure which shows a malfunction example (the 1). It is a figure which shows that the ACS part detection area | region and the output area corresponded. It is a figure which shows a malfunction example (the 2). It is a figure which shows that the ACS part detection area | region and the output area corresponded. It is a figure which shows a timing chart in case an actual subscanning length becomes clear before the reading of a back surface is started. It is a figure which shows a timing chart in case the actual subscanning length becomes clear after the back surface reading is started.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image processing apparatus 12 Original conveyance part 14 Image reading part 20 Original stand 24 Original conveyance path 28 Back surface image reading part 44 Photodetection part 46 Standard size detection sensor 50 Controller 52 Image reading control part 54 Original conveyance part control part 56 Back surface image reading Control unit 80 Back surface adhesion sensor 84 Back surface reading processing unit 86 Page memory control unit 88 Page memory 90 Output switching unit 94 Front surface image reading processing unit 96 Image processing unit 98, 102 ACS unit 100 Selection unit

Claims (8)

Reading means for reading the front and back surfaces of the document from the document placed on the document table;
A fixed size determining means for determining a fixed size of a recording medium on which the original is copied and printed;
First output means for outputting back side image information of the document read by the reading means;
Second output means for temporarily storing the back side image information output by the first output means, rotating it 180 degrees, and outputting rotated image information of the area for the standard size determined by the standard size determination means;
A color detection unit that selects an output result of either the first output unit or the second output unit, and detects whether or not an image of a region for the fixed size determined by the fixed size determination unit is a color image; ,
An image processing apparatus.   The image processing apparatus according to claim 1, wherein when the back image is printed on the recording medium, the color detection unit detects whether the back image is a color image.   The image processing apparatus according to claim 1, wherein the color detection unit detects whether the rotated image is a color image when the rotated image is printed on the recording medium.   The color detection means increases detection accuracy when the back image information is irreversibly compressed image information as compared to when the back image information is not irreversibly compressed. The image processing apparatus described. An actual size detecting means for detecting the actual size of the original in the sub-scanning direction;
When the detection result by the actual size detection unit is found before the reading of the back side is started by the reading unit, the color detection unit matches the output area for the standard size in the back side image information. An area is set as a detection area, and it is detected whether or not the back image is a color image in the set detection area, and the detection result by the actual size detection means is read by the reading means. The image processing apparatus according to any one of claims 1 to 4, wherein the image processing apparatus detects whether or not the rotated image is a color image when the image is found after the operation. Reading means for reading the front and back surfaces of the document from the document placed on the document table;
A fixed size determining means for determining a fixed size of a recording medium on which the original is copied and printed;
First output means for outputting back side image information of the document read by the reading means;
When the back image is an image used when copying and printing a document, it is detected whether or not the image of the area for the standard size determined by the standard size determining means of the back image is a color image. First color detecting means for
A second output for temporarily storing a back image corresponding to the back image information output by the first output means, rotating the back image by 180 degrees, and outputting rotated image information of the area for the standard size determined by the standard size determining means. Means,
When the rotated image is an image used when copying and printing a document, it is detected whether or not the image of the area for the fixed size determined by the fixed size determining means of the rotated image is a color image. Second color detecting means for
An image processing apparatus.   The second color detection means increases the detection accuracy when the back surface image information is image information that is irreversibly compressed as compared to when the back surface image information is not irreversibly compressed. 6. The image processing apparatus according to 6. An actual size detecting means for detecting the actual size of the original in the sub-scanning direction;
Before you size detection means according to the detection result, wherein when it is found before the back side of the reading is started by the reading means, the first color sensing unit, the output region of the standard size of in the rear surface image information Is set as a detection area, and in the set detection area, it is detected whether the back image is a color image, and the detection result by the actual size detection means is detected by the reading means. If it is found after the reading is started, the second color sensing means, image according to any one of claims 6 or claim 7 wherein the rotated image is detected whether or not a color image Processing equipment.

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