JP2018152780A - Image reading device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify the ends of a read image irrespective of the characteristics of an object image designated as a reading object.SOLUTION: An image reading device comprises: a reading part that reads an object image designated as a reading object; an opposing plate that is provided opposite to the reading part and can display an opposing image on the reading part side; and a control part. When the object image of the object between the reading part and opposing plate is read by the reading part, the control part displays, on the opposing plate, the opposing image in a specified pattern in which a relative position to the object image is not changed, and detects the boundary between a read image corresponding to the object image in an image (123) read by the reading part and a background image corresponding to the opposing image, thereby specifying the ends of the read image.SELECTED DRAWING: Figure 16

Description

  The present invention relates to an image reading apparatus and an image forming apparatus, and more particularly to an image reading apparatus including a counter plate provided to face a reading unit and an image forming apparatus including the image reading apparatus.

  2. Description of the Related Art Conventionally, in an image reading apparatus, a counter plate provided to face a reading unit is black. In such an image reading apparatus, an image with a black frame is read when the original image shown on the paper to be read is read. When the edge of the paper on which the document image is shown is other than black, for example, white, the edge of the read image corresponding to the document image can be detected by comparison with the black frame. By detecting the edge of the read image, it is possible to detect the amount of inclination and the amount of deviation of the image. For this reason, by performing image processing on the read image based on the tilt amount and the offset amount, it is possible to output image data in which the tilt and the offset are corrected.

  However, when the edge of the paper on which the document image is shown is black, the edge of the read image corresponding to the document image cannot be distinguished from the black frame of the read counter plate. For this reason, the end of the read image corresponding to the document image cannot be determined. For this reason, the inclination and the deviation cannot be corrected. Further, it is impossible to crop unnecessary portions other than the read image.

  In order to solve such a problem, there is one in which the counter plate can be switched to white or black by electrical control (see, for example, Patent Document 1). According to the apparatus of Patent Document 1, when reading a document, the counter plate is switched to black, the boundary between the document and the background is recognized, and the size and inclination of the document are detected. In addition, the counter plate is switched to black in order to prevent document show-through. When the size and inclination of the document are not detected, and when the show-through of the document is not prevented, the facing plate is switched to white.

JP 2007-309969 A

  FIG. 18 is a diagram showing an image as a result of reading a conventional document. FIG. 19 is a diagram showing an image obtained by cropping an image obtained as a result of conventional reading. FIG. 20 is a diagram showing an image of a missing portion in reading of a conventional document.

  Referring to FIGS. 18 to 20, as shown in FIG. 18, the image 11A portion of the read image 12 is a portion corresponding to the original image. Here, the color of the opposing plate is black, and the portion of the frame in contact with the edge of the image of the document is the same black. Note that the lattice lines corresponding to the opposing plate in the image 12 in FIG. 18 are merely shown for convenience so that the portion corresponding to the opposing plate can be seen. The line is not drawn.

  For this reason, cropping a portion determined to be an unnecessary portion yields an image obtained by removing the frame portion in contact with the end portion from the document image as shown in FIG. As a result, the portion of the image 14 shown in FIG. 20 in the original image is lost.

  As described above, the technique disclosed in Patent Document 1 has a problem that the end of the read image cannot be specified depending on the color of the end of the image to be read.

  The present invention has been made to solve the above-described problems, and one of the objects of the present invention is to specify the end of the read image regardless of the characteristics of the target image indicated on the read target. An image reading apparatus and an image forming apparatus are provided.

  In order to achieve the above-described object, according to one aspect of the present invention, an image reading apparatus includes a reading unit that reads a target image indicated by a reading target, a reading unit, and a reading unit. A counter plate capable of displaying a counter image and a control unit.

  When the target image of the target object between the reading unit and the counter plate is read by the reading unit, the control unit causes the counter plate to display a counter image having a predetermined pattern whose relative position with respect to the target image does not change, and reads the target image. The edge of the read image is specified by detecting the boundary between the read image corresponding to the target image and the background image corresponding to the counter image in the image read by the unit.

  Preferably, the predetermined pattern includes a region having a color different from that of the adjacent region which is parallel to any side of the rectangular opposing image. Preferably, the predetermined pattern includes a region having a color different from an adjacent region that is not parallel to any side of the rectangular opposing image. More preferably, the different color regions are regions having different RGB ratios or densities. Preferably, the predetermined pattern has a resolution equal to or higher than the resolution of the reading unit.

  Preferably, when the read image includes a transparent image of the opposite image, the control unit executes image processing for deleting the transparent image.

  Preferably, when the target image is read by the reading unit while conveying the target object, the control unit is configured to prevent the relative position between the predetermined pattern of the counter image displayed on the counter plate and the target image from changing. Move.

  More preferably, the control unit changes the predetermined pattern of the counter image displayed on the counter plate when the target is not detected even when the tip of the target reaches the reading unit.

  More preferably, when the front and rear end portions in the vicinity of the front end and the rear end of the object are read by the reading unit, the control unit displays a counter pattern with a predetermined pattern on the counter plate, and the front and rear end portions are read by the reading unit. If not, a monochrome image is displayed on the counter plate, and the end of the read image is specified by detecting the four corners of the read image based on the read image corresponding to the leading edge and the trailing edge of the target image.

  More preferably, the image reading apparatus further includes a detection unit that detects the size of the object. The control unit displays a counter image of a predetermined pattern on the counter plate when the front end portion near one corner of the front end of the object is read by the reading unit, and displays a monochrome image when the front end portion is not read by the reading unit. One corner of the read image is detected based on the read image corresponding to the tip of the target image displayed on the counter plate, and the end of the read image is determined based on the detected one corner and the size detected by the detection unit. Identify.

  More preferably, the image reading apparatus further includes a detection unit that detects the size of the object. The control unit detects one side of the read image based on the read image corresponding to the tip of the target image, and near the end of the target object based on the detected one side and the size detected by the detection unit. A counter-pattern image of a predetermined pattern is displayed in accordance with the movement of the object at the corresponding counter-plate position, and a monochrome image is displayed at the position of the counter-plate corresponding to a part different from the vicinity of the end of the object. The edge of the read image is specified by detecting the boundary between the read image and the background image.

  According to another aspect of the present invention, an image forming apparatus includes any one of the image reading positions described above.

  According to the present invention, it is possible to provide an image reading apparatus and an image forming apparatus capable of specifying an end portion of a read image regardless of the characteristics of the target image indicated on the reading target object.

1 is a block diagram illustrating an outline of a configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a diagram illustrating an appearance of an image forming apparatus according to an embodiment. It is a figure which shows the outline of the structure of the scanner part in this embodiment. It is a block diagram which shows a part of structure of the scanner part in this embodiment. It is a figure which shows the outline of the structure of the periphery of a reading position. It is a figure which shows the example of a display of an opposing board. It is a figure which shows an example of the reading result in a linear image sensor. It is a figure which shows the 1st example of the predetermined pattern displayed on an opposing board. It is a figure which shows the image of a document. FIG. 10 is a diagram illustrating an image obtained as a result of reading an image of a document in the case of the first example. It is a figure which shows the image which cropped the image of the reading result in the case of a 1st example. It is a figure which shows the 2nd example of the predetermined pattern displayed on an opposing board. FIG. 10 is a diagram illustrating an image obtained as a result of reading an image of a document in the case of a second example. It is a figure which shows the image which cropped the image of the reading result in the case of a 2nd example. It is a figure which shows the 3rd example of the predetermined pattern displayed on an opposing board. FIG. 10 is a diagram illustrating an image obtained as a result of reading an image of a document in a third example. It is a figure which shows the image which cropped the image of the reading result in the case of a 3rd example. It is a figure which shows the image of the result of the reading of the conventional original. It is a figure which shows the image which cropped the image of the result of the conventional reading. It is a figure which shows the image of the part missing in the reading of the conventional original.

[First Embodiment]
Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a block diagram showing an outline of the configuration of an image forming apparatus 100 according to an embodiment of the present invention. Referring to FIG. 1, an image forming apparatus 100 controls a control unit 110 for controlling the entire image forming apparatus 100, a storage unit 120 for storing predetermined information, and an image forming apparatus 100. An operation unit 130, a display unit 140 for displaying predetermined information of the image forming apparatus 100, a communication unit 160 for communicating with an external apparatus via the private network 900, and a scanner for reading a predetermined image. And a printer unit 30 for printing a predetermined image.

  The storage unit 120 includes a RAM (Random Access Memory) used as a work area necessary for executing a program by the control unit 110 and a ROM (Read Only Memory) for storing a program to be executed by the control unit 110. Including. In addition, a program and data for executing predetermined processing are read from the operation unit 130, the communication unit 160, or the scanner unit 20 and stored in the RAM. Furthermore, a hard disk drive or a memory card may be used as an auxiliary storage device for assisting the storage area of the RAM.

  The operation unit 130 includes a plurality of operation buttons for causing the image forming apparatus 100 to execute a predetermined function, and a touch panel configured on a display of the display unit 140. An operation signal indicating the operation content input to the image forming apparatus 100 by operating the operation button and the touch panel of the operation unit 130 is passed to the control unit 110.

  Display unit 140 includes a liquid crystal display device (hereinafter referred to as “LCD”) having a touch panel on the display. The LCD of the display unit 140 displays an image received from the control unit 110 and indicating the state of the image forming apparatus 100 and the operation buttons on the touch panel. The display unit 140 may include another FPD (Flat Panel Display) such as an EL (Electro-Luminescence) display, a plasma display, or an SED (Surface-conduction Electron-emitter Display) instead of the LCD.

  The communication unit 160 transmits / receives data to / from an external device through a private network 900 using a predetermined protocol. The communication unit 160 transmits data received from the control unit 110 to the outside, and transfers data received from the outside to the control unit 110.

  The scanner unit 20 optically reads visible information on the surface of a paper document or other object (for example, a resin sheet such as a film), and converts the read image into image data. Then, the image data is transferred to the control unit 110.

  The printer unit 30 converts the image data received from the control unit 110 into an image, and prints the image on an object such as a printing paper or a resin sheet.

  The control unit 110 includes an MPU (Micro Processing Unit) and its auxiliary circuit. The control unit 110 controls the storage unit 120, the operation unit 130, the display unit 140, the communication unit 160, the scanner unit 20, and the printer unit 30, and executes predetermined processing according to programs and data stored in the storage unit 120. The data input from the operation unit 130, the communication unit 160, or the scanner unit 20 is processed, and the processed data is stored in the storage unit 120, displayed on the display unit 140, or output from the communication unit 160. The printer unit 30 performs printing.

  The copy function, printer function, scanner function, facsimile function, and communication function of the image forming apparatus 100 are the control unit 110, storage unit 120, operation unit 130, display unit 140, communication unit 160, scanner unit 20, and printer unit 30, respectively. This is realized by the cooperation of each unit of the image forming apparatus 100.

  FIG. 2 is a diagram showing an appearance of the image forming apparatus 100 in this embodiment. Referring to FIG. 2, the image forming apparatus 100 mainly includes a scanner unit 20 in the upper stage, a printer unit 30 in the middle stage, a paper cassette in the lower stage, and the above-described front side of the scanner unit 20. An operation panel 190 including an operation unit 130 and a display unit 140 is provided.

  FIG. 3 is a diagram showing an outline of the structure of the scanner unit 20 in this embodiment. Referring to FIG. 3, the scanner unit 20 includes an automatic document feeder (hereinafter referred to as ADF (Auto Document Feeder)) 10 and a reading device 15.

  The ADF 10 is a sheet-through type automatic document feeder, and is mounted on the scanner unit 20 and conveys the document to reading positions 114 and 115 to be described later for reading the document. The ADF 10 has a paper feed tray 101 for stacking originals before conveyance and a paper discharge tray 109 for discharging originals after conveyance, and between the paper feed tray 101 and the paper discharge tray 109. A document transport path is configured. A guide (not shown) having at least a position facing the reading positions 114 and 115 is provided on the transport path, and the document is transported along the guide.

  A pick roller 102 and a pair of separating rollers 103 are provided at a boundary position between the paper feed tray 101 and the conveyance path. A bundle of documents stacked on the sheet feed tray 101 is fed by a pick roller 102, separated one by one by a pair of separating rollers 103, and sent out to a conveyance path.

  In the following description, the transport direction of the transport path, that is, the paper feed tray 101 side in the direction from the paper feed tray 101 to the paper discharge tray 109 is referred to as “upstream side in the transport direction”, and the paper discharge tray 109 side is referred to as “transport direction”. It may also be called “downstream of”. Further, the upstream side of the transport path may be referred to as “front”, and the downstream side may be referred to as “rear”.

  The transport path is provided with a pair of registration rollers 104 that sandwich the transport path along the transport direction. The document that has been sent to the registration roller 104 on the conveyance path by the separation roller 103 is skew-corrected by the registration roller 104. Then, the original after skew correction is conveyed to the reading position 114 of the scanner unit 20.

  A pair of reading rollers 105 and 106 are provided on the upstream side and the downstream side of the position corresponding to the reading position 114 of the scanner unit 20 in the conveyance path. Due to the rotation of these roller pairs, the conveyed document passes through the reading position 114 of the scanner unit 20 and is conveyed downstream. As a result, the surface of the document facing the reading device 15 is read by the reading device 15. In the following description, the surface of the conveyed document facing the reading device 15 is also referred to as “front surface”, and the opposite surface is also referred to as “back surface”.

  A reading unit 22 is disposed on the downstream side of the conveyance path with respect to the reading roller 106 with the imaging unit facing the back side of the conveyed document. A pair of reading rollers 107 is provided on the downstream side of the reading unit 22. As the reading rollers 106 and 107 rotate, the conveyed document passes through the reading unit 22 and is conveyed downstream. As a result, the back surface of the document passing through the reading position 115 is read by the reading unit 22.

  A discharge roller 108 is provided at a boundary position between the conveyance path and the discharge tray 109. By the rotation of the discharge roller 108, the document that has been transported and whose back side has been read by the reading unit 22 is discharged to the discharge tray 109.

  A pre-reading sensor 113 in the vicinity of the reading position 114 upstream of the reading position 114, in the vicinity of the registration roller 104 upstream of the registration roller 104, and in the vicinity of the separation roller 103 downstream of the separation roller 103 in the conveyance path, respectively. A resist sensor 112 and a separation sensor 111 are arranged. These sensors detect the presence or absence of a document at that position. These sensors are electrically connected to a scanner unit control unit 201, which will be described later, and output to the scanner unit control unit 201 a sensor signal indicating that a document exists in the sensing range.

  The reading device 15 can employ, for example, a CCD (Charged Coupled Device) system. In this case, the reading device 15 includes an exposure lamp 25, a mirror group including a plurality of mirrors 26A to 26C, and a CCD linear image sensor 21 as a reading unit. An image reading glass (not shown) is disposed at the reading position 114. The reading device 15 is not limited to the CCD method, but may be another method, for example, a CIS (Contact Image Sensor). In this case, the linear image sensor 21 is a CMOS (Complementary Metal-Oxide-Semiconductor) method.

  When the original passes through the reading position 114, the exposure lamp 25 irradiates the surface of the original. The light reflected from the surface of the document by the irradiation light is reflected by the mirrors 26 </ b> A to 26 </ b> C, guided to the linear image sensor 21, and received by the linear image sensor 21. The linear image sensor 21 converts the received light signal into RGB data by photoelectric conversion and outputs the RGB data to the scanner unit control unit 201.

  The reading unit 22 includes an exposure lamp (not shown) and a linear image sensor (not shown) similar to those of the reading device 15. When the original passes through the reading position 115, the exposure lamp of the reading unit 22 irradiates the back side of the original. The light reflected from the back side of the document by the irradiation light is guided to the linear image sensor of the reading unit 22 and received by the linear image sensor. The linear image sensor of the reading unit 22 converts the received light signal into RGB data by photoelectric conversion and outputs the RGB data to the scanner unit control unit 201.

  A counter plate 23 is provided on the back side of the document passing the reading position 114. A counter plate 24 is provided on the front side of the document that passes through the reading position 115. The counter plates 23 and 24 are formed of a reflective display element capable of color display. The display surface composed of the reflective display elements of the counter plates 23 and 24 is directed to the linear image sensor side. The opposing plates 23 and 24 may be configured by other devices as long as they can display with a plurality of gradations. For example, the opposing plates 23 and 24 may be configured by a reflective liquid crystal display device. It may be configured by a display device of this type, or may be a device capable of displaying in a plurality of monochrome gradations instead of color display.

  FIG. 4 is a block diagram showing a part of the configuration of the scanner unit 20 in this embodiment. Referring to FIG. 4, the scanner unit 20 includes a scanner unit control unit 201, sensors 202, motor drive units 203, a linear image sensor 21 for the front surface, and a linear image sensor for the reading unit 22 for the back surface. And a counter plate 23 for the front surface and a counter plate 24 for the back surface are provided as part of the configuration.

  The scanner unit control unit 201 controls each unit of the scanner unit 20 such as each motor drive unit 203 in accordance with detection signals from each detection unit such as each sensor 202.

  The opposing plates 23 and 24 are controlled by the scanner unit control unit 201 to display a predetermined image. The linear image sensor 21 and the linear image sensor of the reading unit 22 read the image shown on the original when the original passes through the reading positions 114 and 115, respectively, and the background displayed on the opposing plates 23 and 24. As an image.

  FIG. 5 is a diagram showing an outline of the structure around the reading position 114. FIG. 6 is a diagram illustrating a display example of the counter plate 23. FIG. 7 is a diagram illustrating an example of a reading result by the linear image sensor 21. With reference to FIGS. 5 to 7, an image of a predetermined pattern is displayed on the counter plate 23 before the document passes the reading position 114. The image displayed on the facing plate 23 is a relative position between the image displayed on the facing plate 23 and the image shown on the document as the document is moved in the document transport direction which is the sub-scanning direction. Is moved by the scanner control unit 201 so as not to change.

  Specifically, the predetermined pattern of the image displayed on the opposing plate 23 is scrolled in the sub-scanning direction at a speed that matches the speed of the original in the document transport direction (sub-scanning direction). In the drawings of this embodiment, the difference in color is indicated by the difference in hatching. As a result, an image of one line in the main scanning direction read by the linear image sensor 21 at a certain timing when the original does not reach the reading position 114 becomes an image as shown in FIG.

  The color is determined by the three attributes hue, saturation, and brightness. The difference in color means that at least one of these three attributes is different. The difference in color density means that, for example, at least one of saturation and lightness is different.

  One line in the main scanning direction is read, and after the original is conveyed by one line in the sub-scanning direction, the next one line in the main scanning direction is read. By repeating this reading sequentially, an image of one original is read.

[First Example of Predetermined Pattern Displayed on Opposing Plate 23]
FIG. 8 is a diagram illustrating a first example of a predetermined pattern displayed on the counter plate 23. Referring to FIG. 8, in the first example, the predetermined pattern of the rectangular image 231 displayed on the counter plate 23 is the sub-scanning direction (the long side direction of the image 231) that is one direction of the rectangular side. ) Parallel to both the main scanning direction (short-side direction of the image 231) and the sub-scanning direction, which are the other directions of the rectangular sides, and the regions 231A and 231B having different colors from the adjacent regions. And regions 231C and 231D of different colors from the adjacent regions. An image displayed on the counter plate 23 at a certain time is an image corresponding to the width of the counter plate 23 in the sub-scanning direction in the image 231 having the predetermined pattern.

  Here, the portions of the image 231 other than these regions 231A to 231D are black, but may be other colors. Further, the colors of the areas 231A and 231D are the same and the colors of the areas 231B and 231C are the same, but the areas 231A to 231D may be different colors. Further, one grid of the grid may be one pixel, or a region composed of a plurality of pixels, for example, a rectangle of m × n pixels (m, n ≧ 2, m = n may be satisfied). It may be a region.

  FIG. 9 is a view showing an image 11 of a document. Referring to FIG. 9, in image 11, the color of the area in contact with the end is black. FIG. 10 is a diagram illustrating an image 121 obtained as a result of reading the document image 11 in the case of the first example. Referring to FIG. 10, a part of areas 231 </ b> A to 231 </ b> D having a predetermined pattern on an image 231 displayed on the counter plate 23 is hidden in the image 11 to be read. In FIG. 10, the hidden area is surrounded by a thick line for convenience, but such a thick line is not actually obtained as a result of reading.

  FIG. 11 is a diagram illustrating an image 131 obtained by cropping the read-out image 121 in the case of the first example. Referring to FIG. 11, a portion of the black frame that is in contact with the edge of the image 11 to be read that covers the regions 231 </ b> A to 231 </ b> D having a color different from the black displayed on the counter plate 23 is displayed in the image 11. It can be recognized as a part.

  Thus, when the counter plate 23 is one black color as in the prior art, as shown in FIG. 19, the image 13 obtained as a result of reading has all black frames lost. However, by displaying the image 231 having the predetermined pattern of the first example on the counter plate 23, the missing portion can be reduced.

  Note that the image 131 obtained as a result of reading may be converted as follows. Since the frame portion of the image 131 is black, the missing portion is estimated to be black, which is the color of the predetermined pattern in contact with the missing portion. Further, it is estimated that the original shape of the obtained image 131 is a rectangle. Then, the missing portion may be interpolated as a black region, and the obtained image 131 may be converted as a rectangular image.

[Second Example of Predetermined Pattern Displayed on Opposing Plate 23]
FIG. 12 is a diagram illustrating a second example of the predetermined pattern displayed on the counter plate 23. Referring to FIG. 12, in the second example, the predetermined pattern of the rectangular image 232 displayed on the counter plate 23 is the sub-scanning direction (the long side direction of the image 232) that is one direction of the rectangular side. ) And regions 232A to 232Z having different colors from the adjacent regions.

  Here, it is assumed that the color of one or a plurality of regions 232N among all the regions 232A to 232Z of the image 232 is black, and the color of other regions is other than black. Note that the number of regions between the region 232A and the region 232N and between the region 232N and the region 232Z may be any number. Further, one grid of the grid may be one pixel, or a region composed of a plurality of pixels, for example, a rectangle of m × n pixels (m, n ≧ 2, m = n may be satisfied). It may be a region.

  Assume that the image of the document to be read is the image 11 described with reference to FIG. FIG. 13 is a diagram showing an image 122 obtained as a result of reading the document image 11 in the case of the second example. Referring to FIG. 13, a part of the predetermined pattern areas 232 </ b> A to 232 </ b> Z of the image 232 displayed on the counter plate 23 is hidden in the image 11 to be read. In FIG. 13, the hidden area is surrounded by a thick line for convenience, but such a thick line is not actually obtained as a result of reading.

  FIG. 14 is a diagram illustrating an image 132 obtained by cropping the image 122 as a read result in the case of the second example. Referring to FIG. 14, a portion of the black frame that is in contact with the edge of the image 11 to be read that is hiding a region having a different color from the black region 232 </ b> N displayed on the counter plate 23 is displayed in the image 11. It can be recognized as a part.

  Thus, when the counter plate 23 is one black color as in the prior art, as shown in FIG. 19, the image 13 obtained as a result of reading has all black frames lost. However, by displaying the image 232 having the predetermined pattern of the second example on the counter plate 23, the missing portion can be reduced.

  In addition, you may make it convert the image 132 obtained as a result of reading as follows. Since the frame portion of the image 132 is black, the missing portion is estimated to be black, which is the color of the predetermined pattern in contact with the missing portion. Further, it is estimated that the original shape of the obtained image 132 is a rectangle. Then, the missing portion may be interpolated as a black region, and the obtained image 132 may be converted as a rectangular image.

  Further, the color of the region 232N may be other than black. In this way, even if the color of the frame of the image 11 to be read is black, it is possible to obtain a read result image having no missing portion. For this reason, it is preferable that the color of each area of the predetermined pattern displayed on the counter plate 23 is a color that has a low probability of being used in a portion in contact with the edge of the document image.

  In the second example, the same color area is provided. However, the present invention is not limited to this, and all areas may have different colors. In this way, the missing part can be further reduced.

[Third Example of Predetermined Pattern Displayed on Opposing Plate 23]
FIG. 15 is a diagram illustrating a third example of the predetermined pattern displayed on the counter plate 23. Referring to FIG. 15, in the third example, the predetermined pattern of the rectangular image 233 displayed on the counter plate 23 is the main scanning direction (the short side direction of the image 233) which is one direction of the rectangular side. ) And the other side of the rectangular side (sub-scanning direction (long side direction of the image 233)), and includes regions 233A to 233Z having colors different from the adjacent regions.

  Here, it is assumed that the color of all the regions 232A to 232Z of the image 232 is other than black. Note that the number of regions between the region 233A and the region 233N and between the region 233N and the region 233Z may be any number. Further, one grid of the grid may be one pixel, or a region composed of a plurality of pixels, for example, a rectangle of m × n pixels (m, n ≧ 2, m = n may be satisfied). It may be a region.

  Assume that the image of the document to be read is the image 11 described with reference to FIG. FIG. 16 is a diagram showing an image 123 obtained as a result of reading the document image 11 in the case of the third example. Referring to FIG. 16, a part of the predetermined pattern areas 233 </ b> A to 233 </ b> Z of the image 233 displayed on the counter plate 23 is hidden in the image 11 to be read.

  FIG. 17 is a diagram illustrating an image 133 obtained by cropping the image 123 as a reading result in the case of the third example. Referring to FIG. 17, a portion of the black frame that is in contact with the edge of the image 11 to be read that covers the regions 233 </ b> A to 233 </ b> Z having a different color from the black displayed on the counter plate 23 is displayed in the image 11. It can be recognized as a part.

  Thus, when the counter plate 23 is one black color as in the prior art, as shown in FIG. 19, the image 13 obtained as a result of reading has all black frames lost. However, by displaying the image 233 having the predetermined pattern in the third example on the counter plate 23, the missing portion can be eliminated.

  In the third example, the same color area is provided. However, the present invention is not limited to this, and all areas may have different colors. In this way, the missing part can be further reduced.

[Second Embodiment]
The timing at which the leading edge of the document reaches the reading position 114 can be estimated by detecting the leading edge of the document by a sensor such as the pre-reading sensor 113. However, even when the leading edge of the document reaches the reading position 114, the linear image sensor 21 may not be able to detect the leading edge of the document. For example, if the pattern of the leading edge of the document coincides with a predetermined pattern of the image displayed on the counter plate 23, the leading edge of the document cannot be detected even if the method of the first embodiment is used. In such a case, there is a high possibility that the trailing edge of the document has the same pattern.

  Therefore, when the leading edge of the document cannot be detected by the linear image sensor 21 even when the leading edge of the document reaches the reading position 114, the scanner control unit 201 determines that the leading edge of the document does not reach the reading position 114. The predetermined pattern of the image displayed on the counter plate 23 is changed. Thereby, the possibility that the trailing edge of the document can be detected can be increased.

  Then, based on the document size information detected by each sensor or the document size information set by the user, the edge of the other document is identified and read from the trailing edge of the detected document. The portion corresponding to the image of the document can be cropped from the captured image.

[Third Embodiment]
If the display resolution of the counter plate 23 is lower than the resolution of the linear image sensor 21, the number of colors of the portion corresponding to the image displayed on the counter plate 23 in the read image is reduced. For this reason, it is considered that the probability that any one of the colors of the predetermined pattern displayed on the counter plate 23 is the same as the color of the edge of the document image is increased. If the colors are the same, a defect occurs at the end of the read image.

  For this reason, the image of a predetermined pattern is displayed on the opposing board 23 so that the display resolution of the opposing board 23 becomes higher than the resolution of the linear image sensor 21. Thereby, the defect | deletion of the edge part of the image of such a reading result can be decreased.

[Fourth Embodiment]
When the original paper is thin, the predetermined pattern displayed on the counter plate 23 is included as a show-through in the portion corresponding to the image to be read in the image read by the linear image sensor 21. There is.

  For this reason, the scanner unit control unit 201 determines whether or not a portion corresponding to the image to be read out of the read result image includes a predetermined pattern stored in the memory of the scanner unit control unit 201. Then, when it is determined that the image is included, image processing for erasing the included predetermined pattern is executed.

  In this way, even if the predetermined pattern is included as a show-through when the edge of the read image can be specified by displaying the image of the predetermined pattern on the opposing plate 23, the predetermined pattern is included. Can be erased. For this reason, the quality of the read image can be maintained.

[Fifth Embodiment]
In order to prevent a predetermined pattern from being included as a show-through like the problem shown in the fourth embodiment, the following may be performed. The scanner control unit 201 displays an image of a predetermined pattern on the counter plate 23 at the timing before and after the leading edge and the trailing edge of the document pass the reading position 114, and at the other timing, the scanner unit control unit 201 displays a monochromatic image ( For example, a white only image or a black only image) is displayed. Then, the scanner control unit 201 identifies the end of the image after cropping by detecting the four corners of the image after cropping based on the scanned image corresponding to the leading and trailing edges of the document.

  As a result, cropping can be reliably performed, and when reading a portion other than the leading edge and the trailing edge of the document that is considered to mainly include an image to be read, an image of a predetermined pattern is not displayed on the counter plate 23. Since a monochromatic image is displayed, show-through can be prevented.

[Sixth Embodiment]
In order to prevent a predetermined pattern from being included as a show-through like the problem shown in the fourth embodiment, the following may be performed. Based on the document size information detected by each sensor 202 or the document size information set by the user, the scanner control unit 201 detects the size of the document to be read.

  The scanner control unit 201 displays an image of a predetermined pattern on the counter plate 23 at a timing before and after the leading edge of the document passes the reading position 114, and at other times, a single color image (for example, white color) is displayed on the counter plate 23. Only images, or only black images).

  Based on the read image corresponding to the front end of the document, the scanner control unit 201 determines the coordinate information and angle information of one corner of the front end of the read image (how much tilted with respect to the main scanning direction or the sub scanning direction). Is detected). The scanner unit control unit 201 specifies the edge of the cropped image based on the coordinate information and angle information of one corner and the size of the document.

  As a result, cropping can be reliably performed, and when reading a portion other than the leading edge of the document that is considered to contain mainly the image to be read, the monochrome image is not displayed on the counter plate 23 without displaying a predetermined pattern image. Since it is displayed, show-through can be prevented.

[Seventh Embodiment]
In order to prevent a predetermined pattern from being included as a show-through like the problem shown in the fourth embodiment, the following may be performed. Based on the document size information detected by each sensor 202 or the document size information set by the user, the scanner control unit 201 detects the size of the document to be read.

  The scanner unit control unit 201 displays an image of a predetermined pattern on the counter plate 23 at the timing before and after the leading edge of the document passes the reading position 114. The scanner control unit 201 detects a portion corresponding to one side of the leading edge of the document based on the image of the reading result corresponding to the leading edge of the document.

  Based on the detected one side and the size of the document, the scanner unit control unit 201 displays an image of a predetermined pattern on the counter plate 23 corresponding to the vicinity of the edge of the document in accordance with the movement of the document. A monochromatic image (for example, an image of white only or an image of black only) is displayed at the position of the counter plate 23 corresponding to a portion different from the vicinity of the end. For example, when the size of the document is A4, an image of a predetermined pattern is displayed at the position of the counter plate 23 corresponding to the vicinity of the edge of the document of A4, and a monochrome image is displayed at other positions. When the size of the document is A3, an image of a predetermined pattern is displayed at the position of the facing plate 23 corresponding to the vicinity of the edge of the document of A3, and a monochrome image is displayed at other positions.

  The scanner control unit 201 identifies the edge of the image corresponding to the document by detecting the boundary between the image corresponding to the document and the image of the predetermined pattern from the read result image.

  As a result, cropping can be performed reliably, and a single-color image is not displayed on the opposing plate 23 on a portion other than the edge portion of the document that is considered to contain mainly the image to be read. Since it is displayed, show-through can be prevented.

  In the above-described embodiment, an example in which an image of a predetermined pattern is displayed on the counter plate 23 when reading an image of the surface of an object such as a document has been described. However, when an image of the back surface of the object is read. In addition, the same contents can be applied to the counter plate 24.

[Summary]
(1) As described above, as illustrated in FIG. 3, the scanner unit 20 of the image forming apparatus 100 reads the target image indicated on the target object (for example, a paper document) ( For example, a reading device 15 including a linear image sensor 21 and a reading unit 22 including a linear image sensor, and a counter plate (for example, a counter plate) provided to face the reading unit and capable of displaying a counter image on the side of the reading unit. 23, 24) and a scanner unit control unit 201.

  As shown in FIGS. 8 to 17, when the target image of the target object between the reading unit and the counter plate is read by the reading unit, the scanner unit control unit 201 changes the relative position with respect to the target image. The counter image of the predetermined pattern is displayed on the counter plate, and the edge of the read image is detected by detecting the boundary between the read image corresponding to the target image and the background image corresponding to the counter image in the image read by the reading unit. Identify.

  As a result, the end of the read image can be specified regardless of the characteristics of the target image indicated in the read target.

  (2) As shown in FIGS. 8 and 12, the predetermined pattern includes a region having a color different from the adjacent region that is parallel to any side of the rectangular opposing image.

  (3) As shown in FIG. 8 and FIG. 15, the predetermined pattern includes an area that is not parallel to any side of the rectangular opposing image and has a different color from the adjacent area.

  (4) As shown in FIGS. 8, 12, and 15, the different color regions are regions having different RGB ratios or densities.

  (5) As shown in the third embodiment, the predetermined pattern has a resolution higher than the resolution of the reading unit.

  (6) As shown in the fourth embodiment, the scanner unit control unit 201 executes image processing for erasing a transparent image when the scanned image includes the transparent image of the opposite image.

  (7) As shown in FIG. 5 to FIG. 7, when the target image is read by the reading unit while conveying the object, the scanner unit control unit 201 reads the predetermined pattern and target of the counter image displayed on the counter plate. The predetermined pattern is moved so that the position relative to the image does not change.

  (8) As shown in the second embodiment, the scanner unit control unit 201 displays on the counter plate when the object is not detected even when the tip of the object reaches the reading unit. The predetermined pattern of the opposite image is changed.

  (9) As shown in the fifth embodiment, the scanner unit control unit 201 opposes a counter-pattern image of a predetermined pattern when the front and rear end portions near the front end and rear end of the object are read by the reading unit. When the front and rear end portions are not read by the reading unit, a single color image is displayed on the counter plate, and the four corners of the read image are detected based on the read images corresponding to the front end and the rear end of the target image. To identify the end of the read image.

  (10) As shown in the sixth embodiment, the scanner unit 20 further includes each sensor 202 that detects the size of the object. The scanner control unit 201 displays an opposing image of a predetermined pattern on the opposing plate when the front end portion near one corner of the front end of the object is read by the reading unit, and when the front end portion is not read by the reading unit. A monochrome image is displayed on the counter plate, one corner of the read image is detected based on the read image corresponding to the tip of the target image, and the read image is detected based on the detected one corner and the size detected by the detection unit. Identify the edge.

  (11) As described in the seventh embodiment, the scanner unit 20 further includes each sensor 202 that detects the size of the object. The scanner control unit 201 detects one side of the read image based on the read image corresponding to the tip of the target image, and based on the detected one side and the size detected by the detection unit, the end of the target object A counter image of a predetermined pattern is displayed at the position of the counter plate corresponding to the vicinity of the object in accordance with the movement of the object, and the monochromatic image is targeted at the position of the counter plate corresponding to a part different from the vicinity of the end of the object The edge of the read image is specified by displaying it according to the movement of the object and detecting the boundary between the read image and the background image.

[Modification]
(1) In the above-described embodiments, the invention has been described as the image forming apparatus 100 including the scanner unit 20 and the image reading apparatus exemplified by the scanner unit 20. However, the present invention is not limited to this, and any other device including an image reading device may be used. For example, a scanner device, a printer with a scanner, or a facsimile may be used. There may be.

  (2) In the above-described embodiment, the opposing plates 23 and 24 are configured by reflective display elements used as electronic paper. However, the present invention is not limited to this, and the opposing plates 23 and 24 may be configured by other display devices, for example, may be configured by a reflective liquid crystal display device, or may be a color display. The display device may be a monochrome display device.

  (3) In the embodiment described above, when the target image is read by the reading unit while conveying the target object, when the target image of the target object between the reading unit and the counter plate is read by the reading unit, By moving the predetermined pattern so that the relative position between the predetermined pattern of the counter image displayed on the counter plate and the target image does not change, the predetermined pattern is prevented from changing the relative position with respect to the target image. The counter image was displayed on the counter plate.

  However, the present invention is not limited to this, and the original image is fixed on a platen like a flatbed scanner, and the reading unit including the linear image sensor is moved with respect to the original while the target image indicated on the original is displayed. In the case of reading, the above-described embodiment can be applied. In this case, the counter plate is wider than the original. An opposing image having a predetermined pattern is displayed on the opposing plate so that the relative position with respect to the target image shown on the original does not change. That is, since the document is fixed, the predetermined pattern of the opposing image is fixed and displayed so as not to move. Specifically, the entire image having a predetermined pattern as shown in FIGS. 8, 12 and 15 is displayed on a counter plate wider than the size of the document.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 15 Reading apparatus, 20 Scanner part, 21 Linear image sensor, 22 Reading part, 23, 24 Opposite plate, 25 Exposure lamp, 26A, 26B, 26C Mirror, 30 Printer part, 100 Image forming apparatus, 101 Paper feed tray, 102 Pick Roller, 103 Separation roller, 104 Registration roller, 105, 106, 107 Reading roller, 108 Paper discharge roller, 109 Paper discharge tray, 110 Control unit, 111 Separation sensor, 112 Registration sensor, 113 Sensor before reading, 114, 115 Reading position , 120 storage unit, 130 operation unit, 140 display unit, 160 communication unit, 190 operation panel, 201 scanner unit control unit, 202 sensors, 203 motor drive unit, 900 private network.

Claims (12)

A reading unit that reads a target image shown on a target to be read;
A counter plate provided facing the reading unit and capable of displaying a counter image on the side of the reading unit;
A control unit,
The controller is
When the target image of the object between the reading unit and the counter plate is read by the reading unit, the counter image having a predetermined pattern whose relative position with respect to the target image does not change is displayed on the counter plate. Display
An image reading apparatus that identifies an end of the read image by detecting a boundary between a read image corresponding to the target image and a background image corresponding to the counter image in an image read by the reading unit.   The image reading apparatus according to claim 1, wherein the predetermined pattern includes a region having a different color from an adjacent region that is parallel to any side of the rectangular opposing image.   The image reading apparatus according to claim 1, wherein the predetermined pattern includes an area that is not parallel to any side of the rectangular opposing image and has a different color from an adjacent area.   4. The image reading apparatus according to claim 2, wherein the different color regions are regions having different RGB ratios or densities. 5.   The image reading apparatus according to claim 1, wherein the predetermined pattern has a resolution equal to or higher than a resolution of the reading unit.   The image reading apparatus according to claim 1, wherein the control unit executes image processing for deleting the transparent image when the transparent image of the counter image is included in the read image.   When the target image is read by the reading unit while conveying the target object, the control unit changes a relative position between the predetermined pattern of the counter image displayed on the counter plate and the target image. The image reading apparatus according to claim 1, wherein the predetermined pattern is moved so as not to occur.   The said control part changes the said predetermined pattern of the said opposing image currently displayed on the said opposing board, when the said object is not detected even when the front-end | tip of the said object reaches | attains the said reading part. Item 8. The image reading device according to Item 7. The controller is
When the front and rear end portions in the vicinity of the front end and the rear end of the object are read by the reading unit, the counter image of the predetermined pattern is displayed on the counter plate, and the front and rear end portions are not read by the reading unit. Sometimes a single color image is displayed on the counter plate,
The image reading apparatus according to claim 7, wherein an end portion of the read image is specified by detecting four corners of the read image based on the read image corresponding to a front end and a rear end of the target image. A detection unit for detecting the size of the object;
The controller is
When the tip portion near one corner of the tip of the object is read by the reading unit, the counter image of the predetermined pattern is displayed on the counter plate, and when the tip portion is not read by the reading unit Display a monochromatic image on the counter plate,
Based on the read image corresponding to the tip of the target image, one corner of the tip of the read image is detected,
The image reading apparatus according to claim 7, wherein an end portion of the read image is specified based on one detected corner and the size detected by the detection unit. A detection unit for detecting the size of the object;
The controller is
Based on the read image corresponding to the tip of the target image, one side of the read image is detected,
Based on the detected one side and the size detected by the detection unit, the counter image of the predetermined pattern is moved to the target object at the position of the counter plate corresponding to the vicinity of the end of the target object. And display a monochromatic image in accordance with the movement of the object at the position of the counter plate corresponding to a part different from the vicinity of the end of the object,
The image reading apparatus according to claim 7, wherein an end portion of the read image is specified by detecting a boundary between the read image and the background image.   An image forming apparatus comprising the image reading apparatus according to claim 1.

Images