JP2006013882A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology of enhancing the productivity of outputs from an image reading apparatus for carrying out double side simultaneous reading, which reads both images formed on a front side and a rear side of an original as color images. <P>SOLUTION: An original reading apparatus reads images formed on the front and rear sides of the original respectively as color images by carrying of the original once. The amount of front side image data read by a CCD image sensor 78 and rear side image data read by a CIS 50 is halved to the original data amount by halving the resolution of both the image data in the subscanning direction. The front side image data and the rear side image data whose data amount is halved are stored in a memory 106 having been originally provided with a storage capacity for storing the rear side image data of one picture. Thereafter while the CCD image sensor 78 and the CIS 50 are used to read a carried succeeding original as color images, the front side image data and the rear side image data of the preceding original stored in the memory 106 are externally transferred. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus that reads an image of an original, and more particularly, to an image reading apparatus that reads an image formed on both front and back sides of an original as a color image.

  Conventionally, image reading devices (automatic double-sided reading devices) that automatically read image information on both sides of a document without user intervention are widely used as reading devices such as copying machines and facsimiles, and scanners for computer input. Yes. As these automatic double-sided reading devices, a method of reading a document by reversing the front and back with a document reversing unit is most widely adopted. That is, when inputting image information on both the front and back sides by this conventional method, after reading one side by the document reading unit, the discharged document is turned upside down and conveyed again to the document reading unit. The other side is read in the department.

  However, this automatic double-sided scanning by reversing the front and back requires that the original is once discharged and then reversed and transported again to the original reading unit. End up. The document reversing unit requires a complicated mechanism for reversing the front and back of the document. A document jam (JAM) occurrence rate at the document reversing unit is higher than that of other conveying units, and the reliability is improved. It was requested. Furthermore, when designing an automatic double-sided scanning device in a narrow space, it is necessary to invert the document and to rapidly invert the document with a small diameter due to the necessity of aligning the number of pages of the document when discharging. May occur. As a result, it has been difficult to convey a document made of predetermined thick paper having a large basis weight.

  Therefore, a technique has been studied in which two image sensors are provided on both front and back sides of a document path for transporting a document, and both sides of the document are automatically read by a single document transport without reversing the document. For example, see Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-356867 (5th page, FIG. 1)

  As described above, in the automatic double-sided scanning apparatus using the front / back reversal, it is necessary to turn the document upside down by using the reversing path for reversing the document as described above. Productivity decreases. On the other hand, as in the above-mentioned Patent Document 1, when both sides are read at the same time with one conveyance (no reversal) of the document, the reading productivity does not deteriorate due to the reversal path.

  However, even when the simultaneous reading of both sides by one conveyance of the original is realized, it is difficult to increase the productivity unless the transfer speed to the subsequent stage is improved. For example, when an automatic double-sided scanning device is used in a copying machine, the document transport speed during scanning is the same as the transport speed of the paper (recording paper) on which the image is formed in the copying machine. However, even when both sides of a document are read simultaneously without inversion, the productivity of document reading cannot be improved. Even if double-sided simultaneous scanning is performed, if the image transfer speed to the subsequent stage is not improved, the reading productivity is equivalent to, for example, that transporting a document at half the recording paper transport speed of the copying machine main body. turn into.

  Recently, a color image reading apparatus that reads an image formed on a document as a full-color image has been put into practical use. However, when the images formed on both sides of the document in the above-described double-sided simultaneous reading are read as color images. However, since the data amount of the front surface image data and the back surface image data is several times the data amount of the monochrome image, it has been difficult to improve the manuscript reading productivity.

  The present invention has been made to solve such a technical problem, and an object of the present invention is to perform both-sided simultaneous reading capable of reading both images formed on the front and back sides of a document as color images. It is to improve the productivity of output from the reading device.

  For this purpose, the image reading apparatus to which the present invention is applied reads the image on the first side of the original from one side of the conveyed original as a color image by the first reading means, and the other side of the original. The image on the second side of the original is read as a color image by the second reading means, and the color image data on the first side of the original read by the first reading means is the amount of data in the color image data on the first side Is converted by the first data amount conversion means to the first image data that is less than half of the color image data of the second side of the original read by the second reading means in the color image data of the second side The first image data and the second data amount converted by the second data amount conversion means into the second image data that is less than half of the data amount, and converted by the first data amount conversion means. The second image data converted by the conversion unit is stored in the storage unit, and the first document stored in the storage unit is read while the next document is being read by the first reading unit and the second reading unit. The image data and the second image data are transferred by the transfer means.

  Here, the first data amount conversion means reduces the resolution in the sub-scanning direction in the color image data of the first surface read by the first reading means to half or less, and the second data amount conversion means The resolution in the sub-scanning direction in the color image data of the second surface read by the second reading means can be reduced to half or less. In addition, the first data amount conversion unit sets the gradation in the color image data of the first surface read by the first reading unit to 4 gradations or less, and the second data amount conversion unit includes the second data amount conversion unit. The gradation in the color image data of the second surface read by the reading unit can be reduced to 4 gradations or less.

  From another point of view, the image reading apparatus to which the present invention is applied reads the color image data on the front side of the document and the color image data on the back side of the document before the reading of the color image data on the front side is completed. Is read by the reading means, the resolution of the color image data on the front surface and the color image data on the back surface read by the reading means is reduced and converted to the image data on the front surface and the image data on the back surface by the resolution conversion means, and the resolution conversion means The front side image data and the back side image data whose resolution has been converted are merged by the merging unit, the front side image data and the back side image data merged by the merging unit are stored in the storage unit, and the reading unit scans the next original document. An image of the merged surface stored in the storage means while the reading is taking place Over data and back side image data transferred by the transfer means.

  Here, the resolution conversion unit can halve the resolution in the sub-scanning direction in the color image data on the front surface and the color image data on the back surface read by the reading unit. In this case, the merging means can perform merging so that the color image data on the front surface and the color image data on the back surface converted by the data amount conversion means are alternately arranged in the sub-scanning direction.

  Further, from another viewpoint, the image reading apparatus to which the present invention is applied reads the color image data on the front side of the document, and the color image data on the back side of the document before the reading of the color image data on the front side is completed. Is read by the reading means, and the number of gradations of the color image data on the front surface and the color image data on the back surface read by the reading means is reduced and converted into the image data on the front surface and the image data on the back surface by the gradation converting means. The front side image data and the back side image data whose number of gradations has been reduced by the tone conversion unit are rearranged by the rearrangement unit, and the front side image data and the rear side image data rearranged by the rearrangement unit are stored in the storage unit. The rearrangement stored in the storage means while the next original is being read by the reading means. The image data and back side image data of the surface to transfer the transfer unit.

  Here, the gradation converting means converts the color image data of the front surface and the color image data of the back surface composed of RGB data of 256 gradations of each color read by the reading means into YMCK data of 4 gradations or less for each color. Can be a feature. In this case, the rearranging means rearranges the color image data on the front surface and the color image data on the back surface, the number of gradations of which is reduced, so that YMCK data having 4 gradations or less of each color are adjacent to each other. it can.

  According to the present invention, it is possible to improve the productivity of output from a reading device in simultaneous double-sided reading in which both images formed on the front and back sides of a document can be read as color images.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below in detail with reference to the accompanying drawings.
—Embodiment 1—
FIG. 1 is a diagram showing an image reading apparatus to which the present embodiment is applied. The image reading device includes a document feeding device 10 that sequentially conveys documents from a stacked document bundle, a scanner device 70 that reads an image by scanning, a processing device 80 that processes a read image signal, and a processing device 80. The image processing apparatus 100 is roughly divided into image processing apparatuses that perform image processing on output.

  The document feeder 10 includes a document tray 11 on which a bundle of documents composed of a plurality of documents is stacked, and a tray lifter 12 that raises and lowers the document tray 11 as an example of components of a paper feed unit. Further, a nudger roll 13 that conveys the original on the original tray 11 raised by the tray lifter 12, a feed roll 14 that conveys the original conveyed by the nudger roll 13 further downstream, and an original supplied by the nudger roll 13. Are provided with a retard roll 15. In the first transport path 31 where the original is first transported, a takeaway roll 16 that transports the originals that are being fed one by one to the downstream roll, transports the original to the further downstream roll, and creates a loop. The pre-registration roll 17 to be performed, the rotation is resumed at the timing after stopping once, the registration roll 18 for supplying the original while adjusting the registration to the original reading unit, the platen roll 19 for assisting the conveyance of the original being read, An out-roll 20 is provided for conveying the read original further downstream. The first transport path 31 includes a baffle 41 that rotates about a fulcrum according to the loop state of the document being transported. Further, a CIS (Contact Image Sensor) 50, which is a second sensor in the present embodiment, is provided between the platen roll 19 and the out-roll 20.

  A second transport path 32 and a third transport path 33 are provided on the downstream side of the out-roll 20, a transport path switching gate 42 for switching between these transport paths, a discharge tray 40 for stacking documents that have been read, and a discharge tray A first discharge roll 21 that discharges the original document 40 is provided. In addition, an inverter roll 22 and an inverter pinch roll 23 that are provided in the fourth transport path 34 and the fourth transport path 34 for switching back the document that has passed through the third transport path 33 and actually switch back the document, The document switched back by the fourth transport path 34 is again guided to the first transport path 31 including the pre-registration roll 17 and the like, and the document switched back by the fourth transport path 34 is discharged to the discharge tray 40. The transport paths of the second discharge roll 24, the fifth transport path 35, and the sixth transport path 36 that are provided in the sixth transport path 36 and the sixth transport path 36 and transport the inverted document to the first discharge roll 21. An exit switching gate 43 for switching is provided.

  The nudger roll 13 is lifted up and held at the retracted position during standby, and descends to the nip position (original conveyance position) during conveyance of the document to convey the uppermost document on the document tray 11. The nudger roll 13 and the feed roll 14 convey a document by connecting a feed clutch (not shown). The pre-registration roll 17 makes a loop by abutting the leading end of the document against the stopped registration roll 18. In the registration roll 18, when the loop is created, the leading edge of the document bitten by the registration roll 18 is returned to the nip position. When this loop is formed, the baffle 41 opens around the fulcrum and functions so as not to interfere with the document loop. Further, the take away roll 16 and the pre-registration roll 17 hold a loop during reading. By this loop formation, the read timing can be adjusted, and the skew associated with the document conveyance at the time of reading can be suppressed, and the alignment adjustment function can be enhanced. The stopped registration roll 18 starts rotating in accordance with the start timing of reading, and is pressed against the second platen glass 72B (described later) by the platen roll 19 to read the image data from the lower surface direction.

  The conveyance path switching gate 42 switches so that the document passing through the out-roll 20 is guided to the second conveyance path 32 and discharged to the discharge tray 40 at the end of reading one-sided document and at the same time when reading both-side documents simultaneously. It is done. On the other hand, the transport path switching gate 42 is switched so as to guide the document to the third transport path 33 in order to invert the document when the double-sided document is sequentially read. The inverter pinch roll 23 is retracted with the feed clutch (not shown) turned off during sequential reading of the double-sided document to open the nip, and guides the document to the inverter path (fourth conveyance path 34). Thereafter, the inverter pinch roll 23 is nipped, the original to be inverted by the inverter roll 22 is guided to the pre-registration roll 17, and the original to be reversed is conveyed to the second discharge roll 24 in the sixth conveyance path 36.

  The scanner device 70 is configured to be capable of placing the document feeder 10 described above, supports the document feeder 10 by an apparatus frame 71, and reads an image of the document conveyed by the document feeder 10. Yes. The scanner device 70 includes a first platen glass 72A for placing a document to be read in a stationary state on a device frame 71 forming a casing, and a light for reading a document being conveyed by the document feeder 10. A second platen glass 72 </ b> B is formed to form the opening.

  The scanner device 70 is stationary under the second platen glass 72B and scans the entire first platen glass 72A to read an image, and the light obtained from the full rate carriage 73 is image-coupled. A half-rate carriage 75 is provided to provide a portion. The full-rate carriage 73 includes an illumination lamp 74 that is a white light source and irradiates light on the original, and a first mirror 76A that receives reflected light obtained from the original. Further, the half-rate carriage 75 is provided with a second mirror 76B and a third mirror 76C that provide the light obtained from the first mirror 76A to the imaging unit. Further, the scanner device 70 includes an imaging lens 77 that optically reduces the optical image obtained from the third mirror 76C, and a CCD (Charge Coupled Device) that photoelectrically converts the optical image formed by the imaging lens 77. ) An image sensor 78 and a drive substrate 79 having a CCD image sensor 78 are provided, and an image signal obtained by the CCD image sensor 78 is sent to the processing device 80 through the drive substrate 79. In the present embodiment, a so-called color sensor that reads an image of a document as a color image is used as the CCD image sensor 78.

  Here, first, when reading an image of a document placed on the first platen glass 72A, the full rate carriage 73 and the half rate carriage 75 move in the scanning direction (arrow direction) at a ratio of 2: 1. . At this time, the light of the illumination lamp 74 of the full rate carriage 73 is irradiated on the surface to be read of the document, and the reflected light from the document is reflected in the order of the first mirror 76A, the second mirror 76B, and the third mirror 76C. Then, it is guided to the imaging lens 77. The light guided to the imaging lens 77 forms an image on the light receiving surface of the CCD image sensor 78. The CCD image sensor 78 is a one-dimensional sensor and processes one line at the same time. When reading of one line in this line direction (main scanning direction of scanning) is completed, the full-rate carriage 73 is moved in a direction (sub-scanning direction) orthogonal to the main scanning direction to read the next line of the document. By executing this over the entire document size, reading of one page of the document is completed.

  On the other hand, the second platen glass 72B is constituted by a transparent glass plate having a long plate-like structure, for example. A document conveyed by the document feeder 10 passes over the second platen glass 72B. At this time, the full-rate carriage 73 and the half-rate carriage 75 are stopped at the solid line positions shown in FIG. First, the reflected light of the first line of the document that has passed through the platen roll 19 of the document feeder 10 is imaged by the imaging lens 77 via the first mirror 76A, the second mirror 76B, and the third mirror 76C. An image is read by the CCD image sensor 78 which is the first sensor in the present embodiment. That is, after one line in the main scanning direction is simultaneously processed by the CCD image sensor 78 which is a one-dimensional sensor, the next line in the main scanning direction of the original conveyed by the original feeding device 10 is read. After the leading edge of the document reaches the reading position of the second platen glass 72B, the document passes through the reading position of the second platen glass 72B, whereby reading of one page is completed in the sub-scanning direction.

  In the present embodiment, the full-rate carriage 73 and the half-rate carriage 75 are stopped, and the first platen glass 72B is used to read the first surface of the document by the CCD image sensor 78. It is possible to read the second surface of the document by the CIS 50 as the second sensor (in the sense that it is not coincident but about the same document transport time). That is, by using the CCD image sensor 78 as the first sensor and the CIS 50 as the second sensor, it is possible to simultaneously read the images on both the front and back sides of the original by conveying the original to the conveyance path once. Yes. The CCD image sensor 78 and the CIS 50 constitute a reading unit.

  FIG. 2 is a diagram for explaining a reading structure using the CIS 50. As shown in FIG. 2, the CIS 50 is provided between the platen roll 19 and the out roll 20. One side (first side) of the original is pressed against the second platen glass 72B, and the image on the first side is read by the CCD image sensor 78 as a color image. On the other hand, in the CIS 50, an image on one side (second side) is read from the other side facing through a conveyance path for conveying a document. The CIS 50 is a glass 51, an LED (Light Emitting Diode) array 52 that irradiates the second surface of the document through the glass 51, and a lens array that collects the reflected light from the LED array 52. A SELFOC lens (registered trademark) 53 and a line sensor 54 which is an image sensor for reading light condensed by the SELFOC lens 53 are provided. As the line sensor 54, a CCD, a CMOS sensor, a contact sensor, or the like can be used, and an image with an actual width (for example, A4 longitudinal width 297 mm) can be read. In the CIS 50, since the image is captured using the SELFOC lens 53 and the line sensor 54 without using the reduction optical system, the structure can be simplified, the housing can be downsized, and the power consumption can be reduced. Can be reduced. Here, in the present embodiment, a combination of LED light sources of three colors R (red), G (green), and B (blue) or a white LED light source is used as the LED array 52, and RGB three colors are used as the line sensor 54. A set of sensors for three rows is used, and the second side of the document can also be read as a color image.

  Further, when the image is read by the CIS 50, a control member 55 extending from the casing of the CIS 50 and an abutting member 60 for abutting the sheet pressed by the control member 55 are provided on the conveyance path constituting the reading unit. A guide member 61 is provided on the downstream side of the abutting member 60. The control member 55 and the abutting member 60 are positioned in the conveyance path from the front surface to the rear surface of the document feeder 10 in a direction orthogonal to the document conveyance path (that is, from the front surface to the rear surface of the document feeder device 10). Correspondingly provided.

  Further, since the CIS 50 employs the SELFOC lens 53 as an optical imaging lens, the depth of focus (field of view) is as shallow as about ± 0.3 mm, which is about 1 compared with the case where the scanner device 70 is used. The depth is less than / 13. When reading with the CIS 50, it is required to set the reading position of the document within a predetermined narrow range. Therefore, in the present embodiment, the control member 55 is provided, and the document is pressed against the abutting member 60 by the control member 55 and conveyed, so that the posture of the document between the platen roll 19 and the out-roll 20 can be stabilized. It was configured to be controllable. The “paper movement B” indicated by the solid line arrow in FIG. 2 indicates the paper movement when the control member 55 is not present, and the “paper movement A” indicated by the two-dot chain line arrow is the control member 55. This shows the movement of the paper when the is provided. In the “paper movement A”, it can be understood that the document is pressed against the abutting member 60 and conveyed. That is, by reading the document conveyed by the control member 55 while being pressed against the abutting member 60, the sweetness of the focus when the CIS 50 having a shallow depth of field is used is improved.

Next, the processing device 80 shown in FIG. 1 will be described.
FIG. 3 is a block diagram for explaining the processing device 80. The processing device 80 to which this embodiment is applied is large and controls the signal processing unit 81 that processes image information obtained from the sensors (CCD image sensor 78 and CIS 50), the document feeder 10 and the scanner device 70. And a control unit 90. The signal processing unit 81 processes an analog signal for each output from the CCD image sensor 78 that reads the front surface (first surface) of the document and the CIS 50 (line sensor 54) that reads the back surface (second surface). AFE (Analog Front End) 82, ADC (Analog to Digital Converter) 83 that converts an analog signal into a digital signal, and two digital processing units 84 that perform various processing such as shading correction and offset correction on the digital signal are provided. Therefore, digital processing is separately performed on the read images on the front surface (first surface) and the back surface (second surface). The digital signal processed by the digital processing unit 84 is subjected to processing such as resolution conversion by an image processing apparatus (IPS) 100, and for example, an IOT (Image Output Terminal) such as a printer, or a host such as a personal computer (PC). Output to the system.

  On the other hand, the control unit 90 includes an image reading control 91 that controls the entire document feeding device 10 and the scanner device 70, including various double-sided scanning control and single-sided scanning control, a CCD / image sensor 78 and a CCD / CIS 50 that controls the CIS 50. A CIS control 92, a lamp control 93 for controlling the LED array 52 of the CIS 50 and the illumination lamp 74 of the full rate carriage 73 in accordance with the reading timing, a motor on / off of the scanner device 70, etc., and a full rate carriage 73 and a half rate carriage 75 A scanning control 94 for controlling the scanning operation of the document, a motor control in the document feeder 10, a transport mechanism control 95 for controlling various roll operations, feed clutch operations, gate switching operations, and the like. There. From these various controls, control signals are output to the document feeder 10 and the scanner device 70, and these operations can be controlled based on the control signals. The image reading control 91 sets a reading mode based on a control signal from the host system, a sensor output detected in the automatic selection reading function, a selection from the user, and the like, and controls the document feeder 10 and the scanner device 70. I have control. As the reading mode, a double-sided simultaneous reading mode with one pass (no reversal), a double-sided reading mode with a reverse pass, and a single-sided reading mode with one pass can be considered.

Next, functions and operations of the image processing apparatus 100 will be described.
FIG. 4 is a block diagram illustrating a configuration of the image processing apparatus 100 to which the present exemplary embodiment is applied. The image processing apparatus 100 is obtained from a CCD image sensor 78 as a first reading unit, and is a surface (first surface) formed of a digitized high resolution (for example, 600 SPI (Spot Per Inch) × 600 SPI) full color image. The first color image processing unit 101 serving as the first data amount converting means or resolution converting means for processing the image data, and the CIS 50 serving as the second reading means, and the digitized high resolution (for example, 600 SPI × 600 SPI). ) A second color image processing unit 102 for processing image data of the back surface (second surface) formed of a full color image, and an image data storage unit 103 for storing input color image data.

  The image data storage unit 103 is provided in the programmable logic array 104 that performs serial conversion or the like of input color image data (parallel data), and is input from the first color image processing unit 101. The first side color image data and the second side color image data input from the second color image processing unit 102 are merged and output as a merging unit 105 and the data output from the multiplexer 105 are stored. And a memory controller 107 as a transfer means for controlling the memory 106. In the image data storage unit 103, the first color image processing unit 101 and the second color image processing unit 102 provide 24 bits (3 colors × 8 bits) composed of 8 bits for each color of RGB (256 gradations, multivalue). Color image data is input. The memory controller 107 controls the memory 106 so that the input three color (RGB) color image data is stored for each color.

  In this image reading apparatus, as described above, the first side and the second side of the document can be read as full-color images. Further, in this image reading apparatus, normally, one original can be read with a resolution of 600 SPI × 600 SPI and RGB each color 8 bits (256). For this reason, the memory 106 has a memory capacity capable of storing color image data with a resolution of 600 SPI × 600 SPI, three colors, and 256 gradations.

Now, a double-sided color original reading process using this image reading apparatus will be described in detail. FIG. 5 is a flowchart showing the flow of double-sided reading when a double-sided color original, resolution 600 SPI × 600 SPI, 8-bit gradation (256 gradations), and productivity is 100%. Here, one side of the document is read using the maximum document transport capability of the document feeder 10 and the document transport by the document feeder 10 is not stopped (without waiting) when outputting image data to the outside. The state in which reading is sequentially executed is “productivity 100%”.
The flow of this process will be described with reference to FIG. 5. First, the document is fed by the document feeder 10, and the CCD image sensor 78 reads the first surface of the document and the CIS 50 reads the second surface of the same document. Is performed (step 101). Among these, the color image data (surface image data) of the first surface of the document read by the CCD image sensor 78 is subjected to the first color image processing after being subjected to shading correction and gap correction by the signal processing unit 81. The unit 101 performs color conversion processing, gradation conversion processing (TRC), automatic exposure adjustment (AE), and the like, and performs image quality adjustment such as background removal, gamut conversion, and gamma correction (step 102). (Step 103).

  On the other hand, the color image data (back side image data) of the second side of the document read by the CIS 50 in step 101 is subjected to shading correction, gap correction, and the like by the signal processing unit 81, and then the second color image processing unit. In 102, color conversion processing, gradation conversion processing (TRC), automatic exposure adjustment (AE), and the like are performed to perform image quality adjustment such as background removal, gamut conversion, and gamma correction (step 104). Are output as 24-bit color image data. The 24-bit color image data consisting of 8 bits for each color of RGB passes through the multiplexer 105 and is stored in the memory 106 by the memory controller 107 (step 105). Then, after the output of the front surface image data in step 103 is completed, a memory read signal is output to the memory controller 107 (step 106), and the back surface image data stored in the memory 106 is converted into the first color image processing unit 101. Are output to an external device such as a printer or a PC (step 107). Then, it is determined whether or not there is a document to be read next (step 108). If there is a next document, the process returns to step 101 to continue the process. If there is no next document, the process is performed. Exit.

Next, another processing example will be described.
FIG. 6 is a flowchart showing the flow of double-sided scanning when a double-sided color original, resolution 300 SPI × 600 SPI, 8-bit gradation (256 gradations), and productivity is 200%. Note that the resolution of 300 SPI × 600 SPI means that the resolution in the sub-scanning direction is 300 SPI and the resolution in the main scanning direction is 600 SPI. “Productivity 200%” means a state in which both sides of a document are simultaneously read using the normal (100%) document transport capability of the document feeder 10 and sequentially read. In this state, continuous reading is possible without stopping (without waiting). The above-mentioned “simultaneous” is not limited to the case where the time coincides completely. For example, as in the present embodiment, when there is a time overlap between reading the front image data of the document and reading the back image data, reading of the back image data is started before the reading of the front image data is completed. In this case, it is possible to include a case where the image data on both the front and back sides of the document is read by one transport without inverting the document.

The flow of processing will be described with reference to FIG. 6. First, a document is conveyed by the document feeder 10, and the first surface of the document is read by the CCD image sensor 78 and the second surface of the same document is read by the CIS 50. Performed (step 201). Of these, the surface image data read by the CCD image sensor 78 is subjected to shading correction, gap correction, and the like by the signal processing unit 81, and then subjected to predetermined image processing in the first color image processing unit 101. At the same time, resolution conversion is executed through a filter circuit or the like, and the input 600 SPI × 600 SPI surface image data is converted into 300 SPI × 600 SPI RGB data or La ^* b ^* data (step 202). On the other hand, the back surface image data read by the CIS 50 in step 201 is subjected to shading correction, gap correction, and the like by the signal processing unit 81, and then subjected to predetermined image processing in the second color image processing unit 102. Then, resolution conversion is executed through a filter circuit or the like, and the input 600 SPI × 600 SPI surface image data is converted into RGB data or La ^* b ^* data of 300 SPI × 600 SPI (step 203). Note that, by reducing the resolution in the sub-scanning direction from 600 SPI to 300 SPI, the data amount of the front surface image data and the back surface image data after the resolution conversion is relative to the data amount of the front surface image data and the back surface image data before the resolution conversion. Each is half.

  Thereafter, the front surface image data whose resolution has been converted in step 202 and the back surface image data whose resolution has been converted in step 203 are input to the multiplexer 105, and the front surface data and the back surface image data are merged by the multiplexer 105 and merged table. The back image data is stored in the memory 106 by the memory controller 107 (step 204). Here, the resolution-converted front surface image data and back surface image data are both half the data amount of 300 SPI × 600 SPI with respect to the image data of 600 SPI × 600 SPI. The image data for one sheet can be stored in the memory 106 provided. A specific method for merging the front surface image data and the back surface image data will be described later.

  Then, it is determined whether there is a document to be read next (step 205). If there is no next original, a memory read signal is output to the memory controller 107 (step 206), and the merged front and back image data stored in the memory 106 is subjected to the first color image processing. The data is output to an external device such as a printer or a PC via the unit 101 (step 207), and the process is terminated.

On the other hand, if the next original exists in step 205, a memory read signal is output to the memory controller 107 (step 208), and the merged front and back image data stored in the memory 106 is the first. The data is output to an external device via the color image processing unit 101 (step 209). Further, while the front and back image data is output, the next document is conveyed by the document feeder 10, the first surface of the document is read by the CCD image sensor 78, and the second surface of the same document is read by the CIS 50. Reading is performed (step 210). Of these, the surface image data read by the CCD image sensor 78 is subjected to shading correction, gap correction, and the like by the signal processing unit 81, and then subjected to predetermined image processing in the first color image processing unit 101. At the same time, resolution conversion is executed through a filter circuit or the like, and the input 600 SPI × 600 SPI surface image data is converted into 300 SPI × 600 SPI RGB data or La ^* b ^* data (step 211). On the other hand, the back surface image data read by the CIS 50 in step 201 is subjected to shading correction, gap correction, and the like by the signal processing unit 81, and then subjected to predetermined image processing in the second color image processing unit 102. Then, resolution conversion is performed through a filter circuit or the like, and the input 600 SPI × 600 SPI surface image data is converted into RGB data or La ^* b ^* data of 300 SPI × 600 SPI (step 212).

  Thereafter, the front surface image data whose resolution has been converted in step 211 and the back surface image data whose resolution has been converted in step 212 are input to the multiplexer 105, and the front surface data and the back surface image data are merged by the multiplexer 105 and merged table. The back image data is stored in the memory 106 by the memory controller 107 (step 213). Then, the process returns to step 205.

Next, the merging of the front surface image data and the back surface image data in step 204 will be described.
FIG. 7A shows the relationship between a page sync signal (PS signal), a line sync signal (LS signal), and 600 SPI data when an image of a document is read at a resolution of 600 SPI × 600 SPI (hereinafter simply referred to as 600 SPI). . In the case of 600 SPI, 600 SPI color image data is input according to the LS signal shown in the figure.
On the other hand, FIG. 7B shows the relationship between a PS signal, an LS signal, and 300 SPI data when reading an image of a document with a resolution of 300 SPI × 600 SPI (hereinafter simply referred to as 300 SPI). FIG. 7B shows both the front surface image data read by the CCD image sensor 78 and converted in resolution, and the back surface image data read by the CIS 50 and converted in resolution. In the case of 300 SPI, the front image data and the back image data are input simultaneously.

  Therefore, in the present embodiment, as shown in FIG. 7C, the front image data and the back image data are shifted by 1 LS in the above-described 300 SPI, and the PS signal is also synchronized, so that the front image data of 300 SPI is synchronized. And backside image data are merged. Thereby, the front surface image data and the back surface image data can be merged in real time and stored in the memory 106. As a method of shifting the front surface image data and the back surface image data by 1 LS, for example, a method of shifting the PS signal generation at the time of image reading by 1 LS or an odd number of LS on the front and back, and the PS signal at the time of image reading are In this case, a method of shifting by 1 LS by temporarily storing the back surface image data or the front surface image data in the line memory, etc. can be considered.

As described above in detail, according to the present embodiment, when both the images formed on both sides of the original by reading the original are read as color images, the front image data and the back image data are sub-scanned. By reducing the directional resolution to 300 SPI, which is half of the original resolution 600 SPI, the data amount of the front surface image data and the back surface image data is reduced to half of the original data amount. As a result, the front image data and the back image data, that is, the image data for two sheets can be collectively stored in the memory 106 originally provided for storing the one back image data. Then, while reading the next document to be conveyed as a color image using the CCD image sensor 78 and the CIS 50, the front image data and the back image data of the document before being stored in the memory 106 are transferred to the outside. I tried to do it. As a result, productivity in simultaneous reading on both sides can be improved, and 200% productivity can be secured.
In addition, before storing the 300 SPI front image data and back image data in the memory 106, the 300 SPI front image data and back image data are merged using the multiplexer 105, so that the front image Data and backside image data can be stored in the memory 106.
Further, in general resolution conversion, the main resolution and the sub-scan are often set to the same resolution (300 SPI). In the present embodiment, even in the case of the same resolution in the main and sub scans, the effective data in the LS signal is only halved, and is the same as described above.

-Embodiment 2-
The present embodiment is substantially the same as the first embodiment, but the number of gradations is reduced instead of lowering the resolution of the front surface image data and the rear surface image data read by the CCD image sensor 78 or the CIS 50. Therefore, the amount of data is reduced. In addition, in this Embodiment, about the thing similar to Embodiment 1, the same code | symbol as Embodiment 1 is attached | subjected and the detailed description is abbreviate | omitted.
FIG. 8 is a block diagram illustrating a configuration of the image processing apparatus 100 to which the present exemplary embodiment is applied. The basic configuration of the image processing apparatus 100 is the same as that described in the first embodiment, but is output from the first color image processing unit 101 in place of the multiplexer 105 provided in the first embodiment. A first rearrangement unit 108 for rearranging the 24-bit color image data, and a second rearrangement unit 109 for rearranging the 24-bit color image data output from the second color image processing unit 102. Is different. The first sorting unit 108 and the second sorting unit 109 constitute a sorting unit.

Also in the image reading apparatus according to the present embodiment, when the productivity is 100%, the duplex color original reading process is performed according to the procedure described with reference to FIG.
Here, FIG. 9 is a flowchart showing the flow of double-sided reading processing when a double-sided color original, resolution 600 SPI × 600 SPI, 1-bit gradation (2 gradations), and productivity is 200%.
The flow of processing will be described with reference to FIG. 9. First, a document is conveyed by the document feeder 10, and the first surface of the document is read by the CCD image sensor 78 and the second surface of the same document is read by the CIS 50. Performed (step 301). Among these, the surface image data read by the CCD image sensor 78 is subjected to shading correction, gap correction, and the like by the signal processing unit 81, and then a predetermined image is processed by the first color image processing unit 101 as gradation converting means. The surface image data that has been processed and input in RGB 8-bit gradation is converted into binarized YMCK image data (step 302). On the other hand, the back side image data read by the CIS 50 in step 301 is subjected to predetermined image processing in the second color image processing unit 102 as gradation converting means after the signal processing unit 81 performs shading correction and gap correction. And the back side image data input with RGB 8-bit gradation is converted into binarized YMCK image data (step 303).

  Thereafter, the first rearrangement unit 108 is input with the front surface image data subjected to gradation conversion in step 302 and the second rearrangement unit 109 is input with the rear surface image data subjected to gradation conversion in step 303, The front image data is rearranged by the first rearrangement unit 108 and the rear image data is rearranged by the second rearrangement unit 109 and stored in the memory 106 by the memory controller 107 (step 304). Here, the data amounts of the front surface image data and the back surface image data subjected to the gradation conversion are both one-third or less of the data amount of the 8-bit gradation image data before the gradation conversion. Image data for two front and back surfaces can be stored in a memory 106 provided for storing image data for one sheet. A specific method for rearranging the front surface image data and the back surface image data subjected to gradation conversion will be described later.

  Then, it is determined whether there is a document to be read next (step 305). If there is no next original, a memory read signal is output to the memory controller 107 (step 306), and the tone-converted front and back image data stored in the memory 106 is the first color. The image data is output to an external device such as a printer or a PC via the image processing unit 101 (step 307), and the process is terminated.

  On the other hand, if there is a next original in step 305, a memory read signal is output to the memory controller 107 (step 308), and the tone-converted front and back image data stored in the memory 106 is the first. 1 is output to an external apparatus via the color image processing unit 101 (step 309). Further, while the front and back image data is output, the next document is conveyed by the document feeder 10, the first surface of the document is read by the CCD image sensor 78, and the second surface of the same document is read by the CIS 50. Reading is performed (step 310). Among these, the surface image data read by the CCD image sensor 78 is subjected to shading correction, gap correction, and the like by the signal processing unit 81, and then a predetermined image is processed by the first color image processing unit 101 as gradation converting means. The surface image data that has been processed and is input with RGB 8-bit gradation is converted into binarized YMCK image data (step 311). On the other hand, the back side image data read by the CIS 50 in step 301 is subjected to predetermined image processing in the second color image processing unit 102 as gradation converting means after the signal processing unit 81 performs shading correction and gap correction. And the back side image data input with RGB 8-bit gradation is converted into binary (1 bit) YMCK image data (step 312).

  Thereafter, the first rearrangement unit 108 is input with the front surface image data subjected to gradation conversion in step 302 and the second rearrangement unit 109 is input with the rear surface image data subjected to gradation conversion in step 303, The front image data is rearranged by the first rearrangement unit 108, and the rear image data is rearranged by the second rearrangement unit 109, and stored in the memory 106 by the memory controller 107 (step 313). Then, the process returns to step 305.

Next, the rearrangement of the front surface image data and the back surface image data in step 304 will be specifically described.
FIG. 10A shows the formats of the front surface image data output from the first color image processing unit 101 and the back surface image data output from the second color image processing unit 102. As described above, in the normal 100% productivity mode, the front surface image data and the back surface image data are output in a total of 24 bits of 8 bits for each RGB color, and the upper 8 bits (23 to 16) of the data bus are R (Red: R7 to R0), middle 8 bits (15 to 08) are G (green: G7 to G0), and lower 8 bits (07 to 00) are B (blue: B7 to B0). On the other hand, in the 200% productivity mode in this embodiment, the front image data and the back image data are output in a total of 4 bits, that is, 1 bit for each color of YMCK. M, 15 bits are C, and 11 bits are K. That is, only 4 bits are used for a 24-bit bus, and the other 20 bits are unused.
Therefore, in this embodiment, the YMCK surface image data that has been binarized (1 bit) and input via a 24-bit bus is rearranged by the first rearrangement unit 108, as shown in FIG. Thus, the data is collected into 8-bit data. On the other hand, similarly, the back side image data of YMCK that has been binarized (1 bit) and input via a 24-bit bus is rearranged by the second rearrangement unit 109, and as shown in FIG. Combined into bit data. Thereby, the data amounts of the front surface image data and the back surface image data are each one third of the original data amount, and the front surface image data and the back surface image data can be stored in the memory 106.

  As described above in detail, in the present embodiment, the front surface image data and the back surface image data of RGB 8-bit gradation are converted into YMCK 1-bit gradation, and the converted surface image data output in 24 bits respectively. The rear image data and rear image data are rearranged and gathered to form 8-bit data, respectively, and the data amounts of the front image data and the rear image data are each one third of the original data amount. As a result, the front image data and the back image data, that is, the image data for two sheets can be collectively stored in the memory 106 originally provided for storing the one back image data. Then, while reading the next document to be conveyed as a color image using the CCD image sensor 78 and the CIS 50, the front image data and the back image data of the document before being stored in the memory 106 are transferred to the outside. I tried to do it. As a result, productivity in simultaneous reading on both sides can be improved, and 200% productivity can be secured.

  In this embodiment, the front image data and the back image data of RGB 8-bit gradation are converted into YMCK 1-bit gradation. However, the present invention is not limited to this. For example, as shown in FIG. , YMCK 2-bit gradation can also be converted. In this case, since the first rearrangement unit 108 and the second rearrangement unit 109 can combine the data into 8-bit data as shown in FIG. % Productivity can be secured.

  In the first and second embodiments, the CCD image sensor 78 is used as the first reading means for reading the front surface of the document, and the CIS 50 is used as the second reading means for reading the back surface of the document. For example, both the reading of the front and back surfaces may be performed by the CCD image sensor, or both may be performed by the CIS.

  In the first and second embodiments, the amount of front surface image data is reduced to less than half of the original data amount, and the amount of back surface image data is also reduced to less than half of the original data amount. In addition, the back side image data, that is, the image data for two sheets can be stored together in the memory 106 originally provided for storing the back side image data. However, the present invention is not limited to this. Absent. For example, the data amount of the front surface image data may be reduced to 70% of the original data amount, and the data amount of the back surface image data may be reduced to 30% of the original data amount. In other words, if the image data for two sheets of the front image data and the back image data can be reduced to such an extent that they can be stored in the memory 106, the reduction ratio distribution and data for the front image data and the back image data can be reduced. As a method for reducing the amount, it is possible to adopt a method as appropriate.

It is the figure which showed the image reading apparatus with which this Embodiment is applied. It is a figure for demonstrating the reading structure using CIS. It is a block diagram for demonstrating a processing apparatus. 1 is a block diagram illustrating a configuration of an image processing apparatus according to Embodiment 1. FIG. 10 is a flowchart showing the flow of double-sided reading processing when a duplex color original, resolution of 600 SPI × 600 SPI, 8-bit gradation (256 gradations), and productivity is set to 100%. 10 is a flowchart showing a flow of double-sided reading processing when a duplex color original, resolution of 300 SPI × 600 SPI, 8-bit gradation (256 gradations), and productivity is set to 200%. (a)-(c) is a figure for demonstrating the merge of the surface image data and back surface image data which carried out resolution conversion. 6 is a block diagram illustrating a configuration of an image processing apparatus according to Embodiment 2. FIG. 6 is a flowchart showing a flow of double-sided reading processing when a duplex color original, resolution 600 SPI × 600 SPI, 1-bit gradation (2 gradations), and productivity is 200%. (a)-(c) is a figure for demonstrating rearrangement of the surface image data and back surface image data by which gradation conversion was carried out.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Document feeder, 50 ... CIS, 52 ... LED array, 53 ... Selfoc lens, 54 ... Line sensor, 70 ... Scanner device, 73 ... Full-rate carriage, 74 ... Illumination lamp, 75 ... Half-rate carriage, 77 ... Connection Image lens, 78 ... CCD image sensor, 79 ... Drive substrate, 80 ... Processing device, 81 ... Signal processing unit, 82 ... AFE (Analog Front End), 83 ... ADC (Analog Digital Converter), 84 ... Digital processing unit, DESCRIPTION OF SYMBOLS 90 ... Control part, 91 ... Image reading control, 92 ... CCD / CIS control, 93 ... Lamp control, 94 ... Scan control, 95 ... Conveyance mechanism control, 100 ... Image processing apparatus, 101 ... First color image processing part, 102: second color image processing unit, 103: image data storage unit, 104: programmer Le Logic Array (FPGA), 105 ... multiplexer, 106 ... memory, 107 ... memory controller, 108 ... first rearrangement section, 109 ... second rearrangement section

Claims (9)

First reading means for reading, as a color image, an image on the first surface of the original from one side of the original being conveyed;
Second reading means for reading an image of the second surface of the original as a color image from the other side of the original;
First data for converting the color image data of the first side of the original read by the first reading unit into first image data that is less than half of the data amount of the color image data of the first side. A quantity conversion means;
Second data for converting the color image data on the second side of the original read by the second reading means into second image data that is less than half of the data amount of the color image data on the second side. A quantity conversion means;
Storage means for storing the first image data converted by the first data amount conversion means and the second image data converted by the second data amount conversion means;
Transfer means for transferring the first image data and the second image data stored in the storage means while the next original is being read by the first reading means and the second reading means. And an image reading apparatus. The first data amount conversion unit reduces the resolution in the sub-scanning direction in the color image data of the first surface read by the first reading unit to half or less,
2. The second data amount conversion unit reduces the resolution in the sub-scanning direction in the color image data of the second surface read by the second reading unit to half or less. Image reading device. The first data amount conversion means sets the gradation in the color image data of the first surface read by the first reading means to 4 gradations or less,
2. The image according to claim 1, wherein the second data amount conversion unit sets the gradation in the color image data of the second surface read by the second reading unit to 4 gradations or less. Reading device. Reading means for reading the color image data of the front side of the document and reading the color image data of the back side of the document before the reading of the color image data of the front side is completed;
Resolution conversion means for reducing the resolution of the color image data on the front surface and the color image data on the back surface read by the reading means and converting them into image data on the front surface and image data on the back surface;
Merging means for merging the image data of the front surface and the image data of the back surface, the resolution of which has been converted by the resolution converting means;
Storage means for storing the image data of the front surface and the image data of the back surface merged by the merging means;
An image reading apparatus comprising: transfer means for transferring the merged image data on the front surface and image data on the back surface stored in the storage means while the next original is being read by the reading means.   5. The image reading apparatus according to claim 4, wherein the resolution conversion unit halves the resolution in the sub-scanning direction of the color image data of the front surface and the color image data of the back surface read by the reading unit. .   6. The image reading according to claim 5, wherein the merging unit performs merging so that the color image data on the front surface and the color image data on the back surface converted by the data amount conversion unit are alternately arranged in the sub-scanning direction. apparatus. Reading means for reading the color image data of the front side of the document and reading the color image data of the back side of the document before the reading of the color image data of the front side is completed;
Gradation conversion means for reducing the number of gradations of the color image data on the front surface and the color image data on the back surface read by the reading means and converting them into image data on the front surface and image data on the back surface;
Rearrangement means for rearranging the image data of the front surface and the image data of the back surface, the number of gradations of which is reduced by the gradation conversion means;
Storage means for storing the image data of the front surface and the image data of the back surface rearranged by the rearranging means;
An image reading apparatus comprising: transfer means for transferring the rearranged image data on the front side and the back side stored in the storage means while the next original is being read by the reading means.   The gradation converting means converts the color image data of the front surface and the color image data of the back surface composed of 256 gradation RGB data read by the reading means into YMCK data of 4 colors or less for each color. The image reading apparatus according to claim 7.   The rearrangement unit rearranges the color image data on the front surface and the color image data on the back surface in which the number of gradations is reduced so that the YMCK data having 4 gradations or less of each color are adjacent to each other. 8. The image reading device according to 8.

Images