JP2005151001A - Image scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of memory required for setting image parameters in order to perform image processing of image data using the image data on one page of a document when opposite sides of the document are read out. <P>SOLUTION: The image scanner comprises a CCD image sensor 78 for reading out one side of a document being carried, and a CIS 50 for reading out the other side of the document. Even if double-sided reading and monochrome reading are selected, the document is carried while being reversed and the images on the opposite sides of the document are read out sequentially when an entire surface ground removing mode for removing the ground of the document using image parameters based on the image data on one page of the document is selected. When a forward end ground removing mode for removing the ground of the document using image parameters for the image data at the forward end part of the document is selected, images on both the sides of the document are read out at a time without reversing the document. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus that reads an image on a document, and more particularly, to an image reading apparatus that can read images on both sides.

  Conventionally, an image reading device (automatic double-sided reading device) that automatically reads image information on both sides of a document without user intervention is used as a reading device such as a copying machine or a facsimile, or a scanner for computer input. . 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. When inputting image information with the front and back reversed, after reading the image on the front side with a specific original reading unit, the original is turned over and conveyed to the specific original reading unit again, and the image on the back side is read. .

  However, in this double-sided automatic reading by reversing the front and back, it is necessary to reverse the document once and then reverse it and transport it again to the document reading unit. End up. Therefore, a so-called double-sided simultaneous reading technique in which two image reading units are provided on both the front and back sides of a document path for conveying a document and the front and back surfaces of the document are automatically read by one document conveyance is being studied. Therefore, for example, by providing image sensors on both the front and back sides of the document path for transporting the document, it is possible to automatically read both sides of the document in one document transport without inverting the document. Technology exists (for example, refer to Patent Document 1).

JP 2000-244718 A (page 2-4, FIG. 1)

  By the way, in the image reading apparatus, not only a white background document that is generally used but also a document having various background densities such as a newspaper or colored paper is to be read. Such a document other than a white background has a high background density. Therefore, if the image data read by the document reading unit is reproduced as it is, the background comes out and the image quality deteriorates. Therefore, from the image data obtained by pre-scanning the document with the document reader (pre-scan), detecting the background of the document, setting image parameters, and then reading the document with the document reader (main scan) The background is removed using image parameters.

  However, in the double-sided automatic reading device described in Patent Document 1 described above, when the background removal is to be performed by such a method, the surface image data obtained by reading the front side of the document and the back side of the document are read. Both of the obtained back surface image data must be temporarily stored in the memory. For this reason, the capacity of the memory required for storing the image data on both the front and back surfaces increases, and the cost increases. Such a problem is not limited to the removal of the background of the document, but can occur in the same way when image processing is performed using image parameters obtained based on image data for one page of the document.

The present invention has been made to solve such a technical problem, and an object of the present invention is to perform image processing on image data using image data for one page of the document in double-sided reading of the document. This is to reduce the amount of memory required when setting image parameters to be performed.
Another object of the present invention is to perform high-speed image reading when image parameters for performing image processing on image data using image data for one page of the original are not set in double-sided reading of the original.

  For this purpose, an image reading apparatus to which the present invention is applied includes a paper feed unit that feeds a document, a transport path through which a document fed from the paper feed unit is transported, and one side of the transport path. A first sensor that reads an image on one side of a document from a second sensor, a second sensor that reads an image on one side of a document from the other side facing the one side through a conveyance path, and an image by the first sensor A reverse conveyance path for reversing and conveying the read original to the conveyance path, and setting image parameters for performing image processing on image data using image data for one page of the original In addition, one side of the document conveyed on the conveyance path is read by the first sensor, the document is reversed and conveyed to the conveyance path via the reverse conveyance path, and the other side of the document is read by the first sensor. 1st duplex mode and 1 page of original When image parameters for performing image processing on image data using image data corresponding to the first image are not set, images on both the front and back sides of the document are transported to the transport path once by the first sensor and the second sensor. And a second double-sided reading mode read by the sensor.

  Here, the image processing apparatus may further include a memory that stores image data read by the first sensor or the second sensor. This memory can be characterized by having a capacity corresponding to image data of less than two pages of the document. In the first double-sided reading mode, image data for one page of a single-sided original read by the first sensor is stored in a memory, and image processing parameters are set based on the image data for one page of a single-sided original. The image data read from the memory is subjected to image processing using the image processing parameters and output, and the image data for one page of the other side of the original document that has been transported in reverse and read by the first sensor is stored in the memory. And image processing parameters are set based on the image data for one page of the document on the other side, and the image data read from the memory is subjected to image processing using the image processing parameters and output. can do. Further, in the second double-sided reading mode, image data for one page of a single-sided document read by the first sensor is output and for one page of another single-sided document read by the second sensor. The image data is output after being stored in the memory.

From another point of view, an image reading apparatus to which the present invention is applied includes a paper feed unit that feeds a document, a transport path through which a document fed from the paper feed unit is transported, and a transport path A first sensor that reads an image on one side of a document from one side, a second sensor that reads an image on one side of a document from the other side facing the one side via a conveyance path, and a first sensor The reversing conveyance path for reversing the front and back of the document from which the image has been read and conveying it to the conveyance path, and the pre-processing of the processing performed when reading the image data of the document or after reading the image data of the document In the case of performing, the first sensor reads one side of the document conveyed on the conveyance path, then reversely conveys the document to the conveyance path via the reversal conveyance path, and the other side of the document is moved to the first side. And a reading control unit for reading by the sensor. .
Here, the preprocessing can be characterized in that it is a parameter setting for removing the background of the document from the image data.

  Further, from another viewpoint, the image reading apparatus to which the present invention is applied reads the image data on the first side of the document with the first reading unit, and reads the image data on the second side of the document with the second reading. The second surface image data read by the second reading means is stored in the storage means, and after the first surface image data read by the first reading means is output, the storage means An image for outputting image data of the second surface stored in the output means by the output means and performing image processing on the image data of the first face based on the image data of the first face read by the first reading means When setting the parameters, the image data of the first surface is transferred to the storage means by the transfer means.

  Here, the transfer means may read the image data of the first surface stored in the storage means when performing image processing based on the obtained image parameter. Further, when setting the image parameter, only the first reading unit can be used for reading the document.

  According to the present invention, in duplex scanning of a document, when setting image parameters for performing image processing on this image data using image data for one page of the document, it is possible to reduce a necessary memory amount. .

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.
FIG. 1 is a diagram showing an image reading apparatus to which the present embodiment is applied. This image reading apparatus is roughly divided into a document feeding device 10 that sequentially conveys documents from a stacked document bundle, a scanner device 70 that reads an image by scanning, and a processing device 80 that processes a read image signal.

  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 for rolling them one by one. In the first conveyance path 31 where the original is first conveyed, a take-away roll 16 that conveys the originals that are being fed one by one to the downstream roll, conveys the original further to the downstream roll, and forms 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, between the platen roll 19 and the out roll 20, a CIS (Contact Image Sensor) 50, which is the second reading means in the present embodiment, is provided.

  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. Further, 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, and the fourth transport. A document that is switched back by the path 34 is again guided to the first transport path 31 including the pre-registration roll 17 and the like, and the document that is 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 disturb 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. In accordance with the read start timing, the stopped registration roll 18 starts rotating, is pressed against the second platen glass 72B (described later) by the platen roll 19, and is imaged from the lower surface direction by the CCD image sensor (described later). Is read.

  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 as the second reading unit is configured to be able to place the document feeding device 10 described above, and is supported by the device frame 71 and conveyed by the document feeding device 10. The original image is being scanned. 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 stands still below the second platen glass 72B, scans the entire first platen glass 72A, reads the image, and reads the image obtained from the full-rate carriage 73 as an image coupling unit. A half-rate carriage 75 is provided. The full-rate carriage 73 includes an illumination lamp 74 that 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 serves as an imaging lens 77 that optically reduces the optical image obtained from the third mirror 76C, and a first sensor that photoelectrically converts the optical image formed by the imaging lens 77. A CCD (Charge Coupled Device) image sensor 78 and a drive substrate 79 including the CCD image sensor 78 are provided, and an image signal obtained by the CCD image sensor 78 is sent to the processing device 80 via the drive substrate 79.

  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. The second side of the document can be read by the CIS 50 as the second reading means (in the sense that it is not coincident but the same as when the same document is conveyed). That is, by using the CCD image sensor 78 serving as the first reading unit and the CIS 50 serving as the second reading unit, the images on both the front and back sides of the document can be simultaneously read by transporting the document to the transport path once. It is possible.

  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, front side) of the document is pressed against the second platen glass 72B, and the image on the first side is read by the CCD image sensor 78. On the other hand, in the CIS 50, an image on one side (second side, back side) is read from the other side facing through a conveyance path for conveying a document. The CIS 50 includes a glass 51, an LED (Light Emitting Diode) 52 that irradiates light onto the second surface of the document through the glass 51, and a SELFOC lens that is a lens array that collects reflected light from the LED 52. 53, and a line sensor 54 as a second sensor for reading the light collected by the selfoc lens 53. 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. Similar to the reading of the image on the first surface, one line in the main scanning direction is simultaneously processed by the one-dimensional line sensor 54, and then the next line in the main scanning direction in the conveyed document is read. In this way, one page of the back side of the conveyed document is read in the sub-scanning direction.

  In addition, 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 that abuts the original pressed by the control member 55 are provided in 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 the 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. Configured to be controllable. The two-dot chain line arrow in FIG. 2 shows the movement of the document when the control member 55 is provided. It can be understood that the document to be conveyed is conveyed while being pressed against the abutting member 60. 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 as a reading control unit. The processing device 80 to which the present embodiment is applied is large and includes a signal processing unit 81 that processes image information obtained from sensors (CCD image sensor 78 and line sensor 54), a document feeder 10 and a scanner device 70. And a control unit 90 for controlling. The signal processing unit 81 performs predetermined image processing on outputs from the CCD image sensor 78 that reads the front surface (first surface) of the document and the line sensor 54 of the CIS 50 that reads the back surface (second surface) of the document. ing. The signal processing unit 81 includes an AFE (Analog Front End) 82 that processes an analog signal with respect to an output from the line sensor 54, and an ADC (Analog to Digital Converter) 83 that converts the analog signal into a digital signal. Yes. However, these functions may be configured to be processed inside the CIS 50. The signal processing unit 81 includes two systems of image processing circuits that perform various processing such as shading correction and offset correction on the digital signal, and performs image processing on the image data on the front surface (first surface). A first image processing circuit 100 for performing image processing and a second image processing circuit 200 for performing image processing on image data on the back surface (second surface) are provided. The output from these image processing circuits is output to an IOT (Image Output Terminal) such as a printer or a host system such as a personal computer (PC).

  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. The CIS control 92, the lamp control 93 for controlling the LED 52 of the CIS 50 and the illumination lamp 74 of the full-rate carriage 73 in accordance with the reading timing, and the scanning of the full-rate carriage 73 and the half-rate carriage 75 by turning on / off the motor in the scanner device 70. A scan control 94 for controlling the operation, 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 are provided.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, the double-sided simultaneous reading mode by one pass (without reversal), the reverse double-sided reading mode by reversing pass, the single-sided reading mode by one pass, etc. can be considered.

Next, the function and operation of each image processing circuit (first image processing circuit 100 and second image processing circuit 200) will be described.
FIG. 4 is a block diagram illustrating the configuration of the signal processing unit 81 in further detail. The first image processing circuit 100 includes a first CPU 101 that performs overall control, an AFE / ADC 102 that performs sample hold, offset adjustment, A / D conversion, and the like on the surface image data output from the CCD image sensor 78. The first selector (first SEL) 103 is provided as output means for selecting and outputting the image data. Furthermore, an A integrated circuit (ASIC-A) 110 that performs shading correction and inter-line correction (RGB misregistration interpolation), and an B integrated circuit (ASIC-B) that performs MTF filter, reduction / enlargement processing, binarization processing, etc. ) 130.

  On the other hand, the second image processing circuit 200 selects the second CPU 201 that performs overall control, the C integrated circuit (ASIC-C) 210 that performs various image processing on the back image data obtained from the CIS 50, and the front and back image data. A second selector (second SEL) 202 serving as a transfer means for outputting and temporarily holding (storing) the image data that has undergone image processing, and outputting it to the first selector 103 in accordance with a predetermined output timing The memory 203 is provided as storage means. In this embodiment, the memory 203 has a capacity corresponding to image data for one page (and less than two pages) of the maximum size document that can be read by the image reading apparatus.

FIG. 5 is a block diagram showing the configuration of the A integrated circuit (ASIC-A) 110. The A integrated circuit 110 includes a shading correction unit 111 for correcting shading data in the CCD image sensor 78, a GAP correction unit 112 for correcting the positions of the RGB three-color line sensors, and a black line correction unit 113 for correcting black lines. An ENL 115 that corrects the input gradation, a color space conversion unit 116 that converts BGR → L ^* a ^* b ^* , and a background detection unit 117 that detects the background of the read document and generates image parameters for background removal. Yes. Further, a timing generation unit (Timing generation) 119 that generates a driving clock for the CCD image sensor 78 and the AFE / ADC 102, and a CPU interface (CPU IF) 120 that communicates with the first CPU 101 are provided.

FIG. 6 is a block diagram showing the configuration of the B integrated circuit (ASIC-B) 130. The B integrated circuit 130 includes a digital filter unit 131 that performs MTF correction and smoothing, a sub-scanning reduction unit 132 that performs a reduction process with respect to the sub-scanning direction that is the document conveyance direction, and a CCD that is orthogonal to the document conveyance direction. A main scanning enlargement / reduction unit 133 that performs enlargement / reduction processing in the main scanning direction which is the scanning direction of the image sensor 78, a background removal unit 135 that removes the background of the read document based on the background detection result by the background detection unit 117, L ^* a ^* b ^* → YMCK is provided with a lookup table (LUT) 136 for color space conversion. In addition, a CPU interface (CPU IF) 140 that performs communication with the first CPU 101 is provided.

FIG. 7 is a block diagram showing the configuration of the C integrated circuit (ASIC-C) 210. The C integrated circuit 210 performs shading correction based on shading data stored in the shading memory 221 and a multiplex (MPX) circuit 211 that performs synthesis (O / E synthesis) of 2-channel output signals composed of Odd / Even. Shading correction unit 212, L ^* conversion unit (LUT) 213 for correcting input gradation, sub-scanning / reduction unit 214 for performing reduction processing in the sub-scanning direction, and main-scanning / reduction unit for performing enlargement / reduction processing in the main-scanning direction 215, a filter unit 216 that performs MTF correction and smoothing, a background removal unit 217 that performs background removal based on a background detection result by the background detection unit 222, a look-up table (LUT) 218 that performs output tone correction, and binarization An error diffusion processing unit (Packing error diffusion) 219 is provided. A CPU interface 223 that communicates with the second CPU 201 is also provided.

  Here, in the present embodiment, when an image is read by conveying the document by the document feeder 10, the scanner device 70 (CCD image sensor 78) is used for the document conveyed to the platen roll 19 through the second platen glass 72B. And can be read using the CIS 50 provided in the document feeder 10. However, as described above, the depth of focus differs between reading by the CCD image sensor 78 using the mechanism of the scanner device 70 and reading using the SELFOC lens 53 of the CIS 50, resulting in a difference in resolution characteristics. End up. In particular, when a color image such as a photograph or a high-accuracy monochrome image is read, color matching or density matching becomes difficult when both are read, and the image quality obtained by reading both is different. Therefore, in the present embodiment, a plurality of reading modes are prepared, and an optimum reading mode can be selected based on the setting state of the apparatus, the type of document, the user's selection, and the like.

  FIG. 8 is a flowchart showing an example of processing executed by the image reading control 91 shown in FIG. In the image reading control 91, first, it is determined which function of copy, facsimile (Fax), or scanner (Scan) has been selected (step 101). This determination is recognized by the user's selection using a control panel (not shown) provided on the scanner device 70, for example.

  Next, the image reading control 91 determines whether the conveyed document is a double-sided document or a single-sided document (step 102). This determination is made by, for example, the selection of the user using a control panel (not shown) provided on the scanner device 70, or the first conveyance path 31 before image reading when the automatic selection reading function is working, for example. It can be recognized by sensors (not shown) provided on both sides of the upper conveyance path. In addition, a request from the host system, a selection from a user via a network, and the like can be considered. If it is determined in step 102 that the original is a single-sided original, single-sided reading is performed by one pass (one-time original conveyance pass without using a reverse pass) (step 103). In this one-pass single-sided reading, either the reading by the CCD image sensor 78 or the reading by the CIS 50 may be selected. However, in order to realize higher-quality image reading, the reading by the CCD image sensor 78 is selected. It is preferable to do. In this case, by placing the original part on one side upward and placing the first page of the original on top, the original is conveyed and read sequentially from the first page.

  If it is determined in step 102 that the document is not a single-sided document, that is, if it is determined to be a double-sided document, it is next determined whether the conveyed document is a color document or a monochrome document (step 104). ). This determination is recognized by the user's selection using a control panel (not shown) provided on the scanner device 70, for example. Even for a color document, the user may desire to read in black and white, and the user can designate the color document as a monochrome document. Here, when performing color reading, double-sided reading is performed by two passes (reverse pass) (step 105). That is, the front and back surfaces of the document are both read by the CCD image sensor 78 without being read by the CIS 50. As a result, both the front and back sides of a color document can be read on both sides with high image quality using a reading means having a deep focal depth.

  On the other hand, when color reading is not performed in step 104, that is, when black and white reading is performed, it is next determined whether a request for reading a black and white document is high image quality or high productivity (step 106). ). This determination is recognized by the user's selection using a control panel (not shown) provided on the scanner device 70, for example. Here, when high image quality is required, double-sided reading by two passes (reverse pass) is performed as in the case of performing double-sided reading of a color original (step 105). That is, the front and back surfaces of the document are both read by the CCD image sensor 78 without being read by the CIS 50. As a result, both the front and back sides of a black and white document can be read on both sides with high image quality using a reading means having a deep focal depth.

  Further, when high image quality is not required in step 106, that is, when high productivity is required, double-sided simultaneous reading by one pass without using the reverse pass is performed (step 107). That is, the front surface of the original is read by the CCD image sensor 78, and the back side of the original is read by the CIS 50 in the same conveyance path during the reading conveyance path. This eliminates the need to transport the document twice to the same reading unit, improves the document reading speed, and simplifies the transport path, thereby preventing document transport troubles such as document jamming (JAM). Can be suppressed. As described above, “simultaneous reading” does not necessarily mean that they coincide with each other in time, but means that both sides of a document are read at approximately the same time in one pass.

Here, FIGS. 9A to 9D show an example of a user interface (UI) displayed on a control panel (not shown) in each step described above. FIG. 9A shows a screen for accepting a function selection by the user in step 101. FIG. 9B shows a screen for accepting selection of a double-sided document / single-sided document by the user in step 102. The screen of FIG. 9B is displayed when “Copy” is selected from “Copy”, “Fax”, and “Scan” shown in FIG. 9A. Further, FIG. 9C shows a screen for accepting color / monochrome selection by the user in step 104. Further, FIG. 9D shows a screen for accepting selection of high image quality / high productivity by the user in step 106. The screen of FIG. 9D is displayed when “Monochrome” is selected from “Color” and “Monochrome” shown in FIG. 9C.
Thus, in this embodiment, high image quality or high productivity can be selected for all of copying, facsimile, and scanning.

Next, a document transport method in each document reading mode will be described with reference to FIGS.
FIGS. 10A and 10B are views showing a document pass in the single-sided reading mode by one pass shown in step 103 of FIG. 8 and the double-sided simultaneous reading mode by one pass shown in step 107. FIG. As shown in FIG. 10A, the documents placed on the document tray 11 are sequentially supplied to the first transport path 31 by the nudger roll 13, the feed roll 14, the retard roll 15, and the takeaway roll 16. . As shown in FIG. 10B, the supplied document is moved to the second conveyance path 32 by the conveyance path switching gate 42 via the reading section of the platen roll 19 and the reading section of the CIS 50, and the discharge tray 40. Are discharged sequentially. Here, in the case of single-sided reading, reading is performed at the position of the platen roll 19 from below using the CCD image sensor 78 of the scanner device 70 shown in FIG. In the case of simultaneous reading on both sides, the front side of the original is read using the CCD image sensor 78 of the scanner device 70, and the back side of the original is read using the CIS 50 during the same conveyance. As a result, it is possible to read both sides of the document by one document pass.

  FIGS. 11A to 11D are views showing document paths in the two-sided reading mode with two paths shown in step 105 of FIG. As shown in FIG. 11A, the originals placed on the original tray 11 are sequentially supplied to the first transport path 31, and using the CCD image sensor 78 of the scanner device 70 shown in FIG. The surface of the document is read from below at the position. Then, the transfer path switching gate 42 moves to the fourth transfer path 34 via the third transfer path 33. The document completely passing through the third conveyance path 33 is switched back by the inverter roll 22 and the inverter pinch roll 23 and supplied to the fifth conveyance path 35 as shown in FIG.

  The document supplied to the fifth conveyance path 35 is again supplied to the first conveyance path 31. Then, as shown in FIG. 11C, the document is read from below by the CCD image sensor 78 of the scanner device 70. At this time, the document is in an inverted state from the case shown in FIG. 11A, and the back side, not the front side, of the document is read. The document whose back side has been read is in a state in which the front and back sides are reversed. If the document is discharged to the discharge tray 40 as it is, the page order of the loaded document after reading will be out of order. Therefore, as shown in FIG. 11C, the document whose back side has been read is moved to the fourth transport path 34 via the third transport path 33 using the transport path switching gate 42. The document supplied to the fourth transport path 34 and completely passing through the exit switching gate 43 is discharged to the discharge tray 40 via the sixth transport path 36 by the exit switching gate 43 as shown in FIG. . This makes it possible to align the page order of the original after reading in the double-sided reading mode for sequentially reading the images on both sides of the original.

  By the way, in the image reading apparatus according to the present embodiment, the image is read by the CCD image sensor 78 using the background detection unit 117 provided in the A integrated circuit 110 and the background removal unit 135 provided in the B integrated circuit 130. It detects and removes the background component of the document from the image data. Further, the background detection unit 222 and the background removal unit 217 provided in the C integrated circuit 210 are used to detect and remove the background component of the document from the image data read by the CIS 50. In this image reading apparatus, usually, the document background density is determined based on image data obtained by reading the leading end of the document in the conveyance direction (a blank portion where no image is formed) during the document reading operation. The background removal is performed by subtracting the background density from the read image data (hereinafter, such a background removal process is referred to as a leading edge background removal mode). However, if you want to remove the background more accurately, determine the background density of the document based on the image data obtained by scanning not only the leading edge of the document in the transport direction but also the entire surface of the document. It is preferable to remove the background by subtracting the background density from the data (hereinafter, such a background removal process is referred to as a whole-surface background removal mode).

Therefore, in this embodiment, the background removal of the document is normally performed in the leading edge background removal mode. However, when an instruction from the user is received, the background removal of the document can be performed in the entire background background removal mode. ing.
FIG. 12 is a flowchart illustrating an example of processing performed by the image reading control 91 illustrated in FIG. 3 in consideration of selection of the background removal mode. In the image reading control 91, first, it is determined which function of copy, facsimile (Fax), or scanner (Scan) has been selected (step 201). Next, the image reading control 91 determines whether the conveyed document is a double-sided document or a single-sided document (step 202). If it is determined in step 202 that the original is a single-sided original, single-sided reading is performed by one pass (one-time original conveyance pass without using a reverse pass) (step 203).

  If it is determined in step 202 that the document is not a single-sided document, that is, if it is determined to be a double-sided document, it is next determined whether the conveyed document is a color document or a monochrome document (step 204). ). Here, when performing color reading, double-sided reading A by two passes (reverse passes) is performed (step 205). That is, the front and back surfaces of the document are both read by the CCD image sensor 78 without reading by the CIS 50.

On the other hand, if color reading is not performed in step 204, that is, if black and white reading is performed, whether the background removal of the original is performed in the leading edge background removal mode (leading edge) or the entire background removal mode (entire surface). Is determined (step 206). This determination is recognized by the user's selection using a control panel (not shown) provided on the scanner device 70, for example. Here, when the entire background removal mode is selected, double-sided reading B is performed by two passes (inversion pass) (step 207). This double-sided reading B is different from the double-sided reading A in step 205. Details thereof will be described later.
If the entire background background removal mode is not selected in step 206, that is, if the leading edge background removal mode is selected, double-sided simultaneous reading by one pass is performed without using the reverse path (step 208). That is, the front surface of the original is read by the CCD image sensor 78, and the back side of the original is read by the CIS 50 in the same conveyance path during the reading conveyance path.

FIG. 13 is a flowchart showing the flow of processing in step 205 described above, that is, double-sided reading A by two passes. In this process, first, the document is conveyed (step 301). Next, an image on one side (front surface) of the original is read by the CCD image sensor 78, image processing is performed by the A integrated circuit 110 and the B integrated circuit 130 (step 302), and surface image data after the image processing is output. (Step 303).
Further, the document from which the front image is read is reversed and conveyed (step 304). Next, the image on the other side (back side) of the document is read by the CCD image sensor 78, image processing is performed by the A integrated circuit 110 and the B integrated circuit 130 (step 305), and the back side image data after the image processing is output. (Step 306). Note that in double-sided scanning A with two passes, the leading edge base is removed in steps 302 and 305.

  FIG. 14 is a flowchart showing the flow of processing in step 208 described above, that is, double-sided reading (second double-sided reading mode) by one pass. In this process, first, the C integrated circuit 210 side is selected in the second SEL 202 (step 401). Next, the document is conveyed (step 402). Next, an image on one side (front surface) of the document is read by the CCD image sensor 78, and image processing by the A integrated circuit 110 and the B integrated circuit 130 is performed (step 403). Then, the B integrated circuit 130 side is selected in the first SEL 103 (step 404), and the surface image data after image processing is output (step 405).

  On the other hand, at the timing slightly delayed from step 403 described above, the other side (back side) image of the document is read by the CIS 50 and image processing is performed by the C integrated circuit 210 (step 406), and the obtained back side image data is obtained. Is stored in the memory 203 (step 407). Next, at the timing after the output of the front surface image data in step 405 described above is completed, the memory 203 side is selected by the first SEL 103 (step 408), and the back surface image data after image processing stored in the memory 203 is output. (Step 409). In this series of processing, Step 403 to Step 405 and Step 406 to Step 408 are performed substantially in parallel.

  Further, FIG. 15 is a flowchart showing the flow of processing in step 207 described above, that is, double-sided reading B (first double-sided reading mode) by two passes. In this process, first, the A integrated circuit 110 side is selected in the second SEL 202 (step 501). Next, the document is conveyed (step 502). Next, an image on one side (front surface) of the original is read by the CCD image sensor 78 and image processing is performed by the A integrated circuit 110 (step 503). The surface image data processed by the A integrated circuit 110 is stored in the memory. 203 (step 504). Further, in the A integrated circuit 110, the background detection unit 117 detects (pre-processes) the image parameter for background removal based on the read surface image data of the entire surface, and the obtained image parameter for background removal is B integrated. It is set in the background removal unit 135 of the circuit 130 (step 505). Then, the surface image data stored in the memory 203 is read out, image processing is performed in the B integrated circuit 130 (step 506), and the surface image data after image processing is output (step 507). In step 506, the background removal unit 135 performs background removal (processing) based on the set background removal image parameter.

  Further, the original from which the front image is read is reversed and conveyed (step 508). Next, an image on the other side (back side) of the original is read by the CCD image sensor 78 and image processing is performed by the A integrated circuit 110 (step 509). The back side image data processed by the A integrated circuit 110 is stored in the memory. 203 (step 510). Further, in the A integrated circuit 110, the background detection unit 117 detects (pre-processes) the image parameter for background removal based on the read back surface image data of the entire surface, and the obtained image parameter for background removal is B integrated. It is set in the background removal unit 135 of the circuit 130 (step 511). Then, the back surface image data stored in the memory 203 is read out, image processing is performed in the B integrated circuit 130 (step 512), and the surface image data after the image processing is output (step 513). In step 512, the background removal unit 135 performs background removal (processing) based on the set background removal image parameter.

  As described above, in this embodiment, when the entire background removal mode is selected, that is, a mode in which image processing is performed using image parameters based on image data for one page (entire surface) of the document (image processing When the mode requiring pre-processing is selected, the document is reversed and conveyed so that the images on both sides of the document are sequentially read. Therefore, the memory 203 only needs to be able to store image data for one page of the document. Cost reduction can be achieved. In particular, in the present embodiment, the memory 203 that is normally used for storing the image data read by the CIS 50 is used to store the image data read by the scanner device 70 as necessary. The apparatus configuration can be simplified and the memory 203 can be used effectively. Further, when the normal leading edge background removal mode is selected, that is, when the mode for performing image processing without using image parameters based on image data for one page of the document is selected, the document can be transported once. Since the images on both sides of the document are read, the image reading speed can be increased.

  In the present embodiment, when the entire background removal mode is selected, images on both sides of the document are read in two passes. However, the present invention is not limited to this. For example, a color image on the document is scanned. Image parameters based on image data for one page of the document are required, such as an automatic color adjustment (ACC) mode that automatically adjusts the hue, and an N-Up mode in which images of a plurality of documents are placed on a single sheet. Even when the image processing mode is selected, it is preferable to read the images on both sides of the document in two passes.

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. It is the block diagram which detailed the structure of the signal processing part. It is the block diagram which showed the structure of A integrated circuit (A integrated circuit). It is the block diagram which showed the structure of B integrated circuit (B integrated circuit). It is the block diagram which showed the structure of C integrated circuit (C integrated circuit). It is the flowchart which showed an example of the process performed by image reading control. It is a figure which shows an example of the user interface (UI) displayed on a control panel. (a), (b) is a figure for demonstrating the original pass of the single-sided reading mode by 1 pass, and the double-sided simultaneous reading mode by 1 pass. (a)-(d) is a figure for demonstrating the original pass of the double-sided reading mode by 2 passes. It is a flowchart which shows an example of the process which considered selection of the background removal mode performed by image reading control. It is a flowchart which shows the flow of the process in the double-sided reading A by 2 passes. It is a flowchart which shows the flow of the process in the single-sided reading by 1 pass. It is a flowchart which shows the flow of the process in the double-sided reading B by 2 passes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Document feeder, 31 ... 1st conveyance path, 32 ... 2nd conveyance path, 33 ... 3rd conveyance path, 34 ... 4th conveyance path, 35 ... 5th conveyance path, 36 ... 6th conveyance path, 40 ... Ejection tray, 50 ... CIS, 51 ... Glass, 52 ... LED, 53 ... Selfoc lens, 54 ... Line sensor, 55 ... Control member, 70 ... Scanner device, 74 ... Illumination lamp, 77 ... Imaging lens, 78 ... CCD image sensor, 79 ... drive substrate, 80 ... processing device, 81 ... signal processing unit, 82 ... AFE, 83 ... ADC, 90 ... control unit, 91 ... image reading control, 92 ... CCD / CIS control, 93 ... lamp control 94 ... Scan control 95 ... Conveyance mechanism control 100 ... First image processing circuit 101 ... First CPU 102 ... AFE / ADC 103 ... First selector (first SEL), 110 ... A integrated circuit (ASIC-A), 117 ... background detection unit, 130 ... B integrated circuit (ASIC-B), 135 ... background removal unit, 200 ... second image processing circuit, 201 ... second CPU, 202 ... second selector (second SEL), 203 ... memory, 210 ... C integrated circuit (ASIC-C)

Claims (10)

A paper feeder for feeding the original,
A transport path through which a document fed from the paper feed unit is transported;
A first sensor that reads an image on one side of a document from one side of the conveyance path;
A second sensor that reads an image on one side of the document from the other side facing the one side through the conveyance path;
A reversing conveyance path for reversing and conveying the front and back of the document whose image is read by the first sensor to the conveyance path,
When setting image parameters for performing image processing on the image data using image data for one page of the document, one side of the document conveyed on the conveyance path is read by the first sensor, and the inversion is performed. A first double-sided reading mode in which the document is reversely conveyed to the conveyance path via the conveyance path and the other side of the document is read by the first sensor;
When image parameters for performing image processing on the image data using image data for one page of the document are not set, the images on the front and back sides of the document are transported to the transport path once in the transport path. And a second double-sided reading mode read by the second sensor.   The image reading apparatus according to claim 1, further comprising a memory that stores image data read by the first sensor or the second sensor.   The image reading apparatus according to claim 2, wherein the memory has a capacity corresponding to image data of less than two pages of a document.   In the first double-sided reading mode, image data for one page of a single-sided original read by the first sensor is stored in the memory and image processing is performed based on the image data for one page of the single-sided original. Parameters are set, the image data read from the memory is subjected to image processing using the image processing parameters and output, and the other one-side original page read by the first sensor after being reversely conveyed. Image data is stored in the memory and image processing parameters are set based on the image data for one page of the other side of the original, and the image processing parameters are used for the image data read from the memory. 3. The image reading apparatus according to claim 2, wherein the image is output after being subjected to image processing.   In the second duplex reading mode, image data for one page of a single-sided document read by the first sensor is output, and one page of another single-sided document read by the second sensor. The image reading apparatus according to claim 2, wherein the image data is output after being stored in the memory. A paper feeder for feeding the original,
A transport path through which a document fed from the paper feed unit is transported;
A first sensor that reads an image on one side of a document from one side of the conveyance path;
A second sensor that reads an image on one side of the document from the other side facing the one side through the conveyance path;
A reversing conveyance path for reversing and conveying the front and back of the document whose image has been read by the first sensor to the conveying path;
After reading one side of the document conveyed on the conveyance path by the first sensor when reading the image data of the document or when performing preprocessing of processing performed after reading the image data of the document An image reading apparatus comprising: a reading control unit that causes the original to be reversely conveyed to the conveyance path via the reverse conveyance path and causes the other side of the original to be read by the first sensor.   7. The image reading apparatus according to claim 6, wherein the preprocessing is parameter setting for removing the background of the original from the image data. First reading means for reading image data of the first side of the document;
Second reading means for reading image data of the second side of the document;
Storage means for storing the image data of the second surface read by the second reading means;
An output unit that outputs the image data of the second surface stored in the storage unit after the image data of the first surface read by the first reading unit is output;
When setting image parameters for performing image processing on the image data of the first surface based on the image data of the first surface read by the first reading unit, the first surface is stored in the storage unit. An image reading apparatus having transfer means for transferring the image data.   The image reading apparatus according to claim 8, wherein the transfer unit reads the image data of the first surface stored in the storage unit when performing image processing based on the obtained image parameter.   9. The image reading apparatus according to claim 8, wherein when the image parameter is set, only the first reading unit is used for reading a document.

Images