JP2006229706A - Image reader and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader acquiring an image on a level corresponding to an original image without shutting down an apparatus even if an abnormal state occurs in an image data line, and also to provide an image forming apparatus. <P>SOLUTION: The image reader has: an irradiating means for irradiating an original by a light source; a light receiving means for receiving reflected light or transmitted light of the irradiating means by a photoelectric converter having at least two types of optical spectrum sensitivity characteristics; an electric data outputting means for outputting electric data corresponding to an original image for the number of sensitivity characteristics; an image data generating means for using one type or more among pieces of the outputted electric data to generate data as image data; and an abnormality detecting means for detecting a fault or an abnormal state of an image data line to be used. The reader uses another piece of image data when there is a fault or an abnormal state in the image data line to be used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to optical control of an image scanner, and more particularly to an image reading apparatus and an image forming apparatus that can acquire an image at a level according to an original image without bringing down the apparatus even when an abnormal state occurs.

As a prior art example, there is a “color image reading apparatus” that focuses on a blue light receiving element array and increases the amount of received light (for example, see Patent Document 1).
In addition, there is a “color image reading apparatus” that retracts an ND filter when reading with a photoelectric conversion element having low sensitivity (see, for example, Patent Document 2).
In addition, there is a “digital color copying machine” that issues a warning when a density difference between adjacent areas is small when copying a multicolor original in a single color (see, for example, Patent Document 3).
JP-A-9-172519 JP 2000-253207 A JP-A-6-225167

As another prior art example, an original is irradiated with a white exposure lamp, the reflected light or transmitted light is received by a photoelectric conversion element, and electrical data is output in the number of sensitivity characteristics in units of lines, one of which is used. In an image reading apparatus that uses image data, there is an image reading apparatus that can change the amount of incident CCD light per line when RGB B is selected as the selected image data.
In addition, there is a case where reading of use of R and B data when RGB G is NG is performed, the switching selection is input from the operation display unit, and the failure and switching state are displayed.

  However, in a conventional image forming apparatus or image reading apparatus capable of color reading having a plurality of spectral sensitivities, one type of data is used from among a plurality of sensitivity spectra for reading in the monochrome mode. It is reproduced.

  For example, in red (R), green (G), and blue (B), the density is often expressed by using monochrome read data for green that is close to the visibility characteristic. In this way, it is common to use one type of data for monochrome reading. However, when there is an abnormality in the data system (for example, when there is an abnormality in the G reading system data, there may be a hardware abnormality such as CCD, analog amplifier circuit, AD converter, field memory, etc.) Affects image acquisition. For example, an abnormal image occurs and becomes unusable. In addition, the unusable time (downtime) of the machine until repair is a large value, and there is a need to improve the time for waiting for arrival of maintenance workers and replacement parts.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image reading apparatus and an image forming apparatus that can acquire an image even in an abnormal state and at a level according to an original image without bringing down the machine. And

  In order to achieve such an object, the invention described in claim 1 is an irradiation means for irradiating a document with a light source, and a photoelectric conversion element having at least two kinds of light spectrum sensitivity characteristics for reflected light or transmitted light of the irradiation means. Light receiving means for receiving light, electric data output means for outputting electric data corresponding to the image of the document for the number of sensitivity characteristics, and image data generating means for generating one or more types of output electric data as image data And an abnormality detecting means for detecting failure or abnormality of the used image data line, and when the used image data line is in failure or abnormal condition, other image data is used. .

  According to a second aspect of the present invention, in the first aspect of the invention, the electrical data output means includes a specific pixel value holding unit in which a value of a specific pixel in main scanning is written, and a normal setting range in advance with respect to the value of the specific pixel. And an identifier adding unit that adds an identifier indicating an error to the electrical data when the value is outside the normal setting range.

  According to a third aspect of the invention, in the second aspect of the invention, the abnormality detection means determines which image data line has a failure or abnormality based on the presence or absence of an identifier indicating an error. And

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, when the abnormality detecting means detects a failure or abnormality during shading before scanning, it uses other image data. Features.

  According to a fifth aspect of the present invention, the image reading apparatus according to any one of the first to fourth aspects is provided.

  According to the present invention, a document is irradiated with a light source, the reflected light or transmitted light is received by a photoelectric conversion element having at least two types of optical spectrum sensitivity characteristics, and electrical data corresponding to the document image is received by the sensitivity characteristics. Output several minutes, use one or more of them as image data, and if the image data line used is faulty or abnormal, other data will be used. Images can be acquired even at levels similar to images.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is an overall configuration diagram of a color image reading apparatus according to an embodiment of the present invention. The configuration of the scanner body will be described.

  As shown in FIG. 1, the original placed on the platen glass 8 is irradiated by the illumination lamp 2 configured integrally with the first mirror 3, and the reflected light is configured integrally with the first mirror 3. Scanning is performed by the second mirror 5 and the third mirror 4. Thereafter, the reflected light is focused by the lens 1 and irradiated to the SBU 10 on which the color CCD is mounted, thereby being photoelectrically converted to RGB.

  The first mirror 3, the illumination lamp 2, the second mirror 5, and the third mirror 4 are movable in the left-right direction using the traveling body motor 9 as a drive source.

  When an ADF (Auto Document Feeder) that is an automatic document feeder is used, the document is read when it passes through the reading position between the DF document glass 6 and the reflection guide plate 20 for both reading of the front and back surfaces. Irradiated by the illumination lamp 2 (irradiation means) moved in the vicinity of the position, the reflected light is scanned by the first mirror 3 and the second mirror 5 and the third mirror 4 that are integrally formed. Thereafter, the reflected light is focused by the lens 1 and irradiated to the SBU 10 on which the color CCD is mounted, thereby being photoelectrically converted to RGB.

  The scanner body is equipped with an SCU 7 that controls the operation of the color image reading apparatus including the scanner body and the ADF.

  As shown in FIG. 3, the reflected light of the original that has entered the color CCD 42 (light receiving means) of the SBU 10 is converted into RGB analog signals having voltage values corresponding to the light intensity in the color CCD 42. The analog signals for each color of RGB are output separately in odd bits (ODD) and even bits (EVEN).

  The analog image signal of the SBU 10 is obtained by removing the dark potential portion from each analog processing circuit 32 of the VIOB 31 (electrical data output means), combining odd bits and even bits, and adjusting the gain to a predetermined amplitude. The signal is input to the D converter 33 and converted into a digital signal.

  The digitized image signal is subjected to shading correction by the shading ASIC 34, input from the VIOB 31 to the SCU 7, and subjected to image processing such as gamma correction and MTF correction by the IPU 35 (image data generating means) on the SCU 7, and then synchronized. A video signal is output together with a signal and an image clock.

  The video signal output from the IPU 35 is output to the OIPU 36. The video signal output to the OIPU 36 undergoes predetermined image processing in the OIPU 36 and is input to the SCU 7 again. The video signal input again to the SCU 7 is input to the VIDEO input switching circuit 37.

  The other input of the VIDEO input switching circuit 37 is a video signal output from the IPU 35, and the OIPU 36 can select whether or not to execute image processing.

  The video signal output from the VIDEO input switching circuit 37 is input to the SIBC 238 of the memory controller that manages the image data storage means (SDRAM), and is stored in the image memory 106 formed of SDRAM.

  The image data stored in the image memory 106 is sent to the SCSI controller 39 and transferred to an external device such as a personal computer or a printer.

  Further, the CPU 108, the ROM 109, and the RAM 110 are mounted on the SCU 7, and the CPU 108 communicates with an external device such as a personal computer by controlling the SCSI controller 39 of the external interface unit (external I / F).

  Similarly, the CPU 108 sends the video signal output from the VIDEO input switching circuit 37 to the IEEE 1394 I / F via the IEEE 1394 controller ISIC 40 which is an external I / F function and the network I / F via the NIC 41 which is a network scanner controller. Use / F to communicate with external devices such as personal computers and printers. Although not explicitly shown in FIG. 3, the CPU 108 is electrically connected to the ISIC 40 and the NIC 41.

  The CPU 108 also performs motor control for moving the traveling body, and controls the motor driver 112 to control the traveling body motor 9 that is a stepping motor of the scanner body, an ARDF paper feed motor (not shown), and a transport motor. Timing control (not shown) is also performed.

  The ADU 42 shown in FIG. 2 has a function of relaying power supply of electrical components used for the ARDF unit. The ADU 42 is connected to the VIOB 31.

  An input port (not shown) connected to the CPU 108 of the SCU 7 is connected to the SOP 43 which is a main body operation panel via the VIOB 31.

  A start switch (not shown) and an abort switch (not shown) are mounted on the SOP 43 of the main body operation panel, and a liquid crystal LCD 117 is used as a display device. In addition, a matrix touch switch 116 is provided on the liquid crystal display. When the user presses an input symbol displayed on the liquid crystal display, the touch switch reacts and is input from the pressed coordinate information (corresponding to the display information). Determine the contents. The LCD controller 115 performs liquid crystal display control and touch switch input control. When the touch switch is pressed, the LCD controller 115 detects that the CPU 108 is switched on.

  The flow of image data is SBU-> IPU-> memory control LSI (SIBC2)-> SCSI controller-> external device (such as a personal computer). Further, ON / OFF of image output from the CPU 108 is installed as a known technique in an image processing LSI (IPU) (not shown) and is controlled by rewriting an internal register.

Next, the flow of RGB image data is shown in FIG.
The analog video signal photoelectrically converted by the color CCD 42 of the SBU 10 for each of odd-numbered RGB (ODD) and even-numbered bit (EVEN) of RGB is input to the VIOB 31 via the buffer 45 on the SBU 10.

  Each signal is represented by R-ODD (RO), R-EVEN (RE), G-ODD (GO), G-EVEN (GE), B-ODD (BO), and B-EVEN (BE). The analog video signal for each of the odd and even bits is input to the analog processing circuit 32 on the VIOB 31.

  The signal input to the analog processing circuit 32 is combined into an even number and an odd number via an internal gain amplifier (not shown) whose output level can be finely varied for every odd bit and even bit, and is output as an analog video signal.

  Two channels of D / A converters 44 are connected to the gain control terminal of each gain amplifier, and the output voltage of the D / A converter 44 is varied in an analog manner so that the gain for the output analog video signal is even or odd. Can be varied.

  The CPU 108 on the SCU 7 sets the output voltage of the D / A converter 44. Since the D / A converter 44 has a reference voltage of 5V and a bit number of 8 bits, the CPU 108 can set the output voltage from 0 to 5V in 255 stages. The setting of the CPU 108 is digital (integer) from 0 to 255.

  The analog video signal output by combining the even and odd numbers from the analog processing circuit 32 is input to the A / D converter 33 for each RGB, and the A / D converter 33 converts the analog video signal into an 8-bit digital video signal. To do.

  A D / A converter is connected to the reference (ref) setting terminal of the A / D converter 33 in the same manner as described above. By changing the output voltage of the D / A converter 44 in an analog manner, the A / D converter 33 The digital output value can be varied.

  Digital video data digitally converted by the A / D converter 33 is input to the shading ASIC 34. The shading ASIC 34 mainly performs shading correction. In addition to this, there is a peak detector (not shown) that can detect the peak value of one line in the main scanning direction.

  The peak detection unit has a function of storing the peak value of one line. The CPU 108 on the SCU 7 can read the stored peak value of one line.

  Assuming that the input analog video signal of the analog processing circuit 32 is Vin and the output analog video signal (output signal of the analog processing circuit) amplified by a certain gain value G that is an analog processing circuit is Vout, Vout = G × Vin. . The A / D converter 33 performs digital conversion with the reference voltage (reference voltage) as the maximum output. If the reference voltage is Vref, the 8-bit digital output value D is D = (Vout / Vref) × 255.

  Next, in the above configuration, an example will be described in which an abnormality occurs in shading data acquired by the shading ASIC 34 due to, for example, a defect before the A / D converter.

  In general, in an image reading apparatus, a white plate having a high reflectance and a good balance is used for each RGB wavelength spectrum immediately before image acquisition, and shading processing is performed for each RGB. The shading correction is correction of CCD sensitivity unevenness and illuminance distribution variation of the light source, and is an indispensable process for the digital optical system.

When performing shading correction, first, shading data is generated. In this embodiment, the shading data is obtained from a simple addition average of 16 lines of image data obtained by reading a white reference plate.
Shading data = (1st line data + 2nd line data + ... + 16th line data) / 16

In general shading correction, corresponding pixels are calculated from the shading data.
Maximum subtraction amount: 255 (8bit)
The shading calculation formula is shown below. The basic formula of shading is data after shading correction = read data / shading data × 255
Here, when the read data is D (n), the shading data is S # (n), and the data after shading correction is D # (n),
D # (n) = (D (n) / S # (n)) × 255 (n is an arbitrary effective pixel number EX.1 to 7300).
At this time, assuming that shading data is D, pre-shading image data Din is image data after shading, and Ds is RGB, each RGB data is individually executed. Therefore, each RGB data is expressed with a lower case rgb.
D # (n) g = (D (n) g / S # (n) g) × 255
Each RGB main scan peak data of the white reference plate is usually about 220 digits and the analog gain is adjusted. However, when the shading data S # (n) g generated during shading is extremely low (for example, S # (n) r, S # (n) b: Compared to 208 digits and 209 digits, when only this S # (n) g data is 32 digits), it can be clearly determined that this G system is abnormal.

FIG. 6 shows the state of the registers in the ASIC as an example. The address (hex) of the shading data starts from 8000H and is written in 8 bits from b7 to b0.
A specific pixel value (8 bits) 208 of 8000H: R shading data is described.
8001H: A specific pixel value (8 bits) 32 of G shading data is described.
8002H: Specific pixel value (8bit) 209 of shading data of B is described
8004H: RGB shading data error flag (3 bits) b2: R, b1: G, b0: B, b7 to b4 are not used, and b1 is set to 1 to indicate an error state.
In this case, even if the value of D (n) g is small (dark side), S # (n) g has a large correction coefficient, so it is skipped to the bright side. (In the image, the abnormal pixel portion becomes a white streak. If the abnormality is not a pixel unit of the CCD but a circuit, the abnormal range extends from the streak to the entire surface).

  As described above, although data of shading abnormality flows after the shading ASIC, the specific pixel (EX. Center number) of the main scan is stored in the G internal register (specific pixel value holding unit) inside the shading ASIC. Value) is written. Specify a normal setting range (EX.64 digits or more) in advance for this value, and provide a register (identifier adding part) in which an error flag (an identifier indicating an error) is set if any other value (for example, 32 digits) is reached. deep.

  Although it can be implemented even when the CPU 108 reads the data and makes the judgment in the CPU processing, the load on the CPU side read through the CPU bus is less likely to be implemented by hardware on the ASIC side. Similarly, R and B have the same configuration, and it is possible to implement the same thing as three data.

  By providing such a function in the image processing portion of each RGB image data in this way, the CPU 108 can easily determine which RGB data system has an abnormality.

  In ordinary text manuscripts, the manuscript occupies a larger proportion of characters than color graphics, and the colors are currently black and white (gray) in most cases. There is no significant difference in the reflectance. Therefore, as a substitute when G cannot be used, it is often possible to substitute B or R data.

  FIG. 5 shows the state of monochrome image usage data. The figure on the left shows the normal state (the white area is expressed during use (G data is used). The figure on the right shows the occurrence of an abnormality (G abnormality: expressed in darkness, the abnormality is presented at the bottom) and the substitute data is in use. (R selection, change in white) (B display does not change.) As for display devices, TN, STN, and TFT methods are generally used for LCDs, but printed pictures are used. There is a means for displaying by providing a light source such as an LED or a light bulb underneath.

When R is selected as in this example, the CPU writes the R selection into the monochrome selection register of the IPU.
As shown in FIG. 7, in the example, a selection register is installed in the IPU register 9000H, and 9000H: RGB selection data flags (3 bits) b2: R, b1: G, b0: B, and b7 to b4 are not used. , B21 is set to 1, indicating the R selection state. The IPU selects R data from the RGB data fetched into the IPU, and passes it through the image data bus to the subsequent circuits after the memory controller (the same applies to other colors). In this embodiment, 9001H: output destination selection flag (3 bits) b2: OPIU, b1: memory controller, b0: other (image evaluation apparatus, etc.), b7 to b4 are not used. 1 stands for B1, indicating the memory controller selection state.

  As described above, according to the embodiment of the present invention, an original is irradiated with a light source, and the reflected light or transmitted light is received by a photoelectric conversion element having at least two kinds of optical spectrum sensitivity characteristics, and the electric light corresponding to the original image is received. In an image reading device that outputs data for the number of sensitivity characteristics described above and uses one or more of them as image data, if the image data line used is faulty or abnormal, other data is used, so abnormal Even in the state, the image can be acquired at a level according to the original image without bringing down the machine.

  Further, according to the embodiment of the present invention, failure or abnormality is determined at the time of shading before scanning, and other image data is used even in an abnormal state, so it is not necessary to obtain an image based on abnormal data, downtime Thus, a substitute image can be obtained promptly before scanning each time without causing any trouble.

  As mentioned above, although embodiment of this invention was described, it is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the summary.

  The present invention can be applied to optical control of PPC and facsimile.

1 is a diagram illustrating an overall configuration of a color image reading apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating an overall configuration of an image reading apparatus according to the present invention. It is a block diagram which shows the flow of the image data of the image reading apparatus which concerns on this invention. It is a block diagram regarding image control of the image reading apparatus according to the present invention. It is a figure which shows the state of monochrome image use data. It is a table | surface which shows an example of the mode of the register | resistor in shading ASIC. It is a table | surface which shows an example of the mode of an IPU internal register.

Explanation of symbols

1 Lens 2 Illumination lamp (irradiation means)
3 First mirror 4 Third mirror 5 Second mirror 6 Document glass for DF 7 SCU
8 Document platen glass 9 Traveling body motor 10 SBU
13 Document Set Sensor 19 Registration Sensor 22 Paper Discharge Sensor 27 Document Trailing Edge Detection Sensor 28 Document Width Size Detection Sensor 29 Document Length Size Detection Sensor 1
30 Document length size detection sensor 2
31 VIOB (electrical data output means)
32 Analog processing circuit 33 A / D converter 34 Shading ASIC
35 IPU (image data generating means)
36 OIPU
37 VIDEO input switching circuit 38 SIBC2
39 SCSI
40 ISIC
41 NIC
42 Color CCD (light receiving means)
43 SOP
44 D / A converter 45 Buffer 106 Image memory 108 CPU (abnormality determination means)
109 ROM
110 RAM
115 LCD controller 116 Matrix touch SW
117 LCD

Claims (5)

Irradiating means for irradiating a document with a light source;
A light receiving means for receiving reflected light or transmitted light of the irradiating means by a photoelectric conversion element having at least two kinds of optical spectrum sensitivity characteristics;
Electrical data output means for outputting electrical data corresponding to the image of the document for the number of sensitivity characteristics;
Image data generating means for generating one or more types of the output electrical data as image data;
An abnormality detecting means for detecting failure or abnormality of the image data line used,
An image reading apparatus using other image data when the image data line to be used is faulty or abnormal. The electrical data output means includes
A specific pixel value holding unit in which a value of a specific pixel of main scanning is written;
A normal setting range is specified in advance for the value of the specific pixel, and when the value is outside the normal setting range, an identifier adding unit that adds an identifier indicating an error to the electrical data;
The image reading apparatus according to claim 1, further comprising: The abnormality detection means includes
The image reading apparatus according to claim 2, wherein an image data line having a failure or abnormality is determined based on the presence or absence of an identifier indicating the error.   4. The image reading apparatus according to claim 1, wherein when the abnormality detection unit detects a failure or abnormality during shading before scanning, another image data is used. 5.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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