JP2009005289A - Image reading apparatus, and image sensor discrimination method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus and an image sensor discrimination method for accurately discriminating the type of an image sensor by a simple method. <P>SOLUTION: A resolution switching signal is input to the image sensor 14, a resolution is detected from an output signal of the image sensor 14 during reading operation and the type of the image sensor 14 is discriminated based on the resolution, so that simple and accurate discrimination can be made. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image reading apparatus and an image sensor discrimination method.

  In an image reading apparatus that reads an original image with an image sensor, an image sensor selected from a plurality of types of image sensors having different characteristics such as reading speed may be incorporated into the apparatus at the time of manufacture. The interface of such an image sensor is made common regardless of the manufacturer, and the function of each signal line connecting the image sensor and its control unit is shared to some extent. However, the functions of some signal lines or the operation for signals input from the signal lines may differ depending on the type of image sensor. Specifically, for example, the resolution switching signal for setting the resolution at the time of the reading operation in the image sensor may be recognized differently depending on the type of the image sensor.

The controller incorporates firmware that can handle multiple types of image sensors, and the operator can select the type of image sensor to switch the operation according to the type of image sensor. It is configured to be able to.
JP 2000-69289 A

  By the way, the type of the image sensor is determined with reference to a barcode or the like attached to the image sensor by the operator. For this reason, the operator must surely determine the type of the image sensor incorporated and make an appropriate setting, which is troublesome and may cause a failure to perform a correct reading operation if a setting error occurs. there were.

  As a countermeasure, a method of automatically determining the type of the built-in interface by newly providing a signal line for type discrimination and connecting it to the control unit of the image sensor is also conceivable. However, in this case, there is a problem that the interface of the image sensor cannot be made common and the cost is increased.

  The present invention has been completed based on the above circumstances, and provides an image reading apparatus and an image sensor discrimination method capable of accurately discriminating the type of an image sensor by a simple method. Objective.

  As means for achieving the above object, the image reading apparatus according to the first invention is capable of switching the resolution based on the resolution switching signal and reading the same resolution switching signal at different resolutions. An image reading apparatus incorporating an image sensor selected from a plurality of types of image sensors that perform an operation, an input means for inputting a resolution switching signal to the image sensor, and an output signal from the image sensor Determination means for detecting the resolution during the reading operation based on the resolution and determining the type of the image sensor based on the resolution.

  According to the first invention, the resolution switching signal is input to the image sensor, the resolution is detected from the output signal of the image sensor during the reading operation, and the type of the image sensor is determined based on the resolution. Accurate discrimination is possible.

  In a second aspect based on the first aspect, the resolution switching signal is a time-series signal composed of binary values of on and off.

  According to the second invention, since the resolution switching signal is a time-series signal, various information can be transmitted with a small number, and the number of signal lines can be suppressed.

  According to a third invention, in the first or second invention, a white area and a black area are provided with reference portions provided adjacent to each other in the main scanning direction of the image sensor. The reference portion is read, a pixel position corresponding to the boundary position between the white area and the black area is obtained from the output signal, and the resolution of the image sensor is detected based on the pixel position.

  According to the third invention, the resolution can be accurately detected by a simple method.

  According to a fourth aspect, in the third aspect, when the resolution of the image sensor is detected, the image sensor and the reference unit are moved to a position facing each other.

  According to the fourth aspect of the invention, when detecting the resolution of the image sensor, the image sensor and the reference unit are moved relative to each other to be opposed to each other, thereby disposing the reference unit in a place that does not interfere with the document reading operation. It becomes possible to do.

  In a fifth aspect based on any one of the first to fourth aspects, the determination unit detects the resolution based on an amount of effective pixel data acquired from the output signal per unit scan of the image sensor. To do.

  According to the fifth invention, the resolution can be accurately detected by a simple method.

  According to a sixth invention, in any one of the first to fifth inventions, the input means is connected to the image sensor by a plurality of signal lines, and is in accordance with the type of the image sensor determined by the determination means. The type of the signal transmitted through at least a part of the plurality of signal lines is switched.

  According to the sixth aspect, since the type of the signal transmitted through the signal line is switched according to the type of the image sensor, more types of image sensors can be handled.

  According to a seventh aspect of the present invention, there is provided an image sensor discrimination method comprising: a plurality of types of image sensors that are capable of switching resolution based on a resolution switching signal and that perform reading operations at different resolutions with respect to the same resolution switching signal; A method for determining a type of an image sensor selected from the above, wherein a resolution switching signal is input to the image sensor to perform a reading operation, and a reading operation is performed based on an output signal from the image sensor. The resolution is detected, and the type of the image sensor is determined based on the resolution.

  According to the seventh aspect, since the resolution switching signal is input to the image sensor, the resolution is detected from the output signal of the image sensor during the reading operation, and the type of the image sensor is determined based on the resolution. Accurate discrimination is possible.

  According to the present invention, the resolution switching signal is input to the image sensor, the resolution is detected from the output signal of the image sensor during the reading operation, and the type of the image sensor is determined based on the resolution. Discrimination becomes possible.

  Next, an embodiment of the present invention will be described with reference to FIGS.

(Configuration of MFP)
In the present embodiment, an example in which the present invention is applied to a multifunction device 1 (an example of an image reading apparatus) having a scanner function, a printer function, a copy function, a facsimile function, and the like will be described. FIG. 1 is an external perspective view of the multifunction device 1, FIG. 2 is an enlarged cross-sectional view of a main part of the document reading unit 3, and FIG. 3 is a plan view of the reference member 20.

  As shown in FIG. 1, the multifunction machine 1 includes a main body 2 that houses an image forming unit 38 (see FIG. 4) that prints an image on a sheet, and a document reading unit 3 that reads a document above the main body 2. . An operation panel 4 provided with various buttons, a liquid crystal display, and the like is provided on the front side of the document reading unit 3, and the operation panel 4 can display an operation state and input a user operation.

  The document reading unit 3 includes a flat bed unit 6 and a document cover unit 7 that covers the upper part of the document reading unit 3 so as to be openable and closable. A first platen glass 8 and a second platen glass 9 having a transparent rectangular shape are provided side by side on the upper surface of the flat bed portion 6. The document cover unit 7 includes an ADF (automatic document feeder) 11, a document tray 12, and a discharge tray 13. The ADF 11 transports the documents placed on the document tray 12 one by one, transports the documents to a position facing the second platen glass 9, and then discharges them onto the discharge tray 13.

  An image sensor 14 is provided below the first platen glass 8. The image sensor 14 is of a CIS (Contact Image Sensor) type, and includes a CMOS image sensor 15, an optical element 16 made of a lens, and a light source 17 made of RGB light emitting diodes. The CMOS image sensor 15 includes a plurality of photodiodes arranged in a line in the main scanning direction (perpendicular to the paper surface), and reflects the reflected light when light is applied to the document from the light source 17 through the optical element 16. The light is received by individual photodiodes, and the light intensity (brightness) of the reflected light is converted into an electrical signal for each pixel and output.

  The reading of the original is performed by placing the original on the first platen glass 8 or using the ADF 11. In the former case, the image sensor 14 is moved in the sub-scanning direction (arrow A direction in FIG. 2) by the power of the step motor 40 (an example of the moving means, see FIG. 4). The original is read line by line in a direction perpendicular to the paper surface. In the latter case, when the image sensor 14 is fixed at a position facing the second platen glass 9 and the document is conveyed to a position facing the second platen glass 9 by driving the ADF 11, the reading of the document is performed. Is performed line by line in the main scanning direction.

  The flat bed portion 6 is provided with a reference member 20 shown in FIG. 3 on an inner surface portion adjacent to the second platen glass 9 of the housing. The reference member 20 has a rectangular plate shape, is elongated in the main scanning direction, and has a length dimension that is slightly larger than one line reading area of the image sensor 14. The reference member 20 is divided into two in the sub-scanning direction. One is a white reference portion 21 and the other is a resolution measurement reference portion 22 (an example of a reference portion). The white reference portion 21 is white with a uniform density throughout. The resolution measurement reference unit 22 has a black region 22A at one end in the main scanning direction, a white region 22B at the remaining portion, and the black region 22A and the white region 22B are arranged adjacent to each other in the main scanning direction. .

(Electric configuration of the multifunction device)
Next, the electrical configuration of the multifunction machine 1 will be described. FIG. 4 is a block diagram schematically showing the electrical configuration of the multifunction machine 1.

  The multi-function device 1 includes a CPU 31 (an example of a determination unit), a ROM 32, a RAM 33, an NVRAM (nonvolatile memory) 34, an ASIC 35 (an example of an input unit), a network interface 36, a facsimile interface 37, and the like. It has.

  The ROM 32 stores various control programs for controlling the multifunction machine 1, various settings, initial values, and the like. The RAM 33 is used as a work area from which various control programs are read or as a storage area for temporarily storing image data. The ASIC 35 is connected to the image forming unit 38, the document reading unit 3, the operation panel 4, and the like described above. The CPU 31 controls each component of the multifunction device 1 via the ASIC 35 while storing the processing result in the RAM 33 or the NVRAM 34 according to the control program read from the ROM 32.

  A computer or the like is connected to the network interface 36, and mutual data communication is possible via the network interface 36. The facsimile interface 37 is connected to a telephone line (not shown), and facsimile data can be communicated with an external facsimile apparatus or the like via the facsimile interface 37.

(Function of signals sent and received between the image sensor and ASIC)
In the multifunction device 1 of the present embodiment, one of two types of image sensors 14 (hereinafter, one is referred to as A type and the other as B type) having different characteristics such as reading speed at the time of manufacture is selected, and the document reading unit 3 is incorporated. The interfaces of both types of image sensors 14 are made common, and both are connected to the ASIC 35 via a flexible flat cable 39 (see FIG. 4) having 11 signal lines. .

  FIG. 5 shows the number of the signal line connecting the A-type image sensor 14 and the ASIC 35 (specifically, the pin number of the connector connecting the flexible flat cable 39 and the ASIC 35) and the function of the signal. The first signal is a signal output from the image sensor 14 to the ASIC 35, that is, an analog image signal. Signals Nos. 2 to 11 are all drive signals input to the image sensor 14 from the ASIC 35 side, and are a resolution switching signal for switching the resolution during the reading operation, and a drive start pulse for giving a drive start timing for each line. The signal includes a signal, a drive clock signal, a current supply common signal that is commonly supplied to the anode side of each of the light emitting diodes of RGB as the light source 17, and a current supply signal that is supplied to the cathode side for each light emitting diode of each color.

  The function of each signal line in the B-type image sensor 14 (that is, signal pin arrangement) is the same as that of the A type from No. 1 to No. 8, and is different from the A type from No. 9 to No. 11. That is, in the A type image sensor 14, the number 9 is B, the number 10 is G, and the number 11 is a current supply signal to the R light emitting diode, whereas in the type B image sensor 14, the number 9 is G, number 10. Is a current supply signal to the light emitting diode of R and No. 11 of B.

  In the A-type and B-type image sensors 14, the resolution at the time of the reading operation can be set to any one of three types of 1200 dpi, 600 dpi, and 300 dpi based on the resolution switching signal. FIG. 6 is a timing chart for explaining the relationship between the resolution switching signal (MODE) and the resolution setting in each type of image sensor 14.

  As shown in FIG. 6, the resolution switching signal is a time-series signal composed of binary values of H and L, and the A-type and B-type image sensors 14 change the value of the resolution switching signal at predetermined timings different from each other. Check and set the resolution based on that value. That is, both the A-type and B-type image sensors 14 count in synchronization with the drive clock signal (CIS_CLK), and the count is set to 0 when the drive start pulse signal (SP (TG)) is received. The value of the resolution switching signal (MODE) at the 20th clock is acquired. Subsequently, the A-type image sensor 14 acquires the value of the resolution switching signal (MODE) at the 40th clock, and the B-type image sensor 14 acquires the value of the 44th clock.

  The A-type and B-type image sensors 14 set the resolution to 1200 dpi when the values of the first and second resolution switching signals are both H (see MODE1200 in FIG. 6). Both types of image sensors 14 set the resolution to 600 dpi when the values of the first and second resolution switching signals are both L (MODE 600). Further, both types of image sensors 14 set the resolution to 300 dpi when the value of the first resolution switching signal is H and the second value is L (MODE 300).

(Sensor discrimination processing)
Next, an operation of sensor discrimination processing for discriminating the type of the image sensor 14 will be described. FIG. 7 is a flowchart showing the flow of the sensor discrimination process, and FIG. 8 is a timing chart showing an example of the output signal of the image sensor 14 during the sensor discrimination process.

  This sensor determination process is executed under the control of the CPU 31 when the multifunction device 1 is powered on. When starting the sensor determination process, the CPU 31 first moves the image sensor 14 to the initial position (home position) by the step motor 40 (S101), and then moves the image sensor 14 to a position facing the white reference portion 21. (S102).

  Then, various drive signals such as a drive clock signal (CIS_CLK), a drive start pulse signal (SP (TG)), and a resolution switching signal (MODE) are input to the image sensor 14 by the ASIC 35, and the resolution is set (S103). . Here, as shown in FIG. 6, the resolution switching signal (MODE) input to the image sensor 14 takes a value of H at the 20th clock, a value of H at the 40th clock, and a value of L at the 44th clock. . Therefore, when the image sensor 14 connected to the ASIC 35 is an A type, the resolution is set to 1200 dpi based on the resolution switching signal (MODE), and when the image sensor 14 is a B type, the resolution is set to 300 dpi.

  Then, CPU31 performs the process which adjusts the light quantity of the light emitting diode of each color which is the light source 17 (S104). Specifically, first, the white reference portion 21 is scanned by the image sensor 14 to read one line. In this reading operation, each current supply signal is input so that each color light emitting diode emits light with a predetermined (temporary) light amount.

  During the reading operation, the image sensor 14 reads one pixel for each cycle of the drive clock signal, and the ACIS 35 accumulates electric charges from the output signal from the image sensor 14 for each cycle. And CPU31 acquires the signal level (signal level of the peak level vicinity) in a predetermined sampling point for every period as pixel data, and changes a current supply signal so that the value may become in a predetermined range. The light amount of each color light emitting diode (lighting time of one line and supplied current value) is adjusted.

  Next, the CPU 31 drives the step motor 40 to move the image sensor 14 to a position facing the resolution measurement reference unit 22 (S105). Then, without changing the resolution setting in S103, the image sensor 14 scans the resolution measurement reference unit 22 from the black area 22A to the white area 22B to read one line (S106).

  FIG. 8 shows changes in the level of the output signal when the reading operation of the resolution measurement reference unit 22 is performed by the A-type and B-type image sensors 14. As described above, the CPU 31 acquires, as pixel data, a signal level (a signal level near the peak level) at a predetermined sampling point for each pixel based on the output signal from the image sensor 14. In this reading operation, pixel data is acquired up to a number larger than the number of pixels (approximately 10000) (up to count 10911) when reading is performed at a resolution of 1200 dpi.

  Of the obtained pixel data, the data corresponding to the actual reading of the resolution measurement reference unit 22 is effective pixel data. If the resolution is 1200 dpi, about 10,000 pixels per line, and if the resolution is 300 dpi, about 2500 pixels per line. Effective pixel data is obtained, and the rest is invalid pixel data.

  The CPU 31 compares the signal level of each pixel with a predetermined threshold value to obtain a value of H (on) or L (off). The effective pixel data takes the value of L at first (corresponding to the reading of the black area 22A) regardless of whether the resolution is set to 1200 dpi or 300 dpi, and the value of H is determined from a certain pixel position. (Corresponding to reading of the white area 22B). When the H value continues for 10 pixels or more following the L value, the CPU 31 determines that the pixel position of the first H value is the pixel position where the black region 22A and the white region 22B are switched. If the resolution is 300 dpi at the time of reading, the pixel position at which black and white switches is around 125 pixels, for example, and if the resolution is 1200 dpi, the pixel position at which black and white switches is around 500 pixels.

  The CPU 31 determines that the resolution is set to 1200 dpi when the number of pixels when the black and white are switched is a predetermined threshold, for example, 264 or more (S107: Yes). (S108), if it is less than 264 (S107: No), it is considered that the resolution is set to 300 dpi, so the image sensor 14 is determined to be the B type (S109).

  When the image sensor 14 is determined as the A type, various settings for the A type are performed (S110), and various settings for the B type are performed (S111). Specifically, for example, when the image sensor 14 is determined to be the A type, the gamma table corresponding to the A type image sensor 14 is set to be used when correcting the read data. When it is determined that the type is B, the gamma table corresponding to the type B is set to be used. Further, according to the type of the image sensor 14, the functions of the 9th to 11th signal lines (current supply signals) are switched to those corresponding to the image sensor 14 of that type.

(Effect of this embodiment)
As described above, according to the present embodiment, the resolution switching signal is input to the image sensor 14, the resolution is detected from the output signal of the image sensor 14 during the reading operation, and the type of the image sensor 14 is selected based on the resolution. As a result of the determination, simple and accurate determination is possible.

  Further, since the resolution switching signal is a time-series signal, various information can be transmitted with a small number, and the number of signal lines can be suppressed.

  Further, the resolution measurement reference unit 22 is read by the image sensor 14, the pixel position corresponding to the boundary position between the white area 22B and the black area 22A is obtained from the output signal, and the resolution of the image sensor 14 is detected based on the pixel position. By doing so, the resolution can be accurately detected by a simple method.

  Further, when the resolution of the image sensor 14 is detected, the image sensor 14 and the resolution measurement reference unit 22 are moved relative to each other so that the resolution measurement reference unit 22 does not interfere with the document reading operation. It becomes possible to arrange in.

  In addition, since the type (function) of the signal transmitted through the signal line is switched in accordance with the type of the image sensor 14, more types of image sensors can be handled.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above-described embodiment, the resolution is detected based on the pixel position corresponding to the boundary position between the white area and the black area. However, the resolution detection method is not limited to this, for example, acquired at the time of the reading operation. The resolution may be detected based on the amount of effective pixel data. Specifically, for example, the white reference portion is read for one line, and the number of pixels having a signal level equal to or higher than the reference is counted in the obtained pixel data (if the conditions are the same as those shown in FIG. 8). ) If the number of pixels is about 2500, the resolution can be calculated such that it is 300 dpi, and if it is about 10,000, it is 1200 dpi.

(2) In the above-described embodiment, the A-type and B-type image sensors have the same timing at which the output signal reaches the peak level. However, the present invention provides the peak level timing (waveform) depending on the type of the image sensor. It can also be applied to different ones. In this case, for example, when detecting the resolution of the image sensor, the signal level is acquired at a temporary sampling point, and when the reading operation is performed after the type of the image sensor is determined, it is matched with the type of the image sensor. The signal level may be acquired at the optimum sampling point.

(3) In the above embodiment, an example in which the present invention is applied to a multi-function peripheral has been shown. However, the present invention is provided with a printer function, a copy function, and a facsimile function as long as the image reading apparatus has at least a scanner function. It can also be applied to those that do not.

External perspective view of multifunction device Main section enlarged view of the document reading section Plan view of the reference member Block diagram schematically showing the electrical configuration of the MFP The figure explaining the number of the signal line which connects A type image sensor and ASIC, and the function of the signal Timing chart explaining the relationship between the resolution switching signal and the resolution setting for each type of image sensor Flow chart showing the flow of sensor discrimination processing Timing chart showing an example of the output signal of the image sensor during sensor discrimination processing

Explanation of symbols

1 ... Multifunction machine (image reading device)
22 ... Resolution measurement reference part (reference part)
31 ... CPU (discriminating means)
35 ... ASIC (input means)
40: Step motor (moving means)

Claims (7)

An image reading apparatus in which an image sensor selected from a plurality of types of image sensors capable of switching resolution based on a resolution switching signal and performing reading operations at different resolutions with respect to the same resolution switching signal Because
Input means for inputting a resolution switching signal to the image sensor;
Determining means for detecting the resolution at the time of reading operation based on an output signal from the image sensor, and determining the type of the image sensor based on the resolution;
An image reading apparatus comprising: The image reading apparatus according to claim 1,
The resolution switching signal is a time series signal composed of binary values of ON and OFF. The image reading apparatus according to claim 1 or 2,
A white area and a black area are provided with a reference portion provided adjacent to the main scanning direction of the image sensor,
The discrimination means reads the reference portion by the image sensor, obtains a pixel position corresponding to the boundary position between the white area and the black area from the output signal, and detects the resolution of the image sensor based on the pixel position. . The image reading apparatus according to claim 3.
When detecting the resolution of the image sensor, the image sensor includes a moving unit that relatively moves the image sensor and the reference unit to face each other. In the image reading device according to any one of claims 1 to 4,
The determination unit detects the resolution based on the amount of effective pixel data acquired from the output signal per unit scan of the image sensor. In the image reading device according to any one of claims 1 to 5,
The input means is connected to the image sensor by a plurality of signal lines, and is transmitted by at least some of the plurality of signal lines according to the type of the image sensor determined by the determination means. Switch the signal type. A method for discriminating the type of image sensor selected from a plurality of types of image sensors capable of switching the resolution based on the resolution switching signal and performing a reading operation at different resolutions with respect to the same resolution switching signal Because
A resolution switching signal is input to the image sensor to execute a reading operation, the resolution at the time of the reading operation is detected based on an output signal from the image sensor, and the type of the image sensor is determined based on the resolution. Image sensor discrimination method.

Images