JP5742197B2 - Image reading apparatus, image reading method, and program - Google Patents

Description

  The present invention relates to an image reading apparatus, an image reading method, and a program.

  Conventionally, as this type of image reading apparatus, light is irradiated onto an original from an illumination lamp that reciprocates in the sub-scanning direction by the rotation of a scanner motor, and the light reflected by the original and guided by a mirror or lens is detected by a CCD. There has been proposed an apparatus that generates image data by photoelectrically converting line-by-line and outputting the result to an A / D conversion circuit, and performing image correction processing on the image signal digitized by the A / D conversion circuit (for example, , See Patent Document 1). In this apparatus, when a lamp on / off control signal for turning on / off the illumination lamp is on, a high-frequency pulse corresponding to a clock synchronized with a line synchronization signal defining the read start timing of each line is used. The illumination lamp is turned on / off. The white streak in the sub-scanning direction due to lamp lighting noise is reduced by adjusting the clock rise timing with respect to the line synchronization signal so that the rise timing of the light emission of the illumination lamp does not overlap in the sub-scanning direction. .

JP 2006-211141 A

  In such an image reading apparatus, when the charge (electrical signal) for one line photoelectrically converted is sequentially output from the CCD, the timing for outputting the charge from the CCD and the timing for switching the switching element of the motor driver that drives the scanner motor If they overlap, noise due to switching of the switching element rides on the charge output from the CCD, and the generated image data may be disturbed.

  An image reading apparatus, an image reading method, and a program according to the present invention are mainly intended to suppress noise from being mixed into image data generated by reading a document.

  The image reading apparatus, the image reading method, and the program according to the present invention employ the following means in order to achieve the main object described above.

The image reading apparatus of the present invention includes:
Irradiating means for irradiating the reading object with light;
A light receiving output means for photoelectrically converting the light obtained through the reading object by each of a plurality of photoelectric conversion elements arranged in the main scanning direction and accumulating the accumulated electric charge, and sequentially outputting the accumulated electric charge;
Moving means for moving at least the irradiation means in the sub-scanning direction by rotation of a motor;
When the charges are sequentially output from the light receiving output means, an output scheduled timing that is a schedule for outputting charges from the light receiving output means and a switching timing that is a switching timing of a switching element of a drive circuit that drives the motor If they do not overlap, charge is output from the light receiving output means at the scheduled output timing, and if the scheduled output timing and the switching timing overlap, no charge is output from the light receiving output means at the scheduled output timing. An output processing means for waiting;
Image data generating means for generating image data using the output electric charge;
It is a summary to provide.

  In the image reading apparatus according to the present invention, when the charges are sequentially output from the light receiving output means, the scheduled output timing, which is the timing at which the charges are output from the light receiving output means, and the switching elements of the drive circuit for driving the motor are switched. If the switching timing, which is the timing, does not overlap, charge is output from the light receiving output means at the scheduled output timing, and if the scheduled output timing and switching timing overlap, the charge is not output from the light receiving output means at the scheduled output timing. To wait. Then, image data is generated using the charges output from the light receiving output means. Therefore, when the charge is output from the light receiving output means, it can be avoided that noise caused by switching of the switching element is added to the charge. As a result, it is possible to prevent noise from being mixed into the image data. Here, the “motor” may be a stepping motor.

  In such an image reading apparatus of the present invention, when the output processing means sequentially outputs charges from the light receiving output means during execution of the chopping control for periodically switching the switching element, the switching period in the chopping control is When the scheduled output timing and the switching timing in different second periods do not overlap, the light receiving output means outputs charges at the scheduled output timing, and when the scheduled output timing and the switching timing overlap. At the scheduled output timing, the light receiving output means may be a means for waiting without outputting charges. In this way, when charge is output from the light receiving output means during execution of the chopping control, it is possible to avoid noise caused by switching of the switching element from being applied to the charge. Here, the chopping control may be control performed while the rotation of the motor is stopped.

  In the image reading apparatus according to the aspect of the invention in which charges are sequentially output from the light receiving output unit during the execution of the chopping control, the output processing unit is a scheduled output timing which is the number of the scheduled output timing after the rotation of the motor is stopped. It is a means for determining whether the scheduled output timing and the switching timing overlap using the number of times and the number of times of switching timing that is the number of times of the switching timing after the rotation of the motor is stopped. You can also. In this way, it is possible to determine whether or not to output charges from the light receiving means using the scheduled output timing count and the switching timing count.

  In the image reading apparatus according to the aspect of the invention in which charges are sequentially output from the light reception output unit during execution of the chopping control, the switching timing is a timing at which the switching element is switched from on to off during the execution of the chopping control. There can be.

  In the image reading apparatus of the present invention, the input unit for inputting the charge output from the light receiving output unit may be formed on the same substrate as the switching element. In this case, since the noise caused by the switching of the switching element is easily applied to the charge input to the input unit, the significance of performing the processing of the present invention is great. Here, the “input unit” may be a unit that converts the electric charge output from the light receiving output unit into a digital value.

  In the image reading apparatus of the present invention, the moving unit may be a unit that moves the light receiving unit together with the irradiating unit.

The image reading method of the present invention includes:
Irradiation means for irradiating light to the reading object and light obtained through the reading object are photoelectrically converted by each of a plurality of photoelectric conversion elements arranged in the main scanning direction and accumulated as charges, and the accumulated charges are stored. An image reading method using an image reading apparatus comprising: a light receiving output means that sequentially outputs; and a moving means that moves at least the irradiation means in the sub-scanning direction by rotational driving of a motor,
(A) When charges are sequentially output from the light receiving output means, switching is a scheduled output timing that is a timing to output charges from the light receiving output means and a switching timing of a switching element of a drive circuit that drives the motor. If the timing does not overlap, the charge output means outputs the charge at the scheduled output timing. If the scheduled output timing and the switching timing overlap, the charge is output from the received light output means at the scheduled output timing. A step to wait without letting
(B) generating image data using the outputted charges;
It is made to include.

  In the image reading method of the present invention, when the charges are sequentially output from the light receiving output means, the scheduled output timing, which is the timing at which charges are scheduled to be output from the light receiving output means, and the switching of the switching element of the drive circuit that drives the motor. If the switching timing, which is the timing, does not overlap, charge is output from the light receiving output means at the scheduled output timing, and if the scheduled output timing and switching timing overlap, the charge is not output from the light receiving output means at the scheduled output timing. To wait. Then, image data is generated using the charges output from the light receiving output means. Therefore, when the charge is output from the light receiving output means, it can be avoided that noise caused by switching of the switching element is added to the charge. As a result, it is possible to prevent noise from being mixed into the image data. In this image reading method, various aspects of the above-described image reading apparatus may be adopted, and steps for realizing each function of the above-described image reading apparatus may be added.

  The program of the present invention is for causing one or more computers to realize each step of the above-described image reading method. This program may be recorded on a computer-readable recording medium (for example, hard disk, ROM, FD, CD, DVD, etc.), or from a computer via a transmission medium (communication network such as the Internet or LAN). It may be distributed to another computer, or may be exchanged in any other form. If this program is executed by one computer or if each computer executes the steps in a shared manner, each step of the above-described image reading method is executed, so that the same effect as the control method can be obtained. It is done.

FIG. 2 is a configuration diagram illustrating an outline of a configuration of a multifunction printer 20. FIG. 3 is an external view of the printer 20 in a state where a housing cover 22 is opened. FIG. 2 is a configuration diagram showing an outline of the configuration of a scanner unit 40. Explanatory drawing which shows an example of the phase current which flows into each phase of the carriage motor 78a. 6 is a flowchart illustrating an example of a document fixing reading processing routine. Explanatory drawing which shows an example of a mode that an electric charge is output from CIS74.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an outline of the configuration of a multi-function printer 20 according to an embodiment of the present invention. FIG. 2 is an external view of the multi-function printer 20 with a housing cover 22 opened. FIG. 3 is a configuration diagram showing an outline of the configuration of the scanner unit 40.

  The multi-function printer 20 according to the present embodiment includes a housing 21 and a housing cover 22 that can open and close the top surface of the housing 21, and a scanner unit 40 that optically reads a document and generates image data. A printer unit 42 that feeds, prints, and discharges paper set in the cassette 23 to the paper discharge tray 24, an operation panel 46 that allows various operations by the user, and a main unit that controls the entire apparatus. And a controller 80. A glass table 32 is disposed on the upper surface of the housing 21 (see FIG. 2), and a document placed on the glass table 32 can be optically read by the scanner unit 40 (see FIG. 2). Hereinafter, this operation mode is referred to as a document fixed reading mode). The housing cover 22 incorporates an auto document feeder unit 61 (hereinafter referred to as an ADF unit) (see FIG. 3), and the document set by the document guide 29 and set in the ADF insertion slot 26 is stored. The scanner unit 40 can optically read while continuously automatically conveying (hereinafter, this operation mode is referred to as an ADF reading mode).

  The scanner unit 40 includes a scanner ASIC 50 and a scanner engine 60. The scanner ASIC 50 is an integrated circuit that controls the scanner engine 60. Upon receiving a scan command from the main controller 80, the scanner ASIC 50 reads the document as image data in either the fixed document reading mode or the ADF reading mode. 60 is controlled. Note that ASIC is an abbreviation for Application Specific Integrated Circuit.

  As shown in FIG. 3, the scanner engine 60 includes an ADF unit 61 that automatically conveys a document set in the ADF insertion slot 26 to the ADF reading area 34, and a light source unit that irradiates light to the glass table 32 or the ADF reading area 34. 71, a contact image sensor (CIS) 74 for reading the original by receiving reflected light from the original and storing it as a charge, a carriage 76 on which the light source unit 71 and the CIS 74 are mounted, and a carriage motor configured as a stepping motor And a moving mechanism 77 that reciprocates in the sub-scanning direction of the carriage 76 by driving the belt 79 spanned between 78a and the driven roller 78b by the carriage motor 78a. The ADF unit 61 includes a pickup roller 63 disposed in the vicinity of the ADF insertion port 26, a plurality of transport rollers 64 disposed in the transport path 62, and a paper discharge roller 65 disposed in the vicinity of the ADF paper discharge tray 28. The rollers 63, 64, 65 are rotated by a conveyance motor 66 configured as a DC motor, a stepping motor, or the like, whereby the originals set in the ADF insertion port 26 are taken one by one and are conveyed on the conveyance path 62. Automatically transport to. In this embodiment, the carriage motor 78a uses a two-phase stepping motor having a rotor attached to a rotating shaft and a two-phase coil wound around a stator (not shown) (see an enlarged view in FIG. 3). The light source unit 71 has light sources of three colors, a red LED 72R that turns on red light, a green LED 72G that turns on green light, and a blue LED 72B that turns on blue light (see FIG. 2). The light is irradiated to the glass table 32 or the ADF reading area 34 through the light guide 73. The CIS 74 is configured as a plurality of imaging elements 75 arranged in the main scanning direction, and the plurality of imaging elements 75 are configured as photoelectric conversion elements corresponding to the pixels, and light when exposed is used as charges. A plurality of photodiodes 75a to be converted and accumulated, and a CCD 75b that is formed for each photodiode 75a and serves as a shift register capable of transferring charges received from the photodiode 75a (see an enlarged view in FIG. 3). When the CIS 74 receives a line shift signal as a signal for transferring the charge of the photodiode 75a to the CCD 75b from the main controller 80 via the control circuit 52 (described later) of the scanner ASIC 50, the charge of the plurality of photodiodes 75a. Is transferred to the corresponding CCD 75b, and when a pixel shift signal as a signal for outputting charges from the CIS 74 is received from the main controller 80 via the control circuit 52, other than the tip (one end) in the arrangement direction If the CCD 75b has a charge, the charge is transferred to the adjacent CCD 75b on the front end side. If the CCD 75b at the front end in the arrangement direction has a charge, the charge is transferred via an amplifier (not shown) through an amplifier (not shown). Output to. Here, a CCD image sensor is exemplified as the CIS 74, but a CMOS type image sensor may be adopted.

  The scanner ASIC 50 converts the control circuit 52 that controls each device, the LED drive circuit 54 that individually turns on / off the red LED 72R, the green LED 72G, and the blue LED 72B, and the electric charge (analog signal) output from the CIS 74 into a digital signal. An analog front end (AFE) 56, a carriage motor driving circuit 58 that drives a carriage motor 78a by switching a switching element (for example, a transistor), and a conveyance that drives a conveyance motor 66 by switching the switching element. A motor drive circuit 59. Here, each component of the scanner ASIC 50 is formed on the same substrate in this embodiment. In the present embodiment, the scanner ASIC 50 also uses the carriage motor 78a by a micro-step driving method in which the rotation angle change amount corresponding to the length of one line in the sub-scanning direction when the original is read line by line by the CIS 74 is a step angle. The switching element of the carriage motor drive circuit 58 is controlled to be driven to rotate, and is switched at a predetermined cycle (for example, 5 μsec or 10 μsec) while the rotation of the carriage motor 78a is stopped (maintaining the rotation angle). The so-called chopping control for switching the element is executed. FIG. 4 shows an example of the phase current that flows in each phase of the carriage motor 78a when the carriage motor 78a is driven in this way. When the scanner ASIC 50 executes chopping control, the timing at which the current flowing in each phase reaches a peak value (see the enlarged view in FIG. 4) (timing for switching the switching element from on to off, hereinafter referred to as chopping timing). ) Is output to the main controller 80 from a timing that is slightly earlier than the chopping timing to a timing that is slightly later than the chopping timing. In the present embodiment, for the sake of simplicity, the chopping timing when executing the chopping control is set to be the same timing in two phases.

  The printer unit 42 includes a printer ASIC 44 and a printer engine 45. The printer ASIC 44 is an integrated circuit that controls the printer engine 45. Upon receiving a print command from the main controller 80, the printer ASIC 44 controls the printer engine 45 to print an image on recording paper based on an image file that is a target of the print command. . The printer engine 45 is configured as a well-known inkjet color printer mechanism that performs printing by ejecting ink from a print head onto paper. Since the printer unit 42 does not form the gist of the present invention, further detailed description is omitted.

  The operation panel 46 includes a display unit 47 disposed in the center and a power button 48 disposed on the left side of the display unit 47. The display unit 47 is configured as a touch panel type liquid crystal display, a mode button for selecting a mode, a selection / setting button for selecting a menu or an item by touching according to a guide displayed on the display, copying or printing Display a start button or the like to start the touch and accept a touch operation. Here, as modes that can be selected by the mode selection button, printing is performed using a copy mode in which an original placed on the glass table 32 is scanned and copied, or an image stored in the memory card MC of the memory card slot 49. There are a memory card mode in which a document is scanned and converted into data and stored in the memory card MC, and a film mode in which a photographic film is scanned and printed or data is stored in the memory card MC.

  The main controller 80 is configured as a microprocessor centered on the CPU 82, and includes a ROM 84 that stores various processing programs, various data, various tables, a RAM 86 that temporarily stores scan data and print data, and an operation panel. And an internal communication interface 88 that enables communication with. The main controller 80 inputs various operation signals and various detection signals from the printer unit 42 and the scanner unit 40, and inputs operation signals generated in response to a touch operation on the operation panel 46. In addition, an image file is read from the memory card MC inserted in the memory card slot 49, a command is output to the printer unit 42 to execute printing of image data, and a document is read based on a scan command from the operation panel 46. A command is output to the scanner unit 40 to read as image data, or a control command for the display unit 47 is output to the operation panel 46.

  The multi-function printer 20 configured in this way can read the original in a color mode for reading the original in color or in a monochrome mode for reading the original in monochrome. In the color mode, the red LED 72R, the green LED 72G, and the blue LED 72B are turned on one by one while being switched one line at a time, and the reflected light is photoelectrically converted by the CIS 74 and input to the control circuit 52 via the AFE 56. Color image data is generated using (electrical signal). In the monochrome mode, the red LED 72R, the green LED 72G, and the blue LED 72B are turned on simultaneously in one line, and the reflected light is photoelectrically converted by the CIS 74 and input to the control circuit 52 via the AFE 56, and the input charge (electrical signal) ) To generate monochrome image data.

  Next, an operation of the thus configured multifunction printer 20 of the present embodiment, particularly an operation when reading a document in the document fixed reading mode will be described. FIG. 5 is a flowchart showing an example of a document fixed reading process routine executed by the main controller 80. This routine is executed when the copy mode or the memory card mode is selected by the mode selection button, and the start button is touched with the document set on the glass table 32. Hereinafter, for the sake of simplicity, the case of reading an original in the monochrome mode will be described.

  When the original fixed reading mode reading processing routine is executed, the main controller 80 first moves the carriage 76 to a position (reading start position) where the first line in the reading area of the glass table 32 can be read. An initial movement signal is output to the scanner ASIC 50 (step S100). Upon receiving the initial movement signal, the scanner ASIC 50 drives the carriage motor 78a by switching the switching element of the carriage motor drive circuit 58 so that the carriage 75 moves to the reading start position.

  Subsequently, an exposure process start signal for starting the exposure process of the first line is output to the scanner ASIC 50 (step S110), and the completion of the exposure process of the first line is waited (step S120). Considering the case of reading a document in monochrome mode, the scanner ASIC 50 that has received the exposure processing start signal turns on the red LED 72R, the green LED 72G, and the blue LED 72B simultaneously by driving the LED drive circuit 54, and reflects the reflected light. It is photoelectrically converted by a plurality of photodiodes 75a and accumulated as electric charges. At this time, the scanner ASIC 50 executes chopping control and periodically outputs a chopping timing signal as a signal indicating the chopping timing to the main controller 80.

  When the exposure processing for the first line is completed, a phase switching signal as a signal for moving the carriage 76 to a position where the next line can be read is output to the scanner ASIC 50, and the charge of the photodiode 75a is transferred to the CCD 75b. A line shift signal as a signal to be transferred to the CIS 74 is output to the CIS 74 via the scanner ASIC 50 (step S130). Upon receiving the phase switching signal, the scanner ASIC 50 switches the switching elements of the carriage motor drive circuit 58 so that the carriage 76 moves to a position where the next line can be read, that is, the carriage motor 78a rotates by the above-described step angle. The carriage motor 78a is driven by the control. The CIS 74 that has received the line shift signal transfers the charge of the photodiode 75a to the CCD 75b.

  Subsequently, the pixel shift count value C1 indicating the number of pixel shift signal generations as a signal for outputting charges from the CIS 74 and the chopping count value C2 indicating the number of chopping timings are both reset to a value 0 (step S140). ). Here, the pixel shift signal is a signal generated in the main controller 80 at a cycle (for example, every several hundreds nsec or every several μsec) different from the cycle of chopping timing (for example, 5 μsec or 10 μsec). . The pixel shift count value C1 is a count value of a pixel shift counter (not shown) that counts up every time a pixel shift signal is generated, and the chopping count value C2 is counted up every time a chopping timing signal is acquired from the scanner ASIC 50. This is the count value of a chopping counter (not shown).

  Then, it is determined whether or not the exposure processing for all the lines to be subjected to the exposure processing (up to the final line) has been completed (step S150). An exposure process start signal for starting the exposure process for the second line is output to the scanner ASIC 50 (step S160), and when the exposure process for all the lines up to the last line has been completed, the current position of the carriage 76 is reached. Therefore, the exposure process start signal is not output to the scanner ASIC 50. In the present embodiment, the time required for the exposure process is shorter than the time required for outputting charges (electrical signals) corresponding to the number of imaging elements 75 from the CIS 74.

  Next, it is determined whether or not it is the pixel shift signal generation timing as the timing at which the pixel shift signal is generated (step S170). If it is not the pixel shift generation timing, the process returns to step S170, and if it is the pixel shift generation timing. Acquires the pixel shift count value C1 and the chopping count value C2 (step S180), and the pixel shift count value C1 and the chopping count value C2 are output as timings at which charges (electrical signals) are to be output from the CIS 74. It is determined whether or not there is an overlapping relationship defined as a relationship that is expected to overlap the scheduled timing and the chopping timing (step S190). This determination is made, for example, when the period of the scheduled output timing is half of the period of the chopping timing and the first scheduled output timing after moving the carriage 76 and the first chopping timing overlap, the pixel shift count value C1. And the chopping count value C2 can be determined by whether or not the following expression (1) is satisfied.

  C1 = 2 ・ C2-1 (1)

  If the pixel shift count value C1 and the chopping count value C2 do not overlap, it is determined that the scheduled output timing and the chopping timing do not overlap, and the pixel shift signal is output to the CIS 74 via the scanner ASIC 50 ( Step S200). The CIS 74 that has received the pixel shift signal outputs the charge to the control circuit 52 via the AFE 56. Then, it is determined whether or not charges equivalent to the number of imaging elements 75 are output from the CIS 74 (step S210). If charges corresponding to the number of imaging elements 75 are not yet output from the CIS 74, the process returns to step S170.

  On the other hand, if the pixel shift count value C1 and the chopping count value C2 are in the overlapping relationship in step 190, it is determined that the scheduled output timing and the chopping timing overlap, and the pixel shift signal is not output to the CIS 74. Return to step S170. If the timing at which the charge is output from the CIS 74 and the timing of chopping overlap, noise may be added to the charge (electrical signal) output from the CIS 74, but this problem is caused by not outputting the charge from the CIS 74. It can be avoided. In this embodiment, as described above, each component of the scanner ASIC 50 is formed on the same substrate. Therefore, switching of the carriage motor drive circuit 58 to the charge input from the CIS 74 to the control circuit 52 via the AFE 56 is performed. Noise caused by switching of elements is likely to ride. For this reason, it is significant that no charge is output from the CIS 74 when the scheduled output timing and the chopping timing overlap.

  In this way, when it is determined in step S210 that charges corresponding to the number of the imaging elements 75 have been output from the CIS 74, it is determined whether or not all the lines to be read have been read (step S220). ) If all the lines have not been read yet, the process returns to step S130 to output a phase switching signal to the scanner ASIC 50 to move the carriage 76 to a position where the next line can be read and send the line shift signal to the scanner ASIC 50. To the CIS 74 to transfer the charge of the photodiode 75a to the CCD 75b. In the present embodiment, as described above, when the pixel shift count value C1 and the chopping count value C2 are in an overlapping relationship, the pixel shift signal is not output to the CIS 74 and waits. Regardless of whether or not the value C1 and the chopping count value C2 are in an overlapping relationship, the output cycle of the phase switching signal and the line shift signal is longer than that in which the pixel shift signal is output to the CIS 74. In this way, the processing of steps S130 to S220 is repeatedly executed, and if it is determined in step S220 that all lines have been read, image data is generated using the read charges (electrical signals) (step S230), and this routine is executed. Exit. Here, the generation of the image data is performed, for example, by performing shading correction on the input signal. The image data thus generated is subjected to processing selected by the user, for example, storage processing stored in the memory card MC, printing processing printed by the printer unit 42, display processing displayed on the operation panel 46, and the like. It was supposed to be.

  FIG. 6 is an explanatory diagram showing an example of how charges are output from the CIS 74 when a document is read. In this figure, the overlap between the scheduled output timing and the chopping timing occurs when the pixel shift count value C1 and the chopping count value C2 satisfy the above-described equation (1). As can be seen from the solid line in the figure, in this embodiment, after the phase switching signal or the line shift signal is turned on in a pulse, the image shift signal (generation) is turned on in a pulse, that is, the pixel shift. When the signal is generated, if the pixel shift count value C1 and the chopping count value C2 do not satisfy the above formula (1), the pixel shift signal (output) is turned on, that is, the pixel shift signal is output to the CIS 74, When the pixel shift count value C1 and the chopping count value C2 satisfy the equation (1), the pixel shift signal (output) remains off, that is, the pixel shift signal is not output to the CIS 74 and is waited. When the pixel shift signal (output) is turned on when the pixel shift count value C1 and the chopping count value C2 satisfy the expression (1) (see the dotted line in the figure), noise caused by switching of the switching element is generated from the CIS 74. There is a possibility of riding on electric charges (electrical signals). In contrast, in the present embodiment, when the pixel shift count value C1 and the chopping count value C2 satisfy Expression (1), the pixel shift signal (output) remains off (not turned on). This can be avoided. As a result, it is possible to prevent noise from being mixed into the image data generated using the charge (electric signal) input from the CIS 74 to the control circuit 52 via the AFE 56. Further, as is apparent from the figure, in the present embodiment, for example, the exposure process of the (i + 1) th line is performed while the charge of the i (i is a variable) line is being output from the CIS 74. The time required to complete the reading process for all lines can be shortened.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The light source unit 71 of this embodiment corresponds to “irradiation means”, the CIS 74 corresponds to “light reception output means”, the movement mechanism 77 corresponds to “movement means”, and step S170 of the document fixing reading processing routine of FIG. The main controller 80 that executes the processing of S210 corresponds to “output processing means”, and the main controller 80 that executes the processing of step S230 corresponds to “image data generation means”. The scanner ASIC 50 corresponds to “chopping control execution means”. In the present embodiment, an example of the image reading method of the present invention is also clarified by describing the operation of the multifunction printer 20.

  According to the multifunction printer 20 of the present embodiment described above, when the charges are sequentially output from the CIS 74, the pixel shift count value C1 that is the number of pixel shift signal generations and the chopping count value C2 that is the number of chopping timings are Are not overlapped as a relationship that is expected to overlap the scheduled output timing and the chopping timing, the charge is output from the CIS 74, and the pixel shift count value C1 and the chopping count value C2 are overlapped. In this case, the CIS 74 waits without outputting charges, and image data is generated using the charges output from the CIS 74. Therefore, noise caused by switching during chopping control is added to the charges output from the CIS 74. You can avoid getting onAs a result, it is possible to prevent noise from being mixed into the image data.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  In the embodiment described above, it is determined whether or not to output the pixel shift signal to the CIS 74 based on whether or not the pixel shift count value C1 and the chopping count value C2 are in an overlapping relationship. It may be determined whether to output the pixel shift signal to the CIS 74 by a method. For example, an overlap period that is assumed to overlap the scheduled output timing and the chopping timing is calculated using the pixel shift signal generation period and the chopping timing period, and the first overlap timing at which the scheduled output timing and the chopping timing overlap first Using the integral multiple of the overlap period, the second and subsequent overlap timings in which the scheduled output timing and the chopping timing overlap after the second are calculated, and the pixel shift signal is determined depending on whether or not the pixel shift signal generation timing is not the overlap timing. It is good also as what judges whether it outputs. Further, in the pixel shift generation timing, the pixel shift signal is determined depending on whether the chopping timing signal output from the scanner ASIC 50 is being received from a timing slightly earlier than the chopping timing to a timing slightly later than the chopping timing. It is good also as what judges whether it outputs.

  In the above-described embodiment, the timing for switching the switching element from on to off when performing chopping control is the chopping timing. However, the switching timing of the switching element (regardless of on to off and off to on) is used. It is good also as a chopping timing.

  In the above-described embodiment, when the charge is sequentially output from the CIS 74, the standby is performed without outputting the charge from the CIS 74 when the scheduled output timing and the chopping timing overlap. It is not limited to the case of overlapping, and when the scheduled output timing overlaps with the switching timing of the switching element of the carriage motor drive circuit 58, the CIS 74 may wait without outputting charges.

  In the above-described embodiment, the exposure process for the i (i is a variable) line is performed, and then the carriage motor 78a is driven to rotate and the charge of the photodiode 75a is transferred to the CCD 75b. Although the (i + 1) -th line exposure process is performed while being output, the i-th line exposure process is performed. After the completion, the charge of the photodiode 75a is transferred to the CCD 75b and sequentially output from the CIS 74, and imaged from the CIS 74. The carriage motor 78a may be driven to rotate when charges corresponding to the number of elements 75 are output.

  In the above-described embodiment, the case of reading an original in the monochrome mode has been described. However, when reading an original in the color mode, except that the original is read while the red LED 72R, the green LED 72G, and the blue LED 72B are turned on one by one. This can be considered in the same manner as when reading an original in monochrome mode.

  In the above-described embodiment, the image data is generated using the electric charges (electrical signals) read after reading all the lines. However, every time the electric charge for one pixel is read, the electric charge for one line is read. Image data may be generated every time.

  In the above-described embodiment, the red LED 72R, the green LED 72G, and the blue LED 72B are used as the light source unit 71. However, the present invention is not limited to this, and a white LED is used as the light source unit. A fluorescent lamp may be used as the light source unit, and light may be guided to the sensor by a mirror or a lens.

  In the above-described embodiment, the CIS 74 mounted on the carriage 76 together with the light source unit 71 and moving in the sub-scanning direction is used. However, a mirror mounted on the carriage 76 together with the light source unit 71 and a lens or CCD not mounted on the carriage 76. And a CCD image sensor that reads an image by transmitting light to the CCD via a mirror or a lens.

  In the embodiment described above, each component of the scanner ASIC 50 is formed on the same substrate, but may be formed on a different substrate.

  In the embodiment described above, the main controller 80 and the scanner ASIC 50 are provided. However, the function sharing is not limited to this, and the main controller 80 and the scanner ASIC 50 may be integrated, or other ASICs may be provided. It is good also as what is further provided and share functions.

  In the embodiment described above, the carriage motor 78a uses a stepping motor. However, the present invention is not limited to this. For example, a DC motor, a synchronous motor, an induction motor, or the like may be used.

  In the above-described embodiment, the multi-function printer 20 has been described. However, the present invention is not limited to this. For example, a scanner device without a printer function or a FAX device having a FAX function may be used. The printer unit 42 is an inkjet color printer mechanism, but is not limited thereto, and may be an electrophotographic color printer, a dot impact color printer, or a monochrome printer of these. Good.

  In the above-described embodiment, the multi-function printer 20 has been described. However, an image reading method or a program for executing this method may be used.

  20 Multi-function printer, 21 housing, 22 housing cover, 23 cassette, 24 paper discharge tray, 26 ADF insertion slot, 28 ADF paper discharge tray, 29 document guide, 32 glass stand, 34 ADF reading area, 40 scanner unit, 42 Printer unit, 44 Printer ASIC, 45 Printer engine, 46 Operation panel, 47 Display unit, 48 Power button, 49 Memory card slot, 50 Scanner ASIC, 52 Control circuit, 54 LED drive circuit, 56 AFE, 58 Carriage motor drive circuit , 59 Conveyance motor drive circuit, 60 Scanner engine, 61 Auto document feeder (ADF) unit, 62 Conveyance path, 63 Pickup roller, 64 Conveyance roller, 65 Discharge low 71, light source unit, 72R, 72G, 72B LED, 73 light guide, 74 CIS, 75 light receiving element, 76 carriage, 78a carriage motor, 78b driven roller, 79 belt, 80 main controller, 82 CPU, 84 ROM, 86 RAM, 88 interface (I / F), MC memory card, S Original.

Claims (8)

Irradiating means for irradiating the reading object with light;
A light receiving output means for photoelectrically converting the light obtained through the reading object by each of a plurality of photoelectric conversion elements arranged in the main scanning direction and accumulating the accumulated electric charge, and sequentially outputting the accumulated electric charge;
Moving means for moving at least the irradiation means in the sub-scanning direction by rotation of a motor;
When the charges are sequentially output from the light receiving output means, an output scheduled timing that is a schedule for outputting charges from the light receiving output means and a switching timing that is a switching timing of a switching element of a drive circuit that drives the motor If they do not overlap, charge is output from the light receiving output means at the scheduled output timing, and if the scheduled output timing and the switching timing overlap, no charge is output from the light receiving output means at the scheduled output timing. An output processing means for waiting;
Image data generating means for generating image data using the output electric charge;
An image reading apparatus comprising: The image reading apparatus according to claim 1,
When the output processing means sequentially outputs charges from the light receiving output means during execution of the chopping control for periodically switching the switching element, the output processing means has a second cycle different from the switching cycle in the chopping control. When the timing does not overlap with the switching timing, the light receiving output means outputs the charge at the scheduled output timing, and when the scheduled output timing and the switching timing overlap, the received light output means at the scheduled output timing. It is a means to wait without outputting charge from,
Image reading device. The image reading apparatus according to claim 2,
The output processing means uses the scheduled output timing number that is the number of scheduled output timings after the rotation of the motor is stopped and the switching timing number that is the number of switching timings after the motor stops rotating. A means for determining whether or not the scheduled output timing and the switching timing overlap.
Image reading device. The image reading apparatus according to claim 2, wherein
The switching timing is a timing of switching the switching element from on to off during execution of the chopping control.
Image reading device. An image reading apparatus according to any one of claims 1 to 4,
An input part for inputting the charge output from the light receiving output means is formed on the same substrate as the switching element,
Image reading device. An image reading apparatus according to any one of claims 1 to 5,
The moving means is means for moving the light receiving means together with the irradiation means.
Image reading device. Irradiation means for irradiating light to the reading object and light obtained via the reading object are photoelectrically converted by each of a plurality of photoelectric conversion elements arranged in the main scanning direction and accumulated as charges, and the accumulated charges are stored. An image reading method using an image reading apparatus comprising: a light receiving output means that sequentially outputs; and a moving means that moves at least the irradiation means in the sub-scanning direction by rotational driving of a motor,
(A) When charges are sequentially output from the light receiving output means, switching is a scheduled output timing that is a timing at which charges are expected to be output from the light receiving output means and a switching timing of a switching element of a drive circuit that drives the motor. If the timing does not overlap, the charge output means outputs the charge at the scheduled output timing. If the scheduled output timing and the switching timing overlap, the charge is output from the received light output means at the scheduled output timing. A step to wait without letting
(B) generating image data using the outputted charges;
An image reading method including:   A program for causing one or more computers to execute each step of the image reading method according to claim 7.

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