JP5574541B2 - Data transmission apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a data transmission apparatus that transmits image data while removing noise, and an image forming apparatus such as a copier, a multifunction peripheral, and a FAX apparatus including the data transmission apparatus.

  For example, an image reading unit (scanner) that reads an original and generates image data may be provided in an image forming apparatus such as a copier, a multifunction peripheral, or a FAX apparatus. Then, image data is transmitted from a portion that generates image data such as an image reading unit to a portion that performs processing (for example, image processing or printing) based on the image data. In transmission of this image data, there is a case where transmission is performed while synchronizing between the transmission unit and the reception unit from the viewpoint of preventing a timing shift or the like. An example of a technique related to synchronization in image data transmission is described in Patent Document 1.

  Specifically, in Patent Document 1, a horizontal sync signal pulse width time in a signal is compared with a pulse width time such as an unnecessary pulse, and a pulse signal is generated when the pulse width time is longer than the pulse width of the horizontal sync signal. When the pulse width time is shorter than the pulse width time of the horizontal synchronization signal, a pulse signal is generated based on the first noise removing unit that does not output the signal and the signal from the first noise removing unit. The second noise removing unit that compares the signal with the horizontal synchronizing signal and outputs a pulse signal in a fixed case, and the horizontal synchronizing signal that regenerates the horizontal synchronizing signal based on the signal from the second noise removing unit A noise pulse removal circuit configured with a reproduction unit is described. With this configuration, unnecessary signals are removed, pulses equivalent to those of the normal horizontal synchronization signal are reproduced, and horizontal synchronization is attempted to be stabilized (Patent Document 1: Claim 1, [Problem to be Solved by the Invention] ] Column etc.).

Japanese Patent Laid-Open No. 04-180365

  First, in order to synchronize the transmission unit and the reception unit in image data transmission, in addition to signals such as a horizontal synchronization signal and a vertical synchronization signal, it indicates whether the transmission of image data is a valid section or an invalid section. The valid section signal may be transmitted from the transmission unit to the reception unit. The receiving unit captures image data when the effective interval signal is in a state indicating an effective interval (for example, High or Low). In other words, the valid section signal is a signal for transmitting the start and end of image data transmission to the receiving unit.

  On the other hand, noise may be mixed in the valid interval signal, the vertical synchronization signal, and the horizontal synchronization signal. Noise may prevent accurate synchronization, which may hinder transmission of image data. Therefore, a part (for example, a noise removal circuit) that performs noise removal processing mixed in the valid section signal or the like may be provided. An effective interval signal or the like is input to the noise processing unit. Then, the noise processing unit outputs the effective interval signal after noise removal and the like to the receiving unit.

  Here, when the state of the signal from the transmission unit changes, the signal state from the transmission unit (high or low) is sampled over a certain time, and noise processing is performed. Sometimes. Specifically, if the same state does not continue for a plurality of times, it is treated as noise, and the state of the signal output to the receiving unit is maintained in the state before the change to perform noise removal. On the other hand, if the state after the change continues multiple times, it is determined that the state is not changed due to noise, and the state of the signal output to the receiving unit is changed. In some cases, noise such as an effective interval signal is removed by such a method.

  However, when noise removal is performed by such a method, there is a problem that a change point (an edge indicating start or end) of an effective interval signal input to the reception unit may be greatly delayed from the original position. Specifically, when noise is mixed in the effective interval signal from the transmission unit at a timing close to the start or end of the effective interval, the noise processing unit takes a certain time to determine whether it is noise or not. Times, the state of the signal from the transmitter is sampled. Then, during this multiple sampling, there is a case where the effective interval signal from the transmission unit changes properly instead of noise. In this case, after a plurality of samplings due to a state change due to noise are completed, a plurality of samplings are performed for a valid change in the valid interval signal. Therefore, the state change of the effective section signal output from the noise processing unit to the receiving unit is delayed.

  As described above, when the state change of the effective section signal is delayed due to noise, there is a problem that the receiving unit cannot appropriately receive the image data transmitted by the transmitting unit. For example, some of the pixels in the image data may be lost, resulting in an abnormal image.

  In the invention described in Patent Document 1, unnecessary signals are removed and a pulse equivalent to a normal horizontal synchronization signal is reproduced. However, there is no mention of the problem that the reception section cannot properly receive image data due to the shift of the effective section indicated by the effective section signal due to noise removal, and the above problem cannot be solved.

  In view of the above-described problems of the prior art, the present invention is directed to a receiving unit that is caused by noise removal by multiple samplings in order to cope with a problem that the receiving unit cannot properly receive image data due to a shift in the effective interval. It is an object of the present invention to detect the shift of the change point of the effective interval signal.

  In order to achieve the above object, a data transmission device according to claim 1 is in a state with image data, a first valid interval signal indicating whether the image data is valid or invalid, and a cycle of a predetermined line. Changes, and receives the input of the image data, the effective interval signal, and the synchronization signal, and outputs the image data and the synchronization signal, and the first data When the state of the effective interval signal changes, the state of the first effective interval signal is sampled a predetermined number of times, and when the same state continues for a predetermined number of times, the logic is switched to the continued state, and the first A noise processing unit that generates and outputs a second effective interval signal from which noise has been removed from the effective interval signal, the image data, the synchronization signal, and the second effective interval signal output by the noise processing unit A reception unit that recognizes whether the image data is an effective interval based on the second effective interval signal, and acquires the image data of the effective interval, and the noise processing unit includes: The time from the change point of the synchronization signal to the change point of the second effective interval signal is measured for a plurality of lines, a reference value is obtained based on the measured time, and the first value is calculated from the reference value and the change point of the synchronization signal. The time until the change point of the two effective interval signals is compared for each line, and the presence or absence of a shift in the effective interval due to noise mixing in the first effective interval signal is detected.

  According to this configuration, the noise processing unit measures the time from the change point of the synchronization signal to the change point of the second effective interval signal for a plurality of lines, obtains the reference value based on the measured time, and synchronizes with the reference value. The time from the change point of the signal to the change point of the second effective interval signal is compared in each line, and the presence or absence of a shift in the effective interval due to noise mixing in the first effective interval signal is detected. As a result, it is possible to detect a line in which a shift occurs in the effective section indicated by the second effective section signal by the process of removing noise generated at a timing close to the changing point of the first effective section signal.

  According to a second aspect of the present invention, in the first aspect of the invention, the noise processing unit includes a second effective interval signal indicating that the interval is effective from a change point of the synchronization signal for a plurality of lines. The time until the first change point is measured, a first reference value is obtained based on the measured time, and the first reference value is a time difference from the change point of the synchronization signal of each line to the first change point. Whether or not there is a delay in the start of the effective section is detected based on whether or not the first time difference falls within a predetermined allowable range.

  According to this configuration, the noise processing unit measures the time from the change point of the synchronization signal to the first change point of the second effective interval signal indicating that the interval has become effective for a plurality of lines, and the measured time The first reference value is obtained based on the first reference value and whether or not the first time difference, which is the time difference from the change point of the synchronization signal of each line to the first change point, falls within a predetermined allowable range. Detects whether there is a delay in the start of the valid section. As a result, it is possible to detect the occurrence of a shift (delay) at the time point when the second effective interval signal becomes valid (the start point of the effective interval).

  According to a third aspect of the present invention, in the second aspect of the present invention, the noise processing unit includes a line memory for storing line image data, and a blank data is detected for a line in which a delay in the start of the effective section is detected. The image data of the previous line or the image data of the current line shifted by the first time difference is output as image data to the receiving unit, and the line that does not detect the delay of the start of the effective section, The image data transmitted by the transmission unit is input to the reception unit.

  According to this configuration, the noise processing unit includes the line memory that stores the image data of the line, and the blank data, the image data of the previous line, or the first time is detected for the line in which the delay of the start of the effective section is detected. Any of the image data of the current line shifted by the difference is output as image data to the receiving unit, and the image data transmitted by the transmitting unit is input to the receiving unit for a line that does not detect the delay of the start of the effective section. As a result, even if the change point indicating the start of the effective interval is shifted in the second effective interval signal due to noise and the start of image data acquisition in the receiving unit is delayed, the content of the image data in the shifted line can be corrected. . Even if the start of the effective section is shifted, the influence on the image quality can be reduced.

  According to a fourth aspect of the present invention, in the invention of the second or third aspect, the noise processing unit lengthens the first time difference and the effective interval in a line where a delay in the start of the effective interval is detected. The second effective interval signal is output to the receiving unit.

  According to this configuration, the noise processing unit outputs, to the receiving unit, the second effective interval signal in which the effective interval is longer than the first time difference and the first effective interval signal in the line where the start of the effective interval is detected. To do. As a result, the effective interval that has become shorter with the delay of the start of the effective interval in the second effective interval signal is returned to the normal effective interval length, and the receiving unit acquires all the data for one line. be able to.

  Further, the invention according to claim 5 is the invention according to claim 3 or 4, wherein the blank data, the image data of the previous line, or the first time difference with respect to the line in which the delay of the start of the effective section is detected. An input unit that accepts selection of which image data of the shifted current line is to be output to the receiving unit as image data, wherein the noise processing unit is responsive to a selection input to the input unit In the line where the start delay of the section is detected, the blank data, the image data of the previous line, or the image data of the current line shifted by the first time difference is output as the image data to the receiving unit. .

  According to this configuration, the noise processing unit shifts the blank data, the image data of the previous line, or the first time difference in the line in which the delay of the start of the effective section is detected according to the selection input to the input unit. The image data of the current line is output to the receiving unit as image data. As a result, the user can select a method for correcting the content of the image data in a line whose effective section is shifted due to noise. Therefore, the user can correct the image data on the line whose effective section is shifted by an arbitrary correction method.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the input unit is configured to input an input for determining a type of image data transmitted from the transmission unit, blank data according to the type of the image data, Of the current line or the current line of image data shifted by the first time difference is received, and the noise processing unit is configured to receive the input that determines which image data is output to the receiving unit. According to the type of the image data, blank data, previous line image data, or current line image data shifted by the first time difference is used as the image data in the line where the start delay of the section is detected. Output to the receiver.

  According to this configuration, the noise processing unit is a line in which a delay in the start of the effective interval is detected, and according to the type of image data, the blank data, the image data of the previous line, or the current time shifted by the first time difference The line image data is output to the receiving unit as image data. Thereby, for example, in the image data of the document, correction is made with the data of the previous line or the current line shifted by the first time difference, and the deterioration of the image quality due to the disturbance of the outline of the character is reduced. In the image data, it is possible to perform a desired correction according to the type of the image data on the line in which the noise is generated, such as reducing the deterioration of the image quality with the blank data.

  According to a seventh aspect of the present invention, in the first to sixth aspects of the invention, the noise processing unit is configured to display the second effective section indicating that the section has become invalid from the change point of the synchronization signal for a plurality of lines. The time until the second change point of the signal is measured, a second reference value is obtained based on the measured time, and the second reference value and the time difference from the change point of the synchronization signal of each line to the second change point Whether or not there is a delay in the end of the effective section is detected based on whether or not a second time difference falls within a predetermined allowable range.

  According to this configuration, the noise processing unit measures the time from the change point of the synchronization signal to the second change point of the second effective interval signal indicating that the interval is invalid for a plurality of lines, and the measured time Based on the second reference value, the second reference value and the second time difference, which is the time difference from the change point of the synchronization signal of each line to the second change point, is effective depending on whether or not it falls within a predetermined allowable range. Detects whether there is a delay in the end of the section. As a result, it is possible to detect the occurrence of a shift (delay) at the time when the second valid section signal becomes invalid (end time of the valid section).

  The invention according to claim 8 is the invention according to claim 7, wherein the noise processing unit invalidates the effective section after the second reference value in a line in which a delay in the end of the effective section is detected. The state of the second effective interval signal is changed so as to be the interval.

  According to this configuration, the noise processing unit detects any one of the blank data and the image data of the previous line in the effective section of the line in which the delay of the end of the effective section is detected, in the effective section after the second reference value. Is output to the receiving unit as image data. As a result, even if the change point of the second effective interval signal indicating the end of the effective interval is shifted due to noise and the completion of image data acquisition in the receiving unit is delayed, the influence on the content of the image data in the shifted line is reduced. be able to.

  An image forming apparatus according to a ninth aspect includes the data transmission apparatus according to any one of the first to eighth aspects.

  According to this configuration, it is possible to provide an image forming apparatus capable of detecting a shift in an effective section due to noise mixing in a signal used for synchronization of image data transmission. In addition, since printing can be performed based on image data in which the influence on the image quality is reduced, an image forming apparatus with high-quality printed matter can be provided.

  As described above, according to the present invention, it is possible to detect the shift of the change point in the second effective interval signal with respect to the receiving unit caused by the noise removal processing by sampling. Then, it is possible to cope with a problem that the receiving unit cannot properly receive the image data due to the shift of the effective section.

1 is a schematic front cross-sectional view illustrating an example of a multifunction machine. 1 is a block diagram illustrating an example of a configuration of a multifunction machine. It is a block diagram which shows an example of the hardware regarding image data generation and transmission. It is a block diagram which shows an example of the hardware constitutions of a data transmission apparatus. It is a timing chart which shows an example of a state change of each signal when there is no noise in a data transmission device. 6 is a timing chart for explaining a delay in the start of an effective section due to noise mixing in the data transmission apparatus. It is a flowchart which shows an example of the flow of detection control of the start delay of the effective area by noise mixing. It is a flowchart which shows an example of the flow of a process at the time of the delay detection of the start of an effective area. It is explanatory drawing which shows an example of the setting screen for performing the setting of the correction | amendment of image data transmission when the delay of the start of an effective area is detected. 6 is a timing chart for explaining a delay in the start of an effective section due to noise mixing in the data transmission apparatus. It is a flowchart which shows an example of the flow of detection control of the delay of the end of the effective area by noise mixing.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In this description, a multifunction peripheral 101 (corresponding to an image forming apparatus) including the data transmission apparatus 100 will be described as an example. However, each element such as the configuration and arrangement described in the present embodiment does not limit the scope of the invention and is merely an illustrative example.

(Outline of image forming apparatus)
First, an outline of a multifunction peripheral 101 as an image forming apparatus according to the embodiment will be described with reference to FIG. FIG. 1 is a schematic front cross-sectional view illustrating an example of the multifunction machine 101.

  As shown in FIG. 1, the multifunction machine 101 of this embodiment has a document cover 101a at the top. Further, the main body of the multifunction machine 101 is provided with an operation panel 1 (corresponding to an input unit), an image reading unit 2, a paper feeding unit 3a, a conveyance path 3b, an image forming unit 4a, a fixing unit 4b, and the like.

  First, as indicated by a broken line in FIG. 1, the operation panel 1 is provided above the front surface of the multifunction machine 101. The operation panel 1 includes a liquid crystal display unit 11 that displays the state of the multifunction machine 101 and various messages. The liquid crystal display unit 11 can display one or a plurality of keys for performing function selection, setting, character input, and the like. The liquid crystal display unit 11 displays various messages. In addition, a touch panel unit 12 (for example, a resistive film type) is provided for the liquid crystal display unit 11. The touch panel unit 12 outputs a signal corresponding to the position pressed on the liquid crystal display unit 11. The operation panel 1 is also provided with various hard keys such as a start key 13 for instructing start of execution of various functions such as copying.

  The document cover 101a has a fulcrum in the depth direction in FIG. 1, and can be opened and closed in the vertical direction so as to swing the front side. The document cover 101a presses the document placed on the placement reading contact glass 21 when the document is copied.

  The image reading unit 2 reads a document placed on the placement reading contact glass 21 and forms image data of the document. In the image reading unit 2, there are optical members such as an exposure lamp 23 (see FIG. 3), an image sensor 24 (for example, CCD, see FIG. 3), a mirror (not shown), and a lens (not shown). Provided. Instead of the document cover 101a, a document conveying device that automatically and continuously conveys documents one by one toward the reading position of the image reading unit 2 (feed reading contact glass 22) may be provided. .

  Then, using these optical system members, the image reading unit 2 irradiates the document placed on the placement reading contact glass 21 with light and receives the reflected light of the document of each pixel of the image sensor 24. The output value is A / D converted to generate image data. The multi-function peripheral 101 can perform printing based on image data obtained by reading (copy function). Further, the multifunction machine 101 can transmit image data obtained by reading to the computer 200, the FAX apparatus 300, and the like (see FIG. 2, scan function, transmission function).

  The paper feed unit 3a stores a plurality of sheets (for example, various sheets such as copy sheets, plain sheets, recycled sheets, thick sheets, and OHP sheets) and sends them one by one to the conveyance path 3b. The paper feeding unit 3a includes a cassette 30 on which stored paper is placed (in FIG. 1, reference numerals 30a are assigned to the upper one and 30b are given to the lower one). In addition, paper feed rollers 31 and 32 that are rotationally driven to feed paper from the cassette 30 to the conveyance path 3b are provided (in FIG. 1, the upper one is the paper feed roller 31 and the lower one is the paper feed roller 32). For example, at the time of printing, one of the paper feed rollers 31 and 32 is rotationally driven. As a result, the sheets are sent one by one to the conveyance path 3b.

  The transport path 3b is a path for transporting paper from the paper feed unit 3a to the discharge tray 33. An image forming unit 4a, a fixing unit 4b, and the like are arranged on the sheet conveyance path. In the conveyance path 3b, a guide 34 for guiding the paper, a pair of conveyance rollers 35 that are rotationally driven during the conveyance of the sheet, and the conveyed sheet are made to wait in front of the image forming unit 4a, and the toner image A registration roller pair 36 that feeds the paper in accordance with the formation timing, a discharge roller pair 37 that discharges the paper to the discharge tray 33, and the like are provided.

  The image forming unit 4a forms a toner image based on the image data, and transfers the toner image to the conveyed paper. Therefore, the image forming unit 4a includes a photosensitive drum 41 supported so as to be rotationally driven in the direction of the arrow shown in FIG. 1, and a charging device 42, an exposure device 43, and a developing unit disposed around the photosensitive drum 41. A device 44, a transfer roller 45, a cleaning device 46 and the like are provided.

  The toner image formation and transfer process will be described. First, the photosensitive drum 41 is provided at the approximate center of the image forming unit 4a and is driven to rotate in a predetermined direction. The charging device 42 charges the photosensitive drum 41 to a predetermined potential. The exposure device 43 outputs laser light based on the image data, and scans and exposes the surface of the photosensitive drum 41. As a result, an electrostatic latent image corresponding to the image data is formed on the peripheral surface of the photosensitive drum 41. Note that as the image data, image data obtained by the image reading unit 2, image data transmitted from an external computer 200 or a partner FAX apparatus 300 (see FIG. 3) connected via a network, or the like is used.

  The developing device 44 supplies toner to the electrostatic latent image formed on the photosensitive drum 41 and develops it. The transfer roller 45 is in pressure contact with the photosensitive drum 41. Then, the registration roller pair 36 moves the paper into the nip between the photosensitive drum 41 and the transfer roller 45 at a timing in accordance with the toner image. A predetermined voltage is applied to the transfer roller 45 when the sheet enters the nip. As a result, the toner image on the photosensitive drum 41 is transferred to the sheet. The cleaning device 46 removes the toner remaining on the photosensitive drum 41 after the transfer.

  The fixing unit 4b fixes the toner image transferred to the paper. The fixing unit 4b of the present embodiment includes a heating roller 47 and a pressure roller 48 that incorporate a heating element. The heating roller 47 and the pressure roller 48 are pressed to form a nip. Then, as the sheet passes through the nip, the toner on the sheet surface is melted and heated, and the toner image is fixed on the sheet. The paper after toner fixing is discharged to the discharge tray 33. In this way, image formation (printing) is performed when the copy function and the printer function are used.

(Hardware configuration of image forming apparatus)
Next, an example of a hardware configuration of the multifunction machine 101 according to the embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating an example of the configuration of the multifunction machine 101.

  First, the main controller 5 is provided in the multifunction machine 101. The main control unit 5 controls the operation of the multifunction machine 101. The main control unit 5 includes, for example, a CPU 51 for control. The CPU 51 is a central processing unit and controls each unit of the multifunction machine 101 based on programs and data stored in the storage unit 6 and developed.

  The multifunction machine 101 is provided with an image processing unit 52. The image processing unit 52 performs various types of image processing on image data to be printed and image data to be transmitted to the external computer 200 or the counterpart FAX apparatus 300. For example, the image processing unit 52 can perform a wide variety of image processing such as density conversion, enlargement / reduction, compression / decompression, and format conversion of image data in accordance with the purpose of use, according to functions provided in the multifunction machine 101.

  The storage unit 6 includes, for example, a ROM 61 (Read Only Memory, for example, a flash ROM), a RAM 62 (Random Access Memory), and an HDD 63 (Hard Disk Drive). Thus, the memory | storage part 6 is comprised combining a non-volatile and volatile memory | storage device.

  The storage unit 6 stores various types of data such as various programs and data for controlling the multifunction peripheral 101, setting data, image data, and the like. For example, image data before and after processing by the image processing unit 52 is stored in the RAM 62 and the HDD 63 of the storage unit 6, and the image data is used for printing and transmission.

  The main control unit 5 is connected to the operation panel 1 and the image reading unit 2 through a bus, a signal line, and the like, and controls the operation of the operation panel 1 and the image reading unit 2. Further, the main control unit 5 recognizes the input content made on the operation panel 1.

  The main control unit 5 is communicably connected to the engine control unit 40. The engine control unit 40 controls the operation of a portion that performs printing (print engine portion). Specifically, the engine control unit 40 controls operations of print engine parts such as the paper feed unit 3a, the conveyance path 3b, the image forming unit 4a, and the fixing unit 4b. When executing a print job, the engine control unit 40 actually controls printing by controlling a motor that rotates various rotating bodies for paper conveyance and the like, a circuit and a part that form a toner image, and the like. The main control unit 5 instructs the engine control unit 40 to perform printing. In response to this instruction, the engine control unit 40 controls the operation of the print engine portion to perform printing.

  Further, the main control unit 5 is connected to a communication unit 53 including various connectors, sockets, a communication control chip, and the like. The communication unit 53 connects the external computer 200 and the other party's FAX apparatus 300 to the multifunction machine 101 so as to communicate with each other via a network, a public line, or the like. For example, data including image data can be transmitted to an external computer 200 or a partner FAX apparatus 300 (which may be an Internet FAX) (scanner function, FAX function). Also, printing can be performed based on image data from the external computer 200 or the counterpart FAX apparatus 300 (printer function, FAX function). As described above, the multifunction machine 101 includes a plurality of functions such as a copy function, a printer function, a scan function, and a FAX function.

(Overview of hardware configuration for image data generation and transmission)
Next, an example of image data generation and transmission in the MFP 101 according to the embodiment will be described with reference to FIG. FIG. 3 is a block diagram illustrating an example of hardware related to image data generation and transmission. Note that the flow of image data is indicated by white arrows.

  First, for example, a reading control unit 20 is provided in the image reading unit 2 that reads a document and generates image data. For example, the reading control unit 20 includes a board on which various electronic components such as a scanner CPU 20a and a memory for storing reading control programs and data are mounted. The reading control unit 20 is communicably connected to the main control unit 5. When the operation panel 1 instructs the start of copying or the start of scanning to read a document, the reading control unit 20 receives instructions from the main control unit 5 and actually controls each unit in the image reading unit 2.

  The reading control unit 20 is connected to the winding motor 2M, the lamp 23, the image sensor 24, and the like. The reading control unit 20 controls, for example, the operation of the winding motor 2M for moving the lamp 23 and various mirrors, turning on / off the lamp 23 that irradiates light on the document, driving of the image sensor 24, and the like.

  First, in reading a document and generating image data by the image reading unit 2, the image sensor 24 outputs a current (voltage) corresponding to the intensity of reflected light emitted from the lamp 23 and reflected by the document or the like for each pixel. To do. Note that the image sensor 24 of the present embodiment can output a signal indicating the luminance of each pixel in response to reading in black and white (grayscale). The image sensor 24 is a color-compatible line sensor, and can output R, G, and B signals. Each output current (voltage) of the image sensor 24 is input to the A / D converter 25. An amplifier that amplifies the output value of each pixel of the image sensor 24 may be provided before the A / D conversion unit 25.

  For example, the A / D converter 25 converts each analog output current (voltage) of each pixel of the image sensor 24 into digital image data. For example, the A / D conversion unit 25 quantizes to 8 bits to 10 bits per pixel in gray scale. Further, the A / D converter 25 quantizes R, G, and B to 8 bits to 10 bits for each pixel (for example, Red, Green, and Blue each take 8 bits and take values of 0 to 255, respectively). 256 gradations). In this way, color or gray scale image data is generated and becomes a transmission target.

  The correction unit 26 includes an arithmetic circuit for correcting the reading characteristics of the image reading unit 2 such as γ correction and shading correction. In general, in the image sensor 24, in the main scanning direction, due to variations (individual characteristic differences) of light receiving elements corresponding to pixels arranged in a line, unevenness in light emission amount due to the position of the lamp 23, lens characteristics, and the like. Even when reading the same density, a difference occurs in the value of the current (voltage) output from each light receiving element of the image sensor 24 depending on the position of the pixel. Therefore, the correction unit 26 corrects the image data output from the A / D conversion unit 25. Note that the correction processing may be performed by the image processing unit 52 described later without providing the correction unit 26.

  Then, the image data is output from the transmission unit 7 of the image reading unit 2 toward the reception unit 9 of the image processing unit 52. The image processing unit 52 performs image processing on the image data received by the receiving unit 9. For example, the image processing unit 52 performs various types of image processing such as density conversion processing, enlargement / reduction processing, rotation processing, compression / expansion processing, and data format conversion processing for printing and transmission. For this image processing, the image processing unit 52 is provided with one or a plurality of image processing circuits 52c (for example, ASIC). In FIG. 3, only one image processing circuit 52c is shown for convenience. Further, since the image processing performed by the image processing unit 52 is diverse, a detailed description is omitted assuming that known image processing can be performed.

  A noise processing unit 8 is provided between the transmission unit 7 and the reception unit 9. The transmission unit 7, the reception unit 9, and the noise processing unit 8 constitute a data transmission device 100. As described above, the multi-function peripheral 101 includes the data transmission apparatus 100.

  In this description, an example in which the receiving unit 9 is provided in the image processing unit 52 will be described, but the receiving unit 9 may be provided in the storage unit 6. In this case, the data transmission apparatus 100 handles transmission of image data from the image reading unit 2 to the storage unit 6, and image data obtained by reading the original in the image reading unit 2 is temporarily stored in the storage unit 6. The image processing unit 52 is provided. Therefore, the transmission unit 7 may be provided in the storage unit 6, the reception unit 9 may be provided separately in the image processing unit 52, and the data transmission apparatus 100 may handle transmission of image data from the storage unit 6 to the image processing unit 52. . The following description can be similarly applied to the case where the transmission unit 7 is provided other than the image reading unit 2 and the case where the reception unit 9 is provided other than the image processing unit 52.

(Hardware configuration of data transmission apparatus 100)
Next, an example of the hardware configuration of the data transmission apparatus 100 according to the embodiment will be described with reference to FIG. FIG. 4 is a block diagram illustrating an example of a hardware configuration of the data transmission apparatus 100.

  First, the transmission unit 7 will be described. The data transmission apparatus 100 includes a first timing controller 70, a first image data memory 71, and the like as a transmission circuit in the transmission unit 7.

  For example, the first timing controller 70 receives an instruction from the scanner CPU 20a at the time of copying or scanning, and generates a signal for synchronization in transmission of image data. For example, the first timing controller 70 generates a first vertical synchronization signal VSYNC1, a first horizontal synchronization signal HSYNC1, and a first valid interval signal S1.

  The first vertical synchronization signal VSYNC1 is a signal whose state changes (for example, rises) before starting transmission of image data of one page and whose state changes (for example, falls) after the end of transmission. The rise and fall may be reversed. In other words, the first vertical synchronization signal VSYNC1 is a signal indicating a break of one page of image data.

  The first image data memory 71 receives and stores input of image data generated by the image sensor 24 and digitized by the A / D conversion unit 25 and the correction unit 26. For example, the first timing controller 70 changes the first vertical synchronization signal VSYNC1 when the accumulation of the image data in the first image data memory 71 is started or when the accumulation is completed. Then, the first timing controller 70 causes the first image data memory 71 to start transmitting image data from the first line of one page of image data.

  The first horizontal synchronization signal HSYNC1 is a signal indicating a break of one line in one page of image data. The state of the first horizontal synchronization signal HSYNC1 changes before the transmission of line image data starts (for example, falls), and changes after the transmission of image data for one line ends (for example, Signal). The rise and fall may be reversed. In other words, the first horizontal synchronization signal HSYNC1 is a signal indicating a period during which image data for one line is to be transmitted.

  For example, when the storage and transmission preparation of one line of image data is completed in the first image data memory 71, the first timing controller 70 switches the line by the first horizontal synchronization signal HSYNC1, and then the first image data memory 71. To start transmission from the first pixel of one line. Thereby, data for one line is transmitted from the transmission unit 7 to the reception unit 9.

  The image data is configured by combining a plurality of lines in which a plurality of pixels are arranged in a line. Taking image data corresponding to A4 size at 600 dpi as an example, about 5000 lines are arranged on the short side of the image data (about 21 cm in the case of A4). Therefore, for example, the first horizontal synchronization signal HSYNC1 repeats rising and falling several thousand times until the first vertical synchronization signal VSYNC1 rises and falls.

  The first valid section signal S1 is a signal indicating whether or not image data transmission is in a valid state (data is valid or invalid). The first timing controller 70 changes the state of the first effective section signal S1 (for example, starts up) with the start of transmission of image data for one line from the first image data memory 71, and changes the state with the end of transmission. (E.g., fall). The rise and fall may be reversed. The state of the first valid interval signal S1 changes when the first horizontal synchronization signal HSYNC1 is falling.

  The first vertical synchronization signal VSYNC1, the first horizontal synchronization signal HSYNC1, the first effective interval signal S1, and the image data transmitted by the transmission unit 7 are input to the noise processing unit 8.

  The noise processing unit 8 is, for example, a chip ASIC. The noise processing unit 8 includes a noise removal unit 80 that removes noise from the input first vertical synchronization signal VSYNC1, first horizontal synchronization signal HSYNC1, and first effective interval signal S1.

  The noise removal unit 80 includes, for example, a noise removal control unit 82 that performs noise removal processing control, a sampling unit 83 that samples the state of each signal for noise removal processing, and a reference for detecting whether noise has occurred. A reference value holding unit 84 that holds values, a time measuring unit 85 that measures time, and the like are included.

  When there is a change in the state of each signal (first vertical synchronization signal VSYNC1, first horizontal synchronization signal HSYNC1, first effective interval signal S1), the sampling unit 83 of the noise removal unit 80 determines a predetermined number of times (for example, (Several to a dozen times), the state of the signal whose state has changed is sampled. Then, if the sampling values obtained by sampling all match with the value after the state change, the noise removing unit 80 determines that the logic of each sampled signal has been changed so far, assuming that there has actually been a state change rather than noise. The inverted signal is output from the signal output unit 86 to the receiving unit 9. On the other hand, if the sampling values obtained by sampling all do not match the values after the state change, the noise removing unit 80 assumes that noise has been mixed and the waveform shaped so as not to invert the logic of the sampled signal. The signal is output from the signal output unit 86 to the receiving unit 9.

  The noise processing unit 8 performs the above-described noise removal processing on each of the first vertical synchronization signal VSYNC1, the first horizontal synchronization signal HSYNC1, and the first effective interval signal S1. The noise processing unit 8 then generates a second vertical synchronization signal VSYNC2 that is a signal obtained by shaping the signal waveforms of the first vertical synchronization signal VSYNC1, the first horizontal synchronization signal HSYNC1, and the first effective interval signal S1 to remove noise. The second horizontal synchronization signal HSYNC2 and the second effective interval signal S2 are output from the signal output unit 86.

  Note that the noise processing unit 8 may be provided with a line memory 81 for storing a plurality of lines of image data output from the transmission unit 7. The line memory 81 outputs image data to the second image data memory 91 of the receiving unit 9.

  The receiving unit 9 synchronizes the transmission of the image data based on the second vertical synchronization signal VSYNC2, the second horizontal synchronization signal HSYNC2, and the second effective interval signal S2, and controls the acquisition and reception of the image data. A timing controller 90 is provided. The second timing controller 90 recognizes the start and end of transmission of one page of image data based on the second vertical synchronization signal VSYNC2. The second timing controller 90 recognizes line switching based on the second horizontal synchronization signal HSYNC2. Further, the second timing controller 90 recognizes a section in which transmission of image data is valid and a section in which transmission of image data is invalid based on the second valid section signal S2. Then, the second timing controller 90 causes the second image data memory 91 to acquire image data during the valid section. In other words, the receiving unit 9 (second timing controller 90) treats the data acquired in the second image data memory 91 in the valid section as valid image data.

(Image data transmission of data transmission apparatus 100)
Next, an example of the state change of the synchronization signal and the image data transmission in the data transmission apparatus 100 according to the embodiment will be described with reference to FIG. FIG. 5 is a timing chart illustrating an example of a state change of each signal when there is no noise in the data transmission apparatus 100.

  First, the state change of various synchronization signals and the transmission of image data in the data transmission apparatus 100 when there is no noise (normal time) will be described.

  The transmission unit 7 (the first timing controller 70) notifies the start of transmission of one page of image data and raises the first vertical synchronization signal VSYNC1 in order to synchronize transmission / reception of image data for one page ( t1). Although not shown in the timing chart of FIG. 5, when the transmission of image data for one page is completed, the first vertical synchronization signal VSYNC1 falls.

  The noise processing unit 8 recognizes the state change of the first vertical synchronization signal VSYNC1, and samples the state of the first vertical synchronization signal VSYNC1 a predetermined number of times. Then, when all the sampling values obtained by the sampling match with the value after the state change, the noise removing unit 80 determines that the state change really matches and the second vertical synchronization signal obtained by inverting the logic of the current state. VSYNC2 is output to the receiving unit 9 (at time t2). As shown in FIG. 5, since the sampling by the noise processing unit 8 has a certain time, it is determined in advance until the state change of the first vertical synchronization signal VSYNC1 is reflected in the state change of the second vertical synchronization signal VSYNC2. Deviation occurs for a certain time Δ1 minutes.

  The transmission unit 7 (the first timing controller 70) notifies the line change during the transmission of the image data, and sets the first horizontal synchronization signal HSYNC1 to synchronize the transmission / reception of the image data for one line. Lower (at time t3, t5).

  The noise processing unit 8 recognizes the state change of the first horizontal synchronization signal HSYNC1, and samples the state of the first horizontal synchronization signal HSYNC1 a predetermined number of times. Then, when all the sampling values obtained by sampling coincide with the values after the state change, the noise removing unit 80 determines that the state change really matches, and the second horizontal synchronization signal obtained by inverting the logic of the current state. HSYNC2 is output to the receiving unit 9 (at time t4 and t6). As shown in FIG. 5, since the sampling by the noise processing unit 8 has a certain time, it is determined in advance until the state change of the first horizontal synchronization signal HSYNC1 is reflected in the state change of the second horizontal synchronization signal HSYNC2. A deviation of a certain time Δ1 occurs.

  The transmitter 7 (the first timing controller 70) informs that the transmission of the image data is in an effective state, and sets the first effective interval signal S1 in order to synchronize the actual transmission and reception of the image data. Increase (at time t7). In addition, after the transmission of the image data for one line, the transmission unit 7 (the first timing controller 70) notifies the fact that the transmission of the image data for one line is completed and is in an invalid state. The section signal S1 falls (at time t8). As described above, in the description of the present embodiment, the section in the High state is the valid section, and the section in the Low state is the invalid section.

  The noise processing unit 8 recognizes the state change of the first effective interval signal S1, and samples the state of the first effective interval signal S1 a predetermined number of times. Then, the noise removal unit 80 determines that the state change really matches when all the sampling values obtained by the sampling match with the value after the state change, and the second effective interval signal obtained by inverting the logic of the current state. S2 is output to the receiving unit 9 (at time points t9 and t10). As shown in FIG. 5, since the sampling by the noise processing unit 8 has a certain time, it is determined in advance until the state change of the first effective section signal S1 is reflected in the state change of the second effective section signal S2. Deviation occurs for a certain time Δ1 minutes.

  Note that, as described above, after the first effective interval signal S1 becomes effective (after rising) by the processing of the noise processing unit 8, the second effective interval signal S2 becomes effective. A certain time Δ1 is required (until it rises). Therefore, at the same time when the first timing controller 701 changes the first valid section signal S1 to a state indicating validity and starts transmission of image data from the first image data memory 71 of the transmission unit 7 (at time t11). The second timing controller 90 of the receiving unit 9 cannot recognize that the transmission of the image data is valid.

  Therefore, in the present embodiment, for example, the line memory 81 of the noise processing unit 8 outputs the image data delayed by a predetermined time Δ1 toward the second image data memory 91 of the receiving unit 9. As a result, the image data is received by the receiving unit 9 without omission from the first pixel of the image data of one line (the image data delayed in FIG. 5 is shown as “image data D1 ′”, the same applies hereinafter). . Alternatively, without delaying to the line memory 81 of the noise processing unit 8, the first image data memory 71 of the transmission unit 7 transmits the image data in which dummy data for a certain time Δ1 is added to the head of the image data of one line. May be.

(Detection of delay of start of effective section due to noise mixture)
Next, an example of image data transmission when there is a delay in the start of an effective section due to noise mixing will be described with reference to FIGS. FIG. 6 is a timing chart for explaining a delay in the start of an effective section due to noise mixing in the data transmission apparatus 100. FIG. 7 is a flowchart illustrating an example of a flow of detection control of a delay in the start of an effective section due to noise mixing.

  First, the delay of the start of the effective section due to noise mixing will be described with reference to FIG. As shown in FIG. 6, before the first effective interval signal S1 rises (before entering the state indicating the effective interval), when noise is mixed in the first effective interval signal S1 (at time t12 in FIG. 6), The noise processing unit 8 samples the state of the first effective interval signal S1 for a predetermined number of times over a predetermined time Δ1 because the state of the first effective interval signal S1 has changed. At this time, since all of the sampling values obtained by the sampling do not coincide with the values after the state change, the noise processing unit 8 determines that the noise is present and keeps the state of the second effective section signal S2 unchanged. become.

  Here, while the noise processing unit 8 samples the state of the first effective interval signal S1 for a predetermined number of times over a certain time Δ1 and detects whether it is noise or not, the first effective interval is detected. There is a case where the signal S1 really switches (rises) (at time t13 in FIG. 6). In this case, after determining the noise, the noise processing unit 8 samples the state of the first valid interval signal S1 again for a predetermined number of times over a predetermined time Δ1, and then changes the second state to the state indicating validity. The state of the valid section signal S2 is switched (time t14 in FIG. 6).

  Thus, before the first effective interval signal S1 rises (before entering the state indicating the effective interval), if noise is mixed in the first effective interval signal S1, the second effective interval signal for the first effective interval signal S1. The change in S2 may be delayed further than a predetermined time Δ1 minutes (interval of t13 to t15) when there is no noise (interval of t13 to t14 in FIG. 6, indicated as constant time Δ1 + α).

  When the effective interval signal rises later than the change point of the normal second effective interval signal S2 (at time t15 in FIG. 6) due to noise mixing, the effective interval becomes shorter than normal (original). Therefore, in the image data of one line, the data of the pixel at the head portion is lost only by the delay of the start of the effective section due to noise (shift, section t15 to t14 in FIG. 6, section α). Then, the image quality of the image data is degraded. Therefore, due to noise, when the start of the effective section is delayed from the normal effective section, it is necessary to perform a process for preventing deterioration in image quality. For this purpose, it is necessary to detect that the start of the effective interval is delayed from the normal effective interval due to noise. First, detection of a delay in the start of an effective section due to noise mixing will be described with reference to FIG.

  First, the start in FIG. 7 is a point in time when reading of a document is started and generation of image data for one page is started in the image reading unit 2. Thereafter, the image data is sequentially transmitted from the transmission unit 7 to the reception unit 9. In this flowchart, start → end is repeated every time one page of image data is transmitted.

  The noise processing unit 8 then takes a time from the changing point (falling edge) of the second horizontal synchronization signal HSYNC2 to the changing point (rising edge, change to a state indicating validity) of the second effective interval signal S2 (FIG. 5). , Time T1) is measured for a plurality of lines (step # 1). Then, the noise processing unit 8 determines a first reference value based on the measured time (step # 2). For example, the noise removing unit 80 measures the time from the changing point for 5 to 20 lines to the changing point (less than the total number of lines of image data).

  Specifically, the time measuring unit 85 of the noise removing unit 80 measures the time from the change point of the second horizontal synchronization signal HSYNC2 to the change point of the second effective interval signal S2 for a plurality of lines. Then, the noise removal control unit 82 determines the first reference value based on the measured time and causes the reference value holding unit 84 to hold the first reference value. For example, the noise removal control unit 82 may determine the first reference value by taking the average of each time measured (average value), or may determine the most time as the first reference value (majority decision). Note that the time from the changing point (falling edge) of the first horizontal synchronization signal HSYNC1 to the changing point (rising edge, change to a state indicating validity) of the second effective interval signal S2 is acquired for a plurality of lines, and similarly A reference value may be set (shown as “time T1 ′” in FIG. 5).

  The noise processing unit 8 then, for the current line, the time from the changing point (falling edge) of the second horizontal synchronization signal HSYNC2 to the changing point (rising edge) of the second effective interval signal S2, and the first reference value Are compared (step # 3).

  Then, the noise processing unit 8 determines whether the effective section is shifted from the normal line due to noise in the current line (whether the start of the effective section is delayed due to noise mixing), and the start of the effective section due to noise is determined. The presence or absence of a delay is detected (step # 4). Details of the processing when the start of the effective section is delayed will be described later.

  Specifically, the noise removal control unit 82 obtains a first time difference that is a time difference between a change point of the first reference value and the second horizontal synchronization signal HSYNC2 and a change point of the second effective interval signal S2. And the noise removal control part 82 judges the presence or absence of the delay of the start of the effective area by noise by whether a 1st time difference is settled in the predetermined tolerance. The noise removal control unit 82 determines that there is a delay in the start of the effective section if the allowable range is exceeded, and determines that there is no delay in the start of the effective section if it falls within the allowable range. The allowable range is a range in which an error in the first time difference is allowed, and is a time shorter than a predetermined time Δ1 required for sampling the state of the first valid interval signal S1 a predetermined number of times.

  Then, the noise processing unit 8 confirms the second vertical synchronization signal VSYNC2 and confirms whether transmission of all lines has been completed (step # 5). If transmission of all lines is completed (Yes in step # 5), this flow ends (end). On the other hand, if transmission of all lines has not been completed (No in step # 5), transmission of image data of the next line is started due to a change in state of the first horizontal synchronization signal HSYNC1, the second horizontal synchronization signal HSYNC2, etc. (Step # 6). Thereafter, the process returns to step # 3.

(Processing when the start of the valid section is detected)
Next, based on FIGS. 8 and 9, an example of processing when a start delay of an effective section due to noise mixing is detected will be described. FIG. 8 is a flowchart showing an example of the flow of processing at the time of detecting the start delay of the effective section. FIG. 9 is an explanatory diagram showing an example of a setting screen 11a for setting correction of image data transmission when a delay in the start of the effective section is detected.

  First, the noise processing unit 8 according to the present embodiment performs processing for reducing image quality degradation in a line where it is detected that the start of the effective interval in the second effective interval signal S2 is delayed due to noise mixing. (Correction processing) is performed. And the start of FIG. 8 is the time of detecting the start delay of the effective section. Note that the flowchart of FIG. 8 is executed every time a start delay of the effective section is detected due to noise.

  Specifically, the noise processing unit 8 uses the line memory 81 that stores line image data, and in the line in which the delay of the start of the effective section is detected, the blank data, the image data of the previous line, or the first Any of the image data of the current line shifted by the time difference is output to the receiving unit 9 as image data. As described above, in the line where the delay of the start of the effective section is detected, the noise processing unit 8 transmits the corrected image data for one line (step # 22, details will be described later). Note that the noise processing unit 8 inputs the image data transmitted by the transmission unit 7 to the reception unit 9 as usual in a line that does not detect the delay of the start of the effective section.

  First, the noise processing unit 8 according to the present embodiment can output blank data (white data) to the receiving unit 9. At this time, the noise processing unit 8 causes the line memory 81 to transmit data indicating white for each pixel of the line to the receiving unit 9.

  For example, in a manuscript obtained by reading a character manuscript (document), since the area of the background portion (base portion) is originally wide, it may not be so noticeable even if one line is replaced with a pure white line. For this reason, it may be possible to suppress image quality deterioration and disturbance by replacing the data with lines that have been partially lost due to a delay in the start of the effective section, instead of printing with pure white lines. .

  Further, the noise processing unit 8 of the present embodiment can output the image data of the previous line to the receiving unit 9. The line memory 81 of the noise processing unit 8 stores image data of the previous line. When detecting the delay of the start of the effective section, the noise processing unit 8 causes the line memory 81 to output (transmit) the image data of the previous line to the reception unit 9. At this time, the image data of the previous line is sequentially transmitted in accordance with the change of the second valid section signal S2 to the valid state.

  For example, when printing is performed based on image data obtained by reading a character document (document), it is possible to perform printing before performing printing using data of a line partially lost due to a delay in the start of an effective section. In some cases, it is possible to suppress deterioration and disturbance of image quality by replacing the image data with lines.

  Further, when printing or the like is performed based on image data obtained by reading a photographic document, an unnatural color or image may appear if data of a line that is partially lost is used. On the other hand, in image data obtained by reading a photographic document, even if the image data is replaced with the image data of the previous line, the replacement may be noticed and hated.

  Further, since the noise processing unit 8 of the present embodiment can recognize the first time difference, the image data of the current line shifted (delayed) by the first time difference may be output to the receiving unit 9.

  Then, it can be set in advance on the operation panel 1 as shown in FIG. 9 as to which image data of the line in which the delay of the start of the effective section is detected is used.

  FIG. 9 shows an example of the setting screen 11 a displayed on the liquid crystal display unit 11 of the operation panel 1. The user can display the setting screen 11a relating to the correction of the image data of the line in which the delay of the start of the effective section is detected by performing input on the operation panel 1.

  In this setting screen 11a, depending on the type of document to be read (the type of image data transmitted from the transmission unit 7 of the image reading unit 2), the image data of the line in which the delay of the start of the valid section is detected by any method is used. It is possible to set whether to perform correction.

  Here, when a user performs a copy or scan using the liquid crystal display unit 11 and the touch panel unit 12 provided on the operation panel 1, “character original”, “photo original”, “character + photo”, and the like. The image quality of the original can be set. The operation panel 1 may be provided with hard keys for setting the image quality of the document such as “character document”, “photo document”, and “character + photo”.

  Depending on the image quality of the document, for example, the content of image processing performed by the image processing unit 52 changes. For example, when a character document is selected, the image processing unit 52 performs edge enhancement processing (differential filter processing) on the image data in order to make the character clear and clear. When a photographic document is selected, the image processing unit 52 performs a smoothing process (integral filter process) on the image data in order to reproduce a smooth color change. When “character + photo” is selected, the image processing unit 52 divides the image data into a character region and a photo region, and performs differential filter processing and integral filter processing on each region.

  The setting screen 11a is provided with a character + photo key K1, a character key K2, and a photo key K3. The user presses a key indicating the type of document to be set. When any key is pressed, the liquid crystal display unit 11 displays a setting selection area for selecting and setting the transmission method (correction content) of the image data of the line in which the delay of the start of the effective section is detected. In the setting selection area, a radio for selecting whether to output blank data, image data of the previous line, or image data of the current line shifted by the first time difference to the receiving unit 9 as image data. Buttons R1 to R3 are provided. The user presses one of the radio buttons to make a selection. The setting selection area is displayed every time the character + photo key K1, the character key K2, and the photo key K3 are pressed, and the image data of the line in which the start delay of the effective section is detected according to the type of image quality of the document. Can be selected.

  When the OK key K4 on the setting screen 11a is pressed, the setting content is stored in the storage unit 6. Then, the noise processing unit 8 detects the delay of the start of the effective section based on the setting of the image quality of the document input to the operation panel 1 and the setting content stored in the storage unit 6 when reading the document. Is confirmed how to correct (step # 21). Then, in the line in which the delay of the start of the effective section is detected, the noise processing unit 8 outputs the image data of the confirmed corrected line to the receiving unit 9 (Step # 22).

  If there is a delay in the start of the effective interval in the second effective interval signal S2, the effective interval becomes shorter than the original effective interval. Therefore, the noise processing unit 8 outputs, to the receiving unit 9, the second effective interval signal S2 with the first time difference and the effective interval lengthened on the line where the delay of the effective interval start is detected (step # 23 → end). . As a result, there is no shortage of pixels for one line.

(Detection of end of valid section due to noise)
Next, an example of image data transmission in the data transmission apparatus 100 according to the embodiment when there is a delay in the end of the effective section due to noise mixing will be described with reference to FIGS. 5, 10, and 11. FIG. 10 is a timing chart for explaining a delay in the end of the effective section due to noise mixing in the data transmission apparatus 100. FIG. 11 is a flowchart showing an example of a flow of detection control of the delay of the end of the effective section due to noise mixing.

  First, the delay of the end of the effective section due to noise mixing will be described with reference to FIG. As shown in FIG. 10, when noise is mixed in the first valid interval signal S1 before the first valid interval signal S1 falls (before completion of the valid interval, before entering the state indicating the invalid interval) (FIG. 10). 10 at time t21), the noise processing unit 8 samples the state of the first effective interval signal S1 a predetermined number of times over a certain time Δ1 because the state of the first effective interval signal S1 has changed. . At this time, all the sampling values obtained by sampling do not coincide with the value (Low) after the state change. For this reason, the noise processing unit 8 determines that the noise is noise and maintains the state of the second effective section signal S2 without changing (maintains High).

  Here, while the noise processing unit 8 samples the state of the first effective interval signal S1 for a predetermined number of times over a certain time Δ1 and detects whether it is noise or not, the first effective interval is detected. There are times when the signal S1 really switches (falls) (at time t22 in FIG. 10). In this case, after determining the noise, the noise processing unit 8 samples the state of the first valid interval signal S1 again for a predetermined number of times over a predetermined time Δ1, and then shows a state indicating invalidity (Low state). ) To switch the state of the second effective section signal S2 (at time t23 in FIG. 10). As described above, when noise is mixed in the first effective interval signal S1 before the first effective interval signal S1 falls (before entering the state indicating the invalid interval), the second effective interval for the first effective interval signal S1. There is a case where the change of the signal S2 is further delayed than a predetermined time Δ1 minutes (interval of t22 to t24) when there is no noise (interval of t22 to t23 in FIG. 10, indicated as constant time Δ1 + α). .

  If the effective interval signal falls further behind the change point t24 of the normal second effective interval signal S2 due to noise mixing, the effective interval becomes longer than normal. Therefore, in the image data of one line, the end portion of the image data is equivalent to the amount that the end of the effective section is delayed than usual due to noise (shift, section t24 to t23 in FIG. 10, section α). Extra pixel data is added to the.

  Then, the number of pixels of the image data per line changes, and there is a possibility of causing an abnormality in transmission processing or image processing. Then, due to noise, when the end of the effective interval is delayed from the normal effective interval, it is necessary to perform processing for extra pixels. For this purpose, it is necessary to detect that the end of the effective interval is delayed from the normal effective interval due to noise. First, detection of a delay in the start of an effective section due to noise mixing will be described with reference to FIG.

  First, the start of FIG. 11 is a point in time when reading of a document is started and generation of image data for one page is started in the image reading unit 2. Thereafter, the image data is sequentially transmitted from the transmission unit 7 to the reception unit 9. In this flowchart, start → end is repeated every time one page of image data is transmitted.

  Then, the noise processing unit 8 determines the time from the change point (falling edge) of the second horizontal synchronization signal HSYNC2 to the change point (falling edge, change point to a state indicating invalidity) of the second effective interval signal S2 ( In FIG. 5, time T2) is measured for a plurality of lines (step # 31). Then, the noise processing unit 8 determines the second reference value based on the measured time (step # 32). For example, the noise removing unit 80 measures the time from the changing point for 5 to 20 lines to the changing point (less than the total number of lines of image data).

  Specifically, the time measuring unit 85 of the noise removing unit 80 is from the changing point (falling) of the second horizontal synchronizing signal HSYNC2 to the changing point of the second effective interval signal S2 (falling, changing to a state indicating invalidity). Time is measured for multiple lines. Then, the noise removal control unit 82 determines the second reference value based on the measured time and causes the reference value holding unit 84 to hold the second reference value. For example, the noise removal control unit 82 may determine the second reference value by taking the average of each time measured (average value), or may determine the most time as the second reference value (majority decision). It should be noted that the time from the change point (falling edge) of the first horizontal synchronization signal HSYNC1 to the change point (falling edge) of the second effective interval signal S2 is acquired for a plurality of lines, and the reference value may be similarly set. (Indicated as “Time T2 ′” in FIG. 5)

  Then, the noise processing unit 8 includes the time from the change point (falling edge) of the second horizontal synchronization signal HSYNC2 to the change point (falling edge) of the second effective interval signal S2 on the current line, and the second reference. The values are compared (step # 33).

  Then, the noise processing unit 8 determines whether or not the effective section is deviated from the normal due to noise in the current line (whether the change in the second effective section signal S2 is delayed from the normal due to noise mixing), and the noise Whether or not there is a delay in the end of the effective section due to is detected (step # 34). Details of the processing when the end of the effective section is delayed will be described later.

  Specifically, the noise removal control unit 82 extends from the change point of the second reference value and the second horizontal synchronization signal HSYNC2 to the change point of the second effective interval signal S2 (change point to the state indicating falling and invalid). A second time difference that is a time difference is obtained. And the noise removal control part 82 judges the presence or absence of the delay of the start of the effective area by noise by whether a 2nd time difference is settled in the predetermined tolerance. The noise removal control unit 82 determines that there is a delay in the end of the effective section if it exceeds the allowable range, and determines that there is no delay in the end of the effective section if it falls within the allowable range. The allowable range is a range in which an error in the second time difference is allowed, and is a time shorter than a predetermined time Δ1 required for sampling the state of the first effective interval signal S1 a predetermined number of times.

  Then, the noise processing unit 8 confirms the second vertical synchronization signal VSYNC2 to confirm whether transmission of all lines has been completed (step # 35). If transmission of all lines is completed (Yes in step # 35), this flow ends (end). On the other hand, if transmission of all lines has not been completed (No in step # 35), transmission of image data of the next line is started by a change in the state of the first horizontal synchronization signals HSYNC1 and HSYNC2 (step # 36). ). Thereafter, the process returns to step # 33.

(Processing when the start of the valid section is detected)
Next, an example of processing performed when a delay in the end of the effective section due to noise mixing is detected will be described with reference to FIG.

  As shown in FIG. 10, when the effective interval signal falls after the change point t24 of the normal second effective interval signal S2 due to noise mixing, the effective interval becomes longer than normal. Therefore, in one line of image data, the end of the image data is equal to the end of the effective section that is later than usual due to noise (a section indicated by shading in the section from t24 to t23 in FIG. 10). Extra pixel data is added to the portion.

  Therefore, the noise processing unit 8 changes the state of the second effective interval signal S2 so that the effective interval after the second reference value is set as the ineffective interval in the line where the end of the effective interval is detected. In other words, the second effective interval signal S2 falls at the changing point t24, which is the time when the original effective interval signal ends. Thereby, it is possible to prevent the addition of extra pixel data to the image data of the line in the line where the delay of the end of the effective section is detected.

  Alternatively, the noise processing unit 8 gives an instruction to discard the data received in the effective period after the second reference value to the receiving unit 9 in the line where the delay of the end of the effective period is detected. Data received in the valid section after the second reference value may be treated as invalid.

  In this manner, the data transmission apparatus 100 according to the present embodiment changes its state with the image data, the first valid interval signal S1 indicating whether the image data is valid or invalid, and a predetermined cycle for one line. The transmission unit 7 that transmits a synchronization signal (for example, the first horizontal synchronization signal HSYNC1) indicating the switching of the line, receives the image data, the first effective interval signal S1, and the synchronization signal, and receives the image data and the synchronization signal (for example, , The second horizontal synchronizing signal HSYNC2) is output, and when the state of the first effective interval signal S1 changes, the state of the first effective interval signal S1 is sampled a predetermined number of times, and the same state continues. The logic is switched to the continued state after a predetermined number of times, and a noise processing unit 8 that generates and outputs a second effective interval signal S2 from which noise has been removed from the first effective interval signal S1, and noise Whether the image data output by the processing unit 8, the synchronization signal (for example, the second horizontal synchronization signal HSYNC2), and the second effective interval signal S2 are input, and the image data is an effective interval based on the second effective interval signal S2. And a receiving unit 9 that recognizes whether or not and acquires image data of an effective interval, and the noise processing unit 8 is a time from a change point of the synchronization signal to a change point of the second effective interval signal S2 for a plurality of lines. The reference value is obtained based on the measured time, and the time from the reference value and the change point of the synchronization signal to the change point of the second effective interval signal S2 is compared in each line, and the first effective interval signal S1 is obtained. Detects whether there is a shift in the effective section due to noise mixing.

  Accordingly, it is possible to detect a line in which a deviation occurs in the effective interval indicated by the second effective interval signal S2 by the process of removing noise generated at a timing close to the changing point of the first effective interval signal S1.

  In addition, the noise processing unit 8 extends from the change point of the synchronization signal (for example, the second horizontal synchronization signal HSYNC2) for a plurality of lines to the first change point of the second effective interval signal S2 indicating that the interval has become effective. The time is measured, the first reference value is obtained based on the measured time, and the first reference value and a first time difference that is a time difference from the change point of the synchronization signal of each line to the first change point is determined in advance. Whether or not there is a delay in the start of the effective section is detected depending on whether or not it falls within the range. As a result, it is possible to detect the occurrence of a shift (delay) at a point in time when the second effective interval signal S2 becomes effective (starting point of the effective interval).

  The noise processing unit 8 includes a line memory 81 for storing line image data. For a line in which a delay in the start of the effective section is detected, blank data, previous line image data, or first time difference shift is performed. Any image data of the current line is output to the receiving unit 9 as image data, and the image data transmitted by the transmitting unit 7 is input to the receiving unit 9 for a line that does not detect the delay of the start of the effective section. As a result, even if the change point indicating the start of the effective section shifts in the second effective section signal S2 due to noise and the start of image data acquisition in the receiving unit 9 is delayed, the content of the image data in the shifted line is corrected. Can do. Even if the start of the effective section is shifted, the influence on the image quality can be reduced.

  Further, the noise processing unit 8 outputs, to the receiving unit 9, the first effective time interval and the second effective interval signal S <b> 2 in which the effective interval is lengthened on the line where the start of the effective interval is detected. As a result, the effective section that has become shorter with the delay of the start of the effective section in the second effective section signal S2 is returned to the normal effective section length, and all the data for one line is sent to the receiving unit 9. Can be acquired.

  In addition, the receiving unit 9 receives, as image data, any one of blank data, previous line image data, or current line image data shifted by the first time difference with respect to the line in which the start of the effective section is detected. The noise processing unit 8 includes an input unit (operation panel 1) that receives a selection of whether to output to the input unit, and the noise processing unit 8 is a line that detects a delay in the start of the valid section in response to the selection input to the input unit. The line image data or the current line image data shifted by the first time difference is output to the receiving unit 9 as image data. As a result, the user can select a method for correcting the content of the image data in a line whose effective section is shifted due to noise. Therefore, the user can correct the image data on the line whose effective section is shifted by an arbitrary correction method.

  Also, the input unit determines the type of image data to be transmitted from the transmission unit 7, and according to the type of image data, blank data, previous line image data, or the current line shifted by the first time difference. The image processing apparatus receives an input that determines which image data is output to the receiving unit 9 as image data, and the noise processing unit 8 is a line in which a delay in the start of the effective section is detected, and is blank according to the type of the image data. The data, the image data of the previous line, or the image data of the current line shifted by the first time difference are output to the receiving unit 9 as image data. Thereby, for example, in the image data of the document, correction is made with the data of the previous line or the current line shifted by the first time difference, and the deterioration of the image quality due to the disturbance of the outline of the character is reduced. In the image data, it is possible to perform a desired correction according to the type of the image data on the line in which the noise is generated, such as reducing the deterioration of the image quality with the blank data.

  In addition, the noise processing unit 8 extends from the change point of the synchronization signal (for example, the second horizontal synchronization signal HSYNC2) for a plurality of lines to the second change point of the second valid interval signal S2 indicating that the interval becomes invalid. Time is measured, a second reference value is obtained based on the measured time, and a second reference value and a second time difference, which is a time difference from the change point of the synchronization signal of each line to the second change point, is determined in advance. Whether or not there is a delay in the end of the effective section is detected depending on whether or not the data falls within the range. As a result, it is possible to detect the occurrence of a shift (delay) at the time point when the second effective interval signal S2 becomes invalid (end point of the effective interval).

  Further, the noise processing unit 8 changes the state of the second effective interval signal S2 so that the effective interval after the second reference value is set as the ineffective interval in the line where the end of the effective interval is detected. Thereby, even if the change point of the second effective interval signal S2 indicating the end of the effective interval is shifted due to noise and the completion of image data acquisition in the receiving unit 9 is delayed, the influence on the content of the image data in the shifted line is affected. Can be reduced.

  The image forming apparatus (for example, the multifunction machine 101) includes a data transmission apparatus 100. Therefore, it is possible to provide an image forming apparatus capable of detecting a shift of an effective section due to noise mixing in a signal used for synchronization of transmission of image data. In addition, since printing can be performed based on image data in which the influence on the image quality is reduced, an image forming apparatus with high-quality printed matter can be provided.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention is applicable to a data transmission apparatus and an image forming apparatus equipped with the data transmission apparatus.

100 Data Transmission Device 101 Multifunction Device (Image Forming Device)
DESCRIPTION OF SYMBOLS 1 Operation panel (input part) 2 Image reading part 7 Transmission part 8 Noise processing part 81 Line memory 9 Receiving part S1 1st effective area signal S2 2nd effective area signal HSYNC1 1st horizontal synchronizing signal (synchronizing signal)
HSYNC2 Second horizontal synchronization signal (synchronization signal)

Claims (9)

A transmission unit that transmits image data, a first valid interval signal indicating whether the image data is valid or invalid, and a synchronization signal indicating a change of line, the state of which changes in a predetermined cycle for one line;
The image data, the effective interval signal, and the synchronization signal are input, the image data and the synchronization signal are output, and when the state of the first effective interval signal changes, the predetermined number of times Sampling the state of one effective interval signal, and switching the logic to the continued state when the same state continues for a predetermined number of times, and generating and outputting a second effective interval signal from which noise has been removed from the first effective interval signal A noise processing unit to
The image data output from the noise processing unit, the synchronization signal, and the second effective interval signal are input, and based on the second effective interval signal, recognize whether the image data is an effective interval, Receiving the image data of the valid section, and
The noise processing unit measures a time from a change point of the synchronization signal to a change point of the second effective interval signal for a plurality of lines, obtains a reference value based on the measured time, and calculates the reference value and the synchronization signal. The time from the change point to the change point of the second effective interval signal is compared for each line, and the presence or absence of deviation of the effective interval due to noise mixing in the first effective interval signal is detected. Transmission equipment.   The noise processing unit measures a time from a change point of the synchronization signal to a first change point of the second effective interval signal indicating that the interval has become effective for a plurality of lines, and based on the measured time, 1 reference value is obtained, and whether or not the first reference value and the first time difference that is the time difference from the change point of the synchronization signal of each line to the first change point falls within a predetermined allowable range, The data transmission apparatus according to claim 1, wherein the presence or absence of a delay in the start of the effective section is detected.   The noise processing unit includes a line memory for storing line image data, and in a line in which a delay in the start of the effective section is detected, blank data, previous line image data, or the first time difference is shifted. Output any image data of the current line to the receiving unit as image data, and input the image data transmitted by the transmitting unit to the receiving unit on a line that does not detect the start delay of the effective section. The data transmission device according to claim 2.   The noise processing unit outputs, to the receiving unit, the second effective interval signal obtained by extending the first time difference and the effective interval in a line in which the start delay of the effective interval is detected. Item 4. The data transmission device according to Item 2 or 3. The receiving unit uses any one of blank data, image data of the previous line, or image data of the current line shifted by the first time difference as the image data with respect to the line in which the start delay of the effective section is detected. Including an input unit that accepts selection of whether to output to
The noise processing unit is a line in which a delay in the start of the effective section is detected according to a selection input to the input unit, and is blank data, image data of the previous line, or the current time shifted by the first time difference. 5. The data transmission apparatus according to claim 3, wherein line image data is output to the receiving unit as the image data. The input unit determines the type of image data to be transmitted from the transmission unit, and depending on the type of the image data, blank data, previous line image data, or the current time shifted by the first time difference Accepting an input that determines which of the line image data is output to the receiving unit as image data;
The noise processing unit is a line in which a delay in the start of the effective section is detected, and according to the type of the image data, blank data, image data of the previous line, or the current line shifted by the first time difference. 6. The data transmission apparatus according to claim 5, wherein image data is output to the receiving unit as the image data.   The noise processing unit measures a time from a change point of the synchronization signal to a second change point of the second valid interval signal indicating that the interval becomes invalid for a plurality of lines, and based on the measured time, 2 reference values are obtained, and whether or not a second time difference, which is a time difference from the change point of the synchronization signal of each line to the second change point, falls within a predetermined allowable range, The data transmission apparatus according to claim 1, wherein the presence or absence of a delay in the end of the valid section is detected.   The noise processing unit changes the state of the second effective interval signal so that the effective interval after the second reference value is set as an invalid interval in a line in which a delay of the end of the effective interval is detected. The data transmission apparatus according to claim 7.   An image forming apparatus comprising the data transmission device according to claim 1.

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