JP2005153238A - Printing controller and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove trash images included in the horizontal scanning direction head of drawing data after block rotation. <P>SOLUTION: A printing controller 101 which converts the drawing data inputted from an external device 102 to video signals and outputs the signals to a printing engine part 103 is equipped with a DMA address control part 207 which calculates a differential value between a lateral width setting value of DMA for taking in the drawing data and a lateral width setting value for outputting the video signals to the printing engine part 103, means (207 and 205) for masking writing of a FIFO part 208 for outputting the video signals to the printing engine part 103 on the basis of the calculated differential value, and means (207 and 210) for setting a read address pointer of the FIFO part 208 on the basis of the calculated differential value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a print control apparatus and method, and more particularly, to a print control apparatus and method for fetching drawing data block-rotated by a VH rotator by DMA and transferring it as video data to a print engine.

  A print control device built in a printing apparatus such as a laser beam printer converts various input information supplied from an external device such as a host computer into a video signal and outputs the video signal to the print engine unit. When converting input information into a video signal, the print control apparatus performs image processing such as color correction, vertical / horizontal conversion according to recording paper, enlargement / reduction, and the like. Hereinafter, outputting drawing data that has been subjected to image processing by the print control apparatus as a video signal to the print engine unit is referred to as shipping. Shipping is performed in the video I / F control unit of the print control apparatus.

  Here, the vertical / horizontal conversion of the print control apparatus will be described. The print control apparatus creates band-level bitmap data from the drawing data and stores it in the memory. The VH rotator in the print control apparatus divides the bitmap data on the memory into basic block units, and further divides it into a plurality of rotation units. Vertical / horizontal conversion is performed for each rotation unit, and new bitmap data rotated by 90 degrees, 180 degrees, or 270 degrees is generated. The generated bitmap data is taken into the video I / F control unit and shipped to the print engine unit. The printing control apparatus includes a plurality of memories for efficient shipping, and transfers drawing data inside the apparatus by DMA (Direct Memory Access) control. Hereinafter, taking bitmap data after being rotated by the VH rotator into the video I / F control unit is referred to as SHIP_DMA.

  Next, drawing data before and after the rotation of the VH rotator will be described. FIG. 5 shows the drawing data. FIG. 5A shows drawing data in the case of normal A4 printing, and is in a state before rotation. The image area on the recording paper 501 is divided into blocks 502 of the VH rotator. Here, the width of the block 502 is BW and the height is BH. Due to the relationship between the block unit of the VH rotator and the size of the image area, a dust image 503 is included at the tail of the main scanning direction.

  A dust image is an image in which the drawing data on the memory is indefinite. In the memory, drawing data is stored in units of blocks, and the data that is not included in the image area in the last block in the main scanning direction is in an indefinite state. Here, the horizontal width of the dust image 503 is GW and the height is GH. The print engine unit outputs an image area with a main scanning head margin LM1 from a main scanning direction synchronization signal (hereinafter referred to as a BD signal).

  FIG. 5B shows drawing data in the case of A4-R printing, and shows a state after rotation. The image area on the recording paper 511 is divided by the rotated block 512. Due to the relationship between the block unit of the VH rotator and the size of the image area, a dust image 513 is included at the head in the main scanning direction. At this time, when shipping to the print engine unit, the main scanning head margin LM2 is set by reducing the height GH of the dust image 513, and the coordinates of the image area including the dust image 513 are relatively shifted to the left, The dust image 513 is configured to be masked.

  However, in the conventional print control method, the time interval (LM2) from the BD signal of the print engine unit to the image area to be shipped is short. In addition, after the rotation of the VH rotator, when the height BH of the block 512 is large, the height GH of the dust image 513 remaining at the head in the main scanning direction may be larger than the head margin in the main scanning direction. At this time, there is a problem that even if the image area including the dust image is relatively shifted to the left, it cannot be arranged at a regular position on the output paper.

  Further, in the case of each color data of 2 bits or 4 bits of video data constituting the image area, that is, monochrome multi-value data or YMCK color data, even if the block height BH after rotation is the same, The amount of DMA data in the main scanning direction of the rotated block increases. Since conventional SHIP_DMA performs DMA control in units of 8 word boundaries (256 pix for 1 bit / pix, 128 pix for 2 bit / pix, 64 pix for 4 bit / pix), the dust image to be masked may exceed the 8-word boundary. was there.

  The present invention has been made in view of such a problem, and an object of the present invention is to block regardless of the time interval from the BD signal to the image area to be shipped, regardless of the scan direction of the print engine unit. An object of the present invention is to provide a print control apparatus and method that can remove a dust image included in the head of the drawing data after rotation in the main scanning direction.

  In order to achieve such an object, the present invention provides a DMA width setting for capturing drawing data in a print control apparatus that converts drawing data input from an external device into a video signal and outputs it to a print engine unit. Means for calculating a difference value between a value and a width setting value for outputting a video signal to the print engine unit, and for outputting a video signal to the print engine unit based on the calculated difference value A means for masking FIFO writing and a means for setting a read address pointer of the FIFO based on the calculated difference value are provided.

  According to a second aspect of the present invention, in a print control apparatus that converts drawing data input from an external device into a video signal and outputs the video signal to the print engine unit, a first horizontal width setting value of DMA for capturing drawing data; A width setting means for setting a second width setting value for outputting a video signal to the print engine unit; and a difference value between the first and second width setting values, the number of 8 word boundaries and within 8 word boundaries A calculation means for calculating the fractional word number of the image data, a means for masking FIFO writing for outputting a video signal to the print engine unit based on the 8-word boundary number for each line, and the line for each line. A fractional word number within the 8-word boundary is set in the address pointer of the FIFO, and a bidet is set based on the address pointer. Characterized by comprising an address pointer designating means which is adapted to output a signal.

  According to a third aspect of the present invention, in the print control apparatus according to the second aspect, the calculating unit calculates the number of fractional words within the 8-word boundary based on the scan direction of the print engine unit. The address pointer designating unit sets signal information indicating the scan direction and outputs a video signal.

  According to the fourth aspect of the present invention, when drawing data in units of blocks is converted into a video signal and output to the print engine unit, drawing data not included in the image area of the recording paper is not output as a video signal. Drawing data not included in the image area based on a difference between a DMA horizontal width setting value for capturing drawing data and a horizontal width setting value for outputting a video signal to the print engine unit. A calculation step of calculating a horizontal width of the image, a mask step of masking writing of a FIFO for outputting a video signal to the print engine unit based on the calculated horizontal width, and drawing data included in the image area A write step for writing to the FIFO, and a read address pointer of the FIFO set based on the calculated width From data, characterized by comprising a reading step of reading the drawing data written in the FIFO.

  According to a fifth aspect of the present invention, in the printing control method according to the fourth aspect, the calculating step calculates the lateral width based on a scanning direction of the print engine unit, and the reading step includes the scanning direction. It reads out from the read address pointer based on the signal information indicating.

  As described above, according to the present invention, the horizontal width of drawing data not included in the image area is calculated from the difference between the horizontal width setting value of the DMA and the horizontal width setting value for outputting the video signal, and the FIFO writing is performed. Since the mask and the read address pointer are set and drawing data not included in the image area is not output as a video signal, the print engine unit does not depend on the time interval from the BD signal to the image area to be shipped. Regardless of the scan direction, it is possible to remove the dust image included at the beginning of the drawing data after the block rotation in the main scan direction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows the configuration of a print control apparatus according to an embodiment of the present invention. The print control unit 101 processes various input information supplied from an external device 102 such as a host computer, for example, a PDL (Page Description Language) file and an image image file, and outputs them as a video signal to the print engine unit 103. The external device 102 is connected to the print control unit 101 via an external interface such as IEEE1284 or USB, and sends recording information of various applications. Note that the external interface may be via a network such as a LAN. The print engine unit 103 forms an image on a recording sheet as a recording medium based on the video signal output from the print control unit 101.

  The print control unit 101 includes an ASIC 104, which is a highly integrated circuit including general access control for external devices and external elements, and an image processing function, a CPU 114, an MRAM 115, a BRAM 116, and a ROM 117.

  The internal circuit configuration of the ASIC 104 will be described. The CPU control unit 105 controls access between the CPU 114 and various devices. The MRAM control unit 106 controls the overall access to the MRAM 115 and has an arbitration function by DMA control from various devices. The ROM control unit 107 controls overall access to the ROM 117. The host I / F control unit 108 converts communication control with the external device 102 and various types of input information into a format that can be rendered. The BRAM control unit 109 controls the overall access to the BRAM 116 and has an arbitration function by DMA control from various devices.

  The compression / decompression control unit 110 compresses print output information with an algorithm such as JBIG and temporarily stores it in order to avoid an increase in the capacity of the MRAM 115 and BRAM 116, decompresses the print output information, and decompresses the video output control unit 113 in the subsequent stage. To send. The drawing control unit 111 creates band level bitmap data from the drawing command list configured on the MRAM 115 and performs overall control for drawing it on the BRAM 116 at a specified position and specified logic. The VH rotator 112 divides the band level bitmap data on the BRAM 116 created by the drawing control unit 111 into basic block units, and further divides it into a plurality of rotation units. Vertical / horizontal conversion is performed for each rotation unit, and new bitmap data rotated by 90 degrees, 180 degrees, or 270 degrees is generated. The video I / F control unit 113 performs communication control with the print engine unit 103 and outputs a serial video signal using a synchronization signal. This will be described later with reference to FIG.

  The CPU 114 generally controls access of various devices connected to the internal main bus based on the control program on the ROM 117. The MRAM 115 is a readable / writable storage device, functions as a main memory of the CPU 114, and is used as a work area for drawing processing and a development area for print output information. The BRAM 116 is a readable / writable storage device, and is used as a development area for band-level bitmap data created as a result of analysis / processing by the drawing control unit 111. The ROM 117 is a read-only storage device, and stores a control program for the CPU 114 and font data used when generating print output information.

  FIG. 2 shows a configuration of a video I / F control unit according to an embodiment of the present invention. The video I / F control unit 113 includes a SHIP_DMA control unit 201 and a shipping control unit 202, a register unit 203 for access between the CPU control unit 105 and the SHIP_DMA control unit 201, and a CPU control unit. 105 and a register unit 211 for access between the shipping control unit 202.

  The SHIP_DMA control unit 201 exchanges data with the MRAM control unit 106 or the BRAM control unit 109 by DMA control, and transmits data via the internal FIFO unit 208 while synchronizing with the shipping control unit 202. To do. The shipping control unit 202 performs communication control with the print engine unit 103. A synchronization signal is exchanged, various parameters relating to the print area are set, and a video signal to be printed on the output paper is generated. The register unit 203 controls an IO register for the video I / F control unit 113 with the CPU control unit 105.

  The function of each unit of the SHIP_DMA control unit 201 will be described. The DMA activation / clear unit 204 manages activation / clearing of the entire operation of the SHIP_DMA control unit 201. The DMA request handshake unit 205 performs handshaking while exchanging a DMA request and a DMA acknowledge with the MRAM control unit 106 or the BRAM control unit 109. Further, the write address of the FIFO unit 208 is managed, and exchange of DMA address parameters with the DMA address control unit 207 is performed.

  The DMA sequence unit 206 manages the entire operation sequence of the SHIP_DMA control unit 201, and outputs enable information to each block while taking timing with the shipping control unit 202. The DMA address control unit 207 generates a DMA address corresponding to the DMA request with the DMA activation signal as a trigger. In addition, the head load signal and the head cut data width, which are features of the present invention, are output to the video signal generator 210. The FIFO unit 208 receives the DMA data from the MRAM control unit 106 or the BRAM control unit 109, and writes based on the address parameter managed by the DMA request handshake unit 205.

  The parameter control unit 209 of the shipping control unit 202 manages the ordinate and abscissa on the output sheet, and outputs line end and band end signals to each block in the SHIP_DMA control unit 201. The video signal generation unit 210 takes in the data of the FIFO unit 208 based on information from the parameter control unit 209 and performs parallel-serial conversion to generate a video signal.

  A printing control method according to the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3A shows drawing data in the case of normal A4 printing, which is the same as FIG. 5A. FIG. 3B shows drawing data in the case of A4-R printing, and shows a state after rotation. Referring to the flowchart shown in FIG. 4, first, in order to start the print control apparatus, the DMA request handshake unit 205 of the SHIP_DMA control unit 201 sets the data amount per band to be shipped, that is, the SHIP_DMA band size. Set (S401). Next, a SHIP_DMA start address is set in the DMA address control unit 207 (S402), and various parameters necessary for shipping are set in the parameter control unit 209 (S403).

  In the present embodiment, the parameter set in step S403 has a horizontal width setting value A corresponding to the horizontal width of the image area. Apart from the horizontal width setting value A, the horizontal width setting value B of SHIP_DMA is set in the DMA address control unit 207 (S404). The width setting value A is an accurate width after the dust image is removed, whereas the width setting value B is a width corresponding to the rotated block width including the dust image.

  The DMA address control unit 207 calculates the difference between the horizontal width setting value A and the horizontal width setting value B. This difference corresponds to the width of the dust image 313 included in the head in the main scanning direction shown in FIG. 3B, that is, the height GH of the dust image 513. Hereinafter, it is also referred to as an earlobe region. Next, this difference is divided into an 8-word boundary number and a fraction within the 8-word boundary (S405). Specifically, when the horizontal width setting value A = 1000 pix and the horizontal width setting value B = 1151 pix, assuming 1 bit / pix, the 8-word boundary number is “1” and the fraction within the 8-word boundary is “255”. . Since masking (clip) processing can be performed within 1 word, in this embodiment, the fraction within 8 word boundary is set in units of words, and is set to “7”.

  The calculated 8-word boundary number and the fraction within the 8-word boundary are set in hardware in the DMA address control unit 207 (S407). The case where the left scan engine is not used will be described in the second embodiment. On the other hand, the fraction within the 8-word boundary is set in the video signal generation unit 210 by the DMA address control unit 207 in the form of the head cut data width and the head load signal at the head of the line (S409). When the necessary parameters are set in each block in this way, the DMA activation / clear unit 204 outputs an activation signal to each block and starts SHIP_DMA (S410). On the other hand, the shipping control unit 202 performs communication control with the print engine unit 103, exchanges synchronization signals, and matches the print area with the output paper.

  When SHIP_DMA is started, the video I / F control unit 113 captures drawing data via the MRAM control unit 106 or the BRAM control unit 109. The drawing data corresponding to the 8-word boundary number calculated in S405 performs a DMA handshake, but masks writing to the FIFO unit 208 (S411). It goes without saying that this processing is performed during the blanking period, so that shipping is not affected.

  Further, the address counter of the DMA address control unit 207 counts up because drawing data is taken in by DMA control, but does not affect shipping, and therefore does not affect the count control of the parameter control unit 209. When the drawing data corresponding to the 8-word boundary number has been skipped, the SHIP_DMA processing is continued, writing to the FIFO unit 208 is enabled, and normal shipping processing is started (S412).

  The video signal generation unit 210 fetches data from the FIFO unit 208 for shipping, but holds the head cut data width internally by the head load signal at the head of each line (or after the previous line ends) as described above. Only at the time of fetching the first 8 words, a pointer is added to the head cut data width, and data before that is not processed as data to be shipped (S413). Next, the DMA address is incremented (S415), and shipping is performed in units of word boundaries. Therefore, the address control of the DMA address control unit 207 may be a normal increment process.

  This operation is repeated for the number of lines in the band (S417), and the data amount per band to be shipped, that is, the SHIP_DMA band size is processed (S418). When the processing for one band is completed, the printing control apparatus similarly proceeds to the processing for the next band.

  As described above, according to the present embodiment, the horizontal width setting of SHIP_DMA and the horizontal width setting of the shipping parameter are separated, and the 8-word boundary number and the fractional word number within the 8-word boundary are calculated from the difference between them. And set. For drawing data with an 8-word boundary, writing to the FIFO is masked for each line (or at the end of the previous line), and for fractional words within the 8-word boundary, the line (or at the end of the previous line) ) Is set to the FIFO address pointer every time, and data before the pointer is not processed. In this way, regardless of the time interval from the BD signal to the image area to be shipped, even if a dust image is included in the drawing data after the block rotation, the dust image can be removed.

  A printing control method according to the second embodiment will be described with reference to FIGS. 3 and 4. In the first embodiment, the operation at the time of scanning band-level bitmap data from the left has been described. The second embodiment is a case in which a print engine unit in which the scanning direction is reversed is used by reducing the number of mirrors on the laser optical path as the cost of the print engine is reduced. When scanning from the right, the above-described dust image after the block rotation, that is, the edge region, may occur on the right side at the beginning of the main scanning direction.

  During left scanning, band-level bitmap data after block rotation is stored in the direction of LSB → MSB in the address increment direction in the MRAM 115 or BRAM 116. Therefore, the address control in SHIP_DMA may be incremented, and the video signal output order in the word may be LSB → MSB. On the other hand, during right scan, since it is necessary to proceed from right to left in units of one line for storage in the memory, address control in SHIP_DMA is decremented from the last address of one line data, and the first address While the video signal output order within the word must also be MSB → LSB.

  In the second embodiment, the value set in the DMA address control unit 207 or the DMA address control at the branch location (S406, S414, S419) of “whether it is the left scan engine?” In the flowchart of the first embodiment shown in FIG. The operation of the unit 207 is changed. Therefore, the scan direction signal output from the register unit 203 is input to the DMA request handshake unit 205, the DMA sequence unit 206, and the DMA address control unit 207 in the SHIP_DMA control unit 201.

  When the scanning direction signal indicates right scanning, the difference between the horizontal width setting value A of the shipping parameter and the horizontal width setting value B of SHIP_DMA is calculated and divided into an 8-word boundary number and a fractional word number within the 8-word boundary. Thus, when setting in the DMA address control unit 207, the fractional word number within the 8-word boundary is bit-inverted and set. When the video signal generation unit 210 captures data from the FIFO unit 208 for shipping, the video signal generation unit 210 holds the head cut data width by the head load signal at the head of the line (or after the previous line ends). Therefore, when fetching the first 8 words, a pointer is added to the head cut data width, and the data after that is not processed as data to be shipped.

  In the subsequent processing per line, as described above, the process decrements from the last address of one line data and proceeds to the first address. Then, after the processing for one line is completed and before the processing for the next line is started, a two-line offset is added for right scanning. This is because the scanning direction is reversed, but the paper transport direction is not different from that in the left scanning.

  As described above, in the second embodiment, only a part of the operation of the first embodiment is improved, and a dust image is included at the head of the drawing data after the block rotation in the main scanning direction regardless of the scan direction of the print engine. Even dust images can be removed.

1 is a block diagram illustrating a configuration of a print control apparatus according to an embodiment of the present invention. It is a block diagram which shows the structure of the video I / F control part concerning one Embodiment of this invention. It is a figure which shows the drawing data concerning the printing control method concerning one Embodiment of this invention. 6 is a flowchart illustrating a print control method according to an embodiment of the present invention. It is a figure which shows the drawing data concerning the conventional printing control method.

Explanation of symbols

201 SHIP_DMA control unit 202 Shipping control unit 203, 211 Register unit 204 DMA start / clear unit 205 DMA request handshake unit 206 DMA sequence unit 207 DMA address control unit 208 FIFO unit 209 Parameter control unit 210 Video signal generation unit

Claims (5)

In a print control device that converts drawing data input from an external device into a video signal and outputs it to a print engine unit.
Means for calculating a difference value between a horizontal width setting value for capturing drawing data and a horizontal width setting value for outputting a video signal to the print engine unit;
Means for masking writing of a FIFO for outputting a video signal to the print engine unit based on the calculated difference value;
And a means for setting a read address pointer of the FIFO based on the calculated difference value. In a print control device that converts drawing data input from an external device into a video signal and outputs it to a print engine unit.
A width setting means for setting a first width setting value of DMA for capturing drawing data and a second width setting value for outputting a video signal to the print engine unit;
Calculating means for calculating an 8-word boundary number and a fractional word number within the 8-word boundary from a difference value between the first and second width setting values;
Means for masking FIFO writing to output a video signal to the print engine unit based on the 8-word boundary number for each line;
Address pointer designating means for setting the number of fractional words within the 8-word boundary for each line to the address pointer of the FIFO and outputting a video signal based on the address pointer. Print control device. The calculation means calculates a fractional word number within the 8-word boundary based on a scan direction of the print engine unit;
The print control apparatus according to claim 2, wherein the address pointer designating unit sets signal information indicating the scan direction and outputs a video signal. In the print control method for preventing drawing data not included in the image area of the recording paper from being output as a video signal when the drawing data in block units is converted into a video signal and output to the print engine unit.
A calculation step for calculating a horizontal width of drawing data not included in the image area from a difference between a horizontal width setting value for DMA for capturing drawing data and a horizontal width setting value for outputting a video signal to the print engine unit; ,
A mask step for masking writing of a FIFO for outputting a video signal to the print engine unit based on the calculated horizontal width;
A writing step of writing the drawing data included in the image area into the FIFO;
A read control method comprising: a reading step of reading drawing data written in the FIFO from the read address pointer of the FIFO set based on the calculated horizontal width. The calculating step calculates the horizontal width based on a scan direction of the print engine unit,
The printing control method according to claim 4, wherein the reading step reads from the read address pointer based on signal information indicating the scan direction.

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