JP2005169716A - Printer control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of an apparatus by eliminating the normally required line memory between a decompression circuit and a recording unit without reducing the performance of the apparatus itself.
In an apparatus configured to transfer one line of VDO data (image data) between one pulse of HSYNC (main scanning synchronization signal), the decompressed image data output from the decompression circuit is transmitted. The appearance timing of the transfer VCLK for transferring the image data is controlled according to the decompression speed.
[Selection] Figure 4

Description

  The present invention relates to a control device in a printer apparatus.

  Conventionally, in an electrophotographic printer typified by a laser beam printer, print data (code data, image data, etc.) is received from an external device such as a host computer, and bits based on the received print data. The map data is expanded, and after the expansion is completed, the expanded bitmap data is output to the printer engine as video data.

  By the way, recent color printers are becoming cheaper and more sophisticated, and along with that, user's preference for color tone and tint is also improving.

  Recently, a host of software that can correct color tone and color by the host has become available, so it is possible to freely convert and correct colors, such as adjusting and outputting YMCK mixed colors to any color, considering balance and contrast. It has become an environment that can do.

In order to reduce the cost of the apparatus, the printer main body does not have a decompression function, and the host performs image processing and image compression. In the printer, the compressed image data is decompressed and transferred to VCLK for transfer. Devices that send image data to a recording unit in synchronization are also widespread (Patent Document 1).
JP 9-330193 A

  However, as described above, in an apparatus that does not have a development function in the printer body and prints while compressing compressed image data, the speed of the decompressed image data differs depending on the compressed data. A line memory for storing the decompressed image data is required between the decompression circuit and the recording unit.

  The stored image data is transmitted to the recording unit in synchronization with the main scanning synchronization signal and VCLK. While transmitting the image data, the decompressed data of the next line is written to the line memory, The image data of the next line to be sent is stored.

  In other words, since such control is performed, a line memory for several lines is required even though the apparatus is configured to be inexpensive, and a 4D color printer has 4 planes. Because it operates simultaneously, four times as many line memories are required.

  The present invention has been proposed in an apparatus for transferring image data to a recording unit in synchronization with a main scanning synchronization signal and VCLK while decompressing compressed image data sent from a host. As shown in the timing chart of (a), in an apparatus configured to transfer one line of VDO data (image data) between one pulse of HSYNC (main scanning synchronization signal), it is output from the decompression circuit. By controlling the appearance timing of the transfer VCLK that transfers the image data according to the decompression speed of the decompressed image data, the line memory between the decompression circuit and the recording unit, which is normally required, is maintained without reducing the performance of the device itself. It can be deleted and the cost of the device can be reduced.

  As described above, while compressing the compressed image data sent from the host, the image data is transferred to the recording unit in synchronization with the main scanning synchronization signal and VCLK, and one line of the image data is also transmitted. Transfer VCLK for transferring image data in accordance with the decompression speed of the decompressed image data output from the decompression circuit in an apparatus configured to transmit the minutes in one pulse of HSYNC (main scanning synchronization signal) By controlling the appearance timing and period of the image, the line memory between the normally required decompression circuit and the recording unit can be deleted without reducing the performance of the apparatus itself, and the cost of the apparatus can be reduced.

(Example 1)
Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 2 is a diagram showing a printing system to which the printer of the present invention is applied.

  In the drawing, reference numeral 2 denotes a printer which inputs data from various external devices such as a host computer and executes recording on a recording medium.

  In this embodiment, the printer 2 is a laser beam printer. The configuration of the laser beam printer to which this embodiment is applied will be described below with reference to FIG.

  FIG. 2 is a cross-sectional view showing the internal structure of the printer 2 of this embodiment. This printer can register a character pattern from a data source (not shown).

  In FIG. 2, reference numeral 2 denotes a printer body which inputs and stores print information (character code, etc.), form pattern information, compressed image data, etc. supplied from an externally connected host computer. Then, according to the information, a corresponding character pattern, form pattern, or the like is created, or an image is formed on a recording paper as a storage medium while developing compressed image data.

  Reference numeral 200 denotes an operation panel on which switches and LED indicators for various operations are arranged, and 201 denotes a printer control unit that executes overall control in the printer 2 and analyzes character information supplied from a host computer or the like. (Controller).

  The printer control unit 201 mainly converts character information into a video signal having a corresponding character pattern or transfers the compressed image data to the laser scanner unit 209 while expanding the compressed image data.

  When printing is started, the printer 2 starts a paper feeding operation for feeding recording paper into the apparatus from the paper feeding cassette 202 or the manual feed tray 203.

  The recording paper thus fed is sent to the paper feed unit 204 and conveyed so as to sequentially pass through the developing units 205, 206, 207 and 208.

  At the same time, the image data for each color developed by the controller 201 is sent to the laser scanner unit 209 after image conversion processing.

  The laser scanner unit 209 is a circuit for driving a semiconductor laser, and image data sent to the laser scanner unit 209 that switches ON / OFF of laser light emitted from the semiconductor laser according to input image data is For each color, the photosensitive drums of the phenomenon units 205, 206, 207, and 208 are laser-scanned based on the image data, and a desired color image is formed on the photosensitive drum corresponding to each color.

  By synchronizing the formation of the image data for each color with the conveyance of the recording paper, the color image of each color is developed on the recording paper conveyed by the conveyance unit 204.

  Further, sensors for detecting the remaining amount of toner are attached to the developing units 205, 206, 207, and 208, and information from the sensors is sent to the control system of the recording unit in accordance with the decrease in toner.

  The recording paper on which the color image is printed in this manner is thermally fixed by the fixing unit 210 and is abolished in the paper feed tray 211.

  With such a configuration of the printer 2, since development can be performed independently for each color, a printed image can be obtained at a very high speed.

  FIG. 1 is a block diagram showing a detailed configuration of the printer control unit 201 in the printer 2 described above. In FIG. 1, reference numeral 101 denotes an interface unit (I / F unit), which is an external device (host computer, image scanner, etc.). ) Input code data and compressed image data.

  A CPU 102 controls the entire printer.

  Reference numeral 103 denotes a RAM unit which provides an area for storing recording data sent from the host computer for printing, and a work area necessary for the CPU 102 to execute various controls as a work memory.

  A ROM unit 104 stores an area for storing various programs (firmware) to be executed by the CPU 102 and various font data for image development of code data.

  Reference numeral 105 denotes a block for controlling data DMA transfer and arbitration between blocks.

  The decompression circuits 106, 107, 108, and 109 output the compressed image data stored in the RAM unit 103 from the RAM unit 103 according to the arbitration of the control unit 105 according to the request signal output from each decompression circuit. Means for receiving compressed image data.

  In the decompression circuit, one decompression circuit exists for each of yellow (Y), magenta (M), cyan (C), and black (K), decompressing the compressed image data transferred from the RAM unit 103, Output via I / F section.

  Also, the I / F units 110, 111, 112, and 113 always exchange command and status with the recording unit at regular intervals, grasp the state of the recording unit, send a print command, etc. We are communicating with.

  The I / F unit also generates a sub-scan enable signal and a main-scan enable signal based on the input synchronization signal (sub-scan synchronization signal, main-scan synchronization signal), and in accordance with the generated enable signal, an expansion circuit Request image data and convert the image data input from the decompression circuit into video data according to the output gradation (1 pixel is converted into 1 bit, 2 bits, 4 bits, etc. according to the output gradation) And transferred to the recording unit together with the transfer CLK.

  Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

  First, when a print command is sent from an external device (such as a host computer) from S401, based on the sent data, the I / F unit (YMCK) 110, 111, 112 with each recording unit, The video data output range (top margin, left margin, sub-scan output range, main scan output range, etc.) is set in 113.

  Simultaneously with the setting of the output range, compressed image data (YMCK) is transferred from the host computer from S 402 and stored in the RAM unit 103.

  When the fixed value of compressed image data is stored in the RAM 103, a print start command is sent to the recording unit from S403, and the recording unit starts the printing operation.

  The recording unit that has started the printing operation outputs a sub-scanning synchronization signal and a main-scanning synchronization signal (HSYNC) to the controller.

  3 (a) and 3 (b) show timing charts in the conventional image data transfer. First, after the left margin of a certain number of dots, the VDO signal is output after the falling edge of HSYNC as a reference. Is output.

  Here, VCLK is always output, and in the recording unit, one line of image data is obtained when a certain number of VDO data is input within the transfer range of one line.

  In S <b> 404, in response to HSYNC output from the recording unit, each decompression circuit makes a request for compressed image data to the control unit 105.

  Upon receiving the request, the control unit 105 starts reading the compressed image data accumulated in the previous period to the RAM unit 103 and transfers the compressed image data to the decompression circuit.

  In S405, decompression of the input compressed image data is started, and the decompressed VDO data is transferred to the I / F unit as needed.

  In S406, it is determined whether or not the decompressed VDO data has been input from the decompression circuit. If it has been input, it is transferred to the recording unit simultaneously with VCLK.

  FIG. 3- (c) shows a timing chart at that time. VDO data and VCLK are transmitted to the recording unit only when the VDO data is output from the decompression circuit, and the decompressed VDO data is output from the decompression circuit. If not, the VDO signal and VCLK are not transmitted to the recording unit.

  In S408, it is determined whether or not one line of pixels has been transferred to the recording unit. If one line of pixels has not been transferred, the process returns to S405 to continue the data request to the control unit 105. If pixels for one line have been transferred, the process proceeds to S409.

  In S409, it is determined whether or not the line transfer for one page has been completed. If not, the process returns to S404 to wait for the next HSYNC signal, and the line transfer for one page is completed. If so, printing ends.

(Example 2)
In the above embodiment, in S406 of the flowchart of FIG. 4, it is determined whether or not the expanded VDO data is input from the expansion circuit. Otherwise, control is made to wait in a state of waiting for input, but as VDO data transfer CLK, means and several words that can change the cycle of VCLK for transferring image data as shown in FIG. By adopting a configuration in which the buffer for the minute is provided in the circuit of the I / F unit, the state in which the decompressed image data is accumulated in the buffer in the previous period is monitored, and thereby the transfer period of VDO data to be transferred and VCLK is transferred. By controlling the change, the same effect as in the above embodiment can be obtained.

Block diagram of printer control device Block diagram of the printer Video data transfer timing chart Flow chart of this embodiment

Explanation of symbols

101 I / F unit 102 CPU
103 RAM section 104 ROM section 105 Control section 106 Decompression circuit M
107 Decompression circuit C
108 Expansion circuit Y
109 Expansion circuit K
110 I / F part M
111 I / F part C
112 I / F part Y
113 I / F part K

Claims (2)

  An apparatus comprising: means for receiving compressed image data from an external device; means for decompressing the compressed image data; and means for transferring the decompressed image data to a recording means in synchronization with video CLK. A printer that generates the transfer video CLK in accordance with a decompression speed of decompression means for decompressing compressed image data, and transfers the decompressed image data in synchronization with the video CLK. Control device. Means for changing the frequency of the video CLK for transferring the image data is provided, and the frequency of the video CLK for transfer is changed according to the expansion speed of the expansion means for expanding the compressed image data. A printer control apparatus, wherein the decompressed image data is transferred in synchronization with CLK.

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