JP2005349755A - Color printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color printer capable of effectively functioning a reception buffer memory of a color printer when data of each recording color component is compressed and transmitted from an information processing apparatus such as a host computer to the color printer. It is for the purpose.

A reception buffer for temporarily storing image data compression-coded for each of cyan, magenta, yellow, and black color components is divided into first to fifth areas in advance, and the first, second, The memory division means for assigning the third and fourth areas to cyan, magenta, and yellow image data, and assigning the fifth area to an arbitrary color after the start of print data reception, and the received encoded data for cyan, magenta The color printer decodes image data independently for each of the yellow, black, and black color components.

[Selection] Figure 1

Description

The present invention relates to a color printer that prints a color image.

  In a color printer that receives print data from a host computer and performs printing, a technique is known in which a buffer memory of the same size is secured in advance for each color component, and these are used as a ring buffer.

  According to this technique, printing can be performed by effectively utilizing a small memory capacity, and the cost of the color printer can be reduced.

Conventionally, a technique relating to buffer control of a printer is known (for example, see Patent Document 1).
JP-A-8-25754

  However, at present, the resolution requirement of the user's printer has increased, and the amount of data transferred from the host computer to the printer has become enormous. In order to cope with this, it is necessary to compress the image data to be printed and reduce the amount of data, thereby reducing the amount of memory required and reducing costs while efficiently transferring data. can do.

  Here, the compressed data amount of each color component is generally not the same ratio.

  Therefore, in the above conventional example, when the ring buffer is secured with the same size for each recording color component, it cannot be said that the memory utilization efficiency is high, and there is a problem that the reception buffer memory cannot be effectively functioned.

  In other words, the conventional example has a problem that data transfer may not be in time for the recording speed when the image data of a specific color component is large due to the difference in compression rate.

  Further, the conventional example has a problem that the required memory size becomes large when the memory amount is set so as to be surely in time.

The present invention provides a color printer capable of effectively functioning a reception buffer memory of a color printer when data of each recording color component is compressed and transmitted from an information processing apparatus such as a host computer to the color printer. It is intended to do.

The present invention is a color printer that receives print data and records a color image on a predetermined storage medium, receives image data that has been compression-coded for each color component of cyan, magenta, yellow, and black, and temporarily The reception buffer to be stored in and the reception buffer are divided in advance into first to fifth areas, the first area is assigned to cyan image data, the second area is assigned to magenta image data, and Memory dividing means for allocating the third area to yellow image data, allocating the fourth area to black image data, and allocating the fifth area to an arbitrary color after printing data reception starts, and received encoding A plurality of decoding means for decoding data into image data independently for each of the cyan, magenta, yellow, and black color components; Is a color printer having.

According to the present invention, when data of each recording color component is compressed and transmitted from an information processing apparatus such as a host computer to a color printer, the reception buffer memory of the color printer can be effectively functioned. Play.

  The best mode for carrying out the invention is the following embodiment.

  FIG. 1 is a block diagram illustrating a color printer 10 and a host computer 1 that are Embodiment 1 of the present invention.

  The host computer 1 includes an operating system (OS) 2, an application 3, a printer driver 4, a language monitor 5, and a USB port driver 6.

  The host computer 1 is a computer such as a personal computer that generates print data. The host computer 1 is a hardware such as a CPU, a memory, a hard disk, a floppy disk drive, a keyboard, a pointing device such as a mouse, a monitor, and a USB port. As shown).

  An operating system (OS) 2 manages hardware included in the host computer 1 and software such as an application 3, a printer driver 4, a language monitor 5, and a USB port driver 6.

  The application 3 is application software such as a word processor, and creates and prints a document in accordance with an instruction from the operator.

  The printer driver 4 receives a print command issued by the application 3 via the operating system 2 and converts the print command into a printer command that can be interpreted by the language monitor 5 and the color printer 10.

  The language monitor 5 receives the printer command output from the printer driver 4 and transmits it to the color printer 10 via the USB port driver 6.

  The USB port driver 6 transmits the printer command output from the language monitor 5 to the color printer 10 via the USB port, and outputs the printer command to the language monitor 5 when receiving a status from the color printer 10.

  The color printer 10 performs printing according to the printer command received from the USB port driver 6. The first embodiment is an example in which the color printer 10 and the host computer 1 are connected via a USB interface. However, the color printer 10 and the host computer 1 may be connected via another interface, for example, a network.

  FIG. 2 is a block diagram illustrating the configuration of the color printer 10 according to the first embodiment.

  The color printer 10 includes a USB port 11, a DMA controller 12, a memory 13, decoding circuits 14 Y, 14 M, 14 C, and 14 K, a printer engine 15, and a control circuit 16.

  The USB port 11 receives print data including a printer command from the computer 1. As described above, the interface connected to the host computer 1 is not limited to USB, and a network interface may be used.

  The DMA controller 12 stores image data received via the USB port 11 in the memory 13, and yellow (hereinafter referred to as Y), magenta (hereinafter referred to as M), cyan (hereinafter referred to as “image data”) read out from the memory 13. C) and black (hereinafter referred to as K) components are output to the decoding circuits 14Y, 14M, 14C, and 14K prepared for the respective components.

  The memory 13 has a capacity of, for example, 16 Mbytes, stores image data under the control of the DMA controller 12, and functions as a ring buffer. The memory 13 has five logical channels, for example, four 3.8M bytes. It has a capacity of a byte memory and one 0.8 Mbyte memory, and operates as a FIFO (First In First Out) memory.

  The decoding circuits 14Y, 14M, 14C, and 14K each decode the compressed image data stored in the memory 13 and output the decoded image data to the printer engine 15. Each of the decoding circuits 14Y, 14M, 14C, and 14K is an independent circuit and can simultaneously decode the image data of each channel.

  The printer engine 15 is a laser beam printer engine, and prints according to the image data output from the decoding circuits 14Y, 14M, 14C, and 14K according to an instruction from the control circuit 16. The printer engine 15 has four drums, and simultaneously prints image data of each channel as image data of four colors Y, M, C, and K.

  The control circuit 16 is composed of, for example, a one-chip CPU, and controls the entire color printer 10 such as the USB port 11, the DMA controller 12, the memory 13, the decoding circuit 14, and the printer engine 15.

  Next, the configuration of the printer engine 15 in the first embodiment will be described.

  FIG. 3 is a conceptual diagram illustrating the printer engine 15 according to the first embodiment.

  FIG. 4 is a conceptual diagram illustrating the scanner unit 301 in the printer engine 15 according to the first embodiment.

  The printer engine 15 visualizes each image data of Y, M, C, and K by an electrophotographic process and transfers it to a transfer material. The image generation unit includes four similar blocks corresponding to Y, M, C, and K, respectively. Hereinafter, yellow (Y) will be described in detail as an example.

  The scanner unit 301 includes a laser driver 312, a laser light emitting unit 313Y, a collimator lens 314Y, a polygon motor 315Y, a polyhedral mirror 316Y, an imaging lens 317Y, a mirror 318Y, a photosensitive drum 319Y, and a fixed mirror 320Y. And a light receiving element 321Y. Note that the scanner unit 301 has the same configuration as that for yellow (Y) for magenta (M), cyan (C), and black (K).

  When attention is paid to yellow (Y), the laser driver 312 drives the laser emission unit 313Y in accordance with the image data output from the printer image processing unit 352. Here, the printer image processing unit 352 includes the decoding circuits 14Y, 14M, 14C, and 14K shown in FIG. 2, and the image data is output by the decoding circuits 14Y, 14M, 14C, and 14K. The laser light emitting unit 313Y modulates and outputs a laser beam according to the image data output from the printer image processing unit 352. The modulated laser beam is converted into parallel light by the collimator lens 314Y, and then incident on the polyhedral mirror 316Y that rotates at a constant speed by the rotation of the polygon motor 315Y.

  The image forming lens 317Y arranged in front of the polyhedral mirror 316Y is focused on the photosensitive drum 319Y via the mirror 318Y. When the polyhedral mirror 316Y rotates at a constant speed, the laser beam scans on the photosensitive drum 319Y at a constant speed. When the photosensitive drum 319Y rotates at a constant speed and the laser beam scans the photosensitive drum 319Y at a constant speed, an electrostatic latent image is formed on the photosensitive drum 319Y.

  The fixed mirror 320Y is disposed in the optical path of the laser beam, and the laser beam that has reached the scanning start position is reflected by the fixed mirror 320Y and is incident on the light receiving element 321Y. The light incident on the light receiving element 321Y is converted into a current by the light receiving element 321Y, and further subjected to current-voltage conversion, which is used to generate a horizontal synchronizing signal.

  The photosensitive drum 319Y includes a conductive drum and a photoconductive layer. Around the photosensitive drum 319Y, a primary charger 322Y, a developing device 323Y, a transfer charger 324Y, a blade type cleaning device 325Y (not shown), and a static eliminator 326Y ( (Not shown) is configured.

  The photosensitive drum 319Y, the primary charger 322Y, the developing sleeve 323Ya (not shown) in the developing device 323Y, and the transfer charger 324Y are driven by a motor 327. The surface of the driven photosensitive drum 319Y passes through the primary charger 322Y, so that the surface thereof is uniformly charged directly to minus, and thereafter, the laser beam is received from the laser emission unit 313Y and exposed. By this laser light irradiation, the negative charge in the bright part is neutralized and an electrostatic latent image is formed.

  When the electrostatic latent image comes close to the yellow developer YT in the developing device 323Y, the negatively charged developer YT causes the surface of the photosensitive drum 319Y to have a potential difference between the potential of the latent image and the potential of the developing device 323Y. Jump to the visible image.

  Then, a positive charge is applied by the transfer charger 324Y, and the toner image on the photosensitive drum 319Y is transferred onto the transfer material P. In addition, after the transfer device 325Y removes residual toner on the surface of the photosensitive drum 319Y after the transfer, the primary charger 322Y makes the drum potential uniform to prepare for the formation of the next electrostatic latent image. The residual toner removed from the drum surface is collected in a developer collection container (not shown).

  Now, in magenta (M), cyan (C), and black (K), the magenta developer MT, cyan developer CT, and black developer KT are used on the photosensitive drums 319M, 319C, and 319K, respectively. An image is generated in the same process as in FIG. Then, the image is transferred onto the transfer agent P, and a full color printout is performed.

  Here, the photosensitive drums 319Y, 319M, 319C, and 319K for each color component are arranged at a predetermined interval d. Therefore, by driving the decoding circuits 14Y, 14M, 14C, and 14K shown in FIG. 2 while being shifted by the timing corresponding to the distance d and the conveyance speed of the recording paper, the image is placed at a predetermined position on the transfer material P. Are superimposed. That is, when attention is paid to the same timing, the decoding circuits 14Y, 14M, 14C, and 14K simultaneously decode the image data at the printing position.

Now, the transfer material P is set in the paper cassette 360, fed at a timing synchronized with the start of laser light irradiation, passed through the registration roller 333, and conveyed in the direction of the arrow shown in FIG. The transfer material P is transferred to the fixing unit 335 after the developers YT, MT, CT, and KT attached to the photosensitive drums 319Y, 319M, 319C, and 319K are transferred. The developers YT, MT, CT, and KT transferred to the transfer material P conveyed to the fixing unit 335 are fixed to the transfer material P by heat and pressure. The transfer material P that has passed through the fixing unit 335 is discharged by a discharge roller 338.

  In the first embodiment, dither processing can be performed on the host computer side to generate image data of 2 bits per pixel. Further, the printer engine 15 can record an image of 2 bits per pixel (that is, 4 gradations) for each color component by PWM pulse modulating the laser beam.

  Next, features that are characteristic of the first embodiment will be described.

  FIG. 5 is a block diagram showing a ring buffer provided in the color printer 10.

  The ring buffer includes a DMA controller 12 and a memory 13.

  The memory 13 includes a memory block MB1 (first area), a memory block MB2 (second area), a memory block MB3 (third area), a memory block MB4 (fourth area), and a memory block MB5 (fifth area). Are divided into five memory blocks (areas).

  Here, the memory block MB1 is pre-assigned to Y, the memory block MB2 is pre-assigned to M, the memory block MB3 is pre-assigned to C, and the memory block MB4 is pre-assigned to K.

  The boundary data 200 to 205 is boundary data built in the DMA controller 12. That is, the boundary data 200 indicates the start position of the memory block MB1, the boundary data 201 indicates the end position of the memory block MB1 and the start position of the memory block MB2, and the boundary data 202 indicates the end position of the memory block MB2. The boundary data 203 indicates the end position of the memory block MB3 and the start position of the memory block MB4, and the boundary data 204 indicates the end position of the memory block MB4 and the memory block MB5. The start position is indicated, and the boundary data 205 indicates the end position of the memory block MB5.

  The read pointer control circuits 211 to 214 are read pointer control circuits built in the DMA controller 12 and hold addresses for reading data from the memory blocks MB to the decoding circuits 14Y, M, C, and K. The DMA controller 12 updates the address of the next data to be read according to the read data size.

  The write pointer control circuits 221 to 224 are write pointer control circuits built in the DMA controller 12 and hold addresses for writing Y, M, C, and K print data from the host computer 1 in each memory block MB. In addition, the DMA controller 12 updates the address of the next data to be written according to the written data size.

  The comparison address setting registers 231 to 234 are data registers built in the DMA controller 12.

  The comparators 241 to 244 are built in the DMA controller 12 and whether or not the write pointers 221 to 224 starting from the boundary data 200, 201, 202, 203 have reached the comparison address set by the comparison data registers 231 to 234. Is detected.

  Here, the DMA controller 12 assigns the memory block MB5 to the color component indicated by the write pointer that reaches the comparison address earliest in one page print. That is, if the write pointer that has reached the comparison address earliest is the Y write pointer, the Y address space is the boundary data 200 to 201 and the boundary data 204 to 205.

  In this case, the DMA controller 12 includes the write pointer control circuits 221, 222, 223, and 224, the read pointer control circuits 211, 212, 213, and 214, the comparators 241, 242, 243, and 244, and the comparison address setting register 231. 232, 233, 234.

  In the DMA controller 12, when the write pointer control circuit 221 or the read pointer control circuit 211 reaches the boundary data 201, the next address is controlled to be 204 and the ring memory is updated. When the write pointer control circuit 221 or the read pointer control circuit 211 reaches the end address 205, the next address is updated to become the start address 200.

  Similarly to the above, if the write pointer that has reached the comparison address earliest is the write pointer for M, the address space of M becomes boundary data 201-202 and boundary data 204-205.

  In this case, in the DMA controller 12, when the write pointer control circuit 222 or the read pointer control circuit 212 reaches the boundary data 202, the next address is controlled to be 204 and the ring memory is updated. When the write pointer control circuit 222 or the read pointer control circuit 212 reaches the end address 205, the next address is updated to become the start address 201.

  Similarly to the above, if the write pointer that reaches the comparison address earliest is the C write pointer, the address space of C is the boundary data 202 to 203 and the boundary data 204 to 205.

  In this case, in the DMA controller 12, when the write pointer control circuit 223 or the read pointer control circuit 213 reaches the boundary data 203, control is performed so that the next address becomes 204, and the ring memory is updated. When the write pointer control circuit 223 or the read pointer control circuit 213 reaches the end address 205, the next address is updated to be the start address 202.

  Similarly to the above, if the write pointer that reaches the comparison address earliest is the K write pointer, the address space of K becomes boundary data 203 to 204 and boundary data 204 to 205.

  In this case, in the DMA controller 12, when the write pointer control circuit 224 or the read pointer control circuit 214 reaches the boundary data 204, control is performed so that the next address becomes 204, and the ring memory is updated. When the write pointer control circuit 224 or the read pointer control circuit 214 reaches the end address 205, the next address is updated so as to become the start address 203.

  Hereinafter, the printing operation in the first embodiment will be described.

  When the operator operates the application 3 running on the host computer 1 to generate print data and instruct to print it, a print command is passed from the application 3 to the printer driver 4 via the operating system 2. It is.

  The printer driver 4 converts the image data into image data based on the print command issued from the application 3, compresses the image data, and specifies the paper size, the line length of the bitmap data, the number of lines, etc. Output together with a condition specification command and a page end command indicating page end.

  The output printer command is passed to the language monitor 5 via the operating system 2. The language monitor 5 transfers the received printer command to the color printer 10. When receiving the print condition designation command, the color printer 10 instructs the printer engine 15 to start printing. Further, when receiving the image data command, the color printer 10 stores the image data for each recording color component in the corresponding memory block MB in the memory 13 according to the write pointer, and updates the write pointer.

  When the printer engine 15 receives a print instruction, the printer engine 15 starts feeding paper, and requests output of image data when the fed paper reaches a predetermined position. When output of image data is requested, each decoding circuit 14 requests reading of image data stored in one of the memory blocks MB of the memory 13 via the DMA controller 12.

  The DMA controller 12 accepts this read request, reads from the data indicated by the read pointer of the corresponding memory block MB, and outputs the read data to the requesting decoding circuit. At this time, the read pointer is updated, but the address space in which the already read data is stored becomes a free area in which subsequent image data can be stored. The decoding circuit 14 decodes the data transferred by the DMA controller 12 and outputs it to the printer engine 15.

  Next, details of processing of the printer driver 4 in the host computer 1 will be described.

  FIG. 6 is a flowchart showing an operation when the printer driver 4 receives data for one drawing unit from the operating system 2.

  Note that when printing one page, the operation of the flowchart shown in FIG. 6 is executed a plurality of times.

  First, in S6, it is determined whether or not the data type passed from the operating system 2 is a page start command. If it is not a page start command, as shown in S7, other processing corresponding to the type of data (for example, processing corresponding to a printer capability inquiry command or the like) is executed, and the process returns to S6.

  In S6, if the data type is a page start command, it is determined whether the data type is a drawing command, as shown in S1. If it is a drawing command, a drawing process is performed as shown in S2.

  Here, the drawing data is generated by 8 bits for each color of red (R), green (G), and blue (B). For example, when a font type, font size, or character code is received, a character pattern corresponding to that is generated and drawing data of the image data is created. In the case of a halftone image, the received image data is placed at a specified position. Create drawing data.

  Next, in S9, an area attribute table indicating the area position of the drawn image shown in S2 and the attribute of the area (that is, an area attribute indicating whether the drawing is a character / line drawing or a halftone image) is created. To do. This area attribute table is reset at the start of one page. In addition, when the operating system 2 receives information indicating the end of one page, it is possible to determine which area is a character line drawing and which area is a halftone image area by referring to the area attribute table. Can be recognized. After creating the region attribute table, the process returns to S1.

  If the data type is not a drawing command in S1, it is determined in S3 whether the data type is a page end command. If the data type is a page end command, color conversion processing and quantization number reduction processing are executed in S4.

  Specifically, an 8-bit image of each of the three RGB colors generated previously is converted into cyan (C), magenta (M), yellow (Y), black (K) (each color) by a known conversion process. Each component is 8 bits / pixel), and the image data of each recording color component is converted into 2 bits (quaternary). The quaternarization is generated by performing dither processing, for example. Note that color conversion processing and quantization processing may be realized by processing using an LUT (Look Up Table) for speeding up the processing. At this time, the dither matrix table to be used is determined according to the mode designated by the user at the time of printing.

  Differences between the tables are mainly for text, for photo printing, for graphics such as graphics, and for example, those giving priority to image quality and those giving priority to compression rate.

  In S4, when conversion to the recording color space and quaternarization are performed, in S5, for example, paper size, paper source selection, resolution, number of gradations, number of bytes in one line, one page Outputs a print condition designation command for designating conditions necessary for printing such as the number of lines.

  Subsequently, in S10, a comparison address setting command for setting a comparison address for each color is output. As a result, a large number of memory blocks MB can be allocated to colors having a large amount of image data.

  Next, in S11, S12, and S13, the compression-coded image data is output together with the command for each color of cyan, magenta, yellow, and black. First, in S11, image data is compression-encoded according to a predetermined compression procedure. In S12, an image data command header specifying the color and size of the image data encoded in S11 is output.

  Next, in S13, the image data encoded in S11 is output, and in S14, it is determined whether or not the processing for each of the cyan, magenta, yellow, and black planes has been completed. If it is determined that all the processing of all color component planes has not been completed, the process returns to S11 to change the color and process the next plane. In this way, when the processing for each of the cyan, magenta, yellow, and black planes is completed, a page end command for designating the end of the page is output in S15, and the processing ends.

  In S3, if the data type is not a page end command, other processing corresponding to the data type (for example, processing corresponding to a printer capability inquiry command) is executed as in S8 and the processing ends.

  A series of commands created as described above is passed to the language monitor 5 via the operating system 2. The communication path from the language monitor 5 to the color printer 10 is logically composed of one command channel and four data channels corresponding to cyan, magenta, yellow, and black colors.

  Whether or not data transfer is possible in each channel is indicated by a status which is a response to the status acquisition command. When the language monitor 5 receives the command, it sends a status request command to the color printer 10 via the USB port driver 6. When the color printer 10 receives the status request command, the color printer 10 transmits the status. The transmitted status is passed to the language monitor 5 via the USB port driver 6.

  The language monitor 5 checks the passed status and transmits a command (data) to be transmitted on a channel for which transmission is permitted. For example, if transmission through the command channel is permitted and there is an untransmitted command other than the image data command such as a printing condition designation command, it is transmitted. In addition, transmission on the data channel corresponding to the black image is permitted, and if there is an untransmitted black image data command, it is transmitted. In this way, the language monitor 5 transmits the command while confirming the status, and continues to transmit until all of the series of passed commands have been transmitted.

  Here, the transmission method outputs all of one color component and then sequentially transmits data of a plurality of color components in an appropriate data amount unit instead of moving to the next color component.

  Next, a specific example of the processing procedure of the language monitor 5 in the first embodiment will be described.

  FIG. 7 is a flowchart illustrating a specific example of a processing procedure of the language monitor 5 according to the first embodiment.

  First, in S31, it is determined whether or not the entire series of commands (including compressed image data) constituting one page has been received. If the entire series of commands composing one page has not been received, it is determined in S32 whether the job has been completed (that is, all the commands for the job have been received). If all the commands for this job have been received, the process ends. If all the commands for the job have not been received, the process returns to S31 and waits for the reception of the entire series of commands constituting one page.

  If it is determined in S31 that the entire series of commands constituting one page has been received, the status of the color printer 10 is requested and acquired in S33. The printer status includes the size of the image data stored in each memory block MB.

  Next, in S34, it is determined whether or not all color data can be stored in each memory block MB. If all the color data can be stored in each memory block MB, in S39, the compression encoded data of each color component is transmitted as a command.

  If it is determined in S34 that all color data cannot be stored, the status of the color printer 10 is requested and acquired in S35. In S36, the presence / absence of unprocessed print data is determined. If there is unprocessed data, the process returns to S35. If it is determined in S36 that there is no unprocessed print data, in S39, the compression encoded data of each color component is transmitted. Within S39, the compressed data that can be transmitted for each color component is transmitted, and after the buffer becomes full, the data for each color component is cut into pieces and transmitted on average as soon as a free area is formed.

  Next, the printing process by the color printer 10 in the first embodiment will be described.

  FIG. 8 is a flowchart showing a processing procedure (mainly reception processing) of the control circuit 16 provided in the color printer 10.

  First, in S21, it is determined whether or not a command has been received, and the command reception is awaited. If it is determined that the command has been received, in S22, it is determined whether or not the received command is a status request command. If the received command is a status request command, in S23, the status is transmitted, and the process returns to S21.

  If the received command is not a status request command in S22, it is determined in S24 whether the received command is a print condition designation command. If the received command is a printing condition designation command, in step S25, the printer engine 15 is instructed to start printing in accordance with the designated printing condition, and the process returns to step S21. This printing condition includes specifying the recording resolution and the paper source.

  If it is determined in S24 that the received command is not a print condition designation command, it is determined in S26 whether or not the received command is a comparison address setting command. If the received command is a comparison address setting command, in S27, the comparison address setting register is set according to the received memory ratio designation command, and the process returns to S21. The four read pointer control circuits 211 to 214 and the four write pointer control circuits 221 to 224 are initialized.

  If the received command is not a comparison address setting command in S26, it is determined in S28 whether the received command is a header portion of an image data command. If the received command is the header portion of the image data command, in S29, the subsequent image data is stored in the memory block MB corresponding to the color of the image indicated by the header portion of the image data command. Thus, the DMA controller 12 is set and transferred, and the process returns to S21.

  When the DMA controller 12 reads the image data following the header portion of the image data command, the DMA controller 12 stores it in the designated memory block MB. When one transfer is completed, the write pointer is updated.

  If the received command is not the header part of the image data command in S28, other commands are processed in S30, and the process returns to S21.

  As described above, when the transfer of the data of each recording color component is completed, the control circuit 16 has each decoding circuit 14Y, 14M, 14C, 14K at a predetermined timing (timing when the recording paper is conveyed to a predetermined position). , The decoding process is started at a timing shifted by a time corresponding to the recording order and the drum interval d. As a result, processed free areas are generated in the memory blocks MB of the respective color components, and the host computer 1 can transfer the data if there is untransferred data.

  According to the first embodiment, a large amount of the memory 13 in the printer can be allocated to color components having a large amount of data, so that a limited memory can be used effectively. Therefore, when the image data of a specific color component becomes large due to the difference in compression rate, it is possible to prevent the data transfer from being in time for the recording speed even with a small amount of memory.

  Also, when reallocating a lot of memory to a specific color, it is realized only by hardware by setting a comparison address in advance, so even if not all recorded data is generated in the host, the data The transfer can be started. As a result, the throughput of printing can be increased.

  In addition, an example in which the dither method is used when the host computer side sets each recording color component 8 bits to a smaller number of bits has been shown. However, not only dither but also an error diffusion method may be used. In the case of error diffusion, the error diffusion coefficient used for error diffusion and the matrix size can be changed to be handled in the same way as a dither matrix.

  Further, although the color printer 10 in the embodiment has been described as recording a gradation image of four gradations (one pixel and two bits), the number of gradations that can be printed is not limited to this, and any gradation number may be used. Also, the quaternarization that is quantized on the host computer 1 side is the same, and it is not always necessary to reduce the number of bits. However, because the recording resolution of recent printers is very high, it is more efficient to reproduce multiple dots in area gradation than to reproduce one dot with multiple levels of density, and the amount of data can be reduced. Desirably, it is desirable to reduce the number of bits of one recording color component as in the above embodiment.

  In the first embodiment, a laser beam printer is used as the printer engine. However, the first embodiment can also be applied to a printer that ejects ink droplets. For example, the present invention can be applied to an apparatus in which a full line head in which ejection nozzles for one scanning line are arranged is prepared for the number of recording color components.

  In addition, since the computer program corresponding to the language monitor 5 is also a part of the printer driver in a broad sense, the computer program composed of both the printer driver 4 and the language monitor 5 can be viewed as a printer driver program.

Also, since the printer driver normally functions by setting a portable computer storage medium such as a CDROM in a computer and copying or installing it in the system, the first embodiment should be understood as a computer-readable storage medium. Can do.

1 is a block diagram illustrating a color printer 10 and a host computer 1 that are Embodiment 1 of the present invention. FIG. 1 is a block diagram illustrating a configuration of a color printer 10 in Embodiment 1. FIG. 1 is a conceptual diagram illustrating a printer engine 15 in Embodiment 1. FIG. FIG. 2 is a conceptual diagram illustrating a scanner unit 301 in the printer engine 15 according to the first embodiment. 2 is a block diagram showing a ring buffer provided in the color printer 10. FIG. 4 is a flowchart showing an operation when the printer driver 4 receives data for one drawing unit from the operating system 2. 6 is a flowchart illustrating a specific example of a processing procedure of the language monitor 5 according to the first embodiment. 3 is a flowchart showing a processing procedure (mainly reception processing) of a control circuit 16 provided in the color printer 10;

Explanation of symbols

1 ... Host computer,
10 ... Color printer,
12 ... DMA controller,
13 ... Memory,
MB1, MB2, MB3, MB4, MB5 ... memory block,
15: Printer engine.

Claims (9)

In a color printer that receives print data and records a color image on a predetermined storage medium,
A reception buffer for receiving and temporarily storing image data compressed and encoded for each of the cyan, magenta, yellow, and black color components;
The reception buffer is pre-divided into first to fifth areas, the first area is assigned to cyan image data, the second area is assigned to magenta image data, and the third area is assigned to yellow. Memory dividing means for allocating image data, allocating the fourth area to black image data, and allocating the fifth area to an arbitrary color after printing data reception starts;
A plurality of decoding means for decoding the received encoded data into image data independently for each of the cyan, magenta, yellow, and black color components;
A color printer comprising: In claim 1,
A received data amount measuring means for measuring the received data amount for each color;
Data amount comparison reference value setting means for presetting a data amount comparison reference value for each color;
Comparing means for comparing the set reference value for data amount comparison with the measured value measured by the received data amount measuring means;
Have
The memory dividing means, after starting the reception data, based on the comparison result by the comparison means, receives the fifth area for the color corresponding to the area that has exceeded the data amount comparison reference value earliest. Color printer characterized by assigning as. In claim 1 or claim 2,
A color printer, wherein each area of the reception buffer assigned to each color component functions as a ring buffer. In a color printer control method for receiving print data and recording a color image on a predetermined storage medium,
A receiving step of receiving image data compressed and encoded for each of the cyan, magenta, yellow, and black color components and temporarily storing them in a receiving buffer;
The reception buffer is pre-divided into first to fifth areas, the first area is assigned to cyan image data, the second area is assigned to magenta image data, and the third area is assigned to yellow. A memory dividing step of allocating image data, allocating the fourth area to black image data, and allocating the fifth area to an arbitrary color after starting reception of print data;
A plurality of decoding steps for decoding the received encoded data into image data independently for each of the cyan, magenta, yellow, and black color components;
A method for controlling a color printer, comprising: In claim 4,
A received data amount measuring step for measuring the received data amount for each color;
A data amount comparison reference value setting step for presetting a data amount comparison reference value for each color;
A comparison step for comparing the set reference value for data amount comparison with the measured value measured by the received data amount measuring means;
Have
In the memory dividing step, after the reception data is started, the fifth region is received in the reception buffer for the color corresponding to the region that has exceeded the data amount comparison reference value earliest based on the comparison result in the comparison step. A method for controlling a color printer, characterized by being assigned as: In claim 4 or claim 5,
A method of controlling a color printer, wherein each area of the reception buffer assigned to each color component is used as a ring buffer. In a control program for a color printer that receives print data and records a color image on a predetermined storage medium,
A receiving step of receiving image data compressed and encoded for each of the cyan, magenta, yellow, and black color components and temporarily storing them in a receiving buffer;
The reception buffer is pre-divided into first to fifth areas, the first area is assigned to cyan image data, the second area is assigned to magenta image data, and the third area is assigned to yellow. A memory dividing step of allocating image data, allocating the fourth area to black image data, and allocating the fifth area to an arbitrary color after starting reception of print data;
A plurality of decoding steps for decoding the received encoded data into image data independently for each of the cyan, magenta, yellow, and black color components;
A control program for a color printer, comprising: In claim 7,
A received data amount measuring step for measuring the received data amount for each color;
A data amount comparison reference value setting step for presetting a data amount comparison reference value for each color;
A comparison step for comparing the set reference value for data amount comparison with the measured value measured by the received data amount measuring means;
Have
In the memory dividing step, after the reception data is started, the fifth region is received in the reception buffer for the color corresponding to the region that has exceeded the data amount comparison reference value earliest based on the comparison result in the comparison step. A control program for a color printer, characterized by being assigned as In claim 7 or claim 8,
A color printer control program, wherein each area of the reception buffer assigned to each color component is used as a ring buffer.

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