JPH1016320A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print coping with either of two printing methods wherein resolution in printing is also different by realizing a second printing method wherein printing is carried out in a second resolution by an input data from outside in addition to a first printing method. SOLUTION: In a printer 10, a print engine part 50 carrying out printing is constituted so as to print in 600dpi resolution. In printing of low resolution, the essential number of pixels is reduced to 1/n in both length and breadth directions by generating a video signal VD making one bit of a bit map data for low resolution correspond to a plurality of pixels with an LSB 38, and the printing of low resolution is realized. Therefore, since an operating state of the print engine part 50 is not necessarily changed according to the resolution, a structure of an apparatus can be simplified. Further, when a PDL data is printed, 600dpi is entirely not necessarily appreciated in preparation of an intermediafe data from a received data and in development from the intermediate data to the bit map data, and the printing can be processed in the same way as conventionally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inputting encoded print data from outside and converting the print data into image data which can be printed at a first resolution. The present invention relates to a printer capable of executing a second printing method of inputting image data that can be printed at a higher resolution of a second resolution from the outside and printing with the image data in addition to the first printing method to be performed.

[0002]

2. Description of the Related Art Conventionally, when printing a document or the like, a printer that receives supply of encoded print data from a host computer, converts the print data into bitmap data internally, and performs printing is known. I have. In recent years,
2. Description of the Related Art Printers (host-based printers) that generate image data composed of bitmap data on the host computer side and perform printing by receiving the supply of the image data are becoming widespread.

The former printing method using a printer is mainly adopted in a so-called character-based operation system, for example, software compatible with DOS, while the latter printing method using a so-called GDI (Graphical Device) is used. Interface), for example, WIND
It is mainly employed in software compatible with OWS (registered trademark; the same applies hereinafter).

[0004]

However, these printers have different printing methods from each other, and the latter printer (host-based printer) does not have a function of converting print data into bitmap data. Printing based on print data created by the corresponding software cannot be executed. On the other hand, the former printer also prints based on print data created by DOS-compatible software,
Printing based on image data created by WINDOWS-compatible software can also be basically executed.
However, when printing based on print data is performed by the former printer, the creation of bitmap data for the page can be started only after the reception of the print data for one page is completed. A memory for storing both data is required, and generally only 300 dpi image data can be handled in order to prevent the memory from having a large capacity.

[0005] When printing is performed on such a printer based on 600 dpi data having a higher resolution than 300 dpi created by WINDOWS-compatible software, 600 dpi image data is simply calculated as a 300 dpi image data. Since the data amount is four times the data amount, there is a problem that printing cannot be performed unless the memory capacity is increased by the same printing method as that at 300 dpi.

The present invention has been made to solve the above problems.
In addition to a first printing method of inputting print data from outside and converting the print data into image data internally and then printing at a first resolution, inputting image data from outside,
It is an object of the present invention to provide a printer capable of realizing a second printing method for performing printing at a second resolution using the image data.

[0007]

According to a first aspect of the present invention, there is provided a printer according to the present invention, wherein first print control means stores received data input from the outside in a receive buffer. At the same time, based on the command data included in the received data, the print data included in the received data is converted into image data that can be printed at the first resolution, and the image data is stored in the image data buffer. When print data for one page is received, the data transfer unit is activated.

On the other hand, when the control is switched by the control switching means from the first print control means to the second print control means, the second print control means transmits received data inputted from the outside to the image data buffer. When the image data stored in the image data buffer exceeds a predetermined amount, the data transfer means is activated. Note that the received data at this time is composed of image data that can be printed at a second resolution higher than the first resolution.

Then, the data transfer means activated by the first print control means or the second control means converts the image data stored in the image data buffer into serial data and supplies the serial data to the print engine unit. Thus, printing is executed by the print engine unit.

The data transfer means controls a line buffer capable of holding image data for one line of pixels corresponding to printing at the second resolution, and controls writing and reading of image data to and from the line buffer. At the time of activation by the first print control means, the image data that can be printed at the first resolution written in the line buffer is replaced with a data number corresponding to the number of pixels used in the second high-resolution print. And a line buffer control means for expanding the line buffer control means.

That is, when printing at the second resolution,
By associating one bit of the image data stored in the line buffer with one pixel, printing at the highest resolution possible with the print engine unit is realized. Low resolution printing is realized by reducing the substantial number of pixels by associating one bit of the image data to be obtained with a plurality of pixels.

Thus, according to the printer of the present invention,
Printing can be executed in accordance with any of the first and second printing methods which differ not only in the data format of the received data but also in the printing resolution. In the printer of the present invention,
When printing at the first resolution, when supplying the image data to the print engine unit, the image data is expanded so as to have a data number corresponding to the number of pixels used for printing at the second resolution. I have.

Therefore, according to the printer of the present invention, it is sufficient that the print engine unit is configured to be capable of printing at the second resolution, and there is no need to switch the operation state of the print engine unit depending on the difference in resolution. The apparatus configuration can be simplified, and even when the print engine unit needs the number of data corresponding to the second resolution, when printing is performed at the first resolution, the image data stored in the image data buffer is stored. Data amount does not increase.

Further, in the second printing method, the image data received from the outside is directly stored in the image data buffer without being stored in the receiving buffer. When data can be received and image data of a predetermined amount or more is accumulated,
The data transfer means is activated to start printing without waiting for the reception of one page, and the image data is received while printing. It is possible to print even if the capacity is larger than the capacity of the image data, and the capacity of the image data buffer can be made smaller than one page of image data at the second resolution.

If the second resolution is n times (where n is an integer) the first resolution, the line buffer control means may control the line buffer control means according to a predetermined read clock. And a read control for outputting an update request signal for requesting an update of the contents of the line buffer each time data reading for one line of pixels corresponding to the second resolution is completed while reading data one bit at a time from Means, write control means for writing the next one line of image data from the image data buffer into the line buffer in accordance with the update request signal, and read control means when starting by the first control means, Data extension means for causing the write control unit to output the write request signal output from the read control means to the write control unit only once every n times, It is possible to further configuration.

Next, in the printer according to the third aspect of the present invention, the image data stored in the image data buffer is used as the image data stored in the image data buffer. The data is transferred to the line buffer via data restoration means for restoring possible data.

Therefore, in the printer according to the present invention, since the image data buffer stores the image data compressed, the capacity of the image data can be further reduced. Next, in the printer according to the fourth aspect, the data restoration unit is configured by hardware. Therefore, according to the printer of the present invention, compressed image data can be restored at high speed, and high-speed printing can be performed.

Next, in the printer according to the fifth aspect, the control switching means detects a command input from the outside,
The control is switched according to this command. Therefore, according to the printer of the present invention, the first printing method and the second printing method can be automatically switched under the control of a host computer or the like that supplies print data and image data to the printer.

Next, in the printer according to the present invention, the second print control means uses the reception buffer as a part of the image data buffer, thereby providing the buffer expansion means for expanding the image data buffer. Have.
Therefore, according to the printer of the present invention, the buffer capacity of the entire apparatus can be expanded by the size of the reception buffer.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. The printer system 10 of the present embodiment has
As shown in FIG.
And a laser printer 30 that receives data from the host computer 20 and executes printing. The host computer 20 and the laser printer 30 are electrically connected via a parallel data transmission / reception cable (here, a Centronics cable).

The host computer 20 supports both a character-based first OS (specifically, DOS) and a second OS equipped with GDI (specifically, WINDOWS) for printing. Outputs data.
Under DOS, it is configured to output PDL (page description language) type print data and command data (hereinafter, “PDL output”,
"PDL data" etc.). Specifically, PCL of HP (Hewlett-Packard), Po of Adobe
St Script, Canon's LIPS, and Epson's ESC / P (both are trade names) are known. Then, under WINDOWS, it is configured to output bit-mapped image data and command data (hereinafter referred to as “HBP output”, “HBP data”, etc.). Here, the data obtained by further compressing the bit-mapped image data is supplied to the laser printer 30.

In the PDL system, the print data itself is irrelevant to the printing resolution. However, by specifying the resolution from among 300 dpi, 200 dpi, and 150 dpi by the command data, the laser printer 30
In the HBP method, on the other hand, the image data itself corresponds to the resolution of printing, and the host computer 2
0 normally outputs 600 dpi, but 30
Image data having a resolution of 0 dpi, 200 dpi, and 150 dpi can also be output.

Next, the laser printer 30 has a print engine unit 50 including a printing mechanism for printing in an electrophotographic system, a paper feeding mechanism, and the like. This print engine unit 50
Although it is configured to print at 600 dpi, it is the same as an existing laser printer, and a detailed description thereof will be omitted.

A control unit which receives data to be printed from the host computer 20, converts the data into a video signal VD and supplies the video signal VD to the print engine unit 50 includes a CPU 31 as a control center, as shown in FIG. A ROM 32 storing a control program, a RAM 33 functioning as a ring buffer, a DMA controller 34 controlling a write pointer of the RAM 33 to write data into the RAM 33, and controlling a read pointer of the RAM 33 to read data from the RAM 33 And the compressed image data transferred from the RAM 33 by the DMA controller 35,
A decompression circuit 37 for developing bitmap data,
A line scan buffer (LSB) 38 for converting bitmap data supplied from the RAM 33 by the controller 36 or via the decompression circuit 37 to a video signal of serial data and supplying the video signal to the print engine unit 50 is provided.

CPU 31 and DMA controller 34
Are configured to receive data from the host computer 20 via an interface 52 for a Centronics cable, and the CPU 31 and the DMA controller 34 have strobes for controlling input / output of data via the interface 52. The signal line STB is connected, and further, various other control lines CTL are also connected to the CPU 31.

A latch 39 to which a command can be written from the host computer 20 is provided between the CPU 31 and the interface 52. When a command is written to the latch 39, an interrupt is issued to the CPU 31. Has been to happen. On the other hand, the DMA controller 34 is either a Centronics data compatible (Centronics is a company name) or an ECP mode (IE
EE 1284).

Decompression circuit 37 and DMA controller 36
When the write request signal WQ is input from the LSB 38,
LS bitmap data for one line according to the resolution
It is configured to write to B38 and output a write end signal WE to LSB 38 when the writing is completed.

Also, the DMA on the write side is
By exchanging pointer information between the controller 34 and the two DMA controllers 35 and 36 on the read side, the DMA controllers 35 and 36 do not read beyond the write pointer, and the DMA controller 34 So that it cannot be written over.

The DMA controllers 34, 35, 3
6, the decompression circuit 37, the LSB 38, and the latch 39 are constituted by a single application-specific semiconductor integrated circuit (ASIC). Next, FIG. 2 is a block diagram illustrating an internal configuration of the LSB 38.

As shown in FIG. 2, the LSB 38
SRAM 40 for storing one line of bitmap data supplied from controller 36 or decompression circuit 37
A read clock generation circuit 42 for generating a read clock RCK for reading bitmap data one bit at a time from the SRAM 40;
Read address generation circuit 44 for generating read address RAD when reading bitmap data from RAM 40
And a vertical enlargement circuit 46 for enlarging the bitmap data in the sub-scanning direction, that is, on the print image in the vertical direction by controlling the writing of the bitmap data to the SRAM 40 in accordance with the resolution selection signal SEL. By controlling the operation of the read address generation circuit 44 in accordance with the selection signal SEL, the read address generation circuit 44 includes a horizontal enlargement circuit 48 for enlarging the bitmap data in the main scanning direction, that is, on the print image in the horizontal direction.

When the permission signal EN is input from the vertical enlargement circuit 46, the read clock generation circuit 42 synchronizes with the beam detection signal BD supplied from the print engine unit 50, and also outputs the read clock signal from the print engine unit 50. The supplied video clock VCK is supplied to the SRAM 40 as a read clock RCK, and the read clock RCK is set to 512.
When no data is output, it is determined that data reading for one line has been completed, and the empty signal EMP is sent to the vertical enlargement circuit 46.
Is configured to be output. Note that the beam detection signal BD is a laser beam for forming an electrostatic latent image on the photosensitive drum in the print engine unit 50, which is periodically output each time the photosensitive drum is scanned once. The video clock VCK is a clock signal output from the print engine unit 50 in synchronization with the beam detect signal BD.

The read address generation circuit 44
Bit counter, the count value of which is
40, and a count clock GCK from the horizontal enlargement circuit 48.
, And when the beam detect signal BD is input, the count value is reset.

Further, when the setting of the resolution selection signal SEL is 600 dpi, the vertical enlargement circuit 46 outputs the empty signal BD as it is as the write request signal WQ, and the write end signal WE as it is as the enable signal EN. , To the read clock generation circuit 42. Further, when the setting of the resolution selection signal SEL is 300 dpi, the writing request signal WQ is output only once every time the empty signal EMP is input twice, and similarly, the setting of the resolution selection signal SEL is set to 200 dpi. At one time, the write request signal WQ is output only once each time the empty signal EMP is input three times, and at 150 dpi every time the empty signal EMP is input four times. When the write request signal WQ is not output despite the input of the empty signal EMP, the write end signal WE
Is configured to output the permission signal EN even if the input is not input.

When the setting of the resolution selection signal SEL is 600 dpi, the horizontal enlargement circuit 48 outputs the video clock VCK as it is to the read address generation circuit 44 as the count clock GCK, and the setting of the resolution selection signal SEL is 300 dpi. , The video clock VCK divided by two, the 200 clock divided by three, and the 150 clock divided by four are counted clocks GCK.
It is configured to output as.

In the LSB 38 configured as described above, when the setting of the resolution selection signal SEL is 600 dpi, 5120-bit bitmap data is stored in the SRAM 40 as data for one line as shown in FIG. 3A. You. Then, the read address RAD is updated each time the read clock RCK is input, so that S
Different bitmap data is read from the RAM 40 for each read clock RCK, and the empty signal E
Since MP is output as it is as the write request signal WQ, every time data is read from the SRAM 40 by the number of pixels (5120 bits) for one line of the print image, SR is output.
The contents of AM 40 are updated. As a result, in a print image generated based on the video data VD output from the LSB 38, 1 bit corresponds to 1 bit of the bitmap data.
The pixels correspond to each other, and printing is performed at 600 dpi, which is the resolution of the print engine unit 50.

The setting of the resolution selection signal SEL is 30
When it is 0 dpi, as shown in FIG. 3B, 2560 bits,
That is, half the bitmap data at the time of 600 dpi is stored. When the read address RCK is updated only once every time the read clock RCK is input twice, the same bitmap data is continuously read twice from the SRAM 40, and the empty signal is output. E
Since the MP is output only once every two times as the write request signal WQ, the contents of the SRAM 40 are updated every time two lines of data are read with the same contents. As a result, in the print image, 4 (2 × 2) pixels correspond to one bit of the bitmap data, which substantially corresponds to a reduction in the number of pixels in both the vertical and horizontal directions to 、.
Printing is performed at half of the resolution achievable by the print engine unit 50, that is, at 300 dpi.

Similarly, when the resolution selection signal SEL is set to 200 dpi, the SRAM 40 stores 1706 bits, that is, 600 dpi, as shown in FIG.
1/3 of the bitmap data is stored, and the print image is 9 (3 × 3) for one bit of the bitmap data.
3) Pixels correspond to each other, which substantially corresponds to a reduction in the number of pixels in both the vertical and horizontal directions to 1/3, so that the resolution that can be realized by the print engine unit 50 is 1/3, that is, 200 dpi.
Will be printed. Also, the resolution selection signal S
When the setting of EL is 150 dpi, as shown in FIG.
1/4 bitmap data at the time of 0 dpi is stored,
The print image is one for one bit of the bitmap data.
6 (4 × 4) pixels correspond to the fact that the number of pixels is substantially reduced to ４ in both the vertical and horizontal directions, so that the resolution achievable by the print engine unit 50 is ４, that is, 15
Printing is performed at 0 dpi.

Next, the format of data supplied from the host computer 20 to the laser printer 30 via the interface 52 will be described. The host computer 20 outputs the PDL under the DOS, and then outputs the HBP under the WINDOWS.
Thereafter, the configuration is such that PDL output can be performed again. In this case, the host computer 20 outputs a PD as schematically shown in FIG.
Following the L data, HBP data is output, and further PDL data is output. A print mode shift command indicating that the print mode is shifted from PDL to HBP is inserted between the first PDL data and the HBP data, and between the HBP data and the second PDL data. Indicates that a print mode return command indicating that the print mode is restored from the HBP to the PDL is inserted.

Here, the HBP data will be described in more detail. As shown in FIG.
At the top are various commands. This command includes a resolution specification command for specifying the resolution of the image data to be transmitted and a data number specification command for specifying the number of data of the image data to be transmitted. Is stored. Following this image data, a similar data number designation command and image data, or a page feed (form feed: FF) command indicating the end of one page are stored. Furthermore,
When there is data for the next page, the same data as described above continues.

Next, the RAM 33 of the laser printer 30 will be described in detail. First, when PDL data is received, as shown in FIG. 5A, a reception buffer RB (4 KB) for storing reception data from the host computer 20 and a reception buffer RB are stored in the RAM 33. Intermediate code buffer CB (426 KB) for storing intermediate data created on the basis of the command data and the print data, and a band buffer BB (62 KB) for storing bitmap data obtained by expanding the intermediate data. ) And a work area WA (20 KB) used in various processes performed by the CPU 31 are set.

On the other hand, when HBP data is received, FIG.
As shown in (B), an extension buffer EB for storing the compressed image data received from the host computer 20
(492 KB) and the above-described work area WA are set. That is, in an area other than the work area WA, there is no distinction between the reception buffer RB, the intermediate code buffer CB, and the band buffer BB, and all of them are extended buffers EB.
(492 KB).

Next, the specific contents of the data reception control processing performed by the CPU 31 of the laser printer 30 will be described with reference to the flowcharts shown in FIGS. This process is started by an interrupt generated when the host computer 20 writes a command to the latch 39.

When this processing is started, first, at S10
Then, the command written in the latch 39 by the host computer 20 is read, and in a succeeding step S20, it is determined whether or not the command is a transmission request from the host computer 20. If the command is not a send request,
The process proceeds to S30, and after executing the corresponding process according to the command, the process ends. On the other hand, if the command is a transmission request, the process proceeds to S40, where the buffer in the RAM 33 is set for PDL data, and in S50, the data from the host computer 20 is transferred to the reception buffer RB one byte at a time. The DMA controller 34 is set and activated.

In S60, the received data written in the receiving buffer RB by the DMA controller 34 is read out one byte at a time. In S70, it is determined whether or not the read out received data is a print mode shift command.
If it is not a print mode shift command, the process shifts to S80. At S80, the received data read at S60 is
It is determined whether the received command is a page break command. If not, it is determined that the received data is print data or command data for obtaining intermediate data from print data. After creating the intermediate data from the print data and storing it in the intermediate code buffer CB according to the instruction, the process returns to S60 and returns to S60 to S60.
90 is repeated.

On the other hand, if it is determined in S80 that the reception data read from the reception buffer RB is a page break command, the flow shifts to S100 to output a resolution selection signal SEL to the LSB 38, and then to S110. After starting the bitmap data creation process, the process proceeds to S120.

The resolution (300 dpi / 200 dpi / 150) is included in the command data interpreted in S90.
dpi) is included, and S
At 100, a resolution selection signal SEL is output according to the designation. The bitmap data creation process is a process that is executed separately from the present process. The one-page intermediate data stored in the intermediate code buffer CB is sequentially converted into bitmap data and stored in the band buffer BB. The bitmap data stored in the band buffer BB is stored in accordance with the write request signal WQ from the LSB 38.
D is transferred to the LSB 38 for each line (the number of data differs depending on the specified resolution as described above).
The processing for setting and starting the MA controller 36 is executed. This processing is performed by the band buffer BB
When the transfer of the bitmap data from the to the LSB 38 is completed, the DMA controller 36 is stopped and the processing is terminated.

In S120, it is determined whether or not the reception buffer RB is empty. If there is unprocessed reception data in the reception buffer RB, the process returns to S60, and the above-described processes S60 to S60
Step 110 is repeated, and if there is no unprocessed reception data in the reception buffer RB, the process proceeds to S130 and the DMA controller 3 set to transfer the reception data from the host computer 20 to the reception buffer RB.
4 is stopped and the present process is terminated.

That is, in the processing of S10 to S130, when there is a transmission request from the host computer 20, the setting is made so that the reception data from the host computer 20 is stored in the reception buffer RB, and the reception data read from the reception buffer RB is Unless the command is a print mode shift command, P
Assuming that the DL data is to be received, intermediate data is created based on the received data (command data and print data) and stored in the intermediate code buffer CB. The command includes a command for specifying a resolution at the time of printing, and intermediate data corresponding to the resolution is created. When one page of intermediate data is stored in the intermediate code buffer CB (a page break command is received), the intermediate data is sequentially developed into bitmap data and stored in the band buffer BB and stored in the band buffer BB. The bitmap data is transferred to the write request signal WQ from the LSB 38.
Are sequentially transferred to the LSB 38 in accordance with.

Then, the LSB 38 converts the bitmap data into a video signal VD while expanding the bitmap data in accordance with the designation of the resolution selection signal SEL, and the print engine 50 executes printing based on the video signal VD. A print image at the specified resolution is obtained.

Next, at S70, the reception buffer RB
If the data read from is a print mode shift command, the process proceeds to S140 and the DMA controller 34
Is stopped, and in subsequent S150, the reception buffer RB
Interpret all data already stored in. That is, at this time, since the data stored in the reception buffer RB is HBP data, the resolution specifying command and the data number specifying command are interpreted.

At S160, if the bitmap data creation process started at S110 is running, the process waits for the end, that is, waits until all the bitmap data of the band buffer BB is transferred to the LSB 38. RAM
33 is reset for HBP data reception, and in S170, the DMA controller 34
It is set so that the received data from 0 is transferred to the extension buffer EB and activated. If there is already received image data before the DMA controller 34 is stopped in S140, the transfer is performed by subtracting the number of received image data from the number of data specified by the data number designation command. The DMA controller 34 is set to perform the operation.

At S180, the DMA controller 3
It is determined whether or not the extension buffer EB is full by the data transfer of No. 4, and if image data can still be stored, the process proceeds to S190. In S190, the DMA controller 34 determines whether or not the transfer of the specified number of data has been completed and stopped, and if not stopped, it is determined that the data is being transferred, and the process returns to S180.
Step 190 is repeated.

On the other hand, if it is determined in S190 that the DMA controller 34 has stopped, it is determined that the transfer of the specified number of data has been completed, and the flow shifts to S200.
A command is received from the host computer 20 via the latch 39. At S210, it is determined whether the command received at S200 is a page break command.
If it is not a page break command, the DMA controller 3 determines that the data number designation command has been received and shifts to S220, and transfers the received data to the extension command EB by the number of data designated by the data number designation command.
After setting and starting 4, the process returns to S180.

If it is determined in step S210 that the received command is a page break command, the flow advances to step S230 to select a resolution for the LSB 38 in accordance with the content of the resolution designation command interpreted in step S150. Signal SEL
Then, in S240, the image data stored in the extension buffer EB is transferred to the decompression circuit 37 so that D
After setting and activating the MA controller 35, the process proceeds to S310. At this time, the decompression circuit 37 decompresses (decompresses) the image data which has been subjected to the data compression into bitmap data, and according to the write request signal WQ from the LSB 38, the bitmap data for one line corresponding to the designated resolution. Transfer the data to LSB 38.

On the other hand, at S180, the extension buffer E
If it is determined that B is full, the process proceeds to S250, where a resolution selection signal SEL is output in exactly the same way as in S230.
After setting and activating the A controller 35, the process proceeds to S270.

In S270, the DMA controller 34
Determines whether the transfer of the designated number of data has been completed and stopped, and if not stopped, repeats S270 and waits until the DMA controller 34 stops. If it is determined in S270 that the DMA controller 34 has stopped, the process proceeds to S280 and proceeds to S200.
In the same manner as in the above, a command from the host computer 20 is received via the latch 39, and in subsequent S290, it is determined whether or not the received command is a page break command.
And if the received command is not a page break command,
Assuming that the data number designation command has been received,
00, the DMA controller 34 is set and activated so that the received data is transferred to the extension command EB by the number of data designated by the data number designation command, and then the process returns to S270.

On the other hand, if it is determined in S290 that the received command is a page feed command, the DMA controller 35 determines the number of remaining data to be transferred to the decompression circuit 37 by D.
After setting in the MA controller 35, the process proceeds to S310. In S310, the host computer 2 is stored in the latch 39.
Judge whether the command from 0 is written,
If the command has not been written, the process ends as it is. If the command has been written, the process shifts to S320 to receive the command.

In the following S330, the received command is
It is determined whether the command is a print mode return command or not.
Assuming that the data is received, the process proceeds to S340,
After receiving the resolution designation command and the data number designation command, the process proceeds to S350, and sets the DMA controller 34 to transfer the received data from the host computer 20 to the extension buffer EB by the number of data designated by the data number designation command. , After the start, return to S180, S1
The processing from 80 to S350 is repeatedly executed.

If it is determined in S330 that the received command is a print mode return command, the process proceeds to S36.
0, whether the extension buffer EB is empty, that is, the decompression circuit 37 by the DMA controller 35
It is determined whether or not the data transfer has been completed. If the extension buffer EB is not empty, S360 is repeatedly executed to wait, and if it is determined that the extension buffer EB is empty,
The process proceeds to S40, and thereafter, S40 to S13 described above.
A process of receiving and printing the PDL data of 0 is executed.

That is, in the processing of S140 to S350, only the image data of the data received from the host computer 20 is stored in the extension buffer EB, and when the page break command is received or the extension buffer EB becomes full, the extension The transfer of the image data from the buffer EB to the decompression circuit 37 is started.

Then, the decompression circuit 37 expands the image data into bitmap data and transmits the expanded bitmap data to the write request signal WQ from the LSB 38.
The LSB 38 converts the bitmap data into a video signal VD while expanding the bitmap data in accordance with the specification of the resolution selection signal SEL, as in the case of the PDL. By executing printing based on the signal VD, a print image with the designated resolution is obtained.

That is, the HBP can print at a resolution of 600 dpi. In this case, when compared with a case where the resolution is 300 dpi (the highest resolution of the PDL), it is simply calculated and four times as much data is required. Originally, the storage capacity of the RAM 33 is set so as to store one page of intermediate data when the resolution is 300 dpi in PDL. Therefore, when the resolution is 600 dpi in HBP, the storage capacity of one page is stored in the extension buffer EB. There is a case where the extension buffer EB becomes full without storing image data. Therefore, in this case, even if data for one page cannot be stored, printing is started and reception is continued at the same time. Normally, the speed at which data is transferred from the host computer 20 to the extension buffer EB is
Since the speed of transfer from the extension buffer EB to the decompression circuit 37 is faster, the amount of image data stored in the extension buffer EB gradually decreases, but all data is read out by the end of reception of one page. The data transfer speed is set so as not to be lost.

For example, the image data stored in the extension buffer EB is compressed to about half that of the bitmap data, and the transfer from the host computer 20 to the extension buffer EB is performed at 200 KB / s. Assuming that the video signal VD is supplied to the print engine unit 50 at 6 Mbps (750 KB / s), image data is read from the extension buffer EB at approximately 380 KB / s and transferred to the decompression circuit 37. Will be. At this time, the data stored in the extension buffer EB is about 180
The extension buffer EB is emptied in about 2.7 (492/180) seconds because it decreases at a rate of (380-200) KB / s. Actually, during printing, the DMA controller 35 occupies about 20% of the entire time, so that 2.7 × 0.
8 = 2.16 seconds.

In other words, in this case, the amount of data per page is 492 KB data stored in the extension buffer EB at the start of printing and approximately 430 KB data receivable in 2.16 seconds. If it is about 920KB (1.8MB when converted to bitmap data),
Can be printed.

As described above, in the printer system 10 of the present embodiment, the print engine unit 50 for executing printing
Is configured to print at a resolution of 600 dpi,
When low-resolution (1 / n of 600 dpi) printing is performed, the LSB 38 generates a video signal VD in which one bit of the low-resolution bitmap data corresponds to a plurality of (n × n) pixels. Thus, the substantial number of pixels is reduced to 1 / n in both the vertical and horizontal directions, thereby realizing low-resolution printing.

Accordingly, the printer system 10 of the present embodiment
According to this, it is not necessary to switch the operation state of the print engine unit 50 depending on the resolution, so that the apparatus configuration can be simplified. Also, when printing PDL data, a conventional printer which only prints PDL data without having to be conscious of 600 dpi at all when creating intermediate data from received data and developing intermediate data into bitmap data. And can be processed in exactly the same way.

Further, in the printer system 10 of the present embodiment, the intermediate data and the HBP
At the time of data printing, data such as compressed image data is stored in the intermediate code buffer CB or the extension buffer EB in a form compressed in comparison with the bitmap data.
When the data is transferred to the LSB 38, it is developed into bitmap data.

Accordingly, the printer system 10 of the present embodiment
According to the method, the buffer capacity, that is, the storage capacity of the RAM 33 can be greatly reduced as compared with the case where the bitmap data is stored in the buffer. Further, in the printer system 10 of the present embodiment, when printing the HBP data, all the areas other than the work area WA on the RAM 33 are used as the extension buffer EB, so that the extension buffer E
B is secured to the maximum, and the expanded buffer EB stores the image data compressed as described above, so that the storage capacity of the RAM 33 (51
Even if 2 KB) is small, high-resolution (600 dpi) printing can be performed.

As described above, in the printer system 10 of this embodiment, the printing method and the PDL having different resolutions are used.
Since both printing using data and printing using HBP data can be executed, when DOS and WINDOWS are used together on the host computer 20, printing can be performed arbitrarily from any software. Can be.

Further, on the host computer 20 side,
It is only necessary to provide a dedicated printer driver for compressing bitmap data generated by software operating under the WINDOWS environment and supplying the compressed data to the laser printer 30, and a printer driver for PDL data operating under the DOS environment is included in the printer driver. Since there is no need to make any changes, the DOS-compliant software resources accumulated so far can be effectively used.

In the above embodiment, the intermediate code buffer CB and the extension buffer EB correspond to the image data buffer of the present invention. When processing PDL data,
Bitmap data creation processing, DMA controller 3
6, the band buffers BB and LSB 38 correspond to data transfer means. On the other hand, when processing HBP data,
The controller 35, the decompression circuit 37, and the LSB 38 correspond to data transfer means. Of these, the bitmap data creation processing and decompression circuit 37 corresponds to data restoration means. Further, S40 to S130 are first control means, and S160 to S130
350 corresponds to the second control means, S70 and S330 correspond to the control switching means, and S140 to S170 correspond to the buffer expansion means. Further, the SRAM 40 corresponds to a line buffer, the read clock generation circuit 42 and the read address generation circuit 44 correspond to read control means, and a portion for transferring data to the LSB 38 by the DMA controller 36 and the decompression circuit 37 is a write control. A vertical enlargement circuit 4
6 and the horizontal enlargement circuit 48 correspond to the data extension means.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. . For example, in the above embodiment, a system in which one host computer performs PDL output and HBP output is described. However, a network system in which a computer that performs PDL output and a computer that performs HBP output is connected to one printer It is needless to say that the present invention may be applied to the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a host-based printer system according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of a line scan buffer according to the embodiment.

FIG. 3 is an explanatory diagram illustrating an operation of a line scan buffer in the embodiment.

FIG. 4 is an explanatory diagram showing an output on the host side in the embodiment.

FIG. 5 is a diagram illustrating an example of PDL data printing and H
FIG. 3 is an explanatory diagram illustrating a configuration of a RAM when BP data is printed.

FIG. 6 is a flowchart illustrating the content of a reception control process on the printer side in the embodiment.

FIG. 7 is a flowchart illustrating reception control processing on the printer side in the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Printer system 20 ... Host computer 30 ... Laser printer 31 ... CPU 32 ...
ROM 33 RAM 34, 35, 36 DMA controller 37 Decompression circuit 38 LSB 39 Latch
Reference Signs List 40 SRAM 42 Read clock generation circuit 44 Read address generation circuit 46 Vertical enlargement circuit 48 Horizontal enlargement circuit 50 Print engine unit 52 Interface

Claims (6)

[Claims] A receiving buffer for storing command data and encoded print data; an image data buffer for storing image data corresponding to a printing resolution; and an image stored in the image data buffer. A data transfer unit that converts data into serial data and supplies the data to a print engine unit that executes printing, and stores received data including command data and print data input from the outside in the reception buffer, The print data is converted into image data printable at a first resolution based on the command data and stored in the image data buffer. When one page of print data is received, the data transfer unit is turned on. And a first print control unit that starts up, externally inputs print data, and internally stores the print data in image data. A printer capable of executing a first printing method of performing printing at a first resolution after conversion to a second resolution capable of printing at a second resolution higher than the first resolution and input from outside The received data including the image data is stored in the image data buffer,
A second print control unit for activating the data transfer unit when the image data stored in the image data buffer exceeds a predetermined amount; and one of the first print control unit and the second print control unit. And control switching means for switching control to: a line buffer capable of holding image data for one line of pixels corresponding to printing at the second resolution; and In addition to controlling the writing and reading of the image data, the image data that can be printed at the first resolution written in the line buffer is written into the second buffer when the first printing control unit starts up. Line buffer control means for expanding the number of data according to the number of pixels used in high-resolution printing, in addition to the first printing method, Receives image data printer, characterized in that the can execute the second printing method for printing in the second resolution by the image data. 2. The method according to claim 1, wherein the second resolution is n times (where n is an integer) the first resolution, and the line buffer control means continuously outputs one bit at a time from the line buffer in accordance with a predetermined read clock. Reading control means for reading out data and outputting an update request signal for requesting an update of the contents of the line buffer each time data reading of one line of pixels corresponding to the second resolution is completed; Write control means for writing the next one line of image data from the image data buffer to the line buffer in accordance with the update request signal, and the same bit is set to n by the read control means at the time of activation by the first control means. And the write request signal output from the read control means is input to the write control unit only once every n times. The printer according to claim 1, characterized in that it is configured and the data expansion means, the. 3. An image data stored in the image data buffer, wherein data compressed is used as the image data stored in the image data buffer, and the image data stored in the image data buffer is restored to a printable data. 3. The printer according to claim 1, wherein the data is transferred to the line buffer via a means. 4. The printer according to claim 3, wherein said data restoration means is constituted by hardware. 5. The control switching means according to claim 1, wherein the control switching means is configured to detect a command input from the outside and switch the control according to the command.
A printer according to claim 4. 6. The image processing apparatus according to claim 1, wherein the second print control unit includes a buffer expansion unit that expands the image data buffer by using the reception buffer as a part of the image data buffer. A printer according to any one of claims 1 to 5.