JPH0784073B2 - Printing control system for personal computer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a laser beam printer (hereinafter abbreviated as LBP).
The present invention relates to a personal computer using a page printer as a printing device or a hard copy output device, and more particularly to a print control system for a personal computer capable of high-speed hard copy at low cost.

[Prior Art] Conventionally, a page printer typified by LBP has been used as a printing device that cannot perform printing on the next line by pausing during printing and printing only on a page-by-page basis. Are known.

In addition to LBP, page printers include LED printers that use light emitting diodes, LCX printers that use liquid crystal shutters, and the like.

For such a page printer, for example, as described in Nikkei Electronics magazine April 8, 1985 issue (No. 366), pages 135 to 157, one page of image data is stored in the page printer. Bit map memory (frame memory), character map memory that stores the character code sent from a personal computer (hereinafter abbreviated as personal computer), font memory (character generator) that stores the font corresponding to the character code, page printer as a whole It is equipped with a processor that controls the.

The personal computer side also has a memory for storing image data and a memory for storing character codes, and these images and character codes are connected to a personal computer and a page printer through a communication cable. That is, RS-232C
Characters are transferred as character code signals and graphic images are transferred as image signals through interfaces such as and Centronics.

[Problems to be Solved by the Invention] In the above conventional technique, a frame memory, a character map memory, a character generator, etc. are required for both a personal computer and a printer, so that the entire personal computer system becomes expensive, and only an image signal can be transmitted at high speed There was a problem such as being unable to transfer.

An object of the present invention is to provide a print control system for a personal computer that is inexpensive and can perform high-speed data transfer.

[Means for Solving Problems] In order to achieve the above object, the present invention provides a print memory for storing image data in a print control system of a personal computer having a page printer as a printing apparatus, and a print memory for the print. Writing means for writing an image in the memory; reading means for reading out the image data in the printing memory at least at the printing speed of the page printer; and transfer speed of the read image data to the page printer. And a transfer speed control means for matching the printing speed of the page printer.

The transfer speed control means has a line buffer for at least one line, and can output the image data for each line from the line buffer in synchronization with a horizontal synchronizing signal from the page printer.

The writing means can develop an image of a character created by using the character generator in the personal computer in the printing memory.

The writing means can write the graphic image created by the CRT controller in the personal computer into the printing memory.

Further, the printing memory can be shared with the frame buffer in the personal computer.

[Operation] In the present invention, the capacity of the page printer memory connected to the bus of the personal computer is equal to or larger than the number of recording pixels of the page printer, and characters, tables, figures, etc. are used as image data for the page printer memory. Remember. Since the page printer can stop the data only in page units and uses the video interface, which is a data transfer method peculiar to the page printer, is the speed of reading image data from the page printer memory equal to the average transfer speed of the page printer? Alternatively, the speed is set farther than that, and a data buffer such as a memory is used to match the read image data with the transfer speed of the page printer.

That is, a frame memory, which is a printing memory conventionally provided in a page printer, is provided in a personal computer, and characters, tables, figures, etc. are developed as image data in the personal computer and stored in the printing memory and stored in the page printer. Data transfer is performed by first transferring from the printing memory to a data buffer having a capacity larger than at least one line of the page printer, storing the data equal to or faster than the data transfer speed of the page printer, and storing the data stored in the data buffer. Transfer the page printer at the same transfer rate.

Since the printing memory can be shared with the frame memory in the personal computer, and the character generator in the personal computer can be used, an inexpensive personal computer system can be configured as a whole. Also,
Since the image data is transferred to the page printer at a speed matching its operating speed, the maximum printing speed is not impaired.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3. In this embodiment, LBP will be described as a page printer.

The inside of the personal computer 1 is roughly classified into a control unit 2 for controlling the entire system, an LBP memory 3, a writing unit 4 for writing an image in the LBP memory 3, and a speed equal to or faster than the speed of the LBP 7. Is constituted by the reading means 5 for reading from the LBP memory 3, the transfer speed control means 6 for adjusting the data read from the LBP memory 3 to the transfer speed to the LBP 7, and the personal computer 1 and the LBP 7 having a video interface. A personal computer system is configured by connecting.

As the details of the present embodiment, the control unit 2 includes the CPU 8, and the CPU 8, the data bus 9, the address bus 10, and the control line 11.
It is composed of the main memory 12 connected by. Writing means 4
Is a character generator (CG) 13, CRT controller 1
Composed of 4 mag. The read means 5 is composed of a direct memory access controller (DMAC) 15, and the transfer rate control means 6 is a high power output buffer 16, a FIFO (first in first out buffer) 17, an oscillation circuit 18, a counter 19, and an RS flip-flop 20. , AND gate 21, counter 2
2. A parallel / serial conversion circuit 23, a high power output buffer 24, etc.

The LBP memory 3 needs to have a storage capacity for at least one page. In this embodiment, LBP7 and a resolution of 400 DPI (Dot Per) are used.
Inch) and recording size A4 were used, so an additional memory of 2 Mbytes was used, and this was connected to the control unit 2 and other things via the data bus 9, address bus 10 and control line 11 in the personal computer. . This LBP memory 3 can also be used as a frame buffer memory of the personal computer itself.

Operation of the system of FIG. 1 will now be described with reference to the flow chart of FIG. 2 and the timing diagram of FIG.

The image data is written to the LBP memory 3 under the control of the control unit 2 by developing the character data of CG4 into image data and writing it, or writing the image data drawn by the CRTC14, or an external device. The data input from is written. When the writing for one page is completed in this way, the DM which is the reading means is next.
AC5 is initialized by the control unit 2 to check whether the LBP7 is ready. If it is ready, one page of data is continuously transferred to the transfer speed control means 6 as about 8 bit information.
The data is read at a frequency of about 0 KHz. After this reading is completed, the control unit 2 checks whether the same copy is to be copied on a plurality of pages or to record the next page. When copying a plurality of pages, the DMA initialization is performed. When the next page is recorded, the LBP is used. The operation is performed again from the data writing to the memory 3.

The transfer rate control means 6 transfers the 8-bit data (A) and (B) (only 2 bits out of 8 bits are illustrated in FIG. 3) continuously read by the DMAC 15 via the buffer 16 to the FIFO 17. Then, the speed of 8-bit data is converted so that one line of data is sent to LBP7 within the effective recording range of LBP7 according to the vertical sync signal (C) and horizontal sync (D) output from LBP7. , 8 bits (F) (G)
Is converted into a 1-bit video interface signal (I) by the parallel / serial conversion circuit 23, and is converted via the buffer 24.
It is designed to be sent to LBP7. The oscillator circuit 18
A clock having a pixel frequency of LBP7 is oscillated, and in this embodiment, a clock of 3.25 MHz is oscillated. Also, L
The signal (E) that indicates the effective recording range of BP7 is LBP.
The horizontal synchronizing signal (D) of 7 is used as a reference (that is, the counter 19 is reset) and the clock of the oscillation circuit 18 is counted.
It is created by counting at 19 (for example, setting the RS flip-flop 20 at a count of 128 and resetting at a count of 2928). Further, a signal (E) indicating the recording effective range of LBP7 and the clock which is the output of the oscillation circuit 18 are logically ANDed by the AND circuit 21, and the counter 22 divides this by 1/8 to produce a signal (H )I have to. The parallel data acquisition from the FIFO17 to the parallel / serial converter 23 is
Parallel / serial converter that performs according to the signal (H)
The serial data output from 23 is performed in accordance with the output of the AND circuit 21 so that it is output as data matching the speed of LBP7. Here, the FIFO 17 cannot stop the data in the middle of one page, and cannot empty the data while transferring the data to the LBP7. Therefore, the data transfer time for one row of data sent from the DMAC15 is T ₁ , LB
When P7 of one period of the horizontal synchronizing signal and T _2, in the present invention T ₁
Since ≦ T ₂ , the capacity of the FIFO memory 17 needs to be at least one row or more. In this embodiment, this memory capacity is 512 Kbytes, but the capacity for one page is not required. Therefore, according to the present embodiment, recording can be performed in the LBP7 with a small circuit configuration.

FIG. 4 shows another embodiment of the present invention.

Since the processing capacity of the control unit 2 in the personal computer system has become extremely high speed, it is now possible to transfer data at high speed without using the DMAC. That is, it can be realized by providing a simple interface 25 from the data bus 9, the address bus 10, and the control line 11, processing the contents of the LBP memo 3 by the control unit 2, and reading the data from the interface 25 at high speed. Further, as the transfer speed control means 6, the FIFO 17 of the previous embodiment is used.
Switching circuit 27, RAM or memory similar to RAM, address decoder 28, LBP data transfer circuit 29 without using
It can also be realized by the configuration of. That is, the switching circuit 27 is RA
When the M26 and the interface 25 are connected, the address decoder 28 is used to store the contents of the LBP memory 3 in the RAM 26. The switching circuit 27 is RAM
In the state where the 26 and the parallel / serial conversion circuit 23 are connected, when the LBP side requests data by the LBP data transfer circuit 29, the address decoder 28 is used to transfer and record the data to the LBP side. Even in the example, there is an effect that recording can be performed at the maximum recording speed of LBP by a small-scale hardware configuration.

Although the LBP is used as the page printer in the present embodiment, the present invention is not limited to this and can be similarly realized by using a page printer such as an LED printer or an LCX printer.

[Effects of the Invention] According to the present invention, since it is not necessary to mount a frame memory for storing a recording image and a character generator on the LBP side, it is possible to reduce the cost of a page printer and to add hardware to a personal computer. Since the number is small, the price of the entire personal computer system can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a recording processing flowchart of the personal computer of FIG. 1, and FIG. 3 is of FIG.
Timing chart of main part in means for matching data read from LBP memory with transfer rate to LBP, 4th
The figure shows a block diagram of another embodiment of the present invention. 1 ... PC, 2 ... control unit, 3 ... LBP memory,
4 ... writing means, 5 ... reading means, 6 ... transfer rate control means, 7 ... LBP, 8 ... CPU, 9 ... data bus, 10 ...
… Address bus, 11 …… Control line, 12 …… Main memory,
13 …… Character generator, 14 …… CRT controller, 15 …… DMAC, 16 …… Buffer, 17 …… FIFO memory,
18 ... Oscillation circuit, 19 ... Counter, 20 ... RS flip-flop, 21 ... AND circuit, 22 ... Counter, 23 ... Parallel / serial conversion circuit, 24 ... Buffer, 25 ... Interface circuit, 26 ...... RAM memory, 27 …… Switching circuit, 2
8 …… Address decoder.

Claims (5)

[Claims] 1. A print control system for a personal computer system in which a page printer is connected as a printing device. The print frame is connected to an internal bus of the personal computer system and stores print information of at least one page of the page printer as an image. A memory and a print image writing unit connected to the internal bus to develop print information as an image and write the image data to the print frame memory via the internal bus; A print image reading means for reading image data from the frame memory for printing at a speed higher than the printing speed of the printer through the internal bus, and a page printer which is provided inside the personal computer system and which reads the image data. Printing speed A print control system for a personal computer, comprising: a transfer speed control means for matching and outputting. 2. The transfer speed control means has a line buffer for at least one line, and outputs the image data for each line from the line buffer in synchronization with a horizontal synchronizing signal from the page printer. Claims No. 1
A print control system for a personal computer according to the item. 3. The print control system for a personal computer according to claim 1, wherein said writing means develops an image of a character created by using a character generator in said personal computer in said frame memory for printing. 4. The print control system for a personal computer according to claim 1, wherein the writing means writes a graphic image created by a CRT controller in the personal computer in the print frame memory. 5. The print control system for a personal computer according to claim 1, wherein a frame buffer in the personal computer is shared as the print frame memory.