JPH04291572A - Page memory management equipment for video page printer - Google Patents

Abstract

PURPOSE:To attain read/write of an image data of a succeeding page during print by using a page memory with a capacity of one page of a video printer. CONSTITUTION:An image data stored in a page memory 1 able to store only the image data of bit image by one page of a video printer 5 is read by an address generated from an address counter 2 and outputted to the video printer 5. On the other hand, an image data stored in a file device 7 is once stored in a buffer memory 6 and written in the page memory 1 by an address generated from a write address counter 3. A comparator 4 outputs a count enable signal to the write address counter 3 only when a content of the write address counter 3 is smaller than the content of the printer read address counter 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a page memory management device for a video page printer, and more particularly to a page memory management device for a video page printer that can realize continuous high-speed printing of image data using only one page's worth of page memory.

0002

[Prior Art] Conventionally, in this type of video page printer, a page memory for two pages is prepared for continuous high-speed printing of image data, and while the image data is being output to the printer, another page is stored in the page memory. The image data for the next page was read from a file device such as a fixed magnetic disk, using so-called double buffer control.

0003

The above-mentioned conventional method has the disadvantage that as the resolution increases, the amount of memory required for the page memory increases, making it difficult to achieve a low price.

SUMMARY OF THE INVENTION An object of the present invention is to provide a page memory management device for a video page printer that eliminates the above-mentioned drawbacks and significantly reduces the page memory capacity.

[0005]

[Means for Solving the Problems] The device of the present invention is a page memory management device for a video page printer that manages a page memory that holds image data of bit images for one page of the video page printer. a printer read address counter that holds an address for reading image data into the video page printer; a write address counter that holds an address for writing image data read from a file device using the DMA method into the page memory; and a value of the printer read address counter. and a comparator that compares the value of the write address counter with the value of the write address counter and outputs a count permission signal to the write address counter only when the value of the write address counter is smaller than the value of the printer read address counter. .

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

The embodiment shown in FIG. 1 includes a page memory 1 for storing one page of image data, and a page memory 1
a printer read address counter 2 that generates a read address; a video printer 5 that records read data of the page memory 1; a file device 7 that stores image data; In Fire
a buffer memory 6 for storing data using the st Out) method;
The write address counter 3, which generates the write address for writing the data read from the buffer memory 6 into the page memory 1, compares the values of the printer read address counter 2 and the write address counter 3, and determines that the count value of the write address counter 3 is small. The comparator 4 outputs a count permission signal to the write address counter 3 only when the data is read, and the inverter 8 forms a page memory write clock signal shifted by half a cycle from the page memory read clock signal. The bus and address bus are shown together.

Next, the operation of this embodiment will be explained.

The page memory 1 has a function of storing one page of image data. The image data stored in the page memory 1 is sequentially read out at the rising timing of the page memory read clock signal according to the address generated by the printer read address counter 2 and output to the video printer 5.

On the other hand, the image data read from the file device 7 is temporarily stored in the FIFO type buffer memory 6, and is read at the write address at the timing of the page memory write clock signal whose phase is shifted by half a cycle from the page memory read clock signal. The address generated by the counter 3 is read from the buffer memory 6 and written to the page memory 1.

The value of the write address counter 3 and the value of the printer read address counter 2 are constantly input to the comparator 4, and only when the value of the write address counter 3 is smaller than the value of the printer read address counter 2, the value of the write address counter 3 is inputted to the comparator 4. By outputting a count enable signal, which is a count enable signal, the image data of the next page being read from the file device 7 and written to the page memory 1 will destroy the image data currently being read from the page memory 1 and being output to the printer. It prevents

[0013]

Effects of the Invention As explained above, the present invention compares the value of the printer read address counter and the value of the write address counter of the page memory during printing, and fills in unnecessary portions that have already been output to the printer. By writing the image data of the next page read from the device, the next image data can be written to the file device during printing using a page memory with a capacity of one page instead of having a page memory with a capacity of two pages. This has the effect of being able to read from and write to page memory.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

[Explanation of symbols]

1 Page memory 2 Printer read address counter 3
Charge address counter 4 Comparator 5 Video printer 6 Buffer memory 7 File device 8 Inverter

Claims (1)

[Claims] 1. A page memory management device for a video page printer that manages a page memory that holds image data of a bit image for one page of a video page printer, wherein an address for reading image data from the page memory to the video page printer is specified. Printer read address counter held and D from file device
A write address counter that holds the address for writing the image data read in the MA method into the page memory is compared with the value of the printer read address counter and the value of the write address counter, and the write address is determined from the value of the printer read address counter. A page memory management device for a video page printer, comprising: a comparator that outputs a count permission signal to the write address counter only when the value of the counter is small.