JPH04173159A - Video data control circuit - Google Patents

Abstract

PURPOSE:To make possible the printing of an image rotated at 180 deg. by providing an address decrement device of a page buffer and an LSBAMSB bit exchange device of data. CONSTITUTION:When an image is normally printed, an address 'OH' and an increment are set in an address counter 2, and data is read in the order of ABC... from a page buffer 1 by setting bit replacement OFF. Subsequently, a drawn image is printed as such. When set in the 180 deg. page rotate mode, an address 'XH' and a decrement are set in the address counter 2, and data is read in the order of ZYX... by switching a bit replacement part ON. Thus an image rotated at 180 deg. based on an image drawn in a page buffer 1 is printed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video data control circuit, and particularly to a video data control circuit used in a page printer having high print quality.

[Conventional technology]

Conventionally, this type of video data control circuit has not had a 180 degree page rotation function.

[Problem to be solved by the invention]

The above-mentioned conventional page printers only have a 90 degree page rotation function, so they have the disadvantage of not being able to print on both sides.

[Means to solve the problem]

The video data control circuit of the present invention includes a page buffer for one page, an address counter that controls setting of the address of the page buffer and increment/decrement of the address, and LSB of data read from the page buffer. It is configured to include a bit exchange section that exchanges bits of ←→MSB, a parallel/serial conversion section that converts the read data into serial data, and a video control section that controls each of them.

〔Example〕

Next, the present invention will be explained with reference to the drawings. Figure 1 is a block diagram of the present invention, Figure 2 is a diagram of page buffer address allocation, and Figure 3 is normal printing (portrait).
FIG. 4 is a diagram showing the printing results when the page is rotated 180 degrees.

First, in the case of normal printing, the address “
Set the count up as ``OH'' and turn off the bit exchange.
By doing so, reading from page buffer 1 is “
The drawn image is printed in the order of A B C...'°, and the printed image is as shown in FIG. 3.

In case of 180 degree page rotation, address counter 2
By setting the address "XH"' and countdown to , and turning on the bit exchange section, reading from page buffer 1 will be in the order of 'zyx...'', and the image drawn on page buffer 1 will be rotated 180 degrees. The resulting image is printed, and the print result is as shown in FIG.

〔Effect of the invention〕

As explained above, the present invention has an address decrement I/means for a page buffer and a data LSB←MSB bit exchange means, so that 180 degree page rotation printing can be performed, so that screen printing is possible. There is.

[Brief explanation of drawings]

Figure 1 is a block diagram of the present invention, Figure 2 is a diagram showing the page buffer address allocation, Figure 3 is a diagram showing the printing results for normal printing (portrait), and Figure 4 is a 180 degree page. FIG. 7 is a diagram illustrating printing results of rotation. 1...Page buffer, 2...Address counter,
3...LSB HMSB bit exchange section, 4...Parallel/serial conversion section, 5...Video control section.

Claims (1)

[Claims] A page buffer for one page, an address counter that controls setting of the address of the page buffer and increment/decrement of the address, and a bit exchange unit that exchanges bits of LSB←→MSB of data read from the page buffer. , a parallel/serial conversion unit that converts the read data into serial data, and a video control unit that controls each of the parallel/serial conversion units.