JPS60245362A - Printer control device - Google Patents

Abstract

PURPOSE:To make a storage capacity small by reading the next page data in a storage device by utilizing a recording ineffective time required when a mechanical system of a laser printer resynchronizes. CONSTITUTION:Line end information for showing the line end is contained in an output data read out of a page memory 2, and when this information is detected by a line end detector 28, a DMA (direct memory access) request signal RQ falls. As for a laser printer, a laser beam is deflected by a mechanical scanning means, therefore, a resynchronization is applied by a horizontal synchronizing signal HS at every main scan. Accordingly, a period T0 of the synchronizing signal HS becomes constant. The time T2 when the DMA request signal RQ falls is a time of the printer part cannot execute recording, therefore, by using this time T2, the area of the page memory 2 which ended recording is rewritten by a data of the next page, when a line synchronizing signal LS for showing the end of each line has risen.

Description

TECHNICAL FIELD The present invention relates to a printer control device, and more particularly to a control device for a Radhe printer that forms an image by rask scanning of a Radhe beam.

BACKGROUND OF THE INVENTION In recent years, laser printers have been put into practical use as hard copy devices in converter systems. This laser printer outputs a recorded image (including characters, symbols, etc.) onto recording paper by scanning to generate image data that is expressed by dividing it into dots. Image formation is performed as follows. .

First, an electrostatic latent image of a recorded image is formed on a uniformly charged photoreceptor by raster scanning with a laser beam. After this electrostatic latent image is developed with toner, it is transferred to a sheet of paper, and the image is fixed on the sheet of paper by pressure heating and then discharged.

Since the electrostatic latent image deteriorates if left unused, it is necessary to expose the recorded image for one page onto the photoreceptor in as short a time as possible. Furthermore, the recording density in a laser printer is, for example, about 12 dots/1yn (in both the main scanning direction and the sub-scanning direction).
Because of its high density (300DP■), the amount of data for one page is extremely large. Therefore, it is necessary to transfer recording data at a high data rate of, for example, 3 Mbit/sec.

Such high-speed data transfer is nearly impossible with program transfer using a normal general-purpose microprocessor, so
Conventionally, data transfer to the recording control section of a radar printer has been performed in the following manner.

In other words, two sets of page memories are provided to temporarily store one page's worth of record data, and the record data is transferred from one page memory to the record control unit via DMA (Direct Memo).
The data transfer speed is ensured by adopting a so-called double buffer configuration in which the next page of recorded data from an external device (for example, a host machine such as a computer) is stored in the other page memory.

However, such a conventional device requires two sets of page memories, making the device configuration complicated.

OBJECTS It is an object of the present invention to provide a printer control device that eliminates the drawbacks of the prior art and realizes a simple device configuration.

composition The present invention will be explained below based on one embodiment.

FIG. 1 shows an embodiment of a control system when the present invention is applied to a laser printer device.

In the figure, this device includes an interface 1 to which recorded data RD consisting of character code display information and control codes is added from an external device, and a page memory 2 that stores output data for one unit, for example, one page. A tsukturn memory 3 that stores character patterns corresponding to character codes, and a parallel/serial (parallel/serial) converter that converts the output data of the tsuyaturn memory 3 into serial raster data and outputs it to the printer section 5.
P/S') converter 4.

The CPU 6 converts the character code included in the record data RD into a corresponding character number, turn number, or storage address in the turn memory 3, and also converts the storage address and display information into pages according to the control code included in the record data RD. Store in memory 2. At this time, the end-of-line information is enabled for characters corresponding to the end of each line.

Furthermore, this device includes a program memory 7 consisting of a ROM (read-only memory) that stores programs executed by the CPU 6, and an RA that forms a work area for the CPU 6.
It has a work memory 8 consisting of M (random access memory).

Further, the control circuit 9 is a DMA controller that accesses the page memory 2 based on the pixel synchronization signal ps and the horizontal synchronization signal H3 that are outputted from the printer section 5, and reads the nogturn data from the nogturn memory 3. . During the operation period of the control circuit 9, the CPU 6 cannot access the page memory 2.

The storage state of the output data in the page memory 2 is
As shown in the figure (,), characters are arranged corresponding to the main scanning direction of the printer section 5, and lines are arranged in the sub-scanning direction. For example, output data with diagonal lines is specified by the number of lines and characters from the reference position, such as the mth character of the kth line.

Further, as shown in FIG. 2B, one unit of output data is (n+1)-bit data bn-b consisting of a storage address, various display information such as the presence or absence of an underline, density, and end-of-line information. It is.

Further, one character pattern in the turn memory 3 takes a format as shown in FIG. That is, for example, if the recording density in the printer section 5 is 12 dots/dpi (300 DPI) in the main scanning direction and the sub-scanning direction, and the character size is 2.54 x 4, 27 ystn (/4 squid size), the character pattern is represented by 30 horizontal dots and 50 vertical dots (lines). Note that this horizontal row of dots constitutes raster data, and therefore one character is formed of 50 rasters.

FIG. 4 specifically shows the peripheral circuits of the control circuit 9, the page memory 2, the l-turn memory 3, and the parallel-to-serial converter 4.

The dot counter 21 counts the pixel synchronization signal ps and outputs the counted value to the pattern memory 3 as part of its address. Is the count value a character)? A character synchronization signal C8 is output every time the number of dots on the side of the turn becomes a multiple of 30, and this signal is applied to the clock input terminal CK of the character counter 22.

The line counter 23 counts the horizontal synchronizing signal H8 and outputs the counted value to the pattern memory 3 as part of its address. Every time the count value reaches the number of vertical dots of a letter or turn, that is, a multiple of 50, that is, every time one line of sub-scanning is completed, a row synchronization signal LS is output, and this signal is sent to the clock input terminal CK of the row counter 24. and add to CPU 6.

Input terminal AKtj of address selector 25: data on address bus AB of CPU 6 is added to input terminal B, and count values of character counter 22 and line counter 24 are added to input terminal B.

Flip-flop 26 is enabled by print request signal RP output from CPU 6 and set by horizontal synchronization signal H8.

Additionally, a line end detector 28 detects that line end information is set in the output data output from the page memory 2.
is reset by the output of The DMA request signal RQ output from the flip-flop 26 is applied to the CPU 6 and also to the switching control terminal B/A of the address selector 25 to control the address selector 25.

Furthermore, while disabling the data buffer 27 to which data on the data bus DB of the CPU 6 is added,
It is also added to an AND circuit 29 that gates the output of the parallel-to-serial converter 4.

Now, when the CPU 6 wants to store output data in the page memory 2, it lowers the print request signal RP, thereby causing the address selector 25 to apply to the input terminal A. The data on the address bus AB is added to the page memory 2 as its address, and the data on the data bus DB is added to the page memory 2 via the data buffer 27. As a result, output data sequentially added from the CPU 6 is stored in the page memory 2.

When data for one page is stored in page memory 2,
The CPU 6 raises a print request signal RP. As a result, the frizzo float 7 is synchronized with the horizontal synchronizing signal H3.
026 is set, the DMA request signal RQ rises (see FIGS. 5(,), (c)), and the address selector 25 transfers the count values of the character counter 22 and line counter 24 that are applied to the input terminal B to the page memory 2. Add as address. While this DMA request signal RQ is rising, the CPU 6 cannot access the page memory 2.

The output data read from the storage area of the page memory 2 addressed by the count values of the character counter 22 and the line counter 24 is added to the nogturn memory 3, thereby determining the address of the storage location of the corresponding character turn. A part of is specified. Therefore, among these letters and turns, the dot counter 21 and line counter 2
Data for 30 dots of one main scanning line (raster) specified by the count value of 3 is read out and output to the parallel-to-serial converter 4. This is converted into a serial signal synchronized with the pixel synchronization signal ps, and outputted to the printer section 5 as raster data DR (see FIG. 5(b)) via an AND circuit 29.

As mentioned above, the output data of each line includes line end information at the end of the line, so when the output data at the end of the line is read out from the page memory 2 for each main scanning line, the end of line detector 28
detects this and uses its output to flip the Flip Flotsuno 2
6 is reset. This causes the DMA request signal RQ
falls down.

In a laser printer, main scanning is performed by deflecting a laser beam using a mechanical scanning means such as a polygon mirror or a holographic scanner, and horizontal synchronization is resynchronized for each main scanning. Therefore, the period To of the horizontal synchronization signal H3 is always constant.

Therefore, as shown in FIG. 5, the printer unit 5 cannot perform recording during the time T2 excluding the time Tl during which the DMA request signal RQ is rising in the period 'ro of the horizontal synchronizing signal H8. During this time, the CPU 6 can freely access the page memory 2. In one example, this period T2 occupies about 30% of To.

Therefore, in this embodiment, the row synchronization signal LS (
FIG. 5(d)) is output from the line counter 23,
With the DMA request signal RQ falling, the CPU 6 rewrites the output data of the line for which recording has been completed with data included in the next page. The main scanning bone resynchronization time in the laser printer,
The data is rewritten during this time by taking advantage of the fact that it is statistically rare for a line to contain valid characters up to the right end.

Note that the period To and time T 1 r of the horizontal synchronizing signal H8
For example, T 2 has the following temporal relationship. For example, the maximum number of characters in one line is 80 characters, the period 'ro is 1.2 milliseconds, and the frequency of the pixel synchronization signal ps is 3 MHz.
Then, in the case of the maximum number of characters, 1 hour required to output one raster data, that is, the maximum value of time Tl, is 8
0×30÷(3×10′)=0.8 milliseconds. Therefore, the minimum value of recording invalid time T2 is o, 4 mi')
The time required for the CPU 6 to store one row of data in the page memory 2 is also longer.

Effect As described above, according to the present invention, the DMA request signal is released at the end of outputting each raster data to the printer.
The CPU can access the page memory during the recording invalid time required when the laser printer's mechanical system resynchronizes. As a result, the storage capacity of the page memory is sufficient for one page, and the configuration of the page memory and its peripheral circuits is simplified, thereby reducing costs.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a control system according to an embodiment in which the present invention is applied to a laser printer device, Fig. 2 (a) is a conceptual diagram showing an example of a storage state of a page memory, and Fig. 3 is a conceptual diagram showing an example of the dot configuration of the letter A turn. FIG. 4 shows the control circuit, page memory, pattern memory and FIG. 5 is a block diagram specifically showing the peripheral circuit of the parallel-to-serial converter, and FIG. 5 is a time chart showing the operation of the main parts of the device shown in FIG. 4. 2...Page memory 3...Pattern memory 6...CPU (Central Processing Unit) 21...Dot counter 22...Character counter 23...Line counter 24...Line counter 25...Address counter 26...Flip float 27...End of line detector Fig. 1 Fig. 2 Fig. 3 Fig. 4 Ji

Claims (1)

[Claims] Receiving recorded data to be output to a printer from a host machine,
A storage means capable of storing at least one unit of this as a two-dimensional array, and when an instruction to output recorded data is received from the host machine, the recorded data is read out sequentially from the storage means for each recording line by rask scanning. In a printer control device having pixel signal forming means for converting into serial pixel signals and sequentially outputting the pixel signals to the printer, the recorded data includes, at the end of each line, an indication that there is no valid recorded data after that line. input to the storage means with a line end indication added; and a two-state means that selectively assumes the first state, and the two-state means changes the first state when the detecting means detects a line end display, and outputs and displays recorded data from the host machine. when the two-state means is in the first state, the two-state means stops converting and outputting the pixel signal in the pixel signal forming means; A printer control device characterized in that the printer control device outputs an instruction to the host machine to permit input of recording data to the storage means.