JPH0230557A - Printer - Google Patents

Abstract

PURPOSE:To obtain a printer of VBB system with a reduced frequency of occurrence of over run error by disposing a text memory part and a VBB part in the same memory space and varying the capacity of the VBB part within this space. CONSTITUTION:A text memory part 8 and a video band buffer(VBB) part 9 are continuously disposed in the same memory space. A VBB area control part 13 increasing/decreasing the capacity of the VBB part 9 with the instruction from a CPU 3, and a barrel shifter part 7 writing a font to the VBB part 9 while shifting the font are provided. Only when an address specified by the VBB area control part 13 in the VBB part 9 is accessed, data passes through the barrel shifter part 7. when an address in the text memory part 8 is accessed, data detours around the barrel shifter part 7 to be written.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printing device used as an output device of a burner computer or the like.

BACKGROUND OF THE INVENTION In recent years, printing devices have been required to be faster and more functional. In particular, electrophotographic printing units that use laser diodes, LED arrays, etc. as light sources are rapidly expanding in use due to their high speed and high printing quality. Naturally, a high-speed printing device such as the above-mentioned printing device is required to have high printing data processing ability.

There are various types of these print data processing methods, but they can be roughly classified into two types of processing methods.

Hereinafter, conventional examples of two types of processing methods will be explained with reference to the drawings. FIG. 2 is a block diagram of a conventional printing device of page memory type. The printing device 1 is divided into a controller section 1a that processes print data sent from a host computer 2, and a printing section 1b that prints on paper. The controller unit 1a includes a CPU 3 that controls data processing, a program ROM 4 that stores a program for operating the CPU 5, a font ROM 5 that stores font data corresponding to character codes, and an interface unit that receives print data from the host computer 2. 6. Page memory section 14 that stores image data for one page, barrel/lid section 7 that writes fonts to the page memory section 14 while moving 7 feet, and page memory section 1
4, and converts it into serial data and outputs it to the printing section 1b. The printing section 1b includes a printing mechanism section 12 that performs printing, and a printing mechanism control section 11 that controls the printing mechanism section 12.

The operation of the conventional page memory type printing apparatus configured as described above will be explained with reference to the processing procedure diagram of FIG. In FIG. 4, the printing device 1 receives a character code from the host computer 2. In FIG. The character code 61H represents the lowercase letter "a" of the alphabet, and a character code is determined for each character in a one-to-one correspondence. CPU3 resolves this character code and font R
The corresponding font data is read from the OM5 and written into the page memory section 14. During this writing, the font data is read from the font ROM 5 in bytes or words, but in order to place the font in an arbitrary bit position in the page memory section 14, the font data is read out through the barrel/lid 7. The data is stored in the page memory unit 14. In this way, the image to be printed in the page memory section 14! , -1, data is created for one page (
Figure 4 ■). When the image creation for one page is completed, the controller section 1a activates the printing section 1b and starts outputting print data. The print data is converted from parallel data to serial data for each raster by the parallel-to-real converter 1o, and is output to the print mechanism controller 11 to obtain the print result shown in FIG. 4 (2).

As described above, the conventional printing apparatus of the page memory type has the advantage of being able to store the exact image data of one printed page, but has the disadvantage of requiring a very large amount of memory. For example, when printing on letter paper (8.5 inches x 11 inches) at a resolution of 300 dots/inch, approximately 1 MB (1 megabyte) of memory capacity is required. In order to eliminate the above drawbacks, 1/n
2. Description of the Related Art There is a printing device using a video pandolphusa type (hereinafter referred to as a VBB type) that prints using an image development area of a page.

A conventional example of the VBB method will be described below with reference to the drawings.

FIG. 3 is a block diagram of a conventional printing device using the VBB method. The printing device 1 includes a controller section 1a' that processes print data sent from the host computer 2.
and a printing section 1b that prints on paper. The printing section 1b has the same configuration as the printing section of the page memory type printing device. The controller unit 1a' includes a CPU 3 that controls data processing, a program ROM 4 that stores a program for operating the CPU 3, and a font ROM 5 that stores font data corresponding to character codes.
, an interface unit 6 that receives print data from the host computer 2, a text memory unit 8 that stores character codes for one page in the form of text, and a VBB unit 9 that stores image data for one page 1/n. , Barrel shifter 7 that writes to VBB section 9 while shifting the font, VBB
Parallel units 6, - read out the image data stored in section 9, convert it into serial data, and output it to printing section 1b.

It consists of a serial converter 10.

The operation of the conventional printing apparatus of the VBB type constructed as described above will be explained according to the processing procedure diagram shown in FIG. In Fig. 4 ■, the printing device 1 is the host computer 2.
Receive character code from.

The CPU 3 interprets this character code and creates a text in the text memory section 8 by adding the character code and information such as the writing position of the character in the VBB section 9. In this way, a text group corresponding to the character codes for one page is created in the text memory section 8 (FIG. 4@). After creating one page of text, the CPU 3 writes the font to the VBB section 9 while interpreting the text from the beginning. Since the VBB section 9 has a memory capacity of only 1/n page, the CPU 3 can initially only interpret text for 1/n page. When the images for 1/n pages are completed, the CPU 3 activates the printing section 1b to start printing (FIG. 4 - ). At the same time, print data from the VBB unit 9 is outputted to the parallel-to-serial conversion unit 1o for each raster, converted into serial data, and outputted to the printing mechanism control unit 11.

By outputting each raster, an empty area is generated in the VBB section 9. The CPU 3 writes the next line's font to the VBB section 9 every time an empty area occurs.

By alternately repeating the output from the VBB section 9 and the writing to the VBB section 9 in this way, it is possible to print one page ((2) in FIG. 4). For this reason, the VBB section 9 usually has a ring buffer structure and has a capacity of 1/n of one page, but can be used infinitely in terms of virtual address space.

As described above, the conventional printing device using the VBB method can perform printing with 1/n of the VBB and a small amount of text memory compared to the printing device using the page memory method, so it has the advantage of being able to significantly reduce the memory capacity.

Problems to be Solved by the Invention However, when the density of character data becomes high in the printing device of the VBB method, the writing time of the CPU 3 to the VBB section 9 becomes longer. This has the disadvantage that an overrun error occurs in which the printer is overtaken and becomes unable to print.

The present invention has been made in view of these points, and an object of the present invention is to provide a printing device that uses the VBB method and has a low frequency of occurrence of overrun errors.

Means for Solving the Problems The present invention includes a VBB area control section that arranges the text memory section and the VBB section in the same memory space and changes the capacity of the VBB section within the space.

The VBB area control unit changes depending on whether the printing density is high or low.
By increasing/decreasing the BB area, overrun errors can be prevented and limited memory capacity can be used effectively.

Embodiment FIG. 1 is a block diagram showing an embodiment of the printing apparatus of the present invention. In the figure, 8 is the text memory section, 9 is the VB
This is part B, and the text memory part 8 and the VBB part 9 are arranged consecutively in the same memory space. 13 is a VBB area control unit that increases or decreases the capacity of the VBB unit 9 according to instructions from the CPU 3; 7 is a barrel shifter unit that writes the font while shifting it to the VBB unit 9;
A structure in which data is written through the barrel shifter section 7 only when accessing an address in the VBB section 9 specified by , and data bypasses the barrel shifter section 7 when accessing an address in the text memory section 8. It becomes. The other parts have the same configuration as the conventional VBB type printing device.

In the printing device of the present invention configured as described above, the fifth
The operation when the user arbitrarily changes the VBB amount from the operation panel of the printing device will be described according to the flowchart shown in the figure. When the user desires to change the VBB capacity, such as when printing a page with high print density (Step 2), the desired VBB capacity is input and set from the operation panel by key operation (Step @). Note that when the printing density is high, input is made on the operation panel to increase the VBB capacity. In addition, if there is no change in VBB capacity, the current V
The BB capacity remains the same. The CPU 3oA-7 instructs the VBB engineering IJ controller 13 about the set VBB capacity (step O). VBB area control section 1
Step 3 secures the designated VBB capacity and allocates addresses to the remaining area as the text memory section 8 (step @). The interface section 6 receives the print data (character code, etc.) sent from the host computer 2 (step @), and the CPU 3 creates the text of the received data in the text memory section 8 (step O). Repeat steps ■ to ■ until one page of text has been created (step ■). When the text creation for one page is completed, the CPU 3 changes the font R while interpreting the text.
The font image is read from the OM 5 and expanded to the VBB section 9 through the barrel shifter section 7 (step 2). Step until the currently set VBB capacity is full ■
Repeat ~■.

When the VBB section 9 becomes full, the CPU 3 instructs the printing mechanism control section 11 to start printing (step 2). The instructed printing mechanism control section 11 controls the printing mechanism section 12 to start printing (Step 2). When printing is started, the image developed in the VBB section 9 is outputted to the printing mechanism control section 11 via the parallel-to-real conversion section 10 for each raster, and the output portion becomes an empty area within the VBB. . In this way, the CPU 3 waits for expansion until the empty area in VBB becomes large enough to expand the next line of text (
Step ■). When the next line of text becomes ready to be developed, the CPU 3 again interprets the text and develops the font image in the VBB section 9 (step O). Steps 1 to 2 are repeated until the text expansion of the last line is completed (steps). When text development is completed, printing ends after all images in VBB are output (step 2).

As described in detail above, the printing device of this embodiment has a configuration in which the VBB capacity can be changed, so that the memory capacity can be reduced compared to the page memory method, and the printer does not have to wait for the completion of one page. Printing is activated only by expanding the VBB capacity, and printing time is also shortened. Furthermore, it is possible to provide a printing device in which overrun errors occur less frequently even with the conventional VBB method, which is extremely useful in practice.

In this embodiment, input from the front panel by the user was explained as a means of changing the VBB capacity, but other means of changing include commands from the host computer or the CPU itself calculating the data density to determine the optimum VBB capacity. Various configurations are possible, such as changing the configuration to
Similar effects can be obtained in either case.

Effects of the Invention The printing device of the present invention arranges the text memory section and the VBB section in the same memory space, and makes it possible to change the capacity occupied by the VBB section within this space. The combined memory capacity of the parts can be made smaller than before, and the VBB area can be increased or decreased depending on the printing density, etc. Accordingly, the occurrence of overrun errors can be suppressed, making it practical. It is excellent.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the printing device of the present invention, FIG. 2 is a block diagram of a conventional page memory type printing device, FIG. 3 is a block diagram of a conventional VBB type printing device, and FIG. 4 is a block diagram of a conventional printing device of the VBB type. FIG. 6 is a flowchart of the operation of the printing apparatus of the present invention. DESCRIPTION OF SYMBOLS 1... Printing device, 1a... Controller section, 1b... Printing section, 2... Host computer, 3... CPU, 4... ...Program ROM, 5 ...Font ROM, e...
・Interface part, 7... Barrel shifter part, 8...
...Text memory section, 9...788 copies, 1o.
...Parallel-serial converter, 11...Printing mechanism control section, 12...Printing mechanism section, 13...V
BB area control unit, 14...page memory unit. Agent's name: Patent attorney Shigetaka Awano and 1 other person] - To Doro, Otsu 2H. 19H, 7AH 61H, b2s- 1'ls, IAs Diagram

Claims (1)

[Claims] a memory comprising a first area for storing data such as an input character code and a second area for storing developed data of an image corresponding to the data such as the character code;
A printing device comprising an area control means for changing the second area occupied in the memory, and a printing means for extracting data from the second area and printing according to the data.