JPH09169142A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a drawing time by providing function dividing a frame buffer, function forming intermediate data to the divided frame buffer and function dividing the divided frame buffer into a video developing part and a drawing part. SOLUTION: A printer controller is equipped with a CPU (central operational processor) 1, an ROM 2, an RAM 3, a communication.video control part (engine control part) 4, a printer engine part 5, a data bus 6, a serial I/F 7 and a video I/F 8. The CPU 1 has an imaginary unit to control this region and the ROM 2 has a program or a font. The RAM 3 has a region called a frame buffer having a data region or printing data as an image. The communication.video control part 4 controls a printer engine part 5 by the serial I/F 7 and the image of the frame buffer of the RAM 3 is transmitted to the printer engine part 5 by the video I/F 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a word processor, and various other printing devices having a printing function, and more particularly to a TLB (Translatio) of a CPU.
The present invention relates to a method for compressing / decompressing image data by using the n Lookside Buffer function.

[0002]

2. Description of the Related Art A method of compressing data in a virtual storage area and swapping it out to a hard disk in a file server or a workstation is known. A method of compressing / expanding image data using the TLB function in a printing apparatus has also been proposed. By this method, it is possible to efficiently deal with compression / expansion of data arranged in the main scanning direction and swap-in / out of data. Is now possible.

[0003]

However, the above-mentioned conventional method is mainly used for data swap-in / out in the case of data arranged in the sub-scanning direction such as a line perpendicular to the main scanning direction (see FIG. 4). It took a lot of time and had to be inefficient.

According to the present invention, a method of compressing / decompressing image data by using the TLB function is combined with a partial bit map technique for dividing a memory for a memory saving measure, thereby shortening a time required for drawing. An object of the present invention is to provide a printing device that can perform printing.

[0005]

In order to achieve the above object, the present invention provides a CPU having a function of a virtual memory unit.
In a printing apparatus having a controller unit equipped with a function of setting a frame buffer in a virtual storage unit, a function of securing a real memory as a swap area of the frame buffer, a function of detecting a mishit at the time of drawing access of the frame buffer, It has a function of compressing and storing image data in the swap area according to the detection result, a function of extracting data from the swap area while decompressing it, a function of dividing the frame buffer, and an intermediate code for the divided frame buffer. It has a function of dividing the divided frame buffer into a video data expansion unit and a drawing unit.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a printer controller of a printing apparatus of the present invention. This controller includes a CPU (Central Processing Unit) 1, RO
An M2, a RAM 3, a communication / video control unit (engine control unit) 4, a printer engine unit 5, a data bus 6, a serial I / F 7, and a video I / F 8 are provided. CPU1
Has a virtual memory unit (TLB) and manages this area. The ROM 2 has programs and fonts. R
The AM3 has a data area and an area called a frame buffer having print data as an image. The communication / video control unit 4 controls the printer engine unit 5 by the serial I / F 7, and transfers the image of the frame buffer in the RAM 3 to the printer engine unit 5 by the video I / F 8.

FIG. 2 is a chart showing a list of tasks of the printer controller. (1) is an engine control task dedicated to the interface with the printer engine unit 5. (2) is a print control task that controls printing such as paper feed, video start, and designation of a paper feed tray for the engine control task. (3) is a compression / expansion task for compressing / expanding the (virtual) frame buffer.
(4) is a drawing task that specializes in drawing in the frame buffer. In some cases, the printer emulation task (5) may directly draw in the frame buffer. The printer emulation task (5) instructs the drawing task (4) to draw the data received from the host in the frame buffer.

FIG. 3 is an explanatory diagram showing an example of printing using the TLB function. The CPU 1 has a 4 Gbyte virtual space 11, and the frame buffer is mapped to this virtual space 11. The drawing control unit (drawing task) of the printer draws a character image at a specified location (frame memory space) in the virtual space 11. At this time, the access to the virtual space 11 causes the CPU 1 to generate an interrupt, and the image compression / expansion control unit (compression / expansion task) is notified by the CPU 1 that the drawing task has performed drawing. .

The TLB block 11a of 4 k bytes is set within a range in which the lower (4k-1) bytes of the address of the address access that caused the interrupt are masked. By this operation, an interrupt will not occur even if an access occurs in the 4 kbyte virtual space of the TLB block 11a. In this way, memory management is performed with the space of 4 kbytes as one unit, and during this period, drawing is performed by combining the memory compression and expansion functions. As can be seen from FIG. 3, this memory-saving printing technique can be developed relatively advantageously when there are many continuous drawing in the main scanning direction, but when there are many drawing in the sub-scanning direction as shown in FIG. Swap-in / out processing overlaps, which is a disadvantage. Therefore, as shown in FIG. 5, an intermediate code is generated by dividing it for each bitmap in advance, and the divided area is further divided into a drawing area and a scan area by a toggle (section 0, section 1). When the partial bitmap method of drawing from the intermediate code of 3 is combined, the drawing data is relatively easily accommodated in the main scanning direction internally, so that the data swap-in / out hardly occurs.

[0010]

As described above, according to the present invention,
By combining the compression / expansion method by TLB and the technique of partial bitmap, it is possible to provide a printing device capable of high-speed printing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a printer controller of a printing apparatus of the present invention.

FIG. 2 is a chart showing a list of tasks of a printer controller.

FIG. 3 is an explanatory diagram showing a printing example using a TLB function.

FIG. 4 is a diagram showing an image having many vertical lines, which is not suitable for a printing method having a TLB function.

FIG. 5 is an explanatory diagram showing mapping of a partial bit map type frame buffer.

[Explanation of symbols]

 1 CPU 2 ROM 3 RAM 4 Communication / Video Control Unit 5 Printer Engine Unit 6 Data Bus 7 Serial I / F 8 Video I / F

Claims (1)

[Claims] 1. A CPU having a function of a virtual memory unit
In a printing apparatus having a controller unit equipped with a function of setting a frame buffer in a virtual storage unit, a function of securing a real memory as a swap area of the frame buffer, a function of detecting a mishit at the time of drawing access of the frame buffer, It has a function of compressing and storing image data in the swap area according to the detection result, a function of extracting data from the swap area while decompressing it, a function of dividing the frame buffer, and an intermediate code for the divided frame buffer. A printing apparatus having a function and a function of further dividing a divided frame buffer into a video data developing unit and a drawing unit.