JPH09247403A - Digital image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilizing the whole area of a large capacitance of non- volatile memory without deteriorating data transfer speed by executing control for selecting the area in the non-volatile memory where storage is executed in accordance with the compression rate of image data. SOLUTION: Printing data transmitted from a host 1 is received through an interface 2 and transferred to a printing data extending part 3. Printing data transferred to the printing data expanding part 3 is expanded to be image data in the printing data expanding part 3 and transferred to an image memory 4. Image data transferred to the image memory 4 is data-compressed by an image compressing/expanding part 5 and it is decided in which one of the areas of a hard disk 6 image data is stored by the compression rate of image data so as to store data in the hard disk 6 through a disk controller 7. Thus, image data with the low compression rate is restored in the area with high data transfer speed and the one with the high compression rate is in the low data transfer speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image forming apparatus such as a printer or a digital copying machine, and more particularly to a print controller thereof.

[0002]

2. Description of the Related Art A digital image forming apparatus sometimes uses a hard disk as a recording medium for recording image data. Since the hard disk records data on a recording medium (disk) that rotates at a constant speed, the number of sectors on one track changes. For this reason, the data transfer rate of the hard disk becomes slower as the accessed track approaches the inner circumference of the disk. On the other hand, the digital image forming apparatus must transfer the image data at a constant speed at a speed determined by the drawing means.

[0003]

For this reason, when it is desired to utilize the entire hard disk, the data transfer rate of the digital image forming apparatus must be determined according to the portion of the inner peripheral side of the hard disk where the data transfer rate becomes slow. The data transfer rate of the digital image forming apparatus becomes slow.

Therefore, an object of the present invention is to provide a digital image forming apparatus capable of effectively utilizing the entire area of a large-capacity nonvolatile memory represented by a hard disk without lowering the data transfer rate. .

[0005]

To achieve this object, the first invention stores a plurality of pages of image data,
A large-capacity non-volatile memory that is rewritable and does not have a constant data transfer rate, a data compression unit that compresses image data, a data decompression unit that decompresses the compressed data into image data, and a drawing unit. In a digital image forming apparatus that stores data in a non-volatile memory via a data compression means, transfers the stored image data to a drawing means via a data expansion means, and draws the non-volatile memory into a plurality of areas. The control is performed to select an area in the non-volatile memory to be stored according to the compression rate of the image data.

The second invention is based on the first invention.
It has a receiving means for receiving print data transmitted from a host computer, an image expanding means for expanding the print data into image data, and an analyzing means for analyzing the content of the print data, and analyzes when the print data is received. It is characterized in that the type of image data is discriminated by using a means, and control is performed to select an area in the non-volatile memory to store according to the type of image data.

The third invention is the same as the first invention,
It has a data amount measuring means, measures the data amount of each of the input side and the output side of the data compression means, compares the respective data amounts from the measurement results, and determines the area in the non-volatile memory to store according to the ratio. It is characterized in that selection control is performed.

A fourth invention is the same as the first invention,
It has a data amount measuring means and a time measuring means, measures the data amount of each of the input side and the output side of the data compressing means within a fixed time, and compares each data amount from the measurement result,
It is characterized in that control is performed to select an area in the non-volatile memory to be stored according to the one of the ratios having the smallest compression ratio.

In a fifth aspect based on the third or fourth aspect, the data compressing means and the data decompressing means are capable of performing compression / expansion in block units, and the non-volatile data is stored in block units. It is characterized in that control for selecting a memory area is performed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a printer device according to an embodiment of the present invention. The printer device of the present invention temporarily stores the image data, and a host interface 2 that receives the print data from the host 1, a print data expansion unit 3 that expands the print data received by the host interface 2 into image data. Image memory 4 for image compression / expansion of image data
A decompression unit 5, a hard disk 6 for storing compressed data, a disk controller (SCSI controller) 7 for controlling data input / output to / from the hard disk 6, a CPU 8 for controlling these processes, and C
A program memory 9 in which a control program and the like for the PU 8 and control data and the like are stored, and a printing mechanism unit 10 that performs a printing operation are provided.

FIG. 2 shows the data transfer rate and area separation of the hard disk used in the present invention. In the hard disk 6, since the disk rotates at a constant speed, the rotation time for one rotation is the same for all tracks, but since the number of sectors on one track is not constant, the transfer speed is constant when sequential access is performed. Disappear. This transition of the transfer rate is shown by the curve 11 in FIG.

The hard disk is divided at sector positions A and B, and each area is divided into a low compression image area (0 to A).
Space), a medium compression image area (between A and B), and a high compression image area (between B and C). From FIG. 2, the data transfer rate of the low compression image area is D or more, the data transfer rate of the medium compression image area is E or more, and the data transfer rate of the high compression image area is F or more.

The operation of the printer device of FIG. 1 is as follows. The print data transmitted from the host 1 is received via the host interface 2 and transferred to the print data expanding section 3. The print data transferred to the print data expansion unit 3 is expanded into image data by the print data expansion unit 3 and transferred to the image memory 4. The image data transferred to the image memory 4 is data-compressed by the image compression / decompression unit 5, and it is determined which one of the areas shown in FIG. It is stored in the hard disk 6 via the.

The method of determining the area to be stored is F when the transfer rate transferred to the printing mechanism unit 10 is s and the compression rate of the image data (data amount after compression / data amount before compression) is p / P> s high compression image area E / p>s> F / p medium compression image area D / p>s> E / p low compression image area The compressed data stored in the hard disk 6 is read out via the disk controller 7, decompressed by the image compression / expansion unit 5, transferred to the printing mechanism unit 10, and the print data is graphically drawn.

As described above, the image data having a low compression rate is stored in the high-speed area of the non-volatile memory,
By storing the image data having a high compression rate in the area of the nonvolatile memory having a low data transfer rate, the set value of the print speed of the digital image forming apparatus can be set to a high speed.

Next, an embodiment corresponding to the invention of claim 2 will be described. In this embodiment, the printer device of FIG. 1 is provided with a print data discriminating function, and the print data transmitted from the host 1 is an image image such as a photograph, a graphic image, or a text image. If it is an image image, it is determined in the low compression image area,
If it is a graphic image, it is stored in the medium compression image area, and if it is a text image, it is stored in the high compression image area.

Next, an embodiment corresponding to the invention of claim 3 will be described. In this embodiment, the printer device of FIG. 1 is provided with a function of measuring the input data amount and the output data amount of the image compression / expansion unit 5, and the image compression / expansion is performed when the image data is compressed. The input data amount and the output data amount of the unit 5 are measured and compared.
The ratio (output data amount / input data amount) at this time is set to p, and the storage area is determined and stored in the same manner as above.

Next, an embodiment corresponding to the invention of claim 4 will be described. In this embodiment, the printer apparatus of FIG. 1 is provided with a function for measuring the input data amount and the output data amount of the image compression / expansion unit 5 and a mechanism for measuring the time to compress the image data. At this time, the amount of data input and the amount of output data of the image compression / decompression unit 5 within a fixed time are measured and compared. This ratio is stored, the ratio of each time period is compared, and the one with the highest ratio is set to p, and the storage area is determined and stored in the same manner as above.

Next, an embodiment corresponding to the invention of claim 5 will be described. In this embodiment, the compression method of the image compression / expansion unit 5 is a compression method that performs compression in block units. As a result, one compressed data is created for one image block. Therefore, the data amount is compared in image block units as in the embodiments corresponding to claims 3 and 4, and each image block unit is compared. Determine the storage area.

[0020]

According to the first aspect of the invention, the large capacity nonvolatile memory is divided into areas according to the data transfer rate, and the area to be stored is selected according to the compression rate of the image data. The speed of transfer to the drawing means can be set to a high speed. Further, since the compressed image data is stored in a large-capacity nonvolatile memory such as a hard disk, it is possible to store a plurality of pieces of image data, and continuous printing and electronic sorting are possible.

According to the second aspect of the present invention, since the type of data is discriminated from the print data to determine the storage area, the time for the discrimination is omitted and the processing speed is increased. Further, since a buffer for discrimination is not required, the cost can be reduced.

According to the third aspect of the present invention, since the compression rate can be accurately obtained by measuring and comparing the data amounts on the input side and the output side of the data compression means, the entire nonvolatile memory can be obtained. It can be used more effectively.

According to the fourth aspect of the present invention, since the fluctuation of the compression rate can be obtained by obtaining the compression rate within a fixed time, the compression rate is stored according to the worst compression rate of the image data. As a result, the entire nonvolatile memory can be used more effectively. Further, since the compression rate is stored at the worst value, the image memory can be made small.

According to the invention of claim 5, since the compression rate for each block is calculated and stored, each block can be stored in an optimum area and the non-volatile memory can be effectively used. . Further, since the data is discriminated and stored for each block, the buffer for the discrimination can be made small.

[Brief description of drawings]

FIG. 1 is a block diagram of a printer device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the data transfer rate and area distribution of the hard disk used in the present invention.

[Explanation of symbols]

 5 Image compression / decompression unit 6 Hard disk 10 Printing mechanism unit

Claims (5)

[Claims] 1. A large-capacity non-volatile memory that stores image data of a plurality of pages and is rewritable and has a constant data transfer rate, a data compression unit that compresses the image data, and the compressed data into image data. A digital image which has a data decompression means for decompressing and a drawing means, stores image data in a non-volatile memory through the data compression means, and transfers the stored image data to the drawing means through the data decompression means for drawing. In the forming apparatus, the non-volatile memory is divided into a plurality of areas, and control is performed to select an area in the non-volatile memory to be stored according to a compression rate of image data. 2. A receiving means for receiving print data transmitted from a host computer, an image expanding means for expanding the print data into image data, and an analyzing means for analyzing the content of the print data according to claim 1. When the print data is received, the type of image data is discriminated by using the analysis means, and control is performed to select an area in the non-volatile memory to be stored according to the type of image data. Digital image forming apparatus. 3. The data amount measuring means according to claim 1, wherein the data amount of each of the input side and the output side of the data compressing means is measured, the respective data amounts are compared from the measurement result, and the ratio is calculated. A digital image forming apparatus, characterized in that control is performed to select an area in a non-volatile memory to be stored accordingly. 4. The data amount measuring means and the time measuring means according to claim 1, wherein the data amount of each of the input side and the output side of the data compressing means is measured within a fixed time, and each of them is measured based on the measurement result. A digital image forming apparatus characterized in that control is performed to compare data amounts and select an area in a non-volatile memory to be stored according to the one of the ratios having the smallest compression rate. 5. The data compression means and the data decompression means according to claim 3, wherein the data compression means and the data decompression means can perform compression / expansion in block units, and select an area of the non-volatile memory to be stored in each block unit. A digital image forming apparatus characterized by being controlled.