JPH09190307A - Print system, information processor, printer and print method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compress the data on various images in the compression system in accordance with the contents of every image data and to transfer the compressed image data. SOLUTION: A command is sent to a printer to inquire its expansion/ compression system (S1), and all status codes of the expansion system are received (S2). Then a compression system that is enough to acquire the prescribed efficiency, etc., is chosen out of the expansion systems, so that a compression system is decided (S3). A command is sent to the printer 3 to notify the decided compression system (S4). Then the bit map images equivalent to one page are expanded into a RAM (S5) and undergo the compression processing (S6). These processed images are successively sent to the printer. The printer expands the compressed image data and transfers them top a printer engine to perform the print processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing system, an information processing device, a printing device, and a printing method.

[0002]

2. Description of the Related Art In a conventional printing system, one page of image data is stored in a host computer.
The image data is expanded on the AM, the image data is compressed and transmitted to a printing device such as a page printer, and the printing device performs decompression processing to perform printing. That is, when the transfer speed of the image data from the host computer to the printing device is not faster than the printing speed of the printing device, for example, when one page is printed by a page printer or the like, the image is interrupted halfway. Since overrun occurs, image data compression processing is executed by the host computer in order to apparently increase the transfer speed of the image data from the host computer to the printing device, and the compressed image data is transferred to the printing device and then the printing device The desired printing was performed through a predetermined printing process inside.

[0003]

By the way, although many methods have been proposed for compression / decompression processing of image data, when a lossless compression method is adopted, the compression efficiency is affected by the nature of the image. That is, it is desirable to adopt a compression method with good compression efficiency in order to achieve a certain level of compression efficiency with respect to various images, but a compression method with good compression efficiency is generally a logical method during compression processing. There is a drawback that the calculation is complicated and that the compression processing takes a long time. Therefore, when the image data is compressed by adopting a compression method with good compression efficiency, it takes a long time for the compression process in the host computer even when handling simple image data, resulting in a decrease in the efficiency of the printing system. There was a problem to do.

The present invention has been made in view of such problems, and it is possible to compress image data for various images by a compression method according to the content of the image data and transfer the image data. An object is to provide a printing system, an information processing apparatus, a printing apparatus, and a printing method.

[0005]

According to a first aspect of the present invention, there is provided an information processing apparatus for compressing image data, and a printing apparatus connected to the information processing apparatus so as to be capable of bidirectional communication. In the printing system, a plurality of compression methods are selectably provided in the information processing apparatus, and a plurality of decompression methods are provided in the printing apparatus in a selectable manner. Detecting means for detecting the expansion method, and selecting means for selecting a compression method having a compression efficiency of a predetermined value or more and a minimum compression processing time from compression methods corresponding to the expansion method detected by the detection means. And a compression unit that compresses image data based on the compression system selected by the selection unit, wherein the printing apparatus uses all the expansion methods of the plurality of expansion methods as the information processing apparatus. A notification unit for notifying, is characterized by and a decompression means for performing a predetermined decompression processing to compressed image data by the compression means.

According to a second aspect of the present invention, a plurality of compression methods are selectably provided in an information processing apparatus which is connected to a printing apparatus so as to be capable of bidirectional communication and which performs image data compression processing. Along with the detection means for detecting all the expansion methods of the printing apparatus and the compression method corresponding to the expansion method detected by the detection means, the compression efficiency is a predetermined value or more and the compression processing time is the minimum. The selection means for selecting the compression method and the compression means for compressing the image data based on the compression method selected by the selection means.

Further, according to a third aspect of the present invention, in a printing apparatus which is connected to an information processing apparatus so as to be capable of bidirectional communication and to which image data compressed by the information processing apparatus is input, a plurality of decompression methods are provided. It is characterized in that it is provided in the printing device so as to be selectable, and further comprises notifying means for notifying the information processing device of all the expansion methods of the plurality of expansion methods.

According to a fourth aspect of the present invention, in a printing method in which image data compressed by an information processing device is expanded by a printing device and printed, all the expansions that the information processing device has in the printing device are performed. After requesting the printing device to transmit the type of the method, the printing device returns the types of all the decompression methods to the information processing apparatus, and then the information processing apparatus determines the decompression method of the printing apparatus. A compression method having a compression efficiency of a predetermined value or more and a minimum compression processing time is selected from the corresponding compression methods, the image data is compressed by the selected compression method, and the image data is transmitted to the printing device. The printing device is characterized by decompressing the transmitted image data and outputting it.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a printing system according to the present invention. The printing system includes a host computer 1 (information processing device) for processing image data and a predetermined bidirectional communication. A printer 3 connected to the host computer 1 via an interface 2
(Printing device).

The host computer 1 includes a hard disk (HD) 4 in which an operating system (OS), application programs, etc. are stored, and the HD 4
Hard disk controller (HDC) 5 for controlling
, An interface circuit 6 for performing an interface operation with the printing apparatus 2, a ROM 7 and a RAM 8, and a C
A CPU 10 is provided which is connected to each of the above components via a PU bus 9 and controls each of these components and performs a compression process of image data described later.

The RAM 8 has a system area 8a in which the OS is constructed, an application area 8b in which an application program (hereinafter referred to as "application") stored in the HD 4 is loaded, and an application includes sentences and graphics. Has a work area 8c used for editing and a print buffer area 8d for temporarily storing image data for printing.

Further, the printer 3 includes a buffer RAM 11 for temporarily storing image data sent from the host computer 1, a recording medium carrying mechanism, a semiconductor laser unit, a photosensitive drum, a developing section, a fixing section, a cleaning section,
A printer engine 12 having known components related to a series of electrophotographic processes, such as a separation unit, and a buffer RAM 1.
1 and a printer engine 12 and a printer control unit 13 that exchanges information with the host computer 1 and performs image data expansion processing.

In the present embodiment, the buffer RAM 11
Has a storage capacity much smaller than the storage capacity of one page of image data. Therefore, the amount of image data transferred from the host computer 1 via the bidirectional interface 2 per unit time is The print data amount is larger than the print data amount.
That is, the transmission speed of the bidirectional interface 3 depends on the performance of the host computer 1. However, in the present embodiment, the transmission speed of the bidirectional interface 3 is set so that the overrun does not occur during printing.
The print speed is set higher than 2. In the present embodiment, when the transfer speed of the bidirectional interface 2 guarantees 1/2 of the print speed of the printer engine 12, the compression parameter A representing the compression efficiency threshold for performing the printing operation is 1 /. Set to 2.

FIG. 2 is a flowchart of a printing operation procedure executed on the host computer 1 side, and shows a case where an application prints one page.

In step S1, a command for inquiring about the expansion / contraction method held by the printer 3 is transmitted to the printer 3 via an application.

Next, in step S2, the host computer 1 has a decompression type status code of the printer 3, that is, a run length type or JBIG (Joint).
A status code such as Bi-level Image Coding Experts Group) is received from the printer 3. As a result, the application obtains the decompression method information provided in the printer 3.

Next, in step S3, the application estimates the properties of the bitmap image and selects a compression method sufficient to obtain the compression efficiency of the compression parameter A (= 1/2). As a method of estimating the property of an image, for example, the type of image source (character,
(Figure, dither image, etc.) and the composition ratio of each type of source, or compression efficiency can be estimated by compressing a part of the bitmap image. In the present embodiment, the run length method is selected as the compression method because it is the easiest to process.

Next, in step S4, a compression command is sent to the printer 3 to notify the printer 3 of the selected compression method, and in step S5, the application develops the bitmap image for one page in the print buffer area 8d, and the following. In step S6, the compression processing of the bitmap image for one page is executed, then the compressed image data is sequentially transferred to the printer 3 via the interface circuit 6, and the processing on the host computer 1 side is ended.

FIG. 3 is a flowchart showing a printing operation procedure executed on the printer 3 side.

When the command for the expansion / contraction method held by the printer 2 is received from the host computer 1 in step S1 of FIG. 2 (step S11), a status code indicating the expansion method is returned to the host computer 1 (step S12). . Next, in step S13, the command relating to the compression method selected by the host computer 1 is received. Then, in step S14, the compressed image data sent from the host computer 1 side is decompressed by the printer controller 13 and stored in the buffer RAM 11. To do. Next, the printer control unit 13 sequentially reads the image data in the order of storage and transfers the image data to the printer engine 12 in synchronization with the printing operation of the printer engine 12 (step S15). Based on this, a print image is formed on the recording paper (step S16), and the process ends. The processes of steps S5 to S7 and steps S14 to S16 of FIG. 2 are simultaneously processed in a pipeline manner.

[0022]

As described above in detail, according to the present invention, the optimum compressed image system can be adopted for various images, and therefore the compression system according to the transfer rate of the image data of the information processing apparatus. Can be adopted, and it is possible to avoid a decrease in system efficiency for various images.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a printing system according to the present invention.

FIG. 2 is a flowchart of a print processing procedure executed on the host computer side.

FIG. 3 is a flowchart of a print processing procedure executed on the printer side.

[Explanation of symbols]

 1 Host Computer (Information Processing Device) 3 Printer (Printing Device) 10 CPU (Detecting Means, Selecting Means, Compressing Means) 13 Printer Control Unit (Notifying Means, Decompressing Means)

Claims (4)

[Claims] 1. In a printing system comprising an information processing device for compressing image data and a printing device connected to the information processing device so as to be capable of bidirectional communication, a plurality of compression methods can be selected for the information processing device. And a plurality of decompression methods are selectably provided in the printing apparatus, and the information processing apparatus detects all decompression methods of the printing apparatus, and the detection means detects the decompression method. Selection means for selecting a compression method having a compression efficiency of a predetermined value or more and a minimum compression processing time from compression methods corresponding to the decompression method, and image data based on the compression method selected by the selection means. Compressing means for compressing, wherein the printing device compresses by the notifying means for notifying the information processing device of all the expansion methods of the plurality of expansion methods, and the compression means. A printing system comprising: a decompression unit that performs a predetermined decompression process on image data. 2. An information processing apparatus, which is connected to a printing apparatus so as to be capable of bidirectional communication, and which compresses image data, is provided with a plurality of selectable compression methods, and all of the printing apparatuses have the same. Detection means for detecting the decompression method, and selection means for selecting a compression method having a compression efficiency of a predetermined value or more and a minimum compression processing time from among the compression methods corresponding to the decompression method detected by the detection means. An information processing apparatus comprising: a compression unit that compresses image data based on the compression method selected by the selection unit. 3. A printing apparatus, which is connected to an information processing apparatus so as to be capable of bidirectional communication and receives image data compressed by the information processing apparatus, wherein a plurality of decompression methods are selectable for the printing apparatus. In addition, the printing apparatus further comprises notifying means for notifying the information processing apparatus of all the expansion methods of the plurality of expansion methods. 4. A printing method in which image data compressed by an information processing device is decompressed by a printing device and printed, wherein the information processing device transmits all types of decompression methods of the printing device by the printing. After requesting the device, the printing device returns all the decompression method types to the information processing device, and then the information processing device compresses from the compression methods corresponding to the decompression method of the printing device. A compression method having efficiency equal to or higher than a predetermined value and a minimum compression processing time is selected, image data is compressed by the selected compression method and transmitted to the printing apparatus, and the printing apparatus has been transmitted. A printing method characterized by decompressing and outputting image data.