JPH09188009A - Printing apparatus and data compression method in printing apparatus - Google Patents

Abstract

(57) Abstract: A printing apparatus and a data compression method in the printing apparatus capable of improving a compression rate by selecting a compression method suitable for data from a plurality of compression methods and performing compression. I will provide a. A laser beam printer discriminates a ROM 4 storing a plurality of preset compression methods and a data type discriminating function for analyzing a command of received data and discriminating a data type based on the analysis result. The CPU 3 has a compression method selection function of selecting a compression method suitable for the type of data from a plurality of compression methods stored in the ROM 4, and a data compression function of compressing data based on the selected compression method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus and a data compression method in the printing apparatus, and more specifically, to compressing data received from an external device or the like by a compression method suitable for the data to reduce the compression rate. The present invention relates to a printing apparatus suitable for improvement and a data compression method in the printing apparatus.

[0002]

2. Description of the Related Art Conventionally, as a printing apparatus such as a printer connected to an external device such as a computer, a large amount of data received from the external device via a connection cable or the like is collected to reduce the amount of the entire file, that is, so-called compression. There is a printing device having a (data compression) function. In this type of printing apparatus, when compressing some data received from an external device, the data is compressed using a predetermined compression method.

[0003]

However, in the conventional printing apparatus, since the data received from the external device is compressed by the compression method determined in advance as described above, the type of the data and the data There is a problem that, depending on the format, there is data whose compression rate does not increase so much even when compressed.

The present invention has been made in view of the above points, and it is possible to improve the compression rate by selecting a compression method suitable for data from a plurality of compression methods and performing compression. An object of the present invention is to provide a printing apparatus and a data compression method in the printing apparatus.

[0005]

In order to achieve the above-mentioned object, the invention of claim 1 uses a plurality of preset compression methods in a printing apparatus which compresses data received from an external device or the like. The stored compression method storage means, the data type determination means for analyzing the received data command and determining the data type based on the analysis result, and the compression method suitable for the determined data type are the compression method storage means. It is characterized by comprising a compression method selection means for selecting from a plurality of compression methods stored in, and a data compression means for compressing data based on the selected compression method.

In order to achieve the above-mentioned object, the invention of claim 2 is a printing apparatus adapted to compress data received from an external device or the like, and a compression method storage means for storing a plurality of preset compression methods. And an object generating means for expanding the received data to generate an object,
A method for searching the form of the generated object and selecting a compression method suitable for the form of the searched object from a plurality of compression methods stored in the compression method storage means, and data based on the selected compression method. And a data compression means for compressing the data.

In order to achieve the above object, the invention of claim 3 is a data compression method in a printing apparatus which compresses data received from an external device or the like, and analyzes the command of the received data and the analysis. A data type determination step of determining the type of data based on the result, a compression method selection step of selecting a compression method suitable for the determined data type from a plurality of preset compression methods, and data based on the selected compression method. And a data compression step of performing the compression.

In order to achieve the above object, the invention of claim 4 is a data compression method in a printing apparatus which compresses data received from an external device or the like, and expands the received data to generate an object. An object generation step, a compression method selection step of searching the shape of the generated object and selecting a compression method suitable for the searched object shape from a plurality of preset compression methods, and data based on the selected compression method And a data compression step of performing the compression.

[0009]

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

(1) First Embodiment First, the internal structure of a laser beam printer (hereinafter abbreviated as LBP) as a printing apparatus according to the first embodiment is shown in FIG.
It will be described based on. The LBP includes an LBP body 21, an operation panel 22, a printer control unit 23, a laser driver 24, a semiconductor laser 25, and a rotary polygon mirror 26.
, Reflecting mirror 27, electrostatic drum 28, and developing unit 2
9, a paper cassette 30, a paper feed roller 31, a transport roller 32, and a transport roller 33. The LBP can register a character pattern and a fixed form (form data) from a data source (not shown).

The structure and function of each of the above parts will be described in detail.
The BP main body 21 inputs and stores character information (character code), form information, macro commands, etc. supplied from a host computer (see FIG. 1) connected to the outside of the LBP, and based on these information. A corresponding character pattern, form pattern, or the like is created, and an image is formed on a recording medium, which is recording paper. The operation panel 22 includes switches for the operator to perform various operations and a display unit such as an LED display for displaying messages and the like. The printer control unit 23 controls the entire LBP main body 21, analyzes the character information and the like supplied from the host computer, and mainly converts the character information into a video signal of a corresponding character pattern, and the laser driver 24. Output to.

The laser driver 24 is a semiconductor laser 25.
Is a circuit for driving the printer control unit 2
Semiconductor laser 25 in accordance with the video signal input from
The laser light H emitted from is switched on / off. The semiconductor laser 25 emits laser light H toward the rotary polygon mirror 26 based on the driving by the laser driver 24. The rotary polygon mirror 26 allows the laser light H emitted from the semiconductor laser 25 to be horizontally swung so that the laser light H enters the reflecting mirror 27. The reflecting mirror 27 is the rotary polygon mirror 2.
The laser light H that has entered through 6 is reflected and irradiated onto the surface of the electrostatic drum 28. The electrostatic drum 28 scans the electrostatic drum 28 with the laser light H emitted through the rotary polygon mirror 26 and the reflecting mirror 27, so that the electrostatic drum 28 has an electrostatic character pattern. A latent image is formed.

The developing unit 29 is arranged around the electrostatic drum 28 and develops the electrostatic latent image formed on the electrostatic drum 28. The developed electrostatic latent image is a recording paper. Is transferred to. The paper cassette 30 is the LBP main body 2
It is removably attached to the recording medium 1 and accommodates a plurality of cut sheet recording sheets. The paper feed roller 31 takes in the cut sheet recording paper stored in the paper cassette 30 one by one into the LBP main body 21. The conveying roller 32 and the conveying roller 33 are LB by the paper feeding roller 31.
The cut sheet recording paper taken into the P body 21 is supplied to the electrostatic drum 28.

Next, the configuration centered on the printer controller of the LBP according to the first embodiment will be described with reference to FIG. The printer controller 1 is installed in the printer control unit 23 described above, and includes a host I / F (interface) 2, a CPU 3, a ROM 4, and a DMA.
(Direct Memory Acces) 5, panel section 6, and I /
The F (interface) circuit 7, the RAM 8 and the address data bus 9 are provided. An external device 10 such as a host computer and an engine 11 are connected to the printer controller 1.

The configuration and function of each of the above-described units will be described in detail. The host I / F 2 has a reception buffer unit, and transmits / receives data to / from the external device 10. The CPU 3 controls each part of the printer controller 1 based on the program. RO
The M4 stores a program for controlling the printer controller and the like, and data relating to a plurality of compression methods (compression methods 1, 2, 3) described later. The DMA 5 is controlled by the CPU 3. The panel section 6 is connected to the switches and the LED display device of the operation panel 22 described above. I / F circuit 7
Is provided with an output buffer section for storing data to be sent to the engine 11. The RAM 8 stores various data. The address data bus 9 is used for transmitting signals from the above-mentioned respective parts.

Next, the data compression processing according to the first embodiment will be described with reference to the flowchart of FIG.

When the external device 10 transmits predetermined data to the LBP printer controller 1 (step SA
1), the CPU 3 of the printer controller 1 is the host I /
Data is received via the reception buffer unit of F2 (step SA2), and the command of the received data is analyzed (step SA3). In this case, it is assumed that the command includes a command capable of discriminating data types. The data type refers to, for example, character data, multivalued data, binary data, or the like.

After the CPU 3 of the printer controller 1 analyzes the data command, the CPU 3 determines the data type based on the analysis result (step SA4), and selects the compression method according to the data type as described later. . In the present embodiment, as the data type, only character data, multi-valued data, and binary data are handled, but the present invention is not limited to this.

When the CPU 3 of the printer controller 1 determines in step SA4 that the data type is character data, it selects a compression method effective for character data from a plurality of compression methods preset and stored in the ROM 4. A search is performed (step SA5), and compression method 1 is selected as the compression method for character data (step SA6).

Further, the CPU 3 of the printer controller 1
When it is determined in step SA4 that the data type is multi-valued data, the effective compression method for multi-valued data is searched from the plurality of compression methods preset and stored in the ROM 4 (step SA7). The compression method 2 is selected as the compression method for multi-valued data (step SA8).

Further, the CPU 3 of the printer controller 1
When it is determined in step SA4 that the data type is binary data, the effective compression method for binary data is retrieved from the plurality of compression methods preset and stored in the ROM 4 (step SA9). , The compression method 3 is selected as the compression method of the binary data (step SA1).
0).

The CPU of the printer controller 1
If the data type is character data, 3 is used to compress the character data using the compression method 1 selected in step SA6. If the data type is multi-valued data,
Multivalued data is compressed using the compression method 2 selected in step SA8. If the data type is binary data, compression of binary data is performed using the compression method 3 selected in step SA10. Do (step SA11),
This process ends (step SA12).

In the first embodiment, three compression methods (compression methods 1, 2, and 3) have been taken as an example of the compression method, but the compression method is not limited to three, and any compression method can be used. It can be the number.

As described above, according to the first embodiment, the LBP analyzes the command of the received data and the ROM 4 storing a plurality of preset compression methods, and the data based on the analysis result. Data type discrimination function for discriminating the type of data, a compression method selection function for selecting a compression method suitable for the discriminated data type from a plurality of compression methods stored in the ROM 4, and data compression based on the selected compression method. Since the CPU 3 having the data compression function is provided, it is possible to select the compression method suitable for the data and perform the compression, and it is possible to improve the compression rate. As a result, it is possible to eliminate the problem that there is data whose compression rate does not increase so much when compressed as in the past, depending on the type and format of the data.

(2) Second Embodiment An LBP according to the second embodiment has an LBP main body 21, an operation panel 22, a printer control unit 23, as in the first embodiment. A laser driver 24, a semiconductor laser 25, a rotary polygon mirror 26, a reflecting mirror 27,
The electrostatic drum 28, the developing unit 29, the paper cassette 30, the paper feed roller 31, the transport roller 32, and the transport roller 33 are provided (see FIG. 2 above).

The printer controller 1 according to the second embodiment has a host I / F 2, a CPU 3, a ROM 4, a DMA 5, and a DMA 5, as in the first embodiment.
The panel unit 6, the I / F circuit 7, the RAM 8 and the address data bus 9 are provided. The printer controller 1 includes an external device 1 such as a host computer.
0 and the engine 11 are connected (see FIG. 1 above). The detailed configuration of each of the above units is the same as that of the first embodiment described above, and thus the description thereof is omitted.

Next, the data compression processing according to the second embodiment will be described with reference to the flowchart of FIG.

When the external device 10 transmits predetermined data to the LBP printer controller 1 (step SB
1), the CPU 3 of the printer controller 1 is the host I /
Data is received via the reception buffer unit of F2 (step SB2), the command of the received data is analyzed, and data processing according to the command is performed (step S2).
B3). In this case, the data is assumed to include a command and the like.

After performing the above-mentioned data processing, the CPU 3 of the printer controller 1 expands the data to generate an object (a combination of the data value and the procedure related thereto) (step SB4). In this case, it is assumed that the object includes character data, multivalued data, binary data, and the like.

After generating the object, the CPU 3 of the printer controller 1 searches the form of the generated object and determines a compression method suitable for the form of the searched object (step SB5). In this case, it is assumed that a plurality of compression methods are stored in the ROM 4 and which compression method is effective for a certain pattern is determined in advance. The method of searching for the form of the object does not matter.

When the CPU 3 of the printer controller 1 determines that the compression method suitable for the form of the object searched in the step SB5 is the compression method 1, the CPU 3 selects the compression method 1 (step SB6).

Further, the CPU 3 of the printer controller 1
When it is determined that the compression method suitable for the form of the object searched in step SB5 is the compression method 2, the compression method 2 is selected (step SB).
7).

Further, the CPU 3 of the printer controller 1
When it is determined that the compression method suitable for the form of the object searched for in step SB5 is the compression method N, the compression method 3 is selected (step SB).
8).

The CPU of the printer controller 1
In step 3, the data is compressed by using the compression method selected in step SB6, step SB7, or step SB8 (step SB9), and this process ends (step SB10).

In the second embodiment, three types of objects are taken as an example, but the number of types of objects is not limited to this, and the number of types of objects can be arbitrary. Further, although the object and the compression method are made to correspond to each other on a one-to-one basis, the invention is not limited to this. The method of searching for the form of the object may be either a method of searching a part of the object or a method of searching the entire object.

As described above, according to the second embodiment, the LBP has a ROM 4 storing a plurality of preset compression methods, an object generating function for decompressing received data to generate an object, The form of the generated object is searched, and a compression method selection function for selecting a compression method suitable for the searched form of the object from a plurality of compression methods stored in the ROM 4, and data compression based on the selected compression method. Since the CPU 3 having the data compression function is included, it is possible to select a compression method suitable for the form of the object in which the data is expanded and perform compression, and it is possible to improve the compression rate. As a result, it is possible to eliminate the problem that there is data whose compression rate does not increase so much when compressed as in the past, depending on the type and format of the data.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus. In this case, by reading a storage medium storing a program represented by software for achieving the present invention into the system or the apparatus, the system or the apparatus can enjoy the effects of the present invention. Becomes

[0038]

As described above, according to the first aspect of the present invention, the printing apparatus analyzes the command of the received data and the compression method storage means which stores a plurality of preset compression methods. Data type discrimination means for discriminating the data type based on the analysis result, compression method selection means for selecting a compression method suitable for the discriminated data type from a plurality of compression methods, and data compression based on the selected compression method. Since it is provided with a data compression means for performing compression, it is possible to select a compression method suitable for the data and perform compression, and it is possible to improve the compression rate. As a result, it is possible to eliminate the problem that there is data whose compression rate does not increase so much when compressed as in the past, depending on the type and format of the data.

According to the second aspect of the present invention, the printing apparatus includes a compression method storage unit that stores a plurality of preset compression methods, an object generation unit that expands the received data to generate an object, and a generation unit. And a data compression unit for compressing the data based on the selected compression method. The compression method selection unit selects a compression method suitable for the searched object form and selects a compression method suitable for the searched object form. Therefore, it is possible to select a compression method suitable for the form of the object in which the data is expanded and perform compression, and it is possible to improve the compression rate. As a result, it is possible to eliminate the problem that there is data whose compression rate does not increase so much when compressed as in the past, depending on the type and format of the data.

According to the third aspect of the invention, the data compression method in the printing apparatus analyzes the command of the received data and determines the data type based on the analysis result, and the determined data type. Since it has a compression method selection step of selecting a compression method suitable for the above from a plurality of preset compression methods and a data compression step of compressing the data based on the selected compression method, the compression method suitable for the data It becomes possible to perform compression by selecting a method, and the compression rate can be improved. As a result, it is possible to eliminate the problem that there is data whose compression rate does not increase so much when compressed as in the past, depending on the type and format of the data.

According to a fourth aspect of the present invention, a data compression method in a printing apparatus is an object generating step of expanding received data to generate an object, a form of the generated object and a form of the searched object. Since it has a compression method selection step of selecting a compression method suitable for the above from a plurality of preset compression methods and a data compression step of compressing the data based on the selected compression method, It is possible to select a compression method suitable for the above mode and perform compression, and it is possible to improve the compression rate. As a result, it is possible to eliminate the problem that there is data whose compression rate does not increase so much when compressed as in the past, depending on the type and format of the data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration centering on a printer controller of a laser beam printer according to first and second embodiments of the present invention.

FIG. 2 is a cross-sectional view showing an internal configuration of the laser beam printer according to the first and second embodiments of the present invention.

FIG. 3 is a flowchart showing a flow of data compression processing according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing a flow of data compression processing according to the second embodiment of the present invention.

[Explanation of symbols]

1 printer controller 3 CPU (data type discrimination means, compression method selection means,
Object generation means, data compression means) 4 ROM (compression method storage means) 10 External device 21 LBP main body (printing device)

Claims (4)

[Claims] 1. A printing apparatus configured to compress data received from an external device or the like, and a compression method storage unit that stores a plurality of preset compression methods, and a command of the received data, and A data type discriminating means for discriminating the data type based on the analysis result; a compression method selecting means for selecting a compression method suitable for the discriminated data type from a plurality of compression methods stored in the compression method storing means; And a data compression unit that compresses data based on the compression method described above. 2. A printing apparatus adapted to compress data received from an external device or the like, and a compression method storing means for storing a plurality of preset compression methods, and an object generated by expanding the received data. Object generation means for selecting, a compression method selection means for searching a form of the generated object and selecting a compression method suitable for the searched object form from a plurality of compression methods stored in the compression method storage means, And a data compression unit that compresses data based on the compression method described above. 3. A data compression method in a printing apparatus, which compresses data received from an external device or the like, analyzes a command of the received data, and determines a data type based on the analysis result. A step of selecting a compression method suitable for the determined data type from a plurality of preset compression methods, and a data compression step of compressing data based on the selected compression method. A method for compressing data in a printing device having a feature. 4. A data compression method for a printing apparatus, which compresses data received from an external device or the like, and an object generating step of expanding the received data to generate an object, and searching a form of the generated object. And a compression method selection step of selecting a compression method suitable for the form of the searched object from a plurality of preset compression methods, and a data compression step of compressing data based on the selected compression method. A method for compressing data in a printing device having a feature.