JPH07266633A - Printer - Google Patents

Abstract

PURPOSE:To provide a printer excellent in workability automatically judging whether the compression of data is necessary to reduce the time required in the whole of printing processing. CONSTITUTION:A printing control part 15 has an image developing means 5 obtaining bit map data, a transmission method selection means 16 sampling a part of bit map data to subject the same to encoding/compression processing and estimating whether the printing time at the time of compression exceeds the printing at the time of non-compression to select a transmission method and a transmission execution means 17 using the transmission method selected by the transmission method selection means 16 to transmit the bit map data to a printer part 14 through an encoding compression means 7 or directly. A transmission method judging means 18 is constituted so that the printer part 14 judges whether data is compressed and, in the case of compression, the bit map data is outputted to a decoding means 11 and, in the case of non- compression, the bit map data is outputted as it is. This means 18 and a printing execution means 12 using the obtained bit map data to execute printing processing are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer for transferring and printing bit map data obtained by developing a character code / control command as an image.

[0002]

2. Description of the Related Art In recent years, in order to improve printing speed and printing quality, various printing apparatuses such as a page printer and a laser printer which collectively print a predetermined amount such as a unit page have been developed.

A conventional printing device will be described below.
FIG. 3 is a functional block diagram of a conventional printing device. Reference numeral 1 is a conventional printer, 2 is a printer unit that constitutes the printer 1, and actually executes printing, and 3 is a printer that constitutes the printer 1.
A print control unit 4 for exchanging character codes, control commands, etc. sent to the printer unit 2 into a printable format, and an input line 4 for sending character codes, control commands, etc. to the print control unit 3. Reference numeral 5 designates a print control unit 3, and an image expansion for expanding character codes, control commands, etc. input from the input line 4 into bitmap data printable by the printer unit 2 for each predetermined amount such as a unit page or unit block. means,
6 is a bit map image memory which constitutes the print control unit 3 and stores the bit map data output from the image developing means 5, and 7 is the print control unit 3 which is stored in the bit map image memory 6. Encoding / compressing means for sequentially encoding / compressing bitmap data, and 8 is a print controller 3.
And a first communication unit for transmitting the bitmap data compressed by the encoding / compression unit 7 to the printer unit 2, and the like.
Reference numeral 9 is a connecting line for connecting the print control unit 3 and the printer unit 2 to each other for data communication, and 10 is a unit for configuring the printer unit 2 for receiving data sent from the print control unit 3. A second communication means 11, a decoding means 11 which constitutes the printer unit 2 and expands / decodes the compressed bitmap data output from the second communication means 10, and 12 constitutes the printer unit 2 and decodes it. It is a print execution unit that prints on a medium (not shown) such as paper based on the printable bitmap data output from the conversion unit 11.

The operation of the conventional printing apparatus having the above structure will be described below. First, when a character code for designating a character to be printed, spacing, drawing, etc., a control command, etc. are input via the input line 4, the image developing means 5 of the print control unit 3 causes the character to be printed. By selecting the image corresponding to the code, interpreting the control command, etc., it is expanded into bitmap data that can be printed by the printer unit 2 for each predetermined amount of unit pages, unit blocks, etc. The image is stored in the image memory 6. Next, the encoding / compression unit 7 of the print control unit 3 sequentially encodes and compresses the bitmap data stored in the bitmap image memory 6 in order to reduce the amount of data. Next, the first communication unit 8 of the print control unit 3 transfers the bitmap data compressed by the encoding compression unit 7 to the connection line 9
To the printer unit 2 via the. Next, the printer unit 2
The second communication means 10 receives the compressed bitmap data input from the connection line 9. Next, the decoding means 11 of the printer unit 2 sequentially expands / decodes the compressed bitmap data received by the second communication means 10 to obtain printable bitmap data. Next, the print executing means 12 of the printer unit 2 causes the decoding means 1
A desired image is formed on a medium (not shown) such as paper based on the bitmap obtained in 1. Here, assuming that the bit map data can be reduced to 1 / N by the compression by the encoding / compression means 7 of the print control unit 3, the time required for data communication between the first communication means 8 and the second communication means 10 is also increased. It becomes 1 / N. As a result, in the conventional printing apparatus 1, the amount of data transferred from the print control unit 3 to the printer unit 2 is compressed, and the first communication unit 8 and the second communication unit 10 are compressed.
The time required for data transfer between the printers is shortened, and the time required for the entire printing process in the printer 1 is shortened.

[0005]

However, in the above-mentioned conventional configuration, when the amount of data to be processed increases as the resolution of the printing apparatus increases, the colorization, the gradation printing, etc., depending on the contents of the data, the data may be uniformly distributed. The effect of compression is reduced by simply compressing the data, and the amount of compressed data and the amount of non-compressed data become approximately equal, so the time required for data transfer cannot be reduced, and conversely the data compression -Since the time required for decoding increases, the time required for the entire printing process may become longer than the time required for simply transferring data without compressing / decoding data. There is a problem that the required time increases and workability is lacking.

The present invention solves the above-mentioned conventional problems, and it is possible to automatically determine whether or not data compression is required according to the content of data, and reduce the time required for the entire printing process. An object of the present invention is to provide a printing device having excellent workability.

[0007]

In order to achieve this object, a printer according to a first aspect of the present invention provides a printer unit for actually executing printing, an input character code, a control command and the like. A printing device comprising a print control unit for converting into a printable format by a printer unit, wherein the print control unit receives input character codes, control commands, etc. as a unit page, unit block, etc. Image expansion means for expanding into printable bit map data for each predetermined amount, and a part of the bit map data expanded by the image expansion means is sampled and encoded / compressed for printing at the time of compression. A transfer method selecting means for selecting a transfer method that is estimated to have a short printing time by estimating whether the time exceeds the printing time required for non-compression, and a bitmap data output from the image expanding means. Encoding / compressing means for encoding / compressing data and bit map data output from the image expanding means by using the transfer method selected by the transfer method selecting means via the encoding / compressing means or directly to the printer. Whether the data transferred from the print control unit has been compressed, and a decoding unit that has a transfer execution unit that transfers the compressed bitmap data to the printer unit The transfer method determining means for outputting to the decoding means if determined and compressed, and the bitmap data as it is for non-compressed, and the bitmap data output from the transfer method determining means or the decoding means The printing apparatus according to claim 2, further comprising: a printing execution unit that executes printing processing using the printing apparatus.
A printing apparatus comprising: a printer unit that actually executes printing; and a print control unit that converts input character codes, control commands, etc. into a format printable by the printer unit. An image expanding unit that expands the input character code, control command, and the like into bitmap data that can be printed in a predetermined amount such as a unit page or unit block, and a bitmap expanded by the image expanding unit. An encoding / compression means for sequentially encoding / compressing data,
The bit map data that has been compressed by the encoding / compression means is transferred to the printer section, the compression efficiency in the encoding / compression means is detected, and when the compression efficiency is below a predetermined threshold value, the image expansion means is executed. A decoding means for decoding the bitmap data compressed by the printer part, the transfer executing means for directly transferring the bitmap data output from the printer part to the printer part without compression, and the print control. A transfer method determining means for outputting to the decoding means if the data transferred from the unit is compressed, and outputting it to the decoding means if it is not compressed; and the transfer method determining means. Alternatively, a print execution unit that executes print processing using the bitmap data output from the decoding unit is configured.

Here, the predetermined amount of bitmap data expanded by the image expanding means may be a unit page, a unit block, or the like. Further, as a sampling method of the bitmap data in the transfer method selecting means, there is a method of arbitrarily selecting data of several lines from the bid map data. Further, as the data compression method in the transfer method selection means and the encoding compression means, a run length method, a Huffman method and the like can be mentioned. Further, as a method of estimating the required printing time in the transfer method selecting means, in the run length method, it is determined whether the number of inversions from the black pixel to the white pixel and from the white pixel to the black pixel is a predetermined value or less. For the Huffman method and the like, there is a method of checking the occurrence frequency of the bit arrangement pattern and determining whether or not the degree of the distribution reaches a certain value. As a data decompression / decoding method in the decoding means, a method corresponding to the data compression method in the coding / compression means is used. Further, as the method of detecting the compression efficiency in the transfer execution unit, the same method as the method of specifying the required printing time by the transfer method selecting means is used. Also, the images to be printed include binary images, color images,
A gradation image or the like is used.

[0009]

With this configuration, the image expansion means of the print control unit expands the character code, the control command and the like into bitmap data, and the transfer method selection means samples a part of the bitmap data and compresses it. However, it is estimated whether the time required for printing when the entire bitmap data is compressed exceeds the time required for printing when uncompressed, and if it exceeds, it is selected to perform data transfer without compression and the transfer execution means Depending on the transfer method selected by the transfer method selecting means, the bit map data is compressed by the encoding / compressing means or transferred to the printer section without being compressed, and the transfer method determining means of the printer section prints. It is determined whether the bitmap data transferred from the control means has been compressed, and if it has been compressed, the decoding means
This bitmap data is decompressed / decoded to obtain bitmap data, and in the case of non-compression, it is necessary to compress the bitmap data by executing printing as the bitmap data as it is by the print execution means. Estimate the printing time and the printing time required when the bitmap data is not compressed, and automatically select the method that seems to require a short printing time to transfer the data. Can be reduced. Also,
Similarly, the image expansion unit of the print control unit obtains the bitmap data, the encoding / compression unit sequentially compresses the bitmap data, and the transfer execution unit outputs the bitmap data compressed by the encoding / compression unit. When the compression efficiency in the encoding / compression means is detected while it is transferred to the printer section and becomes lower than a predetermined threshold value, the bitmap data output from the image expansion means is directly uncompressed to the printer. Then, the printer unit determines whether the bitmap data transferred from the print control unit is compressed or uncompressed as described above, and the bitmap data is transmitted in order to execute printing. It is possible to accurately estimate the required printing time when the bitmap data is compressed and the required printing time when it is not compressed by detecting the compression efficiency while sequentially searching It can be reduced as the body.

[0010]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram of a printer according to the first embodiment of the present invention. 4 is an input line, 5
Is an image expanding means, 6 is a bitmap image memory, 7 is an encoding / compressing means, 8 is a first communication means, 9 is a connecting line, 10
Is a second communication means, 11 is a decryption means, and 12 is a print execution means. Since these are the same as those in the conventional example, description thereof will be omitted. 13 is a printing device according to an embodiment of the present invention,
Reference numeral 14 is a printer unit that prints based on compressed bitmap data or uncompressed bitmap data sent out through the connection line 9, and 15 is bitmap data according to the compression efficiency of the sampled bitmap data. Is sent to the connection line 9 in a compressed or non-compressed form, and the print controller 15 constitutes a print controller 15 and encodes the data obtained by sampling a part of the bitmap data in the bitmap image memory 6. It is estimated whether the time required for printing when compressing the entire bitmap data exceeds the time required for printing when not compressed. If this exceeds, the transfer method by non-compression is selected. Otherwise, the transfer method by compression is selected. Transfer method selection means, and 17 a transfer method selection means 1
When the method of compression in 6 is selected, the bitmap data stored in the bitmap image memory 6 is compressed via the encoding / compression means 7 and output to the first communication means 8 for transfer method selection means. When the non-compression method is selected in 16, transfer execution means for directly outputting the bitmap data to the first communication means 8 without compression, and 18 for the printer unit 1
4 and determines whether the data sent to the second communication means 10 has been compressed. If the data has been compressed, a decoding process is performed via the decoding means 11 to convert it to bitmap data. It is a transfer method determination means that outputs the bitmap data to the print execution means 12 and directly outputs the bitmap data to the print execution means 12 in the case of non-compression.

The operation of the printing apparatus of the first embodiment of the present invention constructed as above will be described below. First, similarly to the conventional example, a character code / control command for instructing designation / spacing / drawing etc. of a character input from the input line 4 is bitmapped by the image expanding means 5 of the print control unit 15. It is developed into data and the obtained bitmap data is stored in the bitmap image memory 6. Here, as an example, the size of the paper used as the printing medium is a letter having a width of 8.5 inches and a length of 11 inches, and the printing resolution is 300 dots per inch (dot per i).
nch, abbreviated as dpi hereinafter), and assuming that one page of a binary image of 300 dpi in length is given, the bitmap image memory 6 stores data of 2550 dots per horizontal line and 3300 lines in vertical direction, which is about 8 megabits. It will be remembered. Next, the transfer method selection means 16 samples a part of the bitmap data from the bitmap image memory 6 and compresses the obtained data to estimate the compression efficiency. Here, as an example, image data at an arbitrary position of 10 lines is selected from the above-mentioned bitmap data of about 8 megabits, and this data is used in a run length method generally used in a facsimile apparatus, that is, Paying attention to how many white pixels and black pixels are continuous, compression is performed by the method of encoding and compression, and black pixel to white pixel and white pixel to black pixel are selected for each selected line. The number of inversions is stored as n1 to n10, and n1
The average value of n to n10 is calculated as na. If the value of na exceeds the threshold value nx calculated by (Equation 1), it is estimated that if the compression process is performed, the time required for the entire printing process will be longer than that in the case of the non-compression. The transfer method selection means 16 selects an uncompressed data transfer method, and otherwise selects a compressed data transfer method.

[0012]

[Equation 1]

In (Equation 1), dt is the number of pixels per line of the sampled data, and t1 is a requirement for transferring uncompressed bitmap data for one pixel from the print control unit 15 to the printer unit 14. Time, t2 is a time required to print the uncompressed bitmap data for one pixel by the printer unit 14, and t3 is one encoding of the compressed bitmap data obtained by encoding / compressing the bitmap data. The time required to transfer the unit from the print control unit 15 to the printer unit 14, t4 is one encoded unit of the compressed bitmap data, which is decoded by the printer unit 14 in the same manner as t3, obtains the bitmap data, and is printed. The time required for processing, t5, is the time required for encoding and compressing bitmap data for one encoding unit. Next, the transfer executing means 17 according to the transfer method selected by the transfer method selecting means 16, when transferring the data without compression,
When the bitmap data in the bitmap image memory 6 is directly sent from the first communication unit 8 to the printer unit 14 and compressed and transferred, the bitmap data in the bitmap image memory 6 is encoded / compressed. Compression processing is performed via the first communication means 8 and is sent to the printer unit 14. Next, the second communication means 10 of the printer unit 14 receives the data input from the connection line 9. Next, the transfer method determination means 18 determines whether or not the data received by the second communication means 10 has been compressed. If the data is uncompressed, the uncompressed bitmap data is directly printed and executed. If the compressed data has been transmitted to the second communication means 10 and has been compressed, the data received by the second communication means 10 is decompressed / decoded via the decoding means 11 to obtain bitmap data, which is then transmitted. It is sent to the print executing means 12. next,
The print execution means 12 forms a desired image on a medium (not shown) such as paper based on the transmitted bitmap data in the same manner as in the conventional example.

As described above, according to the present embodiment, the transfer method selection means 16 of the print control unit 15 samples a part of the bitmap data, compresses this, and based on the result, the entire bitmap data. The printing time required for compression and the printing time required for non-compression are estimated, the data transfer method with the shortest time is selected, and the transfer execution means 17 is selected.
However, depending on the transfer method selected by the transfer method selection means 16, the bitmap data is sent to the printer unit 14 in a compressed or non-compressed state, and the transfer method determination means 1 of the printer unit 14 is sent.
8 determines whether or not the data sent from the print control unit 15 has been compressed. If the data has been compressed, it is decoded by the decoding means 11 and sent to the print executing means 12, otherwise it is directly a non-compressed bitmap. By sending the data to the print execution means 12, the time required for printing when compressed and when not compressed at the time of data transfer is estimated, and the data is automatically transferred by a method which seems to be short. Therefore, the time required for the entire printing process can be reduced.

Although the run length method is used as the data compression method in this embodiment, the Huffman method or the like may be used. At that time, transfer method selecting means 1
The method of detecting the compression efficiency in 6 may be to check the occurrence frequency of the pattern of bit arrangement and determine whether or not the degree of the distribution reaches a constant value. Further, although the binary image is used as the image to be printed, it may be a gradation print, a colorized image, or the like.

(Embodiment 2) Hereinafter, a printer according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a functional block diagram of the printing apparatus according to the second embodiment of the present invention. 4 is an input line, 5 is an image developing means,
6 is a bit map image memory, 7 is an encoding / compression means, 8
Is a first communication means, 9 is a connection line, 10 is a second communication means, 11 is a decoding means, 12 is a print execution means, 14 is a printer section, 18 is a transfer method determination means, and these are embodiments. Since it is the same as No. 1, the same reference numerals are given and the description is omitted. Reference numeral 19 is a printing device according to the second embodiment of the present invention, and 20 is a method for detecting the data compression efficiency while searching the bitmap data and transferring the bitmap data to the printer unit 14 using a transfer method corresponding to the data compression efficiency. The print control unit 21 for performing the above-described processing sequentially encodes and compresses the bitmap data in the bitmap image memory 6 by the encoding / compression unit 7, and sequentially outputs the compressed bitmap data that is output to the first communication unit 8. At the same time, the compression efficiency of this compressed bitmap data is detected, and when this compression efficiency becomes less than or equal to a predetermined threshold value, the compression processing by the encoding / compression means 7 is interrupted and the subsequent bitmap data is bit-coded. It is a transfer execution means that directly takes out from the map image memory 6 and sends it to the first communication means 8 without compressing it.

The operation of the printing apparatus according to the second embodiment of the present invention constructed as above will be described below. First, in the same manner as in the first embodiment, the image expansion means 5 of the print control unit 20 expands the character code, control command, etc. input from the input line 4 into bitmap data, and stores this in the bitmap image memory 6. Remember. Here, as in the first embodiment, the paper size is letter and the resolution is 300 horizontal.
It is assumed that binary image data of dpi, vertical 300 dpi is stored in the bitmap image memory 6 for one page, that is, bitmap data of about 8 megabits of horizontal 1 line 2550 pixels and vertical 3300 pixels. Next, the encoding / compressing means 7 sequentially encodes / compresses the bitmap data in the bitmap image memory 6 and transfers it.
Send to. Here, according to the run length method, 1
Encoding and compression are performed for each line, and the number n of inversions from white pixels to black pixels and from black pixels to white pixels is counted. Next, the transfer execution means 21 transfers the compressed bitmap data sequentially sent from the encoding compression means 7 to the first communication means 8.
When the compression efficiency in the encoding / compression means 7 becomes equal to or lower than a predetermined threshold value, the compression is stopped and the bitmap data in the bitmap image memory 6 is directly transmitted to the first communication. To the means 8. Here, the value of the number of inversions n counted by the encoding compression means 7 is (Equation 2)
It is estimated that if the compression process is performed when the threshold value nx 'calculated in step 1 is exceeded, the time required for the entire printing process will be longer than that in the non-compression process. The data is directly sent to the first communication means 8 from the bitmap image memory 6 without being compressed.

[0018]

[Equation 2]

In (Equation 2), dt is the number of pixels per line in the bitmap data, and t1 is a required value for transferring uncompressed bitmap data for one pixel from the print control unit 20 to the printer unit 14. Time, t2 is a time required to print the bitmap data for one pixel in the printer unit 14, and t3 is one transfer unit for encoding one bit of the compressed bitmap data from the print control unit 20 to the printer unit 14. The required time, t4, is the required time for decoding one encoding unit of the compressed bitmap data by the printer unit 14 and performing the printing process. Next, the first communication means 8
The compressed or uncompressed bitmap data output from the transfer execution means 21 is sent to the printer unit 14. Next, in the same manner as in the first embodiment, the printer unit 14 outputs a desired data to a medium (not shown) such as paper according to whether the bitmap data sent from the print control unit 20 is compressed or uncompressed. Form an image.

As described above, according to the present embodiment, the bit map data in the bit map image memory 6 is sequentially compressed by the encoding / compressing means 7 of the print controller 20, and the transfer executing means 21 completes the compression. The bit map data is sent to the printer unit 14, the data compression efficiency of the encoding / compression means 7 is detected, and when this falls below a predetermined threshold value, the data compression is stopped and the bit compression is performed. The bitmap data in the map image memory 6 is directly sent to the printer unit 14 without compression, and the printer unit 14 performs printing depending on whether the data sent from the print control unit 20 is compressed or uncompressed. By doing so, the compression efficiency is detected while sequentially searching the bitmap data, and the printing time required when the bitmap data is compressed and the printing time required when it is not compressed are accurately estimated. It can, it is possible to reduce the overall printing time required.

In the present embodiment, the run length method is used as the data compression method, but this may be the Huffman method or the like. At this time, the method of detecting the compression efficiency in the transfer executing means 21 may be to check the occurrence frequency of the bit arrangement pattern and determine whether or not the degree of the distribution reaches a certain value. Further, although the binary image is used as the image to be printed, it may be a gradation print, a colorized image, or the like.

[0022]

As described above, according to the present invention, the image expanding means of the print control unit expands the character code, the control command and the like into bitmap data, and the transfer method selecting means samples a part of the bitmap data. Then, this is data-compressed, and it is estimated whether the time required for printing when the entire bitmap data is compressed exceeds the time required for printing when uncompressed, and if it exceeds, it is selected to transfer the data uncompressed. Then
Depending on the transfer method selected by the transfer method selection means, the transfer execution means either compresses the bitmap data by the encoding / compression means or transfers it to the printer section without compression and determines the transfer method of the printer section. The means determines whether or not the bitmap data transferred from the print control means has been compressed, and if it has been compressed, the decoding means decompresses / decodes the bitmap data to generate a bitmap. When data is obtained and uncompressed, the print time is used as the bitmap data as it is by the print execution means, and the print time required when the bitmap data is compressed and the bitmap data is not compressed. Print processing to estimate the printing time required for printing and automatically select the method that seems to require a short printing time for data transfer. The time required for the body can be reduced and the workability is excellent. Similarly, the image expansion means of the print control unit obtains the bitmap data, and the encoding / compression means sequentially compresses the bitmap data and transfers the data. The means transfers the bitmap data that has been compressed by the encoding / compression means to the printer unit, detects the compression efficiency in the encoding / compression means, and when the compression efficiency is below a predetermined threshold value, the image The bitmap data output from the decompressing unit is directly transferred to the printer unit without compression, and the printer unit, as described above, has the bitmap data transferred from the print control unit compressed or uncompressed. In order to determine whether or not to print, the compression efficiency is detected while sequentially searching the bitmap data, and the time required for printing when the bitmap data is compressed and the printing when not compressed It can accurately estimate the main time excellent reliability, in which can realize printing apparatus having excellent workability which can reduce the overall printing time required.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a printing apparatus according to a first embodiment of the present invention.

FIG. 2 is a functional block diagram of a printing device according to a second embodiment of the present invention.

FIG. 3 is a functional block diagram of a conventional printing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 printer 2 printer section 3 print control section 4 input line 5 image expansion means 6 bitmap image memory 7 encoding / compression means 8 first communication means 9 connection line 10 second communication means 11 decoding means 12 print execution means 13 printing device 14 printer unit 15 printing control unit 16 transfer method selection unit 17 transfer execution unit 18 transfer method determination unit 19 printing device 20 print control unit 21 transfer execution unit

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Claims (2)

[Claims] 1. A printer unit for actually executing printing, and a print control unit for converting input character codes, control commands, etc. into a format printable by the printer unit, and the like.
An image expanding means for expanding the input character code, control command, and the like into bitmap data that can be printed for each predetermined amount such as a unit page and a unit block. A part of the bit map data expanded by the image expanding means is sampled and encoded / compressed to estimate whether the printing time required for compression exceeds the printing time required for non-compression to estimate the printing time required. A transfer method selecting means for selecting a transfer method that is considered to be short, an encoding compression means for encoding and compressing the bitmap data output from the image expanding means, and a transfer method selected by the transfer method selecting means are provided. Transfer execution means for transferring the bitmap data output from the image decompression means to the printer section via the encoding / compression means or directly. The lintering unit decodes the compressed bitmap data, and a decoding unit determines whether the data transferred from the print control unit is compressed. If the data is compressed, the lintering unit outputs it to the decoding unit. If it is non-compressed, it has a transfer method determination means for outputting the bitmap data as it is, and a print execution means for executing a printing process using the bitmap data output from the transfer method determination means or the decoding means. A printing device characterized by the above. 2. A printer section for actually executing printing, and a print control section for converting input character codes, control commands, etc. into a format printable by the printer section, and the like.
An image expanding means for expanding the input character code, control command, and the like into bitmap data that can be printed for each predetermined amount such as a unit page and a unit block. Encoding compression means for sequentially encoding and compressing the bitmap data expanded by the image expanding means, and transferring the bitmap data compressed by the encoding compression means to the printer section and by the encoding compression means. And a transfer execution unit that directly transfers the bitmap data output from the image expansion unit to the printer unit without compression when the compression efficiency is detected to be equal to or less than a predetermined threshold value. Decoding means for decoding the compressed bitmap data by the printer unit, and determining whether the data transferred from the print control unit has been compressed Using the transfer method determining means for outputting to the decoding means if compressed, and the bitmap data as it is for uncompressed, and the bitmap data output from the transfer method determining means or the decoding means A printing apparatus comprising: a printing execution unit that executes a printing process.