JPH08258344A - Printing device - Google Patents

Abstract

PURPOSE: To provide a printing device in which image data are divided into a block having prescribed size and drawing may be conducted without performing rotational processing in relation to the part having symmetry wherein the pattern of the divided block data is the same after the rotation and before the rotation. CONSTITUTION: A format control part 1100 is equipped with a CPU, an ROM and an RAM. Received image data are divided into a block having prescribed size and the pattern of the divided block data is detected. When the pattern of the divided block data is the same patter as after rotation, rotation is not performed. Only in the case other than the above, rotation is performed for the divided block data. Therefore, efficient printing processing is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing device for outputting print information from an external device, for example.

[0002]

2. Description of the Related Art In a page printer, when an image is generated in a page memory, the entire printed image is printed in 90 pages depending on the page orientation (page format) and the sheet conveying direction.
It must be rotated by 180 °, 180 ° or 270 °. For example, in a printing apparatus having a mechanism for conveying the paper in the long side direction of the paper, when landscape (x-axis in the long side direction of the paper and y-axis in the short side direction) is specified in the page format, The printed image must be rotated 90 °. Image data includes various data such as character data and graphic data. Among these, image data in which color information and shading of an image are associated with bits is called image data or simply an image, and forms an image. The unit of pixel, that is, the minimum unit is called pixel,
Of the print data, only this image data has to be created by rotating the received data before the rotation.

Further, in recent years, the resolution of printing apparatuses has increased, and more precise printing has become possible. But,
The higher the resolution, the more page memory is required, but the mounting of the memory is limited in terms of cost, and therefore, a printing method is used in many printing apparatuses. Instead of having a page memory for one page (called a full paint), the memory for about half a page is divided into three band memories, for example, band 1, band 2 and band 3, and the expansion to band 1 is performed. At the end, while converting the bit data formed in band 1 into a video signal, it is possible to expand to band 2 at the same time.
Band 1 → Band 2 → Band 3 → Band 1 → Band 2 →
One page is printed by sequentially developing the band 3. However, there is a risk that printing will not be possible if data that takes time to develop is concentrated in a band that has data, or if the memory required for expansion is insufficient. For example, the bit data of band 2 cannot be converted into a video signal unless the expansion into band 2 is completed at the time when the conversion of the band 1 bit data into a video signal is completed. In order to avoid this, there is a method of reducing the resolution by thinning out the bits when the data is expanded to the band memory when there is a possibility that printing cannot be performed beforehand. For example, if an image originally formed at 600 dpi (dot / inch) is thinned out to half at 300 dpi, the memory for development is small, and the page memory is ¼ of the capacity so that the bandwidth can be widened. You can switch to full paint.

[0004]

However, in the above-mentioned conventional example, since the rotation processing of the image data is usually carried out bit by bit, it takes a very long time to perform the control by the software, which is a bottleneck in the printing processing.

Further, in the above-mentioned conventional example, when the bits are thinned out in order to reduce the resolution, depending on the thinning-out algorithm, even if the black line of 1 dot is thinned out so as not to be erased, 1d
There was a problem that the white line of ot disappeared.

The present invention has been made in view of the above-mentioned conventional example, and in the image data, a portion having symmetry such that the pre-rotation and the post-rotation are the same is drawn without performing the rotation processing. It is therefore an object of the present invention to provide a printing device capable of high speed processing.

Further, according to the present invention, after the image data is divided and rotated, and the block data after the rotation is saved / restored in the cache memory, an image can be drawn when the rotation of the same pattern is used a plurality of times. It aims at speeding up.

Further, according to the present invention, by performing bit inversion of block data, an optimum thinning process is performed on an image which is black and white inverted by one thinning algorithm, and a high quality image in which deterioration of quality is suppressed when the resolution is lowered. It is an object of the present invention to provide a printing device that can obtain the above.

[0009]

In order to achieve the above object, a printing apparatus according to claim 1 of the present invention divides received image data into blocks having a predetermined size, and dividing means by the dividing means. The pattern of the block data that has been detected and determines whether or not the pattern is the same as the pattern after rotation, and rotation is performed on the divided block data only when the determination unit determines that the pattern is not the same. And a rotation means for performing the rotation.

According to a second aspect of the present invention, in the printing apparatus according to the first aspect, the determination unit includes a block data table that is the same before and after the rotation.
By comparing the divided block data with the block data table, it is determined whether or not the block data before rotation and the block data after rotation are the same.

Further, according to a third aspect of the present invention, a printing device divides received image data into blocks of a predetermined size, rotating means for rotating the divided block data, and pre-rotation means. And the temporary storage means for storing the block data after the rotation by the rotation means, and the newly divided block data and the block data already stored in the temporary storage means are matched, the new division is performed. It is characterized in that it comprises means for taking out the block data already stored in the temporary storage means as the block data after the rotation of the block data.

Further, the printing apparatus according to claim 4 of the present invention comprises a storage means for storing the print image to be supplied to the engine portion, and a dividing means for dividing the print image into blocks of a predetermined size during the storage. It is characterized by comprising thinning means for thinning the divided block data based on a predetermined pattern to reduce the resolution, and means for inverting the bits of the block data before and after the thinning processing by the thinning means.

[0013]

The first printing apparatus according to the present invention divides the received image data into blocks of a predetermined size, detects the pattern of the divided block data, and the pattern of the divided block data is the same as that after rotation. If it is a pattern, rotation is not performed, and only in other cases, rotation is performed on the divided block data, so efficient printing processing is possible.

The second printing apparatus according to the present invention divides the received image data into blocks of a predetermined size, rotates the divided block data, and outputs the block data before and after the rotation. Since it is saved / restored in the temporary storage means, efficient print processing becomes possible.

Further, the third printing apparatus according to the present invention divides the print image into blocks of a specific size at the time of developing to a page memory or a band memory, and the divided block data is based on a specific pattern. Since thinning and resolution are lowered and the bits of the block data are inverted, high-quality printing processing is possible.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the structure of this embodiment, a laser beam printer suitable for applying this embodiment (hereinafter referred to as "LB
The description will be made with reference to FIG. 1 as well. Needless to say, the printer to which the present embodiment is applied is not limited to the laser beam printer, and may be a printer of another printing method.

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

(Embodiment 1) FIG. 1 is a sectional view showing the internal structure of a laser beam printer applied to this embodiment. This LBP is used for registering a character pattern and a fixed form (form data) from a data source (not shown). ) Etc. can be registered. In the figure, reference numeral 1000 denotes an LBP main body, which inputs and stores character information (character code) supplied from an externally connected host computer, form information, or a macro command, and responds in accordance with those information. Create character patterns, form patterns, etc.,
An image is formed on a recording paper which is a recording medium. An operation panel 1012 is provided with switches for operation and an LED display, and a printer control unit 1001 controls the entire LBP 1000 and analyzes character information supplied from the host computer. The control unit 1001 mainly converts character information into a video signal of a corresponding character pattern and outputs the video signal to the laser driver 1002. The laser driver 1002 is a semiconductor laser 1003.
Is a circuit for driving a laser beam emitted from the semiconductor laser 1003 in accordance with an input video signal.
004 is switched on and off. The laser 1004 is horizontally swung by the rotating polygon mirror 1005 and the electrostatic drum 1006.
Scan over. As a result, an electrostatic latent image having a character pattern is formed on the electrostatic drum 1006. The latent image is developed by the developing unit 1007 around the electrostatic drum 1006 and then transferred to the recording paper. A cut sheet is used as the recording sheet, and the cut sheet recording sheet is LBP1000.
It is stored in a paper cassette 1008 attached to the paper cassette 1008, is taken into the apparatus by the paper feed roller 1009 and the conveyance rollers 1010 and 1011, and is supplied to the electrostatic drum 1006.

FIG. 2 is a block diagram showing the arrangement of the printing apparatus of this embodiment.

In FIG. 2, reference numeral 2000 is a printing apparatus 1000.
Is a host computer connected to the printer 100, and prints information including print data and control codes.
It outputs to 0. The printing apparatus 1000 is roughly divided into a formatter control unit 1100, an interface 1200, an output control unit 1300, and a printer engine unit 1.
It consists of 400.

The formatter control unit 1100 includes a reception buffer 1101, a command discrimination unit 1102, a command analysis unit 1103, a command execution unit 1104, and a page memory 1.
105, a data division unit 1106, and a rotation execution unit 1107.

The reception buffer 1101 is a storage means for temporarily holding the print information received from the host computer 2000. The command discrimination unit 1102 discriminates each print control command. If the print control command is other than the image drawing command, the print data is directly analyzed by the command analysis unit 1103 and executed by the command execution unit 1104. . Command analyzer 1
Reference numeral 103 is for analyzing each print control command.

The command analyzed by the command analysis unit 1103 is an intermediate result of analysis of print data, and is converted into an intermediate code in a format that is easier to process in the command execution unit 1104. Command discrimination unit 110
When it is determined in 2 that the print control command is an image drawing command, the parameter is analyzed by the command analysis unit 1103, and then the command execution unit 1
At 104, it is determined whether rotation processing is necessary.

When the command execution unit 1104 determines that the rotation processing is necessary, the image data is divided into a certain size by the data division unit 1106, and the rotation execution unit 1107 performs the rotation processing for each division unit. The rotation execution unit 1107 uses a table, a bit shift, or the like to rotate the 90 °, 18
Bit data rotated by 0 ° and 270 ° is created. The image data processed as described above is expanded (stored) in the page memory 1105 by the command execution unit 1104. Note that, in general, the formatter control unit 1100 is composed of a computer system using a CPU, ROM, RAM, etc.
The U control procedure (including FIGS. 3, 4, and 5) is stored in the ROM.

The output control unit 1300 has a page memory 11
The contents of 05 are converted into a video signal, and the image is transferred to the printer engine unit 1400. Printer engine section 1
Reference numeral 400 is a printing mechanism unit for forming a permanent visible image on the recording paper by using the received video signal.

Next, an explanation will be given of the overall print control processing procedure in the present embodiment in the printing apparatus having such a configuration with reference to the flow charts shown in FIGS. 3, 4 and 5. S301 to S304 in FIG. 3, S401 to S411 in FIG. 4, and S501 to S50 in FIG.
Reference numeral 9 indicates each processing step.

FIG. 3 shows the main processing from the start to the end of the operation of the printing apparatus 1000. First, step S3
At 01, the print data sent from the host computer 2000 is received and stocked in the reception buffer 1101. Next, the print data stocked in the reception buffer in step S302 is read out, and then in step S3.
At 03, drawing processing is performed. Then, in step S304, it is determined whether or not a print end command is received, or whether or not the print data is ended. If the print is ended, the print operation is ended. If printing has not ended, the processing from step S301 is repeated. FIG. 4 shows the drawing process corresponding to step S303 in FIG. This process is a process for actually performing the printing process. First, in step S401, the command analysis unit 1103 checks whether or not the data is a paper discharge command. If the data is a paper discharge command, the process proceeds to step S406 and is processed. If it is not the paper discharge command in step S401, it is determined whether or not the next analyzed command is a command for expansion processing to page memory such as character printing or graphic drawing (step S402). If not, the process proceeds to step S405. , Execute the command immediately.
If so (when the process proceeds from step S402 to step S409), it is determined whether the print control command received in step S409 is an image drawing command. If it is not an image drawing command, step S4
If it is an image drawing command, it is determined whether rotation processing is necessary (step S410).
The rotation referred to here is orthogonal rotation of 90 °, 180 °, and 270 °, and is determined by parameters such as the page format and the image drawing command. If the rotation process is not necessary, the process directly proceeds to step S403. If the offset is designated, the rotation process is performed at step S411, and then the process proceeds to step S403.

In step S403, an intermediate code in a form that facilitates command execution processing is generated. Upon receiving this intermediate code, the command execution unit 1104 performs expansion processing on the page memory 1105 (step S404), and after completion of the expansion processing, returns to step S302 in FIG. 3 to repeat data analysis processing. On the other hand, if it is determined in step S401 that it is a paper discharge command, the output control unit 1300 converts the content of the page memory 1105 into a video signal for the printer engine unit 1400, and outputs the image (step S406). Printer engine unit 140
At 0, a permanent visible image is formed on the recording paper with the received video signal and printing is performed (step S407). When the printed result is ejected in step S408, the printing process for one page ends.

FIG. 5 shows the rotation process used in FIG. This process is a process of orthogonally rotating the image data to be drawn. First, in step S501, the rotation angle is 90 ° from the page format and the image deformation parameter,
Which of 180 ° and 270 ° is calculated. Next, in step S502, the image data is divided into m × m pixel blocks. Here, m is a threshold value depending on the hardware configuration. Then, after one block of data is extracted in step S503, the process proceeds to steps S504 and S505. In step S505, a pattern for one line (m × 1 pixel) from the end of the divided block is detected. In this embodiment, the rotation execution unit 1107 is provided with a block table of m × m pixels in advance, and the pattern for one line detected in step S506 is compared with one line from the end of the block table. As a result, if the pattern for one line matches the pattern for one line in the block table (S50
7) Then, the process returns to step S504, and the same process is performed for the pattern of the next one line. If there is a line that does not match the table in step S507,
Proceeding to step S508, one block is rotated by matrix calculation or a lookup table. While the pattern comparison results match in this way, the processing from step S503 to step S506 is repeated,
When the comparison for one block, that is, for m lines is completed, the process proceeds to step S509. When the comparison for one block is completed in step S504, the process proceeds to step S509 without rotating. In this way, the processes from step S503 are repeated until all the blocks divided in step S502 are completed. The block table used in this embodiment has symmetry as shown in FIG.

The operation of the entire printing apparatus has been described above.
These processes are realized by the computer system of the formatter control unit 1100.

(Second Embodiment) FIG. 7 is a block diagram showing the arrangement of a printing apparatus according to this embodiment.

In FIG. 7, reference numeral 2000 is a printing apparatus 1000.
Is a host computer connected to the printer 100, and prints information including print data and control codes.
It outputs to 0. The printing apparatus 1000 is roughly divided into a formatter control unit 1100, an interface 1200, an output control unit 1300, and a printer engine unit 1.
It consists of 400.

The formatter control unit 1100 includes a reception buffer 1101, a command determination unit 1102, a command analysis unit 1103, a command execution unit 1104, and a page memory 1.
105, a data division unit 1106, a rotation execution unit 1107,
It is composed of a cache memory 1108.

The reception buffer 1101 is a storage means for temporarily holding the print information received from the host computer 2000. The command discrimination unit 1102 discriminates each print control command. If the print control command is other than the image drawing command, the print data is directly analyzed by the command analysis unit 1103 and executed by the command execution unit 1104. . Command analyzer 1
Reference numeral 103 is for analyzing each print control command.

The command analyzed by the command analysis unit 1103 is an intermediate result obtained by analyzing the print data, and is converted into an intermediate code in a format easier to process in the command execution unit 1104. Command discrimination unit 110
When it is determined that the print control command is the image drawing command in 2, the command analyzing unit 1103 analyzes the parameter, and the image dividing unit 1106 divides the image data into a certain size. The rotation execution unit 1107 performs rotation processing.

The rotation execution unit 1107 creates rotated bit data using a table or matrix from bit data of a fixed size. The cache memory 1108 is a high-speed access that temporarily stores the block data before rotation divided by the data division unit 1106, the block data after rotation processed by the rotation execution unit, and the rotation angle and gradation accompanying them. Is a possible memory.

In general, the formatter control unit 11
00 is configured by a computer system using a CPU, a ROM, a RAM, etc., and the control procedure of this CPU (including FIG. 8) is stored in the ROM. The output control unit 1300 converts the content of the page memory 1105 into a video signal and transfers the image to the printer engine unit 1400. The printer engine unit 1400 is a printing mechanism unit for forming a permanent visible image on the recording paper by using the received video signal.

Next, in the printing apparatus configured as described above, an overall print control processing procedure in this embodiment is shown in FIG.
This will be described with reference to the flowchart shown in FIG. In addition,
The main processing from the start to the end of the operation of the printing apparatus 1000 is the same as the flowcharts shown in FIGS.

FIG. 8 shows the rotation processing used in FIG. 4, and S801 to S811 show processing steps. This process is a process of rotating the image data to be drawn.

First, in step S801, the rotation angle is calculated from the page format and the image deformation parameter.
Next, in step S802, the image data is m ×
Divide into blocks of m pixels. Here, m is a threshold value depending on the hardware configuration. Then, in step S803, 1
After extracting the block of data, step S80
4. Go to step S805. In step S805, one line (m × 1 pixel) from the end of the divided block
Detect minute patterns.

The pattern for one line detected in step S806 is compared with the one line from the end of the block pattern stored in the cache memory. This time,
At the same time, information such as the rotation angle and gradation stored together with the block pattern is also compared. It should be noted that although a plurality of block patterns can be stored in the cache memory, in step S806, comparison is made with all patterns until a matching pattern is hit. Then, in step S807, it is determined whether or not one line matches the pattern on the cache memory. If a matching pattern is found, the process from step S804 is repeated.

If no matching pattern is found in the cache memory in step S807, that is, if there is a line that does not match even one line, the process proceeds to step S808, and one block is calculated by matrix calculation or a lookup table. Do a minute rotation. When the rotation is processed in step S808, the process proceeds to step S809, and the information unit including the blocks before and after the rotation and the information such as the rotation angle and the gradation is stored in the cache memory. On the other hand, step S8
In step 04, when the comparison with the pattern on the cache memory is completed for one block, that is, for m lines, step S
In step 811, the rotated block stored in the cache memory as a pair with the matched block is extracted. After that, in step S810, it is determined whether or not the processing for all the blocks divided in step S802 is completed, and step S803 is executed until the processing for all blocks is completed.
Repeat the process from.

The operation of the entire printing apparatus has been described above.
These processes are realized by the computer system of the formatter control unit 1100.

(Third Embodiment) FIG. 9 is a block diagram showing the arrangement of a printing apparatus according to this embodiment.

In FIG. 9, reference numeral 2000 is the printing apparatus 1000.
Is a host computer connected to the printer 100, and prints information including print data and control codes.
It outputs to 0. The printing apparatus 1000 is roughly divided into a formatter control unit 1100, an interface 1200, an output control unit 1300, and a printer engine unit 1.
It consists of 400.

The formatter control unit 1100 includes a reception buffer 1101, a command discrimination unit 1102, a command analysis unit 1103, a command execution unit 1104, and a page memory 1.
105, data division unit 1106, pattern detection unit 110
9A, thinning execution unit 1109B, inversion execution unit 1109C
It is composed of The reception buffer 1101 is a storage unit that temporarily holds the print information received from the host computer 2000. The command discrimination unit 1102
The determination of each print control command is performed.

The command analysis unit 1103 analyzes each print control command. Command analysis unit 1103
The command analyzed in (1) is an intermediate result of analysis of print data, and is converted into an intermediate code in a format that is easier to process in the command execution unit 1104. The data dividing unit 1106 divides the expanded data into blocks of a specific size when resolution conversion is required when expanding from the command executing unit 1104 to the page memory 1105.

The pattern detection unit 1109A searches the pattern of the block data divided by the data division unit 1106 for each line, and turns ON (black) and OFF (white).
The number of bits is counted, and the thinning execution unit 1
A block 109B thins out bits from the block data according to a certain rule to reduce the resolution. When the pattern detection unit 1109A has more ON bits than the threshold value, the block data is inverted by the inversion execution unit 1109C, and then the thinning execution unit 1109B performs resolution conversion.

In general, the formatter control unit 11
00 is configured by a computer system using a CPU, a ROM, a RAM, and the control procedure of this CPU (including FIGS. 10 and 11) is stored in the ROM. The output control unit 1300 has a page memory 1105.
Is converted into a video signal, and the image is transferred to the printer engine unit 1400. Printer engine unit 140
Reference numeral 0 denotes a printing mechanism unit for forming a permanent visible image on the recording paper by using the received video signal.

Next, in the printing apparatus configured as described above, an overall print control processing procedure in this embodiment is shown in FIG.
0, a description will be given with reference to the flowchart shown in FIG. The main processing from the start to the end of the operation of the printing apparatus 1000 is the same as the flowchart shown in FIG.

S1001 to S1009 in FIG.
S1101 to S1111 in FIG. 11 indicate processing steps.

FIG. 10 shows the drawing process corresponding to step S303 in FIG. This process is a process for actually performing the printing process. First, in step S1001, the command analysis unit 1103 checks whether the data is a paper discharge command. If the data is a paper discharge command, the process proceeds to step S1006 to perform processing. If it is not the paper discharge command in step S1001, it is determined whether the next analyzed command is a command for expanding the page memory such as character printing or graphic drawing (step S1002). If not, the process proceeds to step S1005. , Execute the command immediately. If so (step S1002 to step S1003), step S1
At 003, an intermediate code in a form that facilitates command execution processing is generated.

Thereafter, in step S1009, resolution conversion processing is performed. Upon receiving this intermediate code, the command execution unit 1104 performs expansion processing to the page memory 1105 (step S1004), and after completion of the expansion processing, the flow returns to step S302 in FIG. 3 to repeat the data analysis processing. On the other hand, if it is determined in step S1001 that the instruction is a paper discharge instruction, the output control unit 1300 converts the content of the page memory 1105 into a video signal for the printer engine unit 1400 and outputs the image (step S).
1006). The printer engine unit 1400 forms a permanent visible image on the recording paper with the received video signal and prints it (step S1007). Then, in step S1008
When the result printed in step 1 is ejected, the print control process for each page ends.

FIG. 11 shows the resolution conversion process used in FIG. This process is a process of thinning a print image to be drawn to reduce the resolution. First, step S11
In 01, when the page memory for one page is not secured (the page memory in this case is generally called a band memory), the expansion time for expanding the intermediate code created in step S1003 into the band memory is calculated.
Next, in step S1102, the memory required for expansion, that is, the memory temporarily required for expanding the intermediate code into the print image is calculated.

Steps S1101 and S1102
In step S1103, it is determined whether the resolution conversion is necessary or not. Here, adding a description of the determination method, when expanding to a band memory,
It is necessary to perform a so-called banding process, in which the bands that have been expanded are sequentially converted into video signals, and the bands that have been converted into video signals are sequentially opened to expand the intermediate code as a band memory. However, since the expansion process of the intermediate code to a certain band memory is complicated and printing cannot be performed if the expansion process of the intermediate code catches up with the conversion process to the video signal, the expansion time calculated in advance in step S1101. Is not in time for the conversion to the above video signal, step S11
In 03, it is determined that resolution conversion is necessary. Further, even if the memory required for expansion in step S1102 is insufficient in the memory capacity that can be secured, printing is still impossible, so it is determined in step S1103 that resolution conversion is necessary. When it is determined that the resolution conversion is unnecessary in step S1103 by such a determination method, the process ends as it is.

On the other hand, if it is determined in step S1103 that resolution conversion is necessary, step S1104.
In, the print image is divided into blocks. Next, in step S1105, one block of data is taken out, and in step S1106, the ON bits in the block are counted. Then, in step S1107, it is determined whether the ON bit occupies the majority of the bits in the block. If the ON bit does not occupy the majority, that is, if the OFF bit is the majority, the step S1108 is performed as it is.
Then, the thinning process is performed.

In step S1108, bits are thinned out according to a certain rule to reduce the resolution. On the other hand, if the number of ON bits is a majority in step S1107, the process proceeds to step S1109. In step S1109, the black and white of the block are inverted, and the ON bit and the OFF bit in the block are exchanged. After that, step S111
After performing the thinning process at 0, step S1111
Invert the black and white again and reset the ON / OFF bit. After performing the processing in step S1108 or step S1111, in step S1112, step S
It is determined whether or not the thinning-out processing for all the blocks divided in 1104 is completed. If the thinning-out processing is completed, the processing is ended.
Repeat the process from.

The operation of the entire printing apparatus has been described above.
These processes are realized by the computer system of the formatter control unit 1100.

(Other Embodiments) In the first embodiment, the block table is used to determine the symmetry of the block data. However, the table is not used, and the rotation process is performed only when all the block data are ON or OFF. It is also possible to omit it. Furthermore, in the first embodiment, the example of the image data is described, but the same can be applied to the number of rotations of the font. In this case, it is possible to set a flag for a point-symmetrical font in advance and not detect a pattern for the flagged font from the second time and automatically omit the rotation processing.

Further, in the second embodiment, as a method of pattern detection, comparison is made line by line from the end of the block. However, if pattern in the block can be compared, it can be realized by using other pattern matching methods. Needless to say.

Further, in the third embodiment, the thinning process is performed after dividing into blocks in advance. However, if it is not necessary to divide into blocks due to the configuration of the printing apparatus, the dividing process may be omitted.

[0062]

As described above, according to the present invention,
In the image data, a high-speed image can be drawn by performing drawing without performing the rotation process on a portion having symmetry such that the image before rotation is the same as the image after rotation.

Further, after the image data is divided and rotated, the rotated block data is saved / restored in the temporary storage means to speed up the image drawing when the rotation of the same pattern is used a plurality of times. It becomes possible.

Further, by bit-reversing the block data, it is possible to perform optimal thinning-out processing even on an image that is black-and-white inverted by one thinning-out algorithm, and high-quality printing that suppresses quality deterioration even when resolution is lowered. Is possible.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a structure of a laser beam printer according to each embodiment of the present invention.

FIG. 2 is a block diagram showing a basic configuration of a printing apparatus according to the first embodiment.

FIG. 3 is a flowchart illustrating a print control procedure according to the first exemplary embodiment.

FIG. 4 is a flowchart showing a procedure of the drawing process shown in FIG.

5 is a flowchart showing a procedure of a rotation process shown in FIG.

FIG. 6 illustrates an example of a block table according to the first exemplary embodiment.

FIG. 7 is a block diagram illustrating a basic configuration of a printing apparatus according to a second embodiment.

FIG. 8 is a flow chart showing a procedure of the rotation processing shown in FIG. 4 according to the second embodiment.

FIG. 9 is a block diagram showing a basic configuration of a printing apparatus according to a third embodiment.

FIG. 10 is a flowchart showing a procedure of the drawing process shown in FIG. 3 according to the third embodiment.

11 is a flowchart showing a procedure of resolution conversion processing shown in FIG.

[Explanation of symbols]

 1000 printer 1002 laser driver 1003 semiconductor laser 1004 laser beam 1005 rotating polygon mirror 1006 electrostatic drum 1007 developing unit 1008 paper cassette 1009 paper feed roller 1010 transport roller 1011 transport roller 1012 operation panel 1100 formatter control unit 1101 receive buffer 1102 command discrimination unit 1103 Command analysis unit 1104 Command execution unit 1105 Page memory 1106 Data division unit 1107 Rotation execution unit 1108 Cache memory 1109A Pattern detection unit 1109B Thinning detection unit 1109C Inversion execution unit 1200 Interface 1300 Output control unit 1400 Printer engine unit 2000 Host computer

Claims (4)

[Claims] 1. A dividing unit for dividing the received image data into blocks of a predetermined size, and a pattern of the block data divided by the dividing unit is detected to determine whether the pattern is the same as the rotated pattern. A printing apparatus comprising: a determination unit for determining and a rotation unit for rotating the divided block data only when the determination unit determines that the patterns are not the same. 2. The rotating means according to claim 1, wherein the determining means comprises a block data table that is the same before and after the rotation, and compares the divided block data with the block data table. A printing apparatus, which determines whether or not block data before and after rotation is the same. 3. Dividing means for dividing the received image data into blocks of a predetermined size, rotating means for rotating the divided block data, and block data before and after rotation by the rotating means. When the temporary storage means for storing, the new divided block data and the block data already stored in the temporary storage means match, as the block data after rotation for the new divided block data, A printing apparatus comprising: means for retrieving block data already stored in the temporary storage means. 4. A storage means for storing a print image to be supplied to an engine part, a dividing means for dividing the print image into blocks of a predetermined size at the time of the storage, and the divided block data in a predetermined pattern. A printing apparatus comprising: a thinning means for thinning based on the thinning means, and a means for inverting the bits of the block data before and after the thinning processing by the thinning means.