JP3570316B2 - Image data conversion method and apparatus - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image data conversion apparatus, the internal serial printer that prints in particular a plurality of pixels at the same time, an image data conversion device of a serial printer for converting raster format image data into column format image data suitable for a serial printer (a raster column conversion) .
[0002]
[Prior art]
The prior art of such an image data conversion apparatus is disclosed in, for example, "Serial Printer" in JP-A-5-104784 and "Printer Driver for Color Printer and Printing System Using It" in JP-A-11-123861. Have been. These prior arts disclose a serial printer having a function of converting raster format image data into column format image data. When raster format image data is converted into raster columns and one pass worth of column format image data is written to the storage device, printing is started. Since printing is started after converting all the raster format image data for one pass into column format image data, the same column format image data capacity as the raster format image data capacity for one pass is required. Also, printing cannot be started unless raster column conversion for one pass is completed.
[0003]
[Problems to be solved by the invention]
The prior art as described above has several problems as follows. First, in raster column conversion of a serial printer, the storage capacity of column format image data is required to be the same as the storage capacity of raster format image data. The reason is that printing is started after performing raster column conversion for one pass.
[0004]
Second, the start of printing is delayed. The reason is that printing is started after performing raster column conversion for one pass.
[0005]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image data conversion device which enables raster column conversion of an inexpensive serial printer by reducing the storage capacity for storing column format image data in a serial printer. That is.
[0006]
[Means for Solving the Problems]
The present invention is an image data conversion device for performing raster column conversion for converting raster format image data into column format image data and printing with a print head of a serial printer. A data conversion unit that performs a unit smaller than one pass of the print head and is smaller than the number of lines of the print head , and a column storage unit that stores image data in a column format converted by the data conversion unit. It is characterized by having .
[0007]
In a preferred embodiment of the present invention , the control unit includes a control unit and a storage device interconnected by a serial bus. The control unit includes a data conversion unit for performing raster column conversion, and a timing generation for raster column conversion. And a print data generation unit that reads column-format image data from a storage device, converts the data into print data, and outputs the print data.
[0008]
In a preferred embodiment of the present invention, the storage device has a raster data storage unit and a column data storage unit for storing image data in raster format and column format, respectively. The timing generator outputs a change signal generated at the data conversion timing and a print signal generated at the print timing to the data converter and the print data generator, respectively. The system bus has a 16-bit width, and alternately reads raster image data and writes column image data according to a change signal, and reads column image data according to a print signal. Further, the print data generation unit reads the column-format image data from the storage device and converts the image data into print data by parallel-serial conversion or the like.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the configuration and operation of a preferred embodiment of the image data conversion device according to the present invention will be described in detail with reference to the accompanying drawings.
[0010]
Serial printers include an ink jet type, a thermal transfer type, an impact type, and the like, depending on the printing method. However, all of these printing methods are common in that components called print heads perform printing by forming pixels on a storage medium. A typical print head is configured to be able to simultaneously form tens to hundreds of pixels. The print head is fixed on a component called a carrier, and the carrier on which the print head is mounted is reciprocated on a recording medium by a driving source such as a motor. Printing starts after the carrier starts and reaches a certain speed. On the other hand, when printing ends, the carrier decelerates and eventually stops. The time from the start of the carrier to the complete stop is called one pass. Printing during this time is called printing for one pass. In a serial printer, image data created by a personal computer or the like is transmitted via an interface (I / F). At this time, the transmitted image data is image data generally called “ raster format”. This raster format image data is a data format suitable for printing by a line printer, a page printer, or the like. However, in a serial printer, it is necessary to convert this " raster format" image data into a " column format" which is image data suitable for a serial printer. The conversion from the “raster format” image data to the “column format” image data is referred to as “raster column conversion”.
[0011]
First, FIG. 1 is a block diagram of a preferred embodiment of an image data conversion device according to the present invention. This image data conversion device is composed of two parts, a control unit 10 and a storage device 20. The control unit 10 includes a data conversion unit 13, a timing generation unit 14, and a print data generation unit 15. On the other hand, the storage device 20 has therein a raster data storage unit 26 for storing image data in raster format and a column data storage unit 27 for storing image data in column format. The control unit 10 and the storage unit 20 are interconnected by a system bus 30, and are configured to mutually transmit and receive data.
[0012]
The data converter 13 is connected to the timing generator 14 and receives a change signal 18 output from the timing generator 14 at the timing of data conversion. The data converter 13 is connected to a storage device 20 in which raster format image data and column format image data are stored via a 16-bit data bus called a system bus 30. The print data generator 15 is connected to the timing generator 14 and receives a print signal 19 output from the timing generator 14 at the timing of printing. The print data generation unit 15 is connected via a system bus 30 to a storage device 20 in which column format image data is stored.
[0013]
Next, the operation of the image data conversion device according to the present invention will be described with reference to FIGS. FIG. 2 is a flowchart showing the operation of the image data conversion device shown in FIG. FIG. 3 is a timing chart for explaining the operation of the image data conversion device shown in FIG. First, the data generation timing change signal 18 is output from the timing generator 14 (step 101). When detecting the change signal 18, the data conversion unit 13 reads a part of the raster image data from the raster data storage unit 26 (Step 102). The read raster image data is subjected to raster column conversion by the data conversion unit 13 and written to the column data storage unit 27 (step 103).
[0014]
Next, the first print timing print signal 19 is output from the timing generator 14 (step 104). Upon detecting the print signal 19, the print data generation unit 15 reads out the column-format image data from the column data storage unit 27 (step 105), outputs the print data after parallel-serial conversion (step 106). Next, a second print timing print signal 19 is output from the timing generator 14 (step 104). The print data generation unit 15 adds the address to be output to the column data storage unit 27, and reads out image data in the second print column format (step 105). Then, after serial-parallel conversion, the data is output as print data (step 106). Similarly, the print data generation unit 15 reads out the column-format image data until the 16th print signal 19 is output, converts the read image data into print data, and outputs the print data. When the 16th print data output is completed, all the raster-column converted column-format image data has been read (step 107 → step 108).
[0015]
When the 16th print data output is completed, the change signal 18 is output from the timing generator 14 (step 101). When detecting the change signal 18, the data conversion unit 13 reads a part of the raster format image data from the raster data storage unit 26 as in the first case (step 102), but the read address is updated. The read image data in the raster format is subjected to raster column conversion by the data conversion unit 13 and written to the column data storage unit 27 (step 103). However, with respect to the write address, writing is started again from the same address as the first. The series of operations described above is repeated until printing for one pass is completed.
[0016]
Next, access to the storage device 20 of the data conversion unit 13 during raster column conversion (steps 101 to 103) will be described with reference to FIG. 4 which shows a part of the timing chart of FIG. 3 in detail. Here, as an example, a case in which a serial printer has one print head capable of simultaneously printing 32 pixels will be described. Further, as described above, the bit width of the system bus 30 is 16 bits. When the change signal 18 is output from the timing generator 14, the data converter 13 reads 16 words of raster format image data from the raster data storage 26 (see Rr123 in FIG. 4). The read raster-format image data includes 1 word of pixels 1 to 16 of the first raster, 1 word of pixels 1 to 16 of the first raster,..., 1 word of pixels 1 to 16 of the 15th raster, and so on. This is a total of 16 words, that is, 1 word of pixels 1 to 16 of the 16th raster.
[0017]
Next, the read raster-format image data is raster-column-converted by the data conversion unit 13 and the column-format image data is written 16 words into the column data storage unit 27 (see Cw 124 in FIG. 4). The written column-format image data includes 1 word of pixel 1 of the 1st raster to the 16th raster, 1 word of pixel 2 of the 1st raster to the 16th raster,..., Pixel 15 of the 1st raster to the 16th raster. One word is one word of the pixel 16 of the first raster to the sixteenth raster, which is a total of 16 words. Next, the data conversion unit 13 reads 16-word raster image data from the raster data storage unit 26 (see Rr125 in FIG. 4). The read raster-format image data includes 1 word from pixel 1 to pixel 16 on the 17th raster, 1 word from pixel 1 to pixel 16 on the 18th raster,..., 1 word from pixel 1 to pixel 16 on the 31st raster. The total is 16 words, which is 1 word of pixels 1 to 16 of the 32nd raster.
[0018]
Next, the read image data in the raster format is raster column-converted by the data conversion unit 13, and the column-format image data is written 16 words into the column data storage unit 27 (see Cw126 in FIG. 4). The written column-format image data includes 1 word of pixel 1 of the 17th to 32nd rasters, 1 word of pixel 2 of the 17th to 32nd rasters,..., Pixel 15 of the 17th to 32nd rasters. 1 word, ie, 1 word of the pixel 16 of the 17th raster to the 32nd raster, which is a total of 16 words. As a result, the column data storage unit 27 converts the image data of 32 vertical pixels (32 rasters) and 16 horizontal pixels into raster columns and stores them. Next, the first print signal 19 is output from the timing generator. The print data generation unit 15 uses the first print signal 19 as a trigger (trigger) to generate a 2-word (32-bit) column format for printing by the print head at one time from the column data storage unit 27 of the storage device 20. The image data is read (see Cr 122 in FIGS. 3 and 4).
[0019]
The read columnar image data has a total of 2 words, that is, 1 word of pixel 1 of the 1st to 16th rasters and 1 word of pixel 1 of the 17th to 32nd rasters. The print data generation unit 15 converts the 2-word column-format image data into parallel-serial data and outputs the data. The print head performs one print (pixel 1 vertically for 32 pixels) based on the 2-word image data. Hereinafter, from the second time to the 16th time, the same operation is repeated by using the print signal 19 generated from the timing generator 14 as a trigger. As shown in FIG. 4, the reading (Rr) 123 and 125 of the image data in the raster format and the writing (Cw) 124 and 126 of the image data in the column format performed in response to the change signal are collectively shown in FIG. The conversion is indicated by reference numeral 121.
[0020]
Next, the raster format image data in the raster data storage unit 26, the column format image data content in the column data storage unit 27, and the raster column conversion in the data conversion unit 13 will be described in detail. As described above, the system bus 30 prints 32 pixels vertically and 64 pixels horizontally on the A4 size paper 11 shown in FIG. 5 assuming that the system bus 30 is 16 bits wide and the print head can simultaneously print 32 pixels. The case will be described.
[0021]
FIG. 6 is a diagram showing the relationship between the print result 12 shown in FIG. 5 and the storage address of the raster image data in the raster data storage unit 26. The image data of pixels 1 to 16 of the first raster is at address 0h, the image data of pixels 17 to 32 of the first raster is at address 2h, and the image data of the first raster is at 4 words from address 0h to 6h. Is stored. As the image data of the second raster, image data of 32 rasters is stored in 128 words as in the address 8h to Ch.
[0022]
FIG. 7 also illustrates the same contents as FIG. FIG. 8 is a diagram showing the relationship between the column format image data in the column data storage unit 27 and the storage address after raster column conversion by the first change signal 18 when obtaining the print result 12 shown in FIG. It is. The image data of the pixel 1 of the first raster to the 16th raster is address 100h, the image data of the pixel 1 of the 17th to 32nd raster is address 102h, the image data of the first raster to the 16th raster is address 104h, As the image data of the pixel 2 of the 17th to 32nd rasters, 32 words of image data of the raster from the pixel 1 to the pixel 16 are stored as in the address 106h. It can be seen that the image data in the column format is 32 words, which is a quarter, which is smaller than 128 words in the raster format.
[0023]
FIG. 9 is a diagram showing the contents in the middle of writing to the column data storage unit 27. This is the contents of the column data storage unit 27 immediately after writing 1 word within 16 words of writing to the column data storage unit 27 in FIG. 4 (see 126 in FIG. 4). FIG. 10 is a diagram showing the relationship between the column format image data in the column data storage unit 27 and the storage addresses after raster column conversion by the second change signal 18. Although the address of the column data storage unit 27 has not changed, it can be seen that the stored contents are different. FIG. 11 and FIG. 12 are views showing a state of raster column conversion in the data conversion unit 13. Read data 1 to 16 in FIG. 11 correspond to 123 in FIG. 4, and write data 1 to 16 correspond to 124 in FIG. Read data 1 to 16 in FIG. 12 correspond to 125 in FIG. 4, and write data 1 to 16 correspond to 126 in FIG.
[0024]
As described above, in the image data conversion device according to the present invention, the data conversion unit 13 uses the data conversion timing change signal 18 output from the timing generation unit 14 as a trigger to store the raster-format image data from the raster data storage unit 26 of the storage device 20. Read data. The read image data in raster format is subjected to raster column conversion by the data conversion unit 13. The converted column-format image data is written to the column data storage unit 27 of the storage device 20. At this time, the amount of image data subjected to the raster column conversion is not all image data for one pass but image data of several words. Next, using the print timing print signal 19 output from the timing generator 14 as a trigger, the print data generator 15 reads one column of image data from the storage device 20 and converts it into print data (for example, parallel serial data). Conversion) and output. Since the print timing print signal 19 is sequentially output from the timing generation unit 14, the process is repeated until all of the raster-column-converted column-format image data is read. When all the image data in the column format subjected to the raster column conversion is read, a data conversion timing change signal 18 is output from the timing generation unit 14, and the data conversion unit 13 performs the raster column conversion. Hereinafter, the process is repeated until printing for one pass is completed.
[0025]
The configuration and operation of the preferred embodiment of the image data conversion device according to the present invention have been described above in detail. However, it should be noted that such exemplary embodiments are merely examples of the present invention and do not limit the present invention in any way. It will be readily apparent to those skilled in the art that various modifications can be made without departing from the spirit of the invention.
[0026]
【The invention's effect】
As is clear from the above description, the following remarkable effects can be obtained by the image data conversion device of the present invention. First, the amount of image data in the column format can be made smaller than the amount of image data in the raster format. In the embodiment, the raster format image data is 128 words, and the column format image data is 32 words, which is a quarter. If printing is performed on the entire surface of an A4-size sheet at a resolution of 600 dpi, the width is about 4,800 pixels, and the image data in the raster format is 9,600 words. There is no increase in the image data in the column format, and it is 32 words, which is 1/300. The reason for this is to reduce the amount of column-format image data by sequentially performing raster column conversion during printing without performing raster column conversion for one pass before starting printing.
[0027]
Second, the start of printing can be expedited. The reason is that since the raster column conversion is not performed before printing, printing is started earlier by that much.
[Brief description of the drawings]
FIG. 1 is a block diagram of a preferred embodiment of an image data conversion device according to the present invention.
FIG. 2 is a flowchart illustrating an operation of the image data conversion device of FIG. 1;
FIG. 3 is a timing chart showing an operation of the image data conversion device of FIG. 1;
FIG. 4 is a timing chart showing a part of FIG. 3 in detail.
FIG. 5 is a diagram illustrating an example of a print result printed by a serial printer.
FIG. 6 is a diagram illustrating a relationship between a raster format image data address and a print result.
FIG. 7 is a diagram illustrating a relationship between raster image data addresses and print results.
FIG. 8 is a diagram illustrating a relationship between an image data address in a column format and a print result.
9 is a diagram showing contents in the middle of writing to a column data storage unit in the image data conversion device in FIG. 1;
FIG. 10 is a diagram illustrating a relationship between image data addresses in column format and print results.
FIG. 11 is an explanatory diagram of raster column conversion in a data conversion unit in the image data conversion device shown in FIG. 1;
FIG. 12 is an explanatory diagram of raster column conversion in a data conversion unit in the image data conversion device shown in FIG. 1;
[Explanation of symbols]
Reference Signs List 10 Control unit 13 Data conversion unit 14 Timing generation unit 15 Print data generation unit 18 Change signal 19 Print signal 20 Storage device 26 Raster data storage unit 27 Column data storage unit 30 System bus

Claims (6)

In an image data conversion apparatus for performing raster column conversion for converting raster format image data into column format image data and printing with a print head of a serial printer, one time of the raster column conversion, one of the print heads is used. A data conversion unit that performs the conversion in units smaller than the pass and in units smaller than the number of lines of the print head; and a column data storage unit that stores the image data in the column format converted by the data conversion unit. Image data conversion device. The system bus is composed of interconnected control unit and a storage device, said storage device comprises the column data storage unit, wherein, before and Kide over data conversion unit, the raster column conversion timing generator 2. A timing generation unit for controlling the image data, and a print data generation unit for reading out column-format image data from the column data storage unit of the storage device, converting the read image data into print data, and outputting the print data. Image data conversion device. It said storage device, the image data converting apparatus according to claim 2, characterized in that it comprises a raster data storage unit for storing image data before Symbol raster format. The said timing generation part outputs the change signal which generate | occur | produces at the timing of the said data conversion, and the print signal which generate | occur | produces at the print timing to the said data conversion part and the print data generation part, respectively. Image data conversion device. The system bus is 16 bits wide, and alternately reads raster image data and writes column image data in response to the change signal, and reads column image data in response to the print signal. The image data conversion device according to claim 4, wherein the conversion is performed. The print data generation unit reads the image data of the column format from the storage device, the image data conversion according to any one of claims 2 to 5, characterized in that it is converted to a print data to the parallel-serial conversion apparatus.

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