JPH1016275A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a printing where the number of pixels being recorded through main scanning is doubled as compared with an ordinary case without increasing the printer cost significantly or increasing the burden on an image signal source. SOLUTION: First and second line memory means 11, 12 for storing a line of input image data to a printer 15 are provided and an operating means 13 produces an image data required for doubling the density in the subscanning direction based on the image data stored in respective line memory means 11, 12. High density recording in subscanning direction is realized by inserting the image data produced from the operating means in the subscanning direction of the input image data to the printer. The line memory means 11, 12 are used as one continuous memory means for storing an image data where the number of pixels per line is doubled as compared with an ordinary case thus realize a printing where the number of pixels being recorded through main scanning is doubled as compared with an ordinary case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data processing system for increasing the recording density in the sub-scanning compared to the main scanning in a thermal printer, and realizes printing with twice the number of recording pixels in the main scanning by using this method. The data processing method when performing the operation.

[0002]

2. Description of the Related Art In a conventional printer, for example, in order to realize printing in which the recording density in the sub-scanning is twice as high as that in the main scanning (hereinafter referred to as "sub-scanning double density printing"), the recording densities in the main scanning and the sub-scanning are required. Has to input twice as much image data to the printer as compared to the same printing (hereinafter referred to as normal printing). For this reason, an image signal source (for example, a personal computer), which is a sender of image data, requires twice as much image data storage capacity as during normal printing, and needs to perform twice as much data processing as during normal printing. Therefore, in order to comfortably perform sub-scanning double density printing, the image signal source had to have a certain high processing capability. For example, as shown in FIG. 7 of Japanese Patent Publication No. 7-87519, a video signal memory, a counter, a gradation counter, a comparator to which the memory output and the gradation counter output are input, a shift register, a latch circuit, and the like. In order to perform sub-scanning double-density printing using a printer including a head drive circuit and a heating head, it was necessary to process twice as much image data as an ordinary signal for an image signal source. Therefore, the image signal source is instructed to print compared to normal printing, and until printing ends.
In other words, it took a very long time to be released to the printer.

[0003]

SUMMARY OF THE INVENTION The present invention reduces the burden on the image signal source without significantly increasing the cost of the printer, and provides high-quality printing with a high recording density in the sub-scanning direction compared to the main scanning. It is an object of the present invention to provide a thermal printer that employs an image data processing method for realizing printing in which the number of recording pixels for main scanning is twice the normal number.

[0004]

According to the present invention, a first line storage means and a second line storage means for storing one line of image data of image data inputted to a printer are provided. Means for generating the image data necessary for the double density in the sub-scanning direction based on the image data stored in the means and the second line storage means, and in the sub-scanning direction of the image data input to the printer, By inserting the generated image data, high-density sub-scan printing is realized. Further, by regarding the first line storage unit and the second line storage unit as one continuous storage unit, the number of pixels in one line is twice as large as that of normal image data, and the number of recording pixels in the main scan is normal. Achieve double printing.

[0005]

FIG. 1 shows the configuration of a printer provided with data processing means according to the present invention. The printer including the data processing unit according to the present invention includes a first line storage unit 11, a second line storage unit 12,
, A selection unit 14, a printing unit 15, and a system control unit 16.

[0006] The first line storage means 11 stores one line of image data in the main scanning direction which is input to the printer. The first line storage means 11 can be realized by, for example, a static memory. Second line storage means 12
Stores image data of one line in the main scanning direction which is input to the printer in the same manner as the first line storage unit 11.

The calculating means 13 comprises a first line storing means 11
Then, arithmetic processing is performed based on the image data input from the second line storage means 12 to generate arithmetic data. The calculation means 13 can be realized by, for example, an adder, a multiplier, a DSP, or the like.

[0008] The selection means 14 is a first line storage means 1
1. Select and output any one of the image data input from the second line storage means 12 and the calculation means 13. This selecting means 14 can be realized by, for example, a general-purpose IC multiplexer.

The printing means 15 prints on photographic paper based on the image data for one line in the main scanning direction input via the selection means 14. It corresponds to a thermal head and its control means in a thermal transfer printer, and adjusts the energizing time of each heating element of the thermal head according to the gradation value of each dot of input image data.

The system control means 16 includes a procedure for receiving image data with an image signal source (not shown), control of reading and writing of image data from and to the first line storage means 11 and the second line storage means 12, and a selection means 14. , And instructs the printing means 15 to print. The system control means can be realized by, for example, a microcomputer.

FIG. 2 shows an example of image data input to the printer 15. In this example, the size of the image data is 6 dots vertically and 8 dots horizontally. Each line is composed of 6 dots, and the alphabet shown in each dot indicates the line, and each dot can be identified for explanation. Each dot has a unique tone value. For example, if the number of bits per dot is eight, one dot can express 256 levels of tone. A line A31 is a line to be printed (main scanning) first, and hereinafter, a line B32, a line C33,.
.. Are input in the order of line H38. In some cases, the same line may be input twice.

FIG. 3 shows an example of image data used when printing is performed in which the recording density of the sub-scan is twice that of the main scan. Lines A31 to H are image data input to the printer shown in FIG. The lines a41 to 47 are generated by arithmetic processing based on the lines A31 to H38. Line a41 is based on lines A31 and 32, and line 42 is based on line 32.
Each line is generated by arithmetic processing based on the lines on both sides, and so on.
Lines a41 to f47 are each composed of six dots, as in the case of lines A31 to H. The alphabet shown in each dot indicates the line, so that each dot can be identified for explanation. Each dot has a unique gradation value. For example, let the dot for which the arithmetic processing is generated be the average value of the tone values of the adjacent dots on both sides, the tone value of the dot A1 on the line A31 be 128,
Assuming that the tone value of the dot B1 of the line B32 is 64, the tone value of the dot a1 of the line a41 is 96 which is the average value of both dots.

The operation of the printer according to the present invention shown in FIG. 1 in the sub-scanning double-density printing in which the sub-scanning recording density is twice that of the main scanning will be described with reference to FIGS. 2 and 3. FIG. It is assumed that image data to be input to the printer is input in units of lines, and that the order of inputting lines is determined in advance by an image signal source (not shown) which is a sender of image data.

(1) An image signal source (not shown) requests printing to the system control means 16. (2) The system control means 16 controls the selection means 14 to select the input from the first line storage means 11. Thereafter, input of image data to the image signal source is permitted, and write control is performed on the first line storage unit 11 to write the line A31 into the first line storage unit 11. When the writing of the line A31 to the first line storage means 11 is completed, the input of image data to the image signal source is prohibited.

(3) The system control means 16 performs read control on the first line storage means 11. As a result, the printing unit 15 stores the dots A1,
The line A31 read in the order of the dots A2,..., Dot A6 is input via the selection means 14.
After finishing reading the line A31 stored in the first line storage unit 11, the system control unit 16 instructs the printing unit 15 to print the input line A31. (4) The printing unit 15 prints on photographic paper based on the input image data of the line A31.

(5) The system control means 16 controls the line A
When the printing of the image data of 31 is completed, the selection unit 14 is controlled to select the input from the calculation unit 13.
After that, the input of the line B32 is permitted to the image signal source, and the writing control is performed on the second line storage unit 12 to write the line B32 into the second line storage unit 12. When the writing of the line B32 is completed, the input of the image data to the image signal source is prohibited. (6) The system control means 16 stores the first line storage means 1
Read control is performed on the first and second line storage means 12. Dot A1, dot A from the first line storage means 11
The line A31 is read in the order of 2,..., Dot A6, and at the same time, the line B32 is read from the second line storage means 12 in the order of the dots B1, dot B2,. As a result, image data up to the pair of the dot A6 and the dot B6 is sequentially input to the arithmetic unit 13 such that the dot A1 and the dot B1 are paired, and the dot A2 and the dot B2 are paired. As a result, a1 to a6 of the line a41 are generated, and the generated line a41 is input to the printing unit 15. After finishing reading the line a41 stored in the first line storage unit 11 and the second line storage unit 12, the system control unit 16 instructs the printing unit 15 to print the input line a41. (7) The printing means 16 prints on photographic paper based on the image data of the line a41 input from the selecting means 14.

(8) The system control means 16 sets the line a
When the printing of the image data of 41 is completed, the selection unit 14 is controlled to select the input from the second line storage unit 12. Thereafter, read control is performed on the second line storage unit 12. Thus, the line B32 read from the second line storage unit 12 in the order of dot B1, dot B2,..., Dot B6 is input to the printing unit 15 via the selection unit 14. The system control means 16
Line B32 stored in the second line storage means 12
Is completed, the printing unit 15 is instructed to print the input line B32. (9) The printing unit 15 prints on photographic paper based on the input image data of the line B32.

(10) When the printing of the image data of the line B32 is completed, the system control means 16
Is controlled to select the input from the arithmetic means. Thereafter, the input of the line C33 is permitted to the image signal source, and the writing control is performed on the first line storage unit 11 to write the line C33 into the first line storage unit 11. When the writing of the line C33 is completed, the input of image data to the image signal source is prohibited. (11) The system control means 16 performs read control on the first line storage means 11 and the second line storage means 12. Dot C1, dot C from the first line storage means 11
The line C33 is read out in the order of 2,..., Dot C6, and at the same time, the line B32 is read out of the second line storage means 12 in the order of dot B1, dot B2,. As a result, the dot B1 and the dot C1 are paired, and the dot B2 and the dot C2 are paired with the dot B2 and the dot C2.
Up to six pairs of image data are sequentially input. As a result,
The lines b1 to b6 of the line 42 are generated, and the line 42 is input to the printing unit 15. When the reading of the line 42 stored in the first line storage unit 11 and the second line storage unit 12 is completed, the system control unit 16 instructs the printing unit 15 to print the input line 42. (12) The printing unit 16 prints on photographic paper based on the image data of the line 42 input from the selection unit 14.

(13) When the printing of the image data of the line 42 is completed, the system control means 16 controls the selection means 14 to select the input from the first line storage means 11. Thereafter, read control is performed on the first line storage means 11. Thus, the line C33 read from the first line storage unit 11 in the order of the dots C1, C2,..., Dot C6 is input to the printing unit 15 via the selection unit 14. System control means 16
Is the line C stored in the first line storage means 11
When the reading of the line 33 is completed, the printing unit 15 is instructed to print the input line C33. (14) The printing unit 15 prints on photographic paper based on the input image data of the line C33. (15) The printing of the lines A31, a41, B32, b42, and C33 has been completed.

Thereafter, similarly, image data from line D34 to line H38 is inputted, and lines c43, D34, d44,..., Line E37, line e47, and line F38 are printed. In addition, it is possible to realize printing in which the recording density of the sub-scanning is twice that of the main scanning.

In the above embodiment, the calculation of the line data to be interpolated was obtained by averaging the values of the same place of the previous line and the following line, but interpolation from appropriate pixels becomes possible.
A method of detecting a contour of an image and generating a new pixel from a pixel on the contour line, and a method of selecting an interpolation method by detecting a direction of change in shading of a pixel, which is an interpolation method in consideration of heat storage of a thermal head. For example, an interpolation method can be appropriately selected and used. In the former interpolation method, for dot b2, A1 of line A + B3 of line B, A2 of line A + B2 of line B, A3 of line A + B of line B
By calculating the data of 1 and selecting the largest value, data of the pixel on the contour line can be generated.
In the latter interpolation method, A1> B1 for dot b1
A1 × １ ／ + B1 × 3 when changing from light to dark when
/ 4, when A1 <B1 changes from dark to light A1 ×
3/4 + B1 × １ ／, when A1 = B1, a dot b suitable as (A1 + B1) / 2 when there is no change from dark to dark
A value of 1 can be obtained.

As described above, by inputting exactly the same amount of image data to the printer 15 as in the normal printing in which the recording densities of the main scanning and the sub-scanning are equal according to the present embodiment, the sub-scanning recording with respect to the scanning is performed. Double density printing can be realized.

In this embodiment, the input image data is written only in the first line storage means 11,
The selection means 14 always selects the input from the first line storage means 11, or the input image data is written only to the second line storage means 12, and the selection means 14 Line storage means 12
If it is configured to always select the input from the printer, it is possible to print only the image data input to the printer.

The first line storage unit 11 and the second line storage unit 12 are used as one storage unit, and the input from the first line storage unit 11 and the input from the second line storage unit 12 are performed by the selection unit 14. If the input is selected, it is possible to cope with printing in which the total number of images in one line is twice as large as usual.

In this embodiment, the image data necessary for printing each line is held in the first line storing means and the second line storing means until the printing of each line is completed. Therefore, in the description of the present embodiment, the image data is input to the printing unit once for each line printing, but the same image data can be input to the printing unit a plurality of times. .

[0026]

FIG. 4 is a block diagram showing the configuration of a printer having data processing means according to a second embodiment of the present invention. The printer of this embodiment has a first line storage unit 1
1, the second line storage unit 12, the calculation unit 13, the printing unit 15, the system control unit 16, the first selection unit 1,
7 and second selecting means 18.

The first line storage means 11 stores one line of image data in the main scanning direction (hereinafter, referred to as original image data) input to the printer. First line storage means 1
1 can be realized by, for example, a static memory. The second line storage unit 12 stores the image data input from the first selection unit 11. Second line storage means 12
Can be realized by, for example, a static memory. The calculation means 13 performs calculation processing based on the original image data and the image data input from the first line storage means 11 to generate new image data (hereinafter referred to as calculation data).
The calculation means can be realized by, for example, an adder, a multiplier, a DSP, or the like. The printing means 15 prints on photographic paper based on image data for one line in the main scanning direction input via the second selecting means 18. It corresponds to a thermal head and its control means in a thermal transfer printer, and adjusts the energizing time of each heating element of the thermal head according to the gradation value of each dot of input image data. The system control means 16 includes a procedure relating to image data reception with an image signal source (not shown), control of reading and writing of image data with respect to the first line storage means 11 and the second line storage means 12, the first selection means 17 and The selection of the second selecting unit 18 is controlled, and the printing unit 18 is instructed to print. The system control means 16 can be realized by a microcomputer, for example.

The first selecting means 17 selects and outputs one of the original image data and the operation data from the operation means 13. The first selecting means 17 can be realized by, for example, a general-purpose IC multiplexer. The second selection unit 18 selects and outputs one of the image data stored in the first line storage unit 11 and the image data stored in the second line storage unit 12. The second selecting means 18 is, for example, a general-purpose IC
Can be realized by the multiplexer of FIG.

The operation of the printer according to the present invention shown in FIG. 4 during sub-scanning double-density printing in which the sub-scanning recording density is twice that of the main scanning will be described with reference to FIGS. Note that the first selection means 17 is provided by the calculation means 13 from the start of printing to the end of printing.
Control to select input from. (1) The image signal source not shown is the system control unit 1
6 is requested to print. (2) The system control means 16 controls the first selection means 17 to select an input from the calculation means 13 and controls the second selection means 18 to select an input from the first line storage means 11. . Thereafter, the input of the line A31 is permitted to the image signal source, and the first line storage unit 1 is input.
1 is written, and the line A31 is written in the first line storage unit 11. When the writing of the line A31 to the first line storage unit 11 is completed, the system control unit 16 prohibits the input of image data to the image signal source. (3) The system control means 16 stores the first line storage means 1
1 is read-out controlled. As a result, the printing unit 15 stores the dot A1, the dot A2,.
The line A31 read in the order of the dot A6 is input to the printing unit 15 via the second selecting unit 18. The system control means 16 stores the first line storage means 11
When the reading of the line A31 stored in is completed, the printing unit 15 is instructed to print the input line A31. (4) The printing unit 15 prints on photographic paper based on the input image data of the line A31.

(5) The system control means 16 controls the line A
When the printing of the image data of No. 31 is completed, the second selecting means 1
8 is controlled to select the image data from the second storage unit 12. Thereafter, the line B32 is applied to the image signal source.
At the same time, the read control is performed on the first line storage means 11 and the write control is performed on the second line storage means 12. The reading of the image data from the first line storage means at this time is performed in the order of dot A1, dot A2, dot A3,..., Dot A6 in synchronization with the input line B32. As a result, the line A31 stored in the first line storage means 11 has one input of the arithmetic means 13 as the dot A1, the dot A2, the dot A3,.
., Dot A6 is input in the order, and line B32 is input to dot B1, dot B2, dot B3,
.. Are input in the order of dot B6. As a result, the line a41 generated by the calculation means 13 in the second line storage means 12 is represented by a dot a1, a dot a2, a dot a3,
.. Are input in the order of dot a6. When all the image data of the line a41 is written in the second line storage unit 12, the system control unit 16 prohibits the input of the image data to the image signal source.

(6) The system control means 16 performs read control on the second line storage means 12. The line a41 read from the second line storage unit 12 is a dot a1,
The dots a2,..., And the dot a6 are input to the printing unit 15 via the second selection unit 18 in the order of dot a2. When reading out the line a41 stored in the second line storage unit 12, the system control unit 16 instructs the printing unit 15 to print the input line a41. (7) The printing means 16 prints on photographic paper based on the image data of the line a41 input by the second selection means.

(8) The system control means 16 sets the line a
When the printing of the image data of No. 41 is completed, the second selecting means 1
8 is controlled so as to select the image data from the first line storage means 11. Thereafter, the input of the line B32 is permitted to the image signal source, and the first line storage unit 11
, And writes the line B32 into the first line storage unit 11. When the writing of the line B32 is completed, the input of image data to the image signal source is prohibited.

(9) The system control means 16 performs read control on the first line storage means 11. As a result, the line B32 read from the first line storage unit 11 in the order of the dots B1, dot B2,..., Dot B6 of the line B32 from the first line storage unit 11 is input to the printing unit 15 via the second selection unit 18. You. When the reading of the line B32 stored in the first line storage unit 11 is completed, the system control unit 16 instructs the printing unit 15 to print the input line B32. (10) The printing unit 15 prints on photographic paper based on the input image data of the line B32.

(11) When the printing of the image data of the line B32 is completed, the system control means 16 controls the second selection means 18 to select the image data from the second storage means 12. Thereafter, the line C3 is applied to the image signal source.
At the same time as the input of 3 is permitted, read control is performed on the first line storage means 11 and write control is performed on the second line storage means 12. At this time, the reading of the image data from the first line storage means 11 is performed in synchronization with the input line C33 by the dot B1, the dot B2, and the dot B.
3,..., Dot B6. As a result, the line B32 stored in the first line storage unit 11 is input to one input of the arithmetic unit 13 in the order of dot B1, dot B2, dot B3,..., Dot B6, and the other input. Has line C33 as dot C1, dot C2,
The dots C3,..., Dot C6 are input in this order. As a result, the line b42 generated by the calculation means 13 in the second line storage means 12 is the dot b1, the dot b2,
The dots are input in the order of dots b3,. When all the lines a41 are written in the second line storage means, input of image data to the image signal source is prohibited.

(12) The system control means 16 performs read control on the second line storage means 12. The line b42 read from the second line storage unit 12 is a dot b
.., Dot b6 in the order of the dots b2,. When reading the line b42 stored in the second line storage unit 12, the system control unit 16 instructs the printing unit 15 to print the input line b42. (13) The printing unit 15 prints on photographic paper based on the image data of the line b42 input to the second selection unit 18.

(14) When the printing of the image data of the line b42 is completed, the system control means 16 controls the second selection means 18 to select the image data from the line storage means 11. Then, the line C is applied to the image signal source.
33 and the first line storage means 11
, And writes the line C33 into the first line storage unit 11. When all the lines C33 are written, input of image data to the image signal source is prohibited.

(15) The system control means 16 performs read control on the first line storage means 11. This allows
The second selection unit 18 inputs the line C33 read from the first line storage unit 11 in the order of the dots C1, the dots C2,... After finishing reading the line C33 stored in the first line storage unit 11, the system control unit 16
5 is instructed to print the input image data. (16) The printing means 15 prints on photographic paper based on the input image data of the line C33.

(17) Up to this point, line A31, line a41, line B32, line b42, line C33
Finished printing of the line. Hereinafter, similarly, the line D
By inputting image data from line 34 to line H38 and printing lines c43, line D34, line d44,..., Line G37, line g47, and line H38, sub-scanning is performed with respect to main scanning. Printing with twice the recording density can be realized.

In this embodiment, the image signal source, which is the sender of the image data, has to input the same line twice. It does not overwhelm the storage area of the signal source. Further, the load on the image signal source does not increase because of the simple processing of inputting the same line twice.

In the above description of the operation of the present embodiment, the input to the printing means 15 is performed once for one line printing. However, the configuration is such that the first line storage means 11 and the second line storage means 12 can hold image data necessary for printing of each line until printing of each line is completed. Therefore, it is possible to input the same image data to the printing means a plurality of times for printing one line. Further, since the operation data is stored in the second line storage unit 12 in advance before the printing of each line is started, it is possible to input the image data to the printing unit 15 at high speed.

In this embodiment, the first selecting means 17
By controlling to select only the original image data in,
Writing of the original image data to the second line storage unit 12 becomes possible. As a result, the first line storage unit 11 and the second line storage unit 12 can be used as one line storage unit, and image data in which the number of pixels in one line is twice the normal number can be stored. Therefore, it is possible to cope with printing in which the number of pixels in the main scan is twice the normal number.

The writing of the original image data is performed only to the first line storage means 11, and the input from the first line storage means 11 is always selected by the second selection means 18, or The writing of the image data is performed only to the second line storage means 12 and the second selection means 18
In this case, if the input from the second line storage means 12 is always selected, it is possible to print only the image data input to the printer.

FIG. 5 is a block diagram showing the configuration of a third embodiment of the printer according to the present invention. The printer of this embodiment includes a line storage unit 11, a calculation unit 13, a selection unit 14, a printing unit 15, a system control unit 1,
6. Pixel storage means 19. The line storage unit 11 stores image data of one line in the main scanning direction (hereinafter, referred to as original image data) input to the printer 15. The line storage means 11 can be realized by, for example, a static memory. The calculation means 13 performs calculation processing based on the original image data and the image data stored in the pixel storage means 19, and generates new image data (hereinafter, referred to as calculation data). The calculation means 13 can be realized by, for example, an adder, a multiplier, a DSP, or the like. The selecting unit 14 selects one of the original image data and the operation data from the operation unit 13 and inputs it to the line storage unit 11. The selection means can be realized by, for example, a general-purpose IC multiplexer. The printing unit 15 prints on photographic paper based on the image data input from the line storage unit 11. It corresponds to a thermal head and its control means in a thermal transfer printer, and adjusts the energizing time of each heating element of the thermal head according to the gradation value of each dot of input image data. The system control unit 16 controls the reading and writing of image data to and from the procedure line storage unit 11 regarding image data reception with an image signal source (not shown), and the selection unit 1.
4 is selected, and a print instruction is issued to the printing unit 15. The system control means can be realized by, for example, a microcomputer. The pixel storage unit 19 stores one pixel of the image data read from the line storage unit 11. The pixel storage unit 19 can be realized by a flip-flop.

The operation of the printer according to the third embodiment of the present invention shown in FIG. 5 at the time of printing in the sub-scanning double density where the recording density of the sub-scanning is twice that of the main scanning will be described with reference to FIGS. explain. The image data input to the printer is input in units of lines, and the input order of dots in each line is ascending number (for example, if the line is A31, the dots A1 and A
2, dot A3... Dot A6). Also,
It is assumed that the order of inputting the lines is determined in advance by an image signal source (not shown) which is a sender of the image data. (1) The image signal source not shown is the system control unit 1
6 is requested to print. (2) The system control means 16 controls the selection means 14 to select a printer input (hereinafter, referred to as original image data). Thereafter, the line A31 is applied to the image signal source.
Is written into the line storage means 11 at the same time as the input of the data is permitted. As a result, the selection unit 14 is provided to the printing unit 15.
Is input, and the line A31 is stored in the line storage unit 11. After completing the input of the line A31, the system control means 16 prohibits the input of image data to the image signal source. (3) The printing unit 15 prints on photographic paper based on the input image data of the line A31.

(4) The system control means 16 controls the line A
When the printing of the image data 31 is completed, the selection means 14 is controlled to select the input from the calculation means 13. (5) The system control means 16 first reads out the dot A1 from the image data stored from the line storage means 11, and stores the read dot A1 in the pixel storage means 19. Thereafter, the input of the dot B1 of the line B32 is permitted to the image signal source. As a result, the two pixels of the dot A1 and the dot B1 are input to the calculating unit 13,
Pixel a1 is generated. Then, the generated a1 is overwritten on the position of the line storage unit 11 where the dot A1 is stored.

Next, the dot A2 is read out of the image data stored from the line storage means 11, and the read dot A2 is stored in the pixel storage means 19. Thereafter, the input of the dot B2 in the line B32 is permitted to the image signal source. As a result, the dot A2 and the dot B
The pixel a2 is generated because two pixels 2 are input. Then, the generated a2 is overwritten on the position of the line storage unit 11 where the dot A2 is stored. Hereinafter, a line a41 composed of the pixels a1 to a6 is generated by repeating the same operation, and is input to the line storage unit 11. (6) The system control unit 16 instructs the printing unit 15 to print the input line a41. (7) The printing unit 16 selects the line a4 input by the selecting unit.
The printing is performed on photographic paper based on the image data of No. 1.

(8) The system control means 16 sets the line a
When the printing of the image data of 41 is completed, the selection unit 14 is controlled to select the input of the printer 15. Thereafter, input of the line B32 is permitted to the image signal source, and at the same time, writing is performed on the line storage control means 11.
Thus, the line B32 via the selection unit 14 is input to the printing unit 15 and the line B32 is stored in the line storage unit 11. The system control means 16
When the input of the line A31 is completed, the input of the image data to the image signal source is prohibited. (9) The system control unit 16 instructs the printing unit 15 to print the input line B32. (10) The printing unit 15 prints on photographic paper based on the input image data of the line B32.

(11) When the printing of the image data of the line B32 is completed, the system control means 16
Is controlled to select the input from the arithmetic means 13. (12) The system control unit 16 first reads out the dot B1 from the image data stored from the line storage unit 11, and stores the read dot B1 in the pixel storage unit 19. Thereafter, the system control means 16 permits the input of the dot C1 in the line B32 to the image signal source. As a result, the two pixels of the dot B1 and the dot C1 are input to the arithmetic unit 13, and the pixel b1 is generated. Then, the generated b1 is stored in the dot B of the line storage unit 11.
Overwrite the position where 1 is stored.

Next, the dot B2 is read out of the image data stored from the line storage unit 11, and the read dot A2 is stored in the pixel storage unit 19. Thereafter, the input of the dot C2 of the line B32 is permitted to the image signal source. As a result, the dot B2 and the dot C
Since two pixels 2 are input, a pixel b2 is generated. Then, the generated b2 is overwritten on the position of the line storage unit 11 where the dot B2 is stored. Hereinafter, by repeating the same operation, the pixels b1 to b6
Is generated and input to the line storage unit 11. (13) The system control means 16 instructs the printing means 15 to print the input line c42. (14) The printing unit 16 selects the line c input by the selecting unit.
Printing is performed on photographic paper based on the 42 image data.

(15) When the printing of the image data of the line c42 is completed, the system control means 16
To select the input of the printer. Thereafter, the input of the line C33 is permitted to the image signal source, and at the same time, the writing to the line storage control means 11 is performed.
As a result, the line C33 via the selection unit 14 is input to the printing unit 15, and the line C33 is stored in the line storage unit 11. After completing the input of the line C33, the system control means 16 prohibits the input of image data to the image signal source. (16) The system control unit 16 instructs the printing unit 15 to print the input line C33. (17) The printing unit 15 prints on photographic paper based on the input image data of the line C33. (18) The printing of the lines A31, a41, B32, c42, and C33 has been completed. Hereinafter, in the same manner, the main scanning is performed by inputting image data from line D34 to line H38 and printing lines c43, D34, d44,..., Line G37, line g47, and line H38. In contrast, printing with double the recording density in the sub-scanning can be realized.

In the above description of the operation of the present embodiment, one input to the printing means 15 is performed for one line of printing. However, the configuration is such that the line storage means 11 can hold image data necessary for printing of each line until printing of each line is completed. Therefore, 1
It is possible to input the same image data to the printing means a plurality of times for printing a line.

In the present embodiment, the same line must be input twice by the image signal source which is the sender of the image data. It does not overwhelm the storage area of the signal source. Further, the load on the image signal source does not increase because of the simple processing of inputting the same line twice.

In this embodiment, the selecting means 14
In this case, if the image data input to the printer 15 is always selected, it is possible to print only the image data input to the printer.

Further, in this embodiment, since only one line storage means 11 is required, the circuit scale can be reduced, and the cost of parts can be reduced.

The printer shown in FIG. 6 is a fourth embodiment according to the present invention, and is characterized in that a second calculating means 20 and a second selecting means 21 are added to the configuration of the printer shown in FIG. doing. The second calculating means 20 can be realized by, for example, a combination of a flip-flop and a multiplier or a DSP, and the selecting means 21 can be realized by a general-purpose IC multiplexer. In FIG. 6, first line storage means 1
1 and the input of the second line storage means 12 to the second selection means 21
, The same operation as that of the printer shown in FIG. 1 can be performed. Further, if the input of the first line storage means 11 and the second line storage means 12 is made the output of the second calculation means 20 by the second selection means 21, the printing of the image data subjected to the calculation processing in the main scanning direction can be performed. Can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a printer according to a first embodiment for realizing double-scanning double-density printing according to the present invention.

FIG. 2 is a diagram showing an example of image data input to a printer according to the present invention.

FIG. 3 is a view showing an example of image data generated by a printer according to the present invention.

FIG. 4 is a block diagram showing the configuration of a printer according to a second embodiment for realizing double-scanning double-density printing according to the present invention.

FIG. 5 is a block diagram showing a configuration of a printer according to a third embodiment for realizing double-scanning double-density printing according to the present invention.

FIG. 6 is a block diagram showing a configuration of a printer according to a fourth embodiment in which a calculation unit in the main scanning direction is added to the printer shown in FIG. 1 according to the present invention.

[Explanation of symbols]

 Reference Signs List 11 first line storage means 12 second line storage means 13 calculation means 14 selection means 15 printing means 16 system control means 17 first selection means 18 second selection means 19 pixel storage means 20 second calculation means 21 second selection means

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takashi Omata 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the multimedia system development headquarters of Hitachi, Ltd. (72) Inventor Hideaki Ito Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa 292 Hitachi Image Information Systems, Ltd. Address: Hitachi, Ltd. Multimedia Systems Development Division (72) Inventor: Koji Kawakami 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture

Claims (7)

[Claims] 1. A first line storage unit and a second line storage unit for storing one line of input image data (hereinafter, referred to as original image data), and the first line storage unit and the second line storage unit. A calculating means for generating new image data (hereinafter referred to as calculation data) based on the image data respectively stored in the line storage means; original image data read from the first line storage means; A thermal printer comprising a selection unit for selecting one of the original image data read from the line storage unit and the operation data generated by the operation unit and inputting the image data to be used for the main scanning to the printing unit; The original image data stored in the first line storage means selected by the means, the original image data stored in the second line storage means, , By inputting the operation data either the printing means from said operation means,
The operation data is inserted in the sub-scanning direction of the original image data to realize high-density recording in the sub-scanning, and the first line storage unit and the second line storage unit are used as one continuous storage unit. Original image data having twice the number of line pixels as normal is stored, and one line of original image data stored in the first line storage unit and the second line storage unit is input to the printing unit via the selection unit. A thermal printer comprising a data processing means for realizing printing twice as many as the number of pixels to be main-scanned by performing normal scanning. 2. An original image data is written only in said first line storage means, and only said input from said first line storage means is selected by said selection means, or
A data processing unit that writes original image data only to the second line storage unit, and that allows only the original image data to be selected by selecting only the input from the second line storage unit in the selection unit. The thermal printer according to claim 1, further comprising: 3. A data processing means for performing arithmetic processing on the original image data at an input stage of the original image data, and an output of the second arithmetic means and the original image data (the second arithmetic means). Is provided, and the output of the second selection means is connected to the input of the first line storage means and the input of the second line storage means, and arithmetic processing is performed in the main scanning direction. 3. A thermal printer according to claim 1, wherein said thermal printer is a data processing means which can select printing of the original image data subjected to the processing and printing of the original image data not subjected to the arithmetic processing. 4. A first line storage means for storing one line of input image data (hereinafter referred to as original image data), and a first line storage means for storing original image data and image data read from the first line storage means. Calculating means for generating new image data (hereinafter, referred to as calculation data) based on the original data, first selecting means for selecting one of the original image data and the calculation data from the calculating means, A second line storage unit for storing an image input from the selection unit, and selecting and printing one of image data read from the first line storage unit and image data read from the second line storage unit In the thermal printer comprising second selecting means for inputting to the means, the original image data stored in the first line storing means selected by the second selecting means is stored. By inputting either the data or the operation data stored in the second line storage unit to the printing unit, the operation data is inserted in the sub-scanning direction of the original image data to realize high-density sub-scan recording. The first line storage means and the second line storage means are used as one continuous storage means, and the number of pixels per line is twice as large as the original image data, and the first line storage means Means and a data processing means for realizing printing of twice the number of pixels to be main-scanned by inputting one line of original image data stored in the second line storage means to the printing means. And a thermal printer. 5. An original image data which can be written only in said first line storage means and an output of said selection means can be fixed to original image data read out from said first line storage means. 5. The thermal printer according to claim 4, wherein only printing can be selected. 6. A line storage unit for storing one line used for main scanning in a printing unit, a pixel storage unit for storing image data read out from the line storage unit on a pixel-by-pixel basis, Calculating means for generating new image data (hereinafter referred to as operation data) based on the stored image data and image data input to the printer (hereinafter referred to as original image data); In a thermal printer comprising selecting means for selecting one of operation data and original image data and inputting the selected image data to the line storage means,
The selecting means selects one of the operation data and the original image data, and stores the selected image data in the line storage means, thereby inserting the operation data in the sub-scanning direction of the original image data to increase the sub-scanning height. A thermal printer comprising data processing means for realizing density recording. 7. The thermal printer according to claim 6, wherein an output of said selecting means can be fixed to original image data, and printing of only the original image data can be selected.