JPH06305169A - Color image recording method - Google Patents

Abstract

PURPOSE:To make a stripe or gap between lines inconspicuous if it is caused by irregularities in paper feeding or the like by a method wherein in a serial printer, ink dots of two or more colors are recorded in order per line, and a travel width of recording paper in a main scanning direction is determined correspondingly to the number of colors. CONSTITUTION:A thermal head 10 is provided with a plurality of heating elements 11 arranged in a line in a main scanning direction M with a length L. While the thermal head 10 travels once in a sub-scanning direction S, a line of a width L is recorded on recording paper. In an ink ribbon, ink areas of N colors are provided at a fixed pitch. Upon completion of one line recording, the thermal head 10 is returned to the initial position of the thermal head 10 and a ribbon cassette. At the same time, an ink ribbon is fed to be set at a recording position of a next ink area. The recording paper is fed in the main scanning direction by a 1/3 line. Therefore, if lines are overlapped with each other, only one color is added at the lapped part. If a gap is generated, the gap is surely recorded with the other colors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a color image recording method for a serial printer in which a thermal head moves in a sub scanning direction and a recording paper moves in a main scanning direction.

[0002]

2. Description of the Related Art As a color image recording method, a color thermal recording method, a color ink jet recording method, a color electrophotographic recording method and the like are known. Recently, attention has been paid to a color heat recording method because of the miniaturization of the apparatus and the ease of maintenance. This color thermal recording method includes color thermal recording in which a color image is directly recorded on a thermal recording sheet and color thermal transfer recording in which ink of an ink film is transferred to a recording paper. In the color thermal transfer recording, there are a melt type in which a melted ink is transferred to a recording paper and a sublimation type in which the amount of the ink transferred to the recording paper changes according to thermal energy.

For example, in color thermal transfer recording, a recording head in which a plurality of recording elements are arranged in the main scanning direction is used, and one line is recorded while moving the recording head in the sub scanning direction.
A serial printer of the type that feeds paper in the main scanning direction and records the next one line is often used.

[0004]

However, in the serial printer as described above, the edges of adjacent lines in the main scanning direction overlap each other due to stretching of the paper, uneven feeding of the paper, etc. There is a drawback that the density is increased and streaks are formed in the sub-scanning direction, or conversely, a gap is formed between the lines so that the recording paper has a streak in the sub-scanning direction.

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and an object of the present invention is to provide a color image recording method for a serial printer in which stripes and gaps between lines caused by unevenness of paper feed are inconspicuous. Is.

[0006]

In order to achieve the above object, a color image recording method of the present invention is a method of recording ink dots of N colors (N is an integer of 3 or more) one line at a time and recording them. The width of movement of the paper in the main scanning direction is 1 / N line.

[0007]

[Function] Since different colors are recorded while being offset from each other,
Even if the lines overlap each other, they will be one color at a time, and this overlap is not noticeable. Even if a gap is generated between lines of a certain color, the other color is always recorded in this gap, so that the gap is not conspicuous.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 3 showing a fusion type thermal transfer recording apparatus for carrying out the color image recording method of the present invention, a thermal head 10 has a plurality of, for example, 48 heating elements 11 (see FIG. 1) in the main scanning direction (M). ) Are arranged in a row with a length L. While the thermal head 10 is moved once in the sub-scanning direction (S), one line having the width L is recorded on the recording paper. This one line is composed of 48 sub lines.

The ink ribbon 12 is supplied by a well-known ribbon cassette 13. The ribbon cassette 13 is mounted behind the thermal head 10, and the ink ribbon 12 is slightly pulled out from the ribbon cassette 13 and passed between the thermal head 10 and the recording paper 15. As is well known, on the ink ribbon 12, cyan, magenta, and yellow ink areas are formed at a constant pitch.

During recording, the ink ribbon 12 is brought into close contact with the recording paper 15 from behind by the thermal head 10, and the ribbon cassette 13 is moved together with the thermal head 10 in the sub-scanning direction by the head moving mechanism 16. The thermal head 10 heats the back of the ink ribbon 12 and transfers the melted or softened ink to the recording paper 15. When the recording of one line is completed, the thermal head 10
And the ribbon cassette 13 is returned to the initial position. At the same time, the ink ribbon 12 is fed, the ink area of the next color is set at the recording position, and the recording paper 15 is conveyed by 1/3 line in the main scanning direction. That is, adjacent lines of different colors overlap each other by 2/3 line. Reference numeral 17 is a platen roller, reference numeral 18 is a conveyance roller, reference numerals 19 and 20 are pulse motors and drivers for driving the platen roller 17 and the conveyance roller 18, and reference numeral 21 is a head drive unit for driving the thermal head 10.

In FIG. 4 showing the head drive unit 20, each image data of blue, green and red is converted into each image data of yellow, magenta and cyan by a look-up table memory (hereinafter referred to as LUT) 22, 23 and 24. After that, the Y frame memory 25 and the M frame memory 2
6 and C frame memories 27, respectively.

As shown in FIG. 5A, the data width of the yellow image first read from the Y frame memory 25 is set to 1/3 line. Controller 28
Is 1/3 line from the Y frame memory 25, that is, 1
Image data is read out from only six sub-lines and written in the line memory 29. After the image data written in the line memory 29 is transferred to the buffer memory 31,
It is sent to the LUT 32. The LUT 32 generates drive data for recording a dot pattern by the area gradation method. This drive data is transferred to the thermal head 10 via the contact a of the selector SW. The first recording of yellow is performed by the lower 16 heating element rows. The second and subsequent readings are performed line by line, and the yellow image is recorded on the recording paper 15 line by line.

Similarly, for each of the magenta and cyan image data, each line memory 33, 34, buffer memory 35,
36, LUTs 37, 38 and contacts b, c of the selector SW
The respective drive data are transferred to the thermal head 10 via. As shown in FIG. 5B, the data width of the magenta image first read from the M frame memory 26 is set to ⅔ line, the second and subsequent data is read line by line, and the data read last is read. The width is set to 2/3 line. Further, as shown in FIG.
The cyan image is read line by line from the C frame memory 27, and the last read width is 1/3 line.

When the first 2/3 line of the magenta image is recorded, the lower 32 heating element arrays are used, and when the last 2/3 line is recorded, the heating element array is used. The upper 32 of the are used. Further, when recording the last ⅓ line of the cyan image, the upper 16 heat generating element rows are used. According to such a recording method, even if the recording is performed by shifting each color by 1/3 line, the recorded image of each color is not displaced. In addition, single-color and two-color streaks are not formed at the first and last line edges.

Next, a recording procedure of the fusion type thermal transfer recording apparatus will be described with reference to FIGS. 1, 2 and 6. When recording,
The platen roller 17 and the transport roller 18 rotate in the arrow direction, and the leading end of the recording area of the recording paper 15 is fed to the position of the thermal head 10. The thermal head 10 and the ribbon cassette 13 are moved to the initial position at the left end in the sub-scanning direction, the ink ribbon 12 is fed, and the starting end of the yellow ink area is set below the thermal head 10.

The selector SW is set to the contact a, and the driving data of the first yellow image is transferred to the thermal head 10. This drive data drives the lower 16 heating element rows, and the thermal head 10 heats and presses the ink ribbon 12 from behind while the thermal head 10 and the ribbon cassette 13 move to the right in the sub-scanning direction. . The melted yellow ink is transferred to the recording paper 15,
As shown in FIG. 1A, the yellow image is recorded on the recording paper 15 with 1/3 line.

When the thermal head 10 moves to the right end of the recording area, heating / pressurization of the ink ribbon 12 is stopped, and the thermal head 10 and the ribbon cassette 13 are moved leftward in the sub-scanning direction. During this movement, the platen roller 17 is rotated by the pulse motor 19, the recording paper 15 is conveyed by 1/3 line, and the ink ribbon 12 is fed so that the start end of the magenta ink area is below the thermal head 10. Set.

Subsequently, the selector SW is set to the contact b, and the driving data of the first magenta image is transferred to the thermal head 10. The driving data drives 32 lower elements of the heating element array, and a magenta image is recorded on the recording paper 15 with 2/3 line. As a result, as shown in FIG. 1B, the upper end of the previously recorded yellow line and the upper end of the magenta line coincide with each other, and the upper half ⅓ line is recorded so as to overlap the yellow image. .
Next, while the thermal head 10 and the ribbon cassette 13 are returned to the initial positions, the recording paper 15 is conveyed by 1/3 line, the ink ribbon 12 is fed, and the starting end of the cyan ink area is below the thermal head 10. Is set to.

The selector SW is set to the contact c, and the driving data of the first cyan image is transferred to the thermal head 10. All 48 of the heating element arrays are driven by this drive data, and a cyan image of one line is recorded on the recording paper 15. As a result, as shown in FIG. 1C, the upper ends of the previously recorded yellow line and magenta line and the upper end of the cyan line match, and the first 1 /
Three lines are recorded with three colors overlapping, and the next ⅓ line is recorded with two colors overlapping.

Further, while the thermal head 10 and the ribbon cassette 13 are returned to the initial positions, the recording paper 15 is
Only 3/3 lines are transported. The ink ribbon 12 is fed, the yellow ink area is set under the thermal head 10, and one line of a yellow image is recorded as shown in FIG. Similarly, the recording paper 15 is 1 /
Every time 3 lines are conveyed, a magenta image (see FIG.
(See (B)) → Cyan image → Yellow image → Magenta image → ... The last yellow image, magenta image, and cyan image are recorded as 1 line, 2/3 line, and 1/3 line, respectively.
When the recording of all three colors is completed, the platen roller 17 and the conveying roller 18 are continuously rotated in the arrow direction, and the recording paper 15
Is discharged.

In the embodiment described above, the three kinds of colors for color recording are yellow, magenta and cyan. However, the present invention is not limited to this, for example, black is added to this. It may be a color. Then, in the case of this four-color recording, the paper feed is set to 1/4 line at a time. In addition, although each of the above-mentioned embodiments is the melting type thermal transfer recording, the present invention can be applied to sublimation type thermal transfer recording, thermal recording, ink jet recording and the like.

[0022]

As described above, according to the color image recording method of the present invention, ink dots of N colors are sequentially recorded line by line, and the movement width of the recording paper in the main scanning direction is 1 / N. Since the lines are used, different colors are recorded while being offset from each other. Therefore, even if the lines are overlapped with each other, each line becomes one color and the three colors do not overlap at the same time, so that the overlap becomes inconspicuous. Further, even if a gap is generated between lines of a certain color, another color is recorded in this gap, so that this gap is not conspicuous.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a state in which first lines of yellow, magenta, and cyan are recorded.

FIG. 2 is an explanatory diagram showing recording states of a second yellow line and a magenta line, respectively.

FIG. 3 is a schematic view showing a fusion type thermal transfer recording apparatus embodying the present invention.

FIG. 4 is a block diagram showing a configuration of a head drive unit.

FIG. 5 is an explanatory diagram showing how to read image data from each frame memory for yellow, magenta, and cyan.

FIG. 6 is a flowchart showing a procedure of thermal recording.

[Explanation of symbols]

 10 Thermal Head 11 Heating Element 12 Ink Ribbon 15 Recording Paper 20 Head Drive 25 Y Frame Memory 26 M Frame Memory 27 C Frame Memory

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B41J 19/76 9212-2C 35/16 A 9012-2C G06F 3/12 L 9211-2C B41J 3 / 10 101 E

Claims (1)

[Claims] 1. A recording head having a plurality of heating elements arranged in the main scanning direction is used, the recording head is moved in the sub scanning direction to record one line, and the recording paper is moved in a predetermined width in the main scanning direction. In a color image recording method of a serial printer, which moves and records a color image on recording paper with ink dots of the number N of colors, the ink dots of N colors are sequentially recorded line by line, and the main scanning direction of the recording paper is used. The color image recording method is characterized in that the moving width of 1 is set to 1 / N line.