JPH0848057A - Color recording method - Google Patents

Abstract

PURPOSE:To provide a color recording method capable of realizing stable recording characteristics without providing a special transfer mechanism. CONSTITUTION:The image data read from a photosensor 1 passes through an A/D conversion part 2, a color conversion part 3 and an UCR.black plate generation part 4 to be converted to four-color printing data which is, in turn, accumulated in a printing data memory part 5. A dither pattern determination part 7 has patterns different corresponding to respective colors and sends the dither patterns D1 corresponding to colors to a binary data convertion part 8 according to the control of a printing control part 6. The binary data conversion part 8 forms binary data D3 filling a predetermined area on the basis of the values of printing data D2 of respective colors according to the dither patterns D1. A thermal head driving IC 9 sends the binary data D3 to a thermal head 10 according to the control of the printing control part 6 to perform actual printing. The dither patterns of respective colors are put in order so that respective colors do not overlap as much as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color recording method capable of full-color recording in various recording devices.

[0002]

2. Description of the Related Art Conventionally, as a color recording apparatus capable of full-color recording, for example, a thermal transfer printer, an ink jet printer, a laser printer or the like has been developed. In these recording devices, full-color recording is realized by using three or four colors.

For example, as one of recording devices using a thermal head, there is a fusion type. The fusion type can print with less energy than the sublimation type, and the cost is low. But,
Since the density of the ink donor film itself cannot be changed by changing the applied energy, it is difficult to perform multi-gradation recording. Therefore, a matrix method such as a dither method, JP-A-60-248074, or JP-A-3-219969.
Area scanning method in which the gradation is changed by changing the heat generating area by a sub-scanning division method as described in Japanese Patent Publication No. 59-76264 or a heat concentration method as described in Japanese Patent Application Laid-Open No. 59-76264. Etc. are used to express the gradation in a pseudo manner.

FIG. 9 is a partial sectional view showing an example of a fusion type thermal transfer recording apparatus. In the figure, 31 is a platen, 32 is a transfer paper, 33 is an IDF, 34 is a base film, 35 is ink, and 36 is a thermal head. The fusion type thermal transfer recording apparatus shown in FIG. 9 shows an example in which a thermal head having the same size as the paper width is used. The IDF (ink donor film) 33 is configured by coating a base film 34 with a heat-meltable ink 35. The IDF 33 and the transfer target paper 32 are overlapped and passed between the thermal head 36 and the platen 31. The ink 35 on the IDF 33 is melted by energizing the thermal head 36, and the pressure applied to the platen 31 increases the adhesiveness between the transfer paper 32 and the ink, so that the ink 35 is separated from the base film 34 and the transfer paper 32 is transferred. Is transferred to and recorded.

FIG. 10 is a cross-sectional view of a transfer target paper on which recording is performed by a fusion type thermal transfer recording device. On the surface of the transfer paper 32 on which recording is performed as shown in FIG.
The ink 35 has been transferred. When the surface of the transfer paper 32 is flat, good recording is performed as shown in FIG. However, if the surface smoothness of the transfer-receiving paper 32 is poor, as shown in FIG. 10B, a portion where the adhesiveness between the transfer-receiving paper 32 and the ink is not sufficiently obtained occurs, and transfer failure occurs. Therefore, synthetic paper having good surface smoothness is used as the transferred paper 32, or plain paper having poor smoothness is used by applying a transparent smoothing layer on the surface in advance.

As described above, when performing color halftone recording, for example, three colors of cyan, magenta, and yellow are used.
Various colors are expressed by superimposing colors or four colors with black added thereto at an arbitrary ratio. Therefore,
The overlapping ink may be directly transferred onto the transfer paper or may be transferred onto another color.

FIG. 11 is a sectional view of a transfer paper showing an example when color recording is performed by the fusion type thermal transfer recording apparatus. In the figure, 37 to 39 are inks of different colors. For example, consider a case where recording is performed using the three colors of cyan, magenta, and yellow described above. The ratio of the printed area within one pixel will be called the printed area ratio. It is assumed that there is a color in which the print area ratio of yellow is 10%, the print area ratio of magenta is 50%, and the print area ratio of cyan is 100%. Printing is performed for the three colors in the same position in the pixel so that the area increases with the same pattern. At this time,
FIG. 9 shows a state where ideal printing is performed in the order of yellow, magenta, and cyan. In FIG. 9, the ink 37 is yellow, the ink 38 is magenta, and the ink 39 is cyan. Although all yellow is transferred onto the transfer paper, 20% of magenta will be transferred onto the yellow ink and 50% of cyan will be transferred onto the magenta ink.

FIG. 12 is a sectional view of a transfer paper showing another example when color recording is performed by the fusion type thermal transfer recording apparatus. In the fusion type thermal transfer recording apparatus, as shown in FIG. 11, inks of a plurality of colors are superposed and recorded. At this time, if the respective colors are printed in good overlap, for example, as shown in FIG.
Recording is performed in the state shown in FIG.
However, the ink on the transfer paper 32 is ideally IDF.
Should be completely transferred from the transfer paper 32 and ID.
When the F33 is peeled off, a part of the ink may remain on the IDF 33 due to the adhesiveness between the base film 34 and the ink. In such a portion, in the process in which the once melted ink is solidified again and peeled off, a crack occurs between the transferred ink and the remaining ink, and the transferred ink surface is not smooth. Therefore, as shown in FIG. 12B, when the surface of the ink 37 is not smooth, the ink 38 superposed on the surface of the recording paper 32 has some transfer defects as in the case where the surface of the recording paper 32 is not smooth. appear. Further, when the recording paper 32 and the surface of the ink are overlapped on the ink, there is a difference in the adhesive force of the ink, which increases the transfer failure. Due to such a transfer failure, image quality is deteriorated such as color misregistration.

In order to express a stable color, the transfer characteristics of each color are important. Even if a transfer paper having a good surface smoothness is used, depending on the surface state of the ink already transferred, the above-described As shown in FIG. 12B, transfer failure occurs in the ink that is overlaid. If three or four color inks are stacked, this problem occurs at the overlapping surface of the respective color inks. This problem is not affected by heat storage and becomes a problem when the printing area ratio is low, resulting in the problem that the color reproducibility is not stable.

As a method for improving the surface property of the formed image,
For example, as described in Japanese Patent Laid-Open No. 3-197186, the time from transfer of ink to separation is extended,
A method has been proposed in which the ink is sufficiently cooled and then peeled off. However, this method has a problem that the mechanism becomes complicated and the size of the device also increases.

Further, for example, Japanese Patent Laid-Open No. 63-293068.
As described in Japanese Patent Publication, there is a technique for changing the amount of heat generation when printing is performed by superimposing it on another color. However, a drive circuit for changing the amount of heat generation is required. Also, as described in Japanese Patent Laid-Open No. 63-312862, in order to compensate for the decrease in density when printing is performed overlaid, there is also one that performs printing by correcting the print data of the colors overprinted. In this technique, the surface of the printed transfer paper remains in the state shown in FIG. 12B, the surface flatness is not improved, and the color reproducibility is not stable.

In addition to the thermal transfer recording apparatus described above, for example,
In the inkjet type recording apparatus and the like, inconvenience occurs when recording is performed by overlapping each color. For example, when inks of a plurality of colors are ejected on the same dot, the amount of ink at the landing position increases. Therefore, it is absorbed by the recording paper and spreads on the surface of the recording paper until it is dried, causing problems such as bleeding and uneven density.

As described in JP-A-59-76264 and JP-A-5-77493, it is possible to record dots of respective colors so that they do not overlap each other. There is a drawback that the area for expressing dots becomes large and high density recording cannot be performed. In addition, when the entire surface is printed with one color, the printing areas of the other colors are omitted, and the non-printed portion reduces the overall density, which makes it impossible to perform high-density printing.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a color recording method which can realize stable recording characteristics without a special transfer mechanism. The purpose is.

[0015]

According to a first aspect of the present invention, in a color recording method in which printing is performed using a plurality of colors, each color has the same area corresponding to one pixel. A printing area is divided, the printing area is divided into a matrix, and the individual cells of the divided matrix are sequentially filled according to a predetermined pattern to change the printing area to represent a halftone and for each color to be printed. It is characterized in that the predetermined pattern for filling the matrix is different.

In a second aspect of the present invention, in a color recording method for printing using a plurality of colors, the same area for each color corresponds to one pixel as a print area, and the print area is sub-scanned. Direction is divided into a plurality of partial areas, and the divided partial areas are sequentially filled in a predetermined order to change the printing area to represent a halftone and fill the partial areas for each color to be printed. It is characterized in that the predetermined order is different.

According to a third aspect of the present invention, in a color recording method in which printing is performed using a plurality of colors, the same area for each color corresponds to one pixel as a printing area, and the printing area is matrix-shaped. And the printing area is changed by sequentially filling the individual cells of the divided matrix according to the pattern, and the halftone is expressed.
It is characterized in that the print history is stored for the colors that have already been recorded, and the pattern for filling the matrix is determined for each color to be printed thereafter by referring to the print history. is there.

The method according to claim 4, wherein the pattern is determined.
As in the invention described in (1), a plurality of patterns for filling one pixel are prepared in advance, and the patterns can be determined so that different colors do not overlap among the patterns as much as possible. Alternatively, as in the fifth aspect of the invention, it is possible to adopt a pattern in which cells having the preceding color and having no print history are preferentially filled.

[0019]

According to the present invention, in the invention described in claim 1, the same area for each color corresponds to one pixel as a print area, each print area is divided into a matrix, and the divided matrix is obtained. Since the printing area is changed by sequentially filling the individual cells in accordance with a predetermined pattern to express a halftone, and the predetermined pattern for filling the matrix is changed for each color to be printed, the printing is performed. In particular, the probability of color overlap is reduced particularly in the low gradation region, and as a result, the probability of print failure due to overlapping printing is reduced, and stable color reproduction can be achieved.

Further, in the invention described in claim 2,
Instead of dividing the print area into a matrix, the print area is divided into a plurality of partial areas in the sub-scanning direction, and the divided partial areas are sequentially filled in a predetermined order to change the print area,
In addition to expressing a halftone, the predetermined order of filling the partial areas is made different for each color to be printed, the probability of color overlap is reduced, and stable color reproduction is possible.

In a third aspect of the present invention, a print area is divided into a matrix shape, and a pattern used for sequentially filling individual cells of the divided matrix is printed in a color that has already been recorded. Determine by referring to the history.
This makes it possible to print so that the area increases with different patterns while referring to the transfer status of the previous color when transferring each color, and the probability that the print areas of each color overlap, especially in the low gradation area, decreases, resulting in transfer. The probability of defects is reduced and stable color reproduction is possible. At this time, as in the invention described in claim 4, a plurality of patterns are prepared and selectively used, or like the invention described in claim 5, there is no print history of the previous color. By controlling the cells to be filled preferentially, different colors can be printed so as not to overlap with each other.

[0022]

1 is a block diagram showing an example of a color recording apparatus for realizing a first embodiment of a color recording method of the present invention. In the figure, 1 is a photo sensor, 2 is an A / D conversion unit, 3 is a color conversion unit, 4 is a UCR / black plate generation unit, 5 is a print data storage unit, 6 is a print control unit, and 7 is a dither pattern determination unit. , 8 is a binary data conversion unit, 9 is a thermal head drive IC, and 10 is a thermal head. FIG. 1 shows a thermal transfer type recording apparatus using a thermal head as an example of the color recording apparatus.

The photosensor 1 converts an image into an electric signal for each color of red, green and blue and reads it. A
The / D converter 2 converts an analog signal of an image read by the photo sensor 1 into a multi-valued digital signal. The color conversion unit 3 converts signals of red, green, and blue colors into signals of cyan, magenta, and yellow colors. U
The CR / black plate generator 4 removes the ground color,
The black portion is extracted from the signals of each color of magenta and yellow, and print data of four colors of cyan, magenta, yellow and black is created. The print data storage unit 5 stores print data of four colors of cyan, magenta, yellow, and black, respectively.

The print control unit 6 reads out print data from the print data storage unit 5 and controls the dither pattern determination unit 7, the thermal head drive IC 9, and the like.
The dither pattern determination unit 7 has a different dither pattern for each color, and sends the dither pattern to the binary data conversion unit 8 according to the color to be printed. Binary data converter 8
Creates binary data corresponding to the value of the print data read from the print data storage unit 5 according to the given dither pattern. The thermal head drive IC 9 sends a drive signal to the thermal head 10 according to the binary data. In the thermal head 10, the heating elements corresponding to the dots driven by the thermal head driving IC 9 generate heat, and as shown in FIG. 9 described above, actual printing is performed on the transfer paper.

The data R1, G1, B1 read from the photo sensor 1 and the like are converted into digital signal data R2, G2, B2 by the A / D converter 2, and the ink used for printing is printed by the color converter 3. Data C1, M1, Y corresponding to color
Color converted to 1. Further, print data Y corresponding to print colors including black passes through the UCR / black plate generation unit 4.
2, M2, C2, K2 converted to print data storage unit 5
Is accumulated in Subsequently, the print data D2 of each color is converted into the binary data D3 in the binary data conversion unit 8 according to the dither pattern D1 given from the dither pattern determination unit 7 so as to fill a certain area. When the print start enable signal S3 is input from the print control unit 6, the thermal head driving IC 9 sends the print energy D4 to the thermal head 10 by ANDing the bits for which the binary data D3 is 1 to perform the actual printing. Is performed.

FIG. 2 is an explanatory diagram of an example of the dither matrix pattern in the first embodiment of the present invention. The dither matrix pattern shown in FIG. 2 has 1 of each color.
It is shown that the area for printing pixels is divided into 16 matrixes of 4 × 4, and the print areas are increased by sequentially filling the print areas from the small numbers described in each matrix. As a result, printing is performed according to the pixel density. For example, when printing half the area, 1 to 8 divided areas are printed. 2A to 2D are arranged so that the matrix is filled in a different order. By associating these four patterns with the colors of yellow, magenta, cyan, and black, respectively, it is possible to perform printing in the low-density portion so that the print areas of the respective colors do not overlap as much as possible. Of course, other patterns may be used, and the size of the matrix is not limited to 4 × 4.

For example, when printing the first color yellow,
First, the yellow print start signal S1 is sent from the print control unit 6 to the print data storage unit 5, the yellow print data is read, and the print count signal S2 is sent to the dither pattern determination unit 7. Dither pattern determination unit 7
Corresponding to the color used, for example, 4 shown in FIG.
The dither patterns of different types are stored, and the dither pattern determined by counting the print count signal S2 is read. Here, the dither pattern shown in FIG. 2A is read corresponding to the first color yellow, and the yellow print data is converted into binary data by the binary data converter 8 according to this pattern. , To the thermal head 10.

Also in the next printing of magenta of the second color, when the print count signal S2 is sent to the dither pattern determining section 7, the dither pattern shown in FIG. 2B is selected and the binary data converting section is selected. Sent to 8. The binary data conversion unit 8 converts the magenta print data into binary data in accordance with the sent dither pattern and sends the binary data to the thermal head 10. Similarly, cyan follows the dither pattern shown in FIG. 2C, and black follows the dither pattern shown in FIG.
Printing is performed according to the dither pattern shown in FIG.

Based on the case where one pixel is divided into 16 pieces as in the example shown in FIG. 2, the overlapping of the respective colors will be considered. When all colors are in the 1 to 4 level range,
In the conventional technique in which the same dither matrix is used for each color, the inks always overlap. However, the present invention eliminates it at all.

Other than that, there is no overlap even if, for example, yellow has 6 levels, magenta has 1 level, cyan has 4 levels, and black has 4 levels. In this way, even if there is no overlap in many colors, or if there is overlap in only one part, the probability increases. As a result, stable recording characteristics can be assured, and high-quality color halftone recording can be obtained.

Next, a second embodiment of the present invention will be described. In the above-described first embodiment, the dither pattern is determined for each color, and the print area is sequentially filled according to the pattern. However, by selectively using these dither patterns, it is possible to further reduce the overlap.

FIG. 3 is a block diagram showing an example of a color recording apparatus for realizing the second embodiment of the color recording method of the present invention. In the figure, the same parts as those in FIG. Reference numeral 12 is a print history storage unit.
Note that the parts shown in FIG. 1A may have the same structure, and are omitted here. The print history storage unit 12 stores the patterns printed so far. The dither pattern determination unit 7 has a plurality of dither patterns, selects a dither pattern from the print patterns up to the previous color stored in the print history storage unit 12, and sends it to the binary data conversion unit 8.

FIG. 4 is an explanatory view of a concrete print pattern for explaining the second embodiment of the color recording method of the present invention. In the figure, 21 is a print area corresponding to one pixel, 22
Numerals 25 to 25 indicate portions printed with the respective colors. Here, the part printed in yellow is 2
2, the portion printed with magenta is 23, the portion printed with cyan is 24, and the portion printed with black is 25. As a specific example, as in the first embodiment described above, one pixel is configured by a 4 × 4 matrix, and the gradation is from 0 level to 16 levels. Four
The color gradation is 6 levels for yellow, 4 levels for magenta,
Consider a pixel in which cyan is transferred at 5 levels and black is transferred at 1 level. Further, it is assumed that the four patterns shown in FIG. 2 are prepared in advance as dither patterns.

For example, when printing the first color yellow,
First, a yellow print start signal S1 is sent from the print control unit 6 to the print data storage unit 5, and the yellow print data is read. At the same time, the print count signal S2 is sent to the dither pattern determination unit 7, and the information in the print history storage unit 12 is erased. Dither pattern determination unit 7
Sends the pattern of the first color, for example, the dither pattern shown in FIG. 2A to the binary data conversion unit 8. The binary data conversion unit 8 converts the yellow print data into binary data and sends it to the thermal head 10. The first yellow color is
Since the gradation is 6 levels, the areas 1 to 6 of the dither pattern shown in FIG. 2A are printed and recorded as shown in FIG. 4A. At the same time, the dither pattern is sent to the print history unit 12 and stored as a print history.

Next, in the printing of the magenta of the second color, when the printing frequency coefficient signal S2 is sent to the dither pattern determining section 7, the dither pattern determining section 7 prints the data stored in the printing history storage section 12 this time. By referring to the history information, the pattern in which the yellow print area that has already been printed and the magenta print area have the smallest overlap is determined and selected. The second color magenta has four gradation levels. Figure 2
In the dither pattern shown in (B), an overlap with the already printed yellow occurs, but no overlap occurs in FIGS. 2 (C) and 2 (D). Therefore, as the dither pattern used for printing the magenta of the second color, the dither pattern shown in FIG. 2C or 2D can be selected.
Here, it is assumed that the dither pattern shown in FIG. 2C is selected.

The dither pattern for the second color determined in this way is sent to the binary data conversion section 8. The binary data converter 8 converts the magenta print data into binary data in accordance with the sent dither pattern shown in FIG. 2C and sends it to the thermal head 10. In this way, the pixels are filled as shown in FIG. At the same time, the dither pattern is sent to the print history storage unit 12. The print history storage unit 12 stores a logical sum pattern of the dither pattern used in the previous yellow printing and the dither pattern used in the current magenta printing. This allows
An area in which at least one of yellow and magenta is printed is stored as a print history.

Similarly, for the third color cyan, referring to the print histories of yellow and magenta stored in the print history storage unit 12, as a pattern with little overlap with these patterns, a pattern shown in FIG. Select the dither pattern shown. Then, using the selected dither pattern, the cyan print data of the third color is converted into binary data and printed. Since the gradation of cyan of the third color is 5, FIG.
The pixels are filled as shown in. Similarly, for the fourth color black, the dither pattern shown in FIG. 2B is selected by referring to the print histories of yellow, magenta, and cyan, and conversion into binary data and printing are performed. Finally, Figure 4
As shown in (D), four colors are printed.

As described above, since a pattern in which a plurality of colors do not overlap as much as possible is selected and used, the probability that different colors overlap is reduced, and stable color reproduction is possible.

In the above description, the dither pattern determining unit 7
Although the four dither patterns shown in FIG. 2 have been set in advance, the set dither patterns are not limited to the four patterns shown in FIG. 2 and can be changed as appropriate. Further, the number of dither patterns to be set is not limited to four, and it is also possible to set more patterns and select them appropriately.

In the above example, the print history storage unit 12
In the above, the logical sum of the print patterns of the colors printed up to that time is stored, but the print patterns of the respective colors may be stored and, for example, a pattern that does not overlap in triple or quadruple can be selected. it can.

In the above-mentioned second embodiment, the dither method is taken as an example and selected from four types of dither patterns. However, according to a certain order, the unfilled portions are preferentially filled. Good. For example, when four types of ink are transferred in the same manner as in the above-described embodiment, when the ink of FIG.
Using the printing order of the dither pattern shown in, yellow fills 1 to 6 of the matrix, followed by magenta 7 to 1.
0, cyan fills 11 to 15, and black fills 16. Here, if the number of gradations of four colors exceeds the number of matrices, it is sufficient to start from 1 again. of course,
You may make it fill up in another order. With this configuration, it is possible to further reduce the overlap of the colors.

The above-described embodiment is not limited to the dither method, but can be applied to all area gradation methods in which area modulation is performed by sequentially filling a region in one pixel.

The above-described embodiment can be applied not only to the thermal transfer type recording apparatus. For example, even in an inkjet type recording apparatus, it is possible to express the shade of each color by using a dither pattern and perform full-color printing. At this time, the printing in each pixel is performed so that the dots of each color overlap. At this time, as described above,
By using dither patterns of different patterns corresponding to the colors used, it is possible to perform printing so that a plurality of colors do not overlap as much as possible. This improves color development and prevents bleeding and dot enlargement,
A good image can be obtained.

Next, a third embodiment of the present invention will be described. In the third embodiment, an example using the sub-scanning division method in which the width of one pixel in the sub-scanning direction is modulated to change the area is shown. The sub-scanning division method is, for example, the above-mentioned Japanese Patent Laid-Open No.
No. 248074, Japanese Patent Laid-Open No. 3-219969, and the like.

FIG. 5 is an explanatory diagram of an example of area modulation in the third embodiment of the present invention. In the figure, 21 indicates a print area corresponding to one pixel, and 22 to 25 indicate portions printed by each color. In this sub-scanning division method, the printing area 21 corresponding to one pixel is divided in a direction orthogonal to the sub-scanning direction, and the divided small areas are sequentially filled, thereby changing the printing area and gradation printing. It is something to do. For example, as shown in FIGS. 5A to 5C, the print area is sequentially filled from one side of the print area. Figure 5
FIG. 5A shows the first gradation, FIG. 5B shows the state of the eighth gradation in which half the area is filled, and FIG. 5C shows the 16th gradation in which the entire area is filled. Represents the state.

At this time, the control of the thermal head divides the printing time for one line in the main scanning direction by the number corresponding to the number of divisions of the printing area 21, and inputs energy for the time corresponding to the number of gradations. That is, in FIG. 5A, when the number of divisions is n, the energy is applied to the thermal head for 1 / n time, and the energy is applied for 1/2 time in FIG. 5B.

In such a sub-scanning division method, by shifting the print start position of each color depending on the color, it is possible to print the colors so that they do not overlap as much as possible. For example, as shown in FIG. 5D, the print start position is shifted by 1/4 in the sub-scanning direction of one pixel. Here, the portion printed in yellow is 22, the portion printed in magenta is 23, the portion printed in cyan is 24, and the portion printed in black is 25. The density is set to 0 to 16, and for example, in the print data of one pixel, yellow is 2, magenta is 3, cyan is 1,
When black has a density of 4, as shown in FIG. 5 (E), one pixel is printed without overlapping for each color. Thus, for example, in the case of printing with low density, the probability of overlapping printing can be reduced.

FIG. 6 is an explanatory diagram of an example of the print start position in the third embodiment of the present invention. In FIG. 5E, the printing area of each color is contained within the printing area 21 of one pixel. As shown in FIG. 6A, for example, when the print start position is at the beginning of the print area of one pixel, printing can be performed simply by determining the print width corresponding to the value of the print data. For example, as shown in FIG. 6C, when the print start position is half the print area of one pixel and the print data value is lower than the half density, the print area Printing may be performed from the 1/2 position with a width corresponding to each print data value. However, when the value of the print data exceeds the density of 1/2, the print area of one pixel runs out. In order to prevent this, when the value of the print data exceeds half the density, the print start position is moved forward so that the print data fits within the print area of one pixel. The same is true when the print start position is shifted by 1/4 and 3/4, and as shown in FIGS. 6B and 6D, the density of the print data is 3/4 and 1/4, respectively. If it exceeds, the print start position may be shifted forward so that the print start position fits within the print area of one pixel.

FIG. 7 is a block diagram showing an example of a color recording apparatus for realizing the third embodiment of the color recording method of the present invention. In the figure, the same parts as those in FIG. Reference numeral 11 is a sub-scanning division pattern determination unit. The third embodiment shown in FIG. 7 also shows a thermal transfer type recording apparatus using a thermal head. The configuration up to the print data storage unit 5 is the same as that in FIG. 1A, and is omitted in FIG. 7.

The sub-scanning division pattern determining unit 11 divides the print area of one pixel in the direction orthogonal to the sub-scanning direction, and has a print start position for filling each divided small area for each color. ing. Upon receiving the print number counting signal S2 output from the print control unit 6, the print start position changing signal E1 corresponding to the print color is sent to the binary data converting unit 8 based on this. The binary data conversion unit 8 outputs the print start position change signal E1.
Then, based on the print data read from the print data storage unit 5, the print start position and the print data are sent to the thermal head drive IC 9. The thermal head drive IC 9
Printing is performed by driving the thermal head 10 based on the print start position and the print data value passed from the binary data conversion unit 8.

As an example, the case of the second color magenta will be described. The sub-scanning division pattern determination unit 11 gives a print start position change signal E1 corresponding to magenta to the binary data conversion unit 8. For example, as shown as an example in FIG. 5 described above, it is assumed that the print start position change signal E1 is given to the binary data conversion unit 8 so that the position shifted by ¼ becomes the print start position. . The binary data conversion unit 8
When the magenta print data value is 3/4 or less of the maximum density, the print energy input start time is 1/4 of one pixel.
The data is sent to the thermal head drive IC 9 so as to be delayed only by this. The printing energy input time is determined by the value of the printing data. Further, when 3/4 or more of one pixel is filled, the print start position is shifted forward according to the value of the print data to prevent the print area from protruding the pixel.

FIG. 8 is an explanatory diagram of a pulse driving method in the thermal head driving IC 9. The thermal head drive IC 9 can apply printing energy to the thermal head 10 by a pulse. At this time,
The print width corresponds to the number of pulses applied to the thermal head 10. That is, by applying the number of pulses corresponding to the value of the print data to the thermal head 10, it is possible to perform printing with the print width corresponding to the value of the print data.

For example, in the above-mentioned magenta printing, 1 /
The position shifted by 4 is the print start position. Therefore, as shown in FIG. 8B, no pulse is transmitted during the first ¼ period. Then, after a lapse of 1/4, the number of pulses corresponding to the value of the print data is transmitted. At this time, if the number of pulses exceeds 3/4 of the whole,
As shown in (E), the print start position is shifted forward by a number exceeding 3/4, and control is performed so that the pulse falls within the print area of one pixel. By performing the pulse control as shown in FIGS. 8B to 8E, the pattern of each one pixel shown in FIG. 6B is printed.

For the third color, the first shift position may be set to 1/2 of one pixel, and for the fourth color, the shift position may be set to 3/4. For the third and fourth colors, if the print data values exceed 1/2 and 1/4, respectively, the print start position may be shifted forward so that the print start position is within the print area.

By controlling in this way, as in the case of the dither method shown in the first embodiment, it is possible to reduce the probability of printing a plurality of colors in an overlapping manner and obtain a high quality printed image. Become.

Of course, not limited to the above control method, for example, the print data may be referred to, and the print start position may be determined so that the printed areas do not overlap as much as possible. For example, when a specific color is dark. It is also possible to shift the print start positions of other colors back and forth. Alternatively, the position following the first color is set as the print start position for the second color,
It is also possible to employ a method in which the print area is continuous according to the print data, such that the position following the second color is set as the print start position for the third color. In this case, when the continuous print area extends beyond the pixel area, the print area may be set with reference to the print data so as to return to the upper position.

In the above-described embodiments, the first and second embodiments can be applied to recording methods using various heads such as a thermal transfer type head using a thermal head and an ink jet type head. It can be said that the third embodiment is a recording method suitable for a thermal transfer type head using a thermal head, since a head for printing an elongated area is suitable.

[0058]

As is apparent from the above description, according to the present invention, when a plurality of colors are printed in the same one pixel area, it is possible to print each color so as not to overlap each other as much as possible. There is an effect that the above-mentioned recording characteristics can be guaranteed and a high quality color halftone recorded image can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a color recording apparatus that realizes a first embodiment of a color recording method of the present invention.

FIG. 2 is an explanatory diagram of an example of a dither matrix pattern according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing an example of a color recording apparatus that realizes a second embodiment of the color recording method of the present invention.

FIG. 4 is an explanatory diagram of a specific print pattern for explaining the second embodiment of the color recording method of the present invention.

FIG. 5 is an explanatory diagram of an example of area modulation according to the third embodiment of the present invention.

FIG. 6 is an explanatory diagram of an example of a print start position according to the third embodiment of the present invention.

FIG. 7 is a block diagram showing an example of a color recording apparatus that realizes a third embodiment of the color recording method of the present invention.

FIG. 8 is an explanatory diagram of a pulse driving method in the thermal head driving IC 9.

FIG. 9 is a partial cross-sectional view showing an example of a fusion type thermal transfer recording device.

FIG. 10 is a cross-sectional view of a transfer target paper on which recording is performed by a fusion type thermal transfer recording device.

FIG. 11 is a cross-sectional view of a transfer paper showing an example when color recording is performed by a fusion type thermal transfer recording device.

FIG. 12 is a cross-sectional view of a transfer paper showing another example when color recording is performed by the fusion type thermal transfer recording device.

[Explanation of symbols]

1 ... Photo sensor, 2 ... A / D converter, 3 ... Color converter,
4 ... UCR / black plate generation unit, 5 ... Print data storage unit, 6 ...
Print control unit, 7 ... Dither pattern determination unit, 8 ... Binary data conversion unit, 9 ... Thermal head drive IC, 10 ... Thermal head, 11 ... Sub-scanning division pattern determination unit, 12 ... Print history storage unit.

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Claims (5)

[Claims] 1. A color recording method for performing printing using a plurality of colors, wherein the same area for each color corresponds to one pixel as a printing area, the printing area is divided into a matrix, and the divided areas are divided. The printing area is changed by sequentially filling the individual cells of the matrix in accordance with a predetermined pattern to represent a halftone, and the predetermined pattern for filling the matrix is made different for each color to be printed. And color recording method. 2. In a color recording method for printing using a plurality of colors, the same area for each color corresponds to one pixel as a printing area, and the printing area is divided into a plurality of partial areas in the sub-scanning direction. Then, the printing area is changed by sequentially filling the divided partial areas in a predetermined order to represent a halftone, and the predetermined order of filling the partial areas is made different for each color to be printed. A color recording method characterized by the above. 3. A color recording method for printing using a plurality of colors, wherein the same area for each color corresponds to one pixel as a printing area, and the printing area is divided into a matrix and the divided areas are divided. The print area is changed by sequentially filling the individual cells of the matrix in accordance with the pattern to represent the halftone, and the print history of the colors that have already been recorded is stored and the print history is referenced. A color recording method, wherein the pattern for filling the matrix is determined for each color to be printed thereafter. 4. When determining the pattern, a plurality of patterns for filling one pixel are prepared in advance,
4. The color recording method according to claim 3, wherein the patterns are determined so that different colors in the patterns do not overlap as much as possible. 5. The color recording method according to claim 3, wherein when the pattern is determined, a pattern in which cells having no print history of the previous color are preferentially filled.