JP2539867B2 - Printing method - Google Patents

Description

The present invention relates to a printing method for full-color display.

<Prior Art> In a dot type color printer such as an inkjet type, a thermal transfer type and a laser beam type, a method of performing color reproduction using subtractive color mixture shown in FIG. 5 is widely adopted. When the subtractive color mixture is printed, for example, the target color display is R
In the case of (red), Y (yellow) ink and M (magenta) ink are mixed to reproduce R (red) color. Similarly, G (green) is reproduced by mixing Y (yellow) ink and C (cyan) ink, and B (blue) is reproduced by mixing M (magenta) ink and C (cyan) ink.

When reproducing Bk (black) by the subtractive color mixture,
In the conventional printing method, Y (yellow) ink and M
Either the (magenta) ink and the C (cyan) ink were mixed, or only one color of Bk (black) ink was used for reproduction.

<Problems to be Solved by the Invention> However, the conventional printing method described above has the following problems because the characteristics of the color printer are not necessarily ideal. That is, in the case of displaying Bk (black) color, when three colors (Y, M, C) of ink are mixed for one dot, the ink bleeds to the surroundings, and the problem that an accurate image display cannot be achieved or 3 There is a problem that even if the colors are mixed, the color does not become accurate black. Further, when black is displayed by one color of Bk (black) ink, for example, when red and black are alternately printed as shown in FIG. 6, R (red) is displayed as Y (yellow) ink and M (magenta). ) The color is dark because the two colors of ink are mixed and superimposed on a common dot, but the black display is light because only one Bk (black) ink is used per dot. As described above, there is a problem that Bk becomes lighter in color than R, B, G, and the like. Of course, if the density of the black ink is increased, the black color can be increased, but there is a problem that the printer head is clogged.

Therefore, an object of the present invention is to provide a printing method capable of darkening a black display without causing ink bleeding or clogging of a printer head.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a printing method for expressing a color with a plurality of color inks and a black ink of a single density, to a plurality of dots to be displayed in black. Set the color order in the at least one-dimensional direction of the color ink to be printed overlaid on the black ink in the order that black display does not have a specific color tone, and set the repeating unit of this set color order as a dot element. When the black dots are printed, the color ink of a color selected according to the color order of the matrix is superimposed on the black ink and printed.

<Operation> When the black dots are printed, the color inks of the colors selected in the color order represented by the matrix are superposed on the black ink and printed.

As a result, even if the density of the black ink is fixed to a density that is about the same as the density of other color inks and does not cause clogging of the printer head, the black display is dark and the color contrast is improved. Further, at that time, since the matrix elements represent the color order of the color ink to be printed by superimposing it on the black ink in a dot order in a color order such that the black display does not have a specific color tone, ,
A black display consisting of printed black dots does not have a particular color tone.

<Example> Hereinafter, the present invention will be described in detail with reference to illustrated examples.

FIG. 1 shows that when printing color image information including shades, the dots displaying Bk (black) have one pattern of Y (yellow), M (magenta), and C (cyan), or no specific color tone. And mix
An example of a color matrix is shown in order to darken Bk (black) of the entire image and increase the contrast.

The color matrix patterns (A), (B),
(C) is for the area where Bk of the image information is printed,
This is a pattern when a 3 × 3 array is used and mixed with Bk and printed alternately. For example, as shown in FIG.
When using the above pattern (A) to print red and black alternately, the dots displaying red are mixed with two colors of ink Y and M, and the dots displaying black are printed with Y and M. , C
Alternately mix the ink of Bk with the ink of Bk and print. In this way, the color given by the color mixing pattern is mixed with Bk and printed, and the black becomes darker and the contrast increases. If these patterns (A), (B), and (C) are applied when the black areas are continuous, vertical, horizontal, or diagonal stripes may occur, so in such a case, the pattern (D ) Applies. For example, let us consider a case where it is applied to the shaded area of a full-color mountain landscape picture shown in FIG. Since the situation of this landscape painting is at night, the shaded area is Bk (black). At this time, colors other than the shaded area are used, such as R, B, G.
Since the dots are printed with two colors of ink, the color also becomes dark. Then, in order to make Bk (black) in the shaded portion dark like the portion other than the shaded portion, the pattern (D) is printed. As shown in FIG. 4, this pattern (D) indicates that O prints only Bk ink, and Y,
M and C indicate that the Y, M, and C inks are printed on the Bk ink, respectively. This color mixing is performed for each dot from the first line to the fourth line. As a result, the shaded area becomes an array pattern of 4 colors of Bk, Bk + Y, Bk + M, Bk + C, and the one with a fine dot density becomes dark to the human eye due to the effect of subtractive color mixing shown in FIG. The contrast goes up.

In this way, Y, M, C shown in FIG. 1 are arranged in one pattern or a color matrix arranged so as not to have a specific color tone, so that Y, M, C are displayed on the dots displaying black.
Since the ink of Bk and the ink of Bk are printed on top of each other, Bk (black) is emphasized and the contrast of the entire image can be increased.

In the above embodiment, the color mixing is shown as an example according to a fixed pattern, but the colors may be randomly changed to perform the color mixing.

<Effects of the Invention> As is clear from the above, the printing method of the present invention is such that the color order of the color inks to be printed by superimposing on the black ink in at least the one-dimensional direction is such that the black display does not have a specific tone. , And the repeating unit of this set color order is expressed by a matrix with dots as elements, and when printing black dots, the color ink of the color selected according to the color order of the above matrix is used. Since the printing is performed by superimposing it on the black ink, the black display can be made darker and the color contrast can be improved even if the black ink having a single density that does not clog the printer head is used.

Further, it is possible to prevent the black display by the printed black dots from having a specific color tone.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a color matrix in an embodiment of a printing method of the present invention, FIG. 2 is a diagram showing a mixed state of inks when red and black are alternately printed in the above embodiment, and FIG. Is a diagram showing a landscape image for explaining the case where the above embodiment is applied to a continuous black area, and FIG. 4 is a diagram showing a color mixing pattern when the above embodiment is applied to the landscape image, FIG. Is a diagram for explaining subtractive color mixing, and FIG. 6 is a diagram for explaining a conventional printing method.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyoshi Kayoshi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Sharp Corporation (56) References JP-A-60-253550 (JP, A) JP-A-SHO 60-174651 (JP, A)

Claims (1)

(57) [Claims] 1. A printing method for expressing a color by a plurality of color inks and a black ink of a single density, wherein at least one-dimensional direction of the color ink to be printed by superposing the black ink on a plurality of dots to be displayed in black. The color order of is set to an order that black display does not have a specific color tone, and the repeating unit of this set color order is expressed as a matrix with dots as elements, and when printing black dots, A printing method, characterized in that a color ink of a color selected according to the color order of the matrix is superimposed on the black ink for printing.