JPS61291188A - Gradation printing method and ink sheet therefor - Google Patents

Abstract

PURPOSE:To provide a novel printing method and an ink sheet for use in the method which ensure easy processing of signals and favorable gradation properties, by constituting one printing cycle of several printing operations and performing overlap printing by several printing operations at the same printing position to the thereby produce gradations, in a thermal transfer printing method wherein printing is conducted by melting an ink by heating. CONSTITUTION:Inks 221, 222, 223 are transferred onto a recording paper 40 by the first, the second and the third printing operation, respectively. One printing cycle is constituted of the three printing operations. A high density is produced by overlap printing consisting of all of the three printing operations, and a lower density is produced by a smaller number of printing operations used for overlap printing, whereby gradation properties are provided.

Description

[Detailed description of the invention]! TECHNICAL FIELD The present invention relates to a gradation printing method suitable for use in a thermal transfer type or thermal color printing type copying machine, and an ink sheet therefor.゛Prior art - Figure 8 is a diagram showing the main parts of an example of a thermal transfer recording device. In the figure, 10 is a printing section, 11 is a print head main body, and 12 is a heating element (print heater). , 13 is a print signal source, and as is well known, a large number of heating elements 12 are embedded in the print head main body 11, and the heat generated by each heating element is heated by the print signal from the print signal source 13. It looks like this. 20 is an ink sheet, 30 is a presser roll, 40
is a recording paper, and the ink sheet 20 is made of a base (substrate) 21 and a heat-melting ink layer 22. As is well known, the ink sheet 40 is rotated in the direction of arrow A by rotating the presser roll 30 in the direction of arrow A.
direction, during which the heating element 22 is moved in accordance with the print signal.
The ink on the ink sheet 20 is melted by heating, and the ink is adhered to the recording paper 40 as shown at 22' to form a transferred image.

Note that the melting point of the ink 22 applied to the ink sheet 1 and 20 is usually about 40 to 1(')OT, and sometimes about 1(')OT.
50° (sometimes it is about 2 degrees.The thickness of the ink is 1
After μ~50/Ll'Ii+. Further, although a polyester film is generally used for the base 21, a polyimide film 11 is used when heat resistance is particularly required. The thickness of the base 21 is approximately 1 μm to 30 μm, and is generally as thin as possible.

Therefore, in the thermal transfer as described above, in order to obtain i) η tonality, conventionally, as shown in FIG. 9, (a) the area of one dot shown in FIG. 13 is divided, Example Eve, (b)
As shown by diagonal lines in the figure, only 1/4 of the area of one dot is printed so that it appears as if there are 43 shades of density due to an optical illusion (area gradation), or As shown by the curve in Figure 10, the input terminal that applies the voltage to the heating element is made thicker to produce gradation (
Curve r3 indicates the case where there is no gradation).

However, all of the above conventional gradation methods have drawbacks such as complicated signal processing, complicated equipment, n□ value (l), and heavy load on the thermal print head.

■---- The present invention was made in view of the actual situation of children.
In particular, the present invention has been made with the object of providing a new printing method and ink sheet with simple signal processing and good gradation.

The present invention is directed to a thermal transfer printing method in which printing is performed by melting ink by heating in order to achieve the objective described in the article 1. One printing cycle is achieved by several printing operations. A printing method in which the same printing position is formed by multiple printing operations to produce gradation by multilayer printing, or one printing cycle is formed by several printing operations, and each A printing method in which the printing position is changed for each printing operation, and the amount of ink melted during each printing operation is changed to produce gradation.
Alternatively, a plurality of layers having different ink content sizes are repeated in the moving direction, and the plurality of layers are divided into one printing cycle and 1:3.
- It features the Inksy 1-. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is an enlarged view of a printed part printed by the printing method according to the present invention, and in the figure, 30 is a recording paper 221, 222.
．． 223 indicates the ink transferred to the removed paper 30-H, 221 indicates the ink printed by the first printing operation, 222 indicates the second printing operation, and 223 indicates the ink printed by the third printing operation. In the case of the illustrated example, one printing cycle consists of three printing operations, and when the density is high, all three printing operations perform overlapping printing, and as the density becomes lighter, the number of overlapping is reduced. It is designed to give gradation.

Is Figure 2 a superimposed copy of the Juki? This is an enlarged view for explaining a modified example of A. In this embodiment, as shown in the figure, the printing area at the second printing operation 222 is changed from the printing area 222 at the first printing operation.
It is smaller than the printing area in 1, and the area ratio is 9.
8% or less, preferably 95% or less. By doing this, it is possible to prevent synchronization between the first and second mark printing, and also to prevent the head from being The input voltage or current can be made smaller or the current application time can be made shorter than that during the first impression, thereby making it possible to make the heating star in the head smaller.

FIG. 73 is an enlarged side view for explaining an example of the ink droplet 1~ used in another printing method of the present invention.
In the figure, 20 is an ink sheet, 21 is a base, 22 Q
, 22b, 22c, the ink layer has three layer parts of 22cl, 22b, and 220 layers (wire number), and when the ink sheet 2o moves in the direction of arrow A, "F] + "F2 +... is one printing cycle, and in each printing cycle, Inksey I
. . . by shifting ~ little by little to perform a printing operation that prints a single layer portion of only 22a, a printing operation that prints a two layer portion of 22a and 22b, and a printing operation that prints a three layer portion of 22a, 22b, and 22c. By doing so, the areas where the first layer is printed are printed lightly, and the areas where the three layers are printed are printed darkly, so that gradation can be obtained. Note that it is also possible to print using the printing method shown in Figures 1 and 2 using the ink sheet shown in Figure 3, and by doing so, even finer gradation can be obtained. can. However, in this case, it is not necessary to shift uniformly,
22b and 22c may be arbitrarily selected. Also,
It is easily understood that a heat-sensitive coloring sheet 1 may be used in place of the heat-sensitive transfer sheet J, and the coloring may be caused by applying electricity to the heat-sensitive sheet. In addition, in the case of this energization method, the ink portion or the entire ink sheet 20 has a resistance of 106Ω (1
) The conductivity may be as follows. Moreover, although the case where the ink color is one color has been described above, the present invention is also applicable to printing not only with one color but also with two or more colors.

FIG. 4 shows a three-color ink sheet 20 consisting of red (R), yellow (Y), and blue (R), and using such an ink sheet, the ink sheet 20 as described in connection with FIGS. 1 and 2 is printed. Depending on the printing method, overlapping printing may result in printing with gradation.

5 to 7 are views showing examples of ink sheets for multicolor mixed printing, respectively. The ink sheet 1- shown in FIG. r R
2) An example of providing an ink layer with one layer of yellow (Y) on the top layer, and the ink sheet shown in Figure 6 has one layer of red (R1) on the bottom layer.
, -1 is an example in which two layers of yellow (Yi + Y2) ink layers are provided, but the color tone is sufficient in either case, and there is almost no difference. Moreover, FIG. 7 shows a continuous sheet with a red ink layer (R).

It is composed of a blue ink layer (B) and a yellow ink layer (Y).

Effects As is clear from the above explanation, according to the present invention, signal processing is not complicated as in area gradation or general gradation in the prior art, and therefore the device is simplified and the load on the head is reduced. Become. In particular, as shown by curve B in the case of general gradation, if there is no gradation or the number of gradations is reduced, input is reduced, and damage to the head or blurring of print due to overheating can be prevented. Further, there are advantages such as the possibility of various combinations of color tones and gradations.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of a printed portion printed by the overlap printing method according to the present invention, FIG. 2 is an enlarged view for explaining a modification of the -1: overlap printing method, and FIG. 4 is an enlarged side sectional view for explaining an example of an ink sheet suitable for use in another printing method of the present invention, and FIG.
) and blue (B), FIGS. 5 to 7 are diagrams showing examples of ink sheets for multicolor mixed printing, and FIG. FIGS. 9 and 10, which are main part configuration diagrams for explaining an example of a thermal transfer type recording apparatus, are diagrams for explaining a conventional area gradation printing method and a general gradation printing method. 10...Printing section, 11...Print head body, 12...
- Heating element, 13... Print signal source, 2o... Ink sheet, 30... Presser roll, 40... Recording paper. Patent applicant: Ricoh Co., Ltd. 8 = Figure 1 Figure 2 Figure 3 C omitted -- Figure 4 Figure 5 Figure 6, Y2 Figure 7 Figure 8 Figure 9 (CI) (b) Figure 10 figure

Claims (3)

[Claims] (1) In a thermal transfer or thermal color printing method in which ink is melted by heating and printed, one printing cycle is formed by several printing operations, and the same printing position is printed several times. A gradation printing method characterized in that gradation is produced by multilayer printing using the printing operation. (2) In thermal transfer or thermal color printing methods in which ink is melted by heating and printed, one printing cycle is formed by several printing operations, and each printing operation A gradation printing method characterized by changing the printing position and changing the amount of ink melted during each printing operation to produce gradations. (3) A gradation ink sheet characterized in that it has a plurality of layers having different ink contents repeatedly in the moving direction, and the plurality of layers correspond to one printing cycle.