JP2000037962A - Multiple layer ink ribbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a high density printing in a short period of time, without performing a superposed printing a plurality of times, and make a low density printing having less roughness by a method wherein a first ink of which the melting temperature is relatively high is applied on a thin film, and on the first ink, a second ink of which the melting temperature is relatively low, is applied in a manner to be superposed. SOLUTION: In this multiple layer ink ribbon 1, on a thin film 1-1 of PET or the like, a plurality of color inks of yellow, magenta and cyan of a high density are applied under a specified arrangement in the order of the surface, as a first coating layer 1-2. The melting points of the melting inks are set in the vicinity of a temperature which is close to the limit at the time of the production of the melting. Then, a second coating layer 1-3 is set in a manner to become the same color arrangement for the plurality of colors of the first coating layer 1-2, and melting inks of yellow, magenta and cyan of a low density are applied on the first coating layer 1-2 in a manner to be superposed. The density of the second coating layer 1-3 is set at an approx. one half of the density of the first coating layer 1-2, and the melting point of the second coating layer 1-3 is set lower than the melting point of the first coating layer 1-2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink ribbon used in a thermal transfer printing apparatus for performing color printing by thermal transfer printing.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. Hei 6 (1986) -2861 discloses a method for performing thermal transfer printing using heat generated by a thermal head.
There is one disclosed in JP-A-81. FIG. 2 is a perspective view showing a configuration of an ink ribbon used in the conventional printing apparatus. This conventional ink ribbon 1 has a thin film 1-1.
A plurality of meltable inks of yellow, magenta, and cyan are applied as a first coating layer 1-2 face-to-face.

In the thermal transfer printing apparatus, the first coating layer 1-2 of the ink ribbon 1 and the recording paper are pressed by a platen roller and a thermal head, and the amount of heat generated is controlled by energizing a heating resistor of the thermal head. In this way, the amount of ink melted is controlled, and color multi-tone printing is performed by transferring the ink. In order to perform multi-tone printing satisfactorily, as disclosed in the publication, a method is employed in which the print pixel arrangement is staggered or a porous recording medium is used for recording paper.

[0004]

However, when multi-gradation thermal transfer printing is to be performed using this conventional ink ribbon, if high-density transfer printing is to be realized, the ink applied to the ink ribbon must have a high density. Need to be However, when using the ink ribbon coated with the high-density ink, it was difficult to express a low-density region. When expressing low density, high density ink is transferred to small area recording paper by the area gradation method, but due to the high density of the transferred ink, it is easy to see even small area and printed. The resulting image is rough and causes deterioration in image quality. In addition, when the density of the ink to be applied is low, a high density cannot be obtained, and a contrivance such as performing multiple printing multiple times is required. For this reason, there is a problem that it is difficult to print multi-gradation recording from low density to high density in a short time and without deteriorating the image quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and enables high-density printing in a short time and low-density printing with less roughness without performing multiple printings. The purpose is to obtain a simple ink ribbon.

[0006]

Means for Solving the Problems The present invention has been made in view of the above-mentioned problems, and the invention according to claim 1 is directed to applying a first ink having a relatively high melting temperature onto a thin film film. And a second ink having a relatively low melting temperature, which is applied over the first ink. "

According to a second aspect of the present invention, there is provided an image forming apparatus, wherein: the first ink has a relatively low density with respect to the second ink;
2. The multilayer ink ribbon according to claim 1, wherein the density of the ink is relatively high with respect to the first ink. ”.

[0008]

FIG. 1 shows the relationship between the structure of a multilayer ink ribbon according to an embodiment of the present invention and the melting point and concentration of a fusible ink applied thereto. First, multilayer ink ribbon 1
As shown in FIG. 1A, a thin film 1 such as PET
-1, high-density multicolor inks of yellow, magenta, and cyan are applied as a first coating layer 1-2 face-to-face in a fixed arrangement. The melting point of these fusible inks is set at around 90 ° C., which is close to the limit at the time of production of melting. The reflection optical density at the time of coating is set in the range of about 1 to 2. Next, the second coating layer 1-3 is set to have the same color arrangement as that of the plurality of colors of the first coating layer 1-2, and low-density yellow, magenta, and cyan fusible inks are applied to the first coating layer 1--2. 2 and apply it. The concentration of the second coating layer 1-3 is set to about half the concentration of the first coating layer, and the melting point is set to about 70 ° C. FIG.
(B) shows the relationship between the melting points and the concentrations of the first coating layer and the second coating layer.

FIG. 3 conceptually shows an example of a print dot pattern. In FIGS. 3A and 3B, a portion hatched to the lower right is a transfer portion by the second coating layer 1-3, and a portion hatched to the right is the first coating layer 1.
-2. FIG. 3A shows a case of a print dot pattern in a relatively low density region. Dots D1, D2
Is a state where only the ink of the second coating layer 1-3 is transferred, and is a state where the ink is transferred at a temperature of 70 ° C. or more and less than 90 ° C. by the thermal energy applied by the thermal head. The dots D3 are further supplied with thermal energy from the thermal head, so that the ink transfer area of the second coating layer 1-3 further expands, and the temperature near the center exceeds 90 ° C., and the ink of the first coating layer 1-2 also increases. This shows a slightly transferred state.

FIG. 3B shows a case of a print dot pattern having a relatively high density. The dots D4 to D6 correspond to the case where the thermal energy is further supplied in order to increase the temperature, and both the ink transfer region of the second coating layer 1-3 and the ink transfer region of the first coating layer 1-2 are enlarged. State.

As described above, the low-density areas correspond to the dots D1 to D1.
As in 3, since dots are formed mainly by the low-density ink of the second coating layer 1-3, roughness in the low-density region is prevented. In the high-density area, the low-density ink of the second coating layer 1-3 and the high-density ink of the first coating layer 1-2 are simultaneously transferred like the dots D4 to D6. -3 is transferred around the high-concentration ink of the first coating layer 1-2, so that dots are formed in the order of the recording paper surface, the first coating layer, and the second coating layer, and the density gradient is reduced. It becomes gradual, and the transferred dots are also less noticeable.

FIG. 3C shows the gradation number versus density characteristics. In the case of only the second coating layer 1-3, as shown by the dotted line, the density increases proportionally from low gradation to high gradation. First coating layer 1-
In the case of only 3, the dots start to be transferred from around the middle of the gradation, and the density increases with a steep slope as shown by the two-dot chain line in the figure. Therefore, the transfer of only the low-concentration ink of the second coating layer 1-3 and the first coating layer 1-
By combining the high-density ink of No. 2 with the transfer of the low-density ink of the second coating layer 1-3, the density is harmonized from low gradation to high gradation as shown by the solid line in FIG. Characteristics.

As described above, since the low-density portion has conventionally been formed of high-density, small-area dots, it is easy to see even at a low density, and the attached state of the dots tends to be non-uniform. This problem has been solved by using the multilayer ink ribbon of the present invention, which has been a cause of image quality deterioration. Further, at the intermediate density, the low density and the high density are mixed, so that the dots are not conspicuous, and the gradation expression is smoothed. Furthermore, dots of low density are not noticeable as in the case of using only conventional high-density ink, so that higher-density ink can be used.

The fusible ink used here is a natural wax such as wood wax or beeswax; a petroleum wax such as paraffin wax or microcrystalline wax; a synthetic wax such as oxidized wax, ester wax or low molecular weight polyethylene; Higher fatty acids such as acid, palmitic acid, and stearic acid; higher aliphatic alcohols such as stearyl alcohol and docosanol; esters such as higher fatty acid monoglyceride and fatty acid ester of sucrose; amides such as stearamide and oleylamide; It can be realized by mixing with dyes or pigments such as yellow, magenta, cyan and the like in combination of two or more kinds. Regarding the adjustment of the ink concentration, it goes without saying that the mixing ratio of the dye or the pigment may be appropriately adjusted.

[0015]

As described above, according to the multilayer ink ribbon of the present invention, a stable density change and a high density can be obtained, and high-speed, low-cost, high-quality printing can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a configuration of a multilayer ink ribbon according to an embodiment of the present invention and a melting point and a concentration of applied fusible ink.

FIG. 2 is a perspective view illustrating a configuration of an ink ribbon used in a conventional printing apparatus.

FIG. 3 is a conceptual explanatory diagram of a print dot pattern in printing using the multilayer ink ribbon of the present invention and a diagram showing the number of gradations versus density characteristics.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink ribbon 1-1 Thin film 1-2 First coating layer 1-3 Second coating layer D1-D6 dots

Claims (2)

[Claims] 1. A method according to claim 1, wherein a first ink having a relatively high melting temperature is applied on a thin film, and a second ink having a relatively low melting temperature is applied on the first ink. Multilayer ink ribbon. 2. A method according to claim 1, wherein said first ink has a relatively low density with respect to said second ink, and said second ink has a relatively high density with respect to said first ink. The multilayer ink ribbon according to claim 1, wherein