JPH09109565A - Thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively read a detection mark provided on a heat transfer sheet corresponding to the change of the conveying speed of the sheet with small influence of the mounting regulation and sensitivity regulation of a read sensor. SOLUTION: A first detection mark 20 is provided at a first coloring material layer of a coloring material layer group and second detection marks 30, 40, 50 are provided at the second and following coloring material layers in the thermal transfer sheet 1 formed on a base material that the coloring material layer group of at least three or more coloring material layers are formed plurality of repeatedly on the base material, and the width (d) of the lengthwise direction of the sheet 1 of the mark 20 is formed longer than that of the lengthwise direction of the second mark 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color thermal transfer sheet, and more particularly to a thermal transfer sheet used in a color printer for obtaining a multicolor color hard copy based on image information such as a still image of a color TV.

[0002]

DISCLOSURE OF THE INVENTION According to the present invention, a detection mark formed on a thermal transfer sheet is less affected by attachment adjustment of a reading sensor and sensitivity adjustment, and is erroneously read even by a change in conveyance speed of the thermal transfer sheet. An object of the present invention is to provide a thermal transfer sheet having a non-existent detection mark.

[0003]

In order to solve the above problems, the present invention provides a thermal transfer in which a plurality of color material layer groups each composed of a color material layer of at least three colors are repeatedly formed on a substrate. In the sheet, a first detection mark is provided on the first color material layer of the color material layer group, and a second detection mark is provided on each of the second and subsequent color material layers. The thermal transfer sheet is composed of one mark whose longitudinal width is longer than the longitudinal width of the second detection mark. Further, in the thermal transfer sheet, the second detection mark is composed of an assembly of a plurality of small marks, and the width of the small mark in the longitudinal direction is shorter than the width of the first detection mark in the longitudinal direction.

[0004]

2. Description of the Related Art As a method for forming an image by a thermal transfer method, a thermal transfer sheet having a base material sheet provided with a dye layer containing a sublimable dye in a binder is heated by a thermal head based on an image information signal. There is a sublimation type thermal recording system in which recording is performed by sublimating (transferring heat) the dye in the dye layer. Also known is a heat-sensitive melting type recording method using a heat transfer sheet provided with a heat melting ink layer in which a coloring material such as a pigment is contained in wax instead of the dye layer.

In a thermal transfer sheet, a coloring material layer such as a dye layer or a hot-melt ink layer, which is separately coated in yellow, magenta, and cyan, is usually formed on a base sheet. Therefore, in order to print these colors by superimposing them with the thermal head, it is necessary to accurately convey the color material layers of the respective colors to the printing start position. For this purpose, the printer must recognize the color of the color material layer of the thermal transfer sheet, and a thermal transfer sheet provided with a detection mark corresponding to each color material layer is used. As a form of such a detection mark, a mark in which the number of the marks is changed corresponding to each color of the color material layer is often used in order to identify each color of the color material layers which are separately applied.

However, the detection mark of the conventional thermal transfer sheet is output from the sensor after reading the mark when the adjustment of the mounting position, angle, or sensor sensitivity of the sensor for reading the mark on the printer is insufficient. Is not stable and the difference in the number of marks may not be recognized normally. In addition, the number of marks cannot be accurately recognized due to instability of the transfer speed of the thermal transfer sheet when the winding torque of the thermal transfer sheet is insufficient, or instability of the transfer speed due to changes in the amount of winding of the thermal transfer sheet, etc. There is. Further, the number of marks may not be recognized due to a slight difference in density that occurs when a mark is printed on the thermal transfer sheet, a shift in the slitter position during cutting of the thermal transfer sheet, and the like. Then, there is a problem that such a reading error of the detection mark causes a color shift in the color printing.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a thermal transfer sheet of the present invention, in which a first color material layer Y of yellow, a color material layer M of magenta, and a color material layer C of cyan. A plurality of color material layer groups each including a black color material layer BK are repeatedly provided. Regarding one set of color material layer groups, the first detection mark 20 is provided on the color material layer of the first color, and the second detection marks 30, 40, 50 are provided on the other color material layers, respectively. The width d of the first detection mark 20 in the longitudinal direction of the thermal transfer sheet is longer than the width e of the second detection marks 30, 40 and 50 in the same direction. Although the first color is yellow here, the first color in the present invention means the color material layer to be printed first, and it may be any color of cyan and magenta depending on the printing method. .

Next, in the printing method using the thermal transfer sheet 1, before the first color yellow color material layer of the thermal transfer sheet is conveyed to the position of the thermal head, a reading sensor provided in the printer is used. Detection mark 2 of the same color material layer
0 is detected, the thermal transfer sheet is further conveyed by a predetermined amount, and the printing start positioning of the first color yellow is performed.
Subsequently, the dye of the same color material layer is transferred onto the image receiving sheet by heating the thermal head.

When a transmission type sensor is used, the detection mark is detected by detecting a change in the transmittance between the mark and the color material layer as a change in voltage while the thermal transfer sheet is being conveyed, and the transmittance is remarkably high. The lowered portion is judged as a mark. In the case of the thermal transfer sheet 1, while the thermal transfer sheet is being fed, the presence of the mark is first detected due to the change in the transmittance, and further the thermal transfer sheet is continuously fed to detect the low transmittance. When the distance is the width d, it is determined that the detection mark of the yellow color material layer has been detected, the conveyance of the thermal transfer sheet is stopped, and the positioning of the yellow color material layer of the first color is completed. Then, the image receiving paper and the thermal transfer sheet are contacted with each other and pressure-bonded between the thermal head and the platen roller, and the thermal head is heated according to desired image information to form a yellow image on the image receiving paper. The distance of the width d of the mark 20 read by the sensor is determined by the number of pulses of the pulse motor for winding the thermal transfer sheet and the rotary encoder provided on the thermal transfer sheet supply side.

When the printing of the yellow color material layer approaches the end or by continuing to convey the thermal transfer sheet, the detection mark 30 of the magenta color material layer of the next color is detected, and the transmittance is detected low. When the state is a distance e smaller than the distance d of the detection mark 20, it is determined that the mark of the magenta color material layer is detected, and the conveyance of the thermal transfer sheet is stopped. Then, return the image receiving paper on which the yellow printing is completed to the printing start position, and again press the color material layer of the thermal transfer sheet and the image receiving paper between the thermal head and the platen roller to convey the magenta image. To start.

Next, when the detection mark 40 provided on the cyan color material layer is detected in the same manner as the detection mark 30, the conveyance of the thermal transfer sheet is stopped, the image receiving paper is returned to the printing start position, and the thermal head and the platen are again placed. The cyan printing is started while the cyan color material layer of the thermal transfer sheet and the image receiving paper on which the yellow and magenta printings have been completed are pressed into contact with the roller and conveyed. Similarly, print black,
When the transfer of the thermal transfer sheet is stopped and the printing of the image of one screen is completed when the yellow mark of the next color material layer group is detected, the yellow printing start positioning is also performed. The distance of the width e of the second mark to be detected is determined by the same method as that for the first mark.

The first color material layer of the first color in the present invention
If the ratio of the width of the detection mark of 1 to the width of the second detection mark provided on the other color material layers after the second color is 2: 1,
Even if the transfer speed of the thermal transfer sheet changes due to some misalignment of the printer, the mark can be accurately detected. The shape of the detection mark is preferably a rectangle or a square in which the widths of both the first and second detection marks are constant. FIG. 2 shows a detection mark 3 in which the second detection mark is composed of two small marks having a width f shorter than the width d of the first detection mark.
It is the thermal transfer sheet 2 of the example which comprised 1, 41, 51.
In the detection of the second detection mark in this case, the second detection mark is detected when the state in which the transmittance is detected low is f twice, which is a distance smaller than the distance d of the width d of the detection mark 20. Is determined. The second detection mark of this shape is
The reading accuracy is higher than that of one mark.

The location where the detection mark is formed may be a non-printing area of the color material layer, for example, a location where printing by a thermal head on the color material layer is not performed like the thermal transfer sheets 1 and 2, When the coloring material layer is applied to the central portion of the base material film of the thermal transfer sheet, it can be directly formed on the end portion of the base material film having no coloring material layer. Such a detection mark is preferably one that can be optically read by a transmissive sensor, a reflective sensor, or the like, and ink composed of a dye or pigment and a binder can be formed on the thermal transfer sheet by a conventional printing means such as gravure printing. it can.
Further, when a transmissive sensor is used, it is read by the difference in transmissivity between the detection mark part and the color material layer or the mark part and the base film, but the transmissivity is preferably 5% or less.

The detection mark of the present invention is a thermal transfer sheet for sublimation transfer recording comprising a dye layer made of a resin binder containing a sublimable dye on a plastic film substrate such as a polyester film, or on a substrate. It can be applied to a heat-sensitive melting type thermal transfer sheet provided with a heat-sensitive melting type ink layer containing a pigment in wax or the like. Also,
It can also be applied to a thermal transfer sheet in which a dye layer and a heat-sensitive melt ink layer are separately coated on the same substrate. As the thermal transfer sheet, a sheet provided with a heat resistant slipping layer, which is a conventional means for improving sliding with a thermal head, a sheet provided with a primer layer between a dye layer and a substrate, and the like can be naturally used.

[0015]

EFFECT OF THE INVENTION The thermal transfer sheet of the present invention has a width of the first detection mark of the color material layer of the first color and a length of the width of the second detection mark of each color material layer of the second and subsequent colors. Since the detection mark of can be detected, adjustment of the sensor,
It is possible to reliably position each color material layer and prevent color misregistration in color printing without erroneous recognition due to a change in the transfer speed of the thermal transfer sheet or a density difference generated during mark printing.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a thermal transfer sheet of the present invention.

FIG. 2 is a plan view showing another embodiment of the thermal transfer sheet of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Thermal transfer sheet of 1st Example 2 Thermal transfer sheet of 2nd Example 20 1st detection mark 30, 40, 50 of 1st color 2nd detection mark 31, 41, 51 2nd comprised with a small mark Detection mark of d d Width of first detection mark e, f Width of second detection mark

Claims (2)

[Claims] 1. A thermal transfer sheet comprising a color material layer group consisting of at least three or more color material layers formed on a substrate by repeating a plurality of color material layer groups, wherein the first color material layer of the color material layer group is the color material layer. Is provided with a first detection mark, and each color material layer of the second and subsequent colors is provided with a second detection mark. The width of the first detection mark in the longitudinal direction of the thermal transfer sheet is the length of the second detection mark. A thermal transfer sheet comprising one mark longer than the width in the direction. 2. The second detection mark is composed of an assembly of a plurality of small marks, and the width in the longitudinal direction of the small mark is shorter than the width in the longitudinal direction of the first detection mark. Item 1. A thermal transfer sheet according to item 1.