JP3093483B2 - Thermal transfer printer and ink sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printer,
In particular, the present invention relates to a mechanism for locating ink in a thermal transfer printer using a multi-ink sheet and an improvement of an ink sheet.

[0002]

2. Description of the Related Art A conventional thermal transfer printer includes an ink sheet that is conveyed in a predetermined direction at a predetermined speed by an ink sheet take-up roll or the like and an image receiving sheet that is wound around a platen roller and conveyed in the same direction at a predetermined speed. The ink information and the image receiving sheet are superposed, sandwiched between a platen roller and a thermal head that generates a heat pattern according to the image recording information, and the image information is transferred onto the image receiving sheet by selectively transferring the ink of the ink sheet. Is transferred to In a color thermal transfer printer, an ink sheet in which ink regions of cyan, magenta, yellow and the like are alternately arranged in the longitudinal direction is used, so that desired colors are transferred in a desired order. For this purpose, it is necessary to search for the ink area of each color.

For example, Japanese Patent Application Laid-Open No. Sho 62-212249 discloses a cue method for such a color thermal transfer printer in which a light-transmitting pattern is formed along each boundary line of each ink region (light absorbing portion) on an ink ribbon. And a light-transmitting pattern and a light-absorbing portion are detected by using a reflective photosensor disposed at a position corresponding to a movement path of the pattern and a light-reflecting object disposed opposite to the photosensor with a ribbon interposed therebetween. A method for cueing the ink ribbon is disclosed, but among the ink regions constituting the light absorbing portion, for example, a yellow ink region absorbs a B (blue) light component while R (red) is absorbed. Since light and G (green) light are transmitted respectively, the yellow region cannot be used as the light absorbing portion unless light source light having only the B (blue) light component is used. It is not possible to perform an accurate cueing. For the same reason, the light absorbing section can be used for the first time by using the G light source for the magenta ink and the R light source for the cyan ink. Therefore, it has been difficult to perform accurate cueing with the above-described prior art in which only one color of light is used.

In order to solve such a problem, a color sensor (a red, green, and blue filter is attached, respectively) for detecting an ink color area as disclosed in Japanese Patent Application Laid-Open No. 60-96473. Needs to be used to compare the output currents from the three photodiodes), but the color sensor is not only complicated and expensive, but also uses a filter to increase the light amount of the light source more than usual. It is necessary to increase the heat generation amount and the installation space.

In the above-described conventional printing method (hereinafter referred to as a one-time method) in which an ink sheet is conveyed at the same speed as an image receiving sheet, transfer is performed using an ink sheet having the same length as the transfer length of the image receiving sheet. Since the amount of the color ink on the ink sheet base was small, it was thin, and all the ink areas transmitted light from the sensor, and it was not possible to directly detect the presence or absence of ink on each ink area. . For this reason, conventionally, a color material (black or white) for light absorption or light reflection has been applied to an appropriate position as a mark for tip detection separately from the ink area. However, since colors other than the three colors used for printing are used for marks, there is a problem that the manufacturing cost of the ink sheet increases.

[0006]

As described above, in the color ink sheet used in the conventional one-time type thermal transfer printer, it is difficult to detect the color because the amount of ink forming the ink area is small. However, the present invention has a disadvantage that the cost is increased when formed, but the present invention can simultaneously solve the drawbacks common to such one-time type printers and the drawbacks of the individual techniques described in the above publication. It is intended to provide a printer.

[0007]

According to a first aspect of the present invention, there is provided an ink sheet in which a plurality of color ink regions are alternately and repeatedly arranged along a conveying direction at a speed equal to a conveying speed of an image receiving sheet. / N (n> 1) in a thermal transfer printer, a first driving unit for rotating and driving a shaft for winding up the ink sheet, and a second driving unit for driving a supply side shaft for feeding the ink sheet. Wherein the second driving means determines the ink sheet transport speed during printing.

[0008]

The present invention will be described below with reference to an embodiment shown in the accompanying drawings. In the thermal transfer printer according to the embodiment of the present invention, the ink sheet is used at high density by setting the speed ratio between the ink sheet conveyance speed and the image receiving sheet conveyance speed to 1: n (n> 1). This is a multi-printing type printer that saves its consumption, reduces the frequency of replacement and suppresses running costs.
The ink has been applied thickly to allow for multiple transfers. Therefore, if an infrared or red light emitting LED is used as an optical sensor for cueing the ink regions of yellow, magenta, and cyan, the portion where the cyan ink is applied blocks light. Therefore, if this cyan ink is used as the head mark of the ink area of each color, it is not necessary to form a mark in a color other than the above three colors, and the manufacturing cost of the ink sheet can be reduced.

[0010] Figure 1 Yellow, magenta, color areas Y consisting of cyan, M, the light by the top mark 2,3,4 consisting cyan paint border region 1 located between C respectively arranged The sensor can identify each top mark, and the ink sheet can be positioned accurately.
It is a structural example. In this ink sheet, one cyan mark at a different position is used as a head mark 2 of a yellow area Y and a head mark 3 of an adjacent magenta area M, and two cyan marks are used as a head mark 4 of a cyan area C. Color marks were used. The ink on the ink sheet is transferred by sublimation or melting by heat generated by a thermal head used in a printing unit of a thermal transfer printer.

FIG. 2 is a diagram showing the transmittance of each color of yellow, magenta, and cyan, and shows a state where the transmittance of cyan decreases in a wavelength region corresponding to red or infrared light. FIG. 3 shows that when the detection light of the optical sensor 5 composed of a red or infrared light emitting diode is applied to the head marks 2, 3, and 4 on the ink sheet I, the detection light is received by the light receiving element 5b.
This indicates a state in which an H (high) signal is output to a control unit (not shown) in order not to return to. When the detection light irradiates a portion other than the cyan mark and the cyan area C, the detection light passes through the ink sheet and is reflected by the reflector 6 to be reflected by the light receiving element 5b.
Incident on. At this time, an L (low) signal is output to a control unit (not shown). The optical sensor 5 is disposed at a position corresponding to the head marks 2 and 3, and the control unit determines the presence or absence of the head mark and the type of the head mark based on the combination of the presence or absence of the reflected light.

In a multi-printing type thermal transfer printer, color unevenness occurs unless the speed ratio between the image receiving sheet and the ink sheet I is constantly maintained at n: 1 during printing. As shown in (a), it is necessary to continuously rotate the ink sheet supply shaft 10 at a constant speed by using a pulse motor or a servomotor 11. on the other hand,
The winding of the ink sheet I is performed by a motor 14 via a torque limiter 13 on a winding shaft 12 so that the ink sheet is not loosened. Since the ink sheet supply side is driven at a constant speed in this way, if the change in the diameter of the sheet wound on the supply shaft 10 is reliably absorbed, the head of yellow, which is the color to be printed first, can be used. Only the output is performed, and the subsequent color determination can be realized by counting the number of pulses of the pulse motor or the number of encoder pulses of the servo motor. FIG. 4B shows an example of the configuration of the ink sheet I used in the embodiment of FIG. 4A. The boundary area 1 is provided only immediately before the yellow area Y, and the number of marks and the number of sensors for detecting the marks are one by one. Is fine.

Next, when printing in a panoramic size in which the length in the conveying direction is about twice the standard size, the conveying speed of the ink sheet is set to about 1/2 of that in the standard size. The ink sheet transport speed can be reduced by changing the speed of the pulse motor 11 that drives the supply shaft 10. Each color area Y on the ink sheet I,
When performing the cueing of M and C, it is not necessary to convey the ink sheet at a constant speed.
Then, high-speed conveyance may be performed only by the winding motor 14.

Even if a head mark is not formed on the ink sheet I, if a green light emitting LED is used as an optical sensor, the detection light is transmitted in the yellow area Y, and the light is blocked in the magenta and cyan areas M and C. For this reason, the point in time when the detection light from the optical sensor changes from “blocking” to “transmission” can be determined as the head position of the yellow area.
Further, when the color changes from “transmission” to “blocking”, it can be determined that the color is next to yellow (magenta in FIG. 4A). FIG. 5 shows an example in which a yellow area Y is detected using a green light-emitting LED, and shows a state in which detection light transmitted through the yellow area is reflected by the reflector 6 and reaches the light receiving element 5b. . The last color, cyan, may be detected by counting the number of pulses of the supply motor. At this time, the thickness of the ink and the sensor sensitivity are adjusted so that the detection light applied to the yellow ink is transmitted and the detection light applied to the magenta and cyan areas is absorbed and cut off.

[0015]

As described above, according to the present invention, in addition to the motor for winding the ink sheet, a motor capable of constant speed control is used as a drive source for the ink sheet supply shaft. The ink sheet can be conveyed to prevent the occurrence of density unevenness, and the ink sheet is conveyed at a constant speed. As a result, the head of the first ink area of the color ink areas sequentially arranged on the ink sheet is determined. For example, it is possible to determine the head of other subsequent color regions by counting the pulses of the supply-side motor.

[0016]

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the configuration of an ink sheet.

FIG. 2 is a diagram showing transmittance of each color of yellow, magenta, and cyan.

Shows a detection mechanism for the FIG. 3 is a top test knowledge.

4 (a) and (b) is a diagram showing a configuration explanatory view and a configuration example of an ink sheet used in the present onset Ming sheet feeding mechanism.

FIG. 5 is an explanatory diagram of a configuration of another mechanism for detecting a head .

[Explanation of symbols]

I Ink sheet 1 Boundary area 2, 3, 4 First mark 5 Optical sensor 5a Light emitting element 5b Light receiving element 6 Reflector 10 Supply axis 11 Pulse motor or servo motor as first drive means 12 Winding axis 13 Torque limiter 14 Hoisting motor as first driving means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-97884 (JP, A) JP-A-1-244880 (JP, A) JP-A-3-164286 (JP, A) JP-A-3- 178472 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 17/06 B41J 2/325 B41J 17/36 B41J 35/16

Claims (1)

(57) [Claims] 1. A thermal transfer printer for conveying an ink sheet in which ink areas of a plurality of colors are alternately and repeatedly arranged along a conveying direction at a conveying speed of 1 / n (n> 1) of a conveying speed of an image receiving sheet. A first drive unit for rotating and driving a shaft for winding the sheet; and a second drive unit for driving a supply-side shaft for sending out the ink sheet. A thermal transfer printer characterized in that: