JPS63203368A - Thermal transfer type color printer - Google Patents

Abstract

PURPOSE:To markedly enhance reproducibility of colors, by individually controlling the energization time for a thermal head at the time of transferring in each of colors Y, M, C. CONSTITUTION:Predetermined printing in a color Y is conducted by feeding a paper by one dot pitch on printing in each line. Before transferring in a color M, the duration of printing pulses is increased as compared with that in transferring in the color Y. Before transferring in a color C, the duration is increased as compared with those in transferring in the color Y and in the color M. Finally, a paper is fed to a position for positioning the head of the next page, thereby completing color printing of one page. Thus, the energization time is individually controlled for each of the colors in consideration of transfer characteristics associated with ink materials for the colors Y, M, C and the order of transferring, so that printing in each of the colors can be uniformly performed, whereby reproducibility of the colors is markedly enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer color printer (melting type thermal transfer color printer) used as an output device for word processors, computers, etc.

[Prior Art] Traditionally, this type of thermal transfer color printer has used three primary colors: yellow (yellow, hereinafter simply referred to as rY color), magenta (red or crimson, hereinafter simply referred to as "M color").
That's what it means. ), cyan (blue).

Hereinafter, it will simply be referred to as ``10 colors''. There is a method that prints, for example, seven colors using the swing method using the principle of subtractive color mixing by superimposing ().

A conceptual diagram of the structure of such a thermal transfer color printer is shown in FIG. In FIG. 6, reference numeral 1 denotes a color transfer ribbon coated with heat-melting seven-color ink, M-color ink, and C-color ink repeatedly in the longitudinal direction. By driving the motor M1, the paper is sent out from the supply roller 2, passes through the printing section 3, and is taken up by the take-up roller 4. Further, 5 is a transfer sheet (plain paper), 6 is a thermal head, and 7 is a platen roller. The thermal head 6 is provided with a heat generating cell (not shown) that generates heat when energized. During printing, the thermal head 6 is urged toward the platen roller 7 to press the color transfer ribbon 1 and the transfer paper 5 together, and the heating cells generate heat to melt the ink applied to the color transfer ribbon 1. The image is then transferred onto the transfer paper 5. Note that Pl is a pulley that drives the platen roller 7.

Next, a case will be described in which color printing is performed in the apparatus shown in FIG. 6. First, the color transfer ribbon winding motor M1 is activated by power input, and the color transfer ribbon 1 is guided to the starting position of Y color. The Y color start position is detected by detecting a black mark printed on the color transfer ribbon 1 using a reflective optical sensor. M,C
The cue for each color is distinguished by a black mark different from the Y color and detected by the same optical sensor. Further, a constant torque clutch is directly connected to the winding motor M1 of the color transfer ribbon 1, so that the color transfer ribbon 1 is wound with a constant torque in response to changes in the winding speed due to changes in the print speed and changes in the winding diameter. .

Next, the paper 5 is rewound by a certain amount in response to a copy command. This operation is performed in order to reduce the margin that occurs between the paper cutting position and the position of the thermal head 6 and to make effective use of the paper 5.
This has the meaning of ensuring dot overlay accuracy for M and C colors (see operation flow F1 in FIG. 7).

Next, the paper 5 and the color transfer ribbon 1 pass through a thermal head 6 while being pressed against a platen roller 7 . At this time, since one pulse of the pulse motor driving the platen roller 7 corresponds to one dot pitch in the sub-scanning direction, a predetermined Y color print is performed while feeding one dot pitch for each line print (7th (See operation flow F2 in the figure).

Next, at the thermal head 6, since the paper 5 and the color transfer ribbon 1 are adhered by ink, overfeeding is performed to peel them off (see operation flow F3 in FIG. 7).

Next, the paper 5 is rewound to the start position, and at the same time the color transfer ribbon 1 is rewound to the start position of M color (
(See operation flow F4 in FIG. 7).

Thereafter, the M color and the 0 color are printed in the same manner as the Y color (see operation flow F5 to F9 in FIG. 7).

Paper 5 is then fed to the beginning position of the next page (
(See operation flow FIO in FIG. 7).

Color printing of one screen is completed by the above operations.

[Problems to be Solved by the Invention] However, in such conventional thermal transfer color printers, each color of Y, M, and C is printed with the same energy.

Due to minute differences in the ink characteristics of each C color and differences in transfer order, there are problems in that M color is more difficult to transfer than Y color, and 0 color is more difficult to be transferred than M color. When attempting to obtain black by superimposing M and C colors, the resulting black color becomes reddish, resulting in poor color reproducibility.

The present invention was made to solve these problems, and when transferring each color of Y, M, and C, it is possible to improve the reproducibility of each color by individually controlling the energization time to the thermal head. The purpose of the present invention is to provide a thermal transfer color printer that is capable of doing the following.

[Means for solving problems] For this reason, the thermal transfer color printer of the present invention.

Next, an ink color detection means for detecting whether the ink to be melted is yellow ink, red ink or blue ink is provided, and when the ink detected by the ink color detection means is red ink or blue ink, An energization control means is provided for making the energization time to the thermal head longer than that for yellow ink.

[Function] In the thermal transfer type color printer of the present invention described above, the ink color detection means detects whether the ink to be melted and transferred next is one of the seven 2M colors or C color ink, and if M
When it is detected that it is color ink or C color ink,
The energization control means makes the energization time to the thermal head longer than when using Y color ink.

[Embodiments of the Invention] The present invention will be specifically described below with reference to illustrated embodiments. Figures 1 to 5 show a thermal transfer color printer as an embodiment of the present invention. Figure 1 is a block diagram of its main parts, Figure 2 is a block diagram showing its overall configuration, and Figure 3 is its main part block diagram. A flowchart for explaining the action, and FIGS. 4 and 5 are both waveform diagrams for explaining the action.

In this embodiment as well, as shown in the structural conceptual diagram in FIG. 6 and the operational flow diagram in FIG. A heat pattern is applied via the thermal head 6 to the color transfer ribbon 1 on which ink) has been applied repeatedly in the longitudinal direction, and Y, M, and C colors are applied to the color transfer ribbon 1 according to the heat pattern. By sequentially melting each of the Y, M, and C color inks in this order, these melted inks are transferred onto the transfer paper 5 as a transfer paper superimposed on the color transfer ribbon 1. It is now possible to print in color.

By the way, as shown in FIGS. 1 and 2, a reflective optical sensor 9 detects a black mark printed on the color transfer ribbon 1.
is provided in the feeding path of the color transfer ribbon 1, and upon receiving the detection signal from this optical sensor 9, the next ink to be melted is the Y color ink.

An ink color detection means 16 is provided for detecting whether the ink is M color ink or C color ink.

Also, a thermistor 8 that detects the temperature of the thermal head 6
The output of the thermistor 8 is converted into temperature data (digital data) by the temperature detection circuit 10 and then supplied to the energization control means 17 of the control section 11 .

The energization control means 17 sends the printing pulse P to the head drive circuit 15.
The pulse width setting means 18 is provided to change and set the width of the print pulse P based on the temperature data from the temperature detection circuit 10.

That is, this pulse width setting means 18 is connected to the thermal head 6.
When the temperature of the thermal head 6 is low, the pulse width of the printing pulse P is widened, while when the temperature of the thermal head 6 rises, the pulse width is narrowed as the temperature rises. Further, this pulse N setting means 18 is activated when the temperature of the thermal head 6 abnormally rises.
When the temperature exceeds a predetermined limit temperature, the time during which the printing pulse P is turned off (hereinafter referred to as pulse off time) is lengthened. Examples of printing pulses P when the thermal head 6 is in various temperature states are shown in FIGS. 4(a) to 4(a).
(d). That is, as long as the temperature of the thermal head 6 is low, the width of the printing pulse P is large as shown by the symbol τ0 in FIG. 4(a), and as the temperature of the thermal head 6 becomes high, The code τ1. The width of the printing pulse P becomes narrower as shown by τ2. Note that the pulse off time T is set in order to prevent the printing speed from decreasing until the temperature of the thermal head 6 rises abnormally.

is constant. In this way, by gradually narrowing the pulse width of the printing pulse P, the heat generation time of the heat generating cells is shortened, and it is possible to prevent the thermal head 6 from overheating.

When the temperature of the thermal head 6 rises abnormally, the pulse off time is lengthened as indicated by the symbol T1 in FIG. 4(d).

Thereby, heating of the thermal head 6 can be prevented.

Further, the energization control means 17 has a pulse width changing means 19. This pulse width changing means 19 receives the output from the pulse width setting means 18 and the output from the ink color detecting means 16, and does not change the width of the printing pulse P when the ink to be transferred next is Y color ink. However, if the ink to be transferred next is M color ink, the width of the print pulse P is increased by, for example, 30% at most, and if the ink to be transferred next is C color ink, the width of the print pulse P is increased. For example, it increases by about 40% at most. As a result, when the next ink to be transferred is M color ink or 0 color ink, the time for energizing the thermal head 6 is made longer than when the ink is Y color ink. When the thermal head 6 is in a certain temperature state, examples of printing pulses P output when transferring ink of each color of Y, M, and C are shown in FIG. 5 (
a).

(b) and (c). That is, if Fig. 5(a) is the case when M color ink is transferred, Fig. 5(b) is the case when M color ink is transferred, and Fig. 5(c) is the case when C color ink is transferred. It is something. And, Fig. 5(a) to (c)
In, t2-Y is the current application time (pulse width) during M color ink transfer, and τ2-M is the current application time (pulse width) during M color ink transfer.

τ2-C is the energization time (pulse width) during C color ink transfer, and TO is the pulse off time.

Note that the printing pulse width amplification ratio can be changed as appropriate depending on the temperature of the thermal head 6, etc.

Additionally, this color printer is equipped with a motor drive circuit 12 that drives the platen roller motor 13.
The motor drive circuit 12 drives a step motor (pulse motor) 13 under the control of the control section 11 to rotate the platen roller 7 by a minute angle.

Further, 14 is a print data memory, which stores dot data supplied from an external computer or the like. This stored dot data is read out by the address signal ADH supplied from the control section 11 and supplied to the head drive circuit 15.

The head drive circuit 15 causes the thermal head 6 to generate heat based on the dot data supplied from the print data memory 14, and is composed of the same number of registers and gate circuits as the heat generating cells of the thermal head 6, and drives the dot data to these. It is stored in a plurality of registers and the control unit 11
When a printing pulse P is supplied from the print head 6, electricity is applied to a specific heat generating cell of the thermal head 6 to generate heat based on the stored dot data. In this case, the energization time of one heating cell and the pulse width of the printing pulse P are equal.

With the above-described configuration, when the power is turned on, the color transfer ribbon take-up motor M1 operates, and the color transfer ribbon 1 is guided to the start position of Y color. This Y color start position detection is performed by detecting a black mark printed on the color transfer ribbon 1 using a reflective optical sensor 9. The cue for each of the M and C colors is distinguished by a black mark different from the Y color and detected by the optical sensor 9.

Next, the paper 5 is rewound by a certain amount in response to a copy command. As mentioned above, this operation is performed to reduce the margin between the paper cutting position and the position of the thermal head 6, thereby making effective use of the paper 5, and to ensure dot overlay accuracy for each color of Y, M, and C. (See step a1 in Figure 3)
.

Next, the paper 5 and the color transfer ribbon 1 pass through a thermal head 6 while being pressed against a platen roller 7 . At this time, the pulse motor 1 driving the platen roller 7
Since one pulse of No. 3 corresponds to one dot pitch in the sub-scanning direction, the predetermined seven colors are printed while advancing one dot pitch for each line printing (see step a2 in FIG. 3).

Next, at the thermal head 6, since the paper 5 and the color transfer ribbon 1 are adhered by ink, overfeeding is performed to peel them off (see step a3 in FIG. 3).

Next, the paper 5 is rewound to the start position, and at the same time the color transfer ribbon 1 is rewound to the start position of M color (
(See step a4 in FIG. 3).

At this time, the width (current application time) of the printing pulse P is controlled according to the temperature state of the thermal head 6, as shown in FIGS. 4(a) to 4(d).

Hereinafter, steps a6 to a8 and step al in FIG.
As shown in o and all, the M and 0 colors are printed in the same way as the Y color, but before the M color transfer, the printing pulse width is increased compared to the Y color transfer (
(See step a5 in FIG. 3), and then set the printing pulse width to Y before C color transfer.

The amount is increased compared to the M color transfer (see step a9 in FIG. 3).

Finally, the paper 5 is fed to the beginning position of the next page (see step all in FIG. 3), and color printing of one screen is completed.

In this way, the energization time is controlled individually according to each color, taking into account the transfer characteristics of the ink materials and transfer order of each color of Y, M, and C, making it possible to print uniformly for each color. This greatly improves color reproducibility.

In addition, when performing C color transfer after M color transfer.

The pulse width during M color transfer may be maintained. In this case, the process of step a9 in FIG. 3 is omitted.

[Effects of the Invention] As detailed above, according to the thermal transfer color printer of the present invention, when transferring each color of Y, M, and C, the time of energization to the thermal head is individually controlled. The advantage is that reproducibility can be significantly improved.

[Brief explanation of the drawing]

1 to 5 show a thermal transfer color printer as an embodiment of the present invention, and FIG. 1 is a block diagram of its main parts;
FIG. 2 is a block diagram showing its overall configuration, FIG. 3 is a flow chart for explaining its operation, FIGS. 4 and 5 are waveform diagrams for explaining its operation, and FIG.
FIG. 7 shows a conventional thermal transfer color printer, FIG. 6 is a conceptual diagram of its structure, and FIG. 7 is a schematic diagram for explaining its operation. In the figure, 1-color transfer ribbon, 5-transfer paper (paper), 6-thermal head, 7-platen roller, 8-
Thermistor, 9-light sensor, 101 temperature detection circuit, 11
- control unit, 12 - motor drive circuit, 13 - step motor, 14 - print data memory, 15 - head drive circuit, 16 - ink color detection means, 17 - energization control means,
18-pulse width setting means, 19-pulse width changing means. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A color transfer ribbon is coated with heat-melting yellow ink, red ink, and blue ink repeatedly in the longitudinal direction.
A thermal pattern is applied to the yellow ink, red ink and blue ink applied to the color transfer ribbon by applying a thermal pattern to the color transfer ribbon according to the thermal pattern.
In a thermal transfer color printer that performs color printing by sequentially melting red ink and blue ink and transferring these melted inks onto the transfer paper superimposed on the color transfer ribbon, the next step is to An ink color detection means for detecting whether the ink to be melted is yellow ink, red ink or blue ink, and when the ink detected by the ink color detection means is red ink or blue ink, A thermal transfer type color printer, characterized in that it is provided with an energization control means that makes the energization time to the thermal head longer than that for yellow ink.