JPH03290270A - Color printer - Google Patents

Abstract

PURPOSE:To obtain stable picture quality comparatively easily regardless of medias to be used without enlarging a memory by a method wherein recording characteristics of a media to be a reference are stored in a memory, and when other media is used, energy to be added to the recording system is controlled in response to the media. CONSTITUTION:A power connection waveform is changed for each media unrelatedly from a tone. The title color printer is equipped with a means to generate pulse signals and a means to count the pulse number, and a peak value or ON time for the pulse signals is made variable. By doing these, energy added to a head can be easily changed. Also, by dividing the pulse number by a fixed rate for each tone, time to add energy to the head can be changed. Also, data to be stored in the memory is only the dividing rate, and peak values of the pulse signals corresponding therewith or ON time, and it does not cause enlargement of the memory.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color printer that can handle various media, and particularly to a color printer suitable for sublimation thermal transfer recording.

[Conventional technology]

In general, in color printers that overlap multiple colors, recording characteristics also change if different media, such as recording paper or ink film, are used. The color reproducibility of a color image is determined by the overlapping ratio of multiple colors. Conventional color printers have only one type of halftone control circuit, as shown in Japanese Patent Publication No. 59-17954.

In other words, there is only one type of overlapping ratio of multiple colors, and if the media used changes, the color reproducibility will deteriorate.
There was a problem that a good color pudding 1 was not necessarily obtained. In addition, in the full-color printer described in Japanese Patent Application Laid-Open No. 63-74665, the overlapping ratio of multiple colors is stored in memory for normal paper and for plastic film such as HP sheet. It is stored in. However, in such a method, the overlapping ratio must be stored in memory for each number of media, resulting in an increase in memory size and a problem of poor flexibility.

[Problem to be solved by the invention]

The conventional technique described above does not take into consideration the use of many types of media, and has the problem that a constant image quality cannot be obtained regardless of the mezzo 3-4-ear used.

An object of the present invention is to provide a color printer that relatively easily provides stable image quality regardless of the media used, without increasing the size of the memory.

[Means to solve the problem]

In order to achieve the above object, in claims 1 to 3 of the present invention, the energization waveform is changed for each medium (irrespective of the gradation).

In claim 4 of the present invention, in order to achieve the above object, only one type of standard recording characteristic is stored in memory, and the recording characteristic is corrected according to the medium to be used.

In claim 5 of the present invention, in order to achieve the above object, data compression is performed and all recording characteristics of each medium are stored in memory.

[Effect]

According to claims 1 to 3 of the present invention, the device includes means for generating a pulse signal and means for counting the number of pulses, and the peak value or ON time of the pulse signal is made variable. Thereby, the energy (average) applied to the head can be easily changed. Further, by dividing the number of pulses into a fixed ratio for each gradation, it is possible to change the time for applying energy to the head. Moreover, the data to be stored is only the division ratio and the peak value or ON time of the pulse signal corresponding to each of the division ratios, so that the memory does not become larger.

Claim 4 of the present invention. As for claim 5, since a level comparator is provided and the level is set according to the medium, it is possible to apply energy according to the medium without increasing the size of the memory.

〔Example〕 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a thermal transfer color printer employing an embodiment of the present invention. With traditional printers,
Converts the input image signal 1 into a digital signal and converts it into an RA
The amount of ink of the three primary colors yellow, magenta, and cyan (or four colors including black) necessary for reproducing the colors of the manually supplied image is derived by the gradation control circuit 3. Here, energy is applied to the head in order to deposit the required amount of ink onto the recording paper (obtain the required recording density). At this time, if the media such as recording paper or ink film is changed, the required density cannot be obtained unless the amount of energy applied to the head is changed. −
An example is shown in FIG. By the way, the energy to be applied is determined by the voltage and the energization time. In general, the voltage is assumed to be constant,
Controls the energization time. As a specific method, in the pulse generation circuit 6, the pulse width (both period and ON time) is constant, and the number of pulses is stored in the gradation ROM 4. In other words, the gradation ROM 4 stores a table as shown in FIG. This is 12
8 gradations, yellow and magenta.

This is a case where four colors of cyan and black are used, and the number of data to be stored is 128 (gradation) x 4 (color) = 512
It is. Further, since it is a thermal recording, the characteristics change depending on the temperature of the head, and temperature compensation is essential to prevent deterioration of image quality.

For example, if the control is divided into ten stages depending on the temperature of the head, 128X4X16 (stages) = 8192
data will be stored in the gradation ROM 4.

Furthermore, if the relationship between the gradation and the number of pulses is to be stored in memory for each medium, the number of media would be 128x4x16x [number of media], which would lead to an increase in memory size and poor flexibility.

In one embodiment of the present invention, the above problem is solved by changing the energization waveform (strobe signal) to the head for each medium, regardless of the gradation. First of all,
In FIG. 1, data is stored in the gradation ROM 4 in the conventional manner.

In other words, only one type of recording characteristic is stored. Next, a case will be described in which one line is printed at a period of a (ms). For example, the 50th tone of yellow is
Suppose that a density of 0.5 is required.

When using the media (1), as shown in FIG. 4(a), it is assumed that the required concentration can be obtained by applying current for b (ms) at a voltage of 1. As mentioned earlier, count the pulse signals with the same period of several μs (fourth
Figure (b)), energizes only for b (ms). Here, the value of vl can be changed by changing the ON/OFF ratio of the pulse signal. Conventionally, this ON/OFF ratio was constant, and the V mechanism was always constant. In addition, it is theoretically possible to store voltage data in the one-gradation ROM 4 and to keep the energization time constant. In the present invention, the data in the dynamic ROM 4 is the same as before, and the ON/OFF ratio of the pulse signal is changed. By doing so, an energization waveform as shown in FIG. 4(c) can be obtained. By changing the energization waveform in this way, the temperature on the surface of the thermal head takes on a waveform as shown in FIG. Naturally, the temperature at which color starts to develop and the temperature at which image quality begins to deteriorate when heated vary depending on the recording paper, ink film, etc. Therefore, with conventional color printers, when the media is changed, not only is it not possible to obtain good color reproducibility, but the image quality deteriorates, such as the power axis missing in low-density areas or abnormal transfer in high-density areas. There was also. In the present invention, as shown in FIG. 5, the energization waveform can be made to match the coloring characteristics of the media, so the above-mentioned problem does not occur. Next, a method for changing the electromagnetic waveform in this way will be described. In the circuit diagram shown in Figure 1, the power RO
Everything other than M5 is the same as the conventional one. For example, a table as shown in FIG. 6 is stored in the power ROM 5.

First, in Fig. 4, the ONN time (ms) of the energization waveform
Divide into several parts and memorize the ratio of the division. Next, information for changing the peak value V1 of the energization waveform is stored in memory. Specifically, the value of 1 can be changed by lengthening or shortening the ON time of each pulse signal. More specifically, a method for changing the value of 1 will be explained with reference to FIGS. 7 and 8.

FIG. 7 is a block diagram of the pulse generation circuit 6, and FIG. 8 is a block diagram of the pulse generation circuit 6.
It is a timing chart of each signal. The data in the power ROM 5 is transferred to a counter 8. in the pulse generation circuit 6. The output Q of the RS flip-flop 10 is counted by the counter 9.
is one pulse signal. That is, the ON/OFF ratio of this pulse signal can be changed by the data in the power ROM 5. Therefore, for example, a programmable counter can also be used. The above explained the case of changing the ○N time of the pulse signal, but
The same applies when changing the peak value.

In other words, (1) in FIG. 4 is changed depending on the peak value of each pulse signal. This specific method is easy if, for example, a programmable power supply is used. The table in the power ROM 5 shown in FIG. 6(a) is as follows:
This is an example in which the ON part of the energization waveform (the part to which pulses are applied) is divided into two and the ON time number of the pulse signal is changed. In this case, the number of data may be [number of media] x three. Of course, even if it is the peak value of the pulse signal that is being changed,
Even if the division is finely divided (for example, Fig. 6 (b)),
Since the energization waveform is changed independently of each gradation, the memory capacity does not increase dramatically. Therefore, compared to the case where recording characteristics are stored in memory for each medium, a much smaller memory is required and it is possible to handle many types of media. Although the gradation ROM 4 and the power ROM 5 are shown separately in FIG. 1, one ROM is of course sufficient. In addition, one type (or several types) of standard recording characteristics are memorized,
As shown in FIG. 9, it can also be translated in parallel in the vertical and horizontal directions. Inside the memory, there are standard recording characteristics and a vertical axis according to each media.

It is sufficient to memorize the shift amount in the horizontal axis direction. Furthermore, as another embodiment, the reference recording characteristics may be rotated as shown in FIG. Further, as shown in FIG. 11, the recording characteristics may be stored in memory for all media by linearly approximating some or all of the recording characteristics and compressing the data. In either case, a sensor inside the printer may recognize which media to print on and automatically select the memory, or it may be selected manually by switching an external switch. . 1st
FIG. 2 is a perspective view of the latter printer.

Further, a method of automatically selecting a mark using a sensor can be easily carried out by, for example, detecting a mark on the back side of the recording paper and selecting the memory contents corresponding to the mark, as shown in FIG. In either case, color prints with good color reproducibility can be made regardless of the media.

〔Effect of the invention〕

According to the present invention, since the energization waveform is changed for each medium, stable image quality can be obtained regardless of the medium. Furthermore, since the energizing waveform is changed regardless of the gradation, the memory size is not increased compared to the case where recording characteristics are stored in memory for each medium.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of differences in recording characteristics depending on media, and FIG. 3 is an explanatory diagram of memory contents in a gradation ROM of an embodiment of the present invention. Fourth
The figure is an energization waveform diagram, FIG. 5 is a temperature waveform diagram on the head surface when the energization waveform is changed, FIG. 6 is an explanatory diagram of the memory contents in the power ROM of one embodiment of the present invention, and FIG. 7 is a block diagram of the pulse generation circuit, FIG. 8 is a timing chart of each signal, FIGS. 9 to 11 are explanatory diagrams of other embodiments of the present invention, and FIG. 12 is an embodiment of the present invention. FIG. 13, which is a perspective view of the printer shown in FIG. 1, is a detailed explanatory diagram of the present invention. DESCRIPTION OF SYMBOLS 1... Image signal, 2... RAM, 3... Halftone circuit, 4-gradation ROM, 5... Power ROM, 6... Pulse generation circuit, 7... Head drive device, 8 ...Counter, 9...Kaya! Hard moth hard floor kunju grass (nori, ○2 bolt ← 5 Chronoff ■ ■ Iichi ■ Tokara > ri 8 Karantade Yokun Autumn potato 0 Meka no 3 <(1-) 0ri 7

Claims (1)

[Claims] 1. Superimpose multiple colors on selected media,
Among the recording characteristics that differ depending on the media used in a color printer that performs code copying of color images, there are the following:
A color printer characterized in that the recording characteristics of the medium serving as a reference are stored in memory, and when using another medium, the energy applied to the recording system is controlled according to the medium. 2. A color printer according to claim 1, comprising the memory storing recording characteristics and the memory storing energy to be applied to the recording system, and combining them depending on the medium to be used. 3. In claim 1 or 2, energy is applied to the thermal head, recording is performed by the heat generated, the relationship between each gradation and the energization time is memorized, the energization time is divided into a plurality of parts, and the energization time is divided into a plurality of parts. A color printer that is provided with means for changing the energy applied to each. 4. In claim 1 or 2, the pulse signal is provided with a means for generating a pulse signal and a means for counting the number of pulses, the relationship between each gradation and the number of pulses is memorized, and the pulse signal is Control the peak value or number of pulses,
A color printer that divides the number of pulses into a plurality of pulses and changes the peak value of the pulse signal or the ON time of the pulse signal for each divided pulse, thereby changing the average energy applied to the head. 5. In claim 1, 3 or 4, one or several types of recording characteristics, such as the relationship between each gradation and the number of pulses or each gradation and energization time, are stored in memory, and depending on the media used, parallel movement, rotation, etc. A color printer that corrects recording characteristics by performing the following steps. 6. The color printer according to claim 1, 3 or 4, wherein recording characteristics are stored in memory for each medium, and data is compressed by linear approximation in portions that are relatively close to straight lines. 7. The color printer according to claim 1, 2, 3, 4, 5 or 6, comprising means for allowing a user to select recording characteristics depending on the medium to be used. 8. Claims 1, 2, 3, 4, 5, or 6, wherein recording paper among the media used is provided with means for detecting marks made on the back side and means for recording according to the detected marks. color printer.