JPS5838180A - Heat-sensitive transfer recorder - Google Patents

Abstract

PURPOSE:To maintain the stable quality of recordings in spite of the variation of temperature by a method in which the temperature of ink layer coated on a base film is detected and according to the detected value, a thermal head is controlled in an ink film regeneration type heat-sensitive transfer recorder. CONSTITUTION:A base film 2 recorded is coated with ink by a roll 9 and then the temperature is detected by a temperature detector 20, e.g., thermister, etc. On the basis of the voltage of temperature detection signal a sent out of the temperature detector 20, pulse width control signal (b) is output from a monostable multi-vibrator 15 is controlled. For example, when the temperature of the ink layer 3 is higher than a standard value, the resistance of the thermister 20 is lowered, the voltage of detection signal a becomes smaller, and thereby such a signal (b) that the pulse width of pulse signal (e) becomes smaller is sent forth and the time of electrification to a heating element 27 becomes shorter than a given value. On the contrary, when the temperature of the ink layer 3 is lower than a standard value, the time of electrification to the heating element 27 becomes longer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer recording device used in printers, facsimile machines, etc. In particular, the present invention relates to a thermal transfer recording device that is used in printers, facsimile machines, etc. This relates to a recording device.

Recently, thermal recording devices have been widely applied to printers, facsimile machines, etc. due to their simplicity, low cost, and high reliability. However, there were major problems with the preservation and falsification of records.

As an apparatus for solving this problem, a thermal transfer recording apparatus as shown in FIG. 1 is known.

That is, in FIG. 1, a heat-fusible ink layer 3 is provided on a base film 2 to form an ink film 11. The ink layer 3 is selectively heated and melted from the base film 2 side by the thermal brush 1 and transferred onto the recording paper 4 pressed by the platen roll 5.

Such a device solves the above-mentioned problems of storage stability and falsification in the conventional thermal recording device. However, if the ink film consisting of the base film and the ink layer is made disposable, the cost of consumables increases, resulting in a problem of high running costs.

As a device for solving this problem, a device is known that regenerates the ink film and uses it repeatedly, as shown in FIG.

FIG. 2 is a schematic cross-sectional view of an ink film regeneration type thermal transfer recording device. In the figure, the same reference numerals as in FIG. 1 represent the same or equivalent parts.

Reference numeral 6 denotes an ink application roll immersed in the ink 17 in the ink tank Z, and a drive roll for the 8#i ink film 11. 9 is a coating counter roll arranged to face the ink coating roll 6 and sandwich and press the ink film 11 therebetween.

The base film 2 is formed into an endless belt shape, and an ink tank 7 is applied onto the base film 2 by the ink application roll 6.
The ink 17 inside is applied.

After selective recording and transfer onto the recording paper 4 by the thermal head 1, the base film 2! /c, the ink 17 is applied again by the ink application roll 6.

Therefore, the ink layer 3Fi is constantly regenerated and the base film 2Fi is used repeatedly.

Therefore, in such an apparatus, the base film 2 does not become a consumable item, and only the ink used for recording is consumed, so that the cost of consumable items becomes extremely low.

In the thermal transfer recording apparatus as described above, ink is applied to the base film in a heated state, and the base film heated by the thermal head is used repeatedly.

The temperature of the applied ink layer varies depending on conditions such as the rounding, the temperature of the ink application roll, the proportion of the Pt part of the base film heated by the thermal spatula, and the ambient temperature.

Such fluctuations in the ink layer temperature before recording result in fluctuations in recording density. That is, when the ink layer temperature is higher than the reference value, less recording energy is required to melt a predetermined amount of ink.

Nevertheless, assuming that a constant recording energy is always applied, the recording energy supplied to the thermal head in excess of the required amount will melt more than a predetermined amount of ink, which will reduce the recording density. The disadvantage was that it was expensive.

On the other hand, when the ink layer temperature is lower than the reference value, there is a drawback that the density becomes low.

The purpose of the present invention is to prevent the temperature of the applied ink layer from fluctuating depending on various conditions such as the temperature of the ink application roll, the proportion of the dot portion of the base film heated by the thermal stub, and the ambient temperature. Another object of the present invention is to provide a thermal transfer recording device in which recording quality such as recording density is kept stable.

In order to achieve the above object, the present invention detects the temperature of the ink layer after being applied to the base film at a position before recording is performed by the thermal head, and adjusts the temperature of the ink layer according to the detected temperature. The feature is that the recording conditions of the head are controlled.

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 5 is a schematic cross-sectional view of one embodiment of the present invention.

In the figure, the same reference numerals as in FIG. 2 represent the same or equivalent parts. A temperature detector 20 is brought into contact with the back surface of the base film 2 and indirectly detects the degree of temperature of the layer 6 applied by the roll 9 via the base film 2. For example, a thermistor is used for this purpose.

FIG. 4 is a block diagram showing the configuration of the control device 30 shown in FIG. In the figure, the same reference numerals as in FIG. 3 represent the same parts.

12 is a function generator to which the temperature detection signal a outputted from the temperature detector 20 is input, and outputs a pulse width control signal S based on the voltage of the temperature detection signal a; 13Fi;
This is an N-digit shift register into which a recording signal C is continuously input and stored, and is converted into a parallel recording signal g.

14 is a predetermined amount (N digits) in the N digit shift register 13.
The N-ary counter 15 outputs the trigger signal d when the recording signal C is input and stored, and when the pulse width control signal outputted from the function generator 12 is input, the N-ary counter
This is a monostaple multivibrator which receives the signal d and outputs the pulse signal e.

Reference numeral 16 denotes an AMIn"- to which the parallel recording signal g outputted from the previous shift register 13 and the pulse signal e outputted from the monostaple multivibrator 15 are input, and outputs an output signal f for each dot. ), 18 is a current drive circuit that supplies a recording current to the heating element 27 of the thermal head P1 in accordance with the output signal f output from the A N Ill'' -) 16.

In the thermal transfer recording apparatus having the above-mentioned configuration, when controlling the recording conditions of the thermal head in accordance with fluctuations in the temperature of the ink layer, the following procedure is performed.

For example, when the temperature of the ink 113 is higher than the reference value, the resistance of the thermistor used as the temperature detector 20 decreases by the amount of the temperature higher than the reference value. Therefore, the voltage of the temperature detection signal a output from the function generator 124C decreases in inverse proportion to the temperature of the ink layer 3.

Based on the magnitude of the voltage of the temperature detection signal a, the output of the pulse width control signal S output from the function generator 12 is determined.

On the other hand, when a predetermined amount (N digits) of the recording signal C is input and stored in the one-digit shift register 13, the advance counter 14 outputs the tri-signal d. When the signal d output from the N-ary counter 14 is input to the mono-staple multivibrator 15, the mono-staple multivibrator 15 outputs a pulse signal θ.

Since the pulse width control signal S controls the time constant of the monostaple multivibrator 15, as described above, when the temperature of the ink layer 3 is higher than the reference value, the pulse width of the pulse signal U is increased by the higher temperature. The width becomes smaller than the predetermined width.

The pulse signal θ outputted from the mono-staple multivibrator 15 and the parallel recording signal g outputted from the N-digit shift register 13 are inputted to the MDR 16. The output signal is output.

According to the output signal f issued from the ND date 16,
A recording current flows through the current drive circuit 18 to the heating element 27 of the thermal head 1 .

As is clear, the time for energizing the heating element 27 is as follows:
The pulse width is the same as that of the pulse signal e outputted from the mono-staple multivibrator 15.

When the recording current as described above flows through the thermal head 1, the ink layer 3 is heated and melted, and recording is performed on the paper 4.

As described above, when the temperature of the ink layer 3 is higher than the reference value, the time for energizing the heating element 27 is shorter than the predetermined value.

On the other hand, when the ink layer 6 is lower than the reference value, the time during which the heating element 27 is energized becomes longer.

In the experiments conducted by the present inventors, 1
A 2.5 μm curly film was used, the thickness of 11472 layers was 6 μm, the feeding speed was 40 wm/sθC, and the thermal head was 8 dots/-.
The ink layer was heated with an average resistance value of 300Ω and an applied power of α8 W/Yt.

Under the above conditions, when the ink layer temperature (base film temperature) is 30℃, the current application time is 1 m5ec, and when the ink layer temperature (base film temperature) is 20℃
, 4m5ec, and 40°C, Q and 8meec were set, respectively, and the experiment was conducted by changing the ambient temperature from 5°C to 30' (3).

As a result, the recording density was (1,1±α2), with very little variation, and stable quality was obtained over a long period of time.

As is clear from the figure, in the present invention, there is a Kid shift between the position of the ink layer where the temperature is detected and the position of the ink layer where recording is performed by thermal spacing.

However, the recording point - i.e. the position of the thermal head
The temperature of the ink layer at lK is a function of the temperature at the measurement point, and the functional relationship can be known in advance. Therefore, if the input/output characteristics of the 1-function generator 120 are set according to the functional relationship, the deviation can be virtually completely corrected.

In the above, a thermistor was used as the temperature detector 20, but it goes without saying that a thermocouple, an infrared detector, etc. may also be used. Further, although the temperature of the ink layer is indirectly detected from the temperature of the back surface of the base film, the temperature of the surface of the ink layer may be directly detected.

Although the time during which electricity is applied to the heating element is controlled as a recording condition for the thermal head, the applied current (applied voltage) may be controlled as long as the applied energy can be controlled.

As described above, the present invention detects the temperature of the ink layer after being coated on the base film at a position before recording is performed by the thermal head, and moves the thermal spatula P according to the detected temperature. Since the recording conditions are controlled, even if various conditions such as the ambient temperature, the temperature of the ink coating roll, and the proportion of dots on the Real Base Film heated by the thermal head change, the density will remain stable with little change. This has the advantage that high recording quality can be obtained over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a partial schematic cross-sectional view of a thermal transfer recording device, FIG. 2 is a schematic cross-sectional view of an ink film recycling type thermal transfer recording device, FIG. 3 is a schematic cross-sectional view of an embodiment of the present invention, and FIG. is a Pronk diagram of the control device of FIG. 3; 1... Thermal head, 2... Base film, 3
... Ink layer, 6... Ink coating roll, 12...
・Function generator, 13...N-digit shift register, 14・
... N-ary counter, 15 ... Mono staple multivibrator, 16 ... AND date, 20.1. thermistor

Claims (1)

[Claims] (1) A base film that runs in the form of an endless belt, an ink applying means that applies ink that is solid at room temperature and melts when heated over the entire surface of the base film, and a recording signal from the back side of the base film. In a thermal transfer recording apparatus, the thermal transfer recording apparatus includes a heat application means that selectively heats the ink according to the temperature of the ink layer formed on the surface of the base film, and transfers the molten ink to a recording paper that is brought into contact with the ink layer formed on the surface of the base film. A temperature sensor and a means for controlling the electrical energy supplied to the heat application means according to the temperature of the ink layer detected by the temperature sensor. Thermal transfer recording device.