JPH0659739B2 - Thermal transfer printer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermal transfer printing apparatus.

(Prior Art) Wire printer as a terminal printer (hard copy device)
In addition to the dot type, the ink jet type, etc., a thermal transfer type printing apparatus has been developed as the most promising one. This thermal transfer printing apparatus uses an ink film in which a heat-meltable ink is applied to one surface of a polyester film having a thickness of 5 to 6 μm, for example, and the ink surface on the front side of the ink film is brought into contact with a recording paper and the back surface is lined. By applying a thermal head and passing an electric current through a predetermined heating element of the line thermal head to generate heat, the ink of the ink film at a position corresponding to the heating element is melted and transferred to a recording sheet.

The density that determines the gradation of characters, figures, pictures, etc. printed using such hot-melt ink is determined according to the area of each dot on the recording paper to which the melt ink is transferred. The area is determined according to the time for which the current applied to each heating element is energized.

Further, according to the thermal transfer type printing apparatus as described above, it is possible to perform printing using an ink film in which the heat sublimation ink is applied to one surface of the polyester film.

The density that determines the gradation of a character or the like printed using such a thermal sublimation ink is determined according to the sublimation amount of the thermal sublimation ink, and this sublimation amount is the above-mentioned heating elements. Determined according to the energization time of the current supplied to the.

As such a conventional thermal transfer printing apparatus, there is one shown in Japanese Patent Application No. 60-117996 filed by the present applicant earlier.

(Problems to be Solved by the Invention) By the way, the inks used in the thermal transfer printing apparatus are roughly classified as described above into hot-melt inks and heat-sublimable inks.

These inks transfer the inks onto the recording paper by the heat generated by the heating element as described above to form an image or the like. The transfer principle of each ink is the same, but its characteristics are as shown in the following table. Significantly different.

Since the heat-meltable ink melts and transfers the ink on the transfer paper, it is difficult to control the thickness of the transfer ink, and a halftone is expressed by the transfer area. Further, the thermally sublimable ink is sublimated and transferred by the heat generated by the thermal head, resulting in density modulation.

Therefore, the optimum heat generation pattern (of the thermal head) for both of these is suitable for the heat-melting ink of the heat concentration type, and for the heat sublimable ink, the heat generation pattern of uniformly heating the entire print dot. .

However, if we try to transfer thermal sublimation ink using the same head, for example, a heat concentration type, with these inks, when the high density printing is performed, the transfer paper base melts in the central part of the heating element or the sublimation in the peripheral part is insufficient. Therefore, there is a problem that a phenomenon of insufficient concentration occurs.

(Means for Solving Problems) The present invention has been made in view of the above-mentioned actual circumstances,
An object of the present invention is to provide a thermal transfer type printing apparatus that can perform good halftone expression with the same line thermal head regardless of whether a heat-meltable ink or a heat-sublimable ink is used.

In order to achieve the above object, the present invention has a plurality of heating elements R ₁ , R ₂ , ... Arranged in a line as shown in FIG.
In a thermal transfer type printing apparatus that individually controls the time of each current to be supplied to the printer in accordance with the density, a control counter 1 that generates and outputs a signal corresponding to a preset supplementary heating time.
8 and the value supplied from the control counter, which holds the value indicating the minimum density during the heat-up time, and within a one-line printing time from the minimum density to the value indicating the maximum density after the heat-up time has elapsed. The reference density data including the reference density data during the heat-up time and the input data to be transferred are compared with each other to obtain a plurality of density values for each unit. Means 14 for generating control data indicating a heating element to which an electric current is to be applied among the heating elements in a row
The reference density data is supplied, and the correction data set so that the relationship between the previously recorded recording density and the reference density data becomes a straight line or a predetermined curve is input according to the reference density data. The correction data generating circuit 22 for outputting, the means for supplying the correction data and the control data, and means for supplying a current to the heating element indicated by the control data for a time corresponding to the value of the correction data 16, 17, G ₁ ... Gn, T
_{1 to} Tn, a first state in which all the heating elements indicated by the control data are turned on when the heating element is energized by means for passing a current through the heating element, and among the heating elements indicated by the control data When recording odd-numbered lines, the odd-numbered heating elements R ₁ , R ₃ , ... Are energized, and when recording even-numbered lines, even-numbered heating elements R ₂ , R ₄ ,. (2) energize even-numbered heating elements when energizing even-numbered heating elements when recording
The present invention provides a thermal transfer type printing apparatus characterized in that it is provided with means 24 to 29 for switching between the above states.

(Embodiment) FIG. 1 shows a circuit system diagram of an embodiment of a thermal transfer printing apparatus according to the present invention. The present invention provides a thermal transfer printing apparatus disclosed in Japanese Patent Application No. 60-117996 filed by the present applicant,
In order to solve the above-mentioned problems, a first state in which all heating elements are newly energized and a second state in which heating elements are energized in a staggered arrangement are newly provided.
The means for switching between the above states is provided. In the figure, the line thermal head 6 is composed of n heating elements R _{1 to} Rn formed in a line on a ceramic substrate. The structure of the line thermal head 6 is the same as that of the conventional thermal transfer printing apparatus, and extends in the width direction of the ink film 1 as shown in FIG. 4, for example.

In FIG. 3, an ink film 1 as a transfer paper has a polyester film 2 coated with an ink 3 such as a heat-melting ink or a heat subliming ink in a predetermined thickness. The recording surface of the recording paper 4 is the ink 3 of the ink film 1.
Of the ink film 1 and the ink film 1 is fed in the direction of arrow A by being brought into contact with the surface. A line thermal head 6 is provided so as to face the roller 5, and the ink film 1
Is in contact with the back side of.

The ink 3 of the ink film 1 at a portion of the heating elements R _{1 to} Rn of the line thermal head 6 corresponding to the energized heating element is melted and transferred to the recording sheet 4. After passing through the line thermal head 6, the ink film 1 is guided by a roller 7 and separated from the recording paper 4, and is wound as a used ink film 1a on a take-up spool (not shown). Ink 3 transferred onto the printed recording paper 4a
a remains. For convenience of illustration, the transferred ink 3a
Although shown as having a large area, it actually consists of a collection of small dots.

One dot is formed by one heating element, and the size of the one dot is determined by the value of current passed through the heating element or the energization time. Then, depending on the size of each dot, the shade or gradation of the printed figure or the like is determined.

The present invention is such a thermal transfer type printing apparatus, and will be described by returning to FIG. 1 again.

First, the print pattern changeover switch 28 in the present embodiment.
Will not be short-circuited, that is, the case where printing is performed using the thermally sublimable ink will be described.

The analog video signal supplied from the TV signal generator 8 is converted into a digital signal by the A / D converter 9 and sent to the data recording device 10 for storage. To start printing, a signal as shown in FIG. 2H is supplied to the terminal 25, and the flip-flop circuit 24 can be inverted.

On the other hand, the address counter 11 is supplied with the reference clock signal from the terminal 12 and the start pulse from the terminal 13. The start pulse is a pulse as indicated by a in FIG. 2 (A), and the address counter 11 and the data counter 15 are reset by the start pulse a which comes in at time t ₁ , and the control counter 18 is supplemented. The preset supplemental heat preset value from the heat preset source 20 is loaded and the output of the flip-flop circuit 24 is inverted. This supplementary heat preset value is a value that determines the supplementary heat time, which will be described later, and includes the period of the pulse b shown in FIG. 2B, the voltage applied to the line thermal head 6, the line thermal head 6 and the recording paper 4. It is determined by the pressing force and further the ambient temperature, and is selected to be, for example, about "4". In addition, the supplementary heat time is set to a time when the pixel data for one line is repeatedly read out an integral number of times.

The control counter 18 counts the pulse b shown in FIG. 2 (B) generated from the address counter 11 based on the reference clock, and during the time ΔT for counting the pulse b by the supplementary heat preset value, As shown in FIG. 2 (C), a low level signal c is supplied to the data counter 15 to stop its counting operation. Therefore, the value of the reference density data d shown in FIG. 2 (D) supplied from the data counter 15 to the density data comparison circuit 14 is the reset value “0” during the time ΔT (this is the supplementary heat time),
That is, the value "0" indicating the minimum density white is held. The cycle of the pulse b is selected to be, for example, about 1/10 of the cycle of the output pulse of the conventional address counter.

Here, when the print pattern changeover switch 28 is open, the output of the OR gate 26 is "1" and is supplied to the AND gate 27.

The address counter 11 sends the first address to the data storage device 10 upon receipt of the start pulse a.
The data recording device 10 sends the first data (the first data of the image data from the A / D conversion device 9) corresponding to the first address to the grayscale data comparison circuit 14. The density data comparison circuit 14 uses the first data and reference density data (hereinafter, referred to as the reference density data indicating the minimum density from the data counter 15).
"0" is compared with "second data", and if the first data is larger than the second data "0", the control data "1" is sent to the shift register 16 via the AND gate 27, and the value is small. For example, control data “0” is sent to the shift register 16.

When the processing at the first address is completed in this way, the address counter 11 sequentially sends the addresses 2, 3, ..., N to the data storage device 10, and the data storage device 10 receives the second to nth addresses each time. The first data corresponding to each address is sequentially sent to the grayscale data comparison circuit 14. Here, the first data from the 1st to n-th addresses correspond to the image data printed by the heating elements R _{1 to} Rn of the line thermal head 6, respectively. The grayscale data comparison circuit 14 compares the first data and the second data “0” corresponding to the addresses 2 to n, respectively, and shifts the control data “0” or “1” in the same manner as above. Register 16
Send to. The n-stage shift register 16 sequentially takes in n-bit control data corresponding to each of the 1st to n-th addresses supplied from the grayscale data comparison circuit 14, and sends it to the latch circuit 17.

When the address counter 11 finishes counting the 1st to nth addresses, it sends the data transfer pulse b shown in FIG. 2B to the data counter 15, the latch circuit 17, and the control counter 18. The period Δt of the data transfer pulse b is shortened to about 1/10 of the conventional one. At the same time that the data transfer pulse b is sent, the data counter 15 supplies the heating pulse e shown in FIG. 2 (E) to the address counter 11 and one input terminal of the AND circuit 19 and the AND circuit 21.

On the other hand, a reference clock signal is supplied to the one end of the AND circuit 19 from the terminal 12, and at the same time when the heating pulse e from the data counter 15 comes in, a pulse is output to the shift register 16 and the address counter 11 outputs. 1-n
The n-bit control data corresponding to the address of the second time is transferred from the shift register 16 to the latch circuit 17. When the data transfer pulse b comes in, the latch circuit 17 latches the control data supplied from the shift register 16 and sends it to each one of the input terminals of the gate circuits G _{1 to} Gn.

On the other hand, the address counter 11 is reset by the input of the heating pulse e and sequentially counts 1 to n addresses again, but during the heat-up time ΔT, the address counter 11 keeps the data storage device 10 in the same line. N pieces of the first data are repeatedly read, and the second data is held at “0”, so that the n pieces of the first data for the same one line have the above value “0”. Second data of
The grayscale data comparison circuit 14 repeatedly compares the sizes.

Therefore, the supplementary heat time ΔT is "1" or more in the first data, that is, the heating current is supplied by the power supply voltage + Vcc to only the heating element to be transferred by the first data to supplement the heat. Therefore, the first data of the white level is retained as white and is not transferred, and the rising of the transfer density is optimized by optimizing the supplementary heat preset value for the density one level above white. You can

Thereafter, when the pulse c becomes high level at time t ₂ when the control counter 18 finishes counting the pulse h by the supplementary heat preset value, the data counter 15 starts the counting operation, and the same operation as above is performed for one line. The first incoming pulse b is counted once at time t ₂ after being performed once for the first minute data, and it was “0” until then (FIG. 2 (D)).
The second data shown in is increased from the smallest value to the value "1" indicating the second density.

As a result, the grayscale data comparison circuit 14 sequentially compares the n pieces of the first data for one line and the second data having the value "1" with each other. Even when the second data is "1", the shift register 16, the latch circuit 17, the AND circuit 1
9 and the like perform the same operation as described above, and the gate circuits G _{1 to} G ₁
The latched control data is sent to one of the n input terminals.

On the other hand, the correction tape storage memory 22 is supplied with the second data “0” shown in FIG. 2D, and the correction data is stored in advance so that the recording time and the density have a linear relationship. The corrected data is sent to the pulse generator 23 using the correction table. The pulse generator 23 is at a high level for a predetermined period including the supplementary heating time ΔT in accordance with the incoming correction data, and after this period, the pulse f shown in FIG. It is generated and output to the other input terminal of the AND circuit 21. The AND circuit 21 generates the pulse g shown in FIG. 2 (G) in response to the incoming heating pulse e and pulse f to generate the gate circuits G ₁ to G ₁ .
It is sent to the other input terminal of Gn.

As shown in FIG. 2 (G), the pulse g has a predetermined period including the supplementary heating time ΔT after time t ₁ (that is, the period from time t _{1 to} t ₃ when the second data d is “0”). Has a predetermined pulse width, and after this period, the pulse width gradually decreases in accordance with the data content of the correction data sent from the correction table storage memory 22.

Each of the gate circuits G _{1 to} Gn receives a gate signal obtained by gate-processing the pulse g and the n-bit control data supplied from the latch circuit 17, and outputs the gate signal to the NPN-type transistor T _1.
To Tn are supplied to the respective bases and the switching control is performed. Among the transistors T _{1 to} Tn, current is passed only to the heating element connected to the collector side of the turned-on transistor to generate heat.

Further, after the time t2, the _second data output from the data counter 15 is "0", in synchronization with the pulses b and e.
.., "m" (where m is a value indicating the maximum density), and the grayscale data comparison circuit 14 determines that the control data "1" when the first data is larger than the second data. 1 "
Is output, and if it is equal to or smaller than the second data, the control data “0” is output. The conduction time of the heating current flowing through the heating element changes according to the control data of "0" or "1" and the pulse width of the pulse g, and the gradation recording of the data for one line is performed.

After that, when the next start pulse g comes in, the output of the flip-flop circuit 24 is inverted, but since the print pattern changeover switch 28 is open, the data from the comparison circuit 14 is sent to the shift register without affecting the address counter. 11 and the data counter 15 are reset, and the data counter 15 again sequentially changes the second data as shown in FIG. 2 (D) from time t ₁ onward and performs the same operation as described above. The gradation recording of the first data for the line is performed.

Therefore, in this case, printing is performed at all addresses of each line.

Next, the case where the print pattern switching switch 28 is short-circuited, that is, the case where the hot-melt ink is used will be described.

The output of the flip-flop circuit 24 which inverts every line printing is supplied to the EX-OR gate 29 together with the lowest address output of the address counter 11. For example, when the output of the flip-flop circuit 24 is "1", the EX-OR output is a signal in phase with the output of the address counter 11. This signal is supplied to the AND gate 27, and when the lowest output of the address counter 11 is "1", the print data from the grayscale data comparison circuit 14 is sent to the shift register 16 of the thermal head as it is, and the address counter 11
If the lowest output of is "0", the thermal head is "0"
That is, non-print data is sent. 1 line of data is 0
The start pulse a when sending up to m gradations (Fig. 2)
Thereby, the output of the flip-flop circuit 24 is inverted and the same operation as described above is performed.

Therefore, if the previous line is printed at an odd address, the next line will be printed at an even address.
The print dots are arranged in a staggered arrangement.

In FIG. 1, the switch 28 is used to switch the print pattern. However, this is a notch recess or a recess provided in a part of the transfer paper cartridge, and these notches are provided when the transfer paper cartridge is mounted. It may be switched by detecting such as. Alternatively, a separation mark such as a code may be printed on a part of the cartridge or the transfer paper winding core, the separation mark may be read by an optical sensor, and the signal may be replaced by the switch 28.

As described above, according to the present invention, in the thermal transfer type printing apparatus disclosed in Japanese Patent Application No. 60-117996 filed by the present applicant, the first state of energizing all the heating elements and the energization of the heating elements in a staggered arrangement are provided. Since the means for switching between the second state and the second state is provided, only the heating element to be transferred can be supplemented with heat, optimal density characteristics can be obtained, high image quality of printing can be achieved, and heat Good halftone expression can be achieved by using either the meltable ink or the heat sublimable ink.

Also, the pattern is changed at the time of application, and Japanese Patent Application No. 60-11
Various correction data described in No. 7996, that is, not only the correction data in which the recording time and the density have a linear relationship, but also the correction data in which the recording time and the density become a predetermined curve are switched. You may use together.

(Effect) As is apparent from the above description, according to the present invention, since only the heating element to be transferred is supplemented with heat, the optimum density characteristic can be obtained, and the cycle of the data transfer pulse is shorter than the conventional one. However, the recording time can be shortened, and since the energization time of the heating element is controlled for each density, the printing quality can be improved and the heating element can be energized. Since the means for switching between the state 1 and the second state in which the heating elements are energized in a zigzag arrangement are provided, good halftone expression can be performed using either the hot melt ink or the heat sublimable ink. it can.

[Brief description of drawings]

FIG. 1 is a circuit system diagram showing an embodiment of a thermal transfer printer according to the present invention, FIG. 2 is a signal waveform diagram for explaining the operation of the circuit system shown in FIG. 1, and FIG. 3 is a thermal transfer according to the present invention. It is a schematic perspective view of an example of the principal part of the thermal transfer type printing device to which the pattern printing device can be applied. 6 ... Line thermal head, 10 ... Data storage device, 1
DESCRIPTION OF SYMBOLS 1 ... Address counter, 12 ... Reference clock signal input terminal, 13 ... Start pulse signal input terminal, 14 ... Gray data comparison circuit, 15 ... Data counter, 16 ... Shift register, 17 ... Latch circuit, 18 ... Control counter, 19, 21 ... AND circuit, 20 ... Supplementary heat preset source, 22 ... Correction table storage memory, 23 ... Pulse generator, G _{1 to} Gn ... Gate circuit, R _{1 to} Rn ... Heating element, T
_{1 to} Tn ... Transistor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toshinori Takahashi, 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Japan Victor Company of Japan, Ltd. (72) Hiroki Kitamura 3--12, Moriya-cho, Kanagawa-ku, Yokohama Address inside Victor Company of Japan (72) Inventor Tadao Shinya 3-12 Moriya-cho, Kanagawa-ku, Yokohama-shi Kanagawa Prefecture Inside Victor Company of Japan (72) Yutaka Mizoguchi 3-12 Moriya-cho, Kanagawa-ku, Yokohama-shi Address Examiner at Victor Company of Japan, Ltd. Toshihisa Saito (56) References JP-A-61-186068 (JP, A)

Claims (1)

[Claims] 1. A thermal transfer printing apparatus for individually controlling the time of each current flowing through a plurality of heating elements arranged in a line according to the density, and generating a signal corresponding to a preset supplementary heating time. Depending on the output control counter and the signal supplied from the control counter,
Means for holding a value indicating the minimum density during the supplemental heating time, and generating reference density data that sequentially changes within the one-line printing time from the minimum density to a value indicating the maximum density after the supplemental heating time has elapsed; The control is performed by comparing the reference density data including the reference density data during the heating time with the input data to be transferred, and showing the heating element to which the current is to be supplied among a plurality of rows of the heating elements for each unit of density. A means for generating data, the reference density data being supplied, and the reference data inputted with the correction data set so that the relationship between the previously stored recording density and the reference density data is set to a straight line or a predetermined curve. A correction data generating circuit for outputting according to the density data; a means for supplying the correction data and the control data respectively, and for supplying a current to the heating element indicated by the control data for a time corresponding to the value of the correction data; Fever When the heating element is energized by means of passing a current through the body, a first state in which all the heating elements indicated by the control data are energized, and an odd line of the heating elements indicated by the control data is recorded Is applied to the odd-numbered heating elements, and even-numbered heating elements are used to record even-numbered lines. And a means for switching between a second state in which the heating element of (1) is energized, and a heat transfer type printing apparatus.