JPH10324014A - Thermal transfer printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance transfer efficiency of a thermal print head. SOLUTION: A thermal print head 6 is pressed against a platen 12 from above a print medium 38 and a transfer current pulse is applied to the thermal print head 6 under that state. Consequently, the thermal print head 6 generates thermal energy for printing on the print medium 38. The thermal print head 6 is applied with the transfer current pulse more than once for each print data of one line and transfer is performed more than once at the print position for one line.

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 for performing thermal transfer printing on a print medium on a platen using thermal energy of a thermal print head.

[0002]

2. Description of the Related Art In a conventional thermal transfer printer, a paper feed mechanism driven by a stepping motor is provided with a motor driving current pulse (2) as shown in FIG.
Print medium, such as paper,
m (0.04 mm), and the print data for one line is transferred to the print medium by the thermal energy of one transfer current pulse (4) applied to the thermal print head.

[0003]

As described above, in the prior art in which the transfer current pulse (4) is applied to the thermal print head once for each line of print data, as shown in FIG. However, there was a problem that the temperature did not reach the temperature T2 at which a sufficient print density was obtained, and the print density was insufficient. Further, when transferring the print data of the next line, the thermal print head sets the transferable temperature T1.
It will be in a lower cooling state. There is a problem that wrinkles are generated on the print medium as a sheet material due to the temperature change of the head. An object of the present invention is to solve the above problems.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a thermal printing head which presses a printing medium against a platen from above a printing medium, sends the printing medium in a predetermined direction, and applies a thermal printing head to the thermal printing head. In a thermal transfer printer in which printing is performed on a print medium on the platen with thermal energy generated by a transfer current pulse, two or more transfer pulses are applied to the thermal print head for each line of print data, and The transfer is performed two or more times at the printing position of the minute.

[0005]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG.
(6) is a thermal print head of the thermal transfer printer (8), and has a built-in temperature sensor (10) composed of a thermistor. The thermal print head (6) can move up and down with respect to the roller-shaped platen (12) so that the printer (8) can move up and down.
(Not shown). Platen (1
Before and after 2), a paper feed mechanism including transport rollers (14) (16) and a pressure roller (18) is arranged. A roll paper supply reel (22) is rotatably supported by support rollers (24) and (26) of the body of the printer (8).

Reference numeral (28) denotes an ink ribbon supply reel. The ink ribbon (30) fed out from the reel passes through a guide roller (32) and passes through a thermal print head (6).
And a platen (12), and is wound around a take-up reel (36) via a guide roller (34).

A print medium (38) such as a sheet drawn from a roll paper supply reel (22) is supplied to a guide roller (4).
0), is inserted between the transport roller (14) of the paper feed mechanism and the pressure roller (18), and is inserted between the platen (12) and the thermal print head (6) via the guide (42). Have been. Further, the print medium (38) passes through a guide (42), and is conveyed by a transport roller (16) of a paper feed mechanism.
Between the pressure roller (20) and the guide (4).
4) Guided above.

The thermal print head (6) is connected to a head elevating motor (46) comprising a stepping motor, and is driven up and down by the motor (46). When the thermal print head (6) is lowered, the ink ribbon (30) and the printing medium ( 38) so as to press against the platen (12) from above. The data input section of the thermal print head (6)
The head data control circuit (48) is connected to the head data control circuit (48).
8), a transfer current pulse (50) for printing is supplied.

The platen (12) and the transport roller (1)
4) (16) is connected to the feed motor (52).
The feed motor (52) is composed of a stepping motor. When one motor drive current pulse (54) is input, the print medium (38) is moved a predetermined distance A (0.04 m).
m), and is configured to be conveyed to the left in FIG.

[0010] Further, the take-up reel (36) is shown in FIG.
Ribbon take-up motor (54) driven counterclockwise in the middle
Also comprises a stepping motor. Each of the motors (46) (52) (54) is connected to a motor control circuit (58) controlled by a CPU (56). The CPU (56) has an interface (5
8), a data input device (60) is connected, and character information, graphic information and other print information can be input to the CPU (56) from the keyboard of the data input device (60). Have been.

The head data control circuit (48)
Transfer current pulse with print data for the line (50)
As shown in FIG. 1, when one motor drive current pulse (54) is supplied to the feed motor (52), the current is supplied twice, and once when the next pulse (54) is supplied, It is configured to supply three times in total.

Next, the operation of the present embodiment will be described. When the printing operation starts, the transport rollers (14)
(16) and the platen (12) rotate, and the print medium (38) is fed between the thermal print head (6) and the platen (12) in the direction of the arrow (B). On the other hand, when one drive current pulse (54) is applied to the feed motor (52), two transfer current pulses (50) are applied to the thermal print head (6), and the next drive current pulse (54) is applied. When applied to the feed motor (52), one transfer current pulse (50) is applied to the thermal print head (6) and the print medium (38) is moved to about 0.08 on the platen (12).
During the movement, the head data control circuit (48) transfers a transfer current pulse (5
0) is supplied three times.

This operation is repeated, and the print medium (3
8) Printing is performed. During printing, the ribbon (30)
The print medium (38) is wound around the take-up reel (36) at the same speed as the transport speed. As shown in FIG. 2, the temperature (62) of the thermal print head (6) exceeds the transferable temperature T1 (the melting temperature of the ink of the ink ribbon) by the first application of the transfer current pulse (50), and While waiting for the transfer current pulse (50), the temperature is cooled to the transferable temperature T1, and the temperature is increased from the temperature T1 to the temperature T2 at which a sufficient printing temperature can be obtained by the application of the next transfer pulse (50).

By applying the transfer current pulse (50) three times at the printing position of one line, the printing thermal energy of the thermal printing head (6) increases as shown in FIG. The print media (3
In 8), printing is clearly performed. As described above, if the transfer is repeated three times for each one-line print data, the temperature of the thermal print head (6) rises, and the printhead does not have to.
Therefore, during printing, the temperature of the head (6) is constantly monitored by the temperature sensor (10), and when the head temperature becomes 65 ° C. or higher, printing is stopped under the control of the CPU (56).
When the temperature of the head (6) reaches 60C, printing is started again.

In the above embodiment, the transfer is performed three times for one-line print data. However, the transfer may be performed twice, or may be performed four times or more. In the case of two transfers, as shown in FIG. 3, the thermal energy of the thermal print head is twice as much as that of the conventional one transfer, so that the image quality is improved and the transfer efficiency is improved.

[0016]

As described above, according to the present invention, since the transfer is performed twice or more at the printing position for one line, a sufficient printing temperature can be obtained, and wrinkles of the printing medium can be prevented. can do.

[Brief description of the drawings]

FIG. 1 is a time chart showing a relationship between a motor drive pulse and a transfer pulse.

FIG. 2 is a time chart showing a relationship between a transfer pulse and a surface temperature of a thermal print head.

FIG. 3 is a time chart of thermal energy in two transfers.

FIG. 4 is a schematic structural view of a thermal transfer printer.

FIG. 5 is a schematic block diagram of the thermal transfer printer.

FIG. 6 is a time chart showing the relationship between a conventional motor drive pulse and a transfer pulse.

FIG. 7 is a time chart showing a relationship between a conventional transfer pulse and a surface temperature of a thermal print head.

[Explanation of symbols]

 2 Motor drive current pulse 4 Transfer current pulse 6 Thermal print head 8 Thermal transfer printer 10 Temperature sensor 12 Platen 14 Transport roller 16 Transport roller 18 Press roller 20 Press roller 22 Roll paper supply reel 24 Support roller 26 Support roller 28 Ink ribbon supply Reel 30 Ink ribbon 32 Guide roller 34 Guide roller 36 Take-up reel 38 Print medium 40 Guide roller 42 Guide 44 Guide 46 Head elevating motor 48 Head data control circuit 50 Transfer current pulse 52 Feed motor 54 Ribbon take-up motor 56 CPU 58 Interface 60 data input machine

Claims (1)

[Claims] 1. A thermal print head is pressed against a platen from above a print medium, the print medium is sent in a predetermined direction, and thermal energy by a transfer current pulse applied to the thermal print head is applied to a print medium on the platen. In a thermal transfer printer adapted to perform printing, two or more transfer pulses are applied to the thermal print head for every one line of print data, and two or more transfers are performed at a print position for one line. A thermal transfer printer, comprising: