JPS63290783A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To prevent the surface of a recording paper from being smeared with an ink in a section ranging from a printing-ending position to a stopping position of a carriage, by stopping a printing head after continuedly moving the head for the period from the start of suspension of printing in a printing line or the end of printing to the time when the head is cooled. CONSTITUTION:After printing of a printing line is finished, namely, after the final dot in the printing line is printed, a carriage 1 is continuedly moved at the same velocity as that during printing, until the period of time T sufficient for cooling heat generating elements 3a of a printing head 3 elapses. During this period, take-up of an ink ribbon 10 is continued. After the lapase of time T, the carriage 1 is gradually decelerated, and is stopped. Thereafter, the head 3 is returned to a pressing-releasing position. Then, the carriage 1 is moved in the direction opposite to an arrow, and is returned to a printing-starting position in the printing line. Therefore, the quantity of heat per unit area imparted to the ink ribbon from the head is reduced, and a recording paper is not smeared with ink.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a thermal transfer printer.

Prior Art and its Problems In a conventional thermal transfer printer, the movement of the print head carriage is immediately stopped after printing of a print line is completed. That is, when the carriage is moved by a pulse motor, after printing is completed, the carriage moves for a time required for slow-down speed control, and then stops. When the carriage is moved by a DC or AC motor, after printing is completed, the carriage moves a little due to the inertia of the motor and then stops. After the carriage stops, the pressure of the print head against the platen is released, and winding of the ink ribbon is stopped.

Figure 3 shows the moving speed U of the print head relative to the ink ribbon and the heat f per unit area applied to the ink ribbon from the print head from the end of printing to the stop of the carriage drive motor in a conventional thermal transfer printer.
It shows the change in f1Q.

Since the driving of the heating element of the print head is stopped at the printing end time t1, immediately after printing ends, the temperature of the heating element of the print head decreases relatively rapidly to a certain extent due to heat dissipation, and the temperature of the heating element of the print head decreases to a certain extent. The amount of heat q per unit area also decreases relatively rapidly. However, immediately after printing ends, heat is still accumulated in the print head.

After the temperature of the heating element of the print head decreases relatively rapidly as described above, the temperature of the heating element decreases very slowly over time. On the other hand, since the moving speed U of the print head relative to the ink ribbon decreases at a rate of change greater than the rate of decrease in the temperature of the heating element, the heat f per unit area applied from the print head to the ink ribbon
f1Q once decreases immediately after printing ends, and then gradually increases. Therefore, the ink on the ink ribbon is softened, and the ink is transferred to the recording paper by the pressure of the print head.

As a result, there is a problem in that ink stains occur on the surface of the recording paper between the printing end position and the carriage stop position. This ink stain appears as a mist from the print end position to the carriage stop position, and appears as vertical streaks at the carriage stop position. Such a phenomenon is
This is particularly noticeable when printing of a print line ends after solid black printing has been performed and the print head temperature has become extremely high.

An object of the present invention is to provide a thermal transfer printer that solves the above problems.

Means for Solving the Problems The thermal transfer printer according to the present invention is characterized in that the print head continues to move from the start of printing interruption or the end of printing of a print line until sufficient time has elapsed to cool the print head. The print head is then stopped.

Example In FIG. 1, a carriage (1) is provided so as to be movable along a platen (2) extending in the left-right direction.
It is moved in the left-right direction by a carriage drive motor (pulse motor) via a wire (not shown). The carriage (1) includes a plurality of heating elements (3a) arranged vertically.
The ink ribbon winding motor (5) for rotationally driving the print head (3) having a print head (3), a print head swinging device (path shown), an ink ribbon winding shaft (4), and the winding shaft (4) is provided. ing. The print head (3) is moved by a carriage ( 1) is swingably attached.

The same position switching of the print head (3) is effected by a print head rocker. The print head (3) is normally located in the depressing position. Ink ribbon take-up motor (
5) is attached to the underside of the carriage (1).

The ink ribbon cassette (8) is removably attached to the carriage (1). A first ribbon core (8) is rotatably attached to a cassette core (7) fixed to one side of the cassette (6), and a carriage (1
) is provided with a second ribbon core (9) which meshes with and rotates with the winding shaft (4).

One ink ribbon (10) with ink applied to one side of the base is attached to these ribbon cores (8) (9).
) is wrapped. The ink ribbon (10) has its middle portion wrapped around the print head (3).

When the printing process is started, the print head (3) is moved to the pressing position by the print head swinging device, whereby the ink ribbon (10) and the recording paper (11) are pressed against the heating element (
3a) and the platen (2) are pressed together.

Further, the carriage (1) is moved in the printing direction (rightward) by the carriage drive motor, and the ink ribbon (10) is wound around the second ribbon core (9) by the ink ribbon take-up motor (5). To go. and,
By selectively driving each heating element (3a) according to the print data output from the printer control device, the ink of the ink ribbon (10) is transferred to the recording paper (11), and the ink is transferred to the recording paper (11). Predetermined printing is performed.

When the printing of the print line is completed, that is, when the last dot of the print line is printed, a sufficient time T has elapsed from the time when the printing was completed to cool down the heating element (3a) of the print head (3). The carriage (1) continues to move at the same speed as that during printing until the printing is completed. Time T is 0.
It is set to a time of 1 second or more, for example 0.1 second. The moving speed of the carriage (1) in this case may be set higher than the speed during printing. Also, during this time, the ink ribbon (1
0) also continues to be wound.

After the time T has elapsed, the carriage (1) is gradually decelerated and stopped. After this, the print head (3) is returned to the pressure release position. Then, the carriage (1) is moved in the opposite printing direction (to the left) and returned to the printing start position of the printing line.

Figure 2 shows the ink ribbon (
It shows changes in the speed U of the print head (3) and the amount of heat q per unit area applied from the print head (3) to the ink ribbon (10) with respect to lO). The carriage (1) is continuously moved at the same speed as during printing until a time T sufficient to cool down the print head (3) has elapsed from the time t1 when printing of the print line ends, and after the time T has elapsed, the carriage (1) is gradually moved. The vehicle is decelerated to a point t2, and is stopped at time t2. Since the carriage (1) is being moved at the same relatively fast speed as during printing, the print head (3) The amount of heat per unit area q given to the ink ribbon (10) from
is smaller than before. Therefore, after printing is completed, ink transfer to the recording paper (11) due to the pressing force of the print head (3) does not occur, and ink staining on the recording paper (11) does not occur.

In the above embodiment, while the carriage (1) continues to move until the time T has elapsed from the end of printing of the print line, the ink ribbon (10) is continuously taken up. Immediately after printing is completed, the winding of the ink ribbon (lO) is stopped, and then, when the carriage (1) has moved a predetermined distance, the ink ribbon (10) is wound again and the ink ribbon (lO) corresponding to the final dot is wound. The portion 10) may be peeled off from the recording paper (11).

Further, the printing head (3) may be switched to the pressure release position while the carriage (1) is continuously being moved from the point in time when the printing of the print line ends.

In addition, if printing is interrupted in the middle of the above printing line, that is, if there is a relatively long continuous portion in the printing direction that is not printed at all, control after the printing of the printing line ends after the printing interruption starts. Control similar to that may be performed. However, in this case, the carriage (1) is continuously moved for a predetermined period of time after the start of printing interruption and then stopped, and then the carriage (1) is moved again in the printing direction.

Note that thermal transfer printers that do not have an ink ribbon take-up motor separate from the carriage drive motor, for example,
The present invention is also applied to a thermal transfer printer in which the ink ribbon (10) is wound up by transmitting the moving force of the carriage (1) to the take-up shaft (4) of the ink ribbon (10) via a pinion and a rack. can do.

Effects of the Invention In the thermal transfer printer of the present invention, the print head is continuously moved from the start of printing interruption or the end of printing of a print line until sufficient time has elapsed to cool the print head. Since the ink is stopped, the amount of heat applied from the print head to the ink ribbon per unit area decreases after printing of a print line starts or ends, and ink stains do not occur on the recording paper.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a partially cutaway plan view of a thermal transfer printer;
Figure 2 is a graph showing changes in the speed of the print head relative to the ink ribbon and the amount of heat per unit area applied from the print head to the ink ribbon after the printing of a print line is completed;
The figure is a graph showing changes in the speed of the print head relative to the ink ribbon and the amount of heat per unit area applied from the print head to the ink ribbon after printing a line in a conventional thermal transfer printer. (1) Carriage, (3) Print head, (
3a)... Heating element, (10)... Ink ribbon, (
11) Recording paper. that's all

Claims (1)

[Claims] A thermal transfer printer in which the print head is continuously moved from the start of a printing interruption or the end of printing of a print line until sufficient time has elapsed to cool the print head, and then the print head is stopped.