JPH01150558A - Thermal printer - Google Patents

Abstract

PURPOSE:To enable the setting of the temperature of heat to be released at a low level by pre-heating at least an ink film or a recording paper by utilizing a pre-heating mechanism. CONSTITUTION:An ink film pre-heating mechanism 10 comprising upper and lower pre-heating plates 10a, 10b is provided between an ink film roll 4 and a thermal head 6 in a printer main body 1 in such a manner as to hold an ink film 4a between the pre-heating plates thereof. In addition, a recording paper pre-heating mechanism 11 comprising upper and lower pre-heating plates 11a, 11b are also provided in the printer main body 1 in such a manner as to hold a recording paper 5A extracted from a recording paper roll 5 between the pre-heating plates thereof. Even when the temperature of heat released from the thermal head 6 is low, the thermal transferring of the ink film 4A onto the recording paper 5A is accomplished by pre-heating the ink film 4A and the recording paper 5A to a temperature above the room temperature before the start of printing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal printer that prints by thermally transferring ink from an ink film (ink ribbon) onto printing paper using a thermal head.

[Prior Art] As shown in Fig. 2, the above-mentioned thermal printer is as follows.
Inside the printer main body l, from the front (left side in the figure), there are an ink film take-up roll 2, a platen 3, an ink film roll (ink film supply section) 4 on which ink film is wound, and a printing paper is wound on the back of the printer main body l. Printing paper rolls (printing paper supply units) 5 are arranged parallel to each other and rotatable around their axes, and furthermore, a thermal head 6 for performing heat-generating printing is attached to the platen 3 at the lower front side of the platen 3. On the other hand, there is a structure in which they are arranged opposite to each other.

According to such a thermal printer, when the ink film 4A and the printing paper 5A pulled out from the ink film roll 4 and the printing paper roll 5 pass between the platen 3 and the thermal head 6, they are overlapped together and The ink coated on the ink film 4A is heated and melted by the thermal head 6, which generates heat at this time, to print on the printing paper 5A. After that, the ink film 4A and the printing paper 5A are separated, the printed printing paper 5A is discharged outside the printer body 1, and the ink film 4A is wound onto the ink film winding roll 2.

[Problems to be Solved by the Invention] Incidentally, the ink applied to the ink film 4A usually contains wax, and the melting temperature of this wax is usually 70 to 80°C. In order to melt , thermal energy shown by the following equation (1) is required.

Q R” (T M T R)・C+A ・・・・・・
・ (1) TM: Melting temperature of wax Tn: Room temperature C: Specific heat of ink A: Heat of melting of wax QR: Amount of heat required to melt ink from room temperature (cal/g) Therefore, in the thermal printer as described above, Since the ink applied to the ink film 4A is melted from room temperature, a large amount of thermal energy is required, and there is a problem in that the load on the thermal head 6 is large.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems.
In a thermal printer, the ink film is passed between a thermal head and a platen, and at this time, the ink film and the printing paper are brought into close contact with each other, and the ink from the ink film is thermally transferred to the printing paper by the heat of the thermal head. between the head, and
The present invention is characterized in that a preheating mechanism for preheating the ink film or the printing paper is disposed at least on one side between the printing paper supply section and the thermal plate.

[Function] Before printing on the printing paper, the preheating mechanism preheats the ink film and the printing paper (one of them), so that even if the heat generation M (heat generation temperature) of the thermal head is low, the ink on the ink film is Therefore, the heat generation temperature of the thermal head can be set lower than before.

[Example] An embodiment of the present invention will be described below with reference to FIG.

In the figure, the same components as those in FIG. 2 are given the same reference numerals to simplify the explanation.

In the figure, ■ is a printer main body, 2 is an ink film winding roll, 3 is a platen, 4 is an ink film roll wound with an ink film 4A, 5 is a printing paper roll wrapped with printing paper 5A, and 6 is a thermal head. The thermal head 6 has a plurality of heat generating resistors (paths shown) arranged in a line on the printing surface facing the platen 3, and these heat generating resistors are activated by the transmission of a pulse signal. The ink on the ink film 4Δ is then thermally transferred onto the printing paper 5Δ. Furthermore, a heat radiation fin 6a is attached to the back surface of the thermal head 6 for radiating heat accumulated by the heat-generating printing.

Inside the printer main body 1, between the ink film roll 4 and the thermal head 6, there are upper and lower preheating plates 10a sandwiching the ink film 4A pulled out from the ink film roll 4.

An ink film preheating mechanism 10 consisting of 10b is also provided. Similarly, inside the printer main body 1, there are paper sheets 5A pulled out from the printing paper roll 5, sandwiched therein.
A printing paper preheating mechanism 11 consisting of upper and lower preheating plates 11a and llb is provided.

Upper and lower preheating plates IQa of the ink film preheating mechanism 10
, 10b, and the upper and lower preheating plates 11a and llb of the printing paper preheating mechanism 11 are plate-shaped electric heaters having approximately the same width as the ink film 4A and the printing paper 5A, respectively. On the other hand, they are arranged in parallel with a predetermined gap.

Of the preheating plates 10a and 10b of the ink film preheating mechanism 10, the lower preheating plate 10b extends slightly forward (to the left in the figure) than the upper one, reaching near the thermal head 6. In addition, the upper and lower preheating plates 11a and 11b of the printing paper preheating mechanism 11 are used for printing paper 5A to be pulled out, respectively.
The front part is bent downward to follow the conveyance line. These preheating plates 10a, 10b, lla, and llb are made to generate heat by a power source (not shown), and preheat the ink film 4A and printing paper 5A to a predetermined temperature higher than room temperature, respectively. In particular, the temperature of the ink film preheating mechanism 10 is set to a level that does not dissolve the ink in the ink film 4A.

According to the thermal printer, the ink film 4A is drawn out from the ink film roll 4.

and printing paper 5A pulled out from printing paper roll 5
are preheated to a predetermined temperature by an ink film preheating mechanism 10 and a printing paper preheating mechanism 11, respectively, before reaching between the platen 3 and the thermal gutter 6. Then, in the preheated state, the ink of the ink film 4A is thermally transferred to the printing paper 5A by the thermal head 6,
printed.

Here, the amount of heat necessary for the thermal head 6 to melt the wax contained in the ink of the ink film 4A is the thermal energy shown by the following equation (2).

Q p= ('r, -Tp)・C+A...
・ (2) T, 4 = Wax melting temperature TP; Preheating temperature C: Ink specific heat Δ: Wax melting heat QP: Amount of heat required to melt the ink from the preheating temperature (cat/g) Equation (2) above QR- shown in the prior art section above
(T, -TR)・C+Δ...Comparing with the formula (1), it holds that T p> T [l, Q P < Q n,
For this reason, the ink film 4 which is preheated in advance
When ink A is thermally transferred to printing paper 5A which is also preheated, the ink can be melted with a small amount of heat.

Therefore, the ink film 4A and the printing paper 5A are preheated to a temperature higher than room temperature by the ink film preheating mechanism 10 and the printing paper preheating mechanism 11 before printing (thereby, the heat generation amount (heat generation temperature) of the thermal head 6 is lowered). However, the ink on the ink film 4A can be thermally transferred to the printing paper 5A.In other words, the heat generation temperature of the thermal nozzle 6 can be set lower than before, so the time for energizing the thermal head 6 can be shortened. The printing speed can be increased by

Further, there is an advantage that the load on the thermal head 6 due to the transmission of the pulse signal is reduced, and the life of the thermal head 6 is increased.

In this embodiment, both the ink film preheating mechanism 10 that preheats the ink film 4A and the printing paper preheating mechanism 11 that preheats the printing paper 5A are provided, but only one of them is provided, and the ink film 4A or printing Paper 5
Even if either one of A is configured to be preheated, the same effects as in the above embodiment can be obtained.

[Effects of the Invention] As explained above, according to the thermal printer of the present invention, the ink film and the printing paper, which are respectively compressed from the ink film supply section and the printing paper supply section, are passed between the thermal head and the platen, At this time, in a thermal printer that prints by thermally transferring the ink from the ink film to the printing paper by bringing the ink film and the printing paper into close contact with each other using the heat of the thermal head, the space between the ink film supply section and the thermal head and the printing paper supply A preheating mechanism for preheating the ink film or printing paper is disposed at least between the unit and the thermal head, and the preheating mechanism preheats the ink film or printing paper before printing on the printing paper. By preheating the paper, the heat generation amount (heat generation temperature) of the thermal head is low (although the ink in the ink film is dissolved, so the heat generation temperature of the thermal head can be set lower than before.

As a result, the power supply time to the thermal head is shortened, thereby increasing the printing speed, and the load on the thermal head due to the transmission of pulse signals is reduced, thereby increasing the life of the thermal head.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an embodiment of the present invention, and FIG. 2 is a schematic side view showing an example of a conventional thermal printer. 4... Ink film roll (ink film supply section), 4, A... Ink film, 5...
Printing paper roll (printing paper supply unit), 5A...
Printing paper, 6... Thermal head, 10... Ink film preheating mechanism, 11...
...Printing paper preheating mechanism.

Claims (1)

[Claims] The ink film and printing paper drawn out from the ink film supply section and the printing paper supply section, respectively, are passed between the thermal head and the platen, and at this time, the ink film and printing paper are brought into close contact with each other to absorb the heat of the thermal head. In a thermal printer that prints by thermally transferring ink from an ink film onto printing paper, the ink film or A thermal printer characterized by being equipped with a preheating mechanism that preheats printing paper.