JPH04307263A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To provide a small-sized inexpensive thermal transfer printer simultaneously printing many lines by increasing the number of heaters by miniaturizing a thermal printing head, an FTC and a head driver circuit and reducing the number of them. CONSTITUTION:A thermal transfer printer has a thermal printing head wherein common electrodes 5 of at least two or more systems are gathered and the individual electrodes of the adjacent heaters 3 connected to the common electrodes 5 of different systems are short-circuited and the means loaded with said head and changing over the supply of a current to the common electrodes 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal print head and a thermal transfer printer, and more particularly to a serial type thermal print head and a thermal transfer printer that print multiple lines simultaneously by increasing the number of heating elements.

0002

2. Description of the Related Art FIG. 6 is a schematic diagram showing a conventional thermal transfer printer. The thermal print head is connected to a control circuit via an FPC 6. FIG. 5 is a plan view showing the structure of a conventional thermal print head. The thermal print head is made by forming a glass glaze on a ceramic substrate 1, connecting a heating element 3, individual electrodes 4 and a common electrode 5 on the left and right sides of the heating element 3, and forming a protective film on the outermost layer.

The same number of head drivers 7 as the heating elements 3 of the thermal print head are connected to the control circuit, and the head drivers 7 are controlled according to print data to cause current to flow through each heating element 3.

However, with this structure, in a printer that uses a large number of heating elements to print multiple lines at the same time, the number of head drivers increases in accordance with the number of heating elements. Furthermore, since the number of individual electrodes increases, the horizontal dimension of the head and FPC
The width of the image becomes larger.

[0005]

[Problem to be solved by the invention] In this way, in the conventional example,
As the number of heating elements increases, the number of individual electrodes increases accordingly, and the width of the head and FPC increases. Additionally, the number of head drivers increases, which is a major factor in increasing costs and increasing the size of printers.

An object of the present invention is to provide a small-sized, low-cost printer that can simultaneously print multiple lines by increasing the number of heating elements.

[0007]

[Means for Solving the Problems] The present invention includes a thermal print head in which at least two systems of common electrodes are aggregated and individual electrodes of adjacent heating elements connected to the common electrodes of different systems are short-circuited; The present invention is a thermal transfer printer characterized by having means for switching power supply to a common electrode group.

[0008]

[Embodiment] Fig. 1 shows a first embodiment of the thermal print head of the present invention, in which the common electrode 5 is assembled on the right side of the heating element row 3 (the part near the end surface of the ceramic substrate) to form two systems. It is characterized by The common electrode 5a is connected to the odd numbered heating element row 3, and the common electrode 5b is connected to the even numbered heating element row 3. Where the common electrodes intersect,
They are insulated from each other because they have a multilayer structure with an insulating film in between.

Furthermore, individual electrodes of adjacent heating elements are short-circuited to reduce the number. As a result, the width of the head and FPC becomes about half that of the conventional example.

FIG. 2 is a schematic diagram showing an embodiment of a thermal transfer printer equipped with a thermal print head of the present invention. The difference from the conventional method is that the number of head drivers 7 is halved and that power is supplied to the common electrode 5 through two systems.

A CP that controls the entire printer based on print data sent via the interface 8
When U9 outputs a HIGHT or LOW level signal, the inverter 10 and transistors 11,1
The power supply from the head power supply 14 is connected to the common electrode 5 through 2.
Select whether to use the electrode a or the common electrode 5b.

[0012] With this, even if the head driver is common to two heating elements, printing is possible by switching the power supply to the common electrode.

FIG. 3 shows a second embodiment of the thermal print head of the present invention, which differs from the first embodiment in that the common electrode 5 is folded back and passed between adjacent heating elements 3 to connect to the individual electrodes 4. The point is that they are led out in the same direction and assembled in two systems just before the pressure contact part with the FPC.

With such a structure, the width of the head and FPC can be reduced as in the first embodiment. Furthermore, since the common electrodes are assembled into two systems, not at the end face of the ceramic substrate but just before the pressure contact portion with the FPC, the position of the heating element can be brought closer to the end face of the ceramic substrate. As a result, the ink ribbon can be peeled off when heated, and beautiful prints with few voids can be obtained even on paper with low smoothness.

Furthermore, since the common electrode is directly connected to each heating element, printing with less uneven printing density is possible without being affected by a voltage drop due to the resistance of the common electrode.

FIG. 4 shows a third embodiment of the thermal print head of the present invention, which differs from the first and second embodiments in that the heat generating element 3 is divided into two heat generating elements 3a and 3b, and a common The point is that the electrodes 5 are led out in the same direction as the individual electrodes 4 and are assembled in two systems just before the pressure contact part with the FPC.

With such a structure, the width of the head and FPC can be reduced as in the first and second embodiments. Furthermore, since the common electrode does not pass between adjacent heating elements, the pitch interval between the heating elements can be narrowed, making it possible to increase the density.

[0018]

[Effects of the Invention] As explained above, a thermal transfer printer is equipped with a thermal print head in which at least two systems of common electrodes are aggregated and the individual electrodes of adjacent heating elements connected to the common electrodes of different systems are short-circuited. By providing a means to switch the power supply to the common electrode group, it is possible to downsize and reduce the number of thermal print heads and head drivers, making it possible to increase the number of heating elements and make printers that can print multiple lines simultaneously smaller and cheaper. Can be provided at cost.

In this embodiment, there are two systems of common electrode groups, but even greater effects can be expected if the common electrode groups are made into more systems.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a thermal print head of the present invention.

FIG. 2 is a schematic diagram illustrating a thermal transfer printer of the present invention.

FIG. 3 is a plan view showing a thermal print head according to a second embodiment of the present invention.

FIG. 4 is a plan view showing a thermal print head according to a third embodiment of the present invention.

FIG. 5 is a plan view showing a conventional thermal print head.

FIG. 6 is a schematic diagram illustrating a conventional thermal transfer printer.

[Explanation of symbols]

1. ceramic substrate 2. glass glaze 3. heating element 4. individual electrodes 5. common electrode 6. FPC 7. head driver 8. interface 9. CPU 10. inverter 11,12. transistor 13. I/O 14. head power

Claims (2)

[Claims] Claim 1: A serial type thermal print head in which a plurality of heating elements are arranged in a row, at least two systems of common electrodes are grouped together, and individual electrodes of adjacent heating elements are connected to the common electrodes of different systems. A thermal transfer printer characterized by a short circuit. 2. The thermal transfer printer according to claim 1, further comprising means for switching power supply to the common electrode group of the thermal print head.