JPS59129171A - Thermal head - Google Patents

Abstract

PURPOSE:To improve the definition and print speed by providing the conductive layer for applying an electric current to both ends of plural respective heating resistance layer and at the same time by providing the row of conductive layers at positions different therefrom. CONSTITUTION:A glaze layer 2 is provided on the base 1 of ceramic or the like and an intermediate conductive layer 6 thereon. Then, an insulation layer 7 is provided on the part except the contact hole 8 thereon and a heating resistance layer 3, conductive layers 4a and 4b and a protective layer (abrasion resistance layer) 5 are provided thereon as abovementioned. Thus, by providing three pieces of electrodes in the heating resistance layer 3, the resolution is doubled when electrical current is selectively applied among them.

Description

[Detailed description of the invention] [Technical field to which the invention belongs] The present invention relates to facsimile and computer terminal equipment.

The present invention relates to a thermal head of a thermal recording device such as a printer device or a recorder.

[Prior art]

Conventionally, as shown in FIG. 1, a thermal head used for color-forming type or dye-transfer type thermal recording generally has a glaze layer 2 on a substrate 1 made of ceramic or the like in order to store heat generated by a heat-generating resistor layer 3. is provided. On the glaze layer 2, a plurality of heat generating resistor layers 3 made of thick or thin films of nichrome, tantalum nitride, etc. are arranged in parallel to each other in a slit shape to form a heat generating resistor layer sequence. Each heating resistor layer 3 has a pair of current-carrying layers 4a in contact with its upper surface.

4b face each other at a predetermined interval and are connected. The current-carrying layers 4a and 4b are usually made of a high-melting point metal such as tungsten, titanium, or molybdenum, which can sufficiently withstand the heat generated by the heat-generating resistance layer 30. The top layer is a heating resistance layer 322 multilayer 4a
, 4b is provided.

The thermal head is constructed by applying pulses of current to the current-carrying layers 4a, 4b in a predetermined pattern in pairs.
The heating resistor layer 3 within the opposing interval 4b generates heat, and a predetermined pattern is recorded on the thermal paper that is in sliding contact with the heating resistor layer 3.

In recent years, high definition and high speed thermal recording methods using this type of thermal head have been promoted. For example, high definition can be achieved by miniaturizing the heat generating resistor layer of the thermal head and increasing the linear density.Currently, it is possible to miniaturize the heat generating resistor layer to about 8 lines/mm, which is not practical. has been made into Regarding speeding up, thermal recording takes a relatively long recording time of 1 to several milliseconds, so from the convenience of use and manufacturing and the required speed, it is necessary to store the recorded information for each scan in memory.
A parallel recording method is used to store data in one row and simultaneously record in parallel to increase speed. However, in the heat-sensitive recording method using a thermal head, even if a parallel recording method is adopted, there is a limit to the ability to achieve high definition and high speed due to constraints on recording time. That is, if the focus is on high definition, it is possible to cope with the miniaturization of the heat generating resistive layer of the thermal head by increasing the linear density, but on the other hand, this increases the recording time and goes against high-speed recording. Furthermore, if the focus is on speeding up, high definition cannot be achieved. This means that the sharpness and sharpness correspond to its intended use.
It is decided which of the recording speeds is more important, and accordingly the number of units of the heat generating resistive layer of the thermal head, that is, the linear density is selected. In other words, by selectively determining the configuration of the thermal head, the sharpness can be improved.

This means that the recording speed is uniquely determined.

Therefore, there is a drawback that the sharpness and recording speed corresponding to each character image to be recorded cannot be set arbitrarily.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks and to provide a thermal head capable of high-definition, high-speed, and economical thermal recording in accordance with the required recording surface.

[Structure of the invention]

According to the present invention, the current-carrying layer is attached to the heat-generating resistor layer of a thermal head including a plurality of heat-generating resistor layers and a pair of current-carrying layers connected to both ends of the heat-generating resistor layers for energizing the heat-generating resistor layers. and a current-carrying layer array connected at a different position than the
You will get a Mulhead.

[Explanation of Examples]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a sectional view showing one embodiment of the present invention.

A glaze layer 2 for accumulating heat generated by a heat generating resistor layer 3 is provided on a substrate 1 made of ceramic or the like.

An intermediate conductive layer 6 is formed on a substrate 1 on which a glaze layer 2 is provided. Furthermore, an insulating layer 7 is formed on the intermediate current-carrying layer 6 to electrically insulate the intermediate current-carrying layer 6 and the heating resistor layer 3 . A heating resistance layer 3 is provided on this insulating layer. A plurality of heat generating resistor layers 3 are arranged in parallel to each other in a slit shape to form a heat generating resistor layer array. Further, the heating resistor layer 3 is electrically connected to the intermediate current-carrying layer 6 through a connecting hole 8 provided at an intermediate position in the insulating layer 7 below the heating resistor layer 3. A pair of current-carrying layers 4a and 4b are connected to both ends of the upper surface of the heating resistor layer 3, facing each other at a predetermined distance. A wear-resistant layer 5 is provided on the uppermost layer to protect three rows of heat generating resistive layers and two rows of current-carrying layers 4a and 4b.

FIG. 3 shows an electrical equalization circuit for the thermal head described above. To explain the relationship between FIG. 3 and FIG. 2, the heating resistor layer 3 in FIG.
, 4b rows are conductors 24a, 24b.

Intermediate current-carrying layer 6 corresponds to conductor 26 . In addition, the insulating layer 70
The connecting portion between the heating resistor layer 3 and the intermediate current-carrying layer 6 through the connecting hole 8 corresponds to the connecting point 28 in FIG. 3, and the resistor 23 is divided into two resistors 23a and 23b at the connecting point 28.

FIG. 4(a) is a plan view showing a part of the heating resistor of the thermal head of the present invention, and FIG. 4(b) and (C) show recording pixels that appear on the thermal recording paper by this heating resistor. It is. For example, when a heating current is passed through the heating resistor layer 3 from the current-carrying layers 4a and 4b, the Joule heat generated in the heating resistor layer 3 causes the heat-sensitive recording that is in contact with the heating resistor layer 3 to appear as shown in FIG. 4(b). The recorded pixels appear. Furthermore, when a heat-generating current is passed through the current-carrying layer 4a and the intermediate current-carrying layer 6, as shown in FIG.
The recording pixels shown in C) appear. That is, an intermediate current-carrying layer 6 is provided within the heating resistance layer 3, and between the current-carrying layers 4a and 4b,
Alternatively, the size of the recording pixels on the thermosensitive recording paper can be selected by selecting either the current-carrying layer 4a or the intermediate current-carrying layer 6 to flow a heating current.

In the above embodiment, one intermediate current-carrying layer is provided at the center of the heat-generating resistor layer, but it is also possible to provide one intermediate current-carrying layer at a plurality of locations within the heat-generating resistor layer. Therefore, in the conventional thermal head, the recording pixel size is uniquely set, and it is impossible to select the recording pixel size corresponding to the required sharpness, but with the thermal head of the present invention, This has the advantage that the size of the recording pixel can be arbitrarily selected depending on the sharpness required for the image.

The size of the recording pixel is selected by switching the intermediate current-carrying layer in the thermal head, and the amount of heating current or the heating current supply time to the heat-generating resistor layer is appropriately controlled in accordance with the size of the recording pixel.

For example, if the size of the recording pixel is large, the amount of heat generation current may be increased in proportion to the size of the recording pixel, or the heating energization time may be lengthened.In particular, if the amount of heat generation current is increased, the recording time may be shortened. effective.

[Detailed description of the invention]

As explained above, the present invention provides an intermediate current-carrying layer that connects the heating resistor layer of the thermal head at a point other than both ends thereof, thereby meeting the sharpness required for the image to be recorded.
This has the effect of obtaining optimal clarity and recording speed.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional thermal bed, Fig. 2 is a sectional view of an embodiment of the thermal head of the present invention, and Fig. 3 is a sectional view of a conventional thermal bed.
Electrical equalization circuit diagram of the thermal head shown in Figure 4 (a)
) is a plan view showing a part of the heat generating resistor of the thermal head of the present invention, and tb) and (c+ in the same figure are plan views showing recording pixels appearing on the thermal recording paper by the heat generating resistor in figure (a)). 1...Substrate, 2...Glaze layer, 3...
...Heating resistance layer, 4a, 4b... Current carrying layer, 5... Wear resistant layer, 6... Intermediate current carrying layer, 7... Insulating layer, 8... Connection hole, 23
...Resistor, 24a, 24b, 26...
...Conductor, 28...Connection point. / Figure 1 Z mouth almost 3 wa (ku λ graduate 4

Claims (1)

[Claims] In a thermal head including a plurality of heat generating resistive layers provided on a substrate, and a pair of conductive layers connected to both ends of the heat generating resistive layers for energizing the heat generating resistive layers, the heat generating resistive layer is connected to the conductive layer. A thermal head characterized in that it includes current-carrying layers connected at different positions.