JPS585279A - Thermal head - Google Patents

Abstract

PURPOSE:To obtain a thermal head having a high resolving power and capable of independently controlling recording dots, by using a system in which plural heads provided with large numbers of heating resistors are arranged in such a way that the heating resistors are alternately set and a common electrode is connected to the heating resistors. CONSTITUTION:On a base plate 20, segment electrodes 23 and 24 and a common electrode 25 are formed by screen printing method, etc., and then heating resistors 21 and 22 are formed in such a way as to bridge the segment electrodes 23 and 24 with the common electrode 25, forming two heads H1 and H2. The distance between the heads H1 and H2 corresponds with a subscanning distance (or the moving distance of recording paper), and the respective length corresponds with the width of the recording paper. Also, the heating resistor 22 of the head H2 is arranged alternately with the heating resistor 21 of the head H1. Thus, recording dots can be formed with a density two times as much as one head.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal head for reproducing and printing image information transmitted by, for example, a facsimile machine.

The thermal head is constructed by setting a large number of electrodes separated by small intervals, such as a thin heat generating resistor IFt, and selectively applies a voltage between the electrodes to generate a resistive band between the electrodes. It generates heat and uses the heat to place images on the recording paper. In other words, the resistance band is divided into a large number of electrodes, each of which serves as a recording dot that represents a recorded image. Set along the scanning direction.

That is, based on the transmission information read by the main scanning line that scans the transmission special image in its width direction, the electrode voltage is controlled along the longitudinal direction of the resistance band, and the read fI-
To scanning line tube thermal.

Reproduce it on the paper by hand. Then, in contrast to the main scan in the direction in which this resistance band extends, the recording paper is moved in the vertical direction to perform l1Ils& scanning, and the southern image is reproduced on the recording paper. Find something to do.

Recorded by the thermal head used in this way*
When reproducing an image on a high-quality 1 ll.
This is the first thing I can reproduce. However, increasing the dot density requires reducing the distance between the electrodes, which determines the heat generation range t% of the resistance band, which inevitably increases productivity, and there is a technical limit.

Therefore, at present, 3 to 6 arrangement dos and toes are formed in the range 1-, but in order to record and reproduce a sufficiently high-quality image g11, it is necessary to form an arrangement in the range l■. Therefore, it is desirable to form, for example, 12110 dots.

In view of these points, the patent application filed by the applicant in 1973
As shown in No. 5-184458, for example, by using a head capable of forming six recording dots within a range of 1 m, 12 recording dots are formed within a range of, for example, 1. The thermal head is designed to extend in the main scanning direction, and is capable of forming 6 recording dots in a range of 1. As shown in Figure 1, the recording dots by the second head H2 are formed between the dots recorded by the head H1 of the head 1, so that the recording dots are formed in a range l- on the recording paper.
It forms two dots and enables high-density, high-resolution images to be reproduced.

Specifically, as shown in Fig. 2, the heat generated for recording is extended in the main scanning direction, which is the width direction of the recording paper perpendicular to the moving direction (-scanning direction) of the recording paper indicated by the arrow. First and #I2 resistance bands that make up the body 11 * I J
Set the interval specified by 't' to set the parallel state. Each of the resistance bands 11 and 12 has a pair corresponding to a main scanning line, and the interval between them is set to correspond to the distance that the recording paper moves in one main scanning line period. Ru.

In each of the resistance bands 11 and 12, the longitudinal direction is divided into minute intervals, and segment electrodes I J *, each connected to an external lead wire, are connected to the external lead wire.
I J b-1J4a, J4b... are provided, and the space between each segment electrode is divided into two, so that common electrodes @15a115b... and 16
a, 16b... are provided. That is, the first and second
The resistance bands JJ and JJ are the segment electrodes 13, respectively.
m 113b... and common electrode 15 a e I
5b..., and segment electrodes 74a, Z4b.
... and the common electrodes 16m, 16b..., and by passing a current between the adjacent segment electrodes and the common electrode, heat is generated in the resistance band portion between the electrodes. Dots are placed on recording paper. And this first and second
jlIl and the second
Nohe, de HJ.

Hjt@form.

In the case of Jin, as explained in Figure 1, the 1st and 1I
The recording unit that generates heat and performs one recording, separated by each electrode of the head H1 and Hl of E2, is a recording unit with an interval between recording dots in the main scanning direction at PHJ and HJ, respectively, to the first and second strings. Set with a difference of 1/2.

Here, the common electrode 15*ellb... and 1gm, 16 in the first $P and second resistance band 11.1:1
b... are commonly connected between adjacent adjacent ones, and the commonly connected unit common electrodes are alternately connected to the first
and the common line rv, xs of series 2, and the heating resistor portion corresponding to each recording unit is connected to each head Hx, H; by the signal CI*Cj for this line and the signal between the counter segment electrode. Then, a heating current corresponding to the recording dots is supplied.

For example, the recording unit indicated by a in the figure is used to record data.

If you are trying to record a common line 17, common 11% I' a % segment electric
A current tlL is applied to the circuit, causing the resistor defined by the electrodes 16a and 14a to generate heat.

However, when the electric current S is supplied to cause a current to flow from the common electrode 16a to the segment electrode 74m as described above, in addition to the current path to the aS position 1, as shown by the broken line in the figure, +f and b A current path is also formed through the resistor portion corresponding to the arrangement unit shown in FIG.

In this case, the total resistance value forming the other current paths is sufficiently large compared to the resistance value in the recording unit a section to be recorded, and although no large current flows through the other current paths, the There is a good chance that it will cause dirt.

This invention was made in view of the above points, and it is possible to form recording dots with high density and sufficient density in the state shown in FIG. The aim is to provide a Boolean head P that allows the recording of L to be controlled sufficiently independently.

An embodiment of the present invention will be described below with reference to FIG. That is, as shown in Figures 3 and 4, a large number of heating resistors 21 m *; The first head H1 is formed by linearly disposing the head at intervals. In addition, a large number of heating resistors 22m and 12b are arranged along the main scanning line direction by setting a specified interval from the first head 1.
. . are arranged independently and linearly parallel to the first head H1 to form a second head H2f. Then, each heat generating resistor jJa, JJb... and 21m, 21 of this first and second spatula t'HJ and HJ
b...Segment electrode 231°J for each
Jb...and 24*, 14b...t-connection.

Further, as described above, each heating resistor 21 a + J of the ninth head 1 and the second head HJ#Hj is set in a parallel state.
I b ”・and j j * * j J b ・
A common electrode 25 extending in the main scanning line direction is formed between the first and second HJs so as to be commonly connected to the HJs.

In this case, the lengths of the first and second heads H1 and H2 are set to correspond to the recording paper width when reproducing images, and the distance between the first and second heads H1 and HJ is as follows: The regular scanning distance corresponding to the main scanning line period, specifically, 1
It is set in accordance with the moving distance of the placed paper while recording and forming the main scanning lines of the book. In addition, the heat generating resistors 22*, 22b... of the second head H2 are arranged alternately in the main scanning line direction with respect to the heat generating resistors 21m, 21b... of the first head H1. They are set at different positions as shown in FIG. 1, and recording is performed as explained in FIG.

In such a thermal head, as shown in cross section in FIG. 5, segment electrodes 23, 24 and common electrodes 25 are first formed of conductors on the surface of the substrate 20 by screen printing or the like, and each segment electrode 23. 24 and the common electrode 25, each of the heating resistors 21 and 22't may be formed by screen printing or the like.

Note that in the above embodiment, the first and second heads HxaH
However, the number of heads may be further increased. In this case, the position of the heat generating member of each head may be set to be sequentially different in the main scanning line direction.

As described above, according to the present invention, for example, 6
With the production technology to form 1 piece, 1
Recording dots are independently recorded in a range of 12 or more at a density of 12 or more! For example, it is possible to effectively transmit and reproduce image side information such as in a facsimile machine with extremely high resolution.

[Brief explanation of the drawing]

FIG. 1 shows the arrangement S according to the present invention.
The ninth diagram, Figure 2, is based on what has been considered so far.
Figure 3 shows a thermal head according to an embodiment of the present invention. A configuration diagram of P seen from the plane, 4th g is ■-VOW of the irises 3 diagram
This is a picture of the direction. 20-...Substrate, 21e; 11emllb"', 22h
J j a a J J b...'ilr thermal resistor,
23g23&ejob..., 14-j 4 ae
J 4 b...Segment electrode, 25...Common electrode, Hl...First head, Hl...Go to song 2,
Do. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] It is equipped with a plurality of heads configured by arranging a large number of heat generating resistors connected to dragon element electrodes at minute intervals so as to extend in one direction in the main scanning direction. The heating resistors of each of the plurality of head groups are set to be parallel to each other with an interval between them, and the heating resistors of each head group are set at different positions along the main scanning direction from the heating resistors of other head groups. and to each of the above, #p
The interval # is the scanning distance lIl in the sub-scanning direction during one scanning period! The thermal head is characterized in that it is configured so that the common electrode is connected to each heating resistor of each of the head groups.