JPS6235861A - Thermal head - Google Patents

Abstract

PURPOSE:To print images with an outline in horizontal direction emphasized without using special circuits, by constituting the first resistors of heating resistors and sequentially arranging the heating resistors in parallel to each other. CONSTITUTION:During printing, a controlling signal according to information signal is obtained in a controlling circuit 7, and is supplied to a driving circuit 3c constituted of driving IC chips 3b. Driving current from the driving circuit 3c is supplied selectively to the heating resistors 81, 9a, 9b, 82, 83 through individual electrodes 2c, thereby generating heat, and a thermal recording paper is brought into contact with a predetermined position corresponding to the heating resistor part while feeding the paper in a direction orthogonal to the direction of arrangement of the heating resistors 81, 9a, 9b, 82, 83, where by a desired image is printed on the paper.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to heat-sensitive recording paper, etc., for example. The present invention relates to a thermal head suitable for use in a printer that performs J-printing.

(Summary of the Invention) The present invention relates to a thermal head used in a printer that prints, for example, gradations on thermal recording paper, etc., in which an equivalent circuit has a plurality of first resistors connected in series; The 2i-th (i is 0.1.2...) connection points are connected to the respective individual drive electrodes, and the 2i-th connection points of this first resistor are
At least this first connection point is connected to the common electrode through the second resistor, respectively.
By configuring the resistor with heating resistors and arranging these heating resistors in parallel in sequence on an insulating substrate, it is possible to obtain a print with a clear internal quality that emphasizes the horizontal outline without using a special circuit. It has been made possible to do so.

[Conventional technology]

2. Description of the Related Art Conventionally, thermal heads shown in FIGS. 5, 6, and 7 have been proposed for use in printers that perform gradation printing on thermosensitive paper and the like. In FIGS. 5 and 6, (1) shows a heat sink made of aluminum, and a head substrate (2) is placed on this heat sink (1).
), drive board (3), etc. are provided.

This head substrate (2) is an insulating substrate (2) such as a glass glazed alumina substrate or a glass substrate, which has relatively good conductivity.
a) For example, Ta-5i formed in a plurality of substantially rectangular shapes on the
02 heating resistors (2b) are arranged independently in parallel at predetermined intervals, an individual electrode (2c) is connected to one end of each of the second heating resistors (2b), and each heating resistor (2c) is connected to the other end. A common electrode (2d) that is common to the resistor (2b) is connected, and a diode such as 5i02 (oxidized 1vi (2e) and It is constructed by laminating wear-resistant H (20) such as Ta205.The lower surface of the insulating substrate (2a) of this head substrate (2) is fixed to a predetermined position on this heat sink +11 with adhesive. For example, Mi(3+) is provided with a predetermined conductive pattern on an alumina substrate (3a) and a drive IC chip (3b), and this alumina substrate (3a) is fixed to a heat sink (1). Drive current is selectively supplied from the drive IC chip (3b) of the drive board (3) to the heating resistor (2b) via the conductor (4) and the individual electrodes (2c) of the head substrate (21), and this drive Selected heating resistor supplied with current (
2b) and at the same time abuts the thermal recording paper at a predetermined position corresponding to the heating resistor (2b) portion of this head substrate (2). By transferring the desired I onto this thermal recording paper.
Itll images etc. are printed. In this case, the thermal recording paper is such that its density changes depending on the temperature of the heating resistor (2b). In Figures 5 and 6, (5) covers the signal line to which the signal to be printed is supplied, and (6) covers the drive IC chip (3b), conductor (4), etc.
This is a protective molding material provided as shown in the figure. The circuit configuration of the conventional thermal head, as shown in FIGS. 5 and 6, is as shown in FIG.
T! 3 (7), and the control signal from the control circuit (7) is transmitted to the drive circuit (3c) of the drive IC chip (3b).
), and the drive circuit (3c) causes a drive current to flow through the selected individual electrode (2c), ie, the selected heating resistor (2b), to generate heat.

[Problem that the invention seeks to solve]

When printing with such a conventional thermal head, heat escapes from each heating resistor (2b), (2b), etc., so if the density of the image changes drastically, the printed image will be a blurry image. There was a drawback that it became In order to correct and improve such blurred images, it is possible to perform signal processing on the information signal to be printed, but in this case, a special enhancement circuit is required, especially when emphasizing contours in the line (horizontal) direction. Does it require digital signal processing and a circuit configuration? 3 [There was an inconvenience that it was sloppy.

In view of this, the present invention provides a special l1ilV! It is an object of the present invention to make it possible to obtain prints with clear image quality that emphasize outlines in the line (horizontal) direction without using F.

[Means for solving problems]

As shown in FIGS. 1 and 2, the thermal head of the present invention has a plurality of equivalent circuits, for example, n first resistors (81),
(82) ... (8n) are connected in series, and this first
Resistors (81), (82) ... (8n)
2i-th (i is 0.l, 2... The connection points are respectively connected to the individual drive electrodes (2C) and this first resistor (8
1), (82)...21st+1st connection point of (8n), that is, the connection point of resistors (81) and (82),
Connection point of resistors (83) and (84), resistor (85)
and (86) are connected to the second resistor (9a), respectively.
In the thermal head connected to the common electrode (2d) via (9b), at least this first resistor (8
z>.

(82)... (8n) is composed of a heating resistor (8*), (82)... (8
n) are sequentially arranged in parallel.

[Effect]

According to the present invention, the power distribution of the heating resistor in the arrangement direction of the information signal heating resistor, that is, in the horizontal on-off boundary, is made stronger t1M, which makes this heating resistor stronger than the other parts. Since it generates a large amount of heat, this boundary area is emphasized, making it possible to obtain a print with sharp image quality that emphasizes the outline.

〔Example〕

Hereinafter, one embodiment of the thermal head of the present invention will be described with reference to FIGS. 1 and 2. In FIGS. 1 and 2, portions corresponding to °ζ, FIGS. 5, 6, and 7 are designated by the same reference numerals, and detailed explanation thereof will be omitted. In this example, as shown in Figures 5 and 6, aluminum A is used.
A head base (21, number of drive bases (3), etc.) is provided on the heat dissipation & (1) consisting of I.
2a) For example, Ta-S formed in a plurality of substantially rectangular shapes on the
Heat generating resistor (81), (9a) made of iO2
, (9b), (82).

(83), (9a), (9b), (84), (
85).

(9a), (9b), . . . are provided independently and in parallel in a row in the horizontal direction at a predetermined interval. In this case, the heating resistors (81), (82), (83
)...(8n) are connected in series, and this heating resistor (
One end of the heating resistor (81), the connection point (102) of the heating resistors (82) and (83), the connection point (104) of the heating resistors (84) and (85), the heating resistor (8t), (
82).

(83) 2nd i (i is 0, 1.2...) H of...
The connection points (10o), (102), (1
04) Individual electrodes (2c), (2c) that are individually driven by respective drive circuits (3c)
・The heating resistors (81) and (82) are connected to
connection point (101), heating resistor (83) and (84)
connection point (1 (h), emitted!: C resistor (85) and (8
6) connection point (105)...i.e. heating resistor (81)
, (82), (8])...No2i+HJ\th connection point (1(h), (103).

(10s) . . . respectively as heating resistors (9a) and (
They are connected to the common electrode (2d) through the parallel circuit 9b). In this example, a constant voltage power source of E (V) is connected to the common electrode (2d), and the drive circuit (3c) is equivalently connected to a connection switch (lh) whose one end is grounded, (112), (l
li) ... is composed of °ζ. This fever H
l: Antibody (81).

(9a), (9b), (82),
(83), (9a).

(9b), (84), (86) ... Oxidation-resistant j → (2e) such as 5i02 and wear-resistant layer (2r) such as Ta205 are laminated on the individual electrodes (2C) and common electrode (2d). do.

The rest of the structure is the same as in FIGS. 5 and 6.

Since this example is configured as described above, during printing, the control circuit (7) obtains a control signal corresponding to the information signal, and this control signal is sent to the drive circuit (3c) composed of the drive IC chip (3b). The drive current from the drive circuit (3C) selectively passes through the individual electrodes (2c) to the heating resistors (81), (9a), (9b).

(82), (8i)..., generates heat, and transfers the thermal recording paper to the heating resistors (81), (8i)...
9a).

(9b), (82), (8i)... This heat generating resistor (81) is brought into contact with a predetermined position corresponding to the section.

(9a), (9b), (82), (8
3) A desired print is made on this thermal recording paper by transporting it in a direction perpendicular to the arrangement direction of.... In this case, the equivalent circuit in FIG. 1 becomes as shown in FIG. 2A, with heating resistors (81), (9a), (9
b) , (82-.

Let the resistance value of each of (8)... be RΩ.

Now, the connection switch (111) for the drive circuit (3C).

(112) are both on and other connection switches (l
13), (114)... are off.゛Each heating resistor (81) at this time,
(9a), (9b).

Examine the current flowing through (82), (83)...

If you look inside the block (121) in Figure 2, you can see the connection switch (
11) and (112) are both on, so the connection point (1
0o ) and (102) both have a potential of ov, so the current flows symmetrically from the common electrode (2d) of E (V). These heating resistors (81), (9a),
(9b).

Each current value of (82) is 11. fat + Ib
Let t l be 12.

Further, the current value If flowing through the heating resistor (83) is as follows.

Here, the resistance value of this denominator is equal to the combined resistance value Rc on the right side of the connection point (102). The right side of this connection point (102) can be represented as 〉1〉 in FIG. 2B. Since this circuit is considered to be repeated infinitely on the right side, it can be considered that (combined resistance value on the right side of the connection point (102)) - (combined resistance value on the right side of the connection point (104)) = Rc.

Therefore, RR+Rc , , Rc=ffR It is. Therefore It is.

In addition, to find the current values 1a2 and Ib2 flowing through the heating resistors (9a) and (9b), respectively, connected between the connection point (103) and the common electrode (2d), the connection point (10
The potential E3 of i) is.

Therefore It is.

Also, the current value 14. which flows through the heating resistors (84) and (85). To find IS, ■.

Also, the heating resistors (9a) and (9b) on the right side of this
) current value Ia3. Ib3. ■a4. Ib4...
・ is approximately zero, and the heating resistor (8g
).

(8v), (8s) Current value 1s flowing through...
+Iv, Is... are approximately zero. If you put this in a table, it will be as shown in the table below.

That is, when a signal such as that shown by the solid line in FIG. 3 is supplied to the thermal head of this example as an information signal to be printed,
These heating resistors (81) and (9a).

(9b), (82), (83), (9a
), (9b) . . . as shown by the broken line in FIG. 3, the power consumption changes in an accentuated manner at the point where the signal is switched from on to off. Therefore, the outline of the printed image is emphasized, making it possible to obtain a print with a clear fleshy texture.

Further, FIG. 4 shows another embodiment of the present invention. In the example of FIG. 1, the first resistor - (81), (82) (83)
... and second resistors (9a), (9b).

(9a), (9b)... on the insulating group Fi (2a) 1
The first resistor (8r) is arranged in parallel in a column, and all of them are made up of heat-generating resistors, and in the example shown in FIG.

(82), (83)... are arranged in parallel in a row on the insulating board (2a) to form this first resistor (81).

(82) (8i) Only the resistors (9a), (9b), etc. are made up of heat-generating resistors, and these serve as thermal heads to contribute to printing.
(9a).

(9b)... are constructed of ordinary resistors, and the equivalent circuit is as shown in FIG. 2A, and it is easy to understand that the same effects as described above can be obtained.

In the above embodiment, the second resistor is an example in which two resistors (9a) and (9b) are connected in parallel, but it is of course possible to construct this with a single resistor. be. Also, in the above example, the first resistor (81).

(82) (83) ...and the second resistor (9
a).

(9b), (9a), (9b)...
Although the resistance values were all set to the same value, the same effect as described above can be obtained even if the resistance values are different, and the degree of contour enhancement can also be changed by actively changing the resistance value as necessary. I can do it. Furthermore, the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations may be adopted without overcoming the gist of the present invention.

〔Effect of the invention〕

According to the present invention, there is an advantage that a print with sharp image quality that emphasizes horizontal contours can be obtained without using a special circuit.

Description of the FF1I car in the drawings: Figure 1 is a configuration diagram of an embodiment of the thermal head of the present invention; Figures 2 and 3 are diagrams for explaining the present invention;
FIG. 4 is a configuration diagram showing another embodiment of the present invention, FIG. 5 is a partially cutaway perspective view showing an example of a thermal head, and FIG.
7 is a partially cutaway sectional view of the figure, and FIG. 7 is a configuration diagram of an example of a conventional thermal head.

(2a) is an insulating board, (2c) is an individual electrode, (2d) is a common electrode, (3c) is a drive circuit, (81), (82
)... are the first resistors, (9a) and (9b
) is the second resistor.

Figure 1 Figure 2B Figure 3 Other fruits of the present invention a! @N4 claw diagram shown Figure 4 h navy blue substrate Figure 5 Figure 8

Claims (1)

[Claims] The equivalent circuit connects a plurality of first resistors in series, and the first resistor is connected in series.
The 2i-th (i is 0, 1, 2, etc.) connection points of the resistors are connected to the individual drive electrodes, and the 2i+1-th connection points of the first resistor are connected to the second resistors. 1. A thermal head connected to a common electrode through an insulating substrate, wherein at least the first resistor is composed of a heat generating resistor, and the heat generating resistors are sequentially arranged in parallel on an insulating substrate. .