JPS60201968A - Thermal head - Google Patents

Abstract

PURPOSE:To make uniform the recorded density, by a construction wherein an individual conductor having a bonding terminal end face effectively shortened to the side of a central part of an IC is provided with a conductor resistance correcting region longer than that of an adjacent individual conductor having an effectively longer bonding terminal. CONSTITUTION:In the conductor resistance correcting regions (n) of the individual conductors L1-Lm connected respectively to heating resistors R1-Rm, the length of the ragions (n) is not sequentially monotonously decreased in the direction from the bonding terminal T1 or Tm toward the bonding terminal Tp or Tg, but is locally increased in some areas, and the lengths of the bonding terminals T1-Tm connected to the individual conductors L1-Lm corresponding to the areas are gradually or monotonously reduced to the side of the center of the IC. Accordingly, resistances of the conductors L1-Lm can be made uniform, whereby the density of images recorded by the thermal head can be made uniform, and the size of the head can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal conductor, and particularly to the shape of its conductor.

A conventional example will be described below with reference to the drawings. FIG. 1 shows an example of a plan view of essential parts of a thermal head for a line printer. In the same figure, a heating resistor s-R, which is connected to a single driver IC, is connected to a conductor O1-- branched into a rectangular shape from a common electrode O. A large number of individual conductors L1 to Lm are connected to the other end of the resistor, and these individual conductors are formed to extend to the bonding terminals T, to Tm of (1)0. The basic structure is a zero-wire structure in which ICs are mounted on the individual conductors via an insulating layer, and many are arranged on a board.
It is de.

Now, an example of an A4 size thermal head having a total number of resistors of 1728 and a resolution of 8 resistors/mm will be explained. When a single unit 0 drives all 32 resistors (i.e. m
= 32), a total of 54 ICs are placed on the board in 4.0 ms.

Furthermore, when m=54, a total of 27 ICs are arranged on the substrate at a pitch of 8.0 m.

Here, m, , = 32, the width of the resistors 几 and ~Rm are each 0.115 m, and the interval between the resistors i is 0.01 mm.
Then, the distance indicated by 'a' is 3.99 wa*.

Furthermore, the distance indicated by 'b' is 3.90 m, assuming that the distance between the bonding terminals of adjacent ICs is f 0.1 mm.
It becomes +. By the way, the dimensions (2/) of the bonding terminals T1 to Tm are preferably 0.5 m, so the width of the individual conductors L1 to Lm in the area indicated by 'S' is (3,9+m-0,5mX2). )÷0.091 out of 32
m or less. In other words, if the baton interval i0.01+oa, the baton width is approximately 0.08 ms.
, -am is approximately 70% of the individual conductor width of 0.115 in the region in contact with am. Bonding terminal Tpe T +a
+'l”g k Ta y +Tm f T31
Then, the narrow conductor width region S' is 'rta and T
8. is the longest, T1 and T8. is the shortest, so the conductor resistance of Ll and L31 is L16. The value is several ohms lower than the conductor resistance of Ll7. For example, let us assume that the difference in conductor resistance is 5Ω, and the resistance value of ■Mo, ~Rm is 300Ω
Assuming that, the resistance deviation of 5Ω is 0.0 at the rated operation with a power supply voltage of 12V. This results in a power deviation of OIW, which causes a periodic density deviation in the thermal and dot print density. i.e. 5
The print density recorded by the resistor connected to the parts corresponding to the four IO terminals 'rp and 'rg is the lowest.
The print density recorded by the resistor connected to the portion corresponding to Tl1TIn is highest.

As a method to eliminate such drawbacks, for example, the patent application
8-185428, a method is generally used to equalize the conductor resistances of the four-tube bodies L1 to Lm. That is, the individual conductors I'1-Lt connected to the resistors It, ~H, m
n is the width of the button in contact with the resistance part (for example, 0,
A conductor resistance correction region 'n' having a width smaller than 115 vran) is provided, and the batten width of the region 'n/ can be, for example, 0.08 mm in the above example. For example, in the case of the individual conductors L1 and LIll connected to T1 and Tm, this region n' is the longest, and as it approaches Tp or Tg from %TI or Tm, it is sequentially shortened to single J11. In the case of , the conductor resistance deviation of each solid conductor L1 to Lm can be made uniform to be equal to or less than tiΩ by setting it to the shortest length.

However, m=54. In other words, when a single IC drives 64 resistors, the dimension indicated by 'n' becomes long,
As a result, the inside of the thermal board becomes large, and the cost of manufactured thermal heads becomes high. For example, the dimensional difference between adjacent resistors in % n /'e 0.3
van, the 117 dimension when m=32 is 0.
3mX (32/2 1) will be about 4.5fl, whereas the 101 dimension in the case of m=64 is 0.3w+nX (
64/2-1) It was very wide, about 9.3mm in the middle.

Therefore, the present invention was made to eliminate the above-mentioned drawbacks, and it is possible to make the conductor resistances of the conductors L1 to L+n uniform, thereby making the recording density of the thermal and decoding uniform, and to use a small and inexpensive thermal head. It provides:

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows T
, or instead of monotonically shortening the dimension of 'n' as it approaches Tp or Tg from Tan, a region is provided where the dimension is locally lengthened, and an individual conductor corresponding to that region is provided. The bonding terminal portion connected to the IC has a metal step shape or is monotonically shortened toward the center of the IC.

That is, the distance indicated by 'a' is 7.99 m, assuming that the widths of R1 to I(, m in the above example are each 0.115 mm).

In addition, the dimensions of the terminal length required for bonding are each set to 0.
．． 5 pieces, total pitch of individual conductors in -5' region is 0.09
If m, the distance indicated by 'b' is 6 in b (0,091 seagull x 64 + 0.5 fight x 2) in TI and Tan parts.
．． 8 vm t'x ru a t 7'c 'rp (P
= 32)
2I+1III+〇, 5 cabinets x 2) = 3m. Therefore, as the individual conductor moves from the river to the Tp section or from the Tm to the Tg section, that is, as the individual conductor approaches the center side of mounting work 0, the distance of the bonding terminal becomes c=
(bb')/2=(6,83)+m/2=1.9 It is possible to shorten the cage. By shortening the bonding terminal metal in this way, the conductor resistance of the individual conductors L3 to LI11-2 becomes substantially lower, and therefore the dimensions of the conductor resistance correction area of % n / are partially adjusted to make the conductor resistance uniform. It becomes necessary to lengthen the length. "For example, when an individual conductor moves from T, to T, or from T+n-1 to Tm-2, the terminals of T3 and Tm-z will become 0 as well as T and Tm-1.
．． It can be made as short as 4 screams. In this case, the conductor resistance of the individual conductors L3 and Lm-2, and Lm-1
, the dimension of conductor resistance complementary region n' is sL for L3 and Lllll-2 individual conductors.
2 and Lllll-1 individual conductors need to be approximately 0.2 times longer.

Therefore, in the case of individual conductors whose bonding terminals have the same end face, when the individual conductors move from Ll to L4, or from L8 to L4, the dimensions of the corresponding 'n' regions are each about 0.3W. It becomes shorter. However, the bonding terminal becomes shorter.

When the individual conductor moves from L3 to L3 or from L4 to Lll, the dimensions of the conductor resistance correction area 'n/ become longer at L3 and the 3rd part, and conversely become longer by about 0.2 degrees than the 5th part. The need arises.

When m=64, if the bonding terminals T1 to Tp t or Tg - Tm f are shortened in 5 steps, the dimensions of the conductor resistance correction area are 0.3 x (64/2-5) -0,
It can be approximately 2X4=7.3s+m. That is, assuming that the substrate width of the thermal head is about t-25 m, the thermal head of the present invention can be made about 8 inches smaller in width than the substrate, thereby providing a uniform printing density.

(The shape of the n/ region is not particularly limited to the orthogonal shape as shown in Fig. 2. For example, it can be any shape of an oblique tube, and the width of the button can also be of any value. can do.

The present invention improves the recording resolution by reducing the conductor width.
The effect becomes more noticeable when the film thickness of the individual conductors is reduced, that is, when the conductor resistance per unit length is increased.

Since the present invention exhibits the above-mentioned effects, the material and film thickness of the individual conductors, the batten width, the number of resistors that can be driven by a single IC,
It goes without saying that there are no restrictions on the step or number of steps to shorten the bonding terminal metal, or the method for shortening it (stepwise or monotonically decreasing) 1. The resolution of the heating resistor, etc. The use of the do is not particularly limited, and it can naturally be used for lines, dos, serials, dos, etc. Furthermore, the present invention can be practiced by making the bonding terminal surfaces the same and by sequentially shortening the bonding wires to effectively shorten the bonding terminal surfaces. Furthermore, a conductor may be provided in an arbitrary shape for grounding the recording current flowing through the heating resistor in the gap (0 part) caused by the short bonding terminal.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the main parts of a conventional thermal head. FIG. 2 is a plan view showing the main parts of a thermal device according to an embodiment of the present invention. 1...C(a,~On) common electrode, 2...
・・・几、〜Rm (Heating resistor C 3...L
, ~Lm (individual conductor), 4...T1-Tm
(bonding terminal), 5...S area (narrow conductor width area), 6...n area (conductor resistance correction area)

Claims (1)

[Claims] In an individual conductor having a conductor resistance correction region that is connected to the heating resistor and extends to the bonding terminal of the IO, and has a conductor resistance correction region whose batten width is narrower than the portion in contact with the resistor, the end face of the bonding terminal is I to be installed
In the individual conductor formed to be effectively short toward the center of C, the conductor resistance correction region on the individual conductor having an adjacent effectively long bonding terminal is also formed to have a long dimension. Hey, do.