JPH07119119B2 - Method of estimating recorded pattern density at high and low temperature of thermal printer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer used for recording patterns such as characters and images in a computer or a facsimile, and particularly recording when an ambient temperature (ambient temperature) becomes higher or lower than room temperature. Method for estimating the density of a patterned pattern.

[0002]

2. Description of the Related Art The principle structure of a thermal printer is shown in FIG. As shown in this figure, the thermal printer comprises a thermal head 1, a signal generator 2, and a DC power supply 3. The thermal head 1 is provided with minute low antibodies having a size of about 0.1 mm arranged in a matrix, and is selectively lowered by a direct current received from a direct current power source 3 according to a recording pattern output from the signal generator 2. Heat the antibody.

The thermal paper 4 is formed by applying a white coloring layer 6 to the surface of the base paper 5 at room temperature, and when the thermal head 1 contacts the coloring layer 6, the coloring layer 6 instantly develops color. The color of the coloring layer 6 at the colored portion is black, red, blue or the like, and the color is determined by the material of the coloring layer 6. In FIG. 3, the color-developed portion is shown as the same area as the entire front surface of the thermal head 1 as the color-developed portion 7. However, the actual color-developed portion is only the portion in contact with the heated low antibody. The pattern is recorded on the thermal paper 4 as a recording pattern. The recording pattern is a character or an image generated by the signal generator 2.

The degree of color development in the color development section 7 is the density of the recording pattern. The density is determined by the temperature of the thermal head 1 and substantially depends on the thermal energy applied to the thermal head 1. Even if the thermal energy is the same, it varies considerably depending on the temperature of the environment in which the thermal printer is placed. Therefore, conventionally, in order to confirm the density of a recording pattern at an environmental temperature higher or lower than room temperature, the thermal printer is put in a thermostatic bath, the pattern is actually recorded on the thermal paper, and the density of the pattern is examined. It was

[0005]

A thermal printer is housed in a constant temperature bath, and the temperature inside the bath is set to a predetermined temperature (for example, -2).
It takes a considerable time (for example, 1 hour) to set the temperature to 0 ° C. Moreover, the reliability of the thermal printer may be deteriorated by applying such a rapid temperature stress.

As described above, the conventional method for confirming the density of the recording pattern when the thermal printer is at a high temperature or a low temperature has problems to be solved in terms of work efficiency and reliability of the thermal printer. An object of the present invention is to solve the problems in the conventional method, to easily know the density of a recording pattern by a thermal printer in a high temperature or low temperature environment, and to prevent the reliability of the thermal printer from being impaired. In offer.

[0007]

Means for Solving the Problems The means provided by the present invention for solving the above-described problems are characters printed by a thermal head of a thermal printer on a paper in an environment of a temperature T _HL higher or lower than room temperature T _M. a method of estimating the concentration of pattern or image, the temperature of the thermal head when recording at a normal temperature environment T _K, the voltage applied to the thermal head for recording in the normal temperature and V Then, V '= {(T _HL + T _K -2 T _M ) / (T _K -T _M )} ^1/2 · V is applied to the thermal head in a room temperature environment with a voltage V'calculated. Record the pattern on the paper,
A method for estimating a print pattern density at high and low temperatures of a thermal printer, which comprises estimating the pattern density recorded on the paper at the temperature T _{HL at} which the thermal printer will record the pattern density on the paper. Is.

[0008]

In the present invention, the density of the recording pattern in the high temperature or low temperature environment is estimated by simulating the density of the recording pattern in the high temperature or low temperature environment in the normal temperature environment.

FIG. 1 shows the relationship between the temperature of the thermal head and the thermal energy supplied to the thermal head for an environment of room temperature T _M and an extremely hot environment of high temperature or low temperature T _HL (T _HL is low temperature in the figure). FIG. In FIG., T _M: normal temperature T _HL: temperature T _K of the environment is higher or lower than the atmospheric temperature T _M: constant voltage V is applied to the thermal head in an environment of normal temperature T _M, when heated by the current (more specifically, each minute low antibody following the same are arranged in a matrix in the thermal head..) the thermal head to reach the temperature T _'k of: applying a hot or cold T _HL constant voltage V is a thermal head in an environment The temperature of the thermal head that is reached when heated by an electric current W: The thermal energy consumed to heat the thermal head when a steady voltage V is applied to the thermal head W ′: In an environment of room temperature T _M the temperature of the thermal head is a thermal energy consumed to heat the T _'K. Then, when the voltage to be applied to the thermal head to generate the thermal energy of V ′: W ′ in the thermal head is R: the electrical resistance of the thermal head, the following equation is established. W = V ² / R ………………………………………………………… (1) W ′ = V ′ ² / R ……………………………… _{........................... (2) T K -T M} = W · k ......................................................... (3) T 'K -T HL = W · k ......................................................... (4) T 'K -T M = W' · k .......................................... (5) However, k is a constant. From the above formulas (1) to (5), V ′
The When determined for T _HL, V '= a _{{(T HL + T K -2T} M) / (T K -T M)} 1/2 · V ... (6).

FIG. 2 is a diagram showing the relationship between T _HL and _V'calculated by the equation (6). As it is clear from the noted above, 'by setting the temperature of the thermal head T' the voltage applied to the head remain environment at room temperature T _M V which is obtained by the equation (6) to the _K You can Since the density of the recording pattern is determined by the temperature of the thermal head, the voltage applied to the thermal head is set to V ′ to record the pattern, and the density of the recording pattern can be estimated as the density of the recording pattern at the environmental temperature _THL .

[0011]

EXAMPLE An example of estimating the density of a recording pattern by applying the present invention will be described. In the thermal printer used in this embodiment, the electric resistance R of the thermal head is 240Ω,
When the steady voltage V applied to the thermal head is 14.6 [volts], the designed normal temperature T _M is 25 ° C., and the steady voltage V is applied to the thermal head in the environment of the normal temperature T _M , the thermal head reaches. It is assumed that the temperature T _K is 150 ° C.
When this thermal printer is placed in an environment of a temperature of −20 ° C., the print density of the thermal printer (here, the recording pattern is assumed to be characters) is estimated. That is, the above-mentioned T _HL is −20 ° C. Then, by substituting T _K = 150 ° C. T _M = 25 ° C. T _HL = −20 ° C. V = 14.6 [V] into the above-mentioned formula (6), V ′ is obtained and V ′ ≈11.7. [V].

Therefore, when a direct current voltage of 11.7 V of the thermal head is applied to the thermal paper in an environment of room temperature of 25 ° C. to print on the thermal paper, the steady voltage V is applied to the thermal head at an environmental temperature of −20 ° C. It can be estimated that it is the print density at that time.

In this embodiment, since it is not necessary to store the thermal printer in a thermostatic chamber, the print density of the thermal printer in a low temperature environment of -20 ° C can be easily estimated, and since thermal stress is not applied, the quality of the thermal printer is improved. There is no possibility of decreasing the reliability and degrading the reliability.

[0014]

As described in detail above, according to the present invention, it is possible to easily know the density of a recording pattern by a thermal printer in a high temperature or low temperature environment, and the reliability of the thermal printer may be impaired. It can provide a method that does not exist at all.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a temperature when a thermal head is heated and thermal energy applied to the thermal head.

FIG. 2 is a diagram showing a relationship between an environmental temperature and a voltage to be applied to a thermal head for estimating a temperature of a recording pattern at the environmental temperature.

FIG. 3 is a conceptual diagram showing a schematic configuration of a thermal printer.

[Explanation of symbols]

 1 Thermal Head 2 Signal Generation Section 3 DC Power Supply 4 Thermal Paper 5 Base Paper 6 Coloring Layer 7 Coloring Section

Claims (1)

[Claims] 1. A method for estimating the density of a character or image pattern recorded on a paper by a thermal head of a thermal printer in an environment of a temperature T _HL higher or lower than a room temperature T _M , wherein Set the temperature of the thermal head to T
_K , where V is the voltage applied to the thermal head for recording in the room temperature environment, V ′ = {(T _HL + T _K −2 T _M ) / (T _K −T _M )} ^1/2. The voltage V'calculated by the formula V is applied to the thermal head at room temperature to record a pattern on the paper,
A method for estimating a print pattern density at high and low temperatures of a thermal printer, which comprises estimating the pattern density recorded on the paper at the temperature T _{HL at} which the thermal printer will record the pattern density on the paper. .