JPH0839839A - Thermal recording medium processing apparatus - Google Patents

Abstract

PURPOSE:To provide the apparatus estimating the surface temp. of an erasing means and controlling the temp. of the erasing means so as to be capable of erasing the printing on a thermal recording medium. CONSTITUTION:A thermal recording medium processing apparatus is equipped with an erasure means 12 coming into contact with a thermal recording medium heated from a power supply part 6 to thermally erase the data printed on the thermal recording medium, an erasure part 4 equipped with a temp. detection means 13 detecting the temp. of the erasure means 12, an environmental temp. detection means 9 detecting environmental temp., a current quantity detection means 16 detecting the quantity of the current flowing to the erasure means 12 and a control part 7. An estimating operation means 8 estimating the surface temp. of the erasure means 12 coming into contact with the thermal recording medium on the basis of the detection results from the temp. detection means 13, the environmental temp. detection means 9 and the current quantity detection means 16 is provided to the control part 7 and the temp. of the erasure means 12 is controlled on the basis of the estimation result of the estimating operation means 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal recording medium processing apparatus, and more particularly to temperature control of erasing means for thermally erasing print data such as characters and symbols recorded on a thermal recording medium. .

[0002]

2. Description of the Related Art FIG. 4 is a schematic view of a conventional thermal recording medium processing apparatus, FIG. 5 is an enlarged view of the main part thereof, and FIG. 6 is a block diagram of the main part of FIG. In the figure, reference numeral 1 denotes a housing of a thermal recording medium processing apparatus, for example, a magnetic data processing and printing unit 3 for processing and printing magnetic data recorded on a medium 2 having substantially the same size as a telephone card, and a medium 2 An erasing unit 4 for erasing the data and the like recorded in, a storage unit 5 for collecting the unused medium 2, a power source section 6, a control board 7, etc. are provided inside. In addition, the control board 7
Electronic components such as a CPU 8 and an environmental temperature sensor 9 that detects the temperature around the housing 1 are mounted on the. Reference numeral 10 denotes an insertion opening of the medium 2 provided on the side surface of the housing 1 on the magnetic data processing / printing unit 3 side, and 11 denotes the storage unit 5 via the magnetic data processing / printing unit 3 and the erasing unit 4 from the insertion opening 10. This is a transport path for the medium 2 that is in communication.

A heat stamp (plate heating plate) 12 made of a metal material such as a brass plate is installed in the erasing unit 4 as a means for erasing the print on the medium 2, and a heating element provided on the heat stamp 12 ( (Not shown) is a power supply unit 6
Is electrically connected to. Also, heat stamp 12
As shown in FIG. 5, the surface portion of the side contacting the medium 2 has insulating rubber 12a, brass plate 12b and surface rubber 12
It is formed in a three-layer structure of c, and a temperature sensor 13 for detecting the temperature of the brass plate 12b is provided near the brass plate 12b.

The medium 2 is made of a metal material such as aluminum, and a recording layer on which data is printed is formed on a part of the medium 2, which is made of a mixture of an organic polymer and an organic low molecule. The recording layer of this medium 2 is in a transparent state when not printed, and as shown in the diagram of FIG. 7, when the transparent recording layer is heated to a temperature of T ₃ or higher and then cooled to room temperature, it becomes cloudy. Then (→→), the recording layer of the medium 2 is in a printed state. At this time, the maximum temperature is T
If it is ₄ or more, the cloudiness is maximum. Further, when the recording layer of the medium 2 is printed, it is in a white turbid state, and when the white turbid recording layer is heated, it becomes transparent from the temperature T ₁ and becomes the maximum transparent state between the temperatures T _{2 and} T ₃ , When cooled to room temperature, the maximum transparency is maintained and the print is erased (→
→).

When erasing the data printed on the medium 2 in the thermal recording medium processing apparatus thus constructed, first, the medium 2 inserted from the insertion port 10 is sent to the erasing unit 4 through the conveying path 11. Then, the heat stamp 12 heated by the heating element comes into contact with the recording layer portion of the medium 2 and heats it to erase the print. At this time, the CPU 8
The detected temperatures from the environmental temperature sensor 9 and the temperature sensor 13 which are digitalized by the D converters 14 and 15 are received, and the PID (proport
ional, integration and differential) calculation. Next, the CPU 8 sends an ON or OFF signal to the power supply unit 6 based on the calculation result to erase the heat stamp 12 by pulse width modulation control (temperature range from T ₂ to
The temperature is controlled to T ₃ ) and the print is erased by the heat stamp 12. Then, the medium 2 that is no longer used is collected in the storage unit 5 through the transport path 11.

[0006]

Since the conventional thermal recording medium processing apparatus as described above uses the transparent or opaque state, which is the temperature characteristic of the recording layer of the medium 2, to print or erase data. When erasing the print on the medium 2, it is necessary to control the heating temperature of the heat stamp 12 within a erasable temperature range (temperatures T _{2 to} T ₃ ). Therefore, it is conceivable to install a temperature sensor 13 on the surface of the surface rubber 12c in order to accurately detect the surface temperature of the surface rubber 12c that contacts the medium 2.
There is a problem that the uniformity of the surface of 2c cannot be maintained and the medium 2 cannot be erased by printing. Therefore, the heating temperature of the heat stamp 12 is detected by the temperature sensor 13 provided near the brass plate 12b.

However, between the temperature of the brass plate 12b and the surface temperature of the surface rubber 12c that actually contacts the medium 2, a temperature deviation or a time shift (delay) in temperature change occurs, and the housing 1 When the environment where the is installed and the operating conditions change, the temperature deviation also fluctuates correspondingly, but if the time constant of heat transfer is large, even if there is a rapid temperature change, it may be a subtle change depending on the detection location. Could not be detected,
Or it could not be detected at all. For this reason, the surface temperature of the surface rubber 12c that actually contacts the medium 2 deviates from the erasable temperature range, and the surface rubber 12c
If the surface temperature of the medium is higher than the temperature T _3, for example, the recording layer of the medium 2 may become cloudy again, that is, the printed state may not be possible, and the medium 2 may not be erased, or if it is lower than the temperature T _2. However, the recording layer of the medium 2 has just started to be transparent, and there are some deficiencies in print erasing, such as the erasing process ending before the print erasing ends.

The present invention has been made to solve the above-mentioned problems, and thermal recording in which the surface temperature of the erasing means is estimated and the temperature of the erasing means is controlled to a temperature at which printing and erasing of the thermal recording medium can be performed. A media processing device is provided.

[0009]

In a thermal recording medium processing apparatus according to the present invention, an erasing means for erasing data printed on the thermal recording medium by being heated by a power source portion and contacting the thermal recording medium, and the erasing means. The erasing unit including the temperature detecting unit that detects the temperature of the erasing unit, the environmental temperature detecting unit that detects the environmental temperature, the current amount detecting unit that detects the amount of current flowing through the erasing unit, and the control unit. Estimating calculation means for estimating the surface temperature of the erasing means contacting the thermal recording medium based on the detection results from the temperature detecting means, the environmental temperature detecting means and the current amount detecting means is provided, and based on the estimation result of the estimating calculation means. In this way, the temperature of the erasing means is controlled.

[0010]

The temperature detecting means, the environmental temperature detecting means, and the current amount detecting means detect the temperature of the erasing means, the environmental temperature and the amount of current flowing through the erasing means, and based on the detection results, the estimation calculating means provided in the control section The surface temperature of the erasing means that contacts the thermal recording medium is estimated. Then, the control section controls energization to the erasing means based on this estimation result, and further controls the temperature of the erasing means to a temperature at which the print erasing of the thermal recording medium can be carried out, thereby surely erasing the print.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of the essential parts of an embodiment of the present invention. The same parts as those in the conventional example described with reference to FIGS. 4 to 6 are designated by the same reference numerals, and the description thereof will be omitted. In the figure, 16
Is a current amount detection sensor for detecting the amount of current passed through a heating element (not shown) that heats the heat stamp, which is mounted on the control board 7 and is connected via the A / D converter 17 to C
It is electrically connected to PU8. Then, the CPU 8 performs the following based on the detected temperatures from the environmental temperature sensor 9 and the temperature sensor 13 which are digitalized by the A / D converters 14, 15 and 17, and the current amount from the current amount detection sensor 16. The surface temperature of the heat stamp 12 contacting the medium is estimated by various calculations.

FIG. 2 shows a part of the heat stamp 12 and its periphery by a heat circuit, where θ _A is the temperature of the brass plate 12 b of the heat stamp 12, and θ _X is the estimated surface temperature of the heat stamp 12. (Surface rubber 12c), θ _B is the ambient temperature, R _A is the heat transfer resistance of the surface rubber 12c, R _X is the heat dissipation resistance that determines the amount of heat dissipated from the surface rubber 12c, and Q is the heat flow from the heating element. Note that θ _A and θ _B are the temperature sensor 1
3 and the ambient temperature sensor 9, R _A is known.

[0013] The difference theta _A - [theta] _B the temperature theta _A and the ambient temperature theta _B brass plate 12b is heat flow Q, the thermal resistance R _A, than R _X theta _A
It can be expressed as −θ _B = Q ( _RA + R _X ).
Here, the heat flow Q is Q = KP (K is a constant) when the electric power applied to the heating element of the heat stamp 12 is P [W], and this is a constant applied voltage V [V] If the resistance is R [Ω], then Q = K · V ² / R, and since R changes with temperature, Q (R) = K · V ² / R,
Q can be expressed as a function of R. It should be noted that R is obtained from the amount of current I flowing through the heating element detected by the current amount detection sensor 16. Therefore, the heat radiation resistance R _X is R _X =
It can be obtained from the equation (1) of (θ _A −θ _B ) / Q− _RA . Similarly, the surface temperature θ _X is also θ _X −θ _B
= Q _{R X} , therefore θ _X = Q _{R X} −θ _B can be obtained by the equation (2), and the estimated surface temperature θ _X is calculated.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, when the thermal recording medium processing device is powered on, the CPU 8 causes the temperature sensor 13 to operate.
And the temperature θ of the brass plate 12b by the environmental temperature sensor 9.
_A and the environmental temperature θ _B are detected (ST1), and the heat radiation resistance R _X and the surface temperature θ _X are calculated from the above equations (1) and (2) (ST2). The current amount I is a value corresponding to the environmental temperature theta _B is set in advance, the heat storage medium processing device at the time of calculation of the surface temperature theta _X immediately after the power is turned on, a current amount corresponding to the detected environmental temperature theta _B Use the value of I. Then, the erasable temperature range (Fig.
Temperature T _{2 to} T ₃ ) of the target temperature θ _r , which is an intermediate temperature of 70 ° C. to 100 ° C., for example, a minimum set temperature θ _s lower than 85 ° C. by 10 ° C. or more, for example, 65 ° C. to 75 ° C. or more. Until the surface temperature θ _{X of} 12 rises, the CPU 8 sends an ON signal to the power supply unit 6 to energize the heating element to heat the heat stamp 12 regardless of the pulse width modulation control (ST3, 4).

When the surface temperature θ _X becomes higher than the minimum set temperature θ _s , the CPU 8 sends an OFF signal to the power source section 6 to stop heating the heat stamp 12 irrelevant to the pulse width modulation control (ST3, 5). Then, the CPU 8 calculates the pulse width P _w by performing the PID calculation (ST6), the surface temperature θ _X is maintained within the erasable temperature range (temperatures T _{2 to} T ₃ ), and is closer to the target temperature θ _r. So that the pulse width modulation control is started. Then, the pulse width P _w is compared with the count value C for counting the period A (about several seconds) of the pulse width modulation control (ST7). If the count value C is less than the pulse width P _w , the CPU 8 causes the power supply An ON signal is sent to the section 6 to energize the heating element to heat the heat stamp 12 (ST8, 9, 10). At this time, the current amount detection sensor 1
6 detects the amount of current I flowing through the heating element, and the CPU 8 holds this value (ST12). Further, when the count value C becomes larger than the pulse width P _w , an OFF signal is sent to the power supply unit 6 to stop the energization of the heating element and the heating of the heat stamp 12 until the period A passes (ST11). ，
9, 10). Then, returning to ST1, the heat stamp 12 is applied so that the surface temperature θ _X becomes closer to the target temperature θ _r.
Repeat the temperature control of. At this time, the surface temperature θ _{X and the} like are calculated using the value of the current amount I detected by the current amount detection sensor 16 and held by the CPU 8.

On the other hand, when an instruction to erase the print of the medium inserted in the housing of the thermal recording medium processing device is issued, the medium in the housing is conveyed to the erasing unit 4 and is in the erasable temperature range (temperature T ₂ The print erasing process is performed by the heat stamp 12 whose temperature is controlled to T ₃ ). Then, the medium that is no longer used is transported to the storage unit and collected.

As described above, the pulse width modulation control is performed based on the heat radiation resistance R _X and the surface temperature θ _X calculated from the equations (1) and (2) and the calculation result calculated by the PID calculation. , Surface temperature of heat stamp 12 θ _X
The temperature can be controlled within the erasable temperature range (temperatures T _{2 to} T ₃ ), and the medium can be surely erased. Further, since the surface temperature θ _X of the heat stamp 12 can be easily estimated by a simple calculation, a complicated calculation or the like for increasing the accuracy of temperature control becomes unnecessary,
The calculation is simplified, the calculation time of the CPU 8 can be shortened, and highly accurate temperature control can be quickly performed.

[0018]

As described above, in the thermal recording medium processing apparatus according to the present invention, the erasing means for erasing the data printed on the thermal recording medium by being heated by the power source portion and contacting the thermal recording medium, and the erasing means. An erasing unit equipped with a temperature detecting means for detecting the temperature of, an environmental temperature detecting means for detecting the environmental temperature,
Current amount detecting means for detecting the amount of current flowing through the erasing means,
A control unit, and the control unit is provided with an estimation calculation unit that estimates the surface temperature of the erasing unit that contacts the thermal recording medium based on the detection results from the temperature detection unit, the environmental temperature detection unit, and the current amount detection unit, Since the temperature of the erasing means is controlled based on the estimation result of the estimation calculating means, even if the temperature of the erasing means changes due to the environment or operating conditions, it is possible to perform highly accurate temperature control corresponding to it. In addition, it is possible to reliably perform print erasure by preventing defects in print erasure of the thermal recording medium.

[Brief description of drawings]

FIG. 1 is a block diagram of an essential part of an embodiment of the present invention.

FIG. 2 is a thermal circuit diagram of a part of a heat stamp and its periphery according to an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 4 is a schematic diagram of a conventional thermal recording medium processing device.

5 is an enlarged view of a main part of FIG.

FIG. 6 is a block diagram of a main part of FIG.

FIG. 7 is a diagram showing temperature characteristics of a thermal recording medium.

[Explanation of symbols]

2 medium 4 erasing unit 6 power supply section 7 control board 8 CPU 9 environment temperature sensor 12 heat stamp 13 temperature sensor 16 current amount detection sensor θ _X surface temperature

Claims (1)

[Claims] 1. An erasing unit comprising: an erasing unit which is heated by a power supply unit and abuts on a thermal recording medium to thermally erase data printed on the thermal recording medium; and an erasing unit which detects a temperature of the erasing unit. An environmental temperature detecting unit for detecting an environmental temperature; a current amount detecting unit for detecting an amount of current flowing through the erasing unit; and a control unit, wherein the control unit includes the temperature detecting unit, the environmental temperature detecting unit, and the current amount. Estimating calculation means for estimating the surface temperature of the erasing means contacting the thermal recording medium based on the detection result from the detecting means is provided, and the temperature of the erasing means is controlled based on the estimation result of the estimating calculation means. Characteristic thermal recording medium processing device.