JPH04164658A - Controller for energy to be applied to thermal head - Google Patents

Abstract

PURPOSE:To obtain a stable thermal recording by a method wherein a battery voltage fluctuation caused by an exhaustion of a battery, a printing ratio, and other all load fluctuation is sequentially detected, and a pulse width to be applied is so controlled that a heating element is heated to a required temperature. CONSTITUTION:When a thermal head starts a printing action, a voltage detection part 16 detects a battery voltage. A voltage operation part 17 arithmetically finds a voltage V3 by subtracting a value for a voltage drop when a device is loaded at a maximum from a detected battery voltage V1. Using this value as a reference voltage, a voltage to be applied to a heating element is stabilized by a transistor 18. On the other hand, based on the found voltage V3, a pulse width TC is so set as to ensure a temperature increase of a heating element required to heat thermal recording paper to a color-forming temp. A pulse application is turned ON, and a voltage is applied until the time TC, elapses. When the time TC elapses, the pulse application is turned OFF to complete printing. The stabilizing voltage is set by removing a voltage drop caused by a load fluctuation from a present voltage depending on an exhaustion of battery. Since this voltage is used as a reference when a required pulse width is set and controlled, a stable thermal recording is made available.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for controlling energy applied to a head in a thermal recording device of a facsimile machine, for example, which uses a battery as a power source.

(Prior Art) Some facsimile machines and the like are capable of using both a commercial power source and a built-in battery power source. In the case of battery power, the voltage will drop due to battery consumption.
Also, the terminal voltage fluctuates due to load fluctuations. FIG. 7 shows changes in terminal voltage depending on discharge current and discharge time.

As mentioned above, the voltage of a battery power source fluctuates due to wear and load fluctuations, so - Boat fishing does not have a configuration in which the terminal voltage is directly applied to the load, but rather requires a regulator or DC/DC power source.
The voltage is stabilized using a DC converter.

In a thermal recording device installed in a facsimile machine, a pulse is applied to a heating element of a thermal head, and the generated heat heats a thermal recording paper to a coloring temperature for recording. Conventionally, as shown in Fig. 8, a pulse with a duration of 1 hour Ta is applied to the heating element at a voltage v1 stabilized by a DC/DC converter, etc., and the temperature of the heating element is raised to ta. The temperature of the thermal recording paper that the heating element comes into contact with is raised to pa exceeding the coloring temperature Ca,
I try to always obtain stable color development (recording).

As is clear from FIG. 8(c), as the temperature of the heating element increases, the temperature of the thermal recording paper also increases.
Depending on the characteristics of the thermal recording paper, the color density will be higher. In that case, the color density can be changed by increasing or decreasing the pulse width Ta. Therefore, some facsimile machines are designed to increase the color density when using commercial power, and reduce the width of the applied pulse when using battery power to extend the battery life even if the color density becomes lighter. It has been proposed (see Japanese Utility Model Application Publication No. 198543/1983).

When a battery power source is used in a facsimile device, the battery supplies power not only to the thermal head but also to the entire device (the thermal head consumes 90% or more of the power).

For example, when conveying recording paper, a motor is driven.

Therefore, factors contributing to variations in the power supply voltage during recording are not only load variations due to the printing rate but also load variations of other motors and the like.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, those that use a stabilized power source such as a DC/DC converter are large in size and heavy in weight, and due to the characteristics of the DC/DC converter, switching There are problems such as frequency radio noise.

Furthermore, because the characteristics of the regulator and the like require a heat sink for heat radiation, there is a problem in that the weight and volume further increase.

Furthermore, due to battery consumption, the efficiency of the DC/DC converter has become a problem, and currently the limit is 70 to 80%.

The present invention was made in view of these problems, and
The output of the battery power source is applied almost directly to the thermal head without using a stabilized power source such as a DC/DC converter, and the applied pulse width is controlled while taking battery consumption and load fluctuations into consideration. It is an object of the present invention to provide a thermal head applied energy control device that maintains the color density of thermal recording paper in a saturated region and obtains stable thermal recording.

(Means for Solving the Problems) In order to achieve this object, the present invention firstly (1) applies a pulse to a heating element of a thermal head, and uses the generated heat to heat a thermal recording paper to develop color. a thermal recording means for recording, a battery power supply, a sequential voltage detection means for sequentially detecting the voltage of the battery power supply during printing, and an integrating means for integrating the sequentially detected voltage with respect to time and calculating the energy given to the heating element; It is comprised of a pulse width control means for controlling the applied pulse width so that the calculation result is the temperature rise of the heating element necessary to heat the thermosensitive recording paper to the coloring temperature.

(2) the thermal recording means, a battery power supply, a voltage detection means for detecting the voltage of the battery power supply, and a voltage calculation means for calculating the voltage obtained by subtracting the voltage drop at the maximum load of the device from the detected voltage. , a voltage stabilizing means for stabilizing the voltage applied to the heating element using the calculated voltage as a reference voltage, and a heating element necessary for heating the thermal recording paper to the coloring temperature based on the calculated voltage. and pulse width control means for controlling the applied pulse width so as to obtain a temperature rise of .

Furthermore, (3) it is composed of the thermal recording means, a battery power supply, a voltage detection means for detecting the voltage of the battery power supply, and a means for notifying an abnormality when the detected voltage is out of a predetermined voltage range. Ru. Here, the predetermined voltage range is such that the energy applied to the heating element of the thermal head heats the thermal recording paper to a temperature in the saturation range of color density, taking into account the drop in battery voltage due to load fluctuations. This is the voltage range that provides energy.

(Function) According to the configuration (1) above, fluctuations in battery voltage due to battery consumption, printing rate, and all other load fluctuations are sequentially detected,
In response to this, the applied pulse width is controlled so that the temperature of the heating element increases to the required temperature, so that stable thermosensitive recording can be obtained.

Further, since a stabilized power source such as a DC/DC converter is not used, the device can be made smaller and lighter, have lower noise, and have higher efficiency.

Further, according to the configuration (2), the voltage applied to the heating element is stabilized by using the voltage obtained by subtracting the voltage drop at the maximum load of the device as a reference voltage, and the necessary applied pulse width is set accordingly. Since this is controlled, stable thermal recording can be obtained as in the case (1). In addition, the voltage stabilizing means constructed here is not large-scale like a stabilized power supply such as a DC/DC converter, so
The device can be made smaller, lighter, less noisy, and more efficient.

Furthermore, according to configuration (3), since the thermal recording paper is always heated to the temperature in the saturation range of color density, uneven color development can be minimized even if the battery voltage fluctuates due to load fluctuations. As in the case of (1) and (2), stable thermal recording can be obtained, and the apparatus can be made smaller and lighter, have lower noise, and have higher efficiency.

When the battery voltage falls outside a predetermined voltage range due to overcharging or exhaustion, an abnormality is reported and the battery is replaced.

(Example) Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 shows a thermal head applied energy control device according to an embodiment of the present invention, and is an example applied to a facsimile machine. l is a facsimile machine with battery power supply 2
All power is supplied from

3 is a scanner that reads the original image and extracts image information;
4 is an encoding/decoding unit that encodes image information to be transmitted and decodes received image information; 5 is a plotter that records image information on thermal recording paper, and has a thermal head; A large number of heating element elements are arranged. 6
is a network control device that performs predetermined calling/receiving operations by connecting lines, sending a selection signal that is the destination telephone number, detecting incoming calls, etc. A modem 7 modulates and demodulates image information and transmits the same, and also transmits various procedure signals in transmission control procedures. Reference numeral 8 denotes a communication control section for controlling the network control device 6 and modem 7 to execute facsimile communication. Reference numeral 9 denotes an operation display section, which displays the operating status of the apparatus and allows an operator to perform various operations. IO is a system control section, which includes a microcomputer and various electronic circuits, and controls each section within the facsimile machine. Further, the plotter 5 is controlled to cause the thermal head according to the present invention to perform a heat generating operation.

Reference numeral 11 denotes a power supply unit, which has a battery power supply 2 that supplies power to the entire device.The plotter 5 is directly supplied with battery output, and each part other than the plotter is supplied with a constant voltage by a stabilized power supply 12. Provides digitized output. 13 is a sequential voltage detection unit that sequentially detects the voltage of the battery power supply 2 during printing; 14 is an integrator that is built in the system control unit IO and integrates the sequentially detected voltage with respect to time; calculate. Reference numeral 15 denotes a pulse width control section that controls the applied pulse width so that the calculation result of the integrator 14 becomes the temperature rise of the heating element necessary to heat the thermosensitive recording paper to the coloring temperature.

Next, the operation of this embodiment will be explained using FIGS. 2 and 3. First, in FIG. 2, when the thermal head starts printing, a pulse is applied to the heating element and it starts generating heat (101). At the same time, the sequential voltage detection unit [3] starts sequential detection of the battery voltage (102). Here, the battery voltage is 1 in the pulse-off state, as shown in FIG. 3(a), due to battery consumption up to that point, but drops to V2 due to the printing rate load when the pulse is on. Furthermore, during the pulse-on period, there were load fluctuations in the motor, etc., as shown in Figure 3 (a).
) the voltage fluctuates like this. The voltage that fluctuates in this way is detected one after another, and the integrator 14 integrates it over time to calculate the energy given to the heating element. That is, the calorific value or temperature rise of the heating element is calculated (10
3). Then, it is determined whether the temperature of the heating element has exceeded ta (104), and if it is less than ta, the process returns to step (102) and continues voltage detection and integration for each ΔT. When it is determined that the temperature of the heating element has exceeded t6, the applied pulse is turned off (105), and printing for that heating element is completed. Figure 3(c) shows how the temperature of the heating element increases to , and the thermal recording paper is thereby heated to p, which exceeds the color development temperature C2, and when that temperature is reached, the pulse is turned off. This is what is shown.

Note that the broken line indicates only the printing rate load and no other loads.
This figure shows the temperature rise and pulse-off state when the battery voltage reaches V2.

In this embodiment configured in this way, even if the battery voltage fluctuates due to battery consumption and various loads, the pulse applied to the heating element can be adjusted without using a stabilized power source such as a DC/DC converter. By controlling the width of the heat-sensitive recording paper, it is possible to heat the heat-sensitive recording paper to the color development temperature and obtain stable heat-sensitive recording at all times.

FIG. 4 shows another embodiment of the present invention, in which parts with the same names as those in FIG. 17 is a voltage calculation unit that calculates a voltage obtained by subtracting the voltage drop at the maximum load of the device from the detected voltage, and 18 is a transistor that uses the calculated voltage as a reference voltage 19 to stabilize the voltage applied to the heating element. be. The system control unit 1O includes a pulse width control unit 15 that controls the applied pulse width based on the calculated voltage so as to obtain the temperature rise of the heating element necessary to heat the thermal recording paper to the coloring temperature. ing.

Next, the operation of this embodiment will be explained using FIGS. 5 and 6. In FIG. 5, first, when the thermal head starts printing operation, the voltage detection section 16 detects the battery voltage (
201). Here, the battery voltage is Vl in the pulse-off state, as shown in FIG. 6(a), due to battery consumption up to that point. Therefore, the voltage calculation unit 17 calculates the voltage v3 by subtracting the voltage drop at the maximum load of the device (total of printing load, motor, etc. load) from the detected battery voltage 1 (202), and calculates this voltage v3. The transistor 18 uses the voltage applied to the heating element as a reference voltage.
stabilized by On the other hand, based on the calculated voltage (3), a pulse width T0 is set (2
03). Then, turn on the applied pulse 204), T
A voltage is applied until the voltage reaches 0 (205), and T.

After the elapse of 206, as shown in FIG. 6C, the applied pulse is turned off (206), and printing for that heating element is completed.

In this embodiment configured in this way, the stabilized voltage is set by removing the load fluctuation from the current voltage due to battery consumption, and the necessary pulse width is set and controlled based on that voltage. Stable thermal recording can be obtained.

In the above two embodiments, the applied pulse width was controlled so as to obtain the temperature rise of the heating element necessary to heat the thermal recording paper to the coloring temperature, but the energy applied to the heating element was However, if the thermal recording paper is always heated to the temperature in the saturation range of color density, there is no need to control the applied pulse width.

First, the relationship between the energy applied to the thermal head and the print density will be explained with reference to FIG. 11. Conventionally, a stable voltage was applied to the heating element, so the print density was stable, and in consideration of efficiency, the print density was set within the range of approximately 1.3±0.1. The applied energy was controlled (A region).Then, the print density was 1.4.
If energy is given to the heating element so as to exceed (B
Even if the applied energy is increased, the print density, that is, the color density of the thermal recording paper remains unchanged. This is because the color development has reached a saturated state. This saturation condition is as follows: Environmental temperature and humidity: 5°C, 225% RH, 125°C, 50%
The same appears at RH 135°C, 85% R)l.

Generally, the applied energy is calculated from the following equation.

Q=PT...(2) where, P: Applied power (W/dat) Average resistance value of one R1 heating element (Ω) ■, Applied voltage (
vol) ■0: Driver IC loss voltage (vol) Q: Applied energy (mj/dot) T Applied pulse width (msec) As can be seen from equations (1) and (2), the applied voltage (battery voltage) If it fluctuates, the applied power P will fluctuate and 1 dot
The applied energy per hit varies, but as shown in the example of Fig. 11, the applied energy is 0.35 to 0.5 mj/do.
Even if the temperature varies between t and t, the heating element has reached a saturated state, so sufficiently stable color development can be obtained, and uneven color development can be minimized.

FIG. 9 shows a third embodiment of the present invention based on the above idea, in which 16 is a voltage detection means for detecting the voltage of the battery power source, and 20 is a voltage detection means for detecting the voltage within a predetermined voltage range. This is an abnormality control section that determines that there is an abnormality when it comes off, and displays it on the operation display section 9 via the system control section 10 to notify the operator. Here, the predetermined voltage range means that, as mentioned above, the energy applied to the heating element of the thermal head is capable of increasing the coloring density of the thermal recording paper, taking into account the drop in battery voltage due to load fluctuations. This is the voltage range that provides the energy to heat up to the saturation region temperature.

The voltage falls outside this range when the battery voltage is overcharged or when the voltage drops due to exhaustion.

Figure 1O shows the operation flow of this embodiment. First, before the thermal head starts printing, it is determined whether the battery voltage, which is the applied voltage, has exceeded the specified value due to overcharging ( 301), and determines whether the value has fallen below the specified value due to battery consumption (302). If it is determined to be normal, predetermined recording processing is performed (301).
303). In addition, if it is determined that there is an abnormality, the abnormality control unit 2
In response to the instruction from o, the operation display section 9 will display this information (304).
, notify the operator.

In this embodiment configured as described above, energy is given to the heating element to heat the thermal recording paper to its coloring saturation temperature, taking into account load fluctuations, thereby minimizing uneven coloring. , stable printing can be performed.

(Effects of the Invention) As explained above, according to the present invention, the heating element necessary to heat the thermal recording paper to the coloring temperature takes into consideration battery consumption and load fluctuations, or removes the load fluctuations. By setting and controlling the pulse width that provides a temperature rise of , it is possible to always obtain stable coloring of the thermosensitive recording paper.

Alternatively, since the thermal recording paper is heated to its coloring saturation temperature while taking load fluctuations into consideration, uneven coloring can be minimized and stable printing can be performed.

In addition, since the stabilizing power supply such as the DC/DC converter that was conventionally used can be omitted, the device can be made smaller and lighter.
This has many effects such as lower noise and higher efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention;
Figure 2 is a flowchart showing the same operation, Figure 3 is a diagram showing the relationship between power supply voltage, pulse width, and temperature rise.
5 is a block diagram showing the configuration of another embodiment of the present invention, FIG. 5 is a flowchart showing the same operation, FIG. 6 is a diagram showing the relationship among the power supply voltage, pulse width, and temperature rise, and FIG. 8 shows the relationship between the power supply voltage, pulse width, and temperature rise in the conventional example. FIG. 9 shows the relationship between the power supply voltage, pulse width, and temperature rise in the conventional example. FIG. 10 is a block diagram showing the configuration of another embodiment, FIG. 10 is a flowchart showing the same operation, and FIG. 11 is a diagram showing the relationship between the energy applied to the heating element and the print density. 5...Plotter, 9...Operation display section, lO.
...System control unit, 11...Power supply unit, 12...Stabilized power supply, 13...Sequential voltage detection unit, 14...Integrator, 15...Pulse width control unit, 16... Voltage detection section, 17... Voltage calculation section, 18... Transistor,
19... Reference voltage, 20... Abnormality control section. Patent applicant: Ricoh Co., Ltd. Figure 1/Ginrjj (T) Figure 6 I31! (T) Figure 8 Time (t) Figure 9 Figure 10 Figure 11 LP Karoe 8--(mshidot)

Claims (3)

[Claims] (1) Applying a pulse to the heating element of the thermal head,
Thermal recording means heats the thermal recording paper with the generated heat to color it and record it, the battery power supply, the sequential voltage detection means sequentially detects the voltage of the battery power supply during printing, and the sequentially detected voltage is integrated over time. an integrating means for calculating the energy given to the heating element; and a pulse width control means for controlling the applied pulse width so that the calculation result is the temperature rise of the heating element necessary to heat the thermosensitive recording paper to the coloring temperature. A thermal head applied energy control device comprising: (2) Applying a pulse to the heating element of the thermal head,
A thermal recording means that uses the heat generated to heat the thermal recording paper to develop color and record, a battery power supply, a voltage detection means that detects the voltage of the battery power supply, and a voltage drop at the maximum load of the device from the detected voltage. a voltage calculation means for calculating the subtracted voltage; a voltage stabilization means for stabilizing the voltage applied to the heating element by using the calculated voltage as a reference voltage;
It is characterized by comprising a pulse width control means for controlling the applied pulse width based on the calculated voltage so as to obtain the temperature rise of the heating element necessary to heat the thermosensitive recording paper to the coloring temperature. Thermal head applied energy control device. (3) Applying a pulse to the heating element of the thermal head,
A thermal recording means that heats thermal recording paper using the generated heat to develop color and record; a battery power source; a voltage detection means that detects the voltage of the battery power source; and when the detected voltage is outside a predetermined voltage range. The predetermined voltage range is such that the energy applied to the heating element of the thermal head is such that the energy applied to the heating element of the thermal head does not exceed the temperature of the thermal recording paper, taking into account the drop in battery voltage due to load fluctuations. A thermal head applied energy control device characterized in that the voltage range is set to provide energy for heating up to a temperature in a saturation range of color density.