JPH05138985A - Heater control device of printer or the like - Google Patents

Abstract

PURPOSE:To provide a heater control device on a printer or the like which does not allow a large amount of electric current to flow to the printer upon turn ON of power, if the resistance value of a thermal element on the printer changes with time. CONSTITUTION:If a power supply is turned ON, each heater is energized sequentially for three seconds (S11), and a soaring temperature is detected based on a signal from a thermister installed on each heater (S12). Then the difference between a detected temperature and a previously set temperature for each heater is calculated (S13), and an energization time for each heater and its timing are determined. Further, temperature control is performed using an ON/OFF manipulation process (S18) after the detected temperature of each heater coincides with the previously set temperature (S17).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater control device for a printer or the like having a plurality of heating units, which detects the temperature of each heating element and determines the energization timing.

[0002]

2. Description of the Related Art Conventionally, in a printer or the like which uses a heat-fusible solid ink which is a solid at room temperature and becomes a liquid when heated and melted, it is necessary to provide heater heat modules at a plurality of locations because of the above characteristics of the ink. There is. That is, in addition to the heater for heating the print head, a heater for heating the ink storage portion in order to constantly hold and melt the ink, and also to stably fix the ink on the plain paper at the time of printing. Therefore, it has a heater for heating the printing platen.

Further, in addition to the above heater, a heater is provided for performing reheating treatment in order to improve the translucency of the ink at the printing portion when printing on a transparent sheet for overhead projector (hereinafter referred to as OHP film). ing. This is the same condition as when printing on plain paper.
When printing on a HP film, due to the characteristics of the ink used, the temperature of the ink drops and the ink droplets solidify in a swelled shape on the film surface, which is projected by an overhead projector in this state. In this case, the amount of transmitted light at the printed portion is small, so that the coloration of the projected image on the screen becomes insufficient. Therefore, in order to flatten the surface of the ink droplet, reheating treatment is performed after printing.

Each of the above thermal modules comprises a heating element, a metal member heated by the heating element (hereinafter referred to as a heated member), and a thermistor for detecting the temperature of the heated member. However, since the volume of the member to be heated and the set temperature condition in each thermal module are different, the optimum heating element in each thermal module is required to have a different resistance value. As the heating element, a planar heating element that is easy to manufacture and inexpensive is widely used. In this planar heating element, a current-carrying pattern is formed in parallel with a flexible film printed circuit board surface, and a carbon resistor paste is applied by a silk screen printing method or the like so as to cover the current-carrying pattern. The resistance heating portion is formed by firing.

Further, it is known that the above-mentioned sheet heating element has its resistance value reduced with time when it is used for a long time under a high temperature condition. Therefore, as a method of controlling the temperature of the heating element, a method of maintaining an optimum temperature is generally performed by determining the power supply timing to the heating element based on the temperature detected by the temperature detecting means such as a thermistor. Has been. With such a control method, the temperature of the heating element is controlled to be substantially constant even when the resistance value of the heating element changes with time as described above.

[0006]

However, in the above temperature control method, a constant voltage is continuously applied to the heating element from the initial stage of the heat treatment to the lapse of time. During energization when the resistance value of the heating element decreases, a larger current flows through the heating element than in the initial state. Therefore, for example, in a printer including a plurality of heat generating modules described above, when the resistance values of all the heat generating elements included in the printer are reduced due to aging, when the printer is started, the current flowing through the entire printer is reduced. Compared with the current value at the time of assembling the printer, a larger current will flow, and the value may exceed the current supply capability of the power supply unit of the printer.

As a countermeasure against the above, the resistance value after aging is estimated for all the heating elements provided, and a power supply unit having a current supply capacity corresponding to the maximum resistance value obtained by summing the resistance values is selected. Although it may be possible to provide such a device, the size of the power supply unit of the printer is increased, and accordingly, the size of the entire printer is increased. Moreover, after the temperature of the member to be heated has risen to the optimum temperature, a small value is sufficient for the current required to maintain the optimum temperature. However, it cannot be said that the capacity of the power supply unit is being used effectively. In order to solve the above-mentioned problem, the present invention prevents an excessive current from flowing when the power of the printer or the like is turned on even when the resistance value of a heating element provided in the printer or the like changes with time. An object is to provide a heater control device in a printer or the like.

[0008]

To achieve the above object, a heater control device in a printer or the like according to the present invention comprises a heated member heated by a heating element and a temperature detecting means for detecting the temperature of the heated member. And a plurality of thermal modules each having a power control unit that controls power supply to the heating element, and a determination command unit that commands a power supply time to the power control unit based on a signal from each temperature detection unit. The determination command section has means for deciding the timing of energization to each heating element based on the temperature rise value detected by each temperature detection means after energizing each heating element for a predetermined time at the start of energization. Is.

[0009]

According to the above construction, when a plurality of places are heated in a printer or the like, the temperature rise value of each heated member heated by the heating element after being energized for a predetermined time at the start of energization Is detected by the temperature detecting means, and the determination command section determines an appropriate energization timing to each heating element based on the detected temperature rise value, so that stable temperature control can always be performed by the small capacity power source. ..

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a heater control device of the present invention is provided in a printer will be described below with reference to the drawings. FIG. 1 is a sectional view of a printer 1 according to this embodiment. In the figure, below the printer 1, a paper feed cassette 53, in which a large number of standard-size paper A is stacked, is detachably mounted. An automatic paper feed roller 55 is arranged above the mounting position of the paper feed cassette 53. The automatic sheet feeding roller 55 separates the sheets A stacked in the sheet feeding cassette 53 one by one from the uppermost sheet and supplies them to the printer 1.
A guide plate 59a is arranged at a position corresponding to an upstream portion of the paper feed cassette 53 inside the printer 1 on the paper conveyance path, and the paper A supplied into the apparatus is arranged at the center of the printer 1. The print section 65 is guided.

The upstream paper feed roller 6 is provided on the upstream side of the printing section 65 in the paper transport direction (hereinafter, simply referred to as the upstream side).
1a is a downstream side of the printing unit 65 in the sheet conveying direction (hereinafter,
A downstream paper feed roller 61b is arranged on the (downstream side) side. The pair of upstream paper feed roller 61a and downstream paper feed roller 61b are rotationally driven by a paper feed motor (not shown). The upstream paper feed roller 61a and the downstream paper feed roller 61b are in contact with a rotatable upstream pinch roller 63a and a downstream pinch roller 63b, respectively, at a predetermined pressure. The upstream paper feed roller 61a includes the upstream pinch roller 63a and the downstream paper feed roller 61a. The feed roller 61b rotates while sandwiching the paper between it and the downstream pinch roller 63b, and conveys the paper.

The print unit 65 has a print head 67 for printing characters and figures on a sheet, and the print head 67.
A platen 69 for supporting the paper is provided at a position opposed to the print head 6, and the drive device drives the print head 6 in accordance with data input from an external device such as a personal computer.
Characters and figures are printed on the paper by driving 7. Further, the printer 1 uses a heat-fusible solid ink that is solid at room temperature and becomes a liquid when heated and melted, and is attached to the platen 69 in order to stably attach the ink on the paper at the time of printing. By energizing the attached resistance heating element heater 68, it is constantly heated to a constant temperature (for example, 65 ° C.). The configuration of the drive unit for the printing unit 65, the control procedure, and the like are well known in the art, and thus detailed description thereof will be omitted.

The upstream paper feed roller 61a and the printing section 65
A second detector 79 is provided between them. This second
The detector 79 is composed of a conventionally well-known photo sensor,
The presence / absence of a sheet conveyed by the upstream sheet feed roller 61a and the type of the sheet are detected. A paper discharge roller 73 is arranged downstream of the downstream paper feed roller 61b, and a pair of guide plates 71 is arranged between the downstream paper feed roller 61b and the paper discharge roller 73. Then, the paper on which characters and the like are printed by the printing unit 65 is conveyed to the paper discharge roller 73 along the guide plate 71. The conveyed sheet is ejected in the direction D by the rotation of the sheet ejection roller 73,
4 are stacked on top of each other.

On the other hand, when the second detector 79 detects that the sheet being conveyed is an OHP film, the diverter gate 64 arranged on the downstream side of the downstream sheet feed roller 61b causes the sheet to move. The transport route of is switched to the C direction. As a result, the printed OHP film is guided to the reheating processing unit having the reheating unit 72. The OHP film guided to the reheat processing unit is guided to the OHP feed roller 78 a along the OHP guide plate 70, and the assist roller 78 b located downstream of the reheat platen 75.
And the OHP feed roller 78a, the guide plate 7 is pressed against the reheating platen 75 at a constant pressure.
1 and then discharged in the direction D in the above-described transport path in the same manner as the sheets other than the OHP film.
4 are stacked on top of each other. The reheating platen 75 is provided with a heating element (heater) 76.

When printing on a paper B having a size different from that of the paper A provided in the paper feed cassette 53, the user of the printer 1 himself / herself uses the manual insertion slot 54 to print the paper one by one. It can be supplied inside. A manual paper feed roller 56, which is driven to rotate by a manual paper feed motor (not shown), is arranged above the paper feed cassette 53. The manual paper feed roller 56 has a rotatable pinch roller 57. They are in contact with each other with a predetermined pressure. The manual paper feed roller 56 rotates while nipping the paper with the pinch roller 57 and feeds the paper.

On the upstream side of the manual feed roller 56, there is a first
A detector 77 is provided, and the presence or absence of the sheet B manually inserted is detected by the first detector 77. This first detector 77 is also the second detector 79.
Similarly to the above, it is composed of a well-known photo sensor. A guide plate 59b is arranged on the downstream side of the manual paper feed roller 56, and guides the paper B supplied into the printer 1 to the upstream paper feed roller 61a and the upstream pinch roller 63a.

In addition, an ink holding portion 80 for storing and holding the liquid ink 82 which is constantly heated and melted is provided at the center of the printer 1. The ink holding portion 80 heats the ink storage tank 81 formed of a metal member and the ink storage tank 81.
Heating element (heater) 83 attached to the bottom surface of the ink and the ink 8
When the remaining amount of 2 becomes small, the opening / closing lid 85 is opened and closed to supply the solid ink. The ink storage tank 81 and the print head 67 are connected by an ink supply tube 84,
When the remaining amount of ink inside the print head 67 becomes small,
Ink is replenished to the print head 67 from the ink holding portion 80 via the ink supply tube 84.

Next, the temperature control of the heat module will be described. FIG. 2 is a block diagram showing a thermal module included in the heater control device in the printer according to the present embodiment and a configuration of the heater control device. As the heated member,
It includes a platen 69, a reheating platen 75, and an ink storage tank 81. Heaters 68, 76, 83 that can generate the optimum heat generation amount are provided for the respective members to be heated.
Is attached.

On the other hand, a thermistor for temperature detection is attached to each of the heated members. That is, the temperature detecting thermistor 21 is attached to the platen 69, the temperature detecting thermistor 22 is attached to the reheating platen 75, and the temperature detecting thermistor 23 is attached to the ink storage tank 81. The heaters 68, 76, 83 pass through the power control units 41, 42, 43, respectively, and a determination command unit (CPU)
This determination command unit (CPU) 10 is connected to the CPU 10.
Is a control command (C1, C2, C3) to turn on / off power supply to each heater based on a signal from a temperature detecting thermistor attached to each member to be heated.
Is to be emitted.

Next, the temperature control procedure according to this embodiment will be described. FIG. 3 is a flow chart showing an example of the temperature control procedure of the heater control device in the present embodiment, FIG. 4 is a diagram showing the timing of control command signals output to each power control unit, and FIG. 5 is a flow chart shown in FIG. It is the figure which showed the mode of the temperature rise of the to-be-heated member when controlling a heater.

First, when the power is turned on, the printers of the printers 68, 76 and 83 are operated for a fixed time (for example, 3 seconds).
Are sequentially energized (S11), and the temperature detecting thermistors 21, 22, 23 attached to the heaters 68, 76, 83, respectively.
Based on the temperature rise electric signal from the
U) 10 checks the temperature rise (S12). This first constant-time energization corresponds to the period T1 in FIG. Next, the result of this check, that is, the difference between the detected temperature and the desired set temperature preset for each heater is calculated (S13) to determine the energization time and timing of each heater in the next cycle.

That is, for the heater which is determined to have the maximum temperature difference between the set temperature and the detected temperature according to the result of the calculation executed by the determination command unit (CPU) 10, the longest in the next cycle. The first energization time is assigned, and conversely, the first energization is performed, and conversely, the heater that is determined to have the smallest temperature difference is assigned the shortest energization time and is energized last. Then, to the heater having the intermediate temperature difference, the intermediate energization time is assigned as the energization time of the next cycle.

A specific example of the procedure for determining the energization time in the determination command unit (CPU) 10 will be described below. For example, the set temperatures of the platen 69, the reheating platen 75, and the ink storage tank 81, which are the members to be heated in FIG.
When the temperatures are 125 ° C, 65 ° C, and 100 ° C, respectively, the detected temperatures after the first energization are 35 ° C, 30 ° C, and 2 ° C, respectively.
If it is 8 ° C, the temperature difference between them is 90 ° C, 3
Since the temperature is 5 ° C. and 72 ° C., the energization time to each heated member in the next cycle is determined to be, for example, 3 seconds (S14), 1 second (S16), and 2 seconds (S15), respectively. These energizations correspond to the period T2 in FIG. Thereafter, the same processing as described above is repeated until the detected temperature of each heated member matches the desired set temperature. This energization corresponds to the period after T3 in FIG.

In the example shown in FIG. 4, in the period Tk, the temperature difference between the set temperature and the detected temperature of the member to be heated is the maximum in the reheating platen 75 as shown in FIG.
The longest energization time is assigned to the heater 76, and energization is performed first. Next, the heater 6 corresponding to the platen 69
8 is assigned the second longest energization time, and finally the heater 83 corresponding to the ink storage tank 81 is assigned the minimum energization time. After each detected temperature matches the set temperature (YES in S17), normal ON / OFF
Temperature control is performed (S18). That is, as described above, the temperatures of the platen 69, the reheating platen 75, and the ink storage tank 81, which are the members to be heated, are sequentially determined by the temperature detection thermistors 21, 22, and 23 attached to the determination command unit ( Output to the CPU 10) and the judgment command section (C
The PU) 10 compares the set temperature with the detected temperature, and if the detected temperature of any heated member is low, outputs an energization command to the power control unit of the corresponding heater. The energization time to each heater is, for example, 100 msec. If, as a result of detecting the temperature, the temperature is not lower than the set temperature, the temperature of the next member to be heated is detected without issuing an energization command, After that, this process is sequentially repeated.

An example of another temperature control is shown in the flowchart of FIG. First, when the power is turned on and the printer is started (S2), each heater is energized for a fixed time Ts seconds (for example, 10 seconds) (S21), and the temperature detection thermistor for the corresponding heated member outputs the data. The temperature rise is calculated and calculated based on the signal and stored (S22). If the detected temperature at this time is T1, the room temperature is Troom, and the set temperature of the corresponding heated member is Tgoal, the temperature difference Δt1 between the heater and the room temperature is Δt1.
Is Δt1 = T1−Troom, and the difference Δtg1 between the set temperature and the detected temperature is Δtg1 = Tgoal−T1.

Further, the heater is turned on for Ts seconds (S
23) After that, the signal from the temperature detecting thermistor causes S2
The same calculation as in the case of 2 is performed to detect the detected temperature T of the heated member.
2 is obtained, and the temperature difference Δt2 between the heater and room temperature is
The difference Δtg2 between the set temperature and the detected temperature is calculated by the following equation (S24). Δt2 = T2-Troom Δtg2 = Tgoal-T2 Next, when the detected temperature T2 is equal to or higher than the set temperature Tgoal (S25), the on / off control similar to S18 in FIG. 3 is performed (S26).

On the other hand, when the detected temperature T2 is equal to or lower than the set temperature Tgoal, the ratio between Δt2 and Δtg2 described above is further calculated, and it is checked whether this value is 1 or more (S27), 1 or more. If so, the energization time to the corresponding heater in the next cycle is set to, for example, half the previous energization time Ts (S29), and conversely Δt2 and Δt2.
If the ratio to tg2 is not 1 or more, the energization time to the next heater is set to, for example, 3/2 of the previous Ts (S2).
28) and returns to S23. Similarly, from S23 to S
The heater is controlled by repeating the procedure up to 29.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in S11 of the flowchart shown in FIG. 3, the energization time at the start of energization is uniformly set to 3 seconds, but the temperature detection thermistor may not be able to detect the rising temperature depending on the heat capacity of the heated member. In such a case, immediately after starting the operation of the equipment, lengthen the energization time to each heater,
For example, it may be 10 seconds. Further, it may be repeated until the difference in the rising temperature as the difference in the thermal characteristic of each thermal module can be detected. Further, in FIG. 4, the time width of the temperature control periods T2, T3, T4, ..., Tk, Tk + 1 is constant, but as the temperature of each heated member rises and the temperature difference from the set temperature decreases, By reducing the time width of this temperature control period, more accurate and efficient temperature control can be realized.

Further, the present invention is not effective only when the resistance value of the heating element changes with time, and is also effective in the initial stage of mounting the heating element. For example, in a device in which multiple types of heating element modules with different heat capacities can be installed as options, when it is up to the user to select which type of heating element module to install Moreover, there are cases where these modules have various heat capacities, and there is a case where it is not determined in advance which module is to be connected and used. By implementing the heater control device of the present invention immediately after starting, it becomes possible to perform appropriate heating control for each thermal module without knowing which thermal module is connected.

[0030]

As described above, according to the present invention, in a device such as a printer having a plurality of heaters, a change with time of each heating element of the plurality of heaters is detected, and a set temperature and a detected temperature suitable for each heating element are detected. Since the time and the timing of energizing the heating element are determined based on the temperature difference with the temperature difference, even if the resistance value of the heating element decreases with time,
There is no need to anticipate an increasing current value and to equip an excessive power supply unit, and it is always appropriate for multiple thermal modules that have different temperature settings, without considering the change in heating element resistance value over time. It is possible to control to the set temperature by increasing the temperature. It is also possible to shorten the waiting time of the user until the device becomes usable when the device is activated.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of a printer according to an embodiment of the present invention.

FIG. 2 is a block diagram of a heater control device according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a temperature control procedure.

FIG. 4 is a diagram showing an output timing of a control command signal to the power control unit.

FIG. 5 is a diagram showing how the temperature of each heated member rises.

FIG. 6 is a flowchart showing a temperature control procedure.

[Explanation of symbols]

 1 Printer Cross Section 10 Judgment Command Unit (CPU) 21 Temperature Detection Thermistor 22 Temperature Detection Thermistor 23 Temperature Detection Thermistor 41 Power Control Unit 42 Power Control Unit 43 Power Control Unit 68 Resistance Heating Element 69 Platen 72 Reheating Processing Unit 75 Reheating platen 76 Resistance heating element 80 Ink storage tank

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Claims (1)

[Claims] 1. A heated member heated by a heating element,
A plurality of thermal modules having temperature detection means for detecting the temperature of the member to be heated and a power control section for controlling power supply to the heating element, and the power control section based on signals from the temperature detection means. And a determination command unit for instructing the power supply time to each heating element, and the determination command section energizes each heating element for a predetermined time at the start of energization, and then each heating element based on the temperature rise value detected by each temperature detection unit. A heater control device in a printer or the like, which has means for determining a power supply timing to the heater.