JPH0263779A - Carriage motor drive device of printer device - Google Patents

Abstract

PURPOSE:To allow the generated torque of a carriage motor to change and thereby make possible the efficient drive of the motor by controlling the supply of electric current to the carriage motor depending upon the temperature condition of a printer. CONSTITUTION:A constant current circuit control section 7 determines the reference amount of electric current from the operating condition of a carriage motor which is obtained from CPU 9 and the temperature condition of a printer which is obtained from a temperature detection circuit 8. Then said control section controls an electric current supply to the carriage motor 4 through a constant current circuit 6 so that the amount of electric current applied to the carriage motor 4 does not exceed the reference amount of electric current. In this case, if the temperature of the printer is higher than a temperature detected by the temperature detection circuit 8, an output 10 from the temperature detection circuit 8 at 'H' level. Consequently, no change occurs in the reference amount of electric current and the amount of electric current supplied to the carriage motor 4 is normal. In the meantime, if the temperature of the printer is lower than the detected temperature, the output 10 from the temperature detection circuit 8 is at 'L' level. Therefore, the reference amount of electric current is low due to a normal temperature condition. Subsequently, it is possible to prevent damage caused to the carriage motor 4 due to heating at the time of normal or high temperatures. Thus the efficient drive of the motor is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a carriage motor drive device for a printer device suitable for driving a motor according to temperature conditions.

(Prior Art) Conventionally, a constant current circuit has been used as a carriage motor drive device in a printer device such as a serial printer. and generates a constant torque when stopped.

However, there is a problem in that the torque of the carriage motor required to drive the carriage depends on the environmental temperature during its operation. Generally, the lower the temperature, the greater the torque required. Therefore, in order to realize efficient motor drive, the value must be set large to match the minimum guaranteed operation temperature of the printer.

However, conventionally, it has not been possible to change the torque generated by the carriage motor depending on the temperature condition, so if the maximum torque is generated at low temperatures, excessive torque will occur at normal and high temperatures, and as a result, the carriage motor will heat up and be damaged. There was a drawback to it.

(Problem to be solved by the invention) As mentioned above, conventionally, when the structure was configured to efficiently drive the carriage motor by generating the maximum torque at low temperatures, excessive torque was generated at room temperature and high temperature, resulting in generation of heat. This had the disadvantage of causing damage to the carriage motor.

The present invention was made in view of the above points, and it is possible to change the torque generated by the carriage motor depending on the temperature condition,
It is an object of the present invention to provide a carriage motor drive device for a printer device that can drive a motor with high efficiency.

[Structure of the Invention] (Means for Solving the Problems) That is, the carriage motor drive device of the printer device according to the present invention is configured such that when the amount of current flowing through the carriage motor exceeds a reference current amount, the carriage motor is The current supply is controlled to stop, and when the printer temperature is lower than a preset detected temperature, the reference current amount is set to be larger than when the printer temperature is higher than the detected temperature.

(Function) According to the above configuration, when the printer temperature is lower than the detected temperature, the amount of current supplied to the carriage motor increases, thereby increasing the generated torque. Therefore, the torque generated by the carriage motor can be changed depending on the temperature state, and the motor can be driven efficiently.

(Embodiment) Hereinafter, a carriage motor drive device for a printer device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the circuit configuration thereof.

First, before explaining this circuit configuration, the configuration of the carriage mechanism section in the printer device will be explained with reference to FIG.

As shown in FIG. 6, the carriage mechanism of the printer device mainly includes a carriage rail 1, a carriage 2, a timing belt 3, a carriage motor 4, and a pulley 5. The carriage 2 is slidably supported by the carriage rail 1 and moves on the carriage rail 1 by driving a carriage motor 4. The carriage motor 4 is composed of, for example, a four-phase stepping motor, and is driven by a carriage motor drive device shown in FIG.

Next, the circuit r of the carriage motor drive device shown in FIG.
The f4 configuration will be explained.

This carriage motor drive device includes excitation coils 311ia and 36b (actually, as shown in FIG.
a constant current circuit 6 that supplies current to the constant current circuit 6 (for convenience of explanation, only two are shown), a constant current circuit control section 7 that controls the current supply of the constant current circuit 6, and a temperature detector that detects the printer temperature. Circuit 8, motor driven! It consists of a CPU 9 that notifies the constant current circuit control section 7 of t3 (acceleration/deceleration, low speed, stop).

To be more specific, the CPU 9 uses the address bus 12,
I10 through data bus 13 and control bus 14
Information indicating the operating state of the carriage motor 4 is sent to the port 15. That is, the CPU 9 uses the control bus 14
Output two pieces of information: one to access the I10 port and one to write data to the I10 port,
It is sent to each of 110 ports (not shown). Next, the CPU 9 outputs an I10 port address to the address bus 12 to designate a specific 110 port, that is, the I10 port 15.

Next, the CPU 9 loads information indicating the operating state of the carriage motor 4 onto the data bus 13 and sends the information to the I10 port 15.
send to In this case, the information is expressed as follows using, for example, the lower two bits of the data.

Lower 2 bits: Meaning 11: Acceleration/deceleration 10: Low speed 01: Stop 00; Carriage free Next, the I10 port 15 in the constant current circuit control section 7 will be explained.

The I10 port 15 is composed of two parts: a register section and a decoder section. The register section receives data sent from the CPU 9 and latches it until the next data arrives. The decoder section decodes the output of the register section,
Depending on the result, the two outputs 1B of 110 port 15,
The level state (rHJorrLJ) of No. 17 is determined as follows.

Output 16 Output 17: Carriage status rHJ
rHJ: Acceleration/deceleration rHJ rLj: Low speed rLJ rHJ: Stop rLJ rLJ: Carriage free Next, the temperature detection circuit 8 will be explained.

Temperature detection by this temperature detection circuit 8 is performed by a thermistor 25.
carried out by. The temperature characteristic of the resistance value of the thermistor 25 is such that the value decreases as the temperature increases. This thermistor 25 constitutes a voltage dividing circuit together with the resistor 2G, and the output of this voltage dividing circuit is connected to one terminal of the comparator 27, and the output of the voltage dividing circuit 28 is connected to a child terminal of the comparator 27. It is used as the reference voltage.

To explain its operation, the comparator 27 converts the output voltage of the voltage dividing circuit on the thermistor 25 side into the comparator 27.
It is compared with the reference voltage on the child terminal side of No.7.

Here, the output voltage of the comparator 27 on the thermistor 25 side is influenced by the temperature characteristics of the thermistor 25 described above. That is, as the temperature increases, the resistance value of the thermistor 25 decreases, and the voltage on the thermistor 25 side of the voltage dividing circuit (output voltage of the voltage dividing circuit) decreases. As a result,
By comparison with the reference voltage on the child terminal side of the comparator 27, if the temperature is higher than a certain temperature that is higher than the voltage at one terminal of the comparator 27, the output 10 of the comparator 27 becomes rHJ level. On the other hand, if the temperature is below a certain level, the output 10 of the comparator 27 will be at the rLJ level. Here, the reference voltage at the child terminal of the comparator 27 described above indicates the temperature detected by the temperature detection circuit 8. FIG. 2 shows the relationship between this detected temperature and the output 10 of the comparator 27.

Next, the constant current circuit 6 will be explained.

The flip-flop 29 serves to control on/off of the transistor 34 using two inputs 32 and 33. The 33 side is connected to the output of the oscillator (O3C) 30, and is valid during the rLJ level period of the oscillation waveform (square wave). On the other hand, the side 32 is connected to the output of the comparator 24, and is valid during the period when the output is at the rLJ level. The inputs 33, 32 and output Q (valid at rHJ level) of this flip-flop 29 are as follows.

Input 33 Human power 32: Output Q rLJ rLJ : rHJ rLJ rHJ : rHJ "H""L" = "L" rHJ rH,J : rLJ In this way, the rHJ level signal is output from the flip-flop 29 according to output 33.32. When the signal is output, the transistor 34 is turned on. This transistor 34 is a switching transistor, and is connected to one end of a set of excitation coils 36a, 36b constituting the carriage motor 4, and supplies current to the excitation coils 36a, 36b when turned on. On the other hand, the transistors 35a and 35b are transistors for controlling the phase of the carriage motor 4, and are connected to the other ends of the excitation coils 36a and 36b, respectively. The current from the transistor 34 is applied to the excitation coils 3Ga, 3To according to
control whether or not to flow.

The resistor 23 is a resistor provided to detect the amount of current flowing through the carriage motor 4. When current flows through this resistor 23, an electromotive force is generated across the resistor 23, and the value at that time becomes a measure of the amount of current. The electromotive force generated in the resistor 23 is inputted to one terminal of the comparator 24 after excess noise components are removed by a low-pass filter 31 .

Next, the comparator 24 in the constant current circuit control section 7 will be explained.

The comparator 24 is a comparator for controlling the current of each phase of the carriage motor 4.

The detected electric current mQ is the value of the electromotive force of the resistor 23 described above. In addition, the reference voltage that is the reference current amount for determining the current amount is connected to the resistors 18 to 20 and the I10 port 15.
and inverter 37, comparator 24
is input to the child terminal of In Fig. 2, this comparator 2
The input signal 11 on the child terminal side of No. 4 is shown.

To explain its operation, first, the set side of the flip-flop 29 is activated by the oscillator 30, and the output Q of the flip-flop 29 becomes rHJ level. As a result, the transistor 34 is turned on, and either the transistor 35a or the transistor 35b is turned on, so that a current flows through the carriage motor 4. As a result, an electromotive force is generated in the resistor 23. Then, the electromotive force (terminal voltage of the resistor 23) is compared with the reference voltage on the child terminal side in the comparator 24', and when it exceeds the reference voltage, the output of the comparator 24 becomes rLJ level.

As a result, the flip-flop 29 is reset, the output Q becomes rLJ level, and the transistor 34 is turned off. This state continues until the flip-flop 29 is set. FIG. 3 shows the relationship between this flip-flop 29 and the resistor 23.

Note that in the circuit shown in FIG. 1, one set of excitation coils of the carriage motor 4 is omitted for convenience of explanation.
Although one set of constant current circuit 6 and constant current circuit control section 7 is omitted, in reality, the configuration is as shown in FIG. 4 when carriage motor 4 is a four-phase stepping motor. Further, FIG. 6 shows the timing of the phase excitation signal at this time.

Next, the operation of this embodiment will be explained.

The constant current circuit control unit 7 operates according to the operating state (acceleration/deceleration, low speed, stop) of the gear ridge motor 4 obtained from the CPU 9 and the temperature state of the printer obtained from the temperature detection circuit 8.
The reference current amount (the reference voltage input to the child terminal of the comparator 24) is determined, and the amount of current flowing to the carriage motor 4 (the electromotive force of the resistor 23 input to one terminal of the comparator 24) exceeds this reference current amount. The current supply to the carriage motor 4 by the constant current circuit 6 is controlled to prevent this.

In this case, if the printer temperature is higher than the temperature detected by the temperature detection circuit 8 (for example, room temperature 25°C)? FjA
Since the output 10 of the degree detection circuit 8 is at the rHJ level, there is no change in the amount of reference current, and a normal current flows through the carriage motor 4.

On the other hand, when the printer temperature becomes lower than the detected temperature, the output IO of the temperature detection circuit 8 becomes the rLJ level, so that the reference current amount becomes lower than in the normal state. As a result, a larger current flows through the carriage motor 4 than at normal temperature, and the torque generated by the carriage motor 4 also increases.

In this way, a large current flows to the carriage motor 4 only when the printer temperature is low. Therefore, the torque generated by the carriage motor 4 can be changed at low temperatures, at room temperature, and at high temperatures, and by generating the maximum torque only at low temperatures, damage to the carriage motor 4 due to heat generation at room temperature and high temperatures can be avoided. This enables efficient motor drive.

[Effects of the Invention] As described above, according to the present invention, since the current supply to the carriage motor is controlled depending on the temperature state of the printer, the torque generated by the carriage motor is changed depending on the temperature state, and the motor can be driven efficiently. It is something that will come.

[Brief explanation of the drawing]

1 to 6 are diagrams for explaining one embodiment of the present invention, respectively. FIG. 1 is a block diagram showing the circuit configuration, and FIGS. 2 and 3 are diagrams for explaining the operation. Signal waveform diagram, Figure 4 is a block diagram showing the circuit configuration when the carriage motor is a 4-phase stepping motor, Figure 5 is a timing chart of the phase excitation signal of the 4-phase stepping motor, and Figure 6 is the printer device. FIG. 1... Carriage rail, 2... Carriage, 3...
...Timing belt, 4...Carriage motor, 5
...Pulley, 6... Constant current circuit, 7... Constant current circuit control section, 8... Temperature detection circuit, 9... CPU, 1
2...Address bus, 13...Data bus, 14.
...Control bus, 15...I10 port, 18
~23... Resistor, 24 and 27... Comparator, 25... Thermistor, 29... Flip-flop, 30... Oscillator (O5C), 31... Low pass filter, 34.35a and 36b. ... Transistor, 3[ia and 3[ib... Excitation coil, 37...
・Inverter.

Claims (1)

[Claims] Current supply means for supplying current to the carriage motor; current amount detection means for detecting the amount of current flowing through the carriage motor; and current supply means when the amount of current exceeds a reference current amount. current supply control means for controlling the stop of current supply by the printer; temperature detection means for detecting the printer temperature; 1. A carriage motor drive device for a printer apparatus, comprising: a reference current amount setting means for setting a reference current amount larger when the current amount is higher than the current amount.