JPH08286862A - Printer and power supply control method for printer - Google Patents

Abstract

PURPOSE: To allow a printer to manage power supply to a print resource by itself independently of a command of a host device. CONSTITUTION: When a timer finishes time-count of a prescribed time, a control circuit section 306 identifies a potential of an initializing signal monitored by a signal monitor section 302 is a potential for initialization or a potential caused by interruption of power by a host device to interrupt power supply from a power supply section 307 to a print processing section or part of the print processing section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a printer device that self-diagnoses an off state from a state of an interface signal and automatically controls a power supply state to a printing resource, and a power supply control method of the printer device.

[0002]

2. Description of the Related Art Conventionally, a printing apparatus, which is connected to a higher-level device via an interface cable and automatically turns on / off the power, has been turned off after a predetermined time has elapsed since the communication with the higher-level device was interrupted. When the power was turned on, the restart of data transmission from the host device was detected, and accordingly the power was turned on and printing was restarted.

[0003]

However, in the above-mentioned conventional example, since the power supplies are different on both sides of the interface cable, if only one of them (upper device or printing device) is turned on / off, the interface is changed. In some cases, the signal of the unit becomes unstable and becomes stable at the intermediate level of the logic level. At this time, there is a problem that the device side connected to the interface unit in the power-on state causes a malfunction. .

The present invention has been made to solve the above problems. In the first to fifth aspects of the present invention, electric power is individually supplied to the interface ports of the host device side and the printer device side. To control the power supply to the printing resource by making a self-judgment of the state of the interface by changing the potential level of the signal line on the interface by supplying the
It is an object of the present invention to provide a printer device capable of self-controlling the power supply to a printing resource and a power supply control method for the printer device.

[0005]

According to a first aspect of the present invention, there is provided an interface means for communicating with a host device, a print processing unit for processing and printing output information received from the host device, and Control means for controlling the print processing unit; power supply means for constantly supplying power to the control means; monitor means for monitoring the potential of a predetermined initialization signal output from the host device to the control means; When the potential of the initialization signal monitored by the monitor means is recognized as an initialization potential, a timer means for counting a predetermined time is provided,
When the control means has finished counting the predetermined time by the timer means, the potential state of the initialization signal monitored by the monitor means is the potential state for initialization, or the power supply of the host device is turned off. The power supply from the power supply unit to the print processing unit or a part of the print processing unit is cut off by discriminating whether it is in a potential state.

According to a second aspect of the present invention, the potential state of the initialization signal monitored by the monitor means is maintained while the power supply from the power supply means to the print processing section or a part thereof is cut off. And a control unit for determining whether the potential state of the initialization signal has transitioned to the potential state for initialization. In addition, the power supply from the power supply unit to the print processing unit or a part thereof is restarted.

According to a third aspect of the present invention, the monitor means controls ON / OFF of a power source applied to a resistor for pulling up a predetermined initialization signal output from the host device to the control means. To monitor the potential state of the initialization signal.

According to a fourth aspect of the present invention, the monitor means is an on / off means for turning on / off a power supply applied to a resistor for pulling up each interface line input of the interface means, and an initial stage of the interface line input. And a detection means for detecting the analog voltage value of the converted signal.

According to a fifth aspect of the present invention, interface means for communicating with a host device, control means for controlling a print processing unit for processing and printing output information received from the host device, and the control A power supply control method for a printer device, comprising:
A first detection step of detecting the potential level of the reset request line of the interface means, a first determination step of determining whether the detected potential level is within a first potential range, and a first step of using a timer. A first timing step of timing the time, and a first power-off for turning off power to the pull-up resistor connected to the interface means when the potential level is determined to be within the first potential range. And a second timing step of timing a second time by a timer, and a second step of determining whether the potential level of the reset request line of the interface means is within the second potential range.
And a second power-off step of shutting off the power supply from the power supply unit to the print processing unit when the potential level is determined to be within the second potential range. .

[0010]

In the first aspect of the present invention, the potential state of the initialization signal monitored by the monitor means is the potential state for initialization when the control means has finished counting the predetermined time by the timer means. Alternatively, the power supply from the power supply unit to the print processing unit or a part thereof is cut off by identifying whether the potential state is due to power-off of the host device,
This makes it possible for the printing apparatus to self-manage the power supply state for the printing resources without receiving an instruction from the higher-level apparatus, without depending on the instruction from the higher-level apparatus.

In the second aspect of the present invention, the control means controls the print processing unit or a part thereof when the determining means determines that the potential state of the initialization signal has changed to the potential state for initialization. The power supply from the power supply unit is restarted, and the control unit can detect the power-on state of the higher-level device and shift the print processing unit to the printable state.

In the third invention, the monitor means performs on / off control of a power supply applied to a resistor for pulling up a predetermined initialization signal output from the host device to the control means for initialization. Monitor the potential state of the signal,
It is possible to quickly and at a suitable timing discriminate whether the potential state of the initialization signal is the potential state for initialization or the potential state due to the power-off of the host device.

In a fourth aspect of the present invention, the detecting means outputs the initialization signal of the interface line input with the power supply applied to the resistor for pulling up each interface line input of the interface means by the on / off means. It is possible to detect the analog voltage value and monitor whether the potential state of the initialization signal is the potential state for initialization or the potential state due to the power-off of the host device.

In a fifth aspect of the invention, the potential level of the reset request line of the interface means is detected, and it is determined whether the detected potential level is within the first potential range at the time when the first time measurement is completed. However, when the potential level is determined to be within the first potential range, the potential level of the reset request line of the interface unit is set to the level while the power supply to the pull-up resistor connected to the interface unit is turned off. If the potential level is detected and the potential level is determined to be within the second potential range at the end of the second time counting, the power supply from the power supply unit to the print processing unit is shut off, and the initialization signal is output. The potential state of is a potential state for initialization, or a potential state due to the power-off of the host device, is quickly and at an appropriate timing identified,
It is possible for the printing apparatus side to self-manage the power supply state to the printing resource without an instruction from the host apparatus.

[0015]

【Example】

[First Embodiment] FIG. 1 is a block diagram for explaining the arrangement of a printer apparatus according to the first embodiment of the present invention.

In FIG. 1, reference numeral 301 denotes a host device which sends print information (character code, control code or print information conforming to a page description language) to the printer device P and receives status information from the printer device P. , Send print information.

The 302 signal monitoring section monitors the input of the reset signal 309, the data signal 310, and the strobe signal 312 from the host device 301, and outputs an error signal 311 to the host device 301.

Reference numeral 303 denotes a reception buffer unit, which is the upper device 30.
The print information input from 1 is stored. A data processing unit 304 analyzes print information and develops it into a print image. A printing unit (printer engine) 305 prints on a recording medium according to the bit image data output from the data processing unit 304, and includes, for example, a laser beam printer engine and an inkjet printer engine.

A control circuit unit 306 is a signal monitoring unit 302.
The ON / OFF of the switch SW2 is controlled based on the input from. The control circuit unit 306 is turned on / off by turning on / off the switch SW2.
Print processing units (reception buffer unit 303, processing unit 30)
4, the power supply from the power supply unit 307 to the printing unit 305) is cut off. Reference numeral 308 is a power supply line controlled by the control circuit unit 306. Reference numeral 313 is an AC power supply line, and 314 is a power supply line from the power supply unit that is constantly supplied.

FIG. 2 is a circuit block diagram for explaining an interface mechanism between the higher-level device shown in FIG. 1 and the printer device P.

In the figure, 101 is a data line for inputting data sent from the computer side control circuit 108 via the open collector inverter OC to the printer side signal monitoring section and control circuit section 106 via the TTL inverter IV.

The data input to the printer-side signal monitoring unit and control circuit unit 106 is sent to the printer-side signal monitoring unit 302 and control circuit unit 306.

Reference numeral 102 is a strobe for writing a signal, 103 is an error line, 104 is a reset line,
Reference numeral 105 is a monitoring line for the power supply on the printer side.

107 is an interface cable, and 109
Is an analog voltage input port, which indicates whether the initialization signal input via the reset line 104 is in a state for initialization or a state based on the cause of power-off on the host device 301 side and the potential state level and its progress. The control circuit unit 306 makes a determination based on the time and controls the on / off state of the switch SW1, and at the same time, the reception buffer unit 303 and the processing unit 30.
4. Control the power supply state to the printing unit 305. 110
Is a control line for the pull-up resistor power supply on the printer side.

In the figure, R1 to R5 are pull-up resistors on the printer side, R6 to R9 are pull-up resistors on the computer side, R10 is a pull-down resistor, OC is an open collector inverter, and IV is an inverter.

Correspondence between the present embodiment and each means of the first to fourth inventions and their functions will be described below with reference to FIGS.

The first aspect of the present invention is an interface means (interface cable 10) for communicating with the host device 301.
7) and a print processing unit (reception buffer unit 303, processing unit 3) that processes and prints the output information received from the host device.
04, the printing unit 305), a control unit (control circuit unit 306) for controlling the print processing unit, a power supply unit (power supply unit 307) for constantly supplying power to the control unit, and the control unit from the host device. To monitor the potential of a predetermined initialization signal output to the printer (the signal monitoring unit on the printer side and the control circuit unit 106), and the potential of the initialization signal monitored by the monitoring unit is recognized as the initialization potential. In this case, a timer means (timer in the printer-side signal monitoring unit and the control circuit unit 106) for counting a predetermined time is provided, and when the control circuit unit 306 has finished counting the predetermined time by the timer, the printer side Signal monitoring unit and control circuit unit 10
From the power supply unit 307 for the print processing unit or a part thereof, it is discriminated whether the potential state of the initialization signal monitored by 6 is a potential state for initialization or a potential state due to power-off of the host device. Thus, the printing apparatus side can self-manage the power supply state for the printing resource without the instruction from the higher-level device 301, by cutting off the power supply of the higher-level device 301.

According to a second aspect of the invention, the potential state of the initialization signal monitored by the monitor means is initialized while the power supply from the power supply means to the print processing section or a part thereof is cut off. Determination means (depending on the function of the signal monitoring unit 302) for determining whether or not the potential state of the initialization signal is the potential for initialization. When it is determined that the state has transited to the state, the control unit restarts the power supply from the power supply unit 307 to the print processing unit or a part of the print processing unit and the control unit does not send any command. It is possible to shift the print processing unit to a printable state by capturing the power-on state of.

According to a third aspect of the invention, the monitor means performs on / off control of a power source applied to a resistor R1 for pulling up a predetermined initialization signal output from the host device to the control means for initialization. A potential state of a signal is monitored, and the potential state of an initialization signal is identified quickly or at an appropriate timing whether it is a potential state for initialization or a potential state due to power-off of the host device 301. Is possible.

According to a fourth aspect of the invention, the monitor means includes an on / off means (switch SW1) for turning on / off the power applied to the resistor R1 for pulling up each interface line input of the interface means, and the interface line input. A detection unit (signal monitoring unit and control circuit unit 106) for detecting the analog voltage value of the initialization signal, and whether the potential state of the initialization signal is in the potential state for initialization, or The power supply control operation of the printer device according to the present invention will be described below with reference to the flowchart shown in FIG. 3, which makes it possible to monitor whether or not the power supply is in a potential state.

FIG. 3 is a flow chart showing a first embodiment of a power supply control method for a printer device according to the present invention. Note that (1) to (7) indicate each step.

First, when AC power is supplied to the power supply unit,
Initialization is performed after the power is turned on in the control circuit unit 306 (1). Then, the pull-up resistor R1 shown in FIG.
In order to turn off the power supplies of R5 to R5, the pull-up resistor power supply control line 110 shown in FIG. 2 is controlled (2). Then
100mse to stabilize the interface signal voltage
c Wait (3).

Next, the signal monitoring section 302 on the printer side reads the analog voltage input port 109, judges whether the read value is within the range of 3.5v to 5v for all three times (4), and if it is NO. For example, go back to step (3) and do Y
If it is ES, move to step (5), and use resistors R1 to R
Pull-up power supply control line 1 to turn on power supply
Control 10 Further, the control circuit unit 306 turns on the power line 308 to control the printer device P in a printable state.

Next, the print data from the host device 301 is put into a ready state for reception (6), and when the data is received, the print processing is performed ((7)).

During the processing of steps (6) and (7), the internal timer of the control circuit unit 306 interrupts every one second, and the flow chart of FIG. 4 described later is entered.

FIG. 4 is a flowchart showing a second embodiment of the power supply control method for the printer device according to the present invention. Note that (1) to (9) indicate each step.

When an entry is made to the processing by an interrupt during the processing of FIG. 3, first, the analog voltage input port 1
09 was read three times, and a value between 3.5v and 0v (a Low state when the host device was powered off or a reset signal (Low active) was sent from the host device) was read all three times. Check whether or not (1), and if NO, return and resume data reception and printing.

On the other hand, if the result of the determination in step (1) is YES, then it waits for 3 seconds to determine whether or not it is a reset signal from the host device 301 (2).

The value of the analog power supply input port 109 is read three times, and it is checked whether a value between 3.5v and 0v has been read all three times (3). If NO, the steps shown in FIG. Transition to (1).

On the other hand, if the result of the determination in step (3) is YES, that is, it is estimated that the upper device side is in the power-off state and the resistors R1 to R5 are powered off. Control (4).
Then, in order to stabilize the voltage at the interface part, 5
Wait for 00 msec (5), read the analog voltage input port 109 three times, and judge whether the value is 0-1.0v for all three times (6). If NO, error LED
(Not shown) is turned on, and the control circuit unit 306 stops (9).

On the other hand, if the result of the determination in step (6) is YES, that is, it is determined that the upper device side is completely in the power-off state, and the control circuit 306 turns off the power supply line 308 (7). Then, the analog voltage input port 109
Value is read three times, all three times wait until a value between 3.5v and 5v is read (8), and when read, the process proceeds to step (1) of the flowchart shown in FIG. .

Incidentally, the potential of the reset line 104 shows a voltage value close to 5 V when both the resistors R6 and R1 are applied with 5 V, and the power supply of the host device is turned off and the potential of the resistor R6 is reduced. If the power supply side is equivalent to GND and 5V is applied to the resistor R1, the reset line 10
4 is GND (5V power supply on the host side) and printer 5V
Since the resistor R1 and the resistor R6 are connected in series between the power supplies, the voltage value divided by the resistor R1 and the resistor R6 is shown, and the power supply of the host device is turned off to turn on the resistor R6. When the power supply side is equivalent to GND and the pull-up resistor power supply control line 110 is OFF, the reset line 104 shows a voltage value near the state (0V) connected to GND.

Correspondence between the present embodiment and each step of the fifth invention and its action will be described below with reference to FIG.

A fifth aspect of the present invention is an interface means (interface cable 107) for communicating with a host device.
And a control unit (control circuit unit 30) for controlling the print processing unit that processes and prints the output information received from the host device.
6) and a power supply unit (power supply unit 307) that constantly supplies power to the control unit, the first detection step of detecting the potential level of the reset request line of the interface unit in the power supply control method of the printer. 4 (step (1)), a first determination step (step (3) in FIG. 4) of determining whether the detected potential level is within a first potential range, and a timer for a first time period. And a power source for the pull-up resistor connected to the interface means when the potential level is determined to be within the first potential range. The first power-off step (step (4) in FIG. 4) of turning off the power and the second time of measuring the second time by the timer.
Timing step (step (5) in FIG. 4) and a second determination step (step (6) in FIG. 4) for determining whether the potential level of the reset request line of the interface means is within the second potential range. And a second power-off step of cutting off the power supply from the power supply unit to the print processing unit when it is determined that the potential level is within the second potential range (step (7) in FIG. 4). By executing the following, the potential state of the initialization signal is promptly identified at an appropriate timing whether the potential state for initialization is the potential state for initialization or the potential state due to the power-off of the host device, and the power to the printing resource is It is possible for the printing apparatus side to self-manage the supply state without an instruction from the host apparatus. [Second Embodiment] FIG. 5 is a circuit block diagram for explaining the interface configuration of a printer apparatus according to the second embodiment of the present invention. The same components as those in FIG. 2 are designated by the same reference numerals.

The difference from FIG. 2 is that the analog voltage input port 109 is not provided.

Hereinafter, power supply control in the printer device having such a configuration will be described with reference to FIGS. 6 and 7.

FIG. 6 is a flow chart showing a third embodiment of the power supply control method for a printer according to the present invention. In addition,
(1) to (7) show each step.

First, when AC power is supplied to the power supply unit,
Initialization is performed after the power is turned on in the control circuit unit 306 (1), and the pull-up resistor power control line 110 is controlled to turn off the resistors R1 to R5 shown in FIG. 5 (2). . Next, wait for 100 msec so that the voltage of the interface signal becomes stable (3).

Next, the printer-side signal monitoring unit checks whether the reset signal is "H" (5). If NO, the process proceeds to step (4) of the flowchart shown in FIG. 7 to be described later, and if YES, Then, the process goes to step (5) to control the pull-up resistor power supply control line 110 to turn on the power supplies of the resistors R1 to R5. Further, the control circuit unit 306 turns on the power supply line 308 to control the printer device P in a printable state.

Next, the printer waits in a state of being able to receive the print data from the host device 301 (6), and when the data is received, the print processing is performed until there is no more data (7).
During the processing of steps (6) and (7), the internal timer of the control circuit unit 306 interrupts every one second, and the process of the flowchart shown in FIG. 7 is entered.

FIG. 7 is a flow chart showing a fourth embodiment of the power supply control method for the printer device according to the present invention. In addition,
(1) to (6) show each step.

When an interrupt occurs according to the procedure shown in the flow chart shown in FIG. 6, the flow chart shown in FIG. 7 is entered, and it is first judged whether print data has not come for 1 minute (1). If it returns and the result is YES, the process proceeds to step (2) and the resistor R
In order to turn off the power supplies 1 to R5, the pull-up resistor power supply control line 110 is controlled.

Next, wait for 500 msec to stabilize the voltage at the interface portion (3), judge whether the reset signal is "L" (4), and if NO, step (5) shown in FIG. ), And if YES, the control circuit unit 306 turns off the voltage of the power supply line 308 (5). Next, the signal monitoring unit 302 waits until the reset signal becomes "H" (6), and the reset signal becomes "H".
When it becomes, it changes to step (5) shown in FIG.

According to the above-mentioned embodiment, it has an interface with the host device 301, and an independent power source (the input / output port P is provided between the input / output ports P1, P2 of the interface means).
A printer having power supplied to the second side from a power supply unit 307 of the printer and having a potential level set to a predetermined intermediate potential by pull-up resistors R1 to R5 (during initialization) (FIGS. 1 and 2). 5), the printing device operating in accordance with a command via the interface with the higher-level device 301 monitors the initialization signal of the interface means for the printing device (signal monitoring unit 3).
02), means for constantly supplying power to the control device in the printing apparatus (power supply unit 307), and means for turning off the power supply of the printing circuit of the printing apparatus (switch SW).
The control means in the printing apparatus monitors the initialization signal, and determines whether the initialization signal is in a state for initialization or a state due to power-off of the information processing apparatus (illustrated). The internal power supply of the printing apparatus can be turned off by judging from the potential state before and after the elapse of time of the internal timer).

Further, while the power is off, the initialization signal monitor means (signal monitoring section 302) has means for detecting that the initialization signal is no longer in the initialization state, and the detection means ( If it is determined by the signal monitoring unit 302) that the initialization signal state is not set and that the information processing device is powered on, the control circuit unit 30
6 can turn on the power source and transit to a printable state.

The initialization signal monitoring means (signal monitoring section 302) is means for turning off the power supply of the pull-up resistors R6 to R10 of the input signal from the host device 301 of the interface circuit portion on the printing device side. (Not shown), and sends the initialization signal to the signal monitoring unit 30.
2 is a printing device for detecting as an analog voltage, and the analog voltage detecting means (at a constant power-on state during printing or receiving data for printing (the pull-up resistors R1 to R5 are in an ON state)) (Not shown), the voltage value of the initialization signal is read, and whether the initialization signal is being output or the host device is powered off is determined by the timer means (internal timer of the signal monitoring unit 302) and the read voltage value. It is determined and the printing apparatus is automatically changed to the power-off mode or the initialization processing.

Further, when the power-on mode is set, the power source of the pull-up resistor is turned off, the timer means waits for a certain period of time, and then the analog voltage value is read to detect the logic level of "H". The power of the pull-up resistor is turned on, the power of the circuit for printing is turned on, and a transition can be made to a printable state.

The other monitor means for the initialization signal detects the input signal from the host device 301 of the interface circuit portion on the side of the printing device by turning off the power supply of the pull-up resistors R1 to R5. This is realized during printing or while receiving print data (the circuit for printing is turned on, the pull-up resistor R1 is
~ R5 is also turned on), whether or not the print data is sent from the host device 301 via the interface means is periodically checked using the timer means, and if the print data is not sent for a certain time, the pull-up is performed. The power source of the resistors R1 to R5 is turned off by the switch SW, the timer means waits for a certain period of time, the initialization signal is read, and if it is judged as "H", the pull-up resistor R
The power supplies 1 to R5 are turned on by the switch SW, and a transition is made to a printable state.

On the other hand, when the initialization signal is read and judged to be "L", the power supply of the circuit for printing is turned off (power off mode).

In this way, it is possible to wait for the initialization signal to go to "H" in the above mode, and transition to the power-on sequence.

[0061]

As described above, the first aspect of the present invention
According to the invention, when the control means finishes measuring the predetermined time by the timer means, the potential state of the initialization signal monitored by the monitor means is the potential state for initialization, or the higher-order state. Since the power supply from the power supply unit to the print processing unit or a part thereof is cut off by identifying whether the potential state is due to the power-off of the apparatus, the power supply state to the printing resource can be determined regardless of the instruction from the host apparatus. Even if there is no instruction from the host device, the printing device side can manage itself.

According to the second aspect of the invention, the control means determines the print processing section or a part thereof when the determining means determines that the potential state of the initialization signal has changed to the potential state for initialization. Since the power supply from the power supply means is restarted, the control means can detect the power-on state of the higher-level device and shift the print processing unit to the printable state.

According to the third invention, the monitor means performs on / off control of a power supply applied to a resistor for pulling up a predetermined initialization signal output from the host device to the control means to initialize the power supply. Since the potential state of the initialization signal is monitored, it is possible to quickly and at an appropriate timing identify whether the potential state of the initialization signal is the potential state for initialization or the potential state due to the power-off of the host device. You can

According to the fourth aspect of the invention, the detecting means sets the interface line input initialization signal with the power applied to the resistor for pulling up each interface line input of the interface means by the on / off means. Since the analog voltage value is detected, it is possible to monitor whether the potential state of the initialization signal is the potential state for initialization or the potential state due to the power-off of the host device.

According to the fifth aspect of the invention, the potential level of the reset request line of the interface means is detected, and the detected potential level is the first level at the time when the first time measurement is completed.
If the potential level is determined to be within the first potential range, the interface means is connected to the pull-up resistor connected to the interface means while the power is off. The reset request line potential level is detected, and when the potential level is determined to be within the second potential range at the end of the second time counting, power is supplied from the power supply unit to the print processing unit. Is interrupted, the potential state of the initialization signal is identified as a potential state for initialization or a potential state when the power of the host device is turned off quickly and at an appropriate timing to supply power to the printing resource. Even if there is no instruction from the higher-level device, it is possible to realize a process in which the printing device manages itself.

Therefore, there is an effect that the printing device side can self-manage the power supply to the printing resource without depending on the command from the upper device side.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of a printer device according to a first embodiment of the present invention.

FIG. 2 is a circuit block diagram illustrating an interface mechanism between a higher-level device shown in FIG. 1 and a printer device.

FIG. 3 is a flowchart showing a first embodiment of a power supply control method for a printer device according to the present invention.

FIG. 4 is a flowchart showing a second embodiment of the power supply control method for the printer device according to the present invention.

FIG. 5 is a circuit block diagram illustrating an interface configuration of a printer device according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing a third embodiment of a power supply control method for a printer device according to the present invention.

FIG. 7 is a flowchart showing a fourth embodiment of a power supply control method for a printer device according to the present invention.

[Explanation of symbols]

 301 Host device 302 Signal monitoring unit 303 Reception buffer unit 304 Processing unit 305 Printing unit 306 Control circuit unit 307 Power supply unit

Claims (5)

[Claims] 1. An interface unit for communicating with a higher-level device, a print processing unit for processing and printing output information received from the higher-level device, a control unit for controlling the print processing unit, and the control unit. A power supply means for constantly supplying power, a monitor means for monitoring a potential of a predetermined initialization signal output from the host device to the control means, and a potential of the initialization signal monitored by the monitor means are initially set. A potential of the initialization signal monitored by the monitoring means when the control means terminates the counting of the predetermined time by the timer means when the predetermined potential is recognized. A power supply from the power supply unit for the print processing unit or a part of the print processing unit by identifying whether the state is a potential state for initialization or a potential state when the power supply of the host device is turned off. A printer device characterized by cutting off supply. 2. The potential state of the initialization signal monitored by the monitor means is changed to a potential state for initialization while the power supply from the power supply means to the print processing section or a part thereof is cut off. And a control unit for determining whether the potential state of the initialization signal has transitioned to the potential state for initialization. 2. The printer device according to claim 1, wherein power supply from the power supply unit to a part is restarted. 3. The monitor means controls ON / OFF of a power supply applied to a resistor for pulling up a predetermined initialization signal output from the host device to the control means to control the potential state of the initialization signal. The printing apparatus according to claim 1, which is monitored. 4. The monitor means detects an on / off means for turning on / off a power applied to a resistor for pulling up each interface line input of the interface means, and an analog voltage value of an initialization signal of the interface line input. The printing apparatus according to claim 1, further comprising: 5. An interface unit for communicating with a higher-level device, a control unit for controlling a print processing unit for processing and printing output information received from the higher-level device, and a power supply for constantly supplying power to the control unit. And a first detecting step of detecting a potential level of a reset request line of the interface means, and determining whether the detected potential level is within a first potential range. The first determination step and the first by the timer
And a first power supply for turning off the power supply to the pull-up resistor connected to the interface means when the potential level is determined to be within the first potential range. An off step, a second timing step of timing a second time by a timer, a second determination step of determining whether the potential level of the reset request line of the interface means is within a second potential range, and A second power-off step of cutting off the power supply from the power supply unit to the print processing unit when the potential level is determined to be within the second potential range. Control method.