JPS6294373A - Printer - Google Patents

Abstract

PURPOSE:To alleviate a burden to be applied on the operator and contrive a smaller power consumption and a longer useful life, by connecting a power switch between output terminals of an external power source through a driving coil of a first relay, and connecting a contact of a second relay between both terminals of the power switch. CONSTITUTION:With a power switch 16 depressed, a driving coil 13b of a first relay is energized by an external power source, and contacts 13a of the first relay are closed to supply electric power from the external power source to a power source circuit 14. A driving current is supplied from the power source circuit to a driving coil 7b of a second relay, whereby a contact 17a of the second relay connected between both terminals of the switch 16 is closed. As a result, when the lapse of time to the inputting of the next printing data exceeds a predetermined period of time, a circuit-breaking command is outputted to a switching circuit 18, whereby the switching circuit is opened. Then, the supply of current to the driving coil 17b of the second relay is cut off, and the contacts 13a of the first relay are opened to cut off the supply of power from the external power source to the power source circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing device that has a power supply circuit within the device and prints out characters based on print data input from an external control device.

[Prior Art] Generally, a printing device incorporated in an information processing system receives print data such as character codes, line feed codes, page feed codes, etc. sent from a host computer as an external control device, and then stores the print data in a RAM or the like. The character codes stored in the reception buffer are stored in the reception buffer formed in the internal storage section, and the character codes stored in this reception buffer are sequentially read out, and the printed characters of the printing wheel or the dot pattern of the character generator corresponding to the read character codes are read out from the ROM etc. and the carriage is moved. The printer is configured to use a print head mounted on the printer to print out corresponding characters on a print sheet set on a platen.

In such a printing device, there is a drive 7Ii11 that drives each f.Ii motor such as a printing wheel motor, paper feed motor, carriage motor, etc. built into the device, and a CPU.
, a power supply circuit for supplying control voltage for operating RAM, etc. is incorporated into the same device.

A power supply circuit built into such a printing device is configured as shown in FIG. 3, for example. 1 in the figure is an AC connected to a commercial power source (not shown) as an external power source.
1 input through this AC plug 1.
The 00V AC voltage is supplied to the power supply circuit 4 via the fuse 2 and the power switch 3. The 100V AC voltage input into the power supply circuit 4 is filtered by a noise filter 5 to remove ringtones, reduced to a desired voltage by a power transformer 6, and then rectified by a diode bridge and a smoothing capacitor, etc. The circuit 7 converts the voltage into a DC drive voltage and control voltage. The drive voltage and control voltage output from the power supply circuit 4 are supplied to each component 8 such as the aforementioned various motors, CPU, and RAM.

In a printing device having such a power supply circuit, when printing out data obtained by an information processing system, first turn on the power switch 3 to make it ready to receive print data, and then print from the host computer 9. Let them enter data. When a series of print output processing for the print data sent from the host computer 9 is completed, the power switch 3 is shut off.

[Problems to be Solved by the Invention] However, as described above, the printing device incorporating a power supply circuit within itself has the following problems. That is, it is natural that the operator needs to turn on the power switch 3 in order to operate this printing device.
The operator must always turn off the power switch 3 even after a series of printout operations are completed. Normally, it takes a long time to print out the huge amount of data obtained by an information processing system, so the operator performs the initial printing start operation including turning on the power 17 The printing operation starts normally. After confirming that something has happened, they often leave the area. In such a case, the power switch 3 of the printing device continues to be turned on even after the printing operation is completed. Therefore, there is a risk that the operator may forget to turn off the power switch 3. This requires unnecessary power consumption, and there is a concern that the lifespan of the entire device may be shortened.

The present invention was made based on the above circumstances, and its purpose is to automatically print data when the next print data is not input within a predetermined time from the time of print output using a relay. By cutting off the power to the device itself,
It is an object of the present invention to provide a printing device that can reduce the burden on the operator, reduce power consumption, and extend the lifespan.

[Means for Solving the Problems] The printing device of the present invention includes a first relay contact inserted between an external power source and a power supply circuit, and a first relay contact between the output terminals of the external power source.
A power-on switch is connected through the drive coil of the relay, a contact of a second relay is inserted between both terminals of this power-on switch, and the drive coil of the second relay is driven from the same power supply circuit. A switching circuit is inserted in the current supply path. The timer unit, which measures the elapsed time from when characters are printed, sends a circuit cutoff command to the switching circuit when a predetermined time has elapsed before the next print data is input. It is.

[Operation] In the printing device configured as described above, when the power switch is pressed, the drive coil of the first relay is energized by the external power supply, the contacts of this first relay are opened, and the power supply circuit is connected to the external power supply. Power is supplied. Then, a drive current is supplied from the power supply circuit to the drive coil of the second relay, and the contacts of the second relay inserted between both terminals of the power switch are closed. As a result, even if the power switch is released, the contacts of the first relay are not released and power continues to be supplied to the power supply circuit.

Additionally, if the elapsed time from the print output operation based on the input print data until the next print data is input exceeds a predetermined time, a circuit cutoff command is sent to the switching circuit, and the switching circuit is opened. Ru. Then, the current supply to the drive coil of the second relay is cut off, and the contacts of the second relay are opened. As a result, the current supply to the drive coil of the first relay is cut off, the contacts of the first relay are opened, and the power supply from the external power supply to the power supply circuit is cut off.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a printing device according to an embodiment. Reference numeral 11 in the figure is an AC plug connected to a commercial power source (not shown) as an external power source, and this AC plug 11
The 100cm AC voltage input from the power supply line 12a,
12b and is input to the power supply circuit 14 via the contact 13a of the first relay 13. A fuse 15 is inserted in the power line 12a that connects the AC plug 11 and the contact 13a of the first relay 13, and the power line 12a;
A push-button power-on switch 16 is connected between the terminals 12b and 12b via the drive coil 13b of the first relay 13. Furthermore, a contact 17a of a second relay 17 is inserted between both terminals of this power-on switch 16. One end of the drive coil 17b of the second relay 17 is connected to the npn switching transistor 18 of the power supply circuit 14.
It is grounded between the collector and the transmitter. Further, the base terminal of the switching transistor 18 is connected to the +5V output terminal of the power supply circuit 14 via a bias resistor 19. Furthermore, this base terminal is grounded via a push button type power cutoff switch 20.

The power supply circuit 14 is composed of, for example, the above-mentioned noise filter, power transformer, rectifier circuit, etc., and converts the 100cm AC voltage inputted through the contact 13a of the first relay 13 into the control voltage of 5V DC, for example. V. and DC 1
Drive type 1+ of 2 to 24 V: Convert to V, . and a control voltage V of 5v.

are supplied to the drive coil 17b of the second relay 17, and the CPU 21 . The signal is supplied to a storage section 22 and a timer circuit 23, which are configured with RAM, ROM, etc. In addition, the driving voltage VD of 12 to 24V is the printing wheel motor,
carriage motor.

The printing unit 24 is supplied with various motors such as a paper feed motor.

The CPU (Central Processing Unit) 21 executes various arithmetic processes, and also receives print data such as character codes, line feed codes, page feed codes, etc. from a host computer 26 as an external control device via a pass line 25.
Interface 27゜ Early storage section 22 for storing the reception buffer, character position of the print wheel corresponding to the character code, etc. A printing section 24 that prints out a character corresponding to the input character code based on the character position read from the storage section 22. Controls the output boat 28, etc. The output terminal of this output port 28 is connected to the base terminal of the switching transistor 18 via an open collector buffer 29.

In such a printing device, when printing out data processed by an information processing system, when the operator inserts the AC plug 11 into an external power outlet and presses the power on switch 16, the power lines 12a, 12b and the power supply are connected. A drive current is supplied from an external power supply to the drive coil 13a of the first relay 13 via the closing switch 16, and the first
The relay 13 is activated and the contact 13a is closed. In conclusion, in Song, 100V AC voltage from the external power supply was applied to the power supply circuit 14.
supplied to The power supply circuit 14 to which the 100V AC voltage is supplied converts this AC voltage into a +5V control voltage V and drive voltage V, which are then sent to the CPU 21, printing section 24. Storage part 2
2 and other components.

Further, when the power supply circuit 14 starts normal operation, an H level conduction voltage is applied to the base of the switching transistor 18 from the output terminal of the control voltage Vc of 5.1 through the bias resistor 19. On the other hand, the output terminal of the output port 28 is C
The open collector buffer 29 is in an off state because it maintains the L level unless a circuit cutoff command is input from the PU 21. Switching transistor 18
becomes conductive. When the switching transistor 18 becomes conductive, a drive current is supplied from the simple power supply circuit 14 to the drive coil 17b of the second relay 17. Then this second
The relay 17 is activated and the contact 17a is closed. When the contact 17a of the second relay 17 is opened, the drive current of the drive coil 13b of the first relay 13 is not cut off even if the push-button power switch 16 is released, so the contact 13a will never be released.

Therefore, this printing device N becomes operational.

Control voltage V output from the power supply circuit 14. When the drive voltage V reaches the iE standard voltage value, the CPU 21 executes print output processing according to the flowchart of FIG. That is, first the storage unit 22. Initial processing of the printing unit 24 and the like is executed. When the predetermined printing process is completed, the print data input from the host computer 26 to the I10 interface 27 is stored in the reception buffer of the storage unit 22 at Pl. Next, at P2, the contents of the receive buffer are
1. Check whether the person is in a state of ability. In other words, if the receive buffer is filled with character codes for one line, for example, or if the buffer becomes full, or if the I10 interface 2
If the print data read from 7 is a code such as a line feed code, page feed code, or print command code that requires the contents of the reception buffer to be immediately printed out, set the elapsed time T counted by the timer section 23 to 0. At the same time as resetting, start the timer in step 11■. Then, the content of the reception buffer is printed out by the printing unit 24. Note that if the contents of the reception buffer are not yet printable at P2, the process returns to P1 and the next print data from the I10 interface 27 is read and stored in the reception buffer of the storage section 22.

When the printout operation of the contents of the receive buffer is completed, P3
It is checked whether the next print data is being input to the I10 interface 27. And if it is done manually, P
Returning to step 2, it is checked whether the manually inputted print data is a code for immediately printing the contents of the above-mentioned receive buffer. If it is not such a code, there is no need to immediately print out the contents of the reception buffer, so the process returns to Pl and stores the print data in the reception buffer.

If the next print data is not input to the I10 interface 27 at P3, the timer section 23 is input at P4.
It is checked whether the elapsed time T measured by the timer exceeds a predetermined time TM. If the predetermined time TM is exceeded before the next print data is input, an H level circuit cutoff signal is sent from the output port 28.

When an H-level circuit cutoff signal is sent from the CPU 21 to the open collector buffer 29 via the output port 28, the open collector buffer 29 operates to reduce the potential of the output terminal connected to the base terminal of the switching transistor 18. drop to ground level. Then, the switching transistor 18 is cut off, and the second relay 1
The drive current of the No. 7 drive coil 17b is cut off, and the contact 17a of the second relay 17 is opened. When the contact 17a is opened, the drive current of the drive coil 13a of the first relay 13 is also cut off, so the contact 13a of the first relay 13 is also opened. As a result, power supply from the external power source to the power supply circuit 14 is cut off.

Therefore, from this point on, the printing device enters the power-off state.

Note that when the operator presses the push-button power cutoff switch 20 while the printing device is in operation, the base potential of the switching transistor 18 is forcibly dropped to the ground potential, so that the switching transistor 18 is cut off.

As a result, contact 1 of the first relay 13 is
3a is opened, and the printing device shifts to a power-off state.

After the printer is powered on by the operator pressing the power-on switch 16, when a series of print output operations for the print data manually entered from the host computer 26 is completed, a predetermined If no print data is input from the host computer 26 for a predetermined time TM, it is determined that the series of print output processes described above has been completed, and the power to the printing device is automatically shut off. Therefore, the operator must select the power-on switch I and ■ at the time of starting printout. Even if the user leaves this location after executing the 71st operation 17, there is no need to return to this location for the power-off operation after the printout is completed, so the negative +11 burden on the operator can be reduced.

In addition, when the printing operation process is completed, after a predetermined time TM has elapsed, C
Since the power is immediately cut off in response to a circuit cutoff command from the PU 21, power consumption can be reduced, unnecessary operating time can be eliminated, and the life of the entire device can be extended.

Furthermore, if the host computer 26 does not manually input print data for a predetermined time TM, the power to the printing device is automatically cut off, so there is no need to send out a power cut-off command from the host computer 26 again. Therefore, there is no need to change the control program on the host computer 26 side in order to automatically shut off the power to the printing device.

[Effects of the Invention] As explained above, according to the present invention, when the next print data is not input within a predetermined time from the time of printout using a relay, the power to the device itself is automatically turned off. I'm trying to block it. Therefore, it is possible to reduce the burden on the operator, reduce power consumption, and extend the life of the entire device.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing a printing device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the same embodiment, and FIG. 3 is a diagram showing a power supply circuit of a conventional printing device. 1.11...AC plug, 2.15...fuse,
4.14... Power supply circuit, 9.26... Host computer (external control device), 13... First relay, 1
3a, 17a--Contact, 13'b, 17 b--
・Drive coil, 16...Power on switch, 17...
- Second relay, 18... switching transistor (switching circuit), 20... power cutoff switch,
21... CPU, 22... Storage section, 23... Timer section, 24... Printing section, 27... I10 interface, 28... Output port, 29... Oven collector buffer.

Claims (1)

[Claims] A printer that has a power supply circuit that converts power input from an external power source into predetermined drive power and supplies it to each internal component, and uses a printing unit to print out characters based on print data input from an external control device. In the apparatus, a first relay having contacts interposed between the external power source and the power supply circuit; and a power-on switch connected between the output terminals of the external power source via a drive coil of the first relay; ,
a second relay having contacts inserted between both terminals of the power supply switch; a switching circuit inserted in a drive current supply path from the power supply circuit to the drive coil of the second relay; a timer unit that measures the elapsed time from the time of printout; and when this timer unit measures a predetermined time period before the next print data is input from the external control device, it issues a circuit cutoff command to the switching circuit. A printing device characterized in that it is equipped with a power cutoff means for sending out.