JPH01241477A - Printer - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a heating or smoke emitting accident of a movable part, by interrupting the supply of a power to the movable part forcibly when a driving system is in a standby state. CONSTITUTION:When a sensor interrupt occurs, a microprocessor 1 judges whether a state flag 1a is in an operating state or not, and makes a return to a main routine when a standby state of a driving system is shown. When an operating state of the driving system is shown, a printing process is conducted by a printing head. When printing is executed normally, an alarm timer 1b is re-started to conduct a prescribed time count every time when a process of the sensor interrupt is conducted. It happens assumedly that output of a sensor signal is stopped with some cause, the sensor interrupt does not occur and the alarm timer 1b conducts the time count up to a prescribed value for a prescribed time. Then an alarm timer interrupt occurs when the prescribed value is reached by the time count. Then a drive signal from the microprocessor 1 is turned OFF, a switch means 7a of a drive circuit 7 is put in an OFF state forcibly, a supply of a power to a space motor is stopped, and thus the occurrence of heating and smoke emitting accidents of the space motor can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a printer that is frequently used as one of the peripheral devices for computers, word processors, and the like.

(Prior Art) Printers, which are often used as peripheral devices for computers and the like, receive data from the computer and print out various types of information.

FIG. 2 shows a block diagram of such a conventional printer.

The figure shows a microprocessor 1, a read-only memory (ROM) 2 connected to it, a random access memory (RAM) 3, a control circuit 4, an interface driver/receiver circuit 5, and a drive system. It consists of 6.

The microprocessor l is a circuit that controls and manages the entire printer. This circuit includes a status flag 1a consisting of a register for controlling power supply to the drive system 6, which will be explained later.
and an alarm timer 1b consisting of a counter. A ROM (read-only memory) 2 is a read-only memory in which programs, character font patterns, etc. are stored. A RAM (Random Access Memory) 3 is a memory in which data output from the control circuit 4 can be temporarily stored and read and written. The control circuit 4 is a circuit that controls and manages the interface driver/receiver circuit 5 and maintains the operation of the drive system 6. The interface driver/receiver circuit 5 is a circuit that exchanges data with a computer (not shown) or the like via an interface. Drive system 6
is composed of a drive circuit 7, a power supply 8, and a movable part 9. The drive circuit 7 is a circuit that controls the supply of power to the movable part 9. The power supply 8 is a circuit that supplies power to the movable part 9 via the drive circuit 7. The movable part 9 includes a print head 10, a space motor 11, a line feed motor 12, and a sensor section 13.

The print head 10 prints characters and the like on a printing medium such as printing paper (not shown). The space motor 11 is
This is a motor that drives the print head 10. Sensor part 13
is composed of a slit encoder 13a and a sensor 13b.

The slit encoder 13a is a disk-shaped plate that rotates in conjunction with the space motor 11 and has a large number of radial slits. The sensor 13b is the slit encoder 13
It is composed of a light emitting element and a light receiving element, which are arranged opposite to each other so as to sandwich a. These slit encoders 13a
The rotation of the space motor 11, that is, the amount of movement of the print head 10 can be recognized by the sensor 13b. Finally, the line feed motor 12 is a motor that drives a platen (not shown).

The operation of the printer with the above configuration will be explained.

First, when power is turned on to microprocessor 1, R
Read and execute the program from OM2. By executing this program, the printer undergoes initial processing.

That is, the microprocessor 1 issues an initial setting operation command to the control circuit 4 and the drive circuit 7, checks the interface driver/receiver circuit 5, and sets the drive system 6 to a state where printing operation can be performed at any time. This state will be referred to as a drive system standby state (a state in which the status flag 1a is O).

With this, when data is sent from a host system (not shown) connected to the interface driver/receiver circuit 5, the printing operation can be started immediately.

That is, when data is received from a host system (not shown) connected via the interface driver/receiver circuit 5, this data is stored in the RAM 3 via the control circuit 4. And microprocessor 1 has RAM
When the print start control code is recognized from the data stored in 3, a print operation command is issued to the drive circuit 7, and the drive system 6 is operated. This state will be referred to as the drive system operating state (state where the state flag 1a is 1). This driving system operating state refers to a state in which printing is just being performed based on the print data stored in the RAM 3.

That is, a drive signal is output from the input/output port of the microprocessor 1 to the drive circuit 7. Then, the drive circuit 7 supplies power from the power supply 8 to the space motor 11 based on this drive signal, and scans the print head 10. On the other hand, microprocessor 1 is
The position of the print head IO and the rotational speed of the space motor 11 are controlled by signals from the slit encoder 13a and the sensor 13b (referred to as sensor signals), which rotate in conjunction with the space motor 11. At the same time, the microprocessor 1 recognizes the printing timing based on the signals from the slit encoder 13a and the sensor 13b, and
Based on the print data stored in AM3, a corresponding character font pattern is read out from the character font patterns stored in ROM2. Then, a head signal for printing is input to the print head 10 via the drive circuit 7, and the data stored in the RAM 3 is sequentially printed.

When the printing of one line of print data stored in the RAM 3 is completed, the microprocessor 1 stops outputting the drive signal to the drive circuit 7, stops the space motor 11, and uses the line feed motor 12 to print one line of print data. Perform a line break.

Now, in the above printing operation, for example, when the drive system 6 is in an operating state, that is, when performing a printing operation, the space motor 11 may An abnormal situation may occur in which the rotation of the machine is blocked. In this case, since the rotation of the slit encoder 13a also stops like the space motor 11, the microprocessor 1 cannot detect the output signal of the sensor 13b. If this state is left unattended, the space motor 11 will generate heat and furthermore, a smoke accident will occur. Therefore, while the microprocessor 1 is outputting a drive signal to the drive circuit 7, that is, the drive system is operating when power is supplied to the space motor 11, the microprocessor 1 is configured to keep the sensor signal from the sensor 13b for a predetermined period of time. When the alarm timer 1b provided in the microprocessor 1 recognizes that the detection is not detected, the output of the drive signal is stopped. As a result, the drive circuit 7 cuts off the power supply to the space motor 11.
The drive system 6 is forced into a standby state.

(Problem to be Solved by the Invention) Conventionally, when an abnormal situation occurs while the drive system 6 is in an operating state, the microprocessor 1 recognizes it and prevents a secondary accident from occurring. was prevented.

However, the environment in which these printers are installed is not always good, and they are sometimes installed in quite harsh locations. Furthermore, these printers are particularly exposed to noise voltage and static electricity from an input power source, as well as temperature, humidity, vibration, etc., which may cause malfunctions of the microprocessor 1 and peripheral circuits.

Once a printer is powered on, its drive system 6 is generally in a standby state longer than in an operating state. However, in the conventional printer, an abnormal situation is recognized only when the drive system 6 is in an operating state, and when the printer is in a standby state, it is vulnerable to malfunctions of the microprocessor 1 or circuit elements.

Therefore, power is erroneously supplied to the drive system 6 in the standby state,
Moreover, if an abnormal situation occurs in the drive system 6, no protection measures are provided.

The present invention has been made with attention to the above points, and an object of the present invention is to provide a printer in which circuit elements, etc. are not damaged due to an abnormal situation that occurs when the drive system is in a standby state. .

(Means for Solving the Problems) A printer of the present invention has a drive system operating state in which a drive system having a mechanically movable part is operating and a drive system standby state in which the drive system is not operating. In,
a status flag that distinguishes and displays the drive system operating state and the drive system standby state; and if the status flag indicates the drive system operating state, after the movable parts of the drive system have stopped operating; If the power supply to the movable parts of the drive system is forcibly cut off after a certain period of time and the status flag indicates the drive system standby state, the power supply to the movable parts of the drive system is cut off. It has power control means for forcibly cutting off the supply.

(Function) When the drive system is in standby mode, the above printer repeatedly forcibly cuts off the power supply to the movable parts. can be avoided.

(Embodiment) FIG. 1 is a block diagram of main parts of a printer of the present invention.

The block diagram in FIG. 1 shows in detail the portions corresponding to the microprocessor 1 and drive system 6 in the conventional block diagram shown in FIG.

In the printer of the present invention shown in FIG. 1, a status flag recognition means 2.degree. and a power supply control means 25 are newly provided in the microprocessor l, compared to the conventional printer explained using FIG. The other parts have the same configuration as in FIG. 2.

Now, the status flag recognition means 20 of the processor 1 in FIG.
is a state where the value of status flag 1a is 0 (drive system standby state)
It is a means for recognizing the power supply control means 25 and operating the power supply control means 25, and is composed of a logic circuit and the like. The power supply control means 25 is connected to the drive system 6
The drive circuit 7 is controlled to be in an OFF state, that is, a state in which power is not supplied to the movable part 9 thereof.

The processor 1 is provided with a status flag 1a and an alarm timer 1b, similar to the conventional printer shown in FIG.

The status flag 1a is a flag indicating the operating status and standby status of the drive system 6. The alarm timer 1b is a counter that measures a predetermined time.

Further, the drive system 6 similarly includes a drive circuit 7, a power source 8, and a movable part 9. In the drive circuit 7,
A switch means 7a and a power source 8 are provided, and the switch means 7
This is a circuit that controls power supply to the movable part 9 by turning on or off a. The movable portion 9 is provided with a print head, a space motor, and a line feed motor (not shown), and is further provided with a sensor section 13 consisting of a slit encoder and a sensor (not shown).

The operation of the printer with the above configuration will be explained using FIG. 3. FIG. 3 is a flowchart showing the operation of the printer of the present invention.

First, when the power is turned on to the printer shown in Figure 1,
Initial processing such as setting O to the status flag 1a is performed (step Sl). Then, the status flag recognition means 20 determines whether the value of the status flag 1a is 1 (step S2). If the result is No, that is, if the drive system 6 is in a standby state, the process moves to step S3. step s
3, the power supply control means 25 of the microprocessor 1 is operated to forcibly set the switch means 7a of the drive circuit 7 to the OFF state (step S3). For this reason,
No power is supplied to the movable part 9 of the drive system 6, and no operation is performed.Next, the process moves to step S4, and the interface driver/receiver circuit 5 (FIG. 2)
It is determined whether data has been input (information received) (step S4). If YES in step S2, the process jumps to step S4. If the result of step S4 is NO, it is determined whether an operation switch (not shown) for manually operating the drive system 6 has been turned on (
Step S5). If this result is No, step S6
Move to. In step S6, it is determined whether or not to start printing the data stored in the RAM 3 (step S6).

If the result is No, the process returns to step S2. Therefore, when the drive system 6 is in the standby state, steps S2, S3, and S4
, S5, S6, and returns to step S2.

Now, if the result of step S4 is YES, that is, the ink face driver/receiver circuit 5 (second
If there is data input in Figure), the process moves to step S7. In step S7, the data input to the interface driver/receiver circuit 5 is transferred to the RAM via the control circuit 4.
After performing the reception process stored in step S2, the process returns to step S2. Next, if a YES result is obtained in step S5, that is, if the operation switch is turned on, the process moves to step S8. In step S8, the drive system 6 is controlled by the control circuit 4 in response to the operation switch to operate the movable part 9, and then the process moves to step S2.

If the result of step S6 is YES, the process moves to step S9. In step S9, a drive signal is output from the microprocessor 1 to the drive circuit 7,
The switch means 7a is turned on. Next, the alarm timer 1b of the microprocessor 1 is started to measure time.

Then, the status flag 1a is set to 1. This results in
The drive system 6 is now set to the operating state.

According to the flow described above, the drive system 6 changes from the standby state to the operating state when the power of the printer is turned on.

Now, when the above flow of operations is performed, a sensor signal is output from the sensor section 13 of the movable part 9, and when it is recognized by the microprocessor 1 via the drive circuit 7, a sensor interrupt occurs.

FIG. 4 shows a flowchart of sensor interrupt.

Hereinafter, the flow of the flowchart explained in FIG. 3 will be referred to as the main routine.

When a sensor interrupt occurs, the microprocessor 1 determines whether the status flag 1a is 1 (step 5I).
O). If the result is No, that is, if the status flag 1a indicates the drive system standby state, the process returns to the main routine. If the result is YES, that is, if the status flag 1a indicates the drive system operating status, the process moves to step Sll. In step Sll, it is determined whether printing of the data in the RAM 3 has been completed. If the result is No, the process moves to step S12. In step S12, the print head 10 performs a printing process to print on the print paper, and the process moves to step S13.

In step S13, the alarm timer 1b is restarted to return to the main routine. Now, if the result of step Sll is YES, that is, RA
When printing of the data of M3 is completed, step S14
Move to. In step S14, the alarm timer 1b is stopped and reset. Then, the drive signal from the microprocessor 1 is turned off, the switch means 7a of the drive circuit 7 is turned off, the operation of the space motor 11 is stopped, and the process returns to the main routine.

Thereafter, the print end control code is stored in the RAM 3, and similar operations are repeated until it is recognized by the microprocessor 1.

Now, when printing is being performed normally by the print head 10, the alarm timer 1b is restarted every time a sensor interrupt is processed, so that the predetermined time measurement is performed, that is, the alarm timer 1b is not in a reset state. . However, the sensor interrupt is performed based on a sensor signal from the sensor section 13. Therefore, if the space motor 11 stops rotating for some reason, the slit encoder 13a will stop rotating and no sensor signal will be output.

As a result, no sensor interrupt occurs, and the alarm timer 1b measures a predetermined value for a certain period of time. When the alarm timer 1b measures a predetermined value, an alarm timer interrupt occurs.

FIG. 5 shows a flowchart of alarm timer interrupt.

When an alarm timer interrupt occurs as shown in the figure, the drive signal from the microprocessor 1 is turned off (step 515). As a result, the switch means 7a of the drive circuit 7 is forcibly turned off, and the space motor 11
The supply of power to the space motor 11 is stopped, thereby preventing the space motor 11 from overheating and causing smoke.

Now, a case will be described in which the switch means 7a of the drive circuit 7 is turned on even though the status flag 1a is in the O state for some reason.

This state indicates an abnormal situation in which the drive system 6 is in a standby state according to the status flag 1a, but the drive system 6 is actually in an operating state.

In this case, as shown in FIG. 3, it is determined in step S2 whether the status flag 1a is 1 or not. In this case, since the result is No, step S3 is executed. Step S3
Now, as described above, in order to forcibly turn off the switch means 7a of the drive circuit 7, the power supply to the space motor 11 is cut off. As a result, if the drive system 6 is supposed to be in the standby state according to the status flag 1a, but in reality the drive system 6 is in the operating state, the drive system 6 is immediately activated as indicated by the status flag 1a. The state can be canceled.

As explained in FIG. 3, the process of forcibly turning off the switch means 7a of the drive circuit 7 (step S3)
is steps S2, S3, S4, S5, S6, and S
Since the process is repeated - times every time a loop such as 2 is passed, the process is repeated as long as the status flag 1a indicates the standby state of the drive system 6.

The printer of the present invention is not limited to the above embodiments.

FIG. 6 shows a flowchart of another embodiment according to the present invention.

Usually, in addition to the alarm timer 1b provided in the microprocessor 1, a printer is provided with a drive timer for setting the drive time of the space motor 11 of the movable part 9 and the line feed motor 12. If the main routine shown in FIG. 3 is being executed, this drive timer interrupt is generated and the drive timer is restarted.

When the drive timer interrupt occurs, the microprocessor 1 determines whether the drive system 6 is in an operating state (step 520). If the result of step S20 is No,
The process moves to step S21. In step S21, the switch 7a of the drive circuit 7 is turned off to cut off the power supply to the movable part 9, and the process moves to step S22. In step S22, the drive timer is restarted and the process returns to the main routine. If the result of step S20 is YES, the process moves to step S23.

In step 23, the movable part 9 is
Power is supplied, normal operation is performed, and the process moves to step S22.

As described above, abnormal situations can be avoided by determining whether or not the drive system 6 is in an operating state each time power is supplied from the drive circuit 7 to the movable part 9.

Also, the medium for forcibly cutting off the power is Space Motor 1.
1, the entire movable part 9, and the microprocessor 1.
It can also be used for parts that would be difficult to operate without such control.

(Effects of the Invention) The printer of the present invention configured as described above repeatedly forcibly cuts off the power supply to the movable parts when the drive system is in a standby state, so that when the drive system is in an operating state, It is possible to prevent accidents such as heat generation and smoke generation of movable parts due to such failures, not only in the case of such failures, but also in any case.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts related to the printer of the present invention, and FIG.
Figure 3 is a block diagram of a conventional printer, Figure 3 is a flowchart showing the operation of the printer of the invention, Figure 4 is a flowchart of sensor interrupts in the printer of the invention, and Figure 5 is an alarm timer according to the invention. Flowchart of Interruption FIG. 6 is a flowchart showing the operation of another embodiment of the present invention. 1... Microprocessor, la... Status flag,
1b...Alarm timer, 6...Drive system, 7...
Drive circuit, 7a... Switch means, 8... Power supply, 20... Status flag recognition means, 25... Power supply control means. Patent applicant: Oki Electric Industry Co., Ltd. Figure 1: Akira Kimoto's flowchart Figure 3: Flowchart of WA transmission H Figure 4: Flowchart of alarm interrupt Figure 5

Claims (1)

[Scope of Claims] A printer having a drive system operating state in which a drive system having a mechanically movable part is operating, and a drive system standby state in which the drive system is not operating, wherein the drive system operating state and the drive system standby state include the following: a status flag that distinguishes and displays a standby state of the drive system; and if the status flag indicates the operating state of the drive system, the drive system is activated after a certain period of time has elapsed since the movable parts of the drive system stopped operating; Forcibly cut off the power supply to the movable part of the drive system, and if the status flag indicates the drive system standby state, forcibly cut off the power supply to the movable part of the drive system. A printer characterized by having a power control means.