JPH03277578A - Printer - Google Patents

Abstract

PURPOSE:To prevent the erroneous operation or printing due to the discharge of static electricity generated at the time of the cover open state of a printer by receiving printing data from a printing request part only during a period when the cover of the printer is in a closed state to output all of them and resetting the printer to an initial state unconditionally when the cover of the printer further becomes an open state after output and subsequently receiving the next printing data from the printing request part to output the same. CONSTITUTION:On the side of a printer 100, printing data are received during a period when a printer cover 180 is closed and the output of all of the received printer data is completed. Thereafter, when the printer cover 180 is opened, the printer 100 is reset to an initial state unconditionally. The erroneous operation (reckless driving) and erroneous printing of the printer 100 due to the static electricity discharged when the printer cover 180 is opened are prevented. Even when the internal data of a CPU 110 is destructed by any factor other than the discharge of static electricity at the time of the opening and closing operation of the printer cover 180, the CPU 110 has the inferiority self-detection function due to a watch dog circuit 140.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printer, and more particularly to a printer having a function of preventing malfunctions caused by static electricity discharged when a printer cover is opened.

[Prior Art] A printer prints out print data to be printed out, which is transmitted from a device connected to an upper level, in a predetermined format. In this case, the CPU ((C
Print data generated under the control of the PU (abbreviation for central processing unit) (hereinafter referred to as main CPU) is transmitted at high speed to the printer via a data bus. However, compared to this data transmission speed, the print output operation speed of a printer is slow, so a print buffer is installed on the printer side to temporarily store the transmitted print data.
The stored print data is sequentially printed out under the control of the printer's CPU. That is, the print buffer provided on the printer side is provided as a memory for buffering the difference between the print data transmission speed from the main CPU and the print pressure speed of the printer.

By the way, as mentioned above, in the print data control method of a conventional printer, the print data transmitted from the main CPU of the host device is temporarily stored in the print buffer, and the data is printed out in order from the data received first. Some printers operate to continue printing even if a printer cover that covers the print output section of the printer is opened during print output.

On the other hand, the print data transmitted from the main CPU as described above is sequentially printed out via the print buffer, but if the printer cover is opened during the printing operation, the printout operation in progress is immediately interrupted. Some printers resume the interrupted printing operation in response to the printer cover being closed. The print data stored in the print buffer when the print output operation is interrupted is stored and protected in the print buffer until the print operation is resumed.

[Problems to be Solved by the Invention] However, in the conventional printer as described above, when the printer cover is opened during printout operation, static electricity from the body may be discharged to the metal part of the printer unit. In this case, the discharged electrostatic energy may cause the CPU installed in the printer to malfunction, or the print data stored in the print buffer may be destroyed. There has been a problem in that the printer produces incorrect print output and print operations.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a printer that can prevent malfunctions and printing errors caused by static electricity discharged when a cover covering the printer is opened during a printout operation.

[Means for Solving the Problems] A printer according to the present invention is a printer that prints out print data transmitted following the print request in response to a print request, and in detail, prints out print data that is transmitted following the print request. a printing means for outputting; a detection means for detecting an open/closed state of a cover covering the printing means; a print control means for controlling the printing output; and further, in response to the detection means detecting that the printer cover is open while the print control means is printing the received print data, and means for setting the printing control means to an initial state.

[Operation] Since the printer according to the present invention is configured as described above,
If the printer cover is opened during the printing operation of the printer, the printer is prevented from receiving a print request and the data to be printed, and furthermore, the initial state setting of the printer is performed after printing all the received print data. Therefore, even if static electricity is discharged from the human body when the printer cover is open, there will be no print data to be printed out, so there will be no erroneous printing.Furthermore, the printer itself will be reset to its initial state. Printing operations are also performed normally after the printer cover is closed.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

The printer in this embodiment regards the main CPU (not shown) of a device connected to an upper level via a bus (not shown) as the print request source, and sends a print data transmission request ( It is assumed that a printout operation is started in response to receiving a signal (hereinafter abbreviated as transmission REQ).

FIG. 1 is a schematic diagram showing the internal functional configuration of a printer 100 according to an embodiment of the present invention.

In the figure, a printer 100 is connected to a print request source device 200, which is a host device. Further, each of the internal circuits is integrally covered and protected by a housing cover as shown in the figure.

A printer cover 180 that can be opened and closed from the outside is provided near the printing section 160 (described later) of the housing cover.

The printer cover 180 covers the printing section 16 of the printer.
It is opened and closed from the outside, such as when replacing 0 printing paper.

The internal functions of the printer 100 are controlled by a CPUll01 that controls and monitors the operation of the printer 100 itself.
ROM (Read 0nly) stores data (including programs) required for the processing operation of 0nly itself in advance.
Memory) 120, a print buffer 130 for temporarily storing print data, a watchdog circuit 140,
It includes a printing section interface circuit 150, a printing section 160, and a switch 170.

The watchdog circuit 140 is a type of timer,
It is provided to detect a defect in the CPUI 10. In other words, the timer of the watchdog circuit 140 is
When the timer is operating normally, the CPU 110 executes a program that is always reset once every certain period of time and prevents the timer from timing up. Therefore, if the timer reset program is not executed by CPUll0 for a certain period of time or more, a time-up alarm is output. In other words, the watchdog circuit 140 is a circuit that, unless its state is periodically reset by the CPU 10, gives an alarm signal to the CPU 110 to make it recognize that it is in a defective state.

Since the CPU 10 accepts the alarm signal given from the watchdog circuit 140 as an interrupt signal, the series of processes being executed at the time of receiving the alarm signal is interrupted and controlled to unconditionally return to the initial state.

Further, the printing unit 160 has a function of mechanically outputting print data on printing paper, and the printing unit interface circuit 150 is capable of outputting print data read from the print buffer 130 based on the control of CPUll0. It has a function of converting into an electrical signal and providing it to the printing section 160.

The switch 170 detects the open/closed state of the printer cover 180 and provides it to the CPU 10 as a signal S1. Specifically, during the period in which the switch 170 detects that the printer cover 180 is in the closed state, the switch 170 sets the signal S1 to the level "L".
When the open state is detected, the signal S1 is set from the level "LOW" to "HIGH" and output.

The printer 100 is configured as described above, and print data is sent from the print request source device 200 which is a host system.
It receives the print data transmitted following the EQ signal, and accordingly converts the received print data so that it can be printed out to the printing section 160 and outputs the data. However, when CPUll0 receives the transmission REQ signal, the signal level of signal S1 is “
LOW”, the print request source device 2 sends a transmission REQ signal acknowledgment (hereinafter referred to as a transmission ACK signal).
00, but on the contrary, the signal level of signal S1 is “H”.
IGH”, the printer operates so as not to transmit the transmission ACK signal to the print request source device 200.

In other words, even if the printer 100 receives the transmission REQ signal from the print request source device 20O, the printer cover 180
While the is open, the transmission ACK signal is not outputted, and the print data output request from the print request source device 200 is set in a waiting state.

FIG. 2 is a schematic processing flow diagram during printing operations of the print requesting device 200 and the printer 100 according to an embodiment of the present invention.

The illustrated processing flow on the printing request source device 200 side is stored in advance as a program in a memory (not shown) in the device ff 1200, and is executed under the control of the main CPU. Similarly, the illustrated processing flow on the printer 100 side is stored in advance in the ROMI 20 as a program, and is executed under the control of the CPUll0.

First, the print data transmission process on the print requesting device 200 side will be explained.

The main CPU of the print request source device 200 first repeats the process of step 5100 (abbreviated as 5100 in the figure) until print data to be printed out to the printer 100 is generated by various processes executed by the device 200. That is, the main CPU processes the application program registered in the print request source device 200, and when it determines that the printout of the print data is specified, it moves to the next step 5200.

In the process of step 200, the above-mentioned step 51
In response to the determination that print data 00 is present, a transmission REQ signal is sent to the printer 100 to start printing out the print data.

After that, the next step 5300 is performed by the printer 100.
The process is repeated until a transmission ACK signal is received. In other words, in response to receiving the transmission REQ signal, the printer 100 side transmits a transmission ACK signal to the print requesting device 200 (details will be described later), so the main CPU checks whether or not this transmission ACK signal has been received in step 5300. It is determined by the process.

Upon receiving the transmission ACK signal from the printer 100 in the process of step 5300, the next step 54 is performed.
00 processing, and print data designated for output by the above-described application program processing is transmitted at high speed to the printer 100 via the bus.

After sending the print data in the process of step 5400,
The process returns to step 5100 again, and the process for the next generated print data designated for print output is repeated in the same manner.

As described above, the main CPU on the print request source device 200 side
Since the loop process consisting of steps 5100 to 5400 is repeated every time print data to be printed is generated, the transmission and reception process of the send REQ signal and the send ACK signal is performed on the printer 100 side each time this print data is transmitted. It is held between.

Furthermore, even after sending the transmission REQ signal, the printing requesting device 200 side recognizes that it has not been given permission to send print data until it receives a transmission ACK signal from the printer 100 side, and sends the print data to the printer 100 side. Set the print data transmission to standby mode.

Next, a description will be given of print data reception on the printer 100 side and print output processing of the received print data, which is executed in parallel with the process on the print request source device 200 described above.

First, in the process of step 5250, CPUll0 performs the process step 5200 on the print requesting device 200 side.
It is determined whether or not to receive the transmission REQ signal transmitted at. This determination process is repeated until the transmission REQ signal is received, but once the transmission REQ signal is received, the process moves to the next step 5270, and the subsequent processes are started.

In the process of step 5270, the above-mentioned step 5250
In response to receiving the REQ signal sent by
80 is closed. That is, the open/close state of the printer cover 180 is detected by the switch 170, and the detection result is sent as the signal S1 to the CPUll0.
Therefore, the CPU 110 determines whether the signal level of the signal S1 is "HIGH" or "LOW" and determines whether the printer cover 180 is currently closed or closed. For example, if the signal S1 is at the signal level “HI”
GH'' (printer cover 180 is in the open state), the process of step 5270 is repeated, but the signal S1 or the signal level is “LOW” (printer cover 180 is in the open state).
0 is the closed state), the process proceeds to the next step 52
90.

In step 5290, step 5250 described above
In response to receiving the transmission REQ signal in the process of step 5270 and determining that the printer cover 180 is in the closed state, a transmission ACK signal is transmitted to the print request source device 200 to transmit the print data. Process to encourage.

In this way, the transmission ACK signal transmitted from the printer 100 side is received in processing steps 5300 and 5400 on the print requesting device 200 side described above, and the print data is transmitted to the printer 100 side. Therefore, the CPU 10 can receive the print data in the processing of step 5410 and the step knob 5450 and temporarily store it in the print buffer 130.

Note that, as described above, the print buffer 130 is a memory provided to buffer the speed difference between the data transmission speed and the printing speed, so its storage capacity is large enough to store the amount of print data of about 2 to 3 lines in the print section 160. It's good.

In the process of the next step 5500, the print data stored in the print buffer 130 in the process of step 5450 described above is converted into an electrical signal via the print unit interface circuit 150, and is applied to the print unit 160 to be printed out. Process. At this time, the print buffer 13
All print data stored in 0 is printed out.

Thereafter, in the process of the next step 5550, it is determined whether the printer cover 180 is in the closed state in the same manner as the process of step 5270 described above. As a result of this determination, if the printer cover 180 is in the closed state, the process returns to step 5250 again, and thereafter, the next print data transmission/reception process and the output process of the received print data are executed in the same manner.

On the other hand, if it is determined in the determination process of step 5550 that the printer cover 180 is open, the process moves to the next step 5600.

In the process of step 5600, the above-mentioned step 5
Upon receiving the determination result of step 550, the printer 100 is reset to the initial state. That is, since it was determined in step 5550 that the printer cover 180 is in the open state, electrostatic discharge from within the body when the printer cover 180 is in the open state causes temporary storage in the internal buffer, register, stack, etc. of the CPU 110. There is a possibility that the data may be destroyed (logic destruction). To this end, when CPUll0 detects that printer cover 180 has been opened after printing in step 5500, it unconditionally resets printer 100 to its initial state.

In other words, once the printer cover 180 is opened, CPUll0 resets the initial values to the print buffer 130 and the internal buffers, registers, and stacks of the CPU 10, resulting in the aforementioned data destruction (logic destruction).
This prevents malfunction (runaway) of the CPUll01, that is, the printer 100 itself.

Thereafter, in the process of step 5650, the open/closed state of the printer cup-180 is determined in the same manner as in step 5270 described above.

At this time, the process of step 5650 is repeatedly executed while the printer cover 180 is in the open state, but once the printer cover 180 is in the closed state, the process returns to step 5250 again. The printout process is repeated.

As shown in the processing from step 5550 to step 5650, in response to the printer cover 180 being opened and then closed, the process returns to step 5250, but all the various data stored in CPUll0 are initialized. Since the state has been reset, step 5
The next print data processing shown after 250 can also be executed normally (without malfunction).

Furthermore, since the print data received and stored in the print buffer 130 is completely output in the print output process of step 5500 described above, the printer cover 180 is
Even if the print buffer 130 is opened and electrostatic energy is released, there is no print data left in the print buffer 130 to be output (
(reset to the initial state), the print data will not be destroyed.

As described above, on the printer 100 side, print data is received while the printer cover 180 is closed, all of the received print data is outputted, and when the printer cover 180 is opened thereafter, the print data is unconditionally applied. By resetting the printer 100 to its initial state, malfunction (runaway) of the printer 100 and erroneous printing due to static electricity discharged when the printer cover 180 is opened are prevented.

In addition, even if the internal data of CPU110 is destroyed due to some reason other than electrostatic discharge when the printer cover 180 is opened/closed, the CPU10 has a self-failure detection function by the watchdog circuit 140 as described above. Therefore, the alarm signal given from the watchdog circuit 140 is accepted as an interrupt signal, and the process proceeds to step 5600.
Execute the reset operation to the initial state as described in the process. Therefore, even if the CPU 10 goes out of control due to internal data being destroyed, the watchdog circuit 140 can perform self-diagnosis and self-recovery, making it possible to recover the printer 100 from an abnormal state at the same time. can.

Note that the above-mentioned watchdog circuit 140 operates to
Even if PUll0 recovers by itself, all the circuits remain in an operable state, so paper feeding operation is possible with the printer cover 180 open.

[Effects of the Invention] According to the present invention, print data is received from the print request source only during the period when the printer cover is in the closed state, and all print data is output. After resetting to the initial state, the next print data is received from the print request source and output, which has the effect of preventing malfunctions and incorrect printing caused by static electricity being discharged when the printer cover is open. There is.

Further, even if the printer malfunctions, there is an effect that the self-recovery function allows the printer itself to be reset to the initial state and recovered at the initial stage.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the internal functional configuration of a printer according to an embodiment of the present invention. FIG. 2 is a schematic processing flow diagram of the printing operation of the printing requesting device and the printer according to an embodiment of the present invention. In the figure, 100 is a printer, 110 is a CPU, 13
0 is the print buffer, 140 is the watchdog circuit, 16
0 is a printing unit, 170 is a switch, 180 is a printer cover, 200 is a print request source device, and Sl is a signal.

Claims (1)

[Claims] In a printer that prints out print data transmitted following the print request in response to a print request, the printer includes: a print means for outputting the print data; and a detection means for detecting an open/closed state of a cover covering the print means. , a print control means for receiving the print data and controlling the print data to be output entirely to the print means in response to the detection means detecting that the printer cover is in the closed state; and means for setting the printing control means to an initial state in response to the detection means detecting that the printer cover is in an open state while printing the print data.