JPS63209870A - Printer device - Google Patents

Abstract

PURPOSE:To prevent malfunctions of an electronic circuit, by setting a data bus into a non-transferring state when a printer cover is opened. CONSTITUTION:When a printer cover switch 8 is opened, a CPU 1 performs a cover-open processing operation. First, the CPU 1 executes a printing command being processed, and sets a printer into a non-operative condition. Next, the CPU 1 sets the output of a writing inhibit signal INH to High in order to hold the content of a RAM 4, sets an interruption input terminal IRQO for an interruption input, simultaneously enabling an interruption, and enters a stopping mode. Therefore, all of an address bus, a data bus and the like for the CPU 1 are fixed in a non-transferring state, an erroneous operation is not performed even upon the reception of any pulsed nozzle except the terminal IRQO.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to processing when a printer cover of a printer device such as an electronic typewriter is opened.

[Conventional technology]

Conventionally, printer devices such as electronic typewriters, especially type-type printers that use a type wheel, etc., have a cover switch, etc. to identify the open/closed state of the printer cover.
For the purpose of replacing the type wheel, replacing the ribbon cassette, etc., or for thermal transfer printers, replacing the thermal head, or opening the ribbon cassette link force bar. Since the design is designed to resume printing, the operator must hold a stationary carrier on which various conductive metal parts, such as mechanical and electrical components such as ribbon cassette support members, motor paper pressers, etc. Many parts are mounted, and many of them have the possibility of being directly touched by the operator.

Therefore, the phenomenon that must be noted at this time is the effect of the instantaneous discharge of static electricity charged on the human body.For example, in a dry indoor environment, the value may reach several volts or more. Currently, in order to ensure the safety of the equipment and to prevent erroneous operation of the electronic circuits, improvements are being made throughout the equipment.

For example, electrically floating metals on a carrier are forcibly grounded and then connected to the chassis of the printer with a flexible metal plate, metals are connected using braided wires, and logic Examples include removing high frequencies and adding filters to the circuit.

Since these are essentially unnecessary for performing the basic functions of the device, they actually increase the cost of the device and lead to deterioration of reliability.

[The present invention has been made in view of the above problems to be solved by the invention, and the instantaneous discharge to the carrier portion, which is originally said to be most susceptible to the effects of static electricity, especially in a low humidity environment.

The present invention prevents incorrect operation of electronic circuits by appropriately handling static electricity, which is most likely to occur when these conditions combine, such as a carpeted room and the clothes worn by the operator. The aim is to prevent this from happening.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is an electrical block diagram implementing the present invention.

Here l is the CPU, for example ■ Hitachi's new HD63
03Y and 4 MHz crystal oscillator 2 generates I M
Performs Hz synchronization operation. The terminal MPOI is an input that sets the CPU operating mode, and in this case, the external ROM (Re
ad 0nly memory) and internal RAM (random access).
sMemory) is placed in a usable mode. 3 is a ROM in which various programs for executing the operation commands of the CPU 1 are stored, and 4 is a working RAM for executing the programs.

For this reason, the power supply of the RAM 4 is designed to be backed up by a battery 9. 5 is an LSI incorporating a gate array address decoder, an I10 port for printer control, a logic circuit for printer servo motor control, and a thermal head drive control logic circuit.
It is. The output of the gate array circuit 5 is used by a printer driver 6 to increase the width of the tag, the carrier drive motor of the printer, and the paper feed motor.

It drives the printer 7 including a head up/down motor, ribbon feed motor, and other solenoids.

8 is the printer cover switch and the CPUI interrupt terminal■
] is connected to.

The printer cover switch 8 responds to the behavior of the printer cover when opening and closing the printer cover when replacing the ribbon cassette, cleaning or replacing the thermal head, etc. It is "High" when the printer cover is open, and when it is closed. Maintains the “Low” level. Next, the related operations of the CPUI and the printer cover switch 8 according to the present invention will be described.

First, after the power is turned on and reset, the CPUI is set to the input side of the ini-switch 8. Thereafter, a normal printer control operation routine is executed. Next, when the printer cover switch 8 is opened by the operator, the output lead is “Lo”.
w'' is detected, and the CPU 1 performs the cover oven processing operation shown in FIG.

First, execute the print command being processed (SL), S2) set the printer to a non-printing state (S3), and then set the write inhibit signal INH output high in order to retain the contents of RAM4.
After setting it to h (S4), set the interrupt input terminal rr for interrupt input, and at the same time set the interrupt to Enable.
Enter "stop" mode (S5).

Therefore, since the address bus, data bus, etc. of CPU1 are all fixed in a non-transfer state (pass line is cut off), interrupt terminal rW is used to interrupt any pulse nozzles other than the terminal. Even if you receive it, you will not be able to think of getting into the wrong action.

〔Effect of the invention〕

As described above, by implementing the present invention, safety when an operator operates the carrier inside the printer and prevention of malfunction of electronic circuits can be achieved at low cost by effectively utilizing the printer cover switch. Further memorized RA
Protection of the contents of M is also reasonably achievable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a printer device according to an embodiment of the present invention, and FIG. 2 is a flowchart showing cover oven processing of the present invention. 1 ・・・・・・・・・・・・・・・・・・・・・・・・
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・・・・・・・・・Crystal oscillator 3 ・・・・・・
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・・・・・・・・・・・・・・・ ROM4 ・・・・・・
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・・・・・・・・・・・・・・・ RAM5・・・・・・
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・・・・・・・・・・・・・・・・・・Gate array circuit 6 ・・・・・・・・・・・・・・・・・・・・・
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・・・・・・・・・・・・・・・・・・Driver 7 ・
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・・・・・・・・・・・・・・・Printer 8・・・・・・
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...Printer cover switch 2nd section

Claims (1)

[Claims] (1) A printer device having a detection means for detecting that a printer cover is opened, and means for setting a data bus to a non-data transfer state when the detection means detects that the printer cover is opened.