JPS60209847A - Picture forming device - Google Patents

Abstract

PURPOSE:To grasp accurately the date, when program runaway occurs and to analyze easily causes of program runaway by providing a program runaway detecting circuit. CONSTITUTION:A CPU1 continues to transmit runaway detection clear pulses to a runaway detecting circuit 7 in the normal state. If this clear pulse signal is broken, runaway of the CPU1 is detected, and a reset signal is transmitted to the CPU1, and a runaway detection signal is outputted for a certain period. When the CPU1 is reset, an initial routine is executed; and if the runaway detection signal is outputted in this case, the date of this output is read out from a calendar IC5 and is written in a prescribed storage area of a non-volatile RAM6. Meanwhile, the runaway detecting circuit 7 clears the runaway detection signal when several detection clear pulses are inputted thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus, and particularly to an image forming apparatus whose operation is controlled by a computer.

(Prior Art) In general, in an image forming apparatus such as an electrophotographic recording apparatus, the CPU, which is the central control unit that executes the control program operations, is affected by various causes such as power line noise, static electricity noise, and momentary power interruption. There were times when the vehicle spun out of control and became dangerously out of control.

For this reason, in the past, when the central control unit CPU went out of control, the external output was turned off or the central control unit CPU
There were some that ensured safety by resetting the PU.

However, with such conventional methods, it is difficult to identify the cause of the runaway after the fact, such as power line noise, static electricity noise, momentary power interruption, etc., and to remove the cause and prevent the runaway from happening again. In many cases, even if a service person inspects the vehicle at a later date, they are unable to accurately determine the date and time when the runaway occurred, making it impossible to determine the cause and causing the vehicle to run out of control without being able to take appropriate measures. This method has the disadvantage of causing recurrence of the problem.

[Purpose of the invention]

It is an object of the present invention to eliminate the drawbacks of the conventional ones as described above and to provide an image forming apparatus that can accurately determine the date and time of occurrence of a program runaway as data for elucidating the cause of a computer program runaway. .

[Structure of the invention]

The present invention provides an image forming apparatus whose operation is controlled by a computer, including means for detecting program runaway in the computer, and a nonvolatile memory for storing the date and time of occurrence of the program runaway detected by the runaway detecting means. have.

[Embodiments of the invention]

Embodiments of the invention shown in the drawings will be described below.

FIG. 1 shows a control section of an image forming apparatus according to the present invention, where l is a central processing unit, ie, a CPU, and 2 is a ROM.
, 3 is RAM, 4 is I10 boat IC which is input/output device
l3 is a battery-backed calendar IC16
7 is a nonvolatile RAM, 7 is a runaway detection circuit, and 8 is a reset circuit.

The CPU is the central processing unit of the computer, and controls the operation of the image forming apparatus, and when in a normal state, continues to send runaway detection clear pulses (pulses with period T or less) to the runaway detection circuit 7. ing. The runaway detection circuit 7 detects that the runaway detection clear pulse signal is interrupted when no pulse arrives during the period T, that is,
Detects that the CPUI has gone out of control and immediately shuts down the CPU.
In addition to sending a UI reset signal, a runaway detection signal is output for a certain period of time following the reset signal.

As shown in the flowchart of FIG. 2, when the CPU 1 is reset by turning on the power switch, manually reset, or reset by the runaway detection circuit 7, it executes an initial routine, and at that time, the runaway detection circuit 7 executes the initial routine. If there is a detection signal, the date and time at that point in time (current at that time) is read from the calendar lc5 and written into a predetermined storage area of the nonvolatile RAM 6, and if there is no runaway detection signal, the date and time at that time (current at that time) is read from the calendar IC5 and written into a predetermined storage area of the nonvolatile RAM 6. R
The copy operation routine is executed without writing to AM6.

As shown in FIG. 3, writing to the non-volatile RAM 6 uses 5 8-bit memories. For example, in the case of 13:46 on January 16, 1984,
Each byte contains the last two digits of the year “84”, the month “01”, and the day “
16', hour "13", minute "46" in order,
As a result, 13:46 on January 16, 1948 is written.

Also, when writing new data, select an address where no data has been written, and an address where data has already been written before that address.
The date and time of the CPUI runaway is written in the order in which it occurred.

Next, the operation of the above will be explained.

First, when the runaway detection clear pulse signal is interrupted while the CPUI is operating, the runaway detection circuit 7 detects this and immediately sends a reset signal to the CPUI and outputs a runaway detection signal. Then, the CPUI executes the initial routine in response to the reset signal and also detects the runaway detection signal, so it reads the date and time at that point from the calendar IC 5 and writes it into the nonvolatile RAM 6.

On the other hand, when the runaway detection circuit 7 receives several pulses of the detection clear pulse signal thereafter, it clears the runaway detection signal.

Furthermore, the data on the date and time of runaway occurrence written and stored in the non-volatile RAM 6 in this way is read out from the non-volatile memory and displayed on the display section when the mode is set using an input means such as a keyboard. , or recorded in the external recording means.Moreover, this mode setting can be done at any time, not just immediately after the runaway occurs, so if you look at the display on the display or the record on the external recording means, It is possible to know the date, time and frequency of runaway incidents that have occurred up to that point.

Note that, without being limited to the above embodiments, the CPU,
By limiting the storage area of the non-volatile RAM 6 for writing the date and time of runaway occurrence of 1 to 25 bytes for five times, for example, and erasing the oldest data if the storage area overflows when new data is written, Of course, it is also possible to always save new data.

〔Effect of the invention〕

By configuring the invention as described above, it is possible to automatically record the date and time when a computer program runaway occurred, and therefore, even at a later date, the date and time when the runaway occurred can be accurately recorded. It can be used as data to clarify the cause. For example, if a runaway occurs at a fixed time every day, a momentary power outage may occur because equipment with large power consumption connected to the same power line starts up at that time. This has an excellent effect in that it is possible to estimate whether a runaway will occur, and therefore to take appropriate measures to prevent the runaway from happening again.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the control section of an image forming apparatus according to the present invention, FIG. 2 is a flowchart of the main part,
FIG. 3 is an explanatory diagram of non-volatile memory. 1-・-CP U 2---------ROM3----
--- RAM 4----1/O boat 5----
---Calendar IC6--Nonvolatile memory 7--
-------Runaway detection circuit 8---------Reset circuit Fig. 1 Fig. 2 Completed dress F700st F2O3'' F2O3q F2O3・F2O3=- Fig. 3

Claims (1)

Scope of Claims (11) An image forming apparatus whose operation is controlled by a computer, including a program runaway detecting means for detecting a program runaway in the computer, and a non-volatile memory device for storing the date and time of occurrence of the program runaway detected by the program runaway detecting means. (2) The image forming apparatus according to claim 1, wherein the nonvolatile storage means is a nonvolatile memory. (3) The image forming apparatus comprises a nonvolatile storage means. 3. The image forming apparatus according to claim 2, wherein the date and time of occurrence of program runaway stored in the memory is detected as necessary.