JPS60209848A - Picture forming device - Google Patents

Abstract

PURPOSE:To grasp accurately the operation mode at the time, when program runaway occurs, to clear up easily causes of program runaway by storing the operation mode then. CONSTITUTION:A CPU1 continues to transmit runaway detection clear pulses to a runaway detecting circuit 6 in the normal state. If this clear pulse signal is broken, runaway of the CPU1 is detected, and a reset signal is transmitted immediately 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 then, the copy mode just before runaway is written in a storage area of a RAM5. Meanwhile, the runaway detecting circuit 6 clears the runaway detection signal when several runaway 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 image forming apparatuses such as electrophotographic recording apparatuses, the CPU, which is the central control unit that executes the control program operations, may run out of control due to various causes such as power line noise, static electricity noise, and instantaneous power interruption. There were times when I was in a dangerous situation.

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 service personnel inspect the vehicle at a later date, they are unable to accurately determine the operating mode when the runaway occurs, making it impossible to determine the cause and take appropriate action. This had the drawback of inviting a recurrence of the out-of-control behavior.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the conventional ones as described above, and to provide an image forming apparatus that can accurately determine the operating mode at the time of runaway as a material for elucidating the cause of computer program runaway. shall be.

[Structure of the invention]

The present invention provides an image forming apparatus whose operation is controlled by a computer, including program runaway detection means for detecting program runaway in the computer, and non-volatile memory for storing an operating mode at the time of program runaway detected by the program runaway detection means. It has a configuration comprising means.

[Embodiments of the invention]

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

FIG. 1 shows a control unit of an image forming apparatus according to the present invention, in which 1 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
13 is a nonvolatile RAM, 6 is a runaway detection circuit, and 7 is a reset circuit.

The CPU is the central processing unit of the computer, and controls the operation of the image forming apparatus, and also controls the copy mode (high voltage output, paper feeding,
When there is a change in the ADF operation, sorter operation, etc., a new copy mode is written to a predetermined storage area of the non-volatile RAM 5, and when the condition is normal, a runaway detection clear pulse (pulse with period T or less) is sent. It continues to be sent to the runaway detection circuit 6.

The runaway detection circuit 6 detects that the runaway detection clear pulse signal has been discontinued when no pulse arrives during the period T, that is, that the CPU has runaway, and immediately sends a CPU reset signal and resets the CPU. Following the throat signal, a runaway detection signal is output for a certain period of time.

Then, as shown in the flowchart of FIG. 2, when the CPU is reset by turning on the power switch, manually reset, or reset by the runaway detection circuit 6, the CPU executes an initial routine, and at that time, the runaway detection signal is output. If there is, the copy mode immediately before the runaway is written to the runaway storage area of the nonvolatile RAM 5, and if there is no runaway detection signal, the copy mode is not read from the nonvolatile RAM 5 and written to the runaway storage area. The copy operation routine is executed with .

As shown in FIG. 3, writing to the runaway storage area of the nonvolatile RAM 6 is performed by using 1 byte of 8-bit memory for each runaway event.

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 copy operation mode when the runaway of the CPU 1 occurs is written in chronological order.

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. The CPU then executes the initial routine in response to the reset signal and also detects the runaway detection signal, so the copy operation mode immediately before the runaway is written in the runaway storage area of the nonvolatile memory 5.

On the other hand, when the runaway detection circuit 6 receives several pulses of the detection clear pulse signal thereafter, it clears the runaway detection signal.

Further, the copy operation mode at the time of runaway occurrence written and stored in the non-volatile RAM 5 in this way is read out from the non-volatile memory 5 and displayed on the display section when the mode is set by input means such as a keyboard. Moreover, this mode setting can be performed at any time, not just immediately after the runaway occurs, so that the display on the display or the recording on the external recording means can be set. By looking at , you can know the copy operation mode at the time of runaway occurrence that has occurred up to that point.

Note that the present invention is not limited to the above embodiment (for example, the storage area of the non-volatile RAM 5 for writing the copy operation mode when the CPUI runs out is limited to 10 bytes for 10 times, and new data is written). Of course, if the storage area in which the data is stored overflows, all data addresses may be incremented to always store new data.

〔Effect of the invention〕

By configuring the present invention as described above, it is possible to automatically record the copy operation mode when a program runaway occurs, and therefore it is possible to accurately know the copy operation mode when a program runaway occurs even at a later date. This can be used as data to clarify the cause of runaway. For example, if runaway occurs while high voltage is being applied, it may be caused by a lightning strike, or 1. If a runaway occurs during ADF operation or sorter operation, it can be assumed that the runaway occurred due to static electricity noise at each location, so appropriate measures can be taken to prevent the runaway from occurring again. This has excellent effects such as making it possible to prevent accidents from occurring.

[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 the runaway storage area of the nonvolatile memory. 1-------- CPU U2----- ROM3
----RAM 4---------1/O port 5--Nonvolatile memory 6------Runaway detection circuit 7--------- Recessoto circuit patent applicant Konishiroku Photo Industry Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] +11 In an image forming apparatus whose operation is controlled by a computer, a program runaway detection means for detecting program runaway of the computer, and an operation mode at the time of program runaway detected by the program runaway detection means are stored. An image forming apparatus comprising a non-volatile storage means. (2) The image forming apparatus according to claim 1, wherein the nonvolatile storage means is a nonvolatile memory. (3) The image forming apparatus according to claim 2, wherein the operating mode at the time of program runaway stored in the nonvolatile memory is detected as necessary.