JPH0237438A - Copying device - Google Patents

Abstract

PURPOSE:To prevent trouble and disasters due to the malfunction by judging a CPU to be abnormal to reset it at the time of detecting that a clock signal is not outputted from a communication means over a prescribed time. CONSTITUTION:An MB3773 is an IC (reset means 14) to monitor the voltage of a power source incorporated in a watchdog timer, and this IC outputs a reset signal when an input CK is not outputted over a set time or the voltage of the power source is reduced to a certain voltage of lower. This reset output is connected to reset terminals of CPUs 13, 7 and 1. Consequently, all CPUs can be reset and restarted when the operation of any CPU is abnormal. Thus, trouble and disasters due to the malfunction are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a copying machine having a plurality of CPUs, and particularly to a control device thereof.

[Conventional technology]

In recent years, copying apparatuses have become more multi-functional, and it has become common to use multiple CPUs for controlling the copying apparatus, for example, one for optical system control and one for copy sequence control. By the way, if an abnormality occurs in the program stored in the ROM in the CPU and the CPU goes out of control, the copying machine will be in a dangerous state.

Therefore, conventionally, control has been performed to prohibit copying operations when an abnormality occurs in the CPU.

[Problem to be solved by the invention]

Conventional abnormality detection methods include a method in which multiple CPUs monitor each other, or a method in which an external abnormality detection IC is provided and the CPU resets the IC at certain intervals. , in the case of monitoring between CPUs, it is effective only when only one of them is abnormal.

Furthermore, in the case of an external IC, hardware for the output port is required because conventionally a CPU controls a specific output port and outputs a reset output. In addition, one IC is required to detect an abnormality in one CPU, and as many ICs as there are CPUs must be provided, resulting in an increase in cost.

The present invention solves the above-mentioned drawbacks of the prior art, and provides a copying machine that can easily and accurately detect an abnormality in the copying machine caused by a CPU runaway, and prevent failures due to malfunctions by prohibiting the copying operation. The purpose is to provide.

[Means to solve the problem]

To this end, in the present invention, at least one abnormality detection means detects abnormalities in a plurality of CPUs and prohibits copying operations, thereby preventing failures and the like.

More specifically, a plurality of C
In a copying apparatus having a PU and means for communicating data between the respective CPUs, during normal operation of the program, a clearing clock signal is received from the communication means, and on the other hand, a clock signal for clearing is received from the communication means for a predetermined time set longer than the communication interval time. The present invention is characterized by comprising a reset means for detecting an abnormality and resetting the CPU when the clock signal is not output from the communication means.

[Effect]

According to the present invention, if a clock signal is not output from the communication means for a predetermined period of time or more, it is determined that the CPU is abnormal, and a reset is applied to prevent failures and disasters due to malfunctions.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 is an internal mechanism diagram of a copying apparatus according to an embodiment of the present invention. A contact glass 40 on which a document is placed is provided on the upper surface of this copying apparatus, and an optical scanning system is provided below the contact glass.

The optical scanning system includes an illumination 41, a first mirror 42, a second mirror 43, a third mirror 44, a zoom lens 45, a fourth mirror 46, and the like. The optical scanning system is mechanically driven to scan in the sub-scanning direction, that is, in the horizontal direction of the drawing, while irradiating the photosensitive drum 47 with light corresponding to the original image. In this example, the magnification of the original image in the main scanning direction, that is, the direction perpendicular to the drawing, and the copy image is adjusted by adjusting the illumination distance of the zoom lens 45, and the magnification in the sub-scanning direction is adjusted by adjusting the sub-scanning speed of the optical scanning system. Adjust the magnification of the original image and copy image. A charger 48 is installed around the photosensitive drum 47.
, an eraser 49, a developing device 50, a transfer charger 51, a separation charger 52, a cleaning unit 53, etc. are provided in order of process. Two paper feeding systems are provided, and copy sheets are fed from one of the cassettes 54, 55 selected by paper feeding rollers 56, 57. Further, a double-sided tray 58 is provided, and when performing back-side copying, a copy sheet is supplied from the double-sided tray 58. 5
9 is a double-sided paper feed roller. Also, 60 is an operation board,
61 is a fixing section, 62 is a path switching mechanism, and 63 is a transport mechanism.

Next, an outline of the copy process will be explained. The photosensitive drum 47 rotates clockwise in FIG. 2, and its surface is uniformly charged to a predetermined high potential.

When the charged surface is irradiated with light from an optical scanning system, the potential changes depending on the intensity of the light. Since the light emitted by the optical scanning system corresponds to the original image, a potential distribution corresponding to the original image, that is, an electrostatic latent image, is formed on the surface of the photoreceptor drum 47. When the portion of the photoreceptor drum 47 on which the electrostatic latent image is formed passes through the developing device 50, toner is attracted to the photoreceptor drum 47 according to the potential distribution, thereby forming a toner image ( visible image) is formed. A copy sheet is fed at a predetermined timing from a selected sheet feeding system to the photosensitive drum 47 on which the visible image has been formed in this way, and is superimposed on the visible image. The visible image is then transferred to a copy sheet by the transfer charger 51. The copy sheet to which the visible image has been transferred is separated from the photosensitive drum 47 by the separation charger 52 and sent to the conveying section. The visible image is then fixed onto the copy sheet by a fixing section 61 provided in the conveyance section. In the case of single-sided copy mode, the copy sheet after fixing is transferred to the path switching mechanism 6.
2 and is immediately ejected in the direction of arrow A. However, when copying on the first side in double-sided copy mode, the conveyance direction of the copy sheet is reversed by the path switching mechanism 62, and the copy sheet passes through the conveyance mechanism 63. The images are stored in a double-sided tray 58.

An operation board 60 is arranged on the top surface of the copying machine. Further, an automatic document feeder (not shown) is installed above the contact glass 40 of this copying apparatus, and a sorter (not shown) is installed near the paper ejection port.

FIG. 3 shows the appearance of the operation board 60 of the copying machine. Referring to the figure, this operation board 60 includes a program key 70 for storing and recalling programs, a program display 71 for indicating that a program is in use, an interrupt key 72 for setting and canceling interrupt copy, and an interrupt key 72 for indicating interrupt copy status. Display 73, number confirmation key 74 used to confirm the number of sheets set during copying, variable size/programming, numeric keypad 75 used to set the number of copies, variable size, program setting, display panel 7 for displaying various information.
6. Double-sided key 77 for making double-sided copies, double-sided display 78 for displaying the status of double-sided copying, binding margin adjustment key 79 used to create a copy margin (margin), binding for displaying binding margin dimensions Alternative size display 80, DF mode key 81 used when unifying paper sizes or automatic paper selection
, Size uniformity display 8 showing the size uniformity state when using DF
2. Automatic paper selection display 83 that shows the automatic paper selection state when using a DF; Sort display 84 that shows the sorting state when using a sorter
, a stack display 85 showing the stack status when using the sorter;
Sorter key 86 used to set/cancel sorter mode and stack mode, ADF display 87 indicating ADFC (fully automatic) mode, 5 ADF display 88 indicating 5ADF (semi-automatic) mode, document feeder A
DF key 89 used when setting to either DF mode or 5ADF mode, original dimension manual display 90 that lights up when inputting the dimensions of the original, designated dimension manual display 91 that lights up when inputting the specified dimensions, copy Dimension magnification key 92 used when selecting magnification by dimension, copy magnification to 1
Dimension scaling key 93 used when selecting in % increments, page continuous copying display 94 to indicate page continuous copying status, page continuous copying key 95 used when automatically copying a double-page spread document one side at a time, original size and paper size The original size selection key 96 is used to determine the copy magnification, the reduction key 97 is used to make a reduced copy, the enlargement key 98 is used to make an enlarged copy, the same size key 99 is used to return to the same size copy, and the copy paper Paper selection key 100 for special use, shading adjustment key 1 used to adjust the shading of a copy image
01, an automatic density key 102 used to set and release the automatic density adjustment function, a clear stop key 103 used to change the number of sheets set, interrupt repeat copying, cancel program protection, etc., a start key 104 to start the copy operation, A preheating mode/mode clear key 105 used to return each mode to the standard mode or switching between the preheating state and the normal state, and a preheating display 106 indicating the preheating state are provided.

In the size uniformity mode, the copy magnification is automatically set according to the size of the original and paper (copy sheet) (for example, A4.85, etc.). In automatic paper selection mode, the paper source is automatically selected according to the original size and copy magnification. Binding margin adjustment is a function that shifts the correspondence between the position of the original image and the position on the copy sheet in the sub-scanning direction. In this example, the position deviation amount is -10° -5, 0, +5 and +10 (mm). Any of 5 levels can be specified. It is possible to perform the densification margin on the front and back sides of the copy sheet independently.

To set the dimension scaling mode, press the dimension scaling key 93, specify the copy dimensions using the numeric keypad 75, press the number confirmation key 74, and then press the - variable dimension scaling key 93. , specify the copy dimensions using the numeric keypad 75, and press °
Press the number confirmation key 74.

With this operation, the copy magnification is automatically set by calculating the original and copy dimensions. In this example, the copy density is adjusted in seven steps, and by pressing a key, the density can be adjusted in the darker or lighter direction one step at a time.

FIG. 4 shows a configuration diagram of the control circuit of this copying machine. As can be seen from the figure, in this example, (1) a CPU that controls the display on the operation board 2, manual key processing, the heater control unit 3, and the lamp control unit 4; (2) the scanner motor 5 of the optical system and the lens/ CPU 7 for controlling mirror stepping motor 6, (3) clutch solenoid control unit 8, relay control unit 9
, 0N10 F F of motor control unit 12, etc., input processing of various sensor units 10, high voltage power supply unit 11
Copying operations are controlled by three microcomputers: a main control CPU 3, and a main control CPU 3 that controls the sequence thereof.

Next, FIG. 1 shows a connection diagram of each microcomputer for realizing the present invention.

In this figure, only the signals related to the present invention are shown, and the others are omitted. 13.7.1 in this figure represents each CPU. In this example, 13 is a main control CPU, which controls the other CPUs 1 through a serial communication line.

T and D are signal lines for transmission data. R and D are signal lines for receiving data. SEL is a select signal and C
This is a signal for switching communication with PU7 or PU1. T8
The D, RXD, and SEL terminals constitute data communication means.

When 5EL=L, the CPUs 13 and 7 communicate, and when 5EL=H, the CPUs 3 and 1 communicate.

MB3773 is a power supply voltage monitoring IC (reset means 14) with a built-in watchdog timer, and is an IC that outputs a reset signal when there is no large CK input for a set time or more, or when the power supply voltage falls below a certain voltage. This reset output is connected to the glue set terminal of each CPU 13, 7.1.

7 is an optical control CPU, and T and D are transmission data signals, which are connected to R and D of the CPU 13 via a buffer. R and D are received data, which are also T and D of the CPU 13.
and are connected via a buffer. Reset input is C
This is the output signal of I CMB 3773 of PU13. ■
is the CPU for controlling the operation unit, and each signal is the CPU for optical control.
It is the same as PU7.

Next, the procedure of each CPU data communication will be explained with reference to FIG. The main control CPU 13 starts communication. First, the SEL signal is set to "H" and data is transmitted to the optical control CPU 7. Then, a reception interrupt INTSR is generated in the optical control CPU 7, and the reception data is fetched in the interrupt processing routine, and then the main control CPU 1
Send data to 3. Main control CPU13
When the data is received, a reception interrupt INTSR is generated, and in the same processing routine, the received data is taken in, the SEL signal is set to "L", and the data is transmitted to the CPU for controlling the operating section. Then, the CPU for controlling the operation unit
Then, a reception interrupt occurs, and data is transmitted to the main control CPU 13 as in the case of the optical control CPU 7. A reception interrupt occurs again in the main control CPU 13, and then the SEL signal is set to "H" and the optical control CPU
Send data to U7. From now on, repeat this constantly.

Next, a program for realizing the present invention will be explained based on a flowchart.

FIG. 6 shows the main routine of the main control CPU 13. After turning on the power, initialize the memory and peripheral controllers (1-1), then set the SEL signal to “H”.
” (1-2), and transmits data to the optical control CPU 7 (1-3).

After that, enable reception interrupts (1-4) and execute the main processing routine (copy sequence control, etc.) (1-5)
, and then repeat this.

FIG. 7 similarly shows the serial reception interrupt processing routine of the main control CPU 13. This routine is activated when data is received from the CPU 7 or 1 and reception interrupts are enabled. First, disable reception interrupts 2-1) and perform reception processing <2-
2). Next, determine whether the SEL signal is “H” or “L”.
-3), “H” to “L” (2-4), “L”
In this case, the data is set to H'' (2-5), data is transmitted to the CPU 7 or 1 (2-6, 2-7), and the process returns.

FIG. 8 shows the main routine of the optical control CPU 7. First, the main control CPU 13 is initialized (3-1) in the same way as the main control CPU 13, and then reception interrupts are enabled (3-2) while the optical system processing routine is executed (3-1).
3) Waiting for reception interrupt. When an interrupt occurs, the processing routine shown in FIG.
4-3) Return to send data to U13.

The communication procedure is the same in the case of the CPU for controlling the operation unit, so the description thereof will be omitted.

By performing the above operations, all CPUs can be reset and restarted if any of the CPUs malfunctions. Furthermore, by adding a latch means to the reset output, the reset state can be maintained and the copying operation can be prohibited.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to easily and accurately detect abnormalities in a copying apparatus, and prevent failures or disasters due to malfunctions.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the connection relationship between CPUs, which are the main parts of the present invention, FIG. 2 is an internal mechanism diagram of a copying machine according to an embodiment of the present invention, and FIG. 3 is a plan view of its operation board. FIG. 4 is a control block diagram of the copying machine, FIG. 5 is an explanatory diagram explaining the procedure of data communication between CPUs, FIGS. 6, 7, 8,
FIG. 9 is a flowchart of the main routine and interrupt routine related to the control of the present invention. 1.7.13...CPU, 14...Reset means,
"rx D, R collar, S, EL...Data communication means. Figure 1 Figure 5 Figure 4 Figure 6 Figure 8 Figure 9

Claims (1)

[Claims] In a copying machine that has a plurality of CPUs that manage preset control and a data communication means between the respective CPUs, during normal program operation, a clearing clock signal is received from the communication means, and on the other hand, the communication 1. A copying apparatus comprising a reset means for detecting an abnormality and resetting the CPU when a clock signal is not outputted from the communication means for a predetermined time set longer than an interval time.