JPH0782585B2 - Light emitting device operation diagnostic device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting element operation diagnosis apparatus which is preferably implemented in a copying machine or the like.

BACKGROUND ART Conventionally, copying machines have been provided with a reduction key and a display lamp in order to copy not only the original image but also the original image. When performing reduction copying, the reduction key is operated, whereby the display lamp lights up and the reduction copying mode is displayed.

Problems to be Solved by the Invention In the above-mentioned prior art, when the display lamp remains turned off due to some trouble, the display state indicates that the copying operation is performed at the same magnification. Therefore, the operator thinks that the same size copying will be performed, and when the copying operation is performed, the reduced copying paper is obtained.
Moreover, when the number of set sheets is large, useless copying and useless time are spent.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above technical problems and to provide a light emitting element operation diagnosing device having a simple structure and capable of reliably identifying an abnormal operation of a light emitting diode.

Means for Solving the Problems The present invention includes (a) an impedance element, a light emitting element connected in series with the impedance element, and a switching element connected in series with the light emitting element for turning on or off the light emitting element. A light emitting element drive circuit for forming a light emitting element drive circuit by: (b) means for giving a control signal to the switching element to turn on or off the light emitting element as necessary, and (c) the light emitting element Means for outputting an operation signal indicating an operating state of extinction or light emission of the light emitting element at a connection point with the impedance element; and (d) a control signal for conducting the switching element,
A state of combination with an operation signal from the output means corresponding to lighting or extinguishing operation of the light emitting element at this time, a control signal for shutting off the switching element, and extinguishing or lighting operation of the light emitting element at this time And a means for discriminating whether an abnormal or normal operation has occurred based on a combination state with the operation signal of the output means corresponding to the above.

Embodiment FIG. 1 is an electric circuit diagram showing the configuration of an embodiment of the present invention. Copying mechanism 1 for performing the same-size and reduced-size copying operations
The number of copies is set by the ten keys 3 of the operation panel 2 whose plane is shown in FIG. The copy density is adjusted with the density adjustment key 4. Each time the reduction key 5 is pressed, the reduction mode and the normal size mode are switched. In the reduction mode, the indicator lamp 6 is lit,
The display lamp 6 is turned off in the normal size mode. When the print button 7 is operated at the start of copying, the power-on display lamp 8 is turned on and the number of copies is displayed on the display means 9.

Corresponding to the operation of the ten-key pad 3, the density adjustment key 4, the print button 7 and the reduction key 5, the control operation of the copying mechanism 1 is controlled by the processing circuit 10 realized by a microcomputer or the like.

In the processing circuit 10, when the reduction key 5 is operated and the copying operation is to be performed by the copying mechanism 1, a high level signal is output to the line 15. The line 15 is connected to the base of a transistor 16 as a switching element. A resistor 17, a reduction operation light emitting diode 6, and a transistor 16 are connected in series between the high potential side line 12 of the power source + V1 and the low potential side ground line 13. Processing circuit 10 to line 15
When a high-level signal is applied via the transistor 16, the transistor 16 becomes conductive and a current flows through the light emitting diode 6 to turn it on.

Next, when the reduction key 5 is pressed to perform the same size copying, a low level signal is given to the line 15, the transistor 16 is cut off, and the light emitting diode 6 is turned off.

The connection point 18 between the light emitting diode 6 and the resistor 17 is a comparison circuit 19
One of the input terminals 20 is connected. The reference voltage divided by the resistors 22 and 23 is applied to the other input terminal 21 of the comparison circuit 19. The comparator circuit 19 derives a high level signal when the voltage of the input terminal 20 is lower than the reference voltage of the input terminal 21, and derives a low level signal when the voltage of the input terminal 20 is equal to or higher than the reference voltage of the input terminal 21. To do. The signals from these comparison circuits 19 are input to the processing circuit 10 via the signal line 24.

At the time of reduction copying, when the signal applied via the line 15 is at a high level, the transistor 16 becomes conductive as described above, and the voltage at the input terminal 20 is lower than the reference voltage at the input terminal 21 due to the connection point 18. Therefore, the comparison circuit
The output of 19 becomes high level.

At the time of copying at the same size, the signal given through the line 15 is at a low level, the transistor 16 is cut off, the connection point 18 makes the input terminal 20 at a high level, and is higher than the reference level of the input terminal 21. The output of 19 becomes low level.

In this way, when the light emitting diode 6 is performing the normal display operation, the determination result shown in Table 1 is obtained.

When the transistor 16 is short-circuited and remains conductive due to the failure of the transistor 16, the light-emitting diode 6 remains lit regardless of whether the signal on the line 15 according to the input operation of the reduction key 5 is high level or low level. Is. When the reduction key 5 is operated and the signal on the line 15 is at the high level corresponding to the reduction operation, the signal on the line 24 is at the high level as described above, and the processing circuit 10 determines that the signal is normal. When the reduction key 5 is operated to copy at the same size, the signal on the line 15 is at the low level, but the transistor 16
Is short-circuited, the light-emitting diode 6 is on, the voltage at the connection point 18 is low, and the output of the comparison circuit 19 is at a high level. The processing circuit 10 determines that the display state of the light emitting diode 6 is abnormal according to the combination of the low level signal derived via the line 15 and the high level signal output via the line 24. judge. At this time, the processing circuit 10 controls the copying mechanism 1 so as to achieve the same size copying that should be performed when the light emitting diode 6 is off regardless of the operation of the reduction key 5.

When the light emitting diode 6 is normal, the operation as shown is performed by the copying mechanism 1.

Next, the operating state of the above-mentioned diagnostic device will be described below by using the flow chart shown in FIG. The process moves from step n1 to step n2 and the reduction key 5 is pressed to read the input display. Then, the processing circuit 10 is moved to step n3.
From the transistor 16 to the control signal, step n4
Then, the output signal from the comparison circuit 19 is read and step n5
It is determined whether or not it is normal. If it is normal in step n5, the copying operation corresponding to the input content of the reduction key 5 is performed by the copying mechanism 1 in step n6. If it is not normal in step n5, the process moves to step n7 to perform a copying operation corresponding to the display state of the light emitting diode 6, that is, a copying mechanism so that reduction copying can be achieved when the light emitting diode 6 is off in the reduction mode. 1 is controlled, or the copying mechanism 1 is controlled so that 1 × copying can be achieved when the light emitting diode 6 is turned on in the 1 × mode.

In the above embodiment, the copying operation corresponding to the display state of the light emitting diode 6 is performed at the time of abnormality,
For example, an abnormal state may be notified by an alarm sound.

FIG. 4 is an electric circuit diagram showing the configuration of another embodiment of the present invention, and FIG. 5 is a plan view of the operation panel 30. This embodiment is similar to the previous embodiment, and corresponding parts bear the same reference numerals. Note that the operation panel 30 has a sort key
31 is provided, and when the sort key 31 is pressed, the display lamp 32 lights up to enter the sort mode. When the sort key 31 is pressed further, the display lamp 32 is turned off and the sort mode is switched to the non-sort mode. A series circuit of a resistor 17a, a light emitting diode 32 and a transistor 16a is connected in parallel to the high potential side line 40 and the ground side line 41. Also, the connection point 4 between the line 40 and the resistor 17a
2 and a connection point 43 between the line 41 and the transistor 16a are connected in parallel with a series circuit of resistors 17b and 17c. The connection point 44 between the resistor 17a and the light emitting diode 32 and the resistor 17b, 1
The diode D1 is interposed between the connection point 45 and the connection point 45 between 7c.
The cathode side of the diode D1 is connected to the connection point 44, and the anode side is connected to the connection point 45. Also resistance
Another diode D2 is interposed between the connection point 18 between 17 and the light emitting diode 6 and the connection point 47 between the connection point 45 and the resistor 17c. The cathode side of this diode D2 is connected to the connection point 18, and the anode side is connected to the connection point 47.
Connected to.

With such a configuration, when at least one of the light emitting diodes 6 and 32 is turned on, the output from the comparison circuit 19 becomes high level, and it is not possible to specify which light emitting diode is abnormal, but the sixth By deriving signals having different periods as shown in FIGS. 1A and 1B from the processing circuit 10, the determination result as shown in Table 2 can be obtained. Therefore, one comparator circuit 19 detects whether or not the operations of the plurality of light emitting diodes 6, 32 are normal, so that the circuit configuration can be simplified.

FIG. 7 is an electric circuit diagram of still another embodiment of the present invention. A light emitting diode 72 and a resistor 73 are connected in series to a transistor 71 as a switching element, and a power supply voltage + V2 is applied. Processing circuit 74 to transistor
Control signals are provided to the base of 71 via line 75. The light from the light emitting diode 72 is received by the phototransistor 76 as a light receiving element. Light emitting diode 72
And the phototransistor 76 constitute a photocoupler 77. A resistor 78 is connected in series to the phototransistor 76,
Power supply voltage + V3 is applied. Resistor 78 and phototransistor
A line 79 is connected to a connection point with 76, and an output corresponding to the light receiving state of the phototransistor 76 is derived.

By using such a photocoupler 77, a signal is transmitted and received even when the power supply voltage + V2 of the transistor 71 and its related circuit and the power supply voltage + V3 of the phototransistor 76 and its related circuit are different. Is possible.

When the line 80 between the photocoupler 77 and thus the light emitting diode 72 and the transistor 71 extends relatively long, for example over many meters, the light emitting diode 72
It becomes necessary to judge whether or not the robot is operating accurately. For this purpose, the connection point between the light emitting diode 72 and the resistor 73 is connected to the processing circuit 74 via the line 81. When the control signal sent through the line 75 is at the low level, the transistor 71 is cut off, so that the light emitting diode 72 is turned off, and the high level signal is sent to the processing circuit 74 through the line 81. Given. When the control signal sent through the line 75 is at high level, the transistor 71 is turned on and the light emitting diode 72 is turned on.
A low level signal is supplied from 81 to the processing circuit 74.

When the combination of the logical states of the input from the line 75 and the output from the line 81 is similar to that described above, the processing circuit 74 determines that the light emitting diode 72 is operating normally.

When transistor 71 is not conducting due to a fault, light emitting diode 72 remains illuminated, which causes the control signal provided via line 75 to go high from line 81 despite being low. The level signal is sent to the processing circuit 74. Such a combination of the logical states of the input signal provided through the line 75 and the output signal provided through the line 81 is detected by the processing circuit 74 and is determined to be abnormal.

When the transistor 71 and the light emitting diode 72 are disconnected, the light emitting diode 72 remains off, and even if a high level signal is given from the line 75, the signal sent through the line 81 remains high. It remains at the level. Such a combination of the logic states of the input signal provided through the line 75 and the output signal provided through the line 81 is judged to be abnormal by the processing circuit 74.

In this way, the processing circuit 74 determines the logical state of the input signal applied via the line 75 and the output signal transmitted via the line 81 to identify the occurrence of the abnormal condition. Yotsutte transistor 71 and light emitting diode 72
You can immediately know the failure.

FIG. 8 is an electric circuit diagram of another embodiment of the present invention. The transistor 91 as a switching element, the light emitting diode 92 and the resistor 93 are connected in series, and the power supply voltage + V4
Is applied. A control signal is applied to the transistor 91 from the processing circuit 94 via the line 95. Light emitting diode 92
Light from is received by the phototriac 96. The photo triac 96 is connected in series with the resistors 97 and 98, and is also connected to the gate electrode of the triac 99. The triac 99 is connected to the AC power supply 100 and the load 101, and the conduction angle control is performed. A capacitor 102 is connected in connection with the triac 99.

In order to identify whether the light emitting diode 92 is operating normally, the connection point between the light emitting diode 92 and the resistor 93 is connected to the processing circuit via the line 103. When a high level signal is applied to the base of the transistor 91 via the line 95, the light emitting diode 92 is turned on, and at this time, a low level signal is sent to the processing circuit 94 via the line 103. When the control signal provided via line 95 is at low level, light emitting diode 92 remains off, and therefore the output from line 103 is at high level. The processing circuit 94 receives the input signal from the line 95 and the line 103.
It is determined that the light emitting diode 92 is operating normally by determining the combination of the logic state of the light emitting diode 92 and the output signal from the light emitting diode 92.

When the transistor 91 has failed and the light emitting diode 92 remains lit, the output signal from the line 103 is low level even though the input signal from the line 95 is low level. Based on the combination of the above, the processing circuit 94 identifies that the light emitting diode 92 is malfunctioning. When the transistor 91 and the light emitting diode 92 are disconnected, even if the input signal from the line 95 is at the high level, the output signal from the line 103 remains at the high level, and the processing circuit 94 is the same as described above. It is identified that the light emitting diode 92 is abnormally operating.

Although a transistor is used as the switching element in the above embodiment, it goes without saying that a relay switch may be used.

Effects As described above, according to the present invention, it is possible to reliably identify an abnormal operation of a light emitting diode with a simple configuration. In particular, according to the present invention, in order to diagnose the operating state of light emission and extinction of a light emitting element that malfunctions including a switching element connected in series to the light emitting element, control for actually turning off or turning on the light emitting element is controlled. Abnormality or normality can be identified based on the combination of the signal and the operation signal indicating the operation state of extinguishing or emitting light when the light emitting element is driven, and for example, it is turned on when the extinction state is commanded. It also becomes possible to perform abnormality diagnosis of the light emitting element.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of an embodiment of the present invention, and FIG.
FIG. 3 is a front view of the operation panel according to the illustrated embodiment, FIG. 3 is a flow chart showing an abnormal state identifying operation, FIG. 4 is an electric circuit diagram of another embodiment of the present invention, and FIG. FIG. 6 is a front view of an operation panel according to an example, FIG. 6 is a waveform diagram of a control signal from a processing circuit, FIG. 7 is an electric circuit diagram of still another embodiment of the present invention, and FIG. 8 is another embodiment of the present invention. It is an electric circuit diagram of. 1 ... Copier mechanism, 6,32,72,92 ... Light emitting diode, 16,1
6a, 71,76,91 …… transistor, 17,73,93 …… resistor, 10,
74,94 …… Processing circuit

Claims (1)

[Claims] 1. A drive circuit for a light emitting element, comprising: (a) an impedance element, a light emitting element connected in series with the impedance element, and a switching element connected in series with the light emitting element for turning on or off the light emitting element. A light emitting element drive circuit for forming the light emitting element, (b) means for giving a control signal to the switching element to turn on or off the light emitting element as necessary, and (c) a connection point between the light emitting element and the impedance element Means for outputting an operation signal indicating a light-off or light-emission operation state of the light-emitting element, and (d) a control signal for conducting the switching element,
A state of combination with an operation signal from the output means corresponding to lighting or extinguishing operation of the light emitting element at this time, a control signal for shutting off the switching element, and extinguishing or lighting operation of the light emitting element at this time And a means for identifying whether an abnormal or normal operation is occurring based on a combination state with the operation signal of the output means corresponding to the above.