JPH032783B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detection device for detecting the size of a paper cassette installed in a copying machine.

Conventionally, as this type of detection device, those shown in FIGS. 1 to 3 are known. Copy machine body a
In the vicinity of the cassette insertion port b, there are three micro-switches C ₁ to
C ₃ is installed. On the other hand, a projection e is provided on one side of the paper cassette d for pressing the contacts of the microswitches C ₁ to _{C 3} to selectively switch them. In this case, the protrusion e is arranged at a position that changes depending on the cassette size. For example, for an A4 size cassette d, as shown in Fig. 1, the protrusion e is placed at a position opposite the micro switch _C1 , , B4 size cassette d', the protrusion e' is provided at a position opposite to the micro switch _C2 , as shown in FIG. Therefore, when the micro switches C ₁ to C ₃ are selectively switched, the corresponding one of the size display lamps f ₁ to _{f 3} of the display f shown in FIG. 3 lights up. ing. In addition, the display lamps f ₁ to _{f 3}
is assigned to a cassette size, for example, A ₄ , B ₄ , or B ₅ size, and its lighting indicates the cassette size.

However, this type of device requires at least three microswitches to detect three types of cassette sizes, which increases the mounting space, complicates the switch wiring, and increases the assembly process. This may lead to increased costs.

This invention was made against the background of the above-mentioned circumstances, and its purpose is to reduce mounting space, the number of wiring lines, and assembly man-hours, and to detect the cassette size reliably and effectively. An object of the present invention is to provide a cassette size detection device for a copying machine.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 4 to 6. 1 in Fig. 5 is the main body of the copying machine in which the cassette insertion port 2 is formed;
A pair of electrodes 3, 3 are arranged in the inner part of the insertion port 2. The electrodes 3, 3 are formed in a flat plate shape, and are arranged so that the plate surfaces are perpendicular to the direction of entry into the cassette. The electrodes 3, 3 are always urged toward the opening of the insertion port 2 by the elastic force of the coil springs 4, 4. Furthermore, the electrodes 3, 3 are connected to lead wires 5, 5.
They are electrically connected to input terminals C _A and C _B of the circuit shown in FIG.

On the other hand, on one side of the paper cassette 6, an electrode 3,
electrodes 7, 7 with a spacing corresponding to the spacing of 3
are disposed therein, and electrodes 7,
A resistor R _A connected between 7 and 7 is disposed. The resistance value of this resistor R _A varies depending on the cassette size, for example, it is 1 kΩ for an A4 size cassette, and 5 kΩ for a B4 size cassette.

Next, the circuit shown in FIG. 4 will be explained. The output voltage of the power supply battery E is supplied as the operating voltage of the comparator circuit 8, and is also supplied as the operating _voltage of the control circuit 9.
Each is supplied to the GND input terminal. and,
The positive electrode side of the battery E is connected to one end of the resistor R _B , and the negative electrode side thereof is connected to one end of the resistor R _A on the cassette 6 side when the cassette 6 is attached to the main body 1 of the copying machine. The other ends of the resistors R _A and R _B are connected to each other, and the divided voltage by the resistors R _A and R _B is applied to one input terminal of the comparator circuit _{8 .}
It is supplied from the connection point as the compared voltage V(-).

The control circuit 9 controls various operations, and has a storage section for storing microinstructions, an arithmetic/judgment section, etc., and receives various control signals O ₁ -
Output O _N , P ₁ to P _N . The control signals O ₁ to O _N are signals that are supplied to the corresponding resistors R ₁ to _RN and sequentially select the resistors R ₁ to _RN according to their output states.
The other ends of the resistors R ₁ to R _N are connected to the positive electrode side of the battery E via the resistor R _C , and the resistor is connected to the + input terminal of the comparator circuit 8.
A voltage divided by a resistor selected from R ₁ to _RN and a resistor _RC is supplied as a reference voltage V(+) from a connection point between the resistors R ₁ to _RN and the resistor _RC .

The comparator circuit 8 has input voltages V(-) and V(+) of V
Outputs a comparison result signal that is a low level binary logic level when (-)>V(+) and a high level when V(-)<V(+), and inputs the signal to the control circuit 9.
It is now given as I _A. Note that R _L is a resistor connected between the output side of the comparator circuit 8 and the positive electrode side of the battery E.

The control signals P ₁ to P _N output from the control circuit 9 are
Compatible LED (light emitting diode) driver 10-
These signals are applied to signals 1 to 10-N and output drive signals, respectively. LED driver 10-1 to 10
-N is constituted by an inverter, and its output is connected to the negative electrode side of the corresponding LEDs 11-1 to 11-N. The positive electrode sides of the LEDs 11-1 to 11-N are connected to the positive electrode side of the battery E via a resistor _RF .

Next, the operation of the cassette size detection device constructed as described above will be explained with reference to the flowchart shown in FIG. Now, the resistance R _A on the cassette 6 side is
Depending on the size of the cassette 6, one input voltage V(-) of the comparator circuit 8 V(-) = R _A /R _A +R _B ×E is set to A4 when the output voltage of the battery E is 10V
2V for size, 4V for A3 size, 6V for B5 size,
It is assumed that the B4 size is set to 8V. Moreover, the resistors R _C and R ₁ to _{R 4} are connected to the comparator circuit 8.
The other input voltage V(+) of battery E is
When the voltage is 10V, V(+)=R ₁ /R ₁ +R _C ×E=3V V(+)=R ₂ /R ₂ +R _C ×E=5V V(+)=R ₃ /R ₃ +R _C It is assumed that the settings are as follows: ×E=7V V(+)=R ₄ /R ₄ +R _C ×E=9V.

First, in step _S1 , the control circuit 9 receives a control signal.
Out of O ₁ to O _N , only the control signal O ₁ is set to Low level. As a result, a current flows through the resistor R ₁ , and the + input terminal of the comparator circuit 8 receives the resistors R ₁ ,
A divided voltage by R _C , that is, V(+)=R ₁ /R ₁ +R _C ×E=3V, is applied. next step
_S2 determines whether the signal I _A input to the control circuit 9, that is, the comparison result signal of the comparator circuit 8, is at High level. In other words, the input voltages V(-), V( +) is determined to be V(-)<V(+). Now, if it is determined that the signal I _A is at High level and the voltage V (-) < V (+),
The resistance R _A applied to the − input terminal of the comparator circuit 8,
Since the divided voltage V(-)=R _A /R _A +R _B ×E due to R B is smaller than the voltage V (+)=3V, the installed cassette ₆ has a voltage V(-)=2V A4 It is determined that it is a cassette of the same size, and the process moves to the next step _S3 . In this step _S3 , the control circuit 9 executes a process of setting only the control signal _P1 among the control signals _P1 to _PN to a high level. As a result, an inverted signal of the signal _P1 is applied from the LED driver 10-1, so in the next step _S4 , the LED driver 10-1
1-1 is turned on, and it is clearly shown that the A4 size cassette 6 has been loaded.

Furthermore, if it is determined in step _S2 that the signal _IA is not at a high level, the process proceeds to the next step _S5 . In this step _S5 , the control circuit 9 outputs the control signal
Execute processing to return O ₁ to High impedance.
Subsequently, in the next step _S6 , the control circuit 9 executes a process of setting the control signal _O2 to a low level.
This causes current to flow through resistor R ₂ and comparator circuit 8
The + input terminal of the + input terminal has a voltage divided by resistors R ₂ and _R
That is, V(+)=R ₂ /R ₂ +R _C ×E=5V is applied. Then, in the next step _S7 , it is determined whether the signal _IA is at the High level.
If it is determined that the signal IA is now at the High level, the voltage V(-) is 3V<voltage V(-)<5V, so the mounting cassette 6 is set to the voltage V(-).
It is determined that it is an A3 size cassette with (-) = 4V, and steps corresponding to steps S ₃ and S ₄ described above are executed.
Execute S ₈ and S ₉ sequentially. By executing steps _S8 and _S9 , the LED 11-2 is turned on, clearly indicating that the A3 size cassette 6 has been loaded.

Furthermore, if it is determined in step _S7 that the signal _IA is not at the High level, the step S7 described above is performed.
Steps S ₁₀ and S ₁₁ corresponding to S ₅ and S ₆ are sequentially executed. As a result, current flows through the resistor R ₃ and the voltage divided by the resistors R ₃ and R _C is applied to the + input terminal of the comparator circuit 8, that is, V(+) = R ₃ /R ₃ +R _C ×E = 7V. It will be applied. And the next step
In S ₁₂ , the same process as in step S ₂ or S ₇ described above is executed, and the step is changed according to the judgment result.
S ₁₃ , S ₁₄ or S ₁₅ , S ₁₆ are executed. Steps S ₁₃ and S ₁₄ execute processes corresponding to steps S ₃ and S ₄ described above, and when these steps S ₁₃ and S ₁₄ are executed, voltage V(-) is 5V<voltage (-)<7V, the installed cassette 6 has a voltage of V
Since it is a B5 size cassette with (-)=6V, the LED 11-3 is turned on, clearly indicating that the B5 size cassette 6 is installed. Also,
_Steps S ₁₅ and S ₁₆ execute processes corresponding to steps S ₅ and S ₆ described above.
By executing _S16 , a current flows through the resistor _R4 , and the + input terminal of the comparator circuit 8 receives the voltage divided by the resistors _R4 and R _C , that is, V(+) = _R4 / _R4 + R _C × E=9V is now applied. And the next step
In _S17 , the same process as in step _S2 described above is executed, and it is detected whether or not a cassette of B4 size, which is the next size, has been loaded.

Hereinafter, in the same way as described above, the processing corresponding to any N size cassette from a B4 size cassette is as follows.
Steps _S18 to _S23 are executed sequentially. In this case, steps S ₁₈ , S ₁₉ or S ₂₃ , S ₂₄ correspond to steps S ₃ , S ₄ described above, and steps S ₂₀ to S ₂₂ , S ₂₅ correspond to steps S ₅ , S 25 described above. ₆ ,
This is a process corresponding to _S7 .

In this way, the control circuit 9 sequentially and selectively designates the control signals O ₁ to O _N to vary the magnitude of the reference voltage applied to the comparator circuit 8, so that the comparison result signal of the comparator circuit 8 is Cassette size A4, A3, depending on
LED11-1 to 11-5 corresponding to B5, B4, A5
Since it is made to light up, it is possible to detect many types of cassette sizes with one comparison circuit 8. By changing the resistance R _A on the cassette 6 side according to the cassette size, the LEDs 11-1 to 11-1 corresponding to the cassette size are set.
5 is selectively illuminated, the detection can be performed reliably and satisfactorily.

Note that this invention is not limited to the above embodiments,
Various modifications can be made without departing from the scope of the present invention, and for example, the present invention is not limited to LEDs, and may be applied to liquid crystal display devices.

As explained in detail above, according to the cassette size detection device according to the present invention, a resistive element disposed on the cassette side is connected to one input terminal of the comparator circuit, and a plurality of resistive elements are connected to the other input terminal. The cassette is equipped with a control circuit that connects a plurality of resistor elements and sequentially selects and specifies the reference voltage supplied to the comparator circuit, and also detects the comparison result signal from the comparator circuit. By varying the resistance value of the side resistor element depending on the cassette size, for example, it is possible to detect a plurality of types of cassette sizes even with a single comparison circuit. In addition, since there is no need for a large number of microswitches as in the past, it is possible to reduce the mounting space, number of wires, and assembly process.
Cost reduction can be achieved.

[Brief explanation of the drawing]

1 to 3 show a conventional cassette size detection device, FIG. 1 is a schematic configuration diagram, FIG. 2 is a diagram showing a cassette of another size different from that in FIG. 1, and FIG. 3 is a circuit diagram. The configuration diagrams, FIGS. 4 to 6 show an embodiment of the present invention, and FIG. 4 is a circuit configuration diagram,
FIG. 5 is a schematic configuration diagram, and FIG. 6 is a flowchart showing the operation. DESCRIPTION OF SYMBOLS 1... Copying machine main body, 6... Cassette, 8... Comparison circuit, 9... Control circuit, 11-1 to 11-N...
…LED.

Claims (1)

[Claims] 1. A comparator circuit whose one input terminal is connected to a reference voltage source, and a resistor for generating a voltage to be compared, which is disposed on the cassette side and is connected to the other input terminal of the comparator circuit when the cassette is installed. 1. A cassette size detection device comprising: a cassette size detection device; and a display device that indicates the size of a loaded cassette in response to the output of the comparison circuit.