JPH032784B2 - - 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 C1 to C1 with switch contacts facing into the insertion port b.
C3 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 C1 to C3 to selectively switch them. In this case, the position of the protrusion e is changed depending on the cassette size. For example, if the cassette d is A4 size, as shown in FIG.
In the case of a B4 size cassette d', the protrusion e' is provided at a position opposite to the micro switch C2, as shown in FIG. Then,
When the microswitches C1 to C3 are selectively switched, the corresponding one of the size display lamps f1 to f3 of the display f shown in FIG. 3 lights up. Note that the display lamps f1 to f3 correspond to the cassette size, for example, A ₄ , B ₄ ,
It corresponds to the _B5 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 will lead to an increase in 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 efficiently. 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. 4 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. This resistor R _A has a resistance value that differs 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. 5 will be explained. The output voltage of the battery E, which is a reference voltage source, is controlled by the control circuit 8.
are supplied to the V _DD and V _SS input terminals, respectively.
A resistor is connected in series between the two poles of battery E.
R ₁ and R ₂ are connected. This resistance R ₁ , R ₂
The connection point is connected to the +input terminal of the comparator circuit 9, and the voltage divided by the resistors R ₁ and R ₂ is supplied as a reference voltage to the comparator circuit 9. Further, the positive electrode side of the battery E is connected to the emitter side of the transistor _TR . This transistor T _R is a PNP type transistor, and there is a resistor R ₃ between its emitter and base.
is connected to it, and a control circuit 8 is connected to its base.
The signal _OA output from the circuit is supplied via the resistor _R4 . Also, the transistor T _R
The collector side of is connected to the − of comparator circuit 9 via resistor _R5 .
connected to the input terminal. A capacitor C is connected between the − input terminal of the comparator circuit 9 and the negative electrode side of the battery E.
is connected. This capacitor C is connected in parallel with a resistor R _A on the cassette 6 side when the cassette 6 is installed in the copying machine main body 1. Note that a resistor R ₆ is connected between the output side of the comparison circuit 9 and the positive electrode side of the battery E.

The control circuit 8 controls various operations.
In addition to having a ROM (read-on memory) that stores micro instructions, etc., arithmetic/judgment section, etc.
The configuration includes a counter that counts the discharge time of capacitor C based on a predetermined clock signal.
It is designed to output O _A , O ₁ to _{O N} . the above
The ROM stores in advance numerical data corresponding to a plurality of cassette sizes, for example A4, A3, B5, B4, and A5 sizes. Note that the numerical data is compared data that is compared with the numerical data counted by the counter.

The comparator circuit 9 compares the voltage V(-) supplied to its - input terminal and the voltage V(+) supplied to its + input terminal, and as a result, V(-)>V(+).
When , the low level of the binary logic level, V
When (-)<V(+), a comparison result signal having a High level is outputted, and is supplied to the control comparison 8 as an input signal _IA .

The control signals O ₁ to O _N output from the control circuit 8 are as follows:
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 applied 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, assume that the numerical data corresponding to the cassette sizes stored in the ROM of the control circuit 8 corresponds to A4 size, A3 size, B4 size, B5 size, and A5 size. in this case,
Each numerical data is A4>A3>B4>B5>A5.

First, in step _S1 , the control circuit 8 receives the signal
Executes processing to set O _A to Low level. As a result, transistor _TR is turned on.
When transistor _TR is turned on, the next step _S2
is executed, and capacitor C is rapidly charged with the output voltage of battery E through resistor _R5 . and,
In the next step _S3 , the comparison result input voltage of the comparator circuit 9 becomes V(-)V(+), and the control circuit 8
A low level signal _IA is input. In this case, the resistors R ₁ and R ₂ that determine the reference voltage of the comparator circuit 9 can have arbitrary values, but are preferably set so that the voltage V(+) to the comparator circuit 9 is about 1/2E. .
Therefore, in the state of step _S3 above, the capacitor C
In other words, until the voltage across E _C becomes stable, E _C
It is maintained until =0. And the next step
Moving on to the execution of _S4 , the control circuit 8 executes the process of setting the signal _OA to the High level. As a result, transistor _TR is turned off. As a result,
The next step _S5 is executed, and the charge in the capacitor C gradually starts discharging via the resistor R _A on the cassette 6 side. As a result, the voltage E _C across the capacitor C gradually decreases. Then, proceeding to the next step _S6 , the control circuit 8 starts the counting operation of the counter provided therein. Therefore, when the potential E _C decreases due to the discharge of the capacitor C, the comparison result in the comparator circuit 9 becomes V(-)<V
(+) is determined in accordance with the signal _IA input to the control circuit 8 in step _S7 , and waits until V(-)<V(+).
When V(-)<V(+), the High level signal _IA is input from the comparison circuit 9 to the control circuit 8 in the next step _S8 . This allows the step
_S9 is executed and the counting operation of the counter in the control circuit 8 is stopped. Therefore, the count data of the counter corresponds to the discharge time of the capacitor C.

Therefore, in the next step _S10 , the control circuit 8 is
A4 data, which is cassette size data, is read from the ROM and compared with the count value data of the counter, and it is determined whether the A4 data is larger than the contents of this counter. If it is determined that A4 data > counter contents, it is determined that the installed cassette 6 is A4 size, and the next step is performed.
Moving on to the execution of _S11 , the control circuit 8 executes a process of setting only the signal _O1 among the signals _O1 to _ON to the Hight level. As a result, the LED driver 10-1 outputs an inverted signal of the signal _O1 , so in the next step _S12 , the LED 11-1 is turned on, clearly indicating that the A4 size cassette 6 has been loaded. .

In addition, if it is determined in step _S10 that A4 size is not larger than the contents of the counter, proceed to the next step.
Moving on to the execution of _S13 , the cassette size A3 data is read from the ROM of the control circuit 8 and compared with the counted value data of the counter, and it is determined whether or not the A3 data is larger than the contents of this counter. now,
If it is determined that A3 data>counter contents, it is determined that the installed cassette 6 is A3 size, and steps _S14 and _S15 corresponding to the above-mentioned steps _S11 and _S12 are sequentially executed. This step S ₁₄ ,
By executing S ₁₅ , LED11-2 is turned on and A3
It is clearly shown that the large size cassette 6 has been installed.

Thereafter, similar processing is sequentially executed in steps _S16 to _S24 . That is, step S ₁₆ ,
In S ₁₉ and S ₂₂ , the cassette-sized B5 data, B4 data, and A5 data are sequentially read from the ROM of the control circuit 8 and compared with the counted value data of the counter, and as a result, it is determined that the B5 data is larger. Steps S ₁₇ , S ₁₈ , B4 If it is determined that the data is large, steps S ₂₀ , S ₂₁ , A5
If the data is judged to be large, the step
S ₂₃ and S ₂₄ are executed, and the corresponding LED11-
3, 11-4, and 11-N are turned ON, and it is clearly shown that the installed cassette 6 is B5 size, B4 size, or A5 size.

In this way, the control circuit 8 counts the discharge time of the capacitor C until the output signal of the comparator circuit 9 is generated, and compares this counted value data with the numerical data of the cassette size stored in the ROM in advance. , the cassette size is detected according to the comparison result. Therefore, by changing the value of the resistor R _A on the cassette 6 side depending on the cassette size, it is possible to detect many types of cassette sizes with one comparison circuit 9, and also to detect the LED 11 according to the cassette size. -1 to 11-N can be selectively turned on.

Note that the present invention is not limited to the above-mentioned embodiments, and can be modified and applied in various ways without departing from the scope of the present invention. For example, the present invention is not limited to LEDs, and may be applied to liquid crystal display devices. Further, although this embodiment has been described using the discharging characteristics of the capacitor and the resistor, it is also possible to connect the capacitor and the resistor in series to utilize the charging characteristics.

As explained in detail above, according to the cassette size detection device according to the present invention, a reference voltage source is connected to one input terminal of the comparator circuit, a capacitor is connected to the other input terminal, and a capacitor is connected to the cassette side. When the cassette is installed in the copying machine, the resistor element provided is connected in parallel to the capacitor, and the discharge time of the capacitor is counted until the output signal of the comparator circuit is generated, and the cassette is connected according to this counted value. Since the size is displayed,
By changing the resistance value of the resistance element on the cassette side depending on the cassette size, it is possible to detect multiple types of cassette sizes even with a single comparator circuit, and it is also possible to detect multiple types of cassette sizes, for example, with a single comparator circuit. Since no microswitch is required, it is possible to reduce the mounting space, the number of wires, and the assembly process, thereby reducing costs.

[Brief explanation of the drawing]

1 to 3 show a conventional cassette size detection device, in which FIG. 1 is a schematic configuration diagram, FIG. 2 is a diagram showing a cassette with a 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 schematic configuration diagram,
FIG. 5 is a circuit configuration diagram, and FIG. 6 is a flowchart showing the operation. DESCRIPTION OF SYMBOLS 1... Copying machine body, 6... Cassette, 8... Control circuit, 9... Comparison circuit, 11-1 to 11-N...
…LED.

Claims (1)

[Claims] 1. A comparator circuit having one input terminal connected to a reference voltage source, a capacitor connected to the other input terminal of the comparator circuit, and a capacitor disposed on the paper cassette side and connected to the copying machine. A resistive element connected in parallel or series to the capacitor in accordance with the cassette equipment, a counting circuit for counting the discharging or charging time of the capacitor until the output signal of the comparator circuit is generated, and a counter for the counting circuit. A cassette size detection device for a copying machine, characterized in that the cassette size is detected and displayed according to the resistance value of a resistance element arranged on the cassette side, and the cassette size is detected and displayed according to the resistance value of a resistance element arranged on the cassette side. Device.