JPH1078622A - Sensor signal transmission circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify constitution and to improve reliability by connecting between the output side of a multiinput adder circuit and the input side of a waveform shaping circuit and between the output side of the waveform shaping circuit to the input side of a time division register circuit through a single signal line. SOLUTION: The multiinput adder circuit 4 arithmetically processes the addition of output signals inputted from plural original size detection sensor circuits 1a, 1b...1n and converts and outputs the result to a single output signal. The output side of the circuit 4 is connected to the circuit 6 through the single signal line 5, and the output side of the circuit 6 is connected to the time division register circuit 8 through the single signal line 7. The input side of the circuit 8 has a single input and the output side thereof has the outputs equal to or above the number of the circuits 1a, 1b...1n so as to obtain signals DO1, DO2...DOn one-to-one corresponding to the output signals from the circuits 1a, 1b...1n.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading apparatus such as an electrophotographic copying machine or a scanner, which outputs signals from various sensor circuits including a document size detecting circuit for detecting the size of a document when reading the document. And a sensor signal transmission circuit for transmitting a signal to a control circuit for controlling an entire system such as a copying machine and a scanner.

[0002]

2. Description of the Related Art As shown in FIG. 10, a conventional sensor signal transmission circuit used for detecting a document size is composed of 101a and 101a.
The output signals of the sensor circuits including the original size detection sensor circuits indicated by b, 101n are 102a, 102b, 10n.
105a, 10a, 10a, which are transmitted through the same number of transmission lines as the plurality of sensor circuits indicated by 2n and are separately connected to each sensor circuit.
5b and 105n, outputs DO1, DO2, and DO3, each of which is shaped into a digital waveform for each sensor circuit by a waveform shaping circuit.
DOn is taken into a control circuit of the whole system such as a copying machine or a scanner, and is subjected to signal processing as input information for a control operation. The size of the document currently placed on the platen glass is, for example, A4 or A3. If the sensor circuit is used for detecting, for example, a cassette size other than the document size, the state of the detection target of the sensor circuit is detected.

[0003]

In a conventional sensor signal transmission circuit for transmitting a signal of a sensor circuit such as a document size detection circuit, (1) waveforms corresponding to the number of sensor circuits including the document size detection sensor circuit A shaping circuit is required, which increases costs and lowers reliability. (2) Since the number of signal lines for transmitting signals from the sensor circuit including the document size detection sensor circuit needs to be the same as the number of sensor circuits, the number of harnesses serving as signal lines for wiring is large, and Since the number of locations where failures such as poor connection of the connection connector occur, the reliability is reduced and the total length of the wiring is increased, which causes an increase in cost. (3) From the sensor circuit via the signal line (harness),
Since the number of times of the operation test from the waveform shaping circuit to the input terminal of the control circuit is the same as that of the sensor circuit, the number of manufacturing steps is increased, which causes a cost increase. Had such a problem.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a sensor signal transmission circuit having a simple configuration and improved reliability.

[0005]

In order to solve this problem, a sensor signal transmission circuit according to the present invention comprises a plurality of sensor circuits including a plurality of original size detection sensor circuits. It is composed of a parallel signal that is an output signal, and is connected to the parallel input serial output means such as the other input addition circuit connected next and the parallel connection circuit at the output side of the sensor circuit according to the generation time of the output signal of the sensor circuit. After converting to a serial signal with a slightly different time and transmitting it as a serial signal, the serial signal is converted into a serial signal by a serial input parallel output means such as a time division register circuit to a time corresponding to the generation time of the output signal of each sensor circuit. Restores only the output signal of
A signal similar to the output signal at the output side of the sensor means is obtained.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a document size detecting sensor circuit which is provided in plurality for detecting a document size and whose output signal generation time is slightly different from each other; A multi-input addition circuit having an output of, a waveform shaping circuit for converting a signal waveform into a digital waveform by a preset threshold value, and a single number of inputs and outputs equal to or more than the number of document size detection sensor circuits. The multi-input adder circuit converts the input output signals of the plurality of original size detection sensor circuits into a single number of output signals and outputs the single output signal. The register circuit converts each output signal of the document size detection sensor circuit into a signal corresponding to one-to-one and outputs the signal to each output. The output side of the document size detection sensor circuit is a multi-input addition circuit. The input side is connected one-to-one, the input side of the waveform shaping circuit is connected to the output side of a multi-input addition circuit, the output side is connected to the input side of a time-division register circuit, and the waveform from the output side of the multi-input addition circuit. A single signal line may be connected between the input side of the waveform shaping circuit and the area between the output side of the waveform shaping circuit and the input side of the time division register circuit.

A document size detection sensor circuit which is provided in plurality for detecting a document size and whose output signal generation time is slightly different from each other, and a waveform shaping circuit which converts a signal waveform into a digital waveform by a preset threshold value are provided. , A time-division register circuit having a single number of inputs and outputs equal to or greater than the number of document size detection sensor circuits.
The signal is converted into a signal corresponding to one to one and output to each output. The output side of the original size detection sensor circuit is connected in parallel, and the input side of the waveform shaping circuit is connected to the output side of the original size detection sensor circuit connected in parallel. The input side of the time-sharing register circuit is connected to the output side. The input side of the time-sharing register circuit is connected from the output side of the original size detection sensor circuit connected in parallel to the input side of the waveform shaping circuit and from the output side of the waveform shaping circuit. The connection up to the side may be connected by a single number of signal lines.

Further, a sensor means comprising a plurality of sensor circuits, having at least the same number of outputs as the sensor circuits, and outputting each output signal of the sensor circuits as a first parallel signal;
A parallel input / serial output converter for converting the first parallel signal into a serial signal and having the same number of inputs as the sensor circuit, and outputting the serial signal; a serial signal transmitting means for transmitting and outputting the serial signal; And a serial input / parallel output means for converting the serial signal into a second parallel signal corresponding to the first parallel signal on a one-to-one basis and outputting the second parallel signal. The first parallel signal is provided for each sensor circuit. The generation time of each output signal is slightly different, so that the serial signal has a signal at a time corresponding to the generation time of each output signal for each sensor circuit, and the output side of the sensor means is the input of the parallel input serial output conversion means. And the serial signal transmission means is connected between the output side of the parallel input serial output conversion means and the input side of the serial input parallel output means. In which but connected.

In the sensor signal transmission circuit using the multi-input addition circuit configured as described above, a signal from the output side of the multi-input addition circuit to the input side of the waveform shaping circuit and from the output side of the waveform shaping circuit. Sensor signals can be transmitted by a single number of signal lines up to the input side of the time division register circuit.

In a sensor signal transmission circuit using a document size detection sensor circuit connected in parallel, a signal from an output side of the document size detection sensor circuit connected in parallel to an input side of the waveform shaping circuit and a signal shaping circuit of the waveform shaping circuit are connected. A sensor signal can be transmitted by a single signal line between the output side and the input side of the time division register circuit.

Further, the sensor signal transmission circuit can transmit a serial signal from the output side of the parallel input serial output conversion means to the input side of the serial input parallel output means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1a, 1b, 1n
Is a document size detection sensor circuit, which is installed as necessary to detect the size of the document placed on a document reading device such as a copier or scanner, and is a control signal that operates at slightly different output signal generation times. And control terminals AOS1, AOS2, and AOSn for connecting
1, AOS2 and AOSn are connected to a control circuit for controlling the entire system such as a copying machine. Outputs of the original size detection sensor circuits 1a, 1b, and 1n are output to 2a, 2b, and 2n, and the outline is as shown in FIG. For example, the document size detection sensor circuit 1a receives a control signal from the control circuit to the control terminal AOS1 at time t1 to t2, and outputs an output signal to the output 2a depending on the presence or absence of a detection target of the document size detection sensor circuit 1a. Occurs or does not occur. The time between t1 and t2 is controlled by the control circuit so that the other original size detection sensor circuits 1b-1
A time that does not coincide with the generation time of the n output signal is set. The outputs of the original size detection sensor circuits 1a, 1b, and 1n are output from the original size detection sensor circuits 1a, 1b, and 1n, respectively.
Are connected to a multi-input addition circuit 4 which is an example of a parallel input serial output conversion means having the same number of inputs or more as the number of inputs.

The multi-input adding circuit 4 has a single output on the output side 5 and is connected to a waveform shaping circuit 6 having a single input. In the multi-input adding circuit 4, the output signals of the plurality of original size detecting sensor circuits inputted are converted into a single number of output signals by the arithmetic processing of addition and output, and the outline is shown in FIG. Is shown. The outputs of the original size detection sensor circuits 1a, 1b, and 1n do not overlap on the same signal line 5, and the presence or absence of a signal is determined at each time of t1 to t2, t3 to t4, and tn to tm according to the presence or absence of the detection target. 2A, the input of the multi-input addition circuit 4 is shown in FIG. 2A, and the output is shown in FIG. 2B. It can be seen that the addition operation has been performed. The output side of the multi-input addition circuit 4 is a single signal line 5
To the waveform shaping circuit 6.

The waveform shaping circuit 6 converts the input signal into a digital waveform having a sharp rising or falling edge according to a preset threshold value, and outputs the digital signal.

The outline is shown in FIG. For example, the output of the original size detection sensor circuit 1a is t1 to t2.
Occurred at the time of
The signal is a digital waveform signal which is generated from a time t1 'which is slightly later than 1 to a time t2' which is slightly earlier than t2, and the other original size detection sensor circuits 1b operate from t3 'to t3.
4 ', the document size detection sensor circuit 1n is tn' to tm '
Becomes The output side of the waveform shaping circuit 6 is connected to the time division register circuit 8 by a single signal line 7.

The input side of the time division register circuit 8, which is an example of the serial input / parallel output conversion means, has a single input, and the output side has the same number or more of outputs as the original size detection sensor circuits 1a, 1b, 1n. Document size detection sensor circuit 1a,
1b, a signal DO corresponding to each output signal on a one-to-one basis.
1, DO2 and DOn are obtained and transmitted to the control circuit as data signals. In the time division register circuit 8, the input waveform is the waveform 7 in FIG.
(D), which is converted into a signal corresponding to each output signal of the original size detection sensor circuit on a one-to-one basis and output to each output,
T1 ′ to t2 ′, t2 without overlapping on the same signal line 7
In each of the times 3 ′ to t4 ′ and tn ′ to tm ′, the presence or absence of a signal depending on the presence or absence of the detection target of the original size detection sensor circuits 1a, 1b and 1n is changed to t1 ′ to t1.
Output to DO1 during time 2 ', output to DO2 during time t3' to t4 ', and DOn during time tn' to tm '.
To the original document size detection sensor circuits 1a, 1a
Data signals corresponding to the output signals b, 1n on a one-to-one basis are obtained. As a result, the data signals DO1, DO2, and DOn are transmitted to the control circuit, and are used to detect whether the size of the document placed on the platen glass is, for example, A4 or A3.

FIG. 3A shows a second embodiment, in which 1a,
Reference numeral 1b and 1n denote document size detection sensor circuits, which are provided as necessary to detect the size of a document placed on a document reading device such as a copier or a scanner, and operate at times when output signal generation times are slightly different. It has control terminals AOS1, AOS2 and AOSn for connecting control signals to be controlled, and the control terminals AOS1, AOS2 and AOSn are connected to a control circuit for controlling the entire system such as a copying machine. The output of the original size detection sensor circuits 1a, 1b and 1n is 2a,
After being output to 2b and 2n and connected in parallel, they are connected to the input of the waveform shaping circuit 6 by a single signal line. For example,
FIG. 3B shows an output waveform of the original size detection sensor circuit 1a. The control circuit outputs a control terminal AOS1 from time t1 to time t2.
Control signal is applied to the document size detection sensor circuit 1
Depending on the presence or absence of the detection target a, the output signal may or may not be generated at 2a. The time from t1 to t2 is set by the control circuit so as not to coincide with the generation time of the output signal of the other original size detection sensor circuits 1b to 1n. Similarly, FIG. 3C shows an output waveform of the original size detection sensor circuit 1b, and FIG. 3D shows an output waveform of the original size detection sensor circuit 1n. Further, since the outputs of the original size detection sensor circuits 1a, 1b, and 1n are connected in parallel, the waveform at the portion connected in parallel and connected to the input of the waveform shaping circuit is as shown in FIG. Here, the respective outputs of the original size detection sensor circuits 1a, 1b, and 1n do not overlap on the same signal line 5 and t1 to t2, t2
In each of the times 3 to t4 and tn to tm, the presence or absence of a detection object indicates whether a signal is present or not. The outputs of the original size detection sensor circuits 1a, 1b, and 1n are connected in parallel to calculate the addition. It can be seen that the processing has been performed.

The waveform shaping circuit 6 converts the input signal into a digital waveform having a sharp rising or falling edge according to a preset threshold value, and outputs the digital waveform.

The outline is shown in FIG. For example, the output of the original size detection sensor circuit 1a is t1 to t2.
Occurred at the time of
The signal is a digital waveform signal which is generated from a time t1 'which is slightly later than 1 to a time t2' which is slightly earlier than t2, and the other original size detection sensor circuits 1b operate from t3 'to t3.
4 ', the document size detection sensor circuit 1n is tn' to tm '
Becomes The output side of the waveform shaping circuit 6 is connected to the time division register circuit 8 by a single signal line 7.

The input side of the time-division register circuit 8, which is an example of the serial input / parallel output conversion means, has a single input, and the output side has the same number or more of outputs as the original size detection sensor circuits 1a, 1b, 1n. Document size detection sensor circuit 1a,
1b, a signal DO corresponding to each output signal on a one-to-one basis.
1, DO2 and DOn are obtained and transmitted to the control circuit as data signals. In the time division register circuit 8, the input waveform is the waveform 7 in FIG.
(D), which is converted into a signal corresponding to each output signal of the original size detection sensor circuit on a one-to-one basis and output to each output,
T1 ′ to t2 ′, t2 without overlapping on the same signal line 7
In each of the times 3 ′ to t4 ′ and tn ′ to tm ′, the presence or absence of a signal depending on the presence or absence of the detection target of the original size detection sensor circuits 1a, 1b and 1n is changed to t1 ′ to t1.
Output to DO1 during time 2 ', output to DO2 during time t3' to t4 ', and DOn during time tn' to tm '.
To the original document size detection sensor circuits 1a, 1a
Data signals corresponding to the output signals b, 1n on a one-to-one basis are obtained. As a result, the data signals DO1, DO2, and DOn are transmitted to the control circuit, and are used to detect whether the size of the document placed on the platen glass is, for example, A4 or A3.

FIG. 4A shows a third embodiment, in which a plurality of sensor means 12 are provided as necessary to detect the size of a document placed on a document reading device such as a copying machine or a scanner. The sensor circuit includes a sensor circuit 1, a sensor circuit 2, a sensor circuit n, and a plurality of sensor circuits for detecting a traveling position of a light source for reading a document and detecting a lighting failure of the light source. It has control terminals 11a, 11b, and 11n for connecting control signals of a control circuit for controlling an entire system such as a copying machine operated at different times, and the control terminals 11a, 11b, and 11n are control circuits for the entire system such as a copying machine. It is connected to the. The outputs of the sensor circuit 1, the sensor circuit 2, and the sensor circuit n are 13a, 13
b, 13n, and the outline is as shown in FIG. For example, the sensor circuit 1 receives a control signal from the control circuit to the control terminal 11a at time t1 to t2, and outputs an output signal of 13 depending on the presence or absence of the detection target of the sensor circuit 1.
a or not. Also, this t1
The time from t2 to t2 is set by the control circuit so as not to coincide with the generation times of the outputs 13b to 13n of the other sensor circuits. Thus, the outputs 13a, 13b of the sensor means,
Each output of 13n is a parallel signal, and the parallel signal which is the output of this sensor circuit is referred to as a first parallel signal to distinguish it from another parallel signal described later. The output of the sensor means is connected to the parallel input serial output conversion means 14 of the parallel input serial output conversion circuit having the same number of inputs or more as the number of sensor circuits 1 to n.

The output side 15 of the parallel input / serial output conversion means 14 has a single number of outputs, and is connected via a serial signal transmission means 16 to a serial input / parallel output conversion means 18 having a single number of inputs. . The parallel input / serial output conversion means 14 converts the first parallel signal, which is the output signal of the plurality of sensor circuits, into a serial output signal and outputs it. The outline is shown in FIG. 4 (b).

Each output of the sensor means 12 is not overlapped on the same signal line 5 and t1 to t2, t3 to t4, tn to tm
At each of the times, the presence or absence of a signal appears depending on the presence or absence of the detection target, and the input / output of the parallel input / serial output conversion means 14 appears.

The input side of the serial input / parallel output conversion means 18 is a single number, and the output side is the output 13 of the sensor means 12.
a, 13b, and 13n, and outputs a second parallel signal corresponding to each output signal of the outputs 13a, 13b, and 13n of the sensor means 12 on a one-to-one basis.
0a, 20b, and 20n, and transmitted to the control circuit as a data signal. The input / output waveform of the serial input / parallel output conversion means 18 is shown in FIG.

According to this configuration, the second parallel signal corresponding to the first parallel signal which is each output signal of the sensor means including various sensor circuits including the original size detecting sensor circuit has a one-to-one correspondence.
And output at the respective times t1 to t2, t3 to t4 and tn to tm without overlapping on the same signal line 7 depending on the presence or absence of the detection target of the various sensor circuits of the sensor means 12. That occurred as the presence or absence of
During the period from 1 to t2, the signal is output to 20a, during the period from t3 to t4, to 20b, and during the period from tn to tm, to 20n. A second parallel signal, which is a data signal corresponding to one, is obtained.

As a result, the data signals of 20a, 20b and 20n are transmitted to the control circuit, and the size of the original placed on the platen glass is, for example, A4 or A3, or the scanning position of the original reading light source. Is used to detect information such as where the sensor circuit is located.

FIGS. 5 (a) to 5 (d) show a plurality of sensor circuits, if necessary, for detecting the size of a document placed on a document reading device such as a copying machine or a scanner, and a light source for reading the document. One specific example of a plurality of sensor circuits for detecting a traveling position of a vehicle and detecting a lighting failure of a light source will be described. FIG.
In (a), S1 is a light emitting element such as an LED, and S2 is a light receiving element such as a phototransistor. AOS1 is a control terminal for connecting a control signal of a control circuit for controlling an entire system such as a copying machine. AOSS1, which is an output terminal of a signal output of the sensor circuit, is connected to the AOSS1 for a time that does not overlap with other sensor circuits. At intervals, control signals are applied. As a result, depending on the presence / absence of a detection target of this sensor circuit, current flows or does not flow through the light receiving element S2, and AOSS
1, the output signal of the sensor circuit is obtained as the presence or absence of the output signal. FIG. 5B shows that the output of FIG. 5A has a high gain amplifier S3 such as an operational amplifier and a feedback resistor R3.
5 is connected to the inverting amplifier circuit composed of
An example in which the phase of the output signal in (a) is inverted and an output signal whose output level is changed is obtained.

FIG. 5C shows a waveform shaping circuit in which a high-gain amplifier S4 such as an operational amplifier and a reference voltage obtained by dividing the resistances of the resistors R4 and R5 are connected to the output of FIG. AOS1 output signal of analog waveform and digital waveform
Here is an example of output to In FIG. 5D, when there is no inverting amplifier circuit in FIG. 5C, a digital signal whose phase is inverted from that of the output signal in FIG. 5C is obtained at the output terminal AOS1. There are various combinations in designing how far to process the signal waveform after the output of the light receiving element S2, but the sensor circuit may be any circuit as long as it has the basic configuration shown in FIG.

FIG. 6A shows a multi-input addition circuit which is an example of a parallel input serial output conversion circuit. The outputs of the plurality of sensor circuits are connected to AOSS1, AOSS2, and AOSSn. The resistors R11, R12, R1n, and the resistor R20 perform a voltage dividing operation on the input side. The output signal is output to the output terminal AOSS by controlling the gain of the high-gain amplifier S11. Since the output signals from the sensor circuit are input to the input terminals AOSS1, AOSS2, and AOSSn at different times, no signal is input to the other AOSS2 to AOSSn during the time when the signal is input to AOSS1. That is, it is similar to grounding. For example, during the time when a signal is transmitted to AOSS1, this input signal is connected to a resistor R12,.
If the parallel resistance value of R1, n1 and R21 is RP1, the voltage is divided by the resistor R11 and the resistor RP1 and enters the input of the non-inverting amplifier circuit constituted by the amplifier S11 and the resistors R21 and R22. Is represented by G1 and is represented by the following relational expression.

G1 = (1 + R21 / R22) × RP1 ×
(RP1 + R11) Here, when the resistors R11, R12 to R1n, and R21 have the same resistance value, the parallel resistance value when there is a signal in AOSS2 and the parallel resistance value when there is a signal in AOSSn are all the same. Therefore, each gain becomes the same. As a result, since the amplifying operations from the respective input terminals have the same relationship, the signals input to each of them have one output terminal AOSS.
Then, an output signal obtained by multiplying each input signal by G1 is obtained.
FIG. 6C shows the input / output relationship of the multi-input addition circuit. FIG. 6B shows a one-input adding circuit when the input is one terminal. This one-input addition circuit may be connected to a stage preceding the waveform shaping circuit 6 in FIG.

FIG. 7A shows one example of a waveform shaping circuit. S4 is a high-gain amplifier such as an operational amplifier. When the voltage of the signal waveform applied to the input AOSS is higher than the reference voltage V1 obtained by dividing the voltage VC2 by the resistors R4 and R5, it is lower than LOW and V1. Is shaped into a digital waveform that becomes HIGH. This state is shown in FIG.

Although FIG. 7A shows the case where the input AOSS is connected to the inverting input of the amplifier S4, the input AOSS may be connected to the non-inverting input, and the connection between the input AOSS and the reference voltage V1 is reversed. In this case, the relationship between the input waveform and the output waveform is
The output waveform shown in FIG. 7B is a waveform in which LOW and HIGH are reversed, and which one is adopted is determined in circuit design.

FIG. 8 shows an embodiment of a time division register circuit which is an example of the serial input / parallel output conversion means. A
An input is connected to the OS, a control signal from the control circuit is connected to AO1 to AOn, a reset signal is connected to the IRES from the control circuit, and a data signal read line of the control circuit is connected to DO1 to DOn. You. S11 to S1n
Is the same number of flip-flop circuits as the number of sensors. When a signal is applied to the T terminal and the state of the D terminal is HIGH, Q
The terminal is HIGH, and if the state of the D terminal is LOW, the Q terminal is LOW. When a signal is applied to the IRES, the signal at the Q terminal is reset to the original state of LOW. The input AOS corresponds to the presence or absence of an output signal depending on the presence or absence of a detection target of a plurality of sensor circuits, and operates only during the operation time of the sensor circuit controlled by the control circuit. The operation time is a digital signal shifted for each sensor circuit. Will enter. For example,
The operation of the first sensor circuit is performed when the control signal is present in AO1. If the detection target is detected by the first sensor circuit, the output of the sensor circuit appears at the timing when the control signal is present in AO1. And a HIGH signal is transmitted to the D terminal of the flip-flop circuit S11. At this time, among the control signals of AO1 to AOn, only the signal AO1 has a signal. The signal is transmitted,
The flip-flop circuit S11 operates, and the Q terminal is set to HIG.
H, and a signal appears on DO1. Next, at a timing when the control signal is present in AO2, if a detection target can be detected by the second sensor circuit, a HIGH signal is transmitted to the D terminal of the flip-flop circuit S12.
Since the control signal of O1 to AOn has a signal only in AO2, the control signal is transmitted from AO2 to the T terminal of the flip-flop circuit S12, and the flip-flop circuit S1
2 operates, the Q terminal becomes HIGH, and a signal appears on DO2. Such an operation is continued and the control signals are AO1 to AO.
Control signals AO1 to AO1
The sensor circuit corresponding to the operation of AOn operates, the flip-flop circuits S11 to S1n operate correspondingly, and DO1
To DOn, an output corresponding to the sensor circuit is obtained.

When a series of operations of the sensor circuit is completed, I
A signal is applied to the RES terminal, and the flip-flop circuit S1
The outputs Q of 1 to S1n are reset to prepare for the next operation of the sensor circuit. FIG. 9 shows an outline of the waveform of each part in FIGS. 5 to 8 which is a specific example.

[0035]

The present invention is embodied in the form described above and has the following effects.

A configuration in which a single signal line is connected between the output side of the multi-input adding circuit and the input side of the waveform shaping circuit and between the output side of the waveform shaping circuit and the input side of the time division register circuit. As a result, the number of signal lines for transmitting signals from the multi-input adding circuit to the time-division register circuit becomes a single pair, and the following effects are obtained as compared with the case of transmitting the same number of signal lines as the conventional document size detection sensor circuit. . (1) The number of waveform shaping circuits equal to the number of sensor circuits including the document size detection sensor circuit is only one waveform shaping circuit, so that cost reduction and reliability improvement can be realized. (2) The number of harnesses required for the sensor circuit including the original size detection sensor circuit can be transmitted only by a pair of harnesses, so that the output signals of the sensor circuits can be transmitted in a pair. The number of harnesses and the number of connectors for connecting the harnesses can be reduced, and the reliability can be improved by reducing costs by reducing the number of harnesses and reducing failures such as poor contact due to the reduction in the number of connectors of the harnesses. (3) The operation test of the transmission line from the waveform shaping circuit to the input terminal of the control circuit via the signal line (harness) requires the same number of times as that of the sensor circuit. Since the transmission is performed, the operation test of the transmission line can be performed only once,
Inspection man-hours required for manufacturing are reduced, and cost reduction can be realized.

Further, after the output side of the sensor circuit including the original size detection sensor circuit is connected in parallel to the input side of the waveform shaping circuit and between the output side of the waveform shaping circuit and the input side of the time division register circuit. The configuration in which the signal lines are connected by a single number of signal lines makes the number of signal lines one pair, and the following effects are obtained as compared with the case where the signal is transmitted by the same number of signal lines as the conventional document size detection sensor circuit. (1) The number of waveform shaping circuits equal to the number of sensor circuits including the document size detection sensor circuit is only one waveform shaping circuit, so that cost reduction and reliability improvement can be realized. (2) The number of harnesses required for the sensor circuit including the original size detection sensor circuit can be transmitted only by a pair of harnesses, so that the output signals of the sensor circuits can be transmitted in a pair. The number of harnesses and the number of connectors for connecting the harnesses can be reduced, and the reliability can be improved by reducing costs by reducing the number of harnesses and reducing failures such as poor contact due to the reduction in the number of connectors of the harnesses. (3) The operation test of the transmission line from the waveform shaping circuit to the input terminal of the control circuit via the signal line (harness) requires the same number of times as that of the sensor circuit. Since the transmission is performed, the operation test of the transmission line can be performed only once,
Inspection man-hours required for manufacturing are reduced, and cost reduction can be realized.

Further, an output side of a parallel input serial output conversion means having the same number or more inputs as the sensor circuit and converting the first parallel signal into a serial signal and outputting the serial signal;
Outputs more than the same number of sensor circuits and outputs serial signals
A serial signal transmitting means for transmitting and outputting a serial signal between an input side of a serial input / parallel output means for converting and outputting a second parallel signal corresponding to the parallel signal on a one-to-one basis. Thus, a serial signal can be transmitted from the output side of the parallel input serial output conversion means to the input side of the serial input parallel output means.

With such a configuration, transmission by serial signals is possible, so that only one pair of signal lines is required, and the following effects are obtained as compared with the case of transmission by conventional parallel signals. (1) There is only one waveform shaping circuit as many as the number of sensor circuits connected to each parallel signal line,
The cost can be reduced and the reliability can be improved. (2) When transmitting parallel signals, the number of signal lines is required as many as the number of sensor circuits. However, by transmitting serial signals, the number of signal lines can be increased to one, and the number of wiring harnesses can be reduced. The number of harness connection connectors can be reduced, and the reliability can be improved by reducing costs due to a decrease in the number of harnesses and failures such as poor contact due to a decrease in the number of harness connectors. (3) From the sensor circuit via the signal line (harness),
The operation test on each path of each parallel signal from the waveform shaping circuit to the input terminal of the control circuit required the same number of times as that of the sensor circuit. The required number of inspection work is reduced,
Cost increase can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of a first embodiment of a sensor signal transmission circuit of the present invention.

FIG. 2 is a waveform chart of a first embodiment of the sensor signal transmission circuit of the present invention.

FIG. 3 is an overall schematic diagram of a second embodiment of the sensor signal transmission circuit of the present invention.

FIG. 4 is an overall schematic diagram of a third embodiment of the sensor signal transmission circuit of the present invention.

FIG. 5 is a specific sensor circuit diagram of the present invention.

FIG. 6 is a specific multi-input addition circuit diagram of the present invention.

FIG. 7 is a specific waveform shaping circuit diagram of the present invention.

FIG. 8 is a specific time division register circuit diagram of the present invention.

FIG. 9 is a schematic diagram of a signal waveform in each part of the sensor signal transmission circuit of the present invention.

FIG. 10 is an overall schematic diagram of a conventional sensor signal transmission circuit.

[Description of Signs] 1a, 1b, 1n Document size detection sensor circuit 4 Other input addition circuit 6 Waveform shaping circuit 8 Time division register circuit 12 Sensor means 14 Parallel input serial output conversion means 16 Serial signal transmission means 18 Serial input parallel output conversion means

Claims (3)

[Claims] A plurality of document size detection sensor circuits are provided for detecting a document size and output signals have slightly different generation times, and a multiplicity having the same number or more inputs and a single number of outputs as the document size detection sensor circuits is provided. An input adding circuit, a waveform shaping circuit for converting a signal waveform into a digital waveform according to a preset threshold value, and a time-sharing register having a single number of inputs and outputs equal to or greater than the number of the document size detection sensor circuits The output side of the original size detection sensor circuit is connected to the input side of the multi-input addition circuit in a one-to-one relationship, and the input side of the waveform shaping circuit is connected to the output side of the multi-input addition circuit. The input side of the time-division register circuit is connected to the output side, and the multi-input addition circuit performs an arithmetic operation for adding the output signals of the plurality of original size detection sensor circuits input thereto. The time-division register circuit converts the signal into a signal corresponding to each output signal of the document size detection sensor circuit on a one-to-one basis and outputs the signal to each output. Document size detection in which a single signal line is provided between the output side of the multi-input adding circuit and the input side of the waveform shaping circuit and between the output side of the waveform shaping circuit and the input side of the time division register circuit. Signal transmission circuit used for 2. A document size detection sensor circuit which is provided in plurality for detecting a document size and whose output signal generation time is slightly different from each other, and a waveform shaping circuit which converts a signal waveform into a digital waveform by a preset threshold value. A time-division register circuit having a single number of inputs and an output equal to or greater than the number of the document size detection sensor circuits, the output side of the document size detection sensor circuit being connected in parallel, and the input of the waveform shaping circuit. Side is connected to the output side of the document size detection sensor circuit connected in parallel, and the output side is connected to the input side of the time division register circuit, and the time division register circuit applies to each output signal of the document size detection sensor circuit. 1
The signal is converted to a signal corresponding to one to one and output to each output. The signal is output from the output side of the original size detection sensor circuit connected in parallel to the input side of the waveform shaping circuit and from the output side of the waveform shaping circuit. A sensor signal transmission circuit used for detecting a document size in which a single signal line extends from the divided register circuit to the input side. 3. A sensor means comprising a plurality of sensor circuits, having at least the same number of outputs as the sensor circuits, outputting each output signal of the sensor circuits as a first parallel signal, and providing at least the same number of inputs as the sensor circuits. A parallel input / serial output conversion means for converting the first parallel signal into a serial signal and outputting the serial signal; a serial signal transmission means for transmitting and outputting the serial signal; and having at least as many outputs as the sensor circuit. Serial input / parallel output means for converting a serial signal into a second parallel signal corresponding to the first parallel signal on a one-to-one basis, and outputting the converted signal. Connected to the input side of the means, the output side of the parallel input serial output conversion means and the input side of the serial input parallel output means The serial signal transmission unit is connected between the first parallel signal and the output time of each of the first parallel signals is slightly different for each sensor circuit, and the serial signal is each of the output signals for each sensor circuit. Sensor signal transmission circuit in which a signal exists at a time corresponding to the occurrence time of the sensor signal.