JP2675395B2 - Automatic document size detection method and copy start control device for copy machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an automatic document size detection method and a copying machine employing this method.

(B) Conventional technology As a conventional document size detecting method of a copying machine, a reflection type optical sensor is built in a platen cover to detect reflection on the back surface of a document (see Japanese Patent Application Laid-Open No. 54-72323). ,
A detection method that has a light receiving sensor inside the platen cover, arranges a light emitting unit on the lower surface of the original, and uses the light shielding of the original
No. 50-1242), a method of arranging a reflection type optical sensor on the lower surface of the original to detect reflection on the original surface (Japanese Patent Laid-Open No. 56-7884
Many detection means are known, such as Japanese Patent Publication No. 9).

By the way, in the document size detecting method of the type in which the reflection type optical sensor is built in the platen cover, the document size is detected unless the platen cover is closed and the reflection type sensor faces the back side of the document. I can't do that. Therefore, conventionally, an open / close detection switch that is turned on / off by opening and closing the platen cover is provided. However, in the case of a thick original, the open / close detection switch may not operate correctly, and the open / close switch and its actuator may have a complicated structure. Further, if there is strong disturbance light, there is a problem that the reflection type optical sensor responds irrespective of the reflection of the document, thereby causing erroneous detection.

(C) Problems to be Solved by the Invention In addition to removing components with a complicated structure such as a platen cover opening / closing detection switch and its actuator, malfunctions in document detection for thick documents and erroneous detections occurring during platen cover opening / closing operations Also, the malfunction of the reflection type optical sensor due to the influence of ambient light is prevented, and the stable document size detection is performed with a simple structure.

(D) Means for Solving the Problems The present invention provides a platen on which a document is placed, a platen cover that is openably and closably mounted on the platen, and a plurality of plates of different sizes that are provided on the platen cover. In an automatic document size detecting method comprising a plurality of optical document detecting means for detecting various kinds of documents,
The automatic document size detection method is characterized by detecting the document size after detecting that the platen cover is closed by a detection unit that detects the smallest document among the optical document detection units.

Further, the present invention is provided with a platen on which a document is placed, a platen cover that is openably and closably mounted on the platen, and a platen cover, and is for detecting a plurality of types of documents of different sizes. A copier having a plurality of optical document detecting means, after detecting that the platen cover is closed by the detecting means for detecting the smallest document among the optical document detecting means. A copy start control device for a copying machine, which is provided with means for detecting a document size and starting a copy operation based on the detection signal.

(E) Action As a trigger signal for starting the document size detection operation, only the platen cover open / close is used, and a reflection type mounted on the platen cover provided for document size detection is used without using a separate open / close switch. Focusing on the fact that there is a sensor that responds to any document size among the optical sensors, the on / off signal of that sensor is used. Further, by repeating the document size detection operation until the copy start key is pressed (strictly until the paper feed operation is started), unstable detection data when the platen cover is opened and closed can be eliminated. it can. In addition, in order to determine whether the signal of the light receiving sensor of the reflection type optical sensor is truly due to the reflection of the document or the ambient light, the emission side is turned on / off to determine the presence or absence of ambient light. , Prevents false detection due to ambient light.

(F) Embodiment FIG. 1 is a perspective view of a copying machine showing an embodiment of the present invention. An original table (platen) 2 made of a transparent glass plate is fixedly provided on the upper surface of the copying machine body 1. A stopper 4 for aligning the position of the document 3 is provided on the left side of the document table 2, and the operator sets the document 3 so that the center mark 5 at the center of the stopper 4 aligns the center of the document 3. To do. A platen cover 6 is attached to the upper portion of the document table 2 by a hinge at the end so as to be freely opened and closed. Inside the platen cover 6, sensors SN1, SN2, SN3, SN4, and SN5 for detecting a document size are provided.
Also, a switch SW for selecting automatic paper feeding on the operation panel 9
1 is provided.

Cassettes 7 and 8 for setting copy sheets are detachably mounted on the side surface of the copying machine main body 1, and one of them can be selected by operating a key on an operation panel 9. Also, a cassette containing the same size of paper as the original size is automatically selected by automatic document size detection described later.

FIGS. 2A and 2B are a sectional view and a perspective view of a sensor provided in the platen cover 6. It should be noted that this figure is upside down from FIG. The sensor includes a light emitting diode 11 and a light receiving phototransistor 12. The sensor cover 10 has holes 11 for emitting and receiving light.
a and 12a are respectively provided, and through the white semi-transparent film 6a attached to the lower surface of the platen cover 6,
The original is detected by detecting the reflected light from the original. The white translucent film 6a is necessary to prevent the sensor part from being copied in black. The sensor is connected to the detection circuit via a lead 13.

FIG. 3 shows the arrangement of the sensors when the platen cover 6 is viewed from the top. The sensors SN1 to SN5 are fitted into the platen cover 6 with the surfaces of the holes 11a and 12a facing downward at the illustrated positions. The operator places the platen 2
When a document is placed on the document and the platen cover 6 is closed, one of the sensors SN1 to SN5 on the document reacts according to the document size, and therefore the document size can be detected by the combination.

FIG. 4 is a block diagram of a control unit of the copying machine main body.
The copying machine is controlled by a microcomputer system including the CPU 14. This microcomputer system has a ROM 15 for storing control programs connected to the CPU 14, a temporary storage of data during control by the CPU 14, and an area for various flags necessary for control. The RAM 16 and the CPU 14 included therein are provided with an I / O 17 for controlling input / output of internal equipment of the main body. I / O
A sensor input from the document size detection circuit 18 and an input from the automatic paper feed switch SW1 are connected to the input port 17 and a switching signal for controlling the detection circuit 18 is output from the output port. The ROM 15 stores sensor input data corresponding to each document size, and is used to detect the document size.

FIG. 5 is a circuit diagram showing details of the detection circuit 18. As shown in FIG. The outputs of sensors SN1 to SN5 are comparators 22 and 23, respectively.
(The circuit of SN1 to SN3 is omitted because it is the same as the circuit of SN5), and the reference voltage (about 2.5V) determined by resistors 24 and 25
Depending on whether it is higher or lower, the outputs of comparators 22 and 23 will be “H” or “L” respectively, and CPU14 will be output through I / O17.
It is taken in. Here, when light does not enter from the light receiving holes 12a of the sensors SN1 to SN5, the light receiving element 26 is in a cutoff state, so that the inputs of the comparators 22 and 23 are almost 5V, and the sensor input is "H". Becomes On the other hand, when light enters, the light receiving element becomes conductive depending on its intensity, so the comparator 27 is divided by the resistors 27 and 28.
The input voltage of 22 and 23 decreases, and when a certain amount of strong light enters, the voltage drops below the reference voltage and “L” is obtained as the sensor input. Variable resistor 27
Is for adjusting the sensitivity of the sensor. That is, if the resistance values of the resistors 27 and 28 are large, even the slightest amount of light causes
Since the partial pressure value with 26 becomes small, "L" can be obtained as the sensor input, and the sensitivity increases. Also the resistance
On the contrary, if the resistance value of 27 and 28 is small, the sensitivity decreases.

When the switching signal output from the I / O 17 is “L”, the output voltage of the comparator 19 is “L”, so the transistor
21 turns on, and the sensitivity of sensor SN4 is resistance 27, 28.
The sensitivities of the sensors SN1 to SN5 are the same because they are determined by Further, since the transistor 20 is turned on, the light emitting element 29 is driven. That is, at this time, the original can be detected.

On the other hand, when the switching signal output from the I / O 17 is “H”, the output voltage of the comparator 19 becomes “H” and the transistor 20 is turned off, so that the light emitting element 29 is not driven. Since the transistor 21 is also turned off, the sensitivity of the sensor SN4 is determined by the resistors 27, 28 and 30. That is, the sensitivity is higher than in the state described above. At this time, since the light emitting element 29 is not driven, the light entering the sensor is not the light reflected from the document but the light entering from the outside.
Since this light is weaker than the light reflected from the document in the normal state, only the highly sensitive sensor SN4 detects it. If the platen cover 6 is completely closed,
Since this external light becomes almost zero, the sensor input of the sensor SN4 becomes "H", and it can be confirmed that the platen cover is closed. This check is necessary to prevent the document size from being erroneously detected.

FIG. 6 is a flowchart showing the operation of document size detection. When document size detection is started, first, in step S1, the switching signal is set to "L", and the detection circuit is set to a normal document detection state. Next, in step S2, wait until the sensor SN4 becomes "L" (it will be turned on when a paper of a predetermined size is placed.) The original 3 is correctly set on the original platen 2, and the platen cover 6 is closed. If so, the sensor SN4 is always turned on, so that this can be detected. If the determination in step S2 is YES, the process proceeds to step S3, and it is determined whether the sensor input pattern and the document size data stored in the ROM 15 match. If there is no matching original size, the original may not be set correctly or the platen cover may not be fully closed. Therefore, the process returns to step S2 and starts over. If there is a matching original size, proceed to step S4,
Set the switching signal to "H" to activate the external light detection. Then, in step S5, it is determined whether or not the sensor SN4 is off. If NO, the process returns to step S1, and if YES, the process proceeds to step S6. This makes it possible to avoid erroneous determination even when erroneous detection is made by the relatively strong external light in steps S2 and S3. Then, in step S6, a cassette containing the same paper size as the detected original size is selected.

However, if there is no matching paper, a display notifying the detected original size is displayed on the display unit of the operation panel 9. Then, in step S7, the switching signal is set to "L" to enter the normal document detection state, and in step S8, it is checked whether or not the state of the sensor input has changed. If change, step
Return to S2 and start over. This is a trigger for detecting that the platen cover 6 has been opened. Further, when the platen cover 6 is closed, the sensor input becomes unstable, and even if the document size is erroneously detected, it will be corrected by starting over from here.

If there is no change in the sensor input, proceed to step S8 ′,
Determine whether the automatic start switch SW1 is ON.
If step S8 'is YES, the copying operation is started and NO
If so, the process proceeds to step S9, and it is determined whether or not the start switch has been pressed. NO in this step S9
If so, the process returns to step S8, and if YES, the copying operation is started. As a result, even after the operator operates the operation panel 9 to start copying, if the platen cover 6 is closed before the start of paper feeding, the paper is automatically selected.

(Effect of the Invention) According to the present invention according to claim 1, the switch for detecting the open / closed state of the platen cover, which is conventionally required as the trigger signal for detecting the document size, can be omitted, and the platen cover opening / closing operation It is possible to avoid erroneous detection in an unstable state that is likely to occur in the case of a thick document. Further, it is possible to prevent erroneous detection due to disturbance light or the like, and it is possible to reliably and stably detect a document size that has not existed in the related art. Therefore, it is possible to automatically select copy paper and automatic magnification by more stable automatic detection of original size.
It is possible to realize a copying machine or the like with few miss-copies.

Further, according to the present invention of claim 2, when copying a large number of originals manually, it is not necessary to operate the start button each time, and the copying time can be shortened.

[Brief description of the drawings]

Each of the drawings shows an apparatus embodying the present invention, FIG. 1 is a perspective view of a copying machine showing an embodiment, FIG. 2 is a schematic view of a sensor provided in a platen cover, and FIG. 3 is a platen cover from above. FIG. 4 is a block diagram of the control unit of the copying machine main body, FIG. 5 is a detailed view of the detection circuit, and FIG. 6 is a flow chart showing the operation of detecting the original size. 1 ... copy machine body 2 ... platen (platen) 3 ...
Manuscript, 6 ... platen cover, 10 ... sensor cover,
11,29 …… Light emitting diode, 12,26 …… Phototransistor, 14 …… CPU, 15 …… ROM, 16 …… RAM, 17 …… I / O,
18 …… Document size detection circuit, 19,22,23 …… Comparator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuji Handa 2-18 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (56) Reference JP-A-60-52842 (JP, A) JP Sho 59-140441 (JP, A)

Claims (2)

(57) [Claims] 1. A platen on which a document is placed, a platen cover mounted on the platen so as to be openable and closable, and a platen cover, which are provided on the platen cover for detecting a plurality of types of documents of different sizes, An automatic document size detecting method comprising a plurality of optical document detecting means, wherein the detecting means for detecting the smallest original among the optical document detecting means detects that the platen cover is closed. An automatic document size detecting method, characterized in that the document size is detected after the operation. 2. A platen on which a document is placed, a platen cover that is openably and closably mounted on the platen, and a platen cover that is provided for detecting a plurality of types of documents of different sizes. In a copying machine provided with a plurality of optical original detecting means, after detecting that the platen cover is closed by the detecting means for detecting the smallest original among the optical original detecting means, A copying start control device for a copying machine, comprising means for detecting a document size and starting a copying operation based on the detection signal.