JPH01265270A - Automatic detecting method for original size - Google Patents

Abstract

PURPOSE:To prevent maldetection of original size in unstable conditions where a platen cover is currently opened or closed and where a thick original is copied by continuing to detect original size until the platen cover is closed to operate a paper feeding part. CONSTITUTION:Original size detecting sensors SN1-SN5 are provided inside the platen cover 6, and light reflected from an original is detected through a white translucent film 6a on the back of the platen cover 6. When the original 6 is set to an original platen 2 to close the platen cover 6, the sensor SN3 and/or the sensor SN4 are turned on to detect the original setting. Then, a pattern of sensor input is collated with stored original size data, and collation continues until they agree with each other. Unless the external light detecting sensor SN1 is turned off when the pattern matches to the size, operation returns to an initial step. Consecutively, after recognizing the fact that the sensor input does not change, sheets height to be fed. Thus, maldetection in the unstable conditions can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a method for automatically detecting the size of a document in a copying machine, facsimile machine, etc.

(B) Conventional technology As a conventional document size detection method for copying machines, there is a method in which a reflection type optical sensor is built into the platen cover and the reflection on the back side of the document is detected (see Japanese Patent Laid-Open No. 73623/1983). ), a detection method that uses a light-receiving sensor inside the platen cover, a light-emitting unit placed on the bottom surface of the document, and utilizing the light shielding of the document (see Japanese Patent Application Laid-Open No. 11242/1982), a reflective light sensor placed on the bottom surface of the document However, many detection means are known, such as a method of detecting reflection on the surface of a document (see Japanese Patent Application Laid-open No. 78849/1983).

By the way, in the document size detection method of the type in which a reflective optical sensor is built into the platen cover, the document size is detected unless the platen cover is closed and the reflective sensor is facing the back side of the document. Therefore, conventionally, an opening/closing detection switch is provided which is turned on/off by opening/closing the platen cover. However, if the document is thick, the open/close detection switch may not operate accurately, and the structure becomes complicated because the open/close switch and its actuator must be attached. Furthermore, if there is strong ambient light, there are problems such as false detection due to the reflective optical sensor responding regardless of the reflection from the document.

(c) Problems to be solved by the invention In addition to removing components with a complicated structure such as the detection switch for opening/closing the platen cover and its actuator, malfunctions of w and 1B detection in thick originals, which occur when the platen cover is opened/closed. To prevent erroneous detection and malfunction of a reflective optical sensor due to the influence of ambient light, and to perform stable document size detection with a simple composition.

Furthermore, if the document size is detected while the platen cover is not completely closed over the platen, there is a risk of erroneously determining the size.

In view of the above-mentioned problems, the present invention aims to realize an automatic document size detection method that can particularly prevent misjudgment of document size.

(d) Means for Solving the Problems The present invention comprises a platen on which a document is placed, a platen cover mounted on the platen so as to be openable and closable, and an optical document detection means provided on the platen cover. , a plurality of recording paper storage units, and a paper feeding means, and the optical W
, which feeds paper of a size corresponding to the document size detected by the document detection means, wherein the optical document detection means starts the closing operation of the platen cover over the platen, and then This automatic document size detection method is characterized in that document size detection is executed and controlled until the paper means starts operating.

(e) Function: As a trigger signal to start the original size detection operation, only the opening and closing of the platen cover is used, without using a separate opening/closing switch, the reflection that is attached to the platen cover provided for original size detection. Focusing on the fact that there is a type of optical sensor that responds to any document size, we use the on/off signal of that sensor. Furthermore, by repeating the document size detection operation until the copy start key is pressed all the way (strictly speaking, until the paper feeding operation starts), unstable detection data when the platen cover is opened and closed can be eliminated. In addition, in order to determine whether the signal from the light receiving sensor of the reflective optical sensor is truly due to reflection from the document or due to ambient light, the light emitting side is turned on and off to check for the presence of ambient light. to prevent false detection due to ambient light.

Embodiment FIG. 1 is a perspective view of a copying machine showing an embodiment of the present invention. On the upper surface of the copying machine main body 1, a document table (platen) 2 made of a transparent glass plate is provided in a defined manner. At the left end of the document table 2, there is a stopper 4 for aligning the document 3.
is provided, and the operator sets the original 3 so that the center of the original 3 is aligned with the center mark 5 at the center of the stopper 4. A platen cover 6 is attached to the upper part of the document table 2 by a hinge at its end so that it can be opened and closed. Inside the platen cover 6 is a sensor S N1. for detecting the document size. S N2. S N3. SN4°SN5 are provided.

Cassettes 7 and 8 for setting copy sheets are removably attached to the side of the copying machine body 1, and one of them can be selected by operating the keys on the operation panel 9H. In addition, automatic document size detection described below also allows
A cassette containing paper of the same size as the original is automatically selected.

FIGS. 2(a) and 2(b) are a sectional view and a perspective view of a sensor provided in the platen cover 6. FIG.

Note that this figure is upside down from FIG. 1. The sensor is a light emitting diode 11 and a light receiving phototransistor 1
It can be configured from 2. The sensor cover 10 is provided with holes 11a and 12a for light emission and light reception, respectively, and detects the reflected light from the original through the white translucent film 6a attached to the lower surface of the platen cover 6. Detect. The white translucent film 6a is necessary to prevent a portion of the sensor from being copied black. The sensor is connected to a detection circuit by a lead wire 13.

FIG. 3 shows the distribution of sensors when the platen cover 6 is viewed from the top. Sensors SNI to SN5 are installed in the platen cover 6 at the positions shown with the holes 11a and 12a facing downward, respectively. It's embedded. When the operator places a document on the document table 2 and closes the platen cover 6, sensors SN1 to SN5 on the document respond depending on the yX document size, so W and the document size are detected by the combination. be able to.

FIG. 4 is a block diagram of the control section of the main body of the copying machine. The copying machine is controlled by a microcomputer system including a CPU 14. This microcomputer
The system includes a ROM 15 connected to this CPU 14 for storing control blocks, etc.
A RAM 16 and a CPU 14 are provided for temporarily storing data during control by the main unit 14, and have areas for various flags necessary for control. A sensor input from the document size detection circuit 18 is connected to the input port of the l1017, and a switching signal for controlling the detection circuit 18 is output from the output port. In addition, ROM 15 stores sensor manual data corresponding to each manuscript size.
;I is used to detect the document size.

FIG. 5 is a circuit diagram showing details of the detection circuit 18. The outputs of sensors SN1 to SN5 are each output to comparator 2.
2.23 (the circuits of SN 3 to SN5 are omitted because they are the same as the circuit of SN2), and the comparator 22.23 is connected depending on whether it is higher or lower than the reference voltage (approximately 2.5 V) determined by the resistor 24.25. The output of each becomes "H" or 'L', and T is passed through l1017.

It is taken into the CPU 14. Here, sensor SN1~
When no light enters through the light-receiving hole 12a of SN5, the light-receiving element 26 is in a cut-off state, so the input to the comparator 22.23 becomes approximately 5V, and the sensor power becomes H11. - When the tip of the force is applied, the light receiving element becomes conductive depending on the strength of the force, so the resistance 27.
The input terminals of the Kumpparators 22 and 23 are lowered due to the partial voltage with 28, and when a certain amount of strong light enters, the voltage drops below the reference voltage, and the sensor input voltage is "L".
” is obtained. The variable resistor 27 is for adjusting the sensitivity of the sensor. That is, the resistor 27.28
If the resistance value is large, the partial pressure value with respect to the light-receiving element 26 will be small even for a small amount of light, so that "L" can be obtained as the sensor power, and the sensitivity will be increased.

Moreover, if the resistance value of the resistors 27 and 28 is small, the sensitivity decreases conversely.

When the switching signal output from l1017 is "L", the output voltage of the comparator 19 is "L", so the transistor 21 is turned on, and the sensitivity of the sensor SNI is determined by the resistor 27.28, so the sensor SNI~ S
The sensitivity of N5 will be the same. Further, since the transistor 20 is turned on, the light emitting element 29 is driven. That is, at this time, the document is in a state where it can be detected.

On the other hand, when the switching signal outputted from the 11017 is "H", the output voltage of the damper 19 becomes "H" and the transistor 20 is turned off, so the light emitting element 29 is not driven, and the transistor 21 is also turned off. , the sensitivity of the sensor SNI is determined by the resistors 27, 28, and 30. That is, the sensitivity is higher than in the above-mentioned state. At this time, the light entering the sensor passes through the light emitting element 29.
Since the light is not driven, the light is not reflected from the document but comes from outside. Since this light is weaker than the light reflected from the original in a normal state, only the sensor SN1, which has a sensitivity of -F, detects it. Platen cover 6
If the platen cover is completely closed, this external light will be almost zero, so the sensor power of the sensor SNI will be "H", and it can be confirmed that the platen cover is closed. This confirmation is necessary to avoid false detection of the document size.

FIG. 6 is a flowchart showing the operation of detecting document size. When starting document size detection, first, in step S1, the switching signal is set to "L" to put the detection circuit in the normal document detection state.Next, in step S2, the sensor SN3 or SN4 is set to "L".
Wait for "L" to become "L" (one of them is always turned on when paper of a predetermined size is placed.) When the document 3 is correctly set on the document table 2 and the platen cover 6 is closed, the sensor SN3 Alternatively, since one or both of SN4 is always turned on, this can be detected. The judgment in step S2 is YES
In this case, the process advances to step S3, and the sensor manual pattern and the document size data stored in the ROM 15 are
Determine if there is a match 0 If there is no matching document size, the situation may be that the document is not set correctly or the platen cover is not yet closed 70 minutes, so return to step S2. and try again. If there is a matching document size, proceed to step S4,
The switching signal is set to 'H' to set the external light detection state.Then, in step S5, it is determined whether the sensor SNI is off, and if NO, return to step S1, and if YES, proceed to step S6. , thereby step S2
．． Even if erroneous detection occurs due to relatively strong external light in S3, erroneous judgment can be avoided. Then, in step S6, a cassette containing sheets of paper having the same size as the detected document size is selected.

However, if there is no matching paper, a message is displayed on the display section of the operation panel 9 to inform you of the detected document size. Then, in step S7, the switching signal is set to "L" to set the normal document detection state, and in step S8, the sensor manually detects the document size. See if there is a change in the state. If there is a change, the process returns to step S2 and starts over again. This serves as a trigger for detecting that the platen cover 6 has been opened. Furthermore, since the sensor force is unstable when closing the platen cover 6, even if the document size is incorrectly detected, it can be corrected by starting over from the beginning.

If there is no change in the sensor force, the process advances to step S9, and it is determined whether the timing to start feeding paper from the cassette 7.8 has arrived. If the determination in step S9 is NO, the process returns to step S8, and if YES, the document size detection is ended. As a result, even after the operator operates the operation panel 9 to start copying, if the platen cover 6 is closed before starting paper feeding, the paper will be automatically selected.

(G) In the invention, the optical document detection means continues to detect the document size after the platen cover is closed on the platen until the paper feeding means starts operating. Even if the platen cover is not completely closed over the platen at first, if it is completely closed before the paper feeding means operates, the original size will not be detected incorrectly.

Therefore, it is possible to avoid false detection in an unstable state, which is likely to occur during opening/closing of the platen cover or in the case of a thick original. Furthermore, it becomes possible to prevent false detection due to external light, etc., and it becomes possible to detect the document size more reliably and stably than ever before.

Therefore, automatic selection of copy paper and automatic selection of magnification by more stable automatic detection of document size becomes possible, and a copying machine or the like with fewer copy mistakes can be realized.

[Brief explanation of the drawing]

The drawings all show an apparatus that embodies the present invention; Fig. 1 is a perspective view of a copying machine showing an embodiment, Fig. 2 is a schematic diagram of a sensor provided in the platen cover, and Fig. 3 is a view of the platen cover from above. The layout of the sensor as seen, Figure 4 is a block diagram of the control section of the copying machine body, Figure 5 is a detailed diagram of the detection circuit,
FIG. 6 is a flowchart showing the operation of document size detection. 1... Copying machine main body, 2... Document table (platen), 3
. . . Original, 6. Platen cover, 10. Sensor cover, 11.29. Light emitting diode, 12.
26...Phototransistor, 14...CPU, 1
5...ROM, 16...RAM, 17...Ilo
, 18... Original size detection circuit, 19° 22, 23.
··comparator.

Claims (1)

[Claims] 1. A platen on which a document is placed, a platen cover mounted on the platen so as to be openable and closable, an optical document detection means provided on the platen cover, and a plurality of recording paper storage units. and a paper feeding means for feeding paper of a size corresponding to the original size detected by the optical original detecting means, wherein the optical original detecting means has a platen cover on the platen. 1. A method for automatically detecting a document size, comprising: continuing to detect the document size after starting a closing operation of the document feeder until the paper feeding means starts operating.