JPH01265244A - Detecting method for closed state of platen cover - Google Patents

Abstract

PURPOSE:To prevent maldetection due to an unstable condition and disturbance light and to reduce miscopies by detecting whether a platen cover is closed or not before an optical original detecting means detects an original. CONSTITUTION:Sensors SN1-SN5 detecting original size are provided inside the platen cover 6, and comprise an original size detecting circuit 18. When a switching signal from an I/O 17 is 'H', an output from a comparator 19 rises to 'H', a transistor 20 is turned off, and a light emitting element 29 is not driven. A transistor 21 is also turned off, and the sensitivity of the sensor SN1 is determined by resistances 27, 28 and 30. This determination means that the sensitivity goes up, compared to a case where the sensitivity is determined by the resistances 27 and 28 when the switching signal from the I/O 17 is 'L', and only the sensor SN1 attains this condition. When the platen cover 6 is completely closed, outside light amounts to zero, and the input of the sensor SN1 goes up to 'H', whereby an operator can recognize the complete closing of the cover.

Description

DETAILED DESCRIPTION OF THE INVENTION B) Field of Industrial Application The present invention relates to a method for detecting a platen cover provided in a single-volume reading means such as a copying machine or a factor (IJ).

(B) Conventional technology As a method for detecting the original size of a conventional copying machine, a method is used in which a reflective optical sensor is built into the platen cover to detect the reflection on the back side of the 1st manuscript (Japanese Unexamined Patent Publication No. 73623/1982). (see Japanese Patent Laid-Open No. 50-11242), a light-receiving sensor is placed inside the platen cover, a light-emitting unit is placed on the bottom surface of the document, and a scanning detection method utilizes the light shielding of the 1-port document (see Japanese Patent Laid-Open No. 50-11242). Many detection means are known, such as a method of arranging a type optical sensor and detecting reflection on the surface of the document (see Japanese Patent Laid-Open No. 5e-78849).

By the way, if the single-page document size detection method uses a reflective optical sensor built into the platen cover, if the platen cover is closed and the reflective sensor is facing the back side of the document, The original size cannot be detected. Therefore, conventionally, an opening/closing detection switch is provided which is turned on/off by opening/closing the platen cover. However, with thick originals, the open/close detection switch may not operate accurately, and the structure required to mount the open/close switch and its actuator is complicated.

Furthermore, when there is strong ambient light, there is a problem that the reflective optical sensor responds regardless of the reflection of the document and Jfi, resulting in false detection.

(c) Invention tries to solve the problem! ! In addition to removing components with complex structures such as the platen cover opening/closing detection switch and its actuator, we have also removed the reflective type that prevents malfunctions in document detection with thick documents, false detections that occur when opening and closing the platen cover, and the effects of ambient light. To prevent malfunction of an optical sensor and to detect a large manuscript size stably with a simple composition.

B.) Means for Solving the Problems The present invention provides a platen on which an original is placed, a platen cover mounted on the platen so as to be openable and closable, and a plurality of optical originals provided on the platen cover. In the platen cover closure detection method for a platen and a platen cover in which a platen and a platen cover are provided with a detection means, before the optical document collection detection means detects a document, our optical document collection detection means is operated to detect the platen cover. It is characterized by detecting whether or not the cover is closed.

09 action As a trigger signal to start the document size detection operation, only the opening and closing of the platen cover is used. Instead of using a separate open/close switch, a reflective light attached to the platen cover provided for detecting the document size is used. Focusing on the fact that there is a sensor that responds to any document size, the on/off signal of that sensor is used. Furthermore, by repeating the document size detection operation until the copy start key is pressed (strictly speaking, until the paper feeding operation starts), unstable detection data when the platen cover is opened and closed can be eliminated. Yes, in order to determine whether the signal from the light-receiving sensor of the reflective light sensor is truly from the reflection of the original or from ambient light, we turn on and off the light-emitting side and detect the presence or absence of ambient light. to prevent 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. A document table (platen) 2 made of a transparent glass plate is fixedly provided on the upper surface of the copying machine main body 1. 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 so that it can be opened and closed by a hinge at its end.

Inside the platen cover 6, there is a 1 to detect the document size.
7) Sessa-'INI, 1lIN2.8M3.8N4
．． 8N5 75 (provided.

A cassette 7.8 for setting copy paper is removably attached to the side of the copying machine body 1, and by operating the keys on the operation panel 9, it is possible to select either "Busy" or "Juku". In addition, automatic document size detection described below also allows
A cassette containing paper of the same size as the original is automatically selected.

2nd IQ (a) and (b) are a sectional view and a perspective view of a sensor provided in the middle of the platen cover 6. Note that this figure is upside down from FIG. 1. The sensor is composed of a light emitting diode 11 and a light receiving phototransistor 12. 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 document through the white translucent film 6a attached to the bottom surface of the platen cover 6. Detect. A white translucent film 6& 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 arrangement of the sensors when the platen cover 6 is viewed from above. The sensors 8N1 to 8NS are embedded in the platen cover 6 at the positions shown in the figure, with the nine surfaces of the holes 11a and 12a facing downward. When the operator places a document on the document table 2 and closes the platen cover 6, the sensors 8n to 8N5 that are on the document respond depending on the document size, so the document size can be detected by the combination of sensors 8n to 8N5. can.

- Figure 4 is a block diagram of the control section of the main body of the copying machine.

The copier is controlled by a microcomputer system including a CPI)14. This microcomputer system includes a ROM 15 for storing control programs etc. connected to this CPσ14,
Temporarily stores data during control by CPσ14,
and a RAMI that has an area for various flags necessary for control.
(l and CPσ14 are provided with a sixth mechanism 1017 that controls the input and output of the internal equipment of the main body.11017
The sensor input from the document size detection circuit 18 is connected to the input boat, and the detection circuit 18 is connected to the output boat.
A switching signal is output to control the Also, ROM15
Data on sensor manual power corresponding to each document size example is stored in , and is used to detect the document size.

FIG. 5 is a circuit diagram showing details of the detection circuit 18. The outputs of the sensors gNI to Ells are each connected to comparators 22.23 (the circuits of EIN3 to EIN5 are the same as the circuit of YON2, so they are omitted), and the reference voltage (approximately 2.57') determined by the resistor 24.25 higher or lower, the outputs of comparators 22, 23 are respectively mu
m or II L w, and CP through Engineering 1017.
I] 14. Here, sensors 8N1 to 8
When no light enters from the light receiving hole 12a of Ns,
Since the light receiving element 26 has a cut-off width, the input to the comparators 22 and 23 becomes approximately 5V, and the sensor power reaches "H". - When the tip of the force is applied, the light receiving element becomes conductive depending on the strength of the force, so the resistance is 27.2
The input voltage of the comparators 22 and 23 is determined by the partial voltage of
” is obtained. 27 variable resistors are used to adjust the sensitivity of the sensor. In other words, 27.28
If the resistance value of resistor 27.
Conversely, if the resistance value of 28 is small, the sensitivity decreases.

When the switching signal output from the switch 1017 becomes "L", the output voltage of the comparator 19 becomes @L", and the transistor 21 turns on. The sensitivity of the sensor BtJ1 is determined by the resistor 27.28, so the sensor ENl ,
The sensitivity of EIN5 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 output from the l1017 is 1P, the output voltage of the comparator 19 becomes @H'' and the transistor 20 is turned off, so that only the light emitting element 29 is not driven.Then, the transistor 21 is also turned off. , the sensitivity of sensor F3N+ is resistance 27, 28.30
Determined by In other words, the sensitivity is higher than in the above-mentioned state. At this time, the light entering the sensor is transmitted to the light emitting element 2.
9 is not driven, the light is not reflected from the document but enters from outside. Since this light is weaker than the light reflected from the document under normal conditions, only the highly sensitive sensor 8N1 detects it. Platen cover 6
If the platen cover is completely closed, this external light will be almost zero, so the sensor power of sensor 8N1 will be @H", and you can confirm that the platen cover is closed. This confirmation can be done by checking the document size. This is necessary to avoid false positives.

FIG. 6 is a flowchart showing the operation of document size detection. When original size detection is started, the switching signal is first set to 12 in step 81 to put the detection circuit into a normal original detection state. Next, in step 82, wait for the sensor 8N3 or sN4 to become "IIL" (either one is always turned on when paper of a predetermined size is read). The document 3 is set correctly on the document table 2, and the platen cover 6 is closed, either sensor 8 or EIN 4 or both are always turned on, so this can be detected.The judgment in step e2 is YKE
In the case of i, the process proceeds to step e3, and it is determined whether the sensor manual pattern and the document size data stored in the ROM 15 match. If there is no matching document size, the document may not be set correctly or the platen cover may not be closed sufficiently, so return to step day 2 and try again.

If there is a matching document size, the process proceeds to step B4, where the switching signal is set to ``''■'' to enter the external light detection state.

Then, in step 85, it is determined whether the sensor 8N1 is off, and if No, the process returns to step 81 and YES.
If S, the process advances to step s6. This makes it possible to avoid misjudgments even in the case of erroneous detection due to relatively strong external light in step 2.63. And step 8
In step 6, a cassette containing sheets of paper having the same size as the detected original is selected.

However, if there is no matching paper, a display is displayed on the display section of the operation panel 9 informing the detected document size. Thereafter, in step 87, the switching signal is set to "L" to set the normal document detection state, and in step 88, it is checked whether there is any change in the state of the sensor's manual power. If there is a change, return to step 82 and start over. This serves as a trigger for detecting that the platen cover 6 has been opened. Furthermore, since the manual force of the sensor becomes unstable when the platen cover 6 is closed, even if the document size is incorrectly detected, it will be corrected rather than restarting from the beginning.

If there is no change in the sensor force, the process proceeds to step B9, and it is determined whether the timing to start feeding paper from the cassette 7.8 has arrived. If the determination at step 89 is NO, the process returns to step g8, and if the determination is ``Yill'', the original size detection ends. 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) Effects of the Invention According to the present invention, it is possible to omit a switch for detecting the open/closed state of the platen cover, which was conventionally required as a trigger signal for detecting the document size, and when the platen cover is in the middle of opening/closing operation or when the document is thick. It is possible to avoid false detections in unstable conditions, which are likely to occur. 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, it is possible to put into practical use a copying machine or the like that is capable of automatic selection of copy paper and automatic selection of magnification by more stable automatic detection of document size, and with fewer copy errors.

[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. #S3 is a view of the platen cover from above. FIG. 4 is a block diagram of the control section of the main body of the copying machine, FIG. 5 is a detailed diagram of the detection circuit, and FIG. 6 is a flowchart showing the operation of detecting the document size. 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, 18...RAM117...Eng.10
118... Original size detection circuit, 19, 22.23.
・・Combare~ri.

Claims (1)

[Claims] 1. The device includes a platen on which a document is placed, a platen cover that is openably and closably mounted on the platen, and a plurality of optical document detection means provided on the platen cover. In the platen cover closure detection method for the platen and platen cover, before detecting the document by the optical document detection means,
A method for detecting platen cover closure, comprising operating the optical document detection means to detect whether or not the platen cover is closed.