JP2915923B2 - Document size detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention automatically adjusts the size of a document placed on a transparent platen such as an image forming apparatus such as a copying machine, a facsimile apparatus, and an image scanner. And a document size detecting device for detecting the original size.

[Conventional technology]

A transparent platen and a document holding member that opens and closes between a closed position covering the upper surface and an open position to open the platen, and reads an image of a document placed on the platen and pressed by the document holding member. In an exposure apparatus such as an electrophotographic copying machine or a digital copying machine, conventionally, the size of a document placed on its platen (contact glass) is detected, and transfer paper of a size suitable for the size is detected. Is automatically selected and fed.

For example, Japanese Patent Application Laid-Open
As described in JP-A-56-78849, a light emitting unit and a plurality of light receiving units are provided at the lower part of the document table, and when the document pressing member is closed, a micro switch operates to light the light emitting unit, In some cases, the size of a document is determined based on a combination of the light receiving states of a plurality of light receiving units, so that the influence of light reflected from a document pressing member is eliminated.

Before copying a document placed on the platen, the light receiving unit fixed to the light source unit is scanned together with the light source unit to detect the document size. There is also known an apparatus in which a light emitting unit is provided separately from a light receiving unit, and the size of a document is detected using transmitted light.

[Problems to be solved by the invention]

However, among such conventional document size detection devices, those which detect the document size when closing the document pressing member using reflected light from the document,
Documents that detect transmitted document size using transmitted light, such as when copying a thick book or double-page spread, cannot operate on the document size when the document holding member is fully opened and cannot be detected. There was a problem that if you made a copy without noticing it, it would be copied on the paper of the wrong size specified last time.

If the size of the original is detected by optically scanning the original before copying, the above problem can be alleviated. However, it is difficult to determine the light reflected by the original and the original pressing member, and time is required for optical scanning. In particular, when one copy is made for one document, the copying speed is significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a document size detecting device capable of reliably detecting a document size with a simple structure without lowering the processing speed. .

[Means for solving the problem]

In order to achieve the above object, the present invention comprises a transparent document table and a document pressing member which opens and closes between a closed position covering the upper surface thereof and an open position which opens the document table. In an apparatus for reading or exposing an image of a document pressed by a member, the first invention is, as shown by a functional block diagram in FIG. 1, a plurality of documents necessary for discriminating at least a document size on a document table. A document detecting means 1 comprising a light emitting section for irradiating a detection point from the back side of the document table, a plurality of light receiving sections for respectively receiving reflected lights from the plurality of detection points, and an open / close position of a document pressing member. A document pressing member open / close detecting means 2 for detecting, and in a state where the document pressing member open / close detecting means 2 detects an open position of the document pressing member, a light receiving amount of each light receiving portion by the document detecting means 1 changes for a predetermined time. In the event that the First document size storage means 3 for discriminating and storing the size of a document placed on a document table based on a combination of detection points determined to have a document based on the amount of light received by the light unit; When the open / close detection means 2 detects the closed position of the document pressing member, the document placed on the document table by a combination of detection points determined to have a document based on the amount of light received by each light receiving portion of the document detection means 1 A second document size storage means 4 for determining and storing the size of the document;
A document for selecting one of the document sizes stored in the first and second document size storage means 3 and 4 according to the open / close position of the document pressing member detected by the document pressing member open / close detecting means 2 The present invention provides a document size detecting device including a size selecting means 5.

In the second invention, as shown in the functional block diagram of FIG. 2, instead of the first and second document size storage means 3 and 4 in the first invention shown in FIG. A first and a second document storing the document presence / absence data at each detection point determined from the amount of light received by each light receiving unit of the document detection unit 1 in a state where the detection unit 2 detects the open position and the closed position of the document pressing member. The original presence / absence data storage means 6 and 7 are replaced with the original size selection means 5 in the first invention. One of the document presence data stored in the first and second document presence data storage means is selected according to the open / close position of the holding member, and it is determined from the selected document presence data that there is a document. Combination of detection points Size determining means 8 for determining the size of a document placed on a platen
Are provided respectively.

(Operation)

According to the document size detecting device thus configured, the amount of light received by each light receiving portion of the document detecting means 1 is equal to the amount of light reflected from the document at the light receiving portion with respect to the detection point of the portion where the document is placed on the document table. In the light receiving part for the detection point of the part where the original is not placed on the platen, the light from the light emitting part is not reflected except for the position where the original pressing member is almost fully closed. Do not enter the part.

For this reason, in FIG. 1, when the document pressing member is at the open position and when the document pressing member is at the closed position, the presence or absence of the document at each detection point is determined based on the amount of light received by each light receiving portion of the document detecting means 1. The size of the original placed on the original platen is determined from the combination of the detection points determined to have, and the result is stored in the first and second original size storage units 3 and 4, respectively.

When the apparatus for reading or exposing the image is started by the document size selecting means 5, the first and second originals are set in accordance with the open / close position of the original pressing member detected by the original pressing member open / close detecting means 2. One of the document sizes stored in the size storage means 3 and 4 is selected.

Similarly, in FIG. 2, when the document pressing member is at the open position and when the document pressing member is at the closed position, the document detecting means 1 is provided.
The presence or absence of a document at each detection point is determined based on the amount of light received by each of the light receiving sections, and stored in the first and second document presence / absence data storage means 6 and 7, respectively.

Then, when the apparatus for reading or exposing an image is started by the document size determining means 8, the first and second originals are set in accordance with the open / close position of the original pressing member detected by the original pressing member open / close detecting means 2. One of the document presence data stored in the presence / absence data storage means 6 and 7 is selected, and the document is placed on the document table by a combination of detection points determined to have a document based on the selected document presence data. The determined document size is determined.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 3 is an explanatory diagram showing a specific configuration example of the document detecting means 1 in one embodiment of the present invention.

Below a plurality of detection points P (only one of them is shown in FIG. 3) on a transparent document table (contact glass) 10 provided on the upper part of a copying machine (not shown), an LED 12a as a light emitting part is provided. A reflection type photosensor (hereinafter, also simply referred to as “photosensor”) 12 including a phototransistor 12b as a light receiving unit is provided.

The LED 12a is turned on and off by a switch 11 composed of a transistor, and the phototransistor 12b emits light from the light emitting LED 12a reflected by a document 13 placed on a document table 10.

If the signal input to the switch 11 via the I / O port 32 (FIG. 7) described later is "L", the switch 11 is off, and the LED 12a does not emit light. If the signal is "H", the switch is turned off. 11 is turned on, current from the power supply Vcc flows through the resistor R ₁ to the through connexion LED12a emit it.

The phototransistor 12b is connected to the LED 12a at the detection point P.
Detecting reflected light of the light from, the photocurrent is converted into by connexion voltage to the resistor R _2, and outputs as a detection signal to the Figure 7 of the A / D converter (ADC) 31.

When the document 13 is at the detection point P, the detection signal is at a high level,
When the document 13 is not present at the detection point P, the detection signal is almost zero because there is no reflected light (when the document holding plate 14 is in the fully opened or half-opened state).

Although FIG. 3 shows an example in which the reflection type photo sensor in which the light emitting unit and the light emitting unit are integrally formed is used, the LED and the photo transistor may be separately arranged, or the photo transistor may be arranged separately. Only a light receiving unit such as a light source or a photodiode is arranged so as to individually receive the reflected light from each detection point P, and one or a required number of lamps are used as the light emitting unit so as to illuminate all the detection points. And
A light source such as an LED may be provided.

FIG. 4 is a plan view showing an example of the arrangement of seven detection points to (corresponding to the detection point P in FIG. 3) on the A3 size document table 10, which is viewed from the operator facing the copying machine. The direction (vertical, horizontal) of the transfer paper is shown in the direction viewed from the paper supply side (right side) in the paper supply direction indicated by the arrow.

The photo sensor 12 shown in FIG. 3 for each of the detection points 1 to 3 moves the surface of the document table 10 to the paper standards A3, B4, A4, B5, A4, A5, B5, A5. When the document is classified into positions where various types of documents are placed, they are arranged at positions that do not interfere with movable members such as a lens and a scanner mirror so that the size of each document can be determined.

In this way, the size of the document 13 can be determined based on the combination of the presence or absence of the document at each detection point as shown in the following table. In the following table, “1” indicates that there is a manuscript,
"0" indicates that there is no original.

FIG. 5 is a schematic configuration diagram showing an example of a structure in which the photosensors 12 are arranged at the detection points 1 to 4 (FIG. 4), respectively.

Located at the bottom of the platen 10, the lamp 20 and the reflector, the scanning light source unit 21 composed of a Mohikari preventing cover or the like, the first mirror M ₁ and the integral in such connexion, the document 13 on the platen 10 drawing Light scanning is performed at a constant speed from left to right on the top.

The second and third mirrors M ₂ and M ₃ are integrally formed so as to be orthogonal to each other, synchronized with the mirror M ₁ integrated with the scanning light source unit 21, and from the left at half the scanning speed. Move right.

The imaging lens system including the magnifying lens L ₁ , the equal-magnification lens L _2, and the reducing lens L ₃ is configured such that an image of a document is formed on the photosensitive drum 22 in accordance with a copying magnification specified by an operator.
The position is set.

The illuminated portions of the original 13 (size A4 length) illuminated by the scanning light source unit 21 are reflected by the mirrors M ₁ , M ₂ , and M ₃ , respectively, and enter the magnifying lens L ₁ .

The optical path length from the original to the imaging lens system is constant and does not change with scanning.

The light beams transmitted through the imaging lens systems L ₁ , L ₂ , L ₃ are reflected by the fixed fourth, fifth, and sixth mirrors M ₄ , M ₅ , M ₆ , respectively, and are charged in advance and indicated by arrows. An image is formed on the photosensitive drum 22 rotating in the direction to form an electrostatic latent image.

On the upper surface of the outer panel 23 of the copying machine main body,
Document positioning scale 24 and hinge 17 described later (FIG. 6)
Original document holding plate 14 (half-open state)
Is provided.

On the inner surface of the exterior panel 23, a base plate 25 on which optical components such as mirrors and lenses are mounted in the middle stage, and a lens cover 26 are provided.

Photo sensors 12 are provided immediately below each of the detection points to (FIG. 4). However, since all the detection points are within the range of the maximum size (A3), the photo sensors 12 When a mirror M ₁ and the integral of the scanning light source unit 21
Alternatively, it collides when the integrated mirrors M ₂ and M ₃ move.

It was but connexion, each photo sensor 12 is away from the platen 10 is provided below the operating range of the lower or mirror M _2, M ₃ than the operating range of the scanning light source unit 21 including the mirror M _1.

For example, as shown in FIG. 5, the photo sensors 12A to 12D corresponding to the detection points 1 to 12 are mounted on the upper surface of the lens cover 26, and the photo sensors 12G corresponding to the detection points are mounted on the upper surface of the base plate 25, respectively. 12G is manuscript 13
The one with the working distance according to the distance from is used.

In the example shown in the figure, since the size of the document 13 is A4 length, the photo sensors 12A and 12B have no reflected light, and the photo sensors 12C, 12D and 12G and the photo sensors (12E and 1E) not shown.
2F) detects reflected light.

FIG. 6 is an explanatory diagram showing a specific configuration example of the document pressing member open / close detecting means 2.

One end of a document holding plate 14 is rotatably attached to a hinge 17 at one end of an exterior panel 23 of the copying machine on which the document table 10 is provided.

An opening / closing instruction plate 27 is provided protruding from the rotation end of the document holding plate 14, that is, the lower surface near the hinge 17, while the document holding member via the bracket 18 is provided on the lower surface near the hinge 17 of the exterior panel 23. A switch 28 serving as the open / close detecting means 2 is attached.

The switch 28 is formed of, for example, a photoelectric switch using a transmission type photo sensor. The switch 28 is turned on when the open / close instruction plate 27 shields the transmitted light when the document pressing plate 14 is in the half-open position.

That is, when the document holding plate 14 is fully opened, the switch 28 is off, and when the document holding plate 14 starts to be closed and reaches a half-open position (light reflected by the document holding plate is not yet received), the switch 28 is turned on. It remains on even when fully closed.

FIG. 7 is a block diagram showing a configuration example of the control unit of this embodiment.

A CPU 30 composed of a microcomputer is connected to each phototransistor (PTR) 12b of the seven reflection type photosensors 12 via an A / D converter (ADC) 31 and to the photosensor 12 via an I / O port 32 and a switch 11. Each LED 12a is connected to each other.

The I / O port 32 is connected to a switch 28 for detecting whether the document holding plate 14 is open or closed.

Further, the CPU 30 has a ROM 33 storing programs and constant data, and a RAM 34 which is also the first and second document size storage means 3 and 4 or the first and second document presence data storage means 6 and 7.
And are connected.

The CPU 30 detects whether or not a document exists at each detection point at a predetermined interval, for example, every 10 ms.

That is, the CPU 30 turns on the LED 12a via the I / O port 32 and the switch 11, and irradiates the original 13 on the original platen 10,
The light reflected by the original 13 enters the phototransistor 12b below it.

The level of the detection signal output by the phototransistor 12b in accordance with the amount of received light is converted into a digital value by the A / D converter 31 and input to the CPU 30, and when the document has a value equal to or greater than the value corresponding to the threshold of the amount of received light, that is, If it is less than "1", that is, if there is no original, it is binarized to "0".

When the detection signal is converted into a digital signal and binarized, the LED 12a is turned off.

The CPU 30 edits the binarized data into 7-bit document presence / absence data arranged in the order of the detection points and thereafter, and then determines the document presence / absence determination data and each of the data as shown in the preceding table stored in the ROM 33. By sequentially comparing with the list of data corresponding to the original size, it is determined that the original size corresponds to the matched data, and if the switch 28 is off (the original pressing plate 14 is open), the RAM 34 If the switch 28 is on in the first document size area, the second
Are stored in the document size areas of

When the copying machine is started by the operator pressing a start button (not shown), the document size selecting means 5
The CPU 30 (FIG. 1) detects the start signal and selects one of the first and second document sizes according to the on / off state of the switch 28.

That is, if the switch 28 is off (the document holding plate 14 is open), the first document size is selected, and if the switch 28 is on (closed), the second document size is selected and output as document size data.

Hereinafter, the operation of this embodiment will be specifically described with reference to the flowcharts shown in FIGS. 8 to 11.

FIG. 8 is a flowchart showing an example of a subroutine "size detection" called by the main routine to detect a document size. FIGS. 9 and 10 are used by the subroutine "size detection" shown in FIG. It is a flowchart which shows each subroutine.

In the subroutine "presence / absence determination" shown in FIG. 9, the detection signal output from the phototransistor 12a at a certain detection point is A / D
The data is converted into a digital value by the converter 31 and input, and the detection result binarized based on whether the value is equal to or greater than a predetermined threshold value is stored in a buffer corresponding to the detection point, and
Is completed, the process returns to editing the 7-bit document presence / absence data arranged in that order.

In the subroutine "size determination" shown in FIG. 10, the document presence / absence data is sequentially compared with a list of data corresponding to each document size stored in the ROM 33 as shown in the preceding table. If there is no matching data, a size error or a special size is determined, and the process returns.

Returning to FIG. 8, when jumping from the main routine to the subroutine "size detection" shown in FIG. 8, first, the subroutine "presence / absence determination" (FIG. 9) is executed to execute new document presence / absence data (hereinafter "new data"). After that, it is determined whether or not the new data is “0”.

New data is "0", that is, all detection points are "0"
If the original is not set, the process immediately returns to the main routine.

If the new data is not "0", that is, if any of the detection points is "1" (there is a document), it is determined whether or not the switch 28 (SW) is off. Proceed to routine 2.

If the process proceeds to Routine 1 with the SW off (the document holding plate 14 is open),
After the flag is turned off (reset), the previous document presence / absence data (hereinafter referred to as "previous data") previously stored in the RAM 34 is compared with the new data, and if not the same, the new data is stored in the area of the previous data. The data is stored (previous data is updated), a predetermined value, for example, 10 to 20, is set in the counter, and the process returns.

If the new data is the same as the previous data, the counter is decremented by one. If the counter is not 0, the return is performed.
100ms to 200ms) If the document presence data has not changed,
The subroutine "size determination" (FIG. 10) is executed to determine the document size, the result is stored in the first document size area as the first document size, and the routine returns.

If a size error occurs, the first document size may not be stored as the first document size, and the previous first document size may remain.

As described above, since the size is not determined unless the document presence data is stable for a predetermined time, the document holding plate
If 14 is open (switch 28 is off), changing new data during document set operation or size errors due to temporary placement of documents or other items are ignored, and new data is Since the document size determined because it does not change for a predetermined time is updated each time the state changes, the latest stable document size is always the first stable document size until the document holding plate 14 is half-opened (the switch 28 is turned on). Is stored as the original size.

When the switch 28 (SW) is turned on and the routine proceeds to the routine 2, it is determined whether or not the flag is off.

If it is the first time, the flag is off, so after turning on the flag, the subroutine "size determination" (No.
Figure 10) to determine the original size, and
The document size is stored in the second document size area and the process returns.

From the second time on, both the SW and the flag are on, so the routine proceeds to Routine 2 and returns as it is.

Therefore, during the operation of closing the document holding plate 14 from the fully opened state,
If the switch 28 is turned on in the half-open state, the original size is determined only once and stored as the second original size, and is not updated until the switch 28 is turned off.
The presence or absence of a document is detected in a closed state in which the detection point where there is no document detects reflected light from the inner surface of the document holding plate 14, so that the size of the document is not mistaken.

FIG. 11 is a flowchart showing an example of a subroutine “size selection” for selecting a document size when the CPU 30 detects a start signal.

The subroutine "size selection" shown in the figure determines whether or not the start signal is output, and if not, returns to the main routine immediately.

If the start signal is output, switch 28 (SW)
Is off (original presser plate 14 is open) and RA
Of the data stored in the first and second document size areas of M34, the first document size is selected if the switch is off, and the second document size is selected if the switch is on, and the selected document size is selected. Is output as original size data and the routine returns.

As described above, if the document is a normal thin document, the operator presses the start button after closing the document holding plate 14, so that the document holding plate 14 is in a half-open state or less, and the final data based on the last data in which the document does not change. 2 is output.

In the case of a thick original such as a thick book, the operator cannot determine the second original size because the operator presses the start button with the original holding plate 14 fully opened, but at that time, the final data based on the open state is used. Since the first document size is selected, correct document size data is always output.

As above, the example in which the first invention is applied to the copying machine has been described.

However, when setting an original on the platen,
There is no need to set the original perfectly to the localization value from the beginning. First, place the original on the platen, slide the original by hand, hit the original positioning scale 24 (Fig. 5), and finally follow the original positioning scale. Move the original and adjust to the localization value.

While the document holding plate is fully opened, the first document size is determined when the document presence / absence data does not change for a predetermined period of time. However, when the operator finishes setting the document, it starts immediately. Since I sometimes press the button,
The predetermined time cannot be too long.

Therefore, such a degree of stillness often occurs during the document setting, so that the size is determined each time.In addition, since the position and direction of the document are varied and the size error increases during the setting, the number of error processing times increases. And wasteful processing time may increase.

The second invention eliminates such useless processing time.
In order to enhance the efficiency of the CPU, the first and second original presence / absence data areas of the RAM 34 serving as the first and second original presence / absence data storage means 6 and 7 without determining the original size each time without changing the original presence / absence data. And the CPU 3 serving as the document size determining means 8
0 (FIG. 7) detects the start signal, selects the first and second document presence / absence data, and selects the selected document presence / absence data.
It is called from the RAM 34 to determine the size.

Specifically, (1) In the subroutine "size detection" shown in FIG. 8, "size discrimination" in the routine 1 and the routine 2 is deleted, and "the first and second document sizes" in the next step are deleted. Is replaced with "first and second document presence / absence data storage".

(2) In the subroutine "size selection" shown in FIG. 11, "select the first and second document sizes" in the next step of the SW off determination are respectively "select the first and second document presence data". Then, "size discrimination" is inserted between the point where the two routes merge and "output document size data" in the next step, and the subroutine name "size selection" is changed to "size determination".

If so, the size determination is performed only once per document, so that the processing time is further reduced and the efficiency of the CPU is increased.

Further, since the document size is determined from the document presence / absence data in which the position and direction of the document are determined, no size error occurs because the position and direction of the document are not determined, such as data in a set.

Moreover, the effect of the first invention is the same in the second invention.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a document size detection device that reliably detects a document size without reducing the processing speed with a simple structure.

[Brief description of the drawings]

1 and 2 are block diagrams showing the functional configuration of the first and second embodiments of the present invention, respectively. FIG. 3 is an explanatory diagram showing an example of the configuration of the original detecting means, and FIG. FIG. 5 is a plan view showing an example of the arrangement of detection points on the document table, FIG. 5 is a schematic diagram showing an example of the arrangement of the reflection type photo sensor, and FIG. FIG. 7 is a block diagram showing an example of the configuration of the control unit, and FIGS. 8 to 11 are flow charts showing the operation of the embodiment of the first invention. 1 Document detecting means 2 Document pressing member open / close detecting means 3 First document size storing means 4 Second document size storing means 5 Document size selecting means 6 First document presence / absence Data storage means 7 Second document presence / absence data storage means 8 Document size determination means 10 Document table (contact glass) 12 Reflection type photo sensor 12a LED (light emitting unit) 12b Photo transistor ( Light-receiving part) 13 Document 14 Document holding plate (Document holding member) 28 Switch

Claims (2)

(57) [Claims] An original holding member which is opened and closed between a transparent position and a closed position for covering the upper surface thereof and an open position for opening the upper surface, and is placed on the original plate and pressed by the original pressing member. In an apparatus that reads or exposes an image of a document, a light emitting unit that irradiates a plurality of detection points on the document table at least necessary for determining a document size from the back side of the document table,
Document detecting means comprising a plurality of light receiving portions for respectively receiving the reflected lights from the plurality of detection points; document pressing member open / close detecting means for detecting the open / close position of the document pressing member; When the light receiving amount of each light receiving unit by the document detecting unit does not change for a predetermined time while the unit detects the open position of the document pressing member, it is determined that there is a document from the light receiving amount of each light receiving unit. First document size storage means for determining and storing the size of the document placed on the document table based on the combination of the detected points, and the document pressing member opening / closing detecting means for determining the closed position of the document pressing member. The size of a document placed on the platen is determined and stored based on a combination of detection points determined to have a document based on the amount of light received by each light receiving unit by the document detection means when the document is detected. Manuscript When the apparatus for reading or exposing the image is started, the first and second document sizes according to the open / close position of the document pressing member detected by the document pressing member open / close detecting means. An original size detecting device, comprising: an original size selecting unit for selecting any one of the original sizes stored in the storage unit. And a document holding member that opens and closes between a transparent position and a closed position that covers the upper surface of the platen, and an open position that opens. The document is placed on the platen and pressed by the document pressing member. In an apparatus that reads or exposes an image of a document, a light emitting unit that irradiates a plurality of detection points on the document table at least necessary for determining a document size from the back side of the document table,
Document detecting means comprising a plurality of light receiving portions for respectively receiving the reflected lights from the plurality of detection points; document pressing member open / close detecting means for detecting the open / close position of the document pressing member; When the light receiving amount of each light receiving unit by the document detecting means does not change for a predetermined time in a state where the means detects the opening position of the document pressing member, the document at each detection point is detected from the light receiving amount of each light receiving unit. First document presence / absence data storage means for determining and storing presence / absence, and each detection point based on the amount of light received by each of the light receiving sections by the document detection means when the document holding member open / close detection means detects the closed position of the document holding member. A second document presence / absence data storage means for determining and storing the presence / absence of a document, and a document holding member open / close detection means for detecting when the apparatus for reading or exposing the image is started. One of the document presence data stored in the first and second document presence data storage means in accordance with the opening / closing position of the document pressing member, and a document is present from the selected document presence data. And a document size determining means for determining a size of the document placed on the document table based on a combination of the detection points determined as above.