JPH073555B2 - Document size detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a document size detection device in a copying machine or the like.

2. Description of the Related Art Generally, in a copying machine, the copy magnification is set according to the size of the original, so that the size of the original is automatically detected. As the original size detection method, a method of detecting reflected light from the original, a method of detecting light blocking by the original, a method of detecting by cutting off the conductive circuit between the original table and the original cover by placing the original, etc. ,
There are various methods.

Among these, as a method for determining the original size by detecting the reflected light from the original, as shown in, for example, Japanese Patent Laid-Open No. 53-110837, unevenness is formed on the original cover, and there is a portion where the original exists. In some cases, the detection is performed by making the optical path of the reflected light different between the non-covered portion, that is, the original cover portion. Further, optical sensors are provided on the lower surface of the document table at a position that does not affect the image formation and in the vicinity of the reference line of the document set, in the width direction of the document as many as the size types.
There is a method of detecting the original size by turning on the original illumination lamp and turning on the optical sensor that receives the reflected light from the original, but turning off the optical sensor in the part where the original does not exist.

However, in the case of the former method, it is necessary to make unevenness on the surface of the original cover. In the case of the latter method, the number of optical sensors is the same as the number of types of document size, and even if the size is different, such as A3 portrait document and A4 landscape document, the same width dimension It may not be possible to judge. From this point, it is possible to determine a minute difference in the document length or width by increasing the number of optical sensors, but the mechanism for positioning each optical sensor becomes complicated and adjustment is troublesome. Therefore, the cost becomes high. And
It is conceivable to mount an optical sensor on the original exposure scanner, but even in this case, the same number of optical sensors are required as the original size, and the same drawbacks are still present. or,
The number of connecting lines between these optical sensors and the control device fixed to the main body of the copying machine is also increased.

Even in the case where a plurality of optical sensors are provided, the original may be placed in a set state, that is, in an inclined state with respect to the reference position, or the original may be displaced due to wind pressure when closing the original pressure plate. There is. When detecting in such a state, a regular ON / OFF signal cannot be obtained from the optical sensor, resulting in incorrect data, and the document size cannot be accurately determined.

The present invention has been made in view of the above points, and can reliably detect the size of a document with a low cost and a simple configuration using a small number of optical sensors, and at the same time, the document may be in a slanted state or misaligned. It is an object of the present invention to provide a document size detecting device capable of surely and accurately determining the size of a document even if it is set in a state or the like.

Structure In order to achieve the above object, the present invention is provided with a detection means having a plurality of optical sensors provided at a predetermined position in the width direction of an original to detect reflected light from the original, and the detection means is provided as described above. A drive unit for scanning relative to the document surface is provided, and one of the optical sensors is used to determine the amount of movement from the device reference position to calculate the amount of movement of the detection position of the detection unit from the device reference position. A document size for determining the document size based on the document width detected by using the other of the optical sensors to determine the document width and the document length converted by the converting unit. In the detection device, the detection devices or the detection timings of the plurality of optical sensors with respect to the document scanning direction are set differently.

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 5. First, a document 1 is set on a contact glass 2 as a document table with a reference position Po as a reference, and is pressed by a document cover 3. Such an original 1 is exposed and scanned by an exposure lamp 5 having a reflecting mirror 4 and a scanner 7 having a first mirror 6, and reflected light from the original 1 is reflected by the first mirror 6 and the second mirror 8 and not shown. An electrostatic latent image is formed by forming an image on the photoconductor through a lens or the like. The scanner 7 is connected to a drive wire 11 which is wound between pulleys 9 and 10, and one surface of the original document is moved to a reference position Po in accordance with a drive pulley 13 rotated by a drive motor 12.
The exposure scanning is performed from the side at a predetermined speed, and then the return operation is performed to the reference position Po side.

Here, in the present embodiment, as shown in FIG. 1, a central reference method is adopted in which the original 1 is set based on the center mark 14 provided at the reference position Po of the contact glass 2.
The type of original used in this embodiment is the A size, and as shown in FIG. 2, the A3 original 1a, A4 portrait original 1b, A4 landscape original 1c, A5 portrait original 1d, and A5 landscape original 1e are 5 sheets. A document 1 of any size of types is set.

Thus, the scanner 7 is equipped with a detection device 15 as a detection means for detecting the document size. The detecting device 15 detects the reflected light from the original 1 using the exposure lamp 5 as a light source, and a slit is provided on a part of the reflecting mirror 4.
4a is formed. The detection device 15 is composed of two optical sensors 15a and 15b such as photodiodes. These optical sensors 15a and 15b are arranged apart from each other in the width direction of the document 1. More specifically, the one optical sensor 15a serves as a first detection unit that detects the document end face in the document exposure scanning direction and generates an end face detection signal.
It is used for determining the amount of movement from the reference position Po, and is arranged on the center reference line, that is, the line of the center mark 14. The other optical sensor 15b serves as a second detection unit that detects the edge of the document in the direction orthogonal to the document exposure scanning direction and generates an edge detection signal, and is used for document width determination. The reflected light from the edge of A3 original 1a or A4 landscape original 1c is received, but A4 portrait original 1b, A5 portrait original 1d and A
5 The document is placed so that it does not receive the reflected light from the landscape original 1e. For these optical sensors 15a and 15b, as shown in FIG. 3, in order to reduce the light receiving range of the reflected light from the manuscript 1 and to improve the size detection accuracy, for example, a light-shielding pipe 16 with a black inner surface is used. And the like, and the range of reflected light that can be received is regulated. Further, these photosensors (photodiodes) 15a and 15b turn on the sensor output when the amount of reflected light received is larger than a predetermined reference light amount, and turn it off when the amount of reflected light is less than the reference light amount. Considering this with or without the original 1, the optical sensor 15
When the outputs of a and 15b are ON, it corresponds to the state where the document 1 is present (the state where the reflected light from the document 1 is received), and when it is OFF, it corresponds to the state where the document 1 is not present. Therefore, the optical sensors 15a, 15
As shown in FIG. 4, b is a sensor circuit 19 in which an OP amplifier 17 to which a resistor R ₁ and a capacitor C are connected, an OP amplifier 18 to which a reference resistor R ₂ and a variable resistor R ₃ are connected are connected in two stages. It is connected to the.

An encoder 20 is connected to the drive motor 12. As a result, the encoder that accompanies the rotation of the drive motor 12
The output pulse number of 20 is counted by a counter (not shown), and from the count number when the output of the optical sensor 15a changes, the reference position of the scanner 7 (and hence the detection device 15)
A conversion unit (not shown) for measuring the movement amount l from Po and converting it to the document length is provided.

With such a configuration, the detection of the document size according to the present embodiment is performed by the preliminary scanning of the scanner 7 prior to the start of the copying operation. That is, the scanner 7 performs preliminary scanning from the reference position Po while turning on the exposure lamp 5. Here, consider a case where, for example, an A4 landscape original 1c is set on the contact glass 2. In this case, at the reference position Po, the optical sensors 15a and 15b both receive the reflected light from the document 1c and the output is turned on. The number of output pulses of the encoder 20 increases as the scanning of the scanner 7 progresses. Then, when the scanner 7 scans to the end of the original 1c, the original 1c disappears and both outputs of the optical sensors 15a and 15b are switched from ON to OFF. At this point, the output of the optical sensor 15a has changed, so the encoder 20
The count of the number of output pulses from is stopped and converted to the movement amount l ₃ of the scanner 7 (detection device 15) from the reference position Po at that time. Based on the value of the movement amount l ₃ , it is temporarily determined that the original 1 set is either the A4 horizontal original 1c or the A5 vertical original 1d. However, at this time, the output of the optical sensor 15b for determining the document width also changes from ON to OFF at the same time. As a result, since the document width is the A4 width, the set document 1 is judged by the document size judging means as the A4 width document 1c.

Further, if the A5 portrait original 1d is set on the contact glass 2, it is determined that either the A4 landscape original 1c or the A5 portrait original 1d at the time when the output of the optical sensor 15a changes from ON to OFF. The determination is similar to the case where the A4 landscape original 1c is set as described above, but when the output of the optical sensor 15a changes, the output of the optical sensor 15b does not change at all. In this case, the combination of the outputs of the sensors 15a and 15b determines that the A5 portrait original 1d is the original size determining unit.

In this way, the A3 document 1 is detected by the combination of the movement amount 1 and the output state of the optical sensor 15b in the scanner 7 (detection device 15) which is converted and calculated by the output change of the optical sensor 15a.
It is possible to determine which size of the original 1 is set, that is, a, A4 portrait original 1b, A4 landscape original 1c, A5 portrait original 1d, A5 landscape original 1e. That is, the optical sensor 15a is turned on according to each document.
When the amount of movement (document length) from the reference position Po at the time of changing from OFF to OFF is l ₁ , l ₂ , l ₃ , l ₄ as shown in FIG.
It is determined as shown in the table below.

As described above, according to this embodiment, the size of the five types of originals 1a to 1e can be determined by using only the two optical sensors 15a and 15b that receive the reflected light from the original 1, and the detection mechanism can be used. It is simplified and the cost is low.

In this embodiment, the case where only the A-size original 1 is described. However, when a B-size original is also used, for example, an optical sensor corresponding to the optical sensor 15b for determining the width of the B-type original. You just need to add one.

By the way, as a return operation method of the scanner 7 at the time of detecting a document size by preliminary scanning of the scanner 7,
Two methods can be adopted. The first method is a method in which even after the document size is detected, scanning is performed for the maximum scanning length determined by the machine, and then a return operation is performed to the reference position Po to wait for a copying operation. Is.
The second method is to detect the document size in the preliminary scan (when the output of the optical sensor 15a changes from ON to OFF).
This is a system in which the scanner 7 is stopped and immediately returned to the reference position Po from that position to put it in a standby state for a copying operation. The first method has the advantage that the operation control system of the scanner 7 can be simplified, and the second method has the advantage that the time required for the prescanning of the scanner 7, that is, the time required for detecting the document size is shortened. . Especially, in the case of a small size original such as an A5 original, the time can be shortened significantly.

Further, in the above description as the document size detection method, the document size is detected when the scanner 7 scans in the direction away from the reference position Po at the time of preliminary scanning, but it may be detected by moving in the opposite direction. Good. That is, the original size is detected when the scanner 7 is in the scanning direction in which it returns from the maximum scanning position to the reference position Po. In the case of this method, by giving a size detection instruction from an operation panel (not shown), the scanner 7 moves to the maximum scanning position and waits for the next instruction. Then, for example, when the next instruction such as the start of copying, the scanner 7 causes the scan position
Once, the scanning is started, and the document size is detected during the movement. Also in this method, the optical sensors 15a, 15b
The position of is the same as in the case of the above explanation, but the operation (O
N, OFF) is the opposite. Since the maximum scanning amount is predetermined by the machine (hence, the output pulse number of the encoder 20 corresponding to the maximum scanning amount is also determined), the movement length of the scanner 7 is subtracted from this maximum scanning amount. By doing so, the document size (length) can be easily calculated.

Therefore, in the above description, the optical sensors 15a and 15b have been described as detecting the original 1 at the same time in the original scanning direction, but in the present embodiment, these optical sensors 15a and 15b are shown in FIGS. As shown in FIG. 3, the delay take-in means is formed at different positions in the original scanning direction. More specifically, the detection device 15 is arranged in an oblique state so that the optical sensor 15b side detects the document 1 ahead of the optical sensor 15a. The effect of such a configuration will be described with reference to FIG. First, the original 1 is at the reference position on the contact glass 2.
Although it should be set correctly with respect to Po, as shown in FIG. 5, in the case where the original 1 is actually placed in a state of being bent obliquely with respect to the reference position Po, or the original pressure plate 3 is placed, The wind pressure at the time of closing may cause the document 1 to be displaced. In such a case, if the optical sensors 15a and 15b are arranged on the same scanning line as shown in FIG. 5 (b), even if the optical sensor 15a for length detection is turned on, the sensor for width detection is turned on. The optical sensor 15b is not turned on, and although the optical sensor 15b has a width to be turned on in the actual document 1, the optical sensor 1b is not turned on.
The document size is determined based on the data that 5a is ON and the optical sensor 15b is OFF, and is recognized as an incorrect size. In this regard, according to the present embodiment, as shown in FIG. 5A, the optical sensor 15b side is arranged ahead of the original scanning direction, and the original 1 is placed in an oblique state as shown in FIG. Even if the original 1 is detected, the optical sensor 15a for detecting the original length
Therefore, the optical sensor 15b for width detection is always located under the document 1 at the timing of turning on and off, so the size of the sensor can be detected accurately by incorporating the data of the optical sensor 15b at the time of detection by the optical sensor 15a. Can be done. Here, the preceding dimension Δl shown in FIG.

Subsequently, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. In this embodiment, as shown in FIG.
Although the optical sensors 15a and 15b are arranged on the same line in the document scanning direction as in the case shown in FIG.
The detection timings of the optical sensors 15a and 15b with respect to the document scanning direction are made different as shown in FIG. First, also in this case, consider the case where the data of the optical sensors 15a and 15b are taken in at the same timing. In the state of the manuscript 1 as shown in FIG. 7, the output state (ON / OFF state) of the optical sensors 15a, 15b causes a time difference of time t ₁ as shown in FIG. ON
ON when data from the optical sensor 15b is captured at the timing
You're not doing it. As a result, the size determination is incorrect. In this respect, in the present embodiment, first, in scanning in the reading direction F (that is, in the forward direction), the scanning of the optical sensor 15b is performed at the sampling timing F after the time t ₂ after the scanning 7 starts from the reference position Po. To do. This time t ₂ is the original 1 detected from the reference position.
The position (time) up to the minimum size of can be set arbitrarily.
Further, in scanning in the reading direction R (that is, in the reverse direction), the sampling timing R with a time difference of t ₃ after ON / OFF detection in which the original 1 is detected by the optical sensor 15a
Thus, the data of the optical sensor 15b is taken in. This time t ₃ can be arbitrarily set as long as it is a position (time) at which the bending of the document 1 can be ignored (although it is necessary to be before the reference position). In this way, the delay capture means is formed by shifting the capture timings of the edge detection signal from the optical sensor 15a (first detection means) and the edge detection signal from the optical sensor 15b (second detection means). , This allows
It is possible to prevent erroneous detection of the document size in either the forward direction or the reverse direction.

Next, a third embodiment of the present invention will be described with reference to FIGS. In this embodiment, only the exposure lamp 5 and the first mirror 6 are mounted on the scanner 7 so that the drive wire 11 is intermittently connected to the drive wire 11 via the first connecting device 21.
A size detecting scanner 22 separate from the scanner 7 is provided by being intermittently connected to the drive wire 11 by a second connecting device 23. The size detection scanner 22 is equipped with the above-mentioned optical sensors 15a and 15b and a lamp 24 separate from the exposure lamp 5 to form a detection device 15. The size detecting scanner 22 is arranged on the maximum scanning position side of the scanner 7. Where 1st and 2nd
Since the connecting devices 21 and 23 have the same configuration, the second connecting device 23
Taking as an example, the configuration is shown in FIG. 9 and FIG. The size detecting scanner 22 is provided with an electromagnetic brake armature 26 via an electromagnetic brake 25, and a pulley 27 is attached to the electromagnetic brake armature 26. The pulley 27 is rotatable with respect to the shaft 28, and the E ring
It is locked by 29.

In such a configuration, if the copying operation is performed, the first
The connecting device 21 acts to connect to the drive wire 11,
The scanner 7 scans according to the drive wire 11. When the document size is detected, the first coupling device 21 is released and the scanner 7 is disconnected from the drive wire 11. Even if the drive wire 11 is driven, the scanner 7 is released.
Does not move.

On the other hand, when viewed from the size detection scanner 22 side, at the time of detecting the document size, the second connecting device 23, that is, the electromagnetic brake 25 and the electromagnetic brake armature 26, brings the drive wire 11 into a connected state and drives the drive wire 11. Accordingly, the size detection scanner 22 starts moving to the reference position Po side. At this time, the lamp 24 is turned on, and the optical sensors 15a and 15b detect the size of the document 1 as described above. When the size detection is completed, the size detection scanner 22 returns to the original position, the second connecting device 23 is released, and the connection with the drive wire 11 is released. As a result, at the time of copying, even if the drive wire 11 is driven and the scanner 7 moves, the size detection scanner 22 does not move.

As in the present embodiment, by mounting the detection device 15 on the size detection scanner 22 provided separately from the copy scanner 7, the optical sensors 15a and 15b are not affected by the heat of the exposure lamp 5. It is possible to improve the characteristics of the detection device 15 and improve the reliability of the detection result.
Further, since the scanner 7 itself is not equipped with the detection device 15, the weight thereof becomes light and the control of starting and braking of the scanner 7 becomes easy.

A fourth embodiment of the present invention will be described with reference to FIG. This embodiment uses a detection device 31 that is a combination of an optical fiber 30 and optical sensors 15a and 15b. One end of the optical fiber 30 serves as a light introducing portion 30a and is supported by the scanner 7 so that the reflected light from the document 1 can be introduced into the optical fiber 30. The optical sensors 15a and 15b are arranged on the fixing portion 32 of the device, and the optical fiber 30
Is optically connected to receive the light transmitted by the other end of the optical fiber 30 (the optical fiber 30 is provided for each of the optical sensors 15a and 15b). Also in the case of this embodiment, since the optical sensor 15a, 15b is not mounted on the scanner 7, the optical sensor 15a, 15b is not affected by the thermal effect of the exposure lamp 5, and the temperature drift of the sensor is greatly reduced. , The reliability of size detection is improved.

By the way, in the case of this embodiment, by providing the lens 33 in the light introducing portion 30a of the optical fiber 30 as shown in FIG. 12, the reliability of size detection can be further improved. For example, if the distance from the tip of the lens 33 to the first surface of the document is set to 5.5 mm and the lens 33 having an outer diameter of 3 mm is used,
The original size detection accuracy was set to 1 mm. That is, it is possible to discriminate even a document having a difference in length of 1 mm. In this respect, the detection accuracy is 3 to 4 mm when the distance between the tip of the light introducing portion 30a of the optical fiber 30 and the surface of the original 1 is set to 5.5 mm without using the lens 33.
FIG. 13 shows actually measured values of changes in sensor circuit output before and after document size detection for comparing detection accuracy. If the solid line is the lens 33, the alternate long and short dash line is the lens 33
Indicates the case of non-use. For example, in the case of only the optical fiber 33 indicated by the alternate long and short dash line, the reflected light to the optical fiber 30 is almost not reflected in the area where the original 1 is absent, so that the sensor circuit output is low and the original 1 Since the reflected light from No. 1 is transmitted through the optical fiber 30, the output of the sensor circuit becomes high. Here, it means that if the output of the sensor circuit changes from a low state to a high state quickly, even a slight difference in the length of the document 1 can be detected, but in the case of only the optical fiber 30, it changes from low to high. You can see that it requires 3 to 4 mm. On the other hand, it can be seen that in the case of using the lens 33, the change from low to high requires only 1 mm. In this way, just add the lens 33,
It is possible to further improve the detection accuracy of the document size. Also in this case, since the optical fiber 30 is used, the optical sensors 15a and 15b are not affected by the thermal effect of the exposure lamp 5.

Of course, these optical fiber 30 systems can be applied to the system of the second embodiment.

Effect Since the present invention is configured as described above, it is possible to reliably and accurately detect the actual document size even if the document is set in an oblique state, a position shift state, or the like.
Also, as the basic configuration of the document size detection, the size of the document can be discriminated by a small number of optical sensors for the type of the document size, so that the document size can be detected easily and reliably at low cost. It will be.

[Brief description of drawings]

1 is a plan view showing a first embodiment of the present invention, FIG. 2 is a schematic side view, FIG. 3 is an enlarged vertical side view showing the vicinity of a scanner, FIG. 4 is a circuit diagram, and FIG. (A) and (b) are plan views showing the detection operation, FIG. 6 is a timing chart showing a second embodiment of the present invention, FIG. 7 is a plan view, and FIG. 8 is a third embodiment of the present invention. A schematic side view showing an example, FIG. 9 is a side view of a connecting device, FIG. 10 is a front view thereof, FIG. 11 is a side view showing a fourth embodiment of the present invention, and FIG. 12 is a modification thereof. Fig. 13 is a side view showing Fig. 13, and Fig. 13 is a characteristic diagram. 1 ... manuscript, 12 ... drive motor (driving means), 15 ... detection device (detection means), 15a, 15b ... optical sensor, 31 ...
Detection device (detection means)

Claims (3)

[Claims] 1. A first detection unit that moves relative to the document surface to detect an end face of the document in the document exposure scanning direction; and a first detection unit that moves simultaneously with respect to the document surface and is orthogonal to the document exposure scanning direction. Second detecting means for detecting the edge of the document in the direction of
In a document size detecting apparatus including a document size determining unit that determines a document size based on an edge detection signal from the first detecting unit and an edge detecting signal from the second detecting unit, the document size determining unit is the A document size detecting apparatus comprising: a delay fetching unit that delays an edge detection signal from the second detecting unit by a predetermined time when the document edge surface is detected by the first detecting unit. 2. A delay take-in means is a first means in the original exposure scanning direction.
The document size detection device according to claim 1, wherein the detection unit and the second detection unit are formed by displacing the positions thereof. 3. The delay acquisition means is formed by shifting the acquisition timings of the end face detection signal from the first detection means and the end portion detection signal from the second detection means. The document size detecting device according to the first section.