JPH0736072B2 - Document size detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a document size detection device in a copying machine.

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 light reflected from the original, a method of detecting light blocking by the original (Japanese Patent Publication No. 60-8492, etc.),
There are various methods such as a method of detecting by cutting off the conductive circuit between the document table and the document cover by placing the document.

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 optical sensors on the document exposure scanner, but even in this case, as many optical sensors as the document size are required, and the same drawbacks are still present. Further, 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.

Further, as disclosed in Japanese Patent Laid-Open No. 53-148442, when the size is judged by detecting the reflected light from the original, the time for scanning the original surface is measured, and this is converted into the length of the original. In some cases, the document size is determined from the length. However, in the case of this method, even if the length of the original is the same, it is not possible to determine the size of the original with different width,
Not enough.

In such a document size determination method, in order to detect the document size, the scanner equipped with the detection means is moved to a position where the document of the maximum size can be detected, and it takes a long time to detect the document. I have a problem to say.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a document size detection apparatus capable of detecting a document size in a short time.

Structure: A scanner for exposing and scanning the surface of a document by mounting an exposure lamp, a driving means for scanning the scanner relative to the surface of the document, and a scanner mounted on the scanner and for a predetermined position in the width direction of the document. And a detection unit having a plurality of optical sensors for detecting the reflected light from the document, and one of the optical sensors is used to determine the movement time from the apparatus reference position, and the detection position from the reference position of the detection unit is used. A conversion means for calculating the moving time up to and converting it to the length of the original, and an original width detected by using the other of the optical sensors for determining the original width and the original length converted by the conversion means. Original size determining means for determining size and original for returning the scanner to the home position by stopping the scanner when the length of the original is detected by the converting means And a size detection driving means.

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 4. 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. 2, 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, one optical sensor 15a 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 is used for determining the document width and receives the reflected light from the edge of the A3 document 1a or the A4 landscape document 1c, but the A4 portrait document 1b, the A5 portrait document 1d.
Also, it is arranged at a position where the reflected light from the A5 landscape original 1e is not received. 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 original 1, the optical sensor
When the outputs of 15a and 15b are ON, there is original 1 (original 1
It corresponds to the state where the reflected light from (1) is received), and when OFF, it corresponds to the state where there is no document 1. Therefore, the optical sensor 15a,
As shown in FIG. 4, 15b is a sensor circuit in which an OP amplifier 17 to which a resistor R ₁ and a capacitor C are connected, and an OP amplifier 18 to which a reference resistor R ₂ and a variable resistor R ₃ are connected are connected in two stages.
Connected to 19.

Also, regarding the operation of the scanner 7, when the scanner 7 starts scanning movement from the reference position Po at a constant speed,
A timer (not shown) is activated to start measuring the time for the movement of the skiner 7. And the light sensor 15
When the output of a changes, the time measurement of the timer is stopped and the conversion means for converting the time taken from the reference position Po of the scanner 7 (and hence the detection device 15) to this position to the length 1 of the document 1 ( (Not shown).

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. Then, the counting time of the timer increases as the scanning of the scanner 7 progresses. When the scanner 7 scans to the end of the original 1c, the original 1c does not exist, and the outputs of the optical sensors 15a and 15b are both ON and OFF.
Will be switched to. At this point, the output of the optical sensor 15a is changed, so that the timer is stopped and the document length is converted to the document length l ₃ based on the time required from the reference position Po of the scanner 7 (detection device 15) at that time. The original 1 set from the value of the original length l ₃ is the A4 horizontal original 1c or
It is temporarily determined to be one of the A5 portrait originals 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. This allows
Since the document width is that of the A4 document, the document 1 set by the document size determination means is determined to be the A4 landscape 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 is determined to be the A5 portrait original 1d.

In this way, the combination of the document length l of the scanner 7 (detection device 15), which is converted and calculated based on the time required by the output change of the optical sensor 15a, and the output state of the optical sensor 15b at that time, the A3 originals 1a, A4 It is possible to determine which size of the document 1 of the portrait document 1b, the A4 landscape document 1c, the A5 portrait document 1d, and the A5 landscape document 1e is set. That is, the optical sensor 15
Reference position Po when a changes from ON to OFF according to each document
As shown in FIG. 2, when the manuscript lengths converted and calculated by the required time are calculated as l ₁ , l ₂ , l ₃ , l ₄ as shown in the following table.

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 version of the original 1 is described. However, when the B version of the original is also used, for example, by appropriately selecting the setting position of the optical sensor 15b, It is possible to detect any of the B and B originals.

Then, the return operation of the scanner 7 when the document size is detected by the preliminary scanning of the scanner 7 is performed as follows. That is, in the preliminary scanning, when the document size is detected (when the output of the optical sensor 15a changes from ON to OFF), the scanner size 7 is stopped by the document size detection driving means and the scanner 7 is immediately moved to the reference position Po.
To return to the standby state for the copying operation. As a result, the time required for the prescanning of the scanner 7, that is, the time required for detecting the document size can be shortened, and particularly in the case of a small size document such as an A5 document, the time can be greatly shortened.

As described above, according to the present embodiment, the length and width of the document can be reliably determined by using a combination of a few sensors for detecting the document size, and the configuration is simple. Further, since such a detection device 15 is mounted on the scanner 7 for exposing and scanning the original, it is not necessary to provide a drive source or an exposure light source dedicated to the detection device 15, and the drive motor 12
The exposure lamp 5 can be shared, and the simplification of the configuration can be increased and the cost can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the optical fiber 30 and the optical sensors 15a and 15b are used.
The detection device 31 is a combination of and. One end of the optical fiber 30 is used as a light introducing portion 30a, and the scanner 7 is provided.
The optical fiber 30 supports the light reflected from the document 1 and can be introduced into the optical fiber 30. And the optical sensor 15a,
The optical fiber 15b is arranged on the fixed portion 32 of the device, and is optically connected so that the light transmitted by the optical fiber 30 is received from the other end of the optical fiber 30 (note that 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 bar 30 as shown in FIG. 6, 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, even a slight difference in length in the scanning direction, that is, a difference in document length of 1 mm can be determined. In this respect, the light introducing section 30 of the optical fiber 30 is used without using the lens 33.
aThe detection accuracy when the distance between the leading edge and one surface of the original is set to 5.5 mm is the actual measurement value of the change in the sensor circuit output before and after the detection of the original size for comparison. The solid line shows the case where the lens 33 is used, and the alternate long and short dash line shows the case where the lens 33 is not used. For example, in the case of only the optical fiber bar 30 indicated by the alternate long and short dash line, the reflected light to this 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 sensor circuit output 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 the optical fiber 30 alone, 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. As described above, only by adding the lens 33, it is possible to further improve the accuracy of detecting the document size. And in this case as well, the optical fiber 30 is used, so the optical sensor
15a and 15b are not affected by the heat of the exposure lamp 5.

Effect Since the present invention is configured as described above, the size of the original can be discriminated by a small number of optical sensors for the type of original size, and the length of the original by the conversion unit can be determined by the operation of the original size detection drive unit. Since the scanner is stopped and the home position is restored at the time of the detection of the size, the time required for detecting the document size can be shortened, which has the effect that the first copy can be obtained quickly.

[Brief description of drawings]

FIG. 1 is a schematic side view showing the first embodiment of the present invention, and FIG.
FIG. 3 is a plan view showing a dimensional relationship, FIG. 3 is an enlarged vertical side view showing the vicinity of a scanner, FIG. 4 is a circuit diagram, FIG. 5 is a side view showing a second embodiment of the present invention, and FIG. FIG. 7 is a side view showing the modification, and FIG. 7 is a characteristic view. 1 ... manuscript, 5 ... exposure lamp, 7 ... scanner, 12
...... Drive motor (driving means), 15 …… Detecting device (detecting means), 15a, 15b …… Optical sensor, 31 …… Detecting device (detecting means)

Claims (1)

[Claims] 1. A scanner for exposing and scanning the surface of an original by mounting an exposure lamp, a driving means for relatively scanning the scanner with respect to the surface of the original, and a scanner mounted on the scanner and arranged in the width direction of the original. A detection unit that is provided at a predetermined position and has a plurality of optical sensors that detect reflected light from the document, and one of the optical sensors is used to determine the movement time from the device reference position, and the reference of the detection unit is used. A conversion unit for calculating the moving time from the position to the detection position and converting it to the length of the document, the document width detected by using the other of the optical sensors for determining the document width, and the document converted by the conversion unit. The original size determining means for determining the original size based on the length and the scanner position is stopped when the length of the original is detected by the converting means, and the home position is restored. Document size detection apparatus according to claim made that the document size detection driving means that.