JPS62124545A - Original size detector - Google Patents

Abstract

PURPOSE:To detect original size easily and securely at low cost by setting plural photosensors differently in detection position in an original scanning direction and detection timing. CONSTITUTION:An original 1 is set on contact glass 2 as an original platen functioning as a reference position Po and pressed by an original cover 3. The original 1 is exposed and scanned by a exposure lamp 5 with a reflecting mirror 4 and a scanner 7 mounting the 1st mirror 6 and reflected light from the original 1 is image-formed on a photosensitive body through the 1st mirror 6 and the 2nd mirror 8, and further a lens, etc., thereby forming an electrostatic latent image. A detecting device 15 for original size detection is mounted on the scanner 7 and uses the exposure lamp 5 as a light source to photodetect the reflected light from the original 1, and a slit 4a is formed at a part of the reflecting mirror 4. This detecting device 15 consists of two photosensors 15a and 15b such as photodiodes and the photosensors 15a and 15b are arranged separately from each other in the breadthwise direction of the original 1.

Description

DETAILED DESCRIPTION OF THE INVENTION 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 In general, in a copying machine, the copying magnification is set depending on the document size, so the document size is automatically detected. The original size detection methods include a method that detects reflected light from the original, a method that detects the blocking of light by the original, a method that detects by placing the original on it and interrupting the conductive circuit between the original platen and the original cover, etc. ,
There are various methods.

Among these methods, for example, Japanese Patent Laid-Open No. 53-'1108
As shown in Japanese Patent No. 37, there is a method for detecting a document by forming irregularities on the document cover and making the optical path of reflected light different between a portion where the document is present and a portion where the document is not present, that is, a portion of the document cover. In addition, the number of optical sensors corresponding to the types of document sizes are installed in the width direction of the document at positions that do not affect image formation on the bottom side of the document table and in the vicinity of the reference line of the document set. There is a system in which the size of the document is detected by turning on the light and turning on the light sensor that receives the reflected light from the document, but turning off the light sensor in the area where the document is not present.

However, in the case of the former method, the surface of the document cover needs to be textured. In addition, in the case of the latter method, the number of optical sensors is equal to the number of types of document sizes, and even if the sizes are different, such as the case of A3 portrait document and A4 landscape document, the same width dimension can be used. It may not be possible to make a determination. In this regard, increasing the number of optical sensors makes it possible to determine minute differences in document length or width, but the mechanism for positioning each optical sensor becomes complicated and adjustment becomes troublesome. This also results in high costs. It is also conceivable to mount an optical sensor in the document exposure scanner, but even in this case, the same number of optical sensors as the original size is required, and the same disadvantage still exists. Furthermore, the number of connection lines between these optical sensors and the control device fixed to the main body of the copying machine also increases.

Furthermore, even if the device is equipped with multiple optical sensors, the document may be placed at an angle with respect to the reference position, or the document may be set out of alignment due to the wind pressure when closing the document pressure plate. There is. If detection is made 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 determined accurately.

Purpose The present invention has been made in view of the above points, and is capable of reliably detecting the size of a document with a low cost and simple configuration using a small number of optical sensors, and is capable of detecting the size of a document even if the document is skewed or misaligned. To provide a document size detection device capable of determining the size of a document even if it is set in a different state.

Structure In order to achieve the above-mentioned object, the present invention provides a detection means having a plurality of optical sensors provided at predetermined positions in the width direction of a document and detects reflected light from the document. A driving means 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 means from the device reference position. A document is provided with a converting means for converting the length of the document into a length of the document, and the document size is determined based on the document width detected by using the other of the optical sensors for determining the document width and the document length converted by the converting device. The size detection device is characterized in that the detection positions or detection timings of the plurality of optical sensors with respect to the document scanning direction are set to be different.

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 serving as a document table with reference to a reference position PO, and is held down by a document cover 3. Such an original 1 is exposed and scanned by a scanner 7 equipped with an exposure lamp 5 having a reflecting mirror 4 and a first mirror 6, and the reflected light from the original 1 is transmitted to the first mirror 6, the second mirror 8, and further, not shown. An electrostatic latent image is formed on the photoreceptor through a lens or the like. The scanner 7 is connected to a drive wire 11 that is passed between pulleys 9 and 10, and exposes and scans one side of the original at a predetermined speed from the base position Po side according to a drive pulley 13 rotated by a drive motor 12. after that,
A return operation will be made to the reference position PO side.

Here, in this embodiment, as shown in FIG. 1, a center reference method is adopted in which the original 1 is set based on a center mark 14 provided at a reference position Po of the contact glass 2. Further, the types of originals used in this embodiment are A size, and as shown in FIG.
A document 1 of any one of the five sizes shown in e is set.

The scanner 7 is equipped with a detection device 15 as a detection means for detecting the size of the original. This detection device 15 receives and detects reflected light from the original 1 using the exposure lamp 5 as a light source, and has a slit 4a formed in a part of the reflecting mirror 4. This detection device 15 includes two optical sensors 15a and 15b such as photodiodes.
It is made up of. These optical sensors 15a, L
5b are spaced apart in the width direction of the document 1. More specifically, one optical sensor 15a is used to determine the amount of movement from the reference position Po, and is arranged on the central reference line, that is, the line of the center mark 14. The other optical sensor 15b is used for document width determination, and receives the reflected light from the edge of the A3 document 1a or the A4 landscape document IC, but it receives the reflected light from the edge of the A3 document 1a or the A4 landscape document IC.
5. It is arranged at a position where it does not receive the reflected light from the horizontal original 1e. For these optical sensors 15a and 15b, as shown in FIG. 3, in order to reduce the receiving range of the reflected light from the document 1 and improve the accuracy of size detection, a light-shielding pipe 16 whose inner surface is blackened, for example, is used. The range of reflected light that can be received is regulated. Further, the sensor output of these optical sensors (photodiodes) 15a and 15b is turned on when the amount of reflected light received is greater than a predetermined reference amount of light, and is turned off when it is less than the reference amount of light. Considering this based on the presence or absence of the original 1, when the outputs of the optical sensors 15a and 15b are ON, the original 1 is present (the state in which the reflected light from the original 1 is received).
, and when it is OFF, it corresponds to a state where there is no document 1. Therefore, as shown in FIG. 4, the optical sensors 15a and 15b are OP
It is connected to a sensor circuit 19 in which an amplifier 17 and a ○P amplifier 18 connected to a reference resistor R2 and a variable resistor R3 are connected in two stages.

Further, an encoder 20 is connected to the drive motor 12. As a result, the number of output pulses of the encoder 20 accompanying the rotation of the drive motor 12 is counted by a counter (not shown), and from the count number when the output of the optical sensor 15a changes, the number of output pulses of the scanner 7 (therefore, the detection device 15) is counted.
) is provided with a conversion means (not shown) that measures the amount of movement Q from the reference position Po and converts it into the document length.

In such a configuration, the document size according to this embodiment is detected by preliminary scanning of the scanner 7 prior to the start of the copying operation. That is, while the exposure lamp 5 is turned on, the scanner 7 performs preliminary scanning from the base position PO.

For example, place an A4 horizontal original 1c on the contact glass 2.
Consider the case where is set. In this case, at the reference position Po, both optical sensors L5a and 15b receive reflected light from the original 1c, and their outputs are turned ON. Then, as the scanning of the scanner 7 progresses, the number of output pulses of the encoder 20 increases. Then, when the scanner 7 advances to the end of the original 1c, the original 1c no longer exists, and the outputs of the optical sensors 15a and 15b both switch from ON to OFF.

At this point, due to the change in the output of the optical sensor 15a, counting of the number of output pulses from the encoder 2o is stopped, and the scanner 7 (detecting device 15) at that time stops counting the number of output pulses from the encoder 2o.
is converted into a movement amount Q3 from the reference position Po. Based on the value of this movement amount Ω3, it is tentatively determined that the set document 1 is either an A4 landscape document 1c or an A5 portrait document 1d. However, at this point, the optical sensor for determining the document width
At the same time, the output of 15b also changes from ON to OFF. As a result, the document width is A4 width, so
The set document 1 is determined to be an A4 landscape document IC.

Also, if the A5 portrait original 1d is set on the contact glass 2, the output of the optical sensor 15a is ON.
It is determined that it is either A4 landscape original IC or A5 portrait original 1d at the time when it changes from OFF to OFF, which is similar to the case where A4 landscape original IC is set, but the optical sensor Since the output of the optical sensor 15b does not change at the time the output of the optical sensor 15a changes, the combination of the outputs of the optical sensors 15a and 15b results in A in this case.
5 is determined to be a portrait document 1d.

In this way, the A3 original 1a, the A4 portrait original lb are determined by the combination of the movement amount Q of the scanner 7 (detection device 15) converted and calculated based on the output change of the optical sensor 15a and the output state of the optical sensor 15b at that time. , A4 landscape original 1c, A5
It is possible to determine which size of the document 1 is set, the portrait document 1d or the A5 landscape document 1e. That is, the amount of movement (original length) from the reference position PO at the time when the optical sensor 15a changes from ON to OFF in accordance with each original is determined as the first
As shown in the figure, ΩII QRT Q31 Q4
Then, the judgment is as shown in the following table.

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

In this embodiment, the case where only the A version original 1 is used has been described, but if, for example, a B version original is also used, an optical sensor for determining the width of the B version original corresponding to the optical sensor 15b may be used. All you need to do is add one more sensor.

By the way, the return operation method of the scanner 7 when detecting the document size by preliminary scanning of the scanner 7 is as follows.
Two methods can be adopted.

The first method is to cause the machine to perform scanning for a maximum scanning length determined by the machine even after the document size is detected, and then to perform a return operation to the reference position Po to enter a standby state for copying operation. In the second method, when the document size is detected during preliminary scanning (when the output of the optical sensor 15a changes from ON to OFF), the scanner 7 is stopped and immediately returned to the reference position Po from that position. This method puts the copy operation in standby mode.

The first method has the advantage of simplifying the operation control system of the scanner 7, and the second method has the advantage of shortening the time required for preliminary scanning of the scanner 7, that is, the time required for document size detection. . In particular, in the case of small-sized originals such as A5 originals, the time can be significantly reduced.

Further, in the above description of the method for detecting the document size, the document size is detected when the scanner 7 scans in a direction away from the reference position PO during preliminary scanning, but it is also possible to detect the document size by moving in the opposite direction. good. That is, the document size is detected when the scanner 7 is in the scanning direction returning from the maximum scanning position to the reference position Po. In 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, in response to the next instruction such as to start copying, the scanner 7 starts scanning toward the reference position Po, and detects the document size during the movement. Also in this method,
The positions of the optical sensors 15a and 15b are the same as in the above explanation, but the operations (○N, 0FF) are reversed. Since the maximum scanning amount is predetermined by the machine (therefore, the number of output pulses of the encoder 2o corresponding to the maximum scanning amount is also determined), the moving length of the scanner 7 is subtracted from this maximum scanning amount. Accordingly, the document size (length) can be easily calculated.

Therefore, in the above explanation, the optical sensor 15a.

Although the description has been made assuming that the optical sensors 15b simultaneously detect the original 1 in the original scanning direction, in this embodiment, these optical sensors 15a and 15b are located at different positions in the original scanning direction as shown in FIGS. It is set. More specifically, the detection device 15 is arranged obliquely so that the optical sensor 15b side detects the document 1 before the optical sensor 15a. The effects of such a configuration will be explained with reference to FIG. First, the original 1 should be set correctly relative to the reference position PO on the contact glass 2.
As shown in FIG. 5, there are cases in which the original 1 is placed obliquely with respect to the reference position PO, and cases where the original 1 is displaced due to wind pressure when closing the original pressure plate 3. be. In such a case, if the optical sensors 15a and 15b are arranged on the same scanning line as shown in FIG. Although the optical sensor 15b is not turned on, and in the actual document 1, this optical sensor 15b also has a width that should be turned on, the data shows that the optical sensor 15a is ON and the optical sensor 15b is OFF. The document size is determined and recognized as an incorrect size. In this regard, according to this embodiment, as shown in FIG. 5(a), the optical sensor 15b side is arranged in advance in the document scanning direction, and the document 1 is placed obliquely as shown in the figure. Even if the optical sensor 15a for document length detection is turned ON/OFF by the document 1, the optical sensor 15b for width detection is always located at a position that can be under the document 1. When detected by 15a, this optical sensor-1
Accurate size detection can be performed by incorporating the data of 5b. Here, the preceding dimension Δα shown in FIG.

Next, a second embodiment of the present invention will be explained with reference to FIGS. 6 and 7. In this embodiment, as shown in FIG. 7 (same as the case shown in FIG. 5(b)), optical sensors 15a, 1
5b are arranged on the same line in the document scanning direction, but the optical sensors 15a and 15 in the document scanning direction are arranged on the same line in the document scanning direction.
The detection timing of b is varied as shown in FIG.

First, let us consider a case in which the data of the optical sensors L5a and 15b are also taken in at the same timing.

In the state of the document 1 as shown in FIG. 6, the optical sensor L5a
, 15b, there is a time difference of time t1 between the output states (ON/OFF states) as shown in FIG.
If the data of 15b is taken in, it means that it is not turned on yet. This leads to incorrect size determination.

In this regard, in this embodiment, first, in scanning in the reading direction F (i.e., forward direction), the scanner 7 starts from the reference position PO and at the sampling timing F after a time t2, the data of the optical sensor 15b is captured. Let's do it. This time t2 can be arbitrarily set to a position (time) from the reference position to the minimum size of the document 1 to be detected. or,
In scanning in the reading direction R (that is, in the reverse direction), the data of the optical sensor 15b is captured at a sampling timing R with a time difference of time t3 after the ON/OFF detection in which the original 1 is detected by the optical sensor 15a. It will be done. This time t can be set at any position (time) where the bending of the document 1 can be ignored (although it is necessary to be before the reference position). This makes it possible to prevent erroneous detection of the document size in either the forward or reverse direction.

Next, a third embodiment of the present invention will be described in FIGS. 8 to 10.
This will be explained using figures. In this embodiment, the scanner 7 is equipped with only the exposure lamp 5 and the first mirror 6, and the drive wire 11 is mounted on the scanner 7.
The scanner 7 and a separate size detection scanner 22 are connected intermittently to each other via a first connecting device 21.
The drive wire 11 is connected to the drive wire 11 by a second connecting device 23 in a disconnectable manner. This size detection scanner 22 is equipped with a lamp 24 separate from the exposure lamp 5, together with the aforementioned optical sensors 15a and 15b, to constitute a detection device 15. The size detection scanner 22 is placed on the maximum scanning position side of the scanner 7. Here, since the first and second coupling devices 21 and 23 have the same configuration, the second coupling device 23 will be taken as an example, and its configuration is shown in FIGS. 9 and 10. The size detection 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. Second pulley 2
7 is rotatable with respect to the shaft 28, and is prevented from being removed by an E-ring 29.

In such a configuration, during a copy operation, the first
The coupling device 21 acts to become coupled to the drive wire 11, and the scanner 7 scans according to the drive wire 11. When the document size is detected, the first clamping device 21 is released and the scanner 7 is disconnected from the drive wire 11, and the scanner 7 does not move even if the drive wire 11 is driven.

On the other hand, when viewed from the size detection scanner 22 side, when the document size is detected, the second coupling device 23, that is, the electromagnetic brake 25
Then, by the action of the electromagnetic brake armature 26, it becomes connected to the drive wire 11, and as the drive wire 11 is driven, the size detection scanner 22 starts moving toward the reference position PO side. At this time, the lamp 24 is on, and the optical sensors 15a and 15b detect the size of the original 1 as described above. When the size detection is completed, the size detection scanner 22 returns to its original position, the second clamping device 23 is released, and the connection to the drive wire 11 is released. As a result, even if the drive wire 11 is driven and the scanner 7 moves during copying, the size detection scanner 22
does not move.

As in this embodiment, by mounting the detection device 15 on the size detection scanner 22 provided separately from the scanner 7 for copying, the optical sensors 15a and 15b are not affected by the heat from the exposure lamp 5. , it is possible to improve the characteristics of the detection device 15 and improve the reliability of the detection results.

Furthermore, since the scanner 7 itself is not equipped with the detection device 15, its weight is reduced, and the activation and braking of the scanner 7 can be easily controlled.

Further, a fourth embodiment of the present invention will be explained with reference to FIG.

In this embodiment, an optical fiber 30 and optical sensors 15a, 1
5b is used in combination with the detection device 31. One end of the optical fiber 30 serves as a light introducing section 30a and is supported by the scanner 7, so that reflected light from the original 1 can be introduced into the optical fiber 30. The optical sensors 15a and 15b are arranged on a fixed part 32 of the device, and are optically connected to receive the light transmitted by the optical fiber 30 from the other end of the optical fiber 30 (the optical fiber 30 is connected to the optical sensor 15a, 15
b). In the case of this embodiment as well, since the optical sensors 15a and 15b are not mounted on the scanner 7, the optical sensors 15a and 15b are not affected by the heat of the exposure lamp 5, and the temperature drift of the sensors is significantly reduced. , the reliability of size detection is improved.

By the way, in the case of this embodiment, the reliability of size detection can be further improved by providing a lens 33 in the light introduction part 30a of the optical fiber 30 as shown in FIG. For example, if the distance from the tip of this lens 33 to the first surface of the document is set to 5.5 cylinders, the lens 33 with an outer diameter of 3M
When using this method, the document size detection accuracy could be set to IM. In other words, the difference in document length is 11 TI.
This means that even I11 can be identified. In this respect, without using the lens 33, the light introducing portion 30a of the optical fiber 30
When the distance between the leading edge and the first surface of the original was set to 5.5M, the detection accuracy was 3 to 4M. FIG. 13 shows actual measured values of changes in sensor circuit output before and after document size detection for comparison of detection accuracy. The solid line indicates the case where the lens 33 is used, and the dashed line indicates the case where the lens 33 is not used. For example, in the case of only the optical fiber 30 shown by the dashed line, the sensor circuit output is low because there is almost no reflected light to the optical fiber 30 in the area where there is no original 1, and the sensor circuit output is low in the area where the original 1 is present. Since the reflected light is transmitted through the optical fiber 30, the output of the sensor circuit increases. Here, if the output of the sensor circuit changes quickly from a low state to a high state, it means that even a slight difference in the length of the document l can be detected, but in the case of only the optical fiber 30, the change from low to high can be detected by 3 It turns out that ~4M is required. On the other hand, it can be seen that in the case of using the lens 33, only one cylinder is required for the change from low to high. In this way, by simply adding the lens 33, it is possible to further improve the accuracy of detecting 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 heat of the exposure lamp 5.

It goes without saying that these optical fiber 30 systems can also be applied to the second embodiment system.

Effects Since the present invention is configured as described above, the actual size of the original can be reliably detected even if the original is set slanted, misaligned, etc., and the basics of original size detection can be detected. As for the structure, the size of the document can be determined using a small number of optical sensors for each type of document size, and therefore, it is possible to detect the document size easily, at low cost, and with certainty.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a first embodiment of the present invention, Fig. 2 is a schematic side view, Fig. 3 is a longitudinal side view showing an enlarged view of the vicinity of the scanner, Fig. 4 is a circuit diagram, and Fig. 5 (a) and (b) are plan views showing the detection operation, FIG. 6 is a timing chart showing the 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 the coupling 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 characteristics. 1... Original document, 12... Drive motor (drive means), 1
5...Detection device (detection means), 15a, 15b...
Optical sensor, 31...detection device (detection means), ¥5,
3 Bi15fu J 6 Figure, 756 times Jq Figure, % JA IB

Claims (1)

[Claims] A detection means having a plurality of optical sensors provided at a predetermined position in the width direction of the document and detecting light reflected from the document is provided, and a driving means for scanning the detection means relative to the surface of the document. and converting means that uses one of the optical sensors to determine the amount of movement from the device reference position and converts the detected position of the detection means to the length of the document by calculating the amount of movement from the device reference position. , in the document size detection device that uses the other of the optical sensors to determine the document width and determines the document size based on the detected document width and the document length converted by the conversion means, the document scanning of the plurality of optical sensors; A document size detection device characterized in that detection positions or detection timings in different directions are set.