JP4833174B2 - Sheet member conveying apparatus, automatic document conveying apparatus and document reading apparatus using the same - Google Patents

Description

  The present invention relates to a sheet member conveying apparatus, and an automatic document conveying apparatus and an original reading apparatus using the sheet member conveying apparatus, and in particular, a sheet member conveying apparatus that conveys a sheet member by sheet member conveying means such as roller conveyance, and the like. The present invention relates to an automatic document feeder that automatically conveys a document, and a document reading device that reads a document while conveying the document to a transported document reading position.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a printer using an electrophotographic method is equipped with a document reading device, and is equipped with a document reading device that automatically feeds and reads a plurality of documents by placing them. Many of them have been used.

  In the document reading apparatus configured as described above, there is known an automatic document conveyance reading apparatus that performs so-called “flowing reading” in which a document is conveyed while the scanning optical system is fixed at a conveyance document reading position for reading the document. It has been. With such a method, it is possible to continuously read a document at a high speed.

  In such an automatic document conveying / reading apparatus, a document conveying device is mounted to convey the document, and in order to accurately detect the leading edge and the trailing edge of the document conveyed at a high speed, the reaction speed is adjusted. Fast optical sensors are used.

  Such a document transport apparatus that transports a document at high speed is required to have reliability and document detection technology that can withstand continuous driving for a long time. However, paper dust generated mainly due to friction between the document and the transport roller exists in the transport path for transporting the document. Therefore, when an optical sensor is used, the paper dust is detected by the optical sensor due to frictional charging. Due to electrostatic adsorption on the surface, irregular reflection occurs on the detection surface, which may cause a false detection that the optical sensor is jammed. This has been a cause of reducing the reliability of the document feeder.

Therefore, as a conventional technique for solving the above-described problem, there has been proposed a technique for preventing erroneous detection due to paper dust by adjusting the light emission amount of the optical sensor according to the number of sheets fed (see Patent Document 1). ).
JP 2003-267589 A

  However, according to the above-described conventional technology, it becomes difficult to cope with an excessive amount of paper dust adhering to the detection surface of the optical sensor. If a large amount of paper dust adheres to the detection surface of the optical sensor during the operation of the apparatus and an erroneous detection occurs, the apparatus determines that the sheet is jammed and interrupts the processing operation. In that case, since the operation | work which removes the sheet | seat accumulated in the apparatus arises, the problem that work efficiency falls remarkably arises.

  Also, if paper dust is excessively attached to the detection surface of the optical sensor, it is necessary to clean the detection surface in order to prevent false detection, and it is necessary to stop the device. Is a factor that significantly lowers.

  The present invention has been made in view of the above-described conventional problems, and eliminates a reduction in work efficiency due to the stoppage of the apparatus due to erroneous detection of an optical sensor, and improves the operating rate of the apparatus. It is an object of the present invention to provide a conveyance device, an automatic document conveyance device using the same, and a document reading device.

In order to solve the above-described problems, the configuration of the sheet member conveying apparatus according to the present invention, and the automatic sheet conveying apparatus and document reading apparatus using the sheet member conveying apparatus are as follows.
The sheet member conveying apparatus according to the present invention includes a conveying path that conveys the sheet member, and a plurality of optical elements that are arranged along the sheet member conveying direction and that receive detection light on the detection surface and detect the presence or absence of the sheet member on the conveying path. Control of the sheet member conveying operation by the sheet member conveying means by determining the presence or absence of the sheet member on the conveying path based on the detection result of the sheet member by the sensor , the sheet member conveying means for conveying the sheet member, and the plurality of optical sensors. In the sheet member conveying apparatus provided with the control means, the control means may be an optical sensor having a mismatched portion in the output signal when there is a mismatched portion when the output signals of the plurality of optical sensors are compared. It is determined that there is paper dust, and a warning is displayed so as to encourage cleaning of the surface of the optical sensor .

  Further, the control means may be configured such that when the frequency of the mismatched portions of the output signals of the plurality of optical sensors exceeds a predetermined value, the surface of the optical sensor having a mismatched portion in the output signal (for example, a detection surface, a light receiving surface, or It is preferable to display a warning so as to encourage cleaning of the light emitting surface.

  The automatic document feeder according to the present invention includes a conveyance path for conveying a document, and a plurality of optical sensors arranged along the document conveyance direction and receiving detection light on a detection surface to detect the presence or absence of the document on the conveyance path. A document tray that can store a plurality of documents, and a document tray that includes a document transport unit that transports a document, and a control unit that controls a document transport operation by the document transport unit. In an automatic document conveying device that automatically feeds a document, the sheet conveying device according to the present invention described above is used as the document conveying device. It is characterized by this.

  The document reading device according to the present invention includes a document reading unit that irradiates a document with light and reads the document by reflected light, and a document that transports the document to a transport document reading position that reads the document while transporting the document. In a document reading device that includes a transport device and has a function of reading a document while transporting a document, the sheet member transport device according to the present invention described above is used as the document transport device.

According to the present invention, a conveyance path that conveys a sheet member, a plurality of optical sensors that are arranged along the sheet member conveyance direction, receive detection light on a detection surface, and detect the presence or absence of the sheet member on the conveyance path, and the sheet Sheet member conveying means for conveying the member, and control means for determining the presence or absence of the sheet member on the conveying path based on the sheet member detection results by the plurality of optical sensors and controlling the sheet member conveying operation by the sheet member conveying means. In the sheet member conveying apparatus having the above, when the control means compares the output signals of the plurality of optical sensors and there is a mismatched part, the optical sensor having the mismatched part in the output signal has paper dust. it is determined that the it was to be a warning display to prompt the cleaning of the optical sensor surface can be the operator easily check the state of the sensor, for example, device operation Even if a large amount of paper dust adheres to one optical sensor, it can be operated continuously without stopping the operation, thereby reducing the work efficiency due to the stoppage of the device. It is possible to realize a sheet member conveying apparatus that improves the rate.

  Further, according to the present invention, the control means prompts cleaning of the surface of the optical sensor having a mismatched portion in the output signal when the frequency of the mismatched portion of the output signals of the plurality of optical sensors exceeds a predetermined value. By displaying such a warning, the operator can easily check the state of the sensor.

  In addition, according to the present invention, a transport path for transporting a document, a plurality of optical sensors arranged along the document transport direction, receiving detection light at a detection surface and detecting the presence or absence of the document on the transport path, and a document A document transporting device including a document transporting unit for transporting and a control unit for controlling a document transporting operation by the document transporting unit; and a document tray capable of storing a plurality of documents, and supplied from the document tray In the automatic document conveying apparatus that automatically conveys the document, the sheet member conveying device according to the present invention described above is used as the document conveying device. It is possible to suppress erroneous detection of a document by the optical sensor during document conveyance and to continuously operate without stopping the operation of the apparatus. Improvement in the operating rate by eliminating a decrease in device an automatic document feeder can be realized which aimed.

  Further, according to the present invention, there is provided a document reading unit that irradiates a document with light and reads the document with the reflected light, and a document transport device that transports the document to a transport document reading position that reads the document while transporting the document. In a document reading apparatus having a function of reading a document while transporting a document, the above-described sheet member transport device according to the present invention is used as the document transport device, so that erroneous detection of a document during document transport can be performed. A document reading apparatus that can be operated continuously without stopping the operation of the apparatus, thereby improving the operating rate of the apparatus without reducing the work efficiency due to the apparatus stopping. realizable.

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory diagram showing a schematic configuration of a document reading apparatus according to the first embodiment of the present invention.
As shown in FIG. 1, the document reading apparatus 100 according to the present embodiment automatically feeds a document along a document transport path F (Auto Document Feeder) (hereinafter referred to as “ADF”). 1, a first image reading unit 10 that reads an image on the front side of the conveyed document, and a second image reading unit 20 that reads an image on the back side of the conveyed document. The ADF 1 has a function of automatically reading the front and back images, and is characterized in that the configuration of the sheet member conveying device according to the present invention is adopted in the ADF 1.

  The first image reading unit 10 is a reduction optical system image reading unit including a light source 11, first to third mirrors 12 a, 12 b, 12 c, a lens 13, and a CCD (image sensor) 14.

  The second image reading means 20 is an image reading means of a reduction optical system composed of a light source 21, first to fourth mirrors 22 a, 22 b, 22 c, 22 d, a lens 23 and a CCD (image sensor) 24. The second image reading means 20 is unitized so that the light source 21, the first to fourth mirrors 22a, 22b, 22c, and 22d, the lens 23, and the CCD 24 form one aggregate.

First, the overall configuration of the document reading apparatus 100 will be described.
As shown in FIG. 1, the document reading apparatus 100 is provided on the upper part of an image forming apparatus (not shown) such as a copying machine or a facsimile machine. As shown in FIG. The main scanning unit 2 is configured to store the ADF 1 to be stored and the first image reading unit 10.

  The ADF 1 is disposed on the upper side of the main scanning unit 2, and the ADF 1 and the main scanning unit 2 are connected by a hinge (not shown). The ADF 1 can be opened and closed with respect to the main scanning unit 2 by the rotation of the hinge.

  Specifically, the ADF 1 mainly includes a document conveyance path (conveyance path) F that conveys a document, a plurality of optical sensors SN that are arranged along the document conveyance direction and detects the presence or absence of a document on the document conveyance path F, and a document. A plurality of pairs of transport rollers 7 that transport along the document transport path F, a registration roller 8 that adjusts the paper feed timing, and a paper discharge roller that discharges the document after image reading to the outside of the apparatus. 9 and a document tray 1 having a document transport device 1 including a control unit (control means) 101 (see FIG. 2) for controlling the document transport operation by the transport roller 7 and the like, and capable of stacking a plurality of documents. 5 and a drawing roller (paper feeding means) 6 for introducing the documents supplied from the document tray 5 into the apparatus one by one so as to automatically convey the document to the document reading position S1 of the main scanning unit 2. Controlled To have.

  The document transport path F is formed in a substantially U shape so as to surround the second image reading unit 20 that is unitized in a side view.

  The main scanning unit 2 mainly includes a housing 3, a platen plate 4 made of a transparent glass plate, and first image reading means 10 accommodated in the housing 3.

  The first image reading means 10 is mainly composed of a light source unit 15 that holds a light source 11 and a first mirror 12a, a mirror unit 16 that holds a second mirror 12b and a third mirror 12c, a lens 13 and a CCD 14.

  The main scanning unit 2 has both a document fixing method in which a user places a document on the platen plate 4 and reads a document image, and a document moving method in which a document image is read while the document is automatically conveyed by the ADF 1. It corresponds to.

  When the main scanning unit 2 reads an original image by the original fixing method, the light source unit 15 and the mirror unit 16 move to home positions corresponding to the original fixing method, respectively. Thereafter, the light source unit 15 scans the image of the original by moving in the sub-scanning direction (left and right with respect to the paper surface) at a constant speed while irradiating the original with light. Similarly, it moves in the sub-scanning direction at a moving speed that is 1/2 of the moving speed.

  The light irradiated from the light source unit 15 and reflected from the document is reflected by the first mirror 12a provided in the light source unit 15, and then the light path is changed by 180 ° by the second and third mirrors 12b and 12c of the mirror unit 16, The light reflected from the three mirrors 12c forms an image on the CCD 14 via the lens 13 and is converted into electrical image data.

  On the other hand, when reading a document image by the document movement method, the light source unit 15 and the mirror unit 16 remain stationary at the home position shown in FIG. 1 and the document conveyed by the ADF 1 so as to pass above the home position. On the other hand, the image is scanned by irradiating light from the light source 11, and the light reflected from the surface side of the original is reflected by the first mirror 12a in the same manner as the original fixing method described above, and then the second of the mirror unit 16. Then, the optical path is changed by 180 ° by the third mirrors 12b and 12c, imaged on the CCD 14 via the lens 13, and converted into electrical image data.

  The second image reading means 20 is mainly composed of a first mirror 22a, a second mirror 22b, a third mirror 22c, a fourth mirror 22d, a lens 23 and a CCD 24, and these members form one aggregate. It is unitized by being accommodated in the unit casing 26. In the second image reading unit 20, the light source 21, the lens 23, and the CCD 24 are the same as those constituting the first image reading unit.

As described above, the second image reading unit 20 reads the image on the back side of the document conveyed on the document conveyance path F when the user requests double-sided reading.
Specifically, after the image on the front side of the document is read by the first image reading unit 10, the second image reading is performed while the document is being conveyed toward the discharge tray 30 along the document conveyance path F. It passes under the light source 21 of the means. At this time, the light source 21 of the second image reading unit 20 irradiates light toward the back side of the document. The light reflected from the back side of the document passes through a reading window 32 which is a light-transmitting member such as glass, and is sequentially converted in optical path by the first to fourth mirrors 22a, 22b, 22c and 22d, and then the lens 23. Then, the image is formed on the CCD 24 and converted into electrical image data.

  Further, the lower surface of the ADF 1 serves as a pressing plate 28 that presses a read document placed on the platen plate 4 of the main scanning unit 2 from above. The pressing plate 28 is a lid 29 that can be opened at a portion facing the light source 21 of the first image reading means 20.

  In the document transport path F, a plurality of optical sensors SN are arranged as document detection means for detecting a document. The optical sensor SN is a reflective sensor installed along the document conveyance path F, and detects the presence or absence of the document G on the document conveyance path F.

  Next, an electrical configuration of the document reading apparatus 100 according to the present embodiment will be described with reference to a block diagram. FIG. 2 is a block diagram showing the main part of the electrical configuration of the document reading apparatus according to this embodiment.

  As shown in FIG. 2, the document reading apparatus 100 mainly includes a control unit (control means) 101, a scanner unit 102, an image processing unit 103, a storage unit 104, a communication unit 105, an operation panel unit 106, and a document scanning unit drive motor 107a. And a driver 107 for controlling driving of the document scanning unit driving motor 107a, a document conveying roller driving motor (sheet member conveying means) 108a, and a driver 108 for controlling driving of the document conveying roller driving motor 108a.

  The control unit 101 is a part that manages operation control of the entire apparatus, and includes a CPU, ROM, RAM, and the like (not shown).

  The scanner unit 102 constitutes an optical scanning system of the first image reading unit 10 and the second image reading unit 20. The CCDs 14 and 24 of the first image reading unit 10 and the second image reading unit 20 are optical reduction type CCDs (Charge Coupled Devices) in the above description, but the same magnification optical type CIS (Contact Image Sensor). But you can.

  The image processing unit 103 converts the optical data read by the first image reading unit 10 or the second image reading unit 20 into electrical image data in units of pages.

  The storage unit 104 includes, for example, a RAM, an EEPROM, a hard disk, and an MO (not shown), and stores data under control controlled by the control unit 101 and various input instruction contents. The storage unit 104 includes an area that functions as a document image storage unit that stores a document image read by the scanner unit 102 and a document storage unit that stores a document including a converted character string code.

  The communication unit 105 is a communication unit that performs two-way communication with an external device original reading 120 such as a connected computer or printer, and transmits data processed by the image processing unit 103 to the external device original reading 120. In addition, a memory for expanding data transmitted from the external device original reading 120 into data that can be handled by the apparatus is provided.

  The operation panel unit 106 is used when inputting an operation mode (designation of single-sided reading or double-sided reading) at the time of reading a document. Although not shown, the operation panel unit 106 is on the front side (operation side) of the document reading device 100. ). Specifically, for example, the upper part of the main scanning unit 2 may be formed to protrude toward the front side of the ADF 1, and the operation panel unit 106 may be provided on the upper surface portion.

  The document scanning unit drive motor 107a is a motor for moving the light source unit 15 and the mirror unit 16 in the sub-scanning direction at an appropriate speed when reading a document image by the document fixing method. The driver 107 appropriately controls the drive.

The document transport roller driving motor 108 a is a motor that drives each of the rollers such as the calling roller 6, the transport roller 7, the registration roller 8, and the paper discharge roller 9 disposed in the document transport path F, and is controlled by the control unit 101. The drive is appropriately controlled by the driver 108.
The document transport roller drive motor 108a is configured to drive the transport roller 7 via a clutch (not shown).

  The clutch transmits the driving force of the document conveying roller driving motor 108a constituting the sheet member conveying unit to a conveying belt (not shown) (endless belt driving unit) when the control signal from the control unit 101 is on. Specifically, the clutch drive is switched on / off by a driver 108 controlled by a control signal from the control unit 101.

Next, a characteristic configuration of the ADF 1 according to the present embodiment will be described with reference to the drawings.
FIG. 3 is a circuit diagram showing a configuration of an optical sensor constituting the ADF according to the present embodiment, FIG. 4A is an explanatory diagram showing a state in which a document is detected by the optical sensor, and FIG. 3B is a diagram showing a document by the optical sensor. FIG. 5 is an explanatory diagram showing a state of erroneous detection by the optical sensor, and FIG. 6 is a positional relationship between the first optical sensor SN1 and the second optical sensor SN2 of the optical sensors. It is explanatory drawing which shows.

  In the ADF 1 according to the present embodiment, as shown in FIG. 1, a plurality of optical sensors SN are arranged on a document transport path F from the document tray 5 side of the document transport path F to the discharge tray 30 side.

  As shown in FIG. 3, the optical sensor SN includes a light emitting unit SNa, a light receiving unit SNb, and a comparator SNc, and as shown in FIG. 4A, the light emitting unit SNa and the light receiving unit SNb are connected to the original G. Is a reflective sensor disposed on the same side.

The light emitting unit SNa is an infrared light emitting LED, and irradiates infrared light toward the document.
The light receiving unit SNb is a phototransistor that receives reflected light from a document.
The comparator SNc compares the output of the light receiving unit SNb with a reference voltage to determine the presence or absence of a document, and outputs that the document is present if the output voltage of the light receiving unit SNb is higher than the reference voltage.

Here, document detection by the optical sensor SN will be described.
When the document G is transported to the document transport path F and the document G comes to a position facing the optical sensor SN, as shown in FIG. 4A, the optical sensor SN receives the light emitted from the light emitting unit SNa. When the light is reflected from the document surface and is incident on the light receiving unit SNb, a signal indicating that there is a document is output from the light receiving unit SNb. That is, the document is present.

  On the other hand, when the document G is not conveyed, as shown in FIG. 4B, the optical sensor SN emits light from the light emitting unit SNa downward in the figure and does not enter the light receiving unit SNb. A signal indicating that there is a document is not output from the light receiving unit SNb. That is, there is no original.

  When paper dust or the like generated in the document transport path F adheres to the light emitting portion SNa or the light receiving portion SNb of the optical sensor SN, as shown in FIG. There is a case where a signal indicating that there is a document is output from the light receiving unit SNb even when the document G is incident and the document G does not exist. This is a false detection.

  As shown in FIG. 1, the optical sensor SN configured as described above has one conveyance roller on the document conveyance path F between the conveyance rollers 7a and 7b from the upstream side to the downstream side in the document conveyance direction. 7b and 7c, two places between the conveyance roller 7c and the registration roller 8, and one place between the registration roller 8 and the conveyance roller 7d via the platen roller 8a.

  In the present embodiment, the two optical sensors SN disposed between the transport rollers 7b and 7c are referred to as a first optical sensor SN1 and a second optical sensor SN2 from the upstream side in the document transport direction.

  As shown in FIG. 6, the first optical sensor SN1 and the second optical sensor SN2 provide a distance L1 between the conveyance rollers 7a and 7b along the document conveyance direction (arrow A direction). They are arranged at a distance of L2 in the direction substantially perpendicular to the conveying direction (arrow B direction), that is, in the document width direction. Reference numeral 108a1 is a document conveying roller driving motor for driving the conveying roller 7b, and reference numeral 108a2 is a document conveying roller driving motor for driving the conveying roller 7c.

  In this way, by arranging the first optical sensor SN1 and the second optical sensor SN2 apart from each other in the document conveyance direction and the document width direction, a lump of paper dust is caused to flow in the document conveyance direction by the air flow accompanying document conveyance. Even if it moves, the possibility of being detected by one of the first optical sensor SN1 and the second optical sensor SN2 and being detected again by the other sensor can be reduced.

  Next, a peripheral circuit of the optical sensor SN according to the present embodiment will be described with reference to a circuit diagram. FIG. 7 is a circuit diagram showing a configuration of a peripheral circuit of the optical sensor according to the present embodiment.

The document reading apparatus 100 includes a control circuit 110 that controls the operation of the document scanning unit driving motor 107a that drives the conveyance roller 7a. As shown in FIG. 7, the control circuit 110 controls the operation of the document scanning unit drive motor 107a based on the output signals from the first optical sensor SN1 and the second optical sensor SN2. Shift register 111 as delay means for delaying the output signal from the optical sensor SN1, logical sum means 112 for outputting a logical sum signal based on the output signals from the first optical sensor SN1 and the second optical sensor SN2, and carrier Control means 113 for controlling the operation of the roller, delay control signal generation means 114 for delaying the input signal, motor drive signal generation means 115 for outputting a signal for operating the drive motor for driving the transport roller, and the drive motor A driver 108 for driving is provided.
Note that the control unit 113 may be one in which the above-described control unit 101 has the function of the control unit 113.

  As shown in FIG. 7, the output signal from the first optical sensor SN1 is input to the shift register 111 and output as an output signal (delayed signal) OP2 from the shift register 111.

  The output signal OP1 from the second optical sensor SN2 and the output signal OP2 from the shift register 111 are input to the logical sum means (OR gate) 112, and the output signal (logical sum signal) OP3 from the logical sum means 112 is the document. It is input to the control means 113 as a G detection signal.

  The delay control signal generation unit 114 generates a delay control signal (CLK supplied to the shift register 111) 114a based on the speed control signal (drive signal) 113a output from the control unit 113.

The delay time T by the shift register 111 is determined by the document conveyance speed V and the distance L1, and is the time until the document G reaches the position of the second optical sensor SN2 from the position of the first optical sensor SN1.
Therefore, the delay time T is
T = L1 ÷ V
Is required.

Since the document transport speed V is obtained from the speed control signal 113 a, the delay control signal generation unit 114 determines the delay control signal 114 a based on the document transport speed V and the delay time T obtained from the speed control signal 113 a and the number of stages of the shift register 111. The clock frequency f is obtained.
For example, if the number of stages of the shift register 111 is n, the clock frequency f is
f = 1 ÷ T × n
Is required.

  The speed control signal 113a of the control unit 113 is converted into, for example, a stepping motor drive signal by the motor drive signal generation unit 115 and drives the document transport roller drive motor 108a1 upstream in the document transport direction via the driver 108. The document transport roller drive motor 108a1 uses a stepping motor.

Next, the output of the optical sensor SN according to this embodiment will be described.
FIG. 8 is an explanatory view showing the output state of the conventional optical sensor, FIG. 9 is an explanatory view showing the output state of the optical sensor according to the present embodiment in a normal state, and FIG. 10 is paper dust of the optical sensor according to the present embodiment. It is explanatory drawing which shows the output state when it misdetects by.

First, the output of the conventional optical sensor SN will be described.
When the original G is detected by the optical sensor SN in the conventional manner, as shown in FIG. 8, the signal level at the position where the original G is detected is L level, and between the original G and the original G (the original G is detected). The signal level at the place where it is not) becomes the H level. When paper dust is detected between the original G and the original G, the signal level becomes L level.

  Thus, conventionally, even when the document G does not exist, when the paper dust is detected, the signal level output from the optical sensor SN becomes the same L level as when there is no document, resulting in false detection. .

  Next, outputs of the first optical sensor SN1 and the second optical sensor SN2 in the control circuit 110 according to the present embodiment will be described.

  When the first optical sensor SN1 and the second optical sensor SN2 are normal, the output of the first optical sensor SN1 is delayed by the time T by the shift register 111 as shown in FIG. The output signal OP2 is output at a timing that coincides with the output signal OP1 from the second optical sensor SN2. Based on these output signals OP1 and OP2, an OR signal 112 generates an output signal (logical sum signal) OP3. This output signal OP3 is output from the logical sum means 112 to the control means 113 as a document detection signal.

  On the other hand, when paper dust or the like adheres to the first optical sensor SN1, as shown in FIG. 10, the first optical sensor SN1 detects false detection by detecting paper dust, that is, the signal level is L level. Since the signal levels output from both the first optical sensor SN1 and the second optical sensor SN2 hardly become the L level at the same time, the logical sum means 112 is generated. The output signal (logical sum signal) OP3 having the same H level as in the state where there is no paper dust is generated. This output signal OP3 is output from the logical sum means 112 to the control means 113 as a document detection signal.

  Further, when paper dust or the like adheres to the second optical sensor SN2, as shown in FIG. 10, in the same manner as in the first optical sensor SN1 described above, there is no paper dust in the logical sum means 112. The same output signal OP3 is generated.

  Accordingly, even if any of the first optical sensor SN1 and the second optical sensor SN2 causes an erroneous detection of paper dust, the logical sum means 112 outputs the H level document detection signal OP3.

  The control means 113 monitors the output from the optical sensor SN (here, the first optical sensor SN1 and the second optical sensor SN2), and the sensor output is changed from the H level to the L level by detecting the leading edge of the document G. If it does not change from the L level to the H level within a predetermined time after the change, it is determined that a jam has occurred and the document conveyance reading operation is stopped.

  Similarly, if the sensor output does not change from the H level to the L level within a predetermined time after the sensor output changes from the L level to the H level due to the detection of the trailing edge of the document G, it is determined that a jam has occurred, and the document conveyance reading operation Is supposed to stop.

Since it comprised as mentioned above, according to 1st Embodiment, when erroneous detection arises in the optical sensor SN conventionally with paper dust, since sensor output will change outside the range of the time assumed, it will determine with jam. However, as described above, the output signal from the first optical sensor SN1 is delayed, and the output signal from the second optical sensor SN2 is input to the logical sum means 112 at the same timing to obtain a logical sum signal. Therefore, by generating the output signal OP3 that eliminates erroneous detection due to paper dust, erroneous detection due to paper dust can be prevented.
Thereby, it is possible to continuously operate the document reading apparatus 100 without stopping the operation thereof, and thereby it is possible to improve the operation rate of the apparatus without reducing the work efficiency due to the stop of the apparatus. .

  In the first embodiment, a reflective sensor is used as the optical sensor SN. However, a transmissive sensor may be used. Further, the position and the number of the optical sensors SN are not limited to the present embodiment.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described with reference to the drawings.
FIG. 11 is an explanatory view showing the positional relationship of the optical sensors constituting the document reading apparatus according to the second embodiment, FIG. 12 is a block diagram showing the main part of the electrical configuration of the document reading apparatus, and FIG. 13 is the second embodiment. It is explanatory drawing which shows the output state when it misdetects by the paper dust etc. of the optical sensor which concerns on a form.

As shown in FIG. 11, the document reading apparatus 200 according to the second embodiment has substantially the same configuration as that of the document reading apparatus 100 according to the first embodiment described above, and includes the first optical sensor SN1 and the first optical sensor SN1. In addition to the second optical sensor SN2, a third optical sensor SN3 is provided.
In the document reading apparatus 200, the same reference numerals are given to the same configurations as those of the document reading apparatus 100 according to the first embodiment described above, and the description thereof is omitted.

  As shown in FIG. 11, the third optical sensor SN3 is provided with a distance L1 between the conveyance rollers 7a and 7b and the first optical sensor SN1 along the document conveyance direction (arrow A direction). Thus, the distance L2 is disposed at a position substantially opposite to the document transport direction (in the direction of arrow B), that is, in the document width direction, opposite to the second optical sensor SN2.

  Specifically, in the second embodiment, the first optical sensor SN1 is arranged at a substantially central portion in the document width direction on the document conveyance path, and the second optical sensor SN2 and the third optical sensor SN3 are arranged in the first. These optical sensors SN1 are arranged in a so-called staggered arrangement in which distances L2 are provided in opposite directions in the document width direction.

  The document reading apparatus 200 includes a control circuit 210 that controls the operation of the document scanning unit driving motor 107a that drives the conveyance roller 7a. As shown in FIG. 12, the control circuit 210 controls the operation of the document scanning unit drive motor 107a based on output signals from the first optical sensor SN1, the second optical sensor SN2, and the third optical sensor SN3. Thus, it has the same configuration as the control circuit 110 in the first embodiment, and instead of the logical sum means 112 in the first embodiment, an output signal OP1 from the second optical sensor SN2 and an output signal from the shift register 111. An OR circuit 212 to which the output signal OP4 from OP2 and the third optical sensor SN3 is input is provided.

Next, the output of the optical sensor SN according to the second embodiment will be described.
When paper dust or the like adheres to the first optical sensor SN1, as shown in FIG. 13, in the output from the first optical sensor SN1, the signal level may become L level by detecting the paper dust. Even if it occurs suddenly, the signal levels output from the first optical sensor SN1, the second optical sensor SN2, and the third optical sensor SN3 rarely become L level at the same time. The same output signal (logical sum signal) OP3 as that without paper dust is generated. This output signal OP3 is output from the logical sum means 212 to the control means 113 as a document detection signal.

  Even when paper dust or the like adheres to the second optical sensor SN2, as in the case of the first optical sensor SN1 described above, the OR signal 212 generates the same output signal OP3 as when there is no paper dust. The

  Further, even when paper dust or the like adheres to the third optical sensor SN3, as in the case of the first optical sensor SN1 and the second optical sensor SN2 described above, there is no paper dust by the logical sum means 212. The same output signal OP3 is generated.

  Therefore, even if any one of the first optical sensor SN1, the second optical sensor SN2, and the third optical sensor SN3 detects a paper dust error, the OR circuit 212 generates a correct document detection signal OP3. Is output.

  Since it comprised as mentioned above, according to 2nd Embodiment, a logical sum is acquired by the logical sum means 212 based on the output from 1st optical sensor SN1, 2nd optical sensor SN2, and 3rd optical sensor SN3. By doing so, the false detection of the optical sensor resulting from paper dust can be reduced further.

(Third embodiment)
Next, a third embodiment according to the present invention will be described with reference to the drawings.
FIG. 14 is a block diagram showing the main part of the electrical configuration of the document reading apparatus according to the third embodiment, FIG. 15 is an explanatory view showing the output state of the optical sensor according to the third embodiment in a normal state, and FIG. It is explanatory drawing which shows the output state when erroneously detecting with the paper dust etc. of an optical sensor.

The document reading apparatus (not shown) according to the third embodiment has substantially the same configuration as that of the document reading apparatus 100 according to the first embodiment described above, and as shown in FIG. An EX-OR gate 317 to which outputs from the first optical sensor SN1 and the second optical sensor SN2 are input is provided.
In the control circuit 310, the same reference numerals are given to the same configurations as those of the control circuit 110 according to the first embodiment described above, and the description thereof is omitted.

  As shown in FIG. 14, the EX-OR gate 317 is connected to the OR circuit 112 so that the output signal OP1 from the second optical sensor SN2 and the output signal OP2 from the output signal OP2 from the shift register 111 are input. Connected in parallel.

  The EX-OR gate 317 detects paper dust when the output signals from the first optical sensor SN1 and the second optical sensor SN2 do not match, that is, one sensor detects paper dust. If not, an output signal whose signal level is H level is output.

  In the document reading apparatus according to the third embodiment, when the number of outputs of the H level output signal output from the EX-OR gate 317 or the accumulated time when the output signal is at the H level exceeds a predetermined value, A display for prompting the sensor to be cleaned is displayed on a display device (not shown).

Next, the output of the optical sensor SN according to the third embodiment will be described.
The output signals from the first optical sensor SN1 and the second optical sensor SN2 are output from the output signal OP1 from the second optical sensor SN2 and the first optical sensor SN1 in a normal state as shown in FIG. Then, the output signal OP2 delayed by the time T by the shift register 111 is output at the same timing. At this time, the output signal OP5 output from the EX-OR gate 317 is output to the control means 113 at the L level.

  On the other hand, when the output signals from the first optical sensor SN1 and the second optical sensor SN2 do not match, the output signal OP5 output from the EX-OR gate 317 is output to the control means 113 at the H level.

  In the third embodiment, when paper dust or the like adheres to the second optical sensor SN2, it is detected by the second optical sensor SN2 and output from the second optical sensor SN2 as shown in FIG. The signal level of the output signal OP1 becomes H level. At this time, in the EX-OR gate 317, since the output signals from the first optical sensor SN1 and the second optical sensor SN2 do not match, the output signal OP5 output from the EX-OR gate 317 becomes H level, It is output to the control means 113. In other words, the EX-OR gate 317 outputs a false detection to the control means 113.

  The control means 113 records the number of times of the H level output signal OP5 output from the EX-OR gate 317 or the accumulated time during which the H level is output, and displays a display panel (not shown) when a predetermined number of times or a predetermined value is exceeded. Instructed to display the second optical sensor SN2 so as to facilitate cleaning.

  Since it comprised as mentioned above, according to 3rd Embodiment, by measuring the generation | occurrence | production degree of the paper dust false detection by 1st optical sensor SN1 and 2nd optical sensor SN2, it is a serviceman of a sensor detection surface. Cleaning can be promoted, and cleaning can be performed at an appropriate timing. As a result, it is possible to realize a document reading apparatus that eliminates a reduction in work efficiency due to the stoppage of the apparatus and improves the operation rate of the apparatus.

  The preferred embodiments of the present invention have been described above. However, it goes without saying that the present invention is not limited to the above-described examples, and those skilled in the art will recognize various modifications within the scope of the claims. It is obvious that modifications can be conceived, and it is understood that they also belong to the technical scope of the present invention.

  For example, as long as the apparatus has a configuration for conveying sheet members one by one, the present invention can be easily applied without being limited to the configuration of the document conveying apparatus of the present embodiment.

1 is an explanatory diagram showing a schematic configuration of a document reading apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a main part of an electrical configuration of the document reading device. It is a circuit diagram which shows the structure of the optical sensor which comprises ADF of the said original reading apparatus. (A) is explanatory drawing which shows the state which detected the original document with the said optical sensor, (b) is explanatory drawing which shows the state which does not detect an original document with the said optical sensor. It is explanatory drawing which shows the state of the misdetection by the said optical sensor. It is explanatory drawing which shows the positional relationship of 1st optical sensor SN1 and 2nd optical sensor SN2 among the said optical sensors. It is a circuit diagram which shows the structure of the peripheral circuit of the said optical sensor. It is explanatory drawing which shows the output state of the conventional optical sensor. It is explanatory drawing which shows the output state in the normal time of the optical sensor which concerns on 1st Embodiment. It is explanatory drawing which shows the output state when erroneously detecting with the paper dust etc. of the said optical sensor. It is explanatory drawing which shows the positional relationship of the optical sensor which comprises the original document reading apparatus concerning 2nd Embodiment of this invention. FIG. 2 is a block diagram illustrating a main part of an electrical configuration of the document reading device. It is explanatory drawing which shows the output state when it misdetects by the paper dust etc. of the optical sensor used for the said original reading apparatus. It is a block diagram which shows the principal part of the electrical constitution of the original document reading apparatus concerning 3rd Embodiment of this invention. It is explanatory drawing which shows the output state in the normal time of the optical sensor which concerns on 3rd Embodiment. It is explanatory drawing which shows the output state when erroneously detecting with the paper dust etc. of the said optical sensor.

Explanation of symbols

1 Document conveying device (sheet member conveying device)
100, 200 Document reading apparatus 101 Control unit (control means)
108a1, 108a2 Document transport roller drive motors 110, 210, 310 Control circuit 111 Shift register (delay means)
112, 212 logical sum means 113 control means 113a speed control signal 114 delay control signal generation means 114a delay control signal 115 motor drive signal generation means 317 EX-OR gate F document conveyance path (conveyance path)
G Document (sheet member)
OP1, OP2, OP3, OP4, OP5 Output signal SN optical sensor SN1 first optical sensor SN2 second optical sensor SN3 third optical sensor

Claims (4)

A conveyance path that conveys the sheet member, a plurality of optical sensors that are arranged along the sheet member conveyance direction, receive detection light on the detection surface and detect the presence or absence of the sheet member on the conveyance path, and a sheet member that conveys the sheet member A sheet member comprising: a conveying unit; and a control unit configured to determine the presence or absence of the sheet member on the conveying path based on the detection result of the sheet member by the plurality of optical sensors , and to control the conveying operation of the sheet member by the sheet member conveying unit. In the transport device,
When the control means compares the output signals of the plurality of optical sensors and there is a mismatched portion, the control means determines that there is paper dust in the optical sensor having the mismatched portion in the output signal. A sheet member conveying apparatus, characterized by displaying a warning so as to prompt cleaning . The control means displays a warning so as to prompt cleaning of the surface of the optical sensor having the mismatched portion in the output signal when the frequency of the mismatched portion of the output signals of the plurality of optical sensors exceeds a predetermined value. The sheet member conveying apparatus according to claim 1 . A transport path for transporting a document, a plurality of optical sensors arranged along the document transport direction and receiving detection light on the detection surface to detect the presence or absence of the document on the transport path, a document transport means for transporting the document, A document conveying device including a control unit that controls a document conveying operation by the document conveying unit, and a document tray capable of storing a plurality of documents, and a document supplied from the document tray is introduced into the device. An automatic document feeder that automatically feeds a document including a paper feeding unit,
An automatic document conveying device using the sheet conveying device according to claim 1 or 2 as the document conveying device. A document reading means for irradiating a document with light and reading the document with reflected light, and a document transport device for transporting the document to a transport document reading position for reading the document while transporting the document, the document while transporting the document In a document reader having a function of reading,
An original reading apparatus using the sheet member conveying apparatus according to claim 1 or 2 as the original conveying apparatus.

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