JP2003137457A - Paper feeder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder device which can detect double feed by detecting both a paper type and a paper thickness using reflect light intensity and transparent light intensity based on the fact that reflect light varies according to paper type. SOLUTION: A paper type detection unit, which detects a paper type of a document 2, and a paper thickness unit, which detects a paper thickness, components of a multi feed detection unit are mounted in parallel between a separation assembly and a feeder roller 8. Both the units detect reflect and transparent light intensity using light emitting diodes 7a and 6a and light receiving elements 7b and 6b. Information collected by the two sensors is recorded as base data of transparent light intensity detected by the paper thickness detection unit corresponding to reflect light intensity detected by the paper type detection unit, and detection of multi feed will be made by comparing information collected from the two sensors and the recorded base data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device used in an image reading apparatus such as a copying machine, a printer, a facsimile, an image scanner, etc., and particularly, two or more sheets of a document or the like to be conveyed are fed. The present invention relates to a sheet feeding device having a double feed detection function for detecting double feed at the time.

[0002]

2. Description of the Related Art An image reading device such as an image scanner is provided with a paper feeding device for feeding a document set on a paper feeding tray. This kind of paper feeding device is to feed out stacked documents one by one from the top, and most of them are provided with a double feed preventing mechanism in which two or more documents are fed out due to friction between overlapping documents. .

However, in the conventional document double feed detection mechanism,
If the original is a mixture of thin paper and thick paper, it is difficult to set the reference signal. For example, when a thick paper is sent after a thin paper, there is a problem that a signal that the double feed is detected is output immediately. Also,
When a thin paper is fed in a double-feed state after a thick paper, it is determined that the paper is normally fed even if the paper thickness is detected, and the image is read. Occasionally, it cannot be prevented. More specifically, plain paper (60
(About K sheets) If originals and thin originals are mixed, both when the thin originals are conveyed after the plain paper and when the plain originals are conveyed after the thin original, it is mistaken as a double feed. I will detect it.

In order to solve such a problem, for example, it is necessary to form originals using only papers of a certain thickness without mixing originals of various paper thicknesses. However, for example, for a document in which tracing paper and general copying paper are mixed, only the tracing paper is separately copied to make the document thickness uniform, which increases the burden on the operator. At the same time, there is a problem that the efficiency of the work using the image reading device is reduced.

In a general manuscript, a paper for composing a text portion is a general copying paper and a drawing or the like is often a tracing paper, and the sizes of these papers are slightly different. Is often used. However, in the conventional image reading apparatus, the paper size information is used only as the information on the feeding of the paper from the paper feed tray, and the paper thickness detecting device detects the double feeding of the paper. Since only the obtained information is used, the above-mentioned problem of false detection of double feeding occurs.

In order to solve this, the apparatus disclosed in Japanese Patent Laid-Open No. 5-43091 includes a paper thickness detecting device for detecting the paper thickness of the paper and a paper size detecting device for detecting the size of the paper. They are arranged and the information on the paper thickness and the size obtained from the two types of sensors is input to the control device to detect the double feed. In other words, paying attention to the fact that papers with different paper quality or paper thickness often have different sizes, and in addition to the paper thickness detection device, a means for detecting double feeding using information from the paper size detection device is provided. Even when different types of sheets are continuously fed, it is possible to accurately determine the double feeding of the sheets.

However, in this technique, it is useful that there are many cases that papers of different paper quality or paper thickness also have different sizes, but in reality, the paper size is the same and the paper type (paper quality or paper thickness ) Are often used. For example, the originals that make up the document part are
Since it is a 4 size copy paper, and the graphs and drawings attached to it often use A4 tracing paper of the same size, documents with different paper thicknesses are mixed on the same paper size. In this case, it will be erroneously detected as a double feed, and in many cases, the above problems cannot be solved in practice.

Further, the apparatus disclosed in Japanese Patent Laid-Open No. 6-5868 discloses a sheet type of an original (transparent original, reflective original,
Focusing on the fact that the amount of light transmitted through the original differs depending on the thin paper original, the paper type of the original is identified based on the output signal of the CCD. However, this technique is paper identification assuming that the originals are not double-fed. Therefore, the transmitted original has a large transmitted light, the thin original has a small transmitted light, and the reflected original has a small transmitted light. Although the originals are identified by this, for example, when the amount of transmitted light when several thin paper originals are multifed and the transmitted scene when the number of reflected originals is one are almost the same, Even if several sheets of paper have been fed in multiple sheets, it is detected as one original document instead of double feeding, and in many cases the above problems cannot be solved.

The present invention has been made by paying attention to the fact that, for example, in the case of documents such as plain paper for copying, and mixed originals of tracing paper with graphs and drawings, the reflected light differs depending on the paper type. Yes, it detects double feed by detecting both paper type and paper thickness by combining the amount of reflected light and the amount of transmitted light, and makes it possible to detect double feed when the paper size is the same and the paper types are different. .

[0010]

According to a first aspect of the present invention, there is provided a sheet stacking device capable of stacking a plurality of sheets of originals or transfer sheets in order to achieve the above object. A sheet feeding means for feeding the sheets stacked on the sheet stacking means, a separating means for separating the sheet to be fed from other sheets, and a double feed detecting means for detecting the double feed of two or more sheets In the sheet feeding device provided, the double feed detection unit includes a paper thickness detection unit and a paper type detection unit which are provided in a transport path on the downstream side of the separation unit in the sheet transport direction, and information from the double feed detection unit is provided. A recording means for recording data of a reference paper thickness corresponding to the paper type of the paper, a means for comparing the reference data with information from the double feed detecting means, and the paper. Is provided with a double feed determination means for determining whether or not The double feed determining means uses the paper thickness data of the paper being conveyed obtained from the paper thickness detecting means and the paper type data of the paper being conveyed outputted by the paper type detecting means to double feed the original being conveyed. It is characterized by determining.

According to a second aspect of the present invention, in order to achieve the above object, in the sheet feeding device of the first aspect, the paper thickness detecting means and the paper type detecting means are arranged in the same range of a document being conveyed. It is characterized by being arranged so as to detect.

According to a third aspect of the present invention, in order to achieve the above object, in the sheet feeding device according to the first or second aspect, the paper type detecting means is a reflection type sensor including a light emitting diode and a light receiving element. It is characterized in that the light emitting diode and the light receiving element are arranged so as to sandwich the paper thickness detecting means in the paper conveying direction.

According to a fourth aspect of the present invention, in order to achieve the above object, in the paper feeding device according to the first or second aspect, the paper thickness detecting means includes a transmissive sensor including a light emitting diode and a light receiving element. The paper type detecting means comprises a reflection type sensor including a light emitting diode and a light receiving element, and the light emitting diode and the light receiving element of the paper type detecting means are connected to the light emitting diode or the light receiving element of the paper thickness detecting means. And a background surface of the paper type detection range of the paper by the paper type detection means is formed of a member having a black surface.

According to a fifth aspect of the present invention, in order to achieve the above object, in the sheet feeding device according to any one of the first to fourth aspects, the means for setting the reference sheet thickness data is just before the detecting operation. It is characterized in that the data of the paper thickness of the originals of the same paper type that have been conveyed is stored and the data is used as a reference value.

According to a sixth aspect of the present invention, in order to achieve the above object, in the sheet feeding device according to any one of the first to fourth aspects, the means for setting the reference sheet thickness data is just before the detecting operation. Data of paper thickness obtained by calculating an average value for a fixed number of originals of the same paper type is stored, and the data is used as a reference value.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments describe only a document image reading apparatus in which the sheet feeding device of the present invention is applied as a document sheet feeding device, but the present invention is not limited to this, and is applicable to various image forming apparatuses. It can be used as a paper feed device for paper such as originals and transfer paper.

FIG. 1 is a schematic sectional view showing a first embodiment of the present invention. In the figure, 1 is a paper feed tray, 2 is a document, 3 is a pickup roller, 4 is a separation roller, 5 is a reverse roller, 8 is a transport roller, 9 is an ADF document glass, 10 is a paper discharge roller, and 21 is a paper discharge tray. is there. 11 is a light source,
12 is a reflector, 13 is a first mirror, 14 is a first carriage base, 15 is a second mirror, 16 is a third mirror, 17
Is a second carriage base, 18 is a lens, 19 is a CC
D and 20 are image reading plates.

The operation of this image reading apparatus will be briefly described. First, the uppermost original 2 of the original stack stacked on the paper feed tray 1 is separated from other originals on the upper side by the pickup roller 3 and sent to the separating unit. The separation unit is composed of a separation roller 4 that rotates in the direction in which the original 2 is fed and a reverse roller 5 that rotates in the direction in which the original 2 is returned to the paper feed tray 1. When a plurality of originals 2 ... Further, only the uppermost one sheet is sent to the transport roller 8. The reverse roller 5 has a built-in torque limiter. When the number of originals 2 is one, the reverse roller 5 also rotates in the direction in which the originals are fed, as will be described later.

A paper type detection unit for detecting the paper type of the original 2 and a paper thickness detection unit for detecting the paper thickness are provided between the separating unit and the transport roller 8 in parallel. . The paper type detector is a light emitting diode 7 on the light emitting side of the reflective photo interrupter.
a and the light receiving element 7b on the light receiving side detect the amount of reflected light, and the light emitting diode 6a on the light emitting side and the light receiving element 6b on the light receiving side of the transmissive photointerrupter of the paper thickness detection unit detect the amount of transmitted light. is there.

The original 2 sent out from the separating portion is sent to the ADF original glass 9 by the conveying roller 8 after being checked by the double-feed detecting portion whether or not it is double-fed. The document sent to the ADF document glass 9 is illuminated by the light source 11 and the reflecting plate 12, and the reflected light is reflected by the first mirror 13 and the second carriage base 17 which are held and fixed by the first carriage base 14.
The CCD 18 on the image reading plate 20 is moved by the lens 18 through the second mirror 15 and the third mirror 16 which are held and fixed by the lens 18.
9 and the information on the original is read. The read document 2 is sent to the paper discharge roller 10 and is discharged to the paper discharge tray 21.
Discharged on top.

The information from the two sensors of the double feed detection unit is
The amount of transmitted light from the paper thickness detection unit corresponding to the amount of reflected light from the paper type detection unit is recorded in the control device (not shown) as reference data. When the original 2 that has been conveyed is the second and subsequent sheets,
The information from the two sensors and the information recorded in the control unit are compared to determine the double feed.

FIG. 2 shows the details of the paper thickness detection unit by the transmission type sensor and the paper type detection unit by the reflection type sensor. The paper thickness detection unit arranges the light emitting diode 6a above the upper guide plate 22 of the document conveyance path and the light receiving element 6b below the lower guide plate 23, and detects the amount of transmitted light of the original 2 passing therethrough, thereby detecting the original. 2 thickness is detected. Further, the paper type detection unit is provided on the upper side of the upper guide plate 22 with the light emitting diode 6a of the paper thickness detection unit.
The light emitting diode 7a and the light receiving element 7b are arranged with the
The paper type of the document is detected by detecting the amount of reflected light of the document 2 passing through.

The light emitting diode 7a and the light receiving element 7b of the paper type detecting device are sandwiched by the light emitting diode 6a of the paper thickness detecting device.
Since these two detecting devices are arranged on the original 2
The same range can be detected simultaneously. That is, in the paper thickness detection and paper type detection, if there is printing etc. in the detection range, the amount of transmitted light and the amount of reflected light will decrease, and false detection of double feeding will occur. The focus is on the fact that a restriction such as printing is set in (for example, a range of 10 mm × 10 mm). The upper guide plate 22 and the lower guide plate 23 are provided with holes 22a and 23a for detecting the paper thickness by the paper thickness detecting device and detecting the paper type, respectively.

FIG. 3 is a diagram conceptually showing double feed detection in the present invention. In the case of thin paper, the amount of reflected light is small regardless of the number of sheets, and the amount of transmitted light changes greatly depending on the number of sheets. On the other hand, in the case of plain paper, the amount of reflected light is larger than that of thin paper and the amount of transmitted light is equal to about 5 sheets of thin paper. Is a general trend. Then, since the amount of transmitted light for one sheet of plain paper and the amount of transmitted light for five sheets of thin paper are equal, it is determined that the above-described conventional technique does not perform double feeding. However, according to the present invention, since the output values of the reflected light amount and the transmitted light amount as described above are recorded, if the thin paper is conveyed and the reflected light amount is the same as that of one plain paper, the thin paper is double-fed. It can be judged that it has been done.

The operation of this embodiment will be described with reference to the flowchart of FIG. When the paper feeding operation is started (step 1), the originals 2 stacked on the paper feeding tray 1 are sent to the separating section by the pickup roller 3, and only one sheet of the separating roller 4 and the reverse roller 5 is transferred to the conveying roller 7. Sent.
The original 2 sent out from the separating section is first detected in its paper type by detecting the amount of reflected light while passing between the light emitting diode 7a and the light receiving element 7b of the paper type detecting section (step 2). ). Then, the thickness is detected by detecting the amount of transmitted light while passing through the light emitting diode 6a and the light receiving element 6b of the paper thickness detecting portion (step 3). Then, using the data of the paper thickness of the same paper type that was conveyed immediately before and in the case of non-double feed, the detected paper thickness of the original 2 is set to ± 20% with respect to the data as a reference range. Double feeding is detected depending on whether it is within the reference range (steps 4 and 5). If it is not a double feed, the detected paper thickness is stored as a new paper thickness reference value for this paper type (step 6).
If it is determined that the multi-feeding is not performed, the feeding roller 8 further feeds the ADF original glass 9 to read the image (step 7). The document 2 after the image is read is discharged onto the paper discharge tray 21 via the paper discharge roller 10, and if there is a next document (step 8), the process returns to step 1 and the subsequent operations are repeated. .

When the double feed is detected, if the paper thickness of the paper type is judged to be out of the reference range in step 5, the feeding is stopped as the double feed (step 9), and the operator is informed of the double feed. An error display as a tightening warning is displayed on the display unit (not shown) (step 10). A warning sound may be generated.

In this operation, since the paper thickness of the same paper type immediately before is used as the reference value, the change due to the temperature characteristic of the sensor can be minimized. That is, even if the same paper type is used, a difference in sensor output may occur between the first original document and the tenth original document due to the temperature rise due to the driving of the sensor itself and the change in ambient temperature. If the paper thickness data of the same paper type is used as the reference value, the difference in the output can be minimized.

Another operation of this embodiment will be described with reference to the flowchart of FIG. In this operation example, the original data of the same paper type conveyed in the past is used, and the average data of the paper thickness in the case of non-double feed is used. Double feeding is detected based on whether or not it is within the range. That is, steps 4 and 6 are different from the operation of FIG.

If it is not a double feed, it is stored as the (n + 1) th sheet thickness data of the same sheet type, and becomes the past (n + 1) th sheet thickness average reference value at the time of detecting the double feeding of the next document. In this operation, since the average of the paper thickness data of the same paper type can be used as the reference value, it is possible to perform the double feed detection without being affected by dust or the like adhering to the sensor surface.

FIG. 6 is a perspective view showing a second embodiment of the present invention in which the arrangements of the paper thickness detecting unit and the paper type detecting unit are different. In the first embodiment described above, the light emitting diode 7a for detecting the paper type and the light receiving element 7b are arranged so as to sandwich the light emitting diode 6a for detecting the paper thickness along the conveyance direction of the original 2. It may be arranged in a direction (main scanning direction of the document) perpendicular to the transport direction. Other configurations and operations are first
The description is omitted because it is the same as the embodiment.

FIG. 7 is a perspective view showing a third embodiment of the present invention in which the configurations of the paper thickness detection unit and the paper type detection unit are different. In the present embodiment, a light emitting diode 6a and a light receiving element 6b, which are transmission sensors as a paper thickness detection device, are arranged on the upstream side in the document conveyance direction, and are separated by a fixed distance, and a light emission diode 7a is a reflection sensor as a paper type detection device. The light receiving element 7b is arranged.

Further, a black sheet material 24 is provided on the lower guide plate 23 which is the background surface of the detection range detected by the light emitting diode 7a and the light receiving element 7b of the reflection sensor, and is emitted from the light emitting diode 7a to the light receiving element 7b. The incident light is
Not only the component reflected from the document surface but also the component reflected from the black sheet material 24 which is the background surface through the document 2 are included. By making the background surface black, the component reflected from the background surface and incident on the light receiving element 7b can be removed.
For example, when several thin paper originals are fed,
Even if the amount of transmitted light is the same for a single sheet, the amount of transmitted light for each amount of reflected light is used for determination, and therefore, it is possible to detect that a thin paper document has been double-fed, and the detection accuracy is further improved. The other configurations and operations are the same as those in the first embodiment, and the description thereof will be omitted.

As the paper thickness detecting unit, in addition to the transparent sensor as in the above-described embodiment, the thickness of the original is changed by using an arm swingable in the conveyance path of the original 2 and a minute angle sensor connected thereto. You can also use a means to detect the
Further, it is also possible to use a means for arranging an ultrasonic wave transmitter and an ultrasonic wave receiver across the conveyance path of the original 2 and detecting the thickness of the original from the attenuation of the ultrasonic wave to the receiving side. Further, in the above-described embodiment, the paper thickness is detected after the paper type is detected, but the paper thickness may be detected first by the reverse.

[0034]

As described above, the paper feeding device according to the first aspect of the invention is provided with the paper thickness detecting means and the paper type detecting means in the conveying path on the downstream side of the separating means in the paper conveying direction. The data of the reference paper thickness corresponding to the type is compared with the information from the paper thickness detecting means and the paper type detecting means to determine whether the paper is in the double feed state. It is possible to make a determination according to the paper type, and it is possible to easily detect double feeding even when sheets of the same size but different paper types (paper qualities) are mixed and continuously conveyed.

As described above, in the paper feeding device of the second aspect, the paper thickness detecting means and the paper type detecting means are arranged so as to detect the same range of the original being conveyed. There is an effect that it is possible to detect the double feeding of the document without increasing the restriction range of printing or the like.

As described above, in the paper feeding device of the third aspect, the paper type detecting means is a reflection type sensor comprising a light emitting diode and a light receiving element, and the light emitting diode and the light receiving element are used for the paper thickness detecting means of the paper. Since the two sensors are arranged so as to be sandwiched in the carrying direction, it is possible to arrange the two sensors in a space-saving manner, and it is possible to prevent the carrying path of the paper from being lengthened and thus prevent the device from becoming large.

As described above, in the paper feeding device according to the fourth aspect, the paper thickness detecting means is a transmissive sensor including a light emitting diode and a light receiving element, and the paper type detecting means is a reflective sensor including a light emitting diode and a light receiving element. The light emitting diode and the light receiving element of the paper type detecting means are arranged so that the light emitting diode or the light receiving element of the paper thickness detecting means is sandwiched in the paper conveying direction, and the background of the paper type detecting range of the paper by the paper type detecting means is arranged. Since the surface is formed of a member having a black surface, the two sensors are arranged at different positions, and even if the same area of the document is detected as the document is conveyed, the paper is detected by the reflection sensor. Since the background of the detection range for detecting the species is black and the influence of light reflected from the background surface and incident on the light receiving element can be removed, there is an effect that more accurate information on the paper type can be obtained.

As described above, in the paper feeding device of the fifth aspect, the means for setting the data of the reference paper thickness stores the data of the paper thickness of the original of the same paper type conveyed immediately before the detecting operation. However, since that data is used as the reference value, even if the output changes depending on the ambient temperature when a light emitting sensor and a light receiving sensor having temperature characteristics in light emitting performance and light receiving performance are used, the same paper type that was conveyed immediately before can be used. By using the paper thickness data of the document as a reference, there is an effect that the change can be minimized and more accurate double feed detection can be performed.

As described above, in the paper feeding device according to the sixth aspect of the invention, the means for setting the data of the reference paper thickness is such that the fixed number of originals of the same paper type conveyed just before the detection operation are performed. Stores the paper thickness data obtained by calculating the average value,
Since the data is used as a reference value, even if dust such as paper dust adheres to the light emitting sensor or the light receiving sensor, or the dust is removed, the output of the light receiving sensor changes,
By using the paper thickness data obtained by calculating the average value as a reference, it is possible to minimize the influence of dust etc. that adheres to the sensor or does not adhere to the sensor, and perform double feed detection with higher accuracy. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing details of a paper thickness detection unit by a transmissive sensor and a paper type detection unit by a reflective sensor.

FIG. 3 is a diagram conceptually showing double feed detection in the present invention.

FIG. 4 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 5 is a flowchart showing another operation of the first embodiment of the present invention.

FIG. 6 is a perspective view showing a second embodiment of the present invention in which the arrangement configurations of the paper thickness detection unit and the paper type detection unit are different.

FIG. 7 is a perspective view showing a third embodiment of the present invention in which the paper thickness detection unit and the paper type detection unit have different configurations.

[Explanation of symbols]

1 Paper tray 2 manuscripts 3 pickup roller 4 Separation roller 5 Reverse roller 6a Light emitting diode (paper thickness detector) 6b Light receiving element (paper thickness detector) 7a Light emitting diode (paper type detector) 7b Light receiving element (paper type detector) 8 Conveyor rollers 9 ADF original glass 10 Paper ejection roller 11 light source 12 Reflector 13 First mirror 14 1st carriage base 15 Second mirror 16 Third mirror 17 Second carriage base 18 lenses 19 CCD 20 Image reading board 21 Output tray 22 Upper guide plate 22a hole 23 Lower guide plate 23a hole 24 Black sheet material

Claims (6)

[Claims] 1. A sheet stacking unit capable of stacking a plurality of sheets such as originals and transfer sheets, a sheet feeding unit for feeding sheets stacked on the sheet stacking unit, and a sheet to be fed from other sheets. In a sheet feeding device provided with a separating means for separating and a double-feed detecting means for detecting double-feed of two or more sheets, the double-feed detecting means is provided in a transport path downstream of the separating means in the sheet transport direction. And a paper type detection means, and a control means for processing information from the double feed detection means is provided, and the control means records data of a reference paper thickness corresponding to the paper type of the paper. Means, means for comparing the reference data with information from the double feed detecting means, and double feed determining means for determining whether or not the sheet is in the double feed state, wherein the double feed determining means detects the paper thickness. The paper thickness data of the paper being conveyed and the paper type detection means A paper feeding device, characterized in that it is judged whether or not a document being conveyed is double-fed by using the output paper type data of the paper being conveyed. 2. The paper feeding device according to claim 1, wherein the paper thickness detecting means and the paper type detecting means are arranged so as to detect the same range of a document being conveyed. Paper equipment. 3. The paper feeding device according to claim 1,
A paper feed characterized in that the paper type detection means comprises a reflection type sensor consisting of a light emitting diode and a light receiving element, and the light emitting diode and the light receiving element are arranged so as to sandwich the paper thickness detection means in the sheet conveying direction. apparatus. 4. The sheet feeding device according to claim 1,
The paper thickness detecting means includes a transmissive sensor including a light emitting diode and a light receiving element, the paper type detecting means includes a reflective sensor including a light emitting diode and a light receiving element, and the light emitting diode and the light receiving element of the paper type detecting means. Is disposed with the light emitting diode or the light receiving element of the paper thickness detection means sandwiched in the paper transport direction, and the background surface of the paper type detection range of the paper by the paper type detection means is formed of a member having a black surface. A paper feeding device characterized by the following. 5. The sheet feeding device according to claim 1, wherein the means for setting the reference paper thickness data sets the paper thickness data of an original of the same paper type conveyed immediately before the detection operation. A sheet feeding device, which stores the data and uses the data as a reference value. 6. The paper feeding device according to claim 1, wherein the means for setting the reference paper thickness data sets a fixed number of originals of the same paper type conveyed immediately before the detection operation. A sheet feeding device, which stores data of a paper thickness obtained by calculating an average value and uses the data as a reference value.