JP2001341895A - Sheet double-feed detecting method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device capable of stably detecting the double-feed of sheets without being affected by the various thickness, the paper quality and the presence or absence of printing. SOLUTION: The double-feed of the sheets is detected on the basis of the distribution of the diffusion of the light transmitted through the conveyed sheets. This device comprises a light emitting means 2, light receiving means 6 and 7 mounted oppositely to the light emitting means, and a conveying means for conveying the sheets between the light emitting means and the light receiving means. The light receiving means is mounted at least outside of a diffusion area of the light of the light emitting means transmitted through the sheet 1 in a case of one-sheet feeding within a diffusion area (w) of the transmitted light in two-sheet feeding. The double-feed of the sheets is detected by a signal at the reception of the light by the light receiving means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to media such as bills, checks, securities, sheets, certificates, etc. (hereinafter referred to as "paper sheets").
The present invention relates to a sheet multi-feed detecting device for detecting the presence or absence of multi-feed of sheets by detecting diffused light transmitted through the sheet.

[0002]

2. Description of the Related Art Generally, double feed detection of paper sheets is performed by optical detection means using light emitting means and light receiving means.
For example, in the automatic certificate issuing machine shown in FIG.
And a photo sensor C disposed opposite thereto and passes through a transport path D. Here, the transmitted light amount (voltage value) of the light emitting diode B detected by the photo sensor C is compared with a preset threshold value. In the case of the double feed state, the documents are separated into the right chute E and dropped and stored. If not in the double feed state, shoot left as shown by the arrow F
And is placed on the intermediate tray G via the stapler H, bound by the stapler H, and discharged from the discharge port I to the outside.

[0003] A voltage level is set as a threshold value as a basis for judging whether or not double feeding is performed based on received light amount information obtained from a reference sheet. The voltage level of the light receiving element, which changes according to the amount of light transmitted when a sheet passes between the light emitting diode B and the photosensor C, is compared with the threshold value to determine whether or not double feeding is performed. .

However, since the voltage level of the light receiving element that changes according to the amount of light greatly changes depending on the type of sheet, it is necessary to determine the multi-feeding of all sheets with one set threshold value. It is difficult. The amount of transmitted light must be measured for each type of paper, and the threshold for detecting double feed must be changed. For this reason, there are restrictions such as that the paper thickness of the paper sheet is constant, that there is no printing, that the printing is the same, if any, and that the printing is thin enough that the light amount is not affected.

As a technique for solving this problem, Japanese Patent Laid-Open No.
There is an invention described in JP-A-304542. The present invention
In addition to the optical detection means including a light emitting diode and a photo sensor, a paper detection means for detecting paper according to the type of paper, and a double feed detection for setting a mode for determining a double feed detection level of paper to be used. There is provided a level setting means and a calculation means for calculating a threshold value for judging multi-feeding of sheets in the mode set by the multi-feed detection level setting means. The user uses the setting mode of the multi-feed detection level setting means to automatically set a threshold value for determining that the paper to be used is a multi-feed of paper.

[0006]

However, in this apparatus, since the multi-feed is determined by the optical detection means based on the level of the amount of transmitted light, the sheet detection means when one sheet is conveyed to the conveyance path is used. Sampling data is obtained based on the detected result and the result detected by the sheet detection unit when two sheets are conveyed on the conveyance path and the threshold value is calculated by the calculation unit.

As a result, the configuration becomes complicated, and when processing is performed by mixing paper sheets having different thicknesses, there is an inconvenience that the mode setting of the double feed detection level must be frequently switched. . Furthermore, whether the amount of transmitted light in the stack of two thin sheets is the same as that of one thick sheet,
Alternatively, when the number of sheets is one or less, there is a disadvantage that it is no longer possible to detect the double feed of thin paper sheets.

The present invention has been devised in order to solve such a problem of the prior art. Light is applied to a paper sheet, and the spread of diffused light on the back surface is one sheet or two sheets. Focusing on the difference from the above case, instead of performing double feed detection at the level of transmitted light, double feed is determined with the distribution state of transmitted light quantity as the detection target, and different thickness, paper quality, presence or absence of printing It is an object of the present invention to provide a method and an apparatus capable of stably detecting a double feed without being affected.

[0009]

The present invention has the following configuration to achieve the above object. That is, the method of the present invention is characterized in that double feed of sheets is detected based on the diffusion distribution of transmitted light of the conveyed sheets. Specifically, for example, a sheet is conveyed between one light emitting unit and a plurality of light receiving units disposed opposite to the light emitting unit, and the transmitted light of the light emitting unit transmitted through the sheet is transmitted. The light receiving means detects whether the diffusion distribution is the one at the time of single-sheet feeding or the one at the time of double-feeding, and detects double feeding of paper sheets. The light receiving means includes a first light receiving means disposed in a diffusion area of transmitted light transmitted through the paper sheet at the time of single-sheet feeding, and a first light receiving means provided outside the diffusion area of transmitted light at the time of single-sheet feeding. The second light receiving means may be provided in the diffusion area of the transmitted light of the light emitting means which has passed through the paper sheet at the time of feeding two sheets, and the diffusion distribution of the transmitted light may be detected by these means. .

The device of the present invention is characterized in that it has the following configuration. That is, the apparatus of the present invention includes one light emitting unit, a light receiving unit disposed to face the light emitting unit, and a conveying unit that conveys a sheet between the light emitting unit and the light receiving unit. The light receiving means is arranged at least outside the diffusion area of the transmitted light of the light emitting means that has passed through the paper sheet when feeding one sheet and inside the diffusion area of the transmitted light when feeding two sheets. Then, double feed of paper sheets is detected by a signal when the light receiving unit receives light. When the light receiving means is provided in a plurality of diffusion areas, the first light receiving means disposed in the diffusion area of the transmitted light transmitted through the paper sheet at the time of one sheet feeding, and at the time of one sheet feeding And a second light receiving means disposed in the diffusion area of the transmitted light of the light emitting means which has passed through the paper sheet when the sheet is fed by two sheets outside the above diffusion area of the transmitted light. Then, double feed of paper sheets is detected by a signal when the first light receiving means and the second light receiving means receive light.
The detection signal from the light receiving unit is input to, for example, a feeding state detection control unit that detects a feeding state of the paper sheet and controls a next process of the paper sheet. As a light emitting means, a laser beam is typically used.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment in which the present invention is applied to a reader for reading information described on a check. FIG. 1 is a longitudinal sectional view showing a state in which a laser beam is transmitted through one sheet of the present embodiment, and FIG. 2 is a longitudinal sectional view showing a state in which a laser beam is transmitted through two sheets. FIG. 3 is a flowchart of the method of the present invention.

The physical properties relating to the diffusion behavior of a laser beam when the laser beam passes through a check such as a paper sheet will be described. In FIG. 1, reference numeral 1 denotes a check, and reference numeral 2 denotes a light emitting source of a laser beam as a light emitting means disposed above the check 1. The laser beam 3 is applied substantially perpendicular to the paper surface of the check 1. The laser beam 3 has a small spread of light due to the diffraction phenomenon, is excellent in both directivity and convergence, and when passing through the check 1, passes through the check 1 with almost no diffusion. At that time, the diffusion area of the laser beam reaching the back of the check is extremely small (FIG. 1).
The spread area of the diffused light in this case is referred to as a first spread area S.

In FIG. 2, when two checks 1, 1 'are vertically stacked, that is, in the case of double feeding, the transmitted light from the upper check 1 is between the lower check 1' and the lower check 1 '. It is once diffused in the minute void layer 4 as an air layer. When the laser beam 3 scattered by the gap layer 4 passes through the underlying check 1 ′, the degree of diffusion further increases and the lower check 1 ′
Reach the back. The diffusion distribution of transmitted light that reaches the back side is
The spread is much larger than in the case of FIG. 1 in which one check is passed. The spread region of the diffused light in this case is referred to as a second spread region W. As described above, when the laser beam 3 passes through the stacked paper sheets, the transmitted light becomes a diffused light 5 and is diffused.

In an embodiment utilizing this principle, check 1
(In the case of double feed, checks 1 and 1 ') are sent rightward in the figure by a transport device (not shown). A first light receiving element (for example, a photosensor) 6 is provided in the first spread area S so as to face the laser light source 2. Further, inside the second spread area W outside the first spread area S, a first light receiving element 7 such as a photo sensor is disposed in the same second light receiving element 7. A detection signal when these light receiving elements 6 and 7 receive light is input to the feeding state detection control unit 8. The detection output signals from the light receiving elements 6 and 7 can include not only whether or not the diffused light has been received but also information regarding the amount of the diffused light. The feed state detection control unit detects a feed state as to whether or not the sheet is a double feed, and controls the next process of the conveyed sheet. Although not shown, a feed sensor for detecting that the check has been sent by the transfer device is provided in the transfer path. The output signal from the feed sensor is similarly input to the feed state detection control unit 8. The light receiving elements 7 and 10 need not be independent, and a one-dimensional or two-dimensional CCD may be arranged at a position corresponding to the spread range of the diffused light. As a result, the diffusion distribution is accurately detected.

A state in which the apparatus according to the present embodiment detects a double feed will be described with reference to a flowchart shown in FIG. When the power of the reading device is turned on and the transport device including the roller conveyor is operated, a check is sent to the double feed detecting unit.
In the double feed detecting section, the laser beam 3 is emitted from the light source toward the face of the check letter. The laser beam 3 transmits through the check letter surface and forms diffused light on the back surface. At this time, if the number of checks sent by the transport device is one as shown in FIG. 1 described above, only the first light receiving element 6 receives light and outputs a detection signal to the sending state detection control unit 8. Conversely, when the signal from the first light receiving element 6 is input and the signal from the second light receiving element 7 is not input, the feed state detection control unit 8
Recognizes that the feed is normal and causes the next reading unit to convey the check. If no detection signal is input from either the first light receiving element 6 or the second light receiving element 7, a check is not being conveyed to the double feed detecting unit, or the laser beam from the laser light source is properly irradiated. Indicates that it has not been done.

When detection signals from both the first light receiving element 6 and the second light receiving element 7 are input to the sending state detection control unit, the spread distribution when the diffused light of the laser beam transmitted through the check is a double feed. It indicates that there is. Therefore, in this state, the check is in the state of being over-fed, the progress to the next process is stopped, and the process for eliminating the double feed, for example, is automatically forwarded to a route different from the next process transport route, or is transported. Removed from the path. In this way, the present apparatus can determine to what extent the diffused area of transmitted light is distributed according to the position of the light receiving element from which the detection signal is input, thereby making it possible to reliably determine whether or not double feed is performed. Will be detected.

In the above-described embodiment, the light receiving element is arranged in the transmitted light diffusion area S in the case of single-sheet feeding, and it is detected whether the multi-layer feeding or not is performed by comparing the light receiving element with the operating state of the light receiving element in the other area. However, the present invention is not limited to this. For example, the transmission light diffusion region S in the case of two-sheet feed is provided without disposing the light receiving element in the transmission light diffusion region S in the case of one-sheet feed. Whether or not double feed may be performed may be determined based on whether or not the light receiving element disposed in W receives light. In this case, the feed sensor detects and confirms whether or not the sheet has been conveyed to the double feed detecting unit.

Although the present embodiment has been described in detail, the specific configuration is not limited to this embodiment.
Even a design change or the like within a range not departing from the gist of the present invention is included in the present invention. For example, as described above, the light receiving means can not only detect the distribution of the amount of diffused transmitted light, but also use the level of the amount of received light as a determination factor for double feed detection. In addition, the first light receiving element and the second light receiving element do not need to be singly, and a plurality of light receiving elements may be provided. In particular, in the case of the second light receiving element, more accurate double feed detection becomes possible by using a plurality of the light receiving elements in combination with the first light receiving element. Further, any light emitting means other than the laser light emitting source is applicable as long as it is a light emitting means of a parallel light source that optically condenses light having substantially uniform wavelength.

[0019]

According to the method of the present invention, based on the spread distribution of the diffused light transmitted through the paper sheet, the number of the conveyed paper sheet is one.
Since the number of sheets or two or more sheets is detected, the double feed can be detected stably and reliably without being affected by the thickness, the paper quality, or the presence or absence of printing. Further, according to the apparatus of the present invention, there is provided a light-emitting means, a light-receiving means provided at a position facing the light-emitting means, and a transport device, and the position of the light-receiving means is set to a value corresponding to the number of sheets. Since it is arranged in the area, by detecting the diffused light of the transmitted light as the distribution of the diffusion amount, it is possible to reliably and easily detect the presence or absence of the double feed state with a simple configuration.

[Brief description of the drawings]

FIG. 1 is an operation explanatory view showing a state in which a laser beam is transmitted through one sheet of paper in a longitudinal section according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view showing a state in which a laser beam is transmitted through two sheets in a longitudinal section according to the embodiment.

FIG. 3 is a flowchart of a double feed discrimination means in the embodiment.

FIG. 4 is a schematic side view of a conventional device.

[Explanation of symbols]

 1, 1 'check 2 laser light source 3 laser beam 4 air gap 5 diffused light 6 first light receiving element 7 second light receiving element 8 sending state detection control unit 10 second light receiving element

Claims (7)

[Claims] 1. A method for detecting a double feed of sheets based on a diffusion distribution of transmitted light of the conveyed sheets. 2. A spread distribution of transmitted light of a light emitting means which has conveyed a paper sheet between one light emitting means and a plurality of light receiving means disposed opposite to the light emitting means and which has passed through the paper sheet. Detecting the double feed of the sheets by detecting with the light receiving means whether the sheet is a single sheet feed or a double sheet feed. 3. A first light receiving means disposed in a diffusion area of transmitted light transmitted through a sheet when feeding one sheet, and a first light receiving means disposed outside the diffusion area of transmitted light when feeding one sheet. 3. The paper according to claim 2, wherein the diffused distribution of the transmitted light is detected by the second light receiving unit disposed in the diffused region of the transmitted light of the light emitting unit that has transmitted the paper sheet when the sheet is fed by two sheets. A method for detecting double feed of leaves. 4. A light-emitting device, comprising: a light-emitting device; a light-receiving device disposed to face the light-emitting device; and a transport device for transporting paper sheets between the light-emitting device and the light-receiving device. The light receiving means is disposed at least outside the diffusion area of the transmitted light of the light emitting means that has passed through the paper sheet at the time of single-sheet feeding and within the diffusion area of the transmitted light at the time of two-sheet feeding. A multi-feed detection device for paper sheets, which detects multi-feeds of paper sheets based on a signal when the light is received. 5. A light receiving means comprising: a plurality of light receiving means; a first light receiving means disposed in a diffusion region of transmitted light transmitted through a sheet when one sheet is fed; A second light-receiving unit disposed outside the diffusion region of the transmitted light at the time of feeding and disposed within the diffusion region of the transmitted light of the light-emitting unit that has transmitted the paper sheets at the time of two-sheet feeding, A multi-feed detecting device for a paper sheet, wherein the multi-feed detecting device detects a multi-feed of a paper sheet based on a signal when the first light receiving unit and the second light receiving unit receive light. 6. A sheet multi-feed detecting apparatus according to claim 4, wherein a detection signal from said light receiving means is input to detect a sheet feeding state, and the next sheet processing of the sheet is performed. A multi-feed detection device for paper sheets, comprising: 7. The apparatus according to claim 4, wherein said light emitting means is a laser beam.