JP2004043192A - Transport device for paper sheets - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of wrinkles and bending by smoothing the surface of a paper sheet brought into contact with a belt having a low coefficient of friction in transporting the paper sheet. <P>SOLUTION: All of transport belts are set to be driven at the same speed, and a means for detecting the passing time of the paper sheet and a means for detecting the length of the paper sheet are provided in front and in the rear of a transport path bent by the transport belt. When these values are more than designated values, multi-feed of paper sheets is decided. <P>COPYRIGHT: (C)2004,JPO

Description

{Circle around (1)} The present invention relates to a sheet conveying device used for a sheet sorting device or the like, and relates to a device for detecting overlap of conveyed objects.

(4) In a sheet sorting apparatus, it is required that only one sheet is separately transported due to the nature of the apparatus. As this type of device, for example, there is a postal letter sorting device, but with this device, double feeding of postcards and envelopes causes erroneous sorting, jams, pain in postal letters, and the like. For this reason, the sorting apparatus has conventionally been provided with a double feed detection device for the conveyed articles.

一 つ One of the conventional examples is disclosed in JP-A-7-10322. This apparatus includes a shift transport unit including two drive rollers and a transport belt stretched over the two drive rollers, and a sheet length measuring sensor provided in the shift transport unit. The diameter of the drive pulley is changed so that the rotational speed of the drive roller is different in the shift conveyance unit. For this reason, a speed difference occurs in the transport belt, and when the overlapped paper sheets are transported through the shifted transport unit, the paper sheets are shifted in the transport direction. The length is detected by the length measuring sensors for the paper sheets provided before and after the shifting conveyance unit, and the number of sheets conveyed is determined based on the length measurement results before and after the passing of the shifting conveyance unit. It is to determine whether or not.

従 来 In addition, many of the conventional paper sheet transporting apparatuses transport the paper sheet while holding the paper sheet with a transport belt. The coefficient of friction of the conveyance belt on the conveyance surface side is set to a large value of 0.5 or more in order to reduce slip between the paper sheet and the conveyance belt.

(4) In the above-mentioned paper sheets double feed detecting device, the speed of the endless conveyor belt for holding and conveying the sheets is different. However, if the speed difference is forcibly provided in the conveying belt means, for example, when a letter of an envelope having a small paper thickness is conveyed, the speed of the conveying belt contacting one surface and the other surface is different. Wrinkles occur on letters, sometimes causing transport jams. Further, since the letters themselves are wrinkled, when the letters are stored in a stack, the subsequent letters are caught by the wrinkles, which may cause an accumulation failure. Further, in the above-described prior art, there is a problem that the configuration is complicated because a means for varying the speed of the transport belt is required for detecting the double feed. For this reason, if a plurality of multi-feed detections are required, a means for varying the speed of the transport belt by the number of the detections is required, resulting in an increase in cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper sheet conveying apparatus capable of preventing a surface in contact with a belt having a low coefficient of friction from slipping when a letter is conveyed and preventing wrinkles and bending from occurring. It is in.

The above-mentioned object is to provide a conveyor belt means which is arranged so as to be in contact with each other so as to be in contact with each other, and which conveys paper sheets by sandwiching them between the opposing surfaces, and a drive for driving these conveyor belts so as to have the same speed. Means, the friction coefficient of the surface of one of the opposed conveyor belts that comes into contact with the paper sheet has a friction coefficient of the surface of the other conveyor belt that comes into contact with the paper sheet. This is achieved by being smaller than the coefficient.

ADVANTAGE OF THE INVENTION According to this invention, when a letter is conveyed, the surface which contacts the belt with a low coefficient of friction becomes slippery, and can provide the conveyance apparatus of the paper sheet which can prevent generation | occurrence | production of a wrinkle or a bend. .

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a description will be given using a device that handles postal letters such as postcards and sealed letters.

FIG. 1 shows a letter conveying device using the sheet multi-feed detecting device of the present invention. This device conveys a letter 8 inserted from an entrance I to an exit O. The conveying path of this letter conveying device includes endless belts 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H as conveying means, pulleys 2A, 2B, 2C, 2D, 2E for driving these belts. 2F, 2H, and a plurality of rollers 3 around which these belts are wound. The transport belt is driven by driving the pulley from a motor 4 as a drive source via a power transmission belt 5. At this time, the diameters of the pulley 4A of the motor and the pulleys 5A, 5B, 5C, 5D, 5E, 5F, 5H for transmitting the driving force are set so that the speeds of the transport belt 1 are all the same. In the present embodiment, the conveyor belt 1G is driven by contact with the conveyor belt 1F. Further, passage sensors 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j, 6k, 6l for detecting passage of a letter are provided in the transport path. These passage sensors 6 are connected to the control unit 7, and the shift detection unit 71 and the multi-feed determination unit 72 of the control unit 7 calculate the passage time or letter length of the letter 8 and compare the passage time and letter length. Then, the multifeed is determined based on the comparison result.

Next, a method of detecting a double feed will be described with reference to FIGS. FIG. 3 shows a section 1 shown in FIG. 2 in the case where a belt having an axial load of about 1.3 (kgf / cm width) at the time of 5% elongation is used as the transport belt in the letter-shaped transport apparatus shown in FIG. Shows the total sum of the amount of corners of the transport belts 1A, 1C, 1E, and 1G on the letter B side with respect to the transport belts 1B, 1D, 1F, and 1H on the letter A side in each section from to. is there. That is, in section 0, the advance amount of the transport belt 1A with respect to 1B, in the sections 1 and 2, the advance amount of the transport belt 1C with respect to 1D, and in the sections 3 and 4, the advance amount of the transport belt 1E with respect to 1D, In section 5, the amount of advance of transport belt 1E with respect to 1F, in sections 6 and 7, the amount of advance of transport belt 1G with respect to 1F, in section 8, the amount of advance of transport belt 1E with respect to 1F, and in section 9 the amount of advance. The advance amount of the belt 1E with respect to 1H is shown, and in the sections 10 and 11, the advance amount of the transport belt 1C with respect to 1H is shown. As can be seen from FIG. 2, although the transport belts are driven to have the same speed, there is a shift between the transport belts due to a local speed difference.

FIG. 4 shows the variation in the length of a letter when a government-made postcard and a 1-mm-thick fixed-form envelope letter are conveyed in the conveying state shown in FIG. However, in this example, the letter A shown in FIG. 1 is an official postcard, and B is a 1 mm envelope letter. As can be seen from the results of FIG. 4, it can be seen that the length of the overlapped letters varies in each section. As can be seen from FIG. 3, this variation is particularly large near the inflection point of the advance amount of the other belt with respect to the other belt. That is, it can be said that the larger the change in the local speed of the other belt with respect to the one belt, the larger the deviation.

で は The present invention utilizes this point to detect double feed. A plurality of letter passage sensors 6 provided on the conveyance path detect passage of the letter 8 and transmit a passage signal to the control unit 7. The shift detecting unit 71 of the control unit 7 detects the change in the length of the letter shown in FIG. 4 as a change in the transit time signal from the pass sensor 6, and detects the change in the double feed determining unit 72. For a value exceeding a predetermined value (predetermined value), the double feed of the letter 8 is determined and a double feed detection signal is generated. Then, the control unit 7 issues a command for performing subsequent processing such as excluding the letter, for example.

5. That is, as shown in FIG. 5, for example, the passage sensor 6a is used as a reference passage sensor (second detecting means), and the passage time T1 calculated from the letter passage signal from this sensor is stored (step 10). Next, a passage time T2 calculated from a letter-like passage signal from a passage sensor such as the passage sensor 6b in the next step is stored (step 120). Further, the control unit calculates the difference ΔT between the passing times T1 and T2 (step 130), and determines whether or not this value is larger than a predetermined time ΔT * (step 140). It is determined that the letters being conveyed are being sent in an overlapping manner (step 150), and if not, it is determined that the letter is one letter (step 160).

When performing this determination work, for example, 6a in FIG. 1 may be determined as the reference pass sensor, and the pass sensors on the next process side may be sequentially changed as 6b and 6c as the comparison pass sensors, or the letter may be conveyed. Accordingly, the reference pass sensors may be 6a, 6b, 6c, and the comparative pass sensors may be correspondingly, for example, 6b, 6c, 6d and pass sensors on the downstream side of the reference pass sensors.

(4) In the above-described embodiment, an apparatus using a relatively easy-to-extend belt is shown, but the present invention is not limited to an apparatus using an easily-expandable belt as a transfer belt. Means for generating a speed difference between the conveyor belts include, in addition to the above, belts having different Young's moduli, belts having different friction coefficients of the conveyance surface, and winding angles of the drive belt around a pulley shaft for driving the conveyance belt having different angles. There are means such as doing. This is exactly the same in the following embodiments.

FIG. 6 shows another embodiment of the apparatus for detecting double feed of paper sheets according to the present invention. The conveyance path of the letter conveyance device in the double feed detection device is bent, and endless belts 1I and 1J as conveyance means are driven by pulleys for driving these belts, and a roller 3 around which these belts are passed. Be composed. Further, the transport belt is driven by driving the pulley from a motor as a drive source via a power transmission belt. Passage sensors 6m and 6n that detect passage of a letter are provided at the entrance and the exit of the bent conveyance path. These passage sensors are connected to a control unit, and the control unit performs calculation of the passage time or the length of the letter, comparison of the passage time and the length of the letter, and determination of the double feed based on the comparison result. In the transport path shown in FIG. 6, the transport belts 1I and 1J are driven at exactly the same speed. However, when letters 8C and 8D (displacement amount d1) overlapping this transport portion as shown in FIG. 6 are transported, the curvature radii R1 and R2 at which each letter is bent differ due to the influence of the thickness of the letter. For this reason, the letters on the inside and outside of the bent portion are shifted as shown in FIG. 7 so that the letters on the outside are delayed. The shift amount at this time is d2. The passage sensors 6m and 6n detect the passage time of the letter and transmit a signal to the control unit. The control unit regards the variation d2-d1 of the length of the letter at the entrance and the exit of the curved conveyance path as variation of the transit time signal from the passage sensors 6m and 6n, and sets the variation to a predetermined value. If the number exceeds the limit, a double feed of the letter is determined, a double feed detection signal is generated, and the subsequent processing is performed.

FIG. 8 is a configuration diagram showing an embodiment of a postal letter sorting apparatus using the sheet multi-feed detection and sheet conveying apparatus of the present invention. In FIG. 8, reference numeral 11 denotes supply means capable of holding a plurality of letters 12 in an upright position. Reference numeral 13 denotes a supply means which is supported along the supply means 11 so as to be movable at equal intervals in the direction of arrow A. This is transfer means capable of moving the letter 12 in the direction of arrow A. Reference numeral 14 denotes a separation unit that can separate only the rightmost one of the letters 12 placed on the supply unit 11 and convey it downward. Such a letter-type separating means is generally a suction type using a vacuum suction belt. The vacuum chamber 15 is negatively pressed to suction the letter 12 onto the suction belt 16, and the suction belt 16 is, for example, a motor. By rotating using the driving means, only the rightmost one of the letters 12 can be separated and conveyed.

# 17 is a conveying means for conveying the letter 12. In the conveying means 17, the letter 12 separated by the separating means 14 is conveyed while being sandwiched between endless belts. Reference numeral 18 denotes a posture correcting unit that can correct the position and inclination of the letter. Reference numeral 19 denotes reading means for reading section information, such as a bar code, attached to the letter 12 in advance. Reference numeral 20 denotes an accumulating means for accumulating the letters 12 from which the sorting information has been read, which is provided near and above the supply means 11. The inside of the stacking means 20 is divided into, for example, 16 stacking sections, and each of the stacking sections can hold the letter 12 substantially upright. Reference numeral 21 denotes a distributing unit that distributes the letter 12 to any one of the accumulating units of the accumulating unit 20 according to the sorting information read by the reading unit 19. Reference numeral 22 denotes a reject accumulation box for accumulating the letters 12 not accumulated in the accumulation means 21.

{Circle around (3)} 23 is a passage sensor for detecting the passage of the letter 12 to be conveyed, and is provided at a plurality of places on the conveyance path. The passage sensor is connected to the control unit 24. The control unit 24 calculates the passage time or the length of the letter 12 and compares the passage time and the length of the letter 12, and performs the work of judging the double feed based on the comparison result.

In the sorting device of this postal letter sorting device, the length of all letters supplied from the supply means 11 is detected by the passage sensor 23 as in the device shown in FIG. A decision to send is made. Then, for a letter determined to be a double feed, a signal to convey the letter to the reject stacking box 22 is sent from the control unit 24 to the distribution means 21, and the corresponding letter is rejected.

In the postal letter sorter shown in FIG. 8, a part of the endless belt as the transport means 17 has a coefficient of friction of 0.5 or less on the contact surface with the letter on the transport belt that is opposed to and contacts the transport belt. Such a belt may be used. For example, in FIG. 8, the conveyance belt 17A forms a double feed detection conveyance path as a belt having a smaller coefficient of friction than 17B, and the control unit 24 determines the double feed based on the letter passing time signals from the passage sensors 23A and 23B. Do the work. With this configuration of the transport belt, the overlapped paper sheets are easily shifted from each other, and it is easy to determine the double feed.

By the way, as described above, even if the conveying belts as conveying means are set to have the same speed, there is a relative speed difference between the conveying belts. For this reason, wrinkles due to the speed difference of the conveyor belt are likely to occur as shown in FIG. 9 particularly in envelope letters having a small paper thickness, and as shown in FIG. 10 for letters having a wide width and a relatively thin paper thickness. Bending occurs at a sharp bend.

原因 The cause of the bending as shown in FIG. 10 will be described with reference to FIG. When the speed of the conveyor belt 1L shown in FIG. 11 is higher than the speed of the conveyor belt 1K, the letter is deformed like 8E due to this speed difference. Further, when the letter is conveyed to the bent portion as shown in FIG. 11 in this state, the letter is bent inward so as to stick to the conveyance belt 1K or the conveyance guide 9 as shown in FIG.

発 生 The occurrence of wrinkles not only damages the letter but also causes the accumulation to be defective due to the subsequent letter being creased during the accumulation. Further, the bending shown in FIG. 10 causes a transport jam.

These problems can be solved by using one of the conveyor belts having a coefficient of friction of 0.5 or less on the contact surface with the letter of the conveyor belt that is in contact with the conveyor belt. That is, when the letter is conveyed, the surface in contact with the belt having a low coefficient of friction becomes slippery, thereby preventing the occurrence of wrinkles and bending.

FIG. 1 is a diagram illustrating an embodiment of a double feed detecting device for paper sheets according to the present invention. FIG. 2 is a diagram showing a transport section in the apparatus shown in FIG. 1. FIG. 2 is a diagram illustrating a shift of a transport belt in the apparatus illustrated in FIG. 1. FIG. 2 is a diagram illustrating an example of an overlapped letter shift in the apparatus illustrated in FIG. 1. The figure which showed one Example of the double feed detection method of the paper sheet of this invention. The figure which showed other Example of the double feed detection apparatus of the paper sheet of this invention. FIG. 7 is a diagram illustrating a detection method of the sheet multi-feed detection device illustrated in FIG. 6. The figure which showed an Example of the sorting apparatus of the postal letter using the sheet double feed detection apparatus of this invention. The figure which showed the generation | occurrence | production of the wrinkle of the letter in the conventional letter transport apparatus. The figure which showed the bending of the letter in the conventional letter transport apparatus. FIG. 11 is a view showing a state in which the letter shown in FIG. 10 is bent.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Conveying belt, 2 ... Driving pulley, 3 ... Roller, 4 ... Motor, 5 ... Power transmission belt, 6 ... Passing sensor, 7 ... Control part, 8 ... Letter, 9 ... Conveyance guide, 11 ... Supply means, 12 ... Letters, 13 ... Transfer means, 14 ... Separation means, 15 ... Vacuum chamber, 16 ... Suction belt, 17 ... Convey means, 18 ... Position correcting means, 19 ... Reading means, 20 ... Collecting means, 21 ... Distributing means, 22 ... Reject accumulation box, 23: passage sensor, 24: control unit.

Claims (1)

A transport belt means is disposed so as to be in contact with each other so as to be in contact with each other, and transports paper sheets sandwiched between the facing surfaces, and a drive means for driving these transport belts so as to have the same speed. In the sheet conveying device, the friction coefficient of the surface of one of the opposing conveying belts that contacts the sheet is smaller than the friction coefficient of the surface of the other conveying belt that contacts the sheet. A paper sheet conveying device characterized by the above-mentioned.

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