JPH0679947B2 - Overlap detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting overlap feeding of sheets in a conveyance mechanism in a conveyance type scanner or the like.

[Conventional technology]

In a conveyor type scanner that takes out a plurality of stored sheets of paper one by one and conveys them, and scans the image on the paper during the conveyance, in order to ensure accurate scanning of all sheets It is required to provide a device that can detect the case where two or more sheets are fed at one time.

Such an overlapped feeding detection device focuses on the fact that the amount of transmitted light in a white background portion of the paper differs between the case where there is one sheet of paper and the case where two or more sheets overlap, and the amount of transmitted light in a white background portion of the paper is different. It is conceivable that the presence / absence of the overlapped feeding is determined depending on whether or not exceeds a certain light amount range. Actually, in the OCR (optical character reading device), one measuring means for measuring the amount of transmitted light at a specific place corresponding to a white background on the paper is provided in the device, and based on the measurement result of the measuring means. It is performed to detect the overlap feed.

However, in the case of the transport type scanner, unlike in the OCR, whether a certain location on the transported paper corresponds to a white area or a black printed area. Is not constant between each sheet. Therefore, when using the above-mentioned detection method in OCR in a conveyance type scanner, the measurement location may happen to coincide with the location corresponding to the printed portion, and due to this, the amount of transmitted light decreases. However, it may be erroneously determined that there is overlap feed even if overlap feed has not occurred.

Therefore, in the transport type scanner, it is not appropriate to use the above detection method as it is. And other suitable detection devices that can be used in the carrier type scanner have not existed in the past.

[Problems to be solved by the invention]

Therefore, it has been difficult for the transport type scanner to perform highly accurate detection of the overlapped feeding.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a stacking feed detection device suitable for use in a conveyance type scanner.

[Means for solving problems]

The overlap feeding detection device according to the present invention irradiates the conveyed paper with light over a measurement range of a certain length, respectively, and measures the amount of light transmitted through the paper, and A measuring means consisting of a plurality of independent measuring sections arranged in parallel to each other, and for extracting the transmitted light quantity at a plurality of locations from among the transmitted light quantity in each measurement range for each of the measuring sections. , Extractor for randomly extracting the transmitted light amount at each of the different measurement units along the transport direction at random, and based on the transmitted light amount at the plurality of positions, the presence / absence of overlapping feeding of the sheets is determined. The quantity of transmitted light at a predetermined number or more of the quantity of transmitted light at a plurality of locations extracted from the quantity of transmitted light within the measurement range of one of the measuring units is a predetermined light quantity range. When located within, it determines that there is no overlap feed, natural Lazar time, is characterized in that comprises a determination means that there is overlap feed.

[Action]

When the sheet is conveyed, each measuring unit measures the amount of transmitted light over a measuring range of a certain length on the sheet, and the extracting unit extracts the amount of transmitted light at a plurality of points in each measuring range. The determining means determines whether or not the sheet is overlapped and fed based on the amounts of transmitted light at the plurality of locations.

Here, since the measurement is performed by the measuring means composed of a plurality of independent measuring units arranged in parallel with respect to the transport direction, the measurement range happens to cover the entire printed portion (for example, ruled lines extending in the transport direction of the paper). The probability of matching the applicable range is very small. In addition, since the transmitted light quantity is extracted at multiple points within one measurement range, it is possible that all or most of the extracted points within the same measurement range will be the same as the printed section. Is much smaller than the possibility that if there is only one measurement point, the point will coincide with the point corresponding to the printed portion.

As described above, since it is very unlikely that all or most of the positions serving as the judgment reference parts of the judging means coincide with the parts corresponding to the printed portion, the judgment means causes the matching. It is possible to greatly reduce the possibility that an erroneous determination will occur. Therefore, by using this detecting device, it is possible to improve the accuracy of detecting the overlapped feeding in the conveyance type scanner and the like.

When the extracting means extracts the transmitted light amounts at different points in the transport direction for each measurement range, the extracted points in different measurement ranges have the same printed portion (for example, the sheet transport direction). The ruled line that extends in the direction perpendicular to is not matched with the part corresponding to the ruled line. Therefore, it is possible to further reduce the possibility of erroneous determination in the determination means, and to further improve the accuracy of detecting the overlapped feeding in the conveyance type scanner or the like.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic view of an example of a conveyance type scanner using the overlapped feeding detection device according to the present invention, omitting portions not directly related to the present invention. In this transport type scanner 1, two photo sheets are sandwiched at a certain position X on the transport path of the paper 2 taken out from a storage means (not shown) and transported by a transport mechanism (not shown). Sensors 3 and 4 are provided. The photosensors 3 and 4 respectively irradiate light over the entire length of the sheet 2 passing through the position X as shown in FIG. 2, sample the light transmitted through the sheet 2 at a predetermined sampling period, and calculate the amount of light. To measure. Data indicating the amount of transmitted light measured by the photosensors 3 and 4 are stored in the memories 5 and 6, respectively. The data stored in the memories 5 and 6 is read by the microcomputer 7. The microcomputer 7 serves as an extraction unit and a determination unit.

The carrying type scanner 1 is provided with means for selecting either execution or prohibition of the overlap feeding detection processing by the detection device. However, since such means can be easily realized by a known technique, description thereof will be omitted.

Next, an example of the overlapped feed detection processing by this detection device is as follows.

When the first sheet 2 is conveyed by the conveying mechanism and passes the position X, and the data indicating the amount of transmitted light measured by the sensors 3 and 4 is stored in the memories 5 and 6, the microcomputer 7
As shown in FIG. 3, in step 101, it is determined whether the sheet 2 is the first sheet. Then, the determination is YES and the process proceeds to step 102.

In step 102, the transmitted light amount data is read from the memories 5 and 6, and the largest light amount L of the light amounts transmitted through the first sheet 2 is obtained from the data. Then, based on the light amount L thus obtained and the thickness of the paper 2, the light amount range L _{MAX to} L _MIN that can be recognized as the light amount that is transmitted through one sheet 2 is determined (L is one example. _MAX = 1.2L, L _MIN = 0.8L).
Upon completion of step 102, the process returns to step 101.

When the next sheet 2 is conveyed by the conveying mechanism and passes the position X, and the data indicating the amount of transmitted light measured by the sensors 3 and 4 is stored in the memories 5 and 6, the microcomputer 7
This time, NO is determined in the step 101, and the process proceeds to the step 103.

In step 103, as shown in FIG. 2, the length l _D (excluding the area of a certain length l _O (for example, about 69 mm in the case of A4 size) from the total length l of the sheet 2 is excluded. = 1-2
Read the amount of transmitted light in the judgment area (l _O ), from the memories 5 and 6 (excluding both ends, erroneous judgment as to whether or not there is overlap feed due to the binding holes often provided at the edges of the paper. This is to avoid that). Then, from the data read from the memory 5, a plurality (for example, A4
In the case of the size paper, the data at the location a in 35) is randomly extracted, and the data at the same location b is randomly extracted from the data read from the memory 6. (As a result of performing such random extraction,
With respect to the data read from the memory 5 and the data read from the memory 6, as shown in FIG. 2, data at different points a and b in the transport direction are extracted. ) Subsequently, in step 104, a predetermined number or more of the transmitted light amounts indicated by the data at each location a (1 or more, but from the viewpoint of noise countermeasures, 5 or more as an example in the case of A4 size paper) It is determined whether the transmitted light amount is within the light amount range L _{MAX to} L _MIN determined in step 102. If YES, the process proceeds to step 105, it is determined that there is no overlap feeding, and then the process returns to step 101. If NO, go to step 106.

In step 106, the amount of transmitted light at a predetermined number or more of the transmitted light amounts indicated by the data at each position b is
It is determined whether the light amount is within the range L _{MAX to} L _MIN .
If YES, the process proceeds to step 105, it is determined that there is no overlap feeding, and then the process returns to step 101. If NO in this case as well, the routine proceeds to step 107, where it is determined that there is overlap feeding, and then the routine returns to step 101.

Hereinafter, the same processing is repeated for each sheet 2 that is transported by the transport mechanism and passes through the position X, and the overlapped feeding is detected.

Although two photosensors are provided as the measuring means in this embodiment, three or more photosensors may be provided.

〔The invention's effect〕

As described above, according to the overlap feeding detection device of the present invention, it is possible to detect the overlap feeding of sheets in the conveyance mechanism with high accuracy in the conveyance type scanner or the like.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing an example of a conveyance type scanner using the overlapped feeding detection device according to the present invention, and FIG.
FIG. 1 is a plan view showing a portion to be irradiated with light from each sensor on a sheet that has passed a position X in the figure, a judgment area on the sheet, and a portion to be extracted with transmitted light amount data in the judgment area. 3 is a flowchart outlining an example of a program executed by a microcomputer therein. 1 ... Conveyor type scanner, 2 ... Paper, 3,4 ... Photosensor, 5,6 ... Memory, 7 ... Microcomputer.

Claims (1)

[Claims] 1. A method for irradiating a conveyed sheet with light over a measuring range of a certain length and measuring the amount of light transmitted through the sheet, respectively, in parallel with the conveying direction. Measuring means consisting of a plurality of independent measuring units arranged, for extracting the transmitted light amount at a plurality of locations from among the transmitted light amount in each measurement range for each measuring unit,
Extraction means for randomly extracting the transmitted light amount at each of the different randomly measuring parts along the transport direction, and based on the transmitted light amount at the plurality of positions, for determining the presence or absence of overlap feeding for the paper Is, when the amount of transmitted light at a predetermined number or more of the transmitted light amount at a plurality of locations extracted from the amount of transmitted light within the measurement range of any one of the measurement units is within a predetermined light amount range,
A multi-feed detecting device comprising: a determination unit that determines that there is no multi-feed and determines that there is multi-feed when there is no such situation.