JPH0454762A - Original reader - Google Patents

Abstract

PURPOSE:To easily detect the width of paper with high accuracy by inputting a picture signal outputted from a picture information read means to a counter means via a gate when the arrival of paper is detected and inputting a picture element number counted by the count means to a comparator means to detect the width of the paper of an original. CONSTITUTION:A paper tip detection means 22 detects it that an original reaches a read position 99 and a picture information read means 21 reads the original and also a signal from a paper width detection means 20. A count means 24 counts an interval of a couple of signals from the paper width detection means 20 included in the read picture information as a picture element number. A comparator means 26 compares the counted picture element number with a reference value 25 set to a picture element number of paper sheets of prescribed width of at least one kind or over to detect the paper width of the original. Thus, the width of the paper of the original in a picture input device is detected automatically with high accuracy.

Description

[Detailed Description of the Invention] [Summary] Regarding a document reading device with an automatic paper width detection function used for image input, the purpose is to automatically detect the paper width of a document with high accuracy, A document reader comprising: a paper guide that regulates the document paper from both ends; paper leading edge detection means that detects that the document has reached a reading position; and image information reading means that reads image information from the transmitted document at the reading position. In the device,
a paper width detection reference section that is provided in a pair at the tip of the paper guide, covers the image information reading means, and outputs an image signal having a density determined by a predetermined darkness value as a read signal; and the paper width detection reference section. A counting means for counting the interval between a pair of image signals read from a pair of image signals as the number of pixels, and a comparing means for comparing the counted number of pixels with a reference value, and at least one type of reference value in the comparing means is provided. The number of pixels of a sheet of predetermined width is set, and when the paper leading edge detecting means detects the arrival of the paper, the image signal outputted by the image information reading means is inputted to the counting means via a gate, and the counting means The paper width of the document is detected by inputting the counted number of pixels to the comparing means.

[Industrial application field]

The present invention relates to a document reading device having an automatic paper width detection function used for image input.

[Conventional technology]

In conventional document conveying type image input devices, in order to automatically detect the width of the input paper, a document width sensor 94 is conventionally installed in front of the reading position 1t99 in the paper traveling direction, as shown in FIG. The width of the paper is detected before reading the document.

As shown in FIG. 5, a plurality of original width detection sensors are provided in the paper width direction to detect the presence or absence of paper at each position.

The sensor used here is an optical sensor or a mechanical sensor such as a lever switch.

Then, the width of the paper was determined by combining the outputs of each sensor.

The diagram shown in FIG. 5(a) shows the case where the document width sensors are arranged with the central axis as a reference, with the document width sensor S1 in the center,
Document width sensor S2. Paper size is A6 from the center of S3
In this case, the presence of paper is not detected, and if the paper size is A5, the presence of paper can be detected at a distance (5.3 to 7.5 mm from the center).
4 cm), and document width sensor S4. Set S5 at a distance from the center that does not detect the presence of paper if the paper size is A5, and detects the presence of paper if the paper size is A4 (within a range of 7.4 to 10.5 cm from the center). Deploy.

In this way, the document width sensors Sl, S2. S3. S4.35
are arranged, and when the output of each sensor S1 to S5 becomes the output shown in FIG. 5(C), the width of the document is determined.

For example, only Sl is "1" and S2 to S5 are "0"
If so, the document width is determined to be A6.

The diagram shown in Figure 5 (b) shows the case where the document width sensor is arranged with the left side as the reference, and the document width sensor S1 is placed at the distance from the left side reference to A6 (within a range of 10°50 - from the left side reference). Then, set the document width sensor S2 at the distance from the left reference to A6 and A5 (10.5 to 14 mm from the center).
．． Place the document width sensor S3 from the left reference at a distance that does not cover A4 but does not cover A5 (within a range of 14.8 to 21.8 cm from the center). When the output is the value shown in FIG. 5 ((to)), the width of the document is determined.

With such a method, if the width of the document is to be detected in detail, the number of sensors will increase, resulting in an increase in cost.

[Problem to be solved by the invention]

As described above, when attempting to precisely detect the width of a sheet of paper in a document reading device, the number of sensors increases and the logic circuit for determination becomes complex, resulting in an increase in cost.

In view of these points, it is an object of the present invention to provide a means for easily and accurately detecting the width of paper.

(Means for solving gl! problem) The above problem is solved by a document reading device having an automatic paper width detection function configured as follows.

FIG. 1 is a diagram illustrating the principle of the present invention.

A paper guide 12 that regulates the document paper from both ends according to the width of the document, a paper leading edge detection means 22 that detects when the document has reached the reading position 199, and a screen that reads image information from the transmitted document at the reading position 99. In a document reading device equipped with an information reading means 21, a pair of image information reading means 21 are provided at the tip of the paper guide 12 and cover the image information reading means 21, and output an image signal having a density determined by a predetermined threshold value as a reading signal. a paper width detection reference section 20, a counting means 24 for counting the interval between a pair of image signals read from the paper width detection reference section 20 as the number of pixels, and a comparison means 26 for comparing the counted number of pixels with a reference value. At the same time, the reference value in the comparison means 26 is set to the number of pixels of at least one type of paper of a predetermined width, and when the paper leading edge detection means 22 detects the arrival of the paper, the image information reading means 21 The image signal outputted by Gate 2
3 to the counting means 24, and inputting the number of pixels counted by the counting means to the comparing means 26, thereby detecting the paper width of the document.

[For production]

The paper leading edge detection means 22 detects that the original has reached the reading position 99, and the image information reading means 21 reads the paper width detection reference section 20 at the same time as the original.

A pair of paper width detection reference parts 2 included in the read image information
The interval between the 0 signals is counted by the counting means 24 as the number of pixels.

The comparison means 26 compares the counted number of pixels with a reference value set as the number of pixels of at least one type of paper having a predetermined width to detect the paper width of the document.

〔Example〕

1 is a paper width detection reference plate that covers the reading means and is read by the reading means at the same time as the original; 11 is a reading glass stand; 12
81 is a paper guide that holds the position of the paper, 81 is a feed roller that transports the original, 91 is the original a to be read, 92 is a hopper that sets the original, 93 is a stacker that stores the read original, 95 is the reading position Original b, 96 is a lamp used for illuminating the reading position, 97 is a condensing lens at the reading position, 98 is an image sensor for reading the original,
99 is a reading position.

In the figure, a document a91 to be read is first placed in a hopper 92 on the right side, and is held down from the left and right by paper guides 12.

A document a91 is fed to the center by a feed roller 81, reaches a reading position 99, and enters a stacker 93 after being read.

In the figure, a document B95 is placed on the reading glass stand 11, and the reading position is illuminated with a lamp 96 from below the reading glass stand 11.
The light is focused by a lens 97 and read by an image sensor 98.

FIG. 4 provides a detailed explanation of the present invention, and is a diagram showing the original as viewed from the image sensor side at the original reading position.

In the figure, a pair of paper width detection reference plates are sensed by an image sensor with a characteristic density.

The signal read by the image sensor 98 is 0 as shown in Figure (b), and since the paper width detection reference plate is black, the image signal shows a clear recess.The paper width can be determined by counting the interval lO between the recesses in terms of the number of pixels. is detected.

The signal read by the image sensor 98 enters a paper width detection circuit shown in FIG.

The output of the image sensor 98 is sent to the analog-to-digital converter 5.
(abbreviated as ADC), becomes a signal indicating the density level per pixel in 6 to 8 bits, is binarized by the binarization circuit 6, and is entered into the line memory 7.

The output of the line memory 7 enters the guide detection circuit 3, the guide detection circuit 3 detects the continuous black state signal read from the paper width detection reference plate 1, and sends the detection signal to the counting circuit 4. The detection signal is used to count the interval between the paper width detection reference plates 1, and the value is calculated for the specified paper (A4.B5.A).
5. ), a signal indicating the paper width is output.

As explained above, according to the present invention, the paper width can be detected with high accuracy.

Furthermore, with this method, since the image sensor that reads the image and the sensor that reads the paper width are the same, there is an advantage that no misalignment occurs between them.

〔Effect of the invention〕

As is clear from the above description, the present invention has the industrial effect of automatically and accurately detecting the paper width of a document in an image input device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram showing the structure of an embodiment of the present invention, FIG. 3 is a configuration of a paper width detection circuit, FIG. 4 is a detailed explanatory diagram of the present invention, and FIG. The figure shows the arrangement and determination criteria of a conventional paper width sensor, and FIG. 6 shows a conventional document width detection mechanism. In the figure, l is a paper width detection reference plate, 2 is a paper width detection circuit, 3 is a guide detection circuit, 4 is a counting circuit, and 5 is an ADC. 6 is a binarization circuit, 7 is a line memory, 10 is an interval, 11 is a reading glass stand, 12 is a paper guide, 20 is a paper width detection reference section, 21 is an image information reading means, 22 is a paper leading edge detection means, 23 is a gate, 24 is a counting means, 25 is a reference value, 26 is a comparison means, 81 is a feed roller 91, is a document a, 92 is a hopper 93, is a stacker 94, is a document width sensor, 95 is a document sheet, /, 96 is a lamp, 97 is a lens, 98 is an image sensor, 99 is a reading position, Fig. 1 Paper width detection reference plate (black)

Claims (1)

[Claims] A paper guide (12) that regulates the document paper from both ends according to the width of the document, a paper leading edge detection means (22) that detects that the document has reached the reading position (99), and Reading position (
Image information reading means (2) reads image information from the original with
1), in which the paper guide (
The image information reading means (2) are provided in a pair at the tip of the image information reading means (2).
a paper width detection reference section (20) that covers the paper width detection reference section (20) and outputs an image signal having a density determined by a predetermined threshold value as a read signal;
a counting means (24) for counting the interval between the pair of image signals read from the paper width detection reference section (20) as the number of pixels;
Comparison means (26) for comparing the counted number of pixels with a reference value
and setting the reference value in the comparison means (26) to the number of pixels of at least one type of paper of a predetermined width, and when the paper leading edge detection means (22) detects the arrival of the paper, By inputting the image signal outputted by the information reading means (21) to the counting means (24) via the gate (23), and inputting the number of pixels counted by the counting means to the comparing means (26), A document reading device characterized by detecting the paper width of a document.