JPS61166265A - Optical reader - Google Patents

Abstract

PURPOSE:To simplify the structure by obtaining original size information from main scanning information or subscanning information, comparing the original size information with reference original size information stored in advance so as to decide the size of read original thereby eliminating the need for an original size detecting sensor. CONSTITUTION:A lateral picture image signal of an original P read by an image sensor 17 is amplified by an amplifier circuit 23. Then the result is subject to shading correction by a shading correction circuit 25 and subject to binary coding by a binary coding circuit 27. The binary-coded signal is fed to a read processing unit 3 via an interface 29 and fed to a detection circuit 28. The detection circuit 28 obtains the original size information based on the binary- coded signal due to main scanning and subscanning. That is, maximum width among the width information of the original P obtained from the main scanning information is used as the width information of the original P and the presence of original detection is stored at each subscanning and the quantity of detection is used as the length information of the original P. A CPU of a control circuit 31 compares both the size information with the reference original size information stored in advance to decide the size of the read original P.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical reading device such as an image reader capable of detecting the size of a document based on read information.

[Technical background of the invention]

Image processing device For example, in a device that reads an image with an optical reading device such as an image reader and outputs it to a laser printer, etc., when copying by automatically selecting the copy paper size according to the original size, the reading It is necessary to detect the size of the original.

Conventionally, this document size detection has been carried out by embedding a light-emitting element and a light-receiving element in appropriate positions according to the size of the document on the lower surface of a presser plate that holds the document placed on a platen glass, that is, the surface in contact with the document. This is done depending on whether the light receiving element detects the reflected light from the element.

In other words, if there is no original under the light-emitting element, the light from the light-emitting element will not pass through the platen glass and enter the light-receiving element, and if there is an original, the light from the light-emitting element will be reflected by the surface of the original, and the reflected light will be enters the light receiving element. Therefore, size detection is performed based on the light receiving states of the plurality of light receiving elements.

[Problems with background technology]

However, since a plurality of light emitting elements and light receiving elements are embedded in the holding plate, the structure becomes complicated and expensive.

[Object of the Invention] It is an object of the present invention to provide an optical reading device with a simple structure that can accurately detect the size of a document without providing a special document size detection sensor.

[Summary of the invention]

In order to achieve the above object, the present invention detects the document size from the read information.

That is, the optical reading device of the present invention is an optical reading device that reads information on a document surface by main scanning in the width direction of the document and sub-scanning in the length direction of the document. A detection circuit that obtains document size information, and a circuit that compares the document size information obtained by the detection circuit with pre-stored reference document size information and determines the size of the read document. It is.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an image processing device equipped with an image reader. This image processing device is configured to read an image of a document P using an image reader 1 and then output the image to a laser printer 4 via a reading processing device 3 .

The image reader 1 includes an image sensor 17, a light source 1
9, a lens 21, an amplifier circuit 23, a shading correction circuit 25, a binarization circuit 27, a detection circuit 28, an interface 29, a control circuit 31, and a drive device 33.

The image sensor 17 is a line image sensor made of, for example, a CCD, and includes a fluorescent lamp, a light emitting diode array,
Original P illuminated by a light source 19 such as a halogen lamp
The reflected light is input through the lens 21 and the image information of one row in the horizontal direction of the document P is read (hereinafter referred to as main scanning).
, outputs an image signal. Further, vertical scanning of the original P (hereinafter referred to as sub-scanning) is performed by moving the original using the drive device 33.

Note that the sub-scanning may be performed by moving the image sensor 17 in the sub-scanning direction.

The amplification circuit 23 amplifies the image signal output from the image sensor 17 and supplies it to the shading correction circuit 25.

The shading correction circuit 25 removes shading (distortion) from the image signal from the amplifier circuit 23 and supplies it to the binarization circuit 27 .

The binarization circuit 27 binarizes the signal after the shape ink correction (for example, sets a white part to a high level and a black part to a low level), and outputs the signal to a detection circuit 28 and an interface 2.
9 to the reading processing device 3.

The detection circuit 28 obtains document size information based on binary signals from main scanning and sub-scanning.

That is, the maximum width of the document P obtained from the main scanning information is taken as the size information in the width direction of the document P,
The presence or absence of document detection is stored for each sub-scan, and the detected amount is used as size information of the document P in the length direction. Note that the circuit configuration will be described later.

The interface 33 sends the binarized image signal to the reading processing device 3 such as a control device or a host computer, and also exchanges control information.

The control circuit 31 includes an image sensor 17, a light source 19, a shading correction circuit 25, a binarization circuit 27, and a detection circuit 28.
, the drive device 33, etc., and performs various processing. In particular, the size of the original 15P is determined by comparing the original size information from the detection circuit 28 with pre-stored reference original size information.

The drive device 33 performs sub-scanning by moving the original table using a motor or the like, or moving the original P using rollers.

The reading processing device 3 stores information read by the image reader 1, and also controls the image reader 1 and supplies information to the laser printer 4.

On the other hand, the laser printer 4 includes a radar control device 5, a semiconductor laser 7, a focusing lens 9, a rotating polygon mirror 11, and a photosensitive drum 15 that reproduces an image by emitting a laser beam through a correction lens 13.

Radar control device 5 forms a modulation signal for driving semiconductor radar 7 based on information from reading processing device 3 .

The semiconductor laser 7 is driven by the output of the laser control device 5 to form a laser beam L.

The laser beam is focused by a focusing lens 9, reflected by a rotating polygon mirror 11 rotating in the A direction, and scanned on a photosensitive drum 15 via a correction lens 13.

The rotating polygon mirror 11 is for moving the laser beam L coming from one direction as a scanning beam, and rotates in the A direction at a constant speed.

The correction lens 13 optically corrects uneven scanning speed of the laser beam L.

The photosensitive drum 15 is scanned in the main scanning direction by a laser beam to form, for example, an electrostatic latent image, and is rotated at a constant speed in the B direction about the rotation axis X to perform scanning in the sub-scanning direction.

The detection circuit 28 includes the circuits shown in FIGS. 2 and 3.

The circuit in Figure 2 uses the maximum width information of the document P obtained from the main scanning information as the size information in the width direction of the document P, and the circuit in Figure 3 detects whether or not the document is detected for each sub-scan. is stored, and the detected amount is used as size information in the length direction of the document P.

First, the circuit shown in FIG. 2 will be explained.

゛This circuit consists of an OR circuit 34, a D flip-flop (de
layered flipflop---hereafter DF/
F) 35, AND circuit 37, NOT circuit 39, OR circuit 40, address generator 41, RAM (r
andom access memory) 43.

The OR circuit 34 receives the binary signal E from the binary circuit 27 and the read signal from the RAM 43 as input. DF/F3
5 inputs the output of the OR circuit 34 to the input terminal, and inputs the clock signal G for each image from the control circuit 31 to the input terminal CP, and the output of the OR circuit 34 is held at the output terminal Q by the clock signal G. While the clock signal G is at low level, the state of the input terminal Q does not change;
When Q transitions to high level, information on the input terminal appears at the output terminal Q.

The AND circuit 37 outputs the clock signal G and the CP of the control circuit 31.
The strobe signal H from U is input. Note that the strobe signal H is at a high level when writing read data, and is at a low level when reading data.

A NOT circuit 39 inverts the output of the AND circuit 37.

The OR circuit 40 receives the output of the AND circuit 37 and the clock signal J from the CPU of the control circuit 31 as input. The lock signal J is at a low level when writing read data, and is a clock pulse when reading data.

The address generator 41 creates an address in the RAM 43 every time it receives a high level signal from the OR circuit 40.

The RAM 43 writes the data supplied to the input terminal DI to the address specified by the address generator 41 via the bus Ao-An every time a low level signal is applied to the write terminal W. Reading is performed when writing is not performed.
This is done automatically and is supplied to the CPU of the control circuit 31 and the OR circuit 34 from the read terminal DO.

Next, the circuit shown in FIG. 3 will be explained.

This circuit is an RS flip-flop (resetset
flip flop...--hereinafter referred to as RS F/F) 45, DF/F 47, AND circuit 49, NOT circuit 51, OR circuit 52) Address generator 53, RA
Equipped with M55.

R8F/F45 inputs the binary signal E to the set terminal S, and inputs the 1-scan start signal K in the main scanning direction to the reset terminal R.
is input, and when the set terminal S becomes a high level, the output terminal Q maintains a high level state, and when the reset terminal R becomes a high level, the output terminal Q becomes a low level.

The DF/F 47 inputs the output signal of the RS F/F 45 to its input terminal, and inputs the scan start signal K to its input terminal CP.

NOT circuit 51 inverts the output of OR circuit 49.

The address generator 53 creates an address in the RAM 55 based on the high level signal from the OR circuit 52.

The RAM 55 writes the data supplied to the input terminal DI to the address specified by the address generator 53 via the bus A o -A n every time a low level signal is given to the write terminal W, and writes the data when not writing. The read data is supplied to the CPU of the control circuit 31 from the read terminal DO.

With the above configuration, this device operates as follows.

First, the image sensor 17 scans and reads an image in one row in the horizontal direction of the original P (main scanning). Next, the drive device 33 drives the document P.
to move vertically (sub-scanning). Then, the horizontal image of the document P is read again. This is repeated to input two-dimensional image information.

The horizontal image signal of the document P read by the image sensor 17 is amplified by the amplifier circuit 23. Then, a shading correction circuit 25 performs shading correction, and a binarization circuit 27 binarizes the signal.

This binarized signal is supplied to the reading processing device 3 via the interface 29 and also to the detection circuit 28.

First, the size information of the document P in the main scanning force direction is obtained by the circuit shown in FIG. The DF/F 35 receives binary signals E and 1 through the OR circuit 34 as shown in (a) and Fb) in FIG.
A clock signal G for each image is applied, and a signal as shown in (C) is output from an output terminal Q.

On the other hand, the AND circuit 37 is given the lock signal G and strobe signal H as shown in (b) and (d), so
It becomes the same as the clock signal G of the AND circuit @37 output beam). This signal is inverted by the knot circuit 39 and <e
)become that way.

The output of the AND circuit 37 and the clock signal J of (f) are input to the OR circuit 40, and a signal similar to Φ) is applied to the address generator 41.

Therefore, the address generator 41 sets an address for each pulse of the input signal.

In the RAM 43, data from the F/F 35 is written to this address each time the signal (e) is supplied to the write terminal W. As a result, the length from the left end to the right end of the document P in one scan is processed as the number of addresses between the address corresponding to the left end and the address corresponding to the right end.

When one scan of writing is completed, read data is supplied from the read terminal DO to the CPU of the control circuit 31 and the OR circuit 34.

The read data supplied to the OR circuit 34 is supplied to the DF/F 35 together with the read data from the next main scan. The operations described above are then performed.

The data written in the RAM 43 in this way is fed back to the OR circuit 34 every time one scan is completed, so that the address corresponding to the left edge of the document P is changed to a smaller address in the RAM 43, and the address corresponding to the right edge is changed to the address corresponding to the right edge. The address is replaced by a larger address, and finally the number of addresses between the minimum address corresponding to the left end and the maximum address corresponding to the right end is processed as the width of the document P.

That is, if the document P on the document table is set diagonally with respect to the reference plane, it will be detected as being larger than the actual width of the document.

The CPU of the control circuit 31 compares the maximum width information of the document P supplied from the RAM 43 with pre-stored main scanning direction information for each size, and determines the size in the main scanning direction.

Note that since there are cases where the length of one side is the same, such as B4 size and B5 size or A3 size and A4 size, the overall size is not specified by the size information in the main scanning direction.

On the other hand, size information of the document P in the sub-scanning direction is obtained by the circuit shown in FIG. For R8F/F45, (a) Φ) in Figure 5
A binary signal E and a scan start signal K as shown in (C) are applied, and a signal as shown in (C) is output from the output terminal Q.

Since the AND circuit 49 is supplied with a scan start signal as shown in (b) (ψ) and a strobe signal H, the output of the AND circuit 49 is similar to the scan start signal of 0)). The output of the knot circuit 51 is inverted and becomes as shown in (e).

The output of the AND circuit 49 and the clock signal J of (f>) are input to the OR circuit 52, and the same signal as in (b) is applied to the address generator 53.

Therefore, the address generator 53 sets an address for each pulse of the input signal.

In RAM55 (to the write terminal W to the other address (e)
Data from the DF/F 47 is written every time the signal is supplied.

When the writing is completed, the data is sent to the CPU of the control circuit 31.

The information sent to the CPU of the control circuit 31 is compared with pre-stored information in the sub-scanning direction for each size, and the size in the sub-scanning direction is determined.

Therefore, a specific document size is determined together with the previous size determination in the main scanning direction.

As a result, for example, the size of the copy paper can be determined by the reading processing device 3.
The laser printer 4 is instructed to transfer the electrostatic latent image formed on the photosensitive drum 15 onto the paper.

As described above, according to this embodiment, size information in the width direction of the document P is obtained from the main scanning information by the circuit shown in FIG.
The circuit shown in the figure obtains size information in the length direction of the document P from the sub-scanning information, and the CPU of the control circuit 31 compares both size information with pre-stored standard document size information,
Since the size of the read document P is determined, the document size can be detected by processing the image signal without the need to newly provide a sensor for detecting the document size.

Therefore, it is not necessary to provide a large number of sensors for detecting the document size on the document holding plate, etc., and the structure is simplified and reliable size detection can be performed.

In addition, the prefectural paper P obtained from the main scanning information by the circuit shown in Figure 2
Since the largest width information is used as the size information in the width direction of the document P, if the document P is set crooked beyond the allowable range, this size information can be used to re-set the document, etc. can be displayed or a warning can be issued.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

For example, in the embodiment described above, size detection is performed in the main scanning direction and the sub-scanning direction, but if the size of the target document does not have the same size in vertical length and length, it is necessary to detect the size in the main scanning direction. Alternatively, the document size can also be determined by detecting the size in either of the sub-scanning directions.

Note that if size detection can be performed only in the main scanning direction, size detection can also be performed in the first scan. Therefore, size detection can be performed easily and extremely quickly.

〔Effect of the invention〕

As explained above, according to the present invention, document size information is obtained from at least one of main scanning information and sub-scanning information, and this document size information is compared with pre-stored reference document size information, and the read document is Since the size is determined, it is possible to obtain an optical reading device with a simple structure that can accurately detect the size of a document without providing a special document size detection sensor.

[Brief explanation of drawings]

1 to 5 are diagrams for explaining one embodiment of the present invention, in which FIG. 1 shows a schematic configuration of an image processing device equipped with an image reader, and FIG. 2 shows information in the main scanning direction. FIG. 3 is a circuit diagram for performing information processing in the sub-scanning direction, FIG. 4 is an explanatory diagram of the operation of FIG. 2, and FIG. 5 is an explanatory diagram of the operation of FIG. 3.

Claims (4)

[Claims] (1) In an optical reading device that reads information on a document surface by main scanning in the document width direction and sub-scanning in the document length direction, a detection circuit obtains document size information from at least one of main scanning information and sub-scanning information. and a circuit that compares the document size information obtained by the detection circuit with reference document size information stored in advance and determines the size of the document to be read. (2) In the optical reading device according to claim 1, the detection circuit obtains size information in the width direction of the document from the main scanning information, and obtains size information in the length direction of the document from the sub-scanning information. An optical reading device characterized in that: (3) In the optical reading device according to claim 1, the detection circuit uses the maximum width information of the document obtained from the main scanning information as the size information in the width direction of the document. An optical reading device characterized by: (4) In the optical reading device according to claim 1, the detection circuit stores whether or not a document is detected for each sub-scan, and uses the detected amount as size information in the length direction of the document. An optical reading device characterized by: