JPH04111670A - Picture reader - Google Patents

Abstract

PURPOSE:To decide a read origin in the main and sub scanning directions by providing a reference mark deciding a read original in the main scanning direction with a line sensor and a reference mark deciding a read original in the sub scanning direction to the end in the sub scanning direction. CONSTITUTION:A picture signal on a line (2) is sequentially written in a line memory 30 by setting a white level to 1 and a black level to 0, for example. Thus, when a control circuit 33 reads a picture data in the order of the signal written in the line memory 30, a position at which the level changes from 0 to 1, that is, an origin X0 is obtained. Based on a step number by a motor 36, the distance between lines (1) and (2) and a distance Y1 between lines (2) and (3) are obtained. Furthermore, a distance YL between the origin Y0 and the line (3) is decided in advance at the manufacture of a reference sheet 20, then a distance YH between the origin Y0 and the line (1) is obtained by YL-Y1. Thus, in the case of reading an original, the scanner 21 is moved toward Y by the distance YH from the home position (1) and the read is started, then the read is started from the origin Y0.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device that reads an image of a document using a line sensor, and more particularly to a reading device that automatically determines a reading origin.

[Conventional technology]

FIG. 2 is a partially cutaway perspective view of a conventional image reading device.

As shown in the figure, the conventional device includes a casing 2 having a transparent glass 1 on the top surface, and a glass 1 provided below the glass 1 so as to be movable along guide shafts 3 and 4.
A scanner 5 that reads an image of an upper original (not shown); and a belt 11 that is wound around pulleys 6 and 7 and that moves the scanner 5 by the driving force of a motor 10 that is transmitted via gears 8 and 9. is provided. Here, the scanner 5 includes a fluorescent lamp 5a that irradiates light onto the original, a window 5b, a mirror and a lens (not shown), and a COD sensor (not shown) supported by a substrate 5c. ing. In addition, in the figure, XW is the width of crow 1 (X direction), and Yw is
indicates the length of the glass 1 (in the Y direction). Further, the home position of the scanner 5 is set by the home sensor 13 detecting the detection lever 12. Further, the original image on the glass 1 is read by a scanner 5 that moves in the Y direction from the home position.

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional apparatus, when determining the reading origin θ (Xo, Yo> in the main scanning direction and the sub-scanning direction), the operator or the mounting position of the component must be adjusted.
This adjustment is very subtle and takes time.
In addition, there was a problem in that accuracy was large due to adjustment errors due to individual differences among workers.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art described above, and an object of the present invention is to provide an image reading apparatus that can automatically set a reading origin.

[Means for Solving 5 Problems] The image reading device according to the present invention includes a line sensor including a plurality of light receiving elements arranged in the main scanning direction, and a sub-line sensor orthogonal to the main scanning direction. a reference mark in the main scanning direction, which is provided at an end in the sub-scanning direction and for determining a reading origin in the main scanning direction by the line sensor; A reference mark in the sub-scanning direction is provided at the end of the direction and is used to determine the reading origin in the sub-scanning direction by the line sensor, and a main scanning direction is performed based on the reading result of the reference mark in the main-scanning direction by the line sensor. and control means for determining the reading origin in the sub-scanning direction based on the position when the line sensor moved by the moving means reads the reference mark in the sub-scanning direction. Consisted of.

[For production]

In the present invention, a reference mark in the main scanning direction for determining the reading origin in the main scanning direction by the line sensor and a line sensor are provided at the end in the sub scanning direction, for example, by using a sheet with a black part formed on a white background. and a reference mark in the sub-scanning direction for determining the reading origin in the sub-scanning direction.

Therefore, if the line sensor reads the reference mark in the main scanning direction, the reading origin in the main scanning direction can be determined based on this result, and the line sensor moved by the moving means can also read the reference mark in the sub-scanning direction. The reading origin in the sub-scanning direction can be determined based on the position when the image is read.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

FIG. 1 is a block diagram showing an embodiment of an image reading device according to the present invention.

The apparatus of this embodiment has a casing equipped with a transparent glass serving as a document table, similar to the conventional example shown in FIG. As shown in FIG. 1, a black reference mark 20b is placed on a white background (white part) 20a on the top or bottom surface of the edge of the transparent glass.
and 20c are attached. Here, the reference mark 20b is a reference mark in the main scanning direction, and the end (
In the figure, the upper end of the reference mark 20b extending in the Y direction)
The reference mark 20c is a reference mark in the sub-scanning direction, and the edge of the reference mark 20c that is the boundary with the white background 20a (in the figure , the left end of the reference mark 20c extending in the X direction) is set at a position separated by a distance of ¥ from the reading origin θ (Xo, Yo) in the sub-scanning direction.

Further, in this embodiment, a CC formed by arranging a plurality of CCDs is used.
It is equipped with a scanner 21 equipped with a D sensor 21a, and a lens 22 that focuses an original image on the CCD sensor 21a.

Furthermore, this embodiment includes a binarization processing section 23 for binarizing the output signal of the scanner 21. The binarization processing unit 23 includes an amplifier 24 that amplifies the output C of the scanner 21 to a certain level, a normalization circuit 25 that corrects shading for uneven illumination of the light source and peripheral light intensity deterioration characteristics due to the lens, and a A 2fM converter that binarizes the image signal output from the white reference memory 26 and the normalization circuit 25 based on a predetermined threshold level. It consists of a circuit 27.

In addition, in this embodiment, a memory section 28 having a memory selector 29 and a line memory 30, a timing generator 31 consisting of a programmable counter, etc., a signal drawing section 32 consisting of an AND gate, and a host computer 50 are included in the reading device. I'/F selector 3 for connection
4, an interface (I/F) 35, and a control circuit 33 that controls the entire circuit and is composed of a microprocessor and the like.

36 is a stepping motor for moving the scanner 21 in the sub-scanning direction, 37 is a motor drive circuit for driving the motor 36, 38 is a sensor for detecting the home position of the scanner 21 in the sub-scanning direction, and 39 is a sensor for the sensor 38. A sensor receiver that receives a detection signal.

Here, the timing generator 31 is connected to the scanner 2.
1, a shift pulse S and a control clock CL in the main scanning direction are outputted, and a control clock CL in the main scanning direction and a gate control signal G are outputted to the AND gate of the signal extraction section 32. In addition, the control clock CL is a regular north time #! for synchronous control. 25, a white reference memory 26, and a binarization circuit 27.

Incidentally, FIG. 3 is a timing chart for explaining the operation of this embodiment, and the above-mentioned signal waveforms are shown in the same figure.

Further, the line memory 30 has an address counter that stores a binary image signal in synchronization with the output signal E from the signal rendering section 32, and the two memory selectors are configured to operate in binary format according to a command from the control circuit 33. It is selected whether the image signal from the conversion circuit 27 is to be written into the line memory 30 or the contents of the line memory 30 are to be read by the control circuit 33.

Furthermore, the control circuit 33 includes a timing generator 3
1, while sending a setting signal for setting the output timing of the gate control signal G to the white reference memory 26, and also directing the image data in the line memory 30 to the host computer 50 via the interface 35. Line memory 30 and I/F selector 34 for output
control.

The operation of this embodiment having the above configuration will be explained below based on FIGS. 1 and 3.

First, in this embodiment, the motor 36 is driven via the motor drive section 37 to move the scanner 21, and when the home sensor 38 detects a detection lever (not shown) provided on the scanner 21, the sensor receiver 39 is moved. The detection signal is transmitted to the control circuit 33 via. The control circuit 33 receives the detection signal, stops the motor 36, and sets this position as the home position. At this home position, the scanner 21 reads the white portion 20a on the reference sheet 20 on line 2.

This image signal is stored in the white reference memory 26 according to a command from the control circuit 33.

Next, the scanner 21 is moved a predetermined distance in the opposite direction to the sub-scanning direction (Y direction) so as to be above the line (2), and the image on the line (2) is read at this position. After a time To from the shift pulse S, the scanner 21 reads an image in synchronization with the control tarlock CL in the main scanning direction, and serially inputs the image signal to the binarization processing section 23. Binarization processing unit 23
outputs a binarized image signal.

The control circuit R33 outputs to the timing generator 31 in advance a gate control signal G that sets a width corresponding to the output width T of the CCD sensor 21b to a high level. Based on the output of the timing generator 31, the AND gate of the signal rendering section 32 outputs the control clock CL in the main scanning direction to the line memory 3o only while the gate control signal G is at a high level.

The control circuit 33 controls the memory selector 29 to send the image signal on the line ■ of the reference sheet 2o from the binarization processing section 23 to the line memory 3o, and synchronizes it with the timing of the output signal E from the signal drawing section 32. Then, the image signal on line ■ is written into the line memory 30. Next, the control circuit 33 controls the memory selector 29 to determine the origin Xo based on the image signal on the line (2) written in the line memory 30.

The image signals on line (2) are sequentially written into the line memory 30 with the white level set to 111N and the black level set to "O", for example. Therefore, if the control circuit 33 reads out the image data in the order written in the line memory 30, the level will be "0".
to "1", that is, the origin Xo/i2 position shown in FIGS. 1 and 3 (reference mark 2 in the main scanning direction)
The position of the boundary between Qb and the white portion 20a) can be found.

Next, the scanner 21 is moved in the opposite direction to the Y direction by the motor 36, and the scanner 21 is stopped when all the image data reaches the black level "O".

Since the moving distance for one step of the stepping motor is predetermined, the distance Y1, which is the sum of the distance from line 2 to 2 and the distance from line 2 to 2, can be determined based on the number of steps. Also, the origin Y.

The distance Y from to the line ■ is the reference sheet 20! ! !
Since it is predetermined at the time of printing, the distance between the origin Y and the line ()'1 can be found from (Y, -Yl).

Therefore, when reading a document, if the scanner 21 is moved from the home position (3) in the Y direction by a distance VaYH, then the reading starts at the origin Y. Karame reading starts.

As described above, according to this embodiment, the reading origin in the main scanning direction can be determined based on the reading result of the reference mark in the main scanning direction, and the stepping motor 36
The reading origin in the sub-scanning direction can be determined based on the position when the moving scanner 21 reads the reference mark 20c in the sub-scanning direction.

〔Effect of the invention〕

As described above, according to the present invention, the reading origin in the main scanning direction can be determined based on the reading result of the reference mark in the main scanning direction, and the line sensor moved by the moving means can be moved in the sub scanning direction. The reading origin in the sub-scanning direction can be determined based on the position when the reference mark is read. Therefore, the reading origin can be set automatically and very accurately without relying on an adjustment operator.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an image reading device according to the present invention, FIG. 2 is a partially cutaway perspective view of a conventional image reading device, and FIG. 3 shows the operation of this embodiment. FIG. 20...Sheet 20b...Reference mark 20c in the main scanning direction...Reference mark 21 in the sub-scanning direction...Scanner 21a...CCD sensor 23...Binarization processing section 24...Amplifier 25... Normalization circuit 26... White reference memory 27... Binarization circuit 28... Memory section 9... Memory selector 0... Line memory ■... Timing generator 2... Signal drawing section 3...control circuit

Claims (1)

[Scope of Claims] An image reading device comprising: a line sensor including a plurality of light receiving elements arranged in a main scanning direction; and a moving means for moving the line sensor in a sub-scanning direction perpendicular to the main scanning direction. , a reference mark in the main scanning direction, provided at the end in the sub-scanning direction, for determining the reading origin in the main scanning direction by the line sensor; and a reference mark in the main scanning direction, provided at the end in the sub-scanning direction, for determining the reading origin in the main scanning direction by the line sensor. A reference mark in the sub-scanning direction for determining a reading origin in the direction, and a reading origin in the main scanning direction based on the reading result of the reference mark in the main scanning direction by the line sensor, and the reading origin is moved by the moving means. An image reading device comprising: control means for determining a reading origin in the sub-scanning direction based on a position when the line sensor reads the reference mark in the sub-scanning direction.