JPH10107966A - Detector for deviated offset for image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the simple technology that detects a deviated offset of a read position of an optical unit due to impact or thermal deformation or the like with respect to the image reader. SOLUTION: The reader is provided with a setting device that sets a position in the main scanning direction from a reference position or a reference mark width (a) of a mark 23 which is a V shaped, wedge shaped or slant line shaped mark in the subscanning direction placed at a read position of an image sensor 11, and a deviation (x) in the subscanning direction is calculated, based on a detection width (b) of the mark 23 detected by the linear image sensor 11, or the reference mark width (a) set to the setting device and the detected position, a difference from the reference position and a tilt angle θ of a side of the mark 23. The two marks are spaced apart in the main scanning direction so as to attain a structure without the provision of the setting device or a structure to detect a skew. Moreover, the width of the mark and the position are both detected to detect an offset deviation in both the main and subscanning directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading information displayed on a document surface as an image, and a reading area set by an impact applied to the apparatus or thermal deformation of the apparatus. The present invention relates to an apparatus for correcting the occurrence of an offset shift in (image cutout position).

[0002]

2. Description of the Related Art An image reading device having a normal structure used as an input device of an electronic computer uses a one-dimensional image sensor as a photoelectric conversion element. Relative movement between the optical unit and the optical unit on which the image sensor is mounted. Flatbed-type ones that run an optical unit have the characteristic that they can read bound originals such as books. It is suitable for continuously reading the sheet document of the.

FIG. 13 schematically shows the structure of an image reading apparatus having a flatbed type reading section A and an automatic sheet feeding type reading section B. It is an example of a device provided with a part B. The flatbed reading unit A includes a document table 1 made of a transparent plate, a document holder 2 covered on the document table 1, and a moving optical unit 3 running along the lower surface of the document table 1. On the other hand, automatic paper feed reading section B
Is a document feeder including a paper feed table 4, a paper feed roller 5 provided with a document separating means (not shown) and two pairs of feed rollers 6, 7, a stacker 8 of read documents, And a fixed optical unit 9 fixed to the camera. Each of the optical units 3 and 9 includes a one-dimensional image sensor 11, an imaging lens 12, and a reflection mirror 13 in the case of a reduction optical system. The main scanning direction of the one-dimensional image sensor 11 is a direction perpendicular to the plane of the drawing.

When an original is read by the flatbed reading section A of the image reading apparatus shown in FIG.
Then, the movable optical unit 3 is read by moving the movable optical unit 3 in the horizontal direction (sub-scanning direction) in the figure. When the original is read by the automatic paper feed reading unit B, the original is mounted on the paper feed table 4 and the rollers 5, 6, 7 feed the original one sheet at a time from the right side to the left side in the sub-scanning direction. read. During the automatic paper feed reading, the movable optical unit 3 is stopped at a position substantially opposed to the fixed optical unit 9 and the original is read by both the fixed and movable optical units, whereby both sides of the original can be read.

In the above-described image reading apparatus, the optical units 3 and 9 are affected by the impact, temperature change, and the like received by the apparatus.
May be offset by about 1 mm in the sub-scanning direction. This offset shift is caused by a slight change in the angle of the reflection mirror 13 in the optical units 3 and 9 and the relative positional relationship between the optical units 3 and 9 and the reading positions 14 and 15 of the original table 1 and the automatic paper feed reading unit. Is caused by a slight madness.

As shown in FIG. 14, the offset deviation of the flatbed reading section A is caused by a start mark (first start mark) to be read on the original table 1 by the moving optical unit 3.
The displacement of the movable optical unit 3 when the start mark 16 is read is detected by the number of pulses of the pulse motor for moving the movable optical unit 3, and the image cutout position 17 is determined by the detected number of pulses. By performing the correction, the offset deviation can be corrected. Since the platen 1 is generally provided with a white reference 18 and a black reference 19 for correcting the sensitivity of the image sensor 11, the boundary between the two 18 and 19 should be used as the start mark 16. Can be.

[0007]

In the movable optical unit 3, the offset deviation can be detected by providing a reference mark such as the above-mentioned start mark 16 at a position deviating from the reading area of the document, and therefore, the correction thereof can be performed. Easy. However, since the fixed optical unit 9 cannot move in the sub-scanning direction, the offset deviation cannot be detected by the above-described method, and therefore cannot be corrected.

It is a first object of the present invention to provide a simple technical means for detecting an offset deviation in the sub-scanning direction of a fixed optical unit having a fixed position in the sub-scanning direction. Along with the offset deviation,
The second is to obtain a technical means capable of detecting an offset deviation in the main scanning direction and an inclination (skew) of a reading line.
The challenge.

[0009]

According to a first aspect of the present invention, there is provided an offset deviation detecting apparatus, wherein a fixed optical unit provided in a fixed position in a sub-scanning direction facing a paper path and a main scanning in a sensor array array direction. In the image reading apparatus provided with the one-dimensional image sensor 11 mounted on the fixed optical unit 9 in the direction, the mark having the V-shaped or wedge-shaped side in the sub-scanning direction provided at the reading position of the one-dimensional image sensor 11 23, a mark width setting device 24 for setting a reference mark width a of the mark, and a difference between the detection width b of the mark 23 detected by the one-dimensional image sensor 11 and the reference mark width a set in the setting device 24. And a calculating means 26 for calculating a deviation x in the sub-scanning direction based on the inclination angle θ of the side of the mark 23.

The offset displacement detecting device according to the second aspect of the present invention provides a mark 23L having a V-shaped or wedge-shaped side in the sub-scanning direction.
23R are provided opposite to each other at intervals in the main scanning direction of the one-dimensional image sensor 11, and include two marks 23L, 2L detected by the one-dimensional image sensor 11.
The difference between the detection widths b ₁ and b _{2 of the} 3R and the marks 23L, 2L
And a calculating means 26 for calculating a deviation x in the sub-scanning direction based on the angle θ of the side of 3R.

According to a third aspect of the present invention, there is provided an offset deviation detecting apparatus, comprising: the mark according to the first aspect;
A skew detection mark 23P having a V-shaped or wedge-shaped side in the sub-scanning direction in the same direction as the mark is provided at a distance from one of the 3Rs in the main scanning direction.

According to a fourth aspect of the present invention, there is provided the offset deviation detecting device according to the first or second aspect.
L, 23R, a mark position setting device 24 for setting a position in the main scanning direction, and a position of the mark in the main scanning direction based on a position detected by the image sensor 11 and a set value of the mark position setting device. Calculation means 2 for calculating bias y
6 is provided.

According to a fifth aspect of the present invention, there is provided an offset displacement detecting device in which an inclined linear mark is provided in place of the mark having a V-shaped or wedge-shaped side, and a mark in a main scanning direction is provided.
A mark position setting device 24 for setting the reference position 29 of the first
Linear mark 31 detected by one-dimensional image sensor 11
And a calculating means 26 for calculating the deviation x in the sub-scanning direction based on the detected position b of the above-mentioned and the set value a set in the setter 24.

According to a sixth aspect of the present invention, there is provided a transparent document table for guiding a surface of a document fed in a sub-scanning direction.
A fixed optical unit 9 having a fixed position in the sub-scanning direction and a movable optical unit 3 traveling in the sub-scanning direction are disposed with the sensor array in each of the fixed and movable optical units 9 and 3 in the main scanning direction. The first start mark 1 is mounted on the transparent platen 1 by the moving optical unit 3.
6 is adopted in the image reading apparatus provided with
A second start mark 32 provided on the movable optical unit 3 toward the fixed optical unit 9, a first setting unit 43 for setting a reference position of the first start mark 16, and a reading position of the movable optical unit 3. A second setting device 44 for setting a reference position of the second start mark 32; a position information of the movable optical unit 3 when the movable optical unit reads the first start mark 16; Calculation means 26 for calculating a deviation x in the sub-scanning direction of the reading position of the fixed optical unit 9 based on the position information of the movable optical unit 3 when the start mark is read and the set values of the first and second setting devices. It is provided with.

[0015]

1 to 3 show a first embodiment of the present invention.
It shows an example. In the automatic paper feed reading section B, a paper path 20 is formed by feed roller pairs 6 and 7 arranged in parallel.
The document 21 separated and fed one by one passes through the paper path 20, and the information written on the upper surface thereof is read by the fixed optical unit 9. Read line 14 of fixed optical unit 9
Is a direction (main scanning direction) perpendicular to the feeding direction S (sub-scanning direction) and is set at an intermediate position between the feed roller pairs 6 and 7. The front side of the paper path 20 (feeding direction S
On the frame, a mount 22 provided with an isosceles triangular mark 23 is attached. The center line of the mark 23 (the line bisecting the apex angle) is parallel to the sub-scanning direction, and the base angle of the mark 23 is θ. In the control unit of the image reading apparatus, the width a of the mark read by the fixed optical unit 9 at the time of initial setting of the apparatus is initially registered in the mark setting unit 24, and at the same time, the inclination angle θ of the oblique side of the mark 23 is also registered.

When an impact is applied to the image reading apparatus having such a structure or when the temperature changes, an offset shift of the fixed optical unit may occur. A reading position 14a indicated by an imaginary line in FIGS. 1 and 2 indicates a reading position when an offset shift occurs in the sub-scanning direction, and the width of the mark 23 read by the one-dimensional image sensor 11 is changed from a to b. Has changed.

Then, the width b of the mark after the offset shift is detected by the detector 25, the detected value b is compared with the initial set value a, and the shift amount x of the read line 14 in the sub-scanning direction is calculated by the calculating means 26. I do. An arithmetic expression when an isosceles triangle with a base angle θ is used as the mark 23 is x = ((ab) / 2) ·
tan θ.

The mark used for such detection may be any mark provided that it has a side inclined at a predetermined angle. In addition to the isosceles triangle, a V-shaped line mark 23a as shown in FIG. 3A, a wedge-shaped triangle (right-angled triangle) mark 23b as shown in FIG. 3B, a wedge-shaped line mark 23c as shown in FIG. Can be exemplified.

By providing two such marks at an interval in the main scanning direction with the apical direction being the same direction,
The inclination (skew) of the reading line 14 can be detected. FIG. 4 shows the principle, in which the reading line 14
FIG. 9 is an explanatory diagram when skew is performed at a position c. Assuming that the skew angle is α and the distance between marks is T, it can be obtained as tan α = (x ₁ −x ₂ ) / T from the deviations x ₁ and x ₂ in the sub-scanning direction calculated for the marks on both sides.

FIGS. 5 and 6 show a third embodiment of the present invention. In this example, isosceles triangular marks are provided on both sides of the paper path, with one 23L facing downstream and the other 23R facing upstream. When the reading line 14 becomes 14a due to an impact or the like on the image reading device, the deviation x in the sub-scanning direction can be obtained by the same formula and device as in the first embodiment, and the detection width of the marks 23L and 23R can be obtained. if b ₁ and b ₂ are Oke was initially set to be equal, it is also possible to detect the sub-scanning direction offset from the difference between b ₁ and b ₂ when the detected. That is, detected by the detector 27 the width b ₁ of the marks 23L detects the width b ₂ of the mark 23R in the detector _{28, x = ((b 1} -b 2) / 4) · t
The calculation means 26 calculates anθ (when the mark is an isosceles triangle with the base angle θ) to obtain a deviation x in the sub-scanning direction.

By combining the embodiments shown in FIGS. 5 and 6 with the embodiment shown in FIG. 4, the configuration shown in FIG. 7 in which the deviation and the skew in the sub-scanning direction are detected with three marks can be obtained. In this example, a mark 23P having the same shape as that of the mark 23R is provided further outside the right mark 23R.

FIG. 8 shows a fifth embodiment of the present invention. The deviation y in the main scanning direction and the deviation x in the sub-scanning direction of the mark 23 with respect to the reference position 29 of the one-dimensional image sensor can be detected. It was done. That is, the distance from the reference position 29 to the center of the mark is Q, the width of the mark at the reading position 14 is a, the distance from the reference position 29 after the offset shift to the center of the mark 23 is R, and the reading position after the offset shift. Assuming that the width of the mark at 14a is b, the deviation y in the main scanning direction can be obtained by RQ, and the deviation x in the sub-scanning direction can be obtained by ((ba) / 2) tan θ.

FIG. 9 shows a sixth embodiment of the present invention. In the present embodiment, an inclined line 31 is used as the mark 23. The inclination line 31 intersects the reading line 14 at an inclination angle θ. If the reading line 14 moves by the distance x in the sub-scanning direction due to an impact or the like, the distance a from the reference position 29 of the one-dimensional image sensor before the offset shift changes to the distance b. Therefore, the displacement x in the sub-scanning direction is (b−
a) It can be obtained by tan θ.

FIG. 10 shows a seventh embodiment of the present invention. In the double-sided image reading apparatus, the offset deviation of the fixed optical unit 9 can be corrected by attaching the second start mark 32 to the movable optical unit 3. First, a moving amount 1 when the moving optical unit 3 is moved to a position where a first start mark 16 (a boundary between a black reference and a white reference) provided on the lower surface of the document table 1 is read is detected. The difference Δl from the reference value set in 43 is calculated. Next, this position is moved to the fixed optical unit side as the reference position 33, and the movement amount m when the fixed optical unit 9 moves to the position where the second start mark 32 (the boundary between the black reference and the white reference) is read is detected. And the second setting device 4
The difference Δm from the reference value set to 4 is calculated. The offset shift x of the reading line 14 of the fixed optical unit 9 is x = Δ
It can be calculated by 1 + Δm.

In an image reading apparatus of a reduced optical system having a structure in which an optical path is folded by a reflection mirror, an offset deviation of the optical units 3 and 9 in the sub-scanning direction often occurs due to a slight deviation of the angle of the reflection mirror. FIG. 11 and FIG. 12 show a support structure of a reflection mirror which is effective for preventing an angle shift.

In the conventional structure shown in FIG. 12, the reflecting mirror 13 is supported by an L-shaped block 34 on the side surface. The block 34 is a resin molded product, and includes a seat 35 that supports the lower end surface of the reflection mirror 13 and a backrest 36 that supports the rear surface of the reflection mirror. The backrest portion 36 has upper and lower support projections 37 and 38 at the center of the front surface, and has a clip locking projection 39 on the back surface. At the connecting portion between the support projection 38 below the block and the upper surface of the seat portion, it is impossible to avoid the occurrence of the upper radius 45 of the resin molding (see FIG. 12A). Therefore, the clip 41 locked to the locking projection 39
When the reflection mirror 13 is urged toward the front side of the backrest 36, the lower edge of the reflection mirror 13 moves up and down along the radius 45, and the angle of the reflection mirror is not stable.

In the conventional structure shown in FIG. 12, if the lower end surface of the reflecting mirror is inclined, an error occurs in the angle of the reflecting surface due to the contact with the seat 35 of the block (see FIG. 12B).

Therefore, as shown in FIG. 11, a projection 42 higher than the radius 45 is formed on the upper surface of the seat 35 of the block 34.
By supporting the lower end surface of the reflection mirror 13 with the projection, it is possible to prevent the angle deviation of the reflection mirror due to the above-described cause, and to prevent the offset deviation in the sub-scanning direction.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment.

FIG. 2 is a block diagram of a first embodiment.

FIG. 3 is a schematic view showing another example of a mark.

FIG. 4 is a schematic view of a second embodiment.

FIG. 5 is a perspective view of a third embodiment.

FIG. 6 is a block diagram of a third embodiment.

FIG. 7 is a schematic diagram of a fourth embodiment.

FIG. 8 is a schematic view of a fifth embodiment.

FIG. 9 is a schematic view of a sixth embodiment.

FIG. 10 is a schematic view of a seventh embodiment.

FIG. 11 is a diagram showing a support structure of a reflection mirror;

FIG. 12 is a side view showing a conventional support structure of a reflection mirror;

FIG. 13 is a side view of a conventional image reading apparatus.

FIG. 14 is a schematic view showing an offset shift.

[Explanation of symbols]

 Reference Signs List 1 platen 3 moving optical unit 9 fixed optical unit 11 one-dimensional image sensor 16 start mark 20 paper path 23 mark 24 mark width setting device 25 detector 26 calculation means 29 reference position 31 inclined line 32 second start mark 43 first setting Unit 44 second setting unit a reference mark width b mark detection width x deviation in the sub-scanning direction θ inclination angle

Claims (6)

[Claims] 1. A fixed optical unit (9) provided facing a paper path (20) and fixed at a position in a sub-scanning direction, and a fixed optical unit (9) having a sensor array arranged in a main scanning direction.
An image reading apparatus provided with a one-dimensional image sensor (11) mounted on a mark (23) provided at a reading position of the one-dimensional image sensor (11) and having a V-shaped or wedge-shaped side in the sub-scanning direction. And a mark width setting device (24) for setting a reference mark width (a) of the mark, and a one-dimensional image sensor (11)
Based on the difference between the detection width (b) of the mark (23) detected in step (b) and the reference mark width (a) set in the setting device (24), and the inclination angle (θ) of the side of the mark (23). An offset deviation detecting device comprising: a calculating means (26) for calculating a deviation (x) in the scanning direction. 2. A fixed optical unit (9) having a fixed position in the sub-scanning direction facing the paper path (20), and a fixed optical unit (9) having the sensor array arranged in the main scanning direction.
An image reading apparatus provided with a one-dimensional image sensor (11) mounted on a sub-scanning direction provided at a reading position of the one-dimensional image sensor (11) in a direction opposite to the main scanning direction. With V-shaped or wedge-shaped sides
(23L, 23R) and the two marks which are detected by the one-dimensional image sensor (11) (23L, 23R) detects a width of (b _1, b ₂₎ mutual differences and the mark (23L, 23R) sides of the A calculating means (26) for calculating a deviation (x) in the sub-scanning direction based on the angle (θ). 3. A V-shape in the sub-scanning direction in the same direction as the mark, separated from the mark (23) or the mark (23L, 23R) in claim 1 by a distance in the main scanning direction. 3. The offset deviation detecting device according to claim 1, further comprising a skew detection mark having a wedge-shaped side. 4. A mark position setting device (24) for setting a position in the main scanning direction of one of the mark (23) and the mark (23L, 23R) of claim 2, and a side of the mark. 4. A calculating means (26) for calculating a deviation (y) in the main scanning direction based on a position detected by the image sensor (11) and a set value of the mark position setting device. An offset displacement detection device as described in the above. 5. A fixed optical unit (9) provided in a fixed position in the sub-scanning direction facing the paper path (20), and a fixed optical unit with the sensor array arranged in the main scanning direction.
(9) In the image reading device provided with the one-dimensional image sensor (11) mounted on the (9), an inclined linear mark (31) provided at the reading position of the one-dimensional image sensor (11), the main scanning A mark position setting device (24) for setting the reference position (29) of the direction mark (31), and a detection position (b) and a setting device for the linear mark (31) detected by the one-dimensional image sensor (11). An offset deviation detecting device, comprising: calculating means (26) for calculating a deviation (x) in the sub-scanning direction based on the set value (a) set in (24). 6. A fixed optical unit (9) having a fixed position in the sub-scanning direction across a transparent platen (1) for guiding the surface of a document fed in the sub-scanning direction, and a movement traveling in the sub-scanning direction. An optical unit (3) is arranged, and each of the fixed and movable optical units (9, 3) is equipped with a one-dimensional image sensor (11, 11) in which the direction of the sensor array is in the main scanning direction. In an image reading apparatus in which a first start mark (16) to be read by a movable optical unit (3) is provided on a table (1), a movable optical unit (3) is provided facing a fixed optical unit (9). The second start mark (32)
A first setting device (43) for setting a reference position of the first start mark (16); and a second setting device for setting a reference position of the second start mark (32) with respect to the reading position of the movable optical unit (3). The position information of the movable optical unit (3) when the movable optical unit reads the first start mark (16) and the position information of the movable optical unit (3) when the fixed optical unit reads the second start mark A calculating means (26) for calculating a deviation (x) in the sub-scanning direction of the reading position of the fixed optical unit (9) based on the position information of the movable optical unit (3) and the set values of the first and second setting devices. ).