JPH08274951A - Image reader - Google Patents

Abstract

PURPOSE: To provide an original reader correcting an image based on the sensing of a tilt in a read optical axis and a tilt of an original scale based on read data from an image pickup sensor. CONSTITUTION: The original reader is provided with a 1st carriage exposing an original placed on a contact glass and obtaining a reflected optical image from the original, a 2nd carriage leading the reflected optical image from the 1st carriage to an optical lens, and an image pickup sensor 22 applying photoelectric conversion to the image formed by the optical lens. The original reader conducts reading under the control of a scanner control section 101. The original reader 11 is provided with a distortion detection means including a distortion calculation means 121 using the image pickup sensor 22 to read a display body provided in a prescribed area and detecting the distortion of the image based on the read data and with an image correction means using a sensor rotation mechanism 123 to rotate a CCD sensor 22 around the lens optical axis based on the image distortion data detected by the distortion detection means so as to correct image distortion.

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 used in a copying machine or the like, and more particularly to reading an image of a document placed on a contact glass with an image sensor and forming an image read from the image sensor. The present invention relates to an image reading apparatus that corrects distortion when it is present.

[0002]

2. Description of the Related Art As is well known, an image reading apparatus of this kind is used in, for example, a digital copying machine. The basic configuration of the digital copying machine is the image reading device,
Generally, a printer unit having a laser beam scanning device and an automatic document feeder are provided. Here, the automatic document feeder is a device that conveys the set originals one by one, sets them on the contact glass, and discharges the originals on the contact glass after copying is completed. Further, the image reading apparatus includes a first carriage equipped with a light source including an illumination lamp and a reflecting mirror and a first mirror, a second carriage equipped with a second mirror and a third mirror, and via each mirror of these carriages. It is provided with an optical lens for forming an optical image sent thereto and an image sensor such as a CCD sensor for converting the optical image formed by the optical lens into an image signal.

Further, in the above-mentioned printer section, during the copying operation, after the photosensitive drum is uniformly charged by the charging device by being rotationally driven by the driving section, image exposure by the digital image signal subjected to the image processing is performed by the laser. An electrostatic image is formed by the beam scanning device, and the electrostatic image on the photoconductor drum is transferred and developed on a sheet by the developing device 28.

The operation of such a digital copying machine will be described with reference to FIG. FIG. 38 is a view of the contact glass 501 seen from above, and is also an explanatory view showing the read timing MSG in the main scanning direction M and the read tamming SSG in the sub scanning direction S together. Note that the symbol LSYNC of the timing MSG is a synchronizing signal, and the symbol LGATE is a document reading range defining gate signal. Further, the code SLEAD of the timing SSG
Is a shading gate signal, and symbol FGATE is a document reading range defining gate signal.

At the time of reading a document, first, one set document is taken out by an automatic document feeder and conveyed.
It is placed on the contact glass. After that, the first carriage moves forward in a direction as indicated by an arrow (sub-scanning direction S) in FIG. 38 at a constant speed, and the second carriage follows the first carriage at a speed half that of the first carriage. Move forward. At the same time, as shown in FIG. 38, scanning is performed in the main scanning direction M. As a result, the document on the contact glass is scanned. In this state, the original on the contact glass is illuminated by a light source or the like, and the reflected light image is guided to the optical lens via the first mirror, the second mirror, and the third mirror, and the optical lens causes the reflected light image to be displayed on the image sensor. It is imaged. The image sensor photoelectrically converts the reflected light image of the formed document into an analog image signal, and the document is read.

After the document reading operation is completed, the first carriage and the second carriage return to the home position. After copying, the original on the contact glass is ejected by the automatic original feeder, and the next original set is taken out by one sheet and conveyed by the automatic original feeder to be placed on the contact glass. To be done. In this way, the reading of the document is performed one after another.

An analog image signal output from the image sensor is converted into a digital image signal by an analog / digital converter, and various image processings (binarization, multi-valued conversion) are performed on a circuit board equipped with an image processing circuit. Processing, gradation processing, scaling processing, editing processing, etc.) are performed. During the copying operation, in the printer section of the digital copying machine, the photosensitive drum is rotationally driven by the driving section so that it is uniformly charged by the charging device. The digital image signal subjected to the image processing by the image processing circuit is converted into an electrostatic image on the photosensitive drum by the laser beam scanning device. Then, after the electrostatic image on the photoconductor drum is transferred to the transfer paper, the transfer paper having the transfer image is fixed by the fixing device and discharged onto the tray as a copy.

As mentioned above, conventional digital copiers can operate to make copies of originals. By the way, in the above-described conventional image reading apparatus, in order to correct the illuminance on the image sensor surface and the output variation of each pixel of the image sensor (hereinafter referred to as “shading correction”), as shown in FIG. A white reference plate 503 is provided on a part of the back surface of 502 at an upper surface position 504 of the contact glass 501. Note that reference numeral 505 is an end portion of the left scale 502, and one end portion of the document abuts on this end portion 505. Further, in FIG. 39, reference numeral HP is a home position, and when starting reading, for example, the first mirror 5 of the first carriage
06 is located at the home position HP.

Then, in the image reading apparatus, FIG.
As shown in FIG. 39, the first carriage or the like starts moving from the home position HP in the sub-scanning direction S, and a predetermined distance Ls from the home position HP is read before reading an original document placed on the contact glass 501. Is determined, and the shading gate signal SLEA is determined.
By opening D by a predetermined width DS, the white reference plate 503
The constant width DS of is read by the image sensor. By thus reading with the image sensor, the obtained analog image signal is given to the image processing circuit to perform shading correction.

Further, in the image reading apparatus, it is determined that the distance Lf has passed from the home position HP, and the area determination gate signal FGATE for determining the original reading area is opened by the width W (for the size of the original). The reflected light image of the document is given to the image sensor to read the document. Note that the width W in FIG. 39 varies depending on the document size, the transfer paper size, the scaling factor, and the like. In addition, the home position HP (reference position as a reference in the sub-scanning direction S)
Is determined by detecting a specific position of the first carriage or the second carriage with a sensor such as a photo interrupter. Further, the image reading start position (distance Lf from the home position HP) can be adjusted in consideration of variations in the positions of the left scale 502 and the sensor (photointerrupter) that detects the home position HP, component accuracy, and the like.

On the other hand, in the conventional image reading apparatus, as shown in FIGS. 40 and 41, C on the contact glass 501 is used.
The optical axis Y read by the CD sensor 510 is the back scale 5
07, the optical axis of the lens 509, and the positional relationship of the image sensor (CCD sensor) 510. In addition, as shown in FIGS. 40 and 41, the CCD sensor 510 is inclined and fixed as shown by the arrow a direction in the drawing, or the first mirror 5 is fixed.
11, the second mirror 512, and the third mirror 513 are tilted and fixed, the CCD sensor 510 on the contact glass 501 with respect to the original reference line of the left scale 502.
Therefore, the reading optical axis Y is tilted.

It is also known that the tilting of the reading optical axis Y as described above occurs even when the position of each component changes due to the temperature change and the influence of the apparatus installation surface. If the reading optical axis Y is tilted in this way, an image 60 as shown in FIG.
Where 0 should be obtained is that the output image 601 is a parallelogram as shown in FIG. 42 (2) and the original image 610 is as the read image data 611 as shown in FIG. Become.

Further, as shown in FIG. 44, when the left scale 502 and the back scale 507 are fixed by being tilted with respect to the optical axis Y read by the CCD sensor as shown in FIG. 44, output as shown in FIG. It is also known that the image 621 is obtained in a rotated form.

[0014]

As described above, according to the conventional image reading apparatus, the reading optical axis Y by the CCD sensor 510 on the contact glass 501 is the back scale 507, the optical axis of the lens 509, and the image sensor. Since it is determined by the positional relationship of the (CCD sensor) 510, as shown in FIGS. 40 and 41, the CCD sensor 510 is indicated by an arrow a in the figure.
Fixed by tilting in the direction, or the first mirror 51
When the first, second mirror 512, and third mirror 513 are tilted and fixed, the CCD sensor 510 on the contact glass 501 with respect to the original reference line of the left scale 502.
However, there is a drawback that the reading optical axis Y is tilted.

Further, the drawback that the reading optical axis Y is tilted in this way is due to the influence of the temperature change and the apparatus mounting surface.
It also occurred when the position of each component changed. When the reading optical axis Y is tilted in this way, an image 600 as shown in FIG. 42 (1) should be obtained from a normal document, but a parallelogram output image 601 as shown in FIG. 42 (2) is obtained. And the original image 6 as shown in FIG.
There is a disadvantage that 10 becomes like parallelogram read image data 611.

Further, as shown in FIG. 44, when the left scale 502 and the back scale 507 are fixed while being inclined with respect to the reading optical axis Y by the CCD sensor as shown in FIG. As described above, there is a drawback that the output image 621 has a rotated shape.

Therefore, it is an object of the present invention to provide an image reading apparatus capable of detecting an inclination of a reading optical axis or the like based on read data from an image sensor and correcting an image based on the detected tilt. More specifically, an object of the present invention is to provide an image reading apparatus capable of detecting the tilt of the reading optical axis and the tilt of the original scale based on the read data from the image sensor and correcting the image based on the detected tilt. There is. It is another object of the present invention to provide an image reading device that performs image correction by changing the tilt of the image sensor based on the tilt detection result.

Further, according to the present invention, based on the result of the inclination detection, image reading is performed by performing parallelogram correction and / or rotation correction on read data on a frame memory, or both. The purpose is to provide a device. It is another object of the present invention to provide an image reading apparatus which performs image correction by controlling the image output tamming of the read data on the line memory based on the result of the inclination detection. .

[0019]

In order to achieve the above object, an image reading apparatus according to claim 1 exposes a document placed on a contact glass and forms a reflected light image from the document. An image reading apparatus including a first carriage for obtaining, a second carriage for guiding a reflected light image from the first carriage to an optical lens, and an image sensor for photoelectrically converting an image formed by the optical lens, An image sensor reads a display provided in the area and detects a distortion amount of an image based on the read data, and an image correction that corrects the image distortion based on the image distortion data detected by the distortion detecting unit. Means for achieving the above object.

According to a second aspect of the present invention, there is provided a strain detecting means, a display body provided at a predetermined area of a left scale disposition position at a predetermined distance, an image sensor for reading the both display bodies, and a display body from the image sensor. And a distortion amount calculating means for calculating the first image skew angle based on the read data. The distortion detecting means according to claim 3, wherein the color display body provided in a predetermined area at the back scale arrangement position, an image sensor for reading the color display body at a constant distance, and a color display body reading from the image sensor. And a distortion amount calculating means for obtaining the second image skew angle based on the data.

The image correction means according to claim 4 is a correction signal forming means for forming a correction signal for correcting the image distortion based on the distortion amount of the image from the distortion detecting means, and a correction from the correction signal forming means. And a sensor rotation mechanism for rotating the image sensor in a direction in which image distortion is corrected by a signal. The image correction means according to claim 5, further comprising: a frame memory for storing the image data from the image sensor; and a correction signal forming means for correcting the image data in the frame memory based on the distortion amount of the image from the distortion detection means. It is characterized by having. The image correction means according to claim 6 includes a line memory for storing image data from the image sensor, and a correction signal forming means for correcting the image data in the frame memory based on the amount of distortion of the image from the distortion detection means. It is characterized by having.

[0022]

In the image reading apparatus according to the first aspect of the present invention, the amount of distortion of the image is calculated based on the read data obtained when the display body provided in the predetermined area is read by the image sensor. This makes it possible to read the display object at a distance to the left scale and the back scale, and if there is a deviation in the read data when reading these, the left scale and the The inclination between the depth scale and the reading optical axis is calculated, this inclination is calculated as the distortion amount, and this distortion amount is corrected. According to the second aspect of the present invention, the inclination between the left scale and the reading optical axis is detected, and when two display bodies separated by a predetermined distance are read, a time lag occurs between these reading signals. In this case, the first image skew angle is calculated as the amount of image distortion, assuming that the left scale and the reading optical axis are tilted.

According to a third aspect of the present invention, the inclination between the back scale and the reading optical axis is detected, and when the back scale color display is read at a predetermined distance, these read signals are shifted in time. If the error occurs, it is determined that an inclination has occurred between the back scale and the reading optical axis, and the second image skew angle is calculated as the image distortion amount.
According to a fourth aspect of the present invention, the angle of the image pickup sensor is changed to correct the image, and the image pickup sensor is arranged in a direction in which the sensor rotation mechanism corrects the image distortion amount based on the image distortion amount. Is rotated about the optical axis of the lens. According to the fifth aspect of the present invention, the image data in the frame memory is corrected to correct the image, and the image data in the frame memory is corrected based on the distortion amount of the image. According to a sixth aspect of the present invention, the image data in the line memory is corrected to correct the image, and the reading or burning of the image data in the line memory is controlled based on the distortion amount of the image. Corrects the distortion.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are views for explaining a digital copying machine to which an embodiment of an image reading apparatus according to the present invention is applied, and FIGS. 4 to 14 are views for explaining a first embodiment of the present invention. Is. First, a digital copying machine to which the embodiment is applied will be described with reference to FIGS. 1 to 3, and then the first embodiment will be described with reference to FIGS. 4 and 5.

<Structure of Digital Copying Machine> FIG. 1 is an overall structure diagram of the digital copying machine, FIG. 2 is an enlarged view of an image reading apparatus of the copying machine, and FIG. 3 is an enlarged view of a printer section of the copying machine. FIG. 1, the digital copying machine is roughly composed of an image reading device 11, a printer unit 12 having a laser beam scanning device, and an automatic document feeder 13. Here, the automatic document feeder 13 conveys the set originals one by one, sets them on the contact glass 14, and discharges the originals on the contact glass 14 after completion of copying.

As shown in FIG. 2, the document reading device 11 includes a light source including an illumination lamp 15 and a reflecting mirror 16 and a first light source.
A first carriage A equipped with a mirror 17 and a second carriage B equipped with a second mirror 18 and a third mirror 19.
A color filter 20 for filtering the reflected light image sent from the second carriage B, and the color filter 20.
An optical lens 21 for forming a reflected light image that has passed through, an image sensor (CCD sensor) 22 for converting the reflected light image formed by the optical lens 21 into an analog image signal, an analog / digital converter, and an analog / digital converter. The circuit board 23 is provided with an image processing circuit for image-processing the digital image signal converted by the converter, and a cooling fan 24 for cooling the illumination lamp 15.

In this document reading device 11, when reading a document, the first carriage A moves forward at a constant speed, and the second carriage B follows the first carriage A at half the speed of the first carriage A. By moving forward, the original on the contact glass 14 is optically scanned, the original on the contact glass 14 is illuminated by the illumination lamp 15 and the reflecting mirror 16, and the reflected light image is reflected by the first mirror 17 and the second mirror 17. An image is formed on a CCD sensor 22 by a lens 21 via a mirror 18, a third mirror 19 and a color filter 20. In addition, the CCD sensor 22 photoelectrically converts the reflected light image of the formed image to output an analog image signal, and the circuit board 23 converts the image into a digital image signal for image processing. .

After the image reading is completed, the first carriage A and the second carriage B are at the home position HP.
Move back to the position. A color original can be read by using a 3-line CCD having red (R), green (G), and blue (B) filters as the CCD sensor 22. Further, in the original reading device 11, although details will be described later, in order to correct the illuminance on the surface of the CCD sensor 22 and the output variation of each pixel of the CCD sensor 22 (shading correction), the back surface of the left scale 51 is covered. White reference plate 52 at some predetermined positions
Is provided. Further, as will be described in detail later, the original reading device 11 displays a display at a position which is read prior to the reading of the white reference plate 52 and which is hidden by the left scale 51 on the contact glass 14. A body (for example, a graphic pattern 56 including the alphabet “N”) is arranged (see FIG. 2).

The printer unit 12 also forms a photoconductor drum 25 on which an electrostatic image is formed, a charging device 26 for uniformly charging the photoconductor drum 25, and an electrostatic image on the photoconductor drum 25. A laser beam scanning device 27, a developing device 28 for developing the electrostatic image formed on the photosensitive drum 25, a transfer device 30 for transferring the visible image formed on the photosensitive drum 25 onto a transfer sheet, A separation device 31 for separating the transfer paper from the photosensitive drum 25, a cleaning device 32 for wiping off the developer remaining on the photosensitive drum 25, paper feeding devices 33 to 35, and a registration roller 3.
6, a carrying device 37 for carrying the transfer paper, a fixing device 38 for fixing the visible image transferred to the transfer paper, and a tray 39 for placing a copy.

Next, details of the laser beam scanning device 27 will be described with reference to FIGS. 1 and 3. The laser beam scanning device 27 includes a semiconductor laser unit 40 fixed to the side surface of its housing, and a cylindrical lens 41 provided at a predetermined position on the output side of the semiconductor laser unit 40.
And a polygon mirror 42 provided at the center of one end side of the housing.
A polygon motor 43 for rotating the polygon mirror 42, an fθ lens 44 provided slightly on the polygon mirror 42 side from the substantially central position of the housing, and a reflecting mirror 45 provided on the other end side of the housing. The housing is composed of a dustproof glass 46 provided below the reflecting mirror 45, a synchronization detecting mirror 47 provided at one end of the reflecting mirror 45, and a synchronization detecting sensor 48 receiving reflected light from the synchronization detecting mirror 47. ing.

The overall operation of such a digital copying machine will be briefly described. <Original Reading Operation of Digital Copier> At the time of reading an original, first, one set original is taken out by the automatic original feeding device 13 and conveyed, and the contact glass 14 is fed.
Placed on top. After that, the first carriage A moves forward at a constant speed, and the second carriage B moves forward following the first carriage A at half the speed of the first carriage A. As a result, the document on the contact glass 14 is optically scanned.

The original on the contact glass 14 is illuminated by a light source or the like, and the reflected light image is reflected by the first mirror 17 and the second mirror 17.
It is guided to an optical lens 21 via a mirror 18 and a third mirror 19, and an image is formed on a CCD sensor 22 by this optical lens 21. The CCD sensor 22 photoelectrically converts the formed reflected light image of the document into an analog image signal, and the document is read. The image signal thus obtained is stored in the frame memory via the line memory. Then, after the document reading operation is completed, the first carriage A and the second carriage B return to the home position HP position. After copying,
The original document on the contact glass 14 is discharged by the automatic document feeder, and the next original document set is extracted and conveyed by the automatic document feeder and placed on the contact glass 14. In this way, the reading of the document is performed one after another.

The analog image signal output from the CCD sensor 22 is converted into a digital image signal by an analog / digital converter mounted on the circuit board 23,
The image processing circuit mounted on the circuit board 23 performs various types of image processing (binarization, multi-value processing, gradation processing, scaling processing, editing processing, etc.).

<Original Copying Operation of Digital Copying Machine> During copying operation, in the printer section 12 of the digital copying machine, the photoconductor drum 25 is rotationally driven by the driving section so that the charging device 26 uniformly charges the photosensitive drum 25. Also, the circuit board 2
The digital image signal subjected to the image processing by the image processing circuit mounted on the image forming device 3 is converted into an electrostatic image on the photosensitive drum 25 by the laser beam scanning device 27.

The operation of the laser beam scanning device 27 will be described. The laser beam emitted from the semiconductor laser in the semiconductor laser unit 40 is collimated by the collimating lens in the semiconductor laser unit 40 based on the image data read from the frame memory. Is converted into a parallel light flux by passing through the aperture provided in the semiconductor laser unit 40, and is shaped into a constant light flux. This light beam is compressed in the sub-scanning direction by the cylindrical lens 41 and enters the polygon mirror 42.

The polygon mirror 42 has an accurate polygonal shape and is rotated by a polygon motor 43 in a certain direction at a constant speed. The rotation speed of the polygon mirror 42 is determined by the rotation speed of the photosensitive drum 25, the writing density of the laser beam scanning device 27, and the number of faces of the polygon mirror 42. The laser beam entering the polygon mirror 42 from the cylindrical lens 41 is deflected by the reflecting surface of the polygon mirror and enters the fθ lens 44. The fθ lens 44 converts scanning light having a constant angular velocity from the polygon mirror 42 so that the photosensitive drum 25 scans at a constant velocity, and the laser beam from the fθ lens 44 passes through the reflecting mirror 45 and the dustproof glass 46. An image is formed on the photosensitive drum 25.

The fθ lens 44 also has a surface tilt correction function. The laser beam that has passed through the fθ lens 44 is reflected by the synchronization detection mirror 47 outside the image area and guided to the synchronization detection sensor 48. Then, a detection signal output from the synchronization detection sensor 48 provides a synchronization signal that serves as a reference for cueing in the main scanning direction. In this way, an electrostatic image is formed on the photosensitive drum 25 by the laser beam scanning device 27.

The electrostatic image on the photosensitive drum 25 is
It is transferred onto the transfer paper by the transfer device 30. After that, the transfer paper is separated from the photoconductor drum 25 by the separating device 31, and is then conveyed to the fixing device 38 by the conveying device 37. This transfer paper is fixed by the fixing device 38 and discharged onto the tray 39 as a copy. Further, the photosensitive drum 25 is cleaned by the cleaning device 32 after the transfer paper is separated, and the residual toner is removed. In this way, the digital copying machine makes a copy.

<Description of First Embodiment> FIG. 4 is a perspective view showing the relationship between the contact glass, the back scale and the left scale, which are components of the image reading apparatus. In FIG. 4, an inner scale 50 is arranged at one end of the rectangular contact glass 14, and a left scale 51 is arranged at an end orthogonal to the one end of the contact glass 14. After the document is placed on the contact glass 14 on which the back scale 50 and the left scale 51 are arranged, the scanning in the sub scanning direction S and the main scanning direction M are performed.
The original is read by the scanning of.

Here, the scanning in the sub-scanning direction S is performed while moving the carriage from the left to the right of the contact glass 14 as shown in FIG. 4, and the scanning in the main scanning direction M is performed. , FIG. 4 is performed from the top to the bottom. The contact glass 14 is shown in FIGS.
The figure explaining the positional relationship of the left scale 51 and FIG. Figure 5
6 is a rear view of the left scale 51 as viewed from the rear side, and FIG.
FIG. 7 is a cross-sectional view of the positional relationship between the contact glass 14 and the left scale 51 viewed from the main scanning direction, and FIG. 7 is a plan view of the contact glass 14.

In the document reading device 11 shown in FIGS. 2 and 4 to 7, the illuminance on the surface of the CCD sensor 22 and the CC
In order to correct the output variation of each pixel of the D sensor 22 (shading correction), a white reference plate 52 is provided at a predetermined position 54 on a part of the back surface of the left scale 51.
Reference numeral 55 is an end of the left scale 51, and the end 5
One end of the original comes into contact with the document 5. Also,
A portion of the contact glass 14 that is hidden by the left scale 51 is spaced apart from the display body by a predetermined distance (for example, a graphic pattern 56a including the alphabet "N" 56a, 5
6) is arranged.

FIG. 8 is a block diagram showing the control system of the document reading apparatus. In FIG. 8, the document reading device 11 is provided with a scanner control unit 101 including, for example, a one-chip CPU (central processing unit), and the scanner control unit 101 controls the operation in the document reading device 11. It has become so. A stepping motor 103 for moving the first carriage A and the like and a blinking circuit (switch) 105 are connected to the scanner control unit 101. The blinking circuit 105 is provided between the illumination lamp 15 and the power source 104, and the scanner control unit 1 is provided.
The blinking control signal from 01 controls the blinking of the illumination lamp 15.

Further, the scanner control unit 101 is connected with a counter 106 for counting the pulses supplied to the stepping motor 103 and an operation panel 107. Further, the scanner control unit 101 can receive a reading start command ST given from the main body. The output of the CCD sensor 22 is connected to the signal processing circuit 111. The output of the signal processing circuit 111 is connected to the analog / digital (AD) converter 112. The output of the AD converter 112 is connected to one input terminal of each of the first gate circuit 113 and the second gate circuit 114. The shading gate signal SLEAD is supplied from the scanner control unit 101 to the control input terminal of the first gate circuit 113.

The area control gate signal FGATE is applied from the scanner control section 101 to the control input terminal of the second gate circuit 114. The output terminal of the first gate circuit 113 is connected to the shading correction circuit 11
Connected to 5. The output terminal of the second gate circuit 114 is connected to the image processing circuit 116. The scanner control unit 101 includes a contact glass 14
And a display body (predetermined graphic patterns 56a, 56) provided in a portion (predetermined region) that is covered by the left scale 51 on the above.
Distortion amount calculation means 121 for obtaining image distortion based on read data obtained when CCD sensor 22 reads b).
Is provided.

In this embodiment, the distortion amount calculating means 121
And the display body (predetermined graphic patterns 56a, 56b)
The CCD sensor 22 and a partial circuit of the circuit board 23 that processes a signal from the sensor 22 constitute a strain detecting means. Further, the scanner control unit 101 of the document reading device 11 is provided with a correction signal forming unit 122 that forms an image correction signal based on the detection signal from the distortion amount calculating unit 121. This correction signal forming means 1
The sensor rotation mechanism 117 receives the correction signal thus formed.
To drive the sensor rotation mechanism 123. In this embodiment, the correction signal forming means 122,
An image correction unit is configured by the sensor rotation mechanism 123. Further, the CCD sensor 22 and the signal processing circuit 11
1, AD converter 112, shading correction circuit 115
The operation timing of the image processing circuit 116 is under the control of the scanner control unit 101.

FIG. 9 is a perspective view showing a part of the sensor rotation mechanism. FIG. 10 is a front view of the sensor rotation mechanism. In these figures, the sensor rotation mechanism 123 is configured as follows. The support 130 is a rectangular plate, and a recess 131 is formed in the center of the plate, and the lens 21 is fixed in the recess 131. A CCD drive substrate 132 on which the CCD sensor 22 is arranged is fixed to an end of the support 130. The back surface of the recess 131 of the support 130 is slidably housed in a recess 135 formed in the base 134. Springs 138, 139 are provided between both ends of the support 130 and the support pieces 136, 137 planted from the base 134.
Are provided, and both ends of the support 130 are pressed downward.

The eccentric cam 14 is provided on one end side of the support member 130 and on the opposite side to the spring 139.
The support member 130 is rotatable about the optical axis of the lens 21 by the position of the eccentric cam 140. A worm wheel 141 is fixed to the rotating shaft of the eccentric cam 140.
1 is a worm 14 fixed to the rotating shaft of the motor 142.
It is meshed with 3. The motor 142 is driven by a correction signal from the scanner control unit 101.

<Description of Operation of First Embodiment> Next, the first embodiment
11 to FIG. 1 based on FIG. 1 to FIG.
This will be described with reference to FIG. Referring to the drawings, FIG. 11 is a time chart for explaining the control operation of the scanner control section, in which the horizontal axis indicates time t and the vertical axis indicates the operation of each section. FIG. 12 shows a predetermined graphic pattern C
6 is a time chart showing an example of a signal obtained when read by the CD sensor 22, in which the horizontal axis represents time and the vertical axis represents signal level. Further, FIG. 13 is an explanatory diagram showing the relationship between the positional relationship of each element in the sub-scanning direction and the reading timing. Further, FIG. 14 is a flow chart for explaining a process for correcting the position from the relationship between the predetermined graphic pattern and the time of the read data.

[Image Distortion Detection Operation] When the reading start command ST is given from the main body to the document reading device 11 (time t
₁ ) At the same time, the scanner control unit 101 creates a reference signal (time t ₂ ) and activates the blinking circuit 105 to turn on the illumination lamp 15 (time t ₃ ). Further, the stepping motor 103 is driven to start the movement of the first carriage A and the like (time t ₄ ).

On the other hand, the scanner control unit 101 causes the counter 106 to start counting the driving pulse of the stepping motor 103 at the same time as the generation of the reference signal (time t ₄ ).
Then, the predetermined graphic patterns 56a and 56b (see FIGS. 6 and 7) arranged below the left scale 51 are read prior to the white reference plate 52. That is,
It is read by the CCD sensor 22 in a state of crossing the respective central portions of predetermined graphic patterns 56a and 56b formed of, for example, the alphabet “N” on the contact glass 14. Then, the predetermined pixel 22 of the CCD sensor 22
As for the output of a, as shown in FIG. 12, the next “L _a2 ” is output after time t _a1 from the first “L _a1 ”, and “L _a3 ” after the time t _a2 has elapsed from this “L _a2 ”. Will be output. Further, the output of the predetermined pixel 22b of the CCD sensor 22 is, as shown in FIG. 12, from the first "L _b1 " to the time t.
_The next “L _b2 ” is output after _b1, and “L _b3 ” is output after the time t _b2 has elapsed from this “L _b2 ”.

When the scanner control unit 101 compares these output patterns with the values stored in advance and the pattern using the interval of the black portion as a reference and determines that they match, the distortion amount calculation means 121 uses the distortion amount calculation unit 121 as shown in FIG. The deviation T1 of the reading time between the reading positions indicated by the symbols Sta and Stb is calculated (step 401). This reading time difference T1 has a value corresponding to the image distortion. This time difference T1 is given to the correction signal forming means 122.

The distortion amount calculating means 12 of the scanner control unit 101
1, the speed of the first carriage A is v, the pixels 22a, 2
If the distance between 2b is y and the skew angle of the image is α,
The image skew angle α is calculated using Equation 1 (step 402).

[0053]

[Equation 1] α = tan ^-1 (v · T1 / y)

The distortion amount calculating means 121 supplies this angle α to the correction signal forming means 122. [Image Correction Operation] The correction signal forming unit 122 sets an image skew correction coefficient based on the image skew angle α, forms a correction signal in the direction in which the image skew angle α disappears, and outputs the correction signal to the sensor rotation mechanism 123. To do. In the sensor rotation mechanism 123, the motor 1 is driven by the correction signal.
The rotation shaft of 42 rotates and the worm 143 rotates, whereby the worm wheel 141 rotates and the eccentric cam 140 rotates.
Rotates to rotate the CCD sensor 22 about the optical axis of the lens 21. As a result, the CCD sensor 22
Since the bias of is corrected in the normal direction, the CCD sensor 22
The position of is set to a state where there is no image distortion.

In this embodiment, the distortion amount calculating means 121 detects image distortion from the read data of the predetermined graphic patterns 56a and 56b read by the CCD sensor 22, and the correction signal forming means 122 detects the distortion of the image based on the detection signal. A correction signal is formed, and the correction signal from the correction signal forming means 122 is used to rotate the motor 142 of the sensor rotation mechanism 123 to rotate the support 130 around the optical axis of the lens 21. I am trying to correct the tilt of the axis. Therefore, the troublesomeness of skew adjustment in the manufacturing process is eliminated, and the number of working steps can be reduced.

<Description of Second Embodiment (Second Distortion Detecting Means)> FIGS. 15 and 16 are for explaining an example of the second detecting means of the present invention. FIG. 15 is a plan view showing the pattern on the contact glass, and FIG. 16 is an explanatory view showing the pattern of the read data.

[Image Distortion Detecting Operation] As shown in FIG. 15, predetermined light and shade patterns 57a and 57b are arranged on the contact glass 14 at positions where they are read prior to the white reference plate 52 of the original scale 51. As shown in FIG. 15, the predetermined light and shade patterns 57a and 57b are composed of black BL and white WT on the basis of a diagonal line of a quadrangle. When read by the CCD sensor 22 across substantially the center of each of the predetermined light and shade patterns 57a and 57b, CC
The output signals from the pixels 22a and 22b of the D sensor 22 are "L" with respect to the median value, as shown in FIG.
The pattern becomes "H" and continues.

Therefore, when the scanner control unit 101 compares these patterns with the previously stored patterns based on the density and the width and determines that they match, as shown in FIG. The time difference T1 is obtained in advance, and the image distortion amount is calculated by the distortion amount calculating means 121 from the reading time difference T1. The second
In the detection means, the image distortion amount can be calculated by using Formula 1 from the read data obtained when the predetermined light and shade patterns 57a and 57b provided on the contact glass 14 are read. By using it for skew correction, the troublesomeness of skew adjustment in the manufacturing process is eliminated. In addition, the predetermined light and shade pan 5
Misreading can be prevented by reading 7a and 57b.

<Description of Third Embodiment (Third Distortion Detecting Means)> FIGS. 17 and 18 are for explaining the third distortion detecting means. FIG. 17 is a plan view showing an example of two patterns used in this embodiment. FIG.
8 is an explanatory diagram of read data obtained by the third distortion detecting means, in which the horizontal axis represents time t and the vertical axis represents the R CCD.
The output signals of the sensor, the CCD sensor for G, and the CCD sensor for B are shown.

[Explanation of Operation of Third Distortion Detecting Means] In this third distortion detecting means, the CCD sensor 22 is for R and G.
And B for 3 line CCD. In this case, as shown in FIG. 17, the contact glass 14 is provided with predetermined color patterns 58a and 58b, which are separated from each other by a predetermined distance. The predetermined color patterns 58a and 58b
Has a specific color, and the left scale 5
1 is made of a gray material, or the background portions of the predetermined color patterns 58a and 58b are made gray. Then, the predetermined color pattern 58a,
58b is configured with blue B triangles arranged within a gray background.

Then, when the CCD sensor 22 scans across the substantially center of the predetermined color pattern 58a, the output signal of the pixel 22Ba of the CCD sensor 22B for B is at "H" level as shown in FIG. And each pixel 22R of the R and G CCD sensors 22R and 22G.
The output signals of a and 22Ra become "L" level. Similarly, when the CCD sensor 22 scans a predetermined color pattern 58b across substantially the center of FIG.
As shown in FIG. 8, the pixel 22 of the CCD sensor 22B for B
The output signal of Bb becomes "H" level, and C for R and G
Each pixel 22Rb and 22 of the CD sensors 22R and 22G
The output signal of Rb becomes "L" level.

Therefore, when the scanner control unit 101 compares these patterns with the previously stored density and width patterns and determines that they match, the optical axis at the time of reading by the CCD sensor 22 is inclined. As a result, a reading position difference T1 due to a difference in reading position is obtained as shown in FIG. 18, and the image distortion amount is calculated by the distortion amount calculating means 121 from the reading time difference T1. calculate.

In the third detecting means, the image distortion amount is
Since it can be calculated by using Equation 1 from the read data obtained when the predetermined color patterns 58a and 58b provided on the contact glass 14 are read, by using this image distortion amount data for skew correction, There is no need to worry about skew adjustment of
Misreading can be prevented by reading the predetermined color pans 58a and 58b.

<Explanation of Fourth Embodiment> [Structure of Fourth Embodiment] In the fourth embodiment, the image skew angle β is obtained by obtaining the tilt angle between the back scale and the reading line of the CCD sensor. The image distortion is corrected by correcting the data in the memory together with the image skew angle β and the image skew angle α obtained in the first embodiment. The fourth embodiment will be described with reference to FIGS. 19 to 27. FIG. 19 is a plan view showing an example in which a color inversion pattern is provided on the back scale in the fourth embodiment. FIG. 20 is a plan view showing an example in which a color reversal pattern is provided between the back scale and the contact glass. Further, FIG. 21 is a block diagram showing a control system of the fourth embodiment. FIG. 22 is a time chart showing read data obtained by reading the color inversion pattern. FIG. 23 is a flowchart for explaining the operation of setting the tilt, the image skew angle, and the skew correction coefficient.

FIG. 24 shows the image skew angle β of the same embodiment.
FIG. FIG. 25 is an explanatory diagram showing the relationship between the image skew angle α obtained in the first embodiment and the image skew angle β obtained in the fourth embodiment. FIG. 26 is an explanatory diagram of image correction according to the fourth embodiment. FIG. 27 is an explanatory diagram for explaining an example that can be corrected by the image correction of the fourth embodiment.

In the fourth embodiment, as shown in FIG. 19, a boundary line 63 is formed on the inner scale 50 by a predetermined color 61 and another color 62.
As shown in FIG. 5, the entire surface of the back scale 50 is formed with a predetermined color 65, and the back scale 50 and the contact glass 14 form a boundary 66. Further, as shown in FIG. 19, the distance between a predetermined position of the boundary 63 and another predetermined position is y ₂ . Similarly, as shown in FIG. 20, the distance between a predetermined position of the boundary 66 and another predetermined position is also y ₂ .

In the fourth embodiment, for example, as shown in FIG. 24, when the depth scale 50 is inclined by the angle β, for example, C at a predetermined position of the boundary 63 in FIG.
As shown in FIG. 22 (1), the output of the predetermined pixel of the CD sensor 22 is a signal that changes from the "H" level to the "L" level at the boundary 63, and when the distance d elapses from this point. The output of a predetermined pixel of the CCD sensor 22 is
As shown in FIG. 22 (2), at the boundary 63, a signal changing from "H" level to "L" level is obtained. Therefore, such a signal is taken into the scanner control unit 101 ′ shown in FIG. 21 via the AD converter 112. Further, the scanner control unit 101 ′ obtains the image skew angle β, forms a data correction signal together with the image skew angle β and the image skew angle α obtained in the first embodiment, and the image distortion is caused by this data correction signal. It is something to be corrected.

In FIG. 21, the scanner control unit 101 'used in the fourth embodiment differs from the scanner control unit 101 in the first embodiment in that the distortion amount calculating means 121' and the correction signal forming means 122 'are different. The point is that the processing content of is changed. Another difference of the fourth embodiment from the first embodiment is that the sensor rotation mechanism 123 is deleted. The distortion amount calculating means 121 'in the scanner control unit 101' is adapted to obtain the image skew angle α as well as the image skew angle β as in the first embodiment. Also,
The correction signal forming means 122 'in the scanner control section 101' is adapted to correct the image data in the frame memory by the image skew angles α, β from the distortion amount calculating means 121 '.

[Operation of Fourth Embodiment] Scanner control unit 1
01 'calculates the image skew angle α as in the first embodiment. Similarly, the scanner control unit 10
1'is a predetermined color 61 and another color 6 provided on the back surface of the back scale 50 installed at right angles to the left scale 51.
The CCD sensor 22 reads a predetermined position on the boundary 63 of the _{second line,} and C reads another predetermined position on the boundary 63 after the distance y _2.
It is read by the CD sensor 22.

As a result, as shown in FIG. 22, the output data of the CCD sensor 22 changes from "H" level to "L" level at a predetermined position, and after a predetermined distance d, CC
The output data of the D sensor 22 changes from "H" level to "L" level. The distance d of this level change is obtained by the distortion amount calculation means 121 ′ of the scanner control unit 101 ′ (FIG. 23).
Step 451). In addition, the distortion amount calculation means 121 ′ is
Using the relationship of the distance d with respect to the distance y _2, the image skew angle β is calculated using the following Equation 2 (step 45).
2).

[0071]

[Formula 2] β = tan ^-1 (d / y ₂ )

The image skew angle β calculated by the distortion amount calculating means 121 ′ in this way is calculated by the correction signal forming means 12
Given to 2 '. The correction signal forming means 122 ′ sets an image skew correction coefficient using this image skew angle β (step 453). In this way, as shown in FIG.
And the image skew angle β with respect to the depth scale 50 are obtained. The timing of measuring the image skew angle β is arbitrary and can be obtained by scanning at the time of power-on, factory shipment, or normal copying. The skew angles α and β obtained in this way as shown in FIG. 25 are used as values for the parallelogram correction in the correction signal forming means 122 ′, and are corrected on the frame memory to obtain a high quality image. I am trying to get it.

[Image Correction of Image Distorted in Parallelogram] Next, a case of correcting a parallelogram image will be described.
In the correction signal forming means 122 ', as shown in FIG. 26, the image distortion is corrected by changing the order of the image information to be called and written in the frame memory according to the correction value. For example, when reading the first line, the second line, the third line, ... From the frame memory,
In the fourth embodiment, as shown in FIG. 26, image correction is performed by reading each line of the frame memory 71 and performing image formation without changing the write start position.

Here, the frame memory 71 has, as shown in FIG. 26, "1", "2",
"3", ..., "8" addresses and pixels are assigned,
The second line is "9", "10", "11", ..., "1"
Address 6 "and pixels are assigned. Further, pixels are assigned to the addresses “17”, “18”, “19”, ..., “24” on the third line, and pixels are assigned to each address on and after the fourth line.

In the correction signal forming means 122 ', only the addresses "1", "2", "3" and "4" are read (written) in the first line and "9" and "1" in the second line.
0 ”,“ 11 ”,“ 12 ”,“ 5 ”,“ 6 ”,“ 7 ”,
"8", read (write), 3rd line, "1"
7 ”,“ 18 ”,“ 19 ”,“ 20 ”,“ 13 ”,“ 1 ”
4 ”,“ 15 ”, and“ 16 ”are read (written), the fourth and subsequent lines are read as described above, and processing is performed without changing the write start position. As a result, the image data 800 that has been distorted into a parallelogram before correction as shown in FIG. 27 (1) becomes normal image data 810 as shown in FIG. 27 (2).

According to the fourth embodiment, the correction coefficient is obtained from the image skew angles α and β obtained by the distortion amount calculating means 121 ′, and the correction signal forming means 12 is based on this correction coefficient.
The image data in the frame memory 71 is corrected by controlling the reading or writing of the frame memory 71 with 2 ', so that an image without distortion can be obtained.
Moreover, since it is not necessary to perform skew adjustment or the like, the number of manufacturing steps can be reduced.

<Fifth Embodiment> Next, correction of an image distorted in a rotated state according to a fifth embodiment will be described. FIG. 28 is an explanatory diagram for explaining an operation of correcting an image distorted in a rotated state by the image correction unit. FIG. 29 is an explanatory diagram showing a state in which a distorted image is corrected. In the fifth embodiment, the rotation correction is performed, but as in the case of the parallelogram image, the order of the image information read and written from the frame memory 71 is changed by the correction value, as shown in FIG. This is done by doing things. In this case, the calling position in the main scanning direction is also changed. Further, in the fifth embodiment, instead of changing the calling position in the main scanning direction, the writing position can be shifted.

Specifically, the frame memory 71 is
It is assumed that the address is assigned to the pixel for each line as in the embodiment. In such a frame memory 71, in the correction signal forming means 122 ', "1", "2", "3", "4" in the first line.
Read (write) only the address, "8" on the second line,
It reads (writes) "9", "10", "4", "5", "6", "7". In the third line, "15",
"16", "17", "11", "12", "13",
“14” is read (write), and on the 4th line, “2”
3 ”,“ 24 ”,“ 18 ”,“ 19 ”,“ 20 ”,“ 2 ”
1 ”and read (write), on the 5th line,“ 30 ”,
Read (write) with "31", "25", "26", "27", "28", and with line 6, "37", "3"
8 ”,“ 32 ”,“ 33 ”,“ 34 ”,“ 35 ”and read (write), and on the 7th line,“ 44 ”,“ 45 ”,
"39", "40", "41", and "42" are read (written), and the 8th and subsequent lines are also read (written) in the above relationship.

Thus, the read position in the sub-scanning direction is changed and the read position in the main scanning direction is also changed. By doing so, the distorted image 820 in the rotated state as shown in FIG. 29 (1) and the corrected image 830 as shown in FIG. 29 (2) can be obtained.
According to the fifth embodiment, the correction coefficient is obtained from the image skew angles α and β obtained by the distortion amount calculating means 121 ′, and the correction signal forming means 122 ′ reads out the frame memory 71 based on the correction coefficient. Alternatively, since the image data in the frame memory 71 is corrected by controlling the writing, an image without distortion can be obtained, and it is not necessary to perform skew adjustment or the like, so that the number of manufacturing steps can be reduced.

<Sixth Embodiment> Next, a sixth embodiment will be described. In the sixth embodiment, a plurality of color patterns are provided on the back scale in order to obtain the image skew angle β. FIG. 30 is a plan view showing an example in which a plurality of color patterns are provided in the lower part of the back scale. FIG. 31 is a time chart showing an example of image data obtained when this color pattern is read by the CCD sensor. As shown in FIG. 30, color patterns 75, 7 are provided at the end of the back scale 50.
6 are arranged at a distance y ₂ . The color pattern 75 has a boundary 79 formed by a red color 77 and a blue color 78. Further, the color pattern 76, like the color pattern 75, is a boundary 79 formed by a red color 77 and a blue color 78.
Is formed.

First, the scan is started and the color pattern 75 is displayed.
Is read by the CCD sensor 22, the CCD sensor for R 2
The output signal of 2 becomes "H" level at the red portion 77 of the color pattern 75 and becomes "L" level at the boundary 79. At the same time, the output signal of the CCD sensor 22 for B is "H".
The level becomes "L" level after a certain period of time (the point where the blue area 78 ends). Further, when scanning is continued and the portion of the color pattern 76 is read by the CCD sensor 22, the output signal of the R CCD sensor 22 becomes “H” level at the portion of the red color 77 of the color pattern 76, and the boundary 79 However, the output signal of the CCD sensor 22 for B becomes "H" level at the same time, and becomes "L" level after a certain period of time (the point where the area of blue color 78 ends).

Therefore, the distortion amount calculating means 121 ′ of the scanner control unit 101 has a distance d from the data of the boundary 79 of the color pattern 75 and the data of the boundary 79 of the color pattern 76.
And the image skew angle β is obtained from this distance d (see the flowchart of FIG. 23). The image skew angle β can also be obtained by disposing the color patterns 75 and 76 on the back scale 50 in this manner. According to the sixth embodiment as well, since the accurate image skew angle β is obtained, the image correction can be surely performed.

<Seventh Embodiment> This seventh embodiment is based on the image skew angle α obtained in the first embodiment and the image skew angle β obtained in the fourth embodiment. It attempts to correct image distortion by modifying the data in memory. The seventh embodiment will be described with reference to FIGS. 32 to 34. FIG. 32 is a block diagram showing the control system of the seventh embodiment. FIG. 33 is an explanatory diagram for explaining the image correction operation of the seventh embodiment. FIG. 34 is an explanatory diagram showing an example of an image that can be corrected by the image correction of the seventh embodiment.

The difference between the seventh embodiment and the fourth embodiment is that the image skew angle α obtained in the first embodiment is
And the image skew angle β obtained in the fourth embodiment is used to correct and control the data in the line memory, and other configurations are exactly the same as in the fourth embodiment. Therefore, the same reference numerals as those in the fourth embodiment are given and the description thereof is omitted.

Specifically, in the seventh embodiment, the scanner control unit 101 ″ is configured so as to control the read / write timing of the line memory 81.
This is different from the embodiment. Therefore, in the seventh embodiment, for example, the depth scale 50 in the fourth embodiment described above is used.
The boundary line 63 between the predetermined color 61 and the other color 62 provided in (see FIG. 19) is read, and then the boundary line 63 between the predetermined color 61 and the other color 62 after a predetermined distance y ₂ is read, Based on these signals, in the distortion amount calculating means 121 ′ of the scanner control unit 101 ″, the distance d from the level change at each boundary position
The image skew angle β is obtained from the distance d and the distance y _2, and the correction signal forming means 1 is formed by using the skew angle β and the image skew angle α obtained in the first embodiment.
22 "is used to obtain a correction coefficient, and the read (write) of the line memory 81 is controlled by this correction coefficient.

Here, in the line memory 81, as shown in FIG. 33, "1", "2", "3",
..., "14" address and pixels are assigned, "15", "16", "17", ..., "28" address and pixels are assigned to the second line, and "2" is assigned to the third line.
"9", "30", "31", ..., "42" and pixels are assigned, and the fourth line is "43", "4".
"4", "45", ..., "56" and pixels are assigned.

In the seventh embodiment, the correction signal forming means 122 "reads" 1 "," 2 "," 3 "," 4 "," 5 "on the first line when reading the line memory 81. "
Only the address is read (written).
5 ”,“ 16 ”,“ 17 ”,“ 18 ”,“ 19 ”,
"6", "7", "8", "9", "10" read (write) and on the third line, "29", "30",
"31", "32", "33", "20", "21",
"22", "23", "24", "11", "12",
“13” and “14” are read (written), and on the fourth line, “43”, “44”, “45”, “46”, and “4”.
7 ”,“ 34 ”,“ 35 ”,“ 36 ”,“ 37 ”,“ 3 ”
8 ”,“ 25 ”,“ 26 ”,“ 27 ”,“ 28 ”and read (write), and again on the first line,“ 1 ”,“ 2 ”,
"3", "4", "5", "48", "49", "5"
0 "," 51 "," 52 "," 39 "," 40 "," 4 "
1 ”,“ 42 ”and read (write), 2nd line,
"15", "16", "17", "18", "19",
"6", "7", "8", "9", "10", "5"
3 ”,“ 54 ”,“ 55 ”,“ 56 ”, read (write), and the following are sequentially repeated to perform processing without changing the read (write) start position. As a result, FIG. 34 (1)
As shown in FIG. 34, the image data 840 that has been distorted into a parallelogram before correction becomes normal image data 850 as shown in FIG. 34 (2).

According to the seventh embodiment, the correction coefficient is obtained from the image skew angles α and β obtained by the distortion amount calculating means 121 ′, and the correction signal forming means 12 is based on this correction coefficient.
Since the image data in the line memory 81 is corrected by controlling the reading or writing of the line memory 81 with 2 ", an image without distortion can be obtained and there is no need to perform skew adjustment or the like. The number of steps can be reduced.

<Eighth Embodiment> Next, correction of an image distorted in a rotated state according to an eighth embodiment will be described.
FIG. 35 is an explanatory diagram for explaining an operation of correcting an image distorted in a rotated state by the image correction unit. Further, FIG. 36 is an explanatory diagram showing a state in which a distorted image is corrected. In the eighth embodiment, the rotation correction is performed, but as in the case of the parallelogram image, as shown in FIG. 35, the order of the image information read and written from the line memory 81 is changed by the correction value. By doing. In this case, the calling position in the main scanning direction is also changed. In the eighth embodiment, instead of changing the reading position in the main scanning direction, the writing position may be shifted.

Specifically, the line memory 82 is shown in FIG.
As shown in, the first line is "1", "2",
Addresses “3”, ..., “8” are assigned to each pixel, and “8”, “9”, “10”, ..., On the second line.
The address "14" is assigned to each pixel, the addresses "15", "16", "17", ..., "21" are assigned to each pixel on the third line, and the fourth line is assigned. "2
Addresses "2", "23", "24", ..., "28" are assigned to each pixel.

In such a line memory 82, in the correction signal forming means 122 ",
Read (write) only addresses "1", "2", "3", 2
In the line, "8", "9", "10", "4",
“5” and read (write), “16” on the 3rd line,
"17", "11", "12", "6", "7" read (write) and on the 4th line, "23", "24",
"18", "19", "13", and "14" are read (written), and read (written) while maintaining the above relationship even after the next line. In this way, the read position in the sub-scanning direction is changed and the read position in the main scanning direction is also changed. By doing so, the distorted image 860 in the rotated state as shown in FIG. 36 (1) and the corrected image 870 as shown in FIG. 36 (2) can be obtained.

According to the eighth embodiment, the correction coefficient is obtained from the image skew angles α and β obtained by the distortion amount calculating means 121 ′, and the correction signal forming means 12 is based on this correction coefficient.
Since the image data in the line memory 82 is corrected by controlling the reading or writing of the line memory 82 by 2 ", an image without distortion can be obtained and there is no need to perform skew adjustment or the like. The man-hour is reduced.

<Ninth Embodiment> FIG. 37 is a perspective view showing a ninth embodiment. In the ninth embodiment, each of the patterns 56a, 56b to 58a, 58b shown in each of the above embodiments is used.
One of the patterns is not on the contact glass 14 but on the back surface of the left scale 51 as shown in FIG.
It is arranged as 60b. That is, on the back surface of the left scale 51, as shown in FIG.
Pattern 60a, 69 in the area to be read before 2.
b is arranged. Here, one of the patterns 60a, 60b provided on the back surface of the left scale 51 is a predetermined graphic pattern 56a, 56b such as the letter "N" as shown in FIG. When the graphic patterns 56a and 56b are read, the image skew angle α is detected based on the read data.

Further, the other one of the patterns 60a and 60b provided on the back surface of the left scale 51 is predetermined grayscale patterns 57a and 57b formed of, for example, white WT and black BL triangles as shown in FIG. When the predetermined light and shade patterns 57a and 57b are read, the image skew angle α is detected based on the read data. Further, another one of the patterns 60a and 60b provided on the back surface of the left scale 51 is predetermined color patterns 58a and 58b formed of, for example, a blue B triangle, as shown in FIG. When the color patterns 58a and 58b are read: The image skew angle α is detected based on these read data.

According to the ninth embodiment, the read data is the predetermined graphic pattern 56a provided on the left scale 51,
Since the image skew angle α can be reliably obtained by obtaining the image when 56b is read, the number of manufacturing steps can be reduced, and erroneous recognition can be prevented by reading the predetermined graphic patterns 56a and 56b. Further, according to the ninth embodiment, the read data can calculate the image skew angle α based on the data obtained when the predetermined grayscale patterns 57a and 57b provided on the left scale 51 are read, so that the manufacturing process can be performed. The trouble of adjusting the skew angle of is eliminated. Further, according to the ninth embodiment, the read data is the predetermined color pattern 58 provided on the left scale 51.
Since the image skew angle α can be calculated based on the data obtained when a and 58b are read, the complexity of adjusting the skew angle in the manufacturing process is eliminated.

Further, according to the ninth embodiment, since the predetermined patterns 60a and 60b are provided on the left scale 51, when the contact glass or the like is removed by exchanging service parts or the like in the market, the reassembling is performed again. After the left scale 5
1 does not shift. Further, in the ninth embodiment, the predetermined pattern or the predetermined color provided on the left scale 51 is formed by two-color molding, so that the left scale 51 is provided with a mark or an accessory for generating a reference signal. Processing costs, processing time, and assembly time can be reduced because there is no need to add them.

[0097]

According to the first aspect of the invention, the distortion amount of the image is calculated based on the read data obtained when the display body provided in the predetermined area is read by the image sensor, and the distortion amount is calculated. Since the image distortion is corrected based on this, it is not necessary to perform skew adjustment in the manufacturing process, and the number of manufacturing steps can be reduced. According to the invention of claim 2,
If there is a time lag in these read signals when two display bodies that are separated by a predetermined distance are read, it is considered that there is an inclination between the left scale and the reading optical axis, and the image is distorted. Since the first image skew angle is calculated as the amount, it can be used to correct the image distortion due to the tilt generated between the left scale and the reading optical axis to a normal one, and the skew adjustment work can be eliminated. . According to the third aspect of the present invention, when the color display bodies on the back scale are read at a predetermined distance, and if there is a time lag between these read signals, there is a tilt between the back scale and the reading optical axis. Since the second image skew angle is calculated as the image distortion amount, it is used to correct the image distortion due to the tilt between the left scale and the reading optical axis to a normal one. It is possible to eliminate the skew adjustment work. According to the fourth aspect of the invention, based on the distortion amount of the image, the image sensor is rotated around the optical axis of the lens in the direction in which the distortion amount is corrected by the sensor rotation mechanism. It is not necessary to do so, and the number of manufacturing steps can be reduced. According to the fifth aspect of the invention, since the image data in the frame memory is corrected based on the distortion amount of the image, it is not necessary to adjust the skew, and the number of manufacturing steps can be reduced. According to the sixth aspect of the invention, since the image distortion is corrected by controlling the reading of the image data in the line memory based on the image distortion amount, there is no need to adjust the skew, and the number of manufacturing steps is reduced. be able to.

[Brief description of drawings]

FIG. 1 is a diagram showing an entire digital copying machine to which an embodiment of the present invention is applied.

FIG. 2 is an enlarged view showing an original reading device of the digital copying machine.

FIG. 3 is a perspective view showing a configuration of a laser beam scanning device of the digital copying machine.

FIG. 4 is a perspective view showing arrangement positions of a contact glass, a left scale and a back scale in the first embodiment.

FIG. 5 is a perspective view of the left scale used in the first embodiment as viewed from the back surface side.

FIG. 6 is a cross-sectional view showing a relationship among a left scale, a contact glass, a white reference plate, and a predetermined graphic pattern used in the first embodiment.

FIG. 7 is a plan view showing a predetermined graphic pattern arranged on the contact glass used in the first embodiment.

FIG. 8 is a block diagram showing a control system used in the first embodiment.

FIG. 9 is a perspective view showing a sensor rotation mechanism used in the first embodiment.

FIG. 10 is a front view showing a sensor rotation mechanism used in the first embodiment.

FIG. 11 is a time chart for explaining the operation of the first embodiment.

FIG. 12 is a time chart showing an image signal obtained in the first embodiment.

FIG. 13 is a time chart showing a positional relationship among gate signals, a left scale, a predetermined graphic pattern, etc. obtained in the first embodiment.

FIG. 14 is a flowchart illustrating the operation of the first embodiment.

FIG. 15 is a plan view showing an arrangement state of a predetermined shade pattern according to the second embodiment.

FIG. 16 is a time chart showing pixel data obtained according to the second embodiment.

FIG. 17 is an explanatory diagram for explaining the positional relationship among the left scale, the contact glass, the white reference plate, and the predetermined color pattern in the third embodiment.

FIG. 18 is a plan view showing an arrangement state of predetermined color patterns according to the third embodiment.

FIG. 19 is a plan view showing an arrangement example of color patterns according to a fourth embodiment.

FIG. 20 is a plan view showing an arrangement example of another color pattern of the fourth embodiment.

FIG. 21 is a block diagram showing a control system of a fourth embodiment.

FIG. 22 is a time chart showing an example of image data obtained when reading a predetermined color pattern according to the fourth embodiment.

FIG. 23 is a flow chart for explaining the operation of the fourth embodiment.

FIG. 24 is an explanatory diagram of a second image skew angle calculated by the fourth embodiment.

FIG. 25 is an explanatory diagram of first and second image skew angles obtained by the fourth embodiment.

FIG. 26 is an explanatory diagram of the operation of the fourth embodiment.

FIG. 27 is an explanatory diagram showing an example of an image that can be corrected in the fourth embodiment.

FIG. 28 is an explanatory diagram of the operation of the fifth embodiment.

FIG. 29 is an explanatory diagram showing an example of an image that can be corrected in the fifth embodiment.

FIG. 30 is an explanatory diagram showing an example of a color pattern in the sixth embodiment.

FIG. 31 is a time chart showing an example of read data obtained in the sixth embodiment.

FIG. 32 is a block diagram showing a control system of a seventh embodiment.

FIG. 33 is an explanatory diagram of the operation of the seventh embodiment.

FIG. 34 is an explanatory diagram showing an example of an image that can be corrected in the seventh embodiment.

FIG. 35 is an explanatory diagram of the operation of the eighth embodiment.

FIG. 36 is an explanatory diagram showing an example of an image that can be corrected in the eighth embodiment.

FIG. 37 is a perspective view showing an example of a pattern provided in a predetermined region on the back surface of the left scale in the ninth embodiment.

FIG. 38 is an explanatory diagram showing the relationship between the contact glass of the document reading apparatus and the timings in the main scanning direction and the sub scanning direction.

FIG. 39 is an explanatory diagram showing the relationship between the position of each component and the gate signal in the sub-scanning direction in the conventional document reading apparatus.

FIG. 40 is an explanatory diagram showing a back scale, a left scale, a contact glass, and a reading optical axis in a conventional document reading apparatus.

FIG. 41 is a first carriage and a second carriage of a conventional document reading apparatus.
FIG. 3 is a perspective view showing a relationship between a carriage, a lens, and an image sensor.

FIG. 42 is an explanatory diagram for explaining that the image is distorted due to the shift of the optical axis in the conventional document reading apparatus.

FIG. 43 is another explanatory diagram for explaining that the image is distorted due to the deviation of the optical axis in the conventional document reading apparatus.

FIG. 44 is an explanatory diagram showing the relationship between the back scale, the left scale, the contact glass, and the reading optical axis in the conventional document reading apparatus.

FIG. 45 is an explanatory diagram for explaining that the image is distorted due to the shift of the optical axis in the conventional document reading apparatus.

[Explanation of symbols]

 11 Document Reading Device 12 Printer Section 13 Automatic Document Feeding Device 14 Contact Glass 15 Illumination Lamp 16 Reflecting Mirror 17 First Mirror 18 Second Mirror 19 Third Mirror 21 Optical Lens 22 CCD Sensor (Imaging Sensor) 23 Circuit Board 25 Photosensitive Drum 26 Charging Device 27 Laser Beam Scanning Device 28 Developing Device 30 Transfer Device 31 Separation Device 38 Fixing Device A First Carriage B Second Carriage 50 Back Scale 51 Left Scale 52 White Reference Plate 54 Top Surface Position 55 Edge 56 Predetermined Graphic Pattern 57 Predetermined light and shade pattern 58 Predetermined color pattern 60 Pattern 61, 62, 64 colors 63, 65 Boundary 71 Frame memory 81, 82 Line memory 101 Scanner control unit 103 Stepping motor 105 Flashing circuit 106 Counter 107 Operation Panel 111 signal processing circuit 113 first gate circuit 114 and the second gate circuit 115 the shading correction circuit 116 the image processing circuit 121, 121 'distortion amount calculating means 122, 122', 122 "correction signal forming means 123 sensor rotation mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Kimura 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (6)

[Claims] 1. A first carriage for exposing a document placed on a contact glass to obtain a reflected light image from the document, and a second carriage for guiding the reflected light image from the first carriage to an optical lens. In an image reading device including an image sensor that photoelectrically converts an image formed by the optical lens, a display body provided in a predetermined area is read by the image sensor, and a distortion amount of the image is detected based on the read data. An image reading apparatus comprising: a distortion detecting unit that performs the image distortion correction; and an image correcting unit that corrects the image distortion based on the image distortion data detected by the distortion detecting unit. 2. The distortion detecting means is based on a display body provided at a predetermined area of a left scale arrangement position with a certain distance, an image sensor for reading both display bodies, and display body read data from the image sensor. The image reading apparatus according to claim 1, further comprising: distortion amount calculating means for obtaining the first image skew angle. 3. The distortion detecting means, a color display body provided in a predetermined region at a rear scale arrangement position, an image sensor for reading the color display body at a constant distance, and color display body read data from the image sensor. The image reading apparatus according to claim 1, further comprising: a distortion amount calculating unit that obtains a second image skew angle based on the above. 4. The image correction means includes a correction signal forming means for forming a correction signal for correcting the image distortion based on the distortion amount of the image from the distortion detecting means, and a correction signal from the correction signal forming means. The image reading apparatus according to claim 1, further comprising: a sensor rotation mechanism that rotates the image sensor in a direction in which image distortion is corrected. 5. The image correction means includes a frame memory for storing image data from the image sensor, and a correction signal forming means for correcting the image data in the frame memory based on the distortion amount of the image from the distortion detection means. The image reading apparatus according to claim 1, further comprising: 6. The image correction means includes a line memory for storing image data from the image sensor, and a correction signal forming means for correcting the image data in the frame memory based on the distortion amount of the image from the distortion detection means. The image reading apparatus according to claim 1, further comprising: