JPH04334164A - Picture reader - Google Patents

Abstract

PURPOSE:To attain accurate shading correction by moving both an optical system and a reference body to make the optical system and the reference body in close contact with each other at the correction of read. CONSTITUTION:A read roller 4 is reversed for shading correction and a sensor unit 13 in press contact with a read roller 4 is rocked around a fitting shaft 14 and a read position of a sensor unit 12 is moved on a white color reference board 7. When the sensor unit 13 is rocked, a space is caused between the white color reference board 7 and an original face of the sensor unit 13, the white color reference board 7 is driven by a force of a plate spring 15 around a shaft of the roller 4 and the sensor unit 13 and the white color reference board 7 keep a contact at all times. Thus, accurate shading correction is implemented.

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, and more particularly to an image reading apparatus that reads a sheet-like original by moving the original.

0002

2. Description of the Related Art FIG. 17 shows an example of the basic configuration of a conventional device of this type to which the present invention pertains, and FIGS.
shows a schematic diagram of the vicinity of the sensor unit.

[0003] In other words, this device is capable of handling a plurality of original documents 10.
a paper feed guide 102 for stacking the originals 101, a pre-conveyance roller 103 for transporting the stacked originals 101 to the separating section, and a paper feed guide 102 for loading the originals 101;
01 into sheets one by one and conveys them to the reading roller 104 which also serves as a document reading position.
A white reference plate 107 for shading correction that also serves as a paper guide to guide the original 101 to the original 101
Paper ejection roller 108 and paper ejection roller 109 for ejecting
It is composed of

[0004] Also, the original glass 110 and the lens 111
A sensor unit 113 integrally composed of a sensor 112 and a light source 123 is pressed against the reading roller 104 by a spring 115, and is rotated in the normal and tangential directions with respect to the point of contact with the reading roller 104 by a fitting shaft 114. It is positioned so that it can swing.

Here, the pressure contact point of the spring 115 is on the normal line to the contact point between the sensor unit 113 and the reading roller 104.

By the way, in general, in an image reading device composed of an optical system consisting of a light source, a lens, and a sensor, even when reading an original with uniform density, the line of the sensor may vary due to variations in the light source, optical characteristics of the lens, etc. Uniform output cannot be obtained in all directions, and as a result, even if a document with uniform density is read, information as a uniform density cannot be obtained and density unevenness occurs. For this reason, conventionally, before reading a document, a white reference plate 7 of uniform density is read, a data correction coefficient is determined so that the data value becomes a constant value, and the read data is corrected (
(hereinafter referred to as shading correction).

When a reading start signal is sent from a host computer (not shown), the reading roller 104 is first reversed in order to perform shading correction. When the reading roller 104 reverses, the reading roller 104
The sensor unit 113, which is pressed into contact with the
The reading position moves onto the white reference plate 107.

When the sensor unit 113 swings to the position of the white reference plate 107 and is stopped by the swing stop A16 provided on the sensor unit 113, the frictional force between the sensor unit 113 and the reading roller 104 increases. As a result, a torque limiter (not shown) is cut off and the swinging of the reading roller 104 is also stopped.

As a result, the original 1 is separated into sheets one by one by the separating section and sent to the reading position on the reading roller 104.
01 hits the stopped reading roller 104, the document 101 forms a loop, and the edge of the document 101 aligns the registration at the leading edge of the document.

After determining the shading correction coefficient, the reading roller 104 rotates in the normal direction, and the sensor unit 113 pressed against the reading roller 104 swings around the fitting shaft 114 and reaches the reading position on the document reading roller 104. Sensor unit 113 moves.

When the sensor unit 113 reaches the reading position on the document reading roller 104, the sensor unit 11
The swing is stopped by a swing stopper 117 provided at 3, and reading of the original 101 is started.

Reading of the original 101 is performed in synchronization with an original reading signal sent line by line from the host computer, and the reflected light from the original 101 illuminated by the light source 123 is imaged by the lens 111 on the sensor 112. The signal is converted into an electrical signal by the sensor 112 and then sent to the host computer.

The document 101, on which information has been sequentially read line by line by handshaking, is discharged to the outside of the main body via a discharge roller 108.

[0014]

However, in these conventional image reading devices, when reading the white reference plate 7, the sensor unit 1 is
3 and the white reference plate 7 are not in close contact with each other (see FIG. 19), a sensor with a shallow reading depth cannot perform accurate image reading, making it difficult to perform shading correction accurately.

Furthermore, by abutting the original against the reading roller 4, the original 1 is looped and the registration of the leading edge of the original is guaranteed. has been reached, and the original 1 cannot be read while the reading position of the sensor unit 13 is moved from the white reference reading position to the original reading position on the reading roller 4 after determining the shading correction coefficient. First, there is a drawback that the leading edge of the document is lost because the document 1 is transported.

Furthermore, in these conventional devices, the pressure contact point of the spring 15 that presses the sensor unit 13 against the reading roller 4 is provided on the normal line to the contact point between the sensor unit 13 and the reading roller 4.

Therefore, when the sensor unit 13 is to be swung in the document conveyance direction during document reading, the combined force of the sensor unit 13's own weight and the spring pressure applied to the sensor unit 13 is used to assist the oscillation of the sensor unit 13. Since it acts as a moment, it is possible to reliably swing the sensor unit 13 even if the frictional force generated between the sensor unit 13 and the reading roller 4 is small. In order to swing, the frictional force generated between the sensor unit 13 and the reading roller 4 is caused by the weight of the sensor unit 13, the swinging load of the sensor unit 13, the spring pressure applied to the sensor unit 13, etc., contrary to the above. A load greater than the combined load is required, and there is a risk that accurate reading correction may not be possible.

However, when the coefficient of friction between the sensor unit 13 and the reading roller 4 increases, the reading roller 4
Since the torque required by the motor that drives the motor increases, a large motor or a high-performance motor must be used, which has the disadvantage of increasing costs.

Furthermore, as the coefficient of friction between the sensor unit 13 and the reading roller 4 increases, the amount of wear on the reading roller 4 also increases, and the reading roller 4 must be made of a special material with wear resistance, which also reduces costs. It was connected to the up.

It is also possible to increase the frictional force by increasing the contact force between the sensor unit 13 and the reading roller 4, but since the load when the sensor unit 13 swings also increases, no effect can be expected. Even if the rocking was performed reliably, it would still have the same drawbacks as mentioned above.

As another conventional example, as shown in FIG. 20, the document glass 110 is configured to move parallel to the sensor unit 113 due to friction as the reading roller 104 rotates in the forward and reverse directions. 110
A white reference 120 is provided above.

Then, when a reading start signal is sent from a host computer (not shown), the reading roller 104 is first reversed in order to perform shading correction. When the reading roller 104 reverses, the original glass 110 pressed against the reading roller 104 moves in parallel due to frictional force, and the original glass 1 moves to the reading position of the sensor unit 113.
When the white reference 120 provided on the white reference 120 moves, the document glass 9 is stopped by positioning (not shown) and shading correction is started (see FIG. 21).

When the shading correction coefficient is determined, the reading roller 104 rotates in the normal direction, and the original glass 110 pressed against the reading roller 104 moves parallel to the white reference 120.
moves away from the reading position and starts reading the original 101.

Here, the original glass 110 has a white reference 12
When 0 retreats from the reading position, it is also regulated by positioning (not shown) and its movement is stopped (see FIG. 22).

However, since the white reference 120 used as a reference for shading correction moves from the reading position during image reading, shading correction is only performed immediately before reading the original.

Therefore, if the light intensity of the light source 123 changes due to changes in the environmental temperature or the output value of the sensor 112 changes during reading, the actual desired shading waveform and the shading waveform read during correction may differ. There will be confusion between them. As a result, even if a document with a uniform density is read, the density of the document changes midway through, resulting in a problem that the actual document cannot be read faithfully.

The present invention has been made to solve the problems of the prior art described above, and its object is to provide an image reading device that can perform shading correction more accurately.

Another objective is to reduce the size of missing readings.

Another object of the present invention is to ensure the rocking of the optical system with a simple configuration.

Furthermore, it is possible to read the original image more faithfully in accordance with environmental changes during reading.

[0031]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a light source for irradiating an original;
The optical system includes a lens that forms an image of the reflected light from the original illuminated by the light source, and an image sensor that reads the original image formed by the lens, and is used as a reference when optically reading the original. In an image reading device that reads a body and performs correction related to the optical reading, both the reference body and the optical system are configured to be movable, and when the reference body is read, the reference body and the optical system are movable. The reference body is characterized in that the systems are configured to move closer to each other and read the reference body.

[0032] The present invention is also characterized in that the reference body and the optical system are in close contact with each other when reading the reference body.

[0033] Furthermore, it is preferable that the reference body also serves as a document guide.

Furthermore, a light source for illuminating the original, a lens for forming an image of the reflected light from the original illuminated by the light source, and an image sensor for reading the image of the original formed by the lens are integrated. When optically reading a document, the optical system is oscillated by friction with a roller for conveying the document to read a reference body and perform correction related to optical reading. The image reading apparatus is characterized in that means is provided for applying a moment for assisting swinging to the swinging direction of the optical system when reading a reference object.

[0035] Furthermore, it is preferable that the point of application of the force that presses the optical system against the roller is provided at a portion that does not change with respect to the direction of pressure contact between the roller and the optical system when the optical system is oscillated.

Furthermore, another invention includes a light source for illuminating a document, a lens for forming an image of reflected light from the document illuminated by the light source, and an image sensor for reading the document imaged by the lens. In an image reading device, the image reading device has an optical system configured to read a reference body by moving the optical system or a reference body when optically reading a document, and performs correction related to the optical reading, A part of the reference body is permanently provided within the effective reading range of the image sensor and outside the document reading area, and the reference body is configured to be read even when reading the document.

[0037]

[Operation] In the present invention, not only the optical system for reading the original but also the reference body itself which is the reference for shading correction are made movable, and the optical system and the reference body are kept in contact even during reading correction. It becomes possible to perform accurate correction.

Furthermore, by moving the optical system and the reference body closer to each other, the actual amount of movement of the optical system between the reading position of the reference body and the document reading position can be reduced.
It is also possible to reduce the size of missing reading of the document.

Furthermore, by configuring the optical system so that a moment for supporting the rocking is applied to the rocking direction of the optical system during correction, even when the coefficient of friction between the optical system and the reading roller is small, the optical system can be operated reliably. Becomes swingable.

Furthermore, even if the pressure applied to the optical system is increased,
It becomes possible to reliably swing the optical system.

Furthermore, by widening the effective reading range of the optical system with respect to the original, a part of the reference body for shading correction is always present outside the reading range of the original, and the light intensity of the light source during image reading is reduced. By making it possible to measure changes, the correction of the correction coefficient is carried out sequentially.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 schematically show the structure of the vicinity of a sensor unit of an image reading apparatus according to a first embodiment of the present invention. In other words, this image reading device reads a plurality of original documents 1.
a paper feed guide 2 for stacking documents 1, a pre-conveyance roller 3 for transporting the stacked documents 1 to a separating section, and a feeder for separating the documents 1 one by one and conveying them to a reading roller 4 which also serves as a document reading position. A separating section composed of a paper roller 5 and a retard roller 6, a white reference plate 7 for shading correction that also serves as a paper guide for guiding the original 1 to the reading roller 4, and a paper ejection roller for ejecting the original 1. 8 and a paper discharge roller 9.

Further, a sensor unit 13 which is integrally constituted by an original glass 10, a lens 11, a sensor 12 and a light source 23 is pressed against the reading roller 4 by a spring 15, and is prevented from coming into contact with the reading roller 4 by a fitting shaft 14. It is positioned so that it can swing in the normal and tangential directions with respect to the point. On the other hand, the white reference plate 7, which serves as a reference body for shading correction and also serves as a paper guide for guiding the document 1 to the reading roller 4, is configured to be able to swing around the swing axis of the reading roller 4 as a fulcrum. , a sensor unit 13 as an optical system by a plate spring 19 provided on a base 18.
is being forced to.

When a reading start signal is sent from a host computer (not shown), the reading roller 4 is first moved in order to perform shading correction as in the conventional example.
is reversed, the sensor unit 13 pressed against the reading roller 4 swings about the fitting shaft 14 as a fulcrum, and the reading position of the sensor unit 13 moves onto the white reference plate 7.

When the sensor unit 13 swings, a space is created between the white reference plate 7 and the document surface of the sensor unit 13, but the white reference plate 7 rotates around the axis of the reading roller 4 and rotates the leaf spring 15. Since the sensor unit 13 and the white reference plate 7 are rotated by force, the sensor unit 13 and the white reference plate 7 are always in contact with each other.

Furthermore, since the white reference plate 7 also rotates as the sensor unit 13 swings, the opening angle of the paper guide widens, making it easier to guide the original 1 to the reading roller 4, and to remove the registration at the leading edge of the original. The space for the loop created is also wider.

After determining the shading correction coefficient, the reading roller 4 rotates normally and the sensor unit 13 to which it is pressed,
The white reference plate 7 is moved around the fitting shaft 14 to the original reading position on the reading roller 4, but the white reference plate 7 is pushed by the sensor unit 13 and rotates around the 4 axes of the reading roller, and is moved from the original reading position of the sensor unit 13. fall back.

Furthermore, the reading position of the sensor unit 13 and the white reference plate 7 are moved relative to each other during shading correction, so that the amount of movement of the sensor unit 13 is halved compared to the conventional example. From then on,
As in the conventional example, the document 1 whose information has been sequentially read line by line by handshaking is ejected to the outside of the main body via the ejection roller 8. [Other Embodiments] FIGS. 3 and 4 show a schematic configuration of the vicinity of a sensor unit according to a second embodiment of the present invention. Note that the basic configuration and basic operation of the present invention are the same as those of the conventional embodiments.

In this embodiment, the original 1 is placed on the reading roller 4.
A white reference plate 7 for shading correction, which also serves as a paper guide for guiding the image, is attached to the sensor unit 13 so as to be able to slide back and forth in the document conveyance direction in contact with the sensor unit 13. It is tensioned by a coil spring 24.

When a signal to start reading is sent from a host computer (not shown), in order to perform shading correction as in the conventional example, first, the reading roller 4 is reversed and the sensor unit 13, which is in pressure contact with the reading roller 4, is fitted. The reading position of the sensor unit 13 moves onto the white reference plate 7 by swinging about the joint shaft 14 as a fulcrum.

Here, when the sensor unit 13 swings, the white reference plate 7 integrated with the sensor unit 13 also swings. When the sensor unit 13 is at the document reading position on the reading roller 4, the swing stopper 21 provided on the white reference plate 7 moves toward the boss 2 provided on the side plate of the main body (not shown).
2, the white reference plate 7 is configured to be unable to move to the document reading position on the reading roller 4. However, as the sensor unit 13 swings, the coil spring 24 provided on the sensor unit 13 The white reference plate 7 moves to the reading position of the sensor unit 13.

Furthermore, since the white reference plate 7 also swings as the sensor unit 13 swings, the opening angle of the paper guide widens, making it easier to guide the original 1 to the reading roller 4, and also making it possible to register the leading edge of the original. There is also more space for loops that can be inserted.

After determining the shading correction coefficient, the reading roller 4 rotates normally and the sensor unit 13 to which it is pressed is
The sensor swings around the fitting shaft 14 and moves to the original reading position on the reading roller 4. When the sensor unit 13 reaches the original reading position on the reading roller 4, the rocking stop B17 provided on the sensor unit 13 is moved in the same way as when reversing the rotation.
The swinging of the sensor unit 13 is regulated, the swinging of the sensor unit 13 is stopped, and reading of the original 1 is started.

At this time, the swing stop 21 provided on the white reference plate 7 is also regulated by the boss 22, and the white reference plate 7 is moved back from the reading position of the sensor unit 13, so that the original 1 can be read.

Furthermore, since the reading position of the sensor unit 13 and the white reference plate 7 move relative to each other so as to approach each other during shading correction, the amount of movement of the sensor unit 13 is halved compared to the conventional example.

Thereafter, as in the conventional example, the document 1 whose information has been sequentially read by handshaking line by line is ejected to the outside of the main body via the ejection roller 8.

FIGS. 6 and 7 show schematic diagrams of the vicinity of a sensor unit according to a third embodiment of the present invention. Note that the basic configuration and basic operation of the present invention are the same as those of conventional devices of this type.

In this embodiment, the pressure contact point of the spring 15 that presses the sensor unit 13 against the reading roller 4 moves in the direction of the discharge roller 8 with respect to the normal line at the contact point between the sensor unit 13 and the reading roller 4. I've let it happen. When a signal to start reading is sent from a host computer (not shown), the reading roller 4 is first reversed in order to perform shading correction as in the conventional example, and the sensor unit 13, which is in pressure contact with the reading roller 4, moves the fitting shaft 14. Swings on a fulcrum,
The reading position of the sensor unit 13 moves onto the white reference.

At this time, the spring 1 for pressure contacting the sensor unit 13
Since the pressure contact point of the sensor unit 13 is moved toward the paper ejection roller 8 side, the sensor unit 13
A moment acts to help swing the sensor unit 13, and even if the frictional force between the sensor unit 13 and the reading roller 4 is small, the sensor unit 13 can be rocked reliably.

In addition, when the coefficient of friction force of the reading roller 4 is small, the sensor unit 1 is used to increase the document conveying force.
Even if the pressure contact force of the spring 15 for triple pressure contact is increased, the moment for assisting the swinging of the sensor unit 13 also increases in proportion to the increase in the pressure contact force, so that the sensor unit 13 can reliably swing.

FIG. 8 shows a schematic diagram of the vicinity of the sensor unit 13 according to the fourth embodiment of the present invention. Note that the basic configuration and basic operation of the present invention are the same as those of conventional devices of this type.

In this embodiment, similarly to the third embodiment, the pressure contact point of the spring 15 that presses the sensor unit 13 against the reading roller 4 is located between the sensor unit 13 and the reading roller 4.
The paper discharge roller 8 is moved in the direction of the normal line at the contact point.

Furthermore, in this embodiment, the pressure contact point of the spring 15 for pressure contact of the sensor unit 13 is provided at a portion that does not change with respect to the pressure contact direction of the spring 15 when the sensor unit 13 swings.

Therefore, when the sensor unit 13 swings, the pressure force of the spring 15 does not change during document reading or shading reading, and the dead weight of the sensor unit 13, which was a load during the swing, is reduced. Since fluctuations in the spring pressure applied to the sensor unit 13, such as the sliding load of the sensor unit 13 and the spring pressure applied to the sensor unit 13, are eliminated, it is possible to reduce the swinging load.

FIGS. 9 and 10 show schematic diagrams of the vicinity of the sensor unit 13 according to the fifth embodiment of the present invention. Note that the basic configuration and basic operation of the present invention are the same as those of conventional devices of this type.

In this embodiment, a force is applied to the sensor unit 13 by a spring 15 for pressing the sensor unit 13 against the reading roller 4 and a coil spring 24 for pulling the sensor unit 13 in the swinging direction when reading the white reference. In addition, the normal direction at the contact point between the sensor unit 13 and the reading roller 4 and the sensor unit 1
The direction in which the spring 15 is pressed against the reading roller 4 is the same as in the conventional example.

When a reading start signal is sent from a host computer (not shown), the reading roller 4 is reversed to perform shading correction as in the conventional example, and the reading position of the sensor unit 13 is moved onto the white reference. At this time, since the sensor unit 13 is provided with a coil spring 24 for assisting the swinging of the sensor unit 13, it assists the swinging of the sensor unit 13 in the swinging direction of the sensor unit 13, unlike conventional devices. As a result, the sensor unit 13 can be reliably swung even if the coefficient of friction between the sensor unit 13 and the reading roller 4 is small.

Furthermore, if the document conveyance force of the reading roller 4 is small, it may be possible to increase the document conveyance force;
Even if the pressing force of the spring 15 for pressing the sensor unit 13 is increased, the tensile force of the coil spring 24 is increased accordingly to increase the auxiliary force.
can be rocked reliably.

FIGS. 11 and 12 are schematic views of the vicinity of the white reference in the seventh embodiment of the present invention. Note that the basic configuration and basic operation of this embodiment are the same as those of the conventional embodiment.

In this embodiment, the white reference 15 on the upper surface of the original glass 9, which is configured to be movable in parallel in the original reading direction as in the conventional apparatus, has an end that is outside the reading range of the original 1 and is located close to the sensor. 11 It is bent into an L-shape within the effective reading range.

When an image reading signal is sent from a host computer (not shown), the white reference 15 moving on the document reading line is read by the sensor 11, and the shading correction is performed so that the output is uniform. A correction value is determined.

That is, when a reading start signal is sent from a host computer (not shown), the reading roller 4 rotates in reverse to perform shading correction, and moves the white reference provided on the original glass 9 to the reading position of the sensor unit 13. 15 moves to determine the shading correction coefficient (see FIG. 1). After determining the shading correction coefficient, the reading roller 4 rotates normally, the original glass 9 moves in parallel, the white reference 15 retreats from the reading position, and reading of the original 1 is started (see FIG. 2).

At this time, a part of the white reference 15 that is outside the reading range of the original 1 is within the effective reading range of the sensor 11, so that changes in the amount of light from the light source 12 can be detected at all times, and changes in the amount of light can be detected. The shading correction coefficient is electrically configured to constantly correct the shading correction coefficient determined before the start of document reading.

[0074] The original 1, on which information has been sequentially read line by line by handshake, is ejected to the outside of the main body via the ejection roller 7.

FIGS. 13 and 14 each show a schematic view of the vicinity of the white reference in the eighth embodiment of the present invention. The basic configuration and basic operation of this embodiment are the same as those of the first embodiment.

In this embodiment, as in the first embodiment, the white reference 15 whose end is bent in an L shape at a portion outside the reading range of the original 1 and within the effective reading range of the sensor 11 is It is provided on the reading roller side of the document glass 9, which is configured to be movable in parallel in the reading direction.

When a reading start signal is sent from a host computer (not shown), the reading roller 4 is reversed to perform shading correction, and the white reference 15 provided on the document glass 9 is moved to the reading position of the sensor unit 13. Determine the shading correction coefficient (see FIG. 13). At this time, since the white reference 15 is provided at the original reading position, that is, at the focal plane of the lens 10, more accurate shading correction can be performed than in the above example. After determining the shading correction coefficient, the reading roller 4 rotates forward, the original glass 9 moves in parallel, the white reference 15 retreats from the reading position, and reading of the original 1 begins (see FIG. 14). At this time, manuscript 1
Since a part of the white reference 15 that is outside the reading range of the sensor 11 is within the effective reading range of the sensor 11, changes in the light intensity of the light source 12 can be detected at all times. The shading correction coefficient is electrically configured to constantly correct the shading correction coefficient. Also, the length of the reading roller 4 is the white standard 15 at the time of reading.
Since the white reference 15 is set shorter than the position , the white reference 15 will not deteriorate due to friction with the reading roller 4 when reading the original 1. The document 1, on which information has been sequentially read line by line by handshake, is ejected to the outside of the main body via the ejection roller 7.

FIGS. 15 and 16 show schematic views of the vicinity of the sensor unit and the vicinity of the white reference, respectively, according to the ninth embodiment of the present invention. The basic configuration and basic operation of this embodiment are the same as those of the conventional embodiment.

In this embodiment, a white reference 15 for shading correction is provided on a paper guide 16 for guiding the original 1 to the reading roller 4. Further, a sensor unit 13 in which a document glass 9, a lens 10, a sensor 11, and a light source 12 are integrated is pressed against the reading roller 4 by a spring 14, and is brought into contact with the reading roller 4 by a fitting shaft 17. It is positioned so that it can swing in the normal and tangential directions.

For this reason, when a reading start signal is sent from a host computer (not shown), the reading roller 4 is first reversed in order to perform shading correction. When the reading roller 4 reverses, the sensor unit 13 pressed against the reading roller 4 swings about the fitting shaft 17 due to frictional force, and the reading position of the sensor unit 13 moves onto the white reference 15. The sensor unit 13 swings to the position of the white reference 15, and is stopped by a swing stop A18 provided on the sensor unit 13.

After determining the shading correction coefficient, the reading roller 4 rotates normally, and the sensor unit 13 pressed against the reading roller 4 swings around the fitting shaft 17 to place the sensor at the reading position on the original reading roller 4. Unit 13 moves.

When the sensor unit 13 reaches the reading position on the document reading roller 4, the swing stop A19 provided on the sensor unit 13 restricts the swing and stops, and the document 1 is stopped.
Start reading.

At this time, the end of the paper guide 16, including a part of the white reference 15, has sunk into the original reading position at a portion outside the reading range of the original 1 and within the effective reading range of the sensor 11, and is constantly exposed to the light source. 12 changes in the amount of light can be detected.

For this reason, the apparatus is electrically configured to constantly correct the shading correction coefficient determined before the start of document reading in accordance with changes in the amount of light. The document 1, on which information has been sequentially read line by line by handshake, is ejected to the outside of the main body via the ejection roller 7.

[0085]

[Effects of the Invention] The present invention has the above configuration, and by configuring the optical system and the reference body to be moved, it is possible to bring the optical system and the reference body into close contact during correction for reading. , accurate correction becomes possible.

Furthermore, by mutually moving the optical system and the reference body, the amount of movement of the optical system is reduced, and the unreadable area that occurs while the reading position of the optical system moves from the reference body reading position to the document reading position. Edge chipping of the original in some areas is also reduced.

Furthermore, when the reference body also serves as a document guide, moving the reference body increases the angle of the document guide, which increases the space for creating a loop for registering the document, and improves the conveyance of the document. It also has the effect of improving.

Furthermore, by setting the point of action of the spring load on the optical system so that a positive moment is applied to the swinging direction of the reference body of the optical system when reading, the sensor can be maintained even when the spring load is increased. It becomes possible to reduce the swing load.

Furthermore, even if the coefficient of friction between the reading roller and the optical system is low, there is no need to increase the spring pressure load, so it is possible to improve the wear resistance of the reading roller.

In addition, by forming the reference body for correction within the reading range of the optical system and outside the reading size of the original, it is possible to read the reference body even when reading the original, and image reading is improved. Changes in the correction coefficient due to changes in the amount of light during the process can be changed even during image reading, making it possible to read an image that is faithful to the original without density fluctuations during reading.

Furthermore, by configuring the reference body to be read at the document reading position of the optical system, that is, at the image formation point of the lens, it becomes possible to perform even more accurate correction.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the vicinity of a sensor unit of an image reading device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the vicinity of a sensor unit during shading correction according to the first embodiment of the present invention.

FIG. 3 is an overall configuration diagram of the image reading device shown in FIG. 1;

FIG. 4 is a schematic diagram of the vicinity of a sensor unit of an image reading device according to a second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of the vicinity of a sensor unit during shading correction according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram of the vicinity of a sensor unit of a document reading device according to a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of the vicinity of a sensor unit during shading reading according to a third embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of the vicinity of a sensor unit according to a fourth embodiment of the present invention.

FIG. 9 is a schematic configuration diagram of the vicinity of a sensor unit when reading a document according to a fifth embodiment of the present invention.

FIG. 10 is a schematic configuration diagram of the vicinity of a sensor unit during shading reading according to a sixth embodiment of the present invention.

FIG. 11 is a schematic diagram of the vicinity of the white reference during shading reading according to the seventh embodiment of the present invention.

FIG. 12 is a schematic diagram of the vicinity of a white reference when reading a document according to a seventh embodiment of the present invention.

FIG. 13 is a schematic diagram of the vicinity of the white reference during shading reading according to the eighth embodiment of the present invention.

FIG. 14 is a schematic diagram of the vicinity of a white reference when reading a document according to an eighth embodiment of the present invention.

FIG. 15 is a schematic diagram of the vicinity of a sensor unit according to a ninth embodiment of the present invention.

FIG. 16 is a schematic diagram of the vicinity of a white reference according to a ninth embodiment of the present invention.

FIG. 17 is a schematic configuration diagram of a conventional image reading device.

FIG. 18 is a schematic configuration diagram of the vicinity of a sensor unit during image reading of a conventional image reading device.

FIG. 19 is a schematic configuration diagram of the vicinity of a sensor unit during shading correction of a conventional image reading device.

FIG. 20 is a schematic configuration diagram of another conventional device of this type.

FIG. 21 is a schematic diagram of the vicinity of a white reference during shading reading in a conventional device of this type.

FIG. 22 is a schematic diagram of the vicinity of a white reference when reading a document in a conventional device of this type.

[Explanation of symbols]

1 Manuscript 4 Reading roller 7 White reference plate 10 Original glass 11 Lens 12 Image sensor 13 Sensor unit (optical system) 14 Fitting shaft 15 Spring 23 Light source 120 White standard

Claims (6)

[Claims] 1. An optical system comprising a light source for illuminating a document, a lens for forming an image of reflected light from the document illuminated by the light source, and an image sensor for reading the document image formed by the lens. In an image reading device that reads a reference body when optically reading a document and performs correction related to the optical reading, the reference body and the optical system are both configured to be movable; 2. An image reading apparatus characterized in that, when reading the reference body, the reference body and the optical system move toward each other to read the reference body. 2. The image reading device according to claim 1, wherein the reference body and the optical system are in close contact with each other when reading the reference body. [Claim 3] Claim 1, wherein the reference body also serves as a document guide.
Or the image reading device according to 2. 4. A light source for illuminating a document; a lens for forming an image of reflected light from the document illuminated by the light source;
It has an optical system that is integrally configured with an image sensor that reads the original image formed by the lens, and when reading the original optically, the optical system is caused by friction with the roller for conveying the original. In an image reading device that reads a reference body by swinging it and performs correction related to optical reading, there is provided a means for applying a moment for swinging assistance to the swinging direction of the optical system when reading the reference body. An image reading device comprising: 5. The optical system according to claim 4, wherein a point of application of a force that presses the optical system against the roller is provided at a portion that does not change with respect to the direction of pressure contact between the roller and the optical system when the optical system swings. Image reading device. 6. An optical system comprising: a light source for illuminating a document; a lens for forming an image of reflected light from the document illuminated by the light source; and an image sensor for reading the document imaged by the lens. In an image reading device that reads a reference body by moving the optical system or reference body when optically reading a document, and performs correction related to the optical reading, An image reading apparatus characterized in that a part of the reference body is permanently provided within a reading range and outside the original reading area, and the reference body is read even when reading the original.