JP3080434B2 - Image reading device - Google Patents

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 for reading an original by moving a sheet original.

[0002]

2. Description of the Related Art FIG. 17 shows an example of the basic structure of a conventional apparatus of this type to which the present invention belongs.
Shows a schematic diagram near the sensor unit.

[0003] That is, this apparatus uses a plurality of originals 10
Paper feed guide 102 for stacking the originals 1, a conveying roller 103 for feeding the stacked originals 101 to the separation unit,
, A separation unit including a paper feed roller 105 and a retard roller 106 for separating the original 01 into individual sheets and conveying the original to a reading roller 104 also serving as a document reading position;
A white reference plate 107 also serving as a paper guide for guiding the document 101 to the document
Roller 108 and paper discharge roller 109 for discharging paper
It is composed of

A document glass 110 and a lens 111
, A sensor unit 113 integrally formed of a sensor 112 and a light source 123 are pressed against the reading roller 104 by a spring 115, and a normal axis and a tangential direction with respect to a contact point with the reading roller 104 by a fitting shaft 114. It is positioned so that it can swing.

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

In general, in an image reading apparatus including an optical system including a light source, a lens, and a sensor, even if an original having a uniform density is read due to variations in the light source, optical characteristics of the lens, etc. As a result, even if a document having a uniform density is read, information is not obtained as a uniform density, and density unevenness occurs. For this reason, conventionally, a white reference plate 7 having a uniform density is read before reading a document, 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). I was

When a reading start signal is sent from a host computer (not shown), the reading roller 104 is first rotated in reverse to perform shading correction.
When the reading roller 104 rotates in the reverse direction, the reading roller 104
The sensor unit 113 pressed against the sensor unit swings about the fitting shaft 114 as a fulcrum due to frictional force, and
Is moved onto the white reference plate 107.

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

As a result, the original 1 which is separated one by one by the separation unit and sent to the reading position on the reading roller 104
The document 101 collides with the stopped reading roller 104, the document 101 forms a loop, and the resist at the leading end of the document 101 is aligned by the waist of the document 101.

After the shading correction coefficient is determined, the reading roller 104 rotates forward, and the sensor unit 113 pressed against the reading roller 104 swings about the fitting shaft 114 to move to the reading position on the document reading roller 104. The 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 regulated by the swing stopper 117 provided in the scanner 3 and stopped, and reading of the document 101 is started.

The reading of the document 101 is performed in synchronization with a document reading signal sent line by line from the host computer, and reflected light from the document 101 illuminated by the light source 123 is imaged on the sensor 112 by the lens 111. Then, after being converted into an electric signal by the sensor 112, it is sent to the host computer.

The document 101 from which information is sequentially read by handshaking for each line is discharged to the outside of the main body via a discharge roller 108.

[0014]

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

Further, since the original 1 is looped by abutting the original against the reading roller 4 to ensure registration of the leading end of the original, the original 1 is placed at the original reading position on the reading roller 4 before the image reading is started. After the shading correction coefficient is determined, the original 1 cannot be read while the reading position of the sensor unit 13 is moved from the white-based reading position to the original reading position on the reading roller 4. However, the original 1 is conveyed, so that the leading end of the original is missing.

In these conventional apparatuses, a pressure contact of a spring 15 for pressing the sensor unit 13 against the reading roller 4 is provided on a normal line at a contact point between the sensor unit 13 and the reading roller 4.

Therefore, when the sensor unit 13 is swung in the document conveying direction at the time of reading the document, the combined weight of the sensor unit 13 itself and the spring pressure applied to the sensor unit 13 assists the sensor unit 13 in swinging. Since it acts as a moment, it can be swung reliably even if the frictional force generated between the sensor unit 13 and the reading roller 4 is small. In order to oscillate, the frictional force generated between the sensor unit 13 and the reading roller 4 is caused by the self-weight of the sensor unit 13, the oscillating load of the sensor unit 13, the spring pressure applied to the sensor unit 13, etc. A load larger than the combined load is required, and there is a possibility that reading correction cannot be performed accurately.

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 for driving the motor increases, a large motor or a high-performance motor must be used, and there is a disadvantage that the cost increases.

Further, when the friction coefficient between the sensor unit 13 and the reading roller 4 increases, the amount of wear of the reading roller 4 increases, and the material of the reading roller 4 needs to be a special material having wear resistance. Was leading up.

Further, it is conceivable to increase the frictional force by increasing the pressure contact force between the sensor unit 13 and the reading roller 4. However, since the load when the sensor unit 13 swings increases, no effect can be expected. Even if the rocking was performed reliably, it had the same disadvantages as described above.

As another conventional example, as shown in FIG. 20, the original glass 110 is configured to move in parallel with the sensor unit 113 due to friction caused by the forward / reverse rotation of the reading roller 104. 110
A white reference 120 is provided above.

When a reading start signal is sent from a host computer (not shown), the reading roller 104 is first rotated in reverse to perform shading correction. When the reading roller 104 rotates in the reverse direction, the original glass 110 pressed against the reading roller 104 moves in parallel due to frictional force, and moves to the reading position of the sensor unit 113.
When the white reference 120 provided on the reference numeral 10 moves, the original 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 forward and the original glass 110 pressed against the reading roller 104 moves in parallel, and the white reference 120
Retreats from the reading position and starts reading the document 101.

In this case, the original glass 110 is
When 0 is retracted from the reading position, the movement is stopped by the positioning (not shown) (see FIG. 22).

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

For this reason, when the light amount of the light source 123 changes due to a change in environmental temperature or the like during the reading, or when the output value of the sensor 112 changes, the actually desired shading waveform and the shading waveform read at the time of correction are changed. There will be a mess between them. As a result, there is a problem that even when a document having a uniform density is read, the density of the document changes on the way, and the actual document cannot be faithfully read.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an image reading apparatus capable of performing shading correction more accurately.

Another object of the present invention is to reduce the size of missing data.

Still another object is to ensure the swing of the optical system with a simple configuration.

Still another object of the present invention is to make it possible to read a document image more faithfully in response to an environmental change during reading.

[0031]

According to the present invention, a light source for irradiating an original is provided.
Swing around the lens for focusing reflected light, composed of an image sensor for reading the image document image by the lens, a predetermined axis from the illuminated document with the light source
A flexible optical system , which conveys the original,
And a reading roller also serving as the reading position, the image reading apparatus which performs correction according to the optical reading is performed to read the reference body when reading the document optically, the reference body is the reading roller shaft With the central axis
Compensation related to the optical reading, pivotally supported
When the reading roller is rotated in reverse,
The optical system swings about the predetermined axis,
The quasi-body swings about the central axis of the reading roller.
With this, both the reference body and the optical system are configured to be movable, and the correction relating to the optical reading is performed.
In this case, the reference body and the optical system are moved so as to approach each other to read the reference body.

Further, when reading the reference body, the reference body and the optical system are in close contact with each other.

It is preferable that the reference member is configured to also serve as a document guide.

Further, a light source for illuminating the 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 are integrally formed. The optical system has a structured optical system, and when the document is optically read, the reference system is read by swinging the optical system by friction with a roller for transporting the document, thereby correcting the optical reading. In the image reading apparatus for performing the above, a means for applying a swing assisting moment to the swing direction at the time of reading the reference body of the optical system is provided.

Preferably, the point of application of the force for pressing the optical system against the roller is provided at a portion which does not change in the direction of pressing the roller and the optical system when the optical system swings.

Still another aspect of the present invention is a light source for illuminating an original, a lens for imaging reflected light from the original illuminated by the light source, and an image sensor for reading the original formed by the lens. An image reading apparatus having an optical system configured to read the reference body by moving the optical system or the reference body when optically reading a document, thereby performing correction related to the optical reading, A part of the reference member is permanently provided in a portion outside the effective reading range of the image sensor and outside the document reading region, and the reference member is read even when reading the document.

[0037]

In the present invention, not only the optical system for reading a document but also the reference body itself serving as a reference for shading correction can be moved, and the optical system and the reference body are brought into contact with each other even during reading correction. Accurate correction can be performed.

Further, by moving the optical system and the reference body closer to each other, the substantial movement amount 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 reading missing dimension of the document.

Further, by providing a swing assisting moment in the swing direction of the optical system at the time of correction, the optical system can be surely secured even when the friction coefficient between the optical system and the reading roller is small. Swingable.

Further, even if the pressing load of the optical system is increased,
The optical system can be reliably swung.

Further, by increasing 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 in a portion outside the reading range of the original, and the light amount of the light source during image reading is always present. By allowing the change to be measured, the correction factor is corrected sequentially.

[0042]

1 to 3 show a schematic structure near a sensor unit of an image reading apparatus according to a first embodiment of the present invention. That is, this image reading apparatus is capable of
, A feed roller 3 for feeding the stacked originals 1 to a separation unit, and a feed roller 4 for separating the originals 1 one by one and conveying them to a reading roller 4 also serving as an original reading position. A separating section constituted by a paper roller 5 and a retard roller 6; a white reference plate 7 for shading correction also serving as a paper guide for guiding the original 1 to the reading roller 4; and a discharge roller for discharging the original 1 8 and a discharge roller 9.

The sensor unit 13 integrally formed of the original glass 10, the lens 11, the sensor 12, and the light source 23 is pressed against the reading roller 4 by a spring 15, and is brought 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, a white reference plate 7 as a reference body for shading correction, which also serves as a paper guide for guiding the document 1 to the reading roller 4, is also configured to be swingable about the swing axis of the reading roller 4. , A sensor unit 13 as an optical system by a leaf spring 19 provided on a base 18.
Is pressed against.

When a read start signal is sent from a host computer (not shown), the reading roller 4 is first used to perform shading correction as in the prior art.
Is reversed, the sensor unit 13 pressed against the reading roller 4 swings around the fitting shaft 14, 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 generated between the white reference plate 7 and the original surface of the sensor unit 13. Since the sensor unit 13 is rotated by the force, the sensor unit 13 and the white reference plate 7 are always in contact with each other.

Further, since the white reference plate 7 also rotates with the swing of the sensor unit 13, the opening angle of the paper guide is widened, so that the original 1 can be easily guided to the reading roller 4, and the registration of the leading end of the original is performed. The space for the loop to be made is also large.

After the shading correction coefficient is determined, the sensor unit 13 to which the reading roller 4 is normally rotated and pressed against is read.
The white reference plate 7 moves to the original reading position on the reading roller 4 about the fitting shaft 14, but is pressed by the sensor unit 13, rotates about the reading roller 4 axis, and moves from the original reading position of the sensor unit 13. fall back.

Further, the relative movement of the reading position of the sensor unit 13 and the white reference plate 7 so as to approach each other at the time of shading correction makes the movement amount of the sensor unit 13 half as compared with the conventional example. After that,
The original 1 whose information is sequentially read by handshaking line by line similarly to the conventional example is discharged to the outside of the main body via the discharge roller 8. [Other Embodiments] FIGS. 3 and 4 show a schematic configuration near a sensor unit according to a second embodiment of the present invention. The basic configuration and basic operation of the present invention are the same as in the conventional embodiment.

In this embodiment, the original 1 is
The white reference plate 7 for shading correction, which also serves as a paper guide for guiding the paper, is attached to the sensor unit 13 so as to be slidable back and forth with respect to the document transport direction, and in the document reading position direction of the sensor unit 13. It is pulled by the coil spring 24.

When a reading start signal is sent from a host computer (not shown), the reading roller 4 is first rotated in the reverse direction and the sensor unit 13 pressed against the reading roller 4 is fitted in order to perform shading correction as in the conventional example. The reading position of the sensor unit 13 moves on 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 is regulated by the boss 22 provided on the main body side plate (not shown). Is the reading roller 4
Although it is configured not to be able to move to the upper document reading position, the white reference plate 7 moves to the reading position of the sensor unit 13 by the coil spring 24 provided in the sensor unit 13 as the sensor unit 13 swings.

Further, since the white reference plate 7 also swings with the swing of the sensor unit 13, the opening angle of the paper guide is widened so that the original 1 can be easily guided to the reading roller 4 and the resist is formed at the leading end of the original. Also, the space for the loop to be used is increased.

After the shading correction coefficient is determined, the sensor unit 13 to which the reading roller 4 is normally rotated and pressed against is read.
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 document reading position on the reading roller 4, the swing stopper B17 provided on the sensor unit 13 similarly to the reverse rotation.
The swing of the sensor unit 13 is stopped, and the reading of the document 1 is started.

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

Further, since the reading position of the sensor unit 13 and the white reference plate 7 perform relative movement so as to approach each other at the time of shading correction, the amount of movement of the sensor unit 13 is halved as compared with the conventional example.

Thereafter, as in the conventional example, the original 1 whose information is sequentially read by handshaking line by line is discharged to the outside of the main body via the discharge roller 8.

FIGS. 6 and 7 are schematic structural views showing the vicinity of the sensor unit according to the third embodiment of the present invention. In the present invention, the basic configuration and basic operation are the same as those of this type of conventional device.

In this embodiment, the pressure contact of the spring 15 for pressing 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. Let me do it. When a reading start signal is sent from a host computer (not shown), the reading roller 4 is first rotated in reverse to perform shading correction as in the conventional example, and the sensor unit 13 pressed against the reading roller 4 causes the fitting shaft 14 to move. Swing to the fulcrum,
The reading position of the sensor unit 13 moves on the white reference.

At this time, the spring 1 for pressing the sensor unit 13
5 is moved to the paper discharge roller 8 side, so that the sensor unit 13
The moment acts to assist the swing of the sensor unit 13, and the sensor unit 13 can be reliably swung even if the frictional force between the sensor unit 13 and the reading roller 4 is small.

When the coefficient of friction of the reading roller 4 is small, the sensor unit 1 is used to increase the document conveying force.
Even if the pressing force of the spring 15 for the third pressing is increased, the moment for assisting the swing of the sensor unit 13 is increased in proportion to the increase of the pressing force, so that the sensor unit 13 can swing reliably.

FIG. 8 is a schematic structural view showing the vicinity of the sensor unit 13 according to a fourth embodiment of the present invention. In the present invention, the basic configuration and basic operation are the same as those of this type of conventional device.

In the present embodiment, the pressure contact of the spring 15 for pressing the sensor unit 13 against the reading roller 4 is the same as in the third embodiment.
Is moved in the direction of the discharge roller 8 with respect to the normal at the contact point.

Further, in this embodiment, the pressure contact of the spring 15 for pressing the sensor unit 13 is provided at a portion where there is no change in the pressing direction of the spring 15 when the sensor unit 13 swings.

For this reason, when the sensor unit 13 swings, the pressing force of the spring 15 does not fluctuate both when reading the original document and when reading the shading, and the weight of the sensor unit 13 which has become a load at the time of swinging, Since there is no change in the spring load applied to the inner sensor unit 13 such as the sliding load of the sensor unit 13 and the spring pressure applied to the sensor unit 13, the swing load can be reduced.

FIGS. 9 and 10 are schematic structural views showing the vicinity of the sensor unit 13 according to the fifth embodiment of the present invention.
In the present invention, the basic configuration and basic operation are the same as those of this type of conventional device.

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 swing direction when reading the white reference. The normal direction at the contact point between the sensor unit 13 and the reading roller 4 and the pressing direction of the spring 15 for pressing the sensor unit 13 against the reading roller 4 are the same as in the conventional example.

When a reading start signal is sent from a host computer (not shown), the reading roller 4 rotates in reverse to perform shading correction as in the conventional example, and the reading position of the sensor unit 13 moves on the white reference. At this time, since the sensor unit 13 is provided with the coil spring 24 for assisting the swing of the sensor unit 13, the swing of the sensor unit 13 is assisted in the swing direction of the sensor unit 13 unlike the conventional device. Thus, the moment acts, and 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.

When the original conveying force of the reading roller 4 is small, the original conveying force may be increased.
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 and the auxiliary force is increased accordingly.
Can be reliably swung.

FIGS. 11 and 12 are schematic diagrams showing the vicinity of the white reference according to the seventh embodiment of the present invention. The basic configuration and basic operation of this embodiment are the same as those of the conventional embodiment.

In the present embodiment, the white reference 15 on the upper surface of the original glass 9 which can be moved in parallel in the original reading direction, as in the conventional apparatus, has an end outside the reading range of the original 1 and a sensor. 11 It is bent in an L-shape at the portion 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 original reading line is read by the sensor 11, and shading correction is performed so that the output becomes 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 the white reference provided on the original glass 9 to the reading position of the sensor unit 13. 15 moves to determine a shading correction coefficient (see FIG. 1). After the shading correction coefficient is determined, the reading roller 4 rotates forward and the original glass 9 moves in parallel, and the white reference 15 retreats from the reading position to start reading the original 1 (see FIG. 2).

At this time, since a part of the white reference 15 outside the reading range of the original 1 is within the effective reading range of the sensor 11, the change in the light amount of the light source 12 can be always detected. , The shading correction coefficient determined before the start of document reading is constantly corrected.

The original 1 whose information is sequentially read by handshaking for each line is discharged to the outside of the main body via the discharge rollers 7.

FIGS. 13 and 14 are schematic views showing the vicinity of the white reference according to the eighth embodiment of the present invention. In this embodiment, the basic configuration and basic operation are the same as in the first embodiment.

In the present 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 the same as that of the original. It is provided on the reading roller side of the original glass 9 which is configured to be able to move in parallel in the reading direction.

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 the white reference 15 provided on the original glass 9 moves to the reading position of the sensor unit 13. A shading correction coefficient is determined (see FIG. 13). At this time, since the white reference 15 is provided at the document reading position, that is, at the focus surface of the lens 10, accurate shading correction can be performed as compared with the above example. After the shading correction coefficient is determined, the reading roller 4 rotates forward, the document glass 9 moves in parallel, the white reference 15 retreats from the reading position, and reading of the document 1 starts (see FIG. 14). At this time, the white reference 15 outside the reading range of the original 1
Is located in the effective reading range of the sensor 11 so that a change in the light amount of the light source 12 can always be detected, and the shading correction coefficient determined before the start of the document reading is constantly corrected according to the change in the light amount. Is configured. The length of the reading roller 4 is set to be shorter than the position of the white reference 15 at the time of reading, and the white reference 15 does not deteriorate due to friction with the reading roller 4 when reading the original 1. The document 1 whose information is sequentially read by handshaking for each line is discharged to the outside of the main body via the discharge roller 7.

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

In this embodiment, the white reference 15 for shading correction is provided on a paper guide 16 for guiding the original 1 to the reading roller 4. A sensor unit 13 in which the original glass 9, the lens 10, the sensor 11, and the light source 12 are integrally formed is pressed against the reading roller 4 by a spring 14. On the other hand, it is positioned so as to be swingable in a normal direction and a tangential direction.

For this reason, when a reading start signal is sent from a host computer (not shown), the reading roller 4 is first reversed to perform shading correction. When the reading roller 4 rotates in the reverse direction, the sensor unit 13 pressed against the reading roller 4 swings around the fitting shaft 17 due to frictional force, and the reading position of the sensor unit 13 moves on the white reference 15. The sensor unit 13 swings to the position of the white reference 15, and the sensor unit 13 is stopped by the swing stopper A 18 provided on the sensor unit 13.

After the shading correction coefficient is determined, the reading roller 4 rotates forward and the sensor unit 13 pressed against the reading roller 4 swings around the fitting shaft 17 to move the sensor to the reading position on the original reading roller 4. The unit 13 moves.

When the sensor unit 13 reaches the reading position on the document reading roller 4, the swing is restricted by the swing stopper A 19 provided on the sensor unit 13 and stopped.
Start reading.

At this time, the end of the paper guide 16 extends to the original reading position outside the reading range of the original 1 and including the part of the white reference 15 and within the effective reading range of the sensor 11, and the light source is constantly illuminated. Twelve changes in light quantity can be detected.

For this reason, it is configured electrically so that the shading correction coefficient determined before the start of document reading is constantly corrected in accordance with the change in the amount of light. The document 1 whose information is sequentially read by handshaking for each line is discharged to the outside of the main body via the discharge roller 7.

[0085]

According to the present invention having the above construction, by moving both the optical system and the reference member, it becomes possible to bring the optical system and the reference member into close contact at the time of correction for reading. , Accurate correction becomes possible.

Further, by moving the optical system and the reference member relative to each other, the amount of movement of the optical system is reduced, and an unreadable area generated during the movement of the optical system reading position from the reference member reading position to the document reading position. The chipping of the leading edge of a document at a certain place is also reduced.

Further, when the reference body also serves as the document guide, the angle of the document guide is increased by moving the reference body, so that a space for forming a loop for registering the document is widened, and the document transportability is improved. It also has the effect of improving

Further, by setting the point of application of the spring load of the optical system such that a positive moment is applied to the swing direction at the time of reading the reference body of the optical system, even if the spring load is increased, the sensor of the sensor can be used. The swing load can be reduced.

Further, even if the coefficient of friction of the reading roller with the optical system is low, it is not necessary to increase the load of the spring pressure, so that the wear resistance of the reading roller can be improved.

Further, the method of forming the reference body for correction within the reading range of the optical system and at a portion outside the reading size of the original makes it possible to read the reference body even when reading the original. A change in the correction coefficient due to a change in the amount of light in the middle can be changed even during image reading, and an image faithful to a document having no density change in the middle of reading can be read.

Further, by reading the reference body at the original reading position of the optical system, that is, at the image forming point of the lens, more accurate correction can be performed.

[Brief description of the drawings]

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

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

FIG. 3 is an overall configuration diagram of the image reading apparatus of FIG. 1;

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

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

FIG. 6 is a schematic configuration diagram near a sensor unit of a document reading apparatus according to a third embodiment of the present invention.

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

FIG. 8 is a schematic configuration diagram near 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 near a sensor unit at the time of shading reading according to a sixth embodiment of the present invention.

FIG. 11 is a schematic view of the vicinity of a white reference when reading shading according to a 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 showing the vicinity of a white reference at the time of shading reading according to an eighth embodiment of the present invention.

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

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

FIG. 16 is a schematic view 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 apparatus.

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

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

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

FIG. 21 is a schematic view of the vicinity of a white reference when a conventional apparatus of this type is used for shading reading.

FIG. 22 is a schematic view of the vicinity of a white reference when a document is read by this type of conventional apparatus.

[Explanation of symbols]

 1 Document 4 Reading Roller 7 White Reference Plate 10 Document Glass 11 Lens 12 Image Sensor 13 Sensor Unit (Optical System) 14 Fitting Axis 15 Spring 23 Light Source 120 White Reference

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 1/04-1/207

Claims (6)

(57) [Claims] A light source for irradiating a document, a lens for imaging reflected light from the document illuminated by the light source,
An optical system , which comprises an image sensor for reading an original image formed by the lens, and which can swing about a predetermined axis; and a mechanism for conveying the original and reading the original.
An image reading apparatus that has a reading roller also serving as an arrangement, and performs reading of a reference body when optically reading a document and performs correction related to the optical reading. Swing as center axis
When the optical reading is performed freely and the correction related to the optical reading is performed, the reading is performed.
When the take-up roller rotates in the reverse direction, the optical system
Swings around a fixed axis, and the reference body
Of by swinging about a central axis, as well as configured to be movable both the reference body and the optical system, the optical according to the read correction <br/> the reference body and the optical when performing An image reading apparatus, wherein a system moves so as to approach each other to read the reference body. 2. The image reading apparatus according to claim 1, wherein, at the time of reading the reference member, the reference member and the optical system are in close contact with each other. 3. The image reading apparatus according to claim 1, wherein the reference body also functions as a document guide. 4. A light source for illuminating a document, a lens for imaging reflected light from the document illuminated by the light source, and an image sensor for reading a document image formed by the lens are integrally formed. The optical system has a constructed optical system, and when the original is optically read, the optical system is swung by friction with a roller for transporting the original, thereby reading the reference body and correcting the optical reading. A means for applying a swing assisting moment to the swing direction in reading the reference body of the optical system. 5. An apparatus according to claim 4, wherein an action point of a force for pressing said optical system against said roller is provided at a portion which does not change in a direction of pressing said roller and said optical system when said optical system swings. Image reader. 6. A light source for illuminating a document, a lens for imaging reflected light from the document illuminated by the light source,
An optical system that includes an image sensor that reads an original image formed by the lens, and reads the reference body by moving the optical system or the reference body when reading the original optically; In the image reading apparatus for performing a correction relating to a typical reading, a part of the reference body is permanently provided in a portion outside the document reading area within the effective reading range of the image sensor, and reads the reference body even when reading the document. An image reading apparatus characterized by having such a configuration.