JPH11266345A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the image reader where image flurring in a read image is prevented. SOLUTION: An upper cover 13 positions a position in a main scanning direction of a guide rail 6 by using guide rail insert sections 13c, 13d which are processed to position the guide rail 6 in the main scanning direction to the upper cover 13 so as to position the guide rail 6 in the main scanning direction thereby deciding the parallelism and the squareness between edges 13a, 13b of the upper cover 13 and the guide rail 6 with high accuracy.

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 which is provided in an apparatus such as an image scanner and a copying machine and reads an original by a reading sensor.

[0002]

2. Description of the Related Art In a copier, an image scanner, and the like, an image reading apparatus for reading an image by scanning an original or a recording sheet set on a platen glass disposed on an upper surface of the apparatus by a scanning optical system has been widely used. I have.

In such an image reading apparatus, a document table is generally provided on the upper surface of an upper cover 51 which is arranged so as to cover almost the entire apparatus as shown in FIG. A platen glass 52 is provided in the opening, and a document is set on the platen glass.

The standard for placing the read original is such that the original is placed by abutting against the edges 51-1 and 51-2 of the opening of the entire cover in accordance with the index described in the opening of the upper cover 51. In general, the standard is used.

The scanning optical system reads a document placed on a platen glass while scanning a guide rail with a driving force from a driving source via a driving source transmitting device such as a gear, a belt, or a wire.

[0006] The guide rail is provided in the main body frame 54.
The upper cover 51 is positioned and fixed to the apparatus body frame 54 directly with screws 53 or the like.

[0007]

However, in the case described above, the guide rail and the upper cover 51 are not directly positioned, but are separately mounted on the apparatus body frame 54 which is a base of the apparatus. And the accuracy of the parallelism and the squareness of the document abutting opening provided in the upper cover 51 are deteriorated.

When an image reading device reads an image abutting the opening of the upper cover, if the positional relationship between the rail for guiding the scanning optical system and the opening of the upper cover is not accurate, the read image may be oblique. Become.

This means that if the upper cover abuts against the guide rail at an angle, the document placed following the abutment also becomes oblique with respect to the guide rail. This is because the scanning optical system moves on the guide rail in the sub-scanning direction, so that the positional relationship between the scanning optical system and the document is shifted.

That is, even though the original is properly abutted against the abutment reference, the read image becomes skewed and an image shift occurs, which is a serious problem.

The present invention has been made in consideration of the above problems, and has as its object to provide an image reading apparatus that prevents image deviation of a read image.

[0012]

According to the present invention, there is provided an image forming apparatus comprising: an upper cover having an original table provided with a light transmitting member for mounting an original; An image reading apparatus comprising: a scanning unit that reads a document via an optical member, wherein the upper cover and the guide rail are directly positioned with respect to each other.

Accordingly, the positional relationship can be accurately obtained without the need for other components, and when a document is read with a simple configuration, the read image does not become skewed and a high-quality image that prevents image deviation of the read image is obtained. Image reading becomes possible.

It is preferable that a guide rail insertion portion for positioning the guide rail and a document abutting portion for positioning a document are provided integrally with the upper cover.

Accordingly, there is no displacement between the guide rail insertion portion and the document abutment portion, the upper cover, the guide rail and the document can be positioned relative to each other, and the image displacement of the read image can be prevented.

It is preferable that the guide rail is fixed by attaching the upper cover to the apparatus main body.

Thus, since the upper cover and the guide rail are directly positioned with respect to each other, when a document is read with a simple configuration, the read image does not become skewed, and image deviation of the read image can be prevented.

Preferably, the guide rail is fixed to the apparatus main body, and the upper cover is combined with the guide rail.

Thus, since the upper cover and the guide rail are directly positioned with respect to each other, when the document is read with a simple configuration, the read image does not become skewed, and the image shift of the read image can be prevented.

It is preferable that the upper cover and the guide rail are directly fitted to each other.

As a result, since the upper cover and the guide rail are directly positioned with respect to each other, when the original is read with a simple configuration, the read image does not become skewed, and the read image can be prevented from being misaligned.

[0022]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) The configuration of the first embodiment will be described with reference to FIGS. 1 is a front view of the present embodiment, FIG. 2 is a top view of the present embodiment, and FIG. 3 is a right side view of the present embodiment. In the present embodiment, the present invention is applied to an image scanner as an image reading device that reads a document image into a computer or the like.

A platen glass 1 as a light-transmitting member for reading an image by placing a document thereon is provided on a platen at the upper part of the main body of the image scanner. A line sensor 2 for reading the image is arranged.

The line sensor 2 is an LED for illuminating a document.
And a selfoc lens array that forms an image of the reflected image of the document by the illumination of the LED, and an optical sensor element that photoelectrically converts the image of the image on the document by the selfoc lens array. Things.

The line sensor 2 is fixed to a sensor holding frame 3. The sensor holding frame 3 is rotatably held by the movable holding frame 4. This rotation mechanism is used for the sensor holding frame 3
The rotation shafts 4a and 4b provided at both ends of the movable holding frame 4 are fitted into rotation holes provided at both ends in the longitudinal direction of the movable holding frame 4 so as to be rotatable. On the lower surface of the movable holding frame 4, a main body base 5 is provided.
Sliding part 4 guided by guide rail 6 fixed to
c, 4d.

The holding frame 4 has torsion coil springs 7a, 7
b, and the torsion coil springs 7a, 7b
Urges the sensor holding frame 3 against the moving holding frame 4 in the direction of the platen glass 1.

Here, the line sensor 2, the sensor holding frame 3
The moving and holding frame 4 is a scanning unit.

The line sensor 2 has two projections 2a, 2
b, and the projections 2 a and 2 b
, The distance between the line sensor 2 and the platen glass 1 is kept constant.

A compression coil spring 8 is provided between the rotation hole 3b of the sensor holding frame 3 and the rotation shaft 4b of the movable holding frame 4.
Are provided to urge and absorb the thrust play of the rotation axis of the sensor holding frame 3 and the moving holding frame 4.

In order to drive the image reading section guided in this way for scanning, in the present embodiment, a drive motor 9 is provided on the main body base, and a pulley 10 provided on a rotation shaft of the drive motor 9 and a main body base are provided. A belt 12 is provided between the drive motor 9 and a pulley 11 provided on the opposite side. A part of the belt 12 is fixed to a belt holding portion 4e below the movable holding frame 4. Generally, in an image scanner, a stepping motor is used as the drive motor 9.

The projections 2a, 2b of the line sensor 2
Is located in a range where the sliding portions 4c and 4d of the movable holding frame 4 are in contact with the guide rail 6 (range I in FIG. 1).

The operation of the image scanner according to this embodiment will be described below.

An original for reading an image is set on the platen glass 1 with the reading surface facing the platen glass 1.
When the power of the image scanner is turned on, the line sensor 2 is driven to the image reading start position Xs and stopped. When an image capture signal is input to the image scanner from a computer or the like (not shown), the line sensor 2 starts capturing an image of the document.

At the same time, the driving motor is driven to move the belt 12 in the sub-scanning direction, thereby moving the moving holding frame 4, the sensor holding frame 3, and the line sensor 2 integrally in the sub-scanning direction. Drive. The line sensor 2 is urged against the platen glass 1 by the torsion coil springs 7a and 7b, and the projections 2a and 2b of the line sensor 2 abut against the platen glass 1. Therefore, the distance between the line sensor 2 and the platen glass 1 is kept constant. The original is scanned while keeping the original.

Thus, the line sensor 2 can read the image on the document surface with high image quality while always maintaining a good image forming state. At the same time, the moving holding frame 4 is urged toward the guide rail 6 by the reaction force of the urging force. With this urging force, the planes 4p1 and 4p2 of the movable holding frame 4 reliably position the movable holding frame on the guide rail 6 and are guided without play, so that the sensor scans while keeping the rail perpendicular to the rail.

In general, the reading operation of the image scanner is controlled by a computer, and depending on the processing conditions of the computer itself, the scanning operation may be temporarily interrupted during reading and then resumed. If there is play in the guide portion due to the interruption or restart of the scanning operation, an image shift is likely to occur in the joint image. However, in the present embodiment, since there is no play, the line sensor 2 moves in the sub-scanning direction. Since there is no tilt, no image shift or the like occurs at all.

In this way, the line sensor 2 is driven to the image capturing end position Xe while capturing the image,
The image of the entire original is imported to the computer. When the image reading operation is completed, the drive motor 9 rotates in the reverse direction and returns the line sensor 2 to the image reading start position Xs.

Next, the abutment of the guide rail 6 and the original according to the present invention will be described with reference to FIGS.

In this embodiment, the original is used as a reference for placing the original by abutting the edges 13a and 13b of the opening of the original plate provided on the upper surface of the upper cover 13 as original abutting portions. The platen glass 1 is arranged in this opening.

When an image scanner reads an image striking the edges 13a and 13b of the upper cover 13, the positional relationship between the guide rail 6 on which the line sensor 2 moves and the edges 13a and 13b of the upper cover 13 is not accurately determined. And the read image becomes oblique.

This corresponds to the upper cover 13 with respect to the guide rail 6.
If the edges 13a and 13b are inclined at an angle, the original placed following the collision is also inclined with respect to the guide rail 6, and the line sensor 2 is positioned on the guide rail 6. Is moved in the sub-scanning direction, so that the positional relationship between the line sensor 2 and the document is shifted.

That is, the read image obtained by properly abutting the original on the abutment reference becomes oblique, which is a serious problem.

In order to solve this problem, in the present embodiment, as shown by 13c and 13d, the guide rail 6 is formed on the upper cover 13 by a guide rail insertion portion machined so as to position the guide rail 6 in the main scanning direction. The position in the main scanning direction is determined by the upper cover 13.

As described above, by positioning the guide rail 6 in the main scanning direction by the upper cover 13, the parallelism and the perpendicularity between the guide rail 6 and the edges 13a and 13b of the upper cover 13 are determined with high accuracy. This is because the guide rail insertion portions 13c and 13d for positioning the guide rail 6 and the edges 13a and 13b which position the guide rail 6 on the upper cover 13 which is the same component are arranged, so that the accumulation of errors is eliminated because no other components are interposed. Therefore, if the accuracy of the required portion of the upper cover is obtained, the positional accuracy of the guide rail 6 and the edges 13a and 13b can be directly obtained with high accuracy.

In this embodiment, the line sensor 2 slides on the guide rail 6 by the movable holding frame 4 via the sensor holding frame 3 while abutting on the platen glass 1 as described above. The vertical position accuracy between the guide rail 6 and the platen glass 1 is important. Therefore, as shown in FIGS. 4, 5, and 6, the glass receiving portion 5a and the hole 5-1 are arranged on the main body base 5, which is the same part, and the dimensions between the brackets are set to the required accuracy, so that the guide rail 6 and the platen glass are formed. 1 makes it possible to directly improve the positional accuracy.

In this embodiment, a groove 6-1 is provided near the end of the guide rail 6. By combining the groove 6-1 with the main body base 5, the thrust direction of the guide rail 6 is restricted so that the guide rail 6 does not fall off the main body base 5.

On the other hand, the guide rail 6 provided on the main body base 5
The hole 5-1 for regulating the vertical direction is shown in FIG. 6 (A-A in FIG. 5).
(A cross-sectional view as viewed from the X direction), as shown in FIG.

Thus, at the time of assembling, the guide rail 6 can be easily incorporated into the main body base 5 even when the scanning means is already assembled on the guide rail 6. In the present embodiment, the guide rail 6 is regulated up and down, but the upper cover 1 in the main scanning direction.
Until the 3 is assembled, it is not regulated. Therefore, before the upper cover 13 is assembled, the guide rail 6 can freely move in the main scanning direction.

Therefore, as shown in FIG. 6, a proper amount of play for assembling the upper cover 13 is provided by the wall of the hole 5-1 and the projection 5-2 to make it easier to assemble the upper cover 13. Is given between.

In the above-described embodiment, an example has been described in which the guide rail 6 is vertically positioned by the main body base 5. However, as described above, the line sensor 2 is used by the torsion coil springs 7a and 7b. The guide rail 6 is constantly receiving a downward force in the vertical direction due to the reaction force that urges the platen glass 1.

Therefore, as shown in FIG. 7 (a cross-sectional view taken along the line AA in FIG. 5 and viewed from the X direction), there is no need to regulate the upper side of the guide rail 6 in the vertical direction. The effect can be obtained.

(Second Embodiment) Also in the second embodiment, the present invention is applied to an image scanner for reading a document image by connecting to a computer or the like. Since the overall configuration of the image scanner of the present embodiment is the same as that of the first embodiment, the description of the overall configuration is omitted here and the main part will be described. FIG. 8 shows a second embodiment of the present invention.

In this embodiment, as shown in FIG. 8A, a substantially circular guide rail insertion portion 21 for positioning the guide rail 6 by the fitting portion is provided on the upper cover 13, and the guide rail 6 is connected to the main body base. At the time of mounting on the guide rail 5, the guide rail 6 is mounted on the guide portion 5-3 of the apparatus main body, and is not fixed in the main scanning direction or the vertical direction.

Then, as shown in FIG.
When the guide rail 3 is mounted on the main body frame 5, the vicinity of both ends of the guide rail 6 is held and fitted in the guide rail insertion portion 21 of the upper cover to be positioned and fixed in the main scanning direction and the vertical direction. ing.

In this way, the guide rail insertion portion 21 for positioning the guide rail 6 on the upper cover 13 and the edges 13a and 13b serving as references for placing a document are arranged. Will be easier to maintain.

Further, the glass receiving portion 5a and the guide rail 6
The vertical positional relationship is maintained only by the dimensional relationship of the upper cover 13, so that the guide rail 6 and the edges 13a, 13b are only required to reduce the dimensional relationship of the upper cover 1 parts to the required accuracy.
In addition, since the positional accuracy between the guide rail 6 and the glass receiving portion 5a can be improved, the required dimensional relationship can be easily managed as compared with the first embodiment.

(Third Embodiment) Also in the third embodiment, the present invention is applied to an image scanner for reading a document image by connecting to a computer or the like. Since the overall configuration of the image scanner of the present embodiment is the same as that of the first embodiment, the description of the overall configuration is omitted here and the main part will be described. FIG. 9 shows a configuration diagram of a main part of the third embodiment of the present invention.

In this embodiment, the guide rail 6 shown in FIG. 9 as in FIGS. 6 and 7 is fixed to the main body base 5, and the guide rail insertion portion provided on the upper cover 13 for the fixed guide rail 6. 13c and 13d are fitted together near the both ends of the guide rail 6 from above the device so that the position of the upper cover 13 is determined.

This is a guide rail insertion portion 13c for positioning the guide rail 6 on the upper cover 13 which is the same component.
13d and edges 13a and 13b as document abutting portions
This is because the required image reading position accuracy can be obtained by arranging these dimensions and processing these dimensions to the required accuracy, without intervening other components and without accumulating errors.

As a result, it is possible to prevent a read image of a document properly abutted against the edges 13a and 13b serving as the document abutment reference from being skewed with a simple configuration.

In the present embodiment, since the guide rail 6 is fixed to the main body base 5, the guide rail 6 does not move when the upper cover 13 is mounted on the main body base 5. Becomes possible.

[0063]

According to the present invention, there is provided an upper cover having a document table provided with a light-transmitting member on which an original is placed, scanning means guided by a guide rail and reading the original via the light-transmitting member;
An image reading device comprising: an upper cover and a guide rail that are directly positioned with respect to each other, so that the positional relationship can be accurately obtained without requiring other parts, and when an original is read with a simple configuration, reading is performed. It is possible to perform high-quality image reading that prevents an image from becoming skewed and prevents image deviation of a read image.

Since the guide rail insertion portion for positioning the guide rail and the document abutting portion for positioning the document are integrally provided on the upper cover, a deviation may occur between the guide rail insertion portion and the document abutting portion. In addition, the upper cover, the guide rail, and the document can be positioned with respect to each other, and image deviation of the read image can be prevented.

By attaching the upper cover to the apparatus body,
By fixing the guide rails, the upper cover and the guide rails are directly positioned with respect to each other, so that when reading a document with a simple configuration, the read image does not become oblique,
Image deviation of the read image can be prevented.

Since the guide rail is fixed to the apparatus main body and the upper cover is positioned with respect to the guide rail, the upper cover and the guide rail are directly positioned with respect to each other. The image does not become skewed, and image deviation of the read image can be prevented.

Since the upper cover and the guide rail are directly engaged with each other by directly fitting the upper cover and the guide rail, the read image does not become oblique when the original is read with a simple configuration. In addition, it is possible to prevent image deviation of the read image.

[Brief description of the drawings]

FIG. 1 is a front view illustrating an image scanner according to a first embodiment.

FIG. 2 is a top view illustrating the image scanner according to the first embodiment.

FIG. 3 is a sectional view showing the image scanner according to the first embodiment.

FIG. 4 is a top view showing the upper cover according to the first embodiment.

FIG. 5 is a partially enlarged view showing the image scanner according to the first embodiment.

FIG. 6 is a configuration diagram showing the fitting of the guide rail and the guide rail insertion portion in the AA cross section from the X direction of FIG. 5 according to the first embodiment.

FIG. 7 is a configuration diagram showing the fitting of the guide rail and the guide rail insertion portion in an AA cross section from the X direction in FIG. 5 according to another example of the first embodiment.

FIG. 8 is a configuration diagram illustrating fitting of a guide rail and a guide rail insertion portion according to a second embodiment.

FIG. 9 is a configuration diagram showing fitting of a guide rail and a guide rail insertion portion similar to FIGS. 6 and 7 according to the third embodiment.

FIG. 10 is a perspective view showing an image scanner according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Platen glass 2 Line sensor 2a, 2b Projection part 3 Sensor holding frame 3a, 3b Rotating hole part 4 Moving holding frame 4a, 4b Rotating shaft 4c, 4d Sliding part 5 Main body base 5a Glass receiving part 5-1 hole 5 -2 protrusion 6 guide rail 6-1 groove 7a, 7b torsion coil spring 8 compression coil spring 9 drive motor 10, 11 pulley 12 belt 13 upper cover 13a, 13b edge 13c, 13d guide rail insertion part 1

Claims (5)

[Claims] 1. An image reading apparatus comprising: an upper cover having a document table provided with a light-transmitting member on which a document is placed; and scanning means guided by a guide rail and reading the document via the light-transmitting member. An image reading apparatus, wherein the upper cover and the guide rail are directly positioned with respect to each other. 2. A guide rail insertion portion for positioning the guide rail and a document abutting portion for positioning a document,
2. The device according to claim 1, wherein the upper cover is provided integrally.
The image reading device according to claim 1. 3. The image reading apparatus according to claim 1, wherein the guide rail is fixed by attaching the upper cover to an apparatus main body. 4. The guide rail is fixed to an apparatus body,
The image reading device according to claim 1, wherein the upper cover is combined with the guide rail. 5. The image reading apparatus according to claim 1, wherein the upper cover and the guide rail are directly fitted to each other.