JPH09307704A - Lighting position adjustment mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the lighting position adjustment mechanism by which the position of a slit member shaping a lighting light to be a line shape is adjusted with respect to a line sensor with a very simple configuration without producing dust. SOLUTION: An optical unit 60 in which a slit member 38 and cylindrical lenses 42a, 42b are supported integrally is mounted on a base 44, the position of the optical unit 60 is moved by adjusting cam members 72a, 72b in press contact with a side face of the optical unit 60 so as to adjust the position of the slit member 38 with respect to a CCD line sensor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reading an image by illuminating a document in a line shape and guiding the transmitted light or reflected light to a line sensor with high accuracy. The present invention relates to an illumination position adjusting mechanism set on a line sensor.

[0002]

2. Description of the Related Art FIGS. 5A and 5B show a general structure of an image reading apparatus for reading image information carried on a transparent original by a CCD line sensor. In this image reading apparatus, the illumination light L emitted from a cylindrical light emitting source 2 such as a fluorescent lamp is condensed by a first optical system 4 and then guided to a second optical system 8 through a linear slit 6. The transmissive original F is illuminated linearly by the second optical system 8. Then, the illumination light L carrying the image information from the transmissive original F is passed through the condenser lens 10 to CC.
The light is focused on the D line sensor 12. In this case, the transmissive original F is scanned by the CCD line sensor 12 in the main scanning direction (arrow Y direction), and the transmissive original F is conveyed in the sub scanning direction (arrow X direction), so that an image is displayed. Read dimensionally.

Here, the CCD line sensor 12 is shown in FIG.
As shown in FIG. 1, the light receiving unit 12 a is provided on the base 16 housed in the casing 14.
2a is a cover glass 1 fixed on the casing 14.
Protected by 8. The light receiving portion 12a is formed to be long in the main scanning direction and narrow in the sub scanning direction, and the illumination light L from the light emitting source 2 is received by the light receiving portion 1a.
It has to be guided exactly along 2a. That is, when the illumination light L is diverted from the light receiving portion 12a and applied to the base 16, the illumination light L reflected by the base 16 is reflected.
This is because a part of the incident light enters the light receiving unit 12a as flare. Therefore, in the conventional image reading device,
By displacing the slit 6 in the sub-scanning direction (direction of arrow X), adjustment is performed so that the illumination light L is accurately guided to the light receiving portion 12a.

However, in the structure of the image reading apparatus described above, when adjustment is performed by displacing the slit 6 in the sub-scanning direction (direction of arrow X), the slit 6 is held against its holding member (not shown). And sliding causes dust to be generated, and the dust is dropped onto the transmission type document F and other optical systems, which causes streaky unevenness in the read image. Will occur. On the other hand, in order to avoid such an adverse effect, the slit 6
It is conceivable that the slit 6 is held at a position considerably separated from the optical path of the illumination light L and is configured to be displaced in that state. However, since the slit 6 is usually extremely thin, 6 may be distorted, or the mechanism for avoiding such distortion may be considerably complicated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to avoid the above-mentioned inconvenience, and the slit member for shaping the illumination light into a line shape has a very simple structure without generating dust. It is an object of the present invention to provide an illumination position adjusting mechanism that can adjust the position of a line sensor.

[0006]

In order to solve the above-mentioned problems, according to the present invention, an original carrying an image through a condensing optical system after the illumination light from a light source is shaped into a line by a slit member. And the transmitted light or reflected light of the illumination light from the original is received by the long line sensor in the main scanning direction, while the original is relatively displaced in the sub-scanning direction orthogonal to the main scanning direction. So that the image is 2
An illumination position adjusting mechanism incorporated in an image reading device that reads dimensionally, wherein an optical unit including the slit member and the condensing optical system is disposed displaceably with respect to a base and provided on the base. By displacing the optical unit with respect to the base by a position adjusting member, the position of the slit member with respect to the line sensor in the sub-scanning direction is adjusted.

In this case, since the condensing optical system integrally formed is displaced along with the displacement of the slit member by the position adjusting member, it is possible to avoid the situation where dust adheres to the condensing optical system. it can.

[0008]

FIG. 1 shows a schematic configuration of an image reading apparatus to which an illumination position adjusting mechanism according to an embodiment of the present invention is applied. This image reading device basically comprises a light source unit 20, an illumination position adjusting mechanism 22, a document cassette 24 holding a transmissive document F, a condenser lens 26, and a CCD line sensor 28. The light source unit 20 includes a hollow cylindrical diffusion cavity 30, and halogen lamps 32a for supplying illumination light L to both ends of the diffusion cavity 30.
And 32b are provided. The diffusion cavity 30
Is a slit 34 extending in the main scanning direction (arrow Y direction).
And the illumination light L emitted from the slit 34 is
It is guided to the illumination position adjusting mechanism 22.

The illumination position adjusting mechanism 22 includes the cover glass 3
A slit member 38 for adjusting the width of the illumination light L incident via 6 in the sub-scanning direction (arrow X direction), a reflection mirror 40 for deflecting the emission direction of the illumination light L passing through the slit member 38, and , An optical unit 60 having two cylindrical lenses 42a and 42b for converging the illumination light L on the transmissive original F, a base 44 for supporting the optical unit 60, and the base 44 for the base 44. It is composed of a position adjusting member (described later) for adjusting the position of the optical unit 60.

The original cassette 24 disposed below the illumination position adjusting mechanism 22 includes two transparent glasses 46a and 4a.
The transparent original F is held between 6b, and is configured to be able to be transported in the sub-scanning direction (arrow X direction) by a transport mechanism (not shown).

The illumination position adjusting mechanism 22 is constructed as shown in FIGS. That is, the bracket 50 that constitutes the optical unit 60 is disposed on the upper surface of the base 44, and between the bracket 50 and the base 44, a lens holding unit that holds the cylindrical lenses 42a and 42b is provided. A bracket 52 is provided. The lens holding bracket 52 is fixed to the bracket 50 with bolts 53. In addition, on the upper portion of the bracket 50, a wall surface set upright,
A bracket 54 having a wall surface set at an inclination angle of about 45 ° with respect to the vertical direction is provided. The brackets 50 and 54 are arranged in the main scanning direction (arrow Y
Direction) is formed in a triangular prism shape. Bracket 5
Lens holding bracket 52 mounted on the bottom surface of
Is loosely fitted in the lens insertion hole 58 formed in the base 44. The cover glass 36 and the slit member 38 extending in the main scanning direction (arrow Y direction) are fixed to the wall surface of the bracket 54 which is set upright. The reflection mirror 40 is fixed to the inclined wall surface of the bracket 54.

The cover glass 36, the slit member 38, the reflecting mirror 40, and the cylindrical lenses 42a, 42.
The optical unit 60 provided with b is integrally formed, and the optical unit 60 has a unit fixing screw 62.
It is fixed to the base 44 by a and 62b. That is,
As shown in FIG. 4, the unit fixing screws 62a and 62b are provided with holes 64a and 6 formed in the lens holding bracket 52 that holds the cylindrical lenses 42a and 42b.
4b is loosely fitted and fixed to the base 44. The lens holding bracket 52 is sandwiched between the flanges 66a and 66b provided on the unit fixing screws 62a and 62b and the base 44, whereby the optical unit 60 is fixed.

On the other hand, the protrusion 6 is formed at the center of the base 44.
8 is provided, and the spring member 70 engages with the protrusion 68. Both ends of the spring member 70 are fixed to the bracket 50. Further, on the base 44, cam members 72a, 72b are provided near both ends of the spring member 70.
Are arranged. The cam members 72a and 72b are configured to be rotatable by a driver or the like, and are arranged such that the outer peripheral surfaces of the cam members 72a and 72b come into contact with the side surface portions of the bracket 50.

The image reading device to which the illumination position adjusting mechanism 22 of the present embodiment is applied is basically constructed as described above, and its operation will be described below.

The halogen lamp 32 in the light source section 20
The illumination light L emitted from a and 32b is reflected and diffused by the inner peripheral surface of the diffusion cavity 30, and then the slit 34
Is guided to the optical unit 60 that constitutes the illumination position adjusting mechanism 22.

The illumination light L guided to the optical unit 60
Is incident on the slit member 38 through the cover glass 36 to adjust the width in the sub-scanning direction (direction of arrow X), and then is reflected downward by the reflection mirror 40 to pass through the cylindrical lenses 42a and 42b. The light is focused on the transmissive document F carried by the document cassette 24. The illumination light L transmitted through the transmissive original F is further condensed by the condenser lens 26, and the CCD line sensor 2
It is led to 8. In this case, the illumination light L performs main scanning on the CCD line sensor 28 in the direction of arrow Y, while the transmissive document F is sub-scanned and conveyed in the direction of arrow X, thereby reading a two-dimensional image. Be seen.

Here, as described above, the slit member 3
CCD line sensor 28 for illumination light L shaped by 8
If the position with respect to is not adjusted, it becomes impossible to read a highly accurate image. Therefore, next, a method of adjusting the position of the slit member 38 using the illumination position adjusting mechanism 22 will be described.

In this case, the unit fixing screws 62a and 62b shown in FIG. 2 or 3 are loosened so that the optical unit 60 can move with respect to the base 44. And
The optical unit 60 is displaced in the sub-scanning direction (arrow X direction) by rotating the cam members 72a and 72b by a predetermined amount with a driver or the like. Therefore, the optical unit 6
Illumination light L that has entered 0 and passed through the slit member 38.
Are displaced in the sub-scanning direction (arrow X direction) on the CCD line sensor 28. The position of the linear illumination light L formed on the CCD line sensor 28 can be adjusted based on the output obtained by measuring the output from each photoelectric conversion unit of the CCD line sensor 28. After the position of the illumination light L is adjusted, the unit fixing screws 62a and 62b are tightened to fix the optical unit 60 to the base 44.

When the position of the slit member 38 with respect to the CCD line sensor 28 is adjusted, not only the slit member 38 is displaced relative to the cylindrical lenses 42a and 42b, but the entire optical unit 60 is displaced. Therefore, dust or the like is not generated and adheres to the cylindrical lenses 42a and 42b, and therefore, no inconvenience occurs in reading an image. Therefore, the image carried on the transmissive original F can be read with high accuracy by using the optical system adjusted as described above.

[0020]

As described above, according to the present invention, dust is not generated when adjusting the position of the slit member for shaping the illumination light into a line, and therefore, there is a problem in reading an image. Absent. Further, since the position adjusting mechanism of the slit member is extremely simple, it is possible to provide an extremely inexpensive position adjusting mechanism.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image reading apparatus to which an illumination position adjusting mechanism according to the present embodiment is applied.

FIG. 2 is a perspective configuration diagram of an illumination position adjusting mechanism.

FIG. 3 is a sectional view of an illumination position adjusting mechanism.

FIG. 4 is a plan view of an illumination position adjusting mechanism.

5A and 5B are a schematic vertical cross-sectional configuration diagram and a side view of the image reading apparatus.

FIG. 6 is a schematic sectional configuration diagram of a CCD line sensor.

[Explanation of symbols]

20 ... Light source part 22 ... Illumination position adjusting mechanism 24 ... Original cassette 26 ... Condensing lens 28 ... CCD line sensor 36 ... Cover glass 38 ... Slit member 40 ... Reflecting mirror 42a, 42b ... Cylindrical lens 44 ... Base 62a, 62b ... Unit fixing screw 68 ... Projection portion 70 ... Spring member 72a, 72
b ... Cam member

Claims (2)

[Claims] 1. An illumination light from a light source is shaped into a line by a slit member, and then is irradiated onto a document carrying an image through a condensing optical system to transmit transmitted light or reflected light of the illumination light by the document. Illumination incorporated in an image reading device that two-dimensionally reads the image by relatively displacing the document in a sub-scanning direction orthogonal to the main scanning direction while receiving light by a long line sensor in the main scanning direction. A position adjusting mechanism, wherein an optical unit including the slit member and the condensing optical system is disposed so as to be displaceable with respect to a base, and the optical unit is mounted on the base by a position adjusting member provided on the base. The illumination position adjusting mechanism is characterized in that the position of the slit member in the sub-scanning direction is adjusted with respect to the line sensor by displacing the slit member with respect to the line sensor. 2. The mechanism according to claim 1, wherein the position adjusting member includes a cam member arranged on the base and a spring member for biasing the optical unit against the cam member. An illumination position adjusting mechanism, comprising: the optical unit being displaced by rotating the cam member.