JPH05191570A - Image scanner - Google Patents

Abstract

PURPOSE:To attain the fine adjustment of tilting and shifting by constituting a holding bracket so as to be shaken, and adjusting it in the shaking direction. CONSTITUTION:At the time of turning an adjustment screw 41 in a screwing direction, a bracket 30 is turned in an arrow 39 direction while a plate spring 40 is loaded. At the time of loosing the screw 41 in the opposite direction, the bracket 30 is rotated in an arrow direction 38 by the spring force of the spring 40. A CCD sensor 31 is rotated integrally with the bracket 30, and the influence being the error of a Z shaft rotation against an Y-Z face can be finely adjusted. A shaft 37 is set so as to pass the center 31a of the sensor 31, and at the time of the fine adjustment, the sensor 31 is rotated with the shaft 37 as a center. That is, the position of the central optical axis 35 direction of the sensor 31 is not changed. Thus, it is not necessary to adjust again a focusing distance, and the adjustment can be easily attained by adjusting the tilting and shifting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image scanner, and more particularly to a focus adjusting mechanism for an image scanner.

In recent years, image scanners have tended to have a high resolution, and along with this, the accuracy of image formation on a linear CCD sensor is required.

[0003]

2. Description of the Related Art For convenience of description, first, a schematic configuration of an image scanner 1 will be described with reference to FIGS.

Reference numeral 2 is a platen glass, 3 is a carrier, and 4 is a control printed board.

A fluorescent board 5, a plurality of mirrors 6, a lens 7 and a printed board 9 on which a linear CCD sensor 8 is mounted are incorporated in the carrier 3.

The printed board 9 in the carrier 3 and the control printed board 4 are connected by a flexible cable 10.

Further, the carrier 3 is guided by the motor 11 via the belt 12 to the guide shaft 13 so that the arrow 14
The document 15 on the platen glass 2 is scanned.

Further, the entire width w of the original 15 is imaged on the entire length l ₁ of the CCD sensor 8 as shown in FIG.

Next, a conventional structure will be described with reference to FIG.

Conventionally, the CCD sensor 8 is the printed board 9
The mounting surface 2 of the carrier body 20 which is processed with high precision
It was attached to the No. 1 directly by screws 22 and 23.

[0011]

[Problems to be Solved by the Invention] With high resolution,
The number of bits of the CCD sensor increases, the length of the CCD sensor 8 increases from l ₁ to l ₂ , and the lens 7 having a large numerical aperture is used.

As the length of the CCD sensor increases, the CCD
The amount of tilt δ (see FIG. 7) due to sensor mounting error increases.

When the numerical aperture of the lens increases, the depth of focus of the lens becomes as shallow as several tens of μm.

As a result, there is a possibility that defocus will occur especially near the both ends of the CCD sensor.

Therefore, an object of the present invention is to provide an image scanner in which the position of the linear CCD sensor can be adjusted.

[0016]

According to a first aspect of the present invention, there is provided on a carrier body, a lens for reducing and forming an image of an original, and a linear CCD sensor for reading the image formed by the lens. In the provided image scanner, the holding bracket to which the CCD sensor is attached is swingably supported about an axis orthogonal to the longitudinal axis of the CCD sensor and the optical axis of the lens, and the position of the holding bracket. Is provided with an adjusting mechanism for adjusting in a swinging direction with respect to the shaft.

According to a second aspect of the present invention, there is provided an image scanner in which a carrier body is provided with a lens for reducing and forming an image of a document and a linear CCD sensor for reading the image formed by the lens. , The lens is supported by the carrier body so as to be displaceable in the optical axis direction of the lens, and the lens is pressed from both sides in the optical axis direction by a leaf spring and an adjusting screw attached to the carrier body together. It has a different configuration.

[0018]

The structure in which the printed board holding bracket is swingably supported and the structure for adjusting the swing direction are provided so that the tilt of the CCD sensor can be finely adjusted.

The structure in which the lens is held down by the leaf spring and the adjusting screw according to the second aspect of the invention functions so that the lens can be finely adjusted in the optical axis direction simply by rotating the adjusting screw.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a main part of a high resolution image scanner according to an embodiment of the present invention will be described with reference to FIGS.

Reference numeral 30 is a printed board holding bracket,
It has a substantially rectangular frame shape composed of left and right column portions 30a, 30b and upper and lower beam portions 30c, 30d connecting between the column portions 30a, 30b, and a pin 30 is provided at the center of the beam portions 30c, 30d.
e and 30f are planted.

The linear CCD sensor 31 has a length l ₂
Is as long as about 35 mm, and is mounted on the printed board 9.

The printed board 9 is attached to the bracket 30.
Fixed to the left and right pillars 30a and 30b of the pillar 30
It is attached across a and 30b.

In the bracket 30, the pin 30e is fitted in the hole 33 of the carrier main body 32, and the pin 30f is fitted in the hole 34, so that the optical axis 35 (X axis) of the lens 7A and the line C can be formed.
The CD sensor 31 is swingably supported in the directions of arrows 38 and 39 with respect to an axis 37 (Z axis) orthogonal to the longitudinal axis 36 (Y axis).

Of the rear end surface 32a of the carrier body 32,
A U-shaped leaf spring 40 is attached to a portion facing the pillar portion 30a and is pressed against the pillar portion 30a.

A female screw 30b- ₁ is formed on the column portion 30b on the side opposite to the column portion 30a, and an adjusting screw 41 as an adjusting mechanism is screwed therein. The tip of the adjusting screw 41 is pressed against the rear end surface 32a of the carrier body 32.

The bracket 30 is urged to rotate in the direction of arrow 38 by a leaf spring 40 in FIG.
It is pressed against 2a.

When the adjusting screw 41 is turned in the screwing direction, the bracket 30 is rotated in the arrow 39 direction while bending the plate spring 40.

On the contrary, when the adjusting screw 41 is turned in the loosening direction, the bracket 30 is rotated in the direction of the arrow 38 by the spring force of the plate spring 40.

The CCD sensor 31 rotates integrally with the bracket 30, and the tilt which is an error around the Z axis with respect to the YZ plane is finely adjusted.

As shown in FIG. 2, the shaft 37 has a CC
It is set so as to pass through the center 31a of the D sensor 31, and during the above fine adjustment, the CCD sensor 31 rotates about the center thereof. That is, the optical axis 3 at the center of the CCD sensor 31
The position in the five directions does not change. For this reason, it is not necessary to readjust the focal length by performing the above-mentioned tilt adjustment, and the adjustment is easy.

For the lens 7A, the leaf spring 51
Both sides are pressed by the adjusting screw 52 and the adjusting screw 52, and fine adjustment is performed in the optical axis 35 (X axis) direction by appropriately turning the adjusting screw 52.

By adjusting as described above, CC
The image of the document is in focus over the entire length of the D sensor 31, and an image scanner having high resolution can be realized.

[0034]

As described above, according to the first aspect of the present invention, the tilt of the CCD line sensor can be finely adjusted, whereby an image scanner having a high resolution can be realized. According to the invention of claim 2, fine adjustment of the position of the lens can be easily performed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a main part of an embodiment of an image scanner of the present invention.

2 is a plan view of the mechanism of FIG. 1. FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a rear view of the mechanism of FIG.

FIG. 5 is a front view showing the configuration of a general image scanner.

FIG. 6 is a plan view of the image scanner of FIG.

FIG. 7 is a diagram for explaining image formation of a document on a CCD sensor.

FIG. 8 is a diagram showing a conventional example.

[Explanation of symbols]

7A lens 9 printed board 30 printed board holding brackets 30a, 30b left and right column parts 30b- ₁ female screws 30c, 30d upper and lower beam parts 30e, 30f pin 31 linear CCD sensor 31a center 32 carrier body 32a rear end surface 33, 34 Hole 35 Optical axis (X axis) 36 Longitudinal axis of CCD sensor (Y axis) 37 Swing center axis (Z axis) 40,51 Leaf spring 41,52 Adjustment screw

Claims (2)

[Claims] 1. A lens (7A) for reducing and forming an image of an original on a carrier body (32), and a linear CCD sensor (3) for reading the image formed by the lens.
1) and an image scanner provided with a holding bracket (3
0) is swingably supported about an axis (37) orthogonal to the longitudinal axis (36) of the CCD sensor and the optical axis (35) of the lens, and the position of the holding bracket is set to the axis (37). ) Is provided with an adjusting mechanism (41) for adjusting in a swinging direction. 2. A lens (7A) for reducing and forming an image of an original on a carrier body (32), and a linear CCD sensor (3) for reading the image formed by the lens.
1) is provided, the lens (7A) is supported by the carrier body (32) so as to be displaceable in the optical axis direction of the lens, and the lens (7A) is supported by its optical axis (35). ) An image scanner characterized in that it is pressed from both sides in the direction of direction by a leaf spring (51) and an adjusting screw (52) attached to the carrier body.