JP2855018B2 - Image scanner - 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 scanner, and more particularly, to a focus adjusting mechanism of an image scanner.

2. Description of the Related Art In recent years, image scanners have tended to have a high resolution, and accordingly, there has been a demand for the accuracy of image formation on a linear CCD sensor.

[0003]

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

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

In the carrier 3, a fluorescent light 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.

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

The carrier 3 is guided by a guide shaft 13 via a belt 12 by a motor 11 to be driven by an arrow 14.
, And scans the original 15 on the platen glass 2.

Further, the total width w of the document 15, as shown in FIG. 7, is imaged onto the entire length l ₁ of the CCD sensor 8.

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

Conventionally, the CCD sensor 8 is
The mounting surface 2 of the carrier body 20 that has been precisely machined
1 was directly screwed and attached with screws 22 and 23.

[0011]

With the high resolution,
Increases the number of bits of the CCD sensor, the length of the CCD sensor 8 is increased from l ₁ to l _2, also the lens 7 is that large numerical aperture is used.

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

As the numerical aperture of the lens increases, the depth of focus of the lens decreases to several tens of μm.

As a result, there is a possibility that defocus may occur particularly in the vicinity of both ends of the CCD sensor.

Accordingly, an object of the present invention is to provide an image scanner capable of adjusting the position of a linear CCD sensor.

[0016]

According to a first aspect of the present invention, a lens for reducing an image of a document and forming an image on the carrier body and a linear CCD sensor for reading an image formed by the lens are provided. in the image scanner provided, the retaining bracket in which the CCD sensor is mounted, together with the pin by supporting swingably about an axis orthogonal to the optical axis of the longitudinal axis and the lens of the CCD sensor, a shaft Turn the holding bracket to one side
Providing a spring member for urging and providing an adjusting screw on the other side,
Turn the adjusting screw in the screwing and loosening directions.
The position of the holding bracket is
It is configured to adjust in the direction of swinging .

The invention according to claim 2 is the invention according to claim 1.
The lens is supported on the carrier main body so as to be displaceable in the optical axis direction of the lens, and the lens is mounted on both sides of the optical axis direction by a leaf spring and an adjusting screw both attached to the carrier main body. It is a configuration that holds down.

[0018]

The printed board holding bracket according to claim 1 is swingably supported, and the bracket is held on one side with the shaft interposed therebetween.
A spring member that urges the unit to rotate is provided, and an adjustment screw is
The configuration provided acts to enable fine adjustment of the tilt of the CCD sensor.

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 acts so that fine adjustment in the optical axis direction of the lens can be performed simply by turning the adjusting screw.

[0020]

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

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

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

The printed board 9 is mounted on the bracket 30
Are fixed to the left and right pillar portions 30a and 30b of the
a and 30b.

The bracket 30 has a pin 30e fitted in the hole 33 of the carrier body 32, a pin 30f fitted in the hole 34, and a linear C-shape with the optical axis 35 (X-axis) of the lens 7A.
The CD sensor 31 is swingably supported in 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 face 32a of the carrier body 32,
A U-shaped leaf spring 40 is attached to a position where the column 30a faces, and presses against the column 30a.

On the column 30b opposite to the column 30a, a female screw 30b- ₁ is formed, and an adjusting screw 41 as an adjusting mechanism is screwed. The tip of the adjusting screw 41 is pressed against the rear end face 32 a 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.
2a.

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

Conversely, when the adjusting screw 41 is turned in the loosening direction, the bracket 30 is turned in the direction of arrow 38 by the spring force of the leaf spring 40.

The CCD sensor 31 rotates integrally with the bracket 30, and fine adjustment of the tilt, which is an error about the Z axis with respect to the YZ plane, is performed.

As shown in FIG. 2, the axis 37 is
It is set so as to pass through the center 31a of the D sensor 31, and at the time of the above fine adjustment, the CCD sensor 31 rotates around the center. That is, the optical axis 3 at the center of the CCD sensor 31
The positions in the five directions do not change. For this reason, it is not necessary to re-adjust the focal length due to the above-described tilt adjustment, and the adjustment is easy.

The lens 7A includes a leaf spring 51.
And the adjustment screw 52 are pressed on both sides, and fine adjustment is made in the optical axis 35 (X-axis) direction by appropriately turning the adjustment screw 52.

As described above, by adjusting, CC
The image of the original 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, fine adjustment of the tilt of the CCD line sensor can be performed, thereby realizing an image scanner having a high resolution. According to the invention of claim 2, fine adjustment of the position of the lens can be easily performed.

[Brief description of the drawings]

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

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

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

FIG. 4 is a rear view of the mechanism of FIG. 1;

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

FIG. 6 is a plan view of the image scanner of FIG. 5;

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 bracket 30a, 30b Left and right pillars 30b- ₁ Female thread 30c, 30d Upper and lower beam parts 30e, 30f Pin 31 Linear CCD sensor 31a Center 32 Carrier body 32a Rear end face 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 Adjusting screw

Claims (2)

(57) [Claims] 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 an image formed by the lens.
In the image scanner provided with (1), the holding bracket (3) to which the CCD sensor is attached is provided.
0) is swingably supported by pins (30e, 30f ) about an axis (37) orthogonal to the longitudinal axis (36) of the CCD sensor and the optical axis (35) of the lens, and the axis ( 37) and the holding bracket on one side
A spring member (40) for rotating and biasing the (30) is provided.
Side, an adjusting screw (41) is provided.
By turning in the direction of insertion and release,
The position of the holding bracket with respect to the shaft (37).
An image scanner characterized in that it is configured to adjust in a swinging direction . 2. The lens (7A) is supported on the carrier body (32) so as to be displaceable in the optical axis direction of the lens, and the lens (7A) is held from both sides in the optical axis (35) direction. both image scanner according to claim 1, wherein you, characterized in that a structure in which pressing the leaf spring is attached to the carrier body (51) and adjusting screw (52).