JP2004271581A - Image scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image scanner that can adjust the focusing position of a rod lens array by moving the rod lens array along an optical axis, in the image scanner which focuses light transmitted through a rod lens array having small depth of field on a CCD and obtains image data included in the light. <P>SOLUTION: Reflected light from a document medium on a platen glass 8 is guided to a line sensor 12 by a read optical system comprising a 1st reflector 13, the rod lens array 15, and a 2nd reflector 14 in a carriage 20 to obtain image data. The rod lens array 15 is held on a lid body 22 covering a base 21 of the carriage 20 and the lid body 22 is made movable to and away from the base 21 along the optical axis of the rod lens array 15. After the focus position of the rod lens array 15 is adjusted by the movement of the lid body 22, the lid body 22 is fixed to the base 21. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for acquiring an image formed on an original medium such as PPC paper, photographic paper, various types of paper, and film as image data suitable for being stored in a recording medium via a personal computer, for example. An image reading device that reads image data by making the image data contained in the reflected light of the light applied to the photoelectric conversion element incident on the photoelectric conversion element and easily adjusts the reflected light to focus on the light receiving surface of the photoelectric conversion element. The present invention relates to an image reading apparatus capable of performing the operation.
[0002]
[Prior art]
2. Description of the Related Art With the spread of personal computers in recent years, it has become convenient to store and store photographs, text documents, and other images as image data in a storage medium, print them as desired, and distribute them as data. To read this kind of image as image data, an image reading device, in particular, an image scanner is used.
[0003]
This type of image scanner includes a platen glass made of a transparent glass plate on which a document medium such as a photographic paper or a film on which an image from which image data is to be obtained is formed is placed, and the document medium placed on the platen glass Is irradiated with light, and the reflected light is captured by a photoelectric conversion element to acquire image data on an image formed on the document medium. As a typical example of the photoelectric conversion element, a CCD (charge coupled element) is well known. The acquisition of the image data is performed while the carriage is running along the platen glass. That is, the carriage is equipped with a light source for illuminating the document medium, a photoelectric conversion element for capturing image data contained in the reflected light, and a reading optical system for forming an optical path for guiding the reflected light to the photoelectric conversion element. While the carriage is running, an image on a document medium is read and scanned to obtain image data.
[0004]
As shown in FIG. 4, in the image scanner 1, a carriage 3 is accommodated in a casing 2 which is assembled in a rectangular shape with a synthetic resin or metal so as to be able to reciprocate in the direction of arrow S. One end of the carriage 3 is connected to a guide rod 4 laid over the housing 2 in a direction parallel to the arrowhead S, and a roller 4a is rotatably supported at the other end. Guides three round trips. A drive belt 5 is connected to an end connected to the guide rod 4. The drive belt 5 is wound around a pair of pulleys 6 a and 6 b rotatably supported near the ends of the guide rods 4 at the corners of the housing 2. 7 is transmitted. That is, the drive belt 5 is moved by the output rotation of the drive motor 7, and the carriage 3 connected thereto is moved. The drive motor 7 is reversibly rotatable, and the carriage 3 reciprocates according to the direction of rotation.
[0005]
A transparent platen glass 8 is placed on the upper surface of the housing 2 that houses the driving mechanism including the carriage 3, the driving motor 7, the driving belt 5, and the pulleys 6a and 6b. The bottom surface is closed by the bottom plate 9. The bottom plate 9 may be made of a transparent glass plate. For example, when the image scanner 1 is placed on a document medium placed on a desk or the like, image data relating to an image formed on the document medium is stored. The acquisition is preferable because the position of the document medium covered by the image scanner 1 can be confirmed. Generally, an original medium such as PPC paper or photographic paper on which an image is formed is placed on the platen glass 8 to acquire these image data. Further, the carriage 3 is pressed against the platen glass 8 to such an extent that the smooth movement of the carriage 3 is not hindered. Is interposed. Further, some platen glasses 8 have a sliding guide sheet or the like adhered thereon so as to smoothly slide the portion where the carriage is pressed.
[0006]
By the way, the spread of personal computers to general households poses a problem of securing a space for installing the personal computer, and furthermore, it becomes more difficult to secure a space for installation due to an increase in peripheral devices such as image scanners. For this reason, peripheral devices have been reduced in size, and image scanners have been made thinner and vertically installed when not in use, so that they can be stored in, for example, gaps between legs of a desk or the like on which a personal computer is installed.
[0007]
In order to reduce the thickness of the image scanner, it is necessary to reduce the thickness of the carriage 3, and it is required to reduce the optical path length of a reading optical system that guides the reflected light to the photoelectric conversion element. For this reason, as shown in FIG. 3, the carriage 3 has a light source 11 for illuminating the original medium on the platen glass 8 and receives light reflected by the original medium to obtain image data included in the light. And a first reflecting mirror 13 and a second reflecting mirror 14 for guiding the reflected light from the original medium to the line sensor 12, and the reflected light between the first reflecting mirror 13 and the second reflecting mirror 14. A rod lens array 15 in which a number of gradient index lenses are arranged to form an image on the line sensor 12 is mounted. The line sensor 12 is attached to the carriage 3 in a state where the line sensor 12 is incorporated in the sensor substrate 12a (for example, refer to Japanese Patent Application No. 2002-96760).
[0008]
[Patent Document 1]
Japanese Patent Application No. 2002-96760
[0009]
[Problems to be solved by the invention]
The rod lens array 15 used in the reading optical system needs to be adjusted to focus on the light receiving surface of the line sensor. The adjustment of the focal position in the conventional carriage 3 is performed by interposing a spacer between the base 3a of the carriage 3 and the sensor substrate 12a and changing the distance between the reflecting mirror 14 and the light receiving surface of the line sensor 12. Has been done. This operation is performed while checking the in-focus state. However, since the depth of field of the rod lens array 15 is extremely small, mounting and dismounting of the sensor substrate 12a is repeated to form a spacer having an appropriate thickness. Like that. For this reason, the adjustment work is complicated.
[0010]
Therefore, the present invention provides an image reading apparatus which can easily adjust the position of the rod lens array having a small depth of field on the optical path and can surely focus on the light receiving surface of the CCD. It is intended to be.
[0011]
[Means for Solving the Problems]
As a technical means for achieving the above object, an image reading apparatus according to the present invention includes a CCD for acquiring image data from a document while moving along a document placed on a platen glass. In an image reading apparatus in which a rod lens array is used in a reading optical system for guiding reflected light from a document, the rod can be moved in the optical axis direction of the rod lens array with respect to a carriage on which the CCD and the rod lens array are mounted. An adjusting member fixed to a predetermined position of the carriage is provided, and the rod lens array is held by the adjusting member.
[0012]
In other words, by moving the adjusting member, the rod lens array can be moved in the optical axis direction with respect to the carriage, so that the position of the rod lens array on the optical path of the reading optical system can be changed. it can. Thereby, the focus position of the rod lens array can be adjusted, and the light receiving surface of the CCD can be focused.
[0013]
After the adjustment of the focal position, the adjusting member is fixed to the carriage. Since fastening means such as screwing can be used for this fixing, the rod lens array is prevented from being displaced on the optical axis after positioning, and it is easy to readjust if it is displaced.
[0014]
An image reading apparatus according to a second aspect of the present invention is characterized in that the adjusting member is a lid that covers the base for covering a CCD or the like incorporated in the base of the carriage.
[0015]
The rod lens array is held by the lid, and the rod lens array is set on the optical path of the reading optical system in a state where the lid is placed on the base of the carriage. Since this lid is movable in the optical axis direction of the rod lens array with respect to the base of the carriage, the position of the lid in the optical path direction of the rod lens array is adjusted by adjusting the position of the lid with respect to the base. Therefore, the focal position of the rod lens array can be adjusted. After the focal position is adjusted, if the lid is fixed to the base with screws or the like, the rod lens array is set at a predetermined position on the optical path.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an image reading apparatus according to the present invention will be specifically described based on the illustrated preferred embodiments. The same parts as those in the conventional structure described above are denoted by the same reference numerals as those shown in FIG.
[0017]
FIG. 1 is a sectional view of the carriage 20, and corresponds to FIG. The carriage 20 is covered with a lid 22 in a state where the first reflecting mirror 13, the second reflecting mirror 14, and the line sensor 12 are incorporated in a base 21. The rod lens array 15 is held by the lid 22. As shown in FIG. 1, the lid 22 is bent such that the holding portion 22 a holding the rod lens array 15 is lower than the fixing portion 22 b that covers the upper part of the second reflecting mirror 14. The rod lens array 15 is attached to the lower surface of the holding portion 22a by an adhesive or the like. When the lid 22 is placed on the base 21, the rod lens array 15 is located between the first reflecting mirror 13 and the second reflecting mirror 13 and 14 are located in the optical path formed by them.
[0018]
The lid 22 is movable in the optical axis direction of the rod lens array 15. As shown in FIG. 2, a long hole 22c whose longitudinal direction is the optical axis direction is formed at both ends of the lid 22 in the longitudinal direction. The cover 22 is fixed to the base 21 by fastening a set screw (not shown) penetrating the elongated hole 22c to the female screw portion 21a formed on the base 21. Therefore, the lid 22 is movable with the long hole 22c being guided by the set screw.
[0019]
When assembling the carriage 3, the first reflecting mirror 13, the second reflecting mirror 14, and the sensor substrate 12 a on which the line sensor 12 is mounted are attached to predetermined positions of the base 21. On the other hand, the rod lens array 15 is attached to the lower surface of the holding portion 22a of the lid 22 with an adhesive or another appropriate method. When the lid 22 is put on the base 21, the rod lens array 15 is located between the first reflecting mirror 13 and the second reflecting mirror 14, and the optical axis of the rod lens array 15 is 14 optical paths. Then, a set screw (not shown) that has passed through the long hole 22c of the lid 22 is screwed into the female screw portion 21a and temporarily fixed. In this state, since the lid 22 can be moved in the direction of the optical axis of the rod lens array 15, when the lid 22 is moved in the same direction, the image forming position of the light transmitted through the rod lens array 15 changes. I do. Therefore, after adjusting the position of the rod lens array 15 so as to focus on the light receiving surface of the line sensor 12, the temporarily fixed set screw is tightened to fix the lid 22 to the base 21.
[0020]
In this embodiment, the structure in which the cover 22 serving as the adjustment member holds the rod lens array 15 and the cover 22 is movable has been described. May be separately provided as an adjusting member, and the holding plate may be movable in the optical axis direction of the rod lens array 15 to adjust the position of the rod lens array 15 on the optical path.
[0021]
【The invention's effect】
As described above, according to the image reading apparatus of the present invention, the rod lens array is moved in the optical axis direction by moving the adjustment member holding the rod lens array with respect to the carriage. Therefore, the focal position of the rod lens array can be adjusted by moving the adjusting member. For this reason, adjustment work can be simplified and workability can be improved.
[0022]
According to the image reading apparatus of the second aspect of the present invention, since the cover of the carriage is movable relative to the base and used as the adjusting member, the structure is simplified, and the structure using the existing carriage can be adopted. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a schematic structure of a carriage of an image reading apparatus according to the present invention.
FIG. 2 is a plan view of the carriage shown in FIG.
FIG. 3 is a cross-sectional view illustrating a carriage of a conventional image reading apparatus, and corresponds to FIG.
FIG. 4 is an exploded perspective view illustrating the structure of an image scanner as an image reading device.
FIG. 5 is an external view of an image scanner.
[Explanation of symbols]
11 light source 12 CCD
12a Sensor substrate 13 First reflecting mirror 14 Second reflecting mirror 15 Rod lens array 20 Carriage 21 Base 21a Female screw part 22 Lid (adjusting member)
22a holding part 22b fixing part

Claims (2)

An image in which a rod lens array is used in a reading optical system for guiding reflected light from the original to a photoelectric conversion element for acquiring image data from the original while moving along the original placed on a platen glass In the reader,
For the carriage on which the photoelectric conversion element and the rod lens array are mounted, an adjustment member that is movable in the optical axis direction of the rod lens array and is fixed to a predetermined position of the carriage is provided.
An image reading apparatus, wherein the adjustment member holds the rod lens array. 2. The image reading apparatus according to claim 1, wherein the adjusting member is a lid that covers the photoelectric conversion element and the like incorporated in the base of the carriage.

Images