JPH09294193A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in image quality due to a foreign material adhered to a position close to an original face by placing an electrostatic attracting member to a position at the outside of an image area of a mirror placed in the vicinity of a contact glass. SOLUTION: A read optical system has a contact glass 101 supporting an original 100 to its upper side, a light source 102, a 1st mirror 103, a 2nd mirror 104, a 3rd mirror 105, an image pickup lens 106, and an image pickup element 107. Then the light source 102 and the 1st mirror 103 form a 1st running body A, and the 2nd, 3rd mirrors 104, 105 form a 2nd running body B. Since a distance between the mirror 103 and the original face is close, the image pickup lens is well focused. Thus, even a very small foreign material on the mirror 103 is read and the image is formed on the image pickup element 7 resulting in deteriorating the image quality. Then an electrostatic attracting member 108 is placed at a position at both end ridges of the mirror 103 in the subscanning direction at the outside of an optical path range. Thus, the attracting member 108 absorbs and adsorbs the foreign material electrostatically so as to eliminate the foreign material efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer,
The present invention relates to a reading unit of an image forming apparatus such as a facsimile machine or an image reading apparatus used for a scanner or the like, and particularly, to prevent deterioration of image quality caused by foreign matter adhering to optical components such as mirrors constituting a reading optical system. The present invention relates to an image reading device having a configuration capable of

[0002]

2. Description of the Related Art An image reading apparatus as described above is composed of optical components such as a carriage, a lens and a mirror which are located directly below a contact glass on which a document is set, and a light source, a mirror and the like are mounted on the carriage. When a document set on the contact glass is irradiated with light from a light source on the carriage directly below the contact glass, the reflected light of the document is reflected on the photoconductor through a mirror, lens, or CCD (imaging device). It is imaged. By the way, fine foreign substances such as paper dust and toner are suspended in the image reading device. When these foreign substances adhere to optical components such as a light source, a mirror, and a lens, the read image is moved in the sub-scanning direction. Extended white or black stripes are formed, which causes deterioration of the quality of the read image.

[0003]

In order to solve such a problem, Japanese Patent Laid-Open No. 4-156165 discloses a method of attaching a dust-proof means having a dust-proof action to an imaging lens and / or an image pickup device, so that the adhesion is prevented. A technique for reducing maintenance work for cleaning dust and the like is disclosed. However, since the dustproof means mainly targets the imaging lens and the image pickup element which are distant from the document surface, no consideration is given to dustproof measures for the optical parts, that is, the light source and the mirror, which are located closer to the document surface. In addition, since the mirror located near the original surface is close to the original surface, the focus of the imaging lens is in this position, and therefore, minute foreign matter on the first mirror is also bound to the imaging element 107. The image is likely to be deteriorated. Therefore, it is a one-handed drop unless foreign matter on the mirror near the original is prevented from adhering. Moreover, in the technique described in this publication, the structure of the dustproof means is complicated, which is a cost problem, and it is not possible to apply this structure to the light source and the mirror as it is.

The present invention has been made in view of the above, and provides an image reading apparatus having a reading optical system which guides reflected light of a document emitted from a light source and reflected on a document surface in a predetermined direction by using a mirror, a lens and the like. It is an object of the present invention to prevent deterioration of image quality caused by foreign matter adhering to a mirror and a light source arranged near the document surface. That is, according to the first aspect of the present invention, white stripes or blacks in the sub-scanning direction are formed on the read image due to the adhesion of fine foreign matter (dust such as paper dust) to a mirror or the like close to the document surface. In order to prevent the formation of streaks, an electrostatic adsorbent is provided near the optical axis to adsorb fine foreign particles that float before adhering to the optical axis onto the electrostatic adsorbent, and The objective is to obtain a high-quality read image that is not affected by such foreign matter. According to the invention of claim 2, in order to prevent the electrostatic adsorption material from being contaminated due to the electrostatic adsorption material continuing to adsorb fine foreign matters floating in the electrolysis according to claim 1, The purpose is to facilitate the attachment and detachment and replacement of the electrostatic adsorption material.

[0005]

[Means for Solving the Problems] To achieve the above object,
According to a first aspect of the present invention, in an image reading apparatus configured to guide light emitted from a light source and reflected on a document surface in a predetermined direction through a mirror, a lens, and a transparent member, the mirror located near the document surface. The electrostatic attraction material is arranged outside the optical path region of the transparent member and in the vicinity of the region to attract dust. The invention of claim 2 is
It is characterized in that the electrostatic adsorption material is replaceable.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIG. 1 is a schematic configuration explanatory view of an example of a reading optical system of an image reading apparatus to which the present invention is applied. This reading optical system includes a contact glass 101 for supporting an original 100 on its upper surface, a light source 102, and a first glass. Mirror 103, second mirror 104, and third mirror 10
5, an image pickup lens 106, and an image pickup device (CCD) 107
And The light source 102 and the first mirror 103 have a first
Of the second traveling body (carriage) A, and the second and third mirrors 104 and 105 constitute the second traveling body (carriage) B. Light emitted from the light source 102 and reflected by the original 100 is reflected by the first mirror 103, the second mirror 104, and the third mirror 104.
After passing through the imaging lens 106 via the mirror 105, it reaches the photoelectric element (CCD) 107. First mirror
The image pickup lens 103 is in focus because it is close to the document surface. Therefore, even a fine foreign substance on the first mirror is read and an image is formed on the image pickup element 107, which causes a deterioration in image quality.

Therefore, in the present invention, in order to prevent fine foreign matters such as black streaks and white streaks that cause abnormal images from adhering to the optical axis of the first mirror 103, as shown in the drawing,
The electrostatic adsorbent 108 is provided at both ends of the first mirror 103 in the sub-scanning direction and outside the optical path range (outside the effective image information area).
Was placed. Since the electrostatic adsorbing material electrostatically attracts and adsorbs foreign matter, it is possible to effectively remove foreign matter without making a particularly large-scale modification. It should be noted that the electrostatic adsorption material 108 is the mirrors 104, 1 other than the first mirror 103.
You may provide along the edge of 05 outside the optical axis range. As the electrostatic adsorption material, for example, a material used for a cleaning tool called a so-called chemical rag is used.

2 (a) and 2 (b) are a perspective view and a sectional view taken along line XX of an example of a structure for attaching the electrostatic attraction material to the mirror. In this example, a rectangular annular bracket 115 having a shape capable of covering the outer circumference of the mirror is covered from the front surface of the mirror 103 as shown in (b), and a stopper 115a integrated with the bracket is used to fix the mirror. It is prevented from falling off. In addition, the electrostatic adsorption material 108 is used for the bracket 11
It is fixed by being pinched and held between the front surface 115b of No. 5 and the front surface of the mirror. In this example, the bracket 115
Since it is locked to the mirror by the elastic force (snap fit) of the stopper 115a, it can be easily separated from the mirror by rotating the stopper 115a each time. It can be removed and replaced.

FIG. 3 is a diagram showing an outline of an optical system of an image reading apparatus according to another embodiment of the present invention. This reading optical system includes mirrors 103, 104 and 105, a lens 106 and an image pickup element 107. It is an integrated traveling body type. In this reading optical system, the light source 102 facing the original 100 is housed in the box body 130, and the mirror 103 located immediately above the light source 102 is arranged outside the box body via a dustproof glass (transparent member) 109. Has been done. The light from the light source 102 illuminates the original 100 directly below the contact glass 101, and the original reflected light passes through the dustproof glass 109 and passes through the first mirror 103, the second mirror 104, and the third mirror 105. After passing through the imaging lens 106, the photoelectric device (CC
D) Reach 107. Dustproof glass 109 and the first mirror
In 103, since the distance from the document surface is short, the image pickup lens is in focus. Therefore, the first Mira-1
The fine foreign matter on 03 is also read, and the image quality is deteriorated. Therefore, in the present embodiment, in order to prevent fine foreign matter that causes an abnormal image from adhering on the optical axis (effective image area) of the dust-proof glass 109 or the first mirror 103, the light of the dust-proof glass 109 is prevented. The electrostatic adsorption material 108 is arranged outside the axial range. The electrostatic adsorbing material 108 is effective in preventing dust from adhering to the reflecting surface of the first mirror 103 located immediately adjacent to the dust-proof glass 109 and immediately attracting and capturing foreign matter. Even in this embodiment, the electrostatic attraction material may be provided on another mirror.

FIG. 4 shows an example of the support structure for the electrostatic adsorption material in the embodiment shown in FIG. 3, and in this example, the electrostatic adsorption material 1 is used.
The L-shaped bracket 112 to which 08 is fixed is detachably screwed to the bracket 131 supporting the dustproof glass 109 by using the screw 113. For this reason, while being easily assembled to the existing bracket 131, replacement when the electrostatic adsorption material 108 becomes dirty becomes easy.

Next, FIGS. 5 (a) and 5 (b) are a front view and a partial perspective view of a main part of another embodiment of the present invention. In this example,
The first mirror 103 is supported by the fixing member 140 on the back side of the support surface 141, and the electrostatic adsorption material 108 is fixed to the edge of the surface of the support surface 141. The reflection surface of the first mirror 103 is exposed from the slit 141a provided in the center of the support surface 141, and the electrostatic adsorption material 108 is located on both sides of the exposed reflection surface. Further, a slit 142 a for an optical path toward the dustproof glass 109 is opened at an appropriate position of the intermediate portion 142 of the fixing member 140. This fixing member 1
40 is also replaceably fixed to the bracket 131 with a screw 113.

[0012]

According to the first aspect of the present invention, since the electrostatic adsorption material is arranged outside the image area of the mirror located near the contact glass, fine foreign matter adheres to the mirror or the like close to the document surface to read the image. It is possible to prevent the quality of the product from deteriorating. Since the mirror close to the document surface is focused on the image pickup mirror located in the latter stage, even a minute foreign substance adversely affects the image quality.Therefore, an electrostatic adsorption material is placed on this mirror to attach it to the mirror surface. The above adverse effect can be prevented by sucking and capturing the foreign matter to be captured. According to the invention of claim 2, since the electrostatic adsorption member is easily attached and detached, in addition to the effect of claim 1, the quality of the read image can be maintained over time and maintenance in the market can be facilitated. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part configuration of an image reading apparatus according to an embodiment of the present invention.

2 (a) and 2 (b) are views showing a method of attaching the electrostatic attraction material in FIG.

FIG. 3 is a main part configuration diagram of another embodiment of the present invention.

FIG. 4 is a diagram showing an example of a detachable mounting structure of the embodiment example of FIG. 3;

5 (a) and 5 (b) are a front view and a partial perspective view showing a main part configuration of another embodiment of the present invention.

[Explanation of symbols]

100 originals, 101 contact glass, 102 light source, 103 first mirror, 104 second mirror, 1
05 Third mirror, 106 Imaging lens, 107 Imaging device (CCD), 108 Electrostatic adsorption material,

Claims (2)

[Claims] 1. An image reading apparatus configured to guide light emitted from a light source and reflected on a document surface in a predetermined direction through a mirror, a lens, and a transparent member, and a mirror located near the document surface. An image reading apparatus characterized in that an electrostatic adsorption material is arranged outside the optical path region of the transparent member and in the vicinity of the optical path region to adsorb dust. 2. The image reading apparatus according to claim 1, wherein the electrostatic adsorption material is replaceable.