JPH07120843A - Image reader - Google Patents

Abstract

PURPOSE:To reduce the dispersion of the light quantity of each line and the dispersion of condensed light on a contact glass, to realize high efficiency and stable illumination distribution state and to obtain accurate read information. CONSTITUTION:In this image reader reading an image by forming the image light of an original image illuminated by an illumination optical system into the image on a read means through an image forming optical system, the illumination optical system is constituted of a light source 2, plural 1st reflecting members 3 condensing and reflecting the light from the light source 2, and 2nd reflecting members 4 to 7 sharing a focal point P2 on which the light is condensed by the member 3, setting the focal point P2 as a secondary light source, and condensing the light from the secondary light source or distributing the light in the state of parallel light beams.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, and can be applied to an illumination system for illuminating a document surface of an image reading apparatus used for, for example, a color copying machine, a facsimile, or an input device of a computer. ,In particular,
The present invention relates to an image reading device that can realize a highly efficient and stable illumination distribution state and obtain accurate read information.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional image reading apparatus.
The image reading apparatus uses an image light of a document image as shown in FIG.
The light source 101, the reflecting members 102 and 103, the first, second and third mirrors 104, 105 and 106, and the condenser lens 10.
An image is formed through an image forming optical system consisting of 7
Separation is performed using a prism 108 for color separation, and three reading elements (CCD) 109, 110, 111 are arranged at positions corresponding to the separated color image forming lights to read a color original. ing. Note that FIG.
In, reference numeral 112 is a contact glass.

However, in the image reading apparatus using such a color separation prism 108, the prism 108
It is necessary to provide three CCDs for the R, G, B (red, blue, green) color image lights separated by, and in addition to this, the number of other parts is increased and the prism is Since it is usually expensive, the cost is high, and CCD position adjustment must be performed for each R, G, B color.
Since the position adjustment is troublesome and difficult, there is a problem that it takes a long time to perform the CCD adjustment.

Therefore, as a conventional image reading apparatus capable of solving such a problem, there is an apparatus using a 3-line CCD 113 as shown in FIG.
An image reading apparatus using the line CCD 113 is shown in FIG.
As can be seen from FIG. 8 which is a partially enlarged view of R, G, B
The reading position of is shifted in the sub-scanning direction.

[0005]

However, in the conventional image reading apparatus as described above, the illumination optical system is
Illumination light from the illumination light source 101 is reflected by the reflecting members 102, 103.
Since it is configured to focus on one straight line G in the main scanning direction by using, etc., only one line (G in the figure) on the CCD corresponding to the straight line G is illuminated and the other two lines (R and B in the figure). ) Had a problem that the amount of light was insufficient.

[0006] Therefore, as a conventional image reading apparatus capable of solving this problem, there is known one using a reflective material having a shape for illuminating three lines. There is a difference in the amount of light that is illuminated,
If the condensing width is widened to cover three lines, the amount of light is reduced, and there is a problem in that the read information of each line varies and the reading becomes inaccurate.

Next, in the conventional image reading apparatus reported in Japanese Unexamined Patent Publication No. 1-181377, the CCD R,
It is described that each of G and B is provided with a reflecting plate for collecting light in a one-to-one correspondence, but there is a problem that read information becomes inaccurate if the position of the CCD is slightly displaced. Further, in the conventional image reading apparatus, the reflecting member 102 having the same and a plurality of continuous elliptical shapes.
(Or the reflecting member 103), as shown in FIG. 9, the distance from the light source is remarkably different depending on, for example, each part of the optical paths d and e of the reflecting member 102. The variation of the light collection of the
02 becomes larger as the distance from the optical path becomes smaller, so the optical path d and the optical path e
Therefore, the dispersion of the light condensing becomes larger in the optical path e closer to the light source 1, and the reflecting member 102 and the reflecting member 10 in FIG.
3 causes a light amount difference, and therefore, when a document having a step such as a cut and pasted document is read, the amount of light incident on the CCD is lower than when a flat document having no step is read, and thus a shadow is likely to occur. There was a problem of being lost.

Next, in the conventional image reading apparatus, the illumination system using the reflecting member is designed so that the area of the reflecting member is as large as possible in order to increase the light amount. As shown, a plurality of reflecting members 10
2 and 103, emission angles α, β of light from the light source 101
Are not equal to each other, the light collection efficiency of each of the reflecting members 102 and 103 varies, the read information of each line on the contact glass 112 varies, and the reading becomes inaccurate. there were.

Therefore, according to the present invention, it is possible to realize a highly efficient and stable illumination distribution state by reducing the variation of the light amount of each line and the variation of the light condensing on the contact glass. An object is to provide an image reading device that can obtain read information.

[0010]

The invention according to claim 1 is
In an image reading apparatus for reading an image by imaging the image light of a document image illuminated by an illumination optical system on a reading means via an imaging optical system, the illumination optical system collects a light source and light from the light source. A plurality of first reflecting members that emit light and reflect the light, and a focused focus of the first reflective member are shared, and the focus is used as a secondary light source, and light from the secondary light source is focused or It is characterized in that it is composed of a second reflecting member that distributes light in the form of parallel rays.

According to a second aspect of the present invention, in an image reading device for reading an image by forming image light of a document image illuminated by an illumination optical system on a reading means through an imaging optical system, the illumination optical system is used. , Collecting the light from the linear light source and the linear light source arranged in a fan-cylindrical shape around the linear light source and facing each other with the optical path axis from the imaging optical system to the document surface sandwiched therebetween. A plurality of reflecting members that reflect light or light rays to have a constant density, and the plurality of reflecting members have one of the focal points at the center of the linear light source and the other focal point above the contact glass. When placed, a first reflecting member having an elliptical or polygonal plane where the light is condensed or has a constant light density, and one focal point is between the reflecting members having the focal point as the center of the light source and the other focal point. Second reflection that irradiates the reflecting surface with light A third material having an ellipse or a polygonal plane which shares a focal point collected by a different reflecting member with the material and which condenses the irradiation light from the different reflecting member or has a constant light ray density, with the focal point as one focal point. And a reflective member.

[0012]

According to the present invention, in the image reading apparatus for reading the image by forming the image light of the original image illuminated by the illumination optical system on the reading means through the imaging optical system, the illumination optical system is used. A light source and a plurality of first reflecting members that collect and reflect light from the light source, share a focused focus of the first reflecting member, and use the focus as a secondary light source, and A second reflecting member that condenses or distributes light from the secondary light source in the form of parallel rays.

In the conventional image reading apparatus, the light at the upper right of the light source is excluded by the light shielding plate by the reflecting member that illuminates the light of the linear light source to the reading area of the document surface through the reflecting member. In the described invention, in the illumination optical system, after the light from the light source is condensed and reflected by the plurality of first reflecting members, the condensed focus of the first reflecting member is shared and the focal points are The secondary light source serves as a secondary light source, and the light from the secondary light source can be condensed or distributed in the form of parallel rays by the second reflecting member, so that it is possible to irradiate the facing reflecting member from the reflecting member. In addition to realizing an efficient illumination system, the center of the light source can be used as one focal point and the other focal point can be provided between the facing reflecting plates, so that a stable illumination distribution state can be realized. You can Therefore, since it is possible to obtain a highly efficient and stable illumination distribution state, it is possible to obtain accurate read information.

According to a second aspect of the present invention, in the image reading apparatus for reading the image by forming the image light of the original image illuminated by the illumination optical system on the reading means through the imaging optical system, the illumination optical system is used. , Collecting the light from the linear light source and the linear light source arranged in a fan-cylindrical shape around the linear light source and facing each other with the optical path axis from the imaging optical system to the document surface sandwiched therebetween. A plurality of reflecting members that reflect light or light rays to have a constant density, and the plurality of reflecting members have one of the focal points at the center of the linear light source and the other focal point above the contact glass. The first reflecting member having an elliptical or polygonal plane where the light is condensed or has a constant light density, and one focal point is the center of the light source, and the other focal point is between the facing reflecting members, To irradiate the reflective surface with light A projecting member shares a focal point collected by a different reflecting member, and has an ellipse or a polygonal plane that condenses irradiation light from a different reflecting member or has a constant light beam density with the focal point as one focal point. It is configured so as to be configured by the third reflection member.

For this reason, a plurality of reflecting members are arranged around the linear light source in a fan-cylindrical shape and face each other with the ray axis from the imaging optical system to the original surface sandwiched therebetween.
It has an elliptical or polygonal plane with the light from the linear light source being condensed or reflected so that the light beam density is constant, with the center of the linear light source as one of the focal points and the other focal point placed above the contact glass. A first reflection member (a reflection member of the plurality of reflection members) is used to make the light condensing or light beam density constant, and one focal point is the center of the light source, and the other focal point is between the facing members. The two reflecting members (reflecting members of the plurality of reflecting members) irradiate the facing reflecting surfaces, and the different focusing members share the focused light. The irradiation light from the member can be condensed or made to have a constant light beam density by the third reflecting member (reflecting member among the plurality of reflecting members) having an elliptical or polygonal plane. 1 of the invention Besides it is possible to obtain a result, the light rays reflected by the reflection member, it is possible to light distribution to larger width than the surface of the document required illumination distribution width, it is possible to efficiently realize the stable illumination distribution.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a diagram showing a configuration of an illumination optical system in an image reading apparatus according to a first embodiment of the present invention (claim 1), and FIG. 2 is a whole showing a configuration of a reflecting member shown in FIG. It is a perspective view. In the image reading apparatus of the present embodiment, the image light of the image original illuminated by the illumination optical system is imaged on the reading means via the imaging optical system to read the image, and in particular, the light distribution of the illumination optical system, That is, the characteristic part according to claim 1 will be specifically described.

In this embodiment, as shown in FIG. 1, the center of the light source 1 arranged under the contact glass 1 is P ₁ , the focus P ₂ is above the reflecting member, and the light source 1 emits light to the upper right in the figure. The reflected light is reflected by the reflecting member 3 arranged in the upper right position of the light source 1, and then reflected by the reflecting member 6 arranged in a position facing the reflecting member 3. The reflecting member 3 is
It is composed of an elliptical or polygonal plane whose focal points are the light source centers P ₁ and P ₂ , and is connected to the reflecting member 4 disposed below the light source 2 and is connected to this reflecting member 4 and extends to the left of the light source 2. It is connected to the reflective member 5. In addition, the reflection member 6
Is arranged at a position facing the reflecting members 3, 4, 5 and is connected to the reflecting member 7 extending to the upper left of the light source 2.

In this way, an illumination optical system in which the light from the light source 2 is reflected by the reflecting member 3 and the light reflected by the reflecting member 3 is further reflected by the reflecting member 6, is provided from the reflecting member 3 to the reflecting member 6. The focal point P ₂ is provided in the optical path of the above and above the reflecting members 4, 5 and 6, and the light is reflected from the reflecting member 3 having the elliptical or polygonal plane whose focal points are the light source centers P ₁ and P ₂ to the reflecting member 6. The light beam is made into a parallel light beam by the reflecting member 6 and reaches the document surface. In addition, in FIG. 1, A is
3 shows a document surface light distribution distribution state in which the document surface on the contact glass 1 is illuminated by the reflecting members 3 and 6.

As described above, in this embodiment, the light from the light source 2 is focused on the focal point P ₂ by the reflecting member 3 and the focal point P ₂ is used as the secondary light source. The reflecting members 4 to 7 are arranged so that the light distribution state of the illuminated light is shown.
Thus, the light rays emitted from the light source 2 or another reflection member can be made into parallel rays and condensed on the original surface. For this reason, the light rays from the light source 2 are made into parallel light rays by the reflecting members 4 to 7, and each of the reflecting members 4 to 4 has a width larger than the required distribution width.
Since it can be focused by 7, contact glass 1
Even if the illumination distribution width on the upper document surface varies, a stable illumination distribution can be obtained with the required distribution width. Here, the required distribution width B means a width obtained by absorbing the optical axis variation width D of the imaging system in the reading width C as shown in FIG. In FIGS. 3 and 4, 8 is a light shielding plate, D is an illumination distribution width, and E is an optical axis. (Embodiment 2) Next, FIG. 5 is a diagram showing a configuration of an illumination optical system in an image reading apparatus according to Embodiment 2 of the present invention (claim 2). The image reading apparatus of the present embodiment is for reading the image by forming the image light of the original image illuminated by the illumination optical system on the reading means through the imaging optical system to read the image. That is, the characteristic part according to claim 2 will be specifically described. The reflecting member of this embodiment also has the same structure as that of the first embodiment shown in FIG. here,
A reflecting member 4 arranged below the light source 2 of Example 1 of FIG. 1, and a reflecting member 3 connected to the reflecting member 4 and extending to the light source 2.
The processing in the vicinity will be specifically described.

In this embodiment, the portion a which constitutes the reflecting member 5
The minute is the light source center P at the left end of the reflecting member 4. ₁Of the reflection member 4
Left end point and point Q that is outside the required distribution width on the document surface
₁Adjacent to the angle α formed by and. And this angle α
Is equal to the reflection angle from the light source 2 by the reflection member 4.
Or an ellipse or a polygonal plane, which is configured with an angle larger than that
The reflecting member 4 is configured to have. For this reason,
In the embodiment, the reflecting member 4 having an elliptical or polygonal plane.
To make the reflected light as close as possible to parallel rays.
And the reflecting members 5 and 7 are the same as the reflecting member 4.
Since it is composed of elliptical or polygonal planes like
Reflecting the radiated light from 4 in the form of parallel rays on the original surface
You can Therefore, the same effect as that of the first embodiment can be obtained.
In addition, the light rays reflected by the reflecting member must be reflected on the document surface.
It is possible to distribute the light to a width larger than the required irradiation distribution width.
It is possible to obtain a stable lighting distribution state efficiently.
It

[0021]

According to the present invention, it is possible to realize a highly efficient and stable illumination distribution state by reducing the variation of the light amount of each line and the variation of the condensing on the contact glass. The effect is that accurate read information can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an illumination optical system in an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is an overall perspective view showing a configuration of a reflecting member shown in FIG.

FIG. 3 is a diagram showing a light distribution state of a light source which irradiates a document surface with each reflecting member shown in FIG.

FIG. 4 is a diagram showing that the necessary distribution width shown in FIG. 3 is a width obtained by absorbing a variation width of the optical axis of the imaging system in the reading width.

FIG. 5 is a diagram showing a configuration of an illumination optical system in an image reading apparatus according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of an image reading apparatus using a conventional color separation prism.

FIG. 7 is a diagram showing a configuration of an image reading apparatus using a conventional 3-line CCD.

8 is an enlarged view showing a configuration of a light source, a reflecting member, a first mirror and a contact glass portion of the image reading device shown in FIG.

FIG. 9 is a diagram showing a state in which a distance from a light source is different depending on respective portions of optical paths d and e of an elliptical reflecting member in a conventional image reading apparatus.

FIG. 10 is a diagram showing a state in which, in a conventional image reading apparatus, the emission angles of light from a light source with respect to a plurality of reflecting members are different.

[Explanation of symbols]

 1 Contact glass 2 Light source 3, 4, 5, 6, 7 Reflecting member 8 Light-shielding plate

Claims (2)

[Claims] 1. An image reading apparatus for reading an image by forming image light of a document image illuminated by an illumination optical system on a reading means through an imaging optical system to read the image, wherein the illumination optical system comprises a light source and a light source. And a plurality of first reflecting members that collect and reflect the light from the first reflecting member, share the focused focus of the first reflecting member, and use the focus as a secondary light source, and from the secondary light source. An image reading apparatus comprising a second reflecting member that condenses light or distributes the light into parallel rays. 2. An image reading apparatus for reading an image by forming image light of a document image illuminated by an illumination optical system on a reading means through an imaging optical system to read the image, wherein the illumination optical system comprises a linear light source. The light from the linear light source, which is arranged in a fan-cylindrical shape around the linear light source and faces each other with the optical path axis from the imaging optical system to the document surface sandwiched, is condensed or has a constant light beam density. And a plurality of reflecting members that reflect light such that the center of the linear light source is one of the focal points and the other focal point is located above the contact glass to collect or collect light. A first reflecting member having an elliptical or polygonal plane where the light density is constant, and one focal point as a light source center, another focal point between the facing reflecting members, and light on the facing reflecting surface. Second reflecting member for irradiating and different reflecting portion And a third reflecting member having an elliptical or polygonal plane that converges the irradiation light from different reflecting members or has a constant light beam density while sharing the same focused focal point. An image reading device characterized by the following.