JP3062437B2 - Image input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copying machine,
The present invention relates to an image input device used for a color scanner such as a stencil printing machine and a facsimile.

[0002]

2. Description of the Related Art The color separation method in a color scanner is as follows.
There are three methods: a light source switching method, a three-line image sensor method, and a color separation filter switching method. In order to reduce the size of the apparatus and reduce the price, a color separation filter switching method is widely adopted. As an example, for example,
As described in JP-A-195533, there is a type in which a plurality of color filters are provided to be able to advance and retreat in an optical path from a subject to a photoreceptor. In addition, Japanese Patent Application Laid-Open No.
As described in Japanese Patent Application Laid-Open Publication No. H10-157, an additive-type filter corresponding to the three primary colors of light and a subtractive-type filter corresponding to the three primary colors of dyes and pigments are selectively advanced into the optical path. is there.

[0003]

Here, no matter which filter is used for color separation, as shown in FIG.
Although it is necessary to provide an imaging lens 2 in the optical path 1, since the color scanner uses the entire visible light region, chromatic aberration due to the imaging lens 2 occurs. For example, when comparing the light 3 _R light 3 _B and red components of the blue component, an imaging lens than the light 3 _R component of wavelength longer red towards the light 3 _B components of wavelength shorter Blue The focus will be on a position close to 2. Conventionally, in order to remove the influence of such chromatic aberration, correction is performed using a correction lens 4 as shown in FIG. 3 or using a plurality of lenses.
There is a problem that the configuration of the imaging lens becomes complicated and the cost increases.

[0004]

According to the present invention, there is provided a light source for irradiating an original with illumination light, an imaging lens for forming an image of reflected light from the original, and a first filter for reflecting the reflected light from the original.
A second filter; a color separation filter unit configured to separate into primary colors by a third filter; and the first filter
And the second filter and the third filter
In a color scanner having a photoelectric conversion section for converting into an electric signal degradation light color separation I, the first Fi
Filter, the second filter, and the third filter
The color separation filter section having the color separation filter section is disposed on the document side of the imaging lens, and each of the filters of each color of the color separation filter section independently advances and retreats in a direction orthogonal to the optical path of the reflected light from the document. And a movable body interlocked with the movement of the filter that advances perpendicularly to the optical path, and
A spring for urging the photoelectric conversion unit so as to contact the optical path of the reflected light from the original in the coaxial direction, and the photoelectric conversion unit is moved from the original in accordance with the movement of the movable body .
Optical path length changing means for changing the optical path length between the imaging lens and the photoelectric conversion unit by moving the optical path in the coaxial direction with the optical path of the reflected light is provided. Therefore, the chromatic aberration can be corrected by changing the optical path length between the imaging lens and the photoelectric conversion unit according to the type of the filter that enters the optical path of the reflected light from the document, thereby simplifying the structure of the lens system. Since the photoelectric conversion element is urged by a spring and pressed against the movable body, the photoelectric conversion element can be moved with high accuracy and does not change with time.

[0005]

FIG. 1 shows an embodiment of the present invention. An embodiment of the present invention is characterized in that a difference in focal length due to a difference in light wavelength is corrected by moving a photoelectric conversion unit on an optical axis according to a filter to be used. Color separation filter unit 10 according to one embodiment of the present invention
Is a first filter 10 that transmits light of blue (B) component.
_B , a second filter 10 _G that transmits light of the green (G) component, and a third filter 10 _R that transmits light of the red (R) component. These filters 10 _B and 10 _B
G and 10 _R have the same thickness and the same refractive index, and are selectively advanced one by one into the optical path 1. A movable table 11 holding the photoelectric conversion unit 5 is movably held in the optical path length direction by a guide 12, and is formed by a spring 13 on the imaging lens 2.
It is urged in a direction away from it.

Thus, the arm 14 as a movable body is held rotatably about the support shaft 15. At one end of the arm 14, projections 16 and 17 are formed to interfere with the first filter 10 _B and the second filter 10 _G when they enter the optical path 1, and the movable table 11 at the other end. A contact portion 18 that contacts the end surface of the contact hole is formed. This arm 1
4 receives the pressure of the spring 13 via the movable base 11, but is normally stabilized at the position shown in FIG. 1 by a stopper (not shown). Note that the projection 16 is projected more toward the optical axis of the imaging lens 2 than the projection 17. The movable table 11 holding the photoelectric conversion unit 5, the spring 13, and the arm 14 form an optical path length changing unit.

[0007] In such a configuration, when the filter 10 _B are advanced in the optical path 1 in order to obtain an image of blue (B), the arms 14 by interference between projection 16 and the filter 10 _B support shaft The movable table 11 is rotated clockwise around the center 15, and is pressed by the contact portion 18. Thereby, the optical path length between the imaging lens 2 and the photoelectric conversion unit 5 becomes the shortest. Green when the filter 10 _G in order to obtain an image of the (G) is advanced into the optical path 1, rotated about the arm 14 supporting shaft 15 by interference between projection 17 and the filter 10 _G clockwise Then, the moving table 11 is pressed by the contact portion 18. However, since the protrusion amount of the protrusion 17 is small, the optical path length between the imaging lens 2 and the photoelectric conversion unit 5 is a case where a blue (B) image is obtained. It becomes shorter next. When the filter 10 _R was advanced into the optical path 1 in order to obtain an image of red (R), the arm 14 remains stationary since the filter 10 _R not any interference, imaging lens 2 and the photoelectric conversion The optical path length with the part 5 is the shortest.

Therefore, the shorter the wavelength of the light component, the shorter the focal length, but the filters 10 _B , 10 _{B
When G} and _10R are selectively advanced into the optical path 1, the optical path length can be automatically and optimally changed by the operation of the arm 14, so that a simple structure for imaging is provided. The chromatic aberration can be corrected by using the above lens system.

[0009]

According to the present invention, the chromatic aberration can be corrected by changing the optical path length between the imaging lens and the photoelectric conversion unit in accordance with the type of the filter that enters the optical path of the reflected light from the original. The structure of the system can be simplified, and since the photoelectric conversion element is urged by a spring and pressed against the movable body, it can be moved with high accuracy and has the effect that there is no change with time. Things.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a difference between image forming positions of lights having different wavelengths.

FIG. 3 is an explanatory diagram showing a conventional structure for correcting a difference between image forming positions of lights having different wavelengths.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical path 2 Imaging lens 5 Photoelectric conversion part 10 Color separation filter part 10 _B filter 10 _G filter 10 _R filter 13 Spring 14 Arm (movable body)

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Toshiaki Watanabe 10 Ricoh Applied Electronics Research Laboratories, Inc. Microfilm (JP, U) (58) Field of investigation (Int. Cl. ⁷ , DB name) H04N 1/04- 1/207 G06T 1/00

Claims (1)

(57) [Claims] A light source for irradiating the original with illumination light; an imaging lens for imaging reflected light from the original; a first filter, a second filter, and a second filter for reflecting light from the original ; three
A color separation filter unit that separates into primary colors by the filter of the first filter, the second filter,
In a color scanner including a photoelectric conversion unit that converts the separated light color-separated by the third filter into an electric signal, the first filter, the second filter
And the color separation filter unit having the third filter is disposed on the document side of the imaging lens, and each of the filters of each color of the color separation filter unit is reflected from the document.
Provided so as to independently advance and retreat in a direction perpendicular to the optical path of the light, the light of the reflected light from the document to the movable body and the movable body with the movement of the filter to advance perpendicularly to the optical path
A spring for urging the photoelectric conversion unit so that the photoelectric conversion unit comes into contact with a path in a coaxial direction, and the photoelectric conversion unit is coaxial with the optical path of the reflected light from the document according to the movement of the movable body. An image input apparatus comprising an optical path length changing unit for changing an optical path length between the imaging lens and the photoelectric conversion unit by moving the image forming lens and the photoelectric conversion unit.