JPH08274939A - Color image reader - Google Patents

Abstract

PURPOSE: To prevent the contrast of a read image from lowering by providing a slit used to receive only a required luminous flux only into an optical path in the color image reader. CONSTITUTION: A light from a light source 1 is emitted to an original 6 placed on an original platen 61, a light reflected in a read position 63 is formed by a lens 3 via a reflection mirror 2 and the formed image is read by a photoelectric conversion element 4. Then a case 5 is provided to enclose other than a 1st slit 51 taking the reflected light and the transmitted light from an original face 62 and a 2nd slit 52 is arranged in front close to a lens 3 just before the photoelectric conversion element 4 in the case 5. Thus, even when an undesired light for image reading passes through the 1st slit 51, it is blocked by the 2nd slit 52, resulting that the contrast of the read image is improved in an excellent way to prevent the deterioration in reproducibility of a high density image especially.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides a first slit for arranging a mirror, a lens, a photoelectric conversion element and the like which compose the optical system at prescribed positions and for taking in reflected light and transmitted light from a document surface. By disposing at least one second slit that allows only the necessary light flux to pass in the optical path between the lens and the slit of the housing, in the housing configured to surround the portion other than The present invention relates to a color image reading device in which only necessary light is taken into a lens and an image having high contrast and excellent reproducibility particularly on the high density side can be obtained.

[0002]

2. Description of the Related Art In a conventional first color image reading apparatus, as shown in FIG. 6, a light source O for illuminating an original document D, which is arranged to face an original document table D on which an original document G is placed, transmits reflected light. Reflecting mirrors MA, MB, MC arranged in a case KO having a U-shaped cross section having a slit S for allowing the reflected light to pass through the slit S, and a lens L for forming an image of the reflected light. , And a photoelectric conversion element I for photoelectrically converting the image formed by the lens L is arranged in a case KL having a U-shaped cross section.

In a second conventional color image reading apparatus (Japanese Patent Laid-Open No. 1-2221976), as shown in FIG. 8, a light source O arranged facing a document table D on which a document G is placed has a slit SO. A case K having a square cross section with a slit S for irradiating the original through
Reflecting mirrors MA, MB, MC arranged in P for reflecting the reflected light passing through the slit S, a lens L for focusing the reflected light, and an image formed by the lens L are photoelectrically converted. The photoelectric conversion element I is disposed in a case K having a square cross-section and having a slit S for allowing reflected light to pass therethrough.

[0004]

The above-mentioned first conventional color image reading apparatus uses the image of the light emitted from the light source O and the light reflected and transmitted by the document surface as shown by the thin line in FIG. The light unnecessary for reading reaches the lens L directly or indirectly and causes internal reflection on the lens surface as shown in FIG. 9, which lowers the contrast of the read image and deteriorates reproducibility particularly on the high density side. There was a problem.

The above-mentioned second conventional color image reading apparatus is
Light that is unnecessary for image reading is less than in the conventional first color image reading apparatus, but as shown by the thin line in FIG. 8, the light directly passes through the slit S of the case portion on which the light source O is mounted and other gaps. Alternatively, there is a problem that it reaches the lens L indirectly and causes internal reflection on the lens surface as shown in FIG. 9, which lowers the contrast of the read image and deteriorates reproducibility particularly on the high density side.

Therefore, the inventor of the present invention arranges the mirror, lens, photoelectric conversion element, etc., which compose the optical system, at prescribed positions, and except for the first slit for taking in the reflected light and the transmitted light from the document surface. A technique of the present invention in which at least one second slit that allows only a necessary light flux to pass through is provided in an optical path between the lens and the slit of the housing in the housing configured to surround the portion. As a result of further research and development, the present invention has reached the purpose of preventing the reduction of the contrast of the read image, particularly the deterioration of the reproducibility on the high density side.

[0007]

According to the color image reading apparatus of the present invention (the first invention according to claim 1), the original surface is irradiated with a light source and the reflected light and the transmitted light are photoelectrically transmitted through an optical system. In a color image reading device that converts electric signals to obtain an electric signal, the mirrors, lenses, photoelectric conversion elements, and the like that form the optical system are arranged at prescribed positions, and reflected light and transmitted light from the document surface are arranged. First to be incorporated
A housing configured to surround a portion other than the slit, and at least one second light flux that allows only a necessary light flux to pass through an optical path between the lens and the slit of the housing in the housing. It has a slit.

The color image reading device of the present invention (the second invention according to claim 2) is the same as the second invention in the first invention.
The slit is disposed in front of and close to the lens.

The color image reading apparatus of the present invention (the third invention according to claim 3) is the same as the second invention in the second invention.
The slit includes a slit having a narrower gap than the gap of the first slit arranged near the first slit formed in the housing.

The color image reading apparatus of the present invention (the fourth invention according to claim 4) is the same as the second invention in the third invention.
Is disposed in the vicinity of a mirror that horizontally reflects reflected light reflected vertically downward from the first slit, which is disposed below the first slit formed in the housing. It includes a slit that has been cut.

[0011]

In the color image reading apparatus of the first invention having the above-mentioned structure, the mirror, the lens, the photoelectric conversion element and the like which constitute the optical system are arranged at prescribed positions, and the reflected light and the transmitted light from the document surface are arranged. In a housing configured to surround a portion other than the first slit that receives
Since at least one second slit that allows only the necessary light flux to pass through is arranged in the optical path between the lens and the slit of the housing, light unnecessary for image reading passes through the first slit. However, the passage is blocked by the second slit.

In the color image reading apparatus of the second invention having the above structure, even if the light unnecessary for image reading passes through the first slit, the second image sensor is arranged in front of the lens in proximity to the lens. The slit blocks the passage.

In the color image reading apparatus of the third invention having the above-mentioned structure, even if light unnecessary for image reading passes through the first slit, it comes close to the first slit formed in the housing. Passage is blocked by a slit having a gap narrower than the gap of the first slits arranged as described above.

In the color image reading apparatus of the fourth aspect of the present invention having the above structure, even if light unnecessary for image reading passes through the first slit, the color image reading apparatus is provided below the first slit formed in the housing. The slits that constitute the second slits that are disposed in the vicinity of the mirror that horizontally reflects the reflected light that is reflected vertically downward from the disposed first slits prevent the passage of light. is there.

[0015]

According to the color image reading apparatus of the first aspect of the present invention, which has the above-described operation, at least one second light ray passing only the necessary light beam is allowed to pass through the optical path between the lens in the housing and the slit of the housing. Since the slits are provided, even if unnecessary light for image reading passes through the first slits, the second slits prevent the light from passing therethrough, so that the contrast of the read image is lowered, especially on the high density side. This has the effect of preventing deterioration of reproducibility.

In the color image reading apparatus of the second invention having the above-mentioned operation, even if the light unnecessary for image reading passes through the first slit, the second image sensor is arranged in front of the lens in proximity to the lens. Since the passage is blocked by the slit, it is possible to effectively prevent a reduction in the contrast of the read image, particularly a deterioration in the reproducibility on the high density side.

In the color image reading apparatus according to the third aspect of the present invention which has the above-mentioned operation, even if the light unnecessary for image reading passes through the first slit, the color image reading apparatus approaches the first slit formed in the casing. Since passage is blocked by a slit having a gap narrower than the gap of the first slits arranged as described above, it is possible to more effectively prevent deterioration of the contrast of the read image, particularly deterioration of reproducibility on the high density side. .

In the color image reading device of the fourth invention having the above-mentioned operation, even if light unnecessary for image reading passes through the first slit, the color image reading device is provided below the first slit formed in the casing. Since the slits constituting the second slit arranged in proximity to the mirror that reflects the reflected light reflected vertically downward from the arranged first slit in the horizontal direction block passage, It is possible to more effectively prevent the deterioration of the contrast of the read image, particularly the deterioration of the reproducibility on the high density side.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) As shown in FIG. 1, the color image reading apparatus of the first embodiment includes a light source 1 for irradiating a document 6 placed on a document table 61 with light, and the document 6 described above. A reflection mirror 2 for reflecting the light reflected at the reading position 63;
A lens 3 that forms an image of the light reflected by the reflection mirror 2 and a photoelectric conversion element 4 that reads the formed image and performs photoelectric conversion are arranged at prescribed positions, and a document surface 6 is provided.
A housing 5 configured to surround a portion other than the first slit 51 that takes in the reflected light and the transmitted light from the second slit 2 is provided in the housing 5 in the vicinity of the lens 3 and in the front in the second slit. 52 is provided.

As shown in FIG. 1, the original table 61 is composed of a platen glass which is a transparent and flat plate member which is placed on the upper portion of the apparatus main body 60 and the color original 6 is placed on the lower surface. A document reading position 63 is formed on the upper surface with which the color document 6 abuts.

As shown in FIG. 1, the light source 1 has a rectangular-shaped light source case 53 formed in the center of the upper surface of the housing 5.
Inside, a relatively large gap 511 is formed on the upper surface and a relatively small gap 512 is formed on the lower surface, and the first slit 51 is constituted by both.

As shown in FIG. 1, the reflection mirror 2 is arranged below the reading position 63 and the first slit 51 and is inclined by 45 degrees, and horizontally reflects light reflected vertically downward on the document surface. A first mirror 21 that reflects leftward in the direction, and a second mirror 22 that is disposed to the left of the first mirror 21 and that reflects light to the left in the horizontal direction diagonally to the upper right.
And a third mirror 23 which is arranged to incline to the upper right of the casing 5 and reflects light reflected obliquely to the upper right to the left in the horizontal direction.

As shown in FIG. 1, the lens 3 is vertically arranged on the upper left side of the housing 5, and reflects the light reflected at the reading position 63 into the third mirror 2 of the reflection mirror 2.
The reflected light, which is reflected and supplied to the left in the horizontal direction by 3, is formed into an image on the light receiving surface 40 of the photoelectric conversion element 4.

The second slit 52 is formed in the lens 3
It is coaxially arranged in front of.

The photoelectric conversion element 4 is composed of a CCD image sensor and is driven as shown in FIG.
The light intensity of the image formed on the light receiving surface 40 is sequentially converted into a voltage signal and can be output to an image processing circuit (not shown).

In the color image reading apparatus of the first embodiment having the above-mentioned structure, the light source 1 is arranged in a light source case 53 having a rectangular cross section formed in the central portion of the upper surface of the housing 5, as shown in FIG. Is the first slit 5 formed on the upper surface.
The document 6 placed on the document table 61 is irradiated with light through the relatively large gap 511 forming part 1.

Reflected light reflected at the reading position 63 of the original 6 is relatively large gap 511 forming the first slit 51 formed on the upper surface and relatively small light formed on the lower surface as shown in FIG. It is supplied to the reflection mirror 2 through a small gap 512.

The reflected light that has passed through the first slit 51 is, as shown in FIG. 1, the reading position 63 and the first light.
The light reflected vertically downward on the original surface 62 is reflected to the left in the horizontal direction by the first mirror 21 arranged below the slit 51 of the first mirror 21. The second mirror 22 arranged on the left side of the second mirror 22 reflects the reflected light on the left side in the horizontal direction diagonally to the upper right, and the second mirror 22 is inclined to the upper right of the casing 5. The light reflected obliquely to the upper right by the three-mirror 23 is reflected to the left in the horizontal direction.

The lens 3, which is vertically arranged on the upper left side of the housing, is reflected leftward in the horizontal direction by the third mirror 23 of the reflecting mirror 2 as shown in FIG. The reflected light supplied through the slit 52 is imaged on the light receiving surface 40 of the photoelectric conversion element 4.

The photoelectric conversion element 4 sequentially converts the light intensity of the image formed on the light receiving surface 40 by the light source 1 driven as shown in FIG. 1 into a voltage signal, and an image processing circuit (not shown). Output).

Even if the light unnecessary for image reading passes through the first slit, the second slit 52 disposed in front of and close to the lens 3 as shown by the thin line in FIG.
To prevent passage.

Further, the original 6 irradiated from the light source 1
The reflected light reflected at a point other than the reading position 63 is reflected by the upper surface of the housing 5 as indicated by the thin line in FIG.
Entry into the housing 5 is prevented.

Light unnecessary for image reading that has passed through the first slit 51 is blocked by the second slit 52 disposed in front of and close to the lens 3, so that the conventional device can be used. In addition, the occurrence of internal reflection on the lens surface is prevented.

In the color image reading apparatus of the first embodiment having the above-mentioned operation, the lens 3 in the housing 5 and the housing 5 are provided.
Since the one second slit 52 that allows only the necessary light flux to pass through is disposed in the optical path between the first slit 51 and
Even if light unnecessary for image reading passes through the first slit 51, the second slit 52 prevents the light from passing therethrough, so that the contrast of the read image is prevented from being lowered, especially the reproducibility on the high density side is prevented from being deteriorated. Has the effect of doing.

Further, the color image reading apparatus of the first embodiment is
Even if light unnecessary for image reading passes through the first slit 51, the second slit 52 disposed in front of and close to the lens 3 prevents the light from passing, so that the contrast of the read image is lowered. In particular, the effect of effectively preventing the deterioration of reproducibility on the high concentration side is exhibited.

Further, in the color image reading apparatus of the first embodiment, the reading position 6 of the original 6 irradiated by the light source 1 is read.
The reflected light reflected at points other than 3 is reflected by the upper surface of the housing 5 as shown by the thin line in FIG. 2 and has the effect of being prevented from entering the housing 5.

Further, the color image reading apparatus of the first embodiment is
Light that has passed through the first slit 51 and is unnecessary for image reading is blocked by the second slit 52 disposed in front of and in close proximity to the lens 3, so that the lens does not have to be mounted as in the conventional device. There is an effect that the occurrence of internal reflection on the surface is prevented.

(Second Embodiment) As shown in FIG. 4, the color image reading apparatus of the second embodiment has the first slit formed on the housing in addition to the second slit 52 of the first embodiment. The third slit 54 having a gap narrower than the gap of the first slit arranged in the vicinity of the first slit and the first slit 51 formed in the housing 5 The fourth slit 55 is provided in the vicinity of the first mirror 21 that horizontally reflects the reflected light reflected vertically downward from the first slit 51.

In the color image reading apparatus of the second embodiment having the above-mentioned structure, the first slit formed in the casing 5 is formed even if light unnecessary for image reading passes through the first slit 51. The passage is blocked by a third slit 54 having a gap narrower than the gap of the first slit 51 arranged close to 51.

The color image reading apparatus of the second embodiment is
Even if light unnecessary for image reading passes through the first slit 51, the light is vertically downward from the first slit 51 provided below the first slit 51 formed in the housing 5. Mirror 2 that reflects the reflected light in the horizontal direction
The passage is blocked by the fourth slit 55 arranged in proximity to 1.

In the color image reading apparatus of the second embodiment having the above-described operation, even if light unnecessary for image reading passes through the first slit 51, the first slit formed in the casing 5 is used. Since the passage is blocked by the third slit 54 having a gap narrower than the gap of the first slit 51 arranged close to 51, the contrast of the read image is deteriorated, especially the reproducibility on the high density side is deteriorated. This has the effect of preventing it more effectively.

The color image reading apparatus of the second embodiment is
Even if light unnecessary for image reading passes through the first slit 51, the light is vertically downward from the first slit 51 provided below the first slit 51 formed in the housing 5. Mirror 2 that reflects the reflected light in the horizontal direction
Since the passage is blocked by the fourth slit 55 disposed in proximity to 1, there is an effect that the deterioration of the contrast of the read image, particularly the deterioration of the reproducibility on the high density side is prevented more effectively.

Further, in the color image reading apparatus of the second embodiment, in order to pass only the necessary luminous flux in the optical path between the lens 3 in the housing 5 and the first slit 51 of the housing 5, The second to fourth slits 52, 54, 5
Since 5 is provided, the light unnecessary for image reading is
Even if it passes through the slit 51, the second to fourth slits 52, 54, 55 surely prevent the passage, so that the contrast of the read image is prevented from being lowered, and as shown in FIG. This has the effect of preventing deterioration of reproducibility on the high density side as compared with the apparatus.

The embodiments described above are merely examples for the purpose of explanation, and the present invention is not limited to them. Those skilled in the art will recognize from the claims, the detailed description of the invention and the description of the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment device of the present invention.

FIG. 2 is a cross-sectional view illustrating a state in which unnecessary light is blocked by the device according to the first embodiment.

FIG. 3 is an explanatory diagram for explaining a mechanism for preventing internal reflection in the lens of the device of the first embodiment.

FIG. 4 is a cross-sectional view showing a second embodiment device of the present invention.

FIG. 5 is a diagram comparing the reproducibility of the device of the second embodiment and the conventional device.

FIG. 6 is a cross-sectional view showing a conventional first device.

FIG. 7 is a cross-sectional view showing a reflection mode of unnecessary light in the first conventional device.

FIG. 8 is a cross-sectional view showing a conventional second device.

FIG. 9 is an explanatory diagram showing a mechanism of internal lens reflection in the first and second conventional devices.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 light source 2 reflection mirror 3 lens 4 photoelectric conversion element 5 housing 6 document 51 first slit 52 second slit 61 document table 62 document surface 63 reading position

Claims (4)

[Claims] 1. A color image reading apparatus which irradiates an original surface with a light source and photoelectrically converts reflected light and transmitted light through an optical system to obtain an electric signal, wherein a mirror constituting the optical system, A lens, a photoelectric conversion element, and the like are arranged at prescribed positions, and a housing is provided so as to surround a portion other than the first slit that receives the reflected light and the transmitted light from the document surface. In the color image reading apparatus, at least one second slit is arranged in the optical path between the lens and the slit of the housing to allow only a necessary light beam to pass therethrough. 2. The color image reading device according to claim 1, wherein the second slit is arranged in front of and in proximity to the lens. 3. The first slit according to claim 2, wherein the second slit is formed in the housing.
A slit having a gap narrower than the gap of the first slit arranged near the slit. 4. The first slit according to claim 3, wherein the second slit is formed in the housing.
Color image including a slit disposed in the vicinity of a mirror that horizontally reflects reflected light reflected vertically downward from the first slit disposed below the slit. Reader.