JP2000253221A - Color picture reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of step-out in synchronization, to miniaturize a reader and to make high quality by moving a light source means, a plurality of mirrors, a connection lens, a reading means, a slit and a color decomposition means in an auxiliary scanning direction in such a state that the relative position relation is fixed. SOLUTION: The lower face of an original is irradiated with light flux radiated from a light source 6 3 directly or through a reflection shade 7. A part of diffused light flux from an original 3 passes through a slit 15, is made incident on a first mirror 8, is reflected to the right/left of a scanning unit 5 at a prescribed angle and is made incident on a second mirror 9. Light flux which is made incident on the second mirror 9 is reflected to the right/left of the integrated scanning optical unit 5 at the prescribed angle. It crosses an optical path L1 between the original 3 and the first mirror 8 and it passes through it. Then, light flux is made incident on a third mirror 10 arranged on the right end side of the scanning unit 5. A subscanning direction is read by the movement of the scanning unit 5 and the relative position relation of the optical elements is kept constant while the subscanning direction is read.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image reading apparatus, and more particularly to an integrated scanning optical system unit which integrally houses a light source means, a slit, a plurality of mirrors, an imaging lens, a color separation means, and a reading means. More particularly, the present invention relates to a color image reading apparatus which reads color image information of a document by using a flatbed image scanner or a digital copying machine.

[0002]

2. Description of the Related Art Conventionally, color image information on a document surface is imaged on a line sensor (CCD) surface via an optical system, and color image information is converted using an output signal from the line sensor at this time. Various digital reading devices have been proposed.

For example, FIG. 6 is a schematic view of a main part of an optical system of a conventional color image reading apparatus. In the figure, when a light beam from a color image on a document surface 61 is condensed by an imaging lens 62 and is imaged on a line sensor surface described later, the light beam is, for example, red (R) and green through a 3P prism 63. (G) and blue (B) after being separated into three colors.
Light is guided on 4, 65, 66 surfaces. Then, the color images formed on the surfaces of the line sensors 64, 65 and 66 are line-scanned in the sub-scanning direction, and reading is performed for each color light.

FIG. 7 is a schematic view of a main part of an optical system of a conventional color image reading apparatus. In the figure, when a light beam from a color image on a document surface 61 is condensed by an imaging lens 62 and formed on a line sensor surface described later, a wavelength selective transmission film having dichroism is added to the light beam. The light is separated into three color lights corresponding to three colors of R, G and B via two beam splitters 74 and 75 for color separation.

A color image based on the three color lights is formed on a so-called monolithic three-line sensor 73 provided with three line sensors on the same substrate surface. Thus, the color image is line-scanned in the sub-scanning direction, and reading is performed for each color light.

FIG. 8 is an explanatory view of the monolithic three-line sensor 73 shown in FIG. 7. The monolithic three-line sensor 73 has three line sensors (CCD) 81, 82, 83 parallel to each other as shown in FIG. Are arranged at a finite distance from each other on the same substrate surface, and a color filter (not shown) based on each color light is provided on the line sensor surface.

The distances S ₁ , S ₂ between the line sensors 81, 82, 83 are generally manufactured to be, for example, about 0.064 to 0.2 mm due to various manufacturing conditions. The pixel widths W1 and W2 of 84 are, for example, 8 μm × 8 μm.
m, about 10 μm × 10 μm.

As shown in FIG. 9, the distances S ₁ and S ₂ between the other two lines 81 and 83 with respect to the center line 82 of the monolithic three-line sensor are generally equal in opposite directions, and Pixel size in the sub-scanning direction (FIG. 8
(Refer to) W2. This is for the following reasons.

That is, as shown in FIG. 9, when reading a color image with the above-described monolithic three-line sensor using only the normal imaging optical system 62, the three line sensors 81, 82, 83 simultaneously operate. Original surface 6 that can be read
The three reading positions 81 are different from each other as shown in FIG.
', 82', and 83 '.

Therefore, the signal components of three colors (R, G, B) at an arbitrary position on the document surface 61 cannot be read at the same time. Come up.

To this end, the distances S ₁ and S ₂ between each line of the three-line sensor are set to be an integral multiple of each pixel size W2, and a redundant line memory is provided in accordance with the distances. By delaying each of the G and R signals (signal components based on the G and R color lights) with respect to the (signal components based on the B color light), a composite signal component of three colors can be obtained relatively easily.

Therefore, as described above, the distances S ₁ and S ₂ between the other two line sensors 81 and 83 with respect to the center line sensor 82 of the three line sensors are set to be an integral multiple of the pixel size W2 in the sub-scanning direction. It is doing.

As another method, as shown in FIG. 10, a monolithic three-line sensor is read by a reading means (light receiving element).
A transmission type one-dimensional blazed diffraction grating 101 as color separation means is disposed in the imaging optical path away from the exit pupil of the imaging lens (projection lens) 62 in the surface direction of the reading means 73, and transmission diffraction is performed. The color separation is performed using
The one-line color image information is converted to a three-line sensor 73.
By separating and forming an image on the surface in the sub-scanning direction,
A color image reading device for reading the color image information has been proposed.

In the color image reading apparatus shown in FIG. 1, the above-mentioned redundant memory is not required, and the cost can be reduced. On the other hand, the 0th-order diffracted light from a position different from the position where the image is formed by the ordinary image forming lens is used. Line sensor 73
This light beam (off-axis light beam in the sub-scanning direction) because it is incident on the surface
It is necessary to arrange a narrow slit 74 for shielding light from the vicinity of the document surface 61.

As described above, the conventional color image reading apparatus has various reading methods. In any of the reading methods, in order to read the document two-dimensionally, the document is scanned and the document is scanned in the sub-scanning direction. Need to read.

FIG. 5 is a schematic view of a main part of a conventional color image reading apparatus such as a flatbed image scanner or a digital copying machine.

In FIG. 1, a document 103 placed on a platen glass 104 includes a direct light from a light source 106 and a reflection shade 1.
Illuminated from both sides by the reflected light beam through the reference numeral 07. The light beam from the document 103 passes through a slit 115 that regulates an off-axis light beam in the sub-scanning direction, and a first mirror 108 for scanning,
The light is guided by the imaging lens 113 via the second mirror 109 and the third mirror 110, and the one-dimensional blazed diffraction grating 1
After color separation into three color lights (B, G, and R) via the optical disc 16, the three color lights are imaged on corresponding image sensor surfaces such as CCDs, and converted into electric signals according to the density of the document 103. The converted image information is read for one line in the main scanning direction (the direction perpendicular to the plane of FIG. 5). To read an image in the sub-scanning direction (in the direction of arrow C in FIG. 5), the first mirror table including the light source 106, the reflection shade 107 and the first mirror 108 is moved in the sub-scanning direction with respect to the document 103, and the second By moving the second mirror base including the mirror 109 and the third mirror 110 in the same direction at half the speed of the first mirror base, the optical path length from the original 103 to the image sensor 114 is kept constant, Color image information is read.

This type of scanning optical system is known as a so-called 1: 2 scanning optical system, and has the advantage that the apparatus size in the sub-scanning direction can be reduced even when the optical path length from the original to the image sensor is increased. is there.

[0019]

However, in the above-described conventional color image reading apparatus using the 1: 2 scanning optical system, the image forming lens 1 fixed to the surface of the document 103 is required.
13, a one-dimensional blazed diffraction grating 116, a reading unit 114 composed of an image sensor, and three scanning mirrors 108, 109, and 11, which are first, second, and third mirrors.
Since it is necessary to scan the surface of the document 103 in the sub-scanning direction by changing the relative positional relationship with respect to the scanning mirrors 108 and 10
Due to the angle error, surface accuracy error, vibration, and the like of 9, 110, uneven density, out of focus, and out of color may occur. In particular, if the relative angle error between the second and third mirrors 109 and 110 is large, the reading position shifts in the sub-scanning direction at the same time as the scanning in the sub-scanning direction, so-called out-of-synchronization occurs. As a result, there is a problem that the read image quality is deteriorated. In order to solve this problem, it is necessary to extremely increase the component accuracy, drive accuracy, and the like of the scanning mirror. As a result, there has been a problem that the size of the entire apparatus is increased and the cost is increased.

The present invention provides a light source means, a slit, a plurality of mirrors, an imaging lens, a one-dimensional blazed diffraction grating, and
The line image sensor reads the color image information of the document by moving in the sub-scanning direction integrally with the relative positional relationship being fixed, thereby suppressing the synchronization shift occurring when reading the document in the sub-scanning direction, An object of the present invention is to provide a small-sized color image reading apparatus capable of preventing a slit kick and obtaining a high-quality color image.

[0021]

According to the present invention, there is provided a color image reading apparatus comprising: (1-1) light source means for illuminating a document; a plurality of mirrors for reflecting a light beam from the document illuminated by the light source means; An image forming lens for forming an image of the light beam reflected by the mirror, reading means arranged at an image forming position of the image forming lens, a slit for regulating an off-axis light beam in the sub-scanning direction arranged near the document, and In a color image reading apparatus having color separation means for separating an incident light beam into a plurality of color lights arranged in an optical path between a document and the reading means, the light source means, the plurality of mirrors, the imaging lens, The reading means, the slit, and the color separation means read color image information of the document by moving in the sub-scanning direction with their relative positional relationship fixed.

In particular, (1-1-1) said light source means, said plurality of mirrors, said imaging lens, said reading means, said slit,
The color separation means is fixed to the same member, and these elements constitute an integrated scanning optical system unit. (1-1-2) The integrated scanning optical system unit includes the slit and the reading unit. Having an adjusting mechanism for adjusting the relative position with respect to the means, or (1-1-3) the adjusting mechanism is capable of moving the slit or / and the reading means in the sub-scanning direction, And that the relative position between the slit and the reading unit is adjusted, or (1-1-4) the color separation unit is disposed in an optical path between the imaging lens and the reading unit. (1-1-5) that the color separation means is provided on a reflection surface of at least one of the plurality of mirrors, and (1-1-6) that the color separation means is transparent. A one-dimensional blazed diffraction grating, (1-1-7)
The color separation means comprises a reflection type one-dimensional blazed diffraction grating.

[0023]

(Embodiment 1) FIG. 1 is a schematic view of a main part of a color image reading apparatus according to a first embodiment of the present invention, and FIG. 2 is a schematic view of a main part of an integrated scanning optical system unit shown in FIG. FIG.

In FIG. 1, reference numeral 1 denotes a main body of the image reading apparatus, and reference numeral 2 denotes a document pressing plate, which presses a document (image) 3. Reference numeral 4 denotes a platen glass on which a document is placed.

Reference numeral 5 denotes an integrated scanning optical system unit which integrally accommodates a light source means, a slit, a plurality of mirrors, an image forming lens, a color separation means, a reading means and the like fixed to the same member. The color image information of the original 3 is read by scanning in the sub-scanning direction (the direction of arrow A in FIG. 1) in a state where the relative positional relationship between the above-described elements is fixed by a driving device (not shown) such as a motor. Note that the integrated scanning optical system unit is also simply referred to as “scanning unit” below.

Reference numeral 6 denotes a light source, which comprises, for example, a fluorescent lamp or a halogen lamp. Reference numeral 7 denotes a reflection shade which reflects the light beam from the light source 6 and illuminates the original 3 efficiently.
Incidentally, the light source 6 and the reflection shade 7 each constitute one element of the light source means. Reference numeral 15 denotes a slit, which has an opening that is long in a direction (main scanning direction) perpendicular to the paper surface of the line image sensor 14, which will be described later, and is arranged near the document 3. The slit 15 prevents the off-axis light beam in the sub-scanning direction from being separated by a one-dimensional blazed diffraction grating as a color separation means described later to prevent predetermined color information from entering a place other than a predetermined line sensor. Crosstalk is suppressed.

Reference numerals 8, 9, 10, 11, and 12 denote first, second, third, fourth, and fifth mirrors, respectively, which are arranged at positions to be described later. I have. Reference numeral 13 denotes an image forming lens which forms a light beam based on image information of the document 3 on a surface of a three-line image sensor 14 as reading means described later. Reference numeral 16 denotes a color separation unit, which is formed of a transmission type one-dimensional blazed diffraction grating, is provided in an optical path between the imaging lens 13 and the reading unit 14, and is based on color image information from the imaging lens 13. The luminous flux is divided into, for example, three color lights R (red), G (green), B
(Blue). Reference numeral 14 denotes a reading means, which is a so-called monolithic three-line image sensor in which three line sensors (CCD) are arranged on the same substrate surface so as to be parallel to each other in the main scanning direction.

In this embodiment, the first, second, third, fourth and fourth
Light connecting the fifth mirror 12, the imaging lens 13, and the three-line image sensor 14, which are optically disposed closest to the entrance surface S1 of the imaging lens 13 among the fifth mirrors 8, 9, 10, 11, and 12 The axis (optical path) L3 is substantially parallel to the surface of the original 3, and the fifth mirror 12, the imaging lens 13, and the three-line image sensor 14 are located at the lowermost position (lower side) of the scanning unit 5 with respect to the original 3 in the drawing. ). Also, of the first, second, third, fourth, and fifth mirrors 8, 9, 10, 11, and 12, the first mirror 8, which is optically closest to the surface of the original 3, is connected to the optical axis L3 and the original 3 In the space between the entrance surface S1 of the imaging lens 13 and the three-line image sensor 14, and the fifth mirror 12
And the three-line image sensor 14 are disposed approximately at the center with respect to the direction along the optical axis. That is, the first mirror 8 is disposed above the imaging lens 13 in the drawing. Fifth
The mirror 12 is arranged so that the incident angle of the light beam on its optical axis is approximately 45 °.

In this embodiment, the light beam emitted from the light source 6 illuminates the lower surface of the document 3 directly or via the reflection shade 7, and a part of the diffuse light beam from the document 3 travels vertically downward in FIG. The light passes through the slit 15 and enters the first mirror 8. The light beam incident on the first mirror 8 is reflected to the left of the scanning unit 5 at a predetermined angle, and is incident on a second mirror 9 disposed on the left end side of the scanning unit 5. Second
The light beam incident on the mirror 9 is scanned at a predetermined angle by the scanning unit 5.
Is reflected to the right, passes through the optical path L1 between the document 3 and the first mirror 8, and then enters the third mirror 10 disposed on the right end side of the scanning unit 5. The light beam incident on the third mirror 10 is reflected in the horizontal direction with respect to the surface of the original 3, passes through the optical path L 1 between the original 3 and the first mirror 8 again, and is disposed on the left end side of the scanning unit 5. Then, the light enters the fourth mirror 11. The light beam incident on the fourth mirror 11 is reflected downward at a right angle to the scanning unit 5, passes through the optical path L <b> 2 between the first mirror 8 and the second mirror 9, and is disposed at the bottom of the scanning unit 5. Then, the light enters the fifth mirror 12. The light beam based on the image information of the document 3 incident on the fifth mirror 12 is reflected in the horizontal direction with respect to the surface of the document 3, and is formed by the imaging lens 13 via the one-dimensional blazed diffraction grating 16 into three color lights (B, G, After the color separation into R), the three color lights are respectively imaged on the corresponding line image sensor surfaces. Then, the scanning unit 5 is driven by a driving device (not shown) such as a motor in the direction of arrow A (sub-scanning direction) shown in FIG.
, The color image information on the three originals is digitally read by the three-line image sensor 14.

In this embodiment, the reading in the sub-scanning direction is performed by moving the scanning unit 5 as described above.
A light source means, a slit 15, a plurality of mirrors 8 for scanning,
9, 10, 11, 12, imaging lens 13, one-dimensional blazed diffraction grating 16, and three-line image sensor 1
The relative positional relationship 4 can be kept constant during reading in the sub-scanning direction, so that even if there is an angular error of the scanning mirror, a slit, or a displacement of the three-line image sensor, even the initial adjustment can be appropriately performed. For example, the problem of the so-called synchronization shift, in which the reading position gradually shifts during the reading in the sub-scanning direction, is eliminated, the occurrence of slit kick can be prevented, and the quality of the read image can be improved.

In this embodiment, the optical path L1 from the document 3 to the first mirror 8 and the optical path (optical axis) L3 from the fifth mirror 12 to the three-line image sensor 14 need not intersect. The distance from 12 to the imaging lens 13 can be shortened, whereby the width of the scanning unit 5 in the sub-scanning direction can be reduced.

Further, since the first mirror 8 is arranged in the space between the entrance surface S1 of the imaging lens 13 and the three-line image sensor 14, the light beam from the light source 6 is directly transmitted to the imaging lens 1
No harmful light such as ghosts and flares can be suppressed.

Since the first mirror 8 is disposed substantially at the center of the scanning unit 5, the document reading position 28 is located substantially at the center of the width of the scanning unit 5 in the sub-scanning direction. When scanning up to the right end, no space is required outside the reading area on the right end side, so that the width of the image reading apparatus in the sub-scanning direction can be well balanced.

Since a mirror having a large width in the main scanning direction such as the first mirror 8 is arranged above the scanning unit 5,
The fifth mirror 12 arranged below can be made smaller, and thereby unnecessary space on both sides of the imaging lens 13 in the main scanning direction can be effectively used.

(Embodiment 2) FIG. 3 shows Embodiment 2 of the present invention.
FIG. 2 is a schematic diagram of a main part of the color image reading device of FIG. In the figure, the same elements as those shown in FIG. 2 are denoted by the same reference numerals.

This embodiment differs from the first embodiment in that an adjusting mechanism for adjusting the relative position between the slit and the three-line image sensor is provided in the integrated scanning optical system unit, and a plurality of scanning mechanisms are provided. That is, four mirrors are provided. Other configurations and optical functions are substantially the same as those of the first embodiment, and the same effects as those of the first embodiment are obtained.

That is, in this embodiment, an adjustment mechanism is provided in the scanning unit 21 to adjust the relative position between the slit 15 and the three-line image sensor 14. This adjustment mechanism sets the slit 15 in the sub-scanning direction (the direction of arrow B in the figure).
The relative position between the slit 15 and the three-line image sensor 14 can be adjusted. In other words, when the reading position on the document surface is displaced due to the angular error of the scanning mirror generated at the time of manufacturing the component, the positional accuracy of the lens and the three-line image sensor, etc., in this embodiment, the slit 15
Is moved in the sub-scanning direction to adjust the relative position between the slit 15 and the three-line image sensor 14. Thereby, the latitude for the slit kick can be increased, and the quality of the read image can be improved.

In this embodiment, the plurality of scanning mirrors are first, second, third, and fourth mirrors 17, 18, 19, and 2.
0, and a fourth mirror disposed optically near the incident surface S1 of the imaging lens 13 among the first, second, third, and fourth mirrors 17, 18, 19, and 20. The optical axis L3 connecting the image pickup lens 20, the imaging lens 13, and the three-line image sensor 14 is substantially parallel to the surface of the original 3, and the fourth mirror 20, the imaging lens 13, and the three-line image sensor 14 The scanning unit 21 is configured to be located at the lowest position (lower position) with respect to the surface of the original 3. Also, first, second, third, and fourth mirrors 17, 18, 19, 2
0, the first mirror 17 which is optically disposed on the document 3 side between the optical axis L3 and the document 3 surface and between the incident surface S1 of the imaging lens 13 and the 3-line image sensor 14 And at substantially the middle with respect to the direction along the optical axis of the fourth mirror 20 and the three-line image sensor 14. The fourth mirror 20 is arranged so that the incident angle of the light beam on its optical axis is approximately 45 °.

In the present embodiment, the light beam emitted from the light source 6 illuminates the lower surface of the document 3 directly or via the reflection shade 7, and a part of the diffuse light beam from the document 3 travels vertically downward in FIG. The first mirror 17 passes through the slit 15
Incident on. The light beam incident on the first mirror 17 is reflected to the right of the scanning unit 21 at a predetermined angle, and is incident on the second mirror 18 disposed at the right end of the scanning unit 21.
The luminous flux incident on the second mirror 18 is reflected in the horizontal direction with respect to the surface of the original 3, passes through the optical path L 1 between the original 3 and the first mirror 17, and is disposed at the left end of the scanning unit 21. Incident on the third mirror 19. The light beam incident on the third mirror 19 is reflected downward at a right angle to the scanning unit 21 and is incident on the fourth mirror 20 disposed at the bottom of the scanning unit 21. The light beam incident on the fourth mirror 20 based on the image information of the original is reflected in the horizontal direction with respect to the three surfaces of the original, and the three color lights (B, G, R) are formed by the imaging lens 13 via the one-dimensional blazed diffraction grating. After color separation into
The three color lights are respectively imaged on the corresponding line image sensor surfaces. Then, by moving the scanning unit 21 in the direction of arrow A (sub-scanning direction) by a driving device (not shown) such as a motor, color image information on the three surfaces of the document is digitally read by the three-line image sensor 14. .

In this embodiment, when adjusting the relative position between the slit 15 and the three-line sensor 14, the slit 15 is moved in the sub-scanning direction. However, the three-line image sensor 14 may be moved. Or slit 14
And the three-line image sensor 15 may be relatively moved.

(Embodiment 3) FIG. 4 shows Embodiment 3 of the present invention.
FIG. 2 is a schematic diagram of a main part of the color image reading device of FIG. In the figure, the same elements as those shown in FIG. 2 are denoted by the same reference numerals.

The present embodiment is different from the first embodiment in that a reflection type one-dimensional blazed diffraction grating is used as color separation means, and the one-dimensional blazed diffraction grating is one of a plurality of mirrors (this embodiment). Then the fourth mirror)
And that a plurality of scanning mirrors are constituted by four mirrors. Other configurations and optical functions are substantially the same as those of the first embodiment, and thus, similar effects are obtained.

That is, in the figure, reference numeral 27 denotes color separation means, which is constituted by a reflection type one-dimensional blazed diffraction grating.
It is provided on the reflection surface of the mirror 26.

In this embodiment, the plurality of scanning mirrors are first, second, third, and fourth mirrors 23, 24, 25, and 2.
6, a second mirror disposed optically near the incident surface S1 of the imaging lens 13 among the first, second, third, and fourth mirrors 23, 24, 25, and 26. The optical axis L4 connecting the imaging lens 13 with the imaging lens 13 and the three-line image sensor 14 is substantially parallel to the surface of the original 3 and the second mirror 2
4 and imaging lens 13 and 3 line image sensor 1
4 is located at the lowest position (lower position) with respect to the surface of the original 3 of the scanning unit 22 in the drawing. Also, of the first, second, third, and fourth mirrors 23, 24, 25, and 26, the first mirror 2 that is optically disposed on the document 3 side.
3 between the optical axis L4 and the surface of the original 3 and the imaging lens 13
Is arranged in the space between the incident surface S1 of the first mirror and the three-line image sensor and substantially in the middle of the second mirror 24 and the three-line image sensor along the optical axis. The second mirror 24 is arranged so that the incident angle of the light beam on its optical axis is approximately 45 °.

In this embodiment, the light beam emitted from the light source 6 illuminates the lower surface of the document 3 directly or via the reflection shade 7, and a part of the diffuse light beam from the document 3 travels vertically downward in FIG. The first mirror 23 passes through the slit 15
Is reflected to the left of the scanning unit 22 at a predetermined angle, and is incident on the second mirror 24 disposed at the left end of the scanning unit 22. The light beam that has entered the second mirror 24 is reflected at a right angle above the scanning unit 22 and enters the third mirror 25 disposed at the left end of the scanning unit 22. The light beam incident on the third mirror 25 is reflected to the right of the scanning unit 22 at a predetermined angle, crosses the optical path L1 between the original 3 and the first mirror 23, and then passes through the right end of the scanning unit 22. The light enters the arranged fourth mirror 26. The luminous flux incident on the fourth mirror 26 passes through a one-dimensional blazed diffraction grating 27 provided on the reflection surface thereof, so that three color lights (B, G,
R), after passing through the optical path L1 between the document 3 and the first mirror 23 again, the third mirror 25
Incident on. Each color light that has entered the third mirror 25 is reflected below the scanning unit 22, and the optical path L2 between the third mirror 25 and the fourth mirror 26 and the optical path L3 between the first mirror 23 and the second mirror 24. And crosses again, and is incident on the second mirror 24 again. Each color light incident on the second mirror 24 is imaged on the corresponding line image sensor surface by the imaging lens 13. Then, by moving the scanning unit 22 in the direction of arrow A (sub-scanning direction) by a driving device (not shown) such as a motor, color image information on the original 3 is digitally read by the three-line image sensor 14. .

In this embodiment, as described above, the reflection type one-dimensional blazed diffraction grating 27 is used as the color separation means, and the one-dimensional blazed diffraction grating 27 is connected to the fourth mirror 26.
The reflection surface can be used as both a reflection mirror and a color separation unit, thereby reducing the number of components and achieving a reduction in the size of the scanning unit 22.

In the present embodiment, the one-dimensional blazed diffraction grating 27 is provided on the reflecting surface of the fourth mirror 26,
The present invention is not limited to this, and may be provided on the reflection surface of another scanning mirror.

[0048]

According to the present invention, as described above, the light source means, the slit, the plurality of mirrors, the image forming lens, the one-dimensional blazed diffraction grating, and the three-line image sensor are integrally formed with their relative positional relations fixed. A color image reading apparatus capable of suppressing color shift occurring when reading a document in the sub-scanning direction and preventing slit kick by reading the color image information of the document by moving the document in the sub-scanning direction. Can be.

According to the present invention, an adjustment mechanism for adjusting the relative position between the slit and the reading means is provided in the integrated scanning optical system unit as described above, and the position of the slit or / and the reading means is adjusted in the sub-scanning direction. By making it possible, it is possible to increase the slit latitude without increasing the precision of the parts, thereby achieving a small-sized, low-cost color image reading apparatus capable of obtaining a high-quality color image.

Further, according to the present invention, the number of components can be reduced by providing the reflection type one-dimensional blazed diffraction grating as the color separation means on the reflection surface of at least one of the plurality of mirrors as described above. Accordingly, it is possible to achieve a color image reading apparatus that can reduce the size of the integrated scanning optical system unit.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of a color image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a main part of the integrated scanning optical system unit shown in FIG. 1;

FIG. 3 is a schematic diagram of a main part of an integrated scanning optical system unit according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram of a main part of an integrated scanning optical system unit according to a third embodiment of the present invention.

FIG. 5 is a schematic view of a main part of a conventional color image reading apparatus.

FIG. 6 is a schematic view of a main part of a conventional color image reading apparatus.

FIG. 7 is a schematic view of a main part of a conventional color image reading apparatus.

FIG. 8 is an explanatory diagram of a monolithic three-line sensor.

FIG. 9 is a schematic view of a main part of a conventional color image reading apparatus.

FIG. 10 is a schematic view of a main part of a conventional color image reading apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 color image reading device 3 document (color image) 4 platen glass 6 light source 7 reflector 5, 21, 22 integrated scanning optical system unit 13 imaging lens 14 reading unit (3-line image sensor) 16, 27 color separation unit (One-dimensional blazed diffraction grating) 8, 9, 10, 11, 12 mirror 17, 18, 19, 20 mirror 23, 24, 25, 26 mirror 15 slit 28 document reading position

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shinichi Arita 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Hidekazu Shimomura 3-30-2 Shimomaruko, Ota-ku, Tokyo Non-corporation F term (reference) 5C072 AA01 BA19 CA02 DA02 DA04 DA10 DA18 DA21 DA23 EA05 LA02 XA01

Claims (8)

[Claims] 1. A light source for illuminating a document, a plurality of mirrors for reflecting a light beam from the document illuminated by the light source, an imaging lens for forming an image of the light reflected by the plurality of mirrors, and the imaging A reading unit arranged at an image forming position of a lens, a slit arranged near the document to regulate an off-axis light beam in the sub-scanning direction, and a plurality of incident light beams arranged in an optical path between the document and the reading unit. A color image reading apparatus having color separation means for performing color separation into the color light, wherein the light source means, the plurality of mirrors, the imaging lens, the reading means, the slit, and the color separation means are arranged in a relative positional relationship. A color image reading apparatus which reads color image information of a document by moving in a sub-scanning direction while being fixed. 2. The light source means, the plurality of mirrors, the imaging lens, the reading means, the slit, and the color separation means are fixed to the same member, and these elements constitute an integrated scanning optical system unit. 2. The color image reading device according to claim 1, wherein 3. The color image reading apparatus according to claim 2, wherein said integrated scanning optical system unit has an adjusting mechanism for adjusting a relative position between said slit and said reading means. 4. The apparatus according to claim 1, wherein the adjusting mechanism adjusts a relative position between the slit and the reading unit by making the slit and / or the reading unit movable in a sub-scanning direction. 4. The color image reading device according to claim 3, wherein: 5. The color image reading device according to claim 1, wherein the color separation unit is disposed in an optical path between the imaging lens and the reading unit. 6. A color image reading apparatus according to claim 1, wherein said color separation means is provided on a reflection surface of at least one of said plurality of mirrors. 7. A color image reading apparatus according to claim 5, wherein said color separation means comprises a transmission type one-dimensional blazed diffraction grating. 8. A color image reading apparatus according to claim 6, wherein said color separation means comprises a reflection type one-dimensional blazed diffraction grating.