JPH09298629A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the configuration of the image reader by adopting an integrally fixed structure for a stationary optical system with a zoom function, a color separation prism and a solid-state image pickup element without the use of a position adjustment mechanism. SOLUTION: An optical system 44 includes an automatic zoom mechanism, an automatic iris mechanism, an automatic focus mechanism and an ND filter rocking mechanism, forms surely an image with high accuracy even when the magnification is changed and adjusts the highlight/shadow density effectively. A read section 46 is placed on an optical path of a light L and has three color separation prisms 116a-116c fixed integrally with the optical system 44 and three CCDs (solid-state image pickup elements) 118a-118c fixed integrally with the three color separation prisms 116a-116c. The color separation prisms 116a-116c separate the light L reflected in a read original 24 into three primary colors R, G, B and lead them to the CCDs 118a-118c. Thus, the structure of the optical system and the read section is simplified at once to reduce the manufacture cost of the entire reader.

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 for photoelectrically reading light containing image information carried on a read original.

[0002]

2. Description of the Related Art For example, in a plane scanning type image reading apparatus,
By irradiating the reading document placed on the document table with illumination light, the light containing the image information carried on the reading document is guided to the condensing optical system as reflected light or transmitted light,
It is configured to read photoelectrically with a solid-state imaging device such as a CCD.

An image reading apparatus of this type usually has a position adjusting mechanism for a condensing optical system and a position adjusting mechanism for a solid-state image pickup device in response to a request for correction of mechanical or optical error or change of magnification. Prepared individually.

[0004]

However, in the above-mentioned image reading apparatus, the focusing optical system and the solid-state image pickup device are provided with their own position adjusting mechanisms. Therefore, it has been pointed out that the structure of the entire image reading apparatus becomes complicated and the manufacturing cost of the image reading apparatus rises considerably.

The present invention solves this kind of problem, and provides an image reading apparatus capable of reading the image information carried on the read original with high accuracy with a simple and inexpensive structure. To aim.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention contemplates that light containing image information carried on a read document is focused on a reading unit via a fixed optical system with a zoom mechanism. In addition, the reading unit has a color separation prism that is integrally fixed to the optical system and a solid-state image sensor that is integrally fixed to the color separation prism.

Therefore, the optical system, the color separation prism, and the solid-state image pickup element are integrally fixed to each other without using the position adjusting mechanism, and the structure of the entire apparatus is simplified. At this time, since the optical system has the autofocus mechanism, it is possible to form the light including the image information on the solid-state image sensor with high accuracy and reliability.

Further, the optical system is provided with an ND filter capable of swinging. Therefore, it becomes possible to effectively adjust the highlight density or shadow density of the reflected light or the transmitted light from the read document.

Furthermore, the frame section separately provides a first accommodating section for arranging the illumination section, the optical system and the reading section, and a second accommodating section for arranging the control section including the power source and the board section. . As a result, the first accommodating portion and the second accommodating portion perform their respective operations individually, and particularly the illuminating portion, the optical system, and the reading portion can be easily adjusted, and the workability is effectively improved.

[0010]

1 is a perspective view of an image reading device 10 according to an embodiment of the present invention, and FIG. 2 is a schematic perspective view of the inside of the image reading device 10 with a part thereof cut away. Three
FIG. 3 is an internal schematic configuration diagram of the image reading device 10.

The image reading apparatus 10 has a frame portion 14 covered with a cover 12, and the frame portion 14 is provided with a first accommodating portion 16 and a second accommodating portion 18 separately on the upper and lower sides. A reference seat 20 is provided on the upper portion of the frame portion 14, and a document placing table 22 is arranged on the reference seat 20 so as to be openable and closable.

A reflection type reading document 2 is placed on the document table 22.
4 (or a transmissive reading original 24a described later) on which a transparent glass plate 26 is placed, and a chart plate 2 for autofocusing according to the size of the reading original 24.
8 and a glass plate 31 on which a shading reference plate 30 for performing shading correction is mounted, and an original pressing plate 32 is swingably arranged on the glass plate 26. The chart plate 28 includes, for example,
An inspection pattern (not shown) corresponding to the sizes A5 to B3 (+ α) is formed, and the shading reference plate 30 is a white plate.

In order to obtain the light L containing the image information carried by the read document 24, the read document 2 is stored in the first accommodating portion 16.
And an illumination unit 40 that illuminates the illumination light La to
Moving mechanism 42 for moving 0 in the sub-scanning direction (direction of arrow A in FIGS. 2 and 3), and fixed with zoom mechanism for condensing light L containing the image information obtained via the illumination unit 40. The mold optical system 44 and the reading unit 46 for photoelectrically reading the image information contained in the light L condensed by the optical system 44.
And are arranged.

The illumination section 40 includes a light source unit 48 and a reflecting mirror unit 50. The light source unit 48 is provided on the first end side (front side) of the frame portion 14 in the lateral direction.
A bracket 52 is provided, and two halogen lamps 54a and 54b are provided on the first bracket 52, and
It is removably attached from the front side.

Reflecting mirror blocks 56a and 56b for deflecting the light paths of the halogen lamps 54a and 54b by 90 ° are arranged on the illuminating light irradiating side of the halogen lamps 54a and 54b. Quartz rods 58a and 58b extending in the scanning direction (arrow B direction) are provided. Below the quartz rods 58a and 58b, a reflecting mirror 60 for changing the optical path of the light L reflected by the read document 24 from the vertical direction to the horizontal direction is provided.

The reflecting mirror unit 50 has two reflecting mirrors 62a and 62b for changing the optical path of the light L reflected by the reflecting mirror 60 in the horizontal direction to guide it to the optical system 44. The reflecting mirrors 62a and 62b extend in the direction of arrow B and are attached to the second bracket 64.

The moving mechanism 42 has a carrying motor 66, and a rotary shaft 67 is connected to the drive shaft side of the carrying motor 66. As shown in FIG. 4, a first cord-shaped body 68 and a second cord-shaped body 69 are wound around the rotating shaft 67. One end sides 68a, 69a of the first and second string-like bodies 68, 69 are supported by a pair of guide bars 70a, 70b extending in the direction of arrow A, and the tubular guide portion 7 of the light source unit 48 that can move back and forth.
1a and 71b, and then pulleys 73a mounted on the cylindrical guide portions 72a and 72b of the reflecting mirror unit 50,
73b is engaged, folded back, and fixed to the frame portion 14.

The other ends 68b and 69b of the first and second cord-like bodies 68 and 69 are engaged with the pulleys 73c and 73d supported at the lateral ends of the frame portion 14 and folded back to form a tubular guide portion. After being further folded back by the pulleys 73a and 73b of 72a and 72b, they are guided by the pulleys 73e and 73f, and the tension springs 75 are fixed to both ends.

As shown in FIG. 5, the optical system 44 includes a lens group 74 including a zoom lens, and an auto-zoom mechanism 76, an auto-iris mechanism 78 and an auto-focus mechanism 80 are provided on the optical path of the lens group 74. To be
An ND filter 82 is provided in front of the lens group 74 so as to be arranged on the optical path of the lens group 74 and outside the optical path via a swing mechanism 84 (see FIGS. 5 and 6).

The automatic zoom mechanism 76 includes a first pulse motor 86, and a rotary shaft 88 of the first pulse motor 86.
The magnification changing ring 94 meshes with the first gear 90 fixed to the first gear 90 via the first idle gear 92. The auto-iris mechanism 78 and the auto-focus mechanism 80 include second and third pulse motors 96 and 98, and second and third gears fixed to rotary shafts 100 and 102 of the second and third pulse motors 96 and 98. A diaphragm changing ring 112 and a focus changing ring 114 mesh with 104 and 106 via second and third idle gears 108 and 110, respectively. The autofocus mechanism 80 adjusts the focus by changing the distance between the lens group 74 and the reading unit 46 by rotating the focus changing ring 114.

As shown in FIG. 3, the reading section 46 includes three color separation prisms 116a to 116c arranged on the optical path of the light L and integrally fixed to the optical system 44, and the color separation prisms 116a to 116c. A plurality of CCDs (solid-state image pickup devices) 118a to 118c integrally fixed to the color separation prisms 116a to 116c for photoelectrically reading image information contained in each color of light obtained by the image pickup device 116c. The color separation prisms 116a to 116c are used for the read original 2
The light L reflected from the light source 4 is split into three primary colors of R, G, and B and guided to the CCDs 118a to 118c.

As shown in FIG. 6, the ND filter 82 is
It has a substantially rectangular shape that is long in the direction of arrow B, and is fixed to the support member 120 that constitutes a link. Swing mechanism 84
Includes a motor 122, and the drive shaft 1 of the motor 122.
One end of the first swing arm 126 is fixed to the first swing arm 126, and the support member 120 is attached to the other end of the first swing arm 126.
One end of is engaged. A second swing arm 130 is engaged with the other end of the support member 120, and the second swing arm 130 is swingably arranged via a fulcrum 132.

The first swing arm 126 is provided with a spring (not shown) that constantly urges the ND filter 82 in the direction of arrow C in order to retract it from the optical path. A sensor 134 for detecting the position of the ND filter 82 based on the swing angle of the second swing arm 130 is mounted on the second swing arm 130 side.

As shown in FIGS. 2 and 7, the cooling mechanism 140 is disposed in the first housing portion 16 on the front surface side of the frame portion 14 via a plurality of rubber members 142 which are earthquake-proof members. . The cooling mechanism 140 is rotated via the motors 144 and 146, and includes cylindrical members 148 and 150 that are elongated in the arrow A direction.

As shown in FIGS. 2 and 3, the second accommodating portion 18 is provided with a power source 160 and a control portion 162. The control unit 162 includes a lighting unit 40, a moving mechanism 42,
Various substrates 164a to 164n for driving and controlling the optical system 44 and the reading unit 46 are provided. For example, the CCDs 118 a to 118 c forming the reading unit 46 are connected to the substrate 164 b via the flexible cable 166.

A transmissive illumination unit 170 for reading the transmissive read original 24a can be attached to the image reading apparatus 10. As shown in FIGS. 1, 8 and 9,
The transillumination unit 170 includes a main body unit 172 directly arranged on the document placing table 22 from which the document pressing plate 32 is removed.

The main body 172 is elongated in the sub-scanning direction (the direction of arrow A), and a conveying motor 174 is attached to one end inside thereof. A drive pulley 178 is rotatably mounted on a drive shaft 176 extending upward from the transport motor 174. The drive belt 178 and a driven pulley 180 disposed at the other inner end of the main body 172 are attached to the transport belt 182.
Is installed.

The conveyor belt 182 has a movable casing 1
84 is fixed. The moving casing 184 is configured to be long in the main scanning direction (direction of arrow B), has a plurality of rollers 186 that roll on the document table 22, and has a halogen light source as a light source on one end side thereof. The lamp 188 is mounted. On the illumination light irradiation side of the halogen lamp 188, a reflector block 19 for deflecting the optical path by 90 ° is provided.
0 is arranged, and a quartz rod 192 extending in the main scanning direction is provided on the illumination light lead-out side of the reflecting mirror block 190. A cooling fan 194 for cooling the halogen lamp 188 is provided in the moving casing 184.

The operation of the image reading apparatus 10 thus constructed will be described below.

First, in the optical system 44, various adjustment work is appropriately performed every time the image reading apparatus 10 is started, or every predetermined time. For example, when changing the magnification, when
As shown in, the first pulse motor 86 that constitutes the automatic zoom mechanism 76 is driven, and the magnification changing ring 94 is rotated to a predetermined angle via the first gear 90 and the first idle gear 92.

On the other hand, when performing shading correction,
After the light source unit 48 that constitutes the illumination section 40 is arranged below the shading reference plate 30, the halogen lamp 5
4a and 54b are driven to illuminate the shading reference plate 30 with the illumination light La from the quartz rods 58a and 58b.

The light L reflected from the shading reference plate 30 is reflected from the reflecting mirror 60 by the two reflecting mirrors 62a and 62b constituting the reflecting mirror unit 50, and the optical system 44 is shown.
From each CC via color separation prisms 116a to 116c
It is led to D118a to 118c. Each CCD 118a-
118 c photoelectrically converts the reflected light L into R, G, and B signals, respectively, and converts them into the flexible cable 16
It leads to the board | substrate 164b via 6.

Further, the ND filter 82 is provided with the swing mechanism 8
Under the driving action of the motor 122 constituting the fourth lens unit 4, the light L is arranged integrally with the support member 120 from the outside of the optical path of the light L via the first swing arm 126 and the second swing arm 130. Therefore, the light L reflected by the shading reference plate 30 passes through the ND filter 82 and is transmitted to each of the CCDs 118a to 118a.
The R, G, and B signals introduced into 118c and subjected to photoelectric conversion are guided to the substrate 164b. As a result, the optical system 44
Shading correction due to the characteristics of the CCDs 118a to 118c is performed.

When autofocusing is performed according to the size of the read document 24, the halogen lamps 54a and 54b are operated under the action of the light source unit 48 that constitutes the illumination section 40.
Is driven to illuminate the chart plate 28 with the illumination light La from the quartz rods 58a and 58b. An inspection pattern corresponding to the size of A5 to B3 (+ α) is previously formed on the chart plate 28, and the light L reflected from the predetermined inspection pattern is passed through the color separation prisms 116a to 116c to the CCDs 118a to 118c. Is imaged.

Then, under the driving action of the third pulse motor 98 constituting the autofocus mechanism 80, the focus changing ring 114 is rotated to a predetermined angle to perform the focus adjusting work. It should be noted that it is desirable to perform the above-mentioned auto-focusing every predetermined time because the focus position is likely to be displaced due to the humidity change in the image reading apparatus 10.

Furthermore, when adjusting the aperture, the second pulse motor 96 constituting the auto iris mechanism 78 is driven and the aperture changing ring 112 is rotated to automatically perform the aperture adjusting work. It

Therefore, when the image information carried on the read document 24 is read, first, with the document pressing plate 32 being opened upward, this reading is performed on the glass plate 26 constituting the document placing table 22. The document 24 is placed with the reading surface facing down. Further, by closing the document pressing plate 32, the read document 24 is placed in close contact with the glass plate 26.

Next, the halogen lamps 54a and 54b in the light source unit 48 constituting the illumination section 40 are energized and the moving mechanism 42 is driven. The illumination light La emitted from the halogen lamps 54a and 54b is deflected by 90 ° by the reflecting mirror blocks 56a and 56b and guided to the quartz rods 58a and 58b.
The reading surface of the read document 24 is irradiated from 8b through the glass plate 26. The light L reflected by the read document 24 passes through the glass plate 26 and reaches the reflecting mirror 60.
After the optical path is changed from vertical to horizontal by
The light is reflected by the reflecting mirrors 62 a and 62 b in the reflecting mirror unit 50 and guided to the optical system 44.

The light L guided to the optical system 44 is condensed by a lens group 74 including a zoom lens, and then separated into three primary colors of R, G and B by color separation prisms 116a to 116c, respectively CCD 118a to. Irradiation is performed on the light receiving surface of 118c. The image information projected onto the light-receiving surfaces of the CCDs 118a to 118c is converted into an electric signal and then transmitted through the flexible cable 166 to the substrate 164b.
Sent to

On the other hand, when the carrying motor 66 constituting the moving mechanism 42 is driven, the rotary shaft 67 is rotated and both ends 68a, 68b, 6 of the first and second cord-like bodies 68, 69 are rotated.
9a and 69b move in different directions (see FIG. 4).
Middle, see arrow). Therefore, the light source unit 48 and the reflecting mirror unit 50 do not change the optical path length between the read document 24 and the optical system 44, that is, the reflecting mirror unit 50 is half the moving distance of the light source unit 48. The sub-scan feed is carried out in the direction of arrow A.

By the above operation, the light source unit 48 and the reflecting mirror unit 50 are moved from the position shown by the solid line to the position shown by the broken line in FIG. 3, so that all the image information carried on the read document 24 is read.

In this case, in this embodiment, the optical system 44 for condensing the light L containing the image information obtained from the read document 24 via the illumination unit 40 is fixed, and this optical system 44 is fixed. Color separation prism 116 that constitutes the reading unit 46
a-116c and CCDs 118a-118c are integrally fixed. For this reason, conventionally, the optical system 44 and the reading unit 4 are provided with dedicated position adjusting mechanisms.
The configuration of 6 is simplified, and the manufacturing cost of the entire image reading apparatus 10 incorporating the optical system 44 and the reading unit 46 is significantly reduced.

Further, the optical system 44 is provided with an auto focus mechanism 80 in addition to the auto zoom mechanism 76 and the auto iris mechanism 78. Therefore, the light L including the image information reflected from the read document 24 is reflected by each of the CCDs 118a-1.
It is possible to accurately and reliably form an image on 18c and obtain high-quality image information. Moreover, heat sources such as halogen lamps 54a and 54b are provided in the image reading apparatus 10, and the humidity in the image reading apparatus 10 is likely to fluctuate greatly. For example, the autofocus mechanism 8 is provided every predetermined time.
By driving 0, it becomes possible to effectively prevent the shift of the focal position.

Furthermore, the frame portion 14 is provided with the first and second accommodating portions 16 and 18 individually on the upper and lower sides, and in the upper first accommodating portion 16, the illuminating portion which is an optical component and a mechanical component. 40, a moving mechanism 42, an optical system 44, and a reading section 46 are arranged, while the second accommodating section 18 below this is arranged.
Include a power supply 160 and various boards 164a-164n.
A control unit 162 including is arranged.

As a result, the first accommodating portion 16 and the second accommodating portion 18 can be individually operated, and in particular, the illuminating portion 40 and the optical system 44 arranged in the first accommodating portion 16 can be operated. Also, there is an advantage that adjustment work of various optical components in the reading unit 46 can be easily and surely performed and workability is improved at once.

By the way, in the image reading apparatus 10 according to the present embodiment, it is possible to perform the reading operation of the transmissive read original 24a in addition to the read original 24 which is the reflective original. That is, in FIG. 1, the document holding plate 32 is attached to the document placing table 22.
Then, the transillumination unit 170 is placed on the original placing table 22. Further, as shown in FIG. 9, a read original 24 a is placed on the glass plate 26 of the original placing table 22, and the read original 24 a is brought into close contact with the glass plate 26 by the original pressing plate 196.

Next, the halogen lamp 188 is energized so that the illumination light La is emitted from the reflecting mirror block 190 to the quartz rod 1.
The reading light 24 a is guided to the reading document 24 a on the document table 22 via the quartz rod 192, and the illumination light La is applied to the reading document 24 a. At that time, the transportation motor 174 is drive-controlled in synchronization with the transportation motor 66 that constitutes the moving mechanism 42. For this reason, the moving casing 184 is mounted via the transport belt 182 stretched between the drive pulley 178 fixed to the drive shaft 176 of the transport motor 174 and the driven pulley 180.
Is conveyed in the direction of arrow A, and the first bracket 52 is conveyed integrally with the moving casing 184 in the direction of arrow A (see FIG. 9).

Therefore, the illumination light La emitted from the quartz rod 192 is emitted from the original holding plate 196 and the read original 24.
After passing through a, the light is guided to the reflecting mirror 60 in the first bracket 52, and then from the reflecting mirror 60 to the optical system 44 via the reflecting mirrors 62a and 62b in the reflecting mirror unit 50.
As a result, when the moving casing 184 is conveyed in the direction of arrow A and is moved from the position indicated by the solid line to the position indicated by the alternate long and two short dashes line in FIG. 7, all the image information carried on the read document 24a can be read. become.

[0049]

As described above, in the image reading apparatus according to the present invention, the color separation that constitutes the reading unit is provided in the fixed type optical system with the zoom mechanism that collects the light including the image information carried on the read document. The prism and the solid-state image sensor are integrally fixed. As a result, the configurations of the optical system and the reading unit can be simplified all at once, and the manufacturing cost of the entire image reading apparatus can be effectively reduced.

At this time, the optical system has an autofocus mechanism. For this reason, it becomes possible to form the light including the image information on the solid-state imaging device with high accuracy and reliability, and it is possible to obtain high-quality image information.

[Brief description of drawings]

FIG. 1 is a perspective view of an image reading apparatus according to the present invention.

FIG. 2 is a schematic perspective view of the inside of the image reading device with a part thereof cut away.

FIG. 3 is a schematic configuration diagram of the inside of the image reading apparatus.

FIG. 4 is a schematic configuration perspective view of a moving mechanism that constitutes the image reading apparatus.

FIG. 5 is an enlarged plan view of an optical system and a reading unit which form the image reading apparatus.

FIG. 6 is a front explanatory view of an ND filter which constitutes the image reading apparatus.

FIG. 7 is a partially sectional front view of the image reading apparatus.

FIG. 8 is a cross-sectional plan view of a transillumination unit that constitutes the image reading apparatus.

FIG. 9 is a diagram illustrating a reading operation of a transmissive read original by the transillumination unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Image reading device 14 ... Frame part 16, 18 ... Accommodating part 20 ... Reference seat 22 ... Original placement table 24, 24a ... Read original 26 ... Glass plate 28 ... Chart plate 30 ... Shading reference plate 32 ... Original pressing plate 40 ... Illumination unit 42 ... Moving mechanism 44 ... Optical system 46 ... Reading unit 48 ... Light source unit 50 ... Reflecting mirror unit 66 ... Conveying motor 74 ... Lens group 76 ... Auto zoom mechanism 78 ... Auto iris mechanism 80 ... Auto focus mechanism 82 ... ND filter 84 ... Swing mechanism 116a-116
c ... Color separation prisms 118a to 118c ... CCD 120 ... Support member 122 ... Motor 140 ... Cooling mechanism 170 ... Transmitted illumination section 172 ... Main body section 174 ... Conveying motor 184 ... Moving casing

Claims (4)

[Claims] 1. An illumination unit for irradiating the read document with illumination light to obtain light containing image information carried on the read document, and light for collecting the image information obtained through the illumination unit. A fixed type optical system with a zoom mechanism that emits light, and a reading unit that photoelectrically reads image information included in the light condensed by the optical system, wherein the reading unit is arranged on an optical path of the light. And a color separation prism integrally fixed to the optical system, and integrally fixed to the color separation prism for photoelectrically reading image information contained in the light of each color obtained by the color separation prism. An image reading apparatus comprising: a plurality of solid-state imaging devices. 2. The image reading apparatus according to claim 1, wherein the optical system has an autofocus mechanism. 3. The image reading apparatus according to claim 1, wherein the optical system includes an ND filter, and the ND filter is swung to arrange the ND filter on an optical path of the light and outside the optical path. An image reading apparatus comprising: a swing mechanism. 4. The image reading device according to claim 1, further comprising a frame section, wherein the frame section includes a first housing section in which the illumination section, the optical system, and the reading section are arranged, a power source, and a substrate. An image reading apparatus characterized in that a second accommodating section in which a control section including a section is arranged, and the second accommodating section are separately provided.