JP2000349972A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To read images at a high speed by allowing an image forming lens to capture more light quantities so as to efficiently utilize light light from a light source. SOLUTION: An acrylic lens 68 is placed close to a light emission face of an LED chip group 64 of the image reader, and an acrylic lens 70 is placed close to a photo film 22 at a prescribed interval with the acrylic lens 68. Furthermore, an aspherical lens with a light collection power in the subscanning direction is formed to an emission face 68B of the acrylic lens 68 and an incident face 70A of the acrylic lens 70. Thus, the light within a range of a prescribed diffusion among divergent lights emitted from the LED chip group 64 is made incident onto the incident face 68A of the acrylic lens 68, the light is collected in the subscanning direction by the emission face 68B and the incident face 70A, to have directivity and more divergent lights are led close to a face of the photo film 22 and captured by a lens unit 76.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image reading apparatus for obtaining image data by reading transmitted light or reflected light from a frame image while transporting a document on which a plurality of frame images are recorded.

[0002]

2. Description of the Related Art In recent years, a frame image recorded on an original such as a photographic film is photoelectrically read by a reading sensor such as a CCD and image processing such as enlargement / reduction and various corrections is performed on the read digital image data. There is known a technique of executing an image and forming an image on a recording material by a laser beam modulated based on the image-processed digital image data.

In the technique of digitally reading a frame image using such a reading sensor such as a CCD or the like, in order to realize accurate image reading, the frame image is preliminarily read by so-called "pre-scanning". A reading condition (for example, a light amount applied to a frame image, a charge accumulation time of a CCD, and the like) according to the density and the like of the frame image is determined, and the frame image is read again based on the determined reading condition. Thus, a two-step reading process is performed.

In the above-described image reading system, as a light source, a halogen lamp which has been frequently used for printing exposure and the like is used. However, since this halogen lamp generates a large amount of heat when emitting light, its luminous efficiency is poor and the increase in reading speed is limited.

That is, a halogen lamp is most suitable as a light source for printing through a negative film and directly printing on photographic paper as in printing exposure.
(Usually, a line CCD in which filters are attached so as to be sensitive to each of the three primary colors) An image reading system has a short wavelength (blue (B) system in terms of color) due to low color temperature. ) Is reduced, and the S
/ N is degraded, which hinders high-speed reading.

For this reason, it has been proposed to use an LED as a light source when a system for reading an image is a CCD. Since LEDs usually emit light of specific colors (blue: B, green: G, red: R), a white light source is configured by arranging these LEDs in a group. In addition, LEDs generate a small amount of heat and have a high color temperature, and thus are suitable as light sources for image reading systems using CCDs.

On the other hand, a color filter is attached to the line CCD on the reading side for each line, and each line CCD detects the density (light amount) of each color. The image reading system is also provided with an imaging lens for imaging light emitted from a light source and transmitted through a negative film on a line CCD.

[0008]

However, the size of the aperture of the above-mentioned imaging lens is limited in order to secure the resolution when reading the image of the line CCD. Therefore, the light transmitted through the negative film and guided to the imaging lens is restricted to a range corresponding to the size of the opening. That is, only light having a limited angle can be taken into the imaging lens. The reduction in the amount of light by the imaging lens leads to a decrease in efficiency in using the light from the light source.

Further, in this case, the transport speed of the negative film must be reduced in order to secure the amount of light required for image reading by the line CCD, and the image reading time is lengthened. This causes a problem that productivity is reduced.

In view of the above facts, the present invention provides an image reading apparatus capable of efficiently utilizing light emitted from a light source by introducing a larger amount of light into an imaging lens and thereby reading an image at a high speed. The task is to

[0011]

According to a first aspect of the present invention, there is provided an image reading apparatus for reading an image while conveying the original on which the image is recorded, wherein the image is perpendicular to a conveying direction of the original. A light emitting element group provided along the direction,
A light guide member having an incident surface arranged close to the light emitting element group and guiding light in a range of a predetermined diffusion degree of divergent light emitted from the light emitting element group to near the document surface; and the light guide member And a photoelectric conversion element that receives transmitted light or reflected light from the document irradiated by light emitted from the emission surface of the document and performs photoelectric conversion, and forms an image of the transmitted light or reflected light from the document on the photoelectric conversion element. And an image forming lens.

That is, according to the present invention, of the divergent light emitted from the light emitting element group, the light having a predetermined diffusion degree within the range of the document surface is transmitted by the light guide member whose incident surface is disposed close to the light emitting element group. You will be guided close. Further, the document is illuminated with light emitted from the emission surface of the light guide member, and transmitted light or reflected light from the document is imaged on the photoelectric conversion element by the imaging lens. In this photoelectric conversion element, the image of the document is read by photoelectrically converting the received light from the imaging lens.

As described above, since the divergent light emitted from the light emitting element group can be guided more to the vicinity of the document surface, the divergent light emitted from the light emitting element group can be used efficiently. This also increases the amount of light received by the photoelectric conversion element, so that an image can be read at high speed.

According to a second aspect of the present invention, in the image reading apparatus according to the first aspect, at least one of an incident surface and an emission surface of the light guide member is emitted from the light emitting element group. A divergent light in the sub-scanning direction of the original document.

According to the second aspect of the present invention, the incident surface or the outgoing surface of the light guide member is an aspherical lens having a light refracting surface shape having a power for condensing light in the sub-scanning direction of the document. While condensing in the scanning direction, the light is guided to the imaging lens with directivity. Therefore, more light reaches the photoelectric conversion element via the imaging lens, and the amount of light received by the photoelectric conversion element increases.

According to a third aspect of the present invention, in the image reading apparatus according to the second aspect, the lens surface shape of the aspherical lens has a larger curvature as the distance from the optical axis of the lens surface increases. .

That is, according to the third aspect of the present invention, the lens surface at the entrance surface or the exit surface of the light guide member is an aspheric lens whose curvature increases as the distance from the optical axis increases. Therefore, more light radiating from the light source located on the optical axis can be condensed more, and condensing efficiency can be improved.

According to a fourth aspect of the present invention, in the image reading apparatus according to any one of the first to third aspects, the light guide member is provided in a light guide path from the light emitting element group to the document. A plurality of light guide members are provided, and the power of condensing the divergent light is dispersed to the aspherical lens on the entrance surface or the exit surface of each of the plurality of light guide members.

That is, according to the fourth aspect of the present invention, since the light guide member is divided into a plurality of light guide members, each light guide member is compared with a case where a light guide path from the light emitting element group to the document is formed by a single continuous light guide member. The member can be reduced in size.

Further, since the condensing power for condensing the divergent light in the sub-scanning direction of the document is dispersed in the shape of the lens on the entrance surface or the exit surface of each light guide member, the entrance surface of a single light guide member is provided. Alternatively, the curvature of the aspherical lens of each lens shape can be reduced as compared with the case where the light exiting surface is provided with the condensing power.

Accordingly, the lens shape of each light guide member can be easily processed, and the size of the light guide member can be reduced, so that the manufacturing cost can be reduced.

Further, it is possible to improve the light collection efficiency by dispersing the light collection power, and it is also possible to take more light into the imaging lens.

According to a fifth aspect of the present invention, in the image reading apparatus according to any one of the first to fourth aspects, the light emitting element group is embedded in the light incident surface of the light guide member. It is characterized by:

That is, according to the fifth aspect of the present invention, since the light emitting element group is embedded in the incident surface of the light guide member, more divergent light emitted from the light emitting element group is guided into the light guide member. The divergent light can be used more efficiently.

[0025]

1 and 2 show a schematic configuration of a digital laboratory system 10 according to an embodiment of the present invention.

As shown in FIG. 1, the digital lab system 10 includes a line CCD scanner 14, an image processing unit 1
6, a laser printer unit 18, and a processor unit 20. Here, the line CCD scanner 1
4 and the image processing unit 16 are integrated as an input unit 26 shown in FIG. 2, and the laser printer unit 18 and the processor unit 20 are integrated as an output unit 28 shown in FIG.

The line CCD scanner 14 is for reading a frame image recorded on a photographic film such as a negative film or a reversal film. For example, a 135 size photographic film, a 110 size photographic film, and a transparent film are used. It is possible to read a frame image of a photographic film on which a magnetic layer is formed (240-size photographic film: so-called “APS film”), and 120- and 220-size (Brownie size) photographic films. The line CCD scanner 14 reads the above-mentioned frame image to be read by the three-line CCD 30 and performs A / D
After the A / D conversion in the converter 32, the image data is output to the image processing unit 16.

The image processing section 16 stores image data (scanned image data) output from the line CCD scanner 14.
Is input, image data obtained by photographing with the digital camera 34 or the like, and a document (for example, a reflection document)
Data obtained by reading the image data with a scanner 36 (floodbed type), image data generated by another computer and stored in a floppy disk drive 38, an MO drive or a CD drive 40, and received via a modem 42 It is also configured to be able to input communication image data and the like from the outside.

The image processing section 16 stores the input image data in the image memory 44, and stores a color gradation processing section 46, a hypertone processing section 48, and a hyper sharpness processing section 50.
Image processing such as various corrections and the like, and outputs the image data to the laser printer unit 18 as recording image data. Further, the image processing unit 16 outputs the image data subjected to the image processing to an external device as an image file (for example, outputs the image data to a recording medium such as an FD, an MO, a CD, or to another information processing device via a communication line). Transmission, etc.).

The laser printer section 18 has R, G, and B laser light sources 52, and controls a laser driver 54 to record image data (temporarily stored in an image memory 56) input from the image processing section 16. Is applied to the photographic printing paper, and scanning exposure (in the present embodiment, mainly the polygon mirror 58 and the fθ lens 60) is performed.
An image is recorded on the photographic paper 62 by an optical system using the same. Further, the processor unit 20 includes a laser printer unit 18.
The photographic paper 62 on which an image has been recorded by scanning exposure is subjected to color development, bleach-fix, washing, and drying. Thus, an image is formed on the printing paper 62.

(Configuration of Line CCD Scanner) Next, the configuration of the line CCD scanner 14 will be described.

In this embodiment, a digital lab system 10 in which a 135-size photographic film 22 is used will be described.

FIG. 3 shows a schematic configuration of an optical system of the line CCD scanner 14. This optical system uses an LED chip group 64 in which a plurality of LED chips are assembled, and includes a light source 66 for irradiating the photographic film 22 with light.

The LED chip groups 64 are arranged in one row (or in two or more rows) along the width direction of the photographic film 22 being conveyed. On the light emitting surface side of the LED chip group 64, an acrylic lens 68 is provided.
4 and the acrylic lens 68
And acrylic lens 70 installed at a predetermined interval
Are arranged close to the photographic film 22 side.

The acrylic lens 68 is connected to the LED chip group 6
4 is a flat surface (incidence surface 68A), and an aspheric lens (emission surface 68B) having condensing power in the sub-scanning direction is formed on the side facing the acrylic lens 70.

As a result, of the divergent light emitted from the LED chip group 64 in a substantially radial shape, the light having a predetermined degree of diffusion incident on the incident surface 68A of the acrylic lens 68 is converted into the emission surface 68B of the acrylic lens 68. The light is refracted in the sub-scanning direction by the (aspherical lens) and collected. The curvature of the exit surface 68B of the acrylic lens 68 increases as the distance from the optical axis increases, and the incident light from the LED chip group 64 is set to be substantially parallel in the sub-scanning direction.

The acrylic lens 70 has an aspherical lens (incident surface 70A) having a condensing power in the sub-scanning direction on the side facing the acrylic lens 68, and has a main surface on the side facing the photographic film 22. An aspherical lens (outgoing surface 70B) having a condensing power in the scanning direction is formed, and further, a substantially fan-shaped shape in which the width (in the direction of the arrow W in the drawing) increases from the incoming surface 70A to the outgoing surface 70B. It has been.

Thus, the light emitted from the exit surface 68B of the acrylic lens 68 and incident on the acrylic lens 70 is refracted again in the sub-scanning direction by the incident surface 70A (aspherical lens), and from the exit surface 70B to the photographic film. The light is emitted to the side 22. The curvature of the incident surface 70A of the acrylic lens 70 is set so that the width of the light irradiated on the photographic film 22 in the sub-scanning direction is condensed to a predetermined width. The curvature of the exit surface 70B in the main scanning direction is set so as to converge the light irradiated on the photographic film 22 in the main scanning direction and irradiate a predetermined range of the width dimension of the photographic film 22.

As described above, of the divergent light emitted from the LED chip group 64, light having a predetermined degree of diffusion is guided to the vicinity of the photographic film 22 by the acrylic lenses 68 and 70, and is transmitted in the sub-scanning direction and in the main scanning direction. While condensing in the scanning direction, the light is guided with directivity, and the acrylic lens 7
The photographic film 22 is radiated from the zero emission surface 70B.

On the other hand, on the opposite side of the light source 66 across the photographic film 22 positioned and conveyed by the negative carrier 74, a spherical surface for forming light transmitted through the frame image along the optical axis of the LED chip group 64 (FIG. (Or an aspherical surface) lens unit 76 and a three-line CCD 30 are sequentially arranged.

The lens unit 76 is a zoom lens composed of a plurality of lenses, and has a role of forming an image of light from the LED chip group 64 at a predetermined position. , A three-line CCD 30 is arranged.

In the three-line CCD 30, a plurality of pixels for detecting light are arranged along the width direction of the photographic film 22, and three lines are provided in the film transport direction. Each line of pixels has three primary colors (R, G, B)
(Not shown) for each color are provided for each color.
Light reception for each of G and B colors is enabled.

As a result, the light passes through the photographic film 22,
The light imaged on the three-line CCD 30 by the lens unit 76 is accumulated (one-dimensionally) by the three-line CCD 30 as a charge according to the light sequentially received from one end pixel to the other end pixel of each column, Combined with the photographic film 22 being transported, the frame image (two-dimensional) is
It is electrically read for each of the colors G and B.

The operation of the present embodiment will be described below.

The operator inserts the photographic film 22 into the negative carrier 74 (film carrier), and
When the start of frame image reading is instructed by the keyboard 16K of No. 6, the transport of the photographic film 22 is started in the negative carrier 74. By this transport, a pre-scan is performed. That is, while conveying the photographic film 22 at a relatively high speed, the line CCD scanner 14 reads not only image frames but also various data outside the image recording area of the photographic film 22. The read image is displayed on the monitor 16M.

At this time, the size of the frame image is recognized. For example, in the case of a panorama size frame image, the pixel missing portions (both ends in the width direction of the photographic film) unique to the panorama size are shielded from light.

Next, the reading conditions at the time of fine scanning are set for each frame image based on the prescan result of each frame image, and the reading conditions at the time of fine scanning are set based on the prescan result. It is set every time.

When the setting of the reading conditions at the time of the fine scan for all the frame images is completed, the photographic film 22 is set.
Is conveyed in the direction opposite to the prescan, and a fine scan of each frame image is executed.

At this time, since the photographic film 22 is being conveyed in the direction opposite to that in the pre-scan, the fine scan is executed sequentially from the last frame to the first frame.
The transport speed of the fine scan is set lower than that of the pre-scan, and the reading resolution is accordingly increased.
Also, at the time of pre-scanning, since the image state (for example, the photographed image aspect ratio, the photographing state such as under, normal, over, super over, and the presence or absence of strobe photographing) is recognized, it is necessary to read the image under appropriate reading conditions. Can be.

Here, the line CC in the present embodiment
The light source 66 applied to the D scanner 14 is not a halogen lamp or a xenon lamp, which has been widely used in the past, but is an L light source.
The ED chip group 64 is applied. LED chip group 64
Are arranged almost linearly at high density along the width direction of the photographic film 22, and this straight line is
It faces the 0 reading line.

The divergent light emitted from the LED chip group 64 is converted into an acrylic lens 68 disposed close to the LED chip group 64 and an emission surface 68B of the acrylic lens 68.
With the acrylic lens 70 disposed opposite to the side, the light having a predetermined diffusion degree in the divergent light is condensed in the sub-scanning direction, and the light has a directivity. The film is guided to near the film 22 surface.

Further, the exit surface 70 of the acrylic lens 70
A is irradiated on the photographic film 22 by the light emitted from the lens unit A, and the transmitted light from the photographic film 22 is
6 forms an image on the three-line CCD 30. In this three-line CCD 30, the lens unit 76
Photographic film 22 by photoelectrically converting light from
Is read.

As described above, by arranging the incident surface 68A of the acrylic lens 68 close to the LED chip group 64, of the divergent light emitted from the LED chip group 64, the light within the predetermined diffusion degree range Is incident on the incident surface 68A of the acrylic lens 68, more divergent light is guided to the vicinity of the photographic film 22, and the divergent light emitted from the LED chip group 64 is efficiently used.

Further, since the amount of light received by the three-line CCD 30 is also increased, an image can be read at a high speed.

Further, the exit surface 68 of the acrylic lens 68
B, and the incident surface 70A of the acrylic lens 70
The divergent light emitted from the chip group 64 is transferred to the photographic film 22.
The divergent light emitted from the LED chip group 64 is condensed by refraction in the sub-scanning direction, and the light has a directivity. The photographic film 22 is irradiated.

Further, since the lens surface shape at the light exit surface 68B is an aspheric lens whose curvature increases as the distance from the optical axis increases, the refractive index outside the lens surface is high, and the light is emitted radially from the LED chip group 64. More divergent light can be collected, and the light collection efficiency is improved. Therefore,
More light can be taken into the lens unit 76.

In this embodiment, two acrylic lenses (acrylic lenses 68 and 70) are arranged between the light guide paths from the LED chip group 64 to the photographic film 22. Thereby, the material for forming the acrylic lens can be reduced as compared with the case where a single acrylic lens is arranged between the light guide paths from the LED chip group 64 to the photographic film 22 to form the light guide path. The acrylic lenses 68 and 70 are miniaturized.

Further, the exit surface 68 of the acrylic lens 68
In this embodiment, the incident surface 70A of the B and acrylic lens 70 is an aspheric lens having a condensing power in the sub-scanning direction of the photographic film 22, and the divergent light emitted from the LED chip group 64 is collected in the sub-scanning direction. Condensing power for light emission is distributed to the lens surfaces of the exit surface 68B and the entrance surface 70A. Thereby, the curvature of the aspherical surface of the lens surface at the exit surface 68B and the entrance surface 70A is smaller than when a single acrylic lens has the same light-collecting power. Furthermore, the emission surface 70B of the acrylic lens 70
Is an aspherical lens having a light condensing power in the main scanning direction, so that a light condensing function in the main scanning direction is also provided in the light guide path for converging divergent light in the sub-scanning direction.

As described above, the light condensing power in the sub-scanning and main scanning directions is dispersed over a plurality of surfaces (lens surfaces), and the light condensing functions in the sub-scanning and main scanning directions are provided independently on each surface. Thereby, the lens shapes of the entrance surface and the exit surface of each acrylic lens can be easily processed. At the same time, the manufacturing cost of the acrylic lens can be reduced in addition to the miniaturization of each acrylic lens as described above.

In the present embodiment, the exit surface 68B of the acrylic lens 68 and the entrance surface 7 of the acrylic lens 70 are used.
Although 0A is formed in a lens shape having a condensing power in the sub-scanning direction, the arrangement of these lens shapes is not limited to this embodiment. For example, various combinations are possible, such as applying a lens shape for condensing light in the sub-scanning direction also to the emission surface 70B of the acrylic lens 70,
In this case, the light-collecting efficiency can be further improved by dispersing the light-collecting power.

In this embodiment, the LED chip group 6
A configuration was adopted in which two acrylic lenses were disposed between the light guide paths from No. 4 to the photographic film 22. However, the number of acrylic lenses is not limited to this, and three or more acrylic lenses can be provided. As a result, in addition to the above-described effects of reducing the size of the acrylic lens and improving the light collection efficiency, the distance between the light guide path and the line CCD
The degree of freedom in designing, for example, changing the position and the number of the acrylic lenses according to the structure of the scanner unit and the like is also increased.

Further, in this embodiment, the arrangement of the LED chip group 64 and the acrylic lens 68 is separated from each other by a predetermined distance. However, the arrangement of the LED chip group is not limited to this embodiment. For example, as shown in FIG. 6, a structure in which the LED chip group 64 is directly molded on the incident surface 68A of the acrylic lens 68 can be applied. In this case, since the divergent light emitted from the LED chip group 64 is easily guided into the acrylic lens 68, the divergent light can be used more efficiently.

In the present embodiment, the photographic film 22
However, the present invention is applicable to reading of a reflection original.

As a lens unit for image formation,
Although the spherical (or aspheric) lens unit 76 is applied, a self-fox lens may be applied.

[0065]

Since the image reading apparatus of the present invention has the above-described configuration, a larger amount of light is taken into the imaging lens, so that the light emitted from the light source can be used efficiently, and the image can be read at high speed. it can.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a digital laboratory system according to an embodiment of the present invention.

FIG. 2 is an external view of a digital laboratory system.

FIG. 3 is a perspective view showing a schematic configuration of an optical system of the line CCD scanner.

FIG. 4 is a plan view showing a schematic configuration of an optical system of the line CCD scanner.

FIG. 5 is a side view showing a schematic configuration of an optical system of the line CCD scanner.

FIG. 6 is a side view showing a schematic configuration of an optical system of a line CCD scanner in a modification in which a line CCD is provided in an acrylic lens.

[Explanation of symbols]

 Reference Signs List 10 digital lab system 14 line CCD scanner (image reading device) 22 photographic film (document) 30 3-line CCD (photoelectric conversion element) 64 LED chip group (light emitting element group) 66 light source 68 acrylic lens (light guide member) 68A entrance surface 68B Outgoing surface (aspherical lens) 70 Acrylic lens (light guide member) 70A Incident surface (aspherical lens) 70B Outgoing surface 76 Lens unit (imaging lens)

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) H04N 1/113 H04N 1/04 104Z F-term (Reference) 2H087 KA00 LA24 PA01 PA02 PA17 PB01 PB02 QA01 QA05 QA07 QA13 QA21 QA33 QA41 RA07 RA42 RA45 UA01 5B047 AA01 AB04 BA01 BB03 BC05 BC07 CA19 CB04 5C051 AA01 BA03 DA03 DB01 DB22 DB23 DB29 DC04 DE15 DE30 FA04 5C072 AA01 BA01 BA03 BA05 BA19 BA20 CA05 CA14 DA02 DA09 DA21 EA05 NA02 UA06 UA11 UA11

Claims (5)

[Claims] While conveying a document on which an image is recorded,
An image reading apparatus for reading the image, wherein a light emitting element group provided along a direction orthogonal to a document conveyance direction, and an incident surface is arranged close to the light emitting element group, and the light emitting element group A light guide member that guides light in a range of a predetermined degree of diffusion of the emitted divergent light to near the document surface; and transmitted light or reflection from the document irradiated by light emitted from the emission surface of the light guide member. An image reading apparatus, comprising: a photoelectric conversion element that receives light and performs photoelectric conversion; and an imaging lens that forms transmitted light or reflected light from the document on the photoelectric conversion element. 2. The light guide member, wherein at least one of an incident surface and an outgoing surface has a power to converge divergent light emitted from the light emitting element group in a sub-scanning direction of the document. 2. The image reading device according to claim 1, wherein the image reading device is an aspheric lens having a refractive surface shape. 3. The image reading apparatus according to claim 2, wherein the curvature of the lens surface of the aspherical lens increases as the distance from the optical axis of the lens surface increases. 4. The light guide member is provided by being divided into a plurality of portions between a light guide path from the light emitting element group to the document, and reduces a condensing power for the divergent light with each of the plurality of light guide members. The image reading device according to claim 1, wherein the image reading device is dispersed in an aspheric lens on an entrance surface or an exit surface. 5. The image reading device according to claim 1, wherein the light emitting element group is embedded in the light incident surface of the light guide member.