JP3181974B2 - Transparency document reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent original reading apparatus applied to an original reading section of a film scanner, a copying machine or the like.

[0002]

2. Description of the Related Art There has been proposed an image reading apparatus which irradiates a light beam from a light source from one side of a transmission original with diffusion light, forms an image of the transmitted light on a photoelectric conversion element by an imaging optical system, and reads the transmission original. (JP-A-3-91367, JP-A-3-34
No. 764). Here, the "image reading apparatus" described in JP-A-3-91367 is provided with an illumination unit for reading a transparent original, in addition to a normal reflective original reading unit. However, the present invention does not relate to the illuminance distribution on the diffuser, but according to the illustrated transmissive original illumination unit, the diffuser is directly illuminated by the divergent light from the light source, thereby improving the illuminance on the original surface. No measures have been taken. Also, JP-A-3-3476.
The same applies to the “image reading device” described in Japanese Patent Publication No.

[0003]

When reading a transparent original, the original is often an image that requires high-definition quality, so that a high-quality reading device is required. That is, there is a need for a transmissive original reading device having high resolution and high gradation. For this reason, drum scanners are commonly used in the field of printing. However, the drum scanner itself is large and expensive, so that it has been used only by some specialized companies. Therefore, a relatively inexpensive flat bed type scanner as shown in FIG. 9 has been developed as a transparent original reading apparatus. In FIG. 9, reference numeral 1 denotes a transmissive original illumination unit, 2 denotes a light source, 4 denotes a diffusion plate, 6 denotes a transmissive original, 9 denotes a contact glass, 10 denotes a first mirror, 11 denotes a second mirror, and 12 denotes an imaging lens. , 13 are photoelectric conversion elements.

In this flatbed type scanner, a light source 2 for illuminating a transparent original is provided on the opposite side of the reading optical system with respect to the original 6, as shown in FIG. in this case,
As a reading method, there are a type in which the light source and the reading optical system are scanned in synchronization with the fixed document, and a type in which the document is scanned with the light source and the reading optical system fixed. In any case, as the illumination light source 2 of the flatbed scanner, a fluorescent lamp is often used because of its easy handling. However, the fluorescent lamp has difficulty in obtaining high illuminance and has poor illuminance stability. However, there are many problems for high-precision reading. Halogen lamps, on the other hand, are difficult to handle, such as generating heat, but are easy to obtain high illuminance and stable in terms of light quantity.
It can be said that it is suitable for ensuring high performance.

However, when a fluorescent lamp is used as a light source in the apparatus shown in FIG. 9, a uniform illuminance distribution can be obtained on a transmissive original even if the arrangement of the light source is slightly changed. On the other hand, when a halogen lamp is used as the light source 2, as shown in FIG.
It is necessary to collect light. Therefore, the reflector 3
And the light source 2 is arranged at one focal point of the ellipse.
It is common to place a light-collecting surface at the other focal point. However, in this case, even if the arrangement relationship between the halogen lamp and the reflector is slightly deviated, as shown in FIGS. 11A, 11B, and 11C, the light distribution on the condensing surface of the diffusion plate 4 is changed. It fluctuates greatly and light cannot be collected sufficiently. For this reason, the shape of the reflector 3 is devised, or the light condensing rate is intentionally reduced to suppress the fluctuation of the light distribution due to an arrangement error. As described above, despite the use of the halogen lamp, the illuminance of the document surface cannot be sufficiently increased, and the cost of the illumination device may be increased. SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a transparent document reading apparatus provided with a transparent document illuminating unit that is resistant to a placement error of a light source without using a reflector having a complicated shape. The purpose is to:

[0006]

In order to achieve the above object, the invention of claim 1 is to provide a linear light source that is long in the main scanning direction,
It is arranged behind the light source and reflects and condenses the light flux from the light source.
And a light beam from the light source and the reflector.
Having a diffused light generating means (for example, a diffuser) for diffusing light
A transparent original illumination unit, and the transparent original illumination
It is placed at the diffused light illumination position from the
Document holding means, and the document holding means
The document is placed on the opposite side of the transparent document illumination unit and transmits the document.
Image forming optical system for forming a focused light beam and image forming of the image forming optical system
A photoelectric conversion element disposed at
The bright unit, the light beam from the light source to diffuse the illumination from one side of the transparent original, the transmitted light is imaged on the photoelectric conversion element by the imaging optical system, in transparent original reading apparatus for reading a transparent original, the transmitting original Lighting unit diffused light emission
Diffuse light from light source and reflector
It is characterized in that a pair of opposing reflectors that reflect and converge toward the raw means are provided.

[0007] The second aspect of the present invention, when the transparent original reading apparatus according to claim 1, Ru provided a gap between the <br/> diffused light generating means and the opposing reflecting plate of the transparent original illumination unit co
Means for cooling the inside of the transparent original illumination unit .

[0008] The invention according to claim 3, in the transmission document reading apparatus according to claim 1, wherein, of said transparent original illumination unit
The opposing reflector is elongated in the main scanning direction corresponding to the linear light source.
In addition, the shape of the opposing reflection plate or the area of the effective reflection portion is changed in the main scanning direction , and the opposing reflection with respect to the main scanning direction is changed.
It is characterized in that shading correction in the main scanning direction is performed by changing the reflection area of the firing plate .

According to a fourth aspect of the present invention, there is provided the transparent original reading apparatus according to the first aspect, wherein the image forming optical system includes a single image forming optical system.
Image element and a plurality of images from the image forming element in the main scanning direction.
An image in the main scanning direction transmitted through the original is formed on a plurality of photoelectric conversion elements by the image forming element and the image dividing means, and these are connected to each other in the main scanning direction. transmitted through the document reader, on which the image is
The opposing reflector of the transparent original illumination unit supports linear light sources
And is long in the main scanning direction, and
Is a part corresponding to the image dividing unit by the image dividing means.
Is characterized in that the area of the effective reflecting portion is wider than the other portions.

According to a fifth aspect of the present invention, there is provided the transmission source according to the first aspect.
In the original reading apparatus, the transparent original illumination unit
The reflector installed on the back of the light source emits light from the light source.
An ellipse or paraboloid that converts scattered light into parallel or convergent light
Or if they have a curved surface shape similar to them,
Curved surface corresponding to the shape of the above reflector
It is characterized by having a shape .

[0011] The invention of claim 6 is the transparent original reading apparatus according to claim 5, characterized in that set in the original side of the focal point of the diffused light generating means on or diffused light generating means of the opposing reflecting plate .

[0012]

According to the first aspect of the present invention, there is provided a transparent original reading apparatus.
A light source and a light source are provided on the diffused light generating means of the transmission original illumination unit.
The light flux from the reflector is reflected toward the diffused light generation means.
Since the pair of opposing reflectors for condensing light is provided, the light beam from the light source can be condensed by the opposing reflector, and the light beam from the light source can be efficiently used for document illumination.

[0013] In the transparent original reading apparatus according to claim 2, cold Rutotomoni, a transparent original illumination unit provided a gap between the counter reflector as described in claim 1 and diffused light generating means
Means for preventing the heat from accumulating in the area surrounded by the opposing reflector even when a light source with high heat generation such as a halogen lamp is used. Can be avoided from danger such as deformation and breakage of

According to a third aspect of the present invention, the shape of the opposed reflecting plate or the substantial area of the reflecting portion is changed in the main scanning direction.
Since the shading correction in the main scanning direction is performed by changing the reflection area of the directional reflection plate , the original can be uniformly illuminated in the main scanning direction in addition to the effect of the first aspect.

According to a fourth aspect of the present invention, there is provided a transparent original reading apparatus which forms an image.
The optical system consists of a single imaging element and the image from that imaging element.
Image dividing means for dividing the
In a transmission original reading apparatus, an image in the main scanning direction transmitted through a document is formed on a plurality of photoelectric conversion elements by the image forming element and the image dividing means, and these are connected to form an image in the main scanning direction. Opposing reflection of the above-mentioned transparent original illumination unit
The plate is elongated in the main scanning direction corresponding to the linear light source, and
And the opposing reflector is used for image division by the image dividing means.
Since the area of the effective reflecting portion of the portion corresponding to the split portion is made wider than the other portions, the illuminance near the split portion can be increased as compared with other regions, and the amount of light near the split portion can be reduced. The problem of deterioration can be solved.

According to a fifth aspect of the present invention, the shape of the opposing reflecting plate is approximated to an ellipse or a paraboloid corresponding to the shape of the reflector placed on the back of the light source.
Due to the curved shape, the light beam emitted from the light source placed at the focal point of the reflector can be focused again at the focal position of the opposing reflector. In other words, when the opposing reflector was flat, there was a light flux that returned to the light source direction without reaching the diffuser during multiple reflection between the opposing reflectors. Thus, the light flux from the light source can be efficiently collected, and the return light to the light source can be eliminated, so that the document can be more efficiently illuminated.

According to a sixth aspect of the present invention, there is provided a transmissive original reading apparatus, wherein the curved reflecting surface of the opposed reflecting plate has a focal position on the diffuser surface or closer to the original than the reflecting plate. Is designed, all the light beams reflected by the opposing reflection plate illuminate the diffusion plate, so that more efficient illumination is possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a schematic structural view of an essential part of a transparent original reading apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a transmissive original illumination unit, 2 denotes a light source, 3 denotes a reflector, 4 denotes a diffuser as diffused light generating means, 5 denotes an original holder, 6 denotes a transparent original, and 7 denotes a pair mounted on the diffuser. Is a counter reflector. Although not shown, an image forming optical system as shown in FIG. 9 is disposed on the opposite side of the original holder 5 from the illumination unit 1. In FIG. 1, a linear light source such as a halogen lamp is considered as the light source 2. The light beam emitted from the light source 2 is condensed on the diffusion plate 4 by the reflector 3 and the opposing reflection plate 7 arranged on the front surface of the diffusion plate 4. The light beam diffused by the diffusion plate 4 illuminates the transmissive document 6 held by the document holder 5, and the light transmitted through the transmissive document 6 is imaged on a photoelectric conversion element by an imaging optical system (not shown). Is read.

In the transmissive original reading apparatus having the configuration shown in FIG. 1, as shown in FIG. 2A and FIG. On the other hand, even if there is an error in the installation of the halogen lamp, the divergent light beam which is not condensed can be turned inward by the opposing reflection plate 7, and the illuminance unevenness as shown in FIG. Can be almost uniformly illuminated in the sub-scanning direction, and the original illumination illuminance can be increased. Further, even when there is no installation error of the halogen lamp as shown in FIG. 2B, the direct light diverging without passing through the reflector can be used for illumination in a region surrounded by the opposing reflector 7 by the opposing reflector 7. Therefore, the original illumination illuminance can be increased.

Next, FIG. 3 is a schematic view of a main part of a transparent original reading apparatus according to a second embodiment of the present invention. In FIG. 3, the same reference numerals as in FIG. 1 denote the same components, but in this example, a gap is provided between the diffusion plate 4 and the opposing reflection plate 7 in the transmissive original illumination unit 1 and the light source A mirror (cold mirror) 8 is installed between 2 and the diffusion plate 4,
Further, a ventilation opening is provided in the transmissive original illumination unit 1 and a cooling fan 14 is provided so that the inside of the transmissive original illumination unit 1 can be cooled by the cooling fan 14. The flow of air in the transparent original illumination unit 1 is indicated by arrows.

When a halogen lamp is used as the light source 2 and high illuminance illumination is performed by the halogen lamp, a change in the shape of the reflector 3 due to an increase in the temperature in the transmission original illumination unit and damage to the diffusion plate 4 due to heat generated in the diffusion plate 4 And so on. Therefore, in the case of the apparatus shown in FIG. 3, a cold mirror 8 is interposed between the light source 2 and the diffusion plate 4 to bend the optical path and lengthen the optical path to reduce the heat generated in the diffusion plate 4. At the same time, the inside of the unit is air-cooled by the cooling fan 14. That is, even if the cold mirror 8 is used, considerable heat is generated on the diffusion plate, so that the diffusion plate 4 must be cooled by convection of air. However, as shown in FIG. 1, when the opposing reflecting plate 7 and the diffusing plate 4 are in contact with each other, heat is generated in a region surrounded by the opposing reflecting plate 7 and sufficient cooling is performed. Absent. In such a case, as shown in FIG. 3, the convection of air flowing on the surface of the diffusion plate can be ensured by disposing the opposing reflection plate 7 and the diffusion plate 4 apart from each other. It is possible to eliminate the accumulation of heat in the region sandwiched by the gaps and prevent the diffusion plate from being damaged by heat.

FIG. 4 shows a third embodiment of the present invention, and is an explanatory view of a shading correction method using an opposing reflecting plate of a transparent original reading apparatus. In the transmission original reading apparatus shown in FIGS. 1 and 3, it has been described that the light distribution in the sub-scanning direction can be made uniform by disposing the opposing reflection plate 7 on the front surface of the diffusion plate 4. By changing the shape of the opposing reflecting plate 7 or the effective area of the reflecting portion in the main scanning direction, the light distribution in the main scanning direction is also made uniform.

In general, in a halogen lamp light source, the length and arrangement of the filament are designed so as to correct a decrease in illuminance near both ends in the main scanning direction due to the cosine fourth law in the imaging optical system. However, in many cases, the light source 2 is designed so that the spectral distribution in the main scanning direction at a certain distance from the light source in a state without any reflector 3 or the like corrects a decrease in illuminance near both ends, and is actually used. Is very different. In particular, when reading the transmissive original 6, the original must be illuminated via the diffusion plate 4, and when the above-described opposing reflector 7 is provided, the original setting differs from the initial setting. Would. As a result, the light distribution in the main scanning direction on the document surface becomes uniform, and the shading correction as intended when designing the light source is not performed. Therefore, in order to correct a decrease in illuminance near both ends in the main scanning direction due to the cosine fourth power rule, the width of the opposing reflector 7 near the both ends may be widened and narrow near the center. Thus, the region on the diffusion plate sandwiched between the opposing reflection plates 7 can be made uniform in both the main and sub directions.

Here, the width of the opposing reflector 7 can be changed by deforming the upper end of the opposing reflector 7 as shown in FIG. 4A or by changing the lower end of the opposing reflector 7 as shown in FIG. The part may be deformed. Also, instead of changing the shape of the opposing reflection plate 7,
As shown in FIGS. 4C and 4D, the same effect can be obtained by disposing a tape-shaped member (such as a shading correction tape) that does not reflect a light beam on the reflection surface of the opposing reflection plate 7. . In this case, as in the case of FIGS. 4A and 4B, the effect is the same whether the tape is applied to either the upper or lower end of the opposing reflection plate 7.

In a general image reading apparatus,
It was enough to consider only the shading correction based on the cosine fourth law. However, in the following cases, a special shading shape must be considered. There is a transparent original reading apparatus that divides an image in a main scanning direction by a prism or the like and reads the image by a plurality of sensors. FIG. 5 shows an example of this surface-divided transmission original reading apparatus. The shading shape in the case of this device is as shown in FIG. 6, and as is clear from FIG. 6, it can be seen that the decrease in the amount of light near the division is large. Therefore, in order to correct the decrease in the amount of light near the division, as in the embodiment shown in FIG.
What is necessary is just to enlarge the substantial area of the reflection part around the divisional part of the opposing reflection plate 7. In addition, the shape for shading correction uses a ray tracing technique to adjust the length of the reflecting portion of the opposing reflecting plate so that the number of light beams reaching the diffusing plate is constant at any cross section in the main scanning direction. By determining, the shape can be determined.

Next, FIG. 8 is a schematic view of a main part of a transparent original reading apparatus according to an embodiment of the present invention. In FIG. 8, the same reference numerals as in FIG. 1 denote the same components, but in this example, when the reflector 3 installed on the back of the light source 2 is an ellipse or a mirror approximated to an ellipse,
The counter reflector 7 is characterized in that it has an ellipse having a common focus with the reflector 3 or a shape approximating the ellipse. At this time, the focal point on the opposing reflection plate side is set in a direction away from the light source 2 with respect to the diffusion plate surface or the diffusion plate 4.

In the case where the opposing reflection plate 7 is constituted by a plane mirror as in the transmission original reading apparatus shown in FIG.
However, there is a light flux returning to the light source direction without reaching the light source, and the illumination efficiency cannot be said to be sufficiently high. However, according to the transmission original reading apparatus shown in FIG. 8, due to the nature of the ellipse, of the light flux emitted from the light source located at one focal point of the ellipse, Since the light is condensed at another focal point, no return light is generated, and the diffuser can be efficiently illuminated. The same effect can be applied to the case where the shape of the reflector is a paraboloid or a paraboloid. In the case of a paraboloid, it is possible to convert the light beam emitted from the light source placed at the focal point into parallel light,
Parallel light can be converged at the focal point. Therefore, by making the shape of the opposing reflecting plate a parabolic surface or a shape similar to the parabolic surface, the spread light beam can be condensed in a narrow area, and efficient illumination becomes possible.

In FIG. 8, the focal position of the opposing reflection plate 7 having an ellipse, a paraboloid or a shape similar thereto is set on the diffusion plate 4 or higher than the diffusion plate 4 as in the invention of claim 6. By designing the shape so as to be on the document 6 side, the document can be illuminated more effectively.

[0029]

As described above, in the transparent original reading apparatus according to the first aspect, the size of the transparent original illumination unit is increased.
The luminous flux from the light source and the reflector is spread on the diffused light generation means.
Since a pair of opposing reflectors that reflect and converge toward the diffused light generator are installed, the light flux from the light source can be condensed on the condensing surface of the diffused light generator by the opposing reflector, and Can be efficiently used for document illumination, and high-definition image reading with a high S / N ratio can be performed.

[0030] In the transparent original reading apparatus according to claim 2, in addition to the effects of claim 1, when Ru is provided a gap between the diffused light generating means and a counter reflector as described in claim 1 co
Means for cooling the inside of the transmissive original illumination unit, so that even when a light source with high heat generation such as a halogen lamp is used, heat accumulation occurs in the area surrounded by the opposing reflection plate. Deformation of components due to heat
It can be avoided from danger such as breakage.

According to the third aspect of the present invention, the shape of the opposed reflecting plate or the substantial area of the reflecting portion in the first aspect is changed in the main scanning direction.
Since the shading correction in the main scanning direction is performed by changing the reflection area of the directional reflection plate , the original can be uniformly illuminated in the main scanning direction in addition to the effect of the first aspect. Thus, high-definition image reading with a higher S / N ratio can be performed.

The transparent original reading apparatus according to claim 4, imaging
The optical system consists of a single imaging element and the image from that imaging element.
Image dividing means for dividing the
In a transmission original reading apparatus, an image in the main scanning direction transmitted through a document is formed on a plurality of photoelectric conversion elements by the image forming element and the image dividing means, and these are connected to form an image in the main scanning direction. Opposing reflection of the above-mentioned transparent original illumination unit
The plate is elongated in the main scanning direction corresponding to the linear light source, and
And the opposing reflector is used for image division by the image dividing means.
Since the area of the effective reflecting portion of the portion corresponding to the split portion is made wider than the other portions, the illuminance near the split portion can be increased as compared with other regions, and the amount of light near the split portion can be reduced. Since the problem of deterioration can be solved, it is possible to read a high-definition image with a high S / N ratio even in an image division type transparent document reading apparatus.

According to a fifth aspect of the present invention, the shape of the opposing reflecting plate is approximated to an ellipse or a paraboloid corresponding to the shape of the reflector placed on the back of the light source.
Due to the curved shape, the light beam emitted from the light source placed at the focal point of the reflector can be focused again at the focal position of the opposing reflector. In other words, when the opposing reflector was flat, there was a light flux that returned to the light source direction without reaching the diffuser during multiple reflection between the opposing reflectors. Therefore, the light flux from the light source can be efficiently condensed, and the return light to the light source can be eliminated, so that the original can be illuminated more efficiently, so that high-definition image reading with a high S / N ratio is possible. Becomes

According to a sixth aspect of the present invention, there is provided an apparatus for reading a transparent original, wherein the curved reflecting surface of the opposed reflective plate according to the fifth aspect has a focal position on the diffuser surface or closer to the original than the reflector. Since all the light beams reflected by the opposing reflector illuminate the diffuser, more efficient illumination becomes possible, and high-definition image reading with a higher S / N ratio becomes possible. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a transparent document reading apparatus according to an embodiment of the present invention;

FIGS. 2A and 2B are explanatory diagrams showing a light condensing state and a light distribution on a diffusion plate when an installation position of a light source of the transmission original reading apparatus shown in FIG. 1 is shifted from a focal position of a reflector;
Is when the installation position of the light source is displaced after the focal position of the reflector, (b) is when the installation position of the light source matches the focal position of the reflector, and (c) is when the installation position of the light source is more than the focal position of the reflector. It is a figure showing the case where it has shifted ahead.

FIG. 3 is a schematic structural view of a principal part of a transparent document reading apparatus according to an embodiment of the present invention;

FIGS. 4 (a), (b), (c) and (d) are diagrams showing an embodiment of the third embodiment, respectively, and are explanatory diagrams of a shading correction method using an opposed reflecting plate of a transparent original reading apparatus. is there.

FIG. 5 is a schematic configuration diagram showing an example of an image division type transparent original reading apparatus according to claim 4;

FIG. 6 is a diagram showing a shading distribution on a photoelectric conversion element surface of the image division type transparent original reading apparatus shown in FIG.

FIG. 7 is a view showing an embodiment of claim 4, which is an example of an opposed reflector for correcting a steep shading distribution generated by image division of an image division type transparent original reading apparatus;
7A is a diagram illustrating an example in which a shading correction tape is attached to a reflection surface of an opposing reflector, and FIG. 7B is a diagram illustrating an example in which correction is performed based on the shape of the opposing reflector.

FIG. 8 is a schematic view of a main part of a transparent document reading apparatus according to a fifth embodiment of the present invention.

FIG. 9 is a schematic configuration diagram of a transparent document reading apparatus showing an example of a conventional technique.

FIG. 10 is a schematic configuration diagram of a main part of a transparent original reading apparatus showing an example of a conventional technique.

FIG. 11 is an explanatory diagram showing a light condensing state and a light distribution on a diffusion plate when an installation position of a light source of the transmission original reading apparatus shown in FIG. 10 is shifted from a focal position of a reflector;
(A) is when the installation position of the light source is displaced from the focal position of the reflector, (b) is when the installation position of the light source matches the focal position of the reflector, and (c) is when the installation position of the light source is that of the reflector. It is a figure which shows the case where it has shifted | deviated before a focus position, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transmission original illumination unit 2 ... Light source 3 ... Reflector 4 ... Diffusion plate (diffusion light generation means) 5 ... Origin holder 6 ... Transmission original 7 ... Opposing reflection plate 8 ... Cold mirror 9 ... Contact glass 10 ... First mirror 11 ... Second mirror 12 ... Imaging lens 13 ... Photoelectric conversion element 14 ... Cooling fan 15 ... Split prism

Claims (6)

(57) [Claims] A linear light source elongated in the main scanning direction;
To reflect and condense the luminous flux from the light source
And the light flux from the light source and the reflector.
A transparent document illumination unit having diffused light generation means;
And diffused light illumination from the transparent original illumination unit
A document holding means disposed at a position for holding a transparent document;
What is the transparent document illumination unit with the document holding means in between?
Imaging light that is arranged on the opposite side and forms a light beam transmitted through the original
System and photoelectric conversion disposed at an image forming position of the image forming optical system
A transmissive original that illuminates the light flux from the light source from one side of the transmissive original by the above-described transmissive original illumination unit, forms an image of the transmitted light on a photoelectric conversion element by an imaging optical system, and reads the transmissive original. In the reading apparatus, a light source is provided on the diffused light generating means of the transparent original illumination unit.
Beam from the reflector and the reflector
A transmissive original reading apparatus, comprising a pair of opposed reflecting plates for projecting and condensing light . In transparent original reading apparatus according to claim 2 according to claim 1, Rutotomoni provided a gap between the diffused light generating means and the opposing reflecting plate of the transparent original illumination unit, transparent document illumination Yoo
A transparent document reading device, comprising means for cooling the inside of a knit . 3. A transparent original reading apparatus according to claim 1, the opposing reflecting plate of the transparent original illumination unit linear light
Is long in the main scanning direction corresponding to the light source, and the shape of the opposing reflecting plate or the effective area of the reflecting portion is changed in the main scanning direction.
To change the reflection area of the opposing reflector in the main scanning direction.
And a shading correction device for performing shading correction in the main scanning direction. 4. A transparent original reading apparatus according to claim 1, wherein said imaging optical system includes a single imaging element, the imaging
Image division that divides the image from the element into multiple parts in the main scanning direction
And means, the forming an image in the main scanning direction that has been transmitted through the document
Imaged on a plurality of photoelectric conversion elements by the image element and the image splitting means, the transparent original reading device by connecting them to the main scanning direction of the image, the transparent original illumination Uni
The opposing reflector of the unit is long in the main scanning direction corresponding to the linear light source.
And the opposing reflection plate is provided with the image dividing means.
Wherein the area of the effective reflecting portion of the portion corresponding to the image dividing portion is wider than the other portions. 5. The transparent original reading apparatus according to claim 1,
Installed behind the light source of the transparent original illumination unit.
Reflector reflects the divergent light emitted from the light source into parallel light or
An ellipse or paraboloid that converts to convergent light or near
When having a similar curved shape, the shape of the opposing reflector
A transparent original reading apparatus having a curved shape corresponding to the shape of the reflector . In transparent original reading apparatus 6. The method of claim 5, wherein the transparent original reading apparatus being characterized in that set in the original side of the focal point of the diffused light generating means on or diffused light generating means of the opposing reflecting plate.