JP2007150634A - Image reader, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the irradiation efficiency from an exposure lamp on the reading spot of a manuscript, and to reduce the flare light in an image reader for optically reading a manuscript image to convert it into image signals, usable for copying apparatus, scanners, etc. <P>SOLUTION: The image reader has a plurality of exposure lamps 4a, 4b for irradiating the reading spot A of a manuscript with lights, and an imaging device for receiving a reflected light H from the manuscript to convert the image on the manuscript to electric signals. Further, the reader comprises a pair of right and left reflection plates 40, 41 for guiding the irradiating light H to the reading spot A every exposure lamp 4a, 4b between each exposure lamp 4a, 4b and the reading spot A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that is used in a copying machine, a scanner, or the like and optically reads an original image and converts it into an image signal.

As an image reading apparatus such as a copying machine, an image reading apparatus that reads image information of a fixed document by moving an image reading carriage including a light source and a mirror within a predetermined range is widely adopted. In recent years, this type of image reading apparatus has been strongly demanded to improve the condensing efficiency of the exposure lamp as the reading speed increases. In order to cope with this demand, for example, the one described in Patent Document 1 below uses a lens to enhance the light collecting property. In addition, what is disclosed in Patent Document 2 attempts to increase the amount of light by using two lamps having different wavelengths.
Japanese Patent Laid-Open No. 1-142743 JP 2001-333252 A

  However, if the light is condensed by the lens as in the technique described in Patent Document 1, the number of parts increases correspondingly and the structure becomes complicated, so that the manufacturing cost is very expensive. There is a problem of becoming.

  Further, as described in Patent Document 2, when two lamps having different wavelengths are used, the amount of light can be increased, but the efficiency may be reduced. This document does not consider the efficiency. Furthermore, in this type of irradiation device, flare light (stray light) is inevitably generated, and this flare light may interfere with obtaining a clear image. However, this document also considers this flare light. Not done.

  The present invention solves the above-described problem of improving the light collection efficiency. Even when a plurality of lamps are used as the light source, the light collection efficiency can be improved with a relatively simple structure, and flare light is also used. An object of the present invention is to provide an image reading apparatus that can be reduced.

In order to solve the above problems, the present invention employs the following configuration. That is,
According to a first aspect of the present invention, a plurality of exposure lamps for irradiating light to a reading position of a document and reflected light reflected from the document are received through a predetermined optical system to receive an image of the document as an electrical signal. In the image reading apparatus including the image pickup device to be changed to, a pair of left and right reflectors for guiding the irradiation light of the exposure lamp toward the reading position is disposed between each exposure lamp and the reading position. This is an image reading apparatus.

  Next, the second aspect of the present invention is characterized in that the reflectance of the surface of the reflection plate on the side of guiding the irradiation light of the exposure lamp is high, and the reflectance of the back surface is lower than that. 1 is an image reading apparatus according to an embodiment of the present invention.

  According to a third aspect of the present invention, in the image reading apparatus according to the first aspect of the present invention, the reflection plate located on the path side of the reflected light from the document does not block the reflected light from the pair of reflection plates. In this way, the shape is bent toward the side of the irradiation light passage.

Furthermore, a fourth aspect of the present invention uses a fluorescent lamp in which an aperture is formed at a position facing the document as an exposure lamp in the image reading apparatus of the first aspect of the present invention.
According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising any one of the above-described image reading apparatuses and an image forming unit that forms an image on a sheet by using an electric signal from the imaging element. .

The image reading apparatus according to the present invention can efficiently irradiate the reading position with light emitted from the exposure lamp even when a plurality of exposure lamps are used.
The second aspect of the present invention can increase the amount of irradiation light and reduce flare light, so that a high-quality image can be obtained.

  Furthermore, according to the third aspect of the present invention, the reflector can be extended to the vicinity of the reading position, and flare light can be reduced.

The fourth aspect of the present invention uses a fluorescent lamp and is preferable in terms of cost.
Further, the fifth aspect of the present invention can read light efficiently, and as a result, an image of excellent quality can be formed.

Hereinafter, embodiments of the present invention will be specifically described.
FIG. 1 illustrates the configuration of the image reading apparatus of the present invention. FIG. 2 is a reference structural diagram for facilitating the explanation of the features of the present invention. FIGS. 3 (A) and 3 (B) are diagrams of the present invention. It is explanatory drawing of this apparatus. The image reading apparatus 1 includes a machine frame 2 and a contact glass 3 on which an original is placed is attached to the upper surface thereof. Below the contact glass 3, there are provided first and second carriages 5 and 10 that reciprocate within a predetermined stroke.

  On one carriage 5, two exposure lamps 4 a and 4 b made of a fluorescent tube having an aperture 6 that opens at a predetermined angle α (45 degrees in the illustrated example) and a reflection mirror 7 are attached. Yes. As the exposure lamp, it is preferable to use a fluorescent tube in terms of light quantity, cost, design, and the like.

  As shown in FIGS. 2, 3A, and 3B, the pair of exposure lamps 4a and 4b is a document reading position where the aperture portion 6 is positioned at the upper part between the two exposure lamps 4a and 4b. It is fixed by being slightly tilted in opposite directions so as to face toward A. For this reason, the light emitted from the aperture section 6 is condensed at the reading position A on the surface of the document at the center position between the exposure lamps 4a and 4b. In reality, in consideration of mechanical accuracy and the like, it is designed to be in a condensing state with a width of 3 to 4 mm and as uniform and as high an illuminance as possible.

  The second carriage 10 is provided adjacent to the first carriage 5, and reciprocates while cooperating with the carriage 5. The second carriage 10 is for guiding the light reflected from the document to an image sensor CCD 30 described later, and two upper and lower reflection mirrors 11 and 12 are attached.

  The mirror 7 of the first carriage 5 is for reflecting the light reflected from the document in the direction of the reflecting mirror 11 of the second carriage 10. In the illustrated example, the mirror 7 is 45 with respect to the reciprocating direction of the carriage 5. It is provided at an angle. For this reason, the reflected light reflected vertically downward from the document is reflected by the mirror 7 in parallel with the reciprocating direction of the carriage 5 and is incident on the upper reflecting mirror 11 held by the second carriage 10. The light is bent at a right angle from the reflection mirror 11 and enters the lower reflection mirror 12.

  The carriages 5 and 10 are driven by a stepping motor (not shown) provided in the machine casing 2 and reciprocate at a predetermined speed in the direction of arrow B along the contact glass 3 of FIG. By this movement, the document surface is scanned with the irradiation light from the exposure lamps 4a and 4b.

  A lens unit 20 and an image sensor (CCD) 30 are provided in series near the end of the machine frame 2 outside the moving range of the carriages 5 and 10. The light reflected by the reflecting mirror 12 is collected by the lens unit 20 and enters the image pickup device 30, where it is converted into an electrical signal, and is not shown in the figure. The image signal is output to the control unit.

  Further, in the image reading apparatus 1, a pair of left and right reflecting plates 40 and 41 are provided around the exposure lamps 4a and 4b as a condensing unit for irradiation light. These reflectors 40 and 41 have a strip shape, and extend along the longitudinal direction of the cylindrical exposure lamps 4a and 4b so as to cover the entire aperture 6 of the exposure lamps 4a and 4b from both sides. Is provided.

  As shown in FIGS. 3 (A) and 3 (B), the reflectors 40 and 41 are provided so that the base portions 40a and 41a sandwich the aperture portion 6 of the exposure lamps 4a and 4b, and the tip ends thereof. The portions 40b and 41b are inclined so as to become narrower as the distance D between the reflecting plates 40 and 41 approaches the reading position A, so that the front end openings of the reflecting plates 40 and 41 face the document reading position A. Is provided. The interval D is set to a size that can irradiate the reading position A with sufficient light.

  The reflectors 40 and 41 are made of a metal material such as high-luminance aluminum, for example, and the inner surfaces 40c and 41c sandwiching the aperture portion 6 of the exposure lamps 4a and 4b have a high reflectance, and the outer surfaces 40d and 41d are reflected. Designed to be lower rates.

  The reason why the reflectivity of the inner surfaces 40c and 41c is increased is to increase the amount of light with respect to the original to increase the irradiation efficiency. This is to reduce further adverse effects. Accordingly, it is desirable that the reflectances of the inner surfaces 40c and 41c be as high as possible and the reflectances of the outer surfaces 40d and 41d be as low as possible. For example, it is painted black.

  The image reading apparatus 1 places an original on the contact glass 3 and reciprocates the carriages 5 and 10 at a predetermined speed, and emits light emitted from the aperture 6 of the exposure lamps 4a and 4b. Illuminate A. The reflected light H reflected from the reading position A of the original travels along the outer surfaces 40d and 40d of the inner reflection plates 40 and 40 and enters the mirror 7, from which the reflection mirrors 11 and 12 and the lens unit 20 are passed. Then, the light enters the image sensor 30. The image sensor 30 converts light into an image signal.

  FIG. 2 is a reference explanatory diagram in the case where the reflectors 40 and 41 are not provided as in the present invention. The irradiation light S emitted from the exposure lamps 4a and 4b is dispersed over a wide range and irradiated onto the original. . Although this irradiation light S is also incident on the reading position A of the document, most of the irradiation light is irradiated to a place other than the reading position A and is reflected from there to become flare light F. For this reason, the irradiation efficiency at the reading position A is not only lowered, but the flare light F adversely affects the image.

  On the other hand, in the present invention, since the reflection plates 40 and 41 are provided so as to sandwich the aperture 6 of the exposure lamps 4a and 4b, the light from the exposure lamps 4a and 4b is condensed by the reflection plates 40 and 41. In most cases, the reading position A is irradiated. For this reason, the irradiation efficiency is greatly improved.

  Further, since the irradiation light is guided by the reflectors 40 and 41, the amount of light that becomes flare light is small, and a high-quality image can be obtained in this respect as well. Note that by reducing the reflectance of the outer surfaces 40d and 41d of the reflecting plates 40 and 41, flare light is reduced, so that a higher quality image can be obtained.

Next, the embodiment shown in FIG. 4 is slightly different from the above. In the above embodiment, the reflectors 40 and 41 are both linear in cross section. The cross-sectional shape of the reflector 40 located on the side) is not a straight line but a bent shape.
That is, the base portion 40a of the reflecting plate 40 is positioned so as to sandwich the aperture portion 6 together with the reflecting plate 41 on the opposite side, but the portion 40b on the tip side from the intermediate portion is moved from the exposure lamps 4a and 4b to the reading position A. The shape is bent toward the side of the passage of emitted light.
For this reason, the portion sandwiched between the reflecting plates 40 and 41 is considerably narrower at the tip side compared to the case where the cross section is linear, and has a shape that can easily guide the irradiation light to the reading position A in a concentrated manner. ing.

  In addition, since the distal end portion 40b is bent toward the irradiation passage side, depending on the design, the reflection plate 40 is extended to the vicinity of the reading position A while not blocking the reflected light after being reflected at the reading position A. be able to. Therefore, the light collection efficiency at the document reading position A can be further improved.

  Further, the outer surface 40 d of the bent portion 40 b on the front end side of the reflecting plate 40 is substantially parallel to a line connecting the document reading position A and the center of the mirror 7. By doing so, the reflecting plate 40 is unlikely to interfere with the reflected light H, so that the reflected light H traveling straight from the reading position A toward the mirror 7 is not disturbed by the reflecting plate 40. The inner reflector 40 may have an elliptical curved shape instead of the bent shape as described above.

As described above, the image reading apparatus 1 uses a fluorescent tube with an aperture as the two exposure lamps 4a and 4b, and irradiates the original with the two exposure lamps. However, since the pair of reflectors 40 and 41 for guiding the light emitted from the exposure lamps 4a and 4b toward the document reading position A are provided, the light collection efficiency is greatly improved.
Since only a pair of reflectors 40 and 41 is provided in the aperture portion of each exposure lamp, the structure is simple and the cost does not increase so much.

In the above embodiment, an example in which two exposure lamps are used has been described. However, it is also effective to provide such a reflector in the same manner when two or more exposure lamps are used. Needless to say.
The image reading apparatus of the present invention can be incorporated into an image forming apparatus such as a copying machine provided with an image forming unit for forming an image on a sheet by using an electric signal from the image pickup device.

  The image reading apparatus according to the present invention can be used as an image reading apparatus such as an electrophotographic copying machine, printer, or facsimile.

1 is a front view schematically illustrating a configuration of an image reading apparatus according to an embodiment of the present invention. It is sectional drawing of the exposure lamp arrangement | positioning part used as the reference for demonstrating this invention. FIG. 2A is a cross-sectional view of a main part of an image reading apparatus according to an embodiment of the present invention. FIG. 4B is a cross-sectional view of the reflecting plate in the main part of the image reading apparatus in FIG. It is sectional drawing of the principal part showing other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image reader 2 Machine frame 3 Contact glass 4a, 4b Exposure lamp 5 Carriage 7 Reflection mirror 10 Carriage 11 Reflection mirror 12 Reflection mirror 20 Lens unit 30 Imaging element 40 Reflection plate 41 Reflection plate

Claims (5)

A plurality of exposure lamps for irradiating light to a reading position of the document; and an image sensor for receiving reflected light reflected from the document through a predetermined optical system and converting an image of the document into an electrical signal. In the image reading apparatus,
An image reading apparatus, wherein a pair of left and right reflecting plates that guide irradiation light of the exposure lamp toward the reading position are disposed between the exposure lamps and the reading position.   2. The image reading apparatus according to claim 1, wherein the reflecting plate has a high reflectance on a surface that guides the irradiation light of the exposure lamp, and has a lower reflectance on the back surface thereof.   The reflective plate located on the path side of the reflected light from the original among the pair of reflectors has a shape bent toward the path of the irradiation light so as not to block the reflected light. The image reading apparatus according to 1.   The image reading apparatus according to claim 1, wherein the exposure lamp is a fluorescent lamp in which an aperture is formed at a position facing the document.   An image forming apparatus comprising: the image reading apparatus according to claim 1; and an image forming unit that forms an image on a sheet by using an electric signal from the image sensor.

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