JP2009094722A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image reader capable of increasing a light emission area and an original lighting light quantity by efficiently collecting lights while using a power saving, low heat generating electroluminescent device as a light source. <P>SOLUTION: The tight adhesive image reader for reading lights reflected by a document D line by line with a photoelectric transducer 16 via a real scale image forming lens array 18 uses electroluminescent device 20 as a light source for lighting the document. The electroluminescent device 20 is disposed on the backside of a board 15 of the photoelectric transducer 16 and an emitted light is led to a read position R by a light collecting means 30 comprising a reflection plate or a light guide bypassing both sides of the photoelectric transducer 16. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image reading apparatus, and more particularly to a contact-type image reading apparatus that optically reads a document image.

  In recent years, as an image reading apparatus mounted on a copying machine or a printer, or used as an image input device to a personal computer or the like, reflected light from an original is moved while moving the original or a reading mechanism relatively in one direction, etc. An apparatus configured to form an image on a photoelectric conversion element (CCD line sensor) via a double imaging element is known.

  Conventionally, fluorescent lamps and halogen lamps have been mainly used as light sources for illuminating documents. Recently, however, electroluminescent elements have low power consumption and low heat generation, and the size and height of readers have been reduced. It is attracting attention as a light source that can be used. However, since the electroluminescence element has surface emission and the light amount itself is small, and the contact-type image reading apparatus has a small space around the photoelectric conversion element, it is necessary to efficiently collect light at the reading position. In addition, it is necessary to consider that the illumination light does not cause shadows due to the unevenness of the document (particularly the end surface of the document).

Conventionally, an electroluminescence element is used as a light source of a contact-type image reading apparatus, and Patent Document 1 describes a configuration in which an electroluminescence element is attached to a transparent plate to illuminate a document. Patent Document 2 describes a configuration in which the electroluminescence element is disposed obliquely with respect to the document placement glass. However, these documents 1 and 2 do not mention that the electroluminescence element emits light in an area as large as possible and efficiently condenses the light to the reading position.
JP 2001-28665 A JP-A-5-336310

  Accordingly, an object of the present invention is to provide a contact type that can increase the light emission area and increase the amount of light emitted from the original by efficiently condensing while using an electroluminescent element with low power consumption and low heat generation as a light source. An image reading apparatus is provided.

In order to achieve the above object, the present invention provides:
In a contact-type image reading apparatus that optically reads reflected light from an original while moving the original or a reading mechanism relatively in one direction.
An electroluminescence element for illuminating an original, a photoelectric conversion element on which reflected light from the original is incident, an equal-magnification imaging element for guiding the reflected light from the original to the photoelectric conversion element, and the electroluminescence element Condensing means for guiding the light emitted from the reading position to the reading position,
The electroluminescence element is disposed on the side opposite to the reading position with respect to the photoelectric conversion element and substantially parallel to the substrate of the photoelectric conversion element,
The condensing means guides light emitted from the electroluminescence element to a reading position by wrapping around both sides of the photoelectric conversion element,
It is characterized by.

  In the image reading apparatus according to the present invention, since the electroluminescence element is arranged substantially in parallel with the substrate of the photoelectric conversion element, a large light emission area can be secured as efficiently as possible by utilizing the area of the substrate. Further, since the emitted light is guided to the reading position by wrapping around both sides of the photoelectric conversion element by the condensing means, the reading position can be efficiently illuminated.

  In the image reading apparatus according to the present invention, if the light condensing means is composed of a reflecting plate, it can be manufactured at low cost. If the light condensing means is a light guide, the light guide efficiency is further improved.

  Moreover, the intensity | strength which the light radiated | emitted from the electroluminescent element irradiates a reading position may differ in the both sides of a photoelectric conversion element. For example, the irradiation intensity on both sides of the photoelectric conversion element can be made different by disposing the electroluminescence elements in a direction parallel to the scanning movement direction. Increasing the irradiation intensity from the direction in which the shadow of the document can be made can eliminate the problem of reading such a shadow as an image.

  If the electroluminescent device is arranged so that light is emitted to the side opposite to the reading position, the circuit for emitting light can be integrated with the substrate of the photoelectric conversion device, saving space and the width of the electroluminescent device. Can be expanded up to the width of the substrate of the photoelectric conversion element to ensure the amount of light emission.

  On the other hand, if the electroluminescence element is arranged so that light is emitted to the reading position side, a sufficient amount of light can be secured by making the width dimension of the element larger than the width dimension of the substrate of the photoelectric conversion element. .

  Embodiments of an image reading apparatus according to the present invention will be described below with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same member and part, and the overlapping description is abbreviate | omitted.

(Schematic configuration of image reading apparatus, see FIG. 1)
FIG. 1 shows a schematic configuration of an image reading apparatus according to the present invention. The image reading apparatus 1 is a contact type that reads an image of a document D placed on a platen glass 10 at an equal magnification, and is arranged so that a slider 11 can move at a predetermined speed in the direction of arrow A directly below the platen glass 10. Has been. Hereinafter, the arrow A direction is referred to as a scanning movement direction. The document image is read with a direction B orthogonal to the scanning movement direction A as one line. The reading line direction B is also referred to as a main scanning direction. The slider 11 moves from the reading start position X1 to the end position X2, reads the image, and then returns to the start position X1. In the slider 11, reading mechanisms such as a photoelectric conversion element 16, an electroluminescence element 20, and a light collecting means 30 described below with reference to FIGS. 2 to 4 are accommodated.

(See the first embodiment, FIG. 2)
FIG. 2 shows a first embodiment of the image reading apparatus. A reading mechanism is accommodated in the slider 11, that is, a photoelectric conversion element 16 (CCD line sensor) mounted on the substrate 15, an equal magnification imaging lens array 18, and an electroluminescence element 20 (hereinafter referred to as an EL element). The condensing means 30 is accommodated.

  In the EL element 20, a transparent organic (or inorganic) light emitting layer is sealed with a transparent glass material provided with a transparent electrode such as indium-tin oxide (ITO). Is shown. The EL element 20 is disposed on the side opposite to the reading position R with respect to the photoelectric conversion element 16 and in parallel with the substrate 15. More specifically, the EL element 20 is disposed on the back side of the substrate 15 so as to radiate the light emitting portion 21 to the side opposite to the reading position R.

  The light condensing means 30 is constituted by a reflecting plate having a mirror surface on the inside, and as indicated by a dotted arrow, the light emitted from the EL element 20 wraps around both sides of the photoelectric conversion element 16 to read the reading position R. Lead to. The reflected light from the document D enters the equal magnification imaging lens array 18 and forms an image on the photoelectric conversion element 16.

  Incidentally, members accommodated in the slider 11 such as the photoelectric conversion element 16, the EL element 20, and the light condensing means 30 extend along the main scanning direction B orthogonal to the scanning movement direction A. Further, these members have a symmetrical shape parallel to the scanning movement direction A with respect to the center line C. In this specification, the “side”, “width” or “width dimension” of these members relates to a direction parallel to the scanning movement direction A.

  In the first embodiment configured as described above, since the EL element 20 is arranged in parallel to the substrate 15 of the photoelectric conversion element 16, a large light emitting area is secured as efficiently as possible by utilizing the area of the substrate 15. be able to. Further, since the emitted light is guided around the both sides of the photoelectric conversion element 16 by the condensing means 30 and guided to the reading position R, the reading position R can be efficiently illuminated. Moreover, since the light condensing means 30 is composed of a reflecting plate, it can be manufactured at low cost.

  Further, since the EL element 20 is arranged so that the light is emitted to the side opposite to the reading position R, a circuit for causing light emission can be provided integrally on the substrate 15 of the photoelectric conversion element 16. Space saving. In the first embodiment, making the width dimension of the EL element 20 larger than the width dimension of the substrate 15 leads to an increase in the size of the slider 11 and lowers the light utilization efficiency. The width dimension may be smaller than the width dimension of the substrate 15, and a large light emission amount can be ensured by expanding the width dimension to the maximum width dimension of the substrate 15.

  In the first embodiment, the reading mechanism is symmetrical with respect to the center line C, and the intensity at which the light emitted from the EL element 20 irradiates the reading position R is equal to the left and right. In this case, by slightly shifting the EL element 20 in the left-right direction, the irradiation intensity to the reading position R can be varied between the left and right (both sides parallel to the scanning movement direction A). In other words, by moving the position of the EL element 20 in a direction parallel to the scanning movement direction A, the amount of light irradiated from the left and right can be finely adjusted, and the light intensity on both sides of the photoelectric conversion element 16 is dared. May be different. Increasing the irradiation intensity from the direction in which the shadow of the document D can be made can solve the problem that such a shadow is read as an image.

(Refer to the second embodiment, FIG. 3)
FIG. 3 shows a second embodiment of the image reading apparatus. In this second embodiment, the width of the EL element 20 is made smaller than the width of the substrate 15, and the EL element 20 is arranged slightly shifted in the scanning movement direction A from the center line C. The configuration is the same as in the first embodiment.

  An original positioning scale 12 is installed on the reading start position X1 of the platen glass 10. When the original D is positioned on the scale 12 and placed on the glass 10, the shadow of the scale 12 may be read as an image. is there. However, in the second embodiment, since the intensity of the irradiation light L1 from the scanning movement direction A side is larger than the intensity of the irradiation light L2 from the return direction side, the generation of shadows by the scale 12 can be eliminated. Other functions and effects of the second embodiment are the same as those of the first embodiment.

(Refer to the third embodiment, FIG. 4)
FIG. 4 shows a third embodiment of the image reading apparatus. In this third embodiment, the EL element 20 is disposed slightly away from the substrate 15 on the side opposite to the reading position R with respect to the photoelectric conversion element 16 and in parallel with the substrate 15, and the light is read. The light emitting unit 21 was arranged upward so as to radiate to the position R side. Further, the light collecting means 30 is constituted by a light guide. Other configurations are the same as those of the first embodiment.

  The light condensing means (light guide) 30 covers the light emitting portion 21 of the EL element 20, and condenses the light emitted from the EL element 20 around the photoelectric conversion element 16 at the reading position R. Thus, if a light guide is used, the light guide efficiency is further improved. Further, since the EL element 20 is arranged so that light is emitted to the reading position R side, a sufficient amount of light can be obtained by making the width dimension of the EL element 20 larger than the width dimension of the substrate 15 of the photoelectric conversion element 16. Can be secured. Other functions and effects of the third embodiment are the same as those of the first embodiment.

(Other examples)
The image reading apparatus according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist thereof.

  For example, as an image reading apparatus to which the present invention is applied, in addition to a method in which a reading mechanism moves to read an image of a stationary document, an image is conveyed by conveying a document at a predetermined speed directly above a reading mechanism that is stationary at a predetermined position. The sheet-through method may be used. Further, the specific configuration and shape of the light collecting means are arbitrary.

1 is a perspective view showing a schematic configuration of an image reading apparatus according to the present invention. It is sectional drawing which shows 1st Example. It is sectional drawing which shows 2nd Example. It is sectional drawing which shows 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image reader 10 ... Platen glass 15 ... Board | substrate 16 ... Photoelectric conversion element 18 ... Same magnification imaging lens array 20 ... Electroluminescence element 21 ... Light emission part 30 ... Condensing means A ... Scanning movement direction B ... Main scanning direction D ... Original R ... Reading position

Claims (7)

In a contact-type image reading apparatus that optically reads reflected light from an original while moving the original or a reading mechanism relatively in one direction.
An electroluminescence element for illuminating an original, a photoelectric conversion element on which reflected light from the original is incident, an equal-magnification imaging element for guiding the reflected light from the original to the photoelectric conversion element, and the electroluminescence element Condensing means for guiding the light emitted from the reading position to the reading position,
The electroluminescence element is disposed on the side opposite to the reading position with respect to the photoelectric conversion element and substantially parallel to the substrate of the photoelectric conversion element,
The condensing means guides light emitted from the electroluminescence element to a reading position by wrapping around both sides of the photoelectric conversion element,
An image reading apparatus.   The image reading apparatus according to claim 1, wherein the condensing unit is a reflecting plate.   The image reading apparatus according to claim 1, wherein the light collecting unit is a light guide.   4. The image reading according to claim 1, wherein the intensity at which the light emitted from the electroluminescence element illuminates the reading position is different on both sides of the photoelectric conversion element. 5. apparatus.   The image reading apparatus according to claim 4, wherein the electroluminescence elements are arranged so as to be shifted in a direction parallel to a scanning movement direction.   6. The electroluminescence device according to claim 1, wherein the electroluminescence device emits light to the side opposite to the reading position, and the width of the device is equal to or smaller than the width of the substrate of the photoelectric conversion device. The image reading apparatus according to any one of the above.   6. The electroluminescent device according to claim 1, wherein the electroluminescent device emits light toward the reading position, and the width of the device is equal to or larger than the width of the substrate of the photoelectric conversion device. The image reading apparatus described.

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