JP5110044B2 - Image reader - Google Patents

Description

  The present invention relates to an image reading apparatus, and more particularly to an image reading apparatus that optically reads reflected light from a document image.

  In general, an image reading apparatus called a scanner moves a reading system including a light source arranged one-dimensionally and a reading object such as a document in a direction orthogonal to the one-dimensional direction. The image is read. Conventionally, many fluorescent lamps have been used as this type of light source, but in recent years, the use of LEDs has been studied. However, unlike a fluorescent lamp, an LED is a point light source. Therefore, in order to obtain a one-dimensional (line-shaped) light distribution necessary for scanning, the LED is changed to a line shape using a light guide. Alternatively, it is necessary to form a plurality of lines in a one-dimensional direction on the substrate.

  In addition, in an image reading apparatus, it is required to irradiate an object to be read from both sides in a scanning direction in order to read a three-dimensional part without shadow. In conventional illumination systems using fluorescent lamps, instead of illuminating from both sides using two fluorescent lamps, a single fluorescent lamp and a reflecting mirror facing the fluorescent lamp are used for cost reduction. However, when an LED is used as a light source, the LED has a strong directivity, so that it cannot be used with a wide opening angle like a fluorescent lamp, and it is difficult to irradiate light from both sides in the scanning direction.

  Therefore, Patent Document 1 proposes to arrange LEDs on both sides in the scanning direction and irradiate the reading object from both sides. Further, in Patent Document 2, a light collector is interposed between the LED and the reading object, a part of the light traveling toward the reading object is reflected, and the light reflected by the reflecting mirror arranged oppositely is read. Proposes to irradiate an object.

  However, disposing LEDs on both sides as in the former inevitably increases the cost because the required substrate becomes larger and wiring becomes complicated. When the light is branched to both sides by the concentrator interposed as in the latter, light irradiation from both sides can be realized, but it is difficult to adjust the light quantity balance on both sides.

JP 2004-170858 A JP 2005-102112 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image reading apparatus that can irradiate a reading object efficiently and in a balanced manner from both sides with a low cost and a simple configuration.

In order to achieve the above object, an image reading apparatus according to the first embodiment of the present invention is provided.
In an image reading apparatus that irradiates a reading object with light emitted from a plurality of light emitting elements juxtaposed in the main scanning direction and optically reads the reflected light,
A single substrate,
A first light emitting element disposed at an end of the substrate;
A second light emitting element disposed at a place other than the end of the substrate;
A light guide that linearly guides light emitted from the first light emitting element in the main scanning direction and irradiates the reading object;
A reflective member that is provided on the surface of the light guide and reflects light emitted from the second light emitting element;
With
The light reflected by the reflecting member is irradiated from the opposite side in the sub-scanning direction to the light emitted from the first light emitting element to the reading object;
It is characterized by.

  In the image reading apparatus according to the first embodiment, the light emitted from the first light emitting element passes through the light guide, and the light emitted from the second light emitting element passes through the reflecting member provided on the surface of the light guide. Since the reading object is irradiated from both sides in the sub-scanning direction (scanning direction), it is possible to read without making a shadow even in a three-dimensional part. Moreover, the balance of the irradiation light quantity from both sides can be adjusted by changing the ratio of the arrangement number of the first and second light emitting elements. In addition, since the first and second light-emitting elements are arranged on a single substrate, wiring and the like are simplified, and cost can be reduced.

The image reading apparatus according to the second aspect of the present invention is:
In an image reading apparatus that irradiates a reading object with light emitted from a plurality of light emitting elements juxtaposed in the main scanning direction and optically reads the reflected light,
A single substrate,
A plurality of light emitting elements arranged in the main scanning direction on the substrate;
A light guide disposed directly above the light emitting element;
A reflecting member that reflects light toward the reading object;
With
The light guide is made of a transparent material, has a plane that is not parallel to the substrate, and irradiates the reading object with the first light transmitted through the plane out of the light emitted from the light emitting element. And the second light reflected by the plane faces the reflecting member,
Irradiating the reading object from both sides facing each other in the sub-scanning direction, respectively, the first light and the second light;
It is characterized by.

  In the image reading apparatus according to the second embodiment, of the light emitted from the light emitting element, the first light transmitted through the plane of the light guide irradiates the reading object from the light guide, and the plane of the light guide Since the second light reflected by the beam irradiates the reading object through the reflecting member, and the first light and the second light irradiate the reading object from both sides in the sub-scanning direction (scanning direction), respectively, Even in the target area, it can be read without creating a shadow. Moreover, the balance of the irradiation light quantity from both sides can be adjusted by changing the light emission ratio of the first and second lights. In addition, since the light-emitting elements are arranged on a single substrate, wiring and the like are simplified, and cost can be reduced.

  According to the present invention, since the reading object is irradiated from both sides in the sub-scanning direction, the reading object can be efficiently and balancedly irradiated from both sides, and reading can be performed without creating a shadow even in a three-dimensional part. It becomes possible. In addition, since the light-emitting elements are arranged on a single substrate, wiring and the like are simplified, and cost can be reduced.

It is a schematic block diagram which shows the principal part of the image reading apparatus which is 1st Example. It is a perspective view which shows the light source part of the said 1st Example. It is a perspective view which shows the light guide which comprises the said 1st Example. It is a schematic block diagram which shows the principal part of the image reading apparatus which is 2nd Example. It is a perspective view which shows the light source part of the said 2nd Example. It is a perspective view which shows the light source part of the image reader which is 3rd Example.

  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 drawing, the same code | symbol is attached | subjected regarding the same member and part, and the overlapping description is abbreviate | omitted.

(Refer 1st Example and FIGS. 1-3)
As shown in FIGS. 1 and 2, the image reading apparatus according to the first embodiment has a plurality of first and second LEDs (light emitting diodes) 11 and 12 on the upper surface of a single substrate 20 in the main scanning direction. A light guide 30 and a reflecting member 39 are provided in parallel with A. Each of the first and second LEDs 11 and 12 is a top-illuminated type (top view) type, one first LED 11 is disposed at each end of the substrate 20, and the second LED 12 is the first LED 11. A plurality of them are arranged at equal intervals between them.

  A light guide 30 made of a transparent material is disposed immediately above the LEDs 11 and 12, and the light B1 emitted from the first LED 11 enters the inside from the end 30a of the light guide 30 and enters the end inclined surface 30b. Total reflection is made, and the traveling direction is changed to the main scanning direction A. Further, most of the light B1 is reflected / diffused by a plurality of minute projections provided in the main scanning direction A on the inclined surface 30c of the light guide 30, and is condensed into the light B1 ′ by changing the traveling direction, and the platen glass 40 The document D placed on the top is irradiated from the lower left direction in FIG. A region where the minute protrusions are formed is hatched in FIG.

  Further, a reflective tape 32 is bonded to the inclined surface 30d of the light guide 30, and the light B2 emitted from the second LED 12 is reflected by the reflective tape 32, and further reflected by the reflective member 39 to form the document D. Irradiate from the lower right in FIG.

  The substrate 20 is installed in parallel with the platen glass 40 and has a length that sufficiently covers the width of the document D in the main scanning direction A in which the LEDs 11 and 12 are arranged. Further, the LEDs 11 and 12 are used in such a number that the light quantity necessary for optically reading the document image can be obtained. The light radiated from the LEDs 11 and 12 and reflected by the document D is reflected by the mirror 45, read by the image sensor 47 such as a CCD through the imaging lens 46, and processed as image information. At the time of reading, the illumination system including the LEDs 11 and 12 moves in the sub-scanning direction B at a predetermined speed.

  In the first embodiment, the light emitted from the first LED 11 passes through the light guide 30, and the light emitted from the second LED 12 passes through the reflective tape 32 and the reflective member 39 to sub-scan the document D, respectively. Irradiation can be efficiently performed from both sides in the direction B, and an image can be read without making a shadow even if the document D has a step at the reading position C. In addition, since the first and second LEDs 11 and 12 are disposed on the single substrate 20, wiring and the like are simplified, and the cost can be reduced. Furthermore, by using the light guide 30 having the light guide function and the light collection function, the light emitted from the first LED 11 can be condensed at the reading position C, and the light use efficiency can be increased.

  Further, since the LEDs 11 and 12 are point light sources, unevenness in the amount of light tends to occur in the arrangement direction. However, when the light guide 30, the reflection tape 32, and the reflection member 39 are used as in the first embodiment, the distance from the LEDs 11 and 12 to the original D is increased, and the amount of light in the main scanning direction A is uneven due to the diffusion of light. Is reduced. Furthermore, by changing the ratio of the number of the first LEDs 11 and the second LEDs 12 arranged, the illumination ratio from the left and right direction with respect to the document D can be freely changed, and the ideal left and right balance is close to 1: 1. Is easy.

(Refer to the second embodiment, FIGS. 4 and 5)
The image reading apparatus according to the second embodiment basically has the same configuration as that of the first embodiment. As shown in FIGS. 4 and 5, a top-view type LED 11 is mounted on the substrate 20. The light guide 35 and the reflection member 39 are provided in parallel in the main scanning direction A.

  The light guide 35 is made of a transparent material and has flat surfaces 35 a and 35 b that are not parallel to the substrate 20. The light B1 emitted from the LED 11 irradiates the flat surface 35a, and is divided into transmitted light and reflected light according to the well-known Snell's law on the flat surface 35a. The transmitted light that has entered the inside of the light guide 35 is further reflected from the flat surface 35b, and is collected and applied to the original D placed on the platen glass 40 from the lower left direction in FIG. The reflected light on the plane 35b is further reflected by the reflecting member 39 to irradiate the original D from the lower right in FIG.

  In the second embodiment, of the light emitted from the LED 11, the first light transmitted through the plane 35 a irradiates the document D from the light guide 35, and the second light reflected by the plane 35 a is a reflecting member. 39, the first light and the second light can efficiently irradiate the original D from both sides in the sub-scanning direction B, and there is a step in the original D at the reading position C. The image can be read without creating a shadow. In addition, since the LEDs 11 are arranged on the single substrate 20, wiring and the like are simplified, and the cost can be reduced. Furthermore, since the optical path from the LED 11 to the reading position C becomes longer, unevenness in the amount of light in the main scanning direction A is reduced by light diffusion. Further, by changing the ratio of the transmitted light and the reflected light on the plane 35a, the illumination ratio from the left and right direction with respect to the document D can be freely changed, and the ideal left and right balance is brought close to 1: 1. Is easy.

  In the second embodiment, when a reflective tape is provided outside the flat surface 35b of the light guide 35, the reflection efficiency is improved and the amount of light irradiating the document D is increased.

(Refer to the third embodiment, FIG. 6)
The image reading apparatus according to the third embodiment basically uses a light guide 35 as in the second embodiment, and as shown in FIG. ) Type first LEDs 11 and side-illuminated (side view) type second LEDs 12 are alternately arranged in the main scanning direction A.

  The light B1 radiated from the first LED 11 is divided into transmitted light and reflected light on the plane 35a of the light guide 35, and the document is viewed from both sides facing the sub-scanning direction B as in the second embodiment. Irradiate. On the other hand, the light B2 emitted from the second LED 12 is directly reflected by the reflecting member 39 and irradiates the original.

  In the third embodiment, since the light from the second LED 12 directly irradiates the original through the reflecting member 39, the amount of light irradiating the original from the reflecting member 39 can be increased. By adjusting the number of the first and second LEDs 11 and 12 arranged, it is easy to bring the right and left light quantity balance closer to an ideal 1: 1.

(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.

  In particular, the shape and arrangement of the light guide and the reflecting member are arbitrary. The position of the image reading device and the platen glass may be fixed, and the image may be read while conveying the document in the sub-scanning direction at a predetermined speed. Further, instead of the top-illuminated LED, a top-illuminated organic EL (electroluminescence) element may be arranged.

  As described above, the present invention is useful for an image reading apparatus, and is particularly excellent in that light can be efficiently and balancedly irradiated from both sides to an object to be read with a low cost and a simple configuration.

11,12 ... LED
DESCRIPTION OF SYMBOLS 20 ... Board | substrate 30,35 ... Light guide 35a ... Plane 32 ... Reflective tape 39 ... Reflective member 40 ... Platen glass A ... Main scanning direction B ... Sub-scanning direction D ... Original

Claims (4)

In an image reading apparatus that irradiates a reading object with light emitted from a plurality of light emitting elements juxtaposed in the main scanning direction and optically reads the reflected light,
A single substrate,
A first light emitting element disposed at an end of the substrate;
A second light emitting element disposed at a place other than the end of the substrate;
A light guide that linearly guides light emitted from the first light emitting element in the main scanning direction and irradiates the reading object;
A reflective member that is provided on the surface of the light guide and reflects light emitted from the second light emitting element;
With
The light reflected by the reflecting member is irradiated from the opposite side in the sub-scanning direction to the light emitted from the first light emitting element to the reading object;
An image reading apparatus.   The image reading apparatus according to claim 1, further comprising another reflecting member that reflects the light reflected by the reflecting member with respect to the reading object. In an image reading apparatus that irradiates a reading object with light emitted from a plurality of light emitting elements juxtaposed in the main scanning direction and optically reads the reflected light,
A single substrate,
A plurality of light emitting elements arranged in the main scanning direction on the substrate;
A light guide disposed directly above the light emitting element;
A reflecting member that reflects light toward the reading object;
With
The light guide is made of a transparent material, has a plane that is not parallel to the substrate, and irradiates the reading object with the first light transmitted through the plane out of the light emitted from the light emitting element. And the second light reflected by the plane faces the reflecting member,
Irradiating the reading object from both sides facing each other in the sub-scanning direction, respectively, the first light and the second light;
An image reading apparatus.   The light emitting element includes a first light emitting element that emits light in a direction perpendicular to the plane of the substrate, and a second light emitting element that emits light in a direction parallel to the plane of the substrate. The image reading apparatus according to claim 3, wherein:

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