JP5678638B2 - Image reading illumination device and image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus used for a copying machine, a facsimile machine, an image scanner, and the like, and an image reading illumination apparatus for irradiating light to an image reading position in the image reading apparatus. In particular, when the light emitted from the point light source provided at the longitudinal end portion of the light guide is irradiated to the image reading position through the light guide, the light emitted from the point light source to the light guide is image read. It is characterized in that the position is simply and appropriately irradiated from both sides.

  Conventionally, in a copying machine, a facsimile, an image scanner, etc., an object to be read such as a document set on a document reading table by irradiating an image reading position with light from an image reading illumination device provided in the image reading device. The image information in is read.

  Here, as an image reading illumination device, conventionally, an illumination device using a fluorescent lamp as a light source is generally used, and when there is a stepped portion or the like on a reading object such as a book. In order to prevent the occurrence of a shadowed part, a reflecting member is provided on the opposite side of the image reading position so as to face the fluorescent lamp, and the light from the fluorescent lamp is irradiated from one side of the image reading position. A lamp is used in which light from a lamp is reflected by a reflecting member so that light is irradiated also from the opposite side of the image reading position.

  However, when a fluorescent lamp is used in the image reading illumination device, there are problems that the power consumption increases, the running cost increases, and the life as a light source is short.

  For this reason, in recent years, an LED light source has been proposed as the light source of the image reading illumination device.

  For example, in Patent Document 1, LED arrays in which a plurality of LED light sources are arranged are arranged on both sides in the sub-scanning direction with respect to the image reading position, and light is emitted from the LED arrays on both sides with respect to the image reading position. It has been proposed in However, when a large number of LED light sources are provided in this way, there is a problem that the cost is high and the power consumption is high and the running cost is high.

  Further, in Patent Document 2, a light guide that guides light emitted from an LED light source is provided in a folded shape through a propagation portion, and the both sides of the image reading position are provided by the light guide provided in the folded shape in this way. Have been proposed to emit light. However, when the light emitted from the LED light source is emitted from the folded light guide through the propagation part, the light emitted from the LED light source is emitted from the light guide directly guided. The intensity difference between the emitted light and the light emitted from the light guide through which the light is guided through the propagation part increases, and the color reproducibility of the read image also deteriorates due to a difference in chromaticity. There was a problem of becoming.

  In Patent Document 3, two types of light turning surfaces are provided that reflect light along the longitudinal direction of the light guide that guides the light emitted from the LED light source, and the light guide and the image reading position are interposed. A reflecting mirror is provided at the opposite position, and one light redirected at the light redirecting surface is emitted from the light guide to one side of the image reading position, while the other light redirected at the light redirecting surface. Has been proposed in which light is guided from a light guide to a reflecting mirror, and light reflected by the reflecting mirror is emitted to the opposite side of the image reading position. However, adjusting the amount of light emitted from the light guide to one side of the image reading position and the amount of light guided from the light guide to the reflecting mirror by the two types of light deflecting surfaces in this way is balanced. In order to prevent the light emitted from the LED light source from passing through the light guide to the opposite side and wasting the emitted light, the height of these light turning surfaces is appropriately adjusted. There is a problem that it is difficult to make adjustments.

JP 2004-170858 A JP 2002-185708 A JP 2008-216409 A

  An object of the present invention is to solve the above-described various problems when reading image information on an object to be read such as a document by irradiating an image reading position with light from an image reading illumination device in the image reading apparatus. It is what.

  In particular, in the present invention, when the light emitted from the point light source provided at the longitudinal end of the light guide is irradiated to the image reading position through the light guide, the light is emitted from the point light source to the light guide. It is an object of the present invention to allow light to be easily and appropriately emitted from both sides of an image reading position.

  In order to solve the above-described problems, the image reading illumination device of the present invention is an image reading illumination device that illuminates a reading surface when optically reading an image, and extends in one direction with a light source. A light guide that reflects light from the light source incident from an end in the longitudinal direction and emits light in a first direction and a second direction that intersect the longitudinal direction, and the light guide And a reflecting member provided in the first direction or the second direction with respect to the light body, the light guide is provided along the longitudinal direction, and transmits light from the light source in the first direction. A reflecting portion that reflects in the direction of, and a predetermined interval along the longitudinal direction, and a part of the light reflected by the reflecting portion in the first direction is reflected in the second direction A planar portion, and the reflecting member is provided in the first direction and the second direction. Normal light at the image reading position of the reading surface is sandwiched between light emitted in a given direction and reflected by the reflecting member and light emitted in a direction in which the reflecting member is not provided The image reading position is illuminated from both sides.

  Here, in this illumination device for image reading, the light reflected by the reflecting portion and guided to the flat portion as described above is appropriately reflected by the flat portion so that a sufficient amount of light is emitted. In order to achieve this, it is preferable to incline the planar portion of the light guide to a critical angle or more with respect to the light reflected by the reflecting portion, and to reflect the planar portion of the light guide. Is preferably provided.

  Further, when providing the reflective material so as to be in contact with the flat portion of the light guide as described above, a holding member for holding the light guide so as to be in contact with the flat portion of the light guide is provided. The surface of the holding member in contact with the portion can be made of a reflective material.

  Further, in the case where the light guide is held as described above, this plane is used in order to effectively use the light emitted from the light guide toward the plane holding portion of the holding member in contact with the plane portion of the light guide. It is preferable that an inclined portion is provided in the holding portion, and the light emitted from the light guide toward the flat surface holding portion is reflected by the inclined portion so as to be directed to the reflection member and the image reading position.

  Further, in this image reading illumination device, the light guide is guided to the reflecting member and reflected by the reflecting member as compared with the optical path length of the light directly emitted from the light guide to one side of the image reading position. The optical path length of the light emitted to the opposite side of the image reading position becomes longer, and the intensity of the light irradiated to the opposite side of the image reading position is lowered. For this reason, the width in the longitudinal direction of the planar portion of the light guide and the interval between the planar portions are adjusted so that the amount of light emitted directly from the light guide to one side of the image reading position is reflected by the reflecting member. It is preferable to increase the amount of light emitted to the opposite side of the image reading position and to reduce the difference in intensity of light applied to one side and the opposite side of the image reading position.

  In the image reading apparatus of the present invention, the image reading illumination device as described above is used.

  In the image reading illumination device according to the present invention, light is appropriately irradiated from both sides of the image reading position, which is the reading target position on the reading surface, even when there is a stepped portion or the like on the reading target like a book. As a result, the image information on the reading object such as a document can be appropriately read.

  In addition, among the light reflected toward the reflecting member by the reflecting portion provided along the longitudinal direction of the light guide as described above, the light guided to the planar portion is reflected by this planar portion and guided. Since light emitted from the light body is reflected between the light guides and reflected by the reflecting member and emitted from the light guide body, the width in the longitudinal direction of the flat part and the plane By adjusting the interval between the parts, it is possible to easily and appropriately adjust the intensity of light emitted to one side of the image reading position and the intensity of light emitted to the opposite side of the image reading position, Light can be appropriately irradiated from both sides of the image reading position.

It is the schematic perspective view which showed the arrangement | positioning state of the light source, light guide, holding member, and reflection member which comprise the illuminating device for image reading which concerns on one Embodiment of this invention. FIG. 5 is a schematic explanatory diagram illustrating a state in which light is irradiated from both sides of an image reading position in the image reading illumination device according to the embodiment. In the image reading illumination device according to the above-described embodiment, a partial outline showing a state in which light emitted from a light source into a light guide body is reflected toward a reflection member by a reflection portion provided along the longitudinal direction of the light guide body. It is explanatory drawing. It is a schematic perspective view of the light guide used for the image reading illumination device of the above embodiment. In the image reading illumination device according to the above-described embodiment, the light reflected toward the reflecting member by the reflecting portion provided in the light guide and guided to the flat portion of the light guide is reflected by the flat portion. Light emitted toward one side of the image reading position and light guided to the portion between the flat portions is emitted from the light guide to the reflecting member, and reflected by this reflecting member to the portion on the opposite side of the image reading position. It is the schematic explanatory drawing which showed the state radiate | emitted toward. When providing a plane part in the light guide used for the image reading illumination device of the above embodiment, it is a partial schematic explanatory view showing a state in which the width in the longitudinal direction of the plane part is narrower than the interval between the plane parts. FIG. 5 is a partial schematic perspective view showing a state in which an inclined portion is provided in a light source side portion of a holding member that is in contact with a planar portion of a light guide in the image reading illumination device according to the embodiment. FIG. 5 is a partial cross-sectional explanatory view showing a state where light is reflected and guided to a reflecting member at an inclined portion provided in a portion of a holding member that is in contact with a planar portion of a light guide in the image reading illumination device according to the embodiment. . In the image reading apparatus using the image reading illumination device of the above embodiment, it is a schematic explanatory view showing a state of reading image information at an image reading position on a reading object such as a book.

  Here, an image reading illumination device and an image reading device according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the image reading illumination device and the image reading device according to the present invention are not limited to those shown in the following embodiments, and can be appropriately changed and implemented without departing from the scope of the invention.

  In the image reading illumination device according to this embodiment, as shown in FIG. 1 and FIG. 2, a light guide having a substantially cylindrical shape extending in one direction from an LED light source (light source) 11 mounted on a substrate 11 a. The light guide 12 is held by the holding member 13 at one end portion in the longitudinal direction of the light source 12, and the light guide 12 is sandwiched between the light source side normal line at the image reading position P of the reading surface 1 a of the document reading table 1. A reflecting member 14 is provided at the opposite position.

  Then, the light emitted from the LED light source 11 is emitted in a line shape from one side of the image reading position P to the image reading position P through the light guide 12, and the reflecting member is emitted from the light guide 12. The light emitted toward the image 14 is reflected by the reflecting member 14 and emitted from the opposite side of the image reading position P toward the image reading position P in a line shape. Here, “both sides” of the image reading position P indicate both sides with respect to the normal line at the image reading position P of the reading surface 1a, and “one side” indicates one of the both sides.

  Here, in the light guide body 12, as shown in FIGS. 3 and 4, the light guide body 12 has a zigzag shape along the longitudinal direction of the light guide body 12 in a portion located on the opposite side to the reflection member 14. The reflection part 12a is provided, and the light emitted from the LED light source 11 into the light guide 10 is reflected by the reflection part 12a toward the reflection member 14 (first direction). Here, the zigzag reflecting portion 12a is formed by providing, in the longitudinal direction, recesses having a prism shape that is linear in the lateral direction of the light guide 12 with a pitch of, for example, 1 mm or less. .

  In addition, the light reflected by the reflecting portion 12a is reflected by the portion facing the reflecting member 14 on the side opposite to the reflecting portion 12a, toward the one side of the image reading position P (second direction). A plurality of inclined flat surface portions 12b that are emitted are provided along the longitudinal direction of the light guide 12 with a predetermined interval therebetween.

  Here, each of the first direction and the second direction does not strictly indicate one direction, and depends on the directivity characteristics of the LED light source 11, the reflection characteristics of the reflecting portion 12a and the flat portion 12b, etc. to some extent. This is a broad direction.

  Then, when a plurality of plane portions 12b are provided along the longitudinal direction of the light guide 12 with a required interval on the portion of the light guide 12 facing the reflection member 14 on the side opposite to the reflection portion 12a in this manner, FIG. As shown in FIG. 5, the light reflected by the reflecting portion 12a and guided to the plane portion 12b is reflected by the plane portion 12b and emitted toward one side of the image reading position P, while the plane portion 12b is provided. The light guided to the portion between the flat portion 12b and the flat portion 12b that is not formed is emitted from the light guide 12 toward the reflecting member 14, reflected by the reflecting member 14, and image reading position P. The light is emitted toward the opposite side.

  As described above, both the light reflected by the flat surface portion 12 a and the light reflected by the reflective portion 14 are emitted in a direction intersecting the longitudinal direction of the light guide 12.

  Here, in providing the flat portion 12b in the portion of the light guide 12 facing the reflecting member 14 on the side opposite to the reflecting portion 12a as described above, the light reflected by the reflecting portion 12a enters the flat portion 12b. The angle is set so that the angle is equal to or greater than the critical angle, and the light reflected by the reflecting portion 12a and guided to the plane portion 12b is appropriately reflected, and a sufficient amount of light is emitted toward one side of the image reading position P. It is preferable to do so.

  As described above, according to the configuration in which a plurality of the planar portions 12a are provided along the longitudinal direction of the light guide 12 with a predetermined interval, the intensity of light immediately after exiting from the light guide 12 has strength in the longitudinal direction. However, since the light is emitted from the LED light source 11 with a spread, the light reaching the image reading position P becomes a line-like light in which the intensity unevenness is eliminated.

  In this embodiment, when the light guide 12 is held by the holding member 13, as shown in FIGS. 1 and 2, the holding member 13 is flattened so as to be in contact with the flat portion 12b of the light guide 12. A portion 13a is provided. For this reason, the flat surface portion 13a of the holding member 13 is made of a reflective material, and the light reflected by the reflective portion 12a and guided to the flat surface portion 12b of the light guide 12 is held by the reflective material. It is also possible that the light is reflected by the flat surface portion 13a and emitted toward one side of the image reading position P. Furthermore, in order to prevent light emitted from the LED light source 11 and light reflected in various directions within the light guide 12 from leaking from various positions to the outside, the light guide 12. It is preferable that the surface of the holding member 13 in contact with the reflector is made of a reflective material.

  Further, when light is irradiated from both sides of the image reading position P as described above, the light guide is compared with the optical path length of the light that is reflected by the planar portion 12 b and reaches the image reading position P from the light guide 12. 12, the light path length of the light guided to the reflection member 14 and reflected by the reflection member 14 to reach the image reading position P becomes longer, and the light irradiated from the reflection member 14 side of the image reading position P is longer. The decrease in strength increases. For this reason, in providing a plurality of the planar portions 12b along the longitudinal direction of the light guide 12 with a predetermined interval as described above, the width d1 in the longitudinal direction of each planar portion 12b is set as shown in FIG. The amount of light guided to the reflecting member 14 through the space between the flat surface portion 12b and the flat surface portion 12b is made narrower than the distance d2 between the adjacent flat surface portions 12b and 12b. It is preferable to make the intensity of light emitted from both sides of the image reading position P constant by increasing the amount.

  Further, in order to effectively use the light emitted from the LED light source 11 into the light guide 12 and emitted toward the flat holding portion 13b of the holding member 13 in contact with the flat portion 12b of the light guide 12, FIG. As shown in FIG. 8, an inclined portion 13 c is provided at a portion on the LED light source 11 side in the flat surface holding portion 13 b of the holding member 13 that is in contact with the flat surface portion 12 b of the light guide body 12, and the holding portion that is in contact with the flat surface portion 12 b of the light guide body 12. The light emitted toward the flat surface holding portion 13b of the member 13 can be reflected by the inclined portion 13c and guided to the reflecting member 14.

  In the image reading illumination device described above, the light reflected by the reflecting portion 12a and passing between the flat portion 12b and the flat portion 12b and emitted from the light guide 12 is guided to the reflecting member 14. However, the light reflected by the flat surface portion 12b may be guided to the reflecting member 14, and the light passing between the flat surface portion 12b and the flat surface portion 12b may be emitted toward the image reading position P. However, from the viewpoint of setting the intensity of the light irradiated from both sides to the image reading position P to be constant, the light emitted without being reflected by the flat surface portion 12b is reflected by the reflecting member 14 to read the image. A configuration in which the position P is irradiated is more preferable.

  In the image reading apparatus using such an image reading illumination device, as shown in FIG. 9, the above-described reading object 2 such as a book placed on the document reading table 1 is used as described above. In this way, light is irradiated from both sides of the image reading position P, and the image information reflected on the reading object 2 at the image reading position P is passed through the first mirror 3a, the second mirror 3b, and the third mirror 3c to form the imaging lens 4. Then, the image forming lens 4 forms an image on the image pickup device 5 to read the image information at the image reading position P.

  If it does in this way, light will be appropriately irradiated with respect to the reading target object 2 from the both sides of the image reading position P by said illumination device for image reading, and it will float like the reading target object 2 like a book. Even if there is a portion, it is possible to read appropriate image information without a shadow by appropriately irradiating light.

DESCRIPTION OF SYMBOLS 1 Original reading stand 1a Reading surface 2 Reading object 3a 1st mirror 3b 2nd mirror 3c 3rd mirror 4 Imaging lens 5 Image pick-up element 11 LED light source (light source)
12 Light Guide 12a Reflector 12b Plane Part 13 Holding Member 13a Plane Part 13b Plane Holder 13c Inclined Part 14 Reflecting Member d1 Longitudinal Width of Plane Part of Light Guide d2 Space Between Plane Part

Claims (7)

An image reading illumination device for illuminating a reading surface when optically reading an image,
A light source;
A light guide that has a shape extending in one direction, reflects light from the light source incident from the end in the longitudinal direction, and emits light in the first direction and the second direction intersecting the longitudinal direction When,
A reflective member provided in the first direction or the second direction with respect to the light guide,
The light guide is provided along the longitudinal direction, and is provided with a reflecting portion that reflects light from the light source in the first direction, and has a predetermined interval along the longitudinal direction, and the reflection A plane portion that reflects a part of the light reflected in the first direction by the portion in the second direction;
Of the first direction and the second direction, light emitted in the direction in which the reflecting member is provided and reflected by the reflecting member, and in the direction in which the reflecting member is not provided An image reading illumination device, wherein the image reading position is illuminated from both sides of the normal line at the image reading position of the reading surface with the light.   The image reading illumination device according to claim 1, wherein the planar portion is provided in a direction in which an incident angle of the light reflected by the reflecting portion to the planar portion is equal to or greater than a critical angle. Lighting equipment.   The image reading illumination device according to claim 1, wherein a reflecting material is provided so as to be in contact with the planar portion.   The illumination device for image reading according to claim 3, wherein a holding member that holds the light guide is provided so as to be in contact with the flat portion, and a surface of the holding member that is in contact with the flat portion is configured by a reflective material. A characteristic image reading apparatus.   5. The illumination device for reading an image according to claim 4, wherein an inclined portion that reflects light that has passed through the light guide and is incident on a portion of the holding member that is not in contact with the light guide in the first direction. An image reading apparatus provided on a holding member. 6. The illumination device for reading an image according to claim 1, wherein the reflecting member is provided in the first direction, and the width of the planar portion in the longitudinal direction is set to the plane. An illumination device for reading an image, characterized by being narrower than the interval between the parts.   An image reading device comprising the image reading illumination device according to claim 1.

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