JP2012114777A - Original illumination device, original reader and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original illumination device suppressing occurrence of color irregularity due to an illumination region difference between blue light and yellow light, which are emitted from a white LED light source in a light irradiation region, and to provide an original reader equipped with the original illumination device, and an image forming device.SOLUTION: The original illumination device irradiates an original reading face with light. The original illumination device includes: a light emitting portion consisting of a plurality of white LED light sources 41 which are linearly arranged in a main scanning direction of the light irradiation region on the original reading face; and a diffusion member 40 disposed between the light emitting portion and the original reading face. The diffusion member 40 is an anisotropic diffusion member where a diffusion degree in the second direction orthogonal with the first direction is larger than that in the first direction on the diffusion face. The diffusion member 40 is arranged so that the second direction inclines to an arranging direction of the plurality of white LED light sources 41 in the original illumination device. The original reader equipped with the original illumination device, and the image forming device are also installed.

Description

  The present invention relates to a document illumination device that illuminates a document in a document reading device used for a digital copying machine, an image scanner, and the like, a document reading device including the document illumination device, and an image forming apparatus.

  2. Description of the Related Art Conventionally, a document reading device such as a scanner has a light source that is arranged on a contact glass and emits light toward a document reading surface of a document to be read, and is read after being reflected by the document reading surface. There is known a technique in which reading light traveling along an axis is imaged on an image reading unit such as a CCD via a lens to read a document image.

As a light source of the document illumination device provided in such a document reading device, for example, a linear light source such as a fluorescent lamp or a xenon lamp, or a point light source such as a light emitting diode (hereinafter referred to as “LED”) is used. Side by side is used.
LEDs generally have advantages such as long life, high efficiency, high G resistance, and monochromatic light emission. By using a point light source such as an LED as a light source, the size and consumption of an image reading apparatus can be reduced. Electric power can be reduced.

  An example of a white LED element used as a light source of a document illumination device is shown in FIG. As shown in FIG. 2, the white LED light source 41 includes a blue light emitting chip 52 and a phosphor 53 for converting blue light emitted from the blue light emitting chip into yellow light. A part of the blue light emitted from the blue light emitting chip 52 is converted into yellow light, the remaining blue light component is transmitted as blue light, and these two colors of blue and yellow light are mixed together, so that White light is generated.

  Since the light emission positions are different from each other, the illumination positions and the illuminances of the blue light and the yellow light in the light emitted from the white LED light source 41 have a relationship as shown in FIG. That is, the illuminance ratio between yellow light and blue light is constant in the central portion of the illumination position, and thus white. However, in the peripheral portion, the blue illumination ratio decreases, resulting in yellowish white light.

  For this reason, when the white LED light sources 41 are arranged in a line to constitute the document illumination device, even in the arrangement direction (main scanning direction), the illumination light may be uneven in color due to the overlapping of light. In addition, color unevenness also occurs in the direction (sub-scanning direction) perpendicular to the arrangement direction of the white LED light sources 41, so that there is a problem that the read color changes depending on the illumination color.

  For example, an illumination device provided with a special optical lens in combination with a white LED light source (for example, refer to Patent Document 1) or a multi-reflector to make the light uniform in the multi-reflection device. An illuminating device that emits light (for example, see Patent Document 2) has been proposed.

  On the other hand, an anisotropic diffuser plate (elliptical diffuser plate) having different characteristics of the diffusivity in two orthogonal directions on the diffusion surface is disposed between the light emitting unit and the original reading surface, and the illumination light is scanned in the main scanning direction. A method for suppressing the unevenness in the amount of light has also been proposed (see, for example, Patent Document 3).

  However, the document illumination devices of Patent Documents 1 and 2 need to include a large number of special optical lenses, multiple reflection devices (rod lenses), etc., increase the number of parts, and require mounting means such as rod lenses. For this reason, the cost is increased and a mounting space is required, which is disadvantageous for downsizing of the apparatus.

  In the document illumination device of Patent Document 3, it is said that the uneven light amount in the main scanning direction of illumination light can be suppressed by setting the direction of high diffusion rate of the anisotropic diffusion plate as the main scanning direction. There is a problem that the occurrence has not been resolved.

  Therefore, an object of the present invention is to provide an original illuminating device in which the occurrence of color unevenness due to a difference in illumination area between blue light and yellow light emitted from a white LED light source in the light irradiation region is suppressed, and the original illuminating device. An original reading apparatus and an image forming apparatus are provided.

In order to solve the above-described problems, a document illumination device, a document reading device, and an image forming apparatus according to the present invention are as follows.
[1] A document illumination device that irradiates a document reading surface of a document reading device with light,
A light emitting unit comprising a plurality of white LED light sources arranged linearly in the main scanning direction of the light irradiation region of the original reading surface;
A diffusion member provided between the light emitting unit and the document reading surface;
The diffusing member is an anisotropic diffusing member in which the diffusivity in the second direction orthogonal to the first direction is larger than the diffusivity in the first direction on the diffusing surface,
In the document illumination device, the diffusing member is disposed so that the second direction is inclined with respect to the arrangement direction of the plurality of white LED light sources.
[2] A condensing member that condenses light emitted from the white LED light source in a sub-scanning direction of the light irradiation region between the light emitting unit and the diffusion member, and the diffusion member The document illumination device according to [1], wherein the light from the condenser is diffused.
[3] The document illuminating device according to [2], wherein the condenser is a lens.
[4] The document illumination device according to [2], wherein the light collector is a concave mirror or a polygonal concave mirror.
[5] A light guide that guides light emitted from the white LED light source is provided between the light emitting unit and the diffusion member, and the diffusion member diffuses light from the light guide. The document illuminating device according to [1], characterized in that:
[6] Any one of [1] to [5], wherein the diffusing member is arranged so as to be perpendicular to an optical axis connecting the plurality of white LED light sources and the document reading surface. The document illumination device according to claim 1.
[7] The two light source sections and the light collector are provided on one side and a reflecting member is provided on the other side so as to be substantially symmetrical with respect to the central axis in the sub-scanning direction of the light irradiation region. The diffusion member is provided between the document reading surface and between the reflection member and the document reading surface, respectively.
The original according to [3], wherein the first light source unit is arranged to irradiate light on the original reading surface, and the second light source unit is arranged to irradiate light to the reflecting member. It is a lighting device.
[8] The light source section and the light collecting body are provided on one side and a reflecting member is provided on the other side so as to be substantially symmetric with respect to the central axis in the sub-scanning direction of the light irradiation region. The diffusion member is provided between the document reading surface and between the reflection member and the document reading surface,
The light source unit irradiates light to the light collector and the reflection member, respectively, and the light reflected by the light collector and the reflection member is irradiated to the document reading surface. The document illumination device described in the above.
[9] The light source section and the light guide body are provided on one side and a reflecting member is provided on the other side so as to be substantially symmetrical with respect to the central axis in the sub-scanning direction of the light irradiation region. The diffusion member is provided between the document reading surface and between the reflection member and the document reading surface,
The document illumination device according to [5], wherein the light source unit irradiates light to the light guide, and light from the light guide irradiates the document reading surface and the reflection member. is there.
[10] A document reading apparatus comprising the document illumination device according to any one of [1] to [9], wherein the document illumination device reads information on a document illuminated by the document illumination device.
[11] An image forming apparatus comprising the document reading device according to [10].

  According to the present invention, the light emitting unit composed of a plurality of white LED light sources arranged linearly in the main scanning direction of the light irradiation region of the original reading surface, and the diffusivity in the first direction on the diffusion surface, An anisotropic diffusing member having a large diffusivity in a second direction orthogonal to the first direction is provided, and the diffusing member is inclined in the second direction with respect to the arrangement direction of the plurality of white LED light sources. In the light irradiation area, the original illumination apparatus in which the occurrence of color unevenness due to the illumination area difference between the blue light and the yellow light emitted from the white LED light source is suppressed in the light irradiation area, and the original illumination It is possible to provide an original reading apparatus including the apparatus and an image forming apparatus.

It is the schematic which shows one Embodiment of the original document illuminating device of this invention. It is a schematic diagram of the cross section which shows the structure of white LED. It is the figure which showed an example of the illumination intensity distribution of white LED. 1 is a schematic front view showing an internal structure of a full-color copying machine which is an embodiment of an image forming apparatus of the present invention. It is a figure which shows the characteristic of the anisotropic diffusion plate which is a diffusion member of the original illuminating device of this invention. It is a figure explaining mounting of the anisotropic diffusion plate in the conventional original illuminating device. It is a figure explaining mounting of the anisotropic diffusion plate in the original illuminating device of this invention. It is a schematic diagram which shows the state in which the light from white LED was irradiated through the anisotropic diffusion plate. FIG. 6 is a schematic diagram showing a state in which light from a plurality of white LEDs arranged in the main scanning direction is irradiated through an anisotropic diffusion plate in a conventional document illumination device. FIG. 6 is a schematic diagram illustrating an example of a state in which light from a plurality of white LEDs arranged in the main scanning direction is irradiated through an anisotropic diffusion plate in the document illumination device of the present invention. It is a schematic diagram which shows the conventional example which provided the rod lens as a condensing body and has arrange | positioned the 2nd direction of the anisotropic diffusion plate in the main scanning direction. It is the figure which showed the illumination intensity distribution of the blue light of the light irradiation area | region in the document illuminating device of FIG. 11, and yellow light. It is a schematic diagram which shows the state of the light irradiation area | region in the original illuminating device of FIG. It is the schematic which shows other embodiment (2nd Embodiment) of the original document illuminating device of this invention. It is the figure which showed the illumination intensity distribution of the blue light of the light irradiation area | region in the original illuminating device of FIG. 14, and yellow light. It is a schematic diagram which shows the state of the light irradiation area | region in the original illuminating device of FIG. It is the schematic which shows other embodiment (3rd Embodiment) of the original document illuminating device of this invention. It is the schematic which shows other embodiment (4th Embodiment) of the original document illuminating device of this invention. It is the schematic which shows other embodiment (5th Embodiment) of the original document illuminating device of this invention. It is the schematic which shows other embodiment (6th Embodiment) of the original document illuminating device of this invention. It is the schematic which shows other embodiment (7th Embodiment) of the original document illuminating device of this invention.

  Hereinafter, a document illumination device, a document reading device, and an image forming apparatus according to the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the embodiments of the examples shown below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art. Any aspect is included in the scope of the present invention as long as the operations and effects of the present invention are exhibited.

[First Embodiment]
(Original lighting device)
FIG. 1 is a schematic view showing an example of a document illumination device of the present invention.
As shown in FIG. 1, the document illumination device 18 of the present invention is linear in the main scanning direction of the light irradiation area (hereinafter also referred to as “illumination area”) of the reading surface 12 a of the document placed on the contact glass 12. A light-emitting unit composed of a plurality of white LED light sources 41 arranged in a shape, and a diffusion member (hereinafter also referred to as “anisotropic diffusion plate”) 40 provided between the light-emitting unit and the document reading surface 12a. The diffusing member 40 is an anisotropic diffusing member having a diffusivity in a second direction orthogonal to the first direction larger than a diffusivity in the first direction on the diffusing surface. The diffusion member 40 is disposed so that the second direction is inclined with respect to the arrangement direction of the light sources 41. Note that the first direction and the second direction of the diffusing member 40 correspond to a short axis and a long axis in elliptical diffusion. That is, the direction in which the diffusion angle is narrow (short axis) when the illuminance distribution becomes elliptical due to the diffusing action of the diffusing member 40 is the first direction, and the wide direction (major axis) is the second direction.

  In the document illumination device 18, a plurality of white LED light sources 41 are arranged (in the direction perpendicular to the paper surface) and fixed on the substrate 42. The substrate 42 is fixed to the holder 43 by bonding or screwing (not shown). The light emitted from the white LED light source 41 passes through the diffusing member 40 fixed to the holder 43 by the screw 45 and the washer 44, is diffused, and is the original reading surface 12 a on the surface of the contact glass 12 surrounded by the illumination region end 50. Illuminate.

FIG. 5 illustrates a state in which the light 48 is irradiated perpendicularly to the diffusion member 40 that is an anisotropic diffusion plate. The first direction on the diffusion surface is indicated by an arrow 46, and is orthogonal to the first direction. The second direction is indicated by an arrow 47. Since the diffusing member 40 has a diffusivity in the second direction perpendicular to the first direction 46 larger than that in the first direction 46 on the diffusing surface, the incident light 48 is elliptical in the light irradiation region. The illumination area 49 has a shape.
In the document illumination device of the present invention, as shown in FIG. 5, the diffusing member 40 may be arranged so as to be perpendicular to the optical axis connecting the plurality of white LED light sources 41 and the document reading surface 12a. preferable.

  In the conventional document illuminating apparatus, the diffusing member 40, which is an anisotropic diffusing plate, has a second direction 47 having a high diffusivity arranged in the arrangement direction (main scanning direction) of the white LED light sources 41, as shown in FIG. Installed. On the other hand, in the present invention, as shown in FIG. 7, the diffusing member 40 is arranged so that the second direction 47 having a high diffusivity is inclined at an angle θ with respect to the main scanning direction. By arranging in this way, it is possible to suppress the occurrence of color unevenness at the end of the light irradiation region in the main scanning direction.

FIG. 8 is a schematic view showing an illumination area 49 irradiated with light from the white LED light source 41 through the diffusing member 40. Due to the difference in the illumination ratio between blue light and yellow light as shown in FIG. 3, a non-uniform color region 60 having a yellow color is generated at the end portion in the direction of high diffusivity. FIG. 9 shows an example of illumination by a conventional document illumination device, in which a plurality of illumination areas as shown in FIG. 8 are arranged in the main scanning direction, and the uneven color area 60 is distributed in the main scanning direction of the illumination range 61. ing. In this case, the illumination is uneven in the main scanning direction, and accurate image reading cannot be performed.
On the other hand, in the original illuminating device of the present invention, since the direction in which the diffusivity, which is the second direction of the diffusing member 40, is large is inclined with respect to the arrangement direction of the white LED light sources 41, it is shown in FIG. Thus, it can illuminate so that the uneven color area | region 60 may become out of the illumination range 61, and generation | occurrence | production of the uneven color of the illumination range 61 can be suppressed.

The suppression of color unevenness will be described with specific numerical values. The divergence angle of the white LED light source 41 is 20 degrees at half-width, the diffusivity of the diffusing member 40, which is an anisotropic diffusion plate, is 60 degrees and 1 degree at half-width, and the distance between the white LED light source 41 and the document reading surface 12a. Assuming 24 mm, the illumination area is 63.2 degrees (= (20 ² +60 ² ) ^0.5 ) and 20 degrees (= (20 ² +1 ² ) ^0.5 ), and the illumination range is 95 mm (= 2 × 24 × (tan 63.2 degrees)) and 17.5 mm (= 2 × 24 × (tan 20 degrees)). The direction (long direction) with a large diffusivity shown in FIG. 8 is 95 mm, and the direction with a small diffusivity (short direction) is 17.5 mm. Therefore, when the illumination areas are arranged as shown in FIG. 9, the end of the illumination area 95 mm by the light emitted from one white LED light source 41 becomes an uneven color area.

On the other hand, if the uneven color region is 16 mm in the end in the direction of high diffusivity and the illumination range 61 is 5 mm, the original illumination device of the present invention has 4.4 degrees (((95-16-16) ² + 17.5 ² ) ^0.5 = 65.4, 4.4 = tan −1 (5 / 65.4)) If tilted, the uneven color region 60 is outside the illumination range 61 as shown in FIG. It is possible to illuminate so that color unevenness in the illumination range 61 can be reduced.
As described above, in the conventional document illumination device, color unevenness occurs because the ratio of blue light to yellow light is different in the main scanning direction. However, according to the document illumination device of the present invention, blue light and yellow light are generated. The illumination with no color unevenness can be realized with a constant ratio.

(Original reading device, image forming device)
FIG. 4 is a schematic front view showing the internal structure of a full-color copying machine which is an embodiment of the image forming apparatus of the present invention.
An image forming unit 3 for forming a color image is provided at the center of the main body 2 of the image forming apparatus 1. The image forming unit 3 includes four drum-shaped photosensitive members 4 that are spaced apart at equal intervals and arranged in parallel in the horizontal direction, a charging roller 5 that uniformly charges the outer peripheral surface of the photosensitive member 4, and a charging roller 5 An exposure device 6 that forms an electrostatic latent image by exposing the outer peripheral surface of each of the photosensitive members 4 charged in accordance with image data according to the image data, and supplying the toner to the electrostatic latent image to convert the electrostatic latent image into a toner image. A developing device 7 that visualizes the toner image, an intermediate transfer belt 8 to which the toner image on the photoconductor 4 is sequentially transferred, and a cleaning that removes toner remaining on the photoconductor 4 after the transfer of the toner image onto the intermediate transfer belt 8. The apparatus 9 includes a transfer roller 10 that transfers the toner image transferred onto the intermediate transfer belt 8 to the recording medium S, and the like.

  Note that toner images of different colors (Y: yellow, M: magenta, C: cyan, K: black) are formed on the four photoconductors 4, and the toner images of these colors are formed on the intermediate transfer belt 8. By being transferred, a color toner image is formed on the intermediate transfer belt 8, and the color toner image is transferred to the recording medium S.

  An upper part of the apparatus main body 2 has an ADF 11 that automatically feeds a document that is an object to be illuminated by the document illumination device of the present invention, a contact glass 12 on which the document is placed, and a document or contact glass that is automatically fed by the ADF 11. An image reading device 13 of the present invention that reads a document placed on the image reading apparatus 12 is disposed.

  The document reading device 13 of the present invention includes first and second traveling bodies 14 and 15 that can travel at a speed of 2: 1 parallel to the contact glass 12, a lens 16, a CCD 17 that is an image reading unit, and the like. . The first traveling body 14 includes a document illumination device 18 of the present invention for illuminating a document reading surface of a document placed on the contact glass 12 or a document conveyed by the ADF 11, and is reflected by the document reading surface. The first mirror 19 that reflects the reading light traveling along the reading optical axis is mounted. The second traveling body 15 is equipped with a second mirror 20 and a third mirror 21 that further reflect the light reflected by the first mirror 19. A lens 16 and a CCD 17 are arranged in front of the traveling direction of the reading light sequentially reflected by the first to third mirrors 19, 20, and 21.

  A plurality of, for example, four-stage paper cassettes 24 for storing the recording medium S are provided at the lower part of the apparatus main body 2. The recording media S stored in these paper cassettes 24 are separated and fed one by one by a pickup roller 25 and a feed roller 26, and the separated and fed recording media S are conveyed by a sheet provided in the apparatus main body 2. It is conveyed along the path 27. On the paper conveyance path 27, a registration roller 28, a transfer roller 10, a fixing device 29, a paper discharge roller 30, and the like are disposed.

  In such a configuration, laser light corresponding to the image data of each color (yellow Y, magenta M, cyan C, black K) is emitted from the semiconductor laser of the exposure device 6 according to the reading result by the document reading device 13 of the present invention. An electrostatic latent image is formed by exposing the outer peripheral surface of each photoconductor 4 that is emitted and the laser beam is uniformly charged by the charging roller 5. Each color toner is supplied from each developing device 7 to the electrostatic latent image, whereby each color toner image is formed. The toner image on each photoconductor 4 is sequentially transferred onto an intermediate transfer belt 8 that moves in synchronization with the photoconductor 4, and a color toner image is formed on the intermediate transfer belt 8.

  On the other hand, with the start of the image forming operation in the image forming unit 3, the recording medium S is started to be separated and fed from the sheet cassette 24, and the separated recording sheet S is conveyed on the sheet conveyance path 27. Is transferred to a transfer position between the intermediate transfer belt 8 and the transfer roller 10 by a registration roller 28 that is intermittently rotated.

  Next, the registration roller 28 is driven to rotate, and the recording medium S is fed between the intermediate transfer belt 8 and the transfer roller 10, whereby the color toner image on the intermediate transfer belt 8 is transferred onto the recording medium S. The color toner image transferred onto the recording medium S is fixed to the recording medium S in the process in which the recording medium S passes through the fixing device 29, and the recording medium S on which the color toner image is fixed is discharged by the discharge roller 30. The paper is discharged onto the tray 31.

[Second Embodiment]
FIG. 14 is a schematic view showing a second embodiment of the document illumination device of the present invention.
As shown in FIG. 14, the document illumination device 18 of the present embodiment includes a rod lens 62 as a condenser, and the diffusing member 40 is in the second direction with respect to the arrangement direction of the plurality of white LED light sources 41. Are arranged to be inclined.

  Here, although the rod lens 62 is provided as a condensing body, the conventional example which has arrange | positioned the said 2nd direction of the diffusing member 40 as an arrangement direction of the several white LED light source 41 is shown in FIG. As shown in FIG. 11, the rod lens 62 can collect the irradiation light in the vicinity of the center 51 of the illumination area, and can increase the light use efficiency. However, an uneven color region occurs near the center 51 of the illumination region. FIG. 12 is a diagram showing the illuminance distribution of blue light and yellow light in the illumination area in the embodiment of FIG. 11, and it can be seen that blue light rays are gathered at the center. FIG. 13 is a schematic diagram showing the illumination range 61 in the aspect of FIG. 11, and shows that a blue color uneven region 63 is generated at the center in the sub-scanning direction 61. As described above, this is because, as shown in FIG. 2, in the white LED light source 41, the positions of the blue light emitting unit 52 and the yellow light emitting unit 53 are different. This is because the light is collected near the center 51, but the light from the yellow light emitting portion 53 spreads.

  On the other hand, in the second embodiment of the present invention shown in FIG. 14, the illuminance distribution of the blue light and the yellow light in the illumination area is flat in the central portion as shown in FIG. Further, as shown in FIG. 16, the illumination range 61 in the aspect of FIG. 14 has a flat illuminance distribution in the uneven color region 63 where the blue light was strong, and the illumination range 61 becomes a region 64 with no uneven color, Blue color unevenness is eliminated.

The suppression of the occurrence of uneven color in the present embodiment will be described with specific numerical values.
The blue light beam travels straight through the rod lens 62 that is a condenser, the distance between the diffusing member 40 and the illumination region center 51 is 20 mm, and the diffusivity of the diffusing member 40 that is an anisotropic diffusing plate is 20 degrees at half maximum half-width. Once. Under this condition, the blue light beam is 14.6 mm (= 2 × 20 × (tan 20 degrees)) and 0.7 mm (= 2 × 20 × (tan 1 degree)). Therefore, the sub-direction expansion range of blue light when the inclination angle θ shown in FIG. 7 is 0 is 0.7 mm. The expansion range W in the sub-scanning direction varies depending on the value of the inclination angle θ, and has a relationship represented by the following formula 1. To set W = 5 mm, θ = 17 degrees may be set.
W = 14.6 × sin θ + 0.7 (Expression 1)

[Third Embodiment]
FIG. 17 is a schematic view showing a third embodiment of the document illumination device of the present invention.
As shown in FIG. 17, two light source sections each including a plurality of white LED light sources 41 and 41 a and a light collector 62 so as to be substantially symmetrical with respect to the central axis 51 in the sub-scanning direction of the light irradiation region. A reflection member 65 is provided on the other side, a diffusion member 40 is provided between the light collector 62 and the document reading surface 12a, and a diffusion member 40a is provided between the reflection member 65 and the document reading surface 12a. The unit irradiates light to the original reading surface 12a, and the second light source unit is disposed so as to irradiate the reflection member 65 with light.

  The second light source unit includes a substrate 42a for fixing the white LED light source 41a constituting the light source unit, and the emitted light passes through a rod lens 62 that is a condenser, and is irradiated onto the mirror 65. The mirror 65 is held by a mirror holder 66, and a diffusion member 40 a is fixed to the mirror holder 66 by screws 45 and washers 44. The light reflected by the mirror 65 passes through the diffusion member 40a and travels toward the illumination area center 51. Similar to the diffusing member 40, the diffusing member 40a is arranged such that the second direction having a high diffusivity is inclined with respect to the main scanning direction, thereby suppressing the occurrence of color unevenness due to the concentration of blue light. Lighting with no color unevenness is possible.

  As described above, by adopting a configuration in which light is irradiated from the light source portion and the reflecting member arranged substantially symmetrically, an effect of eliminating a shadow generated when a cut and pasted document or an uneven document is read can be obtained. Moreover, since two light sources can be condensed by one light collector, it is advantageous for miniaturization and cost reduction.

[Fourth Embodiment]
FIG. 18 is a schematic view showing a fourth embodiment of the document illumination device of the present invention.
As shown in FIG. 18, the document illumination device 18 of the present embodiment includes a concave mirror or a concave mirror in which concave mirrors are arranged in a concave shape as the condenser 67, and the diffusion member 40 includes a plurality of white LED light sources. The second direction is inclined with respect to the arrangement direction of 41.
In the case of the present embodiment, by appropriately adjusting the surface shape of the concave mirror, the light can be efficiently condensed near the center 51 of the illumination area.
In addition, when the light is condensed, an uneven color region with strong blue light as described with reference to FIGS. 11 to 13 may occur. However, as in the second embodiment, the diffusion member 40 has a high diffusivity. By arranging the direction 2 to be inclined with respect to the main scanning direction, the occurrence of color unevenness can be eliminated.

[Fifth Embodiment]
FIG. 19 is a schematic view showing a fifth embodiment of the document illumination device of the present invention.
As shown in FIG. 19, the document illumination device 18 of the present embodiment includes a light source unit including a plurality of white LED light sources 41 on one side so as to be substantially symmetric with respect to the central axis in the sub-scanning direction of the light irradiation region. The condensing body 67 is provided with a reflecting member 65 on the other side, and the diffusing member 40 is provided between the condensing body 67 and the document reading surface 12a and between the reflecting member 65 and the document surface reading surface 12a. The light source unit irradiates light to the light collector 67 and the reflection member 65, respectively, and the light reflected by the light collector 67 and the reflection member 65 is irradiated to the document reading surface 12a.

  The arrangement is such that a part of the light emitted from the white LED light source 41 shown on the left side of FIG. 19 is applied to the reflecting member 65 which is a reflecting mirror, and the light reflected by the reflecting member 65 is a diffusing member. The light passes through 40a and is irradiated to the center 51 of the illumination area. Similarly to the reflecting member 40, the diffusing member 40a is also arranged so that the second direction is inclined with respect to the arrangement direction of the plurality of white LED light sources 41, thereby preventing the occurrence of color unevenness and in the illumination area. This makes it possible to illuminate evenly.

  As described above, by adopting a configuration in which light is irradiated from the light source portion and the reflecting member arranged substantially symmetrically, an effect of eliminating a shadow generated when a cut and pasted document or an uneven document is read can be obtained. However, when the ratio of the light reaching the reflecting member 65 is small, the influence on the color unevenness is also small, and therefore, the configuration in which the diffusing member 40a is not provided may be employed. Although FIG. 19 shows an example in which the reflecting member 65 is a plane mirror, illumination efficiency can be improved by using a concave mirror.

[Sixth Embodiment]
FIG. 20 is a schematic view showing a sixth embodiment of the document illumination device of the present invention.
As shown in FIG. 20, the document illumination device 18 of the present embodiment includes a light guide as the light collector 68, and the diffusing member 40 is arranged in the second direction with respect to the arrangement direction of the plurality of white LED light sources 41. It is arranged so that the direction is inclined. By providing the light guide body 68 having a shape as shown in FIG. 20, a light condensing action is generated, and the light can be efficiently collected at the center 51 of the illumination area.
As described above, when the light is condensed, an uneven color region of strong blue light may occur. However, as in the second embodiment, the diffusing member 40 has a second diffusivity in the second direction with respect to the main scanning direction. Occurrence of color unevenness can be eliminated by disposing it so as to be inclined.
The diffusing member 40 can be fixed by being adhered to the light guide 68.

[Seventh Embodiment]
FIG. 21 is a schematic view showing a seventh embodiment of the document illumination device of the present invention.
As shown in FIG. 21, the document illumination device 18 according to the present embodiment includes a light source unit including a plurality of white LED light sources 41 on one side so as to be substantially symmetrical with respect to the central axis in the sub-scanning direction of the light irradiation region. The light guide 68 is provided with a reflection member 65 on the other side, and diffusion members 40 and 40a are provided between the light guide 68 and the document reading surface 12a and between the reflection member 65 and the document surface reading surface 12a, respectively. The light source unit irradiates the light guide 68 with light, and the light from the light guide 68 irradiates the document reading surface 12 a and the reflection member 65.

In the present embodiment, the light guide 68 shown on the left side of FIG. 21 is a type that does not have a light collecting function, and the diffusing member 40 is fixed by a part of the holder 43 and travels from the light guide 68 to the illumination region. Only light is arranged to pass through the diffusing member 40. The light guide 68 is arranged so that the peak of the emitted light from the white LED light source 41 is slightly on the right side in FIG. 21 and a part of the emitted light is reflected by the reflecting member 65 held by the mirror holder 66. Has been.
The light reflected by the reflecting member 65 passes through the diffusing member 40a and travels toward the illumination area of the document reading surface 12a. The diffusing member 40a is held at a position where it does not block the incident light beam on the reflecting member 65 but passes the reflected light from the reflecting member 65. Specifically, it may be bonded and fixed to a part of the mirror holder 66.

As described above, by adopting a configuration in which light is irradiated from the light source portion and the reflecting member arranged substantially symmetrically, an effect of eliminating a shadow generated when a cut and pasted document or an uneven document is read can be obtained.
Although FIG. 21 shows an example in which the reflecting member 65 is a plane mirror, illumination efficiency can be improved by using a concave mirror.

  In the first to seventh embodiments, the document illuminating device of the present invention is arranged so that the light beam incident on the diffusing member 40 enters the diffusing member 40 perpendicularly. When the light does not enter perpendicularly, the light beam is bent, and thus it is not suitable as a method of using the document illumination device of the present invention.

  In the first, second, fourth, and sixth embodiments, illumination is performed only from one side with respect to the central axis in the sub-scanning direction of the light irradiation region. By providing a unit composed of a light source part and a diffusing member so as to be symmetric with respect to the central axis in the sub-scanning direction of the light irradiation region from the other side, both-side illumination is obtained, and a larger amount of illumination is required This is an effective configuration. Even in the case of such a configuration, the effect of suppressing the occurrence of color unevenness due to the illumination area difference between the blue light and the yellow light emitted from the white LED light source in the light irradiation area can be similarly obtained.

S Recording medium Y Yellow M Magenta C Cyan K Black 1 Image forming device (copier)
DESCRIPTION OF SYMBOLS 2 Apparatus main body 3 Image formation part 4 Photoconductor 5 Charging roller 6 Exposure apparatus 7 Developing apparatus 8 Intermediate transfer belt 9 Cleaning apparatus 10 Transfer roller 11 ADF
12 Contact Glass 12a Document Reading Surface 13 Document Reading Device 14 First Traveling Body 15 Second Traveling Body 16 Lens 17 CCD
18 Document illumination device 19 First mirror 20 Second mirror 21 Third mirror 24 Paper cassette 25 Pickup roller 26 Feed roller 27 Paper transport path 28 Registration roller 29 Fixing device 30 Paper discharge roller 31 Paper output tray 40, 40a Diffusing member (different Isotropic diffuser)
41, 41a White LED light source 42, 42a Substrate 43 Holder 44 Washer 45 Screw 62 Condenser (rod lens)
65 Reflective member 66 Mirror holder 67 Condenser (concave mirror)
68 Light guide

JP 2007-132178 A JP 2005-339853 A JP 2009-246462 A

Claims (11)

A document illumination device for irradiating a document reading surface of a document reading device with light,
A light emitting unit comprising a plurality of white LED light sources arranged linearly in the main scanning direction of the light irradiation region of the original reading surface;
A diffusion member provided between the light emitting unit and the document reading surface;
The diffusing member is an anisotropic diffusing member in which the diffusivity in the second direction orthogonal to the first direction is larger than the diffusivity in the first direction on the diffusing surface,
The original illuminating apparatus, wherein the diffusing member is arranged so that the second direction is inclined with respect to an arrangement direction of the plurality of white LED light sources.   Between the light emitting part and the diffusing member, there is a condensing body for condensing the light emitted from the white LED light source in the sub-scanning direction of the light irradiation region, and the diffusing member is the condensing body The original illumination device according to claim 1, wherein light from the original is diffused.   The document illumination device according to claim 2, wherein the condenser is a lens.   The document illuminating apparatus according to claim 2, wherein the condenser is a concave mirror or a polygonal concave mirror.   A light guide that guides light emitted from the white LED light source is provided between the light emitting unit and the diffusion member, and the diffusion member diffuses light from the light guide. The document illumination device according to claim 1.   6. The document illumination according to claim 1, wherein the diffusing member is disposed so as to be perpendicular to an optical axis connecting the plurality of white LED light sources and the document reading surface. apparatus. The two light source sections and the light collecting body are provided on one side and the reflecting member is provided on the other side so that the light irradiation area is substantially symmetric with respect to the central axis in the sub-scanning direction of the light irradiation region. Each of the diffusion members, and between the reflection member and the document reading surface,
4. The document illumination according to claim 3, wherein the first light source unit is arranged to irradiate the document reading surface with light, and the second light source unit is arranged to irradiate the reflection member with light. apparatus. The light source section and the light collecting body are provided on one side and a reflecting member is provided on the other side so as to be substantially symmetrical with respect to the central axis in the sub-scanning direction of the light irradiation region, and the light collecting body and the original reading surface. And the diffusion member between the reflection member and the document reading surface,
5. The light source unit irradiates light to the light collector and the reflection member, respectively, and the light reflected by the light collector and the reflection member is irradiated to the document reading surface. The document illumination device described in 1. The light source section and the light guide body are provided on one side and the reflection member is provided on the other side so that the light irradiation area is substantially symmetric with respect to the central axis in the sub-scanning direction of the light irradiation area. And the diffusion member between the reflection member and the document reading surface,
6. The document illumination device according to claim 5, wherein the light source unit irradiates the light guide with light, and the light from the light guide irradiates the document reading surface and the reflection member.   An original reading apparatus comprising the original illumination device according to claim 1, wherein the original reading apparatus reads information on an original illuminated by the original illumination device.   An image forming apparatus comprising the document reading device according to claim 10.

Images