JP2012100141A - Original document illuminating device, original document reading device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original document illuminating device, an original document reading device, and an image forming apparatus, capable of reducing effectively color unevenness in an illumination region in a scanning direction and obtaining a wider white illumination region.SOLUTION: An original document reading device includes an original document illumination unit having a light emission section comprising a plurality of LED light sources 1 disposed along a main scanning direction of a light irradiation region and a diffusion member 2 arranged between the light emission section and an original document reading surface 3, and the diffusion member 2 is an aeolotropic diffusion member having larger diffusivity in a second direction perpendicular to a first direction than the diffusivity in the first direction in a diffusion surface, and the light emission section and the diffusion member 2 are arranged so that a normal vector of a light emitting surface of the LED light source 1 is perpendicularly incident to a main scanning direction cross-section of the diffusion surface of the diffusion member 2 and is obliquely incident to a sub-scanning direction cross-section. There are also provided an original document reading device and an image forming apparatus having the original document reading device.

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.

  In recent years, development of light emitting diodes (hereinafter referred to as “LEDs”) has been actively conducted. The brightness of the LED element is rapidly increasing, and the cost is decreasing. LEDs generally have advantages such as long life, high efficiency, high G resistance, and monochromatic light emission, and are expected to be applied in many lighting fields. One of the uses is a document illumination device of a document reading device such as a digital copying machine or an image scanner.

The emission spectrum of the white light emitting LED element covers the visible wavelength band, and can be used for a document illumination device of a document reading device capable of reading a color image. For this reason, a wide variety of document illumination devices using white LEDs have been proposed.
Further, when the LED is used as a light source, the higher the illumination efficiency, the higher the energy saving effect. Therefore, it is important from the environmental viewpoint to provide a reading illumination system (original illumination device) having a high illumination efficiency using the LED light source.

LED elements used as a light source for illuminating the document surface are mounted on a substrate and mounted in rows at a predetermined interval in the main scanning direction. A configuration has also been proposed in which the pitch of the peripheral portions in the main scanning direction is shortened by setting the arrangement pitch of the LED elements to be non-uniform.
The LED element includes a blue light emitting chip and a phosphor for converting blue light emitted from the blue light emitting chip into yellow light. Part of the blue light emitted from the blue light-emitting chip 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 to produce pseudo white Light is generated.

  The size of the blue light emitting chip of the pseudo white LED is considerably smaller than the size of the phosphor that converts the wavelength to yellow light, and the light emission position is also different, so that the chromaticity of the illumination light varies on the original reading surface. It was easy. On the other hand, a method of diffusing both blue light and yellow light by a phosphor by a diffusion means such as a diffusion sheet is known in order to eliminate chromaticity variation.

  Since the orientation characteristic of the pseudo white light emitted from the LED element is generally isotropic, when the diffusion characteristic of the diffusion sheet is isotropic, a normal vector perpendicular to the LED light emitting surface is perpendicular to the diffusion sheet. In this case, the irradiation pattern on the original surface subjected to the sheet diffusing action is substantially concentric. On the other hand, the case where the diffusion characteristic of a diffusion sheet has anisotropy is demonstrated below.

An anisotropic diffusion sheet has a characteristic in which the diffusivity in two orthogonal directions on the diffusion surface is different. The surface of the diffusion surface has a fine uneven shape, and there is a type in which the direction in which the uneven pitch is short and the direction in which the long direction is orthogonal. The diffusivity in the short pitch direction increases and the diffusivity in the long direction decreases. The diffusion rate may be indicated by a diffusion angle. The diffusion angle refers to a position at which the half value of the peak value (center luminance) in the illuminance distribution of the diffuse illumination light is represented by the full width radiation full angle.

  Regarding the diffusion characteristics of the anisotropic diffusion sheet, for example, when a parallel light beam having a diameter of 5 mm is vertically incident on an anisotropic diffusion sheet having a diffusion angle of 30 degrees × 5 degrees, the distance from the sheet to the irradiation surface is 30 mm. In this case, the irradiation pattern on the irradiation surface spreads to about 35 mm in the main scanning direction, but is slightly over 5 mm in the sub-scanning direction and does not change much. In addition, when a parallel light beam having a diameter of 5 mm is vertically incident on an anisotropic diffusion sheet having a diffusion characteristic of 60 degrees × 1 degree, when the distance from the sheet to the irradiation surface is 30 mm, the irradiation pattern on the irradiation surface is: Although it spreads to 85 mm in the main scanning direction, the sub-scanning direction is slightly over 5 mm, and there is not much change.

  In the case of such an anisotropic diffusion sheet, as shown in FIGS. 1 (A) and 1 (B), when the normal line of the LED element 1 is arranged so as to be perpendicularly incident on the diffusion sheet 2, the diffusion action is achieved. The illuminance distribution of the irradiation pattern that receives and irradiates the document surface has an elliptical shape. Here, the anisotropic diffusion sheet has a strong diffusing action received from the anisotropic diffusion sheet, and when the direction of the wide diffusion angle is the long axis of the anisotropy, the long axis direction coincides with the main scanning direction of the scanner. Is arranged, the major axis direction of the elliptical irradiation pattern coincides with the main scanning direction as shown in FIG. By using an anisotropic diffusion sheet having a large diffusion angle in the main scanning direction, an elliptical irradiation pattern that is long in the main scanning direction is generated. Since the LED elements are arranged in the main scanning direction as shown in FIG. 1B, as shown in FIGS. 1B and 1C, some of the adjacent LED illumination patterns are in the main scanning direction. Since they overlap in the direction, an apparently line-shaped illumination pattern is formed in the main scanning direction. And since the irradiation patterns of the individual LED elements overlap in the main scanning direction, the white illumination area of the adjacent elliptical illumination pattern overlaps the yellow illumination area generated at the peripheral edge of the elliptical illumination pattern, so that the white color The degree is improved. If the diffusion angle in the long axis direction is wide, the ellipticity irradiation patterns of two or more LEDs adjacent in the arrangement direction overlap each other, so that the whiteness is further improved.

  A document illumination device including such an anisotropic diffusion sheet is known (for example, see Patent Document 1). Patent Document 1 discloses a document illumination device including an elliptical diffuser plate. An illumination pattern of an LED element that is elliptical in the main scanning direction (see FIG. 6B of Patent Document 1), and a normal line of a light emitting surface of the LED. A configuration is shown in which the vector is reflected by the end face of the light guide and is incident on the diffusion sheet perpendicularly (see FIG. 8A of Patent Document 1).

  However, in the document illumination device of Patent Document 1, the elliptical irradiation pattern is superimposed in the main scanning direction, but the irradiation patterns of individual LED elements are not superimposed in the sub-scanning direction.

  Here, the illuminance distribution of the blue light and the yellow light emitted from the LED elements will be described with reference to FIG. As shown in FIG. 5, the illuminance distribution of blue light attenuates in both directions in the sub-scanning direction in the sub-scanning direction of the original irradiation surface (blue 2), and the illuminance distribution of yellow light is also in the sub-scanning direction. Shows a characteristic that attenuates in both directions (yellow 2). At this time, the width in the sub-scanning direction in which the illuminance of yellow light is zero is wider than the width in the sub-scanning direction in which the illuminance of blue light is zero. It is known that this is because the phosphor that emits yellow light is larger than the light emitting surface size of the LED chip that emits blue light. For this reason, even if the irradiation pattern is ovalized in the main scanning direction, the blue component is lost and only the yellow component remains at the end in the sub-scanning direction, so that it does not become white.

  In other words, in the document illumination device described in Patent Document 1, there is a problem that even if the irradiation pattern is ovalized in the main scanning direction, the white area in the sub-scanning direction does not widen and the color unevenness in the sub-scanning direction is not improved.

  Accordingly, an object of the present invention is to provide an original illuminating device that is excellent in the effect of reducing color unevenness in an illumination area in the sub-scanning direction and that can provide a wider white illumination area, an original reading apparatus including the original illuminating apparatus, and image formation Is to provide a device.

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,
Document illumination comprising: a light emitting unit composed of a plurality of LED light sources arranged along the main scanning direction of a light irradiation region irradiated with light; and a diffusion member provided between the light emitting unit and the document reading surface Has a unit,
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 light emission is such that the normal vector of the light emitting surface of the LED light source is perpendicularly incident on the cross section in the main scanning direction of the diffusing surface of the diffusing member and is inclined with respect to the cross section in the sub scanning direction. The document illumination device is characterized in that a part and the diffusing member are arranged.
[2] The angle [theta] where the normal vector of the light emitting surface of the LED light source is incident on the cross section in the sub-scanning direction of the diffusing surface of the diffusing member is [theta] <60 [deg.]. The document illumination device described in 1.
[3] The [1] or the above, wherein the first direction and the second direction on the diffusion surface of the diffusion member are arranged so as not to coincide with the main scanning direction of the light irradiation region The document illumination device according to [2].
[4] Any one of [1] to [3], wherein the original illumination unit is provided in one of the sub-scanning directions with respect to the center of the light irradiation region in the sub-scanning direction, and the reflecting member is provided in the other. The document illumination device according to claim 1.
[5] When the center position of the axis X in the sub-scanning direction of the light irradiation region is X0, the surface that includes the axis Y in the main scanning direction of the light irradiation region including X0 and is perpendicular to the document reading surface The document illumination device according to any one of [1] to [3], wherein the document illumination unit is arranged symmetrically with respect to P in the sub-scanning direction.
[6] The absolute value of the angle formed by the second direction of the diffusing member and the axis Y in the main scanning direction of the light irradiation region is equal in each of the original illumination units arranged symmetrically. The document illumination device according to [5].
[7] The length of the normal vector from the light emitting surface of the LED light source to the center position X0 of the axis X in the sub-scanning direction of the light irradiation region is equal in each of the original illumination units arranged symmetrically. The document illumination device according to [5] or [6] above.
[8] A holding member for fixing the diffusing member is provided, the diffusing member has a holding and fixing region at an end, and the diffusing member is fixed to the holding member through the holding and fixing region. The document illumination device according to any one of [1] to [7].
[9] The document illumination device according to any one of [1] to [8],
Information on the original illuminated by the original illumination device is imaged on the image sensor via the first, second, and third reflecting mirrors and the imaging lens, and a light reception signal from the image sensor is converted into an electrical signal. A first traveling body that converts and reads and holds the original illumination device and the first reflection mirror, and a second traveling body that retains the second reflection mirror and the third reflection mirror. An original reading apparatus that scans at a speed ratio of 2: 1 and reads information on the original.
[10] The document illumination device according to any one of [1] to [8],
Information on a document illuminated by the document illumination device is imaged on an image sensor via at least one reflection mirror and an imaging lens, and a light reception signal from the image sensor is converted into an electrical signal and read. An original reading apparatus, wherein the original illuminating device, the reflection mirror, the imaging lens, and the imaging element are held by one traveling body, and the traveling body is scanned to read information on the original. .
[11] An image forming apparatus comprising the document reading device according to [9] or [10].

As an effect of the present invention, according to the first aspect of the present invention, there is provided a document illuminating device for irradiating a document reading surface of a document reading device with a plurality of LEDs arranged along the main scanning direction of the light irradiation region. A document illumination unit including a light emitting unit including a light source, and a diffusion member provided between the light emitting unit and the document reading surface, the diffusion member having a diffusion rate in a first direction on the diffusion surface; Is an anisotropic diffusing member having a large diffusivity in the second direction orthogonal to the first direction, and the normal vector of the light emitting surface of the LED light source is a cross section in the main scanning direction of the diffusing surface of the diffusing member. Is an original illumination device in which the light emitting unit and the diffusing member are arranged so as to enter perpendicularly and incline with respect to the cross section in the sub-scanning direction. The pattern is converted into a fan shape and Spread color illumination region, is excellent in reduction of color unevenness, it is possible to read the document with respect to displacement of the reading position is excellent in stability of color balance. Further, since this is equivalent to the ability to loosen the accuracy of the reading optical system (for example, tolerance of axial deviation, etc.), it is possible to reduce the cost of apparatus parts and assembly.
According to a second aspect of the present invention, in the original illuminating device according to the first aspect, an angle θ at which a normal vector of the light emitting surface of the LED light source is incident on a sub-scanning direction cross section of the diffusing surface of the diffusing member. However, since θ <60 °, it is possible to perform illumination with excellent depth characteristics of the illuminance distribution by appropriately arranging the main illumination angle with respect to the document reading surface. Sufficient light irradiation can be performed even on a document in a state where the portion is lifted.
According to a third aspect of the present invention, in the original illumination device according to the first or second aspect, the first direction and the second direction on the diffusing surface of the diffusing member are a main scanning direction of the light irradiation region. Therefore, the white illumination area in the sub-scanning direction can be greatly expanded, and the reading position dynamics in the sub-scanning direction due to static deviation or vibration of the reading optical system can be expanded. Even with respect to misalignment, it is possible to read a document with a stable color balance.
According to a fourth aspect of the present invention, in the document illumination device according to any one of the first to third aspects, the document illumination unit is provided on one side in the sub-scanning direction with respect to the center of the light irradiation region in the sub-scanning direction. Since the other side is provided with a reflecting member, it is possible to perform counter-illumination. For example, when reading a document having a step, illumination reflected light from the step portion is received by the image sensor, and the step portion does not become a shadow line. .
According to a fifth aspect of the present invention, in the document illuminating device according to any one of the first to third aspects, when the center position of the axis X in the sub-scanning direction of the light irradiation region is set to X0, the X0 includes the X0. Since the original illumination unit is arranged symmetrically in the sub-scanning direction with respect to the plane P including the axis Y in the main scanning direction of the light irradiation area and perpendicular to the original reading surface, a light source is also provided on the counter illumination side. The number of LED elements that can be mounted can be doubled, and the document surface can be illuminated with high illuminance, so that the scanning speed of scanning can be increased and the medium and high speed machines that require high illuminance illumination. Can be applied.
According to the invention of claim 6, in the document illumination device according to claim 5, the absolute value of the angle formed by the second direction of the diffusing member and the axis Y in the main scanning direction of the light irradiation region is set. Since each original illumination unit arranged symmetrically is the same, the distribution of chromaticity can be made symmetric with respect to the center of the light irradiation region in the sub-scanning direction, and the white illumination region in the sub-scanning direction can be made more The reading can be greatly expanded, and it is easy to read a document with a stable color balance even with respect to a dynamic shift in the sub-scanning direction of the reading position due to a static shift or vibration of the reading optical system.
According to the invention of claim 7, in the document illumination device according to claim 5 or 6, the normal vector from the light emitting surface of the LED light source to the center position X0 of the axis X in the sub-scanning direction of the light irradiation region. Are equal in each of the original illumination units arranged symmetrically, the symmetry of the illumination characteristic in the sub-scanning direction is increased, the white illumination area can be further widened, and the color in the sub-scanning direction is increased. The symmetry of the degree distribution can also be maintained, so even if a dynamic deviation in the sub-scanning direction of the reading position due to static deviation or vibration of the reading optical system occurs on either side of the sub-scanning direction Correction is easy and document reading with stable color balance can be performed.
According to an eighth aspect of the present invention, in the original illuminating device according to any one of the first to seventh aspects, the holding member for fixing the diffusing member is provided, and the diffusing member has a holding and fixing region at an end thereof. In addition, since the diffusion member is fixed to the holding member via the holding and fixing region, the width of the effective illumination region in the sub-scanning direction can be adjusted, and the diffusion member is fixed to the traveling body with high accuracy. In addition, since the deflection of the surface can be prevented, stable document reading can be performed even if vibration occurs as the traveling body moves.
According to a ninth aspect of the present invention, the document illumination device according to any one of the first to eighth aspects is provided, and information on the document illuminated by the document illumination device is converted into first, second, and third reflections. A first traveling which forms an image on an image sensor via a mirror and an imaging lens, converts a light reception signal from the image sensor into an electric signal, reads the electric signal, and holds the original illumination device and the first reflection mirror. And a second traveling body that holds the second reflecting mirror and the third reflecting mirror at a speed ratio of 2: 1 to read the document information, It is possible to realize document reading that is resistant to static positional deviation of the optical system and fluctuations of the received light signal on the imaging surface due to dynamic positional fluctuations.
According to a tenth aspect of the present invention, the document illumination device according to any one of the first to eighth aspects is provided, and information on the document illuminated by the document illumination device is converted into at least one reflection mirror and an imaging lens. The image is formed on the image sensor via the image sensor, and the received light signal from the image sensor is converted into an electric signal for reading, and the document illumination device, the reflection mirror, the image forming lens, and the image sensor are combined with one traveling body. Since the document reading device holds and scans the traveling body to read the information of the document, the document illumination device, the reflection mirror, the imaging lens, and the image sensor are held by one traveling body. An image reading apparatus that is resistant to fluctuations in the light reception signal on the imaging surface due to static position deviation of the system and dynamic position fluctuations, and that is small in size and has little signal noise that accompanies scanning scanning drive. realizable.
According to the eleventh aspect of the present invention, since the image forming apparatus includes the document reading device according to the ninth or tenth aspect, the color unevenness is effectively reduced in the illumination area in the sub-scanning direction, and a wider white illumination area. And an image forming apparatus capable of stable document reading can be realized.

(A) and (B) are schematic views showing a configuration of a main part of a conventional document illumination device, and (C) is an irradiation pattern on a document reading surface. (A) and (B) are schematic views showing a configuration of a main part in one embodiment of the document illumination device of the present invention, and (C) is an irradiation pattern on the document reading surface. It is the irradiation pattern which overlapped with the main scanning direction by the conventional original illuminating device. It is explanatory drawing which shows the example of the irradiation pattern by the original document illuminating device of this invention. FIG. 5 is a schematic diagram showing illuminance distributions of blue light and yellow light in a sub-scanning direction section A-A ′ of the white illumination area shown in FIG. 4. Explanation showing an example in which the first direction (short axis) and the second direction (major axis) of the anisotropic diffusion sheet are arranged so as not to coincide with the main scanning direction and sub-scanning direction axes of the light irradiation region. FIG. (A) and (B) are schematic views showing a configuration of a main part in another embodiment of the document illumination device of the present invention, and (C) is an irradiation pattern on the document reading surface. It is explanatory drawing which shows the irradiation pattern when the symmetrical line A-A 'rotates to the state inclined in the main scanning axis direction with respect to the sub scanning direction. It is a schematic block diagram which shows the structure of the principal part in other embodiment of the original document illuminating device of this invention. It is a schematic block diagram which shows the structure of the principal part in other embodiment of the original document illuminating device of this invention. It is a schematic block diagram which shows the structure of the principal part in other embodiment of the original document illuminating device of this invention. It is a schematic block diagram which shows the structure of the principal part in other embodiment of the original document illuminating device of this invention. It is a schematic block diagram which shows the structure of the principal part in other embodiment of the original document illuminating device of invention. It is a schematic block diagram which shows the structure of the principal part in other embodiment of the original document illuminating device of invention. It is explanatory drawing which shows the example of the irradiation pattern by the original document illuminating device of this invention. FIG. 16 is a schematic diagram illustrating illuminance distributions of blue light and yellow light in a sub-scanning direction section A-A ′ of the white illumination region in the irradiation pattern illustrated in FIG. 15. It is explanatory drawing which shows the example of the irradiation pattern by the original document illuminating device of this invention. FIG. 18 is a schematic diagram illustrating illuminance distributions of blue light and yellow light in a sub-scanning direction cross-section A-A ′ of the white illumination region in the irradiation pattern illustrated in FIG. 17. It is explanatory drawing which shows the example of the irradiation pattern by the original document illuminating device of this invention. It is explanatory drawing which shows the example of the irradiation pattern by the original document illuminating device of this invention. It is explanatory drawing which shows the example of the irradiation pattern by the original document illuminating device of this invention. 1 is a schematic diagram illustrating a configuration example of an embodiment of a document reading apparatus according to the present invention. It is a schematic diagram which shows the structural example of the other embodiment of this invention original reading apparatus. 1 is a schematic diagram showing an embodiment of an image forming apparatus of the present 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.

<Original illumination device>
FIG. 2A is an example of a schematic diagram of a configuration example of the document illumination device of the present invention. The document illuminating device of the present invention is provided between a light emitting unit composed of a plurality of LED light sources 1 disposed along the main scanning direction of the light irradiation region of the document reading surface 3 and between the light emitting unit and the document reading surface 3. The diffusing member 2 has a diffusivity in the second direction orthogonal to the first direction rather than the diffusivity in the first direction on the diffusing surface. The light emitting portion and the diffusing member 2 are large anisotropic diffusing members, and the normal vector of the light emitting surface of the LED light source 1 is incident perpendicularly to the cross section of the diffusing surface of the diffusing member 2 in the main scanning direction. And, it is arranged so as to be incident on the cross section in the sub-scanning direction at an angle.
Hereinafter, the diffusion rate is represented by a diffusion angle. The diffusion angle refers to a position at which the half value of the peak value (center luminance) in the illuminance distribution of the diffuse illumination light is represented by the full width radiation full angle.
The first direction and the second direction are a direction in which the diffusivity is large and a direction in which the diffusivity is large, and are a short axis and a long axis in elliptical diffusion. (Hereinafter, the first direction may be expressed as “short axis” and the second direction as “long axis”.)

[Embodiment 1]
As shown in FIG. 2 (A), the light-emitting portion constituting the original light source unit and the diffusion member (hereinafter also referred to as “anisotropic diffusion sheet”) 2 are combined with an LED light source (hereinafter referred to as “LED element”). A description will be given of a case where the normal vector of the light emitting surface of 1 is arranged so as to be incident at an angle θ (θ ≠ 0) with respect to the normal vector of the anisotropic diffusion sheet 2.

  As shown in FIG. 2A, the normal vector of the light emitting surface of the LED element 1 is obliquely incident on the anisotropic diffusion sheet 2, so that the original reading surface 3 formed by any one LED element 1 is displayed. The irradiation pattern can be changed from the conventional elliptical shape shown in FIG. 1C to the fan shape shown in FIG.

  In the conventional elliptical irradiation pattern shown in FIG. 1C, the width X1 in the sub-scanning direction of the irradiation pattern overlapped in the main scanning direction as shown in FIG. 3 was about 1 mm. On the other hand, when the oblique incidence is performed so that θ in FIG. 2A is 45 degrees, the width X2 of the white illumination area in the sub-scanning direction is expanded to 2 mm or more as shown in FIG. Thus, according to the document illumination device of the present invention, it is understood that the irradiation pattern is converted into a fan shape and the width of the white illumination area in the sub-scanning direction is widened.

  FIG. 5 schematically shows the illuminance distribution of the blue light and the yellow light in the sub-scanning direction section A-A ′ of the white illumination area shown in FIG. 4. In FIG. 5, the horizontal axis represents the sub-scanning direction corresponding to A-A ′ in FIG. 4, and the vertical axis represents illuminance. In the fan-shaped irradiation pattern in the center of FIG. 4, blue is blue 2 and yellow is yellow 2. On the other hand, the blue color of the left and right fan-shaped illumination patterns in FIG. 4 is blue 1, blue 3, yellow is yellow 1, and yellow 3. The blue components of the fan-shaped illumination pattern blue 2 of the blue component overlap the blue components of the fan-shaped illumination patterns Blue 1 and Blue 3 and the yellow components of Yellow 1 and Yellow 3. As described above, since the irradiation patterns are also overlapped in the sub-scanning direction, it can be seen that the width of the blue component in the sub-scanning direction X increases from X1 to X2, as shown in FIG.

  Further, as shown in FIG. 2B, the LED light sources 1 are arranged in the main scanning direction, so that the fan-shaped irradiation patterns overlap in the main scanning direction as shown in FIG. A linear illumination pattern is formed in the main scanning direction. In FIG. 2B, four LED elements 1 are schematically shown. However, in an apparatus for illuminating a document having an A4 to A3 size width, the arrangement of LED elements 1 arranged in the main scanning direction is shown. The number is larger than this, and is, for example, about 20 to 25 in the case of A4 size width (depending on the light emission power of the LED element).

  In the peripheral part of each fan-shaped irradiation pattern, the blue component is weak and the whiteness is low, but the areas with high whiteness of the fan-shaped irradiation patterns by other LED elements adjacent in the main scanning direction overlap. According to the document illumination device of the present invention, the uniformity of the whiteness in the main scanning direction is improved.

Specifically, when a parallel light beam having a diameter of 5 mm is vertically incident on the diffusing member 2 which is an anisotropic diffusing sheet having a light diffusing characteristic of 30 degrees × 5 degrees, the diffusing member 2 has a thickness of 30 mm from the irradiation surface 3. Although the irradiation width in the main scanning direction at a distance extends to about 35 mm, the irradiation width in the sub-scanning direction is hardly changed because the distance from the diffusing member 2 to the irradiation surface 3 is short, whereas the light flux is within the cross section in the sub-scanning direction. When the light is incident at an inclination angle of 45 degrees, the irradiation width in the sub-scanning direction is expanded to about 10 mm.
Further, when a parallel light beam having a diameter of 5 mm is incident on the diffusion member 2 that is an anisotropic diffusion sheet having a light diffusion characteristic of 60 degrees × 1 degree, main scanning at a distance of 30 mm from the irradiation surface 3 from the diffusion member 2 is performed. Although the irradiation width in the direction extends to about 85 mm, the irradiation width in the sub-scanning direction is hardly changed because the distance from the scattering member 2 to the irradiation surface 3 is short, whereas the light flux is 45 in the cross section in the sub-scanning direction. When the light is incident at an inclination angle of 20 degrees, the irradiation width in the sub-scanning direction is expanded to about 15 mm.

[Embodiment 2]
A mode in which the first direction and the second direction on the diffusion surface of the anisotropic diffusion sheet 2 are arranged so as not to coincide with the main scanning direction of the light irradiation region as shown in FIG. 6 will be described. .

  In FIG. 6, the major axis of the anisotropic diffusion sheet is indicated by the Y ′ axis, and the main scanning direction of the light irradiation region is indicated by the Y axis. The radius of the elliptical shape of elliptical diffusion corresponds to the high diffusion rate. In the example shown in FIG. 6, the Y ′ axis is inclined with respect to the Y axis by an angle φ (about 45 degrees). At this time, the arrangement of the original illumination unit is shown in FIGS. 7A and 7B, and the irradiation pattern on the original reading surface by any one LED element 1 is shown in FIG. 7C. As shown in FIG. 7C, the fan-shaped irradiation pattern is inclined as compared with FIG.

  Further, as shown in FIG. 8, the fan-shaped irradiation pattern is obtained by rotating the symmetry line AA ′ so as to be inclined in the main scanning axis direction with respect to the sub-scanning direction. The length in the sub-scanning direction becomes longer. When tilted 45 degrees as shown in FIG. 8, the width X3 is about 1.4 times longer than X2. For this reason, the white illumination area in the sub-scanning direction becomes wider than in the case of the first embodiment.

  Since the LED elements 1 are arranged in the main scanning direction Y as shown in FIG. 7B, the rotated fan-shaped irradiation pattern is arranged in the main scanning direction as shown in FIG. Are overlapped with each other, and a linear irradiation pattern is formed. In the peripheral part of each fan-shaped irradiation pattern, the blue component is weak and the whiteness is low, but the areas with high whiteness of the fan-shaped irradiation patterns by other LED elements adjacent in the main scanning direction overlap. According to the document illumination device of the present invention, the uniformity of the whiteness in the main scanning direction is improved.

Specifically, the diffusion member 2 that is an anisotropic diffusion sheet having a light diffusion characteristic of 30 degrees × 5 degrees is arranged with its long axis rotated by 45 degrees with respect to the main scanning direction of the irradiation region, and a diameter of 5 mm. When a parallel light beam is vertically incident, the irradiation width in the main scanning direction at a distance of 30 mm from the irradiating surface 3 from the diffusing member 2 is expanded to about 25 mm, and the irradiation width in the sub-scanning direction is about 7 mm. When the light beam is incident at an inclination angle of 45 degrees within the cross section in the sub-scanning direction, the irradiation width in the sub-scanning direction is expanded to about 14 mm.
Further, when the anisotropic diffusion sheet 2 having a light diffusion characteristic of 60 degrees × 1 degree is arranged with its major axis rotated by 45 degrees with respect to the main scanning direction of the irradiation region, and a parallel light beam having a diameter of 5 mm is incident The irradiation width in the main scanning direction at a distance of 30 mm from the irradiating surface 3 extends from the diffusing member 2 to about 85 mm, but the irradiation width in the sub-scanning direction is almost the same because the distance from the scattering member 2 to the irradiating surface 3 is short. On the other hand, when the light beam is incident at an inclination angle of 45 degrees in the cross section in the sub-scanning direction, the irradiation width in the sub-scanning direction is expanded to about 21 mm.

[Embodiment 3]
The arrangement of the document illumination unit will be described with reference to FIG. As shown in FIG. 9, the LED element 1 is disposed at a position where the normal vector of the light emitting surface crosses the vicinity of the center of the document reading surface 3, and the anisotropic diffusion sheet 2 is disposed substantially horizontally with the document table 4. ing. Since the normal vector of the light emitting surface of the LED element 1 satisfies the condition of entering obliquely with respect to the anisotropic diffusion sheet 2, the effects shown in the first and second embodiments can be obtained. Further, by arranging the long axis of the anisotropic diffusion sheet 2 so as not to coincide with the main scanning direction but to be inclined in the sub-scanning direction, the effect shown in the above-described embodiment 2 can be obtained.

  With such an arrangement, for example, when the user looks into the light source from the document surface side, the array of light emitting LED elements 1 is not a light emitting point array but a line-shaped light emitter, so that the user's retina The light energy density which reaches | attains can reduce significantly and the safety | security with respect to a user can be improved.

  Further, as shown in FIG. 9, counter illumination is realized by providing a document illumination unit on one side and a counter reflection mirror 6 as a reflection member on the other side with respect to the center of the light irradiation region 5 in the sub-scanning direction. By providing the anisotropic diffusion sheet 2 between the counter reflection mirror 6 and the original reading surface, an effect of widening the white illumination area in the sub-scanning direction can be obtained even for the counter illumination light.

[Embodiment 4]
The LED element 1 is configured and disposed at a position where the normal vector of the light emitting surface of the LED element 1 crosses the vicinity of the center of the document reading surface, and the anisotropic diffusion sheet 2 may be disposed substantially perpendicular to the document reading surface. it can. In this case, since the diffusion surface of the anisotropic diffusion sheet 2 does not face the original reading surface, the illumination light reflected by the original reading surface does not return to the diffusion surface of the anisotropic diffusion sheet 2 and re-reflect. There is an advantage that flare light does not occur. The less the flare light, the lower the black level of the image.

[Embodiment 5]
An example in which means for deflecting the illumination optical path is disposed between the LED element 1 and the anisotropic diffusion sheet 2 is shown in FIG. In FIG. 13, a reflecting surface 8 is provided as a deflecting means. The LED element 1 can also be arranged so that the normal vector of the light emitting surface is horizontal with the document reading surface by adjusting the angle and curvature shape of the reflecting surface 8. With such an arrangement, the thickness of the original illumination device in the direction perpendicular to the original reading surface can be reduced. The number of reflective surfaces 8 is not limited to one, and may be a plurality of surfaces.

  Moreover, the light guide member 7 shown in FIG. 11 and FIG. 12 can also be used instead of the reflective surface 8 shown in FIG. The light from the LED element 1 optically coupled from the incident surface of the light guide member 7 is guided through the light guide member 7 to the exit surface while satisfying the internal total reflection condition. It is guided to the surface.

  The shape of the light guide member 7 may be a shape in which the incident end face and the exit end face are not parallel. For example, a shape in which the normal line of the incident end face is in the sub-scanning direction and the normal line of the outgoing end face is inclined toward the document reading surface side can be realized by design. The main point of the design is to increase the light guide efficiency to the output end face by adjusting the way of bending the end face so that the light beam satisfies the total reflection condition. There are also research reports, which are known techniques.

[Embodiment 6]
In the configuration example shown in FIGS. 9, 11, and 13, the document illumination unit including the LED element 1 and the anisotropic diffusion sheet 2 on one side in the sub-scanning direction with respect to the center of the light irradiation region 5 in the sub-scanning direction. In addition, a reflection member is provided on the other side. By adopting such a configuration, it is possible to illuminate the document from both sides, and it is difficult to cause shadows on the step portion particularly when reading a document with a step.

[Embodiment 7]
In the configuration examples shown in FIGS. 10, 12, and 14, the original illumination unit (FIG. 14 is a schematic diagram) including the LED element 1 and the anisotropic diffusion sheet 2 symmetrically with respect to the center of the light irradiation region 5 in the sub-scanning direction. In this configuration, the width of the white illumination area on the original reading surface can be increased in the sub-scanning direction, and the irradiation pattern is further increased in the main scanning direction. By overlapping, the uniformity of whiteness increases. That is, when the center position of the axis X in the sub-scanning direction of the light irradiation region 5 is X0, the surface P including the axis Y in the main scanning direction of the light irradiation region 5 including X0 and perpendicular to the document reading surface. On the other hand, it is preferable that the document illumination units are arranged symmetrically in the sub-scanning direction. In particular, with such a configuration, a large number of LED arrays can be mounted, so that higher illuminance can be obtained and it can be applied to a document reading apparatus with a high reading speed. Further, the original can be illuminated from both sides, and the shadow of the stepped portion is less likely to occur particularly when reading an original having a step.

  Further, it is preferable that the absolute value of the angle formed by the long axis of the anisotropic diffusion sheet 2 and the axis Y in the main scanning direction of the light irradiation region 5 is equal in each of the original illumination units arranged symmetrically. With this arrangement, the irradiation pattern becomes a pattern having good symmetry with respect to the sub-scanning direction as shown in FIG.

The irradiation pattern shown in FIG. 15 is a pattern in which the irradiation pattern shown in FIG. 4 and the pattern obtained by vertically inverting the irradiation pattern in FIG. 4 overlap. FIG. 16 schematically shows illuminance distribution characteristics in the sub-scanning direction in the irradiation pattern of FIG.
The characteristic shown in FIG. 16 is a characteristic in which the characteristic shown in FIG. 5 and the characteristic obtained by inverting the characteristic shown in FIG. The width in the sub-scanning direction in which the blue component exists is indicated by X4. The symmetry in the sub-scanning direction in FIG. 16 is superior to that in FIG.

[Embodiment 8]
It is preferable that the lengths of the normal vectors from the light emitting surface of the LED light source 1 to the center position X0 of the axis X of the light irradiation region 5 in the sub-scanning direction are equal in the respective document illumination units arranged symmetrically.
The distance from the position where the normal of the light emitting surface of the LED light source 1 provided on the negative side to X0 intersects the original reading surface to X0 is ΔXL, the method of the light emitting surface of the LED light source 1 provided on the positive side from X0 FIG. 17 schematically shows an irradiation pattern when the position of the intersection is shifted so that ΔXL and ΔXR are equal, where ΔXR is the distance from the position where the line intersects the document reading surface to X0. In FIG. 17, the illumination width X5 in the sub-scanning direction is wider than X4 compared to FIG. FIG. 18 schematically shows the illuminance distribution characteristic in the sub-scanning direction at this time. In FIG. 18, the width in the sub-scanning direction of the white irradiation region where the blue component exists is indicated by X5. Compared to X4 in FIG. 16, it can be seen that X4 <X5.

[Embodiment 9]
FIG. 19 shows a document illuminating apparatus in which document illumination units are arranged symmetrically with respect to the center of the light irradiation area 5 in the sub-scanning direction. The anisotropic diffusion sheet 2 of each document illumination unit is irradiated with light on the long axis. An irradiation pattern is schematically shown in the case where the regions 5 are arranged to be inclined with respect to the main scanning direction and the angles formed by the axis Y in the main scanning direction are equal. Comparing the sub-scanning direction irradiation width X6 in FIG. 19 with the sub-scanning direction irradiation width X4 in FIG. 15 which is an irradiation pattern when the axis of the anisotropic diffusion sheet is not tilted, it can be seen that X4 <X6.

[Embodiment 10]
FIG. 20 shows a document illumination device in which document illumination units are arranged symmetrically with respect to the center of the light irradiation area 5 in the sub-scanning direction, and the long axis of the anisotropic diffusion sheet 2 of each document illumination unit is irradiated with light. Each original illumination in which the length of the normal vector to the center position X0 of the axis X in the sub-scanning direction of the light irradiation area 5 is arranged symmetrically with respect to the main scanning direction of the area 5 is arranged. It is preferred that the units are equal. The distance from the position where the normal of the light emitting surface of the LED light source 1 provided on the negative side to X0 intersects the original reading surface to X0 is ΔXL, the method of the light emitting surface of the LED light source 1 provided on the positive side from X0 When the distance from the position where the line intersects the original reading surface to X0 is ΔXR, the intersection position is shifted so that ΔXL and ΔXR are equal. Therefore, the irradiation width X7 in the sub-scanning direction is the width shown in FIG. It is even wider than X6.

[Embodiment 11]
FIG. 21 shows a document illuminating apparatus in which document illumination units are arranged symmetrically with respect to the center of the light irradiation region 5 in the sub-scanning direction, and the long axis of the anisotropic diffusion sheet 2 of each document illumination unit is irradiated with light. An irradiation pattern in which the absolute values of the angles φ1 and φ2 formed by the region 5 are inclined with respect to the main scanning direction and the axis Y in the main scanning direction are equal, specifically, φ2 = −φ1. This is shown schematically. A pattern different from the irradiation pattern shown in FIG. 19 is obtained.
FIG. 21 shows an LED light source in which the distance from the position where the normal line of the light emitting surface of the LED light source 1 provided on the negative side to X0 intersects the original reading surface to X0 is on the positive side of ΔXL and X0. When the distance from the position where the normal of the light emitting surface of 1 intersects the original reading surface to X0 is ΔXR, the intersection position is shifted so that ΔXL and ΔXR are equal. Therefore, the irradiation width X8 in the sub-scanning direction is It is wider than the width X6 shown in FIG.

[Embodiment 12]
The anisotropic diffusion sheet 2 preferably has a long shape that is long in the main scanning direction, but has a holding and fixing region at an end portion outside the region where the light guide diffusion action is required. preferable. The holding member is preferably fixed to a high-strength holding member through the holding and fixing region, and may be fixed directly to the holding member on the holding member, or indirectly through an adhesive means such as an adhesive. It may be held and fixed. In particular, when a film-like sheet is used as the anisotropic diffusion sheet 2, it is preferable that the surface of the holding and fixing region on the sheet side and the surface of the holding member are bonded and fixed without bending. For example, there is a method in which a stretching force is applied to the film side, and the holding member is pressure-bonded in a state where a predetermined tension is applied to bond the bonding surfaces together. Here, if the tension is too strong, the shape and diffusion characteristics of the diffusion surface may change, and the film may shrink after adhesion and the adhesion surface may be peeled off. Therefore, it is necessary to adjust the tension. On the other hand, when the film is thick, it can be bonded and fixed without particularly stretching.
Further, it is preferable that the holding member of the anisotropic diffusion sheet 2 is provided with a holding connection portion with a traveling body of a document reading apparatus described later.

<Document reader>
[Embodiment 13]
FIG. 22 shows an example of an embodiment of a document reading apparatus provided with the document illumination device of the present invention.
Information on the document 18 illuminated by the document illumination device of the present invention is transferred onto the image sensor 11 via the first reflecting mirror 14, the second reflecting mirror 15, the third reflecting mirror 16 and the imaging lens 10. An image is formed, and a light reception signal from the image sensor 11 is converted into an electric signal and read. The first traveling body 13 that holds the document illumination device and the first reflecting mirror 14 and the second traveling body 17 that holds the second reflecting mirror 15 and the third reflecting mirror 16 are 2: 1. The information of the original 18 is read by scanning at a speed ratio. An example of the image sensor 11 is a CCD.
Note that the LED light sources 1 are preferably arranged at regular intervals in the main scanning direction.

  By scanning the first traveling body 13 and the second traveling body 17 at a speed ratio of 2: 1 and reading information on the document 18, the optical path length from the document surface to the image sensor, that is, the conjugate of the reading optical system. Reading scanning can be performed while keeping the length constant. Since the document illumination device of the present invention is thinned, the document reading device can also be configured to be thin and compact.

  In addition, since the area where the illuminance distribution in the sub-scanning direction is flat is wide, installation errors of optical elements such as reflection mirrors and imaging lenses and dynamic fluctuations associated with scanning drive are allowed on the light-receiving surface of the image sensor. It is possible to realize a device having excellent stability of the received light signal. In other words, the tolerance of these optical elements can be relaxed, and the cost of apparatus parts and assembly can be reduced.

[Embodiment 14]
FIG. 23 shows an example of another embodiment of a document reading apparatus provided with the document illumination device of the present invention.
The information of the original illuminated by the original illumination device of the present invention is imaged on the image sensor 11 via at least one reflection mirror 9 and the imaging lens 10, and the light reception signal from the image sensor 11 is converted into an electrical signal. The document illumination device, the reflecting mirror 9, the imaging lens 10, and the image sensor 11 are held by a single traveling body 12, and the traveling body 12 is scanned to read information on the document on the document table 4. read. Note that the LED light sources 1 are preferably arranged at regular intervals in the main scanning direction.

  In the document reading apparatus shown in FIG. 23, since it is not necessary to drive the reflection mirror at the time of scanning reading, the drive mechanism apparatus can be simplified, and the entire apparatus can be reduced in size and weight. Even if vibration or the like occurs when the traveling body 12 is driven to scan, the relative positional deviation between the document illumination device, the reading optical system (the reflection mirror 9 and the imaging lens 10), and the image sensor 11 is not described above. 22 is further reduced as compared with the original reading apparatus shown in FIG. 22, and the optical signal characteristics received on the light receiving surface of the image sensor 11 are stabilized. Since the document illumination device of the present invention is thinned, the document reading device can also be configured to be thin and compact.

<Image forming apparatus>
An image forming apparatus according to the present invention includes at least the document illumination device according to the present invention described above, and includes the document reading device according to the present invention. The configuration and operation of the image forming apparatus of the present invention will be described below.
FIG. 24 is a schematic front view showing the internal structure of a full-color copying machine 101 according to an embodiment of the present invention. An image forming unit 103 for forming a color image is provided at the center of the apparatus main body 102 of the copying machine 101. The image forming unit 103 includes four drum-shaped photosensitive members 104 that are spaced apart at equal intervals and arranged in parallel in the horizontal direction, a charging roller 105 that uniformly charges the outer peripheral surface of the photosensitive member 104, and a charging roller 105. An exposure device 106 that forms an electrostatic latent image by exposing the outer peripheral surface of each of the photosensitive members 104 charged in accordance with 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 107 that visualizes the toner image, an intermediate transfer belt 108 onto which the toner image on the photoconductor 104 is sequentially transferred, and a cleaning that removes toner remaining on the photoconductor 104 after the transfer of the toner image onto the intermediate transfer belt 108. The apparatus 109 includes a transfer roller 110 that transfers the toner image transferred onto the intermediate transfer belt 108 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 104, and the toner images of these colors are formed on the intermediate transfer belt 108. By being transferred, a color toner image is formed on the intermediate transfer belt 108, and this color toner image is transferred to the recording medium S.

In the upper part of the apparatus main body 102, an ADF 111 for automatically feeding a document, a contact glass 112 on which the document is placed, and a document automatically fed by the ADF 111 or a document placed on the contact glass 112 are read. A document reading device 113 is arranged.
The document reading device 113 includes first and second traveling bodies 114 and 115 capable of traveling at a speed of 2: 1 in parallel with the contact glass 112, a lens 116, a CCD 117 serving as an image reading unit, and the like. The first traveling body 114 is reflected on the document surface by the document illumination device 118 of the present invention for illuminating the document surface of the document placed on the contact glass 112 or the document conveyed by the ADF 111. A first mirror 119 that reflects the reading light traveling along the reading optical axis is mounted. A second mirror 120 and a third mirror 121 that further reflect the light reflected by the first mirror 119 are mounted on the second traveling body 115. A lens 116 and a CCD 117 are disposed in front of the reading light sequentially reflected by the first to third mirrors 119, 120, and 121 in the traveling direction.

  A plurality of, for example, four-stage paper cassettes 124 for storing the recording medium S are provided at the lower part of the apparatus main body 102. The recording media S stored in these paper cassettes 124 are separated and fed one by one by the pick-up roller 125 and the feed roller 126, and the separated and fed recording media S are conveyed by the paper provided in the apparatus main body 102. It is conveyed along the path 127. On the sheet conveyance path 127, a registration roller 128, a transfer roller 110, a fixing device 129, a paper discharge roller 130, and the like are arranged.

  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 106 according to the reading result by the document reading device 113, An electrostatic latent image is formed by exposing the outer peripheral surface of each photoconductor 104 to which the laser light is uniformly charged by the charging roller 105. Each color toner is supplied from each developing device 107 to the electrostatic latent image, whereby a toner image of each color is formed. The toner image on each photoconductor 104 is sequentially transferred onto an intermediate transfer belt 108 that moves in synchronization with the photoconductor 104, and a color toner image is formed on the intermediate transfer belt 108.

  On the other hand, when the image forming operation in the image forming unit 103 is started, the recording medium S starts to be separated and fed from the sheet cassette 124 and is separated and fed on the sheet conveyance path 127. Is transferred to a transfer position between the intermediate transfer belt 108 and the transfer roller 110 by a registration roller 128 that is driven to rotate intermittently.

Next, the registration roller 128 is rotationally driven, and the recording medium S is sent between the intermediate transfer belt 108 and the transfer roller 110, whereby the color toner image on the intermediate transfer belt 108 is transferred onto the recording medium S. The color toner image transferred onto the recording medium S is fixed to the recording medium S while the recording medium S passes through the fixing device 129, and the recording medium S on which the color toner image is fixed is discharged by the paper discharge roller 130. The paper is discharged onto the tray 131.
The document reading device 113 can be operated independently as a scanner device.

1 LED light source (LED element)
2 Diffusion member (anisotropic diffusion sheet)
3 Document reading surface (irradiated surface)
4 Document table 5 Document reading area (light irradiation area)

JP 2009-246462 A

Claims (11)

A document illumination device for irradiating a document reading surface of a document reading device with light,
Document illumination comprising: a light emitting unit composed of a plurality of LED light sources arranged along the main scanning direction of a light irradiation region irradiated with light; and a diffusion member provided between the light emitting unit and the document reading surface Has a unit,
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 light emission is such that the normal vector of the light emitting surface of the LED light source is perpendicularly incident on the cross section in the main scanning direction of the diffusing surface of the diffusing member and is inclined with respect to the cross section in the sub scanning direction. A document illuminating apparatus comprising a diffusing member and a diffusing member.   2. The document according to claim 1, wherein an angle θ in which a normal vector of a light emitting surface of the LED light source is incident on a cross section in a sub-scanning direction of the diffusion surface of the diffusion member is θ <60 °. Lighting device.   3. The device according to claim 1, wherein the first direction and the second direction on a diffusion surface of the diffusion member are arranged so as not to coincide with a main scanning direction of the light irradiation region. Document illumination device.   4. The document illumination according to claim 1, wherein the document illumination unit is provided on one side in the sub-scanning direction with respect to the center of the light irradiation region in the sub-scanning direction, and a reflection member is provided on the other side. apparatus.   When the center position of the axis X in the sub-scanning direction of the light irradiation region is X0, the surface P includes the axis Y in the main scanning direction of the light irradiation region including X0 and is perpendicular to the document reading surface. 4. The document illumination device according to claim 1, wherein the document illumination unit is arranged symmetrically in the sub-scanning direction.   The absolute value of the angle formed by the second direction of the diffusing member and the axis Y in the main scanning direction of the light irradiation region is equal in each of the original illumination units arranged symmetrically. Item 6. The document illumination device according to Item 5.   The length of the normal vector from the light emitting surface of the LED light source to the center position X0 of the axis X in the sub-scanning direction of the light irradiation region is equal in each of the original illumination units arranged symmetrically. The document illumination device according to claim 5 or 6.   A holding member for fixing the diffusing member is provided, the diffusing member has a holding and fixing region at an end, and the diffusing member is fixed to the holding member through the holding and fixing region. The document illumination device according to claim 1. The document illumination device according to any one of claims 1 to 8, comprising:
Information on the original illuminated by the original illumination device is imaged on the image sensor via the first, second, and third reflecting mirrors and the imaging lens, and a light reception signal from the image sensor is converted into an electrical signal. A first traveling body that converts and reads and holds the original illumination device and the first reflection mirror, and a second traveling body that retains the second reflection mirror and the third reflection mirror. An original reading apparatus that reads information on the original by scanning at a speed ratio of 2: 1. The document illumination device according to any one of claims 1 to 8, comprising:
Information on a document illuminated by the document illumination device is imaged on an image sensor via at least one reflection mirror and an imaging lens, and a light reception signal from the image sensor is converted into an electrical signal and read. An original reading apparatus, wherein the original illuminating device, the reflection mirror, the imaging lens, and the imaging element are held by a single traveling body, and the traveling body is scanned to read information on the original.   An image forming apparatus comprising the document reading device according to claim 9.

Images