JP2013090197A - Illuminating device and image forming device - Google Patents

Abstract

It is necessary to dispose these reflecting member and light guide so that the reflecting surface of the reflecting member is positioned above the upper end of the light guide.
According to one embodiment, a light source that illuminates a reading region of an image by transmitted light, the light of the light source is guided in a longitudinal direction, the light is directly emitted in the direction of the reading region, and the light is emitted. A light guide body that has a light diffusion surface portion that crosses the longitudinal direction and is emitted in a direction different from the direction of the reading area and diffuses or reflects the light, and is emitted from the light diffusion surface portion and linear in the longitudinal direction. And having a reflecting surface that reflects the emitted light beam having a longitudinal section toward the reading region, is provided to face the light guide, and locally has a predetermined illuminance over the longitudinal direction on the reflecting surface. And a reflecting member in which the height position of the light receiving surface region where the light distribution is distributed is equal to or lower than the upper end height of the light guide.
[Selection] Figure 3

Description

  One embodiment relates to an illumination device and an image forming apparatus.

  An image reading apparatus used in a digital copying machine reads an image for one line in the main scanning direction. The image reading apparatus irradiates a document from a light source with linear light along the main scanning direction in a longitudinal section, collects reflected light from the document by a lens or the like, and enters the image sensor or the like. .

  The image reading apparatus uses an illumination device. In order to prevent the shadow from being generated due to the unevenness of the image, the illuminating device has a mechanism for returning the light beam outside the image reading area to the reading area. Conventionally, a platen glass, a light guide body having a longitudinal light guide body and a light source such as a light emitting element provided at an end of the light guide body, and a linear emission from the light guide body in a longitudinal section There is known an illuminating device that includes a reflecting member that reflects a light beam to an image reading region and is disposed on a side opposite to the light guide with respect to the image reading region (see, for example, Patent Document 1).

JP 2010-252340 A

  However, in the above-described conventional technology, it is necessary to arrange the reflecting member and the light guide so that the reflecting surface of the reflecting member is positioned above the upper end of the light guide.

  Due to the restriction that the reflecting surface must be arranged higher than the upper end of the light guide, the illumination device cannot take an arrangement in which the light guide is close to the platen glass.

  In order to solve such a problem, according to one embodiment, a light source that illuminates an image reading area by transmitted light, and the light of the light source is guided in a longitudinal direction, and the light is emitted directly in the direction of the reading area. The light is emitted from the light diffusing surface portion, the light guide having a light diffusing surface portion that crosses the longitudinal direction and emits the light in a direction different from the direction of the reading region, and diffuses or reflects the light. A reflective surface for reflecting the outgoing light flux having a linear longitudinal section in the longitudinal direction toward the reading region; and provided to face the light guide, and locally on the reflective surface in the longitudinal direction. And a reflecting member in which the height position of the light receiving surface region in which a predetermined illuminance is distributed is less than or equal to the upper end height of the light guide.

1 is a configuration diagram of an image forming apparatus according to a first embodiment. It is a figure which shows the structural example of the image reading apparatus containing the illuminating device which concerns on 1st Embodiment. It is a figure which shows the longitudinal cross-section structure orthogonal to the main scanning direction of the illuminating device which concerns on 1st Embodiment. It is a figure which shows the longitudinal cross-section structure orthogonal to the main scanning direction of the illuminating device which concerns on 2nd Embodiment.

  Hereinafter, an illumination device and an image forming apparatus according to embodiments will be described with reference to FIGS. 1 to 4. In the drawings, the same portions are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
The illuminating device according to the first embodiment is an illuminating device that illuminates a document to be inserted into an image reading apparatus. The image forming apparatus according to the first embodiment is a digital copying machine having a scanner.

  FIG. 1 is a block diagram of a digital copying machine. The digital copying machine 10 includes a main body 11, a scanner 12 (image reading device), an image processing unit 13, a printing unit 14, a fixing unit 15, a paper feeding unit 16, a transport mechanism 17, a secondary transfer unit 18, a controller 19, and a document transport unit. 20. The scanner 12 scans the document surface and outputs image data. The image processing unit 13 converts the three color image data from the scanner 12 into four print colors, and corrects the image data.

  The printing unit 14 forms an image on the sheet and outputs the sheet. The printing unit 14 includes a belt 21, an image forming process unit 22Y for yellow (Y), an image forming process unit 22M for magenta (M), an image forming process unit 22C for cyan (C), and a black (K). Image forming process unit 22K and laser exposure device 23. The belt 21 is an intermediate transfer belt. A driving roller 29 drives the belt 21.

  The image forming process unit 22Y includes a photosensitive drum 24, a charger 25, a developing device 26, a primary transfer roller 27, and a static eliminator 28. The photosensitive drum 24 includes a drum that is driven to rotate clockwise and a photosensitive member on the outer peripheral surface of the drum. The charger 25 charges the photosensitive drum 24. The charger 25 changes the amount of charge on the photosensitive drum 24. The developing device 26 develops the electrostatic latent image on the photosensitive drum 24. The developing device 26 has a magnet roller in a container filled with a two-component developer. Both the magnet roller and the photosensitive drum 24 rotate, and the developing device 26 supplies toner to the electrostatic latent image with a magnetic brush. Further, the primary transfer roller 27 transfers the toner image on the photosensitive drum 24 onto the belt 21 at the downstream side in the drum rotation direction. The static eliminator 28 removes charges on the photosensitive drum 24. The configuration of the image forming process units 22M, 22C, and 22K is substantially the same as the configuration of the image forming process unit 22Y.

  The fixing device 15 fixes an unfixed toner image on the sheet. Each of the sheet feeding units 16 has a sheet set therein. The transport mechanism 17 supplies the sheet from the paper feeding unit 16 to the printing unit 14. The secondary transfer unit 18 transfers the toner image on the belt 21 to the sheet. The fixing unit 15 heats and pressurizes the sheet from the secondary transfer unit 18. The transport mechanism 17 discharges the fixed sheet to a discharge tray in the main body 11.

  The controller 19 includes a CPU (central processing unit), ROM (read only memory), RAM (random access memory), and a bus line that connects the CPU, ROM, and RAM. The controller 19 controls an image forming process by the printing unit 14 including the scanner 12. The ROM stores the control contents of the scanner 12. The RAM temporarily stores various data calculated by the CPU.

  The digital copying machine 10 or the scanner 12 has an original table glass 30 (original table) on the upper part of the main body 11. The document glass 30 places a document and generates an image to be read by scattered light from the document. The document table glass 30 has a main surface having a reading area and a back surface opposite to the main surface. The document feeder 20 is provided above the document table glass 30 and inserts the document into the scanner 12. The document transport unit 20 transports a bundle of documents one by one onto the document table glass 30 and positions the documents on the document table glass 30. An automatic document feeder (ADF) is used for the document feeder 20.

  The scanner 12 will be further described. FIG. 2 is a diagram illustrating a configuration example of the scanner 12. In the figure, the above-mentioned reference numerals represent the same elements. The scanner 12 scans the document D sent by the document transport unit 20 or the document surface placed on the document table glass 30. The scanner 12 converts the read image information into an analog signal. The scanner 12 illuminates the document surface, scans the document surface in the main scanning direction and the sub-scanning direction, and generates an optical image. The main scanning direction refers to the main body depth direction of the main body 11. The sub-scanning direction refers to a direction orthogonal to the main scanning direction.

  The scanner 12 includes a lighting device 31 (lighting device according to the present embodiment) and a first carriage 32 that moves left and right, a second carriage 33 that is moved in a direction opposite to the moving direction of the first carriage 32, a lens 34, A CCD (charge coupled device) sensor 35 and a drive motor 36 are provided. The platen cover 37 is a part of the document conveying unit 20. Based on the information input to the CCD sensor 35, the laser exposure device 23 emits laser light for creating an electrostatic latent image on the photosensitive drum 24.

  FIG. 3 is a view showing a longitudinal sectional structure of the illumination device 31 orthogonal to the main scanning direction. The above described symbols represent the same elements. As shown in FIGS. 2 and 3, the illumination device 31 includes a light source 38 that illuminates an image reading region P by light transmitted through the platen glass 30, and directs the light from the light source 38 in the longitudinal direction. A light guide 39 that is orthogonal to the direction of the region P and the longitudinal direction and is emitted in a direction different from the direction of the reading region P, a light diffusion surface portion 40 that is formed on the light guide 39 and diffuses or reflects light, and a light diffusion surface portion 40. And a reflecting member 42 having a reflecting surface 41 that reflects the outgoing light flux having a longitudinal longitudinal section in the longitudinal direction toward the reading region P. The height position of the light receiving surface region R where high illuminance is locally distributed in the longitudinal direction on the reflection surface 41 of the reflection member 42 is the same as the upper end height position of the light guide 39 or the light guide 39. The upper end height position is lower than the upper end height position. That is, the height position of the light receiving surface region R in which the predetermined illuminance is locally distributed in the longitudinal direction on the reflection surface 41 of the reflection member 42 is equal to or less than the upper end height of the light guide 39. The predetermined illuminance means that the illuminance is sufficient when reading a document.

  The light source 38 is provided on one end surface of the light guide 39 in the longitudinal direction, for example, one end surface on the front side of the main body. For example, a light source unit is used as the light source 38. The light source unit includes a substrate and one or a plurality of light emitting diodes (LEDs) attached on the substrate, and light is incident from one end surface of the light guide 39 from the light emitting diodes.

  The light guide 39 has a main scanning direction as a longitudinal direction, guides a light source luminous flux in the longitudinal direction, and emits the luminous flux from at least two light exit surfaces that are long in the longitudinal direction. The light guide 39 includes a light guide body 43 that is long in the main scanning direction and guides light in the longitudinal direction, and a case member 44 that covers a part of the light guide body 43. The light guide body 43 is made of a transparent medium. The light guide body 43 is a molded product of resin or optical glass having a high light transmittance such as acrylic or polycarbonate. Specifically, a light guide prism is used for the light guide body 43. The case member 44 is a metal plate having a high light reflectance. For the case member 44, for example, a white resin and a member having a surface coated with a paint are used. Alternatively, a metal plate having a high reflectance is used for the case member 44, and specifically, an aluminum plate, a stainless plate, or the like can be used. The light guide 39 may have a structure in which the case member 44 and the reflection member 42 are integrated.

  The light guide 39 further includes a light reflection area 45 that reflects light from the light source 38, a first emission surface 46 that faces the light reflection area 45 and emits reflected light as direct light in the direction of the reading area P, and a longitudinal direction. And a second exit surface 47 that emits light in the direction of the reflecting member 42. The light reflection region 45 is, for example, a minute uneven processing or a printed pattern. The first exit surface 46 and the second exit surface 47 are exposed portions of the light guide body 43 that are not covered by the case member 44, and both are long in the main scanning direction. The light guide 39 has a polyhedral structure. The cross-sectional shape of the longitudinal section perpendicular to the main scanning direction of the light guide 39 is a polygonal shape. That is, the light guide 39 has a side surface in the longitudinal direction corresponding to the main scanning direction as the first emission surface 46, and the light reflection region 45 is formed on the surface facing the first emission surface 46.

  The light diffusing surface portion 40 is a surface region or part that diffuses or reflects light and emits a light beam toward the second exit surface 47. The light diffusion surface portion 40 has a light scattering structure. The light scattering structure refers to, for example, a narrow groove, a substantially hemispherical unevenness, or a printed pattern. The light diffusion surface portion 40 is formed on the light guide main body 43 side, for example. The light diffusion surface portion 40 is formed on the light guide 39 so as to face the second exit surface 47.

  The reflection member 42 is provided to face the light guide 39 on the lower surface 48 side of the document table glass 30. The reflection surface 41 of the reflection member 42 reflects the emitted light beam emitted from the light diffusion surface portion 40 through the second emission surface 47 toward the upper reading region P. This outgoing light beam is a planar light beam having a linear longitudinal section in the longitudinal direction. For the reflection surface 41, a glossy member having high light reflection characteristics is used. In the present embodiment, the height position of the light receiving surface region R in which high illuminance is locally distributed in the longitudinal direction on the reflecting surface 41 is the surface height of the first exit surface 46 (the upper end height of the light guide). ) Or substantially lower than the surface height of the first exit surface 46. On the reflecting surface 41, a predetermined illuminance distribution is generated in the longitudinal direction. FIG. 3 shows an illuminance distribution characteristic D drawn on the assumption that the illuminance distribution on the reflection surface 41 is visualized in the longitudinal section. The illuminance distribution characteristic D has a peak locally. The light receiving surface region R is a rectangular region in which high illuminance is distributed in the peak direction in the longitudinal direction.

  The light diffusion surface portion 40 is inclined with respect to the vertical surface. The light diffusing surface portion 40 is inclined so that the orthogonal surface of the light diffusing surface portion 40 including the main scanning direction axis faces downward with respect to the horizontal plane. Alternatively, the light diffusing surface portion 40 directs the diffused light downward at an acute diffusion angle with respect to the horizontal plane by the light scattering structure. The inclination of the light diffusing surface 40 itself, or the optical axis of the diffused light is directed downward from the horizontal plane, or the optical axis of the light emitted from the light diffusing surface 40 due to both this inclination and this orientation is the sub-scanning direction. It is substantially parallel or faces downward from a horizontal plane. Accordingly, the height of the light receiving surface region R is substantially the same as the surface height of the first exit surface 46 or is positioned below the surface height.

  Further, the reflecting member 42 is disposed with respect to the document table glass 30 and the light guide 39 so as to be positioned at the same level as or below the upper end of the light guide 39. Here, when the shortest distance between the first exit surface 46 of the light guide 39 and the back surface of the original platen glass 30 is L1, and the shortest distance between the backside of the original platen glass 30 and the upper end of the reflecting surface is L2, illumination is performed. In the apparatus 31, the document table glass 30, the light guide 39, and the reflection member 42 are arranged so that L1 ≦ L2. L1 is a value determined in advance to keep the light guide 39 in a non-contact manner. L <b> 2 is a value that allows the amount of direct light from the first exit surface 46 and the amount of reflected light from the second exit surface 47 to be uniformly determined on the main surface of the platen glass 30.

  Further, the first carriage 32 and the second carriage 33 constituting the scanner 12 of FIG. 2 receive the reciprocating driving force from the driving motor 36 in opposite directions via a belt or a pulley, and the glass of the document table glass 30. It is designed to move parallel to the surface.

  The first carriage 32 has a folding mirror 49 that is provided along the reading optical axis and guides reflected light from the original. The second carriage 33 has mirrors 50 and 51 for turning back, and these mirrors 50 and 51 are moved by a driving force. As the first carriage 32 and the second carriage 33 move in the sub-scanning direction, the reading position P for the document moves from left to right. These mirrors 50 and 51 are provided on the second carriage 33 so that the surface normal of the mirror 50 and the surface normal of the mirror 51 are orthogonal to each other. The mirror 51 guides the reflected light from the mirror 50 to the lens 34. The lens 34 is an imaging lens that collects reflected light, and forms an image of the light beam on the surface of the CCD sensor 35.

  The CCD sensor 35 receives light information reflected from the document. The CCD sensor 35 includes, for example, four lines of line sensors, and outputs a monochrome image signal and RGB color image signals to the image processing unit 13. A stepping motor is used as the drive motor 36. The drive motor 36 is driven by a pulse signal from the controller 19.

  Among the controls of the controller 19, the scanner control system includes a CCD sensor control circuit that controls the CCD sensor 35, a light source control circuit that controls the illumination device 31 that irradiates light on the document, a motor control circuit that controls the drive motor 36, An image correction unit that stores data such as shading correction and gamma correction, and an image processing unit 12 that performs image processing such as enlargement / reduction processing and resolution conversion on the data input from the CCD sensor 35. Are connected by bus. The scanner control system includes a display device control circuit that controls a display device on which a document reading condition setting screen and the like are displayed, and a key panel 58 that includes a reading start button for instructing reading start and other buttons for setting other resolutions. A key panel control circuit for controlling, and an interface for sending data processed by the image processing unit to the outside of the scanner control system and receiving instruction information from the outside of the scanner control system. Yes.

  The document is sent by the document transport unit 20 to the scanner 12 including the illumination device 31 having the above-described configuration. Alternatively, a person opens the platen cover 37 and places a document on the platen glass 30. In FIG. 2, the document D is placed on the document table glass 30 with the surface to be read facing down. By closing the platen cover 37, the document D is pressed onto the document table glass 30.

  The scanner 12 starts an illumination operation by an operation input to the key panel 58. In FIG. 3, the light emitted from the light source 38 enters the light guide 39. The light guide body 43 travels in the longitudinal direction while totally reflecting light waves traveling inside the light guide body 43 at the boundary surface between the light guide body 43 and the air. The light wave traveling inside the light guide 39 hits the light diffusion surface portion 40, and the light wave is emitted from the first emission surface 46 and the second emission surface 47 to the outside of the light guide body 43.

  At this time, the optical axis of the light beam emitted from the first exit surface 46 is directed to the document table glass 30 and directly toward the reading region P. On the other hand, the optical axis of the light beam emitted from the second exit surface 47 is directed to the reflecting member 42 and travels toward the reading region P through the reflecting member 42. At this time, if a line having high local illuminance among the light beams emitted from the second exit surface 47 is the optical axis of the light beam, the optical axis is substantially parallel to the sub-scanning direction or directed downward from the sub-scanning direction. Therefore, the illuminating device 31 can arrange | position the reflection member 42 below the light guide body light source (the light source 38 and the light guide 39). The lighting device 31 also satisfies the relationship L1 ≦ L2.

  Further, the light amount of the direct light beam from the first exit surface 46 and the light amount of the reflected light beam from the second exit surface 47 are superimposed in the image reading area P on the platen glass 30. 3, if the document table glass 30 is cut along a vertical plane perpendicular to the sub-scanning direction (the reading optical axis in FIG. 3 corresponds to a straight line when the vertical plane is viewed from the front side of the main body toward the rear side of the main body. The indirect reflected light beam is mainly irradiated toward the upper left direction, and the direct light beam is irradiated mainly toward the upper right direction. Since the CCD sensor 35 has a sensitivity range in the sub-scanning direction, a light distribution is generated by light beams from two directions in the image reading region P on the upper surface of the platen glass 30. By superimposing the light distribution, the reproducibility of a pair of left and right page images is enhanced by, for example, a copy of a book in a spread state in the sub scanning direction. Furthermore, since the illumination area in the sub-scanning direction can have a predetermined width, errors that occur when the components of the scanner 12 or the document move are absorbed.

  The illumination device 31 irradiates the original with linear light that is long in the main scanning direction from the light source 38. The illumination device 31 irradiates the original D onto the line in the longitudinal direction. The mirrors 49, 50, and 51 return the reflected light from the document D, respectively. The mirror 49 causes the reflected light to enter the CCD sensor 35 via the lens 34. The scanner 12 reads an image for one line in the main scanning direction. The scanner control system drives and controls the first carriage 32 and the second carriage 33 so that the optical path length from the document surface to the CCD sensor 35 is always constant. The scanner control system controls the speed by the drive motor 36 so that the sub-scanning speed of the first carriage 32: the sub-scanning speed of the second carriage 33 is 2: 1. The scanner control system synchronizes the drive motor 36 with the read timing signal and moves the first carriage 32 from the left to the right in FIG. Reflected light from the illumination device 31 is scanned on the document in the sub-scanning direction.

The document D placed on the document table glass 30 is sequentially read for each main scanning image area in the CCD sensor 35. The CCD sensor 35 performs photoelectric conversion into a signal corresponding to the light intensity that is reflected light from the document. At this time, the relationship of the following formulas (1) and (2) is established between each element and the output voltage from the photoelectrically converted CCD sensor 35 and the moving speed of the first carriage 32.
E = S × I × α × t (1)
V = 0.0254 / (t × R) (2)
Here, E represents the output value (V) of the CCD sensor 35, and S represents the sensitivity V / (lx · s) of the CCD sensor 35. I represents the illuminance (lx) of the document surface. α represents an illuminance reduction coefficient from the illuminance on the original surface to the CCD sensor 35. This α has a value in consideration of the reflectance of the original, the same reflectance between the mirrors 49 to 51 of the mirrors 49 to 51, the transmittance of the lens 34, and the like. t represents the processing time (s) per line. V represents the speed (m / s) of the first carriage 32. R represents the reading resolution (dpi). “×” and “•” represent multiplication.

  Thus, the reflecting member 42 and the light guide 39 can be disposed so that the reflecting member 42 is located below the first exit surface 46 of the light guide 39. When the first carriage 32 and the second carriage 33 reciprocate, contact between the illumination device 31 and the document table glass 30 can be avoided. The lighting device 31 uses a single light source 38 to adjust the balance of each light quantity between the direct light and the reflected light and to secure the light quantity of the reflected light while bringing the reflecting member 42 as close as possible to the lower surface of the glass. become able to.

  Generally, it is desirable that the direct light from the light guide light source and the indirect light from the reflecting member have the same illuminance. In the conventional example, in order to obtain sufficient illuminance of indirect light, L1 and L2 are related by L1> L2. Therefore, in the conventional example, it is difficult to bring the light guide light source close to the platen glass in order to increase the illumination efficiency.

  On the other hand, in the illuminating device 31, since the relationship of L1 ≦ L2 is established as shown in FIG. 3, the margin between the upper end of the reflecting member 42 and the lower surface of the document table glass 30 can be reduced. The light has a characteristic that the light intensity falls according to the optical path distance. The illumination device 31 can bring the light source of the light guide body as close as possible to the document table glass 30 without the illumination device 31 and the document table glass 30 being in contact with each other. The illuminating device 31 can illuminate the document surface without increasing the optical path distance, and the illumination efficiency of the light source 38 can be improved.

  In addition, the value of L1 is set in advance so that the lighting device 31 does not hit the platen glass 30 even if tolerances of individual parts of the lighting device 31, assembly tolerances of these components, vibration of the drive motor 36, etc. occur. By deciding, when the scanner 12 reads an image, the illumination device 31 does not contact the platen glass 30 even if the first carriage 32 and the second carriage 33 move.

  The illumination device 31 has one light guide light source (light guide 39 and light source 38). Since there is only one light guide light source, the illuminating device 31 evenly distributes the light amount of direct light and the light amount of reflected light that is indirect light in the reading region P to suppress the intensity of illumination and variations in illuminance. . The illuminating device 31 lowers the upper end of the reflecting surface 41, and brings the light guide 39 toward the document table glass 30 so that the upper end of the reflecting surface 41 is lower than the surface height of the first exit surface 46 of the light guide 39. Can be arranged. The balance of each light quantity can be adjusted, and the light quantity of the light beam toward the reflecting member 42 out of the light flux from the light guide 39 can be secured.

  Since the light guide 39 approaches the original platen glass 30, the light intensity is prevented from decreasing according to the fourth power of the optical path distance, and the illumination efficiency by the light guide light source can be improved. In the conventional example, since the reflecting surface protrudes upward, the light source of the light guide cannot be disposed close to the platen glass without contacting the light source of the light guide and the platen glass.

  According to the illuminating device and the image forming apparatus according to the present embodiment, the illuminating device 31 can be used as a document while maintaining the illumination efficiency of the light guide light source high without causing the reflecting member 42 and the document table glass 30 to contact each other. It becomes possible to take an arrangement close to the table glass 30.

(Second Embodiment)
The lighting device according to the embodiment may use a light guide having a shape different from the shape of the light guide 39. In the first embodiment, direct light and reflected light are emitted in two directions from one light diffusion surface portion 40 in the polyhedral structure. The illuminating device according to the second embodiment has two light diffusing surface portions corresponding to the light diffusing surface portion 40, respectively. In the present embodiment, only one light diffusing surface portion 40 is emitted in that one light diffusing surface portion directly emits light to the reading region P and the other light diffusing surface portion emits a light beam for indirect light to the reflecting member 42. This is different from the first embodiment. An illuminating device according to the second embodiment is an illuminating device for a document to the scanner 12. The image forming apparatus according to the second embodiment is a digital copying machine 10. Other than these, the illumination device and the image forming apparatus according to the present embodiment have substantially the same configuration as the example of the first embodiment.

  FIG. 4 is a view showing a longitudinal sectional structure orthogonal to the main scanning direction of the illumination device according to the present embodiment. The above described symbols represent the same elements.

  The illuminating device 52 includes a light source 38 (FIG. 2) that illuminates an image reading area P by light transmitted through the platen glass 30, and a light guide body 53 that guides the light source light in the longitudinal direction. Light guide 54 that is directly orthogonal to the direction and longitudinal direction of the reading region P and is emitted in a direction different from the direction of the reading region P, and a light diffusion surface portion 55 that diffuses or reflects light respectively formed on the light guide 54. First light diffusing surface portion) and light diffusing surface portion 56 (second light diffusing surface portion), and an emitted light beam having a longitudinal longitudinal line shape emitted from these light diffusing surface portions 55 and 56 is directed to reading region P. And a reflecting member 42 that has a reflecting surface 41 that reflects light and is provided to face the light guide 54. The upper end height position of the light receiving surface region R where high illuminance is locally distributed in the longitudinal direction on the reflecting surface 41 of the reflecting member 42 is the same as or lower than the height of the upper surface of the light guide 54. It is supposed to become. The light guide 54 is formed with an emission surface 57 that directly emits light in the direction of the reading region P. The light diffusion surface portions 55 and 56 are curved surfaces that reflect or diffuse light.

  In the illumination device 52 having such a configuration, the light guide 54 has at least two light diffusion surface portions 55 and 56. The light emitted from the light source 38 is incident from one or both of one end surface in the longitudinal direction of the light guide 54 and the other end surface. The light travels through the light guide 54 in the longitudinal direction while being reflected inside the light guide 54. Light traveling inside the light guide 54 strikes the light diffusion surface portions 55 and 56. The light guide 54 emits this light from the emission surface 57 to the outside.

  At this time, the optical axis of the light beam from the first light diffusion surface portion 51 is directed to the document table glass 30, and this light beam is directed directly to the reading region P. On the other hand, the optical axis of the light beam from the second light diffusion surface portion 52 is directed to the reflecting member 42, and this light beam is directed to the reading region P through the reflecting member 42. At this time, among the light beams emitted from the exit surface 57, if a line with locally strong illuminance is used as the optical axis of the light beam, the optical axis is substantially parallel to the sub-scanning direction or directed downward from the sub-scanning direction. The illuminating device 52 can arrange | position the reflection member 42 below the light guide light source (the light source 38 and the light guide 54). The illumination device 52 can satisfy L1 ≦ L2.

(Other)
The above-described embodiment is not limited to the embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage.

  The illumination devices 31 and 52 may be configured as an image forming apparatus in combination with the printing unit 14. Here, the image forming apparatus refers to, for example, a digital multifunction peripheral, an MFP (multi function peripheral), or a color printer.

  In the above embodiment, the light source 38 is provided on the front side of the light guide 39, but the light source 38 may be provided on one end surface of the light guide 39 on the rear side of the main body. The light source 38 may be provided on both end faces of the light guide 39. The shape of the sub-scan section is not limited to that shown in FIG.

  A resin material may be used as the transparent document table. The case member 44 is a metal plate, but may be used as long as it reflects light, such as a reflective paint applied to the inner wall surface of the case member 44. When the light guide body 43 uses a medium capable of totally reflecting light, the case member 44 for covering the light guide body 43 is not necessarily provided. In the reflecting member 42, the reflecting surface 41 and a portion other than the reflecting surface 41 may be configured by separate members. In this case, the illuminating device according to the embodiment uses the shortest distance between the upper end of the reflecting surface 41 and the original table glass 30 as the shortest distance L2 between the reflecting member 42 and the original table glass 30. A reflective paint may be applied to the reflective surface 41. The reflecting surface 41 can be a concave surface or a convex surface instead of a flat surface. The light diffusing surface portions 55 and 56 may have fine irregularities on the surface or may be formed into a polyhedral shape.

  In this embodiment, the scanner 23 has been described as a part of the image forming apparatus. However, the present invention is not limited to this, and the scanner 23 itself may be defined as an image forming apparatus.

  Although several embodiments have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Digital copying machine (image forming apparatus), 12 ... Scanner, 14 ... Printing part, 23 ... Laser exposure apparatus, 38 ... Light source, 39 ... Light guide, 40 ... Light diffusion surface part, 41 ... Reflecting surface, 42 ... Reflection Member, 43 ... Light guide body, 45 ... Light reflection region, 46 ... First exit surface, 47 ... Second exit surface, 52 ... Illuminating device, 53 ... Light guide body, 54 ... Light guide, 55 ... Light diffusion surface portion (First light diffusion surface portion), 56... Light diffusion surface portion (second light diffusion surface portion).

Claims (5)

A light source that illuminates an image reading area by transmitted light;
The light from this light source is guided in the longitudinal direction, the light is emitted directly in the direction of the reading area, the light is emitted in a direction crossing the longitudinal direction and different from the direction of the reading area, and the light is diffused or reflected. A light guide having a light diffusing surface portion formed thereon;
A reflection surface that reflects the emitted light beam emitted from the light diffusing surface portion and having a longitudinal longitudinal section in the longitudinal direction toward the reading region, and is provided opposite to the light guide, on the reflection surface; An illumination device comprising: a reflecting member having a light receiving surface region in which a predetermined or higher illuminance is locally distributed in the longitudinal direction and having a height position equal to or lower than an upper end height of the light guide. The image forming apparatus further includes a transparent document table that generates the image by scattered light from the document and has a main surface having the reading area and a back surface opposite to the main surface, and the light guide moves the light toward the reading area. A first emission surface for emitting and a second emission surface for emitting the light in the different directions;
The distance between the first exit surface of the light guide and the back surface of the document table in contact with the movement of the light guide is L1, and the distance between the first exit surface and the document table back surface is L1. On the main surface of the document table, the amount of direct light from the first exit surface and the amount of reflected light from the second exit surface are substantially equal between the back surface of the document table and the upper end of the reflection surface. 2. The illumination device according to claim 1, wherein when the distance is L2, the document table, the light guide, and the reflecting member are arranged so that L1 ≦ L2.   2. The light guide has a polyhedral structure including a plurality of surface portions, and the light diffusion surface portion includes at least two first light diffusion surface portions and second light diffusion surface portions having a light scattering structure. Or the illuminating device of Claim 2. A lighting device according to claim 1;
A mirror that reflects light reflected from the illumination device;
A charge coupled device that receives the light reflected by the mirror;
An image forming apparatus comprising:   5. The image forming apparatus according to claim 4, further comprising a laser exposure device that emits a laser beam for forming an electrostatic latent image on the photosensitive drum based on information input to the charge coupled device.

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