JP5047204B2 - Illumination apparatus, image reading apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to an illumination device, an image reading device, and an image forming device having a light source in which a plurality of light emitting elements are arranged on a substrate.

  In an image reading apparatus provided in an image forming apparatus such as a copying machine, a facsimile machine, and a digital multi-function peripheral, and an image reading apparatus connected to a computer via a communication means such as a network, an illumination device having a light source is generally used. The reflected light from the original illuminated by is read as an original image.

  Conventionally, as a light source provided in a lighting device, a rod-shaped light source such as a halogen lamp or a xenon lamp, or a light source in which a plurality of light emitting elements such as a light emitting diode (LED) are arranged on a substrate is used. There are things to do.

  Among these, when a light source in which a plurality of light emitting elements are arranged on a substrate is employed, further improvement in illuminance on the light irradiation surface of the document is required.

  In this regard, Patent Document 1 below discloses an LED surface light source device in which the upper surface of a substrate such as a PWB on which LED elements are arranged is printed in white.

JP 63-152183 A

  However, as with the substrate described in Patent Document 1, no matter how much the upper surface is printed in white, if various colored material layers (especially green resist layers) are provided thereon, the light irradiation surface of the document It is not possible to obtain satisfactory illuminance.

  For example, when using a light source in which a light-emitting element is mounted on a substrate having a green resist layer printed thereon and a green resist layer thereon, an actual test was performed on a 50-unit monochrome multifunction device. Since the illuminance on the irradiated surface was insufficient, a very good image could not be obtained. That is, the conventional light emitting element mounting substrate provided with the green resist layer has a problem that the effect of improving the illuminance is not expected.

  In addition, if the thickness of the white printing material provided on the conventional light emitting element mounting substrate is thin, the color of the substrate itself is transparent. For example, in the case of silk printing, the white printing material is applied in layers. In other words, there may be a problem that the cost increases accordingly.

  Accordingly, the present invention provides a lighting device, an image reading apparatus, and an image forming apparatus that are light sources that irradiate light toward a document and that include a light source formed by arranging a plurality of light emitting elements on a substrate. An object of the present invention is to provide an illuminating device, an image reading device, and an image forming apparatus capable of improving the illuminance on the light irradiation surface of the document.

In order to solve the above-described problems, the present invention provides a lighting device that includes a light source that irradiates light toward a document and includes a plurality of light-emitting elements arranged on a substrate. The resist layer of the substrate is white, and printing is performed on the resist layer. The white resist layer is used as a base, and the printing color is set to the plurality of light emitting elements. The illumination device is characterized in that the color is adapted to the chromaticity characteristics of the luminescent color from .

  The present invention also provides an image reading apparatus comprising the illumination device according to the present invention.

  The present invention also provides an image forming apparatus comprising the image reading apparatus according to the present invention.

  According to the illumination device, the image reading device, and the image forming apparatus according to the present invention, the resist layer on the substrate is not a green resist layer as in the related art but a white resist layer, and the white resist layer is Since the light reflectance is higher than that of other color resist layers such as green, for example, the reflection efficiency can be improved accordingly, and thereby the illuminance on the light irradiation surface of the document can be improved.

By the way , there are various chromaticity characteristics of the colors emitted from the light emitting elements, and it is necessary to adjust the amount of light of each color such as red, green, and blue in order to irradiate the original with a desired light emission color. For this reason, the adjustment work of the light quantity of a light emitting element has been complicated conventionally.

  In this regard, in the present invention, in the state where the resist layer as a base is white and the reflection efficiency is improved, the color of the printing is adapted to the chromaticity characteristics of the emission colors from the plurality of light emitting elements. By changing, the color of the light to be irradiated on the document is adjusted to the desired color by combining the light emission color from the plurality of light emitting elements and the printing color without adjusting the light amount of the light emitting element. can do. In this way, the color of the light to be irradiated on the document while improving the reflection efficiency can be achieved by simply changing the color of the printing with the white resist layer as a base without adjusting the light amount of the light emitting element. The desired color can be easily obtained.

  In the present invention, typical examples of the printing include silk printing (silk screen printing).

  By the way, in a light source formed by arranging a plurality of light emitting elements, the illuminance unevenness occurs on the light irradiation surface of the document due to a decrease in illuminance between the luminescent spots for each luminescent spot of the light emitting elements. As a result, in the formed image, for example, density unevenness in the arrangement direction or streaking in the direction orthogonal to the arrangement direction may occur.

  From this viewpoint, in the present invention, it is preferable that the white resist layer is used as a base and a diffusion layer is provided.

  In this specific matter, by providing the diffusion layer with the white resist layer as a base, it is possible to cause both the improvement of the reflection efficiency by the white resist layer and the diffusion by the diffusion layer, It is possible to alleviate or eliminate the occurrence of illuminance unevenness on the light irradiation surface of the document, and hence the density unevenness and streaks of the formed image, while improving the reflection efficiency.

The lighting device according to the present invention may be configured as the following aspects (a) to (d). That is,
(A) an aspect in which light emission from the plurality of light emitting elements is side light emission in which an optical axis is parallel to a substrate surface of the substrate;
(B) a mode in which the plurality of light emitting elements are arranged on only one side with reference to the optical path of the reflected light from the document;
(C) a mode in which the plurality of light emitting elements are arranged on both sides with respect to the optical path of the reflected light from the document,
(D) A mode in which at least two of the modes (a) to (c) are combined.

  In any of the aspects (a) to (d), the above-described effects can be obtained satisfactorily.

  In the present invention, a typical example of the light emitting element is a light emitting diode element.

  As described above, according to the present invention, the illumination device capable of improving the illuminance on the light irradiation surface of the document by making the resist layer of the substrate white instead of green as in the prior art, and An image reading apparatus and an image forming apparatus can be provided.

1 is a side view schematically showing an image forming apparatus including an image reading apparatus to which an embodiment of an illumination device according to the present invention is applied. It is a disassembled perspective view which shows schematic structure of the light source unit which is an example of the illuminating device which concerns on this embodiment. It is a figure which shows schematic structure of the light source in the light source unit shown in FIG. 2, Comprising: The figure (a) is a side view of a light source unit, and the figure (b) is a side view of a light source. It is a schematic side view which shows the other example of the light source in the light source unit shown in FIG.2 and FIG.3. It is a figure for demonstrating schematic structure of the board | substrate which mounts a light emitting element, Comprising: Fig. (A) is the longitudinal cross-sectional view, Fig. (B) is the top view, Fig. (C) is It is a figure which expands and shows a board | substrate corner | angular part in the state shown in figure (b). It is a figure for demonstrating the usage example which changes the color of a silk printing material according to the chromaticity characteristic of the luminescent color from a light emitting element, Comprising: (a) is an XY chromaticity diagram which shows a chromaticity coordinate on a plane. FIG. (B) is a diagram illustrating the color of the silk printing material. It is the figure which described the measurement result with the case where the board | substrate which made the color of the resist layer the conventional green and the board | substrate which made the color of the resist layer white was used. 5 is a cross-sectional view of another example of the substrate shown in FIG. 5, in which FIG. (A) is a diagram showing an example in which a diffusion layer is provided on a white resist layer, and FIG. It is a figure which shows the state by which light is diffused by the diffused layer. FIG. 7A is a graph showing the state of illuminance (bright spot) unevenness on the light irradiation surface of the document with respect to the distance in the main scanning direction, and FIG. 9A shows the state of illuminance unevenness when no diffusion layer is provided. FIG. 4B is a diagram illustrating a state of uneven illuminance when a diffusion layer is provided.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not.

  FIG. 1 is a side view schematically showing an image forming apparatus D including an image reading apparatus 200 to which an embodiment of an illumination apparatus according to the present invention is applied.

  An image forming apparatus D shown in FIG. 1 includes an image reading apparatus 200 that reads an image of a document, and a recording sheet such as plain paper in color or single color that is an image of a document read by the image reading apparatus 200 or an image received from the outside. And an apparatus main body A for recording and forming.

  In the image reading apparatus 200, when a document is set on the document setting tray 41, the pickup roller 44 is pressed against the surface of the document and rotated, the document is pulled out from the tray 41, and passes between the suction roller 45 and the separation pad 46. After being separated one by one, it is transported to the transport path 47.

  In the conveyance path 47, the leading edge of the document contacts the registration roller 49 and is aligned parallel to the registration roller 49, and then the document is conveyed by the registration roller 49 and passes between the reading guide 51 and the reading glass 52. At this time, light from the light source 211 of the illuminating device (here, the light source unit) 210 is applied to the light irradiation surface of the document through the reading glass 52, and the reflected light enters the light source unit 210 through the reading glass 52. The reflected light is reflected by the second and third mirrors 54a and 54b of the light source unit 210 and the mirror unit 54 and guided to the imaging lens 55. The imaging lens 55 converts the image of the light irradiation surface of the document into a CCD ( The image is formed on a charge coupled device 56. The CCD 56 reads an image on the light irradiation surface of the document and outputs image data indicating the image. Further, the document is conveyed by the conveyance roller 57 and is discharged to the paper discharge tray 59 via the paper discharge roller 58.

  Further, the image reading apparatus 200 can read a document placed on the document table glass 61. The registration roller 49, the reading guide 51, the paper discharge tray 59, and the like, and the members above them are an integrated cover body, and around the axis along the document conveyance direction on the back side of the image reading apparatus 200 It is pivotally supported so that it can be opened and closed. When the upper cover body is opened, the document table glass 61 is opened, and a document can be placed on the document table glass 61. The document placed on the document table glass 61 is held by the cover body when the cover body is closed. When a document reading instruction is issued, the light source surface of the document on the document table glass 61 is exposed by the light source unit 210 while the light source unit 210 and the mirror unit 54 are moved in the sub-scanning direction. The reflected light from the document surface is guided to the imaging lens 55 by the light source unit 210 and the mirror unit 54, and is imaged on the CCD 56 by the imaging lens 55, where the document image is read. At this time, the light source unit 210 and the mirror unit 54 are moved while maintaining a predetermined speed relationship with each other, and the light path of the reflected light of the light irradiation surface of the document → the light source unit 210 and the mirror unit 54 → the imaging lens 55 → the CCD 56. Therefore, the positional relationship between the light source unit 210 and the mirror unit 54 is always maintained so that the length of the original image does not change, and thereby the focus of the original image on the CCD 56 is always maintained accurately.

  The entire original image read in this way is transmitted as image data to the apparatus main body A of the image forming apparatus D, and the image is recorded on the recording sheet in the apparatus main body A.

  On the other hand, the apparatus main body A of the image forming apparatus D includes an exposure apparatus 1, a developing apparatus 2 (2a, 2b, 2c, 2d), a photosensitive drum 3 (3a, 3b, 3c, 3d) acting as an image carrier, and charging. Intermediate transfer belt device 8 including a container 5 (5a, 5b, 5c, 5d), a cleaner device 4 (4a, 4b, 4c, 4d), and an intermediate transfer roller 6 (6a, 6b, 6c, 6d) acting as a transfer portion. A fixing device 12, a sheet conveying device 100, a paper feed tray 10 that functions as a paper feed unit, and a paper discharge tray 15 that functions as a paper discharge unit.

  The image data handled in the apparatus main body A of the image forming apparatus D is data corresponding to a color image using each color of black (K), cyan (C), magenta (M), yellow (Y), or a single color (for example, This corresponds to a monochrome image using (black). Accordingly, the developing device 2 (2a, 2b, 2c, 2d), the photosensitive drum 3 (3a, 3b, 3c, 3d), the charger 5 (5a, 5b, 5c, 5d), and the cleaner device 4 (4a, 4b, 4c, 4d) and four intermediate transfer rollers 6 (6a, 6b, 6c, 6d) are provided so as to form four types of images corresponding to the respective colors. Is associated with black, b with cyan, c with magenta, and d with yellow to form four image stations. Hereinafter, the description will be made with the suffixes a to d omitted.

  The photoconductor drum 3 is disposed at substantially the center in the vertical direction of the apparatus main body A. The charger 5 is a charging means for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential, and a charger type charger is used in addition to a contact type roller type or brush type charger. .

  Here, the exposure apparatus 1 is a laser scanning unit (LSU) provided with a laser diode and a reflection mirror, and exposes the surface of the charged photosensitive drum 3 according to image data, and according to the image data on the surface. An electrostatic latent image is formed.

  The developing device 2 develops the electrostatic latent image formed on the photosensitive drum 3 with (K, C, M, Y) toner. The cleaner device 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer.

  In addition to the intermediate transfer roller 6, the intermediate transfer belt device 8 disposed above the photosensitive drum 3 includes an intermediate transfer belt 7 that acts as an intermediate transfer member, an intermediate transfer belt drive roller 21, a driven roller 22, and a tension roller. 23, and an intermediate transfer belt cleaning device 9.

  Roller members such as the intermediate transfer belt drive roller 21, the intermediate transfer roller 6, the driven roller 22, and the tension roller 23 stretch and support the intermediate transfer belt 7, and the intermediate transfer belt 7 is supported in a predetermined conveyance direction (arrow in the figure). Move around in the C direction).

  The intermediate transfer roller 6 is rotatably supported inside the intermediate transfer belt 7 and is pressed against the photosensitive drum 3 via the intermediate transfer belt 7.

  The intermediate transfer belt 7 is provided so as to be in contact with each photoconductive drum 3, and a color toner image (each color is transferred by sequentially superimposing and transferring the toner image on the surface of each photoconductive drum 3 onto the intermediate transfer belt 7. Toner image). Here, the transfer belt 7 is formed in an endless belt shape using a film having a thickness of about 100 μm to 150 μm.

  The transfer of the toner image from the photosensitive drum 3 to the intermediate transfer belt 7 is performed by the intermediate transfer roller 6 that is in pressure contact with the inner side (back surface) of the intermediate transfer belt 7. A high voltage transfer bias (for example, a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 6 in order to transfer the toner image. Here, the intermediate transfer roller 6 is a roller based on a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). With this conductive elastic material, a high voltage can be uniformly applied to the recording sheet.

  The apparatus main body A of the image forming apparatus D further includes a secondary transfer apparatus 11 including a transfer roller 11a that functions as a transfer unit. The transfer roller 11a is in contact with the opposite side (outside) of the intermediate transfer belt 7 from the intermediate transfer belt drive roller 21.

  As described above, the toner images on the surfaces of the respective photosensitive drums 3 are stacked on the intermediate transfer belt 7 and become a color toner image indicated by the image data. The stacked toner images of the respective colors are transported together with the intermediate transfer belt 7 and transferred onto the recording sheet by the secondary transfer device 11.

  The intermediate transfer belt 7 and the transfer roller 11a of the secondary transfer device 11 are pressed against each other to form a nip region. The transfer roller 11a of the secondary transfer device 11 has a voltage (for example, a polarity (+) opposite to the toner charging polarity (-)) for transferring the toner image of each color on the intermediate transfer belt 7 to the recording sheet. Is applied). Further, in order to constantly obtain the nip region, either the transfer roller 11a of the secondary transfer device 11 or the intermediate transfer belt drive roller 21 is made of a hard material (metal or the like), and the other is a soft material such as an elastic roller. (Elastic rubber roller, foaming resin roller, etc.).

  In addition, the toner image on the intermediate transfer belt 7 may not be completely transferred onto the recording sheet by the secondary transfer device 11, and the toner may remain on the intermediate transfer belt 7. Causes color mixing. Therefore, the residual toner is removed and collected by the intermediate transfer belt cleaning device 9. The intermediate transfer belt cleaning device 9 includes, for example, a cleaning blade that contacts the intermediate transfer belt 7 as a cleaning member, and residual toner can be removed and collected by the cleaning blade. The driven roller 22 supports the intermediate transfer belt 7 from the inner side (back side), and the cleaning blade is in contact with the intermediate transfer belt 7 so as to press it toward the driven roller 22 from the outer side.

  The paper feed tray 10 is a tray for storing recording sheets, and is provided below the image forming unit of the apparatus main body A. A paper discharge tray 15 provided on the upper side of the image forming unit is a tray for placing printed recording sheets face down.

  In addition, the apparatus main body A is provided with a sheet conveying device 100 for sending the recording sheet in the paper feed tray 10 to the paper discharge tray 15 via the secondary transfer device 11 and the fixing device 12. The sheet conveying apparatus 100 has an S-shaped sheet conveying path S, and along the sheet conveying path S, a pickup roller 16, a sheet feeding roller 14a, a separation roller 14b, each conveying roller 13, and a pair of pre-registration rollers. 19, conveying members such as the registration roller pair 101, the fixing device 12, and the paper discharge roller 17 are disposed.

  The pickup roller 16 is a pull-in roller that is provided at the downstream end of the sheet feeding tray 10 in the sheet conveying direction and supplies recording sheets from the sheet feeding tray 10 to the sheet conveying path S one by one. The paper feed roller 14a passes the recording sheet between the separation roller 14b and conveys it to the sheet conveyance path S while separating the recording sheets one by one. Each conveyance roller 13 and the pre-registration roller pair 19 are small rollers for promoting and assisting conveyance of the recording sheet. Each conveying roller 13 is provided at a plurality of locations along the sheet conveying path S. The pre-registration roller pair 19 is provided in the immediate vicinity of the registration roller pair 101 on the upstream side in the sheet conveyance direction, and conveys the recording sheet to the registration roller pair 101.

  The fixing device 12 receives the recording sheet on which the toner image is transferred, and conveys the recording sheet by sandwiching the recording sheet between the heat roller 31 and the pressure roller 32.

  The temperature of the heat roller 31 is controlled so as to be a predetermined fixing temperature, and the recording sheet is thermocompression bonded together with the pressure roller 32 to melt, mix, and press the toner image transferred to the recording sheet. On the other hand, it has a function of heat fixing. The fixing device 12 is provided with an external heating belt 33 for heating the heat roller 31 from the outside.

  The recording sheet after fixing the toner images of the respective colors is discharged onto the paper discharge tray 15 by the paper discharge roller 17.

  It is also possible to form a monochrome image using at least one of the four image forming stations and transfer the monochrome image to the intermediate transfer belt 7 of the intermediate transfer belt device 8. Similarly to the color image, this monochrome image is also transferred from the intermediate transfer belt 7 to the recording sheet and fixed on the recording sheet.

  In addition, when performing image formation on both the front side and the front side of the recording sheet, the image on the surface of the recording sheet is fixed by the fixing device 12, and then the recording sheet is discharged on the sheet conveying path S in the sheet discharge roller 17. In the middle of the conveyance, the sheet discharge roller 17 is stopped and then reversely rotated, the recording sheet is passed through the front / back reversing path Sr, the recording sheet is reversed, and the recording sheet is again transferred to the registration roller pair 101. As in the case of the front surface of the recording sheet, the image is recorded and fixed on the back surface of the recording sheet, and the recording sheet is discharged to the paper discharge tray 15.

FIG. 2 is an exploded perspective view showing a schematic configuration of the light source unit 210 which is an example of the lighting apparatus according to the present embodiment. FIG. 3 is a diagram showing a schematic configuration of the light source 211 in the light source unit 210 shown in FIG. FIG. 3A shows a side view of the light source unit 210. FIG. 3B shows a side view of the light source 211. In FIG. 3 and FIG. 4 described later, the reading glass 52 or the document table glass 61 and the document G are also illustrated.

  The light source 211 provided in the light source unit 210 according to the present embodiment includes a plurality of light emitting elements (212a,...), (212b,...) Arranged in a predetermined row direction (here, the main scanning direction X). And substrates 213a and 213b for mounting the same. The plurality of light emitting elements (212a,...), (212b,...) Are all light emitting diode (LED) elements. The light axis L is the direction in which the luminous flux is the strongest among the light emitted from the light emitting elements (212a,...), (212b,...).

  The plurality of light emitting elements (212a,...), (212b,...) Irradiate light toward the light irradiation region (light irradiation position) L ′ of the document G, and the light irradiation surface G ′ of the document G. Are aligned in a line. This light irradiation area L ′ is set as a document surface reading position.

  In the present embodiment, as shown in FIG. 3, an orthogonal direction along the light irradiation surface G ′ of the document G that is orthogonal to the main scanning direction X with reference to the optical path R ′ of the reflected light from the document G (here, In this case, a plurality of light emitting elements (212a,...), (212b,...) Are arranged on the substrates 213a and 213b on both sides in the sub-scanning direction Y). That is, the plurality of light emitting elements (212a,...), (212b,...) Are arranged in a plurality of first rows arranged on one side of both sides in the sub-scanning direction Y with reference to the light irradiation region L ′. Are composed of one light emitting element 212a,... And a plurality of second light emitting elements 212b,. Here, the optical path R ′ of the reflected light is perpendicular to the light irradiation surface G ′ of the original G, and is positioned between the light emitting elements (212a,...), (212b,...) On both sides. ing.

  The substrates 213a and 213b are composed of first and second substrates 213a and 213b extending in the main scanning direction X and parallel to each other. .. Are mounted on the first substrate 213a, and a plurality of second light emitting elements 212b,... Are mounted on the second substrate 213b.

  In the present embodiment, the plurality of first light emitting elements 212a,... And the plurality of second light emitting elements 212b,... Are mounted on the substrate surface F of the first substrate 213a and the second substrate 213b, respectively. On the other hand, it has a light emitting surface E1 for performing side light emission for emitting light so that the optical axis L is parallel (see FIG. 3B). Specifically, the first substrate 213a on which the first light emitting elements 212a,... Are mounted and the second substrate 213b on which the second light emitting elements 212b,. It is arranged in a “C” shape with the side opposite to the original side opened so that the direction of L faces the light irradiation region L ′.

  As shown in FIG. 2, the light source unit 210 includes a light emitting element array unit 215 and a mirror base unit 216 on which the light emitting element array unit 215 is provided.

  The light emitting element array unit 215 includes a first light emitting element 212a, ..., a first substrate 213a on which the first light emitting elements 212a, ... are provided, a second light emitting element 212b, ..., and a second light emitting element 212b, ... And a base 214 on which the first substrate 213a and the second substrate 213b are provided.

  Specifically, the base 214 fixes the first and second substrates 213a and 213b with fixing members SC such as screws at both ends of the main scanning direction X with a predetermined interval. Thus, the first light emitting elements 212a,... And the second light emitting elements 212b,... Are arranged on both sides in the sub-scanning direction Y with respect to the optical path R ′ of the reflected light from the document G, respectively.

  The base 214 is further formed with a slit R extending along the main scanning direction X for allowing the reflected light from the document G to pass between the first substrate 213a and the second substrate 213b. The slit R is located immediately below the light irradiation region L ′ that is the document surface reading position.

  The mirror base unit 216 is provided with a first mirror 230. Specifically, the first mirror 230 guides the light reflected by the light irradiation surface G ′ of the original G to the second mirror 54 a of the mirror unit 54 through the slit R provided on the base 214. Are supported in a state of being inserted through an opening 216a along the main scanning direction X.

  FIG. 4 is a schematic side view showing another example of the light source 211 in the light source unit 210 shown in FIGS. 2 and 3.

  In the present embodiment, as shown in FIG. 4, a plurality of light emitting elements 212,... Are provided only on one side of both sides in the sub-scanning direction Y with reference to the optical path R ′ of the reflected light from the document G. It may be formed in a row on the substrate 213. Hereinafter, the light emitting element is simply referred to as an LED, the reference numerals 212a and 212b of the first and second light emitting elements are simply referred to as reference numeral 212, and the reference numerals 213a and 213b of the first and second substrates are simply referred to as reference numeral 213. .

  And the board | substrate 213 which mounted LED212, ... has a resist layer, and is making this resist layer white.

  FIG. 5 is a diagram for explaining a schematic configuration of the substrate 213 on which the LEDs 212,... Are mounted. 5A shows a longitudinal sectional view thereof, FIG. 5B shows a plan view thereof, and FIG. 5C shows a substrate angle in the state shown in FIG. 5B. The part is shown enlarged.

  As shown in FIG. 5A, the substrate 213 includes a base material 217, a conductive layer 218 formed thereon, and a resist layer 240 formed thereon. A typical example of the base material 217 is a paper phenol material. As the conductive layer 218, a copper foil pattern can be typically exemplified.

  According to the light source unit 210 described above, the white resist layer 240 has a higher light reflectivity than the conventional green resist layer, so that the illuminance on the light irradiation surface G ′ of the original G can be efficiently increased. be able to. In addition, efficiently improving the illuminance on the light irradiation surface G ′ of the original G also leads to a reduction in power consumption, and an energy saving design is possible.

  In the present embodiment, as shown in FIG. 5A, the substrate 213 is provided with a printing material 250 for white printing (here, white silk printing) on a white resist layer 240.

According to such a configuration, by using the white resist layer 240 as the base of the white silk printing material 250 applied to the substrate 213, it is possible to further improve the reflection efficiency, thereby further increasing the light of the original G. The illuminance can be increased on the irradiation surface G ′. That is, when white printing is performed on the green resist layer as in the past, the green color of the resist layer is transmitted through the white printed on the resist layer. It will not be white. In this regard, in the present embodiment, white printing can be performed to the original white color by performing white printing on the white resist layer 240. Further, when a conventional substrate provided with a green resist layer is used, if the thickness of the white silk printing material is thin, the color of the substrate surface becomes greenish. If multiple layers of white printing material are applied to make this white, it will be costly. In this regard, in the present embodiment, by using the white resist layer 240 as the base of the white silk printing material 250, the color of the substrate surface can be made good white without cost.

  In the present embodiment, the white resist layer 240 may be used as a base, and the silk printing on the substrate surface may be a color that matches the chromaticity characteristics of the LEDs 212. That is, instead of the white silk printing material 250, the light emission color on the light irradiation surface G ′ of the document G is changed to a predetermined (desired) light emission color according to the chromaticity characteristics of the light emission colors from the plurality of LEDs 212. A silk printing material 250 of such a color may be used.

  FIG. 6 is a diagram for explaining a usage example in which the color of the silk printing material 250 is changed in accordance with the chromaticity characteristics of the colors emitted from the LEDs 212. FIG. 6A is an XY chromaticity diagram showing chromaticity coordinates on a plane, and FIG. 6B is a diagram illustrating the color of a silk printing material.

  Here, in the LED 212 that individually emits light of R (red), G (green), and B (blue), the chromaticity characteristics of each LED vary, and the RGB light quantity is adjusted in order to produce a desired color. There is a need to. However, in the present embodiment, the illuminance is increased by making the resist layer 240 as a base white, and the original color of the LED 212 is not adjusted, and the color of the silk printing material 250 on the surface of the substrate is changed. By changing to one that matches the chromaticity characteristics, the light color from the LED 212 and the color of the silk printing material 250 can be combined to irradiate the light irradiation surface G ′ of the original G with the desired color.

  For example, as shown in FIG. 6, in the chromaticity coordinates of the light irradiated on the light irradiation surface G ′ of the original G, if the desired color is the blue region (see α region in the figure), the blue printing material is replaced with the red region (see FIG. 6). Light is applied to the original G by applying a red printing material in the case of the β region in the figure) or a green printing material in the case of the green region (see the γ region in the figure) with the resist layer 240 as a base by silk printing. The surface G ′ can be made closer to the target color of the light to be irradiated.

  In any case, when the resist layer 240 is used as the base and the silk printing material 250 is applied thereon, the resist layer 240 is white as the base, thereby improving the illuminance on the light irradiation surface G ′ of the document G. Can contribute.

  Next, a substrate on which the base resist layer color is green and silk-printed as in the prior art, and a base-resist layer 240 color is printed in white and silk-printed on the substrate 213 as in the present embodiment. The illuminance is measured on the light irradiation surface G ′ of the original G, and whether or not there is an effect of increasing the illuminance on the light irradiation surface G ′ of the original G will be described below.

  In addition, since it is difficult to manufacture silk printing to the substrate edge, in this embodiment, silk printing is applied to a predetermined distance d (about 0.3 mm in this case) as shown in FIG. 5C. I used what is. As the substrate, a base material such as paper phenol, each forming layer was made of a copper foil pattern, a resist layer, and a silk printing material, and these were formed in this order. That is, both substrates used a silk-coated material applied to the uppermost layer.

  The measurement of the illuminance on the light irradiation surface of the document is performed by applying the measurement surface of the illuminometer to the center position of the LED light source arranged in the main scanning direction X on the document surface reading position shown in FIG. It was done by lighting up. At that time, the image is read by the image reading apparatus 200 shown in FIG. 1 at the monochrome 50 sheet machine level, the printed matter printed by the apparatus main body A is visually confirmed, and the data image is image editing application software (Adobe Systems). (Photoshop (registered trademark) made by the company) level was corrected and confirmed, and the quality of the image was judged good.

  FIG. 7 shows a case where a substrate on which a white printing material is applied by silk printing under the condition that the color of the resist layer is green, and white, green, red, and red under the condition that the color of the resist layer is white. It is the figure which described the measurement result with the case where the board | substrate which apply | coated each blue printing material by silk printing was used.

  In this measurement result, “◯” is evaluated when “image quality is acceptable”, “Δ” is evaluated when “acceptable limit”, and “x” is evaluated when “not acceptable”.

  As can be seen from the results shown in FIG. 7, the illuminance on the light irradiation surface of the original is 1300 [lx (lux) on the substrate with the resist layer white rather than the substrate with the resist layer green. ] (2600 [lx] with white silk printing) was high, and the image quality was also excellently evaluated. That is, it was found that a better image can be obtained while improving the reflection efficiency.

  In the present embodiment, a white silk printing material 250 may be used as a base, and a diffusion layer 260 may be provided on the substrate surface. In other words, the substrate 213 may be provided with the white resist layer 240 as a base and the diffusion layer 260 as the uppermost layer.

  FIG. 8 is a cross-sectional view of another example of the substrate 213 shown in FIG. FIG. 8A shows an example in which a diffusion layer 260 is provided on a white resist layer 240. FIG. 8B shows a state where light is diffused by the diffusion layer 260. FIG. 9 is a graph showing the state of illuminance (bright spot) unevenness on the light irradiation surface G ′ of the original G with respect to the distance in the main scanning direction X. FIG. 9A shows a state of uneven illuminance when the diffusion layer 260 is not provided. FIG. 9B shows the state of uneven illuminance when the diffusion layer 260 is provided.

  When the light source 211 in which LEDs are arranged in an array is used, there is a possibility that unevenness and streaks are usually generated in the image due to the bright spots. In this regard, in the example shown in FIG. 8, the diffusion layer 260 is provided on the white resist layer 240. Alternatively, a white silk printing material 250 may be formed on the white resist layer 240, and a diffusion layer (here, a diffusion film layer) 260 may be further provided thereon.

  In such a configuration, as shown in FIG. 8 (b), light can be diffused in the diffusion layer 260, and both reflection and diffusion can be applied. As shown in FIG. 9 (a), diffusion is performed. Compared to the illuminance uneven state without the layer 260, as shown in FIG. 9B, the uneven density and streaks (bright spots) of the formed image are alleviated in the illuminance uneven state with the diffusion layer 260. Alternatively, it can be eliminated.

200 Image Reading Device 210 Illumination Device 211 Light Source 212 LED (Example of Light Emitting Element)
213 Substrate 240 White resist layer 250 White silk printing material 260 Diffusion layer D Image forming apparatus G Document R ′ Optical path of reflected light from document G

Claims (9)

In an illuminating device including a light source that irradiates light toward a document and that is formed by arranging a plurality of light emitting elements on a substrate,
The substrate has a resist layer;
The resist layer of the substrate is white, and further printed on the resist layer,
An illumination apparatus, wherein the white resist layer is used as a base, and the color of the printing is set to a color that matches the chromaticity characteristics of the colors emitted from the plurality of light emitting elements. The lighting device according to claim 1.
The lighting device according to claim 1, wherein the printing is silk printing. The lighting device according to claim 1 or 2,
The white resist layer as a base, lighting devices you characterized in that a diffusion layer. In the illuminating device as described in any one of Claim 1- Claim 3,
The illumination device according to claim 1, wherein the light emitted from the plurality of light emitting elements is side light emission having an optical axis parallel to a substrate surface of the substrate. In the illuminating device as described in any one of Claim 1- Claim 4,
An illuminating apparatus comprising: a plurality of light emitting elements arranged in a row only on one side with reference to an optical path of reflected light from a document. In the illuminating device as described in any one of Claim 1- Claim 4,
An illuminating device comprising a plurality of light emitting elements arranged on both sides with respect to an optical path of reflected light from a document. In the illuminating device as described in any one of Claim 1- Claim 6,
The light emitting element is a light emitting diode element.   An image reading apparatus comprising the illumination device according to claim 1.   An image forming apparatus comprising the image reading apparatus according to claim 8.

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