JP2015072294A - Illumination device, electricity removing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce unevenness in the light intensity in an arrangement direction of a plurality of light-emitting elements with a simple configuration in an illumination optical system having the light-emitting elements arranged on a substrate.SOLUTION: A plurality of LED chips 61 are arranged on a substrate 60, and light buffering parts 62 are arranged respectively on the front side in the light irradiation direction (optical axis) 61a of the respective LED chips 61. The LED chips 61 each have the light irradiation direction 61a inclined with respect to the arrangement direction of the substrate 60.

Description

  The present invention relates to an illuminating device in which a plurality of light emitting elements are arranged on a substrate, a neutralizing device including the illuminating device, and an image forming apparatus including the neutralizing device.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, a static eliminator is disposed around a photosensitive drum in order to remove charges on the surface of the photosensitive drum (electrostatic latent image carrier).

  FIG. 12 shows a configuration example of a conventional static eliminator together with a photosensitive drum.

  The static eliminator 100 includes a substrate 103 on which a plurality of light emitting elements (LED chips) 102 as light sources for irradiating the photosensitive drum 101 are mounted.

  The substrate 103 is formed in a long plate-like body so as to be arranged in parallel along the outer peripheral surface of the cylindrical photosensitive drum 101, and on one surface (main surface) 103a of the substrate 103, The LED chips 102 are arranged (mounted) in a line at a predetermined interval along the longitudinal direction X. These LED chips 102 have a light irradiation direction (hereinafter also referred to as “optical axis”) 102 a orthogonal to the longitudinal direction (arrangement direction) X of the LED chips 102 (that is, the optical axis of the LED chip 102). 102 a is arranged so as to be perpendicular to the light irradiation surface 101 a which is the outer peripheral surface of the photosensitive drum 101. The light irradiation direction is configured to be parallel to the main surface 103 a of the substrate 103. That is, the LED chip 102 shown in FIG. 12 is a side-emitting LED chip. The optical axis is a virtual light beam that is representative of the light beam emitted from the optical system, and coincides with the direction of the peak component of the light beam of the irradiated light.

  In the static eliminator 100 having such a configuration, the light quantity unevenness in the arrangement direction X of the light irradiated on the light irradiation surface 101a of the photosensitive drum 101 is flattened by increasing the arrangement interval of the LED chips 102. Can do. However, since the number of LED chips used increases, there is a problem that it is difficult to reduce the price.

  Therefore, the LED chips 102 are arranged at a predetermined interval in order to reduce the price. Here, the predetermined interval takes into consideration the directivity and light distribution angle of the LED chip 102, and the light spread (irradiation) when the irradiation light from the LED chip 102 reaches the light irradiation surface 101a of the photosensitive drum 101. The area) is an interval that slightly overlaps between adjacent LED chips.

  In this case, when light is irradiated onto the light irradiation surface 101a of the photosensitive drum 101 from each LED chip 102 arranged at a predetermined interval, the irradiation surface 101a of the photosensitive drum 101 facing the optical axis 102a of each LED chip 102 is irradiated. There is a problem in that the amount of light at the optical axis 102a increases, and the amount of light between the optical axes 102a (the amount of light at the overlapping portion of the irradiation area) inevitably decreases, causing unevenness in the amount of light.

  Therefore, as means for solving such a problem, Patent Document 1 discloses that a light diffusion lens is disposed in front of an LED chip that is a light emitter, and light is applied to the light irradiation surface of the photosensitive drum via the light diffusion lens. A configuration for reducing unevenness in the amount of light in the arrangement direction by irradiation is described.

  However, in this case, a new component member called a light diffusing lens is required, which makes it difficult to reduce the price and also complicates the apparatus, which makes it difficult to reduce the size structurally. .

  On the other hand, although it is not a static eliminator, Patent Documents 2 and 3 disclose that, as an illumination optical system, a plurality of LED chips are arranged in parallel with respect to the light irradiation surface of an irradiation object, and the optical axis of each LED chip is set. A configuration is described in which it is inclined with respect to the light irradiation surface.

  According to this configuration, by tilting the LED chip, the distance until the optical axis of the LED chip reaches the light irradiation surface is lengthened, and the irradiation region to the light irradiation surface is expanded along the inclination direction. Unevenness in the amount of light can be reduced.

JP 2013-171274 A JP 2012-142847 A JP 2011-23968 A

  Accordingly, the inventors inclined the LED chip with respect to the arrangement direction X from the illumination optical system having the arrangement configuration shown in FIG. 12 and the arrangement configuration shown in FIG. 12 (30 degrees in this example). An illumination optical system (see FIG. 13) was prepared, and the change in the amount of light in the arrangement direction X was measured. The measurement results are shown in FIG.

  As shown in FIG. 14, when the optical axis of the LED chip is irradiated perpendicularly to the light irradiation surface of the photosensitive drum (in the case of FIG. 12), as shown by a thin line graph in FIG. Regarding the change in the amount of light in the direction, the maximum value is about 60 μW and the minimum value is about 20 μW. The maximum amount of light unevenness is 40 μW, and the amount of light unevenness with a large vertical fluctuation is also generated between adjacent LED chips. On the other hand, when the LED chip is tilted at a predetermined angle (in the case of FIG. 13), as shown by a thick line graph in FIG. 14, the maximum change is about 50 μW and the minimum value is about 20 μW. Thus, the unevenness in the amount of light is improved by about 30 μW and 10 μW at the maximum. It can also be seen that the vertical fluctuation range between adjacent LED chips is improved as compared with the case of FIG.

  However, even in the arrangement shown in FIG. 13, the light amount unevenness is still 30 μW, and it cannot be said that the fluctuation range between the upper and lower LED chips is sufficiently improved (flattened).

  Accordingly, when the light irradiation surface of the photosensitive drum is neutralized by a static eliminator using such an illumination optical system, the residual potential after neutralization becomes non-uniform and affects the subsequent charging potential. . Further, since the charged potential becomes non-uniform, there arises a problem that even if the document has a uniform image density, image unevenness may occur during printing.

  The present invention was devised to solve such problems, and an object thereof is to reduce unevenness in the amount of light in the arrangement direction of light emitting elements with a simple structure in an illumination optical system in which a plurality of light emitting elements are arranged on a substrate. An object of the present invention is to provide an illuminating device that can be reduced, a static eliminator including the illuminator, and an image forming apparatus including the static eliminator.

  In order to solve the above-described problem, the illumination device of the present invention is characterized in that a plurality of light emitting elements are arranged on a substrate, and a light buffering portion is arranged on the front side in the light irradiation direction of each light emitting element. Yes. That is, the light reaching the light buffering portion from the light emitting element is not completely blocked, but partially transmitted, thereby reducing the light transmitted through the portion and flattening the light amount unevenness as a whole. It is configured.

  Moreover, in the illuminating device of this invention, the said light emitting element is set as the structure by which the light irradiation direction inclined with respect to the arrangement direction of the said board | substrate. According to this configuration, the optical axis is inclined with respect to the direction orthogonal to the arrangement direction, and as a result, the irradiation region of the light reaching the substrate edge on the front side in the light irradiation direction is expanded.

  Moreover, in the illuminating device of this invention, the said light buffer part is a translucent member which permeate | transmits light. By forming the light buffer portion with a translucent member, light transmitted through the light buffer portion is reduced.

  In the illumination device of the present invention, the plurality of light emitting elements and the plurality of light buffering portions are arranged in parallel. That is, the distance between each light emitting element and each light buffering portion facing this is made equal.

  Further, in the illumination device of the present invention, the light emitting element and the light buffering unit are arranged in parallel in the arrangement direction with respect to the light irradiation surface of the irradiation object, and a part of the irradiation light from the light emitting element is: It can be set as the structure which permeate | transmits the said light buffer part and is irradiated to the said light irradiation surface. That is, the light amount is gently reduced instead of completely blocking light.

  Moreover, in the illuminating device of this invention, the said light buffer part is set as the structure provided in the shortest distance position between the said light emitting element and the said light irradiation surface of the said irradiation target object. That is, the light amount of the irradiation region with the largest amount of light is reduced on the light irradiation surface of the irradiation object.

  In the illumination device of the present invention, the light buffering portion is arranged on the substrate, and the light irradiation direction of the light emitting element is parallel to the mounting surface of the substrate on which the light emitting element is mounted. That is, the lighting device is a side light emitting type lighting device.

  Further, the static eliminator of the present invention has a configuration in which the illumination devices having the above-described configurations are arranged in parallel to the light irradiation surface of the electrostatic latent image carrier that is the irradiation object. According to this configuration, it is possible to flatten unevenness in the amount of light irradiated on the light irradiation surface of the electrostatic latent image carrier and to uniformize the amount of charge removal.

  Further, the image forming apparatus of the present invention is configured to include the static eliminator configured as described above. According to this configuration, unevenness in the amount of light applied to the light irradiation surface of the electrostatic latent image carrier can be flattened and the amount of charge removed can be made uniform, so that the print quality is improved.

  In the image forming apparatus according to the aspect of the invention, the static eliminator may be one of the substrates on which the light emitting elements are arranged with respect to the charging device disposed around the light irradiation surface of the electrostatic latent image carrier. It is set as the structure arrange | positioned so that a surface may be located on the opposite side to the said charging device. That is, the arrangement configuration is such that irradiation light from the static eliminator does not enter the charging device side.

  According to the illuminating device of the present invention, by transmitting the light that reaches the light buffering portion of the light emitted from the light emitting element, the amount of the light that passes through the portion can be reduced. Therefore, the light amount unevenness as a whole can be flattened by disposing the light buffer portion at a position corresponding to the irradiation region where the light amount increases to reduce the light amount.

  In addition, according to the static eliminator of the present invention, it is possible to flatten unevenness in the amount of light applied to the light irradiation surface of the electrostatic latent image carrier, and make the amount of static elimination uniform.

  In addition, according to the image forming apparatus of the present invention, the unevenness of the amount of light irradiated on the light irradiation surface of the electrostatic latent image carrier is flattened to make the amount of charge neutralized uniform, thereby affecting the subsequent charging potential. Never give. Therefore, the print quality can be improved.

It is the schematic sectional drawing which looked at the image forming apparatus carrying the static elimination apparatus using the illuminating device which concerns on this invention from the front. 2 is an enlarged cross-sectional view of one image forming station of the image forming unit. FIG. It is the schematic perspective view which showed typically the static elimination apparatus using the illuminating device which concerns on Embodiment 1. FIG. It is a top view which shows the arrangement | positioning relationship between a photoconductor drum and a static elimination apparatus. It is a graph which shows the result of having changed the width | variety of the light buffer part variously and measuring the light quantity change in a light irradiation surface. It is a graph which shows the result of having changed the thickness of the light buffer part variously and measuring the light quantity change in a light irradiation surface. FIG. 5 is a graph showing a change in the amount of light on the light irradiation surface of the photosensitive drum using the static eliminator according to the first embodiment. FIG. 6 is a plan view showing a positional relationship between a static eliminator using the illumination device according to Embodiment 2 and a photosensitive drum. FIG. 10 is a graph showing a change in the amount of light on the light irradiation surface of the photosensitive drum using the static eliminator according to the second embodiment. FIG. 6 is a plan view showing a positional relationship between a static eliminator using an illumination device according to Embodiment 3 and a photosensitive drum. FIG. 6 is a graph showing a change in the amount of light on the light irradiation surface of a photosensitive drum using the static eliminator according to Embodiment 3. It is a top view which shows the example of 1 structure of the conventional static elimination apparatus. It is a top view which shows the other structural example of the conventional static elimination apparatus. FIG. 14 is a graph showing the illumination optical system having the arrangement configuration shown in FIG. 12 and the illumination optical system having the arrangement configuration shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

-Description of overall configuration of image forming apparatus-
FIG. 1 is a schematic cross-sectional view of an image forming apparatus equipped with a static eliminator using an illumination device according to the present invention as seen from the front.

  An image forming apparatus 1 shown in FIG. 1 is a multifunction machine having a copying function, a facsimile function, a printer function, a scanner function, and the like. The image forming apparatus 1 has an image forming unit 10 and an image reading unit 20 having a document image reading unit 20. This is a cylinder discharge type image forming apparatus in which a cylinder discharge space portion 50 having a U-shaped cross section is formed between the body and the body.

  The inner bottom surface 50a of the in-body discharge space 50 is a discharge tray 17, and a discharge roller 36, which will be described later, is disposed on the inner back surface 50b.

  A document feeder (ADF) 40 is provided on the upper part of the image reading unit 20, and this document feeder 40 rotates a hinge (not shown) provided at an edge on the back side of the upper surface of the image reading unit 20. The front side is provided as a moving center so that it can be opened and closed in the vertical direction (that is, it can be opened and closed with respect to the image reading unit 20).

  In the image forming apparatus 1 having such a configuration, a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (for example, black). The image data corresponding to is handled. For this reason, the image forming unit 10 is provided with four developing devices 12, photoconductor drums 13, cleaning devices 14, charging devices 15 and neutralizing devices 16 for forming four types of toner images, each of which is black. , Cyan, magenta, and yellow are associated with four image stations Pa, Pb, Pc, and Pd.

  FIG. 2 is an enlarged sectional view showing one image forming station of the image forming unit 10. As shown in FIG. 2, in any of the image stations Pa, Pb, Pc, and Pd, a drum cleaning device 14, a charge eliminating device 16, a charging device 15, and a developing device 12 are disposed around the photosensitive drum 13. As the photosensitive drum 13 rotates, processing by the devices 14, 16, 15, and 12 is sequentially performed. The drum cleaning device 14 removes and collects residual toner on the surface of the photosensitive drum 13. The static eliminator 16 removes the charge on the surface of the photosensitive drum 13. The charging device 15 uniformly charges the surface of the photosensitive drum 13 to a predetermined potential. Thereafter, an electrostatic latent image is formed on the surface of the photosensitive drum 13 by the optical scanning device 11 (see FIG. 1). The optical scanning device 11 is a laser scanning unit (LSU) provided with a laser diode and a reflection mirror, and exposes the surface of each charged photosensitive drum 13 according to image data and corresponds to the image data on those surfaces. An electrostatic latent image is formed. The developing device 12 develops the electrostatic latent image on the surface of the photosensitive drum 13 to form a toner image on the surface of the photosensitive drum 13. As a result, toner images of the respective colors are formed on the surface of the photosensitive drum 13 of each image station Pa, Pb, Pc, Pd.

  An intermediate transfer belt 19 is disposed on the upper side of the photosensitive drum 13. The intermediate transfer belt 19 circulates in the direction of arrow C, the residual toner is removed and collected by the belt cleaning device 25, and the toner images of the respective colors formed on the surfaces of the photosensitive drums 13 are sequentially transferred and superimposed. Thus, a color toner image is formed on the surface of the intermediate transfer belt 19.

  Returning to FIG. 1, a nip is formed between the transfer roller 26a of the secondary transfer device 26 and the intermediate transfer belt 19, and the sheet conveyed through the sheet conveyance path R1 is sandwiched and conveyed. . When the sheet passes through the nip, the toner image on the surface of the intermediate transfer belt 19 is transferred and conveyed to the fixing device 30.

  The fixing device 30 sandwiches the sheet with the toner image transferred between the fixing roller 31 and the pressure roller 32 and heats and presses the sheet to fix the toner image on the sheet.

  The paper feed cassette 55 is provided below the optical scanning device 11. The paper is pulled out from the paper feed cassette 55 by the pickup roller 56a and the suction roller 56b, and is transported to the paper transport path R1. The paper discharge roller provided in the paper discharge unit 38 via the secondary transfer device 26 and the fixing device 30. It is carried out to the paper discharge tray 17 via 36. A registration roller 34, a conveyance roller 35, and a paper discharge roller 36 are arranged in the paper conveyance path R1.

  When image formation is performed on the back side, the paper is conveyed in the reverse direction from the paper discharge roller 36 to the reverse conveyance path Rr, the front and back sides of the paper are reversed, the paper is guided again to the registration roller 34, and the front surface Similarly, image formation is performed on the back surface, and the paper is carried out to the paper discharge tray 17.

-Description of Document Feeder 40-
The document feeder 40 includes a document tray 41 on which the document M is placed, a discharge tray 42 on which the document M is discharged, and a first transport in which the document M placed on the document tray 41 is transported to the reading position P1. A path 43a, a second transport path 43b in which the document M transported to the reading position P1 is transported to the discharge tray 42, and a reverse transport path 43c in which the document M that has passed the reading position P1 is returned to the first transport path 43a. Including. The reading position P1 is a position where light is emitted from the light source 23a through the document reading glass 22 described later.

  A pickup roller 44 is provided in the vicinity of the document tray 41, and a suction roller 45 is provided in the vicinity of the pickup roller 44.

  The first conveyance path 43a is provided with a conveyance roller pair 46a and a conveyance roller pair 46b, and the second conveyance path 43b is provided with a conveyance roller pair 46c, a conveyance roller pair 47, and a discharge roller pair 48. .

  The transport roller pair 47 and the discharge roller pair 48 are disposed between the junction P3 and the discharge tray 42. Further, the discharge roller pair 48 is provided in a document discharge portion (paper discharge portion) 43b1 of the second transport path 43b.

  The conveyance roller pair 47 includes a driving roller 47a and a driven roller 47b. The discharge roller pair 48 includes a driving roller 48a and a driven roller 48b.

  A claw member 49 is provided in the vicinity of the junction P3. The claw member 49 is configured to open the second transport path 43b by being pushed up by the document M when the document M is transported in the transport direction (paper transport direction) Z.

-Description of Image Reading Unit 20-
The image reading unit 20 includes a document table glass 21, a document reading glass 22, a light source unit 23, a mirror unit 24, and an imaging unit 25.

  The light source unit 23 includes a light source 23 a that irradiates light toward the document M, and a mirror 23 b that guides reflected light from the document M to the mirror unit 24. The mirror unit 24 includes a mirror 24a and a mirror 24b. The imaging unit 25 includes a condenser lens, a CCD (Charge Coupled Device), and the like.

  Although details are omitted, the image reading unit 20 is configured to be able to perform reading by the document fixing method and reading by the document moving method.

  The above is the description of the overall configuration of the image forming apparatus 1.

  Next, an embodiment of a static eliminator using the illumination device according to the present invention will be described.

<Embodiment 1>
FIG. 3 is a schematic perspective view schematically showing a static eliminator using the illumination device according to the first embodiment, and FIG. 4 is a plan view showing a positional relationship between the photosensitive drum and the static eliminator.

  In the static eliminator 16 </ b> A according to the first embodiment, a plurality of LED chips (light emitting elements) 61 are arranged on the substrate 60, and the light buffering portions 62 are respectively provided on the front side of the light irradiation direction (optical axis 61 a) of each light emitting element 61. It has an arranged configuration.

  The light buffer 62 is formed of a translucent member, and can be formed using, for example, polyethylene terephthalate (PET) resin. However, it may be semi-transparent and is not limited to PET.

  According to this configuration, the light reaching the light buffer unit 62 from the LED chip 61 is not completely blocked, but partially transmitted, thereby reducing the amount of light transmitted through the portion. . Further, by making it translucent, the amount of light can be gradually reduced as compared with the case where light is completely blocked.

  The substrate 60 is arranged along the light irradiation surface 13a that is the outer peripheral surface of the cylindrical photosensitive drum 13 in parallel with the scanning direction of the light irradiation surface 13a (that is, the rotation axis direction of the photosensitive drum 13). Long side (same as the scanning direction of the light irradiation surface 13a) X on one side edge 60a1 of one surface (main surface) 60a of the substrate 60 X LED chips 61 are arranged (mounted) in a row at a predetermined interval P.

  Further, on the other side edge portion 60a2 of the main surface 60a of the substrate 60, the light buffer portions 62 are arranged (arranged) in a row at a predetermined interval P along the longitudinal direction X.

  Therefore, the plurality of LED chips 61 and the plurality of light buffering portions 62 are arranged in parallel on the main surface (mounting surface) 60a of the substrate 60, and each LED chip 61 and each of the light buffering portions 62 facing the LED chip 61 are arranged. (The distance from the light emitting point a of the LED chip 61 (see FIG. 4) to the opposing surface of the light buffering portion 62) T is all equal. That is, the LED chip 61 and the light buffer 62 are arranged along the light irradiation surface 13a of the photosensitive drum 13 in parallel with the scanning direction of the light irradiation surface 13a.

  The light irradiation direction (optical axis 61a) of the LED chip 61 is parallel to the main surface (mounting surface) 60a of the substrate 60. That is, the LED chip 61 of Embodiment 1 is a side light emission type LED chip.

  In the above configuration, in the first embodiment, each LED chip 61 is provided such that the light irradiation direction (optical axis 61 a) is inclined with respect to the arrangement direction X on the substrate 60 by a predetermined angle θ.

  According to this configuration, the optical axis 61 a is inclined by the predetermined angle θ with respect to the direction Y orthogonal to the arrangement direction X, and as a result, the irradiation region of the light reaching the light irradiation surface 13 a of the photosensitive drum 13. Can be expanded in the scanning direction X. In addition, as in the prior art, by tilting the LED chip 61, it is possible to reduce unevenness in the amount of light with respect to the scanning direction X of the light irradiation surface 13a compared to when the LED chip 61 is not tilted. The first embodiment is characterized in that, in such a configuration, the light buffer 62 is disposed on the front side of the light irradiation direction (optical axis 61a) of the LED chip 61.

  The light buffer 62 is provided at the shortest distance between the LED chip 61 and the light irradiation surface 13 a of the photosensitive drum 13.

  According to this configuration, the amount of light in the irradiation region with the largest amount of light can be reduced on the light irradiation surface 13 a of the photosensitive drum 13, so that unevenness in the amount of light as the entire irradiation region can be flattened in the arrangement direction of the LED chips 61. it can.

  Further, as shown in FIG. 1, the static eliminator 16 </ b> A according to the first embodiment is different from the charging device 15 arranged around the light irradiation surface 13 a of the photosensitive drum 13 in that the main surface 60 a of the substrate 60 is the same as the charging device 15. Are arranged on the opposite side (that is, on the upstream side in the moving direction C of the photosensitive drum 13).

  According to this configuration, it is possible to configure so that the irradiation light from the static eliminator 16A does not enter the charging device 15 side.

  Here, the present inventors made prototypes of various dimensions with respect to the width and thickness of the light buffer portion 62 and conducted experiments on the light amount unevenness.

  First, an experiment was performed on the width of the light buffer 62.

  In this experiment, the arrangement interval P of each LED chip 61 is 27 mm, the distance T between the LED chip 61 and the light buffering portion 62 facing the LED chip 61 is 4.5 mm, and the inclination angle θ of the LED chip 61 is 30 degrees. Set. Further, regarding the positional relationship between the light buffer 62 and the LED chip 61 in the direction Y orthogonal to the light irradiation surface 13 a of the photosensitive drum 13, the light from the light emitting point a of the LED chip 61 to the light of the photosensitive drum 13. The center in the width direction of the light buffering section 62 facing the line extending perpendicularly to the irradiation surface 13a is shifted by 0.5 mm in the tilt direction of the LED chip 61 (leftward in FIG. 4).

  Under these setting conditions, the change in the amount of light on the light irradiation surface 13a was measured by changing the width of the light buffer 62 in various ways. The measurement results are shown in FIG.

  In FIG. 5, five types of light buffer portions 62 having a width of 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm are manufactured, and the light buffer portion 62 is not disposed thereon (the structure shown in FIG. 13 and the inclination angle). The change in the amount of light was measured for all six types. In addition, about the dimension of the depth direction (light transmission direction) of the light buffer part 62, it was 2.5 mm about the light buffer part 62 of all kinds.

  As a result, as is apparent from FIG. 5, the change in the amount of light in the arrangement direction of the conventional structure (graph indicated by reference numeral 70) has a maximum value of about 50 μW, a minimum value of about 36 μW, and a light amount unevenness of up to 14 μW. Occurrence of the light amount unevenness having a large fluctuation range between the adjacent LED chips is generated.

  On the other hand, the change in the amount of light in the arrangement direction of the optical buffer 62 having a width of 2 mm (graph indicated by reference numeral 71) has a maximum value of approximately 45 μW and a minimum value of approximately 34 μW, and unevenness in the amount of light of 11 μW at maximum occurs. Even between adjacent LED chips, unevenness in the amount of light with a relatively large fluctuation range is generated.

  In addition, the light quantity change in the direction of arrangement of the light buffer sections 62 having a width of 3 mm (graph indicated by reference numeral 72) has a maximum value of approximately 40 μW and a minimum value of approximately 34 μW, and remains at a maximum unevenness of 6 μW. Even between LED chips, the amount of fluctuation in the vertical direction is relatively small.

  In addition, the light amount change (graph indicated by reference numeral 73) in the arrangement direction of the light buffer portions 62 having a width of 4 mm has a maximum value of approximately 39 μW and a minimum value of approximately 33 μW, and the maximum amount of light unevenness is 6 μW. Even between LED chips, the amount of fluctuation in the vertical direction is relatively small.

  The light amount change (graph indicated by reference numeral 74) in the arrangement direction of the light buffer portions 62 having a width of 5 mm has a maximum value of about 40 μW and a minimum value of about 31 μW. Even between the LED chips, the fluctuation range in the vertical direction is slightly larger than that of the light buffer 62 having a thickness of 3 mm or 4 mm.

  In addition, the change in the amount of light in the arrangement direction of the light buffer sections 62 having a width of 6 mm (graph indicated by reference numeral 75) has a maximum value of approximately 40 μW and a minimum value of approximately 31 μW, and remains at a maximum unevenness of 9 μW. Even between the LED chips, the fluctuation range in the vertical direction is slightly larger than that of the light buffer 62 having a thickness of 3 mm or 4 mm.

  As a result of the above experiment, it can be seen that a width of 3 mm to 4 mm as the width of the light buffer portion 62 is suitable for improving the light amount unevenness.

  Next, an experiment was conducted on the thickness of the light buffer 62.

  In other words, under the same setting conditions as described above, the light amount change on the light irradiation surface 13a was measured by changing the thickness of the light buffer 62 in various ways. However, here, the width of the light buffer 62 is set to 3 mm from the above examination result. The measurement results are shown in FIG.

  In FIG. 6, four types of light buffer portions 62 having thicknesses t of 0.3 mm, 0.4 mm, 0.5 mm, and 0.6 mm are manufactured, and a conventional structure in which the light buffer portion 62 is not disposed thereon (FIG. 13). The change in the amount of light was measured for all five types, including the structure shown in FIG. Here, the thickness t of the light buffer portion 62 is set to a thickness including the thickness of the adhesive for bonding the light buffer portion 62 onto the main surface 60 a of the substrate 60. In this experiment, a double-sided tape is used as the adhesive, and its thickness is 0.12 mm. Therefore, the actual thickness of the optical buffer 62 itself is four types of 0.18 mm, 0.28 mm, 0.38 mm, and 0.48 mm obtained by subtracting 0.12 mm corresponding to the thickness of the tape.

  As a result, as is apparent from FIG. 6, the change in the amount of light in the arrangement direction of the optical buffer 62 having a thickness t of 0.3 mm (graph indicated by reference numeral 81) has a maximum value of approximately 45 μW and a minimum value of approximately 34 μW. A maximum of 11 μW of light amount unevenness occurs, and a light amount unevenness with a relatively large fluctuation width between adjacent LED chips is also generated.

  Further, the change in the amount of light in the arrangement direction of the optical buffer 62 having a thickness t of 0.4 mm (graph indicated by reference numeral 82) has a maximum value of about 40 μW and a minimum value of about 35 μW, and the light amount unevenness of 5 μW at the maximum remains. Even in the adjacent LED chips, the vertical fluctuation width is smaller than that of the light buffer 62 having a thickness of 0.3 mm.

  The light amount change (graph indicated by reference numeral 83) in the arrangement direction of the light buffer portions 62 having a thickness t of 0.5 mm has a maximum value of approximately 39 μW, a minimum value of approximately 31 μW, and a maximum light amount unevenness of 8 μW. Even between adjacent LED chips, the vertical fluctuation width is slightly larger than that of the 0.4 mm light buffer 62. Further, in the light buffer 62 having a thickness t of 0.5 mm, the overall light amount level is lower than that of the light buffer 62 having a thickness of 0.4 mm.

  The light amount change (graph indicated by reference numeral 84) in the arrangement direction of the optical buffer 62 having a thickness t of 0.6 mm has a maximum value of about 35 μW, a minimum value of about 25 μW, and a maximum amount of light unevenness of 10 μW. Even between adjacent LED chips, the fluctuation range in the vertical direction is larger than that of the light buffer 62 having a thickness of 0.5 mm. Moreover, in the optical buffer part 62 with the thickness t of 0.6 mm, the entire light quantity level is further reduced compared to the optical buffer part 62 with a thickness of 0.5 mm.

  As a result of the above experiment, it is understood that the thickness t (including the thickness of the adhesive) t of the light buffering portion 62 is preferably 0.4 mm that can maintain the entire light amount level and has small light amount unevenness. However, as can be seen from the above experimental results, the thickness t of the light buffer portion 62 does not have to be strictly 0.4 mm, and if the thickness is between 0.35 and 0.45 mm, the unevenness in the amount of light is sufficient. Inferred to be improved.

  Next, the present inventors made a light buffer 62 having a width of 3 mm and a thickness of 0.4 mm based on the above experimental results, and made a static eliminator (illuminating device) 16A equipped with this (this is referred to as document 1). ). Then, the manufactured static eliminator 16A is arranged in parallel along the light irradiation surface 13a of the photosensitive drum 13, and the light irradiation surface 13a is actually irradiated with light to scan the light irradiation surface 13a (LED chip 61). The light amount unevenness along the arrangement direction X) was measured. The measurement results are shown in FIG.

  In FIG. 7, for comparison, in addition to the material 1, the light amount unevenness was also measured for the conventional structure shown in FIG. 13 (this material is referred to as the material 2). In addition, the LED chip 61 is also measured for each of two types of cases where the illuminance is maximized (Document 1-1, Document 2-1) and when the illuminance is minimized (Document 1-2, Document 2-2). went.

  As a result, as is clear from FIG. 7, when the data 1-1 and the data 2-1 when the illuminance is maximized are compared, in the data 2-1, the light amount change in the arrangement direction is almost the maximum value. 60 μW, the minimum value is about 35 μW, and a maximum of 25 μW of light intensity unevenness occurs, and light intensity unevenness with a large vertical fluctuation width also occurs between adjacent LED chips. On the other hand, in the document 1-1, the change in the amount of light in the arrangement direction has a maximum value of about 49 μW and a minimum value of about 35 μW, and the maximum light amount unevenness of 14 μW remains. In addition, the vertical fluctuation range between adjacent LED chips is significantly improved compared to that of the document 2-1, and it is understood that the light amount level is flattened (uniformized) as a whole.

  Further, when comparing the document 1-2 and the document 2-2 when the illuminance is minimized, in the document 2-2, the light amount change in the arrangement direction is approximately 37 μW at the maximum value and approximately 23 μW at the minimum value. A maximum of 14 μW of light amount unevenness occurs, and a light amount unevenness with a relatively large fluctuation width between the adjacent LED chips occurs. On the other hand, in Document 1-2, the change in the amount of light in the arrangement direction has a maximum value of approximately 31 μW and a minimum value of approximately 19 μW. In addition, the vertical fluctuation range between adjacent LED chips is greatly improved as compared with that of Document 2-2, and it is understood that the light amount level is flattened (uniformized) as a whole.

<Embodiment 2>
FIG. 8 is a plan view showing a positional relationship between a static eliminator using the illumination device according to the second embodiment and a photosensitive drum.

  In the static eliminator 16B according to the second embodiment, a plurality of LED chips 61 are arranged at a predetermined angle θ along the other side edge 60a2 of the substrate 60, and the light irradiation direction (optical axis 61a) of each light emitting element 61 is arranged. The light reflecting plate 63 is disposed along one side edge 60a1 of the substrate 60 which is the front side of the substrate 60).

  That is, in the static eliminator 16A of the first embodiment, the LED chip 61 is disposed on one side edge 60a1 of the substrate 60 far from the photosensitive drum 13, whereas in the second embodiment, the LED chip 61 is a photosensitive member. It is disposed on the other side edge 60 a 2 of the substrate 60 close to the drum 13, and the light irradiation direction is disposed on the opposite side to the light irradiation surface 13 a of the photosensitive drum 13. Therefore, in the second embodiment, a light reflecting plate 63 that is not in the first embodiment is added. On the other hand, the light buffer 62 arranged in the first embodiment is not arranged in the second embodiment, but as can be seen from the drawing, in the second embodiment, the LED chip 61 itself is reflected by the light reflecting plate 63. It acts as a light buffer that reduces the amount of light in part. Here, in the second embodiment, the predetermined angle is set to 20 degrees.

  The present inventors produced a static eliminator (illumination device) 16B according to Embodiment 2 (this is referred to as Document 4). Then, the manufactured static eliminator 16B is arranged in parallel along the light irradiation surface 13a of the photosensitive drum 13, and the light irradiation surface 13a is actually irradiated with light to scan the light irradiation surface 13a (LED chip 61). The light amount unevenness along the arrangement direction X) was measured. The measurement results are shown in FIG.

  In FIG. 9, for comparison, the light amount unevenness is also measured for the conventional structure shown in FIG. 13 (this is referred to as “Document 3”), and the measurement results are also shown.

  As a result, as can be seen from FIG. 9, in document 3, the light quantity change in the arrangement direction has a maximum value of approximately 60 μW and a minimum value of approximately 35 μW, and a maximum of 25 μW of light intensity unevenness occurs. Even in the middle, there is unevenness in the amount of light with a large fluctuation range. On the other hand, in the static eliminator 16B (Document 4) of the second embodiment, the change in the light amount in the arrangement direction has a maximum value of approximately 35 μW and a minimum value of approximately 28 μW, and the light amount unevenness of 7 μW at the maximum remains. In addition, the vertical fluctuation range between adjacent LED chips is greatly improved as compared with that of Document 3, and it is understood that the light amount level is flattened (uniformized) as a whole.

<Embodiment 3>
FIG. 10 is a plan view showing a positional relationship between a static eliminator using the illumination device according to the third embodiment and a photosensitive drum.

  The static eliminator 16C according to the third embodiment has a configuration in which the light buffering portion 62 is disposed in the vicinity of the LED chip 61 in the static eliminator 16B according to the second embodiment. However, as the light buffering part 62, the light buffering part 62 having the dimensions used in the first embodiment is used. Further, the predetermined angle θ is set to 20 degrees as in the case of the second embodiment.

  The inventors produced a static eliminator (illumination device) 16C according to Embodiment 3 (this is referred to as Document 5). Then, the manufactured static eliminator 16C is arranged in parallel along the light irradiation surface 13a of the photosensitive drum 13, and the light irradiation surface 13a is actually irradiated with light to scan the light irradiation surface 13a (LED chip 61). The light amount unevenness along the arrangement direction X) was measured. The measurement results are shown in FIG.

  In FIG. 11, for comparison, the light amount unevenness is also measured for the conventional structure shown in FIG. 13 (this is referred to as Document 3), and the measurement results are also shown.

  As a result, as is clear from FIG. 11, in document 3, the change in the amount of light in the arrangement direction has a maximum value of approximately 60 μW and a minimum value of approximately 35 μW. Even in the middle, there is unevenness in the amount of light with a large fluctuation range. On the other hand, in the static eliminator 16C (Document 5) of the third embodiment, the change in the light amount in the arrangement direction has a maximum value of approximately 33 μW and a minimum value of approximately 28 μW, and the light amount unevenness of 5 μW at the maximum remains. In addition, the vertical fluctuation range between adjacent LED chips is greatly improved as compared with that of Document 3, and it is understood that the light amount level is flattened (uniformized) as a whole.

  As is clear from the measurement results, by using the static eliminators 16A, 16B, and 16C according to the first to third embodiments, the light amount unevenness of the light irradiated on the light irradiation surface 13a of the photosensitive drum 13 is flattened. The amount of charge removed can be made uniform. Accordingly, by mounting the static eliminating devices 16A, 16B, and 16C on the image forming apparatus, the amount of static eliminating light irradiated onto the light irradiation surface 13a of the photosensitive drum 13 can be made uniform, so that the print quality can be improved. .

  Below, the summary of the illuminating device, static elimination apparatus, and image forming apparatus which concern on embodiment of this invention is demonstrated.

  The illuminating device according to the embodiment is configured such that a plurality of light emitting elements 61 are arranged on the substrate 60 and the light buffering portions 62 are arranged on the front side of the light emitting direction of each light emitting element 61.

  According to this configuration, the light reaching the light buffer unit 62 from the light emitting element 61 is not completely blocked, but is partially transmitted, so that the light transmitted through the portion is reduced and the light quantity as a whole is reduced. Unevenness can be flattened. Thereby, the light amount unevenness as a whole can be flattened by arranging the light buffer portion in the region where the light amount increases.

  Further, in the illumination device according to the embodiment, the light emitting element 61 has a configuration in which the light irradiation direction is inclined with respect to the arrangement direction of the substrates 60.

  According to this configuration, the optical axis is inclined with respect to the direction orthogonal to the arrangement direction, and as a result, the irradiation region of the light reaching the side edge portion of the substrate on the front side in the light irradiation direction can be widened.

  Moreover, in the illuminating device which concerns on embodiment, the light buffer part 62 is a translucent member which permeate | transmits light. By forming the light buffering part 62 with a translucent member, the light transmitted through the light buffering part can be reduced.

  Moreover, in the illuminating device which concerns on embodiment, the some light emitting element 61 and the some light buffer part 62 are arranged in parallel. That is, the distance between each light emitting element 61 and each light buffering part 62 facing this is made equal.

  Moreover, in the illuminating device which concerns on embodiment, the light emitting element 61 and the light buffer part 62 are arrange | positioned in parallel with the light irradiation surface 13a of the irradiation target object 13, and the irradiation light of the light emitting element 61 is irradiated. A part of the light is applied to the light irradiation surface 13 a through the light buffer 62. That is, the light amount is gently reduced instead of completely blocking light.

  Moreover, in the illuminating device which concerns on embodiment, the light buffer part 62 is set as the structure provided in the shortest distance position between the light emitting element 61 and the light irradiation surface 13a of the irradiation target object 13. FIG.

  According to this configuration, the amount of light in the irradiation region with the largest amount of light can be reduced on the light irradiation surface 13a of the irradiation target 13, so that unevenness in the amount of light in the entire irradiation region can be reduced.

  Further, in the illumination device according to the embodiment, the light buffering portions 62 are arranged on the substrate 60, and the light irradiation direction of the light emitting elements 61 is parallel to the mounting surface 60 a of the substrate 60 on which the light emitting elements 61 are mounted. It is said.

  According to this configuration, the lighting device can be used as a side light emission type lighting device.

  Further, the static eliminator 16 according to the embodiment is configured such that the illumination devices having the above-described configurations are arranged in parallel to the light irradiation surface 13a of the electrostatic latent image carrier 13 that is an irradiation target.

  According to this configuration, it is possible to flatten unevenness in the amount of light applied to the light irradiation surface 13a of the electrostatic latent image carrier 13 and to uniformize the amount of charge removal.

  Further, the image forming apparatus 1 according to the embodiment is configured to include the static elimination device 16 having the above-described configuration.

  According to this configuration, the unevenness of the amount of light irradiated on the light irradiation surface 13a of the electrostatic latent image carrier 13 can be flattened and the amount of charge removed can be made uniform, so that the print quality can be improved.

  In the image forming apparatus 1 according to the embodiment, the static eliminator 16 is a substrate on which the light emitting elements 61 are arranged with respect to the charging device 15 arranged around the light irradiation surface 13 a of the electrostatic latent image carrier 13. The one surface (main surface) 60 a of 60 is arranged so as to be located on the side opposite to the charging device 15. According to this structure, it can be set as the arrangement structure which the irradiation light from a static elimination apparatus does not wrap around to the charging device side.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is set forth in the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention greatly contributes to all image forming apparatuses in which a static eliminator including a lighting device in which a plurality of light emitting elements are arranged on a substrate is mounted on an image forming unit.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image forming part 11 Optical scanning apparatus 12 Developing apparatus 13 Photosensitive drum (electrostatic latent image carrier: irradiation object)
13a Light irradiation surface 14 Drum cleaning device 15 Charging device 16 (16A, 16B, 16C) Static elimination device 20 Image reading unit 40 Document feeding device (ADF)
50 In-body discharge space 60 Substrate 60a Main surface (mounting surface)
60a1 One side edge 60a2 The other side edge 61 LED chip (light emitting element)
61a Optical axis 62 Optical buffer 63 Light reflector Pa, Pb, Pc, Pd Image station

Claims (10)

  A lighting device, wherein a plurality of light emitting elements are arranged on a substrate, and light buffering portions are arranged on the front side of the light emitting direction of each light emitting element. The lighting device according to claim 1,
The lighting device is characterized in that the light emitting element is provided such that a light irradiation direction is inclined with respect to an arrangement direction of the substrates. The lighting device according to claim 1 or 2,
The lighting device, wherein the light buffering part is a translucent member that transmits light. It is an illuminating device as described in any one of Claim 1- Claim 3, Comprising:
The lighting device, wherein the plurality of light emitting elements and the plurality of light buffering portions are arranged in parallel. It is an illuminating device as described in any one of Claim 2- Claim 4, Comprising:
The light emitting element and the light buffer unit are arranged in parallel to the light irradiation surface of the irradiation object, and a part of the irradiation light from the light emitting element passes through the light buffer unit and is An illumination device that irradiates a light irradiation surface. The lighting device according to claim 5,
The lighting device, wherein the light buffer is provided at a shortest distance between the light emitting element and the light irradiation surface of the irradiation object. The lighting device according to claim 5 or 6,
The light buffer unit is arranged on the substrate, and a light irradiation direction of the light emitting element is parallel to a mounting surface of the substrate on which the light emitting element is mounted.   The static eliminator characterized in that the illumination device according to any one of claims 5 to 7 is arranged in parallel to a light irradiation surface of an electrostatic latent image carrier that is the irradiation object. .   An image forming apparatus comprising the static eliminator according to claim 8. The image forming apparatus according to claim 9, wherein
The static eliminator is configured such that one surface of the substrate on which the light emitting elements are arranged is opposite to the charging device with respect to the charging device arranged around the light irradiation surface of the electrostatic latent image carrier. An image forming apparatus, wherein the image forming apparatus is disposed so as to be positioned.

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