Lens mirror array

Abstract

To provide a lens mirror array capable of improving optical characteristics while allowing a shading member to be mounted on a prescribed part of a surface thereof.SOLUTION: A lens mirror array 1 includes a plurality of optical elements 90 aligned in a first direction. Each of the plurality of optical elements includes: an incidence plane 2 into which light is incident; a reflection plane 3 extending in a second direction orthogonal to the first direction and configured to reflect the light incident via the incidence plane; a protrusion 6 extending in the second direction and including a reflection plane at an apex in a projection direction; and an emission surface 5 configured to emit the light reflected at the reflection plane. The lens mirror array further includes a comb-shaped groove 7, means for storing a shading ink, and a shading member. The comb-shaped groove includes a plurality of linear grooves disposed between a plurality of protrusions aligned in the first direction of the plurality of optical elements, neighboring at one end in the second direction of the plurality of protrusions and having an end face intersecting the second direction, and is structured by connecting the plurality of linear grooves at another end side in the second direction of the plurality of protrusions.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an integrated lens and mirror array (hereinafter referred to as a lens mirror array) that is incorporated into a copier, printer, scanner, or the like. [Background technology]

[0002] For example, a document reader in an image forming apparatus has a lens mirror array for refracting and reflecting light incident from a document surface and focusing the light on a sensor array, while an exposure device in an image forming apparatus for forming an electrostatic latent image on the surface of a photosensitive drum has a lens mirror array for refracting and reflecting light based on an image signal emitted from a light source and focusing the light on the surface of the photosensitive drum.

[0003] The lens mirror array of the exposure device has, for example, a plurality of optical elements that focus light from a plurality of light sources aligned in the main scanning direction onto the surface of the photosensitive drum. The lens mirror array has a structure in which a plurality of optical elements are integrally connected in the main scanning direction. The lens mirror array can be formed, for example, from a transparent resin.

[0004] Each optical element of the lens mirror array has a light blocking member on part of its surface, which blocks light unnecessary for exposure (for example, light that undesirably enters adjacent optical elements). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-094439 Summary of the Invention [Problem to be solved by the invention]

[0006] A lens mirror array has a surface shape consisting of complex and minute irregularities, with multiple optical elements with lens and mirror surfaces arranged at a pitch of less than 1 mm in the main scanning direction, making it extremely difficult to apply a light-blocking member only to desired locations on this surface.

[0007] The problem to be solved by the present invention is to provide a lens mirror array that can provide a light-shielding member at a predetermined portion of the surface and can improve optical characteristics. [Means for solving the problem]

[0008] The lens mirror array of the embodiment includes a plurality of optical elements arranged in a first direction. Each optical element has an incident surface on which light is incident, a reflecting surface extending in a second direction perpendicular to the first direction and reflecting the light incident through the incident surface, a convex portion extending in the second direction and having a reflecting surface at its apex in the protruding direction, and an exit surface from which the light reflected by the reflecting surface is emitted. The lens mirror array also includes comb-shaped grooves, a means for storing light-blocking ink, and a light-blocking member. The comb-shaped grooves are provided between the convex portions of the plurality of optical elements arranged in the first direction, and include a plurality of linear grooves adjacent to one end of the convex portions in the second direction and having an end surface intersecting with the second direction, and the plurality of linear grooves are connected at the other end of the convex portions in the second direction. The means for storing light-blocking ink is provided at the intersection where the bottom surface of the comb-shaped groove intersects with the side surface continuous with the edge of the reflecting surface of the convex portions. The light-shielding member is formed by applying and curing a light-shielding ink to the bottom surfaces of the comb-tooth grooves, the side surfaces of the plurality of convex portions, and the end surfaces of the plurality of linear grooves. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the image forming unit for yellow of the image forming apparatus of FIG. [Figure 3] FIG. 3 is a cross-sectional view showing a reading module incorporated in the scanner of the image forming apparatus of FIG. [Figure 4] FIG. 4 is a partially enlarged perspective view showing a lens mirror array incorporated in the reading module of FIG. [Figure 5] FIG. 5 is a cross-sectional view of the lens mirror array of FIG. 4 taken along an imaginary boundary surface F5-F5 between a plurality of optical elements. [Figure 6] FIG. 6 is a partially enlarged perspective view showing a state in which a light blocking member is provided on the inner surface of the comb-teeth-shaped grooves of the lens mirror array of FIG. [Figure 7] FIG. 7 is a view of the convex portions of the lens mirror array of FIG. 4 as viewed from the main scanning direction. [Figure 8] FIG. 8 is a cross-sectional view of the protrusion of FIG. 7 taken along line F8-F8. [Figure 9] FIG. 9 is a diagram for explaining a method of applying light-blocking ink to the ink application surface of the lens mirror array of FIG. [Figure 10] FIG. 10 is a diagram for explaining how the light-shielding ink spreads onto the ink-coated surface of FIG. 9 immediately after the light-shielding ink is coated thereon. [Figure 11] FIG. 11 is a partially enlarged perspective view showing a state in which a light blocking member is provided on the inner surface of the comb-tooth-shaped groove of a conventional lens mirror array having no recesses. [Figure 12] FIG. 12 is a diagram for explaining how the light-shielding ink spreads immediately after being applied to the ink-applied surface of the conventional lens mirror array of FIG. [Figure 13] FIG. 13 shows the results of applying light-shielding ink to the inner surfaces of the comb-like grooves of the lens mirror array of FIG. 4, with the depth and width of the recesses changed. [Figure 14] FIG. 14 is a cross-sectional view showing a modification of FIG. 4 in which the depth of the recess is made constant. [Figure 15] FIG. 15 is a cross-sectional view showing a modification in which the cross-sectional shape of the recess in FIG. 4 is made rectangular. [Figure 16] FIG. 16 is a perspective view showing a modification in which the recesses of FIG. 4 are provided separately on both sides of the protrusion. [Figure 17] FIG. 17 is a perspective view showing a modification in which the depressions in FIG. 16 are replaced with dots. DETAILED DESCRIPTION OF THE INVENTION

[0010] An image forming apparatus 100 using a lens mirror array 1 according to one embodiment will be described below with reference to the drawings. Note that the scale of each part in each drawing used in the following description of the embodiment may be changed as appropriate. Also, in each drawing used in the following description of the embodiment, the configuration may be omitted to make the description easier to understand. In each drawing, the front-to-back, left-to-right, and up-to-down directions are defined when the image forming apparatus 100 is viewed from the front (the front side of the paper in FIG. 1), and the direction from back to front is indicated by arrow X, the direction from left to right is indicated by arrow Y, and the direction from bottom to top is indicated by arrow Z.

[0011] The image forming apparatus 100 is, for example, an MFP (multifunction peripheral). The image forming apparatus 100 has a printing function, a scanning function, a copying function, an erasing function, a facsimile function, and the like. The printing function is a function for forming a toner image on paper P. The scanning function is a function for reading an image from an original document on which an image has been formed. The copying function is a function for printing an image read from an original document using the scanning function onto paper P using the printing function. The erasing function is a function for erasing an image formed on paper P with an erasable developer.

[0012] As shown in FIG. 1, the image forming apparatus 100 includes a printer 10, a scanner 20, and an operation panel 30.

[0013] Printer 10 is equipped with multiple paper feed cassettes 11, a manual feed tray 12, and multiple paper feed rollers 13. Paper feed cassette 11 stores paper P to be used for printing. Manual feed tray 12 is for manually feeding paper P. Paper feed roller 13 selectively picks up paper P from either paper feed cassette 11 or manual feed tray 12 by rotating.

[0014] The printer 10 includes four toner cartridges 141, 142, 143, and 144, four image forming units 151, 152, 153, and 154, an optical scanning device 16, a transfer belt 17, a secondary transfer roller 18, and a fixing unit 19.

[0015] Toner cartridges 141 to 144 contain toner to be supplied to image forming units 151 to 154, respectively. Toner cartridge 141 contains yellow (Y) toner. Toner cartridge 142 contains magenta (M) toner. Toner cartridge 143 contains cyan (C) toner. Toner cartridge 144 contains black (K) toner. The toner color combination is not limited to YMCK, and other color combinations may also be used. Furthermore, the toner may be one that loses its color at temperatures higher than a predetermined temperature.

[0016] Image forming units 151 to 154 receive toner from toner cartridges 141 to 144, respectively, and form toner images of different colors. Image forming unit 151 forms a yellow (Y) toner image. Image forming unit 152 forms a magenta (M) toner image. Image forming unit 153 forms a cyan (C) toner image. Image forming unit 154 forms a black (K) toner image.

[0017] The image forming units 151 to 154 have the same configuration except for the difference in toner. Therefore, here, the image forming unit 151 for yellow will be described as a representative with reference to Figure 2, and descriptions of the image forming units 152 to 154 for the other colors will be omitted. The yellow image forming unit 151 includes a photosensitive drum 41, a charging device , a developing device 43, a primary transfer roller 44, a cleaner 45, and a discharging lamp .

[0018] The photosensitive drum 41 has a surface that receives the light beam BY irradiated from the optical scanning device 16. A lens mirror array 1 is located between the optical scanning device 16 and the photosensitive drum 41. The optical scanning device 16 forms an electrostatic latent image on the surface of the photosensitive drum 41. The charging device 42 applies a positive charge to the surface of the photosensitive drum 41. The developing device 43 develops the electrostatic latent image on the surface of the photosensitive drum 41 using yellow toner D supplied from a toner cartridge 141. That is, the developing device 43 forms a yellow toner image on the surface of the photosensitive drum 41.

[0019] Image forming unit 151 also includes a primary transfer roller 44 at a position facing photosensitive drum 41 with transfer belt 17 sandwiched therebetween. Primary transfer roller 44 generates a transfer voltage between itself and photosensitive drum 41. As a result, primary transfer roller 44 transfers (primary transfer) the yellow toner image on the surface of photosensitive drum 41 onto the surface of transfer belt 17, which is in contact with photosensitive drum 41.

[0020] The cleaner 45 removes toner remaining on the surface of the photosensitive drum 41. The charge removal lamp 46 removes charge remaining on the surface of the photosensitive drum 41.

[0021] In accordance with input image data, the optical scanning device 16 irradiates the surfaces of the photosensitive drums 41 of the image forming units 151, 152, 153, and 154 with light beams BY, BM, BC, and BK, respectively. The light beams BY, BM, BC, and BK are based on image data of each color obtained by color-separating the image data into Y, M, C, and K colors, respectively.

[0022] The optical scanning device 16 emits a light beam BY in accordance with image data of the Y component to form an electrostatic latent image for yellow on the surface of the photosensitive drum 41 of the image forming unit 151. Similarly, the optical scanning device 16 emits light beams BM, BC, and BK in accordance with image data of the M, C, and K components to form electrostatic latent images for each color on the surfaces of the photosensitive drums 41 of the image forming units 152, 153, and 154.

[0023] The image data input to the optical scanning device 16 is, for example, image data read from an original document by the scanner 20. Alternatively, the image data input to the optical scanning device 16 is image data transmitted to the image forming device 100 from a device other than the image forming device 100.

[0024] The transfer belt 17 is stretched endlessly and rotates by rotating the drive roller 171 around which the transfer belt 17 is wound. As the transfer belt 17 rotates, it transports the toner images of each color formed by the image forming units 151 to 154 on top of each other on the surface of the transfer belt 17 to a transfer area where the secondary transfer roller 18 faces.

[0025] The secondary transfer roller 18 faces the drive roller 171 with the transfer belt 17 sandwiched therebetween. The secondary transfer roller 18 transfers (secondary transfer) the toner image formed on the transfer belt 17 onto the paper P passing between the secondary transfer roller 18 and the toner image formed on the transfer belt 17.

[0026] The fixing unit 19 heats and presses the paper P. The fixing unit 19 includes a heating roller 191 and a pressure roller 192 that face each other with the transport path of the paper P sandwiched between them. The heating roller 191 includes a heat source such as a heater. The heating roller 191, heated by the heat source, heats the paper P. The pressure roller 192 presses the paper P that passes between the pressure roller 192 and the heating roller 191. Thus, the fixing unit 19 fixes the toner image transferred onto the paper P.

[0027] The printer 10 also includes a duplex unit 50 and a paper output tray 60. The duplex unit 50 prepares the paper P so that printing can be performed on the reverse side. The duplex unit 50 switches back the paper P to turn it over, and sends it to the transfer area between the transfer belt 17 and the secondary transfer roller 18. The paper output tray 60 receives the paper P that has been ejected after printing has been completed.

[0028] The scanner 20 reads an image from a document, etc. The scanner 20 includes a reading module 70 and a document feeder 80.

[0029] The reading module 70 shines illumination light onto the surface of the document having the image to be read (hereinafter referred to as the document surface), and receives the reflected light with an image sensor 76 (FIG. 3) and converts it into a digital signal. In this way, the reading module 70 reads the image from the document surface. The reading module 70 includes a lens mirror array 1 (FIG. 3) that guides the reflected light from the document to the image sensor 76.

[0030] The document feeder 80 is, for example, an ADF (auto document feeder). The document feeder 80 transports documents placed on a document tray 81 one after another through a document glass 82. The reading module 70 reads images from the documents transported to the document glass 82. The document feeder 80 may be provided with another reading module for reading images from the back side of the documents.

[0031] The operation panel 30 is a man-machine interface that performs input and output between the image forming apparatus 100 and the operator of the image forming apparatus 100. The operation panel 30 includes, for example, a touch panel 31 and an input device 32.

[0032] The touch panel 31 is a stack of a display, such as a liquid crystal display or an organic EL display, and a pointing device that accepts touch input. The display of the touch panel 31 displays a screen that notifies the operator of the image forming apparatus 100 of various information. The touch panel 31 also accepts touch operations by the operator.

[0033] The input device 32 accepts operations by an operator of the image forming apparatus 100. The input device 32 is, for example, a keyboard, a keypad, or a touchpad.

[0034] 3, the reading module 70 includes a lens mirror array 1, two reflectors 72, two light guides 74, an image sensor 76, and a holder 78. The holder 78 positions and holds the lens mirror array 1, the reflectors 72, the light guides 74, and the image sensor 76 (a substrate 75 on which the image sensor 76 is mounted).

[0035] FIG. 4 is a partially enlarged perspective view of the lens mirror array 1, and FIG. 5 is a cross-sectional view of the lens mirror array 1 taken along line F5-F5 in FIG. 4. The lens mirror array 1 has an elongated structure extending in the main scanning direction (only a portion of which is shown in FIG. 4). The lens mirror array 1 can be formed by integral molding using a resin mold. The lens mirror array 1 forms an erect image of the image on the document surface on the image sensor 76. Therefore, by moving the reading module 70 along the document glass 82 in the sub-scanning direction indicated by arrow Y in FIG. 1, the entire image on the document surface can be read by the image sensor 76.

[0036] The image sensor 76 has an elongated structure extending in the main scanning direction indicated by the arrow X in FIG. 3. The image sensor 76 is a line sensor in which a plurality of imaging elements that convert light into electrical signals are arranged in a line in the main scanning direction. The image sensor 76 is one or more line sensors. The image sensor 76 can be configured, for example, by a Charge Coupled Device (CCD), a Complimentary Metal Oxide Semiconductor (CMOS), or other imaging elements.

[0037] The holder 78 has an elongated structure extending in the main scanning direction. The holder 78 can be formed by integral molding of resin using a mold. The holder 78 has a pair of side walls 781 arranged along the main scanning direction, a pair of end walls 782 (only the rear end wall is shown in FIG. 3) arranged at both longitudinal ends of the side walls 781, and a partition wall 783 connecting the inner surfaces of the vertically middle parts of the pair of side walls 781 and the inner surfaces of the vertically middle parts of the pair of end walls 782. A bulging portion 784 bulges upward in the middle part of the partition wall 783 in the sub-scanning direction (the left-right direction in the figure). The bulging portion 784 has an elongated structure extending in the main scanning direction.

[0038] The bulging portion 784 of the holder 78 has a rectangular slit-shaped aperture 785 extending in the main scanning direction at approximately the center in the sub-scanning direction. The aperture 785 allows reflected light from the document surface to pass through, narrowing the width of the reflected light in the sub-scanning direction and directing it to the lens mirror array 1. The holder 78 holds the lens mirror array 1 inside the bulging portion 784, i.e., below the aperture 785 in the figure. The width of the aperture 785 in the sub-scanning direction is smaller than the width at which the reflected light from the document that has passed through the aperture 785 is incident on the multiple incident-side lens surfaces 2 (Figures 4 and 5) of the lens mirror array 1. The lens mirror array 1 is positioned so that the optical axis of the incident-side lens surface 2 passes through the center of the aperture 785 in the sub-scanning direction.

[0039] The holder 78 holds the reflector 72 and the light guide 74 inside the two side walls 781 and above the partition wall 783 on both sides of the bulging portion 784 in the sub-scanning direction. The holding structure for the reflector 72 and the light guide 74 will not be illustrated or described.

[0040] The reflector 72 is, for example, a long rectangular plate extending in the main scanning direction. The reflector 72 has a reflective surface facing a light diffusion section (not shown) of the light guide 74, which has an uneven surface or is coated with white ink. The reflector 72 has its reflective surface coated with white ink or is made of white resin formed into a rectangular plate. The reflector 72 has a function of reflecting light leaking from the light diffusion section of the light guide 74 back to the light guide 74.

[0041] The light guide 74 is, for example, a transparent resin member having a generally cylindrical shape that is elongated in the main scanning direction, and has the aforementioned light diffusion portion along the longitudinal direction on part of its surface. The light guide 74 guides light emitted from an LED light source (not shown) or the like that is disposed at one end of the light guide 74 in the longitudinal direction. The reflector 72 reflects light that leaks from the light diffusion portion of the light guide 74 and returns it to the light guide 74.

[0042] The two light guides 74 need to be spaced a certain distance apart in the sub-scanning direction to prevent the bulging portion 784 from casting a shadow on the illumination light because there is a bulging portion 784 of the partition wall 783 of the holder 78 between them. On the other hand, if the two light guides 74 are spaced apart in the sub-scanning direction, the angle of the illumination light that strikes the image reading area on the document surface increases, and the change in illuminance when the distance between the document glass 82 and the document surface changes increases. For this reason, it is desirable to position the two light guides 74 as close as possible to each other in the sub-scanning direction.

[0043] The holder 78 has a plurality of bosses 786 protruding downward from the illustrated lower surface of the partition wall 783. The bosses 786 are provided, for example, at three locations, namely, at both ends and the center of the partition wall 783 in the main scanning direction, and on both sides of the bulging portion 784 in the sub-scanning direction. These six bosses 786 are each used to fix the substrate 75 to the holder 78 using a screw 787. The holder 78 is provided with a plurality of bosses 788 for positioning the substrate 75 in the holder 78.

[0044] The structure of the lens mirror array 1 will be described below with reference to Figs. 3 to 8. In Fig. 3, the direction perpendicular to the paper surface is the main scanning direction (first direction), and the left-right direction in the drawing in which the reading module 70 moves is the sub-scanning direction. In Fig. 4, the main scanning direction is indicated by arrow X. Fig. 5 is a cross-sectional view of the lens mirror array 1 of Fig. 4 taken along an imaginary boundary surface (the surface indicated by F5-F5) between the multiple optical elements 90.

[0045] The lens mirror array 1 has a structure in which a plurality of transparent optical elements 90 of the same shape are aligned and integrally arranged in the main scanning direction. Each optical element 90 has a shape that is symmetrical with respect to an imaginary center plane that passes through the center of the optical element 90 in the main scanning direction and is perpendicular to the main scanning direction. The plurality of optical elements 90 are aligned in the main scanning direction at a pitch of approximately 0.3 to 1.5 mm.

[0046] In addition to the multiple optical elements 90, the lens mirror array 1 has extensions (not shown) at both ends in its longitudinal direction that can be contacted by an operator when gripping the lens mirror array 1. The lens mirror array 1 of this embodiment can be formed by integral molding of transparent resin. The lens mirror array 1 can also be formed from transparent glass.

[0047] Each optical element 90 of the lens mirror array 1 guides diffused light from an object point so that it forms an image at an image point on the image plane. The axis of light passing through the optical element 90 is shown in FIG. 5. One optical element 90 forms an image on the image plane of light from multiple object points aligned in the main scanning direction. For example, one optical element 90 forms an image on the image plane of light from object points arranged within a width that is two to five times the pitch of the optical elements 90 in the main scanning direction. Each optical element 90 of the lens mirror array 1 reflects and outputs the incident light twice, forming an erect image of the object point at the image point.

[0048] Each optical element 90 of the lens mirror array 1 has an incident-side lens surface 2 (incident surface), an upstream-side reflecting surface 3 (reflecting surface), a downstream-side reflecting surface 4, and an exit-side lens surface 5 (exit surface) on its surfaces. The incident-side lens surface 2, downstream-side reflecting surface 4, and exit-side lens surface 5 are free-form surfaces that are convex outward. The upstream-side reflecting surface 3 is a flat surface.

[0049] The widths in the main scanning direction of incident-side lens surface 2, downstream-side reflective surface 4, and exit-side lens surface 5 are the same as the width in the main scanning direction of optical element 90. In other words, incident-side lens surface 2, downstream-side reflective surface 4, and exit-side lens surface 5 of multiple optical elements 90 connected in the main scanning direction each form a surface that is connected in the main scanning direction.

[0050] In contrast, the upstream reflective surface 3 has a width in the main scanning direction that is narrower than the width of the optical element 90 in the main scanning direction. The upstream reflective surface 3 is located at the top of a convex portion 6 that protrudes a portion of the optical element 90 outward. The convex portion 6 has a width in the main scanning direction that is narrower than the width of the optical element 90 in the main scanning direction, and extends in a direction (second direction) indicated by arrow Y' in Figure 5 that is perpendicular to the main scanning direction. The upstream reflective surface 3 also extends in the direction of arrow Y'.

[0051] One end 301 of the upstream reflecting surfaces 3 of the plurality of optical elements 90, which is close to the incident-side lens surface 2, is connected by a flat connecting surface 302 that is disposed flush with the upstream reflecting surfaces 3. In other words, the upstream reflecting surfaces 3 of the plurality of optical elements 90, together with the connecting surface 302, form a comb-like flat surface. The other end 303 of the upstream reflecting surface 3, which is farther from the connecting surface 302, is curved in an arc shape.

[0052] The incident-side lens surface 2 faces an aperture opening 785 in the bulging portion 784 of the holder 78. In other words, the lens mirror array 1 is fixed to the bulging portion 784 in the state shown in Fig. 3 where the incident-side lens surfaces 2 of the plurality of optical elements 90 face the aperture opening 785. The incident-side lens surface 2 has a positive optical power that allows light that has been reflected by the document surface and passed through the aperture opening 785 to be incident thereon, and refracts and converges this incident light.

[0053] The upstream reflecting surface 3 is adjacent to the incident-side lens surface 2 on the opposite side of the protruding portion 91. The upstream reflecting surface 3 is located on the optical path of the incident light that enters through the incident-side lens surface 2. The upstream reflecting surface 3 totally reflects the light that has entered through the incident-side lens surface 2 towards the downstream reflecting surface 4.

[0054] The downstream reflecting surface 4 is continuous with the incident-side lens surface 2 on the opposite side of the protruding portion 92. The downstream reflecting surface 4 is located on the optical path of the light reflected by the upstream-side reflecting surface 3. The downstream reflecting surface 4 totally reflects the light reflected by the upstream-side reflecting surface 3 toward the output-side lens surface 5. The downstream reflecting surface 4 is a free-form surface with positive optical power that reflects and converges light.

[0055] Exit-side lens surface 5 is continuous with downstream-side reflecting surface 4 on the opposite side of protruding portion 93. Exit-side lens surface 5 is located on the optical path of the light reflected by downstream-side reflecting surface 4. Exit-side lens surface 5 is a free-form surface with positive optical power that transmits and converges the light reflected by downstream-side reflecting surface 4.

[0056] The above-described lens mirror array 1 functions as follows. Light reflected from the document surface is incident on the incident-side lens surface 2 of the plurality of optical elements 90. In other words, light reflected from the document surface placed at the object point is incident on the incident-side lens surface 2. The incident-side lens surface 2 refracts and converges the incident light, forming an intermediate inverted image.

[0057] Upstream-side reflecting surface 3 reflects incident light that has entered through incident-side lens surface 2 toward downstream-side reflecting surface 4. Downstream-side reflecting surface 4 further reflects the light reflected by upstream-side reflecting surface 3 toward exit-side lens surface 5.

[0058] Exit-side lens surface 5 emits the light reflected by downstream-side reflecting surface 4 toward image sensor 76, which is located at the image point. Exit-side lens surface 5 cooperates with downstream-side reflecting surface 4 to form an erect image that is an inverted image of the intermediate inverted image formed by incident-side lens surface 2. The light emitted from exit-side lens surface 5 forms an image on the light-receiving surface of image sensor 76, which is located at the image point.

[0059] The comb-like grooves 7, which will be described later and in which the light-shielding members 8 are provided, have a fine uneven shape as described above, and therefore it is difficult to apply the light-shielding ink neatly and evenly to the inner surfaces of the grooves due to the wetting and spreading of the light-shielding ink. While the light-shielding ink can be easily applied to the bottom surfaces 63, which will be described later, of the comb-like grooves 7, it is difficult to apply the light-shielding ink to the side surfaces 61 and end surfaces 62, which will be described later, of the protrusions 6.

[0060] The convex portion 6, which has the upstream reflective surface 3 at its apex, has a side surface 61 that is continuous with the edge of the upstream reflective surface 3. The side surface 61 of the convex portion 6 is a U-shaped surface that connects a surface that is continuous with both end edges of the upstream reflective surface 3 in the main scanning direction with a surface that is continuous with the other end 303 of the upstream reflective surface 3 that is farther from the incident-side lens surface 2. The side surface 61 is a surface that is approximately perpendicular to the upstream reflective surface 3. The side surface 61 of the convex portion 6 forms part of the inner surface of the comb-tooth-shaped groove 7.

[0061] The lens mirror array 1 has comb-like grooves 7 provided over substantially the entire length in the main scanning direction. The comb-like grooves 7 include a plurality of linear grooves 701 located between the convex portions 6 of each optical element 90 aligned in the main scanning direction. The linear grooves 701 extend along the arrow Y' in Figure 5. The comb-like grooves 7 have a shape in which a plurality of linear grooves 701 are connected so as to surround the other end of the convex portion 6 where the other end 303 of the upstream reflecting surface 3 is located.

[0062] At one end of the plurality of linear grooves 701 adjacent to one end of the convex portion 6 on the entrance lens surface 2 side in the main scanning direction, there is a flat end face 62 that is approximately perpendicular to the direction of arrow Y'. The end face 62 is a surface that is approximately perpendicular to the upstream reflecting surface 3 and extends along the main scanning direction. The plurality of end faces 62 of the plurality of linear grooves 701 between the plurality of convex portions 6 also form part of the inner surface of the comb-tooth-shaped groove 7.

[0063] At the bottom of the comb-tooth-shaped groove 7, there is a comb-tooth-shaped bottom surface 63 that is approximately parallel to the upstream reflecting surface 3. The bottom surface 63 is a surface that is approximately perpendicular to the side surfaces 61 of the multiple convex portions 6 and also approximately perpendicular to the multiple end surfaces 62. The comb-tooth-shaped bottom surface 63 is also a surface that forms part of the inner surface of the comb-tooth-shaped groove 7. On the side farther from the entrance lens surface 2 than the other ends of the multiple convex portions 6, there is an ink-applied surface 64 that is provided approximately flush with the bottom surface 63. The ink-applied surface 64 is a flat surface that is provided over approximately the entire length of the lens mirror array 1 in the main scanning direction.

[0064] 6, a light-shielding member 8 is provided on the inner surfaces of the comb-tooth grooves 7 that do not contribute to guiding effective light, i.e., on the side surfaces 61 of the plurality of convex portions 6, the end surfaces 62 of the plurality of linear grooves 701, and the bottom surface 63 of the comb-tooth grooves 7. The light-shielding member 8 is formed in a thin layer by applying and curing a light-shielding ink to the above-mentioned side surfaces 61, end surfaces 62, and bottom surface 63 using a dispenser, inkjet head, or the like.

[0065] The light-blocking ink is, for example, a highly light-blocking ink (for example, a UV ink containing a light-blocking material such as carbon black, pigment, or dye) whose base material is a polymer with approximately the same refractive index as the lens mirror array 1. The light-blocking member 8 prevents light traveling within the lens mirror array 1 from being reflected or emitted outside the lens mirror array 1.

[0066] As shown in Figure 4, the optical elements 90 have depressions 66 for storing light-blocking ink at intersections 65 where the bottom surfaces 63 of the comb-tooth grooves 7 intersect with the side surfaces 61 of each convex portion 6. The depressions 66 are located on the bottom surfaces 63 near the other ends of the convex portions 6 that are far from the end faces 62. The depressions 66 are U-shaped so as to surround the other ends of each convex portion 6 that are far from the incident-side lens surface 2. Both ends of the depressions 66 extend to near the center of the convex portions 6 in the direction of arrow Y' and terminate at positions away from the end faces 62.

[0067] The recesses 66 may be provided near the intersections 65 where the bottom surfaces 63 of the comb-tooth-shaped grooves 7 intersect with the side surfaces 61 of the plurality of protrusions 6, preferably on the side away from the end surfaces 62 in the direction of arrow Y', and may be provided at least between the plurality of protrusions 6 along the main scanning direction. The recesses 66 may be provided on the bottom surface 63 side of the intersections 65 or on the side surface 61 side of the intersections 65. When the recesses 66 are provided on the side surface 61 side of the intersections 65, they may be provided by, for example, laser processing. Furthermore, the length, position, shape, number, etc. of the recesses 66 along the intersections 65 may be set arbitrarily as long as the recesses 66 are provided at least at the intersections 65 to store light-blocking ink.

[0068] In this embodiment, as shown in Fig. 7, the depth of the recess 66 provided in the bottom surface 63 of the intersection 65 gradually decreases from the other end of the protrusion 6 toward the end surface 62. The depth D of the recess 66 shown in Fig. 8 is approximately 5 to 30 µm, and the width W of the recess 66 is approximately 5 to 30 µm. The cross-sectional shape of the recess 66 intersecting the longitudinal direction is approximately semicircular. The recess 66 functions as a means for storing more light-blocking ink compared to a case where the recess 66 is not provided.

[0069] Here, we will explain how the light-shielding ink spreads onto the inner surface when the light-shielding member 8 is provided on the inner surface of the comb-like grooves 7. Before applying the light-shielding ink to the inner surface of the comb-like grooves 7, the surface is treated with air plasma, excimer UV, or the like to improve the wettability of the light-shielding ink onto the inner surface of the comb-like grooves 7.

[0070] 9, the light-blocking ink is continuously sprayed onto the ink application surface 64 in multiple dots at a constant frequency by a dispenser moving at a constant speed in the main scanning direction. The light-blocking ink sprayed onto the ink application surface 64 wets and spreads over the inner surfaces of the comb-tooth-shaped grooves 7, and is applied to the side surfaces 61, end surfaces 62, and bottom surface 63. Because the amount of light-blocking ink sprayed onto the ink application surface 64 is constant in the main scanning direction, the amount of light-blocking ink allocated to each optical element 90 is also the same.

[0071] The state of the light-blocking ink immediately after it was ejected onto the ink-coated surface 64 was observed using a microscope, and was found to be as shown in Figure 10. The light-blocking ink ejected onto the ink-coated surface 64 flows along the intersections 65 between the side surfaces 61 of the multiple protrusions 6 and the bottom surfaces 63 of the comb-tooth-shaped grooves 7 toward the end surfaces 62, and reaches the intersections 67 where the end surfaces 62 and the bottom surfaces 63 intersect. At this time, a relatively large amount of light-blocking ink is attracted to and accumulates at the corners 68 where the three surfaces, i.e., the side surfaces 61, the bottom surfaces 63, and the end surfaces 62, intersect. In addition, some of the light-blocking ink flowing along the intersections 65 accumulates in the depressions 66. The amount of light-blocking ink that accumulates in the depressions 66 is slightly greater than the amount of light-blocking ink that accumulates at the intersections 65 where there are no depressions 66.

[0072] 6, the light-shielding ink accumulated at the intersections 65, depressions 66, and corners 68 wets and rises up the side surfaces 61 of the convex portions 6 to the edges of the upstream-side reflective surface 3, and the light-shielding ink accumulated at the intersections 67 and corners 68 wets and rises up the end surfaces 62 to the edges of the connecting surfaces 302. If a large amount of light-shielding ink accumulates between the side surfaces 61 and the bottom surface 63, the light-shielding ink that has wetted the side surfaces 61 does not easily fall toward the bottom surface 63. If a small amount of light-shielding ink accumulates between the side surfaces 61 and the bottom surface 63, the light-shielding ink that has wetted the side surfaces 61 easily falls toward the bottom surface 63. In this embodiment, the light-shielding ink successfully wets and rises up to the edges of the upstream-side reflective surface 3 and the connecting surfaces 302, and this state continues until the light-shielding ink hardens, so that the light-shielding member 8 can be provided on the entire inner surfaces of the comb-like grooves 7, as shown in FIG.

[0073] For comparison, a sample of lens mirror array 1 without recesses 66 at intersections 65 was prepared, and under the same conditions except for that, light-shielding ink was sprayed onto ink-coated surface 64 to provide light-shielding material 8 on the inner surfaces of comb-tooth-shaped grooves 7, resulting in areas 9 on the side surfaces 61 of convex portions 6 of multiple optical elements 90 where the light-shielding material 8 was not applied, as shown in Figure 11. The state of the light-shielding ink immediately after spraying it onto ink-coated surface 64 of this sample is shown in Figure 12.

[0074] In the sample in which the depression 66 is not provided at the intersection 65, more light-shielding ink flows to the corner 68 on the side of the end face 62 than in this embodiment (FIG. 10) in which the depression 66 is provided. As a result, the amount of light-shielding ink remaining at the intersection 65 on the other end side of the convex portion 6 is reduced, and the light-shielding ink does not wet up to the side face 61 on the other end side away from the end face 62 of the convex portion 6 in the Y' direction. Furthermore, on the other end side of the convex portion 6, the light-shielding ink does not easily wet up to the edge of the upstream-side reflecting surface 3, and even if it does wet up to the edge, the upper end of the light-shielding ink drops below the edge before it hardens.

[0075] Even in samples that do not have depressions 66 at the intersections 65, it is possible to prevent the above-described occurrence of areas 9 where the light-blocking ink is not applied by increasing the ejection frequency of dots of light-blocking ink by the dispenser to increase the overall amount of light-blocking ink applied. For example, the projection frequency of the light-blocking ink may be controlled so that the amount of light-blocking ink projected increases when the dispenser moves between the multiple convex portions 6.

[0076] However, in this case, the control becomes more complex and the amount of light-blocking ink used increases. Furthermore, a larger amount of light-blocking ink accumulates at the corners 68 of the end face 62 via the intersections 65, and it takes a long time to harden the light-blocking ink on the end face 62 side. In this case, the thickness of the light-blocking member 8 provided on the inner surface of the comb-tooth grooves 7 becomes non-uniform, and the shape of the light-blocking member 8 becomes unstable, adversely affecting the optical characteristics of the lens mirror array 1. Furthermore, applying too much light-blocking ink not only increases costs, but also causes problems such as the ink being applied undesirably to the upstream reflecting surface 3.

[0077] Therefore, as in this embodiment, providing a recess 66 for storing light-blocking ink at the intersection 65 is effective, and the light-blocking member 8 can be neatly provided right up to the edge of the upstream reflecting surface 3 while reducing the amount of light-blocking ink used. The light-blocking member 8 can also be provided with a uniform thickness on the inner surface of the comb-tooth-shaped groove 7, improving the optical characteristics of the lens mirror array 1. That is, according to this embodiment, the recess 66 is simply designed to store the minimum amount of light-blocking ink necessary to provide the light-blocking member 8 up to the edge of the upstream reflecting surface 3 on the other end side of the convex portion 6. By setting the ejection frequency of the light-blocking ink to an appropriate value, the amount of light-blocking ink applied to the end surface 62 can also be controlled to an appropriate amount. This makes it possible to uniformly provide the thickness of the light-blocking member 8 provided on the inner surface of the comb-tooth-shaped groove 7, improving the optical characteristics of the lens mirror array 1.

[0078] The layout, size, shape, etc. of the recesses 66 can be appropriately designed depending on the shape of the convex portion 6, the shape of the upstream reflective surface 3, the shape of the comb-tooth grooves 7, the height of the side surfaces 61 of the convex portions 6 in the protruding direction, the material of the lens mirror array 1, the viscosity of the light-shielding ink, etc., and may be changed as long as the light-shielding member 8 can be neatly arranged on the inner surface of the comb-tooth grooves 7, and is not limited to the above-mentioned embodiment.

[0079] To investigate the optimum values ​​for the depth and width of the recesses 66 in this embodiment, several samples of lens mirror arrays were fabricated and the state of the light-shielding members 8 provided in each sample was observed. The results are shown in Figure 13. Note that the recesses 66 had the shapes shown in Figures 7 and 8, and several types of samples were prepared with different depths D and widths W. For comparison, a sample without recesses 66 (D = 0 μm, W = 0 μm) was also prepared. Furthermore, the amount of light-shielding ink applied, i.e., the ejection frequency, was set to an amount that allowed the light-shielding members 8 to be provided up to the edge of the upstream reflecting surface 3 in all samples.

[0080] In the sample without depression 66 (D=0 μm, W=0 μm), after the light-shielding ink had wetted up to the edge of the upstream reflective surface 3 on the other end side of the convex portion 6, the light-shielding ink at the edge dropped within 2 seconds, creating an area 9 where the light-shielding ink was not applied.

[0081] In contrast, in a sample in which the depth D of the recess 66 is set to 5 to 30 μm and the width W of the recess 66 is set to 5 to 30 μm, such as the lens mirror array 1 of this embodiment, the time it takes for the light-shielding ink that has wetted up to the edge of the upstream reflecting surface 3 to start to drop is longer, and the light-shielding ink can be hardened before it drops from the edge.

[0082] However, in samples in which the depth D of the recess 66 was greater than 30 μm, the light-shielding member 8 could be provided up to the edge of the upstream-side reflecting surface 3, but it took a long time for the light-shielding ink that had accumulated in the recess 66 to harden. Similarly, in samples in which the width W of the recess 66 was greater than 30 μm, the light-shielding member 8 could be provided up to the edge of the upstream-side reflecting surface 3, but it took a long time for the light-shielding ink that had accumulated in the recess 66 to harden.

[0083] That is, it is effective to set the depth D and width W of the recess 66 within the ranges of 5 μm≦D≦30 μm and 5 μm≦W≦30 μm.

[0084] The position and shape of the recess 66 are not limited to those in the above-described embodiment, but may be modified in various ways. For example, as shown in Fig. 14, the depth of the depression 66 may be uniform over its entire length. Also, as shown in Fig. 15, the cross-sectional shape of the depression 66 may be other shapes, such as a rectangle. Also, as shown in Fig. 16, the depression 66 does not necessarily have to be provided continuously in a U-shape surrounding the other end of the protrusion 6, but may be divided into two portions on both sides of the protrusion 6 in the main scanning direction and provided only between multiple protrusions 6. Also, as shown in Fig. 17, multiple hemispherical holes or the like may be provided on both sides of the protrusion 6 in the main scanning direction near the other end of the protrusion 6.

[0085] Although the embodiments and modifications of the present invention have been described above, these embodiments and modifications are presented as examples and are not intended to limit the scope of the invention. These novel embodiments and modifications may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims.

[0086] Other embodiments will be described below. 6. In the lens mirror array of claim 5, the depression is located between a plurality of the protrusions aligned in the first direction of a plurality of the optical elements. 7. In the lens mirror array of claim 5, the recess is located on the side of the plurality of linear grooves farther from the end face. 8. In the above item "7," the depression is located between the plurality of protrusions aligned in the first direction of the plurality of optical elements. 9. In the above item "8," the recess includes a plurality of bottomed holes provided on both sides in the first direction of the other ends in the second direction of the plurality of protrusions. 10. In the lens mirror array of claim 5, the recess is located on the bottom surface of the comb-tooth-shaped groove. [Explanation of symbols]

[0087] 1...lens mirror array, 2...incident lens surface, 3...upstream reflective surface, 302...connecting surface, 4...downstream reflective surface, 5...exit lens surface, 6...convex portion, 61...side surface, 62...end surface, 63...bottom surface, 64...ink application surface, 65...intersection, 66...depression, 67...intersection, 68...corner, 7...comb-tooth groove, 701...linear groove, 8...light-shielding member, 9...area where light-shielding ink is not applied, 90...optical element, 100...image forming device, D...depression depth, W...depression width.

Claims

1. a plurality of optical elements arranged in a first direction; The optical element is an incident surface on which light is incident; a reflecting surface extending in a second direction perpendicular to the first direction and reflecting light incident through the incident surface; a protrusion extending in the second direction and having the reflecting surface at a top thereof in the protruding direction; an exit surface that emits light reflected by the reflecting surface, a plurality of linear grooves provided between the plurality of convex portions of the plurality of optical elements arranged in the first direction, the linear grooves being adjacent to one ends of the plurality of convex portions in the second direction and having end faces intersecting with the second direction, and a comb-like groove connecting the plurality of linear grooves on the other end side of the plurality of convex portions in the second direction; a means for storing light-shielding ink provided at an intersection where a bottom surface of the comb-tooth-shaped groove intersects with a side surface of the plurality of convex portions that is continuous with an edge of the reflecting surface; a light-shielding member formed by applying and curing the light-shielding ink to the bottom surfaces of the comb-tooth-shaped grooves, the side surfaces of the plurality of convex portions, and the end surfaces of the plurality of linear grooves; A lens mirror array having:

2. the means for storing the light-shielding ink is located between the plurality of convex portions of the plurality of optical elements aligned in the first direction; The lens mirror array according to claim 1 .

3. the means for storing the light-shielding ink is located on the other end side of the plurality of linear grooves, the other end side being farther from the end face; The lens mirror array according to claim 1 .

4. the means for storing the light-shielding ink is located between the plurality of convex portions of the plurality of optical elements aligned in the first direction; The lens mirror array according to claim 3 .

5. the means for storing the light-blocking ink is a depression provided at the intersection; The lens mirror array according to claim 1 .

Images