JP2014149536A - Lens array and reading device using the same, exposure device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens array that suppresses the occurrence of a reduction in light intensity, unevenness in light intensity, and a change in imaging characteristics; and an image forming apparatus using the lens array.SOLUTION: A lens array comprises: a first lens; a second lens that is formed in the same shape as that of the first lens, arrayed in a direction orthogonal to an optical axis while being inverted to the first lens by 180°, has an incident surface arranged downstream of an optical path at a position where light is condensed by lens elements arranged in the first lens, and includes a plurality of lens elements that condense again the light made incident on the incident surface on an emission surface; and a light shielding material that has apertures formed to correspond to the lens elements, arranged at least between the emission surface of the first lens and the incident surface of the second lens, and shields the incident light or the emission light with a part other than the apertures. The light shielding material is an ink applied to the surface of the lens, and the thickness of the ink is changed according to the corresponding incident surface and emission surface, so as to determine a diameter of the respective apertures.

Description

  Embodiments described herein relate generally to a lens array and a reading apparatus, an exposure apparatus, and an image forming apparatus using the lens array.

  2. Description of the Related Art Conventionally, image forming apparatuses such as scanners and image forming apparatuses such as printers, copiers, and multifunction peripherals (MFPs) use a lens array in which light emitting elements such as LEDs and a plurality of lenses are arranged as image sensors. An image is formed and the original image is read. Further, by using a light emitting element such as an LED and a lens array, the light beam from the LED is imaged on the photosensitive drum through the lens array, and an image is formed (exposed) on the photosensitive drum. A lens array includes a combination of a plurality of lenses and an aperture. In the lens array, when the optical axes pass between lens surfaces or between lenses through which one light beam passes, the amount of light decreases, the amount of light varies unevenly, and the imaging characteristics easily change.

  Therefore, by increasing the aperture diameter of the exit side lens array relative to the entrance side lens array, the light incident on the lens portion of the entrance side lens array is emitted from the lens portion of the exit side lens array located on the exit side. A technique for increasing the brightness of an erecting equal-magnification image by gradually increasing the cross-sectional area of the light guide is disclosed. In this case, two types of lenses having different lens array shapes are used in combination.

JP 2000-292739 A

  As described above, when two types of lenses having different lens array shapes are combined, it is necessary to mold the lenses with different molds and different cavities, and it is necessary to match the positions of the lenses in the main scanning and sub-scanning directions. It becomes difficult. Furthermore, even if the relative position can be adjusted under certain conditions such as temperature and humidity, the relative position shift in the main scanning and sub-scanning directions of the lens varies depending on the lens under different temperatures and humidity. Occurs, and the light amount is reduced, the light amount is uneven, and the imaging characteristics are likely to change.

  SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, it is an object of the present invention to provide a lens array that is unlikely to cause a decrease in light amount, unevenness in light amount, and change in imaging characteristics, and a reading device, an exposure device, and an image forming apparatus using the lens array. To do.

  A lens array according to an embodiment includes a plurality of lens elements that are arranged in a direction perpendicular to the optical axis and collect light incident on an incident surface from an object point by the lens elements disposed on the incident surface and the output surface. A first lens having the same shape as the first lens, arranged in a direction orthogonal to the optical axis in a state of being inverted by 180 degrees with respect to the first lens, and disposed on the first lens. A second lens having a plurality of lens elements in which an incident surface is disposed downstream of an optical path at a position where light is collected by the lens element, and the light incident on the incident surface is again condensed by the emission surface; Apertures corresponding to the lens elements of the lens and the second lens are formed, arranged at least between the exit surface of the first lens and the entrance surface of the second lens, and the incident or exiting light is transmitted in a portion other than the aperture With light shielding material The light shielding material is ink applied to the surface of the first lens or the second lens, and the diameter of the aperture is determined by changing the thickness of the ink for each corresponding incident surface and outgoing surface. Yes.

1 is a configuration diagram of an image forming apparatus according to Embodiment 1. FIG. FIG. 2 is a configuration diagram illustrating an enlarged part of an image forming unit according to the first embodiment. 1 is a configuration diagram of an image reading device (image sensor) in Embodiment 1. FIG. 1 is a configuration diagram of a lens array used in Embodiment 1. FIG. FIG. 6 is a configuration diagram of a lens array used in Embodiment 2. FIG. 6 is a configuration diagram of a lens array used in Embodiment 3. FIG. 6 is a configuration diagram of a lens array used in a fourth embodiment. FIG. 6 is a configuration diagram of a lens array used in Embodiment 5. FIG. 10 is a configuration diagram of a lens array used in Embodiment 6. FIG. 10 is a configuration diagram of a lens array used in a modification of the fifth embodiment. FIG. 10 is a configuration diagram of a lens array used in a modification of the sixth embodiment.

  Embodiments for carrying out the invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected about the same location.

<Embodiment 1>
FIG. 1 is a configuration diagram of an image forming apparatus according to the present embodiment. In FIG. 1, an image forming apparatus 10 is, for example, an MFP (Multi-Function Peripherals), a printer, a copier, or the like, which is a multifunction peripheral. In the following description, an MFP will be described as an example.

  A transparent glass platen 12 is provided above the main body 11 of the MFP 10, and an automatic document feeder (ADF) 13 is provided on the platen 12 so as to be freely opened and closed. An operation panel 14 is provided on the upper portion of the main body 11. The operation panel 14 has various keys and a touch panel type display unit.

  A scanner unit 15 as a reading device is provided below the ADF 13 in the main body 11. The scanner unit 15 generates image data by reading a document sent by the ADF 13 or a document placed on a document table, and includes a contact image sensor 16 (hereinafter simply referred to as an image sensor). The image sensor 16 is arranged in the main scanning direction (the depth direction in FIG. 1).

  When reading the image of the document placed on the document table 12, the image sensor 16 reads the document image line by line while moving along the document table 12. This is executed over the entire document size, and one page of document is read. When reading an image of a document sent by the ADF 13, the image sensor 16 is at a fixed position (the position shown in the figure).

  Further, a printer unit 17 is provided at the center of the main body 11, and a plurality of cassettes 18 for storing various sizes of paper are provided at the bottom of the main body 11. The printer unit 17 includes a photosensitive drum and a scanning head 19 including an LED as an exposure device, and scans the photosensitive member with light beams from the scanning head 19 to generate an image.

  The printer unit 17 processes image data read by the scanner unit 15 or image data created by a PC (Personal Computer) or the like to form an image on a sheet (details will be described later). The printer unit 17 is a tandem color laser printer, for example, and includes image forming units 20Y, 20M, 20C, and 20K for each color of yellow (Y), magenta (M), cyan (C), and black (K). The image forming units 20Y, 20M, 20C, and 20K are arranged below the intermediate transfer belt 21 in parallel from upstream to downstream. The scanning head 19 also has a plurality of scanning heads 19Y, 19M, 19C, and 19K corresponding to the image forming units 20Y, 20M, 20C, and 20K.

  FIG. 2 is an enlarged configuration diagram illustrating the image forming unit 20K among the image forming units 20Y, 20M, 20C, and 20K. In the following description, since the image forming units 20Y, 20M, 20C, and 20K have the same configuration, the image forming unit 20K will be described as a representative.

  As shown in FIG. 2, the image forming unit 20K includes a photosensitive drum 22K that is an image carrier. A charging charger 23K, a developing device 24K, a primary transfer roller 25K, a cleaner 26K, a blade 27K, and the like are arranged around the photosensitive drum 22K along the rotation direction t. The exposure position of the photosensitive drum 22K is irradiated with light from the scanning head 19K to form an electrostatic latent image on the photosensitive drum 22K.

  The charging charger 23K of the image forming unit 20K uniformly charges the entire surface of the photosensitive drum 22K. The developing device 24K supplies a two-component developer containing black toner and a carrier to the photosensitive drum 22K by a developing roller 24a to which a developing bias is applied. The cleaner 26K removes residual toner on the surface of the photosensitive drum 22K using the blade 27K.

  As shown in FIG. 1, a toner cartridge 28 for supplying toner to the developing devices 24Y to 24K is provided above the image forming units 20Y to 20K. The toner cartridge 28 includes toner cartridges of yellow (Y), magenta (M), cyan (C), and black (K).

  The intermediate transfer belt 21 moves cyclically. The intermediate transfer belt 21 is stretched around a driving roller 31 and a driven roller 32. The intermediate transfer belt 21 is in contact with the photosensitive drums 22Y to 22K. A primary transfer voltage is applied to the position of the intermediate transfer belt 21 facing the photosensitive drum 22K by the primary transfer roller 25K, and the toner image on the photosensitive drum 22K is primarily transferred to the intermediate transfer belt 21.

  A secondary transfer roller 33 is disposed opposite to the drive roller 31 that stretches the intermediate transfer belt 21. When the sheet S passes between the driving roller 31 and the secondary transfer roller 33, a secondary transfer voltage is applied to the sheet S by the secondary transfer roller 33. The toner image on the intermediate transfer belt 21 is secondarily transferred to the paper S. A belt cleaner 34 is provided near the driven roller 32 of the intermediate transfer belt 21.

  As shown in FIG. 1, a conveyance roller 35 that conveys the paper S taken out from the paper feed cassette 18 is provided between the paper feed cassette 18 and the secondary transfer roller 33. Further, a fixing device 36 is provided downstream of the secondary transfer roller 33. Further, a conveyance roller 37 is provided downstream of the fixing device 36. The conveyance roller 37 discharges the paper S to the paper discharge unit 38.

  Further, a reverse conveyance path 39 is provided downstream of the fixing device 36. The reverse conveyance path 39 reverses the sheet S and guides it in the direction of the secondary transfer roller 33, and is used when performing duplex printing.

  Next, the configuration of the scanning head 19 will be described with reference to FIG. 2 using the scanning head 19K as a representative example. The scanning head 19K faces the photosensitive drum 22K and functions as an exposure device. The photosensitive drum 22K rotates at a preset rotation speed and can store electric charges on the surface. The photosensitive drum 22K is exposed to light from the scanning head 19K and exposed to light, and the surface of the photosensitive drum 22K is statically exposed. An electrostatic latent image is formed.

  The scanning head 19 </ b> K has a lens array 50, and the lens array 50 is supported by the holding member 41. The holding member 41 has a support 42 at the bottom, and the support 42 is provided with an LED element 43 that is a light emitting element. The LED elements 43 are provided at regular intervals in a straight line in the main scanning direction. Further, a substrate (not shown) including a driver IC that controls light emission of the LED element 43 is disposed on the support 42. The detailed configuration of the lens array 50 will be described later.

  The drive IC constitutes a control unit, generates a control signal for the scanning head 19K based on the image data, and causes the LED element to emit light with a predetermined light amount according to the control signal. The light beam emitted from the LED element 43 enters the lens array 50, passes through the lens array 50, forms an image on the photosensitive drum 22K, and an image is formed on the photosensitive drum 22K. A cover glass 44 is attached to the upper part (outgoing side) of the scanning head 19K.

  FIG. 3 is an explanatory diagram showing a configuration of the image sensor 16 which is an image reading apparatus. The image sensor 16 reads an image of a document placed on the document table 12 or an image of a document fed by the ADF 13 according to an operation on the operation panel 14. The image sensor 16 is a one-dimensional sensor arranged in the main scanning direction and includes a housing 45. The housing 45 is disposed on a substrate 46, and two LED line illumination devices 47 and 48 that irradiate light in the direction of the document are disposed on the upper surface of the housing 45 on the document table 12 side in the main scanning direction (the depth direction in the figure). ) So as to extend. The LED line illumination devices 47 and 48 include an LED array and a light guide. The light source is not limited to the LED, and may be a fluorescent tube, a xenon tube, a cold cathode tube, an organic EL, or the like.

  A lens array 50 is supported between the LED line illumination devices 47 and 48 at the top of the housing 45, and a sensor 49 made up of a CCD, CMOS, or the like is mounted on the substrate 46 at the bottom of the housing 45. Yes. The LED line illumination devices 47 and 48 irradiate the image reading position of the document on the document table 12, and the light reflected at the image reading position enters the lens array 50. The lens array 50 functions as an erecting equal-magnification lens. The light incident on the lens array 50 is emitted from the exit surface of the lens array 50 and forms an image on the sensor 49. The imaged light is converted into an electric signal by the sensor 49, and the electric signal is transferred to a memory unit (not shown) of the substrate 46.

  Next, the configuration of the lens array 50 (imaging element array) will be described. 4A and 4B are configuration diagrams of the lens array 50 used in the present embodiment. FIG. 4A is a top view of the lens array 50, and FIG. 4B is a cross-sectional view of the lens array 50 in the sub-scanning direction. 4C is a cross-sectional view of the lens array 50 in the main scanning direction.

  As shown in FIGS. 4A to 4C, in the lens array 50, the first lens 51 and the second lens 52 having the same shape are arranged to face each other, and the incident surfaces of the lenses 51 and 52 are arranged. On the exit surface, a lens element (from now on, each lens element disposed on the entrance surface 53, exit surface 54, entrance surface 55, exit surface 56, lens 53, lens 54, lens 55, lens 56 is the same. (Used in meaning) are arranged in a row.

  The first lens 51 is arranged in a direction orthogonal to the optical axis, and the light (L1) incident on the incident surface 53 from the object point is formed by a pair of the lens 53 and the lens 54, and the lens elements on the respective incident surfaces and the output surface. Collect light for each combination. The second lens 52 is formed in the same shape as the first lens 51, and is a direction orthogonal to the optical axis in a state where the second lens 52 is inverted by 180 degrees with a straight line extending in the main scanning direction as the rotation center. The lenses (elements) 55 are arranged opposite to each other downstream of the optical paths at the positions where the light is condensed by the lens (element) 53 and the lens (element) 54 of the first lens 51. The light incident on 55 is condensed again by the lenses 55 and 56 on the entrance surface 55 and the exit surface 56.

  A light shielding material 57 is provided on the surface of the emission surface 54 of the first lens. An aperture (hole) corresponding to the combination of the lens elements of the first lens 51 and the second lens 52 is formed in the light shielding material 57, and light emitted from the emission surface 54 of the first lens 51 is each aperture. Shield from light at other parts. Then, the light (L2) whose unnecessary light is shielded by the light shielding material 57 passes through the incident surface 55 and the exit surface 56 of the second lens 52, and is formed as an erecting equal-magnification image on the image surface. .

  The light shielding member 57 is formed by applying ink around the lens (element) 54 of the first lens 51, or provided with an aperture (hole) corresponding to each lens element in a sheet-like member. Is positioned with respect to the emission surface 54 and bonded thereto.

  Therefore, according to this embodiment, the following effects are produced.

(1) In the lens array, when the optical axis between the lens elements passes through one light beam, the imaging characteristics, the light amount, and the light amount unevenness are greatly deteriorated. Since the lens 53 and the lens 54 of the first lens 51 and the lens 55 and the lens 56 of the second lens 52 are determined in position accuracy in the main scanning direction and the sub-scanning direction based on the accuracy of the mold, the first lens 51 The relative positional accuracy in the main scanning direction and the sub-scanning direction of each lens element on the entrance surface and exit surface, and on the entrance surface of the second lens 52 and each lens element on the exit surface can be set with high accuracy.

(2) As described above, the first lens 51 and the second lens 52 have the same shape, and the second lens 52 is rotated 180 degrees around the axis extending in the main scanning direction. By being arranged to face the first lens 51, each lens (element) on the first lens 51 and the first lens 51, without securing the absolute positional accuracy of each lens element (53, 54, 55, 56), The lenses (elements) on the second lens 52 are made in the same way. Therefore, the optical axes of the lens elements on the entrance surface 53 and the exit surface 54 of the first lens 51 and the lens 55 and the exit surface 56 of the second lens 52 are not displaced relative to each other in the main scanning direction and the sub scanning direction. Can be arranged.

(3) The outer periphery of the incident surface 53 of the first lens 51 is not a straight line, but has a curved surface shape so that unevenness in the amount of light is minimized. Further, since the entire surface is a lens surface, unnecessary light is prevented from entering the incident surface 53.

(4) Of the light that has passed through the entrance surface 53 of the first lens 51, all of the light (L2) that has passed through the light shielding material 57 provided on the exit surface 54 side reaches the image plane. Even when the first lens 52 and the second lens 52 are arranged eccentrically, it is possible to reduce the light amount loss and the deterioration amount of the light amount unevenness.

<Embodiment 2>
FIG. 5 is a configuration diagram of a lens array used in the present embodiment, FIG. 5A is a top view of the lens array 50, FIG. 5B is a cross-sectional view of the lens array 50 in the sub-scanning direction, FIG. 5C is a cross-sectional view of the lens array 50 in the main scanning direction.

  As shown in FIGS. 5A to 5C, the lens array 50 in the present embodiment is provided with a light shielding material 58 on the surface of the incident surface 55 of the second lens 52 as compared with the first embodiment. Is different. Further, the diameter of the aperture formed on the light shielding material 58 on the incident surface 55 side of the second lens 52 is formed larger than the diameter of the aperture formed on the light shielding material 57 on the output surface 54 side of the first lens 51. Has been. The light shielding material 58 is formed by applying ink around the lens 55 of the second lens 52, or a sheet-like member provided with an aperture (hole), like the light shielding material 57. Positioned and bonded to the surface 55. When creating an erecting equal-magnification image, all the lens elements are convex lenses. When a convex lens is considered with its apex facing upward, the aperture diameter decreases as the upper surface of the ink approaches the apex of the lens. Since the first lens 51 and the second lens 52 have the same shape, the distance from the apex of the bottom surface of the lens element is the same. When ink is applied by utilizing this, the ink thickness on the incident surface side of the second lens 52 is made thinner than the ink thickness on the emission surface side of the first lens 51 (the ink upper surface from the lens apex). The aperture diameter is made relatively large.

  Therefore, according to the present embodiment, in addition to the same effects as (1), (2), and (3) of the first embodiment, the first lens 51 and the second lens 52 are arranged eccentrically. Even in such a case, the light shielding material 57 on the emission surface 54 side of the first lens 51 determines which light beam is allowed to pass, and the light shielding material 58 on the incident surface 55 side of the second lens 52 has the first Next to the regular lens 55 to which light should enter when there is no eccentricity on the incident surface of the second lens 52 because the lens 51 and the second lens 52 are arranged eccentrically. There is an effect that stray light generated when a light ray enters 55 can be cut. In addition, even if the first lens 51 and the second lens 52 are decentered in the main scanning direction and the sub-scanning direction, the light beam is not blocked by the decentering up to the aperture radius difference. Play.

<Embodiment 3>
6A and 6B are configuration diagrams of the lens array 50 used in this embodiment. FIG. 6A is a top view of the lens array 50, and FIG. 6B is a cross-sectional view of the lens array 50 in the sub-scanning direction. FIG. 6C is a cross-sectional view of the lens array 50 in the main scanning direction.

  As shown in FIGS. 6A to 6C, the lens array 50 in this embodiment is closer to the object point side, that is, in the vicinity of the incident surface 53 of the first lens 51 than in the second embodiment. The difference is that a light shielding material 59 is provided apart from the incident surface 53. The light shielding material 59 is formed with a slit whose width in the sub-scanning direction changes at the lens array pitch period on the incident surface 53 of the first lens 51. In addition, since the light shielding material 59 is not in contact with the incident surface 53 of the first lens 51, it is preferable that the light shielding material 59 is formed by cutting out from a sheet-like member.

  Therefore, according to the present embodiment, in addition to the same effects as those of the second embodiment, stray light generated at the lens edge portion can be cut off at the lens 53 sub-scanning direction end portion of the first lens 51 and the light shielding material 59. By appropriately setting the change in the width of the slit portion in the sub-scanning direction that changes at each main scanning direction position of the slit so that the amount of light on the image plane is constant even if the object point position is changed There is an effect that the unevenness of the light amount can be further reduced.

<Embodiment 4>
7A and 7B are configuration diagrams of the lens array 50 used in this embodiment. FIG. 7A is a top view of the lens array 50, and FIG. 7B is a cross-sectional view of the lens array 50 in the sub-scanning direction. FIG. 7C is a cross-sectional view of the lens array 50 in the main scanning direction.

  As shown in FIGS. 7A to 7C, the lens array 50 in the present embodiment has a light shielding material 60 provided near the incident surface 53 of the first lens 51 as compared with the third embodiment. The shape is different. That is, the light shielding material 60 in the vicinity of the incident surface 53 of the first lens 51 includes a slit portion whose width in the sub-scanning direction changes with the lens array pitch period on the incident surface 53 and the incident surface of the first lens 51 from the object point. And a boundary light shielding portion that shields light incident on the boundary between the lens elements at 53.

  Therefore, according to the present embodiment, in addition to the same effects as those of the third embodiment, the effect of enabling the stray light incident on the boundary between the lens elements arranged on the incident surface 53 of the first lens 51 to be cut can be obtained. Play.

<Embodiment 5>
FIG. 8 is a configuration diagram of a lens array used in the present embodiment, FIG. 8A is a top view of the lens array 50, FIG. 8B is a cross-sectional view of the lens array 50 in the sub-scanning direction, FIG. 8C is a sectional view of the lens array 50 in the main scanning direction, and FIG. 8D is a bottom view of the lens array 50.

  As shown in FIGS. 8A to 8D, the lens array 50 in the present embodiment has lens elements and apertures arranged two-dimensionally, and also shields the surface of the incident surface 53 of the first lens 51 from light. A material 60 is provided. In addition, the light shielding material 60 on the incident surface 53 side of the first lens 51, the light shielding material 57 on the emission surface 54 side, and the light shielding material 58 on the incident surface 55 side of the second lens 52 are disposed around each lens element. Each is formed by coating. Then, the thickness of the light shielding material 58 on the incident surface 53 side is made thinner than the thickness of the light shielding material 57 on the emission surface 54 side. For this reason, the diameter of the aperture formed in the light shielding material 58 is formed to be larger than the diameter formed in the light shielding material 57. Further, no light-shielding material is provided in the vicinity of the exit surface 56 of the second lens 52, and the lens elements have a hexagonal outer shape with no gap and are in contact with each other (FIG. 8D). ).

  Therefore, according to the present embodiment, even if the first lens 51 and the second lens 52 are decentered in the main scanning direction and the sub-scanning direction, the light beam is not decentered up to the aperture radius difference. There is an effect that light is not shielded. Further, since the light flux passing through each lens element is narrowed to some extent on the incident surface 53 of the first lens 51, even if there is a certain degree of eccentricity between the two lenses, it is adjacent on the exit surface 56 of the second lens 52. Part of the light beam can be prevented from entering the lens element of the other second lens 52.

<Embodiment 6>
FIG. 9 is a configuration diagram of a lens array used in the present embodiment, FIG. 9A is a top view of the lens array 50, FIG. 9B is a cross-sectional view of the lens array 50 in the sub-scanning direction, FIG. 9C is a sectional view of the lens array 50 in the main scanning direction, and FIG. 9D is a bottom view of the lens array 50.

  As shown in FIGS. 9A to 9D, the lens array 50 in the present embodiment is provided with a light shielding material 61 on the surface of the emission surface 56 of the second lens 52 as compared with the fifth embodiment. Is different. The light shielding material 61 is formed by applying ink around each lens element (lens 56) on the emission surface 56 of the second lens 52, or a sheet-like member, like the light shielding material 60. The one provided with an aperture (hole) is positioned with respect to the emission surface 56 and bonded.

  The diameter of the aperture formed in the light shielding material 58 on the incident surface 55 side of the second lens 52 is larger than the diameter of the aperture formed in the light shielding material 57 on the emission surface 54 side of the first lens 51. Further, the diameter of the aperture formed in the light shielding material 61 on the emission surface 56 side of the second lens 52 is larger than the diameter of the aperture formed in the light shielding material 60 on the incident surface 53 side of the first lens 51.

  Therefore, according to the present embodiment, even if the first lens 51 and the second lens 52 are decentered in the main scanning direction and the sub-scanning direction, the light beam is not decentered up to the aperture radius difference. There is an effect that is not shaded. In addition, since the light beam is narrowed to some extent on the incident surface 53 of the first lens 51, even if there is a certain amount of eccentricity between the two lenses, the other lens 56 adjacent to the exit surface 56 of the second lens 52 is adjacent. Part of the light beam can be prevented from entering.

  Further, since the stray light is also cut by the light shielding material 61, the stray light generated when a part of the light beam enters another lens 56 adjacent to the exit surface 56 of the second lens 52 reaches the image plane. Can be prevented.

<Modification>
Hereinafter, modifications of the above embodiment will be described with reference to the drawings. 10A and 10B are configuration diagrams of a lens array used in a modification of the fifth embodiment. FIG. 10A is a top view of the lens array 50, and FIG. 10B is a sub-scanning direction of the lens array 50. FIG. 10C is a cross-sectional view of the lens array 50 in the main scanning direction. As shown in FIGS. 10A to 10C, as in the fifth embodiment, a light shielding material 62 is provided at the boundary of the lens 53 on the surface of the incident surface 53 of the first lens 51, and further the incident surface. A light shielding material having a slit is provided on the object point side apart from 53. The light shielding material 62 is provided only at the lens element boundary by applying ink in order to cut light incident on the boundary between the lenses 53 of the first lens 51. As described above, also in the case of the lens array 50 arranged in a line, the light shielding material 59 and the light shielding material are provided on the incident surface 53 side of the first lens 51, similarly to the lens array 50 of the two-dimensional array shown in FIG. 62 is provided so that the light incident on the first lens 51 can be appropriately blocked.

  11 is a configuration diagram of a lens array used in a modification of the sixth embodiment. FIG. 11A is a top view of the lens array 50, and FIG. 11B is a sub-scanning direction of the lens array 50. 11C is a cross-sectional view of the lens array 50 in the main scanning direction, and FIG. 11D is a bottom view of the lens array 50. As shown in FIGS. 11A to 11D, similarly to the sixth embodiment, a light shielding material 63 is provided on the surface of the emission surface 56 of the second lens 52 at the boundary of the lens 56. . The light shielding material 63 is provided only at the lens boundary by applying light shielding ink. By providing the light shielding material 63, the light that has entered the lens element 56 of the other second lens 52 adjacent to the light exit surface 56 of the second lens 52 is prevented from traveling in the image plane direction. There is an effect that can be done. Further, in the vicinity of the emission surface 56 of the second lens 52, a light shielding material 64 having a slit is provided in the same manner as the incident surface 53 side of the first lens 51, and the ability to reduce stray light is enhanced. Yes.

  In the present embodiment, the scanner unit 15 as a reading device has been described as a part of the image forming apparatus. However, the present invention is not limited to this, and the scanner unit 15 itself may be defined as an image forming apparatus.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

19 (19Y, 19M, 19C, 19K) ... Scanning heads 20Y, 20M, 20C, 20K ... Image forming units 22Y, 22M, 22C, 22K ... Photosensitive drum (image carrier)
43 ... Light emitting elements 47, 48 ... Illumination device 49 ... Sensor 50 ... Lens array (imaging element array)
DESCRIPTION OF SYMBOLS 51 ... 1st lens 52 ... 2nd lens 53 ... Incident surface 54 of 1st lens ... Output surface 55 of 1st lens ... Incident surface 56 of 2nd lens ... Output surface 57 of 2nd lens, 58, 59, 60, 61, 62, 63, 64 ... light shielding material

Claims (10)

A first lens having a plurality of lens elements arranged in a direction orthogonal to the optical axis and condensing light incident on the incident surface from an object point by the lens elements disposed on the incident surface and the exit surface;
Each lens element formed in the same shape as the first lens and arranged in a direction orthogonal to the optical axis in a state reversed 180 degrees with respect to the first lens, and arranged in the first lens. A second lens having a plurality of lens elements in which an incident surface is disposed downstream of an optical path at a position where the light is collected, and the light incident on the incident surface is again condensed by the output surface;
Apertures corresponding to the lens elements of the first lens and the second lens are formed, arranged at least between the exit surface of the first lens and the entrance surface of the second lens, and enter or exit. A light shielding material that shields light at a portion other than the aperture;
With
The light shielding material is ink applied to the surface of the first lens or the second lens, and the thickness of the ink is changed for each corresponding incident surface and outgoing surface, and the diameter of the aperture is determined. A lens array. The light shielding material comprises a first light shielding material formed on the surface of the exit surface of the first lens and a second light shielding material formed on the surface of the incident surface of the second lens,
The lens array according to claim 1, wherein a diameter of the aperture formed in the second light shielding material is larger than a diameter of the aperture formed in the first light shielding material. The light shielding material includes a first light shielding material formed on a surface of an emission surface of the first lens, a second light shielding material formed on a surface of an incident surface of the second lens, and the first lens. A third light-shielding material formed on the surface of the incident surface of
The lens array according to claim 1, wherein a diameter of the aperture formed in the second light shielding material is larger than a diameter of the aperture formed in the first light shielding material. The light shielding material includes a first light shielding material formed on a surface of an emission surface of the first lens, a second light shielding material formed on a surface of an incident surface of the second lens, and the first lens. A third light-shielding material formed on the surface of the incident surface of
2. The lens array according to claim 1, wherein the third light-shielding material is formed with a slit whose width in the sub-scanning direction changes at a lens array pitch period on the incident surface of the first lens. The light shielding material includes a first light shielding material formed on a surface of an emission surface of the first lens, a second light shielding material formed on a surface of an incident surface of the second lens, and the first lens. A third light-shielding material formed on the surface of the incident surface of
The third light shielding material is
A slit portion whose width in the sub-scanning direction changes at a lens array pitch period on the incident surface of the first lens;
A boundary light shielding unit that shields light incident on the boundary between lens elements disposed on the incident surface of the first lens from the object point;
The lens array according to claim 1, comprising: The light shielding material includes a first light shielding material formed on a surface of an emission surface of the first lens, a second light shielding material formed on a surface of an incident surface of the second lens, and the first lens. A third light-shielding material formed on the surface of the incident surface, and a fourth light-shielding material formed on the surface of the exit surface of the second lens,
The diameter of the aperture formed in the second light shielding material is larger than the diameter of the aperture formed in the first light shielding material, and the diameter of the aperture formed in the fourth light shielding material, or The lens array according to claim 1, wherein the size is larger than a diameter or a size of an aperture formed in the third light shielding material. Sensors arranged in the main scanning direction of the document;
An illumination device that is provided in a main scanning direction of the document and irradiates light on the document surface;
A first lens having a plurality of lens elements arranged in a direction perpendicular to the optical axis and condensing light incident on the incident surface from the document surface by the output surface is formed in the same shape as the first lens. , Downstream of the optical path of the position where light is collected by each lens element arranged in the direction orthogonal to the optical axis in a state of being inverted 180 degrees with respect to the first lens. Corresponding to a lens element combination of the second lens having a plurality of lens elements for concentrating the light incident on the incident surface again by the exit surface, and the lens elements of the first lens and the second lens. And a light-shielding material that is disposed at least between the exit surface of the first lens and the entrance surface of the second lens and shields incident or emitted light at a portion other than the aperture. lens And Ray,
With
The light shielding material is ink applied to the surface of the first lens or the second lens, and the thickness of the ink is changed for each corresponding incident surface and outgoing surface, and the diameter of the aperture is determined. A reader characterized by being provided. A reading device according to claim 7;
An exposure device that irradiates the image carrier with light based on image data generated by the reader and exposes the image carrier;
A developer for supplying a developer to the image carrier and forming a toner image on the image carrier;
An image forming apparatus comprising: A light source that emits light;
A first lens having a plurality of lens elements arranged in a direction perpendicular to the optical axis and condensing the light incident on the incident surface from the light source by the exit surface, and formed in the same shape as the first lens; An optical path of a position where light is collected by each lens element arranged in a direction orthogonal to the optical axis in a state of being inverted 180 degrees with respect to the first lens, and disposed on the plurality of first lenses. Corresponding to a second lens having a plurality of lens elements that have a light incident surface arranged downstream and condense light incident on the light incident surface again by the light emitting surface, and the lens elements of the first lens and the second lens. And a light-shielding material that is disposed at least between the exit surface of the first lens and the entrance surface of the second lens and shields incident or emitted light at a portion other than the aperture. Lentor And stomach,
With
The light shielding material is ink applied to the surface of the first lens or the second lens, and the thickness of the ink is changed for each corresponding incident surface and outgoing surface, and the diameter of the aperture is determined. An exposure apparatus that is characterized in that: An exposure apparatus according to claim 9,
A photoconductor for irradiating light with the exposure apparatus to form an electrostatic latent image;
A developer for supplying a developer to the photoreceptor and forming a toner image on the photoreceptor;
An image forming apparatus comprising:

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