JP2014156023A - Molding die and optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding die capable of equalizing the quality of moldings.SOLUTION: A molding die (8) comprises a cavity piece (3) which has an optical surface non-molding surface (6) at least partially, at least one injection vent hole (14) for blowing a gas (13) toward a resin (10) and at least one discharge vent hole (15) for discharging the gas (13) blown toward the resin (10). When the optical surface non-molding surface (6) of the cavity piece (3) is slid so as to be separated from the resin (10), the gas (13) blown toward the resin (10) from the injection vent hole (15) is discharged through the discharge vent hole (15).

Description

  The present disclosure relates to a technique for molding a molded article.

  2. Description of the Related Art Conventionally, an optical scanning device mounted on an image forming apparatus such as a laser-type digital copying machine, a printer, or a facsimile uses a rectangular optical element having a laser beam imaging and various correction functions. .

  In recent years, optical elements have been changed from glass to plastic due to the demand for product cost reduction. Further, in order to realize a plurality of functions with a minimum number of optical elements, the mirror shape of the optical elements is not only spherical but also a complex aspherical shape, and the optical elements have a special shape. For example, in the case of an optical element such as a lens or a prism, the lens thickness is often designed to be thick, or the lens thickness is often designed to be an uneven thickness.

  The molded product of the above-described optical element is molded by inserting a resin into a cavity of a mold formed in the shape of the molded product or filling a melted resin. Thereby, even if the molded article of the optical element has a special shape, it can be mass-produced at low cost.

  When molding the above molded product, it is preferable that the resin pressure and the resin temperature in the cavity be uniform in the step of cooling and solidifying the molten resin in the mold cavity. Thereby, a molded article can be shape | molded accurately in a desired shape.

  However, for example, when the molded product has a complicated uneven thickness, the volume shrinkage differs depending on the lens thickness portion, so that the shape accuracy of the molded product is deteriorated and sink marks are generated at a portion where the lens thickness is thick. There is a case.

  In order to solve the above problem, it is preferable to increase the injection filling amount by increasing the injection pressure of the molten resin in the injection molding method in which the molten resin is injected and filled into the cavity of the mold. However, when the injection pressure of the molten resin is increased to increase the injection filling amount, the internal distortion of the molded product increases. In particular, when the molded product is thick or uneven, the optical performance may be adversely affected if the internal distortion increases.

  Note that if the injection pressure is lowered to reduce the internal strain and the injection filling amount is reduced, sink marks will occur in the thick part of the molded product.

  For this reason, if the injection pressure of the molten resin is increased to increase the injection filling amount, the internal distortion of the molded product increases, and if the injection pressure is decreased to reduce the injection filling amount, the thick portion of the molded product is exposed. There will be sink marks.

  Therefore, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2000-84945), a concave shape (non-transfer surface) or a convex shape formed by incomplete transfer on a part of the surface other than the transfer surface is provided. A method of providing a molded product is disclosed. As a result, it is possible to obtain a molded product with the same production cost and high shape accuracy even if the molded product has a thick or uneven shape without remaining resin pressure or internal strain. I have to.

  As a specific method of forming a concave shape (non-transfer surface) on a part of the surface other than the transfer surface as in Patent Document 1, for example, Patent Document 2 (Japanese Patent Laid-Open No. 2000-141413), Patent Document 3 (Japanese Patent Laid-Open No. 2000-141425), Japanese Patent Laid-Open No. 11-28745, Japanese Patent Laid-Open No. 2007-30339, Japanese Patent Laid-Open No. 2011-25433, and the like. Is disclosed.

  The methods of Patent Documents 2, 3, and 4 are schematically shown in FIG. FIG. 16 shows a configuration example of a conventional mold 108. A mold 108 shown in FIG. 16 includes a mold insert 101 having an optical surface molding surface 105, a mold insert 102 having a non-optical surface molding surface 106, and a cavity piece 103. The optical surface molding surface 105 is a portion that forms a transfer surface. The non-optical surface molding surface 106 is a portion that forms a non-transfer surface.

  First, as shown in FIG. 16A, a molten resin is injected and filled into a cavity 107 constituted by a mold insert 101, a mold insert 102, and a cavity piece 103, and the resin is cooled to below the softening temperature of the resin. Next, while the resin is being cooled, the cavity piece 103 is moved to separate the non-optical surface molding surface 106 of the cavity piece 103 from the resin 110 as shown in FIG. A gap 109 is forcibly formed between the resin 110 and the resin 110. By forming this gap 109, the cooling of the resin 110 in contact with the non-optical surface molding surface 106 of the cavity piece 103 causes the optical surface molding surface 105 of the mold insert 101, the mold insert 102, and the non-optical surface of the cavity piece 103. Compared to the resin 110 in contact with the molding surface 106, the delay is relatively delayed. As a result, the resin 110 in the cavity 107 contracts as the cooling progresses, but the resin (resin that has not reached below the softening temperature of the resin) 110 in contact with the gap 109 moves and the resin 110 The above shrinkage is absorbed. As a result, sink marks (which may be a concave shape or a convex shape or both) are preferentially generated in a portion in contact with the gap 109.

  In FIG. 16, by intentionally and preferentially inducing sink marks in the portion of the resin 110 that is in contact with the gap 109, it is possible to prevent sink marks from occurring on the transfer surface formed by the optical surface molding surface 105. As a result, the transfer surface is formed with a highly accurate shape. Thereby, it is possible to prevent a decrease in the shape accuracy of the transfer surface due to sink marks. Further, since the injection molding can be performed at a low pressure, the internal strain of the resin 110 can also be reduced.

  Moreover, the method of patent document 5 is shown schematically in FIG. FIG. 17 shows a configuration example of a conventional mold 108. In FIG. 17, a vent 111 and a flow path 112 are provided in the cavity piece 103. Then, the melted resin is injected and filled into the cavity 107 shown in FIG. 17A, and the resin is cooled to below the softening temperature of the resin. Next, while the resin is being cooled, as shown in FIG. 17B, compressed gas 113 (gas such as compressed air, nitrogen, carbon dioxide) is blown from the vent 111 to the resin 110, and the compressed gas. Sinking is forcibly generated on the surface of the resin 110 on which 113 is sprayed.

  In the case of the method shown in FIG. 16, the shrinkage volume of the resin 110 is insufficient only by the natural shrinkage of the resin 110, so that the transfer surface formed by the optical surface molding surface 105 may be sinked. In such a case, as shown in FIG. 17, a method of forcibly generating sink marks by blowing a compressed gas 113 onto the resin 110 is effective.

  Moreover, the method of patent document 6 is shown schematically in FIG. FIG. 18 shows a configuration example of a conventional mold 108. In FIG. 18, an auxiliary vent 114 is provided in the vent 111. And while cooling resin, as shown in FIG. 18, the compressed gas 113 (gas, such as compressed air, nitrogen, a carbon dioxide) is sprayed on resin 110 from the vent 111 and the auxiliary vent 114, The Sinking is forcibly generated on the surface of the resin 110 on which the compressed gas 113 is sprayed. Thereby, it is possible to secure a larger area of the portion where sink marks are generated than the method shown in FIG.

  However, in the method of injecting the compressed gas 113 from the vents 111 and 114 to the resin 110 as in Patent Documents 5 and 6, the resin 110 does not enter from the vents 111 and 114 when the cavity 107 is filled with the resin. It is necessary to do so. For this reason, it is necessary to reduce the opening width of the vent holes 111 and 114 to, for example, about 0.02 mm.

  As a result, due to processing errors or assembly errors in the opening widths of the vent holes 111 and 114, the gas flow rate or pressure changes, and each time the molded product is molded in the cavity 107, a difference occurs in the sink amount of the molded product. . For this reason, the shape of the molded product and the deviation (birefringence index) of the internal distortion are different for each molded product, resulting in a difference in the quality of the molded product.

  In addition, the cooling of the resin 110 can be shortened by continuing to flow the compressed gas 113 from the vent holes 111 and 114 after the occurrence of sink marks in the resin 110. However, in the method of injecting the compressed gas 113 from the vents 111 and 114 to the resin 110 as in Patent Documents 5 and 6, it is necessary to reduce the opening width of the vents 111 and 114. For this reason, the injection amount of the compressed gas 113 is suppressed, and the cooling of the resin 110 cannot be shortened much.

  An object of the present disclosure is to provide a molding die capable of achieving uniform quality of a molded product.

A molding die according to one aspect of the present disclosure is provided.
A cavity for molding a molded product by filling a resin is composed of a plurality of molding surfaces. The plurality of molding surfaces includes an optical surface molding surface for molding an optical surface on the molded product, and the molded product. A molding die having a non-optical surface molding surface for molding a non-optical surface,
A cavity piece having at least a part of the non-optical surface molding surface, at least one injection vent for blowing gas to the resin, and at least one discharge for discharging the gas blown to the resin. A vent, and
When the non-optical surface molding surface of the cavity piece is slid so as to be separated from the resin, the gas blown to the resin from the injection vent is discharged through the discharge vent. It is characterized by that.

  According to one aspect of the present disclosure, the quality of a molded product can be made uniform.

1 is a diagram illustrating a schematic configuration example of an image forming apparatus 2000 of the present embodiment. 1 is a first diagram illustrating a schematic configuration of an optical scanning device 2010. FIG. 2 is a second diagram illustrating a schematic configuration of an optical scanning device 2010. FIG. 6 is a third diagram illustrating a schematic configuration of an optical scanning device 2010. FIG. 6 is a fourth diagram illustrating a schematic configuration of the optical scanning device 2010. FIG. It is a figure for demonstrating the deflector side scanning lens 2105c. It is a figure which shows the structural example of the metal mold | die 8 for shape | molding the molded article of the deflector side scanning lens 2105c. It is a figure which shows the cross-sectional structural example of AA of the metal mold | die 8 shown in FIG. It is a figure which shows the cross-sectional structural example of 50-50 of the metal mold | die 8 shown to Fig.8 (a). (A) is a figure which shows the cross-sectional structural example of 51-51 of the metal mold | die 8 shown to Fig.8 (a), (b) is the cross section of 52-52 of the metal mold | die 8 shown to Fig.8 (a). It is a figure which shows the example of a structure. It is a 1st figure which shows the other structural example of the metal mold | die 8 shown to Fig.8 (a). It is the 2nd figure which shows the other structural example of the metal mold | die 8 shown to Fig.8 (a). It is the 3rd figure which shows the other structural example of the metal mold | die 8 shown to Fig.8 (a). It is the 4th figure which shows the other structural example of the metal mold | die 8 shown to Fig.8 (a). It is a 5th figure which shows the other structural example of the metal mold | die 8 shown to Fig.8 (a). It is a 1st figure which shows the structural example of the conventional metal mold | die 108. FIG. It is a 2nd figure which shows the structural example of the conventional metal mold | die 108. FIG. It is a 3rd figure which shows the structural example of the conventional metal mold | die 108. FIG.

(Outline of Embodiment of Molding Mold 8 According to One Aspect of the Present Disclosure)
First, an overview of an embodiment of a molding die 8 according to one aspect of the present disclosure will be described with reference to FIG. FIG. 8 is a diagram illustrating a configuration example of the molding die 8 according to one aspect of the present disclosure.

  In the molding die 8 according to an aspect of the present disclosure, a cavity 7 for filling a resin 10 and molding a molded product is configured by a plurality of molding surfaces 5 and 6. The plurality of molding surfaces 5 and 6 include an optical surface molding surface 5 that molds an optical surface on a molded product and a non-optical surface molding surface 6 that molds a non-optical surface on the molded product.

  The molding die 8 according to one aspect of the present disclosure includes the cavity piece 3, at least one injection vent 14, and at least one discharge vent 15. The cavity piece 3 is a movable cavity and has at least a part of the non-optical surface molding surface 6. The injection vent 14 is a vent for blowing the gas 13 on the resin 10. The discharge vent 15 is a vent for discharging the gas 13 sprayed on the resin 10.

  When the non-optical surface molding surface 6 of the cavity piece 3 is slid so as to be separated from the resin 10, the molding die 8 according to one aspect of the present disclosure is sprayed from the injection vent 14 to the resin 10. The gas 13 is exhausted through the exhaust vent 15.

  In the molding die 8 according to one aspect of the present disclosure, the injection vent 14 and the discharge vent 15 are provided at locations that do not contact the optical surface molding surface 5 that forms the optical surface. For this reason, it can suppress applying the big pressure by the gas 13 to a molded article. As a result, even if a gas flow rate or pressure change occurs due to a slight processing error or assembly error of the injection vent 14 and the discharge vent 15, the influence of the change on the molded product can be suppressed. Therefore, it is possible to suppress the deterioration of the shape of the optical surface and internal distortion of the molded product, and to mold a molded product having the same quality, and to uniform the quality of the molded product. Hereinafter, embodiments of the molding die 8 according to one aspect of the present disclosure will be described in detail with reference to the accompanying drawings.

<Configuration Example of Image Forming Apparatus 2000>
First, a configuration example of the image forming apparatus 2000 of the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a schematic configuration example of an image forming apparatus 2000 according to the present embodiment.

  The image forming apparatus 2000 of this embodiment is a tandem multicolor printer that forms a full color image by superimposing four colors (black, cyan, magenta, and yellow).

  The image forming apparatus 2000 of this embodiment includes an optical scanning device 2010, four photosensitive drums (2030a, 2030b, 2030c, 2030d), four cleaning units (2031a, 2031b, 2031c, 2031d), and four charging devices (2032a). , 2032b, 2032c, 2032d), four developing rollers (2033a, 2033b, 2033c, 2033d), four toner cartridges (2034a, 2034b, 2034c, 2034d), transfer belt 2040, transfer roller 2042, fixing roller 2050, paper feed A roller 2054, a pair of registration rollers 2056, a paper discharge roller 2058, a paper feed tray 2060, a paper discharge tray 2070, a communication control device 2080, and a printer control device 2090 that controls each of the above-described units are provided.

  In the present embodiment, in the XYZ three-dimensional orthogonal coordinate system, the direction along the longitudinal direction of each photosensitive drum is described as the Y-axis direction, and the direction along the arrangement direction of the four photosensitive drums is described as the X-axis direction.

  The communication control device 2080 controls bidirectional communication with a host device (for example, a personal computer) via a network or the like and an information device (for example, a facsimile device) via a public line. Then, the communication control device 2080 notifies the received information to the printer control device 2090.

  The printer control device 2090 includes a CPU, a ROM described in a program written in code readable by the CPU, various data used when executing the program, a RAM as a working memory, an analog data An AD converter for converting the signal into digital data. The printer control device 2090 controls each unit in response to requests from the host device and the information device, and sends image information from the host device and the information device to the optical scanning device 2010.

  The photosensitive drum 2030a, the charging device 2032a, the developing roller 2033a, the toner cartridge 2034a, and the cleaning unit 2031a are used as a set. The set constitutes an image forming station (hereinafter also referred to as “K station” for convenience) that forms a black image.

  The photosensitive drum 2030b, the charging device 2032b, the developing roller 2033b, the toner cartridge 2034b, and the cleaning unit 2031b are used as a set. The set constitutes an image forming station (hereinafter also referred to as “C station” for convenience) for forming a cyan image.

  The photosensitive drum 2030c, the charging device 2032c, the developing roller 2033c, the toner cartridge 2034c, and the cleaning unit 2031c are used as a set. The set constitutes an image forming station for forming a magenta image (hereinafter also referred to as “M station” for convenience).

  The photosensitive drum 2030d, the charging device 2032d, the developing roller 2033d, the toner cartridge 2034d, and the cleaning unit 2031d are used as a set. The set constitutes an image forming station (hereinafter also referred to as “Y station” for convenience) for forming a yellow image.

  Each photosensitive drum has a photosensitive layer formed on the surface thereof. That is, the surface of each photoconductive drum is a surface to be scanned. Each photosensitive drum is rotated in the direction of the arrow in the plane of FIG. 1 by a rotation mechanism (not shown).

  Each charging device uniformly charges the surface of the corresponding photosensitive drum.

  The optical scanning device 2010 uses the multi-color image information (black image information, cyan image information, magenta image information, yellow image information) from the printer control device 2090 to charge the light flux modulated for each color to the corresponding charging. Irradiate each of the surfaces of the photosensitive drums. As a result, on the surface of each photoconductive drum, the charge disappears only in the portion irradiated with light, and a latent image corresponding to the image information is formed on the surface of each photoconductive drum. The latent image formed here moves in the direction of the corresponding developing roller as the photosensitive drum rotates. The configuration of the optical scanning device 2010 will be described later.

  The toner cartridge 2034a stores black toner, and the toner is supplied to the developing roller 2033a. The toner cartridge 2034b stores cyan toner, and the toner is supplied to the developing roller 2033b. The toner cartridge 2034c stores magenta toner, and the toner is supplied to the developing roller 2033c. The toner cartridge 2034d stores yellow toner, and the toner is supplied to the developing roller 2033d.

  As each developing roller rotates, the toner from the corresponding toner cartridge is thinly and uniformly applied to the surface thereof. Then, when the toner on the surface of each developing roller comes into contact with the surface of the corresponding photosensitive drum, the toner moves only to a portion irradiated with light on the surface and adheres to the surface. In other words, each developing roller causes toner to adhere to the latent image formed on the surface of the corresponding photosensitive drum to make it visible. Here, the toner-attached image (toner image) moves in the direction of the transfer belt 2040 as the photosensitive drum rotates.

  The yellow, magenta, cyan, and black toner images are sequentially transferred onto the transfer belt 2040 at a predetermined timing, and are superimposed to form a multicolor image.

  Recording paper is stored in the paper feed tray 2060. A paper feed roller 2054 is disposed in the vicinity of the paper feed tray 2060, and the paper feed roller 2054 takes out recording sheets one by one from the paper feed tray 2060 and conveys them to a pair of registration rollers 2056. The registration roller pair 2056 feeds the recording paper toward the gap between the transfer belt 2040 and the transfer roller 2042 at a predetermined timing. As a result, the color image on the transfer belt 2040 is transferred to the recording paper. The recording sheet transferred here is sent to the fixing roller 2050.

  In the fixing roller 2050, heat and pressure are applied to the recording paper, whereby the toner is fixed on the recording paper. The recording paper fixed here is sent to a paper discharge tray 2070 via a paper discharge roller 2058 and is sequentially stacked on the paper discharge tray 2070.

  Each cleaning unit removes toner (residual toner) remaining on the surface of the corresponding photosensitive drum. The surface of the photosensitive drum from which the residual toner has been removed returns to the position facing the corresponding charging device again.

<Configuration Example of Optical Scanning Device 2010>
Next, a configuration example of the optical scanning device 2010 will be described with reference to FIGS. 2 to 5 are diagrams illustrating configuration examples of the optical scanning device 2010. FIG.

  2 to 5 as an example, the optical scanning device 2010 includes four light sources (2200a, 2200b, 2200c, 2200d), four coupling lenses (2201a, 2201b, 2201c, 2201d), four openings. Plate (2202a, 2202b, 2202c, 2202d), 4 cylindrical lenses (2204a, 2204b, 2204c, 2204d), polygon mirror 2104, 4 deflector side scanning lenses (2105a, 2105b, 2105c, 2105d), 8 foldings Mirrors (2106a, 2106b, 2106c, 2106d, 2108a, 2108b, 2108c, 2108d), four image plane side scanning lenses (2107a, 2107b, 2107c, 2107d), four light detection sensors (2205a, 205b, 2205c, 2205d), 4 sheets of light detection mirror (2207a, includes 2207b, 2207c, 2207d), and the like scanning control device (not shown). These are assembled at predetermined positions of the optical housing 2300 (not shown in FIGS. 2 to 4, see FIG. 5).

  In the following, for convenience, the direction corresponding to the main scanning direction is abbreviated as “main scanning corresponding direction”, and the direction corresponding to the sub scanning direction is abbreviated as “sub scanning corresponding direction”.

  The light source 2200b and the light source 2200c are disposed at positions separated from each other in the X-axis direction. The light source 2200a is disposed on the −Z side of the light source 2200b. The light source 2200d is arranged on the −Z side of the light source 2200c.

  The coupling lens 2201a is disposed on the optical path of the light beam emitted from the light source 2200a, and makes the light beam a substantially parallel light beam.

  The coupling lens 2201b is disposed on the optical path of the light beam emitted from the light source 2200b, and makes the light beam a substantially parallel light beam.

  The coupling lens 2201c is disposed on the optical path of the light beam emitted from the light source 2200c, and makes the light beam a substantially parallel light beam.

  The coupling lens 2201d is disposed on the optical path of the light beam emitted from the light source 2200d, and makes the light beam a substantially parallel light beam.

  The aperture plate 2202a has an aperture and shapes the light beam that has passed through the coupling lens 2201a.

  The aperture plate 2202b has an aperture and shapes the light beam that has passed through the coupling lens 2201b.

  The aperture plate 2202c has an aperture and shapes the light beam that has passed through the coupling lens 2201c.

  The aperture plate 2202d has an aperture and shapes the light beam that has passed through the coupling lens 2201d.

  The cylindrical lens 2204 a forms an image of the light beam that has passed through the opening of the aperture plate 2202 a in the vicinity of the deflection reflection surface of the polygon mirror 2104 in the Z-axis direction.

  The cylindrical lens 2204b forms an image of the light beam that has passed through the opening of the aperture plate 2202b in the vicinity of the deflection reflection surface of the polygon mirror 2104 in the Z-axis direction.

  The cylindrical lens 2204 c forms an image of the light beam that has passed through the opening of the aperture plate 2202 c in the vicinity of the deflection reflection surface of the polygon mirror 2104 in the Z-axis direction.

  The cylindrical lens 2204d forms an image of the light flux that has passed through the opening of the aperture plate 2202d in the vicinity of the deflection reflection surface of the polygon mirror 2104 in the Z-axis direction.

  The polygon mirror 2104 has a four-stage mirror having a two-stage structure, and each mirror serves as a deflection reflection surface. In the first (lower) four-sided mirror, the light beam from the cylindrical lens 2204a and the light beam from the cylindrical lens 2204d are respectively deflected. Further, in the second stage (upper stage) four-sided mirror, the light beam from the cylindrical lens 2204b and the light beam from the cylindrical lens 2204c are respectively deflected.

  Here, the light beams from the cylindrical lens 2204 a and the cylindrical lens 2204 b are deflected to the −X side of the polygon mirror 2104. Further, the light beams from the cylindrical lens 2204 c and the cylindrical lens 2204 d are deflected to the + X side of the polygon mirror 2104.

  Each deflector-side scanning lens has a non-circular surface shape having such a power that the light spot moves at a constant speed in the main scanning direction on the corresponding photosensitive drum surface as the polygon mirror 2104 rotates. ing.

  The deflector side scanning lens 2105a and the deflector side scanning lens 2105b are arranged on the −X side of the polygon mirror 2104, and the deflector side scanning lens 2105c and the deflector side scanning lens 2105d are arranged on the + X side of the polygon mirror 2104. ing.

  The deflector-side scanning lens 2105a and the deflector-side scanning lens 2105b are stacked in the Z-axis direction, the deflector-side scanning lens 2105a is opposed to the first-stage four-sided mirror, and the deflector-side scanning lens 2105b is two-stage. It faces the four-sided mirror of the eye. The deflector-side scanning lens 2105c and the deflector-side scanning lens 2105d are stacked in the Z-axis direction, the deflector-side scanning lens 2105c is opposed to the second-stage four-sided mirror, and the deflector-side scanning lens 2105d is one stage. It faces the four-sided mirror of the eye.

  The light beam from the cylindrical lens 2204a deflected by the polygon mirror 2104 is applied to the photosensitive drum 2030a through the deflector side scanning lens 2105a, the folding mirror 2106a, the image plane side scanning lens 2107a, and the folding mirror 2108a. As a result, a light spot is formed on the photosensitive drum 2030a. This light spot moves in the longitudinal direction of the photosensitive drum 2030a as the polygon mirror 2104 rotates. That is, the photosensitive drum 2030a is scanned. The moving direction of the light spot at this time is the “main scanning direction” on the photosensitive drum 2030a, and the rotational direction of the photosensitive drum 2030a is the “sub-scanning direction” on the photosensitive drum 2030a.

  The light beam from the cylindrical lens 2204b deflected by the polygon mirror 2104 is irradiated onto the photosensitive drum 2030b via the deflector-side scanning lens 2105b, the folding mirror 2106b, the image plane-side scanning lens 2107b, and the folding mirror 2108b. The As a result, a light spot is formed on the photosensitive drum 2030b. This light spot moves in the longitudinal direction of the photosensitive drum 2030b as the polygon mirror 2104 rotates. That is, the photosensitive drum 2030b is scanned. The moving direction of the light spot at this time is the “main scanning direction” on the photosensitive drum 2030b, and the rotational direction of the photosensitive drum 2030b is the “sub-scanning direction” on the photosensitive drum 2030b.

  The light beam from the cylindrical lens 2204c deflected by the polygon mirror 2104 is irradiated onto the photosensitive drum 2030c via the deflector-side scanning lens 2105c, the folding mirror 2106c, the image plane-side scanning lens 2107c, and the folding mirror 2108c. The As a result, a light spot is formed on the photosensitive drum 2030c. This light spot moves in the longitudinal direction of the photosensitive drum 2030c as the polygon mirror 2104 rotates. That is, the photosensitive drum 2030c is scanned. The moving direction of the light spot at this time is the “main scanning direction” on the photosensitive drum 2030c, and the rotational direction of the photosensitive drum 2030c is the “sub-scanning direction” on the photosensitive drum 2030c.

  The light beam from the cylindrical lens 2204d deflected by the polygon mirror 2104 is irradiated onto the photosensitive drum 2030d via the deflector-side scanning lens 2105d, the folding mirror 2106d, the image plane-side scanning lens 2107d, and the folding mirror 2108d. The As a result, a light spot is formed on the photosensitive drum 2030d. This light spot moves in the longitudinal direction of the photosensitive drum 2030d as the polygon mirror 2104 rotates. That is, the photosensitive drum 2030d is scanned. The moving direction of the light spot at this time is the “main scanning direction” on the photosensitive drum 2030d, and the rotational direction of the photosensitive drum 2030d is the “sub-scanning direction” on the photosensitive drum 2030d.

  Incidentally, a scanning area in the main scanning direction in which image information is written on each photosensitive drum is called an “effective scanning area”, an “image forming area”, or an “effective image area”.

  An optical system disposed on the optical path between the polygon mirror 2104 and each photosensitive drum is also called a scanning optical system. In this embodiment, the K station scanning optical system is composed of the deflector side scanning lens 2105a, the image plane side scanning lens 2107a, and the two folding mirrors (2106a, 2108a). The C-station scanning optical system is composed of the deflector-side scanning lens 2105b, the image plane-side scanning lens 2107b, and the two folding mirrors (2106b, 2108b). The M-station scanning optical system is composed of the deflector-side scanning lens 2105c, the image plane-side scanning lens 2107c, and the two folding mirrors (2106c and 2108c). Further, the Y-station scanning optical system is composed of the deflector-side scanning lens 2105d, the image plane-side scanning lens 2107d, and the two folding mirrors (2106d, 2108d).

  A part of the light beam before the start of writing out of the light beam deflected by the polygon mirror 2104 and passed through the scanning optical system of the K station enters the light detection sensor 2205a via the light detection mirror 2207a.

  The light detection sensor 2205b is deflected by the polygon mirror 2104, and a part of the light beam before starting writing out of the light beam via the scanning optical system of the C station enters through the light detection mirror 2207b.

  The light detection sensor 2205c is deflected by the polygon mirror 2104, and a part of the light beam before starting writing out of the light beam via the scanning optical system of the M station enters through the light detection mirror 2207c.

  A part of the light beam before the start of writing out of the light beam deflected by the polygon mirror 2104 and passed through the scanning optical system of the Y station enters the light detection sensor 2205d via the light detection mirror 2207d.

  Each of the light detection sensors outputs a signal (photoelectric conversion signal) corresponding to the amount of received light.

  The scanning control device detects the scanning start timing on the corresponding photosensitive drum based on the output signal of each light detection sensor.

  Each deflector-side scanning lens is a resin optical element that is injection-molded using a mold having the same shape. Therefore, hereinafter, the deflector-side scanning lens 2105c will be described as a representative. Hereinafter, the deflector-side scanning lens 2105c will be described with reference to FIG.

  As the resin constituting the deflector-side scanning lens 2105c, polymethyl methacrylate, polycarbonate, polystyrene, amorphous polyolefin, cycloolefin copolymer, or the like can be used.

  As shown in FIG. 6, the deflector-side scanning lens 2105 c includes a main body having two optical surfaces (an incident-side optical surface and an emission-side optical surface), a rib that reinforces the main body, an attachment reference portion, and the like. It is composed of In the following, for convenience, the optical surface on the incident side is abbreviated as “incident optical surface”, and the optical surface on the emission side is abbreviated as “emitted optical surface”. The + Z side surface of the deflector-side scanning lens 2105c is also referred to as “side surface R”, and the −Z side surface is also referred to as “side surface L”.

  Here, the length of each optical surface in the short direction is 6 mm, and an area having a width of 4 mm at the center is an effective area. The length in the longitudinal direction of each optical surface is 100 mm. And the main-body part has the uneven thickness shape whose thickness of a center part is 10 mm and whose end part is 5 mm.

  The rib is provided at the + Z side end and the −Z side end of each optical surface, and has a width of 2 mm and a height of 2 mm from the optical surface.

  Three attachment reference portions are provided on the + Z-side rib at different positions in the Y-axis direction.

<Configuration example of mold 8>
The deflector-side scanning lens 2105c shown in FIG. 6 can be molded using the mold 8 shown in FIGS. Hereinafter, the mold 8 for molding a molded product of the deflector-side scanning lens 2105c will be described with reference to FIGS. 7-10 is a figure which shows the structural example of the metal mold | die 8 which shape | molds the molded article of the deflector side scanning lens 2105c. FIG. 7 shows an example of the overall configuration of the mold 8. FIG. 8 shows a cross-sectional configuration example of the AA mold 8 shown in FIG. FIG. 9 shows an example of a cross-sectional configuration of the 50-50 mold 8 shown in FIG. FIG. 10 shows a cross-sectional configuration example of the mold 8 of 51-51 shown in FIG.

  The mold 8 of this embodiment is filled with a resin material, and a cavity 7 for forming the above-described molded product of the deflector-side scanning lens 2105c is defined by a plurality of optical surface molding surfaces 5 and non-optical surface molding surfaces 6. It is made up.

  As shown in FIG. 8, the mold 8 of this embodiment includes mold inserts 1 and 1 each having an optical surface molding surface 5 for forming an optical surface on a molded product by transfer, and a non-optical surface on the molded product by transfer. The mold inserts 2 and 2 and the cavity piece 3 each having a non-optical surface molding surface 6 to be molded are configured. The mold inserts 1 and 2 are each composed of one or a plurality of mold parts.

  In the mold 8 of this embodiment, as shown in FIG. 7, an introduction port 20 for introducing the compressed gas 13 into the cavity 7 is provided in at least one of the mold inserts 2 and 2. . Further, an injection vent 14 for blowing the compressed gas 13 from the introduction port 20 onto the resin 10 in the cavity 7 is provided. Further, a discharge vent 15 for discharging the compressed gas 13 sprayed on the resin 10 from the mold 8 is provided.

  The molten resin injected into the mold 8 is injected and filled through the gate 21. Note that a plurality of mold inserts 1 and 2 may be provided in a pair of molds 8 so that a plurality of cavities are defined.

  In the mold 8 of the present embodiment, as shown in FIG. 8, the injection vent 14 and the discharge vent 15 are provided at positions in contact with the slidable cavity piece 3. Thus, when the resin 7 is filled in the cavity 7, the injection vent 14 and the discharge vent 15 are blocked by the cavity piece 3 as shown in FIG. . For this reason, it is possible to prevent the resin filled in the cavity 7 from entering the injection vent 14 and the discharge vent 15. Therefore, the size of the vents of the jet vent 14 and the exhaust vent 15 can be arbitrarily set.

  And after the fluidity | liquidity of the resin 10 falls, as shown in FIG.8 (b), the cavity piece 3 slides and the space | gap 9 is formed between the cavity piece 3 and the resin 10, and it is for injection. The vent 14 and the exhaust vent 15 are opened. Then, the compressed gas 13 can be blown onto the resin 10 through the opened injection vent 14 and discharge vent 15 to promote cooling of the resin 10.

  Further, as shown in FIG. 9, the mold 8 of the present embodiment is provided with a plurality of injection vents 14 and discharge vents 15. FIG. 9 shows a configuration example of a cross section of the mold 50-50 shown in FIG.

  As shown in FIG. 9, the mold 8 according to the present embodiment has the same number of injection vents 14 and the same number of discharge vents 15, and includes the injection vents 14 and the discharge vents 15. The pair of vents are on the same axis. Since the pair of vent holes are on the same axis, the compressed gas 13 can easily flow through the pair of vent holes. As a result, the compressed gas 13 injected into the mold 8 from the injection vent 14 can be easily discharged from the discharge vent 15. It is preferable that the central axis of the opening of the injection vent 14 and the central axis of the opening of the discharge vent 15 are located on the same axis. Thereby, since a pair of vent hole which consists of the vent hole 14 for injection and the vent hole 15 for discharge | emission is connected and comprised, the compressed gas 13 can be made to flow most easily. The opening portion of the injection vent 14 and the opening portion of the discharge vent 15 mean portions constituting the side in contact with the cavity piece 3.

  Further, in the mold 8 of the present embodiment, all the pairs of vent shafts shown in FIG. 9 described above are provided at positions parallel to the non-optical surface molding surface 6 as shown in FIG. preferable. The non-optical surface molding surface 6 is the non-optical surface molding surface 6 of the cavity piece 3 on the side where the injection vent 14 and the discharge vent 15 are formed. Thereby, the pressure of the compressed gas 13 toward the cavity 7 can be prevented from becoming excessive. Note that the central axis of the opening of the injection vent 14 and the central axis of the opening of the discharge vent 15 need only be parallel to the non-optical surface molding surface 6, and the other axes are It does not have to be parallel to the optical surface molding surface 6.

  Further, in the mold 8 of this embodiment, the opening cross-sectional areas of the injection vent 14 and the discharge vent 15 located on the same axis as shown in FIG. 9 are as shown in FIGS. 10 (a) and 10 (b). Is the same. FIG. 10A shows a cross-sectional configuration example of the mold 8 of 51-51 shown in FIG. 8A, and shows the cross-sectional shape of the injection vent 14. FIG. FIG. 10B shows a cross-sectional configuration example of the mold 8 of 52-52 shown in FIG. 8A, and shows a cross-sectional shape of the discharge vent 15.

  By making the opening cross-sectional areas of the injection vent 14 and the discharge vent 15 located on the same axis as shown in FIG. 9 the same, the compressed gas 13 can flow without stagnation. As a result, it is possible to suppress application of a large pressure due to the compressed gas 13 to the molded product, and even if a gas flow rate or pressure change occurs due to slight processing errors or assembly errors of the vent holes 14 and 15, the change is molded. The effect on the product can be suppressed. Thereby, the deterioration of the shape of the optical surface of a molded article and internal distortion can be suppressed. The optical surface of the molded product is formed by the optical surface molding surface 5.

  10A and 10B, the cross-sectional area of the vents 14 and 15 located at the center of the mold 8 is large, and the vents 14 and 15 located at both ends of the mold 8 are The cross-sectional area is small. For example, when the center part of the molded product as shown in FIG. 6 has a thick shape, the shape of the cavity piece 3 in the portion in contact with the resin 10 constituting the thick shape is also formed in a wide shape. For this reason, it is preferable to enlarge the cross-sectional area of the vent holes 14 and 15 located in the center. Thereby, cooling of the resin of the part which comprises the molded product of the thick shape which is hard to cool can be accelerated | stimulated.

  It should be noted that the compressed gas 13 as described above can be obtained by making the total opening area of the injection vent 14 shown in FIG. 10A and the total opening area of the discharge vent 15 shown in FIG. Can flow without delay. The total opening area means the total area of the cross-sectional areas of all the vents.

<Example of molding method of optical element>
Next, an example of a method for molding an optical element using the mold 8 shown in FIGS. 7 to 10 will be described.

  First, the mold 8 having the configuration shown in FIG. 7 is set in an injection molding machine, and the cavity 7 is configured by a plurality of molding surfaces 5 and 6 as shown in FIG. Then, the mold 8 is heated and held at a temperature lower than the melting temperature of the resin used. Next, the molten resin heated to the softening temperature or higher by an injection molding machine is injected from the gate 21 into the cavity 7 and filled. At this time, the molten resin is applied with pressure sufficient for transfer molding by the injection pressure, and is in close contact with the molding surfaces 5 and 6 constituting the cavity 7. At this time, in the mold 8 of this embodiment, the injection vent 14 and the discharge vent 15 are closed by the cavity piece 3 as shown in FIG. For this reason, it is possible to prevent the resin filled in the cavity 7 from entering the injection vent 14 and the discharge vent 15. Thereafter, the resin 10 introduced into the cavity 7 is cooled to a softening temperature or lower and solidified.

  Next, after the fluidity of the resin 10 is lowered, as shown in FIG. 8B, the cavity piece 3 is slid to open the injection vent 14 and the discharge vent 15. The compressed gas 13 (for example, air, nitrogen, carbon dioxide, etc.) is blown onto the resin 10 through the opened injection vent 14 and discharge vent 15. When the compressed gas 13 is blown into the mold 8 from the injection vent 14, the portion of the resin 10 in contact with the compressed gas 13 is cooled, and sinking is intentionally and preferentially generated in that portion. Can do. Thereby, sink marks can be prevented from occurring on the optical surface of the optical element formed by the optical surface molding surface 5. As a result, the optical surface of the optical element is formed with a highly accurate shape. Thereby, the fall of the shape accuracy of the optical surface by sink marks can be prevented. Moreover, since the injection molding can be performed at a low pressure, the internal strain of the resin 10 can also be reduced.

  Next, the solidified resin 10 is taken out from the mold 8 and allowed to cool at room temperature. Thereby, the optical element of the same quality can be shape | molded.

  In the present embodiment, the method for flowing the compressed gas 13 into the mold 8 is not particularly limited, and it is possible to flow in an arbitrary method. For example, it is possible to control so that the compressed gas 13 flows into the mold 8 through the injection vent 14 after the cavity piece 3 slides and the injection vent 14 and the discharge vent 15 are opened. It is. In this case, it is necessary to control the compressed gas 13 to flow into the mold 8 after the injection vent 14 and the discharge vent 15 are opened in conjunction with the sliding of the cavity piece 3. It is also possible to control the compressed gas 13 to flow into the mold 8 even when the injection vent 14 and the discharge vent 15 are closed by the cavity piece 3. In this case, in order to prevent excessive gas pressure from being applied to the cavity piece 3, it is necessary to provide a through hole for connecting the injection vent 14 and the discharge vent 15 in the cavity piece 3. By providing a through hole in the cavity piece 3, the compressed gas 13 that has flowed into the mold 8 from the injection vent 14 is guided to the discharge vent 15 through the through hole, and the mold 8 is discharged from the discharge vent 15. Can be discharged outside.

  In addition, the compressed gas 13 can also use the gas of normal temperature (for example, 23 degreeC). Further, “below the resin temperature” means a temperature at which the resin 10 can be cooled regardless of the state of the resin 10. That is, there is no problem at a temperature lower than the glass transition temperature in the molten state, but when the resin 10 is in a cured state due to cooling, it is necessary to flow the compressed gas 13 below the temperature of the cured resin 10. Usually, it is preferable to flow the compressed gas 13 at a temperature lower than the temperature of taking out the molded product (normal temperature or the like) from the beginning without dividing into cases.

<Operation / Effect of Mold 8 of this Embodiment>
As described above, in the mold 8 of the present embodiment, the injection vent 14 and the discharge vent 15 are provided at positions in contact with the slidable cavity piece 3. Then, as shown in FIG. 8A, when the cavity 7 is configured and filled with the resin 10, the injection vent 14 and the discharge vent 15 are blocked by the cavity piece 3. Further, as shown in FIG. 8B, when the cavity piece 3 slides, the injection vent 14 and the discharge vent 15 are opened. Then, the compressed gas 13 is poured through the opened injection vent 14 to promote cooling of the resin 10.

  In the mold 8 of this embodiment, when the cavity 7 is formed and the resin 10 is filled, the injection vent 14 and the discharge vent 15 are closed by the cavity piece 3. Therefore, the resin 10 filled in the cavity 7 can be prevented from entering the injection vent 14 and the discharge vent 15. As a result, the size of the vents of the jet vent 14 and the discharge vent 15 can be arbitrarily set. That is, as shown in FIG. 11, the area of the openings of the injection vent 14 and the discharge vent 15 can be increased to improve the cooling efficiency, and the molding of the molded product can be shortened. Therefore, the molding cost of the molded product can be reduced.

  Further, by providing the injection vent 14 and the discharge vent 15 at a location not in contact with the optical surface molding surface 5 that forms the optical surface, it is possible to suppress applying a large pressure by the compressed gas 13 to the molded product. it can. As a result, even if a gas flow rate or pressure change occurs due to a slight processing error or assembly error of the injection vent 14 and the discharge vent 15, the influence of the change on the molded product can be suppressed. Therefore, the deterioration of the shape of the optical surface of the molded product and internal distortion can be suppressed, and a molded product having the same quality can be molded.

  Note that the mold 8 of the above-described embodiment is provided with the ejection vent 14 and the discharge vent 15 in the short direction of the optical element, as shown in FIG. However, as shown in FIG. 12, it is also possible to provide the ejection vent 14 and the discharge vent 15 in the longitudinal direction of the optical element. FIG. 12 is a diagram illustrating a cross-sectional configuration example of a portion corresponding to 53-53 of the mold 8 illustrated in FIG. Even in the configuration shown in FIG. 12, the injection vent 14 and the discharge vent 15 are blocked by the cavity piece 3 when the cavity 7 is configured and the resin 10 is filled, as in the above-described embodiment. It is trying to be. Therefore, the resin 10 filled in the cavity 7 can be prevented from entering the injection vent 14 and the discharge vent 15. As a result, the size of the vents of the jet vent 14 and the discharge vent 15 can be arbitrarily set. That is, the area of the opening of the vent can be increased to improve the cooling efficiency, and the molding of the molded product can be shortened. Therefore, the molding cost of the molded product can be reduced. Further, by providing the injection vent 14 and the discharge vent 15 at a location not in contact with the optical surface molding surface 5 that forms the optical surface, it is possible to suppress applying a large pressure by the compressed gas 13 to the molded product. it can. As a result, even if a gas flow rate or pressure change occurs due to a slight processing error or assembly error of the injection vent 14 and the discharge vent 15, the influence of the change on the molded product can be suppressed. Therefore, the deterioration of the shape of the optical surface of the molded product and internal distortion can be suppressed, and a molded product having the same quality can be molded. In addition, due to structural limitations of the mold 8, as shown in FIG. 8A, there may be a case where the injection vent 14 and the discharge vent 15 cannot be provided in the short direction of the optical element. In this case, as shown in FIG. 12, an injection vent 14 and a discharge vent 15 may be provided in the longitudinal direction of the optical element.

  In addition, as shown in FIG. 13, the mold 8 according to the above-described embodiment is provided with a curved surface 16 at the opening of the injection vent 14, and the compressed gas 13 is introduced from the opening of the injection vent 14 toward the resin 10. It is also possible to make it easier to enter. It is also possible to provide a curved surface 16 at the opening of the discharge vent 15 so that the compressed gas 13 can easily flow out of the opening of the discharge vent 15 to the discharge vent 15 side. Although the curved surface 16 is provided in FIG. 13, the curved surface 16 is not limited, and a tapered shape may be provided. In other words, the shape of the opening is not particularly limited as long as the area of the opening of the injection vent 14 can be configured to be larger than the cross-sectional area other than the opening of the injection vent 14. Can be configured. The shape of the opening is not particularly limited as long as the area of the opening of the discharge vent 15 can be configured to be larger than the cross-sectional area other than the opening of the discharge vent 15. Can be configured. The area of the opening of the injection vent 14 is larger than the cross-sectional area other than the opening of the injection vent 14, and the area of the opening of the discharge vent 15 is a cross-sectional area other than the opening of the discharge vent 15. By making it larger than that, the compressed gas 13 can generate a flow toward the molded product. As a result, the compressed gas 13 injected from the injection vent 14 can be prevented from being discharged as it is to the discharge vent 15 and the cooling efficiency of the molded product can be improved.

  Further, as shown in FIG. 8B, the mold 8 of the above-described embodiment slides the cavity piece 3 and opens the injection vent 14 and the discharge vent 15. In this case, when sliding the cavity piece 3, the resin 10 may be pulled on the non-optical surface molding surface 6 of the cavity piece 3. In order to avoid this point, as shown in FIG. 14, the cavity piece 3 is provided with a flow path 12 and a vent 11, and the compressed gas 13 that has flowed in from the injection vent 14 is passed through the flow path 12 and the vent 11. It is preferable that the resin 10 is sprayed. Thereby, it is possible to prevent the resin 10 from being pulled by the non-optical surface molding surface 6 of the cavity piece 3 when sliding the cavity piece 3. After sliding the cavity piece 3, as shown in FIG. 14 (b), the injection vent 14 and the discharge vent 15 are opened. Then, the compressed gas 13 is poured through the opened injection vent 14 to promote the cooling of the resin 10.

  In the mold 8 of the above-described embodiment, as shown in FIG. 8B, one cavity piece 3 is configured to be slidable, and an injection vent 14 is provided on the slidable cavity piece 3 side. In addition, a discharge vent 15 is provided. However, as shown in FIG. 8B, when the injection vent 14 and the discharge vent 15 are provided on only one side, sink marks are generated on only one side of the resin 10, and thus warpage occurs in the molded product. Will end up. For this reason, as shown in FIG. 15, both the cavity pieces 3 are configured to be slidable, and the injection vent 14 and the discharge vent 15 are provided on both slidable cavity pieces 3 side. preferable. Thereby, since sink marks are generated in both of the resins 10, it is possible to suppress warping of the molded product. In addition, as shown in FIG. 11, when the area of the opening part of the injection | pouring ventilation hole 14 and the discharge | emission ventilation hole 15 is expanded and cooling efficiency is improved, it will become easy to generate | occur | produce a curvature in a molded article. For this reason, as shown in FIG. 11, when the areas of the openings of the injection vent 14 and the discharge vent 15 are expanded to improve the cooling efficiency, as shown in FIG. It is preferable to provide the injection vent 14 and the discharge vent 15.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment alone, and various modifications are made without departing from the gist of the present invention. Implementation is possible.

  For example, in the above-described embodiment, the injection molding has been described as an example. However, it is possible to mold a molded product by various molding methods such as extrusion molding and vacuum molding.

  Moreover, the control method at the time of shape | molding a molded article using the metal mold | die 8 of the said embodiment is not specifically limited, It is possible to carry out with arbitrary control methods.

2000 Image forming apparatus 2010 Optical scanning apparatus 2105c Deflector side scanning lens 8 Mold 1, 2 Mold insert 3 Cavity piece 5 Optical surface molding surface 6 Non-optical surface molding surface 7 Cavity 10 Resin 11 Vent 12 Flow path 13 Compressed gas 14 Vent for injection 15 Vent for discharge 20 Inlet 21 Gate

JP 2000-84945 A JP 2000-141413 A JP 2000-141425 A JP-A-11-28745 JP 2007-30339 A JP 2011-25433 A

Claims (6)

A cavity for molding a molded product by filling a resin is composed of a plurality of molding surfaces. The plurality of molding surfaces includes an optical surface molding surface for molding an optical surface on the molded product, and the molded product. A molding die having a non-optical surface molding surface for molding a non-optical surface,
A cavity piece having at least a part of the non-optical surface molding surface, at least one injection vent for blowing gas to the resin, and at least one discharge for discharging the gas blown to the resin. A vent, and
When the non-optical surface molding surface of the cavity piece is slid so as to be separated from the resin, the gas blown to the resin from the injection vent is discharged through the discharge vent. A molding die characterized by the above. The opening of the injection vent and the opening of the discharge vent constitute a side in contact with the cavity piece,
2. The molding die according to claim 1, wherein an opening of the injection vent and an opening of the discharge vent are located on the same axis.   2. The center axis of the opening of the injection vent and the center axis of the opening of the discharge vent are parallel to the non-optical surface molding surface of the cavity piece. The molding die according to claim 2.   The molding metal according to any one of claims 1 to 3, wherein an area of the opening of the jetting vent and an area of the opening of the discharging vent are the same. Type. The area of the opening of the jet vent is larger than the cross-sectional area of the jet vent other than the opening,
The molding according to any one of claims 1 to 4, wherein an area of the opening of the discharge vent is larger than a cross-sectional area of the discharge vent other than the opening. Mold. A cavity for molding an optical element by filling a resin is defined by a plurality of molding surfaces, the plurality of molding surfaces including an optical surface molding surface for molding an optical surface on the optical element, and the optical element An optical element molded with a molding die having a non-optical surface molding surface for molding a non-optical surface on
The molding die is
A cavity piece having at least a part of the non-optical surface molding surface, at least one injection vent for blowing gas to the resin, and at least one discharge for discharging the gas blown to the resin. A vent, and
When the non-optical surface molding surface of the cavity piece is slid so as to be separated from the resin, the gas blown to the resin from the injection vent is discharged through the discharge vent. An optical element characterized by being molded by the molding die.

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