Light-transmissive plastic component, optical writing device, and image forming apparatus

Abstract

To provide, in a product having a light-transmissive part, a light-transmissive plastic component that contains an increased ratio of recycled material and exhibits improved quality despite the use of recycled material.SOLUTION: A light-transmissive plastic component has a light-transmissive part 70 that is formed of virgin material and allows light to transmit therethrough; and a recycled plastic part 72 that is formed of recycled plastic material. The light-transmissive part and the recycled plastic part are molded integrally.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a transmissive plastic part, an optical writing device, and an image forming apparatus. [Background technology]

[0002] A technology is being considered that involves recovering used resin parts and using the recycled resin as material to mold new resin parts.

[0003] Patent Document 1 discloses a recycled resin material obtained by mixing a specific copolymer resin with crushed material of a molded product of polycarbonate resin used in a vehicle lamp. Patent Document 1 also discloses that the crushed material is crushed lenses of a vehicle lamp, and that the recycled resin material is used to mold components other than the lenses of the vehicle lamp.

[0004] In Patent Document 1, defectively molded lenses for vehicle lamps are recycled and pelletized, and effectively used as molding material for components other than the lenses of vehicle lamps. The purpose of this invention is to improve the properties of the recycled resin so that the recycled products have excellent crack resistance to organic chemicals even under stress. Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional technologies, the ratio of recycled materials used is insufficient, and there is a demand to increase the ratio. In addition, even when recycled materials are used, there is a demand to improve the quality.

[0006] Therefore, an object of the present invention is to provide a transparent plastic part that increases the ratio of recycled materials used in a product having a transparent portion and has improved quality even when recycled materials are used. [Means for solving the problem]

[0007] In order to solve the above problems, the transparent plastic part of the present invention is made of virgin material and has a transparent portion that is capable of transmitting light, and a recycled plastic portion that is made of recycled plastic material, and is characterized in that the transparent portion and the recycled plastic portion are molded as a single unit. Effect of the Invention

[0008] According to the present invention, it is possible to provide a transparent plastic part having an improved quality even when using recycled materials by increasing the ratio of recycled materials used in a product having a transparent portion. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus. [Diagram 2] FIG. 1 is a schematic diagram illustrating an example of an optical writing device. [Diagram 3] FIG. 2 is a schematic plan view illustrating an example of an optical writing device. [Figure 4] FIG. 2 is a schematic diagram for explaining an example of a lens. [Diagram 5] FIG. 2 is a schematic diagram for explaining an example of a lens. [Figure 6] FIG. 2 is a schematic diagram for explaining an example of a lens. [Figure 7] FIG. 11 is a schematic diagram for explaining another example of a lens. [Figure 8] FIG. 2 is a schematic diagram for explaining an example of light passing through a lens. [Figure 9] FIG. 2 is a schematic diagram for explaining an example of light passing through a virgin material. [Figure 10] FIG. 2 is a schematic diagram for explaining an example of light passing through a virgin material. [Figure 11] FIG. 11 is a schematic diagram for explaining a lens of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The transparent plastic part, optical writing device, and image forming device according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, and may be modified within the scope of what a person skilled in the art can imagine, such as other embodiments, additions, modifications, and deletions, and any aspect is within the scope of the present invention as long as it provides the functions and effects of the present invention.

[0011] The transparent plastic part of the present invention is made of virgin material and has a transparent portion through which light can pass, and a recycled plastic portion made of recycled plastic material, and is characterized in that the transparent portion and the recycled plastic portion are molded as a single unit.

[0012] The use of the transmissive plastic part of the present invention can be appropriately selected, and it can be used in parts intended to transmit light and devices equipped with such parts. The transmissive plastic part of the present invention can be used as a part having a transmissive part, and the transmissive part is a part through which light transmits, such as a lens or a flat plate. When the transmissive part has a lens function, the transmissive plastic part may be called a lens part or the like.

[0013] The transmissive plastic part of the present invention can be used, for example, in an optical writing device used in an electrophotographic image forming apparatus. The optical writing device of the present invention has a light source and a transmissive plastic part, and is used in an electrophotographic image forming apparatus, the transmissive plastic part being the transmissive plastic part of the present invention, and the transmissive portion transmits light emitted from the light source. The optical writing device of the present invention may have a plurality of the transmissive plastic parts of the present invention.

[0014] The transparent plastic part of the present invention can be used in other devices besides image forming devices, such as projectors, cameras, smartphones, personal computers, etc. When the transparent plastic part of the present invention is used in these devices, the effect of increasing the loading ratio of recycled materials can also be obtained.

[0015] The image forming apparatus of the present invention includes an image carrier, an optical writing device that irradiates the image carrier with light, a charging means that charges the image carrier, and a developing means that develops the image carrier, and the optical writing device is the optical writing device of the present invention. The image forming apparatus of the present invention may include a plurality of the transparent plastic parts of the present invention.

[0016] According to the present invention, it is possible to provide a transmissive plastic part with a higher ratio of recycled materials in a product having a transmissive portion. The optical writing device and image forming device of the present invention can increase the ratio of recycled materials compared to conventional devices. Furthermore, in the present invention, when the transmissive portion has, for example, a lens function, it is possible to increase the ratio of recycled materials without impairing the lens function.

[0017] FIG. 1 is a schematic diagram for explaining an example of an image forming apparatus according to the present embodiment. The image forming apparatus 1 of this example is an example of a full-color image forming apparatus, and has a plurality of latent image carriers (which may also be called electrostatic latent image carriers, photoconductors, etc.). In this example, four drum-shaped photoconductors 10Y, 10C, 10M, and 10K are arranged in tandem as the latent image carriers. These photoconductors are configured as parts of the image forming devices 7Y, 7C, 7M, and 7K, which are image forming means. The image forming devices 7Y, 7C, 7M, and 7K correspond to the colors yellow, cyan, magenta, and black, respectively, and form images of these colors.

[0018] The image forming apparatus 1 of this example has an intermediate transfer belt 14 as a surface moving member. The intermediate transfer belt 14 rotates while being supported by three support rollers 15a, 15b, 15c, etc. The black arrow in the figure shows a schematic direction of movement of the intermediate transfer belt 14. Along the tension line on the lower side of the intermediate transfer belt 14, imaging devices 7Y, 7C, 7M, and 7K are arranged at intervals from the upstream side in the movement direction of the intermediate transfer belt 14.

[0019] When forming a full-color image, toner images (which may also be called toner images, visible images, etc.) of each color are formed on photoconductors 10Y, 10C, 10M, and 10K provided in image forming devices 7Y, 7C, 7M, and 7K.

[0020] The image forming apparatus 1 of this embodiment has a primary transfer roller 16 as a transfer means. The primary transfer roller 16 is disposed opposite each photoconductor with the intermediate transfer belt 14 therebetween. The toner images formed on the photoconductors 10Y, 10C, 10M, and 10K are transferred in sequence onto the intermediate transfer belt 14 by the function of the transfer roller 16, superimposed on top of each other, as the intermediate transfer belt 14 moves.

[0021] The location where the intermediate transfer belt 14 and the primary transfer roller 16 are in contact with each other is called a transfer position, and the transfer takes place at this transfer position. The toner image transferred onto the intermediate transfer belt 14 is also called a transferred toner image.

[0022] The transferred toner images are transferred all at once to a recording material (which may also be called a recording medium) at a nip portion between the support roller 15a and the secondary transfer roller 9. The toner images transferred to the recording material are fixed to the recording material by the fixing device 6. The fixing device 6 fixes the toner images on the recording material passing between the fixing roller 6a and the pressure roller 6b.

[0023] The recording material that has passed through the fixing device 6 passes through a transport roller and is discharged by a pair of discharge rollers onto a discharge tray 19. In this manner, a full-color image can be formed on the recording material.

[0024] Each of the imaging devices 7Y, 7C, 7M, and 7K will be described. The imaging devices 7Y, 7C, 7M, and 7K only differ in the color of toner they handle, and have the same mechanical configuration and image formation process. In the imaging devices 7Y, 7C, 7M, and 7K, the components other than the photoconductor are given the same reference numerals. Therefore, the configuration and image formation process of the imaging device 7Y will be described here as an example.

[0025] Around the photoconductor 10Y of the image forming device 7Y, there are arranged, in order of clockwise rotation in the figure, a charging roller 11 as a charging means, an irradiation position of the light beam L, a developing device 12 as a developing means, a primary transfer roller 16, a cleaning device 13, etc.

[0026] The light beam L is emitted from an optical writing device 4 serving as an optical scanning means. Inside the optical writing device 4, a semiconductor laser as a light source, a coupling lens, an fθ lens, a toroidal lens, a mirror, a deflector, etc. are provided. The optical writing device 4 emits a light beam L for each color toward each photoconductor, and irradiates the light beam L onto a writing position on the photoconductor 10Y to form an electrostatic latent image (also referred to as a latent image, etc.). Details will be described later.

[0027] The developing device 12 of the image forming device 7Y contains a yellow developer. The developing device 12 visualizes the latent image formed on the photoconductor 10Y. When the developer stored in the developing device 12 runs low, it is replenished from a yellow toner bottle as necessary. The other image forming devices also contain developers of their respective colors, and visualize the latent images with the color of the developer stored therein.

[0028] During image formation, the photoconductor 10Y rotates and is uniformly charged by the charging roller 11. Next, the photoconductor 10Y is irradiated with a light beam L containing yellow image information at the writing position, and an electrostatic latent image is formed. The formed electrostatic latent image is visualized by yellow toner while passing through the developing device 12.

[0029] The yellow toner image on the photoconductor 10Y is transferred to the intermediate transfer belt 14 by the primary transfer roller 16. Similarly, a cyan toner image by the image forming device 7C, a magenta toner image by the image forming device 7M, and a black toner image by the image forming device 7K are transferred in this order onto the intermediate transfer belt 14 in a superimposed manner. As a result, a full-color transferred toner image is formed on the intermediate transfer belt 14.

[0030] The recording material is sent out from the paper feed unit 5 so that it reaches the secondary transfer roller 9 at the same time as the transferred toner image reaches the secondary transfer roller 9. The recording material is conveyed by, for example, a registration roller. As described above, the transferred toner image is transferred collectively onto the recording material at the nip portion between the support roller 15A and the secondary transfer roller 9.

[0031] Meanwhile, after the transfer, the photoconductor is cleaned of residual toner by a cleaning device 13, and then is neutralized by a neutralization lamp in preparation for the next image formation. Similarly, residual toner and the like are removed from the intermediate transfer belt 14 by a cleaning device 17.

[0032] In the image forming apparatus 1 of this embodiment, the toner images on the photoconductors are once transferred onto the intermediate transfer belt 14 in an overlapping manner, and the overlapping toner images (transferred toner images) are transferred to the recording material all at once. The present invention is not limited to a method using the intermediate transfer belt 14, and may be a method using a recording paper conveying belt, which is a surface moving member, instead of the intermediate transfer belt 14. In this method, the recording material is placed on the recording paper conveying belt and conveyed, and the toner images from each photoconductor are sequentially transferred onto the recording material in an overlapping manner during the conveying process. This makes it possible to form a full-color image on the recording material. In addition, although the description has been given using an apparatus for forming a color image as an example, the present invention can also be applied to an apparatus for forming a monochrome image. The present invention can be applied to any of these types of image forming apparatuses.

[0033] Next, the optical writing device 4 that irradiates the light beam L will be described with reference to FIGS. Fig. 2 is a schematic cross-sectional view for explaining the optical writing device 4, and Fig. 3 is a schematic plan view for explaining the optical writing device 4. The optical writing device 4 in this example is a tandem scanning optical system, and employs a scanning lens system. The present invention is not limited to this, and can be applied to both the scanning lens system and the scanning mirror system.

[0034] The optical writing device 4 of this example includes a deflector 50, which is a main scanning line deflection means, various reflecting mirrors, various lenses, and other optical elements. The optical writing device 4 includes light sources 41K, 41M, 41C, and 41Y. The light sources 41K, 41M, 41C, and 41Y are an example of a light beam emitting means, and emit light beams L corresponding to the photoconductors 10K, 10M, 10C, and 10Y, respectively. Generally, a general-purpose semiconductor laser LD is used as the light source, and is soldered to a control board.

[0035] On the optical path of the light beam from the light source 41 to the mirror unit 49 of the deflector 50, a collimator lens 52 and a cylinder lens 53 are disposed for each corresponding light source 41. A cylinder lens is also called a cylindrical lens. On the optical path of the light beam from the mirror unit 49 of the deflector 50 to the photoconductor 10, a scanning lens 25 and a folding mirror 45 are disposed for each corresponding light source 41.

[0036] A second scanning lens may be disposed on the optical path of the light beam from the scanning lens 25 to the photoconductor 10. Also, a reflecting mirror 55 may be disposed on the optical path of the light beam from the light source 41 to the mirror portion 49 of the deflector 50.

[0037] The light beam emitted from the light source 41 is converted into a substantially parallel light by each collimator lens 52 and passes through the aperture. This forms a light beam L of a predetermined shape. The light beam L that passes through the aperture is incident on each cylindrical lens 53 and condensed. The light beam L that passes through the cylindrical lens 53 passes through the soundproof glass 51 and is incident on the side of the mirror portion 49 of the deflector 50, which is a main scanning line deflection means.

[0038] When the light beam L is incident on the side surface of the mirror portion 49 of the deflector 50, the light beam L is deflected and scanned in the main scanning line direction. The light beam L deflected and scanned by the mirror portion 49 of the deflector 50 passes through the soundproof glass 51 again, and then passes through the scanning lens 25, where the light beam is corrected so as to scan the photoconductor surface at a constant speed. The light beam is also corrected for the surface tilt of the mirror portion 49 of the deflector 50, is reflected by the folding mirror 45, and passes through the dustproof glass 28 attached to the cover member 32. The light beam then exits the optical writing device 4 and is irradiated onto the surface of the corresponding photoconductor 10.

[0039] In this example, a synchronous detection mechanism is provided, which determines, for example, the write start positions of black and magenta images. In the synchronous detection mechanism for black and magenta images, the light beam L that passes through the scanning lens 25 is reflected by the synchronous mirror 62KM, passes through the synchronous lens 63KM, and reaches the photo IC mounted on the control board 65KM, and the write start timing is detected. The same applies to the optical system MY corresponding to the cyan and yellow photoconductors 10M and 10Y.

[0040] These optical elements are disposed in a housing 31, and an upper opening of the housing 31 is closed by a cover member 32. A dustproof glass 28 through which the light beam L passes is disposed in the cover member 32, and the light beam L passes through the dustproof glass 28 to reach the photoconductor 10.

[0041] As described above, in an electrophotographic image forming apparatus, a light beam is irradiated from the optical writing device 4 onto the surface of an image carrier, and an electrostatic latent image is formed on the image carrier. The optical writing device 4 irradiates light emitted from a light source onto the image carrier (photoconductor) via a lens (collimator lens, cylindrical lens, fθ lens, etc.). A molded resin lens is used as the lens.

[0042] In conventional lens components having a lens function, the ratio of recycled materials used was insufficient. Therefore, in this embodiment, in a transmissive plastic component, virgin materials are used for the transmissive portion through which light can pass, and recycled plastic materials are used for the portions other than the transmissive portion. This makes it possible to increase the ratio of recycled materials used without impairing the lens function (lens performance) even when the transmissive plastic component is given a lens function. Furthermore, by increasing the ratio of recycled materials used, it is possible to reduce the amount of new resources required when producing new lens components.

[0043] The transparent portion is required to have, for example, a highly accurate lens surface, a uniform refractive index by suppressing distortion generated inside during molding, and a high transmittance, and virgin material for lenses is used for the transparent portion. On the other hand, parts other than the transparent portion, such as the positioning part, do not need to be made of virgin material because they do not require a function to transmit light. For this reason, recycled plastic material may be used for parts other than the transparent portion, such as the positioning part. In the present invention, the ratio of recycled plastic material is increased compared to when the transparent plastic parts are produced from virgin material. In other words, virgin material is used only for the necessary parts, so that it is possible to reduce the amount of new resources (virgin material) required when producing a new lens.

[0044] In a transparent plastic part, a portion made of recycled plastic material is referred to as a recycled plastic portion. The recycled plastic portion may also be referred to as a recycled material portion, a recycled material portion, etc. When the transparent portion has a lens function, the transparent portion may also be referred to as a lens portion, a lens portion, etc.

[0045] In the transparent plastic part of this embodiment, the transparent portion and the recycled plastic portion are molded as a single unit. The term "integrated" here refers to a state in which at least a part of the transparent part and at least a part of the recycled plastic part are in contact with each other and are attached to each other. However, the term "integrated" here also includes a case in which the connection between the transparent part and the recycled plastic part can be released by hand or with a tool. In addition, the case in which there is a boundary surface between the transparent part 70 and the recycled plastic part 72 is also included in the term "integrated."

[0046] For example, due to differences in linear expansion coefficients, stress may occur between the virgin material and the recycled plastic material due to environmental changes, causing deformation of the transmission part (lens). In the present invention, the transmission part and the recycled plastic part are molded as a single unit, thereby reducing the stress between the virgin material and the recycled plastic material and reducing deformation of the lens. Therefore, according to the present invention, quality can be improved even when recycled plastic material is used. It is an excellent advantage that quality can be ensured even when the ratio of recycled plastic material used is increased.

[0047] It is preferable that the material properties of the virgin material and the recycled plastic material are similar, and in this case, the quality of the transparent plastic part can be improved. To achieve this, for example, a lens of the same type as the newly manufactured transparent part (lens) is used, then crushed and recycled to create a recycled plastic material, so that the material properties of the virgin material and the recycled plastic material can be made similar.

[0048] An example of the virgin material is a virgin material of an optical resin. The virgin material may be called a virgin material or a virgin material. Recycled plastic materials may also be called recycled plastic materials, recycled materials, recycled materials, recycled resin materials, etc. Examples of recycled plastic materials include recycled plastic materials of optical resins, and materials obtained by recycling virgin materials used in the transmission parts can be used. For example, a transmission part formed of virgin materials can be recycled to produce recycled plastic materials. The recycling method can be appropriately selected, and examples include crushing, melting, etc.

[0049] In the transparent plastic part of this embodiment, the portion in which the recycled plastic material is used may be any portion other than the transparent portion, and may be appropriately selected. The recycled plastic portion is preferably a rib that supports the transparent portion, or a positioning portion that determines the position of the transparent portion. In this case, it is possible to avoid impairing the function (e.g., transmittance) required for the transparent portion. The positioning portion may be referred to as a positioning shape or the like.

[0050] It is preferable that the recycled plastic part is colored. When the recycled plastic part is colored, it is possible to suppress light from penetrating from the recycled plastic part side to the transparent part side. This makes it possible to suppress unnecessary light (e.g. ghost, flare, etc.), and the light transmitted through the transparent plastic part is more likely to become the desired light.

[0051] Whether or not the recycled plastic part is colored can be determined, for example, by measuring the light transmittance, and if the light transmittance of the recycled plastic part is 10% or more lower than that of the virgin material part, it can be said to be colored. Therefore, it is preferable that the recycled plastic part satisfies this range.

[0052] To obtain a colored recycled plastic part, for example, a method using a colored recycled plastic material, or a method of coloring the outside of the recycled plastic part after molding the recycled plastic part, is included. From the viewpoint of ease of production, etc., the method using a colored recycled plastic material is preferred.

[0053] The transmissive portion has an external surface, which is a light entrance surface, a light exit surface, and other surfaces, and it is preferable that the surface roughness of the interface between the transmissive portion and the recycled plastic portion is greater than the surface roughness of the other surfaces. Details are also explained in Fig. 10 below. The interface between the transmissive portion and the recycled plastic portion is also simply referred to as the interface. When the surface roughness of the boundary surface satisfies the above relationship, unwanted light (e.g. ghost, flare, etc.) generated when light incident on the transmissive part is reflected at the boundary surface can be dispersed, and the light transmitted through the transmissive plastic part becomes more likely to be the desired light.

[0054] Here is a supplementary explanation about the other surface. The other surface is one of the external surfaces (outer surfaces) of the transmitting part, and is not the light entrance surface of the transmitting part, and is not the light exit surface of the transmitting part. When there are multiple other surfaces, the surface with the greatest surface roughness can be selected as the relationship of the surface roughness of the above-mentioned boundary surface among the other surfaces.

[0055] To check whether the surface roughness of the boundary surface between the transmissive part and the recycled plastic part is greater than the surface roughness of other surfaces, it can be checked by taking into consideration, for example, the design contents, etc. Also, if the surface roughness of the boundary surface is large, the regular reflectance will be lower than that of the outer surface (lens surface) of the transmissive part, so by checking the regular reflectance, it can be checked whether the surface roughness relationship satisfies the above.

[0056] The above-mentioned relationship of the surface roughness of the boundary surface can be said to be a configuration in which the boundary surface is not flat. When the boundary surface is not flat, it is possible to disperse unnecessary light that is generated when light incident on the transmitting portion is reflected at the boundary surface. It can also be said that the above-mentioned relationship of the surface roughness of the boundary surface is specified in order to specify a configuration in which the boundary surface is not flat.

[0057] The specular reflectance of the boundary surface between the transmitting portion and the recycled plastic portion is preferably at least 10% lower than the specular reflectance of the light incident surface in the transmitting portion. In this case, too, it can be said that the boundary surface is not flat. By having the specular reflectance of the boundary surface at least 10% lower than the specular reflectance of the light incident surface in the transmitting portion, it is possible to disperse unnecessary light that is generated when light incident on the transmitting portion is reflected at the boundary surface. The specular reflectance can be measured by a known measurement method.

[0058] The shape of the transmitting part can be appropriately selected, and may be a lens shape, a flat plate shape, or other shapes. It can be appropriately selected according to the application of the transmitting plastic part. When the transmitting plastic part is used in an optical writing device or an image forming device, the shape of the transmitting part is preferably a lens shape. Examples of the lens shape include a convex lens shape and a concave lens shape, and when the transmitting plastic part is used in an optical writing device or an image forming device, the shape of the transmitting part is preferably a convex lens shape. The convex lens shape is, for example, a shape in which the thickness of the central part is thick, and the light entrance surface and the light exit surface are convex toward the outside of the transmitting part.

[0059] It is preferable that the transmitting part has a lens function in which the light entrance surface and the light exit surface are convex toward the outside of the transmitting part. In this case, virgin material is used in the part requiring lens performance, and the ratio of recycled materials can be increased without impairing the lens performance. In addition, the transmitting plastic parts can be used in optical writing devices and image forming devices, and the ratio of recycled materials can be increased. The phrase "having a lens function" may also be referred to as "having lens performance."

[0060] The transmissive plastic part of this embodiment can be used for the collimator lens 52, the cylinder lens 53 (cylindrical lens), the fθ lens, etc. in the optical writing device 4, for example.

[0061] 4 is a schematic cross-sectional view for explaining an example of a transmissive plastic part of this embodiment. The transmissive plastic part 68 of this example has a transmissive part 70 having lens performance and a recycled plastic part 72 not having lens performance. The transmissive part 70 is formed from a virgin material, and the recycled plastic part 72 is formed from a recycled plastic material (also called a recycled material). The transmissive part 70 is a member through which a light beam passes, and the range through which the light beam passes is also called an effective range, etc.

[0062] In this example, the recycled plastic portion 72 is used as a rib or a positioning portion. The rib has a function of supporting the transmitting portion 70, protecting the lens surface of the transmitting portion 70, and maintaining the strength of the transmitting portion 70. The positioning portion has a function of determining the position of the transmitting portion 70.

[0063] In the figure, a and b typically indicate the effective range requiring lens performance in the transmitting portion 70. The reason why a and b are illustrated as the effective range of the transmitting portion 70 is that the curvature differs between one side (side a) and the other side (side b) of the transmitting portion 70. However, this embodiment is not limited to this, and a and b may be the same size.

[0064] In the transparent plastic part 68 of this embodiment, the recycled plastic portion 72 is formed from recycled materials, and the ratio of recycled materials used is improved compared to the conventional example.

[0065] In Fig. 4, gate 71 is made of recycled plastic material and may be a part of recycled plastic portion 72. Gate 71 in this example is not a rib or a positioning portion. Gate 71 is a portion formed due to a mold or the like when molding recycled plastic material, as shown in Fig. 7 described later, for example.

[0066] Next, an example of a method for manufacturing the transparent plastic part of this embodiment will be described. Fig. 11 is a schematic cross-sectional view showing a comparative example of a transparent plastic part. This comparative example of a transparent plastic part is an example in which a lens portion 85 and a rib portion 86 are molded from virgin material. As shown in the figure, the lens portion 85 and the rib portion 86 are formed from the same material (virgin material). For this reason, the ratio of recycled material used is low.

[0067] This comparative example is an example of a case where air bubbles 89 occur in lens portion 85. When lens portion 85 and rib portion 86 are molded from virgin material, air bubbles 89 may occur, for example, at edge portion 88. When molten resin is forcefully injected from gate 87, air bubbles 89 may occur at edge portion 88. If air bubbles 89 reach the effective range of lens portion 85, the lens performance will deteriorate.

[0068] In order to prevent the generation of air bubbles, it is preferable to take measures such as the following: moving the edge portion away from the effective range of the lens portion, reducing the flow rate of the resin sent from the gate, modifying the mold to eliminate the edge portion, etc.

[0069] In this embodiment, when forming the transmissive portion 70 from virgin material, if there is no edge portion close to the effective range of the lens portion, there is no need to consider defects to the transmissive portion 70 caused by recycled plastic portions 72 such as ribs and positioning portions.

[0070] In this embodiment, the shape of the transmissive portion 70 can be designed by giving priority to a shape that allows the transmissive portion 70 to satisfy the lens performance. For example, after the shape of the transmissive portion 70 is designed, the shape of the recycled plastic portion 72, such as a rib or a positioning portion, is designed. In this way, since the shape of the transmissive portion 70 can be designed by giving priority to the shape, the transmissive portion 70 can easily satisfy the lens performance, and the quality is improved.

[0071] An example of how to manufacture a transparent plastic part according to this embodiment will be described with reference to Figures 5 to 7. Figures 5 to 7 are arranged in chronological order, and the illustrated example is an example of two-color molding.

[0072] 5 is a schematic cross-sectional view showing a state in which the transmitting portion 70 is formed from a virgin material. Reference numerals 73 to 75 denote a mold, and different reference numerals are used for each part of the mold. The virgin material is injected, for example, from an injection hole 74a.

[0073] Fig. 6 is a schematic cross-sectional view showing a state in which a mold 75, which is a part of a mold, is retracted after the transmitting portion 70 is formed as in Fig. 5. The arrow in the figure shows a schematic direction in which the mold 75 is retracted.

[0074] Fig. 7 is a schematic cross-sectional view showing a state in which a mold 76 has been moved after the mold 75 has been withdrawn as shown in Fig. 6. The mold 76 is a mold portion for forming the recycled plastic portion 72. The recycled plastic portion 72 is made of a recycled material. The recycled material is injected, for example, from an injection port 76a.

[0075] By forming the transmissive portion 70 and the recycled plastic portion 72 in the manner described above, the transmissive portion 70 made of virgin material and the recycled plastic portion 72 made of recycled material are integrally formed.

[0076] Thereafter, the molds 73, 74 corresponding to the entrance surface and exit surface of the transmission part 70 are removed, and the transmission plastic part is produced. When the recycled material is obtained by recovering the virgin material used in the transmission part 70, the linear expansion coefficients of the virgin material and the recycled material in the transmission plastic part are close to each other. Therefore, when a temperature change occurs in the transmission plastic part, the stress caused by the difference in thermal expansion within the transmission plastic part can be suppressed. The transmission plastic part formed by integrating the virgin material and the recycled material can also be recovered and used as the raw material for the transmission plastic part.

[0077] The recycled plastic portion 72 formed from recycled material does not include the effective range of the transmissive portion 70, and therefore can also be colored. Although the characteristics (e.g., transparency) of recycled material are inferior to those of virgin material, the recycled plastic portion 72 formed from recycled material does not need to perform as a lens. Therefore, by coloring the recycled plastic portion 72, the proportion of light that penetrates into the transmissive plastic part can be reduced, and unnecessary light (ghosts, flares, etc.) can be suppressed.

[0078] The transparent plastic part of this embodiment has an edge portion. The edge portion is a boundary portion between the surface of the transparent portion 70 and the surface of the recycled plastic portion 72, as shown in FIG. 4, for example, and is a portion that is not continuous with the smooth lens surface of the transparent portion 70. The edge portion may be provided in the recycled plastic portion 72 as shown in FIG. 7, for example, or in the transparent portion 70 as shown in FIG. 8, which will be described later. By having the edge portion, when pouring resin into a mold during injection molding, the generation of air bubbles, which cause internal defects, can be kept in the recycled plastic portion 72, and the generation of air bubbles in the transparent portion 70 can be suppressed.

[0079] 8 is a schematic cross-sectional view for explaining an example of a case where an interface occurs between the transmissive portion 70 and the recycled plastic portion 72. The virgin material forming the transmissive portion 70 and the recycled material forming the recycled plastic portion 72 have slightly different characteristics. Therefore, if the molding process of the transmissive portion 70 and the molding process of the recycled plastic portion 72 are not performed simultaneously, an interface 81 may occur between the transmissive portion 70 and the recycled plastic portion 72.

[0080] When an interface 81 is formed between the transmissive portion 70 and the recycled plastic portion 72, as shown by d in the figure, the light beam may be reflected at the interface 81. In addition, some of the unwanted light (ghost, flare, etc.) that has entered the transmissive plastic part may be reflected at the interface 81 and emitted from the transmissive plastic part as unwanted light. When this occurs, the electrostatic latent image formed on the photoconductor may not be formed with high precision, resulting in a deterioration in image quality.

[0081] 9 is an enlarged schematic diagram of a main part for further explaining FIG. 8, and is a schematic cross-sectional diagram for typically explaining light at the boundary surface 81. When the boundary surface 81 occurs between the transmissive portion 70 and the recycled plastic portion 72, the light beam may be reflected at the boundary surface 81. Also, a part of the unnecessary light that has entered the transmissive plastic part may be reflected at the boundary surface 81 and emitted from the transmissive plastic part as unnecessary light. As shown in d of the figure, the light beam is reflected at the boundary surface 81.

[0082] One way to reduce the influence of light reflected from boundary surface 81 is, for example, to increase the surface roughness of boundary surface 81. By increasing the surface roughness of boundary surface 81, the planar shape of boundary surface 81 is disrupted, and light reflected from boundary surface 81 is diffused. This makes it possible to reduce the influence of light reflected from boundary surface 81.

[0083] Fig. 10 is an enlarged schematic view of a main part for explaining an example in which the surface roughness of boundary surface 81 is made larger than in the examples shown in Fig. 8 and Fig. 9. Fig. 10 is also a schematic cross-sectional view for explaining light at boundary surface 81.

[0084] Due to the large surface roughness of boundary surface 81, the light beam is diffused, for example, as shown at e and f in the figure. If the surface roughness of boundary surface 81 were not large, the light would be reflected as shown at d, but due to the large surface roughness of boundary surface 81, the light is diffused as shown at e and f in the figure. As a result, the influence of the light reflected by boundary surface 81 can be suppressed.

[0085] In order to increase the surface roughness of the boundary surface 81, for example, a method of applying embossing to a mold when molding the transmissive portion 70 from a virgin material can be mentioned. In addition to the embossing, a certain pattern may be formed. When forming a pattern, it is preferable to set the pattern interval to be smaller than the diameter of the light beam incident on the transmissive portion 70.

[0086] 10 is an example in which the surface roughness of boundary surface 81 is large as described above, and this example can also be said to be an example in which boundary surface 81 is not flat. In addition, although the above-mentioned other surfaces are not clearly shown in the figure shown here, transmissive portion 70 has, as its outer surfaces, a light entrance surface, a light exit surface, and other surfaces. The surface roughness of boundary surface 81 is larger than the surface roughness of the other surfaces.

[0087] For example, aspects of the present invention are as follows. <1> a light transmitting portion made of a virgin material and capable of transmitting light; A recycled plastic part made of recycled plastic material, The transmission portion and the recycled plastic portion are molded as a single unit. A transparent plastic part characterized by: <2> The recycled plastic portion is a rib that supports the transmission portion or a positioning portion that determines the arrangement position of the transmission portion. Characterized by <1> The transparent plastic part according to claim 1. <3> The recycled plastic portion is colored. Characterized by <1> or <2> The transparent plastic part according to claim 1. <4> The transmission portion has, as an outer surface, a light incident surface, a light exit surface, and another surface, The surface roughness of the boundary surface between the transmission portion and the recycled plastic portion is greater than the surface roughness of the other surface. Characterized by <1> from <3> 2. The transparent plastic part according to claim 1 . <5> The regular reflectance of the boundary surface between the transmitting portion and the recycled plastic portion is 10% or more lower than the regular reflectance of the light incident surface of the transmitting portion. Characterized by <1> from <4> 2. The transparent plastic part according to claim 1 . <6> The transmission portion has a lens function in which the light entrance surface and the light exit surface are convex toward the outside of the transmission portion. Characterized by <1> from <5> 2. The transparent plastic part according to claim 1 . <7> An optical writing device for use in an electrophotographic image forming apparatus, the optical writing device having a light source and a transmissive plastic part, The transparent plastic part is <1> from <6> The transparent plastic part according to any one of claims 1 to 5, The transmission portion transmits light emitted from the light source. 1. An optical writing device comprising: <8> an image carrier; an optical writing device that irradiates light onto the image carrier; a charging unit that charges the image carrier; and a developing unit that develops the image carrier; The optical writing device is <7> The optical writing device according to 1. An image forming apparatus comprising: [Explanation of symbols]

[0088] 4 Optical writing device 6 Fixing device 7 Imaging device 10 Photoreceptor 11 Charging roller 12 Developing device 13 Cleaning equipment 14 Intermediate transfer belt 16 Primary transfer roller 52 Collimating Lens 53 Cylinder Lens 41 Light source 84 Edge 85 Bubbles 70 Transparent part Gate 71 72 Recycled Plastics Department 73~76 Mold 81 Boundary [Prior art documents] [Patent documents]

[0089] [Patent Document 1] JP 2007-254603 A

Claims

1. a light transmitting portion made of a virgin material and capable of transmitting light; A recycled plastic part made of recycled plastic material, The transparent portion and the recycled plastic portion are molded as a single unit. A transparent plastic part characterized by:

2. The recycled plastic portion is a rib that supports the transmission portion or a positioning portion that determines the arrangement position of the transmission portion.

2. The transparent plastic part according to claim 1.

3. The recycled plastic portion is colored.

2. The transparent plastic part according to claim 1.

4. The transmission portion has, as an outer surface, a light incident surface, a light exit surface, and another surface, The surface roughness of the boundary surface between the transmission portion and the recycled plastic portion is greater than the surface roughness of the other surface.

2. The transparent plastic part according to claim 1.

5. The regular reflectance of the boundary surface between the transmitting portion and the recycled plastic portion is 10% or more lower than the regular reflectance of the light incident surface of the transmitting portion.

2. The transparent plastic part according to claim 1.

6. The transmission portion has a lens function in which the light entrance surface and the light exit surface are convex toward the outside of the transmission portion.

2. The transparent plastic part according to claim 1.

7. An optical writing device for use in an electrophotographic image forming apparatus, the optical writing device having a light source and a transmissive plastic part, The transparent plastic part is a transparent plastic part according to any one of claims 1 to 6, The transmission portion transmits light emitted from the light source.

1. An optical writing device comprising:

8. an image carrier; an optical writing device that irradiates light onto the image carrier; a charging unit that charges the image carrier; and a developing unit that develops the image carrier; The optical writing device is the optical writing device according to claim 7.

1. An image forming apparatus comprising:

Images