JP3862950B2 - Optical writing apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical writing apparatus for irradiating a scanning surface of a plurality of image carriers arranged side by side with a light beam and writing a latent image, and a copying machine including the optical writing apparatus and forming a multicolor image The present invention relates to image forming apparatuses such as printers, facsimiles, and plotters.
[0002]
[Prior art]
Conventionally, a latent image is written by irradiating light beams emitted from a plurality of light sources onto four image carriers (for example, photosensitive drums) arranged in parallel, and latent images formed on the respective image carriers. The image is developed with different color developers (for example, yellow, magenta, cyan, and black toners) to be visualized, and then each transfer material such as recording paper carried on a transfer conveyance belt is carried on each image. The images are sequentially conveyed to the transfer section of the body, and each color visible image formed on each image carrier is transferred onto the transfer material, and then the image transferred on the transfer material is fixed to form a multicolor image. There are known tandem color image forming apparatuses.
[0003]
In such a tandem color image forming apparatus, conventionally, a latent image writing to each image carrier is separately performed by an optical writing device provided individually for each image carrier. An optical writing device using an optical deflector comprising a polygon mirror and its driving motor is relatively expensive, and it is necessary to provide an optical writing device for each image carrier individually in terms of component cost and manufacturing cost. There's a problem. Further, since a large installation space is required to install a plurality of optical writing devices having optical deflectors corresponding to the number of image carriers, there is a problem that the entire image forming apparatus is increased in size.
[0004]
Therefore, in order to reduce the cost and size of a tandem color image forming apparatus, as a means for performing optical writing on a plurality of image carriers, a light deflector is shared by a plurality of light sources, and one light deflector is used. There is known an optical writing apparatus for performing optical writing by simultaneously deflecting and scanning light beams from a plurality of light sources and irradiating a plurality of image carriers. As an example of this optical writing device, as shown in FIG. 12, a plurality of light source units 101, 102, 103, 104 and light beams L1, L1 from the plurality of light source units 101, 102, 103, 104 are provided. An optical deflector 105 that distributes and deflects L2, L3, and L4 in two symmetrical directions, and a plurality of optical deflectors 105 that are symmetrically arranged in the two directions around the optical deflector 105 and that are deflected and scanned by the optical deflector 105. There is a configuration including optical systems 106, 107, 108, 109, 110, and 111 for guiding the light beams L1, L2, L3, and L4 onto the corresponding scanned surfaces, respectively.
[0005]
In this optical writing apparatus, each of the four light source units 101, 102, 103, and 104 includes a semiconductor laser light source and a collimator lens. The light beams from the four light source units 101, 102, 103, and 104 are provided. L1, L2, L3, and L4 are deflected and scanned by, for example, distributing two light beams in two symmetrical directions by an optical deflector 105 including a polygon mirror and a driving motor thereof. The four light beams L1, L2, L3, and L4 that are deflected and scanned are image forming lenses 106 and 107 and an optical path folding mirror 108 that are arranged symmetrically in the two directions with respect to the optical deflector 105. , 109, 110, 111, etc., images are formed on the scanned surfaces of four image carriers (not shown), and the latent images are written by scanning the scanned surfaces at a constant speed in the main scanning direction.
[0006]
[Problems to be solved by the invention]
In the optical writing apparatus configured as shown in FIG. 12, the light beams L 1, L 2, L 3, and L 4 from the four light source units 101, 102, 103, and 104 are divided into two symmetrical directions by one optical deflector 105. Since the configuration is such that light beams are distributed and deflected and scanned, and latent images are written on the four image carriers, only one optical writing device is required, and the cost and size of the tandem color image forming apparatus can be reduced. .
[0007]
However, the optical systems 106, 107, 108, 109, 110, and 111 are arranged symmetrically with the optical deflector 105 as shown in FIG. 12 as the center, and the four optical beams L 1, L 2, and the like are arranged by one optical deflector 105. In the case of a configuration in which L3 and L4 are deflected and scanned by two light beams in two symmetrical directions, flare light from optical systems facing each other becomes a problem. For example, when a light beam is reflected / scattered on the incident surface side of the imaging lenses 106 and 107 facing each other with the optical deflector 105 interposed therebetween, the reflected / scattered light (flare light) is reversed. There is a problem that the optical carrier on the opposite side advances and the flare light that has entered enters the image carrier through the optical system. When flare light is applied to the image carrier, streak-like dirt or ghost images are generated on the image, or background dirt or color blur due to flare light fogging occurs, degrading image quality. Cause.
[0008]
The present invention has been made in view of the above circumstances, and a plurality of light beams are deflected and scanned in one symmetric two directions with one optical deflector, and scanned surfaces of a plurality of image carriers via an optical system. In the optical writing device configured to irradiate upward, even if flare light is generated by the optical systems facing each other across the optical deflector, the flare light is prevented from entering the opposite optical system. It is an object of the present invention to provide a means capable of preventing light from being irradiated onto a scanned surface of an image carrier.
[0009]
It is another object of the present invention to provide an image forming apparatus capable of preventing deterioration of image quality due to flare light generated in an optical writing apparatus and forming a high-quality multicolor image. .
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a plurality of light sources, an optical deflector that distributes and deflects light beams from the plurality of light sources in two symmetric directions, and the two directions around the optical deflector. Are arranged symmetrically to each other, and an optical system for guiding and imaging a plurality of light beams deflected and scanned by the optical deflector on corresponding scanning surfaces, respectively, and a plurality of the light sources, the optical deflector, and the optical system In an optical writing device in which the optical deflector is housed in a single housing, and arranged in the two directions so as to oppose each other around the optical deflector in the housing and outside the deflection scanning region of the light beam by the optical deflector. A light-shielding member that shields reflected / scattered light (flare light) from the optical system is provided.
[0011]
Here, as an example shown in FIG. 1, in the present invention, a plurality of light source units 52, 53, 54, and 55 and light beams L1, L2, L3, and L4 from the plurality of light source units are symmetric in two directions. An optical deflector 62 that distributes and deflects, and a plurality of light beams L 1, L 2, L 3, and L 4 that are arranged symmetrically in the two directions around the optical deflector 62 and deflected and scanned by the optical deflector 62, respectively. In an optical writing device provided with an optical system (imaging lenses 63, 64 and optical path folding mirrors 65, 66, 67, 68, etc.) that guides and forms an image on a corresponding scanning surface (not shown), an optical deflector 62. Of the light beam L1, L2, L3, and L4 by the optical deflector 62, and are provided in the two directions by the light shielding members 89 and 90 so as to oppose each other. Anti from the system And scattered light is obtained by a structure for blocking (flare light).
[0012]
Furthermore, in the optical writing device according to the present invention, the above-mentioned Departure In addition to the light configuration, the light shielding member is formed integrally with or attached to the base of the housing on which the optical system is disposed, and the light shielding member is opposed to the reflecting surface of the light deflector. More preferably, the base has a gap or notch serving as a passage through which airflow generated by rotation of the optical deflector escapes. 1 ).
[0013]
In the optical writing device according to the present invention, the above-mentioned Departure In addition to the light configuration, the optical system has a cover that is disposed at a position facing the base of the housing and covers at least the optical deflector, and the light shielding member is formed integrally with the cover, or A gap or a notch serving as a passage through which the air flow generated by the rotation of the light deflector escapes from the position attached to the cover and facing the reflecting surface of the light deflector of the light shielding member. It is desirable to have a configuration (claims) 2 ).
[0014]
An optical writing apparatus according to the present invention is the above-described claim 1. Or 2 In addition to the structure of the described invention, A plurality of the optical systems are arranged in parallel symmetrically across the optical deflector, and the light shielding member is in a direction perpendicular to the direction in which the plurality of optical systems are arranged in parallel, and the rotation center of the optical deflector Provided on the downstream side in the rotation direction of the optical deflector from a position on a vertical line passing through It is desirable to have a configuration (claims) 3 ).
[0015]
An optical writing apparatus according to the present invention is the above-described claim 1. Or 2 In the described optical writing device, A plurality of the optical systems are arranged in parallel symmetrically across the optical deflector, and the light shielding member is orthogonal to a rotation center axis of the optical deflector and a direction in which the plurality of optical systems are arranged in parallel. Provided on the downstream side in the rotation direction of the optical deflector from the position on the line It is desirable to have a configuration (claims) 4 ).
[0016]
An optical writing apparatus according to the present invention is the above-mentioned claim. 3 or 4 In addition to the configuration of the invention described above, it is desirable that the light shielding member has a wall surface that guides the airflow generated by the rotation of the optical deflector so as to escape to the downstream side in the rotation direction. 5 ).
[0017]
Further, according to the present invention, a plurality of image carriers arranged side by side, an optical writing means for writing a latent image by irradiating a light beam onto the scanning surface of the plurality of image carriers, and each image carrier Development means for developing the formed latent image with different color developers to make visible images, and transfer materials are sequentially conveyed to the positions of the image carriers, and each color formed on each image carrier is visible. An image forming apparatus comprising: a transfer unit that transfers an image superimposed on a transfer material; and a fixing unit that fixes an image transferred onto the transfer material. 5 It is set as the structure provided with the optical writing device as described in any one of Claims (Claims) 6 Thus, flare light generated in the optical writing device is prevented from being irradiated onto the scanned surface of the image carrier, and deterioration of image quality is prevented.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a schematic configuration diagram of the image forming apparatus, FIGS. 3 and 4 are diagrams illustrating an example of the configuration of the optical writing apparatus provided in the image forming apparatus shown in FIG. 2, and FIG. FIG. 4 is a cross-sectional view taken along the line AA ′ of FIG. 3. FIG. 1 shows the arrangement of the light source unit, the optical deflector, and the optical system extracted from the configuration shown in FIG. 3, and FIG. 5 shows the optical deflector and the optical system extracted from the configuration shown in FIG. The arrangement configuration is shown. FIG. 6 is a cross-sectional view of the main part around the light shielding member, and FIG. 7 is an explanatory diagram of the arrangement position of the light shielding member and its operation.
[0019]
The image forming apparatus shown in FIG. 2 is a full-color image forming apparatus in which a plurality of drum-shaped photoconductive photoreceptors (hereinafter referred to as photoreceptor drums) 1, 2, 3, and 4 are arranged in parallel as a plurality of image carriers. The four photosensitive drums 1, 2, 3, and 4 correspond to, for example, yellow (Y), magenta (M), cyan (C), and black (Bk) in order from the right in the drawing. An image is formed (the order of colors is not limited to this, and can be arbitrarily set). Around each of the four photosensitive drums 1, 2, 3, and 4, optical writing common to the photosensitive drums 1, 2, 3, and 4 is provided as a member for forming an image by an electrophotographic process. Optical writing device 5 as means, charging unit (charging roller, charging brush, charging charger, etc.) 6, 7, 8, 9 and developing unit as developing means (each color developing device of Y, M, C, Bk) 10 11, 11, 12, 13, transfer conveying belt 22 a and transfer means 22 including transfer means (transfer rollers, transfer brushes, etc.) 14, 15, 16, 17 disposed on the back surface thereof, a cleaning unit (cleaning blade, cleaning) 18, 19, 20, 21, etc. are provided, and image formation of each color can be performed on the respective photosensitive drums 1, 2, 3, 4.
[0020]
As shown in FIGS. 1, 3, 4, and 5, the optical writing device 5 includes four light source units 52, 53, 54, and 55 and light beams from the light source units 52, 53, 54, and 55. An optical deflector 62 that deflects and scans L1, L2, L3, and L4 in two symmetrical directions, and is arranged symmetrically in the two directions around the optical deflector 62, and is deflected and scanned by the optical deflector 62. Optical systems (imaging lenses 63, 64, 69, and 70) for guiding a plurality of light beams L1, L2, L3, and L4 onto the scanned surfaces of the corresponding photosensitive drums 1, 2, 3, and 4, respectively. , 71, 72, and optical path folding mirrors 65, 66, 67, 68, 73, 74, 75, 76, 77, 78, 79, 80, etc., and these components are contained in one housing 50. It is stored. More specifically, the four light source units 52, 53, 54, and 55 are installed on the side wall of the housing 50, the optical deflector 62 is disposed at a substantially central portion of the base 51 of the housing 50, and the optical system is the base 51. They are arranged separately on the upper surface side and the lower surface side (see FIG. 4). Covers 87 and 88 are provided at the upper and lower portions of the housing 50, and an opening through which the light beam passes is provided in the lower cover 87, and dustproof glasses 83, 84, 85, 86 is attached.
[0021]
In this optical writing device 5, color-separated image data input from a document reading device (scanner) or an image data output device (personal computer, word processor, facsimile receiving unit, etc.) (not shown) is used as a light source driving signal. The light source (semiconductor laser (LD)) in each light source unit 52, 53, 54, 55 is driven according to it, and the light beams L1, L2, L3, L4 are emitted. The light beams L1, L2, L3, and L4 emitted from the light source units 52, 53, 54, and 55 are cylindrical tilt correction lenses 56, 57, 58, and 59, and reflection mirrors 60 and 61 (provided that the light beams are provided). (Only with respect to L1 and L4), the light deflector 62 is passed through and deflected and scanned in two symmetrical directions by the two-stage polygon mirrors 62a and 62b rotated at a constant speed by the polygon motor 62c. 4 and 5, the polygon mirrors 62a and 62b are divided into two upper and lower stages for the light beams L2 and L3 and for the light beams L1 and L4. A configuration may be adopted in which deflection scanning is performed with a polygon mirror.
[0022]
The light beams L1, L2, L3, and L4 deflected and scanned in two directions by the polygon mirrors 62a and 62b of the optical deflector 62 are, for example, a first image forming unit composed of, for example, an fθ lens having two upper and lower layers. After passing through the lenses 63 and 64, respectively, after being folded back by the first folding mirrors 65, 66, 67 and 68 and passing through the opening of the base 51, a second imaging lens composed of a long toroidal lens or the like, for example. 69, 70, 71, 72 and passes through the second folding mirrors 73, 75, 77, 79, the third folding mirrors 74, 76, 78, 80, and the dustproof glasses 83, 84, 85, 86 for each color. Irradiated onto the surface to be scanned of the photosensitive drums 1, 2, 3 and 4 to write an electrostatic latent image.
[0023]
In the optical writing device 5 described above, the four light source units 52, 53, 54, and 55 are composed of a semiconductor laser (LD) as a light source and a collimating lens for collimating the emitted light beam of the semiconductor laser. The black light source unit (for example, the light source unit of reference numeral 54), which is integrated in the holder and used frequently during monochrome image formation, has two or more light sources in order to enable high-speed writing. A multi-beam configuration including (LD) and a collimating lens may be used. In the case of the multi-beam configuration, if the optical unit is configured to be rotatable about the optical axis with respect to the side wall of the housing 50, the beam pitch in the sub-scanning direction can be adjusted. The density (for example, 600 dpi, 1200 dpi, etc.) can be switched.
[0024]
Further, a synchronization detection mirror (not shown) for taking out the light beam at the scanning start position in the main scanning direction is provided in the optical path of each of the light beams L1, L2, L3, and L4, and is reflected by the synchronization detection mirror. The light beam is received by the synchronization detectors 81 and 82 as shown by broken lines in FIG. 5 and a scanning start synchronization signal is output. Further, as shown in FIG. 5, the third folding mirrors 74, 76, 78 arranged on the optical paths of the light beams L1, L2, L3 are provided with stepping motors 92.93, 94 for skew adjustment. The shift of the scanning line positions of the L1, L2, and L3 light beams is corrected with reference to the scanning line position of the L4 light beam.
[0025]
Note that the scanning direction of the light beams L1, L2, L3, and L4 deflected and scanned by the optical deflector 62 is the main scanning direction, which is the axial direction of the photosensitive drums 1, 2, 3, and 4. The direction perpendicular to the main scanning direction is the sub-scanning direction, which is the rotation direction of the photosensitive drums 1, 2, 3, 4 (moving direction of the surface of the photosensitive drum), and further, transfer conveyance described later. This is the conveying direction of the belt 22a. That is, the width direction of the transfer conveyance belt 22a is the main scanning direction, and the conveyance direction is the sub-scanning direction.
[0026]
As shown in FIG. 2, a transfer conveyance belt 22a stretched between a driving roller and a plurality of driven rollers is disposed under the four photosensitive drums 1, 2, 3, and 4 provided side by side. It is conveyed by the driving roller in the direction indicated by the arrow in the drawing. In addition, a plurality of paper feeding units 23 and 24 that store transfer materials such as recording paper are installed at the lower part of the main body of the image forming apparatus, and the transfer materials stored in these paper feeding units 23 and 24 are supplied. The paper is fed to the transfer / conveyance belt 22a via the paper roller, the conveyance roller, and the registration roller 25, and is carried and conveyed by the transfer / conveyance belt 22a.
[0027]
The latent images formed on the photosensitive drums 1, 2, 3, and 4 by the optical writing device 5 are developed with toners of Y, M, C, and Bk colors of the developing units 10, 11, 12, and 13, respectively. The visualized toner images of each color of Y, M, C, and Bk are carried on the transfer conveyance belt 22 a by the transfer units 14, 15, 16, and 17 of the transfer conveyance device 22. The images are sequentially superimposed on the transferred material. The transfer material onto which the four color images have been transferred is conveyed to a fixing unit 26 that is a fixing unit. After the image is fixed by the fixing unit 26, the transfer material is discharged onto a paper discharge tray 28 by a paper discharge roller 27.
[0028]
The basic configuration and operation of the optical writing apparatus and the image forming apparatus according to the present invention have been described above. However, as shown in FIG. When the optical deflector 62 is configured to deflect and scan the four light beams L1, L2, L3, and L4 in two symmetrical directions by two light beams, flare light from optical systems facing each other becomes a problem. For example, when a light beam is reflected and scattered by the incident surfaces of the first imaging lenses 63 and 64 facing each other with the optical deflector 62 interposed therebetween, the reflected and scattered light (flare light) is reversed. There is a problem in that it proceeds in the direction and enters the opposite optical system, and the flare light that has entered enters the photosensitive drums 1, 2, 3, and 4 through the optical system. When flare light is applied to the photosensitive drums 1, 2, 3, and 4, streak-like stains and ghost images are generated on the image, or background stains and blurring due to flare light fogging occur. As a result, the image quality deteriorates.
[0029]
Therefore, in the present invention, as shown in FIGS. 1 and 3, a plate-shaped light shielding member 89 around the optical deflector 62 and outside the deflection scanning region of the light beams L 1, L 2, L 3 and L 4 by the optical deflector 62. , 90 is provided, and the light shielding members 89, 90 are configured to shield the reflected / scattered light (flare light) from the optical systems arranged in the above-described two directions and facing each other. As a result, the flare light from the opposing optical system is prevented from being applied to the photosensitive drums 1, 2, 3, and 4, so that the image quality is prevented from deteriorating.
[0030]
Here, the base 51 of the housing 50 of the optical writing device 5 and the surrounding side walls are formed by resin integral molding. At this time, the light shielding members 89 and 90 can be formed integrally with the base 51. . FIG. 6 is a cross-sectional view of the periphery of the light shielding member 89 (90). The polygon is located below (on the base 51 side) the position opposite to the reflecting surface of the polygon mirrors 62a and 62b of the light shielding member 89 (90). It is preferable to provide a gap or notch 91 as a passage through which airflow generated by the rotation of the mirrors 62a and 62b escapes.
[0031]
That is, since the polygon mirrors 62a and 62b of the optical deflector 62 are rotating at high speed and an airflow is generated around the polygon mirrors 62a and 62b, the light shielding members 89 and 90 are located in the vicinity of the polygon mirrors 62a and 62b. Is provided, there is a case where an airflow hits the light shielding members 89 and 90 to generate noise and vibration. However, as shown in FIG. 6, when a gap or a notch 91 is provided below (on the base 51 side) a position opposite to the reflecting surface of the polygon mirrors 62a and 62b of the light shielding member 89 (90), Since the gap or the portion of the notch 91 serves as an escape path for the airflow, the contact of the airflow with respect to the light shielding member 89 (90) becomes weak, and the generation of noise and vibration can be greatly reduced.
[0032]
The gap formed between the light shielding member 89 and the cover 88 is also a passage through which airflow generated by the rotation of the polygon mirrors 62a and 62b escapes.
[0033]
Incidentally, the light shielding members 89 and 90 are provided around the optical deflector 62 and outside the deflection scanning region of the light beams L1, L2, L3, and L4 by the optical deflector 62. FIG. As shown in b), when the air deflector 62 is arranged on the line “A” orthogonal to the rotation center axis 62d of the polygon mirror 62a (62b) of the optical deflector 62 and the arrangement direction of the optical system, the air current is blocked by the light shielding member 89 (90 ) From a direction substantially perpendicular to the wall surface 95, the turbulence of the air current increases, and noise and vibration are likely to occur. Further, at this arrangement position, when the rotational position of the polygon mirror 62a (62b) reaches the position shown in FIG. 7B, it is between the light shielding member 89 (90) and the reflecting surface of the polygon mirror 62a (62b). Since the gap becomes wider, a part of flare light leaks from this gap, and there is a problem that the light shielding effect is reduced.
[0034]
Therefore, as means for solving these problems, as shown in FIGS. 7C and 7D, the light shielding member 89 (90) is connected to the rotation center axis 62d of the polygon mirror 62a (62b) of the optical deflector 62. A configuration in which the polygon mirror 62a (62b) is shifted from the opposite position to the downstream side in the rotation direction, in other words, the rotation center axis 62d of the polygon mirror 62a (62b) of the optical deflector 62 and the arrangement direction of the optical system. The position is set so as to be shifted from the position on the orthogonal line “A” to the downstream side in the rotational direction of the polygon mirror 62a (62b). The wall surface 95 of the light shielding member 89 (90) is directed to guide the airflow generated by the rotation of the polygon mirror 62a (62b) so as to escape downstream in the rotation direction.
[0035]
In the case where the light shielding member 89 (90) is arranged at such a position, the airflow advances along the wall surface 95 of the light shielding member 89 (90) and flows so as to escape to the tip side of the light shielding member 89 (90). Even if the light shielding member 89 (90) is provided, the turbulence of the airflow is less likely to occur, and the contact of the airflow against the light shielding member 89 (90) becomes very weak. Also in this case, as shown in FIG. 6, by providing a gap or a notch 91 on the lower side (base 51 side) of the light shielding member 89 (90), an airflow escape path on the base 51 side is also provided. Therefore, the generation of noise and vibration can be further reduced.
[0036]
Further, in this arrangement position, the tip of the light shielding member 89 (90) can be pushed out so as to be applied to the polygon mirror 62a (62b) when viewed from the optical system side, so that the polygon mirror 62a (62b) Even when the rotational position is the position shown in FIG. 7 (d), a gap for flare light leakage does not occur, so that a good light shielding effect can be obtained.
[0037]
In the present embodiment, the case where the light shielding members 89 and 90 are formed integrally with the base 51 of the housing 50 has been described as an example. However, the light shielding members 89 and 90 are formed separately from the housing 50 and screwed. You may attach to the base | substrate 51 by a stop, adhesion | attachment, etc.
[0038]
Next, a second embodiment of the present invention will be described with reference to FIG. The same portions as those described in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof is omitted (the same applies to the following embodiments). FIG. 8 is a plan view showing the arrangement of the light source unit, the optical deflector and the optical system in the optical writing apparatus.
[0039]
The basic configuration of the optical writing device 5a of the present embodiment is the same as that of the optical writing device 5 of the first embodiment, except that a light shielding member 96 is provided instead of the light shielding member 90. It is. The light shielding member 96 is outside the deflection scanning region of the light beams L1, L2, L3, and L4 by the optical deflector 62, and is opposite to the side facing the light source units 52, 53, 54, and 55 in the polygon mirror 62a (62b). It is formed in an arc shape surrounding the side. Further, the light shielding member 96 is formed integrally with the base 51 of the housing 50. The light shielding member 89 is the same as the light shielding member 89 of the first embodiment.
[0040]
Since the light shielding member 96 is formed in an arc shape surrounding the polygon mirror 62a (62b), the light shielding effect against flare light can be sufficiently enhanced.
[0041]
Further, since the light shielding member 96 is formed in an arc shape surrounding the polygon mirror 62a (62b), the air flow generated by the rotation of the polygon mirror 62a (62b) rotates smoothly along the inner peripheral surface of the light shielding member 96, The airflow does not hit the light shielding member 96 strongly, and the generation of noise and vibration caused by the airflow hitting the light shielding member 96 is reduced.
[0042]
Next, a third embodiment of the present invention will be described with reference to FIGS. 9 is a cross-sectional view, FIG. 10 is a plan view showing a state where the cover is removed, and FIG. 11 is a cross-sectional view showing the periphery of the light shielding member 89a.
[0043]
The basic configuration of the optical writing device 5b according to the embodiment is the same as that of the optical writing device 5a according to the second embodiment. The difference is that in the second embodiment, the light shielding member 89 is provided in the housing 50. The light shielding member 89a having the same function as the light shielding member 89 is attached to the cover 88a while being integrally formed with the base 51. The cover 88a is formed of a metal having good thermal conductivity in order to keep the temperature in the housing 50 uniform, and the light shielding member 89a is attached to the cover 88a by screwing or bonding. The light shielding member 89a may be formed integrally with the cover 88a.
[0044]
Further, FIG. 11 shows a cross-sectional view of the periphery of the light shielding member 89a. The polygon mirrors 62a and 62b are rotated above the position facing the reflecting surface of the polygon mirrors 62a and 62b of the light shielding member 89a (on the cover 88a side). It is preferable to provide a gap or notch 91a serving as a passage through which the generated airflow escapes. By providing such a gap or notch 91a, the airflow against the light shielding member 89a is weakened, and the generation of noise and vibration can be greatly reduced. A gap between the light shielding member 89a and the base 51 of the housing 50 is also a passage through which airflow generated by the rotation of the polygon mirrors 62a and 62b escapes.
[0045]
【The invention's effect】
In the first aspect of the present invention, a plurality of light sources, an optical deflector that distributes and deflects light beams from the plurality of light sources in two symmetric directions, and the two directions around the optical deflector. A plurality of light beams which are symmetrically arranged and deflected and scanned by the light deflector to guide and form images on the corresponding scanned surfaces, respectively, and the plurality of light sources, the light deflector and the optical system are provided in one housing; In the optical writing device housed in the housing, the reflection / reflection from the optical system arranged in the two directions and in the vicinity of the optical deflector in the housing and outside the deflection scanning region of the light beam by the optical deflector. By providing a light blocking member that blocks scattered light (flare light), even if flare light is generated by the optical systems facing each other across the optical deflector, the flare light enters the optical system on the opposite side. Can prevent It is possible to prevent the rare light is irradiated on the surface to be scanned of the image bearing member.
[0046]
Claims 1 In the optical writing device according to the invention described above, Departure In addition to the light configuration, the light shielding member is formed integrally with or attached to the base of the housing on which the optical system is disposed, and from a position facing the reflecting surface of the light deflector of the light shielding member. Since the base has a gap or notch that serves as a passage through which the airflow generated by the rotation of the optical deflector escapes, the gap or notch serves as an airflow escape path. As a result, the airflow hits against the air and the generation of noise and vibration can be reduced.
[0047]
Claims 2 In the optical writing device according to the invention described above, Departure In addition to the light configuration, the optical system has a cover that is disposed at a position facing the base of the housing and covers at least the optical deflector, and the light shielding member is formed integrally with the cover, or A configuration in which a gap or a notch serving as a passage through which an air flow generated by the rotation of the light deflector escapes is provided on the cover side from a position attached to the cover and facing the reflecting surface of the light deflector of the light shielding member. Thus, the gap or the notch serves as an airflow escape path, so that the contact of the airflow with respect to the light shielding member is weakened, and the generation of noise and vibration can be reduced.
[0048]
Claims 3 In the optical writing device according to the described invention, the above-mentioned claim 1 Or 2 In addition to the structure of the described invention, A plurality of optical systems are arranged in parallel symmetrically across the optical deflector, and the light shielding member is perpendicular to the direction in which the plurality of optical systems are arranged in parallel and passes through the rotation center of the optical deflector. Provided on the downstream side of the rotation direction of the optical deflector from the position on the line By adopting the configuration, the air flow becomes a flow that flows out to the tip along the wall surface of the light shielding member. And the occurrence of vibrations can be further reduced. In addition, in this arrangement position, since the tip of the light shielding member can be pushed out so as to cover the reflection surface of the optical deflector as viewed from the optical system side, a gap through which flare light leaks is generated. It becomes difficult to obtain a good light shielding effect.
[0049]
Claims 4 In the optical writing device according to the described invention, the above-mentioned claim 1 Or 2 In addition to the structure of the described invention, A plurality of optical systems are arranged in parallel symmetrically across the optical deflector, and the light shielding member is positioned from a position on a line orthogonal to the rotation center axis of the optical deflector and the direction in which the plurality of optical systems are arranged in parallel. Provided on the downstream side in the rotation direction of the optical deflector With this configuration, the tip of the light shielding member can be pushed out so as to cover the reflecting surface of the optical deflector when viewed from the optical system side. A light shielding effect is obtained.
[0050]
Claims 5 In the optical writing device according to the described invention, the above-mentioned claim is provided. 3 or 4 In addition to the configuration of the invention described above, the light shielding member is generated by the rotation of the optical changer by having a wall surface that guides the airflow generated by the rotation of the optical deflector so as to pass downstream in the rotation direction. Since the air flow is such that it flows to the tip along the wall surface of the light shielding member, the air flow is less likely to be disturbed, the air flow against the light shielding member can be extremely weakened, and noise and vibration can be further reduced. Can be reduced.
[0051]
And claims 6 In the described invention, a plurality of image carriers arranged side by side, an optical writing means for writing a latent image by irradiating a scanning surface of the plurality of image carriers with a light beam, and formed on each image carrier Development means for developing the latent image formed with different color developers to make visible images, and a visible image of each color formed on each image carrier by sequentially transferring the transfer material to the position of each image carrier In the image forming apparatus including a transfer unit that transfers the image transferred onto the transfer material and a fixing unit that fixes the image transferred onto the transfer material, the optical writing device configured as described above is used as the optical writing unit. By providing, it is prevented that the flare light generated in the optical writing device is irradiated onto the surface to be scanned of the image carrier, so that the deterioration of the image quality is prevented. Therefore, it is possible to realize an image forming apparatus that can prevent deterioration in image quality due to flare light generated in the optical writing apparatus and can form a high-quality multicolor image.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an arrangement configuration of a light source unit, an optical deflector, an optical system, and a light shielding member in an optical writing device according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of an image forming apparatus.
3 is a plan view showing a configuration on the upper surface side of a base in a housing of the optical writing device provided in the image forming apparatus shown in FIG. 2;
4 is a cross-sectional view taken along line AA ′ of the optical writing device shown in FIG. 3. FIG.
5 is a diagram showing an arrangement configuration of an optical deflector and an optical system extracted from the configuration of the optical writing device shown in FIG. 4; FIG.
FIG. 6 is a cross-sectional view of a main part around a light shielding member.
FIG. 7 is an explanatory diagram of an arrangement position of a light shielding member with respect to an optical deflector and its operation.
FIG. 8 is a schematic plan view showing an arrangement configuration of a light source unit, an optical deflector, an optical system, and a light shielding member in an optical writing device according to a second embodiment of the present invention.
FIG. 9 is a cross-sectional view showing an optical writing device according to a third embodiment of the present invention.
FIG. 10 is a plan view showing a state where a cover is removed.
FIG. 11 is a cross-sectional view of a main part around a light shielding member.
FIG. 12 is a schematic plan view showing an arrangement configuration of a light source unit, an optical deflector, and an optical system in a conventional optical writing apparatus.
[Explanation of symbols]
1,2,3,4 image carrier
5, 5a, 5b Optical writing device, optical writing means
10, 11, 12, 13 Developing means
14, 15, 16, 17 Transfer means
26 Fixing device
52, 53, 54, 55
50 housing
51 base
62 Optical deflector
63-80 optical system
88a cover
89, 89a, 90, 96 Shading member
91, 91a Clearance or notch
95 Wall
L1, L2, L3, L4 Light beam

Claims (6)

A plurality of light sources, an optical deflector that distributes and deflects light beams from the plurality of light sources in two symmetric directions, and is disposed symmetrically in the two directions with the optical deflector as a center. An optical writing apparatus comprising an optical system for guiding and imaging a plurality of light beams to be deflected and scanned on corresponding scanning surfaces, and housing the plurality of light sources, the optical deflector, and the optical system in one housing In
Reflected / scattered light (flare light) from the optical system disposed in the two directions and facing each other around the optical deflector in the housing and outside the deflection scanning region of the light beam by the optical deflector. A light shielding member for shielding light ;
The light shielding member is formed integrally with or attached to the base of the housing on which the optical system is arranged, and on the base side from a position facing the reflecting surface of the light deflector of the light shielding member, A gap or notch serving as a passage through which airflow generated by rotation of the optical deflector escapes;
An optical writing device comprising: A plurality of light sources, an optical deflector that distributes and deflects light beams from the plurality of light sources in two symmetric directions, and is disposed symmetrically in the two directions with the optical deflector as a center. An optical writing apparatus comprising an optical system for guiding and imaging a plurality of light beams to be deflected and scanned on corresponding scanning surfaces, and housing the plurality of light sources, the optical deflector, and the optical system in one housing In
Reflected / scattered light (flare light) from the optical system disposed in the two directions and facing each other around the optical deflector in the housing and outside the deflection scanning region of the light beam by the optical deflector. A light shielding member for shielding light;
A cover disposed at a position facing the base of the housing on which the optical system is disposed and covering at least the optical deflector; and the light shielding member is formed integrally with or attached to the cover; and A gap or notch serving as a passage through which the airflow generated by the rotation of the light deflector escapes from the position facing the reflecting surface of the light deflector of the light shielding member to the cover side,
An optical writing device comprising: In the optical writing device according to claim 1 or 2 ,
A plurality of the optical systems are arranged in parallel symmetrically across the optical deflector,
The light shielding member is provided on the downstream side in the rotation direction of the optical deflector from a position on a vertical line passing through the rotation center of the optical deflector in a direction perpendicular to a direction in which the plurality of optical systems are arranged in parallel. An optical writing device. In the optical writing device according to claim 1 or 2 ,
A plurality of the optical systems are arranged in parallel symmetrically across the optical deflector,
The light blocking member includes a feature the rotation center axis of the optical deflector, from the position of the line perpendicular to the direction in which the parallel arrangement of a plurality of the optical system, the provision of the downstream side in the rotational direction of said optical deflector Optical writing device. 5. The optical writing device according to claim 3 , wherein the light shielding member has a wall surface that guides an air flow generated by the rotation of the optical deflector so as to pass downstream in the rotation direction. 6. A plurality of image carriers arranged side by side, an optical writing means for writing a latent image by irradiating a light beam onto the scanning surface of the plurality of image carriers, and a latent image formed on each image carrier Developing means that develops with different color developers to make visible images, and sequentially transfers the transfer material to the position of each image carrier and overlays each color visible image formed on each image carrier on the transfer material In an image forming apparatus comprising transfer means for transferring together and fixing means for fixing an image transferred on a transfer material,
An image forming apparatus comprising the optical writing device according to claim 1 as the optical writing unit.

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