JP2004109722A - Optical scanner and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an optical element from having temperature deviation due to heat from a deflection part. <P>SOLUTION: The deflection part 62 which is driven to rotate to deflect light beams L1, L2, L3 and L4 emitted by light sources and optical elements 24 and 25 which convert the light beams L1, L2, L3 and L4 deflected by the deflection part 62 from equal-angular-velocity scanning light to equal-speed scanning light are supported by a 1st housing 43. This 1st housing 43 is formed of a material having higher heat conductivity than materials of optical elements 24 and 25. Consequently, the heat generated at the deflection part 62 is efficiently conducted to the optical elements 24 and 25. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical scanning device and an image forming apparatus provided with the optical scanning device.
[0002]
[Prior art]
An optical scanning device used in an image forming apparatus such as a printer or a copier emits a light beam based on image information, and the polygon mirror, which is a deflecting unit driven at high speed, rotates the light beam at a constant angular velocity in a main scanning direction. Scanning is performed by converting an equiangular scanning light into an equal speed scanning light by an fθ lens as an optical element to perform exposure scanning on a photoconductor (for example, see Patent Document 1).
[0003]
The polygon mirror and the fθ lens of such an optical scanning device are supported by a housing. As the housing, a housing made of resin to reduce the cost of the optical scanning device is widely used.
[0004]
Some optical scanning devices are mounted on a housing with the polygon mirror hermetically closed in order to prevent noise generated by rotating the polygon mirror at high speed.
[0005]
[Patent Document 1]
JP-A-9-197330
[0006]
[Problems to be solved by the invention]
However, in such an optical scanning device, the polygon mirror is heated by rotating the polygon mirror at a high speed. Generally, resin materials have a low thermal conductivity, so in an optical scanning device in which the housing is formed of resin as described above, heat generated by the polygon mirror is difficult to be transmitted to the surroundings and stagnant near the heat source. It's easy to do. For this reason, a situation occurs in which the temperature differs for each part of the housing.
[0007]
In an fθ lens that occupies a large space in the housing, a temperature difference occurs due to a difference in temperature for each part of the housing, and the rate of change due to thermal expansion is biased for each part.
[0008]
Further, when the polygon mirror is provided in a closed state, the temperature of the polygon mirror portion is intensively increased, which causes a large temperature deviation in the fθ lens.
[0009]
In an image forming apparatus using such an optical scanning device, when a temperature deviation occurs in an fθ lens or the like, the scanning speed on the image plane on the photoconductor changes depending on the portion of the fθ lens, and the magnification of the image changes in each portion. Resulting in. For this reason, a magnification deviation may occur in the main inspection direction, and a high-quality image may not be obtained.
[0010]
An object of the present invention is to prevent a temperature deviation from occurring in an optical element due to heat from a deflection unit.
[0011]
[Means for Solving the Problems]
The light scanning device according to the first aspect of the present invention includes a light source that emits a light beam based on image information, a deflecting unit that is driven to rotate and deflects the light beam emitted from the light source, and is deflected by the deflecting unit. An optical element for converting a light beam from constant angular velocity scanning light to constant velocity scanning light, and a first housing formed of a material having a higher thermal conductivity than the material of the optical element and supporting the deflection unit and the optical element And.
[0012]
Therefore, the heat generated in the deflecting unit is efficiently transmitted to the optical element, and the occurrence of a temperature deviation in the optical element is prevented. This prevents a magnification deviation from occurring in the main scanning direction.
[0013]
According to a second aspect of the present invention, in the optical scanning device according to the first aspect, a material of the first housing is a metal, and a material of the optical element is a resin.
[0014]
Therefore, it is possible to reduce the cost of the optical scanning device.
[0015]
According to a third aspect of the present invention, in the optical scanning device according to the first or second aspect, one of the second housing supporting the first housing and the first housing and the second housing is provided. And a first fitting piece provided in one of the other of the first housing and the second housing, wherein the first hole is provided in the first hole. A first fitting portion in which the fitting pieces are slidably fitted, a second hole provided in one of the first housing and the second housing, Having a second fitting piece provided on one of the other of the housing and the second housing, wherein the second hole and the second fitting piece are moved to the first positioning portion. With play in the direction of contact and separation of the first and the sliding direction of the first fitting piece into the first hole. And a second fitting portion that is positioned, and the first housing and the second housing are positioned by the first fitting portion and the second fitting portion. .
[0016]
Therefore, even when the first housing and the second housing have different linear expansion coefficients, when heat is generated in the deflecting unit, the thermal expansion of the first housing and the second housing is reduced by the second expansion coefficient. It is possible to prevent the first housing and the second housing from being distorted without being restricted by the fitting portion.
[0017]
According to a fourth aspect of the present invention, in the optical scanning device according to the third aspect, a material of the first housing has a higher thermal conductivity than a material of the second housing.
[0018]
Therefore, the heat generated in the deflecting portion is efficiently transmitted to the second housing.
[0019]
According to a fifth aspect of the present invention, in the optical scanning device according to the fourth aspect, a material of the second housing is a resin.
[0020]
Therefore, it is possible to reduce the cost of the optical scanning device.
[0021]
According to a sixth aspect of the present invention, in the optical scanning device according to the first, second, third, fourth, or fifth aspect, a cover for covering each part of the device is provided, and the cover has an opening for exposing the inside of the cover. Have.
[0022]
Therefore, heat is released from the opening, and a rise in the temperature of the entire optical scanning device is suppressed, thereby making it possible to prevent a temperature deviation of the optical element from occurring, and to suppress a rise in the temperature of the optical element. It becomes possible.
[0023]
According to a seventh aspect of the present invention, in the optical scanning device according to the sixth aspect, the first housing has a fin formed so as to protrude from the opening to the outside of the cover to perform heat radiation.
[0024]
Therefore, heat is released from the fins, and the temperature rise of the entire optical scanning device is suppressed, whereby it is possible to prevent the occurrence of temperature deviation of the optical element, and to suppress the temperature rise of the optical element. Becomes possible.
[0025]
According to an eighth aspect of the present invention, in the optical scanning device according to the first, second, third, fourth, fifth or sixth aspect, a plurality of the light sources and the plurality of optical elements are provided, and a plurality of the optical elements are provided. And converting the different light beams from constant angular velocity scanning light to constant velocity scanning light.
[0026]
Therefore, it is possible to prevent a temperature deviation and a magnification deviation from occurring in each of the plurality of optical elements, thereby preventing the relative positions of the plurality of light beams from being different.
[0027]
An image forming apparatus according to a ninth aspect of the present invention is an image forming apparatus, an image carrier, a charging unit for charging the image carrier, and a surface of the image carrier that is exposed and scanned to form an electrostatic latent image on the surface. An optical scanning device according to any one of 1 to 8, further comprising: a developing unit that develops the electrostatic latent image with toner to form a toner image; and a transfer unit that transfers the toner image to a recording medium.
[0028]
Therefore, the same operation as the invention according to any one of claims 1 to 8 is achieved. As a result, a change in magnification in an image formed on the recording medium can be prevented. In the case where a plurality of light sources are provided, overlapping of the light beams on the image carrier is prevented, so that a change in the tint of the image can be prevented.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. This embodiment is an example of application to a tandem-type full-color laser printer (hereinafter, simply referred to as a laser printer) including an optical scanning device.
[0030]
FIG. 1 is a vertical sectional front view schematically showing a laser printer according to the present embodiment. As shown in FIG. 1, four image forming units 3 (3Y, 3C, 3M, 3B) and light beams L (L1, L2, L3, L4) are provided at a substantially central portion inside the main body case 2 of the laser printer 1. ), And an intermediate transfer belt 5 are disposed. Each image forming unit 3 is a part for forming an image (toner image) of a different color. In the description of the present specification and the drawings relating to the image forming unit 3 and the components of the image forming unit 3, Y, The subscripts of C, M, and B indicate the colors of yellow, cyan, magenta, and black, respectively.
[0031]
The four image forming units 3Y, 3C, 3M, and 3B have different colors of images to be formed due to different colors of toner used, and have the same basic structure.
[0032]
Each image forming unit 3 includes a photoconductor 6 (6Y, 6C, 6M, 6B) as an image carrier that is driven to rotate in the direction of an arrow, a charging unit 7, a developing unit 8, and a cleaning unit arranged around the photoconductor 6. It is composed of a unit 9 and the like.
[0033]
The photoconductor 6 is formed in a cylindrical shape, and is rotationally driven by a driving source (not shown). A photosensitive layer is provided on the outer peripheral surface of the photoconductor 6, and the outer peripheral surface 6a, which is the surface of the photoconductor 6, is a surface to be scanned. By irradiating the light beam L emitted from the optical scanning device 4 to the outer peripheral surface 6a of the photoreceptor 6, an electrostatic latent image corresponding to image information is written on the outer peripheral surface 6a of the photoreceptor 6. An irradiation slit 10 for irradiating the light beam L emitted from the optical scanning device 4 to the outer peripheral surface 6a of each photoconductor 6 is provided between the charging unit 7 and the developing unit 8 in each image forming unit 3. Is provided.
[0034]
The charging unit 7 uniformly charges the outer peripheral surface 6a of the photoconductor 6, and a non-contact type with respect to the photoconductor 6 is employed.
[0035]
The developing unit 8 supplies the toner to the photoconductor 6, and the supplied toner adheres to the electrostatic latent image written on the outer peripheral surface 6 a of the photoconductor 6, thereby forming the electrostatic latent image on the photoconductor 6. Is a toner image, and a non-contact type is used for the photoconductor 6.
[0036]
The cleaning section 9 is for cleaning residual toner adhering to the outer peripheral surface 6a of the photoconductor 6, and employs a brush contact type in which a brush is brought into contact with the outer peripheral surface 6a of the photoconductor 6.
[0037]
The intermediate transfer belt 5 is a loop-shaped belt formed using a resin film or rubber as a base, and transfers the toner image formed on the photoconductor 6. The intermediate transfer belt 5 is supported by rollers 11, 12, and 13 and is driven to rotate in the direction of the arrow. On the inner peripheral surface side (inside of the loop) of the intermediate transfer belt 5, four intermediate transfer belts 5 are pressed against the photoconductor 6 in order to transfer the toner image on each photoconductor 6 onto the intermediate transfer belt 5. A transfer roller 14 is provided. On the outer peripheral surface 6a side of the intermediate transfer belt 5 (outside the loop), a cleaning unit 15 for cleaning residual toner, paper dust, and the like attached to the outer peripheral surface 6a of the intermediate transfer belt 5 is arranged.
[0038]
Below the four image forming units 3 and the optical scanning device 4 in the main body case 2, a paper feed cassette 16 in which recording media (sheets) A are stacked and held is arranged. The recording media A stacked and held in the paper feed cassette 16 are separated and fed in order from the top one.
[0039]
A transport path 17 through which the recording medium A separated and fed from the paper feed cassette 16 is transported is formed in the main body case 2. On the transport path 17, a registration roller 18, an intermediate transfer roller 19, a fixing unit 20, a paper discharge roller 21 and the like are arranged.
[0040]
The registration roller 18 is a roller that is intermittently driven to rotate at a predetermined timing. When the registration roller 18 is intermittently driven to rotate, the recording medium A that has been conveyed to the position of the registration roller 18 and stopped is sent to a transfer position between the intermediate transfer belt 5 and the intermediate transfer roller 19. At this transfer position, the toner image on the intermediate transfer belt 5 is transferred to the recording medium A. Here, a transfer section is configured by the intermediate transfer belt 5 and the intermediate transfer roller 19.
[0041]
The fixing section 20 is a section for fixing the toner image transferred onto the recording medium A to the recording medium A by applying heat and pressure. The recording medium A on which the toner image has been fixed in the process of passing through the fixing section 20 is discharged by a discharge roller 21 onto a discharge tray section 22 formed on the upper surface of the main body case 2.
[0042]
Next, the optical scanning device 4 will be described with reference to FIG. FIG. 2 is a vertical sectional front view schematically showing the optical scanning device 4.
[0043]
The optical scanning device 4 includes four light source units (not shown), an optical deflector 23 that deflects and scans the light beams L1, L2, L3, and L4 from the respective light source units in two symmetric directions. And a plurality of light beams L1, L2, L3, and L4, which are symmetrically arranged in the two directions and are deflected and scanned by the optical deflector 23, respectively, and correspond to the outer peripheral surfaces 6a of the corresponding photoconductors 6Y, 6C, 6M, and 6B. An optical system for guiding and forming an image (fθ lenses 24 and 25 as optical elements, toroidal lenses 26, 27, 28 and 29, mirrors 30, 31, 32, 33, 34, 35, 36, 37 and 38 for turning back the optical path) , 39, 40, 41, etc.), and these components are housed inside the housing 42.
[0044]
The housing 42 includes a first housing 43 that holds the optical deflector 23 and the fθ lenses 24 and 25, a housing that supports the first housing 43 on a lower surface thereof, and accommodates each part of the optical scanning device 4 (the toroidal lens 26). , 27, 28, 29, and a second housing 44 for accommodating and supporting the optical path turning mirrors 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, etc.). I have. The first housing 43 is formed of aluminum which is a metal, and the second housing 44 is formed of resin. The thermal conductivity of the first housing 43 is higher than the thermal conductivity of the second housing 44 and the fθ lenses 24 and 25.
[0045]
The second housing 44 covers each part of the optical scanning device 4 and functions as a cover. An opening through which the light beam L passes is provided in the upper part of the second housing 44, and dustproof glass 45, 46, 47, 48 is attached to the opening. The lower surface of the second housing 44 is provided with two openings 49 and 50 for exposing the second interior. From the openings 49 and 50 of the second housing 44, fins 51 and 52 formed in the first housing 43 and dissipating heat project outside.
[0046]
The first housing 43 is positioned with respect to the second housing 44 by the first fitting portion 53 and the second fitting portion 54.
[0047]
The first fitting portion 53 includes a cylindrical portion 55, which is a first fitting piece formed to protrude downward at the center of the first housing 43, and a lower surface of the second housing 44. And a first hole 56 formed at the center of the portion and into which the cylindrical portion 55 is slidably fitted.
[0048]
The second fitting portion 54 has two long holes 57, 58 formed at both ends of the lower surface of the second housing 44 with the first hole 56 interposed therebetween, and is inserted through the long holes 57, 58. The first housing 43 includes stepped screws 59 and 60 as second fitting pieces attached to the lower portions of both ends of the first housing 43 with the cylindrical portion 55 interposed therebetween. The axial directions of these stepped screws 59 and 60 are the same as the axial direction of the cylindrical portion 55, that is, the same as the sliding direction a of the cylindrical portion 55 into the first hole 56.
[0049]
The long holes 57 and 58 are formed with the direction of contact / separation b with respect to the first fitting portion 53 as the longitudinal direction. In the stepped screws 59 and 60, a step 61 formed between the screw portion and the head is inserted into the elongated holes 57 and 58. The axial length (height) of the step 61 is set longer than the thickness of the second housing 44, and the diameter of the step 61 is smaller than the longitudinal width of the long holes 57 and 58. Is set. As a result, the stepped screws 59 and 60 are moved in the longitudinal direction of the long holes 57 and 58 (the direction “b” that comes into contact with and separate from the first fitting portion 53) and the sliding direction “a” of the cylindrical portion 55 toward the first hole 56. It is possible to move. In other words, the stepped screws 59 and 60 play in the long holes 57 and 58 with play in the direction b of coming and going to the first fitting portion 53 and the sliding direction a of the cylindrical portion 55 toward the first hole 56. It is fitting. Here, the stepped screws 59 and 60 constitute a part of the first housing 43.
[0050]
The optical deflector 23 has a polygon mirror 62 as a deflecting unit, and the polygon mirror 62 is driven to rotate at a high speed and a constant speed by a polygon motor (not shown). The polygon mirror 62 includes two-stage polygon mirrors 62a and 62b. In the optical deflector 23, the light beam L is scanned at a constant angular velocity by the polygon mirror 62 driven at a constant speed. The polygon mirror 62 and the polygon motor are held by a holding portion 55 a formed in the cylindrical portion 55 of the first housing 43. The polygon mirror 62 and the polygon motor are housed in a closed space S which is substantially closed by an inner cover 63 and a sound insulating glass 64. A seal member 65 for improving the airtightness is provided between the inner cover 63 and the sound insulating glass 64. Then, the light beam L deflected by the polygon mirror 62 passes through the sound insulating glass 64. 1 and 2, the polygon mirrors 62a and 62b are divided into upper and lower stages for the light beams L1 and L4 and for the light beams L2 and L3. A configuration in which deflection scanning is performed by a thick polygon mirror may be employed.
[0051]
lenses 24 and 25 are imaging lenses formed of a resin material, and are held by the first housing 43 at positions sandwiching the polygon mirror 62. Lenses 24 and 25 have an upper and lower two-layer structure. Lenses 25 convert the light beam L deflected by the polygon mirror 62 from constant angular velocity scanning light to constant velocity scanning light.
[0052]
The optical scanning device 4 converts color-separated image information input from a document reading device (scanner) or an image information output device (personal computer, word processor, etc.) (not shown) into a signal for driving a light source. The light source (semiconductor laser (LD)) in each light source unit is driven based on the light beams to emit light beams L1, L2, L3, and L4. The light beams L1, L2, L3, and L4 emitted from each light source unit are deflected and scanned in two symmetrical directions by two-stage polygon mirrors 62a and 62b rotated at a constant speed by a polygon motor.
[0053]
The light beams L1, L2, L3, and L4, which are deflected and scanned in two directions by two beams by the polygon mirrors 62a and 62b of the light deflector 23, pass through the sound insulating glass 64, and are scanned by the fθ lenses 24 and 25 from the uniform angular velocity scanning light. The light is converted into constant-speed scanning light, is folded by the first folding mirrors 30, 31, 32, and 33, passes through the toroidal lenses 26, 27, 28, and 29, and passes through the second folding mirrors 34, 36, 38, 40, Irradiation is performed on the outer peripheral surfaces 6a of the photoconductors 6Y, 6C, 6M, 6B for the respective colors via the three-fold mirrors 35, 37, 39, 41 and dustproof glass 45, 46, 47, 48 to write an electrostatic latent image.
[0054]
Here, the scanning direction of the light beams L1, L2, L3, and L4 deflected and scanned by the optical deflector 23 is the main scanning direction, which is the axial direction of each of the photoconductors 6Y, 6C, 6M, and 6B. The direction orthogonal to the main scanning direction is the sub-scanning direction, which is the rotation direction of the photoconductors 6Y, 6C, 6M, 6B (the moving direction of the outer peripheral surface 6a of the photoconductor 6), and furthermore, the intermediate transfer. This is the conveying direction of the belt 5. That is, the width direction of the intermediate transfer belt 5 is the main scanning direction, and the transport direction is the sub-scanning direction.
[0055]
In such a configuration, when a color image is printed, toner images of different colors are formed on the outer peripheral surface 6a of the photoconductor 6 of each image forming unit 3, and the intermediate transfer belt 5 is formed on the outer peripheral surface 6a of each photoconductor 6. Is pressed, the toner image on the photoreceptor 6 is overlaid and transferred onto the intermediate transfer belt 5, and a color toner image is formed on the intermediate transfer belt 5. The color toner image formed on the intermediate transfer belt 5 is recorded while the recording medium A separated and fed from the paper feed cassette 16 passes through a position sandwiched between the intermediate transfer belt 5 and the intermediate transfer roller 19. The image is transferred to the medium A. The color toner image transferred onto the recording medium A is fixed while the recording medium A passes through the fixing unit 20, and the recording medium A on which the color toner image is fixed is discharged to the discharge tray unit 22. Is done.
[0056]
Here, during such printing, the polygon mirror 62 of the optical scanning device 4 rotates at a high speed, so that the polygon mirror 62 has heat. Furthermore, when the polygon mirror 62 rotates at a high speed, a high-temperature airflow is generated inside the closed space S. The heat generated in this way is transmitted to the fθ lenses 24 and 25 by the first housing 43. At this time, since the first housing 43 is formed of a material having a higher thermal conductivity than the material of the fθ lenses 24 and 25, the heat generated by the rotation of the polygon mirror 62 as described above efficiently dissipates the fθ lens 24. , 25. Thereby, it is possible to prevent a temperature deviation from occurring in the fθ lenses 24 and 25. Therefore, it is possible to prevent the magnification deviation in the main scanning direction in the fθ lenses 24 and 25 from occurring.
[0057]
Further, since the material of the first housing 43 is a material having a higher thermal conductivity than the material of the second housing 44, the heat generated by the rotation of the polygon mirror 62 is efficiently transmitted to the second housing 44. As a result, the heat can be efficiently transmitted to each part of the optical scanning device 4, and the occurrence of a temperature deviation in the entire optical scanning device 4 can be prevented.
[0058]
Further, since the material of the first housing 43 is a metal and the material of the fθ lenses 24 and 25 is a resin that can be injection-molded, for example, the material of the first housing 43 is carbon having a higher thermal conductivity than the resin. The cost of the optical scanning device 4 can be reduced as compared with a case where flaffite or the like is used or a case where glass is used as a material of the fθ lenses 24 and 25. Further, since the material of the second housing 44 is a resin, injection molding can be performed, so that the cost of the optical scanning device 4 can be further reduced.
[0059]
In addition, since the first housing 43 and the second housing 44 have different coefficients of linear expansion, when the heat is generated by the rotation of the polygon mirror 62, the heat generated between the first housing 43 and the second housing 44. A difference occurs in the coefficient of expansion. At this time, for example, when the second fitting portion is a fitting having no play, the first housing 43 and the second housing In this embodiment, the second fitting portion 54 slides in the direction b in which the second fitting portion 54 comes into contact with and separates from the first fitting portion 53 and the cylindrical portion 55 slides into the first hole 56. Since the play fit has a play in the direction a, the thermal expansion between the first housing 43 and the second housing 44 is not restricted by the second engaging portion, and the first housing 43 The second housing 44 can be thermally expanded; It is possible to prevent the distortion occurs to one of the housing 43 and the second housing 44. Thereby, it is possible to prevent the positional accuracy of the fθ lenses 24 and 25 from deteriorating. In addition, it is possible to prevent the imaging performance of the fθ lenses 24 and 25 from deteriorating, and it is possible to improve the accuracy of the spot diameter of the light beam L that forms an image on the photoconductor 6.
[0060]
Further, since the openings 49 and 50 for exposing the inside of the second housing 44 are formed in the second housing 44, the heat from the polygon mirror 62 is released from the openings 49 and 50 and the optical scanning device is provided. 4 The temperature rise of the whole is suppressed. Thus, the temperature deviation of the fθ lenses 24 and 25 can be prevented, the temperature rise of the fθ lenses 24 and 25 can be suppressed, and the magnification of the entire fθ lenses 24 and 25 can be stabilized.
[0061]
In addition, since the heat from the polygon mirror 62 is released to the outside of the second housing 44 by the fins 51 and 52, the temperature rise of the entire optical scanning device 4 is further suppressed. Thereby, the temperature deviation of the fθ lenses 24 and 25 can be prevented, the temperature rise of the fθ lenses 24 and 25 can be more effectively suppressed, and the magnification of the entire optical element can be further stabilized. The heat radiation effect of the fins 51 and 52 can be further improved by providing a fan for forcing the fins 51 and 52 against the outside air.
[0062]
As described above, in the present embodiment, since the temperature deviation and the magnification deviation are prevented from occurring in the fθ lenses 24 and 25, the relative positions of the plurality of light beams L can always be stably maintained. Further, since a temperature deviation and a magnification deviation are prevented from occurring in the fθ lenses 24 and 25, a magnification change in an image formed on the recording medium A can be prevented. In addition, it is possible to prevent the light beams L on the photoconductor 6 from overlapping, thereby preventing the color of an image from changing.
[0063]
【The invention's effect】
According to the optical scanning device of the first aspect, a light source that emits a light beam based on image information, a deflecting unit that is driven to rotate and deflects the light beam emitted from the light source, and is deflected by the deflecting unit An optical element for converting the converted light beam from constant angular velocity scanning light to constant velocity scanning light, and a first element formed of a material having a higher thermal conductivity than the material of the optical element and supporting the deflecting unit and the optical element With this configuration, the heat generated in the deflecting unit is efficiently transmitted to the optical element, so that it is possible to prevent a temperature deviation from occurring in the optical element. This can prevent a magnification deviation from occurring in the main scanning direction.
[0064]
According to the invention described in claim 2, in the optical scanning device according to claim 1, the material of the first housing is a metal, and the material of the optical element is a resin. Cost can be reduced.
[0065]
According to the third aspect of the present invention, in the optical scanning device according to the first or second aspect, any one of the second housing that supports the first housing, and the first housing and the second housing. A first hole provided in one of the first housing and a first fitting piece provided in one of the other of the first housing and the second housing; A first fitting portion in which a first fitting piece is slidably fitted, a second hole provided in one of the first housing and the second housing, A first housing and a second fitting piece provided on one of the other of the second housing, wherein the second hole and the second fitting piece are the first positioning pieces. Play in the direction in which the first fitting piece slides into and out of the first hole. A second fitting portion which is loosely fitted with the first housing, and the first housing and the second fitting portion perform positioning of the first housing and the second housing. Therefore, even when the first housing and the second housing have different coefficients of linear expansion, when the heat is generated in the deflecting portion, the heat of the first housing and the second housing is reduced. The expansion is not restricted by the second fitting portion, and it is possible to prevent the first housing and the second housing from being distorted. As a result, it is possible to prevent the position accuracy of the optical element from being deteriorated, and it is possible to prevent the imaging performance of the optical element from being deteriorated.
[0066]
According to the fourth aspect of the present invention, in the optical scanning device according to the third aspect, the material of the first housing has a higher thermal conductivity than the material of the second housing, so that the material is generated in the deflection unit. The generated heat can be efficiently transmitted to the second housing.
[0067]
According to the fifth aspect of the present invention, in the optical scanning device according to the fourth aspect, since the material of the second housing is a resin, the cost of the optical scanning device can be reduced.
[0068]
According to a sixth aspect of the present invention, in the optical scanning device according to the first, second, third, fourth, or fifth aspect, a cover for covering each part of the device is provided, and the cover has an opening for exposing the inside of the cover. By having the portion, the heat is released from the opening, so that the temperature rise of the entire optical scanning device can be suppressed, whereby the occurrence of temperature deviation of the optical element can be prevented. The temperature rise of the element can be suppressed, and the magnification of the entire optical element can be stabilized.
[0069]
According to the seventh aspect of the present invention, in the optical scanning device according to the sixth aspect, the first housing has a fin formed to protrude from the opening to the outside of the cover to perform heat radiation, so that heat is released. Is released from the fins, it is possible to suppress an increase in the temperature of the entire optical scanning device, thereby preventing a temperature deviation of the optical element from occurring, and effectively reducing the temperature increase of the optical element. Therefore, the magnification of the entire optical element can be further stabilized.
[0070]
According to an eighth aspect of the present invention, in the optical scanning device according to the first, second, third, fourth, fifth, sixth, or seventh aspect, a plurality of the light sources and the plurality of optical elements are provided, and a plurality of the optical elements are provided. The elements can prevent a temperature deviation and a magnification deviation from occurring in each of the plurality of optical elements by converting the different light beams from the constant angular velocity scanning light to the constant velocity scanning light. It is possible to prevent the relative positions of the light beams from changing.
[0071]
According to the image forming apparatus of the ninth aspect, the image carrier, a charging section for charging the image carrier, and exposure scanning of the surface of the image carrier to form an electrostatic latent image on the surface. An optical scanning device according to claim 1, a developing unit that develops the electrostatic latent image with toner to form a toner image, and a transfer unit that transfers the toner image to a recording medium. By providing the same, the same operation and effect as the invention according to any one of claims 1 to 8 can be obtained. As a result, a change in magnification in an image formed on the recording medium can be prevented. When a plurality of light sources are provided, it is possible to prevent light beams from overlapping on the image carrier, thereby preventing a change in color of an image.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional front view schematically showing a laser printer according to an embodiment of the present invention.
FIG. 2 is a vertical sectional front view schematically showing an optical scanning device.
[Explanation of symbols]
1 laser printer (image forming device)
4 Optical scanning device
5 Intermediate transfer belt (transfer section)
6 (6Y, 6C, 6M, 6B) Photoconductor (image carrier)
6a Outer peripheral surface (surface)
7 Charging part
8 Developing section
19 Intermediate transfer roller (transfer section)
24, 25 fθ lens (optical element)
43 First Housing
44 Second housing, cover
49,50 opening
51,52 fin
53 First fitting part
54 Second fitting part
55 cylindrical part (first fitting piece)
56 First Hole
57,58 slot (second hole)
59,60 stepped screw (second fitting piece)
62 Polygon mirror (deflection unit)
A Recording medium
L (L1, L2, L3L4) light beam

Claims (9)

A light source that emits a light beam based on image information;
A deflecting unit that rotates and deflects a light beam emitted from the light source,
An optical element that converts the light beam deflected by the deflecting unit from constant angular velocity scanning light to constant velocity scanning light,
A first housing formed of a material having a higher thermal conductivity than the material of the optical element and supporting the deflection unit and the optical element,
An optical scanning device comprising: The material of the first housing is metal,
The optical scanning device according to claim 1, wherein a material of the optical element is a resin. A second housing supporting the first housing;
A first hole provided in one of the first housing and the second housing, and a first fitting provided in one of the other of the first housing and the second housing Having a mating piece, a first fitting portion in which the first fitting piece is slidably fitted in the first hole,
A second hole provided in one of the first housing and the second housing, and a second fitting provided in the other of the first housing and the second housing Having a mating piece, wherein the second hole and the second fitting piece are in contact with and separated from the first positioning portion and slide the first fitting piece into the first hole. A second fitting portion that is loosely fitted with play in the direction,
With
3. The optical scanning device according to claim 1, wherein positioning of the first housing and the second housing is performed by the first fitting portion and the second fitting portion. 4. The optical scanning device according to claim 3, wherein a material of the first housing has a higher thermal conductivity than a material of the second housing. The optical scanning device according to claim 4, wherein a material of the second housing is a resin. A cover that covers each part of the device,
The optical scanning device according to claim 1, wherein the cover has an opening that exposes the inside of the cover. The optical scanning device according to claim 6, wherein the first housing includes a fin formed to protrude from the opening to the outside of the cover to perform heat radiation. The light source and the optical element are provided in plurality, respectively.
The optical scanning device according to claim 1, wherein the plurality of optical elements convert the different light beams from constant angular velocity scanning light to constant velocity scanning light. An image carrier;
A charging unit for charging the image carrier,
9. The optical scanning device according to claim 1, wherein the surface of the image carrier is exposed and scanned to form an electrostatic latent image on the surface.
A developing unit that develops the electrostatic latent image with toner to form a toner image;
A transfer unit for transferring the toner image to a recording medium,
An image forming apparatus comprising:

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