JP2008070681A - Optical scanning device and image forming apparatus using optical scanning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner in which the bend and its variation of scanning line occurring by the nonuniform temperature rise of optical elements in an optical housing due to the heat generation caused by the rotation of a rotating polygon mirror are suppressed as much as possible, and to provide an image forming apparatus using the optical scanner. <P>SOLUTION: The optical scanner is composed of: a light source; a deflector which deflects a luminous flux from the light source; image-forming optical elements which forms an image of the deflected luminous flux as a light spot on a face to be scanned; and a housing 203 which houses the above described components, wherein the material constituting the housing 203 is composed of a resin, and at least one image-forming optical element 201 out of the image-forming optical elements is arranged in the housing 203 via a sheet 204. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical scanning device that scans a surface to be scanned with a light spot formed by deflecting and converging a light beam from a light source, and a light applied to a digital copying machine, an optical printer, an optical facsimile, an optical plotter, and the like. The present invention relates to an image forming apparatus using a scanning device, and more particularly to a multicolor image forming apparatus that forms a color image by superimposing toner images of a plurality of colors.

  The light beam from the light source is deflected by the light deflecting means of the rotary polygon mirror, and the deflected light beam is condensed toward the scanned surface by using a scanning imaging optical system such as an fθ lens. 2. Description of the Related Art An optical scanning device that forms a light spot and scans a surface to be scanned with the light spot is widely known in connection with image forming apparatuses such as an optical printer, an optical plotter, and a digital copying machine.

  In an image forming apparatus using an optical scanning device, an image writing step of writing an image by optical scanning is adopted as one step in the image forming process. It is affected by the quality of optical scanning. The quality of optical scanning depends on the scanning characteristics of the optical scanning device in the main scanning direction and the sub-scanning direction.

  One of the scanning characteristics in the main scanning direction is scanning isokineticity. For example, when a rotating polygon mirror is used as the light deflecting means, the light beam is deflected at an equiangular velocity. Therefore, a scanning imaging optical system with a corrected fθ characteristic is used in order to realize scanning constant velocity. Yes.

  However, due to the relationship with other performances required for the scanning imaging optical system, it is not easy to completely correct the fθ characteristic. For this reason, in an actual scanning optical system, optical scanning is not performed at a uniform speed, and the constant speed as the scanning characteristic is accompanied by a deviation from the ideal constant speed scanning.

  The scanning characteristics in the sub-scanning direction include scanning line bending and scanning line inclination. The scanning line is the movement locus of the light spot on the surface to be scanned and is ideally a straight line, and the optical scanning device is designed so that the scanning line is a straight line. In general, a scanning line is bent due to a part processing error or an assembly error.

  When an imaging mirror is used as the scanning imaging optical system and an angle is set in the sub-scanning direction between the incident direction of the “deflected beam” to the imaging mirror and the reflection direction, in principle, the scanning line is used. Even when the scanning imaging optical system is configured as a lens system, the scanning line is inevitably bent by the multi-beam scanning method in which the scanning surface is scanned with a plurality of light spots separated in the sub-scanning direction. is there.

  The inclination of the scanning line is a phenomenon in which the scanning line is not orthogonal to the sub-scanning direction, and is a kind of bending of the scanning line. Therefore, in the following description, unless otherwise specified, the inclination of the scanning line is included in the expression of scanning line bending.

  If the image is so-called monochrome and is formed by writing with a single optical scanning device, scanning line bending and constant velocity imperfections (deviation from ideal constant velocity scanning) can be suppressed to some extent. Although the “formed distortion” is not generated in the formed image, the distortion of such an image is never small.

  Separately from a monochrome image, three colors of magenta, cyan, and yellow, or four colors with black added thereto, are formed as color component images, and a color image is formed by superimposing these color component images. Conventionally, color copying machines and the like have been used.

  As one method for forming such a color image, there is an image forming method called a tandem type in which an image for each color component is formed on a photoconductor for each color component. In the case of such an image forming method, if the scanning position of the optical scanning device varies with respect to the photosensitive member, and the scanning line is bent or tilted differently, an abnormal image called “color shift” appears in the formed color image. Degrading the image quality of color images.

  As a means for reducing the bending and inclination of the scanning line as an optical scanning device, the long lens is bent with a plurality of supporting points as supporting points, or tilted in the sub-scanning direction to correct the scanning line bending and the scanning line inclination. A configuration has been proposed (see, for example, Patent Document 1).

  As a method for reinforcing an optical element, an example in which a reinforcing plate made of a glass material is attached to the back surface of a mirror with a damping member is disclosed (for example, see Patent Document 2), and an example in which a plate glass is bonded to the side surface of a lens. Is disclosed (for example, see Patent Document 3).

  As a measure against the heat inside the optical housing, a proposal has been made to cool the housing by providing a heat radiating duct (see, for example, Patent Document 4).

  In an image forming apparatus using the Carlson process, latent image formation, development, and transfer are performed according to the rotation of the photosensitive drum. Therefore, in a multicolor image forming apparatus in which a plurality of photosensitive drums are arranged along the transfer direction of the transfer body and the toner images formed at the image forming stations of the respective colors are overlaid, the latent images due to the eccentricity of the photosensitive drums and the variation in the diameter are reduced. Due to differences in registration time in the sub-scanning direction of each toner image due to variations in the time between image formation and transfer, the difference between the photosensitive drums of each color, the speed fluctuation or meandering of the transfer body, for example, a transfer belt or a conveyance belt for conveying recording paper The image quality deteriorates due to color shift or color change.

  Similarly, in the optical scanning device, if the main scanning magnification and the writing position of the electrostatic latent image formed on the photosensitive drum are not accurately matched, color misregistration and color change may be caused by registration misregistration.

  Conventionally, this registration deviation is detected periodically at the start-up of the apparatus or between jobs by the registration deviation detection pattern recorded on the transfer body, regardless of whether it is due to the optical scanning apparatus or other than the optical scanning apparatus. For the scanning direction, the position of the leading line is corrected by matching the timing of writing every other surface of the polygon mirror, and for the main scanning direction, writing is performed by adjusting the timing from the synchronization detection signal generated at the scanning start end. While correcting the position, the full width magnification between the colors is adjusted by adjusting the frequency of the pixel clock by detecting the scanning time from the scanning start end to the scanning end (see, for example, Patent Documents 5, 6, 7, and 8). ).

  On the other hand, in such a multicolor image forming apparatus, speeding up and density increase are progressing year by year. As a countermeasure, there is a method to increase the rotation speed of the polygon motor. However, since the bearing life is limited and heat and vibration cannot be suppressed, it is possible to scan multiple beams simultaneously at a lower rotation speed. A method using a multi-beam light source capable of realizing high speed and high density has been proposed.

However, since the multi-beam light source has a pitch error and a wavelength difference between the light sources, an example of avoiding a shift between the light sources by individually detecting a registration shift with a plurality of lines as a set has been proposed (for example, (See Patent Document 7).
JP 2002-258189 A Japanese Patent Laid-Open No. 11-142767 JP 2000-241733 A JP 2001-337291 A Japanese Patent Publication No.7-19084 JP 2001-253113 A JP 2003-154703 A Japanese Unexamined Patent Publication No. 9-58053

  In recent years, in order to improve scanning characteristics, it has become common to adopt special surfaces typified by aspherical surfaces in the imaging optical system of optical scanning devices, and such special surfaces can be easily formed. An imaging optical system made of a resin material that can be manufactured at a low cost is often used.

  An imaging optical system made of a resin material is susceptible to changes in temperature and humidity due to changes in temperature and humidity, and such changes in optical characteristics also change the degree of scanning line bending and the constant velocity. For this reason, for example, when several tens of color images are continuously formed, the in-machine temperature rises due to the continuous operation of the image forming apparatus, and accordingly, the optical element receiving surface of the optical housing due to the temperature rise in the optical writing apparatus. Due to the deterioration of the position accuracy, the beam position with respect to the optical element is changed, or the installation angle of the folding mirror is changed, thereby causing a problem that the scanning position on the photosensitive member is shifted with time.

  As a result, the optical characteristics of the imaging optical system change, and the bend and constant velocity of the scanning line written by each optical writing device gradually change, resulting in color misregistration caused by the misregistration of the scanning position. The color image obtained is completely different from the color image obtained in the final stage.

  In addition, the optical element may be distorted due to the difference in linear expansion coefficient between the housing and the optical element. As shown in FIG. 19A, when the optical element 201 is installed in the housing 203 by the projection 202, the inside of the housing is warmed by heat generated by a rotating polygon mirror or the like, and the linear expansion coefficient between the optical element 201 and the housing 203 is increased. If the linear expansion coefficient of the optical element 201 is larger than the linear expansion coefficient of the housing 203, the optical element 201 is fixed to the housing 203 by the projection 202 as shown in FIG. The element 201 is deformed, affects the sub-scanning direction, changes the scanning line curve, and degrades the image performance.

  In addition, the heat generated by the rotating polygon mirror is transmitted through the housing, and is transmitted from the portion in contact with the housing to the optical element, resulting in a non-uniform temperature distribution within the optical element, resulting in a non-uniform refractive index distribution of the optical element, which affects the beam spot diameter. Effect.

  FIG. 20 shows how heat from the housing 203 is transferred to the optical element 201. The optical element 201 is disposed in the housing 203 by a protrusion 202 provided on the optical element 201. When the optical element 201 is disposed in the housing 203, by reducing the area in contact with the projection 202, the area for guaranteeing the positional accuracy is reduced, and the cost of components is reduced. Heat generated by the rotary polygon mirror is transmitted through the housing 203 and the protrusion 202 and reaches the optical element 201. The optical element 201 is warmed from the part in contact with the protrusion 202, and the non-uniform temperature distribution in the optical element 201 causes the non-uniform refractive index distribution to affect the beam spot diameter, resulting in white streaks on the image. Affects quality.

  A scanning imaging lens such as an fθ lens that is representative of a scanning optical system is generally formed as a strip-shaped lens that is long in the main scanning direction by cutting a lens unnecessary portion (portion where no deflected light beam is incident) in the sub-scanning direction. When the scanning imaging lens is composed of a plurality of lenses, the lens length in the main scanning direction increases as the arrangement position is further away from the light deflecting unit, and the length is about 100 mm to 250 mm or more. A lens is required. Such a long lens is generally formed by resin molding using a resin material. However, if the temperature distribution in the lens becomes non-uniform due to a change in the external temperature, the lens is warped and the lens is bowed in the sub-scanning direction. It becomes. Such warpage of the long lens causes the scanning line bending described above.

  In order to deflect and scan a light beam emitted from a light source, the optical scanning device rotates a polygonal mirror having a plurality of reflecting surfaces as a rotating polygonal mirror, and optically scans the surface to be scanned.

  For this reason, the rotating polygon mirror generates heat, and the optical housing (optical housing) that accommodates each optical element constituting the optical scanning device based on the heat causes thermal deformation, and the tilt angle of the mirror disposed therein ( The tilt angle with respect to the direction orthogonal to the deflection scanning plane and the position of the scanning optical element (imaging lens or imaging mirror) change in the direction orthogonal to the deflection scanning plane (sub-scanning direction), and on the surface to be scanned. The scanning line bending of the beam that scans.

  As a method for solving the problem with respect to the deformation of the optical housing, a method as described in the prior art has been proposed. However, as a means for reducing the deformation of the optical housing, the one disclosed in Japanese Patent Application Laid-Open No. 2001-228426 takes into account the deformation of the housing, but the internal optical element (change in the tilt angle of the mirror, (Position fluctuation of the optical element) is not taken into consideration, and it cannot cope with a change in the arrangement position of the optical element due to a temperature change.

  Japanese Patent Application Laid-Open No. 2005-257825 proposes a structure in which a light source portion is placed on a base member to expose a part of the base member to the outside of the optical housing and dissipate heat. In this example, the heat generation of the light source unit is considered, but the countermeasure for the heat generation of the rotary polygon mirror having the largest heat generation amount in the optical housing is not considered.

  As an example of an optical scanning device corresponding to a multicolor image forming apparatus, as disclosed in Japanese Patent Laid-Open No. 2002-148551, a light beam from a light source corresponding to each color is scanned collectively by a single polygon mirror. In this way, a configuration in which a plurality of folding mirrors for guiding to corresponding scanning optical systems and photosensitive drums are integrally supported by a common optical housing, and an optical scanning device individually corresponding to each photosensitive drum. The deployed configuration is known. As described above, since the components are arranged so that the light beams traveling toward the photosensitive drum pass through different paths, the scanning position of each light beam easily varies depending on the environmental temperature where the multicolor image forming apparatus is installed. Resulting in.

  Scanning position deviations are periodically detected and corrected at the start-up of the apparatus and between jobs using the registration deviation detection pattern recorded on the transfer body. Since the irradiation position further varies due to heat from the motor, etc., there is a problem that color misregistration and color change gradually occur when the number of prints for one job is large.

  In particular, when an optical system is arranged so as to face each other with a polygon scanner interposed therebetween as in JP-A-2002-148551, since the scanning directions are opposite, the writing position is shifted due to fluctuations in the main scanning magnification, and the optical housing Due to this distortion, the scanning positions between the colors are shifted in the direction of increasing, so that color shift and color change are likely to occur.

As a countermeasure, if the temperature change reaches a predetermined value by constantly observing the temperature, or if the predetermined number of prints is exceeded, the printing operation is stopped halfway and the deviation of the irradiation position is corrected again. However, taking into consideration the registration deviation detection pattern creation to correction, and the detection pattern creation to correction check again, it takes several minutes to complete, and productivity is reduced, and toner is wasted to form detection patterns. I want to keep the frequency of correction to a minimum.
The present invention has been made paying attention to the above problems, and scanning line bending caused by uneven temperature rise of the optical element in the optical housing due to the amount of heat generated with the rotation of the rotating polygonal mirror and its fluctuation, It is an object of the present invention to provide an optical scanning device and an image forming apparatus using the optical scanning device that are suppressed as much as possible.

In order to achieve the above object, the invention according to claim 1 provides:
A light source;
A deflector for deflecting the light beam from the light source;
An imaging optical element that forms an image of the deflected light beam as a light spot on the surface to be scanned;
In an optical scanning device comprising a housing containing the above,
The material constituting the housing is made of resin,
At least one imaging optical element among the imaging optical elements is disposed in the housing via a sheet.

In invention of Claim 2,
The optical scanning device according to claim 1,
The sheet is a heat insulating sheet.

In invention of Claim 3,
The optical scanning device according to any one of claims 1 to 2,
The imaging optical element is fixed to the housing by a protrusion provided on the imaging optical element,
A sheet is disposed between the surface of the imaging optical element provided with the protrusion and the housing,
The thermal conductivity of the sheet is set to have a small difference from the thermal conductivity of the imaging optical element.

In invention of Claim 4,
The optical scanning device according to any one of claims 1 to 2,
The imaging optical element is fixed to the housing by a protrusion provided on the imaging optical element,
A sheet is disposed between the surface of the imaging optical element provided with the protrusion and the housing,
The thermal conductivity of the sheet is characterized in that the difference from the thermal conductivity of the housing is set small.

In invention of Claim 5,
The optical scanning device according to any one of claims 1 to 4,
Beam spot position deviation detecting means;
Based on the detection result from the beam spot position deviation detection means, the position deviation correction control means for controlling the attitude of the imaging optical element and correcting the beam spot position deviation;
It is provided with.

In invention of Claim 6,
The optical scanning device according to any one of claims 1 to 5,
The light source is a multi-beam optical scanning device having a plurality of light emitting points and scanning a surface to be scanned with a plurality of light beams simultaneously.

In invention of Claim 7,
An electrostatic latent image is formed on the image carrier by an optical scanning device, the electrostatic latent image is developed, and the image formed on the image carrier is transferred to a sheet-like recording medium carried on the transfer member. In an image forming apparatus that obtains an image by
The optical scanning device according to any one of claims 1 to 6 is used as the optical scanning device.

In invention of Claim 8,
The image forming apparatus using the optical scanning device according to claim 7,
The image forming apparatus is a color image forming apparatus that has a plurality of image carriers, develops an electrostatic image formed on the image carrier with each color toner, and superimposes them on a transfer member to form a color image. It is characterized by.

In invention of Claim 9,
The image forming apparatus using the optical scanning device according to claim 8.
Color misregistration detection means;
Color misregistration correction control means for controlling the attitude of the imaging optical element based on the detection result from the color misregistration detecting means and performing color misregistration correction;
It is provided with.

In invention of Claim 10,
An image forming apparatus using the optical scanning device according to any one of claims 7 to 9,
The image forming apparatus has a network communication function.

  5. The optical scanning device according to claim 1, wherein a temperature rise of the optical element in the optical housing due to the amount of heat generated with the rotation of the rotary polygon mirror, and a scanning line bend caused by deformation of the optical housing. , And fluctuations in scanning line bending can be reduced.

  In the optical scanning device according to the fifth aspect, the beam spot position deviation can be corrected and the image quality can be improved.

  In the optical scanning device according to claim 6, by scanning the surface to be scanned simultaneously with a plurality of light beams, the rotational speed of the deflector is reduced, the power consumption by the deflector is reduced, and the heat generation amount is reduced. It is done.

  In the image forming apparatus using the optical scanning device according to claim 7, an irradiation position deviation correction step (registration deviation detection pattern creation to correction) is performed as a countermeasure against color deviation and color change occurring in a job. It is possible to reduce the number of times of performing detection pattern creation to correction check again. As a result, productivity can be improved and the number of detection pattern formations can be reduced, so that the number of times the toner is consumed by the shift correction process can be reduced. Therefore, power consumption can be reduced and consumption of consumables can be reduced (environmental support).

  In the image forming apparatus using the optical scanning device according to any one of claims 8 to 9, a color image forming apparatus with little color misregistration can be formed.

  In the image forming apparatus using the optical scanning device according to the tenth aspect, an information processing system capable of processing outputs from a plurality of devices can be formed by having a network communication function.

  The best mode for realizing an optical scanning device and an image forming apparatus using the optical scanning device of the present invention will be described below based on a first embodiment shown in the drawings.

  Fig. 1 shows an embodiment of an optical scanning device that scans 4 stations. Opposite scanning system that divides the beam into 2 stations, divides the beam into the opposite direction of a single polygon mirror, and deflects and scans in opposite directions. Indicates. The four photosensitive drums 101, 102, 103, and 104 are arranged at equal intervals along the moving direction 105 of the transfer member, and sequentially transfer and superimpose different color toner images to form a color image.

  As shown in FIG. 1, the optical scanning device that scans each photosensitive drum is integrally configured, and scans the light beam with the polygon mirror 106. Since the rotation direction of the polygon mirror 106 is the same, the scanning direction is the opposite direction on the opposite side, and the image is written so that one writing position and the other writing end position coincide. Each component constituting the optical scanning device is placed on a housing (optical housing) (not shown).

  In the first embodiment, a pair of semiconductor lasers are provided for each photoconductor, and scanning is performed by shifting one line pitch in the sub-scanning direction in accordance with the recording density so that two lines are simultaneously scanned. The beams B1, B2, B3, and B4 from each light source unit are arranged at portions where the emission positions differ in the sub-scanning direction for each light source unit. In the first embodiment, the emission positions of the light source units 107, 108, 109, and 110 are predetermined. They are deployed to differ in height (for example, 6mm). The beams from the light source units 108 and 109 are turned back by the incidence mirrors 111 and 112, and are incident on the polygon mirror 106 with the main scanning direction approaching the beams from the light source units 107 and 110 directly toward the polygon mirror 106.

  The cylinder lenses 113, 114, 115, and 116 are arranged such that one has a common curvature in the plane and the other in the sub-scanning direction, and the optical path lengths to the deflection reflection points of the polygon mirror 106 are equal. Each light beam is converged so as to be linear in the main scanning direction on the deflecting surface, and in the sub-scanning direction on the deflection reflection point and on the surface of the photosensitive member by a combination of an imaging optical system composed of an fθ lens and an anamorphic lens described later. The surface tilt correction optical system is formed by using the conjugate relationship in FIG.

  The optical axis changing units 117, 118, and 119 are provided in stations other than the reference color (in the first embodiment, other than the beam from the light source unit 109) and stably hold (correct) the scanning position of each light beam.

  The polygon mirror 106 is a six-sided mirror and is configured in two stages in the first embodiment, and a windage is reduced by providing a groove so that the intermediate portion not used for deflection is slightly smaller in diameter than the inscribed circle of the polygon mirror 106. It has a shape. The thickness of one layer is about 2 mm. Note that the phases of the upper and lower polygon mirrors are the same.

  The fθ lenses 120 and 121 are also integrally formed or joined in two layers, and each has a non-circular arc in the main scanning direction with power so that the beam moves at a constant speed on the surface of the photosensitive member as the polygon mirror rotates. An imaging optical system is formed by the anamorphic lenses 122, 123, 124, and 125 provided for each beam, and has a surface shape. Each beam is imaged in a spot shape on the surface of the photoconductor, and a latent image is recorded. .

  In each color station, a plurality of sheets are used so that the respective optical path lengths from the polygon mirror 106 to the surface of the photoconductor coincide with each other, and the incident positions and incident angles with respect to the photoconductor drums arranged at equal intervals are equal. In 1, there are three folding mirrors per station.

  Explaining the optical path for each color station, the beam B1 from the light source unit 107 is deflected at the upper stage of the polygon mirror 106 via the optical axis changing means 117 and the cylinder lens 113, and then passes through the upper layer of the fθ lens 120. Then, it is reflected by the folding mirror 126, passes through the anamorphic lens 122, is reflected by the folding mirrors 127, 128, and is guided to the photosensitive drum 102 to form a magenta image as the second station.

  The beam B2 from the light source unit 108 is reflected by the incident mirror 111 via the optical axis changing means 118 and the cylinder lens 114, is deflected at the lower stage of the polygon mirror 106, passes through the lower layer of the fθ lens 120, and is turned back. The light is reflected by 129, passes through the anamorphic lens 123, is reflected by the folding mirrors 130 and 131, and is guided to the photosensitive drum 101 to form a yellow image as the first station.

  The same applies to opposing stations arranged symmetrically to the polygon mirror 106. The beam B3 from the light source unit 109 is deflected at the lower stage of the polygon mirror 106 via the incident mirror 112 and reflected by the folding mirrors 132, 133, and 134. As a fourth station, the black image is guided to the photosensitive drum 104, and the beam B4 from the light source unit 110 is deflected by the upper stage of the polygon mirror 106 and reflected by the folding mirrors 135, 136, and 137. It is guided to the photosensitive drum 103 and forms a cyan image as a third station.

FIG. 2A shows a view in which a sheet 204 is disposed between a projection 202 of an optical element 201 (imaging optical element) that forms an image of a deflected light beam as a light spot on a surface to be scanned and a housing 203. .
The sheet 204 is an elastic member that is more flexible than the optical element 201 and the housing 203. For example, a rubber member, a low-curing adhesive (such as a silicone-based flexible adhesive, or a thermosetting adhesive as an epoxy) By using a base adhesive and heating it below the curable temperature of the thermosetting adhesive, the resin flexibility of the thermosetting adhesive is slightly improved after curing, and the thermosetting adhesive is easily deformed. Therefore, it is possible to easily absorb distortion such as thermal deformation).

  FIG. 2B shows the state of the optical element 201 and the housing 203 during heat generation. When the optical element 201 and the housing 203 have different linear expansion coefficients due to heat generation, the optical element 201 expands larger than the housing 203 when the optical element 201 has a large linear expansion coefficient, but the sheet 204 is deformed to deform the optical element 201 and the housing. The difference in expansion of 203 is absorbed, and the optical element 201 is not bent in the sub-scanning direction (claim 1).

  FIG. 3 shows a view in which a heat insulating sheet 204 is disposed between the projection 202 of the optical element 201 and the housing 203. As the heat insulating sheet 204, for example, resin mixed with glass fiber, asbestos, rock wool, a bag sealed with a liquid, a member having low thermal conductivity, or the like can be used. The heat from the housing 203 is not directly transferred to the optical element 201 by the heat insulating sheet 204 (Claim 2).

  When the protrusions 202 provided on the optical element 201 are arranged as shown in FIG. 5, the sheet 204 through which the position corresponding to the protrusions 202 penetrates as shown in FIG. The protruding portion 202 of the element 201 is passed through a hole formed in the sheet 204, and the optical element 201 is disposed in the housing 203.

  When the difference between the thermal conductivity of the sheet 204 and the thermal conductivity of the optical element 201 and the protrusion 202 is small, the heat transferred from the housing 203 warms the optical element 201 evenly. At this time, the refractive index distribution of the optical element 201 is uniform, white streaks or the like do not occur on the image, and the image quality is not affected.

  Further, since the positional accuracy of the optical element 201 in the housing 203 is maintained in a small area of the projection 202, it is advantageous for reducing the cost of the optical element 201 (Claim 3).

  The same effect can be obtained when the difference between the thermal conductivity of the sheet 204 and the thermal conductivity of the housing 203 is small (claim 4).

FIG. 7 shows the configuration of the support housing of the anamorphic lens.
The anamorphic lens 305 is made of resin and has a rib portion 306 formed so as to surround the lens portion, and a positioning projection 307 is formed at the center portion.

  The support plate 301 is formed in a U shape with a sheet metal, and the protrusion 307 of the anamorphic lens 305 is engaged with the notch 311 formed in the vertical bending portion, and the lower surface of the rib is abutted against the vertical bending portion 310 and positioned. The pair of leaf springs 303 are biased from the upper surface of the rib to hold both ends. The leaf spring 303 is fitted from the outside in a state where the anamorphic lens 305 is superimposed on the support plate 301, and one end thereof is taken out from the opening 313 to be inserted into the opening 314 and fixed.

At the center, the adjustment screw 308 is screwed into the screw hole 312, the leaf spring 302 is similarly fitted from the outside, 317 and 318 are hooked inside the lower rib, and fixed in the same manner. The lower surface is urged so as to abut (see the cross-sectional view AA cut along AA in FIGS. 4 and 8).
In this way, the pressing force applied to the anamorphic lens 305 by the adjustment screw 308 and the elastic force applied by the leaf spring 302 work in opposite directions to enable delicate adjustment.

  The leaf spring hole 319 is a hole penetrating the adjustment screw 308. In the first embodiment, the adjusting screw 308 is similarly provided between the central portion and the lens end portion, but only the central portion may be provided.

FIG. 8 is a view of the anamorphic lens 305 mounted as seen from the optical axis direction.
The anamorphic lens 305 is supported at both ends by the edge of the vertical bending portion 310 and at the center by the adjustment screw 308. When the protruding amount of the adjustment screw 308 is insufficient for the vertical bending portion 310, the anamorphic lens generatrix 312 is on the lower side. Warps to become convex. On the other hand, if the protruding amount exceeds, it will warp upward. Therefore, by adjusting the adjusting screw, the focal line of the anamorphic lens is curved in the sub-scanning direction, and the bending of the scanning line can be corrected.

  In general, the bending of the scanning line is caused by an arrangement error of the optical element constituting the optical system, a warp at the time of molding, etc., and by correcting the linearity by curving the anamorphic lens 305 in a direction to cancel this, that is, The direction and amount of bending between the scanning lines can be made uniform.

  When the temperature inside the image forming apparatus changes, the anamorphic lens 305 expands or contracts. At this time, both ends of the anamorphic lens 305 are fixed by the spring force of the leaf spring 303, thereby preventing free expansion or expansion / contraction, and as a result, tensile stress or compression stress is generated. In the absence of the leaf spring 302, the anamorphic lens 305 is warped upward or downward by the generation of this stress, and the scanning line is bent in a quadratic curve.

  This is dealt with by a force acting between the leaf spring 302 and the adjusting screw 308. The pressing force acting on the anamorphic lens 305 by the adjusting screw 308 and the elastic force acting on the leaf spring 302 make the leaf spring 303 strong enough to counteract the occurrence of warp due to the tensile stress or compressive stress (overcoming the spring force of the leaf spring 303). By overcoming the frictional force generated in the above and assisting the expansion or contraction of the anamorphic lens 305, it is possible to suppress the occurrence of the above-mentioned quadratic scanning line curve.

  As another solution, the portion of the anamorphic lens 305 that contacts the leaf spring 303 may be made slippery to reduce the frictional force, thereby reducing the tensile stress or the compressive stress. This can be done by increasing the surface accuracy of the contact portion of the anamorphic lens 305, increasing the hardness, applying a lubricant, inserting a smooth member into the contact portion, etc. is there.

  Note that the above-mentioned adjusting screw can basically correct the scanning curve of a quadratic curve if it is provided at one central part, but it is provided at a plurality of locations along the main scanning direction, By deploying in a total of three places in between the part 310, the bending force of M type or W type may occur due to the pressing force and elastic force of the central part and the tensile stress or compressive stress due to the frictional force of both ends It is possible to correct the case.

  The support plate fitted with the anamorphic lens is positioned by fitting the protrusions 318 formed at the end into the 327 between the positioning guides 324 provided on the optical housing side, and biasing downward in the figure. The leaf spring 326 attached to the support portion 328 provided in the optical housing is bridged and supported. The end portions 320 and 323 of the support plate 301 and the positioning guides 324 and 325 have a shape along an arc centered on “O”, and are supported by the leaf spring 326 so that corresponding portions abut each other. .

  The stepping motor 315 is fixed to the optical housing, a feed screw formed at the tip of the shaft is screwed into the screw hole of the movable cylinder 316, and a notch 321 formed at one end of the support plate and a concave portion of the movable cylinder 316 are connected. By fitting, the sub-scanning direction (the height direction of the anamorphic lens) can be displaced by the rotation of the stepping motor 315. As a result, the anamorphic lens 305 can follow the forward / reverse rotation of the stepping motor 315 to adjust the rotation γ with “O” (see FIG. 8) as the rotation center within the plane orthogonal to the optical axis, and accordingly, the sub-scanning is performed. The generatrix of the anamorphic lens in the direction is tilted, and the scanning line as the imaging position after passing through the anamorphic lens is tilted (claim 5).

  In the first embodiment, the adjusting screw 308 is provided in all anamorphic lenses 305 including the fourth station serving as a reference, and the other stations are arranged so that the direction and amount of the scanning line curve serving as the reference are aligned at the time of manufacture. The above-described scanning lines are aligned, and the tilt adjustment described above can be performed while maintaining this state.

FIG. 9 is an enlarged view around the stepping motor of the scanning line inclination adjusting mechanism.
The shaft of the stepping motor 315 is provided with a nut portion that is threaded with a predetermined pitch and engages with the thread portion to form a spur gear on the outside. A differential screw portion is formed by meshing a spur gear integrally formed with the motor shaft and a two-stage gear and further meshing with a nut portion on which the spur gear is formed on the outside. Further, the upper and lower support portions are provided with bearing portions of the gear train, and the differential screw mechanism is configured integrally with the holding member.

  The differential screw mechanism is configured such that the motor shaft and the nut are rotated in the same direction by a gear train, and a difference in the number of teeth of the gear train is provided to cause a rotational phase difference between the motor shaft and the nut portion. Thus, a minute movement in the thrust direction is possible, and the resolution can be increased. Compared with a conventional adjustment resolution composed only of screws and nuts, an adjustment resolution of one digit or more can be obtained.

  In addition, the scanning line tilt adjustment mechanism is a two-shaft type stepping motor 315, with a single-sided screw, a spur gear mounted on one side, and a two-stage gear bearing that provides a phase difference between the screw and nut, and is integrated with the optical housing. Thus, space saving can be achieved.

  As shown in FIG. 1, substrates 138, 139 and 140, 141 on which photosensors are mounted are arranged on the scanning start side and scanning end side of the image recording area, and the scanned beams are detected at each station.

  In the first embodiment, the substrates 138 and 140 are used as synchronization detection sensors, and are shared so that the timing of starting writing is measured based on the detection signal.

  On the other hand, the substrates 139 and 141 serve as end detection sensors, detect a change in scanning speed by measuring a time difference between detection signals from the synchronous detection sensor, and detect each semiconductor laser in response to the detected change in scanning speed. By resetting the reference frequency of the pixel clock that modulates the image in inverse proportion, it is possible to stably maintain the full width magnification of the image recorded by each station on the transfer belt.

  Further, as shown in FIG. 11, a time difference Δt from the photodiode 152 to the photodiode 153 is measured by configuring one of the sensors with a photodiode 152 perpendicular to the main scanning direction and a non-parallel photodiode 153. Thus, the sub-scanning position shift Δy of the light beam can be detected.

The sub-scanning position deviation Δy is determined by using the inclination angle γ of the photodiode 153 and the scanning speed V of the light beam,
Δy ＝ (V / tanγ) ・ Δt
In the first embodiment, the irradiation position is controlled so that the sub-scanning resist of each color image does not shift by being held using an optical axis deflecting unit described later so that Δt is always constant. Can do.

  Further, if the sensor is arranged on both the scanning start side and the scanning end side, the difference in sub-scanning position deviation between the ends, that is, the inclination of the scanning line can be detected.

FIG. 11 shows a perspective view of the light source unit. All the light source units have the same configuration.
The semiconductor lasers 501 and 502 and the coupling lenses 503 and 504 are arranged symmetrically in the main scanning direction with respect to the emission axis for each color scanning unit, and the semiconductor lasers 501 and 502 are fitted to the outer periphery of the package, respectively. The members 505 and 506 are press-fitted from the back side, and are held in contact with the back surface of the holder member 507 by screwing screws through three points from the front side. The outer periphery is abutted against the V groove portions 508 and 509 formed so as to open in opposite directions, and are screwed inward by leaf springs 510 and 511. In the above example, the coupling lenses 503 and 504 may be bonded and fixed by an ultraviolet curable adhesive or the like although they are fixed by a leaf spring.

  At this time, the arrangement on the contact surface (surface orthogonal to the optical axis) of the base members 505 and 506 is set so that the light emitting points of the semiconductor lasers 501 and 502 are on the optical axis of the coupling lenses 503 and 504. The position on the V-groove (on the optical axis) is adjusted and fixed so that the light emitted from the coupling lenses 503 and 504 becomes a parallel light beam.

  The optical axes of the respective emitted lights are inclined so as to intersect with each other with respect to the emission axis C. In the first embodiment, the support member is inclined so that the intersection position is in the vicinity of the polygon mirror reflecting surface. ing.

  A printed circuit board 512 on which a drive circuit is formed is mounted on a pedestal erected on a holder member 507 with screws, and the lead terminals of the respective semiconductor lasers 501 and 502 are inserted into through holes and soldered, thereby light source units. 500 is constructed integrally.

  The light source unit 500 is positioned by inserting the cylindrical portion 513 of each holder member 507 into an engagement hole formed at a different height on the wall surface of the optical housing, and abutting the contact surface 514 to be screwed.

  At this time, the beam spot interval can be adjusted to the scanning line pitch P corresponding to the recording density by adjusting the tilt amount γ with the cylindrical portion as a reference.

Next, the operation of the write control circuit will be described with reference to FIG.
First, the pixel clock generation unit 401 counts the high frequency clock VCLK generated by the high frequency clock generation unit 402 in the counter 403, and the comparison circuit 404 sets in advance based on the count value and the duty ratio. Compares the value L and the phase data H given from the outside as the pixel clock transition timing and indicates the phase shift amount, and instructs the falling edge of the pixel clock PCLK when the count value matches the set value L When the control signal low coincides with the phase data H, the control signal h instructing the rise of the pixel clock PCLK is output. At this time, the counter 403 is reset simultaneously with the control signal h and starts counting from 0 again, whereby a continuous pulse train can be formed.
In this way, the phase data H is given for each clock, and the pixel clock PCLK whose pulse cycle is sequentially changed is generated.

In the first embodiment, the pixel clock PCLK is divided by 8 of the high-frequency clock VCLK so that the phase can be varied with a resolution of 1/8 clock.
FIG. 13 shows an example in which the phase is delayed by 1/8 clock. If the duty is 50%, the set value L = 3 is given, and the counter 403 counts four, and the pixel clock PCLK falls. If the 1/8 clock phase is delayed, phase data H = 6 is given, and it rises with 7 counts. At the same time, the counter is reset, so it falls again at 4 counts. In other words, the adjacent pulse period is shortened by 1/8 clock.

  The pixel clock PCLK generated in this way is supplied to the light source driving unit 405, and based on the pixel clock PCLK, the image data read by the image processing unit 406 is assigned to each pixel to generate modulation data, and the semiconductor laser is operated. To drive.

  By disposing the pixels that shift the phase at a predetermined interval in this way, it is possible to correct partial magnification error distortion along the scanning direction.

In the first embodiment, as shown in FIG. 14, the main scanning area is divided into a plurality of sections, and the interval and shift amount of the pixels for shifting the phase are set as shown below and given as phase data.
Now, assuming that the change in magnification with respect to the main scanning position x is L (x), the change M (x) in the beam spot position deviation is represented by the integral value.
M (x) = ∫L (x) dx
Assuming that the beam spot position deviation is corrected to 0 at the start and end points of the divided section, the deviation of the divided section width due to the change in the magnification of the arbitrary divided section is Δm, and the phase shift resolution is σ (constant) ), Where N is the number of pixels in the divided section, the interval between pixels for shifting the phase is
D≈N / (Δm / σ) However, D is an integer, and the phase may be shifted by σ for each D pixel. In the first embodiment, σ is 1/8 pixel. Therefore, in this case, the beam spot position residual is maximized at an exactly middle position of the divided sections. However, it is only necessary to determine each divided position and the number of divided sections so that the residual is within the allowable range.

  In general, the overlay accuracy of each color image is detected as a deviation from the reference station by reading the detection pattern of the toner image formed on the transfer belt 105, and the main scanning magnification, sub-scanning resist, and scanning line inclination. The correction control is performed periodically.

  Correction control is performed, for example, at the time of starting up the device or between jobs. When the number of prints for one job increases, it is corrected by interrupting in the middle to suppress deviation due to temperature changes during that time. Is applied.

  As shown in FIG. 1, the detection means includes an illumination LED element 154, a photosensor 155 that receives reflected light, and a pair of condenser lenses 156. The black, cyan, magenta, and yellow toner images are tilted approximately 45 ° from the main scanning direction to form a line pattern group called chevron patches arranged in parallel at a predetermined pitch. The difference in detection time from the reference color black is read.

  FIG. 15 shows an example, and the toner image on the detection line is read along the movement of the transfer body. The upper and lower sides of the paper correspond to the main scanning direction, and the theoretical values of the detection time differences tyk, tmk, tck from the reference color black by line patterns formed in order of yellow, magenta, cyan, black, cyan, magenta, yellow from the left. The deviation of the main scanning resist of each color is obtained from the difference between the sub-scanning resist of each color and the difference between the detection time differences tk, tc, tm and ty of a set of line patterns having different tilt angles.

  The inclination deviation of the scanning line is obtained from the sub-scanning resist difference between both ends, and is corrected by driving the inclination adjusting means of the anamorphic lens 305 described above (claim 9).

  The sub-scanning registration is obtained from the average of the respective detection values, and the writing timing in the sub-scanning direction is matched every other polygon mirror surface, that is, with one scanning line pitch P as a unit.

  Furthermore, since it is necessary to match the registration deviation with an accuracy of 1 scan line pitch P or less with the recent increase in quality required for color images, by finely adjusting the irradiation position using the optical axis changing means described later, Of the sub-scanning registration deviation detected by the toner image, an excess of one scanning line pitch P or less that cannot be corrected by the writing start timing can be corrected, and a reference value (initial value) of the irradiation position is set.

  On the other hand, between the pages, the photodiodes 152 and 153 are used as described above (see FIG. 10), and the difference from the reference value set based on the measured value accumulated during image recording is feedback-corrected. The reference value can be kept stable until the periodical correction time for the next toner patch. Note that the reference value does not need to be a constant value, and may be a value that periodically changes in response to a change in speed of the transfer body, for example.

  The main scanning magnification is obtained from the main scanning registration difference between both ends, and the reference frequency of the pixel clock for modulating each semiconductor laser and the timing from the synchronization detection signal are adjusted, thereby aligning the full width of the image and the writing position. Between pages, as described above, based on the detection time of the synchronization detection signal and the termination detection signal, always monitor the change in magnification, correct the reference frequency so that the full width does not change even if there is a temperature change, In order to prevent magnification distortion even at intermediate image heights, phase data weighted by predicting the magnification change for each divided section that accompanies a temperature change in advance corresponds to the variable amount of the full width magnification. Reading from the table is performed so that the magnification is uniform over the entire area in the main scanning direction.

  FIG. 16 shows the change of the magnification with respect to the temperature in each of the divided sections a to h, but changes in proportion to the change in the full width magnification, and can be distributed to the change in the magnification of each divided section based on the measurement value of the full width magnification.

  As described above, according to the first exemplary embodiment, in addition to the periodic correction based on the toner image detection, the variation in the job is monitored and the correction is performed between pages, so that the printing operation is not interrupted even during the job. Image overlay accuracy is maintained.

FIG. 17 is a perspective view of a liquid crystal deflecting optical element that is an optical axis changing means.
In the liquid crystal deflecting optical element, the orientation of the liquid crystal is changed by applying a potential difference between the upper and lower electrodes, and a refractive index distribution is generated as shown in the figure to bend the light beam.
As the optical axis changing means, in addition to such a liquid crystal deflection optical element, the same effect can be obtained by rotating a non-parallel plate or using a galvanometer mirror.

  In recent years, in order to achieve higher density, the oscillation wavelength of a semiconductor laser (LD) has been shortened (because the beam spot diameter on the surface to be scanned is proportional to the wavelength of the light source).

  Conventionally, LDs with a wavelength of 780 nm have been widely used, but LDs with a wavelength of 430 nm or less have begun to be used for the above purpose. For example, 405 nm / 780 nm = 0.55, and the diameter can be reduced to about 1/2.

  An LD having a wavelength of 430 nm or less has a different constituent material from an LD having a wavelength of 780 nm, and the constituent material of an LD having a wavelength of 780 nm is generally composed of an AlGaAs system, but an LD having a wavelength of 430 nm or less is composed of a GaN system or the like. For this reason, an LD with a wavelength of 430 nm or less generates a larger amount of heat than an LD with a wavelength of 780 nm, and is likely to cause degradation of droop characteristics. Therefore, in order to reduce the oscillation wavelength of the LD (430 nm or less), it is necessary to reduce the amount of heat generated by the LD.

  In order to reduce the amount of heat generated by the LD, it is only necessary to reduce the oscillation output of the LD. To that end, a multi-beam light source unit combining a plurality of LDs may be configured. In the case of the first embodiment, since the photosensitive drum is scanned with two light fluxes by combining the semiconductor lasers that are two light sources, the output can be half that of one case.

  As a multi-beam light source unit, a light source unit is constituted by a plurality of light sources (LD), and a plurality of light source units are combined to further increase the number of light beams scanned on the photosensitive member.

  Thereby, the output speed of the image forming apparatus can be improved. On the other hand, if the output speed is not changed, the rotation speed of the deflector can be reduced, and a writing optical system considering the environment, such as reduction of power consumption and heat generation, can be configured. It becomes possible.

  In the first embodiment, the semiconductor laser (LD) is used as the light source. However, by using a “semiconductor laser array in which a plurality of light emitting points are monolithically arrayed” (LDA) as the light source, an equivalent effect can be obtained. Can do. A divergent light beam emitted from a plurality of light emitting points may be coupled by a common coupling lens, and a plurality of combinations thereof may be configured as a light source unit. Further, a multi-beam light source unit may be configured using a “surface emitting laser array in which a plurality of light emitting points are two-dimensionally arrayed” as a light source.

  By installing the multi-beam light source unit as described above, a multi-beam optical scanning device can be configured.

FIG. 18 shows an example of an image forming apparatus equipped with the optical scanning device.
Around the photosensitive drum 901, a charging charger 902 that charges the photosensitive member to a high voltage, a developing roller 903 that attaches the charged toner to the electrostatic latent image recorded by the optical scanning device 900, and visualizes it, a developing roller A toner cartridge 904 for replenishing toner and a cleaning case 905 for scraping and storing the toner remaining on the drum are disposed. As described above, a plurality of lines are scanned on the photosensitive drum 901 by scanning for each surface of the polygon mirror, and two lines are recorded simultaneously in the first embodiment shown in FIG.

  The image forming stations are arranged in parallel in the moving direction of the transfer belt 906, and yellow, magenta, cyan, and black toner images are sequentially transferred onto the transfer belt at the same timing, and are superimposed to form a color image. Each image forming station has basically the same configuration except that the toner color is different.

  On the other hand, the recording paper is supplied from the paper supply tray 907 by the paper supply roller 908, and is sent out by the registration roller pair 909 in accordance with the recording start timing in the sub-scanning direction, and the color image is transferred from the transfer belt, and the fixing roller After fixing at 910, the paper is discharged onto a paper discharge tray 911 by a paper discharge roller 912 (claims 7 and 8).

  In the first embodiment, the optical scanning device is integrally configured. However, the optical scanning device may be configured as a separate body corresponding to each color, or the optical scanning device may be configured as two bodies.

  With this configuration, an image is formed at a speed four times that of an image forming apparatus having only one photoconductor, that is, an image forming apparatus that requires four writing operations corresponding to four colors. Can be formed.

  Further, the image forming apparatus of the present invention is connected to an electronic arithmetic device (computer or the like), an image information communication system (facsimile or the like), etc. via a network, so that output from a plurality of devices can be performed with one image forming apparatus. An information processing system can be formed. In addition, if multiple image forming devices are connected to the network, the status of each image forming device (the degree of job congestion, whether the power is on, whether it is broken, etc.) can be known from each output request. It is possible to select and output an image output device that is in the best condition (best suited to the user's wishes) (claim 10).

  As described above, the optical scanning device and the image forming apparatus using the optical scanning device according to the present invention have been described based on the first embodiment, but the specific configuration is not limited to the first embodiment, and Design changes and additions are permitted without departing from the spirit of the invention according to each claim of the scope.

  The optical scanning device and the image forming apparatus using the optical scanning device of the present invention can be applied to a digital copying machine, an optical printer, an optical facsimile, an optical plotter, and the like.

FIG. 3 is a perspective view illustrating an optical scanning device that scans four stations according to the first exemplary embodiment. FIG. 3 is a diagram in which a sheet is disposed between a projection and a housing of an optical element that forms an image of a deflected light beam of Example 1 as a light spot on a surface to be scanned. FIG. 3 is a diagram in which a heat insulating sheet is disposed between a projection and a housing of an optical element that focuses the deflected light beam of Example 1 as a light spot on a surface to be scanned. FIG. 3 is a diagram in which protrusions of an optical element that forms an image of the deflected light beam of Example 1 as a light spot on a surface to be scanned are arranged through a hole formed in a sheet. 6 is a diagram illustrating an arrangement state of protrusions in the optical element of Example 1. FIG. FIG. 3 is a diagram illustrating a sheet through which a position corresponding to a protrusion in the optical element of Example 1 passes. 3 is a perspective view illustrating a configuration of a support housing for an anamorphic lens in the optical scanning device according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating a state in which an anamorphic lens is mounted in the optical scanning device according to the first exemplary embodiment when viewed from the optical axis direction, and a cross-sectional view taken along the line AA. 3 is an enlarged view of the periphery of a stepping motor of a scanning line inclination adjusting mechanism in the optical scanning device of Embodiment 1. FIG. FIG. 3 is a diagram illustrating an example of a synchronization detection sensor in the optical scanning device according to the first embodiment. FIG. 3 is a perspective view illustrating a light source unit in the optical scanning device according to the first embodiment. FIG. 3 is a control block diagram illustrating a writing control circuit in the optical scanning device according to the first exemplary embodiment. FIG. 6 is a signal characteristic diagram in an example in which the phase is delayed by 1/8 clock in the optical scanning device according to the first exemplary embodiment. FIG. 5 is a diagram illustrating an example of setting an interval and a shift amount of pixels for shifting the phase for each divided section of the main scanning region in the optical scanning device according to the first embodiment. FIG. 6 is a diagram illustrating an example of a detection time difference from black as a reference color and a detection time difference of a set of line patterns having different inclination angles in the optical scanning device of the first embodiment. FIG. 6 is a diagram illustrating a change in magnification with respect to temperature in each divided section of the main scanning region in the optical scanning device according to the first embodiment. FIG. 3 is a perspective view illustrating an example of a liquid crystal deflecting optical element that is an optical axis changing unit in the optical scanning device according to the first exemplary embodiment. 1 is a schematic diagram illustrating an example of an image forming apparatus in which an optical scanning device according to Embodiment 1 is mounted. It is the figure which installed in the housing the optical element which focuses the deflection light beam in a prior art example as a light spot on a to-be-scanned surface by a projection part. FIG. 20 is a diagram showing how heat from the housing in the conventional example shown in FIG. 19 is transmitted to the optical element.

Explanation of symbols

101 Photosensitive drum
102 Photosensitive drum
103 Photosensitive drum
104 photoconductor drum
105 Transfer belt
106 polygon mirror
107 Light source unit
108 Light source unit
109 Light source unit
110 Light source unit
111 Incident mirror
112 Incident mirror
113 Cylinder lens
114 cylinder lens
117 Optical axis changing means
118 Optical axis changing means
120 lenses
122 Anamorphic lens
126 Mirror
127 mirror
129 Mirror
130 Mirror
132 Mirror
135 Mirror
138 substrate
139 substrate
152 photodiode
153 photodiode
154 elements
155 Photosensor
156 Condensing lens
B1 beam
B2 beam
B3 beam
B4 beam
201 Optical elements
202 Protrusion
203 housing
204 Sheet (Insulation sheet)
301 Support plate
305 Anamorphic lens
401 pixel clock generator
402 High frequency clock generator
403 counter
404 comparison circuit
405 Light source drive
406 Image processing unit
500 light source unit
501 Semiconductor laser
503,504 coupling lens
505 Base member
507 Holder member
508 groove
512 PCB
513 Cylindrical part
514 Contact surface
900 Optical scanning device
901 Photosensitive drum
902 Charger charger
903 Development roller
904 Toner cartridge
905 Cleaning case
906 Transfer belt
907 Feed tray
908 Feed roller
909 Registration roller pair
910 Fixing roller
911 Output tray
912 Paper discharge roller

Claims (10)

A light source;
A deflector for deflecting the light beam from the light source;
An imaging optical element that forms an image of the deflected light beam as a light spot on the surface to be scanned;
In an optical scanning device comprising a housing containing the above,
The material constituting the housing is made of resin,
At least one imaging optical element among the imaging optical elements is disposed in the casing via a sheet. The optical scanning device according to claim 1,
The optical scanning device, wherein the sheet is a heat insulating sheet. The optical scanning device according to any one of claims 1 to 2,
The imaging optical element is fixed to the housing by a protrusion provided on the imaging optical element,
A sheet is disposed between the surface of the imaging optical element provided with the protrusion and the housing,
The optical scanning device according to claim 1, wherein the thermal conductivity of the sheet is set to have a small difference from the thermal conductivity of the imaging optical element. The optical scanning device according to any one of claims 1 to 2,
The imaging optical element is fixed to the housing by a protrusion provided on the imaging optical element,
A sheet is disposed between the surface of the imaging optical element provided with the protrusion and the housing,
The optical scanning device according to claim 1, wherein the thermal conductivity of the sheet is set to have a small difference from the thermal conductivity of the housing. The optical scanning device according to any one of claims 1 to 4,
Beam spot position deviation detecting means;
Based on the detection result from the beam spot position deviation detection means, the position deviation correction control means for controlling the attitude of the imaging optical element and correcting the beam spot position deviation;
An optical scanning device comprising: The optical scanning device according to any one of claims 1 to 5,
The light source is a multi-beam optical scanning device having a plurality of light emitting points and scanning a surface to be scanned with a plurality of light beams simultaneously. An electrostatic latent image is formed on the image carrier by an optical scanning device, the electrostatic latent image is developed, and the image formed on the image carrier is transferred to a sheet-like recording medium carried on the transfer member. In an image forming apparatus that obtains an image by
An image forming apparatus using an optical scanning device, wherein the optical scanning device according to any one of claims 1 to 6 is used as the optical scanning device. The image forming apparatus using the optical scanning device according to claim 7,
The image forming apparatus is a color image forming apparatus that has a plurality of image carriers, develops an electrostatic image formed on the image carrier with each color toner, and superimposes them on a transfer member to form a color image. An image forming apparatus using an optical scanning device characterized by the above. The image forming apparatus using the optical scanning device according to claim 8.
Color misregistration detection means;
Color misregistration correction control means for controlling the attitude of the imaging optical element based on the detection result from the color misregistration detecting means and performing color misregistration correction;
An image forming apparatus using an optical scanning device. An image forming apparatus using the optical scanning device according to any one of claims 7 to 9,
An image forming apparatus using an optical scanning device, wherein the image forming apparatus has a network communication function.

Images