JP2005088445A - Optical scanner and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner and an image forming device that can accurately correct the curving of a scan line and/or uniform velocity in an initial state attributed to the warping of an image forming element included in a scanning image forming optical system and having an adjusting means capable of effectively restraining a deformation due to a temperature change. <P>SOLUTION: The optical scanner has a first image forming system guiding a light flux from a light source unit 21 to a polarization means 23 through an optical element 22 and a second image forming system having an optical element 101 concentrating a light flux polarized by the polarization means 23 on a scanned surface as a light spot and scanning at an equal velocity. The scanner uses a differential screw mechanism having a threaded portion formed in a driving shaft 132 driven by a driving source 131, a threaded portion threadedly engaging with a threaded portion, a nut member 137, on the outside of which a gear portion 137a is formed, and gear rows 134, 135 and 136 transmitting the rotation of a driving shaft to a gear portion 137a for an adjustment means 90 for adjusting at least an inclination of a scan line scanned on a scanned surface by the second image forming system. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a position and orientation adjusting mechanism, and an optical scanning apparatus and an image forming apparatus including the same.

  In a conventional positioning mechanism or position adjusting mechanism, a screw and a nut are attached between an object that needs to be moved or adjusted and a drive source, and the object is moved linearly by driving a motor. What performs position adjustment is known. Although this system has a simple configuration, the minimum moving resolution is a value that is simply determined by the screw pitch / motor rotation resolution, so increasing the resolution causes problems in terms of processing and costs, and achieves a resolution of 1 μm or less. It has become very difficult.

  Conventionally, a spur gear reduction mechanism is known as a method of giving a rotation difference between a motor shaft and a final output shaft. In this method, a large gear and a small gear are integrally formed on the upper and lower stages of a single shaft, and a large reduction ratio is obtained by meshing them in many stages. Usually, meshing of four or more stages is required. In this case, backlash always occurs at one meshing portion, and the backlash accumulates and increases corresponding to the number of meshing portions. Therefore, when a stepping motor is used as the motor, it becomes impossible to obtain the rotation of the final output shaft corresponding to one pulse even if the step angle is made fine. As a countermeasure, an encoder is directly connected to the final output shaft, and the output pulse is counted and the footback control is performed with high accuracy.

  Concerning an optical scanning device, a light beam from a light source is deflected by light deflecting means such as a rotary polygon mirror, and the deflected light beam is condensed toward a scanned surface using a scanning imaging optical system such as an fθ lens. Thus, there is known an optical scanning device that forms a light spot on a surface to be scanned and scans the surface to be scanned with the light spot. Such an optical scanning device is widely known as being mounted on an image forming apparatus such as an optical printer, an optical plotter, or a digital copying machine.

  An image forming apparatus using an optical scanning device includes an image writing step of writing an image by optical scanning as one step in the image forming process. The quality of an image formed by the image process is determined by optical scanning. It is influenced by the quality of 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 of the optical scanning device is the constant speed of optical scanning. For example, when a rotating polygon mirror is used as the light deflecting means, the light beam is deflected at a constant angular velocity. Therefore, in order to realize the constant speed of the optical scanning, a scanning imaging optical system having an fθ characteristic is used. ing. However, it is not easy to realize perfect fθ characteristics due to the relationship with other performance required for the scanning imaging optical system. For this reason, in the actual optical scanning, the optical scanning is not performed at a completely constant 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 in the optical scanning device include scanning line bending and scanning line inclination. A scanning line is a movement locus of a light spot on a surface to be scanned such as a belt-shaped or drum-shaped photoconductor, and is ideally a straight line, and the optical scanning device is designed so that the scanning line is a straight line. It has been broken. However, in practice, the scanning line is generally bent due to processing errors or assembly errors of optical elements or mechanical parts. In principle, when an imaging mirror is used as the scanning imaging optical system and an angle is formed in the sub-scanning direction of the deflected light beam between the incident direction and the reflected direction of the deflected light beam, Even when the scanning line is bent and the scanning imaging optical system is configured as a lens system, the scanning line is bent in the multi-beam scanning method in which the scanning surface is optically scanned with a plurality of light spots separated in the sub-scanning direction. Inevitable.

  The inclination of the scanning line is a phenomenon in which the scanning line is not correctly 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 “bending of the scanning line”.

  If the constant speed of optical scanning is not perfect, distortion in the main scanning direction occurs in the formed image, and scanning line bending causes distortion in the sub-scanning direction in the formed image. When an image is so-called monochrome and is written by a single optical scanning device, it can be formed if scanning line bending or incompleteness of constant velocity (deviation from ideal constant velocity scanning) is suppressed to some extent. The resulting image is not distorted to the extent that it can be seen with the naked eye, but such image distortion is as small as possible.

  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 these color component images are superimposed to form a color image synthetically. Forming is conventionally performed by a color copying machine or the like. As one of the methods for performing such color image formation, an image carrier for each color component is used as an image carrier that can form an image for each color component using an optical scanning device provided for each color component. There is a so-called tandem type image forming system that forms on the body. In the case of such an image forming method, if the scanning line curvature or inclination differs between the optical scanning devices, even if the scanning line bending for each optical scanning device is corrected, An abnormal image called “deviation” appears, which degrades the image quality of the color image.

  Further, as a way of causing the color misregistration phenomenon, there is a phenomenon that the color tone in the color image does not become a desired one. Conventionally, in order to prevent the occurrence of the above-described problems such as color misregistration, the support portion on one side that sandwiches the optical axis of the long lens constituting the imaging optical system in the sub-scanning direction is provided on the long lens. A configuration that uses an adjustment screw that is movable in the optical axis direction, and that corrects scanning line bending by rotating the long lens in a cross section perpendicular to the deflection scanning direction by tightening the adjustment screw is disclosed in Patent Literature 1 is proposed.

JP 2002-131684 A (Claim 1, FIG. 3)

  In the configuration disclosed in Patent Document 1, there is a case where the scanning line bending cannot still be corrected with respect to environmental fluctuations that are affected by the material of the lens used in the imaging optical system to be adjusted. The reason is as follows.

  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 is frequently used because it can be manufactured at a low cost. 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 affect the degree of bending of the scanning line and the constant velocity. For this reason, for example, when several tens of color images are continuously formed, the internal temperature rises due to the continuous operation of the image forming apparatus, and the optical characteristics of the imaging optical system change. The bending and constant speed of the scanning lines written by the device gradually change, and color hues may be greatly different between the color image obtained in the initial stage and the color image obtained in the final stage due to the phenomenon of color misregistration. .

  A scanning imaging lens such as an fθ lens, which is a typical 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. In the case where the scanning imaging lens is composed of a plurality of lenses, the lens length in the main scanning direction increases as the arrangement position moves away from the light deflecting unit, and the length has a length of more than 10 cm to 20 cm. A scale 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 becomes a bow shape in the sub-scanning direction. It becomes. Such warpage of the long lens causes the scanning line bending described above, but when the warping is significant, the scanning line bending also occurs extremely.

  Such a phenomenon occurs even when the initial adjustment is performed using the configuration shown in Patent Document 1. In addition, in the configuration of Patent Document 1, no countermeasure is taken against the inclination of the scanning line that causes problems such as color misregistration other than scanning line bending. Further, the configuration disclosed in Patent Document 1 has a problem in that it is difficult to ensure positioning accuracy because positioning in the optical axis direction changes depending on how the screws are fastened.

  As in the prior art, when an encoder is directly connected to the final output shaft and the output pulses are counted and the footback control is performed with high accuracy, there are problems such as an increase in cost and space.

  An object of the present invention is to solve the problem in the image forming apparatus equipped with the conventional optical scanning device, and to bend the scanning line and / or the like in the initial state due to the warp of the imaging element included in the scanning imaging optical system. An object of the present invention is to provide an optical scanning apparatus and an image forming apparatus provided with an adjusting means that can accurately correct speed and can effectively suppress deformation caused by a temperature change.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a position / posture adjustment apparatus that can perform adjustment on an object to be adjusted with a low cost and a simple configuration in a systematic manner.

  The invention of claim 1 is an adjustment mechanism that adjusts at least the position or posture of an object, and includes a drive source for driving the object and a screw portion formed on a drive shaft that is rotationally driven by the drive source. And a screw member screwed to the screw part, a nut member having a tooth part formed on the outside thereof, and a gear train that transmits the rotation of the drive shaft to the tooth part.

  According to a second aspect of the present invention, in the adjusting mechanism according to the first aspect, the drive source is a stepping motor, and the differential screw mechanism satisfies a relationship of minimum movement of the nut member <(screw pitch / (360 / step angle)). It is characterized by the construction.

  According to a third aspect of the present invention, a light source unit, a first imaging system that guides the light beam from the light source unit to the light deflecting means through the optical element, and the light beam deflected by the light deflecting means as a light spot on the surface to be scanned. In an optical scanning device having a second imaging system having a plurality of optical elements that are condensed and scanned at a constant speed, at least one of the plurality of optical elements is an object to be scanned by the second imaging system The adjusting mechanism according to claim 1 or 2 is used as an adjusting means for adjusting at least an inclination of a scanning line scanned on the surface.

  According to a fourth aspect of the present invention, a light beam from one or more light sources is deflected by a light deflecting means, and a light spot is formed on the surface to be scanned corresponding to the light source by one or more scanning imaging optical systems. In an optical scanning device that performs optical scanning, scanning that corrects the posture in the sub-scanning direction of one or more imaging elements included in the scanning imaging optical system, and the bending, position, and inclination of the scanning line in one or more imaging elements. And a line adjusting mechanism.

  According to a fifth aspect of the present invention, in the optical scanning device according to the fourth aspect, the one or more imaging elements of the scanning imaging optical system are resin imaging elements.

  According to a sixth aspect of the present invention, in the optical scanning device according to the fifth aspect, the scanning line adjusting mechanism includes a shape holding means for holding the resin imaging element from the sub scanning direction, and the resin imaging element in the sub scanning direction. A scanning line bending correction unit that adjusts the scanning line bending by the resin imaging element, and a first driving source that adjusts the scanning line position by the resin imaging element by displacing the shape holding unit. A scanning line position correcting unit; and a scanning line inclination correcting unit having a second drive source that adjusts the inclination of the scanning line by the resin imaging element by displacing the shape holding unit. The line bending correcting means, the scanning line position correcting means, and the scanning line inclination correcting means are configured integrally with the resin imaging element.

  According to a seventh aspect of the present invention, in the optical scanning device according to the sixth aspect, the scanning line bending correction means, the scanning line position correction means, and the scanning line inclination correction means are integrally configured with respect to the shape holding means. It is said.

  The invention according to claim 8 is the optical scanning device according to claim 6 or 7, further comprising a scanning line position detecting device for detecting a position of the scanning line position, and based on detection information from the scanning line position detecting device, The shape holding means is rotated about the optical axis by driving the drive source.

  According to a ninth aspect of the present invention, in the optical scanning device according to the sixth, seventh, or eighth aspect, the optical scanning device includes a posture detecting unit that detects a posture of the shape holding unit, and the second driving is performed based on detection information from the posture control unit. The shape holding means is rotated in the sub-scanning ship direction by driving the source.

  According to a tenth aspect of the present invention, in the optical scanning device according to the sixth, seventh, eighth, or ninth aspect, the shape maintaining means suppresses warpage of the resin imaging element in the sub-scanning direction from the sub-scanning direction over time. This is a feature that suppresses changes in the shape of the material.

  According to an eleventh aspect of the present invention, in the optical scanning device according to the eighth or ninth aspect, the scanning line bending by the resin imaging element is only subjected to initial adjustment by the scanning line bending correction means, and the scanning line position by the resin imaging element and The inclination is corrected by controlling the posture of the resin imaging element by the scanning line position correcting means and / or the scanning line inclination correcting means, and the scanning line position and / or inclination variation with respect to the temporal change including the temperature characteristics is corrected. The first or second drive source of the scanning line position correcting means and / or the scanning line inclination correcting means is driven and controlled based on the detection result of the detecting means for detecting the scanning line position, the color misregistration detecting means or the attitude detecting means. It is characterized by doing.

  According to a twelfth aspect of the present invention, in the optical scanning device according to the seventh or eighth aspect, the shape holding means are disposed opposite to each other in the sub-scanning direction, and a pair of holding members that sandwich the resin imaging element, and the resin A gap holding portion that is substantially the same as or thinner than the thickness of the imaging element in the sub-scanning direction and that is disposed outside the both ends in the longitudinal direction of the resin imaging element that intersects the sub-scanning direction. The pair of holding members are fastened to each other via the interval holding portion, and the scanning line curve adjusting means is longer in the longitudinal direction of the resin imaging element than both ends of the resin imaging element, and the resin imaging element. The resin imaging element is disposed at a distance in the longitudinal direction of the resin imaging element on the reference surface provided on the surface of one opposing holding member and the other holding member positioned on the side facing the reference surface. Pressing means for pressing the child toward the reference plane It is characterized by a door.

  A thirteenth aspect of the present invention is the optical scanning device according to the twelfth aspect of the present invention, wherein the fixed side member on which the shape holding means is mounted is interposed between the fixing member and both ends of the shape holding means, and the shape holding member It has the elastic member which connects a fixing member elastically, It is characterized by the above-mentioned.

  According to a fourteenth aspect of the present invention, in the optical scanning device according to the thirteenth aspect, a reference pin is disposed at a reference position of the fixed side member so as to contact one holding member of the shape holding means, and the shape holding means is provided. It is characterized by being swingably supported with respect to the fixed member.

  According to a fifteenth aspect of the invention, in the optical scanning device according to the ninth aspect of the invention, the scanning line bending correction means is provided on the shape holding member so as to come into contact with the resin imaging element. And a pressing member that is provided on the shape holding member so as to be movable in the longitudinal direction of the resin imaging element, and that presses the sphere or columnar member against the resin imaging element on an inclined surface; And a plurality of scanning line bending correction mechanisms for correcting the scanning line bending by bending the resin optical element in the sub-scanning direction by moving the pressing member in the longitudinal direction of the resin imaging element. It is said.

  A sixteenth aspect of the invention is characterized in that, in the optical scanning device according to the ninth aspect, the adjusting mechanism according to the first aspect is used as a scanning line inclination adjusting means.

  The invention according to claim 17 is the optical scanning device according to claim 9, wherein the adjustment mechanism according to claim 2 is used as the scanning line inclination adjusting means.

  According to an eighteenth aspect of the present invention, in the optical scanning device according to any one of the fourteenth to seventeenth aspects, the position of the reference pin relative to the one holding member or the resin imaging element is in the main scanning direction and the sub scanning direction. The scanning line position adjusting means is positioned on the extension of the optical axis, and the scanning line tilt adjusting means is substantially aligned with the resin in the direction orthogonal to the optical axis. It is characterized by being arranged on an axial extension of the optical center of the image element.

  According to a nineteenth aspect of the present invention, an image carrier and an image forming apparatus that obtains a desired recorded image by visualizing a latent image formed on the image carrier by optical scanning by the optical scanning device is used as the optical scanning device. The optical scanning device according to any one of Items 18 to 18 is used.

  According to a twentieth aspect of the present invention, in the image forming apparatus according to the nineteenth aspect, a plurality of image carriers are provided.

  According to the present invention, since the differential screw mechanism can be operated with a simple component such as a combination of gears, a low-cost adjustment mechanism for an object can be provided. Further, since the minimum resolution can be made sufficiently smaller than the resolution by the conventional screw and nut method, it is possible to achieve more accurate position / posture adjustment accuracy. Further, according to the differential screw system of the present invention, the number of meshing portions is small, the backlash can be minimized as compared with the conventional system, and the encoder is not required, so that the adjustment mechanism is small and low cost.

  According to the present invention, the scanning line bending, the scanning line position, and the scanning line inclination can be adjusted by the scanning line adjustment mechanism, so that the environmental variation such as the initial adjustment of the scanning line bending inclination and the increase in the machine temperature due to the accumulation of mechanical errors. Color shift can be reduced because feedback control can be performed even with respect to the secular change.

  According to the present invention, in a state in which the shape holding means and the resin imaging element are integrated, and the scanning line bending of the resin imaging element is corrected by the scanning line adjustment mechanism provided integrally with the shape holding means. Since the scanning line position and / or the scanning line inclination can be controlled collectively, the structure is simple and the adjustment points can be concentrated on one resin imaging element, so that the parts cost and assembly cost The cost can be reduced.

  According to the present invention, the scanning line position and the scanning line inclination can be corrected independently and with higher accuracy than in the past by using a differential screw mechanism with a simple structure and by placing the fulcrum position substantially at the center. In addition, it is possible to maintain excellent vibration resistance.

  According to the present invention, the scanning line can be individually bent and the scanning line position and / or inclination can be corrected with respect to the image carrier serving as a plurality of scanned surfaces, so that the scanning state is prevented from being different for each scanning surface. It becomes possible.

  According to the present invention, when used as an optical scanning device of a tandem-type multicolor image forming apparatus using an electrophotographic process, the scanning line bends, the scanning line position and / or the scanning line on the image carrier to be scanned. Since the line inclination can be corrected and corrected, it is possible to increase the density of monochromatic and multicolor output images, increase the speed by multibeam, and improve the image quality with little color shift. Furthermore, it leads to a reduction in power consumption, vibration noise, and heat generation, thereby reducing the environmental load.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Before describing the configuration of an optical scanning device according to an embodiment of the present invention, an image forming apparatus to which the optical scanning device is applied will be described with reference to FIG. The image forming apparatus denoted by reference numeral 1 in FIG. 11 is a copier capable of forming a full color image (multicolor image). Other examples of the image forming apparatus include a facsimile apparatus capable of performing the same image forming process as the above-described copying machine and printer based on a received image signal, and a complex machine thereof. The image forming apparatus includes not only a color image but also an apparatus that targets a single color image.

  The image forming apparatus 1 includes a photosensitive drum 1A serving as a plurality of image carriers that can be separated into four colors of yellow, cyan, magenta, and black and can form an image corresponding to each color and serve as a scanned surface. The image forming apparatus 1 that uses a tandem structure in which 2A, 3A, and 4A are arranged in parallel in the horizontal direction can move a visible image formed on each photosensitive drum while facing each photosensitive drum. The recording medium is configured to be superimposed and transferred onto a transfer sheet S that is a recording medium conveyed by the transfer belt 5.

The configuration related to the image forming process will be described as a representative of one photosensitive drum 1A as follows. Since the other photosensitive drums 2A to 4A have the same configuration and processing, the parts related to the photosensitive drums 2A to 4A are denoted by the reference numerals assigned to the members related to the photosensitive drum 1A for convenience. A detailed description is omitted here.
Around the photosensitive drum 1A, a charging device 1B using a configuration such as corotron or scotron to perform image forming processing along the rotation direction indicated by an arrow, and an optical scanning device 20 using laser light from a laser light source. A developing device 1D and a cleaning device 1E are arranged.

  In the image forming apparatus 1, the document reading unit 6 is disposed above the image forming unit in which these apparatuses for performing image forming processing are disposed, and reads a document (not shown) placed on the document placing table 6 </ b> A. Image information read by the apparatus 7 is output to an image processing control unit (not shown), and writing information for the optical scanning apparatus 20 described above can be obtained. In FIG. 11, a corona discharge method using a discharge wire, which employs a contact method using a roller, can be used for the charging device 1 </ b> B. In this embodiment, the developing devices 1D to 4D are arranged in the order in which yellow, cyan, magenta, and black toners can be supplied from the right side of the extended portion of the transfer belt 5 in FIG.

  The reading device 7 forms an image of a light source 7A for scanning an unillustrated document placed on the document placement table 6A and a reflected light from the document on a CCD 7B provided corresponding to each color separation. A plurality of reflecting mirrors 7C and an imaging lens 7D are provided, and image information corresponding to the light intensity for each color separation is output from each CCD 7B to an image processing control unit (not shown).

  The transfer belt 5 is composed of a member made of a dielectric material such as a polyester film wound around a plurality of rollers, and one of the stretched portions faces the photosensitive drums 1A to 4A, and faces each photosensitive drum. Transfer devices 8A, 8B, 8C, and 8D are arranged inside the positions, respectively. The transfer devices 8 </ b> A to 8 </ b> D are configured to electrostatically attract the images carried on the photosensitive drums 1 </ b> A to 4 </ b> A toward the paper S using positive corona discharge. To the transfer belt 5, a sheet S as a recording medium fed from the sheet feeding cassette 10 </ b> A of the sheet feeding device 10 is fed via the registration roller 9, and the sheet S is transferred to the transfer belt 5. It is electrostatically attracted and conveyed by corona discharge from 8A. In FIG. 11, reference numeral 13 denotes a cleaning device that removes the toner remaining on the transfer belt 5.

  A separation device 11 that separates the sheet S from the transfer belt 5 is located at a position where the sheet S on which image transfer from the photoconductive drums 1A to 4A has been completed, and a belt is sandwiched between the other portions of the stretched portion. Opposing static eliminating devices 12 are respectively disposed.

  The separator 11 performs negative AC corona discharge from the upper surface of the paper S to neutralize the charge accumulated on the paper S and release the electrostatic adsorption state, thereby reducing the curvature of the transfer belt 5. Separation using the toner is enabled, and toner dust is prevented from being generated due to peeling discharge during separation. The static eliminator 12 neutralizes the accumulated charge of the transfer belt 5 by performing negative AC corona discharge having a polarity opposite to the charging characteristics of the transfer devices 8A to 8D from both the front and back surfaces of the transfer belt 5 to perform electrical initialization. Is supposed to do.

  In the photosensitive drums 1 </ b> A to 4 </ b> A, the surfaces of the photosensitive drums 1 </ b> A to 4 </ b> A are uniformly charged by the charging devices 1 </ b> B to 4 </ b> B, and writing is performed based on image information for each color separation color read by the reading device 7 in the document reading unit 6. An electrostatic latent image is formed on the photosensitive drum using the devices 1C to 4C, and the electrostatic latent image is visible by toner of a color having a complementary color relationship corresponding to the color separation color supplied from the developing devices 1D to 4D. After image processing, electrostatic transfer is performed via the transfer devices 8 </ b> A to 8 </ b> D to the paper S carried by the transfer belt 5 and conveyed. The sheet S to which the image for each color separation carried on each of the photosensitive drums 1A to 4A is transferred is discharged by the charge removing device 11 and then is separated by using the curvature of the transfer belt 5, and then the fixing device 14 is used. The toner in the unfixed image is fixed and discharged.

  In such a quadruple tandem image forming apparatus, it is difficult to increase the cost by simply increasing the component accuracy and assembly accuracy in order to obtain a resist so that there is no color misregistration of the four colors. In the present invention, self-printing is performed in the apparatus, and the amount of color misregistration in the sub-scanning direction is recognized from the self-printing. Is realized. In practice, a patch pattern for recognizing color misregistration is created on the transfer belt 5, and this is detected by a P sensor as color misregistration detection means (not shown). After forming a line-shaped four-color pattern and recognizing how much the other Y, M, and C colors have shifted in the forward or backward direction with reference to the black line as a reference, color misregistration correction is performed for writing each color. carry out. The detection and correction are performed when the entire process control is performed when the power is turned on to start the image forming apparatus, when the temperature difference in the apparatus reaches 5 ° C., when several hundreds of jobs are in progress, and each photosensitive drum and each development. For example, when the unit including the apparatus unit and the transfer belt 5 is replaced. When the correction process is completed, these patterns are cleaned by a cleaning bias roller (not shown) and removed from the transfer belt 5.

  Next, the optical scanning device 20 for the above-described plurality of photosensitive drums will be described. FIG. 1 is a diagram showing a basic configuration of an optical device. In FIG. 1, an optical scanning device 20 includes a light source unit 21 using two semiconductor lasers 21A and 21B as light sources, a cylindrical lens 22 as an optical element, a polygon mirror 23 as an optical deflecting means, a scanning optical element and a coupling element. The second imaging system 24B using the fθ lens is provided. In the optical scanning device 20, the two light beams 210A and 210B, which are light beams emitted from the light source unit 21, are applied to the deflecting and reflecting surface of the polygon mirror 23 by the action of the cylindrical lens 22 constituting the first imaging system 24A. After being imaged as a line image (imaged in the sub-scanning direction and long in the main-scanning direction), the second imaging system 24 used the light spot on the surface to be scanned (photosensitive drum: indicated by reference numeral 1A for convenience). It is configured to scan. In FIG. 1, the light source unit 21 includes a semiconductor laser and a coupling lens, but is not limited to such a configuration. When the optical scanning device 20 is used as an optical writing device of an image output device, the light beam is modulated corresponding to the output image data, but the electrical signal (synchronization signal) for the modulation start timing is In this case, the light is incident on the synchronization detection plate 25.

  As shown in FIG. 2, the light beams 210 </ b> A and 210 </ b> B have a configuration (main scanning section) that intersects at an angle θ in the vicinity of the deflection reflection surface of the polygon mirror 23. As a result, it is possible to suppress the occurrence of deviation in optical characteristics (field curvature, magnification error, etc.) between the two beams. As shown in FIG. 3, the two spot lights BS1 and BS2 on the surface to be scanned corresponding to the photosensitive drum (for convenience, reference numeral 1A) are predetermined in the sub-scanning direction according to the scanning density. It is required to maintain the interval PZ (beam pitch). In order to make this interval PZ predetermined, an angle φ formed between the light beam 210A and the light beam 210B may be set as shown in FIG.

  The scanning line is inclined and bent due to the accuracy of the optical element alone, mainly the bending of the bus line, and the accumulation of arrangement errors when assembled to the optical housing. For this reason, in this embodiment, means for detecting the scanning line bend and inclination on the surface to be scanned 1A (photosensitive drum) is provided in the optical scanning device 20, or the color shift of the color patch formed on the transfer belt 5 is described above. The position of the fθ lens (also referred to as a long lens) that becomes a resin imaging element by driving a stepping motor, which will be described later, is detected by the P sensor and based on the detection result, and γ tilt as will be described later. By doing so, the scanning line inclination is corrected. In the scanning line bending correction, initial scanning line bending adjustment is performed in a state where all the optical elements are assembled, and thereafter, readjustment or feedback control for scanning line bending correction is not performed when the image forming apparatus is in operation.

Here, the bending amount (size) of the scanning line will be described. This is due to the amount generated in the optical scanning device itself and factors other than the optical scanning device such as the inclination due to the tilt of the photosensitive drum axis. The accumulated bending inclination is generated as the bending inclination of the image, and an inclination of up to several hundred microns may occur. In this embodiment, the optical scanning device 20 aims to correct factors other than those generated by the optical scanning device 20.
In this embodiment, it is possible to achieve an accuracy of several tens of microns or less by adjusting the inclination of several hundreds of microns by a scanning line adjustment mechanism 90 described later and further performing feedback control for color shift including temperature fluctuation. It becomes.

  FIG. 5 shows one form of the scanning position detecting means. 5A and 5B show the case where the scanning line detecting means is arranged inside or in the vicinity of the optical scanning device, and in FIG. 5A, the scanning position detecting means indicated by symbol AS is arranged outside the effective image area. In addition, a detection reflection mirror M is arranged on the optical path of the imaging light beam to detect a scanning position shift. In FIG. 5B, a half mirror indicated by reference numeral HM is provided on the optical path of the imaging light beam. The scanning position detecting means AS detects it. By using the half mirror HM, it is possible to detect the scanning line position at a multipoint image height.

  5C and 5D irradiates from the light source P a color shift (transfer position shift between the color images) of the toner image T on the photosensitive drum 1A and the toner image T on the transfer belt 5. This is a method in which the light reflection state is detected by the scanning position detecting means (area sensor) AS through the lens L, and the scanning position detecting means 180 is constituted by the light source P, the lens L, and the area sensor AS. The scanning position detection unit 180 having such a configuration may increase the accuracy because detection is performed in a process close to the final image.

  The optical scanning device 20 having the above configuration is provided with a scanning line adjustment mechanism 90 as shown in FIG. The scanning line adjustment mechanism 90 includes a scanning line bending correction unit 100, a scanning line position correction unit 120, and a scanning line inclination correction unit 130. A part of the members constituting the scanning line bending correction unit 100 and a part of the members constituting the scanning line inclination correction unit 130 and the scanning line position correction unit 120 are integrated with the shape holding unit 105 as described later. Is provided.

Hereinafter, this configuration will be described in detail.
The scanning line adjustment mechanism 90 shown in FIG. 6 shows an example in which the long lens 101 serving as a resin imaging element used in the second imaging system 24 is integrated with the shape holding means 105. The scanning line bending in this embodiment is eliminated by correcting and holding the warp of the long lens 101 in the sub-scanning direction by the scanning line bending correction unit 100, and the inclination of the scanning line is substantially the same as that of the long lens 101. An inclination about the optical axis (indicated by reference numeral γ in FIG. 6) is corrected by the scanning line inclination correcting means 130 and held. Note that the scanning line adjustment mechanism 90 is also provided separately for the second scanning lens 101A shown in FIG. 10, and a part of the members constituting them has the same configuration as the shape holding means 105. It is integrally provided with the shape holding means 105A.

  The shape holding means 105 supports the long lens 101 from the sub-scanning direction B, and holds the long lens 101 from the sub-scanning direction B between the holding member 102 and the lower holding member 102 that is long in the main scanning direction A. And an upper holding member 104 to be sandwiched. Each of the holding members 102 and 104 is a sheet metal whose cross section is bent into a U-shape and the bending strength is improved, and is disposed opposite to each other in the sub-scanning direction B. Legs 106 and 106 are formed at both ends 104a and 104b of the holding member 104 as gap holding parts for forming a gap with the holding member 102 and for mounting the holding member 102 thereon. The leg portions 106 and 106 are disposed outside the both end portions 101 a and 101 b of the long lens 101.

  Between the holding member 102 and the long lens 101, a pair of protrusions 103, 103 for forming a reference surface is disposed. The protrusions 103 and 103 are formed or disposed on the long lens 101 by the scanning line bending correction unit 100 so as to correspond to portions other than the pressing position, in other words, non-pressing portions. In the present embodiment, the protrusions 103 and 103 are protruded from the holding member 102 that is a sheet metal by drawing so that the upper surfaces thereof are flush with each other, and have a height of 200 μm. The protrusions 103 and 103 constitute a part of the scanning line bending correction unit 100 in the main scanning direction A and are disposed between the plurality of scanning line bending correction mechanisms 110. For this reason, the long lens 101 has its surface in the sub-scanning direction B abutted against the inner surface of the holding member 104 and the upper surface of the protruding portion 103, and the holding member 102 and the holding member 104 are screwed through the leg portions 106 and 106. By being integrated at 301, it is sandwiched from the sub-scanning direction. By holding the long lens 101 between the holding members 102 and 104 in this way, warpage of the long lens 101 in the sub-scanning direction is suppressed, and a change in shape at the time measurement can be suppressed. At the center of the holding member 102, pins 123 and 124 are formed to sandwich the protrusion 101 c formed at the center of the long lens 101 from the main scanning direction A. The long lens 101 is positioned in the main scanning direction A by inserting the protrusion 101 c between the pins 123 and 124.

  In the scanning line bending correction means 100, the members constituting this are integrated with the holding member 104. The scanning line bending correction unit 100 includes a scanning line bending correction mechanism 110 as a pressing unit that is disposed in the main scanning direction A at intervals. Each scanning line bending correction mechanism 110 includes a pressing member 107, a pressing member 108 for pressing each pressing member 107 against the long lens 101, and a pressing member 108 fixed to the upper surface of the holding member 104 by spot welding or the like. And a bracket 109 having a U-shape for supporting each.

  Each pressing member 107 is a columnar member, and from the other side of the holding member 104 located on the side opposite to the reference surface, that is, from the opposite side of the surface contacting the holding member 102 located below the long lens 101. The long lens 101 is configured to be pressed toward the reference plane. A spherical body may be used for each pressing member 107. As shown in FIG. 7, guide holes 111 and taps 112 larger than the guide holes 111 are opened in the standing bent portions 109 a and 109 b on both sides of the bracket 109. Each pressing member 108 is a taper pin having a small-diameter portion 108b and a large-diameter portion 108c, and a tapered portion 108a constituting an inclined surface connecting the small-diameter portion 108b and the large-diameter portion 108c. A thread is formed on the outer periphery of the large-diameter portion 108c, and a tool groove is formed at the end thereof. That is, each pressing member 108 is configured as a bending adjustment screw.

  Each pressing member 108 is a screw in which the small diameter portion 108b is inserted into the guide hole 111 and the large diameter portion 108c is inserted into the tap 112, and meshes with the tap 7112, and is substantially the same as the main scanning direction A that forms the axial direction thereof. The bracket 109 is movably supported in the same direction, and is thereby integrated with the holding member 104 via the bracket 109. Accordingly, in the scanning line bending correction unit 100, a pressing member 108 that forms a part of this, that is, a part of the scanning line bending correction mechanism 110, is integrated with the holding member 104, that is, the shape holding unit 105, respectively.

  Each pressing member 107 is a roller having a cylindrical shape, and is arranged such that its axial direction is parallel to the optical axis direction C of the long lens 101. Each bracket 109 is formed with a notch 109 a so as to match the shape of each pressing member 107, and the holding member 104 is formed with a hole 110. Each pressing member 107 is dropped into the notch 109 a and the hole 110, and directly contacts the long lens 101. Each pressing member 107 does not directly contact the long lens 101 but may contact through the contact plate or the like.

  Each pressing member 108 has a taper portion 108a in contact with the pressing member 107, and a tool such as a screwdriver is inserted into the tool groove of the pressing member 108 and rotated, and the axial direction thereof, that is, the axial direction of the pressing member 107 By moving in a substantially perpendicular direction (sub-scanning direction B), the pressing position to each pressing member 107 changes, and the position of the long lens 101 with respect to the holding member 104 changes at the position where the pressing member 107 abuts. . Therefore, by rotating the pressing member 108 in each scanning line bending correction mechanism 110, the scanning line bending correction unit 100 scans the scanning line on the photosensitive drum of the beam transmitted through the long lens 101 as a whole. Can be corrected.

  The scanning line bending on the photosensitive drum is caused by the flatness of the long lens 101, the folding mirror M1, the cylinder lens 22, the polygon mirror PM, the first scanning lens L1, the folding mirrors 28A and 28B shown in FIG. This occurs due to the accumulation of warpage of the long lens 101 and the folding mirror 33. By bending only the long lens 101 in the sub-scanning direction as described above by the scanning line bending correction means 110, the bending of the scanning line is eliminated. Is done.

  For example, if the long lens 101 is warped upward, the pressing member 107 provided in the scanning line bending correction mechanism 110 at the center is pushed downward to press the long lens 101 and correct it. If it is warped downward, the pressing member 107 provided in the scanning line bending correction mechanism 110 at both ends may be pushed downward to press the long lens 101 and correct it. The actual scanning line bending amount is a level of several tens of μm, and can be corrected in a region where the holding member 102 and the holding member 104 are not deformed.

  In the long lens 101, sink marks as sink portions occur on the surface with which the pressing member 107 abuts during the molding process. This sink has a certain width in the optical axis direction C along the thick portion. The length of the pressing member 107 in the axial direction, that is, the optical axis direction C is longer than the sink width as is apparent from FIG. 67, and the contact between the pressing member 107 and the long lens 101 is stabilized. To do. Further, since the axial direction of the pressing member 107 is substantially parallel to the optical axis of the long lens 101, the pressing member 107 rotates or slides even when the environmental temperature changes and the long lens 101 expands or contracts. Therefore, the expansion of the long lens 101 in the main scanning direction A and the expansion of the contraction are not hindered, and the change in the optical characteristics can be suppressed. If the aim is to match the amount and direction of warpage between stations of the tandem optical system, the scanning line bending correction means 100 is adjusted by deforming the long lens 101 together with the holding member 102 and the holding member 104. This makes it possible to improve the ease of adjustment.

  As shown in FIG. 6, the scanning line inclination correcting unit 130 is provided integrally with the holding member 104 and is driven so as to incline the shape holding unit 105. The stepping motor 131 is a motor as a second drive source. It has. The stepping motor 131 detects the inclination direction of the shape holding member 105 detected by the posture detection means 160 and 161 for detecting the inclination of the shape holding member 105 and the amount of inclination by a scanning line inclination detection means (not shown) that detects the inclination of the scanning line. Accordingly, the operation is controlled by a computer as control means (not shown).

  In FIG. 6, reference numeral 140 denotes a long lens holder as a fixed side member for mounting the shape holding means 105 integrated with a housing (not shown) of the optical scanning device 20. The fixed side member may be the housing of the optical scanning device 20 itself. As shown in FIG. 7, the long lens holder 140 is provided with a reference pin 142 that protrudes toward the holding member 102. The reference pin 142 has a hemispherical tip that contacts the holding member 102 and constitutes a fulcrum shaft when the shape holding means 105 moves. The reference pin 142 is disposed at the reference position of the long lens holder 140. The reference position substantially coincides with the optical axis, and is arranged so as to be substantially in line with the center of the thickness of the long lens 101 in the optical axis direction and the axis of the stepping motor 128 used for the scanning line position correcting means 120 described later. ing. That is, the position of the reference pin 142 with respect to the holding member 102 or the long lens 101 is substantially coaxial with the center of the long lens 101 in the main scanning direction A and the sub-scanning direction B. For this reason, the long lens holder 140 supports the long shape holding means 105 so that it can be displaced in a direction in which the inclination of the scanning line can be corrected with respect to the long lens holder 140, specifically, swingable.

  When the long lens holder 140 supports the shape holding unit 105 only through the fulcrum shaft 142, the shape holding unit 105 becomes unstable. Therefore, as shown in FIG. The plate spring 122 as an elastic member integrally formed with the other end 102b of the lens and the other end of the long lens holder 140, and the one end 104a of the holding member 104 and one end of the long lens holder 140 are integrally configured. And a leaf spring 121 as an elastic member. The shape holding means 105 is supported by the long lens holder 140 so as to be swingable in a direction in which the inclination of the scanning line can be corrected, and the shape holding means 105 is held in shape with the long lens holder 140 by the elastic force of the leaf spring 121 and the leaf spring 122. By being elastically connected to the means 105, the long lens holder 140 is supported in a stable state by being pressed by the fulcrum shaft 142. That is, the leaf spring 121 and the leaf spring 122 act as torsion beams and can be pressed against the reference pin 142 with spring properties in two directions of β tilt and γ tilt, so that the long shape holding means 105 can be supported without play. It is said. The leaf spring 122 is integrated with the holding member 102 and the long lens holder 140 by a screw 303, and the leaf spring 121 is integrated with the holding member 104 and the long lens holder 140 by a screw 302.

  As shown in FIGS. 3 and 9, the stepping motor 131 is integrated with the other end 104 b of the holding member 104 by a screw 305. In this embodiment, the stepping motor 131 is arranged on the shape holding means 105 on the movable side. However, the stepping motor 131 may be attached on the long lens holder 140 side on the fixed side, or the housing of the optical scanning device 20. It is good also as a structure attached to.

  As shown in FIG. 9, the stepping motor 131 has a stepping motor shaft 132 serving as a drive shaft. A male screw is cut at the tip 132a of the stepping motor shaft 132, and a first gear 134 is fixed to a portion near the holding member 104 so as to be substantially parallel to the holding member 104. The stepping motor shaft 132 is disposed on the axial extension of the optical center of the long lens 101 in a direction orthogonal to the optical axis. An opening 102 c is formed in the holding member 102 located on the extension of the stepping motor shaft 132. A female screw hole 137a is formed in the opening 102c, and a tip 137ba of a nut member 137 attached to the stepping motor shaft 132 is inserted therein. The tip 137 b has a hemispherical shape and is abutted against the long lens holder 140. On the outer periphery of the center of the nut member 137, a tooth portion 137c having the same diameter and the same center as the first gear 134 is formed. A support shaft 138 that is substantially parallel to the stepping motor shaft 132 is attached to the holding member 102 and the holding member 104 in the vicinity of the stepping motor 131. The support shaft 138 is provided with two-stage gears 135 and 136 that mesh with the first gear 134 and the tooth portion 137c of the nut member 137, respectively.

  A differential screw mechanism is configured by the gear train including the stepping motor 131, the nut member 137, and the gears 134, 135, and 136. The posture detection means 160 and 161 are sensors such as photo interrupters, and are arranged at intervals in the main scanning direction A. The posture detection means 160 and 161 detect the vertical movement of the rising portion 104 c of the holding member 104. In this embodiment, the position where the rising portion 104c blocks both sensors is set as the home position, the direction of inclination of the shape holding means 105 is detected with reference to the home position, and the stepping motor is detected by the control means in accordance with the detection. Sequence control for driving 131 is performed.

  Here, the principle of the differential screw mechanism will be described. When the stepping motor 131 is driven to rotate the stepping motor shaft 132, it is transmitted to the tooth portion 137c via the rotating gears 135 and 136. For this reason, the rotation direction of the gear 134 and the tooth portion 137a of the nut member 137 is the same direction. If the number of teeth of the gears 135 and 136 is the same, the number of rotations is the same. Therefore, in this embodiment, a rotational phase difference is generated between the stepping motor shaft 131 and the tooth portion 137c of the nut member 137 by arbitrarily setting the gear ratio of each gear. Since the nut member 137 is displaced in the axial direction by this rotational phase difference, the distance between the shape holding means 105 and the long lens holder 140 changes.

  The minimum resolution of the axial displacement of the nut member 137 is represented by (step angle × rotation phase difference × screw pitch) / 360 × 360. Here, in order to reduce the minimum resolution, the step angle, the male screw and the female screw pitch can be reduced. However, since there is a limit due to the problem of processing cost, the rotational phase difference with a relatively high design freedom is designed to be small. By doing so, a sufficiently small minimum resolution can be obtained as compared with the conventional screw and nut system.

  Further, since the stepping motor 131 detects the inclination direction of the shape holding means 105 by the posture detection means 160 and 161 and is controlled to rotate according to the detection signal, the entire shape holding means 105 is illustrated with the reference pin 142 as a fulcrum. 6 is rotated (γ tilt) in the γ direction shown in FIG. In this embodiment, the stepping motor 131 is disposed on the movable holding member 104, but it may be attached to the fixed side such as the long lens holder 140.

  As shown in FIGS. 6 and 8, the scanning line position correcting unit 120 includes a stepping motor 128 serving as a first drive source and a nut holder 126 that engages with a rotation drive shaft 128 a of the stepping motor. The flange 129 of the stepping motor 128 is fixed to a pedestal 141 provided at the center of the long lens holder 140 by a plurality of screws 303 and 303. The pedestal part 141 is formed at the front end edge of the central part of the long lens holder 140 in the main scanning direction A, that is, at the edge part of the scanning light emission side on one side in the optical axis direction.

  A lead screw is formed on the rotary drive shaft 128a. The rotation drive shaft 128a is disposed on an extension of the optical axis. The nut holder 126 has a cylindrical shape, and has a female screw hole threadedly engaged with the rotary drive shaft 128a formed in the center thereof in the sub scanning direction B, and a flange portion 126a formed at one end. . The nut holder 126 is attached to a protruding piece 102 d provided at the center of the holding member 102. The protruding piece 102d is formed at the front end edge of the central portion of the holding member 102 in the main scanning direction A direction, that is, at the edge of the scanning light emission side on one side in the optical axis direction. A hole for inserting the nut holder 126 is formed at the tip of the protruding piece 102d, and the nut holder 126 is inserted. The flange portion 126a is formed to have a diameter larger than that of the insertion hole, and functions as a member for retaining the nut holder 126 in one direction. In this state, the nut holder 126 is disengaged from the protruding piece 102d upward in FIG. 8, so that a groove is formed on the outer periphery of the nut member 126 positioned below the protruding piece 102d. By inserting the retaining ring 127 into the groove, the projecting piece 102d is sandwiched and held by the flange portion 126a of the nut member 126.

  According to the scanning line position correcting unit 120 having such a configuration, when the stepping motor 128 is driven, the drive shaft 128a rotates, and the nut holder 126 moves in the sub-scanning direction B according to the rotation direction. By this movement, the shape holding means 105 as a whole rotates in the β direction shown in FIG. 6 (β tilt) with the reference pin 142 as a fulcrum, and the inclination of the long lens 101 in the direction orthogonal to the optical axis can be adjusted. The position of the scanning line can be corrected.

  The scanning line position correcting unit 120 of the present embodiment is configured with conventional screws and nuts, but is particularly applicable when high resolution is not required, and is applied to the scanning line inclination correcting unit 130 if necessary. A differential screw method may be used.

  The scanning line adjustment mechanism 90 having the above-described configuration is applied to the optical scanning device 20 including the tandem optical system shown in FIG. 1, and the configuration for that is shown in FIG. In FIG. 10, an optical scanning device 20 comprising a tandem optical system is shown in FIG. 1 for a plurality of photosensitive drums (for the sake of convenience, using the symbols 1A and 1B shown in FIG. 1) capable of forming an image for each color. The basic configuration shown is applied, and the integral bending and / or inclination correction holding means 90 is applied to the long lens (indicated by reference numerals 101 and 101A for convenience) in the configuration. In FIG. 10, reference numerals 27A and 27B indicate first and second scanning semiconductor lasers that form a light source, reference numerals 28A and 28A indicate first scanning folding mirrors, and reference numerals 29A and 29B indicate second scanning. The optical members disposed in the subsequent optical paths with respect to the photosensitive drums 1A and 2A are intended for each photosensitive drum as a second imaging system indicated by reference numeral 24 in FIG. It is composed.

  By using the optical scanning device composed of the tandem optical system having such a configuration, it is possible to suppress the change in shape due to the change in the environmental temperature in the long lenses 101 and 101A, and to suppress the bending of the scanning line due to the change in shape. In this case, the amount of inclination or bending is reduced by the scanning line adjustment mechanism 90, and further, the light spot position can be optimized by detecting the color shift and performing feedback control.

  In this embodiment, the scanning line position adjusting mechanism 90 having a differential screw mechanism appropriately controls the position and orientation of the lens of the optical scanning device for the object to be adjusted. Therefore, the object whose position and orientation are controlled is not limited to the lens, but can be used for general purposes, and may be applied to other than the optical scanning device 20 as a matter of course.

It is a schematic diagram for demonstrating the basic composition of the optical scanning device which concerns on embodiment of this invention. It is a schematic diagram for demonstrating one of the effect | actions of the optical scanning device shown in FIG. It is a schematic diagram for demonstrating another effect | action of the optical scanning device shown in FIG. It is a schematic diagram for demonstrating another example of an effect | action of the optical scanning device shown in FIG. It is a figure for demonstrating the example of the structure for the position shift and color shift detection which are used for the optical scanning device shown in FIG. It is a perspective view which shows the whole structure of the scanning line adjustment mechanism used for the optical scanning device shown in FIG. It is an expanded sectional view which shows the structure of a scanning line curve correction | amendment means. It is an expanded sectional view which shows the structure of a scanning line position correction | amendment means. It is an expanded sectional view which shows the structure of the differential screw mechanism in a scanning line inclination correction means. It is a perspective view for demonstrating the structure of the optical system which provided the scanning line position adjustment means in the optical scanning device of this form for several scanning surfaces. 1 is a schematic diagram illustrating an embodiment of an image forming apparatus to which an optical scanning device of the present invention is applied.

Explanation of symbols

1 Image forming apparatus 1A, 2A, 3A, 4A Image carrier (scanned surface)
21 Light source unit 22, 22A, 22B Optical element 23, PM1, PM2 Light deflecting means 24A First imaging system 24B Second scanning system 20 Optical scanning device 90 Scanning line adjusting means 100 Scanning line bending correcting means 101, 101A Object ( Multiple optical elements)
101a, 101b Both ends 102, 104 of the resin imaging element 102, 104 A pair of holding members 103, 103 Reference planes 104a, 102b Both ends of the shape holding means 105 Shape holding means 106, 106 Spacing holding section 107 ... Cylindrical member 108 ...・ Pressing member 108a ・ ・ Inclined surface 110 ・ ・ Pressing means (scanning line bending correction mechanism)
120 Scanning line position correcting means 121, 122 Elastic member 128, 131 Drive source 128a, 132 Drive shaft 130 Scanning line inclination correcting means 132a Screw part 134, 135, 136 Gear train 137a Screwed screw part 137c Tooth part 137 Nut member 140 Fixed Side member 142 Reference pin 160, 161 Posture detection means A Main scanning direction B Sub scanning direction AS, 180 Scanning line position detection device

Claims (20)

An adjustment mechanism for adjusting at least the position or posture of an object,
A drive source for driving an object; a screw portion formed on a drive shaft that is rotationally driven by the drive source; a screw portion that is screwed to the screw portion; and a nut member that has a tooth portion formed on the outside thereof; And a gear train for transmitting rotation of the drive shaft to the tooth portion. The adjustment mechanism according to claim 1,
The adjustment mechanism characterized in that the drive source is a stepping motor and is constituted by a differential screw mechanism that satisfies a relationship of minimum movement of the nut member <(screw pitch / (360 / step angle)). A light source unit, a first imaging system for guiding a light beam from the light source unit to a light deflecting unit through an optical element, and a light beam deflected by the light deflecting unit as a light spot on the surface to be scanned and at a constant speed In an optical scanning device having a second imaging system comprising a plurality of optical elements to be scanned in
3. The adjustment according to claim 1, wherein at least one of the plurality of optical elements is an object, and adjustment means for adjusting at least an inclination of a scanning line scanned on the scanning surface by the second imaging system. An optical scanning device using a mechanism. Light that performs light scanning by deflecting light beams from one or more light sources by a light deflecting unit and forming a light spot on a surface to be scanned corresponding to the light sources by one or more scanning imaging optical systems. In the scanning device,
A scanning line adjustment mechanism that corrects the attitude in the sub-scanning direction of one or more imaging elements included in the scanning imaging optical system, and the bending, position, and inclination of the scanning lines in one or more of the imaging elements; Optical scanning device. The optical scanning device according to claim 4.
One or more image forming elements of the scanning image forming optical system are resin image forming elements. The optical scanning device according to claim 5.
The scanning line adjustment mechanism includes a shape holding unit that holds the resin imaging element from the sub-scanning direction, and a displacement of the scanning line by the resin imaging element by displacing the resin imaging element in the sub-scanning direction. A scanning line bending correcting means for adjusting the scanning line position, a scanning line position correcting means having a first drive source for adjusting the scanning line position by the resin imaging element by displacing the shape holding means, and the shape holding means And a scanning line inclination correcting means provided with a second drive source for adjusting the inclination of the scanning line by the resin imaging element by displacing
An optical scanning device characterized in that the shape holding means, the scanning line bending correction means, the scanning line position correction means, and the scanning line inclination correction means are integrally formed with the resin imaging element. The optical scanning device according to claim 6.
An optical scanning apparatus characterized in that the scanning line bending correction unit, the scanning line position correction unit, and the scanning line inclination correction unit are configured integrally with the shape holding unit. The optical scanning device according to claim 6 or 7,
A scanning line position detecting device for detecting the position of the scanning line position
An optical scanning device characterized in that, based on detection information from the scanning line position detection device, the first drive source is driven to rotate the shape holding means about an optical axis. The optical scanning device according to claim 6, 7 or 8,
Having an attitude detection means for detecting an attitude of the shape holding means;
An optical scanning device characterized in that, based on detection information from the attitude control means, the second drive source is driven to rotate the shape holding means in the sub-scanning ship direction. The optical scanning device according to claim 6, 7, 8, or 9,
The optical scanning device according to claim 1, wherein the shape holding means suppresses a change in shape over time by suppressing warping of the resin imaging element in the sub-scanning direction from the sub-scanning direction. The optical scanning device according to claim 8 or 9,
The scanning line bending by the resin imaging element is only initially adjusted by the scanning line bending correction means, and the scanning line position and inclination correction by the resin imaging element is performed by the scanning line position correction means and / or the The scanning line inclination correction means controls and corrects the posture of the resin imaging element, and the scanning line position and / or inclination variation with respect to the temporal change including the temperature characteristics is detected by the scanning line position. Light that drives and controls the first or second driving source of the scanning line position correcting unit and / or the scanning line inclination correcting unit based on the detection result of the color misregistration detecting unit or the posture detecting unit. Scanning device. The optical scanning device according to claim 7 or 8,
The shape holding means is arranged to face each other in the sub-scanning direction, and has a pair of holding members that sandwich the resinous imaging element, and a thickness that is substantially the same as or thinner than the thickness of the resinous imaging element. An interval holding portion disposed outside both ends in the longitudinal direction of the resin imaging element that intersects the sub-scanning direction, and the pair of holding members are connected to each other via the interval holding portion. Conclude,
The scanning line bending adjustment means is a reference provided on the surface of one holding member facing the resin imaging element in the longitudinal direction of the resin imaging element from both ends of the resin imaging element. And a pressing member that presses the resin imaging element toward the reference plane, spaced from each other in the longitudinal direction of the resin imaging element on the other holding member located on the side facing the reference plane. An optical scanning device. The optical scanning device according to claim 12, wherein
A fixed-side member for mounting the shape-holding means, and an elastic member that is interposed between the fixing member and both ends of the shape-holding means, and elastically connects the shape-holding member and the fixing member. An optical scanning device comprising: The optical scanning device according to claim 13.
A reference pin is disposed at a reference position of the fixed side member so as to contact one holding member of the shape holding means, and the shape holding means is supported swingably with respect to the fixed member. An optical scanning device. 15. The optical scanning device according to claim 9, wherein
The scanning line bending correction means includes a sphere or a columnar member provided on the shape holding member so as to come into contact with the resin imaging element, and is movable in the longitudinal direction of the resin imaging element. A pressing member that is provided on the shape holding member and presses the spherical or cylindrical member against the resin imaging element on an inclined surface, and moves the pressing member in the longitudinal direction of the resin imaging element. Thus, an optical scanning device comprising a plurality of scanning line bending correction mechanisms for correcting the scanning line bending by bending the resin optical element in the sub-scanning direction. The optical scanning device according to any one of claims 6 to 15,
An optical scanning apparatus using the adjusting mechanism according to claim 1 as the scanning line inclination adjusting means. The optical scanning device according to any one of claims 6 to 15,
An optical scanning apparatus using the adjustment mechanism according to claim 2 as the scanning line inclination adjusting means. The optical scanning device according to any one of claims 14 to 17,
The position of the reference pin with respect to one holding member or the resin imaging element is substantially coaxial with the center of the resin imaging element in the main scanning direction and the sub-scanning direction, and the scanning line position adjusting means is An optical scanning device, which is located on the extension of the optical axis, and wherein the scanning line inclination adjusting means is arranged on the axial extension of the optical center of the resin imaging element in a direction orthogonal to the optical axis. . An image carrier and an image forming apparatus that visualizes a latent image formed on the image carrier by optical scanning by an optical scanning device and obtains a desired recorded image.
An image forming apparatus using the optical scanning device according to claim 3 as the optical scanning device. The image forming apparatus according to claim 19.
An image forming apparatus comprising a plurality of the image carriers.

Images