JP2007249002A - Optical scanner/image forming apparatus/method of adjusting optical scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner which can flexibly accept the assembly error and variation in the configuration thereof and can always provide excellent adjustment accuracy thereby achieving improvement in image quality. <P>SOLUTION: The casing of the optical scanner is composed of two casings: a first casing 14 which holds a light source 1, a coupling lens 2, an aperture 3, a cylindrical lens 4, an optical deflector 5 and a scanning lens 6; and a second casing 15 which holds a bending mirror 7 being a guiding optical element. Optical elements except an optical deflector 5 are adjustable in their position and attitude. An adjustment regarding focusing is first performed solely in the first casing 14, wherein the adjustment amount of the focusing position of the optical elements which the first casing 14 has is so determined to absorb the deviation of the focusing position generated in the adjustment of the scanning position performed in the optical element which the second casing 15 has. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical scanning device that optically scans a surface to be scanned, a copying machine having the optical scanning device, a printer, a facsimile, a multifunction peripheral having at least two of these, an image forming apparatus such as a plotter, and an optical scanning device. The adjustment method and the manufacturing method of the optical scanning device.

Optical scanning devices are widely known in connection with digital copying devices and laser printers.
The quality degradation of the optical scanning device includes mechanical degradation typified by attachment error and shape error, and temperature characteristic degradation with respect to the temperature change of the device.
Regarding mechanical deterioration, a method of absorbing deterioration during assembly, such as mounting while adjusting an optical element, is widely used, and many applications have been filed such as adjustment methods related thereto.
When performing the adjustment, there is a problem of when to perform the adjustment and from which optical element to adjust, and the adjustable range and the expandability of the assembly method vary depending on the setting. Therefore, the adjustment method and the adjustment order are as important as the optical design.

Patent Document 1 discloses a method for adjusting an optical scanning device in which a scanning lens (fθ lens) and a cylindrical lens are positioned with an adhesive applied and fixed by irradiating ultraviolet rays for the purpose of improving the quality of scanning lines. Has been.
In this case, the scanning lens is positioned directly on the base (housing) of the optical scanning device, and the cylindrical lens is positioned independently of the scanning lens on a pedestal fixed on the base.

JP 07-234370 A JP 2000-180797 A JP 2000-199867 A

  In the adjustment method described in Patent Literature 1, since it is bonded and fixed after positioning, an error during assembly can be corrected, but since all optical elements are arranged on one base (housing), Flexibility with respect to changes in the configuration of the optical scanning device is low, and it cannot be said that good adjustment accuracy is always obtained.

  The present invention is capable of flexibly responding to errors in assembly and changes in form, always obtaining good adjustment accuracy, and improving image quality, and an image forming apparatus having the optical scanning device The main object of the present invention is to provide a method for adjusting the optical scanning device.

  In order to achieve the above object, according to the first aspect of the present invention, the pre-deflector optical system for shaping the light beam emitted from the light source and guiding it to the optical deflector, and the light beam deflected by the optical deflector Light having a scanning lens system that guides and forms an image on a surface to be scanned, a light guide element that guides a light beam emitted from the scanning lens system to the surface to be scanned, and a housing that holds these optical elements In the scanning device, the casing includes a first casing that holds the light source, the pre-deflector optical system, the optical deflector, and the scanning lens system, and a second casing that holds at least one light guide element. Each of the optical elements is composed of two separate housings, and the optical elements excluding the optical deflector among the optical elements can be adjusted.

  According to a second aspect of the present invention, in the optical scanning device according to the first aspect, at least one of the optical elements excluding the optical deflector is fixed to the casing by bonding. To do.

  According to a third aspect of the present invention, in the optical scanning device according to the second aspect, at least one of the optical elements excluding the optical deflector has a position and orientation on the main scanning plane that are the same as those of the casing. It is not defined by standards.

  According to a fourth aspect of the present invention, in the optical scanning device according to any one of the first to third aspects, power is provided between the optical deflector and the scanning lens system of the first housing. It has a mechanism for attaching a transmission optical element that does not have.

  According to a fifth aspect of the present invention, in the optical scanning device according to any one of the first to fourth aspects, the scanning lens system has a non-power portion having no power in the main scanning direction. It is characterized by.

  According to a sixth aspect of the present invention, in the optical scanning device according to any one of the first to fifth aspects, the scanning lens system includes a single scanning lens.

  According to the seventh aspect of the present invention, the pre-deflector optical system for shaping the light beam emitted from the light source and guiding it to the optical deflector, and the light beam deflected by the optical deflector on the surface to be scanned for image formation In a method for adjusting an optical scanning device, comprising: a scanning lens system to be guided; a light guide element that guides a light beam emitted from the scanning lens system to the scanned surface; and a housing that holds these optical elements. A casing is a separate body of a first casing that holds the light source, the pre-deflector optical system, the optical deflector, and the scanning lens system, and a second casing that holds at least one light guide element. The optical element excluding the optical deflector among the optical elements can be adjusted, and the adjustment is performed by adjusting the image formation with the first casing alone. The imaging position adjustment amount of the optical element of the second housing has Characterized in that it is determined to absorb the imaging position deviation occurring at scan position adjustment performed by the optical element.

  According to an eighth aspect of the present invention, in the method for adjusting an optical scanning device according to the seventh aspect, at least one of the optical elements excluding the optical deflector is fixed to the casing by bonding. It is characterized by.

  According to a ninth aspect of the present invention, in the method for adjusting an optical scanning device according to the eighth aspect, at least one of the optical elements excluding the optical deflector has a position and a posture on the main scanning plane. It is not defined by the standard of the case.

  According to a tenth aspect of the present invention, in the method for adjusting an optical scanning device according to any one of the seventh to ninth aspects, the first housing is disposed between the optical deflector and the scanning lens system. And a mechanism for attaching a transmission optical element having no power.

  According to an eleventh aspect of the present invention, in the method for adjusting an optical scanning device according to any one of the seventh to tenth aspects, the scanning lens system has a non-power portion having no power in the main scanning direction. It is characterized by.

  According to a twelfth aspect of the present invention, in the method of adjusting an optical scanning device according to any one of the seventh to eleventh aspects, the scanning lens system includes a single scanning lens. To do.

  In the invention described in claim 13, a plurality of image carriers are optically scanned by an optical scanning device to form latent images corresponding to the respective colors, and the latent images are visualized by developing means to form a multicolor image. In the obtained image forming apparatus, the optical scanning device according to any one of claims 1 to 6 is used.

  In the invention described in claim 14, a plurality of image carriers are optically scanned by an optical scanning device to form latent images corresponding to the respective colors, and the latent images are visualized by developing means to form a multicolor image. In the obtained image forming apparatus, an optical scanning device capable of performing the adjustment method according to any one of claims 7 to 12 is used as the optical scanning device.

  According to the present invention, image-related adjustment and scanning position adjustment can be performed with high accuracy, and high image quality can always be realized.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a main part of the optical scanning device according to the present embodiment. A divergent light beam emitted from a light source 1 which is a semiconductor laser is coupled to a subsequent optical system by a coupling lens 2. Here, for the sake of simplicity, the light source is described as having a single light emitting point, but the effect of the present invention can be obtained in the case of a light source having a plurality of light emitting points.
When the light beam that has passed through the coupling lens 2 passes through the opening of the aperture 3, the peripheral portion of the light beam is blocked and shaped, and enters the cylindrical lens 4 that is a line image imaging optical system. The cylindrical lens 4 has a power-less direction in the main scanning direction and a positive power in the sub-scanning direction. The cylindrical lens 4 focuses the incident light beam in the sub-scanning direction and deflects the polygon mirror 5 that is an optical deflector. A line image that is long in the main scanning direction is condensed near the reflecting surface.
The coupling lens 2, the aperture 3, and the cylindrical lens 4 constitute a pre-deflector optical system 30.

The light beam reflected by the deflecting reflection surface is deflected at a constant angular velocity as the polygon mirror 5 rotates at a constant speed, and is transmitted through one scanning lens 6 forming a scanning lens system, and the light beam is guided to the surface to be scanned. The optical path is bent by a bending mirror 7 serving as a light guide element, and the light is condensed as a light spot on the photoconductive photosensitive member 8 which is the substance of the surface to be scanned, and the surface to be scanned is optically scanned. In the present embodiment, the scanning lens system is composed of a single scanning lens, but the effects of the present invention can be obtained in the same manner even when a plurality of scanning lenses are configured.
In the case of the single-lens configuration, the first housing 14 can be downsized, and the “optical scanning apparatus capable of flexible adjustment” of the present invention contributes to downsizing of the scanning lens system.

Prior to the optical scanning of the photoconductor 8, the deflected light beam is reflected by the synchronization mirror 9, and is condensed by the synchronization lens 10 on the synchronization detection unit 11 in the main scanning direction. Based on the output of the synchronization detector 11, the write start timing of optical scanning is determined.
The scanning lens 6 is provided with a non-power portion 13 having no power in the main scanning direction.
When optical scanning is performed to write an image on the surface to be scanned, detection of a synchronization signal is essential to align the writing position in the main scanning direction as described above. At this time, if the non-power portion 13 allows the sync signal detection light beam to pass, the temperature stability of the writing position is increased, and the sync signal detection common to the insertion / removal of the transmissive optical element 12 described later is also performed. It is possible to construct an optical system.

The “spot diameter of the light spot” in this specification is defined by 1 / e ² intensity in the line spread function of the light intensity distribution in the light spot on the surface to be scanned.
The “line spread function” is a light spot light intensity distribution: f (Y, Z) based on coordinates Y, Z in the main scanning direction and the sub-scanning direction with reference to the center coordinates of the light spot formed on the surface to be scanned. Is defined, the line spread function in the Z direction: LSZ is
LSZ (Z) = ∫f (Y, Z) dY (integration is performed for the full width of the light spot in the Y direction), and the line spread function in the Y direction: LSY is
LSY (Y) = ∫f (Y, Z) dZ (Integration is performed for the entire width of the light spot in the Z direction).
These line spread functions: LSZ (Z), LSY (Y) are generally of a Gaussian distribution type, and the spot diameters in the Y direction and Z direction are determined by the line spread functions: LSZ (Z), LSY (Y ) Is given by the width in the Y and Z directions of the region that is 1 / e ² or more of the maximum value.
The spot diameter defined above by the line spread function can be easily measured by scanning the light spot at a constant speed with a slit, receiving the light passing through the slit with a photodetector, and integrating the amount of light received. There are also commercially available devices for performing such measurements.

As shown in FIG. 2, the housing in this embodiment includes a light source 1, a coupling lens 2, an aperture 3, a cylindrical lens 4, an optical deflector 5, and a scanning lens 6, and a light guide. It consists of two housings, a second housing 15 for holding the bending mirror 7 which is an optical element.
At the time of adjustment, the position and posture of the coupling lens 2, the cylindrical lens 4 and the scanning lens 6 on the main scanning plane are adjusted by using only the first housing 14 and measuring the adjustment light beam 16, and the adhesive. Adhere using.

Here, “position on the main scanning plane” refers to a position (including a position on the optical axis) on a plane orthogonal to the rotation axis of the optical deflector 5, and “posture on the main scanning plane” refers to an optical element. Indicates an arrangement angle with respect to a certain direction on the main scanning plane.
“Light guide” refers to the act of controlling the traveling direction of a light beam to guide the light beam to a desired position. It can be realized in a form using a mirror, a prism or the like.
As an example of the adhesive, a resin that is cured by heating or ultraviolet irradiation can be used.
With this two-casing structure, the second casing 15 can select various optical paths, and various types of optical scanning devices can be configured without changing the adjustment range of the optical performance.

Between the optical deflector 5 and the scanning lens 6 of the first housing 14, there is a mechanism for attaching the transmission optical element 12 having no power. Non-power can be realized by adopting a form of a parallel plate or the like in which the light beam is not subjected to condensing and diverging effects.
The parallel plate-shaped transmissive optical element 12 for blocking heat and noise is detachably held by a holding mechanism 17 of the first housing 14. FIG. 3 shows an example of the holding mechanism. As shown in FIG. 3, the holding mechanism 17 is provided with a groove 17 a for inserting the end portion of the transmissive optical element 12 so as to face the holding mechanism 17.
In the present embodiment, the transmission optical element 12 is configured to correspond to both the pre-deflector optical system 30 and the scanning lens 6, but it corresponds only to the scanning lens 6 depending on the incident angle and reflection angle of the light beam. It can also be a size.

In various arrangement conditions, such as the case being small and the optical deflector 5 being very close to the wall surface of the case, the insertion of the transmissive optical element 12 may not necessarily be a measure against heat interruption, but may be counterproductive. In this case, it is better to remove the transmission optical element 12 for the temperature stability of the optical performance.
When the rotational speed of the optical deflector 5 is high and the problem of noise is more conspicuous than heat, the transmissive optical element 12 may be inserted. Thus, insertion / removal of the transmissive optical element 12 can be easily selected depending on the case.
At that time, for example, by adjusting the positions and postures of the coupling lens 2 and the scanning lens 6 on the main scanning plane at the time of the adjustment, the transmission optical element 12 can be made of the same optical element without adding a new optical element. An optical scanning device corresponding to the presence or absence can be configured.

The coupling lens 2, the cylindrical lens 4, and the scanning lens 6 that perform adjustment, that is, the adjustable optical elements excluding the optical deflector 5, have positions and postures on the main scanning plane that are the same as that of the housing (first housing 14). Not specified by positioning standards.
Since these optical elements need to be installed at optically designed reference positions, a position and posture are determined by temporarily using a removable positioning jig (not shown) during adjustment and bonding. By determining the position and posture with the adhesive, it is not necessary to provide a mechanical holding mechanism, and flexible adjustments that are not limited by the layout are possible.
Since there is no standard for determining the position and orientation on the main scanning plane in the casing, and the jig is attached using a jig, either of the gates may be attached when forming the scanning lens 6.

As an example, FIG. 4 shows a schematic diagram of an optical scanning device designed on the assumption that a transmissive optical element 12 is inserted. FIG. 5 shows the light spot diameter in the main scanning direction formed on the surface to be scanned by this optical scanning device. In FIG. 5, “108 mm” and “−108 mm” indicate the range of the scanning region.
Here, consider a case where the transmissive optical element 12 is removed for reasons such as temperature stability. Although the transmission optical element 12 has a refractive action even though it does not have power, it plays a part in the optical performance of the optical scanning device. If it is simply removed, as shown in FIG. 6, the curvature of field rotates with respect to the image plane, and the optical characteristic is deteriorated such that the deviation between the image heights at the beam waist position becomes large.

Therefore, by adjusting the position and orientation of the optical element as shown by the arrows (2a, 2b, 4a, 6a, 6b) in FIG. 4, as shown in FIG. In addition, optical performance comparable to that before removal of the transmissive optical element 12 can be obtained.
The adjustment (change) will be slightly supplemented with reference to FIGS. 4, 8, and 9. As shown in FIG. 4, the adjustment in the present embodiment is performed by adjusting the position (2a) on the optical axis of the coupling lens 2 and the position (2b) in the main scanning direction, the position (4a) on the optical axis of the cylindrical lens 4, and the scanning lens 6. The main scanning direction position (6a) and the posture (6b) on the main scanning plane.
When the transmissive optical element 12 is inserted, the light ray takes a path as shown by a solid line 18a as shown in FIG. It becomes.
By performing the adjustment as described above, as shown in FIG. 9, the reflection point is returned before removal as shown by the broken line 18c, and the optical characteristics on the surface to be scanned are adjusted accordingly according to the adjustment of the scanning lens 6. It is compensated with.

  By performing the adjustment as described above using only the first casing 14, it is possible to perform adjustment that compensates for variations and errors from the light source 1 to the scanning lens 6. Since the range of selection of the second casing 15 is widened, that is, the degree of freedom of the light guide form to the surface to be scanned is increased, the degree of freedom in designing the image forming apparatus is increased.

When the casing is divided into the first casing 14 and the second casing 15 as described above, an optical element mainly responsible for image formation (eg, coupling lens 2, cylindrical lens 4, aperture 3, light) The deflector 5 and the scanning lens 6) are collected in the first housing 14.
The second casing 15 is integrated with light guiding means for guiding a light beam to the scanned surface, and an imaging position on the scanned surface, that is, a scanning line shape error caused by errors of various optical elements ( Example: Bending / tilting).
When deploying the optical scanning device to various optical scanning devices constituting the image forming apparatus, the division of the housing is effective in the sense that the first housing 14 that does not participate in the light guide can be used in common. is there.

In the process of assembling the optical scanning device, the first housing 14 can focus (adjust the image formation), and the second housing 15 can adjust the scanning position. The outline of adjustment will be described.
The first casing 14 is focused by adjusting the position of the coupling lens 2 and the cylindrical lens 4 in the optical axis direction, for example. This adjustment can bring a focusing effect on the light beam reaching the full image height deflected by the optical deflector 5.
The scanning position of the second housing 15 is adjusted by giving a deviation to the optical path length of each image height, for example, by deforming or rotating the mirror 7 of the light guide element.
Since the scanning position adjustment of the second casing 15 cannot be performed unless the image is formed on the surface to be scanned, it is inevitably necessary to adjust the first casing 14 first.

In the first housing 14, a light receiving means is installed at a position corresponding to the surface to be scanned, a physical quantity serving as an index of the focusing degree such as a spot diameter of a light beam condensed thereon is measured, and the measured value is fed back. Make adjustments. Thereafter, the first casing 14 and the second casing 15 are connected / joined, and the scanning line is adjusted by the light guide means of the second casing 15 this time. Due to the adjustment of the scanning position, the state of focusing on the first housing 14 is lost. In this specification, this is referred to as a side-effect image position shift caused by the adjustment of the second housing 15. Here, if the shift of the imaging position that is a side effect is anticipated in advance in the adjustment amount in the first housing 14, the side effect can be reduced even if the scanning position is adjusted in the second housing 15. .
The outline of the adjustment method is the gist of the present invention, and the configuration and the adjustment method of the present invention solve the problems that inevitably arise as the optical scanning device is reduced in size and price.

Based on the above configuration, the actual adjustment of the optical scanning device will be described in detail.
FIG. 10 shows an example when focusing on the first housing 14. Even if the transmission optical element 12 is not mounted at this time, the effect of the present invention can be obtained in the same manner. The light receiving device 19 is a device that can detect a light spot and measure the diameter thereof.
When the light receiving device 19 is installed at a position equivalent to the surface to be scanned, the adjustment light beam 16 emitted from the optical element is condensed on the light receiving surface of the light receiving device 19 by the optical element of the first housing 14.
At this time, it can be determined from the spot diameter measured by the light receiving device 19 whether or not the surface to be scanned is ideally focused, and the focusing can be achieved by the coupling lens 2, the cylindrical lens 4 or the like. .

Next, the scanning position adjustment in the second housing 15 will be described. The second casing 15 uses a bending mirror 7 as an optical element for guiding light. Although only one mirror is depicted in FIG. 2, the effect of the present invention does not change even if a plurality of mirrors are used.
When the scanning position is measured for each image height with the light receiving device 19, the degree of the scanning position can be known as bending of the scanning line, inclination of the scanning line, and registration position deviation.
FIG. 11 shows a mode in which the scanning line bending and the scanning line inclination are adjusted by the light guide optical element 7. The scanning position of the adjustment light beam 16 deflected by the optical deflector 5 bends as a scanning line shape 31 indicated by a solid line due to an error of each optical element, and is detected with an inclination. Here, bending and tilting of the scanning line can be corrected by bending and tilting the light guide optical element 7 as shown by a broken line.

An example of a mechanism for bending and tilting the light guide optical element 7 is shown in FIG. In the drawing, the adjusting mechanism indicated by reference numerals 32a and 32b presses one point of the light guide optical element 7 with a screw to give bending and inclination.
As for this adjusting mechanism, many inventions such as those using a screw and those using a spring have been made conventionally, but it does not affect the effect of the present invention in any system.
FIG. 13 shows an example of a registration position deviation adjustment mode. The registration position deviation refers to a phenomenon in which the position of the scanning line is shifted in the sub-scanning direction over the entire image height. The resist position deviation can be adjusted by rotating the light guide optical element 7 in the direction along the arrow shown in the figure.

The above scanning line bending, scanning line inclination, and registration position deviation adjustment may be performed by a system provided with a mechanism capable of fixing the post-adjustment light guide optical element 7 posture, or in particular, after adjustment without using a fixing mechanism A method of fixing by bonding with a curable resin or the like may be used.
Performing the adjustment as described above with the second housing 15 changes the optical path with respect to the optical system that has been adjusted with the first housing 14, so that the focus is adjusted after the adjustment with the second housing 15. It will inevitably shift.
Therefore, in the present invention, at the time of adjusting the focus in the first housing 14, “predict the focus deviation that occurs in the adjustment in the second housing 15 and perform the focusing in consideration of it” to solve this problem. It can be avoided.
That is, when the focus adjustment is performed in the first casing 14, the adjustment is performed with the focus slightly shifted, and the shift is absorbed when the scanning line is adjusted in the second casing 15. The focus shift caused by the adjustment in the second housing 15 can be easily calculated from the tolerances assigned to the optical elements.

A second embodiment (image forming apparatus) will be described with reference to FIG.
The laser printer 1000 as an image forming apparatus according to the present embodiment has a “photoconductive photosensitive member formed in a cylindrical shape” as a photosensitive image carrier 1110. Around the image carrier 1110, a charging roller 1121, a developing device 1131, a transfer roller 1141, and a cleaning device 1151 are arranged as charging means. A “corona charger” can also be used as the charging means.
An optical scanning device 1171 that performs optical scanning with the laser beam LB is provided, and “exposure by optical writing” is performed between the charging roller 1121 and the developing device 1131.

In FIG. 14, reference numeral 1161 denotes a fixing device, reference numeral 1181 denotes a cassette, reference numeral 1191 denotes a registration roller pair, reference numeral 1201 denotes a feeding roller, reference numeral 1211 denotes a conveyance path, reference numeral 1221 denotes a discharge roller pair, reference numeral 1231 denotes a tray, reference numeral P Indicates transfer paper as a sheet-like recording medium.
When image formation is performed, the image carrier 1110 that is a photoconductive photosensitive member is rotated at a constant speed in the clockwise direction, the surface thereof is uniformly charged by the charging roller 1121, and the optical beam of the laser beam LB of the optical scanning device 1171 is written. An electrostatic latent image is formed upon exposure to the image. The formed electrostatic latent image is a so-called “negative latent image”, and the image portion is exposed.
This electrostatic latent image is reversely developed by the developing device 1131, and a toner image is formed on the image carrier 1110. The cassette 1181 storing the transfer paper P is detachable from the main body of the image forming apparatus 1000. When the cassette 1181 is mounted as shown in the drawing, the uppermost sheet of the stored transfer paper P is fed by the paper feed roller 1201. Then, the transferred transfer paper P is fed by the registration roller pair 1191 at the leading end. The registration roller pair 1191 feeds the transfer paper P to the transfer unit in time with the toner image on the image carrier 1110 moving to the transfer position.

The transferred transfer paper P is superimposed on the toner image at the transfer portion, and the toner image is electrostatically transferred by the action of the transfer roller 1141. The transfer paper P to which the toner image has been transferred is sent to the fixing device 1161, where the toner image is fixed by the fixing device 1161, passes through the conveyance path 1211, and is discharged onto the tray 1231 by the discharge roller pair 1221.
The surface of the image carrier 1110 after the toner image has been transferred is cleaned by a cleaning device 1151 to remove residual toner, paper dust, and the like.
By using the optical scanning device described in the first embodiment as the optical scanning device 1171, extremely good image formation can be performed.

A third embodiment (multicolor image forming apparatus) will be described with reference to FIG.
In the laser color printer as the multicolor image forming apparatus (color image forming apparatus) according to the present embodiment, a photosensitive image carrier is provided along the extended surface of the intermediate transfer belt 21 stretched between the rollers 102a, 102b, and 102c. The drum-shaped photoconductors 20Y (yellow), 20M (magenta), 20C (cyan), and 20K (black) are arranged in parallel.
Around the photoreceptor 20Y, a primary transfer roller (not shown) provided inside a charging means (not shown), a common optical scanning device 105 as an exposure means, a developing means 106Y, and an intermediate transfer belt 21 in order counterclockwise. Further, a cleaning unit (not shown), a static elimination unit (not shown), and the like are arranged. The same applies to the photoconductors 20M, 20C, and 20K.

An electrostatic latent image of each color component image is formed on each photoconductor 20Y, 20M, 20C, 20K by each laser beam L1, L2, L3, L4 based on the image information of each color, and each developing means 106Y, 106M, 106C. , 106K.
The toner images of the respective colors are sequentially superimposed and transferred onto the intermediate transfer belt 21. The superimposed image is collectively transferred by the secondary transfer roller 102d onto a transfer sheet (recording medium) fed from the sheet feeding cassette 111 at a predetermined timing. After the color image transfer, the intermediate transfer belt 21 is cleaned by a cleaning unit (not shown). The transfer paper is sent to the fixing device 114 where the color image is fixed by heat and pressure.
After the fixing, the transfer sheet is conveyed substantially vertically through the apparatus main body and is discharged to the sheet discharge tray 110 on the upper surface of the apparatus.
By using the optical scanning device 105 described in the first embodiment, extremely good image formation can be performed.

Various photosensitive image carriers can be used. For example, a silver salt film can be used as the image carrier. In this case, a latent image is formed by writing by optical scanning, and this latent image can be visualized by processing by a normal silver salt photographic process. Such an image forming apparatus can be implemented as an optical plate making apparatus or an optical drawing apparatus that draws a CT scan image or the like.
As the photosensitive image carrier, it is also possible to use a color developing medium (positive printing paper) that develops color by the thermal energy of the light spot during optical scanning. In this case, a visible image is directly formed by optical scanning. it can.
As the photosensitive image bearing member, a photoconductive photosensitive member can also be used. As the photoconductive photoreceptor, a sheet-like one such as zinc oxide paper can be used, or a selenium photoreceptor, an organic optical semiconductor, or the like that is repeatedly used in the form of a drum or a belt can be used. .

When a photoconductive photoconductor is used as an image carrier, an electrostatic latent image is formed by uniform charging of the photoconductor and optical scanning by an optical scanning device. The electrostatic latent image is visualized as a toner image by development. The toner image is directly fixed on the photoconductor when the photoconductor is in the form of a sheet such as zinc oxide paper, and transfer paper or an OHP sheet when the photoconductor can be used repeatedly. It is transferred and fixed on a sheet-like recording medium such as (plastic sheet for overhead projector).
The transfer of the toner image from the photoconductive photosensitive member to the sheet-like recording medium may be directly transferred from the photosensitive member to the sheet-like recording medium (direct transfer method), or may be temporarily transferred from the photosensitive member to an intermediate transfer belt or the like. After transfer to the intermediate transfer medium, transfer from the intermediate transfer medium to a sheet-like recording medium (intermediate transfer method) may be performed.
Such an image forming apparatus can be implemented as an optical printer, an optical plotter, a digital copying apparatus, or the like.

(About the effect of the present invention on the environment)
According to the present invention, the housing and the optical element for holding the optical scanning device are made common without special processing and installation of a mechanism, and the number of parts associated with the realization of various optical scanning devices is reduced. For this reason, the amount of material used for the production of the optical scanning device can be reduced, and the environmental load related to the amount of mining resources can be reduced.

It is a principal part perspective view of the optical scanning device concerning a 1st embodiment. It is a perspective view which shows the division | segmentation structure of a housing | casing. It is a perspective view which shows the holding mechanism of a transmissive optical element. It is an outline top view showing adjustment of an optical element in the 1st case. It is a figure which shows the light spot diameter before transmission optical element removal. It is a figure which shows the light spot diameter before adjustment after removal of a transmission optical element. It is a figure which shows the light spot diameter after adjustment after transmission optical element removal. It is a figure which shows the position shift of the light ray (light beam) after the transmission optical element removal. It is a figure which shows the state by which the position shift of the light ray (light beam) was corrected by adjustment of an optical element. It is a perspective view showing adjustment operation in the 1st case. It is a perspective view showing adjustment operation in the 2nd case. It is a perspective view which shows an example of the adjustment mechanism of a light guide element. It is a perspective view showing other adjustment operations in the 2nd case. It is a schematic block diagram of the image forming apparatus which concerns on 2nd Embodiment. It is a schematic block diagram of the multicolor image forming apparatus which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor laser as light source 5 Optical deflector 6 Scan lens as scanning lens system 7 Bending mirror as light guide element 8 Photoconductor as scanning surface 12 Transmission optical element 13 Non-power part 14 First housing 15 Second Enclosure

Claims (14)

A pre-deflector optical system for shaping a light beam emitted from a light source and guiding the light beam to an optical deflector; a scanning lens system for guiding the light beam deflected by the optical deflector onto a surface to be scanned; and the scanning lens. In an optical scanning device having a light guide element that guides a light beam emitted from a system to the surface to be scanned, and a housing that holds these optical elements.
The housing includes a first housing that holds the light source, the pre-deflector optical system, the optical deflector, and the scanning lens system, and a second housing that holds at least one light guide element. An optical scanning device comprising two body casings, wherein an optical element excluding the optical deflector among the optical elements is adjustable. The optical scanning device according to claim 1,
An optical scanning device, wherein at least one of the optical elements excluding the optical deflector is fixed to the casing by adhesion. The optical scanning device according to claim 2,
The optical scanning device according to claim 1, wherein at least one of the optical elements excluding the optical deflector is not defined by a reference of the casing for a position and a posture on a main scanning plane. The optical scanning device according to any one of claims 1 to 3,
An optical scanning device comprising a mechanism for attaching a transmission optical element having no power between the optical deflector and the scanning lens system of the first casing. The optical scanning device according to any one of claims 1 to 4,
The scanning lens system has a non-power portion having no power in the main scanning direction. The optical scanning device according to any one of claims 1 to 5,
The scanning lens system is constituted by a single scanning lens. A pre-deflector optical system for shaping a light beam emitted from a light source and guiding the light beam to an optical deflector; a scanning lens system for guiding the light beam deflected by the optical deflector onto a surface to be scanned; and the scanning lens. In an optical scanning device having a light guide element that guides a light beam emitted from a system to the surface to be scanned, and a housing that holds these optical elements.
The housing includes a first housing that holds the light source, the pre-deflector optical system, the optical deflector, and the scanning lens system, and a second housing that holds at least one light guide element. The optical element excluding the optical deflector among the optical elements can be adjusted, and the adjustment is performed by adjusting the image formation with the first casing alone. An image forming position adjustment amount of an optical element included in the body is determined so as to absorb an image forming position shift generated by a scanning position adjustment performed by the optical element included in the second casing. Method for adjusting a scanning device. In the adjustment method of the optical scanning device according to claim 7,
An adjustment method of an optical scanning device, wherein at least one of the optical elements excluding the optical deflector is fixed to the casing by adhesion. In the adjustment method of the optical scanning device according to claim 8,
The method of adjusting an optical scanning device according to claim 1, wherein at least one of the optical elements excluding the optical deflector is not defined by a reference of the housing for a position and an attitude on a main scanning plane. In the adjustment method of the optical scanning device according to any one of claims 7 to 9,
An adjustment method for an optical scanning device, comprising: a mechanism for attaching a transmission optical element having no power between the optical deflector and the scanning lens system of the first housing. In the adjustment method of the optical scanning device according to any one of claims 7 to 10,
The method of adjusting an optical scanning device, wherein the scanning lens system has a non-power portion having no power in the main scanning direction. In the adjustment method of the optical scanning device according to any one of claims 7 to 11,
The method of adjusting an optical scanning device, wherein the scanning lens system is composed of a single scanning lens. In an image forming apparatus that forms a latent image corresponding to each color by performing optical scanning with an optical scanning device on a plurality of image carriers, and visualizes the latent image with a developing unit to obtain a multicolor image.
An image forming apparatus using the optical scanning device according to claim 1. In an image forming apparatus that forms a latent image corresponding to each color by performing optical scanning with an optical scanning device on a plurality of image carriers, and visualizes the latent image with a developing unit to obtain a multicolor image.
An image forming apparatus using an optical scanning apparatus capable of performing the adjustment method according to claim 7 as the optical scanning apparatus.

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