JP4298091B2 - Method for assembling scanning optical device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionMethod for assembling scanning optical deviceIn particular, the height (position of the scanning line in the sub-scanning direction) or / and the inclination of the scanning line on the surface to be scanned (image carrier surface) is adjusted by a folding mirror disposed between the deflecting means and the surface to be scanned. For example, it is suitable for an apparatus such as a laser beam printer or a digital copying machine having an electrophotographic process.
[0002]
[Prior art]
Conventionally, in a scanning optical device used in a laser beam printer (LBP), a digital copying machine or the like, a light beam which is light-modulated from a light source means according to an image signal is emitted from a rotating polygon mirror (polygon mirror) by an optical deflector. The light is periodically deflected and focused on a surface of a photosensitive recording medium (photosensitive drum) by scanning optical means (imaging element) having fθ characteristics, and the surface is optically scanned to perform image recording. Yes.
[0003]
FIG. 10 is a schematic view of the main part of this type of conventional scanning optical apparatus.
[0004]
In the figure, a divergent light beam emitted from a semiconductor laser 91 as a light source means is made into a substantially parallel light beam by a collimator lens 92, and the light beam (light quantity) is limited by a stop 94 and has a predetermined refractive power only in the sub-scanning direction. It is incident on a cylindrical lens 93. Out of the substantially parallel light beam incident on the cylindrical 93, it exits in the state of the substantially parallel light beam as it is in the main scanning section. In the sub-scan section, the light beam is converged and formed as a substantially linear image on a deflection surface (reflection surface) 95a of an optical deflector 95 comprising a rotating polygon mirror (polygon mirror).
[0005]
Then, the light beam deflected and reflected by the deflecting surface 95a of the optical deflector 95 is guided by a scanning optical means 96 having fθ characteristics through a folding mirror 98 onto a photosensitive drum surface 97 as a scanned surface, and the optical deflector. By rotating 95 in the direction of arrow A, the photosensitive drum surface 97 is optically scanned in the direction of arrow B (main scanning direction). As a result, an image is recorded on the photosensitive drum surface 97 as a recording medium.
[0006]
In the figure, a folding mirror 98 is disposed behind the scanning optical means 96, and the optical path of the light beam from the scanning optical means 96 is bent toward the photosensitive drum surface 97, thereby reducing the size of the entire apparatus.
[0007]
In this specification, the main scanning direction is a direction parallel to the deflection scanning direction, and the sub-scanning direction is a direction perpendicular to the deflection scanning direction, and so on.
[0008]
[Problems to be solved by the invention]
In this type of scanning optical apparatus, there is a case where the scanning optical means is composed of a plurality of optical elements and a folding mirror is disposed in the optical path between the plurality of optical elements due to the necessity of the configuration. In such a case, if there is an assembly error of the folding mirror when the luminous flux is incident on the optical element on the downstream side of the folding mirror (on the photosensitive drum side when the arrangement position of the folding mirror is used as a reference), the luminous flux is optical. The light is incident on a position off the optical axis of the element. As a result, there is a problem that the height of the scanning line on the surface to be scanned is shifted from a desired position, or the scanning line is inclined. Further, when the light beam is incident off the optical axis of the optical element, the imaging spot on the surface to be scanned is rotated, and there is an effect that a good image cannot be obtained.
[0009]
Furthermore, even if the folding mirror is assembled at a desired position, the folding mirror may be affected by the accuracy of individual optical components and assembly errors upstream of the folding mirror (on the semiconductor laser side with respect to the position of the folding mirror). When the light beam is incident on the optical element on the downstream side of the mirror, the light beam is incident on a position off the optical axis of the optical element, and the height of the scanning line on the surface to be scanned is desired as described above. Detrimental effects such as deviation from the position and inclination of the scanning line occur.
[0010]
Usually, the assembly error of the folding mirror and the single product accuracy and assembly error of the optical components upstream of the folding mirror can occur at the same time, which further promotes the scanning line height error and the tilt error.
[0011]
In recent years, various color image forming apparatuses that form an image using a plurality of scanning optical devices have been proposed in particular for color copying machines, color laser beam printers, and the like, because of the demand for higher speed of the apparatus.
[0012]
However, for example, when a plurality of scanning optical devices in which the inclination of the scanning line is generated as described above, if the inclination direction and the inclination amount are the same, the scanning lines are matched and a good image is obtained. However, since a tilt error or the like usually randomly occurs, the scanning lines do not coincide with each other, causing a color shift in the image.
[0013]
For example, when a plurality of scanning optical devices in which the above-described scanning line height error is generated are used, writing of each scanning optical device is performed in accordance with the randomly generated scanning line height error. By adjusting the timing, it is possible to match the scanning lines at the time of image formation, but the incident angle of the light flux with respect to the photosensitive drum surface (image carrier surface) varies depending on the height error of the scanning lines.
[0014]
In the case of a multi-beam scanning optical apparatus using a multi-beam light source that generates a plurality of light beams in response to a demand for further speeding up, as the incident angle of the light beams on the photosensitive drum surface increases as shown in FIG. The scanning widths L1 and L2 written on the drum surface are different from each other.
[0015]
In addition, as shown in FIG. 12, when the incident angle of the light beam on the photosensitive drum surface is θ, the incident angle θ becomes large if the distance (lateral deviation) between the extended line of the light beam and the central portion of the photosensitive drum surface is d. As a result, the lateral displacement d increases.
[0016]
FIG. 13 is a numerical example showing the amount of change in scanning width difference depending on the incident angle between two beams at a resolution of 600 dpi. The horizontal axis represents the amount of lateral deviation d, and the vertical axis represents the amount of jitter (Jitter) with the difference in scanning width on one side. It is said. As shown in the figure, it can be seen that the amount of jitter increases in proportion to the amount of lateral deviation. That is, jitter in the main scanning direction occurs due to the difference in scanning width between the two beams, which adversely affects the image. For this reason, the incident angle with respect to the photosensitive drum surface also varies due to variations in the height error of the scanning line of each scanning optical device, and as a result, the jitter in the main scanning direction varies, causing a color shift in the image.
[0017]
  According to the present invention, a detection unit detects a height error or / and an inclination error of a scanning line on a surface to be scanned (image carrier surface) caused by single component accuracy and assembly error of an optical component in a scanning optical device, and the detection is performed. By adjusting the position of the folding mirror disposed between the deflecting means and the surface to be scanned by the adjusting means based on the received signal, the height error or / and the tilt error of the scanning line can be suppressed, and a high-definition image can be obtained. ObtainableMethod for assembling scanning optical deviceThe purpose is to provide.
[0018]
[Means for Solving the Problems]
  The method of assembling the scanning optical apparatus according to the first aspect of the invention comprises a light source means, a deflection means for deflecting and scanning a light beam emitted from the light source means, and a light beam deflected and scanned by a deflection surface of the deflection means. A method of assembling a scanning optical apparatus comprising: a plurality of imaging optical elements that form an image on a surface; and a mirror that is disposed in an optical path between the plurality of imaging optical elements.
  The imaging optical element disposed in the optical path between the deflection surface and the mirror is disposed in the optical path, and the imaging optical element disposed in the optical path between the mirror and the scanned surface is the optical path. In the state where the adjusting optical element is not disposed in the optical path between the mirror and the scanned surface, and the detecting means is disposed at a position where the light beam that has passed through the adjusting optical element is imaged. An error in the height of the scanning line on the surface to be scanned is detected by the detection means, and the mirror is rotated based on an axis parallel to the longitudinal direction of the mirror based on the signal detected by the detection means. By rotating, the height of the scanning line on the scanned surface is adjusted,Then, between the mirror and the scanned surfaceIn the light pathThe image forming optical element arranged in is attached to the scanning optical device.
[0019]
  According to a second aspect of the present invention, there is provided a scanning optical device assembling method comprising: a light source means; a deflection means for deflecting and scanning a light beam emitted from the light source means; and a light beam deflected and scanned by a deflection surface of the deflection means. A method of assembling a scanning optical apparatus comprising: a plurality of imaging optical elements that form an image on a surface; and a mirror that is disposed in an optical path between the plurality of imaging optical elements.
  The imaging optical element disposed in the optical path between the deflection surface and the mirror is disposed in the optical path, and the imaging optical element disposed in the optical path between the mirror and the scanned surface is the optical path. In the state where the adjusting optical element is not disposed in the optical path between the mirror and the scanned surface, and the detecting means is disposed at a position where the light beam that has passed through the adjusting optical element is imaged. An error in the inclination of the scanning line on the surface to be scanned is detected by the detecting means, and the mirror is set based on a signal detected by the detecting means with an axis parallel to the short direction of the mirror as a rotation axis. By rotating, the inclination of the scanning line on the scanned surface is adjusted,Thereafter, an imaging optical element disposed in an optical path between the mirror and the surface to be scanned is attached to the scanning optical device.
  The invention of claim 3 is the invention of claim 1 or 2, whereinThe light source unit emits a plurality of light beams, and a plurality of scanning lines are simultaneously formed on the surface to be scanned by the plurality of light beams emitted from the light source unit.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
1 is a perspective view of a main part of Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view (sub-scanning cross-sectional view) of the main part in the sub-scanning direction of Embodiment 1 of the present invention.
[0031]
In the figure, reference numeral 1 denotes a light source means, for example, a semiconductor laser. A collimator lens 2 converts a divergent light beam (light beam) emitted from the light source means 1 into a substantially parallel light beam. Reference numeral 4 denotes an aperture stop, which limits a passing light beam (light quantity). The aperture of the aperture stop 4 has an elliptical shape, the beam width is restricted in both the main scanning direction and the sub-scanning direction, and the spot shape on the scanned surface 7 (image holding surface) becomes a desired size. As described above, the size of the opening is set. A cylindrical lens (cylinder lens) 3 has a predetermined power only in the sub-scanning direction, and the light beam that has passed through the aperture stop 4 is substantially applied to a deflecting surface 5a of an optical deflector 5 to be described later in the sub-scanning section. It is formed as a line image.
[0032]
Each element such as the light source means 1, the collimator lens 2, the aperture stop 4, and the cylindrical lens 3 constitutes one element of the incident optical means 11.
[0033]
Reference numeral 5 denotes an optical deflector composed of, for example, a polygon mirror (rotating polygonal mirror) as a deflecting means, and is rotated at a constant speed in the direction of arrow A in the figure by a driving means (not shown) such as a motor.
[0034]
  Reference numeral 6 denotes scanning optical means having fθ characteristics, and first and second scanning lenses (fθ lenses) having a predetermined power.(Imaging optical element)6a and 6b, and has a tilt correction function by providing a conjugate relationship between the deflecting surface 5a of the optical deflector 5 and the scanned surface 7 in the sub-scanning section.
[0035]
Reference numeral 8 denotes a folding mirror, which is disposed in the optical path between the first scanning lens 6a and the second scanning lens 6b, and bends the incident light beam toward the scanned surface 7 side. In the present embodiment, the height of the scanning line (the position of the scanning line in the sub-scanning direction) or / and the inclination on the surface to be scanned 7 are adjusted based on a signal obtained by the detection means described later using the folding mirror 8. Adjustment is made by means.
[0036]
Reference numeral 7 denotes a photosensitive drum surface (image carrier surface) as a surface to be scanned.
[0037]
In this embodiment, the divergent light beam emitted from the semiconductor laser 1 is converted into a substantially parallel light beam by the collimator lens 2, and the light beam (light amount) is limited by the aperture stop 4 and is incident on the cylindrical lens 3. Of the substantially parallel light beam incident on the cylindrical lens 3, it is emitted as it is in the main scanning section. In the sub-scan section, the light beam converges and forms a substantially linear image (a linear image long in the main scanning direction) on the deflecting surface 5a of the optical deflector 5. The light beam reflected and deflected by the deflecting surface 5a of the optical deflector 5 is spot-formed on the surface of the photosensitive drum 7 through the first scanning lens 6a, the folding mirror 8, and the second scanning lens 6b. By rotating the optical deflector 5 in the direction of arrow A, the surface of the photosensitive drum 7 is optically scanned in the direction of arrow B (main scanning direction) at a constant speed.
[0038]
Next, a method for adjusting the height or / and inclination of the scanning line on the surface to be scanned according to the present embodiment will be described with reference to FIGS. FIG. 3 is a sub-scan sectional view of the main part at the time of adjustment of the present embodiment, and FIG. 4 is a schematic view of the main part of the optical system at the time of adjustment of the present embodiment. In FIG. 3 and FIG. 4, the same elements as those shown in FIG. 1 and FIG.
[0039]
In the figure, reference numeral 41 denotes a detection means, which has a pair of detection units (41a, 41b). The detection units (41a, 41b) are arranged on both sides of the scanning center on the scanning surface 7 on both sides ( The height error or / and the inclination error of the scanning line on the scanned surface 7 is detected at each point (two image heights) of the maximum vertical field angle.
[0040]
The detection unit (41a, 41b) is a detection provided at or near the focus position of the adjustment optical element (9a, 9b) and the adjustment optical element (9a, 9b) substantially corresponding to the second scanning lens 6b. It has an element (sensor) (10a, 10b).
[0041]
In the present embodiment, the height error or / and the inclination error of the scanning line on the scanning surface is detected by the detecting means 41, and the scanning line height or the scanning line on the scanning surface 7 is detected based on the detected signal. / And the inclination is adjusted by using the folding mirror 8, and then the second scanning lens 6b is assembled to the apparatus main body on the downstream side of the folding mirror 8 (on the photosensitive drum side with respect to the arrangement position of the folding mirror). .
[0042]
An adjusting means (not shown) is attached to the folding mirror 8 so as to be rotatable about an axis parallel to the longitudinal direction and the short direction of the folding mirror 8. As shown in FIG. 5, the adjusting means can adjust the height of the scanning line by rotating the folding mirror 8 about the axis 8a parallel to the longitudinal direction as a rotation axis. Further, as shown in FIG. 6, the adjusting means can adjust the inclination of the scanning line by rotating the folding mirror 8 about the axis 8b parallel to the short direction as the rotation axis.
[0043]
In this embodiment, each detection unit (41a, 41b) is disposed only during adjustment, and the sensor (10a) is formed such that the light beam is imaged on the sensor (10a, 10b) surface by the adjustment optical elements (9a, 9b). , 10b), the height or / and the inclination of the scanning line on the surface to be scanned 7 is adjusted by adjusting the attitude of the folding mirror 8 by the adjusting means based on the signals from.
[0044]
In the present embodiment, as described above, the adjustment optical elements (9a, 9b) substantially corresponding to the second scanning lens 6b correspond to the respective points on both sides of the scanning center in the scanning range on the scanned surface 7. By providing, the sensitivity in the scanning line adjustment of the folding mirror 8 can be brought close to the actual optical system. Further, by arranging the sensors (10a, 10b) at or near the focus position by the adjusting optical elements (9a, 9b) as described above, the height of the scanning line on the scanned surface 7 by the two sensors 10a, 10b is increased. A depth error or / and a tilt error can be detected.
[0045]
In the present embodiment, as described above, the scanning line is adjusted before the second scanning lens 6b is assembled to the apparatus main body, and the procedure for assembling the second scanning lens 6b is performed after the adjustment. Therefore, in the present embodiment, the height error and the tilt error of the scanning line caused by the single-piece accuracy and the assembly error due to the optical components on the folding mirror 8 and its upstream side (semiconductor laser side when the arrangement position of the folding mirror is used as a reference) are adjusted. As a result, the height error and the tilt error of the scanning line that is finally left are only those that are generated due to the single product accuracy and the assembly error caused by the optical components downstream of the folding mirror 8.
[0046]
Thus, in the present embodiment, as described above, the detection means 41 detects the height error or / and the tilt error of the scanning line on the surface to be scanned 7 due to the single-component accuracy and assembly error of the optical components in the scanning optical apparatus. The height error or / and the tilt error of the scanning line can be suppressed by adjusting the posture of the folding mirror 8 provided in the scanning optical means 6 based on the detected signal by the adjusting means. High-definition images are obtained.
[0047]
In this embodiment, a pair of detection units are provided as detection means. However, more detection units may be provided. In this embodiment, the folding mirror is provided between the first and second scanning lenses. However, the present invention can be applied in the same manner as in the first embodiment even if the folding mirror is provided before and after the first and second scanning lenses. can do. For example, when provided on the downstream side of the first and second scanning lenses, detection elements are provided at a plurality of positions in the main scanning direction on the surface to be scanned, and the folding mirror is based on the signals detected by the detection elements. The height or / and inclination of the scanning line on the surface to be scanned may be adjusted by adjusting the posture of the scanning line. In this embodiment, the scanning optical device using a semiconductor laser that emits a single light beam (single beam) has been described. However, the present invention is not limited to this. For example, a multi-beam semiconductor laser that emits a plurality of light beams (multi-beam) is used. Even in the used multi-beam scanning optical apparatus, the present invention can obtain the same effects as those of the first embodiment.
[0048]
[Color image forming apparatus]
FIG. 7 uses four scanning optical devices adjusted in this way at the same time, records image information for each color on different photosensitive drum surfaces (image carrier surfaces), and forms a color image. 1 is a schematic view of a main part of a tandem type color image forming apparatus used in a color laser beam printer or the like.
[0049]
In the figure, 11, 12, 13, and 14 are scanning optical devices, 21, 22, 23, and 24 are photosensitive drums as image carriers, and 31 is a conveyor belt.
[0050]
As described above, the color image forming apparatus according to the present embodiment uses the light beams based on the respective modulation signals by the four scanning optical devices 11, 12, 13 and 14, and the corresponding photosensitive drums 21, 22, 23, It is formed on the 24th surface. For example, latent images of C (cyan), M (magenta), Y (yellow), and B (black) are formed on the corresponding photosensitive drums 21, 22, 23, and 24, and then multiple-transferred onto a recording material. One full color image is formed.
[0051]
In the figure, the tilt error of the four relative scanning lines is caused by only the accuracy of the single product and the assembly error caused by the optical components on the downstream side of the folding mirrors 8 (8a to 8d). Therefore, a good color image can be formed. The same applies to the scanning line height error, and since the incident angle error with respect to the photosensitive drum surface caused by the scanning line height error is small, for example, the main scanning direction between the beams when using multiple beams. The jitter at is sufficiently within the allowable amount.
[0052]
As described above, in this embodiment, the scanning optical device is used for a color image forming apparatus, for example, by adjusting the height or / and the inclination of the scanning line on the scanned surface 7 using the folding mirror 8 as described above. A good image with little color misregistration can be obtained.
[0053]
[Reference example 1]
  FIG. 8 illustrates the present invention.Reference example 1It is principal part sectional drawing (sub-scanning sectional view) of the sub-scanning direction at the time of adjustment. In the figure, the same elements as those shown in FIG.
[0054]
  BookReference exampleThe difference from the first embodiment is that the height or / and the inclination of the scanning line on the scanned surface 7 is adjusted by the folding mirror 8 after all the optical elements constituting the apparatus are assembled to the apparatus main body. And two sensors 10a and 10b as detection means 41 are provided at or near the position of the second scanning lens 6b on the downstream side of the folding mirror 8, and the surface to be scanned is provided by the two sensors 10a and 10b. 7 that the height error or / and the tilt error of the scanning line on 7 has been detected..
[0055]
  That is, bookReference exampleThen, the sensor 10 (10a, 10b) for detecting the light beam position is disposed only at the time of adjustment at the position of the second scanning lens 6b on the downstream side of the folding mirror 8 or in the vicinity thereof, and the second scanning lens 6b in the sub-scan section. The height of the scanning line on the surface to be scanned 7 is adjusted by adjusting the posture of the folding mirror 8 based on the signal from the sensor 10 (10a, 10b) so that the light beam passes through the substantially optical axis of Or / and the tilt is adjusted.
[0056]
  BookReference exampleThen, the height error and the tilt error of the scanning line caused by the single-piece accuracy and the assembly error due to the folding mirror 8 and the upstream optical components are adjusted on the second scanning lens 6b surface. As a result, the height error or / and the tilt error of the scanning line on the surface to be scanned 7 is only the assembly component of the second scanning lens 6b, and this is within a sufficiently allowable amount. When used in a color image forming apparatus, color misregistration can be reduced.
[0057]
  If the adjustment is not performed, the light beam passes through a position away from the optical axis of the second scanning lens 6b, so that the spot shape on the surface to be scanned 7 is disturbed, rotated, or the like. In contrast to thisReference exampleThen, when the light beam passes substantially on the optical axis of the second scanning lens 6b, the disordered rotation of the spot shape is reduced, and a good spot can be obtained on the scanned surface 7 to form a high-definition image. Can do.
[0058]
  However, this bookReference exampleIf the second scanning lens 6b is assembled with a large error in the height direction, in order to adjust the light flux to be substantially on the optical axis of the second scanning lens 6b, the adjustment method in FIG. The light beam after passing through the second scanning lens 6b is incident on the scanned surface 7 at a position greatly deviated from the desired height position. At this time, if a deviation occurs in the direction in which the incident angle with respect to the surface to be scanned 7 is increased, the jitter in the main scanning direction between the beams when the multi-beam is used increases. Therefore bookReference exampleIs an adjustment method suitable for a scanning optical apparatus using a single beam and a color image forming apparatus using the same.
[0059]
  Book like thisReference exampleAs described above, by adjusting the height or / and the inclination of the scanning line on the scanned surface 7 using the folding mirror 8, for example, when this apparatus is used in a color image forming apparatus, the color misregistration is improved. An image can be obtained.
[0060]
  BookReference exampleThen, although two sensors 10a and 10b are provided in the vicinity of the second scanning lens 6b, more sensors may be provided.
[0061]
  [Reference example 2]
  FIG. 9 shows the present invention.Reference example 2It is principal part sectional drawing (sub-scanning sectional view) of the sub-scanning direction at the time of adjustment. In the figure, the same elements as those shown in FIG.
[0062]
  BookReference exampleThe difference from the first embodiment is that the height or / and the inclination of the scanning line on the scanned surface 7 is adjusted by the folding mirror 8 after all the optical elements constituting the apparatus are assembled to the apparatus main body. And two sensors 10a and 10b as detection means 41 in the main scanning direction on the surface to be scanned 7, and the two sensors 10a and 10b provide a scanning line height error on the surface to be scanned 7 or / And a tilt error is detected. Other configurations and optical actions are substantially the same as those of the first embodiment, and the same effects are obtained.
[0063]
  That is, bookReference exampleThen, the sensor 10 (10a, 10b) for detecting the position of the light beam is arranged only in the main scanning direction in the vicinity of the surface to be scanned 7, and adjusted so that the light beam irradiates a substantially predetermined position on the surface to be scanned 7. The height or / and the inclination of the scanning line on the surface to be scanned 7 is adjusted by adjusting the posture of the folding mirror 8 by the adjusting means based on the signals from (10a, 10b).
[0064]
  BookReference exampleThen, the accuracy of a single product by the optical components in the entire optical system, the height error of the scanning line caused by the assembly error, and the tilt error are adjusted on the scanned surface 7. As a result, the height or / and inclination of the scanning line on the scanned surface 7 is adjusted to a position substantially as designed, so that, for example, when this apparatus is used in a color image forming apparatus, high definition with little color misregistration is achieved. An image can be formed. In addition, since the deviation of the incident angle with respect to the scanned surface 7 is small, the jitter in the main scanning direction between the beams when the multi-beam is used is also reduced and well adjusted.
[0065]
  However, this bookReference exampleIn the adjustment method in, especially when the light beam passes through the second scanning lens 6b on the downstream side of the folding mirror 8, there is a high possibility that the light beam passes through a position away from the optical axis in the sub-scanning section. When the light beam passes through a position away from the optical axis of the second scanning lens 6b, the spot shape on the scanned surface 7 is disturbed, rotated, or the like. BookReference exampleIs an adjustment method suitable for a system having low sensitivity to a scanning line shift by an optical element upstream of the folding mirror 8 or a system in which a strict tolerance is allowed.
[0066]
  Book like thisReference exampleAs described above, by adjusting the height or / and the inclination of the scanning line on the scanned surface 7 using the folding mirror 8, for example, when this apparatus is used in a color image forming apparatus, the color misregistration is improved. An image can be obtained.
[0067]
  BookReference exampleThen, the two sensors 10a and 10b are provided in the main scanning direction on the scanned surface 7, but more sensors may be provided.
[0068]
【The invention's effect】
According to the present invention, as described above, the detection unit detects the height error or / and the tilt error of the scanning line on the surface to be scanned (image carrier surface) due to the accuracy of the optical components in the scanning optical device and the assembly error. Then, the height error or / and the tilt error of the scanning line is suppressed by adjusting the attitude of the folding mirror disposed between the deflecting means and the surface to be scanned based on the detected signal. Thus, a scanning optical device capable of obtaining a high-definition image can be achieved.
[0069]
In addition, according to the present invention, a color image forming apparatus that can obtain a good color image with little color misregistration can be achieved by configuring a color image forming apparatus using a plurality of the scanning optical devices described above.
[Brief description of the drawings]
FIG. 1 is a perspective view of essential parts of Embodiment 1 of the present invention.
FIG. 2 is a sub-scan sectional view of Embodiment 1 of the present invention.
FIG. 3 is a sub-scan sectional view during adjustment according to the first embodiment of the present invention.
FIG. 4 is a perspective view at the time of adjustment according to the first embodiment of the present invention.
FIG. 5 is a diagram showing height adjustment of a scanning line according to the first embodiment of the present invention.
FIG. 6 is a diagram illustrating adjustment of scan line inclination according to the first embodiment of the present invention.
FIG. 7 is a schematic diagram of a main part of a tandem type color image forming apparatus according to a first embodiment of the present invention.
[Fig. 8] of the present inventionReference example 1Sub-scan sectional view during adjustment
FIG. 9 shows the present invention.Reference example 2Sub-scan sectional view during adjustment
FIG. 10 is a schematic diagram of a main part of a conventional scanning optical device.
FIG. 11 is a perspective view of jitter in the main scanning direction.
FIG. 12 is a sub-scanning sectional view of light incident on the image holder.
FIG. 13 is a diagram showing a relationship between a lateral shift amount (incident angle) and a jitter amount.
[Explanation of symbols]
1 Light source means (semiconductor laser)
2 Collimator lens
3 Cylindrical lens
4 Aperture stop
5 Deflection means (rotating polygon mirror)
5a Deflection surface
6 Scanning optical means
6a First scanning lens
6b Second scanning lens
7 Scanned surface (image holding surface)
8 Folding mirror
9 (9a, 9b) Adjustment optical element
10 (10a, 10b) Detection element (sensor)
11 Incident optical means
41 Detection means
41a, 41b detection unit

Claims (3)

A light source means, a deflection means for deflecting and scanning a light beam emitted from the light source means, and a plurality of imaging optical elements for imaging a light beam deflected and scanned by a deflection surface of the deflection means on a surface to be scanned; A scanning optical apparatus comprising: a mirror disposed in an optical path between the plurality of imaging optical elements;
The imaging optical element disposed in the optical path between the deflection surface and the mirror is disposed in the optical path, and the imaging optical element disposed in the optical path between the mirror and the scanned surface is the optical path. In the state where the adjusting optical element is not disposed in the optical path between the mirror and the scanned surface, and the detecting means is disposed at a position where the light beam that has passed through the adjusting optical element is imaged. An error in the height of the scanning line on the surface to be scanned is detected by the detection means, and the mirror is rotated based on an axis parallel to the longitudinal direction of the mirror based on the signal detected by the detection means. By rotating, the height of the scanning line on the surface to be scanned is adjusted, and then an imaging optical element disposed in the optical path between the mirror and the surface to be scanned is attached to the scanning optical device Method for assembling a scanning optical device A light source means, a deflection means for deflecting and scanning a light beam emitted from the light source means, and a plurality of imaging optical elements for imaging a light beam deflected and scanned by a deflection surface of the deflection means on a surface to be scanned; A scanning optical apparatus comprising: a mirror disposed in an optical path between the plurality of imaging optical elements;
The imaging optical element disposed in the optical path between the deflection surface and the mirror is disposed in the optical path, and the imaging optical element disposed in the optical path between the mirror and the scanned surface is the optical path. In the state where the adjusting optical element is not disposed in the optical path between the mirror and the scanned surface, and the detecting means is disposed at a position where the light beam that has passed through the adjusting optical element is imaged. An error in the inclination of the scanning line on the surface to be scanned is detected by the detecting means, and the mirror is set based on a signal detected by the detecting means with an axis parallel to the short direction of the mirror as a rotation axis. By rotating, the inclination of the scanning line on the surface to be scanned is adjusted, and then an imaging optical element disposed in the optical path between the mirror and the surface to be scanned is attached to the scanning optical device. For assembling a scanning optical device The light source means emits a plurality of light beams, and a plurality of scanning lines are simultaneously formed on the surface to be scanned by the plurality of light beams emitted from the light source means. 3. A method of assembling the scanning optical device according to 2.