JP2002310852A - Optical characteristic measuring device and optical characteristic measuring method for scanning optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring device and a measuring method capable of automatically measuring a characteristic of a light spot in an optical system scanning by respectively condensing a plurality of laser beams as light spots on different planes to be scanned. SOLUTION: The light spot characteristic is inspected in a desired a main scanning direction position on a plane to be inspected of the scanning optical system respectively condensing the plurality of light beams A and B as the light spots on the different planes to be inspected. Photosensors 5, 11, and 14 are provided arranged so light receiving faces match with the planes to be inspected for measuring a characteristic value of each light spot at desired main scanning direction positions which are measurement points. A moving means is provided comprising stages 6 and 7 two-dimensionally moving the photosensors, a rotating stage 8 capable of rotating the photosensors, or a stage three-dimensionally moving the photosensors, or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light spot in an optical system (hereinafter referred to as a "tandem optical system") for converging a plurality of laser beams as light spots on different scanning surfaces and scanning at a constant speed. For measuring various characteristics such as scanning position, magnification error, beam spot diameter, beam profile, beam power, calorific value, spot position in the sub-scanning direction, etc. About.

[0002]

2. Description of the Related Art An optical scanning optical system which focuses a laser beam as a light spot on a surface to be scanned, scans the surface to be scanned at a constant speed, and writes an image on the surface to be scanned, employs an electrophotographic process. It is used in a copying machine to be used, other various image reading apparatuses, and various image forming apparatuses using this image reading apparatus. In recent years, high-speed image forming apparatuses have been demanded, and in order to cope with this, a tandem scanning optical system has been developed in which a plurality of laser beams are respectively condensed as light spots on different scanned surfaces. The tandem optical system is mainly used in a color image forming apparatus, and different scanning surfaces of photosensitive members are arranged on different scanning surfaces.

In a tandem scanning optical system, it is necessary that the optical characteristics of light spots converged on a surface to be scanned by respective light beams are uniform, and therefore, it is necessary to measure the optical characteristics of each light spot. There is. The measured light spot characteristics include a scanning position, a magnification error, a beam spot diameter, a beam profile, a beam power, a calorific value, and a spot position in the sub-scanning direction. In the case of the tandem optical system, the relative displacement of the spot position in the sub-scanning direction of each light beam appears in the image as a dot position displacement, and thus the spot position in the sub-scanning direction is an important characteristic value.

[0004]

Conventionally, each of the above characteristic values is measured by an independent measuring device, or the same measuring device is used by replacing a sensor for each characteristic value, or is measured by each measuring position. The sensor was reset and measured. Further, the sensor was fixed at a preset position. As a result, the measuring device becomes large,
Alternatively, since it is necessary to reset the sensor for each measurement position and perform the measurement, it takes a long time to measure, and, for example, the spot position variation in the sub-scanning direction of each deflecting and reflecting surface of an optical deflector such as a rotating polygon mirror. , It was difficult to make accurate measurements.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem of the prior art, and the inventions according to claims 1 and 10 disclose a plurality of laser beams on different scanning surfaces. It is an object of the present invention to provide a measuring apparatus and a measuring method capable of automatically measuring characteristics of a light spot in an optical system that scans by condensing and scanning a light spot.

It is an object of the present invention to automatically measure a plurality of characteristics of a light spot. A fourth object of the present invention is to make it possible to measure the characteristics of a light spot from any position and any direction. It is an object of the present invention to prevent a rise in component cost due to an improvement in sensor mounting accuracy and reduce the cost.

Another object of the present invention is to provide a measuring device in a tandem optical system which can measure a light spot position in the sub-scanning direction by a single sensor. It is an object of the present invention to provide a measuring apparatus and a measuring method capable of accurately measuring a light spot position in the sub-scanning direction in a short time in a tandem optical system.

An object of the present invention is to accurately calculate the displacement amount of the light spot in the sub-scanning direction by calculating all the combinations from the measurement results of the light spot position in the sub-scanning direction in the tandem optical system. And Claim 9
An object of the invention described above is to accurately measure a light spot position in the sub-scanning direction by setting a shake amount during movement of a sensor movement stage as a correction value.

[0009]

According to the first aspect of the present invention,
An optical characteristic measuring device for measuring a light spot characteristic at a desired position in a main scanning direction on a scanned surface of a scanning optical system for condensing a plurality of laser beams as light spots on different scanned surfaces. In order to measure the characteristic value of each light spot at a desired position in the main scanning direction as a measurement point, an optical sensor arranged so that a light receiving surface coincides with the surface to be scanned, and the optical sensor is two-dimensionally arranged. And a moving means capable of moving the moving object.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of optical sensors are disposed in a rotating direction, and the light receiving surface of each optical sensor coincides with a measurement surface equivalent to the surface to be scanned by the rotation. And a moving means capable of moving the rotating stage two-dimensionally. According to a third aspect of the present invention, in the first aspect of the present invention, a plurality of optical sensors are provided and the stage is movable at least in the main scanning direction.
Moving means capable of moving in a three-dimensional manner.

According to a fourth aspect of the present invention, in the first aspect of the present invention, there is provided a moving means capable of moving the sensor three-dimensionally, a moving means capable of moving the sensor in a rotating direction, and a moving means capable of moving the sensor in a tilting direction. Moving means that can be moved. According to a fifth aspect of the present invention, in the second aspect of the present invention, each of the optical sensors is provided via a position adjusting means so that each position can be adjusted independently.

According to a sixth aspect of the present invention, there is provided a scanning optical system for converging a plurality of laser beams as light spots on different scanning surfaces, respectively, at a desired position in the main scanning direction on the scanning surface. An optical characteristic measuring device for measuring characteristics, wherein a single sensor capable of measuring a sub-scanning direction position of a light spot at a main scanning position serving as a measuring point, and this sensor is arranged on a surface to be scanned of each laser beam. A moving unit that can be two-dimensionally moved so as to match a desired position in the main scanning direction.

According to a seventh aspect of the present invention, there is provided a scanning optical system for condensing a plurality of laser beams as light spots on different scanning surfaces, respectively, at a desired position in the main scanning direction on the scanning surface. An optical characteristic measuring device for measuring characteristics, wherein a sensor capable of measuring a sub-scanning direction position of a light spot at a main scanning direction position serving as a measurement point is provided for each laser beam, and each sensor is provided on a surface to be scanned of the laser beam. A moving means that can be one-dimensionally moved so as to be able to match a desired position in the main scanning direction in the above.

The invention according to claim 8 is the invention according to claim 6 or 7.
In the described invention, the sub-scanning position of each light spot by a plurality of laser light beams is obtained for each deflection reflection surface of the optical deflector at a desired main scanning direction position, and the light spot of each laser light beam at the same main scanning direction position is obtained. The position is compared for all combinations of the deflection reflecting surfaces to determine the amount of displacement in the sub-scanning direction of each laser beam. According to a ninth aspect of the present invention, in the invention of the eighth aspect, the amount of deflection of the light spot in the sub-scanning direction due to each laser beam at a desired position in the main scanning direction is a correction value of the light spot position in the sub-scanning direction. And

According to a tenth aspect of the present invention, there is provided a scanning optical system for condensing a plurality of laser beams as light spots on different scanning surfaces, respectively, at a desired position in the main scanning direction on the scanning surface. An optical characteristic measuring method for measuring a characteristic, wherein an optical sensor arranged such that a light receiving surface coincides with the surface to be scanned is used, and the optical sensor is moved two-dimensionally to obtain a desired measurement point. The characteristic value of each light spot is measured at the position in the main scanning direction.

According to an eleventh aspect of the present invention, there is provided a scanning optical system for converging a plurality of laser beams as light spots on different scanning surfaces, respectively, at a desired position in the main scanning direction on the scanning surface. An optical characteristic measuring method for measuring characteristics, wherein a sensor provided for each laser beam so as to be able to measure a position of a light spot in a sub-scanning direction at a desired position in a main scanning direction, which is a measurement point, is used.
The characteristic value of each light spot is measured by moving the laser beam in a desired main scanning direction on the surface to be scanned by moving it in a three-dimensional manner.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an optical characteristic measuring apparatus and an optical characteristic measuring method for a scanning optical system according to the present invention will be described with reference to the drawings. FIG. 1 is a side view showing a first embodiment of the light spot characteristic measuring device. In FIG. 1, an appropriate number of columns 110 are erected on the measuring instrument base 100, and the optical scanning unit 200 is supported by the columns 110. The optical scanning unit 200 includes a laser light source such as a semiconductor laser (not shown) that emits two laser beams A and B, and a rotary polygon mirror 1 that deflects and reflects the laser beams A and B.
And the laser beam A, which is deflected and reflected by the rotating polygon mirror 1,
Fθ lens 2 as an operation imaging lens for converging B as a light spot on the surface to be scanned and scanning the light spots of the laser beams A and B at a constant speed on the surface to be scanned;
It has folding mirrors 3 and 4 for guiding the laser beams A and B passing through the θ lens 2 to different scan surfaces.

A Y stage 6 capable of moving an object in the Y direction (left and right directions in FIG. 1) is installed on the measuring instrument base 100, and the object is moved on the Y stage 6 in the moving direction of the Y stage. An X stage 7 is provided which is movable in an X direction perpendicular to FIG. 1 and perpendicular to the plane of FIG. On the X stage 7, a single optical sensor 5 is installed obliquely so that the laser beams A and B reflected by the mirrors 3 and 4 can be received. The optical sensor 5 is arranged so that its light receiving surface is equivalent to the surface to be scanned by the laser spot, in other words, so as to coincide with the surface to be scanned. The X direction is a scanning direction of the laser beams A and B by the rotation of the rotary polygon mirror 1, that is, a main scanning direction, and the Y direction is a sub scanning direction orthogonal to the X direction. The X stage 7 and the Y stage 6 constitute a moving unit that can move the optical sensor 5 two-dimensionally.

With the X stage 7, the optical sensor 5 can be moved in the main scanning direction, and the light receiving surface of the optical sensor 5 can be arranged at a desired position in the main scanning direction on the surface to be scanned. Further, the optical sensor 5 can be moved in the sub-scanning direction by the Y stage 6. The laser beam A,
B is reflected by the folding mirrors 3 and 4 and condensed on the light receiving surface of the optical sensor 5 disposed at a position corresponding to the image plane. The optical sensor 5 receives the light beam A at an arbitrary position in the main scanning direction of the light beam A by an X stage movable in the main scanning direction, and measures various optical characteristics of the light spot. The optical sensor 5 is moved by the Y stage in the sub-scanning direction orthogonal to the main scanning direction, and is arranged at the light condensing position of the light beam B.
The stage 7 receives the light beam B at an arbitrary position in the main scanning direction of the light beam B, and measures various optical characteristics of the light spot. The measurement items include a scanning position, a magnification error, a beam spot diameter, a beam profile, a beam power, a calorific value, and a spot position in the sub-scanning direction.

FIG. 2 is a plan view of the sensor section of the second embodiment, and FIG. 3 is a side view of the second embodiment. The X stage 7 is on the Y stage 6, and the rotating stage 8 is on the X stage 7.
Is attached. A plurality of sensors, in this example, four sensors 11, 12, 13, 1
4 is arranged in the rotation direction of the rotary stage 8. When the rotary stage 8 rotates, each sensor 11, 1
The light receiving units 2, 13, and 14 can be moved to the same light condensing position. The sensors 11, 12, 13, and 14 can measure, for example, the various items described above.
Sensors that measure the light spot diameter using the slit scanning method, one-dimensional CCD-type scanning line position measurement sensors, magnification error measurement sensors that use a time interval counter, area CCD camera-type beam profilers, and photodiode-type optical power meters And a pyroelectric element type Joule meter. In this way, the rotating stage 8 is added to the moving means that can move two-dimensionally as shown in FIG.

According to the embodiment shown in FIGS. 2 and 3, each optical sensor 11, 12, 13, 14 is
Can be arranged so that a light beam can be received at an arbitrary position in the main scanning direction. Then, the optical sensor suitable for the measurement item is selected and positioned on the optical path of the laser beam by the rotation stage 8, and the optical characteristics of the desired item can be measured.

FIG. 4 is a front view of a sensor section according to a third embodiment of the present invention. The X stage 7 is mounted on the Y stage 6, and four optical sensors 21 and 2 are mounted on the X stage 7.
2, 23 and 24 are arranged in the X direction. The Y stage 6 and the X stage 7 constitute a moving unit that can move the sensor two-dimensionally. By driving the X stage 7, each of the sensors 21, 22, 23, 24
Can be moved to the same condensing position. According to this embodiment, the same measurement as the embodiment shown in FIGS. 2 and 3 can be performed.

FIG. 5 is a side view of a sensor unit according to a fourth embodiment of the present invention. In FIG. 5, an X stage 7 is on a Y stage 6, a Z stage 10 is on an X stage 7,
A rotary stage 8 is mounted on the Z stage 10, a tilt stage 20 is mounted on the rotary stage 8, and a single optical sensor 5 is mounted on the tilt stage 20. The Z stage 10 is movable in a vertical direction which is a direction orthogonal to the XY directions. The tilt stage 20 can change the tilt angle while moving the optical sensor 5 while drawing an arc by moving in an arc on a vertical plane. The Y stage 6, the X stage 7, and the Z stage 10 constitute a moving unit that can move the optical sensor 5 three-dimensionally.

According to the embodiment shown in FIG. 5, by driving each of the above-mentioned stages, the light receiving section of the optical sensor 5 can be moved in all directions and the inclination angle can be adjusted. For this reason, even if the condensing positions of the plurality of laser beams or the positions of the surfaces to be scanned in the tandem scanning optical system are not on the same plane, even if the irradiation angles are different,
It can correspond to the measurement of various optical characteristics of the scanning optical system.

FIG. 6 is a plan view of a sensor section according to a fifth embodiment of the present invention. The plurality of sensors 21, 22, 23, and 24 are respectively disposed on separate stages 31, 32, 33, and 34, and each of the stages 31, 32, 33, and 34 is mounted on the X stage 7. Each stage 31,
32, 33, and 34 can move the sensors 21, 22, 23, and 24 independently in the X direction and the Y direction. By driving the X stage 7, each of the sensors 21, 22,
23 and 24 can be arranged at desired positions in the main scanning direction. Further, a stage 3 supporting each of the sensors 21, 22, 23, 24 arranged at a desired position in the main scanning direction.
By individually moving 1, 32, 33, and 34 in the XY directions, fine adjustments can be made so that the positions of the light receiving surfaces of the sensors 21, 22, 23, and 24 match. For this reason, the mounting positions of the sensors 21, 22, 23, and 24 may be relatively rough, and there is an advantage that the preparation work for the measurement and the maintenance are facilitated. Each of the stages 31, 32, 33, 34 is provided with a corresponding one of the sensors 21, 22, 2,
It functions as an adjusting means that can adjust the positions of 3, 24 independently.

FIG. 7 shows a side view of a sixth embodiment of the present invention. 7, the optical scanning unit 200 has four laser light sources (not shown), and the four laser light sources emit laser beams A, B, C, and D, respectively. Two of the four laser beams A, B, C, D
The two laser beams A and B are deflected and reflected to the left of the rotary polygon mirror 1 in FIG. 7, and the other two laser beams C and D are deflected and reflected to the right of the rotary polygon mirror 1 in FIG. The laser beams A and B pass through the fθ lens 51 and are
The light is reflected by 1, 42 and condensed at a position corresponding to the surface to be scanned. The other two laser beams C and D pass through the fθ lens 52, are reflected by the turning mirrors 43 and 44, and are condensed at a position corresponding to the surface to be scanned. Each laser beam A, B,
The surfaces to be scanned on which C and D converge are different from each other, and in an image forming apparatus in which the optical scanning unit 200 is incorporated, the surface of an image carrier made of a different photosensitive member corresponding to each laser beam is scanned. Surface.

A light receiving surface of the optical sensor 5 is provided at a position corresponding to the surface to be scanned, and a laser beam is focused on this light receiving surface. The optical sensor 5 is mounted on the rotary stage 8 in a posture inclined at a predetermined angle. Rotary stage 8
Is mounted on the X stage 7, and the X stage 7 is mounted on the Y stage.
The Y stage 6 is mounted on the measuring instrument base 100. X stage 7
The Y stage 6 and the Y stage 6 constitute moving means for moving the optical sensor 5 two-dimensionally.

In the embodiment shown in FIG. 7, the optical sensor 5 is first moved to, for example, a desired position in the main scanning direction of the laser beam A by the X stage 7 movable in the main scanning direction, and the laser beam is positioned. A is received by the optical sensor 5 and the optical characteristics of the light spot of the laser beam A are measured.
The sensor 5 is provided with a laser beam B, C or D by a Y stage 6 which can move in a direction perpendicular to the main scanning direction.
Since the optical sensor 5 can be moved to the light condensing position, the sensor 5 is moved to the light receiving position of each laser light beam, and further moved to the desired main scanning direction position of each laser light beam by the X stage 7 for positioning. Then, the optical characteristics of each laser beam are measured.

In the embodiment shown in FIG. 7, the laser beams A,
B and the laser beams C and D have different irradiation angles with respect to the surface to be scanned. Therefore, when the optical characteristics of the laser beams C and D are to be measured, the optical sensor 5 is rotated by 180 degrees by the rotating stage 8 so that the incident angle with respect to the optical sensor 5 is changed to the incident angle when the laser beams A and B are measured. And the same as Here, as the optical sensor 5, for example, a line CCD in which pixels are arranged in the sub-scanning direction is used. The position of the light spot in the sub-scanning direction can be determined by calculating the position of the center of gravity of the light beam incident on the line CCD from the received light intensity of each pixel of the CCD.

FIG. 8 shows a side view of a seventh embodiment of the present invention. In FIG. 8, an optical scanning unit 200 is a tandem scanning optical system using four laser light beams and configured similarly to that shown in FIG. Each laser beam A, B, C, D
, Four optical sensors 21, 22, 23, and 24 are provided, and the four optical sensors 21, 22, 23, and 24 are provided.
Are independent X stages 61, 62, 63, 64
Is moved and positioned at a desired position in the main scanning direction, and the optical characteristics of the light spots of the laser beams A, B, C, and D are measured at that position. In this embodiment, the moving means for moving the sensor is only the X stage, and moves the sensor one-dimensionally.
Light sensors 21, 22, 23, 24 are used, and these light sensors are independent X stages 61, 62, 6, respectively.
Since the laser beam can be moved to a desired position in the main scanning direction by 3 and 64, the light receiving surface of each optical sensor should be arranged in accordance with the desired position in the main scanning direction of each laser beam on the surface to be scanned. The optical characteristic value of the light spot of each laser beam can be obtained.

FIG. 9 shows an example of the result of the measurement as described above. In this example, there are four laser beams, six deflecting and reflecting surfaces of the rotary polygon mirror, and the main scanning direction measurement position is -100 mm, 0 mm, 100 m
m. “Polygon surface NO” indicates the deflecting and reflecting surfaces of the rotary polygon mirror in order. The values in the table are the positions of the centers of gravity of the light beams, and the relative values with the center of gravity position at 0 in the main scanning direction being 0 are expressed in units of μm for easy comparison. For example, the light spot position in the sub-scanning direction of the light beam 1 (corresponding to the light beam A in the above example) due to the deflecting reflection surface NO1 of the rotary polygon mirror is shifted by -50 μm at the position of −100 mm in the main scanning direction, and conversely, in the main scanning direction. Direction position 100m
In the case of m, the shift is 50 μm.

In an actual image forming apparatus using this optical system, it is not known on which deflection reflecting surface the adjacent write lines were written. Therefore, the main scanning direction position 0
If the position of each laser beam is adjusted so as to be optimal, the relative displacement between the beam 1 and the beam 2 adjacent thereto becomes the largest because the beam 1 and the deflecting / reflecting surface NO5 at the main scanning position of -100 mm. It can be seen that the displacement amount is −60 − (− 23) = 37 (μm) for the combination of the light beam 2 and the deflection / reflection surface 3. Similarly, when all combinations are examined, the relative deviation between adjacent light beams is maximized in the combination of the light beam 3 and the deflecting reflecting surface 3 and the light beam 4 and the deflecting reflecting surface 5 at the main scanning position of -100 mm. It can be seen that the shift amount is 60 μm. Therefore, the displacement amount of the light spot in the sub-scanning direction in this optical system is 60 μm at the maximum.

In the light spot optical characteristic measuring apparatus shown in FIG. 7, since there is one X stage, even if the stage has a bend, the measured value is a relative value between each light beam, and there is no problem. . However, in the light spot optical characteristic measuring device shown in FIG. 8, since there are a plurality of X stages, if the stage has a bend or the like, the measurement accuracy is reduced. Therefore, in advance, the position deviation amount in the sub-scanning direction is measured and obtained by comparing the light spot position in the measurement main scanning direction position of the stage with all combinations of the deflection reflection surfaces as described above. The fluctuation amount of the light spot in the sub-scanning direction due to the light beam is included as a correction value of the spot position in the sub-scanning direction. By doing so, it is possible to prevent the above-described decrease in measurement accuracy.

[0034]

According to the first and tenth aspects of the present invention, there is provided an optical system for converging and scanning a plurality of laser beams as light spots on different surfaces to be scanned.
The optical characteristics of the light spot can be automatically measured.

According to the second aspect of the present invention, by disposing a plurality of optical sensors on the rotary stage in the circumferential direction, it is possible to automatically measure a plurality of characteristics of the light spot.

According to the third aspect of the present invention, it is possible to automatically measure a plurality of characteristics of a light spot by installing a plurality of optical sensors on a stage movable along the main scanning direction. Becomes

According to the fourth aspect of the present invention, the sensor is
By being provided so as to be movable in the dimensional direction, the rotation direction, and the tilt direction, it is possible to measure the optical characteristics of the light spot from any position and direction.

According to the fifth aspect of the present invention, the position of each optical sensor can be adjusted independently, so that the mounting position accuracy of each sensor can be roughened.
Parts costs can be reduced.

According to the sixth aspect of the present invention, in an optical system for converging and scanning a plurality of laser beams as light spots on different scanning surfaces, respectively, a sensor is provided on the scanning surface of each laser beam. The two-dimensionally movable parts can be measured in the sub-scanning direction between a plurality of laser beams so as to be able to match the desired position in the main scanning direction.

According to the seventh and eleventh aspects of the present invention,
In an optical system for converging and scanning a plurality of laser light beams as light spots on different scanned surfaces, a sensor is provided for each laser light beam, and each sensor is provided in a desired main scanning direction on the scanned surface of the laser light beam. By providing one-dimensionally movable so as to match the position, it is possible to measure the amount of displacement of the laser beam in the sub-scanning direction in a short time.

According to the eighth aspect of the present invention, the position of the light spot at the same main scanning position of each laser light beam is compared for all combinations of the deflecting and reflecting surfaces, so that each laser light beam is displaced in the sub-scanning direction. The maximum value of the quantity can be determined.

According to the ninth aspect of the present invention, the amount of fluctuation in the sub-scanning direction at the main scanning position of each sensor moving means is set as a correction value of the light spot position in the sub-scanning direction, so that the position of the laser beam in the sub-scanning direction is corrected. The shift amount can be obtained with high accuracy.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of an optical characteristic measuring device and an optical characteristic measuring method of a scanning optical system according to the present invention.

FIG. 2 is a plan view showing an optical sensor part of a second embodiment of an optical characteristic measuring device and an optical characteristic measuring method of a scanning optical system according to the present invention.

FIG. 3 is a side view of an optical sensor according to the first embodiment.

FIG. 4 is a side view showing an optical sensor part of a third embodiment of the optical characteristic measuring device and the optical characteristic measuring method of the scanning optical system according to the present invention.

FIG. 5 is a side view showing an optical sensor part of a fourth embodiment of an optical characteristic measuring device and an optical characteristic measuring method of a scanning optical system according to the present invention.

FIG. 6 is a side view showing an optical sensor part of a fifth embodiment of an optical characteristic measuring device and an optical characteristic measuring method of a scanning optical system according to the present invention.

FIG. 7 is a side view showing a sixth embodiment of the optical characteristic measuring device and the optical characteristic measuring method of the scanning optical system according to the present invention.

FIG. 8 is a side view showing a seventh embodiment of an optical characteristic measuring device and an optical characteristic measuring method for a scanning optical system according to the present invention.

FIG. 9 is a diagram showing an example of a measurement result according to the embodiment.

[Explanation of symbols]

 A, B, C, D Laser beam 1 Rotating polygon mirror 2 fθ lens 3, 4 Folding mirror 5 Optical sensor 6 Y stage 7 X stage 8 Rotating stage 10 Z stage 11, 12, 13, 14 Optical sensor 20 Tilt stage 21, 22,23,24 Optical sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/113 H04N 1/04 104A 5C072 F term (Reference) 2C362 AA03 AA07 AA20 AA28 AA36 2F065 AA03 AA19 FF49 GG04 JJ01 JJ03 JJ25 JJ26 LL15 LL28 MM14 MM24 MM25 PP02 PP04 2G086 HH07 2H045 BA22 BA33 BA34 CA82 DA31 5C051 AA02 CA07 DB02 DB30 FA00 5C072 AA03 BA20 HA02 HA13 HB20 XA10

Claims (11)

[Claims] 1. A scanning optical system for converging a plurality of laser beams as light spots on different scanning surfaces, respectively.
An optical property measuring apparatus for measuring a light spot characteristic at a desired main scanning direction position on the surface to be scanned, wherein a characteristic value of each light spot is measured at a desired main scanning direction position serving as a measurement point. An optical characteristic of a scanning optical system, comprising: an optical sensor arranged so that a light receiving surface thereof coincides with the surface to be scanned; and a moving unit capable of moving the optical sensor two-dimensionally. measuring device. 2. A plurality of optical sensors are arranged in a rotation direction,
A rotation stage arranged at a measurement position in the main scanning direction so that a light receiving surface of each optical sensor coincides with a measurement surface equivalent to a surface to be scanned by rotation; and a moving means capable of moving the rotation stage two-dimensionally. The optical characteristic measuring device for a scanning optical system according to claim 1, further comprising: 3. A stage provided with a plurality of optical sensors, comprising: a stage capable of moving at least in the main scanning direction; and a moving means capable of moving the stage two-dimensionally. The optical characteristic measuring device for a scanning optical system according to claim 1. 4. A moving device capable of moving a sensor three-dimensionally, a moving device capable of moving in a rotation direction, and a moving device capable of moving a sensor in an inclined direction. 2. An apparatus for measuring optical characteristics of a scanning optical system according to claim 1, wherein: 5. The optical characteristic measurement of a scanning optical system according to claim 2, wherein each of the optical sensors is provided via a position adjusting means so that each position can be adjusted independently. apparatus. 6. A scanning optical system for converging a plurality of laser beams as light spots on different scanning surfaces, respectively.
An optical property measuring device for measuring a light spot characteristic at a desired position in the main scanning direction on the surface to be scanned, wherein the single device is capable of measuring the position of the light spot in the sub-scanning direction at a main scanning position serving as a measurement point. A sensor, and a moving means capable of two-dimensionally moving the sensor so as to match a desired main scanning direction position of the laser beam on the surface to be scanned. Optical characteristic measuring device for scanning optical system. 7. A scanning optical system for converging a plurality of laser beams as light spots on different scanning surfaces, respectively.
An optical characteristic measuring device for measuring a light spot characteristic at a desired position in the main scanning direction on the surface to be scanned, wherein a laser capable of measuring the position of the light spot in the sub-scanning direction at a main scanning direction position serving as a measurement point is a laser. A moving means is provided for each light beam, and is capable of moving each sensor one-dimensionally so as to be able to match a desired position of the laser light beam on the surface to be scanned in the main scanning direction. Optical characteristic measuring device for scanning optical system. 8. A sub-scanning direction position of each light spot by a plurality of laser light beams is obtained for each deflecting reflection surface of an optical deflector at a desired main scanning direction position, and a light spot of each laser light beam at the same main scanning direction position is obtained. By comparing the positions of all combinations of the deflection reflecting surfaces,
8. The optical characteristic measuring apparatus for a scanning optical system according to claim 6, wherein a positional shift amount of each laser beam in the sub-scanning direction is obtained. 9. The scanning optical system according to claim 8, wherein the amount of fluctuation of the light spot in the sub-scanning direction by each laser beam at a desired position in the main scanning direction is used as a correction value of the light spot position in the sub-scanning direction. Optical property measuring device. 10. An optical characteristic for measuring a light spot characteristic at a desired position in the main scanning direction on a scanned surface of a scanning optical system for converging a plurality of laser beams as light spots on different scanned surfaces. A measuring method, wherein an optical sensor arranged so that a light receiving surface coincides with the surface to be scanned is used, and the optical sensor is moved two-dimensionally to obtain a desired measuring point at a main scanning direction position. A method for measuring optical characteristics of a scanning optical system, comprising: measuring a characteristic value of each light spot. 11. An optical characteristic for measuring a light spot characteristic at a desired position in the main scanning direction on a scanned surface of a scanning optical system for condensing a plurality of laser beams as light spots on different scanned surfaces. A measurement method, comprising: using a sensor provided for each laser beam so as to measure a sub-scanning direction position of a light spot at a desired main scanning direction position to be a measurement point, and moving these sensors in one dimension. And measuring a characteristic value of each light spot in accordance with a desired position of the laser beam on the surface to be scanned in the main scanning direction.