JP2008158317A - Device for inspecting scanning optical system, and method of inspecting scanning optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for inspecting a scanning optical system capable of performing total performance at a time. <P>SOLUTION: The device performs: imaging a laser beam L on a face to be scanned 13 with CCD sensors 51a-51c; controlling the operation of a laser light source 22 with an APC circuit 28 so as each of 6-deflection reflection face 33 is irradiated with the laser beam L; analyzing data of images obtained by each CCD sensor; and calculating the irradiation position of the laser beam L on the face to be scanned 13 with an irradiation position calculation circuit 70. A parameter calculation circuit 71 calculates each parameter of a face fall amount of the deflection reflection face 33 and a jitter component, and a shift amount of an angle making the face to be scanned 13 and an optical axis of the laser beam L from calculation results of the irradiation position before and after moving the CCD sensor 51b on a moving stage 53 in a direction of the optical axis of the laser beam L. A determination circuit 72 determines the results by comparing each calculated parameter with a regulation value and displays the determination results on a monitor 54. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a scanning optical system inspection apparatus and a scanning optical system inspection method for confirming the performance of a scanning optical system.

  Scanning optical systems include image recording devices such as laser printers, copiers, and facsimiles, as well as radiation (X-rays, α, β, γ rays, electron beams) recorded on a storage phosphor sheet (imaging plate; IP). It is also mounted on CR (Computed Radiography) devices that read images (such as ultraviolet rays) and output the read images to a monitor or negative film.

  The scanning optical system has various optical elements such as a laser light source, a collimator lens, an imaging optical system including a diaphragm and a cylindrical lens, a polygon mirror, and an fθ lens, and these are stored as one unit in an optical box. It is configured. In the scanning optical system, a laser beam is emitted from a laser light source in accordance with image data to be recorded. The laser beam is converged into a parallel light beam by a collimator lens and condensed linearly by an imaging optical system. Then, the light is reflected by the deflecting / reflecting surface of the polygon mirror and imaged on the surface to be scanned by the fθ lens.

  The laser beam focused on the surface to be scanned is scanned (main scan) on the surface to be scanned because the polygon mirror is rotated at a constant angular velocity. When used in an image recording apparatus such as a laser printer, a copying machine, or a facsimile, the recording material, for example, the photosensitive member is moved by moving a recording material, for example, the photosensitive member in a direction orthogonal to the main scanning direction (sub-scanning direction). An electrostatic latent image by a laser beam is recorded on the surface. Then, the electrostatic latent image recorded on the photosensitive member is visualized as a toner image and transferred to a recording medium such as recording paper.

  On the other hand, when used in a CR apparatus, main scanning is performed with a laser beam while conveying the stimulable phosphor sheet on which the radiation image is recorded in the sub-scanning direction. Then, the stimulated emission light generated thereby is detected by a photoelectric converter such as a photomultiplier to obtain an image signal.

  By the way, as a cause of deterioration of a recorded image or an image signal by the scanning optical system, the deflection reflection surface of the polygon mirror is tilted (inclination of the deflection reflection surface with respect to the rotation axis) and jitter (the deflection reflection surface is projected and retracted from the rotation center) The laser beam may deviate from the normal irradiation position due to a shift in the falling angle (laser beam irradiation angle with respect to the surface to be scanned). For this reason, conventionally, a method has been proposed in which a laser beam on a surface to be scanned is imaged by a CCD sensor, and the captured image is monitored to measure the deviation of the irradiation position of the laser beam (see Patent Documents 1 and 2). ).

In Patent Document 1, two line sensors are arranged close to each other on the surface to be scanned so that pixels of each sensor are shifted from each other by 1/2 pitch in the sub-scanning direction, and images are formed on the line sensors for each surface of the polygon mirror. It is described that the amount of surface tilt is measured by obtaining and comparing the position of the beam. Further, in Patent Document 2, a CCD area sensor is arranged at an arbitrary position on a surface to be scanned with a pixel row obliquely positioned, and a beam shape is measured with a CCD sensor for each surface of a polygon mirror. It is described that the amount of trouble is calculated.
Japanese Patent Laid-Open No. 11-304642 JP 2000-304607 A

  However, the inventions described in Patent Documents 1 and 2 have a problem in that a comprehensive performance inspection cannot be performed because only the measurement of the surface tilt amount is performed and the deviation amount of the jitter component and the falling angle is not measured. was there.

  SUMMARY An advantage of some aspects of the invention is that it provides a scanning optical system inspection apparatus and a scanning optical system inspection method capable of performing a comprehensive performance inspection at a time.

  In order to achieve the above object, the present invention provides a scanning in which an optical element including a deflector having a plurality of deflecting reflection surfaces for deflecting and reflecting a light beam from a light source toward a surface to be scanned is accommodated in an optical box. An apparatus for inspecting an optical system, the light source control for controlling the operation of the light source so that the light beam is irradiated to each of the plurality of deflection reflection surfaces to the rotationally driven deflector Obtained by the imaging means, an imaging means arranged on the scanned surface and imaging the light beam on the scanned surface, a moving means for moving the imaging means in the optical axis direction of the light beam, and Analyzing the image data and calculating the irradiation position of the light beam on the surface to be scanned, and from the calculation results of the irradiation position calculation means, Jitter components, line A parameter calculating means for calculating each parameter of the amount of deviation of the angle between the scanned surface and the optical axis of the light beam, and a determining means for comparing the calculated parameters and a standard value to determine pass / fail; And display means for displaying the determination result of the determination means.

  It is preferable that the parameter calculation unit obtains the surface tilt amount from a deviation amount of the irradiation position in a sub-scanning direction orthogonal to a main scanning direction in which the light beam is scanned.

  It is preferable that the parameter calculation unit obtains the jitter component from a deviation amount of the irradiation position in the main scanning direction in which the light beam is scanned.

  The parameter calculation unit is configured to compare the light beam calculated from the image data obtained by the imaging unit before and after being moved by the moving unit with respect to a main scanning direction in which the light beam is scanned. It is preferable to obtain the angular deviation amount from the irradiation position in the orthogonal sub-scanning direction and the movement amount of the imaging means by the movement means.

  It is preferable to provide operation input means for changing the setting of the standard value.

  The irradiation position calculation means detects the luminance value of each pixel of the imaging means constituting the image data, creates a luminance value distribution of each pixel for each vertical and horizontal pixel arrangement, and the luminance value peaks. It is preferable to calculate the position of the pixel as the irradiation position of the light beam.

  Preferably, the irradiation position calculation means averages the irradiation positions of the light beams calculated from the image data for a plurality of frames, and finally outputs an average value.

  It is preferable that a plurality of the imaging means are arranged at equal intervals along the scanning direction of the light beam.

  According to a ninth aspect of the present invention, there is provided a scanning optical system in which an optical element including a deflector having a plurality of deflection reflection surfaces for deflecting and reflecting a light beam from a light source toward a surface to be scanned is housed in an optical box. A method of inspecting, wherein the rotating deflected deflector is irradiated with the light beam for each of the plurality of deflecting reflecting surfaces, and an imaging unit disposed on the scanned surface, Imaging the light beam on the surface, moving the imaging means in the direction of the optical axis of the light beam, analyzing the image data obtained by the imaging means, and analyzing the light on the surface to be scanned The step of calculating the irradiation position of the beam, and the calculation result of the irradiation position, the surface tilt amount and jitter components of the plurality of deflecting reflection surfaces, and the angle deviation between the scanned surface and the optical axis of the light beam Calculate each parameter of quantity A step, by comparing the parameters and standards values calculated, characterized by comprising the step of determining acceptability, and a step of displaying the determination result.

  According to the scanning optical system inspection apparatus and the scanning optical system inspection method of the present invention, the light beam is irradiated to each of the plurality of deflection reflection surfaces of the rotationally driven deflector, and the light beam on the surface to be scanned is imaged. From the obtained image data, the irradiation position of the light beam on the surface to be scanned is calculated, the surface tilt amount and the jitter component are obtained from the calculation result, and the imaging means is moved in the optical axis direction of the light beam. Since the amount of fall of the falling angle is obtained from the image data picked up and moved, the pass / fail of each of these parameters is determined, and the determination result is displayed, so that a comprehensive performance test can be performed at a time. Therefore, the inspection time can be greatly shortened.

  In FIG. 1, the radiation image reading apparatus 2 includes a scanning optical system 10, a reading unit 11, a transport system for transporting the stimulable phosphor sheet 12, a control unit including various signal processing circuits, and the like. It has the structure mounted in. The radiation image reading apparatus 2 is provided with an insertion port into which a cassette containing a stimulable phosphor sheet 12 on which a radiation image is recorded is inserted. When the cassette is inserted into the insertion slot, the stimulable phosphor sheet 12 is automatically taken out from the cassette and conveyed toward the scanning surface 13 of the scanning optical system 10 by the conveyance system.

  The scanning optical system 10 is perpendicular to the paper surface (hereinafter referred to as the sub-scanning direction) S (hereinafter referred to as the sub-scanning direction) S with respect to the stimulable phosphor sheet 12 transported on the surface 13 to be scanned. , Written as the main scanning direction.) M scans the laser beam L. By the irradiation with the laser beam L, stimulated emission light is generated from the stimulable phosphor sheet 12.

  In the vicinity of the surface to be scanned 13, an incident surface of a transparent condensing guide 14 made of an acrylic plate or the like is disposed. A photoelectric converter 15 such as a photomultiplier is attached to the exit surface of the light collecting guide 14. The stimulated emission light enters the light collecting guide 14, is guided through the light collecting guide 14, enters the photoelectric converter 15, and is converted into an electric signal by the photoelectric converter 15. The electrical signal output from the photoelectric converter 15 is subjected to various signal processing by the control unit, whereby an image signal representing a radiation image recorded on the stimulable phosphor sheet 12 is output. The stimulable phosphor sheet 12 for which the reading of the radiation image has been completed is conveyed to the erasing unit to erase the radiation image, and then returned to the cassette again.

  2 and 3, the scanning optical system 10 has a configuration in which various optical elements including the light source unit 20 are housed in an optical box 21 that is integrally formed of synthetic resin. Although not shown, an upper lid is attached to the upper portion of the optical box 21, and the inside is sealed by the upper lid and incorporated in the radiation image reading apparatus 2.

  The light source unit 20 includes a fin 23 in which a laser light source 22 is incorporated and a housing 25 in which a collimator lens 24 is incorporated. The laser light source 22 is composed of a semiconductor laser or the like and emits a laser beam L. The collimator lens 24 converges the laser beam L into a parallel light beam.

  A beam splitter 26 is provided in front of the light source unit 20. The laser beam L passes through the beam splitter 26 and enters the light receiving sensor 27, while being reflected by the beam splitter 26. The light receiving sensor 27 detects the intensity of the transmitted light of the laser beam L and outputs the detection result to an APC (Auto Power Control) circuit 28. The operation of the laser light source 22 is controlled by the APC circuit 28 based on the detection result of the light receiving sensor 27, whereby the laser beam L is controlled to a constant light amount.

  The reflected light of the laser beam L reflected by the beam splitter 26 enters the imaging optical system 29. The imaging optical system 29 is provided with a diaphragm 30 and a cylindrical lens 31. The diaphragm 30 sets the light amount of the laser beam L. The cylindrical lens 31 condenses the laser beam L in the sub scanning direction S.

  The laser beam L transmitted through the imaging optical system 29 is incident on the deflecting / reflecting surface 33 of the polygon mirror 32 formed into a regular hexagonal shape. The deflection reflection surface 33 has a width of 3 mm, for example. The laser beam L that has reached the deflecting / reflecting surface 33 has a diameter of, for example, φ100 to φ150 μm. A rotating shaft of a motor 34 is connected to the polygon mirror 32 and is rotated at high speed in the arrow direction at a constant angular velocity. As a result, the laser beam L incident on the deflecting / reflecting surface 33 is deflected in the main scanning direction M and output.

  The laser beam L deflected by the polygon mirror 32 is transmitted through the spherical lens 35 and the toric lens 36 constituting the fθ lens, and thereby the scanning speed is made uniform and fθ correction is performed to correct distortion. The fθ-corrected laser beam L is reflected by the two cylindrical mirrors 37 and 38 toward the opening 39 provided on the side surface of the optical box 21 facing the scanned surface 13, and the scanned surface through the opening 39. 13 is irradiated. The diameter of the laser beam L on the scanned surface 13 is, for example, φ90 to φ100 μm.

  In FIG. 4, the inspection device 50 of the scanning optical system 10 of the present invention is for performing a comprehensive performance inspection before the scanning optical system 10 is shipped. The inspection apparatus 50 has a stage (not shown) on which the scanning optical system 10 before shipment is detachably set. The stage is provided with a large number of positioning members and locking members such as a clamp mechanism and a lock mechanism, and the scanning optical system 10 is fixed at a predetermined position.

  The scanned surface 13 is provided with three CCD sensors 51 a to 51 c (for example, 480 × 640 pixels, pixel size 7.4 μm) for imaging the laser beam L imaged on the scanned surface 13. Yes. The CCD sensors 51 a to 51 c are arranged at equal intervals in the main scanning direction M, and are arranged so that the imaging surface is parallel to the scanned surface 13.

  The CCD sensors 51a to 51c are placed on the microstages 52a to 52c. By operating the microstages 52a to 52c, the positions of the CCD sensors 51a to 51c can be finely adjusted. Although not shown, a mechanism that collectively slides these in the main scanning direction M is connected to the microstages 52a to 52c. The CCD sensors 51a to 51c are focused on the laser beam L imaged on the scanned surface 13 by these positioning mechanisms, and the center of the imaging surface coincides with the target irradiation position of the laser beam L. Positioned. Further, as shown in FIG. 5, the central CCD sensor 51b is attached to a moving stage 53 that moves them in the direction of an arrow parallel to the optical axis direction of the laser beam L via a microstage 52b.

  Returning to FIG. 4, the APC circuit 28, the motor 34, the CCD sensors 51 a to 51 c, and the moving stage 53 are connected to a personal computer (hereinafter referred to as PC) 54. At the time of inspection, the PC 54 transmits a drive control signal to the motor 34 so that the polygon mirror 32 is rotated at a constant angular velocity, and the APC is irradiated with the laser beam L for each of the six deflecting reflecting surfaces 33. A drive control signal is transmitted to the circuit 28. In addition, a drive control signal is transmitted to the CCD sensors 51a to 51c so as to capture images of the laser beams L reflected by the six deflecting reflecting surfaces 33 in synchronization with the rotation of the polygon mirror 32. Further, a drive control signal is transmitted to the moving stage 53 so that the CCD sensor 51b moves a specified amount, for example, 10 mm, in the optical axis direction of the laser beam L. Outputs of the CCD sensors 51a to 51c, that is, image data obtained by imaging the laser beam L are sequentially input to the PC 54.

  The PC 54 includes a monitor 55 and an operation input unit 56 including a keyboard and a mouse. In FIG. 6, the CPU 60 controls the overall operation of the PC 54. A display control unit 65 that controls the display of the communication I / F 62, the memory 63, the HDD 64, and the monitor 55 is connected to the CPU 60 through the bus 61, together with the operation input unit 56 described above.

  The communication I / F 62 mediates exchange of data with each unit connected to the APC circuit 28, the motor 34, and the PC 54. A program for the inspection apparatus 50 is installed in the HDD 64, and image data obtained by the CCD sensors 51a to 51c is recorded. The CPU 60 reads a program from the HDD 64 and develops it in the memory 63, and sequentially processes the read program. Further, the CPU 60 operates each unit of the PC 54 in accordance with an operation input signal input from the operation input unit 56.

  When the program for the inspection apparatus 50 is activated, an irradiation position calculation circuit 70, a parameter calculation circuit 71, and a determination circuit 72 are built in the CPU 60 as shown in FIG.

  Here, the diameter of the laser beam L on the deflecting / reflecting surface 33 is φ100 to φ150 μm and the diameter of the laser beam L on the scanned surface 13 is φ90 to φ100 μm, whereas the pixel size of the CCD sensors 51a to 51c is 7. Since it is 4 μm, as shown in FIG. 8A, the laser beam L (shown by oblique lines) is imaged across a plurality of pixels 73 of the CCD sensors 51a to 51c. At this time, the output of each pixel 73 in the vertical (Y) and horizontal (X) directions of the pixel array, that is, the distribution of luminance values, is taken as an example of (B) and (B) and (B) and (B) C) (hereinafter referred to as Y profile and X profile, respectively). That is, the luminance value of the pixel 73 that images the central portion of the laser beam L has a peak, and the luminance value decreases as the pixel 73 images the outer peripheral portion of the laser beam L.

  The irradiation position calculation circuit 70 detects the luminance value of each pixel 73 constituting the image data from the CCD sensors 51a to 51c, and creates X and Y profiles for each pixel array. Then, the XY coordinates of the pixel 73 having the peak luminance value are calculated as the irradiation position of the laser beam L.

  The irradiation position calculation circuit 70 performs the above-described processing for a plurality of continuous frames of image data for each deflecting reflection surface 33, averages the irradiation positions of the laser beams L calculated for each of the plurality of frames, The average value is adopted as the final irradiation position of the laser beam L. In the XY coordinates, the origin is the pixel 73 at the center of the imaging surface, which is the target irradiation position of the laser beam L.

  As shown in FIG. 9A, when the deflecting / reflecting surface 33 is tilted (tilted) with respect to the rotation axis R of the polygon mirror 32, the irradiation position of the laser beam L on the surface 13 to be scanned is It shifts in the scanning direction S, that is, the Y direction. For this reason, the parameter calculation circuit 71 obtains the difference between the maximum value and the minimum value of the Y coordinate of the irradiation position of the laser beam L from the six deflecting reflection surfaces 33 and calculates the difference between the surface tilt amounts (units) of the deflecting reflection surface 33. ; Μm).

  In addition, as shown in FIG. 5B, when the deflecting / reflecting surface 33 protrudes outside the normal dimension with respect to the rotation center O of the polygon mirror 32, or when it is retracted inside, the laser beam L is emitted. Since the time to reach the scanned surface 13 is earlier or later, the irradiation position of the laser beam L on the scanned surface 13 is shifted in the main scanning direction M, that is, the X direction. Therefore, the parameter calculation circuit 71 calculates the X coordinate of the irradiation position of the laser beam L from any one of the six deflecting reflection surfaces 33 and the X coordinate of the irradiation position of the laser beam L from the other surface. The jitter component is obtained from the deviation amount (unit:%).

Further, as shown in (C), when the angle (falling angle) between the scanned surface 13 and the laser beam L is deviated, the irradiation positions of the laser beam L before and after being moved by the moving stage 53 are as follows. , Shifted in the Y direction. Therefore, the parameter calculation circuit 71 considers the right-angled triangle on the right side, the amount of deviation ΔY in the Y direction of the irradiation position of the laser beam L before and after being moved by the moving stage 53, and the CCD sensor by the moving stage 53. From the moving amount of 51b of 10mm,
θ = tan ⁻¹ (ΔY / 10) (1)
This is used as the amount of shift in the falling angle (unit: deg).

  The determination circuit 72 compares each parameter of the surface tilt amount, jitter component, and fall angle shift amount calculated by the parameter calculation circuit 71 with the standard value. And when a parameter is smaller than a standard value, it determines with a test | inspection passing, and in the contrary, it determines with a rejection.

When the program for the inspection apparatus 50 is activated, a window 80 shown in FIG. 10 is displayed on the monitor 55. The window 80 includes an image frame 81, a data frame 82, and a user interface frame 83. In the image frame 81, images obtained by the CCD sensors 51a to 51c are displayed live. In the data frame 82, the XY coordinates of the irradiation position of the laser beam L and the diameter in the XY direction (for example, X / Y 2 including a pixel having a luminance value peak, 1 / e ² of the luminance value of the peak, or 13. (Width at 5%) average value information 84 and 85 and luminance value peak information 86 are displayed.

  In the user interface frame 83, a measurement start button 87 and the like are arranged. When the measurement start button 87 is selected, a drive control signal is transmitted from the PC 54 to each unit, whereby the laser light source 22 and the motor 34 are driven, and imaging by the CCD sensors 51a to 51c is started.

  After each parameter is calculated and determined, a window 90 shown in FIG. The window 90 includes a result display frame 91 and a data display frame 92. In the result display frame 91, for each parameter, the calculation result by the parameter calculation circuit 71 and the determination result by the determination circuit 72 (represented as “OK” if the test is passed, “NG” if not passed) are indicated. Will be listed.

  In the data display frame 92, the jitter component and the calculation result of the irradiation position calculation circuit 70 that is the basis for calculating the amount of surface tilt are displayed in a list for each deflection reflection surface 33. In addition, the calculation result of the irradiation position calculation circuit 70 at the normal position before being moved by the moving stage 53 and the calculation result at the position after 10 mm movement, which are the basis for calculating the amount of shift of the falling angle, are displayed. The

  Further, a window 100 shown in FIG. 12 is displayed on the monitor 55 by operating the operation input unit 56. The window 100 displays a list of standard values of each parameter, the number of times of irradiation position measurement, various driving conditions of the laser light source 22, and the shutter intervals of the CCD sensors 51a to 51c. These values can be set and changed by operating the operation input unit 56.

  Next, an inspection procedure by the inspection apparatus 50 configured as described above will be described. First, the scanning optical system 10 in which each component is fastened and fixed with screws or the like is set on the stage. Next, the inspection program is started, the window 80 is displayed on the monitor 55, and the measurement start button 87 is selected. Accordingly, a drive control signal is transmitted from the PC 54 to each unit, and the laser beam L is emitted from the laser light source 22 at a predetermined interval. At the same time, the motor 34 is driven to rotate the polygon mirror 32 at a constant angular velocity. In addition, imaging by the CCD sensors 51a to 51c is started.

  The laser beam L emitted from the laser light source 22 is converged into a parallel light beam by the collimator lens 24, passes through the beam splitter 26, enters the light receiving sensor 27, and is reflected by the beam splitter 26 to enter the imaging optical system 29. Incident. The laser beam L incident on the imaging optical system 29 has its light amount set by the diaphragm 30 and condensed by the cylindrical lens 31 in the sub-scanning direction.

  The laser beam L transmitted through the imaging optical system 29 is reflected by the deflecting / reflecting surface 33, transmitted through the spherical lens 35 and the toric lens 36, subjected to fθ correction, and then reflected by the cylindrical mirrors 37 and 38. Then, the surface to be scanned 13 is irradiated from the opening 39.

  The laser beam L irradiated to the scanning surface 13 is imaged by the CCD sensors 51a to 51c. The image data obtained by the CCD sensors 51a to 51c are sequentially input to the PC 54. In the PC 54, the luminance value of each pixel 73 constituting the image data from the CCD sensors 51a to 51c is detected by the irradiation position calculation circuit 70 for each deflecting / reflecting surface 33. Based on the detection result, X is determined for each pixel array. Y profile is created. Then, the XY coordinates of the pixel 73 having the peak luminance value are calculated for the continuous image data of a plurality of frames, and the calculated XY coordinates are averaged for each of the plurality of frames.

  After the above measurement is performed at the normal position, a drive control signal is transmitted from the PC 54 to the moving stage 53. As a result, the moving stage 53 is driven, and the CCD sensor 51b is moved 10 mm in the optical axis direction of the laser beam L. In this state, the above measurement is performed again. The calculation results of the irradiation position calculation circuit 70 obtained in this way are displayed in a list in the data display frame 92.

  When a series of measurements is completed, the parameter calculation circuit 71 obtains the difference between the maximum value and the minimum value of the Y coordinate of the irradiation position of the laser beam L from the deflection reflection surface 33 as the surface tilt amount of the deflection reflection surface 33. It is done. Further, the jitter component is obtained from the amount of deviation between the X coordinate of the irradiation position of the laser beam L from any one of the deflection reflection surfaces 33 and the X coordinate of the irradiation position of the laser beam L from the other surface. . Further, equation (1) is calculated, and the amount of deviation of the falling angle is obtained. The calculation results of the parameters thus obtained are displayed in a list in the result display frame 91.

  Then, in the determination circuit 72, the parameters of the surface tilt amount, the jitter component, and the fall angle shift amount calculated by the parameter calculation circuit 71, and the standard value set by operating the operation input unit 55, Are compared and pass / fail is determined. This determination result is displayed in a list in the result display frame 91 together with the calculation result by the parameter calculation circuit 71.

  When “NG” indicating failure of inspection is displayed in the result display frame 91, parts such as the polygon mirror 32 and the laser light source 22 are reassembled and the position is adjusted, and then the inspection is executed again, or the polygon mirror 32 Measures such as discarding the product as a defective product are taken. When “OK” is displayed in the result display frame 91, the scanning optical system 10 is removed from the stage, incorporated in the radiation image reading apparatus 2, and shipped as a product.

  As described above, the laser beam L is irradiated to each of the deflecting and reflecting surfaces 33, and the laser beams L are imaged by the CCD sensors 51a to 51c at the position of the surface to be scanned 13. From the image data obtained thereby, The irradiation position of the laser beam L on the scanning surface 13 is calculated, and the surface tilt amount, the jitter component, and the fall angle deviation amount of the deflecting / reflecting surface 33 are calculated from the calculated irradiation position, and pass / fail of these parameters is determined. Since the determination result is displayed on the monitor 55, the performance inspection of the scanning optical system 10 including the polygon mirror 32 can be comprehensively performed. Further, the adjustment can be completed before the scanning optical system 10 is incorporated into the radiation image reading apparatus 2, and the adjustment time can be greatly shortened.

  Further, since the irradiation position and diameter of the laser beam L for each of a plurality of frames are averaged and this average value is adopted as the final irradiation position and diameter of the laser beam L, measurement errors can be suppressed.

  In the above-described embodiment, an example in which the program for the inspection apparatus 50 is installed in the HDD 64 of the PC 54 and activated to thereby construct the irradiation position calculation circuit 70 in the CPU 60 has been described. However, the present invention is not limited to this, and a PC on which the irradiation position calculation circuit 70 or the like is mounted in the form of hardware such as a discrete circuit or FPGA may be used.

  In addition, the structure of the scanning optical system 10 of the said embodiment is an example, and does not specifically limit this invention. Further, the scanning optical system 10 incorporated in the radiation image reading apparatus 2 has been described as an example, but the present invention may be applied to a scanning optical system mounted on an image recording apparatus such as a laser printer, a copying machine, or a facsimile. .

It is the schematic which shows the scanning optical system periphery part of a radiographic image reading apparatus. It is the schematic which shows the structure of a scanning optical system. It is the schematic which shows the structure of a scanning optical system. It is the schematic which shows the structure of an inspection apparatus. It is the schematic which shows the structure of a movement stage. It is a block diagram which shows the structure of a personal computer. It is a block diagram which shows the structure of each circuit constructed | assembled by CPU. It is a figure which shows the concept for calculating the irradiation position of a laser beam, and a diameter, (A) is the positional relationship of the pixel of a CCD sensor and a laser beam, (B), (C) is a pixel with a height and width. The luminance value distribution of each pixel in the array is shown. It is a figure for demonstrating the outline | summary of each parameter typically, (A) shows the amount of surface inclination, (B) shows a jitter component, (C) shows the deviation | shift amount of a fall angle, respectively. It is explanatory drawing which shows the window displayed on a monitor. It is explanatory drawing which shows the window displayed on a monitor. It is explanatory drawing which shows the window displayed on a monitor.

Explanation of symbols

2 Radiation Image Reading Device 10 Scanning Optical System 13 Scanned Surface 21 Optical Box 22 Laser Light Source 28 APC Circuit 32 Polygon Mirror 33 Deflection Reflecting Surface 34 Motor 50 Inspection Devices 51a to 51c CCD Sensor 53 Moving Stage 54 Personal Computer (PC)
55 Monitor 56 Operation Input Unit 60 CPU
70 Irradiation Position Calculation Circuit 71 Parameter Calculation Circuit 72 Judgment Circuit 73 Pixel 91 Result Display Frame

Claims (9)

An optical element including a deflector having a plurality of deflection reflection surfaces for deflecting and reflecting a light beam from a light source toward a surface to be scanned is an apparatus for inspecting a scanning optical system housed in an optical box,
A light source control means for controlling the operation of the light source so that the light beam is irradiated to each of the plurality of deflection reflection surfaces with respect to the rotationally driven deflector;
An imaging means disposed on the scanned surface and imaging the light beam on the scanned surface;
Moving means for moving the imaging means in the optical axis direction of the light beam;
Analyzing image data obtained by the imaging means, and calculating an irradiation position calculating means for calculating an irradiation position of the light beam on the scanned surface;
Parameters for calculating the parameters of the surface tilt amounts and jitter components of the plurality of deflecting and reflecting surfaces, and the angle shift amount between the scanned surface and the optical axis of the light beam from the calculation result of the irradiation position calculating means A calculation means;
A determination means for comparing each calculated parameter with a standard value to determine pass / fail;
An inspection apparatus for a scanning optical system, comprising: a display unit that displays a determination result of the determination unit.   The said parameter calculation means calculates | requires the said surface tilt amount from the deviation | shift amount of the said irradiation position regarding the subscanning direction orthogonal to the main scanning direction where the said light beam is scanned. Inspection device for scanning optical system.   The scanning optical system inspection apparatus according to claim 1, wherein the parameter calculating unit obtains the jitter component from a deviation amount of the irradiation position in a main scanning direction in which the light beam is scanned.   The parameter calculation unit is configured to compare the light beam calculated from the image data obtained by the imaging unit before and after being moved by the moving unit with respect to a main scanning direction in which the light beam is scanned. 4. The scanning optical system according to claim 1, wherein the angular deviation amount is obtained from an irradiation position in the orthogonal sub-scanning direction and a movement amount of the imaging unit by the movement unit. 5. Inspection device.   5. The scanning optical system inspection apparatus according to claim 1, further comprising operation input means for setting and changing the standard value. The irradiation position calculation means detects the luminance value of each pixel of the imaging means constituting the image data,
Create a distribution of luminance values for each pixel for each vertical and horizontal pixel array,
6. The scanning optical system inspection apparatus according to claim 1, wherein a position of a pixel having a peak luminance value is calculated as an irradiation position of the light beam.   The irradiation position calculation means averages the irradiation positions of the light beam calculated from the image data for a plurality of frames, and finally outputs the averaged value. 2. An inspection apparatus for a scanning optical system according to 1.   The scanning optical system inspection apparatus according to claim 1, wherein a plurality of the imaging units are arranged at equal intervals along the scanning direction of the light beam. An optical element including a deflector having a plurality of deflection reflection surfaces for deflecting and reflecting a light beam from a light source toward a surface to be scanned is a method for inspecting a scanning optical system housed in an optical box,
Irradiating the rotationally driven deflector with the light beam for each of the plurality of deflection reflecting surfaces;
Imaging the light beam on the scanned surface with an imaging means disposed on the scanned surface;
Moving the imaging means in the optical axis direction of the light beam;
Analyzing the image data obtained by the imaging means, and calculating the irradiation position of the light beam on the scanned surface;
From the calculation result of the irradiation position, calculating each parameter of the surface tilt amount and jitter components of the plurality of deflecting reflection surfaces, and the amount of deviation of the angle between the scanned surface and the optical axis of the light beam;
Comparing each calculated parameter with a standard value to determine pass / fail;
A step of displaying the determination result, and a scanning optical system inspection method.

Images