JP4366254B2 - Scanning optical system inspection apparatus and method - Google Patents

Description

  The present invention obtains beam light flux data at various locations of a scanning optical system for an image forming apparatus such as an electrophotographic writing unit, a copying machine having an image forming unit composed of a photoreceptor, a printer product, and the like. The present invention also relates to a scanning optical system inspection apparatus and method for inspecting a scanning optical system from the obtained optical characteristics.

2. Description of the Related Art Conventionally, there is a scanning optical system inspection apparatus that inspects optical characteristics of an apparatus that forms an image using a beam light beam emitted from a scanning optical system (writing unit) including a light source.
In general, the beam flux emitted from the writing unit in such a scanning optical system inspection device has a continuous dot array of dark current light emission and illumination beam by bias current injection for improving the response of the light source.
When inspecting and measuring the optical characteristics by acquiring such a beam, a detailed inspection and measurement is performed on the beam entering the field of view of the inspection / measurement system, and the moving mechanism sequentially moves in the main scanning direction etc. The entire area will be inspected.

  As such an apparatus, the device disclosed in Patent Document 1 includes a beam diameter sensor and a plurality of beam height detection sensors, and detects a beam scanning line curve with the beam height detection sensor in advance, and an objective lens at that position. The beam diameter sensor composed of the lens barrel and the light intensity sensor is moved to evaluate the scanning beam.

In the case of Patent Document 2 previously filed by the present applicant, a two-dimensional area light receiving sensor that can move in the same direction as the scanning direction of the scanning beam is provided, and the two-dimensional area light receiving sensor is arranged in the scanning direction of the scanning beam. The scanning beam is detected by the light receiving sensor while being moved, and the scanning beam received by the light receiving sensor is stored in the data storage unit in association with the position information, and then the scanning beam data stored in the data storage unit is used. The light quantity distribution of the scanning beam scanned in the X direction is analyzed.
Japanese Patent No. 3421976 JP 2002-86795 A

However, in the conventional scanning optical system inspection apparatus described above, the beam light flux continuously exists in the vicinity of the beam light flux other than the beam light beam to be inspected. Moreover, the angles of these continuously existing beams vary depending on the position in the main scanning direction.
For this reason, the beam beam propagating out of the field of view is scattered by the lens frame of the inspection optical system, and the scattered light enters the field of view and becomes a noise superimposed on the beam beam of the inspection object in a wide range, There is a possibility that an effective inspection target area for acquiring the scanning beam luminous flux cannot be secured. This problem may cause inability to inspect and measure.

  Moreover, the thing of the patent document 1 mentioned above utilizes the objective lens for the beam diameter sensor, and a test object is the scanning beam light beam in arbitrary positions. Since the beam height sensor is provided, there is a possibility that the beam height sensor cannot be used effectively unless the beam light flux is to be inspected in the state of blinking continuously or continuously lighting. However, the countermeasure against the scattered light in the frame of the objective lens is not taken into consideration for the beam beam having an angle corresponding to the predetermined main scanning position.

  Also, in the above-mentioned Patent Document 2, dots and bias light of the scanning beam are continuously present, but it is considered that the beam beam outside the inspection target region is scattered by the lens frame of the inspection optical system. It was not.

  The present invention has been made in view of such circumstances, and in scanning optical system inspection, scanning beam light flux is obtained by preventing scattering of scanning beam light flux in the lens frame of the inspection optical system. It is an object of the present invention to provide a scanning optical system inspection apparatus and method capable of securing an effective inspection target region for acquiring and inspecting and acquiring only a beam beam to be inspected.

In order to achieve such an object, a scanning optical system inspection apparatus according to a first aspect of the present invention inspects optical characteristics of an apparatus that forms an image using a beam of light emitted from a scanning optical system having a light source. A scanning optical system inspection apparatus for receiving a light beam emitted from the scanning optical system, an imaging means for forming an image of the light beam on a light receiving surface of the light receiving means, and a direction perpendicular to the beam light beam scanning direction. A shielding means for shielding the noise light generated from the beam light beam outside the inspection target area by the scanning optical system inspection device from being re-imaged on the light receiving surface, and adjusting the installation state of the shielding means And adjusting means.

  According to the above technical means, it is possible to suppress noise light generated by reflection / scattering of the bias light existing in the scanning direction of the light beam itself or the adjacent lit dot light by the frame of the imaging means.

Opening of the shielding means noted above is preferably provided on the beam incident side of the imaging means.

The adjusting means described above is preferably a moving mechanism that adjusts the position of the shielding means by moving the shielding means perpendicular to the optical axis of the imaging means.
Further, the adjusting means described above may be a rotating mechanism that adjusts the angle of the shielding means by rotating the shielding means.

In order to receive the light beam emitted from the scanning optical system at a plurality of positions, the light receiving means and / or the imaging means is moved in the scanning direction, and the imaging means is moved at the position moved by the moving means. It is preferable that the position of the shielding means is adjusted by the moving mechanism according to the angle of the beam beam incident on the light beam.
According to the above technical means, the generation of noise light can be suppressed regardless of the position in the scanning direction for receiving the beam and the angle change of the beam.

In addition, in order to receive the light beam emitted from the scanning optical system at a plurality of positions, a moving means for moving the light receiving means and / or the imaging means in the scanning direction is provided, and the moving light is connected at the position moved by the moving means. The angle of the shielding means may be adjusted by a rotation mechanism according to the angle of the beam of light incident on the image means.
According to the above technical means, the generation of noise light can be suppressed regardless of the position in the scanning direction for receiving the beam and the angle change of the beam.

First moving means for moving the light receiving means and / or the imaging means in the scanning direction to receive the light beam emitted from the scanning optical system at a plurality of positions, and the light receiving means and / or the imaging means described above Is moved relative to the scanning optical system in the optical axis direction of the imaging means, and enters the imaging means at a position moved by the moving means and / or the second moving means. It is preferable that the position of the shielding means is adjusted by the moving mechanism according to the angle of the beam.
According to the above technical means, the generation of noise light can be suppressed regardless of the position in the scanning direction for receiving the beam and the angle change of the beam.

First moving means for moving the light receiving means and / or the imaging means in the scanning direction to receive the light beam emitted from the scanning optical system at a plurality of positions, and the light receiving means and / or the imaging means described above Is moved relative to the scanning optical system in the optical axis direction of the imaging means, and enters the imaging means at a position moved by the moving means and / or the second moving means. It is preferable that the angle of the shielding means is adjusted by the rotation mechanism according to the angle of the beam of the light beam.
According to the above technical means, the generation of noise light can be suppressed regardless of the position in the scanning direction for receiving the beam and the angle change of the beam.

  Further, in the scanning optical system inspection apparatus according to each aspect described above, the scanning optical system modulates the beam beam emitted from the light source, scans the modulated beam beam, and forms the reflected image by reflecting the beam beam. It is preferable to be provided in a device having a system for generating an image by forming an image of a beam flux scanned by an element on a photosensitive drum or the like.

A scanning optical system inspection method according to another aspect of the present invention is a scanning optical system inspection method for inspecting optical characteristics of an apparatus that forms an image using a beam of light emitted from a scanning optical system including a light source. A light receiving step of continuously lighting the light source; a light receiving means having a light receiving surface for forming an image of the beam light beam emitted from the scanning optical system ; A separation step for separating the data from the scattered light data scattered by the beam light beam, and a shielding means for shielding noise light generated from the beam light beam outside the inspection target region by the scanning optical system inspection method so as not to re-image on the light receiving surface And an adjusting step for adjusting the installation state until the scattering is eliminated.
According to the above technical means, the beam can be received without receiving noise light due to scattering.

As described above, according to the present invention, it is possible to prevent the scanning beam from being scattered by the lens frame of the inspection optical system even in the inspection of the scanning optical system.
For this reason, it is possible to secure an effective inspection target region for acquiring the scanning beam light beam, to acquire and inspect only the beam light beam to be inspected, and to perform high-accuracy and high-efficiency inspection.

Next, an embodiment to which a scanning optical system inspection apparatus and method according to the present invention are applied will be described in detail with reference to the drawings.
The present invention relates to an apparatus and a method that can inspect noise generated by scattering of beam beams continuously existing outside a detection target region peculiar to a scanning beam by an inspection optical system without overlapping valid data.
First, an outline of the present invention will be described, and then details of the present embodiment will be described.

  A writing unit having a scanning optical system mounted on an electrophotographic image product shapes a beam beam emitted from a light source such as an LD (laser diode) by a collimator lens and modulates it into a scanning beam by a rotating polyhedral mirror or the like. The beam flux modulated into the scanning beam passes through an optical element such as an fθ lens, a cylindrical lens, or a mirror, is processed into a desired beam diameter and beam profile, and forms an image as a dot row at a desired position on the photosensitive surface. .

  An electrostatic latent image is formed from the light quantity distribution state of the beam light beam formed on the photosensitive surface, and then an image is formed by an image forming process. At that time, if the beam does not form an image at the desired beam position, the image quality is deteriorated due to the dot position shift. There is a possibility that the image quality is deteriorated due to the relative displacement of the dots.

  Here, dot misregistration is caused by misalignment in the scanning direction due to temporal errors in light source control, scanning line bending in which the scanning line of the scanning beam is bent in a direction perpendicular to the scanning direction, and scanning line tilt. This is the misalignment. Also, if the desired beam diameter cannot be obtained, the amount of light will be dispersed and sufficient amount of light to form a latent image will not be obtained. Even if the amount of light is obtained, the area on which the toner etc. is placed will be enlarged and the image will be sharp. There is a risk that problems such as lowering may occur.

The optical element used in the writing unit is usually long in the main scanning direction and short in the sub scanning direction. Optical characteristics such as the beam diameter and beam position set in the main and sub scanning directions over the wide main scanning direction must satisfy the specifications. Therefore, it is necessary to verify the quality of the beam in the entire main scanning direction. In addition, the photosensitive member must be positioned within the focal depth of the writing unit, and it is necessary to verify the characteristics of the beam in the optical axis direction as well as in the entire main scanning direction.
As the resolution of image products increases, the beam flux becomes smaller and it is necessary to inspect and measure the beam with a higher-definition detection system.

In the light source control of the scanning optical system, the higher the resolution of the image product, the higher the frequency of the control pulse, and the responsiveness of the light source is also required. Control pulse shapes and output light intensity waveforms have also been manipulated with high accuracy. In order to improve the responsiveness of the light source, an LD (laser diode) light source or the like always injects a bias current and relatively lowers the lighting threshold. In that case, it is always in a naturally induced light emission state. Therefore, strictly speaking, it can be said that the scanning beam is continuous in the main scanning region.
In addition, with the progress of processing technology, the optical element shape has a free-form surface shape, and the propagation angle of the beam at each position in the main scanning direction is arbitrarily set.

Here, the verification of the beam flux of the scanning optical system is for a stationary beam with the rotating polygon mirror fixed.
<1> A method of measuring a light quantity distribution by scanning a beam with a slit and detecting the light quantity passing through the slit in time series <2> A method of detecting a beam profile two-dimensionally by forming an image on a two-dimensional area sensor and so on.

On the other hand, with the rotating polygon mirror rotated,
<3> A method of detecting a light amount distribution state by scanning a light source in a constantly lit state, traversing the slit, and detecting the amount of light passing through the slit in time series as in the method <1> above. The main method is to detect the light distribution state of the scanning flashing beam with a two-dimensional area sensor while keeping the light source in a flashing state and synchronizing with the scanning cycle. In addition, there are a method using a line sensor, a method in which a slit is provided with an angle, and a beam diameter in the main / sub scanning direction is supported.

  In general, in the slit scanning method according to the above <1> and <3>, the light amount of the beam passing through the slit is an integrated light amount in the slit direction cut by the slit, so that it has an ideal shape such as a Gaussian beam. Although it is possible to detect the beam diameter appropriately, it can be said that in practice it is difficult to obtain a beam having an ideal shape by diffraction or beam rotation, which is not suitable. In addition, since the amount of light to be cut by the slit is detected, it is difficult to detect even the state of the beam of light in the writing unit such as interference between the head portion and the optical element.

  As a device, a mechanism for moving the detection optical system in the optical axis direction and a mechanism for moving in the main scanning direction and the sub-scanning direction are provided to detect the defocus amount of the beam imaged on the photosensitive surface of the writing unit. A configuration, a configuration corresponding to detection in the entire region in the main scanning direction, and a configuration following the beam position in the sub-scanning direction are generally used.

  In order to improve the response of the light source, the beam luminous flux emitted from the writing unit has dark current light emission by injection of bias current and dot rows by lighting beams continuously. The angles of these continuously existing beams vary depending on the position in the main scanning direction. When inspecting and measuring the optical characteristics by acquiring the beam flux, detailed inspection and measurement is performed on the beam entering the field of view of the inspection and measurement system, and the entire area is moved sequentially in the main scanning direction by the moving mechanism. Can be inspected.

  However, the beam flux continuously exists in the vicinity of the beam flux other than the beam flux to be inspected. In addition, the propagation angle varies depending on the position. For this reason, the beam beam propagating out of the field of view is scattered by the lens frame of the inspection optical system, enters the field of view, and becomes a noise superimposed on the beam beam beam to be inspected over a wide range. There was a case. Further, the actual scanning beam luminous flux is limited to the same height at which the lens frame is irradiated due to a scanning line bending of one scanning optical system to be inspected or a solid difference in scanning line bending between a plurality of scanning optical systems. Since it is not a thing, the conditions which generate | occur | produce all the noise light scattered by a lens frame are not necessarily the same.

  Therefore, in the present invention, in the inspection of the scanning optical system, the scanning beam light beam is not scattered by the lens frame of the inspection optical system, and an effective inspection target area for acquiring the scanning beam light beam is ensured. It is an object of the present invention to provide a scanning optical system inspection apparatus and method capable of acquiring and inspecting only the light beam of the beam.

Next, details of the scanning optical system inspection apparatus as an embodiment of the present invention will be described with reference to the drawings.
For example, as shown in FIG. 1, a beam flux emitted from an LD (laser diode) unit (2) is reflected by a rotating polygon mirror (1), passes through an fθ lens (3), and forms an image plane (4). In the scanning optical system (5) to be scanned and imaged in FIG. 2, when the LD control pulse is inputted as an injection current to the LD unit (2) and the lighting state of the LD is controlled, the image plane (4) is shown in FIG. A dot (6) row as shown is formed.

  In order to increase the responsiveness of the LD as the control becomes higher in frequency, a bias current is input, and the difference from the standby state where the LD emits spontaneously induced light to the current value at which the laser emits is reduced. At that time, as shown in FIG. 3, bias light (7) exists as a background of the dot row.

  The relationship between the amount of bias light and the threshold to which the photosensitive member is sensitive is as shown in FIG. By measuring the beam diameter, beam position, etc. of these dot rows, it is possible to verify the quality of the scanning optical system and the scanning lens, polygon mirror, and the like constituting the scanning optical system. In recent years, with the increase in image quality of image products, the beam size has been reduced, and it has been necessary to improve the resolution of the inspection optical system in order to inspect and measure the beam beam with high accuracy.

As shown in FIG. 5, the scanning optical system is inspected and measured by an objective lens (imaging means) (8) in which the scanning beam emitted from the scanning optical system (5a) is focused on the imaging plane (4a). And is received by a two-dimensional CCD area sensor (light receiving means) (9).
Normally, as shown in FIG. 6, since the objective lens exhibits its lens performance effectively, the objective lens frame (10) itself becomes an aperture and defines its effective diameter.

  The aperture (NA) is designed uniquely for the lens, and incident light flux that does not meet the specifications does not form an image on the light receiving surface (16) of the two-dimensional CCD area sensor (9) by the aperture stop (12) inside the lens. It has become. In addition, the aperture stop serves to reduce the amount of incident light that is too bright. When inputting a general image, an image that follows all optical paths as diffused light and satisfies the lens specifications is re-imaged on the light-receiving surface (16), so the brightness is reduced by blocking part of it with an aperture stop. In addition, it also has a function of removing light affected by the aberration of the lens with respect to the incident light passing through the periphery of the lens.

  However, the scanning beam flux emitted from the scanning optical system re-images on the light receiving surface as each beam flux follows the respective optical path, and thus blocks a part of the light reaching the diffused light from the imaging multi-object. Unlike the above-mentioned function, it serves to limit the beam light flux to be inspected. A beam beam (14) propagating at an angle satisfying NA through the entrance pupil (15) with respect to the light receiving surface (16) in FIG. 6 is re-imaged on the light receiving surface (16).

The lens frame has a structure in which the lens is fixed, and has a thickness and an angle with respect to the incident light. As shown in FIG. 7, the beam flux (14d) that is originally outside the entrance pupil (15a) and outside the inspection target area is generated. Then, it is reflected and scattered by the lens frame (10a), becomes noise light (17), enters the inspection object region, is received by the light receiving surface (16a), and is superimposed on the inspection object beam as shown in FIG. There is a possibility that the inspection and measurement may be impossible due to the noise light (17a).
It has been confirmed that this noise light is caused by dot scattering or bias light scattering. Since the noise light is generated by the scanning beam light beam emitted from the scanning optical system and outside the inspection target region, it is peculiar to the scanning optical system and is generated only in the scanning direction.
Real images of such received light beams of the scanning beam and noise light are illustrated in FIGS.

Therefore, as shown in FIG. 12, in order not to re-image noise light existing only in the scanning direction peculiar to the scanning optical system on the light receiving surface, an inspection target region of the scanning beam (14e) is defined on the incident side of the objective lens. A light shielding plate (shielding means) (18) is provided.
As shown in FIG. 13, by installing the light shielding plate (18a), the scanning beam (14f) that propagates at a predetermined angle and becomes noise light due to reflection and scattering at the lens frame (10b) is blocked. However, as shown in FIG. 14, for example, scattered light (17b, 17c) is generated by incidence from the front, and noise light (17d, 17e) shown in FIG. ) Was received in a superimposed manner.

Such a phenomenon is caused by a propagation angle for each scanning position within one individual of the scanning optical system, and at the same time, a variation in propagation angle between individuals due to an assembly error of the optical elements of the scanning optical system. Therefore, it is necessary to adjust the position of the light shielding plate corresponding to the propagation angle for each scanning position and individual differences.
As an example, as shown in FIG. 16, by providing a moving mechanism (19) for translating the light shielding plate (18c) perpendicularly to the optical axis of the objective lens, it is possible to remove reflection and scattering from the lens frame. And
Here, although there is a concern about the scattering and diffraction of the beam beam by the light shielding plate (18c), in this embodiment, by adjusting the scattered light and the diffracted light so as not to form an image on the light receiving surface by combining with the objective lens, Can be resolved.

In addition, as shown in FIG. 17, there is an example in which a moving mechanism (20) for moving the light shielding plate (18d) in the optical axis direction of the objective lens is added to give the flexibility of the NA adjustment of the inspection optical system.
Further, the translation angle of the scanning optical system may not correspond to the propagation angle of the scanning beam light beam (14i) that differs depending on the position in the scanning direction of the scanning optical system only by the translational movement of the light shielding plate (18d) in FIG. By adding the rotation mechanism (21) for rotating the light shielding plate (18e), the effective diameter of the lens can be utilized to the maximum, corresponding to the propagation angle of the scanning beam light flux that differs for each position in the scanning direction of the scanning optical system. It becomes possible. By combining these moving mechanisms, it is possible to change only the angle without changing the opening width of the light shielding plate.

As a method for adjusting the light shielding plate, a method of extracting a component having an angle and a scanning direction (horizontal direction in the drawing) of the scanning beam from the received light image by using a Hough transform or the like shown in FIGS.
In the configuration operation in which the shielding plate is adjusted until the scattered light disappears, as shown in FIG. 19, the LD is continuously turned on to obtain a re-imaged image (22) of the scanning beam. Since it is continuously lit, the noise image (17f) can inevitably be acquired, unlike the case where the dot when the dot is lit is reflected and scattered by the lens frame and becomes a noise image with a relatively low light amount.

An image (22a) of the scanning beam light flux at the time of continuous lighting when the light shielding plate is set such that the noise image (17f) as shown in FIG. 20 can be confirmed visually is obtained, and the difference between the images is acquired. By performing the above, an image in which the noise light image (17g) is emphasized as shown in FIG. 21 is obtained. By performing the Hough transform in FIG. 20 and extracting an image having an angle different from that in the horizontal direction, the presence or absence of noise light can be confirmed.
The movement mechanism can be adjusted until the noise light disappears, and the posture of the light shielding plate can be set, and the adjustment can also be automated by setting the separation condition from the infinite loop at the time of adjustment.

As an advantage of applying the scanning beam luminous flux at the time of continuous lighting, there is no positional deviation in the scanning direction at the time of dot lighting, and for the positional deviation correction in the direction perpendicular to the scanning direction between the images for which the difference is taken, The positional deviation in the height direction is derived by binarization and centroid detection. The scanning beam flux during continuous lighting is very large because the beams are continuously superimposed, and noise light etc. can be ignored by binarization, so it can detect displacement in the direction perpendicular to the scanning direction. Becomes easy.
The position of the light shielding plate can be adjusted by installing a motor-driven translation stage or rotation stage.

  As described above, this embodiment, as a first example, includes a light source and an element that modulates a beam beam emitted from the light source, scans the modulated beam beam, and reflects the beam beam to form a reflection image. When inspecting the optical characteristics of a scanning optical system mounted on an image product that has a system that generates an image by forming an image of the scanned beam on a photosensitive drum, etc., the beam emitted from the scanning optical system is received. A light receiving means for performing image formation on the light receiving means, a data processing means for processing received light received by the light receiving means, and a beam light beam scanning direction perpendicular to the beam light flux incident side of the imaging means. Biasing light that exists in the scanning direction of the beam of light itself or an adjacent lit dot that has shielding means having a long opening in the direction and means for adjusting the position of the shielding means There so as to suppress the noise light generated by reflection and scattering at the frame of the imaging means.

  As described above, according to the present embodiment, in the inspection verification of the scanning optical system constituting the writing unit of the image product, the scanning beam has a different propagation angle and relative position with respect to the inspection optical system at each position in the scanning direction. By installing the shielding means at an arbitrary position, the beam light beam outside the inspection target area that continuously exists in the main scanning direction peculiar to the scanning beam is scattered by the lens frame of the inspection optical system and becomes noise light in the inspection area. It is possible to provide a scanning optical system inspection apparatus that can prevent the spread and acquire and inspect only the beam light beam to be inspected.

  As described above, this embodiment is a second example in which a light source and a beam beam emitted from the light source are modulated, the modulated beam beam is scanned, and the beam beam is reflected and imaged. Beam light beam emitted from the scanning optical system when inspecting the optical characteristics of the scanning optical system mounted on an image product having a system for generating an image by forming a beam light beam scanned by the element on a photosensitive drum or the like A light receiving means for receiving light, an image forming means for forming an image of the light beam on the light receiving means, a data processing means for processing light reception data received by the light receiving means, and a beam light beam scanning direction on the beam light beam incident side of the image forming means. Bias light existing in the scanning direction of the beam of light itself or an adjacent lighting state having shielding means having a long opening in a direction perpendicular to the light and means for adjusting the angle of the shielding means May be suppressing noise light dots light is generated by reflected and scattered by the frame of the imaging means.

  As described above, according to the second example of the present embodiment, in the inspection verification of the scanning optical system constituting the writing unit of the image product, the scanning beam has the propagation angle and the inspection optical system at each position in the main scanning direction. Since the relative position is different from that of the scanning beam, the light beam outside the region to be inspected that exists continuously in the main scanning direction peculiar to the scanning beam is scattered by the lens frame of the inspection optical system by installing the shielding means at an arbitrary angle. Thus, it is possible to provide a scanning optical system inspection apparatus that prevents the noise light from spreading to the inspection region and that can acquire and inspect only the beam beam to be inspected.

  In addition, as a third example, this embodiment scans the light receiving means and / or the imaging means in order to receive the light beam emitted and scanned from the scanning optical system at a plurality of positions in the first example. A moving means that moves in the direction, and the position of the shielding means is adjusted by the angle of the beam light beam incident on the imaging means at the position moved by the moving means, and the position in the scanning direction for receiving the light beam, the light beam The generation of noise light may be suppressed regardless of the angle change.

  As described above, according to the third embodiment, in the scanning optical system inspection apparatus as the first embodiment described above, the propagation angle of the beam light beam peculiar to the scanning optical system is different at each position in the main scanning direction. Correspondingly, the position of the shielding means can be adjusted to prevent the beam beam outside the inspection area from being scattered by the lens frame and spreading to the inspection area as noise light, and only the inspection target beam can be acquired and inspected. A scanning optical system inspection apparatus can be provided.

  Further, in this embodiment, as a fourth example, the light receiving means and / or the imaging means are scanned in order to receive the light beam emitted and scanned from the scanning optical system at a plurality of positions in the second example described above. A moving means that moves in the direction, and adjusts the angle of the shielding means according to the angle of the beam light beam incident on the imaging means at the position moved by the moving means, the position in the scanning direction for receiving the light beam, and the light beam The generation of noise light may be suppressed regardless of the angle change.

  As described above, according to the fourth embodiment, in the scanning optical system inspection apparatus as the second embodiment described above, the propagation angle of the beam light beam peculiar to the scanning optical system is different at each position in the main scanning direction. Correspondingly, the angle of the shielding means can be adjusted to prevent the beam beam outside the inspection area from being scattered by the lens frame and spreading to the inspection area as noise light, and only the inspection target beam can be acquired and inspected. A scanning optical system inspection apparatus can be provided.

As the third and fourth embodiments described above, for example, in the configuration shown in FIG. 22, the objective lens (8b) and the two-dimensional CCD (9a) are placed on the base (23), and the objective is placed on the base (23). A translational and / or rotary stage useful for adjusting the position of the light shielding plate and the light shielding plate (not shown) is mounted on the beam beam incident side of the lens (8b).
The base (23) is fixed to the moving stage (24) so that the scanning beam can be obtained at all positions in the scanning direction of the scanning optical system. The moving stage (24) requires accuracy so as not to cause an error in the position information of the scanning beam. A linear stage can be considered.

  In addition, the present embodiment is a fifth example, in which the light receiving means and / or the imaging for receiving the light beams emitted and scanned from the scanning optical system at a plurality of positions in the first and third examples described above. A first moving means for moving the means in the scanning direction; a second moving means for moving the light receiving means and / or the imaging means relative to the scanning optical system in the optical axis direction of the imaging means; And / or means for adjusting the position of the shielding means according to the angle of the beam light beam incident on the imaging means at the position moved by the second moving means, and the position in the scanning direction for receiving the beam light beam, You may make it suppress generation | occurrence | production of noise light irrespective of an angle change.

In general, when acquiring the optical characteristics of the scanning optical system also in the depth direction data of the scanning optical system, the inspection optical system and the scanning optical system must move relatively in the optical axis direction, and the propagation angle of the beam beam As a result, the beam beam and the inspection optical system relatively move in the main scanning direction, and the beam beam incident on the inspection optical system is replaced with a beam in another region.
Therefore, according to the fifth embodiment described above, in the scanning optical system inspection apparatus as the first and third embodiments described above, the shielding means is newly adjusted in accordance with the angle and position of the beam light beam to be inspected. By adjusting the position, it is possible to prevent the beam beam outside the inspection target area from being scattered by the lens frame and spreading to the inspection area as noise light, and to acquire and inspect only the beam light beam to be inspected. An inspection device can be provided.

  Further, in the present embodiment, as a sixth example, with respect to the second and fourth examples described above, a light receiving means and / or an image forming unit for receiving light beams emitted and scanned from the scanning optical system at a plurality of positions. A first moving means for moving the means in the scanning direction; a second moving means for moving the light receiving means and / or the imaging means relative to the scanning optical system in the optical axis direction of the imaging means; And / or a means for adjusting the angle of the shielding means by the angle of the beam light beam incident on the imaging means at the position moved by the second moving means, and the position in the scanning direction for receiving the beam light beam, You may make it suppress generation | occurrence | production of the said noise light irrespective of an angle change.

In general, when acquiring the optical characteristics of the scanning optical system also in the depth direction data of the scanning optical system, the inspection optical system and the scanning optical system must move relatively in the optical axis direction, and the propagation angle of the beam beam As a result, the beam beam and the inspection optical system relatively move in the main scanning direction, and the beam beam incident on the inspection optical system is replaced with a beam in another region.
Therefore, according to the above-described sixth embodiment, in the scanning optical system inspection apparatus as the above-described second and fourth embodiments, the shielding means is newly adjusted in accordance with the angle and position of the beam light beam to be inspected. By adjusting the angle, a scanning optical system that prevents the beam beam outside the inspection target region from being scattered by the lens frame and spreading to the inspection region as noise light, enabling acquisition and inspection of only the inspection target beam beam. An inspection device can be provided.

As the fifth and sixth embodiments described above, for example, as shown in FIG. 23, the scanning optical system (5c) is installed on a stage (25) that moves in the optical axis direction (horizontal direction in the figure), and an objective lens. It is possible to move relative to the inspection optical system comprising (8c) and the two-dimensional CCD area sensor (23a). The moving stage (25) can be moved by motor driving or the like.
Thereby, the optical characteristics in the depth direction such as the imaging characteristics of the optical element such as the fθ lens (3c) of the scanning optical system can be verified.

When propagating at an angle with respect to the optical axis of the scanning beam image objective lens (8c), the scanning optical system and the inspection optical system move relative to each other in the optical axis direction, so that the scanning to be inspected is performed. The beam flux is shifted in the scanning direction. For this reason, the propagation angle of the beam light beam to be newly inspected at the position after the movement is different from the propagation angle of the scanning beam light beam that was the inspection object before the movement. Therefore, the posture of the light shielding plate is adjusted before and after the movement. .
The mechanism for adjusting the light shielding plate may be as described above. Similar to the configuration operations in the third and fourth embodiments described above, a light shielding plate (not shown) and a translation stage for adjusting the posture of the light shielding plate and / or a rotation stage on the base (23a) and on the incident side of the objective lens (8c). Have

  Further, this embodiment is a seventh example in which a light source and a beam scanned by an element that modulates the beam beam emitted from the light source, scans the modulated beam beam, and reflects the beam beam to form a reflection image or the like. A light receiving means for receiving the light beam emitted from the scanning optical system when inspecting the optical characteristics of the scanning optical system mounted on an image product having a system for generating an image by forming an image on the photosensitive drum. And an image forming means for forming an image of the light beam on the light receiving means, and a first means for moving the light receiving means and / or the image forming means in the scanning direction in order to receive the light beam emitted and scanned from the scanning optical system at a plurality of positions. Moving means, a second moving means for moving the light receiving means and / or the imaging means in a direction perpendicular to the plane including the scanning direction and the beam light flux propagation direction, and the beam light flux obtained by the light receiving means. It has data processing means for processing the light quantity data, and the light receiving means and / or the image forming means are moved by the second moving means until the light receiving data of the beam and the light receiving data of the scattered light from the frame of the image forming means are separated. You may make it do.

  As described above, according to the seventh embodiment, the inspection optical system and the scanning optical system are configured so that the direction in which the beam light beam outside the inspection target region is scattered does not overlap the beam light beam to be inspected from the shape of the lens frame. Scanning optics that adjusts the relative height of the beam to prevent the beam beam outside the inspection target area from being scattered by the lens frame and spreading as noise light to the inspection area, and to acquire and inspect only the beam light beam to be inspected A system inspection apparatus can be provided.

  As the seventh embodiment, for example, as shown in FIG. 24, the frame of the objective lens has a circular opening, and the frame and the scanning beam luminous flux depend on where the scanning beam luminous flux crosses in the height direction of the objective lens. The angle of the intersecting edges varies. Therefore, by adjusting the relative height of the scanning beam and the objective lens, it is possible to control the relative position between the received image of the scanning beam and the received image of the noise light reflected and scattered by the frame.

  As a configuration for realizing such a seventh embodiment, as shown in FIG. 25 when the scanning optical system and the inspection optical system are viewed from the side, the scanning optical system (5d) is replaced with an objective lens (8e) and a two-dimensional CCD area sensor ( A height moving stage (26) for adjusting the relative height to the inspection optical system consisting of 9c) is installed.

  When the height is moved, the relative position between the light receiving image of the scanning beam and the light receiving image of the noise light in FIG. 8 is displaced to a relative position as shown in FIG. Naturally, since the incident height of the scanning beam beam on the objective lens changes, the position of the received image of the scanning beam beam also changes. The determination of the completion of the relative position adjustment between the scanning beam beam and the noise light can be realized by a method using the scanning beam beam during continuous lighting, as in the previous embodiment.

  Although not shown in FIGS. 24 to 26, the relative movement amount of the scanning optical system and the inspection optical system can be calculated by adding a height measuring device that detects the movement amount in the height direction. It is possible to feed back to the data related to the height of the measurement result of the luminous flux.

  Further, this embodiment is an eighth example in which the light receiving means and / or the imaging means are moved relative to the scanning optical system in the optical axis direction of the imaging means in the seventh example. And a data processing means for processing the light quantity data of the beam light beam acquired by the light receiving means, until the light receiving data of the beam light flux and the light receiving data of the scattered light from the frame of the imaging means are separated. The light receiving means and / or the imaging means may be moved by the second moving means.

  Thus, according to the eighth embodiment, in the scanning optical system inspection apparatus as the seventh embodiment described above, the scanning optical system and the inspection optical system move relatively in the optical axis direction, and the beam flux is When propagating at an angle perpendicular to the main scanning direction, the relative height of the inspection optical system and the beam beam fluctuates, and the position where the beam beam outside the inspection object area hits the lens frame fluctuates. The relative height between the inspection optical system and the scanning optical system is adjusted again so that the direction in which the beam light beam is scattered does not overlap with the beam light beam to be inspected from the shape of the lens frame. It is possible to provide a scanning optical system inspection apparatus capable of preventing only the beam beam to be inspected from being acquired and inspected by preventing the light from being scattered by the lens frame and spreading as noise light to the inspection area.

  As the eighth embodiment described above, for example, as shown in FIG. 27 in which the line-of-sight direction is the same as that in FIG. 25, when the scanning beam luminous flux (141 (el)) is inclined and propagates in the height direction, FIG. When the scanning optical system and the inspection optical system are relatively moved by the optical axis direction moving stage (25a), the lens frame and the scanning beam luminous flux (141) are moved when the position of the objective lens is moved (from 8f to 8g). ) The crossing height with fluctuates. At that time, adjustment in the height direction is required in the same manner as the configuration operation shown in the seventh embodiment.

  Although not shown in FIGS. 25 and 27, a height measuring device for detecting the movement amount in the height direction is added, so that the relative movement amount between the scanning optical system and the inspection optical system can be calculated. It is possible to feed back to the data related to the height of the measurement result of the luminous flux.

Further, in the present embodiment, as the ninth example, for the scanning optical system inspection apparatus as each example described above, the step of continuously lighting the light source, the step of receiving the continuously lit beam beam, and the received beam beam And the step of adjusting the shielding means until the scattering is eliminated, and the light beam is received without receiving the noise light due to the scattering. You may inspect by a method.
The details of each of these steps are as in the above-described embodiments.

  As described above, according to the ninth embodiment, in the scanning optical system inspection apparatus as each of the above-described embodiments, the beam dot is located at the position where the beam light beam is scattered by the lens frame in the blinking state and is incident on the inspection target region. Since there may be no, there is no need to use the continuous lighting state that makes it possible to determine whether or not the light is incident on the inspection target area when scattered by the lens frame. It is possible to provide a scanning optical system inspection method that can adjust the shielding means until it can be removed.

  In addition, this embodiment is a tenth example in which a light source and a beam scanned by an element that modulates the beam beam emitted from the light source, scans the modulated beam beam, and reflects the beam beam to form a reflection image. When inspecting the optical characteristics of a scanning optical system mounted on an image product having a system for generating an image by forming an image of a light beam on a photosensitive drum or the like, a step of continuously lighting a light source, and a beam light beam that is continuously lit Can be lit with no noise due to scattering, including a step of detecting scattered light data scattered by the frame of the imaging means of the inspection optical system, and a step of deriving a period during which the light source can be lit. It is also possible to turn on and receive the light beam during the period.

  Thus, according to the tenth embodiment, when the light beam is scattered by the lens frame, the noise light is continually lit so that it can be inevitably determined whether or not the light beam enters the inspection target area. When it occurs, the light source lighting period is narrowed until the noise light can be completely removed, the period during which no scattering occurs is derived, the light source is turned on only within that period, and the beam light flux is acquired. It is possible to provide a scanning optical system inspection method that can inspect and measure optical characteristics without being affected by the above.

  As the tenth embodiment described above, for example, the light reception image of the noise light shown in FIG. 21 is extracted by continuous lighting, and when the light reception image of the noise light is confirmed, the width of the LD control pulse is reduced from DC to pulse. Then, by reducing the pulse width until no received light image of noise light is confirmed, it is possible to derive the width that is lit only in the region to be inspected as shown in FIG. It is possible to automate the specification of the inspection target area.

  In addition, as an eleventh example, this embodiment sets the input value for continuously lighting the light source to zero outside the litable period, and before and after the lit period within the litable period. A bias may be input to the light source.

  As described above, according to the eleventh embodiment, in the scanning optical system inspection method as the tenth embodiment described above, the scanning beam flux overlaps the light amount on the photosensitive member. Because it greatly affects the acquisition result, the lamp frame is completely extinguished outside the inspection target area so that no scattering occurs in the lens frame, and the bias light is lit before and after the inspection target position without being affected by noise light. It is possible to provide a scanning optical system inspection method capable of accurately acquiring superimposed optical characteristics.

As the eleventh embodiment described above, for example, as shown in FIG. 29, when the dot (6a) of the scanning beam is the inspection object, the LD is completely turned off before and after that, and the beam profile shown in FIG. (28)
However, in the practical stage, the bias current is often injected in consideration of the responsiveness of the LD, and the bias light (27) exists around the dot (6a) in FIG. Since the scanning beam flux moves on the photosensitive member while the light amount is superimposed on the light receiving surface in the present inspection apparatus, the light amount distribution in FIG. 29 becomes the meaning profile (6b) in FIG.
Therefore, when the inspection target is a dot (6a), it is necessary to emit the bias light (27) in an area where no reflection or scattering occurs on the objective lens frame. By this method, inspection and measurement can be performed under the same conditions as in practical use without generating noise light.

  As described above, the scanning beam of the scanning optical system propagates with a specific angle at the position in the main scanning direction. In actual operation when the scanning optical system is mounted on the product, the beam is modulated by the light source control pulse and continuously exists as dots on the scanning line. It is possible to determine whether or not the final output of the scanning optical system satisfies the specifications by verifying the beam flux in detail. In order to verify the scanning beam luminous flux in detail, it is necessary to improve the resolution of the inspection optical system, and it is effective to apply a lens to the inspection optical system, but the beam luminous flux continues in the main scanning direction. Therefore, there is a problem that the beam light beam outside the inspection target region is originally scattered by the mechanical element and enters the inspection target region as noise light.

In a conventional inspection optical system, it is not an exaggeration to say that this phenomenon always occurs somewhere in the main scanning position. When the inspection object and noise light coexist, the noise light must be removed because it is obtained by superimposing.
According to the above-described embodiments of the present invention, it is possible to inspect and verify the scanning beam light flux in the entire region in the main scanning direction, to verify the optical characteristics of the product, and to guarantee the quality.

The above-described embodiment and each example are preferred embodiments of the present invention, and various modifications can be made without departing from the spirit of the present invention.
For example, unlike scanning beams, beam beams do not exist continuously, but for inspection of image products using light source arrays such as LD arrays and LED arrays scattered in close proximity to the inspection target area. Application is also possible.

It is a figure which shows typically the apparatus (image forming apparatus) provided with the scanning optical system used as a test object. It is a figure which shows the example of the dot row imaged with the apparatus of FIG. It is a figure which shows the state in which bias light exists in the background of a dot row. It is a figure which shows the relationship between the light quantity of bias light, and the threshold value to which a photosensitive body responds. It is a figure which shows the state which test | inspects a test object with a scanning optical system test | inspection apparatus. It is a figure which shows typically the optical system and light-receiving surface in this scanning optical system test | inspection apparatus. It is a figure which shows a mode that the light from the outer side of an entrance pupil (15a) turns into noise light. It is a figure which shows the state which noise light superimposed on the beam of a test object. It is an example of a real image of the light reception image of a scanning beam light beam and noise light. It is an example of a real image of the light reception image of a scanning beam light beam and noise light. It is an example of a real image of the light reception image of a scanning beam light beam and noise light. It is a perspective view which shows the state which provided the light-shielding plate in the objective lens. It is a figure which shows typically the optical system and light-receiving surface in the scanning optical system inspection apparatus of the state which provided the light-shielding plate. It is a figure which shows a mode that scattered light generate | occur | produces with the incident light from a front. It is a figure which shows the state which noise light superimposed on the beam of a test object. It is a figure which shows the 1st Example which provided the moving mechanism which moves a light-shielding plate in a scanning optical system test | inspection apparatus. It is a figure which shows the state which further provided the moving mechanism in this scanning optical system inspection apparatus. It is a figure which shows the 2nd Example which provided the rotation mechanism which rotates a light-shielding plate in a scanning optical system test | inspection apparatus. It is a figure which shows the re-imaging image example of the scanning beam light beam at the time of lighting LD continuously. It is a figure which shows the image example of the scanning beam light beam at the time of continuous lighting at the time of the setting of the light-shielding plate without a noise image. It is a figure which shows the example of an image which emphasized the image (17g) of noise light. It is a figure which shows the structural example as a 3rd, 4th Example of this invention. It is a figure which shows the structural example as a 5th, 6th Example of this invention. It is a perspective view which shows the example of a frame structure of an objective lens. It is a figure which shows the structural example which implement | achieves the 7th Example of this invention. It is a figure which shows the state which displaced the position of the noise light by the 7th Example. It is a figure which shows the state which the scanning beam light beam is inclining and propagating in the height direction. It is a figure which shows the example of an imaging state by lighting in a 10th Example. It is a figure which shows the example of a test object dot in an 11th Example. It is a figure which shows the example of a beam profile in an 11th Example.

Explanation of symbols

1-1c Polygon mirror 2-2c LD unit 3-3c fθ lens 4-4c Imaging surface of scanning optical system 5-5d Scanning optical system 6, 6a Scanning beam luminous flux at dot lighting 7 Scanning beam luminous flux bias light 8- 8g Objective lens 9-9c Two-dimensional CCD area sensor 10-10f Objective lens frame 11-11i Lens constituting objective lens 12-12c Aperture stop of objective lens 13-13d Optical axis of objective lens 14-14k Scanning beam 15 -15b Entrance pupil (object plane)
16 to 16b Light receiving surface 17 to 17h Noise light 18 to 18e Shading plate 19, 19a Shading plate moving stage 20 Shading plate moving stage 21 Shading plate rotating stage 22 to 22b Scanning beam luminous flux 23, 23a Base 24, 24a in continuous lighting Optical system moving stage 25, 25a Scanning optical system moving stage 26 Scanning optical system height moving stage 27 Bias light 28 Beam profile when dots are lit

Claims (10)

A scanning optical system inspection apparatus that inspects optical characteristics of an apparatus that forms an image using a beam of light emitted from a scanning optical system including a light source,
A light receiving means for receiving a beam of light emitted from the scanning optical system;
Imaging means for forming an image of the beam on the light receiving surface of the light receiving means;
It has a long opening in a direction in which a light beam flux scanning direction perpendicular, and shielding means for the noise light generated from the light beam flux outside the inspection areas by the scanning optical system inspection apparatus for shielding so as not to re-imaged on the light receiving surface ,
A scanning optical system inspection apparatus comprising: an adjusting unit that adjusts an installation state of the shielding unit. Before Symbol opening of the shielding means, according to claim 1 scanning optical system inspection apparatus, wherein a provided in the beam incident side of the imaging means. It said adjustment means, optical scanning according to claim 1 or 2, characterized in that said shielding means by moving perpendicular to the optical axis of the imaging means is a moving mechanism for adjusting the position of the shielding means System inspection equipment. The adjusting means, the scanning optical system inspection apparatus according to claim 1 or 2, characterized in that by rotating the shielding means is a rotating mechanism that adjusts the angle of the shielding means. A moving means for moving the light receiving means and / or the imaging means in the scanning direction in order to receive the light beam emitted from the scanning optical system at a plurality of positions;
4. The scanning optical system inspection according to claim 3, wherein the position of the shielding means is adjusted by the moving mechanism according to an angle of a light beam incident on the imaging means at a position moved by the moving means. apparatus. A moving means for moving the light receiving means and / or the imaging means in the scanning direction in order to receive the light beam emitted from the scanning optical system at a plurality of positions;
5. The scanning optical system inspection according to claim 4, wherein the angle of the shielding means is adjusted by the rotating mechanism according to an angle of a beam beam incident on the imaging means at a position moved by the moving means. apparatus. First moving means for moving the light receiving means and / or the imaging means in the scanning direction in order to receive the light beam emitted from the scanning optical system at a plurality of positions;
A second moving means for moving the light receiving means and / or the imaging means relative to the scanning optical system in the optical axis direction of the imaging means;
The position of the shielding means is adjusted by the moving mechanism according to the angle of the beam of light incident on the imaging means at the position moved by the moving means and / or the second moving means. The scanning optical system inspection device according to claim 3. First moving means for moving the light receiving means and / or the imaging means in the scanning direction in order to receive the light beam emitted from the scanning optical system at a plurality of positions;
A second moving means for moving the light receiving means and / or the imaging means relative to the scanning optical system in the optical axis direction of the imaging means;
The angle of the shielding means is adjusted by the rotation mechanism according to the angle of the beam of light incident on the imaging means at the position moved by the moving means and / or the second moving means. The scanning optical system inspection device according to claim 4. The scanning optical system modulates a beam beam emitted from the light source, scans the modulated beam beam, and forms an image of the beam beam scanned by an element for reflecting and imaging the beam beam on a photosensitive drum or the like. scanning optical system inspection apparatus according to any one of claims 1 to 8, characterized in that provided in the apparatus having a system for generating an image Te. A scanning optical system inspection method for inspecting optical characteristics of a device that forms an image using a beam of light emitted from a scanning optical system including a light source,
A lighting step of continuously lighting the light source;
A light receiving means having a light receiving surface for forming an image of the beam of light emitted from the scanning optical system receives a continuously lighted beam of light; and
A separation step of separating received beam flux data and scattered light data scattered by the beam flux;
Further comprising an adjusting step of adjusting the noise light generated from the inspection target region outside of the beam flux by the scanning optical system inspecting method an installation state until the scattering disappears shielding means for shielding so as not to re-imaged on the light receiving surface A scanning optical system inspection method characterized by the above.