JP2006267716A - Light beam deflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light beam deflector capable of high-speed and high-quality image formation by deforming a deflection member and properly correcting astigmatism so as to compensate the astigmatism and the like generated by a centrifugal force. <P>SOLUTION: Respective support plates 43 of a fastening member 39 formed with material having a linear expansion coefficient different from the linear expansion coefficient of material of the deflection member 41 which has an outline formed in approximately cubic shape, is provided with a reflection surface 38 along a diagonal therein and is constituted in a prism shape are respectively stuck to both edge surfaces of the deflection member 41 and are held. By setting the temperature of the deflection member 41 to a temperature different from the manufacture temperature when the support plates 43 are respectively stuck to the both edge surface parts of the deflection member 41, a distortion is caused between an incident surface 41A of a light beam and an emission surface 41B of the deflection member 41 by the difference of deformation amount generated by the difference of the linear expansion coefficients, the astigmatism as the desired state for compensation is produced and the astigmatism which is produced in the deflection member 41 by the other factors is compensated by the astigmatism for correction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  Astigmatism suitable for use in an inner drum exposure apparatus (inner surface scanning type light beam scanning exposure apparatus) that scans and exposes a photosensitive surface disposed on the inner surface of a cylindrical drum by a laser beam scanning optical system. The present invention relates to a light beam deflector that can correct the above.

  Generally, a photosensitive lithographic printing plate (so-called PS plate) is used for offset printing. In the field of lithographic printing, laser exposure processing is performed based on digital data from a computer or the like, and development processing is performed to convert a latent image formed on the photosensitive lithographic printing plate into a visible image by an automatic processor. A CTP (Computer to Plate) system for making a printing plate directly has been put into practical use.

  In such a CTP system, an inner drum exposure device (inner surface scanning) that conducts a scanning exposure process by introducing a light beam such as a laser beam onto the photosensitive surface of a photosensitive lithographic printing plate that is a recording medium disposed on the inner peripheral surface of a cylindrical drum. Type light beam scanning exposure apparatus) is widely used.

  This inner drum exposure apparatus includes a spinner mirror device as a light beam deflector (monogon scanner). This spinner mirror device reflects a condensed beam from the optical system on the light source side to a spinner mirror that is rotationally driven at high speed, performs deflection scanning in the main scanning direction on the photosensitive surface of the recording medium, and By performing sub-scanning by moving the spinner mirror portion at a constant speed in the axial direction of the arc central axis of the inner drum support by the sub-scanning moving means, exposure processing is performed on the entire photosensitive surface of the recording medium.

  As a conventional light beam deflector (monogon scanner), a spin motor module having wavefront aberration correction means for correcting deformation when a tilting mirror (spinner mirror) is rotated at high speed has been proposed. Yes. In this light beam deflector (monogon scanner), an inclined mirror is arranged inside a cylindrical casing provided with an opening along the optical path. This inclined mirror is inclined at an angle of 45 degrees with respect to the center line of the cylindrical housing.

  In this light beam deflector, an incident light beam is incident from an opening of a cylindrical housing and reflected by an inclined mirror. The reflected light beam is emitted from a side opening formed in the side surface of the cylindrical housing and is collected on the recording medium.

  Since this cylindrical casing is rotated at a high speed (10,000 rpm or more) in order to scan the optical beam, the inclined mirror is deformed by a centrifugal force and an aberration is generated in the optical beam.

  Therefore, in the wavefront aberration correcting means of the conventional light beam deflector, an inclined mirror as a deflecting member (mirror etc.) is installed inside a cylindrical housing which is a mounting member for supporting and fixing that is rotated at high speed. A wavefront that eliminates aberration by attaching an optical flat glass plate as a wavefront aberration correction member to the opening of the cylindrical housing so that the angle can be adjusted, and adjusting the relative angle of the optical flat glass plate with the tilt mirror. Aberration correction is performed (for example, refer to Patent Document 1).

  Some light beam deflectors (monogon scanners) use ball prisms (internal reflection prisms) as deflecting members. In such a light beam deflector using a ball prism, a centrifugal force generated when the ball prism is rotated at a high speed causes distortion on the reflection surface and the light incident / exit surface, and a focal point in the deflection direction and a direction perpendicular thereto. There is a problem that the position is different (astigmatism), it is difficult to keep the beam spot small on the exposure surface, and the image quality is deteriorated.

  As a means for avoiding this problem, the angle of the optical flat glass plate can be adjusted to cancel the astigmatism generated by the centrifugal force in the ball prism by using the wavefront aberration correcting means of the conventional light beam deflector described above. Thus, means for mounting on the incident surface side and the exit surface side of the ball prism can be considered.

However, when this means is used, an optical flat glass plate processed and manufactured with high precision, or an optical flat glass plate is mounted on the entrance surface side and the exit surface side of the ball prism so that the angle can be precisely adjusted. A complicated and expensive structure is required. Further, with the wavefront aberration correction means of the conventional light beam deflector, it has been difficult to adjust the amount of astigmatism according to the amount of astigmatism.
US Patent No. 5,768,001

  In view of the above-described problems, the present invention provides a deflecting member that cancels astigmatism caused by centrifugal force, astigmatism generated during the manufacture of a prism-shaped deflecting member having a reflecting surface therein, and the like. It is an object of the present invention to newly provide a light beam deflector capable of appropriately correcting astigmatism by deformation and enabling high-speed and high-quality image formation.

  According to a first aspect of the present invention, there is provided a light beam deflector comprising: a deflecting member configured in a prism shape having an outer shape formed in a substantially cubic shape and having a reflecting surface along a diagonal line; and linear expansion of a material of the deflecting member A fastening member that is formed of a material having a linear expansion coefficient different from the coefficient, and that holds and holds support plates on both end portions of the deflection member, and a motor in which the fastening member is integrally installed at the tip of the rotating shaft. In the light beam deflector having the deflection member, the temperature of the deflection member is set to a temperature different from the manufacturing temperature when the support plate is adhered to each end surface, and the deformation amount due to the difference in linear expansion coefficient between the deflection member and each support plate is set. Due to the difference, distortion generated on the incident surface and the exit surface of the light beam of the deflecting member causes astigmatism that is required for the correction, and the astigmatism for correction causes the deflecting member due to other factors. Caused non Characterized by being configured to cancel the aberration.

  By configuring as described above, the linear expansion of the deflecting member is performed by controlling the temperature of the deflecting member and the fastening member holding the deflecting member to a predetermined temperature when performing the scanning exposure process with the light beam deflector. For example, due to the astigmatism for correction generated by the elastic strain of the deflection member caused by the difference between the coefficient and the linear expansion coefficient of the fastening member, for example, the deflection member generated by the centrifugal force when the deflection member is rotated by the motor Astigmatism caused by deformation, or astigmatism that occurs on the reflecting surface due to distortion or manufacturing error during processing of the deflecting member can be corrected so as to cancel. Therefore, it is possible to provide a light beam deflector that can be manufactured at a low cost with a simple configuration, and that can correct astigmatism and enables high-speed and high-quality image formation.

  According to a second aspect of the present invention, in the light beam deflector according to the first aspect, by heating a part of the rotating shaft, the support plates are attached to the both end surface portions of the deflecting member, respectively, to the required temperature. A temperature control means for heating and holding is provided.

  By configuring as described above, in addition to the operation and effect of the invention described in claim 1 described above, temperature control means can be arranged near the fastening member to enable appropriate temperature control.

  According to a third aspect of the present invention, in the light beam deflector according to the first or second aspect, the support plate is attached to each end face of the deflecting member, and the required constant temperature higher than the manufacturing temperature. It is characterized in that the incident surface and the exit surface of the light beam of the deflecting member are each elastically deformed into a cylindrical concave surface by heating to a cylindrical shape.

  According to the light beam deflector of the present invention, the deflecting member cancels astigmatism generated by centrifugal force and astigmatism generated at the time of manufacturing the deflecting member configured in a prism shape having a reflecting surface inside. As a result, it is possible to easily and inexpensively manufacture a light beam deflector capable of appropriately correcting astigmatism and forming a high-speed, high-quality image.

  Embodiments of the light beam deflector according to the present invention will be described with reference to FIGS. The light beam deflector according to the present embodiment uses a photosensitive lithographic printing plate (so-called PS plate) for offset printing as a recording medium, performs laser exposure processing based on digital data from a computer or the like, and performs photosensitivity with an automatic processor. It is suitable for use in a CTP system in which a latent image formed on a photolithographic printing plate is subjected to a development process for converting it into a visible image and directly plate-making a printing plate.

  1 and 2 show a schematic configuration of a CTP system including an internal drum type image forming apparatus (inner drum exposure apparatus) as a light beam deflector according to the present embodiment.

  In this CTP system, the automatic feeding device 10 of the printing plate supply cassette 20 and the PS plate (recording medium) 22 which is a photosensitive lithographic printing plate in the printing plate supply cassette are separated and supplied one by one. The apparatus 12 includes an inner drum exposure device 14, a buffer device 16, and a development processing device 18.

  In this CTP system, as a recording medium to be subjected to exposure processing, for example, a PS plate or a photopolymer plate in which an image recording layer containing a photosensitive material is formed on a support which is a thin aluminum plate, a silver salt type photosensitive material, or the like Can be used.

  The automatic feeding device 10 in this CTP system stores a plurality of printing plate supply cassettes 20 carried by an operator from the outside on a storage shelf 24 and supplies the required printing plate supply cassettes 20 to the sheet supply device 12. To do.

  The sheet feeding device 12 opens the lid of the supplied printing plate supply cassette 20 and separates the bundle of PS plates 22 accommodated therein by the separation roller 28 one by one while pulling up the bundle by the lifting mechanism 26. To the inner drum exposure device 14. The sheet feeding device 12 includes a slip sheet removing unit 32 that separates and stocks the slip sheet 30 sandwiched between the stacked PS plates 22 to protect the photosensitive surface.

  As shown in FIGS. 2 and 3, the inner drum exposure device 14 as a light beam deflector in the CTP system has an inner surface drum 34 having a circular arc inner peripheral surface shape (a shape constituting a part of a cylindrical inner peripheral surface) as a parent body. The PS plate 22 is supported along the inner peripheral surface of the inner drum 34.

  In this inner drum exposure device 14, the PS plate 22, which is an unrecorded recording medium, is held in a state of being in close contact with the inner peripheral surface of the inner drum 34 by a vacuum suction means (not shown), and then an exposure process. I do.

  In the inner drum exposure device 14, a spinner mirror device 36 as a light beam deflector is disposed at the center of the arc of the inner drum 34.

  As shown in FIGS. 3 and 4, in the spinner mirror device 36, a fastening member 39 as a holder (mounting member) is integrally installed at the tip of the rotating shaft 40, and the deflection member 41 is attached to the fastening member 39. Install.

  The deflecting member 41 is a so-called internal reflection prism or cubic prism, and is configured as a prism having a substantially cube-shaped outer shape and having a reflective surface 38 along a diagonal line. A so-called ball prism can be used.

  In the inner drum exposure apparatus 14, the fastening member 39 is formed in a substantially U shape, and the support plate 43 erected in a bifurcated manner in the fastening member 39 is formed in a rectangular flat plate shape parallel to each other.

  In this fastening member 39, the opposing side surfaces of the deflecting member 41 that are opposite to each other with the end sides of the reflecting surface 38 crossing diagonally in a state in which the deflecting member 41 is sandwiched between the pair of supporting plates 43 are respectively supported. Affix to the inner surface of the plate 43 and integrate.

  In the inner drum exposure device 14, an epoxy resin, an ultraviolet coin resin, or the like can be used as an adhesive used to stick the deflection member 41 to the support plate 43.

  In this spinner mirror device 36, a rotating shaft 40 in which a deflection member 41 having a reflecting surface 38 is integrated by a fastening member 39 that is a holder (mounting member) is rotated at high speed by a motor 45 as a drive source controlled by a control device. (For example, 10,000 rpm or more) In the spinner mirror device 36, the rotation center axis of the rotation shaft 40 is arranged so as to coincide with the arc center axis of the inner surface drum 34.

  In the spinner mirror device 36, the light beam projected from the optical system on the light source side is reflected by the reflecting surface 38 of the rotating deflection member 41, and scanning exposure in the main scanning direction is performed on the photosensitive surface of the PS plate 22. I do.

  The spinner mirror device 36 performs sub-scanning by being controlled to move at a constant speed in the axial direction of the arc central axis of the inner drum 34 (direction penetrating from the front surface to the back surface in FIG. 2) by the sub-scanning moving means.

  For this reason, the spinner mirror device 36 is configured such that the rotation of the motor 45 is controlled by a spinner driver of a control device (not shown) and the movement is controlled in the sub-scanning direction by the sub-scanning moving means.

  For example, as shown in FIG. 3, the sub-scanning moving means includes a sub-scanning guide mechanism for moving the spinner mirror device 36 in the axial direction (sub-scanning direction) of the arc central axis of the inner surface drum 34, and the spinner mirror device 36. Position control means for controlling movement adjustment so that the center of rotation of the reflecting surface 38 of the deflecting member 41 coincides with the arc central axis of the inner surface drum 34 during movement.

  The sub-scanning guide mechanism of the spinner mirror device 36 includes a linear guide mechanism 50 and a ball screw feed mechanism 52.

  The linear guide mechanisms 50 are arranged so as to be parallel to both ends in the longitudinal direction along the arc central axis of the semicircular arc in the inner drum 34 of the inner drum exposure device 14.

  A support frame 54 having a spinner mirror device 36 disposed in the middle is attached to the linear guide mechanisms 50 disposed in parallel so as to bridge, and the spinner mirror device 36 disposed on the support frame 54 is attached to the inner drum 34. It is configured to be movable along the arc center axis.

  Further, the support frame 54 on which the spinner mirror device 36 is arranged extends from one linear guide mechanism 50 at one end thereof and is connected to the ball screw feed mechanism 52. The ball screw feed mechanism 52 is configured to move the mover 58 by screwing the mover 58 into the feed screw rod member 56 and rotating the feed screw rod member 56 by a rotation control mechanism (not shown). To do.

  The spinner mirror device 36 configured in this manner reflects the light beam projected from the optical system on the light source side and modulated according to the image information to the rotating reflecting surface 38 to perform scanning exposure in the main scanning direction. While performing, a process of recording a two-dimensional image on the entire recording surface (photosensitive surface) of the PS plate 22 is performed by moving the spinner mirror device 36 in the sub-scanning direction.

  The buffer device 16 provided in the CTP system has a function of carrying the PS plate 22 exposed by the inner drum exposure device 14 into the development processing device 18 at a required timing by adjusting the conveyance speed.

  The development processing device 18 performs development processing on the exposed PS plate 22 that has been carried in to visualize the latent image, and completes the plate making of the printing plate.

  Next, means for correcting astigmatism provided in the spinner mirror device 36 configured as described above will be described.

  The means for correcting this astigmatism is obtained by controlling the temperature of the portion of the deflection member 41 and the fastening member 39 holding the deflection member to a predetermined temperature when performing the scanning exposure process with the spinner mirror device 36. Centrifugal when the deflection member 41 is rotated by the motor 45 due to correction astigmatism generated by the elastic strain of the deflection member 41 caused by the difference between the linear expansion coefficient of the member 41 and the linear expansion coefficient of the fastening member 39. Astigmatism caused by deformation of the deflecting member 41 caused by force, or astigmatism occurring on the reflecting surface 38 due to distortion or manufacturing error during processing of the deflecting member 41 is corrected so as to cancel.

  Furthermore, if necessary, a combination of astigmatism generated by centrifugal force when the deflecting member 41 is rotated and astigmatism caused by distortion or manufacturing error in the fabrication of the deflecting member 41 is combined. A means for correcting astigmatism may be configured so that the generated astigmatism can be corrected.

  In the means for correcting astigmatism, the amount of astigmatism generated by the centrifugal force when the deflection member 41 is rotated during scanning exposure and, if necessary, distortion during processing of the deflection member 41 are manufactured. And the astigmatism amount caused by manufacturing errors are obtained in advance by an astigmatism amount detecting means such as optical measurement or dynamic simulation.

  The astigmatism correcting means shown in FIGS. 3 and 4 is configured such that the linear expansion coefficient of the material of the deflecting member 41 and the linear expansion coefficient of the material of the support plate 43 are different. The deflection member 41 is made of optical glass. The support plate 43 can be made of metal such as iron or aluminum, or other materials.

  In this means for correcting astigmatism, for example, when the deflecting member 41 is made of optical glass and the support plate 43 is made of iron, iron has a larger linear expansion coefficient than optical glass. When the support plates 43 are attached to both end surface portions of the substrate, the support plates 43 attached to the both end surface portions of the deflecting member 41 are larger than the deflecting member 41 when heated to a temperature higher than the manufacturing temperature at the time of manufacture. Therefore, the deflection member 41 is deformed as shown in FIG.

  That is, in the deformed state of the deflecting member 41 when heated to a temperature higher than the manufacturing temperature shown in FIG. 5, the incident surface 41A of the deflecting member 41 and the exit surface 41B of the deflecting member 41 become cylindrical concave surfaces, respectively. It is elastically deformed to form a concave lens.

  Further, the curvature radius of the cylindrical concave surface when heated has a characteristic that the curvature radius of the cylindrical concave surface becomes smaller as the temperature becomes higher than the manufacturing temperature.

  Further, when the support plate 43 is attached to both end surface portions of the deflecting member 41 and the support plate 43 is attached to both end surface portions of the deflecting member 41 and the temperature is lower than the manufacturing temperature when manufactured, Since each support plate 43 attached to both end portions of the deflecting member 41 is deformed so as to be smaller than the deflecting member 41, the deflecting member 41 is deformed as shown in FIG.

  That is, in the deformed state of the deflecting member 41 when the temperature is lower than the manufacturing temperature shown in FIG. 8, the incident surface 41A of the deflecting member 41 and the exit surface 41B of the deflecting member 41 become cylindrical convex surfaces, respectively. It is elastically deformed to constitute a convex lens.

  In addition, the curvature radius of the cylindrical convex surface when the temperature is lower than the manufacturing temperature by means of cooling or the like is said to decrease as the temperature of the cylindrical convex surface becomes lower than the manufacturing temperature. Has characteristics.

  Therefore, in the means for correcting this astigmatism, the reflecting surface 38 of the deflecting member 41 is deformed to be convex downward by the centrifugal force when the deflecting member 41 is rotated by the motor 45 in FIG. In the case of a cylindrical concave mirror as shown in the figure (a concave mirror having a curved surface in a cylinder), or a cylindrical concave mirror in which the reflecting surface 38 is convex downward as shown in FIG. The astigmatism generated in the case of an in-cylindrical curved mirror) is set to a predetermined temperature higher than the manufacturing temperature of the deflecting member 41 having the support plates 43 attached to both end portions, and the incident surface 41A of the deflecting member 41 And the exit surface 41B are corrected so as to cancel each other by elastically deforming them into cylindrical concave surfaces each having a predetermined radius of curvature.

  That is, when the reflecting surface 38 of the deflecting member 41 becomes a cylindrical concave mirror (a concave mirror having a curved surface in a cylinder) as shown in FIG. 6 due to centrifugal force when the deflecting member 41 is rotated or distortion during processing and the like. When considering a slit-like virtual light beam 51 incident in the sub-scanning direction of the reflecting surface 38 (direction in which the reflecting surface 38 is inclined with respect to the incident beam), the slit-like virtual light beam 51 is reflected by a plane mirror. As a result, focusing is performed on a relatively distant position L.

  At this time, as shown in FIG. 6, when a slit-like virtual light beam 53 incident in the main scanning direction of the reflection surface 38 (the direction in which the reflection surface 38 is orthogonal to the incident beam) is considered, The virtual light beam 53 is reflected by the concave mirror and is focused on a relatively close position M.

  Therefore, in this case, as shown in FIGS. 5 and 7, the incident surface of the deflecting member 41 is set by setting the deflecting member 41 having the support plates 43 attached to the both end surface portions to a predetermined temperature higher than the manufacturing temperature. 41A and the emission surface 41B are each elastically deformed into a cylindrical concave surface having a predetermined radius of curvature.

  Further, in this case, both end surface portions are formed so that the incident surface 41A and the exit surface 41B having a radius of curvature that can be appropriately corrected appear corresponding to the distortion amount of the reflecting surface 38 measured in advance as described above. The deflection member 41 to which the support plate 43 is attached is controlled to be set to a predetermined temperature higher than the manufacturing temperature.

  Thus, in the case of the conditions of the means for correcting astigmatism shown in FIG. 7, a slit-like virtual light beam incident in the main scanning direction of the reflecting surface 38 (the direction in which the reflecting surface 38 is orthogonal to the incident beam). An incident surface 41A having the function of a cylindrical concave lens and an output surface 41B appear on the optical path 53, and the focal position of the virtual light beam 53 incident in the main scanning direction of the reflecting surface 38 is relatively close. By moving away from the in-focus position M to the in-focus position L that is relatively far away, the focal position of the virtual light beam 51 incident in the sub-scanning direction of the reflecting surface 38 can be made coincident and appropriate exposure processing can be performed.

  Also, a cylindrical convex mirror (cylindrical curved convex mirror) in which the reflecting surface 38 of the deflection member 41 is convex upward as shown in FIG. 9 due to centrifugal force when the deflection member 41 is rotated or distortion during processing and the like. In this case, when considering the slit-like virtual light beam 51 incident in the sub-scanning direction of the reflection surface 38 (the direction in which the reflection surface 38 is inclined with respect to the incident beam), the slit-like virtual light beam 51 is The light is reflected by the plane mirror and focused on a relatively close position M.

  At this time, as shown in FIG. 9, when considering a slit-like virtual light beam 53 incident in the main scanning direction of the reflecting surface 38 (a direction in which the reflecting surface 38 is orthogonal to the incident beam), The virtual light beam 53 is reflected by the convex mirror and is focused at a relatively distant position L.

  Therefore, in this case, as shown in FIG. 8 and FIG. 10, the incident surface of the deflecting member 41 is set by setting the deflecting member 41 having the support plates 43 attached to both end surfaces to a predetermined temperature lower than the manufacturing temperature. 41A and the emission surface 41B are each elastically deformed into a cylindrical convex surface having a predetermined radius of curvature.

  Further, in this case, both end surface portions are formed so that the incident surface 41A and the exit surface 41B having a radius of curvature that can be appropriately corrected appear corresponding to the distortion amount of the reflecting surface 38 measured in advance as described above. The deflection member 41 to which the support plate 43 is attached is controlled to be set to a predetermined temperature lower than the manufacturing temperature.

  Thus, in the case of the condition of the means for correcting astigmatism shown in FIG. 10, a slit-like virtual light beam incident in the main scanning direction of the reflecting surface 38 (direction in which the reflecting surface 38 is orthogonal to the incident beam). An incident surface 41A having the function of a cylindrical convex lens and an output surface 41B appear on the optical path 53, and the focal position of the virtual light beam 53 incident in the main scanning direction of the reflecting surface 38 is relatively far away. By bringing the in-focus position L closer to the in-focus position M, it is possible to match the focal position of the virtual light beam 51 incident in the sub-scanning direction of the reflecting surface 38 and perform an appropriate exposure process.

  Next, although not shown, in the means for correcting this astigmatism, the incident surface 41A and the exit surface 41B of the deflecting member 41 are moved in the main scanning direction (with respect to the incident beam) due to distortion during manufacturing and manufacturing errors. Thus, this can be corrected when the reflecting surface 38 is a cylindrical convex surface that is curved in a direction orthogonal thereto.

  In this case, the incident surface 41A and the exit surface 41B of the deflecting member 41 are respectively formed as cylindrical concave surfaces by setting the deflecting member 41 with the support plates 43 attached to both end surface portions to a predetermined temperature higher than the manufacturing temperature. By being elastically deformed in such a direction, the incident surface 41A and the exit surface 41B of the deflecting member 41 form a flat surface and are corrected.

  Although not shown, the means for correcting astigmatism causes the incident surface 41A and the exit surface 41B of the deflecting member 41 to move in the main scanning direction (with respect to the incident beam) due to distortion during manufacturing and manufacturing errors. This can also be corrected when the reflecting surface 38 is a cylindrical concave surface curved in a direction perpendicular to the reflecting surface 38.

  In this case, the incident surface 41A and the exit surface 41B of the deflecting member 41 are set to be cylindrical convex surfaces by setting the deflecting member 41 having the support plates 43 attached to both end surface portions to a predetermined temperature lower than the manufacturing temperature. By being elastically deformed in such a direction, the incident surface 41A and the exit surface 41B of the deflecting member 41 form a flat surface and are corrected.

  As described above, when the exposure processing is performed by the spinner mirror device 36 using the means for correcting astigmatism, the exposure is performed by narrowing the beam spot on the photosensitive surface of the PS plate 22, so that even when the depth of focus is short. It is possible to improve the image quality by focusing the substantially all light beams on the beam spot, exposing the image with high accuracy without being adversely affected by the astigmatic difference, and forming a fine image.

  Further, in this spinner mirror device 36, as shown in FIGS. 3 and 4, in order to facilitate the operation of correcting astigmatism by means for correcting astigmatism, support plates 43 are respectively attached to both end surfaces. A temperature control means 47 is provided for the deflecting member 41 portion.

  This temperature control means 47 heats or cools a part of the rotating shaft 40 to thereby adjust the temperature of the support plate 43 integral with the rotating shaft 40 and the deflection member 41 attached to the support plate 43 to a required level. It is configured so that temperature control for changing and adjusting to an arbitrary temperature can be performed.

  The temperature control means 47 can be configured using a so-called thermoelectric element such as a heater, a cooler, or a Peltier element.

  In addition, the spinner mirror device 36 generates heat during scanning exposure, and the deflecting member 41 portion having the support plates 43 attached to both end surface portions is in a temperature state during use.

  Therefore, in this spinner mirror device 36, the means for correcting astigmatism is generated by a centrifugal force or the like when the deflection member 41 portion having the support plates 43 attached to both end surface portions is in a temperature state during use. In order to minimize temperature control, it is desirable that the astigmatism to be corrected is appropriately corrected.

  Therefore, as shown in FIG. 5 to FIG. 7, when the means for correcting astigmatism is configured on the condition that the deflection member 41 portion having the support plates 43 attached to both end surfaces is heated, Only the heating temperature difference for elastically deforming the incident surface 41A and the exit surface 41B of the deflecting member 41 into a cylindrical concave surface having a radius of curvature corresponding to the amount for appropriately correcting astigmatism is subtracted from the temperature during use. This value is set as the manufacturing temperature when the support plate 43 is bonded to each end surface of the deflecting member 41 for manufacturing.

  When the means for correcting astigmatism is configured in this way, the deflecting member 41 portion in which the spinner mirror device 36 is rotated to the use state and the support plates 43 are respectively attached to both end surface portions is in the temperature state during use. Then, the entrance surface 41A and the exit surface 41B of the deflecting member 41 are elastically deformed into a cylindrical concave surface having an appropriate amount of curvature radius, and astigmatism generated by centrifugal force or the like is appropriately corrected.

  Further, in this case, when the spinner mirror device 36 starts driving or when the rotation speed is lowered for standby, the deflection is performed by attaching the support plates 43 to both end portions of the spinner mirror device 36, respectively. When the temperature of the member 41 becomes lower than the temperature at the time of use, the temperature control means 47 is operated to maintain the temperature of the deflection member 41 with the support plates 43 attached to both end portions at the temperature state at the time of use. It is possible to reduce the waiting time until exposure processing can be performed quickly.

  Further, in this case, the surrounding air is heated by the heat generated by the motor 45 of the spinner mirror device 36 and the bearing portion of the rotary shaft 40 and the heat generated by the temperature control means 47 before the deflection member 41 is heated. In order to prevent the light beam from drifting on the optical path of the incident and reflected light beam and causing the light beam to fluctuate due to the temperature gradient generated in the air, the air is blown from the deflection member 41 side to the motor 45 side in the spinner mirror device 36. Thus, it is desirable to prevent a temperature gradient from occurring in the air hitting the optical path.

  Further, as shown in FIGS. 8 to 10, when the means for correcting astigmatism is configured on the condition that the temperature of the deflection member 41 portion where the support plates 43 are bonded to the both end surfaces is lowered, respectively. The temperature at which the incident surface 41A and the exit surface 41B of the deflecting member 41 are used is only a temperature difference that causes a temperature drop to elastically deform the cylindrical convex surface having a radius of curvature corresponding to the amount for appropriately correcting astigmatism. The value added to is set as the manufacturing temperature when the support plate 43 is bonded to both end surfaces of the deflecting member 41 and manufactured.

  That is, the support plates 43 are attached to both end surface portions of the deflecting member 41 in a high temperature state heated by a predetermined temperature difference that causes the temperature to drop, and the spinner mirror device 36 is turned to the use state to rotate both end surface portions. In addition, the deflection member 41 portion to which the support plate 43 is attached is used in a temperature state at the time of use, which is a predetermined low temperature compared to a high temperature state at the time of manufacture.

  When the means for correcting astigmatism is configured in this way, the deflecting member 41 portion in which the spinner mirror device 36 is rotated to the use state and the support plates 43 are respectively attached to both end surface portions is in the temperature state during use. Then, the entrance surface 41A and the exit surface 41B of the deflecting member 41 are elastically deformed into a cylindrical convex surface having an appropriate amount of curvature radius, and astigmatism caused by centrifugal force or the like is appropriately corrected.

  In the above-described means for correcting astigmatism, the direction of occurrence of astigmatism is determined depending on whether the temperature is higher or lower than the manufacturing temperature when the support plates 43 are attached to both end portions of the deflecting member 41 for manufacturing. The amount of astigmatism can be arbitrarily adjusted by the temperature difference from the manufacturing temperature.

  Therefore, in the means for correcting this astigmatism, the astigmatism of the deflecting member 41 is adjusted by adjusting the temperature of the deflecting member 41 portion where the support plates 43 are adhered to the both end surfaces to a temperature different from the manufacturing temperature. Any amount of astigmatism can be generated so as to cancel astigmatism generated by centrifugal force, and astigmatism generated by the spinner mirror device 36 can be corrected to form a high-quality image at high speed. And

  That is, in the spinner mirror device 36 using the means for correcting this astigmatism, only a part of the condensed light beam is focused on the exposure surface of the PS plate 22 and the focus of the other part of the light beam. Astigmatism difference that does not match is generated, and the image formed by exposure is prevented from being blurred and image quality is deteriorated, and high-quality image formation can be performed.

  Further, according to the means for correcting astigmatism, the amount of astigmatism can be adjusted with a simple configuration without adding any member to the deflection member 41 or the fastening member 39, so that the spinner mirror device 36 is inexpensive. Can be manufactured.

  In addition, this invention is not limited to embodiment mentioned above, Of course, it can take other various structures in the range which does not deviate from the summary of this invention.

It is a perspective view which shows schematic structure of the CTP system provided with the light beam deflector which concerns on embodiment of this invention. It is a schematic explanatory drawing which shows the structure inside the CTP system which concerns on embodiment of this invention. It is a principal part perspective view which takes out and shows the principal part of the inner drum exposure apparatus which concerns on embodiment of this invention. It is a general | schematic disassembled perspective view which shows the principal part of the spinner mirror apparatus which is a light beam deflector concerning embodiment of this invention. It is explanatory drawing of the principal part which shows the state which heated the deflection | deviation member part which each adhered the support plate to the both end surface parts in the light beam deflector concerning embodiment of this invention from manufacturing temperature. It is explanatory drawing of the principal part which shows the state of astigmatism when the reflective surface of the deflection | deviation member in the light beam deflector concerning embodiment of this invention becomes a convex state. The main part showing the state of correcting astigmatism when the reflecting surface of the deflecting member in the light beam deflector according to the embodiment of the present invention is convex downward by means for correcting astigmatism. It is explanatory drawing. It is explanatory drawing of the principal part which shows the state which cooled the deflection | deviation member part which each adhered the support plate to the both end surface parts in the light beam deflector concerning embodiment of this invention from manufacturing temperature. It is explanatory drawing of the principal part which shows the state of astigmatism when the reflective surface of the deflection | deviation member in the light beam deflector concerning embodiment of this invention becomes a convex state. The main part showing the state of correcting astigmatism when the reflecting surface of the deflecting member in the light beam deflector according to the embodiment of the present invention is convex upward by means for correcting astigmatism. It is explanatory drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automatic feeding apparatus 14 Inner drum exposure apparatus 18 Development processing apparatus 22 PS plate 34 Inner surface drum 36 Spinner mirror apparatus 38 Reflective surface 39 Fastening member 40 Rotating shaft 41 Deflection member 41A Incidence surface 41B Output surface 43 Support plate 45 Motor 47 Temperature control means

Claims (3)

A deflecting member configured in a prism shape with an outer shape formed in a substantially cubic shape and having a reflecting surface along a diagonal line inside;
A fastening member that is formed of a material having a linear expansion coefficient different from the linear expansion coefficient of the material of the deflection member, and that holds and holds support plates on both end surface portions of the deflection member,
A light beam deflector having a motor in which the fastening member is integrally installed at the tip of the rotating shaft,
The temperature is set to a temperature different from the manufacturing temperature when the support plate is attached to both end surfaces of the deflection member, and the difference in deformation amount due to the difference in linear expansion coefficient between the deflection member and each support plate. Astigmatism, which is a required condition for correction, is caused by distortion generated on the incident surface and the exit surface of the light beam of the deflecting member. An optical beam deflector configured to cancel astigmatism. 2. A temperature control means is provided for heating and holding the support plates attached to both end portions of the deflection member by heating a part of the rotating shaft to a required temperature. A light beam deflector according to 1. The incident surface and the exit surface of the light beam of the deflection member are heated by heating the support plates attached to both end portions of the deflection member to a required constant temperature higher than the manufacturing temperature. 3. The light beam deflector according to claim 1, wherein each of the light beam deflectors is elastically deformed into a cylindrical concave surface.

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