JP2008292539A - Optical scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein beams limited by an open part are reflected on a slit in the vicinity of the open part of the slit when a portion of beams pass through the open part of the slit, the returning light and irregularly diffused light caused by the reflection partially returns to a light source, so that stable beams are not emitted owing to the returning light and the irregularly diffused light, and as a result, a stable electrostatic latent image is not formed on a photoreceptor. <P>SOLUTION: An influence of the returning light and the irregularly diffused light is reduced by simplifying the structure of the slit used in the optical scanner, and a manufacturing process is simplified to provide an inexpensive optical scanner. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical scanning device used in an image forming apparatus such as a copying machine or a laser printer.

  As shown in FIG. 9, the conventional optical scanning apparatus includes a light source 1 in which a light emitting element that emits a beam is attached to a circuit board that is electrically driven so that it can be turned on and off independently. A collimator lens 2 that makes the emitted beam 8 substantially parallel, a cylinder lens 3 that collects the substantially parallel beam 8 in the sub-scanning plane, and a rotating multi-face that deflects and reflects the collected beam in the scanning direction. A scanning optical system including an optical deflector 4 (polygonal mirror rotation control means) including a mirror (polygon mirror), an fθ lens 5, a reflection mirror 6 and the like is provided.

  The beam 8 emitted from the light source 1 is deflected and reflected by the polygon mirror of the optical deflector 4 and is condensed by the fθ lens 5 to form an electrostatic latent image on the photosensitive member 7 and record the image on paper. .

  This optical scanning device 9 is a means for restricting an extra beam of the beam 8 that has passed through the collimator lens 2 and setting a spot diameter for allowing only a part of the beam to pass through, a limiting aperture (hereinafter referred to as “slit” "). Conventionally, an optical scanning device equipped with the slit 10 has become common.

As the slit 10 conventionally used, for example, as shown in FIG. 7, the end of the slit is bent into a U shape, and a convex portion formed on the housing 11 of the optical scanning device 9 is sandwiched and fixed. As shown in FIG. 8, a structure that is fixed with a screw 18 as shown in FIG. 8 is used.
Japanese Patent Laid-Open No. 5-19187 JP-A-6-43372

  When a part of the beam passes through the openings of these slits 10, in the vicinity of the opening of the slit 10, the beam limited by the opening (the beam that could not pass through the opening) is reflected by the slit 10, Return light and diffuse reflection occur.

  Some return light and irregular reflection generated by this reflection return to the light source. In this case, inside the light source, the beam is always fed back so as to stably emit the beam, but when the return light and irregular reflection enter the light source, a stable beam cannot be emitted, As a result, a problem that a stable electrostatic latent image cannot be formed on the photoconductor 7 occurs.

  In order to solve such a problem, that is, to prevent the light source from being affected by the return light and diffuse reflection, the slit has been improved in terms of the position and structure of the opening, and the structure has become complicated. .

  When the structure of the slit becomes complicated, the cost of the slit increases, and as a result, the cost of the optical scanning device increases.

  In recent years, along with a demand for downsizing and cost reduction of an optical scanning device, cost reduction is required for each component of the optical system, and a slit having a simple structure as much as possible has been desired.

  The present invention has been made in view of all the above-mentioned problems. By simplifying the structure of the slit, the inexpensive light that can reduce the influence of return light and irregular reflection and can simplify the manufacturing process. An object is to provide a scanning device.

  The present invention includes an optical system having a light source that emits a beam, a collimator lens that collimates the beam emitted from the light source, and a slit having an opening through which a part of the beam that has passed through the collimator lens passes. The present invention relates to an optical scanning device including a component and a housing for mounting an optical system component.

  The slit is a flat plate made of an elastic member, and the material thereof may be metal, plastic, or rubber.

  The housing provided with the slit in the optical scanning device is provided with a holding member formed integrally with the housing so that the slit can be held.

  By holding the slit with the holding member, it can be held curved.

  By holding the slit in a curved shape, the vicinity of the opening of the slit becomes a curved surface. Therefore, when a part of the beam passes through the opening, the return light and irregular reflection generated by the reflection of the beam return to the light source. The influence can be reduced.

  It is desirable that both ends of the slit have a structure that forms a hole or notch. With such a structure, since the elastic force at both ends of the slit is increased, it is easy to hold the slit on the holding member provided in the housing of the optical scanning device.

  The slit can be fixed with high accuracy by forming a positioning hole in the slit and forming a positioning projection on the holding member for positioning and holding the slit by fitting the positioning hole. Thereby, a good quality image can be formed.

  The slit is preferably a matte black surface-treated. This works to prevent return light and irregular reflection that occur when the beam is reflected by the slit, and can reduce the influence of the beam returning to the light source.

  The holding member has a central member that holds the vicinity of the opening of the slit, and an end member that holds both ends of the slit, and the central member and the end member each have a contact portion that contacts the slit, The contact portion of the end member is desirably provided at a position within a range of ± 10 mm with respect to the direction of the optical axis when the contact portion at the center is used as a reference.

  As described above, by simplifying the structure of such a slit, it is possible to provide an inexpensive optical scanning device that can reduce the influence of return light and irregular reflection and can simplify the manufacturing process.

  The present invention can provide an inexpensive optical scanning device that can reduce the influence of return light and irregular reflection, and can simplify the manufacturing process, by simplifying the structure of the slit used in the optical scanning device. There is an effect.

  The present invention will be described in detail with reference to FIGS.

  1 to 2 show an embodiment of a slit structure used in an optical scanning device according to the present invention. Note that the configuration of the optical scanning device that has been generally used conventionally will be omitted from the above description (see FIG. 9).

  FIG. 1 is a perspective view illustrating the structure of the slit of the optical scanning device according to the first embodiment. FIG. 2 is a plan view illustrating the structure of the slit of the optical scanning device according to the first embodiment. For ease of explanation, FIG. 1 shows a state before the slit is attached to the housing, and FIG. 2 shows a state after the slit is attached to the housing.

  As shown in FIG. 1, the slit 10 is a flat plate made of an elastic member (for example, a sheet metal of 0.1 mm), and has an opening through which a part of the beam passes.

  A holding member 12 for holding the slit 10 is integrally formed in a housing 11 for mounting optical parts of the optical scanning device such as a light source, a collimator lens, and a slit.

  The holding member 12 includes a central member 13 that holds the vicinity of the opening of the slit 10 and an end member 14 that holds both ends of the slit 10. The central member 13 and the end member 14 touch the slit, respectively. A contact portion 15 exists.

  The contact portion of the end member 14 is provided at a position of −2 mm with respect to the direction of the optical axis when the contact portion of the central portion 13 is used as a reference.

  The slit 10 is held curved by a central member 13 and an end member 14 which are end members 14.

  With such a holding member 12, the slit 10 can be held by the holding member 12 with respect to the direction of the optical axis and the direction perpendicular to the direction of the optical axis.

  Conventionally, when the vicinity of the opening of the slit 10 is straight and flat, when a part of the beam passes through the opening of the slit 10, the beam limited by the opening is near the opening of the slit 10. When the reflected light reflected by the slit 10 and the return light and irregular reflection generated by this reflection enter the light source, a stable beam cannot be emitted, resulting in the formation of a stable electrostatic latent image on the photoreceptor. There was a problem that could not be done. However, as shown in the present embodiment, by holding the slit 10 in a curved shape, the vicinity of the opening of the slit 10 becomes a curved surface, so that the return light and irregular reflection due to the reflection of the beam diffuse without directly returning to the light source. Therefore, the influence on the light source can be reduced. Therefore, a good quality image can be formed.

  By simplifying the structure of the slit 10 as described above, it is possible to provide an inexpensive optical scanning apparatus that can reduce the influence of return light and irregular reflection and can simplify the manufacturing process.

  FIG. 3 shows another embodiment according to the present invention. In addition, about the part same as the structure of the slit concerning Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted, and only a different point from Example 1 is demonstrated in detail.

  FIG. 3 is a perspective view showing the structure of the slit according to the second embodiment. For simplicity of explanation, FIG. 3 shows a state before the slit is attached to the housing, and the state after the slit is attached. Is the same as FIG. The difference from Example 1 is that holes 20 are formed at both ends of the slit.

  By forming such a slit, both ends of the slit can be easily bent. For this reason, it becomes easy to install a slit in the end member 14 of the holding member 12 provided in the housing of the optical scanning device, the assembly man-hour can be reduced, and as a result, an inexpensive optical scanning device is provided. Can do.

  The hole 20 may be a notch.

  In this embodiment, the same effect as that of the first embodiment can be obtained.

  4 to 6 show other embodiments according to the present invention. In addition, about the same part as the structure of the slit which concerns on Example 1 and Example 2, the same code | symbol is attached | subjected and description is abbreviate | omitted, and only the difference with Example 1 and Example 2 is demonstrated in detail. .

  FIG. 4 is a perspective view showing the structure of the slit according to the third embodiment. For ease of explanation, FIG. 4 shows a state before the slit is attached to the housing, and the state after the slit is attached. Is the same as FIG. The difference from the first and second embodiments is that a positioning hole 16 is formed in the slit 10 and a positioning protrusion 17 for positioning and holding the slit is formed in the holding member 16. .

  By forming the slit as described above, the opening of the slit that affects the beam formation can be held at a more accurate position, so that a higher quality image can be formed than in the first and second embodiments. An optical scanning device can be provided.

  Further, it may be as shown in FIG. 5 or FIG. 6 in which holes or notches are formed so that the elastic force at both ends of the slit is large (easy to bend).

  The above-described embodiments are illustrated for explanation, and the present invention is not limited thereto, and those skilled in the art will recognize from the claims, the detailed description of the invention, and the description of the drawings. Modifications and additions are possible without departing from the technical idea of the present invention.

  For example, it is free to form holes or notches at both ends of the slit so that the elastic force at both ends of the slit described in the embodiment is large, and shapes other than those shown in the embodiment may be adopted. Good.

  In addition, although the slits described in the embodiments are exemplified as being capable of being curved and held by the holding member, they may be held in an arc shape.

  The surface of the slits described in the examples is preferably matte black and surface-treated. This works to prevent return light and irregular reflection that occur when the beam is reflected by the slit, and can reduce the effect of returning to the light source.

  Further, the elastic member described in the embodiments may be plastic or rubber.

  Further, the central member of the holding member described in the embodiment may be one place or a plurality of places.

  In addition, in the first embodiment, the contact portion of the end member is provided at a position of −2 mm with respect to the direction of the optical axis when the contact portion of the center portion is used as a reference. If the position of the contact portion of the end member is within a range of ± 10 mm, the same effect as in the embodiment can be obtained.

  However, the range of the thickness of the slit to be held is excluded because it cannot be curved and held by the holding member described in the embodiment (the slit becomes straight). For example, when the plate thickness of the slit is 0.1 mm and the contact portion at the center is used as a reference, the slit does not bend even if the contact portion of the end member is installed within the range of ± 0.1 mm. It is because it cannot play.

It is a perspective view showing the structure of the slit concerning this invention. Example 1 It is a top view showing the structure of the slit concerning this invention. Example 1 It is a perspective view showing the structure of the slit concerning this invention. (Example 2) It is a perspective view showing the structure of the slit concerning this invention. (Example 3) It is a perspective view showing the structure of the slit concerning this invention. (Example 3) It is a perspective view showing the structure of the slit concerning this invention. (Example 3) It is a perspective view showing the structure of the conventional slit. It is a perspective view showing the structure of the conventional slit. It is a top view of the conventional optical scanning device.

Explanation of symbols

1 Light source 2 Collimator lens 3 Cylinder lens 4 Optical deflector (MPA)
5 fθ lens 6 reflection mirror
7 Photoconductor 8 Beam 9 Optical scanning device 10 Slit 11 Housing 12 Holding member 13 Central member 14 End member 15 Contact portion 16 Positioning hole 17 Positioning protrusion 18 Screw 19 Screw hole 20 Hole (notch)

Claims (5)

A light source that emits a beam;
A collimator lens that collimates the beam emitted from the light source;
A slit having an opening through which a part of the beam transmitted through the collimator lens passes;
An optical system component having
In an optical scanning device comprising a housing for holding the optical system component,
The slit is a flat plate made of an elastic member,
An optical scanning device characterized in that a holding member that holds the slit in a curved shape is formed integrally with the housing.   The optical scanning device according to claim 1, wherein holes or notches are formed at both ends of the slit. A positioning hole is formed in the slit,
The optical scanning device according to claim 1, wherein a positioning projection for positioning the slit by fitting the positioning hole is formed on the holding member.   4. The optical scanning device according to claim 1, wherein the surface of the slit is surface-treated with matte black. 5.   The optical scanning device according to claim 1, wherein the elastic member is metal, plastic, or rubber.

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