JP2002098920A - Laser scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser scanner which can introduce light to a photodetecting means, without having to use a reflecting mirror for exclusive use. SOLUTION: The laser scanner, which performs optical scanning by deflecting the laser beam flux from a laser unit by a light deflecting means 102 and condensing the laser beam flux as a light spot on a surface 105 to be scanned by an imagery optical system 103, includes a dustproof member 150 which is disposed to exist in a laser beam exit port of a device body, containing optical elements and prevents the infiltration of the dust into the device body, while allowing transmission of the laser beam and the photodetecting means 152, which receives part of the laser beam flux deflected by the light-deflecting means, in order to obtain the timing of optical scanning. Part of the dustproof member is provided with a reflecting surface 150a, such that the light reflected by the reflecting surface is introduced to the photodetecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a laser scanning device used for a PC, a digital facsimile, a laser printer, or the like, and in particular, a laser scanning device having a light detecting device for receiving a part of a laser beam deflected by a light deflecting device in order to take timing of the optical scanning. Related to the device.

[0002]

2. Description of the Related Art Conventionally, there has been known a laser scanning apparatus which deflects a laser beam from a laser unit by a light deflecting means, and condenses it as a light spot on a surface to be scanned by an imaging optical system to perform optical scanning. ing. In addition, an optical printer, a digital copying machine, or the like, which optically scans a photoconductive photoconductor provided in conformity with a surface to be scanned by the laser scanning device (optical scanning device) and forms an image by an electrophotographic process, is used. Image forming apparatuses are also known.

FIG. 6 shows an example of the laser scanning device. As shown, from the laser unit 4,
A laser beam converted into a parallel beam is emitted. This laser beam is condensed in the sub-scanning direction by the cylinder lens 101 and forms an image as a “long line image in the main scanning direction” at the position of the deflecting reflection surface of the polygon mirror 102. Polygon mirror 1
02 which constitutes a light deflecting means together with the optical motor 02
2A, when the polygon mirror 102 is rotated at a constant speed at a high speed, the laser beam reflected by the deflecting / reflecting surface is deflected at a constant angular velocity, passes through the fθ lens 103 which is an image forming optical system, and is turned back. The light is turned back by 104, and is condensed as a light spot on the surface of the photoconductive photoconductor 105 arranged in conformity with the surface to be scanned, thereby performing optical scanning.

On the other hand, at a position just before the effective area of the photosensitive member 105, a light detecting means 152 and a reflection mirror 151 for taking light for detecting the light (detection light) are provided. In this case, the optical path of the detection light is different from the optical path of the scanning light for scanning the photoconductor 105. That is, for each scan, a part of the scanning light is reflected by the reflection mirror 151 and guided to the light detecting means 152, and the timing of writing is set by a signal from the light detecting means 152, and the light scanning is performed.

Further, in such a laser scanning device, a dustproof member is provided in order to prevent dust such as toner and various dusts and dirt generated during the image forming process from entering the inside of the laser scanning device. I have. This dustproof member is adhesively fixed to the housing of the laser scanning device at the position of the laser light emission window of the laser scanning device, and prevents the penetration of various dusts while transmitting the laser light.

[0006]

As described above, the reflection mirror 105 for guiding the light to the light detecting means is a dedicated one as described above. However, as described above, since various components such as a dustproof member are provided in the laser scanning device, if the reflection mirror 105 is dedicated, the degree of freedom in the layout of the optical unit is reduced, and Parts and assembly costs increase.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser scanning device capable of guiding light to light detecting means without using a dedicated reflecting mirror. It is in.

[0008]

According to a first aspect of the present invention, a laser beam from a laser unit is deflected by a light deflecting unit and scanned by an imaging optical system. 2. Description of the Related Art In a laser scanning device that performs optical scanning by condensing a light spot on a surface, the laser scanning device is provided at a laser light emission port of a device body including an optical element, and is transmitted into a device body while transmitting laser light. A dust-proof member for preventing intrusion of dust, and a light detecting means for receiving a part of the laser beam deflected by the light deflecting means in order to take the timing of optical scanning. A reflecting surface is provided, and light reflected by the reflecting surface is guided to the light detecting means.

According to a second aspect of the present invention, in the first aspect, the reflection surface of the dustproof member is formed by applying a reflective coating to the surface of the dustproof member.

A third aspect of the present invention is characterized in that, in the first aspect of the present invention, the reflection surface of the dustproof member is formed by bonding the reflective member to the dustproof member.

Therefore, according to the above configuration, it is not necessary to arrange a dedicated mirror for guiding light to the light detecting means in the optical unit, and the degree of freedom of the layout of the optical unit is increased. In addition, it is possible to suppress an increase in component and assembly costs associated with the dedicated mirror, and to reduce costs.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a digital copying apparatus as an image forming apparatus to which the laser scanning device according to the present embodiment is applied. In this copying apparatus, a document to be copied is placed in a plane on a document glass 110 and is illuminated and scanned at a constant speed to the left in FIG. Along with this illumination scanning, the reflected light beam from the original is
13 to the imaging lens 114, the imaging lens 1
By the operation of 14, an image is formed on the solid-state image sensor 115 as a reduced image of the document. The movable mirror 113 couples the first mirror that reflects the light beam reflected from the document in a direction parallel to the document surface with the light beam reflected by the first mirror while moving at half the speed of the movement of the first mirror. And a roof mirror that reflects light toward the image lens 114.

When a document image is read in this manner, the read image information of the document is transmitted to a laser unit 4 of a laser scanning device provided as a unit below the document reading unit. And written on the photoconductive photoconductor 105 by optical scanning.

In the laser scanning device, a laser beam converted into a parallel beam is emitted from the laser unit 4. This laser beam is condensed in the sub-scanning direction by the cylinder lens 101 and forms an image as a “long line image in the main scanning direction” at the position of the deflecting reflection surface of the polygon mirror 102. When the polygon mirror 102 is rotated at a high speed and a constant speed by a polygon motor which constitutes a light deflecting means together with the polygon mirror 102, the laser beam reflected by the deflecting / reflecting surface is deflected at a constant angular velocity to form an imaging optical system. Is transmitted by the fθ lens 103, is turned back by the turning mirror 104, and is condensed as a light spot on the surface of the photoconductive photoconductor 105 arranged in conformity with the surface to be scanned. Done.

Prior to writing, the photosensitive member 105 is uniformly charged to a predetermined polarity by the charger 120, and image information is written by optical scanning by the laser scanning device.
Thus, an electrostatic latent image according to the image information is formed on the photoconductor 105. This electrostatic latent image is developed by the developing device 121 and visualized.

The transfer paper S is fed from inside the cassettes 130 and 132 or set on the manual feed table 131, is conveyed to the transfer unit, and the visible image is transferred by the transfer unit 122. After that, the transfer paper S is separated from the photoreceptor 105 by the separator 123, and then conveyed to the fixing device 126 by the conveyance belt 125, where the visible image is fixed and discharged outside the device. On the other hand, the photoconductor 105 after the transfer of the visible image is cleaned by the cleaning device 124.

The photosensitive member 105 has various components (e.g., a charger 120 and a cleaning device 124) related to the photosensitive member 105 in order to improve the maintenance and exchangeability thereof.
At the same time, it is unitized by being included in one case 160, whereby the photoconductor unit 159 is configured.
The replacement of the photoconductor 105 and the maintenance of the cleaning device 124 are performed with the photoconductor unit 159 pulled out from the front side of the apparatus main body and the unit 159 taken out of the apparatus main body.

Further, in the image forming apparatus as shown in FIG. 1, in order to prevent toner and various kinds of dust such as dust generated in the image forming process from entering the laser scanning device,
A dustproof member 150 made of glass or a transparent plastic material is provided. This dustproof member 150
Is provided at the laser beam emission port of the laser scanning device body including the optical element, and prevents various dusts from entering while transmitting the laser beam.

FIG. 2 is an enlarged sectional view of the periphery of the dustproof member 150. As illustrated, the dustproof member 150 is adhesively fixed to a housing 145 of the laser scanning device. A photoconductor unit 159 exists immediately below the dustproof member 150,
The case 160 of the photoconductor unit 159 is provided with a window through which light passes.

In this embodiment, as shown in FIGS. 3 and 4, a part of the dustproof member 150 is coated with a reflective coating (mirror vapor deposition) to form a reflective surface 150a. Transmission surface 15 that transmits light
0b. When the reflection surface 150a is formed on the dust-proof member 150 in this way, as shown in FIG.
The reflecting mirror 150 is reflected by the reflecting surface 150a of
Returning to 04, the light is reflected by the turning mirror 104 and guided to the light detecting means 152. On the other hand, light for scanning the photoconductor 105 passes through the transmission surface 150 b of the dustproof member 150 as it is, and scans the photoconductor 105.

As described above, in this embodiment, the reflecting surface 150a is formed on the dustproof member 150, and the reflecting surface 150a
Since the light reflected by the light detecting means 152 is guided to the light detecting means 152, it is not necessary to arrange a dedicated mirror for guiding the light to the light detecting means 152 in the optical unit, and the degree of freedom of the layout of the optical unit is widened. In addition, it is possible to suppress an increase in component and assembly costs associated with the dedicated mirror, and to reduce costs.

Further, in this embodiment, since the reflection surface 150a is formed by applying a reflection coating to the glass which is the dustproof member 150, a highly accurate reflection surface can be obtained as in a normal mirror.

In the above-described embodiment, the reflection coating 150a is applied to a part of the dustproof member 150 in order to reflect the light on the dustproof member 150. However, another reflective member may be bonded to the dustproof member. You may do it. That is, as shown in FIG. 5, a reflecting member 165b may be bonded to a part of the light transmitting portion 165a of the dustproof member 165.
As the reflecting member 165b to be bonded, a brilliant aluminum plate or the like used for a reflector or the like of a scanner may be used.
By the adhered reflecting member 165b, light for setting the writing start timing for each scan is reflected on the surface of the reflecting member 165b of the dustproof member 165, as in the above-described embodiment.
Returning to the turning mirror 104 again, the turning mirror 10
4 and is guided to the light detection means 152. On the other hand, light for scanning the photoconductor 105 passes through the light transmitting portion 165a of the dustproof member 165 as it is.

[0025]

As described above, according to the laser scanning device of the present invention, it is not necessary to arrange a dedicated mirror for guiding light to the light detecting means in the optical unit, and the layout flexibility of the optical unit is wide. Become. In addition, it is possible to suppress an increase in component and assembly costs associated with the dedicated mirror, and to reduce costs.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of an image forming apparatus to which a laser scanning device according to an embodiment of the present invention is applied.

FIG. 2 is an enlarged sectional view around a dustproof member.

FIG. 3A is a plan view of an optical system constituting a laser scanning device according to an embodiment of the present invention, and FIG. 3B is a side view of the optical system of FIG.

4A is a lateral side view of the dustproof member, FIG. 4B is a plan view of the dustproof member, and FIG. 4C is a vertical side view of the dustproof member.

FIG. 5A is a lateral side view of a dustproof member according to a modification,
(B) is a plan view of a dustproof member according to a modification, and (c) is a longitudinal side view of a dustproof member according to a modification.

FIG. 6 is a perspective view schematically showing a configuration of a conventional laser scanning device.

[Explanation of symbols]

 102 polygon mirror (light deflecting means) 103 fθ lens (imaging optical system) 105 photoreceptor (scanned surface) 150, 165 dustproof member 150a, 165b reflection surface

Claims (3)

[Claims] 1. A laser scanning apparatus for deflecting a laser beam from a laser unit by a light deflecting unit and condensing a light spot on a surface to be scanned by an imaging optical system to perform optical scanning. A dust-proof member provided at a laser light emission opening of the built-in apparatus main body for preventing dust from penetrating into the apparatus main body while transmitting the laser light; And a light detecting means for receiving a part of the laser beam deflected by the means, wherein a reflecting surface is provided on a part of the dustproof member, and the light reflected by the reflecting surface is guided to the light detecting means. A laser scanning device, characterized in that: 2. The laser scanning device according to claim 1, wherein the reflection surface of the dustproof member is formed by applying a reflective coating to the surface of the dustproof member. 3. The laser scanning device according to claim 1, wherein the reflection surface of the dust-proof member is formed by bonding the reflection member to the dust-proof member.