JPS63157102A - Recorder and optical element used for same - Google Patents

Abstract

PURPOSE:To reduce the incident quantity onto a recording medium, of an unnecessary light beam reflected from the surface of an optical element, by forming a part through which the light beam of the surface of the optical element does not transmit through, to a scabrous surface. CONSTITUTION:A part of a non-use area through which the laser light of the surface of a lens 40 does not transmit through is formed to a scabrous surface and becomes a sand surface 40a. By this scabrous surface, light beam which has impinged on the sand surface 40a does not remain a sharp beam but becomes a scattered light scattered in all directions. Accordingly, even if a part of the light beam is reflected by the surface of the lens 40, reflected repeatedly by other part, becomes stray light and reaches on a photosensitive drum, or the reflected light from the photosensitive drum is reflected by the surface of the lens 40, it can be reduced that said light is made incident on the photosensitive drum again, and an image can be recorded satisfactorily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a recording device commonly used as a laser printer, for example, and an optical element used in the recording device.

(Prior art) A laser printer generates a laser beam from a laser generator, reflects it on a rotating polygon mirror, and scans it onto a ram under exposure through a lens (optical element) and mirror to form a latent image. It is supposed to be recorded.

<Problems to be Solved by the Invention> However, in the past, since the surface of the lens 1 was mirror-finished, a portion of the light was reflected on the surface of the lens, becoming stray light and entering the photosensitive drum. However, there is a problem in that the reflected light from the photosensitive drum is reflected on the surface of the lens and enters the photosensitive drum again, which adversely affects the image.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides an apparatus for recording an image by transmitting light through an optical element and scanning it on a recording medium. This device is characterized in that the portion of the surface of the device through which light does not pass is roughened.

(Function) With the above means, the light reflected on the surface of the optical element is turned into scattered light, thereby reducing the amount of unnecessary light incident on the recording medium.

(Example) The present invention will be described below with reference to an example shown in the drawings.

In the figure, reference numeral 21 denotes an apparatus main body 21. A photosensitive drum 32 as a recording medium is provided in the apparatus main body 21 so as to be rotatable in the direction of the arrow. A charger 33, an exposure section 34, a developing device 35, a transfer charger 36, and a static eliminator 37 are arranged in this order.

Reference numeral 39 in the figure is an optical unit provided in the center of the apparatus main body 21, and the optical unit 39 scans the photosensitive drum 32 with a laser beam.

Also, a paper feed cassette 31 is provided at the inner bottom of the apparatus main body 21.
is stored in a removable manner, and the sheets P inside are taken out one by one by the rotation of the sheet feed roller 44. This taken out paper P is sent to registration rollers 46 via a guide 45. The paper P aligned by the registration rollers 46 passes through a guide 47 and a feed roller 48 to a transport path H formed above the photosensitive drum 32.
It is now being sent to. And this conveyance path H
The transfer charger 3 is placed along the conveyance direction of the paper P.
6, a fixing device 51 consisting of a paper guide 54, a heat roller 49 and a press roller 50, and a pair of paper ejection rollers 52
A, 52b, and a static elimination brush 55 are arranged in this order. A paper ejection tray 5 is provided on the ejection side of the paper ejection roller pair 52a, 52b.
3 is provided.

During image formation, the surface of the photosensitive drum 32 is uniformly charged by the charger 33, and a laser beam 60 is scanned onto the charged upper surface of the photosensitive drum 32 by rotation of a polygon mirror 38, which will be described later. A latent image is formed. This D'l latent image is visualized in the developing device 35 by supplying a developer. On the other hand, at this time, the paper P is taken out one by one from the paper feed cassette 31 by the rotation of the paper feed roller 44 and sent to the registration roller 46 via the guide 45. After the paper P is aligned here, it is sent between the photosensitive drum 32 and the transfer charger 36 via the guide 47 and the feed roller 48, and the image is transferred thereto. Then, the paper P on which the image has been transferred is guided by the paper guide 54 and sent to the fixing device 51, where the image is fixed, and then transferred to the paper discharge roller pair 52a.

The paper is discharged onto the paper discharge tray 53 via the paper 52b.

Next, regarding the optical unit 39, FIGS.
This will be explained in detail with reference to the drawings.

In the figure, reference numeral 55 denotes an optical unit main body, and within this optical unit main body 55, a polygon mirror 38 as an optical deflection element that is rotationally driven by a drive motor 38a is provided. A laser beam generated from a laser 63 is scanned. The laser beam 60 reflected from the polygon mirror 38 is transmitted to the first lens (optical element) 40 and the first and second mirrors 41.4 that constitute the optical system K.
2 Furthermore, the photosensitive drum 32 is scanned through a second lens (optical element) 43.

Further, the optical unit main body 55 includes a laser unit 6.
Inside the laser unit 64, there is a semiconductor laser 63 and a collimator lens 6 for converting the diffused laser light emitted from the semiconductor laser 63 into parallel light.
5 is integrally held by a holding member 66.

In addition, the laser beam that has become parallel light through the collimator lens 65 passes through two prisms 67 and 68, as shown in FIG.
As a result, the spot is formed on the photosensitive drum 32 to have an appropriate spot size, and is deflected into the scanning plane.

Further, as the first lens 40, a lens with aspheric surfaces on both sides is used, and as the second lens 43, a lens with an aspheric surface on one side and a toric surface whose generating line is a non-conic curve is used on the other surface. . It is very difficult and expensive to make an aspherical lens from glass, so the first and second
Together with the lenses 40 and 43, they are molded from plastic, which is relatively easy to manufacture, can be mass-produced, and is inexpensive.

The first lens 40 is constructed as shown in FIG. That is, non-holding parts 76 and 76 are integrally provided at both ends of the first lens 4o, and these non-holding parts 76
．． The first lens 4o is held by being pressed and held by the holding members 77a and 77b. The unheld portions 81i76.76 of the first lens 40 are formed along the direction perpendicular to the optical axis of the laser beam, and are held by the holding members 77a and 77b under pressure by a force parallel to the optical axis. ing.

Further, a convex portion 78 is provided on the intermediate upper surface portion of the first lens 40.
is provided, and this convex portion 78 is connected to the optical unit main body 55.
By being fitted into a recess 79 formed in , positioning in the front-rear and left-right directions is performed.

Incidentally, the unused area on the surface of the first lens 40 through which the laser beam does not pass is roughened to form a sandy surface 40a.
It becomes. Due to this roughening, the light hitting the sandy ground 40a does not remain a sharp beam, but becomes scattered light scattered in all directions.

Therefore, even if a part of the light is reflected on the surface of the first lens 40, it may be repeatedly reflected on other parts and reach the photosensitive drum 32 as stray light.
It is possible to reduce the possibility that the reflected light is reflected on the surface of the first lens 4o and enters the photosensitive drum 32 again, and an image can be recorded satisfactorily.

Note that the second lens 43 is also configured in the same manner as the first lens 40, and provides the same effects as described above.

[Effects of the Invention] As explained above, according to the present invention, it is possible to reduce the incidence of unnecessary light reflected from the surface of the optical element onto the recording medium, and it is possible to achieve the effect that images can be recorded satisfactorily. It is something.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic diagram showing a laser printer, FIG. 2 is an internal diagram showing an optical unit, and FIG. 3 is a diagram showing a side lens and its holding member. FIG. 32... Photosensitive drum (image carrier>, 40.43...
First and second lenses (optical elements), 40a... rough surface. Applicant's Representative Patent Attorney Takehiko Suzue Figure 2, Figure 6, Figure 3, Figure 4, Figure 5, Figure 6

Claims (3)

[Claims] (1) A recording device that records an image by transmitting light through an optical element to scan and record an image on a recording medium, characterized in that a portion of the surface of the optical element through which light does not pass is roughened. (2) The recording device according to claim 1, wherein the optical element is molded from a synthetic resin material. (3) An optical element that transmits light and converges or diffuses it, characterized in that a portion of the lens surface of the optical element that does not transmit light is roughened.