JPS62204221A - Photodetecting device - Google Patents

Abstract

PURPOSE:To adjust rapidly and accurately the position of a photodetector by providing the titled device with a light guiding means for guiding the optical path of a light beam in a prescribed direction, a detecting means and a supporting means for unitedly supporting both the means. CONSTITUTION:When the titled device is applied to an optical system for a laser beam printer (L.B.P), the device is provided with the supporting mean 13 capable of being moved and adjusted to unitedly support a reflecting mirror 6 and a photodetector 7. Since the L.B.P forms the latent image of a recording image on a photosensitive drum 5 by scanning and modulating a scanning light beam 10, the starting point of the recording signal can be determined by receiving and detecting the scanning light beam by the photodetector 7 every scanning, Since the reflecting mirror 6 and the photodetector 7 are unitedly arranged on the supporting member 13, only the supporting member 13 to be moved is finely adjusted so that the prescribed quantity of light can be received by a photodetecting element in the photodetector 7, so that rapid and accurate adjustment can be attained.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is applicable to a photodetection device, particularly an optical device such as a laser beam printer, in which a part of an irradiated light beam is detected and the light beam is modulated. The present invention relates to a photodetecting device used.

<Prior art> ゛Conventionally, laser beam printers described in E (hereinafter referred to as L, B,
It is written as P. ) and other various optical devices have been commercialized and are now widely used as optical recording and/or reproducing devices and information reading devices. Many devices of this type are generally equipped with a photodetector for correcting variations in the output of the light source and for detecting the intensity of the illumination light flux illuminating the information surface or the intensity of the light flux reflected from the information surface. Examples of such photodetectors include L, B, and P.

The photodetecting device used in this will be explained.

FIG. 1 is a perspective view showing a conventional example of a laser beam printer. The light beam emitted from the semiconductor laser device 1 is focused into a parallel light beam by a collimator lens 2, and is reflected and scanned by the surface of a polygon mirror 3 rotating in the direction of arrow 8 at a constant rotation speed. After the light beam scanned at a constant angular velocity passes through the fθ lens 4, the scanning light beam 10 is condensed onto the surface of the photosensitive drum 5, and is scanned at a constant linear velocity in the direction of the arrow 9, onto the surface of the photosensitive drum. A scanning line 11 is formed. The scanning light beam lO is reflected by the reflection mirror 6 for each scan, and is received by the photodetector 7 placed approximately at the focal position of the fθ lens. The photodetector 7 functions to determine the time point at which the recording signal starts, and a control circuit (not shown) generates a signal for starting the recording signal after a certain period of time from the time of light reception. By this signal, the semiconductor laser 1 is modulated brightly and darkly in accordance with a recording signal from a modulation circuit (not shown), and the photosensitive drum 5 rotates in the direction of arrow 12 to form a latent image of a recorded image.

In the above-mentioned conventional glues B and P, a photodetector such as a bin photodiode is used to detect the fast-scanning light flux with a high response speed, but the size of the photodetector is 0.
．． It is small, about 5 mm square, and in order for the beam to enter the light receiving element correctly, it requires a reflection mirror 6 or 1 and a photodetector 7.
adjustment is necessary. However, in order to accurately guide a part of the scanning light beam to the folded photodetector 7, it is necessary to
The drawback is that it is difficult to maintain and adjust the structure, making the configuration complicated.

The problems of conventional photodetectors have been described using L, B, and P as examples, but these kinds of problems are also common to optical devices such as copying machines. That is, in the conventional photodetection device,
Since the light guide member for guiding part of the light flux to the light receiving element and the light receiving element for detecting the light were arranged separately, a reflective mirror or the like was required to accurately guide the light flux to be detected, such as the scanning light flux, to the light receiving element. At least one of the light guiding member and the light receiving element must be adjusted, and the adjustment is troublesome and time consuming.

<Summary of the Invention> In view of the above-mentioned conventional problems, an object of the present invention is to provide a photodetecting device that can quickly and reliably adjust the position of a photodetector.

In order to achieve the above object, the photodetection device according to the present invention includes:
A device for detecting a part of a luminous flux emitted from a predetermined light source, the apparatus comprising at least a light guide means for changing the optical path of the predetermined luminous flux emitted from the light source and guiding it in a predetermined direction, and at least the light flux guided by the light guide means. A detection means for detecting a part of the light guide means, a support means for integrally supporting the light guide means and the detection means;
It is characterized by having the following.

Further objects and features of the present invention will become clear from the examples given below.

<Embodiment> FIG. 2 shows an embodiment of the photodetection device according to the present invention, which is similar to that described in the section of the prior art.

The case where this is applied to optical systems B and P is shown. In the figure, the same members as those in FIG.

Note that 13 is a support member that integrally supports the reflection mirror 6 and the photodetector 7 and is movable and adjustable. As mentioned above <L, B,
P forms a latent image of a recorded image on the photoreceptor drum 5 by scanning and modulating the scanning light beam 10, and detects the recording signal by receiving and detecting the scanning light beam with the photodetector 7 every scan. Determine the starting point. In this embodiment, by integrally arranging the reflecting mirror 6 and the photodetector 7 on the support member 13, only the movable support member 13 can be finely adjusted so that a predetermined amount of light can be adjusted between the photodetector 7 and the light receiving element. By reaching , quick and accurate adjustment becomes possible. Below, supporting member 1
3 shows a configuration example of a reflecting mirror 6 and a photodetector 7 arranged in FIG.

FIGS. 3(A) and 3(B) show examples of the configuration of a photodetector, in which the same members as in FIG. 2 are designated by the same reference numerals. Further, L is a light beam of the scanning light beam 10 that is incident on the internal reflection mirror 6, and 14 is a support member 13.
15 is the rotation center of the support member 13, 16 is a fixed member such as a beam, a side plate or a stay of B and P, 1
7.18 is a screw for pressing the support member 13 against the fixing member 16, 19 is a plate spring, and 20 is a screw for finally fixing the support member 13 to the fixing member 16. Here, the reflecting mirror 6 and the photodetector 7 are fixed on the support member 13 so that the light beam L incident on the reflecting mirror 6 at a predetermined incident angle is efficiently guided to the photodetector 7. Further, the support member 13 is connected to the screw 17 and the screw 1 via the leaf spring 19 as shown in FIG. 3(A).
8 is in pressure contact with the fixing member 16, and by adjusting the screw 17 and/or the screw 18, the position of the support member 13 can be finely adjusted. That is, as shown in FIG. 3(B), it is possible to rotate in the direction of arrow 14 around a rotation center 15, and this rotation center 15 is approximately at the same height as the reflection surface of the reflection mirror 6, and at the same time as the reflection surface of the reflection mirror 6. It is desirable to place it near the center of the reflective surface.

As described above, the light beam L, which is a part of the scanning light beam, is reflected by the reflection mirror 6.
By adjusting the movement of the support member 13 around the rotation center 15 so that a stable amount of light enters the photodetector 7 and is accurately reflected and deflected, the reflection mirror 6 and the photodetector 7 can be This eliminates the need for individual adjustments, allowing quick and accurate alignment.

FIG. 4 shows another embodiment of the photodetector according to the present invention, the basic configuration of which is the same as that of the previous embodiment.

Therefore, most of the symbols in the figures indicate the same members as in FIG.
21 indicates an optical fiber. That is, in this embodiment, an optical fiber 21 is arranged in place of the photodetector 7,
The light beam incident surface is the scanning light beam (or light beam L) as described above.
) near the focal point. By arranging the end face of the optical fiber 21 at the light detection position in this way, the photodetector linked in advance to one end face (output surface) of the optical fiber 21 can basically be arranged at any position. Therefore, the effect of contributing to the degree of freedom in the configuration of the device is large. In this embodiment as well, the method of attaching the support member 13 and the method of adjusting its movement are the same as those of the previous embodiment, so explanation thereof will be omitted. Also, other optical waveguide means may be used instead of the optical fiber, and the effects of this embodiment can be fully obtained.

As described above, according to the photodetection device according to the present invention, by integrally supporting the light guide means and the photodetection means with the support means, it is possible to perform optical adjustment for detecting the test light beam extremely easily and stably. . This device is especially effective when the light flux to be detected is an extremely thin light beam such as a light beam, as in the above embodiment, and the light receiving element of the light detecting means is equipped with a minute light receiving surface such as a pin photodiode. be.

Furthermore, in the above embodiment, in consideration of the spread of the light beam after reflection by the reflection mirror 6, a condenser lens is disposed between the reflection mirror 6 and the photodetector 7 to direct the light beam to the photodetector 7. It is effective to focus the light on the light receiving surface. It is clear that this condenser lens is also disposed integrally supported on the support member 13. Furthermore, in the optical system of the LBP described above, the light receiving surface of the photodetector 7 is optically equivalent (conjugate) to the photosensitive surface of the photosensitive drum.
If the condenser lens is placed at the position shown in FIG.

Further, in the above-described embodiment, the reflecting mirror 6 is shown as a light guiding means for guiding a part of the light beam emitted from the light source in a predetermined direction, but this light guiding means is not limited to a reflecting member such as the reflecting mirror 6. do not have.

For example, it may be an optical element having refractive power such as a prism or a lens, as long as it can be arranged so as not to substantially obstruct the optical path of the light beam used for recording and reproduction among the light beams emitted from the light source. Furthermore, depending on the configuration of the device in which the present photodetecting device is to be installed, the light guiding means may be formed using a plurality of optical elements such as the reflecting mirror, prism, or lens in the above embodiments.
Many aspects are possible, such as forming a light guiding means by combining a reflecting mirror and a prism, etc., and depending on the arrangement of the light guiding means and light detecting means such as a light receiving element, support means for integrally supporting them can be appropriately used. design.

In addition, in the above embodiment, the position of the support member 13 is adjusted by rotating the support member 13 using an extremely simple method of adjusting the screws 17 and 18. More precise adjustment can be achieved by adding a mechanism that moves the object vertically (within the plane of the paper) or in a direction perpendicular to the plane of the paper. In addition to making the various movement adjustment mechanisms described above manually adjustable using simple members such as screws, it is also possible to use mechanical mechanisms using gears, etc., or electrically using actuators such as piezoelectric elements. It is also effective to control. If the position can be electrically adjusted in this manner, readjustment or fine adjustment can be easily made from the outside even after the present photodetector is incorporated into various optical devices.

The above description has been made based on the case where the present photodetection device is applied to a laser beam printer. However, the light arrival detection device is not limited to this type of optical device, but can be applied to various other optical devices related to recording and reproducing information such as a single image. It goes without saying that this invention is particularly effective for devices that use narrow light beams such as laser beams, such as laser scanning alignment devices, in addition to LBPs, as described above. Furthermore, it is not limited to devices equipped with this type of single light source.
The light detection device can also be applied to devices using a plurality of light sources such as a diode array.

, <Effects of the Invention> As explained above, the photodetection device according to the present invention has the advantage that the light guide means and the detection means are integrally supported by the support means so that the light flux to be detected can be well guided to the detection means. This device makes optical adjustment extremely easy. Therefore, this is an extremely effective photodetection device when the light flux to be detected is a narrow light beam and the light receiving surface of the detection means is small.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a laser beam printer having a conventional photodetector. FIG. 2 is a schematic configuration diagram of a laser beam printer having a photodetection device according to the present invention. FIGS. 3(a) and 3(b) are diagrams showing a method for installing and adjusting a position of a photodetecting device according to the present invention. FIG. 4 is a diagram showing a modification of the photodetecting device according to the present invention. 1 ------- - Semiconductor laser 2 ------- Collimator lens 3 ------- Polygon mirror 4 ------- fθ lens 5 ------- One photosensitive drum 6 ---- --Reflection mirror 7----Photodetector 8---1---Rotation direction of polygon mirror 9------
Scanning direction of one scanning light beam 10------One scanning light beam 11---One scanning line 12---One rotational direction of photosensitive drum 13------
- Support member 14 - - Rotation direction of support member 15 - - Center of rotation of support member 16 - - M - Side plates 17 and 18 of LBP - Screws 19 -------- Rice spring 20 -------- Screw 21 ----- Light guiding fiber

Claims (1)

[Claims] (1) A device for detecting a part of the luminous flux emitted from a light source, which includes a light guide means for changing the optical path of the part of the light flux emitted from the light source and guiding it in a predetermined direction, and the light guide means. A photodetection device comprising a detection means for detecting at least a portion of a light beam, and a support means for integrally supporting the light guide means and the detection means.