JPS5932821A - Device for detecting quantity of light of lamp - Google Patents

Abstract

PURPOSE:To control the quantity of light of a copying machine and the like accurately, by separating a space, wherein a light receiving end surface of an optical fiber provided in an attachment is provided, from another lighted space, thereby preventing the contamination of the light receiving surface of the optical fiber due to particle dust. CONSTITUTION:A converging mirror 1 is provided so as to cover the semicircle of an exposure lamp 2. A screw hole 8 is provided at the central part of the mirror 2. The cross section of the screw hole 8 is of a circular cylinder shape. At the lower end part, a contact edge 9 is provided. At the upper part, an attachment 11 is screwed. The contact edge 9 is closely contacted to the outer surface of the exposure lamp 2. The light receiving end surface of an optical fiber 4 is enclosed in the attachment 11. The space having the light receiving end surface of the optical fiber 4 is separated from the lighted space between the exposure lamp 2 and the conerging mirror 1. With respect to the operating state, the light signal of the exposure lamp 2 is received by the light receiving end surface of the optical fiber 4 and transmitted to a photoelectric transducer circuit. Said light signal is detected by the photoelectric transducer circuit. The detected signal is transduced into an electric signal and sent to a control circuit. The signal is rocessed in the control circuit, and a lamp power source circuit is controlled. The quantity of the light of the exposure lamp is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light amount detection device for an exposure lamp of a copying machine, an optical character reading device, etc.

It goes without saying that fluctuations or reductions in the light intensity of the exposure illumination lamp of optical character reading devices, etc., have a significant relationship with the image quality of the final copy and character reading accuracy, etc. As shown in the schematic layout diagram in Figure 1,
Inside the machine (not shown), one end of an optical fiber 4 is provided near the photometric area 3 of the exposure lamp 2, which is covered approximately half its circumference by a condensing mirror 1, and the other end of the optical fiber 4 is connected to a photoelectric conversion circuit. 5, this photoelectric conversion circuit 5 is connected to a control circuit 6, and the control circuit 6 is connected to a lamp power supply circuit 7 to receive the optical signal of the exposure lamp 2 and the power of the photoelectric conversion circuit 5 via the optical fiber 4. The element detects it, converts it into an electrical signal, and sends it to the control circuit 6, where it is averaged. If the level differs from the set value, the lamp power supply circuit 7 is controlled to adjust the amount of light emitted by the exposure lamp. It was structured like this.

However, as shown in the side cross-sectional view of FIG.
It was common practice to place the light-receiving end face of the optical fiber 4 that transmits data to a suitable space between the exposure lamp 2 and the condensing mirror 1, so the light-receiving end face of the optical fiber was In the case of optical character reading devices, floating objects such as toner may adhere, and in the case of optical character reading devices, paper dust and other fine particles may adhere, reducing the accuracy of detecting the amount of light. In order to prevent this, the operator has to periodically clean the light-receiving end face of the optical fiber 4.

The present invention has been made in order to eliminate the drawbacks of conventional copying machines and optical character reading devices as described above. By fitting the end of this attachment closely to the outer periphery of the exposure lamp, a space having a light-receiving end face of an optical fiber installed in the attachment is separated from other illumination spaces.
The purpose of the present invention is to provide a lamp light intensity detection device.

Hereinafter, the present invention will be explained in detail based on drawings showing embodiments.

FIG. 3 is a side sectional view showing one embodiment of the light amount detection device of the present invention, and FIG. 4 is a partially cutaway perspective view of the end thereof. That is, in these figures, the present invention provides a screw hole 8 in the center of the condensing mirror 2 provided so as to cover approximately half the circumference of the exposure lamp 2. A contact edge 9 is provided for the exposure lamp 2 to the photometric portion 3, and an attachment 11 having a screw thread 10 is screwed onto the upper part.
The light receiving end face of the optical fiber 4 is accommodated in this attachment 11, and the space having the light receiving end face of the optical fiber 4 is connected to the exposure lamp 2 and the condensing mirror 1. It is designed to be separated from the proof space between .

The present invention is constructed as described above, and operates in the same manner as the conventional one, in which the optical signal of the exposure lamp 2 is
The light-receiving end face of the optical fiber 4 receives the light and transmits it to the photoelectric conversion circuit 5, which detects this optical signal and converts the detection signal into an electric signal to control the control circuit 7 and adjust the light intensity of the exposure lamp. This is to adjust the

The amount of light emitted by the exposure lamp 2 can be adjusted by measuring the power supply voltage or frequency if the lamp is a fluorescent lamp.
In the case of incandescent lamps such as linear halogen lamps, the voltage can be adjusted within a certain range by raising and lowering the voltage.

The present invention is configured and operates as described above, and since the photometric area 3 of the exposure lamp 2 is separated from other irradiation space by the attachment 11, the optical fiber 4 installed therein is separated from the other irradiation space by the attachment 11. The light-receiving surface of the is no longer contaminated by fine dust such as toner and paper dust, and therefore the amount of light emitted from the lamp can be accurately transmitted to the photoelectric conversion device 5. The light intensity control is also accurate, which has the advantage that high-quality copies can always be obtained, and since the light-receiving surface of the optical fiber 4 is no longer contaminated, there is no need to clean that area, thus reducing the burden on the operator. It also has the advantage of being able to

It should be noted that the present invention is not limited to the above-mentioned embodiments, and for example, the attachment 11 may be attached to the condensing mirror 1 by fitting in addition to the screwing method described above. It goes without saying that the attachment 11 may be made integrally with the optical fiber 4 from the beginning, and the shape of the attachment 11 does not have to be cylindrical.
The light-receiving end face of the exposure lamp 2 may be directly brought into close contact with the photometric portion 3 of the exposure lamp 2.

[Brief explanation of drawings]

FIG. 1 is a schematic layout diagram of a conventional lamp light amount detection device, FIG. 2 is a side sectional view of the light amount receiving section, and FIG. 3 is a side sectional view showing an embodiment of the lamp light detection device of the present invention. FIG. 4 is a partially cutaway perspective view of the end thereof. 1... Concentrating mirror. 2...Exposure lamp. 3...Photometered part. 4...Optical fiber. 9...Abutting edge. 11・
··attachment.

Claims (1)

[Claims] Attach an attachment whose lower end has a line of contact with the part to be measured of the lamp to any part of the condensing mirror installed to cover approximately half of the lamp, and connect the contact edge of the attachment to the part of the exposure lamp to be measured. A lamp characterized in that the light-receiving end face of the optical fiber is housed in the attachment, and the space that also contains the light-receiving end face of the optical fiber is separated from the illumination space between the lamp and the condensing mirror. Light amount detection device.