JPS5944071A - Dimming device of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To photodetect light at plural positions including at the nearly center part of a fluorescent lamp and find the sum, and to control the quantity of light of the fluorescent lamp with fidelity by constituting a lamp housing so that it shakes around the lengthwise axis of the fluorescent lamp, fitting photodetection opening parts for optical fiber to the lengthwise center part and other places, and putting the opposite-side terminals of the optical fibers together and providing a photodetecting elements thereto. CONSTITUTION:When a motor 22 rotates except in a copy cycle, the lamp housing 12 shakes around the lengthwise axis 41 at some angle through a line 13. The size of the link 13 and the fitting positions of the photodetection opening parts 8A-8C for the optical fibers 9A-9C are so set that the photodetection opening parts 8A-8C reach the light irradiation area during exposure, and consequently light used actually for the exposure is transmitted through the optical fibers 8A-8C, an optical multiplexer 10, and an optical fiber to a photodetecting element 26, thereby detecting it as an electric signal output corresponding to the composite quantity of light. Electric power supplied to the fluorescent lamp 1 is controlled by said output to adjust its quantity of light to a specific value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light control device for an electronic copying machine, and particularly to a light control device for controlling the light amount of an exposure fluorescent lamp used to expose a document to a predetermined value. , relates to a light control device for an electronic copying machine.

The amount of light emitted from the exposure fluorescent lamp of an electronic copying machine becomes uneven due to various factors such as changes in environmental temperature and changes over time.
As a result, the image quality of copies is adversely affected. In order to prevent this, conventionally, a light-receiving water droplet was provided to detect unevenness in the amount of light from the fluorescent lamp, and this was fed back to control the amount of light to be constant.

FIG. 1 is a schematic cross-sectional view showing the positional relationship between a fluorescent lamp that generates light to irradiate a document and a light receiving element that detects the amount of light in a conventional apparatus. In the figure, a fluorescent lamp 1 is covered by a lamp housing 2 having an opening (averte 17) in a portion thereof.

Light 3 from the fluorescent lamp 1, the irradiation range of which is defined by the frontage of the lamp housing 2, irradiates the document 5. The light emitted from the opening of the lamp housing 2 is divided into a central portion 3a which is actually used for exposure, and portions 31 on both sides thereof which are not used for exposure.

Both it not used for the exposure! A light receiving element 6 is arranged at a position to receive the light 3b of the i portion, and its detection output is inputted to the light quantity control circuit 20 of the fluorescent lamp 1 through a lead wire 7.

In this manner, in the conventional device, the light receiving element G for detecting the light amount of the fluorescent lamp 1 receives and detects the light 3b on both sides, which is not actually used for exposure, and the output of the light receiving element G detects the light intensity of the fluorescent lamp 1. The power supplied to the light lamp 71\ was controlled by feedback.

For this reason, the above-mentioned light control device cannot faithfully detect the light actually used, and therefore,
There was also a drawback that the light m of the fluorescent lamp 1 could not be controlled accurately.

FIG. 2 is a schematic perspective view showing the positional relationship among a fluorescent lamp, a document, and a light receiving element in another conventional example. In the figure, the same reference numerals as in FIG. 1 represent the same or equivalent parts.

A light receiving element 16 is arranged near the longitudinal end of the fluorescent lamp 1 .

However, in general, although the light intensity of the fluorescent lamp 1 is relatively stable at the center, the light U deteriorates and fluctuates significantly at both ends, so the adjustment as shown in FIG. The optical device also has a drawback in that it cannot accurately detect changes in the overall light amount of the fluorescent lamp 1.

Furthermore, in both FIG. 1 and FIG. 2, the light-receiving surfaces of the light-receiving elements 6 and 16, which convert light energy into electrical signals, were exposed to toner scattering. Another drawback is that floating Ml-ner and dust adhere to the surface, making it impossible to accurately detect the exposure amount.

An object of the present invention is to eliminate the above-mentioned drawbacks, and to accurately detect the sum of the light amount of the approximately central portion in the longitudinal direction actually used for exposure and other portions of the light emitted from the fluorescent lamp.
It is an object of the present invention to provide a light control device for an electronic copying machine, which controls the amount of light from the fluorescent lamp based on this.

In order to achieve the above object, the present invention provides a structure in which a lamp housing of a fluorescent lamp is configured to be swingable around a longitudinal axis of the fluorescent lamp, and a lamp housing of a fluorescent lamp is configured to be swingable about a longitudinal axis of the fluorescent lamp, By attaching the light receiving ports of a plurality of optical fibers to the center and other locations, gathering the opposite sides of the optical fibers and providing a light receiving element thereto, and swinging the lamp housing, the most stable amount of light can be achieved. By receiving light from multiple locations, including the approximate center of a fluorescent lamp with good quality, and from the area where the document is actually illuminated, and calculating the sum of these lights, we can obtain a fluorescent light that is one step more faithful to the actual exposure. The feature is that the light amount of the light lamp is controlled.

FIG. 3 is a schematic perspective view showing the main parts of the first embodiment of the present invention;
Figure 4 is a schematic cross-sectional view of the part where the optical fiber is installed;
FIG. 5 is a schematic side view showing the main parts of the first embodiment.

As is clear from each figure, the fluorescent lamp 1 has a document irradiation area Ja
lamp housing 1 having a narrow opening for
covered by 2. Light receiving ports 8A to 8C of three optical fibers 9A to 9C are attached to substantially the center in the longitudinal direction of the lamp housing 12 and on both sides thereof.

Each of the light receiving ports 8A to 8G of the optical fibers 9A to 9C
The opposite side is connected to the photosynthesizer 10.

A light receiving element 26 is connected to the output side of the light combiner 10 via an optical fiber 21. The output of the light receiving element 26 is supplied to a detection signal amplifier 27 via a lead wire 7. The lamp housing 12 is configured to be swingable about its longitudinal axis by a motor 22 via a link 13.

Roughly speaking, near the opening of the lamp housing 12,
A sponge-like heat insulating member 11 is attached to fill the space between this and the fluorescent lamp 1. Please note that the drawing is M
For simplicity, the heat insulating member 11 is omitted in FIG. 3.

When the motor 22 rotates at times other than the copy cycle, the lamp housing 1 is
2 swings at an angle about a longitudinal axis 41.

When the lamp housing 12 swings, the optical fiber 9A
The dimensions of the link 13 and the mounting positions of the light receiving ports 8A to 8C are set so that the light receiving ports 8A to 8C of 9C reach the light irradiation area during exposure. When the lamp housing 12 swings within the above angle range, the light actually used for exposure is transmitted to the light receiving element 26 via the optical fibers 8A to 8C, the light combiner 10, and the optical fiber 21, as shown in FIG. This makes it possible to transmit the light to the light source and detect it as an electrical signal output according to the combined light amount.

FIG. 6 is a block diagram of a first embodiment of the present invention.

In the figure, when light emitted from a fluorescent lamp 1 hits a light receiving element 26 via a plurality of optical fibers 9A to 9G, a light combiner 10, and an optical fiber 21, the electric signal output increases depending on the combined light amount. The intensity changes. The output of the light receiving element 26 is amplified by a detection signal amplifier 27, and its output signal a is input to a comparator circuit 29, where the reference signal (
voltage) b.

The comparison circuit 29 outputs a difference signal C according to the difference between the two signals @a and b. The difference signal C is input to the phase signal generation circuit 30.

The phase signal generating circuit 30 generates and outputs trigger signals d of different phases based on the magnitude of the differential signal @C. The i/rega signal d output from the phase signal generation circuit 30 is applied to a switching circuit 3 such as a thyristor.
1. Change the delay angle.

As a result, the phase of the current that begins to be supplied to the fluorescent lamp 1 is changed and the power supplied to said fluorescent lamp 1 is controlled. As a result, the light amount of the fluorescent lamp 1 reaches the predetermined value! It will be arranged.

FIG. 7 is a schematic partially sectional perspective view showing the main parts of a second embodiment of the present invention. In the figure, the same reference numerals as in FIG. 3 represent the same or equivalent parts.

Light receiving port 8A-8 of each optical fiber 9A to 9C
The opposite end of the light receiving element 36 is collected in a closed case 15 and arranged so that the light is focused on a light receiving element 36 placed at an appropriate position inside the case 15.

The output of the light receiving element 36 is supplied to a detection signal amplifier 27 via a lead wire 7.

Hereinafter, regarding the first embodiment, the light amount of the fluorescent lamp 1 is adjusted to a predetermined value by performing the circuit operation as described with reference to FIG. A light receiving element is provided at the opposite end of each of the optical fibers 9A to 9C, and the optical output of each optical fiber is individually converted into an electrical signal output, and then these electrical signal outputs are crimped or averaged to obtain the It will be clear that the value may be used as the photodetection signal.

In these embodiments, the aforementioned light receiving elements 26, 36
As the material, a normal photoelectric conversion element, amorphous silicon, etc. can be used.

In the first and second embodiments, the heat insulating member 11 is attached near the opening of the lamp housing 12, so that each of the light receiving openings 8A to 8 of the optical fibers 9A to 9C
It is possible to prevent dust and floating toner from adhering to C.

As a result, the amount of light from the fluorescent lamp 1 can be accurately measured.

Further, when the lamp housing 12 swings, the heat insulating member 11 wipes and cleans the surface of the fluorescent lamp 1 that emits light used for exposure, that is, the surface on the side of the irradiation area. It also removes the adhesion of floating toner and prevents a decrease in the amount of light caused by these.

In the above case, a sponge-like material is used to prevent dust and floating toner from adhering to the light receiving ports 8A to 8C of the optical fibers 9A to 9C, and to clean the surface of the fluorescent lamp 1. Although the heat insulating member 11 is provided in the lamp housing 12, it is of course not necessary to provide this heat insulating member 11.

As mentioned above, in the present invention, one end of a plurality of optical fibers is gathered together, and the other end of a plurality of optical fibers, in other words, each light receiving opening, is connected to a lamp housing of an exposure lamp. The lamp housing is configured to be able to swing around the longitudinal axis of the exposure lamp, and the amount of light actually used for exposure is controlled by the plurality of light beams. Can be done via fiber.

2. By detecting the sum of the amount of light at approximately the center of the lamp and other parts, it is possible to control the light W of the fluorescent lamp more faithfully to the actual exposure.

3. Since each of the light receiving ports of the plurality of optical fibers attached to the lamp housing can be directed downward, the amount of floating toner and dust adhering to each of the light receiving ports can be reduced.

4. If, for example, a sponge-like insulating material is provided near the opening of the lamp housing, when the lamp housing swings, it will automatically close the surface of the lamp that emits light that is actually used for exposure. Since the portion is cleaned and 1-ner and dust attached to the surface are removed, a decrease in the light m can be prevented.

5. By using an optical fiber, it is possible to move the light receiving element away from the fluorescent lamp, so that it is not affected by the heat generated by the fluorescent lamp.

6. By using an optical fiber, the wiring between the light-receiving element and the control circuit can be made clear, thereby eliminating noise caused by electrostatic induction in the wiring and malfunctions caused by this.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view showing the positional relationship between a fluorescent lamp that irradiates an original in a conventional device and a light receiving element that detects the amount of the irradiated light, and Fig. 2 shows a fluorescent lamp and an original in another conventional device. OJ: A schematic perspective view showing the positional relationship of light-receiving elements that detect the amount of light emitted from a fluorescent lamp. Fig. 3 is a schematic perspective view showing the main parts of the first embodiment of the present invention. Fig. 4 5 is a schematic side view of the first embodiment without showing essential parts; FIG. 6 is a block diagram of the first embodiment of the present invention; and FIG. FIG. 2 is a schematic partial cross-sectional perspective view showing essential parts of a second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Fluorescent lamp, 9A-9C, 21... Optical fiber, 12... Lamp housing, 13... Link,
22...Motor, 26.36...Light receiving element agent
Patent attorney Michihito Hiraki (1 person) Fig. 1 5 Fig. 2 Fig. 3 Off view

Claims (1)

[Claims] (1) Adjustment of an electronic copying machine in which the amount of light from the light source for exposure is detected by a light receiving element, and the power supplied to the light source for exposure is controlled so as to obtain the optimum amount of exposure based on the detected amount of light. An optical device in which an exposure lamp is housed, and an opening defining an irradiation area for a document is provided in the axial direction of the device.
A lamp housing is provided with a light-receiving port attached thereto substantially at the center thereof and at other locations along the axial direction of the lamp housing. , the other ends of which are gathered together, comprising a small number of optical fibers provided with light-receiving water droplets, and means for pushing the lamp housing, when the lamp housing is swung, each of the optical fibers A light control device for an electronic copying machine, characterized in that a light receiving opening is located within the document irradiation area, and the output of the light receiving element at that time is used as the detected light amount.