JPS60202653A - Device for heating electric-discharge lamp - Google Patents

Abstract

PURPOSE:To enable an electric discharge lamp to be homogeneously heated with rapid rising by fixing a code-like heating member inside a thin metallic envelope by means of a highly thermoconductive adhesive and then attaching the thus formed body around the outer wall of the tube of the lamp except its opening. CONSTITUTION:When heating an electric discharge lamp 1 used as an exposure device for an electronic copier, a heater is prepared by multiply folding a code- like heating member 4 almost at intervals of the length of the tube 1a of the lamp 1 and then fixing the folded body inside an envelope 2 made of a thin metallic film having high thermoconductivity by means of an adhesive 5 such as a silicone resin. After the thus prepared heater is stuck to the outer surface of the tube 1a except its opening by means of an adhesive 3, current is fed to the heating member 4 to perform heating. Therefore it is possible to homogeneously heat the lamp 1 by efficiently conducting the joule heat of the heating member 4. Additionally, it is possible to prevent any contamination of the power source by the noise of the lamp 1 by connecting the envelope 2 to an earth electric potential.

Description

TECHNICAL FIELD The present invention relates to a discharge lamp heating device for heating a discharge lamp used in an exposure device of an electronic copying machine or the like.

Conventional discharge lamp heating devices are known that generate heat by supplying current to a carbon-based heating element, but this method does not allow for a large rise in temperature because the power supplied to the heating element cannot be increased too much. However, the heat distribution is slow (and when the tube diameter of the discharge lamp is small, the heat distribution is very uneven, which causes cracks in the tube).

In addition, there is a known discharge lamp heating device that generates heat by supplying current to a heating element deposited on the tube wall of the discharge lamp, but this method does not allow too much power to be supplied to the heating element. Since the heat generating element cannot be heated, the temperature rises slowly, and processing for connecting the terminal of the heating element to the power supply circuit is difficult.

Furthermore, the above-described discharge lamp heating device has a drawback in that noise generated by the discharge lamp mixes into the conductor that supplies power via the heating element.

Objective One object of the present invention is to increase the power supplied to the heating element, thereby increasing the heat build-up speed, and heating the discharge lamp tube almost uniformly.
It is an object of the present invention to provide a discharge lamp heating device that is easy to process for connecting terminals of a heating element and a power supply circuit.

Other objects of the present invention are that the power supplied to the heating element can be increased, so that the heat rises quickly, the tube of the discharge lamp can be heated almost uniformly, and the terminals of the heating element can be heated almost uniformly. Provided is a discharge lamp heating device which is easy to process for connection with a power supply circuit and which can prevent noise generated by the discharge lamp from entering a conductor that supplies power via a heating element. It's about doing.

Configuration Next, the configuration of the present invention will be explained based on illustrated embodiments.

One embodiment of the invention is shown in FIGS. 1 and 2.

In FIG. 1, the symbol l indicates a discharge lamp.

The outer surface of the metal thin film envelope 2 is adhered to the tube 1a of the discharge lamp 1 except for the opening with an adhesive 3 having good thermal conductivity. The metal thin film enclosure 2 is formed of a metal thin film with good thermal conductivity, such as aluminum foil.

Inside the metal thin film enclosure 2, a cord-shaped heating element 4 is provided.
is installed. The heating element 4 is formed by covering a metal wire wound around a bundle of insulating fibers with an insulating resin having good thermal conductivity. The metal side of this heating element 4 is a nichrome wire,
Copper wire, nickel wire, etc. are used. This heating element 4
As the insulating resin for covering the metal wire, silicone resin or the like is used. The heating element 4 is bent along the length of the tube la of the discharge lamp l and placed inside the metal thin film envelope 2.

The inside of the metal thin film enclosure 2 is filled with an adhesive 5 having good thermal conductivity, and the heating element 4 is fixed to the metal thin film enclosure 2 by this adhesive 5. As the adhesive 5, silicone resin or the like is used.

Both ends of the metal wire of the heating element 4 are connected to a power supply circuit 6. This power supply circuit 6 generates heat by supplying current to the metal wire of the heating element 4, thereby heating the tube 1a of the discharge lamp 1. The Joule heat generated in the metal wire of the heating element 4 is
The light is conducted to the tube 1a of the discharge lamp 1 via the insulating resin covering it, the adhesive 5, the metal thin film envelope 2, and the adhesive 3.

Since the insulating resin, adhesive 5, metal thin film enclosure 2, and adhesive 3 that cover the metal wire of the heating element 4 all have good thermal conductivity, The generated Joule heat is efficiently and evenly distributed in the discharge lamp.
is conducted to the tube 1a.

Another embodiment of the invention is shown in Figure wJ3 and will now be described.

In the embodiment shown in FIG. 3, the metal thin film enclosure 2 is grounded in the discharge lamp heating apparatus shown in FIGS. 1 and 2.

By grounding the metal thin film enclosure 2, the discharge lamp 1
Although the noise generated by the noise enters the metal thin film enclosure 2, this noise can be released without being mixed into the conductor wire of the power supply circuit 6.

When we conducted an experiment to detect noise at the connection between the electronic copying machine and the power supply terminal that supplies power to an electronic copying machine equipped with an exposure lamp having a discharge lamp heating device as shown in Fig. 3, we found that the degree of noise was It was confirmed that it was as shown by characteristic line A in FIG.

Effects According to one aspect of the present invention, it is possible to increase the power supplied to the heating element, so that the heat rises quickly, and the tube of the discharge lamp can be heated almost uniformly, and
Processing for connecting the terminals of the heating element and the power supply circuit is easy.

According to another aspect of the present invention, it is possible to increase the power supplied to the heating element, so that the heat rises quickly, and the tube of the discharge lamp can be heated almost uniformly. Processing for connection between the terminal and the power supply circuit is easy, and noise generated by the discharge lamp can be effectively prevented from entering the conductor that supplies power via the heating element.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing a discharge lamp heating device of the present invention, FIG. 2 is a cross-sectional view showing the same discharge lamp heating device, and FIG. 3 is a cross-sectional view showing another embodiment of the present invention. diagram, and
FIG. 4 is a diagram for explaining the effect of the embodiment shown in FIG. 3. Body, 5...Adhesive, 6...Power circuit

Claims (2)

[Claims] (1) A cord-shaped heating element made of a metal wire wound around a bundle of insulating fibers and coated with an insulating resin with good thermal conductivity is placed inside a metal thin film envelope with good thermal conductivity. Then, the heating element is fixed to the metal thin film enclosure by filling the inside of the metal thin film enclosure with an adhesive having good thermal conductivity, and the outer surface of the metal thin film enclosure is heated to the tube excluding the opening of the discharge lamp. A discharge lamp heating device characterized in that the discharge lamp is heated by bonding with a highly conductive adhesive and supplying current to the metal wire of the heating element to generate heat. (2) A cord-shaped heating element made of a metal wire wound around a bundle of insulating fibers and coated with an insulating resin with good thermal conductivity is placed inside a metal thin film envelope with good thermal conductivity. Then, the heating element is fixed to the metal thin film enclosure by filling the inside of the metal thin film enclosure with an adhesive having good thermal conductivity, and the outer surface of the metal thin film enclosure is heated to the tube excluding the opening of the discharge lamp. Discharge lamp heating characterized in that the discharge lamp is heated by bonding with a highly conductive adhesive, grounding the metal thin film envelope, and supplying current to the metal wire of the heating element to generate heat. Device.