Patent Application
20110241516
The present invention relates to an incandescence lamp and an incandescence lamp unit, and, especially relates to an incandescence lamp, which is arranged in a heating roller forming a heating apparatus of a heat roller fixing system or is used as a heat source for the heating roller, and an incandescence lamp unit, in an image forming apparatus, such as a copying machine, a laser printer, or a facsimile, using an electronic photograph method.
Conventionally, an incandescence lamp, which has a filament in an arc tube, is frequently used as a heat source. For example, as described in Japanese Patent Application Publication No. 2001-126846, a halogen heater is used in a fixing apparatus for an image forming apparatus, such as a copying machine, a printer, or a facsimile, wherein the thickness of the lamp is made smaller than that of the conventional glass tube (arc tube), thereby improving the transmittance of light thereof.
Moreover, an incandescence lamp unit, in which two or more incandescence lamps are arranged so as to correspond to the sizes of recording paper sheets, is also known. Japanese Patent Application Publication No. 2009-117147 discloses an example thereof, and
The lamp unit 30 turns on each lamp according to the size of recording paper. For example, in case where the size of recording paper is A4, only the lamp 31 is turned on, and in case where the size of recording paper is A3, both of the lamps 31 and 32 are turned on.
As disclosed in Japanese Patent Application Publication No. 2001-126846, the thickness of the arc tube of the incandescence lamp is made thin, in order to improve the light transmittance thereof. For example, when it is 0.85 mm or less, the strength of the arc tube decreases, so that it is easily damaged, making handling thereof complicated.
In view of the problem of the prior art, it is an object of the present invention to offer an incandescence lamp having a filament in an arc tube thereof and an incandescence lamp unit equipped with two or more incandescence lamps, wherein it is possible to reinforce the strength of the arc tube, thereby making the thickness of the arc tube thin, and to realize improvement of the light transmittance thereof. In order to solve the above problem, an incandescence lamp according to the present invention, comprises a reinforcement rib extending along a tube axis direction on an arc tube, which has a filament inside thereof. Furthermore, two or more incandescence lamps may be provided, each of which is equipped with a filament extending in the tube axis direction within the arc tube, and the filament, which is a light emission part, and an internal lead, which is a non-light emission part, may be provided in each of the lamps. In such an incandescence lamp unit, in which the filaments of the respective lamps are arranged so as to shift from each other in the tube axis direction, a reinforcement rib which extends along the tube axis direction is provided on a portion of the arc tube of the incandescence lamp, corresponding to the internal lead, which is the non-light emission part.
According to the present invention, since the reinforcement rib, which extends along the tube axis direction, is provided on the arc tube thereof, the strength of the arc tube can be reinforced, so that the arc tube can be made thin, which improves the light transmittance. Moreover, in the incandescence lamp unit having two or more incandescence lamps, wherein the positions of the filaments, which are light emission parts of the respective lamps, shift from each other, the reinforcement rib extending along the tube axis direction is provided at a position of the arc tube of each lamp, which corresponds to the internal lead, so that it is possible to transmit light from the light emission part to the outside thereof, without interference, while reinforcing the strength of the arc tube.
Other features and advantages of the present incandescence lamp will be apparent from the ensuing description, taken in conjunction with the accompanying drawings, in which:
Linear reinforcement ribs 6 and 6, which extend along the tube axis direction, are provided on an outer circumferential surface of the arc tube 2.
The number of the reinforcement ribs 6 is chosen depending on the diameter of the arc tube 2, and/or the size of reinforcement ribs 6. In addition, in this case, it is desirable to form the reinforcement ribs 6, so as to avoid the position of an exhaust chip 7 of the arc tube 2.
Although in the above-mentioned embodiment, such a structure in which the reinforcement ribs 6 and 6 are formed on the outer circumferential surface of the arc tube 2, is shown, the structure is not limited thereto. The reinforcement ribs 6 and 6 can be formed on an inner circumference face thereof.
Moreover,
On the other hand, filaments 23 and 24 are arranged in both end sides of an arc tube 22 of the other discharge lamp 21, and are connected to each other by an internal lead 25 located in the central part thereof. These filaments 23 and 24 are disposed at the positions which respectively correspond to the internal leads 14 and 15 of the one lamp 11, and the internal lead 25 is disposed at the position, which corresponds to the filament 13 of the one of lamps 11. And the spiral reinforcement rib 26 is formed at the position, which corresponds to the internal lead 25, which is located at the central part, on the outer circumferential surface of the arc tube 22, and no reinforcement rib is formed at the positions, which correspond to the filaments 23 and 24 in the both end sides thereof.
In addition, although
As mentioned above, the strength of the arc tube can be reinforced in the incandescence lamp according to the present invention by forming the reinforcement ribs extending along the tube axis direction in the arc tube having a filament, and it is possible to make the arc tube thin, thereby improving the light transmittance thereof. Moreover, in the incandescence lamp unit having two or more incandescence lamps, in which the positions of the filaments, which are light emission parts of the respective incandescence lamps, are shifted from one another, the reinforcement rib extending along the direction of the tube axis is provided on a position of the arc tube of each lamp, which corresponds to the internal lead. Therefore, while the strength of the arc tube is reinforced, since no reinforcement rib is formed in the position corresponding to each filament, light from the filament is emitted to the outside thereof without interference of the reinforcement rib.
The preceding description has been presented only to illustrate and describe exemplary embodiments of the present incandescence lamp. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. It will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. The invention may be practiced otherwise than is specifically explained and illustrated without departing from its spirit or scope.
