JPH0353407Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a light source device for exposure.
For example, in an exposure light source device used in a copying machine that uses a slit exposure illumination method, a rod-shaped light bulb has a light-emitting unit inside a long rod-shaped envelope tube 1, as shown in FIG. A rod-shaped light bulb with both ends sealed is known, in which a long filament 2 in which light emitting parts 3 and non-light emitting parts 4 are arranged alternately is arranged to obtain a predetermined light distribution characteristic. In a rod-shaped light bulb with this structure, in order to accurately obtain the desired light distribution characteristics, the spacing between the light emitting parts is of course important, but the long filament is placed in the center of the envelope tube in an accurate straight line along the axis. It needs to be arranged in the same way.

By the way, in the above-mentioned method for manufacturing a long filament, first, the entire filament is wound around a metal round rod (mandrel) having a predetermined outer diameter with a dense pitch of the light emitting part, and then the part of the filament in the dense pitch is wound. A non-light-emitting part is formed by winding the metal rod around a round metal rod and stretching it into a substantially straight line. For this reason, the filament in the non-light-emitting part is not in a straight line that coincides with the axis of the light-emitting part, but in the form of a coil with a very loose pitch. Particularly, as shown in FIG. 3, the outermost non-light-emitting part 4a is used as an internal lead wire, and since it is a free end when the filament 2 is alone, the angle may change when it is stretched and formed. Easy to attach. Since the length of the outermost non-light-emitting portion 4a is about 7 mm, if the base end is angled, its tip will deviate considerably from the axis of the filament 2. For this reason, when the tip is fixed to the molybdenum foil 5 by spot welding or the like, it may end up being fixed to the periphery of the molybdenum foil 5. Furthermore, when the both ends of the sealing body 1 are crimped to form the crimped sealing part 11, the substantially linear non-light emitting part 4a may move due to the crimping pressure. Due to these circumstances, the position of the filament within the envelope 1 varies in the tube diameter direction, and in electronic copying machines that employ the slit exposure illumination method, the position of the filament within the envelope 1 is particularly variable near the end of the exposure light source device. There is a problem that the optical characteristics may be distorted. Furthermore, during molding of the crimp-sealing part 11, a large amount of melting heat is transferred to the light-emitting part 3 through the substantially linear non-light-emitting part 4a, and this heat changes the pitch of the coil, resulting in poor light-emitting performance. There was a problem that caused the performance to drop.

Therefore, the present invention has developed a rod-shaped light bulb that has stable light distribution characteristics because the variation in the filament tube diameter direction is small, especially in the vicinity of the end of the exposure light source device, and the light emitting part is less susceptible to heat effects during the formation of the crimp-sealed part. The object of the present invention is to provide a rod-shaped light bulb with both ends sealed, in which a long filament in which light-emitting parts and non-light-emitting parts are arranged alternately is arranged in a long rod-shaped sealed tube. The outermost non-light-emitting part is made of the same wire as the light-emitting part, and has a coiled part wound at a loose pitch with the same inner diameter as the light-emitting part, and a substantially straight line formed by stretching this coiled part. The tip of the substantially straight part is fixed to the molybdenum foil, and
It is characterized by the use of a rod-shaped light bulb with one end of a coil-shaped part buried in a crimp-sealed part.

The present invention will be specifically described below based on embodiments shown in the drawings.

The drawing shows an example of a rod-shaped light bulb used as a light bulb for an exposure light source device of a copying machine, and the sealed tube 1 has an outer diameter of about 8 mm and an inner diameter of about 6 mm.
It is a transparent rod-shaped body with a length of about 330 mm. A long filament 2 is arranged in the envelope tube 1 along its axial direction, and the filament 2 has light emitting parts 3 and non-light emitting parts 4 arranged alternately. Here, the length of the light emitting part 3 is 8.5 mm, and the pitch is
It is a dense coil of 0.19 mm, and the interval between the light emitting parts 3, 3, ie, the length of the non-light emitting part 4, is determined so as to obtain a predetermined light distribution characteristic. As shown in FIG. 1, the outermost light emitting part 3 has a length of 3 mm.
A loosely pitched coiled part 41 with a pitch of 1.0 is formed, but the inner diameter of the coiled part 41 is smaller than that of the light emitting part 3.
equal to the inner diameter of In other words, the coiled part 41 is wound at the pitch described above, following the light emitting part 3, on the metal round bar around which the light emitting part 3 is wound. Then, on the outside of the coiled part 41, a length of 3.5 mm is placed.
Although a substantially straight portion 42 with a pitch of 3.0 is formed,
This is a coiled portion 41 that is extended into a substantially straight line. This coiled part 41 and the substantially straight part 4
2 corresponds to the conventional outermost non-light-emitting portion 4a used as an internal lead wire. The tip of this substantially linear portion 42 is fixed to the molybdenum foil 5 by means such as spot welding, and the tip of the external lead wire 6 is also fixed to the molybdenum foil 5. This molybdenum foil 5 is sealed in the crimp sealing part 11, and at this time, one end of the coiled part 41 is also fixed at the same time. The length of the coiled portion 41 is 3 mm, but it is fixed to a maximum of 2 mm, and at least 1 mm is positioned within the envelope tube 1.

In this way, the outermost light emitting part 3 and the substantially linear part 42
Since a loosely pitched coiled portion 41 is formed between the two, the length of the substantially linear portion 42 is shorter than the conventional outermost non-light emitting portion 4a. Therefore, when the substantially linear portion 42 is stretched and formed, even if the proximal end is angled, the radial deviation amount at the tip is small due to its short length, and the molybdenum foil 5 is It can be fixed in the center. In addition, since one end of the coiled part 41 is fixed at the same time, the coiled part 41 is difficult to move during sealing because it has a larger diameter than a straight one, and it is possible to seal the coiled part 41 at the correct center position. I can do it. Therefore, variations in the filament diameter direction are reduced, and predetermined light distribution characteristics can be accurately obtained. Furthermore, since the space between the sealing part 11 and the light emitting part 3 is coiled, the wire length is long;
Since the melting heat at the time of sealing is attenuated and transmitted, the light emitting part 3 is less subject to thermal expansion, the pitch of the coil does not change, and the light emitting characteristics do not deteriorate.
Therefore, if the rod-shaped light bulb of the present invention is used as a light bulb for an exposure light source device of a copying machine, high-quality images can be copied without uneven light distribution, especially near the ends.

As explained above, the present invention forms, in the outermost non-light-emitting part, a loosely pitched coiled part that follows the light-emitting part using the same wire as the light-emitting part, and a substantially linear part that follows this coiled part. Since it is fixed to the molybdenum foil and one end of the coiled part is buried in the crimp-sealed part, according to the present invention, the variation in the radial direction of the filament is small, especially near the end of the exposure light source device. Moreover, since the light emitting part is not easily affected by heat during the formation of the crimp-sealed part, there is an advantage that the light distribution characteristics are stabilized because there is no sagging in the pitch. In addition, the loosely pitched coiled portion can be formed by winding the light emitting portion on the round metal bar around which the light emitting portion is wound, following the light emitting portion, so it can be formed very easily.

[Brief explanation of the drawing]

FIG. 1 is an enlarged front view of the main parts of a rod-shaped light bulb, FIG. 2 is a front view of the stick-shaped light bulb, and FIG. 3 is an enlarged front view of the main parts of FIG. 2. DESCRIPTION OF SYMBOLS 1... Sealing tube, 11... Crimp sealing part, 2... Filament, 3... Light emitting part, 4... Non-light emitting part, 4
a... Outermost non-light emitting part, 41... Loosely pitched coiled part, 42... Substantially straight part, 5... Molybdenum foil, 6... External lead wire.

Claims (1)

[Scope of utility model registration request] A light source device for exposure of an electronic copying machine that uses the slit exposure illumination method is a double-end sealed type in which a long filament with light-emitting parts and non-light-emitting parts arranged alternately is arranged inside a long rod-shaped sealed tube. In this rod-shaped light bulb, the outermost non-light-emitting part is made of the same wire as the light-emitting part, and has the same inner diameter as the light-emitting part and is wound with a loose pitch, and a coiled part is stretched out. An exposure device characterized by incorporating a rod-shaped light bulb consisting of a formed substantially straight part, the tip of the substantially straight part fixed to a molybdenum foil, and one end of the coiled part buried in a crimp-sealed part. light source device.