JPH0412592Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to flash lamps used as light sources or heat sources in copying machines such as electrophotographic copying machines, printers, and other equipment, and is particularly aimed at preventing ignition errors. This relates to a prevented flash lamp.

[Background of the idea]

In recent years, flash lamps have come to be used as exposure light sources in copying machines such as electrophotographic copying machines because they can expose an entire large area at once and achieve rapid exposure. It's coming.

In a flash lamp used as such an exposure light source, the distance between the electrodes is relatively large to obtain a sufficient exposure width, and therefore the dielectric breakdown voltage between the electrodes is generally high. For this reason, a trigger electrode made of metal wire is usually installed on the outer wall of the arc tube between the electrodes, and a high trigger voltage is applied to this trigger electrode to prevent the flash lamp from igniting. The required interelectrode voltage is lowered to lighten the voltage burden on the power supply circuit.

However, when a flash lamp fires, a considerable amount of light energy is emitted, although momentarily, so the trigger electrode repeatedly expands and contracts thermally each time the flash lamp fires. As a result, there is a risk that the trigger electrode may rise from the outer wall of the arc tube, resulting in ignition errors.

For this reason, the present inventor first developed a linear trigger electrode with one end fixed and the other free end, and an arc tube shaft fixed at at least one point of the trigger electrode. proposed a flash lamp in which a trigger electrode assembly is disposed on the outer wall of the arc tube and includes a holding member that extends in an arc over more than half the circumference of the arc tube so as to be movable in the direction of the arc tube. No. 60-60399).

[Problem that the invention attempts to solve]

However, in flash lamps used as light sources for exposure in electrophotographic copying machines, etc., the voltage applied between the discharge electrodes is quite high, and when firing, a high-frequency trigger is applied to the trigger electrode to cause dielectric breakdown between the electrodes. In order to supply high voltage for triggering, it is necessary to sufficiently insulate the voltage applied between the discharge electrodes and the high voltage for triggering. For this reason, a means to improve the insulation performance by supplying the high voltage for the trigger to the trigger electrode from the center of the arc tube instead of from the end of the arc tube has been studied. A method has been proposed in which a tongue piece for supplying high voltage for triggering is connected to a portion located in the center of the tube, and a contact type power supply terminal such as a brush is brought into contact with this tongue piece to supply high voltage for triggering.

However, in a flash lamp equipped with a trigger electrode assembly as described above, when the flash lamp fires, the trigger electrode expands and contracts, thereby causing the tongue to move in the axial direction of the arc tube.
As a result, there is a problem in that poor contact with a contact type power supply terminal such as a brush is caused, and ignition errors occur.

[Purpose of invention]

The present invention was developed based on the above-mentioned circumstances, and its purpose is to prevent displacement of the contact position of the trigger electrode assembly with the contact type power supply terminal due to thermal expansion and contraction of the trigger electrode. As a result, it is an object of the present invention to provide a flash lamp that can always reliably supply a triggering high voltage to a trigger electrode through a contact type power supply terminal and that prevents ignition errors.

[Means for solving problems]

A high-input flash lamp that prevents ignition errors according to the present invention is a flash lamp comprising an arc tube and a trigger electrode assembly disposed on the outer wall of the arc tube, the trigger electrode assembly comprising: A linear trigger electrode extends on the outer wall of the light emitting tube along the axial direction of the light emitting tube, and a trigger electrode is fixedly provided at one end and the other end of the trigger electrode and is movable in the axial direction of the light emitting tube. An arc-shaped holding member held under pressure on the outer wall of the arc tube, and a metal fixing member connected and fixed to the trigger electrode and fixed at the center in the longitudinal direction of the arc tube. The high voltage for triggering is supplied by a contact type power supply terminal arranged in contact with the fixing member.

[Effect]

According to this configuration, since the metal fixing member is connected and fixed to the trigger electrode and the fixing member is fixed at the center of the arc tube in the longitudinal direction,
The position of the fixed member is prevented from shifting due to thermal expansion and contraction of the trigger electrode. Therefore, when a high voltage for triggering is supplied by a contact type power supply terminal placed in contact with this fixed member, the position of the fixed member is prevented. This does not cause displacement, and as a result, it is possible to prevent poor contact with the contact type power supply terminal, and it is possible to reliably supply the appropriate trigger high voltage to the trigger electrode. An arc-shaped holding member is fixed to the other end, and the holding member is held under pressure against the outer wall of the arc tube so that it can be moved in the axial direction of the arc tube. Therefore, the holding members at one end and the other end of the trigger electrode follow and move in the axial direction of the arc tube, and as a result, no unreasonable force is applied to the trigger electrode, and the trigger In addition to preventing the electrode from lifting off the outer wall of the arc tube, the holding member prevents the trigger electrode from moving in the circumferential direction of the arc tube, resulting in a stable triggering effect. To reliably ignite a lamp without igniting mistakes.

〔Example〕

The present invention will be described in detail below with reference to the drawings.

FIGS. 1 and 2 are explanatory diagrams showing one embodiment of a flash lamp used as an exposure light source for an electrophotographic copying machine.

The flash lamp of this example includes a rod-shaped arc tube 11 made of, for example, quartz glass, and this arc tube 11.
It consists of a pair of electrodes 13 and 14 that form a discharge path 12 along the axial direction inside the arc tube, and a trigger electrode assembly 2 disposed on the outer wall 15 of the arc tube 11.

The trigger electrode assembly 2 is a straight, rigid trigger electrode disposed in contact with or close to the outer wall 15 of the arc tube 11 so as to face the discharge path 12 and extend from one end to the other end along the axial direction of the arc tube 11. 21
and an arc-shaped holding member 22 for holding the trigger electrode 21 fixed to one end side and the other end side of the trigger electrode 21 on the outer wall 15 of the arc tube 11,
23, and a metal fixing member 24 that is connected and fixed to the trigger electrode 21 and fixed at the center of the arc tube 11 in the longitudinal direction.

The trigger electrode 21 is made of stainless steel such as SUS304, and its shape is such that the wire diameter is, for example,
It has a round bar shape of about 0.5 mm and is relatively rigid, and extends linearly in the axial direction of the arc tube 11.

The holding member 22 is in the shape of a metal ring made of stainless steel such as SUS304 and has a wire diameter of about 0.5 mm, and has an arc shape that extends along the circumferential direction of the outer wall 15 of the arc tube 11 over half the circumference thereof. , for example, only one end 25 and the other end 26 of the arc tube 1
The holding member 22 is arranged so as to be in contact with the outer wall 15 of the arc tube 11, and the holding member 22 is elastically held against the outer wall 15 of the arc tube 11, thereby making it difficult for the arc tube 11 to move in the circumferential direction. The arc tube 11 is movable in the axial direction. One end of the trigger electrode 21 is connected to the center of the arc-shaped holding member 22 on the internal curved surface side by, for example, spot welding. The holding member 23 is also fixed to the other end of the trigger electrode 21 in the same way as the holding member 22.

The metal fixing member 24 is connected to the trigger electrode 21
For example, a ring-shaped metal fixing band 27 is connected and fixed to the center of the arc tube 11, and is fixed so as to surround the central outer wall 15 in the longitudinal direction of the arc tube 11 and press the outer wall 15. This fixing band 27
As shown in FIG. 3, a nickel band having a width of, for example, 1 mm and a thickness of 0.3 mm is formed into a ring shape, and a trigger electrode 21 is connected and fixed to the outer surface of the ring by, for example, spot welding. Both ends of the band are overlapped and connected together by spot welding, for example, and then the connecting portion 30
It is formed by bending it towards the ring part so that it does not get in the way.

Reference numerals 28 and 29 indicate a pair of position displacement prevention protrusions that prevent displacement of the side edge position of the fixing band 27;
It is provided on the outer wall 15 of the arc tube 11 so as to sandwich it therebetween. For example, one of these protrusions 28
is the remainder of the exhaust pipe used for exhausting or introducing sealed gas in the manufacture of the arc tube 11, and the other protrusion 29 is formed by welding and fixing, for example, a piece of glass to the outer wall 15 of the arc tube 11. It is. These protrusions 28 and 29 are attached to the fixing band 27.
and is provided so as to protrude from the trigger electrode 21. In this example, these protrusions 28 and 29 not only sandwich the fixing band 27 and prevent the fixing band 27 from displacing the arc tube 11 in the axial direction, but also prevent the fixing band 27 from shifting in the axial direction. This also prevents the trigger electrode 21 from being displaced in the circumferential direction of the arc tube 11.

As shown in FIG. 3, the contact type power supply terminal 3 is made of, for example, a brush, and is fixed to an electrophotographic copying machine (not shown) so as to be in contact with a fixing band 27. A trigger high voltage is supplied to the trigger electrode 21 via the contact type power supply terminal 3 and the fixing band 27.

An example of specific design values for the flash lamp having the above configuration is shown below.

Γ Applied voltage (input voltage) between electrodes 13 and 14: 1000V (DC voltage) Γ Single ignition energy: 90J Γ Peak current between electrodes 13 and 14: 1000A Γ High voltage for trigger: 15kV (frequency: 100kHz) Γ Distance between electrodes 13 and 14: 130 mm Γ Outer diameter of arc tube 11: 11 mm According to the above embodiment, the metal fixing member 24 is made of a metal fixing band 27, and this fixing band 27 is connected to the trigger. The outer wall 1 is connected to and fixed to the electrode 21 and surrounds the outer wall 15 of the arc tube 11 at the center in the longitudinal direction of the arc tube 11.
Since the fixing band 27 is fixed so as to pinch the trigger electrode 21, the position of the fixing band 27 does not shift due to thermal expansion and contraction of the trigger electrode 21, and is always at a fixed central position relative to the arc tube 11. . Therefore, when the contact type power supply terminal 3 is brought into contact with the fixing band 27 and a high voltage for triggering is supplied to the trigger electrode 21, the fixation band 27 and the contact type power supply terminal are connected to each other due to thermal expansion and contraction of the trigger electrode 21. As a result, there is no contact failure with trigger electrode 2.
1 can be reliably supplied with an appropriate trigger high voltage.

In this example, a pair of positional displacement prevention protrusions 28 and 29 are further fixed to the outer wall 15 of the arc tube 11 so as to sandwich the fixing band 27. It is possible to reliably prevent positional displacement of the service band 27 in the axial direction of the arc tube 11.

Then, arc-shaped holding members 22 and 23 are fixed to one end side and the other end side of the trigger electrode 21, and the outer wall 15 of the arc tube 11 is moved so that the holding members 22 and 23 are movable in the axial direction of the arc tube 11. Since the trigger electrode 21 is elastically held under pressure, the holding members 22 and 23 move in the axial direction of the arc tube 11 in response to thermal expansion and contraction of the trigger electrode 21. No unreasonable force acts on the
It is possible to prevent the trigger electrode 21 from floating up from the outer wall 15 of the arc tube 11, and the trigger electrode 21 is fixed to the arc tube 1 by the holding members 22 and 23.
1 is prevented from moving in the circumferential direction, and a pair of protrusions 28 and 29 are formed at the center of the trigger electrode 21.
Since the trigger electrodes 21 are sandwiched between the trigger electrodes 21, the trigger electrodes 21 are prevented from moving in the circumferential direction of the arc tube 11, and as a result, a stable triggering action can be obtained.

In this way, the fixing band 27 and the contact type power supply terminal 3 are protected against thermal expansion and contraction of the trigger electrode 21.
In addition to preventing poor contact with the trigger electrode 21, it is also possible to prevent the trigger electrode 21 from lifting off the outer wall 15 of the arc tube 11 or being displaced in the circumferential direction. can be ignited. Therefore, in the electrophotographic copying machine, exposure can be performed reliably, resulting in high reliability.

Since one of the pair of protrusions 28 and 29 utilizes the remaining part of the exhaust pipe used for exhausting or introducing sealed gas in the manufacture of the arc tube 11, the protrusion 28 is made of a separate piece of glass. Compared to the case of forming using pieces, the number of manufacturing steps is reduced, making manufacturing easier, and material costs can also be saved, making it possible to manufacture at low cost.

〔Example〕

A flash lamp according to the present invention was manufactured based on the specific setting values described above, and an experiment was conducted in which it was actually ignited.
After repeating this process 3.5 million times, we were able to reliably ignite the fire without any ignition errors until the end.

[Effect of idea]

As described above, according to the present invention, a metal fixing member is connected and fixed to the trigger electrode, the fixing member is fixed at the center in the longitudinal direction of the arc tube, and the metal fixing member is fixed at the center in the longitudinal direction of the arc tube. Since the arc-shaped holding member is fixed and held under pressure against the outer wall of the arc tube so as to be movable in the axial direction of the arc tube, the fixing member is protected against thermal expansion and contraction of the trigger electrode. position displacement is prevented,
Therefore, it is possible to reliably supply the high voltage for the trigger to the trigger electrode using the contact type power supply terminal without causing contact failure, and also to prevent the expansion and contraction of the trigger electrode at one end and the other end of the trigger electrode. Following this, the holding member moves in the axial direction of the arc tube, and therefore the unreasonable force acting on the trigger electrode is considerably reduced, making it possible to prevent the trigger electrode from lifting off the outer wall of the arc tube. Moreover, since the trigger electrode is prevented from moving in the circumferential direction of the arc tube by the holding member, a stable triggering action can be obtained, and as a result, the flash lamp can be reliably ignited without causing any ignition errors. .

[Brief explanation of the drawing]

1 and 2 are an explanatory front view and an explanatory vertical side view showing an embodiment of the flash lamp according to the present invention, respectively, and FIG. 3 is a diagram showing the form of the fixing band and the state of contact with the brush. It is a sectional view for explanation. 11... Arc tube, 12... Discharge path, 13, 14
... Electrode, 15 ... Outer wall, 2 ... Trigger electrode assembly, 21 ... Trigger electrode, 22, 23 ... Arc-shaped holding member, 24 ... Fixing member, 27 ... Metal fixing band, 28, 29...Protrusion for preventing positional displacement, 3...Contact type power supply terminal.

Claims (1)

[Claims for Utility Model Registration] A flash lamp comprising an arc tube and a trigger electrode assembly disposed on the outer wall of the arc tube, wherein the trigger electrode assembly is arranged on the outer wall of the arc tube. A linear trigger electrode extending along the axial direction of the arc tube, and a trigger electrode fixed to one end and the other end of the arc tube so as to be movable in the axial direction of the arc tube. The fixing member includes an arc-shaped holding member that is held under pressure against an outer wall, and a metal fixing member that is connected and fixed to the trigger electrode and fixed at a central position in the longitudinal direction of the arc tube. A flash lamp that prevents ignition errors and is characterized in that a high voltage for triggering is supplied by a contact-type power supply terminal placed in contact with the lamp.