JPH08102371A - Lamp lighting device, electric device, lighting system and copying device - Google Patents

Abstract

PURPOSE: To prevent a rush current without deteriorating the buildup characteristic of a lamp. CONSTITUTION: A current detecting circuit 22 detects a lamp current flowing through a variable resistance R1, and a control circuit 23 controls a field-effect transistor Q1 according to the voltage values of the current detection circuit 22 and of the variable resistance R1. If a rush current is generated in the variable resistance R1, the voltage of a step-down chopper circuit 21 is lowered by the control circuit 23. Under normal conditions, a lamp current is monitored, and the field-effect transistor Q1 is controlled by the control circuit 23 with the lamp current held constant to hold the light output of a halogen lamp IL constant. When the resistance value of the variable resistance R1 is smaller than 5% of the resistance value of the halogen lamp IL, the rush current cannot be decreased sufficiently; when the resistance value of the variable resistance R1 is greater than 15%, the buildup characteristic and thus circuit efficiency decrease; therefore, the resistance value must be in the range 5 to 15%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp lighting device for lighting a lamp by semiconductor switching means, an electric device, a lighting device and a copying machine.

[0002]

2. Description of the Related Art Heretofore, as a lamp lighting device of this type, a structure disclosed in Japanese Patent Application Laid-Open No. 1-251585 has been known.

The structure described in Japanese Patent Laid-Open No. 1-251585 is for rectifying and smoothing a commercial AC power source, and lowering the voltage by a step-down chopper circuit for switching a transistor to light a halogen lamp.

[0004]

However, when the halogen lamp is started at the time of cold resistance at room temperature, that is, at the so-called cold start, the resistance is as low as about 1/10 of the normal value, and an inrush current of about 10 times the rated current occurs. Therefore, the breakdown voltage of the transistor of the step-down chopper circuit must be increased to about 3 to 4 times the rated current, which increases the cost and lowers the reliability.

The present invention has been made in view of the above problems, and an object thereof is to provide a lamp lighting device, an electric device, a lighting device, and a copying device which prevent an inrush current without deteriorating the rising characteristics of the lamp. To do.

[0006]

According to a first aspect of the present invention, there is provided a lamp lighting device, wherein semiconductor switching means for switching the output of a power supply by a semiconductor switching element and supplying the same to the lamp, and between the semiconductor switching means and the lamp. 5% to 15% of the cold resistance value of the lamp inserted
%, And a resistance component having a resistance value of%.

A lamp lighting device according to a second aspect of the present invention is the lamp lighting device according to the first aspect, wherein the semiconductor switching means is a step-down chopper circuit.

A lamp lighting device according to a third aspect of the present invention is a semiconductor switching means for switching the output of a power source by a semiconductor switching element and supplying the same to a lamp, and a resistance component interposed between the semiconductor switching means and the lamp. And the resistance value of this resistance component is 5 of the cold resistance value.
% To 15%, and a resistance value adjusting means for varying the value.

A lamp lighting device according to a fourth aspect is the lamp lighting device according to any one of the first to third aspects, in which current detecting means for detecting a current value flowing in the resistance component and current detected by the current detecting means. And a control means for varying the output of the semiconductor switching means according to the value.

An electric device according to a fifth aspect comprises the lamp lighting device according to any one of the first to fourth aspects, and a housing for accommodating the lamp lighting device.

A lighting device according to a sixth aspect comprises the lamp lighting device according to any one of the first to fourth aspects, and a lighting device main body which houses the lamp lighting device.

According to a seventh aspect of the present invention, there is provided a copying apparatus including the lamp lighting device according to any one of the first to fourth aspects and a copying device main body which houses the lamp lighting device.

[0013]

In the lamp lighting device according to the first aspect of the present invention, since the resistance value of the resistance component interposed between the semiconductor switching means and the lamp is set to 5% to 15% of the cold resistance value of the lamp, the rising characteristic is deteriorated. In addition, inrush current can be prevented.

A lamp lighting device according to a second aspect of the present invention is the lamp lighting device according to the first aspect, in which the semiconductor switching means is a step-down chopper circuit, so that the reliability of the step-down operation is not deteriorated.

In the lamp lighting device according to the third aspect, the resistance value of the resistance component is 5% to 15% of the cold resistance value by the resistance value adjusting means.
Therefore, even if the cold resistance value of the lamp varies, the inrush current can be prevented without deteriorating the rising characteristic corresponding to the lamp.

The lamp lighting device according to a fourth aspect is the lamp lighting device according to any one of the first to third aspects, in which the current value flowing through the resistance component is detected by the current detecting means, and the current detected by the current detecting means is detected. Since the output of the semiconductor switching means is varied by the control means according to the value, the output of the semiconductor switching means can be varied even if an inrush current occurs, and the lamp current can be kept constant.

Since the electric device according to claim 5 comprises the lamp lighting device according to any one of claims 1 to 4 and a housing for accommodating the lamp lighting device, the inrush current can be maintained without deteriorating the rising characteristic. Can also be prevented.

Since the lighting device according to claim 6 comprises the lamp lighting device according to any one of claims 1 to 4 and the lighting device main body for housing the lamp lighting device, the rushing-in without deteriorating the rising characteristic. Electric current can also be prevented.

Since the copying apparatus according to claim 7 comprises the lamp lighting device according to any one of claims 1 to 4 and the copying device main body which houses this lamp lighting device, the rushing-in is performed without deteriorating the rising characteristic. Electric current can also be prevented.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the copying apparatus of the present invention will be described below with reference to the drawings.

In FIG. 2, reference numeral 11 denotes a copying apparatus main body. The copying apparatus main body 11 has a glass surface for placing an original document (not shown) on an upper portion thereof, and an openable / closable lid 12 is mounted on the glass surface. There is. Further, inside the copying apparatus main body 11, there are arranged a conveying means 13 for conveying the paper P, a developing means 14 for developing and fixing an image on the conveyed paper, and the like.

Further, the rail 15 is parallel to the glass surface.
A lamp unit 16 for a scanner serving as a lighting device is movably provided on the rail 15, and a halogen lamp IL, which is a light bulb as a load, is housed in the case body of the lamp unit 16. . A lamp lighting circuit 17 as a lamp lighting device is electrically connected to the halogen lamp IL. The halogen lamp IL has a cold resistance value of 1.2Ω to 1.
Use 5Ω and a rated output of 100W to 400W.

In the lamp lighting circuit 17, as shown in FIG. 1, for example, a step-down chopper circuit 21 as semiconductor switching means is connected to a DC power source E obtained by rectifying and smoothing a commercial AC power source. Is a MOS as a semiconductor switching element between both ends of the DC power source E.
A series circuit of a field effect transistor Q1 and a diode D1 is formed, and a series circuit of an inductor L1 and a capacitor C1 is connected in parallel to the diode D1.

Further, the capacitor C1 is connected in series with a variable resistor R1 and a halogen lamp IL as a resistance component capable of varying in the vicinity of 0.1Ω for preventing an inrush current.

A current detection circuit 22 as current detection means is connected to one end of the variable resistor R1.
The other end of the variable resistor R1 is connected to a control circuit 23 as a control means together with 22, and the control circuit 23 is connected to the gate of the field effect transistor Q1.

Further, a resistance value adjusting circuit 24 as resistance value adjusting means is connected to the variable resistance R1, and the resistance value adjusting circuit 24 changes the variable resistance according to the cold resistance value of the halogen lamp IL.
Set the resistance of R1 to 5% to 15% of the cold resistance of the halogen lamp IL.
Adjust to about%.

Next, the operation of the above embodiment will be described.

First, an original is placed on a glass surface (not shown), the lamp unit 16 is moved along the rail 15 with the halogen lamp IL turned on, the image of the original is read, and the paper P is conveyed by the conveying means 13. Is conveyed, and the developing means 14 develops and fixes the paper P.

Then, according to the cold resistance value of the halogen lamp IL, the resistance value adjusting circuit 24 adjusts the resistance value of the variable resistor R1 to 5% to 15% of the cold resistance value of the halogen lamp IL.

When the halogen lamp IL is turned on, the field effect transistor Q1 is switched by the control circuit 23 to reduce the voltage and improve the power factor. That is, the inductor L1 is charged while the field effect transistor Q1 is turned on by the control circuit 23, the inductor L1 is discharged by turning off the field effect transistor Q1, and the capacitor C1 is charged via the diode D1. Turn on the halogen lamp IL.

The current detection circuit 22 detects the lamp current flowing through the variable resistor R1, and the control circuit 23 detects the lamp current based on the voltage values of the current detection circuit 22 and the variable resistor R1.
The control circuit 23 controls the field effect transistor Q1.
That is, for example, when an inrush current occurs in the variable resistor R1, the control circuit 23 lowers the voltage of the step-down chopper circuit 21, and the lamp current is normally monitored so that the control circuit 23 keeps the lamp current constant. The field effect transistor Q1 is controlled by to make the light output of the halogen lamp IL constant. When detecting the lamp current, the resistance value of the variable resistance R1 which has been changed in advance is detected.

According to the above embodiment, the cold resistance value of the halogen lamp IL is 1.2Ω to 1.5Ω, whereas the resistance of the variable resistor R1 is 0.1Ω, so that the halogen lamp IL is cold-started. In this case, inrush current can be prevented and the rising characteristics and efficiency are not deteriorated. The resistance value of the variable resistor R1 is not limited to 0.1Ω, and may be 5% to 15% of the cold resistance value of the halogen lamp IL. That is, when the resistance value of the variable resistor R1 is smaller than 5% of the resistance value of the halogen lamp IL, the inrush current cannot be sufficiently reduced, and conversely, when the resistance value is larger than 15%. Since the rise characteristics deteriorate and the circuit efficiency decreases, the range is set to 5% to 15%.

Further, since the resistance value is changed by the variable resistance R1, the resistance value can be changed corresponding to the cold resistance value of the halogen lamp IL to be mounted. It is possible to deal with variations such as when the factor is.

Further, not only the prevention of inrush current but also the variable resistor R1 can be used as a monitor for current detection, voltage detection and power detection, so that the number of parts is not increased significantly.

Further, the field effect transistor Q1 is a MOS
By adopting a mold, stable operation can be performed against pulse noise.

Further, the electric device is not limited to a copying device having a scanner or the like, but any device using a lamp such as a light bulb can obtain the same effect, and the electric device can be a copying device or the like. The device is included, and the main body of the lighting device and the housing are not limited to the case body of the lamp unit 16 and the like, and the same effects can be obtained by a general lighting device.

Further, even if the resistance component is a fixed resistance of about 0.1Ω, the same effect can be obtained with a simple structure.

[0038]

According to the lamp lighting device of the present invention, the resistance value of the resistance component interposed between the semiconductor switching means and the lamp is 5% to 15% of the cold resistance value of the lamp.
Therefore, the inrush current can be prevented without deteriorating the rising characteristic.

According to the lamp lighting device of the second aspect,
In addition to the lamp lighting device according to the first aspect, since the semiconductor switching means is a step-down chopper circuit, it is possible to prevent the reliability of the step-down operation from being lowered.

According to the lamp lighting device of the third aspect,
The resistance value of the resistance component is set to 5% of the cold resistance value by the resistance value adjusting means.
Since it is changed to 15%, even if the cold resistance value of the lamp varies, the inrush current can be prevented without deteriorating the rising characteristic corresponding to the lamp.

According to the lamp lighting device of the fourth aspect,
In addition to the lamp lighting device according to any one of claims 1 to 3, a current value flowing in a resistance component is detected by a current detection means,
Since the output of the semiconductor switching means is varied by the control means according to the current value detected by the current detecting means, the output of the semiconductor switching means can be varied even if an inrush current occurs, and the lamp current can be kept constant.

According to the electric device of the fifth aspect, since the lamp lighting device according to any one of the first to fourth aspects and the housing for housing the lamp lighting device are provided, the rising characteristics are not deteriorated. Inrush current can also be prevented.

According to the lighting device of the sixth aspect, the lamp lighting device according to any one of the first to fourth aspects is provided, and the lighting device main body for housing the lamp lighting device is provided.
Inrush current can also be prevented without deteriorating the rising characteristics.

According to the copying apparatus of claim 7, the lamp lighting device according to any one of claims 1 to 4 is provided, and the copying apparatus main body for accommodating the lamp lighting device is provided.
Inrush current can also be prevented without deteriorating the rising characteristics.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a lamp lighting device of the present invention.

FIG. 2 is an explanatory diagram showing the above copying apparatus.

[Explanation of symbols]

11 Copying device main body 16 Lamp unit as lighting device 17 Lamp lighting circuit as lamp lighting device 21 Step-down chopper circuit as semiconductor switching means 22 Current detection circuit as current detection means 23 Control circuit as control means 24 Resistance value adjustment means Value adjustment circuit E DC power supply IL Halogen lamp Q1 Field effect transistor R1 as semiconductor switching element Variable resistance as resistance component

Claims (7)

[Claims] 1. A semiconductor switching means for switching an output of a power supply by a semiconductor switching element to output the same and supplying it to a lamp, and 5% to 15% of a cold resistance value of the lamp interposed between the semiconductor switching means and the lamp. %, And a resistance component having a resistance value of%. 2. The lamp lighting device according to claim 1, wherein the semiconductor switching means is a step-down chopper circuit. 3. A semiconductor switching means for switching an output of a power supply by a semiconductor switching element to output the same and supplying it to a lamp, a resistance component interposed between the semiconductor switching means and the lamp, and a resistance value of the resistance component. And a resistance value adjusting means for varying the cold resistance value to 5% to 15% of the cold resistance value. 4. A current detecting means for detecting a value of a current flowing through a resistance component, and a control means for varying an output of the semiconductor switching means according to a current value detected by the current detecting means. The lamp lighting device according to any one of claims 1 to 3. 5. An electric device comprising: the lamp lighting device according to claim 1; and a housing that houses the lamp lighting device. 6. A lighting device comprising: the lamp lighting device according to claim 1; and a lighting device body that houses the lamp lighting device. 7. A copying apparatus comprising: the lamp lighting device according to claim 1; and a copying apparatus main body accommodating the lamp lighting device.