JP2005108466A - Discharge lamp lighting device and document exposing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of minutely adjusting light quantity of a discharge lamp, and a document exposing device using this discharge lamp lighting device. <P>SOLUTION: This discharge lamp lighting device comprises a discharge lamp driving circuit for high frequency-driving the discharge lamp 6 including at least a capacitative component, a circuit for obtaining a voltage to be given to the discharge lamp side by switching of a switching element, a dimming light signal generating circuit 20 for generating a dimming signal for dimming the discharge lamp 6, and a frequency variable circuit for varying the driving frequency of the discharge lamp 6 by the discharge lamp driving circuit according to the dimming signal generated from the dimming signal generating circuit 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device for lighting a discharge lamp used in a facsimile machine, a copying machine, and the like, and in particular, a discharge lamp lighting device for dimming control of a discharge lamp containing at least a capacitive component, and The present invention relates to a document exposure apparatus using the same.

  As a discharge lamp lighting device for lighting a rare gas fluorescent lamp used in a conventional facsimile machine or the like, the one described in JP-A-2000-160497 can be exemplified.

JP 2000-160497 (general)

  In the conventional discharge lamp lighting device as described above, a method of varying the voltage applied to the lamp when performing dimming control has been adopted. However, in the method of controlling the lamp voltage, it is difficult to make a fine adjustment because the lamp light quantity changes greatly due to slight fluctuations in the voltage. In other words, when adjusting the lamp in a facsimile machine or the like, unlike the dimming of lighting in a residence or the like, a slight adjustment is required. However, the above-described conventional method has a problem that cannot be achieved.

  The problem to be solved is to provide a discharge lamp lighting device capable of finely adjusting the light quantity of the discharge lamp. Another object of the present invention is to provide an original exposure apparatus using the discharge lamp lighting device.

  A discharge lamp lighting device according to the present invention includes a discharge lamp driving circuit for lighting a discharge lamp including at least a capacitive component by high-frequency driving; a circuit for obtaining a voltage to be supplied to the discharge lamp side by switching of a switching element; A dimming signal generating circuit for generating a dimming signal for dimming the discharge lamp; and driving the discharge lamp by the discharge lamp driving circuit in accordance with the dimming signal generated from the dimming signal generating circuit. And a frequency variable circuit that varies the frequency.

  A discharge lamp lighting device according to the present invention includes a discharge lamp driving circuit for lighting a discharge lamp including at least a capacitive component by high-frequency driving; a circuit for obtaining a voltage to be supplied to the discharge lamp side by switching of a switching element; A dimming signal generating circuit for generating a dimming signal for dimming the discharge lamp; and driving the discharge lamp by the discharge lamp driving circuit in accordance with the dimming signal generated from the dimming signal generating circuit. And a frequency variable circuit that varies the frequency in two stages.

  An original document exposure apparatus according to the present invention includes: the discharge lamp lighting device according to claim 1; and a discharge lamp that is lit by the discharge lamp lighting device to irradiate the original; and the light irradiated to the original And an optical system that leads to the image sensor.

  The discharge lighting device and the document exposure device according to the present invention vary the drive frequency of the discharge lamp by the discharge lamp drive circuit in accordance with the dimming signal generated from the dimming signal generation circuit. Light control is performed, and a minute change in the amount of light is possible. Moreover, since it is the structure which does not apply control to the voltage of a discharge lamp, the apparatus of the same structure can be applied with respect to several models, and there also exists an effect which can reduce cost.

  The fine adjustment necessary for the dimming of the lamp in a facsimile machine or the like was realized by dimming the lighting frequency of the discharge lamp.

A discharge lamp lighting device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In the drawings, the same components are denoted by the same reference numerals and redundant description is omitted. FIG. 1 shows a configuration diagram of a discharge lamp lighting device having a discharge lamp 6 as a load. The discharge lamp 6 is provided with a pair of electrodes for causing discharge in the translucent bulb, and at least one of the electrodes is provided on the outer surface or the inner surface of the translucent bulb. The light-transmitting bulb has a light emitting layer on the inner surface and a rare gas is sealed inside.

  The discharge lamp 6 has an external view in FIG. 5 and a longitudinal cross-sectional view in FIG. 6. As shown in FIG. 6, the discharge vessel 11, the phosphor layer 12, the pair of external electrodes 13 and 13, the aperture 14, and the translucent resin sheet 15. A translucent insulating tube 16 is provided.

  The discharge vessel 11 is made of a glass bulb 11a having a diameter of 10 mm and an effective length of 370 mm that is elongate and hermetically sealed at both ends. . The phosphor layer 12 is formed on the inner surface of the discharge vessel 11 except for a slit-like portion along the longitudinal direction.

  The pair of external electrodes 13 and 13 are each made of an aluminum foil, and are disposed by being attached to the outer surface of the discharge vessel 11 so as to face each other in parallel and apart from each other as shown in FIG. The external electrode 13 is attached in advance to one surface of a translucent resin sheet 15 described later, and is disposed at a predetermined position on the outer surface of the discharge vessel 11 by winding the translucent resin sheet 15 around the outer periphery of the discharge vessel 11. Is done.

  The external electrode 13 includes a wavy electrode main portion 13a, a terminal connection portion 13b, and a terminal 13c. The electrode main portion 13 a is configured to have a wave shape and extend over most of the longitudinal direction of the discharge vessel 11. The terminal connection portion 13b is disposed so as to be connected to one end of the electrode main portion 13a, and is formed in a rectangular shape so that a contact area with the terminal 13c is increased. The terminal 13c is bonded to the terminal connection portion 13b with a conductive adhesive, and protrudes from the translucent resin sheet 15 and the translucent insulating tube 16 which is a translucent heat shrinkable tube to the outside.

  The aperture 14 is formed by a portion where the phosphor layer 12 is not formed in a slit shape along the longitudinal direction of the discharge vessel 11. Therefore, the portion of the aperture 13 of the discharge vessel 11 is seen through the inside of the discharge vessel 11 through the glass bulb 11a.

  The translucent resin sheet 15 is made of transparent PET, has a length that covers the substantially entire length of the discharge vessel 11, and has a width that covers the aperture 14 with respect to the peripheral direction of the discharge vessel 11. Yes. As described above, the pair of external electrodes 13 and 13 are attached to one surface at a predetermined interval. Further, an acrylic pressure-sensitive adhesive is applied thereon and adhered to the outer surface of the discharge vessel 11. Thus, the pair of external electrodes 13 and 13 are disposed on both sides of the aperture 14, but the translucent resin sheet 15 is also stuck on the aperture 14.

  The translucent insulating tube 16 is made of a transparent fluororesin and covers the entire circumference of the discharge vessel 11 from above the external electrodes 13 and 13 and the aperture 14.

As shown in FIG. 7, the equivalent circuit of the discharge lamp 6 comprises a series circuit of a capacitor C _IN1 , a load resistor R _L and a capacitor C _IN2 , and a parallel circuit of a capacitor C _OUT1 and a capacitor C _OUT2 . Capacitor C _IN1 and capacitor C _IN2 are capacitances formed between external electrode 13 and the inner surface of discharge vessel 11. Therefore, the capacitances of the capacitors C _IN1 and C _IN2 are the area of the external electrode 13, the relative permittivity and thickness of the glass that is the constituent material of the discharge vessel 11, and the external electrode 13 attached to the outer surface of the discharge vessel 11. It is determined by the relative dielectric constant and thickness of the adhesive that is being worn. Thus, the discharge lamp 6 includes at least a capacitive component.

The power supply to the discharge lamp 6 is performed through the following route. The input power supply voltage supplied between the first terminal and the third terminal in the input section CN1 is stored in the capacitor C1, and is switched by the FET1 which is a switching element of the boosting chopper circuit through the choke coil L1 and boosted. To do. That is, 1/2 (LI ² ) energy is accumulated in the choke coil L1 when the FET 1 is in the on state, and the induced voltage generated in the choke coil L1 is transferred via the diode D1 when the FET 1 shifts from the on state to the off state. Accumulated in the capacitor C2. A series circuit including a coil L0 and a capacitor C0 is connected between the drain and source of the FET1, and when the potential of the capacitor C0 exceeds the capacitor C2, a current is passed to charge the capacitor C2.

  The voltage stored in the capacitor C2 is boosted by the step-up transformer T1, reaches the secondary winding P4, and is applied to the discharge lamp 6.

  On the other hand, as a discharge lamp driving circuit for driving the discharge lamp 6 by high-frequency driving, FET2 and FET3 which are switching elements, two buffers each constituted by a transistor Q1 and a transistor Q2, and a two-stone driving circuit (push-pull circuit) ) A circuit composed of 4 etc. is used. Both the two-stone driving circuit 4 and the boosting driving circuit 5 described later operate by being supplied with electric power from a power supply unit including a transistor Q3 and a capacitor C10.

  In the present embodiment, control is performed so that the voltage boosted by the boosting chopper circuit becomes predetermined. Therefore, in order to detect the potential accumulated in the smoothing capacitor C2, a series circuit including resistors R1 and R2 is connected in parallel to the capacitor C2, and the voltage at the connection point between the resistors R1 and R2 is rectified via the diode D2. A configuration is adopted in which the voltage is integrated by the resistor R3 and the capacitor C3 and led to the booster drive circuit 5.

  The step-up drive circuit 5 switches the FET 1 with the drive signal OUT1 so that the integrated voltage is constant. In this way, constant voltage control is performed so that the voltage boosted by the boost chopper circuit becomes predetermined.

  The two-stone drive circuit 4 gives the control signal OUT2 to the buffer constituted by the transistor Q1 and the like via one output terminal, and gives the control signal OUT3 to the buffer constituted by the transistor Q2 and the like via the other output terminal. By driving the FETs 2 and 3 connected to the respective buffers, a high frequency having a required frequency is given from the primary windings P1 and P2 of the step-up transformer T1 to the discharge lamp 6 via the secondary winding P4. The discharge lamp 6 is configured to be lit by being driven at a high frequency.

  In this embodiment, a dimming signal generation circuit 20 for generating a dimming signal for dimming the discharge lamp is provided, and the dimming signal generation circuit 20 responds to an operation of the volume VR by the operator. A dimming signal having a direct current level is generated. The dimming signal is given to the fourth terminal of the input section CN1.

  The two-stone drive circuit 4 outputs a control signal OUT2 and a control signal OUT3 according to the value of the capacitor C4 connected to the CT terminal and the value of the resistor (here, a series circuit of VR1 and R4) connected to the RT terminal. Change the frequency. In other words, the two-stone drive circuit 4 charges the capacitor C4 and discharges the electric charge of the capacitor C4 by the series circuit of the resistor VR1 and the resistor R4. As a result, the voltage appearing at the capacitor C4 is at the right corner of FIG. The waveform of the triangular wave is as shown, and the control signal OUT2 and the control signal OUT3 are generated and output at a frequency corresponding to the frequency of the triangular wave.

  In this embodiment, the frequency change between the control signal OUT2 and the control signal OUT3 described above performed by the two-stone drive circuit 4 is used. That is, the dimming signal generated by the dimming signal generation circuit 20 is applied to the connection point of the resistors VR1 and R4 via the diode D3, the discharge time is changed, the frequency of the triangular wave is changed, and the control signal OUT2 and the control signal are controlled. The frequency with the signal OUT3 is changed. As described above, the capacitor C4 and the series circuit of the resistors VR1 and R4 can change the drive frequency of the discharge lamp 6 by the discharge lamp drive circuit in accordance with the dimming signal generated from the dimming signal generation circuit 20. A frequency variable circuit is configured.

  2 to 4 show the lamp voltage and the lamp in the discharge lamp 6 when the DC level of the dimming signal is 4.027V, 3.885V, and 3.819V, respectively, in the apparatus of the first embodiment. The lighting frequency by current is shown. The lighting frequency was changed to 42.41 KHz, 50.15 KHz, and 57.30 KHz corresponding to the light control signal levels 4.027 V, 3.885 V, and 3.819 V. In each case, the lamp light amounts were YG70000Lx, YG80000Lx, and YG90000Lx, and a minute change in the light amount could be realized.

  FIG. 8 shows the configuration of a second embodiment of the discharge lamp lighting device according to the present invention. In this embodiment, the following configuration is adopted as the frequency variable circuit. A potential between the resistors R5 and R6 connected in series is applied to a connection point between the resistors VR1 and R4 through the diode D3. The collector of the transistor Q4 is connected to the connection point of the resistor R5 and the resistor R6, the emitter of the transistor Q4 is connected to the ground side of the resistor R6, and a dimming signal is applied to the base of the transistor Q4 to turn on / off the transistor Q4. (Switching) switches the potential between the resistor R5 and the resistor R6 to a low level or a high level. As a result, the frequency of the triangular wave, which is the voltage across the capacitor C4, is changed in two stages by changing the discharge time through the path between the resistor VR1 and the resistor R4, and the frequencies of the control signal OUT2 and the control signal OUT3 are changed in two stages. To do. Other than this, the same configuration as that of the first embodiment shown in FIG. 1 is adopted.

  9 and FIG. 10, in the device of the second embodiment, the potential between the resistor R5 and the resistor R6 connected in series by turning on and off the transistor Q4 by the dimming signal is 3.321 V (Q4 The lighting frequency by the lamp voltage and the lamp current in the discharge lamp 6 in the case of being off) and 669.7 mV (Q4 on) is shown. Corresponding to 3.321 V and 669.7 mV, the lighting frequency was changed to 47.58 KHz and 57.64 KHz. In each case, the lamp light amounts were YG65000Lx and YG85000Lx, and a minute change in the light amount could be realized in two stages.

  In the above description, a configuration in which the voltage applied to the discharge lamp is fed back and controlled at a constant voltage is adopted. However, a configuration in which a lighting frequency control is performed by feeding back a signal on the discharge lamp side may be used. You may employ | adopt the structure to perform.

  For example, as shown in FIG. 11, a facsimile machine or the like using the conventional discharge lamp lighting device as described above irradiates a document 50 with a discharge lamp 51, and uses an optical system (not shown) to reflect the reflected light. The image sensor 53 is condensed, and an original image is photoelectrically converted to obtain an image signal, which is sent to the image processing unit 54. As described above, the document exposure apparatus includes the discharge lamp lighting device, the discharge lamp that is turned on by the discharge lamp lighting device, and irradiates the document, and the optical system that guides the light irradiated on the document 50 to the image sensor. To do. The image information processed by the image processing unit 54 is sent to an output unit 56 such as a transmission unit for processing if it is a facsimile machine.

  For example, a read synchronization signal corresponding to the reading time of one line is given from the image processing unit 54 to the image sensor 53, and the image sensor 53 performs image processing on the image signal for each line in synchronization with the read synchronization signal. Send to section 54. The reading synchronization signal is also given to the discharge lamp lighting device 52 that lights the discharge lamp, and the discharge lamp lighting device 52 is used to turn on / off the drive signal of the discharge lamp 51. A signal for controlling on / off of the apparatus is supplied to the discharge lamp lighting device 52 and the image processing unit 54 from the operation unit 55 operated by the operator.

The circuit diagram which shows the structure of the 1st Example in the discharge lamp lighting device which concerns on this invention. It is a wave form diagram which shows the change of the lighting frequency implement | achieved by the 1st Example in the discharge lamp lighting device which concerns on this invention, Comprising: The wave form diagram corresponded when the dimming signal is 4.027V. It is a wave form diagram which shows the change of the lighting frequency implement | achieved by the 1st Example in the discharge lamp lighting device which concerns on this invention, Comprising: The wave form diagram equivalent to the case where a dimming signal is 3.885V. It is a wave form diagram which shows the change of the lighting frequency implement | achieved by the 1st Example in the discharge lamp lighting device which concerns on this invention, Comprising: The wave form diagram corresponded when a dimming signal is 3.819V. The figure which shows the external appearance of the discharge lamp used for the discharge lamp lighting device which concerns on this invention. The longitudinal cross-sectional view of the discharge lamp shown in FIG. The figure which shows the equivalent circuit of the discharge lamp shown in FIG. The circuit diagram which shows the structure of the 2nd Example in the discharge lamp lighting device which concerns on this invention. It is a wave form diagram which shows the change of the lighting frequency implement | achieved by the 2nd Example in the discharge lamp lighting device which concerns on this invention, Comprising: The wave form diagram in case a transistor is OFF. It is a wave form diagram which shows the change of the lighting frequency implement | achieved by the 2nd Example in the discharge lamp lighting device which concerns on this invention, Comprising: The wave form diagram in case a transistor is ON. 1 is a schematic block diagram of a facsimile machine or the like configured using a discharge lamp lighting device according to the present invention.

Explanation of symbols

1 FET (switching element of boost chopper circuit)
2 FET (Inverter circuit switching element)
3 FET (switching element of inverter circuit)
4 2-stone drive circuit
5 Booster drive circuit
6 Discharge lamp 11 Discharge vessel
12 Phosphor layer
13 External electrode
14 Aperture
15 Translucent resin sheet
16 Translucent insulating tube 20 Dimming signal generation circuit T1 Step-up transformer

Claims (3)

A discharge lamp driving circuit for driving a discharge lamp including at least a capacitive component by high-frequency driving;
A circuit for obtaining a voltage to be applied to the discharge lamp side by switching of the switching element;
A dimming signal generating circuit for generating a dimming signal for dimming the discharge lamp;
A frequency variable circuit that varies a driving frequency of the discharge lamp by the discharge lamp driving circuit in accordance with a dimming signal generated from the dimming signal generation circuit;
A discharge lamp lighting device comprising: A discharge lamp driving circuit for driving a discharge lamp including at least a capacitive component by high-frequency driving;
A circuit for obtaining a voltage to be applied to the discharge lamp side by switching of the switching element;
A dimming signal generating circuit for generating a dimming signal for dimming the discharge lamp;
A frequency variable circuit that varies the driving frequency of the discharge lamp by the discharge lamp driving circuit in two stages in accordance with the dimming signal generated from the dimming signal generation circuit;
A discharge lamp lighting device comprising: A discharge lamp lighting device according to claim 1 or 2;
A discharge lamp that is lit by the discharge lamp lighting device and irradiates the original;
An optical system for guiding the light emitted to the document to an image sensor;
An original exposure apparatus comprising:

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