JPH07220890A - Fluorescent lamp lighting device and image forming device - Google Patents

Abstract

PURPOSE:To easily set a fluorescent lamp to the lighted state. CONSTITUTION:The detection signal from a dimming sensor 2 detecting the luminescence quantity of a fluorescence lamp FL is inputted to a control microcomputer section 3, it is A/D-converted to form the fluorescent lamp lighting signal PWM controlling the lighting of the fluorescent lamp FL, the fluorescent lamp lighting signal PWM is inputted to a fluorescent lamp lighting circuit 4, and a transistor Q is turned off to control the lighting of the fluorescent lamp FL. The control microcomputer section 3 outputs the fluorescent lamp lighting signal PWM having a constant ratio between the on-period and the off-period of the applied power regardless of the detection signal value from the dimming sensor 2 in the prescribed period at the time of the lighting start of the fluorescent lamp FL to the fluorescent lamp lighting circuit 4, and it outputs the fluorescent lamp lighting signal PWM having the ratio between the on-period and the off-period of the applied power determined based on the detection signal value from the dimming sensor 2, to the fluorescent lamp lighting circuit 4 after the prescribed period at the time of the lighting start is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a printer,
A fluorescent lamp lighting device suitable for lighting and controlling a fluorescent lamp for irradiating an image forming object provided in various other electronic devices, and a copying machine for irradiating the image forming object with the fluorescent lamp and forming and outputting an image on a recording medium, The present invention relates to an image forming apparatus such as a printer.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a copying machine or a printer, a structure in which an image forming object is irradiated with a fluorescent lamp and an image is output on a recording medium by an electrophotographic method or the like is widely adopted.

A lighting circuit of a fluorescent lamp drives an inverter transformer by an oscillator provided on the primary side, and a high frequency voltage output from the secondary side is passed through a fluorescent lamp lighting current limiting inductance to a filament at both ends of the fluorescent lamp. It is connected. A shunt switch such as a transistor is connected to both ends of the fluorescent lamp, and the shunt switch is turned on / off by a fluorescent lamp lighting signal.

[0004]

However, the lighting circuit of the fluorescent lamp has a dimming operation (100% du) immediately after the start of lighting.
ty), the fluorescent lamp is turned on immediately after it is new. However, when the fluorescent lamp deteriorates with time, it is difficult to shift to lighting and there are many cases where the fluorescent lamp fails to turn on.

FIG. 6 is a timing chart showing an example of the output of a dimming sensor installed near a fluorescent lamp. When the fluorescent lamp is old, the lighting signal input is the same as when the fluorescent lamp is new. It shows that it is possible.

The present invention solves the above-mentioned conventional problems,
An object of the present invention is to provide a fluorescent lamp lighting device and an image forming apparatus capable of easily shifting the fluorescent lamp to a lighting state.

[0007]

Therefore, a fluorescent lamp lighting device according to the present invention is provided with a fluorescent lamp lighting means for turning on / off the power supply to the fluorescent lamp, and a light amount detection for detecting the light emission amount of the fluorescent lamp. Means, and the detection value of the light amount detecting means is input to determine a ratio of on time and off time of power application to the fluorescent lamp, and an on / off signal of power application is output to the fluorescent lamp lighting means to output the fluorescent lamp. Is a fluorescent lamp lighting device provided with a control means for performing a control so as to be a predetermined constant light quantity value, wherein the control means is within a predetermined time when the fluorescent lamp is turned on, regardless of the detection value of the light quantity detection means. Without outputting the ON / OFF signal to the fluorescent lamp lighting means with a constant ratio of ON time and OFF time of power supply application, after the predetermined time at the time of lighting start is over, the fluorescent lamp is based on the detection value of the light amount detecting means. ON and OFF time of power supply to the The on-off signals to determine the ratio between the structure and outputs to the fluorescent lamp lighting device, it is intended to achieve the above object.

Further, the present invention aims to achieve the above object of the image forming apparatus by providing the fluorescent lamp lighting device having the above-mentioned configuration.

[0009]

With the above configuration of the fluorescent lamp lighting device, an ON / OFF signal that keeps the ratio of the ON time and the OFF time of the power supply constant during the predetermined time when the fluorescent lamp is turned on is started regardless of the detection value of the light amount detecting means. By operating the fluorescent lamp lighting means, the fluorescent lamp can be easily switched to the lighting state.

After the end of the predetermined time at the time of lighting activation, the fluorescent lamp lighting means is turned on and off by an on / off signal that determines the ratio of the on time and the off time of power application to the fluorescent lamp based on the detection value of the light quantity detecting means. By the operation, the fluorescent lamp can be maintained in a stable lighting state with a predetermined light amount.

Further, since the fluorescent lamp lighting device is provided, the image forming apparatus can use the fluorescent lamp stably and effectively for a long period of time, and can efficiently form an image.

[0012]

FIG. 1 is a block diagram of a fluorescent lamp lighting device according to an embodiment of the present invention for lighting and controlling a fluorescent lamp provided in an image forming apparatus.

T is an inverter transformer, which drives the inverter transformer T by turning on / off the switching element 1 by an oscillator provided on the primary side, and the high frequency voltage output from the secondary side has a fluorescent lamp lighting current limiting inductance L. It is connected to the filaments at both ends of the fluorescent lamp FL via. The diode bridge DB and the transistor Q connected to both ends of the fluorescent lamp constitute a shunt switch.

A dimming sensor 2 for detecting the amount of light emission is installed near the fluorescent lamp FL, and a detection signal from the dimming sensor 2 is input to the control microcomputer unit 3 to
A fluorescent lamp lighting signal for controlling the lighting of the fluorescent lamp is formed by D / D conversion. The fluorescent lamp lighting signal becomes a PWM signal and is input to the fluorescent lamp lighting circuit 4. The fluorescent lamp lighting circuit 4 is configured to turn on / off the transistor Q based on the PWM signal which is a fluorescent lamp lighting signal.

When the transistor Q is on, the output of the inverter transformer T is not applied to the fluorescent lamp FL,
When the transistor Q is off, the inverter transformer T
Is applied to the fluorescent lamp FL, so that the detection value of the dimming sensor 2 becomes constant by changing the pulse width of the PWM signal which is the fluorescent lamp lighting signal from the control microcomputer unit 3. This is a configuration capable of controlling the lighting state of the lamp FL.

The control of the lighting state of the fluorescent lamp FL in this embodiment will be described below.

FIG. 2 is a timing chart showing an example of the fluorescent lamp lighting signal and the output of the dimming sensor 2 installed near the fluorescent lamp. Even if the fluorescent lamp is a little old, the waveform of the fluorescent lamp lighting signal is shown. It is shown that it is possible to light.

That is, in this embodiment, as shown in FIG. 2, the predetermined time, the on-time, and the off-time are fixed to a certain ratio immediately after the start of the lighting signal of the fluorescent lamp, and then the dimming operation is started. I'm taking a sequence like this. Specifically 1
Send a 50% duty pulse for 00 ms and then 1
Light control is started from 00% duty.

With the above structure, if the lighting is switched on within 100 mS, the normal dimming operation can be started. Therefore, the lighting can be easily switched on even when the fluorescent lamp is initially deteriorated.

[Other Embodiments] [Embodiment 2] Embodiment 2 has the same block configuration as that of the above embodiment, and is characterized in lighting signal control.

That is, as shown in the flow chart of FIG. 3, the lighting is switched on within 100 mS (steps S1, S
2) If the amount of light from the fluorescent lamp is above a certain amount, the dimming operation starts normally (S3), but if the amount of light is not above a certain amount, it is judged that it is time to replace the fluorescent lamp. The lighting operation is stopped (S4), and a message prompting the replacement of the fluorescent lamp is displayed (S5).

By adopting the above configuration, it is possible to clarify the replacement time of the fluorescent lamp.

[Third Embodiment] In the third embodiment, in the same block configuration as the above-mentioned embodiment, as shown in the flowchart of FIG. 4, when the lighting does not shift to 100 mS (S
21 and S22), the period of 50% duty is further extended (S23) so that the lighting state can be entered even when the deterioration of the fluorescent lamp further progresses.

[Embodiment 4] In Embodiment 4, in the same block configuration as the above-mentioned embodiment, as shown in the flowchart of FIG. 5, when the lighting does not shift to 100 mS (S3
1, S32), and further extend the period of 50% duty (S
33), if it still does not reach the predetermined light intensity (S3
5) It is determined that it is time to replace the fluorescent lamp, the lighting operation is stopped, and a message prompting replacement of the fluorescent lamp is displayed (S36).

With the above construction, it becomes possible to use the fluorescent lamp as much as possible until it reaches the end of its useful life.

[Example of Image Forming Apparatus] In an example of the image forming apparatus according to the present invention, the fluorescent lamp for illuminating the image forming object is controlled to be turned on by the fluorescent lamp lighting device of the above example, and the image forming object is formed. An image forming apparatus such as a copying machine or a printer that irradiates an object and forms and outputs an image on a recording medium, and the fluorescent lamp lighting device can easily shift the fluorescent lamp to a lighting state by the action and effect of the fluorescent lamp lighting device. The apparatus can use a fluorescent lamp stably and effectively for a long period of time to efficiently form an image.

[0027]

As described above, according to the present invention,
The fluorescent lamp can be easily switched to the lighting state. It is also possible to know when to replace the fluorescent lamp.

Further, the image forming apparatus of the present invention can stably and effectively use the fluorescent lamp for a long period of time to efficiently form an image.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment.

FIG. 2 is a lighting control timing chart of an example.

FIG. 3 is a lighting control flowchart of the second embodiment.

FIG. 4 is a lighting control flowchart of a third embodiment.

FIG. 5 is a lighting control flowchart of the fourth embodiment.

FIG. 6 is a timing chart of a conventional fluorescent lamp lighting device.

[Explanation of symbols]

 1 Switching Element 2 Light Control Sensor 3 Control Microcomputer Section 4 Fluorescent Lamp Lighting Circuit DB Diode Bridge FL Fluorescent Lamp L Fluorescent Lamp Lighting Current Limiting Inductance Q Transistor T Inverter Transformer

Claims (6)

[Claims] 1. A fluorescent lamp lighting means for turning on / off power supply to the fluorescent lamp, a light amount detecting means for detecting a light emission amount of the fluorescent lamp, and a detected value of the light amount detecting means being inputted to the fluorescent lamp. A control means for determining a ratio of on time and off time of power application to the fluorescent lamp and outputting an on / off signal of power application to the fluorescent lamp lighting means to control the fluorescent lamp to a predetermined constant light amount value. A fluorescent lamp lighting device, wherein the control means is within a predetermined time when the fluorescent lamp is turned on,
An on / off signal with a constant ratio of on time and off time of power supply is output to the fluorescent lamp lighting means irrespective of the detection value of the light quantity detection means, and the light quantity detection means after the predetermined time at the lighting start ends. A fluorescent lamp lighting device, which outputs to the fluorescent lamp lighting means an on / off signal in which a ratio of an on time and an off time of power application to the fluorescent lamp is determined based on the detection value. 2. The fluorescent lamp lighting device according to claim 1, wherein the control unit is configured to detect when the detection value of the light amount detection unit is equal to or larger than a predetermined light amount value within a predetermined time when the fluorescent lamp is turned on. Is an on-off signal that determines the ratio of the on-time and off-time of power application to the fluorescent lamp based on the detection value of the light amount detection means after finishing the output of the on-off signal with a constant ratio of on-time and off-time during output. A fluorescent lamp lighting device, which outputs to the fluorescent lamp lighting means. 3. The fluorescent lamp lighting device according to claim 1 or 2, wherein the control means outputs an ON / OFF signal in which a ratio of ON time and OFF time is constant, and a first predetermined time at lighting start. When the detection value of the light amount detecting means is equal to or smaller than the predetermined light amount at the end, the ON / OFF signal having a constant ratio of ON time and OFF time of power supply is continuously supplied within the second predetermined time regardless of the detection value of the light amount detecting means. After the end of the first predetermined time when the output value to the fluorescent lamp lighting means and the detection value of the light quantity detection means is equal to or more than a predetermined light quantity, or after the end of the second predetermined time, A fluorescent lamp lighting device, which outputs to the fluorescent lamp lighting means an on / off signal in which a ratio of an on time and an off time of power application to the fluorescent lamp is determined based on a detection value of the light quantity detecting means. 4. The fluorescent lamp lighting device according to any one of claims 1 to 3, wherein the control means controls the on-time and off-time of power application to the fluorescent lamp based on the detection value of the light amount detection means. During the output period of the ON / OFF signal determining the ratio of the above to the fluorescent lamp lighting means, when the detection value of the light amount detection means becomes equal to or less than a predetermined value, a signal to stop the lighting of the fluorescent lamp is output to the fluorescent lamp lighting means. A fluorescent lamp lighting device characterized by the above. 5. An image forming apparatus, which irradiates an image forming object with a fluorescent lamp whose lighting is controlled by the fluorescent lamp lighting device according to claim 1, and outputs an image to a recording medium. apparatus. 6. The image forming apparatus according to claim 5, wherein:
An image forming apparatus, characterized in that, after the predetermined period of time when the lighting is started, when the detection value of the light quantity detecting means is equal to or less than the predetermined light quantity, the lighting of the fluorescent lamp is interrupted and an error message is displayed.