JP2003257682A - Lighting confirming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine accurately and quickly whether an element for a light source of a reading device works properly. <P>SOLUTION: From an input power supply 21, the power is given to an inverter 23 through a current measuring circuit 22 to light up a cold cathode tube 24, and the load current in the on condition is fed to a resistance in the current measuring circuit 22, and the voltage on the load side of the resistance is led out from a terminal 26 as a measuring output current, and when this load side voltage of the resistance is below a given value (the output current being over the specified value), a determination is passed that the cold cathode tube 24 is on, and when over the given value, it is determined that the cold cathode tube 24 has gone out. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting confirmation method for an element used as a light source or the like.

[0002]

2. Description of the Related Art In an image forming apparatus such as a facsimile machine, a copying machine, and a multifunctional machine having multiple functions such as a fax function and a copying function, a cold cathode tube or an LED is used as a light source for illuminating and reading a document. Has been. In the recording unit, a halogen lamp is used as a heat source for thermally fixing the toner transferred onto the paper. In order to confirm whether or not these elements are properly turned on, conventionally, in reading a document, a CCD output signal when a cold cathode tube or an LED is turned on is used. Or
For fixing, the halogen lamp is turned on for a predetermined time, and it is determined that the temperature rise is normal when the temperature rises to a predetermined value.

[0003]

SUMMARY OF THE INVENTION The conventional CCD described above.
The way to see the output signal of is, even if the CCD itself is broken,
There is a problem that it is determined that the light source is defective. Also,
Regarding fixing, since the halogen lamp is turned on and a predetermined time until the temperature rises is waited, there is a problem that it takes time before it can be determined to be normal.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a lighting confirmation method capable of accurately and quickly determining whether a device is right or wrong.

[0005]

A lighting confirmation method of the present invention is a method for confirming lighting of an element that is turned on / off depending on whether or not power is supplied, and a method for checking whether or not a driving voltage is applied to the element after the element is turned on. The flowing current is measured, and if the measured current is a predetermined value or more, it is determined that the element is normal.

In the lighting confirmation method of the present invention, for example, a resistor is inserted between the lines to which the drive voltage is applied, and the current is measured by the voltage of one terminal of the resistor. It should be separated from the voltage.

In the lighting confirmation method of the present invention,
When the element is a cold cathode fluorescent lamp, the cold cathode fluorescent lamp is turned on by applying a driving voltage through an inverter, and it is determined whether the cold cathode fluorescent lamp is normal based on the current flowing through the inverter. Good to do.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a block diagram showing the configuration of a facsimile apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the facsimile apparatus of this embodiment has an NCU 1, a MODEM 2, and a ROM 3
, RAM 4, image memory 5, MPU 6, display unit 7, operation unit 8, image reading unit 9, and CODEC 10.
A printer 11 and a bus 12. NCU
Reference numeral 1 controls the connection with the telephone line 13 and sends out the telephone number (= corresponding dial signal) of the other party,
And a function for detecting an incoming call. Modem 2
Is an ITU (International Telecommunication Union) -T recommendation T.M. 30 based on the facsimile transmission control procedure according to V.30. 17,
V. 27 ter, V.I. The transmission data is modulated and the reception data is demodulated according to 29 or the like. The ROM 3 stores a program for controlling the entire device. The RAM 4 temporarily stores various information regarding the facsimile device. The image memory 5 temporarily stores the received image data and the image data read by the image reading unit 9. MPU6 is
According to the program stored in the ROM 3, it controls each unit constituting the device. The display unit 7 displays various information such as the operating state of the device and a transfer time zone display. The operation unit 8 includes a ten-key pad, a one-touch key, a start key, and other keys. The image reading unit 9 reads the image data on the document and outputs black and white binary image data. The image reading unit 9 includes a light source circuit for illuminating the image surface.

The CODEC 10 encodes image data to be transmitted and decodes the received image data. The printer 11 is composed of an electrophotographic printer, and records the image data of the document read by the image reading unit 9 on a recording paper in the received image data and the copy operation. The printer 11 is equipped with a halogen lamp for fixing. However, the hardware configuration of the facsimile apparatus of the embodiment shown here is not particularly new, and the circuit configuration itself is already well known. The novel characteristic feature of the facsimile apparatus of this embodiment lies in the light source circuit constituting the image reading unit 9, as will be described later.

FIG. 2 is a block diagram showing a light source circuit of the image reading section 9. This light source circuit has an input power source 21
A current measuring circuit 22, an inverter 23, and a cold cathode tube 24 which is a light source.

When the cold cathode tube 24 is turned on, a driving voltage of 24 V is supplied from the input power source 21 to the inverter 23 via the current measuring circuit 22, and the inverter 23 causes the cold cathode tube 2 to operate.
4 is turned on. When the cold-cathode tube 24 is turned on, a current of 0.57 A flows in the current measuring circuit 22 as a current during load. On the other hand, when the cold-cathode tube 24 is cut off, 0.06 A flows as a no-load current into the current measuring circuit 22. By deriving this measured current as a measured output current from the terminal 26, it is possible to determine whether or not the cold cathode fluorescent lamp 24 is turned on from the change in the measured output current. In this circuit, by applying a lighting control signal to the terminal 25, the inverter 23 operates to light the cold cathode tube 24.

FIG. 3 is a circuit diagram showing the inside of the current measuring circuit 22 more specifically. The current measuring circuit 22 includes a changeover switch 31 and a variable resistor 32. The common terminal a of the changeover switch 31 is connected to the + 24V input end of the input power source, the changeover terminal b is connected to the input end of the inverter, and the other changeover terminal c of the changeover switch 31 is connected to one end of the variable resistor 32. ing.

The other end of the variable resistor 32 is connected to the switching terminal b and is also connected to the measurement output current lead-out terminal 26.

Normally, the changeover switch 31 is turned on to the changeover terminal b side, and the voltage of 24V from the input power source 21 is applied to the cold cathode tube 24 via the inverter 23.
The cold cathode tube 24 is driven and turned on. When a switching control signal is input to the changeover switch 31 from the terminal 27 while the lighting control signal is being applied in order to confirm the presence or absence of lighting, the changeover switch 31 is turned on to the changeover terminal c side and the load current is changed. Flowing through the variable resistor 32, the voltage at the derivation terminal 26 for the measurement output current drops significantly. This voltage is A
By taking in the MUP 6 via the / D converter, the lighting of the cold cathode tube 24 can be confirmed. If the cold-cathode tube 24 is cut off, the load current is small and therefore the voltage drop at the variable resistor 32 is small, and the voltage at the derivation terminal 26 of the measurement output current is little changed. You can judge.

Next, the light source out check process at the time of reading an image in the facsimile apparatus of the embodiment will be described with reference to the flow chart shown in FIG. First, when an image reading command is input in step ST1, the process proceeds to step ST2. In step ST2, the cold cathode tube 24 is turned off.
N The cold cathode tube 24 is turned on by turning on the lighting control signal. Then, step S
Move to T3.

In step ST3, the switching control signal is turned on. As a result, the changeover switch 31 is turned on to the changeover terminal c side, and the load current flows through the variable resistor 32. Then, the process proceeds to step ST4. In step ST4, the load-side terminal voltage of the variable resistor 32 is derived from the terminal 26, and the voltage is measured (measured output current). Then, it transfers to step ST5. In step ST5, the switching control signal is turned off. As a result, the changeover switch 31 is returned to the original side of the changeover terminal b. Then, the process proceeds to step ST6.

In step ST6, it is determined whether or not the measured voltage is below a predetermined value. If the value is equal to or less than the predetermined value, the cold cathode tube 24 is on and the process proceeds to step ST7.
On the other hand, if the measured voltage is not less than the predetermined value, the cold cathode fluorescent lamp 24
Has expired, and the process proceeds to step ST9.

In step ST9, the cold cathode tube burnout is displayed, and the process ends. In step ST7, image reading is executed. When the image reading is completed, the process proceeds to step ST8. In step ST8, the cold cathode tubes 24 are turned off, and the process ends.

In the above embodiment, the lighting element is a cold cathode tube, but it may be an LED light source. In the case of LEDs, no inverter is needed. The present invention can also be applied to the confirmation of the lighting of the halogen lamp of the fixing device in the recording unit.

Although the detected voltage is input to the A / D port of the MPU, an A / D converter may be used up to the MPU, or the result of analog determination made by the comparator may be taken into the MPU.

Further, in the above embodiment, the case where the invention is applied to the light source circuit of the image reading section of the facsimile apparatus has been described, but the present invention can be widely applied to confirmation of lighting of lighting elements of other electronic devices.

[0023]

According to the present invention, after the element is turned on, the current flowing with the drive voltage applied to the element is measured, and if the measured current is a predetermined value or more, it is determined that the element is normal. The current that flows when the element is lit
Since the quality of the element is determined, it is possible to confirm the lighting surely and quickly. Further, by cutting off the resistance for converting the current into the voltage and measuring it after the lighting is confirmed, it is possible to avoid unnecessary current flowing during lighting and increase in power consumption. The present invention can also be applied to a cold cathode tube that lights up via an inverter.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a facsimile apparatus in which the present invention is implemented.

FIG. 2 is a block diagram showing a light source circuit included in an image reading unit of the facsimile apparatus.

FIG. 3 is a circuit diagram showing an internal connection of a current measuring circuit which constitutes the light source circuit.

FIG. 4 is a flowchart illustrating a light source out check process at the time of image reading of the facsimile apparatus according to the embodiment.

[Explanation of symbols]

21 Input power 22 Current measurement circuit 23 Inverter 24 Cold cathode tubes 25 Lighting control signal terminal 26 Measurement output current derivation terminal 27 Switch control signal terminal 31 Changeover switch 32 variable resistance

Claims (3)

[Claims] 1. A method for confirming lighting of an element that is turned on / off depending on whether or not electricity is applied, wherein after the element is turned on, a current flowing in a state where a drive voltage is applied to the element is measured, and the measured current is a predetermined value or more. if there is,
A lighting confirmation method characterized by determining that an element is normal. 2. A resistor is inserted between the lines for applying the driving voltage, the current is measured by the voltage of one terminal of the resistor, and after it is judged to be normal, the resistor is disconnected from the driving voltage. The lighting confirmation method according to claim 1. 3. The element is a cold-cathode tube, and the cold-cathode tube is turned on by applying a driving voltage through an inverter, and whether the cold-cathode tube is normal or not is determined based on a current flowing through the inverter. The lighting confirmation method according to claim 1 or 2, characterized by making a determination.