JP2002040849A - Image forming device, control method for fixing device, and carbon heater lamp for fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device, a control method for fixing device, and a carbon heater lamp for fixing device, which easily cope with different supply voltages to suppress a rush current. SOLUTION: In the image forming device, a heat source of the fixing device consists of the carbon heater lamp where plural carbon heater lamps or heating bodies are arranged in a common lamp pipe stock, and plural carbon heater lamps or heating bodies are so constituted that they can be switched to the series connection state or the parallel connection state. Plural heating bodies are arranged in the common lamp pipe stock, and individual heating bodies are connected in series and are used with a power source having a voltage of p (volt), and they are connected in parallel and are used with a power source having a voltage of 2p (volt).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with a fixing device using a carbon heater lamp whose heating element is made of a carbon material as a heating source, a control method of the fixing device, and a carbon heater lamp for the fixing device.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus of an electrophotographic system, a heating roller and a pressure roller arranged so as to be pressed against the heating roller are used to fix a toner image on one surface of a recording material. The provided fixing device is widely used.

Conventionally, in a certain type of fixing device, a plurality of heater lamps such as halogen lamps are provided as a heating source of a heating roller. In such a fixing device, even when recording materials having different sizes are used, the temperature distribution of the heating roller can be made uniform in a preset temperature range (hereinafter, referred to as “set temperature range”). This makes it easy to reduce the rise time of the temperature of the heating roller.

However, in the above-described fixing device, the halogen lamp as a heating source has a small electric resistance at room temperature. As shown in FIG. 7, the inrush power at the start of energization is large, and a large voltage fluctuation occurs due to the inrush current. As a result, a large flicker (human) is caused to lighting equipment connected to the halogen lamp and a common power supply system. This causes a problem of "flickering" felt by the user. The flicker increases as the input power to the halogen lamp increases, but the degree of the flicker needs to be suppressed within a specified range (flicker standard). For example, in the image forming apparatus, the flicker value (short-term flicker value) during the copying operation defined by the voltage fluctuation amount is 1 or less, and the flicker value (long-term flicker value) during the standby mode specified by the frequency of occurrence of the voltage fluctuation. (Flicker value) is required to be 0.65 or less.

On the other hand, a commercial AC power supply has a voltage of 100 volts in Japan, but has a voltage of 200 volts in some countries.
Because of the use of volt power, there are only two
It is necessary to make specifications according to the power supply voltage of 00 volt.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made based on the above circumstances, and its object is to provide:
An image forming apparatus which can easily cope with a case where power supply voltages are different, can normally operate a heating source of an intended heating roller, and can suppress an inrush current due to the start of energization; and An object of the present invention is to provide a carbon heater lamp for a fixing device. It is another object of the present invention to provide a control method of a fixing device which can easily cope with a case where power supply voltages are different. Another object of the present invention is to provide a carbon heater lamp for a fixing device which can be easily applied even when the power supply voltage is different.

[0007]

An image forming apparatus according to the present invention is an image forming apparatus having a fixing device for heating and fixing a toner image, wherein a heating source of the fixing device is a heating element made of carbon material. And a plurality of carbon heater lamps having the following. Further, the heating source of the fixing device has two identical carbon heater lamps, and the two carbon heater lamps are configured to be switchable between a series connection state and a parallel connection state. When p (volt) is used, it is used in a parallel connection state, and when the power supply voltage is 2 p (volt), it is used in a series connection state.

In addition, an automatic voltage discriminating means for detecting a power supply voltage is provided, and a connection state of the carbon heater lamp is switched between a parallel connection state and a series connection state according to the detection result. Further, the fixing device includes a heating roller, and two carbon heater lamps are disposed inside the heating roller.

A method of controlling a fixing device according to the present invention comprises a heating roller, and a heating source of the heating roller is constituted by two carbon heater lamps having a heating element made of carbon material. A method wherein when the input voltage to the heating source is 2p (volts), the two carbon heater lamps are connected in series and their lighting state is on-off controlled, and Is p (volts).
The temperature control of the heating roller is performed by controlling the lighting state of the two carbon heater lamps in a parallel connection state.

An image forming apparatus according to the present invention is an image forming apparatus including a fixing device that heats and fixes a toner image, wherein a heating source of the fixing device is a lamp element having a plurality of heating elements each made of a carbon material. It is characterized by being constituted by a carbon heater lamp provided in the tube. The heating source of the fixing device is made of a carbon material.
It is characterized in that it has a carbon heater lamp in which two identical heating elements are disposed in a common lamp element tube, and the two heating elements are configured to be independently energized and controllable.

An image forming apparatus according to the present invention is an image forming apparatus including a fixing device for heating and fixing a toner image, wherein two identical heating elements each made of a carbon material are used in common as a heating source of the fixing device. The two heating elements are configured to be switchable between a series connection state and a parallel connection state, and the power supply voltage is p (volt). Is used in a parallel connection state, and when the power supply voltage is 2p (volt), it is used in a series connection state.
Also provided is an automatic voltage discriminating means for detecting a power supply voltage,
According to the detection result, the connection state of the carbon heater lamp is switched between a parallel connection state and a series connection state. Further, the fixing device includes a heating roller, and a carbon heater lamp in which two heating elements are disposed in a common lamp base tube is disposed inside the heating roller.

A method of controlling a fixing device according to the present invention includes a heating roller, wherein a heating source of the heating roller is a carbon source in which two heating elements each made of a carbon material are arranged in a common lamp tube. A method of controlling a fixing device including a heater lamp, wherein when the input voltage to the heating source is 2p (volt), the two heating elements are connected in series to control their lighting state. Further, when the input voltage is p (volt), the temperature control of the heating roller is performed by controlling the lighting state of the two heating elements in a parallel connection state. I do.

In the carbon heater lamp for a fixing device according to the present invention, a plurality of heating elements each made of a carbon material are disposed in a common lamp base tube, and the heating elements are connected in series to generate a voltage of p ( Volts), and each heating element is connected in parallel, and the voltage is 2p (volts). The plurality of heating elements are the same or different from each other.

[0014]

According to the control method of the image forming apparatus and the fixing device of the present invention, two identical carbon heater lamps can be switched between a series connection state and a parallel connection state according to the power supply voltage. In a carbon heater lamp in which two identical heating elements are provided in a common lamp tube, the heating elements can be switched between a series connection state and a parallel connection state in accordance with a power supply voltage, so that different voltages are used. In the case of using the power source, the carbon heater lamp as the heating source can be normally operated only by switching the connection state. Moreover, the inrush current associated with the start of energization of the carbon heater lamp having a heating element made of carbon material is substantially zero or sufficiently small, so that the peak value of the inrush current is suppressed.

Further, according to the carbon heater lamp for a fixing device of the present invention, a limited heating roller is provided by using a carbon heater lamp in which two identical heating elements made of carbon material are provided in a common lamp base tube. It is easy to provide a large number of heating elements in the space inside, and it is possible to precisely control the temperature of the heating roller corresponding to each operation mode of the image forming apparatus by controlling the individual heating elements on and off independently. Becomes The heating element of the carbon heater lamp can be adapted to a power supply of a different voltage by changing the connection state.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing an example of a main part of the configuration of the image forming apparatus of the present invention. The image forming apparatus includes a drum-shaped photoreceptor 11 on which an electrostatic image is formed, a charging unit 12 for charging the photoreceptor 11, and a toner image formed by visualizing the electrostatic image formed on the photoreceptor 11. A developing unit 13 for forming an image, a transfer unit 14 for transferring a toner image formed on the photoconductor 11 to a recording material, a separating unit 15 for separating a recording material that is in close contact with the photoconductor 11, A fixing device 20 for fixing the transferred toner image. In this figure, 16 is a transport mechanism, 17 is a cleaning unit, and 18 is a transport path.

The fixing device 20 includes a heating roller 21 having a heating source 23 therein, which is disposed in contact with the surface of the recording material onto which the toner image has been transferred (in FIG. 1, for example, the upper surface of the recording material). The heating roller 21 and the pressure roller 22 form a nip portion, that is, a fixing region (not shown).

The heating roller 21 has a coating layer 211 made of, for example, a fluororesin formed on the outer peripheral surface of the metal core 212.
A heater lamp as the heating source 23 is disposed inside the core metal 212. As the fluororesin constituting the coating layer 211, for example, PTFE (polytetrafluoroethylene) or PFA (tetrafluoroethylene-perfluoroalkylvinyl ether copolymer) is exemplified. The material forming the metal core 212 is not particularly limited, but may be a metal such as aluminum, iron, copper, or an alloy thereof.

The pressure roller 22 has a coating layer 221 made of an elastic material formed on the outer peripheral surface of a metal core 222. The elastic body constituting the coating layer 221 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber, and sponge rubbers. It is preferable to use a suitable silicone rubber and silicone sponge rubber. The material constituting the metal core 222 is not particularly limited, and examples thereof include metals such as aluminum, iron, and copper or alloys thereof.

FIG. 2 shows a heating source 2 in the heating roller 21.
3, two identical carbon heater lamps 42
It is a circuit block diagram which shows an example of the lighting circuit of 42a, 42b.
In this lighting circuit, the carbon heater lamp 42
a and 42b correspond to an input power of 100 volts.
Through a switch SW5 to a common AC power supply 41 such as a commercial power supply. In particular,
The carbon heater lamp 42b and the switch element SW5 are connected in series to the AC power supply 41 to form a closed circuit, and the connection point a1 between the AC power supply 41 and the carbon heater lamp 42b, the switch element SW5 and the AC power supply 41 A series circuit of the switch element SW2 and the switch element SW3 is connected between the switch element SW3 and the connection point a2 between the switch element SW2 and the switch element SW3, and the connection between the carbon heater lamp 42b and the switch element SW5. The carbon heater lamp 42a and the switch element SW1 are connected in series between the point a6 and a connection point a5 between the carbon heater lamp 42a and the switch element SW1, and a connection point a4 between the connection point a3 and the switch element SW5. Is connected to the switch element SW4.

Each of the switch elements SW1 to SW5 is a switch element having a control terminal such as a triac, and is turned on or off by a control signal issued from a switch element control means (not shown). Each of them is controlled independently, and the lighting state of the carbon heater lamps 42a and 42b can be independently controlled on-off.

In such a lighting circuit, the switch elements SW1, SW2, and SW5 are turned on, and both the switch elements SW3 and SW4 are turned off, so that the carbon heater lamps 42a and 42b are turned off.
Are connected in parallel, the switch elements SW1 and SW3 are both turned on, and the other switch elements SW2, SW4, and SW5 are turned off, so that the carbon heater lamps 42a and 42b are connected in series. You. Further, only the switch element SW5 is turned on, and the other switch elements SW1 to SW4 are turned off, so that only the carbon heater lamp 42b is turned on alone, and both the switch element SW2 and the switch element SW4 are turned on. State and the other switch element S
By turning off W1, SW3 and SW5, only the carbon heater lamp 42a is turned on independently.

The carbon heater lamps 42a and 42b are
Each of the heating elements 42 made of carbon material extends in a straight tubular enclosure made of, for example, quartz glass, and extends along the pipe axis.
1a and 421b are provided.
Both ends of a and 421b are held by the power supply portions provided at both ends of the sealing body to form a power supply structure and are hermetically sealed. Then, for example, argon gas is sealed in the sealed body. As such carbon heater lamps 42a and 42b, for example, those having an input power of 100 to 900 W can be used, and the total input power of the entire heating source 23 is 200 to 1
It may be 800 W.

In this image forming apparatus, the AC power supply 4
1 is provided with automatic voltage discriminating means (not shown) for automatically detecting the voltage, and the power supply voltage is detected by the automatic voltage discriminating means. The elements SW1 to SW5 are controlled to switch between the parallel connection state and the series connection state in the carbon heater lamps 42a and 42b.

For example, when the power supply voltage is 100 volts, the switch elements SW1, SW2, SW5
Is turned on, and the switch elements SW3 and SW4 are controlled to be turned off, thereby achieving a parallel connection state in which the carbon heater lamps 42a and 42b are connected in parallel. When the power supply voltage is 200 volts, switch elements SW1 and SW3 are turned on, and switch elements SW2 and SW3 are turned on.
4. Control is performed so that SW5 is turned off, whereby a series connection state in which the carbon heater lamps 42a and 42b are connected in series is achieved.

As a result, regardless of the power supply voltage,
Since a voltage of 100 volts is applied to the heating elements 44a and 44b in each of the carbon heater lamps 42a and 42b, they can be operated normally.

In the image forming apparatus, the carbon heater lamps 42a and 42b are connected to the switch elements SW1 to SW
5 is controlled to perform on-off control, so that the temperature of the heating roller 21 is controlled within a proper set temperature range.

Here, the carbon heater lamp 42
a and 42b may be replaced by a carbon heater lamp 43 described later. Specifically, the heating element 44a of the carbon heater lamp 43 is used instead of the heating element 43a, and the carbon heater lamp 43 is used instead of the heating element 43b. The heating element 44b may be connected.

According to the above-described method of controlling the image forming apparatus and the fixing device, in the heating source 23 of the heating roller, the power supply voltage is detected by the automatic voltage discriminating means, and the switch elements SW1 to SW5 are controlled according to the detection result. Since both of these carbon heater lamps 42a and 42b are configured to be switchable between a series connection state and a parallel connection state, p (volt) and 2p (volt) are used.
In any of the cases where AC power supplies having different voltages are used, the connection state is simply automatically switched and each of the carbon heater lamps 42a and 42b can be normally operated.

The carbon heater lamps 42a, 42
b has a large resistance even at room temperature,
Even when energization is started at room temperature, the generated rush current is substantially zero or extremely small as shown in FIG. Therefore, even when the heating source 23 at room temperature is energized, the rush current in the entire image forming apparatus is suppressed.

In the above image forming apparatus, the switch between the parallel connection state and the series connection state of the carbon heater lamps is achieved by operating a switch in accordance with the power supply voltage used by the user, for example, instead of the automatic voltage determining means. You may. In addition, for products for export, the manufacturer may perform the switching in advance in accordance with the commercial AC power supply voltage of the export destination area.

FIG. 4 is an explanatory view showing an example of a carbon heater lamp for a fixing device in which a heating element made of a plurality of carbon materials is provided inside a common lamp tube. The carbon heater lamp 43 for the fixing device is composed of two identical heating elements 44a and 44b made of a carbon material so as to extend in the tube axis direction, respectively, in a lamp tube E which is a straight tubular sealing body made of quartz glass. The two ends of each of the two heating elements 44a and 44b are held by power supply sections provided at both ends of the sealing body to form a power supply structure and are hermetically sealed. ing. Then, for example, argon gas is sealed in the sealed body. Each heating element 4
4a and 44b are for 100 volts, for example.

As such a carbon heater lamp 43 for the fixing device, for example, one having a total input power of a plurality of heating elements of 200 to 1800 W can be used.
Further, each of the heating elements 44a and 44b preferably has an input power of 100 to 900W. In the above-described carbon heater lamp 43 for the fixing device, the heating elements 44a and 44b are connected, for example, in such a manner that they can be individually controlled to be energized. , The temperature of the heating roller can be controlled precisely.

The above carbon heater lamp 43 can be configured such that its lighting state can be switched between a series connection state and a parallel connection state by controlling the above-mentioned switch element. The same operation and effect as those obtained when two carbon heater lamps each having one heating element are used can be obtained. Also, for example, when the power supply voltage is 100 volts, they are connected in a parallel connection state as shown in FIG. 5, while when the power supply voltage is 200 volts,
They may be connected in a series connection state as shown in FIG. In these connection circuits, the heating elements 44a,
The temperature of the heating roller can be controlled by on-off control of 4b.

As described above, the two heating elements 44a, 44
According to the carbon heater lamp for the fixing device having the b in the common lamp tube E, a large number of heating elements can be provided even in a limited space in the heating roller 21 in the fixing device 20. As a result, a sufficient amount of heat can be obtained, and as a result, an excellent toner image can be heated and fixed. When two heating elements provided in a common lamp tube are the same, the voltage becomes p
(Volts) connected in parallel when used with a power supply,
When used with a 2p (volt) power supply, they are connected in series, so that the carbon heater lamp can be operated normally. As a result, the same carbon heater lamp can be used, for example, in regions having different power supply voltages. Can operate normally even when used with

Further, when the heating elements provided in the common lamp tube have different input powers, the heating elements having different input powers depend on the amount of heat required for heating the heating roller. Is appropriately selected, and the lighting state of the selected heating element is turned on / off, so that more precise temperature control of the heating roller can be performed.

Various modifications may be made to the carbon heater lamp for the fixing device as needed. For example, a configuration may be adopted in which two or more heating elements are disposed in a common lamp element, and the two heating elements are connected to each other at one end in the lamp element, and From the tube, one point from the connection point connecting these two heating elements
A configuration in which the number of lead wires is extended may be employed.

[0038]

According to the control method of the image forming apparatus and the fixing device of the present invention, two identical carbon heater lamps can be switched between a series connection state and a parallel connection state according to the power supply voltage. In addition, in a carbon heater lamp in which two identical heating elements are provided in a common lamp tube, the heating elements can be switched between a series connection state and a parallel connection state according to a power supply voltage. Even when power supplies of different voltages are used, the carbon heater lamp, which is the heating source, can be normally operated only by switching the connection state. Moreover, the inrush current associated with the start of energization of the carbon heater lamp having a heating element made of carbon material is substantially zero or sufficiently small, so that the peak value of the inrush current is suppressed.

According to the carbon heater lamp for a fixing device of the present invention, a limited heating roller is provided by using a carbon heater lamp in which two identical heating elements made of carbon material are provided in a common lamp base tube. It is easy to provide a large number of heating elements in the space inside, and it is possible to precisely control the temperature of the heating roller corresponding to each operation mode of the image forming apparatus by controlling the individual heating elements on and off independently. Becomes The heating element of the carbon heater lamp can be adapted to a power supply of a different voltage by changing the connection state.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an example of a main part of a configuration of an image forming apparatus of the present invention.

FIG. 2 is a circuit diagram showing an example of a lighting circuit of a carbon heater lamp constituting a heating source in a heating roller.

FIG. 3 is an explanatory diagram showing current characteristics of a carbon heater lamp at room temperature.

FIG. 4 is an explanatory view showing an example of a carbon heater lamp for a fixing device in which a heating element made of a plurality of carbon materials is provided inside a lamp tube constituting a heating source in a heating roller.

FIG. 5 is a circuit diagram showing an example of a lighting circuit for a carbon heater lamp for a fixing device.

FIG. 6 is a circuit diagram showing another example of a lighting circuit for a carbon heater lamp for a fixing device.

FIG. 7 is an explanatory diagram showing current characteristics of a halogen lamp at room temperature.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 photoconductor 12 charging unit 13 developing unit 14 transfer unit 15 separation unit 16 transport mechanism 17 cleaning unit 18 transport path 20 fixing device 21 heating roller 211 coating layer 212 core metal 22 pressure roller 221 coating layer 222 core metal 23 heating source 41 AC power supplies 42a, 42b Carbon heater lamps 421a, 421b Heating elements 43 Carbon heater lamps 44a, 44b Heating elements SW1 to SW5 Switch elements a1 to a6 Connection point E Lamp base tube

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Watanabe 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Shinobu Kishi 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Soma Umin 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H033 AA41 BA25 BA27 BA30 BB18 BB21 CA07 CA23 CA27 CA48 3K058 AA53 BA18 CA03 CB02

Claims (14)

[Claims] 1. An image forming apparatus including a fixing device for heating and fixing a toner image, wherein a heating source of the fixing device is constituted by a plurality of carbon heater lamps each having a heating element made of a carbon material. Characteristic image forming apparatus. 2. An image forming apparatus having a fixing device for heating and fixing a toner image, wherein a heating source of the fixing device has two identical carbon heater lamps, and the two carbon heater lamps are connected in series. State and a parallel connection state. When the power supply voltage is p (volt), the connection state is a parallel connection state.
When the power supply voltage is 2p (volt), the image forming apparatus is used in a series connection state. 3. An automatic voltage discriminating means for detecting a power supply voltage, wherein a connection state of the carbon heater lamp is switched between a parallel connection state and a series connection state according to the detection result. The image forming apparatus according to claim 2. 4. The fixing device includes a heating roller.
The image forming apparatus according to claim 1, wherein two carbon heater lamps are disposed inside the heating roller. 5. A control method for a fixing device comprising a heating roller, wherein a heating source of the heating roller is constituted by two carbon heater lamps having a heating element made of a carbon material. When the voltage is 2p (volts), the two carbon heater lamps are connected in series, and the lighting state of the two carbon heater lamps is controlled by turning on and off.
Further, when the input voltage is p (volt), the temperature control of the heating roller is performed by controlling the lighting state of the two carbon heater lamps in a parallel connection state. Control method of fixing device. 6. An image forming apparatus comprising a fixing device for heating and fixing a toner image, wherein a heating source of the fixing device is a carbon having a plurality of heating elements each made of a carbon material disposed in a common lamp tube. An image forming apparatus comprising a heater lamp. 7. An image forming apparatus including a fixing device for heating and fixing a toner image, wherein a heating source of the fixing device is such that two identical heating elements each made of a carbon material are disposed in a common lamp tube. An image forming apparatus comprising: a carbon heater lamp; wherein the two heating elements are configured to be independently energized and controllable. 8. An image forming apparatus provided with a fixing device for heating and fixing a toner image, wherein a heating source of the fixing device is made of a carbon material.
A carbon heater lamp in which two identical heating elements are disposed in a common lamp tube, wherein the two heating elements are configured to be switchable between a series connection state and a parallel connection state; Power supply voltage is p (volt)
If the power supply voltage is 2p
(Volt), the image forming apparatus is used in a series connection state. 9. An automatic voltage discriminating means for detecting a power supply voltage, wherein a connection state of the carbon heater lamp is switched between a parallel connection state and a series connection state according to the detection result. An image forming apparatus according to claim 8. 10. The fixing device includes a heating roller,
10. The image forming apparatus according to claim 6, wherein a carbon heater lamp in which two heating elements are disposed in a common lamp tube is disposed inside the heating roller. apparatus. 11. A fixing device comprising a heating roller, wherein a heating source of the heating roller is a carbon heater lamp in which two heating elements each made of a carbon material are disposed in a common lamp tube. In the control method of the device, when the input voltage to the heating source is 2p (volt), by controlling the lighting state of the two heating elements in a series connection state, the input voltage becomes p.
(Volts), the temperature control of the heating roller is performed by controlling the lighting state of the two heating elements in a parallel connection state, thereby controlling the fixing device. 12. A plurality of heating elements each made of a carbon material are disposed in a common lamp base tube. Each of the heating elements is connected in series to be used with a power supply having a voltage of p (volt). A carbon heater lamp for a fixing device, wherein a body is connected in parallel and used with a power supply having a voltage of 2p (volt). 13. The carbon heater lamp according to claim 12, wherein the plurality of heating elements are the same as each other. 14. The carbon heater lamp according to claim 12, wherein the plurality of heating elements are different from each other.