JP3185912B2 - Thermal fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copier, a facsimile,
The present invention relates to a heat fixing device used for an image forming apparatus such as a printer.

[0002]

2. Description of the Related Art In a heat fixing device, at least two rollers of a rotating upper roller and a lower roller which is pressed and driven by a load against the upper roller and rotate.
And an inner surface heating means for heating at least one of the upper roller and the lower roller from the inside thereof (in addition to this, an outer surface heating means for heating the outside roller from the outside is also provided), and the upper roller By sandwiching the image forming medium between the roller and the lower roller, heat is directly transmitted from the roller to the toner image to fix the toner image on the image forming medium. Conventionally, halogen heaters are often used as the inner surface heating means and the outer surface heating means because of their good responsiveness.

[0003]

However, the halogen heater has a low thermal efficiency, so that the limit of the image processing speed is low. Further, since the resistance value of the halogen heater is low when it is cold, the inrush current is large, and adversely affects other peripheral devices (such as flicker).

Accordingly, it is a first object of the present invention to provide a heat fixing device capable of performing higher-speed image forming processing with the same power consumption.

A second object of the present invention is to provide a heat fixing device in which adverse effects on other peripheral devices are reduced.

[0006]

To achieve the above object, according to an aspect of, a thermal fixing device according to claim 1, in the heat fixing device for heat-fixing the toner image on the image forming medium, the
A heating means provided with a halogen heater provided in the upper roller;
Seeds provided in a lower roller driven by the upper roller
A heater, and the halogen heater and the seed heater.
It is characterized by controlling the motors connected in series .

[0007] The sheathed heater has a higher thermal efficiency than the halogen heater, but has not been used very actively conventionally because of its extremely poor response.
However, by combining the two as described above, it is possible to improve the thermal efficiency with the sheathed heater while ensuring the responsiveness of the halogen heater to a level that does not hinder use. If the power consumption of the halogen heater is appropriately suppressed, the rush current can be reduced.

Also, a halogen heater and a sheath heater
Are connected in series, but the sheathed heater has a high resistance value.
Therefore, by doing this, the inrush current is suppressed.
can do.

[0009]

[0010]

[0011]

Further, a thermal fixing device according to claim 2,
In a heat fixing device that heats and fixes a toner image on an image forming medium, the heating unit heats an upper roller.
Heats a heater and a lower roller driven by the upper roller
And a sheath heater.
Heaters are controlled independently and the power saving mode is selected.
Halogen heater conducts when selected or when small number processing is set
In this case, only the sheath heater is controlled.

[0013] Depending on doing so, the power-saving mode
Since the time when selecting or small number processing setting amount of heat removed but has never come to a good responsiveness is not large, it is possible to cope sufficiently be only a sheath heater. Since the sheathed heater has a small change in the resistance value, even if only the sheathed heater is controlled, there is little possibility of adverse effects such as flicker on other devices as in the case of the halogen heater.

Further, in the heat fixing device according to the fifth aspect,
The heat fixing device according to claim 4, wherein at the time of preheating,
During standby, when the power saving mode is selected, or when decimal processing is set, the halogen heater is not turned on, and only the sheath heater is controlled.

By doing so, the responsiveness is deteriorated, but the thermal efficiency can be further improved. During preheating and during standby, less responsiveness is required than during image formation, and when the power saving mode is selected, the user seeks good thermal efficiency. Nevertheless, since the amount of heat taken is not large, the sheathed heater alone can sufficiently cope. Since the sheathed heater has a small change in the resistance value, even if only the sheathed heater is controlled, there is little possibility of adverse effects such as flicker on other devices as in the case of the halogen heater.

Further, in the heat fixing device according to the third aspect ,
3. The heat fixing device according to claim 2 , wherein the phase control of the halogen heater and the sheath heater is performed.

Further, in the heat fixing device according to the fourth aspect ,
3. The thermal fixing device according to claim 2 , wherein the halogen heater and the sheath heater are current controlled.

As described above, various characteristics can be obtained with respect to the balance between responsiveness and thermal efficiency.
For example, when only the sheathed heater is controlled, all of the predetermined power is consumed by the sheathed heater, and the thermal efficiency can be given the highest priority.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing only a roller portion of a heat fixing device according to an embodiment of the present invention.
Is a rotating upper roller, 2 is driven by an upper roller 1, a rotating lower roller, 3 is a halogen heater, heats the upper roller 1 from the inside thereof, 4 is a sheath heater, and 4 is a seed heater. Heat from. By sandwiching the transfer paper (image forming medium) 5 between the upper roller 1 and the lower roller 2, heat is directly transmitted from the rollers to the toner image 6 on the transfer paper 5 to fix the toner image 6 on the transfer paper 5. I have.

In addition to FIG. 1, as shown in FIG. 2, a lower heater 2 is provided with a sheath heater 4 as a means for heating the lower roller 2 from the outside, or as shown in FIG. 1 is heated from within,
The sheath heater 4 may be of various types, such as one that heats the upper roller 1 from the inside and heats the lower roller 2 from the outside.

The sheath heater 4 is a halogen heater 3
Conventionally, it has not been used very aggressively because of its high thermal efficiency but very poor response. However, by combining the two as described above, it is possible to improve the thermal efficiency with the sheath heater 4 while ensuring the responsiveness of the halogen heater 3 to such an extent that there is no problem in use. Therefore, higher-speed image processing can be performed with the same power consumption. Also, if the power consumption of the halogen heater 3 is appropriately suppressed, the rush current can be reduced. Therefore, adverse effects (such as flicker) on other peripheral devices can be reduced.

Halogen heater 3 and sheath heater 4
FIG. 4 shows a portion of the first control circuit example relating to the present invention.
In the figure, 7 is an AC power supply, 8 is an operation unit for a user to input an instruction, 9 is a temperature sensor for detecting the temperature of the heat fixing device, and 10 is a switch based on a signal from the operation unit 8 or the temperature sensor 9. 11 is a microcomputer that opens and closes 11.

Since the halogen heater 3 and the high-resistance sheathed heater 4 are connected in series, the rush current flowing at the moment when the switch 11 is closed can be considerably suppressed. Therefore, adverse effects (such as flicker) on other peripheral devices can be reduced.

Halogen heater 3 and sheath heater 4
FIG. 5 shows a portion of the second control circuit example relating to the present invention.
In the figure, the same parts as those in the first control circuit example are denoted by the same reference numerals, and description thereof will be omitted.

The halogen heater 3 and the sheath heater 4 are connected in parallel, and the rush current increases as compared with the case where they are connected in series. However, the capacity of the halogen heater 3 can be reduced by sharing the capacity. The rush current can be set considerably smaller than in the case where only the halogen heater 3 is used as in the related art. Therefore, adverse effects (such as flicker) on other peripheral devices can be reduced. In addition, since the current flowing through the halogen heater 3 is not restricted by the sheath heater 4, the responsiveness is improved as compared with the case where the current is controlled by connecting in series.

Halogen heater 3 and sheath heater 4
FIG. 6 shows a portion of the third control circuit example relating to the present invention.
In the figure, the same parts as those in the first and second control circuit examples are denoted by the same reference numerals, and description thereof will be omitted. Switches 12 and 13 are provided so that the halogen heater 3 and the sheath heater 4 can be controlled independently of each other.
The opening and closing is performed by 0.

By doing so, the same effect as in the case of connecting in parallel is obtained, and both the halogen heater 3 and the sheath heater 4 are controlled, or the sheath heater 4 Or can only be controlled.

As an example of a control method in the third control circuit example, at the time of preheating, during standby, when the power saving mode is selected,
Alternatively, when the decimal processing is set, the microcomputer 10 may keep the switch 12 open to keep the halogen heater 3 from conducting, and open and close the switch 13 to control only the sheath heater 4.

By doing so, the responsiveness deteriorates, but the thermal efficiency can be further improved. During preheating and during standby, less responsiveness is required than during image formation, and when the power saving mode is selected, the user seeks good thermal efficiency. Nevertheless, since the amount of heat taken is not large, the sheathed heater alone can sufficiently cope. Since the sheath heater 4 has a small change in the resistance value, even if only the sheath heater 4 is controlled, there is no possibility that other devices such as the flicker may be adversely affected unlike the halogen heater 3.

In addition, as shown in FIG. 7, a phase detector 14 or a current detector 15 is provided in FIG. 6, and the microcomputer 10 controls the phase of each of the halogen heater 3 and the sheath heater 4 according to a signal from these. By controlling the current, the power consumption distribution can be changed.

Thus, for example, when the temperature of the heat fixing device is low, the power consumption of the halogen heater 3 is increased so as not to adversely affect other peripheral devices, and the responsiveness is prioritized. (Within the temperature range), the sheath heater 4 consumes all the predetermined power to give top priority to thermal efficiency, and the halogen heater 3 and the sheath heater 4 evenly consume power in other intermediate temperature ranges. Various properties can be obtained with respect to the balance between performance and thermal efficiency.

[0032]

According to the heat fixing device of the present invention, by combining a halogen heater with good responsiveness and a sheathed heater with good thermal efficiency, it is possible to secure the responsiveness of the halogen heater to the extent that it does not hinder the use of the heater. Heat efficiency can be improved by the heater, and higher-speed image forming processing can be performed with the same power consumption. Also, if the power consumption of the halogen heater is appropriately suppressed, the rush current can be reduced, and adverse effects on other peripheral devices can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing only a roller unit of a heat fixing device according to an embodiment of the present invention.

FIG. 2 is a view showing only a roller portion of a heat fixing device according to another embodiment of the present invention, which is different from FIG. 1;

FIG. 3 is a diagram showing only a roller portion of a heat fixing device according to another embodiment of the present invention, which is different from FIGS.

FIG. 4 is a diagram showing a first control circuit example of a halogen heater 3 and a sheath heater 4.

FIG. 5 is a diagram showing a second control circuit example of the halogen heater 3 and the sheath heater 4.

FIG. 6 is a diagram showing a third control circuit example of the halogen heater 3 and the sheath heater 4.

FIG. 7 is a diagram showing a circuit example in which a phase detector 14 or a current detector 15 is provided in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper roller 2 Lower roller 3 Halogen heater 4 Seed heater 5 Transfer paper (image forming medium) 6 Toner image 7 AC power supply 8 Operation unit 9 Temperature sensor 10 Microcomputer 11, 12, 13 Switch 14 Phase detection circuit 15 Current detection circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (4)

(57) [Claims] An image forming method comprising: fixing a toner image on an image forming medium by heating;
Heat fixing device, A halogen heater in which the heating means is provided in an upper roller
And a roller provided in the lower roller driven by the upper roller.
Heater and the halogen heater and the sheath heater.
Control by connecting heaters in series
Heat fixing device. 2. A method for heating and fixing a toner image on an image forming medium.
Heat fixing device, A halogen heater for heating the upper roller by the heating means;
Seeds heating the lower roller driven by the upper roller
The halogen heater and the sheathed heater.
Control when the power saving mode is selected or
When a number of treatments are set, the halogen heater is not turned on.
A thermostat characterized by controlling only the sheathed heater
Wearing device. 3. The method according to claim 1, wherein the halogen heater and the sheath heater are
3. The heat fixing method according to claim 2, wherein the phase is controlled.
apparatus. 4. The method according to claim 1, wherein the halogen heater and the sheath heater are
The heat fixing according to claim 2, wherein current control is performed.
apparatus.