JPS6139075A - Picture recorder - Google Patents

Abstract

PURPOSE:To reduce radiation of heat from a fixing device into a housing as less as possible, to shorten a warm-up time and to suppress the temperature rise in a machine as less as possible even if heat discharging fan is stopped at the time of a power saving mode by arranging heat insulating members on both ends, thermally floating a fixing roller from its supporting body and arranging a heat radiation shielding cover on the periphery of the fixing roller. CONSTITUTION:A curved surface-like reflecting plate 7 having heat reflecting property is arranged adjacently to the periphery of a heat roller 1 over the whole longitudinal direction of the heat roller 1 and a thick cover 8 for preventing heat radiation is tightly adhered to the whole projected surface of the reflecting plate 7 to suppress useless heat radiation from the reflecting plate 7. A reflecting plate 9 and a cover 10 are also arranged on the press roller 2 side so as to cover the great part of the periphery of the press roller 2. The arrangement of these reflecting plates 7, 9 and covers 8, 10 makes it possible to reduce useless heat consumption lost from the heat roller 1 and the press roller 2. Since the heat roller 1 is thermally independent of the machine body and frame bodies 13, 13' by heat insulating sleeves 11, 11' and heat resisting gears 14, 14', heat radiation to the outside of the fixing device through these units is extremely reduced.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an image recording apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus using toner, and particularly to a method for fixing a toner image on a recording sheet (transfer paper, etc.). This invention relates to improvements to roller-type heat fixing devices.

[Background of the invention]

For example, in a conventional heat fixing device of this type for an electrophotographic copying machine, when the power is turned on, the heater of the fixing device is energized and rapidly heated until it reaches a fixable temperature, thereby warming up the roller. When the temperature reaches a predetermined temperature of 1 degree and the warm-up ends, the temperature is thereafter controlled to maintain that temperature. However, conventionally, even in the ready state (copying operation standby state, ie, standby state) in which no copying operation is performed, the heater is energized to control its temperature. That is, after the power is turned on, the heater of the fixing device is continuously energized until the power is turned off again.

For this reason, wasted power consumption will increase significantly.
There was a problem with the temperature inside the aircraft rising significantly. This type of electronic copying machine is equipped with a cooling fan to prevent the temperature inside the machine from rising. Conventionally, the fan is operated when the power is turned on, and the fan is turned on until the power is turned off again. It is designed so that it does not stop working. For this reason, there are problems in that noise is generated in the ready state, and wasteful power consumption further increases.

In view of this, Japanese Patent Laid-Open No. 56-92558 proposed stopping the fan and turning off the fixing heater if no copy is made within a certain period of time after entering the standby state, but the next copy signal will not be input. Since the fixing heater remains off until the next copy is made, there is a long wait time and it is difficult to use.

Therefore, we have provided a power-saving switch that can turn off the heat exhaust fan during standby, and by turning on this power-saving switch, the heat exhaust fan is stopped and the surface temperature of the fixing roller is set to a predetermined setting temperature (the first temperature) for fixing. Set temperature TL
) It has been considered to adjust the temperature at a second set temperature T2 lower than the temperature T2.

(Patent Application No. 58-26664). At this second set temperature,
is a temperature defined as a safe use area where electrical and mechanical components can perform their original functions without suffering thermal deterioration due to temperature rise inside the machine even if the heat exhaust fan is stopped. By providing the power saving switch in this way, it is possible to eliminate noise caused by the heat exhaust fan during standby and to save energy.

However, after the power-saving switch is released, the second set temperature T.

The wait time for the temperature to return to the first set temperature T8 from Even if the temperature is adjusted at the second set temperature T, which is lower than the first set temperature T-1 that allows fixing, there is a concern that the temperature inside the machine will rise excessively.

It is true that according to the above proposal, fan noise can be prevented, but the set temperature during standby or power saving cannot be made so low, and the energy savings are only minimal. This is because most of the heat consumed during standby is wasted. In other words, the temperature of other parts of the device that do not require heating will be significantly increased.
On the contrary, it requires a high temperature setting (standby, power saving).

The present invention provides a rational and highly practical device that can expand energy saving to a practical advantageous range, shorten the time until fixing is possible, and lower the temperature rise inside the machine.

[Purpose of the invention]

In a toner-using image recording device having this type of heat roller type fixing device, the heat dissipation from the fixing device is minimized to save energy, and even if the cooling fan is stopped when saving power, there is no need to worry about internal temperature rising. thing.

[Summary of the invention]

The present invention provides an image recording apparatus equipped with a pair of fixing rollers for heating and fixing an unfixed toner image onto a recording material, and a cooling means for sucking exhaust heat or outside air to prevent temperature rise inside the machine body. A heat-insulating cover member provided close to the periphery of the two pairs of fixing rollers, a heat insulating member provided at both ends of the first roller that is mainly heated among the pair of fixing rollers, and a heat-insulating cover member provided near the periphery of the two pairs of fixing rollers; means for controlling the temperature of the first roller to either a first set temperature or a second set temperature lower than the first set temperature, and while the skeleton temperature control means maintains the first roller at the second set temperature, and means for prohibiting the operation of the cooling means.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention in which a toner image T formed by electrophotography is fixed on plain paper P by a thermal fixing device.

A heating roller 1 has a heating heater 3 such as a Halodan heater inside, and rotates in the direction of the arrow in response to driving force from a drive motor (not shown). 2 is heater 3 for low heating
A pressure roller with a built-in roller presses against the heating roller 1 and rotates by sliding.

Heating-1 21 is a roller having a heat-resistant discrete resin layer of 20 to 80 μm thick, such as tetrafluoroethylene resin, on the outer peripheral surface of a hollow roller core made of metal such as aluminum, stainless steel, or copper. The pressure row 22 is rotatably supported on the pairing 15.15'. The pressure roller 2 is brought into pressure contact with the heating roller 1 by a known pressure means at least during fixing.
, a relatively thick layer of elastic material such as silicone rubber, furan rubber, fluorosilicone rubber, etc. is provided on the outer peripheral surface of a metal roller core. This configuration has a pressure contact area d with the heating roller 1.
The purpose is to ensure that A temperature sensing element 4 such as a thermistor or thermocouple is disposed in contact with the outer circumferential surface of the heating roller 1, and its detection signal is guided to a control means to be described later. Temperature (
By controlling the output of the heater 3 or its applied voltage, etc.), the toner image melting temperature is maintained at a first set temperature (described below).

Reference numeral 6 denotes a cleaning member for removing foreign matter such as offset toner and paper powder adhering to the heating roller surface from the roller surface, and a cleaning web 6 made of a heat-resistant nonwoven fabric such as Nomex or Himeron is used. The cleaning web 6□ has an elastic pressing roller 6;
It is in contact with the heating roller 1 due to this. Also, this sea urchin web □ is moved by a driven winding roller 66 (not shown) from the supply roller 6 □ to change its contact position little by little, so that a new surface of the cleaning web 6 □ always reaches the heating roller 21 . comes into contact with. This web 6□ moves on the rollers 64 interposed after the pressing row 263, and moves to the supply row 2.
It is reversed to the 6□ side and wound around the winding roller 66 with the front and back sides reversed. Furthermore, if the cleaning web 6 is impregnated with an anti-offset liquid such as dimethyl silicone oil, the cleaning effect can be further enhanced.

7 is a curved reflector having heat reflection properties, and heating roller 1
It is provided near the periphery of the heating row 21 over the entire longitudinal direction of the heating row 21. Further, the reflecting plate 7 is a pressing row 26 on the circumferential surface of the heating roller 1. It has a width so as to cover the space between the position and the entrance opening for the transfer paper P. A thick bracket 8 for preventing heat radiation is provided in close contact with the entire convex surface of the reflecting plate 7 to prevent wasteful radiation of heat from the reflecting plate 7.

Reference numeral 16 denotes a casing member on the upper side of the fixing device, which surrounds the cleaning member 6, the reflection plate 7, the cover 8, and the temperature sensing element 4. The temperature sensing portion of the temperature sensing element 4 is located closer to the row 21 than the reflecting plate 7 is.

On the other hand, a reflecting plate 9 similar to the reflecting plate 7 is also provided on the pressure roller 2 side.
A cover 10 similar to the cover 8 is provided so as to cover most of the surface of the pressure row 22. It is effective to make the surface of the reflecting plate facing the roller a metal surface (mirror surface).

By providing these reflective plates 7, 9 and covers 8, 10, it is possible to reduce the heat wasted from the surfaces of the heating row 21 and the pressure row 22, and also to improve the temperature measurement performance of the temperature sensing element 4. can be stabilized. Also, heating low 2
Temperature control for the set temperature of 1 can be stabilized and power consumption can be reduced.

A guide plate 22 guides the transfer paper P toward the heating roller 1, and is provided close to the heating roller 21 so as to be located between one end of each of the reflecting plates 7 and 9.

Reference numeral 24 denotes a support plate that supports the pressure roller, and the pressure roller 2 is brought into pressure contact with the heating roller 1 by the screw 23.

A transfer paper P made of plain paper having an unfixed toner image T is held and conveyed between heating and pressure rollers 22, and then transferred to the rollers 21,
The toner image T is fixed by applying heat at a surface temperature of 20, and is then ejected from the apparatus while being held between paper ejection rows 220 and 21.

On the discharge port side of the heating roller 1, a plurality of separating claws 5 are provided in contact with the roller surface along the roller axis direction in order to reliably separate the transfer paper P from the heating roller 1.

Also, there is a separation claw 5 on the discharge port side of the pressure roller 2. is low 22
is placed in contact with the surface of the

The separation claw 5 is connected to the support plate 1 in a separated state from the casing member 16.
8, and the separating claw 51 is also held by the support plate 18□ which is spaced apart from the casing member 17 on the lower side of the fixing device.

The casing member 17 is spaced apart from the reflector 9 and cover 10 of the pressure roller 2 and is provided so as to cover them.

The reflective plates 7 and 9 are preferably made of a metal with a glossy surface, such as an aluminum plate with a polished surface, a copper plate, or an iron plate with a surface treatment such as Cr plating. The shape of the reflecting plates 7 and 9 is preferably one having a curvature concentric with the circumferential surface of the row 2, and the thickness thereof is preferably relatively thin.

The covers 8 and 1o are preferably made of glass wool, rock wool, ceramic fiber, or a foam such as phenol foam or epoxy foam, or are made of a composite material.

Next, using FIG. 2 showing the x-x' cross section 9 of FIG. 1,
The configuration of the end portion of the heating roller 1 will be described in detail.

11 and 11' are rotating shafts 11 at both ends of the heating row 21, respectively.
The heat-resistant sleeves are respectively fitted to the +IZ and are in contact with the bearings 12 and 12' mounted on the frames 13 and 13' of the fixing device, respectively.

Heat-resistant gears 14 and 14' are fitted onto the rotating shaft 11+1'1 of the heating roller 1, respectively, and transmit driving force thereto. The heat-resistant gear 14' meshes with another drive transmission gear 25, receives the driving force from the drive source M, and rotates together with the heating row 21. The heat-resistant gear 14 includes the gear 26□ of the manual knob 26.
are engaged and manual driving force is transmitted.

Since the heat-resistant gears 14 and 14' are made of a heat-insulating material, the heating row 21 is connected to the gears 14.1.
Heat is not dissipated to other drive transmission members such as gears through the gears 4'. This gear improves the heat retention property of the heating roller l.

Furthermore, the heat-resistant sleeves 11, 11' are also heat-insulating materials, and prevent heat loss due to heat transfer from the ends of the heating roller 1 to the bearings 12, 12' and the frames 13, 13'. I'm here. Therefore, the heat loss from the end of the heating roller 1 can be reduced by the heat-resistant gears 14, 14', and can be further significantly reduced or almost eliminated by the addition of the heat-resistant sleeves 11, 11'. can.

Generally, the heat-resistant gears 14, 14' are often provided with a number of other drive transmission members in conjunction with each other. Therefore, heat loss occupies the majority in such a drive system. In the embodiments described above, heat loss to the drive system can be reduced or eliminated, so thermal efficiency can be greatly improved and power consumption can be reduced.

In addition, in the above embodiment, heat-resistant sleeves 11, 11' are used in addition to heat-resistant gears 14, 14', so heat loss from the roller ends to frames 13, 13' can be prevented, and thermal efficiency can be further improved. You can improve. In the above example, heating row 2
Although heat-resistant and heat-insulating parts are provided on both ends of 1,
It is sufficient that at least a heat insulating portion is provided between the row 21 and the side receiving the driving force of the member that transmits the driving force to the row 21. The above-mentioned heat-resistant sleeves include those that are heat-insulating materials such as polyimide, polyamideimide, polyamide, PP5 (polyphenylene sulfide), PBT (yJ? butylene terephthalate) resin, phenol resin, etc.
Alternatively, it is preferable to use a material made of a heat-insulating material made of this type of mixed material. The gears 14 and 14' may be made of a heat-resistant material with good heat insulation properties, such as polyimide, polyamide-imide, pps, modified phenol, tetrafluoroethylene, and a reinforced optical fiber material. preferable.

As mentioned above, the heating roller 1 includes a heat-resistant sleeve 11,
11' and heat-resistant gears 14 and 14', the fixing device is thermally isolated from the main body of the machine and the frames 13 and 13', and the amount of heat transmitted through these to the outside of the fixing device is extremely small.

Returning to FIG. 1 again, numeral 30 is a cooling fan for reducing the high temperature inside the electrophotographic apparatus, and either sucks outside air into the apparatus or exhausts heat to the outside of the apparatus. Reference numeral 34 denotes an air hole provided in the outer wall of the device, through which outside air or internal air or gas passes. Reference numeral 31 denotes a means for controlling the operation of the cooling means 30, which stops operating at least when the power saving mode is selected by the power saving mode selector 32, and operates when recording an image. Reference numeral 33 denotes a heating control means 33, which mainly controls the energization of the heater 3 in order to heat the heating roller 1 to a predetermined temperature higher than that of the pressure roller 2. The heating control means 33 at least controls the temperature of the heating roller 1 at different set temperatures ('rt,'
rt, (Tl > T!)), the output from the temperature sensing element 4 in contact with the roller 1 is used.

In this example, heating control is performed by lowering the set temperature of the heating roller 1 from the first set temperature T8 suitable for fixing to a lower temperature T2 during the power saving mode 32.

3 and 4 are main circuit diagrams of the means 31, 32, 33, in which R1-R14 are resistors, D1-D4 are diodes, Qlr Q2 rQ6 are converters, Q8. Ql is a transistor, Q4 is 88
, C, is a capacitor, K, ! 35 is a power transformer, 36 is a DC power circuit, 30 is the heat exhaust fan, 37 is a power saving switch, 38 is a main switch, 39
is the temperature fuse. 4 is a thermistor for detecting the temperature of the heating row 21. When the main switch 38 is turned on, power is applied to the heater 3, which is the heat source of the fixing device, via the temperature 7use 39 and the 5SR (Q a ), which is the driver of the heater.

After the main switch is turned on and warm-up is completed, if the power saving switch 37 is not turned on and is in standby mode, the relay □ is not energized and heat is exhausted through the relay 1 contact □-1. Fan 30 is being driven. The temperature of the fixing device is detected by the thermistor 4, and the temperature of the heating roller 1 is set to the first set temperature by controlling the heater 3 of the fixing device by a bridge circuit consisting of a resistor R4, thermistor 4, resistors R7 and R8, and a comparator Q. Control to T□. That is, when the temperature of the heating roller is lower than the set temperature T□, the output of the comparator Q1 is not at a high level, and the transistor Q3 is turned on via the resistor R1°, the diode D8, and the resistor R0.
5SR (Q4) for the heater driver is turned on to supply power to the heater 3, and when the temperature is heated to the set temperature 18 or higher, the output of the con/gulator Q1 is at a low level. By turning off 5SR (Qa), the supply of power to the heater 3 is stopped. In this way, when the power saving switch is in the off state, the temperature of the heating roller 1 is controlled to the set value T1.

When the power saving input switch 37 is turned on, the resistor R1□
The timer composed of IR1□, R83, capacitor c1, and converter t4 converter Q6 starts operating, and the relay is activated until the set time is reached, and the relay is connected to contact 2, and -□ becomes the power saving relay. 1 is energized, and the energization of the heat exhaust fan 30 is stopped by the contact 1-1 of the relay 1, and the outlet of the converter/4 regulator Q□ is lowered by the contact 1-3 of the relay 1/. A bridge circuit consisting of a resistor R4, a thermistor 4, and resistors R8 and R6 and a comparator are used to maintain the temperature of the heating row 21 at a second set temperature T, which is set lower than the first set temperature T□. Q! The heater 3 is controlled by the set temperature T.
, is controlled so that . That is, when the temperature of the heating roller 1 is lower than the set temperature T, the output of the controller Q becomes high level, and the diode D! , the transistor Q3 is turned on via the resistor R9, the heater driver 5SR (Q4) is turned on, and power is supplied to the heater 3. If it is heated to a set temperature of 18 or higher, turn off the
When the output of the 4-rater Q is at a low level, the power supply to the heater 3 is stopped by turning off the 8SR (Q4) for the heater driver. In this way, when the power saving switch is on, that is, in the power saving mode, the temperature of the heating roller 1 is the set temperature T.

controlled by. When the power saving switch is turned off again to cancel the power saving mode, the heating row 21 is controlled to the set temperature Tyu again.

〔Effect of the invention〕

As described above, by not only providing heat insulating members at both ends of the first roller to thermally float the fixing roller from its support structure, but also providing a heat radiation shielding cover around the first roller, it is possible to prevent the fixing device from entering the machine. By minimizing heat dissipation, warm-up time is not only shortened, but even if the heat exhaust fan is stopped during power-saving mode, temperature rise inside the aircraft can be prevented as much as possible. In order to prevent temperature rise, there is no need to set the temperature much lower than the first set temperature T□, which is suitable for fusing, and the wait time after power saving mode is canceled can be shortened.Moreover, less heat is radiated to the outside of the fusing device, resulting in significant energy savings. Contribute. It goes without saying that stopping the heat exhaust fan helps prevent noise.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a longitudinal sectional view thereof, and FIGS. 3 and 4 are circuit diagrams of heating control, power saving selection, and cooling fan drive control of the embodiment. 1... Heating roller, 2... Pressure roller, 3
．． 3'... Heater, 4... Temperature detector,
7.8.9.10...Heat shielding cover, 30...Cooling fan. Figure 1

Claims (1)

[Claims] (1) In an image recording apparatus including a pair of fixing rollers for heating and fixing an unfixed toner image onto a recording material, and a cooling means for sucking exhaust heat or outside air to prevent temperature rise inside the equipment, the above-mentioned A heat-insulating cover member provided close to the periphery of the pair of fixing rollers, a heat insulating member provided at both ends of the first roller that is mainly heated among the pair of fixing rollers, and a first setting suitable for fixing. and means for controlling the temperature of the first roller to either a temperature or a second set temperature lower than the first set temperature, and a means for controlling the temperature of the first roller while the temperature control means maintains the first roller at the second set temperature. An image recording device comprising: means for prohibiting operation of the means.