JPH06318010A - Fixing temperature control method - Google Patents

Abstract

PURPOSE:To prevent waiting time for printing from getting long, and to make the efficiency of copying work is made higher by switching and controlling fixing reload temperature in accordance with each paper supply part. CONSTITUTION:The fixing reload temperature is controlled in accordance with the difference of the length of a feeding path, for example, from the paper supply port of each paper supply part to a fixing unit, corresponding to each paper supply part. Namely, since heating time becomes long when the length of the feeding path is long, the reload temperature is set to be low. In which stage out of two paper supply stages 1 and 2 the paper is supplied is checked(A). When a signal showing the paper supply stage 2 is outputted(C), the fixing reload temperature is set to a flag for setting low. When the signal is not outputted(B), the flag for setting low is reset and a flag for setting high is set. Data for setting fixing reload are compared with the present temperature of a fixing roller(G), and when the present temperature attains the reload temperature, the display of the acceptance of a printing key on a control panel is turned on(H), and when it does not attain the reload temperature, a fixing heater is turned on(I).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control method in a heat fixing section in an image forming apparatus such as a facsimile, a laser printer and a copying machine.

[0002]

2. Description of the Related Art FIG. 1 shows a main part of an electrophotographic copying machine. The photosensitive drum 1 having a two-layer structure of a conductive support and a photoconductive layer rotates in the direction of the arrow, and its surface is uniformly charged by the charger 2. An image is projected on the surface of the drum 1 through the optical means 3, and an electrostatic image is formed on the surface of the drum 1 by the charging and the projection. Next, the photosensitive drum 1 is developed by the developing device 4, and the developed image is transferred to any one of the paper feeding units 6 and 7 at a predetermined position in the transfer unit 5.
It is transferred onto the paper conveyed from Nos. 8 and 9. After the transfer, the sheet is charged by the separation charging device, is heated and fixed by the fixing device 11 while being transported by the transport belt 10, and is transported by the discharge roller 12 onto the tray outside the device. On the other hand, the entire surface of the photosensitive drum 1 is exposed and the charge is removed, and then the cleaning device 13 removes the residual developer to prepare for the next copying cycle.

As a fixing device of this image forming apparatus, a heat roller fixing device having a structure in which a fixing roller having a heater incorporated therein and a pressure roller are combined has been conventionally known.

In order to control the temperature of the fixing device of such a mode, generally, the temperature control is performed while alternately feeding and non-feeding the heater with a reference temperature (fixing temperature) necessary for performing the fixing operation. A so-called ON-OFF control method and, for example, as disclosed in Japanese Utility Model Publication No. 53-50442, the pulse width or pulse density of the pulse signal for controlling the energization of the heater is proportionally changed as it approaches the fixing temperature. There is a so-called proportional control system.

In order to make up for the disadvantages of each of these methods, for example, in Japanese Unexamined Patent Publication (Kokai) No. 58-42079, a thermal fixing device is linearly raised to a proportional start point by heating by energizing a heater, and then proportionally. A control method is also known in which the thermal equilibrium is controlled to control the transition and maintenance of the fixing temperature required for the fixing operation.

In any case, in the heat roller fixing device, the fixing roller is maintained at a certain set temperature when the machine is on standby, and the sheet sent according to the copy start signal is gripped between the pair of fixing rollers. Heat is applied to fuse and fix the toner on the paper.

In the fixing operation, the heat of the fixing roller is taken by the paper. Therefore, if continuous fixing is performed, it is expected that the temperature of the fixing roller will continue to drop and eventually fall below the fixable temperature. Particularly, in recent years, as the printing speed has increased, the amount of heat absorbed per unit time during the fixing operation has increased, and therefore there is a large difference in the amount of heat absorbed during standby. In particular, the fixing roller itself, which plays a cushioning role by achieving thermal equilibrium with the heater (heat source), has become smaller in response to the downsizing of the entire apparatus, and the heat storage heat capacity thereof has significantly decreased accordingly. Therefore, this tendency is remarkable when a copying operation is performed using a large-sized paper.

When the fixing roller temperature falls below the fixable temperature due to continuous fixing, copying cannot be performed and the mechanical operation must be stopped while the fixing temperature is restored to the set temperature. In order to eliminate such temperature recovery time, it is conceivable to increase the power applied to the heater, but doing so may increase the power consumption of the image forming apparatus as a whole and may even render the general household power supply unusable. is there.

Therefore, in order to extend the continuous fixing time while suppressing the increase in power consumption as much as possible, JP-A-60-16987.
In JP-A-7, a standby temperature (first set temperature) at which fixing is possible and a fixing execution temperature (second set temperature) higher than that are set, and control is performed from the standby temperature to the fixing start temperature by a copy command signal. Is proposed. In that embodiment, when the print button is pressed or the number of sheets is set,
The control temperature is changed from the standby temperature to the fixing start temperature which is 5 to 10 ° C. higher. Further, it is also controlled so that the set temperature returns to the standby temperature when a certain time has elapsed after the copying process is completed.

The idea of setting the temperature of the fixing unit in two stages is also disclosed in Japanese Patent Laid-Open No. 4-186377. The purpose of this is to prevent wasteful heating and long print waiting time.The temperature of the heating source is controlled to fall below the set temperature during standby, and paper is fed during operation. According to the instruction, the temperature is raised again to the set temperature at which fixing is possible. In this case, the temperature of the fixing roller in the standby state is lower than the fixing property ensuring temperature, and the temperature of the heating source is set within the time from the start of paper feeding by the paper feeding instruction until the paper reaches the fixing unit. The temperature is rapidly raised to the set temperature.

In these control methods, a preheating mode or the like is provided so that the set temperature can be arbitrarily switched.

[0012]

However, even in the case of such a structure that switches the temperature of the fixing portion,
Conventionally, when various factors adversely affect the fixability, such as when using the maximum size paper or continuous copying, the paper feed is started by the paper feed instruction and the paper reaches the fixing unit. The reload temperature, that is, the print key acceptance temperature, which is the temperature at which copying can be started, is set so that the fixing property is still ensured by the heating within the time up to. That is, the reload set temperature itself is always fixed, the energy required for starting the heater from cold is constant, and it is considerably high.

However, the fixing device is further heated from the reload temperature by the time the paper is fed by the paper feeding instruction and before the paper reaches the fixing portion, which is apparent from the configuration of FIG. As described above, when the image forming apparatus includes a plurality of paper feeding units, the plurality of paper feeding units 6 and 7,
As is clear from the figure, 8 and 9 are common transport rollers 1
The transport path lengths up to 4 are different.

Further, the turn paper feeding units 7, 8 and 9 have to be provided with a curved conveying path unlike the linear paper feeding unit 6 because of their mounting positions, so that the characteristics of the sheets that can be accommodated are different. That is, for example, thick paper such as 135 kg paper is not suitable for conveyance in a curved conveyance path, and thus image formation is performed using the linear paper feed section. There are many known paper feed methods for cut sheets, and the FRR paper feed method using a reverse roller and the corner claw method are typical ones. In particular, the corner claw method is used for loading sheets to be stacked. Since the paper is separated by using the elasticity of the paper when caught by the corner claws arranged corresponding to the corners of the paper, it is possible to separate the paper having a thickness of about 45 to 90 kg. , Not suitable for feeding thick paper. Further, such a thick paper requires a larger amount of heat at the time of fixing.
FIG. 2 shows the relationship among the sheet feeding property, the transporting property, and the fixing property depending on the change in the paper thickness. Therefore, depending on the paper feeding style of the paper feeding unit,
Paper that can be fed may be limited.

In the conventional method in which the reload temperature is fixed, even when the sheet advances along the conveying path having the shortest conveying path length, or when the sheet requiring the largest amount of heat for fixing is used, Since the predetermined fixing property can be secured by further heating from the reloading temperature, the fixing unit is heated more than necessary if the transport path length is longer. Alternatively, in the case of fixing on thin paper, an excessive amount of heat is applied to the paper. In other words, if the transport path length is relatively long, or if it is clear that only thin paper will be fixed, the reload temperature is set too high, wasting energy, and the fixing rise time is also unsatisfactory. It can be said that it has taken a long time as necessary. Similarly, when the paper is preheated by a moisture-proof heater or the like, a small amount of heat should be given to the fixing unit.

From the above, it is not necessary to set the reload temperatures detected at the same point to be the same in any case in order to reach the temperature for securing the fixing property. Then, the subject of this invention is made | formed in view of the above-mentioned point, and it reduces wasteful start-up energy, prevents that a print waiting time becomes long, and promotes the efficiency of copy work, and actual fixing It is an object of the present invention to provide a fixing temperature control method for maintaining the fixing property ensuring temperature when the above is performed.

[0017]

In order to solve this problem, according to the present invention, in a fixing temperature control method for an image forming apparatus having a plurality of paper feed units, a fixing reload temperature is set according to each paper feed unit. Switch control.

It is preferable to switch and control the fixing reload temperature in accordance with the difference in the transport path length from the sheet feeding port of the sheet feeding section to the fixing unit.

When a plurality of paper feeding units are composed of a turn paper feeding unit and a straight paper feeding unit, when the straight paper feeding unit is selected, the fixing reload temperature is set to be higher than that when the turn paper feeding unit is selected. Is preferred.

The fixing / reloading temperature may be switched and controlled depending on the paper feeding method, for example, the corner claw separation method.

In the image forming apparatus provided with the moistureproof heater, it is preferable to control the switching of the fixing reload temperature depending on the presence / absence of the moistureproof heater in each sheet feeding section.

Further, it is more convenient if the fixing reload temperature is switched and controlled according to the ON time of the moistureproof heater.

[0023]

EXAMPLES The details of the present invention will be explained based on the examples shown in the drawings, but it goes without saying that the present invention is not limited to these.

In the temperature control flow of FIG. 3, after the power is turned on, first, the paper is fed in any one of the two paper feed stages 1 and 2 provided in the image forming apparatus. Is it checked? That is, it is checked whether or not a signal is output so that the paper feed stage 2 is in the paper feed state (A). If a signal is output (C), the fixing reload temperature is set in the low setting flag. If there is no signal (B),
The low setting flag is reset, that is, the fixing reload temperature is set to the high setting flag. If the low setting flag is set, low setting data (for example, 145 ° C.) is set in the accumulator (E). If the high setting flag is set, the high setting data (for example, 165 ° C.) is set in the accumulator (F).

When the temperature based on these setting data is A, the contents of the accumulator, that is, the setting data of the fixing reload and the current temperature of the fixing roller are compared (G), and the current fixing roller surface temperature is set by the accumulator. If it is higher than the data, that is, if the reload temperature has been reached, turn on the print key reception display on the operation panel.
(H), fixing possible temperature data is set in the B register (M). If the reload temperature has not been reached, the fixing heater is turned on (I), and the current temperature and the setting data A are compared again.

Further, the current surface temperature of the fixing roller is compared with the contents of the B register, that is, the fixable temperature B (for example, 185 ° C.) (J). If the current temperature is higher than the fixable temperature, the fixing heater is turned on. The fixing heater is turned off (K), and if the current temperature is low, the fixing heater is turned on (L).

Further, for example, when there are a plurality of paper feed stages and there is a difference in the transport path length to the fixing unit of the paper feed stages,
That is, if there is a difference in the time from the start of paper feeding to the arrival of the paper at the fixing unit, heating is performed in the fixing unit even while the paper is being carried through the carrying path. When the temperature is raised to the fixable temperature, the heating time can be used to reduce the start-up energy. That is, when the transport path length is longer,
Since the heating time becomes long, the reload temperature can be set low.

In FIG. 4, the graph line I shows the temperature change when the paper is conveyed through the long conveyance path,
The reload temperature is set low. Even if the reload temperature is low, the transport path is long and heating occurs during that time, so
By the time the sheet reaches the fixing unit, the unit has reached the fixable temperature. Also graph line II
Shows the temperature change when the paper is conveyed through a short conveyance path, and since the reload temperature is set to a high value, even if the heating time becomes short, at the time when the paper reaches the fixing unit, Will reach the fixable temperature.

The control operation will be described with reference to the flowchart of FIG.

After the power is turned on, it is first detected whether or not the paper is fed from the paper feed port having a short conveyance path (A). When the conveyance path is short (B), the fixing reload temperature is set in the high setting flag. If the conveyance path is not short (C), the fixing reload temperature is set in the low setting flag. If the low setting flag is set, the low setting data is set in the accumulator (E). If the high setting flag is set, the high setting data is set in the accumulator (F).

The contents of the accumulator, that is, the set temperature A of the fixing reload and the current temperature of the fixing roller are compared.
(G) If the current surface temperature of the fixing roller is higher than the set temperature of the accumulator, that is, if the reload temperature has been reached, the print key acceptance display is turned on on the operation panel (H) and fixing is performed. The possible temperature data is set in the B register (M). If the reload temperature has not been reached,
The fixing heater is turned on (I), and the current temperature and the set temperature are compared again.

Further, the current surface temperature of the fixing roller is compared with the fixable temperature B (J). If the current temperature is higher than the fixable temperature, the fixing heater is turned off (K), and if the current temperature is low. , The fixing heater is turned on (L).

Further, as described above, since the thick paper is difficult to feed by using the turn paper feeding unit because of its transportability, it is conveyed by using the straight paper feeding unit. Since the heat quantity of the fixing roller that is taken away by is also different, when the turn paper feeding unit that only conveys thin paper is selected,
The fixing reload temperature / fixable temperature can be set lower.

The control operation in this case will be described with reference to the flowchart of FIG.

After the power is turned on, it is first detected whether or not the turn sheet feeding section is selected (A). If the turn sheet feeding unit is not selected (B), the fixing reload temperature is set in the high setting flag, and the fixable temperature is also set in the high setting flag. When the turn paper feeding unit is selected (C), the fixing reload temperature is set in the low setting flag, and the fixable temperature is also set in the low setting flag. If the low setting flag is set, the low setting data is set in the accumulator (E). If the high setting flag is set, the high setting data is set in the accumulator (F).

The contents of the accumulator, that is, the set temperature A of the fixing reload and the current temperature of the fixing roller are compared.
(G) If the current surface temperature of the fixing roller is higher than the set temperature of the accumulator, that is, if the reload temperature has been reached, the print key acceptance display is turned on on the operation panel (H) and fixing is performed. If the possible temperature is set in the low setting flag, the low data of the fixable temperature is set in the B register (M '). If the fixable temperature is not set to the low setting flag, the high data of the fixable temperature is set to the B register (M ″). If the reload temperature has not been reached, the fixing heater is turned on (I), and the current temperature and the set temperature are compared again.

Further, the current surface temperature of the fixing roller is compared with the fixable temperature B (J). If the current temperature is higher than the fixable temperature, the fixing heater is turned off (K), and if the current temperature is low. , The fixing heater is turned on (L).

Further, in the paper feed stage adopting the corner claw separation system, it is not suitable for separating thick paper as described above, and therefore only thin paper is separated and conveyed. Therefore, when the corner claw separation type sheet feeding unit that conveys only thin paper is selected, the fixing reload temperature / fixable temperature can be set to a lower value.

The control operation in this case will be described with reference to the flowchart of FIG.

After the power is turned on, it is first detected whether or not the sheet feeding unit having the corner claw is selected.
(A). If the corner claw separation feed section is not selected
(B) The fixing reload temperature is set in the high setting flag, and the fixable temperature is also set in the high setting flag. When the corner claw separation sheet feeding unit is selected (C), the fixing reload temperature is set in the low setting flag, and the fixable temperature is also set in the low setting flag. If the low setting flag is set, the low setting data is set in the accumulator (E). If the high setting flag is set, the high setting data is set in the accumulator (F).

The contents of the accumulator, that is, the set temperature A of the fixing reload and the current temperature of the fixing roller are compared.
(G) If the current surface temperature of the fixing roller is higher than the set temperature of the accumulator, that is, if the reload temperature has been reached, the print key acceptance display is turned on on the operation panel (H) and fixing is performed. If the possible temperature is set in the low setting flag, the low data of the fixable temperature is set in the B register (M '). If the fixable temperature is not set to the low setting flag, the high data of the fixable temperature is set to the B register (M ″). If the reload temperature has not been reached, the fixing heater is turned on (I), and the current temperature and the set temperature are compared again.

Furthermore, the current surface temperature of the fixing roller is compared with the fixable temperature B (J). If the current temperature is higher than the fixable temperature, the fixing heater is turned off (K), and if the current temperature is low. , The fixing heater is turned on (L).

Further, in the paper feeding operation, the humidity of the paper influences the separation of the stacked paper. Therefore, in order to adjust the humidity to an appropriate range, a moistureproof heater is often attached. When the toner is warmed, the fixing can be performed even if the temperature of the fixing unit is lowered as shown in FIG. That is, when the paper feed unit including the moisture-proof heater is selected, the fixing reload temperature / fixable temperature can be set to be low.

The control operation in this case will be described with reference to the flowchart of FIG.

After the power is turned on, it is first detected whether or not the paper feed unit having the moistureproof heater is selected.
(A). When the paper feed unit with the moisture-proof heater is not selected (B), the fixing reload temperature is set in the high setting flag and the fixable temperature is also set in the high setting flag.
If the paper feed unit with moisture-proof heater is selected (C),
The fixing reload temperature is set in the low setting flag, and the feasible temperature is also set in the low setting flag. If the low setting flag is set, the low setting data is set in the accumulator (E). If the high setting flag is set, set the high setting data in the accumulator
(F).

The contents of the accumulator, that is, the set temperature A of the fixing reload and the current temperature of the fixing roller are compared.
(G) If the current surface temperature of the fixing roller is higher than the set temperature of the accumulator, that is, if the reload temperature has been reached, the print key acceptance display is turned on on the operation panel (H) and fixing is performed. If the possible temperature is set in the low setting flag, the low data of the fixable temperature is set in the B register (M '). If the fixable temperature is not set to the low setting flag, the high data of the fixable temperature is set to the B register (M ″). If the reload temperature has not been reached, the fixing heater is turned on (I), and the current temperature and the set temperature are compared again.

Further, the current fixing roller surface temperature is compared with the fixable temperature B (J). If the current temperature is higher than the fixable temperature, the fixing heater is turned off (K), and if the current temperature is low. , The fixing heater is turned on (L).

Even when the moisture-proof heater is attached, it is shortly after the moisture-proof heater is turned on,
When a new sheet is loaded, the sheet itself may not be sufficiently warmed. That is, the temperature change of the paper by the moistureproof heater is as shown in FIG.
Therefore, the fixing reload temperature / fixable temperature can be switched depending on whether or not the ON time of the moistureproof heater is long. Further, it is also possible to predict the temperature rise of the paper from the ON time of the heater and make the fixing reload temperature / fixable temperature variable in multiple stages based on that, so that the rising energy can be minimized while securing the fixing property. .

The control operation for switching the fixing reload temperature / fixable temperature depending on whether or not the ON time of the moistureproof heater is long will be described with reference to the flowchart of FIG.

After the power is turned on, first the moisture-proof heater O
It is detected whether N time exceeds a predetermined time (A). If the predetermined time has not been exceeded (B), the fixing reload temperature is set in the high setting flag, and the fixable temperature is also set in the high setting flag. When it has been turned on for a long time beyond the predetermined time (C), the fixing reload temperature is set to the low setting flag, and the fixable temperature is also set to the low setting flag. If low setting flab is set, set low setting data to accumulator
(E). If the high setting flag is set, the high setting data is set in the accumulator (F).

The contents of the accumulator, that is, the set temperature A of the fixing reload and the current temperature of the fixing roller are compared.
(G) If the current surface temperature of the fixing roller is higher than the set temperature of the accumulator, that is, if the reload temperature has been reached, the print key acceptance display is turned on on the operation panel (H) and fixing is performed. If the possible temperature is set in the low setting flag, the low data of the fixable temperature is set in the B register (M '). If the fixable temperature is not set to the low setting flag, the high data of the fixable temperature is set to the B register (M ″). If the reload temperature has not been reached, the fixing heater is turned on (I), and the current temperature and the set temperature are compared again.

Further, the current surface temperature of the fixing roller is compared with the fixable temperature B (J). If the current temperature is higher than the fixable temperature, the fixing heater is turned off (K), and if the current temperature is low. , The fixing heater is turned on (L).

As described above, when the reload temperature is switched depending on the difference in transport path length and the presence / absence of the moistureproof heater,
As shown in FIG. 12, the CPU, which has received a signal from the operation unit or the detection sensor of the moisture-proof heater, issues an instruction to a fixing heater control plate (not shown) according to the reload set temperature to control the heater of the fixing unit to be turned on and off. To do.

[0054]

According to the fixing temperature control of the first aspect of the present invention, since the fixing reload temperature is switched and controlled according to each sheet feeding section of the plurality of sheet feeding sections, the worst condition for the fixing property can be obtained. Saves energy by shortening the fixing start-up time, unlike the constant setting of a high reload temperature.
It is possible to improve the efficiency of copy operations.

According to the fixing temperature control of the second aspect of the present invention, the fixing reload temperature is switched and controlled according to the difference in the transport path length from the sheet feeding port of the sheet feeding section to the fixing unit. The effect of the fixing temperature control is specifically realized in the difference in the transport distance from the sheet feeding unit to the fixing unit, and thus in the difference in the additional heating time in the heater of the fixing unit.

According to the fixing temperature control according to the third aspect of the present invention, when the plurality of sheet feeding units include the turn sheet feeding unit and the linear sheet feeding unit, when the linear sheet feeding unit is selected, The fixing reload temperature is set to a temperature higher than that when the turn paper feeding unit is selected. According to the fixing temperature control according to the invention described in claim 4, the fixing reload temperature depends on the paper feeding method, for example, the corner claw separation method. Since the switching control is performed, the effect of the fixing temperature control according to the first aspect can be specifically realized according to the thickness of the paper.

According to the fixing temperature control of the fifth aspect of the invention, in the image forming apparatus having the moisture-proof heater,
Since the fixing reload temperature is switched and controlled depending on whether or not the moistureproof heater is attached to each sheet feeding unit, the effect of the fixing temperature control according to the first aspect can be specifically realized according to the temperature of the sheet. Particularly, when the fixing reload temperature is switched and controlled according to the ON time of the moistureproof heater as described in claim 6, the effect of the fixing temperature control of claim 1 can be more effectively realized.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main part of an electrophotographic copying apparatus.

FIG. 2 is a graph showing a relationship among a paper feeding property, a transporting property, and a fixing property depending on a change in paper thickness.

FIG. 3 shows an operation flow of fixing temperature control according to the present invention.

FIG. 4 is a graph showing a temperature change in a fixing unit due to a difference in length of a transport path.

FIG. 5 shows an operation flow of fixing temperature control based on a transport path length.

FIG. 6 shows an operation flow of fixing temperature control depending on whether or not it is a turn sheet feeding unit.

FIG. 7 is a flowchart showing an operation flow of fixing temperature control depending on whether a corner claw separation type sheet feeding unit is used.

FIG. 8 is a graph showing changes in fixable temperature depending on the presence or absence of a moisture-proof heater.

FIG. 9 shows an operation flow of fixing temperature control depending on the presence or absence of a moistureproof heater.

FIG. 10 is a graph showing a temperature change of a sheet by a moistureproof heater.

FIG. 11 shows an operation flow of fixing temperature control depending on the length of ON time of the moistureproof heater.

FIG. 12 is a diagram showing a structural relationship of a control mechanism according to the present invention.

[Explanation of symbols]

 1 Photosensitive Drum 2 Charging Device 3 Optical Means 4 Developing Device 5 Transfer Part 10 Conveyor Belt 11 Fixing Device 12 Paper Ejection Roller 13 Cleaning Device

Claims (6)

[Claims] 1. A fixing temperature control method for an image forming apparatus having a plurality of sheet feeding units, wherein a fixing reload temperature is switched and controlled according to each sheet feeding unit. 2. The fixing temperature control method according to claim 1, wherein the fixing reload temperature is switched and controlled in accordance with a difference in transport path length from the sheet feeding port of the sheet feeding section to the fixing unit. 3. When the plurality of sheet feeding units include a turn sheet feeding unit and a straight sheet feeding unit, when the straight sheet feeding unit is selected, the fixing reload is performed at a higher temperature than when the turn sheet feeding unit is selected. The fixing temperature control method according to claim 1, wherein the temperature is set. 4. The fixing temperature control method according to claim 1, wherein the fixing reload temperature is switched and controlled according to a difference in a paper feeding method. 5. The fixing temperature control method according to claim 1, wherein when the image forming apparatus includes a moisture proof heater, the fixing reload temperature is switched and controlled depending on whether or not the moisture proof heater is attached to each sheet feeding unit. . 6. The fixing reload temperature is switched and controlled according to the ON time of the moistureproof heater.
The method for controlling the fixing temperature according to item 4.