JP3395812B2 - Temperature control method in fixing device - Google Patents

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 fixing device of an image forming apparatus such as an electrophotographic copying machine.

[0002]

2. Description of the Related Art A fixing device of this type is designed to fix a toner image transferred onto a transfer medium by heating and melting the toner image. -75573 and JP-A-60-8
There is one disclosed in Japanese Patent No. 7377.

[0003]

In the former case of the prior art, the ON / OFF control of the heating lamp is performed in response to the activation of the timer means after the warm-up of the copying machine is completed. In this method, there is a possibility that a temperature shift may occur with respect to the set temperature to be controlled due to changes in the surrounding environment (ambient temperature, voltage fluctuation). Therefore, it is very unstable when the ambient temperature is low,
There is also a risk of defective fixing. In the latter case, a plurality of heating lamps with different electric power are provided in the heating roll, and the heating lamps used for warm-up, standby, and running are used properly, but in this case, a considerable cost increase can be easily predicted. .

The present invention has been made in view of the above, and it is possible to ensure a stable fixing property of the fixing device during the standby of the copy operation, so that the energy saving can be achieved, and the fluctuation of the power supply voltage It is an object of the present invention to provide a temperature control method for a fixing device, which has effects such as prevention of secondary damage.

[0005]

In order to achieve the above object, a temperature control method in a fixing device according to the present invention is such that a heating lamp is turned on and OF by temperature control by a temperature sensor.
In the temperature control method in the fixing device of an image forming apparatus adapted to maintain the standby set point temperature T _s in the standby mode by F, standby mode
The heating lamp at the standby mode set temperature T _s
Turn on for T ₁ and then set standby temperature
The heating lamp is turned off for a time T ₂ until _reaching T _s.
Repeated ON / OFF cycle of heating lamp to F
The ON time T ₁ and OF of the heating lamp which is repeatedly turned on and off in this standby mode within a fixed time T
Either the F time T ₂ or the number of ON / OFF cycles is measured, and the ON time T ₁ and the OFF time T at this measurement are measured.
Calculate the ratio of ₂ and after this measurement,
The same ratio as the OFF time ratio and the ON time T ₁ during measurement
Shorter ON time T ₃ and OFF shorter than OFF time T ₂
Controlling the power consumption of the heating lamp heating lamp at time T ₄ ON, while maintaining the standby set point temperature for a predetermined time t at the energy saving mode turned OFF.

[0006]

Further, in the temperature control method in the fixing device of the image forming apparatus in which the heating lamp is turned on and off by the temperature control by the temperature sensor to maintain the standby set temperature Ts in the standby mode, the temperature control method is repeated in the standby mode. O of the heating lamp
N time and OFF time are fixed time T, or ON, OFF
One cycle is measured as one cycle, the ratio of ON time and OFF time at the time of this measurement is calculated, and after this measurement, the heating in the standby mode at the time of this measurement is performed based on this calculation result. The required power of the lamp is calculated, and control is performed in the energy saving mode for a predetermined time t while maintaining the temperature at the time of measurement by cycle steal or phase control so as to be equal to it.
After that, it returns to the standby mode again for a certain time T,
Alternatively, one of the predetermined number of cycles is measured with ON and OFF as one cycle, and the ON time and O
The ratio of the FF time is calculated, and based on the calculation result, the heating lamp is controlled for the predetermined time t in the energy saving mode while the temperature at the time of the measurement is maintained again.

Then, the ON time T ₁ and the OFF time T ₂ of the heating lamp by the temperature sensor in the standby mode are set.
The time T required to measure is shorter than the time t during which the energy saving mode is performed.

[0009]

[Operation] The heating lamp of the fixing device in the standby mode after the warm-up or the copying operation is finished is first turned on and off by the temperature sensor for a certain period of time to be controlled to the standby set temperature. Next, temperature control is performed in an energy saving mode that consumes less power than ON / OFF control during control by the temperature sensor.

[0010]

EXAMPLES Examples of the present invention will be described with reference to the drawings. FIG. 1 schematically shows an example of an electrophotographic printer to which the present invention is applied. In this printer, a document image is input to a photoconductor 2 by an image input device 1.
The latent image formed by being input to the photoconductor 2 is the developing device 3
After being developed into a toner image by the transfer device 4, it is transferred by the transfer device 4 onto the paper 6 fed by the paper feeding device 5, and then by the fixing device 7.
It is fixed at and is discharged.

The upper fixing device 7 is composed of a pressure roll 8 and a heating roll 9, one of which is fixed and the other is movable in the contact and separation directions and is spring-biased in the contact direction. . A heating lamp 10 is provided in the heating roll 9, and the heating roll 9 is heated by the heating lamp 10. The temperature of the heating roll 9 by the heating lamp 10 is controlled to an optimum temperature during warm-up of the printer, standby, and copy operation. The temperature control is performed by turning on and off the heating lamp 10.

The present invention relates to the temperature control of the heating roll 9 at the time of standby, and the first embodiment of the temperature control method for this is shown below. FIG. 2 is a block diagram showing a configuration for controlling the temperature of the heating roll 9 by the heating lamp 10. The heating lamp 10 is the heating lamp 10.
SSR (Solid State) to turn ON / OFF
It is connected to the power supply 12 via the Relay 11.
13 is a temperature sensor for measuring the surface temperature of the heating roll 9,
Reference numeral 14 is a control device.

The control method of the heating roll 9 in this embodiment will be described with reference to the flow chart shown in FIG. When the warm-up is completed and the copying operation is in standby (standby) (step 1), the fixing device 7 is in the normal standby mode, and the heating roll 9 is controlled by the temperature sensor 13 to control the temperature as shown in FIG. It is controlled to the standby set point temperature T _s as shown. Heating lamp 1 at this time
The temperature control of 0 is standby as shown in A part of FIG.
The set temperature T ₃ is controlled as a lower limit value. That is,
When the temperature of the heat roll 9 becomes the standby setting temperature T _s pressure
The heat lamp 10 is turned on for T ₁ hour,
After that, the temperature of the heating roll 9 is set to the standby set temperature T _s.
Is turned off for a time T ₂ until
_It is repeatedly turned on for ₁ hour and turned off for ₂ hours.

Therefore, the ON time T _{1 at} this time and the OFF time
Measure each of the times T ₂ (step 2), then
The average value of the ON time T _{1 at} a constant measurement time T and O
The ratio _T 1 / _{T 2} of the average value of FF time _{T 2} to compute at calculating means (step 3). The energy saving mode B is controlled on the basis of the above calculation result in the normal standby mode A over the fixed time T. At the time of the above measurement at this time
In the interval T, as shown in FIG. 6, the heating lamp 10 is turned on and off.
The time is an integral multiple of the FF cycle.

That is, the normal standby mode A described above.
ON time T ₁ which is controlled by the temperature sensor 9 when the
Ri short ON time _{T 3} and the OFF time _{T 2} shorter than the OFF time _{T 4,} calculates the ratio _T 3 / _{T 4} such that the relationship between the _T 1 / _{T 2} and the same rate (Step 4). Then, in the energy saving mode B, the ON time T ₃ and the OFF time T _{4 are 0} .
The N and OFF control is performed (step 5) to control the heating lamp 10 for a predetermined time t to maintain the standby set temperature T _S. At this time, since T ₁ > T ₃ , the temperature waveform due to ON and OFF in the energy saving mode B becomes lower than the temperature waveform due to ON and OFF in the normal standby mode A, and the total input power is reduced to save energy. Becomes

The energy saving mode B is performed for a longer time (T <t) than the normal standby mode A. During this time, it is confirmed that the start button for copying is not pressed (step 6), and then the predetermined time is reached. Energy saving mode B continues for t (step 7). After the elapse of the predetermined time t, the normal standby mode A is returned to again, the temperature control by the temperature sensor 13 is performed, and
The standby set temperature T _S is maintained by repeating the N time T ₁ and the OFF time T _2, and the average value of the ON time T ₁ and the OFF time T _{2 at} the constant time T is calculated again, and the above step 2 is performed. Do ~ 7. As a result, the ON / OFF time (T ₃ , T ₄ ) in the energy saving state is corrected even when the ambient temperature of the fixing device 7 and the input voltage change. The calculation and control in each step of the above operation are performed by the controller 14.

In order to perform the above operation in the first embodiment, the fixing device shown in FIG. 2 has (1) ON / OFF control means by the temperature sensor 13, and (2) a constant time T. Alternatively, with ON and OFF as one cycle, the ON time T ₁ and OFF of the heating lamp 10 for a predetermined number of cycles
Measuring means for measuring the time _{T 2,} a calculating means for calculating (3), the ratio _T 1 / _{T 2} of the ON time _{T 1} and OFF time _{T 2} on the basis of the measurement results of (2), (4) the Based on the calculation result, the O
And N and OFF control means. (5) After the elapse of a predetermined time, the temperature is controlled by the temperature sensor 13, and the heating lamp 10 is operated for a predetermined number of times with the constant time T or ON or OFF again as one cycle.
A calculation means for calculating the ratio T ₁ / T ₂ of the ON time T ₁ and the OFF time T ₂ of the above is activated.

Further, a second embodiment to be described later is provided with (1) and (2) in the first embodiment, and is heated based on the measurement results of (6) and (2). It is provided with means for calculating the required power of the lamp 10 and control means for performing cycle steal or phase control for a predetermined time based on the results of (7) and (6). (8) After the elapse of a predetermined time, the heating lamp 10 is turned off for a predetermined number of times again with a certain time or ON / OFF as one cycle.
A calculating means for calculating the ratio of N hours and OFF times is activated.

FIG. 3 is a block diagram showing a second embodiment, in which a cycle steal (or phase controller) 15 is interposed between the power source 12 and the SSR 11. The control method of the heating roll 9 in this embodiment will be described with reference to the flowchart shown in FIG.

When the warm-up is completed and the copying operation is on standby (step 1), the fixing device 7 is in the normal standby mode, and the heating roll 9 is in the temperature sensor 1.
As shown in FIG. 7, the temperature is controlled to the standby set temperature T _S by the temperature control by No. 3. Temperature control of the heating lamp 10 at this time is as shown by a portion A of FIG. 7, T ₁ hour ON,
OFF for T ₂ is repeated.

Therefore, the ON time T _{1 at} this time and the OFF time
Measure each of the times T ₂ (step 2), then
The ratio T ₁ / T ₂ of the average value of the ON time T _{1 and} the average value of the OFF time T _{2 in} the constant time T is calculated (step 3), and based on the calculation result, the constant time in the normal standby mode is calculated. The required electric power P of the heating lamp 10 inside is calculated from a predetermined calculation table (step 4).

Then, the energy saving mode B is controlled based on the required power. That is, this energy saving mode B
Then, cycle steal (or phase control) is performed so as to be equal to the electric power required to maintain the standby set temperature T _S (step 5 ), and the heating roll 9 is set to the target set temperature T _S or a temperature in the vicinity thereof. It is maintained for a predetermined time t (step 7 ).

At this time, the electric power supplied to the heating lamp 10 becomes the minimum necessary, and energy is saved. This energy saving mode is continuously performed for a predetermined time t longer than the constant time T for measurement, and again, the average value of the ON time T ₁ of the temperature control of the heating roll 9 by the temperature sensor 13
And the required power is reviewed by calculating the ratio of the average value of the OFF time T ₂ and the optimum cycle steal or phase control is performed.

Further, in both of the above-mentioned embodiments, the temperature sensor 13 turns on the O of the heating lamp 10 at the same time when the copying operation is started.
By switching to N / OFF control, it is possible to cope with a sudden temperature change of the heating roll 9 at the start of the copying operation. Further, in both of the above-described embodiments, the ON / OFF measurement during the temperature control by the temperature sensor 13 is performed at O instead of the fixed time T.
The number of N, OFF cycles may be measured.

In the first embodiment, the temperature drift width of the heating roll 9 during standby can be reduced, and more stable fixing property can be guaranteed. Further, it is possible to maintain the temperature of the heating roll 9 with less electric power with respect to the target set temperature, which contributes to energy saving.
Further, since the OFF time of the heating lamp 10 is relatively short and the heating lamp 10 is hard to cool, the inrush current generated at the moment when the heating lamp 10 is turned ON is also small, and the secondary failure due to power supply voltage fluctuation can be prevented.

In addition, in the second embodiment, in addition to the function and effect of the first embodiment, in addition to the target set temperature,
It is possible to maintain the temperature with less power,
Further, since the heating lamp 10 does not have an OFF time, the heating lamp 10 does not cool, and the voltage movement due to the OFF operation does not occur.

In both of the above-mentioned embodiments, the power consumption is set to be smaller than that in the normal standby state for a predetermined time in the standby state. However, the power consumption in the standby state is set to the warm state before the standby state. The power consumption may be reduced within a certain time by changing the power consumption during the up operation and the copy operation, and an embodiment will be described below with reference to FIGS. 8 and 9.

In FIG. 8, first, in the image forming apparatus, for example, power consumption P ₀ per hour (3600 seconds)
Is set arbitrarily. Then, at the time of standby after warm-up or copy operation, from the power consumption measured in advance, the power consumption in the operating state before this standby, for example, the power consumption P ₁ at warm-up
Then, the power consumption P ₂ during the copy operation is calculated, and both the power consumptions P ₁ and P ₂ are subtracted from the set power consumption P ₀ within the above 1 hour, and the heating lamp 10 in the standby state is calculated by the remaining power amount P _3. ON / OFF control.

In FIG. 8, the power amount P ₁ at the time of warm-up, the power amount P ₂ at the time of copying operation, and the power amount P ₃ at the time of standby are calculated by the following equations. _{P 1 = W 1 × t 1} /3600 P 2 = W 2 × (t 1 -t 2) / 3600 P 3 = P 0 (P 1 + P 2) and the power consumption P per second in the standby
₄ is P ₄ = P ₃ / (3600-t ₂ ), and when the power consumption of the heating lamp 10 is PL, 1
The PD during the ON / OFF operation of the heating lamp 10 per second is PD = P ₄ × 3600 / PL.

FIG. 9 shows an apparatus for performing the above control. The temperature of the heating lamp 10 (or the heating roll 9) is detected by the temperature sensor 13, and the controller 14 calculates the temperature based on the detected value. , The AC drive circuit 16 is driven.

According to this embodiment, as described above, in order to keep the amount of electric power within a predetermined time constant, in the standby state (standby mode) after warm-up or completion of copying operation, consumption of the operating state immediately before standby is consumed. The power consumption is calculated to determine the power consumption in the standby state. Then, according to the power consumption in this standby state, the heating lamp 10
ON / OFF operation is determined, the control temperature of the heating lamp 10 is determined, the ON / OFF time of the heating lamp 10 is determined, and the time to transition to the preheating temperature of the heating lamp 10 is determined. , Etc., fine control is performed, and the power consumption can always be kept below a predetermined value. Therefore, a high power saving effect can be obtained. Further, since the predetermined power amount determined in advance can be arbitrarily set, further power saving effect can be obtained.

[0032]

According to the present invention, the stable fixing property of the fixing device in the standby state can be guaranteed, the energy can be saved, and the secondary failure due to the fluctuation of the power supply voltage can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory diagram of a printer which is an example of an apparatus to which the method of the present invention is applied.

FIG. 2 is a block diagram showing a configuration for carrying out the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration for carrying out a second embodiment of the present invention.

FIG. 4 is a flow chart showing the first embodiment of the present invention.

FIG. 5 is a flowchart showing a second embodiment of the present invention.

FIG. 6 is an operation explanatory view of the first embodiment of the present invention.

FIG. 7 is an operation explanatory view of the second embodiment of the present invention.

FIG. 8 is an explanatory diagram of a third embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration for carrying out a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image input device, 2 ... Photosensitive member, 3 ... Developing device, 4 ... Transfer device, 5 ... Paper feeding device, 6 ... Paper, 7 ... Fixing device, 8 ... Pressure roll, 9 ... Heating roll, 10 ... Heating Lamp, 11 ... S
SR, 12 ... Power supply, 13 ... Temperature sensor, 14 ... Control device, 15 ... Cycle steel or phase control device, 1
6 ... AC drive circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsumi Kurita 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business Office (72) Hideo Saito 2274, Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business In-house (72) Hideshi Shimazaki 2274 Hongo, Ebina-shi, Kanagawa Fuji Zerox Co., Ltd. Ebina Works (56) Reference JP-A-6-324532 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (3)

(57) [Claims] 1. A temperature control method for a fixing device of an image forming apparatus, wherein a heating lamp is turned on and off by a temperature control by a temperature sensor to maintain a standby set temperature T _s in the standby mode. , in the standby mode setting temperature _{T s}
Turn on the heating lamp for time T ₁ , then start
It is applied over the time T ₂ until the temperature reaches the set temperature T _s.
Turn the heat lamp off Turn the heat lamp on and off
Repeats the cycle, ON in this standby mode, ON time within a predetermined time T of the heating lamps OFF is repeated _{T 1} and an OFF time _{T 2} or ON,, measured either in the number of cycles OFF, the measurement Ratio of ON time T ₁ and OFF time T ₂
The rate is calculated, and after this measurement, the time ratio of ON and OFF at the time of the above measurement
ON time T at the same rate and shorter than ON time T ₁ at the time of measurement
₃ and the power consumption of the heating lamp is controlled in a state where the standby set temperature is maintained for a predetermined time t in the energy saving mode in which the heating lamp is turned on and off in the OFF time T ₄ shorter than the OFF time T _2. A characteristic temperature control method in a fixing device. 2. A temperature control method in a fixing device of an image forming apparatus, wherein a heating lamp is turned on and off by a temperature control by a temperature sensor to maintain a standby set temperature T _s in the standby mode. The ON time and OFF time of the repeated heating lamp are set to a fixed time T, or one of a predetermined number of cycles is set to ON and OFF as one cycle, and the ratio of the ON time and the OFF time at this measurement is calculated. After this measurement, calculate the required power of the heating lamp in the standby mode at the time of this measurement based on this calculation result, and maintain the temperature at the time of the above measurement by cycle steal or phase control so as to be equal to it Control is performed in energy saving mode for t and then the above Returning to by mode, a predetermined time T or ON, to measure one of a predetermined number of cycles OFF as one cycle, ON time and OF during the measurement,
The ratio of the F time is calculated, and based on the calculation result, the temperature of the fixing device is controlled by controlling the heating lamp for the predetermined time t in the energy saving mode while maintaining the temperature at the time of measurement again. Control method. 3. The time T required for measuring the ON time T ₁ and the OFF time T ₂ of the heating lamp by the temperature sensor in the standby mode is shorter than the time t during which the energy saving mode is performed. 2. A temperature control method in the fixing device according to 2 .