JPH1010916A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of adequately preventing malfunction caused by overheating of a device. SOLUTION: A fixing part detects the surface temperature of a fixing roller with a thermistor, supplies/stops electric power to a fixing heater, and controls the fixing roller to the specified temperature. Continuous recording is performed with an electrophotography type recording device, continuous fixing operation is performed with the fixing part, and when temperature within a device is raised, malfunction such as fixing of a toner which is developing powder is generated. In the electrophotography type recording device, the temperature within the device is checked S1 with a temperature sensor whether it is equal to or higher than the specified temperature, and if it does not reach the specified temperature, copying operation is continued S2. When copy is continued and the temperature within the device exceeds the specified temperature, the supply of the electric power to the fixing heater is stopped and copying operation is discontinued S4. After that when the temperature within the device is lowered than the specified temperature, the supply of electric power to the fixing heater is resumed and copying operation is resumed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device,
More specifically, the present invention relates to a fixing device which is applied to a recording device of an electrophotographic system or the like and fixes toner adhered to the recording paper to the recording paper by a fixing heater.

[0002]

2. Description of the Related Art Recently, since the printing quality is good,
As image forming apparatuses such as copying machines and facsimile apparatuses, so-called electrophotographic recording apparatuses have been used.

In such an electrophotographic recording apparatus, an electrostatic latent image is formed on a photoreceptor by light modulated based on information, and toner is attached to the photoreceptor on which the electrostatic latent image is formed. develop. The toner adhered to the photoreceptor is transferred to a recording paper, the recording paper having the toner adhered is conveyed to a fixing unit, and the toner is fixed on the recording paper by a fixing roller of the fixing unit.

A conventional fixing device generally supplies AC power to a fixing heater of a fixing roller via a power supply unit.
The fixing roller is heated by the fixing heater. The temperature of the fixing roller is detected by a thermistor, and based on the detection result of the thermistor, a control circuit controls on / off of a power supply unit to control the fixing heater to a predetermined fixing temperature.

In addition, the fixing device protects the fixing heater from overheating by a temperature fuse or a thermostat, or protects the fixing heater from overheating by an analog comparator, in case an abnormality such as a runaway of a control circuit occurs.

[0006]

However, in such a conventional fixing device, the energization of the fixing heater is simply turned on / off based on the detection result of a temperature sensor such as a thermistor. Since the temperature of the fixing heater is controlled to be constant, the temperature inside the fixing device, and eventually, the recording device rises, and there is a problem that abnormal overheating occurs and causes malfunction or failure.

That is, recently, there has been a demand for space saving in an image forming apparatus using an electrophotographic recording apparatus.
The image forming apparatus is often attached to a wall or installed in a narrow installation space with other equipment or a desk. Under such installation conditions, even if a heat exhaust fan is provided, the exhaust efficiency is reduced, and the inside of the fixing device is overheated. In particular, if the continuous recording operation is performed for a long time, the temperature inside the fixing device is overheated. You.

When the temperature inside the fixing device exceeds a predetermined temperature, toner as a developer is fixed, the driving load increases, the driving source (motor, etc.) is locked, and the transmission components are locked. There is a problem that malfunctions and failures occur.

Therefore, according to the first aspect of the present invention, the temperature inside the case in which the fixing device is housed is detected, and when the temperature inside the case exceeds a predetermined temperature, the fixing operation is temporarily stopped, so that the inside of the fixing device is stopped. It is an object of the present invention to provide a fixing device capable of performing an appropriate operation by preventing overheating of the fixing device.

According to a second aspect of the present invention, the internal temperature of the case in which the fixing device is housed is detected, and when the internal temperature of the case exceeds a predetermined temperature, the recording paper transport interval to the fixing device is extended by a predetermined interval. Accordingly, an object of the present invention is to provide a fixing device capable of performing an appropriate operation by preventing overheating of the temperature in the fixing device.

According to a third aspect of the present invention, the number of recording papers to be continuously fixed is detected, and when the number of continuous recording papers exceeds a predetermined number, the conveying interval of the recording paper to the fixing device is extended by a predetermined interval. This prevents overheating of the temperature inside the fixing device,
It is an object of the present invention to provide a fixing device capable of performing an appropriate operation.

[0012]

According to a first aspect of the present invention, there is provided a fixing device, wherein the recording paper is accommodated in a predetermined case and the toner transferred to the recording paper is transferred to the recording paper by a fixing roller heated by the heat of a fixing heater. A fixing device for detecting the temperature in the case, and a control unit for temporarily stopping the fixing operation when a temperature detected by the temperature detecting unit exceeds a predetermined temperature. The above objective has been achieved.

According to the above arrangement, the temperature inside the case in which the fixing device is housed is detected, and when the temperature inside the case exceeds a predetermined temperature, the fixing operation is temporarily stopped. It can be prevented, and an appropriate operation can be performed.

According to a second aspect of the present invention, in the fixing device, the toner transferred to the recording paper which is accommodated in a predetermined case and conveyed at predetermined time intervals is fixed by a fixing roller heated by the heat of a fixing heater. In a fixing device for fixing the recording paper, a temperature detecting means for detecting a temperature in the case, and a control means for lengthening a recording paper conveyance interval by a predetermined interval when a temperature detected by the temperature detecting means exceeds a predetermined temperature. , The above object is achieved.

According to the above construction, the temperature in the case in which the fixing device is housed is detected, and when the temperature in the case exceeds the predetermined temperature, the interval for transporting the recording paper to the fixing device is lengthened by a predetermined interval. Overheating of the temperature inside the fixing device can be prevented, and appropriate operation can be performed.

According to a third aspect of the present invention, in the fixing device, the toner transferred to the recording paper housed in a predetermined case and conveyed at predetermined time intervals is fixed by a fixing roller heated by the heat of a fixing heater. In a fixing device for fixing the recording paper, a counting means for counting the number of the recording paper continuously conveyed, and when the counted number of the counting means exceeds a predetermined number, the conveyance interval of the recording paper is set to a predetermined interval. The above object is achieved by providing a control means for increasing the length.

According to the above construction, the number of recording sheets to be continuously fixed is detected, and when the number of continuous recording sheets exceeds a predetermined number, the conveyance interval of the recording sheets to the fixing device is increased by a predetermined interval. It can prevent overheating of the temperature inside the device,
Appropriate operation can be performed.

[0018]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

1 to 3 show an embodiment of the fixing device of the present invention. FIG. 1 shows an electrophotographic recording apparatus 1 to which an embodiment of the fixing device of the present invention is applied. Fixing unit 2
FIG.

In FIG. 1, an electrophotographic recording apparatus 1 comprises:
A fixing unit (fixing device) 2 is provided. The fixing unit 2 includes a fixing roller 3 and a pressure roller 4.
Is pressed against the fixing roller 3 by a pressure member (not shown). The fixing roller 3 and the pressure roller 4 are covered with covers 5 and 6, respectively, and the toner is transferred to a contact portion between the fixing roller 3 and the pressure roller 4 by a transfer unit (not shown) of the electrophotographic recording apparatus 1. The recording paper is conveyed.

A fixing heater 7 is housed in the fixing roller 3, and a fixing roller 3 is provided on the surface of the fixing roller 3.
A thermistor 8 for detecting the surface temperature of the device is mounted. A thermostat 9 for protecting the fixing roller 3 from overheating by the fixing heater 7 is attached to the cover 5, and the fixed recording paper is separated from the fixing roller 3 on the surface of the fixing roller 3. The separation claw 10 and the cleaning pad 11 for cleaning the surface of the fixing roller 3 are in contact with each other. The fixing unit 2 is provided with a paper discharge roller 12 for discharging the recording paper on which fixing has been completed to the outside.

The electrophotographic recording apparatus 1 including the fixing unit 2 is covered with a cover (case) 13 in which the inside of the cover 13, that is, the fixing unit 2, A temperature sensor (temperature detecting means) 14 for detecting the temperature in the photographic recording device 1 (temperature in the device) is provided.

The fixing unit 2 heats the fixing roller 3 by a fixing heater 7 and causes the recording paper conveyed between the fixing roller 3 and the pressing roller 4 at predetermined time intervals to be fixed by the fixing roller 3 by the pressing roller 4. The toner on the recording paper is fixed on the recording paper by the heat of the fixing roller 3 while being pressed against the recording paper. The fixed recording paper is conveyed to a paper discharge roller 12, and the paper discharge roller 12 discharges the recording paper to a recording paper tray (not shown).

The fixing section 2 has a circuit block configuration shown in FIG. 2, and has a CPU (Central Processing Unit).
nit) 21, a power supply section 22, a recording sheet counter 23, and the thermostat 9, the fixing heater 7,
A thermistor 8 and a temperature sensor 14 are provided.

The power supply section 22 supplies power to the fixing heater 7 via the thermostat 9 under the control of the CPU 21.
The fixing roller 3 is heated by the fixing heater 7. The thermistor 8 detects the surface temperature of the fixing roller 3, and the thermistor 8 outputs the detected temperature to the CPU 21.

The temperature sensor 14 detects the temperature (temperature in the apparatus) of the electrophotographic recording apparatus 1, ie, the fixing unit 2, and outputs the detected temperature to the CPU 21. 23 is an electrophotographic recording device 1
, The number of recording sheets continuously fixed by the fixing unit 2 (continuous fixing number), and counts the counted number of continuous recording sheets (continuous fixing number). Is output to the CPU 21.

The CPU (control means) 21 includes a thermistor 8
The power supply unit 22 is turned on / off based on the temperature detected from the printer to control the supply / stop of the power to the fixing heater 7, the temperature in the apparatus from the temperature sensor 14, and the continuous recording number from the recording number counter 23. Based on the recording operation,
That is, it temporarily stops the fixing operation and controls the recording paper conveyance interval.

Next, the operation of this embodiment will be described. The electrophotographic recording apparatus 1, that is, the fixing unit 2 includes a CPU 2
1 controls the voltage of the power supply unit 22 and controls on / off, supplies heater power of a predetermined voltage to the fixing heater 7 via the thermostat 9, and the fixing heater 7 generates heat to heat the fixing roller 3. The surface temperature of the fixing roller 3 is detected by the thermistor 8 and output to the CPU 21 so that the CP
U21 turns on / off the power supply unit 22 based on the detected temperature.
By turning off the power, the heater power is supplied / stopped to the fixing heater 7 to control the fixing roller 3 to a predetermined fixing temperature.

However, when continuous recording is performed by the electrophotographic recording apparatus 1 and continuous fixing is performed by the fixing unit 2, the temperature in the electrophotographic recording apparatus 1, that is, the temperature in the cover 13 rises, and the The toner, which is an agent, sticks and the drive load increases, and the drive source (motor, etc.) locks,
Malfunction or failure of transmission parts occurs.

Therefore, the electrophotographic recording apparatus 1 controls the continuation and the suspension of the copying operation based on the temperature in the apparatus.

That is, as shown in FIG. 3, the CPU 21 checks whether or not the internal temperature of the apparatus input from the temperature sensor 14 is equal to or higher than a predetermined temperature (step S1). If not, the copying operation is continued (step S2).

When continuous copying or the like is performed by the electrophotographic recording apparatus 1 and the internal temperature of the apparatus becomes equal to or higher than a predetermined temperature in step S 1, the CPU 21 turns off the power supply unit 22 and supplies the heater power to the fixing heater 7. Is stopped (step S3), and the copying operation is temporarily stopped (step S3).
4).

After temporarily stopping the copying operation and the fixing operation, the CPU 21 returns to step S1 to check whether the temperature in the apparatus is equal to or higher than a predetermined temperature (step S1).
If the temperature is equal to or higher than the predetermined temperature, the stop of the heater power supply and the stop of the copy operation are continued (step S3).

If the internal temperature of the apparatus drops while the copying operation and the fixing operation are stopped, and the internal temperature of the apparatus is lower than the predetermined temperature in step S1, the CPU 21
2 is turned on, the supply of heater power to the fixing heater 7 is restarted, and when the temperature of the fixing roller 3 reaches a predetermined fixing temperature, the copying operation is restarted (step S2).

Therefore, the temperature inside the cover 13 in which the fixing section 2 is housed (the temperature inside the apparatus) is detected, and when the temperature inside the apparatus exceeds a predetermined temperature, the fixing operation (copy operation) is temporarily stopped. Overheating of the temperature inside the fixing unit 2 can be prevented, and an appropriate copying operation, that is, a fixing operation can be performed.

Further, the electrophotographic recording apparatus 1 adjusts the conveyance interval of the recording paper based on the temperature inside the apparatus, thereby eliminating the problem caused by the rise in the temperature inside the apparatus.

That is, as shown in FIG. 4, the CPU 21 checks whether or not the internal temperature of the apparatus is equal to or higher than a predetermined temperature (step S11). If the temperature has not reached the predetermined temperature, the copying operation is continued (step S12).

When continuous copying or the like is performed by the electrophotographic recording apparatus 1 and the internal temperature of the apparatus becomes equal to or higher than the predetermined temperature in step S11, the CPU 21 determines the transport interval time of the recording sheet to be copied, and eventually the fixing section 2 Then, the copy interval, that is, the fixing operation is performed by adjusting the transport interval time (that is, the page interval time) of the recording paper to the page interval time which is longer than the normal page interval time by a predetermined time (step S13).

The CPU 21 checks whether the internal temperature of the apparatus is equal to or higher than the predetermined temperature while performing the copy operation while increasing the page interval time by the predetermined time (step S11). The copying operation is performed at the interval time (step S13). If the internal temperature of the apparatus decreases below the predetermined temperature at step S1, the CPU 21 sets the page interval time to the normal page interval time. It returns to perform the copy operation (step S12).

Therefore, the temperature in the cover 13 in which the fixing unit 2 is housed (the temperature in the apparatus) is detected, and when the temperature in the apparatus exceeds a predetermined temperature, the page interval time for performing the fixing operation (copy operation) is reduced. Since the copy operation (fixing operation) is performed for a predetermined time longer than the normal page interval time, it is possible to prevent the temperature inside the fixing unit 2 from being overheated, and to perform an appropriate copy operation, that is, the fixing operation. Can be.

Further, the electrophotographic recording apparatus 1 adjusts the conveyance interval of the recording paper based on the number of continuous copies (the number of continuous fixings) to eliminate the problem caused by the rise in the temperature inside the apparatus.

That is, as shown in FIG. 5, the CPU 21 checks whether or not the continuous recording number (continuous fixing number) from the recording number counter 23 is equal to or greater than a predetermined number (step S21). If not, the copying operation is continued (step S22).

When continuous copying or the like is performed by the electrophotographic recording apparatus 1 and the number of continuous recordings becomes equal to or more than a predetermined number in step S21, the CPU 21 determines the conveyance interval time of the recording sheet to be copied, and eventually the fixing unit 2 Then, the copy interval, that is, the fixing operation is performed by adjusting the interval time (ie, the page interval time) of the recording sheet to be longer than the normal page interval time by a predetermined time (step S23).

Therefore, when the number of continuous recordings is detected and the number of continuous recordings exceeds a predetermined number, the page interval time for performing the fixing operation (copy operation) is set to be longer than the normal page interval time by a predetermined time, and the copy operation ( (Fixing operation), it is possible to prevent overheating of the temperature in the fixing unit 2,
An appropriate copying operation, that is, a fixing operation can be performed.

As described above, the invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above embodiments, and various modifications may be made without departing from the gist of the invention. Needless to say, it can be changed.

For example, in the process of FIG. 5, the page interval time of the recording paper is adjusted based on the number of continuous recordings, but the temporary recording operation (fixing operation) is stopped as shown in FIG. It may be.

In the above embodiment, the control is performed based on either the internal temperature of the apparatus or the number of continuous recordings. However, the above-described temperature control processing is performed based on both the internal temperature of the apparatus and the number of continuous recordings. You may do so.

[0048]

According to the fixing device of the present invention, the temperature inside the case in which the fixing device is stored is detected, and when the temperature inside the case exceeds a predetermined temperature, the fixing operation is temporarily stopped. In addition, overheating of the temperature inside the fixing device can be prevented, and appropriate operation can be performed.

According to the fixing device of the second aspect of the present invention,
If the temperature inside the case where the fixing device is stored is detected and the temperature inside the case exceeds a predetermined temperature, the recording paper transport interval to the fixing device is extended by a predetermined interval, thereby preventing the temperature inside the fixing device from overheating. And an appropriate operation can be performed.

According to the fixing device of the third aspect of the present invention,
The number of recording sheets to be continuously fixed is detected, and when the number of continuous recording sheets exceeds a predetermined number, the conveyance interval of the recording sheets to the fixing device is increased by a predetermined interval, thereby preventing the temperature inside the fixing device from being overheated. And an appropriate operation can be performed.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a main part of a fixing unit of an electrophotographic recording apparatus to which an embodiment of a fixing device according to the present invention is applied.

FIG. 2 is a main circuit block diagram of the electrophotographic recording apparatus of FIG. 1;

FIG. 3 is a flowchart showing a temperature control process for temporarily stopping a copying operation based on an internal temperature of the electrophotographic recording apparatus of FIG. 2;

FIG. 4 is a flowchart showing a temperature control process for temporarily increasing a page interval time based on an internal temperature of the electrophotographic recording apparatus of FIG. 2;

FIG. 5 is a flowchart showing a temperature control process for increasing a page interval time based on the number of continuous copies by the electrophotographic recording apparatus of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic recording device 2 Fixing device 3 Fixing roller 4 Pressure roller 5, 6 Cover 7 Fixing heater 8 Thermistor 9 Thermostat 10 Separation claw 11 Cleaning felt 12 Discharge roller 13 Cover 14 Temperature sensor 21 CPU 22 Power supply unit 23 Number of recordings counter

Claims (3)

[Claims] 1. A fixing device for fixing toner transferred to a recording sheet contained in a predetermined case to the recording sheet by a fixing roller heated by the heat of a fixing heater, wherein a temperature inside the case is detected. A fixing device comprising: a temperature detecting unit; and a control unit that temporarily stops the fixing operation when a temperature detected by the temperature detecting unit exceeds a predetermined temperature. 2. A fixing device for fixing toner transferred to a recording sheet, which is accommodated in a predetermined case and conveyed at a predetermined time interval, to the recording sheet by a fixing roller heated by the heat of a fixing heater. Temperature detecting means for detecting the temperature in the case; and control means for increasing a recording paper conveyance interval by a predetermined interval when a temperature detected by the temperature detecting means exceeds a predetermined temperature. Fixing device. 3. A fixing device for fixing toner transferred to a recording sheet, which is accommodated in a predetermined case and conveyed at a predetermined time interval, to the recording sheet by a fixing roller heated by the heat of a fixing heater. Counting means for counting the number of paper sheets continuously conveyed, and control means for lengthening the recording paper conveyance interval by a predetermined interval when the counted number of the counting means exceeds a predetermined number. A fixing device characterized by the above-mentioned.