JPH10143003A - Thermal fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and correctly discriminate a heat generating unit corresponding to temp. detecting means by discriminating the heat generating means corresponding to respective temp. detecting means. SOLUTION: In this device, a controlling means 10, provided with a CPU 9 in which detected output by first temp. detecting means 7 is input, and converts the output inputted to the temp. value with the CPU 9, makes a center part 2a of a fixing roller 2 a specified temp. and making a center heat generating unit 2a generating heat by controlling conduction of the first triac 5, base on this temp. value, at the time of the normal operation. Similarly, the CPU 9 in which the output of second temp. detecting means 8 is input, makes either end part 2b on the fixing roller 2 becoming to the specified temp. by converting the output into the temp. value corresponding to the size of a paper sheet allowed to pass, at the time of the normal copying operation, by making the respective end part heat generating unit 4 allowed to control the conduction of the second tiac 6, based on this temp. value. In such a manner, the respective heat generating unit 2a and 2b can be correctly decided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat fixing device for a copying machine or the like.

[0002]

2. Description of the Related Art A conventional heat fixing device of this type is disclosed in
There is one disclosed in JP-A-2-254481 and known. As shown in FIGS. 6 and 7, the heat generating portion of the fixing roller 2 of the heat fixing device 1 'is divided into a plurality of portions, and each of the heat generating portions 3, 4, and 4' is individually turned on and off. Possible control means 10 'and respective heating elements 3, 4,
4 ', a plurality of temperature detecting means 20, 21, 22 for controlling the output of these temperature detecting means 20, 21, 22 and the use state (paper size, standby, continuous use) information. Ten'
To control the temperature of the heat fixing unit to be constant.

Further, in the above-described device, the triacs (not shown) for turning on and off the energization of the heaters 3, 4 and 4 'which are divided into a plurality of parts are different from each other. , 4 'are selected and those triacs are provided with protection circuits, respectively, so that there is an erroneous connection between the triac and the heaters 3, 4, 4'. For example, when the capacity of the triac that controls the heater 3 is inappropriate for the capacity of the heater 3, particularly when the capacity of the triac is smaller than the capacity of the heater 3, , The protection circuit is activated and does not turn on, so that erroneous wiring can be found.

[0004]

However, in the conventional heat fixing device as described above, if each of the temperature detecting means is erroneously wired so as to detect the temperature of the heat generator on the opposite side, each of the heat fixing devices has a problem. There is a problem that the lighting control of the heat generator becomes abnormal and proper temperature control cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat fixing device which can solve the problems of the conventional heat fixing device and can easily and surely determine a heat generator corresponding to each temperature detecting means. To be.

[0006]

According to the present invention, in order to achieve the above object, according to the first aspect of the present invention, the heating device of the fixing roller is provided with a heating device adapted to the size of the paper used. Determining means for determining a heating element corresponding to each temperature detecting means in a thermal fixing device having a control means having a temperature detecting means configured to control lighting of each heating element independently of each other Is provided.

The invention according to a second aspect is characterized in that the control means turns on only one heater until the determination of the heater is completed.

According to a third aspect of the present invention, the discriminating means is configured to determine, based on a temperature value detected by each temperature detecting means after a predetermined time has elapsed after one of the heat generating elements is turned on. It is characterized in that a heater corresponding to each temperature detecting means is determined.

According to a fourth aspect of the present invention, only one of the heaters is turned on, and the discriminating means detects the temperature detected by the respective temperature detecting means after the first predetermined time has elapsed. After the first temperature value and the first temperature value are detected, the second
After a lapse of a predetermined time, a heat generator corresponding to each temperature detecting means is determined based on the second temperature value detected by each temperature detecting means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention shown in the drawings, the same parts as those of the prior art are referred to by the same reference numerals, and description thereof will be omitted. In the first embodiment of the present invention shown in FIG.
A central heating device 3 having a heater for heating a central portion 2a of the fixing roller 2 and an end heating device 4 having a heater for heating an end portion of the fixing roller 2 are provided in a fixing roller 2 of the heat fixing device 1.
On the surface of the fixing roller, there are provided first temperature detecting means 7 comprising a thermistor for detecting the temperature of the central surface of the fixing roller, and second temperature detecting means comprising a thermistor for detecting the temperature of the end surface of the fixing roller. Means 8 are provided.

The control means 10 having a CPU 9 (arithmetic means) to which the output detected by the first temperature detecting means 7 is input, converts the input output to a temperature value by the CPU 9 to perform normal copying. During operation, based on this temperature value,
The energization of the first triac 5 is controlled to cause the central heater 3 to generate heat so that the central portion 2a of the fixing roller 2 is set to a predetermined temperature.
Similarly, the CPU to which the output of the second temperature detecting means 8 is input
9 converts the output to a temperature value, and controls the energization of the second triac 6 based on the temperature value according to the size of the sheet to be passed during a normal copying operation, thereby controlling the end portion heat generation. The heater 4 is heated to bring the end 2b of the fixing roller 2 to a predetermined temperature.

A cover (not shown) of a copying machine or the like includes
An opening / closing detecting means comprising a SW for detecting the opening / closing of the cover is provided, and the control means 10 to which the ON / OFF signal detected by the opening / closing detecting means is inputted cuts off the power supply to the relay 12 when the cover is opened. The contact of the relay 12 is opened to stop the supply of power to the central heater 3 and the end heater 4, and when the cover is closed, power is supplied to the relay 12 so that the relay 12 is energized.
Twelve contacts are closed to supply power to the central heater 3 and the end heater 4.

The discriminating means 11 comprises a CPU 9 and a control means 10 having storage means 13 for receiving the respective outputs of the first and second temperature detecting means and storing the temperature value converted by the CPU 9. It is.

In such a device, when a power supply of a copying machine or the like or a cover SW is turned on, first, the first and second power supplies are turned on.
The temperature detectors 7 and 8 detect and output temperatures, respectively, and the CPU 9 outputs the first temperature value (a) of the first temperature detector 7 and the first temperature value (b) of the second temperature detector 8. Is calculated and stored in the storage means 13, and then, until the control means 10 completes the determination of the heat generator, one of the heat generators, in this case, Only the central heater 3 is turned on, and after a predetermined time elapses,
The temperature detecting means 7 and 8 respectively detect and output the temperature, and the CPU 9 outputs the second temperature value (a ') of the first temperature detecting means 7 and the second temperature value (b) of the second temperature detecting means 8. ′)
Is calculated and stored in the storage means 13, and the first temperature values (a) and (b) and the second temperature values (a ') and (b') are calculated.
Respectively, the first temperature difference value A (A = a'-a)
And a second temperature difference value B (B = b'-b),
And B to determine their magnitude relationship (in this case,
A> B), and based on the reference condition of the magnitude relation of the temperature difference value which indicates the case where the temperature difference value is normally connected to the CPU 9 and if the reference condition is satisfied, the respective heaters 3 4 is assumed to correspond to the first and second temperature detecting means 7 and 8, respectively, and it is determined that the respective heaters 3 and 4 and the first and second temperature detecting means 7 and 8 are normally connected. Based on the judgment, the control means 10 starts the temperature control of the center and end heaters 3 and 4 for enabling the copying. In this case, by turning on only one of the heaters, it becomes easy to make a difference between the temperature readings of the respective temperature detecting means.

When the first temperature detecting means 7 detects an erroneous connection (erroneous wiring), for example, the temperature of the end portion 2b of the fixing roller 2 heated by the heat generator 4, the erroneous connection is performed by the CPU 9. It is determined that the heater 4 does not correspond to the second temperature detecting means 8 based on the reference condition of the magnitude relation of the temperature difference value. Then, based on this determination by the CPU 9, the control means 10 may display an erroneous connection on the display device so that the operator can visually recognize it.

FIG. 2 is a flow chart showing the processing operation when the power is turned on. In FIG. 2, the power supply O indicating that the initialization and the power are turned on (steps 2-1 and 2-2).
The N flag is turned on (step 2-3). This flowchart is executed only once when the power is turned on.

Referring to FIG. 3, which is a flowchart showing the start of the heating device discriminating process, the power ON flag is checked to determine whether the power is turned on (step 3-2), and if it is ON (step 3-2Y). Turn off the flag and set 2
The central heater 3 of the heaters is turned on (step 3-
5) Next, a heater determination flag indicating that the heater is being determined is turned on (step 3-6), and at this lighting time, the first temperature values (a) and (b) are determined. The second temperature reading timer for setting a predetermined time after the central heater 3 is turned on is started (step 3-9).

Then, the heating device discriminating process is performed as shown in the flowchart of FIG.
(B ') is stored in the storage means 13 (step 4-7,
4-8) A first and second temperature difference value A is determined from the first temperature values (a) and (b) and the second temperature values (a ') and (b') in order to determine a heater. , B (step 4
-9, 4-10), A is compared with B, and if A> B (step 4-11Y), the CPU 9 sets the temperature difference based on the reference condition of the magnitude relation of the temperature difference values set in the CPU 9 in advance. hand,
The central heater 3 is recognized as a heater for controlling the temperature of the central portion of the fixing roller, and the first temperature detector 7 and the central heater 3 correspond to each other. It is determined that they are correctly connected as corresponding ones (steps 4-12, 4-13). Conversely, if A <B (step 4-11N), the CPU 9 sets the first temperature detecting means 7 on the basis of
It recognizes that the end heater 4 corresponds, or that the second temperature detecting means 8 and the center heater 3 correspond, and in any case, it is determined that the connection is incorrect (step 4). -1
(5, 4-16), if necessary, an erroneous connection is displayed on a display means (not shown) and visually recognized by an operator. In this flowchart, the power is turned on.
Since the flag is executed only when the flag is ON, this flow is executed only once after the power is turned on, as in the flow of FIG.

As shown in the flowchart of the temperature control processing operation, as shown in FIG. 5, if both the power ON flag and the heating element determination flag are ON (steps 5-2Y and 5-4Y), the temperature control processing is started. Not performed. That is,
Until the determination of the heating device is not determined, the temperature control of the heating device is not performed, and when the heating device and the corresponding temperature detecting means are normally connected (steps 5-2N and 5-5-2).
4N), the temperature control of the heat generator is started (step 5-6).

The second embodiment is different from the first embodiment in that
The control means 10 sets in the control means 10 one of the respective heaters, for example, a first predetermined time after the central heater 3 is turned on, and a second predetermined time after the first predetermined time has elapsed. Things.

In such a device, first, after the first predetermined time has elapsed, the first and second temperature detecting means 7 and 8 respectively detect and output the temperature, and the CPU 9 causes the first-degree detecting means 7 to detect the temperature.
The first temperature value (a ₁ ) of the second temperature detection means 8 and the first temperature value (b ₁ ) of the second temperature detection means 8 are calculated and stored in the storage means 13, and then the determination of the heat generator is completed. In the meantime, after the first predetermined time has elapsed and after the second predetermined time has elapsed, the first and second temperature detecting means 7 and 8 similarly detect and output the temperatures, respectively, and the CPU 9 executes the first-degree detecting means. first temperature value of 7 ', a first temperature value (b ₁ of the second temperature detecting means 8 (a _1)') and in operation and stored in the storage means 13, the first temperature value (a ₁ ), (B ₁ ) and the second temperature values (a ₁ ′), (b ₁ ′), the first temperature difference value A
₁ (A ₁ = a ₁ '-a ₁ ) and the first temperature difference value B ₁ (B ₁ =
b ₁ ′ −b ₁ ), and A ₁ and B ₁ are compared to judge the magnitude relationship (A ₁ > B _{1 in} this case). The heaters 3 and 4 correspond to the first and second temperature detecting means 7 and 8, respectively, if the reference conditions are satisfied, based on the reference condition of the magnitude relation of the temperature difference value indicating the case where they are connected to each other. As a result, it is determined that each of the heat generators 3 and 4 and the first and second temperature detecting means 7 and 8 are normally connected, and based on this determination, the control means 10 sets the copy-enabled state. And the temperature control of the center and end heaters 3 and 4 to start.

In this case, the first temperature difference value A ₁ and the second temperature difference A ₁ , regardless of the temperature of each heater near the respective heaters before the heater determination process. The difference between the difference values B ₁ can be clearly detected, and the central heater 3 corresponding to the first temperature detecting means 7 and the end heater 4 corresponding to the second temperature detecting means 8 are correctly connected. Can be reliably determined.

[0023]

The present invention is as described above. According to the first aspect of the present invention, in the above-described heat fixing device, the determining means for determining the heat generator corresponding to each temperature detecting means is provided. Since the heaters are provided, it is possible to reliably determine the heaters, prevent erroneous connection of the heaters corresponding to the respective temperature detecting means, and prevent abnormal lighting control of the fixing device. There is an effect that can be.

According to the second aspect of the present invention, the control means turns on only one of the heaters until the determination of the heaters is completed, so that the difference in temperature rise near each heater is large. Therefore, there is an effect that the heater can be easily determined.

According to a third aspect of the present invention, the discriminating means, based on a temperature value detected by each temperature detecting means after a predetermined time has elapsed after one of the heat generating elements is turned on. Since the heaters corresponding to the respective temperature detecting means are determined, it is possible to determine the heaters in a state where the temperature difference is largely open, so that there is an effect that more reliable determination can be performed.

According to a fourth aspect of the present invention, only one of the heaters is turned on, and the discriminating means detects the temperature detected by the respective temperature detecting means after the first predetermined time has elapsed. After the first temperature value and the first temperature value are detected, the second
After the lapse of a predetermined time, the heaters corresponding to the respective temperature detecting means are determined based on the second temperature value detected by the respective temperature detecting means. In addition, the difference between the two temperatures can be significantly detected, and the discrimination process can be performed reliably.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is a flowchart of an initial processing operation when the power is turned on.

FIG. 3 is an operation flow chart when starting a process of determining a heating device according to the first embodiment;

FIG. 4 is an operation flowchart of a heating device discriminating process according to the first embodiment;

FIG. 5 is an operation flowchart of a temperature control process of the above.

FIG. 6 is a schematic configuration diagram of a conventional heat fixing device.

FIG. 7 is a schematic circuit diagram of the above circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal fixing device 2 Fixing roller 3 Central heating device 4 End heating device 5 Triac 6 Triac 7 First temperature detecting means 8 Second temperature detecting means 9 CPU 10 Control means 11 Determination means

Claims (4)

[Claims] 1. A heating device for a fixing roller, wherein the heating device is divided into two in accordance with the size of a sheet to be used, and a control device having a temperature detection device for controlling lighting of each heating device independently. A heat fixing device comprising: a heat fixing device provided with a discriminating means for discriminating a heat generator corresponding to each temperature detecting means. 2. The heat fixing device according to claim 1, wherein the control unit turns on only one heat generator until the determination of the heat generator is completed. 3. A discriminating means corresponding to each temperature detecting means based on a temperature value detected by each temperature detecting means after a lapse of a predetermined time after one of the heaters is turned on. The heat fixing device according to claim 1, wherein a heat generator that performs heating is determined. 4. The method according to claim 1, wherein only one of the heat generators is turned on, and the determining means determines whether or not the first predetermined time has elapsed.
A first temperature value detected by each temperature detecting means;
After the temperature value is detected, after a lapse of a second predetermined time, based on the second temperature value detected by each temperature detecting means, a heater corresponding to each temperature detecting means is determined. The heat fixing device according to claim 1.