JPH09185288A - Fixing device, and controlling methods for fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely recognize an exchange period for a fixing device, etc., while suppressing the increase of the cost as little as possible and to execute exchange work, etc., before image quality is deteriorated by changing the state of a temperature fuse for detecting a new article, without requiring a special fusing circuit. SOLUTION: The temperature fuse for detecting the new article 8 is arranged in the upper part of a heating roller and when a new fixing device 2 is set in an image forming device 16, the fact that the temperature fuse for detecting the new article 8 is not fused is detected by a CPU circuit 3 and the maintenance counter of an EPROM circuit 4 is initialized. After that, when the heater 13 of the heating roller is energized, the temperature fuse 8 is fused by the heat of the heating roller, so that the fact that the use of the fixed device 2 is started is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus using an electrophotographic process, a fixing device control method, and an image forming apparatus control method.

[0002]

2. Description of the Related Art As an image forming apparatus using an electrophotographic process, there is known an "image forming apparatus" described in JP-A-4-131864. In this image forming apparatus, the replacement unit has a fuse, and when it is determined that the first energization of the replacement unit is started, the fuse is energized to melt the fuse, and the counter is initialized to start counting. , The usage time of the replacement unit, the number of times of use, etc. are measured to optimize the replacement status of the replacement unit and the mounting state.

[0003]

By the way, each unit of such an image forming apparatus generally needs to be replaced at an appropriate period or the number of printed sheets in order to maintain the image quality. If it is used excessively, the toner adheres to the surface of the heating roller or the Teflon layer peels off to cause improper fixing or improper conveyance, which seriously affects the image quality. Therefore, the control unit of the image forming apparatus counts the replacement time set for each unit by the maintenance counter, and when the replacement time is reached, displays a replacement request on the display device and the like, and when the unit is replaced, The maintenance counter can be cleared by manual input, or a small fuse is provided in the unit as in the above-mentioned prior art, and when a new fuse is detected, the fuse is blown and the counter is initialized. There is. However, in such a method, the maintenance counter may be cleared without replacement, and a circuit for blowing the fuse is required, and an expensive small-current-capacity fuse is used to accurately blow the fuse. There is a problem that it becomes necessary and causes an increase in cost.

The present invention has been made in view of the above circumstances. In claim 1, the temperature detecting fuse is used as the new article detecting means, so that the new article detecting means is not required to use a special fusing circuit. It is possible to change the state of, so that it is possible to grasp the replacement time of the fixing device etc. while keeping the cost rise low.
An object of the present invention is to provide a fixing device capable of performing replacement work before image quality deteriorates. In addition, in the second aspect, by starting to energize the heater after detecting whether or not the new-arts detection temperature fuse is blown, it is possible to prevent erroneous blow-out of the new-article detection temperature fuse due to energization of the heater. An object of the present invention is to provide a fixing device control method capable of preventing an erroneous determination from occurring when determining whether it is a new product. Also,
According to the present invention, when the fixing device or the like is not replaced even after the predetermined value is exceeded, the image forming operation is stopped to prevent machine damage due to the occurrence of a defect and waste of paper due to defective printing. It is an object of the present invention to provide a control method of an image forming apparatus capable of performing the above. Also,
According to the present invention, by installing the thermal fuse for detecting a new product on the upper part of the heating roller, it is possible to improve the thermal efficiency and surely blow the thermal fuse for detecting a new product when the heater is energized. Thus, it is an object of the present invention to provide a fixing device capable of preventing an erroneous determination from occurring when determining whether the product is new.
Further, according to the present invention, by performing a heat-absorbing heat treatment on the surface of the new-state detection thermal fuse, even if the new-state detection thermal fuse is installed in a place where thermal efficiency is poor, when the heater is energized, the new-state detection thermal fuse is detected. SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device that can surely blow out the toner and can prevent an erroneous determination from occurring when determining whether the product is new. In addition, according to the present invention, an insulating member is inserted between the heating roller and the temperature fuse for detecting a new product before or other than when the image forming apparatus is mounted on the image forming apparatus. An object of the present invention is to provide a fixing device capable of preventing the thermal fuse for detecting a new article from being blown out before or after being mounted. Further, in the present invention, by making the unit cover and the temperature detection fuse holding member for new product detection separable, the temperature detection fuse for new product detection is isolated during the unit check, and the temperature detection fuse for new product detection is erroneously blown. It is an object of the present invention to provide a fixing device capable of preventing the above. Further, according to claim 8, it is possible to prevent the new-state detection temperature fuse from being easily separated from the outside simply by setting the new-state detection temperature-fuse holding member on the unit cover after the unit check. It is an object of the present invention to provide a fixing device whose use can be prohibited.
Further, in claim 9, by connecting the fixing device main body and the new-article detection temperature fuse with a connector, the new-article detection temperature fuse can be easily replaced when the unit is repaired (regenerated). It is an object of the present invention to provide a fixing device that can improve work efficiency.

[0005]

In order to achieve the above object, the present invention provides a heating roller for heating a sheet on which a toner image is formed, and a pressure for pressing the sheet against the heating roller. In a roll-type fixing device that heats the above-mentioned paper while narrow-pressure conveying it with a roller to fix the above-mentioned toner image on the above-mentioned paper, for detection of a new article that is melted down by secondary heat from the heating roller or convection heat It is characterized in that a temperature fuse is provided, and whether or not the fixing device is new is determined based on whether or not the temperature fuse for detecting the new product is blown. According to a second aspect of the present invention, a temperature measuring unit that measures the temperature of the fixing device and a control unit that controls the heater provided on the heating roller based on the temperature information obtained by the temperature measuring unit, and the fixing device. The fixing device is controlled by a control circuit having a maintenance counter that counts the usage amount or the usage time, and a detection unit that detects the state of the new-state detection temperature fuse, and the detection unit determines that the fixing device is new. When detected, in the fixing device control method for initializing the maintenance counter, the state of the new-state detection temperature fuse is detected by the detection unit after the power is turned on or after the cover is closed, and it is determined whether or not it is a new one. After that, the heater of the fixing device is turned on to heat the heating roller. According to a third aspect of the present invention, in a method of controlling an image forming apparatus that controls the fixing device to perform a fixing operation when the fixing device is set, when the fixing device is new, the fixing device is reset, and then the fixing process is performed. When the value of the maintenance counter, which is incremented according to the usage time or the number of times of use of the device, exceeds the first preset value, a replacement request is issued, and even if the replacement counter reaches the second preset value, image formation is performed when replacement is not detected. The feature is that the operation is stopped. Further, in claim 4, claim 1,
In the fixing device described in any one of 2 and 3, the installation position of the new-state detection temperature fuse is immediately above the heating roller or in the vicinity thereof. According to a fifth aspect, in the fixing device according to any one of the first, second, third, and fourth aspects, a heat-absorbing member that easily absorbs secondary heat and convective heat is applied to the surface of the new-article temperature fuse. It is characterized by that. Further, in claim 6,
The fixing device according to any one of claims 1, 2, 3, 4, and 5, wherein a heat insulating member is disposed between the heating roller and the temperature fuse for detecting a new product when an operation check is performed when the fixing device is manufactured. In this case, the fusing is prevented by mistake, and when the fixing device is set in the image forming apparatus, the heat insulating member is removed from between the heating roller and the thermal fuse for detecting a new product to enable fusing. . Further, in claim 7, in the fixing device according to any one of claims 1, 2, 3, 4, 5, and 6, a holding member that holds the unit cover that constitutes the fixing device and the new-article detecting temperature fuse. To prevent accidental fusing of the new-state detection temperature fuse by separating the holding member from the unit cover and opening the holding member during operation check when the fixing device is manufactured. It has a feature. Also,
According to claim 8, in the fixing device according to any one of claims 1, 2, 3, 4, 5, 6, and 7, when the holding member is set on the unit cover, the holding member is locked. The locking portion of the unit cover and the locking portion of the unit cover are engaged inside the unit cover, and the engagement of the locking portions cannot be released from the outside of the unit cover. Further, in claim 9, claims 1, 2,
In the fixing device according to any one of 3, 4, 5, 6, 7, and 8, the fixing fuse is connected to the new-use detection temperature fuse side held by the holding member and the unit cover side, and the fixing is performed. When repairing the device, it is easy to replace the thermal fuse for detecting a new product.

With the above structure, in the first aspect, the heating roller for heating the sheet on which the toner image is formed and the pressure roller for pressing the sheet against the heating roller heats the sheet while conveying the sheet at a narrow pressure. In the roll-type fixing device for fixing the toner image on the paper, a temperature sensor for new product detection that is melted by secondary heat from the heating roller or convection heat is provided. By determining whether the fixing device is new or not, the state of the above-mentioned temperature fuse for new product detection is changed without the need for a special fusing circuit, thereby reducing the cost increase. While pressing, the fixing time of the fixing device and the like can be surely grasped, and the replacement work can be performed before the image quality deteriorates. According to a second aspect of the present invention, a temperature measuring unit that measures the temperature of the fixing device and a control unit that controls the heater provided on the heating roller based on the temperature information obtained by the temperature measuring unit, and the fixing device. The fixing device is controlled by a control circuit having a maintenance counter that counts the usage amount or the usage time, and a detection unit that detects the state of the new-state detection temperature fuse, and the detection unit determines that the fixing device is new. When detected, in the fixing device control method for initializing the maintenance counter, the state of the new-state detection temperature fuse is detected by the detection unit after the power is turned on or after the cover is closed, and it is determined whether or not it is a new one. After that, by energizing the heater of the fixing device and heating the heating roller, the temperature for new product detection caused by the energization of the heater is started. To prevent erroneous fuse blowing, when judgment is made as to whether the new, misjudgment can be prevented.

According to a third aspect of the present invention, in a method of controlling an image forming apparatus which controls the fixing device to perform a fixing operation when the fixing device is set, when the fixing device is new, it is reset. After that, when the value of the maintenance counter, which is incremented according to the usage time or the number of times of use of the fixing device, exceeds the first preset value, a replacement request is issued, and the replacement is not detected even when the second preset value is reached. , By stopping the image forming operation,
When the fixing device or the like is not replaced even if the predetermined value is exceeded, the image forming operation is stopped to prevent machine damage due to the occurrence of trouble and waste of paper due to defective printing. According to a fourth aspect of the present invention, in the fixing device according to any one of the first, second, and third aspects, the installation position of the temperature fuse for detecting the new product is located immediately above the heating roller or in the vicinity of this immediately above. The thermal efficiency is improved, and when the heater is energized, the thermal fuse for detecting a new product is surely blown out, thereby preventing an erroneous judgment from occurring when judging whether or not the product is new.

Further, in claim 5, claims 1, 2, 3,
In the fixing device according to any one of 4 above, by applying a heat absorbing member that easily absorbs secondary radiation heat and convective heat to the surface of the new temperature detecting fuse, the new temperature detecting fuse is installed in a place where thermal efficiency is poor. Even so, when the heater is energized, the thermal fuse for detecting a new product is surely blown out, thereby preventing an erroneous judgment from occurring when judging whether or not it is a new product. In claim 6, claim 1, claim 1,
In the fixing device according to any one of 2, 3, 4, and 5,
At the time of operation check when the fixing device is manufactured, a heat insulating member is arranged between the heating roller and the temperature fuse for detecting a new product to prevent erroneous fusing, and when the fixing device is set in the image forming apparatus, By removing the heat insulating member from between the heating roller and the new product detection temperature fuse so that it can be blown, a new product detection temperature fuse can be used before unit mounting on the image forming apparatus, such as during unit check. To prevent fusing.

Further, in claim 7, claims 1, 2, 3,
4. The fixing device according to any one of 4, 5, and 6, wherein the unit cover that constitutes the fixing device and a holding member that holds the new-state detection temperature fuse are formed as separate members, and the fixing device is manufactured. When checking the operation of, the holding member is separated or opened from the unit cover to prevent accidental fusing of the above-mentioned temperature fuse for new product detection. Prevents the thermal fuse for detection from being blown by mistake. Further, in claim 8, claim 1, 2,
In the fixing device according to any one of 3, 4, 5, 6, and 7, when the holding member is set on the unit cover, the holding member has a locking portion of the holding member and a locking portion of the unit cover. By engaging the inside of the unit cover to make it impossible to release the engagement of each of the locking parts from the outside of the unit cover, the temperature fuse holding member for detecting a new product is set on the unit cover after the unit check. Just by doing so, the thermal fuse for detecting a new article cannot be easily separated from the outside, thereby prohibiting intentional continuous use.

Further, in claim 9, claims 1, 2, 3,
In the fixing device according to any one of 4, 5, 6, 7 and 8, the thermal fuse side for detecting a new product held by the holding member and the unit cover side are connected by a connector to fix the fixing device. By facilitating the replacement of the above-mentioned new temperature fuse for repair, at the time of repairing (regenerating) the unit, the new temperature fuse for detection of a new product can be easily replaced, thereby improving the efficiency of the replacement work.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. << Example of Embodiment Corresponding to Claim 1 >> FIG. 1 is a circuit diagram showing an example of an embodiment of the fixing device according to the present invention and a control circuit for controlling the fixing device. FIG. 2 is an example of an embodiment of the fixing device shown in FIG. It is a schematic block diagram which shows. The control circuit 1 shown in FIG. 1 is connected to a power supply line 5 and a CPU circuit 3 for performing temperature control management of the fixing device 2, an EEPROM circuit 4 provided with a maintenance counter for indicating the number of times the fixing device 2 has been used, and the like. The resistor which is connected in series between the thermistor 6 of the fixing device 2 and the ground point, generates a temperature detection signal according to the temperature detected by the thermistor 6, and supplies this to the AN terminal of the CPU circuit 3. 7 and a FUCHG signal indicating whether or not the new-state detection temperature fuse 8 is blown, which is connected in series between the power-supply line 9 and the new-state detection temperature fuse 8 of the fixing device 2 connected to the ground point. The commercial power supply 1 is generated based on the resistor 10 which is generated and supplied to the FUCHG terminal of the CPU circuit 3 and the ON / OFF signal output from the HTON terminal of the CPU circuit 3. Commercial voltage supplied by the on / off from and connected to the overheat preventing thermal fuse 12 of the fixing device 2 in series heater 13
And a triac 14 for heating the heating roller 15 shown in FIG.

When the image forming apparatus 16 in which the fixing device 2 is set is powered on, the fixing device is based on the value (signal level) of the FUCHG signal output from the thermal fuse 8 for detecting a new product by the CPU circuit 3. It is determined whether or not 2 is a new product, and when it is a new product, the maintenance counter provided in the EEPROM circuit 4 is initialized. Thereafter, the CPU circuit 3 increments the maintenance counter to start monitoring the number of times the fixing device 2 is used, the time used, and the like.
Based on the temperature detection signal output from the thermistor 6 of the fixing device 2, PI calculation or the like is performed to generate an on / off signal, and based on this on / off signal,
The triac 14 is controlled to be turned on / off, a voltage is applied to the heater 13 of the fixing device 2, and the temperature of the heating roller 15 is set to a preset value. In this case, the fixing device 2 is the sheet 1 on which the toner image is formed as shown in FIG.
The heating roller unit 18 is arranged on the upper side of the conveying path along which the 7 is conveyed, and the pressure roller unit 19 is arranged on the lower side of the conveying path. The pressing roller 20 presses the sheet 17 conveyed along the conveying path against the heating roller 15 in the heating roller unit 18, while the heat of the heating roller 15 causes the toner image formed on the sheet 17 to be transferred. Is melted and fixed.

The pressure roller unit 19 has a box-shaped unit cover 22 in which a constricted portion 21 formed in a portion facing the transport path serves as a transport guide, and faces the transport path in the unit cover 22. It is equipped with a pressure roller 20 that is vertically movable at a location and a spring (not shown) that biases the pressure roller 20 toward the heating roller 15 side, and is conveyed along a conveyance path. The paper 17 received is taken in and pressed against the heating roller 15. The heating roller unit 18 includes a box-shaped unit cover 24 in which a constricted portion 23 formed in a portion facing the transport path serves as a transport guide, and the unit cover 2
4, a heating roller 15 which is arranged at a position facing the conveyance path and is heated by a heater 13 arranged inside and melts the toner on the paper 17 pressed by the pressure roller 20; The paper 17 which is arranged in the cover 24 close to the heating roller 15 and is heated by the heating roller 15 is the heating roller 1.
5, a separating claw 25 for preventing the winding from being wound around the thermistor 5, a thermistor 6 arranged in the unit cover 24 in the vicinity of the heating roller 15, and a thermal fuse for detecting a new product arranged in an upper side of the unit cover 24. 8 and an overheat preventing temperature fuse 12 arranged at a predetermined position in the unit cover 24. When the fixing device 2 is a new one, it indicates that the new detecting temperature fuse 8 is not blown. A FUCHG signal (“L” level signal) is output to inform the CPU circuit 3 that the fixing device 2 is a new product, the fixing device 2 is used even once, and the new product detection temperature fuse 8 is blown. When the fixing device 2 is in use, the FUCHG signal is set to the "H" level to notify that the fixing device 2 is in use. The temperature of the heating roller 15 is detected by the thermistor 6, and the temperature detection signal obtained thereby is supplied to the control circuit 1. At the same time, the commercial voltage output from the control circuit 1 causes the heater 13 to generate heat so that the heating roller 15 is heated. While maintaining the temperature at a predetermined value, the paper 17 pressed by the pressure roller 20 is heated to melt the toner image formed on the paper 17 and fix it on the paper 17. . At this time, the fusing temperature of the new-article detection temperature fuse 8 depends on conditions such as the installation position and the temperature gradient near the heating roller 15.
An appropriate value is selected, but at least to prevent accidental blowout before use and to ensure reliable blowout after use,
The temperature in the fixing device 2 or the temperature in the image forming device 16 in which the fixing device 2 is set is higher than the higher temperature by 10 ° C. or more and is higher than the surface temperature (fixing temperature) of the heating roller 15. Also, it is desirable that the value be 10 ° C. or lower.

As described above, in this embodiment, the heating roller 1
When a new fixing device 2 is set in the image forming apparatus 16, a thermal fuse 8 for detecting a new article is arranged on the upper part of the No. 5, and the temperature fuse 8 for detecting a new article is an "L" level FUCHG. A signal is generated and transmitted to the CPU circuit 3 of the control circuit 1 to initialize the maintenance counter of the EEPROM circuit 4, after which the heater 13 of the heating roller 15 is energized and the temperature of the heating roller 15 rises. , When the temperature of the new-state detecting thermal fuse 8 becomes equal to or higher than the fusing temperature, and the fusing temperature is blown, the FUCHG at the “H” level indicating that the fixing device 2 is in use
Since the signal is generated and transmitted to the CPU circuit 3 of the control circuit 1, the new-article detection temperature fuse 8 can be blown without the need for a special fusing circuit, thereby increasing the cost. While keeping the pressure low, the CPU circuit 3 is made sure to know the replacement time of the fixing device 2 and the like, and the display device (not shown) of the image forming device 16 is shown.
It is possible to display the replacement time of the fixing device 2 on the display, and to perform the replacement work of the fixing device 2 before the image quality deteriorates.

In this embodiment, as shown in FIG. 1, the thermal fuse 8 for detecting a new article is provided in the fixing device 2.
Via the terminals 28 and 29 to the resistor 10 of the control circuit 1,
Although each of them is connected to the ground point, a resistor for voltage division is connected between the resistor 10 arranged in the control circuit 1 and the ground point, and when the fixing device 2 is not mounted, A voltage signal indicating that the fixing device 2 is not connected is generated at the connection point of each of the resistors 10, and when the fixing device 2 is mounted, the connection point of each resistor 10 is for detecting the new product. A FUCHG signal indicating whether or not the thermal fuse 8 is blown is generated, the AN terminal of the CPU circuit 3 directly monitors this, or a comparator is used to convert the signal to a 2-bit signal. You may make it monitor. By doing this, the CPU
A signal input to the AN terminal of the circuit 3 can be used to detect whether the fixing device 2 is mounted or not and detect a new product.

<< Example of Embodiment Corresponding to Claim 2 >> As described above, the replacement of the fixing device 2 is detected. At this time, the on-timing of the heater 13 is important. That is, the temperature fuse 8 for detecting a new article is set to the above-mentioned fusing temperature, and is sensitive to the temperature rise of the fixing device 2. For this reason, if the heater 13 is turned on before the output (FUCHG signal) of the new-state detection temperature fuse 8 is detected, the old fixing device 2 is determined even though the new fixing device 2 is installed. It can also happen. Therefore, in the present invention, the fixing device 2 is controlled by the procedure shown in the flowchart of FIG. First, when the CPU circuit 3 performs initialization after power-on (steps ST1 and ST2),
It is determined whether the cover is closed (step ST3). If the cover of the image forming apparatus 16 is closed, FUCH
The level of the G signal is checked (step ST4).
If this FUCHG signal is at "L" level,
When it is determined that a new fixing device 2 is installed, EEPRO
The value of the maintenance counter stored in the M circuit 4 is initialized (step ST5), and after the initialization processing is finished, the energization control to the heater 13 is started (step S).
T6). If the fixing device 2 is not new, the CPU circuit 3 skips the initialization processing of the maintenance counter and shifts to the control operation of the heater 13 (step ST
6). The operation after the cover is opened / closed is performed in the same manner as the control after the initialization described above. By controlling the fixing device 2 in such a procedure, it is possible to prevent erroneous fusing of the new-state detection temperature fuse 8 due to the energization of the heater 13.

<Example of Embodiment Corresponding to Claim 3> Further, the problem due to excessive use of the fixing device 2 is as described above, but in the present invention, in order to prevent this, the procedure shown in the flowchart of FIG. 4 is carried out. Then, the fixing device 2 is controlled. That is, the CPU circuit 3 initializes the value of the maintenance counter stored in the EEPROM circuit 4 every time when the fixing device 2 is replaced, and the currently used fixing device 2 is removed to replace the fixing device 2 with a new one. Until the fixing device 2 is set, the value of the maintenance counter is incremented according to the usage time or the number of printed sheets (step ST11). Then, when the value of the maintenance counter reaches the first preset value (step ST12), a message prompting the replacement of the fixing device 2 is displayed on the display device (not shown) of the image forming device 16 in which the fixing device 2 is mounted. Is displayed, or the controller of the image generation device 16 is notified that the replacement time has come (step ST13). After that, when the fixing device 2 is continuously used without replacing the fixing device 2, the value of the maintenance counter is incremented according to the usage time or the number of printed sheets. Exceeds the second predetermined value (step ST14),
It is determined whether or not the print processing is currently being performed, and if the print processing is being performed, the job currently being executed is continued until the end of the current job (step ST15). When the job is not being executed or when the job is completed (step ST1
5) Then, the subsequent image formation is stopped, and information indicating that the image formation is stopped is sent to the display device or the controller (steps ST16 and ST17). By doing so, it is possible to prevent the fixing device 2 from being excessively used and to prevent a marked deterioration in print quality. On this occasion,
The value (width) between the first default value and the second default value is preferably set to be equal to or less than the maximum number of sheets that can be fed by the image forming apparatus 16 or time. Further, even when the machine is stopped at the paper end when the second preset value is exceeded, if the job is in the middle of the job, the image forming operation is forcibly performed after the paper is supplied and until the job is completed. Don't let it stop.

<< Example of Embodiment Corresponding to Claim 4 >> In the present invention, the installation position of the temperature fuse 8 for detecting a new product is
Basically, it may be installed anywhere inside the fixing device 2, but as shown in FIG. 1, it is most efficient to install it in the vicinity of the upper part of the heating roller 15, and the selection of the fusing temperature is compared. It is especially effective because it can be loosened. Further, when the heating roller 15 is arranged below the pressure roller 20, it is more efficient to install the new product detection temperature fuse 8 below the roller nip position. Since 8 can be blown out, it is effective to install it at this position.

<Example of Embodiment Corresponding to Claim 5> Further, in order to enhance the fusing property of the new-state detection thermal fuse 8, a heat-absorbing member containing carbon or the like or a heat-resistant black paint is applied to the surface of the new-state detection thermal fuse 8. Applying is also effective. By doing so, even if the new-article detection temperature fuse 8 is arranged in a region where the thermal efficiency is particularly low, it is possible to relatively easily obtain a reliable fusing characteristic of the new-article detection temperature fuse 8.

<< Example of Embodiment Corresponding to Claim 6 >> In addition, when the heater 13 provided on the heating roller 15 is actually energized at the time of manufacture to check this, the temperature fuse 8 for detecting a new article is checked at the time of checking. Since it is necessary to prevent the fusing, it is possible to deal with this by using the configuration shown in FIG. In this case, a groove 30 is formed in the upper portion of the unit cover 24 which constitutes the heating roller unit 18 of the fixing device 2, and the slider 31 is slidably inserted into the groove 30 and the unit cover 2
The L-shaped heat insulating member 32 is arranged in the
A heat insulating mechanism 33 is provided in which the upper part of 2 is integrated with the lower part of the slider 31. When the unit check of the fixing device 2 is performed, the slider 31 is positioned at the position A as shown in FIG.
The heat insulating member 32 between the heating roller 15 and
The heat of the heating roller 15 is blocked by the heat insulating member 32 so that the new-state detecting temperature fuse 8 is not blown. After that, even when the heat insulating member 32 remains in the position A, when the fixing device 2 is mounted on the image forming apparatus 16 as shown in FIG. The upper protrusion 34 abuts the housing 35 of the image forming apparatus 16, whereby the movement of the slider 31 is regulated and the slider 31 is moved along the groove 30. Then, as shown in FIG. 6C, the fixing device 2 is replaced with the image forming device 1.
When the drive gear 37 which is set to the fixed position 6 and works in conjunction with the jam clearance knob 36 meshes with the gear (not shown) on the image forming apparatus 16 side, the slider 31 is fixed at the position B. Then, when the heater 13 is energized, the heat of the heating roller 15 melts the thermal fuse 8 for detecting a new product. In addition, in this embodiment, since the new-article detecting temperature fuse 8 is arranged on the upper portion of the unit cover 24, the groove 30 is provided on the upper portion of the unit cover 24. Depending on the situation, the position of the groove 30 may be set appropriately.

<< Example of Embodiment Corresponding to Claim 7 >> As another method, a configuration as shown in FIG. 7A may be adopted. In this case, a hole 40 having a predetermined shape is formed in the upper part of the unit cover 24, and a holding member 41 for opening and closing the hole 40 is rotatably attached to the upper part of the unit cover 24. When the fixing device 2 is checked by attaching the new-state detection thermal fuse 8 to the lower surface side of the printer, heat is not applied to the new-state detection thermal fuse 8 by opening the holding member 41 and energizing the heater 13. In this way, prevent accidental melting,
When the fixing device 2 is set in the image forming device 16, when the fixing device 2 is set in FIG.
As shown in (b), the holding member 41 is fitted in the hole 40 of the unit cover 24, the new-article detection temperature fuse 8 is positioned immediately above the heating roller 15, and the heater 13 is energized to heat the heating roller 15. At this time, this heat causes the thermal fuse 8 for detecting a new product to be blown. By doing so, it is possible to prevent the thermal fuse 8 for detecting a new product from being erroneously blown when the unit check of the fixing device 2 is performed. Although the release angle of the holding member 41 is about 90 degrees in FIG. 7A, it is preferable to make this angle an obtuse angle.

As another method, the structure shown in FIG. 8A may be used. In this case, the unit cover 2
4, a hole 43 having a predetermined shape is formed, and a holding member 44 for opening and closing the hole 43 is arranged separately from the unit cover 24, and a thermal fuse for detecting a new product is provided on the lower surface side of the holding member 44. When the fixing device 2 is checked by attaching 8, the heater 13 is energized with the holding member 44 removed from the unit cover 24 so that heat is not applied to the new-article detection temperature fuse 8. When the fixing device 2 is set in the image forming device 16 to prevent accidental fusing, the holding member 44 is fitted into the hole 43 of the unit cover 24 as shown in FIG. The heater 13 is positioned immediately above the roller 15 and the heater 13 is energized to heat the roller 15.
When the product is heated, this heat causes the temperature fuse 8 for new product detection.
Melt down. Even in this case, when the unit check of the fixing device 2 is performed, the temperature fuse 8 for detecting a new article is used.
Can be prevented from being cut by mistake.

<Example of Embodiment Corresponding to Claim 8> Furthermore, in order to improve the reliability of new article detection, it is also important that the fixing device 2 that has been used once is made new by the user side so that it cannot be used. . Therefore, in the present invention, as shown in FIG.
As shown in FIG. 8, hooks 45 and 46 are formed at one end or both ends of holding members 41 and 44 that open and close the holes 40 and 43 of the unit cover 24, and the holding members 41 and 44 are formed into the holes 40 and 40 of the unit cover 24. When it is fitted in the unit 43, the hooks 45, 46 are caught by the protrusions 47, 48 formed around the holes 40, 43 of the unit cover 24 (by engaging the patchons), and the holding member 41, the unit cover 24.
44 and the unit cover 2
4 and the holding members 41, 44 are flush with each other,
The hooks 45 and 46 of the holding members 41 and 44 cannot be pushed out from the outside. As a result, the user side can be prevented from replacing the new-article detection temperature fuse 8 provided in the fixing device 2. Although not shown, the same effect can be obtained even if the holding members 41 and 44 are fixed from the back side of the unit cover 24 by fixing means such as screws.

<< Example of Embodiment Corresponding to Claim 9 >> Further, when the fixing device 2 is repaired at a repair center or the like and reused, it is important that the thermal fuse 8 for new article detection can be easily replaced. Is an element. In this regard, according to the present invention, when the unit cover 24 constituting the heating roller unit 18 of the fixing device 2 is removed, the holding member 4 is arranged from the inside.
1, 44 can be easily removed, so that when repairing the used fixing device 2 at a repair center or the like, the thermal fuse 8 for detecting a new product attached to the holding members 41, 44 is used.
Can be easily replaced and repair work can be facilitated. Although not shown, the harness on the holding members 41 and 44 side and the harness on the unit cover 24 side are connected by electrical contacts such as a connector to further improve the work efficiency during repair. Is also good.

[0025]

As described above, according to the present invention, in claim 1, the temperature fuse is used as the new article detecting means, thereby eliminating the need for a special fusing circuit.
It is possible to change the state of the above-mentioned new article detecting means, thereby making it possible to surely know the replacement time of the fixing device etc. while suppressing the cost increase, and to perform the replacement work etc. before the image quality deteriorates. be able to.
In addition, in the second aspect, by starting to energize the heater after detecting whether or not the new-arts detection temperature fuse is blown, it is possible to prevent erroneous blow-out of the new-article detection temperature fuse due to energization of the heater. Therefore, it is possible to prevent an erroneous determination from occurring when determining whether the product is new.

Further, in claim 3, even if the default value is exceeded,
By stopping the image forming operation when the fixing device or the like is not replaced, it is possible to prevent machine damage due to the occurrence of a defect and waste of paper due to defective printing. Further, according to the present invention, by installing the thermal fuse for detecting a new article on the upper part of the heating roller, it is possible to improve the thermal efficiency and surely blow the thermal fuse for detecting a new article when the heater is energized. Therefore, it is possible to prevent an erroneous determination from occurring when determining whether the product is new.

Further, according to the present invention, by performing heat-absorbing heat treatment on the surface of the new-state detection thermal fuse, even if the new-state detection thermal fuse is installed in a place where thermal efficiency is poor, when the heater is energized, the new-state detection thermal fuse is detected. The temperature fuse for use can be surely blown, and this can prevent an erroneous determination from occurring when determining whether the product is new. In addition, according to the present invention, an insulating member is inserted between the heating roller and the temperature fuse for detecting a new product before or other than when the image forming apparatus is mounted on the image forming apparatus. It is possible to prevent the thermal fuse for detecting a new product from being blown out before or other than when it is mounted.

Further, in the present invention, by making the unit cover and the temperature detection fuse holding member for new article detection separable, the temperature fuse for new article detection is isolated at the time of unit check, and the temperature fuse for new article detection is erroneously blown. Can be prevented. Further, according to claim 8, it is possible to prevent the new-state detection temperature fuse from being easily separated from the outside simply by setting the new-state detection temperature-fuse holding member on the unit cover after the unit check. The use can be prohibited. Further, in claim 9, by connecting the fixing device main body and the new-article detection temperature fuse with a connector, the new-article detection temperature fuse can be easily replaced when the unit is repaired (regenerated). Work efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a form example of claim 1 of the form examples of a fixing device and a control circuit for controlling the fixing device according to the present invention.

FIG. 2 is a schematic configuration diagram showing one form example of the fixing device shown in FIG.

FIG. 3 is a flowchart showing a form example of claim 2 of the form examples of the fixing device and the control circuit for controlling the fixing device according to the present invention.

FIG. 4 is a flowchart showing a form example of claim 3 of the form examples of the fixing device and the control circuit for controlling the fixing device according to the present invention.

FIG. 5 is a schematic configuration diagram showing a form example of claim 6 among the form examples of the fixing device and the control circuit for controlling the fixing device according to the present invention.

6A, 6B, and 6C are schematic diagrams illustrating a unit check operation of the fixing device illustrated in FIG. 5 and an operation example when the fixing device is attached to the image forming apparatus.

7 (a) and 7 (b) are views showing one example of a fixing device according to the present invention and a control circuit for controlling the fixing device.
It is a schematic block diagram which shows the example of a form of Claim 7.

8A and 8B are views showing one example of a fixing device according to the present invention and a control circuit for controlling the fixing device.
It is a schematic block diagram which shows the example of a form of Claim 7.

[Explanation of Codes] 1 ... Control circuit, 2 ... Fixing device, 3 ... CPU circuit (control unit, detection unit), 4 ... EEPROM circuit (maintenance counter), 5 ... Power supply line, 6 ... Thermistor (temperature measurement unit), 7 ... Resistance, 8 ... New product detection temperature fuse, 9 ... Power supply line, 10 ... Resistance, 11 ... Commercial power supply, 12 ... Overheat prevention temperature fuse, 13 ... Heater, 14 ... Triac, 15 ... Heating roller, 16 ... Image Forming device, 17 ... Paper, 18 ... Heating roller unit, 19 ... Pressure roller unit, 20 ... Pressure roller, 21 ... Constricted portion, 22 ... Unit cover, 23 ... Constricted portion, 24 ... Unit cover,
25 ... Separation claw, 28, 29 ... Terminal, 30 ... Groove, 31 ... Slider, 32 ... Insulation member, 33 ... Insulation mechanism, 35 ... Case, 36 ... Knob, 37 ... Drive gear, 40 ... Hole, 41 ... Holding Member, 43 ... Hole, 44 ... Holding member, 45, 46 ... Hook (locking part), 47, 48 ... Convex part (locking part)

Claims (9)

[Claims] 1. A heating roller that heats a sheet on which a toner image is formed, and a pressure roller that presses the sheet against the heating roller while heating the sheet while conveying the sheet at a narrow pressure,
In a roll-type fixing device for fixing the toner image on the paper, a new-article detection temperature fuse that is blown by secondary heat or convection heat from the heating roller is provided. A fixing device characterized by determining whether or not the fixing device is new based on whether or not the fixing device is new. 2. A temperature measuring unit for measuring the temperature of the fixing device, a control unit for controlling a heater provided on the heating roller based on temperature information obtained by the temperature measuring unit, and the use of the fixing device. The fixing device is controlled by a control circuit equipped with a maintenance counter that counts the amount or time of use and a detection unit that detects the state of the new-state detection temperature fuse, and the detection unit detects that the fixing device is new. Then, in the fixing device control method for initializing the maintenance counter, the state of the new-state detection temperature fuse is detected by the detection unit after the power is turned on or after the cover is closed, and it is determined whether or not it is a new one. Thereafter, the heater of the fixing device is started to be energized to heat the heating roller, which is a method for controlling the fixing device. 3. A method of controlling an image forming apparatus for controlling the fixing device to perform a fixing operation when the fixing device is set, wherein the fixing device is reset when the fixing device is new, and thereafter, the fixing device is reset. When the value of the maintenance counter, which is incremented according to the use time or the number of times of use, exceeds the first preset value, a replacement request is issued, and even when the second preset value is reached, replacement is not detected, the image forming operation is performed. A method for controlling an image forming apparatus, characterized by stopping. 4. The fixing device according to claim 1, wherein the new-state detecting temperature fuse is installed at a position directly above the heating roller or in the vicinity of the position directly above the heating roller. Fixing device. 5. The fixing device according to any one of claims 1, 2, 3, and 4, wherein a heat absorbing member that easily absorbs secondary radiation heat and convection heat is applied to the surface of the new-article detection temperature fuse. Characterizing fixing device. 6. The fixing device according to claim 1, wherein between the heating roller and the thermal fuse for detecting a new product at the time of operation check when the fixing device is manufactured. A heat insulating member is arranged to prevent erroneous fusing, and when the fixing device is set in the image forming apparatus, the heat insulating member is removed from between the heating roller and the temperature fuse for detecting a new product to enable fusing. A fixing device characterized by the above. 7. The fixing device according to claim 1, further comprising a unit cover that constitutes the fixing device and a holding member that holds the new-state detecting temperature fuse. It is constituted by a separate member, and at the time of operation check when the fixing device is manufactured, the holding member is separated or opened from the unit cover to prevent erroneous fusing of the new-state detection temperature fuse. Fixing device. 8. The fixing device according to claim 1, 2, 3, 4, 5, 6, or 7, wherein the holding member locks the holding member when set on the unit cover. And a locking portion of the unit cover are engaged with each other inside the unit cover, and the engagement of the locking portions cannot be released from the outside of the unit cover. . 9. The method of claim 1, 2, 3, 4, 5, 6, 7, or 8.
In the fixing device according to any one of 1 to 3, when the temperature fuse side for detecting a new product held by the holding member and the unit cover side are connected by a connector and the fixing device is repaired, the temperature for detecting a new product is set. A fixing device characterized by facilitating replacement of fuses.