JP3432066B2 - Fixing device, method of controlling fixing device, and method of controlling image forming apparatus - Google Patents

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, and by using a temperature fuse as a new article detecting means, the state of the new article detecting means can be changed without requiring a special fusing circuit. A fixing device capable of reliably grasping the replacement time of the fixing device and the like while keeping the cost rise low and performing the replacement work before the image quality deteriorates. Is intended. In addition, after detecting whether or not the new product detection temperature fuse is blown, the heater energization is started to prevent erroneous fusing of the new product detection temperature fuse due to energization of the heater, and An object of the present invention is to provide a fixing device control method capable of preventing erroneous judgments from being made when making a judgment. In addition, even if the fixing value is exceeded, if the fixing device or the like is not replaced, the image forming operation is stopped to prevent machine damage due to malfunction and waste of paper due to defective printing. An object of the present invention is to provide a method for controlling a forming device. In addition, by installing a new product detection temperature fuse on the heating roller, it is possible to improve the thermal efficiency and to reliably melt the new product detection temperature fuse when the heater is energized. An object of the present invention is to provide a fixing device capable of preventing an erroneous determination from occurring when determining whether or not to make a determination. In addition, by applying heat-absorbing heat treatment to the surface of the new-state detection temperature fuse, even if the new-state detection temperature fuse is installed in a location with poor thermal efficiency, when the heater is energized, the new-state detection temperature fuse is surely blown out. Therefore, 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 or not. In addition, before or other than before being attached to the image forming apparatus, by inserting a heat insulating member between the heating roller and the thermal fuse for detecting a new product, before attaching to the image forming apparatus, such as at the time of unit check. An object of the present invention is to provide a fixing device that can prevent the thermal fuse for detecting a new product from being blown out in other cases. Also, by making the unit cover and the new temperature detection fuse holding member separable, the new temperature detection fuse can be isolated when the unit is checked to prevent the new temperature detection fuse from being accidentally blown. An object of the present invention is to provide a fixing device that can be used. In addition, 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 checking the unit, thereby prohibiting intentional continuous use. It is an object of the present invention to provide a fixing device capable of Also, by connecting the fixing device body and the thermal fuse for detecting new products with a connector, when repairing the unit (when regenerating)
Another object of the present invention is to provide a fixing device capable of facilitating the replacement of the new temperature fuse for detecting a new product and thereby improving the efficiency of the replacement work.

[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 The temperature fuse and the control unit that determines whether or not the fixing device is new based on whether or not the new-state detection temperature fuse is blown, and the heating roller and the new product when checking the operation when the fixing device is manufactured. It is arranged between the temperature fuse for detection to prevent accidental fusing of the temperature fuse for new product detection, and when the fixing device is set in the image forming apparatus, the heating roller and the new temperature detection device are used. To the exclusion from between the time fuse,
A heat insulating member capable of fusing the new product detecting temperature fuse, and positioning the heat insulating member between the heating roller and the new product detecting temperature fuse during the operation check,
It is characterized in that it is provided with a heat insulating mechanism capable of fixing the heat insulating member at a position excluded from the position at the time of the operation check when set in the image forming apparatus. According to a second aspect of the present invention, in the method for controlling the fixing device according to the first aspect, the heating roller is provided on the basis of a temperature measuring unit that measures the temperature of the fixing device and temperature information obtained by the temperature measuring unit. The fixing device is controlled by a control circuit that includes a controller that controls the heater, a maintenance counter that counts the usage amount or usage time of the fixing device, and a detection unit that detects the state of the temperature fuse for detecting a new product. A method of controlling a fixing device, wherein the maintenance counter is initialized when the fixing device detects that the fixing device is new, and a temperature for detecting a new product is detected by the detecting unit after the power is turned on or the cover is closed. After detecting the state of the fuse and judging whether it is new or not,
The heater of the fixing device is energized to heat the heating roller. According to a third aspect of the present invention, in the image forming apparatus control method for controlling the fixing device to perform the fixing operation when the fixing device according to the first aspect is set, when the fixing device is new, When the value of the maintenance counter, which is reset and subsequently 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 even if the second preset value is reached, replacement is performed. The feature is that the image forming operation is stopped when it is not detected. According to a fourth aspect of the present invention, in the fixing device according to the first aspect, 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 of the present invention, in the fixing device according to the first aspect, a secondary heat is applied to the surface of the new-article detecting temperature fuse,
The feature is that a heat absorbing member that easily absorbs convective heat is applied. According to a sixth aspect of the present invention, in the fixing device according to any one of the first to fourth aspects, the unit cover that constitutes the fixing device and the holding member that holds the thermal fuse for detecting a new product are formed as separate members. However, 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 temperature detecting fuse. According to a seventh aspect of the present invention, in the fixing device according to the sixth aspect, when the holding member is set on the unit cover, the holding portion of the holding member and the holding portion of the unit cover are provided in the unit. It is characterized in that the engagement of the respective locking portions cannot be released from the outside of the unit cover by engaging them inside the cover. According to claim 8, in the fixing device according to any one of claims 6 and 7, the new-article detection temperature fuse side held by the holding member and the unit cover side are connected by a connector, When repairing the fixing device, it is easy to replace the thermal fuse for detecting a new product.

With the above structure, the heating roller that heats the sheet on which the toner image is formed and the pressure roller that presses the sheet against the heating roller heats the sheet while conveying the sheet at a narrow pressure, so that the toner image is formed. In the roll-type fixing device for fixing the sheet on the above-mentioned paper, a temperature sensor for detecting a new article that is blown by the secondary heat or convection heat from the heating roller is provided. By determining whether or not the fixing device is a new one, the state of the above-mentioned temperature fuse for detecting a new product is changed without the need for a special fusing circuit, thereby suppressing the cost increase and fixing device. Make sure to know the replacement time, etc., and perform the replacement work before the image quality deteriorates. In addition, 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, the usage amount or use of the fixing device. When the fixing device is controlled by the control circuit having a maintenance counter that counts time 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, 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 the cover is closed,
After determining whether the product is new or not, the heater of the fixing device is energized to heat the heating roller to prevent accidental fusing of the temperature fuse for new product detection due to energization of the heater. When making a decision as to whether or not to make a decision, it is possible to prevent an erroneous decision from occurring.

When the fixing device is set,
In a method of controlling an image forming apparatus that controls the fixing device to perform a fixing operation, when the fixing device is new,
When the value of the maintenance counter, which is reset and subsequently 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 even if the second preset value is reached, replacement is performed. When not detected,
By stopping the image forming operation, when the fixing device is not replaced even after the default value is exceeded, the image forming operation is stopped to prevent machine damage due to malfunction and waste of paper due to defective printing. To prevent. Further, by installing the new-state detection thermal fuse directly above the heating roller or in the vicinity thereof, the thermal efficiency is improved, and when the heater is energized, the new-state detection thermal fuse is installed. It is surely blown to prevent erroneous judgment when judging whether it is new or not.

Further, by coating the surface of the above-mentioned new-article temperature detecting fuse with a heat absorbing member that easily absorbs secondary heat and convective heat, even if the new-state detecting thermal fuse is installed in a place where thermal efficiency is poor, the heater will not When energized, the thermal fuse for detecting a new product is surely blown to prevent an erroneous judgment when judging whether the product is new or not. When the fixing device is set in the image forming apparatus, a heat insulating member is disposed between the heating roller and the new-state detection temperature fuse during operation check when the fixing device is manufactured to prevent accidental fusing. , By removing the heat insulating member between the heating roller and the thermal fuse for detecting a new product so that the fuse can be blown, for detecting a new product before or other than when it is mounted in the image forming apparatus, such as during unit check. Prevent the thermal fuse from being blown.

Further, the unit cover constituting the fixing device and the holding member for holding the thermal fuse for detecting the new article are formed as separate members, and the unit cover holds the holding member at the time of operation check when the fixing device is manufactured. By disconnecting or opening the unit to prevent accidental blowout of the above-mentioned new temperature detection fuse, the new detection temperature fuse is isolated during unit check, and the new detection temperature fuse is not blown by mistake. Prevent. When the holding member is set on the unit cover, the locking portion of the holding member and the locking portion of the unit cover are engaged with each other inside the unit cover so that the outside of the unit cover. Therefore, by making it impossible to release the engagement of each of the above-mentioned locking parts, it is not possible to easily separate the new-state detection temperature fuse from the outside simply by setting the new-state detection temperature-fuse holding member on the unit cover after the unit check. This prohibits intentional continuous use.

Further, when the fixing device is repaired by connecting the unit cover side with the new-article detection temperature fuse held by the holding member with a connector, the new-article detection temperature fuse can be easily replaced. By doing so, it becomes easy to replace the new-state detection temperature fuse when the unit is repaired (regenerated), thereby improving the efficiency of the replacement work.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail based on the embodiments shown in the drawings. FIG. 1 is a circuit diagram showing a form example of a fixing device according to the present invention and a control circuit for controlling the fixing device, and FIG. 2 is a schematic configuration diagram showing a form example of the fixing device shown in FIG. 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.

In this way, the replacement of the fixing device 2 is detected, but 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. Therefore, if the heater 13 is turned on before the output (FUCHG signal) of the new-state detecting thermal fuse 8 is detected, the old fixing device 2 will be installed even though the new fixing device 2 is installed.
It may be judged that. Therefore, in the present invention, the procedure shown in the flowchart of FIG.
The fixing device 2 is controlled. First, when the CPU circuit 3 performs initialization (initialization) after power is turned on (steps ST1 and ST2), it determines whether the cover is closed (step ST3), and if the cover of the image forming apparatus 16 is closed, The level of the FUCHG signal is checked (step ST4). If the FUCHG signal is at "L" level, it is determined that a new fixing device 2 has been installed, and the value of the maintenance counter stored in the EEPROM circuit 4 is initialized (step ST5).
After this initialization processing is completed, the energization control to the heater 13 is started (step ST6). If the fixing device 2 is not new, the CPU circuit 3 skips the maintenance counter initialization process and shifts to the control operation of the heater 13 (step ST6). In addition, cover open /
The operation after the closing is also performed in the same manner as the above-mentioned control after the initialization. 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.

Although the problem caused by the excessive use of the fixing device 2 is as described above, in the present invention, in order to prevent this, the fixing device 2 is controlled by the procedure shown in the flowchart of FIG. 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. Or the image generation device 16
The controller is notified that the replacement time has come (step ST13). After this, the fixing device 2
When the fixing device 2 is continuously used without being replaced, the value of the maintenance counter is incremented according to the usage time or the number of printed sheets, and the value of the maintenance counter becomes the second predetermined value. When it exceeds (step ST14), it is determined whether or not the print processing is currently being performed. If the print processing is being performed, the current job is continued until the end of the current job (step ST1).
5). When the job is not being executed or when the job is completed (step ST15), the subsequent image formation is stopped and the information indicating that the image formation is stopped is sent to the display device or the controller (steps ST16, S).
T17). 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. At this time, the value (width) between the first preset value and the second preset 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.

Further, according to the present invention, the temperature detecting fuse 8 for detecting a new article may be basically installed anywhere inside the fixing device 2, but as shown in FIG. It is particularly effective to install it in the vicinity of the upper part of, because the thermal efficiency is the best and the fusing temperature can be selected relatively loosely. Further, the heating roller 15 is the pressure roller 20.
In the case where the new-state detection temperature fuse 8 is arranged below the roller nip position, the new-state detection temperature fuse 8 can be efficiently melted and cut. It is effective to install it in a position.

Further, in order to improve the fusing characteristics of the new-article detection temperature fuse 8, it is also effective to apply a heat absorbing member containing carbon or the like or a heat-resistant black paint on the surface of the new-article detection temperature fuse 8. By doing so, the temperature fuse 8 for detecting a new product is especially attached to a portion having poor thermal efficiency.
Even with the above arrangement, the reliable fusing characteristic of the new-state detection temperature fuse 8 can be obtained relatively easily.

In addition, when the heater 13 provided on the heating roller 15 is actually energized at the time of manufacturing to check this, it is necessary to prevent the thermal fuse 8 for detecting a new product from being blown out at the time of checking. Therefore, the configuration shown in FIG. 5 may be used to handle this. In this case, a groove 30 is formed in an upper portion of a unit cover 24 that constitutes the heating roller unit 18 of the fixing device 2, a slider 31 is slidably inserted in the groove 30, and an L-shaped heat insulation is provided in the unit cover 24. Member 32
And the upper part of the heat insulating member 32 is attached to the slider 31.
The heat insulating mechanism 33 is provided integrally with the lower part of the. When performing the unit check of the fixing device 2, FIG.
Move the slider 31 to the position A as shown in FIG.
The heat insulating member 32 is positioned between the new product detecting temperature fuse 8 and the heating roller 15 so that the heat of the heating roller 15 is blocked by the heat insulating member 32 so that the new product detecting temperature fuse 8 is not blown. After that, even if the heat insulating member 32 remains in the position A portion, as shown in FIG.
When the image forming apparatus 16 is mounted on the image forming apparatus 16, the upper protrusion 34 of the slider 31 provided on the upper portion of the fixing device 2 abuts on the housing 35 of the image forming apparatus 16, whereby the movement of the slider 31 is restricted. The slider 31 is moved along the groove 30. Then, as shown in FIG. 6C, the fixing device 2 is set at a fixed position of the image forming apparatus 16, and a driving gear 37 that interlocks with the jam clearance knob 36 and a gear on the image forming apparatus 16 side (not shown). When you engage with
When the slider 31 is fixed to the position B and 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.

As another method, the structure shown in FIG. 7A may be used. In this case, the unit cover 2
4, a hole 40 having a predetermined shape is formed, and a holding member 41 for opening and closing the hole 40 is rotatably attached to the upper portion of the unit cover 24. When the fixing device 2 is checked by attaching the detection temperature fuse 8, the holding member 41 is opened and the heater 13 is energized so that heat is not applied to the new detection temperature fuse 8 and an error is detected. The fusing device is prevented and the fixing device 2 is attached to the image forming device 16
7b, the holding member 41 as shown in FIG.
Is inserted in the hole 40 of the unit cover 24, and the new-state detection temperature fuse 8 is positioned immediately above the heating roller 15,
When the heater 13 is energized and the heating roller 15 is heated, this heat causes the new-state detection temperature fuse 8 to melt.
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. Note that FIG.
Then, the release angle of the holding member 41 is set to about 90 degrees, but 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.

Further, 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, according to the present invention, as shown in FIGS. 7 and 8, a holding member 41 that closes the holes 40 and 43 of the unit cover 24 in an openable and closable manner.
Form hooks 45, 46 on one end or both ends of 44,
The holding members 41 and 44 are attached to the holes 40 and 4 of the unit cover 24.
3, the hooks 45 and 46 are provided with protrusions 47 and 48 formed around the holes 40 and 43 of the unit cover 24.
The holding members 41, 44 are prevented from coming off from the unit cover 24 by being caught on the upper surface of the unit cover 24 (holding the holding members 41, 44).
Of the holding members 41 and 44 are flush with the upper surface of the hook 4.
It is made impossible to push out 5, 46 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 holding members 41, 44 are provided from the back side of the unit cover 24.
Even if it is configured to fix with a fixing means such as a screw,
Similar effects can be obtained.

Further, when the fixing device 2 is repaired at a repair center or the like and reused, it is also an important factor that the new-arts detecting temperature fuse 8 can be easily replaced.
With respect to this point, in the present invention, when the unit cover 24 constituting the heating roller unit 18 of the fixing device 2 is removed, the holding members 41 and 44 can be easily removed from the inside, and therefore, the present invention has been used at a repair center or the like. When the fixing device 2 is repaired, it is possible to easily replace the new-article detection temperature fuse 8 attached to the holding members 41 and 44, and to facilitate the repair work. 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, by using the thermal fuse as the new article detecting means,
It is possible to change the state of the above-mentioned new article detection means without requiring a special fusing circuit, which makes it possible to grasp the replacement time of the fixing device etc. while keeping the cost rise low, and to improve the image quality. It is possible to carry out replacement work etc. before the deterioration. In addition, after detecting whether or not the new product detection temperature fuse is blown, the heater energization is started to prevent erroneous fusing of the new product detection temperature fuse due to energization of the heater, and When making a judgment, it is possible to prevent an erroneous judgment from occurring.

Further, 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 trouble and waste of paper due to defective printing. You can In addition, by installing a new product detection temperature fuse on the heating roller, it is possible to improve the thermal efficiency and to reliably melt the new product detection temperature fuse when the heater is energized. It is possible to prevent an erroneous determination from occurring when making a determination.

Further, by subjecting the surface of the new-arts detection thermal fuse to the heat-absorbing heat treatment, even if the new-arts detection thermal fuse is installed in a place where the thermal efficiency is low, the new-arts detection thermal fuse can be secured when the heater is energized. It is possible to prevent the erroneous judgment from occurring when judging whether the product is new or not. In addition, before or other than before being attached to the image forming apparatus, by inserting a heat insulating member between the heating roller and the thermal fuse for detecting a new product, before attaching to the image forming apparatus, such as at the time of unit check. In other cases, it is possible to prevent the thermal fuse for detecting a new article from being blown.

Further, by making the unit cover and the temperature detecting fuse holding member for new article separable, the temperature detecting fuse for new article is isolated at the time of unit check, and the temperature detecting fuse for new article is prevented from being blown by mistake. can do. In addition, 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 checking the unit, thereby prohibiting intentional continuous use. You can Further, by connecting the fixing device main body and the new-arts detection temperature fuse with a connector, it becomes easy to replace the new-parts detection thermal fuse when the unit is repaired (regenerated), thereby improving the efficiency of replacement work. be able to.

[Brief description of drawings]

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

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

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

FIGS. 8A and 8B are schematic configuration diagrams showing an example of a fixing device according to the present invention and a control circuit for controlling the fixing device.

[Explanation of symbols]

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 measuring unit), 7 ... Resistance, 8 ... new-use 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)

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (8)

(57) [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, whether the new-body detecting temperature fuse is blown by the secondary heat from the heating roller or the convective heat and whether the new-body detecting temperature fuse is blown based on whether a control unit that the fixing device to determine whether or not new, the operation check when the production of the fixing device, heat b
The new fuse by placing it between the
The fixing device prevents the thermal fuse for detection from being blown by mistake.
When set in the image forming device, the heating roller and new
Remove the product from the temperature fuse for product detection to
A heat insulating member that can blow the intelligent thermal fuse, the heating roller and the new product detection during the operation check.
The thermal insulation member is located between the thermal fuse and
From the position at the time of the operation check when setting in the forming device
A heat insulating mechanism that can fix the heat insulating member at a position to be excluded
Fixing device characterized in that it comprises a and. 2. A fixing device control method according to claim 1, wherein the heating roller is provided on the basis of a temperature measuring unit for measuring the temperature of the fixing device and temperature information obtained by the temperature measuring unit. The fixing device is controlled by a control circuit that includes a control unit that controls the heater, a maintenance counter that counts the usage amount or usage time of the fixing device, and a detection unit that detects the state of the temperature fuse for detecting a new product. A method of controlling a fixing device, which initializes the maintenance counter when the detection unit detects that the fixing device is new, wherein the detection unit detects a temperature fuse for a new product after the power is turned on or the cover is closed. After detecting the state and judging whether it is new or not, the heater of the fixing device is energized to heat the heating roller. The method of the fixing device to be. 3. A method of controlling an image forming apparatus for controlling the fixing device to perform a fixing operation when the fixing device according to claim 1 is set, wherein the fixing device is reset when the fixing device is new. 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. At this time, the control method of the image forming apparatus, characterized in that the image forming operation is stopped. 4. The fixing device according to claim 1, wherein the thermal fuse for detecting a new article is installed at a position directly above the heating roller or in the vicinity of the position directly above the heating roller. 5. The fixing device according to claim 1, wherein a heat absorbing member that easily absorbs secondary heat and convective heat is applied to the surface of the new-state detecting thermal fuse. 6. The fixing device according to claim 1 , wherein the unit cover forming the fixing device and a holding member for holding the new-state detecting temperature fuse are formed as separate members. A fixing device, characterized in that, during an operation check when the fixing device is manufactured, the holding member is separated or opened from the unit cover to prevent the thermal fuse for detecting a new article from being erroneously blown. 7. The fixing device according to claim 6 , wherein, when the holding member is set on the unit cover, the holding portion of the holding member and the holding portion of the unit cover are attached to the holding member of the unit cover. A fixing device characterized in that the engagement of each of the locking portions cannot be released from the outside of the unit cover by engaging with the inside. 8. The fixing device according to claim 6 , wherein the new-use detecting temperature fuse side held by the holding member and the unit cover side are connected by a connector. A fixing device, which facilitates replacement of the above-mentioned new-state detection temperature fuse when repairing.