JP2005156688A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve general purpose properties and safety of a fixing device used for an image forming apparatus. <P>SOLUTION: The image forming apparatusI can be selectively mounted with a 1st fixing device 10a and a 2nd fixing device 10b and includes an abnormality detecting circuit part 200, which calculates a plurality of temperature abnormality signals S11, S12, S21, S22, S31, S32, S41, and S42, based on the temperature detection signals from a plurality of temperature sensors NC1, NC2, TH3, and TH4 of a mounted fixing device and a stop signal arithmetic circuit 300, which calculates a power supply stop signal S<SB>off</SB>based upon the plurality of temperature abnormality signals; a fixing device setting signal Ss2 and a rack setting signal Ss3; and a temperature abnormality signal Se. Further, the apparatus is equipped with an identification signal output circuit, which outputs an identification signal Ss1 identifying the fixing device and an unnecessary signal invalidating circuit part 230 which invalidates signals unnecessary to calculate the power supply stop signal based upon the identification signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, and more particularly to a safety design of a fixing device.

The image forming apparatus is provided with a fixing device that fixes a toner image on a recording medium by heating. The fixing device includes a heating roller provided with a heating unit on the inside, and a pressure roller that presses the heating roller to form a nip portion.
When the temperature of the heating roller becomes excessive, it is necessary to cut off the power supply to the heating means by some method in order to prevent ignition of the heating roller and peripheral members.

  For example, when the heating roller is overheated, the temperature detection information from the temperature sensor is input to the control CPU and the temperature detection signal from the sensor is preset in order to cut off the power supply to the heating means. A fixing device is disclosed that cuts off power supply when the temperature exceeds a certain temperature (see Patent Document 1).

  However, when the control CPU goes out of control, the energization to the heating means cannot be interrupted, and therefore a signal for controlling the relay that interrupts the circuit is output based on the signal from the temperature measuring element that detects the temperature of the fixing roller. A thermal fixing control device that takes a logical sum of a CPU and a comparator that outputs a signal for controlling a relay based on a signal from a temperature sensing element and controls the relay by the output of the logical sum is disclosed (see Patent Document 2). ).

  Furthermore, if the detected temperature decreases after the power supply to the heating means is cut off, the heating means is turned on again. Therefore, if an abnormally high temperature is detected, the comparator cuts off the power supply to the heater regardless of the detected temperature thereafter. A recording apparatus having a forced heater disconnection circuit is disclosed (see Patent Document 3).

Also, as a method of double monitoring the fixing temperature (that is, the temperature of the heating roller), energization control of the fixing heater and on / off control of the power system are performed, and energization of the fixing heater is prohibited when a temperature abnormality is detected. And an MPU for turning off the power system power supply and an overtemperature detection / control means for forcibly turning off the power system power supply when the temperature of the fixing heater rises, and image for double monitoring the fixing temperature A forming apparatus is disclosed.
JP-A-5-197310 JP-A-5-307340 JP-A-8-262923 Japanese Patent Laid-Open No. 10-307514

However, conventionally, there is one temperature sensor that detects the temperature of the heating roller, and a method of forcibly stopping the heating means via a control unit such as a CPU based on a temperature detection signal from this temperature sensor is used. It has been. In this method, there is a case where the CPU cannot be stopped due to the control runaway of the CPU, and there is a concern in terms of safety. In addition to the temperature of the heating roller as a factor for interrupting the energization of the heating unit, it is preferable that the heating unit is heated only when there is no abnormality in the entire fixing device in consideration of various signals relating to the fixing device.
Further, in the case of an image forming apparatus in which a plurality of fixing devices having different heating means can be mounted, a fixing device may be mounted according to the usage environment of the image forming apparatus. In this case, it is necessary to configure a drive circuit and a peripheral circuit for each heating unit, and there is a concern about an increase in cost due to an increase in the number of components to be managed.
Furthermore, conventionally, a halogen lamp has been used as the heating means of the heating roller, but in recent years, an induction heater using an induction coil has been adopted as a high energy efficient heating means in order to save energy. Unlike the halogen lamp, the induction coil does not emit light even when it is energized, and the temperature rise rate is fast. Therefore, the operating state cannot be visually confirmed. For this reason, there is a risk of accidentally touching the heating roller during operation of the induction coil and causing burns, and there is also a risk of electric shock because the drive portion of the induction coil is at a high voltage.

  An object of the present invention is to improve the versatility and safety of a fixing device used in an image forming apparatus.

  The invention according to claim 1 can selectively mount a plurality of fixing devices having different heating means, and detects temperature at a plurality of detection positions of a heating member in the mounted fixing device; On-off control of the heating means by controlling the temperature abnormality detection means for detecting temperature abnormality at each detection position based on a plurality of detected temperature detection signals and the on-board fixing device. A control means for detecting a temperature abnormality based on a plurality of temperature detection signals, a blocking means for cutting off the power supply to the heating means, and a plurality of detected temperature abnormality signals And a stop signal output means for forcibly stopping the operation of the heating means based on the drive instruction signal or outputting a stop signal for instructing the shut-off means to the shut-off operation. An identification signal output means for outputting an identification signal for identifying the mounted fixing device, and an abnormal temperature signal unnecessary for the determination of the forced stop of the heating means based on the identification signal. And an unnecessary signal invalidating means for invalidating according to the fixing device.

  According to a second aspect of the present invention, the stop signal output means includes, in addition to the plurality of temperature abnormality signals, a pedestal set signal indicating a set state of the pedestal of the fixing device, and a fixing set indicating a set state of the fixing device. It is characterized in that a determination is made by using any one of a signal, a failure detection signal indicating a failure state of the temperature detection means, a connection detection signal indicating a connection state of a driving circuit of the fixing device, or a combination thereof.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the temperature detecting means is installed at one of the axially central portion and the end portion of the heating member or a combination thereof. It is characterized by being.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the temperature detection means is either a sensor that contacts the heating member or a sensor that does not contact the heating member. It is characterized by being composed of a combination of

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the temperature abnormality detection unit is configured such that the temperature abnormality of the heating member is either a high temperature abnormality or a low temperature abnormality. Or, both are detected.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the stop signal output unit is configured to perform the operation based on the plurality of temperature abnormality signals and the drive instruction signal. It is characterized in that the heating means is forcibly stopped by logically calculating a drive signal for turning on / off the heating means and outputting the drive signal to the driving means for driving the heating means.

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the stop signal output unit is configured to perform the operation based on the plurality of temperature abnormality signals and the drive instruction signal. A drive signal for turning on / off the heating means is calculated by logical operation and output to the control means, and the control means forcibly stops or shuts down the operation of the heating means based on the input drive signal. It is characterized by instructing the means to instruct a shut-off operation.

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the stop signal output means performs a logical operation on an abnormality detection signal based on the plurality of temperature abnormality signals. Calculated and output to the control means, the control means is configured to forcibly stop the operation of the heating means based on the input abnormality detection signal, or to instruct the cutoff means to shut off, It is characterized by.

  According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, the interruption means is in addition to a power supply interruption relay provided in a power supply path to the heating means, It is characterized by comprising either a thermostat or a thermal fuse or a combination thereof.

  A tenth aspect of the present invention is the image forming apparatus according to any one of the first to ninth aspects, wherein the heating means is a halogen heater, an electromagnetic induction heater, or a carbon heater. Yes.

  According to an eleventh aspect of the present invention, there is provided an image forming apparatus comprising: a driving unit that receives power supplied from a power source to drive the heating unit; and a heating member that is heated by the heating unit. It is characterized by comprising notifying means for notifying the operation state of the above.

  According to a twelfth aspect of the present invention, in the image forming apparatus according to any one of the first to tenth aspects, the image forming apparatus includes an informing unit that notifies an operating state of the heating unit.

  According to a thirteenth aspect of the present invention, in the image forming apparatus according to the eleventh or twelfth aspect, the informing means is provided in the vicinity of the fixing device or in the fixing device mount.

  According to a fourteenth aspect of the present invention, in the image forming apparatus according to the eleventh or twelfth aspect, the informing means is included in a display unit on which information relating to the image forming apparatus is displayed.

  According to a fifteenth aspect of the present invention, in the image forming apparatus according to any one of the eleventh to fourteenth aspects, the informing unit emits a semiconductor element (LED; Light Emitting Diode) or a liquid crystal display that emits light when an electric current is passed. (LCD; Liquid Crystal Display) or a combination thereof.

  According to the first aspect of the present invention, a plurality of types of fixing are provided by providing invalidating means for invalidating a temperature abnormality signal unnecessary for forced stop determination based on identification signals for identifying a plurality of fixing devices. Since an image forming apparatus capable of driving the apparatus (that is, a plurality of types of heating means) with the same circuit can be realized, it is not necessary to configure a drive circuit or a peripheral circuit for each heating means, and the number of components to be managed The cost can be expected to be reduced due to the reduction in image quality, and the versatility of the image forming apparatus can be improved.

  According to the second aspect of the present invention, the stop signal output means inputs, in addition to a plurality of temperature abnormality signals, any one of a gantry set signal, a fixing set signal, a failure detection signal, a connection detection signal, or a combination thereof. Therefore, the heating unit can be driven only when all the signals are normal, so that the safety of the image forming apparatus can be improved.

  According to the third aspect of the present invention, the temperature detection means can be either one of the axially central portion or the end portion of the heating member, or of those, as well as obtaining the same effect as the first or second aspect. By disposing at the combination position, it is possible to detect the temperature distribution abnormality in the axial direction of the heating member.

  According to the invention described in claim 4, the same effects as in any one of claims 1 to 3 can be obtained, and the adaptation of the present invention can be applied regardless of whether the temperature detecting means is in contact or non-contact. Is possible.

  According to the fifth aspect of the present invention, the temperature abnormality detecting means can obtain either the high temperature abnormality or the low temperature abnormality of the heating member as well as the same effect as any one of the first to fourth aspects. By detecting either or both of them, the temperature abnormality can be detected finely.

  According to the invention described in claim 6, the same effect as in any one of claims 1 to 5 can be obtained, and the stop signal output means includes a plurality of temperature abnormality signals, a drive instruction signal, Based on the above, the drive signal is calculated by logical operation and output to the drive means, so that the heating means is forcibly stopped, so that the heating means can be driven safely.

  According to the seventh aspect of the invention, it is possible to obtain the same effect as any one of the first to sixth aspects, and the stop signal output means includes a plurality of temperature abnormality signals, a drive instruction signal, The drive signal is logically calculated based on the output and calculated and output to the control means. The control means forcibly stops the operation of the heating means based on the input drive signal or instructs the shut-off means to perform the shut-off operation. Since the control means can recognize how the heating means is driven, the heating means can be monitored from the control means side, and the power supplied from the control means can be monitored. Can be stopped, and the safety of the image forming apparatus can be improved.

  According to the invention described in claim 8, the same effect as in any one of claims 1 to 7 can be obtained, and the stop signal output means outputs an abnormality detection signal based on the temperature abnormality signal. A logical operation is calculated and output to the control means, and the control means is configured to forcibly stop the operation of the heating means based on the input abnormality detection signal or to instruct the shut-off means to perform a shut-off operation. As a result, a temperature abnormality from other than the control unit can be recognized, so that the power supplied from the control unit can be stopped, and the safety of the image forming apparatus can be improved.

  According to the ninth aspect of the invention, it is possible to obtain the same effect as any one of the first to eighth aspects, and the operation of the heating means without using the software such as the control means as the blocking means. In addition to the power cut-off relay that is forcibly stopped, either a thermostat or a thermal fuse or a combination thereof can be used to reliably stop the image forming apparatus without being affected by software runaway. Safety can be improved.

  According to the invention described in claim 10, the same effect as in any one of claims 1 to 9 can be obtained, and a halogen heater, an electromagnetic induction heater, and a carbon heater are used as heating means. It is possible to mount a fixing device.

  According to the eleventh aspect of the present invention, since the notifying means for notifying the operating state of the heating means can be provided, the operating status of the heating means can be easily confirmed, so that an accident during the operation of the heating means is prevented. can do.

  According to the twelfth aspect of the present invention, it is possible to obtain the same effect as that of the first to tenth aspects, as well as the notifying means for notifying the operating state of the heating means, so that the operating status of the heating means can be changed. Since it can confirm easily, the accident during operation | movement of a heating means can be prevented.

  According to the thirteenth aspect of the present invention, the effect similar to that of the eleventh or twelfth aspect can be obtained, and the informing means is provided in the vicinity of the fixing device or inside the fixing device stand, so that the fixing device When performing maintenance or the like, since the operating state of the heating means can be easily confirmed, an accident during the operation of the heating means can be prevented.

  According to the fourteenth aspect of the invention, it is possible to obtain the same effect as that of the eleventh or twelfth aspect, and the notifying means is included in the display unit on which the information related to the image forming apparatus is displayed. Since the operation state of the heating unit can be visually confirmed in the same manner as the function related to image formation, an accident during the operation of the heating unit can be prevented.

  According to the fifteenth aspect of the present invention, the effect similar to that of any one of the eleventh to fourteenth aspects can be obtained, and the notification means is a semiconductor element or a liquid crystal display. Therefore, it is possible to easily confirm the operation state by visual observation, and thus it is possible to prevent an accident during the operation of the heating means.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a schematic configuration diagram of an image forming apparatus 1 according to an embodiment of the present invention.
As shown in FIG. 1, the image forming apparatus 1 includes a photosensitive drum 20, the surface of the photosensitive drum 20 is charged to a predetermined potential by a charger 21, and an image is exposed by an exposure unit 22 to expose the photosensitive drum 20. An electrostatic latent image is formed on the surface, the latent image is developed with a developer (toner) by the developing unit 23 to be visualized as a toner image, and the obtained toner image is transported to the photosensitive drum 20 or the like Is transferred to the recording medium P by the transfer means 24. The photosensitive drum 20 on which the transfer of the toner image has been completed is subjected to the next image formation after removing the remaining toner remaining on the surface by the cleaner 25.

  On the other hand, the recording medium P carrying the toner image is a fixing device (hereinafter referred to as a first fixing device) 10a using an electromagnetic induction heater from the photosensitive drum 20 or a fixing device (hereinafter referred to as a first fixing device) using a halogen heater. 2 is called a fixing device.) Sent to 10b. In the first fixing device 10a or the second fixing device 10b, the unfixed toner image on the recording medium P is fixed, and a print image is obtained on the recording medium P.

  The image forming apparatus 1 of the present invention has a configuration in which the first fixing device 10a and the second fixing device 10b can be selectively mounted according to the use environment or the like.

  The first fixing device 10a includes a heating roller 11a as a heating member, a pressure roller 12a that presses against the heating roller 11a to form a nip portion N, and a first heating unit provided in the heating roller 11a. It comprises a two-induction coil (not shown) and a display lamp 13a as a notification means that lights up during the operation of the first and second induction coils provided in the vicinity of the first fixing device 10a. The toner image on the recording medium P is fixed when passing through the nip N of the pressure contact portion between the heating roller 11a and the pressure roller 12a. The display lamp 13a is preferably a semiconductor element (LED; Light Emitting Diode).

  The second fixing device 10b includes a heating roller 11b as a heating member, a pressure roller 12b that presses against the heating roller 11b to form a nip portion N, and a halogen lamp as a heating unit provided in the heating roller 11b. (Not shown) and a display lamp 13b as a notification means that lights up during operation of a halogen lamp provided in the vicinity of the second fixing device 10b. The toner image on the recording medium P is fixed when passing through the nip N of the pressure contact portion between the heating roller 11b and the pressure roller 12b. The display lamp 13b is preferably a semiconductor element (LED; Light Emitting Diode).

  By providing the display lamps 13a and 13b using LEDs for informing the operating state of the heating means, the operating status of the heating means can be easily confirmed, and by being provided in the vicinity of the fixing device, the fixing device. When performing maintenance or the like, since the operating state of the heating means can be easily confirmed visually, an accident during the operation of the heating means can be prevented.

FIG. 2 shows a schematic control configuration diagram relating to the first fixing device 10a and the second fixing device 10b of the present embodiment.
As shown in FIG. 2, the control configuration of the first fixing device 10a and the second fixing device 10b includes a control unit 100 as a control unit and an abnormality detection circuit unit as a temperature abnormality detection unit mounted on the same substrate. 200 and a stop signal calculation circuit unit 300 as a stop signal output unit, and a power supply stop signal S _off calculated based on various signals from the control unit 100 and the abnormality detection circuit unit 200 serves as a cutoff unit. By operating the circuit unit 50, the power supply to the first fixing device 10a or the second fixing device 10b in the fixing device mount 40 is cut off via an IH (Induction Heating) heater driving unit 400 as a driving unit. It is.

The fixing device mount 40 can mount the IH heater driving unit 400 and the first fixing device 10a or the second fixing device 10b.
The fixing device base 40 outputs a base set signal Ss3 as a base set signal indicating the set state of the fixing device base 40 to the stop signal calculation circuit unit 300. The gantry set signal Ss3 indicates whether the fixing device gantry 40 is set to the image forming apparatus 1, that is, whether the fixing device gantry 40 is set at a predetermined position where image formation is possible and the set lever is at the setting position. In the state where the fixing device base 40 is pulled out to perform maintenance of the first fixing device 10a from the inside of the image forming apparatus 1, there is a possibility that trouble may be caused when image formation is performed.

As the arithmetic logic of the gantry set signal Ss3, when “H”, the fixing device gantry 40 is set to be normal, and when “L”, the fixing device gantry 40 is not set. This is shown as abnormal.
In this embodiment, when the gantry set signal Ss3 is “H”, it indicates that it is normal, and when it is “L”, the logic indicates that it is abnormal, but when it is “H”, it is abnormal. In the case of “L”, the logic indicating normality may be used, and the present invention is not limited to this.

The IH heater driving unit 400 converts AC power input from the commercial power supply AC through the power supply cutoff relay circuit unit 50 into AC current for generating an induction magnetic field in the first and second induction coils, and calculates a stop signal. This is a circuit that supplies drive current to the first and second induction coils based on the first and second drive signals S _fn1 and S _fn2 input from the circuit unit 300. In addition, an identification signal output circuit unit is provided as an identification signal output unit that outputs an identification signal Ss1 indicating whether the IH heater driving unit 400 is present in the power supply path from the commercial power supply AC to the unnecessary signal invalidation circuit unit 230. doing.

  The IH heater driving unit 400 is a driving unit unique to the first fixing device 10a. Accordingly, by detecting whether or not the IH heater driving unit 400 is present, the first fixing device 10a using the IH heater is present if it is present, and the second fixing unit 10a using a halogen lamp if it is not present. Since the fixing device 10b and the fixing device can be identified, the identification device Ss1 can be used to identify the fixing device.

When the operation logic of the identification signal Ss1 is “H”, it indicates that the IH heater driving unit 400 is not present (that is, the mounted fixing device is the second fixing device 10b). "L" indicates that the IH heater driving unit 400 is present (that is, the mounted fixing device is the first fixing device 10a).
In the present embodiment, when the identification signal Ss1 is “H”, the mounted fixing device is the second fixing device 10b, and when it is “L”, the arithmetic logic indicating the first fixing device 10 is used. The logic may indicate that the first fixing device 10a is “H”, and the second fixing device 10b is “L”.

  The first fixing device 10a includes a first induction coil that heats the central portion of the heating roller 11a and a second induction coil that heats an end portion (not shown). Therefore, as a plurality of temperature detecting means for detecting the temperature of the heating roller 11a, a first temperature sensor NC1 for detecting the temperature of the central portion of the heating roller 11a, and a second for detecting the temperature of the image region at the end of the heating roller 11a. A temperature sensor NC2, a third temperature sensor TH3 for detecting the temperature at the center of the heating roller 11a, and a fourth temperature sensor TH4 for detecting the temperature of the non-image area at the end of the heating roller 11a are provided.

  When the first fixing device 10a is mounted, the first to fourth temperature detection signals S1 to S4 as temperature detection signals from the first to fourth temperature sensors NC1, NC2, TH3, and TH4 are included in the abnormality detection circuit unit 200. It is output to the voltage follower 210. Further, the first fixing device 10a outputs a fixing device set signal Ss2 as a fixing set signal indicating a set state with the first fixing device 10a to the stop signal calculation circuit unit 300. The set state of the first fixing device 10a indicates whether the first fixing device 10a is set at a predetermined position of the fixing device mount 40. For example, the maintenance of the first fixing device 10a is performed from the fixing device mount 40. In the state where the first fixing device 10a is pulled out, there is a risk of trouble in image formation.

When the operation logic of the fixing device set signal Ss2 is “H”, it indicates that the first fixing device 10a is set at a predetermined position, which is normal, and when it is “L”, the first fixing device 10a is It shows a state where it is not set at a predetermined position, and this is abnormal.
In the present embodiment, when the fixing device set signal Ss2 is “H”, it indicates that it is normal, and when it is “L”, the logic indicates that it is abnormal, but when it is “H”, It indicates that it is abnormal, and in the case of “L”, it may be a logic indicating that it is normal, and is not limited to this.

  The second fixing device 10b detects, as a plurality of temperature detecting means for detecting the temperature of the heating roller 11b, a fifth temperature sensor TH5 for detecting the temperature of the central portion of the heating roller 11b and the temperature of the end of the heating roller 11b. A sixth temperature sensor TH6 is provided.

When the second fixing device 10b is mounted, temperature detection signals from the fifth and sixth temperature sensors TH5 and TH6 are output to the voltage follower 210 in the abnormality detection circuit unit 200. Further, the second fixing device 10 b outputs a fixing device set signal (not shown) indicating the set state of the second fixing device 10 b to the stop signal calculation circuit unit 300.
Since the fixing device set signal from the second fixing device 10b is a signal having the same operation logic as that of the first fixing signal 10a, illustration and description thereof are omitted.

  The first to sixth temperature sensors as temperature detecting means are installed in non-contact or contact with the outer peripheral side of the heating roller. For example, a temperature sensor such as a thermistor, a thermocouple, an infrared sensor, or the like can be used. Anything can be used as long as it can detect the temperature of the heating roller or the temperature in the vicinity of the heating roller.

  The number of temperature sensors provided in the first fixing device 10a and the second fixing device 10b, which employs an electromagnetic induction heater and a halogen heater as the heating means, varies depending on the heating method, so that the heating method varies depending on the heating method. Since the temperature of the roller can be detected appropriately, the power supply can be quickly stopped in response to a temperature abnormality peculiar to each heating method.

  Hereinafter, the case where the first fixing device 10a is mounted as the fixing device of the image forming apparatus 1 will be described.

The control unit 100 comprehensively controls the first and second fixing devices 10a and 10b, and performs centralized control of the operation of each unit of the image forming apparatus 1.
Further, based on the first to fourth temperature detection signals S1 to S4 input from the voltage follower 210, a temperature abnormality signal Se indicating a temperature abnormality of the heating roller 11a and an instruction for ON / OFF control of the first induction coil are provided. A first drive instruction signal S _fn1-I as a drive instruction signal to be performed and a second drive instruction signal S _fn2-I as a drive instruction signal for instructing ON / OFF control of the second induction coil are generated and stopped The signal is output to the signal arithmetic circuit unit 300.

As the operation logic of the temperature abnormality signal Se, “H” indicates that it is normal, and “L” indicates that it is abnormal.
In this embodiment, when the temperature abnormality signal Se is “H”, it indicates that the temperature is normal, and when it is “L”, the logic indicates that it is abnormal. In the case of “L”, the logic indicating normality may be used, and the present invention is not limited to this.

As the arithmetic logic of the first drive instruction signal S _fn1-I , “H” indicates that energization to the first induction coil is stopped (OFF), and “L” indicates that the first induction coil is not supplied to the first induction coil. Indicates that energization is not stopped (ON).
In the present embodiment, when the first drive instruction signal S _fn1-I is “H”, it indicates that it is OFF, and when it is “L”, the logic indicates that it is ON, but “H”. In the case of “L”, the logic may indicate ON, and in the case of “L”, the logic may indicate OFF.
Since the operation logic of the second drive instruction signal S _{fn2-I is the same as} the operation logic of the first drive instruction signal S _fn1-I , description thereof is omitted.

Furthermore, a first drive signal S _fn1 and a second drive signal S _fn2 as drive signals from a stop signal calculation circuit unit 300, which will be described later, and a first abnormality detection signal S _NC and a second abnormality detection signal S _{TH as} abnormality detection signals. The first display signal S _LED1 and the second display signal S _LED2 are input.
When the first drive signal S _fn1 and the second drive signal S _fn2 are input, the control unit 100 recognizes how the first and second induction coils are driven. When the first abnormality detection signal _SNC and the second abnormality detection signal _STH are input, the fixing device based on a plurality of temperature abnormality signals, which will be described later, separate from the temperature abnormality signal Se detected in the control unit 100. Recognize abnormalities. When the first display signal S _LED1 and the second display signal S _LED2 are input, the display lamp 13a or the display lamp 13b is turned on or off based on the first display signal S _LED1 and the second display signal S _LED2 .

  The control unit 100 may be a control unit unique to the first fixing device 10a and the second fixing device 10b, and is connected to each unit in the image forming apparatus 1 so as to be able to transmit and receive various types of information to and from each other. It is also possible to receive information from each part, judge the received information, output information such as an operation instruction as a judgment result to each part, and be included in a control unit that supervises each part.

  The abnormality detection circuit unit 200 includes a voltage follower 210, a high / low temperature detection comparator circuit unit 220, and an unnecessary signal invalidation circuit unit 230.

  The voltage follower 210 receives a temperature detection signal input from the selected temperature detection signal (in FIG. 2, the first to fourth temperature detection signals S1 to S4 input from the first fixing device 10a). The accuracy is increased and output to the control unit 100 and the high / low temperature detection comparator circuit unit 200.

  The high-temperature / low-temperature detection comparator circuit unit 200 is based on the temperature detection signals (first to fourth temperature detection signals S1 to S4 in FIG. 2) input from the voltage follower 210, and is used as a plurality of temperature abnormality signals. And a low temperature abnormality signal are calculated.

For example, when the thermistor is used as the first to fourth temperature sensors NC1, NC2, TH3, and TH4, the values of the first to fourth temperature detection signals S1 to S4 are the resistance values of the thermistors. The temperature is confirmed by monitoring the change as voltage. By using a comparator to determine whether the voltage is higher or lower than a predetermined voltage value (threshold value), the high / low temperature can be detected. When the first to fourth temperature sensors NC1, NC2, TH3, and TH4 are disconnected, the resistance value of the thermistor becomes infinite (open state), and becomes zero when short-circuited (short state).
Therefore, the high temperature abnormality signal is to detect the case where the temperature detected from the first to fourth temperature sensors NC1, NC2, TH3, TH4 is higher than a predetermined temperature, or one or both of the cases where the short circuit occurs. Can do. The low temperature abnormality signal can detect either one or both of the case where the temperature detected from the first to fourth temperature sensors NC1, NC2, TH3, TH4 is lower than the predetermined temperature, or the case where the wire is disconnected.

As a plurality of abnormal signals calculated from the high temperature / low temperature detection comparator circuit unit 200 and the operation logic of the abnormal signals,
S11: High temperature abnormality signal based on the signal from the first temperature sensor NC1 H: Normal L: Abnormality S12: 低温 Low temperature abnormality signal H: Normal L: Abnormality S21: High temperature abnormality signal based on the signal from the second temperature sensor NC2 H: Normal L: Abnormal S22: 低温 Low temperature abnormal signal H: Normal L: Abnormal S31: High temperature abnormal signal based on the signal from the third temperature sensor TH3 Normal: L: Abnormal S32: 低温 Low temperature abnormal signal H: Normal L: Abnormal S41 : High temperature abnormality signal based on signal from fourth temperature sensor TH4 H: Normal L: Abnormal S42: 〃 Low temperature abnormality signal H: Normal L: Abnormal. When each temperature abnormality signal is “H”, it indicates that the temperature is normal, and when it is “L”, the logic indicates that the temperature is abnormal.

  In this embodiment, when the temperature abnormality signal is “H”, it indicates that the temperature is normal, and when it is “L”, the logic indicates that it is abnormal, but when it is “H”, it is abnormal. If it is “L”, it may be a logic indicating that it is normal, and it may not be limited to this.

  By calculating one or both of the high temperature abnormality signal and the low temperature abnormality signal at the center and end of the heating roller, the temperature distribution abnormality in the axial direction of the heating roller can be finely detected.

The unnecessary signal invalidation circuit unit 230 includes a plurality of temperature abnormality signals S11, S12, S21, S22, S31, S32, S41, S42 input from the high temperature / low temperature detection comparator circuit unit 220 and the IH heater driving unit 400. Based on the identification signal Ss1, an unnecessary signal that is arithmetically processed in the stop signal arithmetic circuit unit 300 is invalidated.
The abnormal temperature signals S11, S12, S21, S22, S31, S32, S41, and S42 processed in the unnecessary signal invalidation circuit unit 230 are output to the stop signal calculation circuit unit 300.

The stop signal calculation circuit unit 300 receives a plurality of temperature abnormality signals S11, S12, S21, S22, S31, S32, S41, and S42 input from the unnecessary signal invalidation circuit unit 230 and the first fixing device 10a. a fixing device set signal Ss2, the pedestal set signal Ss3 inputted from the fixing device frame 40, on the basis of the temperature anomaly signal Se is input from the control unit 100 calculates a power supply stop signal S _off as a stop signal, The power is output to the power cutoff relay circuit unit 50.

Also, a plurality of temperature abnormality signals S11, S12, S21, S22, S31, S32, S41, and S42 input from the unnecessary signal invalidation circuit unit 230, and a fixing device set signal Ss2 input from the first fixing device 10a. Based on the gantry set signal Ss3 input from the fixing device gantry 40, the temperature abnormality signal Se input from the control unit 100, and the first and second drive instruction signals S _fn1-I , S _fn2-I , The first and second drive signals S _fn1 and S _fn2 for turning on and off the first and second induction coils and the first and second display signals S _LED1 and S _LED2 are calculated and output to the IH heater driving unit 400.

As the arithmetic logic of the signal output from the stop signal arithmetic circuit unit 300,
S _off : Power supply stop signal H: OFF L: ON
“H”: Operates the power cut-off relay circuit unit 50 to cut off the supplied power.
“L”: _Power supply interruption relay circuit unit 50 is not operated S _fn1 : First drive signal H: OFF L: ON
“H”: Stops energization of the first induction coil
“L”: Energizing the first induction coil S _fn2 : Second drive signal H: OFF L: ON
“H”: Stops energization of the first induction coil
"L": S _NC energize the first induction coil: first abnormality detection signal H: abnormal L: Normal S _TH: second abnormality detection signal H: abnormal L: Normal S _LED1: first display signal H: lighting L : Off S _LED2 : Second display signal H: On L: Turn off.

  In this embodiment, when each signal is “H”, it indicates that the signal is OFF, abnormal, or lit, and when it is “L”, the logic indicates that the signal is ON, normal, or extinguished. , “H” may indicate ON, normal, and extinguished respectively, and “L” may indicate logic indicating OFF, abnormal, and lit, respectively, and may not be limited to this. .

The power supply cut-off relay circuit unit 50 cuts off AC power from the commercial power supply AC based on the power supply stop signal S _off from the stop signal calculation circuit unit 300.
In this embodiment, the power supply to the heating means is cut off using the power cut-off relay. However, either a thermostat or a thermal fuse or a combination of them may be added, and power feed is stopped. This is not a limitation as long as the power supply to the heating means is cut _off based on the signal _Soff .

FIG. 3 shows a circuit configuration example of the unnecessary signal invalidation circuit unit 230 and a circuit configuration example of the stop signal calculation circuit unit 300.
First, a circuit configuration example of the unnecessary signal invalidation circuit unit 230 will be described.

  In the present embodiment, a plurality of temperature abnormality signals S11 and S12 based on the first to fourth temperature detection signals S1 to S4 from the first to fourth temperature sensors NC1, NC2, TH3, and TH4 provided in the first fixing device 10a. , S21, S22, S31, S32, S41, and S42 are calculated. On the other hand, it is assumed that four temperature abnormality signals are calculated based on the temperature detection signals from the fifth and sixth temperature sensors TH5 and TH6 provided in the second fixing device 10b.

Since the stop signal calculation circuit unit 300 calculates the power supply stop signal S _off based on a plurality of temperature abnormality signals, the input terminals A1, A2, B1, B2, C1, C2, D1, and D2 (eight here).
However, when there is no conventional unnecessary signal invalidation circuit unit 230, when the second fixing device 10b is selected, four temperature abnormal signals are input, so the four unnecessary terminals are connected. Since the sensor to be used does not exist and becomes an open end, the arithmetic logic is not fixed and there is a risk of adverse effects.

  Therefore, in the present invention, an unnecessary signal invalidation circuit unit 230 that invalidates an unnecessary signal according to the selected fixing device is provided.

  Of the input terminals A1, A2, B1, B2, C1, C2, D1, and D2 of the stop signal arithmetic circuit unit 300, the input terminals A1, A2, C1, and C2 are shared with the first fixing device 10a and the second fixing device 10b. The input terminals B1, B2, D1, and D2 are set to use only the first fixing device 10a. Therefore, the input terminals B1, B2, D1, and D2 need to be disabled no matter what signals are input when the second fixing device 10b is selected.

  In order to invalidate the signals input to the input terminals B1, B2, D1, and D2, the signals are input when the second fixing device 10b is mounted based on the identification signal Ss1 and the input signal. It is configured to always output normal logic regardless of the signal.

In the unnecessary signal invalid circuit portion of FIG. 3, an OR circuit is used to perform an OR operation between the identification signal Ss1 and the input signal on the input side of the OR circuit, and when the first fixing device 10a is mounted, On the input side of the circuit, the logical sum of the identification signal Ss1 and the temperature abnormality signals S21, S22, S41, and S42 is obtained, the signals of the temperature abnormality signals S21, S22, S41, and S42 are validated, and the second fixing device 10b is mounted. In this case, the normal logic is always output regardless of the input signal.
Note that an AND circuit or a NOT circuit may be used, and this is not a limitation as long as unnecessary signals can be invalidated.

A circuit configuration example of the stop signal arithmetic circuit unit 300 will be described.
First, the stop signal arithmetic circuit unit 300 uses a plurality of temperature abnormality signals S11, S12, S21, S22, S31, S32, S41, and S42 input from the unnecessary signal invalid circuit unit 230 by using an AND circuit. The abnormal signals are aggregated as the calculation signal Z1 and the aggregated signals are calculated as the first abnormality detection signal S _NC and the second abnormality signal S _TH for each type of temperature sensor, and are output to the control unit 100.

  In addition, as another example of a method of collecting a plurality of temperature abnormality signals, it may be arranged for each coil arrangement (central part, end part) or the like. An abnormality detection signal may be output to the control unit 100.

A plurality of abnormality detection signals S _NC , S _TH are calculated based on the plurality of temperature abnormality signals S 11, S 12, S 21, S 22, S 31, S 32, S 41, S 42 and output to the control unit 100. Therefore, the power supply from the control unit 100 can be stopped and the safety of the image forming apparatus 1 can be improved.

Next, an operation signal Z1 of the plurality of temperature abnormality signal, the fixing device set signal Ss2, the pedestal set signal Ss3, and a temperature abnormality signal Se to the arithmetic processing to calculate a power supply stop signal S _off, power supply cutoff relay circuit To the unit 50.

  By using the fixing device set signal Ss2, the gantry set signal Ss3, and the input signal, the first fixing device 10a or the second fixing device 10b is mounted on the image forming apparatus 1 at a predetermined position where an image can be reliably formed. Only in this case, the heating means can be driven, so that the safety of the image forming apparatus 1 can be improved.

  By using the temperature abnormality signal Se as an input signal, it is possible to detect a temperature abnormality from the control unit 100 and to determine an abnormality of the first fixing device 10a or the second fixing device 10b from a different side surface. The safety of the forming apparatus 1 can be improved.

Further, a calculation signal Z4 obtained by calculating a plurality of temperature abnormality signal calculation signals Z1, a fixing device set signal Ss2, a gantry set signal Ss3, and a temperature abnormality signal Se, and first and second drive instruction signals _Sfn1-I. , _Sfn2-I are calculated to calculate the first and second drive signals S _fn1 and S _fn2 and the display signals S _LED1 and S _LED2, and the first and second drive signals S _fn1 and S _fn2 are driven by the IH heater. The first and second display signals S _LED1 and S _LED2 are output to the control unit 100.

An operation signal Z1 of the plurality of temperature abnormality signal, the fixing device set signal Ss2, the based and frame set signal Ss3, the operation signal Z4 that processing the temperature error signal Se (i.e., power supply stop signal S _off) 1 By calculating the drive signal S _fn1 and the second drive signal S _fn2 and outputting them to the IH heater drive unit 400, the first and second induction coils can be safely turned on / off.

By _outputting the calculated first drive signal S _fn1 and second drive signal S _fn2 to the control unit 100, the control unit 100 can recognize how the heating means is driven. The heating unit can also be monitored from the unit 100 side, and the supply power can be stopped from the control unit 100, and the safety of the image forming apparatus 1 can be improved.

  The circuit configuration example of the stop signal arithmetic circuit unit 300 in FIG. 3 is configured to perform arithmetic processing on each signal by taking a logical product using an AND circuit, but is configured using an OR circuit, a NOT circuit, or the like. This is not a limitation.

In this embodiment, the identification signal Ss1 when the first fixing device 10a using the electromagnetic induction heater and the second fixing device 10b using the halogen heater can be mounted is “H”, “ The fixing device is identified using a 1-bit signal of “L” (that is, “1”, “0”). However, in the case of using a third fixing device using a carbon heater, a 2-bit identifying signal is used. Can be identified by providing an identification signal output circuit for outputting. A plurality of fixing devices can be further identified by using an identification signal having the number of bits corresponding to the number of fixing devices to be identified.
In this case, the unnecessary signal invalidation circuit unit 230 can be realized by, for example, combining OR circuits in multiple stages.

  In the present embodiment, the pedestal set signal Ss3 and the fixing device set signal Ss2 have been described. However, either the failure signal indicating the temperature sensor failure state or the connection state detection signal indicating the connection state of the driving circuit of the fixing device. Or a combination thereof may be used.

  In the present embodiment, the display lamps 13a and 13b are used as notification means. However, the display screen of the display unit configured by a liquid crystal display such as an LCD (Liquid Crystal Display) that displays information related to the image forming apparatus 1 is described. It may be notified above, and may be a CRT (Cathode Ray Tube) display, a PDP (Plasma Display Panel) display, or an EL (Electro Luminescence) display, etc., and the operating state of the induction coil according to an instruction signal input from the control unit 100 Can be confirmed by visual observation of the operation status of the heating means in the same manner as the function related to image formation, so that an accident during the operation of the heating means can be prevented. Not necessarily.

In this way, logical operation is performed based on the plurality of temperature abnormality signals S11, S12, S21, S22, S31, S32, S41, and S42, the fixing device set signal Ss2, the gantry set signal Ss3, and the temperature abnormality signal Se. The power supplied to the first and second induction coils is cut _off based on the calculated power supply stop signal Soff, so that the first fixing device 10a can be surely operated regardless of the control runaway of the control unit 100. Therefore, the safety of the image forming apparatus 1 can be improved.
Then, based on the identification signal Ss1, by providing an unnecessary signal invalidating circuit unit 230 to disable unnecessary abnormal temperature signal to calculate the power supply stop signal S _off make a decision instruction of the forced stop, the first fixing device 10a Since the image forming apparatus 1 that can drive the second fixing device 10b and the second fixing device 10b with the same circuit can be realized, it is not necessary to configure a drive circuit or a peripheral circuit for each heating unit, and the number of components to be managed is reduced. The cost can be expected to decrease, and the versatility of the image forming apparatus 1 can be improved.

  In addition, since the operation of the heating unit is forcibly stopped without using the control unit 100, the operation can be stopped without being affected by software runaway, and the safety of the image forming apparatus 1 can be improved. .

1 is a schematic configuration diagram of an image forming apparatus 1 in an embodiment of the present invention. FIG. 3 is a schematic control configuration diagram relating to first and second fixing devices 10a and 10b. 2 is a circuit configuration example of an unnecessary signal invalidation circuit unit 230 and a circuit configuration example of a stop signal calculation circuit unit 300.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10a 1st fixing apparatus 10b 2nd fixing apparatus 11a, 11b Heating roller 12a, 12b Pressure roller 13a Display lamp 100 Control part 20 Photosensitive drum 21 Charger 22 Exposure means 23 Developer 24 Transfer means 25 Cleaner 200 Abnormality Detection circuit unit 210 Voltage follower 220 High temperature / low temperature detection comparator circuit unit 230 Unnecessary signal invalidation circuit unit 300 Stop signal calculation circuit unit 40 Fixing device mount 400 IH heater driving unit 50 Power supply cutoff relay circuit unit A1, A2, B1, B2, C1, C2, D1, D2 Input terminal AC Commercial power supply N Nip portion P Recording medium S1, S2, S3, S4 First to fourth temperature detection signals S11, S12, S21, S22, S31, S32, S41, S42 Temperature abnormal signal Se temperature abnormal signal S _fn1 , S _fn2 first and second drive signals S _fn1-I , S _{f n2-I} the first and second drive instruction signal S _LED1, S _LED2 first and second display signal S _NC first abnormality detection signal S _TH second abnormality detection signal S _off power supply stop signal Ss1 identification signal Ss2 fixing device set signal Ss3 trestle Set signal

Claims (15)

A plurality of fixing devices having different heating means can be selectively mounted, a temperature detecting means for detecting temperatures at a plurality of detection positions of the heating member in the mounted fixing device, and a plurality of detected temperature detection signals Based on the temperature abnormality detection means for detecting temperature abnormality at each detection position based on the above, and a drive instruction signal for controlling the on-off control of the heating means by performing overall control of the mounted fixing device And a control means for detecting a temperature abnormality based on a plurality of temperature detection signals, a shut-off means for cutting off the power supply to the heating means, and the plurality of temperature abnormality signals detected based on the drive instruction signal. An image forming apparatus comprising: a stop signal output unit that forcibly stops the operation of the heating unit or outputs a stop signal that instructs the blocking unit to perform a blocking operation;
An identification signal output means for outputting an identification signal for identifying the mounted fixing device;
Unnecessary signal invalidating means for invalidating an abnormal temperature signal unnecessary for determination of forced stop of the heating means based on the identification signal according to the mounted fixing device;
An image forming apparatus. The image forming apparatus according to claim 1.
In addition to the plurality of temperature abnormality signals, the stop signal output means includes a gantry set signal that indicates a set state of the gantry of the fixing device, a fixing set signal that indicates a set state of the fixing device, and a failure state of the temperature detection means A failure detection signal indicating a connection detection signal indicating a connection state of a driving circuit of the fixing device or a combination thereof, and making a determination as an input,
An image forming apparatus. The image forming apparatus according to claim 1, wherein
The temperature detection means is installed at the position of the axially central portion or end portion of the heating member or a combination thereof,
An image forming apparatus. The image forming apparatus according to any one of claims 1 to 3,
The temperature detecting means is configured by either a sensor that contacts the heating member, a non-contact sensor, or a combination thereof;
An image forming apparatus. In the image forming apparatus according to any one of claims 1 to 4,
The temperature abnormality detection means detects that the temperature abnormality of the heating member is either a high temperature abnormality or a low temperature abnormality or both,
An image forming apparatus. In the image forming apparatus according to any one of claims 1 to 5,
The stop signal output means calculates a drive signal for turning on / off the heating means based on the plurality of temperature abnormality signals and the drive instruction signal, and calculates the drive signal for driving the heating means. It was configured to forcibly stop the heating means by outputting,
An image forming apparatus. The image forming apparatus according to any one of claims 1 to 6,
The stop signal output means calculates a drive signal for turning ON / OFF the heating means based on the plurality of temperature abnormality signals and the drive instruction signal, and outputs the calculated drive signal to the control means. Is configured to forcibly stop the operation of the heating means based on the input drive signal or to instruct the interruption means to perform the interruption operation,
An image forming apparatus. The image forming apparatus according to any one of claims 1 to 7,
The stop signal output means calculates and outputs an abnormality detection signal based on the plurality of temperature abnormality signals, and outputs the abnormality detection signal to the control means. The control means That the operation is forcibly stopped or the interruption means is instructed to perform the interruption operation;
An image forming apparatus. The image forming apparatus according to any one of claims 1 to 8,
In addition to the power supply interruption relay provided in the power supply path to the heating means, the interruption means includes either a thermostat or a thermal fuse or a combination thereof,
An image forming apparatus. The image forming apparatus according to any one of claims 1 to 9,
The heating means is a halogen heater, an electromagnetic induction heater or a carbon heater;
An image forming apparatus. In an image forming apparatus including a fixing device having a driving unit that receives power supplied from a power source and drives a heating unit, and a heating member that is heated by the heating unit.
Comprising an informing means for informing the operating state of the heating means;
An image forming apparatus. The image forming apparatus according to any one of claims 1 to 10,
Comprising an informing means for informing the operating state of the heating means;
An image forming apparatus. The image forming apparatus according to claim 11 or 12,
The notification means is provided in the vicinity of the fixing device or in the fixing device mount;
An image forming apparatus. The image forming apparatus according to claim 11 or 12,
The notification means is included in a display unit on which information about the image forming apparatus is displayed;
An image forming apparatus. The image forming apparatus according to any one of claims 11 to 14,
The informing means is any one of a semiconductor element (LED; Light Emitting Diode) or a liquid crystal display (LCD) that emits light when a current is passed, or a combination thereof.
An image forming apparatus.

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