JP4476587B2 - Image forming apparatus and heating source control method in image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as an electrophotographic copying apparatus, for example, a printer, a color printer, a copying machine, a color copying machine, a printing apparatus having a combined function by an extended function, and in particular, a heating source for dehumidification and dew condensation prevention. The present invention relates to an image forming apparatus provided.

  In an image forming apparatus such as a copying machine, when there is a temperature difference between the temperature of the machine parts in each part and the temperature of the usage environment, especially in the early morning in cold weather, the machine parts cause condensation and the following Problems arise. If the lens or mirror of the optical system is condensed, no image is taken. In addition, when the charged mechanical parts and the photosensitive drum are condensed, the image may not be captured, blurred, or thinned, and a paper jam may occur. In addition, condensation of the mechanical parts of the paper feed system and moisture absorption of the transfer paper cause problems such as paper jams, poor transfer of the transfer paper, or adverse effects on the image quality of the transfer paper.

  Therefore, conventionally, in order to prevent such harmful effects caused by condensation, a heater for warming each machine part of the copying machine is arranged in each part of the apparatus so that the heater is operated at night when the apparatus is not used. . In general, the wattage (capacity) of this heater is determined so that the temperature becomes an appropriate temperature after saturation. Various control methods have been proposed for controlling these so-called dehumidifying heaters or dew condensation prevention heaters.

  For example, the prior art described in Patent Document 1 will be described with reference to FIG. FIG. 10 is a schematic circuit diagram showing a power supply circuit of the copying machine. First, when using a copying machine, the power switch 66 is turned ON. As a result, the power switch 66 is switched to the side opposite to the position shown in FIG. Therefore, power is supplied to the control circuit 69 and the AC load 68, and the copying machine can be used.

  When the use of the copying machine is stopped, the power switch 66 is turned off. Thereby, the power switch 66 is switched to the position shown in FIG. In this state, by closing the make contact 65a and the make contact 65b of the timer 65, power can be supplied to the heaters 51, 52, and 53.

  That is, the power supply circuit described in Patent Document 1 has a circuit configuration in which the dehumidification or dew condensation prevention heater operates only when the apparatus is not used and the power switch 66 is OFF.

  Therefore, in an image forming apparatus having a power supply circuit described in Patent Document 1, a so-called energy saving mode (a heater for controlling the temperature of a fixing device that fixes a transferred toner image when copying is not performed with the power switch 66 turned on) Is turned off.) Sometimes the heater for dehumidification or condensation prevention cannot be operated.

  Therefore, depending on the operating environment of the device, the temperature and humidity around the fuser in the energy saving mode may be inappropriate for copying, and when starting copying from the energy saving mode, paper jams or transfer paper transport There is a problem that a defect or a transfer sheet image defect occurs.

  Next, the prior art described in Patent Document 2 will be described with reference to FIG. FIG. 11 is a schematic circuit diagram showing the heater control unit of the copying machine. First, when the copying machine main body is connected to a commercial power supply (100 V), power is supplied to the AC control unit 11. Then, the AC control unit 11 turns on the dehumidifying heater 15 via the switching contact relay 111.

  Subsequently, when the AC control unit 11 turns on the switch 16, power is supplied to the DC power source 12 and the DC power source 12 is activated. In the DC power supply 12, AC100V is converted into DC5V and DC24V. The converted electric power is supplied to the controller unit 13, the controller unit 13 is activated, and the copying machine is activated. And the controller part 13 sends a control signal to the switching contact relay 111, and switches a relay contact. By this switching, the dehumidifying heater 15 is switched from the ON state to the OFF state.

  Therefore, in this heater control unit, the ON / OFF operation of the dehumidifying heater 15 is performed using the second contact in the switching contact relay 111. Accordingly, the dehumidifying heater 15 cannot be energized when the main power switch 16 of the copying machine is turned on, the copying machine is activated, and the temperature of the fixing device 14 is controlled. Therefore, depending on the use environment of the copying machine, there is a problem that paper jam, transfer paper transfer failure, or transfer paper image failure occurs.

Further, the conventional techniques described in Patent Documents 3 and 4 disclose a method of controlling energization according to the temperature of the fixing device in controlling the dehumidifying heater or the dew condensation prevention heater. Moreover, in the prior art described in Patent Document 5, a method of controlling energization to the dehumidifying heater by a controlled relay is disclosed. However, the power supply circuit of the copying machine to which these conventional techniques are applied, like the power supply circuits described in Patent Documents 1 and 2, cannot control the CPU when the main power switch is turned off. There is a problem that energization to the heater cannot be controlled.
JP-A-9-269706 Japanese Patent Laid-Open No. 10-319796 JP-A-8-225169 Japanese Patent Laid-Open No. 11-272149 JP 2002-215006 A

  Incidentally, in recent image forming apparatuses such as copying machines, there is an increasing demand for not only high image quality but also high speed. Therefore, when the fixing device is moved from the cold state to the operable state, it is general to supply most of the electric power of the copying machine to the fixing device heater in order to shorten the rise time. That is, the remaining power, excluding the power consumed by the DC power supply or the like that is minimum required for machine operation, is allocated to the power consumption of the fixing device heater. However, when the dehumidification or dew condensation prevention heater is energized for the purpose of high image quality during the rise time of the device, the power consumption is not supplied to the heater for the fixing device, so it is difficult to shorten the rise time. There is a problem.

  Also, when energizing the dehumidification or dew condensation prevention heater for the purpose of high image quality while ensuring the power consumption of the fixing unit heater to shorten the rise time of the device, the consumption due to the dehumidification or dew condensation prevention heater energization Since power is added, the power consumption during the operation of the copying machine reaches its peak, which may exceed the rated power of the household commercial power supply.

  In addition, the tendency to further promote energy saving has become prominent due to environmental considerations. Therefore, in an image processing apparatus such as a copying machine, when the apparatus is not used, it is an essential requirement not only to turn off the heater of the fixing unit but also to turn off the power source for driving the addition of a motor, a clutch, a solenoid and the like. It has become to. Furthermore, when the standard that defines power saving (ex. Energy Star: varies depending on the device, for example, the device is not operating (power consumption 15W or less in the energy saving mode) is not accepted in the market. Because there is a problem.

  Accordingly, in view of the above-described problems, the present invention enables a plurality of dehumidification or dew condensation prevention heaters provided at each part in the apparatus to be always operable in an image forming apparatus such as a copying machine. An object of the present invention is to provide an image forming apparatus that prevents clogging, transfer paper transfer failure, image failure, and the like.

  Another object of the present invention is to provide an image forming apparatus in which the power consumption of the apparatus is adjusted within the rated power range of the household commercial power supply by adjusting the power distribution of each part of the apparatus according to the control according to the operation state of the apparatus. And

  Further, to provide an image forming apparatus in which the power consumption of the apparatus in the energy saving mode satisfies the international energy star standard value by adjusting the power distribution of each part of the apparatus by control according to the operation state of the apparatus. With the goal.

  It is another object of the present invention to provide an image forming apparatus that realizes shortening of the startup time of the apparatus by adjusting the power distribution of each part of the apparatus by control according to the operation state of the apparatus.

The invention of claim 1, wherein the fixing you closed and the heating source connection detecting means for detecting a connection state of the first heat source for heat insulating the predetermined portion of the images forming apparatus, a heating member and a second heat source possess a vessel, and a control means for DUTY controlling the power supply to the fixing device, said first heating source, regardless of the power oN / OFF of the image forming apparatus, for supplying power to the apparatus main body When the connection of the first heating source is detected by the heating source connection detecting means, the control means can connect the first power source according to the power consumption of the first heating source. as the first heat source and the total power consumption of the fixing unit is below the power available from the AC power source, characterized in that to change the energization DUTY to the fixing device.

The invention according to claim 2 has a break contact type relay circuit for supplying power to a third heating source, and the power ON is at least a first mode capable of printing and energy saving. the there is a mode, the relay circuit, the off when the printable first mode, according to claim 1, wherein that you turn on when the second mode of realization of the energy savings Image forming apparatus .

According to a third aspect of the invention, fixing you closed and the heating source connection detecting means for detecting a connection state of the first heat source for heat insulating the predetermined portion of the images forming apparatus, a heating member and a second heat source vessels and the energization of the fixing device a heating source control method for an image forming apparatus having a control means for DUTY control, wherein the first heating source, the image forming apparatus power ON / Regardless of being OFF, it can be connected to an AC power source that supplies power to the apparatus main body, and when the control means detects the connection of the first heating source by the heating source connection detection means, the first A step of changing energization DUTY to the fixing device so that the total power consumption of the first heating source and the fixing device is equal to or lower than the power that can be used from the AC power source according to the power consumption of the heating source. It is characterized by having .

According to a fourth aspect of the present invention, in the image forming apparatus according to the first or second aspect, there are a plurality of the first heating sources, and the heating source connection detecting means is provided for each of the first heating sources. And

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first, second, and fourth aspects, the fixing device includes a fixing temperature detecting unit that detects temperature information of the heating member, the start when the power oN of the image forming apparatus, and a DC power unit circuit for generating a DC voltage, to the fixing device reaches a fixable temperature, or until a predetermined time after reaching the fixing temperature, the DC stopping the power supply to the load of the drive system is powered by the power supply unit circuit, and the power has been supplied to the load of the drive system, the power supply control means for supplying and adding to the fixing device, the Yes, characterized in that.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the second heating source is two heaters, and at the same time as or after the fixing device reaches a fixing possible temperature. , the two heaters are allowed to simultaneously lit, characterized in that it have a current supply control means for controlling so as to be turned on alternately.

According to a seventh aspect of the present invention, in the image forming apparatus according to the third aspect, there are a plurality of the first heating sources, and the heating source connection detecting means is provided for each of the first heating sources. To do.

The invention according to claim 8 is the heating source control method according to claim 3 or 7, wherein the fixing device has fixing temperature detecting means for detecting temperature information of the heating member, and the fixing device can be fixed. To the load of the drive system supplied with power by the DC power supply circuit that is activated when the power supply of the image forming apparatus is turned on until the temperature is reached or until a predetermined time after reaching the fixable temperature. And stopping the power supply and adding the power supplied to the load of the drive system to the fixing device .

According to a ninth aspect of the present invention, in the heating source control method according to the eighth aspect, the second heating source is two heaters, and the fixing device reaches a fixable temperature or at a predetermined time thereafter. And the step of controlling the two heaters that have been turned on simultaneously to be turned on alternately.

  According to the present invention, it is possible to always supply power to a necessary part to a heater for dehumidification or dew condensation prevention. Therefore, good image quality and conveyance quality can be maintained. Further, by detecting the connection of the optional dehumidifying or dew condensation preventing heater, the heater energization duty of the fixing device can be changed and the operation can be performed without exceeding the rated power of the commercial power source. Further, the rise time can be shortened in the machine not equipped with the option, compared with the machine equipped. In addition, in a simple system in which the option is not installed, not only the rise time but also the rise time from the power saving mode can be shortened as compared with the installed machine. Therefore, it is possible to obtain a standard such as an energy star.

  According to the present invention, an improvement in the power supply circuit makes it possible to always supply power to a heater for dehumidification or dew condensation prevention at a required portion, and thus an image forming apparatus that realizes good image quality and conveyance quality is provided. be able to. Further, by detecting the connection of the optional dehumidifying or dew condensation preventing heater, the heater energization duty of the fixing device can be changed to provide an image forming apparatus that operates without exceeding the rated power of the commercial power supply. In addition, an image forming apparatus that realizes a shortened rise time can be provided for a machine not equipped with an option, as compared to a machine with an option. In addition, a simple system with no options installed can not only shorten the rise time but also reduce the rise time from the power saving mode compared to the installed machine, and an image forming device that meets the standards such as Energy Star. Can be provided.

  An embodiment of the present invention will be described with reference to the accompanying drawings by taking a color copying machine as an example. However, this embodiment is also applied to other image forming apparatuses such as a monochrome copying machine.

  FIG. 8 is a schematic external view of a color copying machine according to an embodiment of the present invention. As shown in FIG. 8, the color copying machine includes a copying machine main body 41, an automatic document feeder [ADF] 42, a finisher 43 with staples and a shift tray, a duplex printing unit 44, an extended sheet feeding tray 45, and a one-bin sheet discharge. It comprises a tray 46 and a manual feed unit 47.

  FIG. 9 is a schematic configuration diagram of an engine of a color copying machine according to an embodiment of the present invention. As shown in FIG. 9, the color copier engine houses and conveys a scanner unit for reading a document, an electrophotographic process unit for forming a toner image, a fixing unit for fixing a toner image, and transfer paper. The sheet feeding unit is composed of a writing unit for forming a latent image of image data on the photosensitive member.

  A scanner 84 for reading the original is provided with a lamp 84 for illuminating the original. The reflected light of the original by the lamp is imaged on the CCD 87 via the mirror 85, the lens 86, etc., and converted into an electrical signal as image data. The electrophotographic process unit is a part that forms a toner image and transfers the toner image onto a sheet. A process device is provided around the photoreceptor. That is, around the photosensitive member 1, there are a charging unit 2, a magenta developing unit 3M, a cyan developing unit 3C, a yellow developing unit 3Y, a color developing unit group 3 including a black developing unit 3K, a photosensitive unit cleaning device 4, and a static elimination lamp 5. Are arranged in this order. A belt-like intermediate transfer member 6 is disposed between the color developing device group 3 and the photoconductor cleaning device 4 so as to face each other. A temporary transfer unit 7 is disposed inside the intermediate transfer member. A secondary transfer device 8 and an intermediate transfer cleaning device 9 are disposed around the intermediate transfer body 6.

  In the electrophotographic process section, image data is scanned onto the uniformly charged photoreceptor 1 by a laser beam or the like. As a result, a toner image is formed on the photoreceptor 1 by any one of the magenta developing unit 3M, the cyan developing unit 3C, the yellow developing unit 3Y, and the black developing unit 3K. This toner image is transferred to the intermediate transfer member 6. The magenta developing unit 3M, the cyan developing unit 3C, the yellow developing unit 3Y, and the black developing unit 3K respectively store different color toners (magenta, cyan, yellow, and black). In the case of forming a single color image, the toner image transferred to the intermediate transfer member 6 is transferred to the sheet as it is. However, in the case of forming a full-color image, toner images individually formed with four types of magenta, cyan, yellow, and black toners are superimposed on the intermediate transfer body 6 and then transferred onto a sheet. The photosensitive member 1 and the intermediate transfer member 6 are cleaned by the cleaning devices 4 and 9 after the primary transfer or the secondary transfer.

  The paper supply unit 81 stores a transfer paper on which a toner image is transferred. This transfer sheet is conveyed to the secondary transfer unit. In order to align the leading edge of the transfer paper and the leading edge of the image, the sheet is conveyed by a registration roller (not shown) at the same timing. The fixing unit 10 is a device for fixing the toner image transferred on the sheet, and the toner image is transferred in the toner image secondary transfer unit between the intermediate transfer body 6 and the secondary transfer unit 8. The sheet is conveyed and sent to the fixing unit 10. The fixing unit 10 is generally composed of a so-called fixing roller 10a for fixing toner on transfer paper and a pressure roller 10b for applying pressure from the back side of the transfer paper. In place of the fixing roller and the pressure roller, a belt may be used instead of the roller. Further, the fixing roller 10a side may be a type using a transfer belt in order to obtain a large fixing nip.

  By the way, in a color machine and a high-speed machine, a large amount of energy is required for fixing, and thus a heating element such as a heater is often used for both the fixing roller and the pressure roller. Further, in order to shorten the rise time (first copy time) until the printing operation is possible after the power is turned on, a heater that generates a large amount of heat is used as the heater used in the fixing device. The heater used in this fixing device may be an induction heating type. Moreover, what has multiple heaters as a heat source may be used. FIG. 9 shows a case where the heater of the fixing unit 10 has two configurations, that is, a fixing heater 10c and a pressure heater 10d.

  The writing unit 82 includes two semiconductor lasers that carry and output the image data processed by the image data processing unit, a polygon scanner equipped with a polygon mirror that deflects the laser beam at a uniform angular velocity, and a laser beam that is deflected at a uniform angular velocity. Is composed of an optical element having an fθ characteristic for correcting so as to be deflected at a constant speed on the photosensitive drum of the electrophotographic process section, and a synchronization detection section for generating a synchronization signal for each line. The number of the semiconductor lasers may be one. Alternatively, an LD array that outputs a plurality of outputs in one package may be used.

Next, the operation of the engine control unit for full color printing will be described. A case will be described in which toner images are formed in the order of magenta, cyan, yellow, and black. The controller instructs the start of image formation. Then, the polygon scanner starts rotating, the main motor is driven, and the photosensitive member and the fixing roller start rotating.
The latent image is formed by writing the bitmap data developed in the control unit as laser light onto a photoconductor uniformly charged in advance by a charger. The latent image is visualized with toner, and a color image is output.

  Specifically, first, magenta component data is output as laser light. An electrostatic latent image is formed on the photoreceptor by this laser light. Magenta toner is adhered to the electrostatic latent image. The magenta toner image is transferred to the intermediate transfer member. Subsequently, cyan component data is output as laser light. An electrostatic latent image is formed on the photoreceptor by this laser light. Cyan toner is attached to the electrostatic latent image. The cyan toner image is transferred so as to be superimposed on the magenta toner image on the intermediate transfer member.

  Subsequently, yellow component data is output as laser light. An electrostatic latent image is formed on the photoreceptor by this laser light. Yellow toner is adhered to the electrostatic latent image. The yellow toner image is transferred so as to be superimposed on the magenta and cyan toner images on the intermediate transfer member.

  Further, black component data is output as laser light. An electrostatic latent image is formed on the photoreceptor by this laser light. Black toner is adhered to the electrostatic latent image. The black toner image is superimposed on the magenta, cyan, and yellow toner images on the intermediate transfer member. As a result, toner images of four colors of magenta, cyan, yellow, and black are superimposed on the intermediate transfer member. The four-color toner images are transferred onto the paper at a time, conveyed to the fixing unit, and fixed.

  Next, the operation of the engine control unit in the case of duplex printing will be described. At the time of double-sided printing, the single-sided printed transfer paper passes through the fixing device and is then transported to the double-sided printing unit by a transport path switching means (not shown). Here, the transfer sheet is reversed and conveyed again to the registration roller unit. Subsequently, the registration roller is driven in a timely manner to align the leading edge of the transfer paper and the leading edge of the image, and the image is transferred to the back side of the transfer paper that has been printed on one side. Then, after the image is fixed on the transfer paper by the fixing unit, the transfer paper is conveyed to the paper discharge unit.

  Further, in the color copying machine shown in FIGS. 8 and 9, a plurality of heaters (heating sources) for preventing dew condensation of each component and the like in the copying machine main body 41 are not clearly shown in the drawings. ) Is arranged. Examples of the heater include an optical dew heater in the scanner unit, a charging / drum heater, and a dehumidifying heater that prevents moisture absorption of the transfer paper. These are arranged at predetermined positions in the copying machine main body 41. The optical dew heater is for preventing image defects due to dew condensation occurring on the mirror 85 and the lens 86. The charging / drum heater is for preventing image defects and jamming due to winding of paper by keeping the charging roller / drum constituting the charger warm and preventing condensation. The dehumidifying heater prevents the paper (recording paper) set in the paper feed cassette of the paper feed unit 81 and the extended paper feed tray 45 from getting wet and causing a paper jam, a transfer paper transfer failure and a transfer rate. This is to prevent a decrease.

  Next, the configuration and operation of the power supply circuit of the copying machine will be described with reference to FIG. FIG. 12 is a diagram showing a power supply circuit of the copying machine. As shown in FIG. 12, in this circuit, an AC power source 21 is connected, a fuse 22 is connected to a hot line 23, and a power switch 25 and a relay circuit 34 are connected. The neutral line 24 is connected to the power switch 25 and the relay circuit 34. The power switch 25 includes two changeover switches, and is configured to be able to be switched in conjunction with each other by a user operation. When the power switch 25 is turned on, the circuit of the DC power supply unit 26 is activated and a DC voltage is generated. The hot line 23 and the neutral line 24 connected to the relay circuit 34 are connected to dehumidifying heaters 31 and 33 which are heating sources, and the dehumidifying heaters 31 and 33 are turned on when the relay contacts are connected. Configured.

  Although the relay circuit 34 is described as a double-cut relay, a single-cut relay that switches only the hot line 23 may be used. Further, the relay circuit 34 is configured by a relay having a contact point connected to + 24V which is a direct current power source produced by the DC power source unit 26. The relay circuit 34 is configured as a break contact type relay circuit in which a contact is connected when 24 V is not applied and a contact is separated when 24 V is applied. A diode D1 for preventing back electromotive force is inserted at both ends of the relay.

  In the power supply circuit shown in FIG. 12, no voltage is applied across the relay circuit 34 when the power switch 25 is turned off. Therefore, the contact of the relay circuit 34 is connected, power is supplied to the dehumidifying heaters 31 and 33, and power is turned on to the dehumidifying heaters 31 and 33.

  On the other hand, when the power switch 25 is turned on, a DC voltage of +24 V is generated by the DC power supply unit 26, so that a voltage is applied across the relay circuit 34. Then, the contacts of the relay circuit 34 are separated from each other, and the dehumidifying heaters 31 and 33 are turned off.

  Here, the energy saving mode of the copying machine will be described. When the copy is not used for a certain period of time, the copying machine shifts to the first energy saving mode. In this energy saving mode, the control target temperature of the fixing device is set lower than usual, or the temperature control of the fixing device is stopped.

  Furthermore, if the unused time of the copying machine becomes long, the + 24V DC power supply, which is the load system power to the motor, clutch, solenoid, etc. used in the copying machine is shut off, and the second Transition to energy saving mode. This mode is entered when a certain time has elapsed since the energization of the fixing device was stopped.

  If this state continues, the temperature inside the machine decreases, and problems such as image defects and paper jams occur due to condensation and moisture absorption of the transfer paper. Therefore, in order to eliminate this, it is necessary to turn on the dehumidifying heaters 31 and 33. However, in the power supply circuit shown in FIG. 12, when the copying machine is in the energy saving mode, the power switch 25 is in the ON state, and thus the dehumidifying heaters 31 and 33 cannot be in the ON state.

  Next, in the copying machine, considering the transfer conditions of the image to be formed and the transferability of the transfer paper, it is better to keep the dehumidification heater energized while using the copying machine. The problem in this case is described.

  First, the first problem will be described. For example, in a copier having a power supply circuit that controls a dehumidifying heater using a break contact type relay circuit shown in FIG. 12, the dehumidifying heater is not normally energized. In general, after an arbitrary time set in consideration of the copy output time from the end of the copying operation of the machine, + 24V applied to the relay circuit is set to 0V and the energy saving mode is entered. In the energy saving mode, the relay circuit contacts are connected and the dehumidifying heater is energized.

  Also, depending on the user, in order to shorten the output time, an energy saving mode in which the control target temperature of the fixing device is set lower than usual is set, and the energy saving mode in which + 24V applied to the relay circuit is set to 0V is not shifted. In some cases. In this case, when the main SW is ON, the dehumidifying heater is not energized, and the conditions are severe due to the transfer conditions of the image to be formed and the transfer paper transfer problem.

  Next, the second problem will be described. Always turning on the dehumidifying heater means that the power consumption for machine operation must always be considered by subtracting the dehumidifying heater. In particular, in order to shorten the machine start-up time after the power is turned on, the amount of power supplied to the fixing device is reduced accordingly.

  Next, the third problem will be described. When the fixing roller or the like reaches the pre-rotation start temperature, image forming condition optimization control called process control is started in order to optimize the image forming condition. At this time, the power consumption of the entire machine reaches its peak. That is, the AC power consumption required for controlling the fixing device must be covered by subtracting the amount of power consumed by the DC power source during the process control operation from the effective power consumption of the entire machine. Therefore, when the dehumidifying heater is always turned on, the AC power consumption required for controlling the fixing device is reduced by the corresponding power consumption.

  Next, the fourth problem will be described. As an option of the machine body, for example, there is an extended paper feed tray, and usually a dehumidifying heater is mounted. Compared to the case where the extended paper feed tray is not connected, when it is connected, the required power increases by the amount of power consumed by the dehumidifying heater.

  Next, based on the above problems, the purpose of this embodiment will be described. In recent years, there is an increasing demand for speeding up the machine and shortening the rise time of the machine, and the power required for the fixing device is increasing. And the power consumption of an apparatus needs to satisfy | fill the rated power of a household commercial power supply, and must satisfy | fill an energy star standard. In this situation, it is an object of the present embodiment to provide an image forming apparatus that is equipped with a dehumidifying heater so that stable transfer, conveyance, and fixing can be performed, and the rise time of the apparatus is shortened. It is.

Here, in order to achieve the object of the present embodiment, the present embodiment will be described with reference to FIG.
FIG. 1 is a schematic circuit diagram of a power supply circuit of a copying machine according to an embodiment of the present invention. As shown in FIG. 1, in this circuit, an AC power source 21 is connected, a hot line 23 is connected to a fuse 22, and is directly connected to a power switch 25, dehumidifying heater connection detecting means 30, 31 and a dehumidifying heater. The The neutral line 32 is connected to the power switch 24, the dehumidifying heater connection detecting means 30, 32, and the dehumidifying heaters 31, 33. The power switch 25 includes two changeover switches, and is configured to be able to be switched in conjunction with each other by a user operation. When the power switch 25 is turned on, the circuit of the DC power supply unit 26 is activated, and the control unit 27 and other device units are activated. When the apparatus is activated, the CPU 28 of the control section 27 controls the fixing control section 29 and other sections of the apparatus to perform a copy operation, an operation for shifting to the energy saving mode, and the like.

  First, as shown in FIG. 1, the connection between the dehumidifying heaters 31 and 33 and the AC power supply 21 is configured not to pass the relay circuit 34 shown in FIG. 12. As a result, the dehumidifying heaters 31 and 33 are always operable regardless of whether the power switch is on or off. Therefore, the dehumidification or dew condensation prevention heater can be operated at any time during copying operation, standby in energy saving mode, or when the apparatus is not used such as at night. As a result, it is possible to prevent paper jamming, transfer paper conveyance failure, image failure, and the like. In FIG. 1, the dehumidifying heaters are shown as dehumidifying heaters 31 and 33, but the number of dehumidifying heaters to be mounted is not limited by various systems of the copying machine.

Next, when the temperature of the fixing device is cold in order to satisfy the rated power of the commercial power supply for home use and to accelerate the rise time of the fixing device, the load (motor, clutch, solenoid) driven by the DC power supply of the drive system Etc.) and the power consumption is distributed to the heater control of the fixing device.
Specifically, the operation of the DC power load is stopped by the circuit operation of the control unit 27 shown in FIG. 1 until the fixing device reaches the fixable temperature. Therefore, the energization to the fixing heater 10c and the pressure heater 10d shown in FIG. As a result, the temperature of the fixing device can be raised to the target temperature in a shorter time.

  Next, when the fixing device reaches the fixable temperature, the two heaters in the fixing device are controlled not to be turned on simultaneously but to be turned on alternately by the operation of the control unit 27. With this control, it becomes possible to use the power of the two heaters 10c and 10d with less wattage with a DC load.

  In the fixing device after the fixing device reaches the fixing possible temperature, the temperature of the fixing roller is made uniform, and the temperature state at the fixing nip portion is improved. Then, a DC brushless motor for driving the fixing device is driven, and then image forming condition optimization control called process control is started in order to optimize the image forming condition as necessary.

  Here, the timing for moving the load of the DC system is generally not delayed at the time of controlling the two heaters alternately when the fixing device reaches the fixing possible temperature, but is delayed for an appropriately determined time. It is. This is because, even after the fixing device reaches the fixing possible temperature, one fixing heater is lit, so the temperature of the fixing device rises, and it is necessary to take that into consideration.

  Next, by the operation of the control unit 27, only during the process control operation at the time of starting the machine, the power supply energy to the fixing heater is reduced, and control for distributing the power to the dehumidifying heaters 31 and 33 is performed. . Further, the connection of the dehumidifying heaters 31 and 33 when the option is installed is detected by using the dehumidifying heater connection detecting means 30 and 32, and when the option is not installed, control is performed to use the usable AC power for energizing the fixing heater. To do. This will be specifically described below.

  FIG. 2 is a diagram showing the AC power supply waveform and the state of the zero cross signal. FIG. 4 is a diagram illustrating a state where the fixing heater is 100% energized. As shown in FIG. 2, the timing of the AC power supply and the zero cross signal is defined. When the zero cross signal is used as a trigger, a one-shot timer is operated, and a control signal is generated by the function of the CPU of the control unit. As a result, when the driving of the fixing heater is stopped for a set time, as shown in FIG. The duty of energization to the can be changed. A triac is used for energizing the actual fixing heater. This control is performed only during the process control operation at the time of starting up the machine, and the power supply energy to the fixing heater is reduced. And the control part 27 performs control which distributes the electric power for that to the dehumidification heaters 31 and 33.

  Further, the dehumidification detecting means 30 and 32 shown in FIG. 1 detect the connection of the dehumidifying heaters 31 and 33 when the option is mounted, and control is performed to use the usable AC power to energize the fixing heater when the option is not mounted. To do. FIG. 3 is a diagram illustrating a state where the fixing heater is 100% energized. As shown in FIG. 3, when the fixing heater can be energized 100%, if the set value of the one-shot timer is set to zero, the fixing heater can be energized with a duty of 100%.

  FIG. 5 is a follow chart for explaining the control to the fixing heater of the present invention. As shown in FIG. 5, the control of the fixing heater first detects the detection status of the optional dehumidifying heater using the dehumidifying heater connection detecting means, and determines whether or not to use the dehumidifying heater. As a result, the CPU of the control unit determines the application duty of the fixing heater and performs control for adjusting the power supplied to the fixing heater.

  FIG. 6 is a diagram showing the transition of the power consumption at the time of actual power-on of the copying machine to which the present invention is not applied. When the power is turned on, the two fixing heaters in the fixing device are turned on. In consideration of inrush current, it is desirable to turn on with a slight time difference. At the timing A in the figure, the temperature inside the fixing device rises, reaches the pre-rotation start temperature, and a DC brushless motor that rotates the roller of the fixing device is driven to make the temperature of the fixing roller uniform. Thereafter, since process control control is performed with the timing width B entered in the figure, the total power consumption of the copying machine exceeds the rated power of 1500 W of the commercial power source for home use. If the present embodiment is applied at the timing B in FIG. 6 and the energization duty to the fixing heater is lowered as shown in FIG. 4, the machine can be operated without exceeding the rated power of 1500 W of the household commercial power supply. it can. Note that the power consumption value of the connected dehumidifying heater is stored in advance, so that when the connection is detected, the fixing heater is energized with a preset duty according to the total power amount of the dehumidifying heater. Is called.

  Therefore, according to the present exemplary embodiment, the rise time of the fixing device can be shortened by the control. Also, the first print time can be shortened. Further, when the dehumidifying heater is operated, it is possible to prevent an image defect, a paper jam, or a transfer paper conveyance defect. Actually, the time to warm up the fuser after turning on the power is only a few tens of seconds, and only during this time, the amount of power supplied to the fixing heater is reduced, shortening the machine startup time. There is no problem because it only has a slight impact on

  FIG. 7 is a schematic circuit diagram showing a power supply circuit of a copying machine according to another embodiment to which the present invention is applied. In FIG. 7, a plurality of dehumidifying heaters are used for the purpose of the copying machine. The dehumidifying heater a35 is a type of heater that needs to be energized only when the power is turned off or in the power saving mode. The dehumidifying heaters 31 and 33 are classified into heaters that are desired to be energized at all times. The dehumidifying heater a35 is supplied with electric power via a relay circuit 34 using break type contacts provided in the circuit. Further, the dehumidifying heaters 31 and 33 are supplied with electric power without going through the relay circuit 34 using break type contacts. In FIG. 7, the dehumidifying heater a35 and the dehumidifying heaters 31 and 33 are shown, but the number is not limited by the dehumidifying heater mounted in the system.

  In the above invention, since a control mechanism for performing energization control of the fixing heater is originally used, there are no additional parts and circuits such as energization to the dehumidifying heater, which is advantageous in terms of cost. In the example described above, the dehumidifying heater has been described as an example, but the object can be similarly achieved with an optical dew condensation heater, a charging / drum heater, and the like.

1 is a schematic circuit diagram showing a power supply circuit of a copying machine according to an embodiment of the present invention. It is a figure for demonstrating the timing of the AC power supply waveform and zero cross signal of one Embodiment of this invention. It is a figure for demonstrating 100% electricity supply to the fixing heater of one Embodiment of this invention. It is a figure for demonstrating the electricity supply Duty to the fixing heater of one Embodiment of this invention. It is a figure which shows the timing chart for demonstrating operation | movement of one Embodiment of this invention. It is a figure which shows the power consumption measurement result of the copying machine for demonstrating the operation phenomenon of one Embodiment of this invention. It is a schematic circuit diagram which shows the power supply circuit of the copying machine of other embodiment of this invention. 1 is a schematic view of a color copying machine of the present invention. 1 is a configuration diagram of a color copying machine of the present invention. It is a schematic circuit diagram showing a power supply circuit of a conventional copying machine. It is a schematic circuit diagram showing a power supply circuit of another conventional copying machine. 1 is a schematic circuit diagram for explaining a power supply circuit of a copying machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Color developing device group 3M Magenta developing device 3C Cyan developing device 3Y Yellow developing device 3K Black developing device 4 Photoconductor cleaning device 5 Static elimination lamp 6 Intermediate transfer body 7 Primary transfer machine 8 Secondary transfer machine 9 Intermediate transfer member cleaning device 10 Fixing device 81 Paper feed unit 82 Writing unit 83 Scanner 84 Lamp 85 Mirror 86 Lens 87 CCD
D1 diode

Claims (9)

A pressurized heat source connection detecting means for detect the connection state of the first heat source for heat insulating the predetermined portion of the images forming apparatus,
A fixing device have a heating element and a second heat source,
Have a, and control means for DUTY controlling the power supply to the fixing unit,
The first heating source can be connected to an AC power source that supplies power to the apparatus body regardless of whether the image forming apparatus is powered on or off.
When the connection of the first heating source is detected by the heating source connection detection unit, the control unit determines the first heating source and the fixing device according to the power consumption of the first heating source. the total power consumption so as to be less available power from the AC power source, an image forming apparatus, characterized in that to change the energization DUTY to the fuser. A break contact type relay circuit for supplying power to the third heating source ;
The power ON includes at least a first mode capable of printing and a second mode for realizing energy saving ,
The relay circuit, the off when the printable first mode, the image forming apparatus according to claim 1, wherein that you turn on when the second mode of realization of the energy saving. A heating source connection detecting means for detecting a connection state of the first heat source for heat insulating the predetermined portion of the images forming apparatus,
A fixing device have a heating element and a second heat source,
The energization of the fixing device a heating source control method for an image forming apparatus having a control means for DUTY control and,
The first heating source can be connected to an AC power source that supplies power to the apparatus body regardless of whether the image forming apparatus is powered on or off.
When the control unit detects the connection of the first heating source by the heating source connection detection unit, the first heating source and the fixing device according to the power consumption of the first heating source. A method of controlling a heating source , comprising the step of changing energization DUTY to the fixing device so that the total power consumption of the power source becomes equal to or less than the power usable from the AC power source. There are a plurality of the first heating sources,
  The image forming apparatus according to claim 1, wherein the heating source connection detecting unit is provided for each of the first heating sources. The fixing device has fixing temperature detecting means for detecting temperature information of the heating member,
A DC power supply circuit that is activated when the image forming apparatus is powered on and generates a DC voltage;
The power supply to the load of the drive system supplied with power by the DC power supply circuit is stopped until the fixing device reaches the fixable temperature or until a predetermined time after reaching the fixable temperature; and the power that has been supplied to the load of the drive system, the energizing control means for supplying and adding to the fixing device, according to claim 1, characterized in that to have a, according to any one of 2, 4 Image forming apparatus. The second heating source is two heaters,
Claims wherein the fixing device is simultaneously or subsequently reaches the fixable temperature a predetermined time, the two heaters are allowed to simultaneously lit, characterized in that it have a current supply control means for controlling so as to alternately turned on 5. The image forming apparatus according to 5 . There are a plurality of the first heating sources,
  The image forming apparatus according to claim 3, wherein the heating source connection detecting unit is provided for each of the first heating sources. The fixing device has fixing temperature detecting means for detecting temperature information of the heating member,
Power is supplied by a DC power supply circuit that starts up when the image forming apparatus is turned on and generates a DC voltage until the fixing device reaches a fixing temperature or until a predetermined time after the fixing temperature is reached. The method further comprises a step of stopping power supply to the load of the driving system and adding the power supplied to the load of the driving system to the fixing device. 2. The heating source control method described in 1. The second heating source is two heaters,
9. The method according to claim 8, further comprising a step of controlling the two heaters that are simultaneously turned on at the same time when the fixing device reaches a fixable temperature or at a predetermined time thereafter to alternately turn on the two heaters . Heat source control method.

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