JP4680683B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a fixing unit that fixes toner onto a recording sheet with heat.

  An image forming apparatus such as a copying machine includes a fixing device that fixes toner transferred onto a recording sheet to the recording sheet with heat and pressure. This fixing device heats the fixing heater using electric power from a commercial power source, but as an energy saving measure, there is an apparatus having an energy saving mode in which power supply to the fixing heater is stopped and waiting for printing. . In an image forming apparatus having an energy saving mode, the temperature of the fixing heater once the power supply has been stopped falls below a temperature at which fixing can be performed. Therefore, when returning from the energy saving mode to the printing mode, the temperature of the fixing heater is reduced. A waiting time (rise time) until a predetermined temperature is reached is required.

  If a large amount of power is used to return to the print mode, the temperature of the fixing heater can be raised rapidly. However, the commercial power supply in Japan has a maximum of 1500 W at 100 V and 15 A, and the temperature rise time There is a limit to shortening. Therefore, for example, as shown in Patent Document 1 below, in order to shorten the rise time, a chargeable auxiliary power source (capacitor or battery) is provided, and in the energy saving mode, the auxiliary power source is charged by a commercial power source. An image forming apparatus that shortens the rise time by flowing a large current to the fixing heater using both a commercial power supply and an auxiliary power supply when returning to the print mode has been proposed.

  Here, the characteristics of the electric double layer capacitor suitable for the capacitor as the auxiliary power source and the lithium ion battery suitable for the battery as the auxiliary power source will be described. The electric double layer capacitor is characterized in that it can be charged / discharged with a large current and has a relatively long charge / discharge life (for example, on the order of several hundred thousand times), but the voltage drops rapidly. Therefore, in order to supply power for a long time, it is necessary to increase the capacity, which is expensive.

In addition, the lithium ion battery is characterized in that the voltage drop until the end of discharge is small. Therefore, it is possible to supply electric power for a long time at a lower cost compared with the electric double layer capacitor. However, the lithium ion battery has a property that its life is shortened as charging and discharging are repeated with a large current. When the halogen heater used for the fixing heater is lit from a state cooled to about room temperature, a large inrush current flows to the halogen heater and a current nearly 10 times the rated current may flow. In the case where it is carried out, the life of the repeated number of times of charging and discharging of the lithium ion battery is relatively short, about 500 to 1000 times.
Japanese Patent Laid-Open No. 10-282821

  However, when returning from the energy saving mode to the printing mode as described above, when an electric double layer capacitor is used as an auxiliary power source when a large current is supplied from both the external power source and the auxiliary power source to the fixing heater, the electric double layer capacitor is discharged. Since the voltage drops rapidly from the beginning, it is necessary to increase the capacity to enable long-time use, and the electric double layer capacitor becomes expensive. In addition, the halogen heater used in the fixing roller generates a large current when it is lit from a cold temperature of about room temperature. Therefore, when a lithium ion battery is used as an auxiliary power source, charging and discharging must be repeated with a large current. The life of the lithium ion battery is shortened.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides a fixing device and an image forming apparatus that have a long life of an auxiliary power source and an inexpensive image forming apparatus while shortening the time required to raise the temperature of the fixing unit to a fixable temperature. The purpose is to provide.

The invention according to claim 1 is a first auxiliary power source comprising a capacitor;
A second auxiliary power source comprising a secondary battery;
A first fixing heater that heats a fixing unit that fixes toner onto a recording sheet with electric power from the first auxiliary power source, and a second fixing heater that includes a halogen heater and heats the fixing unit with electric power from the second auxiliary power source A fixing heater having a third fixing heater that heats the fixing unit with electric power from an external power source;
First charge / discharge switching means for switching between discharging the first auxiliary power and supplying the first auxiliary power to the first fixing heater, or charging the first auxiliary power with power from an external power source;
Second charge / discharge switching means for switching whether to discharge the power of the second auxiliary power source and supply it to the second fixing heater, or to charge the second auxiliary power source with power from the external power source;
Third fixing heater driving means for switching whether or not to drive the third fixing heater with electric power from the external power source;
Temperature detecting means for detecting the temperature of the second fixing heater,
At the start of driving the fixing heater, the third fixing heater driving means drives the third fixing heater, switches the first charge / discharge switching means to the discharge side, drives the first fixing heater, and detects the temperature. When the temperature of the second fixing heater detected by the means rises to a temperature at which a rated current flows through the second fixing heater, the second charge / discharge switching means is switched to the discharge side to drive the second fixing heater. And an image forming apparatus provided with a control means for starting the operation.

  A second aspect of the present invention is the image forming apparatus according to the first aspect, wherein the temperature detecting means includes a thermistor provided in the second fixing heater.

  In these configurations, when driving the fixing heater is started, first, the third fixing heater driven by the power of the external power source and the first fixing heater driven by the power of the first auxiliary power source composed of a capacitor are driven. Thus, the second fixing heater driven by the power from the second auxiliary power source composed of the secondary battery rises to the temperature at which the rated current flows through the second fixing heater due to the radiant heat of the first and third fixing heaters. The drive is started when you do.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the control unit is configured by the third fixing heater driving unit when the recording paper is carried into the fixing unit. Driving the third fixing heater, switching the first charging / discharging switching means to the charging side to stop the first fixing heater, and driving the second fixing heater as the discharging side by the second charging / discharging switching means It is.

  In this configuration, when the recording paper is carried into the fixing unit, the first fixing heater is stopped and the third fixing heater and the second fixing heater are driven so that a stable current can continue to flow for a long time. The fixing heater is heated by using a secondary battery and an external power source as a power supply source.

  According to the first aspect of the invention, the following effects can be obtained. When the second fixing heater composed of a halogen heater is turned on from a cooled state, a large inrush current that greatly exceeds the rated current flows at the start of lighting. However, in the case of the invention according to claim 1, After the two fixing heaters are heated, for example, by their radiant heat generated by driving the first and third fixing heaters to reach the rated current value, the power from the second auxiliary power source composed of the secondary battery is supplied to the second fixing heater. Therefore, the current flowing from the second auxiliary power source composed of the secondary battery to the second fixing heater becomes the rated current, and charging / discharging is not repeated with a large current, so that the lifetime can be kept long.

  In addition to the third fixing heater, the first and second fixing heaters are heated by the electric power from the first and second auxiliary power supplies, so that the waiting time until the temperature of the fixing unit reaches a fixable temperature (rise time) Time). As a result, the heaters of the fixing unit can be turned off at the time of printing standby, so that significant power saving can be achieved.

  According to the second aspect of the present invention, since the thermistor is used as the temperature detecting means, a configuration for detecting the temperature of the second fixing heater with a simple configuration can be realized.

  According to the third aspect of the present invention, when the recording paper is carried in which the heat is absorbed in the recording paper and the temperature of the fixing unit is likely to decrease, the secondary battery and the external power source that can continue to flow a stable current for a long time are used as power. Since the fixing heater is heated as a supply source, the fixing heater can be stably heated without relying on unstable power supply from the first auxiliary power source including a capacitor whose voltage drops when the electric charge is discharged.

  Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an internal configuration of a multi-function peripheral which is an embodiment of an image forming apparatus according to the present invention. In particular, a fixing heater control mechanism for controlling on / off of a fixing heater for heating a fixing roller is mainly shown. FIG. FIG. 2 shows each state type of the multifunction device 1 (plug-in state, initial startup state, print state, ready state, sleep state, and rapid startup state) and an opportunity to transition from each state to another state. This is state transition information indicating the type of event. Note that the image forming apparatus according to the present invention may be, for example, a printer, a copier, a facsimile machine, or the above-described multifunction machine having these functions. In this embodiment, an image forming apparatus according to the present invention will be described by taking a multifunction peripheral as an example. In the multi-function machine 1, the fixing roller (not shown) is a recording paper on which a toner image is transferred from a photosensitive drum, nipped by a heat roller and a pressure roller (not shown), and the toner image is formed by heat and pressure. It is fixed on the recording paper.

  The external power source 2 is a so-called commercial power source, for example, and is an AC (alternating current) power source by an electric power company. The power supply control circuit 9 controls whether or not the power from the external power supply 2 is supplied to each part of the apparatus in response to turning on or off of the main switch 10 that is a main power switch for starting the multifunction machine 1. .

  The multifunction device 1 includes an image forming unit 11, an instruction receiving unit 12, a timer 13, a fixing roller temperature sensor 14, a control unit 15, a first fixing heater 17, an electric double layer capacitor 18, a capacitor charge / discharge changeover switch 19, and a capacitor charge control. Circuit 20, second fixing heater 21, second fixing heater temperature detection unit 22, lithium ion battery 23, battery charge / discharge switch 24, battery charge control circuit 25, third fixing heater 26, and third fixing heater drive circuit 27 Is provided.

  The image forming unit 11 performs image formation for forming a toner image on recording paper. The multifunction device 1 operates in response to a print instruction when, for example, a copy function, a printer function, or a facsimile reception function is executed. . The instruction receiving unit 12 receives various operation execution instructions from the user or the like with respect to the multifunction machine 1, and receives, for example, execution instructions for a copy function, a printer function, and a facsimile reception function. In the instruction receiving unit 12, a copy function execution instruction is input to the multifunction device 1 by the user from the operation panel (not shown) of the multifunction device 1. The printer function execution instruction is transmitted to the multifunction device 1 from, for example, a PC (personal computer) connected to the multifunction device 1 via a network or the like. The facsimile reception execution instruction is transmitted to the multifunction device 1 from a facsimile transmission device connected to the multifunction device 1 through a public line or the like.

  The timer 13 measures the elapsed time from the time when the instruction is received from the state determination unit 152. The fixing roller temperature sensor 14 measures the temperature of the fixing roller and outputs it to the fixing roller temperature control unit 151 and the like.

  The first fixing heater 17, the second fixing heater 21, and the third fixing heater 26 are heaters for heating the fixing roller, and in the present embodiment, are composed of halogen heaters. The first fixing heater 17 is, for example, a 1300 W DC (direct current) heater. The second fixing heater 21 is a DC heater of 500 W, for example. The third fixing heater 26 is, for example, a 1200 W AC (alternating current) heater. The first fixing heater 17 uses a large power consumption in order to heat rapidly by flowing a large current. The first fixing heater 17, the second fixing heater 21, and the third fixing heater 26 are installed adjacent to each other.

  The electric double layer capacitor (first auxiliary power source) 18 functions as a power source for driving the first fixing heater 17. The electric double layer capacitor 18 can be charged and discharged with a large current. The electric double layer capacitor 18 has a characteristic that the charge / discharge repetition life is relatively long (for example, on the order of several hundred thousand times), but the electric power (voltage) rapidly decreases when the electric charge is discharged. The charging time of the electric double layer capacitor 18 is several tens of seconds, for example.

  The capacitor charge / discharge changeover switch 19 (first charge / discharge changeover means) either (1) discharges the electric double layer capacitor 18 and drives the first fixing heater 17 using the electric double layer capacitor 18 as a power supply source, or (2 This is a switch for switching whether to charge the electric double layer capacitor 18 using the external power source 2 as a power supply source. When the switch is switched to the charge side, the electric double layer capacitor 18 is charged, and when the switch is switched to the discharge side, the first fixing heater 17 is driven.

  The capacitor charge control circuit 20 (first charge / discharge switching means) determines whether or not to charge the electric double layer capacitor 18 by switching whether or not the electric power from the external power source 2 is supplied to the electric double layer capacitor 18. Switch to switch. The capacitor charge / discharge changeover switch 19 is switched to the side where the electric double layer capacitor 18 is charged, and the capacitor charge control circuit 20 supplies power from the external power source 2 to the electric double layer capacitor 18, thereby The capacitor 18 is charged.

  The lithium ion battery (secondary battery, second auxiliary power source) 23 is a rechargeable power source that functions as a power source for driving the second fixing heater 21. The lithium ion battery 23 is characterized by a small voltage drop until the end of discharge. The charging time of the lithium ion battery 23 is, for example, 10 minutes.

  The battery charge / discharge changeover switch (second charge / discharge changeover means) 24 (1) discharges the lithium ion battery 23 and drives the second fixing heater 21 using the lithium ion battery 23 as a power supply source. This is a switch for switching whether to connect a circuit so that the lithium ion battery 23 is charged with the external power supply 2 as a power supply source.

  The battery charge control circuit (second charge / discharge switching means) 25 switches whether to charge the lithium ion battery 23 by switching whether to supply power from the external power source 2 to the lithium ion battery 23. It is. The battery charge / discharge switch 24 is switched to the side for charging the lithium ion battery 23, and the battery charge control circuit 25 supplies the power from the external power source 2 to the lithium ion battery 23, so that the lithium ion battery 23 is charged. Is done.

  The second fixing heater temperature detection unit (temperature detection means) 22 includes a thermistor, for example, and detects the temperature of the second fixing heater 21. The second fixing heater temperature detection unit 22 sends information indicating the temperature of the second fixing heater 21 to the state determination unit 152.

  The third fixing heater driving circuit (third fixing heater driving means) 27 determines whether to drive the third fixing heater 26 using the external power source 2 as a power supply source, that is, whether to heat the third fixing heater 26. It functions as a switch to switch between. When the third fixing heater driving circuit 27 is turned on, the third fixing heater 26 is driven, and when the switch is turned off, the third fixing heater 26 is stopped.

  The control unit 15 controls the overall operation of the multifunction machine 1, and includes a CPU (Central Processing Unit) that executes a program, a ROM (Read Only Memory) that stores the program, and a temporary storage area when the program is executed. It is comprised from RAM (random access memory) etc. which are used as. The control unit 15 includes a fixing roller temperature control unit 151, a state determination unit 152, and a switch control unit 153.

  The state determination unit (state determination unit) 152 determines whether the current state of the MFP 1 is in the initial startup state, the late startup state, the print state, the ready state, the plug-in state, or the sleep state. It is to be determined. The state determination unit 152 is in the on or off state of the main switch 10 sent from the power control circuit 9, the print instruction is not input from the instruction reception unit 12, and the second fixing heater temperature detection unit 22 Based on the temperature information sent or the like, it is determined which state the MFP 1 is in.

  In the initial start-up state, the temperature of the fixing roller can be fixed from when the multifunction device 1 is turned on (when the main switch 10 is turned on) or when a print instruction is accepted in the sleep state. The temperature of the second fixing heater 21 detected by the second fixing heater temperature detecting unit 22 is in a state up to a predetermined first temperature range (for example, 180 ° C.). This is a state until the temperature rises to a predetermined temperature (eg, 50 ° C.) at which the rated current flows.

  The late start-up state refers to the time from when the MFP 1 is turned on or after a print instruction is received in the sleep state until the temperature of the fixing roller reaches a predetermined first temperature range in which fixing is possible. This is a state after the temperature of the second fixing heater 21 detected by the second fixing heater temperature detecting unit 22 has reached the predetermined temperature.

  The print state is a state while the multifunction device 1 is performing a printing operation (a state from when printing (including copying) is completed until it is completed). In the printing state, the temperature of the fixing roller is kept within the first temperature range.

  The plug-in state is a state where the power plug is inserted into the outlet of the external power source 2 but the main switch 10 is turned off.

  The ready state is a state where the input of the print instruction is waited and the fixing roller can be immediately raised to the first temperature range if there is a print instruction. In this ready state, the temperature of the fixing roller is set to a second temperature range (for example, 90 ° C.) that is lower than the first temperature range.

  The sleep state is a state in which the first fixing heater 17, the second fixing heater 21, and the third fixing heater 26 are turned off in order to save power. When the print instruction is not input for a certain period of time, the sleep state starts from the ready state. Transition to sleep mode.

  The state determination unit 152 stores the state transition information shown in FIG. 2 in advance, and determines the current state (transition source state) and the state (transition destination state) that makes the next transition from the generated event. The state determination unit 152 sends information indicating the determined current state and the next transition state to the switch control unit 153.

  The fixing roller temperature control unit 151 obtains the temperature of the fixing roller from the fixing roller temperature sensor 14, and when the multifunction device 1 is in a printing state, the upper limit of the first temperature range in which the fixing roller temperature can be fixed. Until the battery charging / discharging switch 24 is switched to the discharging side (the side supplying power to the second fixing heater 21) until the fixing roller temperature reaches the upper limit of the first temperature range. The battery charging / discharging changeover switch 24 is repeatedly switched to the charging side (the side that charges the lithium ion battery 23 with power from the external power supply 2) until the lower limit of the first temperature range is reached. Keep within the temperature range of. The fixing roller temperature control unit 151 controls the third fixing heater drive circuit 27 so that the temperature of the fixing roller is within a predetermined second temperature range in the ready state, so that the third fixing heater 26 You may make it control on-off. These controls are performed via the switch control unit 153.

  The switch control unit (control unit) 153 is configured to switch the capacitor charge / discharge switch 19 for each current state of the multifunction machine 1 determined by the state determination unit 152 or based on an instruction from the fixing roller temperature control unit 151. The capacitor charge control circuit 20, the battery charge / discharge switch 24, the battery charge control circuit 25, and the third fixing heater drive circuit 27 are controlled.

  FIG. 3 is a diagram showing states of the capacitor charge / discharge changeover switch 19, the capacitor charge control circuit 20, the battery charge / discharge changeover switch 24, the battery charge control circuit 25, and the third fixing heater drive circuit 27 in each state of the multifunction machine 1. It is. The states of the capacitor charge / discharge changeover switch 19, the capacitor charge control circuit 20, the battery charge / discharge changeover switch 24, the battery charge control circuit 25, and the third fixing heater drive circuit 27 corresponding to each state of the multi-function device 1 are the switch control unit. 153 may be stored by itself, or may be stored in a storage unit (not shown) and read by the switch control unit 153 as necessary. Further, in the power supply control by the capacitor charge control circuit 20 and the battery charge control circuit 25, the case where the power is supplied is indicated as ON, and the case where the power is not supplied is indicated as OFF.

  In the initial start-up state, the capacitor charge / discharge switch 19 is switched to the side that discharges the electric double layer capacitor 18 (the side that supplies power to the first fixing heater 17), and the capacitor charge control circuit 20 is turned off. . On the other hand, the battery charge / discharge switch 24 is switched to the side for charging the lithium ion battery 23 (the side for charging the second fixing heater 21 with the power from the external power source 2), and the battery charge control circuit 25 is turned on. . Further, the third fixing heater driving circuit 27 is turned on, and the third fixing heater 26 is driven.

  In the late stage of startup, the capacitor charge / discharge switch 19 is switched to the side that discharges the electric double layer capacitor 18 (the side that supplies power to the first fixing heater 17), and the capacitor charge control circuit 20 is turned off. . Then, the battery charge / discharge changeover switch 24 switches the lithium ion battery 23 to the discharge side (side to supply power to the second fixing heater 21), and the battery charge control circuit 25 is turned off. The third fixing heater driving circuit 27 is turned on, and the third fixing heater 26 is driven.

  In the ready state, the capacitor charging / discharging changeover switch 19 is switched to the side for charging the electric double layer capacitor 18 with the electric power from the external power supply 2, and the capacitor charging control circuit 20 is turned on. Further, the battery charge / discharge changeover switch 24 is switched to the side for charging the lithium ion battery 23 with the electric power from the external power supply 2, and the battery charge control circuit 25 is turned on. The third fixing heater driving circuit 27 is turned on, and the third fixing heater 26 is maintained in a driven state (as described above, the temperature of the fixing roller is within a predetermined second temperature range. The on / off state of the third fixing heater 26 may be controlled under the control of the fixing roller temperature control unit 151).

  In the sleep state, the capacitor charging / discharging changeover switch 19 is on the side for charging the electric double layer capacitor 18 with electric power from the external power supply 2, and the capacitor charging control circuit 20 is turned on. The battery charge / discharge changeover switch 24 is on the side for charging the lithium ion battery 23 with the electric power from the external power supply 2, and the battery charge control circuit 25 is turned on. The third fixing heater drive circuit 27 is turned off, and the third fixing heater 26 is stopped.

  In the printing state, in order to keep the temperature of the fixing roller within the first temperature range in which the fixing roller can be fixed, switching of the battery charge / discharge switch 24 to the charging side or discharging side is obtained from the fixing roller temperature sensor 14. It is performed in a timely manner according to the fixing roller temperature. The third fixing heater driving circuit 27 is turned on, and the third fixing heater 26 is maintained in the driven state. The battery charge control circuit 25 is turned off. The capacitor charging / discharging changeover switch 19 is on the side for charging the electric double layer capacitor 18 with the electric power from the external power source 2, and the capacitor charging control circuit 20 is turned on.

  Next, a circuit image of the fixing heater control mechanism in the multifunction machine 1 according to the present invention will be described. FIG. 4 is a circuit diagram showing a circuit image (outline) of the fixing heater control mechanism.

  The external power source (AC) 2 is connected to the third fixing heater 26 via the third fixing heater driving circuit 27. The external power source 2 is connected to the first fixing heater 17 and the second fixing heater 21 via a diode 41 that rectifies AC current into DC current. As a result, a DC current flows through the first fixing heater 17 and the second fixing heater 21, and an AC current flows through the third fixing heater 26. The first fixing heater 17, the second fixing heater 21 and the third fixing heater 26 constitute a fixing heater 30.

  The circuit on the third fixing heater 26 side includes an external power source 2 and a third fixing heater 26, and a third fixing heater driving circuit 27 is connected between the external power source 2 and the second fixing heater 26. Yes. The second fixing heater driving circuit 27 can control whether or not the third fixing heater 26 is driven by the electric power from the external power source 2.

  The circuit to which the first fixing heater 17 is connected includes a capacitor charge control circuit 20, a capacitor charge / discharge switch 19, and an electric double layer capacitor 18. Whether or not the current from the diode 41 is supplied to the electric double layer capacitor 18 by the capacitor charge control circuit 20 is controlled. The capacitor charge / discharge changeover switch 19 is provided between the capacitor charge control circuit 20 and the electric double layer capacitor 18. The capacitor charge / discharge changeover switch 19 causes (1) the electric double layer capacitor 18 to be connected to the capacitor charge control circuit. Or connected to the side 20 and charged by the electric power from the external power source 2, or (2) the electric double layer capacitor 18 is connected to the first fixing heater 17 side to be discharged and the electric double layer capacitor 18 is discharged. The connection to drive the first fixing heater 17 with the power from is switched.

  The circuit to which the second fixing heater 21 is connected includes a battery charge control circuit 25, a battery charge / discharge switch 24, and a lithium ion battery 23. Whether or not the current from the diode 41 is supplied to the lithium ion battery 23 by the battery charge control circuit 25 is controlled. The battery charge / discharge changeover switch 24 is provided between the battery charge control circuit 25 and the lithium ion battery 23, and (1) the lithium ion battery 23 is connected to the battery charge control circuit 25 side by the battery charge / discharge changeover switch 24. Or connected to the external power source 2 and charged with power from the external power source 2 or (2) connecting the lithium ion battery 23 to the second fixing heater 21 side and discharging it, and using the power from the lithium ion battery 23 to 2 The connection to drive the fixing heater 21 is switched.

  The second fixing heater 21 is provided with a second fixing heater temperature detection unit 22 for detecting the temperature of the second fixing heater 21. The second fixing heater temperature detection unit 22 sends information indicating the detected temperature of the second fixing heater 21 to the state determination unit 152.

  Next, processing during fixing heater driving control in the multifunction machine 1 will be described. FIGS. 5 and 6 are flowcharts showing processing at the time of fixing heater driving control in the multifunction machine 1.

  When the power plug of the multifunction device 1 is attached to the outlet and a signal indicating the state is sent from the power control circuit 9 to the state determination unit 152, the state determination unit 152 indicates that the state of the multifunction device 1 is in the plug-in state. It is determined that it has become. If it discriminate | determines in this way, the switch control part 153 will switch the capacitor charging / discharging changeover switch 19 to the side by which the electric double layer capacitor 18 is charged with the electric power from the external power supply 2, and the capacitor charging control circuit 20 (2) The battery charge / discharge switch 24 is switched to the side where the lithium ion battery 23 is charged by the electric power from the external power source 2, the battery charge control circuit 25 is turned on, and (3) the third fixing heater is driven. The circuit 27 is turned off, and the third fixing heater 26 is stopped (S1). Thereby, charging of the electric double layer capacitor 18 and the lithium ion battery 23 is started by the power from the external power source 2.

  When the power control circuit 9 detects that the main switch (power switch) 10 of the multi-function device 1 is turned on (YES in S2), the power control circuit 9 confirms that the main switch 10 is turned on. The signal shown is sent to the state determination unit 152. When receiving the main switch-on signal, the state determination unit 152 determines that the state of the multifunction device 1 is the start-up initial state, and sends a signal indicating the device state to the switch control unit 153. Then, the switch control unit 153 (1) switches the capacitor charge / discharge switch 19 to the side that discharges the electric double layer capacitor 18 (the side that supplies power to the first fixing heater 17), and the capacitor charge control circuit 20 (2) The battery charge / discharge changeover switch 24 is maintained on the side where the lithium ion battery 23 is charged (the side where the lithium ion battery 23 is charged with the electric power from the external power source 2). (3) The third fixing heater drive circuit 27 is turned on to drive the third fixing heater 26 (S3). When the switching control is performed as described above, if the electric double layer capacitor 18 is charged, the first fixing heater 17 is driven by the electric power of the electric double layer capacitor 18 in addition to the third fixing heater 26.

  Thereafter, the information indicating the temperature of the second fixing heater 21 sent from the second fixing heater temperature detecting unit 22 to the state determining unit 152 is the above-described predetermined temperature (the second fixing heater 21 including a halogen heater). When the current flowing through the temperature reaches the rated current (for example, 50 ° C.) (YES in S4), the state determination unit 152 determines that the state of the multifunction device 1 is in the late state. And a signal indicating this device state is sent to the switch controller 153. The switch controller 153 (1) the capacitor charge / discharge changeover switch 19 is connected to the electric double layer capacitor 18 side, The state where the capacitor charge control circuit 20 is turned off is maintained, and (2) the battery charge / discharge switch 24 is connected to the side that discharges the lithium ion battery 23 (the second fixing heater 21 is supplied with power). The battery charging control circuit 25 is turned off, and (3) the third fixing heater driving circuit 27 is kept on and the third fixing heater 26 is driven (S5). When the switching control is performed as described above, since the current flows from the lithium ion battery 23 to the second fixing heater 21 after the second fixing heater 21 is warmed and the rated current flows, the lithium ion battery 23 has a large current. In this state, the temperature of the fixing roller obtained from the fixing roller temperature sensor 14 by the fixing roller temperature control unit 151 and the switch control unit 153 is the same as that described above. The process continues until it is detected that the first temperature range has been reached (NO in S6).

  When the temperature of the fixing roller reaches the first temperature range (YES in S6), the state determination unit 152 determines whether a signal indicating that a print instruction has been received from the instruction reception unit 12 has been input (S7). When a signal indicating that a print instruction has been received is input from the instruction reception unit 12 (YES in S7), the state determination unit 152 determines that the state of the multifunction device 1 is the print state, and indicates this apparatus state. A signal is sent to the switch control unit 153. The switch control unit 153 (1) turns on the third fixing heater drive circuit 27 and maintains the state where the third fixing heater 26 is driven. (2) The capacitor charge / discharge switch 19 is an electric double layer capacitor. 18 is switched to the side charged with the power from the external power source 2, the capacitor charge control circuit 20 is turned on, and (3) the battery charge / discharge switch 24 keeps the temperature of the fixing roller within the first temperature range. In addition, the connection to the charge side / discharge side is switched in a timely manner according to the fixing roller temperature sensor 14, and the battery charge control circuit 25 is turned off (S8). At the time of printing, depending on the sheet passing condition to the fixing roller, the heating of the fixing roller may be taken away by the recording paper only by the heating by the third fixing heater 26, so that the temperature of the fixing roller is reduced. This is to keep the temperature of the fixing roller constant.

  When printing is completed (YES in S9), the state determination unit 152 determines that the state of the multifunction device 1 is in the ready state, and sends a signal indicating the device state to the switch control unit 153. The switch control unit 153 switches (1) the capacitor charge / discharge switch 19 to the side that charges the electric double layer capacitor 18, turns on the capacitor charge control circuit 20, and (2) switches the battery charge / discharge switch 24 to the lithium Switching to the side to charge the ion battery 23, the battery charging control circuit 25 is turned on, and (3) the third fixing heater driving circuit 27 is turned on, and the state where the third fixing heater 26 is driven is maintained (S10).

  Even when the signal indicating that the print instruction is received from the instruction receiving unit 12 in S7 is not input to the state determining unit 152 (NO in S7), the state determining unit 152 sets the state of the multifunction device 1 to the ready state. When it is determined that the device status has been reached, this device status is sent to the switch control unit 153, and the processing of S10 is performed.

  When the state determination unit 152 determines that the state of the multifunction device 1 is the ready state, the state determination unit 152 performs the processing of S8 and measures the time elapsed from the time when the state of the multifunction device 1 is determined as the ready state. Start (S11). If a signal indicating that a print instruction has been received is input from the instruction receiving unit 12 to the state determining unit 152 during the elapsed time measurement by the timer 13 (YES in S12), the state determining unit 152 As a determination that the state 1 is the print state, the process of S8 is performed again.

  If the print instruction is not accepted (NO in S12) and the timer 13 measures that a predetermined time (for example, 1 minute) has elapsed (YES in S13), the state determination unit 152 determines that the multifunction device 1 It is determined that the state is the sleep state, and a signal indicating the device state is sent to the switch control unit 153. The switch control unit 153 switches (1) the capacitor charge / discharge switch 19 to the side that charges the electric double layer capacitor 18, turns on the capacitor charge control circuit 20, and (2) switches the battery charge / discharge switch 24 to the lithium Switching to the charging side of the ion battery 23, the battery charge control circuit 25 is turned on, and (3) the third fixing heater 26 is further stopped by the third fixing heater driving circuit 27 (S14). In this way, all of the first fixing heater 17, the second fixing heater 21 and the third fixing heater 26 are turned off, and the apparatus waits for a further print instruction in a state where the power consumption is reduced.

  When the signal indicating that the print instruction has been received from the instruction receiving unit 12 is input to the state determining unit 152 in the sleep state (YES in S15), the state determining unit 152 indicates that the state of the multifunction device 1 is It is determined that the startup is in the initial state, and a signal indicating the device state is sent to the switch control unit 153. In this case, the process returns to S3, and the switch control unit 153 switches (1) the capacitor charge / discharge switch 19 to the side for discharging the electric double layer capacitor 18, turns off the capacitor charge control circuit 20, and (2) The battery charge / discharge changeover switch 24 turns on the battery charge control circuit 25 on the side for charging the lithium ion battery 23 and (3) turns on the third fixing heater drive circuit 27 to drive the third fixing heater 26. Thereafter, the processes from S3 to S15 are repeated.

  If it is detected that the main switch 10 is turned off at any point in time from S3 to S15, the process returns to S1.

  In addition, this invention is not limited to the thing of the said embodiment, The aspect described below can be employ | adopted further. For example, in the above-described embodiment, the second fixing heater temperature detection unit 22 is described as including a thermistor. However, the second fixing heater temperature detection unit 22 is not limited to that including a thermistor. As long as the temperature of 21 can be detected, other elements, circuits, configurations, and the like may be used.

  In the above embodiment, the battery charge / discharge control circuit 24 is turned off in the print state, but the battery charge / discharge control circuit 24 may be turned on. In this case, the lithium ion battery 23 can be charged frequently.

  In the above embodiment, a DC current flows through the first fixing heater 17 and the second fixing heater 21 and an AC current flows through the third fixing heater 26. It is not limited to whether AC or DC is used for the current passed through the fixing heater.

  In each of the above embodiments, the electric double layer capacitor 18 is used as an auxiliary power source and the lithium ion battery 23 is used as a secondary battery. However, the electric double layer capacitor 18 or the lithium ion battery 23 is an auxiliary power source or a secondary battery. It is only an example of a battery and you may use another as an auxiliary power supply or a secondary battery.

  The configuration and processing shown in FIGS. 1 to 6 are merely one embodiment of the present invention, and the configuration and processing of the present invention are not limited thereto.

1 is a block diagram illustrating an internal configuration of a multifunction peripheral that is an embodiment of an image forming apparatus according to the present invention, and particularly a functional configuration centering on a fixing heater control mechanism that controls on / off of a fixing heater that heats a fixing roller; FIG. Each status type of the MFP (initial start-up state, late start-up state, print state, ready state, sleep state, and plug-in state) and the event type that triggers transition from each state to another state State transition information to be shown. It is a figure which shows the state of the capacitor charging / discharging switch, the capacitor charging control circuit, the battery charging / discharging switching switch, the battery charging control circuit, and the third fixing heater driving circuit in each state of the multifunction machine. It is a circuit diagram which shows the circuit image (outline) of a fixing heater control mechanism. 6 is a flowchart showing processing during driving of the fixing heater in the multifunction machine. 6 is a flowchart showing processing during driving of the fixing heater in the multifunction machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multifunction machine 2 External power supply 9 Power supply control circuit 10 Main switch 15 Control part 153 Switch control part 17 1st fixing heater 18 Electric double layer capacitor 19 Capacitor charge / discharge switching switch 20 Capacitor charge control circuit 21 2nd fixing heater 22 2nd fixing Heater temperature detection unit 23 Lithium ion battery 24 Battery charge / discharge switch 25 Battery charge control circuit 26 Third fixing heater 27 Third fixing heater drive circuit 30 Fixing heater

Claims (3)

A first auxiliary power source comprising a capacitor;
A second auxiliary power source comprising a secondary battery;
A first fixing heater that heats a fixing unit that fixes toner onto a recording sheet with electric power from the first auxiliary power source, and a second fixing heater that includes a halogen heater and heats the fixing unit with electric power from the second auxiliary power source A fixing heater having a third fixing heater that heats the fixing unit with electric power from an external power source;
First charge / discharge switching means for switching between discharging the first auxiliary power and supplying the first auxiliary power to the first fixing heater, or charging the first auxiliary power with power from an external power source;
Second charge / discharge switching means for switching whether to discharge the power of the second auxiliary power source and supply it to the second fixing heater, or to charge the second auxiliary power source with power from the external power source;
Third fixing heater driving means for switching whether or not to drive the third fixing heater with electric power from the external power source;
Temperature detecting means for detecting the temperature of the second fixing heater,
At the start of driving the fixing heater, the third fixing heater driving means drives the third fixing heater, switches the first charge / discharge switching means to the discharge side, drives the first fixing heater, and detects the temperature. When the temperature of the second fixing heater detected by the means rises to a temperature at which a rated current flows through the second fixing heater, the second charge / discharge switching means is switched to the discharge side to drive the second fixing heater. And an image forming apparatus.   The image forming apparatus according to claim 1, wherein the temperature detection unit includes a thermistor provided in the second fixing heater.   The control unit drives the third fixing heater by the third fixing heater driving unit and switches the first charge / discharge switching unit to the charging side when the recording paper is carried into the fixing unit. The image forming apparatus according to claim 1, wherein the fixing heater is stopped, and the second charge / discharge switching unit drives the second fixing heater as a discharge side.

Images