JP5434108B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to efficiency improvement of power saving of an image forming apparatus, and relates to efficiency improvement of power saving of an image forming apparatus such as a copying machine, a printer apparatus, and a facsimile apparatus using an electrophotographic system.

(Technical terms)
In this specification, the “off mode” means a state in which the power supply to the fixing member is stopped until the next operation (a) or (b) is performed (return to the next fixable state). The power supply to the fixing member is stopped).
(a) A user presses a power switch (not a main power switch) on the image forming apparatus main body to turn it on.
(b) An external signal such as an image formation start signal is input.

The “standby state” is a state in which the image forming apparatus is not performing an image forming operation and the fixing member is maintained at a predetermined temperature lower than a temperature at which the fixing member can be fixed, or the image forming apparatus Is a state in which the image forming operation is not being executed, and the power is not supplied from the main power supply device to the heating element of the fixing device. For example, the energy saving mode corresponds to an off mode in which the surface temperature of the fixing member is kept lower than the fixable temperature.
Further, “when returning” refers to the time when the surface temperature of the fixing member is raised to a predetermined temperature from the standby time.
Further, “when the main power switch is turned on” means when the temperature of the fixing member is raised immediately after the main power switch is turned on.
Further, “when starting up” means when returning or when the main power switch is turned on. “Start-up operation” refers to a preparatory operation necessary for image formation in the image forming apparatus from the time of return or when the main power switch is turned on. For example, an operation of heating the fixing member to a temperature at which the fixing member can be fixed (that is, paper can be passed) in the fixing device is included.
“Standby” refers to a state in which the temperature of the fixing member is maintained at a temperature at which paper can be passed, but no print command or print command is issued.
Also, “when paper is passed” means that the printing command or printing command is issued and the image forming operation is started until the recording medium is discharged out of the apparatus or until the discharge detection unit detects the discharge of the recording medium. Between. The “print command” refers to an instruction for image formation performed on the image forming apparatus from the operation panel of the image forming apparatus. The “print command” refers to an image formation instruction issued to the image forming apparatus from an information processing terminal (such as a PC) connected via a network.

  In recent years, environmental problems have become important and image forming apparatuses such as copiers and printers have been saving power. In order to save power in the image forming apparatus, it is effective to lower the temperature of a fixing member such as a fixing roller or a fixing belt of the fixing apparatus when the image forming apparatus is not passing paper (for example, during standby). However, if the temperature of the fixing member during non-sheet passing is lowered, when the fixing device is used, the temperature of the fixing member must be increased to a certain temperature at which fixing can be performed again. Have to wait. As a result, it takes time until the image forming apparatus is ready for use, and the usability of the image forming apparatus deteriorates.

In order to avoid this, there are the following two measures (1) and (2).
(1) Shortening the heating time of the heating means by assisting the power supply to the heating element of the heating means by supplying electric power from the auxiliary power supply (capacitor) to the heating element (capacitor heater) of the heating means. (For example, refer to Patent Document 1). By using this auxiliary power supply device to assist the power supply to the heating element of the heating means not only when the heating means is heated (when starting up or when returning from the off mode), but also when passing paper, power can be used more effectively. .
(2) The thickness of the fixing member (especially the fixing roller) is reduced as a configuration for quickly raising the temperature of the fixing member.

  Japanese Patent Application Laid-Open No. 2004-228688 discloses a constant magnification mode (a mode in which the output voltage of a capacitor is boosted at a constant magnification) in an image forming apparatus that supplies power to a heating element from an auxiliary power supply device via a boost circuit. And further changing the boosting magnification in the constant magnification mode based on the status information of the apparatus.

  As a result, the image forming apparatus can be started up in a short time from the standby state, but it is not yet sufficient. In addition, the power supply from the auxiliary power supply device is continued even when the paper is passed immediately after startup, but there is a possibility that fixing failure may occur due to a drop in temperature of the fixing member at the initial stage of paper feeding because the supplied power is small. It was.

  The present invention has been made in view of the above-described problems in the prior art, and is an image that improves the life of the power storage device by realizing both short-time startup from the standby state and prevention of fixing failure during paper feeding. An object is to provide a forming apparatus.

  When the inventor investigated the above-mentioned fixing failure at the initial stage of paper passing, when the fixing member was heated to a predetermined temperature in a short time, a capacitor was used at the time of paper passing and a thin fixing roller was used. As a result, when the sheet is started in this state, the fixing member and its peripheral parts are not sufficiently warmed, and the temperature drop of the fixing member at the time of passing the sheet is large, but the fixing member is fixed because the power supplied thereto is small. It was found that a fixing failure occurred because the necessary temperature was interrupted. Further, it has been found that there is room for improvement in starting the fixing device for a short time. Therefore, intensive studies were made to solve this problem, and the present invention was achieved.

That is, the present invention provided to solve the above problems is as follows.
[1] A main power supply (main power supply 9), an auxiliary power supply (auxiliary power supply 4b) having a chargeable / dischargeable power storage device, and a booster circuit (boost circuit 3) for boosting the output voltage of the auxiliary power supply A fixing member (fixing roller 14) , a pressure member (pressure roller 15) that contacts the fixing member to form a nip portion, and a main heater (main heating element 2a) to which electric power is supplied from the main power supply device And an auxiliary heater (auxiliary heating element 2b) to which electric power is supplied from the auxiliary power supply device via the booster circuit, and a fixing device (fixing apparatus) having heating means (heating element 2) for heating the fixing member 10), and the booster circuit supplies power to the heating unit from the main power supply device and the auxiliary power supply device via the booster circuit during the start-up operation of the image forming apparatus, From the auxiliary power supply It is controlled in a constant voltage mode for boosting the output voltage of the auxiliary power supply so that the power supplied to the heating means (auxiliary heating element 2b of the heating element 2) is constant, and when passing paper after the start-up operation, Control is performed in a constant magnification mode that boosts the output voltage of the auxiliary power supply device at a predetermined boosting magnification, and the constant magnification mode corresponds to the power supplied from the auxiliary power supply device at the start of supply corresponding to the rated power of the auxiliary heater. Selected from a plurality of modes such as a full power constant magnification mode for power consumption and a power saving constant magnification mode for power smaller than the rated power of the auxiliary heater, and paper feeding is started within a predetermined time from the start of the start-up operation. In the case where the full power constant magnification mode is selected as the constant magnification mode and paper feeding is started after a predetermined time has elapsed from the start of the start-up operation, the power saving constant magnification is selected as the constant magnification mode. When the image forming apparatus is selected and power is supplied to the heating unit only from the main power supply device during the start-up operation of the image forming apparatus, the booster circuit saves power when the paper is passed after the start-up operation. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled in a constant magnification mode (image forming apparatus 100, FIGS. 1 to 3, FIG. 5, FIGS. 9 to 11 , and FIG. 12 ) .
[2 ] In the case where continuous paper feeding is started after the start of the start-up operation within a predetermined time, the constant magnification mode control for the booster circuit is performed during the continuous paper feeding. The image according to [ 1 ], wherein the full power constant magnification mode is switched to the power saving constant magnification mode based on any one of temperature, the number of continuous sheets, and an elapsed time from the start of the start-up operation. Forming device (FIG. 6) .
[3 ] In the constant magnification mode, the boosting ratio of the boosting circuit is set to a predetermined scaling factor from the start of power supply from the auxiliary power supply device to a predetermined time, and thereafter is decreased stepwise or continuously. The image forming apparatus according to [1] or [2] (FIG. 7).
[ 4 ] An environmental temperature detection unit that detects an environmental temperature in the image forming apparatus is provided. When the temperature detected by the environmental temperature detection unit is equal to or higher than a predetermined temperature, the main power supply device and the booster are operated during the startup operation. The image forming apparatus according to any one of [1] to [ 3 ], wherein power is supplied to the heating unit from each of the auxiliary power supply devices via a circuit (FIG. 8).
[ 5 ] Power storage device voltage detection means for detecting a voltage value of the power storage device, and when the voltage value detected by the power storage device voltage detection means is a predetermined value or more, the main power supply device during the start-up operation, The image forming apparatus according to any one of [1] to [ 4 ], wherein power is supplied to the heating unit from each of the auxiliary power supply devices via a booster circuit (FIG. 8).
[ 6 ] The main power supply voltage detecting means for detecting the voltage value of the main power supply apparatus is provided, and when the voltage value detected by the main power supply voltage detection means is a predetermined value or more, the main power supply The image forming apparatus according to any one of [1] to [ 5 ], wherein power is supplied to the heating unit from each of the apparatus and the auxiliary power supply device via the booster circuit (FIG. 8).
[ 7 ] The image forming apparatus according to any one of [1] to [ 6 ], wherein the power storage device is a capacitor.

  According to the image forming apparatus of the present invention, since the booster circuit is controlled in the constant voltage mode during the start-up operation of the image forming apparatus, constant power is continuously supplied from the auxiliary power supply device to the heating unit via the booster circuit. It is possible to start up in a short time. Further, when the paper is passed, the mode is switched to the constant magnification mode, and electric power for suppressing the temperature drop of the fixing member is supplied at the start of paper feeding, so that fixing failure can be prevented. Further, as the constant magnification mode, there are a plurality of modes in which the power supplied from the auxiliary power supply device at the start of supply is different, and the number of times that the power storage device makes full output is reduced by appropriately using the mode. It becomes possible to improve the lifetime of the apparatus.

1 is a cross-sectional view illustrating a configuration example of an image forming apparatus according to the present invention. FIG. 2 is a schematic diagram illustrating a configuration of a fixing device. It is a circuit diagram of a heating system in the fixing device. It is a figure which shows the relationship between the auxiliary power supply output voltage in a constant voltage mode, a boost magnification, and a booster circuit output voltage. It is a figure which shows the relationship (1) of the auxiliary power supply output voltage in a fixed magnification mode, a step-up magnification, and a step-up circuit output voltage. It is a figure which shows the relationship (2) of the auxiliary power supply output voltage in a fixed magnification mode, a step-up magnification, and a step-up circuit output voltage. It is a figure which shows the example of the switching pattern of the step-up magnification of the step-up circuit in constant magnification mode. 6 is a flowchart illustrating processing from start-up operation of the image forming apparatus to printing operation. It is a figure which shows transition (1) of the temperature of the fixing roller in the case of a short time starting, and the discharge power of the electrical storage apparatus of an auxiliary power supply device. It is a figure which shows transition (2) of the temperature of the fixing roller in the case of a short time starting, and the discharge power of the electrical storage apparatus of an auxiliary power supply device. It is a figure which shows transition (3) of the temperature of the fixing roller in the case of a short time starting, and the discharge power of the electrical storage apparatus of an auxiliary power supply device. It is a figure which shows transition of the temperature of the fixing roller in the case of normal starting, and the discharge power of the electrical storage apparatus of an auxiliary power supply device.

The image forming apparatus according to the present invention will be described below.
<Overall configuration of image forming apparatus>
FIG. 1 is a cross-sectional view showing a configuration example of an image forming apparatus according to the present invention. The image forming apparatus 100 includes an automatic document feeder (ADF) 120 that sends a set original to be read to the reading device 130, a reading device 130 that reads the original sent from the ADF 120 as an image, and the reading device 130 reads the original. And an image forming unit 140 that forms an image based on the received image data.

  In FIG. 1, reference numeral 41 denotes a drum-shaped photoconductor which is an example of an image carrier made of a rotating body. Around the photosensitive member 41, a developing device including a charging device 42 composed of a charging roller, a mirror 43 constituting a part of an exposure unit, and a developing roller 44a in the order of rotation in the direction indicated by an arrow in the drawing. 44, a transfer device 48 for transferring the developed image onto a sheet (sheet) as the recording medium P, a cleaning device 46 provided with a blade 46a slidably contacting the peripheral surface of the photoreceptor 41, and the like. The photosensitive member 41 is exposed by being scanned with the exposure light Lb via the mirror 43 by the exposure unit between the charging device 42 and the developing roller 44a. The position irradiated with the exposure light Lb on the photoreceptor 41 is referred to as an exposure unit 150.

  The transfer device 48 is provided to face the lower surface of the photoreceptor 41. A portion of the photoconductor 41 facing the transfer device 48 is a transfer unit 47. A pair of registration rollers 49 is provided on the upstream side of the transfer portion 47 in the paper P conveyance direction. The recording medium P stored in a paper feed tray (not shown) is fed by a paper feed roller 110 and is transported and guided toward a registration roller 49 by a transport guide (not shown). Further, the fixing device 10 is disposed downstream of the transfer unit 47 in the paper P conveyance direction, and a paper discharge sensor 111 is provided in a paper discharge path on the nip portion exit side of the fixing device 10. The paper discharge sensor 111 detects the passage of the last sheet P of the print job through the nip portion and outputs a detection signal. The detection signal can detect the end of printing.

  Image formation in this image forming apparatus is performed as follows. The photosensitive member 41 is rotated by a driving unit (not shown) and starts rotating. During this rotation, the photosensitive member 41 is uniformly charged by the charging device 42 in the dark, and is exposed by the exposure light Lb through the mirror 43 by the exposure unit. By scanning 150, a latent image corresponding to the image to be created is formed on the photoreceptor 41. The latent image on the photoconductor 41 is moved to the developing device 44 by the rotation of the photoconductor 41, where it is developed by the developing device 44 to form a toner image.

  On the other hand, a sheet P as a recording medium on the sheet feeding tray is fed by the sheet feeding roller 110, and this sheet P is temporarily stopped at the position of the pair of registration rollers 49 through a conveyance path indicated by a broken line in the drawing. It waits for a delivery timing that matches the toner image on the body 41 with the transfer unit 47. At that timing, the registration roller 49 rotates and feeds the paper P, and the paper P is conveyed toward the transfer unit 47. The toner image on the photoconductor 41 and the paper P coincide with each other at the transfer unit 47, and the toner image on the photoconductor 41 is transferred onto the paper P by the electric field generated by the transfer device 48.

  In this way, the toner image is transferred and the paper P carrying the toner image is sent out to the fixing device 10. The toner image on the paper P is fixed on the paper P while passing through the fixing device 10, and the paper P on which the toner image is fixed is discharged to a paper discharge unit (not shown). On the other hand, the residual toner remaining on the photoconductor 41 without being transferred by the transfer unit 47 reaches the cleaning device 46 along with the rotation of the photoconductor 41 and is cleaned while passing through the cleaning device 46 to prepare for the next image formation. .

  As shown in FIG. 2, the fixing device 10 includes a fixing member and a pressure member, each of which is a cylindrical rotating body that is rotatably supported by an axis (axis in a direction perpendicular to the paper surface of FIG. 2A). Have The fixing member is composed of, for example, a fixing roller 14, and the pressure member is composed of, for example, a pressure roller 15. Inside the fixing roller 14, a heating element 2 that generates heat and heats the fixing roller 14 is disposed. Outside the fixing roller 14, a temperature detection unit 8 a that detects the surface temperature of the central portion of the fixing roller 14, and an end portion of the heating roller 2. Temperature detecting means 8b for detecting the surface temperature is arranged. In addition, a temperature detection means 8 c such as a thermistor for detecting the surface temperature of the pressure roller 15 is disposed outside the pressure roller 15.

  The main power supply device 9 in FIG. 1 supplies power to various units of each part of the image forming apparatus 100 with power from the commercial power supply 4a (see FIG. 3). The main power supply 9 is supplied with electric power from the commercial power supply 4a by inserting the plug 51 of the power line into the outlet (for example, 100V, 15A) of the commercial power supply 4a that is an external power supply. As shown in FIG. 2, the heating element 2 includes a heating element (also referred to as a main heating element or a main heater) 2a composed of an AC heater, and a heating element composed of a DC heater (an auxiliary heating element (also referred to as an auxiliary heater or a capacitor heater)). For example, a halogen heater is used. The main heating element 2a includes a main heating element (center heating element) 2a1 that mainly heats the central portion in the width direction of the fixing roller 14 and a main heating element (end portion heating) that heats the end of the fixing roller 14. Heating element) 2a2. The auxiliary heating element 2 b is a flat heater that heats the entire width of the fixing roller 14.

  Note that the total of the rated power of the central heating element 2a1, the fixing power of the end heating element 2a2, and the rated power of the auxiliary heating element 2b is 80% or more of the maximum power consumption of the AC power source consumed by the image forming apparatus 100. It is preferable to use a heater with a rated power such that In the case of the power of the external power source (commercial power source 4a) (in the case of Japan, 1500V of 100V15A), the maximum power consumption of the AC power source consumed by the image forming apparatus 100 is 1500W, so the total rated power of each heater is 1200W or more. become. Further, the sum of the rated power of the central heating element 2a1, the fixing power of the end heating element 2a2, and the rated power of the auxiliary heating element 2b is equal to or greater than the maximum power consumption of the AC power source consumed by the image forming apparatus 100. It is preferable to use a heater having a rated power. In this case, the total rated power of each heater is 1500 W or more.

  The roller base of the fixing roller 14 is preferably made of a metal such as aluminum or iron from the viewpoint of durability, deformation due to pressure, or the like. The thickness of the roller base at this time is thin because the fixing roller 14 is rapidly heated when the apparatus is started up and reaches a predetermined temperature in a short time, and is preferably less than 5 mm and preferably 1 mm or less. More preferred. For example, it is 0.7 mm. Further, it is desirable to form a release layer on the surface of the fixing roller 14 to prevent the toner from adhering. The inner surface of the fixing roller 14 efficiently absorbs the radiant heat of the heating element 2 that is a halogen heater. It is desirable that the blackening process is performed. Of course, a fixing belt or the like may be used instead of the fixing roller 14 or in combination with the fixing roller 14.

  The pressure roller 15 forms a nip portion with the fixing roller 14 by forming an elastic layer such as rubber on the core metal, and a recording medium P such as paper on which an unfixed image is formed in the nip portion. By passing the paper, the toner image is fixed on the recording medium P by heat and pressure. In addition, the outer diameter of the pressure roller 15 of this embodiment is 40 mm. Further, a nip portion may be formed between the pressure roller 15 and the fixing roller 14 by using a pressure roller having a foam layer as the pressure roller 15. In this case, the heat of the fixing roller 14 is not easily transmitted to the pressure roller 15 due to the heat insulating effect of the foam layer, so that the temperature of the fixing roller 14 can be increased quickly. Of course, a pressure belt or the like may be used instead of the pressure roller 15 or in combination with the pressure roller 15.

  Here, the cpm (Copies Per Minute) of the image forming apparatus 100 is preferably 60 sheets or more. The cpm of the image forming apparatus 100 of the present embodiment is as high as 75 (linear speed 360 mm / s), and the startup time is shortened (about 10 seconds) as will be described later.

<Circuit configuration of fixing device>
FIG. 3 shows a circuit configuration for operating the fixing device 10. In the present embodiment, an electric double layer capacitor (electric double layer capacitor) is used as the power storage device included in the auxiliary power supply device 4b, and the booster circuit 3 that boosts the output voltage of the electric double layer capacitor is provided.

  As shown in FIG. 3, a circuit for operating the fixing device 10 mainly includes a main power supply device 9 that supplies power using a commercial power supply 4 a, an auxiliary power supply device 4 b that includes, for example, a plurality of capacitor cells, A charging device 5 that performs voltage adjustment and AC / DC conversion of power supplied from the main power supply device 9 and supplies DC power after AC / DC conversion to the auxiliary power supply device 4b to charge the auxiliary power supply device 4b; A booster circuit 3 that boosts the output voltage of the power supply device 4b; and a heating element 2 (main heating element 2a, auxiliary heating element 2b) that is a heating means that generates heat by power supplied from the main power supply device 9 and the auxiliary power supply device 4b. The main heating element 2a is supplied with power from the commercial power source 4a when the switch 6 is energized, and the auxiliary heating element 2b is connected via the booster circuit 3 when the switch 7 is energized. Auxiliary power It arrange | positions on a circuit so that electric power may be supplied from the source device 4b and it may generate | occur | produce.

  The heating element 2 is, for example, a halogen heater that has a long life due to the halogen cycle and can generate heat with high efficiency. A heating wire in the glass tube emits light by supplying electric power to heat the fixing roller 14.

  The main heating element 2a is connected to the main power supply device 9 which is 100 (V) in Japan, and the resistance value varies depending on the required power depending on the function and performance of the image forming apparatus 100. For example, in the image forming apparatus 100 that requires 120 (W), the resistance value of the main heating element 2a is about 8 (Ω), and in the image forming apparatus 100 that requires 700 (W), about 14 ( Ω). The main heating element 2a and the auxiliary heating element 2b can be independently turned on / off (energization controlled) by the switch 6 and the switch 7.

  The auxiliary power supply 4b stores the electric power supplied from the commercial power supply 4a by the charging device 5, boosts the voltage of the stored electric power (output voltage of the auxiliary power supply 4b) by the booster circuit 3, and turns on the switch 7 ( In the energized state, power is supplied to the auxiliary heating element 2b.

  The power storage device in the auxiliary power supply 4b is a chargeable / dischargeable power supply and uses an electric double layer capacitor that is a capacitor that can be easily increased in capacity. The discharge characteristics of the auxiliary power supply device 4b using the electric double layer capacitor are as follows. When the electric double layer capacitor is sufficiently charged, the output voltage is high (supplying large power) at the beginning of discharge, and the discharge time. At the same time, the output voltage decreases (power decreases). Then, in the process of discharging, the electric double layer capacitor has almost no remaining power, reaches a voltage at which it hardly discharges (discharge stop voltage), and the discharge (power supply) as the auxiliary power supply device 4b is stopped. In this state, the electric double layer capacitor is charged by the charging device 5 at least until it reaches a dischargeable voltage. The dischargeable voltage is a voltage at the boundary between a voltage having a power for heating the fixing roller 14 and a voltage having no power until the fixing roller 14 is heated at the stage of starting the discharge. If it is less, the voltage is not discharged.

Here, unlike the secondary battery, the capacitor does not involve a chemical reaction and thus has the following excellent characteristics.
・ Short charging time With an auxiliary power source using a nickel-cadmium battery, which is a general secondary battery, it takes several hours even if quick charging is performed. It can only be realized a few times and is not practical. In contrast, an auxiliary power source using a capacitor can be rapidly charged for several tens of seconds to several minutes, so that the number of times of heating using the auxiliary power source can be increased to a practical number.
・ Long service life The nickel-cadmium battery has 500 to 1000 charge / discharge cycles, so it has a short life as an auxiliary power source for the purpose of supplying large power such as heating. Become. On the other hand, an auxiliary power source using a capacitor has a life of 10,000 times or more and is less deteriorated by repeated charge and discharge. Further, unlike lead-acid batteries, there is no need for liquid replacement or replenishment, so only limited maintenance work is required.

  In the present embodiment, a plurality of capacitors having such characteristics are provided as shown in FIG. For example, the auxiliary power supply device 4b having a configuration in which ten capacitor cells having a capacitance of 2000 (F) and an internal resistance of 3 m (Ω) are connected in series is used. Since the rated voltage of the capacitor cell is 2.5 (V), when all the cells (10 cells) are combined, the rated voltage is 25 (V).

  Although not shown in detail, it is necessary to provide a circuit that detects the voltage of each capacitor cell and bypasses the charging current and discharging current so as not to overcharge and overdischarge in order to ensure long-term reliability. Is desirable. The capacitor to be used is not limited to the electric double layer capacitor, and the auxiliary power supply device 4b composed of a plurality of capacitor cells includes an electric double layer capacitor, a non-activated carbon electrode capacitor, a lithium ion capacitor, a pseudo capacitance capacitor, A different type of capacitor such as a hybrid capacitor may be combined.

  The switch 6 as the connection means is controlled by a first control unit (not shown) as control means for controlling energization to the main heating element 2a. The first control unit is supplied with power from the main power supply device 9 regardless of whether the main power switch of the image forming apparatus 100 is on or off, and from a main control unit (not shown) that controls each part of the image forming apparatus 100. Based on the mode signal, the temperature detection signal from the temperature detection means 8, and the like, the switch 6 is controlled so that the surface temperature of the fixing roller 14 and the pressure roller 15 becomes a set temperature at which fixing is possible.

  The switch 7 as the connection means is controlled by a second control unit (not shown) as a control means for controlling energization to the auxiliary heating element 2b. The second control unit is supplied with power from the main power supply unit 9 regardless of whether the main power switch of the image forming apparatus 100 is on or off, and receives a mode signal from the main control unit, a temperature detection signal from the temperature detection means 8, and an auxiliary unit. The energization from the auxiliary power supply 4b to the auxiliary heating element 2b is controlled based on the output value of the electric energy detection means for detecting the electric energy (voltage) of the power supply 4b.

  With such a circuit configuration, the fixing device 10 according to the present embodiment supplies power from the commercial power supply 4a (main power supply device 9) to the main heating unit 2a as shown in FIG. Power is supplied to the auxiliary heating element 2b from the auxiliary power supply 4b via the booster circuit 3, and the electric power from both the main power supply 9 and the auxiliary power supply 4b is simultaneously supplied to the heating element 2. By supplying, the electric power exceeding the electric power supplied only by the main power supply device 9 can be supplied to the heating element 2.

  That is, in this embodiment, at the time of start-up, the temperature of the fixing roller 14 can be raised in a short time by the power supplied from the main power supply device 9 and the power supplied according to the initial discharge characteristics of the electric double layer capacitor (short-time start-up). Called up). Further, the temperature of the fixing roller 14 by the main heating element 2a supplied with power from the commercial power source 4a is assisted by the temperature of the fixing roller 14 by the auxiliary heating element 2b when the paper is passed to maintain the temperature of the fixing roller 14. Is possible. In this embodiment, the temperature of the fixing roller 14 may be raised only by the power supplied from the main power supply device 9 during startup (referred to as normal startup). In addition, the auxiliary power supply 4b is charged in a state where the power supply from the main power supply 9 to each part of the image forming apparatus is low, for example, during standby.

<Control mode of booster circuit>
In the present invention, by controlling the boosting factor of the booster circuit 3 that boosts the output voltage of the auxiliary power supply device 4b (power storage device) disposed between the auxiliary power supply device 4b and the heating element 2 (auxiliary heating element 2b). And a plurality of modes for controlling the power supplied from the auxiliary power supply device 4b to the heating element 2 (auxiliary heating element 2b). The contents of each mode will be described below.

(1) Constant voltage mode In this mode, the boost voltage of the booster circuit 3 is adjusted to boost the output voltage of the auxiliary power supply 4b so that the power supplied from the auxiliary power supply 4b to the heating element 2 is constant. This mode is applied, for example, when the image forming apparatus 100 is started up.

FIG. 4 is a diagram showing the relationship among the auxiliary power supply output voltage, the boost ratio, and the booster circuit output voltage in the constant voltage mode.
In the image forming apparatus 100, in order to complete the start-up operation in a short time from the start-up, the output voltage of the booster circuit 3, that is, the heating element 2 (auxiliary heating element 2b from the auxiliary power supply 4b via the booster circuit 3). ) Is increased as much as possible, as shown in FIG. 4B, the boost ratio is changed so as to gradually increase from the start of power supply. As a result, as shown in FIG. 4C, a constant output voltage is generated from the start to the end of power supply, and constant power is supplied to the heating element 2 (auxiliary heating element 2b). Accordingly, as shown in FIG. 4A, the discharge voltage of the auxiliary power supply device 4b (power storage device) decreases with time.

  In this constant voltage mode, the power supplied from the auxiliary power supply device 4b to the heating element 2 (auxiliary heating element 2b) via the booster circuit 3 is constant power corresponding to the rated power of the auxiliary heater (auxiliary heating element 2b). Preferably there is. This rated power is, for example, 60V and 800W.

(2) Constant magnification mode In this mode, the output voltage of the auxiliary power supply device 4b is boosted by setting the boosting factor of the booster circuit 3 to a predetermined factor. This mode is applied, for example, when a sheet is passed after the start-up operation of the image forming apparatus 100.

FIG. 5 is a diagram showing a relationship (1) among the auxiliary power supply output voltage, the boosting magnification, and the boosting circuit output voltage in the constant magnification mode.
First, as shown by the solid line in FIG. 5B, the boosting magnification is set to a predetermined magnification b from the start of power supply. As a result, as shown by the solid line in FIG. 5C, a predetermined output voltage is generated at the start of power supply, and predetermined power is supplied to the heating element 2 (auxiliary heating element 2b). Thereafter, the boost ratio is kept constant, but the output voltage of the booster circuit 3 tends to gradually decrease with time (FIG. 5 (c)).

  Here, the constant magnification mode is a full power constant magnification mode in which the power supplied from the auxiliary power supply device 4b at the start of supply is equal to the rated power of the auxiliary heater (auxiliary heating element 2b). It is preferable to select from a plurality of modes of a power saving constant magnification mode in which the power is smaller than the rated power of the heating element 2b).

  In FIG. 5, the full power constant magnification mode is a mode indicated by a broken line. For example, in the image forming apparatus 100, the paper is started within a predetermined time from the start of the start-up operation in the case of the short-time start-up. This is the mode that is sometimes selected. On the other hand, the power-saving constant magnification mode is a mode indicated by a solid line, and is the case of the short-time startup, when the paper is started after a predetermined time has elapsed from the start of the startup operation, or after the normal startup. This mode is selected when the paper starts.

In the full power constant magnification mode, as shown by the broken line in FIG. As a result, a high output voltage is generated as indicated by the broken line in FIG. 5C, and a large amount of power is supplied to the auxiliary heater (auxiliary heating element 2b). Note that the power supplied from the auxiliary power supply 4b at the start of supply is equivalent to the rated power (for example, 60V, 800W) of the auxiliary heater (auxiliary heating element 2b). Further, as shown by a broken line in FIG. 5A, the time (discharge time) until the output voltage of the auxiliary power supply device 4b (power storage device) decreases to a constant voltage is set when a low boosting factor b is set ( (Δt ₂ <Δt ₁ ).

On the other hand, the power saving constant magnification mode is set to a low step-up magnification b as shown by the solid line in FIG. Thereby, a low output voltage is generated as shown by the solid line in FIG. 5C, and less power is supplied to the auxiliary heater (auxiliary heating element 2b) than in the full power constant magnification mode. Note that the power supplied from the auxiliary power supply device 4b at the start of supply is lower than the rated power (eg, 60V, 800W) of the auxiliary heater (auxiliary heating element 2b) (eg, 500W). Further, as shown by the solid line in FIG. 5A, the time (discharge time) until the output voltage of the auxiliary power supply device 4b (power storage device) decreases to a certain voltage is set when a high boosting factor a is set ( (Δt ₂ <Δt ₁ ).

FIG. 6 is a diagram showing a relationship (2) among the auxiliary power supply output voltage, the boosting magnification, and the boosting circuit output voltage in the constant magnification mode.
In the present invention, as the constant magnification mode, the boosting ratio of the boosting circuit 3 is set to a predetermined ratio from the start of power supply from the auxiliary power supply device 4b to a predetermined time, and thereafter is decreased stepwise or continuously. Also good. Thereby, it is possible to extend the discharge time of the auxiliary power supply device 4b (power storage device) while preventing the fixing failure.

  FIG. 6 shows an example in which a predetermined magnification is set from the start of power supply from the auxiliary power supply device 4b to a predetermined time, and thereafter is decreased by one step. Here, the constant magnification mode control for the booster circuit 3 is fully controlled. Switching from the power constant magnification mode to the power saving constant magnification mode is performed. For example, this switching is performed during the short-time startup, and when continuous paper feeding is started within a predetermined time from the start of the startup operation, the pressurizing member ( This may be performed when the pressure roller 15) is equal to or more than a set threshold value based on any one of the temperature of the pressure roller 15), the set number of continuous sheets, and the elapsed time from the start of the start-up operation.

  In FIG. 7, as a constant magnification mode, the boosting factor of the booster circuit 3 is set to a predetermined factor from the start of power supply from the auxiliary power supply device 4b to a predetermined time, and thereafter is decreased stepwise or continuously (switched). It is a figure which shows the example of a pattern.

  In the present invention, the step-up ratio as shown in FIG. 7 is set to a predetermined ratio from the start of power supply to a predetermined time, and thereafter, switching patterns 1 to 3 that are changed (switched) stepwise and switching patterns that are changed continuously. 4 is preferably converted into data, and the data is stored in a nonvolatile storage device included in the fixing device 10 or the image forming apparatus 100 in association with an assumed combination of device states. . In the switching pattern 4, the power is continuously changed after the predetermined magnification is set for a very short time from the start of power supply.

  Thus, the booster circuit 3 is controlled based on the data of the boosting magnification switching pattern stored in the storage device in association with the combination of the corresponding device states depending on the device states of the fixing device 10 and / or the image forming device 100. The power supplied from the auxiliary power supply 4b to the heating element 2 (auxiliary heating element 2b) can be controlled according to the apparatus state of the fixing device 10 and / or the image forming apparatus 100. Further, by adopting a configuration having a plurality of boosting magnification settings of the booster circuit 3, it is possible to reduce excess power consumption and maintain stable mechanical performance.

<Operation of Image Processing Device>
(1) Startup Operation to Image Forming Operation The image forming apparatus 100 according to the present embodiment detects the environmental temperature detecting means for detecting the environmental temperature inside or outside the apparatus, and the voltage value of the power storage device (auxiliary power supply device 4b). It is preferable to include at least one of a power storage device voltage detection means and a main power supply device detection means for detecting the voltage value of the main power supply device 9. The environmental temperature detection means, the power storage device voltage detection means, and the main power supply device detection means are not particularly limited as long as they are configured by, for example, known or new sensors.

  Hereinafter, processing from the start-up operation of the image forming apparatus 100 to the printing operation (image forming operation) will be described with reference to the flowchart shown in FIG. First, when the power key is turned on (S1), it is determined whether or not the environmental temperature T1 detected by the environmental temperature detection means is equal to or higher than a predetermined temperature (indicated by t) (S2). (S2: No), the start-up operation is executed only by supplying power from the main power supply device 9 to the main heating element 2a (S6). This is because the environmental temperature T1 can be regarded as the temperature of the recording medium and components, and if this is too low, it is difficult to complete the startup within the scheduled time in a short startup.

  On the other hand, if the temperature is equal to or higher than the predetermined temperature (S2: Yes), it is next determined whether or not the voltage value V2 of the auxiliary power supply device 4b is equal to or higher than a predetermined voltage (indicated by vb) (S3). If it is less than the predetermined voltage (S3: No), the startup operation (normal startup operation) is executed only by supplying power from the main power supply device 9 to the main heating element 2a (S6). The predetermined voltage vb is, for example, a dischargeable voltage of the auxiliary power supply device 4b.

  On the other hand, when the voltage is equal to or higher than the predetermined voltage (S3: Yes), it is next determined whether or not the voltage value V1 of the main power supply device 9 is equal to or higher than the predetermined voltage (indicated by va) (S4). If it is less than the predetermined voltage (S4: No), the start-up operation is executed only by supplying power from the main power supply device 9 to the main heating element 2a (S6). This is because if the voltage value V1 of the main power supply device 9 is low, the heat generation amount of the heat generating element 2 (main heat generating element 2a) decreases, and it is difficult to complete the start-up within the scheduled time for a short start-up.

  On the other hand, when the voltage is equal to or higher than the predetermined voltage (S4: Yes), power is supplied from the main power supply device 9 and the auxiliary power supply device 4b to the main heating element 2a and the auxiliary heating element 2b, and the start-up operation (short-time start-up operation) is performed. It is executed (S5).

  As described above, when any one of the above conditions (environment temperature, charging voltage of the auxiliary power supply 4b, voltage of the main power supply 9) is less than a predetermined value, the auxiliary power supply 4b is started when the image forming apparatus 100 is started up. Thus, the auxiliary heating element 2b is not supplied with power, and the normal start-up operation is executed only by supplying power from the main power supply 9 to the main heating element 2a (S6).

  In contrast, when the image forming apparatus 100 is started up, the environmental temperature inside or outside the apparatus is equal to or higher than a predetermined temperature, the charging voltage value of the auxiliary power supply 4b is equal to or higher than a predetermined value, and the main power supply 9 Is greater than or equal to a predetermined value, power is supplied from the main power supply device 9 and the auxiliary power supply device 4b to the main heating element 2a and the auxiliary heating element 2b, and a start-up operation is executed for a short time (S5).

  Note that the fixing roller 14 and the pressure roller 15 are not rotated in both cases of a short-time startup and a normal startup.

  Further, the image forming apparatus 100 of the present embodiment includes an environmental temperature detection unit, a power storage device voltage detection unit, and a main power supply device detection unit, and from the auxiliary power supply device 4b to the auxiliary heating element 2b during startup based on the above three conditions. However, the present invention is not limited to this. For example, one or two of the three may be combined and controlled.

  When the fixing roller 14 reaches a predetermined temperature by the start-up operation (S5, S6) of either of the two patterns, a printing command from the operation panel or the like of the image forming apparatus 100, or an information processing terminal connected via a network It becomes a standby time in which the fixing roller 14 is maintained at a predetermined temperature until a print command or the like is issued from a PC or the like.

  In the standby time, the temperature of the fixing roller 14 is maintained at a predetermined temperature by the power from the main power supply device 9, and the auxiliary power supply device 4 b is charged from the main power supply device 9 through the charging device 5. When a print command or a print command is received in this state, an image forming operation is started (during paper feeding).

  In the present embodiment, when the paper is passed, power is supplied from the main power supply 9 to the main heating element 2a, and power is supplied from the auxiliary power supply 4b to the auxiliary heating element 2b, so that the temperature of the fixing roller 14 is maintained. It has come to be. For example, when the start-up operation is performed by receiving a print request from the PC and executing the start-up, the fixing roller 14 reaches a predetermined temperature by the start-up operation. Then, the image forming operation is started immediately.

  When the paper feeding is completed, the standby mode is entered again, and the auxiliary power supply 4b is charged until the next print command or print command is received. When there is no print command or print command for a predetermined time, the standby mode is shifted to an energy saving mode such as an off mode. In the energy saving mode, when a print command is issued, when a sheet is placed on the ADF, or when a panel operation of the operation panel is executed, a startup operation is executed. This is repeated thereafter.

(2) Booster Circuit Control In the image forming apparatus according to the present invention, in the image forming apparatus 100, when the booster circuit 3 starts up the image forming apparatus 100, the auxiliary power supply via the main power supply device 9 and the booster circuit 3 is used. When electric power is supplied from each of the devices 4b to the heating means (heating element 2), the auxiliary power supply 4b has a constant power supply from the auxiliary power supply 4b to the heating means (auxiliary heating element 2b). It is controlled in a constant voltage mode for boosting the output voltage, and is controlled in a constant magnification mode for boosting the output voltage of the auxiliary power supply device 4b at a predetermined boosting factor when the paper is passed after the start-up operation. Is.
Hereinafter, the control of the booster circuit 3 that the present invention can take will be described by way of examples. Here, continuous paper feeding is assumed.

(Quick startup 1)
FIG. 9 is a diagram showing the transition (1) of the temperature of the fixing roller and the discharge power of the power storage device (capacitor) of the auxiliary power supply device 4b in the case of short startup. Here, for example, a case where a print command for continuous printing is issued from the information processing terminal (PC) to the image forming apparatus 100 via a network is shown.
(I) Startup First, power is supplied from both the main power supply device 9 and the auxiliary power supply device 4b, and the startup operation is executed (corresponding to S5 in FIG. 8). At this time, the booster circuit 3 is controlled in the constant voltage mode, and constant power is supplied from the auxiliary power supply device 4b to the auxiliary heating element 2b during the startup period. For example, the boosting magnification is adjusted so that the output voltage of the booster circuit 3 is 60 V, and 800 W corresponding to the rated power of the auxiliary heating element 2 b is supplied to the auxiliary heating element 2 b. As a result, the fixing roller 14 is rapidly heated, and the fixing roller temperature rises to a predetermined temperature in 10 seconds from the start-up.

(Ii) Paper feed (continuous paper feed)
Since the print command has been issued, the recording medium is conveyed to the fixing device 10 immediately after the start-up is completed, and the paper feeding is started. Immediately after the start of paper feeding, the heat of the fixing roller 14 is lost due to the contact of the heating roller 15 or the like, so that the temperature of the fixing roller tends to decrease once. At this time, due to the startup in a short time, the supporting parts of the fixing roller 14, the pressure roller 15, and peripheral parts are not warmed up (not stored), and the fixing roller is deprived of heat. Since the temperature of 14 is particularly greatly reduced, it is necessary to prevent fixing failure by supplying as much power as possible from the main power supply device 9 and the auxiliary power supply device 4b. Therefore, the booster circuit 3 is controlled in the full power constant magnification mode so that the power supplied from the auxiliary power supply device 4b at the start of supply becomes power (for example, 60V, 800W) corresponding to the rated power of the auxiliary heating element 2b. The boosting magnification is Then, the boosting factor of the booster circuit 3 is preferably set to this factor from the start of power supply to a certain time, and then gradually reduced. Table 1 shows the change in the step-up magnification at this time.

  By controlling the booster circuit 3 as described above, it is possible to start up for a short time and to prevent fixing failure after the start of paper feeding (particularly immediately after the start of paper feeding). In addition, since the subsequent step-up magnification is decreased stepwise, it is possible to cope with continuous continuous paper feeding for a long time. Furthermore, the deterioration of the power storage device (capacitor) in the auxiliary power supply device 4b can be suppressed, and the life can be extended.

  The predetermined time here is, for example, 30 seconds from the start of startup. In other words, when the power is supplied from the auxiliary power supply 4b to the auxiliary heating element 2b in the image forming apparatus and the power is supplied from the main power supply 9 to the main heating element 2a, the time required for the start-up operation is 10 seconds. If there is, it is 20 seconds from the start-up completion (the same applies hereinafter).

  In addition, after starting the full power constant magnification mode control for the booster circuit 3 when the paper is passed, the supporting parts of the fixing roller 14, the pressure roller 15 and peripheral parts are sufficiently warmed, and the fixing failure due to the temperature drop of the fixing roller 14 When it is determined that there is no longer the possibility, the full power constant magnification mode may be switched to the power saving constant magnification mode as shown in FIG. The switching determination is made based on any of the temperature of the pressure member (pressure roller 15), the set number of continuous sheets, and the elapsed time (for example, 30 seconds) from the start of the start-up operation. Good.

(Short startup 2)
FIG. 10 is a diagram showing the transition (2) of the temperature of the fixing roller and the discharge power of the power storage device (capacitor) of the auxiliary power supply device 4b in the case of short startup. Here, a case is shown in which the standby state is entered after the start-up is completed, and the paper feeding starts within a predetermined time from the start of the start-up.
(I) Start-up As in the case of short-time start-up 1, first, power is supplied from both the main power supply device 9 and the auxiliary power supply device 4b, and the start-up operation is executed (corresponding to S5 in FIG. 8). At this time, the booster circuit 3 is controlled in the constant voltage mode, and constant power is supplied from the auxiliary power supply device 4b to the auxiliary heating element 2b during the startup period. As a result, the fixing roller 14 is rapidly heated, and the fixing roller temperature rises to a predetermined temperature in 10 seconds from the start-up.

(Ii) Standby After the start-up is completed, the standby state is entered, and the roller temperature of the fixing roller 14 is maintained at a certain temperature or higher. During this time, the auxiliary power supply 4b is charged, and the fixing roller 14 and the pressure roller 15 are not rotated.

(Iii) Paper feed (continuous paper feed)
Within a predetermined time from the start of the start-up operation, the image forming apparatus 100 has a print command or a print command, and the recording medium is conveyed to the fixing device 10 and paper feeding is started. Immediately after the start of paper passing, the temperature of the fixing roller 14 decreases particularly as in the case of the short startup 1 so that as much power as possible is supplied from the main power supply device 9 and the auxiliary power supply device 4b to prevent fixing failure. There is a need to prevent. Therefore, the booster circuit 3 is controlled in the full power constant magnification mode according to the magnification shown in Table 1.

  By controlling the booster circuit 3 as described above, it is possible to start up for a short time and to prevent fixing failure after the start of paper feeding (particularly immediately after the start of paper feeding). In addition, since the subsequent step-up magnification is decreased stepwise, it is possible to cope with continuous continuous paper feeding for a long time. Furthermore, the deterioration of the power storage device (capacitor) in the auxiliary power supply device 4b can be suppressed, and the life can be extended.

(Short startup 3)
FIG. 11 is a diagram showing a transition (3) of the temperature of the fixing roller and the discharge power of the power storage device (capacitor) of the auxiliary power supply device 4b in the case of short startup. Here, a case is shown in which the standby state is entered after the start-up is completed, and the sheet passing is started after a predetermined time has elapsed from the start of the start-up.
(I) Start-up As in the case of the short-time start-ups 1 and 2, first, power is supplied from both the main power supply device 9 and the auxiliary power supply device 4b to execute the start-up operation (corresponding to S5 in FIG. 8). . At this time, the booster circuit 3 is controlled in the constant voltage mode, and constant power is supplied from the auxiliary power supply device 4b to the auxiliary heating element 2b during the startup period. As a result, the fixing roller 14 is rapidly heated, and the fixing roller temperature rises to a predetermined temperature in 10 seconds from the start-up.

(Ii) Standby After the start-up is completed, the standby state is entered, and the roller temperature of the fixing roller 14 is maintained at a certain temperature or higher. During this time, the auxiliary power supply 4b is charged, and the fixing roller 14 and the pressure roller 15 are not rotated.

(Iii) Paper feed (continuous paper feed)
After a predetermined time (for example, 30 seconds) has elapsed since the start of the start-up operation, the image forming apparatus 100 has a print command or a print command, and the recording medium is conveyed to the fixing device 10 and paper feeding is started. Immediately after the start of paper feeding, the temperature of the fixing roller tends to decrease. However, since a predetermined time has elapsed since the start of the start-up operation, the supporting parts of the fixing roller 14, the pressure roller 15, and peripheral parts are sufficiently warmed. The temperature of the fixing roller 14 does not decrease as in the case of the first and second startups. Therefore, the booster circuit 3 is controlled in the power saving constant magnification mode so that the power supplied from the auxiliary power supply device 4b at the start of supply is lower than the rated power of the auxiliary heating element 2b (for example, 500 W). Magnification. Then, the boosting factor of the booster circuit 3 is preferably set to this factor from the start of power supply to a certain time, and then gradually reduced. Table 2 shows the change in the step-up magnification at this time.

  By controlling the booster circuit 3 as described above, it is possible to start up for a short time and to support continuous paper feeding for a long time. Furthermore, the deterioration of the power storage device (capacitor) in the auxiliary power supply device 4b can be suppressed, and the life can be extended. Although the power supplied from the auxiliary power supply 4b at the start of power supply in the power saving constant magnification mode is 500 W here, it may be changed according to the set number of continuous sheets. For example, when about 5 sheets are continuously passed, the power supplied from the auxiliary power supply 4b at the start of supply is set to 100 W, and when about 1000 sheets are continuously passed, the auxiliary power supply 4b at the start of supply is supplied. The power supplied from is set to 500W.

(Normal startup)
FIG. 12 is a diagram showing transitions of the temperature of the fixing roller and the discharge power of the power storage device (capacitor) of the auxiliary power supply device 4b in the case of normal startup. Here, a case where paper feeding starts after completion of normal startup is shown.
(I) Startup First, power is supplied only from the main power supply device 9 and the startup operation is executed (corresponding to S6 in FIG. 8). As a result, the fixing roller 14 is heated over a predetermined time (for example, 30 seconds), and the fixing roller temperature rises to a predetermined temperature.

(Ii) Standby After the start-up is completed, the standby state is entered, and the roller temperature of the fixing roller 14 is maintained at a certain temperature or higher. During this time, the auxiliary power supply 4b is charged, and the fixing roller 14 and the pressure roller 15 are not rotated.

(Iii) Paper feed (continuous paper feed)
After the start-up operation is completed, the image forming apparatus 100 has a print command or a print command, and the recording medium is conveyed to the fixing device 10 and paper feeding is started. Immediately after the start of paper feeding, the temperature of the fixing roller tends to decrease. However, since a predetermined time has elapsed since the start of the start-up operation, the supporting parts of the fixing roller 14, the pressure roller 15, and peripheral parts are sufficiently warmed. The temperature of the fixing roller 14 does not decrease as in the case of the first and second startups. Therefore, the booster circuit 3 is controlled in the power saving constant magnification mode according to Table 2.
By controlling the booster circuit 3 as described above, it is possible to cope with continuous paper feeding for a long time.

  Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, modifications, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

2, 2a, 2b, 2a1, 2a2 Heating element (heating means)
3 Booster circuit 4a Commercial power supply (main power supply)
4b Auxiliary power supply device 5 Charging device 6, 7 Switch 8, 8a, 8b, 8c Temperature detection means 9 Main power supply device 10 Fixing device 14 Fixing roller 15 Pressure roller 41 Photoconductor 42 Charging device 43 Mirror 44 Developing device 44a Developing roller 46 Cleaning device 46a Blade 47 Transfer section 48 Transfer device 49 Registration roller 51 Plug 100 Image forming device 110 Paper feed roller 111 Paper discharge sensor 120 ADF (automatic document feeder)
DESCRIPTION OF SYMBOLS 130 Reader 140 Image forming part 150 Exposure part Lb Exposure light P Sheet (recording medium)

JP 2000-315567 A JP 2008-275994 A

Claims (7)

A main power supply;
An auxiliary power supply device having a chargeable / dischargeable power storage device;
A booster circuit for boosting the output voltage of the auxiliary power supply device;
A fixing member , a pressure member that forms a nip portion in contact with the fixing member , a main heater that is supplied with electric power from the main power supply device, and an auxiliary heater that is supplied with electric power from an auxiliary power supply device via the boosting circuit And a fixing device having a heating means for heating the fixing member,
The booster circuit includes:
In the start-up operation of the image forming apparatus, when power is supplied to the heating unit from the main power unit and the auxiliary power unit via the booster circuit, the power supplied from the auxiliary power unit to the heating unit is It is controlled in a constant voltage mode for boosting the output voltage of the auxiliary power supply so that it is constant,
Controlled in a constant magnification mode for boosting the output voltage of the auxiliary power supply device at a predetermined boosting magnification at the time of passing the paper after the start-up operation ,
The constant power mode is a full power constant power mode in which the power supplied from the auxiliary power supply device at the start of supply is a power corresponding to the rated power of the auxiliary heater, and a power smaller than the rated power of the auxiliary heater. It is selected from multiple modes of power saving constant magnification mode,
When paper feeding is started within a predetermined time from the start of the start-up operation, the full power constant magnification mode is selected as the constant magnification mode,
When paper feeding is started after a lapse of a predetermined time from the start of the start-up operation, a power saving constant magnification mode is selected as the constant magnification mode,
When power is supplied to the heating unit only from the main power supply device during the start-up operation of the image forming apparatus, the booster circuit is controlled in a power-saving constant magnification mode during paper feeding after the start-up operation. images forming device you characterized by that. In the case of continuously passing paper after starting to pass within a predetermined time from the start of the start-up operation, the constant magnification mode control for the booster circuit is performed in the middle of the continuous paper feeding, the temperature of the pressurizing member, the number of paper passing, based on either an elapsed time from the time of the start-up operation starts, the image forming apparatus according to claim 1, characterized in that switching from the full power constant magnification mode to the power saving constant magnification mode. In the constant magnification mode, the boosting factor of the boosting circuit is set to a predetermined scaling factor from the start of power supply from the auxiliary power supply device to a predetermined time, and thereafter is decreased stepwise or continuously. The image forming apparatus according to claim 1 or 2 . Environmental temperature detection means for detecting the environmental temperature in the image forming apparatus,
When the temperature detected by the environmental temperature detection means is equal to or higher than a predetermined temperature, electric power is supplied to the heating means from the main power supply device and the auxiliary power supply device via the booster circuit during the start-up operation. the image forming apparatus according to any one of claims 1 to 3,. Power storage device voltage detection means for detecting the voltage value of the power storage device,
When the voltage value detected by the power storage device voltage detection means is greater than or equal to a predetermined value, power is supplied to the heating means from the main power supply device and the auxiliary power supply device via the booster circuit during the start-up operation. the image forming apparatus according to any one of claims 1 to 4, characterized in. A main power supply voltage detecting means for detecting a voltage value of the main power supply,
When the voltage value detected by the main power supply voltage detection means is greater than or equal to a predetermined value, power is supplied to the heating means from the main power supply and the auxiliary power supply via the boost circuit during the start-up operation. the image forming apparatus according to any one of claims 1 to 5, characterized in that. Said power storage device, an image forming apparatus according to any one of claims 1 to 6, characterized in that a capacitor.