JP2006330346A - Heat fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat fixing device which is made smaller and whose fixability is improved. <P>SOLUTION: The heat fixing device 1 adds power supplied from a power source (AC) 11 and power supplied from an electric storage device 13 together by an adding circuit 14, transmits the added power to a heater drive circuit 15 controllable by a heater drive control circuit 16, and supplies power according to control of the heater drive control circuit 16 to a heater 18 provided inside a roller 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat fixing apparatus that fixes a toner image formed on a recording medium to the recording medium.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines, printers, facsimiles, and the like heat a toner image formed on a recording medium by a fixing unit such as a roller that internally includes a heater that generates heat by power supplied from a power source. A heat fixing device for fixing is provided.

  FIG. 1 shows a schematic circuit relating to heating of a conventional fixing device. 1A is a schematic diagram illustrating a configuration in which a heater is heated by a power source (AC), and FIG. 1B is a schematic diagram illustrating a configuration in which a plurality of heaters are heated by the power source (AC) and a power storage device. FIG. 1C is a schematic diagram showing a configuration in which the heater is heated by switching between the power source (AC) and the power storage device.

  As shown in FIG. 1A, the heat fixing device 110 includes a power source (AC) 11 as a commercial power source as a driving power source, and supplies power to a heater 118 provided inside a roller 117 as a fixing unit. The heater drive control circuit 116 is controlled by the drive element 114 (triac). In this case, the upper limit of the power supplied to the heater 118 is the power from the power source (AC) 11. For this reason, in order to heat the roller 117 to the operating temperature in a shorter time, it is necessary to increase the power supplied from the power source (AC) 11, but generally, in order to use a rated commercial power source. There is a limit. In addition, since the difference in power consumption between heating and non-heating increases, there has been a problem when linking with other devices.

In order to compensate for the disadvantages of the heat fixing device 110 described above, there is a configuration including a power storage device in addition to a commercial power source.
For example, as illustrated in FIG. 1B, the heat fixing device 120 includes a power storage device 123 and a heater 128 b that is heated by the electric power supplied thereby, and a driving element 124 b that controls the power supply. And a heater drive control circuit 126b, that is, a configuration in which a heater 128b and a heater 128a heated by electric power supplied from a power source (AC) 121 are provided inside a roller 127 (Patent Literature). 1). In this case, since the heating by the power storage device 123 is added in addition to the heating by the power source (AC) 121, the roller 127 can be heated to the operating temperature in a shorter time.

Further, as shown in FIG. 1C, the heat fixing device 130 controls the heater drive control of the power supplied from the power source (AC) 131 and the power storage device 133 to one heater 138 in the heat fixing device 120 described above. The driving element 134a, the driving element 134b, the switching unit 134c, and the switching unit 134d that are driven by control from the circuit 136 can be switched (see Patent Document 2). In this case, the power supply (AC) 131 and the power storage device 133 can efficiently supply power, and the configuration in which one heater 138 is provided in the roller 137 can reduce the size of the roller 137.
JP 2004-240386 A JP-A-5-241387

  However, in the heat fixing device 120, since the roller 127 is provided with two heaters, it is necessary to enlarge the roller 127 (in the case of a roller type, a large diameter) and to provide a circuit for controlling each of them. It was difficult to reduce the size of the device. In the heat fixing device 130, the power supplied to the roller 137 and the upper limit thereof are either the power source (AC) 131 or the power storage device 133, and are insufficient to heat the roller 137 to the operating temperature in a shorter time. Therefore, further development was desired.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a heat-fixing apparatus that is smaller and has improved fixability.

  In order to solve the above-mentioned problems, the invention described in claim 1 includes a fixing unit that fixes a toner image on a recording medium with a heating element, a storage unit that stores DC power, and a rectifying unit that rectifies input AC power. And power addition means for superimposing the rectified power and the DC power discharged from the power storage means to supply to the heating element.

  The invention according to claim 2 is the invention according to claim 1, wherein the heating element is a single heating element that generates heat by the electric power supplied from the power adding means.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the heating element is any one of a halogen heater, a carbon heater, a heating wire, a ceramic heater, or an induction heater. .

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the power storage means is an electric double layer capacitor.

  According to the first aspect of the present invention, heat can be generated by superimposing the input AC power and the power from the power storage means, and the generated power can be controlled by controlling the added power. The fixing property can be improved.

  According to the second aspect of the present invention, the apparatus can be further downsized by using a single heating element in the fixing means.

  According to the third aspect of the present invention, the structure using a halogen heater, carbon heater, heating wire, ceramic heater or induction heater can be made smaller and fixability can be improved.

  According to the fourth aspect of the present invention, the electric double-layer capacitor can be used for small-sized, farad (F) power storage with a large capacity, and the size can be further reduced and the fixing property can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 2 is a diagram showing an outline of the heat-fixing device 1 according to the present invention, FIG. 3 is a diagram showing power waveforms in each part of the heat-fixing device 1, and (a) is a power supply (AC) power W1. (B) is the electric power W2 after rectification, (c) is the power storage device power W3, and (d) is a diagram showing the waveform of the heater driving power W4, and FIG. 4 (a) uses an induction heating method for the heater. FIG. 4 is a diagram showing an outline of a circuit configuration in which the heat fixing device 1 is provided in the image forming apparatus 100, FIG. 4B is a diagram showing an outline of a circuit configuration of a heater (IH) drive circuit 15a, and FIG. FIG. 6 is a diagram illustrating an outline of the image forming apparatus 100, and FIG. 6 is a diagram illustrating the relationship between the operation in the image forming apparatus 100 and the driving power in the heater of the heat fixing apparatus 1.

  As shown in FIG. 2, the heat fixing device 1 is a heat fixing device provided with a single heater 18 that is heated by driving power supplied to the inside of a roller 17 that fixes a recording medium carrying a toner image. The heater 18 is a halogen heater, a carbon heater, a heating wire, a ceramic heater, or an induction heating (IH: Induction Heating) coil, and any heater that can adjust the heating of the roller 17 with the supplied power. Also good.

  A circuit configuration relating to heat generation of the heat fixing device 1 includes a power source (AC) 11 and a power storage device 13 that supply driving power, power output from the power source (AC) 11 and rectified via the rectifier circuit 12, and the power storage device 13. An adding circuit 14 for adding the electric power of the heater, a heater driving control circuit 16 for controlling the heating, and a heater driving circuit for supplying the electric power input from the adding circuit 14 to the heater 18 based on a control signal from the heater driving control circuit 16 Consist of 15.

  The power source (AC) 11 is a commercial AC power source, and inputs a power source (AC) power W1 (maximum voltage value: V1) having a waveform as shown in FIG. The rectifier circuit 12 is a diode bridge, for example, and is a circuit that rectifies and outputs an AC waveform in the input AC power. The rectifier circuit 12 converts the input power (AC) power W1 into full-wave rectified power W2 (maximum voltage value: V1) as shown in FIG. The rectification in the rectifier circuit 12 is to leave a pulsating flow only by full-wave rectification as preferable when the heater is an induction heating method, but may be a rectifying device that suppresses the pulsating flow by a smoothing capacitor.

  The power storage device 13 is composed of a secondary battery (not shown in particular) that can be charged with electric power supplied from the power source (AC) 11 or can be supplied with DC power by discharging, and is shown in FIG. The power storage device power W3 (voltage value: V2) as shown is supplied to the adder circuit 14. In addition, the secondary battery is an electric double layer capacitor which is an electric storage device using an electric double layer phenomenon in which electric charges are accumulated on the boundary surface between a solid electrode such as activated carbon and an electrolytic solution (the allowable voltage of one cell is about 1.5V). ) In series.

  The adder circuit 14 adds (combines) the input rectified power W2 and the power storage device power W3, and outputs a heater driving power W4 (maximum voltage value: V1 + V2) as shown in FIG. It is a power combiner.

  The heater drive circuit 15 is a circuit that can adjust power output based on a control signal input by a switching element (not shown) and supplies power suitable for driving the heater 18. The heater drive circuit 15 adjusts the heater drive power W4 input from the adder circuit 14 based on the control signal input from the heater drive control circuit 16, and supplies the adjusted drive power to the heater 18. The heater drive control circuit 16 is a PWM (Pulse Width Modulation) signal that controls the drive of the heater 18 in accordance with a signal from a control unit that performs overall control of the operation of the heat fixing apparatus 1 or a temperature sensor that detects the temperature of the roller 17. Is a circuit for outputting a control signal to the heater drive circuit 15.

  Next, as shown in FIGS. 4 and 5, the image forming apparatus 100 is provided with a heat fixing device 1 using an induction heating method as a heater, and an image is formed on a recording medium P by overall control by a control unit (not shown). The structure to perform is demonstrated concretely.

  As shown in FIG. 4A, the power supply (AC) power W1 supplied from the power supply (AC) 11 of the heat fixing apparatus 1 is the rectifier circuit input power W11 input to the rectifier circuit 12, and the image forming apparatus 100. The power is distributed to the DC power input power W12 that is input to the DC power supply 21 that supplies power to the other components.

  The power storage device 13 includes an electric double layer capacitor 1301, a voltage detection circuit 1302, and a relay switch 1303. The power storage device 13 outputs the voltage value of the electric double layer capacitor 1301 to the heater drive control circuit 16 by the voltage detection circuit 1302, and supplies power to the adder circuit 14 by the relay switch 1303 by the control from the heater drive control circuit 16. Turn ON / OFF.

  The heater (IH) drive circuit 15a is a circuit capable of driving the induction heating type IH coil 18a, and has terminals T1 and T2 for inputting heater drive power W4 from the adder circuit 14 as input / output terminals, and a heater. Terminals T3 for inputting control signals from the drive control circuit 16 and terminals T4 and T5 for supplying driving power to the IH coil 18a are provided.

  Note that the circuit configuration of the heater (IH) drive circuit 15a was measured as shown in FIG. 4B by a voltage detection circuit 151 and a current detection circuit 152 that measure input power, a coil 153, and a capacitor 154. An oscillation control circuit 155 capable of ON / OFF control of power supply to the IH coil 18a by the IGBT element 156 based on electric power and an input control signal, and a resonance capacitor 157 matched to the IH coil 18a are provided.

  The heater drive control circuit 16 is a detection signal of a temperature sensor 161 provided in the vicinity of the roller 17, a voltage value of an electric double layer capacitor 1301 by a voltage detection circuit 1302, or a control signal from a control unit of the image forming apparatus 100 (not shown). Based on the control of the power supplied from the power storage device 13 by the relay switch 1303, the control of the heater drive power W4 by ON / OFF of the addition circuit 14, or by outputting a control signal to the heater (IH) drive circuit 15a Drive control of the IH coil 18a is performed.

  As shown in FIG. 5, the image forming apparatus 100 includes a photosensitive drum 30. The surface of the photosensitive drum 30 is charged to a predetermined potential by a charger 31, and an image is exposed by a latent image exposure unit 32. An electrostatic latent image is formed on the surface 30, the latent image is developed using a developer composed of toner and carrier by a developing device 33, visualized as a toner image, and the obtained toner image is conveyed to the photosensitive drum 30. The image is transferred by the transfer unit 34 to the recording medium P such as paper. The photosensitive drum 30 on which the transfer of the toner image has been completed is subjected to the next image formation after the remaining toner remaining on the surface is removed by the cleaner 35.

  On the other hand, the recording medium P carrying the toner image is sent from the photosensitive drum 30 to the heat fixing device 1, and the heated roller 17 in the heat fixing device 1 and the roller 19 pressed against the roller 17 are used on the recording medium P. The unfixed toner image is fixed, and an image is formed on the recording medium P.

  Here, the power supplied to the heater (IH) drive circuit 15a in accordance with the operation instruction from the image forming apparatus 100 and the detection result of the temperature sensor 161 under the control of the heater drive control circuit 16 will be described with reference to FIG. .

  Immediately after the start of image formation in the image forming apparatus 100 (during copying (immediately after warming up)), the heater drive control circuit 16 is based on the drive instruction from the control unit of the image forming apparatus 100 and the temperature state of the roller 17 immediately after startup. The power from the power storage device 13 fully charged with about 15 A of commercial power from the power supply (AC) 11 is superimposed and output to the heater (IH) drive circuit 15a (superimposition operation mode). The heater drive control circuit 16 superimposes and outputs the electric power from the power storage device 13 (the voltage drops and the current increases due to the discharge) until the temperature state of the roller 17 is stabilized during copying. When the temperature state 17 is stable, only the power from the power supply (AC) 11 is output to the heater (IH) drive circuit 15a.

  As described above, the heat fixing device 1 adds the electric power supplied from the power source (AC) 11 and the electric power supplied from the power storage device 13 by the adding circuit 14 and can be controlled by the heater driving control circuit 16. The electric power according to the control of the heater drive control circuit 16 is supplied to the circuit 15 and supplied to the IH coil 18 a provided inside the roller 17.

For this reason, since it is the structure which adds and controls the electric power from an electrical storage apparatus to a commercial power supply, it is not necessary to provide the structure which controls separately the electric power by a commercial power supply, and the electric power by an electrical storage apparatus, and can reduce a apparatus. Further, even when the temperature of the fixing roller is low at the start of copying or the like, a large amount of electric power can be supplied for driving the heater, and a stable fixing property can be realized.
Moreover, since it is the structure which makes the IH coil 18a in the inside of the roller 17 single, the roller 17 can be reduced more in size.

  Note that the description in the present embodiment shows an example of the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of the heat fixing apparatus 1 in the embodiment of the present invention can be appropriately changed without departing from the spirit of the present invention.

It is a figure which shows the outline of the circuit regarding the heating of the conventional fixing apparatus, (a) is a figure which shows the heating fixing apparatus 110 which heats a heater with a power supply (AC), (b) is a power supply (AC). 2 is a diagram showing a heating and fixing device 120 that heats a plurality of heaters by the power storage device, and FIG. 4C is a diagram showing a heating and fixing device 130 that heats the heater by switching between a power source (AC) and the power storage device. 1 is a schematic view showing an outline of a heat fixing apparatus 1 according to the present invention. FIG. 4 is a diagram illustrating a power waveform in each part of the heat fixing apparatus 1, wherein (a) is a diagram illustrating a waveform of a power supply (AC) power W1, and (b) is a diagram illustrating a waveform of a rectified power W2. (C) is a figure which shows the waveform of the electrical storage apparatus electric power W3, (d) is a figure which shows the waveform of the heater drive electric power W4. (A) is a figure which shows the outline of the circuit structure which used the heat fixing apparatus 1 which used the induction heating system for the heater for the image forming apparatus 100, (b) is the circuit structure of the heater (IH) drive circuit 15a. FIG. 1 is a diagram showing an outline of an image forming apparatus 100. FIG. 3 is a diagram illustrating the relationship between the operation in the image forming apparatus 100 and the driving power in the heater of the heat fixing apparatus 1. FIG.

Explanation of symbols

1 Heat Fixing Device 11 Power Supply (AC)
12 rectifier circuit 13 power storage device 1301 electric double layer capacitor 1302 voltage detection circuit 1303 relay switch 14 addition circuit 15 heater drive circuit 15a heater (IH) drive circuit 16 heater drive control circuit 161 temperature sensor 17, 19 roller 18 heater 18a IH coil 21 DC power source 30 photosensitive drum 31 charger 32 latent image exposure unit 33 developing unit 34 transfer unit 35 cleaner 100 image forming apparatus 151 voltage detection circuit 152 current detection circuit 153 coil 154 capacitor 155 oscillation control circuit 156 IGBT element 157 resonance capacitor P recording medium T1 to T5 Terminal W1 Power supply (AC) power W11 Rectifier circuit input power W12 DC power supply input power W2 Rectified power W3 Power storage device power W4 Heater drive power

Claims (4)

Fixing means for fixing the toner image on the recording medium by a heating element;
Power storage means for storing DC power;
Rectifying means for rectifying input AC power;
Power addition means for superimposing the rectified power and the DC power discharged from the power storage means to supply the heating element;
A heat fixing apparatus comprising:   2. The heat fixing apparatus according to claim 1, wherein the heat generating body is a single heat generating body that generates heat by the electric power supplied from the power adding means.   3. The heat fixing apparatus according to claim 1, wherein the heating element is any one of a halogen heater, a carbon heater, a heating wire, a ceramic heater, and an induction heater.   The heat fixing device according to claim 1, wherein the power storage unit is an electric double layer capacitor.

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