JP2004233745A - Fixing heater controller and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that electric power of a fixing section is consumed beyond a necessary amount. <P>SOLUTION: The fixing heater controller for an image forming apparatus which forms a toner image on a recording material and fixes the toner image on the recording material to the recording material in the fixing section 13 having the fixing heater to be fed with electricity from a commercial power source is equipped with a voltage detecting means for detecting the voltage of the commercial power source and a control means 18 for controlling the electrified time and non-electrified time of the fixing heater per unit time from the result of the detection by the voltage detecting means. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixing heater control device and an image forming apparatus such as a copying machine, a printer, and a facsimile.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image forming apparatus, power is supplied from a commercial power supply to a fixing heater of a fixing unit to monitor the temperature of the fixing unit. Thus, the temperature of the fixing unit is controlled by controlling the temperature in accordance with the above. In order to prevent image formation failure even when the voltage of the commercial power supply reaches the lower limit, or to finish the startup time until image formation becomes possible within a specified time, consider the variation in the resistance value of the fixing heater. A fixing heater that generates a large amount of heat was mounted. The method of controlling the temperature of the fixing unit is a method of determining the duty of the energizing time and the non-energizing time of the fixing heater per unit time based on a difference between the fixing unit temperature and the target temperature.
[0003]
Patent Document 1 discloses that a developing unit attaches toner to an electrostatic latent image formed on a photoconductor, develops the toner, transfers the toner to recording paper to form a visible image, and uses a fixing heater to form a toner image. In an image forming apparatus for fixing an AC voltage to recording paper, a zero-cross detecting means for detecting an AC voltage fluctuation applied to a fixing heater, a fixing temperature detecting means for detecting a fixing unit temperature, and a voltage fluctuation of an AC power supply Means for detecting a peak of an AC voltage for detecting an error, a mode managing means for managing a standby mode selected by an operation / display unit of the apparatus, and a fixing control for controlling a phase of a fixing heater based on the standby mode and a temperature of the fixing unit. Means, a memory means for storing phase control data, and a switching means for controlling the supply of an AC voltage to the fixing heater. Flip fixing heater current control device, characterized in that configured to perform energization control of the fixing heater is described.
[0004]
Patent Document 2 discloses that a voltage applied to an exposure lamp is controlled to a constant voltage, and a zero cross signal indicating a zero cross of an input voltage and a trigger signal for determining a constant effective voltage applied to the exposure lamp are output. And a heater power control unit for controlling power supplied to a heater comprising a heating resistor of the fixing device, wherein the heater power control unit includes the zero cross signal and the trigger. A detection unit that detects a voltage change and a frequency change of an input voltage from a signal, and a storage unit that stores and holds a voltage value set as a voltage applied to the exposure lamp and a resistance value of the heater, The supply voltage to the heater is determined from the voltage value and the resistance value stored in the storage unit while monitoring the detection result of the detection unit. The image forming apparatus is described which is characterized by controlling the application voltage of the heater such that the value.
[0005]
Patent Document 3 discloses an electrophotographic apparatus having a fixing device that forms a toner image on a recording medium, transfers the toner image onto a transfer material to form a transfer image, and fixes at least the transfer image on the transfer material. Image recording means using a system, an applied voltage detecting means for detecting an applied voltage to the fixing device, a temperature detecting means for detecting a temperature state of a heating portion of the fixing device, and controlling a temperature state of the heating portion. In an electrophotographic apparatus having a heating unit control unit that performs heating and a heating unit control table that has control data for driving the heating unit control unit, when performing temperature control of the heating unit that the fixing unit has, The two parameters of the applied voltage to the heating section and the temperature state are used as parameters for selecting the control data from the section control table, and the applied voltage detecting means has independent conversion means for the applied voltage. Electrophotographic apparatus characterized by further detection is described.
[0006]
[Patent Document 1]
JP-A-9-101718 [Patent Document 2]
JP-A-5-35012 [Patent Document 3]
JP-A-8-185083
[Problems to be solved by the invention]
In the above-described method of controlling the temperature of the fixing unit, the resistance value of the fixing heater is individually different, and the temperature of the fixing unit is controlled under the same condition even when the power supply voltage is different for each user. When the AC input voltage is higher than the rated value, the power consumption of the fixing unit may be consumed more than necessary.
[0008]
SUMMARY An advantage of some aspects of the invention is to provide a fixing heater control device and an image forming apparatus capable of controlling the maximum power consumption of a fixing unit.
Still another object of the present invention is to provide a fixing heater control device and an image forming apparatus capable of keeping the maximum power consumption of the fixing unit constant.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 forms a toner image on a recording material, and transfers the toner image on the recording material to the recording material in a fixing unit having a fixing heater supplied from a commercial power supply. In a fixing heater control device of an image forming apparatus to be fixed, a voltage detecting means for detecting a voltage of the commercial power supply, and an energizing time and a non-energizing time of the fixing heater per unit time are controlled based on a detection result of the voltage detecting means. Control means.
[0010]
According to a second aspect of the present invention, in the fixing heater control device according to the first aspect, the control unit determines a power supply time of the fixing heater so that power consumption of the fixing unit is constant regardless of variation in the commercial power supply. The non-energization time is controlled.
[0011]
According to a third aspect of the present invention, in the image forming apparatus having the fixing heater control device according to the second aspect, the control unit controls the energization time and the non-energization time of the fixing heater by a warm-up time when the power is turned on. That's what's up.
[0012]
According to a fourth aspect of the present invention, in the image forming apparatus having the fixing heater control device according to the second aspect, the control unit controls the energizing time and the non-energizing time of the fixing heater in a low power mode or an energy saving mode. This is at the time of warm-up after returning from the mode.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of the present invention. This embodiment is an example of a printer as an image forming apparatus.
The image forming unit 11 includes a plurality of photosensitive drums and toner supply units as image carriers, forms images of different colors on each photosensitive drum, and forms images of each color on each photosensitive drum. A color image is formed on a recording sheet by superimposing and transferring the image on a recording sheet as a recording material.
[0014]
The optical writing unit 12 as an exposure unit drives a laser diode by modulation with an image signal of each color, and irradiates the plurality of photosensitive drums with laser light modulated by the image signal of each color from the laser diode. By performing the exposure, an electrostatic latent image corresponding to the image signal of each color is formed on each photosensitive drum. That is, in the image forming unit 11, the plurality of photoconductor drums are each driven to rotate by the driving unit, uniformly charged by the charging unit, and then modulated by the image signal of each color from the optical writing unit 12. Exposure with light forms an electrostatic latent image corresponding to the image signal of each color. The electrostatic latent images corresponding to the image signals of the respective colors on the respective photosensitive drums are respectively developed with the respective color toners by developing means including a toner supply unit, and become the respective color toner images. A recording sheet is fed from a sheet feeding device, and a color image is formed on the recording sheet by transferring a toner image of each color on each photosensitive drum by a transfer unit in a superimposed manner.
[0015]
The fixing unit 13 has a fixing heater, and the recording paper on which the color image has been formed by the image forming unit 11 is conveyed to fix the image (toner) on the recording paper to the recording paper. The fixing unit 13 includes a fixing roller (or a fixing belt) as a fixing member that is driven to rotate by a driving source and a pressing roller as a pressing member, which heats and presses the recording paper passing through the nip portion. , An image (toner) is fixed, and at least one of a fixing roller (or a fixing belt) and a pressure roller is heated by a fixing heater.
[0016]
The operation unit 14 is a part operated by a user or an operator to set the status of the printer. The ROM 15 stores a program for controlling the printer and fixed parameters. The RAM 16 stores initial settings of the printer and is backed up by a battery. The communication I / F 17 is connected to the host via a LAN or the like, and controls external I / F, and controls external input / output data such as image data. The controller 18 is a part that controls the printer, includes a CPU, and controls each part of the printer via a bus.
[0017]
FIG. 2 shows a circuit for controlling energization to the fixing heater in this embodiment. The fixing heater relay control unit 21 is a unit that controls power supply from a commercial power supply to the fixing heaters 1 and 2 of the fixing unit 13, and includes a transistor 31, a diode 32, a relay 33, and the like. The AC power supplied from the commercial power supply is turned on / off by a contact 33 a of a relay 33 via a fuse 34 and a noise filter 35.
[0018]
A control board 20 as a control unit included in the controller 18 controls the relay 33 via the transistor 31 by a relay control signal for fixing heater power supply, and closes a contact 33a of the relay 33 when the printer is turned on (power on). Then, AC power from the commercial power supply is supplied. Further, when the fixing heaters 1, 2 and the like become abnormal, the control board 20 releases the contact 33a of the relay 33 to cut off the AC power from the commercial power supply.
[0019]
The zero-cross detection unit 22 includes a full-wave rectifier circuit 36, a photocoupler 37, a transistor 38, and the like, and detects a zero-cross of the AC voltage from the contact point 33a of the relay 33 in the fixing heater relay control unit 21 to generate a zero-cross signal. 20. The control board 20 uses the zero-cross signal from the zero-cross detector 22 as a reference for the timing when the fixing heaters 1 and 2 are turned on / off.
[0020]
The AC voltage detection unit 23 as a voltage detection unit is configured by a transformer 39, a full-wave rectifier circuit 40, and the like. The AC voltage from the contact 33a of the relay 33 in the fixing heater relay control unit 21 is converted into a low voltage by the transformer 39. By performing full-wave rectification by the full-wave rectifier circuit 40, an AC voltage detection signal that can be detected on the control board 20 side is generated. The fixing heater control unit 24 includes transistors 41 and 42, photocouplers 43 and 44, and triacs 45 and 46 as switch elements. The fixing heaters 1 and 2 are connected to a fuse 34, a noise filter 35, and a relay 33 from a commercial power supply. AC power is supplied via triacs 45 and 46 via 33a, respectively. The control board 20 turns on / off the triacs 45 and 46 via the transistors 41 and 42 and the photocouplers 43 and 44 in response to the fixing heater 1 control signal and the fixing heater 2 control signal, thereby reducing the energizing time of the fixing heaters 1 and 2. Controls the non-energizing time. In this case, the control board 20 turns on / off the triacs 45 and 46 at the zero cross of the AC voltage from the commercial power supply according to the zero cross signal from the zero cross detector 22.
[0021]
The fixing heaters 1 and 2 operate when the AC voltage from the commercial power source is the minimum voltage among the variations in the commercial power source (variations in the AC power from the commercial power source) and when 100% power is supplied per unit time of control. The heat value is set so that the power consumption becomes the maximum power consumption specified by the device. The temperature of the fixing unit 13 (the surface temperature of the fixing member) is detected by a temperature detecting unit such as a thermistor, and a temperature detection signal from the temperature detecting unit is input to the control board 20.
[0022]
Generally, in the temperature control method of the fixing heater, a fixed time is determined as the control interval unit time. The control board 20 detects the temperature of the fixing unit 13 at the beginning of each control unit time interval (at the beginning of each control unit time) based on the temperature detection signal from the temperature detection unit, and controls the control unit time of the fixing heaters 1 and 2. For example, as shown in FIG. 3, the ratio of the duty ratio of the energized or non-energized state to the target temperature: tr stored in the ROM 15 and the temperature of the fixing unit 13 is determined by the temperature: ts of the fixing unit 13 detected by the temperature detecting unit. : Difference from ts: a parameter corresponding to t = tr−ts is selected from ROM 15 and triacs 45 and 46 are turned on / off by the parameter to reduce the power supplied to fixing heaters 1 and 2 to the temperature of fixing unit 13. Is controlled so that the temperature of the fixing heaters 1 and 2 becomes energized or de-energized at each control unit time so that the temperature of the fixing unit 13 becomes the target temperature: tr.
[0023]
In the present embodiment, the maximum power consumption of the fixing heaters 1 and 2 per unit control time is constant regardless of the variation of the commercial power supply. In this embodiment, when the AC voltage from the commercial power source is the minimum voltage among the variations in the commercial power source (variations in the AC power from the commercial power source) and when 100% of the power is supplied per control unit time, Since the fixing heaters 1 and 2 whose heat generation amounts are set so as to have the maximum power consumption specified by the apparatus are mounted, if the duty Duty of the fixing heaters 1 and 2 per control unit time is 100%, The maximum power consumption of the fixing heaters 1 and 2 differs depending on the variation of the commercial power supply.
[0024]
Therefore, when the AC voltage from the commercial power supply is larger than the minimum voltage, the control board 20 corrects the maximum energizing time T of the fixing heaters 1 and 2 per control unit time so as to shorten the triac 45 and 46. On / off control. Specifically, the minimum voltage of the AC voltage from the commercial power supply: Vmin, and the unit control time (control unit time): Ta. The power consumption of the fixing heaters 1 and 2 is (power consumption of the fixing heaters 1 and 2: W) = (applied voltage of the fixing heaters 1 and 2: V) × (applied voltage of the fixing heaters 1 and 2: V) ÷ ( Since it is given by the equation of the resistance value of the fixing heaters 1 and 2: R), it is obtained as (maximum energizing time of the fixing heaters 1 and 2: T) = (Vmin × Vmin) ÷ (V × V) × Ta. Then, the control board 20 obtains the maximum energizing time: T of the fixing heaters 1 and 2 per control unit time from the AC voltage from the commercial power supply based on the AC voltage detection signal from the AC voltage detecting unit 23 by the above equation, The maximum energizing time of the fixing heaters 1 and 2 per control unit time is determined as the maximum energizing time per control unit time, and is stored (updated) in the memory, so that the fixing heaters 1 and 2 per control unit time are controlled. The maximum energization duty is corrected. Then, the control board 20 corrects the control unit time of the maximum energizing time and the non-energizing time of the fixing heaters 1 and 2 according to the maximum energizing time per control unit time stored in the memory, and sets the triacs 45 and 46 to the same. On / off control is performed as described above with the corrected control unit time, and the maximum power consumption of the fixing heaters 1 and 2 per control unit time is controlled to be constant.
[0025]
FIG. 4 shows an operation flow of the present embodiment. The control board 20 detects the voltage of the commercial power supply from the AC voltage detection signal from the AC voltage detection unit 23 at the time of warm-up immediately after returning from the low power mode or the energy saving mode or at the time of power-on (power-on). Based on the value, the maximum energization duty of the fixing heaters 1 and 2 per control unit time is determined as described above, and the determined maximum energization duty of the fixing heaters 1 and 2 per control unit time is stored (updated) in the memory. Thus, the maximum energization duty of the fixing heaters 1 and 2 per control unit time is corrected. Then, the control board 20 corrects the control unit time of the maximum energizing time and the non-energizing time of the fixing heaters 1 and 2 according to the maximum energizing time per control unit time stored in the memory, and sets the triacs 45 and 46 to the same. On / off control is performed as described above with the corrected control unit time, and the maximum power consumption of the fixing heaters 1 and 2 per control unit time is controlled to be constant.
[0026]
Thus, according to the present embodiment, the voltage of the commercial power supply applied to the fixing heaters 1 and 2 mounted on the printer is detected, and the maximum energizing time of the fixing heaters 1 and 2 is determined by the voltage of the commercial power supply. The maximum power consumption of the fixing heaters 1 and 2 can be controlled by correcting the control unit time of the non-energization time.
[0027]
Further, according to the present embodiment, the voltage of the commercial power supply applied to the fixing heaters 1 and 2 mounted on the printer is detected, and the maximum energizing time of the fixing heaters 1 and 2 and the non-energized state are determined by the voltage of the commercial power supply. By correcting the control unit time of time, it is possible to control the maximum power consumption of the fixing heaters 1 and 2 to be constant.
[0028]
Further, according to the present embodiment, the AC voltage applied to the fixing heaters 1 and 2 is detected at the time of warm-up when the power is turned on, and the maximum energizing time and the non-energizing time of the fixing heaters 1 and 2 per control unit time are determined. By correcting the control unit time, the maximum power consumption of the fixing heaters 1 and 2 can be made constant.
[0029]
According to the present embodiment, the AC voltage applied to the fixing heaters 1 and 2 is detected at the time of warm-up immediately after returning from the low power mode or the energy saving mode, and the maximum energizing time of the fixing heaters 1 and 2 By correcting the control unit time of the time, the maximum power consumption of the fixing heaters 1 and 2 can be made constant.
The present invention is not limited to the above embodiment, but can be applied to image forming apparatuses other than the above embodiment, such as copiers, printers, and facsimile machines.
[0030]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a fixing heater control device and an image forming apparatus capable of controlling the maximum power consumption of a fixing unit.
Further, it is possible to provide a fixing heater control device and an image forming apparatus capable of keeping the maximum power consumption of the fixing unit constant.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a circuit diagram showing a circuit for controlling energization to a fixing heater in the embodiment.
FIG. 3 is a diagram illustrating a relationship between a difference t between a target temperature and a temperature of a fixing unit and an energizing time (%) of a fixing heater in the embodiment.
FIG. 4 is a flowchart showing an operation flow of the embodiment.
[Explanation of symbols]
1, 2 Fixing heater 20 Control board 21 Fixing heater relay controller 22 Zero cross detector 23 AC voltage detector 24 Fixing heater controller

Claims (4)

In a fixing heater control device of an image forming apparatus for forming a toner image on a recording material and fixing the toner image on the recording material to the recording material by a fixing unit having a fixing heater supplied from a commercial power supply, A voltage detecting means for detecting the voltage of the fixing heater, and a control means for controlling the energizing time and the non-energizing time of the fixing heater per unit time based on the detection result of the voltage detecting means. . 2. The fixing heater control device according to claim 1, wherein the control unit controls energization time and non-energization time of the fixing heater so that power consumption of the fixing unit is constant regardless of variation in the commercial power supply. 3. A fixing heater control device. 3. An image forming apparatus comprising the fixing heater control device according to claim 2, wherein the control unit controls the energizing time and the non-energizing time of the fixing heater at a warm-up time when the power is turned on. Image forming apparatus. 3. An image forming apparatus comprising the fixing heater control device according to claim 2, wherein the control unit controls the energizing time and the non-energizing time of the fixing heater by warming up after returning from a low power mode or an energy saving mode. An image forming apparatus, characterized in that it is time.

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