JP2006018192A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of speedily raising the temperature of a fixing roller while enabling another loading section to be driven even in a starting mode. <P>SOLUTION: Power which is power necessary for driving of the other loading section subtracted from specified power is supplied to a fixing heater in the starting mode. Thus the temperature of the fixing roller can be speedily raised while driving the other loading section by carrying out fine control of the power supplied to the fixing heater according to the power for the other driving section to be driven in the starting mode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus capable of variably controlling the power supplied to a fixing heater, and in particular, finely controls the power supplied to the fixing heater in accordance with the power value of another load unit that is driven during the start-up mode. Accordingly, the present invention relates to an image forming apparatus capable of quickly raising the temperature of a fixing roller while enabling driving of another load portion even in a start-up mode.

  In recent years, with increasing demand for higher speed image forming apparatuses, the wattage of a fixing heater and the wattage of a motor mounted on the image forming apparatus tend to increase, and the power consumption of the image forming apparatus tends to increase. . Further, when an element for colorization and high accuracy is added to the image forming apparatus, the number of heaters and motors and the load thereof increase, so that the power consumption further increases.

  By the way, an alternating current (hereinafter also referred to as AC) power source that is a power source of the image forming apparatus is regulated by the current rating of the outlet, and must be used below this rated current. For example, in Japan, 15A is common at 100V outlet. For this reason, currently, a method is employed in which the power consumption and the operation timing of each component are set so that the total power consumption of each component of the image forming apparatus can be accommodated with limited power.

  An image forming apparatus such as a copying machine has a plurality of operation modes, and the required power varies depending on each operation mode. The main operation modes are a rising mode until the fixing roller reaches a fixing possible temperature after turning on the main power switch of the image forming apparatus, a standby mode after the rising, and a copy mode for forming an image. In the standby mode, the fixing heater rises to the set temperature and the motor and the like are stopped, so that less power is required. On the other hand, in the copy mode, it is necessary to form a toner image on the photosensitive member, transfer the toner image onto a transfer sheet, and heat-fix the load. The load is driven by a DC power source such as a motor (hereinafter also referred to as a DC load). In addition, since a load (hereinafter also referred to as an AC load) driven by an AC power source such as a fixing heater operates, the power required for the entire apparatus increases.

  Here, in the start-up mode, the temperature of the fixing roller of the fixing unit must be increased from room temperature to a set temperature of 150 ° C. to 200 ° C. by the fixing heater, so that power consumption increases. Conventionally, the power value that can be distributed to the fixing heater in the start-up mode is determined in advance in the design stage within the range where the power consumption of the entire device does not exceed the limit value of the commercial power supply, and a constant power of this determined value is supplied. Was. In the market, it is desired to shorten the warm-up time in the start-up mode as much as possible. Conventionally, even when other loads are operated during the start-up mode, the value of power supplied to the fixing heater is the maximum output value. It was normal to be set to.

JP-A-11-219066 JP 2003-202769 A JP-A-9-160448

  However, in the prior art, a constant power of a predetermined value was supplied to the fixing heater in the rising mode, so when trying to drive another load unit during the rising mode, depending on the wattage of the load unit, In some cases, the power consumption of the entire device exceeds the limit value of the commercial power supply.

  The present invention has been made in view of the above, and by efficiently variably controlling the power supplied to the fixing heater according to the value of the power of another load unit that is driven in the start-up mode, the power can be efficiently generated. The purpose is to shorten the rise time and satisfy the market demand.

  In particular, in a color image forming apparatus, since the fixing rise time is relatively long and process control and alignment control are executed in the start-up mode, the rise time can be shortened by finely controlling their order and fixing heater power. The goal is to satisfy market requirements.

  In order to solve the above-described problems and achieve the object, the invention according to claim 1 is a fixing roller having heating means for raising the temperature by receiving power supply, and a toner image by heat from the fixing roller. A fixing unit that melts and fixes the recording material; a load unit other than the heating unit that is driven by power supply; and a power source unit that includes a power supply control unit that controls power supplied to the heating unit. The power supply control unit is configured to drive the other load unit in a start-up mode until the fixing roller reaches a fixable temperature after the power switch of the image forming apparatus is turned on. Control is performed such that power obtained by subtracting power necessary for driving the other load unit from power is supplied to the heating means.

  According to a second aspect of the present invention, in the first aspect of the present invention, the supply power control unit is configured so that the heating power is within a range in which the power consumption of the entire image forming apparatus does not exceed a predetermined limit value in the start-up mode. The power supplied to the means is controlled.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the image forming apparatus further includes an image forming unit that forms a color image in which a plurality of different color toner images are superimposed. Supply power control means is a process control that stabilizes an image forming operation for forming a toner image from a predetermined power in the start-up mode, and an alignment control that corrects a positional deviation of the toner images of different colors. It is characterized by controlling so that the electric power which deducted the electric power required in order to perform this may be supplied to the said heating means.

  The invention according to claim 4 is the invention according to claim 3, wherein the image forming unit executes the alignment control after the process control is completed in the start-up mode.

  In the image forming apparatus according to the first aspect of the present invention, when the supply power control unit drives the other load unit in the start-up mode, the power required to drive the other load unit from a predetermined power Since the electric power obtained by subtracting is controlled so as to be supplied to the heating unit, it is possible to quickly raise the temperature of the fixing roller while enabling the driving of other load portions even in the start-up mode.

  In the image forming apparatus according to the second aspect of the present invention, the supply power control unit controls the power supplied to the heating unit within a range where the power consumption of the entire image forming apparatus does not exceed a predetermined limit value. Therefore, there is an effect that the image forming apparatus can be driven within a range not exceeding the maximum power consumption (100V15A) of the standard value of the commercial power supply.

  Further, in the image forming apparatus according to the present invention (Claim 3), the supply power control means supplies the heating means with power obtained by subtracting power required for executing process control and alignment control from predetermined power. Therefore, in the start-up mode, the process control and the alignment control can be performed, and the temperature of the fixing roller can be raised quickly.

  Further, in the image forming apparatus according to the present invention (Claim 4), since the image forming unit executes the alignment control after the process control is completed in the start-up mode, the image after the process control is performed is stable. Thus, it is possible to perform alignment, and the control accuracy can be further improved.

  Exemplary embodiments of an image forming apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings.

  FIG. 1 is an external view of a color image forming apparatus according to the present invention. As shown in the figure, the image forming apparatus 1 converts an automatic document feeder 2, an operation unit 3 for inputting job information such as the number of copies, and a document sent by the automatic document feeder 2 into read image information. A reading unit 4, an image forming engine unit 5 (image forming unit) that forms an image of the read original and transfers it to a recording paper, a paper feeding unit 6 that stores the recording paper and sends the recording paper to the image forming engine unit 5, It has a duplex unit 7 that is used when images are formed on both sides of a recording sheet, and a finisher 8 that staples the recording sheet on which the image is formed.

  The engine unit 9 of the image forming engine unit 5 includes, for each color of CMYK (blue red yellow black), as shown in the configuration diagram of FIG. Provided downstream of the device 11 and the charging device 11 in the rotational direction of the photosensitive member 10, provided on the downstream side of the mirror 13 that makes the laser beam 12 incident on the surface of the photosensitive member 10, and the incident portion of the laser beam 12. The developing device 14 includes a developing device 14, a transfer device 15 provided on the downstream side of the developing device 14, and a cleaning device 16 provided on the downstream side of the transfer device 15. Each color toner image formed on the photosensitive member 10 is transferred to an intermediate transfer member in the order of Yellow → Magenta → Cyan → blacK, and a color image is transferred from the intermediate transfer member to a recording sheet. The color image transferred to the recording paper is melted and fixed on the recording paper by the downstream fixing device 17 (fixing unit).

  When the image forming apparatus 1 forms an image, the surface of the rotating photoreceptor 10 is uniformly charged by the charging device 11, and the laser beam 12 emitted according to the image information is reflected by the mirror 13 and charged. It enters the surface of the photoreceptor 10 and forms an electrostatic latent image corresponding to the image to be formed. The electrostatic latent image formed on the surface of the photoreceptor 10 is developed by the developing device 14 to form a toner image. On the other hand, the recording paper fed from the paper feeding unit 6 is temporarily stopped at the position of the registration roller 18. When the toner image formed on the photoconductor 10 reaches the transfer device 15, the recording paper is sent out from the registration roller 18 at the timing of the image position, and the toner image formed on the photoconductor 10 is transferred to the recording paper by the transfer device 15. Transcript to. The recording paper onto which the toner image has been transferred by the transfer device 15 is sent to the fixing device 17 where the toner of the toner image transferred onto the recording paper is heated and melted and fixed. Further, the toner remaining on the photosensitive member 10 without being transferred to the recording paper is removed by the cleaning device 16.

  As shown in the block diagram of FIG. 3, the fixing device 17 for fixing the toner image transferred onto the recording paper includes a fixing roller 20 having a fixing heater 19 (heating means) therein, and a pressure member pressed against the fixing roller 20. It has a pressure roller 21 and a temperature sensor 22 made of, for example, a thermistor. The roller base of the fixing roller 20 and the pressure roller 21 uses a metal such as aluminum or iron to prevent durability and deformation due to pressure. In particular, the fixing roller 20 is formed with a large heat capacity so that the heating temperature can be stably maintained when heated. The fixing heater 19 provided in the fixing roller 20 extends the life by using a halogen heater that heats surrounding objects, for example, when a heating wire in a glass tube emits light when supplied with electric power. . In addition, you may use not only a halogen heater but another resistance heating element. Further, a release layer is formed on the surface of the roller base of the fixing roller 20 and the pressure roller 21 to prevent the toner from adhering to the inner surface of the roller base, and a blackening process is performed on the inner surface of the roller base to efficiently absorb the heat of the halogen heater. I am doing. The toner image transferred to the recording paper 23 is heated and pressed at the nip portion between the heated fixing roller 20 and the pressure roller 21 of the fixing device 17 and fixed by the action.

  The power supply device 25 that supplies power to the image forming apparatus 1 includes a main power switch SW1, a PSU unit 26, and an AC control unit 27, as shown in the configuration diagram of FIG. The AC control unit 27 supplies an alternating current to an AC load unit driven by an alternating current, and the PSU unit 26 supplies a direct current to a DC load unit driven by a direct current.

  The AC load unit is, for example, a heater. In the present embodiment, the AC load section includes a fixing heater section 19 having two 600 W fixing heaters HT1 and HT2, and a dehumidifying heater section 28. The role of the dehumidifying heater unit 28 is to dehumidify the transfer paper when the power is turned off and to prevent condensation of the optical system.

  The DC load unit is, for example, a printed circuit board or a motor. In the present embodiment, the DC load unit includes a control unit 30 that controls the operation of the image forming apparatus 1, a power load unit 31 such as a motor in the image forming engine unit 5 and the fixing device 17, and the like.

  An alternating current is supplied to the power supply unit 25 from the AC power supply 40 via the power cord, and is supplied to the PSU unit 26 and the AC control unit 27, respectively.

  The PSU unit 26 generates a DC power source (3.3V, 5V, 12V, 24V, etc.) necessary for the image forming apparatus by an internal converter (not shown) and supplies the DC load unit. The PSU unit 26 supplies a 24 V DC current as an auxiliary power source to the AC control unit 27.

  FIG. 5 shows a block diagram of the AC control unit 27. The AC control unit 27 includes an inverter 271 that converts a 24V DC current supplied from the PSU unit 26 into an AC current, a power relay RL that switches an AC current supply destination generated by the inverter 271, and an AC voltage that detects an AC input voltage. A detection circuit 272, a zero-cross detection circuit 273 that detects a zero-cross point of the AC input voltage, and triacs TR1 and TR2 that control power supply to the two fixing heaters HT1 and HT2 by a lighting signal from the control unit 30 are provided.

  In accordance with the power relay ON / OFF signal from the control unit 30, the power relay RL switches between supplying the alternating current generated by the inverter 271 to the fixing heater side or the dehumidifying heater side. Normally, the 24V power supplied from the AC control unit 27 is supplied to the fixing heater unit 19 side when the main power switch SW1 is ON, and is supplied to the dehumidifying heater unit 28 side when the main power switch SW1 is OFF. The When supplied to the fixing heater unit 19, the alternating current generated by the inverter 271 is supplied to the AC voltage detection circuit 272.

  The AC voltage detection circuit 272 detects the AC input from the AC power source and / or the input voltage of the alternating current generated by the inverter 271, and transmits the obtained detection signal to the control unit 30. Further, the zero cross detection circuit 273 detects a zero cross point of the AC input voltage and transmits the obtained detection signal to the control unit 30.

  The control unit 30 controls the overall operation of the image forming apparatus 1. The image forming apparatus 1 according to the present invention is driven in a range that does not exceed the maximum power consumption 1500 W (100 V 15 A) of the standard value of the commercial power source. The control unit 30 calculates the power consumption amount for driving each load unit of the image forming apparatus 1 so that the power consumption of the entire apparatus does not exceed 1500 W, and sets the power value supplied to the fixing heaters HT1 and HT2. Then, the AC controller 27 is controlled to supply power to the fixing heaters HT1 and HT2. In addition, the control unit 30 controls the driving of the creation engine unit 5 during execution of process control for stabilizing image forming conditions and alignment control for correcting the positional deviation of toner images of different colors.

  Next, the operation in the start-up mode after the main power switch SW1 of the image forming apparatus 1 is turned on until the fixing roller reaches the fixable temperature will be described.

  First, the fixing heaters HT1 and HT2 are turned on, and the two fixing rollers incorporating the fixing heaters HT1 and HT2 are rotated by a fixing drive (motor) to uniformize the heat in the rollers (mode 1). Note that the power consumption of the substrate, PSU, etc. that is always consumed in the image forming apparatus 1 is 300 W, and in mode 1, the power required for fixing driving is 100 W.

  Next, in a state where the fixing heaters HT1 and HT2 are turned on, the potential of the photosensitive member is maintained in an optimal state, and an optimal toner amount is adjusted to stabilize the image forming conditions, which is called process control. The image forming operation of the photosensitive member and the intermediate transfer member is executed for a predetermined time (mode 2). In mode 2, the power required for process control is 300W.

  After the process control is completed, main scanning / sub-scanning alignment between the four colors constituting the color image, which is called alignment control, is performed while the fixing heaters HT1 and HT2 are turned on. The basic image pattern is transferred from the four photoconductors to the intermediate transfer member, and the deviation between the respective colors is detected, the timing of laser writing to the photoconductor is adjusted, the speed of the photoconductor drive motor is adjusted, Align. Since it is necessary to detect a slight misalignment between the colors, the control accuracy is improved when the process control is performed in a stable state. In terms of operation, an image forming operation is executed for a certain period of time as in the process control (mode 3). In mode 3, the power required for alignment control is 300W.

  When the alignment control is completed, the image forming operation is stopped, and only the fixing heater and the fixing drive are turned on as in mode 1 (mode 4).

  When the fixing temperature reaches a certain value near the set temperature, the fixing driving is stopped and only the fixing heater is turned on (mode 5). When the set temperature (about 200 ° C.) is reached, the fixing heater is turned off, and the start-up mode ends.

  FIG. 6 shows the wattage of the load portion other than the fixing heater in the above-described start-up modes 1 to 5, the total wattage of the fixing heaters HT1 and HT2, the wattage and lighting rate of the heater HT1, and the heater HT2. It summarizes the wattage and lighting rate.

  The control unit 30 calculates the wattage obtained by subtracting the wattage consumed by each load unit other than the mode 1 to mode 5 fixing heater from the 1500 W power as the wattage supplied to the fixing heater. Then, the control unit 30 instructs the AC control unit 27 to supply power to the fixing heater in a range that does not exceed the range in which the current of the entire apparatus can flow through the power cord.

  The control unit 30 calculates the consumed wattage of each load unit other than the mode 1 to mode 5 fixing heater and subtracts the consumed wattage of each load unit other than the fixing heater from the maximum power consumption 1500 W of the image forming apparatus. Is determined as the power value to be supplied to the fixing heater unit 19. Then, the power value to be distributed to the fixing heaters HT1 and HT2 is determined.

  In mode 1, the power consumption required to drive the load unit other than the fixing heater is 400 W obtained by adding 300 W required for fixing driving (motor) to 300 W that is always consumed by the substrate / PSU. Accordingly, the power value that can be supplied to the fixing heater unit 19 is 1100 W obtained by subtracting 400 W from the maximum power consumption 1500 W.

  The wattage of the fixing heaters HT1 and HT2 is 600 W, and the total wattage of the fixing heater unit 19 is 1200 W. In the present embodiment, when the power value that can be supplied to the fixing heater unit 19 is less than 1200 W, power is preferentially supplied to the fixing heater HT2. In mode 1, since the total power value that can be supplied to the fixing heater unit 19 is 1100 W, the control unit 30 controls the power supplied to the fixing heater HT1 to be reduced to 500 W (lighting rate 83%). . Specifically, the control unit 30 transmits a lighting signal to the triac TR1, and performs ON / OFF switching control of the heater trigger of the triac TR1.

  In mode 2, the value of power consumption required to drive the load unit other than the fixing heater is 600 W obtained by adding 300 W, which is always consumed by the substrate / PSU, to 300 W required for process control. Therefore, the power value that can be supplied to the fixing heater unit 19 is 900 W obtained by subtracting 600 W from the maximum power consumption 1500 W.

  In mode 2, the control unit 30 controls the power supplied to the fixing heater HT1 to be reduced to 300 W (lighting rate: 50%), whereby the total wattage supplied to the fixing heater unit 19 is set to 900 W, and image formation is performed. Control is performed so that the overall power consumption of the apparatus does not exceed 1500 W, which is the maximum power consumption.

  In mode 3, the value of power consumption required to drive the load unit other than the fixing heater is 600 W obtained by adding 300 W, which is always consumed by the substrate / PSU, to 300 W, which is necessary for alignment control. Therefore, the power value that can be supplied to the fixing heater unit 19 is 900 W obtained by subtracting 600 W from the maximum power consumption 1500 W.

  In mode 3, the control unit 30 controls the power supplied to the fixing heater HT1 to be reduced to 300 W (lighting rate: 50%), whereby the total wattage supplied to the fixing heater unit 19 is set to 900 W, and image formation is performed. Control is performed so that the overall power consumption of the apparatus does not exceed 1500 W, which is the maximum power consumption.

  In mode 4, the power consumption value required to drive the load unit other than the fixing heater is 400 W, which is 100 W required for fixing driving (motor) and 300 W that is always consumed by the substrate / PSU. is there. Accordingly, the power value that can be supplied to the fixing heater unit 19 is 1100 W obtained by subtracting 400 W from the maximum power consumption 1500 W.

  In mode 4, the control unit 30 controls the power supplied to the fixing heater HT1 to be reduced to 500 W (lighting rate 83%), thereby setting the total wattage supplied to the fixing heater unit 19 to 1100 W and image formation. Control is performed so that the overall power consumption of the apparatus does not exceed 1500 W, which is the maximum power consumption.

  In mode 5, the power consumption value necessary for driving the load unit other than the fixing heater is only 300 W, which is always consumed by the substrate / PSU, and the power value that can be supplied to the fixing heater unit 19 is The maximum power consumption is 1200 W obtained by subtracting 300 W from 1500 W. In mode 5, since the power value that can be supplied to the fixing heater unit 19 does not fall below the total wattage 1200W of the fixing heater unit 19, the control unit 30 causes the fixing heaters HT1 and HT2 to have a lighting rate of 100% (600W). ) To drive.

  Next, the lighting control of the fixing heater in the AC control unit 27 will be described. FIG. 7 is an example of lighting control of the fixing heater HT1 when the lighting rate is 50%. The control unit 30 synchronizes with the zero-cross detection signal from the zero-cross detection circuit 273 to turn on / off the triac TR1 in the AC control unit 27 so that the heater trigger is switched on and off at a rate of 5/10 half wave. Send. Due to this lighting signal, the current input to the fixing heater HT1 is turned off by 5 half waves in 10 half waves, so the effective power value to the fixing heater HT1 is suppressed to a current value of 50% during full lighting. .

  In this embodiment, when the 600 W fixing heaters HT1 and HT2 are set to the wattage of each mode, the total wattage is adjusted by controlling the lighting of only the fixing heater HT1. The total wattage may be adjusted by controlling the lighting of only HT2, or the total wattage may be adjusted by controlling the lighting of both the fixing heaters HT1 and HT2.

  As described above, according to the present embodiment, the AC control unit 27 finely controls the power supplied to the fixing heater in accordance with the power of the other load unit that is driven in the start-up mode. Even during the mode, it is possible to quickly raise the temperature of the fixing roller while making it possible to drive other load portions.

  As described above, the image forming apparatus of the present invention can quickly drive the temperature of the fixing roller while enabling the driving of other load portions even in the start-up mode, so that the copying machine, printer, facsimile, etc. It can be suitably used as an image forming apparatus, particularly as a color image forming apparatus.

1 is an external view of a color image forming apparatus. It is a block diagram of an image forming engine unit in the color image forming apparatus. FIG. 2 is a cross-sectional view of a fixing device in a color image forming apparatus. 2 is a block diagram of a power supply device in the color image forming apparatus. FIG. 2 is a block diagram of an AC control unit in the color image forming apparatus. FIG. It is a graph which shows the wattage and the lighting rate of each component in mode 1 to mode 5 of start-up mode. It is a figure which shows an example of lighting control of the fixing heater HT1 when the lighting rate is 50%.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 17 Fixing device 19 Fixing heater part 20 Fixing roller 21 Pressure roller 25 Power supply device 26 PSU part 27 AC control part 28 Dehumidification heater part 30 Control part 31 Power load part

Claims (4)

A fixing roller having a heating means for raising the temperature by receiving power supply,
A fixing unit that melts and fixes a toner image on a recording material by heat from the fixing roller;
A load unit other than the heating means that is driven by receiving power supply; and
A power supply unit comprising supply power control means for controlling the power supplied to the heating means;
With
The supply power control means starts from a predetermined power when driving the other load unit in a start-up mode after the power switch of the image forming apparatus is turned on and until the fixing roller reaches a fixable temperature. An image forming apparatus that controls to supply the heating means with power obtained by subtracting power required to drive the other load unit.   2. The power supply control unit controls power supplied to the heating unit in the start-up mode in a range where power consumption of the entire image forming apparatus does not exceed a predetermined limit value. Image forming apparatus. The image forming apparatus further includes an image forming unit that forms a color image obtained by superimposing a plurality of different color toner images,
The supply power control means is a process control that stabilizes an image forming operation for forming a toner image from a predetermined power in the start-up mode, and an alignment that corrects a positional deviation between the toner images of different colors. 3. The image forming apparatus according to claim 1, wherein control is performed so that power obtained by subtracting power necessary for executing control is supplied to the heating unit.   The image forming apparatus according to claim 3, wherein the image forming unit executes the alignment control after the process control is completed in the start-up mode.

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