JP3734973B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly, to a reduction in apparatus start-up time.
[0002]
[Prior art]
In a conventional image forming apparatus such as a copying machine or a printer, an image forming operation is executed after the main switch of the apparatus is turned on and the fixing device reaches a set temperature. The waiting time during this period may reach 5 minutes or more with a long apparatus, and the operability is not good.
[0003]
Various proposals have been made in the past in order to shorten the startup time of the fixing device. For example, there is one that shortens the rise time by controlling the energization current to the fixing heater while maintaining the input current of the image forming apparatus below a predetermined value. In some cases, the rise time is shortened by switching the upper limit of the power consumed by the fixing unit between when the image forming apparatus is activated and when it is normal.
[0004]
[Problems to be solved by the invention]
However, although the conventional start-up time shortening technique has a certain effect, there is a problem that further shortening of the start-up time cannot be dealt with due to the limitation of the input current to the image forming apparatus.
[0005]
Conventionally, in order to shorten the start-up time of the fixing device, the remaining heat for energizing the fixing heater is also performed during standby. As a result, image formation can be performed without waiting time when necessary, but there is also a problem that wasteful power is consumed due to residual heat when the image formation frequency is low.
[0006]
The present invention solves the above-described problems in the conventional image forming apparatus, and includes an image forming apparatus including a fixing unit that can quickly start up and can prevent duplication with an inrush current inside the main power supply accompanying the start of the main power supply. It is an issue to provide.
[0007]
It is another object of the present invention to provide an image forming apparatus that rises quickly while suppressing power consumption during standby as much as possible.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a first power supply apparatus to which AC power is supplied when a power switch of the apparatus main body is turned on, and a first power supply that is activated by supply of power from the first power supply apparatus. Control means, a second power supply device whose output is turned on / off by the first control means, a second control means that is activated by the supply of power from the second power supply device, and the first control means And a fixing means for supplying AC power from the power supply of the main body device via the switch means. When the release means is turned on, the switch means is turned on. When starting the fixing unit, the power supply to other than the fixing unit is suppressed to start the fixing unit, and after the startup, the AC power supplied to the fixing unit is temporarily shut off or suppressed, and the second Start the power supply Configured to restart the fixing means after.
[0009]
In order to solve the above-mentioned problem, the present invention turns on the output of the second power supply device when the fixing roller of the fixing unit reaches a predetermined temperature after energizing the fixing unit by turning on the switch unit. Propose that.
[0010]
In order to solve the above-mentioned problem, according to the present invention, the fixing unit includes a third power supply device that includes an induction heating type fixing roller and drives an induction heating coil. Proposes to have a third control unit that is activated in response to an input of an AC power source and controls the temperature of the fixing roller to be a preset temperature.
[0011]
In order to solve the above problems, the present invention includes a third power supply device that drives the fixing unit, and includes at least two temperature detection units that detect the temperature of the fixing roller of the fixing unit. The output of one temperature detection means is input to the first control means and the second control means, the output of the second temperature detection means is input to the third power supply device, and the output of the second power supply device is off. Sometimes when the output of the first temperature detection means detected by the first control means is greater than or equal to a predetermined value, there is a protection means that cuts off the AC power supplied to the fixing means, and is activated by activation of the second power supply device It is proposed that the fixing unit is restarted by outputting a restart signal for restarting the fixing unit from the second control unit to the first control unit .
[0012]
In order to solve the above problem, the present invention provides the second control unit includes a power limiting unit that outputs a signal for limiting the power consumed by the fixing unit, and the fixing unit includes the power limiting unit. It is proposed that the fixing means is driven in response to a signal from.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the vicinity of a power supply unit and a fixing unit in an example of an image forming apparatus according to the present invention. Note that description of a conventional electrophotographic image forming unit and other devices as a whole will be omitted, and the description will focus on the portion related to the present invention.
[0014]
In the image forming apparatus according to the present embodiment, in order to reduce power consumption during standby and to shorten the start-up time from standby to use, the apparatus power source is effectively used to perform standby (energy saving mode). ), At the time of start-up (start-up mode), and at the time of printing (print mode). Specifically, the main power supply of the apparatus is started after the start-up of the fixing apparatus is completed in the start-up mode.
[0015]
In FIG. 1, an AC power source 1 that is a power source of the image forming apparatus branches after being input through a circuit breaker (CB) 2 and a noise filter (NF) 3, and one of them is DC through a main switch (SW 1) 4. A power supply (PSU) 5 is connected. The DC power supply 5 is further branched and connected to the main power supply 8 (second power supply apparatus) via the energy saving power supply 6 (first power supply apparatus) and the main power supply relay 7. The main power supply 8 includes an active filter 9 and a multiple output converter (DC / DC) 10. The output of the energy saving power supply 6 is connected to the energy saving control means 11 (first control means), and the output of the main power supply 8 is connected to the main body control means 12 (second control means). The energy saving control means 11 is connected to an energy saving release switch 13 (release means) for generating an energy saving mode (standby mode) release signal. The energy saving control means 11 and the main body control means 12 are connected so as to be able to exchange signals and data.
[0016]
The other AC power source is connected to fixing means (IH.INV) 20 via power relay 14 (switch means). In the present embodiment, an induction heating type fixing device is used as the fixing means, and a plurality of temperature detection means are provided to ensure safety.
[0017]
The fixing means 20 is roughly composed of a fixing roller 22 having a heating coil 21 therein, a third power supply device (inverter) as other parts, and a fixing roller temperature detecting means. The third power supply device is a component for driving an induction coil as a fixing heater. Note that the pressure roller and the like that are in pressure contact with the fixing roller 22 are not shown.
[0018]
The AC power supplied to the fixing unit 20 is first input to the DC power source (DC / DC2) 25 via the AC detection unit (ACS) 23 and the diode bridge (DB) 24, and the coil 26 and the capacitor 27. It is connected to the resonance circuit of the coil 21 for induction heating and the capacitor 28 through a configured filter, and further connected to the switching element 40 through an overcurrent detection means (OCS) 29. The switching element 40 is connected to the output of the IH control means 30 (third control means).
[0019]
The IH control unit 30 includes a timing circuit 31 that generates an ON signal of the switching element 40, a PWM circuit 32, a drive circuit 33, and the like, and is supplied with power from a DC power supply 25. The timing circuit 31 receives the output of the AC detection means 23 and the voltage applied to the switching element 40. The PWM circuit 32 receives the output control signals via the comparator 34.
[0020]
The outputs of three comparators 35 to 37 are connected to the comparator 34. The input of each comparator is connected to the first comparator (C1) 35 with the second temperature detecting means (inverter thermistor: TH2) 39 attached to the fixing roller 22, and to the second comparator (C2) 36. The overcurrent detection means 29 is connected to the third comparator (C3) 37 and the temperature detection means (TS) 41 of the switching element 40 is connected. A reference voltage is connected to the other input of each comparator.
[0021]
A power limit signal is input from the main body control means 12 through the photocoupler 42 to the PWM circuit 32 described above.
Further, a first temperature detection means (main body thermistor) 38 attached to the fixing roller 22 is connected to the main body control means 12, and further branches from the main body control means 12 to be compared with the comparator (C4) 43 and the comparator. Each of them is connected to the energy saving control means 11 via (C5) 44.
[0022]
In such a configuration, when the main switch 4 is turned on, AC power is input to the energy saving power source 6 (first power supply device) of the DC power source 5 and the energy saving power source 6 is activated. Then, the output of the energy saving power source 6 is supplied to the energy saving control means 11 (first control means), and the energy saving control means 11 is activated. As a result, the image forming apparatus according to the present embodiment enters the energy saving mode that is a standby state.
[0023]
When the energy saving release switch 13 connected to the energy saving control means 11 is pressed in the state of the energy saving mode and an energy saving release signal is input to the energy saving control means 11, the energy saving control means 11 cancels the energy saving mode and shifts to the start-up mode. To do.
[0024]
In the start-up mode, the power relay 14 is turned on and AC power is supplied to the fixing unit 20. As a result, AC power is input to the diode bridge 24 via the AC detection means 23, and DC power rectified by the diode bridge 24 is input to the DC power supply 25. The low voltage power supply, which is the output of the DC power supply 25, is supplied to the IH control means 30 (third control means), the IH control means 30 is activated and the fixing control is started, whereby the fixing means 20 is activated.
[0025]
In the IH control means 30, an ON signal of the switching element 40 is generated so that the output of the comparator 34 input to the PWM circuit 32 becomes a predetermined value, and is output from the drive circuit 33 to the switching element 40. As a result, the switching element 40 starts switching, and a drive current of several tens of kHz flows through the induction heating coil 21 built in the fixing roller 22. For this reason, a magnetic flux interlinking with the fixing roller 22 is generated in the coil 21, and an eddy current flows through a conductor portion of the fixing roller 22, and the fixing roller 22 generates heat due to Joule heat.
[0026]
There is a feedback loop in which the temperature is detected by the second temperature detection means 39 attached to the fixing roller 22 and compared with the reference voltage Vref1 by the first comparator 35, and the difference is input to the PWM circuit 32 via the comparator 34. Since it is configured, the fixing roller 22 is controlled to maintain a predetermined temperature.
[0027]
Since the reference voltage is set so that the first comparator 35 is preferentially controlled with respect to the other comparators among the respective comparators, the fixing roller 22 that is normally the input of the first comparator 35 is set. The temperature is controlled to be a predetermined value.
[0028]
The other comparators 36 and 37 are for generating a protection signal when an abnormality occurs in the fixing means 20, and the second comparator 36 detects an overcurrent of the switching element 40, and the third comparator. In 37, the temperature of the switching element 40 is detected. In any case, the drive signal of the switching element 40 is set to be OFF when there is an abnormality.
[0029]
Further, the temperature of the fixing roller 22 is also detected by the first temperature detection means 38 and is input to the energy saving control means 11 and the main body control means 12, but is detected only by the energy saving control means 11 in the start-up mode. . Although the temperature information of the two systems of the comparator 43 and the comparator 44 is input to the energy saving control means 11, the temperature detection levels of the two systems are set to different values. First, the comparator 43 detects an abnormality, and when the input temperature information of the fixing roller 22 exceeds a preset value, it is determined that the fixing unit 20 is abnormal, and the power relay 14 is turned off. Thus, the supply of AC power to the fixing means is stopped. In addition, the comparator 44 detects a reload that the fixing temperature has been reached.
[0030]
As described above, when the energy saving mode is canceled, the power relay 14 is turned on to activate the fixing unit 20, and only the IH control unit 30 of the fixing unit is used so that the temperature of the fixing roller 22 is set to a preset temperature. Temperature control is performed. At this time, the energy saving control means 11 also monitors the temperature of the fixing roller 22 in parallel to detect an abnormality of the fixing means 20 and perform a protection operation.
[0031]
As described above, when the fixing unit is started up, power is supplied only to a portion necessary for heating the fixing roller 22, and therefore, the limited power input to the image forming apparatus is effectively used to increase the rise time. It can be shortened as much as possible. Further, a safe device can be provided by detecting the fixing roller temperature with two systems.
[0032]
Next, when the energy saving control means 11 detects that the fixing means 20 is activated and the fixing roller 22 has reached a predetermined temperature (reload), the restart means in the energy saving control means 11 (configured by software in this embodiment). Is activated, the power relay 14 is turned off once to cut off the energization to the fixing means 20, and then the main power supply relay 7 is turned on to activate the main power supply 8 (second power supply device). In this case, the main power supply 8 may be started after temporarily suppressing the power consumed by the fixing unit, instead of interrupting the energization of the fixing unit. When a low-voltage power supply is supplied from the main power supply 8 to the main body control means 12, the main body control means 12 is activated, and the power limiting means (configured by software in the present embodiment) in the main body control means 12 is powered via the photocoupler 42. The limit signal is output to the PWM circuit 32 of the fixing unit 20 and the restarting signal of the fixing unit is output to the energy saving control unit 11. As a result, the energy saving control means 11 turns on the power relay 14 again and restarts the fixing means 20. By the operation so far, the image forming apparatus completes the start-up mode and shifts to a print mode in which printing is possible.
[0033]
In the print mode, since the power limit signal is input to the PWM circuit 32 of the IH control means 30, the second width of the ON signal output to the switching element 40 is limited to a value shorter than that in the start-up mode. The temperature is controlled so that the temperature of the fixing roller 22 detected by the temperature detecting means 39 maintains a predetermined value.
[0034]
The above operation will be described with reference to a flowchart.
FIG. 2 is a flowchart showing the overall operation of the image forming apparatus of this embodiment. In this flowchart, when the main switch 4 is turned on, a transition is made to an energy saving mode which is a standby state. In this state, when the energy saving release switch 13 is pressed, the mode is changed to the startup mode, and the fixing unit 20 is heated and started up. When the start-up of the fixing unit is completed, the mode shifts to the print mode and print processing is executed. When printing is completed and a preset condition (for example, when the next print processing operation is not performed within a predetermined time from the end of printing) is reached, the printer returns to the energy saving mode and enters the standby state. Become.
[0035]
FIG. 3 is a flowchart of the energy saving mode.
In this flowchart, when the main switch 4 is turned on, the energy saving power source 6 is activated, and the energy saving control means 11 is activated by this output. As a result, the apparatus enters a standby state until the energy-saving cancel switch 13 is pressed (turned on) by an operator or a signal (a signal from the host machine, a signal from a FAX incoming call, etc.) in order to perform a copy or print process. When the energy saving cancel switch 13 is turned on, the energy saving mode is canceled and the next startup mode is entered. When the start-up of the fixing unit is completed, the print mode is entered.
[0036]
FIG. 4 is a flowchart of the start-up mode.
In this flowchart, when shifting from the energy saving mode to the start-up mode, the energy saving control means 11 starts a temperature detection process (FIG. 5) which is an interruption process. This process continues until the main switch 4 is turned off after activation. After starting the temperature detection process, the power relay 14 is turned on to start the fixing unit 20. As a result, the fixing roller 22 is heated. Next, when the energy saving control means 11 detects that the temperature of the fixing roller 22 has risen to a predetermined temperature (for example, 185 ° C.) and reloaded, the restarting means in the energy saving control means is activated to turn off the power relay 14 once. As a result, the supply of AC power to the fixing means 20 is cut off and the fixing unit 20 is turned off. Next, the main power supply relay 7 is turned on to activate the main power supply 8, whereby the main body control means 12 is activated. Then, the power limiting unit in the main body control unit is activated and outputs a power limiting signal to the IH control unit 30 of the fixing unit. Further, by outputting a restart signal to the energy saving control means 11, the energy saving control means 11 turns on the power relay 14, restarts the fixing means 20, and the fixing means 20 has a power that is limited compared to when it is started up. Control the temperature with. When start-up is completed, the next print mode is entered.
[0037]
FIG. 5 is a flowchart of temperature detection processing that is started when the startup mode is shifted to the energy saving mode.
As shown in this flowchart, in this process, an abnormality in the temperature of the fixing roller 22 is monitored (detected), and in the case of an abnormality (for example, when the temperature is 220 ° C. or higher), the power relay 14 is turned off by an interruption process. Then, the energization to the fixing unit 20 is cut off. Thereafter, an abnormality detection signal is transmitted from the energy saving control means 11 to the main body control means 12, and the main body control means 12 performs an abnormality process (for example, display of an abnormal state).
[0038]
FIG. 6 is a flowchart of the print mode.
In this flowchart, when the transition is made from the energy saving mode to the start-up mode and the start-up mode ends and printing is possible, print processing for performing copying or printing is executed. When the print process is completed and the set conditions are satisfied, the mode shifts to the energy saving mode.
[0039]
As described above, in the present embodiment, since the energy saving mode is shifted to the print mode through the startup mode, the limited power input to the image forming apparatus is effectively utilized, and the standby mode is set. It is possible to provide an energy-saving image forming apparatus that has a short rise time from printing to printing.
[0040]
Specifically, in start-up mode, the power consumption in the devices other than the fixing unit can be reduced to increase the distribution of the input power to the fixing unit. The entire image forming apparatus is activated after the power supplied to the means is returned to the normal distribution. That is, power is supplied only to the minimum necessary for heating the fixing roller, the fixing device is started up in a short time, and the entire image forming apparatus is started up after the fixing start-up is completed.
[0041]
In addition, after the start-up, the AC power supplied to the fixing means is temporarily shut off (or suppressed) and restarted to start the main power. Overlap with inrush current due to charging of a circuit and a secondary circuit capacitor (not shown) can be prevented, and the rise time can be shortened without increasing the power capacity of the image forming apparatus.
[0042]
As mentioned above, although this invention was demonstrated by embodiment of illustration, this invention is not limited to the said embodiment. For example, the fixing unit is not limited to the induction heating method, and the present invention can be applied to a fixing device using a halogen heater or a fixing device such as a resistance (surface) heat generation method.
[0043]
【The invention's effect】
As described above, according to the image forming apparatus of the present invention, the second power supply device (main power supply) is turned on after the switch means (power relay) is turned on by starting the fixing means by turning on the release means (energy saving release switch). Since it starts up, it is possible to reduce the power consumption in parts other than the fixing unit and effectively use the limited power input to the image forming apparatus to increase the distribution of the input power to the fixing unit, and in a short time Thus, it is possible to provide an image forming apparatus with a low waiting time by starting up the apparatus.
[0044]
According to the second aspect of the present invention, it is possible to provide an image forming apparatus that consumes less power during standby and has a short rise time.
According to the third aspect of the present invention, it is possible to start up the fixing device by supplying power only to the minimum necessary for heating the fixing roller, and to shorten the rising time of the fixing unit.
[0045]
According to the configuration of the fourth aspect, the temperature of the fixing roller can be detected by two systems, and a safe image forming apparatus can be obtained, and duplication with the inrush current associated with the start of the main power supply can be prevented and the power capacity can be increased. In both cases, an image forming apparatus with a short rise time can be provided.
[0046]
According to the configuration of the fifth aspect, the power consumption of the fixing unit can be switched between startup and printing (copying), and the limited power input to the image forming apparatus can be used effectively, and from standby. An image forming apparatus having a short rise time until printing (copying) is possible can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the vicinity of a power supply unit and a fixing unit in an example of an image forming apparatus according to the present invention.
FIG. 2 is a flowchart showing an overall operation in the present embodiment.
FIG. 3 is a flowchart of an energy saving mode in the present embodiment.
FIG. 4 is a flowchart of a startup mode in the present embodiment.
FIG. 5 is a flowchart of temperature detection processing that is started when a transition is made from a startup mode to an energy saving mode in the present embodiment.
FIG. 6 is a flowchart of a print mode in the present embodiment.
[Explanation of symbols]
1 AC power supply 4 Main switch 6 Energy-saving power supply (first power supply)
8 Main power supply (second power supply)
11 Energy saving control means (first control means)
12 Main body control means (second control means)
13 Energy-saving release switch (release means)
14 Power relay (switch means)
20 Fixing means 21 Induction coil 22 Fixing roller 30 IH control means (third control means)
38 Main body thermistor (first temperature detection means)
39 Inverter thermistor (second temperature detection means)

Claims (5)

A first power supply device to which AC power is supplied when the power switch of the device main body is turned on, first control means that is activated by the supply of power from the first power supply device, and output from the first control means A second power supply unit that is turned on / off, a second control unit that is activated by the supply of power from the second power supply unit, and a release unit that generates a standby mode release signal that is input to the first control unit And fixing means to which AC power is supplied from the power supply of the main body device via the switch means,
When the fixing unit is turned on by turning on the release unit and the fixing unit is activated, the fixing unit is activated by suppressing power supply to other than the fixing unit, and is supplied to the fixing unit after the activation. An image forming apparatus , wherein the AC power supply is interrupted or suppressed, and the fixing unit is restarted after the second power supply device is started . 2. The output of the second power supply device is turned on when the fixing unit is energized when the switch unit is turned on and then the fixing roller of the fixing unit reaches a predetermined temperature. Image forming apparatus. The fixing means includes an induction heating type fixing roller and includes a third power supply device that drives an induction heating coil.
The third power supply is activated in response to an AC power input,
The image forming apparatus according to claim 1, further comprising a third control unit that controls the temperature of the fixing roller to be a preset temperature. A third power supply device for driving the fixing unit;
At least two temperature detection means for detecting the temperature of the fixing roller of the fixing means are provided, and the output of the first temperature detection means is input to the first control means and the second control means, and the second temperature detection means Input the output to the third power supply;
Protection means for cutting off the AC power supplied to the fixing means when the output of the first temperature detection means detected by the first control means is greater than or equal to a predetermined value when the output of the second power supply is off; ,
The fixing unit is restarted by outputting a restart signal for restarting the fixing unit to the first control unit from the second control unit started by starting the second power supply device. The image forming apparatus according to claim 1, wherein the image forming apparatus is characterized. The second control unit includes a power limiting unit that outputs a signal for limiting the power consumed by the fixing unit, and the fixing unit applies a pulse to energize the induction heating coil in accordance with a signal from the power limiting unit. and limits the width, image forming apparatus according to claim 1 or 4.

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