JP2005165143A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of use of power of an image forming apparatus by suppressing the maximum power consumption of the image forming apparatus and to prevent delay in starting of the image forming apparatus at the same time. <P>SOLUTION: An electrophotographic image forming apparatus has a first mode in which copying is possible, and a second mode for copying standby. A fixing means is provided with a first fixing roller with a single heat source or second fixing roller with two or more heat sources with different power consumption and a pressure roller provided with a heat source. A CPU9 of a power source control part 4, in the first mode, controls a fixing control part 11 and an output control part 7 so that, when a temperature sensor 10 of fixing means is at a prescribed temperature, power source is supplied to the first fixing roller or the second fixing roller and the pressure roller and power source is not supplied to a heat retention means, and when the temperature sensor 10 exceeds the prescribed exceeded, power source is supplied alternative to a heat source of the maximum power consumption of the first fixing roller or of the second fixing roller and the pressure roller and power source is supplied to the heat retention means. In the second mode, the CPU9 controls the fixing control part 11 and the output control part 7 so that the power source is not supplied to the first fixing roller or the second fixing roller and the pressure roller and the power source is supplied to the heat retention means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to image formation that suppresses the maximum power consumption between a means for fixing an image formed by electrophotography to a transfer material by thermocompression bonding and a heat retention means for preventing dew condensation on the image forming component and dehumidifying the transfer material. Relates to the device.

  In a digital copying machine, if there is a difference between the temperature of the components of each part of the copying machine and the operating environment temperature of the copying machine, condensation occurs on the components and causes various failures. For this reason, the digital copying machine includes various heaters (heating sources) in the copying machine main body. These heaters are an optical system heater in the scanner unit, a charging system heater in the electrophotographic process unit, a paper feed system heater in the paper feed unit, and the like. The optical heater eliminates the occurrence of image defects due to the prevention of condensation on mirrors and lenses, and the charging heater eliminates the occurrence of image defects due to the prevention of condensation on the charging roller and drum constituting the charger, and the occurrence of jamming due to winding of the transfer paper. To do. In addition, the paper feed system heater eliminates condensation on the paper feed cassette in the paper feed section and paper jams due to the moisture content of the transfer paper set in the paper feed cassette, thereby eliminating transfer paper transportability and transfer rate reduction. .

  In recent years, there has been a strong demand for higher performance in digital copiers, such as quick start-up of copiers after turning on the power switch to shorten the first copy time, and improving the quality of formed images. There is a strong demand to reduce energy consumption and minimize energy consumption.

2. Description of the Related Art Conventionally, as an invention relating to prevention of condensation in a digital copying machine, a power switch portion of a power supply line that supplies power to the digital copying machine, a load system line that supplies power to the digital copying machine body, an optical condensation heater, and a charging drum heater Then, it is possible to branch to a heater system line that supplies power to the transfer paper heater, and the power supply path is changed by switching the switch. A timer is provided in the power switch section, and the switch is switched to the heater system according to the on time and off time of the timer, and power is supplied to the heater system to prevent dew condensation of the devices, and the moisture content of the transfer paper An invention for dehumidification is known (see Patent Document 1).
JP-A-9-269706

  In the invention described in Patent Document 1, the power supply to the optical dew condensation heater, the charging drum heater, and the transfer paper heater is performed all at once in a certain time zone by switching the timer. Since it is performed at any time, the user resets the timer and returns the switch to the original state to perform copying when copying is desired. However, in order to prevent the dew condensation of the equipment and to dehumidify the moisture content of the transfer paper, the dew condensation prevention heater and the dehumidification heater are always operated, that is, the dew condensation prevention heater and the dehumidification heater are always turned on. It is desirable that the power consumption of the dew condensation prevention heater and the dehumidification heater be turned on and off as in the invention of Patent Document 1, and there is a problem that the maximum power consumption increases. On the other hand, as mentioned above, it is required to start up the copying machine in a short time. For this reason, a heater with high power consumption is used as a fixing heater, and a heater for preventing condensation, etc., which is always operating is also turned on. If this is done, the maximum power consumption will inevitably increase. Therefore, the amount of power used increases.

  The present invention has been made in view of such a situation, and a first object is to suppress an increase in the maximum power consumption of the image forming apparatus, so that the start-up of the image forming apparatus is not delayed at that time. The second object is to do this, and the third object is to reduce the power consumption of the image forming apparatus.

  According to a first aspect of the present invention, there is provided an image forming unit for outputting an image, a first heating unit for dehumidifying a predetermined part of the image forming unit, a second heating unit including at least a fixing heater, and the first An image forming apparatus, comprising: an operation signal of the second heating unit as an input, and a control unit configured to control the operation of the first heating unit based on the output of the operation signal.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the image forming apparatus includes a first mode capable of forming an image and a second mode which is an image formation standby mode, and the control unit is configured to perform the second mode. Then, during the transition from the second mode to the first mode, the operation signal of the second heating unit is input as an input during the transition from the second mode to the first mode. An image forming apparatus that controls operation of a first heating unit.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the second heating unit includes a plurality of heaters including a fixing heater, and the control unit includes a second heating unit. The image forming apparatus is characterized in that when the operation signals from a plurality of heaters are input simultaneously, the power supply to the first heating unit is cut off.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the first or second aspect, the second heating unit includes a plurality of heaters including a fixing heater, and the control unit includes a second heating unit. When the operation signal of the heating means that consumes the maximum power is input, when the operation signal of any of the other second heating means is input, the energization to the first heating means is controlled. The image forming apparatus is characterized by the above.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects of the present invention, the image forming apparatus further comprises means for detecting a connection state of an optional peripheral device, and the control means is configured to detect the detected option peripheral device. An image forming apparatus comprising: means for controlling power supply to a heating source of a first heating means based on a connection state.

According to the present invention, it is possible to suppress the increase in the maximum power consumption of the image forming apparatus and to operate the dehumidifying and heating means for as long as possible while reducing the power consumption, and from the image forming standby mode (energy saving mode). At the time of switching to a mode capable of image formation, that is, during the transition (when the image forming apparatus is started up), power can be preferentially supplied to the fixing heater, so that the start-up can be accelerated.
In addition, when an optional peripheral device is connected to the image forming device, the maximum power consumption can be suppressed only by processing on the device body side, even when DC power is required during the initial operation of the optional peripheral device. The influence on the rise time of the fixing means can be eliminated.

First, a digital copying machine using an electrophotographic process system in which the present invention is implemented will be described.
FIG. 1 is a central sectional view schematically showing an internal configuration of a digital copying machine main body in which the present invention is implemented. The engine of the digital copying machine includes a scanner unit 50 that reads a document, a writing unit 60 that forms a latent image of a read image on a photoreceptor 71, an electrophotographic process unit 70 that develops the latent image to form a toner image, and a toner A fixing unit 80 for fixing the image and a paper feeding unit 90 for storing and transporting the transfer paper 91 are provided.

  The scanner unit 50 that reads the document image is provided with a lamp 34 that illuminates the document, and the scanning reflected light of the document by the lamp is focused on the CCD 54 via the mirror 35, the lens 53, etc., and the document image is converted into an electric signal. Converted. This electrical signal is input to an image data processing unit (not shown) to generate image data.

  The writing unit 60 includes two laser diodes (LDs) that output laser light based on the image data processed by the image data processing unit, a polygon scanner equipped with a polygon mirror that deflects the laser light at a constant angular velocity, and a constant angular velocity deflection. Optical element having an fθ characteristic for correcting the laser beam so that the laser beam is deflected at a constant velocity on a photoreceptor 71 of an electrophotographic process unit 70, which will be described later, and a synchronization detection unit for generating a synchronization signal for each line (whichever (Not shown). The plurality of LDs may be an LD array that outputs a plurality of outputs in one package. Further, a writing unit using one laser may be used.

  The electrophotographic process unit 70 is a part that forms a toner image and transfers the toner image onto a transfer sheet 91. A process device is provided around the photoreceptor 71. That is, around the photosensitive member 71, a charging unit 72, a magenta developing unit 3M, a cyan developing unit 3C, a yellow developing unit 3Y, a color developing unit group 73 including a black developing unit 3K, a cleaning device 74, and a static elimination lamp 75 are arranged. Has been. Further, a belt-like intermediate transfer member 76 is disposed so as to face the photoreceptor 71, and a primary transfer unit 77 is disposed inside the intermediate transfer member 76. A secondary transfer device 78 and a cleaning device 79 are disposed around the outer periphery of the intermediate transfer member 76.

  In the electrophotographic process unit 70, the writing unit 60 scans the uniformly charged photoconductor 71 with a laser beam of image data to form a latent image on the photoconductor 71, and further, a magenta developing unit 3M, A toner image is formed by developing with the cyan developing unit 3C, yellow developing unit 3Y, and black developing unit 3K, and the toner image is transferred to the intermediate transfer member 76 by the primary transfer unit 77. The magenta developing unit 3M, the cyan developing unit 3C, the yellow developing unit 3Y, and the black developing unit 3K contain toners of different colors (magenta, cyan, yellow, and black), respectively. In the case of forming a single color image, the toner image transferred to the intermediate transfer body 76 is transferred as it is to the transfer paper by the secondary transfer device 78, but in the case of forming a full color image, magenta, cyan, Toner images individually formed with four types of toners of yellow and black are superimposed on the intermediate transfer member 76 and then transferred onto a transfer sheet by a secondary transfer unit 78. The photosensitive member 71 and the intermediate transfer member 76 are cleaned by the respective cleaning devices 74 and 79 after the primary transfer and the secondary transfer.

  The paper supply unit 90 stores a transfer sheet 91 on which a toner image is transferred, and conveys the transfer sheet 91 to the secondary transfer unit 78. In order to match the leading edge of the paper and the leading edge of the image, the paper is conveyed at a timing by a registration roller (not shown).

  The fixing unit 80 includes a fixing roller and a pressure roller (not shown) in order to fix the toner image transferred onto the transfer paper 91 by the secondary transfer unit 78. The fixing roller has a resistance heating element (heater) as a heat source, and has only a main heater or a main heater and an auxiliary heater as will be described later. The pressure roller may have a heater. When the transfer paper 91 is conveyed between the intermediate transfer body 76 and the secondary transfer device 78, the toner image on the intermediate transfer body 76 is transferred to the transfer paper 91 by the secondary transfer device 78. Is fed between the fixing roller and the pressure roller of the fixing unit 80.

  The case where a toner image is transferred in the order of magenta, cyan, yellow, and black to form a color image will be described. When the controller is instructed to start image formation, the polygon scanner starts rotating and drives the main motor. Then, the photoreceptor 71 and the fixing roller start to rotate. By writing the bitmap data developed in the control unit as laser light on the photoconductor 71 uniformly charged in advance by a charger, a latent image is formed, and the latent image is visualized with toner. Forming a color image. First, magenta component data is output as laser light. An electrostatic latent image is formed on the photoreceptor 71 by the laser light, and magenta toner is attached to the electrostatic latent image. The magenta toner image is transferred to the intermediate transfer member 76. Subsequently, cyan component data is output as laser light. An electrostatic latent image is formed on the photoreceptor 71 by this laser light, and cyan toner is attached to the electrostatic latent image. The cyan toner image is transferred so as to be superimposed on the magenta toner image on the intermediate transfer member 76. Subsequently, the yellow component data is output as laser light. An electrostatic latent image is formed on the photoreceptor 71 by this laser light, and yellow toner is attached to the electrostatic latent image. The yellow toner image is transferred so as to be superimposed on the magenta and cyan toner images on the intermediate transfer member 76. Furthermore, an electrostatic latent image is formed on the photoreceptor 71 by outputting black component data as laser light. Black toner is attached to the electrostatic latent image, and the black toner image is superimposed on the magenta, cyan, and yellow toner images on the intermediate transfer member 76. As a result, toner images of four colors of magenta, cyan, yellow and black are superimposed on the intermediate transfer member 76. The four color toner images are transferred onto the transfer sheet 91 at a time, and conveyed to the fixing unit 80 for fixing processing.

  When performing double-sided printing, after the transfer paper printed on one side passes through the fixing device 80, it is transported to the double-sided printing unit by a transport path switching means (not shown), and the transfer paper is reversed and transported to the registration roller unit again. To do. The registration roller is driven with good timing in accordance with the leading edge of the image, the image is transferred to the back side printed on one side, the image is fixed by the fixing unit 80, and conveyed to the paper discharge unit.

  Although not shown in FIG. 1, the digital copying machine configured as described above includes an optical system heater inside the scanner unit, a charging / photosensitive body heater inside the electrophotographic process unit 70, and a dehumidifying heater that prevents moisture absorption of the transfer paper, In addition, a power supply device is installed to supply power to each part of the heater and the copying machine.

Next, this power supply device will be described.
FIG. 2 is a schematic block diagram of a power supply device to various heaters of the digital copying machine according to the embodiment of the present invention.
The electric power supplied from the commercial AC power source 1 is supplied to the DC power source 3 via the main switch 2 of the digital copying machine, and is supplied from the front of the main switch 2 to the dehumidifying heater 6 via the relay device 5. The The DC power supply unit 3 converts AC 100V into DC power supply + 24V, + 5VE, etc., and supplies + 24V to the relay device 5 under the control of the power supply control unit 4 and the output control unit 7. The power supply control unit 4 is equipped with an AD converter 8 and a CPU 9, and the AD converter 8 AD converts the output of a temperature sensor (thermistor) of a fixing unit (not shown) here. The CPU 9 recognizes the AD-converted sensor output, controls the fixing control unit 11 with reference to a preset temperature, and the fixing control unit 11 controls power supply to the heating source of the fixing unit. Further, the CPU 9 controls the output control unit 7 in conjunction with this supply, and the control output unit 7 controls the power supply to the relay device 5.

  When the energy-saving mode is set from the operation unit (not shown), the power control unit 4 turns on the heating source of the fixing unit and other operation units when the digital copying machine is not used for a predetermined time after the digital copying machine starts up. It is possible to enter an energy saving mode in which power supply is suspended.

  As described above, the fixing unit of the digital copying machine includes a fixing roller that fixes the toner of the transfer paper and a pressure roller that presses the transfer paper from the back side. However, in the case of a high-speed machine or a color machine, since a large amount of heat is required for fixing, a heater may be provided on both the fixing roller and the pressure roller. In this case, two types of heaters for the fixing roller, the main heater and the auxiliary heater, are used from the viewpoint of energy saving, and both heaters are operated when the fixing unit starts up. When the temperature reaches a predetermined temperature, the main heater alone maintains a constant temperature. To be done.

  In order to prevent dew condensation on the components of the digital copying machine, a dew condensation prevention heater and a dehumidifying heater are provided to remove moisture from the paper feed tray for storing the transfer paper and the transfer paper itself. This humidity is different from the case of dew condensation that occurs when it is cold or the like, and it is desirable to remove it constantly. For this reason, it is particularly desirable to keep the dehumidification heater always in operation. However, it is necessary to minimize the power supplied to the various heater systems in order to reduce the maximum power consumption and also to reduce the power consumption from the viewpoint of energy saving. Therefore, the present invention receives as input the operation status (ON, OFF) signals of a fixing roller heating heater (hereinafter abbreviated as a fixing heater) and a pressure roller heater (hereinafter abbreviated as a pressure heater) of the fixing unit, A logic circuit that uses the output as an operation signal for a heater for heating the dehumidification roller (hereinafter abbreviated as a dehumidification heater) is configured so that the maximum power consumption does not exceed a predetermined value by controlling the fixing heater and the pressure heater on and off. Controls the operation of the dehumidifying heater.

(Embodiment 1) In this embodiment, when the fixing unit has only a fixing heater, power supply control of the dehumidifying heater is performed.
FIG. 3 is a diagram for explaining a control circuit of the dehumidifying heater when the fixing unit has only the fixing heater. In FIG. 3A, 31 is an inverter circuit (NOT circuit). The input terminal of the NOT circuit 31 receives an operation status signal of the fixing heater in conjunction with the heater control of the fixing control unit 11 by the CPU 9. Since the ON signal is received when the fixing unit is up, the output terminal becomes the OFF signal. The output terminal of the NOT circuit 31 is connected to the output control circuit 7, and the output control circuit 7 is actually composed of a switching circuit by a transistor 7a. The transistor 7a is biased so that it is turned on when no input signal is supplied and turned off when an input signal is supplied. Note that D1 is a diode for preventing the back-up of the relay device.

  Here, the relay device 5 is a so-called break contact type relay, and the contact breaks (opens) when there is an input signal, and does not break (closes) when there is no input signal. Therefore, since the power 24V is supplied when the fixing unit is up, the relay device 5 is opened and the commercial power 1 is not supplied to the dehumidifying heater 6. That is, the dehumidifying heater 6 is in a non-energized state.

  On the other hand, when the energy saving mode is activated and the fixing unit is at rest, the input terminal of the NOT circuit 31 receives the off signal in conjunction with the heater control of the fixing control unit 11, so the output terminal is set to the on signal. Accordingly, since the input signal is supplied to the transistor 7a, the transistor 7a is turned off, and the power supply 24V is not supplied to the relay device 5. Therefore, the relay device 5 is closed and the commercial power source 1 is supplied to the dehumidifying heater 6. That is, the dehumidifying heater 6 is energized and dehumidifies.

  FIG. 3B is an explanatory diagram of the energization operation of the dehumidifying heater. When the fixing heater is OFF, the dehumidifying heater is ON, and when the fixing heater is ON, the dehumidifying heater is OFF.

  (Embodiment 2) In this embodiment, when the fixing unit has a fixing heater and a pressure heater, power supply control of the dehumidifying heater is performed.

FIG. 4 is a diagram for explaining a control circuit of the dehumidifying heater when the fixing unit includes a fixing heater and a pressure heater. In FIG. 4A, 32 is a NAND circuit. The NAND circuit 32 has two input terminals for inputting operation status signals of the fixing heater and the pressure heater from the power controller 4, and the output terminal is connected to the output controller 7. The configurations of the output control unit 7 and the relay device 5 are the same as those in the first embodiment.
When both the fixing heater and the pressure heater of the fixing unit are raised, the two input terminals of the NAND circuit 32 receive the ON signal, so that the output terminal becomes the OFF signal. Accordingly, since the power 24V is supplied to the relay device 5, the relay device 5 contacts are opened, and the commercial power source 1 is not supplied to the dehumidifying heater 6. That is, the dehumidifying heater 6 is in a non-energized state.

  When both the fixing heater and the pressure heater of the fixing unit are not raised, the input terminal of the NAND circuit 32 receives the off signal in conjunction with the heater control of the fixing control unit 11, so the output terminal is the ON signal. Become. Therefore, since the power source 24V is not supplied to the relay device 5, the relay device 5 contacts are closed, and the commercial power source 1 is supplied to the dehumidifying heater 6 to perform dehumidification.

  When either the fixing heater or the pressure heater is not up, the input terminal of the NAND circuit 32 receives the on and off signals in conjunction with the heater control of the fixing controller 11, so the output terminal is on. Signal. Therefore, since the power source 24V is not supplied to the relay device 5, the contact of the relay device 5 is closed, and the commercial power source 1 is supplied to the dehumidifying heater 6 to perform dehumidification.

  FIG. 4B is an explanatory diagram of the energization operation of the dehumidifying heater. The dehumidification heater is ON when the fixing heater and the pressure heater are both OFF, the dehumidification heater is ON when the fixing heater is OFF and the pressure heater is ON, the dehumidification heater is ON when the fixing heater is OFF and the pressure heater is OFF, When both the fixing heater and the pressure heater are ON, the dehumidifying heater is energized so that it is OFF.

FIG. 5 is a diagram illustrating the operation timing of power supply control of the dehumidifying heater when the fixing unit includes a fixing heater and a pressure heater. The power supply operation will be described based on this timing diagram.
In FIG. 5, in the state where the main SW is OFF, since there is no power supplied to the relay device 5, the relay contact is closed (contacted), and power is supplied to the dehumidifying heater 6 (state a).
When the main SW is turned on, the DC power supply unit 3 generates + 24V power. Since the CPU 9 does not enter the energy saving mode immediately after the main SW is turned on, the CPU 9 compares the detected temperature of the fixing temperature sensor 10 (the temperature of the fixing unit) with the first set temperature 2 in the rising process, and the detected temperature is the set temperature. If lower than 2, the fixing controller 11 turns on the fixing heater and the pressure heater, and the output controller 7 starts energization (+ 24_RELAY supply) to the relay device 5 to open (separate) the relay contact. Then, the power supply to the dehumidifying heater 6 is cut off (state b). Since it takes some time until the contact of the relay device is opened, the fixing heater and the pressure heater are operated simultaneously after several hundred msec.
When the temperature of the fixing unit reaches the set temperature 2, the energization time to the fixing heater and the pressure heater is switched alternately, for example, every second, and control is performed so that simultaneous energization is not performed. In this state, the power of one heater can be supplied to another load. At this time, the rating (maximum current value) of the household commercial power supply is not exceeded. After the fixing unit temperature reaches the set temperature 2, the CPU 9 stops energization (+ 24_RELAY supply) to the relay device 5, closes (contacts) the contact of the relay device 5, and supplies power to the dehumidifying heater 6. Start (state c). During this time, the temperature of the fixing unit further rises, and when the final set temperature 1 is reached, copying is possible. Even in this state, the alternate energization is maintained, and the energization to the relay device 5 is stopped and the power supply to the dehumidifying heater 6 is continued (state d).

  If copying is not performed for a predetermined time in the copy enabled state, the CPU 9 shifts the digital copying machine to the energy saving mode. In this state, the temperature of the fixing unit gradually decreases from the set temperature 2 to the set temperature 2 or lower.

When the energy saving mode is canceled when the temperature of the fixing unit is higher than the set temperature 2, the power supply control of the fixing unit is controlled so that the energization of the fixing heater and the pressure heater is alternately energized. The energization state of the dehumidifying heater 6 is maintained (state e).
When the energy saving mode is canceled when the temperature of the fixing unit is lower than the set temperature 2 (state f), the power supply control unit 4 operates the fixing heater and the pressure heater at the same time, enabling copying as soon as possible. Control to return to. For this reason, the rating (maximum current value) of the household commercial power supply may be exceeded. Therefore, power supply to the dehumidifying heater 6 is temporarily stopped, and power supply control to the fixing unit is started (state b ′). In this case as well, as in the state b, since it takes some time until the contact of the relay device 5 is opened, the fixing heater and the pressure heater are operated simultaneously after several hundred msec. Thereafter, the state shifts to the above-mentioned state c and state d. When the main SW is disconnected, no power is supplied to the relay device 5, so the contact of the relay device 5 is closed and the dehumidifying heater 6 is in a power supply state (state a).

  FIG. 6 is a diagram illustrating a control procedure of power supply control of the dehumidifying heater. The control procedure will be described based on this figure. When the digital copying machine is not in operation and is simply connected to a commercial power source, the dehumidifying heater 6 is on (S1). When the main SW2 is turned on, the CPU 9 checks whether or not the mode is shifted to the energy saving mode (S2), and when not shifted to the energy saving mode, the dehumidifying heater 6 is turned off (S3) and the fixing unit fixing heater And it is checked whether the pressure heater is operating at the same time (S4). When simultaneously operating (S4, YES), the above check is performed until not simultaneously operating, that is, until the set temperature 2 is exceeded. At the same time, when not operating (S4, NO), power is supplied to the dehumidifying heater and the heater is turned on (S5). Then, the CPU 9 returns to checking whether the digital copying machine has shifted to the energy saving mode. When the mode is shifted to the energy saving mode in step S2, the dehumidifying heater is turned on.

  A series of processing procedures for executing the power supply control operation to the dehumidifying heater of the above-mentioned digital copying machine is described as a computer program, and this program is stored in an arbitrary recording medium such as a flexible disk, CD-ROM, DVD-ROM or the like. The power supply control operation according to the present invention can be easily performed by recording the data and reading it from the computer of the digital copying machine.

  (Embodiment 3) In this embodiment, when the fixing unit includes a fixing heater a (main heater), a fixing heater b (auxiliary heater), and a pressure heater, power supply control of the dehumidifying heater is performed.

  FIG. 7 is a diagram for explaining a dehumidifying heater control circuit when the fixing unit includes a fixing heater a (main heater), a fixing heater b (auxiliary heater), and a pressure heater. Is a NAND circuit. The NAND circuit 33 has three input terminals for inputting the operation status signals of the fixing heater a (main heater), the fixing heater b (auxiliary heater), and the pressure heater from the power supply controller 4, and the output terminal is an output controller. 7 is connected. In addition, since the structure of the output control part 7 and the relay apparatus 5 is the same as that of the case of Embodiment 1, description is abbreviate | omitted in this figure.

FIG. 7B is an explanatory diagram of the energization operation of the dehumidifying heater. When energy saving mode is entered and fixing heater a, fixing heater b, and pressure heater are all OFF, dehumidifying heater is ON (case 0), and when energy saving mode is canceled and the fixing unit is starting up, fixing heater a, fixing The heater b and the pressure heater are all turned on, and the dehumidifying heater is turned off (case 7).
After the fixing unit rises and reaches a predetermined temperature, operation control is performed so that one or two of the fixing heater a, the fixing heater b, and the pressure heater are always stopped (case 1 to case 6). . That is, fixing heater aON, fixing heater bOFF, pressure heater OFF (case 1), fixing heater aOFF, fixing heater bON, pressure heater OFF (case 2), fixing heater aON, fixing heater bON, pressure heater OFF (case) 3) Fixing heater aOFF, fixing heater bOFF, pressure heater ON (case 4), fixing heater aON, fixing heater bOFF, pressure heater ON (case 5), fixing heater aOFF, fixing heater bON, pressure heater ON ( Case 6). In any of these cases, the dehumidifying heater is turned on to perform dehumidification.

  When the power consumption of the fixing heater a is 750 watts (W), the power consumption of the fixing heater b is 150 W, the power consumption of the pressure heater is 400 W, and the dehumidifying heater (total of multiple units) is 30 W, the maximum is 1300 W Never exceed.

  FIG. 8 is a diagram illustrating the operation timing of the power supply control of the dehumidifying heater when the fixing unit includes the fixing heater a, the fixing heater b, and the pressure heater. The power supply operation will be described based on this timing diagram. Even in this case, the basic part is the same as the operation in the case of having two heaters described with reference to FIG.

  In the state a, the state e, and the state f, the dehumidifying heater 6 is energized with all three heaters turned off. In the state b, the power supply to the dehumidifying heater 6 is cut off with all three heaters turned on. The state d is a state in which the auxiliary fixing heater b is always turned off and operates only when the fixing heater a and the pressure heater are alternately required, and is basically the same as the case where two heaters are configured. .

In the case of the state c, unlike the case of the two heaters, the state is divided into a state c1 and a state c2.
A set temperature 3 is provided between the set temperature 1 and the set temperature 2. Each temperature has a relationship of set temperature 1> set temperature 3> set temperature 2.

  The state c1 is a state in which the temperature rises from the set temperature 2 to the set temperature 3, and the timing at the boundary with the state b is the timing at which the load of the DC system starts to be moved. At this timing, the temperature of each roller of the fixing unit is made uniform. In order to achieve this, the rotation of the conveyance motor that drives the fixing unit is started. The state c2 is a state in which the temperature rises from the set temperature 3 to the set temperature 1, and the timing at the boundary with the state c1 is a timing at which process control (procone) is started.

  In the state c1, the fixing heater a and the energization of the fixing heater b and the pressure heater are alternately energized. In the state c2 and the state d, the energization of the fixing heater a and the pressure heater is alternately performed. When the heaters b are energized simultaneously, the total power consumption becomes 900 W, and the power consumption including the optional device may exceed the rated power. For this reason, the fixing heater b is controlled at the timing when it operates simultaneously with the pressure heater. In this way, the electric power required by operating the heater of the fixing unit can be suppressed to a maximum of 750 W. However, electric power of an electronic circuit, a relay, etc. that controls energization to the dehumidifying heater is not taken into consideration.

  (Embodiment 4) In this embodiment, when the fixing unit includes a fixing heater a (main heater), a fixing heater b (auxiliary heater), and a pressure heater, the fixing heater a, at least the fixing heater b (auxiliary heater), and Power supply control of the dehumidifying heater is performed so as to stop energization of the dehumidifying heater when any of the pressure heaters is operating. For this purpose, the dehumidifying heater control circuit is composed of a 2-input NAND circuit and an OR circuit.

  FIG. 9 is a diagram for explaining a control circuit for stopping energization to the dehumidifying heater when any one of the fixing heater a and at least the fixing heater b (auxiliary heater) and the pressure heater is operating. ), 34 is a NAND circuit, and 35 is an OR circuit. The operation signal of the fixing heater a is applied to one input end of the NAND circuit 34 in conjunction with the heater control of the fixing control unit 11 by the CPU 9, and the fixing heater b and the pressure heater are input to the input end of the OR circuit 35. An operating signal is applied. The output of the OR circuit 35 is applied to the other input terminal of the NAND circuit 34. The output terminal of the NAND circuit 34 is connected to the output control unit 7 in the same manner as in the above embodiment, and controls the operation of the relay device 5.

FIG. 9B is an explanatory diagram of the energization operation of the dehumidifying heater. The operation of the dehumidifying heater control circuit will be described with reference to FIG.
When the energy saving mode is entered and the fixing heater a, the fixing heater b and the pressure heater are all OFF, the dehumidifying heater is ON (case 0), the fixing unit is started or the energy saving mode is canceled and the fixing unit is starting up At this time, the fixing heater a, the fixing heater b, and the pressure heater are all turned on, and the dehumidifying heater is turned off (case 7). Operation control is performed so that one or two of the fixing heater a, the fixing heater b, and the pressure heater are always stopped (case 1 to case 6). That is, fixing heater aON, fixing heater bOFF, pressure heater OFF (case 1), fixing heater aOFF, fixing heater bON, pressure heater OFF (case 2), fixing heater aON, fixing heater bON, pressure heater OFF (case) 3) Fixing heater aOFF, fixing heater bOFF, pressure heater ON (case 4), fixing heater aON, fixing heater bOFF, pressure heater ON (case 5), fixing heater aOFF, fixing heater bON, pressure heater ON ( Case 6).

  Dehumidifying heater is off when fixing heater a power consumption is 750 watts (W), fixing heater b power consumption is 150 W, pressure heater power consumption is 400 W, and dehumidifying heaters (total of several) are 30 W By doing (Cases 3, 5, and 7), power can be supplied in the range of 900 W to 1300 W, so that the rise of the fixing unit can be accelerated while suppressing the maximum power consumption.

(Embodiment 5) In this embodiment, the fixing unit performs power supply control of the dehumidifying heater from the CPU side according to the operations of the fixing heater and the pressure heater.
When the digital copying machine is equipped with an optional peripheral device other than the main body of the apparatus, the initial operation (initial operation) of the optional peripheral device is entered when the optional peripheral device is turned on or returned from the energy saving mode. The maximum power consumption can be reduced by performing the initial operation of the optional peripheral device after the fixing device is sufficiently heated, but the dehumidification heater can be energized depending on the connection status of the optional peripheral device as a response only to the main unit. If controlled, the peak of power consumption can be suppressed by processing only on the main device side. As a result, the power supply to the dehumidifying heater can be controlled even at the timing required for the initial operation of the optional peripheral device, so that the rise time of the fixing unit is not affected.

  FIG. 10 is a diagram for explaining a circuit for performing power supply control of the dehumidifying heater from the CPU side. In FIG. 10A, 36 is a NAND circuit. The NAND circuit 36 has two input terminals for inputting the operation status signals of the fixing heater and the pressure heater from the power controller 4 and one Enable terminal for controlling the power supply of the dehumidifying heater from the CPU side. Are connected to the output control unit 7. In addition, since the structure of the output control part 7 and the relay apparatus 5 connected to this control part is the same as that of the case of Embodiment 1, description is abbreviate | omitted in this figure.

FIG. 10B is a diagram illustrating a control example of the energization operation of the dehumidifying heater. The operation of the dehumidifying heater control circuit will be described with reference to FIG.
When the fixing unit is started or when the energy saving mode is canceled and the fixing unit is started up and the fixing heater and the pressure heater are ON, the dehumidifying enable is turned on and the dehumidifying heater is turned off (case 7). When the fixing heater and pressurizing heater are OFF when shifting to the energy saving mode, the dehumidifying heater Enable is turned OFF and the dehumidifying heater is turned ON (Case 0).

  In addition, when the fixing heater is ON and the pressure heater is OFF, dehumidification Enable is turned OFF and the dehumidification heater is turned ON (Case 1). When the fixing heater 0FF and the pressure heater are on, dehumidification enable is turned off and the dehumidification heater is turned off (case 2). When the fixing heater is ON and the pressure heater is ON, dehumidification Enable is turned OFF and the dehumidifying heater is turned ON (Case 3). When the fixing heater is OFF and the pressure heater is OFF, dehumidification Enable is turned ON and the dehumidification heater is turned ON (Case 4). When the fixing heater is ON and the pressure heater is OFF, dehumidification Enable is turned ON and the dehumidification heater is turned ON (Case 5). When the fixing heater is OFF and the pressure heater is ON, it is also possible to perform control such as turning ON the dehumidifying heater by turning ON the dehumidifying enable (case 6).

  (Embodiment 6) In this embodiment, when the fixing unit includes a fixing heater a, a fixing heater b, and a pressure heater, the CPU supplies power to the dehumidifying heater according to the operation of the fixing heater a and the fixing heater b. I do.

  FIG. 11 is a diagram for explaining a circuit that performs power supply control of the dehumidifying heater from the CPU side. In FIG. 11A, 37 is a NAND circuit, and 38 is a NOR circuit. The NAND circuit 37 has two input terminals for inputting operation status signals of the fixing heater a and the fixing heater b from the power supply control unit 4, and the NOR circuit 38 has an input terminal for receiving the output of the NAND circuit 37, and a CPU side. 1 has one Enable terminal for controlling the power supply of the dehumidifying heater, and the output terminal is connected to the output controller 7. In addition, since the structure of the output control part 7 and the relay apparatus 5 connected to this control part is the same as that of the case of Embodiment 1, description is abbreviate | omitted in this figure.

FIG. 11B is a diagram illustrating a control example of the energization operation of the dehumidifying heater. The operation of the dehumidifying heater control circuit will be described with reference to FIG.
When the fixing unit is started or when the energy saving mode is canceled and the fixing unit is started up and the fixing heater a and the fixing heater b are ON, the dehumidifying enable is turned ON and the dehumidifying heater is turned OFF (case 7).

  In addition, when the fixing heater is ON and the pressure heater is OFF, dehumidification Enable is turned OFF and the dehumidification heater is turned ON (Case 1). When the fixing heater 0FF and the pressure heater are on, dehumidification enable is turned off and the dehumidification heater is turned off (case 2). When the fixing heater is ON and the pressure heater is ON, dehumidification Enable is turned OFF and the dehumidifying heater is turned ON (Case 3). When the fixing heater is OFF and the pressure heater is OFF, dehumidification Enable is turned ON and the dehumidification heater is turned ON (Case 4). When the fixing heater is ON and the pressure heater is OFF, dehumidification Enable is turned ON and the dehumidification heater is turned ON (Case 5). When the fixing heater is OFF and the pressure heater is ON, dehumidification Enable is turned ON and the dehumidification heater is turned ON (Case 6). When the fixing heater a and the fixing heater b are OFF, the dehumidifying heater Enable is turned OFF and the dehumidifying heater is turned OFF (case 0).

  As described above, the image forming apparatus according to the present invention is useful as an image forming apparatus that suppresses the maximum power consumption, and is particularly suitable for use in a large color image forming apparatus.

FIG. 1 is a central sectional view schematically showing an internal configuration of a digital copying machine main body in which the present invention is implemented. 1 is a schematic block configuration diagram of a power supply device to various heaters of a digital copying machine according to an embodiment of the present invention. It is a figure explaining the control circuit of a dehumidification heater in case a fixing part has only a fixing heater. It is a figure explaining the control circuit of a dehumidification heater in case a fixing part has a fixing heater and a pressure heater. It is a figure which shows the operation timing of the power supply control of a dehumidification heater in case a fixing part has a fixing heater and a pressurization heater. It is a figure which shows the control procedure of the power supply control of a dehumidification heater. It is a figure explaining the control circuit of a dehumidification heater in case a fixing part has the fixing heater a, the fixing heater b, and a pressurization heater. It is a figure which shows the operation | movement timing of the power supply control of a dehumidification heater in case a fixing part has the fixing heater a, the fixing heater b, and a pressurization heater. It is a figure explaining the control circuit which stops the electricity supply to a dehumidification heater, when either fixing heater a and at least fixing heater b and a pressurization heater operate | move. It is a figure explaining the circuit which performs power supply control of a dehumidification heater from CPU side. It is a figure explaining the circuit which performs power supply control of a dehumidification heater from CPU side.

Explanation of symbols

  1 .... Commercial AC power supply, 2 .... Main switch, 3 .... DC power supply unit, 4 .... Power supply control unit, 5 .... Relay device, 6 .... Dehumidification heater, 7 .... Output control unit, 8 .... AD Converter, 9 ... CPU, 10 .... Fusing temperature sensor, 11 .... Fixing controller.

Claims (5)

An image forming unit for outputting an image;
A first heating means for dehumidifying to dehumidify a predetermined part of the image forming unit;
A second heating means including at least a fixing heater;
An image forming apparatus, comprising: an operation signal of the second heating unit as an input, and a control unit that controls the operation of the first heating unit based on the output of the operation signal. The image forming apparatus according to claim 1.
A first mode capable of image formation and a second mode which is an image formation standby mode;
In the second mode, the control means cuts off the energization to the first heating means, and
During the transition from the second mode to the first mode, the operation signal of the second heating unit is input as an input, and the operation of the first heating unit is controlled by the output. Forming equipment. The image forming apparatus according to claim 1 or 2,
The second heating means is a plurality of heaters including a fixing heater, and the control means sends the operation signals from the plurality of heaters of the second heating means simultaneously to the first heating means. An image forming apparatus that cuts off the energization. The image forming apparatus according to claim 1 or 2,
The second heating means is a plurality of heaters including a fixing heater, and the control means is a state in which an operation signal of a heating means that consumes the maximum power among the second heating means is input. An image forming apparatus that controls energization to the first heating means when an operation signal of any of the second heating means is input. The image forming apparatus according to claim 1, wherein:
It has a means to detect the connection status of optional peripherals,
The image forming apparatus according to claim 1, wherein the control means includes means for controlling power supply to the heating source of the first heating means based on the detected connection state of the optional peripheral unit.

Images