JP4420124B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer, a copier, a facsimile machine, or a complex machine thereof, and more particularly to an image forming apparatus capable of controlling a plurality of fans for cooling a main body case.

  In conventional image forming apparatuses such as laser printers and copiers, a photosensitive member is charged, and an electrostatic latent image is formed on the photosensitive member by exposure to light such as a laser or LED, and a developer such as toner. Printing is carried out by transferring the image visualized in (1) onto a recording medium such as paper and heating and fixing it with a fixing device. A plurality of cooling fans are provided in the image forming apparatus so that each apparatus is not adversely affected by heat generated from power supply means, a fixing device, or the like that supplies driving power to each apparatus constituting the image forming apparatus. Is provided.

  However, in the conventional image forming apparatus, since the plurality of fans are driven at full speed while being started or at least during printing, the image forming apparatus can be operated in a quiet environment. There is a problem that the user who uses the fan feels uncomfortable due to the noise caused by the wind noise of the fan.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reducing noise caused by wind noise of a fan.

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention includes a process unit that transfers a developer image that has become prominent by a developer to a recording medium, and the process unit that transfers the image to the recording medium. Fixing means for fixing the developed developer image on the recording medium, power supply means for supplying power to the process means and the fixing means, and cooling the power supply means, the fixing means, and the process means. Cooling in a main body case comprising a main fan, a power fan for cooling the power supply means, a sub fan for cooling the fixing means, the main fan, the power supply fan, and the sub fan. an image forming apparatus comprising a plurality of fans, and a fan control means for controlling the rotational speed of the plurality of fans each independently for performing, the fan system The means operates the sub fan until a predetermined period elapses after printing processing ends or until print data is received, and when one of the power supply fan and the main fan is operated. The other fan is stopped, and each fan is controlled so that its operation state is alternately switched every predetermined period .

According to a second aspect of the present invention, there is provided an image forming apparatus comprising: a process unit that transfers a developer image made remarkable by a developer to a recording medium; and a developer image that is transferred to the recording medium by the process unit. Fixing means for fixing to a recording medium, power supply means for supplying power to the process means and the fixing means, a main fan for cooling the power supply means, the fixing means, and the process means, and the power supply A plurality of fans for cooling the main body case comprising a power supply fan for cooling the means, a sub fan for cooling the fixing means, the main fan, the power supply fan, and the sub fan. And a fan control unit that independently controls the rotational speeds of the plurality of fans, wherein the fan control unit includes the fixing hand. When the control is started so that the temperature of the sub-fan becomes lower than the temperature when printing is performed, the sub fan is operated, and one of the power supply fan and the main fan is operated. The other is stopped, and the respective fans are controlled so that their operation states are alternately switched every predetermined period .

According to a third aspect of the present invention, there is provided an image forming apparatus comprising: a process unit that transfers a developer image made remarkable by a developer to a recording medium; and a developer image that is transferred to the recording medium by the process unit. An image forming apparatus comprising a fixing unit for fixing to a recording medium, wherein the process unit and a power supply fan for cooling a power unit provided to supply power to the fixing unit, and the fixing unit A sub-fan for cooling, a main fan for cooling the power supply means, the fixing means and the process means, a fan control means for independently controlling the rotational speed of each fan, and a fixing means a fixing temperature control means for controlling the temperature, the fan control means, the temperature of the fixing means, a predetermined temperature lower than the temperature when the printing is performed From the first timing when the control is started, the sub fan is operated, the power supply fan is stopped for a predetermined period, and then the control is performed repeatedly for a predetermined period. From the second timing after the period, control is performed so that the main fan is stopped when the power supply fan is operated, and is operated when the power supply fan is stopped, and at a third timing after a predetermined period from the first timing. It stops driving of said fixing means, wherein each stopping power fan and the main fan, have row control to stop the sub fan in a fourth timing after a predetermined time period from the third timing, the fixing temperature The control unit sets the temperature of the fixing unit to a temperature at which printing is performed during a print mode period during which printing is performed. Control is performed so that the temperature is a predetermined temperature lower than the temperature at which printing is performed during the ready mode period starting from the first timing and ending when the third timing or print data is received. However, the control is not performed during the sleep mode period starting from the third timing and ending when the print data is received.

In the image forming apparatus according to the first aspect of the present invention, the fan control unit is configured such that when some of the plurality of fans are operated, the other fans are stopped and the operation states are alternately switched every predetermined period. Each fan can be controlled. Further, when the fan control unit operates the sub fan until a predetermined period elapses after the end of the printing process or until print data is received, and one of the power supply fan and the main fan is operated. The other fan is stopped, and each fan can be controlled so that its operation state is alternately switched every predetermined period. Therefore, noise caused by the wind noise of each fan can be reduced.

In the image forming apparatus according to the second aspect of the present invention, the fan control unit stops the other fans when a part of the plurality of fans is operated, and the operation state is alternately switched every predetermined period. As described above, each fan can be controlled. Further, when the fan control unit starts the control so that the temperature of the fixing unit becomes a predetermined temperature lower than the temperature when printing is performed, the sub fan is operated, and the power supply fan and the main fan are operated. When one of them is operated, the other is stopped, and each fan can be controlled so that its operation state is alternately switched every predetermined period. Therefore, noise caused by the wind noise of each fan can be reduced.

In the image forming apparatus according to the third aspect of the invention, the first timing at which the control of the temperature of the fixing unit is started so that the fan control unit has a predetermined temperature lower than the temperature at which printing is performed. Then, the sub fan is operated, the power supply fan is stopped for a predetermined period, and then the control for operating for a predetermined period is repeatedly performed. From the second timing after the predetermined period from the first timing, the main fan is Control is performed when the power supply fan is stopped and when the power supply fan is stopped, the fixing unit is stopped at a third timing after a predetermined period from the first timing, and the power supply fan and the main fan are stopped respectively. , have row control to stop the sub fan in a fourth timing after a predetermined time period from the third timing, the fixing temperature control means, fixing A ready mode in which the temperature of the stage is controlled to be a temperature at which printing is performed during a print mode period in which printing is performed, and starts at the first timing and ends with reception of print data at the third timing. During the period, the temperature can be controlled to be a predetermined temperature lower than the temperature at which printing is performed. Therefore, compared with the transition from sleep mode to print mode, the transition from ready mode to print mode occurs.
In this case, the temperature of the fixing unit can be easily controlled so as to be the temperature at which printing is performed, and noise caused by wind noise of each fan can be reduced.

  Hereinafter, an embodiment of an image forming apparatus embodying the present invention will be described with reference to the drawings. First, the overall configuration of the laser printer 1 will be described with reference to FIG. FIG. 1 is a central sectional view of a laser printer 1 according to the first embodiment. As shown in FIG. 1, the laser printer 1 includes a feeder unit 4 for feeding a sheet 3 as a recording medium in a main body case 2 in a cross-sectional view, and a printer for printing on a fed sheet 3. An image forming unit 5 is provided. In the laser printer 1, the left hand direction in the figure is the front surface.

  The paper discharge tray 46 is formed with a concave portion on the rear side of the upper surface of the main body case 2 so that the printed sheets 3 can be stacked and held on the upper rear end side of the main body case 2. In addition, a front open portion of the upper surface of the main body case 2 has an open upper surface space for inserting the process cartridge 17, and is vertically moved around a support shaft 54 a provided on the front end side of the paper discharge tray 46. The upper surface cover 54 that rotates is configured to cover the cartridge housing portion 57 that is a space for inserting the process cartridge 17. The position when the upper surface cover 54 is opened is indicated by a two-dot chain line in the figure.

  The paper 3 discharged from the fixing device 18 of the image forming unit 5 provided on the lower rear end side in the main body case is provided on the upper rear end side in the rear portion (right hand side in the figure) in the main body case 2. A paper discharge path 44 is provided so as to draw a half arc in the vertical direction along the back surface of the main body case 2 so as to be guided to the paper discharge tray 46. A roller 45 is provided.

  The feeder unit 4 is provided in the paper feed roller 8 provided at the bottom of the main body case 2, the paper feed tray 6 that is detachably mounted, and the paper feed tray 6, and the paper 3 is stacked and held. The sheet pressing plate 7 presses the sheet 3 against the sheet feeding roller 8 and is provided above one end of the sheet feeding tray 6 and is pressed toward the sheet feeding roller 8 to cooperate with the sheet feeding roller 8 during sheet feeding. The separation pad 9 for separating the sheets 3 one by one, the conveyance roller 11 that is provided at two positions downstream of the sheet feeding roller 8 in the conveyance direction of the sheet 3, and conveys the sheet 3. A paper dust removing roller 10 that contacts each of the rollers 11 via the paper 3 to remove paper dust and transports the paper 3 in cooperation with the transport roller 11, and a transport direction of the paper 3 with respect to the transport roller 11 Of the paper 3 at the time of printing And a registration roller 12 to be adjusted.

  The sheet pressing plate 7 can stack the sheets 3 in a laminated form, and a support shaft 7 a provided at the end far from the sheet feeding roller 8 is supported on the bottom surface of the sheet feeding tray 6. With the support shaft 7a as the center of rotation, the near end is movable in the vertical direction, and is biased toward the paper feed roller 8 by a spring (not shown) from the back side. Therefore, the sheet pressing plate 7 is swung downward against the urging force of the spring with the support shaft 7a as a fulcrum as the amount of stacked sheets 3 increases. The paper feed roller 8 and the separation pad 9 are disposed so as to face each other, and the separation pad 9 is pressed toward the paper feed roller 8 by a spring 13 disposed on the back side of the separation pad 9. .

The feeder unit 4 is provided on the front surface (left hand side in the figure) of the main body case 2 and opens and closes in the front-rear direction (left-right direction in the figure) with the support shaft 14a as a fulcrum. Tray portion 14b that can be moved, and a cover portion configured to support a slide portion (not shown) so as to be slidable relative to the tray portion 14b and to become a part of the main body case 2 when the tray portion 14b is closed. 14c, a manual feed roller 14 for feeding the paper 3 stacked on the tray portion 14b of the manual feed tray 14, and a separation pad 25 for separating the paper 3 one by one. Yes.

  The manual feed roller 15 and the separation pad 25 are disposed so as to face each other, and the separation pad 25 is pressed toward the manual feed roller 15 by a spring (not shown) disposed on the back side of the separation pad 25. During printing, the sheets 3 stacked on the manual feed tray 14 are conveyed to the registration rollers 12 one by one by the rotating manual feed roller 15 and the separation pad 25.

  A low-voltage power supply unit 90 and a high-voltage power supply unit 95 are provided between the image forming unit 5 and the paper feed tray 6, and the low-voltage power supply unit 90 is provided below the scanner unit 16 and the fixing device 18 described later. The high-voltage power supply unit 95 is disposed below the process cartridge 17. A control board 201 (see FIG. 4) that controls each device of the laser printer 1 is positioned between the right side surface (front side in the figure) of the main body case 2 and the main body frame on the right hand side (not shown). Is provided. The control board 201 is arranged in a direction in which the surface direction is substantially parallel to the right side surface of the main body case 2. The low-voltage power supply unit 90 is the “power supply means” in the present invention.

  The high-voltage power supply unit 95 is a unit that generates a high-voltage bias applied to each part of the process cartridge 17 described later. A high-voltage power circuit board 202 (see FIG. 4) is disposed inside. The low-voltage power supply unit 90 is a unit for dropping, for example, a single-phase voltage of 100 V supplied from the outside of the laser printer 1 to a voltage of, for example, 24 V in order to supply each part inside the laser printer 1. is there. A low-voltage power supply circuit board 203 (see FIG. 4) constituting a circuit for this purpose is disposed at the bottom of the low-voltage power supply unit 90, and its outer periphery is covered and protected by a left and right open iron plate or the like.

  A main body frame (not shown) on the right hand side of the low-voltage power supply unit 90 is provided with a power supply fan 120 that introduces outside air to cool the low-voltage power supply unit 90 that generates a large amount of heat. The main body frame 117 (not shown) on the left hand side of the low-voltage power supply unit 90 is provided with a main fan 117 for mainly exhausting the air in the low-voltage power supply unit 90 to the outside of the laser printer 1. Yes. The left main body frame (the back side in the figure) is provided with an ozone fan 108b and a sub fan 118 in addition to the main fan 117. The positional relationship between these fans and the image forming unit 5 will be described later. .

  Next, the configuration in the vicinity of the image forming unit 5 will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the image forming unit 5 as viewed from the side. FIG. 3 is a perspective view showing the arrangement of the fans 108b, 117, 118, and 120 when the image forming unit 5 and the low-voltage power supply unit 90 are viewed from the lower rear side of the right side surface. As shown in FIGS. 2 and 3, the image forming unit 5 includes a scanner unit 16, a process cartridge 17, a fixing device 18, a duct 100, and the like so as to print on the paper 3 conveyed by the feeder unit 4. Yes.

As shown in FIG. 2, the scanner unit 16 is disposed on the lower side of the paper discharge tray 46 (see FIG. 1) in the upper part of the main body case 2, and emits laser light (not shown). A polygon mirror 19 that rotates and scans the laser beam emitted from the laser emission unit in the main scanning direction, a heat sink 130 that dissipates heat generated by the polygon mirror 19, and the laser beam scanned by the polygon mirror 19 An fθ lens 20 that keeps the scanning speed constant, a reflection mirror 21 that reflects the scanned laser light, and a relay lens that adjusts the focal position to form an image of the laser light reflected by the reflection mirror 21 on the photosensitive drum 27. 22 etc. The scanner unit 16 passes or reflects the laser light emitted from the laser light emitting unit based on the print data in the order of the polygon mirror 19, the fθ lens 20, the reflection mirror 21, and the relay lens 22 as indicated by a one-dot chain line A. Thus, exposure scanning is performed on the surface of the photosensitive drum 27 of the process cartridge 17.

  The process cartridge 17 includes a drum cartridge and a developing cartridge that can be attached to and detached from the drum cartridge. The drum cartridge includes a photosensitive drum 27, a scorotron charger 29, a transfer roller 30, a cleaning roller 51, a secondary roller 52, and the like. The developing cartridge includes a developing roller 31, a supply roller 33, a toner box 34, and the like. The process cartridge 17 is the “process means” in the present invention.

  The photosensitive drum 27 is disposed on the side of the developing roller 31 with the rotational axis of the photosensitive drum 27 parallel to the rotational axis of the developing roller 31 and in the state of contact with the developing roller 31 (counterclockwise in FIG. 2). Direction). The photosensitive drum 27 is a charge generation layer in which an organic photoconductor such as an azo pigment or a phthalocyanine pigment is dispersed in a binder resin as a charge generation material on a conductive substrate, and a hydrazone or aryl group in a resin such as polycarbonate. A drum in which a charge transport layer mixed with an amine compound or the like is laminated. When the photosensitive drum 27 is irradiated with a laser beam or the like, charges are generated in the charge generation layer by light absorption, and the charges are transported to the surface of the photosensitive drum 27 by the charge transport layer, and are supplied to the scorotron charger 29. By eliminating the charged surface potential, a potential difference can be provided between the potential of the irradiated portion and the potential of the unreceived portion. An electrostatic latent image is formed on the photosensitive drum 27 by performing exposure scanning with laser light based on the print data.

  The scorotron charger 29 as charging means is disposed above the photosensitive drum 27 at a predetermined interval so as not to contact the photosensitive drum 27. The scorotron charger 29 is a positively-charged scorotron charger that generates corona discharge from a discharge wire such as tungsten, and is configured to uniformly charge the surface of the photosensitive drum 27 to a positive polarity. Has been. The scorotron charger 29 is turned on / off by a charging bias circuit (not shown) of the high-voltage power supply unit 95. In addition, on the upper surface of the housing of the process cartridge 17 at the site where the scorotron charger 29 is provided, the air such as ozone generated during charging can be discharged to the outside of the process cartridge 17. An opening 171 that communicates is provided.

  In the state where the developing cartridge is mounted on the drum cartridge, the developing roller 31 is disposed downstream of the position of the scorotron charger 29 in the rotation direction of the photosensitive drum 27 (counterclockwise in FIG. 2). It is arranged to be rotatable in the direction of the arrow (clockwise in FIG. 2). The developing roller 31 has a metal roller shaft covered with a roller made of a conductive rubber material, and a developing bias is applied from a developing bias circuit portion (not shown) of the high-voltage power supply unit 95.

  Next, the supply roller 33 is rotatably disposed at a position on the side of the developing roller 31 and on the opposite side of the photosensitive drum 27 with the developing roller 31 interposed therebetween, and compresses the developing roller 31. The contact is made in such a state. The supply roller 33 has a metal roller shaft covered with a roller made of a conductive foam material, and frictionally charges the toner supplied to the developing roller 31.

The toner box 34 is provided at a side position of the supply roller 33, and the toner supplied to the developing roller 31 via the supply roller 33 is filled therein. In the present embodiment, a positively chargeable non-magnetic one-component toner is used as a developer, and this toner is a polymerizable monomer, for example, a styrene monomer such as styrene, acrylic acid, alkyl ( It is a polymerized toner obtained by copolymerizing acrylic monomers such as C1-C4) acrylate and alkyl (C1-C4) methacrylate by a known polymerization method such as suspension polymerization. In such a polymerized toner, a colorant such as carbon black, wax, and the like are blended, and an external additive such as silica is added in order to improve fluidity. The particle diameter is about 6 to 10 μm.

  The toner in the toner box 34 is agitated by the rotation of the agitator 36 supported by the rotation shaft 35 provided at the center of the toner box 34 in the arrow direction (counterclockwise in FIG. 2). Further, a toner remaining amount detection window 38 is provided on the side wall of the toner box 34 and is cleaned by a cleaner 39 supported by the rotary shaft 35.

  Further, a transfer roller 30 is disposed downstream of the developing roller 31 in the rotation direction of the photosensitive drum 27 and below the photosensitive drum 27, and is rotatable in the direction of the arrow (clockwise in FIG. 2). It is supported. The transfer roller 30 has a metal roller shaft covered with a roller made of an ion conductive rubber material. During transfer, a forward transfer bias is applied from a transfer bias circuit section (not shown) of the high-voltage power supply unit 95. It is configured to be. The forward transfer bias is a bias applied to the transfer roller 30 so that a potential difference is generated in a direction in which the toner electrostatically adhered on the surface of the photosensitive drum 27 is electrically attracted onto the surface of the transfer roller 30.

  Next, the cleaning roller 51 is disposed at a side position of the photosensitive drum 27. This arrangement position is the downstream position of the transfer roller 30 in the rotation direction of the photosensitive drum 27 and the upstream position of the scorotron charger 29. A secondary roller 52 is provided at a position opposite to the photosensitive drum 27 with the cleaning roller 51 in between so as to contact the cleaning roller 51, and a scraping member 53 is in contact with the secondary roller 52. Has been. The cleaning roller 51 and the secondary roller 52 are biased from a cleaning bias circuit unit (not shown) of the high-voltage power supply unit 95.

  In this laser printer 1, after toner is transferred from the photosensitive drum 27 to the paper 3 by the transfer roller 30, residual toner and paper dust remaining on the surface of the photosensitive drum 27 are electrically sucked by the cleaning roller 51. Is done. In the cleaning roller 51, only the paper dust is electrically sucked by the secondary roller 52, and the paper dust sucked by the secondary roller 52 is scraped by the scraping member 53. Then, the bias is switched, and the toner on the cleaning roller 51 returns to the photosensitive drum 27 and is collected in the developing cartridge by the developing roller 31. When the cleaning bias is switched, a reverse transfer bias is applied to the transfer roller 30 from a transfer bias circuit unit (not shown) of the high-voltage power supply unit 95. The reverse transfer bias is a bias applied to the transfer roller 30 so that a potential difference is generated in the direction in which the toner is transferred from the surface of the transfer roller 30 to the surface of the photosensitive drum 27, contrary to the forward transfer bias. is there.

  An exposure window 69 is provided above the photosensitive drum 27 of the drum cartridge so that the laser light from the scanner unit 16 is directly applied to the photosensitive drum 27. The exposure window 69 is arranged such that the photosensitive drum 27 communicates with the outside of the process cartridge 17 at a position closer to the toner box 34 than the opening 171 of the scorotron charger 29 on the upper surface of the housing of the process cartridge 17. Is open.

The fixing device 18 is disposed on the downstream side of the process cartridge 17, and includes a heating roller 41, a pressing roller 42 that presses the heating roller 41, and a pair of downstream rollers that are provided on the heating roller 41 and the pressing roller 42. A conveyance roller 43 is provided. The heating roller 41 is made of metal and includes a halogen lamp 41a (see FIG. 4) for heating inside a cylindrical roller. The toner transferred onto the paper 3 in the process cartridge 17 is transferred to the paper 3 by the paper 3 While passing between the heating roller 41 and the pressing roller 42, pressure and heat fixing is performed, and then the paper 3 is conveyed to the paper discharge path 44 by the conveying roller 43. The fixing device 18 is a “fixing unit” in the present invention.

  Further, the duct 100 that is sucked by the ozone fan 108b and the main fan 117, which will be described later, and exhausts the air to the outside of the main body case 2, corresponds to the width direction of the process cartridge 17 (the direction perpendicular to the insertion direction). This is a cylindrical exhaust passage extended in a side view and has a V-shape when viewed from the side. The interior is divided into two chambers by a partition wall 100d that divides the width direction into two, and a duct 100a for mainly discharging products such as ozone generated from the scorotron charger 29, And a duct 100b for exhausting air containing heat generated from the fixing unit 18.

  Further, when the process cartridge 17 is mounted in the main body case 2, the shutter 103 and the duct are arranged near the opening 171 provided in the vicinity of the scorotron charger 29 on the upper surface of the casing of the process cartridge 17. The exhaust chamber is covered with a lower wall surface of 100a, a partition member 104 made of an elastic member such as rubber or sponge, and a left side surface and a right side surface which are left and right side surfaces of a cartridge storage portion 57 (see FIG. 1) described later. 101 is configured. Then, the ozone generated from the scorotron charger 29 fills the exhaust chamber 101, and the scorotron charger 29 on the lower surface of the duct 100a is sucked and exhausted to the duct 100a. An opening 105 is formed in the facing portion.

  The partition member 104 is provided on the lower surface of the duct 100a so as to extend in the width direction of the process cartridge 17 (a direction orthogonal to the insertion direction) so that a tip portion in the insertion direction abuts when the process cartridge 17 is mounted. ing. Also, it plays a role as a shock absorber when the process cartridge 17 is inserted.

  The shutter 103 is a plate-like member that is long in the width direction of the process cartridge 17, and the length in the longitudinal direction is substantially the same as the width of the process cartridge 17. A support shaft 103a provided at one edge in the short direction is supported by a support portion 100c provided on the lower surface of the duct 101a. When the shutter 103 is supported, the support portion 100c is arranged so that the support shaft side of the shutter 103 is downstream of the free end side in the insertion direction of the process cartridge 17, and the free end side can move in the vertical direction. I support it to be. When the shutter 103 is closed, the free end contacts a portion between the opening portion of the scorotron charger 29 and the exposure window 69 of the process cartridge 17. The shutter 103 is opened and closed in conjunction with the opening and closing of the upper surface cover 54 by a link mechanism (not shown).

  Further, an opening 106 is also provided on the lower surface of the duct 100b, and is constituted by a wall surface at the front end in the insertion direction of the mounted process cartridge 17, the lower surface of the duct 100b, the fixing device 18, the charge removal plate 107, and the like. The air in the exhaust chamber 102 is exhausted. The neutralization plate 107 is provided between the process cartridge 17 and the fixing unit 18 on the conveyance path of the paper 3 so as to neutralize the paper 3 charged by passing through the process cartridge 17 during printing. And has a shape in which a plurality of grooves are arranged in the transport direction of the paper 3 and functions as a paper guide.

An opening 109 is provided on the wall surface of the portion of the scanner unit 16 where the heat sink 130 faces the upper surface of the duct 100. The opening 109 opens so that both the duct 100a and the duct 100b and the scanner unit 16 communicate with each other across the partition wall 100d. The heat sink 130 is exposed in a gap between the scanner unit 16 and the upper surface 61 of the duct from an exposure opening opened in the lower wall surface of the scanner unit 16. A sponge 131 is provided so as to cover the exposed heat sink 130 and to isolate the gap from other gaps. An exhaust chamber 111 is formed by a portion surrounded by the sponge 131.

  As shown in FIG. 3, a connection hole (not shown) is opened on the upper surface 61 of the duct 100 on the left side (the back side in the drawing) of the scanner unit 16. An exhaust tube 108 communicating with the outside air is provided. In the downstream portion of the exhaust passage of the exhaust cylinder 108, an ozone fan 108b for sucking air in the exhaust chamber 101 and exhausting it out of the main body case 2, and an ozone filter 108a for removing ozone contained in the air, Is provided.

  In addition, an opening 106 is formed in a wall surface 1001 that constitutes the lowermost lower surface of the duct 100. The opening 106 is opened along the wall surface from the middle position of the lowermost surface of the duct 100 to the facing surface between the duct 100 and the fixing device 18. The wall surface 1001 connects a portion 1002 facing the fixing device 18 and a portion 1003 facing the process cartridge 17 among all the wall surfaces of the duct. The wall surface opened by the opening 106 is a lower wall surface on the duct 100b side of the two ducts 100a and 100b partitioned by the partition wall 100d (see FIG. 2) inside the duct 100. The duct 100b is provided with four openings 106, and the opening position is a position closer to the right hand side of the main body case 2 in the width direction of the duct 100b.

  An exhaust main fan 117 is provided at a position closer to the left hand side of the main body case 2 in the width direction of the duct 100b. The lower half of the main fan 117 with respect to the rotation axis of the fin is opened to the low-voltage power supply unit 90, and is introduced into the low-voltage power supply unit 90 by the power supply fan 120 described above, and the low-voltage power supply circuit board 203 (FIG. 4). The air containing heat generated from (see) is exhausted. In addition, a gap is provided between the main fan 117 and the right-hand side open portion (the back side in FIG. 1) of the low-voltage power supply unit 90, and a part of the air in the exhaust chamber 102 is main through this portion. A fan 117 exhausts the outside of the laser printer 1.

  The upper half of the main fan 117 is provided with a connecting duct 112 that leads to the main fan 117 from a connection hole (not shown) opened on the opposite side of the opening 106 in the width direction of the duct 100b. The air in the duct 100b is exhausted from the main fan 117 to the outside of the main body case 2 through the connecting duct 112.

  Further, a sub fan 118 is provided at a rear position above the main fan 117 in the main body case 2. The sub-fan 118 is provided at a position facing the side surface of the fixing device 18 and exhausts air containing heat mainly generated from the fixing device 18. However, since the exhaust chamber is not particularly provided, the main body case 2 is provided. The entire interior air is exhausted.

  Next, the electrical configuration of the laser printer 1 will be described with reference to FIGS. FIG. 4 is a block diagram showing an electrical configuration of the laser printer 1. FIG. 5 is a schematic diagram showing a storage area of the ROM 211. FIG. 6 is a schematic diagram showing a storage area of the RAM 212. FIG. 7 is a schematic diagram showing a storage area of the flash RAM 217.

As shown in FIG. 4, the laser printer 1 includes a CPU 210 and an RO on a control board 201.
M 211, RAM 212, flash RAM 217, ASIC (Application Specific Integrated Circuit) 215, interface 213, and drive circuits 220 and 2
21 and 222 are provided. A ROM 211, a RAM 212, a flash RAM 217, and an ASIC 215 are connected to the CPU 210 via a bus 216, and an interface 213 and drive circuits 220 to 222 are connected to the ASIC 215. The CPU 210 executes various programs stored in the ROM 211, causes the RAM 212 to temporarily store data, and uses the values stored in the flash RAM 217 to control each device via the ASIC 215. For transmitting and receiving commands and the like. Note that the ASIC is a custom IC configured by combining various basic circuits so as to be specialized for a specific purpose of use, and has the convenience that the main part of the control circuit of the device can be realized in one chip.

  The ASIC 215 is connected to a power switch 214 for turning on / off the power of the laser printer 1, a high voltage power circuit board 202, and a low voltage power circuit board 203. Furthermore, the ozone fan 108b, the sub fan 118, the power supply fan 120, and the main fan 117 are connected to the drive circuit 220. The voltage applied to each fan from the drive circuit 220 is controlled by the CPU 210. As a result, the fan control described later is performed. The driving circuit 221 is connected to the halogen lamp 41a of the fixing unit 18, and the voltage applied to the halogen lamp 41a from the driving circuit 221 is controlled, whereby the fixing temperature of the fixing unit 18 is controlled. The drive circuit 222 is connected to other devices such as a motor and a display panel (not shown).

  The host computer 300 connected to the interface 213 of the control board 201 can transmit print data and the like to the laser printer 1.

  Next, as shown in FIG. 5, the ROM 211 stores a program executed by the CPU 210 to control the respective rotational speeds of an ozone fan 108b, a sub fan 118, a power supply fan 120, and a main fan 117, which will be described later. A fan control program storage area 211a, an initial setting storage area 211b in which various initial setting values are stored, and another program storage area 211c in which various programs for the CPU 210 to control the laser printer 1 are provided. It has been.

  Further, as shown in FIG. 6, the RAM 212 includes a counter X storage area 212a, a counter Y storage area 212b, a counter Z storage area 212c, a sub fan mode storage area 212d, a power fan mode storage area 212e, and a main fan mode storage area. 212f, a fixing temperature mode storage area 212g, and the like are provided. The counter X, Y, and Z storage areas 212a, 212b, and 212c store the count values of the counters X, Y, and Z, respectively. Further, in the sub, power supply, and main fan mode storage areas 212d, 212e, and 212f, values of “0”, “1”, and “2” are stored as the values of the SF, PF, and MF variables, respectively. Thus, when the fan control program described later is executed to control each fan, the values of these variables are referred to. When the values of these variables are “0”, the drive circuit 220 (FIG. 4) is operated so that the respective fans are driven at a medium speed rotation when “1”, and at a high speed rotation when “2”. Drive voltage is applied to each fan. The state in which each fan is driven at medium speed rotation is the “second rotation state” in the present invention, and the state in which each fan is driven at high speed rotation is the “first rotation state” in the present invention. It is.

When the sub fan 118, the power supply fan 120, and the main fan 117 are driven at high speed rotation, the voltage applied to each fan from the drive circuit 220 is 24V. When driven at medium speed rotation, the sub fan A voltage of 12V is applied to 118 and the power supply fan 120, and a voltage of 16V is applied to the main fan 117, respectively.

  Further, any one of “0”, “1”, and “2” is stored as the value of the variable Fu stored in the fixing temperature mode storage area 212g. When the value in the storage area 212g is referred to, if it is “0”, it is stopped (room temperature), if it is “1”, it is a standby temperature (about 160 degrees), and if it is “2”, it is a printing temperature (about 200 degrees). Thus, a voltage is applied from the drive circuit 221 (see FIG. 4) to the halogen lamp 41a of the fixing device 18.

  Further, as shown in FIG. 7, the flash RAM 217 is provided with a counter set value storage area 217a, other set value storage areas 217b, and the like. The flash RAM 217 retains stored contents even when the power of the laser printer 1 is turned off. When the storage of the flash RAM 217 is initialized, the values stored in the initial setting storage area 211b of the ROM 211 correspond to the storage areas corresponding to the counter setting value storage area 217a and the other setting value storage areas 217b, respectively. To be remembered. The counter set value storage area 217a stores a duration time of a ready mode, which will be described later, input in advance by a user from an input panel (not shown). The duration is selected in the range of 1 minute to 40 minutes, and 20 minutes is stored as an initial value in the initial setting storage area 211b.

  Next, each counter will be described. Each of the counters X, Y, and Z is configured so that each of the modes of the laser printer 1, that is, the print mode in which printing is performed, the ready mode for waiting for reception of print data, and the preheat of the fixing unit 18 are turned off. It is a counter for measuring the elapsed time for judging a predetermined condition in the sleep mode waiting for reception.

  The print mode counter X starts counting from “0” when print data is received for the first time after the laser printer 1 is powered on or after the counter Z is counted up in the sleep mode, and starts at “1” every second. Is added. Once the count is started, the counter X is not cleared to “0” unless the counter Z is counted up in the sleep mode. The laser printer 1 is in a print mode while printing is being performed. During this print mode, the temperature of the fixing device 18 is set to the printing temperature.

  The ready mode counter Y starts counting when the printer does not receive print data after the laser printer 1 is turned on and the fixing temperature reaches the standby temperature, or when the printing process in the laser printer 1 is completed. Every time “1” is added. Then, “0” is cleared after the end of printing when the printing process is performed during the count or after the counter Z is counted up in the sleep mode. The laser printer 1 enters the ready mode when the counter Y starts counting, and ends the ready mode when print data is received or the counter Y counts up. During this ready mode, the temperature of the fixing device 18 is set to the standby temperature.

  The sleep mode counter Z starts counting when the count value of the ready mode counter Y becomes larger than the value stored in the counter setting value storage area 217a of the flash RAM 217, and is incremented by "1" every second. . Then, when the count value becomes larger than “1200”, or when printing is performed during the count, “0” is cleared. The laser printer 1 enters the sleep mode from the time when the counter Z starts counting, and the sleep mode is continued even after the counter Z counts up, and the sleep mode is terminated upon reception of print data. During this sleep mode, no voltage is applied to the halogen lamp 41a of the fixing unit 18.

  Next, the operation at the time of printing of the laser printer 1 will be described with reference to FIGS. The uppermost sheet 3 stacked on the sheet pressing plate 7 of the sheet feeding tray 6 is pressed from the back side of the sheet pressing plate 7 toward the sheet feeding roller 8 by a spring (not shown). When printing is started based on reception of print data from the host computer 300, the paper 3 is fed by a frictional force between the rotating paper feed roller 8 and between the paper feed roller 8 and the separation pad 9. Sandwiched between. When the paper 3 separated into single sheets passes through the paper dust removing roller 10, the paper dust adhering to the surface is removed, and the paper 3 is sent to the registration roller 12 by the opposite conveying roller 11.

  On the other hand, in the scanner unit 16, the laser light generated by the laser light emitting unit (not shown) based on the laser drive signal generated by the engine controller (not shown) is emitted to the polygon mirror 19. The polygon mirror 19 scans the incident laser beam in the main scanning direction (a direction orthogonal to the conveyance direction of the paper 3) and emits it to the fθ lens 20. The fθ lens 20 converts the laser beam scanned at a constant angular velocity by the polygon mirror 19 into a constant velocity scan. The traveling direction of the laser light is changed by the reflection mirror 21, converged by the relay lens 22, and forms an image on the surface of the photosensitive drum 27.

  Further, the surface potential of the photosensitive drum 27 is charged to, for example, about 1000 V by the scorotron charger 29. Next, the photosensitive drum 27 rotating in the direction of the arrow (counterclockwise in the figure) is irradiated with laser light. The laser beam is emitted on the main scanning line of the paper 3 so that the portion to be developed is irradiated and the portion not to be irradiated is not irradiated. The portion irradiated with the laser beam (bright portion) has its surface potential. However, it drops to about 100V, for example. Then, the rotation of the photosensitive drum 27 irradiates the laser beam in the sub-scanning direction (the conveyance direction of the paper 3), and the surface of the photosensitive drum 27 is divided into a portion where the laser beam is not irradiated (dark portion) and a bright portion. An electrically invisible image, that is, an electrostatic latent image is formed thereon.

  The toner in the toner box 34 is supplied to the developing roller 31 by the rotation of the supply roller 33. At this time, the toner is positively frictionally charged between the supply roller 33 and the developing roller 31, and further adjusted so as to be a thin layer having a certain thickness and carried on the developing roller 31. For example, a positive bias of about 300 to 400 V is applied to the developing roller 31. As the developing roller 31 rotates, the positively charged toner carried on the developing roller 31 comes into contact with the photosensitive drum 27 and is formed on the surface of the photosensitive drum 27. Transfer to the electrostatic latent image. That is, since the potential of the developing roller 31 is lower than the dark portion potential (+1000 V) and higher than the bright portion potential (+100 V), the toner is selectively transferred to the light portion having a low potential. In this way, a visible image as a developer image is formed on the surface of the photosensitive drum 27, and development is performed.

  The registration roller 12 registers the sheet 3 and feeds out the sheet 3 at a timing when the leading edge of the visible image formed on the surface of the rotating photosensitive drum 27 coincides with the leading edge of the sheet 3. When the sheet 3 passes between the photosensitive drum 27 and the transfer roller 30, a negative bias lower than the bright portion potential (+100 V), for example, about −200 V is applied to the transfer roller 30. A visible image formed on the surface of the photosensitive drum 27 is transferred onto the paper 3.

Then, the sheet 3 on which the toner has been transferred is conveyed to the fixing device 18. The residual charge on the toner and the paper 3 is removed by the grounded neutralization plate 107 passing therethrough. The fixing device 18 applies heat of about 200 degrees by the heating roller 41 and pressure by the pressing roller 42 to the paper 3 on which the toner is placed, and fuses the toner onto the paper 3 to form a permanent image. The heating roller 41 and the pressing roller 42 are grounded via diodes, respectively, so that the surface potential of the pressing roller 42 is lower than the surface potential of the heating roller 41. For this reason, the positively charged toner placed on the heating roller 41 side of the sheet 3 is electrically attracted to the pressing roller 42 via the sheet 3, so that the toner is attracted to the heating roller 41 during fixing. Disturbance of the image due to is prevented.

  The sheet 3 on which the toner is pressure-heated and fixed is conveyed on the sheet discharge path 44 by the sheet discharge roller 45 and is discharged to the sheet discharge tray 46 with the printing surface facing downward. Similarly, the sheet 3 to be printed next is stacked on the sheet discharge tray 46 with the printing surface facing down on the previously discharged sheet 3. Thus, the user can obtain the sheets 3 arranged in the printing order.

  Next, control of the main fan 117, the sub fan 118, and the power supply fan 120 in the laser printer 1 will be described with reference to FIGS. 4 to 7 and the flowcharts shown in FIGS. FIG. 8 is a main routine for fan control. FIG. 9 is a flowchart of a print processing subroutine. FIG. 10 is a flowchart of a fan control process subroutine. Hereinafter, each step of the flowchart is abbreviated as “S”. The ozone fan 108b is driven at a high speed when the main fan 117 is operating, and is stopped when the main fan 117 is not operating.

  In the flowchart of the present embodiment shown below, the passage of a predetermined period set in advance using each counter X, Y, Z is measured, and fan control is performed using this as a judgment condition. As for the period, a period for driving each fan for preventing the influence of heat on the process cartridge 17 and the low-voltage power supply unit 90 of the laser printer 1 is derived in advance by an experiment or the like. When the process cartridge 17 is affected by heat, for example, the stored toner is melted by heat, so that the quality of the image formed on the paper 3 is deteriorated, or the temperature is increased by the heat on the cleaning roller 51. The cleaning performance may change due to, for example, the toner to be sucked in on the cleaning roller 51 being melted. Further, when the low-voltage power supply unit 90 is affected by heat, for example, an element disposed on the low-voltage power supply circuit board 203 is thermally destroyed, or the temperature of the low-voltage power supply circuit board 203 is determined as a standard for each of these elements. The temperature may exceed the specified temperature range. The “no effect of heat” state is a state in which the temperature of any part of the process cartridge 17 or the low-voltage power circuit board 203 is kept within a predetermined temperature range so that such a situation does not occur.

  The fan control flowcharts shown in FIGS. 8 to 10 are processed by the CPU 210 executing a program stored in the fan control program storage area 211 a of the ROM 211. This program is executed when the power of the laser printer 1 is turned on or when the laser printer 1 is reset.

  As shown in FIG. 8, when executing the fan control program, the CPU 210 first performs a process of “X, Y, Z, SF, PF, MF, Fu = 0” (S1). That is, “0” is stored in each of the counter X, Y, and Z storage areas 212a, 212b, and 212c, the sub power supply, the main fan mode storage areas 212d, 212e, and 212f, and the fixing temperature mode storage area 212g of the RAM 212. Next, the CPU 210 performs a process of “Fu = 1, fixing temperature control processing” (S2), whereby “1” is stored in the fixing temperature mode storage area 212g, and the heating roller 41 of the fixing device 18 is set to the standby temperature. Thus, a voltage is applied from the drive circuit 221 to the halogen lamp 41a.

Next, the CPU 210 executes a subroutine of “fan control processing” (S3). In this fan control process, the process of the flowchart shown in FIG. 10 is performed. As shown in FIG. 10, when the fan control processing subroutine is executed, first, the processing of “SF, PF, MF = 0” is performed (S61), and the sub-power, main fan mode storage area 2 of the RAM 212 is executed.
“0” is stored in each of 12d, 212e, and 212f. This process is set as an initial value of the operation of each fan in order to determine the operation of each fan based on each condition in the fan control process.

  Next, the CPU 210 refers to the value of the fixing temperature mode storage area 212g of the RAM 212 in order to confirm whether or not “Fu = 2” (S62). At the timing of this processing, since Fu = 1 is set in S2 of FIG. 8, the process proceeds to S63 (S62: NO), and whether or not “Fu = 1” is confirmed (S63). As in S62, the value in the fixing temperature mode storage area 212g of the RAM 212 is referred to, and in this case, Fu = 1 (S63: YES), so the processing of “PF = 1” (S65) and “MF = 1”. The processing is sequentially performed (S66), and “1” is stored in the power source of the RAM 212 and the sub fan mode storage areas 212e and 212d, respectively.

  Next, the CPU 210 executes “fan drive processing” (S74). That is, referring to the values of the sub, power supply, and main fan mode storage areas 212d, 212e, and 212f of the RAM 212, MF = 0 is set in S61, PF = 1 is set in S65, and SF = 1 is set in S66. The CPU 210 transmits a control signal to the drive circuit 220, and the drive circuit 220 drives the sub fan 118, the power supply fan 120, and the main fan 117 based on the control signal to rotate at medium speed, medium speed, and stop, respectively. In addition, a driving voltage is applied to each fan. Then, the fan control process ends, and the process returns to the fan control main routine shown in FIG.

  In the determination process of S62, when the value of the fixing temperature mode storage area 212g of the RAM 212 referred to by the CPU 210 is “2” (S62: YES), the CPU 210 refers to the value of the counter X storage area 212a of the RAM 212, Whether or not “X> 240?” Is checked (S71). When the count value of the counter X is larger than “240”, the CPU 210 proceeds to S73 (S71: YES), performs the process of “SF, PF, MF = 2” (S73), and sub-RAM of RAM 212, power supply, main fan “2” is stored in each of the mode storage areas 212d, 212e, and 212f. In S74, the fan driving process similar to that described above is performed, and the sub fan 118, the power supply fan 120, and the main fan 117 are each driven at high speed rotation (S74). When the fan control process ends, the process returns to the fan control main routine shown in FIG.

  Furthermore, when the count value of the counter X is “240” or less in S71 (S71: NO), the processing of “SF, PF, MF = 1” is performed (S72), and the RAM 212 sub, power supply, and main fan mode are stored. “1” is stored in each of the areas 212d, 212e, and 212f. In S74, the same fan driving process as described above is performed, and the sub fan 118, the power supply fan 120, and the main fan 117 are each driven at medium speed rotation (S74). When the fan control process ends, the process returns to the fan control main routine shown in FIG.

In the determination process of S63, when the value of the fixing temperature mode storage area 212g of the RAM 212 referred to by the CPU 210 is “0” (S63: NO), the CPU 210 checks whether “Z = 0?”. (S64). As described above, if the laser printer 1 does not start the sleep mode, the CPU 210 does not count the counter Z, and further, 1200 seconds (20 minutes) from the start of the counting of the counter Z in S25 and S31 of FIG. When elapses, the counter Z is reset. Accordingly, when the determination process of S64 is performed within 1200 seconds after the laser printer 1 enters the sleep mode (S64: NO), the process proceeds to S66 and S74, and the sub fan 118 is driven at medium speed rotation, and the power supply fan 120 and the main fan 117 are stopped (S74). Further, when the determination process of S64 is performed after the counter Z is reset after 1200 seconds have elapsed from the sleep mode (S64: Y
ES), the process proceeds to S74, and the sub fan 118, the power supply fan 120, and the main fan 117 are stopped (S74). When the fan control process ends, the process returns to the fan control main routine shown in FIG.

  As shown in FIG. 8, when returning from the subroutine of the fan control process in S3, the CPU 210 confirms whether “print data has been received” (S4). When the user transmits print data from the host computer 300 in order to perform printing with the laser printer 1, the print data is transmitted to the ASIC 215 via the interface 213 in the laser printer 1. The CPU 210 confirms whether or not the ASIC 215 has received the print data in S4. If the ASIC 215 has not received the print data (S4: NO), the temperature of the halogen lamp 41a to which the voltage is applied in S2 is on standby. Whether or not the temperature has been reached, that is, whether or not the fixing device is equal to or higher than the standby temperature is checked using a temperature sensor (not shown) (S6). If the fixing device has not reached the standby temperature (S6: NO), the process returns to S4 and the same determination process is repeated.

  If the ASIC 215 has received the print data when the CPU 210 confirms the reception of the print data in S4 (S4: YES), the “print processing” subroutine is executed (S5). In this printing process, the process of the flowchart shown in FIG. 9 is performed. During this printing process, the laser printer 1 is in a print mode.

  As shown in FIG. 9, when the print processing subroutine is executed, the CPU 210 refers to the value in the counter X storage area 212a of the RAM 212 to check whether "X = 0?" (S41). If the count value of the counter X is “0” (S41: YES), the CPU 210 “starts counting of the counter X” (S42), and if the counter X is counting (S41: NO), the counter X The process proceeds to S43 while continuing the count.

  Then, the CPU 210 performs a process of “Fu = 2, fixing temperature control process” (S43). That is, “2” is stored in the fixing temperature mode storage area 212g, and a voltage is applied from the drive circuit 221 to the halogen lamp 41a so that the heating roller 41 of the fixing device 18 reaches the printing temperature.

  Next, the CPU 210 executes a “fan control process” subroutine (S44), and performs the process of the flowchart shown in FIG. When this printing process is performed for the first time after power-on or after the count value of the counter X is reset, the process proceeds to S42 in the determination process of S41 in FIG. This subroutine will be performed. Accordingly, as shown in FIG. 10, in the determination process of S71 after the processes of S61 and S62 are performed, the counter X is “240” or less, so the process proceeds to S72, and then the fan drive process of S74 is performed. The sub fan 118, the power supply fan 120, and the main fan 117 are each driven at medium speed rotation.

  Then, returning to the printing process of FIG. 9, whether or not “the fixing device is equal to or higher than the printing temperature” is confirmed using a temperature sensor (not shown) (S45). The CPU 210 waits for processing until the temperature of the fixing device 18 reaches the printing temperature (S45: NO). When the temperature reaches the printing temperature (S45: YES), “printing is started” (S51).

The counter X continues to count even during the standby until the fixing device reaches the printing temperature in S45. Then, the CPU 210 checks whether or not “X> 240?” (S52). If the count value of the counter X is “240” or less, the CPU 210 proceeds to S53 (S52: NO), and determines whether “printing is finished” or not. Is confirmed (S53). If printing is in progress (S53: NO), the process returns to S52 to check the count value of the counter X. In this way, during printing in which the count value of the counter X is “240” or less, the processes of S52 and S53 are performed alternately, and the fan control is not performed.

  When the count value of the counter X becomes larger than “240” (S52: YES), the CPU 210 executes a “fan control process” subroutine (S54) and performs the process of the flowchart shown in FIG. . In the fan control process shown in FIG. 10, since printing is being performed at this time, the process is performed in the order of S61, S62, and S71, and the process proceeds to S73 in the determination process of S71, so that SF, PF, and MF = 2 are set. The fan drive process of S74 is performed. Therefore, after 240 seconds (4 minutes) have elapsed from when the counter X starts counting, that is, after the power is turned on, or after the count value of the counter X is reset for the first time, the sub fan 118, the power fan 120, Each of the main fans 117 is driven at a high speed.

  When the execution of the subroutine of the fan control process in S54 is completed, the CPU 210 confirms whether or not “printing is finished” as shown in FIG. 9 (S55), and if printing is in progress, waits until printing is finished. (S55: NO). When printing is completed (S55: YES), the CPU 210 performs a process of “Y, Z = 0, Fu = 1, fixing temperature control process” (S56). That is, “0” is stored in the counter Y and Z storage areas 212b and 212c of the RAM 212, “1” is stored in the fixing temperature mode storage area 212g, and the heating circuit 41 of the fixing device 18 is set to the standby temperature. To the halogen lamp 41a. Thereafter, the process returns to the fan control main routine shown in FIG. Note that the end of printing in S53 and S55 indicates that the sheet 3 is discharged to the discharge tray 46 and the driving of the photosensitive drum 27 and the discharge roller 45 is stopped.

  When the fixing device 18 reaches the standby temperature in S6 of FIG. 8 (S6: YES), or when the print processing subroutine of S5 is completed, the CPU 210 “starts counting of the counter Y” (S11). . In other words, the ready mode is started in which the fixing device 18 waits for reception of print data while being controlled at the standby temperature. Then, the CPU 210 executes a “fan control process” subroutine to set the rotation speed of each fan in the ready mode (S12), and performs the process of the flowchart shown in FIG. At this time, since printing has not been performed and Fu = 1 is set, the fan control processing subroutine of FIG. 10 proceeds in the order of S61, S62, S63, S64, S65, S66, and SF, PF = 1. , MF = 0. Then, the process of S74 is performed, each of the sub fan 118 and the power supply fan 120 is driven at medium speed rotation, and the main fan 117 is stopped.

  Next, when returning to the fan control main routine shown in FIG. 8, the CPU 210 confirms whether or not “print data has been received” (S13). Similar to the processing in S4 described above, the CPU 210 confirms whether or not the ASIC 215 has received the print data. If the ASIC 215 has not received the print data (S13: NO), “Y> set value? Is confirmed (S14). The CPU 210 compares the setting value stored in the counter setting value storage area 217a of the flash RAM 217 with the value in the counter Y storage area 212b of the RAM 212. If the count value of the counter Y is equal to or less than the setting value (S14: NO) ), The process returns to S13 and the determination process of S13 and S14 is repeated.

Here, in the process of S13, when the CPU 210 can confirm that the ASIC 215 has received the print data (S13: YES), the CPU 210 executes a print process subroutine of S5. Then, the process of the flowchart shown in FIG. 9 is performed as described above, the laser printer 1 enters the print mode, and printing is started. Then, after the count value of the counter Y is reset in the process of S56 before the end of this subroutine, the process returns to the fan control main routine shown in FIG. 8, and the processes after S11 are performed. That is, the laser printer 1 enters the ready mode after the printing is completed.

  When it is determined in S14 that the count value of the counter Y is larger than the set value (S14: YES), the CPU 210 “starts counting of the counter Z” (S21). Further, the CPU 210 performs “Fu = 0, fixing temperature control processing” (S22), “0” is stored in the fixing temperature mode storage area 212g, and the application of voltage to the halogen lamp 41a of the fixing device 18 is stopped. The That is, a sleep mode is started in which the reception of print data is waited with the preheating of the fixing device 18 turned off. Then, the CPU 210 executes a “fan control process” subroutine to set the rotation speed of each fan in the sleep mode (S23), and performs the process of the flowchart shown in FIG. At this time, Fu = 0 is set in the process of S22, and the count of the counter Z is started. Accordingly, the fan control processing subroutine of FIG. 10 proceeds in the order of S61, S62, S63, S64, and S66, and SF = 1, PF, and MF = 0 are set. Then, the process of S74 is performed, the sub fan 118 is driven at medium speed rotation, and the power supply fan 120 and the main fan 117 are stopped.

  Next, when returning to the main routine of the fan control shown in FIG. 8, the CPU 210 confirms whether “print data has been received” (S24). Similar to the processing in S13 described above, the CPU 210 confirms whether or not the ASIC 215 has received the print data. If the ASIC 215 has not received the print data (S24: NO), “Z> 1200?” Confirmation is made (S25). When the value of the counter Y storage area 212b of the RAM 212 is equal to or less than “1200” (S25: NO), the CPU 210 returns to S24 and repeats the determination processes of S24 and S25.

  Here, in the process of S24, when the CPU 210 can confirm that the ASIC 215 has received the print data (S24: YES), the CPU 210 executes a subroutine of the print process of S5. Then, the process of the flowchart shown in FIG. 9 is performed as described above, the laser printer 1 enters the print mode, and printing is started. When printing is finished, the process returns to the fan control main routine shown in FIG. That is, the laser printer 1 is in a ready mode after printing is completed.

  When it is determined in S25 that the count value of the counter Z is larger than “1200” (S25: YES), that is, when 1200 seconds (20 minutes) have elapsed since the laser printer 1 entered the sleep mode, the CPU 210 , “X, Y, Z = 0” is performed (S31). “0” is stored in each of the counter X, Y, and Z storage areas 212a, 212b, and 212c of the RAM 212. Then, the CPU 210 executes a “fan control process” subroutine (S32) and performs the process of the flowchart shown in FIG. At this time, since Fu = 0 is set in the process of S22, the subroutine of the fan control process of FIG. 10 proceeds in the order of S61, S62, S64, and SF, PF, MF = 0 is set. And the process of S74 is performed and the sub fan 118, the power supply fan 120, and the main fan 117 are each stopped.

Next, when returning to the fan control main routine shown in FIG. 8, the CPU 210 confirms whether or not “print data has been received” (S33). The CPU 210 confirms whether or not the ASIC 215 has received the print data. If the ASIC 215 has not received the print data (S33: NO), the CPU 210 continues the print data reception confirmation process. If the CPU 210 can confirm that the ASIC 215 has received the print data (S33: YES), the print processing subroutine of S5 is executed, and the processing of the flowchart shown in FIG. The printer 1 enters the print mode and printing starts. When the printing is completed, the process returns to the fan control main routine shown in FIG.

  Next, an example of the drive control timing of each fan will be described with reference to FIGS. FIG. 11 is an example of a timing chart of drive control of each fan.

  When the power of the laser printer 1 is turned on at the timing T0 shown in FIG. 11, first, in S2 of FIG. 8, a voltage for setting the fixing unit 18 to the standby temperature is applied to the halogen lamp 41a. Next, the process of S3 is performed, and the sub fan 118 and the power supply fan 120 are each driven at medium speed rotation. Then, the processes of S4 and S5 are repeated during the timings T0 to T1 until the temperature of the fixing device 18 reaches the standby temperature.

  Next, the processing of S11 and S12 is performed at the timing T1, and the count of the counter Y is started. The laser printer 1 enters the ready mode, and the processing of S13 and S14 is repeated after the timing T1. When the CPU 210 confirms the reception of the print data of the ASIC 215 at the timing T2, the printing process of S5 is performed, the laser printer 1 enters the print mode, and printing is started. Since this printing process is the first printing process after the power is turned on, the counter X starts counting from this T2 timing. Further, the voltage applied to the halogen lamp 41a is controlled so that the temperature of the fixing device 18 becomes the printing temperature, and the sub fan 118, the power supply fan 120, and the main fan 117 are each driven at medium speed rotation. The T5 timing is 240 seconds after the T2 timing at which the counter X starts counting.

  When the printing process of S5 ends at the timing T3, the counter Y starts counting, and the laser printer 1 enters the ready mode. At this T3 timing, 240 seconds have not elapsed since the T2 timing at which the counter X starts counting, and the sub fan 118 and the power supply fan 120 are each driven at medium speed rotation by the fan control processing of S12, and the main fan 117 is Stopped. Further, the voltage applied to the halogen lamp 41a is controlled so that the fixing temperature of the fixing device 18 becomes the standby temperature. Further, after the timing T3, the processes of S13 and S14 are repeated. When the CPU 210 confirms reception of the print data of the ASIC 215 at the timing T4, the print process of S5 is performed, the laser printer 1 enters the print mode, and printing is started.

When the count value of the counter X becomes larger than “240” at the timing T5 while the printing process shown in FIG. 9 is being performed, the process proceeds from the determination process of S52 to the process of S54, and the fan control process is performed. At this timing T5, since the print mode is being performed and the count value of the counter X is “240” seconds or more, the sub fan 118, the power supply fan 120, and the main fan 117 are each driven at high speed rotation. At time T6, the printing process of the laser printer 1 ends.

  At the timing T6, the counter Y reset at the end of the printing process in S5 starts again from S11, and the laser printer 1 enters the ready mode. Then, the sub fan 118 and the power supply fan 120 are driven at medium speed rotation by the fan control processing of S12, and the main fan 117 is stopped. If the CPU 210 does not detect reception of print data of the ASIC 215 during the ready mode, the count value of the counter Y reaches the set value stored in the counter set value storage area 217a of the flash RAM 217 at the timing T7, and the process of S21 Accordingly, the counting of the counter Z is started, and the laser printer 1 enters the sleep mode. In S22, the application of voltage to the halogen lamp 41a of the fixing unit 18 is stopped, and further, fan control processing is performed in S23. The sub fan 118 is driven at medium speed rotation, and the power fan 120 and main fan 117 are driven. Are stopped respectively.

  During the sleep mode after the T7 timing, the processes of S24 and S25 are repeated. When the CPU 210 confirms reception of the print data of the ASIC 215 at the timing T8 in the sleep mode, the print process of S5 is performed as described above, the laser printer 1 enters the print mode, and printing is started. The mode of each fan at this time is the same as in the case of T5 timing, and the sub fan 118, the power supply fan 120, and the main fan 117 are each driven at high speed rotation.

  When the printing process of the laser printer 1 is completed at the timing T9, the laser printer 1 enters the ready mode similarly to the timing T6. That is, through the processing of S11 and S12, each of the sub fan 118 and the power supply fan 120 is driven at medium speed rotation, the main fan 117 is stopped, and the halogen lamp so that the fixing temperature of the fixing device 18 becomes the standby temperature. A voltage is applied to 41a. The counter Y, which has started counting at the timing T6, counts up at the timing T7 and starts counting by the counter Z, but the laser printer 1 enters the print mode at the timing T8 before the counter Z counts up. Therefore, the count is continued until the print mode ends at the timing T9.

  Further, when the count value of the counter Y reaches the set value stored in the counter set value storage area 217a at the timing T10, the count of the counter Z is started according to the process of S21, and the laser printer 1 enters the sleep mode. In step S22, the voltage application to the halogen lamp 41a of the fixing unit 18 is stopped. In step S23, fan control processing is performed. The sub fan 118 is driven at medium speed rotation, and the power fan 120 and main fan 117 are driven. Are stopped respectively.

  Next, when the counter Z counts up at the timing of T11, each counter X, Y, Z is reset by the process of S31. Then, the fan control process of S32 is performed, and the sub fan 118, the power supply fan 120, and the main fan 117 are stopped. This sleep mode is continued by repeating the determination process of S33 until the CPU 210 confirms reception of the print data of the ASIC 215 at the T12 timing. From this timing T12, the laser printer 1 enters the print mode. Since the count value of the counter X is reset to “0” at the timing T11, the counting of the counter X is started again at the timing T12, and each of the sub fan 118, the power supply fan 120, and the main fan 117 is started. However, it is driven at medium speed rotation. Then, after the printing process is finished at the timing T13, the process returns to the process of S11, and the fans are similarly controlled thereafter.

  Next, a laser printer 1 according to the second embodiment will be described with reference to FIGS. FIG. 12 is a schematic diagram illustrating a storage area of the RAM 212 according to the second embodiment. Similarly to the laser printer 1 of the first embodiment, the laser printer 1 of the second embodiment receives print data in a print mode in which printing is performed and the fixing device 18 is controlled to a standby temperature. There is a ready mode for waiting, and a sleep mode for waiting for reception of print data in a state where the preheating of the fixing device 18 is turned off. In the laser printer 1 of this embodiment, intermittent fan control is executed during the ready mode.

  As shown in FIG. 12, in the RAM 212 of the laser printer 1 of the second embodiment, in addition to the configuration of the storage area of the RAM 212 of the first embodiment, a counter A storage area 212h and an intermittent flag B storage area 212i. Is provided. The counter A storage area 212h stores the count value of the counter A, and the intermittent flag B storage area 212i is a flag for determining a predetermined condition in intermittent fan control described later, that is, "0" or "1". The value of is stored.

  In the sub, power supply, and main fan mode storage areas 212d, 212e, and 212f, values of “0”, “1”, and “2” are stored as values of variables of SF, PF, and MF, respectively. Therefore, the values of these variables are referred to when an intermittent fan control program described later is executed to control each fan. When the values of these variables are “0”, the drive circuit 220 (FIG. 4) is operated so that the respective fans are driven at a medium speed rotation when “1”, and at a high speed rotation when “2”. Drive voltage is applied to each fan.

  When the sub fan 118, the power supply fan 120, and the main fan 117 are driven at high speed rotation, the voltage applied to each fan from the drive circuit 220 is 24V. When driven at medium speed rotation, the sub fan A voltage of 12 V is applied to 118 and the power supply fan 120, and a voltage of 16 V is applied to the main fan 117. In the laser printer 1 of the present embodiment, the driving speed of each fan during the intermittent fan control is performed. As a result, high speed rotation is not selected.

  The counter A is a counter for measuring an elapsed time for determining a predetermined condition during the ready mode of the laser printer 1. The counter A starts counting when the laser printer 1 enters the ready mode, and is incremented by “1” every second. Then, “0” is cleared after the end of printing when the printing process is performed during the count or after the counter A is counted up, and the count starts again from “0”. Then, the intermittent fan control ends when the counter Y counts up.

  The configuration of other parts of the laser printer 1 of the second embodiment is the same as that of the first embodiment.

  Next, control of the main fan 117, the sub fan 118, and the power supply fan 120 in the laser printer 1 of the second embodiment will be described with reference to the flowcharts shown in FIGS. FIG. 13 is a main routine for intermittent fan control according to the second embodiment. FIG. 14 is a flowchart of a subroutine of intermittent fan control processing. The flowchart of the intermittent fan control shown in FIGS. 13 and 14 is processed by the CPU 210 executing the program stored in the fan control program storage area 211a of the ROM 211 as in the above embodiment. This program is executed when the power of the laser printer 1 is turned on.

  As shown in FIG. 13, when the CPU 210 executes the intermittent fan control program, it first performs the processing of “Y, SF, PF, MF = 0” (S79), the counter Y storage area 212b of the RAM 212, the sub, power supply , “0” is stored in each of the main fan mode storage areas 212d, 212e, and 212f. Then, the CPU 210 confirms whether or not “the fixing device is equal to or higher than the standby temperature” (S80). That is, the CPU 210 uses a temperature sensor (not shown) to check whether the temperature of the fixing device 18 to which the voltage is applied from the drive circuit 221 to the halogen lamp 41a has reached the standby temperature. The CPU 210 waits for processing until the temperature of the fixing device 18 reaches the standby temperature (S80: NO). When the temperature reaches the standby temperature (S80: YES), the CPU 210 proceeds to the processing of S81. In the present embodiment, the temperature control of the fixing device 18 is performed by another program.

  Then, the CPU 210 “starts counting of the counter Y” (S81), and the ready mode in which the laser printer 1 waits for reception of print data is started. Then, the CPU 210 performs a process of “A, B = 0” (S82), and stores “0” in each of the counter A storage area 212h and the intermittent flag B storage area 212i of the RAM 212.

  Next, the CPU 210 determines whether “A = 0?” (S83). If the value of the counter A storage area 212h is referred to and the count value of the counter A is “0” (S83: YES), the CPU 210 “starts counting of the counter A” (S84) and rotates each fan. In order to set the speed, a subroutine of “intermittent fan control process” is executed (S85), and the process of the flowchart shown in FIG. 14 is performed.

  As shown in FIG. 14, when the intermittent fan control processing subroutine is executed, first, the processing of “SF = 1, PF, MF = 0” is performed (S111), and the sub fan mode storage area 212d of the RAM 212 is stored. “1” is stored, and “0” is stored in each of the power source and main fan mode storage areas 212e and 212f. This process is set as an initial value of the operation of each fan in order to determine the operation of each fan based on each condition in the fan control process.

  Next, the CPU 210 refers to the value of the counter A storage area 212h of the RAM 212 in order to check whether “A> 60?” (S112). At the timing of this processing, immediately after the count of the counter A is started in S84 and the count value of the counter A is “60” or less (S112: NO), the CPU 210 determines whether “Y> 1800?” Is confirmed (S114). At the timing of this processing, immediately after the count of the counter Y is started in the processing of S81 in FIG. 13 and the count value of the counter Y is “1800” or less (S114: NO), the CPU 210 performs “fan drive processing”. Is performed (S116). After SF = 1, PF, and MF = 0 are set in the process of S111, the process proceeds to S112 and S114, and the fan drive process of S116 is performed with the set value of the fan mode as it is. Drive voltage is applied from the drive circuit 220 so that the power supply fan 120 and the main fan 117 are stopped by being driven by rotation. Thereafter, the process returns to the main routine of intermittent fan control shown in FIG.

  When the count value of the counter A is larger than “60” in S112 (S112: YES), that is, when 60 seconds have elapsed after the count start of the counter A, the process of “PF = 1” is performed (S113). “1” is stored in the power supply fan mode storage area 212 e of the RAM 212. Then, since fan driving processing based on SF, PF = 1, and MF = 0 is performed (S116), each of the sub fan 118 and the power supply fan 120 is driven at medium speed rotation, and the main fan 117 is stopped. Thereafter, the process returns to the main routine of intermittent fan control shown in FIG.

  Even if the count value of the counter A is smaller than “60”, if the count value of the counter Y is larger than “1800” in S114 (S112: NO, S114: YES), that is, 1800 seconds ( When 30 minutes have elapsed, “MF = 1” is processed (S115), and “1” is stored in the main fan mode storage area 212f of the RAM 212. Then, since fan drive processing based on SF, MF = 1, and PF = 0 is performed (S116), each of the sub fan 118 and the main fan 117 is driven at medium speed rotation, and the power supply fan 120 is stopped. Thereafter, the process returns to the main routine of intermittent fan control shown in FIG.

  As shown in FIG. 13, when returning from the subroutine of the intermittent fan control process of S85, the CPU 210 checks whether “print data has been received” (S103). As in the first embodiment, the CPU 210 confirms whether the ASIC 215 has received the print data. If the ASIC 215 has received the print data (S103: YES), the CPU 210 performs the “print” process. It performs (S105). In this printing process, each fan is controlled to the operation state at the time of printing, and all the fans are driven at medium speed rotation. Then, after the count value of the counter Y is reset at the end of the printing process, the process returns to S81.

  In S103, the CPU 210 confirms whether the ASIC 215 has received the print data. If the ASIC 215 has not received the print data (S103: NO), the CPU 210 confirms whether “Y> set value?” S104). The CPU 210 compares the setting value stored in the counter setting value storage area 217a of the flash RAM 217 with the value in the counter Y storage area 212b of the RAM 212. If the count value of the counter Y is equal to or less than the setting value (S104: NO) ), Returning to S83, if the count value of the counter Y is larger than the set value (S104: YES), the intermittent fan control is terminated. In this case, the laser printer 1 enters the sleep mode because the time specified as the set value has elapsed in the ready mode. The control of each fan during the sleep mode is the same as that of the first embodiment, that is, the sub fan 118 is within 1200 seconds (20 minutes) after the start of the sleep mode without receiving print data. Only the motor is driven at a medium speed, and after 1200 seconds, all the fans are stopped.

  If it is determined in S104 that the count value of the counter Y is equal to or less than the set value (S104: NO), the process returns to S83, and the count value of the counter A is referred to. In this case, since the process of S84 is performed, the count of the counter A is started (S83: NO), and the process proceeds to S91. Then, the CPU 210 checks whether “A> 60?” (S91). The CPU 210 refers to the count value of the counter A in the same manner as described above, and if it is within 60 seconds after the counter A starts counting, the process proceeds to S103 (S91: NO), and conditions such as reception of print data and count-up of the counter Y are performed. Unless S is satisfied, the processes of S103, S104, S83, and S91 are repeated.

  When the count value of the counter A is larger than “60” (S91: YES), the CPU 210 checks whether “B = 0?” (S92), and the intermittent flag B storage area 212i of the RAM 212 is checked. Refers to the value. When the count value of the counter A becomes larger than “60” for the first time, the intermittent flag B is “0” in the process of S82 (S92: YES), and the “intermittent fan control process” subroutine is executed ( S93), the process of the flowchart shown in FIG. 14 is performed. At this time, since the counter A is larger than “60” in S112 (S112: YES), SF, PF = 1, MF = 0, that is, each of the sub fan 118 and the power supply fan 120 is driven at medium speed rotation, and the main fan 117 is stopped.

  Next, when returning to the intermittent fan control main routine shown in FIG. 13, the CPU 210 processes “B = 1” (S94), and stores “1” in the intermittent flag B storage area 212i of the RAM 212. Then, the CPU 210 checks whether “A> 900?” (S101). If the count value of the counter A is “900” or less (S101: NO), the CPU 210 proceeds to S103 and S104, and returns to the process of S83 unless conditions such as reception of print data and count-up of the counter Y are satisfied.

  At this time, in the determination process of S92, since the value of the intermittent flag B is set to “1” in S94 when the previous process was performed (S92: NO), the process proceeds to S101. As described above, the intermittent fan control processing subroutine is executed only once when the condition for treatment is satisfied.

  Then, when the count value of the counter A becomes larger than “900” (S101: YES), the CPU 210 performs the process of “A, B = 0” (S102), the counter A storage area 212h and the intermittent flag B of the RAM 212. “0” is stored in each of the storage areas 212i. Further, the CPU 210 returns to the process of S83 unless conditions such as reception of print data and count-up of the counter Y are satisfied.

  Next, an example of the drive control timing of each fan in the laser printer 1 according to the second embodiment will be described with reference to FIGS. FIG. 15 is an example of a timing chart of drive control of each fan.

  As shown in FIG. 15, the laser printer 1 is turned on, and at T0 timing when the temperature of the fixing unit 18 reaches the standby temperature, S81 of FIG. 13 is processed, and the counter Y starts counting. Since the counter A is reset in S82, the process proceeds to S83 and S84, and the counter A starts counting. Further, the intermittent fan control process of S85 is performed, and at this T0 timing, the count value of the counter A is “60” or less and the count value of the counter Y is “1800” or less, so only the sub fan 118 is in the middle. Driven at high speed.

  Thereafter, the processes of S83, S91, S103, and S104 are repeated. When 60 seconds elapse from the T0 timing and the count value of the counter A becomes larger than “60” at the T1 timing, the process proceeds from the determination process of S91 to S92. At the timing T1, the value of the intermittent flag B is “0”, and the intermittent fan control process of S93 is executed. At this time, since the count value of the counter A is larger than “60”, the sub fan 118 and the power supply fan 120 are each driven at medium speed rotation. Since the value of the intermittent flag B is “1”, the processing of S83, S91, S92, S101, S103, and S104 is repeated after the T1 timing, and 900 seconds (15 minutes) from the T0 timing at the T2 timing. When the count value of the counter A becomes greater than “900” after a lapse, the process proceeds from the determination process of S101 to S102.

  At the timing T2, since the counter A and the intermittent flag B are reset in S102, the process proceeds from S83 to S84 and S85. In the intermittent fan control process of S85, the count value of the counter A is “60” or less and the count value of the counter Y is “1800” or less, similarly to the T1 timing. Driven. Since the process under the same determination conditions as the T1 timing is performed at the T3 timing, the sub fan 118 and the power supply fan 120 are each driven at medium speed rotation.

  When 900 seconds (15 minutes) have elapsed from the T2 timing and the count value of the counter A becomes greater than “900” at the T4 timing, S101 and S102 are processed, so that the counter A and the intermittent flag are the same as the T2 timing. B is reset, and the process proceeds to S85 through S83 and S84. In the intermittent fan control process of S85, the count value of the counter A is “60” or less as in the T1 timing, but 1800 seconds (30 minutes) have elapsed from the T0 timing, and the count value of the counter Y is “ Therefore, the sub fan 118 and the main fan 117 are driven at medium speed rotation.

  Thereafter, the processes of S83, S91, S103, and S104 are repeated, and at T5 timing, when 60 seconds have elapsed from the T4 timing and the count value of the counter A becomes larger than “60”, the processing of S93 is performed through the processing of S91 and S92. A subroutine for intermittent fan control processing is executed. In this intermittent fan control processing subroutine, the processing of S111, S112, S113, and S116 of FIG. 14 is performed, and the sub fan 118 and the power supply fan 120 are each driven at medium speed rotation. Thereafter, the processes of S83, S91, S92, S101, S103, and S104 are repeated from the T4 timing to the T6 timing at which 900 seconds (15 minutes) have elapsed.

  Thereafter, the intermittent fan control process similar to the timing of T4 to T6 is repeated in the respective periods of T6 to T8 timing, T8 to T10 timing, and T10 to T12 timing, whereby the power supply fan 120 and the main fan 117 alternate. Further, the power supply fan 120 is driven at a medium speed for 60 seconds and the main fan 117 is driven for 840 seconds (14 minutes).

  Then, at a timing T12, when a predetermined period elapses from the timing T0 and the count value of the counter Y reaches the set value stored in the counter set value storage area 217a, the ready mode of the laser printer 1 is terminated, and this intermittent Fan control ends. During the period from T12 to T13, the laser printer 1 is in the sleep mode, and only the sub fan 118 is driven at medium speed rotation during this period.

  As described above, in the laser printer 1 according to the first embodiment, the fixing device is used after a predetermined period, for example, 4 minutes have elapsed since the start of the first printing process after power-on or reset. 18 and the low-voltage power supply unit 90, etc., the sub-fan 118, the power-supply fan 120, and the main fan 117 are driven at a medium speed to cause wind noise. Noise can be reduced. Even when the printing process is not performed, the rotation speed of each fan can be controlled to reduce noise. Further, in the laser printer 1 according to the second embodiment, the power fan 120 and the main fan 117 are alternately driven during the ready mode for waiting for reception of print data, so that noise caused by the wind noise of the fan is generated. Can be reduced.

  Needless to say, the present invention can be variously modified. For example, intermittent fan control of the laser printer 1 according to the second embodiment may be performed during the ready mode of the laser printer 1 according to the first embodiment. In this case, the processes from S81 to S104 in FIG. 13 may be executed instead of the processes from S11 to S14 in FIG. At this time, in the “printing” process of S105, the intermittent fan control process can be realized in the laser printer 1 of the first embodiment by executing the printing process subroutine shown in FIG.

  Further, during the sleep mode of the laser printer 1 of the first embodiment, the sub fan 118 and the power supply fan 120 are driven at medium speed rotation within 4 minutes after the counter X starts counting, and the main fan 117 is driven. It may be stopped. As described above, the ready mode can be selected by the user in the range of 1 to 40 minutes, and may enter the sleep mode within 4 minutes after the initial printing by the laser printer 1. 18 and the low voltage power supply unit 90 can reduce the influence of heat. In this case, if “NO” in the determination process of S63 of FIG. 10, a determination process of “Is X> 240?” Is performed, and if “YES”, the process of S64 is performed, and “NO” is determined. If there is, the process of S65 may be performed.

  Further, not only the counter Y but also the count values counted up by the counters X, Z, and A may be set arbitrarily. The timing at which the counter X starts to count is the start of a print processing subroutine (see FIG. 9) executed by the CPU 210 confirming that the ASIC 215 has received the print data. For example, the ASIC 215 It is started when a predetermined condition is satisfied, such as when the received print data is expanded as printable data, when the temperature of the fixing device 18 reaches the print temperature, or when paper feeding is started. Also good.

  The timing at which the counter Y starts counting is when the fixing temperature reaches the standby temperature after the laser printer 1 is turned on or when the printing process in the laser printer 1 is completed. It may be started when a predetermined condition is satisfied, such as when the main motor (not shown) is stopped, or when the temperature of the fixing device 18 is set to the standby temperature and a predetermined period elapses.

Further, the rotational speeds of the high-speed rotation and the medium-speed rotation of each fan may be arbitrarily set. Further, in the fan control process subroutine shown in FIG. 10, in the fan drive process of S74, the drive start timing of each fan may be started at an arbitrary timing, not at the same time. Furthermore, the rotational speed of each fan was two speeds, high speed and medium speed.
There may be three or more.

FIG. 1 is a central sectional view of a laser printer 1 according to the first embodiment. FIG. 2 is a cross-sectional view of the image forming unit 5 as viewed from the side. FIG. 3 is a perspective view showing the arrangement of the fans 108b, 117, 118, and 120 when the image forming unit 5 and the low-voltage power supply unit 90 are viewed from the lower rear side of the right side surface. FIG. 4 is a block diagram showing an electrical configuration of the laser printer 1. FIG. 5 is a schematic diagram showing a storage area of the ROM 211. FIG. 6 is a schematic diagram showing a storage area of the RAM 212. FIG. 7 is a schematic diagram showing a storage area of the flash RAM 217. FIG. 8 is a main routine for fan control. FIG. 9 is a flowchart of a print processing subroutine. FIG. 10 is a flowchart of a fan control process subroutine. FIG. 11 is an example of a timing chart of drive control of each fan. FIG. 12 is a schematic diagram illustrating a storage area of the RAM 212 according to the second embodiment. FIG. 13 is a main routine for intermittent fan control according to the second embodiment. FIG. 14 is a flowchart of a subroutine of intermittent fan control processing. FIG. 15 is an example of a timing chart of drive control of each fan.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Main body case 3 Paper 17 Process cartridge 18 Fixing device 90 Low voltage | pressure power supply unit 117 Main fan 118 Sub fan 120 Power supply fan

Claims (3)

Process means for transferring a developer image that has become noticeable by the developer to a recording medium;
Fixing means for fixing the developer image transferred to the recording medium by the process means to the recording medium;
Power supply means for supplying power to the process means and the fixing means;
A main fan for cooling the power supply means, the fixing means, and the process means;
A power supply fan for cooling the power supply means;
A sub-fan for cooling the fixing unit;
A plurality of fans for cooling the main body case comprising the main fan, the power supply fan, and the sub fan, and fan control means for independently controlling the rotation speeds of the plurality of fans. An image forming apparatus,
The fan control means operates the sub fan until a predetermined period elapses after printing processing ends or until print data is received, and one of the power supply fan and the main fan is operated. In this case, the other fan is stopped, and the respective fans are controlled so that their operation states are alternately switched every predetermined period .
Process means for transferring a developer image that has become noticeable by the developer to a recording medium;
Fixing means for fixing the developer image transferred to the recording medium by the process means to the recording medium;
Power supply means for supplying power to the process means and the fixing means;
A main fan for cooling the power supply means, the fixing means, and the process means;
A power supply fan for cooling the power supply means;
A sub-fan for cooling the fixing unit;
A plurality of fans for cooling the main body case comprising the main fan, the power supply fan, and the sub fan, and fan control means for independently controlling the rotation speeds of the plurality of fans. An image forming apparatus,
The fan control unit operates the sub fan when the control is started so that the temperature of the fixing unit is lower than the temperature when printing is performed, and the power supply fan and the main fan are operated. An image forming apparatus that controls each of the fans so that when one of them is operated, the other is stopped and the operation state is alternately switched every predetermined period .
Process means for transferring a developer image that has become noticeable by the developer to a recording medium;
An image forming apparatus comprising: fixing means for fixing the developer image transferred to the recording medium by the process means to the recording medium;
A power supply fan for cooling the power supply means provided to supply power to the process means and the fixing means;
A sub-fan for cooling the fixing unit;
A main fan for cooling the power supply means, the fixing means, and the process means;
Fan control means for independently controlling the rotational speed of each fan ;
Fixing temperature control means for controlling the temperature of the fixing means ,
The fan control unit operates the sub fan at a first timing when the control is started so that the temperature of the fixing unit becomes a predetermined temperature lower than a temperature when printing is performed, and the power source After the fan is stopped for a predetermined period, the control for repeating the operation for a predetermined period is repeatedly performed, and the main fan is stopped when the power supply fan is operated from the second timing after the predetermined period from the first timing. And controlling the operation when the power supply fan is stopped, stopping the driving of the fixing unit at a third timing after a predetermined period from the first timing, and stopping the power supply fan and the main fan respectively. There line control to stop the sub fan in a fourth timing after a predetermined time period from said third timing,
The fixing temperature control means controls the temperature of the fixing means to be a temperature at which printing is performed during a print mode period in which printing is performed,
During the ready mode period starting from the first timing and ending with reception of the third timing or print data, control is performed to be a predetermined temperature lower than the temperature at which printing is performed,
The image forming apparatus is characterized in that control is not performed during a sleep mode period starting from the third timing and ending with reception of print data .