JP2006154217A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can maintain high productivity by quickly restoring temperature control of a fixing device and reducing the down time for restoration from jam. <P>SOLUTION: The image forming apparatus includes: a plurality of fixing means for fixing a toner image formed on a sheet material; drawing means for allowing the plurality of fixing means to be drawn out of a main body apparatus independently of one another; and a lock means for forbidding each of the drawing means to be drawn, and two or more fixing means are forbidden to be simultaneously drawn. A fixing device caused to perform jam processing is supported in the image forming apparatus having the plurality of fixing devices, and temperature control of the fixing device is allowed to be quickly restored to reduce the down time for restoration from jam, and thus high productivity is maintained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet material.

  In an image forming apparatus, an unfixed image drawn on a sheet with toner is generally fixed on a sheet surface by heat and pressure in a fixing device. The fixing device is heated by an internal heater, and is controlled so as to maintain a temperature necessary for fixing while supplementing an amount of heat taken by the passing sheet.

  The number of sheet materials conveyed by image forming devices has been increasing year by year. With a configuration in which image fixing is performed with a single fixing unit, both stable fixing properties, fixed image quality, and productivity are achieved for all materials. To make it difficult. In order to cope with this, a technique has been adopted in which a plurality of fixing devices are arranged in series in the conveyance path to avoid problems caused by the single fixing device configuration, such as insufficient heat.

  A typical conventional example will be described below.

  FIG. 7 is a schematic cross-sectional view of an image forming apparatus having two fixing devices. The conveyance path through which the sheet is conveyed from the image forming unit to the first fixing unit 20 is connected to the second fixing unit 21 downstream of the first fixing unit 20 and is transferred to the sheet discharging unit 22, and is discharged to the sheet discharge tray 23. To be loaded.

  When performing double-sided image formation, after exiting the fixing device 21, the paper is guided to a conveyance path 45 by a flapper (not shown), and is reversed to form a double-sided image through a double-sided path 46.

  Patent Documents 1 and 2 propose an apparatus using a plurality of fixing means.

JP 07-271226 A Japanese Patent Laid-Open No. 06-348159

  In this way, in an image forming apparatus having a plurality of fixing devices, when jamming of a plurality of fixing devices is performed, it takes time until the temperature adjustment of the fixing device that has once been turned off returns to a predetermined temperature. As a result, the downtime of the apparatus increases. In addition, when the set temperatures are different among a plurality of fixing devices, it takes time to recover when the temperature of the fixing device having a higher setting temperature is lowered, and this time determines the time until the recovery. .

  The present invention has been made in view of the above-described problems, and the object of the present invention is to enable the temperature adjustment of the fixing device to be quickly restored, to reduce downtime upon restoration from jamming, and to maintain high productivity. An object of the present invention is to provide an image forming apparatus capable of performing the above.

  In order to achieve the above object, the present invention provides a plurality of fixing means for fixing a toner image formed on a sheet material to the sheet material, and the plurality of fixing means can be independently pulled out from the main unit. And a lock unit that prohibits pulling out of each of the pulling units, and two or more fixing units are prohibited from being pulled out at the same time.

  According to the present invention, in an image forming apparatus having a plurality of fixing devices, a fixing device that performs jam processing is supported so that the temperature adjustment of the fixing device can be quickly returned, and downtime upon returning from the jam is reduced. High productivity can be maintained.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a printer main body, and an upper portion of the printer main body 1 has primary colors of four colors of yellow, magenta, cyan, and black. Engine parts Y, M, C, and BK for forming an image are arranged. Print data transmitted from an external device such as a personal computer is received by the controller 3 that controls the printer body 1 and is output to the laser scanner 10 for each color as write image data.

  The laser scanner emits a laser beam onto the photosensitive drum 12 and draws an optical image according to the written image data.

  The primary image forming unit of each color includes a photosensitive drum 12, a charger 13 for uniformly charging the surface of the photosensitive drum 12, and the laser scanner 11 on the surface of the photosensitive drum 12 charged by the charger 13. A developing device 14 for developing an electrostatic latent image created by drawing an optical image into a toner image to be transferred to an intermediate transfer belt, and an intermediate transfer of a toner image developed on the surface of the photosensitive drum 12 A primary transfer roller 19 for transferring to the belt 16 and a cleaner (not shown) for removing toner remaining on the photosensitive drum 12 after transferring the toner image. The toner image primarily transferred to the intermediate transfer belt 16 is retransferred onto the sheet by the secondary transfer roller 17. The toner remaining without being transferred by the secondary transfer roller 17 is collected by the cleaner 18.

  The sheet feeding unit 30 is positioned at the uppermost stream of sheet conveyance, and in the printer of the present embodiment, two stages are provided at the lower part of the apparatus (30a, 30b). The sheet fed from the sheet feeding unit is conveyed downstream through the vertical conveyance path 36. At the most downstream position of the vertical conveyance path 36, there is a registration roller pair 40, where final skew correction of the sheet and timing adjustment of image writing and sheet conveyance in the image forming unit are performed.

  On the downstream side of the image forming unit, a first fixing device 20 for fixing the toner image on the sheet S as a permanent image, and a first fixing device for performing additional fixing on the sheet that has passed through the first fixing device 20. A two fixing device 21 is provided.

  A flapper (not shown) capable of switching the conveyance path after passing through the second fixing device 21 is provided, and a double-sided conveyance path can be selected according to a request signal from the controller 3. A sheet reversing unit 45 that also serves as an entrance to a duplex conveyance path 46 for duplex printing, and a discharge roller 22 for discharging the sheet S on which an image has been fixed from the printer body 1 are provided. A paper discharge tray 23 for receiving the sheet S discharged by the discharge roller 22 is configured.

  Details of the fixing structure according to the present invention will be described below.

  2 and 3 are schematic cross-sectional views of the fixing configuration in the present embodiment. The fixing structure including the first fixing device 20 and the second fixing device 21 is as outlined above, and the distance between the first fixing device 20 and the second fixing device 21 is longer than the longest sheet used in the printer body. The sheet is long and prevents the sheet from straddling the first fixing device 20 and the second fixing device 21.

  The first fixing device 20 and the second fixing device 21 are provided with rail members 50 and 51 on the main body so that the first fixing device 20 and the second fixing device 21 can be pulled out toward the front side of the printer main body, respectively, and receiving members for the first fixing device 20 and the second fixing device 21. It can be pulled out independently by the pulling means 54 and 55 constituted by 52 and 53. The receiving members 52 and 53 are provided with rollers 57a and 57b and can move on the rail member 50 (FIG. 3).

  Fixing units remaining in the main body other than the fixing unit pulled out by jamming or the like have a temperature adjustment control circuit for independently maintaining the temperature adjustment of the fixing unit, and as shown in FIG. The exhaust ducts 60 and 61 and the exhaust fans 62 and 63 are provided so as to surround the second fixing device 21 and adjust the temperature.

  Instruction means 70 and 71 for instructing jam processing are provided in the vicinity of the fixing device to instruct which fixing device is to perform jam processing first. Of course, this indicator member may be placed by placing a small liquid crystal display near the fixing unit to instruct jamming of the fixing device, or may be instructed by an operation unit or the like attached to the main body 1. The instructed fixing device 20 is in a state in which the fixing device can be pulled out when the locking means 80 is released and the engagement with the fixing device is released (80a). 80b written by a broken line prohibits the fixing unit from being pulled out in a state where the locking means is engaged with the engagement 84 and locked (FIG. 3).

  The order of the jam processing of the fixing device is performed from the one that takes time to return to the set temperature of the fixing device.

  For example, if the first fixing device 20 has a higher set temperature than the second fixing device 21 with the same heat capacity and the same heater power, the first fixing device 20 is instructed to jam first.

  This is because the fixing device having a higher temperature setting takes more time to raise the temperature, so that the jam processing is performed first, and then the temperature adjustment is started immediately and the temperature is returned to the predetermined temperature. The start of temperature adjustment is controlled by the control means so as to cooperate with the lock means 80 and 81 provided in each fixing device. When it is confirmed by a detecting means (not shown) for detecting that the jamming process is completed and the fixing device is pushed into the main body and the fixing device is set, the locking means 80 and 81 are locked, and the fixing heater is energized to adjust the temperature. Start. The fixing unit other than the fixing unit instructed to perform jam processing is locked by the locking means and prohibits the fixing unit from being pulled out. The lock means 80 and 81 are moved by a solenoid or the like.

  FIG. 4 is a table showing changes in fixing temperature with respect to recovery of jam processing.

The set temperature T1 of the first fixing device 20 and the set temperature T2 of the second fixer 21 are T1> T2
It has become. The time to rise to a predetermined temperature is gained by adjusting the temperature by first performing the jam processing of the first fixing device 20 having a high set temperature.

  When a jam of the first fixing device 20 and the second fixing device 21 is detected by a sensor paper (not shown) provided in the fixing device, the energization to the fixing heater of the fixing device is stopped, and the first fixing device 20 The lock unit 80 is released, and jamming is instructed by the blinking of the instruction unit 70. The first fixing device 20 is pulled out to the front side of the main body 1, the jam processing of the first fixing device 20 is finished, and when the setting of the first fixing device 20 is detected, the locking means 80 is locked.

  If it is detected that a jam has occurred in the second fixing device 21, the lock unit 81 is released and an instruction unit 71 instructs. The second fixing device 21 is pulled out to the front side of the main body 1, the jam processing of the second fixing device 21 is finished, and when the setting of the second fixing device 21 is detected, the lock unit 81 is locked and temperature adjustment is started. At this time, since the first fixing device 20 has already reached the predetermined temperature T1, when the second fixing device 21 reaches the predetermined temperature T2, the first fixing device 20 can return to the operable state of the apparatus.

  When no jam is detected by the second fixing device 21, the temperature of the second fixing 21 is adjusted while maintaining the predetermined temperature T2.

  As a result, the fixing device can efficiently control the recovery.

  When the fixing roller or the like is replaced during maintenance of the apparatus main body or the like, a release mode is also provided in which the lock means 80 and 81 are released simultaneously.

<Embodiment 2>
In the first embodiment, the system in which the fixing devices are arranged in series has been described. However, as shown in FIGS. 5 and 6, the same effect can be obtained with a configuration in which the fixing devices are arranged in parallel. . Those described in the first embodiment shown in the figure have the same numbers and will not be described.

  Hereinafter, Embodiment 2 in which fixing devices are arranged in parallel will be described.

  The sheet S is sorted and sent to the first fixing device 24 and the second fixing device 25 arranged above and below by a flapper upstream.

  As the first fixing 24 and the second fixing 25, a fixing device having different functions and a color fixing unit and a monochrome fixing unit or a belt fixing unit for one can be easily considered.

  The first fixing device 24 and the second fixing device 25 can be pulled out independently by the pulling means 55 and 56 as in the first embodiment.

  The fixing devices remaining in the main body other than the fixing device pulled out by jamming or the like have a temperature adjustment control circuit that independently maintains the temperature adjustment of the fixing device, and the first fixing device 24 and the second fixing device 25. Exhaust ducts 64 and 65 and exhaust fans 66 and 67 are provided so as to surround each of them, and the temperature is adjusted.

  Instruction members 72 and 73 for instructing jam processing are provided in the vicinity of the fixing device to instruct which fixing device is to perform jam processing first. The order of the jam processing of the fixing device is performed from the one that takes time to return to the set temperature of the fixing device.

  The start of temperature adjustment is controlled by the control means so as to cooperate with the lock means 82 and 83 provided in each fixing device, and detection that detects that jamming is completed and the fixing device is set by pushing the fixing device into the main body. Locks when confirmed by means (not shown). Other than the fixing device instructed to perform the sham processing, the fixing unit locks the fixing device and prohibits the fixing device from being pulled out. The lock means 82 and 83 are moved by a solenoid or the like.

1 is a cross-sectional view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional arrangement diagram illustrating a fixing configuration of the image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a cross-sectional arrangement diagram illustrating a fixing configuration of the image forming apparatus according to the first embodiment of the present invention. Change in fixing temperature according to the first embodiment of the present invention It is sectional drawing of the image forming apparatus which concerns on Embodiment 2 of this invention. FIG. 5 is a cross-sectional arrangement diagram illustrating a fixing configuration of an image forming apparatus according to a second embodiment of the present invention. It is sectional drawing of the conventional image forming apparatus.

Explanation of symbols

20, 24 First fixing device 21, 25 Second fixing device 52, 53, 55, 46 Pulling means 70, 71, 72, 73 Instructing means 80, 81, 82, 83 Locking means

Claims (13)

  A plurality of fixing means for fixing the toner image formed on the sheet material to the sheet material, a drawing means capable of independently pulling out the plurality of fixing means from the main body device, and a drawing of each drawing means And an image forming apparatus characterized in that it is prohibited to pull out two or more fixing means simultaneously.   The image forming apparatus according to claim 1, further comprising: a control unit configured to adjust a temperature of each of the plurality of fixing units in a state where the fixing unit other than the pulled out fixing unit is set in the main body.   3. The image forming apparatus according to claim 2, wherein in the plurality of fixing units, each fixing unit includes an exhaust fan and a fixing temperature control unit in order to maintain temperature control independently.   The image forming apparatus according to claim 1, wherein the plurality of fixing units include an instruction member or a display unit that indicates an order or place of jam processing.   5. The image forming apparatus according to claim 1, wherein the plurality of fixing units include an instruction member or a display unit that indicates an order or place of jam processing.   6. The image forming apparatus according to claim 5, wherein the order in which the jam processing is performed in the plurality of fixing units is set in descending order of the fixing set temperature.   6. The image forming apparatus according to claim 5, wherein in the plurality of fixing units, the order in which the jam processing is performed is performed first from the one having the longest return time to the fixing set temperature.   6. The image forming apparatus according to claim 5, wherein in the plurality of fixing units, the order in which the jam processing is performed is performed first from the smallest fixing heater wattage.   6. The image forming apparatus according to claim 5, wherein in the plurality of fixing units, the order in which the jam processing is performed is performed in descending order of the fixing heat capacity.   The image forming apparatus according to claim 1, wherein, in the plurality of fixing units, a locking unit that locks the drawing or opening of the fixing unit other than the fixing unit that performs jam processing.   11. The image forming apparatus according to claim 10, wherein the fixing unit having the lock unit starts temperature adjustment when the lock unit is locked.   12. The image forming apparatus according to claim 1, wherein a distance between the fixing unit and the fixing unit is equal to or longer than a longest sheet length of the apparatus in the plurality of fixing units.   12. The image forming apparatus according to claim 10, wherein the lock unit has a mode in which the lock is invalidated and temperature adjustment of the fixing unit is stopped.

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