JP2010175834A - Wet type image forming apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wet type image forming apparatus and an image forming method, capable of effectively utilizing discarded carrier oil. <P>SOLUTION: The wet type image forming apparatus 1 includes a photoreceptor 10 and an intermediate transfer belt 21 carrying a toner image which is developed with wet type developer having toner particles dispersed in the carrier oil, and a fixing roller 5 fixing the toner image transferred from the intermediate transfer belt 21 on paper. The apparatus 1 comprises a cleaning device 15 and a cleaning device 30 collecting the carrier oil remaining on the photoreceptor 10 and the intermediate transfer belt 21 after transfer, and an oil application roller 105 supplying the collected carrier oil to a peripheral surface of a heating roller 51 of the fixing roller 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wet image forming apparatus such as a copying machine, a printer, or a facsimile machine, and an image forming method.

  In general, the wet image forming apparatus uses a wet developer (liquid developer) in which toner particles are dispersed in a carrier oil having high electrical resistance or insulation. In this wet type image forming apparatus, a photosensitive member (image carrier) is uniformly charged by a charging unit, the surface of the photosensitive member is exposed by an exposure unit, and an electrostatic latent image is formed by a developing unit. The toner image based on the above is developed with a wet developer, the toner image is transferred onto a sheet material such as paper or film by a transfer means, and the toner image is fixed on the sheet material by a fixing means having a fixing roller to form an image. An image forming method is also known in which a toner image formed on a photosensitive member is once transferred to an intermediate transfer member (image carrier) and then transferred to a sheet material.

  A wet image forming apparatus having such a configuration is disclosed in Patent Document 1, for example. According to Patent Document 1, in order to prevent an offset phenomenon in which a toner image adheres to the fixing roller side at the time of fixing, non-volatile oil is attached to the surface of the sheet material on the upstream side of the fixing roller to separate it from the fixing roller. What is provided with the non-volatile oil application | coating means which improves a moldability is disclosed.

JP-A-11-194621

  Incidentally, the carrier oil remaining on the photosensitive member or the intermediate transfer member after the toner image is transferred is collected by a cleaning device (collecting device) having a cleaning blade or the like. Although the recovered carrier oil is supplied again to the developing means and contributes to the development of the toner image, most of the recovered carrier oil is once stored in a waste liquid tank or the like and then discarded. Yes. Discarding the carrier oil has a problem that it costs not only the raw materials constituting the wet developer but also costs.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a wet image forming apparatus and an image forming method that can effectively use discarded carrier oil.

In order to solve the above problems, the present invention provides an image carrier that carries a toner image developed by a liquid developer in which toner particles are dispersed in carrier oil, and the toner image transferred from the image carrier. And a fixing roller for fixing the toner to the sheet material, the recovery device recovering the carrier oil remaining on the image carrier after the transfer, and the recovered carrier oil to the fixing roller. The structure which has the supply apparatus supplied to a surrounding surface is employ | adopted.
By adopting such a configuration, in the present invention, the carrier oil remaining on the image carrier can be reused as oil for improving the releasability of the fixing roller without being discarded.

In the present invention, a configuration is adopted in which a removal device for removing the toner particles remaining in the recovered carrier oil before the supply is provided.
By adopting such a configuration, the present invention reliably prevents toner remaining in the recovered carrier oil from being supplied to the fixing roller and adhering to the sheet material at the time of fixing, thereby causing image formation defects. Is possible.

In the present invention, the carrier oil is non-volatile.
By adopting such a configuration, in the present invention, the carrier oil can act as an oil that improves the releasability without being volatilized even when the fixing temperature of the fixing roller is high.

Further, in the present invention, the supply device includes a roller in which the carrier oil is accommodated inside and a plurality of through-holes that communicate the inside and the outside in the radial direction are formed; The structure which has an absorption member which is provided in a surrounding surface and absorbs the said carrier oil is employ | adopted.
By adopting such a configuration, in the present invention, the carrier oil accommodated inside from the peripheral surface of the roller oozes out and is stored in the storage member. An appropriate amount of carrier oil can be applied to the fixing roller by bringing the storage member into contact with the peripheral surface of the fixing roller.

In the present invention, a toner image developed by a liquid developer in which toner particles are dispersed in carrier oil is supported on an image carrier, and the toner image transferred from the image carrier is sheeted by a fixing roller. An image forming method comprising: a fixing step for fixing to a material; a recovery step for recovering the carrier oil remaining on the image carrier after the transfer; and the recovered carrier oil on a peripheral surface of the fixing roller. And a supply process for supplying.
By adopting such a configuration, in the present invention, the carrier oil remaining on the image carrier can be reused as oil for improving the releasability of the fixing roller without being discarded.

According to the present invention, an image carrier that carries a toner image developed by a liquid developer in which toner particles are dispersed in carrier oil, and a fixing that fixes the toner image transferred from the image carrier to a sheet material. A wet image forming apparatus including a roller, a recovery device for recovering the carrier oil remaining on the image carrier after the transfer, and a supply device for supplying the recovered carrier oil to a peripheral surface of the fixing roller By adopting the configuration, the carrier oil remaining on the image carrier can be reused as oil for improving the releasability of the fixing roller without discarding the carrier oil.
Therefore, the present invention has an effect of providing a wet image forming apparatus that can effectively use the discarded carrier oil.

1 is a schematic configuration diagram illustrating an example of a wet image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a flow path of a wet developer composed of toner and carrier oil of the wet image forming apparatus according to the embodiment of the present invention. It is a block diagram which shows the removal apparatus in embodiment of this invention. It is a block diagram which shows the oil application roller in embodiment of this invention. FIG. 5 is a sectional view taken along line XX in FIG. 4.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description, a case where the wet image forming apparatus of the present invention is applied to a color printer employing a tandem method will be described. However, the present invention is not limited to this, and for example, a copying machine, a facsimile, It can be suitably applied to a laser beam printer or the like. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

First, a schematic configuration of the wet image forming apparatus of the present invention will be described.
FIG. 1 is a schematic configuration diagram illustrating an example of a wet image forming apparatus 1 according to an embodiment of the present invention.
The wet image forming apparatus 1 is formed by an image forming unit 2 that forms an image using a wet developer (liquid developer), a paper feed cassette 3 that stores paper (sheet material), and the image forming unit 2. A secondary transfer unit 4 for transferring the image onto the paper, a fixing roller 5 for fixing the transferred image onto the paper, a paper discharge tray 6 for receiving the fixed paper, and a paper discharge tray from the paper feed cassette 3 And a transport unit 7 for transporting paper up to six.

  The image forming unit 2 includes an intermediate transfer belt 21 (image carrier) that runs endlessly, a cleaning device (collection device) 30 that cleans the intermediate transfer belt 21, yellow (Y), cyan (C), magenta ( M) and image forming units F (FY, FC, FM, FK) corresponding to the respective colors of black (BK).

The intermediate transfer belt 21 is stretched around a driving roller 22, a driven roller 23, a tension roller 24, and the like, and is configured to run endlessly clockwise in FIG.
The drive roller 22 is connected to a drive unit having a drive source such as a motor, and rotates while applying a grip force to the intermediate transfer belt 21. The driven roller 23 is driven to rotate following the rotational drive of the drive roller 22. The tension roller 24 is a kind of driven roller and applies tension to the intermediate transfer belt 21.
The cleaning device 30 includes a cleaning blade 31, a cleaning roller 32, and the like, and is configured to remove and collect carrier oil and toner remaining on the intermediate transfer belt 21.

The image forming unit F includes a photoconductor (image carrier) 10, a charger 11, an exposure device 12, a developing device 13, a primary transfer roller 14, a cleaning device (collecting device) 15, and a charge removal device 16. Is roughly provided.
The photoconductor 10 is formed in a cylindrical shape, and an electrostatic latent image and a toner image based on the electrostatic latent image are formed on the peripheral surface thereof. The charger 11 is disposed so as to face the photoconductor 10 and charges the peripheral surface of the photoconductor 10. The exposure device 12 scans the peripheral surface of the charged photoconductor 10 with laser light emitted based on image data in the print format. The developing device 13 develops a toner image based on the electrostatic latent image on the peripheral surface of the photoconductor 10 by supplying a wet developer to the peripheral surface of the photoconductor 10. The primary transfer roller 14 is disposed to face the photoconductor 10 with the intermediate transfer belt 21 interposed therebetween, and primarily transfers the toner image developed on the photoconductor 10 to the intermediate transfer belt 21. The cleaning device 15 includes a cleaning blade and the like, and removes and collects carrier oil and toner remaining on the photoreceptor 10. The neutralization device 16 neutralizes the surface of the photoreceptor 10 in preparation for image formation by the next round.

The paper feed cassette 3 can be pulled out with respect to the apparatus main body, and is configured to store paper.
The secondary transfer unit 4 performs secondary transfer of an image formed on the intermediate transfer belt 21 onto a sheet. The secondary transfer unit 4 drives the intermediate transfer belt 21 with the driving roller 22 and the intermediate transfer belt 21 interposed therebetween. A secondary transfer roller 41 disposed opposite to the roller 22 is provided.
The fixing roller 5 fixes the toner image secondarily transferred on the sheet by pressurizing and heating. The fixing roller 5 includes a heating roller 51 having a heating source therein and a pressure roller 52 that is in pressure contact with the heating roller 51. Prepare.
The transport unit 7 includes a pickup roller (not shown) for transporting paper from the paper feed cassette 3, a paper feed roller 72 for transporting paper, a paper discharge roller 73 for discharging paper to the paper discharge tray 6, and the like.

Subsequently, a configuration for supplying the carrier oil and the toner and the recovered carrier oil to the fixing roller 5 will be described with reference to FIG.
FIG. 2 is a diagram illustrating a distribution route of carrier oil and toner of the wet image forming apparatus 1 according to the embodiment of the present invention.
FIG. 3 is a configuration diagram illustrating the removal device 103 according to the embodiment of the present invention.
FIG. 4 is a configuration diagram showing the oil application roller (supply device) 105 in the embodiment of the present invention.
5 is a cross-sectional view taken along line XX in FIG.

The wet developer used in the present embodiment is a toner particle containing a binder resin and a colorant dispersed in a non-volatile, high electrical resistance carrier oil at a high concentration.
Examples of the binder resin constituting the toner particles include polyester resins, styrene resins, acrylic resins, and the like. A known pigment or dye can be used as the colorant. Examples thereof include black pigments such as carbon black, yellow pigments such as permanent yellow, red pigments such as permanent red, and blue pigments such as permanent blue.
As the carrier oil, a solvent having high electric resistance (for example, about 10 ⁴ to 10 ¹⁴ Ω), for example, Isopar G (registered trademark, manufactured by Exxon Chemical Co., Ltd.), hydrocarbon oils such as silicone oil, paraffin oil, and the like have a large molecular weight. Nonvolatiles are preferably used.

  As shown in FIG. 2, the wet image forming apparatus 1 includes a carrier tank 101 that stores carrier oil, and toners corresponding to yellow (Y), cyan (C), magenta (M), and black (BK). The containers 102Y, 102C, 102M, and 102K, the removal device 103 that removes toner particles remaining in the carrier oil collected by the cleaning device 15 and the cleaning device 30, and the carrier oil collected by the cleaning device 15 and the cleaning device 30 are accommodated. A waste liquid tank 104 and an oil application roller 105 that supplies carrier oil stored in the waste liquid tank 104 to the fixing roller 5 are provided.

  The carrier oil stored in the carrier tank 101 is supplied to the developing device 13 of each image forming unit F (FY, FC, FM, FK) through pipes 106Y, 106C, 106M, 106K branched from the pipe 106. It has become. The pipes 106Y, 106C, 106M, and 106K are provided with valves 107Y, 107C, 107M, and 107K that adjust the supply amount of the carrier oil, respectively.

  The toners stored in the toner containers 102Y, 102C, 102M, and 102K are supplied to the developing device 13 of the image forming unit F corresponding to each color through the pipes 108Y, 108C, 108M, and 108K, respectively. Further, valves 109Y, 109C, 109M, and 109K for adjusting the supply amount of toner are provided in the pipes 108Y, 108C, 108M, and 108K, respectively.

The removing device 103 is provided on the downstream side of the cleaning device 15 and the cleaning device 30, respectively. As shown in FIG. 3, the removing device 103 includes a storage part 131 for temporarily storing the recovered carrier oil (the symbol L in FIG. 3 indicates carrier oil), and a metal member 132 provided inside the storage part 131. The power supply 133 applies a bias having a polarity opposite to that of the charged toner particles on the metal member 132, and the pipe 134 is connected to the bottom of the reservoir 131.
The removing device 103 configured as described above temporarily stores the recovered carrier oil in the storage unit 131 and applies a bias to the cylindrical metal member 132 to electrically supply toner particles in the carrier oil to the peripheral surface thereof. Attraction and toner particles are removed (in FIG. 4, the symbol T indicates toner particles).
The removing device 103 is not limited to the above-described configuration, and may be configured to remove the toner particles in the carrier oil through the filter, or the toner is applied to a metal filter formed in a fine mesh shape. A configuration in which a toner particle removal efficiency is increased by using a configuration in which a bias having a polarity opposite to that of the particles is applied may be used.

As shown in FIG. 2, the carrier oil that has passed through the removing device 103 provided on the downstream side of the cleaning device 30 circulates through a pipe 134 and is supplied to the waste liquid tank 104.
On the other hand, the carrier oil that has passed through the removing device 103 provided on the downstream side of the cleaning device 15 flows through the pipes 134Y, 134C, 134M, and 134K, and is supplied to the waste liquid tank 104 or the developing device 13. The pipes 134Y, 134C, 134M, and 134K are provided with valves 135Y, 135C, 135M, and 135K, respectively, so that the carrier oil distribution path is switched to the waste liquid tank 104 or the developing device 13.

The oil application roller 105 and the waste liquid tank 104 are connected by a pipe 110. The piping 110 is provided with a pump 111.
The oil application roller 105 applies the recovered carrier oil to the peripheral surface of the heating roller 51 that constitutes the fixing roller 5. As shown in FIG. 4, the oil application roller 105 rotates around the rotation axis parallel to the rotation axis of the heating roller 51. A rotatable roller 151, and an absorption member 152 provided on the peripheral surface of the roller 151.

As shown in FIG. 5, the roller 151 has a hollow space in which the recovered carrier oil supplied via the pipe 110 can be accommodated (in FIG. 5, the symbol L indicates the carrier). Oil). In addition, the roller 151 has a plurality of through holes 153 penetrating the inside and the outside in a radial direction perpendicular to the rotation axis (radially spaced from the rotation axis by a predetermined angle). Further, the through holes 153 are formed so as to form a row along the rotation axis direction of the rollers 151.
The storage member 152 is configured by a member that stores carrier oil that oozes from the roller 151, such as a felt, sponge, or cloth.

Next, the operation (image forming method) of the wet image forming apparatus 1 having the above configuration will be described.
As shown in FIG. 1, the wet image forming apparatus 1 uniformly charges the photoconductor 10 with a charger 11, exposes the surface of the photoconductor 10 with an exposure device 12, forms an electrostatic latent image, and develops it. The toner image based on the electrostatic latent image is developed with a wet developer by the device 13, and the toner image is carried on the photoreceptor 10. The toner image carried on the photoconductor 10 is primarily transferred to the intermediate transfer belt 21 by the primary transfer roller 14. The cleaning device 15 collects the carrier oil remaining on the photoconductor 10 after the primary transfer with a cleaning blade or the like (collection process).

As shown in FIG. 2, the carrier oil collected by the cleaning device 15 is introduced into a removing device 103 provided on the downstream side. The removing device 103 temporarily stores the recovered carrier oil in the bowl-shaped storage 131 in a cross-sectional view shown in FIG. The reservoir 131 removes the toner particles by electrically adsorbing the toner particles remaining in the carrier oil collected by the metal member 132 biased by the power supply 133 (removal step).
The carrier oil from which the toner particles have been removed is supplied to the waste liquid tank 104 via pipes 134Y, 134C, 134M, and 134K (see FIG. 2) connected to the bottom of the reservoir 131, respectively. The carrier oil from which the toner particles have been removed may be supplied again to the developing device 13 and reused.

  On the other hand, the toner images primarily transferred from the photosensitive member 10 and carried on the intermediate transfer belt 21 are superposed with yellow, cyan, magenta, and black toner images by the image forming units F and supplied by the secondary transfer unit 4. Secondary transfer is performed collectively on the paper carried out of the paper cassette 3. The cleaning device 30 collects the carrier oil remaining on the intermediate transfer belt 21 after the secondary transfer by the cleaning blade 31 and the cleaning roller 32 (collection process). Then, the recovered carrier oil is introduced into the removing device 103 to remove the toner particles (removing step), and is supplied to the waste liquid tank 104 through the pipe 134. Since the toner particles of each color are mixed in the carrier oil collected from the intermediate transfer belt 21, the removing device 103 provided on the downstream side of the cleaning device 30 is the removing device 103 provided on the downstream side of the cleaning device 15. It is desirable that the configuration has higher removal efficiency.

  The carrier oil stored in the waste liquid tank 104 is supplied to the oil application roller 105 via the pipe 110 by the pump 111. The oil application roller 105 stores the supplied carrier oil in the roller 151. When the roller 151 rotates, the carrier oil oozes out from the inside through the plurality of through holes 153. The carrier oil that has oozed out is stored in the storage member 152. The oil application roller 105 supplies carrier oil to the peripheral surface of the heating roller 51 by rotating the storage member 152 in contact with the peripheral surface of the heating roller 51 (supply process).

  The fixing roller 5 heats and presses the paper on which the toner image is secondarily transferred by the heating roller 51 and the pressure roller 52 (fixing step). At this time, since the carrier oil is applied to the peripheral surface of the heating roller 51, the releasability is improved, the phenomenon that the toner image is offset to the heating roller 51 side is suppressed, and a smooth fixing operation is performed. It will be.

Therefore, according to the above-described embodiment, the photosensitive member 10 and the intermediate transfer belt 21 that carry the toner image developed by the wet developer in which the toner particles are dispersed in the carrier oil, and the image transferred from the intermediate transfer belt 21 are transferred. A wet image forming apparatus 1 including a fixing roller 5 for fixing a toner image on a sheet, and a cleaning device 15 and a cleaning device 30 for collecting carrier oil remaining on the photosensitive member 10 and the intermediate transfer belt 21 after the transfer; By adopting a configuration that includes an oil application roller 105 that supplies the recovered carrier oil to the peripheral surface of the heating roller 51 of the fixing roller 5, the carrier oil remaining on the photosensitive member 10 and the intermediate transfer belt 21 is discarded. And can be reused as oil to improve the releasability of the fixing roller 5 To become.
Therefore, in this embodiment, there is an effect that it is possible to provide the wet image forming apparatus 1 that can effectively use the discarded carrier oil.

  Further, in the present embodiment, by adopting a configuration in which the removal device 103 that removes toner particles remaining in the collected carrier oil before the supply is provided, the toner remaining in the collected carrier oil is fixed. It is possible to reliably prevent an image formation failure caused by being supplied to the roller 5 and adhering to the sheet at the time of fixing.

  Further, in the present embodiment, by adopting a configuration in which the carrier oil is non-volatile, the carrier oil does not volatilize even when the fixing temperature of the heating roller 51 is high, and the releasability is improved. It can act as an oil to make.

  Further, in the present embodiment, the oil application roller 105 includes a roller 151 in which a plurality of through-holes 153 are formed to accommodate the carrier oil and communicate the inside and the outside in the radial direction. By adopting a configuration in which a storage member 152 that absorbs carrier oil is provided on the peripheral surface of the roller 151, the carrier oil accommodated inside the peripheral surface of the roller 151 oozes out to the storage member 152. It is possible to apply an appropriate amount of carrier oil to the fixing roller 5 by bringing the storage member 152 into contact with the peripheral surface of the fixing roller 5.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above embodiment, it has been described that the oil application roller 105 is used as the supply device. However, the present invention is not limited to the above configuration, and for example, the recovered carrier oil is soaked into the peripheral surface of the heating roller 51. A configuration in which the felt, sponge, cloth, or the like is brought into contact to supply carrier oil, or a configuration in which carrier oil is supplied by spraying with a sprayer may be used.

  Further, for example, in the above-described embodiment, it has been described that the removing device is provided on the downstream side of each cleaning device 15 and the cleaning device 30. However, a configuration in which the removing device is provided in the waste liquid tank 104 to remove toner particles collectively. Alternatively, a configuration may be adopted in which a removal device is provided in the pipe 110 connecting the waste liquid tank 104 and the oil application roller 105 to remove toner particles collectively.

  DESCRIPTION OF SYMBOLS 1 ... Wet image forming apparatus, 5 ... Fixing roller, 10 ... Photoconductor (image carrier), 15 ... Cleaning device (collection device), 21 ... Intermediate transfer belt (image carrier), 30 ... Cleaning device (collection device) DESCRIPTION OF SYMBOLS 103 ... Removal apparatus 105 ... Oil application roller (supply apparatus) 151 ... Roller, 152 ... Absorption member, 153 ... Through-hole, T ... Toner particle, L ... Carrier oil

Claims (8)

A wet image comprising: an image carrier that carries a toner image developed by a liquid developer in which toner particles are dispersed in carrier oil; and a fixing roller that fixes the toner image transferred from the image carrier to a sheet material. A forming device,
A collection device for collecting the carrier oil remaining on the image carrier after the transfer;
A wet image forming apparatus comprising: a supply device that supplies the recovered carrier oil to a peripheral surface of the fixing roller.   The wet image forming apparatus according to claim 1, further comprising a removing device that removes the toner particles remaining in the collected carrier oil before the supply.   The wet image forming apparatus according to claim 1, wherein the carrier oil is non-volatile.   The supply device accommodates the carrier oil inside and has a roller formed with a plurality of through holes for communicating the inside and the outside in a radial direction, and the carrier is provided on a peripheral surface of the outside roller. The wet image forming apparatus according to any one of claims 1 to 3, further comprising a storage member that stores oil. A fixing step in which a toner image developed by a liquid developer in which toner particles are dispersed in carrier oil is supported on an image carrier, and the toner image transferred from the image carrier is fixed on a sheet material by a fixing roller; An image forming method comprising:
A recovery step of recovering the carrier oil remaining on the image carrier after the transfer;
And a supplying step of supplying the recovered carrier oil to the peripheral surface of the fixing roller.   6. The image forming method according to claim 5, further comprising a removing step of removing the toner particles remaining in the collected carrier oil before the supplying step.   The image forming method according to claim 5, wherein the carrier oil is non-volatile.   In the supplying step, the carrier oil is accommodated inside and a roller having a plurality of through-holes communicating the inside and the outside in a radial direction, and the carrier provided on a peripheral surface of the outside roller 8. The image forming method according to claim 5, wherein the collected carrier oil is supplied to a peripheral surface of the fixing roller using a storage member that stores oil. 9. .

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