JP2011197317A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that prevents a reduction in fixation strength caused by a solvent of a liquid developer, even when an amount of a curable compound in the liquid developer is reduced.SOLUTION: The image forming apparatus 100 includes: a photoreceptor 10; an exposure device 14 configured to form a latent image on the surface of the photoreceptor; a developing unit 20 configured to develop the latent image formed on the surface of the photoreceptor 10, by the liquid developer 16 containing toner particles and the solvent and form a toner image 18; a transfer roll 40 configured to transfer the toner image 18 formed on the surface of the photoreceptor 10, onto a recording medium 30; a fixing device 40 configured to fix the toner image 18 transferred onto the recording medium 30, to the recording medium 30 to form a fixed image 32; a curable compound applying means 28 configured to apply the curable compound 26 to at least one of the toner image 18 and the fixed image 32; and a polymerization accelerator applying means 38 configured to apply a polymerization accelerator 36 to at least one of the toner image 18 and the fixed image 32.

Description

  The present invention relates to an image forming apparatus.

Patent Document 1 discloses a technique for removing a solvent (carrier oil) contained in a liquid developer from an unfixed toner image before fixing in image formation using the liquid developer.
Patent Document 2 discloses a liquid developer having an unsaturated fatty acid triglyceride (vegetable oil) as a carrier solvent.

Patent Documents 3 to 6 disclose a liquid developer containing a crosslinking agent or a monomer having a reactive unsaturated group, and a photopolymerization initiator.
Patent Documents 7 and 8 disclose a fixing device in which an unsaturated fatty acid is contained in carrier oil and an oxidative polymerization accelerator is supplied from a fixing roller.
Patent Document 9 and Patent Document 10 disclose a technique in which a carrier oil containing an unsaturated fatty acid having a reactive unsaturated group or a semi-dry oil is used and cured by heat fixing and ultraviolet irradiation. .

Patent Document 11 discloses a liquid toner for developing an electrostatic latent image, which contains an oil having an iodine value of 130 or more.
Patent Document 12 discloses an image having a coating means for coating a non-fixed image on a recording medium with a dispersion promoting substance having a reactive group contained in a developer and a substance that reacts with the reactive group in the dispersion promoting substance. A fixing device is disclosed.

JP 2003-167456 A JP 2006-276787 A JP 2006-056946 A JP 2002-251040 A JP 2003-057883 A JP 2009-175242 A JP 2007-139829 A JP 2007-139994 A JP2007-188024A JP 2007-188025 A JP-A-8-272153 JP 2005-265933 A

  An object of the present invention is to provide an image forming apparatus in which a decrease in fixing strength due to a solvent of a liquid developer is suppressed.

The above problem is solved by the following means. That is,
The invention according to claim 1
A latent image carrier,
Latent image forming means for forming a latent image on the surface of the latent image holder;
Developing means for developing the latent image formed on the surface of the latent image holding member with a liquid developer containing toner particles and a solvent to form a toner image;
Transfer means for transferring the toner image formed on the surface of the latent image holding member onto a recording medium;
Fixing means for fixing the toner image transferred to the recording medium to the recording medium to form a fixed image;
A curable compound applying means for applying a curable compound to at least one of the toner image and the fixed image;
An image forming apparatus comprising: a polymerization accelerator applying unit that applies a polymerization accelerator to at least one of the toner image and the fixed image.

The invention according to claim 2
2. The polymerization accelerator applying means according to claim 1, wherein the polymerization accelerator applying means is a means for applying a polymerization accelerator directly and non-contact to at least one of the toner image and the fixed image transferred onto the recording medium. This is an image forming apparatus.

The invention according to claim 3
The image forming apparatus according to claim 1, wherein the curable compound is a dry oil.

  According to the first aspect of the present invention, a decrease in fixing strength is suppressed as compared with a case where no curable compound imparting means is provided.

  According to the invention of claim 2, the polymerization accelerator applying means has a member for applying the polymerization accelerator in contact with at least one of the toner image and the fixed image transferred onto the recording medium. , Image density unevenness is suppressed.

  According to the third aspect of the present invention, image density unevenness is suppressed as compared with a mode in which a liquid developer containing a drying oil is used as the curable compound without providing the curable compound providing means.

1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment. It is a schematic block diagram which shows the image forming apparatus which concerns on 2nd Embodiment. It is a schematic block diagram which shows the image forming apparatus which concerns on 3rd Embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Embodiments according to the invention will be described below with reference to the drawings. However, specific contents of the following embodiments can be appropriately changed without departing from the spirit of the invention. In addition, the same code | symbol is provided to the member which has the same effect | action and function through all the drawings, and the overlapping description may be abbreviate | omitted.

<First Embodiment>
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the first embodiment. In the image forming apparatus of the first embodiment, in the image forming apparatus using a liquid developer, the curable compound is directly applied to the toner image on the intermediate transfer roll, and the polymerization accelerator is applied to the toner image on the recording medium before fixing. An image forming apparatus for forming a monochromatic image directly applied.

The image forming apparatus 100 forms an electrostatic latent image (latent image) by exposing the surface of the photoconductor 10 to the photoconductor 10 (electrostatic latent image holding body), a charging device 12 for charging the surface of the photoconductor 10. The exposure device 14 (the charging device 12 and the exposure device 14 is an example of a latent image forming unit) and the latent image formed on the surface of the photoreceptor 10 are developed with a liquid developer 16 containing toner particles 16A and a solvent 16B. , A developing device 20 (developing means) for forming the toner image 18, an intermediate transfer roll 22 to which the toner image 18 formed by the developing device 20 is transferred from the photoconductor 10, toner or dust adhering to the photoconductor 10, etc. The photoconductor cleaning member 24 for removing the photoconductor and the static eliminator 46 for neutralizing the photoconductor 10.
The image forming apparatus 100 also includes a curable compound applying device 28 (curable compound applying unit) that applies a curable compound 26 to the toner image 18 on the intermediate transfer roll 22, and a toner image 18 provided with the curable compound 26. A transfer roll 34 (transfer means) for transferring the toner to the recording medium 30, a polymerization accelerator applying device 38 (polymerization accelerator applying means) for applying a polymerization accelerator 36 to the toner image 18 on the recording medium 30, and a polymerization accelerator. And a fixing device 40 (fixing means) for fixing the toner image 18 provided with 36 to the recording medium 30.

Specifically, in the image forming apparatus 100, the charging device 12, the exposure device 14, the developing device 20, the intermediate transfer roll 22, the photoconductor cleaning member 24, and the charge removal device are clockwise around the photoconductor 10. 46 is arranged.
A curable compound applying device 28 and a transfer roll 34 are arranged around the intermediate transfer roll 22 in a counterclockwise direction so as to pass through a position sandwiched between the intermediate transfer roll 22 and the transfer roll 34. A conveyance belt 42 that conveys the recording medium 30 in the direction of arrow E (conveyance direction) is disposed. That is, when the toner image 18 on the intermediate transfer roll 22 is transferred to the recording medium 30, for example, the intermediate transfer roll 22 comes into contact with the transfer roll 34 via the recording medium 30 and the conveyance belt 42.

  A fixing device 40 is disposed on the downstream side of the conveyance belt 42 in the conveyance direction. The fixing device 40 includes a fixing roll 41 and a pressure roll 43, and the conveyance belt 42 is sandwiched between the fixing roll 41 and the pressure roll 43. That is, when the toner image 18 is fixed on the recording medium 30 by the fixing device 40, for example, the fixing roll 41 is in direct contact with the toner image 18 on the recording medium 30, and the pressure roll 43 is in direct contact with the conveyance belt 42. The pressure roll 43 applies pressure to the fixing roll 41 via the conveyance belt 42 and the toner image 18.

  As described above, the intermediate transfer roll 22, the polymerization accelerator applying device 38, and the fixing roll 41 (fixing member) of the fixing device 40 are arranged in the direction of arrow E on the intermediate transfer roll 22 side of the transport belt 42. Yes. A pressure roll 43 is disposed on the opposite side of the conveyance belt 42 from the fixing roll 41, and the conveyance belt 42 and the recording medium 30 are disposed between the fixing roll 41 and the pressure roll 43.

Examples of the photoconductor 10 include a photoconductor drum having a single layer structure or a multi-layer structure, but the photoconductor drum is not limited to this, and a photoconductor belt or the like may be used. Examples of the photoreceptor drum include inorganic photoreceptors such as selenium and amorphous silicon, or organic photoreceptors.
The charging device 12 is not limited to a non-contact type charging device as in the present embodiment, and may be of a type that contacts and charges the photoreceptor 10. Specific examples of the charging device 12 include a charging roll and a corotron.
The exposure device 14 irradiates the surface of the photoconductor 10 with light and writes an image. For example, a method of scanning a laser beam generated by a laser generator with a polygon mirror, an organic electroluminescent element or a light emitting diode is used. Exposure apparatus such as a conventional method.

  As shown in FIG. 1, the developing device 20 includes, for example, a developing roll 20A, a developer storage container 20B, and a regulating member 20C. Further, the developing roller 20A has, for example, a toner particle 16A and a solvent 16B in which a part of the surface faces the surface of the photoreceptor 10 and the other part of the surface is accommodated in the developer storage container 20B. Is disposed so as to be immersed in the liquid developer 16 containing The regulating member 20C is provided to control the amount of the liquid developer 16 that adheres to the surface of the developing roll 20A, for example. The developing device 20 is not limited to the above-described configuration as long as the surface of the photoconductor 10 is developed, and may be a device that is not provided with the regulating member 20C, for example.

As the intermediate transfer roll 22 and the transfer roll 34, for example, a metal core provided with an elastic layer such as rubber, or a metal core provided directly or directly with a metal core with an elastic layer is coated with resin or metal plating. And those that have been applied.
In this embodiment, the intermediate transfer roll 22 is used as the intermediate transfer member and the transfer roll 34 is used as the transfer device. However, the present invention is not limited to this. For example, an intermediate transfer belt may be used instead of the intermediate transfer roll 22. Instead of the transfer roll 34, a transfer belt may be used. In this embodiment, the intermediate transfer roll 22 contacts the photoconductor 10 and the toner image 18 is transferred from the photoconductor 10 to the intermediate transfer roll 22. However, the present invention is not limited to this. May be transferred. Further, in the present embodiment, the transfer roll 34 is in contact with the intermediate transfer roll 22 via the conveyance belt 42 and the recording medium 30, and the toner image 18 is transferred from the intermediate transfer roll 22 to the recording medium 30. However, the present invention is not limited to this, and a system in which the toner image 18 is transferred in a non-contact manner may be used.

Examples of the photoconductor cleaning member 24 include a cleaning blade or a cleaning brush, but the photoconductor cleaning member 24 is not limited to this, and the photoconductor cleaning member 24 may not be provided.
The static eliminator 46 is not particularly limited as long as it removes the potential remaining on the surface of the photoconductor 10, and may be in a form without the static eliminator 46.

  The fixing device 40 includes the fixing roll 41 and the pressure roll 43 as described above. Specific examples of the fixing roll 41 and the pressure roll 43 are the same as the specific examples of the intermediate transfer roll 22. The fixing roll 41 is provided with, for example, a heating member (not shown) such as a halogen lamp, and heats the toner image 18 by transferring heat generated from the heating member while contacting the toner image 18. As a temperature of heating, the range of 80 degreeC or more and 180 degrees C or less is mentioned, for example. On the other hand, the pressure roll 43 applies pressure to the fixing roll 41 as described above, and examples of the pressure include a range of 0.05 MPa to 10 MPa.

  In this embodiment, the fixing device 40 uses a method in which the fixing roll 41 directly contacts the toner image 18, but is not limited thereto, and a method for fixing the toner image 18 in a non-contact manner (for example, by light irradiation). A fixing device of a method, etc.). Among the fixing devices that directly contact the toner image 18, the fixing roll 41 and the pressure roll 43 are used in this embodiment, but the invention is not limited thereto. For example, a fixing belt is used instead of the fixing roll 41. The form may be sufficient and the form which uses a pressure belt instead of the pressure roll 43 may be sufficient.

The curable compound applying device 28 and the polymerization accelerator applying device 38 are configured to apply the curable compound 26 and the polymerization accelerator 36 to the toner image 18 in a non-contact manner, respectively. Specifically, for example, a device that applies the curable compound 26 or the polymerization accelerator 36 to the toner image 18 by a spray method or an ink jet method may be used.
Further, the curable compound applying device 28 and the polymerization accelerator applying device 38 are not limited to the above-described forms, and may be applied in contact with the toner image 18. As a form to be applied in contact with the toner image 18, for example, an application member (for example, a roll-shaped member or a belt-shaped member) that applies the curable compound 26 or the polymerization accelerator 36 is provided. Examples include a form in which the toner image 18 is directly contacted (that is, a form in which the toner image 18 is indirectly applied through the applying member). In the form using the applying member, for example, a cleaning means for removing the curable compound 26 or the polymerization accelerator 36 attached to the surface of the applying member may be provided separately.
In addition, from the viewpoint of suppressing image quality defects due to deterioration or the like of the applying member, a non-contact form is preferable to a form using the applying member. In other words, it is better to apply the curable compound 26 or the polymerization accelerator 36 directly to the toner image 18 or the fixed image 32 in a non-contact manner.
Details of the liquid developer 16, the curable compound 26, and the polymerization accelerator 36 will be described later.

Next, the operation of the image forming apparatus 100 will be briefly described.
The photoreceptor 10 is driven by, for example, a driving device (not shown) and rotated in the arrow B direction, and the intermediate transfer roll 22 is rotated in the arrow C direction accordingly.
First, the surface of the photoconductor 10 is charged by, for example, a non-contact charging device 12. Thereafter, the exposure device 14 performs exposure while scanning the side surface of the photoconductor 10 based on image data obtained from an information device (not shown), thereby forming an electrostatic latent image on the surface of the photoconductor 10.

  Next, the latent image formed on the surface of the photoconductor 10 is developed with the liquid developer 16 accommodated in the developing device 20 to form a toner image 18. Specifically, for example, the liquid developer 16 stored in the developer storage container 20B is stirred by a stirring member (not shown), and the toner particles 16A are dispersed in the solvent 16B. Further, for example, the developing roll 20A partially immersed in the liquid developer 16 rotates counterclockwise (arrow A direction), and the liquid developer 16 attached to the developing roll 20A is supplied by the regulating member 20C. In a controlled state, it is supplied to the latent image on the surface of the photoconductor 10, and the latent image is visualized to become a toner image 18.

The toner image 18 is conveyed by the photosensitive member 10 rotating in the clockwise direction (arrow B direction) and, for example, is transferred to the intermediate transfer roll 22 that rotates counterclockwise (arrow C direction) as the photosensitive member 10 rotates. Transcribed in contact.
Next, the toner image 18 conveyed in the direction of arrow C by the intermediate transfer roll 22 is conveyed to a position in contact with the recording medium 30 after the curable compound application device 28 applies the curable compound 26 in a non-contact manner. The On the other hand, the conveyance belt 42 on which the recording medium 30 is placed moves in the direction of arrow E, the recording medium 30 is conveyed to a position sandwiched between the intermediate transfer roll 22 and the transfer roll 34, and the intermediate transfer roll 22 is transferred to the recording medium 30. The upper toner image 18 is transferred.

  The toner image 18 transferred to the recording medium 30 is fixed on the recording medium 30 by the fixing device 40 after the polymerization accelerator is applied by the polymerization accelerator applying device 38. In the fixing device 40, the fixing roll 41 comes into contact with the toner image 18 on the recording medium 30, and the toner image 18 and the recording medium 30 are heated by a heating member (not shown) provided in the fixing roll 41. A fixed image 32 is formed by being fixed on the recording medium 30.

On the other hand, in the photoconductor 10 that has transferred the toner image 18 to the intermediate transfer roll 22, the untransferred toner 44 is conveyed to the contact position between the photoconductor 10 and the photoconductor cleaning member 24 and is collected by the photoconductor cleaning member 24. . Then, the latent image of the photoreceptor 10 from which the transfer residual toner 44 has been removed by the photoreceptor cleaning member 24 is erased by the charge eliminating device 46.
In the image forming apparatus 100 of the present embodiment, the above operation is repeated to continuously form images.

Here, when the liquid developer 16 containing the toner particles 16A and the solvent 16B is used, the toner image 18 and the fixed image 32 may also contain the solvent 16B.
However, the image forming apparatus 100 of this embodiment includes a curable compound applying device 28 and a polymerization accelerator applying device 38. The toner image 18 is provided with the curable compound 26 by the curable compound applying device 28 and the polymerization accelerator 36 by the polymerization accelerator applying device 38, whereby the curable compound 26 applied to the toner image 18. Is cured.

  Therefore, even if the solvent 16B remains in the toner image 18, the solvent 16B is cured together with the curable compound 26 in the fixed image 32. That is, in the image forming apparatus 100 of the present embodiment, a decrease in fixing strength due to the solvent 16B is suppressed as compared with an image forming apparatus that does not include the curable compound applying device 28.

Further, when the toner image 18 is fixed to the recording medium 30 by bringing the fixing roller 41 into contact with the toner image 18, the surface state of the fixing roller 41 is considered to affect the image quality of the fixed image 32.
However, in the image forming apparatus 100 of the present embodiment, the polymerization accelerator applying device 38 applies the polymerization accelerator 36 to the toner image 18 on the recording medium 30 directly and in a non-contact manner. Therefore, for example, a mode in which the polymerization accelerator 36 is applied to the fixing roll 41 and the fixing roll 41 is brought into contact with the toner image 18 (that is, a mode in which the polymerization accelerator 36 is indirectly applied to the toner image 18 through the fixing roll 41). In comparison with the above, deterioration of the surface of the fixing roll 41 caused by the polymerization accelerator 36 is suppressed, and unevenness in image density caused by deterioration or the like is suppressed.

  Further, since the image forming apparatus 100 according to the present embodiment includes the curable compound applying device 28, the liquid developer 16 may not contain the curable compound 26. For this reason, even when a drying oil is used as the curable compound 26, the viscosity of the liquid developer 16 is higher than when the liquid developer 16 containing the drying oil is used as the curable compound 26 without the curable compound applying device 28. Image density unevenness due to the rise is suppressed.

Here, the “drying oil” is an oil having an iodine value of 130 or more. Although details of specific examples and the like will be described later, it is a curable compound that is cured by chemically reacting with oxygen in the air. And the hardening reaction of drying oil is accelerated | stimulated with a heat | fever or a catalyst.
When drying oil is used as the curable compound 26 as in the present embodiment, the curable compound 26 and the polymerization accelerator 36 that is a catalyst are added to the toner image 18, whereby the curable compound 26 in the toner image 18 is formed. The curing reaction is accelerated, and a fixed image 32 having a high fixing strength is formed as compared with the case where no drying oil is used. Further, in this embodiment, since the toner image 18 is heated after the curable compound 26 is applied to the toner image 18, the curing reaction of the curable compound 26 in the toner image 18 is further accelerated. The

On the other hand, the curing reaction of the drying oil proceeds gradually without applying heat or a catalyst. That is, in the form in which the curable compound 26 is preliminarily contained in the liquid developer 16, by using a drying oil as the curable compound 26, the curing reaction of the drying oil gradually proceeds in the liquid developer 16, and the liquid developer. The viscosity of 16 may increase.
However, in the present embodiment, since the curable compound application device 28 is provided as described above, it is not necessary to include the curable compound 26 in the liquid developer 16, and even if dry oil is used as the curable compound 26, An increase in the viscosity of the liquid developer can be avoided. That is, in this embodiment, the type of the curable compound 26 to be used is not limited, and even when a drying oil is used as the curable compound 26, uneven image density due to an increase in the viscosity of the liquid developer is suppressed.

  In this embodiment, since the toner image 18 is heated by the fixing roll 41 after the curable compound 26 is applied to the toner image 18, the curing reaction of the curable compound 26 is accelerated by heating. Similarly, in this embodiment, since the toner image 18 is heated by the fixing roll 41 after the polymerization accelerator 36 is applied to the toner image 18, the curing reaction of the curable compound 26 in the polymerization accelerator 36 is performed. The promoting effect is improved by heating. Therefore, for example, a decrease in fixing strength is further suppressed as compared with a form in which the curable compound 26 is applied to the fixed image 32 or a form in which the polymerization accelerator 36 is applied to the fixed image 32.

  In the present embodiment, the configuration may be changed so that the curable compound 26 is applied to the fixed image 32. In this case, the toner image 18 provided with the curable compound 26 comes into contact with the fixing roll 41 and the curable compound 26 adheres to the surface of the fixing roll 41, whereby the surface of the fixing roll 41 is deteriorated or contaminated. Resulting image defects are suppressed.

  Further, in the present embodiment, the mode may be changed so that the polymerization accelerator 36 is added to the fixed image 32. In this case, the toner image 18 provided with the polymerization accelerator 36 comes into contact with the fixing roll 41 and the curable compound 26 adheres to the surface of the fixing roll 41, and the surface of the fixing roll 41 is deteriorated or contaminated. Image defects to be suppressed.

Second Embodiment
FIG. 2 is a schematic configuration diagram illustrating an image forming apparatus according to the second embodiment. The image forming apparatus according to the second embodiment is a color image forming apparatus in which four types of liquid developers are used and image forming units each configured for each type of liquid developer are arranged in parallel. In the image forming apparatus of the second embodiment, only one of the image forming units has a curable compound applying apparatus that directly applies a curable compound to the toner image on the intermediate transfer roll. The image forming apparatus according to the second embodiment includes a polymerization accelerator applying device that directly applies a polymerization accelerator to a toner image on a recording medium.

As shown in FIG. 2, the image forming apparatus 101 includes four image forming units 110Y, 110M, 110C, and 110BK corresponding to four colors (for example, yellow, magenta, cyan, and black) in the image forming apparatus 101. Are arranged in series in the horizontal direction.
Since the image forming unit 110Y has the same configuration as that of the image forming apparatus 100 of the first embodiment, description of the configuration in each image forming unit will be omitted. That is, the photoconductor 111Y, the charging device 112Y, the exposure device 114Y, the developing device 120Y, the intermediate transfer roll 122Y, the photoconductor cleaning member 124Y, the charge removal device 146Y, the transfer roll 134Y, and the curable compound applying device 128 in the image forming unit 110Y are as follows. , Respectively, in the image forming apparatus 100 of the first embodiment, the photoconductor 10, the charging device 12, the exposure device 14, the developing device 20, the intermediate transfer roll 22, the photoconductor cleaning member 24, the charge eliminating device 46, the transfer roll 34, and the curability. This is the same as the compound application device 28.
The image forming units 110M, 110C, and 110BK are the same as the image forming unit 110Y except that the type (color) of the liquid developer and the curable compound applying device 28 are not provided.

  The conveying belt passes between the intermediate transfer rollers 122Y, 122M, 122C, and 122BK in the four image forming units 110Y, 110M, 110C, and 110BK and the transfer rollers 134Y, 134M, 134C, and 134BK, respectively. 142 is provided. That is, the four image forming units 110 </ b> Y, 110 </ b> M, 110 </ b> C, and 110 </ b> BK are sequentially arranged along the transport belt 142 from the upstream side to the downstream side in the transport direction (arrow direction) of the transport belt 142.

  Further, a polymerization accelerator applying device 138 is disposed on the intermediate transfer roll 122BK side so as to face the conveyance belt 142 on the downstream side in the conveyance direction of the conveyance belt 142 with respect to the image forming unit 110BK. A fixing device 140 is disposed downstream of the polymerization accelerator applying device 138 in the conveying direction of the conveying belt 142. Specifically, the fixing belt 141 and the pressure roll 143 are used to fix the conveying belt 142. A fixing device 140 is arranged so as to be sandwiched.

Next, an image forming method using the image forming apparatus 101 shown in FIG. 2 will be described.
The toner image is formed in each image forming unit. First, in the image forming unit 110Y, a yellow toner image is formed by the same method as that of the image forming apparatus 100 of the first embodiment and transferred to the intermediate transfer roll 122Y. Is provided with a curable compound.
On the other hand, when the conveyance belt 142 carries the recording medium and moves in the conveyance direction, the recording medium moves from the upstream side in the conveyance direction to the downstream side. Then, when the recording medium passes between the intermediate transfer roll 122Y and the transfer roll 134Y in the image forming unit 110Y, the yellow toner image to which the curable compound is applied is transferred from the intermediate transfer roll 122Y to the recording medium. .

  In the image forming units 110M, 110C, and 110BK, magenta, cyan, and black toner images are formed in the same manner as the image forming unit 110Y, respectively, except that no curable compound is added to the toner images. Transferred to transfer rolls 122M, 122C, and 122BK. When the recording medium on which the yellow toner image is transferred passes between the intermediate transfer roll 122M and the transfer roll 134M in the image forming unit 110M, the magenta toner image is transferred from the intermediate transfer roll 122M to the recording medium. Subsequently, the cyan toner image and the black toner image are transferred to the recording medium from the intermediate transfer rolls 122C and 122BK, respectively. That is, for example, when an image of a color using yellow and magenta is formed, the magenta toner image is transferred onto the recording medium and superimposed on the yellow toner image to which the curable compound has been applied, so that the curability is increased. Yellow and magenta toner images containing the compound are obtained.

The recording medium to which the toner image has been transferred is further conveyed in the conveying direction by the conveying belt 142, and the polymerization accelerator is applied to the toner image on the recording medium at the position where the polymerization accelerator applying device 138 is disposed. Thereafter, the recording medium in which the polymerization accelerator is applied to the toner image is further conveyed in the conveying direction, and the fixing roll 141 of the fixing device 140 directly contacts the toner image to apply heat and pressure, whereby the toner image is recorded on the recording medium. And a color fixed image is formed.
As described above, a color image is formed by the image forming apparatus 101.

The image forming apparatus 101 of this embodiment includes a curable compound applying device 128 that applies a curable compound to a toner image, and a polymerization accelerator applying device 138 that applies a polymerization accelerator to the toner image. Specifically, a curable compound is applied to the toner image on the intermediate transfer roll 122Y of the image forming unit 110Y, and after the toner images of all colors are transferred to the recording medium, polymerization is promoted to a toner image containing the curable compound. An agent is applied.
Therefore, for example, even when a magenta toner image not containing a curable compound is superimposed on a yellow toner image transferred onto a recording medium, the curing reaction of the curable compound imparted to the yellow toner image is performed. Thus, not only the liquid developer solvent contained in the yellow toner image but also the liquid developer solvent contained in the magenta toner image are cured together.
Therefore, in this embodiment, an image is formed using a liquid developer, and a yellow toner image is formed over the entire image portion on the recording medium even if the solvent of the liquid developer remains in the fixed image. A reduction in fixing strength due to the solvent of the liquid developer is suppressed.

Further, the image forming apparatus 101 of the present embodiment applies the polymerization accelerator directly to the toner image on the recording medium from the polymerization accelerator applying apparatus 138 in a non-contact manner, similarly to the image forming apparatus 100 of the above embodiment. is there.
Therefore, even when the fixing roll 141 is brought into direct contact with the toner image and the toner image is fixed on the recording medium, deterioration on the surface of the fixing roll 141 and adhesion of a cured product due to the polymerization accelerator are suppressed. Image defects caused by deterioration or the like on the surface of the film are suppressed.
Further, the image forming apparatus 101 of the present embodiment also includes the curable compound applying device 128 as in the case of the image forming apparatus 100 of the above embodiment. Therefore, the liquid developer may not contain the curable compound. . Therefore, even when drying oil is used as the curable compound, image density unevenness due to an increase in the viscosity of the liquid developer is suppressed as compared with the conventional form in which the liquid developer contains the curable compound.

In this embodiment, only the image forming unit 110Y is provided with the curable compound applying device 128. However, the present invention is not limited to this, and the curable compound applying device 128 may be provided in another image forming unit. The image forming unit may be provided in a plurality of image forming units. In addition, a form in which the curable compound applying device 128 is provided in a place other than the image forming unit (for example, a form in which the curable compound is applied to the toner image on the recording medium, or a form in which the curable compound is applied to the fixed image). )
Further, the polymerization accelerator applying device 138 is not limited to the form in which the polymerization accelerator is applied after all the toner images have been transferred onto the recording medium, and between the image forming units (that is, some of the toner images are transferred). The polymerization accelerator may be applied to the toner image on the recording medium before (a), or the polymerization accelerator may be applied to the toner image in the image forming unit (for example, on the intermediate transfer roll 122BK).

  In this embodiment, the yellow, magenta, cyan, and black toner images are sequentially formed on the recording medium. However, the present invention is not limited to this, and the toner images may be formed in different orders. The type and number of liquid developers are also selected as necessary, and are not limited to the above forms.

<Third Embodiment>
FIG. 3 is a schematic configuration diagram illustrating an image forming apparatus according to the third embodiment. As in the second embodiment, the image forming apparatus according to the third embodiment uses four types of liquid developer, and forms a color image in which image forming units configured for each type of liquid developer are arranged in parallel. Device. However, in this embodiment, in each image forming unit, the toner image formed on the surface of the photoreceptor is directly transferred to the recording medium without using the intermediate transfer roll (that is, the intermediate transfer member is not used). Form).
The image forming apparatus according to the third embodiment includes a curable compound applying device that applies a curable compound to the toner image on the recording medium after all the toner images have been transferred to the recording medium, and after being fixed. A polymerization accelerator applying device for applying a polymerization accelerator to the fixed image.

As in the image forming apparatus 101 of the second embodiment, the image forming apparatus 102 shown in FIG. 3 includes four image forming units 210Y, 210M, 210C, and 210BK in series in the horizontal direction in the image forming apparatus 102. Has been placed.
The image forming units 210Y, 210M, 210C, and 210BK have the image forming units 110Y, 110M, 110C, and 210C in the image forming apparatus 101 according to the second embodiment except that the image forming units 210Y, 210M, 210C, and 210BK do not include the intermediate transfer roll and the curable compound application unit. Since it is the same structure as 110BK and description is abbreviate | omitted. Specifically, for example, the photosensitive member 211Y, the charging device 212Y, the exposure device 214Y, the developing device 220Y, the photosensitive member cleaning member 224Y, the static eliminating device 246Y, and the transfer roll 234Y in the image forming unit 210Y are respectively in the second embodiment. Similar to the photoconductor 111Y, the charging device 112Y, the exposure device 114Y, the developing device 120Y, the photoconductor cleaning member 124Y, the charge removal device 146Y, and the transfer roll 134Y in the image forming unit 110Y, and the image forming units 210M, 210C, and 210BK. Is the same.

The conveyor belt 242 is provided so as to pass between the photoreceptors 211Y, 211M, 211C, and 211BK and the transfer rolls 234Y, 234M, 234C, and 234BK, respectively.
Further, on the downstream side of the image forming unit 210BK in the conveying direction of the conveying belt 242, a curable compound applying unit 228, a fixing roll 241, and a polymerization accelerator applying device 238 are sequentially arranged on the photosensitive member 211BK side. . Further, a pressure roll 243 is disposed on the opposite side of the conveyance belt 242 to the fixing roll 241, and the fixing roll 241 and the pressure roll 243 constitute a fixing device 240.

Next, an image forming method using the image forming apparatus 102 shown in FIG. 3 will be described.
Similar to the image forming apparatus 101 of the second embodiment, the toner image is formed in each image forming unit. Specifically, in the image forming units 210Y, 210M, 210C, and 210BK, yellow, magenta, cyan, and black toner images are formed on the photoreceptors 211Y, 211M, 211C, and 211BK, respectively.
Then, the recording medium moves on the conveying belt 242 and moves in the conveying direction. After the toner images are sequentially transferred from the photoconductors 211Y, 211M, 211C, and 211BK to the recording medium, the curable compound applying device 228 converts the toner images into toner images. A curable compound is provided.
Thereafter, the fixing roll 241 of the fixing device 240 directly contacts the toner image on the recording medium to apply heat and pressure to form a fixed image, and the polymerization accelerator is applied to the fixed image by the polymerization accelerator applying device 238. .
As described above, a color image is formed by the image forming apparatus 102.

  The image forming apparatus 102 according to this embodiment includes a curable compound applying device 228 that applies a curable compound to a toner image, and a polymerization accelerator applying device 238 that applies a polymerization accelerator to a fixed image. Therefore, even if the image is formed using a liquid developer, and the solvent of the liquid developer remains in the fixed image, the fixing strength due to the solvent of the liquid developer is suppressed by the curing of the curable compound. The

Further, the image forming apparatus 102 according to the present embodiment is a form in which the polymerization accelerator is applied directly and non-contactly from the polymerization accelerator applying device 238 to the fixed image formed by the fixing device 240. Therefore, even when the fixing roll 241 is brought into direct contact with the toner image and the toner image is fixed on the recording medium, the polymerization accelerator does not adhere to the fixing roll 241, and is caused by the polymerization accelerator on the surface of the fixing roll 241. Image defects due to deterioration or the like are suppressed.
In addition, since the image forming apparatus 102 according to the present embodiment includes the curable compound applying apparatus 228 as in the case of the image forming apparatus 100 according to the above-described embodiment, the liquid developer may not include the curable compound. Therefore, even when drying oil is used as the curable compound, image density unevenness due to an increase in the viscosity of the liquid developer is suppressed as compared with the conventional form in which the liquid developer contains the curable compound.
Other forms that can be used are the same as those in the above embodiment, and thus description thereof is omitted.

<Liquid developer>
Hereinafter, the liquid developer will be described.
The liquid developer contains toner particles and a solvent as described above, and may contain other components as necessary. In the present embodiment, as described above, since a curable compound providing unit is separately provided, it is not necessary to add a curable compound to the liquid developer. From the viewpoint of suppressing an increase in the viscosity of the liquid developer, it is preferable that the liquid developer does not contain a curable compound, and even if it is contained, it is 0.1% by mass or less with respect to the entire liquid developer. It is good that it is.

As the solvent used in the liquid developer is not particularly limited, high electrical resistivity 1.0 ¹² or more solvents for that it is necessary to suitably disperse the resin and the electrostatic latent image holding are preferred, for example, Aliphatic hydrocarbons, silicone solvents, fluorine solvents and the like can be mentioned.
More specifically, examples of the solvent include fatty acid saturated hydrocarbons, branched chain ethers, branched chain ester oils, white oil (liquid paraffin), mineral oil, spindle oil, and poly α-olefin oil systems. And petroleum solvents such as Isopar H, L and M manufactured by Exxon, silicone oils such as dimethylpolysiloxane, and fluorine oil dispersion media such as perfluoropolyether.
The solvent may be selected according to the curable compound to be used (for example, a solvent having a high affinity with the curable compound is selected).

The toner particles include at least a binder resin and, if necessary, components such as a colorant and a release agent.
Examples of the binder resin include polyester, polyurethane, epoxy resin, silicone resin, polyamide, polystyrene, styrene-acrylic copolymer, and styrene-butadiene copolymer, but are not particularly limited. It is selected according to the required characteristics.
Examples of the colorant include carbon black, inorganic pigments, azo pigments, copper phthalocyanine, phthalocyanine pigments, and condensed polycyclic pigments, but are not particularly limited, and are selected according to the color of the image to be formed. .
Examples of the release agent include, but are not limited to, hydrocarbon waxes, natural waxes, synthetic or mineral / petroleum waxes, ester waxes, and the like.
The toner particles may contain, for example, an ultraviolet curable resin in addition to the above components. When image formation is performed with a liquid developer using toner particles containing an ultraviolet curable resin, for example, the fixed image may be irradiated with ultraviolet light to form a fixed image with higher fixing strength.

<Curable compound>
Hereinafter, the curable compound will be described.
Examples of the curable compound include dry oil as described above.
Specific examples of the drying oil include an ester compound having at least one carbon-carbon double bond in the molecule, the number of carbon atoms is 3 to 60, and the double bond is at least One or more unsaturated acids (eg acrylic acid, butenoic acid, hexenoic acid, octenoic acid, dodecenoic acid, ricinoleic acid, oleic acid, linoleic acid, linolenic acid, eleostearic acid, etc.) and at least two hydroxyl groups Ester compounds with polyhydric alcohols (eg, alkyl diols such as hexanediol, glycols such as ethylene glycol and propylene glycol, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, etc.), the above unsaturated acids and saturated Esterification of a mixture of acids with the polyhydric alcohol Those in which synthetic fatty oils or natural fatty oil, and the like.

Representative compounds of natural fatty oils include, for example, cinnabar oil, linseed oil, soybean oil, safflower oil, and kili oil. In addition, dehydrated linseed stand oil and castor oil obtained by polymerizing linseed oil are used. Dehydrated castor oil, fatty oil (eg, drill oil) modified with maleic anhydride, and styrenated oil obtained by copolymerizing the drying oil and styrene (or vinyltoluene) Synthetic drying oils such as (or vinyl toluated oil).
Examples of the curable compound other than the drying oil include a photocurable compound. Specifically, for example, a radically polymerizable compound having a carbon-carbon double bond such as polyethylene glycol dimethacrylate or polypropylene glycol dimethacrylate. Examples thereof include acrylate compounds that are compounds, and cation polymerizable compounds typified by epoxidized soybean oil, epoxidized linseed oil, and oxetane compounds.

The amount of the curable compound added to the toner image or the fixed image is not particularly limited, and examples thereof include a range of 0.1 g / m ^{2 to} 10 g / m ^{2, and} a range of 0.1 g / m ^{2 to} 3 g / m. The range may be ² or less.
For example, the curable compound may be applied to the toner image or the fixed image as it is, or may be applied to the toner image or the fixed image by dispersing an ultraviolet curable resin in the curable compound.

<Polymerization accelerator>
Hereinafter, the polymerization accelerator will be described.
The polymerization accelerator is selected according to the curable compound to be used. Examples of the thermal polymerization initiator used for the thermally polymerizable compound such as drying oil include, for example, a liquid or pasty metal dryer (metal drying agent). ) Octylate metal or naphthenate metal. The metal of the octylic acid metal and naphthenic acid metal is not particularly limited, and examples thereof include cobalt, manganese, barium, zirconium, calcium, iron, and potassium. Further, the amount of metal contained in the metal octylate and metal naphthenate is not particularly limited. For example, the range is 1% by mass to 30% by mass with respect to the acid component (that is, octylic acid or naphthenic acid). Can be mentioned.
Although it does not specifically limit as addition amount of a polymerization accelerator, For example, when using dry oil as a sclerosing | hardenable compound, it is 0.01 mass part or more and 3 mass parts or less, for example with respect to 100 mass parts of the double bond of drying oil. The range may be mentioned, and may be a range of 0.1 parts by mass or more and 2 parts by mass or less.

In addition to the thermal polymerization accelerator, examples of the polymerization accelerator include a photopolymerization accelerator (that is, a polymerization accelerator that accelerates curing of the photocurable compound by light irradiation). Specific examples of the photopolymerization accelerator include, for example, benzophenone, benzoin isobutyl ether, benzoin ethyl ether, methyl benzoylbenzoate, benzyl, 4-chlorobenzophenone, 4-phenylbenzophenone, 4p-trithiobenzophenone, and 2-hydroxy. -2,2-dimethylacetophenone, 2,2-diethoxyacetophenone, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, Lucirin TPO and Lucin TPO-L from BASF, Irgacure 1850 from Ciba Specialty Chemicals, Irga Cure 1700, Irgacure 819, etc. are mentioned.
Among the photopolymerization initiators such as 2,4,6-trimethylbenzoyl-phenylethoxy phosphine oxide containing phosphorus in its structure has a strong function to accelerate the curing of the photocurable compound, preferably for no yellowing is there.
Also, initiators such as BASF's Lucillin TPO and Lucillin TPO-L, Ciba Specialty Chemicals Irgacure 1850, Irgacure 1700, Irgacure 819, and thioxanthones such as 2,4-diethylthioxanthone 2-chlorothioxanthone by combining a polymerization initiator, and further enhances the function to accelerate the curing of the photocurable compound.

When a hydrogen abstraction type benzophenone photopolymerization initiator is used as a polymerization accelerator, an amine sensitizer may be used in combination. As a result, the amine sensitizer supplies hydrogen to the benzophenone photopolymerization initiator to accelerate the hydrogen abstraction action, and the reaction inhibition of the hydrogen abstraction action due to oxygen in the air is suppressed. The hardening accelerating action increases.
The addition amount of the amine sensitizer is 1 to 15 parts by mass, desirably 3 to 8 parts by mass with respect to 100 parts by mass of the benzophenone photopolymerization initiator.
Examples of the amine sensitizer include triethanolamine, triisopropanolamine, 4,4-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, ethyl 4-dimethylaminobenzoate, isoacyl 4-dimethylaminobenzoate, and the like. Is mentioned.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention.

[Example 1]
<Preparation of liquid developer>
Cyan pigment C.I. to 60 parts by mass of a polyester resin (manufactured by Kao Corporation). I. 40 parts by mass of Pigment Blue 15: 3 (manufactured by Clariant Co., Ltd.) was added and kneaded with a pressure kneader. The kneaded product was coarsely pulverized to prepare a cyan pigment master batch.

Next, a mixture having the following composition was dissolved and dispersed in a ball mill for 24 hours.
-Polyester resin (product of Kao Corporation): 60 parts by mass-Cyan pigment master batch: 25 parts by mass-Polyester polyol (DIC product): 5 parts by mass-Ethyl acetate: 100 parts by mass

  On the other hand, 20 parts by mass of calcium carbonate (manufactured by Maruo Calcium Co., Ltd., Luminous) as a dispersion stabilizer is added to an aqueous solution in which 20 parts by mass of sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved in 135 parts by mass of ion-exchanged water. In addition, it was dispersed for 24 hours with a ball mill to obtain a dispersion medium. 100 parts by mass of the mixture dispersed in 170 parts by mass of this dispersion medium was added, and the mixture was emulsified for 1 minute at 8000 rpm 24000 rpm in an emulsification apparatus (HI-FLEX HOMOGENIZER Ultra Turrax T-25 manufactured by SMT Co., Ltd.). A turbid liquid was obtained.

  Put the above suspension into a separable flask equipped with a stirrer, thermometer, cooling pipe and nitrogen introduction pipe, and stir at 60 ° C for 3 hours while introducing nitrogen from the nitrogen introduction pipe to remove ethyl acetate. did. Thereafter, the mixture was cooled, a 10% aqueous hydrochloric acid solution was added to the reaction solution to decompose calcium carbonate, and solid-liquid separation was performed by centrifugation. The obtained particles were washed three times with 1 L of ion exchange water, and then the obtained particles were vacuum dried at 40 ° C. to obtain cyan toner particles.

  A mixture of 35 parts by mass of dried cyan toner particles and 103 parts by mass of white oil (Moleco White P-40 manufactured by Matsumura Oil Co., Ltd.) and 1.5 parts by mass of Solsperse 13240 (manufactured by Nihon Lubrizol). Then, it was pulverized by a ball mill to obtain a cyan liquid developer having an average particle size of 1.0 μm.

  Further, magenta toner particles, yellow toner particles, and black toner particles were obtained in the same manner as the cyan toner particles, except that a magenta pigment, a yellow pigment, and a black pigment were used instead of the cyan pigment. Further, in the same manner as the cyan liquid developer, except that magenta toner particles, yellow toner particles, and black toner particles are used instead of cyan toner particles, magenta liquid developer, yellow liquid developer, and black liquid, respectively. A developer was obtained.

<Fixed image formation>
Using the cyan liquid developer among the obtained liquid developers, a fixed image was formed by the image forming apparatus 100 (FIG. 1) of the first embodiment. As the recording medium 30, Fuji Xerox Office Supply (J paper) was used, and an image was formed so that the image density was 4.0 g / m ² .
Further, linseed oil is used as the curable compound 26, and the curable compound 26 is applied as it is to the toner image 18 on the intermediate transfer roll 22 by a non-contact (spray type) curable compound applying device 28, thereby curable compound. 26 layers were applied so as to be 2 μm.
Further, cobalt naphthenate is used as the polymerization accelerator 36, and the polymerization accelerator 36 is directly applied to the toner image 18 on the recording medium 30 by a non-contact (spray type) polymerization accelerator applying device 38. The layer was applied so as to be 1 μm.

In the fixing device 40, the fixing roll 41 was brought into direct contact with the toner image 18, and the toner image 18 provided with the curable compound 26 and the polymerization accelerator 36 was fixed on the recording medium 30. The fixing conditions were heating temperature: 180 ° C., surface pressure: 3.3 kgf / cm ² , and time for passing through a region where the fixing roll 41 and the pressure roll 43 are in contact: 30 msec.

<Evaluation>
(Evaluation of viscosity change in liquid developer)
Viscosity change was evaluated using the obtained liquid developer. Specifically, 5 g of liquid developer was placed in a glass sample bottle (10 ml) and sealed. This was stored still for 24 hours in an environment of temperature 50 ° C. and humidity 30% RH. The viscosity (Va) of the liquid developer before storage and the viscosity (Vb) of the liquid developer after storage were measured with a rotary viscometer Bismetron VGA-L type (manufactured by Shibaura System Co., Ltd.). ) = (Vb−Va) × 100 / Va and evaluated. The results are shown in Table 1.

(Evaluation of fixing strength in fixed images)
The fixing strength of the fixed image after the ultraviolet irradiation was evaluated by a tape peeling test method. Specifically, an adhesive tape (manufactured by Nichiban Co., Ltd .: cellophane tape) is applied to the fixed image with a width of 18 mm, a cylindrical block is rolled on the adhesive tape in the circumferential direction, and the tape is imaged at a linear pressure of 300 g / cm. Then, the tape was peeled off, and the optical density ratio of the front and back images was defined as the fixing rate. Specifically, the fixing rate is obtained from the optical density (OD ₁ ) before tape application and the optical density (OD ₂ ) after tape peeling using the following equation. The optical density was measured using a spectrocolorimeter (X-rite 938, manufactured by X-rite). The evaluation criteria are as follows. The results are shown in Table 2.
Formula: Fixing rate (%) = OD ₂ × 100 / OD ₁

-Evaluation criteria for fixing rate-
○: Fixing rate of 90% or more Δ: Fixing rate of 80% or more and less than 90% ×: Fixing rate of less than 80%

(Evaluation of uneven image density in fixed images)
The fixed image after the ultraviolet irradiation was visually observed to evaluate unevenness in image density. The evaluation criteria are as follows. The results are shown in Table 2.

-Evaluation criteria for uneven image density-
○: Image density unevenness was not confirmed at all.
Δ: Image density unevenness was slightly confirmed, but was within an allowable range.
X: Image density unevenness was remarkably confirmed and exceeded the allowable range.

[Example 2]
<Preparation of liquid developer>
A cyan liquid developer 2 was obtained in the same manner as in Example 1 except that a mixture having the following composition was used as the mixture dispersed by the ball mill.
Polyester resin (product of Kao Corporation): 60 parts by mass Cyan pigment masterbatch: 25 parts by mass Polyester polyol (DIC product): 5 parts by mass Ethyl acetate: 100 parts by mass Polyethylene glycol dimethacrylate (Photocurable resin, manufactured by Aldrich): 10 parts by mass

<Preparation of photopolymerization accelerator solution>
5 parts by mass of methyl benzoylbenzoate and 5 parts by mass of isoamyl 4-dimethylaminobenzoate were dissolved in 90 parts by mass of a solvent (orthoxylene (manufactured by Wako Pure Chemical Industries, Ltd.)) to prepare a photopolymerization accelerator solution. .

<Formation and evaluation of fixed images>
A fixed image was formed in the same manner as in Example 1 except that the cyan liquid developer 2 was used as the liquid developer.
Next, the obtained photopolymerization accelerator solution was applied to the fixed image 32 formed by the fixing device 40 in a non-contact manner (spray method). The photopolymerization accelerator solution was applied to a thickness of 3 μm.
Using a UV lamp (LC8) manufactured by Hamamatsu Photonics, the fixed image 32 to which the photopolymerization accelerator solution has been applied is irradiated with ultraviolet rays so that the integrated light quantity becomes 120 mJ / cm ² at an illuminance of 1.0 W / cm ^2. did.
In the same manner as in Example 1, the fixing strength and the image density unevenness were evaluated. The results are shown in Table 2.

[Example 3]
A fixed image was formed and fixed in the same manner as in Example 1 except that polyethylene glycol dimethacrylate (Aldrich), which is a curable compound other than drying oil, was used as the curable compound 26 instead of linseed oil. Evaluation of strength and unevenness of image density were performed. The results are shown in Table 2.

[Example 4]
Similar to Example 1, except that the polymerization accelerator applying device 38 of the image forming apparatus 100 (FIG. 1) of the first embodiment is modified to apply the polymerization accelerator 36 to the fixing roll 41 of the fixing device 40. Then, a fixed image was formed, and the fixing strength and the image density unevenness were evaluated. The results are shown in Table 2.

[Comparative Example 1]
A fixed image is formed in the same manner as in Example 1 except that the curable compound applying device 28 of the image forming apparatus 100 (FIG. 1) of the first embodiment is removed, and evaluation of fixing strength and unevenness of image density are performed. Evaluation was performed. The results are shown in Table 2.

[Comparative Example 2]
<Manufacture of liquid developer>
80 parts by mass of epoxy resin (Epicoat 1004, manufactured by Japan Epoxy Resin Co., Ltd.) and 20 parts by mass of cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3) are mixed by a 20 L type Henschel mixer to obtain a mixture. Obtained.
Next, the mixture was kneaded using a biaxial kneading extruder, and the kneaded product extruded from the extrusion port of the biaxial kneading extruder was cooled by a cooler. The cooled kneaded product was pulverized to prepare a comparative cyan pigment master batch.

Next, a mixture having the following composition was dissolved and dispersed in a ball mill for 200 hours.
-Comparative cyan pigment master batch: 100 parts by mass-Methyl oleate: 100 parts by mass-Solsperse 11200 (manufactured by Nippon Lubrizol Corporation): 10 parts by mass-Manganese naphthenate: 1.4 parts by mass

  Next, 100 parts by mass of the dispersed mixture and 400 parts by mass of safflower oil (Nisshin Oilio Co., Ltd.) were mixed to obtain a comparative cyan liquid developer 1.

<Fixed image formation>
A fixed image was formed in the same manner as in Comparative Example 1 except that the obtained comparative cyan liquid developer 1 was used instead of the cyan liquid developer.
<Evaluation>
The obtained comparative cyan liquid developer 1 was evaluated for changes in viscosity in the same manner as in Example 1. The results are shown in Table 1.
The obtained fixed image was evaluated for fixing strength and uneven image density in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 3]
<Manufacture of liquid developer>
Cyan toner particles were produced in the same manner as in Example 1.
35 parts by weight of dried cyan toner particles, 103 parts by weight of white oil (Moleco White P-40 manufactured by Matsumura Oil Co., Ltd.), 1.5 parts by weight of Solsperse 13240 (manufactured by Nihon Lubrizol), and 10 parts of linseed oil Part of the mixture was finely pulverized with a ball mill to obtain a comparative cyan liquid developer 2 having an average particle size of 1.0 μm.

<Fixed image formation>
A fixed image was formed in the same manner as in Comparative Example 1 except that the obtained comparative cyan liquid developer 2 was used instead of the cyan liquid developer.
<Evaluation>
The resulting comparative cyan liquid developer 2 was evaluated for changes in viscosity in the same manner as in Example 1. The results are shown in Table 1.
The obtained fixed image was evaluated for fixing strength and uneven image density in the same manner as in Example 1. The results are shown in Table 2.

  From the above results, it can be seen that in Example, the fixing strength is higher than that in Comparative Example 1, and the image density unevenness is suppressed as compared with Comparative Example 2 and Comparative Example 3. Further, it can be seen that the image density unevenness is suppressed in the first embodiment as compared with the fourth embodiment.

10, 111Y, 111M, 111C, 111BK, 211Y, 211M, 211C, 211BK Photosensitive member (latent image holding member)
12, 112Y, 112M, 112C, 112BK, 212Y, 212M, 212C, 212BK Charging device (latent image forming means)
14, 114Y, 114M, 114C, 114BK, 214Y, 214M, 214C, 214BK Exposure apparatus (latent image forming means)
16 Liquid developer 16A Toner particle 16B Solvent 18 Toner image 20, 120Y, 120M, 120C, 120BK, 220Y, 220M, 220C, 220BK Developer (Developing means)
22, 122Y, 122M, 122C, 122BK Intermediate transfer roll 26 Curable compound 28, 128, 228 Curable compound application device (curable compound application means)
30 recording medium 32 fixed image 34, 134Y, 134M, 134C, 134BK, 234Y, 234M, 234C, 234BK transfer roll 36 polymerization accelerator 38, 138, 238 polymerization accelerator applying device (polymerization accelerator applying means)
40, 140, 240 Fixing device (fixing means)
41, 141, 241 Fixing roll (fixing member)
100, 101, 102 Image forming apparatus 110Y, 110M, 110C, 110BK, 210Y, 210M, 210C, 210BK Image forming unit

Claims (3)

A latent image carrier,
Latent image forming means for forming a latent image on the surface of the latent image holder;
Developing means for developing the latent image formed on the surface of the latent image holding member with a liquid developer containing toner particles and a solvent to form a toner image;
Transfer means for transferring the toner image formed on the surface of the latent image holding member onto a recording medium;
Fixing means for fixing the toner image transferred to the recording medium to the recording medium to form a fixed image;
A curable compound applying means for applying a curable compound to at least one of the toner image and the fixed image;
An image forming apparatus comprising: a polymerization accelerator applying unit that applies a polymerization accelerator to at least one of the toner image and the fixed image.   2. The polymerization accelerator applying means according to claim 1, wherein the polymerization accelerator applying means is a means for applying a polymerization accelerator directly and non-contact to at least one of the toner image and the fixed image transferred onto the recording medium. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the curable compound is a dry oil.

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