JP6217420B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an image forming apparatus and an image forming method.

  Ink jet ink generally tends to bleed when attached to a recording medium. For example, when ink-jet ink adheres to plain paper, the ink-jet ink diffuses along the fiber lines of pulp, and bleeding tends to occur. When ink jet ink bleeding occurs, the image density decreases and the edge of the image is blurred, which causes image deterioration.

Patent Document 1 discloses an oil-based inkjet printing method in which printing is performed by applying a pretreatment liquid to a print medium and then discharging an oil-based ink containing at least a pigment and a solvent onto the print medium. At this time, the pretreatment liquid includes at least inorganic particles having an average particle diameter of 1 μm or more and 20 μm or less and a solvent, and the solubility parameter (SP value) of the solvent of the pretreatment liquid and the solubility parameter (SP value) of the solvent of the oil-based ink. ) Is 1.0 (cal / cm ³ ) ^1/2 or more.

  However, since the pretreatment liquid contains inorganic particles, the cost increases, and when the printing medium is a transparent film, there is a problem that the transparency of the printing medium is lowered.

  In view of the above-described problems of the related art, an embodiment of the present invention provides an image forming apparatus and an image forming method capable of suppressing the occurrence of bleeding without using a pretreatment liquid containing inorganic particles. Objective.

  According to one embodiment of the present invention, in an image forming apparatus, an intermediate transfer member, a coating unit that applies a first solvent to the intermediate transfer member, and a first ink that is applied to the intermediate transfer member by ejecting inkjet ink. And a transfer means for transferring the ink-jet ink attached to the first solvent to a recording medium. The ink-jet ink includes a second solvent, a resin, and a coloring material, The second solvent is soluble in the first solvent, and the resin is insoluble in the first solvent, soluble in the second solvent, and attached to the first solvent. It further has a liquid removal mechanism for removing at least a part of the first solvent applied to the intermediate transfer member and the second solvent adhering to the first solvent before transferring the ink to the recording medium.

  In one embodiment of the present invention, in the image forming method, a step of applying a first solvent to the intermediate transfer member, and a step of discharging an inkjet ink to adhere to the first solvent applied to the intermediate transfer member; And transferring the ink-jet ink attached to the first solvent to a recording medium, wherein the ink-jet ink contains a second solvent, a resin and a coloring material, and the second solvent is the first solvent The resin is soluble in the solvent, the resin is insoluble in the first solvent, the resin is soluble in the second solvent, and before the inkjet ink attached to the first solvent is transferred to the recording medium And a step of removing at least a part of the first solvent applied to the intermediate transfer member and the second solvent adhering to the first solvent.

  According to one embodiment of the present invention, it is possible to provide an image forming method, an image forming apparatus, and an image forming method capable of suppressing the occurrence of bleeding without using a pretreatment liquid containing inorganic particles.

It is a schematic diagram showing a first embodiment of the image forming method of the present invention. It is a conceptual diagram which shows an example of the method of selecting a 1st solvent, a 2nd solvent, and resin. It is a conceptual diagram which shows the other example of the method of selecting a 1st solvent, a 2nd solvent, and resin. It is a schematic diagram which shows the liquid absorption member used with the image forming method of FIG. It is a schematic diagram which shows the modification of the liquid absorption member of FIG. It is a schematic diagram which shows the modification of the liquid absorption member of FIG. It is a schematic diagram which shows the liquid non-absorbing member used in 2nd embodiment of the image forming method of this invention. 1 is a schematic diagram showing a first embodiment of an image forming apparatus of the present invention. It is a schematic diagram which shows 2nd embodiment of the image forming apparatus of this invention. It is a schematic diagram which shows 3rd embodiment of the image forming apparatus of this invention.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows a first embodiment of the image forming method of the present invention.

  First, the first solvent S is applied to the entire surface of a sheet-like elastic member E as an intermediate transfer member (see FIG. 1A).

  Next, the inkjet ink I is discharged and adhered to the first solvent S applied to the elastic member E (see FIG. 1B). At this time, the inkjet ink I includes a second solvent, a resin, and a coloring material, the second solvent is soluble in the first solvent S, and the resin is insoluble in the first solvent S, It is soluble in the second solvent. For this reason, the first solvent S can precipitate the resin when the inkjet ink I is dropped.

  As soon as the inkjet ink I adheres to the first solvent S, the second solvent in the inkjet ink I diffuses into the first solvent S, and the mixed solvent is a mixture of the first solvent and the second solvent. As a result, the inkjet ink I ′ having increased viscosity is produced (see FIG. 1C). At that time, since the resin in the inkjet ink I is not dissolved in the first solvent S, the resin and the coloring material are difficult to diffuse into the first solvent S. As a result, the resin and color material in the inkjet ink I ′ having increased viscosity are less likely to diffuse, and the occurrence of bleeding can be suppressed.

  Further, the ink-jet ink I ′ having increased viscosity is transferred to the paper P (see FIG. 1D). The ink-jet ink I ′ having an increased viscosity can improve transferability because the mixed solvent S ′ with the elastic member E serves as a shielding layer. At this time, the ink jet ink I ′ having the increased viscosity transferred to the paper P is less likely to diffuse the resin and the color material, so that the occurrence of bleeding can be further suppressed. Thereafter, the mixed solvent S ′ remaining in the ink-jet ink I ′ having increased viscosity transferred to the paper P evaporates or diffuses into the paper P, so that the ink-jet ink I ′ having increased viscosity is solidified to form the paper P. To settle. As a result, it is possible to form a sharp image with high image density. In addition, the configuration of the image forming apparatus can be simplified.

  The viscosity of the first solvent S at 25 ° C. is usually 30 mPa · s or less. As a result, the first solvent S can be applied so that the moving speed of the elastic member E is at a high speed of 500 mm / s or more and the unevenness of the thickness of the liquid film is uniform with an average thickness of ± 30% or less. .

  The viscosity of the inkjet ink I and the second solvent at 25 ° C. is usually 30 mPa · s or less. Thereby, the inkjet ink I can be discharged using an inkjet head.

  For this reason, the diffusion rate at which the second solvent diffuses into the first solvent S is sufficiently larger than the diffusion rate at which the resin and the coloring material diffuse into the first solvent S. As a result, the second solvent diffuses into the first solvent S before the resin and the color material diffuse into the first solvent S in the state of FIG. A region with increased viscosity is formed in the vicinity of the contact surface with the solvent S, and diffusion of the resin and the coloring material into the first solvent S can be suppressed.

The diffusion coefficient in the diffusion between liquids is usually about 1 × 10 ⁻⁹ m ² / s. If the diffusion coefficient in the diffusion of the second solvent into the first solvent S is also equivalent, the viscosity after the ink-jet ink I adheres to the first solvent S is calculated based on the diffusion equation. It can be seen that the concentration of the second solvent in the ink-jet ink I ′ having increased is about tens of milliseconds to hundreds of tens of milliseconds until it becomes about half the concentration of the second solvent in the ink-jet ink I. Thereby, the viscosity of the inkjet ink I can be increased at high speed, and an image can be formed at a high speed of 500 mm / s or more when the elastic member E moves.

The greater the diffusion rate at which the second solvent diffuses into the first solvent S, the more the resin and coloring material diffuse into the first solvent S when the ink-jet ink I adheres to the first solvent S. can do. That is, the diffusion coefficient in the diffusion of the second solvent into the first solvent S is 1 × 10 ⁻⁹ to 1 × 10 ⁻¹¹ m ² / s under the conditions for actually forming an image in the image forming apparatus. It is preferable that At this time, the diffusion coefficient depends on the temperature and the viscosity, and the viscosity depends on the temperature.

  The region where the first solvent S is applied to the elastic member E is preferably substantially the same as the region where the ink jet ink I is adhered. Thereby, the usage-amount of the 1st solvent S can be reduced. Moreover, the transfer of the first solvent S to the paper P can be suppressed.

  The elastic member E may have a roughened surface.

  Further, instead of the elastic member E, a roller-like elastic member, a belt-like elastic member supported by a plurality of rollers, or the like may be used.

  In the present embodiment, it is an essential condition that the second solvent is soluble in the first solvent S, the resin is insoluble in the first solvent S, and is soluble in the second solvent. .

  In the present specification and claims, the second solvent is soluble in the first solvent means that the first solvent and the second solvent are added to the glass bottle in an environment of 25 ° C. and 1 bar. After stirring at a ratio of 1: 1, it refers to the state of being transparent and not separated when allowed to stand for 30 minutes.

  Further, in the present specification and claims, the resin is insoluble in the first solvent means that the first solvent and the resin were stirred in a glass bottle at a mass ratio of 99: 1 in an environment of 25 ° C. and 1 bar. After that, when left still for 1 hour, it means a state where solid matter is observed in the glass bottle.

  Furthermore, in the present specification and claims, the resin is soluble in the second solvent means that the second solvent and the resin are transparent at a mass ratio of 99: 1 in a glass bottle in an environment of 25 ° C. and 1 bar. When the mixture is heated and stirred until it is left to stand for one week, it means a state where no precipitate is generated at the bottom of the glass bottle.

  Now, there is a solubility parameter (SP value) as a characteristic value that is a measure of solubility and insolubility. In general, the smaller the SP value difference, the easier it is to dissolve, and the larger the SP value difference, the more difficult it is to dissolve.

  2 and 3 show a method for selecting the first solvent, the second solvent, and the resin.

In FIG. 2, the SP value of the resin is 11.0 (cal / cm ³ ) ^0.5 , and the range of the SP value of the solvent in which the resin is soluble is 9.0 to 12.0 (cal / cm ^3). ) ^0.5 . Here, if a solvent having an SP value of 9.5 (cal / cm ³ ) ^0.5 is selected as the second solvent, the resin is soluble in the second solvent. The range of the SP value of the solvent in which the second solvent is soluble is 7.0 to 11.0 (cal / cm ³ ) ^0.5 . Here, when a solvent having an SP value of 8.0 (cal / cm ³ ) ^0.5 is selected as the first solvent, the second solvent is soluble in the first solvent and the resin is , Insoluble in the first solvent.

In FIG. 3, the SP value of the resin is 11.0 (cal / cm ³ ) ^0.5 , and the range of the SP value of the solvent in which the resin is soluble is 9.0 to 12.0 (cal / cm ^3). ) ^0.5 . Here, if a solvent having an SP value of 10.0 (cal / cm ³ ) ^0.5 is selected as the second solvent, the resin is soluble in the second solvent. The range of the SP value of the solvent in which the second solvent is soluble is 9.0 to 17.0 (cal / cm ³ ) ^0.5 . Here, when a solvent having an SP value of 16.0 (cal / cm ³ ) ^0.5 is selected as the first solvent, the second solvent is soluble in the first solvent and the resin is , Insoluble in the first solvent.

  The SP value of the second solvent is preferably slightly higher than the lower limit of the SP value range in which the resin is soluble, or slightly lower than the upper limit of the SP value range in which the resin is soluble. Thereby, the viscosity of the inkjet ink I adhered to the first solvent S can be increased in a short time. This is thought to be because the resin precipitates all at once as the second solvent diffuses into the first solvent S.

  Further, the SP value of the first solvent S preferably has a large difference from the lower limit or the upper limit of the SP value range in which the resin is soluble. Thereby, the viscosity of the inkjet ink I adhered to the first solvent S can be increased in a short time. This is presumably because the first solvent S diffuses in the inkjet ink I and the resin is likely to precipitate.

  In addition, although soluble value and insolubility cannot be explained only by SP value, it is desirable to select a material by the above concept in a combination of materials to which the concept of SP value applies.

  In this embodiment, before the inkjet ink I ′ having increased viscosity is transferred to the paper P, at least a part of the mixed solvent S ′ is removed. Specifically, the roller-shaped liquid absorbing member A that absorbs the first solvent S and the second solvent is in contact with the elastic member E, or the liquid absorbing member A is in contact with the mixed solvent S ′. Then, the liquid absorbing member A absorbs at least a part of the mixed solvent S ′ (see FIG. 4). At this time, the inkjet ink I ′ having an increased viscosity forms a strong network between the resins. Therefore, even if the liquid absorbing member A contacts the inkjet ink I ′ having an increased viscosity, image distortion occurs. Can be suppressed.

  As described above, the concentration of the second solvent in the inkjet ink I ′ whose viscosity has increased after the inkjet ink I has adhered to the first solvent S is half the concentration of the second solvent in the inkjet ink I. It takes about a dozen milliseconds to a few tens of milliseconds.

  The time from when the ink jet ink I adheres to the first solvent S applied to the elastic member E until the liquid absorbing member A contacts the ink jet ink I ′ having increased viscosity is usually from several tens of milliseconds to one hundred. It is several tens of milliseconds or more. The time from when the ink jet ink I adheres to the first solvent S applied to the elastic member E until the liquid absorbing member A comes into contact with the ink jet ink I ′ whose viscosity has increased is from tens of milliseconds to hundreds of tens of millimeters. If it is less than 2 seconds, image distortion may occur.

  Since the liquid absorbing member A cannot absorb the first solvent S and the second solvent having a certain capacity or more, it is preferable to periodically replace the liquid absorbing member A.

  Since the absorption of the first solvent S and the second solvent by the liquid absorbing member A depends on the capillary force, the liquid absorbing member A is preferably a porous body.

  It is preferable that the surface energy of the liquid absorbing member A on the side of absorbing the liquid is smaller than the surface energy of the elastic member E on the side where the first solvent S is applied. Thereby, it is possible to suppress the occurrence of image disturbance due to the ink jet ink I ′ having increased viscosity formed on the elastic member E being transferred to the liquid absorbing member A.

  In consideration of reduction of friction between the liquid absorbing member A and the elastic member E, the rotation direction of the liquid absorbing member A is a forward direction with respect to the moving direction of the elastic member E on the contact surface or the proximity surface with the elastic member E. Preferably there is. On the other hand, considering the surface energy, tackiness, elasticity, contact pressure, physical properties of the ink jet ink I ′ having increased viscosity, and the like of the liquid absorbing member A and the elastic member E, the rotational direction of the liquid absorbing member A is the same as that of the elastic member E. The contact surface or the proximity surface may be in a direction opposite to the moving direction of the elastic member E.

  A plurality of liquid absorbing members A may be installed.

  Instead of the liquid absorbing member A, a belt-like liquid absorbing member supported by a plurality of rollers may be used.

  Further, instead of rotating the liquid absorbing member A, a web-like liquid absorbing member A ′ may be conveyed (see FIG. 5).

  Further, instead of periodically replacing the liquid absorbing member A, the mixed liquid S absorbed by the liquid absorbing member A is obtained by rotating the liquid absorbing member A in a state where the roller-like liquid recovery member R is in pressure contact. At least a part of 'may be released and recovered (see Fig. 6).

  At this time, even if the ink-jet ink I ′ having increased viscosity formed on the elastic member E is transferred to the liquid absorbing member A by bringing the blade-shaped cleaning member C into contact with the liquid absorbing member A, the elastic member E Contamination can be suppressed.

  In consideration of reduction of friction between the liquid recovery member R and the liquid absorption member A, the rotation direction of the liquid recovery member R is forward with respect to the rotation direction of the liquid absorption member A at the contact surface with the liquid absorption member A. Preferably there is. On the other hand, considering the surface energy, tackiness, elasticity, contact pressure, etc. of the liquid recovery member R and the liquid absorption member A, the rotation direction of the liquid recovery member R is the liquid absorption member A on the contact surface with the liquid absorption member A. The direction may be opposite to the rotation direction.

  Instead of the liquid recovery member R, a belt-like liquid recovery member supported by a plurality of rollers, a blade-like liquid recovery member, or the like may be used.

  Further, instead of the cleaning member C, a roller-shaped cleaning member, a belt-shaped cleaning member supported by a plurality of rollers, or the like may be used.

  Further, the cleaning member C can also serve as a liquid recovery member.

  Next, a second embodiment of the image forming method of the present invention will be described.

  In the present embodiment, the roller-shaped liquid non-absorbing member N that does not absorb the first solvent S and the second solvent is in contact with the elastic member E, or the liquid non-absorbing member N is mixed with the mixed solvent S ′. By rotating in a state of being close to the elastic member E so as to come into contact, at least a part of the mixed solvent S ′ is transferred to the liquid non-absorbing member N (see FIG. 7). Thereby, before transferring the inkjet ink I ′ having increased viscosity to the paper P, at least a part of the mixed solvent S ′ can be removed. At this time, since the inkjet ink I ′ having increased viscosity forms a strong network among the resins, even if the liquid non-absorbing member N contacts the inkjet ink I ′ having increased viscosity, the image is disturbed. Occurrence can be suppressed.

  In addition, by rotating the liquid non-absorbing member N in a state where the roller-shaped liquid collecting member R ′ is in pressure contact with the liquid non-absorbing member N, at least a part of the mixed solvent S ′ transferred to the liquid non-absorbing member N is dammed and collected. To do.

  Further, when the blade-like cleaning member C ′ is brought into contact with the liquid non-absorbing member A, even if the ink jet ink I ′ having increased viscosity formed on the elastic member E is transferred to the liquid non-absorbing member N, the elastic member E contamination can be suppressed.

  It is preferable that the surface energy of the liquid non-absorbing member N on the side where the miscible solvent S ′ is transferred is smaller than the surface energy of the elastic member E on the side where the first solvent S is applied. Thereby, it is possible to suppress the occurrence of image disturbance due to the inkjet ink I ′ having increased viscosity formed on the elastic member E being transferred to the liquid non-absorbing member N.

  Considering the ease of transfer of the mixed solvent S ′, the rotation direction of the liquid non-absorbing member N is opposite to the moving direction of the elastic member E on the contact surface or the proximity surface with the elastic member E. Is preferred. On the other hand, in consideration of the surface energy of the liquid non-absorbing member N and the elastic member E, tackiness, elasticity, contact pressure, physical properties of the ink jet ink I ′ having increased viscosity, the rotation direction of the liquid non-absorbing member N is the elastic member. The contact surface with E or the proximity surface may be forward with respect to the moving direction of the elastic member E.

  A plurality of liquid non-absorbing members N may be installed.

  Instead of the liquid non-absorbing member N, a belt-like liquid non-absorbing member supported by a plurality of rollers may be used.

  Considering reduction of friction between the liquid recovery member R ′ and the liquid non-absorbing member N, the rotation direction of the liquid recovery member R ′ is the same as the rotation direction of the liquid non-absorbing member N on the contact surface with the liquid non-absorbing member N. The forward direction is preferable. On the other hand, in consideration of the surface energy, tackiness, elasticity, contact pressure, etc. of the liquid recovery member R ′ and the liquid non-absorbing member N, the rotation direction of the liquid recovery member R ′ is the contact surface with the liquid non-absorbing member N. The direction opposite to the rotation direction of the liquid non-absorbing member N may be used.

  The material constituting the liquid recovery member R ′ is not particularly limited as long as the first solvent S and the second solvent can be transferred, and examples thereof include metals, resins, and rubbers.

  Instead of the liquid recovery member R ′, a belt-like liquid recovery member supported by a plurality of rollers, a blade-like liquid recovery member, or the like may be used.

  The material constituting the cleaning member C ′ is not particularly limited, and examples thereof include metals, resins, and rubbers.

  Instead of the cleaning member C ′, a roller-like cleaning member, a belt-like cleaning member supported by a plurality of rollers, or the like may be used.

  The cleaning member C ′ can also serve as a liquid recovery member.

  The viscosity of the inkjet ink I is usually about 1 to 20 mPa · s.

  The resin for the oil-based ink is not particularly limited, and examples thereof include polystyrene, polyester, epoxy resin, acrylic resin, a copolymer containing these in the skeleton, rosin-modified phenol resin, and alkyd resin.

  The second solvent for the oil-based ink is not particularly limited as long as the resin for the oil-based ink is soluble, but there are two solvents such as dimethyl succinate, diethyl succinate, dibutyl adipate, isobutyl adipate, dibutyl sebacate and the like. Examples include basic acid esters, fatty acid esters such as ethyl laurate, isopropyl myristate, and butyl palmitate.

  The first solvent S for oil-based ink is not particularly limited as long as the resin for oil-based ink is insoluble and the second solvent for oil-based ink is soluble, but tridecane, tetradecane, pentadecane, hexadecane. , High-boiling paraffinic hydrocarbons that are liquid at room temperature such as heptadecane, high-boiling olefinic hydrocarbons such as pentadecene, hexadecene, and heptadecene, dimethyl silicone oil, fatty acid ester-modified silicone oil, and the like. Good.

  Although it does not specifically limit as resin for water-based ink, Polyvinyl alcohol, polyvinylpyrrolidone, etc. are mentioned.

  The second solvent for water-based ink is not particularly limited as long as the resin for water-based ink is soluble, and examples thereof include glycols such as glycerin and butylene glycol.

  The first solvent S for water-based ink is not particularly limited as long as the resin for water-based ink is insoluble and the second solvent for water-based ink is soluble, but alcohol such as ethanol, isopropyl alcohol, etc. And the like.

  The coloring material may be either a dye or a pigment, but is preferably a pigment because it is difficult to diffuse into the first solvent S.

  The pigment is not particularly limited, but carbon black, phthalocyanine blue, monoazo yellow, disazo yellow, benzimidazole yellow, anthraquinone yellow, polyazo yellow, monoazo red, brilliant carmine 6B, anthraquinone red, dimethylquinacridone, etc. Can be mentioned.

  When a pigment is used as the color material, it is preferable to use a pigment dispersant in order to uniformly disperse it in the second solvent.

  The pigment dispersant is not particularly limited, and examples thereof include an alkyl ammonium type polymer dispersant, a block copolymer type polymer dispersant, and a phosphate ester salt dispersant.

  The paper P is not particularly limited, and examples thereof include special paper such as art paper, super art paper, dull art paper, super dull art paper, and coated paper, and plain paper such as medium quality paper, high quality paper, and PPC paper.

  In place of the paper P, a transparent film such as a PET film or a polypropylene film, or a metal sheet such as an aluminum sheet or a stainless sheet may be used.

  FIG. 8 shows a first embodiment of the image forming apparatus of the present invention.

  The image forming apparatus 10 includes an intermediate transfer belt 11, an inkjet head 12, an inkjet head 13, a liquid absorbing web 14, a pressure roller 15, and a cleaning blade 16. At this time, the inkjet head 12 discharges a first solvent (not shown) according to the image signal and applies it to the intermediate transfer belt 11. Further, the inkjet head 13 ejects inkjet ink (not shown) in accordance with the image signal and adheres it to the first solvent applied to the intermediate transfer belt 11. Further, the liquid absorbing web 14 is conveyed while being in contact with the intermediate transfer belt 11, thereby absorbing at least a part of a mixed solvent (not shown) formed on the intermediate transfer belt 11. Further, the pressure roller 15 transfers the ink-jet ink (not shown) whose viscosity has increased due to the ink-jet ink adhering to the first solvent to the paper P. Further, the cleaning blade 16 removes the inkjet ink, the mixed solvent, the paper dust, and the like remaining on the intermediate transfer belt 11 to which the inkjet ink having increased viscosity is transferred.

  The intermediate transfer belt 11 has an elastic layer (not shown) formed on a support (not shown).

  The material constituting the support of the intermediate transfer belt 11 is not particularly limited, but is a thermoplastic resin such as polyethylene terephthalate, a heat resistant resin such as polyimide, polyamideimide, or polyetherketone, stainless steel, nickel, aluminum, iron, or the like. Metal materials and the like.

  The material constituting the elastic layer of the intermediate transfer belt 11 is not particularly limited as long as the wettability with respect to the first solvent is good, and examples thereof include silicone rubber, NBR rubber, chloroprene rubber, urethane rubber, and fluorine rubber. .

  The intermediate transfer belt 11 may further have a release layer formed on the elastic layer.

  The material constituting the release layer is not particularly limited, but tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), tetrafluoroethylene- Fluorine such as ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-hexafluoropropylene polymer (FEP), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV) Based resins and the like.

  Further, the intermediate transfer belt 11 does not have to be formed with an elastic layer.

  The intermediate transfer belt 11 is supported at a constant tension by tension rollers 17A, 17B, and 17C.

  The material constituting the tension rollers 17A, 17B, and 17C is not particularly limited, and examples thereof include metals such as aluminum, iron, and stainless steel, alloys thereof, ceramics, and the like.

  At this time, when forming a monochrome image, the same image signal as that sent to the inkjet head 13 is sent to the inkjet head 12.

  When a color image is formed, an image signal obtained by converting the color image into a monochrome binary image is sent to the inkjet head 12.

  Note that the first solvent may be applied using a roller or the like instead of the inkjet head 12.

  The liquid absorbent web 14 is not particularly limited as long as it can absorb the first solvent S and the second solvent, and examples thereof include a nonwoven fabric. Especially, the nonwoven fabric by which surface treatments, such as a fluorine treatment, are performed is preferable.

  The liquid absorbing web 14 is transported by transport rollers 18A, 18B, and 18C.

  At this time, the liquid absorbent web 14 that has absorbed the miscible solvent is replaced.

  The pressure roller 15 has an elastic layer (not shown) formed on a support (not shown).

  The material constituting the cleaning blade 16 is not particularly limited, and examples thereof include metals, resins, and rubbers.

  FIG. 9 shows a second embodiment of the image forming apparatus of the present invention.

  The image forming apparatus 20 is similar to the image forming apparatus 10 except that the liquid absorbing roller 21, the liquid recovery roller 22, the liquid conveying roller 23, and the cleaning blade 24 are used instead of the liquid absorbing web 14 and the conveying rollers 18A, 18B, and 18C. It is the same configuration. At this time, the liquid absorption roller 21 absorbs at least a part of the mixed solvent formed on the intermediate transfer belt 11 by rotating while being in contact with the intermediate transfer belt 11. Further, the liquid recovery roller 22 rotates in a state of being in pressure contact with the liquid absorption roller 21 to release at least a part of the mixed solvent absorbed by the liquid absorption roller 21. Further, the liquid transport roller 23 is formed with a spiral groove, and transports the mixed solvent released by the liquid absorption roller 21 to a collection space (not shown) in the depth direction of the paper surface. The cleaning blade 24 cleans the liquid absorbing roller 21.

  The liquid absorbing roller 21 has a liquid absorbing layer (not shown) formed on a support (not shown).

  The material constituting the support of the liquid absorbing roller 21 is not particularly limited, but is a thermoplastic resin such as polyethylene terephthalate, a heat resistant resin such as polyimide, polyamideimide, or polyetherketone, stainless steel, nickel, aluminum, iron, or the like. Metal materials and the like.

  The material constituting the liquid absorbing layer of the liquid absorbing roller 21 is not particularly limited as long as it can absorb the first solvent S and the second solvent, and examples thereof include a resin.

  The liquid absorbing layer of the liquid absorbing roller 21 is preferably subjected to surface treatment such as fluorine treatment.

  The liquid recovery roller 22 has an elastic layer (not shown) formed on a support (not shown).

  The material constituting the support of the liquid recovery roller 22 is not particularly limited, but is a thermoplastic resin such as polyethylene terephthalate, a heat resistant resin such as polyimide, polyamideimide, or polyetherketone, stainless steel, nickel, aluminum, iron, or the like. Metal materials and the like.

  The material constituting the elastic layer of the liquid recovery roller 22 is not particularly limited as long as the wettability with respect to the first solvent and the second solvent is good. Silicone rubber, NBR rubber, chloroprene rubber, urethane rubber, fluorine Rubber etc. are mentioned.

  The liquid recovery roller 22 may further include a release layer on the elastic layer.

  The material constituting the release layer is not particularly limited, but tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), tetrafluoroethylene- Fluorine such as ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-hexafluoropropylene polymer (FEP), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV) Based resins and the like.

  Further, the liquid recovery roller 22 may not have an elastic layer formed thereon.

  The material constituting the liquid transport roller 23 is not particularly limited as long as the wettability with respect to the first solvent and the second solvent is good, but a thermoplastic resin such as polyethylene terephthalate, polyimide, polyamideimide, polyetherketone And heat-resistant resins such as stainless steel, nickel, aluminum, iron, and other metal materials.

  The material constituting the cleaning blade 24 is not particularly limited, and examples thereof include metals, resins, and rubbers.

  FIG. 10 shows a third embodiment of the image forming apparatus of the present invention.

  The image forming apparatus 30 uses the liquid non-absorbing roller 31, the liquid recovery roller 32, the liquid conveying roller 33, and the cleaning blade 34 in place of the liquid absorbing web 14 and the conveying rollers 18A, 18B, and 18C. It is the same composition as. At this time, the liquid non-absorbing roller 31 is rotated while being in contact with the intermediate transfer belt 11, thereby transferring at least a part of the mixed solvent formed on the intermediate transfer belt 11. Further, the liquid recovery roller 32 rotates in a state of being in pressure contact with the liquid non-absorbing roller 31, thereby blocking at least a part of the mixed solvent transferred to the liquid non-absorbing roller 31. Further, the liquid transport roller 33 is formed with a spiral groove, and transports the mixed solvent blocked by the liquid recovery roller 32 to a recovery space (not shown) in the depth direction of the paper surface. The cleaning blade 34 cleans the liquid non-absorbing roller 31.

  The liquid non-absorbing roller 31 has an elastic layer (not shown) formed on a support (not shown).

  The material constituting the support of the liquid non-absorbing roller 31 is not particularly limited, but is a thermoplastic resin such as polyethylene terephthalate, a heat resistant resin such as polyimide, polyamideimide, or polyetherketone, stainless steel, nickel, aluminum, or iron. Examples thereof include metal materials.

  The material constituting the elastic layer of the liquid non-absorbing roller 31 is not particularly limited as long as it can absorb the first solvent and the second solvent. Silicone rubber, NBR rubber, chloroprene rubber, urethane rubber And fluororubber. Of these, silicone rubber, silicone-modified EPDM, and fluororubber are preferable.

  The liquid non-absorbing roller 31 may further have a release layer formed on the elastic layer.

  The material constituting the release layer is not particularly limited, but tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), tetrafluoroethylene- Fluorine such as ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-hexafluoropropylene polymer (FEP), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV) Based resins and the like.

  Further, the liquid non-absorbing roller 31 does not have to be formed with an elastic layer.

  The liquid recovery roller 32 has an elastic layer (not shown) formed on a support (not shown).

  The material constituting the support of the liquid recovery roller 32 is not particularly limited, but is a thermoplastic resin such as polyethylene terephthalate, a heat resistant resin such as polyimide, polyamideimide, or polyetherketone, stainless steel, nickel, aluminum, iron, or the like. Metal materials and the like.

  The material constituting the elastic layer of the liquid recovery roller 32 is not particularly limited as long as the wettability with respect to the first solvent and the second solvent is good. Silicone rubber, NBR rubber, chloroprene rubber, urethane rubber, fluorine Rubber etc. are mentioned.

  The liquid recovery roller 32 may further include a release layer on the elastic layer.

  The material constituting the release layer is not particularly limited, but tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), tetrafluoroethylene- Fluorine such as ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-hexafluoropropylene polymer (FEP), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV) Based resins and the like.

  Further, the liquid recovery roller 32 may not have an elastic layer.

  The material constituting the liquid transport roller 33 is not particularly limited as long as the wettability with respect to the first solvent and the second solvent is good, but a thermoplastic resin such as polyethylene terephthalate, polyimide, polyamideimide, polyetherketone And heat-resistant resins such as stainless steel, nickel, aluminum, iron, and other metal materials.

  The material constituting the cleaning blade 34 is not particularly limited, and examples thereof include metals, resins, and rubbers.

  Examples of the present invention are shown below. In addition, in a present Example, a part means a mass part.

[Example 1-1]
While stirring using a stirrer, 12 parts of low molecular weight polystyrene ST-95 (manufactured by Sanyo Chemical Co., Ltd.) having an SP value of 9.2 (cal / cm ³ ) ^0.5 was added to an SP value of 8.6 (cal / cm ^3). ) After being dissolved in 82 parts of ^0.5 isopropyl myristate, 4 parts of pigment dispersant DISPERBYK-2155 (manufactured by Big Chemie Japan) was dissolved. Next, the obtained solution, 2 parts of carbon black # 2350 (manufactured by Mitsubishi Chemical Corporation) and zirconia beads having a diameter of 1 mm were placed in a container, and then dispersed for 12 hours using a ball mill. Furthermore, it filtered using the filter with a hole diameter of 0.45 micrometer, and obtained the inkjet ink.

An image was formed using the image forming apparatus 10. At this time, fatty acid ester-modified silicone oil TSF410 (manufactured by Momentive) having an SP value of 8.1 (cal / cm ³ ) ^0.5 was used as the first solvent. As the intermediate transfer belt 11, an endless belt in which an elastic layer made of silicone rubber having a thickness of 0.5 mm is formed on a nickel support having a thickness of 0.07 mm was used. Furthermore, GEN4 (manufactured by Ricoh Industry) was used as the inkjet heads 12 and 13. Further, as the liquid absorbent web 14, a sheet-like ruby cell (Toyo Polymer Co., Ltd.) coated with silicone having a thickness of 1 mm was used. Further, as the pressure roller 15, a roller in which an elastic layer made of urethane rubber having a thickness of 5 mm is formed on a cylindrical support made of SUS having an outer diameter of 50 mm was used. Further, as the cleaning blade 16, a blade made of urethane rubber was used. Further, as the paper P, A4 PPC paper Mypaper (manufactured by Ricoh) was used. In addition, the inkjet heads 12 and 13 were arranged so that the time from application of the first solvent to the intermediate transfer belt 11 to adhesion of the inkjet ink to the first solvent was 0.1 second. Furthermore, the inkjet head 13 and the liquid absorbent web 14 were arranged so that the time from when the inkjet ink was attached to the first solvent to when the mixed solvent was absorbed by the liquid absorbent web 14 was 1.0 second. Further, after applying about 18 pL of the first solvent to the intermediate transfer belt 11, about 14 pL of the ink-jet ink was adhered to the first solvent.

  As a result, an image without blur was formed on the paper P, and the image was not disturbed.

  Note that isopropyl myristate is soluble in fatty acid ester-modified silicone oil TSF410 (manufactured by Momentive), and low molecular weight polystyrene ST-95 (manufactured by Sanyo Chemical Co., Ltd.) is dissolved in fatty acid ester-modified silicone oil TSF410 (manufactured by Momentive). It was insoluble and confirmed to be soluble in isopropyl myristate.

  In addition, one drop of ink-jet ink was dropped with a dropper onto a glass slide coated with fatty acid ester-modified silicone oil TSF410 (manufactured by Momentive) in an environment of 25 ° C. and 1 bar, and the pigment was encapsulated when observed with an optical microscope. The resin was deposited in the state.

[Comparative Example 1]
An image was formed in the same manner as in Example 1-1 except that the first solvent S was not applied.

  As a result, an image with blurring due to feathering is formed on the paper P, and the image is disturbed.

[Example 1-2]
An image was formed in the same manner as in Example 1-1 except that a sheet-like ruby cell (manufactured by Toyo Polymer Co., Ltd.) that was not coated with silicone was used as the liquid absorbent web 14.

  As a result, an image without blur was formed on the paper P, but the image was disturbed.

[Example 2-1]
An image was formed in the same manner as in Example 1-1 except that the image forming apparatus 20 was used instead of the image forming apparatus 10. At this time, as the liquid absorbing roller 21, a liquid absorbing layer made of a sheet-like ruby cell (manufactured by Toyo Polymer Co., Ltd.) having a thickness of 1 mm on a SUS cylindrical support having an outer diameter of 50 mm. A formed roller was used. Further, as the liquid recovery roller 22, a SUS roller having an outer diameter of 50 mm was used. Further, as the liquid transport roller 23, a SUS transport screw having an outer diameter of 10 mm was used. Further, as the cleaning blade 24, a blade made of urethane rubber was used.

  As a result, an image without blur was formed on the paper P, and the image was not disturbed.

[Comparative Example 2]
An image was formed in the same manner as in Example 2-1, except that the first solvent S was not applied.

  As a result, an image with blurring due to feathering is formed on the paper P, and the image is disturbed.

[Example 2-2]
An image is formed in the same manner as in Example 2-1, except that a roller on which a liquid absorption layer made of a sheet-like ruby cell (manufactured by Toyo Polymer Co., Ltd.) not coated with silicone is used as the liquid absorption roller 21. did.

  As a result, an image without blur was formed on the paper P, but the image was disturbed.

[Example 3-1]
An image was formed in the same manner as in Example 1-1 except that the image forming apparatus 30 was used instead of the image forming apparatus 10. At this time, a fluorine-treated SUS roller having an outer diameter of 50 mm was used as the liquid non-absorbing roller 31. As the liquid recovery roller 32, a roller in which an elastic layer made of urethane rubber having a thickness of 1 mm is formed on a cylindrical support made of SUS having an outer diameter of 50 mm is used. Further, as the liquid transport roller 33, a SUS transport screw having an outer diameter of 10 mm was used. Further, as the cleaning blade 34, a blade made of urethane rubber was used.

  As a result, an image without blur was formed on the paper P, and the image was not disturbed.

[Comparative Example 3]
An image was formed in the same manner as in Example 3-1, except that the first solvent S was not applied.

  As a result, an image with blurring due to feathering is formed on the paper P, and the image is disturbed.

[Example 3-2]
An image was formed in the same manner as in Example 3-1, except that a non-fluorinated SUS roller was used as the liquid non-absorbing roller 31.

  As a result, an image without blur was formed on the paper P, but the image was disturbed.

A, A ′ Liquid absorbing member C, C ′ Cleaning member I Inkjet ink I ′ Inkjet ink with increased viscosity E Elastic member N Liquid non-absorbing member P Paper R, R ′ Liquid recovery member S First solvent S ′ Mixed solvent 10, 20, 30 Image forming apparatus 11 Intermediate transfer belt 12, 13 Inkjet head 14 Liquid absorbing web 15 Pressure roller 16 Cleaning blade 17A, 17B, 17C Tension roller 18A, 18B, 18C Conveying roller 21 Liquid absorbing roller 22, 32 Liquid Collection rollers 23, 33 Liquid transport rollers 24, 34 Cleaning blade 31 Liquid non-absorbing roller

JP 2011-143705 A

Claims (12)

An intermediate transfer member;
Application means for applying a first solvent to the intermediate transfer member;
An ejection unit that ejects inkjet ink and adheres to the first solvent applied to the intermediate transfer member;
A transfer means for transferring the inkjet ink attached to the first solvent to a recording medium;
The inkjet ink includes a second solvent, a resin, and a color material,
The second solvent is soluble in the first solvent;
The resin is insoluble in the first solvent and soluble in the second solvent;
Before transferring the inkjet ink attached to the first solvent to a recording medium, remove at least a part of the first solvent applied to the intermediate transfer member and the second solvent attached to the first solvent. An image forming apparatus, further comprising a liquid removing unit.   The image forming apparatus according to claim 1, wherein the first solvent is capable of precipitating the resin when the inkjet ink is dropped. The liquid removing means has a liquid absorbing member that absorbs the first solvent and the second solvent,
3. The liquid absorbing member absorbs at least a part of the first solvent applied to the intermediate transfer member and the second solvent attached to the first solvent. 4. Image forming apparatus.   The image forming apparatus according to claim 3, wherein the liquid absorbing member is a porous body.   The image forming apparatus according to claim 3, wherein the liquid removing unit includes a liquid recovery member that discharges and recovers the liquid absorbed by the liquid absorption member.   6. The surface energy of the liquid absorbing member on the side that absorbs liquid is smaller than the surface energy of the intermediate transfer member on the side on which the first solvent is applied. The image forming apparatus described in 1.   The image forming apparatus according to claim 3, wherein the liquid removing unit includes a cleaning member that cleans the liquid absorbing member. The liquid removing means has a liquid non-absorbing member that does not absorb the first solvent and the second solvent,
The first solvent applied to the intermediate transfer member and at least a part of the second solvent attached to the first solvent are transferred to the liquid non-absorbing member. Image forming apparatus.   The image forming apparatus according to claim 8, wherein the liquid removing unit includes a liquid recovery member that dams and recovers the liquid transferred to the liquid non-absorbing member.   10. The image according to claim 8, wherein a surface energy of the liquid non-absorbing member on a liquid transfer side is smaller than a surface energy of the intermediate transfer member on a side to which the first solvent is applied. Forming equipment.   The image forming apparatus according to claim 8, wherein the liquid removing unit includes a cleaning member that cleans the liquid non-absorbing member. Applying a first solvent to the intermediate transfer member;
Discharging ink jet ink to adhere to the first solvent applied to the intermediate transfer member;
Transferring the ink-jet ink attached to the first solvent to a recording medium;
The inkjet ink includes a second solvent, a resin, and a color material,
The second solvent is soluble in the first solvent;
The resin is insoluble in the first solvent and soluble in the second solvent;
Before transferring the inkjet ink attached to the first solvent to a recording medium, remove at least a part of the first solvent applied to the intermediate transfer member and the second solvent attached to the first solvent. And an image forming method.

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