JP4054721B2 - Image forming method and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an image forming method using an ink jet recording method.Law and paintingImage forming equipmentIn placeIn particular, the present invention relates to a technique for forming an image on a recording medium using an intermediate transfer member in order to make it less susceptible to the ink absorption amount of the recording medium.
[0002]
[Prior art]
At present, the mainstream of image formation using paper as a recording medium is offset printing. Offset printing is a technology suitable for mass production. That is, it is possible to make a plate that is the basis of an image and make about 9000 copies per minute by a printing press. In printing, it takes time and cost in the plate making process, and the disadvantages such as the need for a large amount of capital investment in the printing press are almost all of the cost and speed per printed matter due to the large amount of products produced. There was no effect. It can be said that such offset printing was very matched to previous market demands.
[0003]
However, as in recent years, as the diversification of information and multi-product and small-lot production progress, the plate-making cost for each printed material increases, resulting in a problem that it becomes expensive. Furthermore, since the immediacy of information has become more important, there is an increasing demand for shortened delivery times for printed materials. Current offset printing has a long lead time from document preparation to plate making and printing preparation (stabilization of the apparatus), so even if the number of printed copies is small, it does not lead to a short delivery time. In addition, it requires enormous capital investment, and all process operations require highly skilled skills. Therefore, production bases are limited, and it takes time to reach the customer's hands after printing is completed. It was.
[0004]
In order to meet the market demand as described above, the ink jet recording method is attracting attention as a suitable technique. In other words, the inkjet recording method is suitable for printing a small number of copies because it does not use a plate, and does not require large-scale equipment and does not require high technical knowledge. This makes it an expected information recording method.
[0005]
At present, printed matter by inkjet recording is inferior to offset printed matter, such as glossiness of printed matter, printing on thin paper, double-sided printability, and printing cost. Therefore, if these points can be improved, progress to commercial printing by the ink jet recording method can be expected.
[0006]
The glossiness of the printed material is greatly influenced by the surface smoothness of the printing paper (recording medium). Conventionally, ink jet recording systems often use penetrating ink that is fixed by penetrating into printing paper. At this time, since the ink coloring material is fixed following the surface of the printing paper, it is necessary to use a printing paper with high surface smoothness in order to give a glossy feeling.
[0007]
On the other hand, printing paper with high surface smoothness generally has low ink absorbability. This is because the penetrating ink is normally absorbed by a capillary phenomenon. When printing on paper with a small amount of ink absorption, the ink will not be absorbed by the paper and will remain on the surface, causing a phenomenon called bleeding where the ink droplets recorded adjacent to each other will be mixed, or the ink that has landed first A phenomenon called beading in which the droplets are attracted to the ink droplets that have landed later occurs, resulting in a decrease in image formation quality and poor drying. Therefore, at present, it is very difficult to form an image on the printing paper having high surface smoothness by the ink jet recording method without causing these problems.
[0008]
By the way, the ink ejection method of the ink jet recording method includes an on-demand method using an electrothermal conversion element (heating element) or an electromechanical conversion element (piezo element) in addition to the continuous method. Only low-viscosity ink can be ejected. This is because the ink used in the ink jet recording system is required to have high fluidity in the ink jet head in order to satisfy discharge suitability. On the other hand, as described above, low flow characteristics are required for the ink on the surface of the recording medium in order to prevent mixing with adjacent ink droplets or attracting ink droplets. As described above, in the case of the ink jet system, although ink with high fluidity is ejected onto a recording medium, the fluidity of the ink must be lowered on the recording medium, and conflicting characteristics are required.
[0009]
In order to satisfy these conflicting requirements, an ink image is formed on a transfer body (also referred to as an intermediate transfer body), the ink image formed on the transfer body is transferred to a desired recording medium, and the desired recording medium A method for forming an ink image (an image forming method using an intermediate transfer member) has been proposed. In this method, the ink ejected from the ink jet head is once attached to the transfer body to form an ink image in a state where the fluidity of the ink is lowered to some extent, and then the ink image is transferred from the transfer body to the recording medium. It is.
[0010]
When such a transfer body is used, the surface of the transfer body has a low ink absorbability, especially non-ink absorption due to the demand for ink transfer from the transfer body to the recording medium and the cleaning performance of the transfer body after transfer. It is desirable to be a surface. However, simply using a transfer body having such a non-ink-absorbing surface causes the ink to flow on the transfer body, and it is difficult to satisfactorily hold the ink image on the transfer body. That is, if the surface of the transfer body is made a non-ink absorbing surface in order to improve the transferability of the ink image from the intermediate transfer body, it is difficult to improve the retention of the ink image on the intermediate transfer body. On the other hand, if the surface of the transfer body is made to have a high ink absorbability in order to improve the retention of the ink image on the intermediate transfer body, the transferability of the ink image from the intermediate transfer body is improved. Difficult to do.
[0011]
As described above, in the image forming method using the intermediate transfer member, it is possible to achieve both high retention of the ink image on the intermediate transfer member and high transferability of the ink image from the intermediate transfer member on the recording medium. This is important for improving the quality of the ink image. However, a high-quality ink can be used in various recording media regardless of the type of the recording medium, by achieving both high retention of the ink image on the intermediate transfer body and high transferability of the ink image from the intermediate transfer body. An image that can be formed has not been realized yet.
[0012]
For example, Patent Document 1 proposes a technique for heating a transfer body to concentrate ink on the transfer body and reducing ink fluidity on the transfer body. However, when the transfer body is simply heated, the degree of decrease in the ink fluidity is small, and the ink image is instantly blurred on the transfer body. That is, the retention of the ink image on the transfer body is poor, and accordingly, the ink image on the recording medium after transfer cannot be made high quality. In addition, there still remains a problem such as ejection failure due to the heat of the transfer member being transferred to the inkjet head and drying the nozzles for ejecting ink, and it has not been put into practical use.
[0013]
Further, as described in Patent Document 2, a method of discharging molten hot melt ink by using hot melt ink and heating an ink jet head and an ink supply system has also been proposed. However, in this case, due to the large thickness of the adhered ink, the ink image on the recording medium after transfer is uncomfortable, and the ink image on the recording medium after transfer is of high quality as in Patent Document 1. I can't. In addition, when hot melt ink is used, it is necessary to obtain a preferable melted state by heating, but there are many points to be improved such as a long preparation time and restrictions on ink components.
[0014]
[Patent Document 1]
JP-A-5-330035
[Patent Document 2]
JP-A-7-223312
[Patent Document 3]
Japanese Examined Patent Publication No. 61-36783
[0015]
[Problems to be solved by the invention]
As is clear from the above, in printing by the ink jet recording method, a method using an intermediate transfer member is effective in order to increase the degree of freedom of the recording medium. In order to improve the quality of the ink image on the recording medium, there still remains a problem that must be improved. In particular, to achieve both high retention of the ink image on the intermediate transfer body and high transferability of the ink image from the intermediate transfer body, and to make the ink image on the recording medium after transfer high quality, This is one of the important issues to be improved.
[0016]
The present invention has been made in view of the problems as described above, and without sacrificing the high recordability of the ink jet recording method, it can be used for a wide range of recording media regardless of the ink absorption amount of the recording medium. In order to enable image recording, high-quality ink images can be printed on various recording media by achieving both high retention of the ink image on the intermediate transfer member and high transferability of the ink image from the intermediate transfer member. An object is to provide an image forming method, an image forming apparatus, an intermediate transfer member used in the image forming method, and a surface modification method for the intermediate transfer member.
[0017]
Specifically, an image is formed on an intermediate transfer member having a non-adhesive surface layer without causing bleeding or beading, and then the ink from which moisture has been removed is transferred to a recording medium in good condition. Is to be able to.
[0018]
[Means for Solving the Problems]
  Therefore, the image forming method of the present invention is
  A step of subjecting the intermediate transfer member to a plasma treatment and a surfactant treatment;
  On the intermediate transfer body subjected to the plasma treatment and the surfactant application treatmentApplying a liquid for reducing the fluidity of the ink on the intermediate transfer member;
  In the intermediate transfer body provided with the liquid,A step of ejecting ink to form an image;
  SaidTransferring the image formed on the intermediate transfer member to a recording medium;
It is characterized by comprising.
[0019]
  The image forming method of the present invention includes
  Performing a plasma treatment and a surfactant application treatment on the surface of the intermediate transfer body in order to hydrophilize the surface of the intermediate transfer body having a surface containing at least one material of fluorine rubber or silicone rubber;
  A step of applying a liquid that reacts with ink on the intermediate transfer member subjected to the plasma treatment and the surfactant application treatment;
  Forming an image by ejecting ink onto the intermediate transfer member to which the liquid is applied using an inkjet recording means;
  Transferring the image formed on the intermediate transfer member to a recording medium;
It is characterized by comprising.
  Furthermore, the image forming method of the present invention includes:
  A step of applying a liquid that reacts with the ink on the intermediate transfer body subjected to the plasma treatment and the surfactant application treatment;
  Forming an image by ejecting ink onto the intermediate transfer body provided with the liquid using an ink jet recording means;
  Transferring the image formed on the intermediate transfer member to a recording medium;
It is characterized by comprising.
  In addition, the image forming method of the present invention includes:
  The fluidity of the ink on the intermediate transfer member having a surface containing at least one material of fluorine rubber or silicone rubber, the surface of which is subjected to plasma treatment and surfactant application treatment Applying a liquid for lowering,
  Forming an image by ejecting ink onto the intermediate transfer body provided with the liquid using an ink jet recording means;
  Transferring the image formed on the intermediate transfer member to a recording medium;
It is characterized by comprising.
  The image forming apparatus according to the present invention includes:
  Means for applying a liquid for reducing the fluidity of the ink on the intermediate transfer member on the intermediate transfer member subjected to the plasma treatment and the surfactant application treatment;
  Means for forming an image by ejecting ink onto the intermediate transfer member provided with the liquid;
  A transfer portion for transferring an image formed on the intermediate transfer member to a recording medium;
It is characterized by comprising.
  Furthermore, the image forming apparatus of the present invention includes:
  Means for applying a liquid that reacts with ink to an intermediate transfer member having a surface containing at least one material of fluorine rubber or silicone rubber, and having been subjected to plasma treatment and surfactant application treatment on the surface When,
  Means for forming an image by ejecting ink to the intermediate transfer body provided with the liquid using an ink jet recording means;
  A transfer portion for transferring an image formed on the intermediate transfer member to a recording medium;
It is characterized by having.
[0020]
In the present specification, the “recording medium” refers not only to paper used in a general printing apparatus but also to a wide range of materials that can accept cloth, plastic film, and other inks.
[0021]
In addition, as an ink jet recording means applied to the present invention, a form in which ink is ejected by forming a bubble by causing film boiling in the ink using thermal energy generated by the electrothermal transducer, an electromechanical transducer Ink jet heads according to various forms proposed for ink jet recording, such as a form for ejecting ink according to the above, a form for forming and ejecting ink droplets using static electricity or air current, and the like, but in particular from the viewpoint of miniaturization, an electrothermal transducer Those utilizing the above are preferably used.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0023]
1. Overview of image forming equipment
FIG. 1 is a schematic diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an intermediate transfer member that is rotationally driven in the direction of arrow F around an axis 1A. The surface has been subjected to a hydrophilic treatment by performing a surface modification by applying a plasma treatment and a surfactant in advance. Layer 2 is included. Reference numeral 3 in FIG. 1 indicates an atmospheric pressure plasma processing apparatus, and an additional surface modification process is performed on the surface layer 2 at an appropriate interval together with the coating apparatus denoted by reference numeral 4, and the surface modification effect is obtained according to the number of printing processes. compensate.
[0024]
Although not shown in FIG. 1, a cleaning unit may be disposed between the coating device 4 and the coating device 5 in order to remove surplus of the surfactant supplied by the coating device 4. Is possible. Further, when the interval for performing the additional surface modification treatment can be increased, the cleaning unit 13 provided for cleaning the surface of the intermediate transfer member after the ink image transfer may also be used. The process portion (in the example of FIG. 1, one rotation of the intermediate transfer member 1) may be fed idle.
[0025]
Thereafter, the ink viscosity increasing component is applied by the coating device 5 disposed in contact with the surface of the intermediate transfer body 1. Furthermore, after these components are applied, ink is ejected from the inkjet recording unit 6 as, for example, droplets, and an image (mirror image) is formed on the surface of the intermediate transfer body 1. Then, the recording surface of the recording medium 10 is brought into contact with the image formed on the intermediate transfer body 1, and the image is transferred and formed on the recording medium 10 by applying pressure from the back surface side by the pressure roller 11.
[0026]
In the apparatus illustrated in FIG. 1, a water removal promoting device 8 in the form of a blower is disposed for the purpose of evaporating and removing water or solvent components in the ink constituting the image on the intermediate transfer body 1. In addition to this, or instead of this, a heating roller 9 that heats by contacting the back surface of the hollow intermediate transfer member 1 can also be used.
[0027]
The recording medium 10 on which image recording has been performed through the intermediate transfer member 1 as described above has excellent surface smoothness by being pressed by the fixing roller 12. Further, by heating with the fixing roller 12, it is possible to immediately give the printed matter robustness.
[0028]
Further, in the apparatus illustrated in FIG. 1, the intermediate transfer member after the ink image is transferred to the recording medium 10 is washed by the next-stage cleaning unit 13 in preparation for receiving the next image.
[0029]
In the conventional ink jet recording apparatus, the image state changes due to the ink absorption amount of the recording medium, so that the recording medium to be used may be limited. On the other hand, since the offset printing apparatus is intended to provide a large amount of the same printed matter, it sometimes lacks the flexibility of recording such as performing different image output for each sheet.
[0030]
On the other hand, as is apparent from the embodiment embodied in the image forming apparatus as described above, the present invention can perform high-quality image recording on a wide range of media without being limited by the ink absorption amount of the recording media. Therefore, it is possible to form an image that effectively utilizes the advantage of the ink jet recording method that is excellent in recordability, such that a desired printed matter can be obtained immediately.
[0031]
2. Process description
The image forming apparatus forms an image on the intermediate transfer member by a step of performing surface modification of the intermediate transfer member 1 by plasma treatment and surfactant application (hereinafter referred to as step (a)) and an ink jet recording method. It includes means for performing a step (hereinafter referred to as step (b)) and a step of transferring an ink image formed on the intermediate transfer body 1 to a recording medium (hereinafter referred to as step (c)). . Hereinafter, these steps (a) to (c) to the implementation means will be described in detail with specific examples.
[0032]
2.1 Step (a)
Step (a) is a step of subjecting the surface layer material of the intermediate transfer member containing at least one of a fluorine compound and a silicone compound to surface modification by plasma treatment and surfactant application treatment.
[0033]
Here, in the embodiment of FIG. 1, in addition to the rigidity and dimensional accuracy that can withstand the pressurization during transfer, the characteristics required for reducing rotational inertia and improving control responsiveness, etc. The intermediate transfer member 1 is configured by using a light metal drum such as an alloy as a support for the surface layer of the intermediate transfer member and providing the surface layer 2 on the side surface of the drum.
[0034]
However, the intermediate transfer member or the support of the surface layer thereof may be any material as long as the surface layer can be at least in line contact with the recording medium, and is adapted to the form of the image forming apparatus to be applied or the transfer to the recording medium. For example, a roller shape, a belt shape, a sheet shape, or the like can also be used. Further, not only those that are in line contact, but also a material having a large elastic deformation such as a pad used in pad printing can be used as the intermediate transfer member.
[0035]
The material used for the surface layer 2 preferably contains either fluorine or a silicone compound. Since these compounds have excellent releasability with respect to ink, they have an excellent transfer rate when transferring an ink image. The fluorine or silicone compound described here is expressed including these oils, and materials containing these oils are particularly important materials capable of increasing the transfer rate. The releasability refers to a state where the ink image can be removed without being fixed to the surface of the intermediate transfer member. The higher the releasability, the more advantageous in terms of cleaning load and ink transfer rate. On the other hand, in general, the higher the releasability, the lower the critical surface tension of the material, and even if liquid such as ink adheres, it tends to be repelled and it is difficult to hold an image. The surface containing a fluorine or silicone compound, which is a releasable material preferably used in the present invention, has physical properties before surface treatment and has a critical surface tension of 30 mN / m or less, or a water repellency with a water contact angle of 70 ° or more. Indicates. In other words, the intermediate transfer member in the present invention does not form an image even if the ink is applied on the intermediate transfer member as long as a normal means is used before the surface treatment is performed. A material having a low ink image retention property is preferable.
[0036]
Specifically, the surface layer 2 can be formed by subjecting the surface of the intermediate transfer member support to a surface treatment such as fluorine treatment or application of silicone oil. It is preferable to use the surface layer 2 formed of the above material because higher transfer efficiency can be achieved. Specifically, fluorine rubber or silicone rubber containing an oil component can be suitably used. There are various types of silicone rubbers such as a vulcanization type, a one-component curable type, and a two-component curable type, and any of them can be suitably used. The rubber hardness of the surface layer material made of the elastic body is affected by the thickness and hardness of the recording medium 10 brought into contact therewith, and is preferably optimized for each. However, the durometer type A (JIS) An effect can be obtained by using a rubber having a rubber hardness in the range of 10 to 100 ° according to K 6253), and most of the recording paper can be used in a range of 40 to 80 °.
[0037]
In the step (a), surface modification is performed by applying plasma treatment and surfactant application treatment to the surface layer 2 of the intermediate transfer member 1 configured as described above. A material having excellent releasability, such as a fluorine compound or a silicone compound, generally has a characteristic of low critical surface tension, and repels liquids such as ink and ink thickening components described later. Therefore, an ink image cannot be formed on the intermediate transfer member as it is. Therefore, ink repelling is suppressed by performing surface modification by plasma treatment and surfactant application treatment. As the plasma processing means, a type in which processing is performed under atmospheric pressure or a reduced pressure atmosphere is generally used, and both are preferably used. However, the means for performing plasma processing under atmospheric pressure is directly mounted in the image forming apparatus as in the plasma processing apparatus 3 of FIG. 1, and an additional surface is provided along with the deterioration of the surface characteristics according to the number of printing processes. It is effective because it can be modified. The plasma treatment mentioned here includes corona discharge treatment that can activate oxygen in the atmosphere and generate hydroxyl groups on the surface.
[0038]
The surface modification is completed by applying a surfactant after the plasma treatment. As a result, the surface modification effect can be sustained over a long period of time. Any surfactant can be used, for example, general cationic surfactants, anionic surfactants, nonionic surfactants, amphoteric surfactants, fluorine surfactants. , And silicone surfactants can be used.
[0039]
As a means for applying the surfactant, roll coating, doctor coating, spray coating, or the like is preferable in order to enable continuous application as in the coating apparatus 4 in FIG. Depending on the case, the same effect can be obtained even by performing dip coating as a batch process.
[0040]
This surface modification means has an effect of not reducing or improving the ink transfer rate when transferring an image formed on the intermediate transfer body, which is a subsequent step, to a recording medium, as well as a mere hydrophilic treatment.
[0041]
The plasma treatment under reduced pressure and the hydrophilization treatment by applying a surfactant are disclosed in Patent Document 3 as a target limited to silicone rubber, but the present invention is different from this, and not only the hydrophilization. In addition, it can be used as an intermediate transfer member by simultaneously improving ink transferability. Therefore, there is a clear difference not only in the idea of the invention but also in the selected material and the restriction of the environmental pressure of the plasma treatment.
[0042]
The mechanism by which favorable effects can be obtained by such selected materials and selected surface modification means has not been completely elucidated so far. However, in the presence of fluorine or silicone oil components, both the hydrophilization of the surface and the maintenance or improvement of the transfer rate can be seen remarkably, and these effects can be obtained continuously once further processed. Such a trend is obvious. From these facts, at least a part of the rubber component, filler component, and oil component of the surface layer is hydrophilized by a chemical action (introduction of a hydrophilic surface group), which is the effect of plasma processing generally called. In addition, it is presumed that the rubber structure is partially destroyed by physical action (surface roughening) and the surface movement of the oil component is promoted. Furthermore, by adding a surfactant, the surfactant is adsorbed on the surface that has been in a high energy state by the plasma treatment, and a hydrophilic group is introduced to the surface, resulting in a more stable hydrophilic surface, which is extremely long. It is estimated that the hydrophilicity lasts for a period. In fact, the shorter the time interval from plasma treatment to application of the surfactant, the higher the effect and the higher the correlation with the plasma deactivation time.
[0043]
Note that the surface-modified intermediate transfer member can be subjected to a treatment in the next step after the excess surfactant is generally removed by means such as washing with water. For the image forming apparatus of FIG. 1, such means can be disposed between the coating device 4 and the coating device 5.
[0044]
As shown in FIG. 1, the surface treatment is performed by providing a plasma processing device 3 and a surfactant coating device 4 in the apparatus, and modifying the surface of the intermediate transfer body 1 at regular intervals or at predetermined intervals. Alternatively, an intermediate transfer member having a surface whose surface is modified in advance without using the plasma processing apparatus 3 may be used. Alternatively, a combination of them, that is, an intermediate transfer body having a surface whose surface has been modified in advance is used, and a plasma processing apparatus 3 and a surfactant coating apparatus 4 are provided alone and in combination in the apparatus. The surface layer 2 may be subjected to additional surface modification treatment at a proper interval so as to compensate for the surface modification effect according to the number of printing processes.
[0045]
2.2 Step (b)
This is a step of forming an image on an intermediate transfer member using an ink jet recording unit. As described above, since the surface of the intermediate transfer member is sufficiently hydrophilic prior to this step, it is possible to form an image without ink being repelled even when performing ink jet recording using water-based ink. is there.
[0046]
However, when high-speed recording is performed, if the next ink droplet comes in contact before the ink droplet previously applied on the intermediate transfer member is sufficiently dried, beading or bleeding occurs, and the image is disturbed. In order to prevent these problems, it is effective to apply in advance an ink viscosity increasing component for reducing the fluidity of the ink on the intermediate transfer member.
[0047]
When the apparatus illustrated in FIG. 1 is used, the ink thickening component is applied by the coating apparatus 5. Here, increasing the viscosity of the ink means that a color material or a resin, which is a part of the composition constituting the ink, reacts chemically with the ink when it comes into contact with the ink, or is physically adsorbed. In addition to the case where an increase in the viscosity of the ink is recognized, the case where the viscosity is locally increased by aggregation of the solid content of the ink composition is included.
[0048]
It is strongly desirable that the ink viscosity increasing component used in the step (b) is appropriately selected depending on the type of ink used for image formation. For example, it is effective to use a polymer flocculant for dye-based inks, and it is effective to use metal ions for pigment-based inks in which fine particles are dispersed. In addition, when using a combination of metal ions as an ink thickening component for a dye-based ink, a pigment component having the same color as the dye component is mixed in the ink, or a white or transparent color that has little effect on the color. These fine particles may be mixed, or a water-soluble resin that reacts with metal ions may be added.
[0049]
Examples of the polymer flocculant used as the ink thickening component include a cationic polymer flocculant, an anionic polymer flocculant, a nonionic polymer flocculant, and an amphoteric polymer flocculant. . Moreover, as a metal ion, for example, Ca²⁺, Cu²⁺, Ni²⁺, Mg²⁺And Zn²⁺Divalent metal ions such as Fe,³⁺And Al³⁺And trivalent metal ions. And when apply | coating these ions, applying as metal salt aqueous solution is desirable. As anions of metal salts, Cl⁻, NO₃ ⁻, SO₄ ^2-, I⁻, Br⁻, ClO₃ ⁻, RCOO⁻(R is an alkyl group).
[0050]
The coating amount of the ink thickening component should be small in terms of the flow of ink image and the drying property, but in terms of reactivity, the total charge number of metal ions is the total charge number of opposite polarity ions in the colored ink. It is desirable to be at least twice as large. For this purpose, a metal salt having a concentration of about 10% by mass of the metal salts listed above may be used, and the coating layer functions sufficiently even if it is thin.
[0051]
As the coating means, FIG. 1 illustrates a roll coater-type coating apparatus 5 as a preferred one, but is not limited to this, and for example, a spray coater can also be used. In addition, a recording head or the like that discharges a liquid having a high viscosity component by an inkjet method can be used. In some cases, it is better to add a drying step after application of the ink thickening component, and then apply the ink after sufficient drying. In such a case, the ink is dried between the coating device 5 and the inkjet recording unit 6. What is necessary is just to add a means.
[0052]
In order to improve the fastness of the finally formed image, a water-soluble resin or a water-soluble crosslinking agent can be added. The material to be used is not limited as long as it can coexist with the ink thickening component. As the water-soluble resin, PVA, PVP or the like is preferably used particularly when a highly reactive metal salt is used as the ink viscosity increasing component. As the water-soluble crosslinking agent, oxazoline or carbodiimide that reacts with a carboxylic acid that is preferably used for dispersing a coloring material in ink is preferably used.
[0053]
Alysine or the like is a material that can relatively achieve both high ink viscosity and image fastness.
[0054]
In addition, in order to uniformly apply the ink thickening component, a surfactant is added to the ink thickening component, or the surfactant is applied by the coating device 4 before the ink thickening component is applied. It is also effective to do.
[0055]
The ink jet recording unit used for image formation is not particularly limited with respect to its ink ejection method and form. In addition to the continuous method, it is also possible to use a device that ejects ink by an on-demand method using an electrothermal conversion element (heating element), an electromechanical conversion element (piezo element), or the like. Further, as the form of the ink jet recording unit, for example, with respect to the configuration of FIG. 1, an ink jet head in the form of a line head in which ink discharge ports are arranged in the axial direction of the intermediate transfer body 1 (direction orthogonal to the drawing) is used. Can be. Further, a head in which ejection openings are arranged in a predetermined range in the tangent or circumferential direction of the intermediate transfer body 1 may be used, and recording may be performed while scanning the head in the axial direction. Furthermore, the number of heads corresponding to the color of the ink used for image formation can be used.
[0056]
The ink used for image formation is not particularly limited, and a water-based ink having a general dye or pigment as an ink coloring material and an aqueous liquid medium for dissolving and / or dispersing the ink is used. Can do. In particular, the pigment ink is suitable because a recorded image with good fastness can be obtained.
[0057]
Examples of the dye include C.I. I Direct Blue 6, 8, 22, 34, 70, 71, 76, 78, 86, 142, 199, C.I. I Acid Blue 9, 22, 40, 59, 93, 102, 104, 117, 120, 167, 229, C.I. I Direct Red 1, 4, 17, 28, 83, 227, C.I. I Acid Red 1, 4, 8, 13, 14, 15, 18, 21, 26, 35, 37, 249, 257, 289, C.I. I Direct Yellow 12, 24, 26, 86, 98, 132, 142, C.I. I Acid Yellow 1, 3, 4, 7, 11, 12, 13, 14, 19, 23, 25, 34, 44, 71, C.I. I Food Black 1, 2, C.I. I acid black 2, 7, 24, 26, 31, 52, 112, 118 and the like. Examples of the pigment include C.I. Pigment Blue 1, 2, 3, 15: 3, 16, 22, C.I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 112, 122, C.I. I pigment yellow 1, 2, 3, 13, 16, 83, carbon black No 2300, 900, 33, 40, 52, MA7, 8, MCF88 (manufactured by Mitsubishi Kasei), RAVEN 1255 (manufactured by Colombia), REGAL 330R, 660R, MOGUL ( Cabot), Color Black FW1, FW18, S170, S150, Printex35 (Degussa), and the like.
[0058]
These pigments are not limited in form, and for example, any of self-dispersion type, resin dispersion type, microcapsule type and the like can be used. As the pigment dispersant used in this case, a water-soluble dispersion resin having a weight average molecular weight of about 1,000 to 15,000 can be preferably used. Specifically, for example, vinyl water-soluble resins, styrene and derivatives thereof, vinyl naphthalene and derivatives thereof, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, acrylic acid and derivatives thereof, maleic acid and derivatives thereof Derivatives, itaconic acid and its derivatives, block copolymers or random copolymers composed of fumaric acid and its derivatives, salts thereof, and the like can be mentioned.
[0059]
In order to improve the fastness of the finally formed image, a water-soluble resin or a water-soluble crosslinking agent can be added. The material used is not limited as long as it can coexist with the ink component. As the water-soluble resin, it is preferable to further add the above-described dispersion resin or the like. As the water-soluble crosslinking agent, oxazoline or carbodiimide having a low reactivity is preferably used in terms of ink stability.
[0060]
An organic solvent can be contained in the aqueous liquid medium constituting the ink together with the above-described color material, and the amount of the organic solvent is a factor that determines the physical properties of the ink after the increase in viscosity. In the system using the intermediate transfer member according to the present invention, the ink for transferring to the recording medium is almost only the color material and the high-boiling organic solvent, and therefore, the optimum value is designed. The organic solvent to be used is preferably a water-soluble material having a high boiling point and a low vapor pressure as described below.
[0061]
For example, polyethylene glycol, polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, thiodiglycol, hexylene glycol, diethylene glycol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, glycerin, etc., and these Two or more kinds selected from among them can be mixed and used. Also, alcohols such as ethyl alcohol and isopropyl alcohol and surfactants can be added to the ink as components for adjusting viscosity, surface tension, and the like.
[0062]
The blending ratio of the components constituting the ink is not limited, and can be appropriately prepared within a dischargeable range from the discharge force, nozzle diameter, and the like of the selected inkjet head. In general, it is possible to use ink in which the color material is 0.1 to 10%, the solvent is 5 to 40%, the surfactant is 0.01 to 5% or less, and the remainder is adjusted with pure water on a mass basis.
[0063]
2.3 Step (c)
In this process, the ink image formed on the intermediate transfer body 1 is transferred to a recording medium 10 that can be in the form of continuous paper such as roll paper or fanfold paper, in addition to a cut sheet. The recording medium 10 contacts the image forming surface of the intermediate transfer member 1 by the pressure roller 11 and receives ink. According to the present embodiment, at this stage, the water in the ink is evaporated on the intermediate transfer body 1 and the viscosity thereof is increased, so that a good image can be formed on a recording medium with a small amount of ink absorption. it can.
[0064]
However, if the time from the formation of the ink image in step (b) to the transfer in step (c) is extremely short, the amount of water in the ink may not fall to the amount of water allowed by the recording medium by natural evaporation. It is done. In consideration of such a case, in the image forming apparatus of FIG. 1, the moisture removal promoting device 8 in the form of a blower (which may blow warm air) may be provided between the position where ink image formation is performed and the position where transfer is performed. To remove water in the ink. As other means for promoting moisture removal, for example, heating from the ink image forming surface side may be used, or a heating roller 9 that performs heating by contacting the back surface side of the hollow intermediate transfer body 1 may be used. it can.
[0065]
Further, the recording medium on which the image is recorded through the intermediate transfer member as described above has excellent surface smoothness by being pressed by the fixing roller 12. In addition, by using the fixing roller 12 that heats the printed matter, the printed matter can be instantly fastened.
[0066]
In the apparatus illustrated in FIG. 1, the intermediate transfer member after the ink image has been transferred is further cleaned by the cleaning unit 13 disposed in the next stage in preparation for receiving the next image. As the means for performing the cleaning, use a means for performing water cleaning or wiping while applying water in the form of a shower, direct cleaning such as contact with the water surface, or wiping such as bringing a wet Molton roller into contact with the surface. Is desirable. Of course, it is also effective to use these in combination.
[0067]
Further, if necessary, it is also effective to dry the surface of the intermediate transfer member by bringing a dry Molton roller into contact with it after washing or by blowing air. Depending on the ink used, it is also effective to perform cleaning using components that are blended for the purpose of improving wettability. In this case, the coating device 4 for applying the wettability improving component described above is also used as a cleaning unit.
[0068]
2.4 Effects of the embodiment
As described above, each step or means for carrying out has been described in detail. The technical feature of the embodiment of the present invention is that an image is obtained by subjecting an intermediate transfer body having a fluorine or silicone compound that can obtain a high transfer rate to hydrophilic treatment. The point that the formability is improved and the image formation on the intermediate transfer member is performed by the ink jet recording method. The main effects obtained by realizing a high transfer rate are a reduction in the amount of ink applied to the intermediate transfer member and an improvement in cleaning properties.
[0069]
First, the following three points can be given as merits obtained by reducing the ink amount.
(1) Reduction of bleeding and beading
Both bleeding and beading are caused by contact between ink droplets. Therefore, the contact of ink droplets can be reduced by reducing the amount of ink supplied onto the intermediate transfer member.
(2) Reduction of moisture volatilization
In order to increase the transfer efficiency, it is strongly desirable to increase the internal cohesive force of the ink. However, since ink for ink jet recording generally contains a large amount of moisture, this can be realized by removing this moisture. . At this time, the smaller the amount of ink per unit surface area on the intermediate transfer body, the quicker and easier it is to remove water.
(3) Reduction of dot gain during transfer
The more ink on the intermediate transfer body, the more the dots are crushed by the pressure at the time of transfer, causing the diameter to widen and reducing the resolution, but this can be prevented by reducing the amount of ink.
[0070]
Furthermore, the following two points can be given as merits obtained by improving the cleaning property.
(1) Response to different image output
In particular, when outputting different images one by one, the surface of the intermediate transfer member should be cleaned prior to image formation. The less residual ink on the surface of the intermediate transfer body after transfer, the easier the cleaning.
(2) Improvement of ink usage efficiency
If the amount of ink discarded by cleaning is reduced, not only the use efficiency of ink is increased and the running cost can be lowered, but also the amount of waste can be reduced.
[0071]
As described above, by combining the intermediate transfer member having a high cleaning property and the ink jet recording apparatus which is a digital image recording unit, even a different image can be output with high quality.
[0072]
In addition, the ink jet recording method can use ink with very little solid content, and has the possibility of forming an image without sacrificing its texture on a recording medium, particularly paper. In order to make use of this possibility, the surface of the intermediate transfer member is made hydrophilic, so that it is possible to form a thin layer uniformly without causing the water-based ink and the ink viscosity increasing component to be repelled. As a result, not only the image quality is improved, but also the water removal can be accelerated by spreading the ink thinly, so that a synergistic effect that can cope with high-speed image recording is also produced.
[0073]
By the way, a surface containing a fluorine compound or a silicone compound is generally a water-repellent surface and repels a liquid such as ink unless it is subjected to any treatment, making it difficult to hold and form an image. In the present invention or embodiment, the reason for performing the surface modification by the plasma treatment and the surfactant application treatment is to eliminate this problem, that is, it is possible to hold and form an ink image on a surface with high ink transfer efficiency. Because. The intermediate transfer body having a surface containing a fluorine compound or a silicone compound having a high ink transfer efficiency is subjected to a surface modification treatment by a plasma treatment and a surfactant application treatment, so that the original high ink transfer efficiency can be obtained. The surface of the intermediate transfer member can be made suitable for ink holding while being kept.
[0074]
Further, by applying an ink viscosity increasing component on the intermediate transfer body prior to ink image formation, image deterioration is prevented even during high speed image formation in which a large amount of ink is applied within a short time. That is, by reducing the fluidity of the ink, the occurrence of beading or bleeding is suppressed even if the ink droplets come into contact with each other. Regardless of how the transfer efficiency is increased, it is difficult to prevent adjacent ink droplets from coming into contact in so-called “solid” image formation. In contrast, the polymer flocculant and the aqueous metal ion solution previously mentioned as examples of the ink viscosity increasing component can immediately aggregate the ink and reduce the fluidity of the ink.
[0075]
However, it is not easy to uniformly apply the ink thickening component to the releasable surface. Of course, only the ink thickening component causes repelling on the surface of the intermediate transfer member, and when a wettability improver is added, a large amount of addition is required. Then, the coating film becomes thick, and the above-described advantage of reducing the ink amount is diminished. For this reason, it is very effective to apply the ink thickening component after the intermediate transfer member is sufficiently hydrophilicized by plasma treatment and surface modification by applying a surfactant.
[0076]
In addition, no matter how much surface modification can be performed to form an ink image, it is difficult to apply ink to the releasable surface by a contact method. Therefore, the object of the present invention can be achieved by using, as the image forming means, an ink jet system capable of applying ink without contact.
[0077]
3. Specific examples
Next, some examples will be given, and each recording mode will be specifically described along each step. In the following description, “parts” and “%” are based on mass unless otherwise specified.
[0078]
(3.1) Example 1
(A) Surface modification of transfer body
In this example, an aluminum drum coated with a silicone rubber having a rubber hardness of 40 ° (KE12 manufactured by Shin-Etsu Chemical Co., Ltd.) to a thickness of 0.2 mm was used as the intermediate transfer member. First, the surface of the intermediate transfer member was subjected to surface modification under the following conditions using an atmospheric pressure plasma processing apparatus 3 (ST-7000 manufactured by Keyence Corporation).
Processing distance: 5mm
Plasma mode: High
Processing speed: 100 mm / sec
[0079]
Subsequently, a commercially available neutral detergent composed of sodium alkylbenzenesulfonate was immersed in a surfactant aqueous solution diluted with pure water to 3%, washed with water and dried.
[0080]
(B) Image formation on intermediate transfer member
Next, a 5% by mass aqueous solution of a polymer flocculant (C577S manufactured by Mitsui Cytec Co., Ltd.) was applied to the surface of the intermediate transfer member with a roll coater, and then an inkjet recording part (nozzle density 1200 dpi (dot / inch; reference value)), A character image that was mirror-reversed using water-based ink was formed on the intermediate transfer member at an ejection amount of 4 pl and a driving frequency of 12 kHz. Here, ink having the following composition was used. At this time, beading did not occur when the recorded image was formed on the intermediate transfer member.
・ The following dyes: 4 parts
Black: CI. Food black 2
・ Glycerin: 10 parts
・ Diethylene glycol: 5 parts
・ Surfactant (made by Kawaken Fine Chemicals)
Acetylenol EH): 1 part
・ Ion exchange water: 80 parts
[0081]
(C) Transcription
The intermediate transfer body after the above series of steps is brought into contact with the surface-coated printing paper with a low ink absorbency (Npi Coat A size 40.5 kg made by Nippon Paper Industries Co., Ltd.) with a pressure roller. The recorded image was transferred. At this time, no beading was seen in the image on the printing paper, and good character quality was obtained. Further, there was almost no residual ink on the surface of the intermediate transfer member after transfer, and no adverse effect was observed even if the next image was received as it was.
[0082]
(3.2) Example 2
(A) Surface modification of transfer body
As an intermediate transfer member, an aluminum drum coated with a silicone rubber having a rubber hardness of 60 ° (KE30 manufactured by Shin-Etsu Chemical Co., Ltd.) with a thickness of 0.2 mm was used. First, the surface of the intermediate transfer member was subjected to surface modification under the following conditions using an atmospheric pressure plasma processing apparatus (Plasma Atom Handy manufactured by Nippon Paint Co., Ltd.).
Processing distance: 1mm
Plasma mode: Standard
Processing speed: 10 mm / sec
[0083]
Subsequently, a surfactant aqueous solution obtained by diluting a silicone surfactant (silwet L-77 manufactured by Nihon Unicar Co., Ltd.) with pure water so as to be 1% was spray-coated, washed with water after 10 seconds, and dried.
[0084]
(B) Image formation on intermediate transfer member
Next, a roll coater is applied to the surface of the intermediate transfer member in which 0.5% of a fluorosurfactant (Surflon S-141 manufactured by Seimi Chemical Co., Ltd.) is added to a 10% by mass aqueous solution of calcium chloride dihydrate. Then, a character image was formed by mirror inversion using four colors of ink in an ink jet recording section (nozzle density 1200 dpi, ejection amount 4 pl, driving frequency 10 kHz). Here, inks having the following compositions were used. At this time, beading and bleeding did not occur when the recorded image was formed on the intermediate transfer member.
・ Each pigment below: 3 parts
Black: Carbon black (MCF88 manufactured by Mitsubishi Chemical)
Cyan: Pigment Blue 15
Magenta: Pigment Red 7
Yellow: Pigment Yellow 74
・ Styrene-acrylic acid-ethyl acrylate copolymer
(Acid value 240, weight average molecular weight 5000): 1 part
・ Glycerin: 10 parts
・ Ethylene glycol: 5 parts
・ Surfactant (made by Kawaken Fine Chemicals)
Acetylenol EH): 1 part
・ Ion exchange water: 80 parts
[0085]
(C) Transcription
First, the air was blown to the surface of the recording image on the intermediate transfer member by a blower installed between the ink jet recording unit and the pressure roller. Thereafter, this intermediate transfer member was contacted with a surface-coated printing paper having a low ink absorbability (NPi Coat, ANP, 40.5 kg, manufactured by Nippon Paper Industries Co., Ltd.) with a pressure roller to transfer the recorded image. As a result, no beading or bleeding was observed in the image on the printing paper, and good image quality was obtained.
[0086]
(3.3) Example 3
Hereinafter, the image recording method of this embodiment will be described step by step.
[0087]
(A) Surface modification of transfer body
In this example, as the intermediate transfer member surface layer, a 0.2 mm thick aluminum plate coated with fluoro rubber (Asahi Glass Aflas 150C) with a thickness of 0.5 mm was used. First, the surface of the intermediate transfer member was subjected to surface modification under the following conditions using an atmospheric pressure plasma processing apparatus (AP-T02 manufactured by Sekisui Chemical Co., Ltd.).
Processing distance: 2mm
Input voltage: 240V
Frequency: 10kHz
Introduced gas: wet AIR
Processing speed: 30 sec
[0088]
Subsequently, an aqueous surfactant solution diluted with pure water so as to be 5% of a commercially available surfactant based on alkyl sulfate ester was applied with a sponge roller, washed with water after 60 seconds, and dried.
[0089]
Subsequently, the intermediate transfer member surface layer was applied to an aluminum drum as a support to obtain an intermediate transfer member.
[0090]
(B) Image formation on intermediate transfer member
Next, a fluorine-based surfactant (Surflon S-141 manufactured by Seimi Chemical Co., Ltd.) was applied to the surface of the intermediate transfer member with a roll coater.
[0091]
Next, a 10% by mass aqueous solution of aluminum chloride hexahydrate was applied with a roll coater, and then ink of four colors was used in an ink jet recording unit (nozzle density 1200 dpi, discharge amount 4 pl, drive frequency 8 kHz). As a result, a mirrored mirror image was formed. Here, the ink used in Example 2 was used as the ink. At this time, beading and bleeding did not occur when the recorded image was formed on the intermediate transfer member.
[0092]
(C) Transcription
First, the ink image on the intermediate transfer member was heated by a heating roller (surface temperature 60 ° C.) installed at a position in contact with the back surface of the intermediate transfer member to accelerate the evaporation of moisture. Thereafter, the intermediate transfer member was contacted with a surface-coated printing paper having a low ink absorbability (Npi Coat A size 40.5 kg made by Nippon Paper Industries Co., Ltd.) with a pressure roller to transfer the recorded image. As a result, no beading was observed in the image on the printing paper, and good image quality was obtained.
[0093]
Next, the residual ink slightly remaining on the intermediate transfer member was removed by contacting with a wet Molton roller. At this time, the residual ink could be easily removed.
[0094]
(3.4) Example 4
(A) Surface modification of transfer body
In this example, as an intermediate transfer member, a polyester film having a thickness of 0.5 mm was subjected to a base treatment with a silane coupling agent (KBM503 manufactured by Shin-Etsu Chemical), and then a fluorosilicone rubber having a rubber hardness of 60 ° (FE361 manufactured by Shin-Etsu Chemical). -U) was coated with a thickness of 0.2 mm to form an intermediate transfer member surface layer. The intermediate transfer member surface layer was subjected to surface modification using a parallel plate plasma processing apparatus under the following conditions.
Gas used: 5mm
Gas flow rate: 100sccm (standard cc / min)
Pressure: 0.08 torr (1.066 Pa)
Power: 1200W
Processing time: 30 sec
[0095]
Subsequently, a surfactant aqueous solution obtained by diluting a fluorine-based surfactant (Surflon S-141 manufactured by Seimi Chemical Co., Ltd.) with pure water so as to be 10% was applied with a sponge roller, washed with water after 60 seconds, and dried.
[0096]
Subsequently, the intermediate transfer member surface layer was applied to an aluminum drum as a support to obtain an intermediate transfer member.
[0097]
(B) Image formation on intermediate transfer member
A character image that is mirror-reversed using four colors of ink on an intermediate transfer body on which an ink thickening component is applied on the surface in an ink jet recording section (nozzle density 1200 dpi, ejection amount 4 pl, drive frequency 5 kHz). Formed. Here, the ink used in Example 2 was used. At this time, beading and bleeding did not occur when the recorded image was formed on the intermediate transfer member.
[0098]
(C) Transcription
First, the air was blown to the surface of the recording image on the intermediate transfer member by a blower installed between the ink jet recording unit and the pressure roller. Thereafter, the intermediate transfer member was contacted with a surface-coated printing paper with a low ink absorbability (Npi Coat A size 40.5 kg made by Nippon Paper Industries Co., Ltd.) with a pressure roller to transfer the recorded image. As a result, no beading or bleeding was observed in the image on the printing paper, and good image quality was obtained.
[0099]
Further, the intermediate transfer member used in this example showed good image forming properties even after being stored for 6 months.
[0100]
4). Example of control system and control procedure
In the case where the image forming apparatus of FIG. 1 is configured using the respective units employed in the first to third embodiments, the control system can be configured as described below.
[0101]
FIG. 2 is an example of a control system that can be configured corresponding to the image forming apparatus of FIG. In the image forming apparatus denoted as a whole by reference numeral 100, reference numeral 101 denotes a CPU which forms a main control unit of the entire system, and controls each unit. A memory 103 includes a ROM that stores a basic program of the CPU 101 and a RAM that is used for temporary storage of various data, processing of image data, and other work. Reference numeral 117 denotes an interface for exchanging information such as data and commands with the image supply apparatus 150 which is an image data supply source that allows a host computer or other forms.
[0102]
Reference numeral 110 denotes a drive unit for rotationally driving the intermediate transfer member 1 in the above steps (a) to (c). Reference numeral 115 denotes a conveyance system for the recording medium 10, which includes a driving unit for the pressure roller 11 and the fixing roller 12. Reference numeral 120 denotes a bus line. In addition to the above-described parts, for example, an atmospheric pressure plasma processing apparatus 3, a coating apparatus 4, a coating apparatus 5, an ink jet recording section 6, and a moisture removal promoting apparatus that can take any of the above-described embodiments. 8. The heating roller 9 and the cleaning unit 13 are connected and a control signal of the CPU 101 is transmitted. In addition, a state detection sensor is provided in each part to be controlled, and the detection signal can be transmitted to the CPU 101 via the bus line 120.
[0103]
FIG. 3 is a flowchart showing an example of an image forming process procedure using such a control system.
[0104]
When image data is transmitted from the image supply device 150 and recording is instructed, first, the image processing is performed on the image data in the inkjet recording unit 6 to perform image formation (step S1). If the image supply device does not send data that has been mirror-inverted in advance, this inversion processing can be included in this image processing process.
[0105]
When the inkjet recording unit 6 is ready to perform image formation, the intermediate transfer body 1 is rotated (step S3), and the atmospheric pressure plasma processing apparatus 3 and the coating apparatus 4 related to the step (a) for performing surface modification. Driving (step S5), driving of the coating apparatus and ink jet recording unit 6 related to the step (b) of forming an image on the intermediate transfer body 1 (step S7), and step of transferring to the recording medium (c) The water removal promotion device 8 and the heating roller 9, the recording medium transport system 115, and the cleaning unit 13 are driven (step S9). At this time, each unit is driven in synchronism so that image formation is performed after the surface modification is performed, and the position where the image formation is performed and the transfer position on the recording medium are aligned. If the inkjet recording unit 6 is of a serial recording type, image formation is performed while alternately repeating main scanning of the inkjet head and rotation of the intermediate transfer body 1 by a predetermined amount. Then, when the processing for the instructed amount of image data is finished, this procedure is finished.
[0106]
In the above procedure, the surface modification is always performed in a series of processing flows, but may be performed at an appropriate timing. That is, it may be performed prior to a series of image formation, and is performed independently of a series of image formation while managing based on time, recording data amount, etc., or monitoring deterioration of the surface of the intermediate transfer member. You may do it. They can also be combined.
[0107]
FIG. 4 shows an example of the surface modification treatment procedure. In accordance with the start of this procedure, the plasma treatment by the atmospheric pressure plasma treatment device 3 (step S31) and the application of the surfactant by the coating device 4 (step S33) are performed. Done. The execution time or the surface modification treatment amount of this procedure can be determined as appropriate. For example, it can be performed over several rotations of the intermediate transfer body 1.
[0108]
In the surface modification treatment, the plasma treatment and the surfactant application do not necessarily have to be performed as a pair, and can be appropriately selected and performed. For example, after both are performed, if only one of the processes is performed and a sufficient effect can be maintained, only one of them may be selectively performed.
[0109]
5. Other
The present invention does not necessarily require that steps (a) to (c) are performed in a series of processes, or that all the execution means corresponding to each step are provided in an integrated apparatus. . That is, for example, as described in connection with Example 4, if the intermediate transfer body subjected to the surface modification treatment can maintain its performance for a long time, the process (b) ) And (c), or an image forming apparatus provided with means for executing these steps is also included in the scope of the present invention. That is, it is sufficient that the intermediate transfer member is preferably surface-modified prior to image formation on the intermediate transfer member, and the step of performing such surface modification is always performed immediately before image formation on the intermediate transfer member. It does not have to be performed. Further, the surface modifying means is not necessarily provided in the image forming apparatus. That is, the intermediate transfer member may be detachable from the installation means provided in the image forming apparatus, and the intermediate transfer body subjected to surface modification is attached to the apparatus by the installation means and used. Various forms are also included in the present invention. Furthermore, the present invention also resides in a method for modifying the surface of an intermediate transfer member and the intermediate transfer member, which are suitable for executing the image forming method in which the steps (b) and (c) are performed.
[0110]
Embodiments of the present invention are listed below.
[0111]
[Embodiment 1] A step of subjecting an intermediate transfer body having a surface made of at least one of a fluorine compound or a silicone compound to a surface modification treatment by plasma treatment and surfactant application treatment;
Forming an image by ejecting ink onto an intermediate transfer member having a surface subjected to the modification treatment;
Transferring the image of the ink formed on the intermediate transfer member to a recording medium;
An image forming method comprising:
[0112]
[Embodiment 2] The image forming method according to Embodiment 1, wherein the plasma treatment is performed under atmospheric pressure or reduced pressure.
[0113]
[Embodiment 3] The image forming method according to Embodiment 1 or 2, wherein the intermediate transfer member has a surface layer formed of an elastic body having a rubber hardness in the range of 10 to 100 °.
[0114]
[Embodiment 4] The method according to any one of Embodiments 1 to 3, further comprising a step of imparting a component for increasing the viscosity of the ink to the surface prior to forming the image of the ink. Image forming method.
[0115]
[Embodiment 5] The image forming method according to Embodiment 4, wherein the component for increasing the viscosity of the ink is an aqueous solution containing at least metal ions.
[0116]
[Embodiment 6] The image forming method according to any one of Embodiments 1 to 5, wherein the ink is an aqueous ink containing a fine particle dispersion.
[0117]
[Embodiment 7] The image according to any one of Embodiments 1 to 6, further comprising a step of accelerating the removal of water in the ink prior to transferring the image of the ink to the recording medium. Forming method.
[0118]
[Embodiment 8] The image forming method according to Embodiment 7, wherein at least one of blowing and heating is performed in the moisture removal promoting step.
[0119]
[Embodiment 9] The image forming method according to any one of Embodiments 1 to 8, wherein the transfer is performed with relative pressurization of the recording medium to the intermediate transfer member.
[0120]
[Embodiment 10] The method includes the step of cleaning the surface at least one of after the transfer step, before the surface modification step, and after the surface modification step. The image forming method according to any one of Embodiments 1 to 9.
[0121]
[Embodiment 11] A step of preparing an intermediate transfer body having a surface containing at least one material of fluorine rubber or silicone rubber and subjected to the surface modification treatment by plasma treatment and surfactant application treatment. When,
Forming an image on the intermediate transfer member by ejecting ink using an inkjet recording means;
Transferring the image of the ink formed on the intermediate transfer member to a recording medium;
An image forming method comprising:
[0122]
[Embodiment 12] An image forming apparatus using an intermediate transfer member having a surface made of at least one of a fluorine compound and a silicone compound,
Means for subjecting the intermediate transfer member to surface modification treatment by plasma treatment and surfactant application treatment;
Means for forming an image by ejecting ink onto an intermediate transfer member having a surface subjected to the modification treatment;
Means for transferring an image of the ink formed on the intermediate transfer member to a recording medium;
An image forming apparatus comprising:
[0123]
[Embodiment 13] Installation for installing an intermediate transfer member having a surface containing at least one material of fluorine rubber or silicone rubber and subjected to the surface modification treatment by plasma treatment and surfactant application treatment Means,
Means for forming an image by ejecting ink to the intermediate transfer member installed in the installation means using an inkjet recording means;
Means for transferring an image of the ink formed on the intermediate transfer member to a recording medium;
An image forming apparatus comprising:
[0124]
[Embodiment 14] An intermediate having a surface made of at least one of a fluorine compound and a silicone compound, an ink image is formed on the surface, and the formed ink image is transferred to a recording medium. A method for modifying the surface of an intermediate transfer member, wherein the surface of the transfer member is subjected to a surface modification treatment by applying a plasma treatment and a surfactant.
[0125]
[Embodiment 15] An intermediate having a surface made of at least one of a fluorine compound and a silicone compound, an ink image is formed on the surface, and used to transfer the formed ink image to a recording medium An intermediate transfer member, wherein the transfer member is subjected to a surface treatment by plasma treatment and application of a surfactant.
[0126]
【The invention's effect】
As described above, according to the present invention, there is provided an image forming method in which the number of recording media is small and different digital images can be output for each sheet. Further, it becomes possible to produce a small number of printed matter with high quality and low cost even on a glossy recording medium.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating an example of a control system that can be configured corresponding to the image forming apparatus of FIG.
FIG. 3 is a flowchart illustrating an example of an image forming process procedure using the control system of FIG. 2;
4 is a flowchart showing an example of a surface modification process procedure of an intermediate transfer member that can be executed by the control system of FIG. 2;
[Explanation of symbols]
1 Intermediate transfer member
2 Ink-repellent surface layer
3 Atmospheric pressure plasma processing equipment
4 Coating device
5 Coating device
6 Inkjet recording unit
7 Ink dots
8 Moisture removal promotion device
9 Heating roller
10 Recording media
11 Pressure roller
12 Fixing roller
13 Cleaning unit
100 Image forming apparatus
101 CPU
110 Intermediate transfer member driving unit
115 Recording medium transport system

Claims (12)

A step of subjecting the intermediate transfer member to a plasma treatment and a surfactant treatment;
Applying a liquid for reducing the fluidity of the ink on the intermediate transfer body on the intermediate transfer body subjected to the plasma treatment and the surfactant application treatment;
Forming an image by ejecting ink onto the intermediate transfer body to which the liquid is applied;
Transferring the image formed on the intermediate transfer member to a recording medium;
An image forming method comprising:   The image forming method according to claim 1, wherein the plasma treatment is performed under atmospheric pressure or reduced pressure.   3. The image forming method according to claim 1, wherein the intermediate transfer member has a surface layer formed of an elastic member having a rubber hardness in a range of 10 ° to 100 °.   The image forming method according to claim 1, wherein the liquid includes a component for aggregating the color material of the ink.   The image forming method according to claim 4, wherein the component is a metal ion.   6. The image forming method according to claim 1, further comprising a step of accelerating water removal from the ink prior to transferring the image to the recording medium. 7. The image forming method according to claim 1 , further comprising a step of cleaning the intermediate transfer member. Performing a plasma treatment and a surfactant application treatment on the surface of the intermediate transfer body in order to hydrophilize the surface of the intermediate transfer body having a surface containing at least one material of fluorine rubber or silicone rubber;
A step of applying a liquid that reacts with ink on the intermediate transfer body subjected to the plasma treatment and the surfactant application treatment;
Forming an image by ejecting ink onto the intermediate transfer member to which the liquid is applied using an inkjet recording means;
Transferring the image formed on the intermediate transfer member to a recording medium;
An image forming method comprising: A step of applying a liquid that reacts with the ink on the intermediate transfer body subjected to the plasma treatment and the surfactant application treatment;
Forming an image by ejecting ink onto the intermediate transfer body provided with the liquid using an ink jet recording means;
Transferring the image formed on the intermediate transfer member to a recording medium;
An image forming method comprising: The fluidity of the ink on the intermediate transfer member having a surface containing at least one material of fluorine rubber or silicone rubber, which has been subjected to a plasma treatment and a surfactant application treatment. Applying a liquid for lowering,
Forming an image by ejecting ink onto the intermediate transfer body provided with the liquid using an ink jet recording means;
Transferring the image formed on the intermediate transfer member to a recording medium;
An image forming method comprising: Means for applying a liquid for reducing the fluidity of the ink on the intermediate transfer body on the intermediate transfer body subjected to the plasma treatment and the surfactant application treatment;
Means for forming an image by ejecting ink onto the intermediate transfer member provided with the liquid;
A transfer portion for transferring an image formed on the intermediate transfer member to a recording medium;
An image forming apparatus comprising: Means for applying a liquid that reacts with ink to an intermediate transfer member having a surface containing at least one material of fluorine rubber or silicone rubber, and having been subjected to plasma treatment and surfactant application treatment on the surface When,
Means for forming an image by ejecting ink to the intermediate transfer body provided with the liquid using an ink jet recording means;
A transfer portion for transferring an image formed on the intermediate transfer member to a recording medium;
An image forming apparatus comprising:

Images