JP4006374B2 - Image forming method, image forming apparatus, and recorded product manufacturing method - Google Patents

Description

  The present invention relates to an image forming method and an image forming apparatus using an ink jet recording method, and more particularly to an image forming method which is not easily affected by the ink absorption amount of a recording medium, and an image forming apparatus for realizing the method.

  At present, the mainstream of image formation using paper as a recording medium is offset printing. Since offset printing can produce a high-quality print at high speed, it is suitable for mass production, and the cost per sheet is very low because of mass production. This is because in offset printing, if a single plate is made in the plate making process, a large number of copies can be made based on this, so that the ratio of the plate making cost occupied by each printed matter can be made small. Such offset printing has been very well matched to previous market demands.

  However, in recent years, as the diversification of information and the diversification of printed products have progressed to small lots, there has been a problem that the plate making cost for each printed material increases and becomes expensive. Furthermore, in recent years, the immediacy of information has become more important, and there is an increasing demand for a short delivery time in the market that “I want to get a printed matter immediately”. In response to this requirement, the current offset printing has a long lead time from document preparation to plate making and printing preparation (equipment stabilization), and the actual printing time can be output at around 9000 sheets / min. The current situation is that small lots of copies do not lead to short delivery times. In addition, it requires enormous capital investment, and all process operations require highly skilled skills. Therefore, the number of production bases is limited, and it takes time to reach the customer's hands after printing is completed. It was.

  Due to such changes in market demand, printing using an inkjet recording method has attracted attention in recent years. The ink jet recording method is a method for recording an image pattern on a recording medium in a non-contact manner without using a plate, but is a plateless method and is suitable for printing a small number of copies. Furthermore, since the computerization of information has progressed and image information can be easily operated, it is immediately good without requiring high expertise and without requiring large-scale equipment. Combined with the fact that printed matter can be obtained, the ink jet recording method is an expected information recording method.

  By the way, as a recent trend, there is a demand for recording a high-quality image by an inkjet recording method regardless of the type of recording medium. However, in the case of the ink jet recording method, since it is affected by the ink absorption characteristics of the recording medium, it is difficult to record a high-quality image regardless of the type of the recording medium. It is difficult to record a high-quality image on a non-absorbing recording medium that does not absorb ink at all. When recording on a recording medium with poor ink absorption capability, a phenomenon called bleeding in which adjacent ink droplets mix with each other, or ink that has landed after the previously landed ink is attracted and ink droplets are drawn. In many cases, a phenomenon called beading occurs, which reduces image quality.

  In order to suppress such bleeding and beading, it is effective to lower the fluidity of the ink on the surface of the recording medium. However, in the case of the ink jet recording method, only low-viscosity ink with high fluidity can be discharged in order to satisfy discharge suitability. In other words, in the case of the ink jet recording method, there is a demand for contradictory characteristics such that the ink fluidity at the time of ejection is increased, while the ink fluidity must be decreased on the recording medium.

  In order to satisfy such conflicting requirements at the same time, an ink image is formed on an intermediate transfer member (hereinafter also simply referred to as a transfer member), and the ink image formed on the transfer member is transferred to a desired recording medium. In addition, a method for forming an ink image on a desired recording medium (an image forming method using an intermediate transfer member) has been proposed (see, for example, Patent Document 1, Patent Document 2, Patent Document 3, and the like). In this system, the ink discharged from the ink jet head is once landed on the intermediate transfer member, and the fluidity of the ink is reduced to some extent, and then the ink image whose flow is reduced is transferred from the transfer member to the recording medium.

  In such an image forming system using an intermediate transfer member, in order to improve the quality of an ink image on a recording medium after transfer, the ink image on the intermediate transfer member before transfer must be improved. For this purpose, it is necessary that the ink image retainability on the intermediate transfer member (the degree that the ink does not move from the landing position and remains in place) is high. However, in Patent Documents 1 to 3, ink image retention on the intermediate transfer member is low, and beading or bleeding occurs on the intermediate transfer member, as in the non-absorbent recording medium described above. Therefore, it is a problem to reduce the ink fluidity on the intermediate transfer member.

  Various proposals have been made for the problems of such transfer ink jet. For example, Patent Document 4 proposes a method in which an ink jet head and an ink supply system are heated to discharge hot melt ink onto an intermediate transfer member, thereby reducing the fluidity of the ink together with heat dissipation.

  Further, Patent Document 5 proposes a method of reducing the fluidity of ink on the intermediate transfer member by heating the intermediate transfer member and promoting moisture evaporation of the ink applied to the intermediate transfer member. .

Further, in Patent Document 6, a liquid (reaction liquid) that reacts with ink is applied onto an intermediate transfer member, and ink droplets are landed on the intermediate transfer member to cause the ink and the reaction liquid to react with each other. A method for reducing the fluidity of the ink has been proposed.
US Pat. No. 4,538,156 US Pat. No. 5,099,256 Japanese Patent Application Laid-Open No. 62-92849, etc. JP-A-7-223312 JP-A-5-330035 Japanese Patent No. 2916864

  However, even if any of the methods described in the above documents is used, the ink fluidity on the intermediate transfer member is suppressed to improve the quality of the ink image on the intermediate transfer member, and the ink on the recording medium after the transfer is obtained. A technology that can improve the quality of images has not been realized.

  For example, when a hot melt ink is used as in Patent Document 4, in order to generate ink phase change characteristics (solid-liquid phase change due to heat), an ink containing a very large amount of binder with respect to a color material is used. Inevitably, the amount of ink applied to obtain a desired density increases. As a result, the image quality is deteriorated due to the large ink thickness of the output image. In other words, with this method, the thickness of the adhered ink is so great that the ink image on the recording medium after transfer is uncomfortable, and the ink image on the recording medium after transfer cannot be made high quality. It is. Further, since solid ink is used at a steady temperature, it is necessary to heat and melt the ink in the ink flow path at the time of start-up, and it takes time until image output. Moreover, since it is necessary to maintain this when the apparatus is in operation, enormous energy is required.

  Moreover, beading and bleeding cannot be suppressed only by heating the transfer body as in Patent Document 5. This is because ink beading or bleeding occurs at the moment of ink landing, so that beading or bleeding occurs before the ink fluidity is sufficiently lowered by heating. In this method, only the effect of drying the ink image formed on the transfer body can be obtained, the retention of the ink image on the transfer body is still low, and the ink image on the transfer body is of high quality. In addition, the ink image on the recording medium after transfer cannot be of high quality.

  Further, in Patent Document 6, although the fluidity of the ink image on the intermediate transfer member can be reduced, the ink image on the intermediate transfer member cannot be made high quality. That is, since the reaction solution itself is a liquid, when such a reaction solution is applied onto the intermediate transfer member, beading of the reaction solution occurs on the intermediate transfer member. Then, since the ink is ejected in a state where the beading of the reaction liquid is generated, the ink cannot be held at a regular place, and the ink image on the transfer body is high quality. It doesn't become a thing. In order to suppress beading, it is possible to form a good ink image on the intermediate transfer member by using an intermediate transfer member having a surface excellent in ink absorbability. In addition to being stuck to the recording medium, it becomes impossible to perform good transfer onto a recording medium, and cleaning becomes difficult.

  As is apparent from the above, various methods including a recording medium (for example, a non-absorbing recording medium) having a poor ink absorption capability without being affected by the ink absorption characteristics of the recording medium even if the method using the intermediate transfer member is used. It has not been possible to form a high-quality ink image on a recording medium.

  Accordingly, an object of the present invention is to provide an image forming method capable of recording an image on a wide range of media regardless of the ink absorption characteristics of the recording medium, without sacrificing the high recordability of the inkjet recording method. And providing an image forming apparatus.

In order to achieve the above object, the present invention provides a step of applying a first liquid to the intermediate transfer member for improving the wettability of the surface of the intermediate transfer member, and reduces the fluidity of the ink on the intermediate transfer member. a second liquid for causing the the steps of the first liquid is applied to the intermediate transfer body granted, to an intermediate transfer member the first liquid and the second liquid has been applied, the inkjet Applying the ink from a recording head to form an ink image on the intermediate transfer member; and transferring the ink image formed on the intermediate transfer member to a recording medium. Features.

Further, another present invention, the intermediate transfer member having a non-absorbent surface, and applying a first liquid for improving the wettability of the intermediate transfer member surface, aggregating the coloring material of the ink a second liquid for the the steps of the first liquid is applied to the intermediate transfer body granted, with respect to the first liquid and the intermediate transfer member to which the second liquid has been applied, the ink jet recording Applying the ink from a head to form an ink image on the intermediate transfer member; and transferring the ink image formed on the intermediate transfer member to a recording medium. And

Here, the surface of the intermediate transfer member, Rukoto to have a compound containing at least fluorine or silicone is preferred. Further, it is preferable that the surface of the intermediate transfer member has a rubber hardness in the range of 10 to 100 °. The first liquid is preferably a liquid containing a surfactant. Moreover, it is preferable to change the position where the first liquid is applied in accordance with the image to be formed. The second liquid is preferably a liquid containing metal ions. Moreover, it is preferable to change the position where the second liquid is applied in accordance with the image to be formed. The second liquid preferably contains a surfactant. Further, it is preferable that at least one of the first liquid , the second liquid , and the ink contains a cross-linking agent. It is also preferred to include a step to facilitate removal of the solvent contained in the image of the ink formed on the intermediate transfer member. In addition, it is preferable that at least one of the first liquid and the second liquid is applied using an inkjet head.

In another aspect of the present invention, a step of applying a first liquid containing a surfactant to an intermediate transfer member having a surface containing at least one of fluorine rubber and silicone rubber, and aggregating the ink coloring material A step of applying a second liquid to the intermediate transfer body to which the first liquid is applied, and an intermediate transfer body to which the first liquid and the second liquid are applied from an inkjet recording head Applying the ink to form an ink image on the intermediate transfer member; and transferring the ink image formed on the intermediate transfer member to a recording medium. .

Another aspect of the present invention is an apparatus for forming an image of the ink on the recording medium by transferring an ink image formed on the intermediate transfer body onto the recording medium. First transfer means for applying a first liquid for improving the wettability to the intermediate transfer member, and a second liquid for reducing the fluidity of the ink, an intermediate transfer to which the first liquid is applied. A second applying unit for applying to the body, an ink jet recording head for applying the ink to the intermediate transfer body to which the first liquid and the second liquid are applied, based on image data, and the ink jet recording head. And a transfer unit for transferring the image of the ink applied to the intermediate transfer member from the intermediate transfer member to the recording medium .
Another aspect of the present invention is a method for producing a recorded matter in which an image of ink is formed on a recording medium, wherein the intermediate is provided with a first liquid for improving the wettability of the surface of the intermediate transfer member. For the transcript,
The step of applying a second liquid for aggregating the color material of the ink, and applying the ink from an ink jet recording head to the intermediate transfer body to which the first liquid and the second liquid are applied A step of forming an ink image on the intermediate transfer member, and a step of manufacturing the recorded matter by transferring the ink image formed on the intermediate transfer member to the recording medium. It is characterized by that .

  According to the present invention, image formation that enables image recording on various recording media including recording media (for example, non-absorbing recording media) that have a low ink absorption capability regardless of the ink absorption characteristics of the recording media. A method and an image forming apparatus are provided.

  Hereinafter, the present invention will be described in more detail with reference to embodiments of the present invention.

  First, before detailed description of the present embodiment, features of the present embodiment will be briefly described. The feature of this embodiment is that the second material (image fixing component) that reduces the fluidity of the ink on the intermediate transfer member can be uniformly applied on the intermediate transfer member, or is applied on the intermediate transfer member. In order that the second material can be held at a desired position, the first transfer material (wetability improving component) that improves the wettability of the surface of the intermediate transfer member is added to the intermediate transfer member before the application of the second material. Is to give on. As a result, the image fixing component is not repelled on the surface of the intermediate transfer member and the beading of the image fixing component does not occur, so that the image fixing component can be uniformly applied on the intermediate transfer member, and also applied on the intermediate transfer member. The image fixing component thus made can be held at a desired position. As a result, ink is applied onto the intermediate transfer member in a state where the image fixing component is uniformly applied or in a state where the image fixing component is held at a desired position. The fixed component and the ink react to hold the ink at a desired position on the intermediate transfer member. As a result, the ink image on the intermediate transfer member can be made high quality, and as a result, the ink image on the recording medium after transfer can be made high quality.

  On the other hand, as in Patent Document 6 described above, when a reaction liquid (image fixing component) that reacts with ink is directly applied to the intermediate transfer member, that is, the image is fixed on the intermediate transfer member to which no wettability improving component is applied. When the component is applied, the image fixing component is bounced on the surface of the intermediate transfer member to cause beading of the image fixing component. Therefore, the image fixing component cannot be applied uniformly on the intermediate transfer member, and is also applied on the intermediate transfer member. The image fixing component thus made cannot be held at a desired position. Then, the ink is applied onto the intermediate transfer member in a state where the image fixing component is applied non-uniformly or in a state where the image fixing component exists at a position different from the desired position. The image fixing component and ink react at a position different from the position, and the ink is held at a position different from the desired position. In other words, the ink cannot be held at a desired position on the intermediate transfer member, thereby reducing the quality of the ink image on the intermediate transfer member, and as a result, the ink image on the recording medium after transfer. Cannot be made high-grade.

  Thus, in order to improve the quality of the ink image on the transfer body, it is important to hold the image fixing component that lowers the fluidity of the ink on the intermediate transfer body at a desired position on the intermediate transfer body. For this reason, it is important to add a wettability component before applying an image fixing component.

  Next, an embodiment of the present invention will be described in detail. FIG. 1 shows a schematic diagram of an image forming apparatus of the present invention for realizing an image forming method in an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an intermediate transfer member having a surface layer 2. A coating device 4 for applying an image fixing component, a coating device 3 for applying a wettability improving component, and an inkjet recording device 5 for forming an ink image by ejecting ink droplets from an inkjet recording head. The intermediate transfer body 1 rotates in the direction of the arrow in the figure, and a wettability improving component is first applied to the surface by the coating device 3 and then an image fixing component is applied by the coating device 4. Further, after these components are applied, ink droplets are ejected from the ink jet recording apparatus 5, and an image is formed on the surface of the intermediate transfer member 1. Then, the recording surface of the recording medium 9 is brought into contact by being pressed by the pressure roller 10, and an image is formed on the recording medium 9. In the apparatus illustrated in FIG. 1, a moisture removal accelerating device 7 is arranged, moisture in the ink constituting the image on the intermediate transfer body 1 is removed, and then the image is transferred to the recording surface of the recording medium 9. It has a configuration. Further, the apparatus illustrated in FIG. 1 is configured such that the intermediate transfer member is repeatedly used a plurality of times by cleaning the surface of the intermediate transfer member with the cleaning device 12.

  According to the image recording method in the embodiment of the present invention using the image forming apparatus having the above configuration, there are few restrictions on the types of recording media that can be used, and it is possible to output different images with high quality for each sheet. It becomes. In other words, since the ink is fixed in the normal ink jet recording method by permeation into the recording medium, the image state changes depending on the ink absorption amount of the recording medium, and an image can be formed on the non-absorbing material. There wasn't. On the other hand, the offset printing apparatus is intended to provide a large amount of the same printed matter and cannot output different images for each sheet. The present invention provides an image forming method that simultaneously solves these drawbacks.

  The steps constituting the image forming method in the embodiment of the present invention can be roughly divided into the following four. Hereinafter, a member or an apparatus for performing these steps will be described in detail.

1. Step (a): Step of imparting a wettability improving component on the intermediate transfer member The intermediate transfer member used in this step has a roller shape, a belt shape, a sheet shape (continuous treatment), or a pad shape (batch). Treatment) and the like. In the example shown in FIG. 1, a drum-shaped intermediate transfer body made of a lightweight metal such as an aluminum alloy is selected from the required characteristics such as rigidity and dimensional accuracy that can withstand pressure during transfer and reduction of rotational inertia. .

  The surface layer 2 may have ink permeability (ink absorbability) when the intermediate transfer member is not repeatedly used, but a non-permeable (non-absorbable) material is used when it is repeatedly used. Any material that is permeable but can be cleaned by cleaning can be used repeatedly. However, the penetrable material has a low ink transfer rate, and more ink must be applied onto the intermediate transfer member. Therefore, the cleaning property of the intermediate transfer member can be improved both in terms of material use efficiency and image quality. It cannot be said that it is preferable in terms. The surface layer of the intermediate transfer member is preferably a non-permeable (non-absorbable) material, more preferably a releasable material, from the viewpoint of transfer rate and cleaning properties. Here, the releasability refers to a property in which materials such as ink, image fixing component and wettability improving component are difficult to adhere to the surface and can be peeled later. The higher the releasability, the more advantageous in terms of cleaning load and ink transfer rate, but the lower the critical surface tension of the material, the easier it is to repel even if ink or other liquid adheres, and the image is retained. It is difficult. As a guideline as a suitable releasable material in the present invention, a critical surface tension is 30 mN / m or less, or a contact angle with water is 75 ° or more.

  Specifically, the surface layer 2 can be formed on the surface of the intermediate transfer member 1 by surface treatment such as applying Teflon (registered trademark) processing or silicone oil, but considering the followability to the recording medium. An elastic body is preferable, and the rubber hardness (value measured by rubber hardness tester type A (conforms to JIS K6253)) is preferably in the range of 10 to 100 °. If it is -80 degrees, it can respond to most recording sheets. Specifically, NBR, urethane rubber, chloroprene rubber and those subjected to surface treatment, or fluorine rubber, silicone rubber, or fluorosilicone rubber whose material itself has ink-repellent properties can be suitably used. Moreover, the surface shape of the surface layer 2 is not limited. The recording medium surface shape and printing effect can be selected for selection. For example, if an image such as a general offset print is desired, a smooth surface shape may be selected on a smooth printing paper. On the other hand, when a rough surface or a surface such as a gravure cell is used for a smooth recording medium, it is possible to obtain a printing effect corresponding to the application. In the following text, unless otherwise specified, “intermediate transfer member surface” means “surface of the surface layer on the intermediate transfer member”.

  In the step (a), a wettability improving component is applied on the intermediate transfer member 1 as described above using the coating device 3 (see FIG. 1). Here, the wettability improving component is a material that improves the wettability of the surface of the intermediate transfer member, and a liquid containing a surfactant is preferably used. It plays the role of increasing the surface energy of the surface of the intermediate transfer member and making it difficult to play the subsequently fixed image fixing component.

  The reason for adding the wettability improving component is to uniformly apply the image fixing component on the intermediate transfer member as described above, or to hold the image fixing component at a desired position on the intermediate transfer member. is there. If this step is not performed, the image fixing component beads on the intermediate transfer member, resulting in a non-uniform application state or a state different from a desired position. Even if ink is applied as it is to form an image, a good quality image cannot be obtained. In addition, there is a method of applying an image fixing component to which the wettability improving component is added without performing the step of applying the wettability improving component, but in this case, since the addition amount of the wettability improving component increases, image quality and drying It has an adverse effect on water resistance as well as the properties. In order to minimize the application amount of the wettability improving component and to obtain the desired effect to the maximum, after the surfactant is aligned and oriented on the surface of the intermediate transfer member by applying the wettability improving component alone. It is a more preferable form to add an image fixing component.

  As the wettability improving component, a surfactant can be suitably used. The surfactant that can be used is not particularly limited. For example, the surface used from general cationic surfactants, anionic surfactants, nonionic surfactants, amphoteric surfactants, fluorosurfactants, silicone surfactants, etc. It can be selected depending on the layer. It is also possible to use a mixture of two or more of these materials. Among these, a fluorine-based or silicone-based surfactant is highly effective and is a suitable material. The application amount of the wettability improving component is arbitrary as long as the image fixing component can be applied uniformly. However, from the viewpoint of image stability and drying property, the application amount is preferably small. It is also possible to limit the application area (application position). For example, it is possible to improve the material use efficiency and the drying property by applying only to the image forming area (position where the image fixing component and ink are applied). it can. There is no limitation on the applying means, and a conventionally known technique can be used. Specific examples include a roll coater, a spray coater, and a slit coater. In the case where the application position of the wettability improving component is changed according to the image to be formed, an ink jet head is a suitable application device. Further, the surfactant to be applied can be used even if it is not liquid. For example, the wettability improving component can be imparted by contacting or sliding a solid or waxy surfactant on the surface of the intermediate transfer member.

2. Step (b): Step of applying an image fixing component on the intermediate transfer member In Step (b), an image fixing component is applied by the coating device 4 to the intermediate transfer member to which the wettability component has been applied. Here, image fixing means that (1) when the viscosity of the ink is increased, or (2) a color material or resin that is a part of the composition constituting the ink by contacting with the ink, This includes not only cases where chemical reaction or physical adsorption causes a decrease in the flow characteristics of the ink as a whole, but also includes cases where the flow characteristics are locally reduced by agglomeration of the solid content of the ink composition. It is. That is, the image fixing component is a material for reducing the fluidity of the ink on the intermediate transfer member, and in particular, a liquid that reacts with the ink and aggregates the coloring material in the ink is preferably used.

  The reason for adding the image fixing component is to suppress the fluidity of the ink on the intermediate transfer member as described above so that the ink image can be favorably held on the intermediate transfer member. That is, since the surface of the transfer body to which the wettability improving component is applied is in a state where the ink is more likely to flow, if the image fixing component is not applied, the ink flows and causes defects such as bleeding and beading. Therefore, an image fixing component is applied before ink is applied, and the ink is configured to land on the image fixing component. According to this, since the ink and the image fixing component react at the position where the ink has landed, the ink can be retained at the ink landing position.

  The image fixing component used in step (b) needs to be appropriately selected depending on the type of ink used for image formation. For example, it is effective to use a polymer flocculant for dye ink, and it is effective to use metal ions for pigment (dispersed fine particles) ink. Further, when a metal ion is used in combination as an image fixing component for a dye ink, a pigment having the same color as the dye is mixed in the ink, or white or transparent fine particles having little effect on color are used. It is good to mix.

  In the present invention, examples of the polymer flocculant used as the image fixing component include a cationic polymer flocculant, an anionic polymer flocculant, a nonionic polymer flocculant, and an amphoteric polymer flocculant. Can be mentioned. Examples of metal ions include divalent metal ions such as Ca 2+, Cu 2+, Ni 2+, Mg 2+, and Zn 2+, and trivalent metal ions such as Fe 3+ and Al 3+. And when providing these ions, providing as metal salt aqueous solution is desirable. Examples of the anion of the metal salt include Cl-, NO3-, SO4-, I-, Br-, ClO3-, RCOO- (R is an alkyl group) and the like. In addition, a material having a reversal to the ink used can be used as an image fixing component. For example, if the ink is anionic or alkaline, a cationic or acidic material that is the opposite of the ink can be an image fixing component. These image fixing components may be used in combination of two or more as required.

  In the step (b), the same surfactant as that used in the step (a) or another surfactant is used to fix the image for the purpose of increasing the affinity with the previously formed wettability improving component layer. It is also effective to add to the ingredients. As the application amount of the image fixing component, for example, it is desirable that the total number of charges of the metal ions be equal to or more than the total number of charges of the reverse polarity ions in the colored ink. For this purpose, an aqueous solution having a concentration of about 10% by mass of the metal salts listed above may be used, and the coating layer functions sufficiently with a thin film. As the coating device 4 serving as the applying unit, FIG. 1 illustrates a device using a roll coater, but is not limited thereto. A coating apparatus as described in the above step (a) is preferably used. In addition, it is not essential for the coating state to have a two-layer structure that is completely independent of the wettability-improving component that has been formed previously. Mixing some components in the boundary layer reduces the effect. It will not be a factor.

  In addition, a resin component can be added in order to improve transferability and fastness of the finally formed image. A water-soluble resin or a water-soluble crosslinking agent can also be added. The material used is not limited as long as it can coexist with the image fixing component. In particular, when a highly reactive metal salt is used as an image fixing component, PVA, PVP, or the like is preferably used as the water-soluble resin. 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 an ink is preferably used. Alysine or the like is a material that relatively balances both image fixing and image fastness.

3. Step (c): Step of ejecting ink onto the intermediate transfer member to form an ink image In step (c), the ink jet recording apparatus 5 performs ink jetting on the intermediate transfer member provided with the wettability component and the image fixing component. Ink is ejected from the recording head to form an ink image on the intermediate transfer member. Here, the reason why the ink jet recording head is used as the image forming means is not a plateless system, but it is important that the recording head is technically non-contact recording. This is because even if the image fixing component can be applied uniformly, it is difficult to apply ink to the surface of the transfer body having high releasability by the contact method.

  The inkjet recording method used is not particularly limited, and devices such as a bubble jet (registered trademark) method, a piezo method, and a continuous method can be appropriately selected and used. The ink jet head used can be a line head or a serial head.

  The ink used in the step (c) is not particularly limited, and an aqueous 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. It can be used suitably. Of course, if you only want to obtain a printing effect, it may be colorless. In particular, the pigment ink can obtain a recorded image with good fastness, and can obtain a particularly good image when a metal ion is used as an image fixing component.

  Specific 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 (Mitsubishi Kasei), RAVEN 1255 (Colombia), REGAL 330R, 660R, MOGUL ( Cabot), Color Black FW1, FW18, S170, S150, Printex35 (Degussa), and the like.

  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-based water-soluble resins, styrene and derivatives thereof, vinyl naphthalene and derivatives thereof, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acid, acrylic acid and derivatives thereof, maleic acid and derivatives thereof Derivatives, itaconic acid and derivatives thereof, block copolymers or random copolymers comprising fumaric acid and derivatives thereof, and salts thereof.

  Two or more of these ink materials can be used in combination with each of the dye species, pigment species, dispersion form, and dispersant.

  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.

  An organic solvent can be contained in the aqueous liquid medium that constitutes the ink together with the color material described above, and the amount of the organic solvent is an important factor that determines the physical properties of the ink at the time of image transfer. This is because in the image recording method of the present invention, the ink for transferring from the intermediate transfer member to the recording medium is substantially only the color material and the high boiling point organic solvent. As the organic solvent to be used, the following water-soluble solvents are preferably used.

  Examples include 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, and glycerin. It is also possible to select and use a mixture of two or more. In addition, 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.

  The blending ratio of the components constituting the ink is not limited, and can be appropriately prepared within a dischargeable range from the selected inkjet recording method, the discharge force of the head, the nozzle diameter, and the like. Generally, on a mass basis, the colorant is 0.1 to 10%, the resin component is 0.1 to 20%, the solvent is 5 to 40%, the surfactant is 0.01 to 5% or less, and the rest is pure water. The adjusted ink can be used.

  When ink is ejected to the surface of the intermediate transfer member, the coating layer of the wettability improving component and the image fixing component formed in the steps (a) and (b) is usually fine as long as these are thin layers. In some cases, it may be preferable to perform a drying step prior to step (c) and sufficiently discharge the ink after discharging the above-described components. When forming an image, ink is ejected in consideration of the inversion of the image by transfer. That is, a mirror image obtained by mirror-reversing an image to be formed on a recording medium as a transfer destination is formed on the intermediate transfer member.

4). Step (d): Step of transferring the ink image formed on the intermediate transfer member to the recording medium 9 The recording medium 9 is brought into contact with the image forming surface of the intermediate transfer member 1 by the pressure roller 10 and the ink is transferred. Receive. According to the embodiment of the method of the present invention, at this stage, the ink has a sufficiently high viscosity on the intermediate transfer body 1, so recording such as printing paper having a small ink absorption amount or a film having no ink absorption amount is possible. A good image can be formed on the medium.

  However, if the time from the ink image formation in step (c) to the transfer in step (d) is extremely short, the amount of water in the ink may not be reduced to the amount of water allowed by the recording medium due to natural evaporation. There are cases. In consideration of such a case, as shown in FIG. 1, it is desirable to arrange a moisture removal promoting device 7 between ink image formation and transfer, and promote moisture removal in the ink by such a device. As means for promoting moisture removal, for example, the ink image forming surface is blown or heated, or the heating roller 8 is brought into contact with the back surface side of the intermediate transfer member 1 as shown in FIG. It is effective. When the time from step (c) to (d) becomes extremely long, it is desirable to adjust the volatility of the ink solvent used and the means for suppressing the volatilization of the solvent in the ink.

  Furthermore, the image recording apparatus according to the embodiment of the present invention can be provided with means for accelerating the fixing of the image formed on the recording medium. By applying pressure through a fixing accelerating device such as the fixing roller 11 shown in FIG. 1, the recorded image has excellent surface smoothness. Furthermore, by heating the fixing roller 11, the printed matter can be instantly made robust.

  In the apparatus illustrated in FIG. 1, the intermediate transfer member after the ink image is transferred is further cleaned by the cleaning unit 12 disposed next in order to receive the next image. As a means for cleaning, it is basically desirable to use means such as washing with water or wiping, direct washing such as applying a shower or bringing it into contact with the water surface, or wiping the surface by wetting a Morton roller. Of course, it is also effective to use these in combination.

  Furthermore, if necessary, it is also effective to dry the surface of the intermediate transfer member by a method such as applying a dry Molton roller after washing or blowing air. Depending on the ink used, it is also effective to perform cleaning with a wettability improving component. In that case, the coating device 3 for applying the wettability improving component described above also serves as a cleaning means.

  Although the respective steps have been described above, the technical point in the embodiment of the present invention is that the image fixing component can be uniformly applied to the surface of the intermediate transfer member, or at a desired position on the surface of the intermediate transfer member. In summary, the image fixing component can be held. Proposals have been made in the past to suppress the disturbance (beading, bleeding, etc.) of the ink image on the intermediate transfer member by applying a component (image fixing component) that can fix the ink image on the surface of the intermediate transfer member ( For example, see Patent Document 6). However, in these proposals, the image fixing component itself cannot be uniformly applied on the intermediate transfer member, or the image fixing component cannot be held at a desired position on the surface of the intermediate transfer member, so that the deterioration of the ink image is suppressed. I can't. In the prior art, in order to uniformly apply the image fixing component, a material having an excellent wettability has been used as the intermediate transfer member. However, a material with good wettability has a high surface energy, and the ink image is fixed through the image fixing component and cannot be transferred, or the transfer rate is very low even if it is not fixed. is there. If the transfer rate is low, more ink must be applied onto the intermediate transfer member in order to obtain the required image density on the recording medium. An increase in the ink application amount and a decrease in the transfer rate have the following adverse effects.

1) Increase in bleeding and beading Both bleeding and beading are caused by contact between ink droplets. As the amount of ink supplied onto the intermediate transfer member increases, the probability of ink droplet contact also increases.

2) Increase in water volatilization amount When the amount of ink per unit surface area on the intermediate transfer member increases, the time and energy amount required for water removal increase. This also leads to an increase in the size of the device.

3) Deterioration of dot gain during transfer The more ink on the intermediate transfer body, the more the dot diameter will be crushed by the pressure during transfer, causing a reduction in resolution.

4) Increase in load during cleaning The more ink remaining on the surface of the intermediate transfer body after transfer, the more difficult the cleaning becomes. This also leads to an increase in the size of the device.

5) Decrease in ink use efficiency The ratio of ink used for image formation decreases, the running cost increases, and waste increases.

  Such a low transfer rate is not preferable because various problems occur. Therefore, it is desirable to realize a high transfer rate. In order to improve the transfer rate, it is necessary to use an intermediate transfer member having a surface of a releasable material having a low surface energy or a non-absorbing material. However, the image fixing component is repelled on the surface of the intermediate transfer member simply by applying the image fixing component to the intermediate transfer member having a releasable or non-absorbing surface without any treatment. End up.

  In view of the above, a technique that can uniformly apply an image fixing component to an intermediate transfer member having a surface of a releasable material or a non-absorbing material, or an intermediate transfer having a surface of a releasable material or a non-absorbing material These problems can be solved if a technique capable of holding the image fixing component at a desired position on the body can be established.

  According to the image forming method in the embodiment of the present invention, prior to applying the image fixing component to the intermediate transfer body having the surface of the releasable material or the non-absorbable material capable of realizing a high transfer rate, Since the wettability improving component that improves the wettability of the transfer surface is applied to the surface of the intermediate transfer body, the image fixing component can be uniformly applied to the intermediate transfer body, and the image is fixed at a desired position on the intermediate transfer body. The components can be retained. As a result, a high-quality ink image can be formed on the intermediate transfer member, and the ink image can be transferred to a recording medium at a high transfer rate. Therefore, efficient and good image formation is possible regardless of the absorption characteristics of the recording medium as the transfer destination.

  Next, the present invention will be specifically described with reference to examples and comparative examples. In the text, “parts” and “%” are based on mass unless otherwise specified.

  Hereinafter, the image recording method of this embodiment will be described step by step.

(A) Application of wettability improving component 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.) with a thickness of 0.5 mm was used as an intermediate transfer member. . First, the surface of the intermediate transfer member was coated with a fluorosurfactant (Nethos FT-400S manufactured by Neos) using a roll coater.

(B) Application of Image Fixing Component Next, a 10% by mass aqueous solution of aluminum chloride hexahydrate was applied with a roll coater.

(C) Ink image formation In an ink jet recording apparatus (nozzle density 1200 dpi, ejection amount 4 pl, drive frequency 8 kHz), the above components (a) and (b) are applied onto the transfer body on which the components are applied to the surface. Then, a character image with mirror inversion was formed. 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.
・ Pigment (Mitsubishi Chemical Carbon Black MCF88) 5 parts ・ Styrene-acrylic acid-ethyl acrylate copolymer (acid value 240, weight average molecular weight 5000) 1 part ・ Glycerin 10 parts ・ Ethylene glycol 5 parts ・ Surfactant ( Kawaken Fine Chemicals Acetylenol EH) 1 part ・ Ion-exchanged water 78 parts

(D) Transfer The intermediate transfer body after the above-described series of steps and the surface-coated printing paper with low ink absorbability (Npi Co., Ltd., Npi coat, 40.5 kg) are brought into contact with a pressure roller to perform intermediate transfer. The recorded image on the body 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.

  Hereinafter, the image recording method of this embodiment will be described step by step.

(A) Application of wettability improving component In this example, 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 0.5 mm was used as an intermediate transfer member. . First, a fluorosurfactant (Surflon S-141 manufactured by Seimi Chemical Co., Ltd.) was applied to the surface of the intermediate transfer member with a roll coater.

(B) Application of image fixing component Next, the following aqueous solution was applied by a roll coater.
・ Calcium chloride dihydrate 10 parts Fluorosurfactant 1 part (Surflon S-141 manufactured by Seimi Chemical Co., Ltd.)
-1 part of cross-linking agent (Nisshinbo Carbodilite V-02)
・ 88 parts of ion exchange water

(C) Ink image formation On an intermediate transfer body in which each component is applied to the surface in (a) and (b) described above in an ink jet recording apparatus (nozzle density 1200 dpi, ejection amount 4 pl, drive frequency 8 kHz). Then, a character image that was mirror-reversed using four colors of ink was formed. 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 5 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 (acetyleneol EH manufactured by Kawaken Fine Chemicals) 1 part ・ Ion exchange 78 parts of water

(D) Transfer First, air is received on the surface of the recording image on the intermediate transfer member by a blower installed between the ink jet recording apparatus and the pressure roller. Thereafter, the intermediate transfer member was contacted with a surface-coated printing paper having a low ink absorbability (Npi coat, 40.5 kg of 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. Further, the rubability of the recorded image improved with time, and was completely fixed after 12 hours.

  Next, the residual ink slightly remaining on the intermediate transfer member was removed by contacting with a wet Molton roller.

  Hereinafter, the image recording method of this embodiment will be described step by step.

(A) Application of wettability improving component In this example, an aluminum drum coated with a silicone rubber having a rubber hardness of 80 ° (KE24 manufactured by Shin-Etsu Chemical Co., Ltd.) with a thickness of 0.5 mm was used as an intermediate transfer member. . First, a silicone surfactant (SILWET L77 manufactured by Nihon Unicar) was applied to the surface of the intermediate transfer member with a roll coater.

(B) Application of image fixing component Next, a 5% by mass aqueous solution of a polymer flocculant (C577S manufactured by Mitsui Cytec) was applied by a roll coater.

(C) Ink image formation On an intermediate transfer body in which each component is applied to the surface in (a) and (b) described above in an ink jet recording apparatus (nozzle density 1200 dpi, ejection amount 4 pl, drive frequency 8 kHz). Then, a character image that was mirror-reversed using four colors of ink was formed. 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.
Each of the following dyes 4 parts Black: CI. Food black 2
Cyan: CI. Direct Blue 199
Magenta: CI. Acid Red 289
Yellow: CI. Acid Yellow 23
・ Glycerin 10 parts ・ Diethylene glycol 5 parts ・ Surfactant (Acetylenol EH manufactured by Kawaken Fine Chemicals) 1 part ・ Ion-exchanged water 80 parts

(D) Transfer First, the surface of the recorded image on the intermediate transfer member is heated by an infrared heater installed between the ink jet recording apparatus and the pressure roller. Thereafter, the intermediate transfer member was contacted with a surface-coated printing paper having a low ink absorbability (Npi coat, 40.5 kg of 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.

  Subsequently, the residual ink slightly remaining on the intermediate transfer member was removed by bringing it into contact with a wet Molton roller.

  Hereinafter, the image recording method of this embodiment will be described step by step.

(A) Application of wettability improving component In this example, an aluminum drum coated with 0.7 mm thick fluororubber (Aphras 150c manufactured by Asahi Glass) having a rubber hardness of 30 ° was used as an intermediate transfer member. . First, a solid fluorosurfactant (Surflon SC101 manufactured by Seimi Chemical) was applied in contact with the surface of the intermediate transfer member.

(B) Application of image fixing component Next, an image fixing component according to the following prescription was applied only to the image forming portion with an ink jet recording apparatus (nozzle density 1200 dpi, ejection amount 4 pl, driving frequency 1 kHz).
・ Calcium chloride dihydrate 10 parts ・ Glycerin 10 parts ・ Diethylene glycol 5 parts ・ Surfactant (Acetyleneol EH manufactured by Kawaken Fine Chemicals) 1 part ・ Ion-exchanged water 74 parts

(C) Ink image formation On an intermediate transfer body in which each component is applied to the surface in (a) and (b) above with an ink jet recording apparatus (nozzle density 1200 dpi, ejection amount 4 pl, drive frequency 1 kHz). Then, a character image that was mirror-reversed using four colors of ink was formed. 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.
Each of the following dyes 4 parts Black: CI. Food black 2
Cyan: CI. Direct Blue 199
Magenta: CI. Acid Red 289
Yellow: CI. Acid Yellow 23
・ Styrene-acrylic acid-ethyl acrylate copolymer (acid value 330, weight average molecular weight 4000) 6 parts ・ Glycerin 5 parts ・ Diethylene glycol 5 parts ・ Surfactant (Acetyleneol EH manufactured by Kawaken Fine Chemicals) 1 part ・ Ion-exchanged water 79 parts

(D) Transfer First, the surface of the recorded image on the intermediate transfer member is heated by an infrared heater installed between the ink jet recording apparatus and the pressure roller. Thereafter, the intermediate transfer member was contacted with a surface-coated printing paper having a low ink absorbability (Npi coat, 40.5 kg of Nippon Paper Industries Co., Ltd.) with a pressure roller to transfer the recorded image. Subsequently, a heated mirror surface metal roller (surface temperature 60 ° C.) was contact-pressed on the image recording surface to fix the image. As a result, no beading was observed in the image on the printing paper, and good image quality was obtained. Also, the scratching immediately after output was good.

  Subsequently, the residual ink slightly remaining on the intermediate transfer member was removed by bringing it into contact with a wet Molton roller.

<Comparative Example 1>
In Example 3, image recording was performed in the same manner as in Example 3 except that no ink wettability improving component was added to the intermediate transfer member. As a result, the ink image on the intermediate transfer member was distorted, and further, a sufficient image on the printing paper after transfer was not obtained.

<Comparative example 2>
In Example 2, image recording was performed in the same manner as in Example 1 except that the surface of the intermediate transfer member was butyl rubber having no releasability. As a result, to reproduce the image obtained in Example 2, approximately 1.5 times as much ink is required as in Example 2, and it is necessary to remove moisture by blowing air from image formation to transfer. The time taken was 1.7 times. In addition, the dot gain was slightly larger than the image obtained in Example 2.

It is a conceptual diagram of an apparatus applicable with the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intermediate transfer body 2 Releasable surface layer 3 Coating apparatus A
4 Coating device B
DESCRIPTION OF SYMBOLS 5 Inkjet recording device 6 Ink dot 7 Moisture removal promotion apparatus 8 Heating roller 9 Recording medium 10 Pressure roller 11 Fixing roller 12 Cleaning unit

Claims (16)

Providing the intermediate transfer member with a first liquid for improving the wettability of the intermediate transfer member surface;
Applying a second liquid for reducing the fluidity of ink on the intermediate transfer body to the intermediate transfer body to which the first liquid is applied;
Forming an ink image on the intermediate transfer body by applying the ink from an inkjet recording head to the intermediate transfer body to which the first liquid and the second liquid are applied;
Transferring an ink image formed on the intermediate transfer member to a recording medium;
An image forming method comprising: Applying a first liquid for improving the wettability of the surface of the intermediate transfer member to the intermediate transfer member having a non-absorbing surface;
Applying a second liquid for aggregating the color material of the ink to the intermediate transfer body to which the first liquid is applied;
Forming an ink image on the intermediate transfer body by applying the ink from an inkjet recording head to the intermediate transfer body to which the first liquid and the second liquid are applied;
Transferring an ink image formed on the intermediate transfer member to a recording medium;
An image forming method comprising: Applying a first liquid containing a surfactant to an intermediate transfer member having a surface containing at least one material of fluorine rubber and silicone rubber;
Applying a second liquid for aggregating the color material of the ink to the intermediate transfer body to which the first liquid is applied;
Forming an ink image on the intermediate transfer body by applying the ink from an ink jet recording head to the intermediate transfer body to which the first liquid and the second liquid are applied;
Transferring an ink image formed on the intermediate transfer member to a recording medium;
An image forming method comprising: Surface of the intermediate transferring body, the image forming method according to claim 1 or 2, characterized in that it comprises a compound containing at least fluorine or silicone. The surface of the intermediate transfer member, the image forming method according to any one of claims 1 to 3, characterized in that for the range of rubber hardness 10 to 100 °. The image forming method according to claim 1, wherein the first liquid is a liquid containing a surfactant. The image forming method according to any one of claims 1 to 3, characterized in that the position for applying the first liquid, is changed according to an image to be formed. The second liquid, the image forming method according to any one of claims 1 to 3, characterized in that a liquid containing metal ions. The image forming method according to any one of claims 1 to 3, characterized in that the position for applying the second liquid is changed in accordance with the image to be formed. The image forming method according to claim 8, wherein the second liquid contains a surfactant. Said first liquid, said second liquid, of the ink, an image forming method according to any one of claims 1 to 3, characterized in that comprises at least one crosslinking agent. The image forming method according to any one of claims 1 to 11, characterized in that it comprises a step to facilitate removal of the solvent contained in the image of the ink formed on the intermediate transfer body. Wherein at least one of the first liquid and the second liquid, the image forming method according to any one of claims 1 to 12, characterized in that it is applied using a head of an ink jet method. An apparatus for forming an image of the ink on the recording medium by transferring an image of the ink formed on the intermediate transfer member to the recording medium,
First applying means for applying a first liquid for improving the wettability of the surface of the intermediate transfer member to the intermediate transfer member;
Second applying means for applying a second liquid for reducing the fluidity of the ink to the intermediate transfer body to which the first liquid is applied;
An ink jet recording head that applies the ink to the intermediate transfer body to which the first liquid and the second liquid are applied, based on image data;
A transfer unit for transferring an image of ink applied to the intermediate transfer member by the inkjet recording head from the intermediate transfer member to the recording medium;
An image forming apparatus comprising: A method for producing a recorded matter in which an image of ink is formed on a recording medium,
Against the intermediate transfer member the first liquid has been applied to improve the wettability of the surface of the intermediate transfer member,
Applying a second liquid for aggregating the colorant of the ink;
Forming an ink image on the intermediate transfer body by applying the ink from an inkjet recording head to the intermediate transfer body to which the first liquid and the second liquid are applied;
Producing the recorded matter by transferring an image of the ink formed on the intermediate transfer member to the recording medium;
A method for producing a recorded matter comprising: The method for producing a recorded matter according to claim 15, wherein the surface of the intermediate transfer member is made of a releasable material .

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