JP4878585B2 - Inkjet recording apparatus and recording method - Google Patents

Description

  The present invention relates to an ink jet recording apparatus and a recording method, and more particularly, an image is formed on an intermediate transfer member by ejecting ink droplets from an ink jet recording head, and the image formed on the intermediate transfer member is recorded on a recording medium. The present invention relates to a transfer type ink jet recording apparatus and a recording method for transferring to a recording medium.

  In general, an ink jet recording apparatus has a low running cost, a low noise during a recording operation, can be recorded on a wide variety of recording media, and is widely used from home use to industrial use. For example, a method (direct recording method) is known in which ink droplets are ejected from a nozzle of an ink jet recording head (ink jet head) to a recording medium.

  However, in the direct recording method, liquid (ink) is directly ejected from the ink jet head onto the recording medium. Therefore, when a permeable recording medium (for example, plain paper or recycled paper) is used, curling or cockling is performed. If a non-permeable recording medium (for example, plastic or metal) is used, ink bleeding or color mixing may occur on the recording medium. There is a problem that quality cannot be obtained.

  In order to solve such problems, a transfer method in which an image is formed on an intermediate transfer member by discharging ink from the inkjet head to the intermediate transfer member, and the image formed on the intermediate transfer member is transferred to a recording medium. Has been proposed. According to the transfer method, after an image is formed on the intermediate transfer member, it is possible to transfer to the recording medium after removing the solvent component (liquid) on the intermediate transfer member, depending on the type of the recording medium. High quality images can be obtained without any problems.

  For example, in Patent Document 1, an image is formed by ejecting ink onto an intermediate transfer medium in which a transfer layer (release layer) is provided on a substrate, and the image is transferred to a recording medium (paper) together with the transfer layer. An inkjet recording apparatus and a recording method for transferring are described.

In Patent Document 2, ink and a liquid containing an adhesive compound (adhesive ink) are separately ejected onto a substrate, the surface is heated, and then transferred to a recording medium (paper). An ink jet recording method is described.
Japanese Patent Laid-Open No. 2002-240411 Japanese Patent Laid-Open No. 2003-1924

  However, in the invention described in Patent Document 1, when the transfer layer is provided on the entire surface, the transfer layer is also transferred to a region where there is no image on the paper, and thus the texture of the paper (glossiness, hand feeling). Will change.

  Further, in the invention described in Patent Document 2, when the adhesive ink dots are not ejected, or when the ejection positions of the ink dots and the adhesive ink dots are greatly displaced, Heat is applied after only the ink is directly applied, resulting in poor transferability to paper, and the ink may not be removed from the substrate during subsequent cleaning.

  The present invention has been made in view of such circumstances, and an ink jet recording apparatus and a recording method capable of improving transferability and realizing a high quality image while maintaining the texture of a non-image portion in a recording medium. The purpose is to provide.

  In order to achieve the object, the invention described in claim 1 includes a first release agent applying means for applying a first release agent that softens at a predetermined temperature on the entire surface of the intermediate transfer member, and the first release agent. A second release agent that softens at a lower temperature than the first release agent at the same position as the dot formation position determined according to the image data on the intermediate transfer body to which the release agent has been applied. A second release agent droplet ejecting means for ejecting ink, an ink droplet ejecting means for ejecting an ink droplet to a dot formation position on the intermediate transfer body on which the second release agent is ejected, and A transfer unit that transfers an image formed on the intermediate transfer member to a recording medium; a cleaning unit that cleans the intermediate transfer member; a heating unit that heats the intermediate transfer member; and the first mold release. The glass transition temperature of the agent is Tg1, the glass transition temperature of the second release agent is Tg2, When the Tt the temperature, the temperature at the time of cleaning Tc of time, characterized by comprising control means for controlling said heating means so as to satisfy the following equation Tc> Tg1> Tt> Tg2, the.

  According to the present invention, after the first release layer made of the first release agent is formed on the entire surface of the intermediate transfer member, the second release agent and the ink with respect to the dot formation position determined according to the image data. Control is performed so that droplets are sequentially ejected, and only the second release agent is in a fluid state at the time of transfer, and the first release agent is also in a fluid state at the time of cleaning. For this reason, the first release agent is not transferred to the recording medium, the texture of the non-image area on the recording medium can be maintained, and the transferability can be improved. Further, the post-transfer residue on the intermediate transfer body can be easily removed, and defective cleaning can be prevented. As a result, a high-quality image can be realized.

  According to the second aspect of the present invention, there is provided a first release agent applying means for applying a first release agent as an electrorheological fluid to the entire surface of the intermediate transfer member, and the first release agent. A second release agent droplet ejecting means for ejecting a second release agent that softens at a predetermined temperature to the same position as a dot formation position determined according to image data on the intermediate transfer member; (2) An ink droplet ejecting means for ejecting ink droplets onto the dot formation position on the intermediate transfer member on which the release agent has been ejected, and an image formed on the intermediate transfer member on the recording medium Transfer means for transferring, cleaning means for cleaning the intermediate transfer member, heating means for heating the intermediate transfer member, electric field applying means for applying an electric field to the intermediate transfer member, and second release agent Glass transition temperature Tg, transfer temperature Tt, cleaning temperature c, the first control means for controlling the heating means so as to satisfy the following formula Tt> Tg and Tc> Tg; and after the application of the first release agent, the second release agent The electric field applying unit is controlled so that the electric field is continuously applied to the intermediate transfer body from before the droplet is dropped until the transfer is completed, and the application of the electric field is canceled after the transfer is completed until the cleaning is started. And a second control means.

  Furthermore, the invention described in claim 3 is provided with a first release agent applying means for applying a first release agent that softens at a predetermined temperature on the entire surface of the intermediate transfer member, and the first release agent. A second release agent droplet ejecting means for ejecting a second release agent that is an electrorheological fluid to the same position as a dot formation position determined according to image data on the intermediate transfer member; (2) An ink droplet ejecting means for ejecting ink droplets onto the dot formation position on the intermediate transfer member on which the release agent has been ejected, and an image formed on the intermediate transfer member on the recording medium Transfer means for transferring, cleaning means for cleaning the intermediate transfer member, heating means for heating the intermediate transfer member, electric field applying means for applying an electric field to the intermediate transfer member, and the first release agent Glass transition temperature Tg, transfer temperature Tt, cleaning temperature c, the first control means for controlling the heating means so as to satisfy the following formula: Tc> Tg> Tt; and after the ink droplet is ejected after the second release agent is ejected. A second control means for controlling the electric field applying means so as to continue applying an electric field to the intermediate transfer member until transfer is started and to cancel application of the electric field when transfer is started. It is characterized by that.

  According to the invention described in claim 2 or 3, as in the invention described in claim 1, the first release agent is not transferred to the recording medium, and the texture of the non-image area in the recording medium is increased. While being able to maintain, transferability can be improved. Further, the post-transfer residue on the intermediate transfer member can be easily removed, and transfer defects can be prevented. As a result, a high-quality image can be realized.

  The invention according to claim 4 relates to an embodiment of the invention according to any one of claims 1 to 3, wherein the second release agent droplet ejecting means is only at the same position as the dot forming position. In addition, the second release agent is ejected at a position adjacent to the dot formation position.

  According to the fourth aspect of the present invention, the landing stability of ink droplets is improved, and the image quality is further improved.

  A fifth aspect of the invention relates to an embodiment of the invention according to any one of the first to fourth aspects, wherein the second release agent droplet ejection unit and the ink droplet ejection unit have the same resolution. It is characterized by comprising an inkjet head.

  According to the fifth aspect of the invention, the second release agent and the ink droplet can be accurately ejected corresponding to the dot formation position determined according to the image data, and the transferability is improved. .

  The invention described in claim 6 relates to an embodiment of the invention described in any one of claims 1 to 5, wherein the contact angle of the second release agent with respect to the intermediate transfer member is θ1, the first When the contact angle of the second release agent with respect to the release layer formed by the release agent is θ2, the following relationship θ1> θ2 is satisfied.

  According to the invention described in claim 6, even when the surface energy of the intermediate transfer member is low, it is possible to stably apply the second release agent on the release layer formed by the first release agent. Therefore, the range of material selection for the intermediate transfer member is widened.

  The invention according to claim 7 relates to an embodiment of the invention according to any one of claims 1 to 6, wherein the second release agent is a component that aggregates the color material of the ink droplets, Alternatively, it contains a component that thickens the ink droplet after landing of the ink droplet.

  According to the seventh aspect of the present invention, the ink droplets ejected to the dot formation position determined according to the image data react with the second release agent on the intermediate transfer member, and the color material is changed. Aggregate. Therefore, landing interference between ink droplets that are ejected to adjacent dot formation positions is prevented.

The invention according to claim 8 relates to an embodiment of the invention according to any one of claims 1 to 7, and the storage elastic modulus at the transfer temperature of the first release agent and the second release agent. The difference is 10 ² [Pa] or more.

  Moreover, in order to achieve the said objective, invention of Claim 9-11 provides a method invention.

  That is, the invention described in claim 9 includes a step of applying a first release agent that softens at a predetermined temperature to the entire surface of the intermediate transfer member, and a step on the intermediate transfer member to which the first release agent is applied. A step of ejecting a second release agent that softens at a lower temperature than the first release agent at the same position as the dot formation position determined according to the image data; and the second release A step of ejecting ink droplets onto a dot formation position on the intermediate transfer body on which an agent has been deposited, a step of transferring an image formed on the intermediate transfer body to a recording medium, and The step of cleaning the intermediate transfer member, the glass transition temperature of the first release agent Tg1, the glass transition temperature of the second release agent Tg2, the transfer temperature Tt, and the cleaning temperature Tc When doing so, control is performed to satisfy the following formula: Tc> Tg1> Tt> Tg2 It is characterized by having a process.

  The invention according to claim 10 includes a step of applying a first release agent that is an electrorheological fluid to the entire surface of the intermediate transfer member, and a step on the intermediate transfer member to which the first release agent is applied. A step of ejecting a second release agent that softens at a predetermined temperature to the same position as a dot formation position determined according to image data, and the intermediate transfer body on which the second release agent is ejected A step of ejecting ink droplets on the upper dot formation position, a step of transferring an image formed on the intermediate transfer member to a recording medium, and a step of cleaning the intermediate transfer member; A step of controlling the second release agent to have a glass transition temperature Tg, a transfer temperature Tt, and a cleaning temperature Tc, so that the following formulas Tt> Tg and Tc> Tg are satisfied: After applying the first release agent and before the second release agent is ejected A step of continuously applying an electric field to the intermediate transfer member until the transfer is completed, and controlling to release the application of the electric field until the cleaning is started after the transfer is completed. .

  The invention according to claim 11 includes a step of applying a first release agent that softens at a predetermined temperature on the entire surface of the intermediate transfer member, and the intermediate transfer member provided with the first release agent. A step of ejecting the second release agent, which is an electrorheological fluid, to the same position as the dot formation position determined according to the image data, and the intermediate transfer body on which the second release agent has been ejected A step of ejecting ink droplets on the upper dot formation position, a step of transferring an image formed on the intermediate transfer member to a recording medium, and a step of cleaning the intermediate transfer member; When the glass transition temperature of the first release agent is Tg, the temperature at the time of transfer is Tt, and the temperature at the time of cleaning is Tc, the step of controlling to satisfy the following formula: Tc> Tg> Tt; The transfer starts after the ink is ejected and before the ink droplet is ejected. And a process of continuing to apply an electric field to the intermediate transfer member immediately before the transfer, and controlling the application of the electric field to be canceled at the latest after the completion of the transfer at the time of cleaning.

  According to the present invention, the first release agent is not transferred to the recording medium, the texture of the non-image area on the recording medium can be maintained, and the transferability can be improved. Further, the post-transfer residue on the intermediate transfer body can be easily removed, and defective cleaning can be prevented. As a result, a high-quality image can be realized.

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

  First, an ink jet recording method according to the present invention will be described, and then a configuration example (first to third embodiments) of an ink jet recording apparatus according to the present invention to which the ink jet recording method is applied will be described.

[Inkjet recording method]
1 and 2 are explanatory views showing an outline of the ink jet recording method according to the present invention.

  In the ink jet recording method according to the present invention, as shown in FIG. 1, first, a first release agent α is applied onto the entire surface of the intermediate transfer body 10 to apply a first release layer to the entire surface of the intermediate transfer body 10. 12 is formed (FIG. 1A). Next, the second release agent β from each nozzle of the inkjet head (not shown) corresponding to the dot formation position (position where the ink droplet is ejected) determined according to the image data (recorded image). To form a second release layer 14 on the first release layer 12 (FIG. 1B). Further, ink dots 16 are formed on the second release layer 14 by ejecting ink droplets from the respective nozzles of an inkjet head (not shown) to the dot formation positions determined according to the image data. (FIG. 1 (c)).

  Thus, after forming an ink image composed of ink dots 16 via the first release layer 12 and the second release layer 14 on the intermediate transfer member 10, the ink image formed on the intermediate transfer member 10 is recorded. Transfer is performed on the medium 18 (FIG. 1D). Further, after that, the transfer residue on the intermediate transfer body 10 is attached to the cleaner 20 (corresponding to a cleaning roller 38A (see FIG. 4) described later) and removed (FIG. 1 (e)). Thereafter, the above steps are sequentially repeated.

  Table 1 shows an example of the first release agent α, the second release agent β, and the ink used in the present invention.

  For the “first release agent α” and the “second release agent β”, for example, the resin itself may be applied to the intermediate transfer body 10 by the same method as the development in electrophotography, or the resin may be added. A liquid dissolved or dispersed in a solvent may be applied. That is, the “first release agent α” and the “second release agent β” in the present invention are not limited to those in the solid state, but are used in a broad concept including those in the liquid state.

  In addition, regarding the first release layer 12 and the second release layer 14, when the release agents α and β are in a liquid state, a residue (for example, resin is removed from the solvent after the solvent is evaporated). In the case of being dissolved or dispersed in the resin, the resin) is mainly shown. However, when the amount of the solvent is small when each release agent α, β is applied, it may be handled as a release layer without necessarily passing through the evaporation step. . In the case of an electrorheological fluid described later, since the viscoelasticity of the fluid itself is changed by an electric field, the fluid itself (that is, a mixture of a solvent and a dispersion) is defined as a “release layer”.

  In the present invention, when the glass transition temperature of the first release agent α is Tg1, the glass transition temperature of the second release agent β is Tg2, the transfer temperature is Tt, and the cleaning temperature is Tc, the following formula Tc> Tg1> The transfer temperature (Tt) and the cleaning temperature (Tc) are controlled so as to satisfy the relationship of Tt> Tg2. For this reason, at the time of transfer, only the second release agent β is in a fluid state without the first release agent α being in a fluid state, and as shown in FIG. A part (or all) of the second release layer 14 is separated (hereinafter, this phenomenon is also referred to as “crying off”), and a part (or all) of the separated second release layer 14 is separated. Is transferred to the recording medium 18. Thereby, the first release layer 12 made of the first release agent α is not transferred to the recording medium 18, the texture of the non-image area on the recording medium 18 can be maintained, and the transferability is also improved. . For example, an image can be transferred while maintaining the texture of paper.

  In the present invention, “transfer temperature” and “cleaning temperature” refer to the temperature of the release layer itself in each process (transfer process and cleaning process). In practice, when a substance comes into contact with the release layer, the temperature of the release layer is substantially equal to the temperature of the substance in contact, so the transfer temperature is the temperature of the recording medium 18 at the time of transfer and the cleaning temperature. May be regarded as the temperature of the cleaner 20 (cleaning roller 38A) during cleaning.

  At the time of cleaning, not only the second release agent β but also the first release agent α is in a fluid state, and as shown in FIG. 1E, the second release layer made of the second release agent β. 14 and the first release layer 12 made of the first release agent α adheres to the cleaner 20, so that the post-transfer residue (each release agent α, β, ink, dust, etc.) on the intermediate transfer member can be easily obtained. Therefore, it is possible to prevent defective cleaning. As a result, a high-quality image can be realized.

  A part of the first release layer 12 made of the first release agent α may remain on the intermediate transfer member 10 (FIG. 1 (e)), but the first release layer 12 is formed on the intermediate transfer member 10. Since the mold agent α is applied again, the transferability in the next step is not affected.

  According to the present invention, for example, as shown in FIG. 2, after the first release layer 12 is formed on the entire surface of the intermediate transfer member 10 (FIG. 2A), dot formation determined according to image data is performed. Even when the second release agent β is ejected corresponding to the position, there is an undischarge nozzle in the inkjet head, and even when the second release agent β is not ejected to some dot formation positions. (FIG. 2B), the ink droplets that are subsequently ejected land on the first release layer 12 instead of the intermediate transfer member 10 (FIG. 2C), so that the surface of the intermediate transfer member 10 Is not stained with the color material contained in the ink, and transfer defects can be prevented. Even when the ink dots 16A formed by the ink droplets landed on the first release layer 12 are not transferred to the recording medium 18 (FIG. 2D), the ink dots 16A are applied to the cleaner 20 during cleaning. Can be removed by attaching (FIG. 2E).

  Further, after the first release layer 12 made of the first release agent α is formed on the entire surface of the intermediate transfer member 10, the second release agent β is ejected onto the first release layer 12. Therefore, even when the surface energy of the intermediate transfer member 10 is low, the second release agent β can be landed stably. That is, when the contact angle of the second release agent β with respect to the intermediate transfer member 10 is θ1, and the contact angle of the second release agent β with respect to the first release agent α is θ2, the following relationship θ1> θ2 is satisfied. As a result, it is possible to stably apply the second release agent β as compared with the case where it is directly applied onto the intermediate transfer member 10. As a result, the material selection range of the intermediate transfer body 10 is widened, and it is possible to apply, for example, an intermediate transfer body 10 having a low surface free energy of 25 [mN / m] or less. As a result, a low surface free energy member such as silicon rubber can be used as the intermediate transfer member 10, and good transfer characteristics can be obtained.

  In addition, according to the present invention, even when the surface of the intermediate transfer member 10 is scratched, the first release layer 12 made of the first release agent α is formed on the entire surface of the intermediate transfer member 10. Therefore, it is possible to cover the scratched portion, so that it is possible to prevent transfer defects due to scratches or the like.

  In the present invention, the second release agent β is ejected onto the contour portion located on the outer periphery of the image portion (dot ejection portion) formed by the ink droplets ejected onto the intermediate transfer body 10. Is preferred. Specifically, the second release agent β is ejected not only at the same position as the dot formation position determined according to the image data but also at a position adjacent to at least the dot formation position.

  For example, as shown in FIG. 3A, when an image portion 24 composed of 12 ink droplets (ink dots) 22 is formed, only the image portion 24 is formed as shown in FIG. Instead, the second release agent β may be ejected onto the contour portion 26 located on the outer periphery.

  In the example shown in the drawing, the second release agent β is ejected at positions adjacent to the vertical and horizontal directions with respect to the dot formation position where each ink droplet 22 is ejected. ), The second release agent β may be ejected at positions adjacent to the eight directions including the oblique direction. Also, as shown in FIG. 3D, a plurality of second release agents β are present in each of the four directions (vertical direction and horizontal direction) of the dot formation position where each ink droplet 22 is ejected. It may be ejected.

  In this way, the landing stability of the ink droplets is improved by ejecting the second release agent β onto the contour portion located on the outer periphery of the image portion. In particular, an image with excellent edge quality can be obtained.

  Moreover, instead of the mode in which the second release agent β is ejected onto the contour portion of the image portion described above, the ink droplet is applied to the same position as the dot formation position (position where the ink droplet is ejected). Compared to the above, it is possible to increase the droplet amount (droplet volume) of the second release agent β, and the same effect can be obtained.

  In the present invention, as will be described later, one of the first release agent α and the second release agent β is a material (for example, resin) that softens at a predetermined temperature, and the other There is a mode in which the release agent is an electrorheological fluid (ER fluid) whose viscosity changes according to the applied electric field.

In the present invention, the difference in storage elastic modulus at the transfer temperature between the first release agent α and the second release agent β measured by the rotary dynamic viscoelasticity measuring device is 10 ² [Pa] or more apart. The storage elastic modulus value (G _β ′) of the second release agent β is more preferably less than 2 × 10 ² [Pa].

[Inkjet recording device]
Next, configuration examples (first to third embodiments) of the ink jet recording apparatus according to the present invention will be described.

(First embodiment)
FIG. 4 is a configuration diagram showing an outline of the ink jet recording apparatus according to the first embodiment. As shown in FIG. 4, the ink jet recording apparatus 100 of the present embodiment is upstream with respect to the transport direction of the intermediate transfer body 10 (the direction indicated by arrow A in FIG. 4; hereinafter referred to as “intermediate transfer body transport direction”). In order, the first release agent application unit 30 for applying the first release agent α, the second release agent injection unit 32 for applying the second release agent β, and ink droplets are applied. The ink droplet forming unit 34 mainly includes a transfer unit 36 that transfers an ink image formed on the intermediate transfer body 10 to the recording medium 18, and a cleaning unit 38 that cleans the intermediate transfer body 10. The

  In the ink jet recording apparatus 100 of the present embodiment, the first release agent α that softens at a predetermined temperature and the second release agent β that has a lower glass transition temperature than the first release agent α are used. When the glass transition temperature of the first release agent α is Tg1, the glass transition temperature of the second release agent β is Tg2, the transfer temperature is Tt, and the cleaning temperature is Tc, the following formula Tc> Tg1> Tt> Tg2 is satisfied. In addition, the transfer temperature (Tt) and the cleaning temperature (Tc) are controlled. This control is performed mainly by a system controller (not shown in FIG. 4 and indicated by reference numeral 72 in FIG. 9) described later.

  An endless belt is applied to the intermediate transfer member 10 shown in FIG. 4, and the intermediate transfer member (endless belt) 10 includes a plurality of rollers (two stretching rollers 40A and 40B and heating for transfer heating in FIG. 4). The structure is wound around a counter roller 36B), and the power of a motor (not shown in FIG. 4 and indicated by reference numeral 88 in FIG. 9) is transmitted to at least one of these rollers, whereby intermediate transfer The body 10 is driven in the counterclockwise direction in FIG. 4 (the direction indicated by the arrow A in FIG. 1; the intermediate transfer body conveyance direction).

  The intermediate transfer member (endless belt) 10 is an image on which at least an ink image (primary image) is formed on the surface (image forming surface) 10 </ b> A facing the second release agent droplet ejecting portion 32 and the ink droplet ejecting portion 34. The formation region (not shown) has non-permeability that prevents ink droplets such as resin, metal, and rubber from penetrating. Further, at least the image forming area of the intermediate transfer member 10 is configured to form a horizontal surface (flat surface) having a predetermined flatness.

  Preferred materials used for the surface layer including the image forming surface 10A of the intermediate transfer body 10 include, for example, a polyimide resin, a silicon resin, a polyurethane resin, a polyester resin, a polystyrene resin, a polyolefin resin, and a polybutadiene resin. And publicly known materials such as polyamide resins, polyvinyl chloride resins, polyethylene resins, and fluorine resins.

  The first release agent application unit 30 disposed on the most upstream side in the intermediate transfer body conveyance direction includes an application roller 30A and a coating liquid container (not shown) in which the first release agent α is stored. The The application roller 30A is driven to rotate with respect to the intermediate transfer member 10, or can be independently driven and rotated by the application roller 30A, and is accommodated in the application liquid container according to the rotation of the application roller 30A. The first release agent α is applied on the entire image forming surface 10 </ b> A of the intermediate transfer body 10.

  The application roller 30A is preferably a porous material or a material with irregularities on the surface, and for example, a gravure roll can be used. In this example, the application member having the roller shape is exemplified as the means for applying the first release agent α to the intermediate transfer body 10. However, the means for applying the first release agent α to the intermediate transfer body 10 is a roller shape. However, the present invention is not limited to this, and a method of applying with a blade, a spray, or an inkjet head can be used.

  In the present invention, since the first release agent α needs to be applied to the entire image forming surface 10A of the intermediate transfer body 10, an embodiment in which it is applied by coating as in this example is preferable. Alternatively, the first release agent α may be applied directly, or a liquid in which the first release agent α is dispersed or dissolved in a solvent is applied onto the intermediate transfer member 10 and then the first release agent α. The first release layer 12 (see FIG. 1) may be formed on the intermediate transfer body 10 by evaporating the solvent by drying the liquid containing the liquid.

  The second release agent droplet ejection unit 32 disposed downstream of the first release agent application unit 30 in the intermediate transfer body conveyance direction includes an inkjet head (hereinafter simply referred to as “head”) 32A. The second release agent β is ejected from the head 32A onto the image forming surface 10A of the intermediate transfer body 10. The second release agent β is ejected corresponding to the dot formation position (position where the ink droplet is ejected) determined according to the image data (recorded image).

  In the present invention, as described above, the second mold release agent β is also ejected onto the contour portion located on the outer periphery of the image portion, that is, only at the same position as the dot formation position determined according to the image data. In addition, a mode in which the second release agent β is ejected also at a position adjacent to the dot formation position is preferable (see FIGS. 3A and 3B).

  In addition, a mode in which the second release agent β contains a component that aggregates the coloring material in the ink or a component (treatment agent) that thickens the ink droplet after landing of the ink droplet is also preferable. Since the second release agent β and the ink droplets react with each other on the intermediate transfer body 10 to form a color material aggregate, the landing interference between the ink droplets ejected at adjacent dot formation positions is prevented. be able to.

  Here, the ink includes dye ink in which the coloring material is dissolved in a molecular state (may be in an ionic state) in a liquid solvent, and the coloring material is dispersed in a minute mass in the liquid solvent. Pigment inks and the like. In other words, the color material contained in the ink is a substance that dissolves in a liquid solvent in a molecular state (may be in an ionic state), or a substance that disperses in a liquid solvent in a minute mass. Is mentioned.

  On the other hand, the treatment agent includes “a component that reacts with the ink to precipitate or insolubilize the color material in the ink”, “a component that generates a semi-solid substance (gel) containing the color material in the ink”, and the like. . The state of the treatment agent when reacting with the ink is preferably a solid or semi-solid state.

  As a means for causing such a reaction, a method in which an anionic coloring material in the ink is reacted with a cationic compound in the treatment agent, an ink having a pH different from each other and a treatment agent are mixed to adjust the pH of the ink. There are a method of causing dispersion and destruction of the pigment in the ink and aggregating the pigment, and a method of causing dispersion and destruction of the pigment in the ink by reaction with the polyvalent metal salt in the treating agent and aggregating the pigment.

  The ink droplet ejecting section 34 disposed on the downstream side of the second release agent droplet ejecting section 32 with respect to the intermediate transfer body transport direction is cyan (C) and magenta (M) from the upstream along the intermediate transfer body transport direction. , Yellow (Y) and black (K) ink jet heads (hereinafter simply referred to as “heads”) 34C, 34M, 34Y, and 34K are provided in this order. Corresponding ink droplets of the respective colors are ejected from the heads 34C, 34M, 34Y, 34K to the image forming surface 10A of the intermediate transfer member 10.

  As shown in FIG. 5, the head 32 </ b> A of the second release agent droplet ejection unit 32 and the heads 34 </ b> C, 34 </ b> M, 34 </ b> Y, 34 </ b> K of the ink droplet ejection unit 34 are each the maximum width of the image forming area in the intermediate transfer body 10. A full line type in which a plurality of nozzles for ink ejection (not shown in FIG. 5 and indicated by reference numeral 51 in FIG. 6) are arranged on the ink ejection surface over the entire width of the image forming area. The head is configured to be fixedly installed so as to extend in a direction orthogonal to the intermediate transfer member conveyance direction.

  In this example, the same structure as the heads 34C, 34M, 34Y, and 34K of the ink droplet ejection unit 34 is applied to the head 32A of the second release agent droplet ejection unit 32. Note that the head 32A of the second release agent droplet ejecting section 32 only needs to be capable of ejecting the second release agent β to the dot formation position determined according to the image data. A head having a structure in which the droplet ejection density (resolution) is lower than the heads 34C, 34M, 34Y, and 34K of the droplet ejection unit 34 may be applied.

  According to the configuration in which the full line type head having the nozzle row covering the entire width of the intermediate transfer body 10 is provided for each discharge liquid, the intermediate transfer body 10 and the second separation head are separated in the intermediate transfer body transport direction (sub-scanning direction). An ink image (primary image) is formed on the image forming area of the intermediate transfer member 10 by performing only one operation (ie, one sub-scan) of relatively moving the mold droplet ejecting section 32 and the ink droplet ejecting section 34. ) Can be recorded. As a result, high-speed printing is possible compared with the case where a serial (shuttle) type head that reciprocates in the direction (main scanning direction; see FIG. 5) perpendicular to the conveyance direction of the intermediate transfer member is applied, and print productivity is improved. Can be improved.

  In this example, the configuration of CMYK standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special color ink are used as necessary. May be added. For example, it is possible to add an ink head that discharges light-colored ink such as light cyan and light magenta, and the arrangement order of the color heads is not particularly limited.

  The liquid storage / loading unit (not shown) stores a liquid tank (not shown in FIG. 4) that stores the liquid (second release agent β or each color ink) supplied to each of the heads 32A, 34C, 34M, 34Y, and 34K. , Each tank communicates with a corresponding head via a required flow path, and supplies a corresponding liquid to each head. The liquid storage / loading unit includes notifying means (display means, warning sound generating means) for notifying that when the remaining amount of liquid in the tank is low, and a mechanism for preventing erroneous loading between liquids. Have.

  A heating and drying unit 42 is provided on the downstream side of the ink droplet ejection unit 34 and the upstream side of the transfer unit 36 in the intermediate transfer member conveyance direction. The heating and drying unit 42 includes a heater (not shown in FIG. 4, and indicated by reference numeral 89 in FIG. 9) provided on the back surface 10 </ b> B side of the image forming surface 10 </ b> A of the intermediate transfer member 10. The intermediate transfer member 10 on which the image is formed is heated from the back surface 10B side by a heater.

  The heating temperature range of the heater disposed in the heating and drying unit 42 is set lower than the heating temperature (transfer temperature) at the time of transfer. By preheating the image forming area of the intermediate transfer member 10, the heating temperature of the transfer unit 36 can be set lower than when no preheating is performed, and the transfer time of the transfer unit 36 is further reduced. be able to.

  The heating and drying unit 42 also serves as a solvent removing unit that dries the solvent contained in the ink image formed on the intermediate transfer member 10. As a configuration of the heating and drying unit 42, a heater is provided on the back surface 10B side of the intermediate transfer member 10, and hot air dried from the surface (image forming surface) 10A side of the intermediate transfer member 10 is applied to the intermediate transfer member 10. Is most convenient and preferred. Of course, instead of the heating drying unit 42 or in addition to the heating drying unit 42, for example, a roller-like solvent absorbing member (solvent removal roller) whose surface is made of a porous material is used to form an image on the intermediate transfer body 10. There is also an aspect in which the solvent is absorbed and removed by contacting the surface 10A. Further, instead of the solvent removal roller, a method of removing excess solvent from the intermediate transfer body 10 with an air knife can be applied.

  As a configuration of a paper feeding unit (not shown) for supplying the recording medium 18 to the transfer unit 36, a mode in which a magazine for rolled paper (continuous paper) is provided, or in place of or in combination with a magazine for rolled paper. There is a mode in which paper is supplied by a cassette in which cut papers are stacked and loaded. In the case of an apparatus configuration using roll paper, a cutter for cutting is provided, and the roll paper is cut into a desired size by the cutter. A plurality of magazines and cassettes having different paper widths and paper qualities may be provided.

  When a plurality of types of recording media can be used, an information recording body such as a barcode or a wireless tag that records the media type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Thus, it is preferable to automatically determine the type of recording medium (media type) to be used and perform ink ejection control so as to realize appropriate ink ejection according to the media type.

  Specific examples of the recording medium 18 applied to this example include permeable media such as plain paper and inkjet paper, non-permeable or low permeable media such as coated paper, and adhesive and release labels on the back. There are various media such as sticker paper, resin films such as OHP sheets, metal sheets, cloth, and wood.

  The transfer unit 36 disposed downstream of the heating and drying unit 42 in the conveyance direction of the intermediate transfer member includes a transfer heating roller having heaters (not shown in FIG. 4 and representative of a plurality of heaters shown in FIG. 9 by reference numeral 89). 36A and a heating counter roller 36B for heating and pressurizing nip disposed opposite to this, the intermediate transfer body 10 and the recording medium 18 are sandwiched between these rollers 36A and 36B, and a predetermined temperature is set. The ink image (primary image) formed on the intermediate transfer body 10 is transferred to the recording medium 18 by applying pressure at a predetermined pressure (nip pressure) while heating.

  The heating temperature (transfer temperature) at the time of transfer by the transfer unit 36 is determined according to the glass transition temperatures of the first release agent α and the second release agent β. Specifically, the transfer temperature (Tt) is lower than the glass transition temperature (Tg1) of the first release agent α and higher than the glass transition temperature (Tg2) of the second release agent β (that is, Tg1> Tt> Tg2), a heater disposed in the transfer section 36 is controlled by a system controller (not shown in FIG. 4, not shown in FIG. 9 and indicated by reference numeral 72).

  As a means for adjusting the nip pressure at the time of transfer in the transfer section 36, for example, a mechanism (drive means) for moving the transfer heating roller 36A in the vertical direction (shown by reference C) in FIG.

  A fixing unit (not shown) is preferably arranged downstream of the transfer unit 36 in the recording medium conveyance direction (the direction indicated by arrow B in FIG. 4). For example, the fixing unit includes a heating roller pair whose temperature can be adjusted in a range of 100 ° C. to 180 ° C., and the recording medium 18 on which the ink image is transferred by the transfer unit 36 passes between the heating roller pair. By doing so, the fixing property and scratch resistance of the ink image to the recording medium 18 can be improved.

  A cleaning unit 38 disposed on the downstream side of the transfer unit 36 with respect to the conveyance direction of the intermediate transfer member serves as a means for cleaning the surface of the intermediate transfer member 10 and removes the post-transfer residue while contacting the image forming surface 10A of the intermediate transfer member 10. The cleaning roller 38A is attached to the surface and removed.

  The structure of the cleaning means for removing the post-transfer residue from the intermediate transfer member 10 is not limited to the above example, but a method of wiping and removing the post-transfer residue using a blade, a brush roll, a water absorption roll, etc. System, air blow system for spraying clean air, adhesive roll system, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  In the inkjet recording apparatus 100 of the present embodiment, a heating unit 44 is provided at a position facing the cleaning roller 38A of the cleaning unit 38 with the intermediate transfer member 10 interposed therebetween. The heating unit 44 has the same configuration as that of the heating and drying unit 42 described above, and is provided with a heater (not shown in FIG. 4 and denoted by reference numeral 89 in FIG. 9) provided on the back surface 10B side of the image forming surface 10A of the intermediate transfer member 10. (Illustrated).

  When the image forming surface 10A of the intermediate transfer member 10 is cleaned in the cleaning unit 38, the intermediate transfer member 10 is cleaned while the intermediate transfer member 10 is heated to a predetermined temperature by the heater of the heating unit 44 from the back surface 10B side. The post-transfer residue is removed from the intermediate transfer member 10.

  The heating temperature (cleaning temperature) of the heating unit 44 provided corresponding to the cleaning unit 38 is determined according to the glass transition temperatures of the first release agent α and the second release agent β, similarly to the transfer temperature. . Specifically, the cleaning temperature (Tc) is higher than the glass transition temperature (Tg1) of the first release agent α and the glass transition temperature (Tg2) of the second release agent β (that is, Tc> Tg1>). Tt> Tg2), the heater disposed in the heating unit 44 is controlled by a system controller (not shown in FIG. 4, not shown in FIG. 9 and indicated by reference numeral 72).

  Next, the structures of the head 32A disposed in the second release agent droplet ejecting section 32 and the heads 34C, 34M, 34Y, and 34K disposed in the ink droplet ejecting section 34 will be described in detail. Since the structures of the heads 32A, 34C, 34M, 34Y, and 34K are common, the heads are represented by the reference numeral 50 in the following. For convenience of explanation, the case where the liquid ejected from the head is ink will be described. However, in the case of the head 32A disposed in the second release agent droplet ejection unit 32, “ink” is referred to as “second release mold”. It may be read as “agent β”.

  6A is a plan perspective view showing an example of the structure of the head 50, and FIG. 6B is an enlarged view of a part thereof. 6C is a plan perspective view showing another structure example of the head 50, and FIG. 7 is a cross-sectional view showing the three-dimensional configuration of the ink chamber unit (7-7 in FIGS. 6A and 6B). It is sectional drawing which follows a line.

  In order to increase the dot pitch formed on the intermediate transfer body 10, it is necessary to increase the nozzle pitch in the head 50. As shown in FIGS. 6A and 6B, the head 50 of this example includes a plurality of ink chamber units 53 including nozzles 51 that are ink droplet ejection holes and pressure chambers 52 corresponding to the nozzles 51. Are arranged in a staggered matrix (two-dimensionally), so that the projections are substantially arranged so as to be aligned along the longitudinal direction of the head (main scanning direction perpendicular to the conveyance direction of the intermediate transfer member). High nozzle density (projection nozzle pitch) is achieved.

  The form in which one or more nozzle rows are formed over a length corresponding to the entire width of the intermediate transfer member 10 in a direction substantially orthogonal to the conveyance direction of the intermediate transfer member 10 is not limited to this example. For example, instead of the configuration of FIG. 6A, as shown in FIG. 6C, short head blocks 50 ′ in which a plurality of nozzles 51 are two-dimensionally arranged are arranged in a staggered manner and joined together. A line head having a nozzle row having a length corresponding to the entire width of the intermediate transfer member 10 may be configured. Although not shown, a line head may be configured by arranging short heads in a line.

  The pressure chamber 52 provided corresponding to each nozzle 51 has a substantially square planar shape, and the nozzle 51 and the supply port 54 are provided at both corners on the diagonal line. Each pressure chamber 52 communicates with a common flow channel 55 through a supply port 54. The common channel 55 communicates with an ink supply tank (not shown in FIG. 7, not shown in FIG. 8 and indicated by reference numeral 60) as an ink supply source, and the ink supplied from the ink supply tank is the common channel 55 shown in FIG. Is distributed and supplied to each pressure chamber 52.

  A piezoelectric element 58 having an individual electrode 57 is joined to a diaphragm 56 that constitutes the top surface of the pressure chamber 52 and also serves as a common electrode. By applying a driving voltage to the individual electrode 57, the piezoelectric element 58 is Deformation causes ink to be ejected from the nozzle 51. When ink is ejected, new ink is supplied from the common channel 55 to the pressure chamber 52 through the supply port 54.

  In this example, the piezoelectric element 58 is applied as a means for generating ink ejection force ejected from the nozzles 51 provided in the head 50. However, a heater is provided in the pressure chamber 52, and the pressure of film boiling caused by heating of the heater is used. It is also possible to apply a thermal method that ejects ink.

  As shown in FIG. 6B, the ink chamber units 53 having such a structure are arranged in a fixed manner along a row direction along the main scanning direction and an oblique column direction having a constant angle θ that is not orthogonal to the main scanning direction. By arranging a large number of patterns in a lattice pattern, the high-density nozzle head of this example is realized.

  That is, with a structure in which a plurality of ink chamber units 53 are arranged at a constant pitch d along the direction of an angle θ with respect to the main scanning direction, the pitch P of the nozzles projected so as to be aligned in the main scanning direction is d × cos θ. Thus, in the main scanning direction, each nozzle 51 can be handled equivalently as a linear arrangement with a constant pitch P. With such a configuration, it is possible to realize a high-density nozzle configuration in which 2400 nozzle rows are projected per inch (2400 nozzles / inch) so as to be aligned in the main scanning direction.

  In the implementation of the present invention, the nozzle arrangement structure is not limited to the illustrated example, and various nozzle arrangement structures such as an arrangement structure having one nozzle row in the sub-scanning direction can be applied.

  Further, the application range of the present invention is not limited to the printing method using a line type head, and a short head that does not reach the length of the intermediate transfer body 10 in the width direction (main scanning direction) is scanned in the width direction of the intermediate transfer body 10. Then, printing in the width direction is performed, and when printing in the width direction is completed once, the intermediate transfer body 10 is moved by a predetermined amount in a direction (sub-scanning direction) orthogonal to the width direction, and the middle of the next printing area A serial method may be applied in which printing is performed in the width direction of the transfer body 10 and printing is performed over the entire printing area of the intermediate transfer body 10 by repeating this operation.

  FIG. 8 is a schematic diagram illustrating a configuration of an ink supply system in the inkjet recording apparatus 100. The processing liquid supply system has the same configuration as that of the ink supply system.

  The ink supply tank 60 is a base tank that supplies ink to the head 50, and is included in the liquid storage / loading unit (not shown) described above. The ink supply tank 60 includes a system that replenishes ink from a replenishment port (not shown) and a cartridge system that replaces the entire tank when the remaining amount of ink is low. A cartridge system is suitable for changing the ink type according to the intended use. In this case, it is preferable that the ink type information is identified by a barcode or the like, and ejection control is performed according to the ink type.

  As shown in FIG. 8, a filter 62 is provided between the ink supply tank 60 and the head 50 in order to remove foreign substances and bubbles. The filter mesh size is preferably equal to or smaller than the nozzle diameter (generally about 20 μm).

  Although not shown in FIG. 8, a configuration in which a sub tank is provided in the vicinity of the head 50 or integrally with the head 50 is also preferable. The sub-tank has a function of improving a damper effect and refill that prevents fluctuations in the internal pressure of the head.

  Further, the inkjet recording apparatus 100 is provided with a cap 64 as a means for preventing the nozzle 51 from drying or preventing an increase in ink viscosity near the nozzle, and a cleaning blade 66 as a means for cleaning the ink ejection surface of the head 50. Yes.

  The maintenance unit including the cap 64 and the cleaning blade 66 can be moved relative to the head 50 by a moving mechanism (not shown), and is moved from a predetermined retracted position to a maintenance position below the head 50 as necessary.

  The cap 64 is displaced up and down relatively with respect to the head 50 by an elevator mechanism (not shown). The cap 64 is raised to a predetermined raised position when the power is turned off or during printing standby, and is brought into close contact with the head 50, thereby covering the nozzle surface with the cap 64.

  During printing or standby, if the frequency of use of a specific nozzle 51 is reduced and ink is not ejected for a certain period of time, the ink solvent near the nozzle evaporates and the ink viscosity increases. In such a state, ink cannot be ejected from the nozzle 51 even if the piezoelectric element 58 operates.

  Before such a state is reached (within the range of viscosity that can be discharged by the operation of the piezoelectric element 58), the piezoelectric element 58 is operated, and a cap is formed to discharge the deteriorated ink (ink in the vicinity of the nozzle whose viscosity has increased). Preliminary ejection (purge, idle ejection, collar ejection, dummy ejection) is performed toward 64 (ink receiver).

  A mode in which preliminary ejection is performed by ejecting ink toward the intermediate transfer member 10 is also possible. For example, when a plurality of images are continuously formed, preliminary ejection can be performed between images. In particular, when a plurality of identical images are formed, the frequency of ink ejection at a specific nozzle is reduced, and the possibility of occurrence of ejection abnormality is increased, and preliminary ejection is performed between images for the specific nozzle. preferable.

  When preliminary discharge is performed on the intermediate transfer member 10, the transfer heating roller 36A is moved between the transfer heating roller 36A and the intermediate transfer member 10 so that ink from the preliminary discharge does not adhere to the transfer heating roller 36A. A predetermined clearance (for example, about 10 mm) may be provided.

  Further, when air bubbles are mixed in the ink in the head 50 (in the pressure chamber 52), the ink cannot be ejected from the nozzle even if the piezoelectric element 58 is operated. In such a case, the cap 64 is applied to the head 50, the ink in the pressure chamber 52 (ink mixed with bubbles) is removed by suction with the suction pump 67, and the suctioned and removed ink is sent to the recovery tank 68.

  In this suction operation, the deteriorated ink with increased viscosity (solidified) is sucked out when the ink is initially loaded into the head or when the ink is used after being stopped for a long time. Since the suction operation is performed on the entire ink in the pressure chamber 52, the amount of ink consumption increases. Therefore, it is preferable to perform preliminary ejection when the increase in ink viscosity is small.

  The cleaning blade 66 is made of an elastic member such as rubber, and can slide on the ink ejection surface of the head 50 by a blade moving mechanism (not shown). When ink droplets or foreign matter adhere to the ink ejection surface, the ink ejection surface is wiped by sliding the cleaning blade 66 on the ink ejection surface, and the ink ejection surface is cleaned.

  FIG. 9 is a principal block diagram showing the system configuration of the inkjet recording apparatus 100. The inkjet recording apparatus 100 includes a communication interface 70, a system controller 72, a memory 74, a motor driver 76, a heater driver 78, a print control unit 80, an image buffer memory 82, a head driver 84, and the like.

  The communication interface 70 is an interface unit that receives image data sent from the host computer 86. As the communication interface 70, a serial interface such as USB (Universal Serial Bus), IEEE 1394, Ethernet (registered trademark), a wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory (not shown) for speeding up communication may be mounted. The image data sent from the host computer 86 is taken into the ink jet recording apparatus 100 via the communication interface 70 and temporarily stored in the memory 74.

  The memory 74 is a storage unit that temporarily stores an image input via the communication interface 70, and data is read and written through the system controller 72. The memory 74 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The system controller 72 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire inkjet recording apparatus 100 according to a predetermined program, and also functions as an arithmetic device that performs various calculations. . That is, the system controller 72 controls each part such as the communication interface 70, the memory 74, the motor driver 76, the heater driver 78, etc., performs communication control with the host computer 86, read / write control of the memory 74, etc. A control signal for controlling the motor 88 and the heater 89 is generated.

  The memory 74 stores programs executed by the CPU of the system controller 72 and various data necessary for control. Note that the memory 74 may be a non-rewritable storage means or a rewritable storage means such as an EEPROM. The memory 74 is used as a temporary storage area for image data, and is also used as a program development area and a calculation work area for the CPU.

  The motor driver 76 is a driver that drives the motor 88 in accordance with instructions from the system controller 72. In FIG. 9, the motor (actuator) arranged in each part in the apparatus is represented by reference numeral 88. For example, the motor 88 shown in FIG. 9 includes a motor for driving the driving roller in the rollers 40A, 40B, and 36B in FIG. 4, a motor for a moving mechanism of the transfer heating roller 36A, and the like.

  The heater driver 78 is a driver that drives the heater 89 in accordance with an instruction from the system controller 72. In FIG. 9, a plurality of heaters provided in the inkjet recording apparatus 100 are represented by reference numeral 89. For example, the heater 89 shown in FIG. 9 includes the heater of the heating and drying unit 42 and the heating unit 44 shown in FIG. 4, the heater included in the transfer heating roller 36A, and the like.

  The transfer control unit 79 performs pressure control and temperature control of the transfer heating roller 36 </ b> A of the transfer unit 36 in accordance with an instruction from the system controller 72. For each type of recording medium 18 and each type of ink, an optimum pressing value and an optimum temperature value of the transfer heating roller 36A are obtained in advance, and are stored in a predetermined memory (for example, the memory 74) as a data table. And the information on the ink used are acquired, the pressure and temperature of the transfer heating roller 36A are controlled with reference to the memory.

  The print control unit 80 has a signal processing function for performing various processes and corrections for generating a print control signal from the image data in the memory 74 in accordance with the control of the system controller 72. The generated print data This is a control unit that supplies (dot data) to the head driver 84. Necessary signal processing is performed in the print control unit 80, and the ink of each head 50 disposed in the second release agent droplet ejecting unit 32 and the ink droplet ejecting unit 34 via the head driver 84 based on the image data. Control of the discharge amount and discharge timing of the droplet is performed. Thereby, a desired dot size and dot arrangement are realized.

  The print control unit 80 includes an image buffer memory 82, and image data, parameters, and other data are temporarily stored in the image buffer memory 82 when image data is processed in the print control unit 80. Also possible is an aspect in which the print controller 80 and the system controller 72 are integrated and configured with one processor.

  The first release agent application controller 81 controls the application amount of the first release agent α by the application roller 30A shown in FIG. In this example, the intermediate transfer body 10 and the application roller 30A can be contacted and separated from each other, and the application time of the application roller 30A to the intermediate transfer body 10 can be varied, so that the application amount of the first release agent α Control. The first release agent application unit 30 includes a sensor that detects the remaining amount of the first release agent α in the coating solution container, and the first release agent application control unit 81 is based on information obtained from the sensor. Then, the remaining amount of the first release agent α in the coating solution container is determined, and when the remaining amount is equal to or less than a predetermined amount, the fact is notified.

  The head driver 84 generates drive signals to be applied to the piezoelectric elements 58 of the respective heads 50 of the second release agent droplet ejection unit 32 and the ink droplet ejection unit 34 based on the image data given from the print control unit 80. And a drive circuit for driving the piezoelectric element 58 by applying the drive signal to the piezoelectric element 58. Note that the head driver 84 shown in FIG. 9 may include a feedback control system for keeping the driving condition of the head 50 constant.

  Data of an image to be printed is input from the outside via the communication interface 70 and stored in the memory 74. At this stage, RGB image data is stored in the memory 74.

  The image data stored in the memory 74 is sent to the print control unit 80 via the system controller 72, and is converted into dot data for each ink color and dot data of the second release agent β by the print control unit 80. . That is, the print control unit 80 performs a process of converting the input RGB image data into CMYK dot data of four colors and dot data of the second release agent β. The dot data generated by the print controller 80 is stored in the image buffer memory 82.

  Note that the primary image formed on the intermediate transfer body 10 must be a mirror image of the secondary image finally formed on the recording medium 18 in consideration of inversion during transfer. That is, the drive signal supplied to each head 50 is a drive signal corresponding to the mirror image, and the print control unit 80 needs to invert the input image.

  Various control programs are stored in the program storage unit 90, and the control programs are read and executed in accordance with instructions from the system controller 72. The program storage unit 90 may use a semiconductor memory such as a ROM or an EEPROM, or may use a magnetic disk or the like. An external interface may be provided and a memory card or PC card may be used. Of course, you may provide several recording media among these recording media. The program storage unit 90 may also be used as a recording means (not shown) for operating parameters.

  Next, the operation of the inkjet recording apparatus 100 configured as described above will be described.

  In the ink jet recording apparatus 100 of the present embodiment, the first release agent α is first formed on the entire surface of the intermediate transfer body 10 in the first release agent application unit 30 while the intermediate transfer body 10 is being transported in the intermediate transfer body transport direction. Thus, the first release layer 12 made of the first release agent α is formed on the entire surface of the intermediate transfer member 10 (FIG. 1A).

  Next, the second release agent β is ejected from the head 32 </ b> A of the second release agent ejection unit 32 corresponding to the dot formation position (position where the ink droplet is ejected) determined according to the image data. Dropped. Thereby, the 2nd mold release layer 14 which consists of 2nd mold release agent (beta) is formed on the 1st mold release layer 12 (FIG.1 (b)).

  At this time, it is preferable that the second release agent β is ejected not only at the same position as the dot formation position but also at a position adjacent to the dot formation position (see FIG. 3). As a result, the landing stability of ink droplets that are subsequently ejected is improved and the transferability is improved. In particular, an image with excellent edge quality can be obtained.

  After the second release agent β is ejected, ink droplets are ejected from the heads 34C, 34M, 34Y, 34K of the ink droplet ejecting section 34 at the dot formation position determined according to the image data. Is done. As described above, the second release layer 14 made of the second release agent β has already been formed at the position (dot formation position) where the ink droplets of each color are ejected. The ink droplets land on the second release layer 14 to form ink dots 16 (FIG. 1C).

  The ink image formed on the intermediate transfer member 10 is preliminarily heated in the heating and drying unit 42 as the intermediate transfer member 10 is conveyed, and the solvent component contained in the ink image is removed. Thereafter, the ink image formed on the intermediate transfer body 10 is transferred to the recording medium 18 while being heated to a predetermined temperature by the transfer heating roller 36 </ b> A having a heater in the transfer unit 36.

  At this time, the transfer temperature (Tt) is lower than the glass transition temperature (Tg1) of the first release agent α and higher than the glass transition temperature (Tg2) of the second release agent β (that is, Tg1> Tt> Tg2) Since the control is performed by the above-described system controller 72, the first release layer 12 made of the first release agent α is not in a fluid state at the time of transfer. Only the second release layer 14 made of the agent β is in a fluid state, and a part (or all) of the second release layer 14 is transferred to the recording medium 18 as shown in FIG.

  Further, after the transfer, the intermediate transfer member 10 is cleaned by the cleaning roller 38A of the cleaning unit 38 while being heated to a predetermined temperature by the heating unit 44 provided corresponding to the cleaning unit 38. At this time, the cleaning temperature (Tc) is higher than the glass transition temperature (Tg1) of the first release agent α and the glass transition temperature (Tg2) of the second release agent β (that is, Tc> Tg1> Tt>). Tg2) Since the control is performed by the system controller 72, not only the second release layer 14 made of the second release agent β but also the first release layer 12 made of the first release agent α is in a fluid state. Accordingly, the first release layer 12 made of the first release agent α together with the second release layer 14 made of the second release agent β can be easily removed from the intermediate transfer member 10.

  According to the ink jet recording apparatus 100 of the present embodiment, after the first release layer 12 made of the first release agent α is formed on the entire surface of the intermediate transfer body 10, the dot formation position determined according to the image data is set. On the other hand, the second release agent β and the ink droplet are sequentially ejected, and only the second release agent β is in a fluid state at the time of transfer, and the first release agent α is also in a fluid state at the time of cleaning. Control is performed. As a result, the first release agent α is not transferred to the recording medium 18, the texture of the non-image area on the recording medium 18 can be maintained, and the transferability can be improved. Further, the post-transfer residue on the intermediate transfer body 10 can be easily removed, and transfer defects can be prevented. As a result, a high-quality image can be realized.

(Second Embodiment)
Next, a second embodiment of the ink jet recording apparatus according to the present invention will be described. Hereinafter, description of parts common to the first embodiment will be omitted, and description will be made focusing on characteristic parts of the present embodiment.

  FIG. 10 is a schematic diagram illustrating a configuration example of an ink jet recording apparatus according to the second embodiment. 10, parts that are the same as or similar to those in FIG.

  The second embodiment is an electrorheological fluid (ER fluid) whose viscosity changes according to the electric field to which the first release agent α is applied, and the second release agent β is in a fluid state at a predetermined temperature. (For example, resin etc.).

As described above, the electrorheological fluid refers to a liquid in which the viscosity of the liquid changes instantaneously as compared with the state of no electric field when the liquid is placed in an electric field. There are two types of constituent materials for the electrorheological fluid, the particle dispersion type and the uniform type. The particle dispersion type is superior in terms of the magnitude of viscosity change and the wide selection of materials. There are also aqueous and non-aqueous particle dispersion types. In the aqueous particle dispersion type, particles such as silica, surface-treated silica, acrylic acid polymer, silicon polymer, starch, gelatin, and porous material are added in an aqueous solution or polar solvent. A distributed one is suitable. As the non-aqueous particle dispersion type, a dispersion in which silica, TiO ₂ , copper phthalocyanine, polyaniline, metal colloid, carbon powder, titanate, tartrate or the like is dispersed in an insulating organic liquid is suitable.

  As shown in FIG. 10, the inkjet recording apparatus 200 of the present embodiment is provided with an electric field applying unit 46 (46 </ b> A, 46 </ b> B) on the back surface 10 </ b> B side of the intermediate transfer body 10.

  The electric field applying unit 46 is provided over a region from the first release agent applying unit 30 and the second release agent droplet applying unit 32 to the transfer unit 36 toward the downstream side in the intermediate transfer member transport direction. After applying the first release agent α, a predetermined electric field is continuously applied from before the second release agent β is ejected until the image transfer to the recording medium 18 is completed, and after the transfer is completed, cleaning is started. The control is performed so that the application of the electric field is released by the time before.

  In addition, the electric field applying unit 46B located on the downstream side in the conveyance direction of the intermediate transfer member includes a heater, and also serves as the heating and drying unit 42 (see FIG. 4) in the first embodiment.

  Further, the transfer temperature (Tt) and the cleaning temperature (Tc) are controlled so that the glass transition temperature (Tg2) of the second release agent β is lower than the transfer temperature (Tt) and the cleaning temperature (Tc). That is, control is performed so as to satisfy the following expression Tt> Tg2 and Tc> Tg2.

  With this configuration, when the first release agent α is applied on the entire surface by the application roller 30A of the first release agent application unit 30, the first release layer 12 is formed on the intermediate transfer body 10 (FIG. 1 ( a)). When the region where the first release layer 12 is formed on the intermediate transfer member 10 moves toward the downstream side in the intermediate transfer member conveyance direction along with the conveyance of the intermediate transfer member 10, the electric field applying unit 46 (46A, 46B). Is applied, and the first release layer 12 made of the first release agent α is in a thickened state.

  Thereafter, similarly to the first embodiment, the second release agent β and the ink droplet are sequentially ejected to the dot formation position determined according to the image data. Then, the solvent component (liquid) contained in the ink image is removed while being preheated by the electric field applying unit 46B that also serves as the heating and drying unit, and then heated to a predetermined temperature by the transfer heating roller 36A of the transfer unit 36. The second release agent β is in a fluid state, and the ink image formed on the intermediate transfer body 10 is transferred to the recording medium 18. After the transfer, the application of the electric field is released, the first release layer 12 made of the first release agent α is in a reduced viscosity state, and the cleaning on the intermediate transfer body 10 is performed by the cleaning roller 38A of the cleaning unit 38. .

  According to this embodiment, at the time of transfer, the first release layer 12 made of the first release agent α does not decrease in viscosity, and the second release layer 14 made of the second release agent β is in a fluid state. Therefore, the first release agent α is not transferred to the recording medium 18, and the transferability can be improved while maintaining the texture of the non-image part of the recording medium 18. Further, since the first release layer 12 made of the first release agent α is in a low viscosity state during cleaning, the post-transfer residue on the intermediate transfer member 10 can be easily removed, resulting in transfer failure. Can be prevented. As a result, a high-quality image can be realized.

(Third embodiment)
Next, a third embodiment of the ink jet recording apparatus according to the present invention will be described. Hereinafter, description of parts common to the first and second embodiments will be omitted, and description will be made focusing on characteristic parts of the present embodiment.

  FIG. 11 is a schematic diagram illustrating a configuration example of an ink jet recording apparatus according to the third embodiment. In FIG. 11, parts that are the same as or similar to those in FIG. 4 or FIG.

  In the third embodiment, the first release agent α is a material (for example, resin) that is in a fluid state at a predetermined temperature, and the viscosity changes according to the electric field to which the second release agent β is applied. This is an embodiment that is a viscous fluid (ER fluid).

  As shown in FIG. 11, the inkjet recording apparatus 300 of the present embodiment is provided with an electric field applying unit 46 (46 </ b> A, 46 </ b> B) on the back surface 10 </ b> B side of the intermediate transfer body 10.

  The electric field applying unit 46 is provided over a region from between the second release agent droplet ejecting unit 32 and the ink droplet ejecting unit 34 to immediately downstream of the transfer unit 36 toward the downstream side in the intermediate transfer body conveyance direction. After the droplet release agent β is ejected, the electric field is continuously applied from before the ink droplet is ejected until the transfer is started, and when the transfer is started, the application of the electric field is canceled. Is called.

  Further, in the ink jet recording apparatus 300 of the present embodiment, a heating unit 44 corresponding to the cleaning unit 38 is provided on the back surface 10B side of the intermediate transfer body 10 as in the first embodiment.

  Further, the transfer temperature (Tt) and the cleaning temperature (Tc) are controlled so that the glass transition temperature (Tg1) of the first release agent α is higher than the transfer temperature (Tt) and lower than the cleaning temperature (Tc). (Ie, Tc> Tg1> Tt).

  With this configuration, when the first release agent α is applied on the entire surface by the application roller 30A of the first release agent application unit 30, the first release layer 12 is formed on the intermediate transfer body 10 (FIG. 1 ( a)). Thereafter, when the second release agent β is ejected to the dot formation position determined according to the image data as the intermediate transfer body 10 is conveyed, it is applied from the electric field applying unit 46 (46A). Due to the electric field, the second release layer 14 made of the second release agent β is in a thickened state.

  Before the ink droplet is ejected, by thickening the second release layer 14 made of the second release agent β, the ink droplet that has landed on the second release layer 14 becomes the second release layer. By entering inside 14, it is possible to prevent a phenomenon in which ink droplets are not transferred to the recording medium 18 during transfer.

  After the second release agent β is ejected, ink droplets are ejected in the same manner as in the first embodiment. Thereafter, as the intermediate transfer member 10 is conveyed, the application of the electric field to the intermediate transfer member 10 by the electric field applying unit 46 is released immediately before the transfer unit 36, and the second release layer 14 made of the second release agent β is released. The viscosity is reduced. Then, the ink image formed on the intermediate transfer body 10 is transferred to the recording medium 18 by being heated to a predetermined temperature by the transfer heating roller 36A of the transfer unit 36. At this time, the first release layer 12 made of the first release agent α is in a non-flowing state. Thereafter, the first release layer 12 made of the first release agent α is heated to a predetermined temperature by the heating unit 44, and the intermediate transfer member 10 is cleaned by the cleaning roller 38A of the cleaning unit 38. .

  According to the present embodiment, at the time of transfer, the first release layer 12 made of the first release agent α is not in a fluid state, and the second release layer 14 made of the second release agent β has a reduced viscosity. Therefore, the first release agent α is not transferred to the recording medium 18, and the transferability can be improved while maintaining the texture of the non-image portion of the recording medium 18. Further, at the time of cleaning, the first release layer 12 made of the first release agent α is in a fluid state, so that the post-transfer residue on the intermediate transfer body 10 can be easily removed, and transfer defects are prevented. be able to. As a result, a high-quality image can be realized.

  Although the ink jet recording apparatus and the recording method of the present invention have been described in detail above, the present invention is not limited to the above examples, and various improvements and modifications can be made without departing from the spirit of the present invention. Of course it is good.

Explanatory drawing which showed the outline | summary of the inkjet recording method based on this invention Explanatory drawing which showed the outline | summary of the inkjet recording method based on this invention Explanatory drawing which showed the aspect which drops a 2nd mold release agent to the outline part of an image part Explanatory drawing which showed the outline of the inkjet recording device which concerns on 1st Embodiment. FIG. 3 is a plan view of a main part around a printing unit of the ink jet recording apparatus according to the first embodiment. Plane perspective view showing structural example of head Sectional view along line 7-7 in FIG. 1 is a schematic diagram illustrating a configuration of an ink supply system of an ink jet recording apparatus according to a first embodiment. 1 is a principal block diagram showing a system configuration of an ink jet recording apparatus according to a first embodiment. Explanatory drawing which showed the outline of the inkjet recording device which concerns on 2nd Embodiment. Explanatory drawing which showed the outline of the inkjet recording device which concerns on 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Intermediate transfer body, 12 ... 1st mold release layer, 14 ... 2nd mold release layer, 16 ... Ink dot, 18 ... Recording medium, 20 ... Cleaner, 22 ... Ink droplet, 24 ... Image part, 26 ... Contour , 30... 1st release agent application unit, 32... 2nd release agent droplet ejection unit, 34... Ink ejection unit, 36... Transfer unit, 38 .. cleaning unit, 42. , 50 ... head, 51 ... nozzle, 80 ... system controller, 100, 200, 300 ... inkjet recording apparatus

Claims (11)

A first release agent applying means for applying a first release agent that melts at a predetermined temperature on the entire surface of the intermediate transfer member;
The second melted at a temperature lower than that of the first release agent at the same position as the dot formation position determined in accordance with the image data on the intermediate transfer body to which the first release agent has been applied. A second release agent droplet ejecting means for ejecting the release agent;
An ink droplet ejecting means for ejecting an ink droplet to a dot formation position on the intermediate transfer body on which the second release agent is deposited;
Transfer means for transferring an image formed on the intermediate transfer member to a recording medium;
Cleaning means for cleaning the intermediate transfer member;
Heating means for heating the intermediate transfer member;
When the glass transition temperature of the first mold release agent is Tg1, the glass transition temperature of the second mold release agent is Tg2, the temperature at the time of transfer is Tt, and the temperature at the time of cleaning is Tc, the following formula Tc>Tg1> Tt Control means for controlling the heating means so as to satisfy> Tg2,
An ink jet recording apparatus comprising: A first release agent applying means for applying a first release agent that is an electrorheological fluid to the entire surface of the intermediate transfer member;
Secondly, a second release agent that melts at a predetermined temperature is applied to the same position as the dot formation position determined according to the image data on the intermediate transfer body to which the first release agent is applied. Release agent droplet ejection means;
An ink droplet ejecting means for ejecting an ink droplet to a dot formation position on the intermediate transfer body on which the second release agent is deposited;
Transfer means for transferring an image formed on the intermediate transfer member to a recording medium;
Cleaning means for cleaning the intermediate transfer member;
Heating means for heating the intermediate transfer member;
An electric field applying means for applying an electric field to the intermediate transfer member;
When the glass transition temperature of the second release agent is Tg, the temperature at the time of transfer is Tt, and the temperature at the time of cleaning is Tc, the heating means is controlled to satisfy the following formula: Tt> Tg and Tc> Tg First control means for
After the application of the first release agent, an electric field is continuously applied to the intermediate transfer body until the transfer is completed from before the second release agent is ejected, and cleaning is started after the transfer is completed. Second control means for controlling the electric field applying means so as to cancel the application of the electric field by
An ink jet recording apparatus comprising: A first release agent applying means for applying a first release agent that melts at a predetermined temperature on the entire surface of the intermediate transfer member;
A second release agent that ejects a second release agent, which is an electrorheological fluid, at the same position as a dot formation position determined according to image data on the intermediate transfer body to which the first release agent has been applied. Mold spraying means;
An ink droplet ejecting means for ejecting an ink droplet to a dot formation position on the intermediate transfer body on which the second release agent is deposited;
Transfer means for transferring an image formed on the intermediate transfer member to a recording medium;
Cleaning means for cleaning the intermediate transfer member;
Heating means for heating the intermediate transfer member;
An electric field applying means for applying an electric field to the intermediate transfer member;
First control for controlling the heating means so as to satisfy the following formula: Tc>Tg> Tt, where Tg is the glass transition temperature of the first release agent, Tt is the temperature at the time of transfer, and Tc is the temperature at the time of cleaning. Means,
After droplet ejection of the second release agent, an electric field is continuously applied to the intermediate transfer body from before the ink droplet is ejected until transfer is started. Second control means for controlling the electric field applying means so that the application is released;
An ink jet recording apparatus comprising:   2. The second release agent droplet ejection unit ejects the second release agent not only at the same position as the dot formation position but also at a position adjacent to the dot formation position. The ink jet recording apparatus according to claim 3.   5. The ink jet recording apparatus according to claim 1, wherein each of the second release agent droplet ejecting unit and the ink droplet ejecting unit includes an inkjet head having the same resolution. .   When the contact angle of the second release agent with respect to the intermediate transfer member is θ1, and the contact angle of the second release agent with respect to the release layer formed by the first release agent is θ2, the following equation θ1> The inkjet recording apparatus according to claim 1, wherein the relationship θ2 is satisfied.   The second release agent contains a component that aggregates the coloring material of the ink droplets or a component that thickens the ink droplets after the ink droplets have landed. Item 7. The ink jet recording apparatus according to any one of Items 6. 8. The difference in storage elastic modulus at the transfer temperature between the first release agent and the second release agent is 10 ² [Pa] or more, 8. Inkjet recording apparatus. Providing a first release agent that melts at a predetermined temperature on the entire surface of the intermediate transfer member;
The second melted at a temperature lower than that of the first release agent at the same position as the dot formation position determined in accordance with the image data on the intermediate transfer body to which the first release agent has been applied. A step of ejecting a release agent;
Ejecting ink droplets onto dot forming positions on the intermediate transfer body on which the second release agent has been ejected;
Transferring the image formed on the intermediate transfer member to a recording medium;
Cleaning the intermediate transfer member;
When the glass transition temperature of the first mold release agent is Tg1, the glass transition temperature of the second mold release agent is Tg2, the temperature at the time of transfer is Tt, and the temperature at the time of cleaning is Tc, the following formula Tc>Tg1> Tt Controlling to satisfy>Tg2;
An ink jet recording method comprising: Applying a first release agent that is an electrorheological fluid to the entire surface of the intermediate transfer member;
A step of ejecting a second release agent that melts at a predetermined temperature at the same position as a dot formation position determined according to image data on the intermediate transfer body to which the first release agent has been applied; ,
Ejecting ink droplets onto dot forming positions on the intermediate transfer body on which the second release agent has been ejected;
Transferring the image formed on the intermediate transfer member to a recording medium;
Cleaning the intermediate transfer member;
A step of controlling the second release agent to have a glass transition temperature Tg, a transfer temperature Tt, and a cleaning temperature Tc, so that the following formulas Tt> Tg and Tc> Tg are satisfied:
After the application of the first release agent, an electric field is continuously applied to the intermediate transfer body until the transfer is completed from before the second release agent is ejected, and cleaning is started after the transfer is completed. Controlling to release the application of the electric field by
An ink jet recording method comprising: Providing a first release agent that melts at a predetermined temperature on the entire surface of the intermediate transfer member;
Droplet ejection of the second release agent, which is an electrorheological fluid, at the same position as the dot formation position determined according to the image data on the intermediate transfer body to which the first release agent has been applied;
Ejecting ink droplets onto dot forming positions on the intermediate transfer body on which the second release agent has been ejected;
Transferring the image formed on the intermediate transfer member to a recording medium;
Cleaning the intermediate transfer member;
Controlling the glass transition temperature of the first release agent to be Tg, the temperature at the time of transfer to be Tt, and the temperature at the time of cleaning to be Tc, and satisfying the following formula: Tc>Tg>Tt;
After the second release agent is deposited, the electric field is continuously applied to the intermediate transfer body immediately before the ink droplet is ejected and immediately before the transfer is started. Controlling to release the application of the electric field;
An ink jet recording method comprising:

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