JP2009045794A - Image forming method and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent ink droplets from migrating on an intermediate transfer body, to attain a predetermined spreading ratio, and to make it possible to form high quality images without landing interference. <P>SOLUTION: The above problem is solved by providing an image forming method including a step for discharging droplets such that a plurality of first ink droplets are arranged spaced from each others so as not to contact with each other along a main scanning direction (a direction perpendicular to the conveying direction of the intermediate transfer body) on the intermediate transfer body, a step for discharging first processing droplets to the discharge positions of the plurality of first ink droplets, a step for discharging the droplets such that the second ink droplets are arranged among the plurality of first ink droplets after the step in which the first ink droplets and the first processing droplets are discharged, a step for discharging second processing droplets to the discharge positions of the second ink droplets after the step in which the first ink droplets and the first processing droplets are discharged, a step for removing solvent components of the ink and the processing liquids on the intermediate transfer body, and a step for transferring images from the intermediate transfer body to a recording medium. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming method and an image forming apparatus, and in particular, forms an ink image composed of ink aggregates (color material aggregates) by mixing and reacting ink and processing liquid on an intermediate transfer body, and The present invention relates to an image forming method and an image forming apparatus for transferring an ink image formed on a recording medium.

  At present, an inkjet recording apparatus is suitably used as a general-purpose image forming apparatus that outputs an image photographed by a digital camera, a duplicate image of a printed matter, or the like. The ink jet recording apparatus can use various recording media such as resin sheets and metal sheets as well as paper. As a recent trend of ink jet recording apparatuses, there is a high demand for outputting high quality images regardless of the type of recording medium.

  However, when a recording medium having permeability (for example, plain paper or recycled paper) is used, “feathering” that is ink bleeding along the fibers of the recording medium occurs. In addition, when using a recording medium having non-permeability or a recording medium having low permeability that has a very low permeation rate, the ink ejected onto the recording medium flows without being absorbed by the recording medium. Or a “beading” in which adjacent ink dots are mixed with each other. Furthermore, in the case of forming a color image, “bleeding” occurs in which border portions of overlapping colors are blurred.

  As a method to prevent feathering that occurs when using a recording medium with penetrability, an image is formed on the intermediate transfer member, and the image formed on the intermediate transfer member is recorded after temporarily fixing the image to the intermediate transfer member. A transfer method for transferring to a medium has been proposed.

  In the transfer method, since an image is formed on an intermediate transfer member having non-penetration, feathering due to ink penetration does not occur on the intermediate transfer member. Further, when the image is temporarily fixed on the intermediate transfer member, the ink droplets are dried and thickened, so that the ink can be prevented from penetrating into the recording medium after being transferred to the recording medium. Feathering that spreads ink along the fiber is also suppressed.

  On the other hand, when adjacent ink droplets contact each other on the intermediate transfer member, landing interference may occur. FIG. 9A shows a state where two ink droplets 200 and ink droplets 202 forming at least two dots arranged so as to contact each other have landed on the intermediate transfer member 204. As shown in FIG. 9A, since the ink droplets 200 and 202 forming two dots exist in the atmosphere, meniscuses (interfaces between the atmosphere and the ink droplets) 206 and 208 are formed around the ink droplets. Exists. When the meniscus 206 of the ink droplet 200 and the meniscus 208 of the ink droplet 202 come into contact with each other (in FIG. 9, the contact portion of the meniscus is indicated by reference numeral 210), the ink droplet 200 and the ink droplet 202 have surface tension (surface As a result, the ink droplet 200 and the ink droplet 202 are united on the intermediate transfer member 204. FIG. 9B shows an ink droplet 212 formed by combining the ink droplet 200 and the ink droplet 202 shown in FIG. 9A.

  As a method for avoiding such image degradation due to landing interference, a so-called two-component image forming method is proposed in which ink and a processing liquid are reacted on the intermediate transfer member to promote fixing of the ink on the intermediate transfer member. ing.

  For example, in the case of using a pigment-based ink in which a pigment is dispersed as a coloring material (coloring material) in a solvent, an intermediate transfer body is provided with a treatment liquid 213 that develops aggregation of the pigment contained in the ink prior to the ink droplet 212. Then, the ink droplet 212 is applied according to the image data (see FIG. 10A).

  When the processing liquid 213 and the ink droplet 212 come into contact with and mix on the intermediate transfer body 214, the processing liquid 213 and the ink droplet 212 react on the intermediate transfer body 214 as shown in FIG. Aggregates (color material aggregates) 216 are formed. FIG. 10C illustrates a state in which the reaction between the ink droplet 212 and the treatment liquid 213 is completed and dots are formed by the ink aggregate 216.

  In this manner, by causing ink droplets to rapidly aggregate (cur) simultaneously with landing on the intermediate transfer member, occurrence of phenomena such as repelling, beading, and bleeding can be prevented. The above-described two-component image forming method is particularly effective when a non-permeable medium is used.

In Patent Document 1, as a method of forming an image in which repelling, beading, and bleeding are suppressed on an intermediate transfer member, a first material for reducing the fluidity of ink is applied to a transfer drum (intermediate transfer member). An ink jet recording method and an ink jet recording apparatus that apply a colored ink liquid to the first material, apply a second material containing a resin, and transfer an ink image formed on the intermediate transfer member to a recording medium. Proposed.
JP 2005-170036 A

  However, in the two-liquid image forming method according to the related art described with reference to FIGS. 10A to 10C, when the amount of the processing liquid is too small with respect to the ink droplet amount, the ink droplet is not removed. The effect of aggregating cannot be sufficiently exhibited. In addition, when the amount of the treatment liquid is excessive with respect to the ink droplet amount, the aggregation reaction is completed before the ink droplets are sufficiently spread. Cannot be obtained, and a predetermined contact area between the ink aggregate and the intermediate transfer member cannot be ensured.

  Furthermore, since the aggregation reaction is completed before the ink droplets reach the intermediate transfer body, the adhesive force between the ink aggregate and the intermediate transfer body is not sufficient, and the ink aggregate (dot) An unstable adhesion state (for example, a state of floating in the processing solution) is caused. That is, when the amount of the treatment liquid is excessive with respect to the ink droplet amount, image disturbance due to dot movement and dot size abnormality occurs.

  In the invention described in Patent Document 1, as a first material for reducing the fluidity of ink, a material that agglomerates ink by contact with ink is applied onto an ink jet head after being applied onto an image transfer roller by an application roller. Since the ink is applied, the ink droplets land in the liquid of the first material, and at the same time, the aggregation reaction occurs. The first material is present on the entire surface of the transfer drum, so that the color material moves and the image is disturbed. The problem occurs.

  In addition, the ink droplets do not spread in the first material due to the cohesive force of the ink, a dot of a desired size is not formed, and a preferable solid image cannot be formed, or the line width is narrower than the desired width, A phenomenon in which an image is separated into a plurality of lines occurs, and a reduction in spreading rate due to the cohesive force of ink and movement of color materials (dots) are observed.

  Further, when the thickness of the first material is 1 μm or less, when ink droplets are ejected so as to overlap adjacent droplet ejection points, landing interference occurs between adjacent ink droplets, and the combined ink There is a phenomenon in which the droplet shape is changed and the dot shape is disturbed (see FIG. 9B).

  The present invention has been made in view of such circumstances, and an ink and a treatment liquid are respectively applied to an intermediate transfer member to form an image composed of an ink aggregate (color material aggregate). In the transfer system that transfers the image formed on the recording medium, the ink droplets are prevented from moving on the intermediate transfer body, achieving the desired spread ratio, and forming high-quality images without landing interference It is an object of the present invention to provide an image forming method and an image forming apparatus.

  In order to achieve the above object, the image forming method according to the present invention applies an ink containing a color material and a treatment liquid for aggregating the color material to the intermediate transfer body while conveying the intermediate transfer body. An image forming method for forming an image comprising the color material aggregate on the intermediate transfer member, and transferring the image formed on the intermediate transfer member to a recording medium, the method comprising: The plurality of first ink droplets are arranged with respect to the intermediate transfer member such that the plurality of first ink droplets are spaced apart from each other along a direction perpendicular to the conveyance direction of the intermediate transfer member. A first ink droplet ejection step for ejecting the first treatment liquid droplets to the droplet ejection positions of the plurality of first ink droplets on the intermediate transfer member, respectively. And the first ink droplet ejection step and the first treatment liquid droplet ejection step are performed. After that, the second ink droplets are applied to the intermediate transfer member so that the second ink droplets are disposed between the plurality of first ink droplets that are spaced apart on the intermediate transfer member. After the second ink droplet ejecting step, the first ink droplet ejecting step, and the first treatment liquid droplet ejecting step are performed, the droplet ejection position of the second ink droplet on the intermediate transfer member is A second treatment liquid droplet ejection step for ejecting the second treatment droplet, a solvent removal step for removing the ink and the solvent component of the treatment liquid on the intermediate transfer body, and the recording medium from the intermediate transfer body And a transfer step of transferring an image to the image.

  According to the present invention, ink droplets (first and second ink droplets) ejected on a position adjacent to the intermediate transfer member in a direction perpendicular to the conveyance direction of the intermediate transfer member are one ink liquid. After the droplets (first ink droplets) aggregate due to the mixing reaction with the treatment droplets, the other ink droplet (second ink droplet) is ejected, so these ink droplets contact each other. Even if they are not united, landing interference is prevented. Further, since the treatment droplet is ejected to the same position as each ink droplet, each ink droplet spreads to a predetermined size without moving the coloring material, and a desired spreading rate is ensured. be able to. As a result, high-quality image formation is possible.

  In the present invention, it is preferable that each ink droplet ejection step is performed before the corresponding treatment liquid droplet ejection step. That is, a preferable order is the first ink droplet ejection step, the first treatment liquid droplet ejection step, the second ink droplet ejection step, and the second treatment liquid step. Each ink droplet spreads to a predetermined size on the intermediate transfer member, and a desired spreading rate can be ensured.

  The “spreading rate” is defined as the ratio of the diameter of the dot fixed on the recording medium to the diameter when the ejection volume of the ink droplet is converted to a true sphere.

  Also, a cooling step for cooling the intermediate transfer member and the recording medium after the transfer step, a peeling step for peeling the recording medium from the intermediate transfer member, a cleaning step for cleaning the intermediate transfer member after the peeling step, and a peeling step from the intermediate transfer member. And a fixing step of heating the recording medium in order to fix the image on the recording medium.

  According to a second aspect of the present invention, there is provided the image forming method according to the first aspect, wherein after the first ink droplet ejection step and the first processing liquid droplet ejection step are performed, the intermediate transfer member is provided. The third ink droplets are applied to the intermediate transfer member so that the third ink droplets are arranged at positions adjacent to the transport direction of the intermediate transfer member of the first ink droplets arranged above. After the third ink droplet ejecting step, the first ink droplet ejecting step, and the first treatment liquid droplet ejecting step are performed, the droplets are ejected at the third ink droplet ejection position on the intermediate transfer body. And a third treatment liquid droplet ejection step for ejecting the third treatment droplet.

  According to the second aspect of the present invention, ink droplets that are ejected not only in a direction perpendicular to the conveyance direction of the intermediate transfer member but also in a position adjacent to the conveyance direction of the intermediate transfer member (first and third). As for the ink droplet, the other ink droplet (third ink droplet) is ejected after one ink droplet (first ink droplet) is aggregated by the mixing reaction with the processing droplet. Therefore, even if these ink droplets come into contact with each other, landing interference is prevented without being united. Further, since the treatment droplet is ejected to the same position as each ink droplet, each ink droplet spreads to a predetermined size without moving the coloring material, and a desired spreading rate is ensured. be able to. As a result, a higher quality image can be formed.

  The invention according to claim 3 relates to an aspect of the image forming method according to claim 1 or 2, and after the second ink droplet ejection step and the second processing liquid droplet ejection step are performed, The fourth ink droplet is disposed on the intermediate transfer member so that the fourth ink droplet is disposed at a position adjacent to the transport direction of the second ink droplet disposed on the intermediate transfer member. After the fourth ink droplet ejection step for ejecting ink droplets, the second ink droplet ejection step, and the second processing liquid droplet ejection step, the fourth ink droplets on the intermediate transfer member And a fourth treatment liquid droplet ejecting step of ejecting the fourth treatment droplet to the droplet ejection position.

  According to the third aspect of the present invention, ink droplets that are ejected not only in a direction perpendicular to the transport direction of the intermediate transfer member but also in a position adjacent to the transport direction of the intermediate transfer member (second and fourth). As for the ink droplets, one ink droplet (second ink droplet) is aggregated by the mixing reaction with the processing droplet, and then the other ink droplet (fourth ink droplet) is ejected. Therefore, even if these ink droplets come into contact with each other, landing interference is prevented without being united. Further, since the treatment droplet is ejected to the same position as each ink droplet, each ink droplet spreads to a predetermined size without moving the coloring material, and a desired spreading rate is ensured. be able to. As a result, a higher quality image can be formed.

  The invention according to claim 4 relates to an aspect of the image forming method according to any one of claims 1 to 3, wherein the ink is a liquid containing an acid polymer that aggregates at a pH of less than 5. The treatment liquid is a liquid having a pH of less than 5.

  According to the fourth aspect of the present invention, the polymer fine particles undergo a polarity conversion, an attractive force is generated between the colorant particles contained in the ink, the cohesive force is increased, and the ink droplet aggregation rate is increased. Ink droplets can aggregate quickly.

  In order to achieve the above object, the invention according to claim 5 provides an apparatus invention. That is, the image forming apparatus according to the invention of claim 5 applies the ink containing the color material and the treatment liquid for aggregating the color material to the intermediate transfer body while conveying the intermediate transfer body. An image forming apparatus for forming an image composed of an aggregate of the color materials on the intermediate transfer member, and transferring the image formed on the intermediate transfer member to a recording medium, wherein the image is formed on the intermediate transfer member. The plurality of first ink droplets are arranged on the intermediate transfer member so that the plurality of first ink droplets are spaced apart from each other along a direction perpendicular to the conveyance direction of the intermediate transfer member. First ink droplet ejecting means for ejecting droplets, and first treatment liquid droplet ejecting means for ejecting first processing droplets to the droplet ejection positions of the plurality of first ink droplets on the intermediate transfer member, respectively The intermediate portion of the first ink droplet ejection unit and the first treatment liquid droplet ejection unit. The second ink droplets are arranged with respect to the intermediate transfer member so that the second ink droplets are arranged between the plurality of first ink droplets provided on the downstream side of the transfer body in the transport direction and spaced apart on the intermediate transfer member. A second ink droplet ejecting unit that ejects the second ink droplet; a first ink droplet ejecting unit; and a first processing liquid droplet ejecting unit that are provided on the downstream side in the transport direction of the intermediate transfer member. Second treatment liquid droplet ejecting means for ejecting the second treatment liquid droplet to the droplet ejection position of the second ink droplet on the transfer body, the ink on the intermediate transfer body, and the solvent component of the treatment liquid And a transfer means for transferring an image from the intermediate transfer member to the recording medium.

  In the present invention, the order in which the first ink droplet ejection unit and the first treatment liquid droplet ejection unit are arranged is not particularly limited with respect to the conveyance direction of the intermediate transfer member, but droplet ejection is performed by the first ink droplet ejection unit. From the viewpoint of securing the spreading rate of the first ink droplets, it is preferable that the first ink droplet ejection unit is disposed upstream of the first processing liquid droplet ejection unit. The same applies to the order in which the second ink droplet ejection unit and the second processing liquid droplet ejection unit are arranged, and it is preferable that the second ink droplet ejection unit is disposed upstream of the second process liquid droplet ejection unit. .

  The solvent removing means may be contact-type absorbing means that contacts the intermediate transfer member and absorbs and removes the solvent component on the intermediate transfer member. Alternatively, the solvent removing means may contact the intermediate transfer member without contact with the intermediate transfer member. A non-contact type means for removing the solvent component may be applied.

  In addition, it is preferable that after the solvent on the intermediate transfer member is removed by the solvent removing unit, a preheating unit that preheats the intermediate transfer member before the transfer by the transfer unit is provided. An embodiment in which the temperature of the intermediate transfer member and the recording medium is made lower than the softening point temperature of the polymer fine particles by preheating means is preferable.

  A cooling means for cooling the intermediate transfer body and the recording medium after transfer; a peeling means for peeling the recording medium from the intermediate transfer body; and a cleaning means for cleaning the intermediate transfer body after peeling the recording medium from the intermediate transfer body; An embodiment including a fixing unit that heats the recording medium to fix the image on the recording medium peeled from the intermediate transfer member is preferable.

  According to the present invention, ink droplets (first and second ink droplets) ejected on a position adjacent to the intermediate transfer member in a direction perpendicular to the conveyance direction of the intermediate transfer member are one ink liquid. After the droplets (first ink droplets) aggregate due to the mixing reaction with the treatment droplets, the other ink droplet (second ink droplet) is ejected, so these ink droplets contact each other. Even if they are not united, landing interference is prevented. Further, since the treatment droplet is ejected to the same position as each ink droplet, each ink droplet spreads to a predetermined size without moving the coloring material, and a desired spreading rate is ensured. be able to. As a result, high-quality image formation is possible.

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

(First embodiment)
[Inkjet recording device]
FIG. 1 is a schematic configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the inkjet recording apparatus 10 of the present embodiment includes a printing unit 16 that applies ink and processing liquid to the intermediate transfer body 12, and solvent components of the ink and processing liquid on the intermediate transfer body 12. Is mainly composed of a solvent removing unit 18 that removes the toner and a transfer unit 20 that transfers an image from the intermediate transfer body 12 to the recording medium 14.

  Although the configuration of the printing unit 16 will be described in detail later, the inkjet unit ejects ink of each color of cyan (C), magenta (M), yellow (Y), and black (K) to the printing unit 16. A plurality of heads (hereinafter referred to as “ink heads”) are provided, and an ink jet type liquid discharge head (hereinafter referred to as “processing liquid head”) that discharges a processing liquid (coloring material aggregation liquid) that aggregates ink is provided. It is provided corresponding to each ink head. Hereinafter, the ink head and the treatment liquid head may be collectively referred to simply as “head”.

  Each head is disposed at a position opposed to the image forming surface 12A of the intermediate transfer body 12, and a liquid (ink or processing liquid) corresponding to the intermediate transfer body 12 from each head is formed into droplets. Is discharged.

  The ink and treatment liquid used in this example will be described in detail later. In this example, an ink containing a pigment (pigment ink) as a coloring material (coloring material) corresponding to each color and a coloring material contained in the ink are used. A treatment liquid containing a component to be aggregated is used.

  An endless belt is applied to the intermediate transfer member 12 shown in FIG. 1, and the intermediate transfer member (endless belt) 12 is wound around a plurality of stretching rollers (seven stretching rollers 22A to 22G are shown in FIG. 1). The intermediate transfer body 12 has an applied structure, and the power of a motor (not shown in FIG. 1 and indicated by reference numeral 88 in FIG. 5) is transmitted to at least one of the stretching rollers 22A to 22G. In FIG. 1, it is driven in the counterclockwise direction (the direction indicated by arrow A in FIG. 1).

  The intermediate transfer member (endless belt) 12 is made of resin, metal, rubber, or the like in an image forming area (not shown) on which at least a primary image is formed on a surface (image forming surface) 12A facing the printing unit 16. It has non-permeability that prevents ink droplets from penetrating. Further, at least the image forming area of the intermediate transfer body 12 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 12A of the intermediate transfer body 12 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.

  Further, it is preferable that the surface tension of the surface layer of the intermediate transfer body 12 is 10 mN / m or more and 40 mN / m or less. When the surface tension of the surface layer of the intermediate transfer body 12 is 40 mN / m or more, the surface tension difference from the recording medium 14 onto which the primary image is transferred is eliminated (or extremely small), and the transferability of the ink aggregate is improved. Getting worse. Furthermore, when the surface tension of the surface layer of the intermediate transfer body 12 is 10 mN / m or less, the design freedom (selection range) of the surface layer of the intermediate transfer body 12 becomes narrow.

  FIG. 2 is a main part plan view showing the periphery of the printing unit 16 of the inkjet recording apparatus 10 shown in FIG. As shown in FIG. 2, the printing unit 16 includes cyan (C), magenta (M), yellow (Y), and black (K) inks arranged in order from the upstream side along the intermediate transfer member conveyance direction. A plurality of droplet ejecting sections 24 (24C, 24M, 24Y, 24K) corresponding to the plurality of ink heads 26 and the treatment liquid heads 28 are provided in each droplet ejecting section 24 along the conveyance direction of the intermediate transfer member. Are provided alternately.

  The droplet ejection unit 24 of this example is provided with two ink heads (first and second ink heads) 26A and 26B corresponding to the respective color inks, and processing liquid heads corresponding to the respective ink heads 26A and 26B. (First and second processing liquid heads) 28A and 28B are provided adjacent to the downstream side in the conveyance direction of the intermediate transfer member. Specifically, as shown in FIG. 2, the first ink head 26A, the first treatment liquid head 28A, the second ink head 26B, the second ink head 26A are sequentially arranged from the upstream side along the intermediate transfer member conveyance direction. A treatment liquid head 28B is disposed.

  The ink heads 26 (26A, 26B) and the treatment liquid heads 28 (28A, 28B) provided in each droplet ejecting section 24 (24C, 24M, 24Y, 24K) are respectively the maximum width of the image forming area in the intermediate transfer body 12. A full-line type in which a plurality of nozzles for discharging liquid droplets (not shown in FIG. 1, indicated by reference numeral 51 in FIG. 3) are arranged on the discharge surface over the entire width of the image forming area. It is a head. The heads 26 and 28 are fixedly installed so as to extend in a direction orthogonal to the intermediate transfer member conveyance direction.

  The ejection methods of the heads 26 and 28 are a method of ejecting liquid using the displacement of the piezoelectric element (piezoelectric method), a method of ejecting liquid using the thermal energy generated by the heating element (thermal method), and various other types. It is possible to apply a scheme.

  Each of the heads 26 and 28 in this example is a piezoelectric head, and a liquid (ink or processing liquid) in a pressure chamber provided inside the head is pressurized by displacement of the piezoelectric element, and liquid is discharged from a nozzle communicating with the pressure chamber. It is ejected as a drop.

  Each of the heads 26 and 28 is an intermediate transfer device in which short head blocks (head chips) less than the maximum width of the image forming area of the intermediate transfer body 12 are arranged in a staggered manner or connected in a line. A line-type head having a nozzle row having a length corresponding to the entire width of the body 12 may be configured.

  According to the configuration in which the full line type head having the nozzle row covering the entire width of the intermediate transfer body 12 is provided for each discharge liquid, the intermediate transfer body 12 and the printing unit 16 in the intermediate transfer body conveyance direction (sub-scanning direction). The primary image can be recorded in the image forming area of the intermediate transfer body 12 only by performing the operation of relatively moving the respective droplet ejecting portions 24 constituting the image forming unit 1 (that is, by one sub-scanning). As a result, high-speed printing is possible and printing productivity can be improved as compared with the case where a serial (shuttle) type head that reciprocates in the direction (main scanning direction) orthogonal to the intermediate transfer member conveyance direction is applied. it can.

  The scope of application of the present invention is not limited to the printing method using a line type head, and a short head that is less than the length of the intermediate transfer body 12 in the main scanning direction is scanned in the main scanning direction to perform printing in the main scanning direction. When the printing in one main scanning direction is completed, the intermediate transfer body 12 is moved by a predetermined amount in the sub-scanning direction to perform printing in the main scanning direction of the intermediate transfer body 12 in the next printing area. A serial method in which printing is performed over the entire printing area of the intermediate transfer body 12 by repeating the above may be applied.

  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.

  FIG. 3 is a configuration diagram showing an example of a nozzle arrangement structure of each head 26 and 28 arranged in the droplet ejection unit 24. In this example, for convenience of explanation, a case where the number of nozzles of each head 26, 28 is six will be described as an example. However, the number of nozzles is not limited to this example.

  As shown in FIG. 3, each head 26, 28 has a plurality of nozzles 51 in a staggered pattern in two rows along a direction (main scanning direction) orthogonal to the intermediate transfer member conveyance direction (sub-scanning direction). It is arranged. The nozzle arrangement structure of each head 26 and 28 is not limited to this example. For example, a structure having nozzle rows arranged in one row along the main scanning direction, or a plurality of nozzles are two-dimensionally (matrix-like). It is also possible to apply an ordered structure.

  The projection nozzle row 52 in which the nozzles 51 (51A, 51B) provided in the first and second ink heads 26A, 26B are projected in a row along the main scanning direction is projected onto the first ink head 26A. The nozzles 51 </ b> A provided and the nozzles 51 </ b> B provided in the second ink head 26 </ b> B are configured to be alternately arranged at equal intervals along the main scanning direction. That is, the first and second ink heads 26A and 26B are complementary to each other. For example, when forming the dot row 54 in the main scanning direction shown on the right side in FIG. Droplets are ejected from the nozzles 51 (51A, 51B) provided in the ink heads 26A, 26B.

In the present embodiment, in the projection nozzle row 52 composed of the nozzles 51 (51A, 51B) of the first and second ink heads 26A, 26B, the distance between the centers of the nozzles 51A, 51B adjacent in the main scanning direction ( Nozzle pitch) is N ₁ , the center-to-center distance (nozzle pitch) between nozzles 51A, 51A (or 51B, 51B) adjacent in the main scanning direction within the same head is N ₂ , and droplets are ejected from each nozzle 51A, 51B. When the diameter (dot diameter) of the dots formed on the intermediate transfer body 12 by the ink droplet is D, the relationship of the following formula N ₁ <D <N ₂ (= 2N ₁ ) is satisfied. That is, at least a part of dots formed by ink droplets ejected from the nozzles 51A and 51B adjacent in the main scanning direction in the projection nozzle array 52 as in the dot array 54 shown in FIG. In addition, the dots formed by the ink droplets ejected from the nozzles 51A, 51A (or 51B, 51B) adjacent in the main scanning direction within the same head do not overlap each other. The nozzle pitch and dot size (discharge droplet amount) of each nozzle 51 (51A, 51B) are determined.

  The first and second processing liquid heads 28A and 28B have the same configuration (including the nozzle arrangement structure) as the ink heads 26A and 26B arranged adjacent to the upstream side in the intermediate transfer member conveyance direction, respectively. That is, the nozzles 51 of the treatment liquid heads 28A and 28B are provided at the same position as the nozzles 51 of the ink heads 26A and 26B arranged adjacent to the upstream side in the intermediate transfer member conveyance direction.

  In the present embodiment, for example, when the dot row 54 shown on the right side of FIG. 3 is formed, the following droplet ejection order is performed. That is, while the intermediate transfer body 12 is being transported, first, when the image forming area (position where the dot row 54 is to be formed) on the intermediate transfer body 12 has moved to a position facing the first ink head 26A, the first transfer is performed. First ink droplets are ejected from the respective nozzles 51 of the ink head 26A, and a plurality of first ink droplets are formed on the intermediate transfer body 12 along a direction (main scanning direction) orthogonal to the intermediate transfer body conveyance direction. So that they are not in contact with each other. Subsequently, when the image forming area on the intermediate transfer body 12 moves to a position facing the first processing liquid head 28A, the same ejection as the plurality of first ink droplets spaced on the intermediate transfer body 12 is performed. A first processing droplet is ejected from each nozzle 51 of the first processing liquid head 28A to the droplet position. The plurality of first ink droplets spaced apart on the intermediate transfer body 12 are mixed and reacted with the first treatment droplets ejected at the same position, and the color material aggregates (dots) are formed on the intermediate transfer body 12. Formed. Thereafter, when the image forming area on the intermediate transfer body 12 moves to a position facing the second ink head 26B, second ink droplets are ejected from the respective nozzles 51 of the second ink head 26B. The second ink droplets are respectively disposed between the adjacent first ink droplets spaced apart on the intermediate transfer body 12. Subsequently, when the image forming area on the intermediate transfer body 12 moves to a position facing the second processing liquid head 28B, the same ink ejection position as the second ink droplet disposed on the intermediate transfer body 12 is reached. On the other hand, second processing droplets are ejected from the respective nozzles 51 of the second processing liquid head 28B. Similarly to the above, the plurality of second ink droplets arranged on the intermediate transfer body 12 are mixed and reacted with the second processing droplets ejected at the same position, so that the color material aggregates (dots) become the intermediate transfer body 12. Formed on top. Thus, a dot row 54 in the main scanning direction is formed on the intermediate transfer body 12.

  According to such a droplet ejection method, ink droplets (first and second ink droplets) ejected at positions adjacent to each other in the main scanning direction on the intermediate transfer body 12 are one ink droplet ( After the first ink droplet) is agglomerated by the mixing reaction with the treatment droplet, the other ink droplet (second ink droplet) is ejected. Without landing, landing interference is prevented. Further, since the treatment droplet is ejected to the same position as each ink droplet, each ink droplet spreads to a predetermined size without moving the coloring material, and a desired spreading rate is ensured. be able to. As a result, a high-quality image is formed on the intermediate transfer body 12.

  In the practice of the present invention, the arrangement order of the ink heads 26 and the treatment liquid heads 28 corresponding thereto is not limited to the example shown in FIG. 3, and the ink heads are adjacent to the upstream side in the intermediate transfer member conveyance direction. 26 may be provided to eject droplets in the order of treatment droplets and ink droplets to a predetermined droplet ejection position on the intermediate transfer body 12.

  However, as in the present embodiment, a mode in which ink droplets are ejected in the order of ink droplets and processed droplets at a predetermined droplet ejection position on the intermediate transfer body 12 is preferable. By controlling the wettability, ink droplets spread on the intermediate transfer body 12 to a predetermined size, and a desired spreading rate can be ensured. For example, the dot diameter can be easily controlled by controlling the wettability of the surface layer of the intermediate transfer body 12.

  The droplet ejection method according to the present embodiment is not limited to the case where a solid image is formed on the intermediate transfer body 12, but includes an image in which dots adjacent to each other in the main scanning direction (intermediate transfer body transport direction) have overlapping portions. In this case, high-quality image formation without landing interference is possible.

  In FIG. 1, the liquid storage / loading unit 34 is a liquid (color ink or treatment) supplied to each head 26, 28 (see FIG. 2) disposed in each droplet ejection unit 24 (24 </ b> C, 24 </ b> M, 24 </ b> Y, 24 </ b> K). Liquid tanks (not shown in FIG. 1, not shown in FIG. 4 and indicated by reference numeral 60), and each tank communicates with a corresponding head through a required flow path. A corresponding liquid (ink or treatment liquid) is supplied to each head. Further, the liquid storage / loading unit 34 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.

  Further, the ink jet recording apparatus 10 of the present example includes a solvent removing unit 18 that absorbs and removes liquid components (ink and solvent of the processing liquid) separated by agglomeration of ink droplets attached on the intermediate transfer body 12. A preheating unit 36 for preheating the intermediate transfer body 12, a pair of recording medium conveyance rollers 40A and 40B for supporting and conveying the recording medium 14 supplied from the paper feeding unit 38, and a recording medium conveyance roller The intermediate transfer body in a state where the transfer section 20 for transferring the primary image formed on the intermediate transfer body 12 to the recording medium 14 conveyed by the nip 40A and 40B, and the intermediate transfer body 12 and the recording medium 14 are bonded together. 12 and the cooling part 42 for cooling the recording medium 14, the peeling part 44 for peeling the recording medium 14 from the intermediate transfer body 12, and the residual ink adhering to the image forming surface 12A of the intermediate transfer body 12 after transfer. And a cleaning unit 46 for removing the solvent and the like. Further, a fixing unit 48 for fixing the image transferred to the recording medium 14 is provided on the downstream side of the peeling unit 44 in the recording medium conveyance direction (the direction indicated by arrow B in FIG. 1).

  The solvent removal unit 18 is disposed on the downstream side of the printing unit 16 in the intermediate transfer body conveyance direction, and includes a solvent removal roller 18A provided at a position facing the roller 22B with the intermediate transfer body 12 interposed therebetween. The solvent removal roller 18A is composed of a roller-like porous body, and is disposed so as to contact the image forming surface 12A of the intermediate transfer body 12. An ink aggregate is formed by the action of the processing liquid, and the ink separated from the ink aggregate and the liquid solvent (residual solvent) of the processing liquid are removed from the intermediate transfer body 12 by the solvent removal roller 18A.

  The surface energy of the surface of the solvent removal roller 18A (the surface in contact with the image forming surface 12A of the intermediate transfer body 12) is preferably smaller than the surface energy of the image forming surface 12A of the intermediate transfer body 12, and in this example, the solvent removal A member having a surface energy of 30 mN / m or less is applied to the roller 18A.

  By removing the solvent using the solvent removal roller 18A that satisfies the above-mentioned surface energy condition, it is possible to prevent the ink aggregates from adhering to the solvent removal roller 18A and to remove only the solvent on the intermediate transfer body 12. Become.

  Instead of the solvent removal roller 18A, a method of removing excess solvent from the intermediate transfer member 12 with an air knife, a method of heating the intermediate transfer member 12 to evaporate the solvent, or the like may be applied. The solvent removal method may be any of the methods exemplified above, but it is more preferable to use a method that does not rely on heating.

  In the method of heating the surface of the intermediate transfer body 12 or the method of evaporating the solvent by applying heat to the ink aggregate on the intermediate transfer body 12, the solvent is excessively removed by overheating of the ink aggregate, and the transfer is performed. In some cases, the preferred viscoelasticity of the aggregate cannot be maintained, and the transferability to the recording medium 14 may be deteriorated. Furthermore, there is a concern that heat generated by overheating affects the ejection performance of the heads 26 and 28.

  On the other hand, in the aspect in which the solvent on the image forming surface 12A of the intermediate transfer body 12 is removed by the solvent removing roller 18A, even when a large amount of processing liquid is applied to the image forming surface 12A of the intermediate transfer body 12, the intermediate transfer body. Since the solvent on 12 is suitably removed, a large amount of solvent (dispersion medium) is not transferred to the recording medium 14 at the transfer unit 20. Therefore, even when paper is used as the recording medium 14, problems characteristic to aqueous solvents such as curls and cockles do not occur.

  Further, by removing the excess solvent from the ink aggregate using the solvent removing unit 18, the ink aggregate can be concentrated and the internal aggregating force can be further increased. Thereby, the fusion of the resin particles contained in the ink aggregate is effectively promoted, and a stronger internal cohesive force can be applied to the ink aggregate up to the transfer step by the transfer unit 20. Further, the effective concentration of the ink aggregates by removing the solvent can impart good fixability and gloss to the image even after the image is transferred to the recording medium 14.

  Note that it is not always necessary to remove all the solvent on the intermediate transfer body 12 by the solvent removing unit 18. If the ink aggregate is excessively removed by excessively removing the ink aggregate, the adhesion of the ink aggregate to the transfer body becomes too strong, and an excessive pressure is required for the transfer. Rather, in order to maintain viscoelasticity suitable for transferability, it is preferable to leave a small amount.

  The effects obtained by leaving a small amount of the solvent on the intermediate transfer member 12 include the following. That is, since ink aggregates are hydrophobic and solvent components that are difficult to volatilize (mainly organic solvents such as glycerin) are hydrophilic, ink aggregates and residual solvent components are separated after solvent removal, and residual solvent components A thin liquid layer is formed between the ink aggregate and the intermediate transfer body 12. Therefore, the adhesive force of the ink aggregate to the intermediate transfer body 12 becomes weak, which is advantageous for improving transferability.

  The preheating unit 36 is disposed downstream of the solvent removal unit 18 in the conveyance direction of the intermediate transfer body, and is provided on the back surface 12B side of the image forming surface 12A of the intermediate transfer body 12 (not shown in FIG. 1, not shown in FIG. 5). The intermediate transfer body 12 on which the primary image is formed is preliminarily heated from the back surface 12B side by a heater.

  The heating temperature range of the heater disposed in the preheating unit 36 is 40 ° C. to 100 ° C., and is set lower than the heating temperature at the time of transfer. By preheating the image forming area of the intermediate transfer body 12, it is possible to set the heating temperature of the transfer unit 20 lower than when no preheating is performed, and further, the transfer time of the transfer unit 20 is reduced. be able to.

  The configuration of the paper supply unit 38 that supplies the recording medium 14 to the transfer unit 20 is an aspect in which a magazine for rolled paper (continuous paper) is provided, or a cut paper instead of or in combination with a magazine for rolled paper. There is a mode in which paper is supplied by a cassette loaded with stacks. 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 14 applied to this example include permeable media such as plain paper and inkjet exclusive paper, non-permeable or low permeable media such as coated paper, and adhesive and release labels on the back surface. There are various media such as sticker paper, resin films such as OHP sheets, metal sheets, cloth, and wood.

  The transfer unit 20 is disposed downstream of the preheating unit 36 in the intermediate transfer member conveyance direction, and includes a transfer heating roller having heaters (not shown in FIG. 1 and representative of a plurality of heaters shown in FIG. 5 by reference numeral 89). 20A and a heating facing roller 20B for a heating and pressing nip disposed opposite thereto, and the intermediate transfer body 12 and the recording medium 14 are sandwiched between these rollers 20A and 20B, and a predetermined temperature is set. (When a polymer such as a dispersant or latex in the ink is contained, a temperature equal to or higher than the softening point of the polymer is preferable.) While heating to a predetermined pressure (nip pressure), the intermediate transfer member 12 is heated. The primary image formed above is transferred to the recording medium 14.

  The heating temperature during transfer by the transfer unit 20 is preferably 80 ° C to 170 ° C, and more preferably 100 ° C to 150 ° C from the viewpoint of transferability. When the heating temperature at the time of transfer by the transfer unit 20 is 170 ° C. or higher, there is a problem such as deformation of the intermediate transfer body 12, while when it is 80 ° C. or lower, there is a problem that transferability is deteriorated.

  Examples of the means for adjusting the nip pressure at the time of transfer in the transfer unit 20 include a mechanism (drive means) that moves the transfer heating roller 20A in the vertical direction (shown by C) in FIG.

  The cooling unit 42 is disposed on the downstream side of the transfer unit 20 in the conveyance direction of the intermediate transfer member, and cools the transfer unit 20 in a state where the intermediate transfer member 12 and the recording medium 14 are bonded to each other. The cooling unit 42 is preferably applied with a mode in which cool air is blown by a cooling fan or the like, and the cooling temperature or the like can be adjusted. The cooling unit 42 shown in this example has a configuration in which a moving time (cooling time) of the intermediate transfer body 12 for cooling to a desired temperature is secured. By peeling the intermediate transfer body 12 and the recording medium 14 after cooling, transfer failure due to temperature unevenness or the like can be prevented, and stable image transfer (peeling) becomes possible.

  The peeling unit 44 is disposed on the downstream side of the cooling unit 42 in the conveyance direction of the intermediate transfer body, and the intermediate transfer body 12 has the rigidity (waist strength) of the recording medium 14 by the winding curvature of the peeling roller 22E of the intermediate transfer body 12. The recording medium 14 is peeled off. The peeling portion 44 may be used in combination with means for promoting peeling such as a peeling nail.

  The fixing unit 48 is disposed downstream of the peeling unit 44 in the recording medium conveyance direction (the direction indicated by the arrow B in FIG. 1), and includes a heating roller pair 48A capable of adjusting the temperature in the range of 100 ° C. to 180 ° C. Is done. In the fixing unit 48, the polymer fine particles are formed (a thin film in which the polymer fine particles are dissolved is formed on the outermost surface of the image), thereby improving the fixability and scratch resistance. If the transfer unit 20 can achieve both transferability and film formation, a mode in which the fixing unit 48 is omitted is also possible.

  The cleaning unit 46 is arranged downstream of the peeling unit 44 in the conveyance direction of the intermediate transfer body, and serves as a means for cleaning the intermediate transfer body 12 after the image transfer to the recording medium 14 is completed on the image forming surface 12A of the intermediate transfer body 12. The blade includes a blade (not shown) that wipes and removes the remaining ink aggregate while abutting, and a collection unit (not shown) that collects the removed residual ink aggregate.

  The configuration of the cleaning means for removing the residual ink from the intermediate transfer body 12 is not limited to the above example, but a method of niping a brush roll, a water absorption roll, etc., an air blow method of blowing clean air, an adhesive roll method, There are combinations of these. 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.

  According to the inkjet recording apparatus 10 of the present embodiment, ink droplets that are ejected at positions adjacent to each other in the main scanning direction on the intermediate transfer body 12 in each droplet ejection unit 24 that constitutes the printing unit 16 (first And the second ink droplet), one ink droplet (first ink droplet) aggregates due to the mixing reaction with the processing droplet, and then the other ink droplet (second ink droplet) is ejected. Therefore, even if these ink droplets come into contact with each other, landing interference is prevented without being united. Further, since the treatment droplet is ejected to the same position as each ink droplet, each ink droplet spreads to a predetermined size without moving the coloring material, and a desired spreading rate is ensured. Thus, an image made of ink aggregates (color material aggregates) can be formed on the intermediate transfer body 12 with high quality. Then, after the solvent component of the ink and the processing liquid is removed from the intermediate transfer body 12 by the solvent removal unit 18, the image formed on the intermediate transfer body 12 is transferred to the recording medium 14 by the transfer unit 20. Is done.

[Configuration of supply system]
FIG. 4 is a schematic diagram showing the configuration of the ink supply system in the inkjet recording apparatus 10. 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 ink head 26 and is included in the liquid storage / loading unit 34 described with reference to FIG. 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. 4, a filter 62 is provided between the ink supply tank 60 and the ink head 26 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. 4, a configuration in which a sub tank is provided in the vicinity of the ink head 26 or integrally with the ink head 26 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 10 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 discharge surface of the ink head 26. ing.

  The maintenance unit including the cap 64 and the cleaning blade 66 can be moved relative to the ink head 26 by a moving mechanism (not shown), and is moved from a predetermined retracted position to a maintenance position below the ink head 26 as necessary. The

  The cap 64 is displaced up and down relatively with respect to the ink head 26 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 ink head 26, thereby covering the ink ejection surface (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 operates.

  Before such a state is reached (within the range of viscosity that can be ejected by the operation of the piezoelectric element), the piezoelectric element is operated, and the cap 64 (ink near the nozzle whose viscosity has increased) is discharged. Preliminary ejection (purging, idle ejection, collar ejection, dummy ejection) is performed toward the ink receiver.

  A mode in which preliminary ejection is performed by ejecting ink toward the intermediate transfer member 12 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 the same images are formed, the frequency of ink ejection at a specific nozzle is reduced, and the possibility of occurrence of ejection abnormality is increased, so that preliminary ejection can be performed between images for the specific nozzle. preferable.

  When preliminary ejection is performed on the intermediate transfer body 12, the solvent removal roller 18A and the transfer heating roller 20A are moved so that the ink from the preliminary ejection does not adhere to the solvent removal roller 18A and the transfer heating roller 20A, and the solvent removal roller is moved. A predetermined clearance (for example, about 10 mm) may be provided between 18A and the transfer heating roller 20A and the intermediate transfer body 12.

  Further, when air bubbles are mixed in the ink in the ink head 26 (in the pressure chamber), the ink cannot be ejected from the nozzle even if the piezoelectric element is operated. In such a case, the cap 64 is applied to the ink head 26, the ink in the pressure chamber (ink mixed with bubbles) is removed by suction with the suction pump 67, and the suctioned and removed ink is sent to the collection 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. In addition, since the suction operation is performed on the entire ink in the pressure chamber, the 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 ink head 26 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.

[Explanation of control system]
FIG. 5 is a principal block diagram showing the system configuration of the inkjet recording apparatus 10. The inkjet recording apparatus 10 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, an ink head driver 84, a processing liquid head driver 85, 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 inkjet recording apparatus 10 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 10 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. 5, the motor (actuator) arranged in each part in the apparatus is represented by reference numeral 88. For example, the motor 88 shown in FIG. 5 includes a motor for driving the driving roller among the rollers 22A to 22G in FIG. 1, a motor for the moving mechanism of the solvent removing roller 18A, a motor for the moving mechanism of the transfer heating roller 20A, and the like. include.

  The heater driver 78 is a driver that drives the heater 89 in accordance with an instruction from the system controller 72. In FIG. 5, a plurality of heaters provided in the inkjet recording apparatus 10 are represented by reference numeral 89. For example, the heater 89 illustrated in FIG. 5 includes the heater of the preheating unit 36 illustrated in FIG. 1, the heater included in the heating roller pair 48 </ b> A of the fixing unit 48, and the like.

  The transfer control unit 79 performs pressure control and temperature control of the transfer heating roller 20A of the transfer unit 20. For each type of recording medium 14 and each type of ink, the optimal pressing value and the optimal temperature value of the transfer heating roller 20A 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 20A 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 ink head driver 84 and the treatment liquid head driver 85. The required signal processing is performed in the print control unit 80, and the ejection amount and ejection timing of the ink droplets of the ink head 26 (26A, 26B) are controlled via the ink head driver 84 based on the image data. At the same time, the treatment liquid ejection amount and ejection timing of the treatment liquid head 28 (28A, 28B) are controlled via the treatment liquid head driver 85. 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 ink head driver 84 generates a drive signal to be applied to the piezoelectric element of each ink head 26 (26A, 26B) based on the image data given from the print control unit 80, and applies the drive signal to the piezoelectric element. And including a drive circuit for driving the piezoelectric element. Note that the ink head driver 84 shown in FIG. 5 may include a feedback control system for keeping the driving conditions of the ink head 26 constant.

  Similarly to the ink head driver 84 described above, the processing liquid head driver 85 is a drive signal applied to the piezoelectric elements of the processing liquid heads 28 (28A, 28B) based on the image data given from the print controller 80. And a drive circuit for driving the piezoelectric element by applying the drive signal to the piezoelectric element. Note that the processing liquid head driver 85 shown in FIG. 5 may include a feedback control system for keeping the driving conditions of the processing liquid head 28 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 for the processing liquid in the print control unit 80. In other words, the print control unit 80 performs processing for converting the input RGB image data into dot data of four colors of CMYK and dot data of the processing liquid. 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 12 must be a mirror image of the secondary image finally formed on the recording medium 14 in consideration of inversion at the time of transfer. That is, the drive signals supplied to the ink heads 26 (26A, 26B) and the processing liquid heads 28 (28A, 28B) are drive signals corresponding to the specular image, and the print control unit 80 inverts the input image. It is necessary to apply.

  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 290 may use a semiconductor memory such as a ROM or 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.

[Description of ink]
<Ink>
The ink according to the present invention contains at least a pigment, a polymer component, and a solvent. As a means for incorporating the polymer component in the ink, there are a method of dispersing in the ink as polymer fine particles, a method of using a capsule pigment in which the pigment surface is covered with the polymer component, a method of attaching the polymer component around the pigment, Various methods such as a combination of these methods can be employed.

  The pigment used in the ink of the present invention is particularly preferably a pigment dispersed with a dispersant, a self-dispersing pigment, a pigment whose surface is coated with a resin (microcapsule pigment), and a polymer graft pigment. From the viewpoint of pigment aggregation, a form modified with a carboxyl group having a low dissociation degree is more preferable.

  The resin of the microcapsule pigment is not limited, but is preferably a high molecular compound having a self-dispersibility or solubility in water and an anionic group (acidic). This resin usually has a number average molecular weight of about 1,000 to 100,000, and particularly preferably about 3,000 to 50,000. Further, it is preferable that this resin is dissolved in an organic solvent to form a solution. When the number average molecular weight of the resin is within this range, the function as a coating film in the pigment or as a coating film in the ink composition can be sufficiently exhibited.

  The resin may be self-dispersible or soluble, or may have a function added by some means. For example, it may be a resin in which an anionic group such as a carboxyl group, a sulfonic acid group, or a phosphonic acid group is introduced by neutralization with an organic amine or an alkali metal. Further, it may be a resin into which one or two or more anionic groups of the same type or different types are introduced. In the present invention, a resin in which a carboxyl group is introduced by neutralization with a base is preferably used.

  Although it does not specifically limit as a pigment used for this invention, As a specific example, as a pigment for orange or yellow, C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185. Examples of red or magenta pigments include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the pigment for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  Examples of black pigments include C.I. I. Pigment black 1, C.I. I. Pigment black 6, C.I. I. Pigment black 7 and the like.

  The concentration of the color material contained in the ink used in the present invention may be selected to an optimum value depending on the color material used, but it should be in the range of 0.1% by weight to 40% by weight with respect to the total weight of the ink. Is preferred. More preferably, they are 1 weight%-30 mass%, More preferably, they are 2 weight%-20 mass%.

  As a means for containing the polymer component in the ink according to the present invention, a method of containing polymer fine particles in the ink is preferably used. The polymer fine particles can enhance the thickening action and aggregation action of the ink by reaction with the treatment liquid, and can improve the image quality. In particular, a highly safe ink can be obtained by incorporating anionic polymer fine particles into the ink.

  By using polymer fine particles that react with the treatment liquid and cause thickening / aggregation action in the ink, the quality of the image can be improved. At the same time, depending on the type of polymer fine particles, the polymer fine particles may be coated on the intermediate transfer member. And has the effect of improving the abrasion resistance and water resistance of the image.

  The dispersion method in the polymer ink is not limited to emulsion, and it may be dissolved or exist in a colloidal dispersion state.

  The polymer fine particles may be obtained by dispersing the polymer fine particles using an emulsifier, or may be dispersed without using an emulsifier. As the emulsifier, a low molecular weight surfactant is usually used, but a high molecular weight surfactant can also be used as an emulsifier. It is also preferable to use capsule type polymer fine particles (core / shell type polymer fine particles having different compositions at the center and outer edge of the particle) whose outer shell is made of acrylic acid, methacrylic acid or the like.

  As a dispersion method, polymer fine particles not using a low molecular weight surfactant are called soap-free latex, including polymer fine particles using a high molecular weight surfactant and polymer fine particles not using an emulsifier. For example, a polymer having a water-soluble group such as a sulfonic acid group or a carboxylic acid group described above (a polymer in which a solubilizing group is graft-bonded, a monomer having a solubilizing group, and an insoluble portion) Polymer fine particles using a block polymer obtained from a monomer as an emulsifier are also included.

  The acid polymer used in the present invention is preferably a carboxylic acid acid polymer.

  Since the pKa of the carboxylic acid is approximately 3 to 4, the acid polymer is almost dissociated at pH 5, so that it has dispersion stability and does not cause aggregation due to electric repulsion. If it is less than this, it will be in a non-dissociated state, the electric repulsion will be lost, and aggregation will occur.

  In the present invention, it is particularly preferable to use this soap-free latex. The soap-free latex, compared with polymer fine particles polymerized using a conventional emulsifier, inhibits the reaction aggregation and film formation of the polymer fine particles, or the free emulsifier. However, it moves to the surface after the film formation of the polymer fine particles, and there is no concern that the adhesiveness between the aggregate in which the pigment and the polymer fine particles are mixed and the intermediate transfer member is lowered.

  Examples of the resin component added to the ink as polymer fine particles include acrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, butadiene resins, styrene resins, and the like.

  From the viewpoint of imparting high-speed cohesiveness to the polymer fine particles, those having a carboxylic acid group having a low dissociation degree are more preferable. Since the carboxylic acid group is easily affected by pH change, the dispersion state is easily changed and the cohesiveness is high.

  The change of the dispersion state with respect to the pH change of the polymer fine particles can be adjusted by the content ratio of the constituent component in the polymer fine particles having a carboxylic acid group such as an acrylate ester, and the like depending on the anionic surfactant used as the dispersant. Can also be adjusted.

  The resin component of the polymer fine particles is preferably a polymer having both a hydrophilic portion and a hydrophobic portion. By having the hydrophobic portion, the hydrophobic portion is oriented inside the polymer fine particle, the hydrophilic portion is efficiently oriented outside, and the effect of increasing the dispersion state with respect to the pH change of the liquid is greater, and aggregation is caused. It is done more efficiently.

  Examples of commercially available polymer fine particles include Jonkrill 537, 7640 (styrene-acrylic resin emulsion, manufactured by Johnson Polymer Co., Ltd.), Microgel E-1002, E-5002 (styrene-acrylic resin emulsion, Nippon Paint Co., Ltd.). Manufactured), Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin) Emulsion, manufactured by Nippon Zeon Co., Ltd., Jurimer ET-410, FC-30 (acrylic resin emulsion, manufactured by Nippon Pure Chemicals Co., Ltd.), Aron HD-5, A-104 (acrylic resin emulsion, manufactured by Toagosei Co., Ltd.) ), Cybino Le SK-200 (acrylic resin emulsion, manufactured by Saiden Chemical Industry Co., Ltd.), Zaikthene L (acrylic resin emulsion, manufactured by Sumitomo Seika Chemicals Co., Ltd.) and the like, not limited to this.

  The molecular weight of the polymer fine particles added to the ink is preferably 5,000 or more in view of the adhesive strength when fused. If it is less than 5,000, the effect of improving the internal cohesive force of the ink aggregate when aggregated, fixing the image on the recording medium, and the effect of improving the image quality are insufficient.

  The volume average particle diameter of the polymer fine particles is preferably in the range of 10 nm to 1 μm, more preferably in the range of 10 to 500 nm, still more preferably in the range of 20 to 200 nm, and particularly preferably in the range of 50 to 200 nm. If the thickness is 10 nm or less, the effect of improving the image quality and the improvement of transferability cannot be expected even if they are aggregated. When the thickness is 1 μm or more, there is a concern that the ejection properties of the ink from the head and the storage stability may deteriorate. Moreover, there is no restriction | limiting in particular regarding the volume average particle diameter distribution of a polymer particle, What has a wide volume average particle diameter distribution or a thing with a monodispersed volume average particle diameter distribution may be sufficient.

  Further, two or more kinds of polymer fine particles may be mixed and used in the ink.

  As the pH adjuster added to the ink of the present invention, an organic base or an inorganic alkali base can be used as a neutralizing agent. The pH adjusting agent is preferably added so that the inkjet ink has a pH of 6 to 10 for the purpose of improving the storage stability of the inkjet ink.

  The ink of the present invention preferably contains a water-soluble organic solvent for the purpose of preventing clogging of the nozzles of the inkjet head due to drying. Such water-soluble organic solvents include wetting agents and penetrants.

  Examples of the water-soluble organic solvent include polyhydric alcohols, polyhydric alcohol derivatives, nitrogen-containing solvents, alcohols, sulfur-containing solvents and the like, as in the case of the treatment liquid. Specific examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, and glycerin. Examples of polyhydric alcohol derivatives include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and diglycerin. Examples include ethylene oxide adducts. Examples of nitrogen-containing solvents include pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, and triethanolamine. Examples of alcohols include alcohols such as ethanol, isopropyl alcohol, butyl alcohol, and benzyl alcohol. Thiodiethanol, thiodiglycerol, sulfolane, dimethyl sulfoxide and the like. In addition, propylene carbonate, ethylene carbonate, or the like can be used.

  The ink of the present invention can contain a surfactant.

  Examples of surfactants include fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate ester salts, naphthalene sulfonate formalin condensates, Anionic surfactants such as oxyethylene alkyl sulfate esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines Nonionic surfactants such as glycerin fatty acid ester and oxyethyleneoxypropylene block copolymer are preferred. Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred.

  Further, pages (37) to (38) of JP-A-59-157636, Research Disclosure No. The surfactants described in 308119 (1989) can also be used. In addition, fluorine (fluorinated alkyl) and silicone surfactants as described in JP-A Nos. 2003-322926, 2004-325707, and 2004-309806 are also used. Can do. These surface tension modifiers can also be used as antifoaming agents, and fluorine-based, silicone-based compounds, chelating agents represented by EDTA, and the like can also be used.

  The surface tension is lowered to increase the wettability on the intermediate transfer member or on the treatment liquid, and the cohesive action is effectively promoted by increasing the contact area between the two liquids.

  The surface tension of the ink of the present invention is preferably from 10 to 50 mN / m. When direct recording is performed, the penetrability to the permeable recording medium, and when recording is performed by the intermediate transfer method, the intermediate transfer member is used. From the viewpoint of achieving both the wettability above, the formation of fine droplets and the discharge properties, it is more preferably 15 to 45 mN / m.

  The viscosity of the ink of the present invention is preferably 1.0 to 20.0 cP.

  In addition, a pH buffer, an antioxidant, a fungicide, a viscosity modifier, a conductive agent, an ultraviolet absorber, and the like can be added as necessary.

<Processing liquid>
The treatment liquid according to the present invention is preferably a treatment liquid that aggregates pigments and polymer fine particles contained in the ink by changing the pH of the ink, thereby generating an aggregate.

  Treatment liquid components include polyacrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, tartaric acid, lactic acid, sulfonic acid, orthophosphoric acid, pyrrolidone It is preferably selected from carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, derivatives of these compounds, or salts thereof.

  A preferable example of the treatment liquid according to the present invention is a treatment liquid to which a polyvalent metal salt or polyallylamine is added. These compounds may be used alone or in combination of two or more.

  The treatment liquid according to the present invention preferably has a pH of 1 to 6, more preferably 2 to 5, and particularly preferably 3 to 5 from the viewpoint of pH aggregation performance with the ink. .

  In the treatment liquid according to the present invention, the addition amount of the component for aggregating the pigment and polymer fine particles of the ink is preferably 0.01% by weight or more and 20% by weight or less with respect to the total weight of the liquid. When the amount is 0.01% by weight or less, concentration dispersion does not proceed sufficiently when the treatment liquid and the ink are in contact with each other, and agglomeration due to pH change may not occur sufficiently. On the other hand, if it is 20% by weight or more, the dischargeability from the ink jet head may deteriorate.

  The treatment liquid according to the present invention preferably contains water and other additive-soluble organic solvents for the purpose of preventing clogging of the nozzles of the inkjet head due to drying. Such water and other additive-soluble organic solvents include wetting agents and penetrants.

  These solvents can be used alone or in combination with water and other additives.

  The content of water and other additive-soluble organic solvents is preferably 60% by weight or less based on the total weight of the treatment liquid. When the amount is more than 60% by weight or more, the viscosity of the treatment liquid increases, and the dischargeability from the inkjet head may deteriorate.

  The treatment liquid may further contain a resin component in order to improve fixability and abrasion resistance. The resin component may be any resin component that does not impair the ejection properties from the head when the treatment liquid is ejected by the ink jet method and has storage stability, and water-soluble resins and resin emulsions can be used freely.

  The coagulability may be further enhanced by adding polymer fine particles having a polarity opposite to that of the ink to the treatment liquid and aggregating with the pigment and polymer fine particles in the ink.

  In addition, a curing agent corresponding to the polymer fine particle component contained in the ink is contained in the treatment liquid, and after the two liquids contact, the resin emulsion in the ink component aggregates and crosslinks or polymerizes to increase the cohesiveness. Also good.

  The treatment liquid according to the present invention can contain a surfactant.

  Examples of surfactants include fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate ester salts, naphthalene sulfonate formalin condensates, Anionic surfactants such as oxyethylene alkyl sulfate esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines Nonionic surfactants such as glycerin fatty acid ester and oxyethyleneoxypropylene block copolymer are preferred. Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred.

  Further, pages (37) to (38) of JP-A-59-157636, Research Disclosure No. The surfactants described in 308119 (1989) can also be used. In addition, fluorine (fluorinated alkyl) and silicone surfactants as described in JP-A Nos. 2003-322926, 2004-325707, and 2004-309806 are also used. Can do. These surface tension modifiers can also be used as antifoaming agents, and fluorine-based, silicone-based compounds, chelating agents represented by EDTA, and the like can also be used.

  This is effective in reducing the surface tension and increasing the wettability on the intermediate transfer member. Further, even when ink is ejected in advance, the wettability on the ink is enhanced, and the cohesive action is effectively promoted by increasing the contact area of the two liquids.

  The surface tension of the treatment liquid according to the present invention is preferably 10 to 50 mN / m. When direct recording is performed, the penetrability into the permeable recording medium, or when recording is performed by an intermediate transfer method, From the viewpoint of achieving both wettability on the intermediate transfer member, fine droplet formation and ejection properties, it is more preferably 15 to 45 mN / m.

  The viscosity of the treatment liquid according to the present invention is preferably 1.0 to 20.0 cP.

  In addition, pH buffering agents, antioxidants, fungicides, viscosity modifiers, conductive agents, ultraviolet rays, absorbents, and the like can be added as necessary.

〔Example〕
Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

<Preparation of pigment ink C>
(Preparation of pigment dispersion)
A dispersion was prepared by stirring and mixing 10 g of Cyanine Blue A-22 (PB15: 3) manufactured by Dainichi Seika Co., Ltd., low molecular weight dispersant 2-1, 10.0 g, 4.0 g of glycerin, and 26 g of ion-exchanged water. Next, using the ultrasonic irradiation device (SONICS Vibra-cell VC-750, taper microchip: φ5 mm, Amplitude: 30%), the above dispersion is intermittently irradiated with ultrasonic waves (irradiation 0.5 seconds, The pigment was further dispersed by irradiation for 2 hours at a rest of 1.0 second to obtain a 20% by mass pigment dispersion. The low molecular weight dispersant 2-1 is represented by the following chemical formula.

  Separately from the above, the compound shown below was weighed, stirred and mixed to prepare a mixed solution I.

Glycerin 5.0g
Diethylene glycol 10.0g
Olfin E1010 (Nissin Chemical Industry) 1.0g
Ion exchange water 11.0g
This mixed liquid I was slowly dropped into 23.0 g of a stirred 44% SBR dispersion (polymer fine particles: 3% by mass of acrylic acid, Tg (glass transition temperature) 30 ° C.), and stirred and mixed. Prepared.

  Further, 100 g of cyan pigment ink C (cyan ink) was prepared by stirring and mixing the mixed liquid II while slowly dropping into the 20% by mass pigment dispersion described above. Using the pH meter WM-50EG manufactured by Toa DKK Co., Ltd., the pH of the pigment ink C prepared in this way was measured, and the pH value was 8.5.

<Preparation of pigment ink M>
Cromophtal Jet Magenta DMQ (PR-122) manufactured by Ciba Specialty Chemicals was used instead of the pigment used in the preparation of Pigment Ink C. Except for the pigment, a magenta pigment ink M (magenta ink) was prepared in the same manner as the preparation of the pigment ink C described above. When the pH of the pigment ink M thus prepared was measured with a pH meter WM-50EG manufactured by Toa DKK, the pH value was 8.5.

<Preparation of pigment ink Y>
Instead of the pigment used for the preparation of the pigment ink C, Irgalite Yellow GS (PY74) manufactured by Ciba Specialty Chemicals was used. Except for the pigment, yellow pigment ink Y (yellow ink) was prepared in the same manner as in the preparation of pigment ink C described above. When the pH of the pigment ink Y thus prepared was measured with a pH meter WM-50EG manufactured by Toa DKK, the pH value was 8.5.

<Preparation of pigment ink K>
A black pigment was prepared in the same manner as in the preparation of the pigment ink C described above except that the pigment dispersion used for the preparation of the pigment ink C was a dispersion CAB-O-JET ^™ _200 (carbon black) manufactured by CABOT. Ink K (black ink) was prepared. When the pH of the pigment ink K thus prepared was measured with a pH meter WM-50EG manufactured by Toa DKK Co., Ltd., the pH value was 8.5.

<Preparation of treatment liquid>
The treatment liquid was prepared by mixing the following materials.
・ Diethylene glycol 20g
・ Orphine E1010 (manufactured by Nissin Chemical Industry) 1g
・ 2-Pyrrolidone-5-carboxylic acid 1g
・ Sodium hydroxide 0.25g
・ Ion exchange water 77.8g
When the pH of the second treatment solution thus prepared was measured with a pH meter WM-50EG manufactured by Toa DKK Co., Ltd., the pH value was 3.5.

  When an image was recorded by the ink jet recording apparatus 10 described above using the ink and the treatment liquid thus produced, a preferable recorded image without image quality deterioration was obtained.

  In the case of using a single-pass droplet ejection device that is not a configuration of the present invention and that ejects adjacent droplets of ink liquid before supplying the treatment liquid, image quality deterioration due to droplet ejection interference is observed. On the other hand, when the ink jet recording apparatus of the present invention was used, a preferable recorded image without image quality deterioration due to droplet ejection interference was obtained.

(Second Embodiment)
Next, a second embodiment 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. 6 is a configuration diagram showing an example of a nozzle arrangement structure of each head 26 and 28 arranged in the droplet ejection unit 24 ′ as the second embodiment. In FIG. 6, the same reference numerals are given to portions common to FIG. 3. As shown in FIG. 6, the droplet ejection unit 24 ′ of this example is provided with first to fourth ink heads 26 (26 </ b> A to 26 </ b> D), and the first to fourth ink heads 26 corresponding to the respective ink heads 26. The treatment liquid heads 28 (28A to 28D) are provided adjacent to the downstream side in the intermediate transfer member conveyance direction. That is, the first ink head 26A, the first processing liquid head 28A, the second ink head 26B, the second processing liquid head 28B, and the third ink head are sequentially arranged from the upstream side along the intermediate transfer body conveyance direction. 26C, a third treatment liquid head 28C, a fourth ink head 26D, and a fourth treatment liquid head 28D are disposed.

  As shown in FIG. 6, the same nozzle arrangement structure as that of the first and second ink heads 26A and 26B is applied to the third and fourth ink heads 26C and 26D, respectively. Similarly to the first embodiment, the first to fourth processing liquid heads 28A to 28D are respectively disposed adjacent to the upstream side in the intermediate transfer member conveyance direction, and the first to fourth ink heads 26A to 26D. The same nozzle arrangement structure is applied. That is, the droplet ejection unit 24 ′ of the second embodiment corresponds to a configuration in which the two droplet ejection units 24 of the first embodiment are arranged along the intermediate transfer body conveyance direction.

  FIG. 7 is an explanatory view showing the droplet ejection order of the heads 26 and 28 with respect to the intermediate transfer body 12. In FIG. 7, each circle shown on the intermediate transfer body 12 represents a droplet ejection position of each head 26, 28, and a number shown in each circle represents a head that ejects droplets relative to the droplet ejection position. Represents a number. When the number is “1”, the droplet ejection positions of the first ink head 26A and the first processing liquid head 28A, and when the number is “2”, the second ink head 26B and the second processing are performed. The droplet ejection position of the liquid head 28B, when the number is “3”, the droplet ejection position of the third ink head 26C and the third treatment liquid head 28C, and the number is “4”, the fourth The droplet ejection positions of the ink head 26D and the fourth treatment liquid head 28D are respectively shown.

  It should be noted that dots formed by ink droplets ejected at each droplet ejection position on the intermediate transfer body 12 are not only in the main scanning direction but also in the droplet ejection positions adjacent to the sub-scanning direction (intermediate transfer body transport direction). The dot formed by the ink droplet to be ejected is at least partially overlapped with the dot formed by the ink droplet ejected to the droplet ejection position indicated by the same head number. The nozzle pitch of each head 26 and 28, the discharge conditions (discharge droplet amount, discharge cycle, etc.), and the transport conditions (transport speed) of the intermediate transfer body 12 are determined.

  The droplet ejection method of this embodiment is performed in the following order. For example, when a solid image is formed on the entire image forming area on the intermediate transfer body 12, as shown in FIG. 7, each droplet ejection in the first row (leftmost) is carried along with the conveyance of the intermediate transfer body 12. Among the positions, the first ink droplet and the first processing droplet are sequentially ejected from the first ink head 26A and the first processing liquid head 28A to the droplet ejection position indicated by the numeral “1”. The Subsequently, the second ink liquid is supplied from the second ink head 26B and the second processing liquid head 28B to the remaining droplet ejection positions in the first row, that is, the droplet ejection positions indicated by the numeral “2”. Droplets and second treatment droplets are sequentially ejected. Next, the third ink droplets from the third ink head 26C and the third treatment liquid head 28C to the droplet ejection positions indicated by the numeral “3” among the droplet ejection positions in the second row. Then, the third treatment droplet is sequentially ejected. Subsequently, the fourth ink liquid is supplied from the fourth ink head 26D and the fourth treatment liquid head 28D to the remaining droplet ejection positions in the second row, that is, the droplet ejection positions indicated by the numeral “4”. Drops and fourth process droplets are sequentially ejected. For the third and subsequent rows, the same droplet ejection as in the first and second rows is repeated.

  According to the present embodiment, ink droplets that are ejected on the intermediate transfer body 12 not only in the main scanning direction but also in the sub-scanning direction (intermediate transfer body conveyance direction) (for example, the first ink droplets). And the third ink droplet), one of the ink droplets (first ink droplet) aggregates due to the mixing reaction with the processing droplet, and then the other ink droplet (third ink droplet) strikes. Therefore, even if the ink droplets come into contact with each other, the landing interference is prevented without being united. Further, since the treatment droplet is ejected to the same position as each ink droplet, each ink droplet spreads to a predetermined size without moving the coloring material, and a desired spreading rate is ensured. be able to. As a result, it is possible to form a higher quality image as compared with the first embodiment.

  Note that the droplet ejection method according to the present embodiment is not limited to the case where a solid image is formed on the intermediate transfer body 12, but includes an image in which dots adjacent in the sub-scanning direction (intermediate transfer body transport direction) overlap each other. In this case, high-quality image formation without landing interference is possible.

(Third embodiment)
Next, a third embodiment 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. 8 is a configuration diagram showing a main part of an ink jet recording apparatus 10 ′ as a third embodiment. In FIG. 8, parts that are the same as those in FIG.

  As shown in FIG. 8, the first and second ink heads 26A and 26B are provided in each droplet ejecting section 24 (24C, 24M, 24Y, 24K) constituting the printing section 16, and the intermediate transfer body transport direction. The first and second processing liquid heads 28A and 28B corresponding to the downstream side are provided adjacent to each other in the same manner as in the first embodiment (see FIG. 2). In this embodiment, a solvent removal roller 18A is provided adjacent to each processing liquid head 28A, 28B on the downstream side in the conveyance direction of the intermediate transfer member. A counter roller 18B is provided at a position facing each solvent removing roller 18A with the intermediate transfer body 12 interposed therebetween.

  According to this embodiment, even when a large amount of processing liquid is applied to the intermediate transfer body 12, the intermediate transfer is performed by the solvent removal roller 18A provided on the downstream side in the intermediate transfer body conveyance direction of each processing liquid head 28A, 28B. The solvent component on the body 12 can be reliably removed. As a result, the landing conditions of the ink droplets ejected from each ink head 26 on the upstream side and the downstream side in the conveyance direction of the intermediate transfer member can be made the same regardless of the amount of the processing liquid. The spread rate can be stabilized. As a result, a higher quality image can be formed.

  The image forming method and the image forming apparatus of the present invention have been described in detail above. However, the present invention is not limited to the above examples, and various improvements and modifications are made without departing from the gist of the present invention. Of course it is also good.

1 is a schematic configuration diagram of an ink jet recording apparatus according to a first embodiment. FIG. 1 is a plan view of a main part around a printing unit of the ink jet recording apparatus shown in FIG. It is the block diagram which showed an example of the nozzle arrangement structure of each head arrange | positioned at a droplet ejection part. Schematic diagram showing the configuration of the ink supply system of the ink jet recording apparatus shown in FIG. 1 is a principal block diagram showing the system configuration of the ink jet recording apparatus shown in FIG. It is the block diagram which showed an example of the nozzle arrangement structure of each head arrange | positioned at the droplet ejection part which concerns on 2nd Embodiment. Explanatory drawing showing the droplet ejection order of each head with respect to the intermediate transfer member Schematic configuration diagram of an ink jet recording apparatus according to a third embodiment Diagram explaining landing interference FIG. 2 is a diagram for explaining a two-component image forming method according to the prior art

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 12 ... Intermediate transfer body, 14 ... Recording medium, 16 ... Printing part, 18 ... Solvent removal part, 18A ... Solvent removal roller, 20 ... Transfer part, 24 ... Droplet ejection part, 26 ... Ink head, 28 ... Processing liquid head, 36 ... Preheating part, 42 ... Cooling part, 44 ... Peeling part, 46 ... Cleaning part, 48 ... Fixing part, 51 ... Nozzle

Claims (5)

While conveying the intermediate transfer body, the intermediate transfer body is provided with an ink containing a color material and a treatment liquid for aggregating the color material, and an image composed of the aggregate of the color material is applied to the intermediate transfer body. An image forming method for transferring an image formed on the intermediate transfer member to a recording medium,
The plurality of first ink droplets are arranged on the intermediate transfer member so as to be spaced apart from each other without contacting each other along a direction perpendicular to the conveyance direction of the intermediate transfer member. A first ink droplet ejecting step for ejecting the first ink droplet;
A first treatment liquid droplet ejecting step of ejecting first treatment droplets to the droplet ejection positions of the plurality of first ink droplets on the intermediate transfer member;
After the first ink droplet ejection step and the first treatment liquid droplet ejection step are performed, second ink droplets are disposed between the plurality of first ink droplets spaced on the intermediate transfer member. A second ink droplet ejecting step of ejecting the second ink droplet onto the intermediate transfer member;
After the first ink droplet ejection step and the first treatment liquid droplet ejection step are performed, the second treatment droplet is ejected to the droplet ejection position of the second ink droplet on the intermediate transfer member. A second treatment liquid spraying step;
A solvent removal step of removing the solvent component of the ink and the treatment liquid on the intermediate transfer member;
A transfer step of transferring an image from the intermediate transfer member to the recording medium;
An image forming method comprising: After the first ink droplet ejecting step and the first processing liquid droplet ejecting step are performed, the first ink droplets disposed on the intermediate transfer member are positioned adjacent to each other in the transport direction of the intermediate transfer member. A third ink droplet ejecting step of ejecting the third ink droplet against the intermediate transfer member so that the third ink droplet is disposed;
After the first ink droplet ejection step and the first treatment liquid droplet ejection step are performed, the third treatment droplet is ejected to the droplet ejection position of the third ink droplet on the intermediate transfer member. A third treatment liquid spraying step;
The image forming method according to claim 1, further comprising: After the second ink droplet ejecting step and the second processing liquid droplet ejecting step are performed, the second ink droplets disposed on the intermediate transfer body are positioned adjacent to the transport direction of the intermediate transfer body. A fourth ink droplet ejecting step of ejecting the fourth ink droplet against the intermediate transfer member so that the fourth ink droplet is disposed;
After the second ink droplet ejection step and the second processing liquid droplet ejection step are performed, the fourth treatment droplet is ejected onto the droplet ejection position of the fourth ink droplet on the intermediate transfer member. A fourth treatment liquid dropping step;
The image forming method according to claim 1, further comprising:   4. The image forming method according to claim 1, wherein the ink is a liquid containing an acid polymer that aggregates at a pH of less than 5, and the treatment liquid is a liquid of a pH of less than 5. 5. . While conveying the intermediate transfer body, the intermediate transfer body is provided with an ink containing a color material and a treatment liquid for aggregating the color material, and an image composed of the aggregate of the color material is applied to the intermediate transfer body. An image forming apparatus for transferring an image formed on the intermediate transfer member to a recording medium,
The plurality of first ink droplets are arranged on the intermediate transfer member so as to be spaced apart from each other without contacting each other along a direction perpendicular to the conveyance direction of the intermediate transfer member. First ink droplet ejection means for ejecting the first ink droplet;
First treatment liquid droplet ejecting means for ejecting first treatment droplets to the droplet ejection positions of the plurality of first ink droplets on the intermediate transfer member;
Between the plurality of first ink droplets provided on the downstream side in the transport direction of the intermediate transfer body from the first ink droplet ejection means and the first processing liquid droplet ejection means and spaced apart on the intermediate transfer body. Second ink droplet ejecting means for ejecting the second ink droplet against the intermediate transfer member so that the second ink droplet is disposed;
Provided on the downstream side in the transport direction of the intermediate transfer body from the first ink droplet ejection means and the first processing liquid droplet ejection means, and the second ink droplet ejection position on the intermediate transfer body is A second treatment liquid droplet ejecting means for ejecting two treatment droplets;
Solvent removing means for removing the solvent component of the ink and the treatment liquid on the intermediate transfer member;
Transfer means for transferring an image from the intermediate transfer member to the recording medium;
An image forming apparatus comprising:

Images