JP2008213333A - Inkjet recording method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording method and apparatus capable of carrying out high quality printing by preventing coloring agents from sticking to absorbing body due to deterioration of hydrophilicity of the absorbing body. <P>SOLUTION: The inkjet recording method has an ink feeding step discharging inks containing the coloring agents from recording heads (12K, 12C, 12M, 12Y) and allowing them to stick to a medium 16, a solvent absorbing step absorbing solvent ingredients in the inks from the upper side of the medium 16 by bringing a liquid absorbing member 23 having a lyophilic surface into contact with the liquid on the medium 16 after the inks land on the medium in the ink feeding step, a re-lyophilic processing step restoring the lyophilicity of the absorbing member 23 by carrying out processing for making the lyophilic surface of the absorbing member 23 lyophilic again. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inkjet recording method and apparatus, and more particularly, an inkjet recording method capable of performing high-quality inkjet printing by absorbing an excess liquid (solvent) of ink or treatment liquid applied on a recording medium with an absorber. And an apparatus.

  In order to perform high-quality printing by inkjet, a substantially transparent liquid called “treatment liquid” that reacts with the color material in the ink is applied to the recording medium prior to ink droplets containing the color material. Thus, a method of preventing bleeding of the coloring material in the ink and coalescence of the ink liquids (landing interference) is widely known.

  Further, post-treatment of a solvent that has landed in high-quality inkjet printing is known as a major problem. That is, when the landed solvent permeates the recording paper (recording medium), the paper is kinked (called “cuckling”) and the print quality is significantly deteriorated. To solve this problem, a method of evaporating (drying) the solvent by heating is known. However, this method requires a large energy load, and also causes instability of the system (liquid due to drying of ink in the nozzle portion). Inconveniences such as inadequate droplet ejection).

  On the other hand, a method of solvent removal by contact-type absorption of a solvent by an absorber (hereinafter simply referred to as solvent absorption) as disclosed in Patent Document 1 is known.

Patent Document 1 performs solvent absorption using the capillary force of a porous body. By using an absorbent surface having a hydrophilic surface, the coloring material moves only to the absorber without attaching to the absorber surface. The content of (absorbing) is disclosed.
JP 2005-271400 A

  However, the technique described in Patent Document 1 has a problem that the hydrophilicity of the absorber decreases as the absorber is continuously used, and accordingly, the coloring material adheres to the absorber.

  The present invention has been made in view of such circumstances, and high-quality printing can be performed by preventing adhesion of a coloring material to the absorbent body due to a decrease in the lyophilic ability of the absorbent body (liquid-absorbing member). An object is to provide an ink jet recording method and apparatus.

  In order to achieve the above object, an ink jet recording method according to the present invention includes an ink application process in which ink containing a coloring material is ejected from a recording head and adheres to a medium, and the ink lands on the medium by the ink application process. Then, a liquid absorbing member having a lyophilic surface is brought into contact with the liquid on the medium, and a solvent absorbing step of absorbing the solvent component in the ink from the medium, and the lyophilic property of the liquid absorbing member And a re-lyophilic process step of performing a process for re-lyophilicizing the surface to recover the lyophilic ability of the liquid-absorbing member.

  In addition, an ink jet recording apparatus according to the present invention includes a recording head that discharges ink containing a coloring material toward a medium, and a parent that comes into contact with liquid on the medium including ink applied to the medium by the recording head. A liquid-absorbing member that has a liquid surface and absorbs a solvent component in the ink from the medium; and a process for re-lyophilizing the lyophilic surface of the liquid-absorbing member. And a re-lyophilic treatment means for recovering the lyophilic ability.

  According to the present invention, since the lyophilic performance of the surface of the liquid absorbing member that absorbs the solvent component from the medium can be maintained, the adhesion of the coloring material to the liquid absorbing member due to the decrease in the lyophilic performance is suppressed. And high-quality printing can be performed.

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

(First Embodiment: Overall Configuration of Inkjet Recording Apparatus)
FIG. 1 is an overall configuration diagram of an ink jet recording apparatus according to a first embodiment of the present invention. The ink jet recording apparatus 10 of this example is an image forming apparatus that forms an image on a recording medium by forming a color material aggregate by reacting a treatment liquid not containing a color material with an ink containing a color material. Yes, as shown in the figure, an ejection head ("corresponding to a treatment liquid application means", hereinafter referred to as a "treatment liquid head") 11 provided for discharging the treatment liquid, black (K), cyan (C), magenta (M), a printing unit 12 having a plurality of recording heads (hereinafter referred to as “ink heads”) 12K, 12C, 12M, and 12Y provided for ejecting each ink including each color material of yellow (Y); It has.

  The processing liquid storage / loading unit 13 includes a processing liquid tank that stores the processing liquid supplied to the processing liquid head 11, and the processing liquid tank communicates with the processing liquid head 11 via a required pipe line. The processing liquid storage / loading unit 13 includes notifying means (display means, warning sound generating means) for notifying when the remaining amount of the processing liquid is low, and for preventing erroneous loading between liquid types. It has a mechanism.

  The ink storage / loading unit 14 has ink tanks for storing inks of the respective colors corresponding to the ink heads 12K, 12C, 12M, and 12Y, and the tanks 12K, 12C, 12M, 12Y is communicated. Further, the ink storage / loading unit 14 includes notifying means (display means, warning sound generating means) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. ing. Details of the treatment liquid and ink used in this example will be described later.

  The ink jet recording apparatus 10 is opposed to a paper feeding unit 18 that supplies recording paper 16 as a recording medium, a decurling unit 20 that removes curling of the recording paper 16, and a nozzle surface (ink ejection surface) of the printing unit 12. And a belt conveying unit 22 that conveys the recording paper 16 while maintaining the flatness of the recording paper 16, and an absorber (“Liquid Absorption” for absorbing the treatment liquid and the excess solvent of the ink from the recording paper 16. 23 ”, a print detection unit 24 that reads a printing result by the printing unit 12, and a paper discharge unit 26 that discharges recorded recording paper (printed matter) to the outside.

  In FIG. 1, a roll paper (continuous paper) magazine 19 is shown as an example of the paper supply unit 18, but a plurality of magazines having different paper width, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  In the case of an apparatus configuration using roll paper, a cutter 28 is provided as shown in FIG. 1, and the roll paper is cut into a desired size by the cutter 28. The cutter 28 includes a fixed blade 28A having a length equal to or greater than the conveyance path width of the recording paper 16, and a round blade 28B that moves along the fixed blade 28A. The fixed blade 28A is provided on the back side of the print. The round blade 28B is arranged on the print surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

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

  The recording paper 16 delivered from the paper supply unit 18 retains curl due to having been loaded in the magazine 19. In order to remove the curl, heat is applied to the recording paper 16 by the heating drum 30 in the direction opposite to the curl direction of the magazine 19 in the decurling unit 20. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  After the decurling process, the cut recording paper 16 is sent to the belt conveyance unit 22. The belt conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and at least the nozzle surfaces of the heads 11, 12K, 12C, 12M, and 12Y, and the liquid contact surface of the absorber 23 And the part which opposes the sensor surface of the print detection part 24 is comprised so that the horizontal surface (flat surface) may be made.

  The belt 33 has a width that is greater than the width of the recording paper 16, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 1, an adsorption chamber 34 is provided at a position facing the nozzle surfaces of the treatment liquid head 11 and the color ink heads 12K, 12C, 12M, and 12Y on the inner side of the belt 33 spanned between the rollers 31 and 32. The recording paper 16 is sucked and held on the belt 33 by sucking the suction chamber 34 with a fan 35 to a negative pressure. In place of the suction adsorption method, an electrostatic adsorption method may be adopted.

  The power of a motor (not shown) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, whereby the belt 33 is driven counterclockwise in FIG. The recording paper 16 is conveyed in the left direction (sub-scanning direction) in FIG.

  Although a mode using a roller / nip conveyance mechanism in place of the belt conveyance unit 22 can be considered, if the roller / nip conveyance is performed in the printing area, the roller comes into contact with the printing surface of the paper immediately after printing, so that the image blurs. There is a problem that it is easy. Therefore, as in this example, suction belt conveyance that does not contact the image surface in the printing region is preferable.

  In addition, when a borderless print or the like is printed, the ink also adheres to the belt 33. Therefore, the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the print area). Although details of the configuration of the belt cleaning unit 36 are not shown, for example, there are a method of niping a brush roll, a water absorbing roll, etc., an air blowing method of spraying clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  The treatment liquid head 11 and the ink heads 12K, 12C, 12M, and 12Y of the respective colors have lengths corresponding to the maximum paper width of the recording paper 16 targeted by the ink jet recording apparatus 10, and the nozzle surface has a maximum size. This is a full-line type head in which a plurality of nozzles (discharge ports) are arranged over a length exceeding the at least one side of the recording paper 16 (full width Wm of the drawable range).

  As shown in FIG. 1, the ink heads 12K, 12C, 12M, and 12Y are black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side along the feeding direction of the recording paper 16. The processing liquid head 11 is arranged further upstream of the ink head 12K. Each of the heads 11, 12 K, 12 C, 12 M, and 12 Y is fixedly installed so as to extend along a direction substantially orthogonal to the conveyance direction of the recording paper 16.

  With such a head arrangement, the treatment liquid can be attached to the recording surface (printed surface) of the recording paper 16 by the treatment liquid head 11 before the ink heads 12K, 12C, 12M, and 12Y eject ink of each color. . In addition, while the recording paper 16 is conveyed at a constant speed by the belt conveying unit 22, ink is ejected from the ink heads 12K, 12C, 12M, and 12Y toward the recording paper 16 to which the processing liquid is attached, A color image can be formed on the recording paper 16 by reacting to form a color material aggregate.

  As described above, according to the configuration in which the full-line heads 12K, 12C, 12M, and 12Y having nozzle rows that cover the entire width of the paper are provided for each color, the recording paper 16 is moved to the head 12K in the paper feeding direction (sub-scanning direction). , 12C, 12M, and 12Y, an image can be recorded on the entire surface of the recording paper 16 by performing the operation of moving relative to the recording paper 16 only once (that is, by one sub-scanning). Such a single-pass inkjet recording apparatus 10 is capable of high-speed printing as compared with a shuttle (serial) scanning system that performs drawing while reciprocating the recording head in the main scanning direction, and improves print productivity. Can do.

  In this example, the configuration of KCMY 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, special color ink, etc. are used as necessary. May be added. For example, it is possible to add a head for ejecting light-colored ink such as light cyan and light magenta. Also, the arrangement order of the color heads is not particularly limited.

  The absorber 23 disposed in the subsequent stage of the printing unit 12 (downstream in the paper feeding direction) is made of a porous material and contacts the liquid on the recording paper 16 (here, a mixed liquid of processing liquid and ink). The surface to be lyophilic. By bringing the absorber 23 into contact with the liquid on the recording paper 16, excess liquid (solvent) is absorbed from the recording paper 16 by capillary force.

  In addition, the inkjet recording apparatus 10 of the present example is lyophilic with respect to the lyophilic determination unit 38 (equivalent to “lyophilic determination means”) 38 for determining the degree of lyophilicity of the surface of the absorber 23. A lyophilic process part (corresponding to “re-lyophilic process means”) 40 for performing the process and a solvent recovery part 42 for recovering the solvent from the absorber 23 are provided.

  The lyophilic determination unit 38 is a means for detecting the degree of lyophilicity on the surface of the absorber 23 and determining whether or not a lyophilic process is necessary. In this example, the lyophilic determination unit 38 is a means for dropping a certain amount of liquid onto the absorber 23. And a video camera that images the surface of the absorber 23. The state in which the liquid dropped onto the absorber 23 is absorbed by the absorber 23 is photographed with a video camera, and the absorption time is measured based on the obtained electronic image. Determine.

  The lyophilic process part 40 is a means for performing hydrophilic treatment on the surface of the absorber 23 and recovering the lyophilic performance. In this example, a configuration in which a lyophilic solution is applied to the absorber 23 is adopted. ing. Although not shown, a solution storage / loading unit for supplying the lyophilic solution to the lyophilic processing unit 40 is provided, and the solution storage / loading unit has a remaining amount of the lyophilic solution. In addition to providing notifying means (display means, warning sound generating means) for notifying that when the number is reduced, it has a mechanism for preventing erroneous loading between liquid types.

  The solvent recovery unit 42 is a unit that recovers the solvent absorbed by the absorber 23 by the suction force of the pump 43 and recovers the liquid absorption force of the absorber 23. Here, although the example using the pump 43 was shown, after moving another solvent (collection member), such as a nonwoven fabric, to the absorber 23 to move the solvent from the absorber 23 to the collection member, the collection member Is squeezed out with a pressure roller or an elastic blade.

  Alternatively, instead of a configuration in which the solvent is recovered from the outside of the absorber 23, a mode in which a shaft communicating with the suction pump is disposed inside the absorber 23 and the solvent is recovered from the inside of the absorber 23 is also possible. .

  The print detection unit 24 arranged at the subsequent stage of the absorber 23 includes an image sensor for imaging the droplet ejection results from the ink heads 12K, 12C, 12M, and 12Y. From the droplet ejection image read by the image sensor, It functions as a means for checking clogging and other discharge defects.

  The print detection unit 24 is, for example, a CCD line sensor having a light receiving element (photoelectric conversion element) row wider than the droplet discharge width (image recording width in the main scanning direction) by the heads 12K, 12C, 12M, and 12Y. Composed. Instead of the line sensor, an area sensor in which the light receiving elements are two-dimensionally arranged can be used. Further, the method of the image sensor is not limited to the CCD, and other image sensors such as CMOS can be used.

  A test pattern or practical image printed by the ink heads 12K, 12C, 12M, and 12Y of each color is read by the print detection unit 24, and ejection of each head is detected. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like.

  The printed matter generated through the ink droplet ejection by the printing unit 12 and the solvent absorption step by the absorber 23 is ejected from the paper ejection unit 26. Since it is preferable that the original image to be printed (printed target image) and the test print (test pattern, etc.) are discharged separately, the inkjet recording apparatus 10 uses the printed image of the main image and the test print. A sorting means (not shown) for switching the paper discharge path is provided in order to select the printed matter and send it to the respective discharge units 26A and 26B. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by a cutter (second cutter) 48. Although not shown in FIG. 1, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders.

[Head structure]
Next, the structure of the ink head will be described. Since the structures of the ink heads 12K, 12C, 12M, and 12Y for each color are common, the ink heads are represented by the reference numeral 50 in the following.

  2A is a plan perspective view showing an example of the structure of the ink head 50, and FIG. 2B is an enlarged view of a part thereof. FIG. 2C is a perspective plan view showing another example of the structure of the ink head 50. In order to increase the dot pitch printed on the recording paper 16, it is necessary to increase the nozzle pitch in the ink head 50. As shown in FIGS. 2A and 2B, the ink head 50 of this example includes a plurality of ink chamber units (nozzles 51, which are ink discharge ports, and pressure chambers 52 corresponding to the nozzles 51). It has a structure in which droplet ejection elements 53 as recording element units are arranged in a zigzag matrix (two-dimensionally), thereby arranging along the head longitudinal direction (direction perpendicular to the paper feed direction). Thus, the density of the substantial nozzle interval (projection nozzle pitch) projected is increased.

  The configuration in which one or more nozzle rows are formed over a length corresponding to the entire width of the recording paper 16 in a direction substantially orthogonal to the feeding direction of the recording paper 16 is not limited to the illustrated example. For example, instead of the configuration of FIG. 2 (a), short head modules 50 ′ in which a plurality of nozzles 51 are two-dimensionally arranged are arranged in a staggered manner and connected as shown in FIG. 2 (c). A line head having a nozzle row having a length corresponding to the entire width of the recording paper 16 as a whole may be configured by elongating the length.

  The pressure chamber 52 provided corresponding to each nozzle 51 has a substantially square planar shape (see FIGS. 2A and 2B), and the nozzle 51 is provided at one of the diagonal corners. An outlet for supplying ink (supply port) 54 is provided on the other side. The shape of the pressure chamber 52 is not limited to this example, and the planar shape may have various forms such as a quadrangle (rhombus, rectangle, etc.), a pentagon, a hexagon and other polygons, a circle, and an ellipse.

  FIG. 3 is a cross-sectional view showing a three-dimensional configuration of a droplet discharge element for one channel (an ink chamber unit corresponding to one nozzle 51) in the ink head 50 (along line 3-3 in FIG. 2A). FIG.

  As shown in FIG. 3, each pressure chamber 52 communicates with a common flow channel 55 through a supply port 54. The common channel 55 communicates with an ink tank (not shown in FIG. 3; equivalent to the reference numeral 14 in FIG. 1) serving as an ink supply source, and the ink supplied from the ink tank passes through the common channel 55. The pressure chamber 52 is distributed and supplied.

  An actuator 58 having an individual electrode 57 is joined to a pressure plate (vibrating plate also serving as a common electrode) 56 constituting a part of the pressure chamber 52 (the top surface in FIG. 3). By applying a drive voltage between the individual electrode 57 and the common electrode, the actuator 58 is deformed and the volume of the pressure chamber 52 is changed, and ink is ejected from the nozzle 51 due to the pressure change accompanying this. The actuator 58 is preferably a piezoelectric element using a piezoelectric material such as lead zirconate titanate or barium titanate. After the ink is ejected, when the displacement of the actuator 58 returns to its original state, new ink is refilled into the pressure chamber 52 from the common channel 55 through the supply port 54.

  By controlling the driving of the actuator 58 corresponding to each nozzle 51 according to the dot arrangement data generated from the input image, ink droplets can be ejected from the nozzle 51. A desired image can be recorded on the recording paper 16 by controlling the ink ejection timing of each nozzle 51 in accordance with the transport speed while transporting the recording paper 16 in the sub-scanning direction at a constant speed.

  As shown in FIG. 4, the ink chamber units 53 having the above-described structure are latticed in a fixed arrangement pattern along a row direction along the main scanning direction and an oblique column direction having a constant angle θ not orthogonal to the main scanning direction. The high-density nozzle head of this example is realized by arranging a large number in the shape.

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

  When the nozzles are driven by a full line head having a nozzle row having a length corresponding to the entire printable width, (1) all the nozzles are driven simultaneously, (2) the nozzles are sequentially moved from one side to the other. (3) The nozzles are divided into blocks, and the nozzles are sequentially driven from one side to the other for each block, etc., and one line (1 in the width direction of the paper (direction perpendicular to the paper conveyance direction)) Driving a nozzle that prints a line of dots in a row or a line consisting of dots in a plurality of rows is defined as main scanning.

  In particular, when the nozzles 51 arranged in a matrix as shown in FIG. 4 are driven, the main scanning as described in the above (3) is preferable. That is, nozzles 51-11, 51-12, 51-13, 51-14, 51-15, 51-16 are made into one block (other nozzles 51-21,..., 51-26 are made into one block, Nozzles 51-31,..., 51-36 as one block,...), And the nozzles 51-11, 51-12,. One line is printed in 16 width directions.

  On the other hand, by relatively moving the above-mentioned full line head and the paper, printing of one line (a line formed by one line of dots or a line composed of a plurality of lines) formed by the above-described main scanning is repeatedly performed. This is defined as sub-scanning.

  The direction indicated by one line (or the longitudinal direction of the belt-like region) recorded by the main scanning is referred to as a main scanning direction, and the direction in which the sub scanning is performed is referred to as a sub scanning direction. In other words, in the present embodiment, the conveyance direction of the recording paper 16 is the sub-scanning direction, and the direction orthogonal to it is the main scanning direction. In implementing the present invention, the nozzle arrangement structure is not limited to the illustrated example.

  The structure of the treatment liquid head 11 described in FIG. 1 is substantially the same as that of the ink head 50 described above, although not shown. However, since the treatment liquid has only to be applied substantially uniformly (substantially uniformly) to the area where ink is ejected on the recording paper 16, formation of high-density dots is not required as compared with ink. Therefore, the treatment liquid head 11 can be configured to have a smaller number of nozzles (lower nozzle density) than the ink head 50. Further, a configuration in which the nozzle diameter of the treatment liquid head 11 is larger than the nozzle diameter of the ink head 50 is also possible.

[Description of treatment liquid and ink]
The ink used in the inkjet recording apparatus 10 of the present example includes dye ink in which the coloring material is dissolved in a molecular state (may be in an ionic state) in a liquid solvent, and the coloring material is a minute lump in the liquid solvent. Examples thereof include pigment ink dispersed in a state.

  On the other hand, the treatment liquid is a liquid that generates an aggregate of color materials when mixed with ink. Specifically, a treatment liquid that reacts with ink to precipitate or insolubilize the color material in the ink, a treatment liquid that generates a semi-solid substance (gel) containing the color material in the ink, and the like can be given.

  The means for causing the reaction between the ink and the treatment liquid is a method of reacting the anionic coloring material in the ink and the cationic compound in the treatment liquid, or by mixing the ink and the treatment liquid having different pHs with each other. A method of agglomerating the pigment by causing dispersion destruction of the pigment in the ink by changing the pH of the ink, a method of causing the dispersion destruction of the pigment in the ink by reaction with the polyvalent metal salt in the treatment liquid, and the like. is there.

[Processing liquid application method]
As a method for applying the treatment liquid, there is a method in which the recording liquid 16 is uniformly applied (whole surface application) irrespective of ink droplet ejection, but the treatment liquid is also ejected from the head in the same manner as the ink. This is desirable because the treatment liquid can be selectively applied according to the ink droplet ejection position, and the amount of treatment liquid used can be reduced. In this case, it is desirable that the treatment liquid droplet ejection area be large relative to the logical sum of the ink droplet ejection patterns (for example, C, M, Y, K for a four-color image). FIG. 5 is a diagram showing the specifications of the treatment liquid droplet deposition area. For example, consider a case where the ink head 50 ejects dots of ink 62 having a droplet ejection pattern onto the pixels as shown in FIG.

  At this time, as shown in FIG. 5 (b), it is conceivable to apply droplets of the treatment liquid 64 to the upper, lower, left and right pixels in addition to the droplets of the ink 62 dots. Further, as shown in FIG. 5 (c), in addition to the droplet ejection dots of the ink 62, it is also possible to adopt a specification in which dots of the treatment liquid 64 are ejected to the upper, lower, left, and right pixels and all the diagonally located pixels. . Further, as shown in FIG. 5 (d), it is possible to adopt a specification in which four dots are ejected vertically and horizontally at a position shifted by half a pixel with respect to the droplet ejection pixels of the ink 62. Further, as shown in FIG. 5E, the dot diameter of the treatment liquid 64 is made larger than the dot diameter of the ink 62, and the dots of the ink 62 are ejected around the droplet ejection pixels of the ink 62. It is good also as a specification which extends the droplet ejection area | region of the process liquid 28 out of a droplet pixel.

  As described above, by setting the droplet ejection area of the processing liquid 64 as shown in FIG. 5, the entire ink 62 can be reacted with the processing liquid 64.

  In the case of the droplet ejection specification of the treatment liquid 64 shown in FIGS. 5B, 5C, and 5D, the dots of the treatment liquid 64 are united with each other, and as shown in FIG. Thus, it can be considered that the dot becomes one substantially circular dot. FIG. 6 is a diagram showing a combination of the dots of the processing liquid 64 that are formed into one substantially circular dot. FIG. 6A shows the dot of the processing liquid 64 as shown in FIG. 5B. 6 (b) shows a case where a droplet of the treatment liquid 64 is deposited as shown in FIG. 5 (c), and FIG. 6 (c) shows a case where the treatment is performed as shown in FIG. 5 (d). The case where the dot of the liquid 64 was ejected is shown.

[Description of absorber]
Next, the material of the absorber 23 will be described. As the absorber 23, a material used as the absorber 23 may be formed by directly forming holes with a laser or the like. Moreover, you may use the porous body which consists of organic polymers, such as ceramics and a polyurethane, the fabric which woven the fiber, etc. as the absorber 23. FIG.

  In addition, there exists a merit which can improve the durability of the absorber 23 by using a porous body for the absorber 23, and can produce the absorber 23 cheaply by using a fibrous material. Whether the porous body or the fibrous material is used as the absorber 23 is preferably selected as appropriate according to the specifications of the apparatus.

  FIG. 7 is a perspective view showing an example of the absorber 23. As shown in FIG. 7, the absorber 23 has a cylindrical shape, and a contact portion 23A that contacts the liquid on the recording paper 16 (see FIG. 1) is formed on the surface of the cylindrical portion.

  FIG. 8 is a developed view (enlarged view) of the contact portion 23A, and shows two examples. FIG. 8A shows an example in which circular holes (solvent absorption holes 23B) are formed at equal intervals, and FIG. 8B shows an example in which mesh-like holes are formed. In addition, the average value (average diameter φa) of the diameter D of the solvent absorption hole 23B is about 10 to 100 μm.

  Here, as shown to Fig.8 (a), the aperture diameter D of the contact part 23A of the absorber 23 is defined as the diameter of the said hole, when making a hole directly with a laser etc. and using it. Moreover, when using a porous body as the absorber 23, the existing pore diameter distribution measuring apparatus (porosimeter) can be used and it is desirable to obtain | require by the mercury intrusion method. In addition, as shown in FIG. 8B, when the opening is not substantially circular, such as a fibrous substance, it is desirable to define the diameter of the circumscribed circle of the opening as the diameter D.

  In addition, the above is described about the diameter D of the solvent absorption hole 23B of the contact part 23A of the absorber 23, and the diameters other than the contact part (the inner side of the absorber and the opposite side of the contact part) are arbitrarily determined. I can do it. Preferably, the inner portion of the absorbent body 23 has an effect that the absorption speed at the central portion is faster when the diameter is larger than that of the contact portion 23A.

[Description of lyophilic treatment method]
As a method for making the surface of the absorber 23 lyophilic, there is a method such as plasma treatment of the surface, but it absorbs a liquid (hereinafter referred to as a hydrophilization promoting solution) in which fine particles that exhibit lyophilicity are dispersed in a solvent. It is most convenient to express by applying to the body 23. Examples of the fine particles include hydrophilic fine particles such as silica (SiO ₂ ) fine particles, and fine particles that become lyophilic (so-called photocatalyst) when irradiated with specific light such as titanium dioxide (TiO ₂ ). Can be used. In the latter case, it is necessary to provide a device for irradiating light (for example, ultraviolet light) of an appropriate wavelength after applying the lyophilic solution to the absorber 23.

  In addition, as a method for applying the lyophilic solution, the solution may be directly applied to the absorber 23 (for example, spray injection), or after the lyophilic solution is applied to the belt conveyance unit 22, the absorber 23 is used. There is also a method in which the absorbent 23 absorbs the lyophilic solution by contacting with the belt conveying unit 22.

  FIG. 9 is a schematic view in which fine particles 66 for imparting lyophilicity are imparted to the absorber 23. FIG. 9 shows an example of an absorber having holes (solvent absorption holes 23B) formed at equal intervals, and FIG. 10 is an example of an absorber using a mesh. In these drawings, the fine particles 66 are drawn larger than the actual size.

Next, a preferable diameter of the fine particles 66 will be described. If the diameter of the fine particles 66 is larger than a certain size when compared with the diameter of the contact portion 23A of the absorber 23, the fine particles 66 block the solvent absorption holes 23B of the absorber 23, thereby significantly reducing the absorption capacity of the absorber 23. It may end up. Therefore, when the diameter of the fine particles 66 is φp and the average diameter of the contact portion 23A of the absorber 23 is φa, the following formula φp ≦ φa / 200 (Equation 1)
It is preferable to satisfy.

Further, in the process of absorbing the solvent, the fine particles 66 attached to the absorber 23 may be transferred to the printing surface side. In that case, if the diameter of the fine particles 66 is large, the density of the image may decrease due to the light scattering effect. Generally, if the particle diameter is 1/5 or less of the wavelength of light, more preferably 1/10 or less, light scattering can be almost ignored. Since the absorption wavelength of the dye of a normal printer is about 400 to 700 nm, in order to prevent light scattering by the fine particles 66, the diameter φp of the fine particles 66 is expressed by the following equation: φp ≦ 80 nm (Equation 2)
Is satisfied, image quality deterioration due to light scattering by the fine particles 66 is reduced. Even more preferably, the following formula φp ≦ 40 nm (Equation 3)
Is satisfied, image quality deterioration due to light scattering by the fine particles 66 is almost eliminated.

On the other hand, if the size of the fine particles 66 is too small, even if the lyophilic solution is applied, the fine particles 66 do not adhere to the vicinity of the contact portion 23A of the absorber 23 and the lyophilic ability is not expressed. In order to develop lyophilicity, the following formula φp ≧ φa / 5000 ... [Formula 4]
It is preferable to satisfy.

Next, physical properties of the hydrophilization promoting solution will be described. In this case, the surface tension of the hydrophilization promoting solution is γ _H , the viscosity is η _H , the surface tension of the solvent component of the aggregated ink (the liquid obtained by filtering the mixture of the ink and the processing liquid and extracting only the solvent component) is γ _I , When the viscosity is η _I , the following formula γ _H / η _H <γ _I / η _I [Equation 5]
It is preferable to satisfy. By setting the values in this way, the lyophilic solution can penetrate more into the absorber 23 than the solvent component of the aggregated ink, and the absorber 23 can be appropriately lyophilic.

[Time of lyophilic treatment]
As for the timing (timing) for carrying out the lyophilic treatment, there are a method of executing it after a predetermined time has passed and a method of executing it after printing a predetermined number of sheets. The lyophilic determination unit 38 for determining the lyophilic degree of 23 is provided, and the above-described lyophilic process is executed only when the lyophilic determination unit 38 determines that it is necessary. An example of the control flow in this mode is shown in FIG.

  As described above, when a porous body is used as the absorber 23, it is difficult to measure the lyophilicity by the contact angle. Therefore, it is preferable to determine the degree of lyophilicity by preferably applying a certain amount of liquid to the absorber 23 and measuring the time (absorption time t) until they are all absorbed (step S12). . The absorption time t is measured by taking a picture of how the dropped liquid is absorbed with a video camera or the like, and the time from when the liquid is applied to the surface of the absorber 23 until the liquid disappears from the surface of the absorber 23, There are methods such as automatic acquisition by image processing, or calculation by the user actually viewing the video.

  The liquid used here may be any liquid as long as the absorption time varies depending on the hydrophilicity of the surface of the absorber. For example, a processing liquid used for drawing may be used.

  The absorption time t obtained by the measurement in step S12 is compared with a predetermined determination reference value t0 (predetermined specified value) (step S14). If t ≦ t0 is not satisfied, that is, the absorption time t is determined. If the reference value t0 is exceeded (NO in step S14), the lyophilic process is executed (step S16), and the flow is terminated.

  On the other hand, if t ≦ t0 is satisfied in step S14 (YES determination), the lyophilic process is not executed and the flow ends.

  In addition to the above embodiment, the amount of lyophilic liquid in the absorber depends on the amount of solvent absorbed (the amount of solvent absorbed decreases as the lyophilic level decreases), and the amount of solvent remaining in the solvent-treated medium is measured. There is also a method of determining the hydrophilicity of the absorber from there.

  For example, when the solvent is water, water molecules absorb light in the infrared region, and therefore the amount of residual solvent can be calculated from the reflectance of infrared light. That is, a method of calculating the amount of solvent absorbed from the ratio of reflectance values to infrared light before and after solvent removal, and lyophilizing the absorber when the amount of absorbed solvent is below a threshold value It is. This method makes it possible to measure the hydrophilization of the absorber during printing (online). Details of this aspect will be described later as a second embodiment.

[Explanation of control system]
FIG. 12 is a block diagram showing a system configuration of the inkjet recording apparatus 10. As shown in the figure, the inkjet recording apparatus 10 includes a communication interface 70, a system controller 72, an image memory 74, a ROM 75, a motor driver 76, a heater driver 78, a print control unit 80, an image buffer memory 82, a head driver 84, and the like. It has.

  The communication interface 70 is an interface unit (image input unit) that functions as an image input 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.

  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 image memory 74. The image memory 74 is a storage unit that stores an image input via the communication interface 70, and data is read and written through the system controller 72. The image 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 the communication interface 70, the image memory 74, the motor driver 76, the heater driver 78, and the like, and performs communication control with the host computer 86, read / write control of the image memory 74 and the ROM 75, and the like. At the same time, a control signal for controlling the motor 88 and the heater 89 of the transport system is generated.

  The ROM 75 stores programs executed by the CPU of the system controller 72 and various data necessary for control (including measurement test pattern data such as landing position errors). The ROM 75 may be a non-rewritable storage means, or may be a rewritable storage means such as an EEPROM.

  The image 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 (driving circuit) that drives the conveyance motor 88 in accordance with an instruction from the system controller 72. The heater driver 78 is a driver that drives a heater 89 such as a heating fan in accordance with an instruction from the system controller 72.

  Under the control of the system controller 72, the print control unit 80 performs various processes such as processing and correction for generating a droplet ejection control signal from image data (multi-value input image data) in the image memory 74. In addition to functioning as a signal processing unit, the generated ink discharge data is supplied to the head driver 84 to function as a drive control unit that controls the discharge drive of the ink head 50.

  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. In FIG. 12, the image buffer memory 82 is shown in a mode associated with the print control unit 80, but it can also be used as the image memory 74. Also possible is an aspect in which the print controller 80 and the system controller 72 are integrated and configured with one processor.

  An overview of the flow of processing from image input to print output is as follows. Image data to be printed is input from the outside via the communication interface 70 and stored in the image memory 74. At this stage, for example, RGB multivalued image data is stored in the image memory 74.

  In the ink jet recording apparatus 10, a pseudo continuous tone image is formed by changing the droplet ejection density and dot size of fine dots with ink (coloring material) to the human eye. It is necessary to convert to a dot pattern that reproduces the gradation (shading of the image) as faithfully as possible. For this reason, the original image (RGB) data stored in the image memory 74 is sent to the print controller 80 via the system controller 72 and converted into dot data for each ink color.

  That is, the print control unit 80 performs a process of converting the input RGB image data into dot data of four colors K, C, M, and Y. Thus, the dot data generated by the print control unit 80 is stored in the image buffer memory 82. The dot data for each color is converted into CMYK droplet ejection data for ejecting ink from the nozzles of the ink head 50, and the ink ejection data to be printed is determined. Further, the dot data of the treatment liquid is generated from the dot data for each color by the above-described method.

  The head driver 84 drives the actuators 58 corresponding to the nozzles 51 of the ink head 50 and the treatment liquid head 11 according to the print contents based on the ink discharge data and the drive waveform signal given from the print control unit 80. A drive signal is output. The head driver 84 may include a feedback control system for keeping the head driving conditions constant.

  In this way, when the drive signal output from the head driver 84 is applied to the ink head 50 or the processing liquid head 11, the ink or the processing liquid is ejected from the corresponding nozzle 51. An image is formed on the recording paper 16 by controlling ink ejection from the ink head 50 and the treatment liquid head 11 in synchronization with the conveyance speed of the recording paper.

  As described above, ink or processing liquid droplets from the nozzles via the head driver 84 based on ink and processing liquid ejection data and drive signal waveforms generated through the required signal processing in the print controller 80. The discharge amount and the discharge timing are controlled. Thereby, a desired dot size and dot arrangement are realized.

  As described with reference to FIG. 1, the print detection unit 24 is a block including an image sensor, reads an image printed on the recording paper 16, performs necessary signal processing, etc. And the detection result is provided to the print controller 80 and the system controller 72.

  The print control unit 80 performs various corrections on the ink head 50 based on information obtained from the print detection unit 24 as necessary, and also performs cleaning operations (nozzle recovery operation) such as preliminary ejection, suction, and wiping as necessary. Control to implement.

  In addition, the inkjet recording apparatus 10 of the present example includes a measurement liquid application unit 91 (corresponding to “measurement liquid application unit”) that applies an absorption time measurement liquid to the absorber 23 (see FIG. 1), A lyophilic determination unit 38 is provided that includes a video camera 92 for photographing a state in which the liquid applied from the measurement liquid applying unit 91 onto the absorber 23 soaks into the absorber 23.

  The image signal obtained from the video camera 92 is sent to the image processing unit 94, and the time (absorption time) until the liquid runs out from the surface of the absorber 23 is measured by image processing in the image processing unit 94. That is, in this example, the combination of the video camera 92, the image processing unit 94, and the system controller 72 functions as a “measuring unit” for measuring the absorption time.

  The system controller 72 determines whether or not the lyophilic process is necessary based on the absorption time information automatically acquired from the image processing of the image processing unit 94. On the other hand, a command for executing a lyophilic process (here, a process of applying the lyophilic solution to the absorber 23) is output. That is, the system controller 72 executes the control flow described with reference to FIG.

[Description of dot formation process from ink ejection to solvent removal]
Here, the dot formation process by the inkjet recording apparatus 10 of the present example will be described with reference to FIG. FIG. 13 schematically shows a series of steps from ink droplet ejection to solvent removal. As shown in FIG. 13A, after the treatment liquid 64 is ejected onto the recording paper 16, the ink 62 including the color material 97 is ejected. Then, after the ink 62 has landed on the recording paper 16 as shown in FIG. 13B, the aggregation reaction of the color material 97 in the ink 62 proceeds by the action of the treatment liquid 64 as shown in FIG. 13C. At the same time, the solvent of the ink 62 is mixed with the solvent of the treatment liquid 64. Thereafter, as shown in FIG. 13D, the aggregation reaction of the color material 97 is completed, and a mixed liquid composed of the solvent 98 and the color material aggregate 101 is generated on the recording paper 16.

  Since the color material aggregate 101 formed at this time has a specific gravity greater than that of the solvent 98 and is not dissolved (or dispersed) in the solvent 98, the color material aggregate 101 is in close contact between the color material aggregate 101 and the recording paper 16. The color material aggregate 101 is temporarily fixed to the recording paper 16.

  As shown in FIG. 13E, the absorber 23 is brought close to the recording paper 16, the contact portion 23A of the absorber 23 is brought into contact with the solvent 98, and the solvent 98 is absorbed and removed by the solvent absorption hole 23B. In order to completely remove the solvent 98, it is desirable that the contact portion 23A of the absorber 23 is in contact with the recording paper 16.

  As described above, as shown in FIG. 13F, only the color material aggregate 101 is left on the recording paper 16, and dots (images) of the color material aggregate 101 are recorded on the recording paper 16.

  The contact portion 23A of the absorbent body 23 in this example is subjected to lyophilic processing by the lyophilic processing unit 40 according to the determination by the lyophilic determination unit 38 described in FIG. 1, and the required lyophilic performance is maintained for the contact portion 23A. Therefore, the color material 97 does not adhere to the absorber 23 when the absorber 23 is retracted (separated) from the recording paper 16 after absorbing the solvent.

(Second Embodiment)
FIG. 14 is a configuration diagram of the ink jet recording apparatus 110 according to the second embodiment, and FIG. 15 is a block diagram showing the system configuration. 14 and 15, the same or similar elements as those shown in FIGS. 1 and 12 are denoted by the same reference numerals, and description thereof is omitted.

  In the inkjet recording apparatus 110 according to the second embodiment shown in FIG. 14, instead of the configuration of the lyophilic determination unit 38 in the inkjet recording apparatus 10 of FIG. 1, as shown in FIG. Infrared detectors 115 and 117 are provided on the sides.

  As shown in FIG. 15, the infrared detectors 115 and 117 include infrared light emitting elements 115A and 117A and infrared light receiving elements 115B and 117B. The infrared light emitting elements 115A and 117A are directed toward the recording paper 16 surface. The infrared light receiving elements 115B and 117B receive the reflected light of the irradiated light (infrared rays).

  Since the amount of absorption of light in the infrared region varies depending on the amount of solvent present on the recording paper 16, the amount of residual solvent can be calculated from the reflectance of infrared light measured by each of the infrared detectors 115 and 117. It is. Table data indicating the relationship (correlation) between the reflectance and the residual solvent amount may be stored in a memory, and the residual solvent amount may be obtained by referring to the table, or an arithmetic expression indicating the correlation between the two may be used. You may calculate.

  Based on the information (detection signal output according to the amount of received light) obtained from the infrared detector 115 arranged on the upstream side of the absorber 23, the residual solvent amount before solvent removal (absorption processing) by the absorber 23 is calculated. Is done. In addition, based on information obtained from the infrared detection unit 117 disposed on the downstream side of the absorber 23 (detection signal output according to the amount of received light), the residual solvent amount after solvent removal (absorption processing) by the absorber 23 Is calculated.

  The amount of solvent absorbed by the absorber 23 is calculated from the ratio of the reflectance values to the infrared light before and after the solvent removal, and the value is set to a predetermined threshold value (a predetermined value for a predetermined criterion). Compare with As a result of this comparison, if the amount of solvent absorbed by the absorber 23 is less than or equal to the threshold value, it is determined that the lyophilic degree of the absorber 23 has decreased, and the lyophilic process by the lyophilic processing unit 40 is performed. Is determined to be necessary, and lyophilic processing is executed based on the determination.

  Note that the reflectance value and the residual solvent amount value are calculated in the course of calculation for determining the necessity of lyophilic treatment, and it is not always necessary to obtain these values themselves. In short, it is only necessary to estimate (specify) the amount of solvent absorbed by the absorber 23 from information reflecting the amount of residual solvent before and after solvent removal, and the specific means is not limited to the above example.

  In the first and second embodiments described above, the ink jet recording apparatus of a method (direct recording method) in which an ink droplet is directly formed on a recording medium such as recording paper has been described. The scope of application is not limited to this.

(Third embodiment)
FIG. 16 is a configuration diagram of an inkjet recording apparatus 210 according to the third embodiment. The form of the ink jet recording apparatus 210 shown in FIG. 16 does not directly form an image on a recording medium, but once forms an image (primary image) on the intermediate transfer member 232, and the image is a recording paper as a recording medium. 16 is an image forming apparatus of a method (intermediate transfer method) in which final image formation is performed by transferring to image 16. In FIG. 16, elements that are the same as or similar to those in FIG.

  In the ink jet recording apparatus 210 shown in FIG. 16, a rotary drum is used as the intermediate transfer member 232, but an embodiment using an endless belt member is also possible. Below the intermediate transfer member 232, a transfer roller 234 as a transfer unit is disposed to face the intermediate transfer member 232.

  Around the intermediate transfer member 232, along the rotation direction (counterclockwise rotation direction in FIG. 16), the ink cleaning unit 240, the treatment liquid application unit 242, and the ink heads 12C, 12M, and 12Y are sequentially arranged from the transfer roller 234. , 12K, and the absorber 23 is disposed.

  The ink cleaning means 240 is for removing an image once recorded on the intermediate transfer body 232, and is made of a soft material made of sponge or soft fiber so as not to damage the surface of the intermediate transfer body 232. is there.

  The treatment liquid application unit 242 applies the treatment liquid onto the intermediate transfer body 232 prior to the ink ejection of the ink heads 12C, 12M, 12Y, and 12K. Here, a mode in which the processing liquid is applied to the entire surface of the image forming region of the intermediate transfer member 232 by the roller 242A is employed, but the processing liquid head 11 is used to process the processing liquid as in the examples of FIGS. It is also possible to attach the material.

  Ink heads 12C, 12M, 12Y, and 12K shown in FIG. 16 are arranged above intermediate transfer body 232 (in FIG. 16, directly above the side opposite to transfer roller 234). Each of the ink heads 12C, 12M, 12Y, and 12K is a full-line type head having a length corresponding to the maximum image formable width in the axial direction (perpendicular to the paper surface in the drawing) of the intermediate transfer body 232. Along the axial direction of the body 232, the longitudinal direction thereof is arranged in a direction substantially orthogonal to the rotation direction of the intermediate transfer body 232 (direction substantially parallel to the axial direction of the intermediate transfer body 232). In addition, it is preferable that the nozzle surface of each head has a curved shape in accordance with the circumference of the intermediate transfer member 232 in the short side direction.

  The absorber 23 contacts the intermediate transfer member 232 and absorbs the solvent by capillary force. A solvent recovery roller (collection member) 244 for recovering the solvent from the absorber 23 is provided on the side opposite to the contact portion of the absorber 23. The solvent is moved from the absorber 23 to the solvent recovery roller 244 by bringing the solvent recovery roller 244 into contact with the absorber 23. Thereby, the solvent absorptive power of the absorber 23 can be maintained. In addition, you may provide the means to collect | recover a solvent further from the solvent collection | recovery roller 244, and you may make it the structure which replace | exchanges the solvent collection | recovery roller 244 which collect | recovered the fixed amount solvent suitably.

  A lyophilic determination unit 38 and a lyophilic processing unit 40 are provided around the absorber 23, and the lyophilic process (re-lyophilic process) on the surface of the absorber 23 is similar to the example described in FIG. ) Is performed. The effects of the lyophilic treatment are as described in the example of FIG.

  In the ink jet recording apparatus 210 shown in FIG. 16, after the treatment liquid is applied onto the intermediate transfer body 232 by the treatment liquid application unit 242, the ink is ejected from each of the ink heads 12C, 12M, 12Y, and 12K to thereby transfer the intermediate transfer body. A color image (primary image) is formed on H.232. This primary image is moved in the counterclockwise direction on FIG. 16 with the rotation of the intermediate transfer member 232, and excess solvent components are removed by the absorber 23.

  Then, the recording paper 16 is conveyed in synchronization with the rotation of the intermediate transfer body 232, the recording paper 16 is sandwiched between the intermediate transfer body 232 and the transfer roller 234, and is pressurized with a predetermined pressure (nip pressure). The primary image on the transfer body 232 is transferred to the recording paper 16. Thus, the image (secondary image) is transferred and formed on the recording paper 16, and the generated printed matter (recording paper 16 on which the image is formed) is discharged from the paper discharge unit 26.

  In the case of the intermediate transfer method, since the medium is determined, the error factor during the solvent treatment can be reduced as compared with the direct recording method. The error factors include unevenness of the recording medium, wettability (surface energy) of the recording medium, and frictional force between the recording medium and the intermediate.

(Fourth embodiment)
FIG. 17 is a configuration diagram of the main part of the fourth embodiment of the present invention. In FIG. 17, only the structure of a solvent absorption part is shown typically. In FIG. 17, elements that are the same as or similar to those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  The example of FIG. 17 includes a plurality of (two in the figure) absorbers for absorbing the solvent from the recording paper 16, and the plurality of absorbers 23-1 and 23-2 include a moving mechanism (not shown). Thus, it is possible to move between the solvent absorption position (the position in contact with the recording paper 16) and the processing position of the lyophilic processing unit 250 at the position retracted from the position. In the figure, reference numeral 254-1 is a solvent recovery roller for contacting the absorber 23-1 and recovering the solvent from the absorber 23-1, and reference numeral 254-2 is the contact with the absorber 23-2. And a solvent recovery roller for recovering the solvent from the absorber 23-2.

  According to the above configuration, when one of the absorbers (for example, 23-1) is retracted to the processing position and the lyophilic process is performed in the lyophilic processing unit 250, the other absorber (for example, 23-2) is used. ) Can be positioned at the solvent absorption position, and the solvent absorption process can be carried out, and the absorbers 23-1 and 23-2 are alternately re-lyophilic without interrupting the print process (while continuing printing). can do.

  The timing for performing the re-lyophilic process may be after a certain time (time management) or after a certain number of printed sheets (number management). In the case where the re-lyophilic process is performed based on the time and the number of prints, the lyophilic determination unit 38 for detecting the degree of lyophilicity of the absorbers 23-1 and 23-2 can be omitted.

  The configuration shown in FIG. 17 can be applied to the ink jet recording apparatus as shown in FIGS.

  In the above embodiment, the inkjet recording apparatus using the treatment liquid has been exemplified. However, the application range of the present invention is not limited to this example, and a configuration without using the treatment liquid is also possible.

[Appendix]
As can be understood from the description of the embodiments of the invention described in detail above, the present specification includes disclosure of various technical ideas including the invention described below.

  Invention (1): An ink application process in which ink containing a coloring material is ejected from a recording head and adhered to a medium, and an ink having a lyophilic surface after the ink has landed on the medium in the ink application process. The liquid member is brought into contact with the liquid on the medium, a solvent absorption step for absorbing the solvent component in the ink from the medium, and a process for re-lyophilizing the lyophilic surface of the liquid absorbing member, And a re-lyophilic process step for recovering the lyophilic ability of the liquid-absorbing member.

  According to the present invention, the surface of the liquid absorbing member can always be made lyophilic, and adhesion of the coloring material to the liquid absorbing member can be prevented.

  Invention (2): It has the process liquid provision process which provides the said liquid with the process liquid which reacts with the said ink and aggregates the coloring material in the said ink, and the said solvent after the said process liquid application process and the said ink application process The ink jet recording method according to the invention (1), wherein an absorption step is performed.

  According to the aspect of the invention (2), since the color material and the solvent component can be effectively separated, the color material is more difficult to adhere to the liquid absorbing member. Thereby, landing interference and bleeding can be avoided.

  The treatment liquid applying means includes, for example, a means for ejecting the treatment liquid as droplets using an ink jet type liquid discharge head (by ejection from an ink jet nozzle), a roller, a brush, a blade-like member, a porous material, etc. There are modes such as a means for applying the processing liquid using a member or the like, a means for spraying and attaching the processing liquid in a spray form, or an appropriate combination thereof.

  Invention (3): The said re-lyophilic process process re-lyophilicizes the said liquid absorption member by providing a lyophilic promotion solution to the said liquid absorption member. Invention (1) or (2) description characterized by the above-mentioned. Inkjet recording method.

  According to the aspect of the invention (3), the liquid-absorbing member can be easily made lyophilic.

  Invention (4): The ink-jet recording method according to invention (3), wherein the lyophilic promoting solution is a dispersion of fine particles exhibiting lyophilic performance.

  According to the aspect of invention (4), a lyophilic promotion solution can be produced simply.

  Invention (5): The ink jet recording method according to invention (4), wherein the fine particles are a photocatalytically active substance that exhibits lyophilic performance by absorbing light.

  According to the aspect of invention (5), a lyophilic promotion solution can be produced simply.

  Invention (6): The liquid-absorbing member is a porous body, and when the average particle diameter of the fine particles is φp and the average diameter of the contact portion of the liquid-absorbing member with the liquid on the medium is φa, φp ≦ φa / 200 is satisfied, The ink jet recording method according to the invention (4) or (5).

  According to the aspect of the invention (6), since the fine particles contained in the lyophilic solution do not block the absorption holes of the liquid absorbing member, effective solvent absorption is possible.

  Invention (7): Any one of the inventions (4) to (6), wherein the liquid-absorbing member is a porous body and satisfies the following condition: φp ≦ 80 nm when the average particle diameter of the fine particles is φp 2. The ink jet recording method according to item 1.

  According to the aspect of the invention (7), even when the fine particles contained in the lyophilic promotion solution adhere to the printed image, there is little deterioration in the image quality.

  Invention (8): The ink jet recording method according to the invention (7), wherein the liquid-absorbing member is a porous body, and φp ≦ 40 nm is satisfied when the average particle diameter of the fine particles is φp.

  According to the aspect of the invention (8), even when the fine particles contained in the lyophilic promotion solution adhere to the printed image, there is almost no deterioration in image quality.

  Invention (9): The liquid-absorbing member is a porous body, and satisfies the following condition: φp ≧ φa / 5000 when the average particle diameter of the fine particles is φp and the average diameter of the contact portion of the absorber with the solvent is φa An ink jet recording method according to the invention (4) or (5).

  According to the aspect of the invention (9), the fine particles exhibiting lyophilicity can be efficiently attached to the contact portion of the liquid absorbing member.

Invention (10): When the surface tension of the hydrophilization promoting solution is γ _H , the viscosity is η _H , the surface tension of the solvent component of the ink after reaction is γ _I , and the viscosity is η _I , γ _H / η _H < The inkjet recording method according to any one of inventions (3) to (9), wherein γ _I / η _I is satisfied.

  According to the aspect of the invention (10), the lyophilic solution can be penetrated more into the interior than the solvent component of the ink.

  Invention (11): It has a lyophilic determination step of determining the lyophilicity of the surface of the liquid absorbing member, and when the lyophilic processing step determines that the lyophilic processing step is necessary, the re-lyophilic processing step The inkjet recording method according to any one of inventions (1) to (10), wherein the inkjet recording method is carried out.

  According to the aspect of the invention (11), the surface of the liquid absorbing member can be made lyophilic at an appropriate timing.

  Invention (12): The ink-jet recording method according to invention (11), wherein the lyophilic determination step includes a step of dropping a predetermined amount of liquid onto the liquid-absorbing member and measuring the absorption time.

  According to the aspect of the invention (12), the lyophilic determination of the liquid absorbing member can be easily performed.

  Invention (13): The lyophilic determination step is a method for determining the lyophilicity of the liquid absorbing member based on the amount of solvent adhering to the medium before and after the solvent absorption step. The ink jet recording method according to the invention (11).

  According to the aspect of the invention (13), the lyophilic determination of the liquid absorbing member can be performed online.

  Invention (14): Any of the inventions (1) to (13), wherein the medium is a recording medium, and the ink application step directly deposits the ink ejected from the recording head onto the recording medium. The ink jet recording method according to claim 1.

  The aspect of the invention (14) specifies application to a so-called direct recording type inkjet recording method.

  Invention (15): Inventions (1) to (13) are characterized in that the medium is an intermediate transfer member, and includes a transfer step of transferring the color material of the ink adhered on the intermediate transfer member to a recording medium. The inkjet recording method according to any one of the above.

  The aspect of the invention (14) specifies application to a so-called intermediate transfer type ink jet recording method.

  Further, the present specification discloses an invention of an apparatus that embodies the method invention described in the above inventions (1) to (14). For example, an ink jet recording apparatus according to the following inventions (16) to (23) is provided.

  Invention (16): It has a recording head for discharging ink containing a coloring material toward the medium, and a lyophilic surface that comes into contact with the liquid on the medium containing the ink applied to the medium by the recording head. Then, a liquid absorbing member that absorbs the solvent component in the ink from the medium and a lyophilic surface of the liquid absorbing member are re-lyophilic to restore the lyophilic ability of the liquid absorbing member. An ink-jet recording apparatus comprising: a re-lyophilic process means.

  As a configuration example of the recording head (ink discharge means), a full-line head in which a plurality of nozzles are arranged over a length corresponding to the entire width of the medium (recording medium or intermediate transfer member) can be used. In this case, a plurality of relatively short recording head modules having nozzle rows that do not reach the length corresponding to the entire width of the medium are combined, and these are connected to form a nozzle row having a length corresponding to the entire width of the medium as a whole. There are modes to configure.

  A full-line type head is usually arranged along a direction orthogonal to the relative feed direction (relative transport direction) of the medium, but has a predetermined angle with respect to the direction orthogonal to the transport direction. There may be a mode in which the recording head is arranged along the inclined direction.

  When a color image is formed by an inkjet head, a recording head may be arranged for each color of a plurality of colors (recording liquids), or a configuration in which a plurality of colors of ink can be discharged from one recording head may be adopted. .

  The present invention is not limited to the full-line head described above, but can also be applied to shuttle scan type recording heads (recording heads that perform droplet ejection while reciprocating in a direction substantially perpendicular to the recording medium conveyance direction). It is.

  The “medium” may be a recording medium or an intermediate transfer member. The “recording medium” is a medium to which liquid ejected from a liquid ejection head (recording head) adheres, and receives an image recording by the action of the recording head. That is, the “recording medium” can be called a printing medium, an image forming medium, a recording medium, an image receiving medium, an ejected medium, and the like, a continuous sheet, a cut sheet, a seal sheet, a resin sheet such as an OHP sheet, It includes various media, regardless of the material and shape, such as a printed board on which a film, cloth, wiring pattern or the like is formed.

  The “conveying means” is a mode in which the medium is transported to the stopped (fixed) recording head, a mode in which the recording head is moved with respect to the stopped medium, or a mode in which both the recording head and the medium are moved. Both are included.

  Invention (17): It has processing liquid application means for applying a processing liquid that reacts with the ink to agglomerate the color material in the ink to the medium, and the liquid absorbing member is formed by the processing liquid application means by the medium. The inkjet recording apparatus according to invention (16), wherein the inkjet recording apparatus is in contact with the liquid on the medium containing the treatment liquid applied to the medium.

  Invention (18): The ink-jet recording apparatus according to invention (16) or (17), wherein the re-lyophilic treatment means imparts a lyophilic solution to the liquid-absorbing member.

Invention (19): A lyophilic determination means for determining the lyophilicity of the surface of the liquid absorbing member;
Control means for performing control to execute re-lyophilic processing by said re-lyophilic processing means when said lyophilic determination means determines that lyophilic processing is necessary. Invention (16) To (18). The inkjet recording apparatus according to any one of (18).

  Invention (20): The lyophilic determination means measures a measuring liquid applying means for applying a certain amount of liquid to the liquid absorbing member, and an absorption time of the liquid applied to the liquid absorbing member by the measuring liquid applying means. And an ink jet recording apparatus according to the invention (19).

  Invention (21): The lyophilic determination means includes an amount of solvent adhering to the medium before absorbing the solvent by the liquid absorbing member and an amount of solvent adhering to the medium after absorbing the solvent by the liquid absorbing member. The ink-jet recording apparatus according to the invention (19), wherein the lyophilicity of the liquid-absorbing member is determined on the basis of the difference.

  Invention (22): The medium is a recording medium, and the ink ejected from the recording head is directly landed on the recording medium to record dots of the color material on the recording medium. The ink jet recording apparatus according to any one of inventions (16) to (21).

  Invention (23): The invention (16), comprising: an intermediate transfer member as the medium; and transfer means for transferring the color material of the ink deposited on the intermediate transfer member to a recording medium. To (21). The inkjet recording apparatus according to any one of (21).

1 is an overall configuration diagram of an ink jet recording apparatus according to a first embodiment of the present invention. Plane perspective view showing structural example of head Sectional drawing which follows the 3-3 line in FIG. Enlarged view showing the nozzle arrangement of the head Diagram showing the specifications of the treatment liquid droplet deposition area The figure which shows the union of processing liquid dot External view of absorber Expanded view of the absorber contact area (enlarged view) Schematic diagram of an example in which fine particles for lyophilicity are given to the absorber Schematic diagram of another example in which fine particles for lyophilicity are given to the absorber A flowchart showing an example of a control procedure of lyophilic processing 1 is a block diagram showing a system configuration of an ink jet recording apparatus according to a first embodiment. Schematic diagram showing a series of actions to form a color material aggregate by treatment liquid and ink droplets and remove the solvent FIG. 2 is an overall configuration diagram of an ink jet recording apparatus according to a second embodiment of the present invention. FIG. 2 is a block diagram showing a system configuration of an ink jet recording apparatus according to a second embodiment. FIG. 5 is an overall configuration diagram of an ink jet recording apparatus according to a third embodiment of the present invention. The principal part block diagram which shows the 4th Embodiment of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,110,210 ... Inkjet recording device, 11 ... Processing liquid head, 12 ... Printing part, 12K, 12C, 12M, 12Y ... Ink head, 16 ... Recording paper, 23 ... Absorber, 23A ... Contact part, 23B ... Solvent Absorption hole, 38 ... lyophilic determination unit, 40 ... lyophilic processing unit, 62 ... ink, 64 ... treatment liquid, 66 ... fine particles, 97 ... color material, 98 ... solvent, 101 ... color material aggregate

Claims (23)

An ink application process in which ink containing a coloring material is ejected from a recording head and adhered to a medium;
After the ink has landed on the medium in the ink application step, the liquid absorption member having a lyophilic surface is brought into contact with the liquid on the medium, and the solvent absorption absorbs the solvent component in the ink from the medium. Process,
A process for re-lyophilicizing the lyophilic surface of the liquid-absorbing member, and re-lyophilic processing step for recovering the lyophilic ability of the liquid-absorbing member;
An ink jet recording method comprising: A treatment liquid application step of applying a treatment liquid that reacts with the ink to agglomerate the coloring material in the ink to the medium;
The inkjet recording method according to claim 1, wherein the solvent absorption step is performed after the treatment liquid application step and the ink application step.   3. The ink jet recording method according to claim 1, wherein in the re-lyophilic process step, the liquid-absorbing member is re-lyophilic by applying a lyophilic solution to the liquid-absorbing member. 4.   4. The ink jet recording method according to claim 3, wherein the lyophilic promoting solution is obtained by dispersing fine particles exhibiting lyophilic performance.   5. The ink jet recording method according to claim 4, wherein the fine particles are a photocatalytically active substance that exhibits lyophilic performance by absorbing light. The liquid absorbing member is a porous body,
When the average particle diameter of the fine particles is φp, and the average diameter of the contact portion of the liquid absorbing member with the liquid on the medium is φa,
φp ≦ φa / 200
The inkjet recording method according to claim 4, wherein: The liquid absorbing member is a porous body,
When the average particle diameter of the fine particles is φp,
φp ≦ 80nm
The inkjet recording method according to claim 4, wherein: The liquid absorbing member is a porous body, and when the average particle diameter of the fine particles is φp,
φp ≤ 40nm
The inkjet recording method according to claim 7, wherein: The liquid absorbing member is a porous body,
When the average particle diameter of the fine particles is φp, and the average diameter of the contact portion with the solvent of the absorber is φa,
φp ≧ φa / 5000
The ink jet recording method according to claim 4, wherein: When the surface tension of the hydrophilization promoting solution is γ _H , the viscosity is η _H , the surface tension of the solvent component of the ink after reaction is γ _I , and the viscosity is η _I ,
γ _H / η _H <γ _I / η _I
The inkjet recording method according to claim 3, wherein: A lyophilic determination step of determining the lyophilicity of the surface of the liquid absorbing member;
11. The ink jet recording method according to claim 1, wherein when the lyophilic process is determined to be necessary, the re-lyophilic process is performed. 11.   12. The ink jet recording method according to claim 11, wherein the lyophilic determination step includes a step of dropping a predetermined amount of liquid onto the liquid absorbing member and measuring the absorption time.   The lyophilic determination step is a method of determining the lyophilicity of the liquid absorbing member based on the amount of solvent adhering to the medium before and after the solvent absorption step. Inkjet recording method. The medium is a recording medium;
14. The ink jet recording method according to claim 1, wherein in the ink application step, the ink ejected from the recording head is directly landed on the recording medium. The medium is an intermediate transfer member;
14. The ink jet recording method according to claim 1, further comprising a transfer step of transferring the color material of the ink adhered on the intermediate transfer member to a recording medium. A recording head that discharges ink containing a coloring material toward a medium;
A liquid-absorbing member that has a lyophilic surface in contact with the liquid on the medium containing the ink applied to the medium by the recording head, and that absorbs a solvent component in the ink from the medium;
Re-lyophilic treatment means for re-lyophilizing the lyophilic surface of the liquid-absorbing member, and recovering the lyophilic ability of the liquid-absorbing member;
An ink jet recording apparatus comprising: A treatment liquid applying means for applying a treatment liquid that reacts with the ink to agglomerate the color material in the ink to the medium;
The ink jet recording apparatus according to claim 16, wherein the liquid absorbing member is in contact with the liquid on the medium containing the processing liquid applied to the medium by the processing liquid applying unit.   18. The ink jet recording apparatus according to claim 16, wherein the re-lyophilic processing means applies a lyophilic promoting solution to the liquid absorbing member. Lyophilic determination means for determining lyophilicity of the surface of the liquid absorbing member;
Control means for performing control to execute re-lyophilic processing by the re-lyophilic processing means when it is determined by the lyophilic determination means that lyophilic processing is necessary;
The inkjet recording apparatus according to claim 16, further comprising: The lyophilic determination means includes
Measuring liquid applying means for applying a certain amount of liquid to the liquid absorbing member;
The ink jet recording apparatus according to claim 19, further comprising: a measuring unit that measures an absorption time of the liquid applied to the liquid absorbing member by the measuring liquid applying unit. The lyophilic determination means includes
Based on the difference between the amount of solvent adhering to the medium before absorbing the solvent by the liquid absorbing member and the amount of solvent adhering to the medium after absorbing the solvent by the liquid absorbing member, the parent of the liquid absorbing member 20. The ink jet recording apparatus according to claim 19, wherein the ink jet recording apparatus is for determining liquidity. The medium is a recording medium;
The dot according to any one of claims 16 to 21, wherein the ink ejected from the recording head is directly landed on the recording medium to record dots of the color material on the recording medium. Inkjet recording apparatus. An intermediate transfer member as the medium;
Transfer means for transferring the color material of the ink deposited on the intermediate transfer member to a recording medium;
The inkjet recording apparatus according to any one of claims 16 to 21, further comprising:

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