JP2007021891A - Image recording method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure that a successful image can be formed by arranging the positive contact of ink with a treatment liquid on an intermediate transfer medium while making a coloring material in the ink insoluble or reducing the treatment liquid amount to be flocculated, in recording an image by an intermediate transfer process. <P>SOLUTION: It is ensured that the probability of the ink coming into contact with the treatment liquid is high, even in case the given positions of the ink and/or the treatment liquid are deviated, by forming at least two dots of the treatment liquid within the range of ink dot formation. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image recording method and apparatus for forming an ink image on an intermediate transfer member using an ink jet recording system, and recording the ink image by transferring the ink image to a recording medium.

  Currently, as a recording method of an image recording apparatus that records and outputs an image created by a computer, a printed matter, an image received by a facsimile device, etc. according to a user's request, an ink jet recording method, an electrophotographic method, a thermal head method, The dot impact method is used.

  Among these methods, the inkjet recording method is a low-noise printing method in which characters and images are printed by directly ejecting ink onto a recording medium in accordance with an image signal. Since this method does not require a complicated device, the running cost is low, the device is easy to miniaturize and colorize, and from the card size to the large poster, etc. And has various advantages such as having a degree of freedom. Also in terms of image quality, in recent years, it has become possible to output a high-quality image equivalent to a silver salt color photograph. Since the recording apparatus using the ink jet system has the advantages as described above, it is not limited to a printer as an output device connected to a personal computer, but as an output device of an OA device such as a facsimile machine or a copying machine. It is used. Furthermore, in the industrial production field, various applications such as various card printing, package printing, and large-sized poster creation are made.

  As a recent trend, taking advantage of the above-described advantages of the ink jet recording method, there is an increasing demand to output an image with high quality by the ink jet recording method regardless of the type of the recording medium in various fields. In order to meet such a demand, it is strongly desirable to suppress factors that cause a reduction in image quality on a recording medium and a decrease in the texture of printed matter. Specifically, it is necessary to suppress, for example, phenomena such as feathering, beading, and bleeding, and the wavy phenomenon (cockling) of the recording medium that occurs when water-based ink permeates the recording medium. These phenomena are caused by high-definition and high-speed ink jet recording, and a large amount of ink is applied per unit area of the recording medium. Various recording materials are also used as the recording medium. Under such circumstances, it must be more effectively suppressed.

  Therefore, an ink is applied on the intermediate transfer member by an ink jet recording method to form an ink image, and the ink image is further thickened by drying the ink, or the solvent is removed from the ink image to concentrate the ink, and then In addition, a method called a transfer method for transferring an ink image from an intermediate transfer member onto a recording medium has been proposed.

  This recording method using a transfer method does not perform recording by directly applying ink from a recording head to a recording medium. Accordingly, since the moisture in the ink is quickly penetrated and fixed to the recording medium, the phenomenon such as feathering, beading, and bleeding is not suppressed, so that the types of recording media that can be used can be expanded. That is, even when a recording medium with poor ink permeability is used, this is an effective solution to the problem of image quality degradation. In addition, the amount of liquid penetrating the recording medium side can be reduced by performing a process of removing almost all liquid components of the ink forming the ink image before transferring the ink image formed on the intermediate transfer member to the recording medium. Few. Accordingly, since cockling is difficult to occur, there is an advantage that the texture of the recording medium such as “strain” and touch is not impaired.

  Furthermore, the use of an intermediate transfer member in ink jet recording has a configuration in which a recording head having nozzles for ejecting ink is disposed at a position distant from the recording medium. There is an advantage that dust such as is difficult to adhere to the nozzle. That is, problems such as clogging caused by paper dust or the like adhering to the nozzle can be prevented.

  However, as a premise for recording an image of good quality, the phenomenon that causes the deterioration of the image quality must be suppressed even on the intermediate transfer member. Therefore, prior to the formation of the ink image, a method has been proposed in which a treatment liquid that reacts with the ink to cause thickening of the ink or aggregation / insolubilization of the coloring material is applied to the intermediate transfer member (for example, Patent Documents). 1).

  Here, when a large amount of processing liquid is applied, that is, a thickness that is equal to or larger than the diameter of one ink dot formed on the intermediate transfer member, the force that the ink image adheres to the intermediate transfer member is reduced and the image is disturbed. Occurs. For this reason, it is an important issue to apply a necessary and sufficient amount of the processing liquid onto the intermediate transfer member without causing thickening or a reduction in the aggregation effect on the intermediate transfer member.

  As a method of applying the processing liquid onto the intermediate transfer member, the processing liquid is discharged using a recording head equivalent to the recording head that applies the processing liquid using a roller, a blade, or a spray, or the recording head that discharges ink. Things. By using a roller, a blade, a spray, or the like, it is possible to apply the treatment liquid thinly on the intermediate transfer member and apply it to the entire surface. However, on the other hand, the method of applying by the recording head is different from those by coating, and the treatment liquid can be selectively applied according to the image, so that an ink image is formed on the intermediate transfer member according to the image data. It is more preferable because the thickness of the processing liquid can be reduced in the portion and the consumption of the processing liquid can be reduced.

  Patent Document 2 discloses a treatment liquid (ink containing color material) having an action of aggregating color material components in ink by using a recording head and contacting ink (ink containing color material). A method of applying before ink image formation is disclosed. For the treatment liquid, it is described that the application amount is made smaller than the ink amount, or that the pixels are thinned out.

US Pat. No. 5,958,169 JP 2002-370441 A

  Here, when the processing liquid is selectively applied by the recording head, the processing liquid and the ink must surely meet when the ink is applied onto the intermediate transfer member.

  On the other hand, in an image recording method using an intermediate transfer body, the intermediate transfer body must have a surface having releasability when transferring ink to a recording medium, and this requires a low surface energy. However, the processing liquid is difficult to spread on the intermediate transfer member. By adding a surfactant to the treatment liquid, it is possible to reduce the surface tension and promote wetting and spreading. However, in consideration of leakage of the processing liquid from the recording head and ejection characteristics, the amount of the surfactant added is limited, and thus the amount of wetting and spreading of the processing liquid is also limited.

  Then, as in Patent Document 2, when the amount of processing liquid is reduced on the intermediate transfer member or the recording position is thinned out, the processing liquid repels on the intermediate transfer member and the landing position of the processing liquid / ink droplet from the recording head. There is a possibility that a portion where the processing liquid and the ink do not meet each other is generated due to the shift of the gap. For example, when a change in the ejection direction due to aging of the recording head, dirt on the head, fluctuation, etc. occurs, the landing position shifts on the intermediate transfer member, and a portion where the processing liquid and the ink do not meet is generated. This part becomes an unreacted region. Then, the image of this portion is disturbed at the time of transfer, and “blurring” or “streaks” of the image due to deformation of the dots after transfer may occur, thereby causing image deterioration.

  The present invention has been made in view of such a problem, and ensures that the ink and the treatment liquid meet while reducing the amount of the treatment liquid. That is, the treatment liquid is attached to the optimum position in an appropriate amount. The purpose of the present invention is to make it possible to maximize the function of the processing liquid and to form a good image.

  For this purpose, the present invention provides an image recording method in which recording is performed by ejecting ink onto an intermediate transfer member to form an image composed of ink dots, and transferring the formed image onto a recording medium. In the formation range, at least two dots of the treatment liquid that insolubilize or aggregate the color material in the ink are formed.

The present invention also provides an image for recording by forming an image composed of ink dots on an intermediate transfer member using an ink recording head for ejecting ink, and transferring the formed image to a recording medium. In the recording device,
A processing liquid applying unit that uses a processing liquid recording head for discharging a processing liquid that insolubilizes or aggregates the coloring material in the ink and forms at least two dots of the processing liquid with respect to the ink dot forming range. It is characterized by comprising.

  According to the present invention, when performing intermediate transfer type image recording, the function of the processing liquid is maximized by ensuring that the ink and the processing liquid meet on the intermediate transfer body while reducing the amount of the processing liquid. Therefore, a good image can be formed.

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

1. 1 is a schematic cross-sectional view showing a schematic configuration of a main part of an image recording apparatus according to an embodiment of the present invention.

  In FIG. 1, a transfer drum 1 is an intermediate transfer member having an ink releasable surface layer. The transfer drum 1 is supported on a shaft 1a and can be driven to rotate in the direction of arrow A about the shaft 1a by a drum driving device (not shown). At a position facing the circumference of the transfer drum 1, the processing liquid application unit 2, the ink application unit 3, the ink image processing unit 4, the recording medium separation unit 6, and the transfer are sequentially arranged from the upstream side in the A direction toward the downstream side. A part 5 and a cleaning part 7 are arranged.

  Further, the image recording apparatus is provided with a paper feeding / conveying unit 9 for conveying the recording medium 8 from a recording medium storage unit (paper feeding cassette) (not shown) to the recording medium separating unit 6. Further, the image recording apparatus fixes the ink image on the recording medium 8 after the ink image formed on the transfer drum 1 that is an intermediate transfer member is transferred to the recording medium 8, and also places it on a paper discharge tray (not shown). A paper discharge fixing unit 10 for discharging the recording medium 8 is disposed.

  FIG. 2 is a block diagram showing a schematic configuration example of the control unit system of the image recording apparatus.

  In the image recording apparatus denoted as a whole by reference numeral 100, the CPU 101 executes control processing of the operation of the recording apparatus, data processing, and the like. The memory 103 is a storage unit having a ROM (not shown) that stores programs such as those processing procedures and a RAM (not shown) that is used as a work area for executing these processes. The I / F 105 is an interface for exchanging information such as data and commands between the inkjet recording apparatus and the image supply apparatus 110 that is a source of image data such as a host computer.

  In addition to the above parts, the transfer drum 1, the treatment liquid application unit 2, the ink application unit 3, the ink image processing unit 4, the transfer unit 5, the recording medium separation unit 6, the cleaning unit 7, the paper feed conveyance unit 9, and the paper discharge conveyance. The fixing unit 10 is connected to the bus line 120. Therefore, the CPU 101 can execute necessary control while appropriately transmitting and receiving signals to and from each unit via the bus line 120. In addition, a state detection sensor is provided in each part to be controlled, and the detection signal can be transmitted to the CPU 101 via the bus line 120.

2. 2. Details of Each Part 2.1 Intermediate Transfer Body As shown in FIG. 1, a transfer drum 1 as an intermediate transfer body is formed by laminating a surface layer 13 made of silicone rubber around a support body 12 made of aluminum.

  The material used as the support 12 is not particularly limited to aluminum. In addition to the rigidity and dimensional accuracy that can withstand the pressure applied during transfer, as long as it satisfies the characteristics required for reducing rotational inertia and improving control responsiveness, for example, nickel, iron phosphate It is also possible to use a metal such as acetal, a thermosetting resin excellent in strength such as acetal, or a ceramic or the like.

  Also, the ink releasable surface layer 13 is not limited to silicone rubber. Any layer may be used as long as it has preferable releasability and elastic properties and has an excellent transfer rate when transferring an ink image to a recording medium. As described above, releasability refers to a state in which an ink image can be removed without adhering to the surface of the intermediate transfer member. The higher the releasability, the greater the load on cleaning and the transfer rate of ink. It is advantageous.

  Note that a heater or other temperature adjusting means can be added to the transfer drum 1.

2.2 Processing liquid application unit 2.2.1 Configuration The processing liquid application unit 2 illustrated in FIG. 1 includes a plurality of nozzles that can control the discharge of the processing liquid in accordance with an image signal sent from the control unit. By using the recording head 14, the treatment liquid is applied to the intermediate transfer member. In the image recording apparatus according to the present embodiment, a heating element (discharge heater) that is an electrothermal conversion element that generates thermal energy used to discharge the processing liquid in response to energization is used as the recording head 14 for the processing liquid. A nozzle having an array of nozzles is used. The recording head 14 is a line type in which such nozzles are arranged in the axial direction of the transfer drum 1 (direction perpendicular to the paper surface of FIG. 1). The recording head 14 receives supply of processing liquid from a processing liquid tank (not shown). The heating element of the recording head 14 generates heat in response to an image signal for applying the processing liquid to increase the temperature of the processing liquid and generate bubbles. Then, when the generated bubble expands, the processing liquid is discharged from the nozzles of the recording head 14.

  The configuration of the recording head 14 is not limited to the line type. A so-called serial type recording head in which a plurality of nozzle rows are arranged in a predetermined range in the circumferential direction or the axial direction of the transfer drum 1 is used, and images are sequentially formed on the transfer drum 1 while scanning the recording head in the axial direction. You can do it. When such a recording head is used, rotation of the transfer drum 1 is intermittently performed, and rotation driving in units of the nozzle arrangement range or usage range in the circumferential direction of the head, and drive stop at the time of serial scanning of the recording head, Are repeated alternately.

  Further, the ink jet recording head is not limited to the form using the heat generating element, and any discharge system can be used as long as it can discharge the treatment liquid from the nozzle of the recording head, such as a piezoelectric element.

  The same applies to the recording head for ink application described later.

2.2.2 Treatment liquid Here, the treatment liquid according to the present embodiment will be described in detail. The treatment liquid is a chemical reaction or physical adsorption to a colorant or resin that is a part of the composition constituting the colored ink, thereby reducing the fluidity of the entire ink, that is, the viscosity. Say something that causes a rise. Further, it also refers to a material that causes a local decrease in fluidity, that is, an increase in viscosity by aggregating the solid content of the composition constituting the ink.

  Specifically, the treatment liquid contains at least a cationic substance. The cationic substance is not limited to a polymer or a low molecule, and may be any substance that insolubilizes the ink and causes the ink fluidity to decrease or agglomerate, and preferably to rapidly decrease the fluidity. Consists of a metal salt. Specifically, it plays the role of reducing the fluidity of the ink on the intermediate transfer member by contact with the ink and holding the ink landed on the intermediate transfer member at the landing position as much as possible. As a result, even when ink droplets come into contact with each other on the intermediate transfer member, it is possible to suppress occurrence of beading and bleeding and form a good image.

As the treatment liquid, a material that agglomerates ink by contact with ink is suitable, and for example, a liquid containing a metal salt is suitable. The most suitable metal salt constituting the treatment liquid is a polyvalent metal salt. The polyvalent metal salt is composed of a divalent or higher polyvalent metal ion and an anion that binds to the polyvalent metal ion. Specific examples of the polyvalent metal ions include divalent metal ions such as Ca ²⁺ , Cu ²⁺ , Ni ²⁺ , Mg ²⁺ and Zn ²⁺ , and trivalent metal ions such as Fe ³⁺ and Al ^3+. Is mentioned. Further, examples of the anion that binds to these include anions such as Cl ⁻ , NO ³⁻ , SO ₄ ²⁻ , I ⁻ , Br ⁻ , ClO ³⁻ , and RCOO ⁻ (where R is an alkyl group). Moreover, a water-soluble organic solvent can be contained in a processing liquid with metal salts, such as the above-mentioned polyvalent metal salt. Although there is no restriction | limiting in particular about content in the processing liquid of a water-soluble organic solvent, It is 5-60 mass% of the total mass of a processing liquid, Preferably it is the range of 5-40 mass%.

  Furthermore, the treatment liquid may contain, for example, a water-soluble resin, a water-soluble crosslinking agent, an acidic solution, or the like as an agglomeration aid. Any material that can be suitably used may be any material that can coexist with the polyvalent metal salt. As the water-soluble resin, polyvinyl alcohol, polyvinyl pyrrolidone, or the like is used. Since these aggregating auxiliary materials have a relatively large molecular weight, the internal aggregating force of the ink agglomerated image formed by the combined use with the polyvalent metal salt can be increased. As a result, the transfer efficiency of the ink aggregated image to the recording medium 8 and the scratch resistance can be improved.

Furthermore, it is preferable to use a surfactant in the processing liquid for the purpose of stably discharging the recording head 14 of the processing liquid onto the transfer drum 1.
As the surfactant, various surfactants such as a water-soluble anionic surfactant, cationic surfactant, nonionic surfactant, and amphoteric surfactant can be used.

  The addition amount of the surfactant is preferably about 0.05 to 5% by mass, more preferably about 0.1 to 1% by mass with respect to the treatment liquid.

  In addition to these, additives such as a viscosity adjusting agent, a pH adjusting agent, a preservative, and an antioxidant may be appropriately added to the treatment liquid as necessary. Further, the treatment liquid used in the present embodiment is more preferably colorless, but it may be light in a range that does not change the color tone of each color ink when mixed with ink on a recording medium. Furthermore, it is preferable that the treatment liquid made of the above-described forming material has its physical properties adjusted so that the viscosity at around 25 ° C. is in the range of 1 to 30 cP (mPa · s).

  In the present embodiment, the treatment liquid includes a metal salt. However, the treatment liquid may include a metal salt as long as the fluidity of the ink is reduced.

A treatment liquid for aggregating the pigment as the colorant in the ink can be obtained as follows as an example. That is, after mixing and dissolving the following components, pressure filtration with a membrane filter (trade name: Fluoropore filter, manufactured by Sumitomo Electric) having a pore size of 0.22 μm, and then adjusting the pH to 5.8 with KOH. A colorless treatment liquid Al can be obtained.
(Component of A1)
・ Calcium chloride dihydrate 10 parts ・ Diethylene glycol 20 parts ・ Acetylenol EH (manufactured by Kawaken Fine Chemicals) 0.5 part
・ Water balance

2.3 Ink Applying Unit 2.3.1 Configuration The ink applying unit 3 receives an image signal sent from the control unit onto the transfer drum 1 to which the processing liquid is applied by the processing liquid applying unit 2 as described above. Accordingly, an ink image is formed by applying ink by the recording head 15 having a plurality of nozzles capable of controlling the ejection of ink containing at least a colorant.

  In FIG. 1, the ink applying unit 3 is disposed on the downstream side of the treatment liquid applying unit 2 on the transfer drum 1, and includes recording heads 15a, 15b, 15c and 15d. Hereinafter, the recording heads 15a, 15b, 15c, and 15d may be collectively referred to as the recording head 15. These recording heads basically have the same form as the processing liquid recording head 14 described above. Of course, it is possible to adopt a modification similar to that described above with respect to the configuration and the ejection method.

  The recording heads 15, 15 b, 15 c and 15 d are arranged at regular intervals in the circumferential direction of the transfer drum 1. Each is configured to apply a different color ink to form a color image. In the configuration of FIG. 1, the recording heads 15a, 15b, 15c and 15d respectively apply black (K), cyan (C), magenta (M) and yellow (Y) inks. Yes. However, the number of ink jet recording heads constituting the ink applying unit 3 in the present embodiment, the color order of the ink ejected to the transfer drum 1, and the hue of the ink used are not limited to the above.

  Note that the ink image formed on the transfer drum 1 must be a mirror image of an image to be finally formed on the recording medium 8 in consideration of reversal at the time of transfer. Naturally, the image signal supplied to the recording head 15 must be an image signal corresponding to a mirror image. Therefore, in the control system of FIG. 2, mirror inversion processing (inversion data is obtained) for the image signal sent from the image supply device 110 (that is, the image signal corresponding to the image finally formed on the recording medium 8). Processing) to obtain an image signal corresponding to the mirror image and supply it to the recording head.

2.3.2 Ink The ink used in the ink application unit 3 is not particularly limited, and any general ink jet ink can be used. In particular, the pigment ink is less likely to bleed with respect to the recording medium as compared with the dye ink, and is excellent in water resistance and light resistance. Therefore, a pigment containing at least a pigment as an ink colorant that can be suitably used in this embodiment. It is preferable to use ink.

  However, the ink is not limited to pigment ink using a pigment as a colorant. A dye ink may be used, or a mixed ink obtained by adding a dye to a pigment, for example, a mixed ink containing a conventionally known dye for changing the hue may be used. In addition, when a treatment liquid containing a metal salt is used, an ink and / or treatment liquid to which a water-soluble resin, a crosslinking agent or the like is added in order to enhance the internal cohesion of the ink aggregation image is used. It may be used.

  The following can be mentioned as an example of each color pigment ink which mixes with colorless liquid A1 which is the processing liquid mentioned above, and causes aggregation. That is, as described below, black, cyan, magenta, and yellow color inks K, C, M, and Y each containing a pigment and an anionic compound can be obtained.

Black ink K
Anionic polymer P-1 (styrene-methacrylic acid-ethyl acrylate, acid value 400, weight average molecular weight 6,000, 20% solid content aqueous solution, neutralizing agent: potassium hydroxide) was used as a dispersant. The materials shown were charged into a batch type vertical sand mill (manufactured by Imex), filled with 1 mm diameter glass beads as media, and dispersed for 3 hours while cooling with water. The viscosity after dispersion was 9 cps and the pH was 10.0. This dispersion was centrifuged to remove coarse particles, and a carbon black dispersion having a weight average particle diameter of 100 nm was produced.

(Composition of carbon black dispersion)
-P-1 aqueous solution (solid content 20%) 40 parts-Carbon black Mogul L (manufactured by Cablack) 24 parts-Glycerin 15 parts-Ethylene glycol monobutyl ether 0.5 part-Isopropyl alcohol 3 parts-Water 135 parts The dispersion obtained above was sufficiently diffused to obtain an inkjet black ink K containing a pigment. The final preparation had a solid content of about 10%.

Cyan ink C
The anionic polymer P-1 used in the production of the black ink K was used as a dispersant, and the same dispersion treatment as in the case of the above-described carbon black dispersion was performed using the materials shown below. A cyan dispersion having a diameter of 120 nm was prepared.
(Composition of cyan dispersion)
-P-1 aqueous solution (solid content 20%) 30 parts-C.I. I. Pigment Blue 15: 3 24 parts (Fast Genble-FGF, manufactured by Dainippon Ink & Chemicals)
・ Glycerin 15 parts ・ Diethylene glycol monobutyl ether 0.5 part ・ Isopropyl alcohol 3 parts ・ Water 135 parts The cyan dispersion obtained above was sufficiently stirred to obtain a cyan ink C for inkjet containing a pigment. It was. The final preparation had a solid content of about 9.6%.

Magenta ink M
The anionic polymer P-1 used in the production of the black ink K was used as a dispersant, and the same dispersion treatment as in the case of the above-described carbon black dispersion was performed using the materials shown below. A magenta color dispersion having a diameter of 115 nm was prepared.

(Composition of magenta color dispersion)
-P-1 aqueous solution (solid content 20%) 20 parts-C.I. I. Pigment Red 122 (Dainippon Ink Chemical Co., Ltd.) 24 parts ・ Glycerin 15 parts ・ Isopropyl alcohol 3 parts ・ Water 135 parts The magenta color dispersion obtained above is sufficiently diffused to contain magenta for inkjet containing a pigment. Ink M was obtained. The final preparation had a solid content of about 9.2%.

Yellow ink Y
Anionic polymer P-2 (styrene-acrylic acid-methyl methacrylate, acid value 280, weight average molecular weight 11,000, aqueous solution with a solid content of 20%, neutralizer: diethanolamine) is used as a dispersant, and is shown below. Using the materials, a dispersion treatment was performed in the same manner as in the production of the black ink K2, and a yellow color dispersion having a weight average particle diameter of 103 nm was produced.

(Composition of yellow dispersion)
-P-2 aqueous solution (solid content 20%) 35 parts-C.I. I. Pigment Yellow 180 24 parts (Nova Palm Yellow PH-G, manufactured by Hoechst)
・ Triethylene glycol 10 parts ・ Diethylene glycol 10 parts ・ Ethylene glycol monobutyl ether 1.0 part ・ Isopropyl alcohol 0.5 part ・ Water 135 part The yellow dispersion obtained above was sufficiently diffused to contain a pigment. A yellow ink Y for inkjet was obtained. The final preparation had a solid content of about 10%.

2.4 Ink Image Processing Unit Next, in FIG. 1, the ink image processing unit 4 includes an air knife 16 and a solvent tray 17. The ink image processing unit 4 removes the solvent component including water from the ink image formed by the ink application unit 3 so that the ink can be transferred under optimum ink adhesion conditions when transferred to the recording medium 8. The image is processed.

  The ink image processing unit 5 includes an air knife 16 for sending warm air heated by a heater (not shown) and a solvent tray 17 in order to evaporate or separate and remove the solvent in the ink, mainly the water in the ink. And are provided. In other words, the ink image processing unit 5 adjusts the amount of air blown from the air knife or the amount of heat related to the temperature of the air in consideration of the difference in the permeability of the ink image that is an ink aggregated image to the recording medium 8. Thus, it is provided for the purpose of controlling the transfer characteristic of the ink image to the recording medium 8.

  In this embodiment, the air knife 16 is used to accelerate the drying of the ink image. However, an infrared heater or the like that can adjust the temperature and control the transfer characteristics of the ink image can also be used. . Also, as long as the solvent containing water in the ink can be removed in a controllable manner, a known means for absorbing the solvent containing water or a means using a squeegee blade roller for squeezing the solvent containing water can be used. It is.

2.5 Transfer unit 5, paper feed conveyance unit 6 and recording medium separation unit 6
In FIG. 1, the transfer unit 5 includes a transfer roller 18. In addition, the sheet feeding / conveying unit 6 includes conveyance rollers 19a and 19b and conveyance guides 20a and 20b. In the transfer unit 5, the recording medium 8 transported through the guide portion between the transport guides 20 a and 20 b as the transport rollers 19 a and 19 b of the paper feed transport unit 6 rotates is pressed against the transfer drum 1 by the transfer roller 18. Thus, the ink image on the transfer drum 1 is transferred to the surface of the recording medium.

  The transfer roller 18 is disposed so as to pass through the recording medium 8 at the nip portion with the transfer drum 1 and can be formed by a rubber roller, a metal roller, or the like. By adding a pressure control device (not shown) to the transfer unit 5, it is possible to control the pressure on the transfer drum 1 and its release.

  In FIG. 1, the transport rollers 19a and 19b rotate in the arrow B direction, and the transfer roller 18 rotates in the arrow C direction. The transfer roller 18 can rotate following the transfer drum 1 via the recording medium 8 in a pressed state against the transfer drum 1. In addition to such driven rotation, the rotation may be controlled by an independent transfer roller driving means (not shown). In this embodiment, the transfer roller 18 is configured to press the transfer drum 1 with a linear load of 0.6 kg / cm through the recording medium 8 during transfer. However, the present invention is not limited to this.

  On the other hand, in FIG. 1, the recording medium separating unit 6 includes a separating claw 21. In the recording medium separation unit 6, the separation claw 21 operates according to the conveyance timing of the recording medium 8. When the transfer is completed, the separation claw 21 is driven by a driving device (not shown) to separate the recording medium 9 from the transfer drum 1 and discharge the recording medium 8 via a guide portion between the conveyance guides 22a and 22b. Guide to the conveyance fixing unit 11.

2.6 Paper Discharge Transport Fixing Unit In FIG. 1, the paper discharge transport fixing unit 10 includes transport guides 22a and 22b and transport fixing rollers 23a and 23b. In the paper discharge conveyance fixing unit 10, the recording medium 8 onto which the ink image guided between the conveyance guides 22a and 22b has been transferred is heated by the conveyance fixing rollers 23a and 23b incorporating the infrared heaters to fix the transferred image. . Further, the recording medium 8 is sent to a paper discharge tray (not shown) by the rotation of the rollers, and the recording on the recording medium is finished. A known fixing roller can be used as the transport fixing rollers 23a and 23b, and the temperature is preferably about 30 to 200 ° C. The roller material can be metal, silicone rubber, or the like. In order to improve the peelability of the recording medium 8, silicone oil or the like may be applied to the roller surface.

2.7 Cleaning Unit In FIG. 1, the cleaning unit 7 includes a cleaning liquid holding member 25, a cleaning liquid supply roller 26a, and a cleaning roller 26b. The cleaning liquid holding member 25 stores and holds the cleaning liquid 24. The cleaning roller 26b rotates while being in contact with the transfer drum 1, thereby applying the cleaning liquid 24 and removing dust and the like on the transfer drum 1. The cleaning liquid supply roller 26a is in the middle of these and supplies the cleaning liquid 24 from the cleaning liquid holding member 25 to the cleaning roller 26b.

  In the figure, the cleaning roller 26b may be driven and rotated by the transfer drum 1, or may be driven and controlled by a driving means (not shown). The cleaning liquid supply roller 26a may be driven and rotated by the cleaning roller 26b, or may be driven and controlled by a driving unit (not shown). In any case, when the cleaning liquid supply roller 26a and the cleaning roller 26b rotate, the cleaning liquid 24 is applied onto the transfer drum 1 through these rollers, and the transfer drum 1 is cleaned.

  The configuration of the cleaning unit 7 is not limited to that shown in the drawings as long as the surface of the transfer drum 1 can be appropriately cleaned. Further, the type of the cleaning liquid 24 is not particularly limited, and for example, an aqueous solution containing a surfactant, a water-soluble organic solvent, or the like used in the treatment liquid can be preferably used.

  Further, by adding a pressing control device (not shown) to the cleaning roller 26b as well as the transfer unit 5, it is possible to control the pressing to the transfer drum 1 and the release thereof.

3. Recording Procedure A series of recording operations of the image recording apparatus will be described.

  FIG. 3 shows a recording processing procedure of the image recording apparatus according to the embodiment shown in FIGS.

  When the power of the image recording apparatus is turned on and the start of recording is instructed, a start process is first executed (step S1). The start process includes a process of turning on and adjusting the heaters for the interior of the transfer drum 1, the air knife 16, and the conveyance fixing rollers 23a and 23b in addition to the rotation driving of the transfer drum 1, and setting each part to a predetermined temperature. be able to. Further, the position of each part of the recording medium conveyance system can be set as necessary. Furthermore, when it is desirable to clean the surface of the transfer drum 1 prior to an image forming operation described later, the cleaning roller 26b is pressed against the transfer drum 1 so that the cleaning liquid is applied and cleaned. May be.

  When an image signal is received from the image supply device 110 such as a computer, the generation of recording data for defining the ejection operation by the ink recording head 15 and the treatment liquid recording head 14 in accordance with the image signal and expansion into the memory area are performed. Perform (step S3).

  Specifically, for example, a binary image signal corresponding to each ink color (K, C, M, and Y) used in the present embodiment and corresponding to the presence or absence of ejection is sent from the image supply device 110. If it comes, the mirror inversion process is performed as it is, and it is developed as recording data in the memory area for each color recording head. If a multi-valued image signal of three or more values is sent from the image supply device 110, the CPU 101 converts it into a binary image signal by executing a predetermined binarization processing program and then mirrors it. Perform reversal and expand. For the processing liquid recording head, a logical sum of each color recording data is calculated corresponding to the recording position, and a plurality of dots of processing liquid are provided for one dot of data at each recording position subjected to the OR operation. The recording data for the processing liquid is generated and developed as given.

  A specific example for applying a plurality of dots of processing liquid to one dot of data at the recording position will be described later. Although the recording data of the processing liquid recording head is generated corresponding to the logical sum of the recording data of each color ink, the present invention is not limited to this. For example, instead of using the logical sum data of each color ink as the processing liquid data as it is, the processing liquid data is appropriately set within a range in which the intended purpose of the present invention of ensuring that the ink and the processing liquid meet each other can be achieved. Thinning may be performed.

  Next, the processing liquid recording head 14 and the ink recording heads 15 (15a, 15b, 15c, and 15d) are driven on the rotationally driven transfer drum 1 based on the developed recording data. The operation is performed to form an ink image (mirror inverted image of the image finally recorded on the recording medium 8) (step S7).

  At this time, since the ink applied onto the transfer drum 1 by the ink recording head 15 and the processing liquid previously applied by the processing liquid recording head 14 cause agglomeration and the like, the transfer drum 1 is rapidly generated. An aggregated ink image is formed on the top. As a result, not only can the ink image be efficiently formed on the transfer drum 1 as described above, but also when a color ink image is formed on the transfer drum 1 using inks having different densities or a plurality of color inks. Since the color ink image on the transfer drum 1 is formed of agglomerated ink, phenomena such as beading and bleeding do not occur. Moreover, even if this color ink image is transferred onto a recording medium, an effect that a high-quality color image without beading or bleeding can be formed on the recording medium can be obtained. In particular, this effect becomes more prominent when high-speed recording is performed or when multiple colors of ink are applied in forming a color image. And especially in this invention, use of a processing liquid is implement | achieved efficiently and effectively by determining the aspect of application | coating of a processing liquid appropriately.

  Subsequently, the ink image is subjected to evaporation and drying of a solvent containing moisture in the ink processing unit 4, and the ink conditions become more optimal for the subsequent transfer.

  On the other hand, the recording medium is conveyed so that the position with the formed ink image is aligned (step S9). That is, recording is performed on the transfer unit 5 by the transport rollers 19a and 19b so that the leading end position of the ink image formed on the transfer drum 1 as described above and the recording medium 8 overlap at the nip portion that is the transfer position. The medium 8 is conveyed. In the transfer unit 5, when it is detected by a sensor (not shown) that the leading end of the recording medium 8 has reached the nip portion between the transfer drum 1 and the transfer roller 18, the transfer roller 18 is driven and transferred via the recording medium 8. Pressed against the drum 1. Here, a predetermined transfer pressure is generated by the pressure control device, and the ink image on the transfer drum 1 is transferred to the recording medium 8.

  Then, at the same time that a sensor (not shown) detects that the leading end of the recording medium 8 has been ejected from the transfer unit 5, the separation claw 21 is driven and inserted between the transfer drum 1 and the recording medium 8, and recording is performed. The medium 8 is separated from the transfer drum 1. The recording medium 8 separated from the transfer drum 1 passes through the conveyance guides 22a and 22b, is heated by the conveyance fixing rollers 23a and 23b, is subjected to fixing processing, and is then guided to the paper discharge tray.

  The above-described series of ink image formation, recording medium conveyance, and transfer is continued, and when recording on one recording medium 8 is completed, an end process is executed (step S11). Specifically, a process for separating the transfer roller 18 and the separation claw 21 from the transfer drum 1 is performed. Further, the cleaning roller 26b is brought into contact with the transfer drum 1, the surface of the transfer drum 1 is cleaned while applying the cleaning liquid 24, and the cleaning roller 24b is separated from the transfer drum 1 when the transfer drum 1 rotates once. Can be executed. Further, when recording is continued on the subsequent recording medium, the above-described series of ink image formation, recording medium conveyance and transfer operations according to the image signal are repeated, while the recording operation is terminated and the power is turned off. The heater driving and the rotation driving of the transfer drum 1 can be turned off.

4). Specific Example Next, a specific example for appropriately applying a plurality of dots of processing liquid to one dot of data at the recording position will be described.

4.1 First Example In FIG. 4, alphabetic characters “a” to “k” represent recording positions in the transfer drum rotation direction A of the above embodiment, and numerals “0” to “6” represent transfer drum axial directions. The recording position in (nozzle row direction) is shown.

  In this embodiment, with respect to the transfer drum rotation direction, the ink recording head 15 is driven so that the image formation density is 1200 dpi (dots / inch; reference value), while the processing liquid application density is 2400 dpi. The liquid recording head is driven. Further, the ink recording head 15 was used with an ejection amount of 4 pl per nozzle, and the treatment liquid recording head 14 was used with an ejection amount of 1 pl per nozzle.

  That is, in this embodiment, the treatment liquid dots D2 are formed with a density twice as large as the transfer dots in the rotation direction of the ink dots D1 to be formed on the transfer drum 1 that is an intermediate transfer member. Specifically, assuming that there is recording data to which ink of at least one of K, C, M, and Y is applied at a certain position, the position of the recording data corresponding to each color ink is calculated by performing an OR operation on the recording data corresponding to each color ink. The logical sum data is 1. Ink dots D1 indicated by white circles in FIG. 4 indicate data positions to which such at least one color of ink is applied. The data indicating such ink dots is doubled in the drum rotation direction and used as processing liquid data, and the processing liquid recording head is driven in the transfer drum rotation direction at twice the frequency of the ink recording head. To do. As a result, the treatment liquid dot D2 is formed at the position indicated by the hatched circle.

  Therefore, two treatment liquids are applied to one dot of ink, and even if the landing positions of the ink and / or the treatment liquid are deviated, the probability that the ink and the treatment liquid meet each other increases. By this method, the treatment liquid steadily comes into contact with the ink dots, and the ink coloring material is aggregated or insolubilized, so that the ink image is fixed on the intermediate transfer member, and thus good image recording is performed. Further, since the discharge amount per nozzle of the treatment liquid recording head 15 is smaller than that of the ink recording head 15, the amount of the treatment liquid applied onto the transfer drum can be appropriately limited. It becomes possible. If the amount of the processing liquid is almost equal to that of the ink recording head 15, the intermediate transfer member is a non-absorbing body, so that the beading of the processing liquid increases and the thickness of the processing liquid is substantially locally increased. It becomes thick and a good image cannot be formed.

  In this example, the treatment liquid application density of the treatment liquid recording head is twice the treatment liquid application density of the ink recording head in the rotation direction of the transfer drum. However, the present invention is not limited to this. What is necessary is just to drive the recording head to be larger than the latter.

4.2 Second Example Also in FIG. 5, the letters “a” to “k” represent recording positions in the transfer drum rotation direction A of the above embodiment, and the numbers “0” to “6” represent the transfer drum shaft. The recording position in the direction (nozzle row direction) is shown. However, in this embodiment, each position in the A direction is 600 dpi, the ink recording head 15 has nozzles arranged at a density of 600 dpi, and the processing liquid recording head 14 has a density of 1200 dpi. A nozzle in which nozzles are arranged was used. Further, the ink recording head 15 and the treatment liquid recording head 14 have discharge amounts of 5 pl and 1 pl per nozzle, respectively.

  That is, in this embodiment, the processing liquid dot D2 is formed using the processing liquid recording head having a higher resolution than the ink recording head for the ink dot D1 to be formed on the transfer drum 1 as an intermediate transfer body. .

  In this recording method, presence / absence of recording data for forming ink dots (hereinafter referred to as “recording dot formation data”) is determined for each dot in the nozzle array direction, and the processing liquid is determined according to the determination result. To form a treatment liquid dot D2.

  That is, the presence / absence of the print dot formation data at the position in the nozzle row direction is determined for the print data corresponding to the line in the nozzle row direction in FIG. First, since the recording dot formation data exists at the coordinates (b, 2), the processing liquid is ejected to the corresponding coordinates (b, 2) and coordinates (b, 1) and (b, 3). Thus, the treatment liquid dot D2 is formed. Next, since there is no recording dot formation data from coordinates (b, 4) to (c, 0), the processing liquid is not discharged to the corresponding position. Next, since there is recorded dot formation data at the coordinates (c, 2), the processing liquid is applied to the corresponding coordinates (c, 2) and coordinates (c, 1) and (c, 3). The treatment liquid dots D2 are formed by discharging. Next, since the recording dot formation data exists at the coordinates (c, 4), the processing liquid is discharged to the corresponding coordinates (c, 4) position and coordinates (c, 3) and (c, 5). Thus, the treatment liquid dot D2 is formed.

  In this way, the treatment liquid discharge position is determined for each line. Subsequently, the presence or absence of recording dot formation data is determined for all the recording data corresponding to the determination position in the same manner, and the discharge position of the processing liquid is determined.

  D2 in FIG. 5 represents a processing liquid dot formed at the processing liquid ejection position determined in this way. As is apparent from FIG. 5, the treatment liquid dots D2 formed in advance before the formation of the ink dots D1 are positioned so that a plurality of treatment liquid dots D2 exist within the formation range of the single ink dots D1. On the other hand, the effect of insolubilizing or aggregating ink by a plurality of treatment liquid dots is exerted. As a result, the same basic effects as those of the first embodiment can be obtained.

  Further, in this embodiment, since a plurality of treatment liquid dots D2 overlap each other at the boundary portion of each ink dot D1 in the nozzle row direction, the applied amount becomes large. By preferably mixing with the ink, an effect of reducing the occurrence of uneven stripes in a direction parallel to the drum rotation direction can be obtained.

  In this example, the treatment liquid recording head has a nozzle arrangement density twice that of the ink recording head. However, the present invention is not limited to this, and the former has a nozzle arrangement density higher than the latter. Just do it.

3.3 Third Embodiment FIG. 6 is an explanatory diagram of a third embodiment for appropriately applying a plurality of dots of processing liquid to one dot of recording position data, and FIG. 7 is a third embodiment. FIG. 6 is a schematic front view seen from the discharge port direction in order to explain the configuration of the processing liquid recording head used in FIG.

  Here, as the ink recording head 15, one having nozzles arranged at a density of 600 dpi and having an ejection amount of 8 pl per nozzle was used. On the other hand, as shown in FIG. 7, the treatment liquid recording head 14 is a set of two ejection ports (nozzles) 29 for one ink chamber 28 in which ejection energy generating elements such as heating elements (not shown) are arranged. The nozzle set is arranged at a density of 600 dpi. The discharge amount is 2 pl per nozzle, that is, a total of 4 pl per nozzle set according to the drive of the discharge energy generating element.

  In this embodiment, as shown in FIG. 6, two treatment liquid dots D2 (hatched) are applied to the ink dots D1 (indicated by white circles) to be formed on the transfer drum 1 that is an intermediate transfer member. Are shown). Specifically, the logical sum of the recording data corresponding to each color ink is taken in the same manner as described above, and in this embodiment, the processing liquid recording head 14 is driven using this logical sum data as the processing liquid data.

  As a result, also in this embodiment, two treatment liquids are applied to one dot of ink, and there is a probability that the ink and the treatment liquid will meet even if the landing position shifts in the ink and / or the treatment liquid. Since it increases compared to the prior art, basically the same effect as in the above example can be obtained. Further, in the present embodiment, once the logical sum data is obtained, there is no need for processing for creating processing liquid data thereafter, so that there is an advantage that data processing is simplified and time is shortened.

  In this embodiment, the number of nozzle ports of the processing liquid recording head is two. Although two ink nozzles are provided for one ink chamber 28, the present invention is not limited to this, and three or more nozzles may be used.

5. Other A mode in which at least two dots of the treatment liquid are formed in the ink dot formation range is not limited to the above-described embodiments. Moreover, it can also use combining suitably. For example, in the first embodiment in which the treatment liquid application density is greater than the ink application density with respect to the drum rotation direction, and the treatment liquid recording head has a nozzle arrangement density larger than the ink recording head. It is also possible to combine Example 2 in which the treatment liquid application density is increased. That is, it is possible to increase the application density of the treatment liquid in both the drum rotation direction and the nozzle arrangement direction.

  Further, the form of the intermediate transfer member to be used is not limited to the drum-like one as described above. Any surface layer of the intermediate transfer member can be used as long as it can be in line contact with the recording medium. For example, according to the form of the image forming apparatus to be applied or the transfer to the recording medium, a roller shape, a belt shape, a sheet The shape etc. can also be used. Further, not only those that are in line contact, but also a material having a large elastic deformation such as a pad used in pad printing can be used as the intermediate transfer member.

  Further, the type and number of color tones used for recording are not limited to the above. For example, in the above example, four inks including black in addition to the so-called three primary colors of cyan, magenta and yellow are used, but only cyan, magenta and yellow inks may be used. Instead of or in combination with these, red, green, blue or other colors may be used. In addition, inks of similar colors or different densities may be used, and the color tone referred to in this specification is a concept including density.

1 is a schematic cross-sectional view showing a schematic configuration of a main part of an image recording apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a schematic configuration example of a control unit system of the image recording apparatus illustrated in FIG. 1. 3 is a flowchart showing a recording processing procedure of the image recording apparatus shown in FIGS. 1 and 2. In the image recording apparatus shown in FIG. 1 and FIG. 2, an explanatory diagram for explaining a first specific example for appropriately applying a plurality of dots of processing liquid to one dot of data at the recording position. It is. In the image recording apparatus shown in FIGS. 1 and 2, an explanatory diagram for explaining a specific second embodiment for appropriately applying a plurality of dots of processing liquid to one dot of data at the recording position. It is. In the image recording apparatus shown in FIGS. 1 and 2, an explanatory diagram for explaining a specific third embodiment for appropriately applying a treatment liquid of a plurality of dots to one dot of data at the recording position. It is. It is a typical front view for demonstrating the structure of the recording head for process liquids used in 3rd Example shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transfer drum 2 Processing liquid application part 3 Ink application part 4 Ink image processing part 6 Recording medium separation part 5 Transfer part 7 Cleaning part 8 Recording medium 9 Paper feeding conveyance part 12 Support body 13 Surface layer 14 Processing liquid recording head 15, 15a, 15b, 15c, 15d Ink recording head 10 Paper discharge conveyance fixing unit 101 CPU
103 Memory 105 Interface (I / F)
110 Image supply device

Claims (7)

  In an image recording method for recording by ejecting ink onto an intermediate transfer member to form an image composed of ink dots and transferring the formed image to a recording medium, An image recording method comprising forming at least two dots of a treatment liquid for insolubilizing or aggregating the color material in the ink.   2. The image recording method according to claim 1, wherein dots of the at least two treatment liquids are formed prior to image formation on the intermediate transfer body based on recording data for determining the ink dot formation position. 3. .   3. The image recording method according to claim 1, wherein an amount of the processing liquid that forms the dots of the processing liquid is smaller than an amount of the ink that forms the ink dots. 4.   The image recording method according to claim 1, wherein the ink contains a pigment as a color material, and the treatment liquid contains a cationic substance.   5. The image recording method according to claim 1, wherein the processing liquid is a liquid containing at least a metal salt. In an image recording apparatus that forms an image of ink dots on an intermediate transfer member using an ink recording head for discharging ink, and performs recording by transferring the formed image to a recording medium.
A processing liquid applying unit that uses a processing liquid recording head for discharging a processing liquid that insolubilizes or aggregates the coloring material in the ink and forms at least two dots of the processing liquid with respect to the ink dot forming range. An image recording apparatus comprising: The ink recording head and the treatment liquid recording head have an array of ejection openings for performing ejection,
Means for moving the intermediate transfer member relative to the ink recording head and the processing liquid recording head in a direction different from the arrangement direction;
The processing liquid application unit drives the processing liquid head at a higher frequency than the ink recording head in the course of the relative movement, and / or has a higher arrangement density of ejection ports than the ink recording head. By using the treatment liquid head, at least two dots of the treatment liquid are formed with respect to the ink dot formation range in the relative movement direction and / or the arrangement direction of the discharge ports. The image recording apparatus according to claim 6.

Images