JP2019171870A - Recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress beading caused by melting of resin particles contained in ink applied earlier and affecting the penetration of ink applied later. SOLUTION: An ink containing first resin fine particles and an ink containing second resin fine particles having a lower glass transition temperature than the first resin fine particles, and an application amount of the ink containing the first resin fine particles is provided. The amount of application in the first printing scan performed in advance is larger than the amount of application in the subsequent second printing scan performed, and the amount of application of the ink including the second resin fine particles is Image data is generated such that the applied amount in one printing scan is smaller than the applied amount in the second printing scan. [Selection diagram] Fig. 4

Description

  The present invention relates to a recording apparatus that forms an image by ejecting ink.

  In an inkjet recording apparatus, it is generally necessary to increase the amount of ink applied to a recording medium in order to improve image performance (color development). On the other hand, in a full multi-structure ink jet recording apparatus having a heat fixing device for evaporating ink, the amount of water that can be processed (dried) at a time by the heat fixing device is limited due to restrictions on the power that can be used. . Therefore, a method of forming an image by dividing the recording into a plurality of times of recording and thermal fixing can be considered. However, in particular, in an ink system in which the resin fine particles contained in the ink are melted by heat fixing to develop fastness such as marker resistance, the resin particles contained in the ink applied in advance are melted and applied subsequently. Affects ink penetration. As a result, beading occurs.

  As a technique for suppressing beading, there has been proposed a prior art for separating the dot position of the ink to be applied in advance from the dot position of the ink to be applied subsequently. In Patent Document 1, image data is divided into a plurality of divided image data, and a liquid region corresponding to image data ejected in advance is separated from a liquid region corresponding to an image ejected subsequently. Is described as controlling.

JP2015-189115A

  However, Patent Document 1 discloses an example in which the image data is divided into five or more image data. For example, when the number of divisions is as small as two and the amount of applied ink is large, the dots are separated. There is a problem that I can not finish. In such a case, it becomes difficult to suppress beading due to melting of the resin particles contained in the previously applied ink.

  The present invention has been made in view of the above, and an object of the present invention is to suppress beading of ink applied to a recording medium in a scan after thermal fixing after the previous scan.

  A recording head that ejects a first ink containing first resin fine particles and a second ink containing second resin fine particles having a glass transition temperature lower than that of the first resin fine particles to apply ink to the recording medium; Based on the image data corresponding to the image to be recorded, the data for the first recording scan corresponding to the ink ejected in advance from the recording head in the first recording scan, and the data in the second recording scan Image processing means for generating data for the second recording scan that is subsequently ejected from the recording head, and the recording medium after the ink is applied in the first recording scan, and the second recording And a heating unit that heats the recording medium after the ink is applied in the scan, wherein the image processing unit is configured to apply the first ink in the first recording scan. The application amount of the first ink in the second recording scan is larger than the application amount of the second ink in the second recording scan. The image data is generated so as to be large.

  According to the present invention, the Tg of the resin particles contained in the ink with a large amount applied in advance is higher than the Tg of the resin particles contained in the ink with a large amount applied subsequently and is difficult to melt. For this reason, it is possible to suppress beading without inhibiting the penetration of the ink applied after the thermal fixing of the previously applied ink.

It is sectional drawing which showed the structure of the inkjet recording device of 1st embodiment. FIG. 3 is a diagram of the recording head according to the first embodiment observed from an ejection port surface. It is a block diagram which shows the recording control system of the inkjet recording device of 1st embodiment. 3 is a flowchart illustrating an image processing process in the ink jet recording apparatus according to the first embodiment. It is the flowchart which showed the data division processing process in 1st embodiment. It is the schematic diagram which showed an example of the data division | segmentation process in 1st embodiment. It is the flowchart which showed the recording operation in 1st and 2nd embodiment. It is the flowchart which showed the data division processing process in 2nd embodiment. It is the schematic diagram which showed an example of the data division | segmentation process in 2nd embodiment. It is the figure which showed the data thinning-out table in 2nd embodiment. 10 is a flowchart showing a recording operation in the third embodiment. It is the figure which showed the expansion | deployment table used for the binarization process in an image processing process. It is a typical perspective view of the inkjet recording device of 4th embodiment. It is sectional drawing of the inkjet recording device of 4th embodiment. It is the figure which observed the recording head in the fourth embodiment from the discharge port surface. FIG. 10 is a perspective view when a recording head according to a fourth embodiment is viewed from the ejection port surface side. It is a block diagram which shows the recording control system of the inkjet recording device of 4th embodiment. It is explanatory drawing of the pattern used for the quantization in 4th embodiment. It is a flowchart which shows the process of the data generation process in 4th embodiment. It is sectional drawing which showed the structure of the inkjet recording device of 4th embodiment. It is a schematic diagram which shows the mode of the multipass recording in 4th embodiment. It is a schematic diagram which shows the mode of the multipass recording in 4th embodiment.

[First embodiment]
Hereinafter, the first embodiment will be described.

(Device configuration)
FIG. 1 is a cross-sectional view showing the configuration of the ink jet recording apparatus according to the first embodiment.

  The recording head 10 includes four recording heads 10K, 10C, 10M, and 10Y that discharge black (K), cyan (C), magenta (M), and yellow (Y) in this order from the upstream side in the transport direction. . In the recording heads 10K, 10C, 10M, and 10Y, 12 discharge port substrates 20 having discharge ports 21 arranged along a direction orthogonal to the transport direction F as shown in FIG. Forming. FIG. 2 is a view of the recording head 10 as viewed from the discharge port side. Each discharge port substrate 20 has 1280 discharge ports formed at an interval of 1200 dpi, and as shown by 20a and 20b, 40 discharge ports at both ends overlap in the discharge port row direction of the adjacent discharge port substrates. The recording heads 10K, 10C, 10M, and 10Y are arranged so as to be positioned. The overlapping nozzle functions effectively as a discharge port array having a discharge port array length of 12 inches by distributing and discharging image data to the discharge ports existing at positions overlapping in the discharge port array direction. Can support paper width recording. The amount of ink ejected from each ejection port 21 at a time is about 4 ng. Recording is performed by ejecting ink from the ejection ports 21 to the recording medium 14 at an ejection frequency of 10.5 kHz.

  The recording medium 14 is fed from the paper feed tray 12 by the paper feed roller 13. The recording medium is transported to a position facing the recording head 10 by a transport roller 16 disposed in the transport path, recorded, and then heated by a heat fixing device 15. In the ink jet recording apparatus, an image is formed by two recording scans (two passes), and after performing the first pass recording scan including recording and heating, the recording medium 14 is transported by the transport path switching actuator 17 to the transport path F1. The second scanning scan is performed. Further, when the image formation is completed, the transport path is switched by the transport path switching actuator 17 and discharged to the discharge tray 18. The recording medium 14 is conveyed at a conveyance path of 8.75 inches / second and ink is ejected from each ejection port 21 at a frequency of 10.5 kHz. Therefore, the recording medium 14 has a recording resolution of 1200 dpi also in the conveyance direction. An image is recorded.

  The heat fixing unit 15 is a hot pressure roller, and includes a roller 15B facing a heating roller 15A having a heat source therein, and the recording medium is heated by the heating roller 15A when the recording medium 14 passes between 15A and 15B. Then, heat fixing is performed. The thermal fixing device according to the first embodiment is configured to be able to heat the surface temperature of the recording medium being conveyed to 200 ° C. In each scan, the recording medium is heated so that the surface temperature of the portion to which ink is not applied becomes 200 ° C.

(Ink composition)
Next, the ink used in this embodiment will be described. Hereinafter, “parts” and “%” are based on mass unless otherwise specified.

  Any of the inks containing pigments used in this embodiment contains a water-soluble organic solvent. The water-soluble organic solvent preferably has a boiling point of 150 ° C. or higher and 300 ° C. or lower because of the wettability and moisture retention of the head face surface. Moreover, the following is mentioned from a viewpoint of the function of the film-forming aid with respect to resin fine particles. Ketone compounds such as acetone and cyclohexanone, and propylene glycol derivatives such as tetraethylene glycol dimethyl ether. In addition, heterocyclic compounds having a lactam structure represented by N-methyl-pyrrolidone and 2-pyrrolidone are particularly preferable. From the viewpoint of discharge performance, the content of the water-soluble organic solvent is preferably 3 wt% or more and 30 wt% or less. Specific examples of the water-soluble organic solvent include the following. For example, alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol. Amides such as dimethylformamide and dimethylacetamide. Ketones or ketoalcohols such as acetone and diacetone alcohol. Ethers such as tetrahydrofuran and dioxane. Polyalkylene glycols such as polyethylene glycol and polypropylene glycol. ethylene glycol. Alternatively, alkylene glycols in which an alkylene group contains 2 to 6 carbon atoms, such as propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol. Lower alkyl ether acetates such as polyethylene glycol monomethyl ether acetate. Glycerin. Lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether. Polyhydric alcohols such as trimethylolpropane and trimethylolethane. N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned. The above water-soluble organic solvents can be used alone or as a mixture. Moreover, it is desirable to use deionized water as water. In addition to the above-described components, a surfactant, an antifoaming agent, a preservative, an antifungal agent, and the like can be appropriately added to the ink used in order to have desired physical property values as necessary.

-Preparation of aqueous resin fine particle dispersion "Resin fine particles" mean polymer fine particles present in a state of being dispersed in water. Specifically, acrylic resin fine particles synthesized by, for example, emulsion polymerization of monomers such as (meth) acrylic acid alkyl ester and (meth) acrylic acid alkylamide are exemplified. Further, styrene-acrylic resin fine particles synthesized by emulsion polymerization of a styrene monomer with (meth) acrylic acid alkyl ester, (meth) acrylic acid alkylamide, or the like can be mentioned. In addition, polyethylene resin fine particles, polypropylene resin fine particles, polyurethane resin fine particles, styrene-butadiene resin fine particles and the like can be mentioned.

  In addition, “polymer fine particles present in a state dispersed in water” means a resin fine particle form obtained by homopolymerizing or copolymerizing plural types of monomers having a dissociable group, so-called self-dispersing resin fine particle dispersion. It may be the body. Here, examples of the dissociable group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and examples of the monomer having the dissociable group include acrylic acid and methacrylic acid. Furthermore, a so-called emulsified dispersion type resin fine particle dispersion in which resin fine particles are dispersed with an emulsifier may be used. As an emulsifier, a material having an anionic charge can be used regardless of a low molecular weight or a high molecular weight.

  Hereinafter, in the first embodiment, resin fine particles having a sulfonic acid group will be described as an example. The resin component constituting the resin fine particle is not particularly limited as long as it is a resin containing a sulfonic acid group, and may be any resin component such as any commonly used natural or synthetic polymer, or a newly developed polymer. But it can be used without restriction. In particular, from the viewpoint of being able to be used generally and simplifying functional design of resin fine particles, acrylic resins and styrene / acrylic resins are used, and polymers or copolymers of monomer components having radically polymerizable unsaturated bonds are used. Merge can be used.

  Examples of the hydrophilic radically polymerizable unsaturated monomer having a sulfonic acid group (hereinafter referred to as a monomer) include styrene sulfonic acid. Examples thereof include sulfonic acid-2-propylacrylamide, acrylic acid-2-ethyl sulfonate, methacrylic acid-2-ethyl sulfonate, butylacrylamide sulfonic acid and salts thereof.

  Moreover, the following are mentioned as a hydrophilic monomer other than the said monomer which has a sulfonic acid group. For example, monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, fumaric acid and the like and salts thereof. Alternatively, a monomer having a phosphonic acid group such as methacrylic acid-2-ethyl phosphonate and acrylic acid-2-ethyl phosphonate may be used together.

  Moreover, the following are mentioned as a monomer classified as a hydrophobic monomer. For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid-n-propyl, acrylic acid-n-butyl, acrylic acid-t-butyl, benzyl acrylate. Such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, methacrylate-n-propyl, methacrylate-n-butyl, isobutyl methacrylate, tert-butyl methacrylate, tridecyl methacrylate, benzyl methacrylate, etc. ) Acrylic acid ester. Styrenic monomers such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-tert-butylstyrene and the like. Itaconic acid esters such as benzyl itaconate. Maleate esters such as dimethyl maleate. Fumarate esters such as dimethyl fumarate; acrylonitrile, methacrylonitrile, vinyl acetate and the like. In addition, various known or novel oligomers and macromonomers can be used without limitation.

  Since the radical polymerizable monomer used in the production method according to the embodiment is a component constituting resin fine particles having a sulfonic acid group through aqueous precipitation polymerization, it may be appropriately selected depending on the characteristics of the resin fine particles to be obtained. In the production method, any conventionally known radical polymerizable monomer can be used.

  In particular, the resin fine particles having a sulfonic acid group are preferably composed of a copolymer of monomer components including a hydrophilic monomer having at least one type of sulfonic acid and at least one type of hydrophobic monomer, as described above. . Then, it is preferable at the point which obtains the ink for water-based inkjet recording which has a dispersion stability and a suitable printing characteristic. That is, when preparing resin fine particles, various characteristics of the resin fine particles are appropriately determined depending on many control factors such as the type and concentration of the polymerization initiator to be used, the type of monomer to be constituted and the copolymerization ratio. It is possible to control.

  The radical polymerization reaction conditions vary depending on the properties of the polymerization initiator, the dispersant, and the monomer used. For example, the reaction temperature is 100 ° C. or lower, preferably 40 ° C. or higher and 80 ° C. or lower. The reaction time is 1 hour or more, preferably 6 hours or more and 30 hours or less. The stirring speed during the reaction is from 50 rpm to 500 rpm, preferably from 150 rpm to 400 rpm.

  In particular, when obtaining resin fine particles having a sulfonic acid group by polymerizing at least one hydrophobic monomer and a hydrophilic monomer containing at least a sulfonic acid group, preferably the monomer component is an aqueous radical polymerization initiator. It is desirable to drop it into the aqueous dispersion. In order to uniformly obtain resin fine particles having a desired sulfonic acid group from a mixture of monomers having different properties such as a hydrophobic monomer and a hydrophilic monomer, the copolymerization ratio of the monomers having different properties should always be kept constant. Is desirable. When the mixture of monomers is added to the polymerization system in excess of the amount of monomer consumed in the polymerization reaction within a certain time, only a specific monomer species is polymerized in advance, and the remaining monomers are polymerized in advance. There is a tendency to polymerize after the spent monomer is consumed. In this case, large nonuniformity occurs in the properties of the resin fine particles having sulfonic acid groups to be generated.

  A resin particle dispersion (resin content is 20.0 mass%) having a glass transition point shown in Table 1 can be obtained by adjusting the copolymerization ratio and polymerization time as described above.

  Ink can be produced as follows using the resin particle dispersion shown in Table 1.

Preparation of black ink (1) Preparation of dispersion First, anionic polymer P-1 [styrene / butyl acrylate / acrylic acid copolymer (polymerization ratio (weight ratio) = 30/40/30) acid value 202, Weight average molecular weight 6500] is prepared. This is neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to produce a homogeneous 10% by mass polymer aqueous solution.

  Then, 600 g of the polymer solution, 100 g of carbon black, and 300 g of ion-exchanged water are mixed and mechanically stirred for a predetermined time, and then the non-dispersed material including coarse particles is removed by centrifugal treatment to obtain a black dispersion liquid. To do. The resulting black dispersion has a pigment concentration of 10% by mass.

(2) Preparation of ink The following components were added to the above black dispersion, sufficiently mixed and stirred, and then pressure-filtered with a microfilter (made by Fujifilm) having an asize of 2.5 μm to obtain a pigment concentration of 4% by mass. A pigment ink is prepared. With respect to the resin fine particle dispersion, ink is prepared for each of the resin fine particle dispersions 1 and 2. In this way, two types of black ink to be used were prepared.
40 parts of the above black dispersion liquid part of the above resin fine particle dispersion 20 parts glycerin 10 parts triethylene glycol 10 parts 2-pyrrolidone 5 parts acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part ion-exchanged water remainder

-Preparation of cyan ink (1) Preparation of dispersion First, using benzyl acrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 250 and a number average molecular weight of 3000 is prepared by a conventional method. Mix and dilute with ion exchange water to make a homogeneous 50 wt% polymer aqueous solution.

  200 g of the polymer solution, C.I. I. 100 g of Pigment Blue 15: 3 and 700 g of ion-exchanged water are mixed and mechanically stirred for a predetermined time, and then a non-dispersed material including coarse particles is removed by a centrifugal separation process to obtain a cyan dispersion. The obtained cyan dispersion has a pigment concentration of 10% by mass.

(2) Preparation of ink For the preparation of ink, the above cyan dispersion is used. The following components are added to the above cyan dispersion, and after sufficiently mixing and stirring, pressure filtration is performed with a microfilter (manufactured by Fuji Film) having a pore size of 2.5 μm to prepare a pigment ink having a pigment concentration of 4% by mass. With respect to the resin fine particle dispersion, ink is prepared for each of the resin fine particle dispersions 1 and 2. Thus, two types of cyan inks used in the embodiment were produced.
40 parts of the above cyan dispersion liquid 20 parts of the above resin fine particle dispersion 20 parts glycerin 10 parts diethylene glycol 10 parts 2-pyrrolidone 5 parts acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part ion-exchanged water remainder

-Preparation of magenta ink (1) Preparation of dispersion First, using benzyl acrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 300 and a number average molecular weight of 2500 is prepared by a conventional method. Mix and dilute with ion exchange water to make a homogeneous 50 wt% polymer aqueous solution.

  100 g of the polymer solution, C.I. I. 100 g of Pigment Red 122 and 800 g of ion-exchanged water are mixed and mechanically stirred for a predetermined time, and then a non-dispersed material containing coarse particles is removed by centrifugation to obtain a magenta dispersion. The obtained magenta dispersion has a pigment concentration of 10% by mass.

(2) Preparation of ink The ink is prepared using the magenta dispersion. The following components are added to the above magenta dispersion, and after sufficiently mixing and stirring, pressure filtration is performed with a microfilter (manufactured by Fuji Film) having a pore size of 2.5 μm to prepare a pigment ink having a pigment concentration of 4% by mass. The ink is adjusted for each of the resin fine particle dispersions 2 and 3. As described above, two types of magenta inks used in the embodiment were produced.
40 parts of the above magenta dispersion 20 parts of the above resin fine particle dispersion 20 parts glycerin 10 parts diethylene glycol 10 parts 2-pyrrolidone 5 parts acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part ion-exchanged water remainder

Preparation of yellow ink (1) Preparation of dispersion First, the anionic polymer P-1 is neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10% by mass polymer aqueous solution. .

  300 g of the polymer solution, C.I. I. 100 g of Pigment Yellow 74 and 600 g of ion-exchanged water are mixed and mechanically stirred for a predetermined time, and then a non-dispersed material containing coarse particles is removed by a centrifugal separation process to obtain a yellow dispersion. The resulting yellow dispersion has a pigment concentration of 10% by mass.

(2) Preparation of ink The following components are mixed, sufficiently stirred, dissolved and dispersed, and then filtered under pressure through a microfilter (manufactured by Fuji Film) having a pore size of 1.0 μm, and a pigment having a pigment concentration of 4 mass%. Prepare ink. The ink is adjusted for each of the resin fine particle dispersions 2 and 3. Thus, two types of yellow inks used in the embodiment were produced.

40 parts of the above yellow dispersion liquid 20 parts of the above resin fine particle dispersion 20 parts glycerin 9 parts ethylene glycol 10 parts 2-pyrrolidone 5 parts acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part ion-exchanged water remainder In the obtained ink, Tg of resin particles contained in black ink and cyan ink is higher than Tg of resin particles contained in magenta ink and yellow ink.

(Configuration of control system of recording system)
As shown in FIG. 3, the control unit 30 in the ink jet recording apparatus of this embodiment includes a gate array 304, a CPU 301, a ROM 302, and a RAM 303. The interface 306 is used to input image data from the external device 305. The ROM 302 functions as a memory that stores a program for controlling the recording apparatus and processing image data executed by the CPU 301. The RAM 303 stores various data (image data, a recording signal supplied to the recording head, etc.) used for controlling the ink jet recording apparatus. The gate array 304 supplies a recording signal to the recording head 308 and also transfers data between the interface 306, the CPU 301, and the RAM 303. The recording head driver 307 drives the recording head 308 in accordance with the recording signal output from the control unit 30 to discharge ink. In addition, the motor driver 309 drives the transport motor 310 in accordance with the signal output from the control unit 30 and performs a recording medium transport operation. The actuator driver 311 also switches the conveyance path by driving the conveyance path switching actuator 312 in accordance with a signal from the control unit 30. The gate array 304 and the CPU 301 of this control unit convert the image data received from the external device 305 via the interface 306 into recording data and store it in the RAM 303. Further, the control unit 30 performs the recording operation of the recording head and the conveyance operation of the recording medium by driving the motor driver 309 and the recording head driver 307 in synchronization. Thereby, a recorded image corresponding to the recorded data is formed on the recording medium.

(Image processing)
FIG. 4 is a flowchart showing a flow of image processing executed by the CPU 301 in the first embodiment. Note that the image processing described below can be executed by a plurality of processors. It can also be executed using a plurality of memories.

  Specifically, first, RGB multi-valued image data is input from the external device 305 in step 401, and acquired.

  The obtained multi-value image data in RGB format is subjected to ink color separation processing in step 402, and multi-value image data corresponding to each of a plurality of types of ink (K, C, M, Y) used for image formation. The data is converted into certain KCMY data and temporarily stored in the RAM 303. In the present embodiment, each ink is converted into quinary data in units of 600 dpi pixels.

  In step 403, the temporarily stored KCMY data is acquired by reading from the RAM 303.

  In step 404, data is generated by dividing the KCMY data into image data (first recording scan data) recorded in the first pass and image data (first recording scan data) recorded in the second pass. . The five-valued multi-value data 0 to 4 correspond to the number of dots (0 to 4 dots) in 600 dpi pixel units.

  In the binarization process in step 405, the five-valued multi-value data is developed into binary print data in units of 1200 dpi, which is the print resolution in the ejection port and the transport direction, according to the pattern shown in FIG.

  In step 406, the generated recording data is stored in the RAM 303 or a predetermined memory having a buffer function. This data is transmitted to the recording head driver at an appropriate timing.

  FIG. 5 is a diagram showing a data generation process performed by the CPU 301 in the first embodiment.

  In step 501, KCMY data is acquired.

  In step 502, it is determined whether the recording scan is the first pass or the second pass. In this embodiment, the K and C image data is divided into the first pass recording data, and the M and Y image data is divided into the second pass image data. In Steps 503 and 505, the ink that is not recorded in each pass is divided. Set color image data to zero.

  Then, the first-pass KCMY data generated in step S504 is stored in the RAM 303 so that it can be read out by the binarization processing in step 405. In step 506, the second-pass KCMY data is stored in the RAM 303 so that it can be read out by the binarization process in step 405.

  FIG. 6 is a diagram showing an example of the data generation process shown in FIG. According to FIG. 5, the KCMY data 501 is divided into KCMY data in each pass, and the hatched pixels are changed in 503 and 505.

(Recording operation)
FIG. 7 is a diagram showing a recording operation process in the first embodiment. The recording operation in the first embodiment will be described with reference to FIG. 7 and FIG.

  In step 701, the recording medium is fed from the paper feed tray 12 by the paper feed roller 13.

  In step 702, the fed recording medium is conveyed to a position facing the recording head 10, and ink is ejected from the recording head 10 to the conveyed recording medium. The ink applied in the first pass is ejected from the recording head 10 based on the recording data 504 in FIG. Thereafter, the recording medium is conveyed to the heat fixing device 15 and heated.

  After the first-pass recording and the recording scan consisting of thermal fixing, in step 703, the transport path switching actuator 17 is driven to transport the recording medium to the transport path F1 in order to perform the second-pass recording scan in step 704.

  In step 705, the recording medium transported to F <b> 1 is transported again to a position facing the recording head 10. Here, the second-pass ink is applied from the recording head to the transported recording medium, and then the ink is thermally fixed by the thermal fixing device 15. The ink applied here is ejected from the recording head 10 based on the recording data at 506 in FIG.

  In step 706, the recording medium that has been recorded by the second-pass recording scan is transported to the transport path F <b> 2 by switching the transport path switching actuator 17, and discharged to the discharge tray 18 in step 706.

  Table 2 summarizes the Tg of the resin fine particles in the combination of the inks used in the first embodiment, the marker resistance of the obtained image, and the qualitative evaluation of the image quality. In the ink jet recording apparatus, the glass transition temperature Tg1 of the resin fine particles contained in the ink applied in the preceding pass is higher than the glass transition temperature Tg2 of the resin fine particles contained in the ink applied in the subsequent pass. The difference between Tg1 and Tg2 is preferably 20 ° C. or higher. As described above, according to this embodiment, since the Tg1 of the resin fine particles applied in the preceding pass is relatively high and difficult to melt, the ink applied in the subsequent pass does not melt in the heat fixing of the preceding pass. Does not affect the penetration of For this reason, it is possible to form a good image without deteriorating beading in recording in subsequent passes. Further, an image excellent in marker property can be obtained by the effect of the melted resin particles.

  In this embodiment, the Tg of the resin fine particles contained in the ink is preferably lower than the surface temperature of 200 ° C. of the recording medium heated by the thermal fixing device in each scan.

  Further, in the first embodiment, the relatively fine Tg resin fine particles are included, and the lightness of the dots of ink applied in advance is low, and the lightness of the ink that is applied subsequently including low Tg resin fine particles is included. Lower than the brightness of the dot. Thus, it is preferable from the viewpoint of the graininess of an image related to beading that the lightness of the dots of ink applied in advance is low. However, when it is desired to obtain particularly strong marker resistance in the K ink, it is also possible to use a low Tg resin fine particle in the K ink to provide an ink that is subsequently applied.

[Second Embodiment]
In the first embodiment, the resin fine particles contained in the ink applied in the first pass by applying the ink containing the high Tg resin fine particles in the first pass and applying the low Tg ink in the second pass. The image adverse effect caused by the inhibition of the permeation of the ink applied in the second pass due to was suppressed. In the first embodiment, all the image data of the ink containing the low Tg emulsion is given in the second pass, but even if a part of the image data is divided in the first pass, an image with good beading and robustness can be formed. It is. Especially in areas where the amount of ink applied is large in the same area in the second pass for secondary colors, dividing some image data in the first pass is advantageous for moisture treatment by heat fixing, and is more favorable in terms of robustness. An image can be formed. However, since the ink application amount in the same area in the first pass after the data is divided is increased, the ink application quantity in the same area in the first pass is equal to or less than the threshold value so as not to inhibit the moisture treatment in the first pass. In this case, 1-pass data can be divided.

  The image processing and recording operation in the second embodiment will be described below. Unless otherwise noted, the basic configuration of the apparatus is the same as that of the first embodiment.

(Image processing)
FIG. 8 is a diagram showing a data generation process in the second embodiment. In the second embodiment, in step 803 and step 808, the threshold value of each pixel (600 dpi unit) of the KCMY data is determined.

  First, in step 801, KCMY data is acquired.

  Next, in step 802, it is determined whether or not the data processing is for the first pass. If it is the first pass, the process proceeds to step 803.

  In step 803, in the first pass, the sum of the number of M and Y dots in the pixel is greater than or equal to a threshold value (here, 4), and the number of K and C dots that are data in the first pass is less than or equal to the threshold value ( Here, it is determined whether it is zero). If the condition is satisfied, the process proceeds to step 804.

  In step 804, the M dots that exceed the threshold (here, 4) in 804 are divided as image data for the first pass. It is preferable to preferentially divide the M data with relatively low dot brightness in the first pass from the viewpoint of less noticeable when beading occurs in the second pass than in the Y division. Then, the process proceeds to Step 806.

  In step 806, the image data divided in the first pass is subjected to dot thinning processing using the conversion table shown in FIG. This is a process for suppressing color change due to image formation by dividing into two passes.

  In step 802, a determination is made to generate data for the second pass. In the second pass, if the condition is satisfied by the same threshold determination as in step 803 of the first pass, the remaining M data of the data divided in the first pass is set as M image data of the second pass.

  FIG. 9 is a diagram showing an example of the data generation process shown in FIG. A threshold determination (steps 803 and 808) is performed on the KCMY data acquired in step 803. Diagonal hatching is a pixel with K + C = 0, and rhombus hatching is a pixel with M + Y> 4. The M data generated by dividing the pixel in accordance with the threshold determination in the processes of Steps 804 and 809 are halftone hatched pixels. In the example of FIG. 9, the maximum number of M dots that exceed the threshold is 2. Therefore, the number of dots does not change in the thinning process performed in step 806 based on the table of FIG. 10. These data division processes are performed, and KCMY data for each path is acquired in steps 807 and 811. The image processing process and the recording operation other than the process in the data division process are the same as those described in the first embodiment.

[Third embodiment]
In the first embodiment and the second embodiment, the image data of the ink containing resin fine particles having different Tg is divided and applied in the first pass and the second pass, so that beading / robustness is achieved. A good image was formed. In the third embodiment, an example will be described in which only heat fixing is performed in the third pass in order to develop higher fastness when the ink application amount increases.

  When the amount of applied ink increases, higher fastness can be obtained by applying more heat from the viewpoint of moisture treatment. Therefore, in the third embodiment, when the number of dots is equal to or larger than the threshold value in a predetermined region, scanning is performed in which only thermal fixing is performed without applying ink in the third pass.

  A recording operation in the third embodiment will be described with reference to FIG. The steps up to the second pass printing scan in step 1104 are the same as those in the first embodiment and the second embodiment, and the data division process may adopt either process shown in FIG. 5 or FIG. . In the third embodiment, there is an area where the sum of the number of dots for each ink exceeds 4 dots in 600 dpi pixel units in the KCMY data after the data generation processing 404 in the first recording scan and the second recording scan in Step 1105. Determine if there is. If there is a pixel exceeding the threshold value, an image having better robustness can be formed by adding a scan (step 1106) that does not apply ink in the third pass when the amount of applied ink is large. it can.

  The subsequent steps are the same as in the second embodiment.

  In the present embodiment, the threshold determination is performed for each 600 dpi pixel. However, it is also possible to determine the threshold for each predetermined region using a pixel group including a plurality of pixels as a predetermined region.

[Fourth embodiment]
In the first, second, and third embodiments of the present invention, the embodiment of the present invention is shown in a full-multi ink jet recording apparatus. However, the present invention can also be implemented in a serial ink jet recording apparatus. . A fourth embodiment in the case of a serial type ink jet recording apparatus will be described below.

(Device configuration)
Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 13 is a partially exploded perspective view illustrating the internal mechanism of the ink jet recording apparatus 1300 according to the present embodiment.

  As shown in FIG. 13, the recording medium 1301 is transported in the direction of arrow F as the sub-scanning motor (not shown) is driven. Further, the guide shaft 1302 is disposed so as to extend in a direction orthogonal to the conveyance direction F (sub-scanning direction) of the recording medium 1301. The carriage 1303 on which the recording head 1600 is mounted is reciprocated (reciprocated) in the direction of arrow S (main scanning direction) in the figure by driving a main scanning motor (not shown) while being supported by the guide shaft 1302. The recording head 1600 mounted on the carriage 1303 discharges ink onto the recording medium according to the recording data during the moving scan of the carriage 1303, and recording on the recording medium is performed.

  In the ink jet recording apparatus 1300 of the present embodiment, so-called bidirectional recording is performed in which ink is ejected to record on a recording medium both when the recording head 1306 moves along the forward path and when it moves along the return path. The method is adopted. When scanning with one recording by the recording head 1306 is performed, the recording medium 1301 is conveyed by a predetermined amount in the conveying direction F by a sub-scanning motor (not shown). The recording medium is heated by a platen heater 1304 in a region where the recording head operates while being conveyed, and further by a cure heater including a hot air blowing mechanism (not shown) and a back heater 1305 on the downstream side in the conveying direction. The surface of the recording medium is heated to 100 ° C. by the platen heater, the hot air drying mechanism and the back surface heater.

  When a recording operation command is input from an externally connected host computer, the recording medium 1301 is fed to a recordable position by a recording head 1306 mounted on the carriage 1303. Thereafter, the main scanning of the recording head 1306 while discharging ink in accordance with the recording signal and the conveying operation of a predetermined amount of the recording medium are alternately repeated, so that a plurality of recording heads 1306 are applied to the unit area on the recording medium. An image is formed by performing scanning twice.

  FIG. 14 is a schematic sectional view of the ink jet recording apparatus 1300 shown in FIG. The recording medium transported in the transport direction F is heated while being transported by a cure heater including a platen heater 1304, a hot air blowing mechanism 1401, and a back surface heater 1305.

  FIG. 15 is a schematic diagram showing a state in which the configuration of the discharge port forming substrate 1500 of the recording head 1306 used in the fourth embodiment of the present invention is observed from the discharge port side. In the recording head 1306, an ejection port array for one color is formed by ejection ports 1501 arranged in the sub-scanning direction at a density of 1200 per inch. FIG. 16 is a perspective view of the configuration of the recording head 1306 when viewed from the top surface of the recording head 1306. In the fourth embodiment of the present invention, six discharge port array forming substrates shown in FIG. 15 are mounted, each of which includes a processing liquid discharge port column 1500R, a black discharge port column 1500K, and a cyan discharge port column 1500C. , A magenta discharge port array 1500M, a yellow discharge port array 1500Y, and a clear ink discharge port array 1500CL. The treatment liquid is a liquid having a function of reacting when mixed with the color ink to promote pigment aggregation of the color ink. In the fourth embodiment of the present invention, an image is formed using two positions of 1152 upstream and 384 downstream in the number of ejection openings in the recording medium conveyance direction. In this manner, by using a part of the ejection port array, it is possible to control the order of ink application. In the fourth embodiment of the present invention, treatment liquid, black, cyan, magenta, and yellow ink are applied to the recording medium in this order, and then transparent ink is applied in this order. The treatment liquid is mixed on the color ink recording medium, thereby destroying the dispersion of the pigment contained in the color ink. By using the treatment liquid, there is an effect of leaving a large amount of pigment on the recording medium and improving the optical density. Further, by applying the clear ink after the color ink, there is an effect of improving the robustness of the image and the image quality (such as gloss) compared with the case where only the color ink is applied. The droplet discharged from each discharge port is about 4 ng. The recording apparatus according to the first embodiment of the present invention discharges such a recording head 1306 while scanning in the main scanning direction, thereby recording at 2400 dpi (dot / inch) in the main scanning direction and 1200 dpi in the sub-scanning direction. Record dots at density. Therefore, in the fourth embodiment of the present invention, if the amount of 1 dot applied to a 1200 dpi square area per ejection port array is 100%, recording at a maximum recording density of 200% is possible.

(Ink composition)
Next, the ink used in this embodiment will be described. The solvent, water-soluble resin, and the like described in the first embodiment are the same. Hereinafter, the creation of ink in the present embodiment will be described.

-Preparation of black ink Add the following components to the black dispersion liquid and the resin dispersion 1 liquid described in the first embodiment, sufficiently mix and stir, and then apply to an Asize 2.5 μm microfilter (manufactured by Fuji Film). And pressure-filtering to prepare a pigment ink having a pigment concentration of 2% by mass.
Black dispersion 20 parts Resin fine particle dispersion 1 part 50 parts 2-methyl-1, 3-propanediol 5 parts 2-pyrrolidone 15 parts Acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part Ion-exchanged water remainder

-Preparation of cyan ink For the preparation of ink, the cyan dispersion liquid and the resin dispersion 1 liquid described in the first embodiment are used. The following components are added to the above-mentioned cyan dispersion, and after sufficiently mixing and stirring, pressure filtration is performed with a micro filter (manufactured by Fuji Film) having a pore size of 2.5 μm to prepare a pigment ink having a pigment concentration of 2 mass%.
Cyan dispersion 20 parts Resin fine particle dispersion 1 part 50 parts 2-methyl-1, 3-propanediol 5 parts 2-pyrrolidone 15 parts Acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part Ion-exchanged water The rest

-Preparation of magenta ink The ink is prepared using the magenta dispersion liquid and the resin dispersion liquid 1 described in the first embodiment. The following components are added to the above magenta dispersion, and after sufficiently mixing and stirring, pressure filtration is performed with a micro filter (manufactured by Fuji Film) having a pore size of 2.5 μm to prepare a pigment ink having a pigment concentration of 2 mass%.
Magenta dispersion 20 parts Resin fine particle dispersion 1 part 50 parts 2-methyl-1,3-propanediol 5 parts 2-pyrrolidone 15 parts Acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part Ion-exchanged water remainder

-Preparation of yellow ink Preparation of the ink uses the yellow dispersion liquid and the resin dispersion 1 liquid described in the first embodiment. The following components are mixed, sufficiently stirred and dissolved / dispersed, followed by pressure filtration with a micro filter (manufactured by Fuji Film) having a pore size of 1.0 μm to prepare a pigment ink having a pigment concentration of 3 mass%.
30 parts of the above yellow dispersion liquid 50 parts of the above resin particle dispersion liquid 50 parts 2-methyl-1, 3 propanediol 5 parts 2-pyrrolidone 15 parts acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part ion-exchanged water remainder

-Preparation of treatment liquid After sufficiently mixing and stirring the following components, pressure treatment is performed with a micro filter (manufactured by Fuji Film) having a pore size of 2.5 μm to prepare a treatment liquid.
Calcium methanesulfonate 4 parts 2-methyl-1,3-propanediol 5 parts 2-pyrrolidone 15 parts Acetylene glycol EO adduct (manufactured by Kawaken Fine Chemicals Co., Ltd.) 1.0 part ion-exchanged water remainder

-Preparation of clear ink Preparation of ink is performed with respect to each of the resin dispersion 2 liquid and the resin dispersion 3 liquid described in the first embodiment. The following components are added to the resin dispersion liquid, and after sufficiently mixed and stirred, pressure filtration is performed with a micro filter (manufactured by Fuji Film) having a pore size of 2.5 μm to prepare a clear ink. As described above, two types of clear ink used in the present embodiment were adjusted.
50 parts of the above resin fine particle dispersion liquid 2-methyl-1, 3-propanediol 5 parts 2-pyrrolidone 15 parts Acetylene glycol EO adduct (manufactured by Kawaken Fine Chemical Co., Ltd.) 1.0 part ion-exchanged water remainder As described above Regarding the prepared ink, the Tg of the resin contained in black, cyan, magenta, and yellow is higher than the Tg of the resin contained in the clear ink.

(Configuration of control system of recording system)
As shown in FIG. 17, the control unit 1700 in the ink jet recording apparatus of this embodiment includes a gate array 1704, a CPU 1701, a ROM 1702, and a RAM 1703. The interface 1706 is used to input image data from the external device 1705. The ROM 1702 functions as a memory that stores a program for controlling the recording device and processing image data executed by the CPU 1701. The RAM 1703 stores various data (image data, a recording signal supplied to the recording head, etc.) used for controlling the ink jet recording apparatus. The gate array 1704 supplies a recording signal to the recording head 1708 and also transfers data between the interface 1706, the CPU 1701, and the RAM 1703. The recording head driver 1707 drives the recording head 1708 in accordance with the recording signal output from the control unit 1700 to discharge ink. In addition, the motor driver 1711 drives the carriage motor 1710 in accordance with the signal output from the control unit 1700 to perform main scanning of the carriage. The motor driver 1709 drives the transport motor 1710 in accordance with the signal output from the control unit 1700 to transport the recording medium. The gate array 1704 and the CPU 1701 of this control unit convert image data received from the external device 1705 via the interface 1706 into recording data and store it in the RAM 1703. Further, the control unit 1700 drives the motor drivers 1709 and 1711 and the recording head driver 1707 in synchronization to perform the recording operation of the recording head, the main scanning of the carriage, and the conveying operation of the recording medium. Thereby, a recorded image corresponding to the recorded data is formed on the recording medium.

(Image processing)
Also in the fourth embodiment of the present invention, the flow of image processing executed by the CPU 1701 is the flowchart shown in FIG. Note that the image processing described below can be executed by a plurality of processors. It can also be executed using a plurality of memories.

  Specifically, in the image processing in the fourth embodiment, first, RGB multi-valued image data is input from the external device 1705 in step 401 and is acquired.

  The obtained multi-value image data in RGB format is subjected to ink color separation processing in step 402, and multi-value image data corresponding to each of a plurality of types of ink (K, C, M, Y) used for image formation. Convert to some KCMY data (0-100).

  In step 404, based on the KCMY data, the processing liquid image data (first recording scanning data) to be recorded together with KCMY and the clear ink image data (first recording scanning data) to be recorded subsequently. Data). FIG. 19 is a diagram showing a data generation process performed by the CPU 301 in step 404. In step 1901, KCMY data is acquired. In step 1902, processing liquid data (0-100) and clear ink data (0-100) are generated from the sum of KCMY data (0-100) based on the table shown in FIG. 20. In 1903, data for each scan is acquired.

  The processing liquid data, the clear ink data, and the KCMY data generated in step 404 are quantized to 9 values of 0-9 in 600 dpi pixel units in step 405, and further, according to the pattern shown in FIG. And it is developed into binary print data of 2400 dpi units, which is the print resolution in the main scanning direction. Here, 0-9 in 600 dpi pixel units corresponds to the number of dots in 600 dpi pixels.

  In step 406, the generated recording data is stored in the RAM 303 or a predetermined memory having a buffer function. This data is transmitted to the recording head driver at an appropriate timing.

(Recording operation)
In this embodiment, 4-pass multi-pass printing is performed by the print head 1600 shown in FIG. Hereinafter, multipass recording will be briefly described.

  In multi-pass printing, the print head 1600 thins out image data that can be printed in one main scan according to a mask pattern prepared in advance, and an image is completed in stages by a plurality of main scans. In the fourth embodiment of the present invention, the first recording scan for ejecting ink containing an emulsion having a high Tg is performed in three passes, and the second recording scan for ejecting ink containing an emulsion having a relatively low Tg is performed. Perform in one pass.

  FIG. 21 is a schematic diagram for briefly explaining the multipass printing method. Here, for the sake of simplicity, a case where 3-pass multi-pass printing is performed using an ejection port array 2100 having 12 ejection ports will be described. In the case of 3-pass multi-pass printing, the discharge port array 2100 can be divided into three regions (region 1 to region 3) each including four discharge ports. Reference numerals 2101a to 2101c denote mask patterns addressed to the areas 1 to 3, respectively. Each mask pattern has an area of 4 pixels × 4 pixels in which a print permitting pixel shown in black and a non-printing allowance pixel shown in white are defined. The pixel is complemented. When recording is actually performed, a logical product operation is performed between image data (recording / non-recording data) addressed to each ejection port and a mask pattern, and ejection operation based on the result is performed. The Here, for simplicity, a mask pattern having an area of 4 pixels × 4 pixels is shown, but the actual mask pattern has larger areas both in the main scanning direction and in the sub-scanning direction.

  FIG. 22 is a diagram illustrating a process in which the recording head 1600 applies ink onto the recording medium by multipass recording in the fourth embodiment of the present invention. 22A to 22C, the processing liquid and KCMY ink applied in the first recording scan are recorded in the first to third passes, and the recording medium 2201 is conveyed by 384 nozzles after recording each pass. To do. Then, in FIG. 22D, the clear ink to be applied in the second recording scan is applied, and the image formation in the area 2200d, which is the same area as 2200a to 2200c in which the recording is performed from 1 to 3 passes, is completed. . In the fourth embodiment, the platen portion facing the recording head is provided with a platen heater 1304 as shown in FIG. 13, and the surface of the recording medium 2201 to which ink is not applied in each recording scan is 100 ° C. Thus, recording is performed while heating the recording medium 2201.

  Table 3 summarizes the Tg of the resin fine particles in the combination of inks used in the fourth embodiment, and the qualitative evaluation of the scratch resistance and image quality of the obtained image. In the ink jet recording apparatus, the glass transition temperature Tg1 of the resin particles contained in the treatment liquid and the KCMY ink applied in the first to third passes, which is the preceding first recording scan, is the subsequent second recording scan. It is higher than the glass transition temperature Tg2 of the resin fine particles contained in the clear ink applied in the fourth pass. The difference between Tg1 and Tg2 is preferably 20 ° C. or higher. As described above, according to this embodiment, since the Tg1 of the resin fine particles applied in the preceding pass is relatively high and difficult to melt, the ink applied in the subsequent pass does not melt in the heat fixing of the preceding pass. Does not affect the penetration of For this reason, it is possible to form a good image without deteriorating beading in recording in subsequent passes. Further, an image excellent in scratch resistance can be obtained by the effect of the melted resin particles.

  In this embodiment, it is preferable that the Tg of the resin fine particles contained in the ink is lower than 100 ° C. of the surface temperature of the recording medium heated by the heat fixing device.

Claims (9)

A recording head for applying ink to a recording medium by discharging a first ink containing first resin fine particles and a second ink containing second resin fine particles having a glass transition temperature lower than that of the first resin fine particles And the first recording scan data corresponding to the ink ejected from the recording head in the first recording scan based on the image data corresponding to the image to be recorded, and the first recording Image processing means for generating data for the second recording scan that is subsequently ejected from the recording head in the second recording scan after the scan, and the first recording at the time of the first recording scan. Heating means for heating the recording medium after the ink is applied in the scanning, and heating the recording medium after the ink is applied in the first recording scan during the second recording scan; Recording device Oite,
The image processing means is configured such that the first ink application amount in the first recording scan is larger than the first ink application amount in the second recording scan, and the first ink is applied in the second recording scan. The recording apparatus, wherein the image data is generated so that a second ink application amount is larger than the second ink application amount in the first recording scan.   The recording apparatus according to claim 1, wherein a difference between a glass transition temperature of the first resin fine particles and a glass transition temperature of the second resin fine particles is 20 ° C. or more.   3. The recording according to claim 1, wherein the brightness of the dots formed on the recording medium with the first ink is lower than the brightness of the dots formed on the recording medium with the second ink. apparatus.   The image processing means determines whether the number of dots per predetermined area of the ink containing the second resin fine particles exceeds a threshold value, and the first ink dot is in the same area as the area exceeding the threshold value. In the case where there is no ink, the image data of the ink containing the second resin fine particles in the region is divided into data for the first recording scan and data for the second recording scan. The recording apparatus according to claim 1.   The image processing means preferentially divides the ink having the low lightness of the dots formed on the recording medium among the ink containing the second resin fine particles into the data for the first recording scan. The recording apparatus according to claim 4.   6. The recording apparatus according to claim 4, wherein the image processing unit thins out the data for the first recording scan.   The image processing means determines whether the sum of the number of dots of each ink for each predetermined area exceeds a threshold value, and when there is an area exceeding the threshold value, scanning that performs only heating without discharging ink, The recording apparatus according to claim 1, wherein the recording apparatus is performed after the second recording scan.   The recording apparatus according to claim 7, wherein the predetermined area is a pixel group including at least one pixel. The recording apparatus according to claim 1, wherein the first ink is a color ink, and the second ink is a clear ink.

Images