JP2017114112A - Apparatus ejecting liquid, method for providing medium with processing solution and image creating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of piling phenomenon where foreign substances having an adhesiveness are gradually accumulated on a contacting member in a case where pretreatment solution is applied to successive medium subjected to surface reforming process.SOLUTION: It comprises: pretreatment solution providing means 20 providing pretreatment solution 27 to medium 10; a liquid ejection head 50 ejecting and providing liquid containing coloring material to the medium 10 to which the pretreatment solution 27 has been provided; drying means 3 drying the pretreatment solution; and controlling means which controls volume of the pretreatment solution to be provided by the pretreatment solution providing means 20 at a volume with which hardness measured by nanoindentation method in surface of the medium 10 dried by the drying means 3 is 0.07 GPa or more.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an apparatus for ejecting liquid, a method for applying a treatment liquid to a medium, and an image forming method.

  For example, in a device that discharges liquid using a continuous medium, stable discharge over a long period of time is possible, but there are significant restrictions on the physical properties of the liquid that can be used, but only with a medium that has undergone non-permeation surface modification treatment. In addition, it is required that an osmotic medium can be used. The continuous medium includes what are called roll paper, continuous paper, forms, web media, and the like.

  Therefore, there is a conventional technique that uses a fast drying ink (Patent Document 1) in which a solvent evaporates at a high speed and is dried. In addition, in order to avoid a drop in ejection reliability during long-time operation that occurs when high-speed drying ink is used, printing is performed after surface modification by applying a pretreatment liquid (primer) to the medium (Patent Document) 2) is known.

Japanese Patent Laid-Open No. 05-025417 JP 2010-052284 A JP 2009-256852 A

  By the way, when a pretreatment liquid that is a surface modification treatment liquid is further applied to a medium that has already been coated, due to a mismatch between the original coating material and the pretreatment liquid, a contact member such as a conveyance roller that contacts the medium is used. In some cases, a piling phenomenon in which sticky foreign substances gradually accumulate may occur.

  When a piling phenomenon occurs and foreign matter is transferred from the contact member onto the medium, the print quality is deteriorated.

  However, in addition to the fact that the cause and control factors of the piling phenomenon are not well understood, the time from the start of operation of the device until the manifestation of the pile becomes the number of mileage of the medium depending on the type of medium and the operation status of the device. Since it changes greatly from 10 km to hundreds of km, there is a problem that it is very difficult to deal with.

  The present invention has been made in view of the above problems, and an object of the present invention is to suppress the occurrence of piling as much as possible.

In order to solve the above problems, an apparatus for ejecting a liquid according to the present invention includes:
Means for applying a treatment liquid to the medium;
Drying means for drying the treatment liquid applied to the medium;
Means for applying a liquid containing a coloring material to the medium to which the treatment liquid has been applied;
And a means for controlling the amount of the treatment liquid applied so that the surface hardness of the medium after drying by the drying means is 0.07 GPa or more by the nanoindentation method.

  According to the present invention, occurrence of piling can be suppressed as much as possible.

It is a schematic explanatory drawing of an example of the apparatus which discharges the liquid which concerns on this invention. It is explanatory drawing of a pre-processing means. It is block explanatory drawing of a control means. It is a block explanatory view of a host device constituting the control means. It is block explanatory drawing of the output control apparatus which comprises the control means. It is explanatory drawing with which it uses for description of the measurement of the hardness by a nanoindentation method. It is explanatory drawing of a typical load-displacement curve similarly. It is explanatory drawing of an example of the surface profile of a medium similarly. It is explanatory drawing of an example of the measurement result by the nanoindentation method similarly. It is explanatory drawing with which it uses for description of the relationship of the surface hardness of the medium with respect to the provision amount of a pre-processing liquid, and dry strength. It is a flowchart with which it uses for description of an example of the control by a control means. It is a figure which shows the relationship between hardness and a pile weight. It is a figure which shows the relationship between an elasticity modulus and a pile weight.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an apparatus for discharging a liquid according to the present invention will be described with reference to FIG. FIG. 1 is a schematic explanatory view of the apparatus.

  The apparatus includes a carry-in means 1 for carrying in a continuous medium (hereinafter simply referred to as “medium”) 10, a pre-treatment means 2 for applying a pre-treatment liquid to the medium 10 carried in from the carry-in means 1, and a medium And a pretreatment liquid application post-drying means 3 that dries the pretreatment liquid applied to 10.

  Then, after the pretreatment liquid is applied, the medium 10 that has passed through the drying unit 3 is guided and conveyed to the printing unit 5, and the medium 10 is printed to discharge the liquid containing the coloring material to form an image. A printing unit 5, a drying unit 7 for drying the medium 10, and a discharging unit 9 for discharging the medium 10 are provided.

  As the medium 10, a medium in which a surface modification treatment layer containing at least a water-soluble resin is formed on the surface of the substrate is used.

  The medium 10 is sent out from the original winding roller 11 of the carry-in means 1 and guided by the rollers of the carry-in means 1, the pretreatment means 2, the pretreatment liquid-applied drying means 3, the guide transport means 4, the drying means 7, and the discharge means 9. , And is wound up by the winding roller 91 of the discharge means 9.

  In this medium 10, after the pretreatment liquid is applied by the pretreatment liquid application unit 20 of the pretreatment means 2, the pretreatment liquid is dried by the pretreatment liquid application and drying means 3, and reaches the printing means 5. It is conveyed on the conveyance guide member 59 so as to face the liquid ejection unit 50 and the post-treatment liquid ejection unit 55.

  Then, a required image is formed on the medium 10 by the liquid discharged from the liquid discharge unit 50. Further, post-processing is performed with the post-processing liquid discharged from the post-processing liquid discharge unit 55 as necessary.

  Here, the liquid ejection unit 50 includes, for example, full-line head units 51K, 51C, 51M, 51Y for four colors from the upstream side in the medium conveyance direction (hereinafter referred to as “head unit 51” when the colors are not distinguished). .) Is arranged.

  Each head unit 51 is a means for ejecting a liquid containing a color material, and ejects black K, cyan C, magenta M, and yellow Y liquids to the conveyed medium 10, respectively. The type and number of colors are not limited to this.

  Next, the preprocessing means will be described with reference to FIG. FIG. 2 is an explanatory diagram of the preprocessing means.

  The pretreatment liquid application unit 20 of the pretreatment means 2 applies the stored pretreatment liquid 27 to the surface of the medium 10 carried (conveyed) into the pretreatment means 2 by the carry-in means 1.

  Specifically, the pretreatment liquid application unit 20 first transfers (transfers) the pretreatment liquid 27 to the surface of the coating roller 23 in a thin film state by the stirring (supply) roller 21 and the thinning (transfer) roller 22. .

  Next, the pretreatment liquid application unit 20 presses the application roller 23 against the rotating platen roller 24 and rotates the application roller 23. At this time, the pretreatment liquid application unit 20 applies the pretreatment liquid 27 to the surface of the medium 10 by transporting the medium 10 to the gap between the application roller 23 and the platen roller 24.

  The pretreatment liquid application unit 20 controls the nip pressure (pressure acting on the position where the application roller 23 and the platen roller 24 are in contact) when applying the pretreatment liquid 27 using the pressure adjusting device 25. .

  Accordingly, the pretreatment liquid application unit 20 changes the nip pressure using the pressure adjusting device 25, thereby applying the pretreatment liquid 27 (application amount, film thickness, liquid amount, adhesion amount, dry adhesion amount, etc.). Can be controlled (changed).

  Note that the application amount of the pretreatment liquid 27 can be controlled (changed) by changing the rotation speeds of the application roller 23 and the platen roller 24.

  Next, an example of the pretreatment liquid will be described.

  The pretreatment liquid contains a component that aggregates water-dispersible colorant particles, a water-soluble organic solvent, a penetrating agent, a surfactant, and water, and further contains other components as necessary.

-Components that aggregate water-dispersible colorant particles-
A water-soluble aliphatic organic acid is contained as a component for aggregating the water-dispersible colorant particles.
Here, agglomeration means that water-dispersible colorant particles adsorb and gather together, and can be confirmed by a particle size distribution measuring device.

  When an ionic substance such as a water-soluble aliphatic organic acid is added to the pretreatment liquid, the surface charge is neutralized by adsorption of ions to the surface charge of the water-dispersible colorant. Aggregation is enhanced and aggregation is possible.

  Examples of the method for confirming the aggregation include a method for confirming whether the colorant is instantaneously aggregated when 30 μL of the pretreatment liquid is added with 5 μL of the inkjet ink having a water-dispersible colorant concentration of 5 mass%. .

-Water-soluble organic solvent-
There is no restriction | limiting in particular as a water-soluble organic solvent, According to the objective, it can select suitably. For example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, 1,3-butanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4- Butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, 1,2,4-butanetriol, Polyhydric alcohols such as 1,2,3-butanetriol and petriol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono Polyhydric alcohol alkyl ethers such as chill ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; Nitrogen-containing heterocyclic compounds such as N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, and ε-caprolactam; formamide, N-methylformamide, N, Amides such as N-dimethylformamide; Amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine; dimethyl Sulfur-containing compounds such as sulfoxide, sulfolane, thiodiethanol; propylene carbonate, ethylene carbonate, γ-butyrolactone, and the like. These may be used individually by 1 type and may use 2 or more types together.

  The content of the water-soluble organic solvent is preferably 5% by mass to 80% by mass and more preferably 10% by mass to 20% by mass with respect to the total amount of the pretreatment liquid.

-Penetration agent-
There is no restriction | limiting in particular as a osmotic agent, According to the objective, it can select suitably. For example, alkyl and aryl ethers of polyhydric alcohols such as diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl ether; Examples include lower alcohols such as ethanol and 2-propanol. These may be used individually by 1 type and may use 2 or more types together.

  The content of the penetrant is preferably 0.1% by mass to 20% by mass, and more preferably 0.5% by mass to 10% by mass with respect to the total amount of the pretreatment liquid.

-Surfactant-
Examples of the surfactant include an anionic surfactant, a nonionic surfactant, a cationic surfactant, an amphoteric surfactant, a fluorine surfactant, and a silicone surfactant.

  0.01 mass%-3.0 mass% are preferable with respect to pretreatment liquid whole quantity, and, as for content of surfactant, 0.5 mass%-2 mass% are more preferable. When the content is less than 0.01% by mass, the effect of adding the surfactant may not be obtained. When the content exceeds 3.0% by mass, the permeability to the medium becomes higher than necessary. There may be a decrease in the image density or a show-through.

-Other ingredients-
There is no restriction | limiting in particular as another component, According to the objective, it can select suitably, For example, antiseptic / antifungal agent, a rust preventive agent, a pH adjuster etc. are mentioned.

  Examples of antiseptic / antifungal agents include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, isothiazoline-based compounds, sodium benzoate, and sodium pentachlorophenol.

  The content of the antiseptic / antifungal agent is preferably 0.01% by mass to 3.0% by mass and more preferably 0.5% by mass to 2% by mass with respect to the total amount of the pretreatment liquid.

  Examples of the rust preventive include benzotriazole, acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like.

  0.01 mass%-3.0 mass% are preferable with respect to the said pretreatment liquid whole quantity, and, as for content of a rust preventive agent, 0.5 mass%-2 mass% are more preferable.

  Examples of pH adjusters include hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, and carbonate. Examples thereof include alkali metal carbonates such as lithium, sodium carbonate and potassium carbonate, amines such as diethanolamine and triethanolamine, boric acid, hydrochloric acid, nitric acid, sulfuric acid and acetic acid.

  0.01 mass%-3.0 mass% are preferable with respect to the said pretreatment liquid whole quantity, and, as for content of a pH adjuster, 0.5 mass%-2 mass% are more preferable.

  Next, the post-application liquid drying means 3 will be described with reference to FIG.

  The drying means 3 after applying the pretreatment liquid has heat rollers 31 and 32.

  Thereby, the medium 10 coated (applied) with the pretreatment liquid 27 is transported to the heat rollers 31 and 32 by the transport roller. The heat rollers 31 and 32 are heated to a high temperature of 50 ° C. to 100 ° C., and the medium 10 to which the pretreatment liquid 27 is applied is dried by evaporation of moisture by contact heat transfer from the heat rollers 31 and 32. .

  Next, an outline of the control means of this apparatus will be described with reference to FIGS. FIG. 3 is a block explanatory diagram of the control means, FIG. 4 is a block explanatory diagram of a host device constituting the control means, and FIG. 5 is a block explanatory diagram of an output control apparatus constituting the control means.

  The control unit 700 receives print job data from the host side, processes it, transfers it to the output control apparatus 500, and an output control apparatus that receives print image data from the upper apparatus 600 and performs control related to printing. 500.

  The host device 600 performs RIP (Raster Image Processor) processing that requires processing time. The output control device 500 performs a printing process.

  The host device 600 is a device that performs RIP (Raster Image Processor) processing based on print job data (job data, print data) output from the host device. That is, the host device 600 creates print image data that is bitmap data corresponding to each color based on the print job data.

  The host device 600 creates control information data that is data for controlling the printing operation based on the print job data and the host device information. Here, the control information data refers to printing conditions (printing type, printing type, feeding / discharging information, printing surface order, printing paper size, data size of printing image data, resolution, paper type information, gradation, color information, and the like. Data on the number of pages to be printed).

  Here, as shown in FIG. 4, the host device 600 includes a CPU 601, a ROM 602, a RAM 603, an HDD 604, an external I / F 605, an image data I / F 606, a control information I / F 607, and the like.

  Then, print job data is received from the host device via the external I / F 605, YMCK bitmap data is generated, the generated bitmap data for each color is written to the RAM 603, and the bitmap data for each color is compressed. It is encoded and temporarily stored in the HDD 604.

  Thereafter, when the printing operation is started, the bitmap data of each color is decoded and temporarily written in the RAM 603, the bitmap data of each color is read out, and the print image data of each color is passed through the image data I / F 606. To the output control device 500 side.

  Also, control information data is transmitted / received to / from the output control device 500 via the control information I / F 607 in accordance with the progress of the printing operation.

  As shown in FIG. 5, the output control device 500 includes a main control unit configured by a microcomputer 501A including a CPU 511, a ROM 512, a RAM 513, an I / O, and the like that control the entire device, an image memory, a communication interface, and the like. (System controller) 501 is provided.

  The main control unit 501 sends the print image data to the print control unit 502 in order to form an image on the medium 10 based on the print image data and the print information data transferred from the host device 600.

  The print control unit 502 transfers the print image data received from the main control unit 501 as serial data, and also transfers the transfer clock, latch signal, control signal, and the like necessary for transferring the print data and confirming the transfer. Output to the driver 503.

  Further, the print control unit 502 includes a drive waveform generation unit configured by a D / A converter, a voltage amplifier, a current amplifier, and the like that perform D / A conversion on the pattern data of the common drive waveform stored in the internal ROM. A drive waveform composed of one drive pulse or a plurality of drive pulses is output to the head driver 503.

  The head driver 503 selects a drive pulse that constitutes a drive waveform supplied from the print control unit 502 based on print image data corresponding to one head unit 51 that is serially input, and provides the drive pulse to the pressure generating means. Discharge the liquid. At this time, by selecting part or all of the pulses constituting the driving waveform or all or part of the waveform elements forming the pulse, for example, large dots, medium drops, small drops, etc. Can be categorized.

  The main control unit 501 is connected to the original winding roller 11 of the carry-in means 1, the carry-in means 1, the pretreatment means 2, the pretreatment liquid applying and drying means 3, the guide conveying means 4, the drying means 7, and the discharge via the motor driver 504. The motor group 505 that drives each roller 510 such as each roller of the means 9 and the winding roller 91 of the discharge means 9 is driven and controlled. The driving force need not be applied to all rollers.

  The main control unit 501 gives information on the application amount (application amount) of the pretreatment liquid 27 to the pretreatment liquid application control unit 521. The pretreatment liquid application control unit 521 changes the pressure applied by the pressure adjusting device 25 of the pretreatment liquid application unit 20 so that the pretreatment liquid 27 is applied in the received application amount.

  The main control unit 501 gives information on the drying temperature of the medium 10 to which the pretreatment liquid 27 has been applied to the post-treatment liquid application post-drying control unit 531. The pretreatment liquid application drying controller 531 controls the temperature of the heat rollers 31 and 32 of the pretreatment liquid application drying means 3 so that the received drying temperature is reached.

  The main control unit 501 inputs detection signals from a humidity sensor 508 that detects environmental humidity and a sensor group 506 that includes various other sensors, and inputs and outputs various information and exchanges display information with the operation unit 507. I do.

  Next, the cause of the pyring phenomenon will be described.

  Analysis of the foreign material that had been piled in the apparatus by infrared spectroscopy revealed that it was a coating layer component of the coated paper used. It was also found that the starch component used as a binder in the coat layer of the coated paper was plasticized by the solvent of the pretreatment liquid and adhered to the conveying member in a sticky state.

  As a result, the piling phenomenon that occurs when the surface treatment is further performed by applying the pretreatment liquid to the coated medium is caused by the existing coating layer due to the moisture in the pretreatment liquid and the water-soluble solvent. The binder resin in the (surface modification treatment layer), especially water-soluble resins such as starch and polyvinyl alcohol, soften and progress with printing so that it is worn (dropped) together with the pigment on the surface of the medium and deposited on the contact member It turns out that it is.

  However, if it is estimated how much the existing surface modification layer is worn from the total weight of the pyring substances generated in the actual device, it is predicted that tens to hundreds of angstroms of the surface layer are worn and deposited. It was a result. This is an extremely small amount of wear, and it is very difficult to quantify and predict the wear state by analyzing the existing surface modification layer itself.

  Next, control of the application amount of the pretreatment liquid in the present embodiment will be described.

  In this embodiment, the application amount of the treatment liquid 27 applied to the medium 10 is set to an amount such that the surface hardness by the nanoindentation method of the medium 10 after the treatment liquid 27 is dried is 0.07 GPa or more.

  In this case, it is preferable that the elastic modulus of the medium 10 after the treatment liquid 27 is dried is 4 GPa or more by the nanoindentation method.

  Furthermore, the surface hardness and the elastic modulus are preferably values measured at a depth of 500 nm from the outermost layer of the medium 10.

  The surface hardness of the medium 10 is determined by measurement by a nanoindentation method. This measurement can be performed using, for example, a nanoindenter (TI 950 TriboIndenter manufactured by Hystron).

  Here, the measurement of hardness and elastic modulus by the nanoindentation method will be described with reference to FIG. FIG. 6 is a schematic explanatory diagram for explaining an example of a measurement method for measuring hardness and elastic modulus by the nanoindentation method.

  The hardness measurement by the nanoindentation method is a method of calculating the plastic deformation hardness from the measured value by measuring the relationship between the load and the indentation depth (displacement amount) while pushing a minute diamond indenter into the thin layer.

  Specifically, as shown in FIG. 6, the medium 10 is obtained by forming a coating layer 10 </ b> B as a surface modification treatment layer containing at least a water-soluble resin on the surface of the base body 10 </ b> A. By applying the pretreatment liquid 27 and drying, a pretreatment liquid layer (referred to as a pretreatment layer) 27A is formed on the coat layer 20B.

  Accordingly, the displacement amount of the outermost surface of the medium 10 is measured with nanometer accuracy while applying a load of μN order using the transducer 131 and the diamond Berkovich indenter 132 whose tip shape is an equilateral triangle.

  FIG. 7 shows a typical load-displacement curve obtained when the hardness and elastic modulus are measured by the nanoindentation method.

  Next, calculation of hardness (hardness) will be described with reference to FIG. FIG. 8 is an explanatory diagram for explaining the surface profile of the medium when a load in which the indenter is brought into contact with the medium as the sample is applied and when the load is removed by separating the indenter.

  Here, the surface hardness H of the medium 10 by the nanoindentation method can be obtained from the following equation (1).

  In equation (1), Pmax is the maximum load applied to the indenter, and A is the contact projection area between the indenter and the sample (medium) at that time.

  The contact projection area A can be expressed by the following equation (2) using hc in FIG.

  Here, as shown in FIG. 8, hc becomes shallower than the entire indentation depth h due to the elastic dent on the peripheral surface of the contact point, and is expressed by the following equation (3).

  Here, hs is the amount of indentation due to elasticity, and is expressed by the following equation (4) from the gradient of the load curve after the indenter 132 is pushed (gradient S in FIG. 7) and the shape of the indenter.

  Here, ε is a constant related to the shape of the indenter 132, and is 0.75 in the Berkovich indenter.

  The composite elastic modulus Er is obtained from the following (5).

  Hardness and elastic modulus can be measured using such a measuring device.

The measurement conditions are as follows.
Measuring instrument: (TI 950 TriboIndenter manufactured by Hysitron)
Measuring indenter: Diamond Berkovich indenter with an equilateral triangular tip Measurement environment: 23 ° C., 60% RH
Measurement sample: The medium is cut into a size of 1 cm × 1 cm and fixed on a SUS plate having a thickness of 2 mm. Indentation speed: 20 nm / s

  In addition, measurement measured 4 points | pieces at random for each sample, and made the average value the hardness (hardness) measured by the nanoindentation method, and the elasticity modulus.

  Conventionally, there are various methods for measuring the surface hardness of a substance, such as the Pickers hardness test method, but there are problems such as excessive load and excessive indentation depth.

  In particular, it is very difficult to accurately measure the surface hardness of a substance that is soft as a whole, such as coated paper, by a method other than nanoindentation. In addition, since it is thought that wear of tens to hundreds of angstroms of the surface of the coating layer accumulates for a long time, it is necessary to accurately measure only the physical properties of the very top surface in order to understand the mechanism. .

  The generation mechanism of the pile to be suppressed by the present invention can be regarded as an adhesive wear phenomenon, and can be considered as follows.

  That is, generally, the adhesive wear phenomenon that occurs when a hard object and a soft object come into contact with each other is caused by fusing the surface of a soft substance to the surface of a hard substance, or by scuffing a soft substance.

  Here, the hard member is a member that generates a pile due to contact with the printing surface (image forming surface) of the medium inside the apparatus, that is, a contact member typified by a conveyance roller. It becomes the surface of the medium 10 after being applied and dried.

  Although the roller used for the conveyance path of the medium 10 has been subjected to polishing processing or the like, it has unevenness of several μm level, and the medium 10 is supported by a convex portion on a micro level, and wear when contacted. Work as a contact point.

  Based on the wear theory, at this time, the lower the surface hardness of the medium 10, the higher the adhesive bondability with the contact member, and the more easily the wear particles are generated when the shear stress due to the digging of the convex portion is applied. In addition, as the viscosity of the surface of the medium 10 is higher, the energy generated when digging up by the convex contact point of the contact member is more easily spent on plastic deformation of the surface, and wear powder is more easily torn off from the surface.

  Further, not only the surface hardness and viscosity of the medium 10 but also the surface roughness of the member on the hard side that comes into contact is an important factor.

  The convex part of the roller, which is a contact member, acts as a contact point for wear when contacting the medium 10, but the larger this irregularity, the easier it is for the convex part to pierce the surface of the surface modification treatment layer. The surface digging action when the phenomenon occurs, that is, scuffing is promoted.

  The medium 10 is an elastic body, and when viewed microscopically, the medium 10 is always conveyed with a microscopic vibration under a constant tension at the time of conveyance, and the contact point always moves so as to be rubbed. Adhesive wear phenomenon always occurs in the vicinity of the point, and the outermost surface physical property of the surface modification layer of the medium 10 becomes a major factor of wear phenomenon, that is, the pyring phenomenon.

  Therefore, by controlling the surface properties of the medium 10 within the range of the present invention, it is possible to prevent the occurrence of pyring.

  In addition, when the physical properties of the coat layer surface during the operation of the apparatus do not fall within the scope of the present invention, it can be determined that the medium and the operating conditions cause the pile without performing the actual operation of several tens or hundreds of kilometers. Further, based on this result, it is possible to set and operate conditions under which no piling occurs using a method as described later.

  In general, the coating layer (surface modification layer) of offset paper varies depending on the type of coated paper, but the grade called A2 coat has a thickness of about 10 μm. The thickness of the coated paper in which piling occurs is the same as that of the coated paper in which piling does not occur.

On the other hand, the amount of pile generated when 100 km of paper was passed was around 0.1 g per 25 cm ² area of the contact member. When converted from the number of contact members (rollers) in the apparatus and the width of the sheet passing, the calculation is such that 0.001 μm (= 1 nm) of the surface layer is scraped.

  Therefore, the measurement depth of the physical properties of the coating layer necessary for determining the occurrence of piling was examined.

  FIG. 9 shows the results of measuring the hardness of a coated paper that does not generate a pile and a paper that generates a pile when traveling 100 km by a nanoindentation method at a depth of 500 nm.

  As a result, it was found that there is a clear difference in the load curve and the unload curve between the coated paper where no piling occurs and the coated paper where the piling occurs.

  When an excess pretreatment liquid is applied to the coated layer of the coated paper and dried, the strength of the coated layer will decrease compared to the case of normal coating amount. It was also confirmed that the amount recovered was as much as possible.

  As shown in FIG. 10, it is found that the strength reduction of the coating layer of the medium occurs with the application and drying of the pretreatment liquid and depends on the coating amount (application amount) and the drying strength.

  Therefore, the occurrence of piling can be suppressed by adjusting (controlling) the application amount of the pretreatment liquid.

  That is, when the surface hardness of the medium is reduced, it is possible to prevent the occurrence of piling by reducing the amount of pretreatment liquid applied.

  Further, by increasing the dry strength, it is possible to increase the surface hardness and prevent the occurrence of piling. The drying strength is a value defined by the drying temperature and the drying time.

  At this time, the drying strength may be adjusted by increasing the drying temperature or decreasing the linear speed of paper passing to increase the passage time (drying time) of the drying means 3.

  Next, an example of control by the control means will be described with reference to the flowchart of FIG.

  Here, the medium 10 is carried in by the carrying-in means 1, the pretreatment liquid 27 is applied to the medium 10 by the pretreatment means 2, and the pretreatment liquid 27 is dried by the drying means 3 after applying the pretreatment liquid.

  Thereafter, before the apparatus is temporarily stopped and the intended printing (image formation) is started, the surface physical properties of the medium 10 are measured to determine whether or not the physical property values are the required values (determination OK). .

  Here, when the determination is OK, the printing unit 5 forms an image as it is, and the object to be processed which is the medium 10 on which the image is formed is discharged to the discharge unit 9.

  On the other hand, when the determination is not OK, it is determined whether or not adjustment is possible.

  If adjustment is possible, the output of the heat rollers 31 and 32 of the drying means 3 after applying the pretreatment liquid is adjusted, or the linear velocity of the medium 10 is changed to return to the process of applying the pretreatment liquid 27. .

  On the other hand, if it is not adjustable, the apparatus is stopped and an alarm is notified.

  Specifically, before starting target printing, print a test chart, read it with a scanner, etc., print head heads with shading correction, print and check the test chart again, and then start target printing . At this time, the hardness of the medium 10 (for example, coated paper) is also checked, and the target printing is started after the temperature of the drying means is optimized. Here, if the hardness (hardness) of the coating layer does not exceed the specified value even if parameters such as the drying temperature are set to the limit values, an alarm is issued to notify the risk, and the operator is left to judge. .

  In this embodiment, by inputting the physical properties of the medium 10 to be used (for example, physical properties of paper material, paper thickness, basis weight) to the host device 600, the permeability when printing is calculated, and the like The amount of treatment liquid applied is calculated. Then, the calculated pretreatment liquid application amount information is provided as control information (print information data) from the host device 600 to the main control unit 501 of the output control device 500.

  The main control unit 501 gives the pretreatment liquid application amount information to the pretreatment liquid application control unit 521, so that the pretreatment liquid application control unit 521 sets the pretreatment liquid application amount to the nip pressure of the pretreatment liquid application unit 20. The pressure control device 25 is converted and controlled to obtain the nip pressure.

  As a result, the pretreatment liquid 27 is applied to the medium 10 by the pretreatment liquid application unit 20 in the specified application amount. As described above, the applied amount at this time is an amount such that the surface hardness by the nanoindentation method of the medium 10 after the pretreatment liquid 27 applied with the medium 10 is dried is 0.07 GPa or more.

  Thereby, generation | occurrence | production of piling can be suppressed as much as possible.

  Note that the amount of pretreatment liquid applied is stored and held in advance in the storage unit included in the main control unit 501 or the output control device 500 for each type of medium, and the type of the medium 10 is designated. It is also possible to read the application amount of the pretreatment liquid stored and held and control the pretreatment liquid application unit 20 so as to obtain the application amount.

  In addition, information on permeability for each type of medium is stored and held in advance in a storage unit included in the main control unit 501 or the output control device 500, and the type of the medium 10 is designated. It is also possible to read information on permeability and calculate the amount of pretreatment liquid applied from the numerical value of permeability.

  Further, the application amount may be adjusted by the rotation speed of the application roller 23. In this case, the pretreatment liquid application control unit 521 is configured to be able to control the rotation speed of the platen roller 24 of the pretreatment liquid application unit 20, and the pretreatment liquid application control unit 521 is information on the applied amount of the pretreatment liquid. Accordingly, the rotational speed of the platen roller 24 is controlled.

  In addition to the information on permeability, the amount of pretreatment liquid applied can be determined according to other physical properties as long as the physical properties are related to the cohesiveness of the liquid on the medium.

  In this way, the amount of the treatment liquid applied is controlled to an amount such that the surface hardness of the medium after the treatment liquid is dried by the nanoindentation method is 0.07 GPa or more.

  Therefore, in the method of applying the treatment liquid to the medium according to the present invention, the treatment liquid is applied in such an amount that the surface hardness of the medium after the treatment liquid is dried by the nanoindentation method is 0.07 GPa or more. In the image forming method according to the present invention, an image is formed by applying a liquid to a medium having a surface hardness of 0.07 GPa or more by a nanoindentation method after the treatment liquid is dried.

  Next, specific examples of the present invention will be described.

(Preparation Example 1)
<Preparation of pretreatment liquid>
The following composition was stirred for 1 hour and mixed uniformly. The remaining amount of water was added to the obtained mixed solution so as to be 100% by mass in total and stirred for 1 hour. Subsequently, pressure filtration was performed with a cellulose acetate membrane filter having an average pore diameter of 0.8 μm to remove coarse particles, thereby preparing a pretreatment liquid A1.

[Composition of pretreatment liquid]
・ 1,3-butanediol: 10% by mass
・ L-lactic acid: 15% by mass
-Fluorosurfactant (Polyfox PF-151N, manufactured by Daikin Industries) ... 0.05% by mass
-Antifoaming agent (silicone KM-72F, manufactured by Shin-Etsu Silicone) 0.05% by mass
・ 2-Amino-2-ethyl-1,3-propanediol ... 0.1% by mass
・ N, N-diethylethanolamine: 23.42% by mass
・ Calcium lactate: 5% by mass
Surfactant (RF-O-polyoxyethylene ether, manufactured by Neos, Footage 251) ... 0.1% by mass
-Polyether-modified silicone compound (KF-643, manufactured by Shin-Etsu Chemical Co., Ltd.) ... 1% by mass
Antifungal agent (1,2-benzisothiazolin-3-one dipropylene glycol 20% aqueous solution, manufactured by Arch Chemicals Japan, Proxel GXL) 0.05% by mass
・ 1,2,3-benzotriazole ... 0.1% by mass
・ Ion exchange water

(Preparation Example 2)
<Preparation of cyan pigment dispersion>
After sufficiently replacing the inside of the 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas introduction tube, reflux tube, and dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate Then, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) and 0.4 g of mercaptoethanol were charged and heated to 65 ° C.

  Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxyethyl methacrylate, styrene macromer (trade name: AS-6, manufactured by Toagosei Co., Ltd.) A mixed solution of 36.0 g, mercaptoethanol 3.6 g, azobisdimethylvaleronitrile 2.4 g, and methyl ethyl ketone 18 g was dropped into the flask over 2.5 hours.

  After completion of dropping, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours.

  After aging at 65 ° C. for 1 hour, 0.8 g of azobisdimethylvaleronitrile was added, and further aging was performed for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution having a concentration of 50% by mass.

  A part of the obtained polymer solution was dried and measured by gel permeation chromatography (standard: polystyrene, solvent: tetrahydrofuran). The weight average molecular weight was 15,000.

  Next, 28 g of the obtained polymer solution, 26 g of copper phthalocyanine pigment, 13.6 g of 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 30 g of ion-exchanged water were sufficiently stirred.

  Thereafter, the mixture was kneaded 20 times using a three-roll mill (manufactured by Noritake Company, trade name: NR-84A). The obtained paste was put into 200 g of ion-exchanged water and stirred sufficiently, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain 160 g of a cyan pigment-containing polymer fine particle dispersion having a solid content of 20.0% by mass. It was.

  When the volume average particle diameter of the obtained cyan pigment-containing polymer fine particles was measured with Microtrac UPA (manufactured by Microtrad), the volume average average particle diameter was 98 nm.

(Preparation Example 3)
<Preparation of magenta pigment dispersion>
A magenta pigment-containing polymer fine particle dispersion was obtained in the same manner as in the preparation of the cyan dispersion except that the copper phthalocyanine pigment of the cyan dispersion was changed to Pigment Pigment Red 122.

  When the volume average particle size of the obtained magenta pigment-containing polymer fine particles was measured with Microtrac UPA (manufactured by Microtrad), the volume average particle size was 124 nm.

(Preparation Example 4)
<Preparation of yellow pigment dispersion>
A yellow pigment-containing polymer fine particle dispersion was obtained in the same manner as in the preparation of the cyan dispersion except that the copper phthalocyanine pigment of the cyan dispersion was changed to Pigment Pigment Yellow 74.

  The volume average particle diameter of the obtained yellow pigment-containing polymer fine particles was measured by Microtrac UPA (manufactured by Microtrad) and found to be 78 nm.

(Preparation Example 4)
<Preparation of black pigment dispersion>
A black pigment-containing polymer fine particle dispersion was obtained in the same manner as in the preparation of the cyan dispersion except that the copper phthalocyanine pigment of the cyan dispersion was changed to carbon black (manufactured by Degussa, FW100).

  The volume average particle diameter of the obtained black pigment-containing polymer fine particles was measured by Microtrac UPA (manufactured by Microtrad) and found to be 110 nm.

(Production Examples 1-4)
-Manufacture of ink-
1,3-butanediol, glycerin, anionic fluorine-based surfactant (manufactured by OMNOVA, Polyfox PF-151N), octanediol and other components shown in Table 1 are mixed and stirred for 1 hour to mix uniformly. To do.

  The cyan, magenta, yellow, and black pigment dispersions were added to the mixed solution, and the remaining amount of water was added so that the total amount was 100% by mass, followed by stirring for 1 hour.

  Thereafter, pressure filtration was performed with a cellulose acetate membrane filter having an average pore diameter of 0.8 μm to remove coarse particles, and inks 1 to 4 were produced.

(Examples 1-5)
<Image formation>
As shown in Table 2, the pretreatment liquid A1 was pretreated on a roll-like paper by a roller coating method while changing the application amount of the pretreatment liquid, and a paper passing test of 100 km was performed. The drying conditions at this time are as shown in Table 2.

  Also, the inks used in Table 1 were used for paper passing.

  The roller deposit after passing 100 km was weighed. The results are shown in Table 2.

In Table 2, the pretreatment applied the pretreatment liquid, and the adhesion amount represents the adhesion amount of the pretreatment liquid.
Drying indicates the degree of drying of the pretreatment liquid. The standard is 80 ° C. for 3 seconds, and the strength is 100 ° C. for 5 seconds.
The test run indicates the number of media travel distances for checking the occurrence of the pile.
The pile weight is obtained by weighing the foreign matter accumulated on the contact member per 25 cm ² .
The roller Ra indicates the Ra on the roller surface with which the medium surface on the pretreatment liquid application side contacts after drying the pretreatment liquid.
The in-device pile weight is calculated from the weight of the foreign matter deposited on all contact members.

  From FIG. 12 showing the relationship between the amount of pile and the hardness, the amount of treatment liquid applied is controlled to an amount such that the surface hardness of the medium after the treatment liquid is dried by the nanoindentation method is 0.07 GPa or more. It can be seen that piling can be suppressed.

  From FIG. 13 showing the relationship between the amount of the pile and the elastic modulus, it is possible to suppress the occurrence of the pile because the elastic modulus of the medium after the treatment liquid is dried is 4 GPa or more by the nanoindentation method. Further, the surface hardness and the elastic modulus are preferably values measured at a depth of 500 nm from the outermost surface of the medium in a state where the treatment liquid is applied.

  Further, from the results of Example 3 and the like, the surface roughness Ra of the member (here, the roller) that contacts the surface of the medium 10 on which the pretreatment liquid 27 is applied is 2 μm or less in order to suppress the occurrence of piling. preferable.

2 Pretreatment means 3 Drying means after application of pretreatment liquid 5 Printing means 10 Continuous medium 20 Pretreatment liquid application section 27 Pretreatment liquid 50 Liquid discharge unit 500 Output control device 600 Host device

Claims (9)

Means for applying a treatment liquid to the medium;
Drying means for drying the treatment liquid applied to the medium;
Means for applying a liquid containing a coloring material to the medium to which the treatment liquid has been applied;
And a means for controlling the amount of the treatment liquid applied to an amount such that the surface hardness of the medium after drying by the drying means is 0.07 GPa or more by the nanoindentation method. A device that discharges. The apparatus for discharging a liquid according to claim 1, wherein the elasticity of the medium after the treatment liquid is dried is 4 GPa or more by a nanoindentation method. The liquid according to claim 2, wherein the surface hardness and the elastic modulus are values measured at a depth of 500 nm from the outermost surface of the medium in a state where the treatment liquid is applied. Device to do. 4. The liquid according to claim 1, wherein the medium has a surface modification treatment layer containing at least a water-soluble resin on a surface side to which the treatment liquid is applied. apparatus. The apparatus for discharging a liquid according to claim 1, wherein the treatment liquid contains at least one of water and a water-soluble solvent. A member in contact with the surface of the medium on which the treatment liquid is applied;
6. The apparatus for discharging a liquid according to claim 1, wherein a surface roughness Ra of the contacting member is 2 [mu] m or less. 6. The apparatus for discharging a liquid according to claim 1, wherein a drying strength when the processing liquid is dried by the drying unit is adjusted according to a surface hardness of the medium. A method of applying a treatment liquid to a medium to which a liquid containing a coloring material is applied before applying the liquid,
A method for applying a treatment liquid to a medium, comprising applying the treatment liquid in an amount such that the surface hardness of the medium after the treatment liquid is dried by nanoindentation is 0.07 GPa or more. An image forming method of applying a treatment liquid to a medium, drying the treatment liquid, and then applying a liquid containing a coloring material to the medium,
An image forming method, wherein the liquid is applied to the medium having a surface hardness of 0.07 GPa or more by a nanoindentation method after the treatment liquid is dried.

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