JP2006132012A - Method for producing coated paper and apparatus for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain coated paper capable of exhibiting printability especially severely required as the coated paper in recent years, while produced by high-speed papermaking at a papermaking speed of not less than 1,300 m/min. <P>SOLUTION: In a method for producing the coated paper, successive processes (1) to (6) are sequentially incorporated into an on-machine system as follows: (1) a process for conducting the paparmaking with a gap-type twin-wire former which forms a paper layer by ejecting paper stock from a head box into a gap between two of wires each forming a loop; (2) a process for forming wet paper with a dehydration means comprising suction (forming) rolls and/or blades in a wire part; (3) a process for drying the wet paper; (4) a process for nipping the wet paper with a pre-calender 50 formed by a combination of a metal roll 51, an elastic roll 52, etc.; (5) a process 61 for coating the paper with an aqueous coating solution containing an adhesive and a pigment as main components; and (6) a process for subjecting the paper to flattening treatment with a heat calender 70 which has at least two nips, is structured to have two or more stages, and comprises a combination of metal rolls and elastic rolls. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a manufacturing method and manufacturing equipment for coated paper.
In particular, the present invention uses a paper machine having a gap type twin wire former, and performs on-machine coating and surface finishing of the paint at a high speed of 1300 m / min or higher, more preferably 1400 m / min or higher. Thus, the present invention relates to a coated paper manufacturing method and manufacturing equipment that can efficiently produce high-quality coated paper.

  In recent years, paper machines have been increasing in width and speed in order to save labor and reduce manufacturing costs. In particular, in the wire part, the adoption of an on-top former and a shift to a twin wire former are remarkable in order to improve the deterioration of the front / back difference and the deterioration of formation due to the increase in speed from the long net former.

  In particular, there is a tendency to employ many gap type gap formers in which a paper jet ejected from a head box is immediately sandwiched between two wires. This gap former has the advantage that there is very little difference between the front and back because the stock is ejected upward and dehydrated from both sides.

  Although it is a gap former having such a basic advantage, in the case of producing coated paper at a high speed, various problems become apparent, and the improvement with the wire part or the gap former alone cannot be solved.

  In other words, in the gap former, the paper jet that has exited the head box is immediately subjected to strong dehydration on both wire surfaces. The higher the speed, the more the fine fibers on the surface of the wet paper that come into contact with the wire come off. There are also disadvantages such as a decrease in the retention of the raw material and a difference in the properties of the front and back surfaces depending on the difference in the dehydration ratio from both wire surfaces. Therefore, when making high-speed paper using a base paper manufactured with a paper machine having this gap former for the wire part, it is unsuitable for high-definition printing applications. However, the production of the product has caused problems such as the smoothness of the surface of the product, the deterioration of gloss after printing, and the difference between the front and back.

  Also, in wire part dewatering, measures have been tried to give microweaving to the wet paper layer with the pulse force of the dewatering blade, promote fiber dispersion, improve the formation (sheet formation), and improve printability. However, the fine pulsing force inside the wet paper causes the fine fibers inside the wet paper to slip out, resulting in a decrease in yield, and the entanglement between the fibers inside the wet paper is reduced. (Internal bond) is reduced, causing delamination during printing and a blister problem in the drying process after printing.

  In response to the recent trend of visualization and multimedia, printed materials that have been widely used as media for publishing, advertising, publicity, etc., have rapidly increased the need for higher quality such as visualization and colorization. is doing. With such changes in user requirements, the switch from conventional non-coated printing paper to printing coated paper is increasing, and the demand for printing coated paper is rapidly increasing.

  In addition, from the printing process, quality requirements for printing paper handling and stability on the printing press, which lead to improved workability and efficiency, are becoming increasingly severe.

  Thus, there is a strong demand to find a method for producing a coated paper for printing having more excellent printing characteristics while taking advantage of the high-speed operation characteristics of the gap former.

  In response to these quality requirements, a thermal soft calendar capable of obtaining high smoothness and gloss has been attracting attention in recent years. This thermal soft calendar is a method in which a metal roll is usually heated to 100 ° C. or higher to pressurize and smoothen the coated paper. This method has an advantage that a high surface smoothness and printing gloss can be obtained with a small number of nips as compared with a conventional super calender, and the product stiffness can be maintained at a relatively high value. While passing through a nip consisting of a heated metal roll and an elastic roll, a latex or other thermoplastic material used as an adhesive in the coating layer is plasticized by high temperature and pressure, and the pigment in the coating layer This is because the surface of the coating layer can be smoothed by effectively orienting the film, and the inner base paper layer can be kept relatively bulky with a small number of nips.

  However, in the advent of higher-speed paper machines that exceed 1300 m / min, even if the thermal soft calendar is used, sufficient flattening cannot be performed, and flattening by a method of increasing the number of stages or stacks. However, there is a problem that the capital investment cost becomes enormous.

Further, although known from the technology of Patent Document 1 using a thermal soft calendar, it is difficult to say that it is a sufficient flattening process.
Japanese Patent Laid-Open No. 11-100807

  Therefore, the main problem of the present invention is to obtain a coated paper exhibiting the printability required for particularly severe coated paper in recent years, even if the papermaking speed is 1300 m / min or more.

  The present inventor firstly, in a coated paper manufacturing method comprising a combination of a papermaking facility using a gap former and a thermal soft calender, a raw material in which dehydration at the wire part immediately after the gap former is discharged from the head box. By using a forming (suction) roll gently, the fine fibers are kept in the wet paper, and / or by dehydrating with a blade using a dehydrating means to prevent a decrease in the internal bond. Then, by flattening the surface of the base paper by nipping with a pre-calender with a combination of a metal roll and an elastic roll, it becomes possible to improve the flatness of the base paper surface without increasing the tension. , Suppressing the occurrence of coating unevenness in the coating liquid, and thirdly, applying an aqueous coating liquid mainly composed of an adhesive and a pigment And fourth, by performing the subsequent flattening process with a thermal soft calender, the paper making speed is higher than 1300 m / min, especially by using the pre-calender before coating and the thermal soft calender after coating. It is found that it is possible to obtain coated paper exhibiting the printability required for conventional coated paper even when it is papermaking, and it is possible to obtain excellent operational stability, thereby completing the present invention. It came to.

That is, the present invention that has solved the above problems is as follows.
<Invention of Claim 1>
A method for producing coated paper, wherein the following continuous steps are incorporated in order in an on-machine.
A paper making process using a gap type twin wire former that forms a paper layer by ejecting paper from the head box between two looped wires.
Forming a wet paper with a dewatering means using a suction (forming) roll and / or a blade in the wire part;
Drying wet paper,
Nip process with pre-calendar,
Applying an aqueous coating liquid mainly composed of an adhesive and a pigment;
A step of flattening with a thermal calendar composed of a combination of metal rolls and elastic rolls configured in a plurality of stages having at least two nips.

<Invention of Claim 2>
The method for producing a coated paper according to claim 1, wherein the papermaking speed is 1300 m / min or more.

<Invention of Claim 3>
The pre-calender is a combination of a metal roll and an elastic roll, the surface roughness (JIS B 0601) of the metal roll is 2.5 to 4.5 μm, and the Shore D hardness of the elastic roll is 90 or more. Item 3. A method for producing a coated paper according to Item 1 or 2.

<Invention of Claim 4>
The manufacturing method of the coated paper of any one of Claims 1-3 whose nip pressure in a pre-calender is 5 KN / m-50 KN / m.

<Invention of Claim 5>
The method for producing a coated paper according to any one of claims 1 to 4, wherein the step of applying the aqueous coating liquid is performed by blade coating.

<Invention of Claim 6>
The manufacturing method of the coated paper of any one of Claims 1-5 which makes the surface temperature of the metal roll of a heat calendar the heating temperature of 130 degreeC or more.

<Invention of Claim 7>
A coated paper manufacturing facility in which the following continuous means are incorporated in order in an on-machine.
Means for paper making with a gap type twin wire former that forms a paper layer by ejecting paper from the head box between two looped wires,
Means for forming wet paper with a dewatering means by suction (forming) rolls and / or blades in the wire part;
Means for drying wet paper,
Pre-calendar that nips with a combination of metal roll and elastic roll,
Means for applying an aqueous coating liquid mainly composed of an adhesive and a pigment;
Means for flattening with a thermal calender composed of a combination of metal rolls and elastic rolls configured in multiple stages having at least two nips.

  With the method for producing coated paper according to the present invention, it is possible to ensure extremely good operability when performing high-speed papermaking of 1300 m / min or more (design speed of 1800 m / min or more), and mainly contain an adhesive and a pigment. By coating the aqueous coating liquid with a blade, coated paper excellent in gloss, smoothness, and printability can be produced with a consistent papermaking apparatus (online machine) from papermaking raw materials to products.

The present invention is, for example, coated paper having a base paper weight of 28 to 80 g / m ² (particularly 39 to 48 g / m ² ) and a product paper weight of 40 to 105 g / m ² (particularly 54 to 64 g / m ² ). Alternatively, it is intended to produce finely coated paper continuously and consistently from papermaking to winding at a papermaking speed of 1300 m / min or higher, for example, an average papermaking speed of 1600 m / min and a designed papermaking speed of 1800 m / min. Yes.

First, an overall outline of an embodiment of the present invention will be described with reference to FIGS.
A paper machine for making paper with a gap type twin wire former 10 that forms a paper layer by ejecting a paper material J from a head box 3 between two looped wires (between the first wire 1 and the second wire 2). Is installed. In the wire part, the paper material J is discharged between the wires between the suction (forming) roll 4A and the opposite roll 4B to form a paper layer. The paper layer is composed of the suction (forming) roll 4A, the blade 5, While passing through the suction couch roll 6, the suction box 7, etc., it is dehydrated to about 20%, for example.

  Here, as the dehydrating mechanism, the combination of the roll means and the blade dewatering means is shown in the illustrated example, but preferably both, but only one is possible.

  The head box 3 is installed upward in a state inclined vertically or downstream, and as shown in an enlarged view in FIG. 6, when the paper discharge direction line is a horizontal line, the discharge angle θ is 50 degrees to 90 degrees. Is desirable. Under the high-speed papermaking intended by the present invention, it is desirable that the head box is an upward head in which the influence of the fiber weight is small in terms of formation, Z-axis strength, front / back difference, fiber orientation angle, and the like. In the gap type twin wire former, if the head box is horizontal, it is difficult to obtain the desired characteristics under high-speed papermaking.

The paper layer in the wire part is transferred to the press part and further dewatered. In the press part in the embodiment, each of the first press 21 and the second press 22 has shoe presses 21a and 22a, and the paper layer is nipped straight in order to eliminate open draw and prevent paper breakage. It is as. In contrast to the double felt first press 21, the second press 22 employs a belt on the bottom side to improve dehydration and prevent rewetting. When the basis weight is as high as 60 g / m ² or more and the dewatering amount is increased, double felt is desirable.

  The wet paper having a water content of about 50% that has passed through the press part moves to the pre-dryer part and is dried. The illustrated pre-dryer part is a single deck dryer of a no-open draw type, and has an appropriate number of rolls including a heating roll 31 on the upper side and a vacuum roll 32 on the lower side. In the initial stage of the dryer, it is desirable to finely divide the group for draw adjustment, and to install a suction box 33 for improving paper passing performance and sheet running performance.

  The paper sheet dried in the pre-dryer part is coated on both sides with a sizing agent such as starch and a pigment coating solution in a size press 40 by film transfer with the after-dryer part. As the size press 40, a gate roll coater 40A or the like may be used in addition to the illustrated rod metering size press coater. After applying the sizing agent and the pigment coating liquid, it is desirable to install an air turn bar 41 and an auxiliary drying device 42 using infrared rays in advance so that surface contamination does not occur in the after dryer.

  In the illustrated single deck after-dryer part, the sizing agent and the pigment coating solution are dried.

  Thereafter, an aqueous coating liquid mainly composed of an adhesive and a pigment (such as clay) is applied at the coater part. In this case, since a coated paper having high smoothness and glossiness is required under the condition of a papermaking speed of 1300 m / min or more, a coating paper that can be obtained using blade coating as an aqueous coating solution is required. Desirable in quality.

  However, prior to blade coating of the aqueous coating liquid, it is desirable to smooth the surface to which the sizing agent has been applied with the pre-calender 50 in order to ensure higher smoothness. The pre-calender 50 of the embodiment may be a metal roll at the top and bottom, but is preferably a soft calender. For example, the upper side is a metal roll 51 and the lower side is an elastic roll 52 as shown in the figure. The surface of the base paper can be flattened by the treatment with the pre-calender 50, and the surface of the base paper can be flattened without increasing the tension of the paper by not requiring excessive flattening treatment with the subsequent thermal soft calender. This makes it possible to improve the properties of the coating liquid and to obtain a bulky coated paper, and to suppress the occurrence of coating unevenness of the coating liquid by treating the surface of the base paper with a flattening treatment.

The surface roughness (JIS B 0601) of the metal roll in the pre-calender 50 is preferably 2.5 to 4.5 μm, and the Shore D hardness of the elastic roll is desirably 90 or more.
Further, the nip pressure in the pre-calender is preferably 10 KN / m to 40 KN / m. When the nip pressure is less than 5 KN / m, the smoothness of the base paper is difficult to obtain. On the other hand, when the nip pressure exceeds 50 KN / m, the tightness of the paper becomes excessive.
If necessary, the metal roll of the pre-calendar 50 is one that heats by circulating a heat medium such as oil, as in the configuration of the thermal calendar described later, and an internal heating device that uses an electromagnetic induction function that can control the division temperature in the width direction. Those equipped, those equipped with an external heating device by electromagnetic induction capable of controlling the division temperature in the roll width direction, and those equipped with cooling equipment capable of controlling the cooling temperature in the roll width direction can be employed.

  In the coater part, the first coating machine 61 on the upper surface, the gas type air dryer 62, the first canvas dryer 63, the second coating machine 64 on the lower surface, the gas type air dryer 66, and the second canvas dryer 67 are sequentially arranged. is set up. Desirably, in order to prevent uneven drying in the width direction after the first coating machine 61, a first infrared drying device 68 capable of controlling the temperature in the width direction is provided. In addition, it is desirable to provide a second infrared drying device 69 whose temperature can be controlled in the width direction, mainly for adjusting the moisture content, after the second coating machine 64. If necessary, it is also possible to provide a third infrared drying device 69A downstream of the gas air dryer 66.

In the first coating machine 61 and the second coating machine 64, when a coating amount of 7 g / m ² or more on one side is necessary, the jet fountain system that enables high-speed liquid supply as an applicator is used to scrape off. It is desirable to use a blade. If a coating amount of less than 7 g / m ^{2 on} one side is required, a short dwell blade coater modified for high speed may be used.

  In this case, it is desirable to provide cooling means such as water shower cooling in order to prevent burning of the blade at a high production speed when a new blade is touched after replacing the blade.

  Finally, an on-machine calendar 70 is installed, and calendar processing is performed. The illustrated calendar 70 is a 7-nip one-stack type, and has a Janus type inclined arrangement in which the influence of the roll weight is reduced. Of course, an optical load type vertical arrangement may be used.

  The calendar 70 determines the final smoothness and gloss. Therefore, various considerations are necessary from this viewpoint and from the viewpoint of high speed.

  The number of stages of the calendar 70 is not limited as long as it has at least two nips, but it is desirable to perform the flattening process with a thermal calendar composed of a combination of metal rolls M and elastic rolls D formed in a plurality of stages. In particular, a multi-nip calender, more preferably a 6-, 8-, or 10-stage multi-nip calender is optimal. FIG. 4 shows an example of a 10-stage multi-nip calendar. Furthermore, a multi-nip calender that can adjust the nip pressure independently at all stages is optimal.

  On the other hand, the heat calendar may be heated by circulating a heat medium such as oil, but this is limited to a surface temperature of about 180 ° C. In order to make paper at high speed, as shown in FIG. 7, the metal roll M is equipped with an internal heating device by electromagnetic induction that can control the division temperature in the width direction, and the surface temperature of the metal roll M is What is processed at 230 degreeC or more, especially 230-500 degreeC is desirable. In the specific example, the induction coil 71 is wound around the iron core 72 in the shell 74 to heat the heat medium passing through the jacket chamber 73.

  The surface of the metal roll M is 250 ° C. to 380 ° C., particularly more than 300 ° C. and 380 ° C. or less, so that the paper does not collapse over the entire layer at the lowest possible nip pressure. Therefore, it is possible to perform an operation that can prevent a decrease in bulk and suppress a decrease in opacity. In short, it is a form in which an extremely hot iron is applied in a short time.

  As described above, in order to control the surface temperature of the metal roll, in addition to the method of circulating hot water or oil inside the metal roll, an induction coil is provided around the iron core provided inside as the non-rotating part, and its induction By passing an alternating current through the coil, magnetic flux is generated in the coil, an induced current is induced inside the outer shell (outer cylinder) as a rotating part, and the outer shell (outer cylinder) itself is self-heated by the resistance heat. The “internal heating device using electromagnetic induction” that causes (induction heat generation) is particularly excellent for the high-temperature treatment of the present invention. Further, according to the internal heating device using this electromagnetic induction action, the induction coil is divided (for example, divided into 3 to 6) in the width direction of the roll (longitudinal direction of the roll itself), and based on the temperature signal from the temperature sensor provided in the shell. By controlling the amount of alternating current flowing through the corresponding induction coil, there is an advantage that temperature control of the surface in the width direction of the roll can be performed with high accuracy.

  In this case, in particular, a structure in which a large number of 10 to 90 jacket paths extending in the longitudinal direction are provided inside the shell at intervals in the circumferential direction, these are connected to each other, and a heat medium is sealed inside. However, it is superior in that it absorbs heat generated by self-heating of the shell and can make the heat uniform over the entire roll surface.

  According to the present invention, when the surface treatment is performed at a high temperature, not only the surface layer portion of the paper but also the temperature of the inner layer portion is increased. To do. However, when the paper is passed for a short time with a much higher high-temperature treatment, heat transfer to the inner layer portion can be prevented as much as possible, thereby preventing a decrease in bulk.

  On the other hand, as the surface temperature of the metal roll increases, stress in the thickness direction is generated in the shell of the metal roll, and the roll profile tends to collapse, thereby reducing the controllability of the paper thickness profile. In addition, when depending on the internal heating device by electromagnetic induction action, the temperature responsiveness per hour of the metal roll surface temperature cannot be said to be good, and furthermore the temperature responsiveness in the width direction is poor due to this, the temperature This causes a decrease in yield due to poor controllability. Therefore, it is desirable that near the metal roll M, at least one of an external heating device using an electromagnetic induction function capable of controlling the division temperature in the roll width direction and a cooling facility capable of controlling the cooling temperature in the roll width direction are provided.

  Explaining this example with reference to FIG. 8, the metal roll M includes a shell 74, an induction coil 71, an iron core 72, a temperature sensor 75, an AC power source 76, and a jacket path 73. For this metal roll M, an external heating device 77 by an external electromagnetic induction action that can be divided and controlled in the width direction is provided in the vicinity of the metal roll M to form a high temperature nip region of the base paper in each stage.

  The external heating device 77 applies the principle to electromagnetic induction heating. As shown in the drawing, an AC current (for example, a high frequency of 3 to 20 kHz) from an AC power source (inverter) 77B is passed through the work coil 77A to generate a magnetic field. Thus, an eddy current is generated on the surface portion of the shell 74 to cause self-heating. The distance between the work coil 77A and the surface of the shell 74 is desirably 2 to 20 mm, particularly about 2 to 5 mm. Moreover, it is desirable for the unit work coil to be disposed obliquely so as to intersect the axis of the metal roll M in order to make the heating profile uniform. The zone control pitch in the roll width direction is about 75 to 150 mm, and the rated power per zone can be 4 to 20 kW.

  As an example of the cooling equipment 78 capable of controlling the cooling temperature in the roll width direction, as shown in FIG. 9, the air from the fan 78a is sent to the header 78b, and the inside of the temperature control chamber 78d is passed through the adjustment plate 78c in which the communication holes are formed. The coil 78e provided in the temperature adjusting chamber 78d is cooled by the temperature adjusting means 78f to control the temperature of the air passing through the dispersion plate 78g having small holes.

  The nip pressure in the calendar 70 is preferably 200 KN / m to 450 KN / m, particularly 300 KN / m to 450 KN / m. The paper smoothed by the calendar 70 is finally taken up by the reel 80, and a winder (not shown) for finishing the take-up for subdivision is installed in the final part of the machine.

  Instead of the multi-nip calender shown in FIG. 4, as shown in FIG. 5, for example, a soft calender 70 </ b> A made up of metal rolls M and elastic rolls D made up of four stacks in one nip may be used.

The effect of the present invention will be clarified by examples.
The quality of the paper was evaluated by changing the factors of the wire part type, head box arrangement angle, suction form, heat calendar, heating temperature and heating form, cooling means, and papermaking speed of the present invention. In addition, Example 2 is the example previously shown along drawing. Also, it should be noted that each example is not a new line for each factor but a test example by a test plant.

The paper quality evaluation is as follows.
1. Formation evaluation: The formation evaluation specified in the examples is evaluated by using a sheet formation tester manufactured by Toyo Seiki Co., Ltd., and taking the variation in transmitted light amount as a time-series signal. In this measuring machine, 28 points can be measured in the range of unevenness wavelength of about 0.16 to 80 mm, but in the example, 14 points in the range of 4.0 to 80 mm are subjected to watermark registration in the sensory test. Since there is a close relationship with the formation that appears as a large shading, the sum of the fluctuation rates in this range was measured. When the unevenness index is less than 6%, the formation is very uniform, the uneven glossiness of the coated paper due to the formation unevenness hardly occurs, the formation of the coating layer becomes uniform, and printing at the time of printing Unevenness, uneven printing gloss, etc. are eliminated, and printability is improved.
2. Specific volume: Measured according to JIS P 8118.
3. Gloss: Measured according to JIS P 8142 at an angle of 75 degrees.
4). Gloss unevenness: A4 size test paper was prepared, and five grades were visually evaluated by five women and five men. An evaluation of 3 or higher was regarded as an acceptable level.
5. Unevenness of printing: Forty-six plate size test papers were prepared, printed on a Roland offset press, left in a constant room for 24 hours, and then the sample black, magenta, cyan, yellow four-color overprint solid printing section Evaluation was made on a five-point scale by five women and five men. An evaluation of 3 or higher was regarded as an acceptable level.
6). Yellow change: A4 size test paper was prepared, and five grades were visually evaluated by five women and five men. An evaluation of 3 or higher was regarded as an acceptable level.
7). Productivity: Five operators evaluate the test machine by observing the stability of the wet end in each example, dewaterability at the press part, drainage, and the occurrence of streaks with five operators. did. An evaluation of 3 or higher was regarded as an acceptable level.
8). Comprehensive evaluation: All quality items were comprehensively evaluated in four stages.

The base paper conditions are as follows.
<Creation of paper base>
A base paper having a basis weight (absolutely dry) of 60 g / m ² was prepared by blending the following pulp and internal chemicals to prepare a paper substrate.
<Pulp formulation>
LBKP (watering degree 350 mlcsf): 30 parts by weight NBKP (watering degree 420 mlcsf): 70 parts by weight The paper base was prepared with the above-described pulp blending and the following internal chemical compounding.
<Combination of internal chemicals>
-Light calcium carbonate: 10 parts by weight (average particle size: 3.4 μ, calcite system)
・ Commercial alkyl ketene dimer internal sizing agent (AKD): 0.03 part by weight ・ Commercial cationized starch: 0.2 part by weight ・ Commercial cationic polyacrylamide yield improver: 0.03 part by weight <Coating paper Create>
A coating solution having the following composition was smeared on the above-mentioned paper substrate with a blade coater at 9 g / cm ² on one side and dried.
<Contains topcoat coating solution>
It is as follows.
(Pigment)
Spindle type light calcium carbonate (TP121, 3.4 μm manufactured by Okutama Kogyo): 30 parts by weight Commercially available kaolin (Amazon 88, average particle size: 0.8 μm): 70 parts by weight (binder and additive)
・ Commercially available phosphoric acid esterified starch (MS4400 manufactured by Nippon Shokuhin Kako): 1 part by weight ・ Styrene butadiene latex (manufactured by Nippon Synthetic Rubber 0617): 12 parts by weight : 0.3 part by weight · Sodium hydroxide: 0.15 part by weight

"Discussion"
It can be seen that, according to the present invention, compared to the comparative example, the high-quality paper can be obtained while being high-speed papermaking.

It is an outline explanatory view showing the 1st zone of the example of equipment composition of a paper machine. It is a schematic explanatory drawing which shows the 2nd zone of the equipment structural example of a paper machine. It is an outline explanatory view showing the 3rd zone of the example of equipment composition of a paper machine. It is a schematic explanatory drawing which shows the 4th zone of the equipment structural example of a paper machine. It is a schematic explanatory drawing which shows the modification in the 4th zone of the equipment structural example of a paper machine. It is outline | summary explanatory drawing which shows the ejection of the paper stock of a head box. It is a schematic explanatory drawing which shows a heating metal roll. It is a schematic explanatory drawing which shows the example of an internal heating apparatus by an electromagnetic induction effect | action. It is an outline explanatory view showing an example of cooling equipment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st wire, 2 ... 2nd wire, 3 ... Head box, 5 ... Blade, 10 ... Twin wire former, 21 ... 1st press, 22 ... 2nd press 22, 40 ... Size press, 41 ... Air turn bar, DESCRIPTION OF SYMBOLS 50 ... Pre-calender, 51 ... Metal roll, 52 ... Elastic roll, 61 ... 1st coating machine, 64 ... 2nd coating machine 64, 70 ... On-machine calendar, M ... Metal roll, D ... Elastic roll, 80 ... reel.

Claims (7)

A method for producing coated paper, wherein the following continuous steps are incorporated in order in an on-machine.
A paper making process using a gap type twin wire former that forms a paper layer by ejecting paper from the head box between two looped wires.
Forming a wet paper with a dewatering means using a suction (forming) roll and / or a blade in the wire part;
Drying wet paper,
Nip process with pre-calender,
Applying an aqueous coating liquid mainly composed of an adhesive and a pigment;
A step of flattening with a thermal calendar composed of a combination of metal rolls and elastic rolls configured in a plurality of stages having at least two nips.   The method for producing a coated paper according to claim 1, wherein the papermaking speed is 1300 m / min or more.   The pre-calender is a combination of a metal roll and an elastic roll, the surface roughness (JIS B 0601) of the metal roll is 2.5 to 4.5 μm, and the Shore D hardness of the elastic roll is 90 or more. Item 3. A method for producing a coated paper according to Item 1 or 2.   The manufacturing method of the coated paper of any one of Claims 1-3 whose nip pressure in a pre-calender is 5 KN / m-50 KN / m.   The method for producing a coated paper according to any one of claims 1 to 4, wherein the step of applying the aqueous coating liquid is performed by blade coating.   The manufacturing method of the coated paper of any one of Claims 1-5 which makes the surface temperature of the metal roll of a heat calendar the heating temperature of 130 degreeC or more. A coated paper manufacturing facility in which the following continuous means are incorporated in order in an on-machine.
Means for paper making with a gap type twin wire former that forms a paper layer by ejecting paper from the head box between two looped wires,
Means for forming wet paper with a dewatering means by suction (forming) rolls and / or blades in the wire part;
Means for drying wet paper,
A pre-calendar that nips and flattens the base paper
Means for applying an aqueous coating liquid mainly composed of an adhesive and a pigment;
Means for flattening with a thermal calender composed of a combination of metal rolls and elastic rolls configured in multiple stages having at least two nips.

Images