JPH07133035A - Ink jet recording device and method - Google Patents

Abstract

PURPOSE:To provide an ink jet recording device which can carry out recording with high quality in a stable manner, by suppressing the influence of a cock ring, etc. CONSTITUTION:An ink jet recording device is equipped with an electrostatic sucking means 14 which alternately has a plurality of the first region which is formed on the reverse surface side for the ink recording surface of a recording medium 6, in an ink recording region and where the recording medium 6 in the ink recording region is electrostatically sucked relatively strong, and the second region where the recording medium 6 is electrostatically sucked relatively weak, in dispersion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus and a recording method provided with a mechanism for adsorbing a recording medium by electrostatic adsorption means, and in particular, the present invention is for carrying out recording while eliminating the influence of cockling and the like as much as possible. Recording device. Here, the recording means a print, and the print includes ink application to all ink supports that receive various ink applications such as cloth, thread, paper, plastic sheet, and flexible sheet material. The present invention can be applied to any of various information processing apparatuses or a printer as an output device thereof.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, the distance between the surface of the recording medium and the recording head must be kept constant in order to perform stable recording. Therefore, a means for adsorbing the recording medium to the transport system is required. An example of this means is US Pat. No. 5,245,3.
No. 64 discloses that a charge is injected from a high-voltage power supply to a surface insulating layer of a two-layer belt for conveyance having an insulating layer and a conductive layer through a charger, a roller, etc., thereby uniformly covering the entire surface of a recording medium. And means for adsorbing and transporting in cooperation with each other.

However, in the above-mentioned patent specification, in the conveyance belt adsorption, electric charges are discharged into the air by the time the conveyance belt moves from the position where the adsorption force is applied to the conveyance belt by the charging roller to the position where ink is ejected. Therefore, there is also provided an invention in which a strong adsorption is uniformly performed so as to find a defect that the adsorption force is reduced and to supplement the amount of decrease in the adsorption force by this discharge in advance.

Generally, the recording ink uses water as a main solvent, and when the recorded image has a high density, a large amount of water is driven into the recording medium, and the recording medium swells and has a size. It is known that the recording medium has a corrugated corrugated sheet shape, that is, cockling occurs in the printing section due to the large size, but there is no fundamental solution to this phenomenon.

The inventors of the present invention have a new problem that local concentration of cockling occurs as the cockling is fundamentally prevented from occurring unlike the prior art, and the recording medium is entirely removed. It has been found that there is a problem in that the cockling of some recording media abnormally grows and rubs the ink jet recording head even though the recording medium is conveyed uniformly.

Therefore, as a result of studying this problem, there is a limit to pressing the recording medium completely and carrying out close contact uniformly as in the conventional technical idea, and the present invention is rather a reverse idea. This is done by allowing the occurrence of cockling and then controlling the height of the cockling so as not to affect printing. More specifically, in the conventional uniform and strong close contact conveyance, since the suction force is uniformly generated in the width direction of the recording medium,
The swelling of the recording medium cannot be absorbed or escaped. Finally, cockling of a degree that the recording medium floats up to 2 mm or more occurs at one to several unspecified positions of the recording medium, and the recording medium comes into contact with the recording head. There is also a drawback that the image is disturbed and the discharge nozzle of the recording head is clogged.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above technical problems and to provide an ink jet recording apparatus capable of performing stable recording while suppressing disadvantages such as cockling as much as possible.

Another object of the present invention is to reliably hold the recording medium at the recording position until the final step of sheet feeding regardless of the presence or absence of swelling by the ink, and to perform recording with a small margin on the recording medium. Another object of the present invention is to provide an ink jet recording method capable of guaranteeing high quality recording.

[0009]

In order to achieve the above object, the invention according to claim 1 provides an ink jet recording apparatus having an ink recording area for a recording medium at a position separated from an ink jet recording head. A first area, which is provided on the back surface side of the recording medium in the recording area with respect to the ink recording surface, and which relatively electrostatically adsorbs the recording medium in the ink recording area, and a second area, which electrostatically adsorbs relatively weakly. It is characterized by comprising electrostatic attraction means having a plurality of regions alternately dispersed.

Here, the invention according to claim 2 is the invention according to claim 1.
In the inkjet recording apparatus described above, the first region may be a region provided with a comb-teeth electrode pair, and the second region may be a region corresponding between the comb-teeth electrode pairs.

According to a third aspect of the present invention, in the ink jet recording apparatus according to the second aspect, a dielectric may be filled between the electrode pairs.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the electrostatic attraction means is
A conveyance belt that moves at a position separated from the inkjet head may be provided on each of the first region and the second region.

Here, the invention according to claim 5 is the invention according to claim 4.
In the inkjet recording apparatus described in the above, the electrodes of the electrostatic adsorption means may be arranged such that both end edges of the electrostatic attraction means along the transport direction of the recording medium pass therethrough.

According to a sixth aspect of the present invention, in the ink jet recording apparatus according to the fourth aspect, the ink jet recording head constitutes a recording head cartridge together with an ink tank for storing ink supplied to the ink jet recording head, and the recording is performed. The head cartridge may be attachable to and detachable from a carriage that is movable in a direction orthogonal to the direction in which the recording medium is conveyed by the conveying belt.

According to a seventh aspect of the invention, in the ink jet recording apparatus according to the second aspect, when the number of the electrodes is X and the length of the recording medium to be attracted in the electrode arrangement direction is L. To obtain the minimum distance α between the recording medium and the recording head with respect to the height Z of deformation of the recording medium due to ink recording (Z <Y: when the distance between the recording medium and the recording head is Y). Things

[0016]

[Equation 3]

(However, L may be an absolute value when the length is expressed in mm unit).

According to an eighth aspect of the present invention, in the ink jet recording apparatus according to the second aspect, when one of the electrode pairs is grounded and no attraction force is generated, the number of the electrodes is X.
When the length of the recording medium to be attracted in the electrode arrangement direction is L, the height of deformation of the recording medium due to ink recording is Z (Z <Y: the distance between the recording medium and the recording head is Y). For obtaining the minimum distance α between the recording medium and the recording head,

[0019]

[Equation 4]

(However, L may be an absolute value when the length is expressed in mm unit).

According to a ninth aspect of the present invention, in the ink jet recording apparatus according to the fourth aspect, the recording medium is conveyed to at least an upstream side of the ink recording area in a recording medium conveying path formed by the conveying belt. A recording medium pressing means for pressing the belt may be further provided.

In the ink jet recording apparatus according to the ninth aspect of the present invention, the pressing means may be provided near the downstream side of the recording section.

According to a tenth aspect of the present invention, in the ink jet recording apparatus according to the ninth or tenth aspect, at least a portion of the recording medium pressing means that is in contact with the recording medium is formed of a conductive material. Good.

According to a twelfth aspect of the present invention, there is provided an ink jet recording method, wherein an ink recording area for a recording medium is provided at a position separated from an ink jet recording head, and the back surface side is opposite to the ink recording surface of the recording medium. And a plurality of second areas that are electrostatically attracted to the recording medium in the ink recording area and that are relatively weakly electrostatically attracted to each other are alternately dispersed. It is characterized in that ink recording is performed by dispersing the cockling concentration of the recording medium due to recording.

According to a thirteenth aspect of the present invention, there is provided a liquid ink recording method, which has a plurality of adsorption regions for partially electrostatically adsorbing the recording medium in an ink recording region for applying the liquid ink to the recording medium. Is characterized in that the cockling concentration of the recording medium is dispersed.

[0026]

According to the present invention, the attraction force is generated on the electrode plate,
Almost no adsorption force is generated between the electrodes. Since the direction of this electrode extends in the same direction as the recording medium conveyance direction,
A strong and weak distribution of the attraction force is formed in the width direction of the recording medium. Therefore, the swelling of the recording medium, which particularly occurs when the recorded image has a high density, can be absorbed between the plurality of electrodes that hardly generate the adsorption force. That is, since the swelling of the recording medium is absorbed by the plurality of cocklings at a specific position, each cockling can be kept low. as a result,
It is possible to prevent contact between the recording medium and the recording head.

Further, since the attracting force generating means in the present invention is based on electrostatic force, no noise is generated.

Further, according to the present invention, the recording medium is sucked and held on the back side of the recording area of the recording medium by the suction action generated along the transporting means, and the recording medium is moved by the transporting means to perform recording. Since it can be performed, it is possible to perform the recording while the ink discharge ports of the recording head and the recording surface of the recording medium are sufficiently close to each other, and the margins at both ends in the conveying direction of the recording medium can be made extremely small. . In addition, the length of the recording medium in the installation direction of the electrode is L (mm)
When the number of electrodes is X and the height Z of deformation of the recording medium due to ink recording is Z (Z <Y: when the distance between the recording medium and the recording head is Y), the recording medium and the recording medium are recorded. To obtain the minimum distance α between the heads,

[0029]

[Equation 5]

By maintaining the relationship of (where L is the absolute value when the length is expressed in mm), it is possible to prevent the recording medium from swelling due to ink ejection and cockling. Can be kept to a minimum.

Further, according to the present invention, in addition to the suction force generating means for suctioning the recording medium to the transportation belt, the transportation belt has a transportation belt for transporting the recording medium. Since the recording medium pressing means for pressing the recording medium on the conveying belt side is provided on the conveying path, the recording medium can be adsorbed and held on the conveying belt and recording can be performed while moving the conveying belt. It is possible to perform recording in close proximity while maintaining a predetermined distance between the ejection nozzles of the head and the recording medium, and it is possible to make the margin portion on the recording medium very small.

Further, the attraction force generating means and the recording medium pressing means attract the recording medium to the side of the conveyor belt, thereby minimizing cockling caused by the swelling of the recording medium due to the ink ejection. it can.

Further, the recording medium pressing means is used as a ground because the recording medium pressing means is constituted by a conductive member, and the mechanical medium pressing means is constituted by a conductive member in order to adsorb the recording medium to the conveyor belt. Or a charge having the same polarity as the charge applied to the attraction force generating means, which is generated on the recording surface of the recording medium by applying a charge having a polarity opposite to that of the charge applied to the attraction force generating means to the recording medium pressing means. (Surface potential) can be discharged via the recording medium pressing means. As a result, the electric charges (surface potential) generated on the recording surface
Can be prevented from affecting the recording, and stable recording can be performed.

Even when the edge of the recording medium is wavy or curled due to changes in the environment such as temperature and humidity, the recording medium pressing means presses the recording medium toward the conveyor belt. Since the recording medium can be conveyed to the suction force generating means, stable suction can be performed in the recording area.

[0035]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a partially cutaway perspective view showing an ink jet recording apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is an ink jet recording head (hereinafter referred to as recording head) that ejects ink to perform recording, 2 is a carriage that supports the recording head 1 and moves, and 3 is a guide that supports the carriage 2. Guide rails 4 and 4 are motors for driving the carriage 2 (not shown)
A pulley directly connected to the recording medium, a wire 5 wound around the pulley 4 and a driven pulley (not shown), a recording medium (also referred to as a recording sheet) 6 such as paper, and a recording head 1 when the recording head 1 is on standby or the like. 1 is a cap member for protecting the discharge nozzle from drying and the like, and 8 is an endless belt shape made of synthetic resin such as polyethylene, polycarbonate, polyester having a thickness of about 0.15 mm that moves while adsorbing the recording medium 6. Conveyor belt that is not used, 9 is drive roller 1
A motor that drives the conveyor belt 8 via 0 and a driven roller 11 that follows the drive roller 10.

Reference numeral 12 is an arrow showing the moving direction of the carriage 2, and 13 is an arrow showing the rotating direction of the drive roller 10.

Reference numeral 14 is a suction force generating means, which is arranged at a position facing the recording head 1 with the conveyor belt 8 interposed therebetween. Reference numeral 15 denotes a pair of comb-teeth electrodes, which generate an attracting force when a predetermined voltage is applied, and are connected to a high voltage power source (not shown) that generates a predetermined high voltage. These electrodes 15 and the power supply form a suction force generating means 14 in a schematic manner.

Reference numeral 16 is a protective film that protects the conveyor belt 8 from sliding on the comb-teeth electrode 15, and 17 is a platen plate that supports the comb-teeth electrode 15.

When recording is performed in the apparatus having the above-mentioned structure,
The recording head 1 is separated from the cap member 7, and the recording head 1 is scanned along with the carriage 2 in the direction of the recording medium 6 by the power transmitted from the motor (not shown) through the pulley 4 and the wire 5 wound around the driven pulley (not shown). After moving the length of, the cap member 7 is turned over. That is, the recording head 1 reciprocates in the direction of the arrow 12 to eject ink droplets to a predetermined position on the recording medium 6 for recording.

On the other hand, the recording medium 6 is attracted to the flat portion of the conveyor belt 8 by the attraction force based on the electrostatic force applied from the attraction force generating means 14, and is moved by a predetermined length each time the scanning of the recording head 1 is completed. 9 is sent in the direction of arrow 13 and recording can be performed by repeating these series of operations. At this time, the left and right end portions of the recording medium 6, that is, both end portions along the conveying direction, are easily floated from the conveyor belt 8. Therefore, the right and left end portions of several kinds of recording media which are decided to be used in advance are electrodes having a strong adsorption force. The comb-teeth-shaped electrode 15 is arranged so as to come to the top.

FIG. 2 shows a recording medium 18 of B5 size and A4.
FIG. 3 is a plan view showing an example of the arrangement of the comb-teeth electrodes 15 in the present embodiment when one side of each recording medium is used as a reference for conveyance, taking the recording medium 19 of a size as an example. FIG. 6A and 6B are plan views showing an arrangement example of the comb-teeth electrodes 15 in the present embodiment when the center of each recording medium is used as a reference for transporting the recording medium 19 of A4 size as an example. Figure 2
Alternatively, by disposing the comb-teeth electrodes 15 in the arrangement relationship as shown in FIG. 3, the floating of the left and right end portions of the recording medium 6 from the transport belt 8 can be reliably prevented, and the recording head 1 due to the floating.
It is possible to prevent contact with.

In the above recording operation, when the recorded image has a high density, the recording medium 6 shown in FIG. 1 is in a state in which a large amount of recording ink using water as a main solvent is ejected, and the recording medium is No. 6 swells and becomes large in size. Here, the recording medium 6 is attracted to the conveyor belt 8, but the recording medium 6
However, since the comb-teeth electrode 15 is arranged to extend along the transport direction of the recording medium 6 by the transport belt 8, the swelling of the recording medium 6 is prevented. A strong and weak distribution of the adsorption force is formed at. Therefore, the swelling of the recording medium 6 can be absorbed between the plurality of electrodes that hardly generate an attractive force. That is, since the plurality of cock rings absorb at a specific position, each cock ring can be kept low, and contact between the recording medium 6 and the recording head 1 can be prevented.

Further, since the comb-teeth electrode 15 extends along the direction in which the recording medium 6 moves, the portion that has been attracted until now is attracted when the recording head 1 enters the next scan after the transport belt 8 moves. The cockling can be suppressed low through one recording medium without moving between the electrodes. Further, since the comb-teeth electrode 15 is arranged near the lower side of the recording head 1, cockling at least in the recordable area by the recording head 1 can be suppressed.

(Embodiment 2) FIG. 4A is a schematic plan view showing a comb-shaped electrode which constitutes a part of the attraction force generating means in the second embodiment of the ink jet recording apparatus of the present invention.

In this embodiment, the edge portions of the comb-teeth-shaped electrode 15 are all rounded. By doing this, the electrode 15
It is possible to reduce the leakage from the electrode, thereby reducing the distance between the electrodes, and increasing the number of comb teeth of the comb-teeth electrode.

Other configurations and operations are the same as those of the previous embodiment.

Incidentally, FIG. 4B is a schematic plan view showing a modification of the comb-teeth-shaped electrode shown in FIG. In the embodiment shown in FIG. 4A, the pair of comb-teeth-shaped electrodes 15 are arranged so as to face each other. However, as shown in FIG. The electrode 15 may be used, and the other may be a rod-shaped electrode 15 '. In this case, an electrostatic attraction force is generated between the tips of the teeth of the comb-shaped electrode 15 and the rod-shaped electrode 15 '. In the modification shown in FIG. 4B, the generated electrostatic attraction force is smaller than that in the embodiment shown in FIG. 4A, but the modification shown in FIG. 4B can sufficiently achieve the purpose. .

(Embodiment 3) FIG. 5 is a schematic plan view showing a comb-teeth-shaped electrode which constitutes a part of the attraction force generating means in the third embodiment of the ink jet recording apparatus of the present invention. In the present embodiment, in addition to the pair of comb-teeth-shaped electrodes 15 of the attraction force generator shown in FIG. 1, another pair of comb-teeth-shaped electrodes 15 ″ is provided in parallel in the moving direction of the recording head 1. is there.

For example, when a frequently used recording medium of A4 size or smaller is used, only a pair of comb-teeth electrodes 15 are used, and only when a recording medium having a larger size than that is used, a pair of combs is used. In addition to the tooth electrode 15, a pair of comb-shaped electrodes 15 ″ is used, so that the used electrode is selectively used according to the size of the recording medium to reduce power consumption.

Other configurations and operations are the same as those in the first embodiment.

In this embodiment, the transport reference position is located at one end of the pair of comb-teeth-shaped electrodes 15. However, the center of the entire electrodes can be used as the transport reference. That is,
In this embodiment, another pair of comb-teeth electrodes 15 ″ is provided on the other end of the pair of comb-teeth electrodes 15;
By providing a pair of comb-teeth-shaped electrodes 15 ″ at both ends of the above, it is possible to use the center of the electrode as the reference of conveyance.

(Fourth Embodiment) FIG. 6 is a schematic perspective view showing a fourth embodiment of the ink jet recording apparatus of the present invention.
The same components as those in the embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 6, 4a is a drive pulley directly connected to the drive motor 9, and 4b is a driven pulley. Wire 5
Is stretched between the driving pulley 4a and the driven pulley 4b and moves the carriage 2. Reference numeral 20 is a sheet feeding motor for feeding the recording sheet 6, 22 is a cap member for protecting the ejection nozzles of the recording head 1 from drying, etc. while the recording head 1 is on standby, and 25 is for feeding the recording sheet 6. A feeding roller 26 for pressing the recording sheet 6 toward the feeding roller 25 by a biasing means (not shown), and a cap member 22.
It is an empty ejection box located closer to the recording area and allowing the recording head 1 to perform ink droplet ejection other than recording, so-called idle ejection (or preliminary ejection).

The carriage 2 moves in the directions of arrows P and P'at a predetermined timing, and ink is ejected from the recording head 1 at the timing of the movement scanning to perform recording.

When recording, the cap member 2
Recording head 1 whose ejection nozzle is protected by 2
Is released from the cap member 22, power from the motor 9 is transmitted to the carriage 2 by the wire 5, and ink droplets are ejected toward the recording sheet 6 by the recording head 1 that moves and scans with the carriage 2 for recording. . The recording sheet 6 is fed in the direction of arrow F by the sheet feeding motor 20 and the feeding roller 25 by a predetermined length each time the scanning of the recording head 1 is completed, and the recording is continuously performed on the entire surface of the sheet by repeating these operations. It becomes possible to do.

Reference numeral 28 denotes a sheet holding member which moves while adsorbing and holding the recording sheet 6 and is about 0.1 mm to 0.2 mm.
It is formed of a synthetic resin such as polyethylene or polycarbonate having a thickness of about 100 mm, and is stretched between rollers 25 and 30 in the form of an endless belt. Reference numeral 31 denotes a suction force generating means, which is fixed at a position facing the recording head 1 and generates a suction force at a portion of the sheet holding member 28 corresponding to recording by the recording head 1 when a predetermined voltage is applied. And is connected to a high-voltage power supply (not shown) that generates a predetermined high voltage. The roller 25 is driven by the sheet feeding motor 20.

In the ink jet recording apparatus having such a structure, at the time of recording, the recording sheet 6 is pressed by the pressing roller 26 via the sheet holding member 28 and the roller 2.
As shown in FIG. 1, the recording sheet 6 is directly attracted by the sheet holding member 28 to which the attraction force is generated by the attraction force generating means 31 while being pressed toward the ink ejection surface 5 of the recording head 1. Held in.

Therefore, the recording sheet 6 kept in this state
In contrast, the carriage 2 of the recording head 1 scans the ink in the direction of the arrow P to eject ink from the ink ejection port toward the recording sheet 6, and the roller 25, The sheet feeding in the direction of arrow F by 20 and the sheet holding member 28 is repeated.

At this time, since the sheet holding member 28 for holding the recording sheet 6 can feed the sheet while adsorbing the portion of the recording sheet 6 facing the recording head 1, the leading end portion and the rear portion of the recording sheet 6 can be fed. Since there is no part to travel to the recording head 1 side even when recording the end portion,
It is possible to perform recording while the ink ejection ports of the recording head 1 and the adsorbed end of the recording sheet 6 are close to each other, and it is possible to minimize the margin portion on the recording sheet 6.

Next, the structure of the attraction force generating means 31 will be described in detail with reference to FIGS. 7 and 8.

As shown in FIG. 7, a protective film 32 is provided along the lower surface of the sheet holding member 28 corresponding to the recording area, and is in contact with the sheet holding member 28.

Like the sheet holding member 28, the protective film 32 is also made of a synthetic resin material such as polyethylene or polycarbonate having a thickness of about 0.1 to 0.2 mm. Here, the protective film 32 is the electrode base 33.
Is fixed to the bottom surface of the protective film 32 by an adhesive or the like.
And 35 are provided and keep contact with the protective film 32. In addition, these electrode plates 34 and 35 are used for the electrode base 3
It is fixed to 3 by adhesion or the like.

Further, as shown in FIG. 8, the electrode plates 34 and 35 are both formed in a comb-teeth shape, and are arranged in such a manner that the respective convex portions enter the respective concave portions at a predetermined interval. There is. Then, a positive or negative voltage is applied to one of the electrode plates 34, and a voltage of the opposite polarity to the electrode plate 34 is applied to the other electrode plate 35, or the voltage is grounded.

Incidentally, R represents the distance between the comb teeth of both the electrode plates 34 and 35, and L represents the length (sheet width in the case of FIG. 8) (mm) of the recording sheet 6 in the arrangement direction of the electrodes. Show.

Next, with reference to FIG. 9, the cockling (sheet rippling phenomenon) on the recording sheet 6 which is attracted onto the electrode plates 34 and 35 through the protective film 32 and the sheet holding member 28 will be described.

Here, when a large amount of ink is ejected toward the recording sheet 6, the recording sheet 6 swells and tries to spread in a direction in which its size increases. However, in the present embodiment, the recording sheet 6 is adsorbed to the sheet holding member 28 by the adsorption force generated on the electrode plates 34 and 35, so that the bulging portion of the recording sheet 6 that swells and expands has an adsorption force. Concentrated in the interval R between the non-existing electrodes and rising to the head 1 side, a wavy cockling as shown in FIG. 9 is generated.

It should be noted that Z in FIG. 9 indicates the amount of swelling (cockling amount) of the recording sheet 6, and Q is the length along the bulge of the recording sheet 6 with respect to the interval R between the electrodes.

Assuming that the swelling ratio when ink is ejected onto the recording sheet 6 is a, the length L (m of the recording sheet 6 is
The elongation amount of m) in the same direction is indicated by La. In addition, the amount of absorption of the elongation of the recording sheet 6 in one mountain of the cockling is represented by QR, so the amount of the cockling is Z.
The number Mx of cocklings to keep

[0070]

[Equation 6]

It is shown by.

It has been confirmed by experiments that the maximum elongation of the recording sheet during high-density recording is about 1% in terms of swelling rate. On the other hand, in order to reduce the gap between the ink ejection surface of the recording head 1 and the recording sheet 6 and improve the ejection accuracy of ejection, the cockling amount Z is 0.2 mm.
It is desirable to hold down to a certain degree. Also, the distance R between the electrodes
Requires a space of at least 2 mm or more (when the voltage applied to the electrodes is 0.5 kV to 3 kV) in order to prevent discharge during that period. Therefore, in the case where the swelling rate is 1% and the cockling amount at that time is held to 0.2 mm and the distance between the electrodes is 2 mm, the condition when the number Mx of cockling peaks is most necessary Becomes

Further, the interval R between the electrodes is set to 2 mm,
The length Q along the bulge of the recording sheet 6 when the cockling amount is suppressed to 0.2 mm is about 2.0.
It has been proved by experiments that the length becomes 4 mm.

Then, by substituting these numerical values into the above equation,

[0075]

[Equation 7]

That is, the above expression shows the condition when the number Mx of cockling peaks is required to be large.

Next, the number Mx of the cockling peaks is the smallest when the recording sheet 6 is a sheet which hardly swells even when the ink is hit, like the OHP sheet. There is no problem even if the number Mx of cockling peaks is 0.

If the cockling amount Z is within a range that does not hinder recording, it is not necessary to increase the number X of electrodes more than necessary, and the electrode width l (see FIG. 8) is set. It is desirable to make the adsorption range as wide as possible. For example, in the case of the above-mentioned OHP sheet, it is only necessary to adsorb the sheet, and in this case, the number of positive and negative electrodes may be one, and the sheet can be adsorbed by the entire electrode.

Therefore, from the above analysis result, in order to determine the number Mx of crests of the cockling, the number X of electrodes and the length L are determined.
Between

[0080]

[Equation 8]

It suffices if the conditions shown in are satisfied. Here, L is an absolute value when the dimension in the electrode arrangement direction in the area where the sheet is attracted is expressed in mm.

Further, of the two electrode plates, the electrode plate on the side dropped to the ground may have a weaker attracting force, and the peak of the cockling may occur on the electrode plate dropped to the ground. In some cases, the number of electrodes X needs to be twice the number Mx of cockling peaks. Therefore, to determine the number of electrodes,

[0083]

[Equation 9]

It suffices if the conditions shown in are satisfied.

The height Z of deformation of the recording medium due to ink recording (Z <Y: when the distance between the recording medium and the recording head is Y), the minimum distance α between the recording medium and the recording head, and the electrode. When the number X and the length L in the electrode arrangement direction of the recording medium are set,

[0086]

[Equation 10]

The relational expression of was obtained as a more preferable condition.

Incidentally,

[0089]

[Outer 1]

It shows the existence ratio of the strong electrostatic adsorption region which can be more uniformly dispersed. It has been found that satisfying this lower limit value is preferable because the image quality and texture of the image can be improved. Further, in the present invention,
Although there is no numerical limitation on the upper limit value (however, the present invention does not include the entire surface strong adsorption area), but in terms of transportability and cost when the recording medium is repeatedly stopped and fed repeatedly.

[0091]

[Outside 2]

That is, for ink jet recording,
The upper limit value and the lower limit value in the above equation 10 are valid.

This is because the deformation height Z of the recording medium is Z = Y.
Since it is −α, the number of electrodes X needs to be large when the deformation height Z of the recording medium must be kept small, and the number of electrodes may be small when Z may be large. It becomes a relationship. In addition, when one of the electrode pairs is grounded and no attracting force is generated, the number of electrodes that is twice the number of electrodes when the attracting force is generated on both of the electrode pairs is required. Because,

[0094]

[Equation 11]

The following relationship is required.

(Embodiment 5) FIG. 10 is a schematic sectional view showing a fifth embodiment of the ink jet recording apparatus of the present invention. The above-described fourth embodiment is an example of application to an inkjet recording apparatus of the type in which the recording sheet 6 is conveyed along the sheet holding member 28 formed of an endless belt. In contrast to the fourth embodiment, in the fifth embodiment, roller pairs 26 and 25, 36 and 30 are arranged on the upstream side and the downstream side of the recording head 1 in the sheet feeding direction, respectively. An example of application to a system in which the recording sheet 6 is held and conveyed between a pair of rollers will be described.

In this embodiment, the upstream roller pair 26, 25
A suction force generating means 31 for suctioning the recording sheet 6 is arranged along the conveyance path between the roller pair 36 and 30 on the downstream side.

Here, the basic structure and operation of the attraction force generating means 31 are the same as those in the fourth embodiment, so that the description of those parts will be omitted.

(Embodiment 6) FIG. 11 is a schematic plan view showing a sixth embodiment of the ink jet recording apparatus of the present invention. In the fourth and fifth embodiments described above, the arrangement direction of the teeth of the comb-teeth-shaped electrode plates 34 and 35 provided in the attraction force generating means 31 is set to the direction perpendicular to the transport direction. In the example, the teeth are arranged in the same direction as the carrying direction, that is, in the case of the serial type having the form shown in FIG. 6, the teeth are arranged in the scanning direction of the recording head 1. In this case, the extension of the recording sheet 6 may be restricted with respect to the length LS (mm) in the sheet feeding direction. Therefore, in this embodiment, the number of comb teeth (the number of electrodes) X and the interval R between the tooth dies may be set according to the above-described embodiment. Specifically, the number X of electrodes is

[0100]

[Equation 12]

It is preferable to satisfy the relationship of (where α is the minimum distance between the recording medium and the recording head), and when one of the electrode pairs is grounded and no suction force is generated,

[0102]

[Equation 13]

It is preferable to satisfy the relationship of [0103], and the applied voltage is preferably in the range of 2 to 3 kV.

Note that other configurations are shown in FIGS.
Since it is the same as the embodiment shown in FIG.

(Embodiment 7) FIG. 12 is a schematic perspective view showing a seventh embodiment of the ink jet recording apparatus of the present invention. The same components as those in the fourth embodiment shown in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.

The feature of this embodiment is that a paper pressing member 40, which will be described later, is provided in the structure of the fourth embodiment, and that a dielectric 41 is embedded between the electrode plates in the attraction force generating means 31. It is in. The electrostatic attraction force at the location of the dielectric 41 is relatively weaker than the electrostatic attraction force on other electrodes.

The paper pressing member 40 is attached as a recording medium pressing means for pressing the recording medium 6 to the conveying belt side, with the rotation shaft of the pressing roller 26 as the center of rotation, and is attached to the conveying belt 28 side by a biasing means (not shown). Being energized. The paper pressing member 40 is formed of a conductive metal plate.

In the recording apparatus having such a structure, in addition to the function and effect of the fourth embodiment, the recording medium 6 held between the pressing roller 26 and the conveying belt 28 and guided to the recording portion is held by the paper pressing member 26. While being pressed against the conveyor belt 28 side, it enters the suction force generating portion, and the suction force given from the suction force generating means 31 efficiently sucks the flat portion of the conveyor belt 28.

When a large amount of ink is ejected onto the recording medium 6 and when cockling occurs on the recording medium 6, the suction force of the suction force generating means 31 and the paper pressing member 40.
Since the recording medium 6 is attracted to the conveying belt 28 side by the pressing force of, the "floating" of the recording medium 6 to the recording head 1 side is eliminated. Therefore, stable recording can be performed without accidental contact between the recording head 1 and the recording medium 6.

Further, even when the end portion of the recording medium 6 is wavy or curled due to changes in environment such as temperature and humidity, the recording medium 6 is pressed against the conveyor belt 28 by the paper pressing member 40. Since the sheet can be conveyed to the suction force generating section in a state where the wrinkles and curls have been removed, stable suction can be performed in the recording section.

Next, the suction force generating means 31 is shown in FIG.
And it demonstrates using FIG.

FIG. 13 is a sectional view seen from the direction of arrow A in FIG. 12, and FIG. 14 is a plan view seen from the direction of arrow B in FIG. In FIG. 13, similarly to the fourth embodiment shown in FIG. 7, a protective film 32 is provided below the conveyor belt 28 and is in contact with the conveyor belt 28. The protective film 32 is also 0.1 to 0.2 m like the conveyor belt 28.
It is made of synthetic resin such as polyethylene and polycarbonate having a thickness of about m. The protective film 32 is fixed on the electrode base 33 by adhesion or the like.

Below the protective film 32, there are an electrode plate 34 and a ground plate 35 made of a conductive metal, which are in contact with the protective film 32. The electrode plate 34 and the ground plate 35 are fixed to the electrode base 33 by adhesion or the like. As shown in FIG. 14, the electrode plate 34 and the ground plate 35 have a comb-teeth shape, and are arranged in such a manner that the respective convex portions are inserted into the respective concave portions. A positive or negative voltage is applied to the electrode plate 34, and the ground plate 35 is grounded. In the space between the electrode plates 34 and the ground plates 35,
A dielectric 41 is embedded in order to increase the suction efficiency of the recording medium 6 by the suction force generating means 31.

When a voltage is applied to the electrode plate 34, a suction force is generated on the conveyor belt 28 through the protective film 32,
On the recording surface of the recording medium 6, electric charges (surface potential) having the same polarity as the voltage applied to the electrode plate 34 are generated. At this time,
The conductive paper pressing member 40 is grounded, or is applied with a voltage having a polarity opposite to that of the voltage applied to the electrode plate 34, that is, a voltage having a polarity opposite to the charge generated on the recording surface of the recording medium 6. , It is possible to eliminate charges on the recording surface (surface potential), prevent the recording from being affected, and perform stable recording.

(Embodiment 8) FIG. 15 is a sectional view showing an eighth embodiment of the ink jet recording apparatus of the present invention.

In the seventh embodiment, the recording medium pressing means 40 is made of a conductive metal plate, but in this embodiment, as shown in FIG. 15, a conductive metal or resin is used. A paper pressing member using the brush-shaped charge removing member 42 in which the above fibers are bundled may be used. With such a configuration, it is possible to reliably prevent the recording medium 6 from being lifted by the brush-shaped charge removing member 42, and to efficiently remove static electricity on the surface of the recording medium 6.

Since the other structure is the same as that of the embodiment, its explanation is omitted.

(Embodiment 9) FIG. 16 is a sectional view showing a ninth embodiment of the ink jet recording apparatus of the present invention.

In the seventh embodiment, the paper pressing member 40 is arranged on the upstream side of the recording area, but in this embodiment, the paper pressing member 43 is arranged as shown in FIG.
May be arranged on the downstream side of the recording area. Further, the paper pressing member may be arranged only on the downstream side.

(Embodiment 10) FIG. 17 is a sectional view showing a tenth embodiment of an ink jet recording apparatus of the present invention, and FIG. 18 is a view for explaining a control method of the recording apparatus shown in FIG. It is a flowchart.

With reference to FIGS. 17 and 18, the control of the suction force generation means will be described in relation to the feeding / recording operation of the recording medium in each of the above embodiments.

In FIG. 17, reference numeral 44 is the suction force generating means 3
1 is a control means for controlling the ON / OFF operation. The control means 44 is connected to a paper edge sensor 45 arranged at a position on the upstream side of the recording area, and when the leading edge of the recording medium 6 reaches the paper edge sensor 45, the suction force generating means 3 is provided.
1 control can be performed.

The control procedure will be described with reference to FIG.

First, the paper feeding operation for feeding the recording medium to a predetermined position in the recording area is started. By this operation, the paper edge sensor 4
When the recording medium 6 reaches 5 (S1), electrostatic attraction is started on the recording medium (S2), and then the recording medium 6
When the is set to the recording start position, recording is started (S
3).

Next, when recording on the recording medium 6 is completed by the recording head 1 for only a few lines (S4), the procedure returns to step S3, and when recording for one sheet is completed (S4). After releasing the suction by the suction force generating means 31 (S5), the recording medium 6 is conveyed and discharged (S5).
6).

Next, if there is another recording medium 6 to be recorded (S7), the process returns to the step before the previous step S1, and if there is no recording medium 6 to be recorded, the recording is ended as it is. .

By performing such control, the leading end of the recording medium can be set quickly and surely, and the effect of mitigating cockling dispersion can be obtained during recording.

Further, since the suction force is released at the time of discharging, the suction load at the time of discharging can be reduced.

In each of the above-described embodiments, the roller pair is provided on the upstream side and the downstream side of the recording area, and the endless conveyor belt is stretched around these roller pairs to convey the recording medium. A platen roller may be used to convey the medium, and the rotational force of the platen roller may efficiently convey the recording medium.

(Others) The present invention is provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ejecting ink, particularly in the ink jet recording system. The present invention brings about excellent effects in a recording head and a recording apparatus of the type in which the state of ink is changed by the heat energy. This is because such a system can achieve high density recording and high definition recording.

Regarding its typical structure and principle, see, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal in a one-to-one correspondence
It is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Furthermore, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the electrical connection to the main body of the apparatus or the ink from the main body of the apparatus by being mounted on the main body The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, etc. because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, or a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to control the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, by applying thermal energy such as ink that is liquefied by applying thermal energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, other than the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmitting / receiving function are provided. It may be a form or the like.

[0139]

As described above, according to the present invention,
In an ink jet recording apparatus that ejects ink by an attraction force generating means for recording, when a large amount of ink is ejected, the phenomenon that the recording medium undulates due to the ink penetrating into the recording medium is suppressed to a minimum, and the recording medium and the recording head There is an effect of preventing contact with the recording head and an effect of preventing contact with the recording head due to floating of the end portion of the recording medium due to rigidity of the recording medium itself.

Further, according to the present invention, the recording medium adsorbing means by the electrodes arranged along the conveying means is provided on the back surface side of the recording area of the recording medium, and the number of the electrodes is adsorbed by X. When the length of the recording medium in the electrode installation direction is L, the height Z of the recording medium formed by ink recording (Z <Y:
(When the distance between the recording heads is Y), the recording medium is to obtain the minimum distance α between the recording heads.

[0141]

[Equation 14]

However, since L is an absolute value when the length is expressed in mm, it is possible to prevent the recording medium from swelling due to ink ejection and cockling. It is possible to obtain high-quality recording with the ink ejection port close to the recording medium, and it is possible to remarkably reduce the margins at both ends of the recording medium in the sheet feeding direction. Can be secured.

Furthermore, according to the present invention, since the recording medium can be adsorbed and held on the conveyor belt and recording can be performed by moving the conveyor belt, the discharge nozzle at the end of the recording head and the end of the recording medium are separated from each other. Recording can be performed in close proximity to each other, and the margin portion on the recording medium can be made extremely small.

Further, the so-called cockling, which is generated by the swelling of the recording medium due to the impact of the ink by adsorbing the recording medium to the conveying belt side by the suction force generating means and the recording medium pressing means, can be minimized. be able to. Further, since the attracting force generating means using the electrostatic attracting force is provided in the structure for attracting the recording medium to the conveyor belt and the recording medium pressing means is constituted by the conductive member, it is easy to use the electrostatic force for attracting. Therefore, it is possible to prevent the electric charges (surface potential) generated on the recording surface from affecting the recording, and it is possible to perform stable recording.

In addition, due to changes in environment (temperature, humidity),
Stable recording is possible even when the edge of the recording medium is wavy or curled.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment of an inkjet recording apparatus of the present invention.

FIG. 2 is a schematic plan view showing a recording medium arranged on one side as a reference on a comb-shaped electrode which constitutes a part of the attraction force generating means in the embodiment shown in FIG.

FIG. 3 is a schematic plan view showing a recording medium arranged with reference to the center on a comb-teeth-shaped electrode forming a part of the attraction force generating means in the embodiment shown in FIG.

FIG. 4 (a) is a schematic plan view showing a comb-teeth-shaped electrode forming a part of the attraction force generating means in the second embodiment of the inkjet recording apparatus of the present invention, and FIG. 7 is a schematic plan view showing a modified example of the comb-teeth-shaped electrode shown in FIG.

FIG. 5 is a schematic plan view showing a comb-teeth-shaped electrode which constitutes a part of the attraction force generating means in the third embodiment of the ink jet recording apparatus of the present invention.

FIG. 6 is a schematic perspective view showing a fourth embodiment of the inkjet recording apparatus of the present invention.

7 is a schematic sectional view of the recording apparatus shown in FIG.

8 is a schematic plan view of the recording apparatus shown in FIG.

9 is a schematic cross-sectional view for explaining a phenomenon of cockling that may occur in a recording medium in the recording apparatus shown in FIG.

FIG. 10 is a schematic sectional view showing a fifth embodiment of the inkjet recording apparatus of the present invention.

FIG. 11 is a schematic plan view showing a sixth embodiment of the inkjet recording apparatus of the present invention.

FIG. 12 is a schematic perspective view showing a seventh embodiment of the ink jet recording apparatus of the present invention.

13 is a schematic cross-sectional view as seen from the direction of arrow A in FIG.

FIG. 14 is a schematic plan view seen from the direction of arrow B in FIG.

FIG. 15 is a schematic cross-sectional view showing an eighth embodiment of the inkjet recording apparatus of the present invention.

FIG. 16 is a schematic sectional view showing a ninth embodiment of the ink jet recording apparatus of the present invention.

FIG. 17 is a schematic sectional view showing a tenth embodiment of the inkjet recording apparatus of the present invention.

FIG. 18 is a flowchart for explaining a control method of the recording apparatus shown in FIG.

[Explanation of Codes] 1 Inkjet recording head 2 Carriage 3 Guide rail 4 Pulley 5 Wire 6 Recording medium 7 Cap member 8 Conveyor belt 9 Drive motor 10 Drive roller 11 Driven roller 12 Arrow indicating the moving direction of the moving base 13 Rotation of the drive roller Directional arrow 14 Adsorption force generating means 15 Comb-shaped electrode 16 Protective film 17 Platen plate 18 B5 size recording medium 19 A4 size recording medium 20 Sheet feeding motor 21 Adsorption force generating means 22 Cap member 23 Electrode plate 24 Earth plate 25 Roller Pair 26 Roller Pair 28 Sheet Holding Member 30 Roller Pair 31 Adsorption Force Generating Means 32 Protective Film 33 Electrode Base 34 Electrode Plate 35 Electrode Plate 36 Roller Pair 40 Paper Pressing Member (Upstream Side) 41 Dielectric 42 Charge Eliminating Member 43 Paper Pressing Member (downstream side) 44 control Means 45 the paper end sensor

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 27, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0093

[Correction method] Change

[Details of correction] This is because the deformation height Z of the recording medium is Z = Y-α. Therefore, if the deformation height Z of the recording medium must be kept small, a large number of electrodes X is required. Therefore, when Z may be large, the number of electrodes may be small. In addition, when one of the electrode pairs is grounded and no attracting force is generated, the number of electrodes is twice as large as when the attracting force is generated on both electrode pairs.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0102

[Correction method] Change

[Correction content]

[Equation 13]

Claims (13)

[Claims] 1. An ink jet recording apparatus having an ink recording area for a recording medium at a position separated from an ink jet recording head, wherein the ink recording area is provided on the back surface side with respect to the ink recording surface of the recording medium. And an electrostatic attraction unit having a plurality of first areas that relatively electrostatically attract the recording medium and second areas that relatively weakly electrostatically attract the recording medium in the ink recording area. Inkjet recording device. 2. The ink jet recording apparatus according to claim 1, wherein the first region is a region provided with comb-teeth electrode pairs, and the second region is a region corresponding to between the comb-teeth electrode pairs. An ink jet recording apparatus characterized by being present. 3. The ink jet recording apparatus according to claim 2, wherein a dielectric is filled between the pair of electrodes. 4. The ink jet recording apparatus according to claim 1, wherein the electrostatic adsorption unit is provided on each of the first area and the second area with a conveyor belt moving at a position separated from the ink jet head. An ink jet recording apparatus characterized by having in. 5. The ink jet recording apparatus according to claim 4, wherein the electrodes of the electrostatic attraction means are arranged such that both end edges of the recording medium in the transport direction pass over the electrodes. An ink jet recording apparatus characterized by the above. 6. The ink jet recording apparatus according to claim 4, wherein the ink jet recording head constitutes a recording head cartridge together with an ink tank that stores ink supplied to the ink jet recording head, and the recording head cartridge comprises the transport belt. An inkjet recording apparatus, wherein the inkjet recording apparatus is detachable on a carriage movable in a direction orthogonal to a recording medium conveyance direction. 7. The ink jet recording apparatus according to claim 2, wherein the number of the electrodes is X, and the length of the recording medium to be adsorbed in the electrode arrangement direction is L.
To obtain the minimum distance α between the recording medium and the recording head with respect to the height Z of deformation of the recording medium due to ink recording (Z <Y: when the distance between the recording medium and the recording head is Y). Then, (However, L is the absolute value when the length is expressed in a unit of mm). 8. The ink jet recording apparatus according to claim 2, wherein when one of the electrode pairs is grounded and no adsorption force is generated, the number of the electrodes is X and the electrodes of the recording medium to be adsorbed. When the length in the arrangement direction is L, the height Z of deformation of the recording medium due to ink recording (Z <Z <
Y: When the distance between the recording medium and the recording head is Y), the minimum distance α between the recording medium and the recording head is obtained. (However, L is the absolute value when the length is expressed in a unit of mm). 9. The ink jet recording apparatus according to claim 4, wherein recording is performed by pressing the recording medium toward the conveyor belt at least near an upstream side of the ink recording area in a recording medium conveyance path formed by the conveyor belt. An ink jet recording apparatus further comprising a medium pressing unit. 10. The ink jet recording apparatus according to claim 9, wherein the pressing unit is also provided in the vicinity of the downstream side of the recording unit. 11. The ink jet recording apparatus according to claim 9 or 10, wherein the recording medium pressing means is made of a conductive material at least in a portion in contact with the recording medium. . 12. An ink recording area for a recording medium, which is provided at a position separated from an ink jet recording head, is provided on a back surface side with respect to an ink recording surface of the recording medium, and the recording medium in the ink recording area is relatively disposed. By the electrostatic attraction means having a plurality of first areas that are strongly electrostatically attracted and second areas that are relatively weakly electrostatically attracted are alternately dispersed to disperse the cockling concentration of the recording medium by ink recording. An ink jet recording method characterized by recording. 13. The cockling concentration of the recording medium is dispersed by having a plurality of adsorption areas for partially electrostatically adsorbing the recording medium in an ink recording area for applying the liquid ink to the recording medium. Liquid ink recording method.