JP2004136559A - Ink-jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet printer which can form high-quality images by suppressing an instantaneous travel speed change of an endless belt for transferring a recording medium, and by suppressing generation of printing irregularities because of the travel speed change. <P>SOLUTION: The endless belt for transferring the recording medium is formed in a loop by joining its both ends. A joined part where the both ends are joined is slant in a width direction of the endless belt. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet printer, and more particularly to an ink jet printer suitable for application to ink jet textile printing.
[0002]
[Prior art]
In the ink jet recording system, dots are formed by ejecting minute ink droplets from a recording head and attaching the droplets to a recording medium such as paper, thereby recording images and characters. It is used in various fields such as various printers, facsimile machines, and computer terminals because it has low noise, does not require processes such as development and fixing, and can be easily printed in full color. ing.
[0003]
When performing printing on a fabric, when the ink is ejected from the recording head to form an image while holding and transporting the fabric by a driving roller and a driven roller, the fabric is compared with paper or a film sheet. Since there is no so-called waist (rigidity), wrinkles are liable to occur when the sheet is conveyed by such a driving roller and a driven roller, and thus a formed image may be distorted or deformed. In order to avoid this, there is a method in which an endless belt is hung on a plurality of rollers including one drive roller so that an appropriate tension is applied, the endless belt is run by the drive roller, and the fabric is conveyed by the endless belt. .
[0004]
Further, there is an endless belt in which both ends in the running direction are joined to form a loop (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-7-180748 (paragraphs [0010] to [0014], FIG. 1)
[0006]
[Problems to be solved by the invention]
However, when an endless belt having such a joint as shown in FIG. 9A is used as such an endless belt, when the joint passes through a driving roller, as shown in FIG. In the case where the joint of the belt does not bend evenly when it is applied to the drive roller, it is bent at the joint and becomes a convex shape that apexes the joint, or when a reinforcing material is provided in the joint and its vicinity, the same figure (C) When the reinforcing material hangs on the drive roller as shown in (c), the reinforcing material instantly rides on the drive roller, or as shown in FIG. Due to a sudden decrease in the flexibility of the belt, the running speed of the endless belt is instantaneously changed, and the belt cannot be conveyed at a constant speed. As a result, the image formed on the fabric, such as deformation or uneven density, is printed. May cause unevenness Was Tsu. Similarly, when the belt is detached after being caught on the driving roller, the running speed of the endless belt is also instantaneously changed, thereby causing printing unevenness.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress an instantaneous change in the traveling speed of an endless belt that conveys a recording medium and suppress the occurrence of printing unevenness due to the change in the traveling speed. To provide an ink jet printer capable of forming a high quality image.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 provides a recording head that discharges ink onto a recording medium, and is provided to face the recording head, and is rotated by a driving roller to convey the recording medium. In an ink jet printer having an endless belt, the endless belt is formed in a loop shape by joining both ends thereof, and a joined portion where the both ends are joined is oblique in a width direction of the endless belt. And
[0009]
According to a second aspect of the present invention, there is provided an ink jet printer comprising: a recording head for discharging ink onto a recording medium; and an endless belt provided to face the recording head, rotated by a driving roller, and transporting the recording medium. In the endless belt, the endless belt is made of a non-conductive material, and the both ends thereof are joined to form a loop, and the joined portion where the both ends are joined is oblique in the width direction of the endless belt, A recording medium conveyed by the endless belt is adsorbed via the endless belt at a position facing the recording head so that the endless belt is movably abutted on the inner peripheral surface side of the endless belt. And a means for generating an electrostatic attraction force.
[0010]
The invention according to claim 3 is characterized in that the endless belt has a surface resistance value of 10 ⁸ Ω or more. Further, it is more preferably 10 ¹³ Ω or more.
[0011]
Further, the invention according to claim 4 is characterized in that the endless belt includes a reinforcing material for reinforcing the joining portion, and the reinforcing material is oblique in the width direction of the endless belt along the joining portion. Features.
[0012]
The invention according to claim 5 is characterized in that the joining portion of the endless belt is formed such that both joined ends are inclined in the thickness direction.
[0013]
According to a sixth aspect of the present invention, in the joining portion of the endless belt, both joined ends are formed with inclined surfaces in a thickness direction, and both ends are joined via a reinforcing material for reinforcing the joined portion. The reinforcing member has one end in the thickness direction provided on the outer peripheral surface of the endless belt, and the other end provided along the inner peripheral surface of the endless belt, and the width direction of the endless belt along the joining portion. It is characterized by being oblique.
[0014]
The invention according to claim 7 is such that the one end side and the other end side of the reinforcing member form an obtuse angle with respect to the slope in the thickness direction when viewed in a circumferential cross-sectional shape of the endless belt. It is characterized by being provided.
[0015]
Further, in the invention according to claim 8, the joint portion is formed by setting an angle between the joint portion and a width direction of the endless belt to θ, a length of the endless belt in a circumferential direction to L, and a width of the endless belt to L. W, where R / W <tanθ <L / W is satisfied, where R is the length of the endless belt wound around the drive roller.
[0016]
The invention according to claim 9 is characterized in that the endless belt has a thickness of 1 mm or less. Further, it is more preferably 0.3 mm or less.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an inkjet printer for textile printing provided with a transport mechanism using an endless belt according to the present invention.
[0018]
According to FIG. 1, an ink jet printer for textile printing is a method in which a cloth 1 is suspended and rotated by rollers described below for transporting the fabric 1 as a recording medium in a transport direction while the fabric 1 is in close contact (for example, a surface resistance value). An endless belt 5 made of a non-conductive material having a resistance of 10 ⁸ Ω or more (the reason for the non-conductive material will be described later) and a fabric 1 as a recording medium rotatably held by holding means (not shown) are formed. An original winding 1a, a recording head 2 positioned downstream of the original winding 1a in the transport direction of the fabric 1 and ejecting ink from a plurality of nozzles (not shown) to form an image on the fabric 1, and a carriage holding the recording head 2 3, a carriage rail 4 for guiding movement when the carriage 3 is moved along a main scanning direction (perpendicular to the plane of FIG. 1) by a moving means (not shown); A driving roller 6 rotates clockwise by an unillustrated driving means to rotate the endless belt 5, a guide roller 7 suspended around the endless belt 5 and rotatably provided, and is pressed by unillustrated urging means. The endless belt 5 is given an appropriate tension, and the fabric 1 and the endless belt 5 are sandwiched between the driving roller 6 and the tension roller 9 rotatably supported by the shaft. And a holding roller 10 rotatably provided, and an electrostatic chuck disposed so as to face the recording head 2 via the endless belt 5 and to be in contact with the inner peripheral surface of the endless belt 5. It mainly comprises an electrostatic attraction plate 11 as a force generating means.
[0019]
With such a configuration, the following operation is realized in the ink jet printer for textile printing according to the present embodiment. The fabric 1 unwound from the original winding 1a is conveyed in the direction of the arrow shown in the figure, is sandwiched by the driving roller 6 and the pressing roller 10 together with the endless belt 5, and is conveyed in close contact with the endless belt 5. Then, in accordance with the progress of the conveyance, the scanning of the carriage 3 and the ejection of the ink from the recording head 2 are appropriately controlled, so that the ink jet printing is performed on the cloth 1.
[0020]
Here, before describing the endless belt 5, the electrostatic attraction plate 11 will be described first with reference to FIG. FIG. 2A is a top view of the electrostatic suction plate 11, and FIG. 2B is a cross-sectional view taken along a cutting line AA shown in FIG. 2A. As shown in FIG. 2, a comb-shaped electrode plate 101 and a comb-shaped ground plate 102 are fixed on an insulating substrate 103 in a nested state at an interval from each other. On the upper portion of the plate 102, a surface adsorption layer 104 made of a high dielectric substance is formed. The electrostatic attraction plate 11 is arranged as shown in FIG. 1 so that the surface attraction layer 104 contacts the inner peripheral surface of the endless belt 5.
[0021]
Next, the electrostatic attraction force generated between the electrostatic attraction plate 11 and the cloth 1 will be described with reference to FIG. When a DC voltage is applied to the electrode plate 101 and the earth plate 102, a dielectric polarization phenomenon occurs in the surface adsorption layer 104 to excite electric charges having different polarities, and a negative voltage is generated above the electrode plate 101 as shown in FIG. At the top of the earth plate 102 (shown as “−”), the state becomes plus (shown as “+” in FIG. 3). Since the endless belt 5 of the present embodiment is made of a non-conductive material, a charge opposite to the charge of the surface adsorption layer 104 is generated on the cloth 1 on the endless belt 5 as shown in FIG. Therefore, an electrostatic attraction force is generated between the electrostatic attraction plate 11 and the cloth 1 by the electrostatic force.
[0022]
When a recording medium such as a cloth is conveyed in close contact with an endless belt using an electrostatic attraction force generating means such as the electrostatic attraction plate 11 as described above, an endless Preferably, the belt is made of a non-conductive material. Here, the endless belt made of a non-conductive material only needs to have such a resistance that the electric charge generated by the electrostatic attraction force generating means does not flow. In the present embodiment, the endless belt 5 is made of such a non-conductive material. Specifically, the surface resistance value is 10 ⁸ Ω or more, and in this case, the electric charge generated in the surface adsorption layer 104 does not easily flow through the endless belt 5 and the electrostatic force between the electrostatic adsorption plate 11 and the cloth 1 is reduced. Is more likely to occur, and it becomes easier to convey the fabric 1 in close contact with the endless belt 5 uniformly. Further, it is preferable that the surface resistance is 10 ¹³ Ω or more. In this case, the charge generated in the surface adsorption layer 104 is almost kept, so that a sufficient electrostatic adsorption force is obtained and Can be easily performed without any problem. In order to realize such a surface resistance value, the endless belt 5 is made of a material obtained by, for example, applying a treatment for increasing the water repellency of the surface to a glass cloth woven with fibers woven with glass fibers. In this embodiment, the treatment for increasing the water repellency of the surface is performed by applying a fluorine coating as a specific example.
[0023]
By using the non-conductive endless belt 5 as described above, the fabric 1 is brought into close contact with the endless belt 5 by the electrostatic attraction force generated between the electrostatic attraction plate 11 and the fabric 1, and the drive roller 6 is driven. When the endless belt 5 is driven and rotated in the transport direction, a frictional force is generated between the fabric 1 and the endless belt 5 because the fabric 1 is given a force in the direction of the endless belt 5 by an electrostatic attraction force. The fabric 1 moves together with the endless belt 5.
[0024]
However, in order to uniformly and closely convey the paper, the electrostatic attraction force generated between the electrostatic attraction plate 11 and the cloth 1 must be sufficient. Since the electrostatic attraction force is a force of pulling electric charges, that is, a Coulomb force, it is inversely proportional to the square of the distance. Since the distance is the thickness of the endless belt 5, even if the endless belt 5 has the above-described surface resistance value, the thickness is large. In some cases, it is not possible to obtain a sufficient electrostatic attraction force. In the present embodiment, specifically, by setting the thickness of the endless belt 5 to 1 mm or less, the electrostatic force between the electrostatic attraction plate 11 and the fabric 1 is not weakened, and the fabric 1 is connected to the endless belt 5. Can be conveyed uniformly in close contact. When the thickness is 0.3 mm or less, a sufficient electrostatic attraction force can be obtained, and there is no problem in transporting the fabric 1. Further, as long as it has strength and is thinner, a sufficient electrostatic attraction force can be obtained even if the surface resistance value is close to the above-mentioned lower limit of 10 ⁸ Ω. Therefore, the thickness of the endless belt 5 is desirably 1 mm or less, and more desirably 0.3 mm or less.
[0025]
Here, the joining of the endless belt 5 will be described. As shown in FIG. 4, the endless belt 5 is formed by joining both ends in the running direction by heat fusion to form a loop and hanging the rollers 6, 7, 9 on each of the rollers 6, 7, and 9. The joining portion 51 is joined so as to be inclined in the width direction of the endless belt 5 (the angle θ in FIG. 4). By joining obliquely in this manner, as shown in FIG. 5, the joining portion 51 is spirally hung at the belt-related portion between the contact start position and the contact end position of the cylindrical portion of the drive roller 6, so that the joining portion 51 Does not form a convex shape that apexes the joint.
[0026]
Further, the reinforcing member 52 is also provided obliquely along the joint portion 51. Therefore, even if the reinforcing member 52 is the surface of the endless belt 5 on the drive roller 6 side, the reinforcing member 52 rides only at the intersection of the end of the reinforcing member 52 and the line indicating the contact start position, and the intersection is The endless belt 5 moves from the far side in FIG. 6 of the line indicating the contact start position along the line indicating the contact start position in the riding position movement direction indicated by the arrow as the endless belt 5 travels. At this time, on the line indicating the contact start position other than the intersection of the line indicating the contact start position and the end of the reinforcing member 52, the endless belt 5 or the reinforcing member 52 is stably hooked. It is possible to travel with almost no influence of the vehicle. The same applies to the case where the reinforcing member 52 comes off at the contact end position, and the endless belt 5 can run almost without being affected by the point where the reinforcing member comes off.
[0027]
Further, even if the endless belt 5 has a decrease in flexibility at the reinforcing member 52, the reinforcing member 52 is gradually moved from the back side of the line indicating the contact starting position in FIG. , And gradually comes off because of the belt portion between the contact end position and the contact end position. Therefore, the endless belt 5 can travel with almost no influence of the change in flexibility.
[0028]
Here, in the case of carrying using an electrostatic attraction force as in the present embodiment, it is better that the reinforcing member 52 is also non-conductive similarly to the endless belt 5. As an example of the conductive material, a PFA (Perfluoro alkoxy alkaline polymer) film, which is one of fluororesin coating materials, was used.
[0029]
Further, the angle θ shown in FIG. 4, that is, the angle formed by the joining portion 51 and the width direction of the endless belt 5, the length of the endless belt 5 in the circumferential direction is L, the width of the endless belt 5 is W, When the length of the endless belt 5 wrapped around the drive roller 6, which is the distance on the cylindrical portion of the drive roller 6 to the contact end position, is R,
R / W <tanθ <L / W
Is desirably set so as to satisfy the following condition, so that the entire joint portion 51 does not temporarily exist between the contact start position and the contact end position. In addition, the upper limit of the above conditions is such that the joining portion 51 forms a spiral of one cycle on the endless belt 5, and in any width direction of the endless belt 5, the joining portion 51 and the reinforcing material 52 are substantially the same. Can be realized.
[0030]
Next, a specific example of joining will be described with reference to FIG. 7 showing the cut surface AA in FIG. According to FIG. 7, in the endless belt 5 joined obliquely in the width direction, both end surfaces are formed with slopes in the thickness direction, and when formed into a loop, the endless belt 5 is heat-sealed so that the slopes match. Are joined. By joining the endless belt 5 with a slope in the thickness direction, the joining area of the joining portion 51 is increased, and the joining strength is increased. Further, when the endless belt 5 is bent near the joining portion 51, a convex shape having the joining portion 51 as an apex is formed. It becomes difficult. Further, in the present embodiment, the slopes are joined via a reinforcing material 52a, and the reinforcing material 52a further has one end side in the cross section shown in FIG. , The other end is heat-sealed to the inner peripheral surface (the lower side of the cross section of the endless belt 5 in FIG. 7). Also, at this time, the reinforcing material 52a is bent at one end and the other end so as to form an obtuse angle with the slope in the thickness direction so as to follow an obtuse angle formed by the slope and the outer peripheral surface or the inner peripheral surface. Has been fused. In this manner, the swelling of the reinforcing member 52a in the thickness direction can be suppressed when the member is thermally fused by bending at an obtuse angle. Further, in order to increase the strength of the joining, the reinforcing material 52b is heat-sealed so as to cover the reinforcing material 52a and the joining portion 51. In FIG. 7, the reinforcing member 52b is provided on the outer peripheral surface, but may be provided on the inner peripheral surface or on both the outer peripheral surface and the inner peripheral surface. However, the reinforcing members 52 a and 52 b are oblique in the width direction of the endless belt 5 along the joint portion 51 on the outer peripheral surface and the inner peripheral surface of the endless belt 5.
[0031]
Further, the bonding mode shown in FIG. 7 is an example in which the bonding strength and the printing unevenness are considered in the ink jet printer for textile printing according to the present embodiment. 8 may be used. In other words, according to FIG. 8A, for example, both end surfaces of the endless belt 5 are joined by a slope without using the reinforcing material 52, and according to FIG. 8B, the end surface of the endless belt 5 (a slope may be used). ), And the joint portion is covered with the reinforcing member 52. Needless to say, the joining portion 51 is oblique in the width direction of the endless belt 5, and the reinforcing member 52 is oblique in the width direction of the endless belt 5 along the joining portion 51.
[0032]
According to such an endless belt 5, it is possible to prevent the occurrence of printing unevenness, while the traveling speed of the endless belt 5 is hardly affected by the joining portion 51 and the reinforcing material 52.
[0033]
In the above description, the fabric is used as the recording medium. However, when printing is performed on a recording medium such as paper or film using an endless belt, the traveling speed of the endless belt 5 is similarly controlled by the joining portion 51 or the like. It is possible to provide an ink jet printer that hardly receives the influence of the reinforcing member 52 and prevents the occurrence of printing unevenness.
[0034]
In the above-described embodiment, a so-called scanning head that forms an image by ejecting ink while moving the recording head 2 in the main scanning direction has been described. A so-called line head having a nozzle may be used.
[0035]
【The invention's effect】
As described above, according to the present invention, the instantaneous change in the running speed of the endless belt due to the joining portion or the reinforcing material is suppressed, and the occurrence of printing unevenness due to the instantaneous change in the running speed of the endless belt is suppressed. An ink jet printer capable of forming a high quality image can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of a mechanical configuration of an ink jet printer for textile printing according to an embodiment of the present invention.
FIGS. 2A and 2B show a configuration of an electrostatic suction plate according to the present invention, wherein FIG. 2A is a top view and FIG. 2B is a cross-sectional view taken along the line AA shown in FIG.
FIG. 3 is a diagram for describing an electrostatic attraction force generated between an electrostatic attraction plate and a cloth.
FIG. 4 is a perspective view of an endless belt and each roller for describing joining of the endless belt.
FIG. 5 is an explanatory diagram showing a state when a joining portion of the endless belt passes through a driving roller.
FIG. 6 is an explanatory diagram showing a state when a reinforcing material of the endless belt passes through a driving roller.
FIG. 7 is a cross-sectional view illustrating an example of bonding.
FIGS. 8A and 8B are cross-sectional views showing an example of joining.
FIG. 9 is an explanatory diagram for explaining a problem in a conventional endless belt.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fabric 1a Original winding 2 Recording head 3 Carriage 4 Carriage rail 5 Endless belt 51 Joining part 52 Reinforcement material 6 Drive roller 7, 8 Guide roller 9 Tension roller 10 Pressing roller 11 Electrostatic attraction plate

Claims (9)

A recording head that ejects ink onto a recording medium, and an ink jet printer that is provided to face the recording head and is rotated by a driving roller and includes an endless belt that conveys the recording medium.
An ink jet printer, wherein the endless belt is formed by joining both ends thereof into a loop shape, and a joined portion where the both ends are joined is oblique in a width direction of the endless belt. A recording head that ejects ink onto a recording medium, and an ink jet printer that is provided to face the recording head and is rotated by a driving roller and includes an endless belt that conveys the recording medium.
The endless belt is made of a non-conductive material, and is formed in a loop shape by joining both ends thereof, and the joining portion where the both ends are joined is oblique in the width direction of the endless belt,
At a position facing the recording head, the endless belt is disposed so as to movably contact the inner peripheral surface side of the endless belt, and the recording medium conveyed by the endless belt is interposed through the endless belt. An ink jet printer comprising an electrostatic attraction force generating means for attracting. The inkjet printer according to claim 2, wherein the endless belt has a surface resistance value of 10 ⁸ Ω or more. The endless belt includes a reinforcing material for reinforcing the joint,
The ink jet printer according to any one of claims 1 to 3, wherein the reinforcing member is oblique in the width direction of the endless belt along the joint. The ink jet printer according to any one of claims 1 to 4, wherein a joining portion of the endless belt is formed such that both ends to be joined are inclined in a thickness direction. The joining portion of the endless belt, both ends to be joined are formed with a slope in the thickness direction, and both ends are joined via a reinforcing material for reinforcing the joining portion,
The reinforcing member has one end in the thickness direction provided on the outer peripheral surface of the endless belt, and the other end provided along the inner peripheral surface of the endless belt, and in the width direction of the endless belt along the joining portion. The inkjet printer according to any one of claims 1 to 3, wherein the inkjet printer is oblique. The one end side and the other end side of the reinforcing member are provided so as to form an obtuse angle with respect to the slope in the thickness direction when viewed in a cross-sectional shape in a circumferential direction of the endless belt. Item 7. An inkjet printer according to Item 6. The joining portion is formed by an angle θ between the joining portion and the width direction of the endless belt, a length in a circumferential direction of the endless belt L, a width of the endless belt W, and a drive roller of the endless belt. The ink jet printer according to any one of claims 1 to 7, wherein R / W <tanθ <L / W is satisfied when the winding length of R is R. The inkjet printer according to any one of claims 1 to 8, wherein the endless belt has a thickness of 1 mm or less.

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