JP2000351499A - Paper sheet feeding device in ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high-quality printing and image forming while horizontally holding a paper sheet in relation to the printing surface of a platen. SOLUTION: A drive roller 10 and a pressurizing roller 12 are arranged upstream of a paper sheet conveying passage by taking the printing surface 2a of a platen 2 as a reference, and a cylindrical attracting roller 16 is rotatably arranged downstream. Sheet attracting force is generated on the surface of the attracting roller 16 for supporting a paper sheet by vacuum force or electrostatic attracting force. In printing and image forming, the upstream side of a paper sheet 14 is pinched between the drive roller 10 and the pressurizing roller 12, the downstream side of the paper sheet 14 is adhered to the sheet supporting surface of the attracting roller 16, and the paper sheet 14 is horizontally adhered to the printing surface 2a. The drive roller 10 and the attracting roller 16 are synchronously rotated in the same direction and driven at the approximately same peripheral speed. The paper sheet 14 is fed in the specified direction by the rotation of the drive roller 10 and the attracting roller 16, a recording head 8 is reciprocated on the printing surface 2a of the platen 2 in a direction to traverse the paper sheet 14, and printing and image forming are performed on the paper sheet 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a paper feeding device in an ink jet printer.

[0002]

2. Description of the Related Art In this type of printer, it is important that the ink discharge surface of the print recording head and the paper on the print surface thereunder are always parallel. Conventionally, the paper is pressed against the platen by a star roller to prevent the paper from floating on the printing surface, and to keep the paper parallel to the ink ejection surface of the recording head.

[0003]

The method for preventing the paper from floating on the printing surface with the star roller has a problem that the printing quality of the paper is damaged by the star roller and the printing quality is degraded. Was. An object of the present invention is to solve the above problems.

[0004]

According to the present invention, a sheet is spread on a platen, the sheet is sandwiched between a driving roller and a pressing roller, and the sheet is fixed by rotating the driving roller. On the printing surface of the platen, on the printing surface of the platen, an ink-jet printer in which a recording head is reciprocated in a direction traversing the paper so as to perform printing on the paper on the printing surface, with the printing surface of the platen as a reference The drive roller and the pressure roller are disposed on the upstream side of the paper transport path, the cylindrical suction roller is rotatably disposed on the downstream side or the printing surface, and the paper is disposed on at least the surface of the suction roller that supports the paper. A suction force is generated, the upstream side of the paper is sandwiched between the driving roller and the pressure roller, and the downstream side or the printing portion of the paper is brought into close contact with the paper support surface of the suction roller, and the driving is performed. And over La adsorption roller is obtained so as to drive to be substantially the same peripheral speed as each other is rotated synchronously in the same direction. In the present invention, the peripheral speed of the suction roller is slightly higher than the peripheral speed of the drive roller. Further, in the present invention, the sheet suction force on the surface of the suction roller is generated by a vacuum force. Further, in the present invention, the paper suction force on the surface of the suction roller is generated by an electrostatic suction force.

[0005]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Reference numeral 2 denotes a platen (paper support) for supporting and guiding the paper, and is supported by a machine body (not shown) via a gantry. Reference numeral 4 denotes a Y rail supported by the body, and a Y cursor 6 is movably attached to the Y rail via rollers.

An ink jet recording head 8 is attached to the Y cursor 6, and the ink ejection surface of the recording head 8 is horizontally opposed to the printing surface (2a) of the platen 8. A drive roller 10 is rotatably supported in a gap formed in the platen 2. The drive roller 10 is connected to an X-axis drive controlled by a controller.

Reference numeral 12 denotes a pressure roller, and the Y rail 4
In addition, it is supported so as to be able to move up and down with respect to the drive roller 10, and is in horizontal elastic contact with the drive roller 10 by a spring. The drive roller 10 and the pressure roller 12 are configured to sandwich three points on both sides and the center of the sheet 14 on the platen 2.

Reference numeral 16 denotes a suction roller formed of a cylindrical member disposed in a gap formed on the downstream side of the platen 2 with respect to the printing surface 2a and orthogonal to the direction in which the sheet 14 is conveyed. The neighboring outer peripheral surfaces are each a pair of rollers 1
It is rotatably supported by the body via 8, 20. A large number of suction holes 22 are formed in the tube wall of the suction roller 16 over substantially the entire peripheral surface.

The overall length of the suction roller 16 in the axial direction is longer than the width of the paper 14, and the upper peripheral surface of the suction roller 16 is set to be substantially the same height as the paper support surface of the adjacent platen 2. ing.

As shown in FIG. 3, a shaft 24 projects vertically from the center of one side wall of the suction roller 16, and the shaft 24 has a power transmission mechanism comprising a belt pulley 26 and a belt 28. Via an X-axis drive.

The suction roller 16 is configured to rotate synchronously with the drive roller 10 in the same direction as the drive roller 10 at the time of printing an image under the control of a controller. Further, the speed of the peripheral surface of the suction roller 16 is controlled by the drive roller 10.
Is set to be equal to or slightly higher than the peripheral speed of the driving roller.

Reference numeral 30 denotes a suction duct, which is a long bottom 3.
0a and both side walls 30b, 30b perpendicular to the bottom
And the front and rear walls 30c, 30c, and the whole is formed in an elongated box shape having an open upper part.

The opening edge of the suction duct 30 is made of a rubber material,
A vacuum chamber 34 is provided in close contact with the inner peripheral surface of the suction roller 16 via a sealing member 32 made of a brush or the like, and a predetermined range inside the paper support portion above the suction roller 16 and the vicinity thereof. The vacuum chamber 34
Is connected via a tube 36 to a suction port of a vacuum pump 38 fixed to the body. The suction duct 3
Numeral 0 is fixed to the body via a bracket 40.

Next, the operation of this embodiment will be described.
When the paper 14 is set on the platen 2, the pressure roller 12 is separated upward from the drive roller 10 by a lever operation by an operator. In this state, the paper 14 such as roll paper guided on the platen 2 is passed between the driving roller 10 and the pressure roller 12, and then the pressure roller up lever is returned to the original position to release the pressure roller 12. Lower the drive roller 1 from above the paper 14.
Make contact with 0.

When the ink jet printer shifts to the printing operation, the vacuum pump 38 is driven, and the driving roller 10 and the suction roller 16 are rotated in a counterclockwise direction in FIG.

The paper 14 on the platen 2 is sandwiched between the drive roller 10 and the pressure roller 12 on the extension plane of the print portion 2a of the platen 2 with respect to the print portion 2a of the platen 2 as a reference. The side is attracted to the upper surface of the attraction roller 16 by a vacuum force, and the paper 14 is horizontally adhered to the printing portion 2 a on the platen 2.

The paper 14 is intermittently fed by the driving roller 10 and the suction roller 16 in the left direction in FIG. 1, while the recording head 8 reciprocates along the Y rail 4 in the vertical direction in FIG. Then, printing is performed on the paper 14 on the printing surface 2a by ink droplets ejected from the recording head 8. During the rotation of the suction roller 16, the inner peripheral surface of the suction roller 16
Slides with respect to the sealing member 32.

The means for generating the sheet suction force on the surface of the suction roller is not particularly limited to a configuration using a vacuum force, but a suction roller is formed by stretching an electrostatic suction plate on the roller. A paper attraction force may be generated on the roller surface by electrostatic force. Also, the suction roller 1
Reference numeral 6 may be disposed at a position corresponding to the printing surface 2a of the platen 2, and the surface of the suction roller 16 may be used as the printing surface.

[0019]

As described above, according to the present invention, the upstream side of the paper is held between the drive roller and the pressure roller with respect to the printing surface of the platen, and the downstream side or the printing portion is sucked on the surface of the suction roller. Since the sheets are brought into close contact with each other by force, the paper can be held horizontally on the ink ejection surface of the recording head, and high quality printing can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a main part of an ink jet printer.

FIG. 2 is an enlarged side sectional view of a suction roller.

FIG. 3 is a front sectional view showing a vacuum structure of the suction roller.

[Explanation of symbols]

 2 Platen (Paper Support) 4 Y Rail 6 Y Cursor 8 Recording Head 10 Drive Roller 12 Pressure Roller 14 Paper 16 Suction Roller 18 Roller 20 Roller 22 Suction Hole 24 Shaft 26 Belt Pulley 28 Belt 30 Suction Duct 32 Sealing Member 34 Vacuum chamber 36 Tube 38 Vacuum pump 40 Bracket

Claims (4)

[Claims] 1. A sheet is spread on a platen, the sheet is sandwiched between a driving roller and a pressure roller, and the sheet is fed in a predetermined direction by rotation of the driving roller, while a recording head is formed on a printing surface of the platen. In the ink jet printer which reciprocates in the direction traversing the paper and prints on the paper on the printing surface, the drive roller and the pressure roller are arranged on the upstream side of the paper transport path with respect to the printing surface of the platen. Is disposed, a cylindrical suction roller is rotatably disposed on the downstream side or the printing surface, and a sheet suction force is generated on at least a surface of the suction roller supporting the sheet, and the upstream side of the sheet is the drive roller. And the pressure roller, the downstream side or the printing portion of the paper is brought into close contact with the paper support surface of the suction roller, and the drive roller and the suction roller are synchronously rotated in the same direction. A sheet feeder characterized in that the sheet feeders are driven so as to have substantially the same peripheral speed. 2. The paper feeder according to claim 1, wherein the peripheral speed of the suction roller is set to be slightly faster than the peripheral speed of the drive roller. 3. The sheet feeding device according to claim 1, wherein the sheet suction force on the surface of the suction roller is generated by a vacuum force. 4. The paper feeding device according to claim 1, wherein the paper suction force on the surface of the suction roller is generated by an electrostatic suction force.