JP2001334646A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high quality printing by applying a sheet tightly to the print face of a platen and keeping a constant distance between a recording head and the sheet surface. SOLUTION: A sheet carrying roller 34 and a pressing roller 38 clamps a sheet in front of a platen 18 and the sheet is fed onto the platen 18 through rotation of the sheet carrying roller 34. On the other hand, the sheet on the platen 18 is printed by reciprocating a recording head 32 transversely to the sheet on the platen 18. A tubular suction roller 12 is disposed rotatably in the rear of the platen 18 and a sheet suction force can be generated on the surface of the suction roller 12 by vacuum force. Suction holes 20 communicating with a suction unit 8 are made in the sheet supporting face of the platen 18. The sheet is clamped by the sheet carrying roller 34 and the pressing roller 38 in front of the platen 18 and carried in a specified direction through rotation of the sheet carrying roller 34 and the suction roller 12 in the same direction while being sucked to the surface of the platen 18 and the suction roller 12 with vacuum force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper holding and feeding mechanism comprising a paper transport roller and a pressure roller disposed in front of a platen. The present invention also relates to an ink jet printer in which a recording head is reciprocated in a direction crossing a recording medium on the platen while printing is performed on the recording medium on the platen.

[0002]

2. Description of the Related Art In this type of printer, it is important that the paper is always in close contact with the paper support surface of a platen disposed immediately below the movement path of the ink discharge surface of the print recording head. If the paper rises from the platen, the paper may rub the ink ejection surface of the recording head and stain the paper, or the distance between the ink ejection surface of the recording head and the paper surface may change, resulting in high-precision printing. Can not. Therefore, conventionally, the paper is pressed against the paper guide surface by a star roller behind the platen to prevent the paper from floating on the platen, and the distance between the paper and the ink ejection surface of the recording head is kept constant.

[0003]

The method of preventing the paper from floating above the platen by the above-mentioned star roller has a problem in that the printing surface of the paper is damaged by the star roller and the printing quality is degraded. . An object of the present invention is to solve the above problems. Still another object of the present invention is to make it possible to print a high-quality print while keeping the distance between the print head and the print surface constant by securely bringing the print medium into close contact with the platen.

[0004]

In order to achieve the above object, according to the present invention, there is provided a paper nipping / feeding mechanism comprising a paper transport roller and a pressure roller in front of a platen, and the rotation of the paper transport roller. In an ink jet printer which supplies a recording medium to the platen, reciprocates a recording head on the platen in a direction traversing the recording medium, and performs printing on the recording medium on the platen, a cylindrical type is provided behind the platen. The suction roller is rotatably disposed, a vacuum mechanism for generating a sheet suction force is provided on the surface of the suction roller, and an intake hole communicating with an intake device is opened in the sheet support surface of the platen, and the recording medium is moved. While the recording medium is nipped by the paper nipping and feeding mechanism and the recording medium is adsorbed on the surface of the platen and the suction roller, the paper transport roller and the suction The roller rotates in the same direction is obtained so as to convey the recording medium in a predetermined direction. Further, according to the present invention, the peripheral speed of the suction roller is set slightly faster than the peripheral speed of the paper transport roller, and tension is applied to the recording medium being transported in the forward direction.

[0005]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 2, 2
Reference numeral denotes a vacuum box, which is supported on legs (not shown) via the stands 4 and 6. As shown in FIG. 3, a plurality of the vacuum boxes 2 are arranged in the horizontal direction. Each of the vacuum boxes 2 has a built-in suction device 8, and a suction port 8 a thereof is opened inside the vacuum box 2.

On the upper wall of the vacuum box 2,
A slit 10 is formed in a direction perpendicular to the sheet transport direction, and a cylindrical suction roller 12 is disposed in the slit 10. Both ends of the suction roller 12 are rotatably supported by bearing boxes 14 arranged on both sides of the corresponding vacuum box 2. The upper part of the suction roller 12 is provided with the slit 1 so as to be exposed to the outside.
The slit 10 is disposed so as to protrude slightly above 0, and both end edges of the slit 10 are opposed to the peripheral surface of the suction roller 12 with a slight gap.

The cylindrical portion of the suction roller 12 has a ventilation hole 1.
A large number of holes 6 are provided, and the suction force generated in the vacuum box 2 is transmitted to the externally exposed surface of the suction roller 12 by driving the vacuum fan of the suction device 8. The vacuum box 2, the suction device 8, and the ventilation hole 16 constitute a vacuum mechanism that generates a sheet suction force on the surface of the suction roller 12.

The suction rollers 12 arranged in each of the plurality of vacuum boxes 2 are connected to each other via a shaft joint on the same axis, and one end of the connected suction rollers 12 is connected to a power transmission mechanism (not shown). Via an X-axis motor (not shown). A platen 18 having a paper support surface for supporting and guiding the entire width of the paper is integrally formed on the upper wall of the vacuum box 2, and an intake hole 20 communicating with the inside of the vacuum box 2 is formed in the platen 18. Many are drilled.

A single cutter groove 24 for guiding the cutter 22 is formed in the platen 18 in parallel with the slit 10 so as to reduce the friction of paper conveyance in a direction perpendicular to the cutter groove 24. Are formed. The intake hole 20 is arranged in the concave groove 26. Reference numeral 28 denotes a Y rail supported by the body of the printer, to which a carriage 30 linked to a Y-axis driving device is movably mounted via rollers.

An ink jet type recording head 32 and a cutter 22 are mounted on the carriage 30, and the ink ejection surface of the recording head 32 faces the platen 18. Numeral 34 denotes a short paper transport roller, in which a plurality of rollers 34 are coaxially arranged in parallel with the suction roller 12, and both ends of each roller 34 are supported by a printer body via a bearing box 36. Have been.

One end of the paper transport rollers 34 coaxially connected to each other is connected to an X-axis motor via a power transmission mechanism. The peripheral speed of the paper transport roller 34 when the printer is driven is set to be slightly lower than the peripheral speed of the suction roller 12 so that a tension is applied to a recording medium such as paper in the pulling direction. Reference numeral 38 denotes a pressure roller, which is supported by the Y rail 28 so as to be able to move up and down with respect to the paper transport roller 34, and is in elastic contact with the paper transport roller 34 by a spring.

In FIG. 2, reference numerals 40 and 42 denote sheet guides made of a metal plate. The sheet guides are arranged on the upstream side and the downstream side of the sheet conveying path with respect to the sheet conveying roller 34, respectively. , 6. The paper guide 42 on the upstream side has a guide surface for guiding the draw-out portion of the roll paper 44 to the paper transport roller 34, and the paper guide 40 on the downstream side moves the paper released from the suction roller 12 in a horizontal direction for a predetermined distance. And a guide surface for guiding downward.

The paper support surface of the paper transport roller 34, the paper support surface of the platen 18, the paper support surface of the suction roller 12, and the paper support surfaces of the paper guides 40 and 42 are set substantially on the same plane. 1 and 3, the paper guides 40 and 42 are not shown. Next, the operation of the present embodiment will be described.

When the sheet 44 is set on the platen 18, the pressure roller 38 is separated upward from the sheet conveying roller 34 by a lever operation by an operator. When the pressure roller 38 is in the up state, the paper 44 such as roll paper guided on the paper guide 42 is passed between the paper conveyance roller 34 and the pressure roller 38, and then the pressure roller up lever is returned to the original position. Return pressure roller 38
Is lowered to elastically contact the paper transport roller 34 from above the paper 44.

At this time, since the suction device 8 is being driven, as shown in FIG.
Adhere to Therefore, even if the leading end of the paper 44 has a curl, the leading end of the paper 44 does not rise from the platen 18 and does not rub the ink ejection surface of the recording head 32. When the inkjet printer shifts to the printing operation, the paper transport roller 34 and the suction roller 12 are driven to rotate counterclockwise in FIG.

The sheet 44 on the platen 18 is the platen 1
8, the upstream side of the paper transport path is sandwiched between the paper transport roller 34 and the pressure roller 38, and the downstream side is suctioned to the upper surface of the suction roller 12 by a vacuum force.
In the state where tension is applied to the sheet guide 4, the sheet 44 is in close contact with the upper surface of the platen 18 while the sheet guides 42 and 40
The sheet is conveyed upward in the sheet discharge direction to the left in FIG. While the paper 44 is conveyed to the left, the recording head 32
2 reciprocates in the direction perpendicular to the paper of FIG. 2 along the rails 28, and prints are formed on paper by ink droplets ejected from the recording head 32.

After the printing operation is completed, the cutter 22 is lowered on the platen 18, the cutter 22 is moved along the cutter groove 24, and the sheet 44 is cut.
Even when the sheet 44 on the fourth side is released from the suction force of the suction roller 12, the vicinity of the cut portion of the sheet 44 does not rise from the platen 18 due to the curl.

In addition, the X-axis motor is driven in reverse by operating a panel switch so that the paper 44 is back-fed as shown in FIG. At this time, due to the difference in peripheral speed between the suction roller 12 and the paper transport roller 34, the paper 4
4 is loosened, but the sheet 44 on the platen 18
Is vacuum-sucked, so that the paper 44
It does not rise from 8.

[0019]

According to the present invention, as described above, the recording medium can be brought into close contact with the printing surface of the platen, and high quality printing can be performed.

[Brief description of the drawings]

FIG. 1 is a partially sectional external view of a main part of an ink jet printer.

FIG. 2 is a side view of the inkjet printer.

FIG. 3 is an external view of an ink jet printer in which a paper guide is omitted.

FIG. 4 is a partially sectional external view of a suction roller.

FIG. 5 is an explanatory diagram of the present invention.

FIG. 6 is an explanatory diagram of the present invention.

[Description of Signs] 2 Vacuum box 4 Mount 6 Mount 8 Suction device 8a Suction port 10 Slit 12 Suction roller 14 Bearing box 16 Vent hole 18 Platen 20 Suction hole 22 Cutter 24 Cutter groove 26 Depressed groove 28 Y rail 30 Carriage 32 Recording head 34 paper transport roller 36 bearing box 38 pressure roller 40 paper guide 42 paper guide 44 roll paper 46 slack

Continued on front page F-term (reference) 2C056 HA29 HA30 2C058 AB17 AC07 AD01 AE02 AE09 AF20 AF23 AF31 AF51 AF59 AF64 DA11 DA38 DB04 DB14 GC07 GE11 LA04 LA07 LA14 LA24 LB10 LB27 LB36 3F049 AA10 CA06 DA12 FC19 LA07 LB03

Claims (2)

[Claims] 1. A sheet nipping and feeding mechanism comprising a sheet conveying roller and a pressure roller is disposed in front of a platen, and a recording medium is supplied to the platen by rotation of the sheet conveying roller, and recording is performed on the platen. In an ink jet printer in which a head is reciprocated in a direction traversing a recording medium to perform printing on a recording medium on a platen, a cylindrical suction roller is rotatably disposed behind the platen, and A vacuum mechanism for generating a sheet suction force is provided on the surface, and an intake hole communicating with an intake device is opened in the sheet support surface of the platen, and a recording medium is clamped by the sheet clamping and feeding mechanism. While adsorbing on the surface of the attraction roller, rotate the paper transport roller and the attraction roller in the same direction to move the recording medium in a predetermined direction. An ink jet printer characterized in that the ink is conveyed to the printer. 2. The recording medium according to claim 1, wherein the peripheral speed of the attraction roller is set slightly faster than the peripheral speed of the paper transport roller, and tension is applied to the recording medium being transported in the forward direction. Inkjet printer.