Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
1999-01-06
2001-08-07
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C347S030000, C400S656000
Reexamination Certificate
active
06270215
ABSTRACT:
FIELD OF TECHNOLOGY TO WHICH THIS INVENTION BELONGS
The present invention relates to raster-type printers (plotters) such as inkjet type and the like which are used as output equipment for CAD computers, and more particularly, relates to printers provided with a paper float preventing mechanism that keeps a recording medium from floating on a paper support surface in a printing unit.
BACKGROUND OF THE INVENTION
In the inkjet printers of this kind, when ink is discharged onto the recording medium, an influence of wave-like deformation such as crumpled paper (hereinafter called cockling) must be eliminated as much as possible, and an interval between a recording medium and a recording head must be maintained constant. Furthermore, a paper floating from above a platen toward a direction of the head must be prevented. In order to solve the problems mentioned in the foregoing, an inkjet recording device is disclosed in Japanese patent laid open publication H9-48161 wherein a plurality of concave portions and a plurality of convex portions are provided on an upper portion of the platen, and furthermore, a paper holding plate is disposed to be in contact with the plurality of concave portions, and projections are provided on the paper holding plate at positions corresponding to the plurality of concave portions. Furthermore, in Japanese patent laid open publication H7-256955, a printer mechanism provided with ribs on an upper surface of the platen as a countermeasure of cockling is disclosed.
Furthermore, generally, as a paper feeding mechanism for inkjet plotter (printer), for example, as being disclosed in Japanese patent laid open publication H9-11566, [mechanism wherein a recording paper is retained under pressure by means of a main roller and a holding roller of drum type, and is sandwiched by means of a subroller and a spur type roller, and thus, the floating of the paper is prevented and is carried toward a discharge outlet along an upper position guide plate while it being in tight contact] is employed.
Moreover, in inkjet plotter (printer) of pinch roller type has been developed wherein the paper is caused to make a tight contact on a flat drafting member formed with a plurality of ventilation holes by means of a suction force of a suction device, and both sides of the paper are sandwiched by means of a drive roller and a pinch roller, and the paper is fed in a predetermined X-axis by the rotation of the drive roller while the inkjet type recording head is caused to reciprocate in a Y-axis direction to perform a recording on the paper by means of the recording head. Furthermore, a mechanism is known wherein an unevenness (jogs) guide unit consisting of a plurality of convex stripes and adjacent concave grooves is provided on a base plate of the drafting member, and the recording is carried out on the paper which is disposed on the unevenness guide unit, and the paper is under pressure at a lower stream of a recording position by means of the spur type roller thereby preventing the paper floating.
In order to prevent the paper floating by providing convex portions or ribs on the platen or by positioning a portion of the paper that is curved downward at the concave portions formed between the convex portions or the ribs, there is a necessity of forcing the lower surface of the paper to contact the convex portions or the ribs. The conventional device has a construction wherein the projections of the paper holding plate are caused to contact the paper before it comes to the printing unit or the paper is caused to make a curve by the paper guide before it comes to the printing unit, and the paper is caused to contact the ribs by means of the pressure. However, the projections of the paper holding plate cannot be disposed in the vicinity of a printing area so that the paper cannot be caused to contact the convex portions. Also, a method of causing the paper to contact the ribs by taking advantage of the curve of the paper cannot obtain a sufficient pressurizing force.
Furthermore, in case of using the drafting member having a flat perforated paper support surface, the paper that absorbs the ink at the time of recording inflates. The suction device causes problems such as the inflated portion is not adsorbed onto the paper support surface by vacuum force, or the paper floating occurs that causes the recording head rubs on the paper. In addition, when the paper is caused to be in direct contact with the spur type roller, an adverse influence occurs on the quality of picture and the spur type roller stains the paper after recording.
An object of the present invention is to solve the foregoing points.
SUMMARY OF THE INVENTION
In the present invention, the recording medium is sandwiched by the drive roller and the pinch roller, and the recording medium is carried onto the drafting member by the rotation of the drive roller. The recording head reciprocates in a direction perpendicular to a carrying direction of the recording medium on a print range of the drafting member to carry out the recording on the recording medium. A predetermined range of the drafting member and its movements before and after the recording is such that the suction force is produced by the suction device and the recording medium is attracted to the support surface of the drafting member. An unevenness (jogs) guide unit having suction holes is formed on the drafting member, and the cockling (wave-form rumples) of the recording medium is absorbed by the unevenness guide unit which prevents the paper floating. This unevenness guide unit comprises a plurality of convex portions that are arranged in a row which extends in the X-axis direction in parallel with the carrying direction of the recording medium and the adjacent concave portions, and suction holes open to the upper surface of the concave portion or the convex portion of the drafting member, or the suction holes open to the upper surface of both the concave portion and the convex portion.
Still, furthermore, in the present invention, a cut plateau that is lower than the paper support surface of the unevenness guide unit of the drafting member is formed on the lower stream side having a predetermined interval from a drafting position of the drafting member, and the second unevenness guide unit is provided in adjacency of the lower steam side of the cut plateau, and the height of the paper support surface of the second unevenness guide unit is arranged to be lower than the height of the paper support surface of the unevenness guide unit of the drafting member.
As described in the foregoing, the present invention generates the suction force at the drafting position and the paper support surface of the unevenness guide unit formed at its lower stream, which prevents the paper floating and eliminates the rubbing of the paper with the recording head. Moreover, the recording of high picture quality can be carried out as the inflated portion of the paper that absorbs the ink adsorbs onto the unevenness guide unit by means of the contactless vacuum force.
Furthermore, the present invention generates the vacuum force on the upper surface of the convex stripes by perforating the suction holes for adsorption on the convex stripes so that the floating of the recording medium can be prevented efficiently. Moreover, the inflated portion of the recording medium that absorbs the ink is adsorbed onto the unevenness guide unit by means of the contactless vacuum force whereby an interval between the recording head and the recording medium is set constant, which carries out the recording of high picture quality.
REFERENCES:
patent: 5874979 (1999-02-01), Ohyama
patent: 6038776 (2000-03-01), Yamada et al.
patent: JP 59155075 A (1984-09-01), None
patent: JP 60090785 A (1985-05-01), None
patent: JP 11301880 A (1999-11-01), None
Miyasaka Toshiaki
Namiki Takeshi
Nozawa Shinya
Ohtani Tsuyoshi
Barlow John
Mutch Industries Ltd.
Shah M.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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