Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-10-19
2002-03-05
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S022000
Reexamination Certificate
active
06352334
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet printer that performs recording by discharging ink from the ink jet recording head to a recording medium. More particularly, the invention relates to an ink jet printer provided with a cleaning unit whereby to clean the discharge port surface of the ink jet recording head.
2. Related Background Art
There is a screen printing method, as a typical one, that uses silk screen form plates to print directly on paper for the production of a large poster or a camp. In accordance with this method, each of the silk screen form plates is mounted, at first, on a screen printing apparatus per color corresponding to colors used for the original image to be printed, and then, ink is transferred directly to the paper sheet through meshes of the silk screen form plates for recording.
However, it takes a great number of processes and time to prepare the silk screen form plates in advance. In addition, ink adjustment should be made for each color, and also, each of the silk screen form plates should be positioned, among some other operations needed.
Further, the size of the apparatus is large, and it becomes larger in proportion to the number of colors to be used, which requires not only a larger space for installation of the apparatus, but also, it requires a space for storing the silk screen form plates.
Also, with a printing method of the kind, it is possible to perform a large scale production at extremely low costs, but the costs become extremely high if posters should be produced in a smaller lot for a presentation, for a single event, or the like.
Here, therefore, as one of the suitable methods for printing in a smaller lot, an ink jet recording method has been proposed, which enables images to be recorded directly on a recording medium. In accordance with this ink jet recording method, fine ink droplets are discharged from the discharge ports provided for ink jet recording means (an ink jet recording head), and fly onto a recording medium, such as a paper sheet, thus recording images on the recording medium. With this method, it becomes unnecessary to prepare the screen form plates needed for the screen printing as described above. As a result, it is possible to curtail a great number of processes and time needed before the formation of images on the paper sheet. It also becomes possible to make the apparatus much smaller. Also, image information needed for the execution of printing can be stored on a medium, such as a tape, a flexible disc, an optical disc, hence making it possible to provide an excellent storage and reservation of the image information. In addition, there is a great advantage that image processing can be executed easily to change color arrangements, to modify layout, to prepare the enlargement or reduction of sizes, and so on with respect to the original images.
Of the ink jet recording apparatuses, the serial type recording apparatus, which records on a recording medium while executing its main scan in the direction intersecting the conveying direction of the recording medium (that is, the sheet feeding direction or the sub-scanning direction), is capable of recording in a desired area on the recording medium by repeating its operating in such a manner that the sheet feed is executed for a specific amount (the pitch feed to perform the sub-scanning) after the completion of the recording of one-line portion which has been made by recording (main scanning) an image by use of the recording means that travels along the recording medium, and that the recording (main scanning) is made for the next line portion of the image on the recording medium that has come to a stop subsequent to the last pitch feed.
On the other hand, the line type recording apparatus, which is arranged to record on a recording medium only by means of the sub-scanning in the sheet feed direction, records an image in the desired area on the recording medium by setting the recording medium in a specific recording position, and then, the sheet feed (pitch feed) is performed altogether while continuously recording one line portion after another.
In general, the ink jet type recording apparatus (ink jet recording apparatus) is arranged to record on a recording medium by discharging ink from recording means (recording head) to the recording medium, and the recording means (recording head) can be made compact easily for recording images in higher precision at higher speeds. Also, with the ink jet recording apparatus, it is possible to record on an ordinary paper sheet without any particular treatment given to it, which contributes to making its running costs lower. Also, this recording method is of non-impact type, having a lesser amount of noises in operation, among some other advantages such as an easier recording of color images by use of various kinds of ink (color ink, for instance).
Particularly, the ink jet type recording means (recording head) that discharges ink by the utilization of thermal energy is produced by arranging the electro-thermal converting means, electrodes, liquid path walls, a ceiling plate, and the like on a substrate by the application of film formation techniques using the semiconductor process, such as etching, vapor deposition, sputtering, or the like. In this manner, this recording means can be fabricated more compactly and easily with the arrangement of highly densified liquid paths (the arrangement of discharge ports). Also, by the utilization of the IC technologies and techniques, as well as the advantages of the micromachining, it is easier to elongate the recording means or to plane it (make it two dimensional) for the easier provision of fully multiple recording means, and the highly densified assembling thereof as well.
Also, in recent years, there are various demands on the kinds of recording media using different materials. Along with the developments that have been made to meet such demands, it becomes possible for a recording apparatus to use cloth, leather, unwoven stuff, or even metal, in addition to the usual recording medium, such as paper sheet (including thin paper, processed paper sheet) or thin resin plate (OHP or the like).
However, since the ink jet recording apparatus discharges ink from extremely fine discharge port formed on the discharge port surface of the recording head, it is subjected to the adhesion of foreign substances to the discharge port surface, such as solidified ink, paper particles, ink droplets, or the like. (For example, the tail portion of a main droplet becomes a fine droplet due to the surface tension of ink itself when the ink droplet is discharged for the execution of ink jet recording, and then, besides the main ink droplets required for recording, the secondary ink droplets (hereinafter referred to as satellites) or misty ink droplets (hereinafter referred to as mist) is created. The ink droplets that may adhere to the circumference of the ink discharge ports of the recording head are caused by the satellites or mist adhering to it.) The adhesion of such foreign substances may hinder the flight of ink to result in the deviation of impact positions of the ink droplet or to break the ink droplets into splash, or the satellites and mist may clog some of the ink discharge ports, thus causing the defective discharges (or even disabled discharges in some case).
Usually, therefore, an arrangement is made so that the discharge port surface is cleaned periodically or at a specific timing. As to the cleaning of the conventional ink jet recording apparatus, various structures have been disclosed in the specifications of Japanese Patent Laid-Open Application No. 06-340082, Japanese Patent Laid-Open Application No. 07-009674, Japanese Patent Laid-Open Application No. 07-052396, and some others, for example.
FIG. 1
is a view which schematically shows one structural example of a recording head. In
FIG. 1
, the head
2000
has a plurality of nozzles arranged in lines to form the nozzle array
2030
of one color portion. Then, the head unit
600
is
Fukushima Tatsuya
Ikkatai Masatoshi
Sugiyama Toshiro
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Hsieh Shih-Wen
Le N.
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