Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
1995-12-08
2002-01-29
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
Reexamination Certificate
active
06341858
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image formation apparatus. More particularly, the invention relates to an image formation apparatus preferably suitable for use of an ink jet recording method. Here, in this respect, recording includes the application of ink (printing) or the like for all the ink supporting members to receive it, such as cloths, threads, papers, sheet materials. The recording apparatus includes every kind of information processing apparatus or printer serving as the output equipment thereof. The present invention is applicable to recording by use of such apparatuses.
2. Related Background Art
The ink jet recording method is to cause droplets of recording liquid to fly and apply them to paper or other recording media for recording.
Generally, however, the main component of ink used for the conventional ink jet recording is water. It also contains water soluble high-boiling point solvents, such as glycol, to prevent ink from being dried or clogging of discharge ports, among other purposes. Therefore, when recording is performed on an ordinary paper using such ink, a sufficient fixation is not obtainable in some cases, and uniform images are not formed sometimes, either, presumably due to uneven distribution of loading material and sizing agent on the surface of a recording paper. Particularly when it is attempted to form color images, colors often spread on the boundaries of images of different colors or mixed unevenly because ink of plural kinds of colors are superposed one after another before each of them is fixed on the paper, thus making the provision of satisfactory images impossible
Therefore, with a view to solving such problems, there is proposed a method, in which before recording ink is discharged, liquid is applied to a recording medium as a processing liquid that makes a good formation of images possible.
For example, a method is disclosed in Japanese Patent Laid-Open Application No. 5-202328, wherein there are used an ink component containing at least chemical dyeing agent having at least one carboxyl group, and a polyvalent metallic salt solvent, and then, the ink component is used to obtain good images on a recording medium subsequent to having applied the polyvalent metallic salt to the recording medium.
Also, in Japanese Patent Laid-Open Application No. 61-75870, there are disclosed an image formation method, a processing liquid, and an ink component used therefor in order to obtain images in good condition.
Then, a method is disclosed in the embodiments of patens filed with the Japanese Patent Laid-Open Application Nos. 5-202328 and 61-75870 to apply the processing liquid to a recording medium by use of a roller before recording is performed by use of an ink jet recording head.
Both of the method and technique thus disclosed are to use an application roller having a length more than the width of a recording medium for the application of the processing liquid to the recording medium in its width direction at a time.
In this method, that is, an application roller having a length more than the width of a recording medium is used for applying the processing liquid in the width direction of the recording medium at a time, the application roller is interlocked with the feeding operation of the recording medium to carry out an overall application of the processing liquid. As a result, although this method is effective, there are still encountered the problems given below.
(1) The application of processing liquid is performed even when a recording medium is not pinched by a pair of rollers. Therefore, the processing liquid is carried on all over the rollers, and when the recording medium is pinched by the rollers, the processing liquid is also applied around to the backside of the recording medium. Hence, not only the processing liquid is used wastefully, but also, it is transferred again to the platen, causing stains together with ink mist.
(2) The location where the processing liquid is applied and the portion where the image data are actually recorded by use of ink are physically apart from each other. As a result, it takes time before the image data are recorded after the processing liquid has been applied. Therefore, the processing liquid is caused to be overly permeated or volatilized, and the degradation of image quality ensues depending on the conformity of the processing liquid and ink containing coloring materials.
(3) When an image is formed by use of ink discharged from a recording head on a jointed portion of processing liquid on the surface of the recording medium (paper), the elapsed time becomes different since the processing liquid has been applied to the locations before and after such joint portion thereof. Therefore, despite ink is discharged simultaneously on the recording medium in the locations before and after such jointed portion, the degrees of permeation of the processing liquid differ before and after the jointed portion on the recording medium. As a result, there occurs difference in the surface density of the effective components that cohere the coloring materials contained in ink on the surface of the recording medium, thus causing the degrees of cohesion of such materials to vary. Consequently, unevenness is brought about in the images to be formed.
(4) The length of the roller should be made more than the width of a recording medium. This presents itself one factor that may hinder making the apparatus smaller.
Also, there are the following problems encountered in using the method, in which the processing liquid is being applied to a recording medium continuously by means of roller or the like that is in contact with the recording medium:
(1) If the processing liquid is applied, preceding ink discharges, to an OHP sheet or the so-called coated paper, that is, a recording medium having an ink receiving layer already formed on its base material, the recorded image is often degraded due to the influence of excessive amount of processing liquid because such medium is prepared in anticipation of the event that ink is directly impacted on the aforesaid ink receiving layer.
(2) When idle rotation is performed to feed or exhaust a recording medium, an excessive amount of processing liquid is applied to the platen unit arranged below the processing liquid application unit, when the processing liquid is applied by use of this unit without presence of any recording medium. As a result, the platen is stained by the adhesion of ink mist, and then, such stain is transferred again to the processing liquid application unit, thus inviting the adhesion of stains to the recording medium or the volume of processing liquid becomes short of the amount good enough to be applied to the anticipated sheet numbers of recording medium.
(3) The apparatus is used as a printer output of a computer or the like, and particularly when a large quantity of data should be transferred for the formation of highly precise color images, for example, there often occurs an interruption of image formation for a long time despite it is still in process because of such data transfer from the computer. Then, if means for applying processing liquid is left intact during such period of interruption, the processing liquid is applied to the recording medium more than necessary to cause the recorded image to be disturbed.
(4) When any defective feed of a recording medium such as the so-called jamming takes place, it is difficult to remove the recording medium if means for applying processing liquid should be left in contact with the recording medium, and the processing liquid is applied wastefully eventually.
Also, the method, in which a processing liquid retainer is provided separately from a recording ink retainer for the intended use, the problems are encountered with respect to refilling the processing liquid as given below.
In other words, even if recorded images become degraded due to the short supply of processing liquid, it is often difficult for the operator to grasp such cause of quality degradation, depe
Barlow John
Brooke Michael S
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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