Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-11-24
2001-03-27
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06206497
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid ejection device employing a liquid ejection head for ejecting a liquid, such as an ink or so forth. More specifically, the invention relates to a printing apparatus for performing printing on a printing medium, such as paper, cloth, non-woven fabric, an OHP sheet and so on. The present invention is particularly effective for a printing apparatus which performs printing for a long period or performs continuous printing on a cloth having printing width of 1 m or more. In concrete, the invention is applicable for office use devices, such as a printer, a copy machine, a facsimile and so forth, a mass-production apparatus, such as a textile printing apparatus, a device for driving an article by an ejected liquid, and so forth.
It should be noted that throughout this specification and drawings, the wordings “print” or “record” means not only the operation for adhering ink on a recording medium, such as paper or the like, but also the operation applying an appropriate liquid for a medium in a broader sense, and includes textile printing for applying dye or the like on cloth, and so forth, for example.
2. Description of Related Art
As conventional liquid ejecting devices, there are devices for performing recording by ejecting a liquid or for ejecting a special liquid and utilizing the ejected liquid. In general, since an ejecting portion for ejecting the liquid is quite small, it tends to cause failure of ejection by causing solidification of dye or pigment contained in the liquid or by adhering of foreign matters to make it difficult to effectively use the ejected liquid. For example, in a recording apparatus, failure of ejection of the liquid results in failure of recording. Normally, in order to avoid such problems, forced ejection of the liquid by suction, pressurization or so forth, cleaning of an ejecting region including an ejecting portion, or ejecting gas or liquid to the ejecting portion in the ejecting region is performed at an appropriate intervals as recovery process.
While ejecting liquid to the ejecting portion by a recovering means to solve ink of increased viscosity or solidified ink and so forth, and washing out the adhering matter with the liquid is effective for avoiding failure of ejection, such method may cause sucking of a washing liquid into an ejection nozzle in the vacuum condition to lower ink concentration and thus causes lowering of printing density.
On the other hand, with a recovering means not employing the washing liquid, the ink of increased viscosity may adhere in the vicinity of the nozzle of the ejection head to cause plugging or ink ejection failure.
Moreover, in the case where the liquid is forcedly discharged from the ejecting portion by sucking, if the ejection head having a plurality of ejection nozzles is employed, an internal volume of a cap to be tightly fitted to the ejection head upon suction becomes large to make vacuum control difficult.
Also, in the method simply contacting a sponge onto the ejection head, if the ejection nozzle with a fine nozzle, such as for 400 dpi, it possibly causes foreign matters to be pushed into the nozzle resulting in causing failure.
Furthermore, in order to avoid accumulation of a mist splashing upon ejection of the ink on the surface of the head to block the ejecting orifice to cause ejection failure or to make ejection impossible (referred to as wet non-ejection), it may be considered to wipe off the surface of the head by a blade. However, when industrial operation is continued for a long period, the wiped ink may have no way to be discharged and thus accumulated and increase viscosity. Therefore, the ejection head may be wiped with the blade on which the high viscous ink is adhering to increase possibility of causing ejection failure. Particularly, in the case of a color recording apparatus, mists from four heads can be collected to make this problem, significant.
In addition, since the head and the wiping means are repeatedly worn, it is desired to take a measure for avoiding shortening of the life. Also, it is desired to perform wiping process efficiently to improve throughput in printing operation.
Furthermore, in the construction where a blade formed of an absorbing body is employed, if ejecting operation or wiping operation is not performed for a long period, or the apparatus body is rested for a long period, the blade may be dried completely so that desired wiping effect cannot be achieved and may affect to the ejecting surface of the head by the wiping operation.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a liquid ejecting apparatus for ejecting a predetermined liquid enjoying a liquid ejection head, comprises:
wiping means for wiping a surface of the liquid ejection head through which the liquid is ejected; and
means for varying a wiping condition of the surface of the liquid ejection head by the wiping means.
The liquid ejecting apparatus may further comprise means for varying the wiping condition during operation of the liquid ejecting apparatus.
The wiping means may include porous material blade.
The liquid ejecting apparatus may further comprise cleaning means for cleaning the wiping means, the cleaning means including liquid ejecting means for ejecting a washing liquid to the wiping means.
The cleaning means may include liquid sucking means for sucking liquid from the wiping means.
The liquid ejection heads may be reciprocated, and the means for varying the wiping condition may vary wiping direction relative to the liquid ejection head.
The liquid ejection heads may be reciprocated, and the means for varying the wiping condition may vary wiping direction relative to the liquid ejection head.
Before recording operation of the liquid ejecting apparatus, the wiping direction may be reciprocating traveling directions of the liquid ejection head, and during recording, the wiping direction may be a reversed traveling direction of the liquid ejection head.
The wiping condition to be varied may be a rotative wiping speed between the wiping means and the liquid ejection head.
The liquid ejection head may be reciprocated and the means for varying the wiping condition may vary a relative wiping speed between the wiping means and the liquid ejection head.
The wiping speed before recording operation of the liquid ejecting apparatus may be lower than that in the wiping speed during recording.
The wiping condition to be varied may be a penetration amount of the wiping means into the liquid ejection head.
The liquid ejection head may be reciprocated, and the wiping condition to be varied may be a penetration amount of the wiping means into the liquid ejection head.
The relative penetration amount before the recording operation of the liquid ejecting apparatus may be greater than that upon recording.
The wiping condition to be varied may be a content of a washing liquid of the wiping means.
The liquid ejection head may be reciprocated, and the wiping condition to be varied may be a content of a washing liquid of the wiping means.
The washing liquid content before recording operation of the liquid ejecting apparatus may be greater than that upon recording.
The wiping condition to be varied may be frequency of contact of the wiping means and the liquid ejecting surface.
The liquid ejection head may be reciprocated, and the wiping condition to be varied may be frequency of contact of the wiping means and the liquid ejecting surface.
The contacting frequency before recording operation of the liquid ejecting apparatus may be higher than that upon recording.
The liquid ejecting apparatus may comprise, as recovery means for maintaining good ejecting condition of the liquid ejection head, means for performing a process employing the wiping means, means for performing a process employing the wiping means and pressurizing an ink supply system, and means for performing ejection of ink through the liquid ejection head for other than printing, and means for varying proces
Kurata Mitsuru
Mabuchi Toshiaki
Miura Yasushi
Takanaka Yasuyuki
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Le N.
Nghiem Michael
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