Printing – Processes – Electric or magnetic transfer
Reexamination Certificate
2002-01-17
2004-08-17
Eickholt, Eugene H. (Department: 2854)
Printing
Processes
Electric or magnetic transfer
C101SDIG029, C399S233000, C399S259000, C399S057000, C355S094000
Reexamination Certificate
active
06776099
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to multi-printer facilities of at least two imaging apparatus (such as printing or copying machines) and in particular, to liquid-toner replenishment systems for multi-printer facilities,
BACKGROUND OF THE INVENTION
Liquid toner for imaging apparatus (such as printing or copying machines) generally contains carrier liquid, toner particles and a minute amount of charge director. Generally, each color of liquid toner is stored in a reservoir from which it is fed to a printing engine for developing images. For good quality printing, proper balance of the three liquid-toner components should be maintained within a narrow band. Depletion of the liquid-toner components is dependent on factors such as the number of prints, the percent of ink coverage of each image and other factors. However, these affect each component differently and each component of the liquid toner depletes at a different rate.
In some prior art systems, replenishment is carried out separately with respect to each component of the liquid toner.
Toner particles are generally replenished in the form of toner concentrate, having a relatively high percentage of particles in liquid carrier. In general, a measurement of the optical density of the liquid toner in the reservoir reveals that the concentration of toner particles has fallen below a predetermined level and that replenishment of toner particles is required.
Carrier liquid is added whenever the liquid toner level in the reservoir falls below a certain level.
Charge director may be added to the toner concentrate. Alternatively or additionally, it may be added to the carrier liquid. Alternatively or additionally, it may be supplied in a separate charge director solution. Charge director is added when the conductivity of the liquid toner is below a predetermined value.
In some systems toner concentrate is replenished from discrete replaceable cartridges, located within the imaging apparatus. Cartridge replacement involves machine down-time and operator attention. Both these factors are costly and inconvenient.
Automatic replenishment of toner concentrate, carrier liquid and charge directors are known.
U.S. Pat. No. 5,231,454, “Charge Director Replenishment System and Method for a Liquid Toner Developing Apparatus,” the disclosure of which is incorporated herein by reference, describes an automatic replenishment system for all three liquid toner components, for single, multicolor, imaging apparatus.
U.S. Pat. No. 4,860,924, “Liquid Developer Charge Director Control,” the disclosure of which is incorporated herein by reference, describes another system of automatic replenishment for all three components of the liquid toner, wherein again, the replenishment system is individual for single, multicolor, imaging apparatus.
U.S. Pat. No. 5,655,194 “Dispenser Apparatus Especially for Liquid Toner Concentrate,” the disclosure of which is incorporated herein by reference, describes apparatus for dispensing liquid-toner concentrate and a container for the liquid-toner concentrate for single, multicolor, imaging apparatus. The system is further described in U.S. Pat. No. 5,558,900 “Liquid Developer System,” and U.S. Pat. No. 5,148,222 “Liquid Developer System,” the disclosures of which are incorporated herein by reference.
Other liquid developer assemblies are described in U.S. Pat. No. 5,557,376, the disclosure of which is incorporated herein by reference.
Exemplary forms of optical density measurement systems (to determine the need for replenishment of toner-concentrate) are shown in U.S. Pat. Nos. 4,579,253; 4,860,924; 5,793,490; and 5,570,193 the disclosures of all of which are incorporated herein by reference.
An exemplary form of conductivity measurement system (to determine the need for replenishment of charge-director solution) is shown in U.S. Pat. No. 4,860,924 the disclosure of which is incorporated herein by reference.
SUMMARY OF THE INVENTION
According to an aspect of some preferred embodiments of the present invention toner is replenished in individual imaging apparatus in a multi-printer facility from a central toner replenishment system.
In some preferred embodiments of the present invention, the central toner replenishment system comprises a central supply system for toner concentrate.
Preferably, where the multi-printer facility is single-color, the central supply system of toner concentrate comprises one tank of toner concentrate and each imaging apparatus has one liquid-toner reservoir. Preferably, where the multi-printer facility comprises multicolor imaging apparatus or a mixture of multicolor and single-color imaging apparatus, the central supply system of toner concentrate comprises as many as four and possible more tanks of toner concentrate, one for each color, and the multicolor imaging apparatus comprises as many as four and possibly more corresponding liquid-toner reservoirs each.
In some preferred embodiments of the present invention, each liquid-toner reservoir is replenished with toner concentrate directly from the central system. Alternatively, each liquid-toner reservoir comprises a toner-concentrate dispenser can which dispenses toner concentrate to the reservoir, on demand. Preferably, the toner-concentrate dispenser can is continuously replenished from the central system.
An aspect of some preferred embodiments of the present invention is that a multi-printer facility of at least two imaging apparatus comprises a central system of carrier liquid, supplying the individual imaging apparatus.
In preferred embodiments according to this aspect, the liquid-toner reservoirs of the imaging apparatus draw the carrier-liquid directly from the central system and have no carrier-liquid reservoirs. Alternatively, each imaging apparatus has its own carrier-liquid reservoir, which is replenished from the central system, on demand, when the level in the apparatus carrier-liquid reservoir falls below a given value.
In some preferred embodiments of the invention, the central system of carrier liquid supplies carrier liquid for cleaning purposes as well. In preferred embodiments, as described below, in which the individual imaging apparatus have no separate liquid-toner reservoirs, carrier liquid from the central system is supplied only for cleaning purposes.
An aspect of some preferred embodiments of the present invention is that a multi-printer facility of at least two imaging apparatus comprises a central liquid-toner system that supplies the liquid-toner working solution to the individual imaging apparatus, as required.
In preferred embodiments of this aspect, the imaging apparatus draw the liquid-toner working solution for each color directly from the central system and have no liquid toner reservoirs themselves.
Preferably, where the multi-printer facility comprises only single-color imaging apparatus, the central system comprises a single reservoir of liquid-toner working solution. Preferably, where the multi-printer facility comprises multicolor imaging apparatus or a mixture of multicolor and single-color imaging apparatus, the central system comprises as many as four or more reservoirs of liquid-toner working solutions, one for each color.
An aspect of some preferred embodiments of the present invention is that replenishment of charge director to a liquid-toner reservoir is made indirectly, on demand, by adding charge director to a carrier-liquid line just prior to replenishment of carrier liquid to a specific reservoir. This aspect is applicable to multi-printer facilities having central systems of liquid toner and carrier liquid as well as to facilities in which carrier liquid is supplied to each local liquid-toner reservoir from a local carrier liquid reservoir.
In preferred embodiments of this aspect, the carrier-liquid flow, for example, of the order of 50 milliliters per replenishment, is used to carry the charge-director, which is minute, for example, of the order of a few milliliters, from the carrier liquid line to the liquid toner reservoir. In addition to assuring that the
Henig Amit
Landa Benzion
Rosen Yosef
Tzori Gilad
Eickholt Eugene H.
Fenster & Company
Hewlett-Packard Indigo B.V.
LandOfFree
Central-ink supply system for multi-printer systems does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Central-ink supply system for multi-printer systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Central-ink supply system for multi-printer systems will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3316082