Printing apparatus with processing tank

An ink jet printing apparatus for producing an image on an ink receiver in response to an in put image, comprising: at least one ink reservoir for providing ink for printing the image; a print head means coupled to an ink receiver and at least one ink reservoir, for disposing ink spots on the ink receiver; and a processing tank coupled to the ink receiver, for providing a fluid for treating the ink spots disposed on the receiver thereby improving the stability, durability and quality of the image.

FIELD OF THE INVENTION 
This invention relates to a apparatus and to a method of improving the 
image stability of the prints provided by ink jet printing. 
BACKGROUND OF THE INVENTION 
In the field of ink jet printing, there have existed long felt needs for 
making images waterfast and also durable against physical abrasion. One 
method practiced in the art is to laminate a clear film on the printed 
image after the image has been printed on a receiver. However, such a 
lamination method is time consuming and often produces undesirable waste 
due to print handling and unusable prints caused by the air bubbles 
trapped between the lamination sheet and the ink receiver. The lamination 
method also increases media and equipment costs because of the additional 
sheet and apparatus involved. 
U.S. Pat. No. 5,635,969 discloses an ink jet printer that includes a print 
head for depositing an ink precursor on the ink recording medium. The ink 
precursor conditions the ink recording medium before colored ink spots are 
placed on the conditioned areas. The preconditioning of the recording 
medium can be used for reducing paper cockle and color bleed, for 
decreasing dry time, and for improving dot shape. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an ink jet apparatus 
that produces prints with improved image stability and durability. It is a 
further object of the present invention to provide such an ink jet 
apparatus that is simple and easy to use. It is a further object of the 
present invention to provide such an ink jet apparatus that operates in a 
time- and energy-efficient manner. 
These objects are achieved by an ink jet printing apparatus for producing 
an image on an ink receiver in response to an in put image, comprising: at 
least one ink reservoir for providing ink for printing the image; a print 
head means coupled to an ink receiver and at least one ink reservoir, for 
disposing ink spots on the ink receiver; a processing tank containing a 
fluid for treating the ink spots disposed on the receiver, thereby 
improving the stability, durability, and quality of the image. 
Images produced by the apparatus and method of the invention are waterfast 
and have good wet adhesion.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention is described with relation to an apparatus that is 
capable of producing an ink jet print and providing a protection fluid on 
the print. 
Referring to FIG. 1, a ink jet printing apparatus 10 is shown to comprise a 
computer 20, ink jet print heads 31-34, ink reservoirs 41-44, a receiver 
transport 70, a platen 90, and a processing tank 40 (shown in FIG. 3a and 
3b). An ink receiver 80 is shown to be supported by a the platen 90. The 
computer 20 can include a microprocessor, a memory, a monitor, a user 
interface, and electronic control of the print heads 31-34. Stored within 
the memory of the computer are image processing programs for color and 
tone conversion, halftoning and so on, which are well known in the art. In 
the present invention, the ink jet printing apparatus 10 can be a 
drop-on-demand ink jet printer that selectively activates the ink jet 
print heads 31-34 to transfer ink drops 100 to produce ink spots 110 in an 
imagewise pattern on the receiver 80. The ink jet printing apparatus 10 
can also be a continuous ink jet printer as is also well known in the art. 
The print heads 31-34 can comprise one or a plurality of ink nozzles. The 
print heads 31-34 can exist in different forms, for example, 
piezo-electric or thermal ink jet print heads. An example of a 
piezoelectric ink jet print head is shown in commonly assigned U.S. Pat. 
No. 5,598,196. 
The print heads 31-34 are labeled K for black ink; C for cyan ink; M for 
magenta ink; and Y for yellow ink. The ink reservoirs 41-44 respectively 
contain black, cyan, magenta, and yellow inks that are supplied to the ink 
jet print heads 31-34 of the corresponding colors. Although not shown in 
FIG. 1, the ink jet printing apparatus 10 can also include print heads and 
reservoirs for other colored inks such as red, green, blue, etc. Several 
ink densities can also be used for each color. The colorants in the inks 
can be dyes or pigments. 
The ink receiver 80 can be common paper having sufficient fibers to provide 
a capillary force to draw the ink from the mixing chambers into the paper. 
Synthetic papers can also be used. The receiver 80 can comprise a layer 
that is porous to the inks, an ink absorbing layer, as well as materials 
with a strong affinity and mordanting effect for the inks. Exemplary 
receivers are disclosed in U.S. Pat. No. 5,605,750. The ink receiver 80 is 
supported by the platen 90. The platen 90 can exist in many forms such as 
a flat platen surface as shown in FIG. 1, or an external or internal drum 
surface. 
FIG. 2 illustrates a top view of the ink jet printing apparatus 10 in 
accordance with the present invention. The ink receiver 80 is transported 
by the receiver transport 70 on the platen 90 in a slow scan direction as 
indicated by an arrow. The receiver transport 70 includes a motor 150 that 
drives a shaft 160 and rollers 170. A plurality of rollers 170 are shown 
for evenly applying forces across the receiver 80. The rollers are 
typically provided with a layer of elastomer material such as polyurethane 
or silicon rubber for providing sufficient friction between the roller 
surface and the receiver 80. The print heads 31-34 are shown to move 
across the receiver 80 in a fast scan direction as indicated by the arrow. 
For clarity, the transport mechanism for the print heads are not shown in 
FIG. 2. A printed image 130 is shown, which is formed by the ink spots 110 
as shown in FIG. 1. 
FIGS. 3a shows a side views of the processing tank 40 when the receiver is 
immersed in the fluid for treatment. FIG. 3b shows a similar side view of 
the processing tank when the receiver is immersed in the fluid for 
treatment. The processing tank 40 includes a tank body 45 that contains a 
protection fluid 50. The protection fluid 50 is preferably colorless. 
The processing tank 40 also includes mechanical components for receiving 
and supporting the receiver 80, and for transporting the protection fluid 
50 in and out of the protection fluid 50. The receiver 80 covered with ink 
spots 110 is supported by a mesh support 200. The mesh support 200 is 
supported by rail supports 220 via connectors 210. The rail supports 220 
are fixed to the bottom surface inside the tank body 45 by bases 230. The 
mesh support 200 can be transported along the rail supports 220 by motor 
240 in the upward and downward direction so that the receiver 80 is moved 
into and out of the protection fluid 50. The motor 240 drives the mesh 
support 200 using a mechanism of belt 250 and pulley 260. The mesh support 
200 is connected to belt 250 through belt connector 270. The motor 240 is 
supported by a motor support 280 such as a column, supported by base 290. 
It will be further appreciated that the present invention is compatible 
with digital printing apparatus other than ink jet printers. These 
printers May include digital silver halide printer, electrophotographic 
printer, and thermal dye transfer printers. A processing containing 
protection fluids such as hardener fluid can be incorporated into these 
printers to enhance the durability and quality of the printed images. 
A typical printing operation is now described. A digital image is input to 
the computer 20. Alternatively, the computer 20 can produce the digital 
image itself. The image is then processed by image processing algorithms 
as described above. The electric signals representing the processed image 
data is ten sent to the print heads 31-34 for driving the print heads for 
ink ejection. During printing, the print heads 31-34 under the control of 
the computer 20 scans along the fast scan direction. The ink receiver 80 
also controlled by the computer 20 is transported by the receiver 
transport 70 along the slow scan direction. The computer 20 controls the 
print heads 31-34 according to the input digital image to eject ink drops 
100 to form ink spots 110 on the receiver 80. To avoid excessive ink on 
the receiver 80, an image area can be printed in a multiple number of 
printing passes by the print heads 31-34. 
After the image is produced on the receiver 80, the receiver 80 is moved to 
the top of the mesh support 200 in the processing tank 40. The computer 20 
subsequently controls the motor 240 to move the mesh support 200 and the 
receiver 80 down into the fluid 50. The receiver 80 with the printed ink 
spots 110 are immersed in the fluid. As described below, the fluid can 
include a hardener solution. The hardener solution hardens the ink spot 
110 on the ink receiver 80 and therefore improves waterfastness and 
physical durability of the printed image. The motor 240 under the control 
of computer 20 then moves the mesh support 200 upward out of the fluid 50. 
The duration of the time when the receiver 80 is immersed in the fluid 50 
can be controlled by computer 20 for the optimum image characteristics. 
The excess fluid on the receiver 80 is then drained off through the meshes 
in the mesh support 200. After drying, the receiver 80 is ready for use by 
the user. 
Inks suitable for the present invention are now described. Inks useful for 
ink jet recording processes generally comprise at least a mixture of a 
solvent and a colorant. The preferred solvent is de-ionized water, and the 
colorant is either a pigment or a dye. Pigments are often preferred over 
dyes because they generally offer improved waterfastness and 
lightfastness. 
Pigmented inks are most commonly prepared in two steps: 
1. a pigment milling step in which the as-received pigment is deaggregated 
into its primary particle size, and 
2. a dilution step in which the pigment mill grind is converted into the 
ink formulation described below. 
Processes for preparing pigmented ink jet inks involve blending the 
pigment, an additive known as a stabilizer or dispersant, a liquid carrier 
medium, grinding media, and other optional addenda such as surfactants and 
defoamers. This pigment slurry is then milled using any of a variety of 
hardware such as ball mills, media mills, high-speed dispersers, or roll 
mills. 
In the practice of the present invention, any of the known pigments can be 
used. The exact choice of pigment will depend upon the specific color 
reproduction and image stability requirements of the printer and 
application. For a list of pigments useful in ink jet inks, see U.S. Pat. 
No. 5,085,698, column 7, line 10 through column 8, line 48. 
The liquid carrier medium can also vary widely and again will depend on the 
nature of the ink jet printer for which the inks are intended. For 
printers which use aqueous inks, water, or a mixture of water with 
miscible organic co-solvents, is the preferred carrier medium. 
The dispersant is another important ingredient in the mill grind. Although 
there are many dispersants known in the art, the choice of the most 
suitable dispersant will often be a function of the carrier medium and the 
type of pigment being used. Preferred dispersants for aqueous ink jet inks 
include sodium dodecyl sulfate, acrylic and styrene-acrylic copolymers, 
such as those disclosed in U.S. Pat. Nos. 5,085,698 and 5,172,133, and 
sulfonated styrenics, such as those disclosed in U.S. Pat. No. 4,597,794. 
Most preferred dispersants are salts of oleyl methyl tauride. 
In the dilution step, other ingredients are also commonly added to the 
formulation for ink jet inks. Cosolvents (0-20 wt %) are added to help 
prevent the ink from drying out or crusting in the orifices of the 
printhead or to help the ink penetrate the receiving substrate, especially 
when the substrate is a porous paper. Preferred cosolvents for the inks of 
the present invention are glycerol, ethylene glycol, propylene glycol, 
2-methyl-2,4,-pentanediol, diethylene glycol, and mixtures thereof, at 
overall concentrations ranging from 5 to 20 wt %. 
A biocide (0.0001-1.0 wt %) can be added to prevent unwanted microbial 
growth which May occur in the ink over time. A preferred biocide for the 
inks of the present invention is Proxel GXL.TM. 
(1,2-benzisothiozolin-3-one, obtained from Zeneca Colours) at a final 
concentration of 0.005-0.5 wt %. 
Other optional additives which May be present in ink jet inks include 
thickeners, conductivity enhancing agents, anti-kogation agents, drying 
agents, and defoamers. 
In the present invention, the protection fluid as described above can 
include an aqueous solution. The aqueous solution can comprise one or more 
cosolvents, a surfactant, and a compound containing a hardening agent such 
as an aldehyde, a blocked aldehyde such as 2,3-dihydroxy-1,4-dioxane 
(DHD), an active olefin or a blocked active olefin and the like would be 
applied to the ink image on receiver 80 by the processing tank 40 as 
described above. Hardeners are defined as any additive which causes 
chemical cross-linking. Blocked hardeners are substances, usually derived 
from the active hardener, that release the active compound under 
appropriate conditions (The Theory of the Photographic Process, 4.sup.th 
Edition, T. H. James, 1977, Macmillan Publishing CO., page 81). 
It is contemplated that other hardening agents May be useful in the instant 
invention. Some compounds known to be effective hardening agents are 
blocked aldehydes such as 2,3-dihydroxy-1,4-dioxane (DHD) and its 
derivatives, acetates of the dialdehydes and hemiacetals, various 
bisulfite adducts, and 2,5-dimethoxytetrahydrofuran. Aldehyde containing 
compounds that are effective hardening agents are also useful in the 
practice of this invention. Some compounds known to be effective hardening 
agents are 3-hydroxybutyraldehyde (U.S. Pat. No. 2,059,817), 
crotonaldehyde, the homologous series of dialdehydes ranging from glyoxal 
to adipaldehyde, diglycolaldehyde (U.S. Pat. No. 3,304,179) and various 
aromatic dialdehydes (U.S. Pat. Nos. 3,565,632 and 3,762,926). Active 
olefin containing compounds that are effective hardening agents are also 
useful in the practice of this invention. In the context of the present 
invention, active olefinic compounds are defined as compounds having two 
or more olefinic bonds, especially unsubstituted vinyl groups, activated 
by adjacent electron withdrawing groups (The Theory of the Photographic 
Process, 4.sup.th Edition, T. H. James, 1977, Macmillan Publishing Co., 
page 82).Some compounds known to be effective hardening agents are divinyl 
ketone, resorcinol bis(vinylsulfonate) (U.S. Pat. No. 3,689,274), 
4,6-bis(vinylsulfonyl)-m-xylene (U.S. Pat. No. 2,994,611), 
bis(vinylsulfonylalkyl) ethers and amines (U.S. Pat. Nos. 3,642,486 and 
3,490,911), 1,3,5-tris(vinylsulfonyl) hexahydro-s-triazine, diacrylamide 
(U.S. Pat. No. 3,635,718), 1,3-bis(acryloyl)urea (U.S. Pat. No. 
3,640,720), N,N'-bismaleimides (U.S. Pat. No. 2,992,109) bisisomaleimides 
(U.S. Pat. No. 3,232,763) and bis(2-acetoxyethyl) ketone (U.S. Pat. No. 
3,360,372). Blocked active olefins of the type bis(2-acetoxyethyl) ketone 
and 3,8-dioxodecane-1,10-bis(pyridinium perchlorate), May also be used. 
(The Theory of the Photographic Process, 4.sup.th Edition, T. H. James, 
1977, Macmillan Publishing CO.) Additional related hardening agents can be 
found in Research Disclosure, Vol. 365, September 1994, Item 36544, II, B. 
Hardeners. 
Still other preferred additives are inorganic hardeners such as aluminum 
salts, especially the sulfate, potassium and ammonium alums, ammonium 
zirconium carbonate, chromium salts such as chromium sulfate and chromium 
alum, and salts of titanium dioxide, zirconium dioxide, and the like. All 
arc employed at concentrations ranging from 0.10 to 5.0 weight percent of 
active ingredients in the solution. 
Combinations of organic and inorganic hardeners May also be used. Most 
preferred is the combination of chrome alum (chromium (III) potassium 
sulfate dodecahydrate) or aluminum sulfate and 2,3-dihydroxy-1,4-dioxane 
(DHD) at total hardener concentrations ranging from 0.10 to 5.0 wt. Most 
preferred is the combination of aluminum sulfate and 
2,3-dihydroxy-1,4-dioxane (DHD) having a total hardener concentration 
ranging between 0.25 and 2.0 weight percent of active ingredients in the 
hardener solution. 
Additional related hardeners can be found in, The Theory Of The 
Photographic Process, 4.sup.th Edition, T. H. James, 1977, Macmillan 
Publishing CO. pages 77-87, and in Research Disclosure, Vol. 365, 
September 1994, Item 36544, II, B. Hardeners. 
It has been unexpectedly found that improved waterfastness, and excellent 
wet adhesion properties on gelatin coatings can be achieved when pigmented 
ink images printed on said coatings are submerged into a solution bath 
containing hardeners such as aldehydes, blocked aldehydes, active olefins 
and blocked active olefins. Most preferred are glyoxal, DHD, and 
formaldehyde, all at concentrations ranging from about 0.10 to 5.0 wt % 
The present invention is better illustrated by the following examples: 
COMATIVE EXAMPLE A (w/o hardener) 
______________________________________ 
Mill Grind 
______________________________________ 
Polymeric beads, mean diameter of 50 .infin.m (milling 
325.0 g 
media) 
Bis(phthalocyanylalumino)tetra-Phenyldisiloxane (cyan 
35.0 g 
pigment) Manufactured by Eastman Kodak 
Oleoyl methyl taurine, (OMT) sodium salt 
17.5 g 
Deionized water 197.5 g 
Proxel GXL .TM.](biocide from Zeneca) 
0.2 g 
______________________________________ 
The above components were milled using a high energy media mill 
manufactured by Morehouse-Cowles Hochmeyer. The mill was run for 8 hours 
at room temperature. An aliquot of the above dispersion to yield 1.0 g 
pigment was mixed with 8.0 g diethylene glycol, and additional deionized 
water for a total of 50.0 g. This ink was filtered through 3-.mu.m filter 
and introduced into an empty Hewlett-Packard 51626A print cartridge. 
Images were made with a Hewlett-Packard DeskJet.TM. 540 printer on medium 
weight resin coated paper containing an imaging layer. 
The resin coated paper stock had been previously treated with a corona 
discharge treatment(CDT) and coated with an imaging layer consisting of 
about 800 mg/ft.sup.2 of gelatin. Poor waterfastness and wet adhesion was 
observed in the D.sub.max areas. In the low density patches (about 0.50), 
and with narrow lines (.about.1/32.sup.nd of an inch) the pigmented ink 
image floated to the surface immediately when immersed in distilled water. 
COMATIVE EXAMPLE B (w/o hardener) 
An ink was prepared in a similar manner as described in Comparative Example 
A. except, the cyan pigment was replaced with 1.45 g of a quinacridone 
magenta pigment (red pigment 122) from Sun Chemical Co. The ink was 
printed as in Comparative Example A and poor waterfastness and wet 
adhesion were observed. 
EXAMPLE 1 
An ink was prepared in the same manner as that described in Comparative 
Example A. This ink was printed on resin coated paper stock which had been 
previously treated with a corona discharge treatment(CDT) and coated with 
an imaging layer consisting of about 800 mg/ft.sup.2 of gelatin. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 2.03 g of 37 
wt % solution of formaldehyde obtained from Aldrich Chemicals to obtain a 
final concentration of 1.50 wt %, and additional deionized water for a 
total of 50.0 g. The overcoat solution was introduced into an empty 
Hewlett-Packard 51626A print cartridge. This solution was overcoated at 
100% coverage on the above pigmented ink image. Excellent waterfastness 
and wet adhesion was observed in the 100% fill areas (D.sub.max). 
Excellent waterfastness and wet adhesion properties were also observed at 
lower density patches, and with thin narrow lines (.about.1/32.sup.nd of 
an inch). 
EXAMPLE 2 
An ink was prepared in the same manner as that described in Comparative Ex. 
B. This ink was printed on resin coated paper stock which had been 
previously treated with a corona discharge treatment(CDT) and coated with 
an imaging layer consisting of about 800 mg/ft.sup.2 of gelatin. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 2.03 g of 37 
wt % solution of formaldehyde obtained from Aldrich Chemicals to obtain a 
final concentration of 1.50 wt %, and additional deionized water for a 
total of 50.0 g. The overcoat solution was introduced into an empty 
Hewlett-Packard 51626A print cartridge. This solution was overcoated at 
100% coverage on the above pigmented ink image. Excellent waterfastness 
and wet adhesion was observed in the 100% fill areas (D.sub.max). 
Excellent waterfastness and wet adhesion properties was also observed at 
lower density patches, and with thin narrow lines (.about.1/32.sup.nd of 
an inch). 
EXAMPLE 3 
An ink was prepared in the same manner as that described in Comparative Ex. 
A. This ink was printed on resin coated paper stock which had been 
previously treated with a corona discharge treatment(CDT) and coated with 
an imaging layer consisting of about 800 mg/ft.sup.2 of gelatin. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 1.25 g of 40 
wt % solution of glyoxal obtained from Aldrich Chemicals to obtain a final 
concentration of 1.0 wt %, and additional deionized water for a total of 
50.0 g. This solution was overcoated on the above pigmented ink image, in 
a manner similar to the above examples. Good waterfastness and very good 
wet adhesion were observed in the 100% fill areas (D.sub.max). Excellent 
waterfastness and wet adhesion properties were also observed in lower 
density patches, and with thin narrow lines (.about.1/32.sup.nd of an 
inch). 
EXAMPLE 4 
An ink was prepared in the same manner as that described in Comparative 
Example B. This ink was printed on resin coated paper stock which had been 
previously treated with a corona discharge treatment(CDT) and coated with 
an imaging layer consisting of about 800 mg/ft.sup.2 of gelatin. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 1.25 g of 40 
wt % solution of glyoxal obtained from Aldrich Chemicals to obtain a final 
concentration of 1.0 wt %, and additional deionized water for a total of 
50.0 g. This solution was overcoated on the above pigmented ink image. 
Excellent waterfastness and very good wet adhesion was observed in the 
100% fill areas (D.sub.max). Excellent waterfastness and wet adhesion 
properties was also observed at lower density patches, and with thin 
narrow lines (.about.1/32.sup.nd of an inch). 
EXAMPLE 5 
An ink was prepared and printed in the same manner as that described in 
Comparative Example A. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 5.00 g of 10 
wt % solution of 2,3-dihydroxy-1,4-dioxane (DHD) obtained from Aldrich to 
obtain a final hardener concentration of 1.00 wt %, and additional 
deionized water for a total of 50.0 g. This solution was overcoated on the 
above pigmented ink image. Very good waterfastness and good wet adhesion 
was observed in the 100% fill areas (D.sub.max). Excellent waterfastness 
and wet adhesion properties was also observed at lower density patches, 
and with thin narrow lines (.about.1/32.sup.nd of an inch). 
EXAMPLE 6 
An ink was prepared and printed in the same manner as that described in 
Comparative Example B. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 5.00 g of 10 
wt % solution of 2,3-dihydroxy-1,4-dioxane (DHD) obtained from Aldrich to 
obtain a final hardener concentration of 1.00 wt %, and additional 
deionized water for a total of 50.0 g. This solution was overcoated on the 
above pigmented ink image. Very good waterfastness and excellent wet 
adhesion was observed in the 100% fill areas (D.sub.max). Excellent 
waterfastness and wet adhesion properties was also observed at lower 
density patches, and with thin narrow lines (.about.1/32.sup.nd of an 
inch). 
EXAMPLE 7 
An ink was prepared and printed as in Comparataive Example A. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 25.00 g of 
2.0 wt % solution of bis-(vinylsulfonyl)-methane ether (BVSME) to obtain a 
final concentration of 1.00 wt %, and additional deionized water for a 
total of 50.0 g. This solution was overcoated on the above pigmented ink 
image. Very good waterfastness and wet adhesion was observed in the 100% 
fill areas (D.sub.max). Excellent waterfastness and wet adhesion 
properties was also observed at lower density patches, and with thin 
narrow lines (.about.1/32.sup.nd of an inch). 
EXAMPLE 8 
An ink was prepared and printed as in Comparative Example B. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 25.00 g of 
2.0 wt % solution of BVSME to obtain a final concentration of 1.00 wt %, 
and additional deionized water for a total of 50.0 g. This solution was 
overcoated on the above pigmented ink image. Excellent waterfastness and 
wet adhesion was observed in the 100% fill areas (D.sub.max). Excellent 
waterfastness and wet adhesion properties was also observed at lower 
density patches, and with thin narrow lines (.about.1/32.sup.nd of an 
inch). 
EXAMPLE 9 
An ink was prepared and printed as in Comparative Example A. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 27.78 g of 
1.80 wt % solution of bis-(vinylsulfonyl)-methane (BVSM) to obtain a final 
concentration of 1.00 wt %, and additional deionized water for a total of 
50.0 g. This solution was overcoated on the above pigmented ink image. 
Excellent waterfastness and very good wet adhesion was observed in the 
100% fill areas (D.sub.max). Excellent waterfastness and wet adhesion 
properties was also observed at lower density patches, and with thin 
narrow lines (.about.1/32.sup.nd of an inch). 
EXAMPLE 10 
An ink was prepared and printed as in Comparative Example A. 
An overcoat solution was prepared consisting of 8.0 g of diethylene glycol, 
5.00 g of a 10.0% solution of Air Products Surfynol.RTM. 465, 27.78 g of 
1.80 wt % solution of BVSM to obtain a final concentration of 1.00 wt %, 
and additional deionized water for a total of 50.0 g. This solution was 
overcoated on the above pigmented ink image. Excellent waterfastness and 
wet adhesion was observed in the 100% fill areas (D.sub.max). Excellent 
waterfastness and wet adhesion properties was also observed at lower 
density patches, and with thin narrow lines (.about.1/32.sup.nd of an 
inch). 
Ink Characterization 
The images printed from the examples and comparative examples were 
evaluated by measuring the optical densities in three area patches with 
maximum ink coverage, using an X-Rite.TM. Photographic Densitometer. The 
average of the three readings is reported. Waterfastness was determined by 
immersing samples of printed images in distilled water for 1 hour and then 
allowing the samples to dry for at least 12 hours. The optical density was 
measured before immersion in water and after immersion in water and 
drying. Waterfastness is determined as the per cent of retained optical 
density after immersion in water and drying. After the samples had been 
immersed in water for half an hour the samples were physically rubbed to 
ascertain if the pigmented ink image would rub off with pressure (wet 
adhesion). This was done on a D.sub.max patch (100% fill), at a 
mid-density point (0.50-1.0), and on narrow lines (.about.1/32.sup.nd of 
an inch). They were subjectively rated based on the following scale: 
excellent=no discernible difference in image density or appearance; very 
good=very slight density loss; good=moderate density loss; fair=image rubs 
off easily; and poor=image floats off surface of paper while immersed in 
water. 
TABLE 1 
__________________________________________________________________________ 
Examples 1-12 are summarized in the following table. 
Hardener % 
Hardener 
Amount 
Density 
Retained 
Wet Adhesion 
Wet Adhesion 
Example 
Receiver 
Pigment 
Type (wt %) 
Before 
Density 
(D.sub.max Patch) 
(Lines + D.sub.min) 
__________________________________________________________________________ 
Comp. A 
gelatin 
cyan 
None None 1.83 
71 Fair Poor 
Comp. B 
gelatin 
p.r. 122 
None None 2.05 
3 Poor Poor 
1 gelatin 
cyan 
FA 1.50 
1.79 
96 Excellent 
Excellent 
2 gelatin 
p.r. 122 
FA 1.50 
2.10 
91 Excellent 
Excellent 
3 gelatin 
cyan 
glyoxal 
1.0 1.89 
82 Good Excellent 
4 gelatin 
p.r. 122 
glyoxal 
1.0 2.03 
101 Very Good 
Excellent 
5 gelatin 
cyan 
DHD 1.0 1.85 
89 Good Excellent 
6 gelatin 
p.r. 122 
DHD 1.0 2.10 
83 Excellent 
Excellent 
7 gelatin 
cyan 
BVSME 
1.0 1.82 
89 Very Good 
Excellent 
8 gelatin 
p.r. 122 
BVSME 
1.0 2.01 
97 Excellent 
Excellent 
9 gelatin 
cyan 
BVSM 1.0 1.83 
97 Very Good 
Excellent 
10 gelatin 
p.r. 122 
BVSM 1.0 1.95 
102 Excellent 
Excellent 
__________________________________________________________________________ 
p.r. = pigment red 
BVSME = bis(vinylsulfonyl)-methane ether 
DHD = 2,3dihydroxy-1,4-dioxane 
BVSM = bis(vinylsulfonyl)-methane 
FA = formaldehyde 
The results indicate that significant enhancement of waterfastness and wet 
adhesion properties of images printed on gelatin, can be achieved when the 
printed image is submerged into aa solution containing hardeners such as 
aldehydes, blocked aldehydes(DHD), active olefins and blocked active 
olefins, and the like. The invention has been described in detail with 
particular reference to certain preferred embodiments thereof, but it will 
be understood that variations and modifications can be effected within the 
spirit and scope of the invention. 
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TS LIST 
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10 ink jet printing apparatus 
20 computer 
31-34 print heads 
40 processing tank 
41-44 ink reservoirs 
50 fluid 
70 receiver transport 
80 ink receiver 
90 platen 
100 ink drop 
110 ink spot 
130 printed image 
150, 240 
motor 
160 shaft 
170 roller 
200 a mesh support 200 
210 connector 
220 rail supports 220 
230, 290 
bases 230 
250 belt 
260 pulley 
270 belt connector 
280 motor support 
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