-
Dust spots on Versacamm prints
Hi,
I have a versacamm which seems to develop dust spots on dark printed areas – the lighter areas are perfect.
In the color rip, I have reduced the ink limit to 100 (total per cent), but don’t seem to be able to reduce it further.
I am printing on oracal 3164 and cleaning the material before using it.
It seems to be a problem with the amount of ink being used. Anyone have any ideas how I can correct this?Thanks
-
7 Replies
-
Do not reduce inks to quite that level , in the RIP reduce your total ink at black cut off to about 130 (under colour separation rule)
Some medias dont print well at all , so perhaps try something else , graphityp s22p or X-film (starrex) polymeric print very well.
You can get an anti static gun to zap static too or use an ioniser in the room -
Thanks Rodney.
As usual I new the answer for this type of question would come from you.
The dust spots have virtually dissapeared.
I didn’t higher the total ink per cent, but the print looks great anyway – perhaps I am making a saving too – by using less ink?regards
Clive -
quote :Thanks Rodney.
As usual I new the answer for this type of question would come from you.clive, i was thinking the exact same thing mate 😉 :lol1:
rodney, (now dont laugh 😉 ) but can changing the dot type not help with this also. i is that maybe to prevent flooding rather than dots? i think andrew got something like this recently while testing some vinyl and changing the dot type fixed it? i didnt want to mention this first because i’m new too all this and still very much learning. so didnt want to open my big gobb and be completely wrong 😕 😉
-
Yep , dot types will change that , as will halftone types
If the dots are too close and the media cant hold the inks then the print will run , pool or devlop fisheyes. The way the printer uses the dots it can fire (can only do 7 actual colors) to represent a colour is called the halftone method (sort of , there are other factors involved) there are various ones , the standard has been Digital Mezzotint B , now Precison schoastic screens are being touted. So apart from dot type the screen , the drop size also counts as to ink laydown and then you got to add in the resolution. Low rez actually uses as much ink or maybe a little less then high quality , cos the dots are different
You still have to have the same ink coverage at any resolution to get the olour and ink density.
Using a seperation rule where you can vary the ink loading across all 4 chans or indivdually allows a huge amount of control as to ink laydown , when black prints with K or when it prints with CMYK or if the greyscale print is tinted. Try printing greyscale , the greys should be grey.
If you reduce the ink loading you will reduce ink laydown across the board and use less ink BUT your colours will be screwed. there are other strategies to print “difficult” media such as allowing ink drying time between head passes , slowing speeds down , elevated temp , lighten the graphic , use dry dot instead of variable or variable dry etc. -
thanks for that rodney… very imformative as ever…
does that mean that running on production uses almost same ink as quality? 😕
at the moment we have a infrared heater about 6 foot away from machine pointing directly at prinst coming off.. we have a large spill area that is working well an doesnt generate static as far as we can see. we also have a fan blowing the prints.. so by the time they are coming off they are nice & dry.
not sure if this is a daft questions.. but the grenedier uses 6 diff ink carts, but the cadet, “based on same setup” uses only 4? would it not be lower running costs with the four or am i missing a BIG DUMB print question i should already know by now 😕 :lol1: :lol1: :lol1:
-
thank you rodney i allways have a play with your ideas –
have a look at these spots with a magnifying glass and they are contamination apparantly from the gloss finnish rollers from the factory –
with metamark i can go several mts with out a problem then half a mtr of bad parts all this apart from your own enviroment dust and bad handeling not the first time ive seen a hand prit in the first 300mm of printchris
-
The big diff tween runing low pass and high pass is not really ink usage , tho with pretty gross halftones (ie spots with white between em) you can reduce ink consumption by 30%. however the BIG advantage is speed if you can actually sell the prints at the lowest rez high speed (to ppl with 10% vision who are gazing from 50 m back:)
A fan is a bad idea , its guaranteed to blow dust etc – you can rather move the IR heater.
there is a tweak to turn up the heater temps beyond 50 degrees , to 60 to aid drying , however this does tend to cause buckling etc , so dont do it. You could mount a bar strung with 150 w spots at close intervals on a pulley system just after the front flap , you can lower and raise it as needs be , a cheap way of making a drier. Mr Sticker , I understand your angst , Yeh , we got reall p—d off when printing a huge graphic and all of a sardine things went farming backwards. The roll wasnt continuous , the supplier had joined the 15 m extra needed to make up the 50m roll with masking and sticky tape. Needless to say , we never used that vinyl again.
6 or 4 carts make not much difference robert , barring apparent resolution and tonal shading etc , unless you are ultra fussy , 4 cols will be fine for 99% of all prints , the only thing Lc and LM do is make up a portion of the final print , so perhaps instead of using 90% c , it will use 75%c and 15% Lc (im being real simplistic here – my maths might not add up)
The RIP itself determines how the Lc and LM are used , in our case with the wasatch rip our ink cart useage over time is this
3 magenta to 2 cyan to 1.8 yellow to 1 black to about 1/2 or /13rd LC and LM – others with diff rips report that LC and LM see much higer usage.
I just had a meeting with a supplier who has just come back from several shows and had quite a bit of intersting “gossip” or future trend , future product. – mainly in the larger format area , but he recons to me that industry consensus is that the Roland based machines are definately the class of the field.
I have now got my new flatbed thingy working with absolutely STUNNING results , damn thing beats my Soljet hands down in vibrancy and resolution , the images it prints on various stuff are really “WOW” type things. Im even using it for small signage , printing directlly to Pex etc , best of all , ink costs are about GBP100 a liter vs the 300 we pay and although I wouldnt put the family jewels on the block on this , Im pretty sure that these are ecosol inks (not full solvent) due to the way that act on various substrates compared to the soljet.
The prints are VERY durable. The mngrs supply a coating that costs about 50 quid a litre to make things more ink receptive.
I found a better solution tho not quite as durable , that is artists fixative spray at 3 quid for 3 can (300ml)
Heres something to try for you that wont cause any harm. Get a previously “unprintable” substrate like reflective , lightly coat it with artist fixative spray , allow to dry and then stick it thru the grenadier and be prepared to be sort of amazed at what this coating can do. Now Im pretty sure the grenadier also allows 3 head heights and accepts media up to 1mm thick , try this fixative spray on white rigid ABS with heads set high and heater low or off (it buckles badly with heat). Even tho its only 1mm , im sure there is an extra market somewhere in this for you – POS? Vac forming? , Rigid posters? You can even use a 60 degree blade at max pressure and set it to cut twice (you can set cut passes , like get it to cut over the same stuff again) which scores it deeply enough to break out simple parts.
We tried a cut line that wasnt closed and 3 passes so as to cut right thru and leave a small bridge , but it became messy and parts caught etc.
Log in to reply.