Riso ScreenFax SP-275 User manual

This manual has been prepared for use on the
NEHOC web site.
By
NEHOC Australia Pty Ltd
ABN 31 000 845 965 Incorporated 1970
PO Box 175, NARRABEEN NSW 2101
Phone [phone] Fax [phone]
E-mail [email protected]
www.nehoc.com.au
RISO SP-275 ScreenFax
SP-275 Installation and Operation Manual
SP-275 V5.1
Section 4

Screen Printing and the RISO Screen System
Screenprintingisamethodforprintingonpaperorcloth. A
screenmadeofsilk,nylonorstainlesssteelmeshisattachedto
aframe. Throughoneofavarietyofmethods, sections of the
screenare treated so thatinkwillpass through while other
sectionspreventink passage. When ink is pressed against the
screenusing a flat rubber-ended tool called asqueegee,the
desired design is printed.
Inthe earlydays of screenprinting, themostcommonly used
screenmaterial was silk,andconsequently this technique is
often called“silk screen printing”. Inrecent years, however, the
mostfrequentlyusedscreen materialshave beennylon,polyes-
ter,orstainlesssteelmesh, rather than silk, sothistechniqueis
nowsimply called“screenprinting”.
Incomparison to other printingmethods,screen printing is
characterisedbyits relative simplicity and the wide range of
applicationsthatarepossible with it. Thanks to itsflexibility,its
usagehadspreadtoawidenumberofdifferentfields.
TheRISO Screen System addstothe advantages of screen
printingby further simplifyingthescreenmaking process –the
mostdifficult step inconventionalscreen printing. The resultis
ascreen printing systemthatis fun foranyoneto use from
absolutebeginners to seasoned professionals.
2. Screen Making Methods
Thereare three basic ways to make a screen: byhand,orbyusing optical or thermal
processes. TheRISO Screen usesthethermalprocess.
ââ
ââ
â Cutting
ââ
ââ
â Blocking
ââ
ââ
â Direct
ââ
ââ
â Indirect
ââ
ââ
â Combined Method
ââ
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â RISO Screen System
By Hand
The Optical Process
The Thermal Process

Features and procedures of the various methods
By Hand
Cutting
Features
Offers very sharp results for simple pictures and lettering.
Procedures
(When using varnished paper)
1) Coat the original with wax, and place it on top of the varnished paper.
2) Cut out the design on the varnished paper with a cutter.
3) Attach the remaining paper to the screen with an iron.
Blocking
Features
Allows for subtle nuances since the design is drawn directly on the screen.
Procedures
(When using paint and sealant)
1) Draw the design directly on the screen with paint
2) Cover the screen with sealant
3) Apply thinner to the paint
The Optical Process
Direct
Features
Since the design is burned directly onto the screen, image sharpness is
limited; it is, however a good method for printing large designs or for high-
volume printing.
Procedure
1) Prepare a film positive of the design
2) Coat the screen with developing solution
3) Attach the positive to the screen and expose it
4) Develop the image by bathing it in water
Indirect
Features
Yields a sharper image that the direct method, but the screen is not as
durable.
Procedures
1) Prepare a film positive of the design
2) Attach the positive to a developing film and expose it
3) Develop the image by bathing it in water
4) When development is complete, affix the developed film to the screen
lCutting
l Blocking
l Direct
l Indirect

Combined Method
Features
Combines the screen durability of the direct method and the image sharp-
ness of the indirect method.
Procedures
1) Prepare film positive of the design.
2) Affix developing film to the screen.
3) Attach the film positive ad expose it.
4) Develop by bathing it in water.
Thermal Process
RISO Screen System
Features
Screen making is quick and easy. Preparing the original is also simple, and
there is no need to work with film positives.
Procedures
1) Draw the design using a carbon-containing writing implement.
2) Lay the design original on the screen and expose it to the flash.
3) Remove the design original.
If you were to draw a design in black on a piece of paper and
then focus a strong light on the paper using a magnifying glass,
smallholeswouldbe burnedintheblackenedsec-
tions. The RISO Screen System uses this prin-
ciple to create a screen master. The film sur-
face of RISO ScreenMasters will shrink rap-
idly if heat is applied. The carbon in the
ink used to draw the design reacts
with the infra-red light in the
flash, concentrating the
light’s heat. Minute holes
(which will allow ink to pass
when printing) are burned
into the screen in a pattern
matchingthe originaldesign.
The principal behind the RISO Screen System
lCombined Method
lRISO Screen System

Features of RISO ScreenMaster
This is another of RISO’s “world first” products – it enables the operator to
produce an imaged screen in a few seconds. More important still is the fact
that the end result is of “high professional quality”.
ââ
ââ
â RISO Screen Master is a lamination of polyester screen mesh and a
specially formulated plastic film and as such is ready for instant processing.
ââ
ââ
â No intermediate processing of artwork is required when using RISO
Screen Master.
· Simply use RISO Artwork Pens on plain white bond paper then process
direct to screen
· Plain paper photocopies and most printing in black from books, magazines
etc., can also be used for artwork
ââ
ââ
â Print “READY” Screens in “LESS THAN 5 MINUTES”
· Actual exposure time is “less that one second”
· The processed screen is then attached to a “RISO Quick Mount Frame”
· These frames are “reusable”
ââ
ââ
â Print Quality
· Matches other screen printing systems
· Superior print quality will be achieved using “RISO Squeegees” especially
developed for the system
ââ
ââ
â Increasingly used by professionals and amateurs alike
· Screen Printers and Sign-makers
· Schools and Colleges of TAFE
· Government Departments both State and Federal
· Small business and hobbyists in the home
· There is a RISO Screen Master System available to suit most applications
ââ
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â RISO Screen Master caters to a wide variety of applications including:
· Textiles, Signs, Posters
· Plastics, Glass and Ceramic Printing
· Glass Etching, Instrument Panels and Printed Circuit Boards
ââ
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â RISO Screen Master will produce one thousand prints from a single
screen and is available in rolls up to a maximum width of 600mm in standard
or fine grade mesh. “Starter Kits” are available.
ââ
ââ
â Completely SAFE, DRY and NON-TOXIC.
· No fumes. No odors. No chemicals
· RISO Screen Master removes the ‘tedium’ from screen printing
ââ
ââ
â It also removes the need for:
Hand cutting stencils, tensioning and stapling screens, coating emulsions
and curing time, camera equipment, processing artwork, darkrooms, chemi-
cals and baths, special lighting, compressors, vacuum frames, pressurised
water, large quantities of screen frames and working space.

IMPORTANT: Artwork for use in RISO systems MUST be carbon based.
ââ
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â Paper must be non-glossy, high or medium grade
ââ
ââ
â Coated papers such as art paper may not be used
ââ
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â Writing instruments must contain carbon.
ââ
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â Original must be thoroughly dried before printing. A damp original
may cause a defective screen/ poor printing results
Artwork can come in many different forms/ types, with each containing a
different levels of carbon. Therefore each type must be prepared accordingly
to provide optimum results.
ââ
ââ
â A computer and laser printer should be used where possible as this
method provides the maximum quality of original artwork
ââ
ââ
â Keep the area where you will be preparing the original clean
ââ
ââ
â Dust and cigarette ash will spoil the original. Do not smoke when
preparing the original because ashes contain carbon and they will therefore
show up when the screen is imaged
ââ
ââ
â If you intend to save the original for a period of time before making the
screen, keep it in an envelope to protect it form dust
The size of the original is ONLY limited by the size of the ScreenMaster
mesh you will be using NOT the screen-making component’s stage (i.e., the
exposure area), as multiple flashes can be made for the one design.
You should take into consideration the screen frame and the area where ink
will build up when calculating the size needed.
There are 4 main types of carbon artwork you can use:
1/ Hand drawn with RISO Carbon Artwork Pens
2/ Photocopied designs - combining different artwork types
3/ Laser Prints from a computer (not bubble/
ink jet)
4/ RISO Artwork Books - off set printed with
carbon ink
Choosing the size of the original
Points to remember while preparing artwork
Artwork Requirements
Artwork types
Artwork Types and Preparation
lThe quality of your print depends
upon the quality of your artwork
lTwo minutes spent preparing your
artwork can save you 20 minutes
in screen/ printing problems
lThe complete SP-275 Operation
Manual details each of the 4 types
of artwork including preparation.
lScreen cutting settings and sum-
mary are listed for each in the Full
operationmanual.

Making a screen with SP-275
The xenon lamp flash interacts with carbon in the original to create heat,
imprinting the screen by opening minute holes in the film surface (on the
screen’s smooth side).
1. Prepare your RISO ScreenMaster for imaging, if required, by cutting to
suite the size of the frame required
~ The screen should cover all the taped area around the frame
2. Place face down over the SP-275 Stage Glass, in the order as pictured
below
3. After placing into the machine,
cover with a piece of plain white
paper to mask the background
4. Lower the Lid of the machine
5. Set the sensitivity adjustment to the
correct setting as determined by the artwork
type you are using (previously outlined Artwork
Types and Preparation)
ââ
ââ
â Remember each form of artwork contains a different level of carbon
and will require a different setting. If you are unsure of the setting, perform a
small test first to determine a suitable setting for your artwork.
Imaging RISO ScreenMaster with SP-275
lRISO Screen Master 135 mesh is
sometimes a little difficult to tell by
feelalone.
lHold the mesh and inspect both
sides. The Matt finish side of the
Screen Master is the mesh side.
lIfthecoveringpadis dirty,smudges
and unwanted marks will be
imprinted.
lPlacingawhitepieceofpaperover
the original will prevent smudging
and unwanted marks from being
transmitted to the screen during
imaging.
lOn humid days, or when the origi-
nalhasthickletters or large blocks
ofshading, set the sensitivityalittle
higher than usual.

6. Switch the selector switch up or down to the setting (PPC or NON- PPC)
to begin powering up the machine.
7. When the electrical
charging process is com-
plete, the green light will
flash and an audible click will
begin. Push the handle down
to ‘flash’ the machine - This
completes the screen imag-
ing process.
8. Before removing the original from the screen, peel back a small corner
of the design to check that the imaging is complete.
9. Peel the original off the screen.
10. Check to see that the glossy film has
been completely removed from the design
areas.
ââ
ââ
â If you have not imaged the design correctly
and film sections remain, write over them with a
RISO Pen (as shown below), lower the sensitivity
setting and expose the screen one more time.
Final Clean-Up
After you have removed your
original from the screen you can
perform the following clean-up
procedure to remove any excess
carbon deposits remaining in the
mesh.
1. Place the screen on the glass stage, rough side down
2. Cover with a piece of Artwork Clean-up Paper (Code S-155).
3. Set the machine to a setting of 5 PPC and ‘flash’ the screen against the
Artwork Clean-up Paper.
4. Remove and discard the Artwork Clean-up Paper.
lImaging is complete if no glossy
spotsremainin the areas on which
the design is drawn.
lIfshiny areascanstill beseenwhen
examining the screen from the
rough side, the screen is not com-
pletelyimaged.
lIncrease the sensitivity setting
slightly and expose the screen
again.
lIf the light sensitivity setting is too
high, there is the danger of a large
hole being burned in the screen.
lThis process will remove traces of
carbon,which remain in the screen
mesh.
lItwillpreventthat ‘blotchy’ appear-
ance of your first test prints.
lItwill maketheset-up and testprint-
ingeasier.
lPlainwhitepapercanalsobeused
When do I increase the setting?
~ General rule is that when 80% or more of the sdesign HAS been
imaged - keep the setting at the same level.
~ If less than 80% has been imaged increase the setting by 0.5-1
NEVER increase by more than 1 in NON-PPC range (no
matter how tempting)

When deciding the
size of your frame, it is
necessary to correctly
position ink reservoirs
(areas at the beginning
and end of the squee-
gee stroke where ink
will collect).
ââ
ââ
â When using thin frames
(such as thin aluminium), allow at
least 3 cm. (1-3/16”) of space at
the beginning and end of the
squeegee stroke, and at least 2
cm. (13/16”) leeway on either
side.
ââ
ââ
â When using thick
frames, allow at least 5 cm.
(2”) at the beginning and end
of the squeegee stroke.
1. Attach double sided tape to the inside of the frame. Be sure not to leave
any uncovered spaces.
~ Plastic frames are available both pre-taped and untaped. Metal frames
are all pre-taped.
ââ
ââ
â DO NOT use foam type
double-sided tapes.
ââ
ââ
â Avoid any double-sided
tape with an ‘aggressive adhe-
sive’, as this will damage the
screen should it have to be
removed for repositioning during
mounting, and also after use of
the screen.
Framing the RISO ScreenMaster
Positioning the ink reservoirs
Framing procedures
lTheRISO ScreenMastermesh can
be attached to the frame either
beforeor after screen making. The
advantagesto attaching thescreen
first are as follows:
lIt is easier to align the screen dur-
ing multi-colour prints.
lAttaching to the frame prevents
curling of the Screen Master, so
that making the screen is easier.
However, note the following:
lTheframe shouldbeno thickerthan
5 mm. (1/4”).
lWhen using a frame smaller than
the screen making component’s
stageglass, the areawithin 1-2 cm.
(7/16”-13/16”)offtheframe’sedge
will not be imprinted.
lSimilarly, the print width should be
approximately 25 mm. (1”) less
than the width of the squeegee.
lRefer to “Maximum Print Size
Table” (in Helpful Hints) as these
dimensionstakethe above factors
into account.
lPrint quality and screen life will be
reduced if the printing area is too
close to edges of the frame.
lRISO plastic frames are supplied
pre-tapedand un-taped.
lWe advise the use of the product
code N-190 for use when taping
framemounts. This tape has been
researched and satisfies the re-
quirements for adhesion and re-
usability.

2. With the rough surface
facing down, attach the screen
to the frame. Start with one of
the two longer sides.
3. In the same way, fix the
middle of the opposite side, and
then attach the whole side while holding the
screen tight.
4. Now fix the two shorter sides, making
sure that you hold the screen
tight.
5. Once you have finished
attaching the screen so that
there are no wrinkles or slack in
the screen surface, rub the
edges with the bottom of a
correction fluid bottle or similar
hard object to make sure that
the screen is securely fixed.
6. Trim off any excess screen
around the outside of the frame.
lWhen planning the size of the
screen,make it slightly larger than
theframe,as this will make mount-
ingeasier.
lAvoid over-stretching the screen -
you will not when this has been
done as plastic frame will bend
lDo not use mechanical framing
devices
lOver tension will reduce the print
life of the screen - remember the
mesh is already pre-tensioned
lIt is best to fix the middle first, then
start at one side and move to the
other.
lWrinkles or slack in the screen will
blur printed images.
lCovering the trimmed areas with
tape will reinforce the screen.