Dyeing And Printing Flashcards
What is the advantage of batch dyeing?
There is uniform colour distribution across the width of the fabric
Explain the process of continuous dyeing.
The fabric is passed through a relatively small pad bath containing the dye and is then squeezed between rubber covered rollers which ensures that a defined quantity of dye is uniformly distributed within and across the fabric
Explain the process of semi-continuous dyeing
The dyebath is applied to the fabric on a pad mangle and the fabric is wound up into a batching roller which can hold a very long length.
How can the dye be fixed in semi continuous dyeing?
Fixation of the dye may be carried out on the batching roller which may be stored in a docking station for several hours at a certain temperature.
What is the main advantage of roller printing?
It produces very sharp outlines to the printed pattern
What determines the maximum design repeat I’m roller printing?
The circumference of the engraved roller
Explain the process of roller printing.
The fabric travels around the large main cylinder
A transfer roller runs partly immersed in paste and in contact with the engraved roller
A doctor blade scrapes away all of the paste except for that contained on the engraving
A cleaning blade on the other side scrapes away any lint picked up from the fabric
The pressure of the engraved roller against the fabric causes the design to be transferred
What is the function of he back grey in roller printing?
It takes up any excess paste which is squeezed through the fabric protecting the blanket and preventing the design from being smeared.
Explain the process of flat screen printing
The fabric is held firm and flat on a conveyor blanket by a tacky adhesive
The conveyor loves over the printing table one screen width at a time
When the fabric stops the screens are lowered into the table and printing paste is supplied to the screens and forced though the patterned areas by a squeegee blade
The screens are then lifted and the next cycle begins with the fabric moving forward one further screen width
Explain the process of rotary screen printing
The printing paste is pumped at a defined rate form the reservoirs to the insides of the cylindrical screens form where t is continuously squeezed through onto the moving fabric by a blade or roller squeegee.
What is the main advantage of rotary screen printing?
It allows continuous production so fabric printing is quicker
What is direct printing?
Where the printing paste is applied directly to the prepared fabric surface
What is overprinting?
Where a plain dyed fabric is printed with a pattern in a darker colour
What is discharge printing?
Where a plain dyed fabric is overprinted won a discharge paste which destroys decolorises or changes the colour of the dye
What is resist printing?
When fabric is printed with a resist paste so that when it is dyed hear printed areas are not coloured
