Methods and Means Relating to Photopolymer Printing Plates

A method for feeding a photopolymerised elastomeric printing plate, subsequent to exposure and washing out thereof, along a path through a rinsing station, which method comprises:

• optionally providing a plate assembly comprising the plate and, supporting the plate, a carrier having a pair of opposed peripheral regions each extending laterally beyond respective opposed lateral edge regions of the plate,
• providing, transversely of the path, at least one pair of driven rollers (8, 13) defining a nip therebetween through which the plate can pass so as to be forwarded along the path by frictional engagement of the plate or plate assembly with each of the driven rollers within the nip, at least one of which rollers is profiled so as
• (a) to allow contact of the profiled roller with the opposed lateral edge regions of the plate or, when provided, corresponding opposed peripheral regions of the plate assembly, thereby to allow the said frictional engagement, but
• (b) to allow freedom from contact of the plate with the or each profiled roller at an interior region of the plate between the said regions in contact with the or each profiled roller, and
• feeding the plate, or optionally when provided, the plate assembly, by the driven rollers along the path through the rinsing station.

Apparatus for feeding a photopolymerised elastomeric printing plate, subsequent to exposure and washing out thereof, along a path through a rinsing station, which apparatus comprises:

• a rinsing station for rinsing the plate,
• at least one pair of drivable rollers (8, 13) defining a nip therebetween through which the plate can pass to allow the plate to be forwarded along the path by frictional engagement of the plate, or of a plate assembly including the plate, with each of the rollers within the nip, wherein the plate assembly, when provided, comprises the plate and, supporting the plate, a carrier having a pair of opposed peripheral regions, each extending laterally beyond respective opposed lateral edge regions of the plate,
• and wherein at least one of which rollers is profiled so as
• (a) to allow contact of the profiled roller with the opposed lateral edge regions of the plate, or, when provided, corresponding opposed peripheral regions of the plate assembly, thereby to allow the said frictional engagement, but
• (b) to allow freedom from contact of the plate with the or each profiled roller at an interior region of the plate between the said regions in contact with the or each profiled roller.

A method for processing a pre-exposed photopolymerised elastomeric printing plate comprising the steps of:

• washing out the plate, subsequent to exposure thereof, comprising the step of subjecting the plate to a flow of wash-out fluid and allowing the wash-out fluid to flow through a filtration unit after its contact with the plate, wherein the filtration unit houses a wire sieve such that wash-out fluid flowing thorough the filtration unit flows through the sieve;
• and
• rinsing the plate by a method for feeding a photopolymerised elastomeric printing plate, subsequent to exposure and washing out thereof, along a path through a rinsing station, which method comprises:
• optionally providing a plate assembly comprising the plate and, supporting the plate, a carrier having a pair of opposed peripheral regions each extending laterally beyond respective opposed lateral edge regions of the plate,
• providing, transversely of the path, at least one pair of driven rollers (8, 13) defining a nip therebetween through which the plate can pass so as to be forwarded along the path by frictional engagement of the plate or plate assembly with each of the driven rollers within the nip, at least one of which rollers is profiled so as
• (a) to allow contact of the profiled roller with the opposed lateral edge regions of the plate or, when provided, corresponding opposed peripheral regions of the plate assembly, thereby to allow the said frictional engagement, but
• (b) to allow freedom from contact of the plate with the or each profiled roller at an interior region of the plate between the said regions in contact with the or each profiled roller, and
• feeding the plate, or optionally when provided, the plate assembly, by the driven rollers along the path through the rinsing station.

Apparatus according to claim 20, additionally comprising the apparatus for feeding a photopolymerised elastomeric printing plate, subsequent to exposure and washing out thereof, along a path through a rinsing station, which apparatus comprises:

• a rinsing station for rinsing the plate,
• at least one pair of drivable rollers (8, 13) defining a nip therebetween through which the plate can pass to allow the plate to be forwarded along the path by frictional engagement of the plate, or of a plate assembly including the plate, with each of the rollers within the nip, wherein the plate assembly, when provided, comprises the plate and, supporting the plate, a carrier having a pair of opposed peripheral regions, each extending laterally beyond respective opposed lateral edge regions of the plate,
• and wherein at least one of which rollers is profiled so as
• (a) to allow contact of the profiled roller with the opposed lateral edge regions of the plate, or, when provided, corresponding opposed peripheral regions of the plate assembly, thereby to allow the said frictional engagement, but
• (b) to allow freedom from contact of the plate with the or each profiled roller at an interior region of the plate between the said regions in contact with the or each profiled roller.

Apparatus for processing a pre-exposed photopolymerised elastomeric printing plate, which apparatus comprises:

• apparatus for washing out the plate comprising a source of wash-out fluid, means for supplying fluid from the source of wash-out fluid to a plate positioned in the apparatus, means for allowing fluid to flow to a filtration unit after contact with the plate, and a filtration unit, wherein the filtration unit houses a wire sieve such that wash-out fluid flowing through the filtration unit flows through the sieve;
• and
• apparatus for rinsing station for rinsing the plate,
• at least one pair of drivable rollers (8, 13) defining a nip therebetween through which the plate can pass to allow the plate to be forwarded along the path by frictional engagement of the plate, or of a plate assembly including the plate, with each of the rollers within the nip, wherein the plate assembly, when provided, comprises the plate and, supporting the plate, a carrier having a pair of opposed peripheral regions, each extending laterally beyond respective opposed lateral edge regions of the plate,
• and wherein at least one of which rollers is profiled so as
• (a) to allow contact of the profiled roller with the opposed lateral edge regions of the plate, or, when provided, corresponding opposed peripheral regions of the plate assembly, thereby to allow the said frictional engagement, but
• (b) to allow freedom from contact of the plate with the or each profiled roller at an interior region of the plate between the said regions in contact with the or each profiled roller.

A method for processing a pre-exposed photopolymerised elastomeric printing plate, having washed out the plate subsequent to exposure thereof, which method comprises the steps of:

• (a) rinsing the plate in a rinsing station;
• and
• (b) subjecting the plate to post-exposure and detack in a post-exposure station;
• wherein the surface of the plate is subjected to a first jet of air before step (a) and to a second jet of air after step (a) but before step (b), wherein the jet of air is directed onto the surface of the plate, and wherein the first jet of air acts as a barrier between the wash-out station and the printing station to prevent ingress of debris-containing wash-out water and the second jet of air acts a barrier between the rinsing station and post-exposure station to substantially prevent rinsing fluid entering the post-exposure station.

Apparatus for processing a pre-exposed photopolymerised elastomeric printing plate, having washed out the plate in a wash-out station subsequent to exposure thereof, comprising:

• (a) a rinsing station for rinsing the plate;
• (b) a post-exposure station for subjecting the plate to post exposure and detack;
• (c) a first air blower located between the wash-out station and the rinsing station;
• and
• (d) a second air blower located between the rinsing station and the post-exposure station,
• wherein each air blower (c) and (d) is capable of blowing a jet of air onto the surface of the plate, the first air blower thereby acting as a barrier to prevent ingress of debris-containing wash-out water into the rinsing station and the second air blower thereby acting as a barrier to substantially prevent rinsing fluid entering the post-exposure station.

Apparatus for processing a pre-exposed photopolymerised elastomeric printing plate, having washed out the plate in a wash-out station subsequent to exposure thereof, comprising a post-exposure station for subjecting the plate to post exposure and detack, wherein the post-exposure station comprises:

• (a) a UV light source
• (b) a quartz glass panel;
• and
• (c) means for locating a plate in the post-exposure station;
• wherein the quartz glass panel is positioned between the UV light source and the means for locating a plate in the post-exposure station, such that UV light passes through the quartz glass panel before contacting a plate located in the post-exposure station.