GB2306697A

GB2306697A - Plate processing

Info

Publication number: GB2306697A
Application number: GB9522481A
Authority: GB
Inventors: John Pyrah
Original assignee: Horsell Graphic Industries Ltd
Current assignee: Horsell Graphic Industries Ltd
Priority date: 1995-11-02
Filing date: 1995-11-02
Publication date: 1997-05-07
Also published as: GB9522481D0

Abstract

A plate processing apparatus comprises infeed pincer rollers 40, 42, developer bed 44, conveyor pincer rollers 58, 60, a first brush/roller combination 62 which comprises a small diameter roller 64 and large diameter brush roller 66, a second brush/roller combination 70 which comprises a small diameter roller 72 and a larger diameter brush roller 74, a guide table 80 and exit rollers 82, 84. The first brush/roller combination 62 is arranged to drive a trailing edge region of a printing plate which is conveyed, in use, through the apparatus, towards the second brush/roller combination 70 in order to prevent the second brush/roller combination 70 pulling the plate between rollers 64, 66 of the first brush/roller combination 62 which might otherwise cause a visible stripe on the plate.

Description

PLATE PROCESSING This invention relates to plate processing and particularly, although not exclusively, relates to processing apparatus for and a method of processing a printing plate for example a lithographic printing plate.

After light sensitive material on a lithographic printing plate has been exposed, the plate must be developed. If the plate is a positive printing plate, then exposed areas of the plate are rendered less soluble in a developer solution than unexposed areas, whereas if the plate is a negative printing plate, then exposed areas of the plate are rendered more soluble in a developer solution.

Both "single-sided" and "double-sided" printing plates are known. A single-sided plate includes light sensitive material on one side only, whereas a doublesided plate includes light sensitive material on both sides.

Development of a single or double-sided positive or negative plate involves conveying the plate through a bath containing developer solution and brushing the surface or surfaces of the plate to be developed. The brushing of a single surface of a plate is relatively straightforward, whereas brushing both surfaces of a plate is more complex.

A known apparatus for developing a double-sided lithographic printing plate is shown diagrammatically in side elevation in Figure 1. Referring to the figure, the apparatus comprises an infeed table 2 for receiving a plate to be processed and for directing it into a housing 4 of the apparatus. Downstream of the infeed table is a pair of infeed rollers 6 which are arranged to draw the plate to be processed into the housing. The plate is then passed on to a bed 8 with which spray bars 10, 12 are associated. The spray bar 10 is arranged to spray developer liquid at an upwardly facing surface of the plate, whereas spray bar 12 is arranged to fill a V-shaped trough 14 with developer liquid which can contact the downwardly facing surface of the plate.A developer liquid tank 16 is positioned under the spray bars 10, 12 and it extends towards a downstream end 18 of the housing to contain and/or capture developer liquid. The tank 16 is filled with developer liquid up to a level represented by line 20.

Downstream of the bed 8, the plate is directed between two pairs 22, 24 of rotating brushes 25 which are arranged to brush the upwardly and downwardly facing surfaces of the plate in order to aid removal of soluble material from the plate surfaces. The lower brushes of each pair 22, 24 extend into the developer liquid in the bath 16 so that the brushes take up liquid and can transfer it to the downwardly facing surface of the plate.

Downstream of the pair 24 of brushes 25 are spray bars 30, 32 which are arranged to spray developer liquid onto the upwardly and downwardly facing surfaces of the plate for removing any remaining soluble material thereon.

Downstream of the spray bars 30, 32 is a pair of exit rollers 34 which are arranged to direct the plate out of the housing.

In use, infeed rollers 6 and exit rollers 34 rotate with the same surface speed, whereas brushes 25 rotate in the directions of arrows 26, 28 at twenty to thirty times the surface speed of the rollers 6,34. There is a problem with such an arrangement when a trailing edge of a plate being processed is in the region of pair 22 of brushes 25.

In this regard, since the plate is being conveyed by, and at the surface speed of, the exit rollers 34, when the trailing edge is between the pair 22 of brushes 25, there is a tendency for the plate to be urged downstream by the rotating brushes at a greater speed than the surface speed of exit rollers 34. This would cause the trailing edge 36 of the plate 38 to become kinked as shown schematically in figure 2 of the accompanying diagrammatic drawings, which figure shows a trailing edge of a damaged plate.

The above-described problem has been solved in the apparatus of figure 1 by causing the pairs 22, 24 of brushes 25 to automatically reverse as the trailing edge of the plate is disengaged from infeed rollers 6. In this event, exit rollers 34 effectively pull the plate between the pairs 22, 24 of brushes and, accordingly, the plate does not become kinked. However, the solution causes an additional problem in that a mid-region of the plate which is between pairs 22, 24 of brushes 25 at the time of their reversal, is brushed more than other regions of the plate.

This results in a visible stripe of a width "x" (which is equal to the distance between the nips of the pairs 22, 24 of brushes 25) across the mid-region of the plate. This stripe represents an area of better development of the plate which may affect print quality; at the least, it is perceived as a plate defect by printers.

It is an object of the present invention to address problems associated with plate processing.

According to the invention, there is provided processing apparatus for a plate, for example a printing plate, the apparatus comprising: a first combination including a first cleaning means and a first conveying means arranged for the passage of a plate therebetween; and a second conveying means downstream of said first combination and being arranged to convey a plate away from said first combination; wherein said first conveying means is arranged, in use, to drive a trailing edge region of the plate towards said second conveying means.

In the context of this specification, the term "clean" or the like is intended to refer to the removal of any unwanted material from a surface.

In the context of this specification, the term "plate" includes any thin substantially planar member. The term preferably refers to a printing plate, for example a planographic printing plate such as a lithographic printing plate, which includes a substrate having light sensitive material thereon. The substrate may be a metal or mixed metal, aluminium being especially preferred.

Alternatively, the substrate may comprise a synthetic polymeric material, for example a plastics material.

Said first cleaning means is preferably rotatable.

Said first cleaning means is preferably arranged to clean a plate by an abrasive process. Said cleaning means preferably includes an abrasive outer surface. Said cleaning means is preferably arranged to brush the plate in order to clean it. Said cleaning means preferably comprises a rotatable brush means. Said first cleaning means is preferably a roller.

Said first cleaning means is preferably arranged to clean a single surface of the plate which surface is preferably an upwardly facing surface thereof.

Said first cleaning means is preferably arranged to be driven such that its surface speed is greater than the surface speed of said second conveying means. Adjustment means may be provided for adjusting the surface speed of the first cleaning means.

Said first cleaning means may be arranged to be driven at a surface speed which is a least five times, and preferably ten times, the surface speed of the second conveying means.

Said first conveying means is preferably rotatable.

Said first conveying means preferably includes an outer surface made of a friction material arranged so that said conveying means can apply a friction force to a plate for driving the plate towards said second conveying means.

Said friction material is preferably a substantially smooth material. It is preferably rubber or the like.

Said first conveying means is preferably arranged to be driven such that its surface speed is substantially equal to the surface speed of said second conveying means.

To this end, said first conveying means may be operatively connected to said second conveying means. Said first conveying means is preferably a roller.

The diameter of said first conveying means is preferably less, preferably by a factor of at least 0.9, more preferably at least 0.75, than the diameter of said first cleaning means.

Said second conveying means preferably includes a rotatably mounted member. More preferably, said second conveying means Includes two rotatably mounted members arranged for the passage of a plate therebetween.

The apparatus is preferably arranged such that with a plate extending between said first combination and said second conveying means, a surface of the plate is urged towards a conveying surface of said first conveying means.

This ensures that the plate is driven forwards, in use, by the first conveying means rather than the first cleaning means of the first combination and may be achieved by defining a non-linear, for example a curved, travel path for the plate between the first combination and the second conveying means. Said first combination and said second conveying means are preferably arranged such that, in use, said first conveying means abuts a convex surface of a plate being conveyed.

The first ccmbination may be arranged to convey a plate towards said second conveying means in a first direction, whereas the second conveying means may be arranged to convey a plate in a second direction which is angled relative to said first direction. Thus, a curved path may be defined by a plate extending between said first combination and second conveying means.

Where the first combination comprises a first cleaning means and first conveying means in the form of rollers arranged to convey a plate therebetween, and wherein the second conveying means comprises a pair of rollers arranged to convey a plate therebetween, a common tangent of the rollers of the first combination preferably extends at an angle "y" to a common tangent of the roller of the second conveying means. Preferably, 00 < y > 90 .

Preferably, y is greater than 100, more preferably 150.

Preferably, y is less than 60 , more preferably 40". Said common tangent of the rollers of the first combination preferably extends substantially horizontally.

A guide means may be provided for guiding a plate between the first combination and said second conveying means. Said guide means may comprise a substantially planar, preferably inclined surface.

Said apparatus preferably includes a third combination upstream of said first combination. Said third combination is preferably arranged to convey a plate towards said first combination, preferably so that a leading edge of the plate initially contacts said first conveying means of said first combination. This ensures that the leading edge is driven forwards by the first combination at the surface speed of the first conveying means thereof.

Said third combination preferably includes a third cleaning means and a third conveying means arranged for the passage of a plate therebetween.

Said third cleaning means is preferably rotatable.

Said third cleaning means is preferably arranged to clean a plate by an abrasive process. Said cleaning means preferably includes an abrasive outer surface. Said cleaning means is preferably arranged to brush the plate in order to clean it. Said cleaning means preferably comprises a rotatable brush means.

Said third cleaning means is preferably arranged to cleaning a single surface of the plate which surface is preferably a downwardly facing surface thereof.

Said third cleaning means is preferably arranged to be driven such that its surface speed is greater than the surface speed of said second conveying means, suitably by a factor of at least five or preferably at least ten.

Adjustment means may be provided for adjusting the surface speed of the third cleaning means.

Said third conveying means is preferably a roller.

Said third conveying means is preferably rotatable. Said third conveying means preferably includes an outer surface made of a friction material arranged so that said conveying means can apply a friction force to a plate for driving the plate towards said first combination. Said friction material is preferably a substantially smooth material. It is preferably rubber or the like.

Said third conveying means is preferably arranged to be driven so that its surface speed is substantially equal to the surface speed of said second conveying means. To this end, said third conveying means may be operatively connected to said second conveying means.

The apparatus is preferably arranged such that, with a plate extending between said third combination and said first combination, a surface of the plate is urged towards a surface of said third conveying means. This ensures that the plate is driven forwards by the third conveying means rather than the third cleaning means of the third combination and it may be a achieved by defining a nonlinear, for example a curved, travel path between the third combination and the first combination.

Where the third combination comprises a third cleaning means and a third conveying means in the form of rollers and wherein the first combination comprises a first cleaning means and a first conveying means in the form of rollers, a third common tangent to the rollers of the third combination preferably extends at an acute angle to a first common tangent of the rollers of the first combination. Preferably, the first conveying means and said third conveying means are arranged on opposite sides of a boundary line defined by intersecting first and third common tangents.

Said third common tangent preferably extends towards said first conveying means of said first combination.

Said first common tangent preferably extends in an upstream direction towards said third conveying means of said third combination.

The diameter of said third conveying means is preferably less, preferably by a factor of at least 0.9, more preferably at least 0.75, than the diameter of said third cleaning means.

Said apparatus preferably includes a fourth conveying means upstream of said third combination. Said fourth conveying means is preferably arranged to convey a plate towards said third combination. Said fourth conveying means is preferably arranged to be driven at substantially the same surface speed as said second combination.

Said fourth conveying means preferably includes a rotatably mounted member. More preferably, said fourth conveying means includes two rotatably mounted members, for example rollers, arranged for the passage of a plate therebetween.

The outer conveying surface of the first conveying means and/or said second conveying means may have a Shore hardness of less than 50, preferably less than 45, more preferably less than 40. The Shore hardness is preferably at least 20 and, ore preferably at least 25.

Said fourth conveying means is preferably arranged to convey a plate towards said third combination so that a leading edge of the plate initially contacts said third conveying means of said third combination. This ensures that the leading edge is initially driven forwards by the third combination at the surface speed of the third conveying means thereof.

Where the third combination comprises a third cleaning means and a third conveying means in the form of rollers and wherein the fourth conveying means comprises rollers, said third common tangent of the rollers of the third combination preferably extends at an acute angle to a fourth common tangent of the rollers of the fourth conveying means. Said fourth common tangent preferably extends towards said third conveying means.

Said apparatus preferably includes means for contacting a plate with developer liquid. Said means is preferably arranged for contacting both sides of the plate with developer liquid.

The invention extends to a method of processing a plate, preferably a printing plate, which includes conveying the plate between a first cleaning means and a first conveying means of a first combination to a second conveying means and driving a trailing edge region of the plate away from said first combination by means of said first conveying means.

In the method, said first cleaning means preferably rotates in one direction only during passage of the plate.

Preferably, said first conveying means rotates in one direction only during passage of the plate.

Said trailing edge region is preferably driven away from said first combination by, and substantially at the surface speed of, said first conveying means.

The method preferably includes causing the plate to be pressed against the first conveying means as it travels between the first cleaning means and first conveying means. The method may include causing the plate to follow a curved path between said first combination and said second conveying means.

The method preferably includes conveying the plate between a third cleaning means and a third conveying means of a third combination positioned upstream of said first combination. In the method, the plate is preferably directed from said third combination towards said first combination such that a leading edge of the plate initially contacts said first conveying means of said first combination. Preferably, in the method, the plate is caused to be pressed against the third conveying means of the third combination so that a trailing edge region of the plate is driven away from said third combination by, and suitably substantially at the surface speed of, said third conveying means.

In the method, said third cleaning means preferably rotates in one direction only during passage of the plate.

Preferably, said third conveying means rotates in one direction only during passage of the plate.

Preferably, in the method, the leading edge region of the plate is directed towards said third combination such that the leading edge of the plate initially contacts said third conveying means of said third combination.

Said method is preferably carried out using apparatus according to said Invention.

Specific embcdiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 3 is a schematic side elevation of a plate processing apparatus Figure 4 is a schematic exaggerated view of parts of the processing apparatus; Referring to Figure 3, the apparatus comprises an infeed table (not shown) which is arranged to direct a lithographic plate to be processed between a pair of infeed pincer rollers 40, 42. The pincer rollers 40, 42 are arranged to draw the plate into the apparatus and direct it toward a horizontal developer bed 44. Spray bars 46, 48 are positioned on opposite sides of the plate path, upstream of the bed 44 and are arranged to spray developer liquid onto the respective upwardly and downwardly facing surfaces of the plate.

A developer liquid tank 50 includes bottom walls 54 which slope downwardly towards, and are disposed on opposite sides of, a substantially U-cross-section bottom wall region 56, and spaced apart upstanding walls 52, 53.

The tank 50 is arranged to contain and/or capture developer liquid. The maximum filling level of the tank 50 is defined by the height of wall 53.

Downstream of the bed 44, there is provided a pair of conveyor pincer rollers 58,60. The rollers are arranged such that a common tangent to the rollers extends substantially horizontally.

Downstream of the rollers 58, 60 is a first brush/roller combination 62 which comprises a relatively small diameter conveyor roller 64 and a larger diameter brush roller 66. The diameter of roller 64 is selected so that it can be accommodated in the available space. As will be seen from Figure 4, the combination 62 is arranged such that a common tangent 68 to rollers 58, 60 extends towards roller 64 and common tangent 67 of rollers 64, 66 is inclined upwardly at an angle x on moving downstream.

Downstream of the combination 62 is a second brush/roller combination 70 which comprises a relatively small diameter conveyor roller 72 and a larger diameter brush roller 74. Again, the diameter of roller 72 is selected so that it can be accommodated in the available space. As will be seen from Figure 4, the combination 70 is arranged such that the common tangent 67 extends towards roller 72 and common tangent 69 extends substantially horizontally.

Downstream of the combination 70, there is provided a guide table 80 which is inclined upwardly at an angle y, wherein y is about 20", on moving downstream. Above the table 80, a spray bar 81 is provided.

Downstream of table 80, there is provided a pair of exit rollers 82, 84. As will be appreciated from Figure 3, a common tangent 86 to the rollers 82, 84 extends at angle y to the horizontal, but the tangent extends above the level of the outer surface of table 80.

Downstream of exit roller 82, 84 is a roller combination 88 of a downstream processing apparatus.

The infeed rollers 40, ;2, conveyor rollers 58, 60, conveyer rollers 64 and 72 and exit rollers 82, 84 are arranged to rotate such that they have the same surface speed, so that a plate can be conveyed through the apparatus at a constant speed. The speed of the rollers may be adjusted, if required, to adjust the magnitude of the constant speed at which a plate is conveyed through the apparatus. The rollers are arranged to rotate in the directions indicated by arrows 90, 92. Rollers 40, 42, 58, 60, 82 and 84 nay be made of ethylene propylene diene modified (EPDM) rubber having a conventional Shore hardness in the range 35 to 40. Rollers 64, 72 may have a lower Shore hardness in the range 30 to 35. The lower Shore hardness and/or a relatively high coefficient of friction of the rollers 64, 72 increases their grip on a plate being conveyed thereby.

Brush rollers 66, 74 are arranged to rotate in the directions of respective arrows 93, 94. The rollers may be of a conventional design and made of conventional materials. For example, they may be bristle brushes or "plushes" which have an abrasive cleaning surface made of felt or the like. The brushes are arranged to have a variable surface speed which may be set so that they have a surface speed which is significantly greater than the surface speed of the other rollers. For example, the ratio of the surface speed of the brush rollers 66, 74 to that of the conveyor rollers 64, 72 may be varied in the range 11:1 to 68:1.

The apparatus operates as follows.

A plate to be processed is placed on the infeed table (not shown) and then urged between the contrarotating infeed rollers 40, 42. The leading edge of the plate exits the infeed rollers along a path represented by dashed lines 96 and moves towards developer bed 44.

During its passage to the developer bed, spray bars 46, 48 spray developer liquid on opposite sides of the plate.

From the bed 44, the leading edge of the plate is directed between contrarotating conveyor rollers 58, 60.

From rollers 58, 60 the plate travels in a substantially horizontal direction towards the first brush/roller combination 62. The leading edge initially contacts conveyor roller 64 of the combination 62, so that the leading edge is urged forwards by roller 64 (and not by brush roller 66) without any change in speed of the plate.

The relatively high coefficient of friction and/or low Shore hardness is/are believed to aid grip between the plate and roller.

As the plate passes between brush/roller combination 62, the brush 66 brushes the downwardly facing surface of the plate.

From the first roller combination 62, the leading edge of the plate is directed upwardly along the line of common tangent 67 (Figure 4) towards the second roller combination 70. The leading edge initially contacts conveyor roller 72 of the combination 70. There is also a tendency for the plate to be urged towards the roller 72 due to the fact that the plate tries to straighten itself out. When in contact with roller combination 70, the leading edge is urged forwards by roller 72 (and not by brush roller 74) without any change in speed of the plate.

The relatively high coefficient of friction and/or low Shore hardness of roller 72 and/or the tendency for the plate to be urged towards roller 72 are believed to aid the grip of roller 72 on the plate to ensure that the plate is urged forwards by the roller 72 and not by the brush roller 74.

From the second combination 70, the leading edge of the plate moves substantially horizontally until it contacts table 80. It should be appreciated that, when the leading edge of the plate is in contact with table 80, upstream parts of the plate positioned between rollers 70 tend to be urged towards roller 72 due to the tendency for the plate to try to straighten itself out.

From table 80, the leading edge of the plate passes upwardly slightly and passes between contrarotating exit rollers 82, 84.

From exit rollers 82, 84, the plate may be directed into roller combination 88 for downstream processing.

The apparatus is arranged so that the trailing edge of the plate is not driven forwards at any time by brush rollers 66 or 74 in order to avoid kinking or other detrimental effects on the plate. In this regard, as the trailing edge of the plate leaves conveyor rollers 58, 60 it is urged forwards at the surface speed of the rollers.

When the trailing edge is between rollers 64, 66 of the first brush/roller combination, it is urged upwardly towards the conveyor roller 64. This is due to the fact that downstream parts of the plate are between rollers 72, 74 of the second combination 70 and there is, therefore, a tendency for the part of the plate upstream of combination 70 to try to straighten itself by pivoting upwardly. This effect, coupled with the relatively high coefficient of friction and/or low Shore hardness of roller 64, ensures that the roller 64 grips the trailing edge of the plate and urges it forwards at a speed equal to its surface speed. It should be noted that the brush roller 66 does not have an effect in urging the plate forwards.

When the trailing edge is between rollers 72, 74 of the second brush/roller combination 70, it is urged downwardly towards the conveyor roller 72. This is due to the fact that downstream parts of the plate are resting upon table 80 and there is, therefore, a tendency for the part of the plate upstream of the table to try to straighten itself out by pivoting downwardly. Again, this effect, coupled with the relatively high coefficient of friction and/or low Shore hardness of roller 64, ensures that the roller 72 grips the trailing edge of the plate and urges it forwards at a speed equal to its surface speed. Again, it should be noted that the brush roller 74 does not have an effect in urging the plate forwards.

It should now be appreciated that the plate travels through the apparatus at a constant speed. Since brushes 66 and 74 rotate at a substantially constant speed as the plate travels through the apparatus, their brushing action will be substantially constant along the extent of the plate and this will, therefore, lead to consistent development of the plate with no striping of regions thereof. The speed of plate travel and that of the brushes 66, 74 may be adjusted for different plate compositions and/or developer liquid formulations.

The apparatus described can be arranged to develop plates of any typical dimensions. For example, plates having a width up to about 1600 mm; a length of at least 300 mm and a thickness in the range 0.1 mm to 0.6 mm may be developed using the apparatus.

The apparatus described is intended for developing positive or negatIve double-sided lithographic plates, although it could be used for developing single-sided plates. As an alternative for single-side plate development, the apparatus may be arranged to be converted by removing the first and second roller combinations 62, 70 and replacing them with roller combinations specifically arranged for development of single-sided plates. To this end, the roller combination 62, 70 may be mounted on a franework which can be removed from the apparatus and replaced with rollers for single-sided plate development.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMB

1. Processing apparatus for a plate, the apparatus comprising: a first combination including a first cleaning means and a first conveying means arranged for the passage of a plate therebetween; and a second conveying means downstream of said first combination and being arranged to convey a plate away from said first combination; wherein said first conveying means is arranged, in use, to drive a trailing edge region of the plate towards said second conveying means.

2. Apparatus according to Claim 1, wherein said first cleaning means is rotatable.

3. Apparatus according to Claim 1 or Claim 2, wherein said first cleaning means is arranged to be driven such that its surface speed is greater than the surface speed of said second conveying means.

4. Apparatus according to any preceding claim, wherein said first conveying means is rotatable.

5. Apparatus according to any preceding claim, wherein said first conveying means is arranged to be driven such that its surface speed is substantially equal to the surface speed of said second conveying means.

6. Apparatus according to any preceding claim, wherein the diameter of said first conveying means is less than the diameter of said first cleaning means.

7. Apparatus according to any preceding claim, the apparatus being arranged such that with a plate extending between said first combination and said second conveying means, a surface of the plate is urged towards a conveying surface of said first conveying means.

8. Apparatus according to any preceding claim, wherein the first combination is arranged to convey a plate towards said second conveying means in a first direction and the second conveying means is arranged to convey a plate in a second direction which is angled relative to said first direction.

9. Apparatus according to any preceding claim, including guide means in the form of an inclined surface for guiding a plate between said first combination and said second conveying means.

10. Apparatus according to any preceding claim, including a third combination upstream of said first combination which third combination is arranged to convey a plate towards said first combination so that a leading edge of the plate initially contacts said first conveying means of said first combination.

11. Apparatus according to Claim 10, wherein said third combination includes a third cleaning means and a third conveying means arranged for the passage of a plate therebetween.

12. Apparatus according to Claim 10 or Claim 11, the apparatus being arranged such that, with a plate extending between said third combination and said first combination, a surface of the plate is urged towards a conveying surface of said third conveying means.

13. Apparatus according to any of Claims 10 to 12, including fourth conveying means upstream of said third combination which fourth conveying means is arranged to convey a plate towards said third combination.

14. Apparatus according to any of Claims 10 to 13, wherein said fourth conveying means is arranged to convey a plate towards said third combination so that a leading edge of the plate initially contacts said third conveying means of said third combination.

15. Apparatus according to any preceding claim, including means for contacting a plate with developer liquid.

16. A method of processing a plate, which method includes conveying the plate between a first cleaning means and a first conveying means of a first combination to a second conveying means and driving a trailing edge region of the plate away from said first combination by means of said first conveying means.

17. A method according to Claim 16, wherein said first cleaning means rotates in one direction only during passage of the plate.

18. A method according to Claim 16 or Claim 17, wherein said first conveying means rotates in one direction only during passage of the plate.

19. A method according to any of Claims 16 to 18, wherein said trailing edge region is driven away from said first combination by, and substantially at the surface speed of, said first conveying means.

20. A method according to any of Claims 16 to 19, which includes causing the plate to be pressed against the first conveying means as it travels between the first cleaning means and first conveying means.

21. A method according to any of Claims 16 to 20, including causing the plate to follow a curved path between said first combination and said second conveying means.

22. Apparatus substantially as hereinbefore described with reference to Figures 2 to 4 of the accompanying diagrammatic drawings.

23. A method substantially as hereinbefore described with reference to Figures 2 to 4 of the accompanying diagrammatic drawings.