Electrostatographic apparatus

Claim 2

Electrostatographic apparatus comprising a flexible plate, plate-mounting means including a support member and plate-holding means, the support member having a part-cylindrical support surface defining an axis and the plate-holding means being arranged to hold the plate wrapped on the part-cylindrical surface, drive means arranged to rotate the plate-holding means about the said axis thereby to move the wrapped plate in a circular path concentric with said axis, a plurality of processing stations, including an exposure station and a developer station, disposed round said circular path for passage of the plate sequentially therepast during movement of the plate round said circular path, wherein the plate-holding means is actuable to unwrap the plate from the support surface and hold it in flat condition and the apparatus further comprises actuating means arranged to actuate the plate-holding means and thereby to unwrap the plate and present it in flat condition to the exposure station

Claim 3

Apparatus as claimed in claim 1 and including means for feeding on to the flexible plate, in the wrapped condition thereof, a sheet of material provided with a photosensitive surface layer and constituting an electrostatographic sheet, and means for stripping said sheet from said plate after passage thereof past the said exposure and developer stations.

Claim 4

Apparatus as claimed in claim 1, wherein the plate is an electrostatographic plate provided with a photosensitive layer.

Claim 5

Apparatus as claimed in claim 1, wherein the support member and the plate holding means are mounted for rotation together about the said axis.

Claim 6

Apparatus as claimed in claim 1, wherein the plate has first and second ends disposed parallel to the said axis and the plate-holding means comprises a pair of linkage mechanisms spaced-apart in the axial direction and with the plate disposed between them, each of the said linkage mechanisms being attached to both the first and second ends of the plate and being so arranged that when actuated it unwraps the plate progressively from both ends thereof simultaneously.

Claim 7

Apparatus as claimed in claim 5 and comprising first and second mounting means rotatable about the said axis and having mounted on them the respective linkage mechanisms, the drive means being arranged to rotate the first and second mounting means together.

Claim 8

Apparatus as claimed in claim 6, wherein the support member is in the form of a drum having the support surface as a peripheral part thereof, and wherein the said first and second mounting means are constituted by a pair of drum-end members each secured to the support surface for rotation therewith and each having mounted upon it a respective one of the linkage mechanisms.

Claim 9

Apparatus as claimed in claim 6, wherein each linkage mechanism comprises a linkage member mounted on the respective mounting means for pivotal movement relative thereto, a first linkage arm having a first end pivotally secured to the said one end of the flexible plate for pivotal movement relative thereto and a second end mounted on the said linkage member for pivotal mOvement relative thereto, a second linkage arm having a first end pivotally secured to the said second end of the flexible plate for pivotal movement relative thereto and a second end mounted on the said linkage member for pivotal movement relative thereto, all said pivotal movements being about axes parallel to the axis defined by the support surface and arrangement being such that reciprocating pivotal movement of the said linkage member causes the said first ends of the first linkage arm and of the second linkage arm respectively to lift the said first end and the said second end respectively of the flexible plate off the support surface whilst simultaneously holding the flexible plate in tension and, respectively, to return the said first and second ends of the plate to the support surface.

Claim 10

Apparatus as claimed in claim 8, wherein each said mounting means and the first linkage arm of the respective linkage mechanism mounted thereon are provided with cooperating guiding means which, during pivoting movement of the said linkage member, constrain the said first end of the first linkage arm to move along such a path that the first end of the flexible plate unwraps from and wraps on the support surface without occasioning a difference between the angular rate of movement of the still-wrapped part of the flexible plate round the said circular path and the angular rate of rotation of the first and second mounting means.

Claim 11

Apparatus as claimed in claim 9, wherein the said cooperating guiding means comprises a pin projecting from the first linkage arm in the axial direction of the support surface and a cam-slot plate secured on the mounting means and provided with an appropriately contoured slot, the pin being engaged in said slot for sliding movement therein.

Claim 12

Apparatus as claimed in claim 8, wherein each linkage mechanism further comprises a locking member mounted on the respective mounting means for pivotal movement relative thereto, said locking member and the said linkage member having cooperating locking means which, in one position of the locking member, locks the linkage member against movement from its position in which the flexible plate is wrapped on the drum, there being further provided resilient means urging the locking member into its said one position.

Claim 13

Apparatus as claimed in claim 11, wherein the said locking means comprises a locking pin mounted on the linkage member and a hook provided on the locking member, said hook disengaging said locking pin on pivotal movement of the locking member, against said resilient means, out of its said one position.

Claim 14

Apparatus as claimed in claim 11, wherein the said actuating means comprises a respective fixed cam for each linkage mechanism, and each locking member is provided with cam-follower means which, in the said one position of the locking means, is engaged by the respective fixed cam during rotation of the linkage mechanism about the said axis, thereby to pivot the locking member and release the said linkage member, and wherein each locking member is further provided with engaging means which, on further pivotal movement of the locking member due to the cam, engages and pivots the said linkage member and thereby lifts the ends of the flexible plate off the support surface.

Claim 15

Apparatus as claimed in claim 5, wherein the linkage mechanisms are so arranged and the actuating means is so positioned that the linkage mechanisms, on continued rotation from their actuated position, return due to gravity to their unactuated condition in which the flexible plate is wrapped on the drum.

Claim 16

Apparatus as claimed in claim 8, comprising a first bar and a second bar each extending parallel to the said axis and having secured thereto the said one end and the said second end respectively of the flexible plate, said bars each having two ends which extend beyond the flexible plate in the axial direction, and further comprising a respective anchor link freely pivotally mounted on each said first end of each saiD first linkage arm and of each said second linkage arm, wherein each end of each said bar is releasably secured to a respective one of said anchor links.

Claim 17

Apparatus as claimed in claim 15, wherein the said first and second bars are triangular in cross section and each anchor link is formed with an angular notch in which an end of one of the bars can be snugly accommodated, and wherein each anchor link has a pin extending into said notch and each end of each of said bars has a slot to accommodate and engage said pin thereby to prevent endwise movement of said bars relative to said anchor links.

Claim 18

Apparatus as claimed in claim 15, wherein each said first linkage arm and each said second linkage arm is provided with a respective stop member which, when the linkage mechanisms are in their positions to hold the flexible plate in flat condition, engage and support the respective anchor links mounted on the said arms.

Claim 19

Apparatus as claimed in claim 15, wherein each said first linkage arm and each said second linkage arm is provided at its said first end with a respective locking arm mounted on the respective linkage arm in fixed angular relationship therewith, each said locking arm bearing radially inwards against a respective end of one of said first and second bars, when the linkage mechanisms are in their positions to hold the flexible plate in wrapped condition, and moving clear of said bars as the linkage mechanisms are actuated to move the flexible plate into its flat condition.

Claim 20

Apparatus as claimed in claim 1 and including, in association with the support member, a plurality of flexible plates and a corresponding plurality of plate-holding means each operatively connected with a respective one of the flexible plates and each being actuable individually by the said actuating means during rotation together of the said plurality of plate-holding means about the said axis.