Image recording apparatus and method

Abstract

Image recording apparatus for recording an image on a recording plate, the apparatus comprising a plate store ( 1 ) for storing a stack ( 12 ) of recording plates separated by interleaved sheets; a drum image scanner ( 6 ) on which recording plates are located for recordal of an image; and a frictional feed apparatus ( 2 ) for withdrawing recording plates from the store ( 1 ) and feeding them singly to the drum image scanner ( 6 ).

We claim:  
     
         1 . Image recording apparatus for recording an image on a recording plate, the apparatus comprising: 
 a plate store for storing a stack of recording plates separated by interleaved sheets;    a drum image scanner on which recording plates are located for recordal of an image; and    a frictional feed apparatus for withdrawing recording plates from the store and feeding them singly to the drum image scanner.    
     
     
         2 . A method of feeding recording plates from a plate store containing a stack of plates with interleaved sheets, to a drum image scanner, the method comprising withdrawing plates from the store and feeding them singly to the drum image scanner all under frictional control.  
     
     
         3 . Frictional feed apparatus for feeding single recording plates or single interleaved sheets from a stack of recording plates and interleaved sheets, to an output position, the apparatus comprising: 
 a nudger member for nudging a plate or sheet in the stack towards a feed location; and    a feed member and cooperating separation member at the feed location for feeding single plates or sheets to the output position;    wherein the contact surfaces of the nudger, feed and separation members are arranged so as to produce sufficient frictional force when in contact with either a plate or a sheet, such that plates or sheets are fed singly towards the output position.    
     
     
         4 . Apparatus according to  claim 3 , wherein the nudger member is a nudger roller.  
     
     
         5 . Apparatus according to  claim 3 , wherein the feed member is a feed roller.  
     
     
         6 . Apparatus according to  claim 3 , further comprising nudger member movement means to move the nudger member from the nudging position to a retracted position.  
     
     
         7 . Apparatus according to  claim 6 , wherein the nudger member movement means comprises a rotatably mounted cam.  
     
     
         8 . Apparatus according to  claim 6 , further comprising stack position sensing means to detect when the nudger member is in the nudging position.  
     
     
         9 . Apparatus according to  claim 3 , further comprising a motor to move the separating member.  
     
     
         10 . Apparatus according to  claim 3 , wherein the separating member further comprises a spring to provide a force to oppose the movement of the separating member.  
     
     
         11 . Apparatus according to  claim 3 , wherein the separating member is a retard pad.  
     
     
         12 . Apparatus according to  claim 11 , wherein the retard pad presents a surface inclined to the feed direction of a plate or sheet.  
     
     
         13 . Apparatus according to  claim 3 , further comprising sensing means positioned downstream of the feed location for detecting if a single plate has been successfully fed.  
     
     
         14 . Apparatus according to  claim 13 , wherein the sensing means is an inductive sensor.  
     
     
         15 . Apparatus according to  claim 13 , wherein the sensing means illuminates the surface of the plate or sheet with radiation and monitors the reflected radiation.  
     
     
         16 . Apparatus according to  claim 13 , further comprising a sheet diverter positioned downstream of the feed location, wherein the sheet diverter is responsive to the sensing means and diverts plates in a first direction and sheets in a second direction.  
     
     
         17 . Apparatus according to  claim 16 , further comprising second sensing means positioned downstream of the sheet diverter in the first direction for detecting if only a single plate has been diverted in the first direction.  
     
     
         18 . Apparatus according to  claim 17  wherein the second sensing means comprises a first radiation source to illuminate the upper surface of the plate or sheet and a first sensor to monitor the reflected radiation, and a corresponding second radiation source and a second sensor positioned to monitor radiation reflected from the lower surface of the plate or sheet.  
     
     
         19 . Apparatus according to  claim 3 , further comprising vacuum cleaning means to clean the nudger member and/or the feed member.  
     
     
         20 . Apparatus according to  claim 19  wherein the vacuum is applied through ducts positioned within the support of the nudger member or the feed member.  
     
     
         21 . Apparatus according to  claim 19 , further comprising a brush attached to the nudger member or the feed member in order to dislodge debris.  
     
     
         22 . A method of withdrawing recording plates or interleaved sheets from a stack of recording plates and interleaved sheets, the method comprising nudging a plate or sheet in the stack towards a feed location using a nudger member and feeding the plate or sheet to an output position using a feed member with a cooperating separating member at the feed location wherein the contact surfaces of the nudger, feed and separation members are arranged so as to produce sufficient frictional force when in contact with either a plate or a sheet, such that plates or sheets are fed singly towards an output position.  
     
     
         23 . A method according to  claim 22 , wherein the method further comprises moving the nudger member away from the nudging position to a retracted position when the plate or sheet is in contact with the feed or separating members.  
     
     
         24 . A method according to  claim 22 , further comprising diverting the plates in a first direction and the interleaved sheets in a second direction.  
     
     
         25 . Plate alignment apparatus for the alignment of a recording plate on a drum of a drum image scanner, the apparatus comprising: 
 an elongate pusher bar extending along the drum and substantially parallel to the cylindrical axis of the drum, wherein the bar has a pusher surface having an elongate axis extending along the bar and substantially parallel with the cylindrical axis, and means for moving the bar in a circumferential manner following the surface of the drum, the elongate axis of the pushing surface remaining substantially parallel to the cylindrical axis, wherein in use, the pusher surface engages with the rearmost edge of a recording plate and urges it to a first position for the recordal of an image.    
     
     
         26 . Apparatus according to  claim 25 , wherein the moving means is adapted to move the bar so as to move the plate from its first position towards a drum exit position.  
     
     
         27 . Apparatus according to  claim 25 , further comprising lateral correction means for correcting the position of a plate in a direction substantially parallel to the cylindrical axis of the drum.  
     
     
         28 . Apparatus according to  claim 25 , further comprising punching means to remove at least one through thickness portion of the recording plate.  
     
     
         29 . Apparatus according to  claim 28 , wherein the punching means comprises a punch indenter which passes through the plate during punching.  
     
     
         30 . Apparatus according to  claim 25 , wherein the moving means comprises pinions mounted to the pusher bar and corresponding tracks mounted upon the drum.  
     
     
         31 . Apparatus according to  claim 25 , further comprising retractable end stops positioned within the drum to abut the leading edge of the recording plate when the plate is located in the first position.  
     
     
         32 . A drum of a drum image scanner for locating recording plates of differing dimensions on the surface of the drum, the surface of the drum on which the plates are located containing a plurality of circumferentially extending axially spaced grooves, wherein each groove contains at least one aperture, all the apertures being connected to a vacuum source whereby all the apertures receive substantially the same vacuum level at all times, the apertures being located such that, when at least part of the length of a groove is covered by a plate, the covered portion contains the aperture or apertures opening into that groove.  
     
     
         33 . Apparatus according to  claim 32 , wherein each groove is closed at one end.  
     
     
         34 . Apparatus according to  claim 32 , wherein each groove contains a single aperture.