Device for automatically clamping and releasing recording material and operation of said device

An apparatus for automatically clamping film onto a recording drum of a reproduction device and for removing the film exposed by a recording element from the recording drum, comprising:

• the recording drum being arranged in a light-tight space of the reproduction device;
• a peripheral surface of the recording drum having means for vacuum fixing of the film material comprising suction holes, said suction holes being arranged in suction hole rows proceeding substantially parallel relative to an axis of the drum, and the suction hole rows being connected to a stationary vacuum pump;
• a roll film cassette that contains a web of the film as a rotatable film roll and is provided with a slot-shaped film passage opening which closes light-tight, said roll film cassette being receivable into the light-tight space of the reproduction device and means being provided for locking the cassette in said light-tight space, and the film passage opening being aligned toward the recording drum and having a longitudinal extent proceeding substantially parallel to the drum axis;
• a conveying and guide surface means arranged between the film passage opening of the roll film cassette and the recording drum for receiving the film web unwound from the film roll and for guiding the web substantially tangentially relative to the recording drum in a region of the recording drum;
• film conveying means for conveying the film web out of the roll film cassette and to the recording drum;
• film cutting means arranged between the roll film cassette and the recording drum for cutting the film web a film sheet of a prescribed length to be respectively exposed;
• a film length measuring means arranged between the roll film cassette and the recording drum for identifying a length of the film web that has respectively passed therethrough;
• pressure means comprising a pressure roller that is pivotable against the recording drum in a region where a start of the film web conveyed via the conveying and guide surface means to the recording drum comes into contact with the drum surface;
• a positioning drive means for turning the recording drum to start of clamping, start of exposure and start of release positions;
• a lift-off means comprising a lift-off finger pivotable against the recording drum for peeling a respectively exposed sheet of film from the recording drum;
• suction channels proceeding substantially parallel relative to the drum axis in the recording drum, each of said suction channels connecting the suction holes of a suction hole row to one another;
• a vacuum distributor means controllable by rotational motion of the recording drum for connecting each of said suction channels to the stationary vacuum pump via a suction line that during clamping, a suction hole row on which a starting region of the film sheet lies is first charged with vacuum, further suction hole rows are then successively added and charged with vacuum in accordance with increasing wrap of the turning recording drum by the film sheet, and said addition of further suction hole rows occurring in accordance with a respective circumferential length of the film sheet to be clamped on;
• the vacuum distributor means comprising
• a vacuum chamber in the recording drum which is in communication with the stationary vacuum pump via a journal of the recording drum,
• distributor lines between the vacuum chamber and the individual suction channels, said distributor lines proceeding substantially radially relative to the drum axis,
• controllable valve means in the distributor lines for selective opening and closing of the distributor lines, and
• means for controlling the valve means dependent on rotary motion of the recording drum;
• and
• said means for controlling the valve means comprising
• a plate cam seated on a journal of the recording drum and having a control finger means as an actuation element for opening and closing the valve means and which are circularly arranged around the plate cam, and
• an interlock means for blocking the plate cam in a prescribed, stationary position relative to the recording drum, the plate cam being seated on the journal by a slide fit such that the plate cam not blocked by the interlock means is entrained by the journal of the rotating recording drum without slippage.

An apparatus for automatically clamping film onto a recording drum of a reproduction device and for removing the film exposed by a recording element from the recording drum, comprising:

• the recording drum being arranged in a light-tight space of the reproduction device;
• a peripheral surface of the recording drum having means for vacuum fixing of the film material comprising suction holes, said suction holes being arranged in suction hole rows proceeding substantially parallel relative to an axis of the drum, and the suction hole rows being connected to a stationary vacuum pump;
• a roll film cassette that contains a web of the film as a rotatable film roll and is provided with a slot-shaped film passage opening which closes light-tight, said roll film cassette being receivable into the light-tight space of the reproduction device and means being provided for locking the cassette in said light-tight space, and the film passage opening being aligned toward the recording drum and having a longitudinal extent proceeding substantially parallel to the drum axis;
• a conveying and guide surface means arranged between the film passage opening of the roll film cassette and the recording drum for receiving the film web unwound from the film roll and for guiding the web substantially tangentially relative to the recording drum in a region of the recording drum;
• film conveying means for conveying the film web out of the roll film cassette and to the recording drum;
• film cutting means arranged between the roll film cassette and the recording drum for cutting the film web a film sheet of a prescribed length to be respectively exposed;
• a film length measuring means arranged between the roll film cassette and the recording drum for identifying a length of the film web that has respectively passed therethrough;
• pressure means comprising a pressure roller that is pivotable against the recording drum in a region where a start of the film web conveyed via the conveying and guide surface means to the recording drum comes into contact with the drum surface;
• a positioning drive means for turning the recording drum to start of clamping, start of exposure and start of release positions;
• a lift-off means comprising a lift-off finger pivotable against the recording drum for peeling a respectively exposed sheet of film from the recording drum;
• suction channels proceeding substantially parallel relative to the drum axis in the recording drum, each of said suction channels connecting the suction holes of a suction hole row to one another;
• a vacuum distributor means controllable by rotational motion of the recording drum for connecting each of said suction channels to the stationary vacuum pump via a respective suction line that during clamping, a suction hole row on which a starting region of the film sheet lies is first charged with vacuum, further suction hole rows are then successively added and charged with vacuum in accordance with increasing wrap of the turning recording drum by the film sheet, and said addition of further suction hole rows occurring in accordance with a respective circumferential length of the film sheet to be clamped on;
• the recording drum being designed as a hollow cylinder in a wall of which suction channels proceed and said drum having end faces which are closed by disc-shaped covers, at least one of said covers has a central opening;
• an inside surface of at least one of the covers directed into an interior of the drum comprising substantially radially proceeding grooves;
• an outside surface of the at least one cover being provided with bores circularly arranged around the drum axis, said bores discharging into the grooves, and valves being attached to the suction lines;
• a cylindrical housing part secured to the inside surface of the at least one cover and said housing part having its shoulder secured in the central opening of the at least one cover, the grooves in the cover being sealed air-tight by the housing part to form distributor lines connected to the suction channels;
• a groove that comprises a suction bore is secured to said shoulder of the housing part projecting through said opening of the at least one cover;
• an interior of the housing part forming a vacuum chamber that is in communication with the suction bore in a journal via the suction bore in the housing part;
• an end face of the housing part being directed toward the at least one cover comprises circularly arranged bores that connect the vacuum chamber to grooves and that are arranged such that they can be closed by the valves;
• and
• said vacuum distribution means comprising a plate cam seated at a shoulder of the journal and which controls said valves.

An apparatus for automatically clamping film onto a recording drum of a reproduction device and for removing the film exposed by a recording element from the recording drum, comprising:

• the recording drum being arranged in a space of the reproduction device;
• a peripheral surface of the recording drum having means for vacuum-fixing of the film material comprising suction holes distributed over an entire circumference of the recording drum, said suction holes being arranged in suction hole rows proceeding substantially parallel relative to an axis of the drum, and the suction hole rows being connected to a vacuum chamber in an interior of the drum which is connected to a vacuum source via separate distributor lines;
• a roll film cassette that contains a web of the film as a rotatable film roll and is provided with a film passage opening, said roll film cassette being receivable into the space of the reproduction device, and the film passage opening being aligned toward the recording drum;
• guide means arranged between the film passage opening of the roll film cassette and the recording drum for receiving the film web unwound from the film roll and for guiding the web substantially tangentially relative to the recording drum in a region of the recording drum;
• film cutting means arranged between the roll film cassette and the recording drum for cutting from the film web a film sheet of a prescribed length to be respectively exposed;
• a film length measuring means identifying a length of the film web that has respectively passed therethrough;
• pressure means that presses against the recording drum in a region where a start of the film web conveyed via the guide means to the recording drum comes into contact with the drum surface;
• a positioning drive means for turning the recording drum to start of clamping, start of exposure and start of release positions;
• a lift-off means for peeling a respectively exposed sheet of film from the recording drum;
• suction channels in recording drum connected to the suction holes;
• and
• a vacuum distributor means having valves connected between said distributor lines and vacuum source for connecting the suction channels to the vacuum source via said distributor lines in synchronism with rotation of said drum such that during clamping, a suction hole row on which a starting region of the film sheet lies is first charged with vacuum by opening corresponding valve of said suction hole row, further suction hole rows are then successively added and charged with vacuum by opening corresponding valves of said further suction hole rows in accordance with increasing wrap of the turning recording drum by the film sheet, said addition of further suction hole rows occurring in accordance with a respective circumferential length of the film sheet to be clamped on, and for release of said film sheet after exposure, said vacuum distributor means turning off vacuum on a successive row-by-row basis.

A method for automatically clamping film onto a recording drum arranged in a light-tight space of a reproduction device and for releasing the film exposed by a recording element from the recording drum, suction hole rows being provided in a generated surface of the drum which proceed substantially parallel to an axis thereof and which are connectable to a stationary vacuum pump via a suction line, comprising the steps of:

• turning the recording drum with a positioning drive to a start of clamping position, starting a film conveying means and unwinding a film web from a film roll of a roll film cassette and conveying the web via a conveying and guide surface to the recording drum;
• stopping a film conveying means when a start of the conveyed film web lies at a start of clamping position in a region of a pressure roller of a pressure means for pressing a starting region of the film web and in a region of a first suction hole row of the recording drum;
• lowering the pressure roller of the pressure means for pressing a starting region of the film web onto the recording drum;
• charging the first suction hole row with vacuum by a vacuum distributor so as to apply suction in the starting region of the film web;
• starting the film conveying means and a positioning drive for turning the recording drum and conveying further film web to the recording drum;
• while clamping the film web on measuring a length of the film web in means for measuring the film length and stopping the film conveying means as well as the positioning drive when an end of a film sheet of a given length that is to be cut off from the film web lies under a film cutting means for cutting means,
• cutting off the film sheet from the film web by the film cutting means and damping a remaining part of the film sheet with the positioning drive given step-by-step addition of further suction hole rows by a vacuum distributor;
• through a rotation of the drum, and during rotation, successively adding in further suction hole rows by the vacuum distributor and charging the suction hole rows with vacuum in accordance with an increasing wrap of the turning recording drum by the film web, and fixing the film web on the recording drum by the vacuum;
• ending add-in of further suction hole rows by the vacuum distributor in accordance with a respective circumferential length of the film sheet at a suction hole row at which an end region of the film sheet lies, and then lifting off the pressure roller of the pressure means from the recording drum;
• exposing the clamped on film sheet point-by-point and line-by-line by the recording element;
• lowering a nominal value of vacuum provided for the exposure by opening a secondary air valve for a duration of clamping, as a result whereof the film sheet is suctioned on with reduced vacuum;
• measuring an actual value of the vacuum and a reduced actual value for the reduced vacuum with a vacuum gauge, comparing the measured actual values to nominal values, and, if the measured actual values do not reach the nominal values, the film web is conveyed back into the roll film cassette;
• turning the recording drum by the positioning drive into a start of release position after the exposure, and lowering the pressure roller of the pressure means and a lift-off finger of a lift-off means onto the recording drum at the start of release position;
• peeling off the exposed film sheet from the drum surface with the lowered lift-off finger by turning the recording drum;
• and
• disconnecting in turn suction hole rows charged with vacuum when unclamping the film sheet by the vacuum distributor, and turning the recording drum to the start of clamping position.

A method for automatically clamping film onto a recording drum arranged in a light-tight space of a reproduction device and for releasing the film exposed by a recording element from the recording drum, suction hole rows being provided in a peripheral surface of the drum around an entire circumference thereof which proceed substantially parallel to an axis thereof and which are connectable to a vacuum source, comprising the steps of:

• turning the recording drum with a positioning drive to a start of clamping position and unwinding a film web from a film roll of a roll film cassette and conveying the web via a guide surface to the recording drum;
• stopping a film conveying means when a start of the conveyed film web lies at a start of clamping position in a region of for pressing a starting region of the film web and in a region of a first suction hole row of the recording drum;
• lowering the means for pressing a starting region of the film web onto the recording drum;
• charging a first of the suction hole rows only with vacuum by a vacuum distributor so as to suction apply in the starting region of the film web;
• starting the film conveying means and a positioning drive for turning the recording drum and conveying further film web to the recording drum;
• when clamping the film web on measuring a length of the film web in means for measuring the film length and stopping the film conveying means as well as the positioning drive when an end of a film sheet of a given length that is to be cut off from the film web lies under a means for cutting film;
• cutting off the film sheet from the film web by the film cutting means and clamping a remaining part of the film sheet with the positioning drive given step-by-step successive row-by-row addition of further suction hole rows by a vacuum distributor through a rotation of the drum, a corresponding row having vacuum applied only after the web covers over the corresponding row, and during rotation successively adding in further suction hole rows by the vacuum distributor and charging the suction hole rows with vacuum in accordance with an increasing wrap of the turning recording drum by the film web, and fixing the film web on the recording drum by the vacuum;
• ending add-in of further suction hole rows by the vacuum distributor in accordance with a respective circumferential length of the cut film sheet at a suction hole row at which an end region of the film sheet lies, and then lifting off the pressure means from the recording drum;
• exposing the clamped on film by the recording element;
• turning the recording drum by the positioning drive to a start of release position after the exposure, and lowering a means to lift-off the sheet onto the recording drum at a start of release position;
• and
• successively disconnecting suction hole rows charged with vacuum when unclamping the film sheet by the vacuum distributor, and turning the recording drum to the start of clamping position while stripping off the film sheet.