Thermo-engraving machine for printing in relief

A thermo-engraving machine, comprising in combination:

• deposition means for depositing a heat sensitive powder deposit on wet ink of a freshly printed sheet;
• heater means for heating the sheets to melt the powder deposit, the heater means having an entrance and an exit;
• advancing means for continuously advancing the sheets from a printing machine through the heater means;
• and
• cooling conveyor means for cooling the sheets exiting from the heater means and returning the sheets to a vicinity near the entrance of the heater means;
• the cooling conveyor means extending upwardly from the exit of the heater means and curving back to a generally horizontal section located above the heater means that terminates in a receiving tray located generally above the deposition means.

A thermo-engraving machine, comprising in combination:

• deposition means for depositing a heat sensitive powder deposit on wet ink of a freshly printed sheet;
• heater means for heating the sheets to melt the powder deposit, the heater means having an entrance and an exit;
• advancing means for continuously advancing the sheets from a printing machine through the heater means;
• and
• cooling conveyor means for cooling the sheets exiting from the heater means and returning the sheets to a vicinity near the entrance of the heater means;
• the cooling conveyor means comprising;
• a plurality of conveyor belt sections mounted end to end and driven to define a path for the sheets back to the vicinity of the entrance of the heater means;
• and
• blower means for passing air transversely through the conveyor belt sections to cause the sheets to frictionally engage the conveyor belt sections for transport along the path.

In a thermo-engraving machine of the type having deposition means for depositing a powder on wet ink of a freshly printed sheet, heater means for heating the sheets to melt the powder deposit, advancing means for continuously advancing the sheets from a printing machine through the heater means, an improved cooling conveyor means for cooling the sheets exiting the heater means, comprising in combination:

• a conveyor belt assembly having a plurality of driven conveyor belt sections mounted end to end to define a path that extends upwardly from the heater means, then proceeds back over the heater means and terminates above a sheet tray;
• a positive plenum having a discharge wall formed in the configuration of the path and closely spaced from the conveyor belt assembly, with one end located above the entrance of the conveyor belt assembly and another end below the conveyor belt assembly at the sheet tray, the discharge wall and the conveyor belt assembly having a plurality of apertures;
• a negative plenum mounted on the side of the conveyor belt assembly opposite the positive plenum, with the conveyor belt assembly defining one wall of the plenum;
• and
• blower means for blowing air through the apertures in the positive plenum, then through the apertures in the conveyor belt assembly into and out of the negative plenum to cool the sheets and cause them to engage the conveyor belt assembly.

In a thermo-engraving machine of the type having deposition means for depositing a powder on wet ink of a freshly printed sheet, heater means for heating the sheets to melt the powder deposit, advancing means for continuously advancing the sheets from a printing machine through the heater means, an improved cooling conveyor means for cooling the sheets exiting the heater means, comprising in combination:

• a driven conveyor belt assembly beginning at the exit of the heater means and turning back to terminate at a sheet tray in the vicinity of the entrance of the machine;
• plenum means extending along the length of the conveyor belt assembly for passing air transversely through the conveyor belt assembly to cool the sheets and cause them to engage the conveyor belt assembly;
• and
• humidification means for adding moisture to the sheets as they proceed along the conveyor belt assembly.

In a thermo-engraving machine of the type having deposition means for depositing a powder on wet ink of a freshly printed sheet, heater means for heating the sheets to melt the powder deposit, advancing means for continuously advancing the sheets from a printing machine through the heater means, an improved cooling conveyor means for cooling the sheets exiting the heater means, comprising in combination:

• a conveyor belt assembly having a plurality of driven conveyor belt sections mounted end to end to define a path that extends upwardly from the heater means, then proceeds back over the heater means and terminates above a sheet tray;
• a tank containing a liquid mounted at the termination of the conveyor belt assembly;
• and
• roller means having one rotating roller in the liquid in the tank for transferring liquid to the conveyor belt assembly.

In a thermo-engraving machine of the type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, then through heater means for melting the powder, the deposition means comprising:

• a tank through which the material passes;
• and
• at least one vertical partition placed in the tank parallel with the path to divide the tank into at least two separate sections, enabling each section to contain a different type of powder;
• the lower edge of the partition being spaced above the bottom of the tank to enable the material to pass beneath the partition;
• the partition being movable to different lateral positions to vary the widths of the separate sections.

In a thermo-engraving machine of a type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, then through heater means for melting the powder, the deposition means comprising in combination:

• a cyclone powdering assembly of a type that feeds by gravity a metered stream of powder onto the path to cover the printed material with powder, the cyclone powdering assemblyl having recycling suction means for drawing from the path and printed material powder that has not contacted wet ink;
• the suction means having a suction nozzle extending across the path;
• and
• a plurality of disks mounted to a shaft within the nozzle, at least some of the disks having a toothed periphery, the disks being spaced-apart from each other and adapted to rotatably contact the printed material to prevent the printed material from being drawn into the suction means.

In a thermo-engraving machine of the type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, an improved heater means for melting the powder, comprising:

• a housing mounted over the path having an entrance and exit for printed material to pass through;
• the housing having longitudinal sidewalls extending upwardly above the path, defining a heat zone;
• heat source means mounted in the housing for heating the heat zone;
• and
• width varying means for varying the distance between the sidewalls to vary width of the heat zone for printed material of different widths.

In a thermo-engraving machine of the type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, an improved heater means for melting the powder, comprising:

• an insulated heat barrier mounted to the machine over the path, the barrier having an entrance and an exit for printed material to pass underneath the barrier;
• a plurality of longitudinal and parallel heater elements mounted to the lower side of the barrier;
• energizing means for selectively energizing the heater elements individually, so that selected heater elements can be deenergized while others are energized;
• a pair of sidewalls carried longitudinally and parallel by the barrier, defining a heat zone;
• and
• slide means for selectively moving the sidewalls toward and away from each other to vary the width of the heat zone.

In a thermo-engraving machine of the type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, an improved heater means for melting the powder, comprising:

• a housing mounted over the path, the housing having a top and longitudinal sides that define a heat zone within the housing, the housing having an entrance and exit for printed material to pass;
• heat source means in the housing for heating the heat zone;
• the housing being movable between a closed position in close proximity to the path and an open position spaced from the path;
• and
• safety release means for automatically moving the housing from the closed position to the open position should the advancing means cease moving the material.

In a thermo-engraving machine of the type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, an improved heater means for melting the powder, comprising:

• a housing mounted over the path, the housing having a top and longitudinal sides that define a heat zone within the housing, the housing having an entrance and exit for printed material to pass;
• heat source means in the housing for heating the heat zone;
• the housing being movable between a closed position in close proximity to the path and an open position spaced from the path;
• and
• safety release means for automatically moving the housing from the closed position to the open position should the advancing means cease moving the material;
• the safety release means comprising:
• bias means for urging the housing to the open position;
• latch means for releasably securing the housing in the closed position;
• and
• signal means for signaling the latch means to release the housing should the advancing means cease moving the material.

In a thermo-engraving machine of the type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, an improved heater means for melting the powder, comprising:

• a housing mounted over the path, the housing having a top and longitudinal sides that define a heat zone within the housing, the housing having an entrance and exit for printed material to pass;
• heat source means in the housing for heating the heat zone;
• the housing being movable between a closed position in close proximity to the path and an open position spaced from the path;
• and
• safety release means for automatically moving the housing from the closed position to the open position should the advancing means cease moving the material;
• the housing being pivotally secured to the machine at one end to pivot between the closed position in which the housing is horizontal, to the open position in which the housing inclines upwardly;
• and wherein the safety release means comprises:
• bias means for urging the housing to pivot to the open position;
• latch means for releasably securing the housing in the closed position;
• and
• signal means for maintaining the latch means in the closed position only when the signal means is energized.

In a thermo-engraving machine of the type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, an improved heater means for melting the powder, comprising:

• a housing pivotally mounted over the path for movement between a closed position and an open position, the housing having a top and longitudinal sides that define a heat zone within the housing, the housing having an entrance and an exit for the printed material to pass;
• heat source means in the housing for heating the heat zone;
• bias means for urging the oven to the open position;
• latch means movable between a locked position in which it retains the housing in the closed position to an unlocked position in which the housing moves to the open position, the latch means being biased to the unlocked position;
• and
• signal means for moving the latch means to the closed position when the signal means is energized.

In a thermo-engraving machine of the type that has advancing means for advancing freshly printed material from a printing machine along a path through a deposition means for depositing powder on the wet ink, an improved heater means for melting the powder, comprising:

• a housing mounted over the path, the housing having a top and longitudinal sides that define a heat zone within the housing, the housing having an entrance and exit for printed material to pass;
• heat source means in the housing for heating the heat zone.
• pivotal mounting means at one end of the housing for pivoting one end of the housing about an axis transverse to the path from a closed position in close proximity to the path to an open position spaced from the path;
• bias means for urging the housing to the open position;
• and
• latch means for releasably securing the housing in the closed position.