There is disclosed a method of printing onto the surface of a substrate, which method comprises i) coating a donor surface with a monolayer of particles, ii) treating the substrate surface to render at least selected regions tacky, and iii) contacting the substrate surface with the donor surface to cause particles to transfer from the donor surface only to the tacky regions of the substrate surface. After printing on a substrate, the donor surface returns to the coating station where the continuity of the monolayer is restored by recovering with fresh particles the regions of the donor surface exposed by the transfer of particles to the substrate.

There is disclosed a method of printing onto the surface of a substrate, which method comprises i) coating a donor surface with a monolayer of particles, ii) treating the substrate surface to render at least selected regions tacky, and iii) contacting the substrate surface with the donor surface to cause particles to transfer from the donor surface only to the tacky regions of the substrate surface. After printing on a substrate, the donor surface returns to the coating station where the continuity of the monolayer is restored by recovering with fresh particles the regions of the donor surface exposed by the transfer of particles to the substrate.

A coating booth (101) for elements to be coated. The coating booth (101) comprises a passage between opposing vertical sides (107a, 107b, 108a, 108b) through which elements to be coated are conveyed. There is an entrance (105) at one end of the passage and an exit (106) at the other end of the passage. The coating booth (101) comprises a conveyor line (102) for supporting said elements to be coated and configured to convey said elements from the entrance (105) to the exit (106) along a straight pathway, and, a suction system. The opposing sides of the channel are symmetrical about the pathway. Sets of spray guns (103a, 104a, 103b, 104b) for spraying coating powder at the elements are positioned symmetrically either side of the straight pathway. The suction system comprises vertical suction inlets (109a, 109b) mounted opposite one another on each opposing vertical side of the passage, the suction system being configured to provide equal amounts of suction through each of the opposing vertical suction inlets (109a, 109b).

A coating booth (101) for elements to be coated. The coating booth (101) comprises a passage between opposing vertical sides (107a, 107b, 108a, 108b) through which elements to be coated are conveyed. There is an entrance (105) at one end of the passage and an exit (106) at the other end of the passage. The coating booth (101) comprises a conveyor line (102) for supporting said elements to be coated and configured to convey said elements from the entrance (105) to the exit (106) along a straight pathway, and, a suction system. The opposing sides of the channel are symmetrical about the pathway. Sets of spray guns (103a, 104a, 103b, 104b) for spraying coating powder at the elements are positioned symmetrically either side of the straight pathway. The suction system comprises vertical suction inlets (109a, 109b) mounted opposite one another on each opposing vertical side of the passage, the suction system being configured to provide equal amounts of suction through each of the opposing vertical suction inlets (109a, 109b).

A powder feeding device includes: a hopper including a discharge port for discharging powder; and a conveyance device configured to move a conveyance surface disposed below the discharge port in a first direction and invert the conveyance surface in a front end portion. The hopper includes a front wall portion positioned on a downstream side of the discharge port in the first direction. A predetermined gap is formed between a lower end of the front wall portion and the conveyance surface. In the powder feeding device, powder deposited on the conveyance surface is conveyed in the first direction by the conveyance device with a thickness corresponding to the gap and dropped from the front end portion.

An apparatus for spreading particulate material has a bin for holding particulate material, a rotatable disc for broadcasting the particulate material to a ground surface, a conveyor for conveying the particulate material in a particulate material path from the hopper to the rotatable disc, and a plurality of sluices situated in the particulate material path between the bin and the rotatable disc. Each sluice receives a portion of the particulate material and delivers the portion of particulate material to a radial and/or angular position on the rotatable disc. At least one of the sluices is independently moveable to adjust the radial and/or angular position on the rotatable disc to which the portion of particulate material from the at least one independently moveable sluice is delivered.

An apparatus for spreading particulate material has a bin for holding particulate material, a rotatable disc for broadcasting the particulate material to a ground surface, a conveyor for conveying the particulate material in a particulate material path from the hopper to the rotatable disc, and a plurality of sluices situated in the particulate material path between the bin and the rotatable disc. Each sluice receives a portion of the particulate material and delivers the portion of particulate material to a radial and/or angular position on the rotatable disc. At least one of the sluices is independently moveable to adjust the radial and/or angular position on the rotatable disc to which the portion of particulate material from the at least one independently moveable sluice is delivered.

An in-line coating machine adapted to coat food products with a particulate coating material has a food products conveyor; a coating device; an excess coating material separation station; an excess coating material recovery conveyor; and a particulate coating material elevator device. An elevator device fill assembly along the recovery conveyor is configured to fill the elevator device with recovered excess coating material. An adjustable discharge opening device controls a discharge opening in the recovered excess coating material bed support. An adjustable upper layer diverter device engages an upper layer of the recovered excess coating material bed passing over the recovered excess coating material bed support and diverts at least a portion of the upper layer at an adjustable rate into the particulate coating material elevator device.

A high speed granule delivery system and method is disclosed for dispensing granules in intermittent patterns onto a moving asphalt coated strip in the manufacture of roofing shingles. The system includes a granule hopper and a rotationally indexable pocket wheel in the bottom of the hopper. A series of pockets are formed in the circumference of the wheel and the pockets are separated by raised lands. A seal on the bottom of the hopper seals against the raised lands as the wheel is indexed. In use, the pockets of the pocket wheel drive through and are filled with granules in the bottom of the hopper. As each pocket is indexed beyond the seal, it is exposed to the moving asphalt coated strip below and its granules fall onto the strip to be embedded in the hot tacky asphalt. The speed at which the wheel is indexed is coordinated with the speed of the asphalt coated strip so that granules and strip are moving at about the same forward speed or at a preselected ratio of speeds when the granules fall onto the strip. Well defined patterns of granules are possible at high production rates.

A high speed granule delivery system and method is disclosed for dispensing granules in intermittent patterns onto a moving asphalt coated strip in the manufacture of roofing shingles. The system includes a granule hopper and a rotationally indexable pocket wheel in the bottom of the hopper. A series of pockets are formed in the circumference of the wheel and the pockets are separated by raised lands. A seal on the bottom of the hopper seals against the raised lands as the wheel is indexed. In use, the pockets of the pocket wheel drive through and are filled with granules in the bottom of the hopper. As each pocket is indexed beyond the seal, it is exposed to the moving asphalt coated strip below and its granules fall onto the strip to be embedded in the hot tacky asphalt. The speed at which the wheel is indexed is coordinated with the speed of the asphalt coated strip so that granules and strip are moving at about the same forward speed or at a preselected ratio of speeds when the granules fall onto the strip. Well defined patterns of granules are possible at high production rates.