Method and apparatus for dispensing material in a printer

A printer for printing a viscous material at predetermined positions forming a pattern on a substrate, the printer comprising:

• a frame;
• a device, mounted to the frame, having a number of perforations arranged to form the pattern;
• a support apparatus, coupled to the frame, that supports the substrate in printing
• position beneath the device;
• a material dispenser having a chamber to contain the viscous material to be printed on the substrate, the chamber having an opening through which the viscous material is dispensed, the material dispenser being coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate, the material dispenser further having at least one port and a removable cartridge coupled to the port, the removable cartridge containing material to be dispensed and having an inlet to receive pressurized air to force material from the cartridge through the port and out of the opening of the chamber;
• and
• a device to prevent leakage of the viscous material from the chamber after the material dispenser is lifted from the substrate.

A method of controlling temperature of a viscous material to be printed by a material dispenser of a printer at predetermined positions on a substrate forming a pattern, the material dispenser being constructed and arranged to print the viscous material on the substrate and having a chamber in which the viscous material is contained with an inlet to receive the viscous material and an opening through which the viscous material is dispensed to the substrate, the method comprising the steps of:

• measuring a temperature of the viscous material contained in the chamber of the material dispenser;
• detecting a differential between a value of the measured temperature and a value of a desired temperature;
• and
• adjusting the temperature of the viscous material by applying a sufficient amount of heat to a conduction rod disposed within the chamber to maintain the desired temperature;
• and
• reducing the temperature of the viscous material to maintain the desired temperature by removing a sufficient amount of heat from the conduction rod by forced convection.

A printer for printing a viscous material at predetermined positions forming a pattern on a substrate, the printer comprising:

• a frame;
• a device, mounted to the frame, having a number of perforations arranged to form the pattern;
• a support apparatus, coupled to the frame, that supports the substrate in printing
• position beneath the device;
• a material dispenser having a chamber to contain the viscous material to be printed on the substrate, the chamber having an opening through which the viscous material is dispensed, the material dispenser being coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate, the material dispenser having a retraction device that prevents leakage of the viscous material from the opening after dispensing is complete;
• and
• a temperature control system to control the temperature of the viscous material contained in the chamber, the temperature control system including a temperature sensor disposed on the material dispenser to measure temperature of the viscous material contained in the chamber, and a controller coupled to the temperature sensor to control a temperature of a heating and cooling element disposed in the chamber to maintain the temperature of the viscous material at a desired value, wherein the heating and cooling element includes a conduction rod disposed in the chamber having a first terminal end and a second terminal end and of a length sufficient to control temperature of the viscous material contained within the chamber.

A printer for printing a viscous material at predetermined positions forming a pattern on a substrate, the printer comprising:

• a frame;
• a device, mounted to the frame, having a number of perforations arranged to form the pattern;
• a support apparatus, coupled to the frame, that supports the substrate in printing
• position beneath the device;
• a material dispenser having a chamber to contain the viscous material to be printed on the substrate, the chamber having an opening through which the viscous material is dispensed, the material dispenser being coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate, the material dispenser having a retraction device that prevents leakage of the viscous material from the opening after dispensing is complete, the material dispenser further having at least one port and a removable cartridge coupled to the port, the removable cartridge containing material to be dispensed and having an inlet to receive pressurized air to force material from the cartridge through the port and out of the opening of the chamber;
• and
• a pressure control system to control on a real-time basis the pressurized air delivered to the cartridge to maintain the pressure with which the viscous material is forced from the cartridge and to maintain the pressure in the chamber at a desired value during dispensing.