Abstract: The present invention is directed to a power converter that can be used to interface a motor 4 that requires variable voltage at variable frequency to a supply network (bus) providing a nominally fixed voltage and nominally fixed frequency. The power converter includes a first active rectifier/inverter 10 electrically connected to the stator of the motor 4 and a second active rectifier/inverter 14. Both the first and second active rectifier/inverters include a plurality of semiconductor power switching devices. A dc link 12 is connected between the first active rectifier/inverter and the second active rectifier/inverter. A filter 16 is connected between the second active rectifier/inverter and the supply network and includes network terminals. The power converter includes a first controller 18 for the first active rectifier/inverter and a second controller 20 for the second active rectifier/inverter.

Abstract: A method of controlling a plurality of power converters 1a, 1b and 1c can be used to interface to a supply network, ac busbar etc. Each power converter includes a network bridge 14 operating in accordance with a pulse width modulation (PWM) strategy having the same switching period and which causes at least one unwanted harmonic in the supply network voltage. The method includes the step of providing the switching period of the PWM strategy of each network bridge with a different time offset relative to a time datum such that the at least one unwanted harmonic in the supply network voltage is at least partially cancelled. Two alternative ways of providing the time offset are described.

Abstract: A molding tool is provided for forming solid ink sticks. The molding tool comprises a vessel having at least one sidewall defining a cavity for receiving molten phase change ink material. The molding tool includes a lid for covering an opening over the cavity of the vessel. The lid has an interior surface for at least partially enclosing the cavity. The enclosed cavity has a shape corresponding to at least a portion of an ink stick shape. The at least one sidewall of the vessel and/or the interior surface of the lid are configured to flex to facilitate release of an at least partially solidified ink stick from the cavity.

Abstract: An ink stick for use in a phase change ink imaging device comprises an ink stick body having a leading surface, a trailing surface, and a top surface. The top surface has a front edge that is rearwardly offset from a top edge of the leading surface, and a back edge that is at least partially rearwardly offset from the top of the trailing surface. A leading canted face extends between the top edge of the leading surface and the front edge of the top surface. A trailing canted face extends between the top edge of the trailing surface and the back edge of the top surface. The back edge includes a key that is complementary to an insertion opening key of an ink loader.

Abstract: A system for an ink delivery system comprises a feed path having an insertion end and a melt end, and an ink stick transport for moving at least one ink stick between the insertion end and the melt end of the feed path. At least one sensor is positioned along the feed path. A controller is configured to actuate the transport to move at least one ink stick in a first direction from the insertion end toward the melt end of the feed path so that a coded sensor feature of the at least one ink stick actuates the at least one sensor to generate a signal. The controller is configured to actuate the transport to move the at least one ink stick in one of the first direction and a second direction toward the insertion end of the feed path in response to the signal.

Abstract: Insertion elements can be used to provide keying features for ink loaders. Such elements connect to ink stick receptacles in the loader. The insertion elements can provide a border to a non-integer number of edges of the receptacles and be shaped to complement at least a portion of the perimeter of an ink stick. A solid ink loader that includes at least one feed channel for receiving ink sticks can use the insertion elements. The insertion elements can be part of a keying system that includes keying features supplied by both the insertion element and the receptacle itself. Multi-component key plate systems can be used as well.

Abstract: An ink stick cooperates with structure in a feed channel of a phase change ink printer to reduce steering effects from pushing the ink sticks along the longitudinal axis of the feed channel. The ink stick includes an ink stick body having a top surface, a bottom surface, a lateral dimension between two partial sides of the ink stick, and a lateral center of gravity within the lateral dimension, a support in a bottom surface of the ink stick body, the support being located at a position that is laterally offset from the lateral center of gravity within the lateral dimension, and a skew limiter in a side of the ink stick body that is opposite the lateral offset position of the support, the skew limiter being in the side of the ink stick body intermediate the bottom surface and the top surface of the ink stick body.

Abstract: An ink loader for a phase change ink imaging device comprises at least one guide member for maintaining alignment and orientation of ink sticks as the ink sticks feed to a melt area of an ink loader. The ink loader also includes a keyed opening through which ink sticks are inserted into the ink loader. The keyed opening is positioned with respect to the at least one guide member such that keying elements of ink sticks are spatially separated from the at least one guide member during and after insertion.

Abstract: A solid ink stick incorporates structural features and aspect ratios that facilitate movement of the ink stick through a feed channel. The ink stick includes an ink stick body having a width, a length, and a height, a first skew limiter in a lateral side of the ink stick, the first skew limiter having a length substantially equal to the length of the ink stick and a width that is less than one-half of the width of the ink stick, and a second skew limiter in a lateral side of the ink stick opposite the lateral side in which the first skew limiter is located, the second skew limiter having a length substantially equal to the length of the ink stick and a width that is less than one-half of the width of the ink stick.

Abstract: A plurality of ink sticks for use in phase change ink imaging devices comprises a first ink stick configured for insertion through an insertion opening of an ink loader for a first phase change ink imaging device and configured for insertion through an insertion opening of an ink loader for a second phase change ink imaging device. The plurality of ink sticks also comprises a second ink stick configured for insertion through the insertion opening of the ink loader for the second phase change ink imaging device and configured to be excluded from insertion through the insertion opening of the ink loader for the first phase change ink imaging device.

Abstract: The present invention provides a power converter that can be used to interface a generator that provides variable voltage at variable frequency to a supply network operating at nominally fixed voltage and nominally fixed frequency and including features that allow the power converter to remain connected to the supply network and retain control during supply network fault and transient conditions. The power converter includes a generator bridge electrically connected to the stator of the generator and a network bridge. A dc link is connected between the generator bridge and the network bridge. A filter having network terminals is connected between the network bridge and the supply network. A first controller is provided for controlling the operation of the semiconductor power switching devices of the generator bridge. Similarly, a second controller is provided for controlling the operation of the semiconductor power switching devices of the network bridge.

Abstract: A set of ink sticks includes multiple ink sticks, each adapted to be inserted in an insertion direction into one of the feed channels of a phase change ink jet printer. Each ink stick has a keyed surface substantially aligned with the insertion direction, and each of the keyed surfaces has a key feature having a position relative to the keyed surface that corresponds to the position of the feed channel relative to an aspect of the printer. A method of inserting an ink stick into the delivery system of a phase change ink jet printer includes orienting the ink stick with a keyed surface facing a particular direction and identifying the position of the key feature relative to the remainder of the keyed surface. An ink feed channel of the feed system having a coinciding position in the ink delivery system is identified, and the ink stick is inserted into the identified ink feed channel.

Abstract: An ink stick comprises a solid ink stick body adapted for insertion in an insertion direction into an ink loader of a phase change ink device. The solid ink stick body includes a top and bottom surface that are oriented substantially perpendicular to the insertion direction and a plurality of side surfaces that are substantially parallel to the insertion direction. The plurality of side surfaces define a plurality of corner edges that extend from the top surface to the bottom surface where adjacent side surfaces meet. A corner guide element extends at least partially along at least one corner edge in a feed direction of the feed channel. The corner guide elements are configured to engage guide members in the feed channel to restrain movement of the ink stick body in at least one direction other than the feed direction. The insertion direction is parallel to the feed direction.