Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1999-06-17
2002-03-05
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06352324
ABSTRACT:
DESCRIPTION
1. Technical Field
The present invention relates to an ink circuit, as well as to an ink jet machine and a conditioning machine or a conveyor using such a circuit.
2. Prior Art
A prior art device is described in U.S. Pat. No. 4,862,192. This device is an ink jet point printer, with an ink circuit incorporating a device for the transfer of thick ink from a first supply tank and, independently thereof, additives from a second supply tank, into an ink chamber. Ink from said ink chamber is supplied under pressure to a writing head. Ink is returned to the ink chamber through a recovery channel, traversing the writing head and recovering the ink droplets which have not been deflected for writing purposes. The transfer device uses pressurized air for transporting the ink between an ink tank connected to the writing head, a mixture tank connected to the supply tanks, and a recovery tank connected to the recovery channel. The mixture or mixing tank can be alternatively connected to a suction line or to a delivery line.
This device suffers from numerous disadvantages. It requires the use of an air pressure regulator, which must be precise, fast, have no hysteresis so as not to modify the printer operating conditions, have a passage diameter of considerable size at the outlet so as not to lead to an overpressure during ink transfers accompanying a high pump capacity. It does not permit an ink jet droplet speed regulation. It has a manual, precision pressure regulator. It has two other air pressure regulators, which increases to three the number of regulators used. It uses a transfer pump (volume) with a considerable displacement of a unidirectional nature. This non-reversible pump does not make it possible to implement rapidly all the cycles necessary for a printer rinsing or emptying or an ink colour change. It uses a main filter downstream of the accumulator or storage tank, which requires a permanent adjustment of the operating pressure in order to compensate a clogging thereof. Additive addition is a function of the operating conditions and requires a manual setting. The electrical/hydraulic separation is brought about by using solenoid valves, which control pneumatically controlled valves. This relaying principle increases the number of components (cost and reliability aspects). It has components integrated in the interior of a machined unit. It has no temperature sensor. Therefore temperature variations can be interpreted as ink quality variations.
The invention is therefore directed at an ink circuit making it possible to obviate these various disadvantages.
DESCRIPTION OF THE INVENTION
The present invention describes an ink circuit more particularly comprising an ink cartridge, an additive cartridge, a recovery tank, an accumulator or storage tank, a main filter, solenoid valves, an ink transfer pump equipped with a pressure and temperature sensor, which provides information on the operational hydraulic and thermal conditions and an air pressure regulator, said ink circuit being characterized in that it comprises a double face support unit having a hydropneumatic face and an electronic face making it possible to separate the hydraulic, pneumatic and electronic assemblies, all the functional components being fitted outside one or other of the two faces.
Advantageously, the relative arrangement of certain components contributes to an improvement in the overall functionality of the ink circuit. Thus, the air/ink separation is ensured by an arrangement of the air-operating components in the upper part of the circuit and the mainly ink-operating components in the lower part thereof (natural separation by gravity). The pump is also located below the recovery tank and the storage tank, so as to naturally ensure a purging of said pump.
In the storage tank, a first liquid-pressure regulation is assured by the pump, whilst a second air-regulation is assured by means of two solenoid valves, one being located between the storage tank and one or more head pressurizations through gauged orifices and the other between the gauged orifice or orifices and the pressure regulator.
The first solenoid valve makes it possible to inflate or deflate the storage tank independently of the pump.
The second solenoid valve makes it possible to control the head pressurization, said option being directly controlled by the software in order to have a permanent pressurization of the head, said solenoid valve being in the open position (permanent electrical control) and for eliminating pressurization, the control of said solenoid valve being deactivated.
A third solenoid valve makes it possible to control the supply of a venturi tube (vacuum generation). This solenoid valve more particularly makes it possible to stop the vacuum on stopping the ink jet or jets. This in particular prevents any ink quality drift (needless evaporation), which occurs on stopping the ink jet on circuits not having the possibility of stopping vacuum generation.
Advantageously, the pressure sensor, which can be located in the pump, makes it possible to control the driving pressure of the pump. The driving pressure control cycle is controlled by solenoid valves.
The pressure read by the pressure/temperature sensor is then very close to the pressure prevailing in the chamber. This pressure is also very close to the pressure prevailing at the pressure regulator outlet. This sensor then has a pressurestat function and is then used for controlling the presence of the air system or network.
The pressure and temperature sensor makes it possible, during the phase of setting the operating parameters of the machine, to obtain information on the set pressure at the regulator outlet and on the vacuum in the recovery tank. On other prior art circuits, these informations are given by a needle pressure gauge (solely for indicating the regulated or set pressure) and a needle vacuum gauge (solely for indicating the operating vacuum). This sensor makes it possible to avoid the multiplicity of components and gives a more precise and simpler information (the pressure level being read directly on the screen or display of the machine) than needle indicators or gauges. This information can be directly used by software.
Advantageously, the hydraulic and pneumatic links within the circuit take place without using pipes or tubes and without any connection, being directly integrated by moulding into the unit in the form of channels. The hydraulic links with the head are implemented by fast, self-sealing couplings. The air filters are fitted to the unit by a fast fixing system (screwing or bayonet). No pipe is connected to said filters, so that the replacement of these components becomes a simple, clean operation requiring no tool (possibility of manual fitting and dismantling).
Moreover, the accessibility of the ink and additive cartridges and the main filter associated with the use of the reversible pump ensures a rapid colour change.
Advantageously, the ink circuit comprises a double pressure regulation accumulator (by air or liquid). The first regulation functions in liquid by means of the pump and corresponds to the ink supply of the jet, whilst the second regulation functions in air.
This regulation in air in particular makes it possible to relay the liquid regulation when the tanks containing the ink are empty. Thus, use is made of all the ink contained in the machine (including that of the storage tank) prior to the declaration of a blocking fault for the machine. It also ensures the maintaining of a stable pressure in said storage tank throughout the cycle of placing the cartridges under atmospheric pressure. It also ensures the supply of the air pocket of the storage tank without passing via the pump. It also permits a very rapid variation over the entire extent (extending from the vacuum generated by the venturi tube up to the outlet pressure of the regulator) of the pressure prevailing in said storage tank, said rapid and controlled variations of the pressure in the storage tank being used for the stopping and starting cycles of the jet or j
Pagnon Alain
Souvignet André
Barlow John
Imaje S.A.
Pearne & Gordon LLP
Stewart Jr. Charles W.
LandOfFree
Ink jet printing device and circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet printing device and circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet printing device and circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2830149