Thermal jet printhead

 

The invention relates to the technique of inkjet printing and can be used in inkjet printers and other printing devices. The use of the invention provides a marginal increase in the frequency of generation of droplets of the injected fluid and improving operational performance printing devices. To do this, the print head includes a bearing dielectric or conductive sequential basis it thermoseparation, resistive and switching layers, dielectric and thermoprotei layers, which formed the working microvolumes with the system inlet channels and hydraulic resistances, thermoprotei the layer system of the inlet channels, the hydraulic resistances and working microvolumes overlapped flexible multilayer membrane. Working microvolumes filled with working liquid, and above the flexible multilayer membrane is jet plate, ink channel, and the microvolumes are filled with the injected fluid. This design and combination of materials in head design provides increased heat transfer and accelerates the cooling of the working fluid, thereby increasing performance. 5 C.p. f-crystals, 4 Il.

Known design thermal jet printhead containing a dielectric substrate on which are formed sequentially thermotherapy, resistive and switching layers that make up the managed system resistive heating elements and nozzle plate with amounts made them spellname holes and filled with the injected fluid (SU 2051042, 41 J 2/05, 1995).

A disadvantage of the known technical solution is limited scope - low efficiency of use of similar design when using the injected liquid containing the pigment. In addition, the injected fluid interacting with the device with a heating resistive element, leads to premature release of the latest of the system and reduces the resource of a thermal jet printhead as a whole.

The closest in technical essence and the achieved effect is a technical solution thermal jet printhead containing a dielectric base, resistive and switching layers, forming operated from the outside of the heating resistive elements, a flexible membrane located above the heating resistive element is Anna design printhead flexible membrane, made of silicone rubber, is located between the plate with the ink chamber and barriers, forming pockets, interconnected z-shaped channels, and at the bottom of the pocket are resistors. In the pocket between the membrane and the resistor is the working fluid, which upon heating resistor creates vapor bubbles, breaking that create a more striking effect on the membrane with the subsequent ejection of ink droplets from the ink chamber. The main advantage of this technical solution is that it eliminates direct contact of the ink with the heating resistive elements.

However, the disadvantages of this technical solution is: - insufficient frequency of operation of the device due to poor heat transfer working fluid in the formation of bubbles and the delay time of condensation; - uncontrollable wetting the surface of the plate to allow the injected fluid, which reduces the efficiency of injection of ink; - low efficiency of the device due to the hydrodynamic shock in the process of breaking bubbles of steam and outflow of the working fluid through the channel system when the local heating resistive element; all pockets of the printhead about the con when one of the resistors in the other pockets, what causes false positives nozzles - provokes the release of additional drops; the membrane of silicone rubber does not ensure the integrity of the working chamber when the boiling liquid and has no dynamic elasticity for quick ejection of the ink, resulting in lower limits of the oscillation frequency drops, and in General, to reduce operational characteristics of device operation and print quality.

The present invention aims at solving the technical problems associated with the elimination of the above disadvantages.

Achievable technical result is to improve the operational characteristics of thermal jet print heads, namely, increasing as the frequency characteristics of the printhead, and the reliability of their work, by improving the parameters of tightness.

To implement the above objectives of the present invention is designed thermal jet printhead containing a dielectric substrate with successively formed therein resistive and switching layers, a flexible membrane microvolumes and a system of channels formed by the structure thermoproteus and the dielectric layer and the flexible membrane filled with the working of the LM is as thermoproteus layer, it is preferable to use the metal type aluminum, copper, chromium and polysilicon or the structure of chrome-copper-chrome total thickness of not less than 1/2 of the thickness of the working fluid. This combination of materials on the barriers leads to an increase in heat transfer and accelerates the cooling of the working fluid; - resistive layer is formed of polysilicon with different sizes of blocks in the volume of the layer with high surface roughness; - closed system of the inlet channels and the microvolumes over the resistors sealed, and the canal system provides flow rates formed in the volume between the dielectric layer and a flexible membrane or thermoprotei layer and the flexible membrane; the flow rates are between microvolumes and lead channels, and their value is selected from the following interval
where- coefficient depending on the viscosity of the working fluid and the averaged values of the wettability of the walls of the resistor; l is the length of flow rates; hb4 is a cross - section of flow rates (μm2), K - coefficient depending on the cross section of flow rates and mode of operation thermal jet printhead, with all values except coefficientkey thermal jet printhead (masks and so on);
- working fluid is thermally, chemically and electrochemically stable and wets the surface of microvolumes and canals;
- the inner surface to allow the plate has an additional layer, well-wettable injected fluid, and the outer surface to allow the plate has a layer that is not wettable injected fluid;
- jet plate contains a distribution chamber with the injected fluid and the channel system; jet plate is manufactured, for example, by electroforming, where at the same time in one operation made holes specified value, the volume of ink which is connected by canal with the ink distribution chamber;
- flexible membrane is made in the form of multilayer formation of polymer - metal and polymer - inorganic dielectric.

In Fig.1 shows a cross-section design thermal jet printhead containing a carrier dielectric or a conductive base material with good thermal conductivity (1) with successively deposited on it thermoseparation (2), resistive (3) and switching (4) layers forming the heating elements, then deposited dielectric (5) and thermoprotei (6) layers, which are formed of RA is Dvadasi channels, flow rates and microvolumes overlain by a flexible membrane (9), work microvolume (7) filled with the working fluid (10), above the membrane (9) is located jet plate (11) containing ink microvolumes (12) filled with the injected liquid (ink) (13) flowing through the ink channels (14).

In Fig. 2 shows a variant of execution to allow the plate (11) is coated on its inner and outer surface of the additional layers on the inner surface formed by the inner layer (15), good wetting (contact angle (10-30o)) the injected fluid (13) and the outer - the outer layer (16) with poor wettability (wetting angle (70-90o)) the injected fluid.

In Fig. 3 an embodiment of a hermetically sealed system of the inlet channel (17) and working microvolumes (7) located above the resistive layer (3), and the system inlet channel (17) contains flow rates (8) formed in the volume between the dielectric layer (5) and a flexible membrane (9).

In Fig. 4 shows an example of performing multi-layer flexible membrane (9), consisting of a polymer (18), metal (19) and the adhesive (20) layers.

The proposed thermal jet printhead goal and the inlet channel (17) is the working fluid (10), which is thermally, chemically and electrochemically stable and wets the surface of the work microvolumes (7) of the inlet channel (17). The thickness of the layer of working fluid (10) is 3-10 μm. Ink microvolumes (12) to allow the plate (11), made for example of Nickel, filled with the injected fluid (13) - ink consisting of a mixture of coloring matter, of ethylene glycol and water, which wets well the inner surface (15) to allow the plate (11). Ink through an ink channel (14) receives the ink microvolume (12) to allow the plate (11).

Geometrical dimensions to allow the plates (11) are determined by the topology of the tooling during manufacture to allow the plate (11).

The external surface to allow the plate (16) is covered by a polymer layer thickness of ~1-3 µm, providing a contact angle of no more than ~30oand not less than 10o. The inner surface to allow the plate (15) is covered by a layer providing a contact angle of not less than ~70oand not more than 180ofor example, a tetrafluoroethylene. These layers allow the plate (11) ensure effective penetration of the injected fluid (13) in ink microvolumes (12) to allow the plate (11) and the subsequent ejection of the droplet phase injector is I have different sizes of blocks in the volume of the layer with a high surface roughness (0.1 to 0.15 microns).

To prevent deformation of the flexible membrane (9) adjacent microvolumes in the proposed design for thermal jet printhead is provided flow rates (8) providing damping of the shock waves of the working fluid (10). To improve the elastic properties and the tightness of the flexible membrane (9) is made of multilayer and comprises a polymer (18), metal (19) and the adhesive (20) layers. The proposed solution multilayer flexible membrane (9) provides layer-by-layer mutual elimination (healing) defects layers of the membrane in the process and thereby increases the term of her work. This multi-layer formation of the membrane (9) allows for increased tightness workers (7) and ink (12) microvolumes and the desired dynamic elasticity at the time of formation of steam in the working microvolume (7) required for transmission of the pulse pressure of the injected fluid (13). The thickness of the flexible membrane (9) is selected from 1 to 3 μm. Structurally, it has at least 3 layers. In the specific example of implementation, the first layer is a polyimide (18), the second metal (19), such as chromium or aluminum, and the third adhesive layer (20). A possible embodiment of a flexible membrane of two modifications of PI (10) after removing the electrical pulse with a resistive layer (3), is also formed thermoprotei layer (6) located between the dielectric layer (5) and a flexible membrane (9). Thermoprotei layer (6) may be formed from various metals, including multi-layered structure of chromium, copper, and chromium. In this structure, the chromium serves as the adhesion layer. The total thickness of the above example implementation thermoproteus layer (6) is (0,3-0,9) thickness of the working fluid (10) over the resistive layer (3).

As the working fluid (10) is selected materials, characterized by a number of parameters. The working fluid (10) should not decompose or change its chemical composition at temperatures up to 300-350oC. the working fluid should not dissociate when applying a supply voltage to ~21 Century, the Resistance of the working fluid should not be less than ~108Ohms at temperatures from normal to ~ 350oC. the working fluid should boil at temperatures of 100-150oWith at normal pressure environment and have a high vapor pressure at t = 250-350oC. To avoid diffusion through a flexible membrane (9), as the working fluid (10) it is preferable to use high-molecular compound with the structure, bleet boiling point in the range of 90-110oWith a high vapor pressure, and the other with a higher boiling point and high thermal conductivity. Based on these requirements, as the working fluid (10) may be selected from xylene, toluene, heptane, and other high-molecular liquid.

Thermal jet printhead works as follows.

When applying an electric pulse to one of the resistive layer (3) through a connecting layer (4) is immediate (within microseconds) formation of vapor of working fluid (10) to the stepwise increase in the pressure in the working microvolume (7). A flexible membrane (9) is deformed and pushes from the ink microvolume (12) to allow the plate (11) drop the injected fluid (13). After electric pulse results in condensation of the bubble fluid (10) and a flexible membrane (9) is returned to its original position. After steam condensation and leakage of the injected fluid (13) in ink microvolume (12) above the flexible membrane (9) cycle supply electrical pulse can be repeated.

As an example, consider the options of specific performance thermal jet printhead.

Thermal jet print heads were performed on podloga polysilicon thickness (0,55-0,65) microns, the value of the resistors was maintained in the range (25-35) Ohm (including the transition resistance). As a switching layer used aluminum of a thickness of 0.8 to 1.5 microns). The dielectric layer was made from heat-resistant polyimide thickness not less than 0.5 μm and not more than 2.5 μm, thermoprotei layer - based structure of chrome-copper-chrome. A flexible membrane is made of a multilayer - adhesive layer of the adhesive polyimide, a barrier layer of chromium and a layer of polyimide coated with chromium on the periphery of microvolumes. The total thickness of the flexible membrane was ~(2,5-3) μm. The nozzle plate made from Nickel-cobalt coated inner surface of a polyimide, and the outer gold.

The thickness of the coating to allow the plate is not more than ~1 μm and not less than 0.1 μm.

As the working fluid used xylene as the injected fluid is a mixture of distilled water, ethylene glycol and dye.

Implemented design thermal jet printhead has provided the following specifications:
- dimensions of the chip 76005300 μm;
- diameter supernova holes 50 microns;
- the distance between spellname holes 169 microns;
- the minimum size of the element design, the pads 240 microns;
- dimensions of the active part of the resistive layer 9090 microns;
- the number of nozzles on a single chip 50;
- resolution of 300 dpi.


Claims

1. Thermal jet printhead containing a carrier dielectric or conductive sequential basis it thermoseparation, resistive and switching layers, dielectric and thermoprotei layers, which formed the working microvolumes with the system inlet channels and hydraulic resistances, thermoprotei the layer system of the inlet channels, the hydraulic resistances and working microvolumes overlain by a flexible membrane, working microvolumes filled with working liquid, and above the flexible membrane is located jet plate, ink channel, and the microvolumes are filled with the injected fluid.

2. Thermal jet printhead under item 1, characterized in that the working microvolumes with the system inlet channels and hydraulic resistances made of metals with high thermal conductivity and polymers.

3. Thermal jet printhead under item 1, characterized in that as thermoproteus layer using a single layer or a multilayer structure of the metal is beraut from the following relationship:

where- coefficient depending on the viscosity of the working fluid and the wettability of the resistive layer; and

l is the length of flow rates;

hb4 a cross-section of flow rates, μm2;

k - coefficient depending on the cross section of flow rates.

5. Thermal jet printhead under item 1, characterized in that the inner surface to allow the plate includes the additional layer for the contact angle of the injected liquid is not more than ~30and not less than 10and the outer surface to allow plate - layer contact angle of the injected liquid is not less than ~70and not more than 180.

6. Thermal jet printhead under item 1, characterized in that the flexible membrane is made in the form of multilayer formation of polymer - metal and polymer - inorganic dielectric.

 

Same patents:

Microinjector // 2146621

The invention relates to an injector device and method for the discharge of liquid from microinjector

The invention relates to inkjet printing heads and contains many parallel channels, each separated from the adjacent channel side walls, able to move in the transverse direction in response to the control signal

The invention relates to means of communication and recording information on paper or other media and can be used in a thermal jet printing devices

The invention relates to devices for displaying information on a paper medium

FIELD: ink jet printers.

SUBSTANCE: method includes precipitating resistive layer and conductive layer on insulated substrate, forming a resistive heating element, forming of insulating barrier layer above contour of said conductive layer, forming of gap in said barrier layer, forming of metallic layer being in electrical contact with said conductive layer contour through said gap, having geometry, which opens predetermined portion of said contour of conductive layer, making a layout from metallic layer from said contour of conductive layer through said gap in insulating barrier layer to adjacent portion of said insulated substrate, so that layout from metallic layer on said adjacent portion of said insulating substrate forms a relatively large and flat area, remote from said conductive layer contour, for forming displaced spring contact. After precipitation of resistive layer and conductive layer on insulating substrate, contour of conductive layer is formed first, having a recess, forming later said resistive heating element, and then contour of resistive layer is formed with overlapping of conductive layer contour for value, exceeding precision of combination during lithography process and error of dimensions during etching of resistive layer.

EFFECT: higher quality, higher reliability, higher efficiency.

2 cl, 10 dwg

FIELD: printers.

SUBSTANCE: printer has ink cartridge, carriage where ink cartridge is installed, and printing head mounted onto carriage. Ink cartridge has case for placing ink, ink supplying department where hole for feeding ink is formed, memory unit for storing data on ink in case, contact outputs unit disposed onto second side wall of case and connected with memory unit. Hole for supplying ink is disposed onto first side wall of case. Cartridge has fitting element protruding from second side wall of case for correct installation of ink cartridge relatively printer at the moment when ink cartridge is placed into printer. Precise connection of ink's output unit and printer's output unit is provided. Higher degree of freedom is provided at installation of ink cartridge's contact output unit.

EFFECT: improved efficiency of operation.

28 cl, 16 dwg

FIELD: jet printing, in particular, narrow-film jet printing head having control circuits on field transistors configured so as to compensate for the parasitic resistance of supply routes.

SUBSTANCE: the narrow jet printing head (100A) has effective control circuits on field transistors, which are configured so as to compensate for the parasitic resistances of the supply routes (86a, 86b, 86c, 86d). In addition, the jet printing head has ground buses, which overlap the active areas of the control circuits on field resistors.

EFFECT: provided compactness of the head at a large number of drop formers.

21 cl, 15 dwg

FIELD: jet printers.

SUBSTANCE: device has to be jet-printing head. Printing head has many drop generators reacting to excitation current and address signals; printing head is used for releasing ink. Jets printing head has first and second drop generators disposed in printing head. Any drop generator is made for reception excitation current from excitation current source. Any drop generator is made for reception of address signals from common address source. Jet printing head also has switching unit connected between common address source and any drop generator. Switching device is made for reaction to resolution signals for selective application of address signal for either first or second drop generator.

EFFECT: high speed of printing.

21 cl, 11 dwg

FIELD: engineering of jet printing devices.

SUBSTANCE: device contains jet printing head, having a set of electric contacts: address contacts and resolution contacts for unblocking drop generators 42, and excitation currents contacts for feeding excitation currents for enabling drop generators for selective discharge of ink from them. Generated in printing device are periodic signals of address (A(1-13)) and signals of resolution (E(1-2)) for contacts of address and resolution on printing head. Also, fed selectively from printing device are excitation currents (P(1-16)) to perform generation of images on print carrier. Each individual heating element 44 is controlled by excitation circuit, containing three field transistors 48,50,52. Under effect of first and second signals, E(1) and E(2), and address signal A(1), switching device 48 selectively switches on for letting current through heating element 44, in case if excitation current is received from excitation source P(1).

EFFECT: decreased number of contacts between printing head and printing device, high quality of printing due to provision of possible positioning of large amount of drop generators in printing heads.

4 cl, 11 dwg

FIELD: engineering of stream printing devices containing printing head assembly, receiving signals for activating drop generators for selective discharge of ink.

SUBSTANCE: device for controlling operation of drop generators is made so, that only one of them is enabled at one time moment. Device for controlling operation of drop generators is made with possible generation of signal of address and first resolution signal before excitation current for first drop generator and second resolution signal before excitation current for second drop generator.

EFFECT: prevented cross interferences on liquid during simultaneous discharge of drops from closely positioned drop generators.

2 cl, 11 dwg

FIELD: printing.

SUBSTANCE: invention relates to a substrate for jet printing head, printing head and jet printing device. The said substrate with electrical heat converters intended for generation of heat required for releasing the ink incorporates a logic circuit to generate a unit selection signal to select the said converters in separate units proceeding from the voltage amplitude first level input signal and the element excitation signal for excitation of every electrical heat converter in the selected unit at the second voltage amplitude level exceeding the first one, and the excitation circuit intended for every electrical heat converter to excite the said converters in separate units proceeding from the unit selection and element selection signals of the second level of voltage amplitude, the said signals coming from the logic circuit. The method of controlling the excitation of electrical heat converters incorporates feeding the voltage amplitude first level input signal allowing for the input signal, the unit selection signal to select the unit of electrical heat converters in separate units and the element excitation signal to excite every electrical heat converter in the selected unit at the second level of the voltage amplitude exceeding that of the first one, and exciting the electrical heat converters in separate units allowing for the unit selection and element selection signals of the second voltage amplitude level coming from the logic circuit, the above functions are realised by exciting the excitation circuit designed for every electrical heat converter. The jet printing head contains outlets for ink and the substrate supporting the electrical heat converters arranged in compliance with outlets. The jet printing head cartridge carries a jet printing head and a cup filled with ink to be fed into the printing head. The jet printing device has outlets to let out the ink and a substrate whereon installed are electrical heat converters arranged in compliance with outlets. The circuit design is developed wherein the logic excitation voltage is converted into the voltage of elements excitation without increase in the length of segments in direction perpendicular to the direction of the matrix of segments. Annual output of finished products is increased and circuitry is simplified by reducing the circuit of pulse-amplitude modulation and the number of elements on the substrate.

EFFECT: increased annual output and simplified circuitry.

12 cl, 12 dwg

FIELD: technological processes; printing industry.

SUBSTANCE: device for ejection of fluid medium contains multiple activating cells, activation bus bar arranged with the possibility of energy signal reception and generator of address intended for formation of address signals sequence. Address generator contains shift register, which has double-stage cells designed for reception of input signal and storage of input signal, and logical elements that are intended for reception of input signals during every address time slot and formation of address signals sequence. Energy signal represents pulse of energy during every address time slot in sequence of address time slots for excitation of selected permitted activating cells. Unit of printing head is suggested that contains controller for generation of set of signals, in preset configuration, the first bus bar for passage of the first pulses, the second bus bar for passage of the second pulses, the first group of resistors and the second group of resistors, which are connected with the possibility to conduct on the basis of mentioned set of signals and pu;se signals.

EFFECT: device provides specific height of printing strip and makes it possible to retain costs.

22 cl, 27 dwg

Up!