Abstract: A liquid discharge head includes recording liquid flow paths communicated with plural discharge ports, a flow path formation member, upstream of the recording liquid flow paths, on which a recording liquid supply passage is provided, a recording liquid storing member, upstream of the recording liquid supply passage, in which a common liquid chamber is provided, a plug member for supplying recording liquid from the outside into the common liquid chamber, and a porous member at the end portion of the flow path formation member to remove dust particles and the like in recording liquid supplied from the common liquid chamber to the recording liquid supply passage. The porous member is arranged above a bottom face of the common liquid chamber.

Abstract: An ink jet print head assembly (10) includes at least one elongate ink jet print head chip (20) that is the product of an integrated circuit fabrication technique. The assembly (10) also includes at least one corresponding ink jet print head chip carrier (14) that defines an elongate recess (18) having a pair of opposed side walls (28). The, or each, print head chip (20) is received in one respective recess (18). The, or each, ink jet print head chip (20) and said respective recess (18) are dimensioned so that a gap (26) is defined between the, or each, ink jet print head chip (20) and each side wall (28). Resiliently deformable material (22) is positioned in each gap to retain the, or each, print head chip (20) in position in said respective recess (18).

Abstract: An ink jet recording head cartridge has a liquid container for retaining a liquid, a discharge circuit section which comprises a supply port for receiving the liquid in the liquid container, a nozzle in communication with the supply port, and a discharge energy generating element, provided in the nozzle, for discharging the liquid; and a flow path for leading the liquid from the liquid container to the discharge circuit section, wherein the flow path comprises a vertical portion extending from a portion connecting to the ink container, and a horizontal portion connecting to a lower end of the vertical portion and connecting to the supply port of the discharge circuit section, a throttle portion whose width becomes narrower in a supply direction of the liquid is formed in a portion, which connects to the vertical portion, of the horizontal portion of the flow path, and a groove shaped flow path whose width is narrower than the total width of the flow path is contiguously formed on an inner wall of the flow pat

Abstract: An ink container shell for an ink jet cartridge has spaced apart side walls, a front wall, a rear wall, and a bottom wall, and is provided with a partition structure which divides the interior thereof into three ink chambers, at least one of which has a non-rectangular profile in cross-section transverse to said side, front and rear walls. The partition structures enable varying the volumes of the ink chambers with respect to a given shell exterior profile and enable isolating two the chambers from one another by interposing the third chamber therebetween.

Abstract: A print engine assembly includes a support for a micro-electromechanical pagewidth print head. A single motor is controlled to dispense print media from a cartridge that is fast with the print head support and, at the same time, drive an air pump to direct air across the print head in order to keep it clear of debris. An air filter is provided to filter the air prior to it entering the air pump. The air is distributed to the print head support through a conduit that is formed in a molding which is shaped to receive the air pump.

Abstract: An inkjet cartridge. The inkjet cartridge includes a body and a seal member. The body includes a first chamber, a second chamber, a third chamber, a first exit, a second exit, a third exit, an opening, and a channel. Ink is received in the first chamber, the second chamber, and the third chamber. The second and third chambers communicate with the second and third exits so that the ink in the second and third chambers flows directly to the second and third exits. The channel communicates the first chamber and the first exit so that the ink in the first chamber flows to the first exit via the channel. The seal member is disposed on the channel via the opening, and seals the channel to prevent ink in the first chamber flowing through the first exit from flowing out of the opening.

Abstract: A liquid discharge head cartridge can assuredly supply a liquid discharge head with a liquid even when a bubble is generated within a liquid channel, and maintain excellent recording characteristics even in a configuration in which light recovery or no recovery is adopted. The cartridge includes a slit-shaped opening provided at an ink channel facing an ink-jet recording head, a filter provided at an ink introducing unit so as to contact an ink absorber, and ribs for supporting the filter that extend from an inner wall of the ink introducing unit to a substantially central portion of the filter.

Abstract: A inkjet printer cartridge is described including at least one print head for printing data on a support, wherein a thin printed circuit is permanently fixed to the printer cartridge and a miniature data processing unit fixed to the printed circuit analyzes a stream of printing commands for controlling the print head to authenticate the data to be printed on the support.

Abstract: The present invention provides a storing structure for storing an ink jet head including a nozzle communicated with an opening for discharging liquid, a liquid storing portion for storing the liquid to be supplied to the nozzle and a liquid introduction portion for introducing the liquid into the liquid storing portion from exterior, wherein, in the ink jet head, air is housed in the liquid storing portion and the liquid is contained at least in the nozzle, and a cap unit including an elastic cap for covering an area of the opening and a liquid absorbing member disposed in the elastic cap is closely contacted with and attached, around the opening, to a face in which the opening is formed, and the liquid introduction portion is communicated with atmosphere at least when inner pressure of the liquid storing portion is increased, thereby maintaining a space within the cap unit to a wetting condition.

Abstract: An ink flow control device for a printer having at least one print head includes a main body, an ink flow passage formed at least in part in the main body and constructed and arranged to communicate a supply of ink with a print head, a diaphragm carried by the main body and defining at least part of a pressure receiving chamber on one side of the diaphragm that forms part of the ink flow passage and a reference chamber on the other side of the diaphragm, a valve operably connected to the diaphragm and being moved by the diaphragm to control ink flow through the ink flow passage.

Abstract: A print cartridge includes a printhead and a plurality of distinct achromatic inks contained within a plurality of chambers in communication with the printhead.

Abstract: Apparatus include an inkjet pen with a body that defines a first ink reservoir configured to contain a first ink, and a second ink reservoir configured to contain a second ink. A print head is also included, and is operatively supported by the body, wherein the first ink reservoir and the second ink reservoir are each selectively connectible in fluidic communication with the print head. Methods of providing ink for an imaging process include providing an inkjet pen with a first ink reservoir and a second ink reservoir. A first ink with a relatively high color saturation of a given color is placed into the first ink reservoir. A second ink with a relatively low color saturation of the given color is placed into the second ink reservoir.

Abstract: An inkjet cartridge for use with a thermal inkjet printer includes a free ink chamber with a tube disposed therein, wherein the tube defines therein an entrained ink chamber. The tube can extend from the top of the free ink chamber to the bottom thereof. The tube is preferably laterally enveloped by the free ink chamber. The tube has an interior surface on which a longitudinal channel can be defined, and wherein the channel can be helical.

Abstract: A refillable fluid container system having a communication channel between the manifold and fluid reservoir that allows air to vent from the manifold to an air accumulation area with in the fluid resevoir.

Abstract: An ink absorbing substrate suitable for use in inkjet printing systems is provided. The substrate comprises at least one continuous fiber bonded to itself at points of contact to form a substantially self-sustaining structure for retaining ink. The continuous fiber preferably is a bicomponent fiber having a core material and a sheath material at least partially surrounding the core material. The core material preferably is a crystalline thermoplastic polymer and the sheath material preferably is low density polyethylene modified with a cycloolefin copolymer.

Abstract: An apparatus for recording and generating images includes a printing unit and an image recordal apparatus. The printing unit includes a carrier that is dimensioned to approximate a PCMCIA memory card. A media supply is receivable in the carrier. A page width print head assembly is mounted in the carrier to print images on the media. The page width print head assembly includes at least one print head chip and a suitable printing microprocessor that is configured to control operation of the print head chip. An ink supply mechanism is operatively arranged with respect to the print head assembly to supply the print head assembly with ink. A media feed mechanism is positioned in the carrier to feed media to and from the print head chip. Both the printing unit and the image recordal apparatus have complementary releasable data connectors so that the image sensing microprocessor can communicate image data to the printing microprocessor of the printing unit.

Abstract: An ink supply system for use with high speed multiple layer form collators includes a first ink supply reservoir in fluid communication with a second ink supply reservoir, and a pump to enable flow of ink from the first ink supply reservoir to the second ink supply reservoir. The second ink supply reservoir supplies ink to a print head. The second ink supply reservoir is divided into an inlet chamber into which ink from the first ink supply reservoir is received, an outlet chamber, the outlet chamber having a one or more outlets leading to print heads, and an overflow chamber. Internal partitions within the second ink supply reservoir ensure that the inlet chamber fills before overflowing into the outlet chamber and that the outlet chamber overflows into the overflow chamber. Ink settles in the inlet and outlet chambers thus allowing any turbulence to dissipate. A constant head pressure in the outlet chamber promotes constant ink flow and even print density.

Abstract: An ink cartridge includes an ink containing section including an ink absorbing body made of a porous material for retaining ink. The ink cartridge satisfies 200?N·R?320, where N is the cell density, expressed in the number of pores per inch, of the ink absorbing body before the ink absorbing body is contained in the ink containing section; and R is a compressibility, which is a volume ratio of the ink absorbing body when the ink absorbing body is contained in a compressed state in the ink containing section to the ink absorbing body before the ink absorbing body is contained in the ink containing section.

Abstract: The present invention provides an ink jet recording head in which a buffer chamber connected to a liquid supply path can be cleaned effectively. The ink jet recording head includes a recording head unit having a discharge portion for discharging ink, a tank holder unit to which an ink tank for containing the ink to be discharged at the recording head unit, and a liquid supply path formed between the tank holder unit and a flow path forming member joined to the tank holder unit in order to supply the ink contained in the ink tank to the recording head unit. A buffer chamber containing gas is connected to the liquid supply path and the buffer chamber is provided with an opening portion. The opening portion is closed by joining the recording head unit to the tank holder unit by joining the recording head unit to the flow path forming member.

Abstract: A liquid container has a movable member which defines a liquid containing space and which is displaced as the liquid is supplied, a valve for allowing a gas to be introduced into the containing space from the outside and for preventing the liquid from being extracted from the containing space to the outside, and an introduction channel for coupling the valve and the containing space to guide the introduced gas into the containing space. An intake port of the introduction channel located on the containing space side is positioned in an upper part of the containing space in an orientation in use. A negative pressure is kept substantially constant to consume the liquid completely. Since the air introduction for keeping the negative pressure at an adequate value is carried out in a region in a gaseous phase in the container, no leakage of ink occurs, and air is reliably introduced.

Abstract: In a system for laser welding work pieces along a collapsing weld interface, methods and apparatus include providing welding pads and/or stop projections on either or both of the work pieces to control the manner or amount of collapse. Preferably, the stop projections exist a separation distance from the weld interface while the welding pads exist at and form a portion of the weld interface. Buffers are taught between the weld interface and stop projection. The work pieces may comprise inkjet printhead lids and bodies. In another aspect, the invention teaches methods of laser welding inkjet printhead lids and bodies according to whether the inkjet printhead body embodies a mono or color ink body type and especially includes selective control of one or more laser light sources to illuminate the inkjet printhead lid in a specific pattern of light.

Abstract: An exemplary printing device and related systems are described. One exemplary printing device includes one or more print cartridges configured to selectively eject generally fluidic material onto a media. At least one print cartridge of the one or more print cartridges is configured to eject a first generally fluidic material comprising a slurried suspension.

Abstract: Cartridge total weight SN of an ink bag filled with ink is measured. Ink weight SU of ink stored in the ink bag is calculated from the found cartridge total weight SN (step S17). The ink weight SU is converted into a printable amount and this printable amount is stored in an IC chip as an initial value Sc for calculating a remaining amount (step S19). A printer reads the initial value Sc for calculating the remaining amount from the IC chip, subtracts the ink consumption amount from the initial value Sc for calculating the remaining amount to calculate a new ink remaining amount, and stores the calculated ink remaining amount in the IC chip.

Abstract: A printing cartridge including a body, the body having a base and a tower defining a passageway. The tower is made from a first polymer material, and has a proximal end and a distal end. The proximal end is attached to the base. The distal end includes a surface. A frame, made of a second polymer material different from the first polymer material, is attached to the surface of the tower. A filter is attached to the frame and positioned to extend over the passageway.

Abstract: An ink reservoir having a body and a cover disposed on the body is provided. A vent is disposed in the cover. The vent has a vent hole passing through the cover and an elongated vent path that communicatively couples the vent hole to an atmosphere surrounding an exterior of the ink reservoir. An oleophobically treated, porous membrane is disposed over the vent hole for acting to repel ink therefrom and for allowing airflow through the porous membrane and the vent.

Abstract: An ink jet cartridge includes an ink jet recording head; an ink container for containing ink to be supplied to the recording head; an ink supply source connecting portion which is provided in the ink container and which is connectable with an ink supply source to permit filling of the ink into the ink container; a pressure reduction source connecting portion connectable with a pressure reduction source for reducing pressure in the ink container to permit filling of the ink; an absorbing material provided in the ink container, the absorbing material is capable of retaining the ink and functioning as a negative pressure source for the recording head; a gas-liquid separating member which is disposed between the absorbing material and the pressure reduction source connecting portion and which has a gas permeability and liquid penetration resisting property; and supporting members, disposed at respective sides of the gas-liquid separating member, for supporting the gas-liquid separating member.

Abstract: A liquid discharge recording head is formed by bonding a recording unit, having plural recording elements for discharging recording liquid, with a recording liquid supply supporting member used for supplying recording liquid to the recording unit. The recording liquid supply supporting member is provided with at least one first snap fitting extending substantially in the same direction as the bonding direction of the recording liquid supply supporting member and the recording unit, and at least one second snap fitting extending in a direction intersecting the extended direction of the first snap fitting. The recording unit is provided with at least one first receiving portion engaging with the first engaging portion formed for the first snap fitting, and at least one second receiving portion engaging with the second engaging portion formed for the second snap fitting.

Abstract: A printhead assembly for an ink jet printer includes an elongate ink supply structure that defines at least one longitudinally extending ink passage and at least one set of holes in fluid communication with the at least one ink passage. A first ink chamber defining structure defines at least one ink chamber formation on one side and at least one set of ink inlet openings on an opposite side in fluid communication with the at least one ink chamber formation. The first ink chamber structure is engaged with the ink supply structure so that each ink inlet opening is in fluid communication with a respective hole of the ink supply structure. A second ink chamber defining structure defines at least one ink chamber formation on one side and at least one set of exit holes on an opposite side in fluid communication with the at least one ink chamber. The first and second ink chamber structures are engaged with each other so that respective ink chamber formations define at least one ink chamber.

Abstract: An inkjet cartridge for use with a thermal inkjet printer includes a standpipe area and an entrained ink chamber that are connected in fluidic communication. The entrained ink chamber and standpipe area can be enclosed by a wall that can have a plurality of panels or facets. The inkjet cartridge also includes a duct or passage that is connected in fluidic communication to both the standpipe area and the entrained ink chamber, wherein the connection to the entrained ink chamber is operatively located above the standpipe area, thus enabling anomalous air bubbles to migrate from the standpipe area and into the entrained ink chamber.

Abstract: A system for producing electrospray ions includes a thermal inkjet material dispenser configured to selectively emit a plurality of sample material particles, and an electrically conducting grid disposed in proximity with the thermal inkjet material dispenser, the grid being configured to permit a selective passage of the emitted sample material particles.

Abstract: The present invention provides a storing structure for storing an ink jet head comprising a nozzle communicated with an opening for discharging liquid, a liquid storing portion for storing the liquid to be supplied to the nozzle, and a liquid introduction portion for introducing the liquid into the liquid storing portion from exterior, wherein, in the ink jet head, air is housed in the liquid storing portion and the liquid is contained at least in the nozzle, and a cap unit including an elastic cap for covering an area of the opening and a liquid absorbing member disposed in the elastic cap is closely contacted with and attached, around the opening, to a face in which the opening is formed, and the liquid introduction portion is communicated with atmosphere at least when inner pressure of the liquid storing portion is increased, thereby maintaining a space within the cap unit to a wetting condition.

Abstract: An inkjet printer and inkjet print cartridge are each especially configured for inter-engaging with one another via a plurality of keying features of the cartridge and keying structures of the printer such that loading of a foreign print cartridge into the printer is either not possible or results in the printer being inoperative. Thus, only print cartridges particularly configured and intended to be used in the printer will fit into the printer and enable its operation.

Abstract: A liquid jet recording head includes a recording portion having a recording element substrate provided with a recording element for discharging liquid and a face surface provided with a discharge port for discharging liquid, a recording liquid storing portion for storing the recording liquid supplied to the recording portion, and a coupling member for coupling the recording portion and the recording liquid storing portion. A projecting member is provided on the recording liquid storing portion. The coupling member couples the recording portion and the recording liquid storing portion so that a leading end of the projecting member projects toward an end of the face surface from a side of the recording portion when the recording portion is coupled with the recording liquid storing portion.

Abstract: Multi-compartmentalized ink cartridges for ink jet printers and improved methods for making the ink cartridges. The multi-compartmentalized ink cartridge includes a molded, open-topped body having an interior cavity and a printhead surface area opposite the interior cavity. A divider wall is integrally molded with the molded body structure and disposed in the interior cavity to provide at least three segregated ink chambers. The divider wall includes a first wall section and a second wall section attached substantially perpendicular to the first wall section. At least first, second, third molded ink flow paths connect each of the at least three segregated ink chambers with the printhead surface area. The second and third ink flow paths are oriented relative to their corresponding ink chambers for molding with a mold insert tool so that the cartridge body does not require a separately attached member to close mold insert tool insertion areas in the body.

Abstract: An ink jet printhead assembly includes a heater chip having a backside with at least one cavity. A substrate is associated with the backside of the heater chip. Adhesive is at least partially disposed within the at least one cavity. The adhesive adheres the backside of the heater chip to the substrate.

Abstract: Techniques are disclosed for improving pressure sensor shock robustness in fluid containment devices by providing a mechanical filter configured to prevent high-frequency pressure shocks from damaging the pressure sensor. One approach includes a body of elastomeric material disposed on an external surface of the sensor. Another approach is a porous plug in a fluid pathway leading to the sensor. Yet another approach is to provide a seal structure with a labyrinth fluid path.

Abstract: In one embodiment an ink cartridge includes a housing defining a first fluid reservoir, and an expansible bladder defining a second fluid reservoir. The bladder is located within the first fluid reservoir, and includes opposing first and second wall members. The first wall member is fabricated from a material having a first shape-memory, and the second wall member is fabricated from a material having a second shape memory which is less than the first shape memory. In another embodiment a method of producing an expansible bladder includes providing a synthetic sheet fabricated from a material having a shape-memory, and folding the sheet in a generally “U” shape to produce first and second opposing wall members. Each wall member has two side edges and a top edge. The first and second wall members are sealed to each other along the side edges and top edges.

Abstract: In the liquid discharge recording head provided with a stopper member formed of an elastic member to be penetrated by a hollow needle member for liquid supply into a liquid preserving chamber in the recording head, the invention enables smooth insertion of the front end of the needle member into the stopper member without insertion failure. The liquid discharge recording head is provided with a head chip having a nozzle for discharging liquid, and a frame member connected thereto and having a liquid chamber for containing the liquid to be supplied thereto. A hole portion is formed in a portion of the frame member, and joint rubber is pressed into such hole portion. In the joint rubber, there is formed in advance a fissure hole, to be penetrated by a hollow needle provided in the main body of the liquid discharge recording apparatus and having fissures in not less than three directions from the crossing center of the fissures, in a plane perpendicular to the direction of depth of the hole portion.

Abstract: An inkjet cartridge for use with a thermal inkjet printer includes a free ink chamber with a tube disposed therein, wherein the tube defines therein an entrained ink chamber. The tube can extend from the top of the free ink chamber to the bottom thereof. The tube is preferably laterally enveloped by the free ink chamber. The tube has an interior surface on which a longitudinal channel can be defined, and wherein the channel can be helical.

Abstract: An air damper for use with an ink jet head has a main body having an ink reservoir portion, and a film sealed to the main body and covering the ink reservoir portion to define therewith an ink reservoir. A reinforcement plate is attached to the main body and overlies the film to prevent rupture of the film due to expansion thereof when the ink jet head is pressure-filled with ink. The reinforcement plate has a recessed portion opposed to and facing the film to permit limited expansion of the film caused by pressure fluctuations of ink in the ink reservoir.

Abstract: An ink tank cartridge includes a housing having a chamber defined by a set of side walls, a lid, and a first surface. An outlet port is formed in the first surface for communicating ink from the chamber. An ink receiving member for holding the ink is received in the chamber and is held in compression between the side walls. A substantial portion of the surface of the ink receiving member is compressed, preferably more than ?of the total surface. The ink receiving member is held uncompressed between the lid and the first surface. A method of assembling an ink cartridge includes providing a housing and a porous ink storage element. The ink storage element is compressed by a set of side walls defining a chamber formed in the housing. The ink storage element is compressed within a range of about 0.5%-50%.

Abstract: A printhead cartridge for use with an ink jet printer is disclosed. The printhead cartridge includes a memory element for storing jet characteristics of the cartridge. These characteristics can be measured during fabrication, upon installation into the printer, or during the operation of the printer. The printer adjusts printing parameters to compensate for the out of specification characteristics for optimized image quality. The compensation is done through adjusting drop ejection energy, thermal control, or replacing failed jets with substitute jets in the printhead. Alternatively, the printer accesses the measured characteristics to determine if they are within specification. If the printhead cartridge does not meet specifications, the user is instructed to remove the printhead cartridge since its use may adversely affect the quality of the resulting image. The printer accesses the measured characteristics throughout the life of the cartridge to ensure the quality of the resulting image does not degrade.

Abstract: A liquid ink cartridge, such as ink jet ink cartridge, includes a container defining an ink reservoir, the ink reservoir having an ink outlet at one end and capable of receiving a supply of ink in the ink reservoir; and an ink follower composition located in the ink reservoir apart from the ink outlet. The ink follower composition includes a viscous gel material that provides a negative pressure in the ink reservoir.

Abstract: The present invention prevents liquid leakage regardless of the using conditions and the reserving atmosphere and stabilizes a negative pressure regardless of the degree of liquid consumption, by having a one-way valve in the liquid container that supplies liquid to an external device, maintaining the negative pressure formed in the liquid supplying passage positioned in the downstream of a position where liquid or gas is supplied by the one-way valve. The liquid container has a deformable, movable unit at least a part of which is made of a flexible material. A space other than the liquid supply unit forms a substantially sealed space in which liquid is retained. The container is capable of supplying the liquid to the outside. Such container has a one-way valve that passes liquid or gas from the liquid container to the outside or from the outside to the liquid container.

Abstract: A polyurethane foam compound for an ink holder, characterized in that it comprises a polyol and an isocyanate as main components, and also a crosslinking agent; an ink holder, characterized in that it is prepared by foaming, curing and crosslinking the compound; a method for securing the close contact of an ink holder, which comprises using the above described ink holder, and placing the ink holder in an ink tank for containing an ink in a manner such that the ink holder is attached to the inner wall of the ink tank.

Abstract: A liquid container which is in detachably connectable to a supply tube which is in fluid communication with a liquid ejection recording head, the liquid container including a liquid accommodating portion for accommodating liquid to be supplied to the liquid ejection recording head and a supply port for permitting supply of the liquid to the recording head from the liquid accommodating portion by connection of the liquid container to the liquid ejection recording head, the liquid container includes a capillary force generating member for generating a capillary force to absorb the recording liquid deposited on the surface of the supply tube and in the supply port into a space, other than the liquid accommodating portion, in the liquid container; wherein a capillary force A generated in an absorption region for absorbing the recording liquid remaining in the supply port adjacent the supply port of the capillary force generating member and a capillary force B in a storing region for storing the recording liquid a

Abstract: A single-piece print cartridge body is provided. The print cartridge has a plurality of outlet ports disposed along a single axis that is substantially perpendicular to a direction of motion of the print cartridge body during printing. First and second compartments are respectively communicatively coupled to first and second cavities. The first and second cavities are substantially parallel to the single axis and are located on opposite sides of the single axis. A first channel interconnects the first cavity and a first one of the plurality of outlet ports. A second channel interconnects the second cavity and a second one of the plurality of outlet ports. The first and second channels are substantially perpendicular to the single axis.

Abstract: An ink tank of the foam type which is provided with a detected portion capable of exactly and surely detecting the amount of ink used by the printer or remaining in the ink tank. The ink tank includes a sub ink chamber that is diposed or formed between a main ink chamber and an ink outlet of an ink tank of a foam type. When an amount of air flowing into the sub ink chamber increases, one or more reflecting surfaces of a right-angled prism, which function as ink interfaces, resume their original function of reflecting surfaces, thereby enabling the detection of an ink end. Air bubbles having entered the sub ink chamber are surely led onto the one or more reflecting surfaces by a bubble storage part. At an ink passage having a narrow width, which is defined by the one or more reflecting surfaces, air bubbles are pressed against the one or more reflecting surfaces to be put to a crushed state and in surface contact with the latter.

Abstract: A cartridge for a digital printer adapted to print information onto a media substrate in a form that can be read by the human eye and a form that is invisible to the human eye but readable to an optical reader device. The cartridge includes a housing defining a number of storage areas wherein at least one of the storage areas contains colorant for printing information that is visible to the human eye and at least one of the other storage areas contains colorant for printing information in a form that is invisible to the human eye but readable by the optical reader device. The colorant for printing information in a form that is invisible to the human eye but readable by the optical reader device is infrared absorbing ink.

Abstract: An ink cartridge for an ink jet printer is provided. The provided ink cartridge has an ink reservoir and a housing for covering the ink reservoir with a negative pressure maintenance unit therebetween, to maintain the inner pressure of the ink reservoir under a negative pressure. Since the negative pressure maintenance unit does not contact ink in the ink reservoir, the negative pressure maintenance unit does not corrode. In addition, the negative pressure maintenance unit is installed between the housing and the ink reservoir while occupying a small space, and thus improving the filling efficiency of ink in the ink reservoir.