KR100520535B1 - Ink container - Google Patents

Abstract

Low ink detection systems are combined with ink cartridge detection systems to operate inkjet printers more efficiently. The ink container for supplying ink to the associated printhead is modified by incorporating two light directing members, in a suitable embodiment, a multi-sided prism and a loop mirror, into the transmissive wall of the container housing. A cartridge containing a printhead associated with an ink container is mounted on a scan carriage. Periodically, the carriage is carried to a sensing station that includes a pair of light sources and a light sensor commonly used. The first light source is excited and the light beam is directed to the location where the loop mirror is located if a carriage is present. If no carriage is present, a lack of reflected return signal is detected indicating that the carriage is not inserted. The printing operation is stopped until the carriage is inserted. When the carriage is properly inserted, the loop mirror returns most of the light sensor incident light that generates a signal indicating the presence of the carriage. The second light source is then excited and directed towards the prism if it is immersed in ink or exposed to air inside the container. In the latter case, the light is integrally reflected by the prism facet to the light sensor. As the printing operation proceeds and the ink level is depleted, the common light sensor detects strong or weak redirecting light components and initiates a status check and generates a warning of a suitable indication of low ink level or ink depletion.

Description

Ink container

The present invention relates to an ink jet recording apparatus, and more particularly, to a system for detecting the presence of an ink supply container and for detecting whether an ink level in the container is at or below a predetermined level.

An ink jet recording apparatus ejects ink onto a print medium such as paper in a control pattern of closely spaced dots. In order to form a color image (image), multiple groups of inkjets are used, and each group is supplied with inks of different colors from the associated ink container.

Thermal inkjet printing systems use thermal energy selectively generated by a resistor placed in a capillary filling ink channel near channel end nozzles or orifices to instantaneously evaporate the ink and form bubbles on demand. do. Each temporary bubble releases ink droplets and propels them toward the recording medium. The printing system can be incorporated into either a carriage type printer or a pagewidth type printer. Carriage-type printers generally have a relatively small printhead that includes ink channels and nozzles. The printhead is typically sealedly attached to an ink supply container, and the combined printhead and container are cartridges that reciprocate to temporarily print a row of information on a fixedly held recording medium such as paper. To form an assembly. After the rows have been printed, the paper is stepped by a distance equal to the height of the printed rows so that the next row to be printed is in contact with the paper. This procedure is repeated until the entire page is printed. In contrast, a page width type printer has a stationary print head having a length equal to or greater than the width of the sheet. Paper continuously moves past the page width printhead in a direction perpendicular to the printhead length at a constant speed during the printing process. The mobile carriage inkjet printer must move the ink container with the printhead or provide a flexible ink supply line between the mobile printhead and the stationary ink container. The pagewidth printer has an ink supply container located outside the printing area and directly connected to a printbar ink channel.

For a partial width printhead or pagewidth print bar on a movable carriage, it is desirable to have a low ink level warning to warn the user to replace or refill the ink container so that ink is not depleted during the print job. . For some applications now (such as plotting), some users start many print jobs because it is less expensive to replace the offending container than one or more colors are missing from the printed output. We are choosing to install a new printing container before. It is also important to ensure that the ink supply container is fluidly connected to, for example, the associated printhead in a suitable position. In some cases, the depleted ink container can be removed but neglected to insert a replacement container. Printing with the container removed can seriously damage the associated printheads.

Various prior art methods and apparatus are known for detecting reduced levels of ink in an ink supply container. U. S. Patent No. 4,342, 042 discloses an ink sensing system that includes an output from an LED sensor that is reflected in a flexible thin film that serves as the top surface of an ink supply reservoir. The thin film shrinks when the ink is depleted, and the LED sensor detects the shrinkage and generates a low ink level signal.

U. S. Patent No. 5,079, 570 provides a method for detecting the ink level of an ink cartridge from which ink is supplied from a foam reservoir. The dual flow indicator is fluidly coupled with the foam reservoir, and the fluid level in the foam is triggered when it reaches any prescribed level.

U. S. Patent No. 5,289, 211 discloses a low ink detection system comprising a pair of electrodes immersed in an infiltrated foam reservoir. The electrodes are connected to a bridge circuit that measures the electrical resistance of the ink between two electrodes.

US Pat. No. 5,414,452 uses a logic circuit to calculate the number of droplets released and to compare the number with the maximum number of droplets corresponding to a known value of the ink in the ink reservoir.

U.S. Patent 5,434,603 discloses a visible indicator system in which the side wall of a reservoir shrinks inward during ink depletion, changing the orientation of the indicator strips and changing color visibility to the viewer through the window.

U. S. Patent No. 5,386, 224 places a level sensing probe in the supply of ink to sense a change in conductivity of the ink.

U. S. Patent No. 5,136, 305 discloses a low ink detection system in which a thermistor is located at the ink supply and periodically excited. The temperature rise of the ink is measured and compared to a predetermined value to determine the ink depletion condition of the reservoir.

U. S. Patent No. 4,639, 738 discloses a detection system incorporating a detection port in a cartridge to detect pressure conditions at the top and bottom of the cartridge. The port is coupled to a differential pressure sensor that sends a recharge condition signal.

Japanese Patent Laid-Open No. 5-332812 discloses a low ink detection system having a transparent optical path member in which a cartridge is installed in an opening of an ink storage tank surface. The LEDs are guided into the ink tank and emit light beams that are reflected and reach the sensor to provide an indication of low ink levels.

Some prior art is relatively expensive because it relies on the measurement and detection or drop detection circuitry of ink conductivity. In addition, none of the prior art includes means for ensuring that the ink tank is in a suitable position before starting the ink level sensing operation.

Therefore, it is an object of the present invention to provide a detection system that ensures proper mounting of an ink container for supplying ink to an associated printhead.

Another object of the present invention is to provide a detection system that detects a low ink level in an ink container and provides a low ink level warning signal.

It is a further object of the present invention to provide an ink supply container configured to enable a low cost optical detection system that performs both the detection of the ink container as well as the low ink level detection function.

In an exemplary embodiment of the present invention, a thermal printer is disclosed that includes a printhead for printing onto a recording medium in response to an image drive signal. Ink is supplied to the printhead from an ink container fluidly connected to the printhead. The printhead and the container are mounted in a scanning (scanning) carriage moving horizontally across the print area, and the printhead discharges ink droplets from the nozzle to form an image on the recording medium. An optical system comprising two light sources and a photodetector is rigidly disposed along the path of travel of the carriage and positioned so that light from the light source is directed to the ink container when the ink container is positioned opposite the optical system. The ink container has an optical light directing member formed in a transmissive wall. Light from the light source is directed through the transmission wall into and onto the container, and then onto the optical member. In one embodiment, the light directing member is a reflective prism and the reflection or lack of light from the member is sensed by a common light sensor to provide a signal indicative of the presence or absence of the container and the level of ink remaining in the container.

In more detail, the present invention relates to an ink container, wherein the ink container,

A housing surrounding the inner space,

An ink outlet passing through the first wall of the housing in the interior space;

Regardless of the amount of ink in the inner space, the light directing member is disposed on the second wall of the housing and directs the received light in a direction away from the second wall of the housing.

The present invention also relates to an ink container for a liquid ink printer, wherein the ink container is

A housing having a plurality of walls surrounding the interior space,

Liquid ink in the inner space,

A liquid ink outlet through the first wall of the housing to be in fluid communication with the inkjet printhead, and

A loop mirror having first and second reflectors outside of the second wall of the housing,

The first reflector completely reflects light received by the first reflector towards the second reflector, the second reflector being on the optical path parallel to and eccentric from the path of light received by the first reflector Completely reflects light received by the second reflector spaced from the second wall of the housing.

The present invention also relates to a method for detecting the presence or absence of a cartridge mounted on a movable cartridge and used in an inkjet printer, and a method for detecting an ink level in an ink container associated with the cartridge.

Directing the light beam into the light sensing station;

Moving the cartridge into a light sensing station to intercept the light beam if part of the cartridge is present;

Detecting the presence or absence of light redirected rearward from a portion of the cartridge;

Generating a signal indicating the presence or absence of a cartridge.

The present invention also relates to a system for detecting the presence or absence of an ink cartridge in an ink recording apparatus, wherein the cartridge includes a printhead and an ink container for supplying ink to the printhead.

At least one printhead for printing each of the first colors on the recording medium;

An associated ink supply container for providing ink of a first color to the printhead, the associated ink supply container having an at least partially transparent section of a wall having at least one reflective member associated with each other;

Means for moving the cartridge along a scanning path;

An optical sensing station disposed along the scanning path and including a light source and an optical sensor;

Means for moving the cartridge into the station so that the reflective member can face the light source output if the cartridge is physically present, and

And means for exciting the light source, wherein the optical sensor indicates the presence of a cartridge to detect the light source output beam reflected from the reflective member, or the lack of reflected light to indicate the absence of the cartridge.

1 is a perspective view of a thermal ink jet printer 8 embodying a suitable embodiment of the ink container and low ink detection system of the present invention. The printer 8 is merely exemplary. The present invention can be implemented not only with other types of thermal inkjet printers, but also with other reproducing apparatuses such as piezoelectric printers, dot matrix printers, and inkjet printers driven by signals from a document Raster Input Scanner. The printer 8 comprises an inkjet printhead cartridge 10 mounted on a carriage 12 supported by a carriage rail 14. The carriage rail is supported by the frame 15 of the inkjet printer 8. The printhead cartridge 10 includes a container 16 as shown in detail in FIG. 2, which is configured to receive electrical signals received via an electrical cable 20 from a controller 50 of the printer 8 (FIG. 4). Ink for supplying to a thermal inkjet printhead 18 that selectively releases ink droplets under control. The container 16 comprises a housing 17 with a wall 17A on which the reflecting members 21, 22, shown in more detail in FIG. 2, are mounted. The container 16 is fluidly detachably connected to the printhead 18 and can be replaced when the ink is depleted. In addition, the entire cartridge can be replaced upon each depletion, depending on the particular system requirements. The printhead 18 includes a plurality of ink channels that carry ink from the vessel 16 to respective ink ejection orifices or nozzles. In printing, the carriage 12 reciprocates laterally along the carriage rail 14 in the direction of arrow 23, and the transversal of the full width constitutes the scanning path. The actual print area is included in the scanning path. As the printhead cartridge 10 moves back and forth along the printing path and passes through a recording medium 24 such as a sheet of paper or transparencies, ink droplets from the selected one of the printhead nozzles toward the sheet of paper. Is released. Typically, during each passage of the carriage 12, the recording medium 24 remains fixed. At the end of each passage, the recording medium 24 is line-shifted in the direction of arrow 26. For a more detailed description of printer 8 operation, see US Pat. No. 4,571,599 and Reissued US Pat. No. 32,572, which are incorporated herein by reference.

1 also shows an optical sensing assembly 30. 1 and 2, the assembly 30 is a first light source 34, a second light source 36, and an optical sensor 38 disposed between and generally used with the two light sources. Is mounted to the housing 31. The light sources are electrically connected to a power source, while the output of the light sensor 38 is electrically connected to a system controller circuit. In a suitable embodiment the vessel 16 is designed as two compartment units. The assembly 30 is mounted in the carriage path so that when the housing wall 17A of the container is moved to a position opposite the assembly 30, the light from the light source 34 is directed towards the light directing member 21. , Light from the light source 36 is directed towards the light directing member 22. The light sensor 38 is positioned to detect light directed from the light directing member 21 or 22 in the manner described in more detail below.

FIG. 2 is a cross-sectional view of the printhead cartridge 10 along line 2-2 of FIG. 1, showing the housing 17 and the printhead 18 attached to the container. The print head 18 is fluidly detachably connected to the container 16. The housing 17 is made of lightweight but durable plastic, and in a suitable embodiment is made of polypropylene. The housing 17 has an air inlet 32 and an ink outlet 35 formed in the wall 17B. The air inlet 32 is installed to transfer air between the interior and the surroundings of the housing 17. The ink outlet 35 is provided for fluid transfer of the ink stored in the ink container 16 from the inside of the housing 17 to the inkjet printhead 18. The manifold 37 directs the filtered ink from the ink outlet 35 into the printhead 18 and into the ink ejection orifices for ejecting ink on the recording medium 24.

The housing 17 forms an inner space divided by the partition member 44 into the first chamber 40 and the second chamber 42. The partition member 44 extends from one sidewall of the housing 17 to the opposite sidewall of the housing, and extends the housing into the first chamber 40 such that the second chamber 42 is larger than the first chamber 40. And essentially divided into a second chamber 42.

The first chamber 40 includes an ink holding member 46, which is usually made of foam material to hold liquid ink. The liquid ink 48 stored in the second chamber 42 is the ink holding member 46 through the ink inlet 41 formed by the partition member 44 from the second chamber 42 having substantially no ink holding material. Is delivered to. The charging port 49 allows to charge ink in the cartridge.

Ink 48 passes through the ink inlet 41 to the ink holding member 46 and supplies ink to the printhead 18 for printing and discharges through the ink outlet 35 as necessary. In order to hold an amount of ink in the ink holding member 46 suitable for supplying the printhead 18, the housing 17 is topped with liquid ink 48 to fill the member 46 with ink as needed. And a mechanism for delivering ink from the second chamber 42 to the first chamber 40 by maintaining an amount of air pressure suitable for the second chamber 42. The mechanism comprises a directing member 63 which forms an air delivery passage 62 together with the partition member 44, which air passage 62 is in a static (flow-free) state with the second chamber 42. It has a vent inlet 64 coupled to a vent outlet 66 to pressurize it. The directing member 63 does not extend from one side wall to the opposite side wall like the partition member 44 but instead forms a vent tube.

The structure of the compartment of the container 16 demonstrated so far is illustrative. There is another known method of constructing an ink supply container having a divided section while maintaining a suitable back pressure to the printhead nozzle. See, for example, the container disclosed in US Pat. No. 5,138,332, co-filed with US Pat. No. 5,138,332, which is incorporated herein by reference. According to the object of the present invention, the container is configured such that during operation, ink is transferred from the chamber 42 to the chamber 40 through a passage between two compartments under pressure conditions established by techniques known to those skilled in the art. You have to understand. What is important for the present invention is that a change to the ink container 16 is made by introducing the light directing members prism 21 and the loop mirror 22 into the wall 17A forming the rear of the chamber 42.

With particular reference to FIG. 2, in a suitable embodiment, the light directing member 21 is integrally formed in the lower half of the wall 17A and is the same light transmitting material as the wall, for example polypropylene in a suitable embodiment. It is a reflector made of the same material. Polypropylene, or other hydrophilic materials are suitable. The prisms consist of facet surfaces 21A and 21B extending into the compartment 42 and angled towards each other at an angle of about 82 degrees. The prism has a truncated pyramidal shape with surfaces 21A and 21B connected by the facet surface 21C. The prisms can be composed of a number of narrow facet sections to avoid concave sinks that typically occur when injection molding large sections, and to provide improved light piping.

The light directing member 22 is also formed as part of the wall 17A. In a suitable embodiment, the member 22 is a prism having two facet surfaces 22A, 22B extending into the compartment 42 and angled towards each other and connected by the surface 22C. The member 22 is formed of a loop mirror by placing reflective films, foils, or tapes 22D, 22E, respectively, on surfaces 22A, 22B.

It is understood from the above that only a part of the wall 17A, for example only a portion containing the reflective member 21, needs to be transparent. Further, although in a suitable embodiment, there is a reflective member integrally formed with the housing wall, the member may be separately located adjacent to the inner surface of the wall 17A.

Detection system operation

The sensing system of the present invention contemplated to include a combination of reflective members 21, 22 and optical assembly 30 provides for the presence of low volume ink and the presence of an ink container after a specific operation, such as after the start of a print job or after the printing of a predetermined amount of prints. It is designed to perform level checking. To perform this check, the printer follows an algorithm that requires the ink container to be positioned adjacent to the assembly 30 and sequenced through a series of detection steps. 3 is one embodiment of an algorithm to be used. 4 shows a control circuit for implementing an ink container and an ink level sensing system. Typically, the main controller 50 includes a CPU, a ROM for storing a complete program, and a RAM. The controller 50 controls the movement of the carriage 12 as well as other printer functions described below.

When a line write operation is executed, each resistor associated with a jet at the printhead 18 is optionally dependent on the image data sent to the controller 50 from the personal computer P / C 52 or other data source. Driven. The controller 50 forms a line to record on the surface of the recording medium 24 by sending a drive signal to the printhead heater resistor to discharge ink droplets from the jet associated with the heated resistor. With the continuous operation of the printhead, the ink contained in the chamber 42 of the vessel 16 is gradually depleted until a predetermined level is reached to set the low ink level.

For the sake of explanation, the sensing system is first considered to be activated at the start of a print job and after a predetermined period of printer operation.

Operation at the beginning of a print job

1-4, the image signal from P / C 52 to controller 50 begins a start print sequence. The carriage 12 is moved to the sensing station to position the housing wall 17A of the container 16 to face adjacent to the optical assembly 30. Under the control of the controller 50, the power source 56 first excites the light source 36. In a suitable embodiment, the light source 36 is an LED having a peak wavelength in the range of 880-940 nm. The beam of light is directed towards the housing wall 17A, and if present, the light is reflected from the reflective surfaces 22D, 22E of the roof mirror 22 and redirected onto the light sensor 38. . The two reflective surfaces allow the beam to step vertically downward to avoid being higher than an acceptable angle of incidence at the detector. The output signal from the optical sensor 38 is transmitted to the logic circuit in the controller 50 which determines whether there is a signal within a preset range. The controller is then sequenced to drive the first light source 34.

If the container 16 is not present, the light output of the light source 36 will not be reflected to the light sensor 38. The lack of output from the light sensor will be recognized by the computer in a "container free" state. P / C display to remind the user that the printer will be unusable, a) to prevent printing of the color associated with the missing tank, and b) to have the correct container installed to prevent potential damage to the printhead. At 55 the warning indication will be activated.

In a suitable embodiment, the light source 34 is also an LED having similar characteristics as the light source 36. The light source 34 is transmitted through the wall 17A and emits light beams incident on the facet surface 21A of the prism 21. 5A is a cross sectional view of the prism 21 and is a schematic diagram of the assembly 30 showing the path of the light beam when the prism is continuously immersed in ink, so that the level of the ink exceeds the preset low level. .

Low ink detection is made possible by applying the principle of total internal reflection. Total reflection occurs when a light ray passing from a high refractive index to a low refractive index (from N to N ') has an angle of incidence greater than sine N' / N. The critical angle I _c is represented by the following equation.

I _c = arc sin N '/ N (1)

As shown in FIG. 5A, the output light beam of the LED 34 passes through a wall 17A composed of polypropylene and having a refractive index of about 1.492 and which transmits light almost completely, yielding about 96% of incident light. Passes through and is incident on the facet surface 21A at an angle of incidence of about 45 °. Since the rear face of the surface 21A is immersed in an ink having a refractive index of about 1.33 and does not reach a critical angle, about 99% of incident light is transmitted to the ink at a refractive angle of about 51.4 °, and only approximately <1% is the facet surface. Reflected by 21B. Since the inner facing surface of the facet surface 21B is also immersed in ink,> 99% of the 1% is transferred to the ink. Only a very small (about 0.01%) of the original incident energy is reflected towards the light sensor 38. The output signal from the light sensor at the controller 50 will register a low light level that is outside the low ink level preset range set in the controller memory. The controller compares this signal with the signal from the previous state to determine if the previously identified container should be replaced or refilled if in a low ink state. Then, the status log is set or reset to the "non-empty" level and the controller 50 allows the printhead drive circuit 61 to send a drive signal to the printhead to begin the print sequence. do. The low ink level threshold for this embodiment is set to 20% of the fill level of the container.

Summarizing the operation of the detection system thus far, the presence of the ink container is confirmed. In addition, it is confirmed that the ink in the container is equal to or more than a predetermined level, and thus the printing job can be started. The ink level sensing system operation will be described in the second time setting to occur after some predetermined operating time.

Operation during a print job

When the printer 8 starts printing a print job corresponding to the image input signal from the P / C 52, the ink is drawn from the foam in the compartment 40 (FIG. 2) to reduce the saturation of the foam. Flow paths are formed that allow ink from compartment 42 to refill the foam. Thus, the ink level in the compartment 42 gradually decreases during use of the printer. The low ink check will begin after a certain number of pixels, for example a 7x10 ⁶ pixel, has been printed by any one color at the end of each print job or after the last check. For illustrative purposes, it is assumed that the print job is terminated by lowering the ink level in the compartment 42 to a point below the predetermined trip point level shown by dashed line 80. The low ink level detection procedure begins at this point.

Continuous printing is interrupted and, as described above, the carriage 12 is moved to a position where the housing wall 17A and the prism 21 oppose the sensing assembly 30. The controller again sequences through the excitation of the light sources 34, 36 (vessel detection can be omitted). 5B shows the effect of low ink levels on light beams. Light from light source 34 passes through wall 17A and is incident on facet surface 21A at an angle of about 45 °. When the ink level is reduced to less than 20% of the filling level, the ink no longer contacts the rear face of the facet surface 21A exposed to the air having a refractive index of 1.0. The critical angle of 42.9 ° is exceeded by the incident light on the facet surface, so that incident light is not transmitted through the surface. The light beam is reflected back into a denser medium that produces total beam internal reflection (TIR) as a whole. The entire incident energy is reflected toward the facet surface 21B. Since the rear face of the facet surface is exposed to air, the entire energy is directed backward towards the optical sensor 38. About 92% of the incident energy (negative absorption) is returned to impinge on the optical sensor 38. The output signal from the light sensor is recognized by the controller logic when within the preset low ink level range. The controller performs a state check to see if the change from the previous state has changed from "not empty" to "empty". Since this is a case of a temporary example, the state log memory of the controller 50 is set to the "empty" state, and a low ink level signal is generated and displayed on the P / C display 55. The low ink signal may indicate that the ink level is simply displayed by the operator, stop printing operations until cartridge refilling or replacement is performed, or continue to run the job in a suitable embodiment or "low ink" state, depending on the requirements of the system. It is used to change it. As shown in Figs. 3 and 4, the controller sends a signal to the P / C 52 indicating a suitable warning for specifying that the ink in the immediately checked ink container is small. Each ink container contains a residual amount of ink that can be correlated with the number of residual pixels (or drops). This number may be different for each ink color. The low ink signal generated in the controller logic uses the counter 60 to count the number of pixels (drops) emitted from the printhead ejection and the reduction of ink introduced into the ink tank. When the preset number of pixels is counted, the ink tank is defined as ink depletion, and printing is automatically stopped. Termination occurs before the tank is completely depleted (level of about 2-5%) to ensure that the printhead and its ink channel lines are not empty and not jeopardize the reliability of the printhead. During the time between the first detection of low ink and the ink depletion determination, an emergency message can be displayed on the P / C display. The pixel value of the residual ink depends on the frequency of the low ink check.

The scenario assumes that the prism 21 is completely immersed in the ink or completely out of the ink. Between these two cases, there is a transition that appears by monotonically increasing the light level with respect to the signal from the LED 34 when the facet surface 21A is gradually exposed to a lot of air by the ink level. 6 is a graph of the sensor output in volts versus milliliters (ml) of ink transferred to the printhead. For the first 70% of the transferred ink, the sensor current is low and the voltage output across the comparison circuit of the controller 50 is high. In the depletion between 70% and 75%, a rapid transition occurs where the LED 34 output beam begins to totally reflect from the facet surfaces 21A and 21B of the prism 21, thus reducing the output current from the sensor 38. Increase to produce a rapid voltage drop in the circuit.

The present invention can be used in other types of inkjet printing systems including full color printers. 7 shows a full color scanning printer. Referring to FIG. 7, a thermal inkjet printer 70 is shown. A plurality of ink supply cartridges 72, 73, 74, 75 each having integrally attached thermal printheads 76-79 are mounted on a translationally movable carriage 77. During the printing mode, the carriage 77 reciprocates in left and right directions on the guide rail 78 in the direction of arrow 81. For example, the recording medium 79 such as paper is kept fixed while the carriage is moved in one direction, and before the carriage is moved in the opposite direction, the recording medium is printed on the recording medium by the thermal printhead. It is line-shifted at a distance equal to the height of the stripes of the data. Each printhead has straight array nozzles aligned in a direction perpendicular to the reciprocating direction of carriage. The thermal printhead discharges ink droplets 83 toward the recording medium whenever the droplets are required to print information during the carriage. Signal transmission ribbon cables attached to the terminals of the printhead are omitted for clarity. The printer 70 is printed in multiple colors, and each cartridge 72 to 75 includes a different color ink supply. For exemplary color printers and additional control details, see, for example, US Pat. No. 4,833,491, incorporated herein by reference.

According to the present invention, each of the ink containers forming part of the cartridges 72 to 75 has the same configuration as the cartridge shown in Fig. 2, and for the purposes of the present invention, each cartridge has two outwardly facing walls formed therein. It has an ink container having prismatic reflectors. One reflector is associated with cartridge presence detection and the other reflector is associated with low ink detection. The cartridge 72 is shown having an ink container 80 having reflective members 82 and 84. Although not shown for clarity, the cartridges 73 to 75 have similar containers and reflective members. As in the embodiment of a single cartridge, the sensing assembly 90 has a housing 92 equipped with a first light source 94 and a second light source 96 and an optical sensor 98 disposed between the two light sources. It includes.

In operation, referring to FIGS. 4, 7 and 8, an image signal from P / C 52 to controller 50 initiates a start print sequence. The carriage 77 moves the cartridge 72 with the first ink container 80 to be positioned opposite the sensing assembly 90. Under the control of the controller 50, the power source 56 in turn excites the light sources 94, 96 while measuring the output of the optical sensor 98. Sequencing and detection operations of the cartridge 72 are the same as described above for the cartridge 10. The light source 96 is first excited to check if a cartridge is present (if the reflected light from the loop mirror 84 to the light sensor is within range), and then the light source 94 is turned on so that the ink level in the container system is It is determined after comparison with the state. {The reflected light from the front surface of the prism 82 is detected by the optical sensor 98.} When the inspection of the cartridge 72 is finished, the carriage 77 moves to be positioned at the position to detect the next cartridge 73. do. The preceding process is performed for each cartridge until all cartridges are in place and all ink levels in the assembly ink container are within acceptable levels or a suitable low ink level warning is indicated on the P / C. Can be.

While the embodiments described herein are suitable, it should be understood by those skilled in the art that various changes, modifications, or improvements may be made. For example, detection of the presence or absence of the ink container can be achieved using other light directing members. One example is the light pipe shown in FIG. 9 shows a portion of a container 16 ′ having an optical member 22 ′ disposed outside the housing wall 17A ′. The member 22 'is a curved light pipe for redirecting the light inlet end 22A' and the light outlet end 22B 'to the light sensor 38'. Optionally, the optical member 22 ′ may be an optical fiber. In both the above embodiments, the same function as the reflective member 22 of FIG. 2 is performed. If the vessel is present, a high current is generated at the light sensor 38 '.

The light transmissive embodiment is suitable for some systems because the reflective foil or tape used to form the loop mirror 22 for the embodiment of FIG. 2 does not adhere well to the prism facet surface.

Although the optical assembly 30 of FIG. 1 is considered optimal, other devices of the light sensor and light source of the assembly may also be used in accordance with the present invention. One example is the use of one light source and two light sensors shown in FIG. As shown, the optical assembly 100 includes first and second optical sensors 102 and 104, the output of which are read by a controller. The LED light source 106 is connected to a power source. The vessel detection operation is the same as described above. The light level is sensed by the light sensor 104 and an appropriate signal is sent to the controller. Similarly, low ink readings are made at the sensor 102. In this embodiment, the LEDs can be operated continuously or intermittently (pulsed).

Other efficient arrangements are possible where the light source and the sensor are associated with the respective reflecting members 21, 22 of FIGS. 1 and 2 (not shown).

As another example, the embodiment of FIGS. 1 and 7 shows an ink container mounted on a scanning carriage that periodically moves to a detection station, while the ink container can be placed in a fixed position and the flexible ink It can be connected to the scanning printhead via a supply line. In the case of the embodiment of FIG. 1, the container 16 is fixed in a position opposite the optical assembly 30 and can be connected to the printhead 18 through a flexible tube. In the case of the embodiment of FIG. 7, four optical assemblies can be disposed outside of the opposite print area from the associated ink container, each of the ink cartridges being connected to each printhead cartridge via a flexible ink coupling. Can be. For example, in the case of a full width array printhead of the type disclosed in US Pat. No. 5,221,397, the ink container spaced apart is an ink manifold that connects ink with a plurality of input modules joined together to form a full width array. Is connected to. One or more optical assemblies may be placed opposite the modified ink container.

According to the present invention, there is provided a detection system capable of reliably assuring proper mounting of an ink container for supplying ink to an associated printhead, detecting a low ink level in the ink container, and providing a low ink level warning signal. It is possible to provide an ink supply container configured to be capable of performing a low ink level detection function as well as ink container detection with a low cost optical detection system.

1 is a perspective view of an inkjet printer incorporating an ink container and a low ink level detection system of the present invention.

FIG. 2 is a cross-sectional view of the ink cartridge shown in FIG. 1. FIG.

3 is an algorithm used to sequence checks by determining the level of ink in a container as well as the presence or absence of a container.

4 is a block diagram of a control circuit for controlling the operation of the sensing system.

Fig. 5A is a cross sectional view of the prismatic reflective member in the cartridge showing the prism container having a sufficient level of ink;

5B is a cross-sectional view of the prism of FIG. 5A showing the reflection path in a low ink level environment.

6 shows a plot of a low ink sense output signal against the volume of ink depleted from a cartridge.

7 is a perspective view of a full color inkjet print incorporating the ink container and low ink level detection system of the present invention.

8 is an algorithm used in the embodiment of FIG. 7 to sequence the presence of a container and then low ink level sensing.

9 illustrates another embodiment of a cartridge detection system incorporating a light pipe.

FIG. 10 illustrates another embodiment of the optical assembly shown in FIGS. 1 and 2.

※ Explanation of code about main part of drawing ※

10 cartridge 16: container

17: housing 21, 22: reflective member

24: recording medium 30: optical assembly

34, 36: light source 38: light sensor

50: controller 55: P / C display

70: printer 72-75: cartridge

82, 84: reflective member 92: housing

Claims (10)

A housing 17 surrounding the inner spaces 40 and 42, An ink outlet 35 passing through the first wall 17B of the housing in the interior space; Regardless of the amount of ink 48 in the interior space 42, the light irradiated from the light source 36 and positioned on the second wall 17A of the housing is directed away from the second wall of the housing. And a light directing member 22 for directing to the optical sensor 38, characterized in that the light directing member 22 consists of a loop mirror which is a reflector having first and second reflective surfaces angled towards each other. Ink container. The ink container according to claim 1, wherein the reflector is mounted outside of the second wall of the housing. 3. The reflector of claim 2, wherein the reflector comprises first and second reflectors external to the second wall of the housing, the first reflector fully reflecting light received in the first reflector towards the second reflector And the second reflector completely reflects light received in the second reflector in a direction away from the second wall (17A) of the housing. 4. An ink container according to claim 3, wherein at least a portion (21) of said second wall is light transmissive. 2. The light directing device of claim 1 wherein the light directing member 22 comprises a plurality of reflectors, the reflectors having a second path in which light on a first path incident on a first reflector of the reflectors is eccentric from the first path. And an ink container disposed to be reflected from a second of the reflectors along the surface of the reflector. A housing 17 surrounding the inner spaces 40 and 42, An ink outlet 35 passing through the first wall 17B of the housing in the interior space; Regardless of the amount of ink 48 in the interior space 42, the light irradiated from the light source 36 and positioned on the second wall 17A of the housing is directed away from the second wall of the housing. And a light directing member (22) for directing to an optical sensor (38), said light directing member (22) being a curved light pipe (22 '). A housing 17 having a plurality of walls 17A, 17B surrounding the interior spaces 40, 42, Liquid ink 48 in the interior space, A liquid ink outlet 35 through the first wall 17B of the housing for fluid communication with the inkjet printhead, and A loop mirror 22 having first and second reflectors outside of the second wall 17A of the housing, The first reflector completely reflects light received by the first reflector toward the second reflector, the second reflector paralleling the light path received by the second reflector to an optical path of light received by the first reflector And an ink container for completely reflecting in a direction away from said second wall of said housing on an optical path eccentric from said path. 8. An ink container according to Claim 7, further comprising a printhead (18; or 76 to 79) having fluid conduits and ink ejection orifices connected to said liquid ink outlet of said ink container housing. The ink container according to claim 8, wherein the printhead is detachably connected to the container housing. 8. An ink container according to Claim 7, wherein said container is attachable to a printhead (18; or 76 to 79) comprising ink ejection orifices.

Images