Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2000-11-27
2002-08-06
Hallacher, Craig (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06428132
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a method and arrangement for determining the number of normal imprints implementable with a remaining ink quantity that can be generated by a device having at least one ink jet print head. The invention can be employed for determining the ink supply in ink tank cassettes for postage meter machines that print with an ink jet print head and allows the maximum utilization until the ink tank cassette is replaced.
2. Description of the Prior Art
Postage meter machines have been known since the 1920's and are still being constantly perfected. The printing principle has changed from original, purely mechanical solutions with printing drums to electronic solutions with thermal transfer or ink jet printing head. The franking imprint must be capable of being read visually and by machine by the postal authorities in order to be able to verify the payment of postage.
An ink that has not been inspected by the manufacturer or not approved by the manufacturer represents a risk to the legibility of the franking imprint. At time intervals, the used ink must be replaced by new ink, or the ink cassette must be replaced. It is in the interest of the manufacturer's customers and of the postal service to use qualitatively high-grade, proper material.
Indicating an impending change of consumable via a display is disclosed; in German Published Application 195 49 376, wherein sensors are used for determining the remaining amount of an inking ribbon on inking ribbon cassette for a thermal transfer printer or to count the number of imprints with the controller of the thermal transfer printer. This solution, however, is only suited for a thermal transfer postage meter machine, such as for the model Type T1000 offered by Francotyp-Postalia AG & Co., and cannot simply be transferred to postage meter machines with ink jet printers, due to the non-linear relationship between the remaining quantity of ink and number of imprints in such machines.
German Patent 196 13 944 discloses an ink cassette with two approximately identically constructed ink reservoirs that is suitable for the JetMail® type of postage meter machine also offered by Francotyp-Postalia AG & Co. One ink reservoir serves for disposal of ink collected during priming. The other ink reservoir serves for ink supply and has an end of ink detection with two electrodes, but does not supply information about the filling level either before or after the end signal. A perforation encoding that has also been disclosed does not offer adequate protection against a utilization of an ink tank cassette that is not authorized by the manufacturer of the postage meter machine.
And end of ink detection with electrodes is known from German Patent 27 28 283. Two electrodes for a comparative measurement and a separate electrode for a conductivity measurement for signaling the end of ink are introduced into the floor of the ink reservoir. The transfer impedance between these electrodes is measured with an electronic circuit and is interpreted. The electrodes are arranged in troughs that are formed in the reservoir base. A pre-condition for the use of such an end of ink recognition is the employment of an electrically conductive ink. Such sensors for detecting the end of ink already supply the JetMail® postage meter machine with an end signal when a maximum of 200 frankings are still possible in order to avoid an incompletely printed franking imprint that has already been debited due to lack of ink. However, a cleaning with ejection (priming) and/or extraction of ink is then no longer possible. The end signal is usually emitted too late to re-order an ink tank when large quantities of mail are processed, and too early when small quantities of mail are processed.
Cassette-shaped containers with ink fluid, inking ribbon or toner are disclosed in U.S. Pat. No. 5,365,312, having an integrated circuit chip with an electronic memory for a code identifying the reservoir, for expiration data and other data, as well as with a counter in order to identify the consumption during printing by counting the individual print pulses, which correspond to the drops of ink that are printed out (ejected). The integrated circuit stores the current filling status and this can be read out and displayed by the printer controller. A reprogramming of the chip and a refilling of the container, however, are not possible. The ink cassette with the chip counts the individual drops and allows use in office printers. The high technical outlay for counting drops, however, is justified only for printing wherein one must expect extremely large differences in consumption for different print images. Due to the large differences in the nature of the print images, however, no conclusion can be made regarding the number of printings that are still possible with a remaining quantity of ink.
European Application 875 862 discloses an ink jet print head for postage meter machines that carries an integrated ink tank and a connector with many contacts and a chip for storing a head identification number and a count. The count corresponds to the number of maximally possible franking imprints, and franking can be carried out with the postage meter machine only when the head identification number is authorized and the maximum number of franking imprints has not yet been reached. This solution can be utilized for ink jet printer postage meter machines only because an essentially constant ink consumption can be expected for franking, particularly stacks of mail. Only the ink consumption is indicated. The user of a postage meter machine, however, would like to be certain that a franking imprint that has been debited can always be completely printed, i.e. even when the end of ink is near. The above solution therefore is unsuitable for ink jet printer postage meter machines. Counting the (normal) imprints cannot supply any information about the number of possible imprints with the amount of ink remaining in the ink tank because, given a low through medium number of frankings per day, the consumption of ink due to the cleaning procedure predominates, which reduces the number of possible imprints per ink tank fill. Given piezo ink jet print heads, a large part of the ink is lost in cleaning with priming and extraction and cannot be re-supplied to the head.
U.S. Pat. No. 5,856,834 discloses a device and method for monitoring the ink consumption in an ink cartridge of a postage meter machine. This device has respective microprocessors in the meter (vault), in the base and at the print head. For cleaning the ink jet print head, the base microprocessor activates a pump station and activates the print head microprocessor and an ASIC for head rinsing. The cleaning and rinsing can be undertaken with different intensities. Compared to a cleaning, a rinsing causes in ink consumption that is reduced by two through four orders or magnitude, which is taken into consideration by software in the base microprocessor. A strong rinsing, “power flush” causes an ink consumption comparable to a franking imprint with an advertizing slogan. Upon initialization of the print head, however, ten times the ink is consumed compared to an intense cleaning, “power purge”. Logically, high ink consumption would be disadvantageous when there is only a small residue of ink in the cartridge. The consumption due to cleaning and rinsing is therefore reduced when the ink consumption falls below a predetermined threshold. Since a safety margin is also embodied in the calculations, the device is able to “know” that the remaining quantity of ink is still sure to suffice for a large number of imprints. The agreement between the calculated and the actual consumption deviates more greatly at the pre-calculated end of ink than at the beginning of the calculation because all influencing factors are not able to be taken into account. If information about remaining ink quantity were determined from the consumption, then the imprecision would be greatest close to the end o
Kubatzki Ralf
Thiel Wolfgang
Francotyp-Postalia AG & Co.
Hallacher Craig
Tran Ly T
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