Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1999-05-06
2003-02-11
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S019000
Reexamination Certificate
active
06517175
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technique of causing ink droplets to be ejected on a printing medium, so as to print an image. More specifically the present invention pertains to a technique of accurately monitoring a residual quantity of ink remaining in an ink reservoir that stores the ink therein.
2. Description of the Related Art
Printers that cause ink droplets to be ejected on a printing medium to print an image are widely used as an output device of various images output from a computer or the like. Such a printer uses the ink stored in an ink reservoir to eject ink droplets, and thereby can not print an image after the ink in the ink reservoir is used up.
Some techniques have accordingly been developed to monitor the residual quantity of ink in the ink reservoir. One of such techniques installs a sensor in the ink reservoir to monitor the residual quantity of ink. This technique with the sensor enables the residual quantity of ink to be monitored directly. Another known technique multiplies the number of ink droplets ejected by a weight of a single ink droplet measured in advance, so as to calculate the amount of ink consumption, and estimates the residual quantity of ink in the ink reservoir from the calculated amount of ink consumption. Since the printer ejects ink droplets under the control of the computer, it is easy to count the total number of ink droplets ejected with the control computer. This technique enables the residual quantity of ink in the ink reservoir to be monitored without any specific sensor.
When this known technique is applied to monitor the residual quantity of ink, there may be a significant difference between the actual remaining quantity of ink and the calculated remaining quantity of ink. As is known by those skilled in the art, the size of an ink droplet ejected from a nozzle depends upon the viscosity of the ink. One proposed technique takes into account a change of the viscosity according to the temperature of the ink, in order to improve the accuracy of calculating the residual quantity of ink. This proposed technique can not, however, attain the sufficient accuracy.
SUMMARY OF THE INVENTION
The object of the present invention is thus to precisely estimate an amount of ink consumption and thereby monitor a residual quantity of ink remaining in an ink reservoir with high accuracy.
At least part of the above and the other related objects is attained by a printer having an ink jet head that ejects ink droplets and an ink reservoir that has a predetermined capacity to store ink, wherein the ink jet head ejects ink droplets to create ink dots on a printing medium and thereby print an image on the printing medium. The printer includes: a supply condition detection unit that detects an ink supply condition, where an ink droplet ejected from one nozzle affects a supply of ink to another nozzle due to the structure of the ink jet head; an ink ejecting number counter than counts an ink ejecting number ejected by the ink jet head; and a residual ink quantity monitor that monitors a residual quantity of ink remaining in the ink reservoir by taking into account the ink supply condition detected by the supply condition detection unit, based on the ink ejected number counted by the ink ejected number counter and the predetermined capacity of the ink reservoir.
The present invention also provides a method of monitoring a residual quantity of ink, which corresponds to the printer of the present invention discussed above. Namely the present invention is directed to a method of monitoring a residual quantity of ink remaining in an ink reservoir, wherein the method is applied for a printer having an ink jet head that ejects ink droplets and the ink reservoir that has a predetermined capacity to store ink, and the ink jet head ejects ink droplets to create ink dots on a printing medium and thereby print an image on the printing medium. The method includes the steps of: (a) detecting an ink supply condition, where an ink droplet ejected from one nozzle affects a supply of ink to another nozzle due to the structure of the ink jet head; (b) counting an ink ejecting number ejected by the ink jet head; and (c) monitoring a residual quantity of ink remaining in the ink reservoir by taking into account the ink supply condition detected in the step (a), based on the ink ejected number counted in the step (b) and the predetermined capacity of the ink reservoir.
The printer or the corresponding method of the present invention detects the ink supply condition relating to the supply of ink and counts the number of ink droplets ejected by the ink jet head. The structure takes into account the detected ink supply condition and monitors the residual quantity of ink in the ink reservoir based on the count of the ink ejecting number and the predetermined capacity of the ink reservoir. The amount of ink ejected from the ink jet head depends upon the ink supply condition. This arrangement of the present invention monitors the residual quantity of ink while taking into account the ink supply condition, thereby enabling the residual quantity of ink remaining in the ink reservoir to be monitored with high accuracy.
In the printer and the corresponding method of the present invention, the weight of a single ink droplet measured in a specified state of the ink supply condition may be stored in advance as a unit amount of ink. In the process of printing an image, the procedure first detects the ink supply condition relating to the supply of ink and counts an ink ejecting number within a preset time period. The procedure then multiplies the count of the ink ejecting number by the measured weight of a single ink droplet while taking into account the detected ink supply condition, and determines the ejecting amount of ink within the preset time period. The ink ejecting number may be a number of ink droplets actually ejected by the ink jet head or any suitable variable that is readily counted and is convertible to the number of ink droplets. The procedure subsequently accumulates the ejecting amount of ink thus determined to give a cumulative amount of ink ejection and monitors the residual quantity of ink remaining in the ink reservoir based on the cumulative amount of ink ejection and the predetermined capacity of the ink reservoir. The arrangement of taking into account the ink supply condition enables the precise calculation of the ejecting amount of ink and thereby enables the residual quantity of ink remaining in the ink reservoir to be monitored with high accuracy.
In accordance with one preferable modification, the printer stores the volume of a single ink droplet as the unit amount of ink, instead of the weight of a single ink droplet. In the process of printing an image, the procedure detects the ink supply condition and counts the ink ejecting number within the preset time period. The procedure then calculates the ejecting amount of ink within the preset time period from the stored volume of a single ink droplet and the count of the ink ejecting number while taking into account the detected ink supply condition, and accumulates the ejecting amount of ink thus determined to monitor the residual quantity of ink remaining in the ink reservoir. This structure calculates the ejecting amount of ink while taking into account the ink supply condition. This enables the ejecting amount of ink to be calculated precisely and thereby improves the accuracy of monitoring the residual quantity of ink.
The following technique is preferably applicable to take into account the effect of the ink supply condition in the process of calculating the ejecting amount of ink within the preset time period. The technique stores in advance adequate correction coefficients corresponding to a variety of ink supply conditions. The procedure multiplies the weight of a single ink droplet, the count of the ink ejecting number within the preset time period, and the correction coefficient corresponding to the detected ink supply condition. This arrangement
Kanaya Munehide
Yonekubo Shuji
Barlow John
Brooke Michael S
LandOfFree
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