Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-12-17
2004-08-17
Pham, Hai (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S084000, C347S085000
Reexamination Certificate
active
06776467
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of controlling an ink jet recording apparatus that supplies ink from main tanks storing ink to ink jet heads through sub-tanks.
2. Prior Art
Conventionally, in a relatively large-sized ink jet recording apparatus, such as an ink jet printer, a main tank for storing ink and an ink jet head are connected to each other through an ink tube such that ink is supplied from the main tank to the ink jet head by suction action caused by operation of the ink jet head.
The ink jet recording apparatus of this kind suffers from a problem that it is difficult to maintain stable ejecting performance of the ink jet head due to changes in water head pressure since the ink level in the ink tank depends on the amount of ink stored in the ink tank. Further, to prevent ink from dripping from the ink jet head, it is necessary to arrange the ink jet head at a location slightly higher than the ink tank. However, it is not always possible to properly arrange a large-sized ink tank within a limited space in the ink jet recording apparatus.
To overcome the above problems, so as to increase the degree of freedom of arrangement of the ink tank, it is contemplated that a sub tank is interposed between the ink tank (main tank) and the ink jet head to secure the above water head pressure by using the sub tank. Further, it is preferred that the sub-tank is a bag-like one formed by a vapor deposited film or the like so as to prevent air from being mixed in the ink.
However, in the case of the ink jet recording apparatus which uses the sub-tank as described above, it is preferable to employ a pressure tank since pressure variation is undesirable for ink supply from the main tank to the sub-tank. In the case of the use of the pressure tank, when it is necessary to make the pressure tank open to the atmosphere e.g. because of abnormal stoppage of the apparatus or for replacement of the main tank, safety must be ensured. Further, since ink ejected from the ink jet head is supplied from the sub-tank, it is necessary to realize stable supply of ink from the main tank to the sub-tank.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method of controlling an ink jet recording apparatus, which ensures safety in replacing main tanks or the like and at the same time enables stable supply of ink from main tanks to sub-tanks.
To attain the above object, according to a first aspect of the invention, there is provided a method of controlling an ink jet recording apparatus including a main tank having an information storage section for storing an ink amount and ink attributes as ink information and replaceably received in a pressure tank, a sub-tank communicating with an ink jet head and storing ink sent from the main tank by pressure in the pressure tank, a tank-accommodating block for accommodating the main tank together with the pressure tank, and a control section capable of storing the ink information to be stored in the main tank. The ink jet recording apparatus supplies the ink in the main tank to the sub-tank by opening and closing a valve arranged on a upstream side of the sub-tank in response to a signal indicative of an ink fill-up/shortage condition of the sub-tank. The method comprise the step of stopping operation of a pressure source for pressurizing the pressure tank and at the same time making an inside of the pressure tank open to the atmosphere as well as writing an item of the ink information concerning the ink amount of the main tank stored in the control section into the information storage section of the main tank, in response to a signal indicative of opening of a door of the tank-accommodating block during operation of the apparatus.
According to this method, when the door of the tank-accommodating block is opened in response to the signal indicative of opening of the door, the operation of the pressure source for pressurizing the pressure tank is stopped, and the inside of the pressure tank is made open to the atmosphere. This enables makes it possible to instantly reduce pressure in the pressure tank. More specifically, if an operator (user) erroneously opens the door without carrying out operation of making the pressure tank open to the atmosphere, the pressure in the pressure tank can be reduced before it is made open to the atmosphere. This makes it possible to reliably prevent the user from erroneously opening the pressure tank under high pressure. Further, when the door is opened, ink information concerning the ink amount of the main tank stored in the control section is written in the information storage section of the main tank, so that it is possible to prevent any missing of the ink information from occurring, and at the same time confirm the identity of the main tank when the door is closed again.
Preferably, the method further comprises the step of closing the valve arranged on the upstream side of the sub-tank in response to the signal indicative of opening of the door of the tank-accommodating block during operation of the apparatus.
According to this preferred embodiment, even if ink is being supplied through an ink supply passage when the door of the tank-accommodating block is opened, the ink supply passage is blocked by closing the valve. Therefore, it is possible to positively stop the ink supply. Further, since the ink supply is carried out after the ink information is stored in the information storage section of the main tank, it is possible to prevent generation of an error between the information stored in the information storage section of the main tank and the information stored in the control section.
Preferably, the method further comprises the step of stopping cleaning operation of sucking ink from the ink jet head in response to the signal indicative of opening of the door of the tank-accommodating block during operation of the apparatus.
According to this preferred embodiment, even if the cleaning operation is being carried out by sucking ink from the ink jet head, when the door of the tank-accommodating block is opened, and an ink supply passage from the sub-tank to the ink jet head is not placed in a negative pressure state by the cleaning operation, which contributes to prevention of reverse flow of ink caused by the ink supply passage being in the negative pressure state upon termination of the cleaning operation. This makes it possible to prevent the ink jet head from being contaminated by ink which has once flown out of the ink jet head by suction. Further, although there is a case in which ink is replenished during cleaning operation, it is possible to prevent an error from being produced between the ink information stored in the information storage section of the main tank when the door is opened and the ink information stored in the control section, by inhibiting the cleaning operation when the door is opened.
Further, when the ink jet head includes a plurality of nozzle arrays for different ink colors, it is possible to prevent reverse flow of ink caused by cleaning operation continued with the door of the tank-accommodating block open, thereby effectively preventing the inside of the ink jet head from being contaminated by a mixture of different colors of inks.
Preferably, the method further comprises the steps of starting operation of the pressure source for pressurizing the pressure tank in response to a signal indicative of closing of the door of the tank-accommodating block during operation of the apparatus, when an item of the ink information concerning the ink attributes stored in the information storage section of the main tank and an item of the ink information concerning the ink attributes read out from the control section agree with each other, and at the same time when ink end information indicative of an ink-used-up condition is not contained in the item of the ink information concerning the ink amount stored in the information storage section of the main tank, and executing error notification in response to the signal indicative of closin
Otsuka Nobutoshi
Yamazaki Atsushi
Hogan & Hartson LLP
Nguyen Lam S
Pham Hai
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