Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1996-10-25
2001-06-12
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06244680
ABSTRACT:
The present invention concerns, in general terms, a device and a method for detecting or measuring a quantity of product remaining in a reserve of product designed to be subjected to a series of driving movements.
More particularly, the present invention relates to a device and a method for detecting or measuring a quantity of product remaining in a reserve of consumable product arranged in a cartridge forming part of a printing device. It also concerns a printing device, a computer, a photocopier and a facsimile machine incorporating such a device.
It is known that the applicant has, for several years, used a so-called “bubble jet” method of printing. In global terms, this method consists of projecting liquid ink drops onto the paper. The liquid ink is contained in a reserve arranged in a cartridge associated with a printing head. The printing head includes a plurality of aligned nozzles, the function of each nozzle being to eject ink designed to product a dot on the sheet. During the printing process, the cartridge and printing head sweep over the width of the sheet, whilst the latter advances step by step over its length. To this end, the cartridge and the printing head are driven in their translational movement by a driving device including in this case an electric motor controlled by control means. These control means are, in general terms, adapted to transmit electrical signals to the motor to cause the assembly to move, drive it at the required translational speed and stop it. This technology is the object of several patents, amongst them the document EP-A-0 588 616 A1, whose description is incorporated herein.
In general terms, the problem underlying the present invention is that of knowing the quantity of consumable product in a reserve subjected to a movement. A particular application of the invention concerns the measurement, in a facsimile machine, of the quantity of ink still available. This is because it is important for the user of a facsimile machine to know in time that the reserve is about to be emptied.
It is therefore desirable to have available a means of measuring the quantity of this consumable product, referred to below for the sake of clarity as “ink”, regardless of whether it is in solid, liquid, gaseous or powder (toner) form.
In expensive devices, an ink level detector is incorporated into the cartridge, but this solution cannot be adapted to low-priced devices owing to the fact that the cost of each detector is itself prohibitive for this application.
The objective of the present invention is consequently to enable a quantity of product remaining in a reserve arranged in a cartridge to be detected or measured, without using detectors incorporated into the latter.
The inventors also set themselves the objective of performing this detection or measurement without modifying the mechanical structure of the cartridge and/or printing device as marketed at the present time or, at the very least, modifying the printing device as little as possible.
The present invention achieves these objectives since it relates first of all to a device for detecting the quantity of a product remaining in a reservoir subjected, in the course of its utilization, to a driving movement by a drive device controlled by control means adapted to send to the drive device reference signals representing required accelerations or decelerations and/or speed, the drive device being able to confer on the reservoir, for a predetermined quantity of product in the reservoir, a predetermined maximum acceleration or deceleration and/or speed, characterized in that it includes testing means which, on the one hand, act on the control means in order for the latter to send test reference signals representing an acceleration or deceleration and/or a speed greater respectively than the said predetermined maximum acceleration or deceleration and/or speed and, on the other hand, detect at least one physical effect induced by the said test signals.
The invention also concerns a method for the detection of a quantity of product remaining in a reservoir subjected, in the course of its utilization, to a driving movement by a drive device controlled by control means adapted to produce for the drive device reference signals representing required accelerations or decelerations and/or speed, the drive device being able to confer on the reservoir, for a predetermined quantity of product in the reservoir, a predetermined maximum acceleration or deceleration and/or speed, a method characterized in that it comprises a testing phase in the course of which:
the control means are acted upon in order for the latter to send a testing signal representing an acceleration or deceleration and/or a speed greater respectively than the said predetermined maximum acceleration or deceleration and/or speed and,
at least one physical effect induced by the said test reference signal is detected.
In a preferred application, the reserve of product is a reserve of liquid ink forming part of an ink cartridge. However, the scope of the invention is not limited to liquid inks, but encompasses the detection or the measurement of a remaining quantity of product, whether it be in solid, liquid, gaseous or powder form, in a reserve of the said product. In particular, printers using solid inks, whether in the form of powder, also called “toner”, or in the form of a stick, can advantageously incorporate the device which is the object of the present invention. By virtue of these arrangements, the device and method achieve the objectives assigned to them above.
To each quantity of product remaining in the reserve, there corresponds an acceleration, a deceleration and/or a maximum speed which the driving device is able to confer on the reserve.
During the testing phase, by causing the transmission of reference signals representing performances beyond normal operating conditions of the drive device, here, in the example illustrated in the figures, an electric motor, several physical effects are generated. These physical effects can, for example, be a rise in the temperature and/or an abnormal movement of the liquid reserve, that is to say they do not correspond to the theoretical movement relative to the reference value. By detecting or measuring at least one of these physical effects, the invention makes it possible to detect that a threshold relating to total mass in movement, and consequently to the quantity of product remaining in the reserve, has been passed.
The value of the physical effect relating to each signal can easily have been determined previously for a predetermined quantity of remaining product in the product reserve and be stored in the memory of movement-control logic circuits, with the associated measurement value.
Consequently, the present invention requires, in order to be implemented, only a modification to the control program of the motor to implement the steps of the method defined above and, optionally, a detector detecting the said physical effect. It will thus be observed that the invention, as defined succinctly above, enables its objectives to be attained whilst avoiding the need to carry out substantial modifications of a mechanical nature, whether to the cartridge or to the head driving device.
The present invention thus also makes it possible, through the regular implementation of testing or measurement phases (notably outside the phases of reception of documents in the case of a facsimile machine or between the phases of printing of each page), to determine whether or not the minimum quantity of ink is reached in the cartridge reserve. The user can then be alerted when this minimum quantity is reached and proceed with the replacement of the cartridge.
According to a preferred aspect of the present invention, the said physical effect detected is a movement, and the testing means are adapted to detect any movement of the said reservoir following the sending of the said test signals.
This aspect of the invention is particularly advantageous in that the physical effect, movement in this case, can be detected or m
Coudray Pascal
Dodge Alexandre
Froger Marie-Helene
Truffaut Christophe
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Le N.
Nghiem Michael
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