Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-02-27
2004-09-14
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06789869
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to printer-control apparatus and method. Particularly, this invention relates to printer-control apparatus and method that achieve PF (paper-feed) measurements to measure motor currents in accordance with the load on a motor at a constant-speed driving operation and calculate the average of the motor currents at several occasions in addition to at the time of printer power-on, for precise paper-feed control even at a small paper-feeding amount in one paper-feeding action. The present invention also relates to a storage medium storing a program for executing the printer-control method.
2. Related Background Art
PF (paper-feed) measurements are known for printer-control apparatus and methods in which motor currents are measured in accordance with the load on a motor at a constant-speed driving operation and the average of the motor currents is calculated at the time of printer power-on, for precise paper-feed control even at a small paper-feeding amount in one paper-feeding action.
For regular-type printers, an acceleration control under an open-loop control is performed on starting of motor for paper feeding and thereafter a constant-speed control is performed under a PID control switched from the open-loop control when the motor speed approaches a speed within the constant-speed control range.
Under the PID control, the integrals of motor currents I are accumulated and the magnitude of load on a motor is always measured for motor-current control in accordance with the load magnitude with which the motor currents I have a proportional relation. Variation in motor current I due to disturbances, etc., under the PID control will not affect the precise control because of motor-current adjustments using accumulated integrals of motor currents I.
On the contrary, under the open-loop control, accumulation of the integrals of motor currents I will not be performed, and hence motor-current adjustments cannot be applied in case of variation in motor current I due to disturbances, etc. Motor-current errors will thus often occur during the open-loop control just after the motor start-up, causing imprecise control.
The open-loop control is switched to the PID control before the completion of paper-feed operation for a large paper-feeding amount in one paper-feeding action. A precise paper-positioning is thus relatively easily achieved with motor-current adjustments using accumulated integrals of motor currents I in case of errors in motor current.
Contrary to this, the open-loop control almost dominates the paper-feed operation for a small paper-feeding amount in one paper-feeding action. A precise paper-positioning will not be achieved due to short time and distance for this paper-feed operation and the motor-current adjustments using accumulated integrals of motor currents I being impossible in case of errors in motor current.
Therefore, the known PF measurements are performed whenever a printer is turned on such that motor currents are measured beforehand in accordance with the load on a motor at a constant-speed PF-motor driving operation and the average of the motor currents is calculated using the integrals of motor currents for indirect measurements of the load on paper feeding.
In detail, the known PF measurements are performed such that motor currents are measured for a paper-feeding operation carried out when a printer is turned on and the integrals of motor currents are accumulated in calculation of average motor current for indirect measurements of the load on a paper-feeding mechanism. Measurements of the load on a paper-feeding mechanism may not always require printing papers set therein. The calculated average motor current is stored in a memory installed in a printer. Pre-stored in the memory is an offset value of a motor current converted from the load on the paper-feeding mechanism that is a printing paper set therein. The calculated average motor current and the offset value may be stored in different memories.
The average motor current obtained through the PF measurements will be applied to a subsequent paper-feed operation at a small paper-feed amount in one paper-feeding action, with no PID control. Average motor currents obtained through the PF measurements carried out with a printing paper set in the paper-feeding mechanism are available with no offset values. On the contrary, average motor currents obtained through the PF measurements carried out with no printing papers set in the paper-feed mechanism require offset values. Accordingly, a precise paper-positioning with an accurate paper-feeding control is achieved even at a small paper-feeding amount in one paper-feeding action.
The known PF measurements will be performed whenever a printer is turned on due to variation in load on a paper-feeding mechanism caused by several factors. For example, the load on a paper-feeding mechanism of each printer when shipped from factories will relatively be large but small when the paper-feeding mechanism works smoothly after several uses. In addition, a low environmental temperature will cause a large load on driving whereas a high environmental temperature will cause a small load on driving. Other factors for variation in load on driving are, for example, the amount of lubricant and its condition used for a paper-feeding mechanism and abrasion conditions for rotary shafts incorporated in the mechanism. The maximum degree of variation in load on driving could reach two times the minimum degree.
Therefore, the known PF measurements are performed whenever a printer is turned on, for a precise paper-feed control using the most suitable average motor current calculated per measurement.
The known PF measurements, however, have the following drawbacks due to the fact that the measurements are carried out only when a printer is turned on.
Printers have been used widely and many of them are installed in offices and convenience stores, etc., as network printers that operate for 24 hours or a long period of time.
Application of the known PF measurements available only at the time of power on to these printers thus cause long use of an average motor-current value once calculated to paper-feed control.
The load on a paper-feeding mechanism and the corresponding motor current will, however, vary due to several factors as discussed. This variation causes a large difference between an average motor current to be applied to a paper-feeding mechanism and a motor current in accordance with an actual load on driving, thus lowering accuracy of paper-feed control.
SUMMARY OF THE INVENTION
A purpose of the present invention is to provide printer-control apparatus and method that achieve PF measurements at the time of printer power-on and also other occasions for precise control to a paper-feed motor for driving a paper-feeding mechanism of a printer to be used in variety of environments even at a small paper-feeding amount in one paper-feeding action.
According to the printer-control apparatus of the present invention, there is provided with a printer-control apparatus comprising a PF-measurement generator/executor for generating and executing an operation for PF-measurements to measure a motor current in accordance with load on paper feeding while a paper-feed motor is running at a constant-speed driving in accordance with detection of specific statuses in addition to printer power-on.
According to the printer-control method of the present invention, there is provided with a printer-control method comprising the step of generating and executing an operation for PF-measurements to measure a motor current in accordance with load on paper feeding while a paper-feed motor is running at a constant-speed driving in accordance with detection of specific statuses in addition to printer power-on.
In the above configuration of the printer-control apparatus and method of the present invention, the PF-measurements may include calculation of an average motor-current value for the paper-feed motor.
The present invention achieves
Gordon Raquel Yvette
Sughrue & Mion, PLLC
LandOfFree
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