Facsimile and static presentation processing – Static presentation processing – Data corruption – power interruption – or print prevention
Reexamination Certificate
1999-07-29
2004-02-17
Grant, II, Jerome (Department: 2722)
Facsimile and static presentation processing
Static presentation processing
Data corruption, power interruption, or print prevention
C358S001130
Reexamination Certificate
active
06693717
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing apparatus (a printer), a printer initialization method, and a computer-readable data storage medium recording a program for controlling a printer. More particularly, the present invention relates to an initialization process that is accomplished when the printer is turned on, and an initialization process that is accomplished in response to a printer reset request from a host device.
2. Description of the Related Art
Printing apparatuses (referred to below as “printers”) typically perform a predetermined printer initialization process when the printer power is turned on, when the printer begins operation, and also when a reset request is received by the printer from a host computer or from the host device in a point-of-sale (POS) terminal with which the printer is used.
Systems in which the power supplies of the printer and host device are linked such that the printer and host device power turns on substantially simultaneously are widely used, for example, in POS systems. When printer power turns on in conjunction with host power in such systems, the host device BIOS (basic input output system) typically sends a reset request to the printer. Then, the operating system (OS) that runs on the host device sends a reset request to the printer, and then the application program that runs on the OS sends another reset request to the printer. This means that when a conventional printer that executes a predetermined printer initialization process when the power is turned on is used in this type of system, multiple reset requests are asserted by the host to the printer before the printer can complete the predetermined initialization process caused by the power-on reset of the printer.
When the printer receives a reset request from the host device, the printer CPU controlling general printer operation is reset. This causes CPU operation to stop and drives all I/O ports to a high impedance state, thus interrupting any initialization process that was started when printer power was turned on and is still in progress when the reset request from the host device is received.
Problems Relating to Initialization Process Interruption
Printer initialization typically includes the following tasks:
a) initializing such control circuits as the CPU controlling printer operation, and RAM used as a communications buffer for communicating with the host device;
b) excitement of the stepping motor phase for matching the operating phase of, for example, the stepping motor for driving the print head in the line direction;
c) a cleaning process for cleaning the printing elements of the print head to assure print quality; and
d) moving the print head to a reference position in the line direction.
Some of these initialization processes require more time than others. For example, phase excitement of the stepping motors requires relatively little time, while print head positioning and print head cleaning require relatively more time.
The cleaning process required to clean an ink jet print head includes a suction step in which a vacuum pump is used to suction ink from the print head, and thus consumes a quantity of ink. It also takes time for suction to actually begin once the vacuum pump starts operating, and interrupting the cleaning process is therefore also a wasteful use of time. Yet further, interrupting this cleaning process once ink suction has begun means the amount of ink that has been drawn so far is unknown. The suction step can therefore not be resumed, and must be repeated from the beginning. This obviously consumes more ink than does completing the suction step uninterrupted.
Problems Relating to Reseating the Initialization Process
When reset requests are repeatedly issued, the initialization process is performed in response to each reset request. This causes the following problems.
A stepping motor must be driven to position the print head to the reference position. The gear set, including the gears connected to the stepping motor, is therefore driven to move the print head, and repeating this positioning process in response to redundant reset requests needlessly advances wear on the associated mechanical parts.
It is also not normally possible to know where the print head is positioned when this operation starts. It is therefore necessary to move the print head to a known position against a stopper, and repeatedly driving the print head against this stopper can result in damage to the print head.
Repeatedly performing the cleaning process described above also consumes a needlessly large amount of ink, and thus makes it necessary to replace the ink cartridge sooner.
Repeatedly performing the initialization process is illustrated in
FIGS. 1A and 1B
.
FIG. 1A
shows the sequence of processes performed when printer power is turned on independently of the host device, such as when printer power is turned on after the host is operating.
The first step of this initialization process after the power is turned on is stepping motor phase excitement
101
, followed by print head positioning
102
, and then print head cleaning
103
. The printer then proceeds to normal operation
104
in which the printer waits for a print command and data from the host device.
FIG. 1B
shows a sequence of processes typically performed when a conventional printer is connected to a host device such that power supply to both the printer and host device begins substantially simultaneously with the resultant reset requests from the host device as described above. In
FIG. 1B
, a reset signal is asserted by the host device to the printer at the rising edge following a drop in the reset signal output
105
. As a result, low level pulses
106
,
107
, and
108
in the reset signal output
105
indicate reset signals received by the printer.
After the printer completes stepping motor phase excitement
101
, and print head positioning
102
is in progress, it receives a reset signal
106
from the host device BIOS. Print head positioning
102
is therefore interrupted, and stepping motor phase excitement
101
and print head positioning
102
are repeated from the beginning.
Next, stepping motor phase excitement
101
and print head positioning
102
are completed, and a reset signal
107
is received from the host device OS while print head cleaning
103
is in progress. Print head cleaning
103
is therefore interrupted, and stepping motor phase excitement
101
, print head positioning
102
, and print head cleaning
103
are repeated from the beginning.
Next, reset signal
108
is received from the host device application program while print head cleaning
103
is in progress. Print head cleaning
103
is therefore again interrupted, and stepping motor phase excitement
101
, print head positioning
102
, and print head cleaning
103
are again repeated from the beginning.
OBJECTS OF THE INVENTION
In consideration of the above-described problems, an object of the present invention is to prevent wasting of consumables in the printing apparatus, and to prevent a loss of mechanical durability that results when a printer initialization process, performed when printer power is turned on, is interrupted by a printer reset signal asserted by a host device to the printer immediately after host power turns on.
SUMMARY OF THE INVENTION
To achieve the above object, a printing apparatus according to the present invention for printing on a printing medium (e.g. paper) using a print head according to data received from a host device comprises: a power on initialization controller for initializing the printing apparatus when the printing apparatus power is turned on; and a first timer for measuring a first predetermined time after the printing apparatus starts operating. The power on initialization controller performs a first initialization process before the first timer finishes measuring the first predetermined time, and performs a second initialization process differing from the first initialization process after the first timer finishes measur
Kawase Yuji
Nishioka Atsushi
Teradaira Mitsuaki
Grant II Jerome
Seiko Epson Corporation
Watson Mark P.
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