Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-07-15
2001-07-24
Barlow, Jr., John E (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S039000, C347S023000
Reexamination Certificate
active
06264304
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of Invention
This invention related to an ink jet recording apparatus and method, and more particularly to an ink jet recording apparatus with a carriage lock mechanism and a method for controlling the same.
2. Related Art
Typically an ink jet recording apparatus has a recording head which moves along a sheet of recording paper by means of a carriage, ejecting ink drops thus printing on the surface of the recording paper. Often times during printing, the carriage will be put into a waiting condition and be placed in a home position away from the printing area. While the carriage carrying the recording head is under a printing waiting condition, it moves to a predetermined home position which is located off the recording area and waits for a printing command at the home position.
Although the carriage driving mechanism applies a brake force to keep the carriage in its home position, exterior vibrations may move the carriage toward the recording area while the carriage is waiting in the home position. Furthermore, when electric power is turned off, the carriage may be able to freely move, and there is a risk that the carriage may move toward the recording area from the home position.
In order to prevent unwanted movement of the carriage, an ink jet recording apparatus is often provided with carriage lock mechanisms for mechanically fixing the carriage at the relevant home position. (For example, U.S. Pat. No. 4,695,851 and U.S. Pat. No. 4,739,847) These conventional carriage locking mechanisms are constructed in such a way that each time the carriage returns to the home position the carriage is locked. Since the driving frequency of the carriage lock mechanism is high, there are associated problems with keeping the carriage locked. One such problem is that the components of the carriage lock mechanism rapidly deteriorate.
Another problem exists when printing should be restarted immediately after a previous printing is finished, requiring the carriage lock to be disengaged. The result is decreased responsiveness of the carriage when restarting the printing.
It is desirable to have an ink jet recording apparatus which can prevent deterioration of the components caused by the carriage lock and decreased responsiveness when the printing restarts, by avoiding unnecessary carriage lock actions.
SUMMARY OF INVENTION
In general, in one aspect, the invention features an ink jet recording apparatus which includes a recording head for ejecting ink liquid drops, a carriage for carrying the recording head and adapted to translate between a recording area and a home position, a carriage lock mechanism for locking the carriage at the home position, a carriage controller for translating the carriage to the home position, a timer for measuring a waiting time during which the carriage translated by the carriage drive control part is at the home position, and a lock controller which allows the carriage lock mechanism and the carriage to be into a locked condition when the waiting time measured by the timer has reached or exceeded a predetermined time.
The carriage lock will not be effected even if the carriage has returned to the home position, unless the carriage is waiting at the home position for more time than a predetermined period. If a command for restarting a printing is issued during the time, the carriage can be immediately moved to the recording area. If the carriage lock is set simultaneously when the carriage has returned to the home position, the driving frequency of the carriage lock mechanism is reduced, and the deterioration of the components of the carriage lock mechanism can be reduced. In addition, since frequency of disengaging the carriage lock mechanism is low, the responsiveness at the restart of the printing will be improved.
Implementations may include a maintenance unit for restoring the relevant recording head by sucking ink from ink nozzles in the recording head and disposing it to the exterior, and head restoration requesting means for issuing a head restoration request by the maintenance unit. It is preferable that the carriage lock is instantly engaged when the head restoration request is issued, regardless of the time during which the carriage is waiting at the home position, to prevent the ink from leaking out by movement of the carriage during suction of the ink.
Since the printing action will not start immediately after the electric source of the apparatus is switched on, the carriage can be locked by actuating the carriage lock mechanism, regardless of the above-described waiting time.
Implementations may also include a detector for detecting that the carriage has moved to the home position so as to start a measurement of the waiting time by means of the timer, by referring to results of detection by the detector as a trigger.
In another aspect, the invention features a method for controlling the ink jet recording apparatus including translating a carriage from a home position to a recording area according to a printing command, translating said carriage to said home position after a printing is finished, measuring a waiting time during which said carriage stays at said home position, after translating said carriage to said home position after a printing is finished is conducted, actuating a carriage lock mechanism when said waiting time has exceeded a preset time, to switch said carriage into a locked condition.
Implementations may include interrupting measurement of said waiting time, on receiving the printing command again within said preset time, in the previous step of actuating a carriage lock mechanism when said waiting time has exceeded a preset time, to switch said carriage into a locked condition, and translating said carriage from said home position to said recording area.
Implementations may also include actuating said carriage lock mechanism regardless of said waiting time on receiving a head restoration request from an ink suction mechanism, thereby to switch said carriage into the locked condition.
The invention may provide one or more of the following advantages.
The carriage lock is not conducted until the preset waiting time expires since the carriage has returned to the home position, and the printing can be instantly restarted on receiving the command for restarting the printing within the period. Therefore, responsiveness for restarting the printing is better than with the conventional apparatus for which disengagement of the carriage lock must be awaited. Further, comparing with the conventional apparatus in which the carriage lock is conducted each time the carriage returns to the home position HP, the frequency of the carriage lock is low, and accordingly the deterioration of the components pertaining to the carriage lock can be restrained.
In addition, the carriage lock is conducted immediately after the electric power is applied, regardless of the waiting time, and so, the ink will not leak out to the exterior even if vibrations occur due to setting of a roll paper or a cartridge immediately after the application of the power.
Moreover, when the head restoration request is issued, the carriage lock is instantly conducted, thus enabling the ink suction operation to be conducted always in the locked condition. Therefore, this can avoid such disadvantages as the ink leaks out to the exterior as the carriage slides during the ink suction process.
Further details of an ink jet recording device and method suitable for use in further embodiments are disclosed in US application entitled “Ink Jet Recording Apparatus”, assigned to the same assignee, Seiko-Epson Corporation, filed on the same date, and with priority based on Japanese Patent Application Hei 10-201009, filed Jul. 15, 1998.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
REFERENCES:
patent: 4177471 (1979-12-01), Mitchell
patent: 4551736 (1985-11-01), Suzuki et
Iwaya Satoshi
Kobayashi Naoki
Nishioka Atsushi
Barlow Jr. John E
Mouttet Blaise
Nixon & Vanderhye P.C.
Seiko Epson Corporation
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