Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-11-24
2001-09-11
Tran, Huan (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S023000, C347S032000, C347S104000, C347S106000
Reexamination Certificate
active
06286931
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to ink jet recording apparatuses in general, and more particularly to an ink jet recording apparatus featuring a mechanism that causes a single drive motor to perform both a recording head maintaining operation and a recording sheet feeding/discharging operation.
BACKGROUND OF THE INVENTION
An ink jet recording apparatus requires a drive system for performing a recording sheet feeding/discharging operation and a recording head maintaining operation, in addition to carriage travelling operation. Conventionally, printers have a switching mechanism that enables a single drive motor to perform these sheet feeding/discharging and recording head maintaining operations in order to miniaturize and reduce the price of the apparatus.
The switching mechanism switches a drive force of a sheet forward motor between a pump drive system and a sheet feed/discharge drive system when the carriage has moved from a home position to a printing region and when the carriage has moved from the printing region to the home position. This switching feature involves selectively meshing a switching gear with gears of the sheet feed/discharge system and with gears of the pump system such a switching feature is generally thought to be acceptable, however, it is not without shortcomings. In particular, the gears cannot be meshed with each other smoothly because they are not phased together. As a result, sheet feed timings may be disturbed. Furthermore, conventional apparatuses require a disadvantageously large number of components.
Further, an ink jet recording apparatus includes a cleaning mechanism be disposed in a region outside a data recording region to maintain a recording head in a satisfactory condition at all times. As a result, the width of the apparatus is necessarily increased. The increased width is especially disadvantageous in an ink jet recording apparatus dedicated to color printing. For example, same apparatuses use yellow, magenta, cyan, and black inks and further use two kinds of inks, dark and light, for each of these colors. Consequently, the recording head that jets these inks in the form of ink droplets is necessarily increased. Also, capping unit and the cleaning mechanism whose size depends on the size of the recording head are necessarily large-sized. As a result, if the carriage, the recording head, the capping unit, and the cleaning mechanism are disposed within the housing at a high density in an effort to miniaturize the recording apparatus, the printing margins disadvantageously are reduced. For example, the cleaning mechanism may inadvertently move into the carriage travelling path such that during the recording operation, the cleaning mechanism contacts the carriage, thereby disturbing the recording operation.
Further, the number of nozzle openings of the black recording head for jetting black ink and of the color recording head for jetting three kinds of color inks is increased in order to accommodate the needs for high-density and high-speed printing. In association therewith, if the sizes of the recording heads in the sheet forward direction and in the sheet width direction are increased, the sizes of the caps for sealing the respective recording heads are necessarily increased. As a result, the sealability of the caps is impaired due to displacements or the like at the time the caps come into contact with the recording heads.
SUMMARY OF THE INVENTION
The invention is applied to an ink jet recording apparatus wherein a single drive means capable of switching rotational directions between a forward direction and a reverse direction is coupled to recording sheet feed/discharge means and to ink sucking means so that a recording sheet discharging operation and an ink sucking operation are performed while the drive means is rotating in the reverse direction, the drive means being coupled to the ink sucking means through coupling means for causing a time lag at the time of switching the rotational directions.
Further, the invention is applied to an ink jet recording apparatus having a capping unit, the capping unit including: a slider being biased by a recording head or a carriage carrying the recording head and thereby following a movement of the carriage over a base table while vertically moving in coincidence with the movement of the carriage; a holder being held by the slider while urged toward the recording head by springs on both sides outside a sealing region of the recording head; and a cap for sealing a nozzle surface of the recording head, the cap being accommodated in the holder and being made of an elastic member.
Therefore, a first object of the invention is to provide an ink jet recording apparatus that can not only implement accurate sheet feeding/discharging operation without being affected by load fluctuations accompanied by the ink sucking operation by means of taking advantage of a time lag in transmitting a drive force to the ink sucking means, but also significantly simplify the drive system of the recording apparatus of this type, and thus curtail costs, miniaturize the apparatus, and reduce the time required for sequential operations by means of dispensing with a separately arranged drive force switching mechanism.
A second object of the invention is to provide an ink jet recording apparatus that can keep the ink sucking operation inoperative during recording operation by means of allowing both the sheet discharging operation by the sheet feed/discharge means and the ink sucking operation to be performed while the drive means is being rotated in a reverse direction.
A third object of the invention is to provide an ink jet recording apparatus that prevents disturbing the recording operation. That is, the apparatus can be further miniaturized by means of movably arranging the capping means of the recording head so as to enter into and overlap the cleaning means operating region. Therefore, the width of the capping means is reduced by a dimension equal to the overlap of the operating region of the cleaning means. At the same time, the apparatus can prevent the recording operation from being disturbed by having one side of the capping means function as a stopper surface to block the cleaning means from projecting. That is, the stopper surface prevents to the cleaning means from projecting and contacting the recording head as a result of the sheet forward motor having rotated in a direction opposite to the sheet forward direction.
Further, another object of the invention is to provide an ink jet recording apparatus that can record images at both side margins of a recording sheet, even in the case of using a large-sized carriage carrying a color ink tank, by allowing part of the carriage that is scanning to enter into the home position, while causing a guide means to locate the capping means having entered into the cleaning means operating region to a position where the capping means does not come in contact with the recording head.
Another object of the invention is to provide an ink jet recording apparatus that can implement highly accurate sheet forwarding by directly connecting the cleaning means or the ink sucking means to the sheet feed/discharge means through a transmission mechanism different from a transmission mechanism that transmits motive force to the sheet feed/discharge means. That is, as a result of such direct connection, backlashes caused by repetitive forward and reverse rotations of the train of gears and slippages caused by using friction clutches are eliminated, which in turn blocks load fluctuations caused by these transmission mechanisms themselves and load fluctuations accompanied by the operation of the ink sucking means from being transmitted to the sheet feed/discharge means.
Another object of the invention is to provide an ink jet recording apparatus that can increase the degree of freedom in sequencing the entire system of the recording apparatus by allowing the operation of initializing the cleaning means or the ink sucking means to be performed only by rotation of the sheet feed/disch
Isono Masahiro
Kawakami Kazuhisa
Kobayashi Atsushi
Mochizuki Seiji
Ohtsuka Nobutoshi
Seiko Epson Corporation
Stewart Jr. Charles W.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Tran Huan
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