Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-04-05
2004-08-03
Meier, Stephan D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S022000, C347S029000, C347S030000, C347S031000, C347S033000
Reexamination Certificate
active
06769758
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cleaning device for wiping a nozzle surface of an ink-jet head in an ink-jet printer, and an ink-jet printer employing the cleaning device.
2. Description of the Related Art
An ink-jet printer performs printing on a printing paper by ejecting ink droplets from respective ink nozzles of an ink-jet head. Upon occurrence of clogging of respective ink nozzles, printing quality can be lowered, and, in worst case, printing becomes impossible. Clogging of the ink nozzle can be caused when the ink in the ink nozzle is dried to increase viscosity or when paper dust deposits on the nozzle surface where the ink nozzles are arranged.
Therefore, a cleaning device is mounted in the ink-jet printer. A carriage mounting the ink-jet head is regularly moved to the position to oppose the cleaning device which is positioned out of printing range. Then, the cleaning device is used to wipe the nozzle surface and discharge ink of increased viscosity from the ink nozzles.
The typical cleaning device includes a lock lever for locking the ink-jet head carried by the carriage at a cleaning position, a head cap for covering the nozzle surface of the ink-jet head locked at the cleaning position, an ink suction pump for forcedly sucking the ink from respective ink nozzles in the condition where the head cap is fitted, and a wiper blade formed with a rubber plate or the like for wiping the nozzle surface. The wiper blade is moved to a wiping position capable of contacting with the nozzle surface only when the nozzle surface is wiped, so that the wiper blade is prevented from unnecessary wearing. On the other hand, the lock lever and the wiper blade are driven by a driving motor of an ink suction pump from a viewpoint of down-sizing of the device and whereby for obtaining compact ink-jet printer.
As the wiper blade in the cleaning device of the ink-jet printer, one has been proposed in Japanese Unexamined Patent Publication No. Showa 62-251145. In this publication, the wiper blade includes a main blade constructed rotatably and a sub-blade fixed within a region where the main blade moves. The ink or the like deposited on the main blade is wiped by the sub-blade for preventing the deposit on the main blade from being transferred back to the nozzle surface.
It has also been proposed that, from a viewpoint of preventing clogging of the ink nozzles, the ink-jet printer has the ink-jet head whose nozzle surface faces downward. In the ink-jet printer of this type, with respect to the ink-jet head which reciprocates horizontally with the nozzle surface facing downward, the wiper blade is elevated upward from below to wipe the nozzle surface.
However, in the cleaning device which moves the wiper blade up and down, since the ink-jet head passes horizontally above the device, paper dust or the like deposited on the nozzle surface may drop into an opening portion where the wiper blade passes, to deposit on the wiper blade. Deposition of foreign matter, such as paper dust, on the wiper blade is not desirable because it may be deposited again on the nozzle surface during wiping of the nozzle surface.
Therefore, the sub-blade may be placed within the motion path of the wiper blade and wipe it for removing the foreign matter deposited thereon. However, unless the contact condition is appropriately controlled, both blades may wear within a short period. Of course, wearing of the wiper blade can be reduced by shifting the sub-blade. However, since the member for moving the sub-blade has to be provided separately, the number of parts is inherently increased.
Next, in the conventional cleaning device, in view of reduction in number of parts of the device and down-sizing of the printer, the driving motor of the ink suction pump is also used as a driving source of the wiper blade and the lock lever. In general, rotational torque of the driving motor of the ink suction pump is taken out via a friction type power transmission path to deliver to the wiper blade and the lock lever.
When the wiper blade is moved in a condition that it is contacted with the sub-blade, due to a frictional force between the blades, a large driving force is required in comparison with the case where the wiper blade is driven to move without contacting the sub-blade. The conventional driving mechanism is, however, designed to transmit power only by means of frictional force, so that the driving force for the wiper blade tends to lack, and the wiper blade may not be moved. Likewise, if an external force acts on the wiper blade while moving in a certain cause, the wiper blade may be impossible to move.
In order to obtain a reliable movement of the wiper blade, the driving force to be transmitted must be increased. However, since the friction type power transmission path to the wiper blade and the lock lever from the ink suction pump is common, the driving force for moving the lock lever is inevitably increased. If the driving force for moving the lock lever becomes large, the following problem may occur.
Namely, since position control of the ink-jet head is performed precisely, it can be expected that the ink-jet head may be accurately positioned in opposition to the cleaning device. However, when unexpected external force is applied, the ink-jet head may stop at a position offsetting from the position opposing to the cleaning device, namely a locking position by the lock lever. In such cases, when the driving force for moving the lock lever is excessively large, the ink-jet head may be damaged by the lock lever.
On the other hand, the friction type power transmission path for transmitting the driving force to the lock lever and the wiper blade, is constituted by a rotary type friction clutch to which a rotational torque of the driving motor of the ink suction pump is transmitted, and a cam mechanism for converting rotational motion into a reciprocal motion of the wiper blade and the lock lever.
In this case, depending upon rotational amount of the friction clutch, the wiper blade and the lock lever are moved linearly in reverse directions. Namely, when the cleaner lever is moved to a wiping position where it contacts with the nozzle surface, the lock lever is moved to an unlock position, and conversely, when the wiper blade is moved away from the nozzle surface, the lock lever reaches a lock position for locking the ink-jet head.
Since the wiping position of the wiper blade and the lock position of the lock lever are predetermined, strokes of respective levers are determined on the basis of these positions. As a result, the stoke of each lever has to be excessively long in comparison with a case where both levers are moved by separate power transmission paths or driving sources, which is undesirable for down-sizing of the cleaning device.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a cleaning device having a main wiper member for wiping a nozzle surface of an ink-jet head and a sub-wiper member for wiping the main wiper member, which is capable of reducing wearing of these wiper members.
Another object of the present invention is to provide a cleaning device having a main wiper member for wiping a nozzle surface of an ink-jet head and a sub-wiper member for wiping the main wiper member, which can prevent deposition of foreign matter, such as paper dust dropping from the ink-jet head, on the main wiper member.
A further object of the present invention is to provide a cleaning device having a wiper member for wiping a nozzle surface of an ink-jet head, which is able to certainly move the wiper member between a wiping position and a retracted position thereof.
A still further object of the present invention is to provide a cleaning device which converts a rotational torque taken out via a friction clutch from a common rotational driving source into a linear motion of a lock lever for locking an ink-jet head via a cam mechanism and into a linear motion of a cleaner lever mounted on the wiper member for wiping a nozzle surface of the ink-jet h
Nishioka Atsushi
Sasaki Toshiyuki
Wanibuchi Hiroshi
Hogan & Hartson LLP
Meier Stephan D.
Seiko Epson Corporation
Tran Ly T
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