Synchronized carriage and wiper motion method and apparatus for ink-jet printers

• US 5,396,277 A
• Filed: 09/25/1992
• Issued: 03/07/1995
• Est. Priority Date: 09/25/1992
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Company (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Shibata, Alan, Gast, Paul D., Moon, Eva-Maria
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): HALLACHER, CRAIG ALAN
• Application Number:
  US07/951,276
• Time in Patent Office: 893 Days
• Field of Search: 346/140 R, 347/33
• US Class Current: 347/33
• CPC Class Codes: B41J 2/16538 with brushes or wiper blades perpendicular to the nozzle plate

Abstract

A synchronized wiper and pen motion solution for ink-jet printers is described. The invented method and apparatus synchronize the motion of the pen and wiper throughout the wipe stroke, and provide for controlled, simultaneous movement therebetween that avoids pole vaulting, excess interference and ink flicking. Such is accomplished by moving the carriage to a defined position shy of a wiping position above the service station including a sled mounting the wiper; raising the sled to produce a proper interference fit between the wiper and the pen while simultaneously moving the carriage at low speed; continuing the wipe stroke by high-speed carriage movement with the sled stationary; and, at the end of the stroke, lowering the sled to clear the wiper from contact with the pen before reversing carriage motion. The solution lends itself to single- or plural-pen ink-jet printers.

Claims

1. An ink-jet printer pen wiping method wherein a pen is mounted on a horizontally movable carriage such that its working surface is at a given level and wherein a wiper having a tip is mounted on a vertically movable sled forming part of a service station of the printer, with movement of the carriage and sled being provided by one or more motors responsive to a controller of the printer, the method comprising the step of:

positioning the sled at a first predefined elevation relative to the carriage such that the wiper is below the level of the pen;

first moving the carriage in a first direction to a position above the service station while concurrently moving the sled to a second predefined elevation relative to the carriage, thereby producing controlled-direction flexure of the wiper as the tip of the wiper comes into interference contact with the pen;

wiping the pen with the wiper by a second movement of the carriage in the first direction in such position above the service station relative to the sled with the wiper remaining in interference contact with the pen; and

ceasing said second moving of the carriage before the wiper reaches a far end of the pen.

wherein said first moving of the carriage is performed at a first predefined speed as the wiper tip comes into said pen contact and wherein said second moving of the carriage is performed at a second predefined speed as the wiper wipes the pen, such second predefined speed being substantially greater than such first predefined speed.

2. The method of claim 1 which further comprises lowering the sled proximate in time to said ceasing to a second predefined elevation relative to the carriage in which the wiper is clear of the pen.

3. The method of claim 2 which further comprises third moving the carriage in reverse of such first direction, wherein said third moving is performed after said lowering.

4. An apparatus for use in an ink-jet printer having a printhead mounted on said carriage, a chassis and a pen-wiping station positioned generally along a reciprocal motion axis of said printhead carriage for selective wiping of one or more pens of said printhead mounted on the carriage, the appartus comprising:

a sled forming a part of the pen-wiping station, said sled mounting one or more wipers, said sled being mounted relative to the chassis of the printer for vertical movement relative thereto into a pen-wiping elevation relative to the printhead when the carriage is moved into a service position;

a motor operatively connected with the carriage and with said sled for moving said sled into operative pen-wiping engagement with the printhead responsive to a first control signal; and

a controller coupled with said motor, said controller producing said first control signal, thereby providing for synchronous generally horizontal movement of the carriage and generally vertical movement of said sled by way of said first control signal, thereby to wipe the pen mounted on the carriage, said control signal causing said motor to move the carriage at a first predefined speed until said sled is moved into operative pen-wiping engagement and for a predetermined wiping period of time thereafter to move the carriage at a second predefined speed that is substantially greater than such first predefined speed and after such predetermined period of time to move the carriage at a third predefined speed that is substantially less than such second predefined speed and thereafter causing the motor to lower said sled out of operative pen-wiping engagement,

wherein said controller provides for horizontal movement of the carriage by way of a second control signal to a motor operatively coupled with the carriage, and wherein said synchronous movements include simultaneously horizontal movement of said carriage in proximity to said sled and upward vertical movement of said sled when a pen-wiping commences as said sled-mounted wiper first engages the pen.

5. The apparatus of claim 4, wherein said controller further provides for the carriage'"'"'s horizontal movement to stop before said wiper reaches an edge of the pen.

6. The apparatus of claim 5, wherein said controller further provides for the sled'"'"'s downward vertical movement to disengage said wiper from the pen closely proximate in time with such stop of the carriage'"'"'s movement.

7. The apparatus of claim 6, wherein said controller further provides for the carriage'"'"'s reverse horizontal movement after said wiper is disengaged from the pen.

8. The apparatus of claim 7, wherein said controller further provides for reverse direction pen wiping with said synchronous movement of the carriage and said sled by said controller.

9. The apparatus of claim 4, wherein said controller provides for same-direction, plural-speed horizontal movement of the carriage, with lower speed movement during first engagement of said wiper with the pen and with higher speed movement thereafter.

10. The apparatus of claim 9, wherein said higher speed movement is substantially higher than said lower speed movement.