EP0420400B1 - Printer medium drive clearance eliminator - Google Patents

Printer medium drive clearance eliminator Download PDF

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Publication number
EP0420400B1
EP0420400B1 EP19900308427 EP90308427A EP0420400B1 EP 0420400 B1 EP0420400 B1 EP 0420400B1 EP 19900308427 EP19900308427 EP 19900308427 EP 90308427 A EP90308427 A EP 90308427A EP 0420400 B1 EP0420400 B1 EP 0420400B1
Authority
EP
European Patent Office
Prior art keywords
medium
printer
drive
clearance
drive roller
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19900308427
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0420400A3 (en
EP0420400A2 (en
Inventor
John A. Underwood
Anthony W. Ebersole
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HP Inc
Original Assignee
Hewlett Packard Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hewlett Packard Co filed Critical Hewlett Packard Co
Publication of EP0420400A2 publication Critical patent/EP0420400A2/en
Publication of EP0420400A3 publication Critical patent/EP0420400A3/en
Application granted granted Critical
Publication of EP0420400B1 publication Critical patent/EP0420400B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
    • B41J13/10—Sheet holders, retainers, movable guides, or stationary guides
    • B41J13/14—Aprons or guides for the printing section
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/0045—Guides for printing material
    • B41J11/005—Guides in the printing zone, e.g. guides for preventing contact of conveyed sheets with printhead

Definitions

  • the present invention relates generally to computer printer medium drive mechanisms, and, more particularly, to drive mechanisms wherein the medium is required to curl around a roller as it feeds through the printer.
  • the predominant current usage of the medium clearance eliminator of the present invention is as an aid to paper feeding and handling in thermal ink-jet printer medium drive mechanisms.
  • a mechanism is required to move print medium, usually either paper or a transparency, through the printer.
  • the medium drive mechanism is required to advance medium smoothly and accurately and frequently both forward and backward through the printer. It usually must be capable of handling several types of medium, sometimes including both sheet medium and form feed medium, wherein the medium is supplied in a continuous length.
  • the mechanism must not be prone to jamming, since it is intended that medium handling be entirely automatic and that it not require operator intervention.
  • the mechanism must provide a proper medium exit angle appropriate to the type and design of printer to which it is adapted.
  • the mechanism must further readily accept medium that is automatically fed into it, since this is frequently a part of the automated medium handling process within a printer.
  • printer medium drive mechanisms One of the most common designs for printer medium drive mechanisms has the medium entering the mechanism between an opposed pair of rollers. The medium then curves around one roller and exits the drive mechanism in a direction essentially opposite the entering direction.
  • the drive mechanism may be placed near the back of the printer, thereby reducing overall printer size.
  • This type of drive mechanism has been found to work well, and has been in service for a considerable period of time. Nevertheless, this type mechanism is not without its problems. Among these are the fact that paper exiting the mechanism sometimes tends to skew, that is, to become improperly aligned with the print-head as its exits the drive mechanism.
  • Patent Abstracts of Japan vol. 9, no. 333 (M-443) [2056], 27th December 1985 and JP-A-60165276 describes a paper guide mechanism designed to prevent poor quality printing and skewing of the print medium.
  • the mechanism comprises a drive roller, a plurality of pinch rollers and a sub-auxiliary guide plate in the clearance between the drive roller and an auxiliary guide plate.
  • the sub-auxiliary guide plate is made of a material low in rigidity and friction resistance, such as polyester film, and the base thereof is fastened to the auxiliary guide plate.
  • the end of the sub-auxiliary guide plate remote from the auxiliary guide plate is pressed against the drive roller and curves around part of the drive roller, thereby holding the print medium tightly against that part of the roller. This prevents deflection of the print medium due to clearance between the drive roller and the auxiliary guide plate.
  • the present invention relates to computer hardcopy output printers incorporating a conventional medium drive mechanism, and further incorporating the inventive mechanism so as to eliminate jamming and skewing problems associated with the conventional medium drive mechanism.
  • the present invention is particularly adapted for use in thermal ink-jet printer assemblies.
  • the present invention provides a medium feed mechanism for a printer comprising a drive roller for propelling a print medium and at least one pinch roller for holding the print medium against the drive roller, and further comprising a clearance eliminator mechanism, including: a medium guide piece; a flexible clearance eliminator sheet mounted in tension on said medium guide piece, said clearance eliminator sheet conforming to a surface of the drive roller over at least a portion of the circumference of said drive roller.
  • the clearance eliminator sheet can be made of any of a number of different materials.
  • UHMW ultrahigh molecular weight
  • An advantage of the present invention is that jamming within a printer drive mechanism is reduced.
  • Another advantage of the present invention is that skewing of medium within a printer drive mechanism is reduced.
  • a further advantage of the present invention is that a conventional, proven and othervise desirable drive mechanism design may be employed while reducing tendencies of medium to jam or skew within the printer drive mechanism.
  • the best presently known mode for carrying out the invention is a thermal ink-jet printer incorporating conventional elements including a medium drive, or "feed" mechanism.
  • the medium feed mechanism includes the inventive medium clearance eliminator as a means for eliminating clearances within the mechanism, which would othervise allow medium within the feed mechanism to buckle, and thus cause the undesirable properties of jamming and skewing of the medium.
  • the predominant expected usage of the inventive medium clearance eliminator is in ink-jet printers used in the data processing industry and in office and home computer printer installations.
  • FIG. 1 A portion of the thermal ink-jet printer of the presently preferred embodiment of the present invention is illustrated in a side view in FIG. 1 and is designated therein by the general reference character 10 .
  • the printer 10 does not differ significantly from conventional thermal ink-jet printers.
  • the physical structure is similar to that of prior art thermal ink-jet printers.
  • the conventional elements of the printer 10 include a pen 12 for depositing ink upon a print medium 14 , a platen 16 for holding the medium 14 relatively parallel to the pen 12 during printing, and an input guide 18 for guiding the medium 14 into contact with a drive roller 20 .
  • a drive pinch roller 22 is contiguous to the drive roller 20 and parallel along its length.
  • the medium 14 is drawn through the printer 10 by the drive roller 20 and is pushed past the pen 12 and the platen 16 where it is further directed by an exit roller 24 and an exit pinch roller 26 .
  • the medium 14 is held against the drive roller 20 near the pen 12 by a drive plate 28 .
  • the pen 12 is mounted on a pen traversing mechanism (not shown), allowing the pen 12 to traverse the medium 14 in a plane parallel to the medium 14 and perpendicular to a medium advance direction 30 .
  • FIG. 2 wherein is illustrated a comparable printer assembly 10 including a conventional paper guide 32 , the drive plate 28 is affixed to the paper guide 32 , and the paper guide 32 is rigidly affixed relative to the printer assembly 10 .
  • the medium 14 is shown buckling in a clearance area 34 . Jamming of the printer 10 can occur when medium 14 buckles sufficiently in clearance area 34 so as to double back as depicted in FIG. 3.
  • the paper guide 34 is shown reshaped according to the present invention and pivotallv mounted relative to the printer assembly 10 at a pivot point 36.
  • a clearance eliminator sheet 38 is shown holding the medium 14 against the drive roller 20 .
  • the clearance eliminator sheet 38 is made of a flexible ultra-high molecular weight (UHMW) polyethylene so that it may conform somewhat to the shape of the drive roller 20 .
  • the clearance eliminator sheet 38 is rigidly mounted at a top mounting tab 40 and a bottom mounting tab 42 so as to allow for this flexibility.
  • Bottom mounting tab 42 is slidingly mounted to the paper guide 32 and is tensioned by coil spring 43 so as to hold the clearance eliminator sheet 38 firmly against the drive roller 20 .
  • the force holding the clearance eliminator sheet 38 against the drive roller 20 is provided by coil spring 43 , which is secured at one end by spring mounting pivot 46 .
  • the clearance eliminator sheet 38 is made of ultra-high molecular weight (UHMW) polyethylene sheet. While any of a number of relatively low friction materials might be used, UHMW polyethylene has been found to provide the best combination of low friction, flexibility, and wear resistance. UHMW polyethylene is well-known and commercially available.
  • the thickness of UHMW polyethylene sheet while not being particularly critical, is about 127 ⁇ m (0.005 inch).
  • the drive plate 28 is also surfaced with UHMW polyethylene in the area of contact with the medium 14 .
  • the paper guide 32 may be pivotally mounted as shown or rigidly affixed to the input guide 28 or an extension thereof. Another spring (not shown), or its equivalent, causes the paper guide 32 to rotate in the direction indicated by arrow 52 .
  • the pivot point 36 is provided in the presently preferred embodiment of the present invention as a means for biasing the drive plate 28 against the drive roller 20 .
  • the clearance area 34 (FIG. 2) is greatly reduced.
  • the medium 14 does pass through two residual unsupported areas 54 .
  • the medium 14 is sufficiently stiff to pass through these short residual unsupported areas 54 without buckling. Accordingly, the improvements of the present invention effectively eliminate jamming in the area of the drive roller 20 and the paper guide 32 .
  • the medium cannot become skewed in this area, as elimination of the clearance area 34 prevents either side of the medium 14 from advancing ahead of the other.
  • tension may be provided by means other than a coil spring 43 .
  • Tension points and pivot points may also be altered as necessary to adapt the inventive clearance eliminator to various printer drive mechanisms. Another conceivable alteration would be to adapt the inventive clearance eliminator to printer types other than thermal ink-jet printers.
  • Ink-jet printers incorporating the present invention may be utilized in any application wherein conventional ink-jet printers or other conventional computer hardcopy output printers are currently used. Since computer printers utilizing the present invention may be readily constructed and do not require that an operator vary the manner in which such printers are used, it is expected that they will be acceptable in the industry as substitutes for conventional printers. The increased reliability and improvement in medium feed qualities will make printers incorporating the present invention desirable substitutes and will enhance the applicability of the present invention.

Landscapes

  • Delivering By Means Of Belts And Rollers (AREA)
  • Handling Of Continuous Sheets Of Paper (AREA)
  • Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
  • Handling Of Cut Paper (AREA)
  • Advancing Webs (AREA)
  • Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
EP19900308427 1989-09-29 1990-07-31 Printer medium drive clearance eliminator Expired - Lifetime EP0420400B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US41483089A 1989-09-29 1989-09-29
US414830 1989-09-29

Publications (3)

Publication Number Publication Date
EP0420400A2 EP0420400A2 (en) 1991-04-03
EP0420400A3 EP0420400A3 (en) 1991-06-12
EP0420400B1 true EP0420400B1 (en) 1995-01-04

Family

ID=23643153

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900308427 Expired - Lifetime EP0420400B1 (en) 1989-09-29 1990-07-31 Printer medium drive clearance eliminator

Country Status (4)

Country Link
EP (1) EP0420400B1 (ja)
JP (1) JP2886312B2 (ja)
CA (1) CA2014652A1 (ja)
DE (1) DE69015749T2 (ja)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5648807A (en) 1992-09-10 1997-07-15 Seiko Epson Corporation Ink jet recording apparatus having an antismear sheet deformation discharge system
US5516222A (en) * 1995-01-04 1996-05-14 Brother International Corporation Printing device having limited movement paper guide
US5527123A (en) * 1995-02-28 1996-06-18 Hewlett-Packard Company Media handling in an ink-jet printer
JPH10202964A (ja) * 1996-11-21 1998-08-04 Fuji Photo Film Co Ltd カラーサーマルプリント方法及びプリンタ
JP3022849B2 (ja) * 1998-01-05 2000-03-21 セイコーエプソン株式会社 プリンタ

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE235917C (ja) *
DE2946033C2 (de) * 1979-11-14 1982-08-19 Siemens AG, 1000 Berlin und 8000 München Papiereinzugsvorrichtung für Druckeinrichtungen
JPS60165276A (ja) * 1984-02-07 1985-08-28 Ricoh Co Ltd 印字装置の用紙案内機構
DE3441954A1 (de) * 1984-11-16 1986-05-22 Olympia Werke Ag, 2940 Wilhelmshaven Papierfuehrung fuer druckeinrichtungen
KR940010997B1 (ko) * 1987-03-23 1994-11-22 세이꼬 엡슨 가부시끼가이샤 프린터
US4843338A (en) * 1987-10-23 1989-06-27 Hewlett-Packard Company Ink-set printhead-to-paper referencing system
DE3802532A1 (de) * 1988-01-28 1989-08-10 Siemens Ag Papierfuehrungseinrichtung fuer druckeinrichtungen

Also Published As

Publication number Publication date
DE69015749T2 (de) 1995-05-11
JPH03173663A (ja) 1991-07-26
JP2886312B2 (ja) 1999-04-26
CA2014652A1 (en) 1991-03-29
DE69015749D1 (de) 1995-02-16
EP0420400A3 (en) 1991-06-12
EP0420400A2 (en) 1991-04-03

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