EP0143467B1 - Adjusting device for dimensionally adjusting a gap between a platen and a print head assembly and printer using the adjusting device - Google Patents

Adjusting device for dimensionally adjusting a gap between a platen and a print head assembly and printer using the adjusting device Download PDF

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Publication number
EP0143467B1
EP0143467B1 EP84114467A EP84114467A EP0143467B1 EP 0143467 B1 EP0143467 B1 EP 0143467B1 EP 84114467 A EP84114467 A EP 84114467A EP 84114467 A EP84114467 A EP 84114467A EP 0143467 B1 EP0143467 B1 EP 0143467B1
Authority
EP
European Patent Office
Prior art keywords
platen
shaft
adjusting
cam
gap
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
Application number
EP84114467A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0143467A2 (en
EP0143467A3 (en
Inventor
Kazuhiro C/O Nec Home Electronics Ltd Agata
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.)
NEC Home Electronics Ltd
Original Assignee
NEC Home Electronics Ltd
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 NEC Home Electronics Ltd filed Critical NEC Home Electronics Ltd
Publication of EP0143467A2 publication Critical patent/EP0143467A2/en
Publication of EP0143467A3 publication Critical patent/EP0143467A3/en
Application granted granted Critical
Publication of EP0143467B1 publication Critical patent/EP0143467B1/en
Expired 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
    • 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
    • B41J11/20—Platen adjustments for varying the strength of impression, for a varying number of papers, for wear or for alignment, or for print gap adjustment

Definitions

  • the present invention relates to an adjusting device for dimensionally adjusting a gap between a platen and a print head assembly according to the preamble of the main claim.
  • the invention also relates to a printer using this adjusting device.
  • the invention is in the field of an impact type printer in which the printing heads are selectively hammered to print upon a printing sheet set on a platen, and refers more particularly to an adjusting device in the impact type printer which dimensionally adjusts a gap defined between the platen and the printing heads.
  • a non-rotating platen is mounted in side plates which are slidably mounted in side walls and which after adjustment of the gap have to be secured in position by clamping screws.
  • This object is solved by the adjusting device as defined in the main claim. Further advantageous features of the adjusting device according to the invention are evident from the subclaims 2 and 3.
  • the invention also provides for a printer which takes advantage of the adjusting device and which is disclosed in claim 4. Further advantageous features of this printer are evident from the subclaims 5 to 7.
  • a printing adjusting device is provided in an impact type printer in which the dimension of the gap between the platen and the printing heads can be positively adjusted to compensate for the varying thicknesses of printing sheets, for example, and which is simple in construction and low in manufacturing cost.
  • the printing adjusting device of the present invention is particularly well suited for use in a printer in which printing heads are hammered to print upon a printing sheet fed along the cylindrical surface of a platen.
  • the adjusting device generally includes first and second guide shafts supported on a pair of base frames in such a manner that the guide shafts are in parallel orientation with one another.
  • a printing mechanism carrying printing heads is movably mounted on the guide shafts for reciprocal rectilinear movements therealong.
  • a pair of side frames to journally mount the platen therebetween are coupled to the first guide shaft and are pivotal in a vertical plane about the axis established by the first guide shaft.
  • the side frames are also coupled through cams to the second guide shaft.
  • the cams pivot the side frames about the first guide shaft.
  • the platen being mounted on the side frames, is displaced through an arc towards and away from the printing heads in dependence upon the direction of pivotal movement of the side frames.
  • the present invention includes a pair of base frames 11 which are rigidly fixed on a base plate 10 in such a manner that base frames 11 are separated yet in parallel orientation with one another.
  • Parallel adjusting and supporting shafts 12,13 are provided so as to span the distance between the base frames 11.
  • a recessed cut section 12b is defined in the cylindrical surface of the adjusting shaft 12 and extends for a predetermined dimension between the base plates 11 in the longitudinal direction of shaft 12.
  • a head carriage 14 is mounted for reciprocal movements along both of the adjusting shaft 12 and the supporting shaft 13. More specifically, the supporting shaft 13 is inserted into hole 14a defined through the body 14b of the head carriage 14, while the adjusting shaft 12 is inserted through aligned holes 14c formed through a pair of supporting frames 141 which extend from the body 14b of the head carriage 14 towards support wall 26. (Only one frame 141 and its corresponding hole 14c are shown in Figures 1 and 2.)
  • a printing mechanism 16 is fixedly provided on the head carriage 14 and includes a plurality of printing heads 15 arranged in side-by-side fashion in the direction of a printing line upon a printing sheet (e.g. parallel to the longitudinal direction of shafts 12, 13.)
  • a pair of side frames 17 are provided on the outer surfaces of the base frames 11, respectively.
  • Two end portions 12a of the adjusting shaft 12 protrude outwardly from the outer surfaces 11 a of base frames 11 and are fixedly mated with a respective aperture 17a defined substantially at the middle portions of the side frames 17 as shown more clearly in Figure 2.
  • the side frames 17 define cam grooves 171 which are sized and configured to accept a respective one of the rotatable eccentric cams 18 provided at both ends of the supporting shaft 13.
  • cam grooves 171 are defined by a pair of vertically separated planar surfaces 171a, 171b which permit free eccentric rotation of cams 18 therebetween and thus provide bearing surfaces against which the cams 18 bear.
  • the side frames 17 pivot about an axis established by the adjusting shaft 12 through an angle corresponding to the amount of eccentricity (1) of the eccentric cams 18 due to the cams 18 eccentrically bearing against the surfaces 171a, 171b of cam grooves 171.
  • a platen 20 is journally supported between the side frames 17 by means of central shaft 21. More specifically, the side frames 17 define receiving grooves 172 respectively formed in the upper edge portions 172a thereof. End portions 21a of the central shaft 21 longitudinally extend from both ends of the platen 20 and define an annular recess 21 b registrable with receiving grooves 172 so as to be rotatably supported thereby.
  • the platen 20 is positioned over the two shafts 12 and 13 by means of the side frames 17 in such a manner that the platen 20 confronts the printing heads 15.
  • the platen 20 is responsively moved through a slight arc so as to be displaced towards or away from the printing heads 15 in dependence upon the direction of pivotal movement of the side frames 17 about shaft 12.
  • An arcuate paper guide 22 is fixedly held between the base frames 11 and is positioned in such a manner that a gap of predetermined dimension is defined between the platen 20 and the paper guide 22.
  • a printing sheet is thus insertable into the gap and is arcuately guided along the platen 20 by the paper guide 22.
  • a plurality of slots 23 are formed in the bottom of the paper guide 22 in such a manner that the slots 23 are aligned in the longitudinal direction of the paper guide 22 so as to accept respective ones of a plurality of pressure rollers 24. Thus, a portion of each roller 24 extends through its respective slot 23 so as to press a printing sheet against the platen 20.
  • the pressure rollers 24 are longitudinally arranged relative to platen 20 on a respective leaf spring member 25.
  • Each pressure roller 24 has a central shaft 241 rotatably engaged with opposing recesses 251 formed in the leaf spring member 25.
  • the leaf spring member is preferably a rectangular flat plate with the pressure rollers 24 extending across rectangular holes 251a formed in the leaf spring member 25.
  • One side portion 25a of the leaf spring member 25 is coupled to the upper edge 26a of mounting wall 26 on the base plate 10.
  • the one side portion 25a of the leaf spring member 25 is preferably secured to the upper edge 26a of the mounting wall 26 by mating engagement between the supporting pieces 261 of wall 26 and mounting holes 252 formed in the one side portion 25a.
  • the other side portion 25b of the leaf spring member 25 rests upon the recessed cut portion 12b of the adjusting shaft 12.
  • the leaf spring member 25 is vertically displaced against its bias force through an angle corresponding to the step between the cylindrical surface of the shaft 12 and the recessed cut portion 12b.
  • the recessed cut portion 12b and the cylindrical surface of the shaft 12 establishes a cam which displaces the pressure rollers 24 into and out of pressing engagement relative to the printing sheet on the platen 20 in response to rotation of the shaft 12 in opposite rotational directions, respectively.
  • the printing sheet is inserted from above between the platen 20 and the paper guide 22 and is held between the platen 20 and the pressure rollers 24 as previously described.
  • the platen 20 rotates about its longitudinal axis established by central shaft 21, the printing sheet is respectively moved along the cylindrical surface of the platen 20, guided by the paper guide 22, so that it exits towards the left platen 20 as viewed in Fig. 3.
  • the printing heads 15 of the printing mechanism 16 are then caused to confront printing hammers (not shown), such that the printing heads 15 are selectively hammered to print upon the printing sheet on the platen 20.
  • the guide shaft 13 is manually pivotal through a predetermined angle by manipulation of an adjusting lever 30.
  • the eccentric cams 18 are responsively pivoted about their eccentric axis (established by shaft 13) in the cam grooves 171, respectively, so that the side frames 17 are pivoted in a vertical plane through an arc as indicated by the arrow 100a in Figures 4 and 5.
  • the platen 20 coupled to the side frames 17 is thus responsively moved towards or away from the printing heads 15 as indicated by the arrow 101 in Figure 5 to change the dimension of gap d defined between the platen 20 and the printing heads 15.
  • the gap d defined between the platen 20 and printing heads 15 can be adjusted to an optimum dimension for uniform printing purposes so as to accommodate the particular thickness of the printing sheet being utilized, for example. Accordingly, the printing pressure of the printing heads 15 can be set to an optimum value in dependence upon the thickness of a printing sheet.
  • the present invention is also applicable to a serial-type printer.
  • the present invention can also be advantageously utilized with a pin feed type printer or a tractor- feed type printer in addition to the friction-feed type printer described above.
  • Guide shaft 13 could also be pivoted automatically through e.g. motor drive units rather than manually as described herein.

Landscapes

  • Handling Of Sheets (AREA)
  • Common Mechanisms (AREA)
EP84114467A 1983-11-29 1984-11-29 Adjusting device for dimensionally adjusting a gap between a platen and a print head assembly and printer using the adjusting device Expired EP0143467B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP22511083A JPS60116485A (ja) 1983-11-29 1983-11-29 プリンタ
JP225110/83 1983-11-29

Publications (3)

Publication Number Publication Date
EP0143467A2 EP0143467A2 (en) 1985-06-05
EP0143467A3 EP0143467A3 (en) 1985-07-10
EP0143467B1 true EP0143467B1 (en) 1988-08-31

Family

ID=16824131

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84114467A Expired EP0143467B1 (en) 1983-11-29 1984-11-29 Adjusting device for dimensionally adjusting a gap between a platen and a print head assembly and printer using the adjusting device

Country Status (3)

Country Link
EP (1) EP0143467B1 (enrdf_load_stackoverflow)
JP (1) JPS60116485A (enrdf_load_stackoverflow)
DE (1) DE3473746D1 (enrdf_load_stackoverflow)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8722622D0 (en) * 1987-09-25 1987-11-04 Halo Retail Systems Ltd Dot-matrix printers
JPH0538851A (ja) * 1991-08-07 1993-02-19 Seiko Epson Corp 印字装置
DE69620081T2 (de) * 1995-08-28 2002-11-21 Gregoire Alexandroff Doppeltradwindkraftturbine
JP3488366B2 (ja) 1997-07-18 2004-01-19 スター精密株式会社 プリンタ
US6450710B1 (en) * 2000-07-14 2002-09-17 Lexmark International, Inc. Frame system for an ink jet printer

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL6912334A (enrdf_load_stackoverflow) * 1968-09-05 1970-03-09
DD111850A1 (enrdf_load_stackoverflow) * 1974-03-11 1975-03-12
JPS5394720U (enrdf_load_stackoverflow) * 1976-12-28 1978-08-02
DE3008540C2 (de) * 1980-03-06 1982-07-22 Triumph-Adler Aktiengesellschaft für Büro- und Informationstechnik, 8500 Nürnberg Vorrichtung an Schreibwalzenlagergestell von Schreib- oder ähnlichen Maschinen zum Verstellen der Schreibwalze in Abdruckrichtung

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENTS ABSTRACTS OF JAPAN, Vol. 5, No. 61, (M-65) (733), April 24, 1981 & JP-A-56 15 379 (RICOH K.K.) (14-02-1981) *
PATENTS ABSTRACTS OF JAPAN, Vol. 7, No. 47, (M-196) (1192), February 24, 1983 & JP-A-57 195 678(RICOH K.K.) (01-12-1982) *

Also Published As

Publication number Publication date
JPS60116485A (ja) 1985-06-22
EP0143467A2 (en) 1985-06-05
EP0143467A3 (en) 1985-07-10
DE3473746D1 (en) 1988-10-06
JPH0214197B2 (enrdf_load_stackoverflow) 1990-04-06

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