EP0513585A2 - Druckeinheit mit Thermo-Kopf - Google Patents

Druckeinheit mit Thermo-Kopf Download PDF

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Publication number
EP0513585A2
EP0513585A2 EP92107192A EP92107192A EP0513585A2 EP 0513585 A2 EP0513585 A2 EP 0513585A2 EP 92107192 A EP92107192 A EP 92107192A EP 92107192 A EP92107192 A EP 92107192A EP 0513585 A2 EP0513585 A2 EP 0513585A2
Authority
EP
European Patent Office
Prior art keywords
platen roller
base member
thermal head
roller
printing unit
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.)
Withdrawn
Application number
EP92107192A
Other languages
English (en)
French (fr)
Other versions
EP0513585A3 (en
Inventor
Fumiaki C/O Rohm Co. Ltd. Tagashira
Shingo C/O Rohm Co. Ltd. Ooyama
Shigeo C/O Rohm Co. Ltd. Ota
Yoshinobu C/O Rohm Co. Ltd. Kishimoto
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.)
Rohm Co Ltd
Original Assignee
Rohm Co 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
Priority claimed from JP3324491U external-priority patent/JPH04126857U/ja
Priority claimed from JP15287391A external-priority patent/JP3141952B2/ja
Application filed by Rohm Co Ltd filed Critical Rohm Co Ltd
Publication of EP0513585A2 publication Critical patent/EP0513585A2/de
Publication of EP0513585A3 publication Critical patent/EP0513585A3/en
Withdrawn legal-status Critical Current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
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
    • B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
    • B41J2/325—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads by selective transfer of ink from ink carrier, e.g. from ink ribbon or sheet
    • 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
    • B41J29/00—Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for
    • B41J29/377—Cooling or ventilating arrangements

Definitions

  • This invention relates to a printing unit incorporating a thermal head. More specifically, the present invention relates to a thermal head printing unit of the type which can be advantageously used for a relatively large-sized facsimile machine or printer.
  • the illustrated printing unit comprises an elongate base member 21, a thermal head 22, a platen roller 24, and a backup roller 25.
  • the base member 21, typically made of a solid metal bar, is fixed to the facsimile or printer body (not shown) and carries the thermal head 22 on its upper surface.
  • the platen roller 24 is located above the thermal head 22, and is countered by the backup roller 25.
  • an ink transfer tape 26 is unwound from a supply roller 27, fed along a pair of guide rollers 28, 29, then introduced between the platen roller 24 and the thermal head 22, where the thermal head 22 causes ink transfer from the tape 26 onto printing paper 34.
  • the tape 26 is further pulled along a guide roller 30 by a pair of feed rollers 31, 32, and then wound up on a winding roller 33.
  • the printing paper 34 is fed between the platen roller 24 and the ink transfer tape 26 by appropriate feeding means (not shown.)
  • the backup roller 25 is located right above the platen roller 24 in contact therewith.
  • the backup roller 25 can effectively prevent the platen roller 24 from bending vertically upward away from the thermal head 22.
  • bending of the platen roller 24 is not limited to the vertical direction.
  • the tensile force also acts on the platen roller 24 in a generally horizontal direction.
  • the platen roller 24 tends to bend in the paper feed direction, as indicated by broken lines in Fig. 8. This causes deterioration in the printing quality due to uneven pressing contact between the heating dot line 23 and the platen roller 24.
  • a simple way to prevent or reduce horizontal bending of the platen roller 24 is to increase the diameter of the platen roller 24.
  • such a solution results in unacceptable increase of weight and size.
  • a primary object of the present invention to provide a printing unit wherein a platen roller can be reliably prevented from bending in the paper feed direction without increasing the diameter of the platen roller itself.
  • Another object of the present invention is to provide a printing units which, in addition to achieving the primary object, is capable of preventing a base member from bending away from the platen roller without increasing the weight of the base member and deteriorating heat dissipation from the base member.
  • a printing unit comprising: an elongate base member; a thermal head mounted on the base member and carrying a line of heating dots; a platen roller arranged to contact the heating dot line, printing paper being transferred between the thermal head and the platen roller; and a backup roller arranged farther from the thermal head than the platen roller but held parallel to the platen roller in contact therewith; characterized in that the backup roller is located ahead of the platen roller with respect to the paper transfer direction.
  • the location of the backup roller is such that it supports the platen roller against bending in the paper transfer direction when the tension applied to the paper for feeding acts on the platen roller.
  • the printing unit is prevented from a printing quality deterioration which may result from bending of the platen roller.
  • the printing unit may further comprise an additional backup roller located behind the platen roller with respect to the paper transfer direction and held parallel to the platen roller in contact therewith.
  • the additional backup roller cooperates with the first mentioned roller to prevent the platen roller from bending away from the thermal head.
  • the base member is rendered hollow to have at least one longitudinal bore which is open at both ends of the base member.
  • the base member thus configured is mechanically reinforced against bending, but the presence of the longitudinal bore reduces the weight of the base member and yet enables efficient heat dissipation by utlizing air passage.
  • the longitudinal bore of the base member may be connected to a blower means for positive ventilation of the base member.
  • a printing unit which comprises a base member 1 and a thermal head 2.
  • the base member 1 is typically made of a metal such as aluminum or aluminum alloy in a bar form, and fixed in place within a facsimile or printer body (not shown) by using suitable brackets (not shown in Fig. 1 but shown in Fig. 3 representing a different embodiment). Further, the base member 1 has an upper surface provided with a thermal head 2 which, in turn, has an upper surface formed with a line 3 of heating dots (see Fig. 3 for reference).
  • a platen roller 4 in contact with the heatig dot line 3. Further, above the platen roller 4 is arranged a metallic backup roller 5 which is held parallel to the platen roller 4 in contact therewith.
  • an ink transfer tape 6 is unwound from a supply roller 7, fed along a pair of guide rollers 8, 9, and then introduced between the platen roller 4 and the thermal head 2. Further, the ink transfer tape 6 is pulled along a guide roller 10 by a pair of feed rollers 11 , 12, and then wound up on a winding roller 13.
  • an unillustrated feeding means causes printing paper 14 to be fed between the platen roller 4 and the ink transfer tape 6, as indicated by an arrow B.
  • the thermal head 2 causes ink transfer from the ink transfer tape 6 onto the printing paper 14 for intended recordal of information.
  • One important feature of the present invention resides in that the axis of the backup roller 5 is displaced from that of the platen roller 4 by an appropriate amount e in the forward transfer direction of the ink transfer tape 6 and paper 14 while maintaining parallelism relative to the platen roller 4.
  • the backup roller 5 is located above and ahead of the platen roller 4.
  • the ink transfer tape 6 and the printing paper 14 are transferred in the arrow B direction under a tensile force applied thereto, as already described.
  • a tensile force also acts on the platen roller 4, which results in that the platen roller 4 tends to bend in the paper feed direction.
  • the platen roller 4 is supported by the backup roller 5 which is located above and ahead of the platen roller by the suitable amount e.
  • This positional relation allows the backup roller 5 to reliably prevent the platen roller 4 from bending in the paper feed direction while also preventing the platen roller 4 from bending in the direction away from the base member 1 (upwardly in Fig. 1).
  • the base member 1 is shown to be hollow with a longitudinal bore 17 extending therethrough.
  • the base member 1 is prevented from bending away from the platen roller 4 (downwardly in Fig. 1) without increasing the weight of the base member 1 itself.
  • Fig. 2 shows another embodiment of the present invention wherein the platen roller 4 is supported by two backup rollers 5a, 5b which are held in parallel to each other and to the platen roller 4.
  • One backup roller 5a front backup roller
  • the other backup roller 5b rear backup roller
  • the front backup roller 5a prevents the platen roller 4 from bending in the paper feed direction.
  • the front and rear backup rollers 5a, 5b cooperate with each other to press the platen roller 4 toward the thermal head 2, thereby preventing the platen roller 4 from bending in the direction away from the base member 1 (upwardly in Fig. 2).
  • the upward bending prevention provided by the two backup rollers 5a, 5b is more reliable than that provided by a single backup roller.
  • Figs. 3 and 4 show a printing unit according to a further embodiment of the present invention.
  • the printing unit of this embodiment incorporates a divisional-type thermal head 2' arranged on a base member 1 which, in turn, is fixed to a facsimile or printer body (not shown) by means of brackets 15 and bolts 16 (Fig. 4).
  • the printing unit further includes a platen roller and a backup roller in the same manner as shown in Fig. 1 or 2.
  • the divisional-type thermal head 2' comprises a plurality of unit thermal heads 2a' each having a unit width w and arranged in a longitudinal array to provide an overall printing length W corresponding, for example, to JIS A0 or JIS A1 size paper (JIS: Japanese Industrial Standard).
  • JIS Japanese Industrial Standard
  • the use of such a divisional-type thermal head is particularly preferred when the paper size is relatively large.
  • the base member 1 is shown to have a longitudinal bore 17 which is open at both ends 1a, 1b of the base member.
  • the base member thus configured may be made of aluminum or aluminum alloy by extrusion.
  • the hollow base member 1 is greatly reinforced against longitudinal bending without calling for a significant weight increase.
  • the longitudinal bore 17 is open at both ends 1a, 1b of the base member 1, the air within the bore 17 is heated upon actuation of the heating dot line 3 and displaced by external air through convection. As a result, heat dissipation from the base member 1 can be improved by the provision of the longitudinal bore 17.
  • the longitudinal bore 17 of the base member 1 may be connected to a blower 18 through a duct 19.
  • the longitudinal bore 17 can be positively ventilated to additionally improve heat dissipation from the base member 1.
  • Figs. 5 and 6 respectively show two different base members 1' and 1'' which may replace the base member 1 shown in Figs. 3 and 4. Specifically, the base member 1' of Fig. 5 is made to have two divided longitudinal bores 17', whereas the base member 1'' of Fig. 6 is made to have four divided longitudinal bores 17''. In either case, the base member is rendered mechanically stronger than that of Figs. 3 and 4.

Landscapes

  • Handling Of Sheets (AREA)
EP19920107192 1991-05-14 1992-04-28 Printing unit incorporating thermal head Withdrawn EP0513585A3 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP3324491U JPH04126857U (ja) 1991-05-14 1991-05-14 プリントヘツド又は固体撮影素子の取付け装置
JP33244/91U 1991-05-14
JP152873/91 1991-06-25
JP15287391A JP3141952B2 (ja) 1991-06-25 1991-06-25 サーマルヘッド使用印字装置

Publications (2)

Publication Number Publication Date
EP0513585A2 true EP0513585A2 (de) 1992-11-19
EP0513585A3 EP0513585A3 (en) 1993-05-26

Family

ID=26371922

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920107192 Withdrawn EP0513585A3 (en) 1991-05-14 1992-04-28 Printing unit incorporating thermal head

Country Status (1)

Country Link
EP (1) EP0513585A3 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2702705A1 (fr) * 1993-01-19 1994-09-23 Intermec Corp Tête d'impression thermique.
EP0622243A2 (de) * 1993-04-30 1994-11-02 Hewlett-Packard Company Luftströmungssystem für Tintenstrahldrucker
EP1338429A3 (de) * 2002-02-21 2004-07-07 Eastman Kodak Company Verfahren und Vorrichtung zur Temperatursteuerung in einem Thermodrucker mit mehreren Druckstationen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62268677A (ja) * 1986-05-19 1987-11-21 Mitsubishi Electric Corp プリンタの紙送り装置
EP0254420A1 (de) * 1986-06-19 1988-01-27 Canon Kabushiki Kaisha Verfahren und Gerät zum Aufzeichnen
US4819011A (en) * 1985-10-08 1989-04-04 Kabushiki Kaisha Sato Thermal printer temperature regulation system
US4989017A (en) * 1985-12-26 1991-01-29 Kabushiki Kaisha Toshiba Thermal print head

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4819011A (en) * 1985-10-08 1989-04-04 Kabushiki Kaisha Sato Thermal printer temperature regulation system
US4989017A (en) * 1985-12-26 1991-01-29 Kabushiki Kaisha Toshiba Thermal print head
JPS62268677A (ja) * 1986-05-19 1987-11-21 Mitsubishi Electric Corp プリンタの紙送り装置
EP0254420A1 (de) * 1986-06-19 1988-01-27 Canon Kabushiki Kaisha Verfahren und Gerät zum Aufzeichnen

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 12, no. 149 (M-694)10 May 1988 & JP-A-62 268 677 ( MITSUBISHI ELECTRIC CORP. ) 21 November 1987 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2702705A1 (fr) * 1993-01-19 1994-09-23 Intermec Corp Tête d'impression thermique.
EP0622243A2 (de) * 1993-04-30 1994-11-02 Hewlett-Packard Company Luftströmungssystem für Tintenstrahldrucker
EP0622243A3 (de) * 1993-04-30 1995-03-01 Hewlett Packard Co Luftströmungssystem für Tintenstrahldrucker.
EP1338429A3 (de) * 2002-02-21 2004-07-07 Eastman Kodak Company Verfahren und Vorrichtung zur Temperatursteuerung in einem Thermodrucker mit mehreren Druckstationen

Also Published As

Publication number Publication date
EP0513585A3 (en) 1993-05-26

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