EP0412179A1 - Dispositif d'encrage pour imprimante thermique par transfert - Google Patents

Dispositif d'encrage pour imprimante thermique par transfert Download PDF

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Publication number
EP0412179A1
EP0412179A1 EP89114577A EP89114577A EP0412179A1 EP 0412179 A1 EP0412179 A1 EP 0412179A1 EP 89114577 A EP89114577 A EP 89114577A EP 89114577 A EP89114577 A EP 89114577A EP 0412179 A1 EP0412179 A1 EP 0412179A1
Authority
EP
European Patent Office
Prior art keywords
roller
inking unit
inking
dye
unit according
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Withdrawn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
EP89114577A
Other languages
German (de)
English (en)
Inventor
Hubert Dipl.-Ing.(Fh) Mugrauer
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.)
Wincor Nixdorf International GmbH
Original Assignee
Siemens AG
Wincor Nixdorf International GmbH
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 Siemens AG, Wincor Nixdorf International GmbH filed Critical Siemens AG
Priority to EP89114577A priority Critical patent/EP0412179A1/fr
Publication of EP0412179A1 publication Critical patent/EP0412179A1/fr
Withdrawn legal-status Critical Current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
    • B41J31/00—Ink ribbons; Renovating or testing ink ribbons
    • B41J31/14—Renovating or testing ink ribbons
    • B41J31/16—Renovating or testing ink ribbons while fitted in the machine using the ink ribbons

Definitions

  • the invention relates to an inking unit for a thermal transfer printing device according to the preamble of the main claim.
  • thermo transfer printing device with a regenerable dye carrier which is designed as an endless belt and coated with a thermoplastic printing ink with a low melting point.
  • the dye carrier After passing through a printing station of the thermal transfer printing device, the dye carrier is passed through a heated inking unit in order to completely regenerate the dye layer there.
  • the inking unit contains further liquefied printing ink in a heated tub, which is fed via a system of application rollers and doctor blades to the surface of the dye carrier that has to be re-coated after melting.
  • the purpose of this known device is to continuously re-coat the dye carrier, which is designed as an endless belt, after it has passed through the printing station, ie to restore the dye layer over the entire surface with a layer thickness that is as uniform as possible.
  • the printing ink applied to the dye carrier in the liquid state solidifies by cooling after leaving the inking unit.
  • the regenerated dye carrier runs into the printing station again. There, energy is transferred locally to the dye carrier with the aid of a printhead, so that the dye layer is locally plasticized again and in this state is transferred point by point to a recording medium which is under pressure.
  • inking units of this type are used conventionally for the large-area coating of, for example, carbonless forms with an ink layer, and in these applications, the aforementioned sharp tolerance conditions with regard to the layer thickness do not exist. It is even more important, however, that conventional hot carbon inking units are not designed to regenerate a dye carrier.
  • the invention is therefore based on the object of providing an inking unit for a thermal transfer printing device of the type mentioned at the outset which, with a construction which is as simple as possible, allows the dye carrier to be continuously regenerated by uniformly applying a dye layer with a predetermined, closely tolerated layer thickness.
  • This solution takes into account that only a small percentage of the dye layer is used in the line-by-line printing process.
  • the dye carrier is regenerated without loss.
  • the ink remaining on the dye carrier is melted back when it enters the inking unit and squeezed.
  • the entire surface of the dye carrier is re-coated by a defined supply of liquid printing ink.
  • the ink application is carried out so that the liquefied dye present in the application area is evenly distributed on the dye carrier under pressure.
  • the ink pan as well as the pressure roller and the ink roller are heated and kept in operation at a predetermined temperature, depending on the melting point of the thermoplastic printing ink used.
  • the pressure roller and the inking roller are arranged in relation to one another in such a way that the remelted printing ink is largely completely squeezed out in the inlet area of the two rollers.
  • the inking roller transports a defined amount of dye into the outlet area of the two rollers in recesses arranged in a grid.
  • these depressions can be formed in different, negative point grids.
  • a dye carrier 1 which is designed as an endless belt, guided over rollers 2, rotates continuously.
  • the dye carrier 1 has a carrier layer of a few ⁇ m thick made of plastic, for example made of polyimide. As will be described in detail below, this is coated over the entire surface with a thermoplastic printing ink of low melting point.
  • Such printing inks are known as cold set or hot carbon inks. These printing inks consist of waxes and wax-like products, in which color pigments and carbon blacks are finely dispersed in the liquid state during production. Conventionally, these printing inks are used in particular as coatings for carbonless form sets. However, it is also already known to use this type of printing ink for regenerable dye supports in thermal transfer printers, so that a further explanation does not appear to be necessary here.
  • the dye carrier 1 rotates continuously in a clockwise direction and in the process reaches a printing station in which it comes into contact with a sheet or tape-shaped recording medium 3.
  • the direction of transport of the recording medium 3 is indicated by an arrow 4.
  • the recording medium is guided over a driven pressure roller 5, which is arranged on the side facing away from the dye carrier 1.
  • a pressure comb 6 which can be swung out against a biasing force is provided on the side facing the dye carrier 1.
  • Printing combs for thermal transfer printing devices are known per se. In principle, they have a large number of individual switching cells which are arranged along a line running transversely to the transport direction of the dye carrier 1 or of the recording medium 3. Is the print comb as optical Character generator, then these switching cells are optical switching elements that can be activated selectively, controlled by pressure information, and thus transmit radiation energy in micro picture elements to the dye carrier 1.
  • the radiation energy impinging in the micro pixels is dimensioned such that it plasticizes the printing ink adhering to the dye carrier 1 in this pixel. Since the dye carrier 1 is in contact with the recording medium 3 in the area of the printing station due to the function of the pressure roller 5, the dye plasticized in the micro pixel is transferred to the recording medium 3.
  • This process takes place simultaneously in all the micro picture elements arranged transversely to the transport direction of the record carrier 3, so that a micro image line is printed out on the record carrier 3 at the same time.
  • the dye carrier 1 After leaving the printing station, the dye carrier 1 is thus partially stripped, as is schematically indicated in FIG. 1. To regenerate the dye layer, the dye carrier 1 is therefore guided over an inking unit 7 arranged behind the printing station.
  • This consists of a heated tub 71, in which a supply of printing ink is kept liquid.
  • a counter-clockwise ink roller 72 is immersed in this tub, which takes printing ink from the tub 71 as it rotates.
  • the printing ink entrained by the inking roller is at least partially retained by a doctor blade 73 which is arranged with its cutting edge obliquely against the peripheral surface of the inking roller 72.
  • a pressure roller 74 is arranged parallel to the axis of the ink roller 72 and is partially wrapped around by the dye carrier 1 and rotates clockwise. The pressure roller 74 presses the dye carrier 1 with its dye layer side against the ink roller 72, so that the dye carrier is again coated over its entire area with printing ink.
  • This inking unit 7 is shown in FIG. 2 in a three-dimensional partial view to explain the coating process in further detail.
  • a section of the dye carrier 1 is shown schematically, from whose dye layer, not shown to scale, a letter "T" was released during the printing process.
  • both the tub 71 and the inking roller 72 and the pressure roller 74 are heated.
  • an electrical resistance heater is expediently used, since an electrical supply is necessary anyway in the case of a thermal transfer printing device.
  • the operating temperature of the heated elements of the inking unit 7 is kept above the melting temperature of the printing ink.
  • the melting temperature is in the order of magnitude of approximately 70 ° C.
  • the operating temperature is therefore set at approximately 90 ° C.
  • FIG. 2 further shows that the inking roller does not have a smooth, but rather a screened surface structure with regularly arranged depressions 75.
  • these depressions are designed as cups which are produced by engraving, for example by laser engraving.
  • the depth of these cells 75 is a few ⁇ m. A range of approximately 8 to 25 ⁇ m appears to be technically sensible, with a well depth of approximately 15 ⁇ m proving particularly advantageous.
  • the diameters of the cups 75 are chosen so that approximately 90 cups / cm are arranged in a regularly distributed manner. In printing technology, this is usually referred to as a 90 screen. However, as studies have shown, this is only a medium value, and satisfactory results are also achieved with grids that are in a range from approximately 60 to 120 cells / cm, which corresponds to grid widths in a range from 0.08 to 0.2 mm .
  • the surface of the inking roller should be as wear-resistant as possible, so that the materials for the surface of the inking roller 72 are both high-strength steel alloys with a copper-plated and subsequently chrome-plated surface, and ceramic materials such as aluminum oxide.
  • FIG. 2 the well structure schematically indicated in FIG. 2 is only one possible embodiment. It would be readily conceivable to also form other raster structures in the peripheral surface of the ink roller 72, for example a dot screen in the form of a dome or pyramid, with the latter in particular having finely distributed, regularly arranged channels in the peripheral surface of the ink roller. However, these channels are preferably not aligned with the surface lines of the roller, but rather are inclined at a certain angle.
  • Such surface structures of the inking roller 72 have the purpose that the depressions fill when the inking roller 72 is immersed in the printing ink which is kept liquid in the tub 71. If, due to the rotation of the ink roller 72 by the doctor blade 73, the carried-away printing ink is then superficially removed, a defined proportion of printing ink remains for the renewed coating of the dye carrier 1 in the depressions.
  • the pressure roller 74 has a surface layer 76.
  • This surface layer is a few mm thick and should be sufficiently wear-resistant at the operating temperature mentioned and should have a defined hardness. Experiments have shown that a Shore hardness range of about 50 to 80 SH, preferably about 70 SH, gives the best results.
  • the pressure roller 74 presses against the ink roller 72 and the dye carrier 1 guided between them with a pressure force P of approximately 500 N. A range of about 250 to 600 N could also be considered for this pressing force P.
  • Electrically conductive silicone rubber can be used as the surface layer of the pressure roller 74.
  • the dye carrier 1 is heated as soon as it comes into the wrapping area with the pressure roller 74, and thus the portion of ink remaining after printing is melted back.
  • the remelted printing ink is squeezed off in the inlet area of the inking roller 72 and the pressure roller 74. As indicated in FIG. 2, there is a certain excess of color in this inlet area, which may run back into the tub 71.
  • the printing ink is released from the depressions 75 of the pressure roller 72 and is distributed in a uniform layer on the dye carrier 1.
  • the dye carrier 1 When the dye carrier 1 is transported further, it cools down, so that the ink layer solidifies. In this state, the dye carrier runs again, as described, into the printing station formed from the pressure roller 5 and the printing comb 6.

Landscapes

  • Ink Jet (AREA)
EP89114577A 1989-08-07 1989-08-07 Dispositif d'encrage pour imprimante thermique par transfert Withdrawn EP0412179A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP89114577A EP0412179A1 (fr) 1989-08-07 1989-08-07 Dispositif d'encrage pour imprimante thermique par transfert

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP89114577A EP0412179A1 (fr) 1989-08-07 1989-08-07 Dispositif d'encrage pour imprimante thermique par transfert

Publications (1)

Publication Number Publication Date
EP0412179A1 true EP0412179A1 (fr) 1991-02-13

Family

ID=8201730

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89114577A Withdrawn EP0412179A1 (fr) 1989-08-07 1989-08-07 Dispositif d'encrage pour imprimante thermique par transfert

Country Status (1)

Country Link
EP (1) EP0412179A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022128929A1 (fr) 2020-12-14 2022-06-23 Armor Module de revêtement pour revêtir une couche mince d'encre sur un ruban
WO2022128946A1 (fr) 2020-12-14 2022-06-23 Armor Appareil d'impression thermique comprenant un refroidisseur
EP4311680A1 (fr) 2022-07-28 2024-01-31 Armor Dispositif de support amovible pour supporter un ruban sans fin

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0029313A2 (fr) * 1979-10-30 1981-05-27 Oki Electric Industry Company, Limited Imprimante thermique

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0029313A2 (fr) * 1979-10-30 1981-05-27 Oki Electric Industry Company, Limited Imprimante thermique

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 10, no. 273 (M-518)(2329) 17 September 1986, & JP-A-61 95961 (Y. NAGAHAMAYA) 14 Mai 1986, *
PATENT ABSTRACTS OF JAPAN vol. 13, no. 305 (M-849)(3653) 13 Juli 1989, & JP-A-1 95086 (K. SHIMADA) 13 April 1989, *
PATENT ABSTRACTS OF JAPAN vol. 4, no. 111 (M-25)(593) 09 August 1980, & JP-A-55 69489 (Y. MORITA) 26 Mai 1980, *
PATENT ABSTRACTS OF JAPAN vol. 4, no. 136 (M-33)(618) 24 September 1980, & JP-A-55 91692 (Y. MORITA) 11 Juli 1980, *
PATENT ABSTRACTS OF JAPAN vol. 7, no. 128 (M-220)(1273) 03 Juni 1983, & JP-A-58 45968 (Y. TOUDOU) 17 März 1983, *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022128929A1 (fr) 2020-12-14 2022-06-23 Armor Module de revêtement pour revêtir une couche mince d'encre sur un ruban
WO2022128946A1 (fr) 2020-12-14 2022-06-23 Armor Appareil d'impression thermique comprenant un refroidisseur
CN116981573A (zh) * 2020-12-14 2023-10-31 阿尔莫 用于在带材上涂布油墨薄层的涂布模块
US12017464B2 (en) 2020-12-14 2024-06-25 Armor Thermal printing apparatus comprising a cooler
US12064982B2 (en) 2020-12-14 2024-08-20 Armor Coating module for coating a thin layer of ink on a ribbon
EP4311680A1 (fr) 2022-07-28 2024-01-31 Armor Dispositif de support amovible pour supporter un ruban sans fin

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Owner name: SIEMENS NIXDORF INFORMATIONSSYSTEME AG

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