EP0187196B1 - Thermotransferdrucker - Google Patents

Thermotransferdrucker Download PDF

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Publication number
EP0187196B1
EP0187196B1 EP85110877A EP85110877A EP0187196B1 EP 0187196 B1 EP0187196 B1 EP 0187196B1 EP 85110877 A EP85110877 A EP 85110877A EP 85110877 A EP85110877 A EP 85110877A EP 0187196 B1 EP0187196 B1 EP 0187196B1
Authority
EP
European Patent Office
Prior art keywords
platen
thermal transfer
transfer printer
timing pulley
buffer cylinder
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
EP85110877A
Other languages
English (en)
French (fr)
Other versions
EP0187196A1 (de
Inventor
Yoji Okazaki
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.)
Toshiba Corp
Original Assignee
Toshiba Corp
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 Toshiba Corp filed Critical Toshiba Corp
Publication of EP0187196A1 publication Critical patent/EP0187196A1/de
Application granted granted Critical
Publication of EP0187196B1 publication Critical patent/EP0187196B1/de
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
    • 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
    • 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
    • B41J11/02—Platens
    • B41J11/04—Roller platens
    • 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
    • B41J11/24—Detents, brakes, or couplings for feed rollers or platens

Definitions

  • the present invention relates to a thermal transfer printer according to the preamble of claim 1.
  • Such a printer is known from EP-A-0 098 033.
  • the thermal transfer printer includes a step motor 10 which is arranged to turn a platen 14 intermittently through a timing pulley 12 and a timing belt 18 that is wound round a timing pulley 16 mounted on the platen 14.
  • the upper running portion of the timing belt 18 is set to be the tension side of the belt.
  • an ink ribbon 20 is arranged to be advanced by a ribbon-feeding motor 21 and by a conveyor roller 22 for winding the ribbon to an ink ribbon reel 24 by passing directly underneath the platen 14. With the ink ribbon in between, a line-form thermal head 26 is arranged facing the platen 14.
  • the recording paper 28 is fed from the paper supply cassette by a paper supply roller 32, runs between the platen 14 and the ink ribbon 20 through guide plates 33 and a guide roller 35, and is printed on by the thermal head 26 after running round the platen 14 for about one half of its circumference.
  • the recording paper 28 which has been printed is sent out to the paper removal tray 36 by a forwarding roller 34.
  • the thermal transfer printer further includes a power supply unit 37 for driving the step motor and a controller 38 for controlling the turning operation and the like of the platen 14.
  • the shaft 40 of the platen 14 is supported by the bearings 44 prepared on the frame 42 (see Fig. 3).
  • the major scanning is carried out by the thermal head 26 while the minor scanning is carried out by the intermittent turning of the platen 14.
  • the ink ribbon 20 is brought to a direct contact with the recording paper 28 which is wound round the platen 14, and the printing is accomplished by thermal transcription with the thermal head 26.
  • the thermal head 26 is pressed against the platen 14 with a force of several kg-weight so that there is required a large torque in order to turn the platen 14 intermittently.
  • On the timing belt there is applied an intermittent tension due to the intermittent drive of the platen 14.
  • Owing to the intermittent tension and the friction load on the thermal head 26 there is applied a force in the radial direction of the shaft of the platen 40 which varies periodically. The force is transmitted to the frame 42 and generates a noise by causing the frame to vibrate.
  • a shock-absorbing drive sprocket for engaging a drive belt is known from US-A-4486183. It comprises two relatively rotatable members having radially extending lugs separated by elastomeric material having embedded reinforcement fibres. Thus the construction is relatively complicated and expensive to manufacture.
  • An object of the present invention is to provide a thermal transfer printer of simple construction which produces low noise and yet possesses high printing accuracy.
  • Another object of the present invention is to provide a thermal transfer printer which is adapted in a simple manner for suppressing the generation of noise caused by the intermittent turning of the platen.
  • a thermal transfer printer for thermally recording information on a recording paper, including a platen for winding the recording paper, a thermal head for thermally recording information on the recording paper, a stepping motor for intermittently turning said platen via a timing belt, and a timing pulley with wound timing belt installed at said platen for transmitting the driving power from said stepping motor to said platen, characterised in that:
  • FIGs. 4 and 5 there is shown the platen section of a thermal transfer printer embodying the present invention.
  • the thermal transfer printer includes a timing pulley 50 constructed by a plain cylindrical inner ring 50a which is fitted and fixed directly to the shaft 40 of the platen, and an outer ring 50c, with teeth on its outer peripheral surface, which is fitted to the inner ring 50a via an elastic buffer cylinder 50b.
  • the force that is exerted on the platen in its radial direction by the timing belt 18 at the time of intermittent turning of the timing pulley 50 is mollified by the buffer cylinder 50b.
  • Fig. 6 there is illustrated a vibration model forthe radial direction of the shaft of the platen in the thermal transfer printer of the present invention shown in Fig. 4, in Fig. 7A is illustrated a vibration model for the radial direction of the shaft of the platen for the prior art thermal transfer printer in which no use is made of a buffer, and in Fig.
  • FIG. 7B is illustrated a vibration model for the radial direction of the saft of the platen for the prior art thermal transfer printer in which a buffer is inserted between the bearings and the frame.
  • Ma represents the mass of the outer ring 50c of the timing pulley on the platen side
  • m a is the sum of the masses of the platen 14 and the inner ring 50a of the timing pulley 50
  • Ma1 is the mass of the timing pulley 50
  • ma1 is the mass of the platen 14
  • K and K1 represent the spring constant
  • F represents the external force that acts on the timing pulley 50 due to the intermittent tension on the timing belt 18.
  • the external force F is transmitted to the frame 42 as is because of the rigid joining of the various elements such as the timing pulley 50 and the shaft 40 of the platen.
  • the timing pulley 50 and the platen constitute a system of forced vibration with one degree of freedom. That the transmissibility of the external force F to the frame 42 in this case will be less than unity for the range of frequency which is above the square root of two times the resonant frequency
  • the transmissibility of the external force F becomes less than unity for the range of frequency which is above square root of two times the resonance frequency 1/2rt K/Ma, so that it becomes possible to reduce the generation of noise due to the external force F in the radial direction of the shaft of the platen 40. It is to be noted that what is displaced due to the intermittent tension on the timing belt 18 is the outer ring 50c alone of the timing pulley 50. Since there will be created no relative displacement between the platen 14 and the thermal head 26, no reduction in the printing accuracy will be generated.
  • Fig. 8 are compared the results of measurement on the acoustic power level for the prior art thermal transfer printer shown in Fig. 7A and for the thermal transfer printer in accordance with the present invention. From the figure, it will be seen that a reduction of 5 dB in the acoustic power level of the noise can be achieved by the use of the device of the present invention.
  • FIG. 9 there is illustrated a second embodiment of the thermal transfer printer in accordance with the present invention.
  • This embodiment shows an example in which the present invention is applied to the case where a high accuracy in the direction of paper feeding is required for carrying out superposed impressions as for the color printing.
  • the buffer cylinder 50b there are created on the buffer cylinder 50b a plurality of equally spaced radial notches 54 that extend from its outer periphery toward the center, and on the inner periphery of the outer ring 50c there are fixed wings 56, consisting of projections that fit the notches 54, that are made of a material, such as metal or plastic, with elastic modulus greater than that for the elastic body constituting the buffer cylinder 50b.
  • the torsional spring constant k of a cylindrical anti-vibration rubber piece is given by the following expression.
  • G is the shearing modulus
  • I is the axial length of the cylinder
  • r 1 and r 2 represent the inner and outer radius, respectively.
  • the spring constant in the radial direction of the buffer cylinder 50b can be represented as the sum of spring constant due to shearing stress and the spring constant due to compression and tension.
  • the spring constant due to shearing is small compared with that due to compression and tension so that the spring constant in the radial direction of the cylindrical anti-vibration rubber piece is dominated by the spring constant due to compression and tension. Therefore, even when the torsional spring constant of the buffer cylinder 50b is increased by the wings 56, the increase in the spring constant in the radial direction will not be appreciable. As a result, it becomes possible to suppress the transmissibility vibrations to the platen 14 and the shaft of the platen 40, as well as to secure the accuracy in the direction of paper feeding.
  • FIG. 11 there is shown a third embodiment of the thermal transfer printer in accordance with the present invention.
  • this embodiment there are provided notches 54a, which are similar to the previous notches 54, on the inner periphery of the buffer cylinder 50b, and on the inner ring 50a of the timing pulley 50 there are provided wings 56a which are similar to the previous wings 56.
  • notches 54a which are similar to the previous notches 54
  • wings 56a which are similar to the previous wings 56.
  • FIG. 12 there is shown a fourth embodiment of the thermal transfer printer in accordance with the present invention.
  • wings 56a on the inner ring 50a of the timing pulley and wings 58 on the outer ring 50c of the timing pulley are installed with their respective positions alternating.
  • wings 56a on the inner ring 50a of the timing pulley and wings 58 on the outer ring 50c of the timing pulley are installed with their respective positions alternating.
  • FIG. 13 there is shown a fifth embodiment of the thermal transfer printer in accordance with the present invention.
  • cylindrical projections 60 along the inner periphery of the outer ring 50c of the timing pulley. These projections 60 are made of a material with elastic modulus which is greater than that of the elastic body that constitutes the buffer cylinder 50b. For this embodiment, too, effects similar to those of the embodiments described in the foregoing can be obtained.
  • a thermal transfer printer in accordance with the present invention can suppress the generation of the noise created by the intermittent turning of the platen, without reducing the printing accuracy to any degree. Therefore, it can prevent the increase in noise within an office accompanying the spread of office automation.

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  • Handling Of Sheets (AREA)

Claims (7)

1. Ein Thermotransferdrucker zum thermischen Aufzeichnen von Informationen auf einem Aufzeichnungspapier, mit einer Walze (14) zum Wickeln des Aufzeichnungspapieres, einem Thermokopf (26) zum thermischen Aufzeichnen von Informationen auf dem Aufzeichnungspapier, einem Schrittmotor (10) zum schrittweisen Drehen der Walze (14) über einen Synchronriemen (18) und einer Synchronriemenscheibe (50), die mit dem herumgeführten Synchronriemen (18) an der Walze (14) zum Übertragen der Antriebsenergie vom Schrittmotor (10) zur Walze (14) angeordnet ist, dadurch gekennzeichnet, daß die Synchronriemenscheibe (50) einen inneren Ring (50a), einen äußeren Ring (50c) und einen Pufferzylinder (50b) aufweist, der zwischen dem inneren und äußeren Ring .eingesetzt ist.
2. Thermotransferdrucker nach Anspruch 1, bei welchem der Thermokopf (26) fest an dem Rahmen angeordnet ist, der die Walze trägt.
3. Thermotransferdrucker nach Anspruch 1 oder 2, bei welchem der Pufferzylinder (50b) einen elastischen Körper aufweist.
4. Thermodrucker nach Anspruch 3, bei welchem eine Mehrzahl von vorspringenden Teilen angeordnet sind, um von dem inneren Umfang des äußeren Ringes (50c) der Synchronriemenscheibe (50) in radialer Richtung der Synchronriemenscheibe vorzuspringen, um in Einkerbungen einzugreifen, die im Pufferzylinder (50b) vorgesehen sind, und wobei die vorspringenden Teile aus einem Material mit einem Elastizitätsmodul hergestellt sind, der größer ist, als derjenige des elastischen Körpers, der den Pufferzylinder bildet.
5. Thermotransferdrucker nach Anspruch 3, bei welchem eine Mehrzahl von vorspringenden Teilen vorgesehen sind, die vom äußeren Umfang des inneren Ringes (50a) der Synchronriemenscheibe (50) in radialer Richtung der Synchronriemenscheibe (50) vorspringen, um in Einkerbungen einzugreifen, die im Pufferzylinder (50b) vorgesehen sind, wobei die vorspringenden Teile aus einem Material mit einem Elastizitätsmodul bestehen, welcher größer ist als derjenige des elastischen Körpers, der den Pufferzylinder bildet.
6. Thermotransferdrucker nach Anspruch 3, bei welchem eine Mehrzahl von vorspringenden Teilen abwechselnd vorgesehen sind, um von dem inneren Umfang des äußeren Ringes (50c) und dem äußeren Umfang des inneren Ringes (50a) der Synchronriemenscheibe in radialer Richtung der Synchronriemenscheibe (50) vorzuspringen, um in Einkerbungen einzugreifen, die im Pufferzylinder (50b) vorgesehen sind, und wobei die vorspringenden Teile aus einem Material mit einem Elastizitätsmodul bestehen, welcher größer ist als derjenige des elastischen Körpers, der den Pufferzylinder bildet.
7. Thermotransferdrucker nach Anspruch 3, bei welchem eine Mehrzahl von vorspringenden Teilen ferner entlang dem inneren Umfang des äußeren Ringes (50c) der Synchronriemenscheibe (50) vorgesehen sind, und wobei die vorspringenden Teile aus einem Material mit einem Elastizitätsmodul bestehen, der größer ist als derjenige des elastischen Körpers, der den Pufferzylinder bildet.
EP85110877A 1985-01-07 1985-08-29 Thermotransferdrucker Expired EP0187196B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP60000611A JPS61160264A (ja) 1985-01-07 1985-01-07 熱転写プリンタ
JP60611/85 1985-01-07

Publications (2)

Publication Number Publication Date
EP0187196A1 EP0187196A1 (de) 1986-07-16
EP0187196B1 true EP0187196B1 (de) 1989-06-14

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ID=11478522

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Application Number Title Priority Date Filing Date
EP85110877A Expired EP0187196B1 (de) 1985-01-07 1985-08-29 Thermotransferdrucker

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EP (1) EP0187196B1 (de)
JP (1) JPS61160264A (de)
DE (1) DE3571007D1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5092690A (en) * 1989-05-09 1992-03-03 Texas Instruments Incorporated Portable printer
CN111546765B (zh) * 2020-05-29 2024-09-10 浙江思迈拓科技有限公司 一种笔壳热烫机

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1018800A (en) * 1975-10-03 1977-10-11 Platt Saco Lowell Corporation Composite resilient pulley wheel
US4366609A (en) * 1979-09-17 1983-01-04 Dayco Corporation Composite pulley and method for making
US4486183A (en) * 1980-06-30 1984-12-04 The Gates Rubber Company Torsionally elastic power transmitting device and drive
JPS591274A (ja) * 1982-06-29 1984-01-06 Toshiba Corp 熱転写記録装置

Also Published As

Publication number Publication date
DE3571007D1 (en) 1989-07-20
EP0187196A1 (de) 1986-07-16
JPS61160264A (ja) 1986-07-19

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