DE2365504A1 - THERMAL PRINTER - Google Patents

Description

- BüHLING - K

INSIDE

Patent attorneys:

Dipl.-Ing. Tiedtke Dipl.-Chem. Bühling Dipl.-Ing. Chins

8 Munich 2

Bavariaring 4, PO Box 202403

Tel .: (089) 539653-56 Telex: 524845 tipat cable address: Germaniapatent Munich

Munich, November 14, 1974

B S317

Canon Kabushiki Kaisha
Tokyo, Japan

Thermal printer

The invention relates to a thermal printer for printing letters, numerals and the like characters on a recording material using a thermal Head with heat generating element that selectively activates and doing multi-color printing on a heat-sensitive Act on recording material.

The invention is based on the object of a thermal Printer specified in the preamble of claim 1 in more detail Way of creating the various types of information

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Iation hardening printed out in different colors.

According to the invention, this task is carried out with the mark of claim 1 specified means solved.

The invention is explained below with reference to the description of exemplary embodiments explained in more detail with reference to the drawing.

Figures 1, 2 and 3 show conventional thermal printers;

FIG. 4 shows an embodiment according to the invention;

FIG. 5 shows one of the thermal heads which can be used according to the invention; '

Figure 6 shows an example of printing with the thermal head shown in Figure 5;

FIG. 7 shows a further applicable according to the invention thermal head;

Figure 8 shows another embodiment of the thermal Printer using the thermal head shown in FIG ;

Figure 9 is a sectional view showing the pushed-on portion of the embodiment of Figure 8;

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Figure Io shows yet another embodiment of the

printer according to the invention; \

Figure 11 is a longitudinal section of the embodiment.

according to Figure Io; ! "■

Figure 12 shows another embodiment of the '.,' * · ' Invention; , * "·· __ ■ · _

Figure 13 shows another embodiment of a Feed device with a rubber roller;

FIG. 1h shows a further embodiment which has a heater which supplies heat to heat-sensitive paper;

Figure 15 shows a thermosensitive recording medium which allows and disables multicolor color recording heat-sensitive layers I and II on a base layer III consists;

Figure 16 shows the relationship between the color forming temperature and the color formation density of the heat-sensitive layers I and II.

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Figures 1, 2 and 3 show conventional printers. \ According to Figs. 1 and 2, the printing takes place in, for example a state takes place in which "a thermal head-1 by means of a spring under a compressive force in the range of 500 g to 1 kg over a recording material 2 in press contact with an elastic buffer rail 3, for example made of rubber or felt. The thermal head. 1 stands at Printing with the recording material 2 by the elastic force of the elastic buffer rail 3 in close contact, however, a solenoid U must be energized in order to lift the head 1 from the recording material 2 when this is after Completion of printing is moved forward by one line. The reason is that a recording material feed roller 5 is arranged so that it advances the recording material 2, but it is not able to when the press contact is maintained between the head 1 and the recording material 2, so that then Inefficiencies, such as deformations and defects in the 'print distances, arise. To solve these points is a method has already been proposed in which the recording material 2 is attracted by a pulling roller 6,

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Vorscimbwalze Io has a small diameter, the Pressing force can be kept lower, so that ', the device very small dimensions are obtained and even sufficient by using a pulse motor 12 of an extremely small, type can be operated. In addition, can also

the spring 11 can be very small. J

I j

Figures 7, 8 and 9 show other exemplary embodiments, in which a feed roller Io is intermittent by means of a pulse motor 12 at high speed is driven while printing in one state is carried out in which a tape-like recording material 14 by means of a spring 11 with the head 17 in press contact is held; this device is for typewriters of smaller type, a printer for counting machines and the like extremely suitable. In the case where a thermal head 17 that prints dotted lines is used as shown in Fig. 9 is the printing area a dotted line 17 * small, so that even then a sufficient Contact area for printing is guaranteed when a small diameter roller is used.

. ι

Fig. Io shows a further embodiment of the

Invention in which the device is kept small by placing the pulse motor 12 shown in FIG. 4 within the Feed roller Io is housed so that its interior

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is exploited. The torque of shaft 12 ^! of the pulse motor is transmitted to a gear 2o, with which wires 7 and 9 are wound and unwound. In the middle portion between the wires 7 and 9, as shown in Fig. 12, there is mounted a print head 13 which is moved by the rotation of the motor to perform one line printing. : ·

When the motor rotates in the opposite direction, the gear 2o is rotated in the opposite direction as it does mit'dem arrow is shown, wherein the wire 9 is unwound and the head returns to its original position. When a command signal PFD to feed the recording material When an electromagnetic clutch 22 is reached, the shaft of the gear 2o becomes the shaft of a gear 21 brought into engagement so that the gear 21 rotates. When the gear wheel 21 is rotated, a gear wheel 23 rotates at the same time, that combs with this. The gear wheel 2 3 is attached to a feed device 3o for the recording material which, as shown in Fig. 11 is rotatably mounted outside the motor so that it is also rotated and that The recording material is advanced by the frictional force of the rubber roller Io mounted on the advancing device 3o is what causes the paper feed. When the feed command signal PFD on the electromagnetic clutch 22 is switched off and disappears, the clutch 22 is opened again, so that the gear 2o out of engagement with the gear 21 and the paper feed is stopped.

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■ - - 2385504

A maximum amount of "letters or numbers" in a Line kaim through, ^ ee-igaete setting the width of the Vorsibbefehlssigna-is FFD are set while the sequence-r printing a line ,. Feed printing one line - «· .- systematically by" setting the EiB- ' sentence: of the signal at an appropriate time after completion of printing a line; can be determined.

All moving parts of this printer, like the ones for intermittent advancement of the print head along the "print line, to the oBea described materials and the like are driven by a drive source and are arranged within the feed device 3o » so that the entire facility is kept very small can be.

In Fig. 11, reference numerals denote 26, 27 and Bearings, of which the 2S- bearing is on a motor support shaft 21 is mounted and carries the feed device 3o rotatably. - " Camp 2? is for one rotation of the drive shaft 12 * des Motor 12 and the feed device 3o provided while the bearing 28 the feed device. 3o rotatable in a solid wall_ -

At the inventions. Construction according to Fig. Io is the Burchmessex »dar- Simaai roller 12 with regard to the Pressure contact area of the thermal head sufficiently large,

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■■ Ό ti

- Io -

so that the printing device ensures that the Fönmige thermal head 13 is placed in plane contact. Furthermore, in this case, more planning is needed to achieve exKer * ' Touching a vor chube xnrx chtting used: which is a polygonal Rubber roller "32" as shown in FIG is. This polygon feed device is one-story manufactured and therefore has an essentially flat printing surface, which is suitable for such a thermal head » which is difficult to form with a curvature «scans, is extremely suitable.

Also dotted-Therraoköpfej are as Jews, figures are 5 and 8 "suitable.

In the construction shown in Fig. 11, something becomes

Heat is radiated when the engine 12 rotates. This lame is held in the Gunapi cylinder Io . , transferred to the recording material, for example wärmeeinpfindliches paper, which may be heated to an extent that no Farbbildurag _t is generated. Therefore, if a preheating system is built into the thermal printer, the current to be transmitted to the tkenExschera head for printing will be decreased, thereby increasing the life of the head. Further, it is possible to eliminate indistinct printing, limitation of the printing speed to a maximum value due to a delay in the response of the recording material, and the like. Or, as shown in Fig. 14, heat-

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delicate paper or a positive exothermic one Means provided on the thermal head. In Fig. IU reference numeral 33 denotes a thermal head, various types of thermal heads other than those in the

Above described can be used. The reference number 34 denotes a line to Flow of a drive current selectively each heat generating element applied; the reference number 35 denotes a temperature control circuit for the formation of a preheating, via a line 36 a preheating flow for heating of the thermal head 33 to an extent that it cannot print yet. Below are various other devices for preheating the thermal Head 33 considered. For example, using an integral technique, a heat generating wire can be placed near the Heat generating element of the head can be embedded or inserted or one lets a current of half or one Third of the drive current for normal printing flow into each heat generating element in the same size. The reference numeral 37 denotes a control device which detects the existing temperature of the head 33 and on the Control circuit 35 feeds back and controls the preheating control current from line 36. In this way, an undesirable Printing from an excessively heated head 3

prevents and achieves a room temperature in its environment, which continuously guarantees continuously optimal printing.

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perform. Reference numeral 38 denotes an exemplary embodiment of a heat-emitting device made of insulating material for heating a thermosensitive recording material to the extent that no color formation is generated.

Recently, a good quality thermosensitive recording material which, when exposed to a given heat, does not show discoloration and maintains the state without the application of heat, has been produced. • As a result, the same effect as that described above can be obtained even if the recording material is preheated. The reference number Uo denotes a line for flowing a preheating current and 41 a line for feedback of a detector current from a temperature sensor 39 to the control circuit 35. The reference number Uo ¹ denotes a heat-generating wire. The insulating part 38 is best immediately before the point where the printing by the. Head 33 takes place, arranged. The optimal place is the place. on the side of the recording material opposite the head 3 3. "With such a preheating construction, multicolor printing making use of a multicolor recording material can easily be included. By this is meant multicolor printing on a multicolor, color-forming thermosensitive recording material having a thermosensitive layer I which is at a temperature T forms a color, and a heat-sensitive layer II which _{forms a color at a temperature T 2} (FIG. 16), each layer being applied to a base material III; this

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multi-color printing will be described below with reference to FIG. The heat sensitive layer ί will for ordinary printing with the print head 3 3 (e.g. black) used while the heat-sensitive Layers II and I 'can be used for printing a different color (e.g. red). In this case the color-forming temperature of the heat-sensitive layer II is higher than that of the heat-sensitive layer I. (Fig.16) j so that it is necessary to provide the drive current for the Raise head. As described above, the thermal head has a limit by a maximum allowable drive current, so that it is impossible to limit the current indefinitely

raise. In this case, multi-colored printing can be used be carried out in such a way that an increased current is given to the head 3 3 by the control circuit without this has a harmful effect on the head. When on the insulating part. 38 or the head 33 is given the increased current, the heat-sensitive layers 11 and II respond, whereby the formation of mixed coloration of the heat-sensitive layers I and II appears. Accordingly, there will be color formation different from that obtained from the heat-sensitive layer I alone, so that a favorable application effect is achieved. The clarity and the high speed of pressing are through Heating the heat-sensitive layer II with the relative high color formation temperature from the base material III favorably influenced.

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As described above, because of the preheating structure " noticeably reduced, so that the multicolor printing can be easily done by just controlling a current to the Head can be carried out without the head having to be switched off when the maximum permissible current is determined is used to keep the heat-sensitive layer that forms the color at the highest temperature *

Alternatively, it can be constructed so that a current flows from the control circuit 35 only in the event that the multicolored Printing is carried out without normally 'a preheating current to the insulating part 38 or dem.Kopf 33 flows.

The control circuit 35 also takes on the function of discriminating the print patterns of the different colors. and control. In the event that the printer according to the invention is used, for example, on an electronic counter finds, different color formations can be controlled in such a way that the printing of ordinary number processing processes, such as function numbers (characters), numbers to be processed or the like in black, printing of calculation results in green, printing of an overflow in red, printing of polling memories in blue, and so on will. ■■

According to the illustration shown in FIG. 14, the A printer using a thermal head as described above is formed as a preheating structure, whereby

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the permanent heat stress as a result of the rapid change the temperature (current change) is reduced, so that the life of the print head increases, the printing speed as a result of performing printing with less temperature change, and printing sharpness increases is improved without the printing becoming uneven, since the temperature gradient on the recording material is not is great.

Furthermore, if an execution applies, like them As shown in Fig. 11, a printer simple in construction and extremely small can be used.

As described above, the thermal printer of the present invention has various properties as follows are listed:

1. The printer can be kept small because there are no elastic buffer rail 3, no solenoid 4 and the like. Provided are.

2. There is no irregularity in the paper feed distance because the thermal head and the feed roller are over the recording material are arranged opposite one another with press contact. Both in forward and In the reverse direction, a correct advance can be effected, so that the letters or digits once printed easily can be removed by backward feed.

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3. To insert recording material this " can only be inserted between the feed roller and the thermal head, which is very simple.

H. Recorded letters or numbers are never

ι · i

hidden behind pinch rollers. !

5. When a dotted line thermal head as shown in Fig. 7 is used, a small pulse motor can be used, making an extremely small portable printer results.

-6. A preheating construction can easily be applied.

The invention thus provides a thermal printer for printing a recording material "; created with Tvpen having a dotted line thermal head. Printing takes place in a state in which the thermal head in pressing contact over the recording material stands with a feed roller for the recording material, wherein the thermal head is kept in pressing contact with the feed roller even when the recording material is advanced by one line after printing is complete. To reduce the required electrical current, a Preheating construction must be built in.

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Claims (8)

Claims l.j thermal printer with a thermal head with Heat generating elements for printing on a heat-sensitive recording material by selective activation these elements provided for multicolor printing and with a device for advancing the recording material, characterized by a control circuit on an electronic computer for generating a signal for selective Activation of the elements of the thermal head (33), soft Control circuit distinguishes between it supplied information and then the signal to carry out the multicolored Pressing generated on the basis of this distinction. 2. Thermal printer according to claim 1, characterized in that that the control circuit is a device which distinguishes between calculated values, an overflow or the like and printing the calculation values, overflow and the like in different colors. 5098 18/0674 3. Thermal printer according to claim 1 or 2, characterized in that a preheating device (38) for feeding of heat is provided to the recording material, which for Carrying out the pressing is not yet sufficient and that the preheating device is arranged in the vicinity of the recording material is. ~ 4. Thermal printer according to claim 3, characterized in that a detector device (39) for detection the heating insufficient for printing is arranged in the vicinity of the preheating device (38) and a device (35) is provided for controlling the activation current liquid supplied to the thermal head (33). 5. Thermal printer according to claim 3 or 4, characterized in that the preheating device (38) in the feed device (lo) is housed. 6. Thermal printer according to claim 3, characterized in that that the preheater is provided in the thermal head (33). 5098 18/0674 7. Thermal printer according to claim 4, characterized in that the detector device (39) in the feed device (lo) is housed for the recording material. 8. Thermal printer according to claim 4, characterized in that that the detector device is provided in the thermal head (33). 09818/0 674 lee ⁹⁰ · ♦ rs e ι te