DE7501004U - DEVICE FOR GENERATING TIME SIGNALS IN A DATA PRINTER - Google Patents

Description

Patent Attorneys i ι wawbri .::

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Difl.-Ing. H.Weickmann, Dipl.-Phys. Dr. K. Fincke D1PL.-ING. F. A / Weickmann, Dipl.-Chem. B. Huber

8 MUNICH 86, DEN

PO Box 860 820

MDHLSTRASSE 22, CALL NUMBER 98 3921/22

Dataproducts Corporation

6219 De Soto Avenue

Woodland Kills, California 91J> 6h, AjSA

Device for generating time signals in a data printer

The invention relates to a device for generating time signals in a data printer, for example works with pressure, with which characters be printed on a recording medium by placing it against characters on a movable Character tape or pen mark carrier beaten will.

In a known high-speed printer, there is the printing mechanism from a type carrier, which can be designed as a band and an arrangement of different characters to be printed. Printing takes place by moving this arrangement of characters or of the characters relative to a printing station on which a recording medium is arranged. The characters are selective on this recording medium * by means of actuating elements such as pressure hammer !! brought up. The hammers are evenly spaced to each other along the line of movement of the

Characters arranged. They are designed so that they are individually actuated by actuators can be that the recording medium is hit against the characters while move them along the print line. An example of such a printer is shown in U.S. Patent 5,303,775 known.

The distance between the hammers is - ^ typically less than the space between characters on the moving belt. In the aforementioned patent, the character spacing is, in the following also referred to as character pitch, 3/2 of the hammer distance or the hammer division. Such a relationship leads to a mechanical operation in which the Characters aligned in the manner of a sub-cycle with the characters facing every third print hammer during each sub-cycle. Three sub-cycles are required to be consecutive Align characters on the tape to one and the same chamber. To get a real pressure precise timing signals for actuation are to be ensured only those hammers are required to which the characters to be printed are aimed.

So far, relatively complicated arrangements have been used to generate the time signals. Some of these arrangements use timing gears that are mechanical with the moving belt or its moving mechanism are coupled. However, these arrangements will cause small differences in character spacing on the tape not fair, but they are unavoidable and are often in the order of a few thousandths of a centimeter.

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The known arrangements also do not generate such time signals in which the distance error occurs in a large number characters lying next to one another are averaged in such a way that they approach zero. Hence the generated pressure is not satisfactory.

It is the object of the invention to provide a device for generating precise time signals. ¹ e to be specified in a printer in which a character zv ^ is moved past the printing station, for example. Such time signals are intended to enable the chamber to be controlled without a direct mechanical coupling with the character carrier or its drive mechanism being necessary. The mean spacing error of all characters on the character carrier should be kept to a minimum.

To solve this problem, the invention creates a system in which the time signals are phase-etched Control loop (PLL) are generated in which the frequency with which the characters are moved on the Belt run past an evaluation station, multiplied v.'ird.The factor of this "multiplication is on the relationship between font and character division Hammer pitch related. The movement of the characters past the evaluation station is used to generate control signals that of the control loop are fed. With a ratio of character division to compartment division with a value XA * where X and Y are integers and X is greater than Y, the control loop contains an X-level ring counter, of the X successive time signals at its X outputs during the mean running time of a every character generated by the evaluation station.

* The time signals on each output line are used for control a different hammer group, each group contains every X-th hammer of the hammer arrangement.

The trainings and features of the invention are described below with reference to an exemplary embodiment shown in the figures described. Show it:

Fig. 1 is a schematic representation of a printer in which the invention is applied,

FIG. 2 is a diagram of hammers and characters in FIG
different orientations,

3 shows an Elock diagram of a device according to the invention,

Fig. 4 is a partial perspective view of a Character tape,

Fig. 5 is a more detailed block diagram of an embodiment of the invention and

FIG. 6 shows a representation of signal trains for explaining the exemplary embodiment shown in FIG.

Referring to Fig. 1, there is shown a printer in which the invention can be used. A belt 10 is guided on two drive rollers 11 and 12 which can be rotated by a motor M. The direction of movement of the band ι is shown by arrows 1J> . The band carries a number of character elements F1 to FN, each of which
should have a character on its face.
The designations F1 to FN can therefore be viewed as characters. They are distributed as evenly as possible on the belt. However, there are changes in spacing between adjacent characters in the
Order of magnitude -of a few thousandths of a centimeter-

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envious. The distance between the characters is also referred to as the character pitch P.

The tape and the characters move at a substantially constant speed across a recording medium 15 and an ink ribbon 16 of known type. Several print hammer Kl, K2, YQ, etc. of the line of movement of the characters with 2leichmä3igera are spaced from each other longitudinally arranged. The distance between the chambers or the division between the chambers is called rait P. The hammers are constructed so that they are individually controlled by actuators and each produce on Z-aitpurikt & n characters when aligned they s: nd "Sccnit will therefore each printed a character on the recording medium 15 in Figure 1 shows a... Arrow 13 the hammer movement in the direction of impact to the characters.

The person skilled in the art knows: that the number of characters in the sequence present on the tape, which are simultaneously aligned with the chamber, on the ratio the character pitch P for the hammer pitch P. depends. Typically P> P. This can best be explained in connection with Fig. 2, where in a Line a the hammers H1 to H9 with a division P. of 2.5 mm are shown. In line b, the characters Fl to F7 are shown with a pitch P of 3.2 mm, where the small script Fl on the hammer St. is aligned. In Fig. 2, the character movement is from right to left. The division ratio is 5/4.

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With such an arrangement, every fourth letter is on at every aligned position or escape point aligned every fifth hammer. As can be seen from FIG. 2, the characters are when aligned from Fl to Hl F5, F9, PI ?, Fl5 etc /. on the hammers Ho, HIl, Ηΐβ, H21 etc. aligned. When the tape is moved and so the next escape point is reached, as shown in the cable c, the Hänraer E2, H7, Hl2 etc. to the characters F27 Fo, FlO, Fl4 etc. aligned. The next hammer and character alignment occurs when H ^, Ηδ, H13 etc. on F3, F7, FlI etc. are aligned as shown in line d is shown. Lines e through g show three subsequent orientations of different hammers on different ones Characters.

It can thus be seen that for a division ratio of 5/4, every fifth Hanir.er is aligned with every fourth character during each alignment state. For the present exemplary embodiment, when the tape is moved by a fifth of the character spacing F, another Haramer group is aligned with different characters. Thus, the Hanauers can be seen as divided into five groups, consisting of the Harzers Hl, Ko, HlI etc., K2, KJ, Hl2 etc., H3, Hc, Hip etc., H4, K9, Kl ² »etc. and order H5j HlO, Hl5 etc. Each group is aligned with characters during an alignment position.

Beirr, Betrieb v; ird every Hamner group regardless of the Ha.r.r.ierbev.-esun.sszeit and other delays Time signal supplied when the group is aligned with the characters of the country. V'elche the hammers within

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actually activated in the group depends, of course, on the characters that are aimed at them, scv.-ie of which characters to print out in each case are. The storage and use of the information to be printed out is ensured by the above-mentioned patent specification known. All the circuits required to operate the printer are shown in Fi5. 1 represented by a block 20, which includes printer control. In the following ■ only that part of the circuit is described which the Time signals generated.

The basic principles of the operation of a device according to the invention are explained with reference to FIG. 3, which a front portion of the belt 10 shows. A perspective illustration of the hinge part is also shown in FIG. 4. The belt 10 carries metallic bodies 30, which over the Width of the band 10 run. An alphanumeric character is on the face of each body engraved, which faces the hammer row when operating. The bodies 30 are as constant as possible Distributed at intervals on the belt. Some small differences in distance between adjacent bodies, however, are unavoidable even if the middle The distances of all bodies on the belt are constant. If there is one character on each body is, then the mean interbody spacing agrees with the character pitch P, which is 3.2 mm in the illustrated embodiment.

In Fig. 3 is an electromagnetic sensor or scanner 35, which is arranged at a distance from the bodies 30. When the tape is in the direction of the arrow 13 moves, the scanner generates for each scanned Body a signal. The frequency of these signals

is denoted by fl. It depends on the belt speed and from the character pitch P. If the belt has a speed of 4.1 in / see and a average character pitch of 3.2 nm provided is, then the frequency fl has the "value 1280. The mean period between the signals or pulses or the The pulse period is therefore 1/1280 = 0.7δ ms.

If the actual character pitch P for all \ characters is exactly 3 * 2 now, ie if all bodies

] have a distance of exactly 3 * 2 mm to each other, so can

each pulse delivered by your scanner by means of a Frequency multiplier Tachers to generate five signals

: lead during each pulse period of 0.78 ms.

Because small differences in distance between adjacent However, bodies are unavoidable, the pulses of the scanner cannot directly generate the required Time si. ^ Nals serve.

This problem is avoided by the circuit shown in simplified form in FIG. 3. It contains a phase detector 36 to which the pulses from the scanner 35 are fed. V ^{.: As will} be described below, the pulses from the scanner are first fed to an amplifier, the output signal of which is fed to a zero crossing detector. The pulses from this circuit are fed to the phase detector of the control loop. The output signal of the phase detector 36 is fed to a low-pass filter 41, which works as an integrator. The output signal of the filter 41 controls the frequency output by a voltage-controlled oscillator 40 (VCO). This frequency f2 clocks a five-stage ring counter 42, which has five output lines jzil to 5 ^ 5. The time signals appear on these f '\ lines. The frequency of the

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Signals on each line is Γ5 = l / 5f2. The signals of each of the lines, for example the line sß. with the frequency f ^ are the phase detector 56 fed.

The frequency f2 is selected to be five times as high lvert has the frequency fl, i.e. 6400. Therefore f3 = fl. If the filter 41 is absent, this has an effect any variation of the frequency fl caused by small differences in distance between neighboring bodies caused directly the frequency f2 and thus the frequency f3. Through the filter 41 is the Frequency Γ5 with a sufficiently large time constant however, it does not affect as long as the middle frequency is equal to the frequency fl over a period which is equal to the time constant of the filter.

Assuming a time constant of 7 * 8 ms, the frequency f2 remains at 6400, and the frequency fj on each of the output lines <£ 1 to j ^ 5 remains at 1280 as long as • the mean value of the pulse periods during each period of 7.0 ms equal to 0.78 nu. is. In other words: The filter, which acts as an integrator, averages the effect of the errors in body spacing and thus keeps their effect on the frequency of the time signals to a minimum. Thus, the signals on lines $ 1 to ^ 5 do not depend on the exact duration of each individual pulse period, but on the average pulse period within the period which is characterized by the time constant of the filter. Smaller deviations or errors in the distances between characters or bodies do not affect the output signals on lines οΊ to c ^ 5, as long as their mean distance is above

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several characters or bodies equal to the character division of 3.2 mm.

For example 1 and a filter with a time constant of 7.8 ras, the time signals are correctly generated with a total distance between ten bodies of 32 mm on lines 61 to ei5, although among these ten bodies the distance between two bodies opposite each other the character division of 3.2 .τλι can change. It has already been stated that very satisfactory results are achieved when the time constant of the filter is in the range of a few, for example five, pulse periods. In an exemplary embodiment with the pulse period of 0.78 »ns, a filter with a time constant of 5 ms was used.

In? Ig. 5 shows a more detailed block diagram of the invention. The sensor 35 is connected to an amplifier 44, the output signal of which is a zero crossing detector 45 is fed. This generates a pulse 46, which is in the line a in? Ig. 6 is shown. With a Belt speed of 4.1 m / sec and an exact body distance of 3.2 am has the pulse period between successive pulses 46 a fourth of 0.78 ms. However, if the distance between neighboring bodies is not exactly 3.2 mm, the pulse period deviates from this fourth onwards. In Pig. 6 there are some pulse periods with different values in line a shown. A period has a length of 0.81 ms, so that it marks a distance between two bodies, which is larger than 3.2 mm. Another pulse period has a length of 0.75 ms, so that it indicates a distance that is less than 3 * 2 mm

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is. Each pulse 46 of the zero crossing detector 45 is fed to a monostable circuit 50 via a variable delay circuit 48. The function of the comparison \ zogerungsschaltung 48 shall remain unconsidered. The function of the monostable circuit 50 is that it operates as a pulse stretcher and generates a pulse 51 for each pulse 46, the duration of which is equal to half the pulse period of 0.78 ms, as shown in line b in FIG. The output signal of the monostable circuit 50 is essentially a symmetrical square-wave signal with a frequency f1 of 1280. This output signal is fed to the phase detector 35 '"via one of its inputs.

The output signal of the phase detector 36 is the filter supplied \ 41 via an amplifier 53rd In Fig. 6, the line c shows the frequency f2 of the oscillator 40, which the;

five times vert of the frequency fl of the pulses 46 has. The i

The output frequency of the oscillator has in this case! play the V.ert 6400. The time signals on lines j

Sl to 5 ^ 5 of the counter 42 are shown in lines d to h in FIG. The signals on the five lines are labeled 61 to 65. As can be seen from FIG. 5, the output φι is connected to the phase detector 36 via a monostable circuit 67. The function of this circuit, the output of which is shown in line i in Fig. 6, is to act as a pulse stretcher for signals 61 on line φ \ . It preferably expands each signal 61 to a pulse 68 of 0.39 ms duration, so that the output signal of the monostable circuit 67 is a symmetrical square-wave signal with the ratio l / l. The output signal of the monostable circuit 67 has the frequency f3, which corresponds to the frequency fl of the pulses 5I of the monostable circuit 50.

In connection with FIG. 6 it is assumed that, given the same phase position of the pulses 57 and 68, the output signal of the ί detector 3o is constant, ie it has the fourth zero. , ι If on the other hand the two impulses are out of phase,

j as shown by dashed lines 71 and 72,

> What about incorrect spacing of the characters

^; bearing body and changes in the pulse periods compared to the value 0.78 are displayed, the output signal of the detector deviates ~ $ 6 from deffl value zero. By selecting the filter time constant with an off _; If the value is sufficiently long, however, these input voltage changes are integrated, so that the output voltage; of the filter is constant and thus the output frequency

; of the oscillator 40 remains constant at the value 6400.

; The frequency of the pulses on each output line φ \

up to <£ j remains constant at 1280, with the same periods between the pulses. Every period of 0.78 ^ms, ie during the mean transit time of each body at the sensor 35, evenly spaced time pulses are also generated on the five output lines of the counter 42, although some of the pulse periods may differ from 0.78 ms due to spacing errors .

In a practical application, the phase detector generated 36, an output with the fourth zero if the two pulses compared were 90 ° out of phase. In the same embodiment, satisfactory performance has been achieved with a filter having a Had a time constant of 5 nis.

In the embodiment described here, a further magnetic scanner 75 is used. He is

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arranged above the character body according to FIG and only evaluates a very specific body on which a metallic strip 76 is provided. This body is labeled 80. As can be seen from Fig. 5, the sampler 75 is with an amplifier 62 connected, the output signal of which is a zero crossing detector 34 is supplied. Whenever the body So passes the scanner 75, it becomes a L-npuls emitted from zero crossing detector 84. A Such a pulse 05 is shown in line j in FIG.

The ir.pulse £ 5 is a variable delay circuit 65 supplied, the output signal of which sets the counter to a certain state or counting step, for example to counting step 1. the Body So carries a certain character, for example the character I. Da is the position of the scanner 75 is known relative to the combs and the characters on the tape on each side of the body 80 are also known, the actual characters facing the hammer assembly are also known. It should be noted that the function of the scanner 35 is to detect anyone walking past it To scan bodies, v? O are generated by the pulses 46 of the zero crossing detector 45. This Pulses 46 are used to generate accurate timing signals in accordance with the invention. On the other hand, the Scanner 75 for scanning only a very specific body on the belt in order to generate a reset signal 85. If desired, other specific bodies of the tape can drive the scanner 75 so that so that other reset pulses for the control circuit 20 can also be generated.

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In practice the scanner 75 is opposite the scanner 35 moves until both have exactly a distance that is an integral multiple of the body distance of 3 »2 now is equivalent to. Thereafter, the two coupled together (dashed line 90 in Fig. 5) delay circuits 48 and So are set so that they the urinary movement time and compensate for other delays in the control of the hangers within the control circuit 20, see above ca3 the time signals supplied to each hammer group only cause characters to be printed if these are precisely aligned with the hammers.

The invention has been described above using an exemplary embodiment in which each body 30 bears only one character. However, the invention is not restricted to this. If each body 30 bears two characters, the mean distance between the bodies is 2 3.2 mm = 6.4 mm. If the character pitch is to be 3 * 2 mm and there are two characters on each body, then only a flip-flop circuit is required between the output 11 of the counter U2 (FIG. 5) and the monostable circuit 67 to halve the frequency of the pulses for the monostable circuit 67 and the detector J> 6. If each body η bears characters, then a frequency divider circuit with the factor η must be provided between the counter 42 and the monostable circuit 67.

All of the features claimed below can be used individually or be essential to the invention in combination.

Claims (3)

Protection claims 1., device for generating time signals in a data printer, in which print hammers along a print line under regular mutual distances P, are arranged and character types on a carrier along the print line movable and on the carrier at real mutual distances P are arranged, the ratio P / P. = X / Y is, X and Y are integers, and X is greater than Y, so when moving the character types along the print line of every Yth character is aligned with each X-th hammer, characterized in that the carrier is an endless belt (10) on which several elongated and spaced parallel to one another arranged support body (30) for character types are attached that each carrier body (30) on its end face facing the hammers (H) carries η character types, where η is an integer and is not less than 1, that the mean distance between adjacent carrier bodies (30) is η. P is so "" C that the mean mutual spacing of the types of characters on the tape (10) has the value P. 2. Device according to claim 1, characterized in that the hammer spacing 2.5 mm and the character type spacing 3.2 mm and that the sizes X and Y have the value 5 and 4, respectively. 3. Device according to claim 1 or 2, characterized in that η = 1 and that the mean distance between each other adjacent carrier bodies (30) is 3.2 mm.