JPH0334865A - Thermal print head - Google Patents

Abstract

PURPOSE: To reduce an electric interference due to a supply current pulse by providing a means for storing information of heating which resistor is to be heated, and a means for exciting the resistor with heat, and stepwisely switching on a resistor group at the time of starting heating. CONSTITUTION: One row of point resistors R, one set of controllers A1 to A13 and a contact member K having a plurality of contact surfaces for supplying a control signal and a current to a board are disposed on a thermal print board 1. The resistors R have 416 small resistor spots R1, R2,..., R416. A signal for deciding which print resistor to be excited is supplied to the board via one surface K. Information is shifted from the controller A1 to the controller A2 and further continuously shifted. The respective controllers contain information to decide which of the 32 resistors connected to the controller to be excited. When selected resistor is started to be heated, the resistors are stepwisely switched on until all the selected resistors are simultaneously switched on.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multi-printed circuit board and a circuit board comprising a printed circuit board and a plurality of printed resistors arranged on the board to selectively perform electrical heating. - Regarding the multi-print head.

1. Prior Art] →Normal printheads of the type described above are well known. In such a head, the substrate is usually formed as a rectangular plate, on which a large number of small printed resistors, up to several pieces, are arranged adjacent to each other along a straight line. A thermally sensitive web is fed into the head in a staggered fashion so that it is in contact with the resistor.For each "tj" of the web, a short pulse of current is delivered to a selected resistor. In particular, the desired printer l-resistors of the Eri1 phase are energized (11), then they are heated to produce a drag (11i) on the paper.The web is then moved one step; A new set of printed resistors is energized and so on. Thus (note,
Characters, figures, graphic information, etc. can be recorded on the web.

If all or a majority of the printed resistors are energized at the same time, the total supplied current pulse to the thermal print head can have a high amplitude, reaching up to several tens of eights. The flanks of the current pulse are therefore very steep both during switch-on and during switch-on. These steep sides cause significant electrical interference and produce electromagnetic emissions.

When switching on or off a printed resistor,
It has been found that transients can be reduced by a suitably constructed thermal inductor. However, they must be sized for the full supply TXIE and the load mains of maximum amplitude, so elements of this type become significantly more complex and the price J=V? -1, It is difficult to attenuate the wandering phenomenon in long hits using this method.

One-normal printed heads of the type referred to here are known to provide non-overlapping group feeding or non-IL group excitation of printed resistors with a view to reducing the amplitude of the total supply current. However, this requires the addition of multiple contact surfaces for the thermal print head, which not only reduces the reliability of the system of which the head is a part, but also increases complexity and storage. Accompany.

Furthermore, this current supply 11; t1! J! ``'Q reduces printout speed and writing quality.

The present invention provides and seeks to provide a glue-print head of the type described in the preamble of the specification, whereby the side steepness of the supplied current pulses is significantly reduced and therefore the electrical interference caused by the supplied current pulses is significantly reduced. reduced. Furthermore, the present invention attempts to reduce the electrical interference described above without limiting the amplitude of the supplied current in any way. The present invention further seeks to provide a thermal printhead that requires a minimal number of contact surfaces and only a fractional H1 control signal to supply current to the resistor.

1 Embodiment FIG. 1 shows an example of a printed circuit board 1 according to the present invention. On the board, which is a rectangular plate of insulating material, there is a row of printed resistors R, a set of control circuits 1 to A13, and a plurality of contact surfaces for supplying control signals and current to the board] A contact member K is arranged. Above this, the necessary electrical connections between the units on the veneer are also arranged. However, for reasons of simplicity, these connections are not shown.

Pudding 1 to resistor R consist of 416 small resistor spots R1, R2...R416. These are arranged adjacent to each other along a straight line, as shown in Figure 1b. Printed resistors can be suitably designed with thick-film or N-film technology, for example with a negative side of 0.
It can be a rectangle as shown in 1b of 2bs.

1 lint resistor *t+-a, 13 control circuits A1. A2...A13 are arranged on the substrate. These consist of silicon chips, which are integrated circuits manufactured by conventional methods and mounted on a substrate 1-L.

The control circuits are identical to each other and each control circuit is connected to 32 printed resistors to control each one.

FIG. 1C shows a thermal print head according to the present invention. The head has a substrate 1 formed by the method shown in FIGS. 1a and 1b. Two control circuits on the board, A.
Only , and , are shown.

11→1 Single plate tfl is arranged between two light metal parts 11 and 13. The part 11 constitutes a cooling body for the substrate, for example a high thermal conductivity silicon layer 12 is arranged between the cooling body 11 and the veneer. The portion 13 constitutes a protective hook and has a projection 131 that fits into the groove 111 of the cooling body. The parts 11 and 13 are held in place, for example by screws 17a, 17b, and threaded holes (for example in the collars 4132a, 132b) are provided in the parts 11.13, the substrate 1 and the layer 12. .13 and the substrate, a hose or strip 14.15 of elastic material, for example silicone plastic, is provided in the portion 11.1.
It is arranged between the three substrates and the first substrate. A flat contact strip 16 is arranged in communication with the contact of the substrate, and at its opposite end a contact member 161 is provided.

Figure 1d differs from Figure 1C in that the thermal print head has two substrates, namely a thermal printed circuit board 1a and a second substrate 1b. Board 1
a supports the printed resistor R and all or some of the control circuits A, , A, +1. In the simplest form, the board 1b has wires (not shown for simplicity) that connect the board 1a to the contact member 1 and the print head.
” will be established. 1 is profile 1 for contact member
It fits into the recess 112 in 1.

Also, some or all of the control circuits of the print head can be disposed on the substrate 1bl, as shown by the square breaks 11BI and B2.

Not shown in FIG. 1d are the connection means necessary for transmitting signals and supplying currents and voltages between the two substrates.

The width of the print head is, for example, 45 m in the paper feed direction σ1 (horizontal direction shown in Figures 1C and 1d), and the direction perpendicular to this (horizontal direction tJ in Figures 1C and 1D) is 45 m.
), it can be set to 100 m, for example. Portion 13 may have a width of 35 m in the feed direction, so that the inside surfaces of substrates 1 and 1a are exposed to a width of approximately 10#lII+ along the edges where printed resistors R are arranged. . The printed paper continues to be in contact with this free surface and thus with the printed resistor R by means of a roll or the like.

FIG. 2 shows three (9) paths of the 13 control circuits, namely Al, A2. A13 is shown. l! 1 to the circuit is resistor R1
~R32 to control it, circuit A2 is connected to resistors R33-R64, circuit A13 is connected to resistor R38
5 to R416. One end of each printed resistor is connected via one contact surface K to a supply voltage U applied to the substrate. The supply voltage flowing to the substrate is denoted by I. The other end of each resistor is connected to one control circuit.

This end of the resistor is normally held by the control circuit at a potential equal to the supply voltage (J, and no current flows through the resistor. When the resistor is energized, the end of the resistor connected to the control circuit A current pulse is passed through the resistor which is placed at a potential of eg OV for a certain time and which heats the resistor.

The signal @ I) AT A which determines which printed resistor is to be energized at a given time is supplied to the substrate via one contact direction K. This information consists of digital signals in series format containing 416 bits, one for each printed resistor. As mentioned later, Will I
The IiJ paths include units that together form a 416-bit shift register. When writing the recorded word to the printhead, the information is passed from 1 to control 1! to the control circuit until all 416 bits have been shifted to the KAJm circuit. ” path, 2, and the next, and so on. Each control 11U path contains information that determines which of the 32 resistors connected to the control circuit should be energized. The information shifted from control circuit 0 A1 to circuit A2 is indicated by symbol D in Fig. 2.
33, information transferred from A2 to shift 1 is indicated by reference numeral 1)85'c, and in the same manner, information transferred to the last control circuit A13 is indicated by D385. The reading of said information is controlled by a clock pulse C1- supplied to the print head.

The read information is stored in each control circuit in the holding circuit and starts on a pulse LO which is supplied to the printhead. Thereafter, a pulse LO of a duration equal to the desired heating time of the resistor -4 The selected resistor 1 is excited by the control pulse STR.

Information and control signals of the print head can be transmitted in a known manner by suitable digital recording, such as a microphone processor.

FIG. 3 shows an exemplary embodiment of the 13 control circuits 1]1, 1, and 1 for the ri+ of the circuit. This 4 consists of 32 identical units, one for each resistor 1 to R32 connected to the control circuit.
FIG. 31 shows a method of shifting between 32 -1 nits in the 11 circuits controlling miDA1A. Information D2 from unit B1 to unit 132
is shifted, and information D is transferred from unit B2 to unit B1.
3 is shifted, and then shifted to F Irjl. 32 [! The +1 nit contains a member that stores the first 32 bits of the information word that determines which printed resistor is to be energized. If the entire data order has been loaded into the thermal print head, a binary digit indicating whether the associated printed resistor should be heated is sent to unit 81~
1332 each contains.

Pulses OL and LO are all fed to the unit of FIG. Control pulses si+<c are supplied only to the first unit 131. As will be described later, the control pulse s −r [< i, in the unit 131 is delayed by a predetermined time, and the thus delayed pulse is supplied to the unit B2.

At this point, the received pulse is
The coarsely delayed pulse S T R3, which is delayed by an equal amount of time between k'i, is fed to unit B3, and so on.
Finally, 2 fl delayed control pulses are received.

51 nits [31 to B32 in Figure 4 and Figure 3]. The unit (~ is connected to the resistor R to control it. When reading the data 1ifi@, the control information 1) is 1 bit.
1, supplied to the knob [1, fi J, the output signal of the flip-nor knob is set equal to the human input signal and the next 1-nit correspondence in the form of a signal Di, +1. The bistable Noripno[ltub[i,
1. , after 416 glue r-, 1 tick pulses, the entire f-taper has been shifted into a shift register formed by 416 bistable knobs included in the print head. . The output of flip knob 2 (gM is also fed to another edge-triggered bistable flip knob.) Once the entire word is read into the shift 1 register (gM), the printhead will pulse LO , which is supplied to the flip knob and sets it according to the human input +4 of the flip knob.1Flip knob 1] The output signal of knob 1- is the control pulse supplied to the unit in question. SIR・
It is also supplied to the AND circuit. Usually, the control pulse is logic 1]'C'', which means that the output signal of the circuit is usually logic 1'C-, ANI)
The output signal of the circuit is "high" and no current flows through resistor R1. During the desired heating time of the selected printed resistor, the control pulse STR is a logic one. For each selected resistor,
The signal DAl-A contains a logic 1 which is stored in the flip block after being read. When the control pulse STR changes from logic O to logic 1, the output signal of the AND circuit of the selected resistor changes from logic 1 to logic 0, and the selected resistor changes for the duration of the control pulse S'I-R. A current passes through the device. For non-selected resistors, the information D A T A contains a logic 0, the output signal j from the resistor knob 1 = , of such a resistor is a logic O, and the output signal to the AND circuit circuit is a logic 1 Therefore, the IX current does not pass through the resistor.

As shown in FIG. 4, one circuit also includes a delay circuit 1-1 that delays both the switch-on and switch-off of the control pulse S"I-R received by the delay circuit. (, output signal 5IR11 of the delay circuit
consists of a control pulse of the same duration as the incoming control pulse S T l-<. and delayed therefrom by a time tf.

Figure 5 shows the pulse C arriving at the legal print head.
1,, -, L O and S -1' R1 Control pulse S T R2 that determines the heating section of resistor R2, control pulse S I-R32 of resistor 32, and the total current 1 from the current source over time as a function of; JX−'J.

l) A ”I- to the print head in the interval t1
The reading of E is started and after 416 pulses CL the reading is completed and the binary number determining the selected printed resistor is stored in the flip-flop 13.

The final pulse of the 416 glue 1' pulses occurs at time [2]. Thereafter, the printer head receives the pulse LO at time 1'3, and the information stored in the flip-flop 1] is transferred to the flip-flop I"] knob [-1, after which the desired upstream , Fringe “)”1 Tsuzo l-
You can start reading new l) A I-A. Once the flip-flop is set, one normal printhead receives a pulse STR that determines the heating time of the selected resistor.

This control signal starts at time t4 and ends at time tf. Therefore, the first resistor (R1, R3
3, R65, etc.) is started at time t4 and from time 1-7.
It ends with. At time t5, unit B1 (see FIG. 3) sends a control signal S-1-112 to unit B2. As a result, once each resistor □ is selected, the second resistor (R2 , R34, R66, etc.) are switched on. The process continues with the subsequent switching on of more printed resistors as well.

At time t6 43, a control signal S I R 32 is sent to the last unit in each group. In this regard, the following formula applies: .

t 5-t 4-+-4f eyes t6-141-31Xtf 6 bu lint head It increases stepwise at t=t6, and reaches the maximum value at t=t6.

Similarly, the supply current is -3 between t-=-t7 and t-t9.
Reduce by 2 speeds.

In the printer 1 to head, the delay time tf is, for example, 0.211S. Control pulse S'-
The duration of 1"l'< , is at least 06.4 μS (3
2×0.2 μs). In the application shown in FIG. 1, bI'j=I, constant current supply period 1, 6.about.t7 can be obtained. With this technique, it is possible to adjust the delay time tf so as to obtain an appropriate side surface finish and minimize electrical interference and electromagnetic interference.

The delay 11!1 path 11 can be set appropriately as shown in FIG. Each delay path has two inverters,
! It is composed of N1 and IN2.

Delayed control (F month S'T-R is inverter I
N1 and delay controlled 'i: S -1' R
, , 14 are obtained as output signals from impark IN2. The delay time is the combined delay time of the two inverters. This delay time can be adjusted depending on the relationship between the Ti flow drive amount 'f#' between the two inverters.

With the printhead according to the invention, the lateral steepness of the supply current is controlled and reduced both in the switch-off phase and in the switch-off phase. In this way, the thermal printhead can significantly reduce electrical interference due to supply current pulses in a simple and advantageous manner. Moreover, as can be seen from the above description, the thermal printhead according to the invention requires a minimum number of contacts 1 to supply control signals and current, reducing the cost of the contact members. reliability is improved4.

The embodiment described above is but one of various ways of designing a legal printhead according to the present invention. The control circuitry included in the printhead can be formed in many other ways while still maintaining this functionality in accordance with the present invention.

Of course, the number of control circuits may be different from the number 13 mentioned above, and this also applies to the number 416 of printed resistors.

In addition, the printhead according to the invention can also include an additional m1 circuit without affecting the interference between the printhead and the control digital H&.However, these M'13111till ti11
The circuit does not change the switch-on and stepwise control of the printed resistor according to the present invention. Further, in the above example, the C1 printhead has one row of printed resistors arranged in a cross 71 pattern, but the present invention has multiple parallel rows of printed resistors. Of course, the print head which generates the risk at 161 hours can also be passed through.

[Brief explanation of the drawings] The 18th test is the 18th test using a multi-print veneer according to the present invention.
< Detailed phase diagram of the printed resistor on the thermal printed circuit board according to Fig. 1, Fig. 1b (or Fig. 1a)
FIG. 1C shows another thermal print head according to the present invention, FIG. 1C shows FIG. 10 and the first separate veneer, FIG. Figure 3 shows one of the 13 control circuits of the normal print head, and Figure 4 shows the detailed control circuit for the 111!!l printed resistor. 1 and 5 are diagrams showing the supply current of the print head and certain signals occurring in the thermal print head as a function of time (not shown).
Figure 6 is shown in Figure 4'? FIG. 1 shows a design example of a 1' delay I11 path. Explanation of reference symbols 1.1a, 1b...Thermal printed circuit board 11.13
...Light metal part 12...9917 layer 14.15...Bose b (Yo strip 16...
・]Ntactos 1~Lip 17a, 12b---Screw 131---Protrusion A1~A 13---To control circuit B1-1332---Conit E1~[416,E・,``,---Noritsub Flop G,...AND circuit i...Delay circuit 0 INl, IN2...Inverter, 1.161...] Turn 1~Delay circuit, R1-
R416...Resistor

Claims (4)

[Claims] (1) A thermal print head comprising a thermal printed board (1) having a plurality of printed resistors (R1 to R416) arranged on the board so as to selectively perform electrical heating, the thermal print head storage means (E_i, F_i) for receiving and storing information (DATA) for determining which printed resistor is to be heated at a given time, and a selection resistor according to an excitation signal (STR) supplied to the print head. An excitation means (G_i) is provided to heat and excite the thermal printhead, and the thermal print head switches on the printed resistors in stages at the start of heating and switches off the printed resistors in stages at the end of heating. A thermal print head, characterized in that it comprises a member (H_i) made of (2) In the thermal print head according to claim (1), the first group of printed resistors (R1, R33, R6
An excitation signal (STR) is supplied to the excitation members (B1, B33, B65, etc.) of the printheads (B1, B33, B65, etc.), and the printhead then prints another group of excitation members (B1, B33, B65, etc.) with successively increasing delays. A delay member (H_
A thermal print head comprising i). (3) In the thermal print head according to claim (2), the delay member includes a delay circuit (H_i),
A group of printed resistor excitation signals (STR_
i) are supplied and their output signals (STR_i_+_1
) is sent out as an excitation signal for another group of printed resistors. (4) In the thermal print head according to any of the above claims, the member (H_i) that performs stepwise switching on and off of the printed resistors is configured such that when heating of the selected resistors starts, all the selected resistors A thermal print head characterized in that the resistors are switched on in stages until the resistors are switched on simultaneously.