JPS62103151A - Shuttle system serial line printer - Google Patents

Abstract

PURPOSE:To make the timing of printing accurate, by establishing the auxiliary magnetized part composed of arrangement of N and S poles by so minute pitch that their magnetic field is not practically sensitized by magneto resistance effect elements at both ends of the magnetized part of a magnetic linear scale. CONSTITUTION:A magnetic linear scale 100 is, in a united body, attached to the lower side part of a head bank and the MR element attached body 200 is fixed to a chassis. When the head bank moves linearly in the direction of A, A', the magnetic linear scale 100 moves also together therewith and each MR element linearly moves in the A, A' direction relatively to the magnetic linear scale 100. Then, the output signal Sa of a periodic waveform is obtained from output terminals 210, 212. By this system, when the MR element attached body 200 passes the auxiliary magnetized part 100a' of the magnetic linear scale 100, the waveform of output signal Sa is especially never disturbed. Therefore, the start and end of the generation of position detection pulse are executed by specific timing and the start and end of printing are carried out by an accurate timing.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a gloss type 7 real line printer that uses a magnetic linear scale and a magnetoresistive effect element as a means for creating print drive timing, particularly at the beginning of a print period. Try to get accurate and stable timing.
It's a small thing.

(Prior Art) In a shuttle type serial line printer, as shown in FIG. 8, the direction A is approximately perpendicular to the paper feeding direction B.

A' A head bank 1 is provided with a large number of printing elements (dot impact printing in Figure 8) Dl attached in an array with a fixed force direction.
A via the eccentric disk 2 by a drive motor (not shown)
, A' Each print element D during reciprocating linear movement in the force direction
i is printed at a plurality of predetermined dot positions. In the figure, 3a
and 3b are rails for guiding the head bank l in directions A and A'. The movement of the head bank 1 has a substantially sinusoidal shape as shown in FIG. 9, and is relatively fast near the beginning and end of the printing period (C1, Cbi), and is fastest at the middle point. The instantaneous position of the head bank 1 is detected at regular distance intervals by a position detection device, as shown in FIG.
A position detection pulse Pi indicating the timing when each print element is located a predetermined distance before the next dot position Qi to be printed is generated based on the position detection signal from the position detection device. The print element driving device is excited in response to the position detection pulse Pi and selectively prints each print element at the dot position Qi (that is, selectively since there are dot positions within the character that are not printed).

Conventionally, a row reno coder has been known as such a position detection device, but recently, a combination of a magnetic linear scale and a magnetoresistive element (MR element) has been used in this type of printer. .

FIG. 11 shows a position detection device consisting of a magnetic linear scale and an MR element. The magnetic linear scale 10 operates in the force directions A and A' which are substantially perpendicular to the paper feeding direction B, that is, the head bank 1.
The N and S poles are set at a constant pinoch H (
For example, 423 μm) are arranged alternately. The MR element mounting body 20 faces the magnetic linear scale 10.
'Supports the MR element Fl-F4 arranged in the force direction. These MR elements Fl-F4 are formed as a vapor deposited film or a sputtered film on a Si substrate or a glass substrate.
．． They are arranged at intervals of 5H and are bridge-connected as shown in FIG. When the MR element mounting body 20 moves in the A and A' force directions with respect to the magnetic linear scale 10, a sinusoidal sensor output signal is obtained from the output terminals 21a and 21b of the sensor circuit shown in FIG. That is, a magnetic field parallel to the film is applied to each MR element Fi, and the direction of this magnetic field is M
When the R element Fj moves one pitch H with respect to the magnetic linear scale 10, it rotates once. The resistance value of the MR element changes sinusoidally in response to a change in the direction of the magnetic field, and the periodic speed appears to double. Therefore, in the sensor circuit of FIG. 14, the MR element Fl.

The resistance value of F3 changes sinusoidally in the same phase, and these and 18
0 MR element F with different phase 2. The resistance value of F4 changes to a sine wave in the same phase, and as a result, the output terminal 21a,
A sensor output signal So of a multiplied sinusoidal wave is taken out from 21b as shown in FIG. 15(a).

For example, as shown in FIG. 16, the magnetic linear scale 10 is attached to the lower part of the head bank 1 in the body direction,
The MR element mounting body 20 faces the magnetic linear scale 10/yarn base 11 in the arrangement relationship shown in FIG.
Fixed. Therefore, henodopa/ri1 is A, A'
When linearly moving in the force direction, the magnetic linear scale 10 also moves together, and each MR element of the MR element mounting body 20 moves in the longitudinal direction, that is, A, with respect to the magnetic linear scale 10.

A relative linear movement is performed in the direction A, and as described above, a sinusoidal sensor output signal So is obtained as a position detection signal from the output terminals 21a and 21b of the sensor circuit, and this sensor output signal SO has a rectangular waveform. After being shaped and then differentiated, the amount detection pulse Pi formed from the position detection pulse Pi as shown in FIG. 15(b) faces the MR element Fl-F4 or the magnetized portion 10a of the magnetic linear scale 10. This occurs at times, and the period becomes the printing period CI, C Bi.Also, as shown in FIGS. 12 and 13, the MR element Fl-F4 is
10b, the position detection pulse Pi is not generated, and the period is the printing body stop period or the movement direction switching period c.
o, c o'. And head bank l or A, A
'When performing reciprocating linear motion in the force direction, magnetic linear scale 1
0 and the MR element Fl-F4 is the first
From the state shown in Figure 2 (printed body period CO) to the state shown in Figure 11 (
After passing through printing period CI), the state shown in Fig. 13 (printing period C
O'), then turns around and goes through the state shown in Fig. 11 (printing period C), and then reaches the state shown in Fig. 12 (printing stop period CO).
) and repeats the cycle.

(Problems to be Solved by the Invention) However, when the MR elements F1 to F4 pass both ends of the magnetized portion 10a, that is, the boundary between the printing period CI (Cl') and the printing body period CO (CO') In this case, the waveform of the sensor output signal SO was disturbed as shown in FIGS. 17(a) and (b), and this caused an error in the timing of the start and end of the printing period CI (C1"). In FIG. ,ta
is the start point of the predetermined (original) printing period C1,
Due to the undesired position detection pulse PO, printing actually starts at the wrong time t a+.

The disturbance in the waveform of the sensor output signal SO as described above is caused by an undesired waveform formed from the end of the magnetized part 10a to the non-magnetized part 10b due to the hysteresis characteristic of the magnetizing magnetic head during the manufacturing stage of the magnetic linear scale. It is generated when the MR elements Fl to F4 sense the magnetic field caused by the magnetic domain.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to provide a shuttle type serial line printer that uses an improved magnetic linear scale to obtain accurate and stable print start timing. purpose.

(Means for Solving the Problems) The configuration of the present invention that achieves the above object is to move a head bank in which a plurality of print elements are attached in an array in a predetermined direction substantially perpendicular to the paper feeding direction in a straight line reciprocating in a predetermined direction. A magnetic linear scale having a celadon part in which each printing element is driven to print at a plurality of predetermined dot positions during movement, and N poles and S poles are arranged alternately with a constant pitch in the predetermined direction, and a magnetic resistor facing the same. A shuttle-type serial line printer in which one of the effect elements moves integrally with the head bank while the other is fixedly arranged, and the timing for driving the printing element to print is obtained based on the sensor output signal of the magnetoresistive effect element. At both ends of the magnetized part of the magnetic linear scale, there are N poles and N poles at such a small pitch that the magnetic field is not substantially sensed by the magnetoresistive element.
It is characterized by providing an auxiliary magnetization section formed by arranging S poles.

(Function) When the head bank makes a reciprocating linear movement in a predetermined direction, the magnetoresistive element makes a reciprocating linear movement relative to the magnetic linear scale.

When the magnetoresistive element passes through the magnetized part of the magnetic linear scale, the N poles are arranged at a constant pitch.

A periodic waveform sensor output signal is generated in response to the periodic magnetic field of the south pole.

Further, when the magnetoresistive element passes through a portion of the magnetic linear scale that is not magnetized, that is, a non-magnetized portion, there is no magnetic field large enough to be sensed, so no sensor output signal is generated.

When the magnetoresistive element passes both ends of the magnetized part of the magnetic linear scale, it faces the auxiliary magnetized part, but here the N and S poles are arranged at an extremely small pitch, and the magnetic field is applied to the magnetic linear scale. Moreover, since the undesired magnetic domains based on the magnetic hysteresis characteristics of the magnetic node are canceled when the magnetized portion is formed, there is no magnetic field that generates the sensor output signal.

Therefore, when the magnetoresistive element passes from the non-magnetized part of the magnetic linear scale, passes through the auxiliary magnetized part, and comes to face the magnetized part, the sensor output signal instantly changes to a normal (undisturbed) waveform. This causes printing to start at a predetermined timing.

In addition, the sensor output signal, which was generated continuously with a normal waveform when the magnetoresistive element passes through the magnetized part, changes instantly when the magnetoresistive element comes to face the auxiliary magnetized part. The waveform stops without any disturbance.

(Example) The present invention will be described in detail with reference to FIGS. 1 to 7. Note that the configuration shown in FIG. 8 is also used in this embodiment.

FIG. 1 shows a magnetic linear scale 100 according to this embodiment.

The magnetized unit 100a for obtaining the position detection signal of the magnetic linear scale 100 has an N pole and an S pole of 423μ, for example.
The structure is such that they are alternately arranged at a pitch Pa of m.

An auxiliary magnetic pole 100a'' according to the present embodiment is provided at both ends of the celadon part 100a, that is, in a portion adjacent to the non-cyelamagnetic part 100b.The auxiliary magnetic pole 100a'' has an N pole and a S pole connected to a magnetoresistive element (MR). The elements are arranged alternately at a very small pitch Pa' of, for example, 2 to 3 μm so that the elements are not detected substantially. The length or extension range of these auxiliary magnetic poles 100a is approximately 1 pitch Pa (423 μm
) shows an MR element mounting body 200 according to this embodiment.

This MR element mounting body 200 has a first MR element Fl-
F4 and second MR element G1-G4 are each 0.5
A, A' are arranged in the force direction with a pitch of H, Fig. 3(a),
The first and second bridge connected as shown in (b)
sensor circuits 202 and 204 are formed.

The magnetic linear scale 100 may be integrally attached to the lower part of the head bank l (not shown), and the MR element mounting body 200 may be fixed to a chassis base (not shown). Therefore, when the head bank 1 moves linearly in the A and A' force directions, the magnetic linear scale 100 also moves together.
Each MR element of the MR element mounting body 200 performs linear motion relative to the magnetic linear scale 100 in its length direction, that is, in the A and A' force directions, and the output terminals 210 and 212 of the first sensor circuit 202 A first sensor output signal Sa having a periodic waveform (more precisely, a sine wave) as shown in FIG. 4 is obtained.

According to this embodiment, when the MR element mounting body 200 passes the auxiliary magnetized part 100a' of the magnetic linear scale 100, that is, during the period Ta in FIG. 4, the waveform of the sensor output signal Sa is particularly disturbed (pulsates). Never. This is because the auxiliary magnetic pole 100a' cancels out the disturbed magnetic domain at the end of the magnetized portion 100a, and the auxiliary magnetic pole 100a'
This is because the pitch of the magnetic field is extremely small, so that the magnetic field is not detected by the MR element.

Note that the output terminal 214.21 of the second sensor circuit 204
A second sensor output signal sb having the same waveform as the sensor output signal Sa in FIG. 4 is also obtained from 6, but the phase is 9.
Different by 0°. That is, when the head bank 1 moves in the A direction, the phase of the second sensor output signal sb is delayed by 90 degrees with respect to the first sensor output signal Sa, as shown in FIG. 5(a). However, when the head bank 1 moves in the A' force direction, the phase of the second sensor output signal sb advances by 90 degrees with respect to the first sensor output signal Sa, as shown in FIG. 5(b).

FIG. 6 shows the first and second sensor output signals Sa,
A signal processing circuit that receives Sb as input and generates a position detection pulse Pi is shown. This signal processing circuit includes first and second signal processing sections 300A and 300B having the same configuration and an OR gate 3.
It consists of 40.

The input terminal 302 in the first (language processing unit 300A)
a, 304 a is the first sensor output circuit 202
are respectively connected to output terminals 210 and 212 (FIG. 3(a)) of the sensors, and receive the first sensor output signal Sa. Input first sensor output signal Sa (Fig. 7(a))
is amplified by an operational amplifier W312a that operates as a differential amplifier circuit using resistors 306a, 308a and a feedback resistor 310a, and then amplified by an operational amplifier W312a via a resistor 314a.
It is supplied to the inverting input terminal of 8a. Operational amplifier 316a
The power supply voltage +Vcc is connected to the non-inverting input terminal of the resistor 318a.
, 320a is applied via a resistor 322a.

The level of this comparison reference voltage VRE is selected to correspond to the vicinity of the zero-crossing point of the first sensor output signal Sa supplied to the inverting input terminal. In addition, the operational amplifier 316a
A feedback resistor 324a is connected between the inverting input terminal and the output terminal, and the output terminal is connected to a pull-up resistor 326a.
It is connected to the power supply voltage +Vcc via. This results in
The operational amplifier 31ea operates as a comparator or a waveform shaping circuit, and a rectangular wave signal Ea as shown in FIG. 7(b) is obtained at its output terminal. This rectangular wave signal Ea is 328
a, and is also supplied to one input terminal of the inverter buffer 330a, CR delay circuit (332a, 334a
) and an inverter buffer 336a, it is delayed by a predetermined time Td as shown in FIG. 7(c), and the delayed rectangular wave signal Ea' is supplied to the other input terminal of the Ex-OR gate 328a. . therefore,
The output terminal of the Ex-OR gate 330a is shown in FIG. 7(d).
An exclusive OR signal Ka as shown in is obtained, and after this signal Ka passes through the OR gate 340, the position detection pulse P
The second signal processing section 300B performs the same signal processing as the first signal processing section 300A described above on the second sensor output signal sb, which is supplied to the print element driving device (not shown) as i. By applying this, a signal Kb (FIG. 7(e)) having a phase difference of 90 degrees from the signal Ka is generated, and this signal Kb is mixed with the signal Ka in an OR gate 340 and used as a position detection pulse P1 to drive the print element. Supplied to the circuit.

As mentioned above, in this embodiment, the magnetic linear scale 1
Due to the action of the auxiliary magnetic pole 100a' of 00, the printing period CI,
At the start and end of CI', the sensor output signal S a
, Sb are not disturbed, the generation of the position detection pulse P1 starts and ends at predetermined timings, and printing starts and ends at accurate timings. In addition, the first and second
Since sensor output signals Sa and Sb are generated and a double-precision position detection pulse PI is obtained from them, double-density printing can be performed.

(Effects of the Invention) As described above, in the present invention, N poles and S poles are arranged at both ends of the magnetized part of a magnetic linear scale at such a small pitch that the magnetic field is not substantially sensed by the magnetoresistive element. By providing the auxiliary magnetization section, the sensor output signal instantly appears in a regular waveform at the beginning of the printing period, so printing can be started at accurate timing.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of a magnetic linear scale 100 according to an embodiment of the present invention, and FIG. 2 is a magnetoresistive effect element Fl in the above embodiment.
-F4, a perspective view showing the arrangement configuration of G1-G4, FIG. 3 is a circuit diagram showing the connection configuration of the first and second sensor circuits 202 and 204 in the above embodiment, and FIG. In the first sensor circuit 202
A signal waveform diagram of the first sensor output signal Sa obtained from the output terminal of FIG. 5 is a signal waveform diagram showing the phase relationship between the first sensor output signal Sa and the second sensor output signal sb. The figure shows first and second sensor output signals S a, S
Fig. 7 is a timing diagram showing the signals of each part to explain the operation of the signal processing circuit, and Fig. 8 is a signal processing circuit that generates a position detection pulse Pi by inputting a FIG. 9 is a schematic perspective view showing the head bank of the printer; FIG. 9 is a diagram showing the motion characteristics of the bank; FIG. 10 is a diagram showing the predetermined dot position (Qi) and position detection pulse (Pi) in the serial line printer. Figures 11, 12, and 13 are diagrams showing the relative positional relationships between the magnetic linear scale and the magnetoresistive element (MR element). Figure 14 is the diagram showing the relative positional relationship between the magnetoresistive FIG. 15 is a waveform diagram of the sensor output signal generated by the sensor circuit; FIG. 16 is the mounting position of the magnetic linear scale and the MR element mounting body in the serial line printer. A perspective view showing the relationship and FIG. 17 are signal waveform diagrams showing problems in the conventional 7 real line printer. 1... Head bank, DI-Dn... Print element 100... Magnetic linear scale, 100a...
... Magnetized part 100a'... Auxiliary magnetized part, 100b.
...Non-magnetized part, Fl-F4, G1-G4...
Magnetoresistive element (MR element), 200... MR element mounting body, 202, 204... Sensor circuit, 300
A, 300B...Signal processing unit, 340...OR gate. Figure 1 Figure 5 Figure 7 Figure 5n (F) 'Main top soil 111 Figure 8 Figure 9 Figure 10 Figure 11 Figure 1 Brain Figure 17

Claims (1)

[Claims] While a head bank in which a plurality of print elements are mounted in an array in a predetermined direction substantially perpendicular to the paper feeding direction is linearly moved back and forth in the predetermined direction, each print element is moved to a plurality of predetermined dot positions. Printing is driven, and a magnetic linear scale having a magnetized portion in which N poles and S poles are alternately arranged at a constant pitch in the predetermined direction and one of the magnetoresistive elements facing the scale are moved integrally with the head bank. In the shuttle type serial line printer, the magnetoresistive element is fixedly arranged and the other is fixedly arranged, and the timing for driving the print element to print is obtained based on the sensor output signal of the magnetoresistive element. A shuttle-type serial line printer characterized in that an auxiliary magnetizing section is provided at both ends, with N and S poles arranged at such a small pitch that the magnetic field is not substantially detected by a magnetoresistive element.