JP3297101B2 - Serial printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer, and more particularly to a serial printer having a synchronizing signal generating circuit for synchronizing the movement of a carriage having a print head and the printing operation of a print head.

[0002]

2. Description of the Related Art In a serial printer, printing (printing) is performed while scanning a carriage on which a printing head of a printing means is mounted in a horizontal direction with respect to a printing medium. Then, density unevenness of the recording result occurs. In particular, in a color printer, a shift in color registration occurs, which is a problem.

Conventionally, as one method for solving these problems, a configuration in which the amount of movement of a carriage equipped with recording means with respect to the apparatus main body is detected, and the recording operation is performed by the recording means while synchronizing with the detection result. It has been known.

That is, a scale section of a linear encoder is fixed on a main body side, and a detection section of a linear encoder is mounted on a carriage which moves relatively to the scale section, and an output signal from the detection section is amplified. Then, the recording signal is taken out of the carriage and a recording signal is generated in synchronization with the amplified signal, thereby preventing print density unevenness and color registration deviation.

FIG. 6 is a perspective view of a main part of a serial printer shown together with a recording medium. In FIG. 6, a carriage 1 indicated by a dashed line carries a recording unit 2 such as an ink jet recording system, and is guided by a guide shaft 3 having a spiral groove formed on an outer peripheral surface, and is locked by the rotation of the guide shaft 3. A portion (not shown) is driven along the spiral groove, and is reciprocally driven in a direction indicated by an arrow in the drawing with respect to the recording sheet 5 wound on the outer peripheral surface of the platen 4, and a recording sheet (recording medium) A so-called serial printer that forms dots and images by printing dots D at a pitch P on the print head 5 is formed.

[0006] The carriage 1 constructed as described above is provided with an encoder for obtaining a synchronization signal. This encoder is a magnetic linear encoder, which records a magnetic pattern on a magnetic material formed on the surface of a wire at a print pitch density corresponding to, for example, 180 dots / inch (dpi) or 360 dpi, or a scale portion of a linear encoder. 6 is fixed to the apparatus main body 7, while a magnetic head main body 101 composed of an MR element or the like is fixed inside the carriage 1, and enables position detection by movement of the carriage 1.

Further, a flexible printed circuit board 8 for extracting an output signal from the MR element in the magnetic head to the outside is connected to the detecting section 101, and a contact section 9 is connected to a connector (not shown). Thus, the carriage substrate 104 (shown by a broken line) mounted on the carriage 1
To connect to.

The carriage substrate 104 and the recording section 2
Is a flexible cable 10 attached to a printer control circuit board 109 fixed on the main body 7 (shown schematically).
Are electrically connected via

FIG. 7 is a block diagram showing an example of a circuit configuration of the serial printer shown in FIG. In FIG.
The detection unit 101 of the magnetic linear encoder, which detects the magnetized information on the scale unit of the magnetic linear encoder mounted on the carriage and fixed to the main body side and detects the relative movement position of the carriage, has a magnetic resistance. Magnetic sensing elements 102, 10 each composed of an MR element operating based on the effect
3 built-in. Further, the detection unit 101 is connected to a carriage substrate 104 (shown by a broken line in FIG. 6) mounted on the carriage. This carriage substrate 104
It has constant current circuits 105 and 106, and a differential amplifier 107 that differentially amplifies each signal detected by each detection element, and outputs an output signal A ₀ (or 10
8) is output.

[0010] The printer control circuit board 109, generates an output signal A ₀ and A / D converter 112 for converting A / D, the counter pulse A pulse waveform by comparing the reference voltage and the output signal A ₀ (or 111) Comparator 110
A D / A converter 114 for generating a reference voltage V _ref (or 120) as an input signal of one terminal of the comparator 110, a counter / timer 113 for counting a counter pulse A, and a CPU 11 for controlling the system
5 and storage devices such as EEPROM 116 and ROM 11
7, a RAM 118, and a CPU bus 119 which is a bus for data, addresses, and control signals of the CPU 115. Note that some or all of the components shown in the broken lines may be incorporated in the CPU 115.

Next, the operation of the above circuit configuration will be described. Each of the magnetic detection elements 102 and 103 has a constant current circuit 105,
A constant current is supplied through the sensor 106, and the detection unit 101 is moved along the scale unit 6 (see FIG. 6) of the magnetic linear encoder fixed to the main body side in which the magnetic pattern is magnetized at predetermined intervals. When moved, the magnetic sensing element 102,
The resistance value of the resistor 103 changes, and the amount of change in the resistance value is detected as a voltage change, amplified by the differential amplifier 107, and then the amplified signal is input to one input terminal of the comparator 110.

The output signal A ₀ from the differential amplifier 107 is a pseudo sine wave.
Reference voltage V _ref output from D / A converter 114
And a counter pulse A is obtained as a synchronization signal. The counter pulse A is input to the counter / timer 113 and counted, and the count value indicates the position of the carriage. The CPU 115 controls the system.
It transfers data to and from the ROM 116, the ROM 117, and the RAM 118, controls the A / D converter 112, the counter / timer 113, and the D / A converter 114. Other functions as a serial printer (for example, interface with a host) Function, control of various motors, printing operation, etc.).

As described above, since the output signal A ₀ obtained from the detector of the magnetic linear encoder is a pseudo sine wave, the converter 110 converts the output signal A ₀ into a counter pulse A represented by a digital signal (pulse waveform). Need to convert. On the other hand, it is desirable reference voltage V _ref to be compared is input to the comparator to be used in the conversion and the output signal A ₀ is an average value of the output signal A _0, Therefore,
As the reference voltage V _ref is an average value of the output signal A ₀ is necessary to initially adjust.

The procedure of the initial adjustment of the reference voltage V _ref in the conventional example will be described below with reference to the flowchart shown in FIG. 8 (V _ref initial adjustment 1). FIG. 8A shows a main routine for initial adjustment of the reference voltage _{Vref in} the conventional example. FIG. 8 (a)
, The movement of the carriage is started (step S
1). At this time, since the counter pulse from the linear encoder has not yet been correctly output, the moving speed is not known. For this reason, the minimum torque that can move the load based on the mechanical components such as the carriage and the guide shaft is obtained in advance, and the CPU instructs the carriage to move at a speed that is not too fast. Next, the differential amplifier 10
By detecting the output signal A ₀ from 7, A digital value D / A converter 11 the average value as a reference voltage V _ref of ₀
4 (step S2). Next, the carriage is returned to the initial position (Step S3).

[0015] Next, with reference to FIG. 8 (b) will be explained in detail the contents of the aforementioned step S2, first, as initial setting, A ₀ predetermined number n (1 or more integer number of measurements ) Is set in the counter, and at the same time, the addition area A _sum of A ₀ is cleared (step S11). Next, A / D
After A / D conversion of the data of A ₀ using the converter 112, the data is taken into the RAM 118 (step S12). Next, the counter is decremented and A ₀ is added to A _SUM.
Is added (step S13). Next, it is determined whether or not the counter is 0 (step S14). If it is not 0, the process returns to step S12, and if it is 0, the process proceeds to step S15. That is, until the counter becomes 0, Step S12,
Repeat step 13. When the counter reaches 0 in step S14, the carriage is stopped (step S15). Next, the average value A _ave of A ₀ is obtained by dividing A _SUM by the number of measurements n (step S16). Next, a digital value such that V _ref = A _ave is set in the D / A converter 114 (step S17). Finally, the EEPROM 116
To store the digital value set in step S17.

[0016] As described above, since the moving speed of the carriage is not known at the time of the reference voltage V _ref initial adjustment, the A ₀ A / D
The period T of the pseudo sine wave whose conversion sampling period is A ₀
Mean value if _A0 integral multiples become such a A _ave an ideal reference voltage V _ref, i.e. there is an error of the DC component of A ₀ is increased. FIG. 9 shows such a case. If the average value A _ave having a large error is set in the D / A converter as the reference voltage V _ref , a counter pulse having a duty ratio greatly deviated from 50% will be output.

The reference voltage V _ref is an ideal reference voltage V _ref
FIG. 10 shows a case where the relative deviation ΔV occurs between the average value A ₀ and the reference voltage V _ref in the case of the case of FIG. The relative displacement occurs due to a temperature change, a temporal change in a gap between the scale unit and the detection unit of the linear encoder, and the like. Paying attention to the falling edge of the converter output, it can be seen that Δt ′ in the case of the reference voltage _{Vref having} a large error is larger than the edge fluctuation Δt in the case of the ideal _Vref .

In this conventional example, dots are printed in synchronism with the edge of the output of the comparator. If the fluctuation of the edge is large, the pitch will not be equal, and the density of the recording result will be uneven. In particular, in a color printer, there is a problem that a color registration shift occurs.

For this reason, the above-mentioned conventional reference voltage V _ref
A serial printer using the reference voltage initial adjustment method that has improved the disadvantages of the initial adjustment method has been applied for a patent application of the earlier application (reference number 2).
404148) (Japanese Patent Application No. Hei. No. hei 10-294).

Next, the proposed serial printer will be described. Note that the hardware of the serial printer has the same configuration as that of the conventional example already described with reference to FIGS. 6 and 7, and a description of the hardware will be omitted. FIG. 11 is a flowchart showing a sequence of initial adjustment of the reference voltage Vref of the comparator ( _Vref
Initial adjustment 2).

In FIG. 11, steps S21 to S23
Are the same as steps S1 to S3 of the conventional example shown in FIG. These steps S21 to S23, normal values can be obtained to some extent as a counter pulse A _0.

Next, the carriage is moved again (step S24). Next, steps S25 to S27 are performed, and these steps are a carriage speed control loop. That is, the speed of the carriage is detected (step S2).
5) It is determined whether or not the carriage speeds are synchronized (step S26). If not, the carriage speed is adjusted (step S27), the process returns to step S25, and the carriage speed is detected again, and again. It is determined whether or not the carriage speeds are synchronized, and steps S25 to S27 are repeated until the carriage speeds are synchronized. When the carriage speeds are synchronized, the process proceeds to the next step, step S28.

Here, in step S27, the carriage speed is adjusted by reading the count value of the counter pulse A of the counter / timer so that the period of the output A ₀ of the MR element is changed with respect to the sampling period T _S of the A / D converter. This is performed by adjusting the speed of the carriage so that the following relational expression 1 holds. T _S = T _A0 / 2 ^m (m is an integer of 1 or more) (1) FIG. 12 shows an example in which the relational expression 1 holds.

[0024] If this time, T _S is variable, without changing the T _A0, i.e. without changing the moving speed of the carriage may be changed so that only the T _s equation 1 is satisfied.

Next, in step S28, by measuring n times A ₀ at intervals of T _s and calculates an average value A _ave. This step S28 is the same as steps S11 to S18 of the conventional example already described with reference to FIG. However, the number of measurements n must satisfy the following relational expression 2. n = k · 2 ^m (2) (where m is the same as m in the relational expression 1, and k is an integer of 1 or more). FIG. 12 shows an example in which the relational expression 2 holds.
Is shown in In the example of FIG. 12, m = 2 and k =
2, n = 8.

In order to make the average value A _ave of the n times of measurement equal to the DC component of A ₀ , it is sufficient to perform the sampling at the point where the phase of A ₀ is 180 ° out of phase. In the example of FIG. , Points 201 and 203, points 202 and 204, point 2
It can be seen that the values at 05 and point 207 and the values at points 206 and 208 cancel the error with the DC level of A ₀ , respectively.

Finally, the carriage is returned (step S29), and the initial adjustment of _Vref is completed.

[0028] Incidentally, aforementioned reference voltage V _ref initial adjustment sequence, usually a serial printer is performed only once before being shipped from the factory, when time course of A ₀ output is large, for example, use Sometimes, a sequence of initial adjustment of the reference voltage _Vref may be incorporated in the initialization sequence after the power is turned on. As mentioned earlier, the EEPROM
Is set in the D / A converter in an initialization sequence after the power of the serial printer is turned on.

[0029]

However, the above-mentioned prior art or the prior art method for adjusting the reference voltage of a serial printer has the following disadvantages. This disadvantage will be described with reference to FIG. 13. Even if the average value of A ₀ can be accurately measured by the reference voltage initial adjustment method of the conventional example or the prior application, the DC component of A ₀ depends on the position of the carriage. When it changes, the output of the comparator becomes
Duty ratio as (b) not only deviates significantly from 50%, the carriage position where the variation of the DC component of A ₀ is shifted larger than the average value of A ₀ is possible to generate a counter pulse A I can no longer do it.

For this reason, the positions and intervals of the dots to be printed are disturbed, and the quality of the recorded result is significantly impaired. A
_The change due to the carriage position of the DC component of ₀ is mainly caused by a change in the gap between the scale section of the magnetic linear encoder and the MR element of the detection section. It is difficult to suppress the change in the gap in the entire moving range of the carriage, and it is mechanically expensive.

Therefore, an object of the present invention is to provide a reference voltage for obtaining an ideal reference voltage over the entire moving range of the carriage even when the gap between the scale section of the magnetic linear encoder and the MR element of the detection section is not constant. An object of the present invention is to provide a serial printer capable of initial adjustment.

[0032]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a recording apparatus which performs reciprocating motion on an apparatus main body and performs recording by a recording means while synchronizing the movement of a carriage on which the recording means is mounted. In the serial printer device to be performed, a scale section of a linear encoder provided on the apparatus main body, a detection section of a linear encoder mounted on the carriage to detect the position of the scale section,
Synchronizing signal generating circuit means for receiving a signal output from the detection unit as an input signal and comparing the signal with a reference voltage to generate an output signal having a pulse waveform as a synchronizing signal; and the reference voltage input to the synchronizing signal generating circuit means Reference voltage initial adjustment means for initial adjustment of the carriage, wherein the reference voltage initial adjustment means is divided by the movement range blocking means for dividing the movement range of the carriage into blocks, and divided by the movement range blocking means. And a reference voltage calculating means for calculating a reference voltage for each block.

[0033]

Next, preferred embodiments of the present invention will be described.
FIG. 1 is a flowchart showing the operation of the reference voltage V _ref initial adjustment method of the first embodiment of the serial printer of the present invention (V _ref initial adjustment 3). The hardware of the serial printer is the same as that of the conventional example shown in FIGS.

In FIG. 1, first, the aforementioned _Vref initial adjustment 2 steps (steps S21 to S2 shown in FIG. 11)
9) is performed (step S31). Next, 1 is set as the block number, that is, the block number is initialized (step S32), and the movement of the carriage is started (step S3).
3) Initialize the A ₀ addition counter and the addition area A _SUM (step S34). Then, the A / D converter to measure the A ₀ voltage (step S35), the up counter incrementing (adding 1) and A to A _SUM
0 is added (step S36), and the position of the carriage is detected from the counter / timer (step S37).

Next, it is determined whether the position of the carriage has reached the next block (step S38). In addition,
Here, the block means one unit in which the moving range of the carriage is divided at predetermined intervals in advance, and the above-mentioned block number means a continuous number assigned to each block incremented according to the movement of the carriage. . Step S
If it is determined in step S38 that the next block has not been reached, steps S35 to S37 are performed until the next block is reached.
repeat.

If it is determined in step 38 that the carriage position has reached the next block, the average value A _ave is calculated by dividing A _SUM by an addition counter (step S 38).
39). Next, the average value A _{ave at} the position of the carriage indicated by the current block number thus obtained,
That is, a digital value to be set in the D / A converter as the reference voltage _Vref is stored in the area of the EEPROM corresponding to the current block number (step S40). Next, the block number is incremented, that is, updated (step S41), and the updated block number is set to a predetermined final block number (= division number of carriage position).
It is determined whether or not it is larger than (Step S42).

If it is determined in step S42 that the current block number is not larger than the last block number, the process proceeds to step S42 until the current block number becomes larger than the last block number.
Repeat from 34 to S42. Thus, the average value A _{ave for} each block is stored in the corresponding area of the EEPROM. If it is determined in step S42 that the current block number is larger than the last block number, the carriage is stopped (step S43),
The carriage is returned to the initial position (Step S44).

Next, the operation of the flowchart shown in FIG. 1 will be described with reference to the timing chart of FIG. FIG. 2 shows the differential amplifier 1 with respect to the position of the carriage.
07 (see FIG. 7), the ideal reference voltage V _ref which is a DC component of the output signals A ₀ , A ₀ , the ideal counter pulse A (a) in that case, the average of A ₀ over the entire carriage movement range. Counter pulse A when the value is V _ref
5B is a timing chart showing the relationship of the counter pulse A (c) when the average value in the block of A ₀ is _Vref . This embodiment shows a case where the moving range of the carriage is divided into four blocks.

At step S31 in FIG. 1, the counter pulse A can be obtained to a sufficient degree for dividing the carriage position into blocks although the waveform is not an ideal waveform as shown at A (b) in FIG. One block may be sufficiently longer than the period of the counter pulse A (for example, 360 dpi), and the accuracy of the position of the boundary of the block may be significantly lower than the accuracy of detecting the carriage position required for printing. The counter pulse A at the end of step S31 may not be very accurate.

In step S32, the block number is initialized, and in step S33, the movement of the carriage is started. In step S34, the A ₀ addition counter and the addition area A _SUM are initialized, and in steps S 35 to S 38, A ₀ is periodically sampled and added to A _SUM until the carriage position exceeds the range of the current block number. In step S39, the average value A _ave of A ₀ at the current block number is obtained. In step S40, the digital value for setting in the D / A converter for setting V _ref = A _ave is stored in the current block of the EEPROM. Store in the area corresponding to the number. In step S41, the block number is incremented. In step S42, the current block number is compared with a predetermined final block number (4 in the embodiment of FIG. 2), and the current block number does not exceed the final block number. out by repeating the steps S34～42, continue to store each digital value of the candy to set the average value of a ₀ to the D / a converter as V _ref in each block in the EEPROM. When the digital values of _Vref in all the blocks have been stored in the EEPROM, the carriage is stopped in step S43, and step S43 is performed.
At 44, the carriage is returned.

[0041] in FIG. 2 A (c), the counter pulse A when the average value of A ₀ in each block is changed to step form a V _ref in accordance with the position of the carriage so that the V _ref
And V _ref is A _{0 in the} entire carriage movement range.
Is closer to the ideal waveform of A (a) than the waveform of A (b) when the average value is obtained.

As for the number of blocks, EEPRO
It may be set optimum value by the amount of variation of the DC component of the margin and A ₀ of the area of M. For example, large amount of variation in the DC component of A _0, the number of blocks when the area of the EEPROM is long free enough many people (i.e., block the finer one) is better. In general, it is preferable to divide the blocks at regular intervals, but irregular intervals may be used as long as there is room for the load of software and the area of the EEPROM. In this case, it is necessary to store even EEPROM carriage position of the boundary of the block is effective in a case where there is a locally large change in the DC component of A _0.

Next, an operation at the time of printing in the first embodiment of the present invention will be described with reference to FIG. As described above, since the moving range of the carriage is divided into blocks and the reference voltage _Vref is set for each block, a printing operation corresponding to this is required. FIG. 3 shows a flowchart for printing one line in such a case. In this flowchart, steps S51 to S52 and steps S58 to S60 are added as the first embodiment of the present invention, and the other steps are the same as those of the conventional example.

In FIG. 3, in step S51, 1 is inserted as the block number, that is, the block number is initialized.
In step S52, the reference voltage _Vref corresponding to the block number 1 is set in the D / A converter. Step S53
Then, the movement of the carriage is started, and steps S54 to S5 are performed.
In a loop of 6, the carriage speed is set to a predetermined speed.
That is, in step S54, the speed of the carriage is detected,
In step S55, it is determined whether or not the speed is a predetermined speed. If the speed is not the predetermined speed, the speed of the carriage is controlled in step S56, and thereafter, the process returns to step S54, and steps S54 to S56 are performed until the speed becomes the predetermined speed. repeat. Next, in step S57, printing is performed at a predetermined position.

Next, in step S58, the position of the carriage is detected, and in steps S59 to S61, it is determined which block the carriage is currently in. When the boundary of the block is exceeded, the reference voltage _Vref is changed according to the block number. And set again.

Next, at step S62, it is determined whether or not printing for one line has been completed. If printing has not been completed, steps S57 to S62 are repeated. When finished,
In step S64, the carriage is stopped, and in step S64
At 65, a line feed is performed.

In the case of bidirectional printing, steps S51, S59 and S60 in the flowchart of FIG. 3 need only be changed as follows. Step S51 Block number ← Block number corresponding to the current carriage position Step S59 Previous block? Step S60 Block number ← Block number -1

In the case where the stepwise change of _Vref at the boundary of the block is abrupt as shown in FIG. 4A and causes noise of the counter pulse A, FIG.
By setting the D / A converter in a plurality of times as described above, the change of _Vref can be made gentle.

Next, a second embodiment for printing according to the present invention will be described with reference to FIG. FIG. 5 is a circuit block diagram of the second embodiment. The circuit shown in FIG. 5 is different from the circuit of the conventional example shown in FIG.
Since other configurations are the same, the following description will be mainly focused on the data selector 122, and the portions related to the other configurations have already been described, and will not be described.

The D / A converter setting data for a plurality of blocks written from the CPU 115 is selected via the data selector 122 according to the selector signal 123 from the counter / timer 113 and set in the D / A converter 114. Thereby, the setting according to the carriage position of _Vref can be performed without increasing the load of software, that is, in steps S51 to S52 and steps S58 to S61 in the printing flowchart for one line in FIG.
This can be performed in the same flowchart as the conventional example except for the above.

As an initial state before the printing operation, the digital data of _Vref in each block obtained in the embodiment of FIG. 1 is preset in the data selector 122 before the printing operation, and each of the carriage position counter data is set. The upper few bits corresponding to the block are used as the selector signal 123 from the counter / timer 113 to the data selector 122.
, The counter / timer 113 and the data selector 122 are connected in advance. For example, if the number of block divisions is 4, the selector signal 123 may have 2 or 3 bits.

When the carriage moves during the printing operation, the carriage position counter in the counter / timer 113 increases / decreases accordingly, so that the selector signal 122 changes, and V _ref applied to the D / A converter 114 is changed. Digital data 124 is switched by data selector 122. Note that the data selector 122 may be any configuration that can store a plurality of data and select and output one of the data by a selector signal. For example, a dual-port RAM is used as the data selector. The configuration may be such that the selector signal is connected to the address of one of the ports.

Further, as shown in FIG. 4A, when the stepwise change of _Vref at the boundary of the block is abrupt and causes noise of the counter pulse A, D / A
The output 120 of the converter 114 may be input to the comparator 110 through a low-pass filter (not shown).

[0054]

As described above, the software for measuring and storing the reference voltage V _ref according to the carriage position in advance and the reference voltage V _ref stored according to the carriage position during the printing operation are provided in real time. By providing the software or hardware to be selected in the above, even if the DC component of the output of the differential amplifier input to the comparator greatly changes due to the carriage position, the output of the comparator can be excellent over the entire moving range of the carriage. Thus, the accuracy of detecting the position of the carriage is improved, and the quality of the print result of the serial printer can be improved.

Further, since the waveform of the counter pulse can be made close to an ideal waveform having a duty ratio of 50%, there is a large margin for the temporal change of the output of the differential amplifier.
Therefore, the degree of deterioration of print quality over time can be reduced. This means that the frequency of executing the sequence of the initial adjustment of the reference voltage _Vref may be reduced, and the user's feeling of use is improved.

[Brief description of the drawings]

FIG. 1 is a flowchart of an initial adjustment sequence of a comparator reference voltage in a first embodiment of a serial printer of the present invention.

FIG. 2 is a timing chart showing a relationship among a comparator input A ₀ , a reference voltage V _ref , and a comparator output A with respect to a carriage position according to the first embodiment.

FIG. 3 is a flowchart illustrating a print sequence for one line according to the first embodiment.

FIG. 4 is a timing chart for explaining a method for reducing the amount of change in the reference voltage _Vref in the first embodiment.

FIG. 5 is a block diagram showing a circuit configuration example of a second embodiment for printing.

FIG. 6 is a perspective view of a main part of the serial printer.

FIG. 7 is a block diagram of a circuit configuration example of a conventional example.

FIG. 8 is a flowchart illustrating a sequence of an initial adjustment of a reference voltage _{Vref according to} a conventional example.

FIG. 9 is a timing chart showing a waveform of a counter pulse when the sampling cycle of the conventional example is an integral multiple of the cycle of the input signal of the comparator.

FIG. 10 is a timing chart showing changes in the duty ratio and edge position of a counter pulse when a relative shift occurs between the input signal of the comparator of the related art and the reference voltage.

FIG. 11 is a flowchart of a reference voltage initial adjustment sequence of the prior application.

FIG. 12 is a timing chart showing the synchronization timing of the prior application.

FIG. 13 is a timing chart showing the relationship between the input signal of the comparator, the reference voltage, and the output signal of the comparator with respect to the carriage position in the conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Carriage 2 Recording part 3 Guide shaft 4 Platen 5 Recording sheet 6 Magnetic linear encoder scale part 7 Main body 8 Flexible substrate 9 Contact part 10 Flexible cable 101 Detecting part 102, 103 MR element 104 Carriage substrate 105, 106 Constant current circuit 107 Differential amplifier 108 Output signal A ₀ 109 Printer control circuit board 110 Comparator 111 Counter pulse 112 A / D converter 113 Counter / timer 114 D / A converter 115 CPU 116 EEPROM 117 ROM 118 RAM 119 CPU bus 120 Reference voltage V _ref 122 Data selector 123 Selector signal 124 D / A converter

Claims (12)

(57) [Claims] 1. A serial printer device which reciprocates on an apparatus main body and performs recording by a recording unit while synchronizing with movement of a carriage on which the recording unit is mounted, wherein a scale of a linear encoder provided on the apparatus main body is provided. And a detection unit of a linear encoder mounted on the carriage to detect the position of the scale unit. A signal output from the detection unit is received as an input signal, compared with a reference voltage, and pulsed as a synchronization signal. Synchronous signal generating circuit means for generating a waveform output signal, and reference voltage initial adjusting means for initially adjusting the reference voltage input to the synchronous signal generating circuit means, wherein the reference voltage initial adjusting means comprises: Moving range blocking means for dividing the moving range of the carriage into blocks, and block dividing by the moving range blocking means Serial printer, characterized in that it comprises a reference voltage calculating means for calculating a reference voltage for each block that. 2. The serial printer according to claim 1, further comprising speed control means for controlling the speed of the carriage before the moving range of the carriage is divided into blocks by the moving range blocking means. Printer. 3. A serial printer according to claim 2, wherein said speed control means comprises speed synchronization means for synchronizing a moving speed of said carriage and a sampling period for sampling said output signal. 4. The serial printer according to claim 3, wherein said speed synchronizing means _sets T _S = T _S0 between the output signal period T _A0 , the sampling period T _S , and the number of measurements n.
T _A0 / 2 ^m (m is an integer of 1 or more), n = k · 2 ^m (where m is the same as m in the preceding expression, and k is an integer of 1 or more). A serial printer, comprising: 5. The serial printer according to claim 1, wherein the reference voltage calculating means measures a value of the output signal a predetermined number of times for each block based on sampling, and comprises: Means for obtaining a reference voltage by averaging the obtained values by the number of samplings. 6. The serial printer according to claim 5, further comprising storage means for storing the obtained reference voltage. 7. The serial printer according to claim 1, further comprising printing means for printing one line based on a reference voltage for each block. 8. The serial printer according to claim 7, further comprising storage means for storing a reference voltage for each block calculated by said reference voltage calculation means, wherein said printing means detects a carriage position. Position detecting means, block determining means for determining which block has a carriage based on the position detected by the carriage position detecting means, and the reference corresponding to the block determined by the block determining means for each block. A reference voltage setting means for reading and setting a voltage from the storage means; and printing using a reference voltage set by the reference voltage setting means for each block. 9. The serial printer according to claim 8, wherein said reference voltage setting means comprises: a block number initializing means for initializing a block number; a block number incrementing means for incrementing a block number; Means for reading out and setting a reference voltage from the storage means every time the block number is incremented based on the serial number. 10. A serial printer according to claim 8, wherein said reference voltage setting means receives a selector signal indicating a carriage position and reads and outputs a reference voltage from said storage means based on said selector signal. A serial printer comprising a circuit. 11. The serial printer according to claim 7, wherein a carriage is set at a predetermined speed before printing by said printing means. 12. A serial printer according to claim 1, wherein said reference voltage obtained from said reference voltage initial adjusting means is D / A converted and input to a comparing means of said synchronization signal generating circuit. A serial printer further comprising a converter.