JP3527985B2 - Print head control method - Google Patents

Description

Detailed Description of the Invention

[0001]

[Industrial applications]

According to the present invention, a motion sensor for monitoring the motion of an armature is provided inside a wire dot print head, the thickness of a print medium is discriminated from the sensor data output from this motion sensor, and the head gap corresponding to this medium thickness is determined. The present invention relates to a method for controlling a wire dot print head for setting the.

[Prior art]

An impact printer, in which a print wire strikes a print medium via an ink ribbon to transfer ink to the print medium for printing, has a high degree of freedom in the print medium and is relatively inexpensive. Therefore, from the past,
It is used in various fields including output devices such as information systems. The impact printer is classified into a plunger type, a spring charge type, and a clapper type according to the type of the wire dot print head.

Among them, in the spring charge type, an armature to which a printing wire is fixed is swingably supported by a bias leaf spring, and the armature is previously resisted against the elastic force of the bias leaf spring. In the state where the spring energy is stored in the spring, it is attracted to the core by the permanent magnet, and when printing, the coil wound around the core is excited to generate a magnetic flux in the opposite direction to the permanent magnet,
Although it has a structure for releasing the above-mentioned armature, in recent years, high-speed printing has been demanded, and this spring charge type wire dot print head which is excellent in high-speed response is often adopted. In addition, recently, a motion sensor is provided inside the head, the motion of the armature is detected by this sensor, and the drive time of the coil is controlled according to the detection result to achieve high-quality printing, or by the sensor. Detects the gap between the print medium and print wire,
A method for achieving high-quality printing by setting the optimum head gap, and detecting the type of print medium, for example, single paper or copy paper, and setting the head gap corresponding to these and setting the print wire drive status A method of performing high-quality printing by setting settings has been proposed.

FIG. 7 is a partial sectional view showing the structure of the wire dot print head. In the figure, reference numeral 1 is a base, and a space yoke 2, a permanent magnet 3, and an end portion on the base 1.
The magnet yoke 4 and the spacer 5 are sequentially stacked,
A leaf spring 7 having an armature 6 fixed thereto is supported on the spacer 5 in a cantilevered manner, and further, an armature yoke 8, a stopper plate 9 and a sensor circuit board 10 are stacked on the leaf spring 7 and guided by the guide. Frame 1
By covering with 1 and fixing with clamp spring 12,
It is one.

Reference numeral 13 denotes a core fixed at a position corresponding to the armature 6 on the base 1, and 14 is a coil wound around the outer periphery of the core 13 via a coil bobbin 15. The core 13, the coil 14, and the coil bobbin 15 are provided. To form an electromagnet. 16 is a thermistor that detects the temperature inside the head in order to prevent the coil from burning.
Reference numeral 17 denotes a drive circuit board which is wired by soldering to the terminals output from the coil 14 and the thermistor 16, and 18 is a heat sink cap which protects the drive circuit board 17 and enhances the heat radiation effect.

The armature 6 is attached to the flexible portion of the leaf spring 7 so as to be adjacent to the armature yoke 8.
A print wire 19 is attached to the tip of the armature 6, and the tip of the print wire 19 is guided to a platen side (not shown) by a wire guide 21 fixed to a guide nose 20. In the above configuration, in the non-printing state, the armature 6 bends the leaf spring 7 against the leaf spring 7 to store the spring energy, and the permanent magnet 3
Is attracted to the core 13 by the magnetic flux generated by.

At the time of printing, the core 13 and the coil 1
4, the electromagnet composed of the coil bobbin 15 is driven to generate a magnetic flux in a direction in which the magnetic flux of the permanent magnet 3 is cancelled, so that the leaf spring 7 in the biased state is released, and is fixed to the armature 6 by the stored spring energy. The printed wire 19 hits the print medium through an ink ribbon (not shown) to print. Here, 22 is a sensor electrode attached at a position facing the armature 6 on the sensor circuit board 10, and 23 is this sensor electrode 22.
The sensor LSI for processing the output signal of the above and outputting it to the control means (not shown) constitutes an operation sensor for detecting the operation of the armature 6 and the print wire 19 fixed to the armature 6 from these configurations.

That is, by providing a narrow space between the sensor electrode 22 and the armature 6, a capacitor having a capacitance C that changes according to the distance between the sensor electrode 22 and the armature 6 is formed. However, when the armature 6 is displaced during the printing operation, the electrostatic capacitance C also changes. Therefore, the electrostatic capacitance C is detected by the sensor LSI 23, arithmetic processing is performed, and output to the control means (not shown). The operating state of the print wire 19 fixed to the armature 6 can be known.

That is, FIG. 8 is a graph showing a general example of the waveform obtained by the motion sensor from the output of the sensor electrode 22. By subjecting the output of the sensor electrode 22 to a predetermined calculation process in the sensor LSI 23, This is shown in Figure 8 for the motion sensor.
A waveform a as shown in is obtained. In FIG. 8, the horizontal axis represents the passage of time, and the vertical axis represents the generated voltage which is the sensor output data. By comparing this waveform a with the predetermined slice levels SL1 and SL2 in the sensor LSI 23, the peak of the waveform is obtained. , V1, V2, and the times T1, T2, T3, etc. until the intersection with this slice level are obtained, but these values are within a certain range of variation.

Here, the generated voltage is the armature 6
Which is almost equal to the speed of
1 is the time from the driving of the coil 14 until the armature 6 starts to move (release time), and T2 is the time from the movement of the armature 6 until the print wire 19 collides with the platen or print medium via the ink ribbon ( (Flight time), T3 indicates the time (return time) until the armature 6 is returned to the core 13 after being sucked.

[0012] Here, two slice data are set in order to obtain the above-mentioned data. However, by increasing the number of slice levels, the sensor output data obtained increases, and a more detailed armature is obtained. 6. The operating state of the print wire 19 can be known. FIG. 9 is a graph showing the difference in waveforms when the print media have different thicknesses. When the print head is at the same position, the print medium with the smaller thickness is between the tip of the print wire and the print medium. Since the gap between the two becomes wider and the stroke of the printing wire increases, the waveform obtained by the motion sensor is delayed when the medium thickness is thinner than when the medium thickness is thick. For example, in the case of four sheets (copy paper), the waveform b as shown by the solid line is obtained, and in the case of a thin print medium, for example, one sheet (single sheet),
A waveform c as shown by a broken line is obtained.

When the sensor LSI 23 compares the slice levels SL1 and SL2 with the waveform b or the waveform c, the release time T1 (1
P), flight time T2 (1P), return time T3 (1P),
Alternatively, when the print medium is thick, the release time T1 (4
P), flight time T2 (4P), and return time T3 (4P). At this time, the total of the release time T1 (1P) and the flight time T2 (1P) is the print time T1 + 2 for one sheet.
(1P), release time T1 (4P) and flight time T2 (4
The total of P) is the print time T1 + 2 (4
P), the waveform c lags the waveform b as described above, so T1 + 2 (1P)> T1 + 2 (4P), T3
(1P)> T3 (4P).

Taking advantage of this, in advance there is no print medium or a medium having a specified thickness is used,
The reference release time T1n, flight time T2n, and return time T3n are obtained, the thickness of the print medium is determined by comparison with these, and the print head is moved according to this medium thickness to form the optimum head gap. Is designed to
This is called an auto gap operation.

Here, FIG. 10 is a graph showing the difference in waveform due to aging. In the initial state where the movable portion of the print head is not worn, the waveform d shown by the solid line is obtained.
At this time, the release time T1 is used as the sensor output data.
a, the flight time T2a, the return time T3a, and the generated voltages V1a and V2a are obtained. Further, when the print head is operated near the end of its life, the stroke of the print wire 19 with respect to the platen or the medium of the specified medium thickness increases due to wear of the armature suction point of the core 13 or wear of the print head holding mechanism. A waveform e as shown by a broken line is obtained. At this time, the release time T1b, the flight time T2b, the return time T3 are used as the sensor output data.
b, and the generated voltages V1b and V2b are obtained.

Comparing the case where the print head is in the initial state of operation and the case where the print head is in the state of being operated near the end of its life, T1a = T1b, T2a≤T2b, T3a
There is a tendency that ≦ T3b, V1a ≦ V1b, V2a ≦ V2b. During the auto gap operation described above, the release time, flight time, and return time obtained in advance with no print medium or using a medium with a specified thickness, and the release obtained when there is a medium to be printed The media thickness is determined by comparing the time, flight time, and return time, but as described above, when the print head is in the initial state of operation and when it is in the state of operating near the end of its life,
Since the release time, flight time, and return time are different, it is necessary to match the reference release time, flight time, and return time with the state of the print head. Therefore, for example, when there is no print medium after power is turned on. Alternatively, the release time, flight time, and return time are calculated using a medium with a specified thickness,
An operation of storing this is performed, which is called a self-adjusting operation.

FIG. 11 is a flowchart showing a conventional control method for the wire dot print head described above. First,
When the power is turned on (SA1), it is determined whether or not the print medium is at the print position (SA2). When it is determined in SA2 that the print medium is not at the print position, the coil 14 is used to detect the sensor data such as the release time, the flight time, the return time, and the generated voltage, which are the references during the automatic gap operation. Is driven to perform printing in a predetermined pattern, sensor data indicating the operation state of each armature 6 is detected from the output of the operation sensor at that time (SA3), and the sensor data for each print wire is stored in the backup memory. (SA4). It should be noted that this series of operations is referred to as a self-adjusting operation as described above.

Then, it is judged whether or not the print medium is newly set at the print position (SA5), and if it is judged at SA5 that the print medium is not newly set at the print position, the print medium is set. Wait for If it is determined at SA5 that the print medium is newly set at the print position, or if it is determined at SA2 that the print medium is at the print position, the printing point on the first print line after receiving the print data Among them, an arbitrary dot is selected, the coil 14 is driven so that the print wire 19 corresponding to this dot moves, and test printing is performed, and the sensor data at this time is detected (SA6).

By comparing the sensor data detected in SA6 with the sensor data stored in SA4, the thickness of the print medium is determined (SA7), and the optimum head gap is obtained according to this medium thickness. The print head is moved so as to be driven, and drive conditions such as a time for energizing the coil are set (SA8). Then, normally, printing is performed under the conditions set in SA8 (SA9).

As described above, by performing the self-adjusting operation after the power is turned on, it is possible to correct the change with time of the sensor data, which is the reference of the automatic gap, due to the abrasion of the movable portion of the print head.

[Problems to be Solved by the Invention]

FIG. 12 shows a high frequency of use in European and American ANK systems.
It is an explanatory view showing the arrangement of the print wires in the present wire dot print head. With such a print head, the diameter d of the print wires 19 is about 0.3 to 0.34 mm, and the pitch P between the wires is 1/72. ″ = 0.353 mm, and the distance between the wires is very narrow.
Therefore, as printing is continued, the ink penetrates between the wires due to surface tension from an ink ribbon (not shown) and adheres between the wires.

In this way, if the ink penetrates and adheres between the wires, the viscosity of the oil in the ink rises at a low temperature after the printing operation is stopped for a while, and the printing wire 19 jumps out or returns. However, the load may be adversely affected by the self-adjustment operation or the auto gap operation. That is, FIG. 13 is a graph showing the difference in waveform between the case where ink is attached between the wires and the case where ink is not attached. If the waveform f shown by the solid line is the case where ink is not attached, the ink When the ink is attached, the waveform g shown by a broken line is delayed from the waveform f, and the release time T when the ink is attached is shown.
1 ', flight time T2', and return time T3 'are longer than release time T1, flight time T2, and return time T3 when ink is not adhered.

As a result, when the auto gap operation is performed, even if the release time, the flight time, and the return time are long, it may be long due to the thin medium thickness, or there may be a delay due to the ink load. It is not possible to determine whether it has become longer, and even if it becomes longer due to the ink load, the medium thickness is simply determined as being thin, so it is not possible to accurately determine the medium thickness, and inaccurate auto gap operation There is a problem that you may do.

If the difference between the release time, the flight time, and the return time, which are the reference, and the release time, the flight time, and the return time obtained during the automatic gap operation is large, the print wire is broken and the stroke of the print wire is broken. It is conceivable that these times have become longer due to the extension of, etc. Therefore, when the specified range is exceeded, an alarm is issued and operation is stopped. However, FIG.
As described above, when the print head is operated for a long time, the release time, flight time, and return time tend to be longer than in the initial state. In this state, the sensor output when ink adheres between the print wires From the data, a waveform h as shown by the one-dot chain line in FIG. 10 is obtained, but the release time T1c, the flight time T2c, and the return time T3c are further lengthened due to the ink load, which exceeds the specified range. May cause an alarm.

Even in this case, the print head itself can operate normally, but when an alarm occurs, the operation must be stopped in order to respond to this, and an erroneous alarm is issued, resulting in operational efficiency. There is a problem that it gets worse. Further, FIG. 14 is an explanatory diagram showing the force applied to the print wire. As shown in FIG. 14A, when the armature 6 to which the print wire 19 is fixed is sucked by the core 13, the tip of the print wire 19 is a wire. Guide hole 2
Since it is guided by 1a, a force F in the direction indicated by the arrow acts on the printing wire 19.

Therefore, in the case of a 9-wire print head having a structure in which the tips of the print wires 19 are arranged in one row,
As shown in FIGS. 14B and 14C, when the print wires 19 are on both sides, the print wire 19a at the center is the print wire 19a when the print wires 19b and 19c on both sides are sucked.
The lateral pressure F is received from b and 19c. At this time, if the print wire 19a in the center flies for a hit point, as shown in FIG.
As shown in FIG. 2, since the print wires 19b and 19c are separated from the print wires 19b and 19c on both sides, the distance between the print wires 19b and 19c is narrowed. Wire 19b, 1
The printing wires 19b, 1 against the side pressure F received from 9c.
It interrupts during 9c and becomes a load of the return operation.

Therefore, if the ink adheres between the adjacent print wires 19 as described above, the output of the operation sensor is more likely to be delayed due to an increase in the load due to an increase in the viscosity of the ink at a low temperature. However, there is a problem in that the instability of the auto gap and the possibility of erroneously issuing an alarm increase. As described above, according to the present invention, since the distance between the adjacent print wires is narrow, the ink intrudes and adheres between the print wires, which becomes a load during the operation of the print wires and causes a delay in the operation of the print wires. When performing the automatic gap operation by determining the thickness of the print medium based on the operating state of the wire, there is the problem that an accurate gap cannot be set, and wear on the moving parts due to long-term use of the print head. , If the print wire has a longer flight distance, and if the print wire operation is delayed due to the ink load between the print wires as described above, the delay will exceed the specified range and an alarm will be issued erroneously. It was made to solve the problem of issuing.

That is, before the self-adjustment operation and the automatic gap operation, the viscosity of the ink between the print wires is reduced so that the operation of the print wires is not delayed and an appropriate gap can be set. An object is to provide a method for controlling a wire dot print head.
In addition, during the self-adjustment operation, the presence or absence of the influence of the ink load between the print wires is determined, and if abnormal data due to the influence of the ink load is output, this is invalidated and compared during the auto gap operation. To provide a control method of a wire dot print head capable of setting a proper gap by enabling stable auto gap operation without erroneously issuing an alarm by storing sensor data suitable for being used as a reference of With the goal.

Further, at the time of the automatic gap operation, by driving the print wire at a position where it is unlikely to be influenced by the adjacent print wires, and by determining the medium thickness from the sensor output data indicating the operation state of this print wire, An object of the present invention is to provide a method for controlling a wire dot print head capable of setting an appropriate gap without being affected by ink attached between print wires.

[Means for Solving the Problems]

In order to achieve this object, the present invention is a wire dot in which the print wire is moved to strike the print medium via the ink ribbon at the tip of the print wire, and the force is used to transfer the ink for printing. The print head is provided with an operation sensor for detecting the operation state of the print wire, and a self-adjusting operation for detecting output data of the operation sensor in the absence of a print medium and storing the output data as reference data,
A wire that detects the output data of the motion sensor in the presence of the print medium, compares the output data with the reference data to determine the thickness of the print medium, and performs an auto gap operation for forming a head gap according to the medium thickness. In the dot print head control method, the presence or absence of a print medium is determined, and if there is no print medium, a self-adjustment is performed after a warm-up operation of moving the print wire in a stroke that does not hit the platen. The operation is performed, and when there is a print medium, the automatic gap operation is performed after performing a warm-up operation of moving the print wire in a stroke such that the print wire does not hit the print medium.

It should be noted that the operation frequency of the print wire during the warm-up operation may be changed. Further, according to the present invention, it is determined for each wire whether the sensor output data obtained during the self-adjustment operation is within a specified range, and if the sensor output data of all the printing wires is normal, each wire is detected. The sensor output data obtained in this self-adjustment operation is stored as reference data.If the sensor output data of a certain number or more of printing wires is abnormal, the previous sensor output data for each wire is self-adjusted this time. It is characterized by being stored again as the reference data obtained by the operation.

[Action]

According to the present invention described above, the presence or absence of the print medium is discriminated after the power is turned on, and when there is no print medium, the warm-up operation of moving the print wire in a stroke such that the print wire does not hit the platen is performed. When there is a print medium, the print wire is warmed up with a stroke so that the print wire does not hit the print medium, and after such warm-up operation, self-adjustment operation or auto gap operation is performed. I do.

Further, it is discriminated for each wire whether the sensor output data obtained during the self-adjusting operation is within a prescribed range. If the sensor output data of a predetermined number or more of printing wires is abnormal, this is detected. It is judged that abnormal data has appeared due to the influence of the ink adhering between the print wires,
Without issuing an alarm, the sensor output data obtained by this self-adjustment operation is invalidated, the previous sensor output data is re-stored, and this is used as reference data.

Further, during the automatic gap operation, in the print wires whose tips are arranged in a line, both or one of the print wires located at both ends which is not affected by the ink adhering between the print wires is moved. The sensor output data is obtained by comparing with the reference data to determine the thickness of the print medium, and the head gap corresponding to the medium thickness is formed. Also, during the automatic gap operation, move the print wire containing print data with the print medium,
The output data of the motion sensor at this time is detected, and this is compared with the reference data to determine the thickness of the print medium, and when the head gap corresponding to this medium thickness is formed, the position of the print head is the same as the previous time. If they are the same, and if the print head position is different from the previous time, the print medium is conveyed so that either or both of the print wires at both ends can print the spot on the print medium. The sensor output data is obtained by moving one or both of the print wires corresponding to the spot to be printed on the print medium, and by comparing this with the reference data, the thickness of the print medium is determined, and the head corresponding to this medium thickness is obtained. Form a gap.

【Example】

Embodiments will be described below with reference to the drawings.
FIG. 1 is a flow chart showing a method for controlling a wire dot print head according to the first embodiment of the present invention. The structure of the print head is the same as that described with reference to FIG. 7 described above, and a description thereof will be omitted here.

First, when the power is turned on (SB1), it is determined whether the print medium is at the print position (SB2).
When it is determined in SB2 that the print medium is not at the print position, the coil 14 is driven to print a predetermined warm-up pattern, thereby performing the warm-up operation of moving the print wire 19. In this warm-up operation, the drive time of the coil 14 is set so that the print wire 19 does not collide with the platen (SB3).

After performing the warm-up operation at SB3, the self-adjustment operation is performed. That is, in order to detect the sensor data such as the above-mentioned release time, flight time, return time, generated voltage, etc., which serve as a reference during the automatic gap operation, the coil 14 is driven and printing is performed in a predetermined pattern, and the operation at that time is performed. Sensor data indicating the operating state of each armature 6 is detected from the output of the sensor (SB4), and the sensor data for each print wire is stored in the backup memory (SB5).

Then, it is determined whether or not the print medium is newly set at the print position (SB6), and if it is determined at SB6 that the print medium is not newly set at the print position, the print medium is set. Wait for When it is determined at SB6 that the print medium is newly set at the print position, or when it is determined at SB2 that the print medium is at the print position, the coil 14 is driven to set a predetermined warm-up pattern. By printing, the warm-up operation of moving the print wire 19 is performed. In this warm-up operation, the print wire 1
The drive time of the coil 14 is set so that 9 does not collide with the print medium (SB7).

After performing the warm-up operation at SB7, the auto gap operation is performed. That is, after receiving the print data, an arbitrary dot is selected from the dots on the first print line, the coil 14 is driven so that the print wire 19 corresponding to this dot moves, and the trial printing is performed. The sensor data of is detected (SB8). SB8 above
The thickness of the print medium is determined by comparing the sensor data detected in step S7 with the sensor data stored in step SB7 (SB9), and the print head is adjusted so that an optimum head gap can be obtained according to this medium thickness. While moving
Set drive conditions such as the time to energize the coil (S
B10).

Then, normally, printing is performed under the conditions set in SB10 (SB11). In this way, by performing the self-adjusting operation after the power is turned on, it is possible to correct the change with time of the sensor data, which is the reference of the auto gap, due to wear of the print head movable portion. Normally, the self-adjustment operation or the auto gap operation is performed in a state where the printing operation is stopped for a while, the print head is cooled, and the viscosity of the ink adhered between the print wires is increased. By performing a warm-up operation for moving the print wire before performing the auto gap operation, it is possible to reduce the load of ink during the print wire operation in the self-adjustment operation or the auto gap operation.

Here, FIG. 2 is an explanatory view showing the concept for determining the stroke of the print wire in the warm-up operation described above, and the maximum adjustment that can be made by moving the print head 24 in the direction away from the platen 25. When the head gap is GH and the print medium 26 having the maximum thickness P is at the print position, the gap GL = GH.
-P. Therefore, during the warm-up operation, the print head 24 is moved to the farthest position from the platen 25, and in the warm-up operation described in SB3 of FIG. The drive time of the coil 14 is set so that a stroke slightly shorter than the maximum gap GH described above is obtained so that the ink of the ink ribbon 27 is not transferred by colliding with the print head, and the printing described in SB7 of FIG. 1 is performed. In the warm-up operation when there is a medium, the maximum gap G in the case where there is a print medium having the above-mentioned maximum thickness so that the print wire 19 does not collide with the print medium 26 and transfer the ink of the ink ribbon 27.
Coil 14 so that a stroke slightly shorter than L can be obtained
By setting the drive time for the print wire 19, the print wire 19 does not collide with the platen 25 or the print medium 26, and the warm-up operation is performed with a large stroke of the print wire in both the case where the print medium is not present and the case where the print medium is present. The maximum effect is improved.

Further, although there are a plurality of printing wires, the load due to ink adhesion is larger in the printing wire located in the center, so during warm-up operation, a pattern is printed such that the printing wire located in the center moves a lot. The coil 14 is driven as described above. FIG. 3 is a flow chart showing a method of controlling the wire dot print head in the second embodiment of the present invention.

Since the structure of the print head is the same as that described with reference to FIG. 7, the description thereof will be omitted here. Further, in the print head of the present embodiment, the tips of the print wires 19 are arranged in a line, for example, like the print head of 9 wires described in FIG. Here, in the wire dot print head having the arrangement in which the print wires are adjacent to each other as described with reference to FIG. 12, the ink penetrates and adheres between the adjacent print wires 19 as the number of printing operations increases. And
At low temperatures, such as after the printing operation has stopped for a while, the viscosity of the ink adhering between the printing wires increases, which becomes a load during the operation of the printing wires.

As described above, when the self-adjusting operation is performed after the printing operation is stopped for a while, the viscosity of the ink adhering between the printing wires rises and becomes a load,
The operation of the print head is delayed. Also, when the print head is used for a long period of time and the moving parts become worn,
The stroke of the print wire 19 becomes long, and at this time, the motion sensor obtains a waveform h as shown by the one-dot chain line in FIG. 10. This waveform h is compared with the waveform d obtained in the initial state of the print head. There is a large delay, and the sensor data obtained from this waveform h has a certain release time T1c and flight time T.
2c, the return time T3c goes out of the predetermined standard range, and if the sensor data goes out of the predetermined standard range, an alarm is issued and the operation is stopped.

At this time, the print head itself has no abnormality other than the ink load, and the ink load is reduced by operating the print wire. Therefore, during the self-adjusting operation, the sensor data exceeding the specified range may be detected. If there are many print wires that have been output, it is determined that there was a delay in the operation of the print wires due to the effect of ink adhesion. In this case, the sensor data obtained last time is used during the auto gap operation. It is a thing.

The second embodiment will be described below with reference to FIG. 3. When the power is turned on and there is no print medium, the self-adjustment operation is performed. That is, the release time, flight time, return time, and
In order to detect sensor data such as generated voltage, coil 1
4 is driven to perform printing in a predetermined pattern, and sensor data indicating the operating state of each armature 6 is detected from the output of the operating sensor at that time (SC1).

Then, of the sensor data detected for each print wire, it is determined whether or not there is a print wire with abnormal data outside the specified range (SC2). If it is determined in SC2 that there is no abnormal data print wire outside the specified range, the sensor data for each print wire is stored in the backup memory (SC3). If it is determined in SC2 that there is a print wire with abnormal data outside the specified range, it is determined whether the number of wires is equal to or greater than a preset specified number n (SC4). The specified number n is preferably 2 or more.

If it is determined in SC4 that the number of print wires that output abnormal data is equal to or greater than the specified number n, it is determined that this abnormal data is due to the load of ink adhering between the print wires, and all the data obtained this time. The sensor output data is invalidated, and the sensor data for each print wire obtained during the previous self-adjustment operation is stored again in the backup memory without stopping the operation (SC5).

If it is determined in SC4 that the number of print wires that output abnormal data is less than the specified number n, it is determined that the abnormal data is due to an abnormality in the print wires themselves, such as when the print wires are broken. The sensor data for each print wire is invalidated and the remaining sensor data is valid, and the sensor data for each of the remaining print wires obtained this time is stored in the backup memory (SC6).

Then, the self-adjusting operation is performed in the above-described procedure to store the sensor data such as the release time, the flight time, the return time, and the generated voltage, which are the reference during the automatic gap operation, and then the print medium is set. Then, the auto gap operation is performed. FIG. 4 is a flow chart showing a method for controlling the wire dot print head in the third embodiment of the present invention.

Since the structure of the print head is the same as that described with reference to FIG. 7, the description thereof will be omitted here. Further, in the print head of the present embodiment, the tips of the print wires 19 are arranged in a line, for example, like the print head of 9 wires described in FIG. Here, as described in FIG.
In the wire dot print head in which the print wires are arranged adjacent to each other, the ink penetrates and adheres between the adjacent print wires 19 as the number of printing operations increases.

At a low temperature such as after the printing operation is stopped for a while, the viscosity of the ink adhering between the printing wires increases, which becomes a load during the printing wire operation. In the print head of the wire, the NO. No. 1 printing wire 19 or NO. The print wires 19 of No. 9 have adjacent print wires on only one side, and therefore are less affected by the load of ink adhering between the print wires.

When there are print wires at both ends of the print wire, the print wire 19a located at the center is the print wire 19 at both ends as described with reference to FIGS. 14 (b) to 14 (d).
The lateral pressures from b and 19c act as a load during operation, but the NO. 1 or NO. In the print wire of No. 9, since the adjacent print wires exist only on one side, as shown in FIG. 1 or NO. The print wires 19d of 9 are the adjacent print wires 1
When the side pressure F from 9e is received, it is possible to escape in the direction of the arrow a, so that the print wires at both ends are not affected by the side pressure from the adjacent print wires.

In this way, in the print head in which the tips of the print wires 19 are arranged in a line, such as the print head of 9 wires, the print wires 1 at both ends thereof are arranged.
The operation of 9 is stable, and the output of the operation sensor corresponding to the print wires 19 at both ends is also stable. The control method in the third embodiment will be described below. When the print medium is set to the print position (SD1), the print wires 19 whose ends are arranged in a line are print wires located at both ends of the print wire 19, for example, the print head of 9 wires described in FIG. And NO. No. 1 printing wire 19 and NO. Either one or both of the print wires 19 of No. 9 conveys the print medium so that the spot to be printed on the print medium can be spotted (SD2). 1 printing wire 1
9 and NO. In order to move either one or both of the nine print wires 19, the corresponding coil 14 is driven for a predetermined time.

As a result, the armature 6 starts to move due to the spring energy stored in the leaf spring 7, and NO.
No. 1 printing wire 19 and NO. Test printing is performed with one or both of the printing wires 19 of No. 9, and after this printing, the core 13 of the armature 6 is sucked (SD
3). The operation state of the print wire 19 by the series of operations described above, that is, the release time which is the time from the driving of the coil 14 to the start of movement of the armature 6, the print wire 19 from the start of movement of the armature 6 through the ink ribbon. The flight time, which is the time until the print medium collides with the print medium, and the return time, which is the time until the armature 6 is returned by being sucked by the core 13, are detected as the output data of the motion sensor (SD4). For example, the reference sensor output data obtained and stored by performing the self-adjustment operation after the warm-up operation described in the first embodiment or the self-adjustment operation described in the second embodiment. The thickness of the print medium is determined by comparing the obtained and stored reference sensor output data (S 5) determining the amount of movement of such print heads as optimum head gap is formed between the printing wire tip and the indicia shaped medium according to the thickness of the printing medium (SD6).

Then, a mechanism (not shown) is driven to move the print head by the amount of movement determined according to the thickness of the print medium to form an optimum head gap between the tip of the print wire 19 and the print medium. (SD7), usually SD7 above
Printing is performed with the head gap set in (SD8). In this way, the print wires at both ends of the print wires arranged in a line are not affected by the ink adhering between the print wires and by the lateral pressure from the print wires on both sides of the print wire. It is possible to accurately determine the thickness and form the optimum head gap.

FIG. 5 is a flow chart showing a control method of the wire dot print head in the fourth embodiment of the present invention.
FIG. 6 is an explanatory diagram showing the positional relationship between the print wire and the print medium in the fourth embodiment. First, when the print medium 26 is set at the print position (SE1), the print wire 19 having print data, for example, the print head of 9 wires described in FIG. 4, NO. 5 and NO.
The corresponding coil 1 to move the print wire 19 of 6
4 is driven for a predetermined time (SE2).

As a result, the armature 6 begins to move due to the spring energy stored in the leaf spring 7, and NO.
4, NO. 5 and NO. The test wire 6 is used for trial printing, and after this printing, the armature 6 is attracted to the core 13. The operating state of the print wire 19 by the series of operations described above, that is, the release time which is the time from the driving of the coil 14 to the start of movement of the armature 6, the print wire 1 from the start of movement of the armature 6
The flight time, which is the time until 9 collides with the print medium via the ink ribbon, and the return time, which is the time until the armature 6 returns after being sucked by the core 13, are detected as the output data of the motion sensor (SE3. ), The sensor output data and, for example, the reference sensor output data obtained by performing the self-adjustment operation after the warm-up operation described in the first embodiment and stored, or the second embodiment. By comparing the reference sensor output data obtained and stored by the self-adjusting operation described above, the thickness of the printing medium is determined (SE4), and the tip of the printing wire and the printing are determined according to the thickness of the printing medium. An amount of movement of the print head is determined so that an optimum head gap is formed between the medium and the medium (SE5).

Then, the position of the print head when the print head is moved by the amount of movement obtained this time is compared with the position of the print head stored in the previous auto gap operation, and it is determined whether or not this is the same. Determine (SE
6). This is a typical printer usage,
The same print medium is often used, and the medium thickness does not change. Thus, in SE6, the position of the print head when the print head is moved by the movement amount obtained this time is compared with the position of the print head stored in the previous auto gap operation, and if it is determined that this is different, The ink attached between the print wires becomes a load, which affects the operation of the print wires when determining the medium thickness, and it can be determined that the normal medium thickness cannot be obtained.

That is, the position of the print head when the print head is moved by the amount of movement obtained this time in SE6 is compared with the position of the print head stored in the previous automatic gap operation, and it is found that this is the same. When it is determined, a mechanism (not shown) is driven to move the print head by the amount of movement determined according to the thickness of the print medium, and the print wire 1
An optimum head gap is formed between the tip of the print head 9 and the print medium (SE7), and data indicating the position of the print head at this time is stored in the backup memory (SE8), which is normally set in SE5. Printing is performed with the head gap (SE9).

Further, the position of the print head when the print head is moved by the movement amount obtained this time in SE6 is compared with the position of the print head stored in the previous automatic gap operation, and if it is determined that they are different, , So that either or both of the print wires 19 at both ends can print a spot on the print medium to be printed, as shown in FIG. 1 with printing wire 19
O. The print medium is conveyed so that the print wire 19 of 4 can hit the spot a to be hit (SE10).

Next, NO. In order to move the print wire 19 of No. 1, the corresponding coil 14 is driven for a predetermined time, whereby the armature 6 starts to move due to the spring energy stored in the leaf spring 7, and NO. 1 printing wire 19
At the same time as the test printing, the armature 6 is sucked by the core 13 after this printing (SE11). The operation state of the print wire 19 by the series of operations described above, that is, the release time which is the time from the driving of the coil 14 to the start of movement of the armature 6, the print wire 19 from the start of movement of the armature 6 through the ink ribbon. And the return time, which is the time until the armature 6 returns after being sucked by the core 13 and the like, which is the time until the collision with the print medium is detected as the output data of the motion sensor,
(SE12), this sensor output data and, for example, the reference sensor output data obtained and stored by performing the self-adjusting operation after the warm-up operation described in the first embodiment, or the second execution described above. By comparing the reference sensor output data obtained and stored in the self-adjustment operation described in the example, the thickness of the print medium is determined (SE13), and the tip of the print wire is determined according to the thickness of the print medium. An amount of movement of the print head is calculated so that an optimum head gap is formed between the print medium and the print medium (SE14).

Then, a mechanism (not shown) is driven to move the print head by the amount of movement determined according to the thickness of the print medium to form an optimum head gap between the tip of the print wire 19 and the print medium. At the same time (SE7), data indicating the position of the print head at this time is stored (SE8),
Normally, printing is performed with the head gap set in SE7 (SE9). In addition, in the second embodiment, of the print wires 19 at both ends, the NO. The printing wire 19 of No. 1 was used, but depending on the spot to be printed on the printing medium, N
O. The printing wire 19 of No. 9 may be used, or NO.
1 and NO. Both print wires 19 of 9 may be used.

By combining the above-described embodiments, it is possible to realize a more stable auto gap operation and obtain a proper head gap. For example, by combining the first and second embodiments, the first
If the ink load cannot be sufficiently reduced even after performing the warm-up operation described in the second embodiment, the effect of the ink load is removed by performing the self-adjusting operation described in the second embodiment. Then, the sensor output data that serves as a reference during the automatic gap operation can be obtained.

Further, after the warm-up operation described in the first embodiment is performed, the auto gap operation described in the third and fourth embodiments is performed to reduce the influence of the load of the adhered ink. It can be less. In each of the above-mentioned embodiments, the spring charge type wire dot print head has been described, but it goes without saying that a clapper type wire dot print head is also applicable.

【The invention's effect】

As described above, according to the present invention, the warm-up operation for moving the print wire is performed before the output data of the motion sensor is detected by the self-adjustment operation or the auto gap operation. It is possible to reduce the load on the adhered ink and reduce the influence on the operation of the print wire.
This has the effect that stable sensor output data can be obtained and an accurate auto gap operation can be performed.

Further, during the warm-up operation, the stroke of the print wire is changed depending on the presence or absence of the print medium, so the print medium or the platen can be warmed up with and without the print medium without being contaminated with ink. It has an effect that the effect can be enhanced. Further, since the operation frequency of the print wire is changed during the warm-up operation, it is possible to focus the operation of the print wire that is largely affected by the structurally attached ink, and further improve the warm-up effect. Has the effect.

Further, it is determined for each wire whether the sensor output data obtained during the self-adjustment operation is within a specified range. If the sensor output data of a predetermined number or more of print wires is abnormal, the print wire is detected. It is determined that the sensor output data is abnormal due to the ink that has adhered between them, and the previous sensor output data is re-stored for each wire as the reference data obtained by the self-adjusting operation this time without issuing an alarm. Therefore, it is possible to improve operational efficiency without accidentally issuing an alarm when it is not necessary to issue an alarm that ink is attached between the print wires and stopping the operation. It has the effect that

Further, during the automatic gap operation, in the print wires whose tips are aligned in a line, both or one of the print wires located at both ends which are less susceptible to the ink adhering between the print wires is removed. The sensor output data is obtained by moving it, and this is compared with the reference data to determine the thickness of the print medium, and the head gap is formed according to this medium thickness. This has an effect that an error does not occur and an incorrect auto gap operation is not performed.

Further, the output data of the motion sensor is detected in the state where the print medium is present by the automatic gap operation, and this is compared with the reference data to determine the thickness of the print medium,
When forming the head gap according to this medium thickness, determine whether the position of the print head is the same as the previous time, and if the position of the print head is different from the previous time, the influence of the ink adhering between the print wires The sensor output data is obtained by moving both or one of the print wires located at both ends that are difficult to receive, and comparing this with the reference data to determine the thickness of the print medium, and determine the head gap according to this medium thickness. Since it was decided to form, only when there is an error in the sensor output data due to the influence of the attached ink, move the printing wire that is not easily affected by the attached ink to obtain accurate sensor output data, By comparing this with the reference data to determine the thickness of the print medium and forming the head gap according to this medium thickness, an incorrect auto gap operation is performed. With bets is eliminated, if not affected by ink adhesion of that does not perform the operation, it has the effect that it is possible to increase the processing speed.

[Brief description of drawings]

[0071]

FIG. 1 is a flowchart showing a method of controlling a wire dot print head according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a concept for determining a stroke of a print wire in a warm-up operation.

FIG. 3 is a flowchart showing a method for controlling a wire dot print head according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing a method of controlling a wire dot print head according to a third embodiment of the present invention.

FIG. 5 is a flowchart showing a method of controlling a wire dot print head according to a fourth embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a positional relationship between a print wire and a print medium in a fourth embodiment.

FIG. 7 is a partial cross-sectional view showing the configuration of a wire dot print head.

FIG. 8 is a graph showing a general example of a waveform obtained by a motion sensor.

FIG. 9 is a graph showing a difference in waveform when print media have different thicknesses.

FIG. 10 is a graph showing a difference in waveform due to changes over time.

FIG. 11 is a flowchart showing a conventional method of controlling a wire dot print head.

FIG. 12 is an explanatory diagram showing an arrangement of print wires in a 9-wire dot print head.

FIG. 13 is a graph showing a difference in waveform between the case where ink is attached between the wires and the case where ink is not attached.

FIG. 14 is an explanatory diagram showing a force applied to a print wire.

[Explanation of symbols]

[0072] 6 Armature 13 cores 19 printing wire 22 Sensor electrode 23 Sensor LSI

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Noboru Oishi               1-7 Toranomon, Minato-ku, Tokyo Okiden               Ki Industry Co., Ltd. (72) Inventor Masayuki Ishikawa               1-7 Toranomon, Minato-ku, Tokyo Okiden               Ki Industry Co., Ltd. (72) Inventor Yasuhiko Shimosugi               1-7 Toranomon, Minato-ku, Tokyo Okiden               Ki Industry Co., Ltd. (72) Inventor Koichi Ando               1-7 Toranomon, Minato-ku, Tokyo Okiden               Ki Industry Co., Ltd. (72) Inventor Takanori Mimura               1-7 Toranomon, Minato-ku, Tokyo Okiden               Ki Industry Co., Ltd.                (56) Reference JP-A-4-276477 (JP, A)                 JP-A-3-121860 (JP, A)                 International Publication 89/04766 (WO, A1)

Claims (4)

(57) [Claims] 1. A wire dot print head for striking a print medium through an ink ribbon at the tip of the print wire by moving the print wire, and transferring the ink to perform printing, the operation of the print wire. Equipped with a motion sensor that detects the status, detects the output data of this motion sensor when there is no print medium and stores it as reference data, and detects the output data of the motion sensor when there is a print medium Then, by comparing this with the reference data, the thickness of the print medium is determined, and in the method of controlling the wire dot print head that performs the auto gap operation to form the head gap according to this medium thickness, the presence or absence of the print medium is determined. If there is no print medium, the warm-up that moves the print wire with a stroke that does not hit the platen. After performing the operation, perform the self-adjustment operation, and if there is a print medium, perform the warm-up operation that moves the print wire in a stroke that does not hit the print medium, and then perform the auto gap operation. A control method for a characteristic wire dot print head. 2. The method of controlling a wire dot print head according to claim 1, wherein the frequency of operation of the print wire during warm-up operation is changed. 3. A wire dot print head for striking a print medium through an ink ribbon at the tip of the print wire by moving the print wire, and transferring the ink to print, thereby operating the print wire. Equipped with a motion sensor that detects the status, detects the output data of this motion sensor when there is no print medium and stores it as reference data, and detects the output data of the motion sensor when there is a print medium Then, by comparing this with the reference data to determine the thickness of the print medium, and in the method of controlling the wire dot print head that performs the auto gap operation to form the head gap according to this medium thickness, it is obtained during the self-adjusting operation. It is determined for each wire whether the sensor output data is within the specified range. If this is the case, the sensor output data obtained by the self-adjustment operation this time is stored as reference data for each wire, and if the sensor output data for a certain number or more of printing wires is abnormal, then for each wire The method for controlling a wire dot print head is characterized in that the previous sensor output data is stored again as the reference data obtained by the self-adjusting operation this time. 4. The operation of the print wire in a wire dot print head for striking a print medium through the ink ribbon at the tip of the print wire by moving the print wire, and transferring the ink to print. Equipped with a motion sensor that detects the status, detects the output data of this motion sensor when there is no print medium and stores it as reference data, and detects the output data of the motion sensor when there is a print medium Then, by comparing this with the reference data to determine the thickness of the print medium, in the method of controlling the wire dot print head that performs an auto gap operation to form a head gap according to the medium thickness, during the auto gap operation, Sensor output data by moving both or one of the print wires located at both ends of the print wires whose tips are arranged in a line Obtained, which determines the thickness of the comparison to the print medium with the reference data, the control method of the wire dot print head and forming a head gap in accordance with the medium thickness.