JP2003054063A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer wherein a moving speed of a shuttle in a printing region at a time right after the reversing of the shuttle is adequately made to be close to a predetermined speed curve irrespective of change in environment or variation in devices. SOLUTION: This printer comprises a moving speed detecting means that detects the moving speed of the shuttle (S7) in a time period from when the shuttle enters the printing region from a non-printing region by being reversed on at least one end side of the moving path of the shuttle to when a urging force by an urging means does not operate. The printer further comprises a driving force correcting means that allows the speed of the shuttle at the time when the shuttle enters the printing region from the non-printing region to be in conformity with a targeting speed by correcting the driving force of the shuttle driving means based on the speed detected by the moving speed detecting means (S9, S12).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shuttle equipped with a print head, such as an impact printer, and a shuttle drive means for supplying a current to cause the shuttle to travel back and forth along a linear travel path. The present invention relates to a printing apparatus having a biasing unit that is disposed at both ends of a travel route of a shuttle and that applies a biasing force to the shuttle.

[0002]

2. Description of the Related Art In a printing apparatus having a linear motor type shuttle mechanism, a print head mounted on the shuttle, and continuously traveling back and forth, in order to improve the printing speed, the repulsive force of a spring when the shuttle is reversed. A shuttle mechanism using the is being developed.

Such a printing apparatus is, for example, as shown in FIG. 12, a shuttle 51, a linear motor 52, a linear encoder 53, a moving body 54, a belt 55, a pulley 56a,
56b, guide rod 57, and coil springs 58a, 5
8b.

A guide rod 57 is provided at the tip of the moving body 54.
Stoppers 59a and 59b slidably fitted to the print head 51 and the movable body 54 are movable along a guide rod 57. Coil spring 58a,
58b is slidably fitted to the guide rod 57.
The linear motor 52 linearly moves the moving body 54 in the direction of the arrow in FIG. As the moving body 54 moves, the belt 55 connected to the moving body 54 moves, and the belt 5
Along with the movement of 5, the shuttle 5 connected to the belt 55
1 travels in the opposite direction to the moving body 54. Therefore, when the moving body 54 moves to the right in FIG. 12, the shuttle 51 travels to the left, and the coil spring 58b is sandwiched between the shuttle 51 and the stopper 59b of the moving body 54 and compressed. Conversely, when the moving body 54 moves to the left in FIG. 12, the shuttle 51 travels to the right and the coil spring 58a is sandwiched between the print head 51 and the stopper 59a of the moving body 54 and compressed.

Although not shown, the linear motor 52
Includes a plurality of pairs of permanent magnets facing each other at a predetermined interval, and the moving body 5 is provided between the permanent magnets of each pair.
4 coil supports are located. In the coil support,
A plurality of coils are arranged, and each coil is located in the gap between each pair of permanent magnets. Of these coils, two coils at both ends function as constant speed coils, and the remaining coils function as inversion coils. The reversing coil is a coil that mainly applies a propulsive force or a braking force to the shuttle 51 when the shuttle 51 accelerates and decelerates to reverse the traveling direction. The constant speed coil is a coil that mainly applies a propulsive force to the shuttle 51 when the shuttle 51 travels at a constant speed. When reversing the traveling direction of the shuttle 51, the propulsive force applied by the linear motor 52 and the elastic restoring force of the coil spring 58a or the coil spring 58b are used.

Although not shown, the linear encoder 53 includes a slit plate and two photo sensors. The slit plate is attached to the shuttle 51, and as the shuttle 51 travels in a reciprocating straight line, the slit plate moves in a reciprocating straight line with the slit plate facing the photosensor. A large number of slits are formed on the slit plate at a predetermined pitch along the moving direction. The arrangement pitch of the slits is
It is determined by the pixel density of printing. For example, when the pixel density is 180 dpi, the arrangement pitch P is 0.141.
mm.

Although not shown, the pin block installed on the print head mounted on the shuttle 51 has a predetermined interval in a direction inclined with respect to both the traveling direction of the shuttle 51 and the direction orthogonal thereto. In other words, in other words, a plurality of printing pins are installed at a predetermined pitch almost on the diagonal of the pin block. The print head has a shuttle 51
A large number of pin blocks are arranged along the traveling direction of. When the print pin is driven, the print pin presses the print sheet against the platen roller via the ink ribbon, thereby performing printing.

In such a printing apparatus, the shuttle 5
At both ends of the traveling route of No. 1, the shuttle 51 is driven by the total force of the biasing forces of the coil springs 58a and 58b and the driving force of the linear motor 52. For this reason, the current value applied to the coil of the linear motor 52 near both ends of the travel path of the shuttle 51 is set in advance to a value that takes into consideration the biasing force of the coil springs 58a and 58b. That is, in the print area, where the shuttle 51 travels in the direction in which the coil springs 58a and 58b are compressed, the biasing force of the coil springs 58a and 58b acts as a braking force, so that a direction in which the shuttle 51 is given a propulsive force. Energize to prevent speed reduction. Further, in the print area, the shuttle 51 has coil springs 58a, 58.
In the section where b is traveling in the direction of releasing the compression, the biasing force of the coil springs 58a and 58b acts as a propulsion force, so that the shuttle 51 is energized in the direction in which the braking force is applied to prevent overspeed. In the non-printing area, inversion of the shuttle 51 is completed in the shortest possible time. Therefore, the energization direction of the coil is determined so that the shuttle 51 gives a propulsive force in a direction in which the shuttle 51 should advance after the inversion. .

Here, for example, when the printing apparatus is left in a low temperature environment for a long time before the start of printing, the running resistance of the ink ribbon and the flexural rigidity of the belt 55 increase, so that the shuttle 51 is running. Friction load increases. This increase amount is very large compared to a slight fluctuating load generated during the printing operation due to, for example, a step portion or a paper staple portion of the copy paper, and the friction of the bearing or bush of the shuttle 51 moving mechanism increases. Coupled with this, the traveling speed of the shuttle 51 in the printing area immediately after reversing, more specifically, after the shuttle 51 reverses and enters the non-printing area into the printing area, the biasing force of the coil spring 58a or 58b acts on the shuttle 51. The traveling speed of the shuttle 51 in the period until it stops is deviated from the target speed curve, and the speed is exceeded as shown in FIG. It has been experimentally confirmed that, when the frictional load during traveling of the shuttle 51 increases, the shuttle 51 overspeeds as described above. FIG. 14 shows a state where the traveling speed of the shuttle 51 is insufficient.

When the speed of the shuttle 51 is exceeded in this way, the printing capability of the printing pin cannot follow and printing blur occurs and the printing quality deteriorates.

Therefore, in the conventional printing apparatus, the coil spring 5 is provided in the print area so as not to cause print fading.
It has been attempted to prevent overspeeding by increasing the current value of the drive current flowing through the coil 63 so that a propulsive force is generated in the direction opposite to the urging force of 8a or 58b.

[0012]

However, in the above-mentioned conventional printing apparatus, the coil current is controlled immediately after the shuttle 51 enters the printing area immediately after the shuttle 51 is reversed, so that the speed control can be performed satisfactorily. I couldn't. That is, when the approach speed when the shuttle 51 reverses and enters the print area from the non-print area greatly changes due to the ambient temperature of the printing apparatus and the like, even if the coil current is controlled after that, the shuttle 51 causes the coil spring to move. 58a, 58
Shuttle 51 until the urging force of b does not affect
It was very difficult to accurately match the traveling speed of the vehicle with the predetermined speed curve. In addition, due to the influence of the ambient temperature and the like, there are machine differences between individual printing devices, and even if the coil current is uniformly increased, it may not be possible to suppress the speed excess, and the printing speed cannot be stabilized. Furthermore, since the various setting conditions are reset when the printing operation is stopped for a predetermined time or more, the inside of the printing apparatus gradually warms up, and the overspeed prevention control becomes unnecessary. However, since it cannot be determined during continuous operation, the braking force gradually becomes excessive, and the traveling speed of the shuttle 51 in the printing area immediately after reversal gradually decreases, resulting in a decrease in printing speed.

[0013]

DISCLOSURE OF THE INVENTION The present invention has been devised under the circumstances described above, and makes it possible to improve the traveling speed of the shuttle in the printing area immediately after the shuttle is reversed, regardless of changes in environmental conditions and machine differences. It is an object of the present invention to provide a printing device that can approach a predetermined speed curve.

In order to solve the above problems, the present invention takes the following technical means.

According to the first aspect of the present invention, the shuttle having the print head mounted thereon, the shuttle drive means that is supplied with an electric current to reciprocate the shuttle along a linear traveling path, and the traveling path of the shuttle. A printing device having biasing means for applying a biasing force to the shuttle, the shuttle being reversed and entering the printing region from the non-printing region at least at one end side of the traveling path of the shuttle. The traveling speed detecting means for detecting the traveling speed of the shuttle during the period from the time when the urging force by the urging means ceases to act, and the speed detected by the traveling speed detecting means when the shuttle is present in the non-printing area. By correcting the driving force of the shuttle drive means based on the above, the speed when the shuttle enters the printing area from the non-printing area matches the target speed. Characterized in that a driving force correction unit that, the printing apparatus is provided.

According to a preferred embodiment, the shuttle driving means is a linear motor having a magnet and a coil, and the driving force correcting means energizes the coil when the shuttle is present in the non-printing area. The driving force by the shuttle driving means is corrected by changing the timing of shutting off.

According to another preferred embodiment, the shuttle driving means is a linear motor having a magnet and a coil, and the driving force correcting means applies a force to the coil when the shuttle is present in the non-printing area. The driving force by the shuttle driving means is corrected by varying the magnitude of the energizing current of.

According to another preferred embodiment, the shuttle driving means is a linear motor having a magnet and a coil, the coil is supplied with a pulse current of a predetermined cycle, and the driving force correcting means comprises: When the shuttle is present in the non-printing area, the duty ratio of the pulse current supplied to the coil is varied to correct the driving force of the shuttle driving means.

According to another preferred embodiment, the traveling speed detecting means and the driving force correcting means are separately provided for one end portion and the other end portion of the traveling path of the shuttle, respectively. And the other end perform correction control independently of each other.

According to another preferred embodiment, the printing apparatus has a plurality of printing modes having different printing speeds, and the shuttle driving means switches the traveling speed of the shuttle according to the printing mode, and the driving force correcting means. Switches the target speed according to the print mode.

According to another preferred embodiment, the driving force correction means corrects a predetermined correction amount for each inversion of the shuttle according to the speed detected by the traveling speed detection means, and prints. A predetermined correction amount is switched according to the mode.

According to another preferred embodiment, the shuttle drive means is stored in advance in a table format in the storage means while the shuttle is located in the print area and the biasing force of the biasing means is acting. The driving speed of the shuttle is controlled by using the driving data.

According to the present invention, the driving force correcting means corrects the driving force by the shuttle driving means based on the speed detected by the traveling speed detecting means when the shuttle is present in the non-printing area. Since the speed at which the shuttle enters the print area from the non-print area matches the target speed, the shuttle speed in the print area immediately after the shuttle reverses can be satisfactorily maintained at the specified speed regardless of changes in environmental conditions or machine differences. Can approach a curve. Therefore, good printing can be performed without deterioration of the print quality due to the excess speed of the shuttle. Moreover, because the driving force in the non-printing area is corrected based on the previous detection speed each time the shuttle shuttle travels, the braking force will not become excessive due to changes in environmental conditions as the printing progresses, and the printing speed will decrease. Can be effectively prevented.

Other features and advantages of the present invention will become more apparent from the following description of the embodiments of the invention.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a conceptual explanatory view of a printing apparatus according to the present invention. This printing apparatus includes a shuttle 1, a linear motor 2, a linear encoder 3, a moving body 4, a belt 5, pulleys 6a and 6b, a guide rod 7, and coil springs 8a and 8.
b.

Stoppers 9a and 9b slidably fitted to the guide rod 7 are provided at the tip of the movable body 4, and the shuttle 1 and the movable body 4 can move along the guide rod 7. is there. The coil springs 8a and 8b are slidably fitted to the guide rod 7. The linear motor 2 linearly reciprocates the moving body 4 in the arrow direction of FIG. The belt 5 connected to the moving body 4 moves as the moving body 4 moves, and the shuttle 1 connected to the belt 5 travels in the opposite direction to the moving body 4 as the belt 5 moves. Therefore, when the moving body 4 moves to the right in FIG.
The shuttle 1 travels leftward, and the coil spring 8b is sandwiched between the shuttle 1 and the stopper 9b of the moving body 4 and compressed. Conversely, when the moving body 4 moves to the left in FIG. 1, the shuttle 1 travels to the right and the coil spring 8
a is sandwiched between the shuttle 1 and the stopper 9a of the moving body 4 and compressed.

FIG. 2 is a conceptual explanatory view of the linear motor 2. FIG. 3 is a plan view of a main part of the linear motor 2. The linear motor 2 includes a plurality of pairs of permanent magnets 11a and 11b (11 pairs in the present embodiment) that face each other with a predetermined gap.
The coil support portion 12 of the moving body 4 is located between the permanent magnets 11a and 11b of each pair. A plurality of (six in the present embodiment) coils 13 are arranged in the coil support portion 12, and each coil 13 is located in a gap between each pair of permanent magnets 11a and 11b. Of these coils 13, two coils 13 at both ends
Function as constant speed coils, and the remaining four coils function as inversion coils. The reversing coil is a coil that mainly applies a propulsive force or a braking force to the shuttle 1 when the shuttle 1 accelerates and decelerates to reverse the traveling direction, and the constant speed coil causes the print head 1 to travel at a constant speed. This is a coil for mainly applying a propulsive force to the shuttle 1 when performing. When reversing the traveling direction of the shuttle 1, the propulsive force applied by the linear motor 2 and the elastic restoring force of the coil spring 8a or the coil spring 8b are used. That is, when the shuttle 1 enters the non-printing area from the printing area, the linear motor 2 applies a reverse driving force. By applying the propulsive force in the opposite direction in this way, the propulsive force and the elastic restoring force of the coil springs 8a and 8b are combined, and the shuttle 1 is rapidly reversed.

FIG. 4 is a schematic front view of the linear encoder 3. FIG. 5 is a schematic plan view of the linear encoder 3. FIG. 6 is an enlarged front view of the slit plate of the linear encoder 3. The linear encoder 3 has a slit plate 15
And two photo sensors 16. The slit plate 15 is attached to the shuttle 1. As the shuttle 1 travels back and forth in a straight line, the slit plate 15 moves back and forth in a straight line with the slit plate 15 facing the photosensor 16. A large number of slits 17 are formed on the slit plate 15 at a predetermined pitch along the moving direction. The arrangement pitch P of the slits 17 is determined by the pixel density of printing. For example, when the pixel density is 180 dpi, the arrangement pitch P is 0.141 mm.

FIG. 7 is an explanatory diagram of the pin block installed in the print head mounted on the shuttle 1. The pin block 21 is provided with a predetermined interval in a direction inclined with respect to both the traveling direction of the shuttle 1 shown by the arrow A in FIG. 7 and the direction orthogonal thereto, in other words, substantially on the diagonal line of the pin block 21. A plurality of (13 in the present embodiment) print pins 22 are installed at a predetermined pitch. The print head has a pin block 21 along the traveling direction of the shuttle 1.
Are arranged in large numbers. For example, printing paper (not shown) made of continuous paper is conveyed in the direction of arrow B in FIG. 7. Although not shown, printing is performed by driving the printing pin 22 to press the printing paper against the platen roller via the ink ribbon.

That is, the mechanism portion of the printing apparatus in this embodiment has the same structure as the conventional printing apparatus shown in FIG.

FIG. 8 is a schematic circuit block diagram of the control unit of the printing apparatus according to the present invention. This control unit is
5, ROM 26, RAM 27, and interface circuit 28. These MPU25, ROM2
6, the RAM 27, and the interface circuit 28,
They are connected to each other by bus lines. The coil 13 of the linear motor 2 and the photosensor 16 of the linear encoder 3 are connected to the interface circuit 28.

An MPU (microprocessor unit) 25 controls the entire printing apparatus.

ROM (read only memory) 26 is an MP
It stores data such as control programs and set values to be executed by U25.

A RAM (random access memory) 27 is
It is used as a work area of the MPU 25 and stores various data.

The interface circuit 28 is the MPU 25.
It controls the exchange of signals between the linear motor 2 and the linear encoder 3.

FIG. 9 is an explanatory diagram of a traveling state of the shuttle 1 from one end to the other end of the travel route. 9 and 10, the coil springs 8a and 8b are fixed to facilitate understanding, and when the shuttle 1 travels to the left, the coil spring 8a is compressed and when the shuttle 1 travels to the right. It is assumed that the coil spring 8b is compressed. At the moment when the shuttle 1 is reversed on the left end side in FIG. 9, that is, when the traveling speed of the shuttle 1 is 0, the coil spring 8a is in the most compressed state. Further, the coil 13 of the linear motor 2 is already energized in a direction in which a driving force for causing the shuttle 1 to travel to the right is applied. Therefore, in the left non-printing area, the shuttle 1
The driving force in the right direction is given by both the driving force from the linear motor 2 and the elastic restoring force of the coil spring 8a.

The shuttle 1 is reversed by the driving force described above, starts traveling to the right, and immediately before entering the printing area from the non-printing area, the power supply to the coil 13 of the linear motor 2 is cut off. The timing of this power interruption is controlled by the MPU 25. In the present embodiment, as will be described later in detail, by controlling this timing, the entry speed of the shuttle 1 from the non-printing area to the printing area is adjusted.

When the shuttle 1 enters the print area from the non-print area, the MPU 25 reads the drive data stored in the ROM 26 in a table format, and a stepwise drive current corresponding to the read drive data is applied to the coil 13 of the linear motor 2. It is energized. At this time, the linear motor 2 is operated by the shuttle 1
Is generated to the left side of FIG. That is, at this position, a large force for moving the shuttle 1 to the right side in FIG. 9 is exerted by the coil spring 8a, so that it is suppressed and the traveling speed of the shuttle 1 is maintained at a predetermined speed. In addition, the current supplied to the coil 13 decreases stepwise. This is because the elastic restoring force of the coil spring 8a becomes smaller as the shuttle 1 moves to the right side in FIG. 9, so that the braking force by the linear motor 2 becomes smaller accordingly. Of course, the MPU 25 drives the print pin 72 based on the print data, and printing is performed as the shuttle 1 travels. Furthermore, the MPU25
The traveling speed of the shuttle 1 is measured based on the signal from the linear encoder 3 and stored in the RAM 27.

When the shuttle 1 travels to a position where the urging force of the coil spring 8a does not act, the MPU 25 energizes the coil 13 of the linear motor 2 with a predetermined current to drive the shuttle 1 at a predetermined speed. At this time, the linear motor 2 generates a propulsive force that moves the shuttle 1 to the right side in FIG. Further, the printing apparatus according to the present embodiment can selectively use a plurality of types of printing modes having different printing speeds, and the shuttle 1 is controlled by the MPU 25 and travels at a speed according to the printing mode.

When the shuttle 1 approaches the right end of the print area and reaches the position where the biasing force of the coil spring 8b acts, M
The drive data stored in the ROM 26 in a table format is read by the PU 25, and a stepwise drive current corresponding thereto is applied to the coil 13 of the linear motor 2.
At this time, the linear motor 2 generates a propulsive force that moves the shuttle 1 to the right side in FIG. That is, at this position, the coil spring 8b exerts a force that prevents the shuttle 1 from traveling, so that it is suppressed and the traveling speed of the shuttle 1 is maintained at a predetermined speed. The current supplied to the coil 13 increases stepwise. This is the shuttle 1
This is because the elastic restoring force of the coil spring 8b increases as it moves to the right side of, and the propulsive force by the linear motor 2 also increases accordingly.

When the shuttle 1 enters the non-printing area from the printing area, the MPU 25 controls the linear motor 2 so that the coil 13 is supplied with a reverse current. That is, in order to make the reversal time of the shuttle 1 as short as possible, a driving force for moving the shuttle 1 to the left side in FIG. 9 is applied by the linear motor 2. Due to this driving force and the elastic restoring force of the coil spring 8b, the shuttle 1 is quickly inverted and starts traveling to the left side in FIG.

The above operation is repeated, and the shuttle 1 repeats the reciprocating movement along the guide rod 7 to print.

FIG. 10 is a schematic explanatory view of the relationship between the traveling state of the shuttle 1 and the energization state of the coil 13 of the linear motor 2.

If printing is started and the shuttle 1 is first inverted at the left end side of the travel route of the shuttle 1,
After the shuttle 1 is reversed, during the period L1 until the shuttle 1 enters the print area from the non-print area and is not affected by the biasing force of the coil spring 8a, the MPU 25 causes the shuttle 1 to move based on the signal from the linear encoder 3. The traveling speed is measured and stored in the RAM 27.

The shuttle 1 travels to the right side of FIG. 10, and after the shuttle 1 reverses at the right end side of the travel route, the shuttle 1 enters the printing area from the non-printing area until it is no longer subjected to the biasing force of the coil spring 8b. During period R1 of
The traveling speed of the shuttle 1 is measured by the PU 25 based on the signal from the linear encoder 3 and stored in the RAM 27.

When the shuttle 1 travels to the left side of FIG. 10 and the shuttle 1 enters the non-printing area from the printing area on the left end side of the travel path of the shuttle 1, the reversing current A is supplied to the coil 13 of the linear motor 2 by the MPU 25. It At this time, the MPU 25 measures during the period L1 and measures the RAM.
Based on the traveling speed of the shuttle 1 stored in 27, the interruption timing of the reversal current A is controlled. That is, when the traveling speed of the shuttle 1 in the period L1 exceeds the predetermined speed, the shut-off timing of the reversal current A is advanced to reduce the entry speed of the shuttle 1 from the non-printing area to the printing area. On the contrary, when the traveling speed of the shuttle 1 in the period L1 does not reach the predetermined speed, the shut-off timing of the reversal current A is delayed to increase the approach speed of the shuttle 1 from the non-printing area to the printing area.

As a result, after the shuttle 1 is reversed, the shuttle 1 enters the printing area from the non-printing area, and the coil spring 8
During the period L2 until the urging force of a is no longer applied, the traveling speed of the shuttle 1 is brought close to a predetermined speed by the stepwise drive current C to the coil 13 of the linear motor 2 controlled by the MPU 25. That is, although the drive current C is the same in the period L1 and the period L2, the approach speed of the shuttle 1 from the non-printing area to the printing area is controlled to be the target speed, so that the shuttle 1 travels in the period L2. The speed approaches the predetermined speed.

Then, also in the period L2, the MPU 25
Thus, the traveling speed of the shuttle 1 is measured based on the signal from the linear encoder 3 and stored in the RAM 27.

When the shuttle 1 travels to the right side of FIG. 10 and the shuttle 1 enters the non-printing area from the printing area on the right end side of the traveling path of the shuttle 1, the reversing current B is supplied to the coil 13 of the linear motor 2 by the MPU 25. It At this time, the MPU 25 measures and RAMs during the period R1.
Based on the traveling speed of the shuttle 1 stored in 27, the interruption timing of the reversal current B is controlled. That is, when the traveling speed of the shuttle 1 in the period R1 exceeds the predetermined speed, the shut-off timing of the reversal current B is advanced to reduce the entry speed of the shuttle 1 from the non-printing area to the printing area. On the contrary, when the traveling speed of the shuttle 1 in the period R1 has not reached the predetermined speed, the shut-off timing of the reverse current B is delayed to increase the approach speed of the shuttle 1 from the non-print area to the print area.

As a result, after the shuttle 1 is reversed, the shuttle 1 enters the printing area from the non-printing area, and the coil spring 8
During the period R2 until the urging force of b is not exerted, the traveling speed of the shuttle 1 is brought close to a predetermined speed by the stepwise drive current D to the coil 13 of the linear motor 2 controlled by the MPU 25. That is, the driving current D is the same in the period R1 and the period R2, but the approach speed of the shuttle 1 from the non-printing area to the printing area is controlled to be the target speed, so that the shuttle 1 travels in the period R2. The speed approaches the predetermined speed.

Then, also in the period R2, the MPU 25
Thus, the traveling speed of the shuttle 1 is measured based on the signal from the linear encoder 3 and stored in the RAM 27.

Similarly, the cutoff timing of the reversing currents A and B at each time is controlled based on the traveling speed of the shuttle 1 immediately after the previous reversing, and the entry speed of the shuttle 1 from the non-printing area to the printing area is adjusted. To be done. For example, the cutoff timing of the reversal current A immediately before the period L3 is controlled based on the traveling speed of the shuttle 1 measured in the period L2, and the traveling speed of the shuttle 1 in the period R3 is controlled based on the traveling speed of the shuttle 1 measured in the period R2. The cutoff timing of the reversal current B immediately before is controlled.

FIG. 11 is a flow chart for explaining the procedure of the reverse current cutoff timing control process by the MPU 25.

When printing is started, the MPU 25 first
Predetermined default values are set in the reversal timer that determines the energization time tL of the reversal current A and the reversal timer that determines the energization time tR of the reversal current B (S1).

Next, the MPU 25 determines whether or not the shuttle 1 has traveled to the reverse position (S2). That is, M
Based on the signal from the linear encoder 3, the PU 25 checks whether the shuttle 1 has entered the non-printing area from the printing area on the left end side or the right end side of the travel route.

If the shuttle 1 is traveling to the reverse position (S2: YES), the MPU 25 starts energizing the reverse current A or B (S3). That is, in the case of the left end reversal position, the energization of the reversal current A is started, and in the case of the right end reversal position, the energization of the reversal current B is started.

Then, the MPU 25 starts the inversion timer (S4). That is, the inversion timer that determines the energization time tL of the inversion current A is started at the left end inversion position, and the inversion timer that determines the energization time tR of the inversion current B is started at the right end inversion position.

Next, the MPU 25 determines whether or not the inversion timer has timed out (S5). That is, at the left end reversal position, it is checked whether or not the reversal timer that determines the conduction time tL of the reversal current A has timed up,
At the reverse position on the right end side, the conduction time t of the reverse current B is
Check if the reversal timer that determines R has timed out.

If the inversion timer has timed out (S
5: YES), the MPU 25 cuts off the reverse current (S6). That is, the reverse current A is cut off at the left end reversal position, and the reversal current B is cut off at the right end reversal position. It should be noted that the default value is set in the reversal timer at the first inversion on the left end side and the right end side after the start of printing, so the energization time of the reversal current becomes the default energization time. The default energization time is determined in advance according to various print modes.

Next, the MPU 25 measures the traveling speed of the shuttle 1 based on the signal from the linear encoder 3 (S7). That is, immediately after the shuttle 1 is reversed,
The MPU 25 calculates the traveling speed of the shuttle 1 based on the signal from the linear encoder 3 during the period from when the shuttle 1 enters the printing area from the non-printing area until it is no longer acted upon by the biasing force of the coil spring 8a or 8b. Then, it is stored in the RAM 27.

Next, the MPU 25 determines whether or not the traveling speed of the shuttle 1 has exceeded (S8). That is, it is checked whether or not the traveling speed of the shuttle 1 calculated in step S7 exceeds a predetermined speed by a certain value or more. The predetermined speed is predetermined according to various print modes.

If the traveling speed of the shuttle 1 has exceeded (S8: YES), the MPU 25 decreases the set value of the reversal timer by, for example, 200 μsec (S9). That is, by reducing the energizing time of the reversing current and decreasing the entry speed from the non-printing area to the printing area, it is possible to prevent the traveling speed of the shuttle 1 from exceeding the traveling speed in the printing area immediately after the next reversal at the same position. Of.

Next, the MPU 25 determines whether or not the printing is completed (S10). That is, it is checked whether traveling of the shuttle 1 is unnecessary.

If printing is completed (S10: YE
S), the reverse current cutoff timing control process ends.

If the printing is not completed in step S10 (S10: NO), the process returns to step S2 to continue the reverse current interruption timing control.

In step S8, if the traveling speed of shuttle 1 does not exceed (S8: NO), MPU25
However, it is determined whether or not the traveling speed of the shuttle 1 is insufficient (S11). That is, it is checked whether the traveling speed of the shuttle 1 calculated in step S7 is lower than a predetermined speed by a certain value or more.

If the traveling speed of shuttle 1 is insufficient (S11: YES), MPU 25 increases the set value of the reversal timer by, for example, 200 μsec (S12), and proceeds to step S10. That is, by increasing the energizing time of the reversing current to increase the entry speed from the non-printing area to the printing area, the shortage of the traveling speed of the shuttle 1 in the printing area immediately after the next reversal at the same position is solved. Of.

If the traveling speed of the shuttle 1 is not insufficient in step S11 (S11: NO), the process proceeds to step S10. That is, since there is no excess or deficiency in the traveling speed of the shuttle 1, the set value of the reversal timer is not changed.

If the inversion timer has not timed out in step S5 (S5: NO), step S5
Return to and wait for the inversion timer to time out.

In step S2, if shuttle 1 has not traveled to the reverse position (S2: NO), the process returns to step S2 and waits for shuttle 1 to reach the reverse position.

Thus, according to the traveling speed of the shuttle 1 in the periods L1, L2, L3, or the periods R1, R2, R3, the next period L2, L3, or the period R2, R3 ,. Since the energization time of the immediately preceding reversal current is controlled, the entry speed of the shuttle 1 from the non-printing area to the printing area can be controlled well, and therefore the next period L2, L
3, -or shuttle 1 in period R2, R3,-
It is possible to make the traveling speed of the vehicle close to a predetermined speed.

Therefore, when the frictional load during traveling of the shuttle 1 increases due to environmental conditions or the like, the traveling speed of the shuttle 1 exceeds the target speed due to the urging force of the coil springs 8a or 8b in the printing area immediately after reversal. do it,
There is no possibility that the printing performance of the printing pin 72 cannot be followed and a printing defect such as a print blur occurs.

Particularly, in the print area immediately after the reversal, the RO
Based on the drive data stored in the table format in M26, the stepwise drive current C or D is applied to the linear motor 2
In the case of performing precise and complicated control of supplying the coil 13 to the coil 13, the inversion speed of the shuttle 1 from the non-printing area to the printing area can be made equal to the target value by controlling the reversing current. According to precise and complicated control, the traveling speed of the shuttle 1 in the printing area immediately after the reversal can be properly adjusted.

In addition, since the energizing time of the reversing current A or B is changed according to the traveling speed of the shuttle 1 immediately after the previous reversing at the same position every time the shuttle 1 is reversing each time, regardless of the change of the environmental conditions. The traveling speed in the print area immediately after the shuttle 1 is reversed can be always maintained at a predetermined speed,
Printing speed is not reduced. That is, as in the conventional printing apparatus, when the ambient temperature changes with the progress of printing and the frictional resistance during traveling of the shuttle 1 decreases,
The control that suppresses the traveling speed in the printing area immediately after the shuttle 1 is reversed is continued until the end of printing, and the printing speed does not decrease due to an excessive braking force.

Further, regardless of variations in characteristics of the coil springs 8a and 8b among individual products and changes in propulsive force of the linear motor 2 due to changes in ambient temperature, non-printing immediately after the shuttle 1 is reversed. Since the entry speed from the area to the print area can always be controlled well, the print quality can be stabilized.

If the reverse current A or B is controlled independently on the left end side and the right end side of the travel route of the shuttle 1 as in this embodiment, the characteristic difference between the coil spring 8a and the coil spring 8b is obtained. Optimal control can always be performed regardless of the above.

In the above embodiment, the interruption timing of the reversal current A or B is made variable, but instead of this, the current value of the reversal current A or B may be made variable. Alternatively, the reversal current A or B may be a pulse current having a predetermined cycle, and the duty ratio thereof may be varied.

Further, in the above-described embodiment, the left end side and the right end side of the traveling route of the shuttle 1 are controlled independently of each other, but the shuttle is operated on either the left end side or the right end side of the traveling route. It is also possible to measure the traveling speed of No. 1 and control the reversal currents on the left end side and the right end side based on the measurement result.

Although the linear motor 2 is used as the shuttle driving means in the above embodiment, a DC motor or the like may be used instead of the linear motor 2.

Further, in the above-described embodiment, an example in which a plurality of kinds of print modes having different traveling speeds of the shuttle 1 are provided has been described, but the print mode may be one kind.

In the above embodiment, the ROM 2
Although the drive current C or D was changed stepwise according to the drive data stored in 6, the speed control method in the printing area immediately after reversal is arbitrary.

Further, in the above embodiment, the reversing timer is configured to increase / decrease by a predetermined time for each reversing, but there is no step or every reversing depending on the measurement result of the traveling speed of the shuttle 1. The setting time of the inversion timer may be changed in a plurality of steps.

Further, in the above embodiment, when the traveling speed of the shuttle 1 does not exceed the predetermined speed by a fixed value or more, and is not less than the predetermined speed by a fixed value or more, the set value of the reversal timer is changed. Although not configured to be changed, if the traveling speed of the shuttle 1 is higher than a predetermined speed, the set value of the reversal timer is decreased by a constant value, and if it is slower than the predetermined speed, the set value of the reverse timer is increased by a constant value. You may comprise.

[0085]

As described above, according to the present invention, the driving force correcting means drives the shuttle driving means based on the speed detected by the traveling speed detecting means when the shuttle is present in the non-printing area. By correcting the force, the speed at which the shuttle enters the printing area from the non-printing area matches the target speed, so the shuttle travels in the printing area immediately after the shuttle reverses, regardless of changes in environmental conditions or machine differences. It is possible to satisfactorily bring the speed close to the predetermined speed curve. Therefore, good printing can be performed without deterioration of the print quality due to the excess speed of the shuttle. Moreover, because the driving force in the non-printing area is corrected based on the previous detection speed each time the shuttle shuttle travels, the braking force will not become excessive due to changes in environmental conditions as the printing progresses, and the printing speed will decrease. Can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a conceptual explanatory diagram of a printing apparatus according to the present invention.

FIG. 2 is a conceptual explanatory diagram of a linear motor.

FIG. 3 is a plan view of a main part of a linear motor.

FIG. 4 is a schematic front view of a linear encoder.

FIG. 5 is a schematic plan view of a linear encoder.

FIG. 6 is an enlarged front view of a slit plate of the linear encoder.

FIG. 7 is an explanatory diagram of a pin block installed in a print head mounted on the shuttle.

FIG. 8 is a schematic circuit block diagram of a control unit of the printing apparatus according to the present invention.

FIG. 9 is an explanatory diagram of a traveling state from one end to the other end of the travel route of the shuttle.

FIG. 10 is a schematic explanatory view of the relationship between the traveling state of the shuttle and the energization state of the coil of the linear motor.

FIG. 11 is a flowchart illustrating a procedure of reverse current cutoff timing control processing by the MPU.

FIG. 12 is a conceptual explanatory diagram of a conventional printing apparatus.

FIG. 13 is an explanatory diagram of the relationship between the traveling position of the shuttle and the traveling speed, in the case of overspeed.

FIG. 14 is an explanatory diagram of the relationship between the traveling position of the shuttle and the traveling speed when the speed is insufficient.

[Explanation of symbols]

1 shuttle 2 linear motor 3 linear encoder 4 moving bodies 5 belt 6a, 6b pulley 7 Guide rod 8a, 8b coil spring 9a, 9b stopper 11a, 11b Permanent magnet 12 Coil support 13 coils 15 slit plate 16 Photo sensor 17 slits 21 pin block 22 Print pin 25 MPU 26 ROM 27 RAM 28 Interface circuit

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C480 CA01 CA11 CA33 CA57 CB04                       EA01 EA14 EA27

Claims (8)

[Claims] 1. A shuttle equipped with a print head, shuttle driving means that is supplied with an electric current to reciprocate the shuttle along a linear traveling path, and is arranged at both ends of the traveling path of the shuttle. ,
A printing apparatus having a biasing means for applying a biasing force to the shuttle, wherein the bias is applied from the time when the shuttle reverses and enters the printing area from the non-printing area on at least one end side of the traveling path of the shuttle. A traveling speed detecting means for detecting a traveling speed of the shuttle during a period until the urging force by the urging means stops acting, and a detecting speed by the traveling speed detecting means when the shuttle is present in a non-printing area And a driving force correcting unit for correcting the driving force of the shuttle driving unit based on the shuttle driving unit based on the shuttle driving unit so that the speed when the shuttle enters the printing region from the non-printing region matches the target velocity. Printing device. 2. The shuttle driving means is a linear motor having a magnet and a coil, and the driving force correcting means cuts off energization to the coil when the shuttle is present in a non-printing area. The printing apparatus according to claim 1, wherein the driving force of the shuttle driving unit is corrected by changing the timing of the operation. 3. The shuttle driving means is a linear motor having a magnet and a coil, and the driving force correcting means controls a current supplied to the coil when the shuttle is present in a non-printing area. The printing apparatus according to claim 1, wherein the driving force by the shuttle driving unit is corrected by changing the size. 4. The shuttle drive means is a linear motor having a magnet and a coil, a pulse current of a predetermined cycle is supplied to the coil, and the driving force correction means does not print the shuttle. The printing apparatus according to claim 1, wherein the driving force of the shuttle driving unit is corrected by varying the duty ratio of the pulse current supplied to the coil when the printer is in the area. 5. The traveling speed detecting means and the driving force correcting means are provided separately for one end and the other end of the traveling path of the shuttle, and one end and the other end are provided. The printing apparatus according to any one of claims 1 to 4, wherein the correction control is performed independently of each other. 6. A plurality of print modes having different print speeds are provided, the shuttle drive means switches the traveling speed of the shuttle according to the print mode, and the drive force correction means causes the print speed to be changed. The printing apparatus according to claim 1, wherein the target speed is switched according to a mode. 7. The driving force correction means corrects a predetermined correction amount for each inversion of the shuttle according to the speed detected by the traveling speed detection means, and according to the print mode. 7. The predetermined correction amount is changed over.
The printing device according to. 8. The shuttle drive means uses drive data stored in advance in a table format in the storage means while the shuttle is in the print area and the biasing force of the biasing means is acting. The printing apparatus according to claim 1, wherein the traveling speed of the shuttle is controlled.