KR20010098365A - Printing apparatus - Google Patents

Abstract

The present invention provides a printing device that can improve the printing quality by preventing dumping of the printing head. The printing device has a linear motor 2 for reciprocating the print head 1 along each row while the driving current is controlled by a microcomputer, and the inversion zones in the vicinity of both ends in the reciprocating movement section of the print head 1. In addition, it includes the elastic springs 5A and 5B which exert an inversion pressing force with respect to the printing head 1 at the time of moving this inversion zone, and the linear encoder 6 which detects the moving position of the printing head 1; . While moving the reversal zone to the printing head 1, the microcomputer inputs a driving current to the linear motor 2 through the switching circuit so as to generate a force that cancels the reversal pressing force by the elastic springs 5A and 5B. On the other hand, the driving current is controlled based on a pulse signal pattern which is set in advance to change the pulsating and stepwise.

Description

Printing device {PRINTING APPARATUS}

TECHNICAL FIELD The present invention relates to a printing device such as a dot impact method that performs printing for each row while reciprocating the print head, and more particularly, to excellent reciprocating control of the print head.

The dot impact type printing apparatus is a printing head which aligns a plurality of needle pins in a direction orthogonal to the conveying direction of a sheet, integrating one printing row, and taking out the image remarkably. In this type of printing apparatus, printing is effected by selectively stamping the needle pin outwardly from the top of the ink ribbon toward the paper side while reciprocating the printing head along a direction orthogonal to the conveying direction of the paper.

As a mechanism for reciprocating the print head, a linear motor, a linear encoder, or the like is used to move the print head at an almost constant speed in the intermediate zone in the reciprocating section. In addition, in order to reverse the printing head in the vicinity of both ends of the reciprocating movement section, the reverse pressing force by compression and extension of the elastic spring is used. According to such an elastic spring, when the printing head for moving the intermediate zone at constant velocity reaches the inversion zone set near both ends of the reciprocating movement section, the elastic head is gradually decelerated by the inversion pressing force of the elastic spring. As the deceleration proceeds further, if the reverse pressing force of the elastic spring gradually increases, eventually the print head is accelerated by one rotation in the reverse direction. When further entering the intermediate zone from the inversion zone while accelerating, the inversion pressing force is not already applied to the print head, and the print head is moved at the same speed again. The printing head reciprocating repeatedly by this operation is controlled to perform printing when moving at a constant speed, i.e., constant velocity.

By the way, as mentioned above, some printing apparatuses which reciprocate a printing head can switch to several steps, such as a low speed, a normal speed, and a high speed, for example, so that the printing head may respond to various requirements of a user. The moving speed of the print head varies depending on the print mode, but when the print head reciprocates at high speed, a significant reverse pressing force is required for the elastic spring. Therefore, it becomes a non-factor section from the middle of the inversion zone in which the magnitude | size inversion pressing force acts on a printing head, ie, the intermediate zone and a part of the inversion zone which leads to it are fixedly set as a printing section.

Here, considering the case where the print head is moved at a low speed by switching the print mode, since the print section overlaps with the print section at the first entrance or the second retraction in the reversal zone, the reversal pressing force of the elastic spring acts while the print head is operated at constant speed. You must move in or out. Therefore, although the linear motor is controlled by the inversion driving current so as to generate the driving force in the direction of canceling the inversion pressing force, the driving force with respect to the inversion pressing force due to the elastic deformation of the elastic spring simply by applying a normal inversion driving current. There is a problem that dumping occurs in the print head because it cannot be followed.

On the other hand, in the intermediate zone where the reversal pressing force of the elastic spring is not applied, the linear motor is controlled by the constant speed driving current so that the printing head can be moved at constant speed over the entire speed range from low speed to high speed, and then generate a proper driving force. However, at this low speed, since the driving force of the linear motor becomes strong, there is a problem that dumping occurs in the print head even when the print head is controlled to keep the print head at a low speed while maintaining a constant speed.

The above-mentioned problems are not limited to the switchable model of the printing mode, but can be described in general about the printing device for reciprocating the printing head. The occurrence of dumping in the printing head for constant-moving the printing section is caused by deterioration of the printing quality. It was a direct connection.

The present invention has been devised based on the above circumstances, and provides a printing device capable of improving the printing quality by preventing dumping of the printing head so that the printing head reciprocates at a stable constant speed in a section to be printed. It is a task.

In order to solve the said subject, this invention seeks the following technical means.

That is, according to the first aspect of the present invention, a print head for performing a print operation for each row, a reciprocating means for reciprocating the print head along each row by supplying a driving current through a switching means, and the print head A pressurizing means for making inverted zones near both ends in the reciprocating section of the inverted zone and applying an inverted pressing force to the printhead when moving the inverted zone, and detecting the position of the printhead in the reciprocating section. A printing device having means, wherein a driving current is applied to the reciprocating means through the switching means so as to generate a force that cancels the reverse pressing force by the pressing means while the inverting zone moves the inverting zone. On the other hand, in order to change the drive current pulsatingly and stepwise, the detection signal from the detection means The factor apparatus is provided having la driving current control means for controlling said switching means.

According to this printing apparatus, a part of the inversion zone becomes a part of the printing section, and in a part of such an inversion zone, since the inversion pressing force of the pressurizing means acts and moves the printing head at a constant speed, the reciprocating force is canceled. Drive current is input to the moving means. At this time, the driving current changes pulsatingly and stepwise in response to the fluctuating reversal pressing force, so that a force canceling such a reversing pressing force can be generated in a followable manner, and effectively prevents dumping of the print head in the reversing zone. can do. Accordingly, the printing operation can be performed while the printing head is reciprocated at a stable constant speed, thereby improving the printing quality.

According to the second aspect of the present invention, a print head for performing a print operation for each row, a reciprocating means for reciprocating the print head along each row by supplying a driving current through a switching means, and a reciprocating of the print head Pressurization means for making inverted zones near both ends in the movement section, exerting an inverted pressing force on the printhead when moving the inversion zone, and detection means for detecting the position of the printhead in the reciprocating movement section; In a printing device having a driving current, a driving current is supplied to the reciprocating means through the switching means so that the printing head maintains a constant speed while the print head is moving in an intermediate zone in the reciprocating section except for the inversion zone. On the other hand, from the detection means to change the driving current pulsatingly and minutely. There is provided a printing device having drive current control means for controlling the switching means in accordance with a detection signal.

According to such a printing device, since the intermediate zone becomes the printing section and moves the printing head at the same speed in such intermediate zone, a driving current is applied to the reciprocating means so as to obtain a constant speed. At this time, since the drive current is pulsating and changes minutely, the speed generated in the reciprocating means is stable without large fluctuation, and the dumping of the print head in the intermediate zone can be effectively prevented. Accordingly, the printing operation can be performed while the printing head is reciprocated at a stable constant speed, thereby improving the printing quality.

Other features and advantages of the present invention will become more apparent with reference to the accompanying drawings of the embodiments of the present invention.

1 is a schematic diagram showing a schematic structure of one embodiment of a printing device according to the present invention;

Fig. 2 is a block diagram showing the construction of a microcomputer embedded in the printing apparatus according to the present embodiment.

3 is an explanatory diagram for explaining the relationship between the speed and displacement when the print head reciprocates at low speed and the force acting on it;

Fig. 4 is a speed diagram showing the speed change of the print head at high speed and low speed, respectively.

5 is an explanatory diagram for explaining a waveform of a driving current controlled based on a pulse signal pattern.

FIG. 6 is an explanatory diagram for explaining and comparing the velocity jitter waveform of the printing head with the conventional example in this embodiment. FIG.

<Explanation of symbols for the main parts of the drawings>

1: print head

2: linear motor

2A: constant speed coil

2B: Reverse coil

4: fixed shaft

5A, 5B: Elastic Spring

6: linear encoder

10: MPU

1l: ROM

12: RAM

13: interface

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

1 is a schematic diagram showing a schematic structure of an embodiment of a printing apparatus according to the present invention. In addition, this invention has the characteristics in reciprocating movement control of a printing head, Since a basic structure is the same as that of the prior art, illustration is abbreviate | omitted suitably.

As shown in Fig. 1, the printing apparatus reciprocates the printing head 1 which performs the printing operation on a row-by-row basis, the linear motor 2 which generates the driving force in accordance with the interaction between the magnetic field and the current, and the printing head 1 in the reciprocating direction. A pair of fixed shafts 4 which are movably supported along S, which are provided on the fixed shafts 4 and which exert an elastic pressing force (inverting pressing force) when the printing head 1 moves near both ends of the reciprocating movement section. Elastic springs 5A and 5B, and a linear encoder 6 for detecting the position of the printing head 1 in the reciprocating movement section. The printing device has a built-in switching circuit (switching means) for turning on / off the drive current supplied to the linear motor 2 and a microcomputer described later, and various operations are controlled by the microcomputer.

In brief, the printing apparatus according to the present embodiment performs printing on a continuous paper (not shown) according to a dot impact method, and the printing head 1 has a plurality of needle pins (not shown) in the conveying direction F of the continuous paper. It is mounted in the state aligned along the direction orthogonal to. When the print head 1 reciprocates along the direction S orthogonal to the conveying direction F of the continuous sheet, it selectively performs a printing operation in which the needle pin is clearly marked on the ink ribbon (not shown) toward the continuous sheet side. The result is configured to be performed by integrating the arguments for one row.

When reciprocating the print head 1, it is necessary to move it at a constant speed as much as possible in order to improve printing quality, and in order to realize such a reciprocating movement, the linear motor 2 and the linear encoder 6 Etc. are used. Although not shown in FIG. 1, the linear motor 2 has a permanent magnet and an electromagnetic coil as a reciprocating means, and is controlled by a switching circuit to drive a driving current applied to the coil, so that the linear reciprocating movement is necessary for linear reciprocating movement. Generate driving force. As the linear motion of the linear motor 2 is transmitted to the print head 1, the print head 1 moves along the reciprocating direction S. As shown in FIG.

Here, the electromagnetic coil includes a constant speed coil and an inversion coil, and the constant speed coil mainly generates a driving force for moving the print head 1 at a constant speed, and the inverted coil mainly inverts the print head 1. Although the thrust force required at the time is generated, the drive current which makes these coils energized is controlled based on the timing of the detection signal output from the linear encoder 6 based on the pulse signal pattern mentioned later. According to this linear encoder 6, the pulse type movement position detection signal is output in accordance with the movement position of the printing head 1 in the reciprocating movement section, while the printing head 1 is located near both left and right ends in the reciprocating movement section. When the inversion zone described later is reached, an inversion position detection signal is output. That is, the linear encoder 6 is used as detection means for detecting the position of the print head 1 in the reciprocating movement section.

On the other hand, in order to reverse the printing head 1 in accordance with the reciprocating movement, the reverse pressing force due to compression and extension of the elastic springs 5A and 5B is used. These elastic springs 5A and 5B each have a gap between the movable stoppers 4A and 4B provided on the fixed shaft 4 and the ends 1A and 1B facing the reciprocating direction S of the printing head 1. . Although not specifically shown, each movable stopper 4A, 4B with respect to the print head 1 is connected to the linear motor 2 so that it may move to the opposite direction to the moving direction of the print head 1. For example, when the print head 1 is located near the right end of the reciprocating movement section, the left elastic spring 5B is in a compressed state between the end 113 and the movable stopper 4B, and the elasticity The reverse pressing force by the compression of the spring 5B acts on the print head 1 in the left direction. On the contrary, when the printing head 1 is located near the left end of the reciprocating movement section, the right elastic spring 5A is in a compressed state between the end 1A and the movable stopper 4A, and the elastic spring ( The reverse pressing force according to the compression of 5A) acts in the right direction with respect to the printing head 1. The area | region by which the reverse pressing force by such elastic spring 5A, 5B acts is called "inversion zone." On the other hand, when the elastic springs 5A and 5B on both the left and right sides are freely movable between the ends 1A and 1B and the movable stoppers 4A and 4B, inversion by both elastic springs 5A and 5B. The region where the pressing force does not act on the printing head 1 and where the reverse pressing force by such elastic springs 5A and 5B does not act is called "intermediate zone". In short, the elastic springs 5A and 5B are used as pressing means for exerting a reverse pressing force on the printing head 1 when moving the reverse zone.

Here, the reciprocating movement section of the print head 1 is divided into an inversion zone set near both the left and right ends and an intermediate zone therebetween, and the linear motor (1) moves the intermediate zone so that the print head 1 moves at a substantially constant speed. A constant speed drive current is applied to the constant speed coil of 2), and the print head 1 is controlled to perform a printing operation with it. In this embodiment, the operation of the printing head 1 is also controlled in a part of the inversion zone leading to the intermediate zone, but this will be described later.

Fig. 2 is a block diagram showing the configuration of the microcomputer embedded in the printing apparatus according to the present embodiment. As shown in this figure, the microcomputer includes an MPU 10, a ROM 11, a RAM 12, and The interfaces 13 are connected to each other by bus lines. The linear motor 2 and the linear encoder 6 are connected to the interface 13. The MPU 10 controls the reciprocating motion of the print head 1 by controlling the drive current with respect to the linear motor 2 in addition to the print operation by the print head 1. The ROM 11 stores data such as a control program and a set value which the MPU 10 should execute. The RAM 12 is used as a work area or the like of the MPU 10. The interface 13 functions as an input / output contact for the MPU 10. As described above, the linear encoder 6, in addition to the movement position detection signal S1 corresponding to the movement position of the printing head 1, the inversion position detection signal S2 indicating that the printing head 1 reaches the inversion zones on the left and right sides. Outputs S3. The constant speed drive current D1 is input to the constant speed coil 2A of the linear motor 2, while the inverted drive current D2 is input to the inverting coil 2B. A microcomputer having such a configuration will be described later in detail, but to generate a force that cancels the reverse pressing force by the elastic spring (pressing means: 5A, 5B) while the printing head 1 moves the reverse zone. In accordance with the detection signal from the linear encoder (detection means: 6), while injecting a driving current into the linear motor (reciprocating means: 2) via a switching circuit, while changing the driving current pulsatingly and stepwise. Drive current control means for controlling the switching circuit is realized.

3 is explanatory drawing which showed the relationship between the speed and the displacement at the time of the printing head reciprocating at low speed, and the force acting on it, and FIG. 4 is the printing at high speed and low speed, respectively. Speed diagram showing the speed change of the head. In the printing apparatus of this embodiment, the printing mode can be switched to a plurality of stages such as low speed, normal speed, and high speed, and the moving speed of the printing head 1 is also changed in accordance with the printing mode. In particular, as shown in FIG. 4, for example, when the print head 1 reciprocates at high speed, the print head (A) is a reverse zone in which some reverse pressing force is applied by the elastic springs 5A and 5B. 1) is gradually decelerated or accelerated, and the constant speed coil 2A is energized in the middle zone where the reverse pressing force is not applied, so that the printing head 1 is controlled at constant speed. In addition, in this case, since the printing quality does not matter so much, the printing operation is also temporarily performed by the printing head 1 accelerating and decelerating in the inversion zone.

On the other hand, as shown in Figs. 3 and 4, when the printing head 1 is reciprocated at a low speed, the printing quality is improved, so that the inversion zone in which the reverse pressing force of the elastic springs 5A and 5B acts. Even in part of the print head 1 is controlled to move at a constant speed. Specifically, as shown in FIG. 3, when the print head 1 moves the intermediate zone from X1 to X2, the MPU 10 causes the constant speed drive current to the constant speed coil 2A of the linear motor 2. By inputting, the printing head 1 is moved at constant speed only by the driving force of the constant speed coil 2A. At this time, the constant speed drive current supplied to the constant speed coil 2A is pulsated and controlled to change minutely in accordance with the timing at which the movement position detection signal S1 is output from the linear encoder 6, but such constant speed drive current is controlled by the print head. The control is controlled based on the pulse signal pattern for constant speed drive set in advance in the ROM 11 or the like so that 1 is at a constant speed.

When it is detected by the linear encoder 6 that the print head 1 has reached the inversion zone (right) from X2 to X3 and the right inversion position detection signal S3 is outputted, the inversion pressing force of the elastic spring 5B is applied to the print head ( It becomes a state acting on 1). At this time, the MPU 10 not only applies the constant speed drive current to the constant speed coil 2A, but also inverts the drive current to the reverse coil 2B so as to generate a driving force to cancel the reverse pressing force. Put it in. As a result, the reverse pressing force by the elastic springs 5A and 5B and the driving force by the constant speed and the inverting coils 2A and 2B cancel each other, and the printing head 1 continuously moves while maintaining the constant velocity. In addition, at this time, the constant speed drive current injected into the constant speed coil 2A is controlled so as to correspond to the driving force toward a constant direction (right direction), unlike in the case of the intermediate zone from X1 to X2.

Further, even when the print head 1 moves from X3 to X4, as described above, the MPU 10 injects each of the constant speed drive current and the reverse drive current into the constant speed and inversion coils 2A, 2B, thereby causing the print head. While controlling (1) is maintained at the constant velocity, the reverse pressing force increases due to the compressive deformation of the elastic spring 5B gradually. The biggest feature of the present embodiment is that the driving force is generated in the constant speed coil 2A and the inverting coil 2B by following the inverting pressing force thus changed, and therefore the MPU 10 is previously instructed by ROM ( 11) The constant speed drive current and the inverted drive current are controlled based on the pulse signal pattern set in &quot;

Subsequently, considering the case where the print head 1 moves from X4 to X5 at low speed, in this section, only the reverse pressing force of the elastic spring 5B is applied to the print head 1 to advance the print head 1. Since the direction needs to be reversed, the energized state is stopped to drive both the constant speed coil 5A and the inverting coil 5B. That is, only by the reverse pressing force of the elastic spring 5B, the printing head 1 gradually decelerates in the state of constant velocity movement, and eventually reverses the traveling direction at the highest end of X5. In this way, only the reverse pressing force of the elastic spring 5B acts on the print head 1 to sufficiently accelerate the print head 1 while the print head 1 in which the traveling direction is reversed moves from X5 to X6. do.

When the print head 1 moves from X6 to X8 through X7, the elastic spring 5B is elongated and its reverse pressing force gradually decreases. The MPU 10 controls switching to change the drive current pulsatingly and stepwise as described above. As a result, the print head 1 moving from X6 to X8 moves at a substantially constant speed.

FIG. 5 is an explanatory diagram for explaining the waveform of the driving current controlled based on the pulse signal pattern. As shown in this figure, the driving current is sized according to the duty of the pulse signal waveform, and this pulse The signal waveform is a waveform generated by a rising edge of the moving position detection signal S1 output from the linear encoder 6 with a pulse signal pattern composed of a digital value or the like not shown. In other words, the driving current is controlled so as to approximate the ideal current curve based on a preset pulse signal pattern so as to cancel the inverting pressing force of the elastic spring 5B in the inversion zone to make the printing head 1 at a constant speed.

The pulse signal pattern is stored in advance in the ROM 11 or the like as a different pattern for each type of low speed, high speed, etc. in accordance with the switching of the printing mode. In addition, the driving current shown in FIG. 5 is controlled to gradually reduce the driving force and decrease, since the driving force of the printing head 1 is moved at a constant speed while the inverse pressing force decreases, corresponding to the section from X6 to X8 at low speed. In the section from X2 to X4 at low speed, the print head 1 is moved at the same speed when the reverse pressing force increases, so that the driving force is gradually drawn by drawing a waveform in which the current waveform shown in FIG. The drive current is controlled to increase. The waveform of the pulse signal shown in Fig. 5 is generated at the timing of the rising edge of the moving position detection signal S1 output from the linear encoder 6, but may be generated at the timing of the rising edge. It is also possible to generate a pulse signal waveform over a predetermined time length according to the timing at which the signal is periodically output from a timer or the like, using the inversion position detection signals S2 and S3 output from the linear encoder 6 as a trigger.

In addition, with reference to FIG. 3, when it considers after passing of X8, the reversal pressing force by the elastic spring 5B will no longer be able to act on the printing head 1 which passed X8, Next, from X1 to X8 Similarly to the series of operations, the operation of the print head 1 in the section of X1 'to X8' indicated by parentheses in the drawing is controlled. By repeating this operation, the print head 1 reciprocates from the middle zone to the inversion zone. And when the printing head 1 moves a part (X2 to X4, X6 to X8) of the inversion zones subsequent to the intermediate zones X1 to X2, even when the reverse pressing force by the elastic springs 5A and 5B acts. Since the drive currents of the constant speed and inverting coils 2A and 2B are controlled in a variably controlled manner so as to cancel the reverse pressing force, the print head 1 moves at a substantially constant speed so as not to cause dumping, and at that time, the print head 1 The printing quality can be kept good by causing the printing operation to be performed.

FIG. 6 is an explanatory diagram showing the speed jitter waveform of the printing head in the present embodiment in comparison with the conventional example. As can be seen by comparing these figures, the conventional example is formed by the intermediate zone and the inversion zone. The driving current is in an unstable state over the periods X6 'to X4, but according to the present embodiment, the first half entrances X2 to X4 and the second half retreat portions X6' to X1 of the inversion zone from the middle zones X1 to X2. ), A stable driving current can be obtained. This is because the constant speed drive current and the reverse drive current input to the constant speed and inversion coils 2A and 2B are input based on a preset pulse signal pattern. That is, irrespective of whether the moving speed of the printing head 1 is low speed or high speed, the driving head 1 is brought into contact with the constant speed and inversion coils 2A, 2B, ideally based on the pulse signal pattern. It is possible to move at a stable constant speed within the section for printing operation, so that dumping of the printing head 1 can be effectively prevented. In particular, at low speeds, the reverse pressing force of the elastic springs 5A and 5B can be effectively canceled by the propulsion force of the constant speed and the inversion coils 2A and 2B, and the printing head 1 moving from the middle zone to a part of the inversion zone is moved. Can be maintained at a substantially constant speed.

In addition, this invention is not limited to the Example mentioned above.

For example, although the elastic springs 5A and 5B are provided as a pair of right and left, the structure which makes the printing head 1 apply the reverse pressing force with only one elastic spring may be sufficient, and the number, arrangement | positioning, etc. are not limited.

The means for reciprocating the print head 1 is not limited to the linear motor 2 that reciprocates linearly, and the power of the rotary motor may be extracted through a mechanism that converts the rotational motion into a reciprocal linear motion.

In addition, the section for moving the print head 1 at constant speed may include a part of the inversion zone not only at low speed but also at high speed, so long as the print head 1 can perform the print operation at a constant speed. The drive current may be controlled without depending on the pulse signal pattern stored in the circuit).

In addition, although the pulse signal pattern was changed according to the speed change of the printing head 1, the pulse signal pattern was changed in accordance with the elastic springs 5A and 5B due to the change over time, and the propulsion of the coil due to the temperature rise. You can say that.

As described above, according to the present invention, since the driving current changes pulsatingly and stepwise in response to the changing reverse pressing force, it is possible to generate a force compensating for such a reverse pressing force in a reversal zone. Dumping of the print head can be effectively prevented. In addition, in the middle zone, the drive current is pulsated and changes slightly, so that the driving force generated by the linear motor does not fluctuate significantly and is stable, and dumping of the print head in the middle zone can be effectively prevented. Thereby, in the printing section consisting of a part of the intermediate zone and the inversion zone, the printing operation can be performed while reciprocating the printing head at a stable constant speed, and the printing quality can be improved.

While the print head is moving in the inversion zone, the driving current is gradually decreased in accordance with the decrease of the inversion pressing force by the elastic spring, while the acceleration in accordance with the inversion operation is terminated to move at constant speed. In the middle of moving, if the driving current is gradually increased in accordance with the increase of the reverse pressing force by the elastic spring, while moving at the same speed until the deceleration is started by the reversing operation, the followability against the reverse pressing force is offset. Force can be generated in accordance with the drive current, which effectively prevents dumping of the print head.

Further, the drive current is variably controlled in accordance with a timing at which the detection signal is output from the linear encoder or based on a predetermined pulse signal pattern defined according to a timing of a predetermined period, and multiple types of pulse signal patterns are input from the outside. When switching according to the instruction, while changing the drive current on the basis of the pulse signal pattern is set so that the print head is a constant speed in the printing section by the switching, it is possible to optimally control the force generated in the linear motor, Even when the moving speed of the print head becomes low due to the switching of the pulse signal pattern, the print head can be stably moved at a constant speed in the print section including a part of the intermediate zone and the inversion zone.

Claims (2)

A print head for performing a print operation for each row, a driving current supplied through a switching means, and a reciprocating means for reciprocating the print head along each row, and the vicinity of both ends in the reciprocating section of the print head A printing apparatus comprising a pressurizing means for exerting a reverse pressing force on the printing head when moving the inversion zone as a zone, and a detecting means for detecting the position of the printing head in the reciprocating movement section. While driving the inversion zone, the driving current is supplied to the reciprocating means through the switching means while generating the force to cancel the inverse pressing force by the pressing means, while driving the driving current. And drive current control means for controlling said switching means in accordance with a detection signal from said detection means to change dynamically and stepwise. A print head for performing a print operation for each row, a reciprocating means for reciprocating the print head along each row by supplying a driving current through a switching means, and inverted zones in the vicinity of both ends in the reciprocating movement section of the print head. A printing apparatus comprising: pressurizing means for exerting a reverse pressing force on the printing head when moving the inversion zone, and detection means for detecting a position of the printing head in the reciprocating movement section, While the print head is moving the intermediate zone in the reciprocating section except for the inversion zone, a driving current is inputted to the reciprocating means through the switching means so that the print head maintains a constant speed, and the drive is performed. And drive current control means for controlling said switching means in accordance with a detection signal from said detection means so as to change the current pulsatingly and minutely.