JPH10129069A - Carriage driving mechanism for serial head type recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carriage driving mechanism for a serial head type recorder for preventing change of a head position of printing in each row. SOLUTION: This carriage driving mechanism comprises a belt 50 for moving a carriage 5 having serial heads mounted to print a recording sheet, a drive pulley 51 and tension pulley 52 between which the belt 50 is bridged over, a driving means for giving a driving force to the pulley 51, a holder 53 for rotatably holding the pulley 52 and movably provided in a predetermined range in a belt bridging direction, and a spring 55 for giving tension to the belt 50. In this case, a stopper member 57 is provide corresponding to a position of the holder 53 when the carriage 5 is steadily stopped, and the holder 53 may not be moved in a direction for shortening a distance between the pulleys 51 and 52 from the previous position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a carriage driving mechanism for a serial head type recording apparatus that performs printing using a serial head.

[0002]

2. Description of the Related Art FIG. 1 is a perspective view showing a main part of a general serial head type recording apparatus. The serial head type recording apparatus includes a transport roller 1a for transporting a recording paper 10 (not shown in this figure; see FIG. 2) and a transport roller 1a provided to face the transport roller 1a.
, A paper transport roller unit 1 composed of a pinch roller 1 b for pinching the recording paper, a platen 2 disposed near the paper transport roller unit 1, and the leading end of the recording paper to the paper transport roller unit 1.
Feed roller 8 which feeds the feed roller, a conveying pulse motor (not shown) which rotates by a predetermined angle in response to a pulse, and a gear for transmitting the rotational force of the conveying pulse motor to the conveying roller 1a and the feeding roller 8. A group 3, a thermal type serial head 4 for printing on a recording paper 10,
A carriage 5 to which a head support 15 (not shown in FIG. 2; see FIG. 2) for supporting the serial head 4 is attached, an ink ribbon cassette 6 set on the carriage 5, and recording on the carriage 5. A shaft 7 that guides the paper in the lateral direction and a paper feed plate 12 on which recording paper is placed are provided.

FIG. 2 is an explanatory view showing a general printing mechanism. The recording paper 10 is located between the serial head 4 and the platen 2. The ink ribbon 6a of the ink ribbon cassette 6 is interposed between the recording paper 10 and the serial head 4. The serial head 4 and the ink ribbon cassette 6 move in the left direction (carriage scanning direction) in FIG. 2, and the ink ribbon 6a is fed out from the paper feed side roll 6b and wound up by the wind side roll 6c. Then, when one line is printed, the transport roller 1a is driven, and the recording paper 10 is moved by the line feed width (that is, line feed is performed).

FIG. 5 is a schematic view showing a conventional carriage driving mechanism. The carriage 5 is fixed to a belt 50, and is guided and moved by the shaft (not shown in FIG. 5) 7 by the movement of the belt 50. The belt 50 is stretched around a driving pulley 51 and a tension pulley 52. The drive-side pulley 51 is adapted to obtain the driving force of a drive pulse motor (not shown) via a gear system (not shown) and rotate to move the belt 50.

FIG. 6 is a plan view showing components on the tension pulley 52 side in a conventional carriage driving mechanism. The tension pulley 52 is rotatably supported by a tension pulley shaft 53a of a holder 53, and the holder 53 can be moved in a notch portion (not shown) formed in the chassis 54 in a belt passing direction within a predetermined range. It has become. A spring 55 is contracted between the bent portion 54a of the chassis 54 and the holder 53, and the holder 53 is urged in a direction to pull the belt 50.

In the above-mentioned carriage driving mechanism, the home position of the carriage 5 is set, and the carriage 5 is detected by a sensor (not shown) provided at a position corresponding to the home position. Home position positioning can be performed. At the time of printing, the operation of moving the carriage 5 to the left end of the recording paper and positioning the serial head 4 at the printing start position of each row is performed by a predetermined number of pulses set in advance in the drive pulse motor. Is going to give.

[0007]

However, the above-described conventional carriage driving mechanism has a drawback in that a shift occurs in the printing start position of each row (line start shift). FIG.
Is a schematic diagram showing a state in which three lines and approximately one third of the next line are printed on the recording paper 10, but as shown in FIG. Has occurred. When such variations occur, the images become discontinuous at the boundaries of each row, and the image quality deteriorates. On the other hand, it can be seen from FIG. 7 that the end positions of each row are aligned. This means that the position of the carriage 5 is not determined at the start of printing, but is gradually determined as the carriage 5 scans. The cause of the line misalignment and the printing end position are considered, and will be described below.

The load applied to the carriage 5 differs between printing and returning. At the time of printing, the serial head 4 moves while pressing the ink ribbon 6a and the recording paper 10 while pressing, so that the carriage 5 including the serial head 4 and the ink ribbon 6a therein receives a frictional load from the external recording paper 10. At the time of return, such frictional load is not received. Further, at the time of printing, the carriage 5 is strongly contacted with the shaft 7 by the above-mentioned press contact, so that a load due to a large sliding friction is received between the carriage 5 and the shaft. , The carriage 5 comes into light contact with the shaft 7 and receives only a load due to a small sliding friction therebetween. Then, the belt tension in the moving direction and the belt tension in the opposite direction act on the carriage 5. When the carriage 5 moves at a constant speed, the external force should be balanced, so that the difference between these opposite belt tensions and the load on the carriage 5 are balanced.

Further, a moment due to the belt tension in the moving and rotating direction of the carriage 5 and a moment due to the belt tension in the rotating direction opposite to the moving direction act on the driving pulley 51. Further, friction torque is generated in a direction that hinders movement. Drive side pulley 5
Since the moment due to the external force should be balanced at the time of the constant angular velocity motion of 1, the driving torque transmitted from the driving source is balanced with the difference between the moment due to the opposite belt tension and the sum of the friction torque.

The tension pulley 52 is also acted on by the moment of the belt tension in the direction of rotation of the carriage 5 and the moment of the belt tension in the direction of rotation opposite to the direction of movement. Also,
Friction torque is generated in the direction that hinders movement. During the constant angular velocity movement of the tension pulley 52, the moment due to the external force should be balanced, so that the difference in moment due to the opposite belt tension and the friction torque are balanced. Further, the tension pulley 52 is
Does not move in the belt passing direction at the time of constant speed movement of the belt 55, the spring 55 is pulled in the direction of pulling the belt 50.
And the sum of the two belt tensions acting in opposite directions are balanced.

In such a state where the forces are balanced, when the load from the carriage 5 fluctuates, the driving force, the tension, and the force of the spring 55 acting on the tension pulley shaft 53a fluctuate. The holder 53 stops at various positions depending on the magnitude of the frictional force between the holder 53 and a not-shown notch formed in the chassis 54. Further, the frictional force between the shaft 7 and the shaft receiving portion of the carriage 5 is not always constant. For example, a shaft receiving portion made of resin has a larger coefficient of thermal expansion than that of the metal that is the material of the shaft 7. The size of the gap between the shaft and the bearing changes depending on the temperature, and the frictional force also changes. Further, the frictional force received from the recording paper 10 also varies depending on the printing density. If the density is high, the force with which the ink ribbon 6a adheres to the recording paper 10 increases, and as a result, the frictional force increases. Thus, since each force fluctuates, the position of the holder 53 (the position of the tension pulley 52) determined by the result of the force balance also fluctuates.

That is, when the driving pulley 51 is rotated in order to move the carriage 5 in the scanning direction, the carriage 5 starts being accelerated by being pulled by the belt 50. Then
The holder 53 moves in a direction to reduce the distance between the pulleys 51 and 52 due to the tension generated on the belt 50.
When the carriage 5 moves at a constant speed, the belt 50 moves.
Of the pulley 51, the holder 53
It will move somewhat in the direction to extend the distance between the two,
The amount of movement of the holder 53 is not fixed due to friction between the holder 53 and the notch, and the position of the holder 53 fluctuates. Then, the position of the carriage 5 fixed to one point of the belt 50 (that is, the position of the serial head 4) also changes. When printing is started after the start of the constant velocity movement, the carriage 5
, The head of each line shifts.

On the other hand, the printing end positions are aligned because during the running of the carriage 5 at the time of printing, each friction is reduced by the constant velocity movement of the carriage 5 and the constant angular velocity movement of each of the pulleys 51 and 52. It is considered that the force converges to a certain size and the respective forces are balanced, so that the position of the holder 53 converges to a fixed position at the end of printing of each row.

In view of the above circumstances, it is an object of the present invention to provide a carriage driving mechanism of a serial head type recording apparatus capable of preventing a change in a leading position of printing in each line.

[0015]

SUMMARY OF THE INVENTION A carriage driving mechanism of a serial head type recording apparatus according to the present invention includes a belt for moving a carriage on which a serial head for performing printing on recording paper is attached, and a belt extending over the belt. A driving pulley and a tension pulley, a driving means for applying a driving force to the driving pulley, a holder rotatably holding the tension pulley, and being movable in a predetermined range in a belt passing direction, and the holder A biasing means for biasing the belt to apply tension to the belt, wherein a stopper member is provided corresponding to the position of the holder when the carriage is stationary. And the holder cannot move in a direction to reduce the distance between the pulleys from the position. Characterized in that it is configured to.

A carriage driving mechanism of a serial head type recording apparatus according to the present invention includes a belt for moving a carriage on which a serial head for printing on recording paper is mounted, and a driving pulley around which the belt is stretched. And a tension pulley; a driving means for applying a driving force to the driving pulley; a holder provided rotatably for holding the tension pulley and being movable within a predetermined range in a belt passing direction; and urging the holder. A carriage driving mechanism of a serial head type recording apparatus having a biasing means for applying tension to the belt, wherein a stopper member is provided corresponding to a position of the holder when the carriage performs a return operation at a constant speed. And the holder is moved in a direction to reduce the distance between the pulleys from the position. Characterized in that it is configured so that it can not.

Further, the carriage driving mechanism of the serial head type recording apparatus of the present invention comprises a belt for moving a carriage on which a serial head for printing on recording paper is mounted, and a driving pulley around which the belt is stretched. And a tension pulley; a driving means for applying a driving force to the driving pulley; a holder provided rotatably for holding the tension pulley and being movable within a predetermined range in a belt passing direction; and urging the holder. In a carriage driving mechanism of a serial head type recording apparatus having a biasing means for applying tension to the belt, a stopper member is provided corresponding to the position of the holder when the carriage performs a printing operation at a constant speed. And the holder is moved in a direction to reduce the distance between the pulleys from the position. Characterized in that it is configured so as not.

In any of the above configurations, when the driving pulley rotates to move the carriage in the scanning direction, the carriage is started to accelerate by the belt being pulled. Then, the holder moves in a direction to reduce the distance between the two pulleys due to the tension generated in the belt, and attempts to take the holder position during the carriage acceleration movement.
Since the stopper member is provided at any of the positions in the above-described configurations, the position of the holder is restricted before the holder position during the acceleration movement, that is, at the position during the constant velocity movement of the carriage or at the position when the carriage is stationary. Is done. Therefore, the return movement of the holder when the carriage shifts from the acceleration movement to the constant velocity movement is eliminated or slight, so that the position change of the holder is prevented. As a result, the fluctuation of the position of the carriage fixed to one point of the belt (that is, the position of the serial head) is also limited,
The line head deviation of each line is reduced.

Of course, since the tension pulley is not fixed but has a structure provided with an urging means, even if the distance between the two pulleys and the belt length vary, a predetermined tension is applied to the belt. Will be given.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. For convenience of explanation, FIGS. 1 and 2 used in the conventional example are used again here.

FIG. 1 is a perspective view showing a main part of a general serial head type recording apparatus. This serial head type recording apparatus has a recording paper 10 (not shown in this figure).
See FIG. ) And a pinch roller 1b which is provided in opposition to the conveying roller 1a and pinches the recording paper with the conveying roller 1a. A platen 2 disposed, a paper feed roller 8 for feeding the leading end of the recording paper to the paper transport roller unit 1, a pulse motor (not shown) that rotates a predetermined angle in accordance with a pulse, and a rotational force of the pulse motor Gear group 3 for transmitting the recording paper to the transport roller 1a and the paper feed roller 8, a thermal type serial head 4 for printing on the recording paper 10, and a head support 15 for supporting the serial head 4. 2 is attached, the ink ribbon cassette 6 set in the carriage 5 and the carriage 5. 5 and shaft 7 to guide the transverse direction of the recording paper, and a paper feed plate 12 where the recording paper is placed.

FIG. 2 is an explanatory view showing a general printing mechanism. The recording paper 10 is located between the serial head 4 and the platen 2. The ink ribbon 6a of the ink ribbon cassette 6 is interposed between the recording paper 10 and the serial head 4. The serial head 4 and the ink ribbon cassette 6 move in the left direction (carriage scanning direction) in FIG. 2, and the ink ribbon 6a is fed out from the paper feed side roll 6b and wound up by the wind side roll 6c. Then, when one line is printed, the transport roller 1a is driven, and the recording paper 10 is moved by the line feed width (that is, line feed is performed).

FIG. 3 is a schematic diagram showing a carriage driving mechanism according to the embodiment of the present invention. The carriage 5 is fixed to a belt 50, and is moved by being guided by the shaft 7 by the movement of the belt 50. The belt 50 is stretched around a driving pulley 51 and a tension pulley 52. The driving pulley 51 is
A driving force of a driving pulse motor (not shown) is obtained through a gear system (not shown), and the belt 50 is rotated to move the belt 50.

FIG. 4 is a plan view showing components on the tension pulley 52 side in the carriage drive mechanism according to the embodiment of the present invention. The tension pulley 52 is rotatably supported by a tension pulley shaft 53a of a holder 53, and the holder 53 can be moved in a notch portion (not shown) formed in the chassis 54 in a belt passing direction within a predetermined range. It has become. And, between the bent portion 54a of the chassis 54 and the holder 53,
The spring 55 is contracted, and the holder 53 is
It is urged in the direction of pulling zero.

A stopper member 57 is attached to the chassis 54 with a screw 58. The stopper member 57 allows the spring 55 in the holder 53 to be mounted.
The movement in the direction to shrink is restricted.

Here, the position of the holder 53 and the position when it is moved in the direction of reducing the distance between the pulleys 51 and 52 include the following and the following are the positions where the distance is reduced most. .

The position of the holder 53 when the drive pulley 51 is not driven, that is, when the carriage 5 is stationary with the head released. The position of the holder 53 during return and when the carriage 5 is moving at a constant speed. The position of the holder 53 during printing and when the carriage 5 is moving at a constant speed. The position of the holder 53 at the start of printing and when the carriage 5 performs an acceleration motion.

The stopper member 57 is provided with the holder 53 corresponding to the above-mentioned position, the above-mentioned position, or the above-mentioned position. , 52 so as not to move in the direction of shortening the distance between them.
b. When attaching the stopper member 57 corresponding to the above-mentioned position, the stopper member 5 is set in a state where the carriage 5 is stationary.
Since the stopper surface 7 may be attached so as to be in contact with the surface 53b of the holder 53, assembly is most easily performed. on the other hand,
The stopper member 57 corresponding to the above or
It is conceivable to actually move the carriage 5 at a constant speed, mark the position of the holder 53 at that time, and attach the stopper member 57 using the mark as a mark.

In the above configuration, when the driving pulley 51 rotates clockwise in FIG. 3 to move the carriage 5 in the scanning direction, the carriage 5 tends to move by being pulled by the belt 50. Immediately before the movement, the tension pulley 52 cannot rotate, and the upper portion of the belt 50 is loosened by the rotation of the driving pulley 51.
The holder 53 moves in a direction away from the stopper member 57 by the urging. When the carriage 5 starts moving and starts accelerating, the holder 53 moves in a direction to reduce the distance between the pulleys 51 and 52 due to the tension generated in the belt 50, and tries to move to the above-described position. However, since the position at which the stopper member 57 is provided is a position corresponding to any of the above-described positions on the near side of the above-described position, the holder 53 is provided with the stopper member 5.
It hits 7 and cannot move any further. That is, the holder 53 is positioned at the position regulated by the stopper member 57.

Therefore, the return movement of the holder 53 when the carriage 5 shifts from the acceleration movement to the constant velocity movement is eliminated or slight, and the position change of the holder 53 is prevented. Thus, the fluctuation of the position of the carriage 5 (that is, the position of the serial head 4) is also restricted, and the head deviation of each line is reduced.

Here, when the holder 53 is fixedly provided, that is, when the distance between the two pulleys 51 and 52 is fixed, the same effect as described above can be obtained. However, since the tension of the belt 50 is determined by the elongation of the belt being pulled by the distance between the two pulleys 51 and 52 when the belt 50 is fixed, the length of the belt 50 and the length of the fixed distance are determined. It is directly affected by the variation. The fluctuation of the set value of the belt tension is related to the occurrence of jitter which is one of the causes of image quality deterioration. On the other hand, according to the present invention, since the tension is applied by the spring 55, the above-described effect can be obtained, and no trouble occurs when the holder 53 is fixed.

[0032]

As described above, according to the present invention, a change in the position of the holder is prevented, whereby a change in the position of the carriage fixed to one point of the belt, that is, the position of the serial head is also limited. As a result, there is an effect that the head deviation of each line is reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a general serial head type recording apparatus.

FIG. 2 is an explanatory view showing a general printing mechanism.

FIG. 3 is a schematic diagram showing a carriage driving mechanism according to the embodiment of the present invention.

FIG. 4 is a plan view showing components on a tension pulley side in the carriage drive mechanism according to the embodiment of the present invention.

FIG. 5 is a schematic view showing a conventional carriage driving mechanism.

FIG. 6 is a plan view showing components on a tension pulley side in a conventional carriage driving mechanism.

FIG. 7 is an explanatory diagram showing irregularities in cueing of each line in conventional printing.

[Explanation of symbols]

 4 Serial Head 5 Carriage 7 Shaft 10 Recording Paper 15 Head Support 50 Belt 51 Drive Pulley 52 Tension Pulley 53 Holder 54 Chassis 55 Spring 57 Stopper Member

Claims (3)

[Claims] A belt for moving a carriage to which a serial head for printing on recording paper is attached;
A driving pulley and a tension pulley around which the belt is wound, a driving means for applying a driving force to the driving pulley, and the tension pulley rotatably held and movably provided in a belt crossing direction within a predetermined range. In a carriage driving mechanism of a serial head type recording apparatus comprising a holder and an urging means for urging the holder to apply tension to the belt, the carriage driving mechanism corresponds to a position of the holder when the carriage is stationary. A carriage driving mechanism for a serial head type recording apparatus, wherein a stopper member is provided to prevent the holder from moving in a direction for reducing the distance between the pulleys from the position. 2. A belt for moving a carriage to which a serial head for performing printing on recording paper is attached;
A driving pulley and a tension pulley around which the belt is wound, a driving means for applying a driving force to the driving pulley, and the tension pulley rotatably held and movably provided in a belt crossing direction within a predetermined range. In a carriage driving mechanism of a serial head type recording apparatus comprising a holder and an urging means for urging the holder to apply tension to the belt, the carriage driving mechanism includes: A stopper member is provided corresponding to the position, and the holder is configured so as not to move in a direction to reduce the distance between the two pulleys from the position, and the stopper member is configured to be unable to move. Carriage drive mechanism. 3. A belt for moving a carriage to which a serial head for performing printing on recording paper is attached;
A driving pulley and a tension pulley around which the belt is stretched, a driving means for applying a driving force to the driving pulley, and a tension pulley rotatably held and movable within a predetermined range in a belt bridging direction. In a carriage driving mechanism of a serial head type recording apparatus comprising a holder and an urging means for urging the holder to apply tension to the belt, the holder when the carriage performs a printing operation at a constant speed motion. And a stopper member is provided corresponding to the position of the serial head type recording apparatus, wherein the holder cannot move in the direction of reducing the distance between the two pulleys from the position. Carriage drive mechanism.