JPH1035052A - Carriage driving mechanism for printer and adjusting method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold a carriage position with respect to a lead groove at a certain position by supporting a pin such that the amount to engage with the lead groove of the pin for moving the carriage reciprocally can be adjustable. SOLUTION: A carriage driving pin 7 is fitted into a hole 3c provided at the center of a cylindrical pin holder 3. The pin holder 3 fitted with the pin 7 is inserted to a hole 12a of a pin holder receiving portion 12. A spiral cam 3a is formed at an end portion of the pin holder 3. A similar spiral cam is also formed at the bottom of the hole 12a of the pin holder receiving portion 12. An L-shaped arm portion 3d is provided at a side face of the pin holder 3. An engaging pawl 3b is provided at the tip of the arm portion 3d. On the other hand, a plurality of grooves 12c are provided on a part of the outer wall of the pin holder receiving portion 12 with an equal pitch. The engaging pawl 3b engages with one of the grooves 12c so as to limit the rotation of the pin holder 3. Accordingly, the carriage driving pin 7 can be held at a certain position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer for printing characters, figures and the like while moving a print head in a digit direction, and more particularly to a print head feed mechanism.

[0002]

2. Description of the Related Art A prior art in which a carriage driving mechanism for reciprocating a carriage includes a carriage on which pins are disposed and a carriage driving shaft having a lead groove of a predetermined lead amount which engages with the pins and rotates. For example, JP 05
As shown in -169647, one end formed into a spherical shape is slidably fitted in a hole formed in the carriage body perpendicularly to the axial direction of the carriage drive shaft, and the other end is fitted in the lead groove of the carriage drive shaft. 2. Description of the Related Art A printer is known in which a carriage is reciprocated by a pin whose end is biased by a spring.

In such a printer, the amount of movement of the carriage in the direction of the carriage drive shaft is set by utilizing the fact that it is proportional to the rotation angle of the carriage drive shaft. Therefore, a print head mounted on the moving carriage is driven. The lead of the carriage drive shaft is made so that the amount of displacement in the axial direction with respect to the rotation angle is precisely constant so that the obtained printing interval is constant with high accuracy, and the carriage is faithfully moved to the lead. This is necessary in order to obtain a printing result in which the intervals between adjacent printed dots in the digit direction are equal (the accuracy of the printing interval is high) and density between dots does not occur.

[0004]

Problems to be solved by the present invention will be described below with reference to FIGS. 3 and 4.
FIG. 3 is a side sectional view of a carriage driving mechanism according to the related art.
FIG. 4 is a diagram showing the direction of the force applied to the pins in the carriage driving mechanism.

[0005] In the structure employed in the above-described conventional printer, in which the carriage is driven by transmitting the position change of the lead groove of the carriage drive shaft to the carriage by a pin, the force for moving the carriage is transmitted as shown in FIG. 4B. Since the pin is in spherical contact with the lead groove of the carriage drive shaft, it receives a component force perpendicular to the moving direction of the carriage. In the conventional printer described above, the other end of the pin is urged by a spring 11 as shown in FIG. 3 to prevent the pin from coming off the lead due to this component force.

However, since the component force in the direction perpendicular to the moving direction of the carriage increases and decreases in proportion to the driving force of the carriage drive shaft, the spring expands and contracts in accordance with the increasing and decreasing vertical component force when the pin is urged by the spring force. Since the position of the pin fluctuates, the position of the pin cannot be kept constant with respect to the lead groove. This situation will be described in detail with reference to FIGS.

FIG. 4A shows a case where no driving force is applied to the pins from the carriage driving shaft. At this time, the center axis of the lead groove coincides with the center axis of the pin. On the other hand, FIG. 4B is a diagram in the case where a small driving force is acting on the pin from the carriage driving shaft. In this case, the center axis of the lead groove and the center of the pin are maintained until the force in the pin biasing spring force direction A is balanced. The axis is shifted. Further, FIG. 4c is a diagram in the case where a large driving force is applied to the pin from the carriage driving shaft. In this case as well, the pin is moved along the wall of the lead groove until the force in the pin biasing spring force direction A is balanced. Since the position is shifted, the center axis of the lead groove and the center axis of the pin are largely shifted.

The positional deviation between the center axis of the pin and the lead groove generated as described above has a great influence on the print quality in a high-definition printing method such as an ink jet recording method which has recently become popular. . In addition, 360D which is a general printing density in the ink jet recording system is used.
In PI (print density for printing 360 dots per inch), the dot interval is 0.07 mm, and the required print position accuracy is 0.035 mm.

The magnitude of the force in the above description is an expression representing the relative relationship with the pin urging spring force, and is not an absolute value. Also, the description has been given of the example of the variation in the driving force of the carriage drive shaft.
This phenomenon is caused not only when the carriage drive shaft is accelerated, decelerated, or when rotation unevenness occurs, but also when fine dust such as paper dust that enters between the pin and the carriage drive shaft, changes in friction resistance due to uneven lubrication, In the case of a print head, it also occurs due to fluctuations in the amount of ink.

In the mechanism for urging the pins by the spring force, it is difficult to keep the carriage position relative to the lead groove, that is, the head position, at a constant position. There is a problem that the quality is not stable.

Further, in recent years, it has been desired that the printing speed of the printer be increased. However, rotating the carriage driving shaft at a high speed increases the driving force of the carriage driving shaft. As a result, speeding up is limited.

As a countermeasure against these problems, it is conceivable to increase the spring force. However, since the driving force must be increased to counter the inevitably increasing friction between the pin and the carriage drive shaft, the motor is increased in size and the power supply circuit is increased. This is a major problem in printers that require large size and are desired to be small and lightweight. Further, increasing the spring force promotes wear of the pins and lead grooves, reduces the durability of the printer, and causes an increase in sliding noise.

Although a method of fixing the pins to the carriage is also conceivable, slight fluctuations in the dimensions of the carriage drive shaft, the carriage and the pins themselves are unavoidable during mass production. Pins bite into the carriage drive shaft and cannot be used in practice.

SUMMARY OF THE INVENTION The present invention has been made to solve such a drawback, and an object of the present invention is to provide a high-speed printing capable of stably obtaining a high-precision printing quality, a high-quietness, small-size printer. Is to provide.

[0015]

In order to solve the above-mentioned problems, the present invention relates to a helical drive mechanism for a printer for printing on recording paper while moving a carriage having a print head along a platen. A carriage drive shaft provided with a lead groove and rotatably supported; a pin engaged with the lead groove to reciprocate the carriage with rotation of the carriage drive shaft; and the pin is engaged with the lead groove. And a pin supporting means for supporting the pin so as to adjust the amount to be combined.

According to the configuration of the present invention, the tip of the pin can be set at an optimum position with respect to the lead groove. Therefore, it is not necessary to use an elastic body conventionally required for mounting the pin, and therefore, a rigid component receives a component force in a direction perpendicular to the moving direction of the carriage to be received by the pin. The position of the pin can be kept constant with respect to the lead groove irrespective of the size of the lead groove. Therefore, the position of the carriage relative to the lead groove, that is, the position of the head, is determined with high accuracy, and the printing quality is stabilized. Furthermore,
Even when the carriage driving shaft is rotated at a high speed to increase the printing speed and the force received by the pin from the lead groove increases, the position of the pin does not change with respect to the lead groove. Therefore, compared to the conventional pin that was held by an elastic body,
According to the present invention, since the friction between the pin and the drive shaft does not increase according to the rotation speed of the drive shaft,
Even when the rotation speed is increased, the wear of the pins and the lead grooves does not progress, the durability of the printer is not reduced, and the sliding noise between the pins and the carriage drive shaft is not increased. Further, since it is not necessary to use a motor having a higher torque in order to oppose the frictional force, it is also effective in reducing the size and weight of the printer.

Further, since the amount of engagement of the lead groove of the pin can be changed, minute fluctuations in dimensions of the carriage drive shaft and the carriage and the pin itself, which are inevitable for mass-produced parts, can be adjusted, and parts of any size can be adjusted. Even with the combination, there is no occurrence of rattling due to an insufficient amount of engagement and no biting of the pin to the carriage drive shaft due to an excessive amount of engagement.

According to the second aspect of the present invention, the pin supporting means movably supports the pin in a direction of engaging and disengaging the lead groove, and supports the moving pin. By holding in place, the amount by which the pin engages the lead groove can be adjusted.

Further, according to the invention of claim 3, according to claim 2,
In the carriage driving mechanism of the printer, the pin is rotatably held with respect to the pin supporting means, and along with the rotation, along the spiral cam provided on the pin or the pin supporting means, By configuring the pin to move in the direction of engaging and disengaging the lead groove, the amount of engagement of the pin with the lead groove can be adjusted only by rotating the pin.

According to a fourth aspect of the present invention, in the carriage driving mechanism for a printer according to the third aspect, a plurality of grooves are provided on an outer periphery of the pin support means, and a side portion of the pin is provided. The claw fixed to the pin selectively engages with one of the plurality of grooves and holds the pin at a predetermined position, thereby reliably holding the position of the pin adjusted to an appropriate engagement amount. be able to.

According to a sixth aspect of the present invention, in the method for adjusting the carriage driving mechanism of the printer according to the fourth aspect, the method for adjusting the carriage driving mechanism of the printer is provided in the direction in which the lead groove is engaged. After rotating the pin and bringing the tip of the pin into contact with the lead groove, rotating the pin in a direction to separate from the lead groove, the claw fixed to the side of the pin is A plurality of grooves provided on the outer periphery of the pin supporting means are engaged in grooves exceeding a predetermined number of grooves to fix the position of the pin with respect to the lead groove. As described above, by confirming the positions of the plurality of grooves provided on the outer circumference of the pin supporting means with the claws, the position of the tip of the pin, that is, the engagement of the pin with the lead groove is confirmed. The amount can be adjusted easily and accurately, and there is no need to use a troublesome jig. As described above, according to the present invention, it is possible to provide a small, lightweight printer with high quietness and high quietness, which can stably obtain high-precision printing quality.

[0022]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view of a carriage driving mechanism according to the present invention, and FIG. 2 is a schematic plan view of an embodiment of a printer using the present invention.

As shown in FIG. 2, the carriage drive shaft 6 having spiral lead grooves 6a of equal pitch formed on the outer periphery thereof is
The frame 5 is rotatably supported. A gear 10 is fixed to one end of the drive shaft 6, and the rotation of the motor 8
The power is transmitted to the drive shaft 6 via the gears 9 and 10. The carriage 1 on which the print head 2 is mounted is supported by a guide shaft (not shown) so as to be able to move in the beam direction. A pin holder receiving portion 12 that rotatably supports the pin holder 7 in which the carriage driving pin 7 is fitted is provided on a side portion of the carriage 1.
Are provided integrally. The tip of the pin 7 engages with the lead groove 6a of the drive shaft 6, rotates the motor 8 forward and reverse, and rotates the drive shaft 6 forward and reverse in the B and D directions, whereby the pin 7 moves along the lead groove 6a. By moving, the carriage 1 also moves along the recording paper 4 in the digit direction (E and F directions). The print head 2 is connected to a control board (not shown) by an FPC (not shown), and prints on the recording paper 4 by energizing the print head 2 at a desired timing.

After the desired printing has been performed, the carriage 1 is stopped and moved in the F direction to return to the standby state. After this,
The paper feed operation is started, and the recording paper 4 is fed by a predetermined amount in the row direction by a paper feed mechanism (not shown), and the printing operation is completed.

In the series of operations, in order to drive the carriage 1 in the girder direction, it is already necessary that the carriage pin 7 be in contact with the slope of the lead groove 6a of the carriage drive shaft 6. As described with reference to FIG. 4, the center axis 7a of the carriage pin does not coincide with the center axis 6b of the lead groove 6a when the carriage is driven.

A carriage driving pin of a carriage driving mechanism of a printer according to the present invention and a pin holder for supporting the same will be described below mainly with reference to FIG.

The carriage driving pin 7 is fitted into a hole 3c provided at the center of the cylindrical pin holder 3. Pin 7
Is inserted into the hole 12 a of the pin holder receiving portion 12. The diameter of the hole 12a is
-The size of the receiving portion 12 is set such that there is no backlash and the holder 3 can rotate smoothly.

The pin holder 3 has a helical cam 3a formed at an end thereof, and a similar helical cam 1a is formed at the bottom of the hole 12a of the pin holder receiving portion 12. When the pin holder 3 is mounted on the receiving portion 12a, the helical cams 1a and 3a abut and engage with each other. By rotating the pin holder 3, the pin holder 3 moves with the carriage drive pin 7 in the axial direction. That is, when the pin holder 3 is rotated in the G direction, the pin 7 moves forward, and when rotated in the H direction, the pin 7 moves backward.

An L-shaped arm 3d is provided on the side surface of the pin holder 3, and an engagement claw 3b is provided at the tip of the arm 3d. The engaging claw 3b has a triangular cross section. On the other hand, on a part of the outer wall of the pin holder receiving portion 12, a plurality of grooves 12c are provided at an equal pitch. The engaging claw 3b functions to regulate the rotation of the pin holder 3 and hold it at a fixed position by engaging with any one of the grooves 12c. That is, the engaging claw 3b and the groove 12c
, The carriage drive pin 7 is held at a predetermined position. When the pin 3 is rotated by pinching the arm 3d by hand, the arm 3d is deformed upward, and the engaging claw 3b goes over the mountain between the adjacent grooves 12c and engages with the adjacent groove. .

As described above, by rotating the pin holder 3 and engaging the engaging claw 3b with the predetermined groove, the amount of protrusion of the carriage drive pin 7 from the carriage 1 can be easily changed, and It is possible to adjust the amount of engagement between the carriage pin 7 and the lead groove 6a of the carriage drive shaft 6 due to variations in the dimensions of each component that cannot be avoided during production.

As described above, the carriage driving pins 7
When the amount of protrusion from the carriage 1 is fixed,
The phases of the helical cams 3a and 1a of both the pin holder 3 and the holder receiving portion are fixed, and at this abutting portion, a component force in the direction perpendicular to the moving direction of the carriage 1 received by the driving pin 7 is received. Irrespective of the magnitude of the driving force, the position of the pin can be kept constant with respect to the lead groove.

The spiral lead groove 6 of the carriage drive shaft 6
In order to increase the accuracy of the dot interval (printing interval) between adjacent printed dots in the digit direction, a is precisely formed at a constant pitch so that the amount of displacement in the axial direction is always constant with respect to the rotation angle. In order to reflect the high accuracy on the carriage feed amount, in the present invention, the pin holder 3 is required to perform a printing operation in which the deviation amount between the center axis of the carriage drive pin 7 and the center of the lead groove due to deformation of the pin holder 3 is required. For example, the synthetic resin is made of a material having low elasticity that can be regarded as having substantially no fluctuation due to elasticity so as to fall within a sufficiently small value with respect to the accuracy of the interval.

As a specific example, among synthetic resins used for industrial products, acetal resin can be used, but PA elastomer resin has high elasticity and is not suitable for the material of the carriage pin holder.

Further, the relationship between the pitch of the plurality of grooves 12c provided in the pin holder receiving portion and the magnitude of the inclination of the helical cams 3a, 12b is set to a predetermined value in advance by the printer to be applied, and the engagement claw 3b is set. The unit advance / retreat amount of the carriage drive pin 7 when moving one groove 12c can be optimized. In the present embodiment, the unit advance / retreat amount is 0.1
mm.

In this embodiment, the case where the spiral cam is provided at the end of the pin holder 3 has been described. However, the present invention also includes a configuration in which the spiral cam is provided on the side cylindrical surface of the pin holder 3 which is substantially cylindrical. Included. Further, the present invention includes a configuration in which a male screw is provided on the side cylindrical surface of the pin holder 3 and a female screw is provided on the inner peripheral surface of the hole 12a of the holder receiving portion on the carriage side.

In the above, the case where the helical cams are provided on both the pin holder and the carriage side has been described. However, the present invention includes a configuration in which one of the helical cams is provided and the other is a cam follower.

Hereinafter, a method for adjusting the carriage driving mechanism of the printer according to the present invention will be described with reference to FIG. FIG. 5 shows a plurality of grooves 12 c provided on the outer periphery of the pin holder receiving portion 12.
FIG. 4 is a partial cross-sectional view of an engaging claw 3b of a pin holder 3 that engages with the same.

After attaching the carriage 1 to which the pins 7 and the pin holder 3 are attached to the guide shaft and the carriage drive shaft 6, the tip of the pin 7 and the drive shaft 6 are moved in the following manner.
The amount of engagement with the lead groove 6a is adjusted.

First, the pin holder 3 is rotated in the direction G to bring the tip of the drive pin 7 into contact with the lead groove 6a. At this time, as shown in FIG.
2c is engaged with the groove 12e. Also, in this state,
As shown in FIG. 4A, there is no gap between the drive pin 7 and the lead groove 6a, and there is no play. In this state, a very large torque is required to move the carriage 1, so that a predetermined amount of gap needs to be provided between the drive pin 7 and the lead groove 6a. However, if the gap is too large, it affects the accuracy of the printing interval, as described above, so that it is necessary to adjust the gap with high accuracy.

Therefore, from this state, the pin holder 3 is
By rotating the drive pin 7 in the direction by a predetermined amount, the drive pin 7 is retracted to provide a predetermined amount of clearance between the drive pin 7 and the lead groove 6a.

When the tip of the drive pin 7 contacts the lead groove 6a, the position at which the engaging claw 3b contacts the groove 12e is different due to variations in the processing accuracy, assembly accuracy, etc. of each part.
When the engaging claw 3b is in contact with the wall surface 12h of the groove 12e, the engaging claw 3b is moved to the groove 12f in the H direction by one groove, while the engaging claw 3b is moved toward the wall 12d side of the groove 12e. Dovetail 3
b, the engaging claw 3b is set at H
In the direction up to the groove 12g. Thereby, a gap within a predetermined range is provided between the drive pin 7 and the lead groove 6a.

As described above, the pin holder 3 is rotated with respect to the plurality of grooves provided on the outer periphery of the pin supporting means until the tip of the driving pin 7 once comes into contact with the lead groove 6a. After confirming the state in which the tip of the drive pin 7 is in contact with the lead groove 6a, the amount of engagement of the pin 7 with the lead groove 6a is adjusted with reference to the position of the drive pin 7 based on the position. It can be adjusted accurately and there is no need to use a troublesome jig.

The present invention can be effectively applied to printers of any printing system such as a thermal system and an impact dot system. However, the ink jet system in which the total weight of the carriage changes according to the amount of ink consumed. It is more effective if used for a printer.

[0045]

As described above, according to the present invention, the tip of the pin can be easily and accurately set at the optimum position with respect to the lead groove. Therefore, it is not necessary to use an elastic body conventionally required for mounting the pin, and therefore, a rigid component receives a component force in a direction perpendicular to the moving direction of the carriage to be received by the pin. The position of the pin can be kept constant with respect to the lead groove irrespective of the size of the lead groove. Therefore, the position of the carriage relative to the lead groove, that is, the position of the head, is determined with high accuracy, and the printing quality is stabilized. Furthermore, even if the printing speed is increased and the carriage drive shaft is rotated at a high speed to increase the force applied to the pins from the lead grooves, the positions of the pins do not change with respect to the lead grooves. Therefore, in comparison with the conventional method in which the pin is held by an elastic body, the present invention does not increase the friction between the pin and the drive shaft according to the rotation speed of the drive shaft. Even if the speed is increased, the wear of the pins and lead grooves will not progress and the durability of the printer will not be reduced,
There is no increase in the sliding noise between the pin and the carriage drive shaft.
Further, since it is not necessary to use a motor having a higher torque in order to oppose the frictional force, it is also effective in reducing the size and weight of the printer.

Further, since the amount of engagement of the lead groove of the pin can be changed, minute fluctuations in the dimensions of the carriage drive shaft, the carriage, and the pin itself, which are inevitable for mass-produced parts, are adjusted, and the parts of any size can be adjusted. Even with the combination, there is no occurrence of rattling due to an insufficient amount of engagement and no biting of the pin to the carriage drive shaft due to an excessive amount of engagement.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part of a carriage driving mechanism according to an embodiment of the present invention.

FIG. 2 is a plan view of a carriage driving mechanism of the printer according to the embodiment of the present invention.

FIG. 3 is a side sectional view showing a power transmission unit of a conventional example.

FIG. 4 is an explanatory diagram showing a balanced state of driving force.

FIG. 5 is a partial cross-sectional view of a plurality of grooves provided on the outer periphery of a pin holder receiving portion of the present invention and engaging claws of the pin holder engaging with the grooves.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 carriage 2 print head 3 carriage pin holder 4 recording paper 5 frame 6 carriage drive shaft 7 carriage drive pin 8 motor 9 motor gear 10 carriage drive gear 12 pin holder receiver

Claims (6)

[Claims] 1. A carriage driving mechanism for a printer for printing on recording paper while moving a carriage on which a print head is mounted along a platen, the carriage driving shaft having a spiral lead groove and rotatably supported, A pin that engages with the lead groove and reciprocates the carriage with the rotation of the carriage drive shaft; and pin support means that supports the pin so that the amount of engagement of the pin with the lead groove can be adjusted. And a carriage driving mechanism for the printer. 2. A carriage driving mechanism for a printer according to claim 1, wherein said pin support means movably supports said pin in a direction in which said pin is engaged with and disengaged from said lead groove. A carriage driving mechanism for a printer, which is held at a predetermined position. 3. A carriage driving mechanism for a printer according to claim 2, wherein said pin is rotatably held with respect to said pin supporting means, and is provided on said pin or said pin supporting means with its rotation. A carriage mechanism for the printer, wherein the pin moves in a direction of engaging and disengaging the lead groove along the spiral cam. 4. A carriage driving mechanism for a printer according to claim 3, wherein a plurality of grooves are provided on an outer periphery of said pin supporting means, and a claw fixed to a side portion of said pin is provided with said plurality of grooves. A carriage drive mechanism for a printer, wherein said carriage drive mechanism selectively engages one of said pins to hold said pin in a predetermined position. 5. A carriage driving mechanism for a printer according to claim 1, wherein said print head is an ink jet head. 6. A method for adjusting a carriage driving mechanism of a printer according to claim 4, wherein said pin is rotated in a direction in which said pin engages with said lead groove, and said tip of said pin contacts said lead groove. Rotating the pin in the direction of detaching from the lead groove, and moving the claw fixed to the side of the pin beyond a predetermined number of grooves among a plurality of grooves provided on the outer periphery of the pin supporting means. A method of adjusting a carriage driving mechanism of a printer, wherein the position of the pin relative to the lead groove is fixed by being locked in a groove of a position.