JP3948178B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus that records an image by ejecting ink from a nozzle portion onto recording paper based on image information.
[0002]
[Prior art]
In general, as shown in FIG. 6, the inkjet recording apparatus 100 includes a recording head 104 mounted on a carriage 102, and serially scans the carriage 102 to record characters and images on a recording medium P.
[0003]
As a configuration for serially scanning the carriage 102, generally, an endless timing belt 112 is wound between a driving pulley 108 and a driven pulley 110 connected to a motor 106, and the carriage 102 is connected to the timing belt 112. A method is used in which the carriage 102 is reciprocated along guide rails 116 and 118 fixed to the main body frame 114 by driving the motor 106 forward and backward.
[0004]
Here, in order to apply a certain amount of tension to the timing belt 112, the main body frame 114 is provided with a notch 120, and the support member 122 to which the driven pulley 110 is attached can slide in the notch 120. Has been placed.
[0005]
On the other hand, as shown in FIG. 7, a pair of rails 122A and 122B are erected from the upper and lower surfaces 122C of the support member 122, and the main body frame 114 is sandwiched between the rails 122A and 122B. Slide against the main body frame 114.
[0006]
The support member 122 is urged by a spring 124 so that the driven pulley 110 can move along the center line L between the timing belts 112 facing each other. At this time, the spring 124 is arranged so that the rotation center O of the driven pulley 110 is on the center line L of the urging force.
[0007]
In such a configuration, when the weight of the carriage 102 increases (for example, when the number of mounted recording heads 104 increases, the volume of the ink tank increases, or when the carriage 102 pulls the ink supply tube) For example, when the scanning speed is increased, the output torque of the motor 106 is increased and the tension of the timing belt 112 is increased.
[0008]
However, generally, when the output torque of the motor 106 is increased, the vibration of the timing belt 112 and the like is increased accordingly, and noise due to this vibration is generated. This tendency is large when a stepping motor is used as the motor.
[0009]
In addition, as shown in FIG. 8, the weight of the carriage 102 increases in an acceleration region where the carriage 102 is suddenly accelerated from a stopped state to a constant speed region, or in a deceleration region where the carriage 102 is suddenly decelerated so as to be suddenly stopped from the constant speed region. As a result, shocking vibration is generated and noise is likely to be generated.
[0010]
On the other hand, as shown in FIG. 7, when the tension of the timing belt 112 is increased, the rotational moment generated in the support member 122 when the driven pulley 110 rotates increases, and the support member 122 is driven by the reciprocating movement of the carriage 102. 110 moves around in the direction of the arrow, and the upper and lower surfaces 122C of the support member 122 come into contact with the notch 120 to generate noise.
[0011]
As a countermeasure for this problem, a ball bearing is used for the shaft portion 126 of the driven pulley 110 so that the support member 122 does not rotate and the support member 122 does not swing when the driven pulley 110 rotates. Although it can be considered, the use of ball bearings increases the cost.
[0012]
A method of reducing the gap t between the support member 122 of the driven pulley 110 and the main body frame 114 and preventing the support member 122 from swinging is also conceivable. However, since the component accuracy must be improved, the cost increases.
[0013]
[Problems to be solved by the invention]
In view of the above facts, it is an object of the present invention to provide an ink jet recording apparatus that prevents the support member of the driven pulley from swinging and reduces noise when the carriage reciprocates.
[0014]
[Means for Solving the Problems]
According to the first aspect of the present invention, ink is ejected from the nozzle portion onto the recording paper based on the image information by the recording head, and an image is recorded. The recording head is held by a carriage, and the carriage is supported by a shaft fixed to the main body frame, and can move in a direction orthogonal to the conveyance direction of the recording paper.
[0015]
Further, a belt is fixed to the carriage, and a pulley is wound around the belt. When a driving force is transmitted to the pulley by a driving source, the carriage moves through the belt.
[0016]
The pulley is rotatably supported by a support member, and a pair of guide portions are formed on the support member above and below the shaft portion of the pulley. On the other hand, a notch for guiding the guide portion is formed in the main body frame along the extending direction of the belt, and the support member can be moved along the direction in which the belt extends. The support member is urged by the urging means in a direction in which the belt extends, and is rotated about the pulley to be inclined, and the guide portion of the support member is brought into contact with the notch portion of the main body frame.
[0017]
In this way, the support member is not rocked even when the rotational moment generated on the support member is increased when the pulley rotates by inclining the support member with the main body frame by the biasing means. . For this reason, it is possible to prevent vibration and noise due to the swinging of the support member.
[0018]
Therefore, the scanning speed can be increased and the throughput (image recording efficiency) is improved. Further, the volume of the ink tank mounted on the carriage can be increased, and the operability can be improved by reducing the ink replacement frequency.
[0019]
In the invention according to claim 2, the urging means is arranged so that the center line of the urging force does not pass through the rotation center of the pulley.
[0020]
For this reason, a rotational force is applied to the support member in advance, and the support member can be tilted and brought into contact with the main body frame to prevent the support member from swinging. In this way, merely by changing the arrangement of the urging means, the pulleys are prevented from swinging, so that the cost is not increased.
[0021]
In the invention according to claim 3, the amount of deviation δ between the center line between the opposing belts and the center line of the urging force satisfies the following expression.
[0022]
δ> 1/2 μd (1 + ma / gN)
Where μ is a coefficient of friction generated in the shaft support portion of the pulley, d is the shaft diameter of the pulley, m is the weight of the carriage, a is the maximum acceleration of the carriage, N is the urging force by the urging means, and g is the gravitational acceleration. .
[0023]
In the invention according to the fourth aspect, the deviation amount δ satisfies the following expression.
[0024]
δ> μd (1 + ma / gN)
[0025]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an ink jet recording apparatus 10 according to this embodiment.
[0026]
The ink jet recording apparatus 10 is provided with a pair of L-shaped main body frames 12 and 14 along the conveyance direction of the recording medium P. Two guide rails 16, 18 are fixed in parallel to the main body frames 12, 14 perpendicular to the conveyance direction of the recording medium P.
[0027]
A carriage 20 on which a recording head 22 is mounted is attached to the guide rails 16 and 18 and can slide along the guide rails 16 and 18.
[0028]
A bending wall 12A is bent at a right angle on the main body frame 12, and a carriage motor 24 as a driving source is fixed to the bending wall 12A. The carriage motor 24 can be driven forward and backward.
[0029]
A main driving pulley 26 is directly connected to the carriage motor 24, and the main driving pulley 26 rotates forward and backward in accordance with the forward and reverse driving of the carriage motor 24.
[0030]
On the other hand, a folding wall 14A is bent at a right angle on the main body frame 14, and a driven pulley 28 described later is provided. A timing belt 30 is wound around the driven pulley 28 and the main driving pulley 26 in parallel with the guide rails 16 and 18, and the driving force transmitted from the carriage motor 24 is transmitted to the driven pulley 28 via the timing belt 30. Is done.
[0031]
The timing belt 30 is connected to the carriage 20 by a fixed portion 32. For this reason, the fixed portion 32 of the timing belt 30 reciprocates in a direction orthogonal to the conveyance direction of the recording medium P in accordance with forward and reverse driving of the carriage motor 24.
[0032]
Along with this, the carriage 20 reciprocates along the guide rails 16 and 18, and the carriage 20 performs serial scanning to record characters and images on the recording medium P.
[0033]
Here, as shown in FIG. 2, a notch 34 is formed in the bending wall 14 </ b> A of the main body frame 14 along the extending direction of the timing belt 30. A support member 36, which will be described later, is disposed in the notch 34, and is movable along the notch 34.
[0034]
A pair of guides 37, 39 are erected from the upper and lower surfaces 36 </ b> A of the support member 36, and a gap w is provided between the guide 37 and the guide 39. This gap w is slightly wider than the thickness of the bent wall 14A.
[0035]
For this reason, the bending wall 14A is sandwiched between the guide 37 and the guide 39, and the support member 36 is moved relative to the bending wall 14A. Note that the guides erected from the lower surface 36 </ b> A of the support member 36 have the same structure and are omitted because other main parts are difficult to understand.
[0036]
Further, a notch 41 is provided in the central portion of the support member 36 along the longitudinal direction so that the driven pulley 28 can be inserted. In the cut 41, a long groove 41A having a narrow width toward the back of the cut 41 is formed. A shaft portion 28A fixed to the driven pulley 28 is attached to the long groove 41A, and is rotatably supported behind the long groove 41A.
[0037]
Further, a mounting portion 35 to be described later protrudes from the support member 36, and one end side of a compression spring 38 can be mounted on the mounting portion 35. On the other hand, a pedestal 14B is erected at the tip of the bent wall 14A, and the other end of the compression spring 38 is supported.
[0038]
The compression spring 38 biases the support member 36 along the notch 34 in the direction of arrow A. As a result, the driven pulley 28 moves in a direction away from the main pulley 26 (see FIG. 1) via the shaft portion 28A that is pivotally supported by the support member 36.
[0039]
For this reason, the distance between the driven pulley 28 and the main pulley 26 is increased, and tension is applied to the timing belt 30. As described above, since the tension is applied to the timing belt 30, there is no rattling even when the scanning speed is increased.
[0040]
In addition, since the driven pulley 28 is movable with respect to the bending wall 14A via the support member 36, it is possible to cope with the elongation due to the temporal change of the timing belt 30.
[0041]
Here, as shown in FIG. 3, the shaft core of the mounting portion 35 is displaced from the center line R of the driven pulley 28 (deviation amount δ), and one end portion of the compression spring 38 is attached to the mounting portion 35. When the end portion is supported by the base 14 </ b> B, the axial core line Q of the compression spring 38 is displaced from the center line R of the driven pulley 28.
[0042]
In this way, by placing the compression spring 38 on the support member 36 in a state where the axis Q of the compression spring 38 is displaced from the center line R of the driven pulley 28, a rotational force is applied to the support member 36 in advance. As shown in FIG. 4, the support member 36 is inclined, and the upper and lower surfaces 36 </ b> A of the support member 36 abut against the notch 34.
[0043]
For this reason, by applying tension to the timing belt 30, even if the rotational moment generated between the shaft portion 28A and the support member 36 when the driven pulley 28 rotates, the support member 36 does not swing. Absent. Therefore, it is possible to prevent vibration and noise due to the swinging of the support member 36.
[0044]
Further, since the support member 36 does not swing, it does not rattle even when the scanning speed is increased, and the throughput is improved. Furthermore, the volume of the ink tank mounted on the carriage 20 can be increased, and the operability can be improved by reducing the frequency of ink replacement.
[0045]
On the other hand, the deviation δ ₁ based on the theoretical value is experimentally determined.
δ ₁ > 1/2 μd (1 + ma / gN)
It has been confirmed that. Here, μ is a friction coefficient generated in the shaft portion 28A of the driven pulley 28, and in this experiment, μ = 0.25. d is the shaft diameter of the shaft portion 28A, and d = 4 mm.
[0046]
Further, m is the weight of the carriage 20, m = 0.9 kg, a is the maximum acceleration of the carriage 20, and a = 9.8 m / s ² . Further, N is an urging force by the compression spring 38, N = 3 Kg, and g is 9.8 m / s ² in terms of gravitational acceleration.
[0047]
As a result, δ ₁ = 0.65 mm is obtained. δ but is large enough swing effective in preventing the support member 36, the safety factor of the mu, considering the size of the dispersion, and the like, and an ink jet recording apparatus 10 of the dimensions of each component δ is about 2.delta. ₁ is desirable.
[0048]
For this reason, δ = 2 μd (1 + ma / gN), and when the experiment was actually performed with δ = 1.3 mm, the rocking of the support member 36 was completely prevented, and the noise of the inkjet recording apparatus 10 was reduced.
[0049]
Here, a rotational force is preliminarily applied to the support member 36 by shifting the axis Q of the compression spring 38 from the center line R of the driven pulley 28, and the support member 36 is inclined to form the bent wall 14A. However, the present invention is not limited to this.
[0050]
For example, the spring may be of a tension type, the rotational moment given to the support member 36 in advance may be reversed, and may be appropriately selected according to space, cost, use conditions, and the like.
[0051]
【The invention's effect】
Since the present invention is configured as described above, in the first aspect of the present invention, the rotation moment generated on the support member when the pulley rotates by inclining the support member and contacting the main body frame by the biasing means. Even if becomes larger, the support member does not swing. For this reason, it is possible to prevent vibration and noise due to the swinging of the support member. Therefore, the scanning speed can be increased and the throughput is improved. Further, the volume of the ink tank mounted on the carriage can be increased, and the operability can be improved by reducing the ink replacement frequency. According to the second aspect of the present invention, a rotational force is applied to the support member in advance, and the support member can be tilted and brought into contact with the main body frame to prevent the support member from swinging. In this way, merely by changing the arrangement of the urging means, the pulleys are prevented from swinging, so that the cost is not increased.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an ink jet recording apparatus according to the present embodiment.
FIG. 2 is an exploded perspective view showing a support member and a driven pulley used in the ink jet recording apparatus according to the present embodiment.
FIG. 3 is a front view showing the arrangement of support members and urging means used in the ink jet recording apparatus according to the present embodiment.
FIG. 4 is a front view showing a state in which a rotational force is applied to a support member used in the ink jet recording apparatus according to the present embodiment.
FIG. 5 is a horizontal sectional view showing a support member and an urging means used in the ink jet recording apparatus according to the present embodiment.
FIG. 6 is a perspective view showing a conventional inkjet recording apparatus.
FIG. 7 is a front view showing the arrangement of support members and biasing means used in a conventional ink jet recording apparatus.
FIG. 8 is a graph showing an acceleration / deceleration state of a carriage.
[Explanation of symbols]
10 Inkjet recording device 14B Pedestal (biasing means)
34 Notch 35 Mounting part (biasing means)
36 Support members
37 Guide (guide section )
38 Compression spring (biasing means)
39 Guide (guide section)

Claims (4)

A carriage that holds a recording head that discharges ink from a nozzle portion to recording paper based on image information and records an image, and a shaft that supports the carriage so as to be movable in a direction orthogonal to the conveyance direction of the recording paper A main body frame to which the shaft is fixed, a belt fixed to the carriage, a pulley around which the belt is wound and the carriage can be moved via the belt, and a drive for transmitting a driving force to the pulley An inkjet recording apparatus comprising: a source;
A support member in which the pulley is rotatably supported and a pair of guide portions are formed above and below the shaft portion of the pulley;
A notch portion that is formed in the main body frame along the extension direction of the belt and guides the guide portion;
Urging means for urging the support member in a direction in which the belt extends and rotating the pulley about the pulley to incline it and abut against the body frame;
An ink jet recording apparatus comprising:   2. The ink jet recording apparatus according to claim 1, wherein the urging unit is arranged so that a center line of the urging force does not pass through a rotation center of the pulley. 3. The ink jet recording apparatus according to claim 1, wherein a deviation amount δ between a center line between the opposed belts and a center line of the urging force satisfies the following expression.
δ> 1/2 μd (1 + ma / gN)
Where μ is a coefficient of friction generated in the shaft support portion of the pulley, d is the shaft diameter of the pulley, m is the weight of the carriage, a is the maximum acceleration of the carriage, N is a biasing force by the biasing means, and g Is the gravitational acceleration. The inkjet recording apparatus according to claim 3, wherein the deviation amount δ satisfies the following expression.
δ> μd (1 + ma / gN)

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