JP3064721U - Inkjet printer - Google Patents

Abstract

(57) Abstract: In an ink jet printer, a connecting member for connecting a belt to a carrier is separated from the carrier, and a vibration is absorbed by providing a fixed play at a place where the carrier and the connecting member are attached. Let it work. The vibration of the carrier is suppressed to suppress the deterioration of the printing quality. SOLUTION: The carrier 2 and the belt are connected via a connecting member 6 separate from the carrier 2. The connecting tool 6 has a belt mounting portion 61 and a projecting portion 66, and the projecting portion 66 is inserted into the hole 24 on the carrier side so as to be displaceable in the front-rear direction. A play space is formed between the protrusion 66 and the wall of the hole 24. Cushion material 7 having elasticity between flange-shaped surface 68 of belt mounting portion 61 and opening peripheral portion 26 of hole 24.
Intervene.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an ink jet printer.

[0002]

[Prior art]

 FIG. 13 is a schematic plan view for explaining a connection structure between a belt 1 and a carrier 2 employed in a conventional ink jet printer, and FIG. 14 is a schematic plan view of the connection structure for explaining a conventional problem. It is.

In this ink-jet printer, an endless timing belt having meshing teeth is used as the belt 1, and the belt 1 is fixed to a rotating shaft of a driving motor 3 which is a stepping motor. Is wound around a timing pulley 31 and a timing pulley (not shown) on the driven side, and reciprocates in a horizontal direction at a fixed position. On the other hand, a print head is mounted on the carrier 2. Further, a pair of left and right sliding portions 21 and 21 provided at a lower portion of the carrier 2 are slidably fitted to a horizontally arranged guide shaft 4, and the sliding portions 21 and 21 are connected to each other. The sliding movement of the guide shaft 4 guides the reciprocation of the carrier 2 indicated by the arrow a. Further, the carrier 2 and a predetermined portion of the belt 1 are connected via a connecting member 22. The connecting member 22 is formed of a synthetic resin integrally with the carrier 2, and is fixed to the belt 1 by inserting a predetermined portion of the belt 1 into an insertion groove provided in the connecting member 22 in a press-fit state. I have. Therefore, when the belt 1 is reciprocated by the drive motor 3, the carrier 2 connected to the belt 1 via the connecting member 22 follows the belt 1 and travels in the direction indicated by the arrow a.

On the other hand, JP-A-3-215068 and JP-A-4-45054 disclose a connection structure provided with a vibration damping member such as a rubber plate as a connection structure between a carriage and a belt corresponding to the carrier 2 described above. The document describes that a member for use is fixed to a carriage using mounting screws and a connecting member thereof is fixed to a belt.

In Japanese Utility Model Laid-Open Publication No. 4-58357, an elastic member is sandwiched between a belt holding plate screwed to a mounting bracket of a carriage and a belt as a connecting structure between a carriage and a belt. Things are listed.

[0006]

[Problems to be solved by the invention]

 By the way, in the conventional ink jet printer described with reference to FIG. 13, the ejection timing of the ink from the print head (not shown) mounted on the carrier 2 is controlled by the drive pulse waveform of the drive motor 3 which is a stepping motor. In this case, the uneven speed and vibration of the carrier 2 directly affect the quality of printing. Further, the uneven speed and vibration of the carrier 2 are caused by the vibration of the drive motor 1 and other parts transmitted to the carrier 2 via the belt 1. Then, even when speed unevenness or vibration occurs in the carrier, the ink ejection timing from the print head is controlled by the drive pulse waveform to the drive motor and performed as set. For this reason, when speed unevenness or vibration occurs in the carrier, gaps and overlapping unevenness occur in the dots, and these are expressed as shading of printing. If such a situation occurs constantly for every forward or backward movement of the carrier, a vertical stripe pattern H extending in the feed direction F of the paper P as shown in FIG. The quality will be degraded.

Further, when a print head maintenance operation is performed or a shock is applied to the printer set, the printing position is shifted due to the shock, and printing unevenness is caused, as shown in FIG. A strip-shaped horizontal stripe pattern L orthogonal to the feeding direction F of the paper P is generated, and the printing quality is deteriorated.

However, in the conventional ink jet printer described with reference to FIG. 13, a connecting member 22 formed of a synthetic resin integrally with the carrier 2 is fixed to a predetermined portion of the belt 1. Since the belt 1 is fixed by being inserted into the insertion hole portion provided in the connecting tool 22 in a press-fit state, the vibration of the belt 1 is easily transmitted to the carrier 2 directly through the connecting tool 22. There was a problem that the printing quality was likely to deteriorate. When the belt 1 is deviated forward as indicated by an arrow b as shown in FIG. 14, when the carrier 2 is pulled by the belt 1 in a rightward direction a1, for example, it joins the carrier 2. Force f is the direction of the resultant force of rightward force f1 and forwardward force F2. For this reason, there is a problem that the sliding portions 21 and 21 do not smoothly slide with respect to the guide shaft 4, and vibrations due to the sliding are generated in the carrier 2 and printing quality is deteriorated. A similar problem occurs when the carrier 2 runs while being pulled by the belt 1 in the left direction a2.

On the other hand, a vibration damping member is used as described in the above-mentioned Japanese Patent Application Laid-Open No. Hei 3-215068 and Japanese Utility Model Application Laid-Open No. 4-45054, or described in Japanese Utility Model Application Laid-Open No. 4-58357. According to the method using an elastic member as described above, since the vibration damping member and the elastic member partially exert the function of absorbing the vibration of the belt, the vibration transmitted from the belt to the carriage is reduced to some extent. It is also considered.

However, in the connection structure described in JP-A-3-215068, Japanese Utility Model Application Laid-Open No. 4-45054, and Japanese Utility Model Application Laid-Open No. 4-58357, the above-described connection that connects the belt and the carriage is used. Since the members corresponding to the members 22 are fixed to the carriage so as not to move, vibrations that cannot be completely absorbed by the damping member and the elastic member are transmitted to the carriage, and the carriage vibrates integrally with the belt. . Therefore, it was not sufficient to suppress a decrease in print quality due to carriage vibration.

[0011] The present invention has been made under the above-described circumstances. By dividing the connecting member from the carrier and providing a certain play at the mounting portion of both, the above-described vibration damping member and elastic member are used. To provide an ink jet printer capable of exhibiting an excellent vibration absorbing effect that cannot be exhibited, and thereby effectively suppressing the deterioration of printing quality due to uneven carrier speed and vibration. With the goal.

[0012]

[Means for Solving the Problems]

 The present invention is directed to an ink jet printer including a carrier on which a print head is mounted, a belt connected to the carrier to make the carrier follow, and a drive motor to make the belt reciprocate. I have. In such an ink jet printer, it is desirable that the carrier has a sliding portion which is fitted to the guide shaft in a sliding manner. Further, the drive motor may be a stepping motor, and the timing of ejecting ink from the print head may be controlled by a drive pulse waveform of the stepping motor.

[0013] In the present invention, the carrier and the belt are connected to each other through a connecting member separate from the carrier. The displacement in all directions is absorbed. As described above, if the displacement in all directions around the axis in the front-rear direction and the front-rear direction of the connector is absorbed at the attachment point between the carrier and the connector, the above-described vibration damping member or An excellent vibration absorbing action, which cannot be exhibited by the elastic member, is exhibited.

[0014] In order to absorb the omnidirectional displacement around the axis in the front-rear direction and the front-rear direction of the connecting device at the mounting location, the connecting device is provided at the mounting location with the front and rear directions of the connecting device and It is desirable to provide play for absorbing displacement in all directions around the longitudinal axis. Specifically, the connecting tool has a belt mounting portion fixed to the belt and a protruding portion connected to the belt mounting portion, and the protruding portion is provided on the carrier side of the mounting location. It is possible to adopt a configuration in which the protrusion is inserted into the hole so as to be displaceable in the front-rear direction, and a play space for the protrusion is formed between the protrusion and the wall surface of the hole. . With this configuration, the front-to-rear vibration of the belt is absorbed by the displacement of the projecting portion of the connecting member in the front-rear direction with respect to the hole on the carrier side, and the vertical vibration of the belt is also absorbed. The vibration of the belt or belt at the start or stop of travel is absorbed by the displacement of the protrusion in the play space of the protrusion.

[0015] In the present invention, the belt is a timing belt provided with meshing teeth, and the connecting device has a belt mounting portion to be fixed to the belt, and the belt mounting portion is the belt mounting portion. It is desirable that the belt has an insertion groove portion inserted in a non-press-fitted state, and engagement teeth meshing with the above-mentioned engagement teeth of the belt inserted in the insertion groove portion. In this case, since the belt is not pressed into the insertion groove of the belt mounting portion of the connecting member, the vibration of the belt is not easily transmitted to the connecting member. Nevertheless, the belt is less likely to fall out of the insertion groove due to the meshing teeth meshing with the engaging teeth. This effect is more remarkably exhibited by the curved insertion groove.

In the present invention, the belt mounting portion has a flange-shaped surface projecting around the projecting portion, and a cushion material having elasticity between the flange-shaped surface and the opening peripheral portion of the hole. In this case, it is desirable that a pressing force directed toward the carrier be applied to the connecting member by the belt. Further, it is desirable that the cushion material is pressed against the opening edge of the hole through the flange-shaped surface.

[0017] According to this configuration, since the side pressure due to the tension of the belt is constantly applied to the carrier, the posture of the carrier does not easily change in the front-rear direction, and the posture is stabilized. As a result, the carrier can run stably while maintaining a certain posture, which helps to prevent the printing quality from deteriorating due to uneven speed and vibration of the carrier.

In the present invention, it is preferable that a projection and a concave groove into which the projection is loosely fitted are formed separately to the projection and the hole. With this configuration, it is possible to prevent the connector from rotating more freely than necessary with respect to the carrier. For this reason, it is possible to prevent a situation in which an impact is applied to the carrier due to a recoil of the return operation after the coupling tool has idlely rotated more than necessary.

The function exhibited by the present invention will be apparent from the following description of embodiments.

[0020]

[Embodiment of the invention]

 FIG. 1 is a schematic partial front view showing an embodiment of the ink jet printer of the present invention, FIG. 2 is a front view showing a coupling structure between a connecting member 6 and a belt 1, and FIG. FIG. 4 is a schematic vertical sectional side view of a mounting portion between the carrier 2 and the connecting member 6, and FIG. 5 is a schematic vertical sectional front view of a mounting portion between the carrier 2 and the connecting member 6. is there.

In FIG. 1, a drive motor 3, which is a stepping motor, is mounted on a chassis 5, and a drive-side timing pulley 31 fixed to a rotating shaft of the drive motor 3 is driven by a driven pulley (not shown). An endless timing belt 1 is wound around the timing pulley. Therefore, when the drive motor 3 is driven to rotate in the forward and reverse directions, the rotation is converted into the horizontal reciprocation of the belt 1 via the timing pulley 31. A pair of left and right sliding portions 21 and 21 provided at the lower portion of the carrier 2 are slidably fitted on a horizontally arranged guide shaft 4, and the sliding portions 21 and 21 are used as guides. By sliding the shaft 4, the reciprocation of the carrier 2 is guided. Further, the carrier 2 and a predetermined portion of the belt 1 are connected via a connecting tool 6.

The connecting tool 6 is formed separately from the carrier 2. That is, as shown in FIG. 3, the connecting tool 6 in the illustrated example has a belt mounting portion 61 and a rod-shaped protrusion 66 connected to the belt mounting portion 61.

As shown in FIG. 2, the belt mounting portion 61 has an insertion groove 64 curved in an arc shape formed by a lower belt receiving portion 62 and an upper belt pressing portion 63. The holding portion 63 is provided with engaging teeth 65. In the belt mounting portion 61, a predetermined portion of the belt 1 is inserted into the insertion groove portion 64, and the meshing teeth 12 of the belt 1 mesh with the engaging teeth 65 of the belt pressing portion 63. The groove width of the insertion groove portion 64 is determined so that the belt 1 can be inserted in a non-press-fit state. As described above, when the belt 1 is inserted into the insertion groove portion 64 in a non-press-fit state, and the meshing teeth 12 of the belt 1 are meshed with the engaging teeth 65 of the belt pressing portion 63, the belt 1 At the same time, the belt 1 is prevented from falling off due to a change in thickness, and at the same time, the vibration of the belt 1 is less likely to be transmitted to the connector 6.

On the other hand, as shown in FIG. 3, a boss 23 is provided facing forward on the carrier 2 side. As shown in FIGS. 4 and 5, the protrusion 66 of the connecting member 6 is inserted into the hole 24 of the boss 23 so as to be displaceable in the front-rear direction. A play space S of the protruding part is formed between the wall and the wall of S.24. With this configuration, at the attachment point between the carrier 2 and the connecting member 6, the displacement of the connecting member 6 in all directions around the axis in the front-rear direction and the front-rear direction can be absorbed.

As shown in FIGS. 3 to 5, a rib-shaped projection 67 provided on the upper part of the protrusion 66 is loosely fitted into the concave groove 25 provided on the upper part of the hole 24. For this reason, it is possible to suppress the connecting tool 6 from rotating more freely than necessary with respect to the carrier 2, and as a result, the reaction of the return operation after the connecting tool 6 rotates more than necessary from play is suppressed. A situation in which a shock is applied to the carrier 2 is prevented.

The belt mounting portion 61 has a flange-shaped surface 68 projecting around the protrusion 66, and a cushion material having elasticity between the flange-shaped surface 68 and the opening peripheral portion 26 of the hole 24. 7 are interposed. For this cushion member 7, for example, a ring-shaped rubber plate having elasticity can be suitably used.

According to the above-described ink jet printer, displacements in the front-rear direction and all directions around the axis in the front-rear direction of the connecting member 6 are absorbed at the place where the carrier 2 and the connecting member 6 are attached. Therefore, even if the vibration of the drive motor 3 is transmitted to the connecting member 6 via the belt 1 and the connecting member 6 vibrates, the situation where the carrier 2 vibrates integrally with the belt 1 does not occur. Therefore, even when a stepping motor is used as the drive motor 3 and the timing of ejecting ink from the print head is controlled by the drive pulse waveform of the stepping motor, the speed of the carrier 2 is controlled. It is unlikely that the printing quality will be degraded due to unevenness or vibration. A case where this effect is exerted will be specifically described with reference to FIG.

FIG. 6 is an operation explanatory view showing in principle the ink jet printer described with reference to FIGS. As shown in the figure, when the belt 1 is deflected forward as indicated by an arrow b, when the carrier 2 is pulled by the belt 1 in the right direction a1, for example, the carrier 2 is directed to the right. Only the force f is applied, so that the sliding portions 21 and 21 slide smoothly with respect to the guide shaft 4, so that uneven speed and vibration due to sliding hardly occur in the carrier 2. Therefore, the situation that the printing quality is deteriorated is unlikely to occur. The same applies when the carrier 2 runs while being pulled by the belt 1 in the left direction a2.

FIG. 7 is an explanatory view showing, in principle, a case where the function of the cushion material 7 is effectively exerted. In this case, a pressing force A directed toward the carrier 2 is applied to the connecting member 6 by the tension of the belt 1. Therefore, the cushion member 7 is pressed against the opening peripheral edge 26 of the hole 24 of the boss 23 via the flange-shaped surface 68. With such a configuration, the lateral pressure due to the tension of the belt 1 is constantly applied to the carrier 2, so that the posture change of the carrier 2 in the front-rear direction is less likely to occur, and the posture is stabilized. Therefore, the carrier 2 keeps a constant posture and runs stably, which helps to prevent the printing quality from deteriorating due to uneven speed and vibration of the carrier 2.

In this embodiment, as shown in FIG. 4, a protruding piece 69 protrudes upward from the protruding portion 66 of the connector 6. A hole 27 is provided on the carrier 2 side, and a flanged stepped screw 8 is screwed into the hole 27. The flange 81 of the stepped screw 8 is opposed to the protruding piece 69. With this configuration, the protruding piece 69 hits the flange 81 when the protruding portion 66 of the connecting tool 6 is unnecessarily pulled out from the hole 24. For this reason, it is possible to prevent the connecting tool 6 from dropping out of the hole 24 or interfering with a chassis (not shown) provided on the front side of the hole 24.

FIG. 8 shows an example in which the hole 24 is formed in a square shape, and the projecting portion 66 of the connecting tool 6 is also formed in a square shape. Also in this combination, the connecting tool 6 has a belt mounting portion 61 fixed to a belt (not shown) and a projecting portion 66 connected to the belt mounting portion 61, and the projecting portion 66 is connected to the carrier side. The hole 24 is provided so as to be displaceable in the front-rear direction, and a play space for the protrusion is formed between the protrusion 66 and the wall surface of the hole 24. I have. Further, a protrusion 67 is provided on the protruding portion 66, and a concave groove 25 into which the protrusion 67 is loosely fitted is formed in the hole. Therefore, the same operation as in the case of the ink jet printer described with reference to FIGS.

Next, the operation of the ink jet printer according to the present invention and the conventional ink jet printer described with reference to FIGS. 13 and 14 will be described in comparison.

FIG. 9 is a graph (chart) showing the velocity displacement characteristics of the carrier of the ink jet printer according to the present invention, and FIG. 10 is a graph (chart) showing the velocity displacement characteristics of the carrier of the conventional ink jet printer. In these graphs, the horizontal axis indicates time, and the vertical axis indicates speed (15 ips = 0.756v). In the graphs, Z1 is the carrier acceleration range, Z2 is the constant carrier speed range, and Z3 is the carrier deceleration. Represents the area. Furthermore, the amplitudes above and below the characteristic curve indicate the width of the speed change, and the larger the amplitude, the more the carrier vibrates.

Comparing FIG. 9 with FIG. 10, the amplitude at the time when the acceleration of the carriers indicated by reference numerals A and B ′ is started, the acceleration of the carrier indicated by the reference numerals B and B ′ is completed, and the low speed region The amplitude of the carrier is smaller in the case of the present invention than in the case of the conventional example, regardless of the amplitude at the time of shifting to the period and the amplitude at the end of the low-speed region indicated by the symbols c and c. Of these, the vibration at the start of acceleration causes noise and is generated each time the carrier reversely moves. Further, the vibration at the end of the acceleration is generated by the so-called flapping of the carrier at the time of running up, and tends to cause uneven printing in the vertical direction. Furthermore, the vibration at the end of the low speed range is generated by the so-called unevenness of the carrier in the constant speed range, and is mainly caused by resonance by the drive motor and the belt. At any of the above points, it can be seen that in the ink jet printer of the present invention, the carrier is less likely to vibrate than in the conventional example, and as a result, the deterioration of the print quality is suppressed.

FIG. 11 is a graph (table) showing the horizontal vibration characteristics of the carrier of the inkjet printer according to the present invention, and FIG. 12 is a graph showing the horizontal vibration characteristics of the carrier of the conventional inkjet printer. (Chart). In these graphs, the horizontal axis represents time, and the vertical axis represents acceleration. The amplitudes above and below the characteristic curve indicate the width of the acceleration change, and the greater the amplitude, the more the carrier vibrates. Comparing FIG. 11 with FIG. 12, the vibration width of the carrier in the low-speed printing region is 0.46 V in the case of the present invention, whereas it is 1.04 V in the conventional example. From this, it can be seen that in the present invention, the vibration width is reduced by about 50% as compared with the conventional example. The noise level was 40.6 dbA in the case of the present invention, whereas it was 45.2 dbA in the conventional example. From this, it can be seen that the noise level of the present invention was reduced by about -5.4 dbA compared to the conventional example.

[0036]

[Effect of the invention]

 According to the present invention, an excellent vibration absorbing effect, which cannot be exerted by a vibration damping member or an elastic member as described in the gazette described at the beginning, is exhibited, and the printing quality due to the vibration of the carrier is improved. The decrease is effectively suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic partial front view showing an embodiment of an ink jet printer of the present invention.

FIG. 2 is a front view showing a coupling structure between a coupling tool and a belt.

FIG. 3 is a schematic exploded perspective view for explaining a mounting structure between a carrier and a coupling tool.

FIG. 4 is a schematic vertical sectional side view of a mounting portion between a carrier and a coupling tool.

FIG. 5 is a schematic longitudinal sectional front view of a mounting portion between a carrier and a coupling tool.

FIG. 6 is an operation explanatory view showing an ink jet printer in principle.

FIG. 7 is an explanatory view showing, in principle, a case where the action of the cushion material is effectively exerted.

FIG. 8 is a schematic exploded perspective view showing a modified example of the hole and the connecting member 6.

FIG. 9 is a graph showing a velocity displacement characteristic of a carrier of the ink jet printer according to the present invention.

FIG. 10 is a graph (chart) showing a velocity displacement characteristic of a carrier of a conventional inkjet printer.

FIG. 11 is a graph showing a vibration characteristic of the carrier of the inkjet printer according to the present invention in the left-right direction.

FIG. 12 is a graph (table) showing the vibration characteristics of a carrier of a conventional inkjet printer in the left-right direction.

FIG. 13 is a schematic plan view for explaining a connection structure between a belt and a carrier employed in a conventional inkjet printer.

FIG. 14 is a schematic plan view for explaining a conventional problem.

FIG. 15 is an explanatory diagram showing printing unevenness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Belt 2 Carrier 3 Drive motor 4 Guide shaft 6 Connector 7 Cushion material 12 Mesh teeth 21 Sliding part 24 Hole 25 Depressed groove 26 Periphery of opening of hole 61 Belt mounting part 64 Insertion groove 65 Engagement tooth 66 Projection 67 Projection 68 Flange surface S Play space

Claims (11)

[Utility model registration claims] 1. An ink jet printer comprising a carrier on which a print head is mounted, a belt connected to the carrier for following the carrier, and a drive motor for reciprocating the belt. And the belt are connected to each other via a connecting member separate from the carrier, and the mounting portion between the carrier and the connecting member absorbs displacement in all directions around an axis in the front-rear direction and the front-rear direction of the connecting member. An ink jet printer, characterized in that: 2. The ink jet printer according to claim 1, wherein the connecting portion is provided with play for absorbing displacement in all directions around the axis in the front-rear direction and the front-rear direction in the connecting portion. 3. The connecting device has a belt mounting portion fixed to the belt and a projecting portion connected to the belt mounting portion.
The protrusion is inserted into a hole provided on the carrier side of the mounting portion so as to be displaceable in the front-rear direction, and a play space of the protrusion is provided between the protrusion and a wall surface of the hole. The inkjet printer according to claim 2, wherein the ink jet printer is formed. 4. The belt is a timing belt provided with meshing teeth, wherein the connecting member has a belt mounting portion fixed to the belt, and the belt mounting portion is configured so that the belt is not press-fitted. The ink jet printer according to any one of claims 1 to 3, further comprising an insertion groove to be inserted, and engagement teeth meshing with the engagement teeth of the belt inserted into the insertion groove. 5. The insertion groove portion is curved.
The inkjet printer described in 1. 6. The belt mounting portion has a flange-shaped surface projecting around the protruding portion, and a cushion material having elasticity is interposed between the flange-shaped surface and the peripheral edge of the opening of the hole. An ink jet printer according to any one of claims 3 to 5, wherein: 7. The ink jet printer according to claim 6, wherein a pressing force toward the carrier is applied to the connecting member by the belt. 8. The ink jet printer according to claim 7, wherein said cushion material is pressed against an opening edge of said hole through said flange-shaped surface. 9. The ink jet printer according to claim 3, wherein a projection and a concave groove in which the projection is loosely fitted are formed by being distributed to the projection and the hole. 10. The ink jet printer according to claim 1, wherein the carrier has a sliding portion slidably fitted on the guide shaft. 11. The stepping motor according to claim 1, wherein the timing at which ink is ejected from the print head is controlled by a driving pulse waveform of the stepping motor.
The inkjet printer described in 1.