JP2009078415A - Liquid ejector - Google Patents

Abstract

In a configuration for reducing or preventing vibrations by moving two carriages in opposite directions, the load of a motor that drives the two carriages is made uniform, thereby obtaining good recording quality.
A first carriage 1A and a second carriage 1B are configured to move in opposite directions, and when the distance La between the curve reversal portion Ra of the first ink tube 3A and the first carriage 1A is the shortest, the second ink The distance Lb between the curve reversal part Rb of the tube 3B and the second carriage 1B is the longest, and when the distance La is the longest, the distance Lb is the shortest. Therefore, the resultant force of the frictional force generated between the first carriage 1A and the first guide shaft 4A and the frictional force generated between the second carriage 1B and the first guide shaft 4B is generated at the carriage position. Regardless, it is constant, and the motor load is made uniform, so that good recording quality can be obtained.
[Selection] Figure 1

Description

  The present invention relates to a liquid ejecting apparatus that ejects liquid onto a medium to be ejected. Here, the liquid ejecting apparatus uses an ink jet recording head, and is not limited to a recording apparatus such as a printer, a copying machine, and a facsimile machine that discharges ink from the recording head to perform recording on a recording medium. And a device that ejects a liquid corresponding to the application from a liquid ejecting head corresponding to the ink jet recording head to an ejected medium corresponding to a recording medium, and adheres the liquid to the ejected medium. .

  In addition to the recording head, as a liquid ejecting head, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, and an electrode material (conductive paste) used for forming an electrode such as an organic EL display or a surface emitting display (FED) Examples thereof include an ejection head, a bioorganic matter ejection head used for biochip production, and a sample ejection head as a precision pipette.

  Hereinafter, an ink jet printer as an example of a recording apparatus and a liquid ejecting apparatus will be described as an example. Ink jet printers, particularly serial type ink jet printers, include a recording head for ejecting ink on a recording sheet. The carriage is guided by a guide shaft extending in the main scanning direction, and fixed to, for example, a part of an endless belt, and is configured to reciprocate in the main scanning direction by being pulled by the endless belt. .

  However, such a serial type ink jet printer has such a characteristic that vibration (swing) is generated with the reciprocation of the carriage, and this vibration may reduce the recording quality. Therefore, conventionally, a technique has been proposed in which a heavy object (dummy carriage) that moves in the direction opposite to the moving direction of the carriage is provided to cancel vibrations associated with the reciprocating movement of the carriage (for example, Patent Documents 1 to 4).

  Therefore, for example, if two carriages equipped with recording heads are provided and each carriage is moved in the opposite direction, vibration associated with the reciprocating operation of the carriage can be reduced or prevented, and good recording quality can be obtained. In addition, the throughput can be improved by increasing the number of ink ejection nozzles.

  By the way, there are two types of carriages (so-called on-carriage type) in which an ink cartridge is mounted, and types that do not have an ink cartridge (so-called off-carriage type). In an off-carriage type ink jet printer in which an ink cartridge is not mounted on a carriage, an ink cartridge provided independently from the carriage and an ink jet recording head mounted on the carriage are separated by a flexible member (for example, an ink tube). Connected.

Here, since the flexible member has a self-recovery habit of trying to return straight, the restoring force due to the self-reset habit acts on the carriage, thereby adversely affecting the operation of the carriage and reducing the ink landing accuracy. The recording quality may be reduced.
Therefore, in order to solve such a problem, Patent Document 5 discloses that an ink tube is arranged on one side of the carriage movement path and a flexible flat cable is arranged on the other side, and both self-recovery habits are provided. An ink jet recording apparatus is disclosed which is configured to obtain a balance of forces applied to the carriage by being configured so that the restoring forces due to each other are weakened.
JP 2001-138499 A JP 2001-328305 A JP 2002-219796 A JP 2004-34647 A JP 2002-321351 A

  Incidentally, the restoring force due to the self-returning behavior of the flexible member specifically affects the frictional force between the guide shaft that guides the carriage and the bearing member in the carriage. That is, when the restoring force increases, the frictional force between the guide shaft and the bearing member increases, and when the restoring force decreases, the frictional force between the guide shaft and the bearing member decreases.

  Since the restoring force due to the self-recovery behavior of the flexible member acting on the carriage changes depending on the position of the carriage, the frictional force also changes depending on the position of the carriage. For this reason, the load applied to the motor for driving the carriage varies depending on the position of the carriage, resulting in a technical problem that the carriage speed varies and the recording quality deteriorates.

  In particular, in the configuration in which two carriages are provided and the two carriages are driven by one motor, the load on the motors increases, and thus the above technical problem becomes a particular problem. And about the said technical subject, it was not considered at all in the prior art as shown in patent documents 1-5.

  Accordingly, the present invention has been made in view of such a situation, and an object of the present invention is to provide a motor for driving two carriages in a configuration in which vibrations are reduced or prevented by moving the two carriages in opposite directions. The purpose is to make the load uniform and to obtain good recording quality.

  In order to solve the above-described problem, a liquid ejecting apparatus according to a first aspect of the present invention includes an endless belt that is entrained between at least two pulleys and driven by the power of a motor, and ejects liquid onto an ejected medium. A first carriage fixed to a part of the endless belt, a first guide member for guiding the first carriage in a moving direction thereof, and a liquid storage section independent of the first carriage. And a liquid tube having flexibility for connecting the liquid ejecting head of the first carriage, after extending from the first carriage in the moving direction of one of the first carriages, A second carriage that includes a first liquid tube that reverses its curvature and extends in the opposite direction, and a liquid ejecting head that ejects liquid onto the ejected medium, and is fixed to a part of the endless belt. The second guide member for guiding the second carriage in the moving direction thereof, and a flexible liquid tube for connecting the liquid reservoir and the liquid jet head of the second carriage, A second liquid tube extending from the two carriages in the moving direction of one of the second carriages and then reversing the curve and extending in the opposite direction, and the second carriage is connected to the second carriage When one carriage is positioned at one end of the reciprocating region, the endless belt is disposed at the other end and is operated in the direction opposite to the direction of movement of the first carriage. The extending direction of the second liquid tube is the same as the extending direction of the first liquid tube.

  According to this aspect, since the second carriage operates in the direction opposite to the operation direction of the first carriage, the second carriage is balanced by the first carriage and the second carriage, and the vibration accompanying the movement operation of the carriage is reduced. Is prevented.

  Since the extending direction of the second liquid tube is the same as the extending direction of the first liquid tube, when the distance between the curved reversal portion of the first liquid tube and the first carriage is the longest, the second liquid tube The distance between the curved reversal part of the liquid tube and the second carriage is the shortest. Further, when the distance between the curve reversal part of the first liquid tube and the first carriage is the shortest, the distance between the curve reversal part of the second liquid tube and the second carriage becomes the longest.

  That is, when the restoring force that the first liquid tube exerts on the first carriage is the largest, the restoring force that the second liquid tube exerts on the second carriage is the smallest, and the restoring force that the first liquid tube exerts on the first carriage is the most. When it is small, the restoring force exerted on the second carriage by the second liquid tube is the largest.

  As a result, the load for driving the first carriage and the load for driving the second carriage are balanced, and the motor for driving the first carriage and the second carriage is positioned at the positions of the first carriage and the second carriage. Regardless, an almost constant load is applied. Therefore, the speed variation of the first carriage and the second carriage is reduced or prevented, and good liquid ejection quality can be obtained.

  Hereinafter, an ink jet printer (hereinafter referred to as “printer”) 100 as an embodiment of a liquid ejecting apparatus according to the invention will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a plan view of the principal part of the printer 100, and FIG. 2 is a diagram showing the relationship between the frictional force generated between the carriage (bearing) and the guide shaft and the carriage position (position of the carriage 1A).

  In FIG. 1, a printer 100 includes a side frame right 8A and a side frame left 8B that are parallel to the conveyance direction of a cut sheet P as an example of an ejected medium, a frame 7A that is orthogonal thereto, and a frame that is provided on the downstream side. 7B, and the base of the apparatus is constituted by these frames. In the following description, a direction (left-right direction in FIG. 1) orthogonal to the conveyance direction (up-down direction in FIG. 1) of the cut sheet P is referred to as “main scanning direction”.

  Between the side frame right 8 and the side frame left 8B, a first guide shaft 4A as a “first guide member” and a second guide shaft 4B as a “second guide member” are respectively in the main scanning direction. The first carriage 1A is guided by the first guide shaft 4A, and the second carriage 1B is guided by the second guide shaft 4B.

  The first carriage 1A includes a first recording head 2A as a liquid ejecting head, and ejects ink as an example of liquid from the first recording head 2A toward the cut sheet P. Further, bearings 5 and 5 are provided on both sides of the first carriage 1A, and the first carriage 1A is guided to the first guide shaft 4A via the bearings 5 and 5. Similarly, the second carriage 1B includes a second recording head 2B and bearings 5 and 5.

  Between the first carriage 1A and the second carriage 1B, a driving pulley 10 driven by a motor 9 and a driven pulley 11 driven to rotate are disposed at a predetermined interval in the main scanning direction. An endless belt 12 is wound around the driven pulley 11.

  The first carriage 1A is fixed to the upstream portion of the endless belt 12, and the second carriage 1B is fixed to the downstream portion of the endless belt 12. Therefore, the first carriage 1A and the second carriage 1B are rotated by the motor 9. Operate in opposite directions.

  When the first carriage 1A is positioned at one end of the reciprocating region, for example, at the end of one digit as shown by the solid line in FIG. 1, the second carriage 1B is at the opposite end, As shown by the solid line in FIG. 1, it is fixed so as to be located at the end of the 80th digit side.

  Accordingly, when the first carriage 1A moves to the end of the 80th digit side as indicated by the imaginary line and reference numeral 1A 'in FIG. 1, the second carriage 1B moves one digit side as indicated by the imaginary line and reference numeral 1B' in FIG. It will move to the end of the. In this way, while the two carriages move in the opposite directions, ink is ejected from the recording heads mounted on the two carriages, so that recording on the cut sheet P is executed with high throughput.

  Next, both the first carriage 1A and the second carriage 1B are so-called off-carriage types in which no ink cartridge is mounted. The “liquid storage” is provided on the apparatus main body side, more specifically, on the left side frame 8B on the 80-digit side. Ink is supplied to each recording head from the ink tank 13 as a “section”.

  The recording head 2A of the first carriage 1A and the ink tank 13 are connected by a first ink tube 3A that is a flexible liquid tube, and the recording head 2B and the ink tank 13 of the second carriage 1B are similarly configured. Connected by the second ink tube 3B.

  The first ink tube 3A extends from the side surface on the 1st digit side of the first carriage 1A toward the main scanning direction (1st digit side), and then reverses the curve to the reverse direction (80th digit side). It extends along 7A and is routed to enter the ink tank 13. The first ink tube 3A is fixed to the frame 7A by tube fixing members 6 and 6 provided on the frame 7A.

  Similarly to the first ink tube 3A, the second ink tube 3B extends from the side surface on the first digit side of the second carriage 1B toward the main scanning direction (one digit side), and then reverses the curve and reverses the direction. It extends along the frame 7 </ b> B toward (80 digit side) and is routed to enter the ink tank 13. The second ink tube 3B is fixed to the frame 7B by tube fixing members 6 and 6 provided on the frame 7B.

  In the printer 100 configured as described above, since the first carriage 1A and the second carriage 1B operate in opposite directions, the first carriage 1A is balanced by the first carriage 1A and the second carriage 1B. And vibration associated with the movement of the second carriage 1B is reduced or prevented. Accordingly, this prevents the recording quality from being deteriorated due to vibration caused by the carriage operation.

  Next, since the extending direction of the second ink tube 3B from the second carriage 1B is the same as the extending direction of the first ink tube 3A from the first carriage 1A, the curve of the first ink tube 3A is reversed. When the distance La between the portion Ra and the first carriage 1A is the shortest, the distance Lb between the curve reversal portion Rb of the second ink tube 3B and the second carriage 1B is the longest (the first carriage 1A and the second carriage indicated by solid lines). Carriage 1B).

  When the distance La between the curve reversal portion Ra of the first ink tube 3A and the first carriage 1A is the longest, the distance Lb between the curve reversal portion Rb of the second ink tube 3B and the second carriage 1B is the shortest (imaginary) A first carriage 1A and a second carriage 1B).

  Here, with respect to the first carriage 1A, when the distance La is shortened, the restoring force (indicated by reference numeral Fa) due to the self-recovery behavior of the first ink tube 1A acting on the first carriage 1A increases, and conversely the distance La As the length increases, the restoring force decreases.

  Similarly, for the second carriage 1B, when the distance Lb is shortened, the restoring force (indicated by the symbol Fb) acting on the second carriage 1B due to the self-recovery behavior of the second ink tube 1B increases, and conversely, the distance Lb becomes smaller. As the length increases, the restoring force decreases.

  Therefore, for each carriage, the frictional force between the guide shaft and the bearing varies depending on the position in the main scanning direction as shown in FIG. Specifically, the first carriage 1A has the largest frictional force when located on the 1st digit side, and the smallest frictional force when located on the 80th digit side. Similarly, the second carriage 1B has the largest frictional force when located on the 1st digit side and the smallest frictional force when located on the 80th digit side.

  Here, if the frictional force of both is increased and decreased simultaneously, the load on the motor 9 that drives both carriages is extremely large at some time and small at other times. The carriage speed becomes non-uniform according to the carriage position, and there is a possibility that the recording quality is lowered.

  However, as described above, in the printer 100, as the distance La between the curve reversal portion Ra of the first ink tube 3A and the first carriage 1A becomes shorter, the curve reversal portion Rb of the second ink tube 3B and the second carriage 1B. The distance Lb becomes shorter as the distance Lb becomes longer and the distance La becomes longer.

  Therefore, the resultant force of the frictional force generated between the first carriage 1A and the first guide shaft 4A and the frictional force generated between the second carriage 1B and the first guide shaft 4B is shown in FIG. As shown, it is constant regardless of the position of the first carriage 1A and the second carriage 1B.

  Accordingly, a substantially constant load is applied to the motor 9, which is a common drive source for the first carriage 1A and the second carriage 1B, regardless of the positions of the first carriage 1A and the second carriage 1B. Variations in the speed of the second carriage 1B are reduced or prevented, and good recording quality can be obtained.

  When a flexible flat cable (hereinafter referred to as “FFC”) for transmitting an electrical signal to the recording head mounted on each carriage is attached to each ink tube, the self-recovery behavior of FFC A restoring force acts on each carriage, and a frictional force between each carriage and the guide shaft increases. However, even in such a case, as described above, the frictional force is constant regardless of the carriage position, so that good recording quality can be obtained.

FIG. 2 is a plan view of a main part of the printer according to the invention. The figure which shows the relationship between the frictional force which arises between a carriage and a guide shaft, and a carriage position.

Explanation of symbols

1A first carriage, 1B second carriage, 2A, 2B recording head, 3A first ink tube, 3B second ink tube, 4A first guide shaft, 4B second guide shaft, 5 bearing, 6 tube fixing member, 7A, 7B frame, 8A side frame right, 8B side frame left, 9 motor, 10 drive pulley, 11 driven pulley, 12 endless belt, 13 ink tank, 100 inkjet printer

Claims (1)

An endless belt that is entrained between at least two pulleys and driven by the power of the motor;
A first carriage that includes a liquid ejecting head that ejects liquid onto a medium to be ejected, and is fixed to a part of the endless belt;
A first guide member for guiding the first carriage in the moving direction;
A liquid tube having flexibility for connecting a liquid storage section independent of the first carriage and a liquid ejecting head of the first carriage, wherein either one of the first carriage and the first carriage is provided. A first liquid tube that extends in the direction of movement and then inverts and extends in the opposite direction;
A second carriage that includes a liquid ejecting head that ejects liquid onto the ejection target medium, and is fixed to a part of the endless belt;
A second guide member for guiding the second carriage in the moving direction;
A flexible liquid tube that connects the liquid storage section and the liquid ejection head of the second carriage, and extends from the second carriage toward the moving direction of one of the second carriages. A second liquid tube that reverses the curve and extends in the opposite direction after being removed,
The second carriage is arranged at the other end when the first carriage is located at one end of the reciprocating region, and is opposite to the operation direction of the first carriage. Fixed to the endless belt to operate,
The liquid ejecting apparatus according to claim 1, wherein an extending direction of the second liquid tube is the same as an extending direction of the first liquid tube.

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