JP2003094678A - Ink supply unit for inkjet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and low-cost ink supply unit for an inkjet printer, which has excellent general-purpose properties. SOLUTION: This ink supply unit for the inkjet printer has an ink cartridge which is placed on the side of a printer body, a sub-tank which is coupled to a recording head mounted on a carriage, and a pump mechanism which is located near the ink cartridge so as to pressurize and supply ink to the sub- tank; and the pump mechanism comprises a reduction gear, which uses a drive motor and a worm gear, an eccentric cam, and a pump.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink supply device for an inkjet printer, and more particularly to an ink supply device for an inkjet printer using an ink cartridge that uses a flexible ink bag.

[0002]

2. Description of the Related Art As a conventional example, Japanese Patent Laid-Open No. 10-29699
Japanese Unexamined Patent Publication No. 2 (hereinafter referred to as Conventional Example 1) proposes a mechanism for selectively pressurizing an ink bag having a valve function with a cam to fill the ink. Further, in Japanese Patent No. 2,980,476 (hereinafter referred to as Conventional Example 2), a pressure pump (turbine pump) using an impeller is provided between a main tank and a tube.
An ink supply device provided with is proposed.

[0003]

However, according to the above-mentioned conventional example 1, a plurality of drive parts, transmission members, and pressurizing cams are required (as many as the number of cartridges), the apparatus becomes large and the cost is high. . Furthermore, since the ink bag is pressed from the side surface, it is impossible to discharge all the ink inside. Further, according to Conventional Example 2 described above, the pressurizing pump (turbine pump) for performing the discharge recovery process is provided directly below the main tank in which the ink cartridge is set. The point is that no pressure is generated unless the casing is filled with liquid. Also, when the device is shipped, all liquid should be drained and there should be no ink in the main tank. Furthermore, since the turbine pump does not have a closed space, the turbine must be rotated at high speed in order to generate a high pressure.
It is not suitable for pressurizing highly viscous liquids such as inkjet printers.

An object of the present invention is to solve these problems, and an object thereof is to provide an ink supply device for an ink jet printer which is excellent in versatility, small in size, and low in cost.

[0005]

In order to solve the above problems, an ink supply device for an ink jet printer according to the present invention comprises an ink cartridge mounted on the printer body side and a recording head mounted on a carriage. It has a sub tank connected thereto and a pump mechanism for pressurizing and supplying ink toward the sub tank in the vicinity of the ink cartridge, and the pump mechanism includes a speed reducer using a drive motor and a worm gear, an eccentric cam and a pump. It is characterized by being composed of. Therefore, the pump mechanism is configured as one unit, and even if the model is changed, it is possible to cope with the versatility, and it is easy to manage parts and products as a common unit.

Further, the speed reducer has a worm gear wheel whose rotation is transmitted from a worm gear fixed to a drive motor shaft, a second gear fixed coaxially with the worm gear wheel, and a third gear meshing with the second gear. Gears of the third
A fifth gear that meshes with the fourth gear and a fourth gear that is coaxially fixed to the second gear, and further includes a worm gear shaft center, a third gear shaft center, and a fifth gear shaft center. The centers of the shafts of the gears are arranged in the same plane. Therefore, the reduction ratio can be easily changed, and the holding member can be shared if the gear ratio is the same, and the size can be reduced.

Further, the center of the movable member of the pump and the holding member for holding the movable member is included in a part of the plane.

Further, the eccentric cam is fixed coaxially with the fifth gear, and the reciprocating operation of the pump is performed, whereby the durability can be increased.

Further, the speed reducer includes a worm gear fixed to the drive motor shaft, a worm gear wheel whose rotation is transmitted by the worm gear, a second worm gear fixed coaxially with the worm gear wheel, and a second worm gear. And a second worm gear wheel that meshes. Therefore, the parts can be shared, and the parts cost can be further reduced.

Further, the eccentric cam is fixed coaxially with the second worm gear wheel and the pump is operated, whereby durability can be increased.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An ink supply device for an ink jet printer of the present invention comprises an ink cartridge mounted on the printer body side, a sub tank connected to a recording head mounted on a carriage, and an ink cartridge near the ink cartridge. A pump mechanism for pressurizing and supplying the ink toward the sub tank, and the pump mechanism includes a drive motor, a speed reducer using a worm gear, an eccentric cam, and a pump.

[0012]

1 is a schematic diagram showing the construction of a color ink jet printer to which an ink supply device for an ink jet printer of the present invention is applied. In the figure, a sub-tank 12 is connected to a recording head (not shown) fixed to the carriage 11, and is housed in the carriage 11. The ink cartridge 13 is mounted on the printer body side. In the figure, two ink cartridges are separated on the left and right sides, but four ink cartridges may be mounted on one side.
A filter 14, a pump 15, a relay member 16 and the like are incorporated between the ink cartridge 13 and the sub tank 12, and basically communicate with the tube 17. The filter 14 is for filtering dust coming from the ink cartridge 13 side, and the relay member 16 is for relaying the tube 17 between the carriage 11 and the printer body side. In addition, although the tube 17 is connected in the same drawing, it is not particularly limited, and a tubeless structure may be used. The pump 15 has a function of forcibly pressurizing and filling the sub tank 12 with the ink of the ink cartridge 13. Therefore, the pump 15 is mounted on the printer body side near the ink cartridge 13. When the tube 17 is mounted at a position apart from the ink cartridge 13, the crawling of the tube 17 becomes complicated. Therefore, for example, when four ink cartridges are mounted on one side, the pump 14 is mounted in the vicinity thereof, for example, as shown in FIG. To be done.

FIG. 2 shows a general piston pump and its drive mechanism. In the figure, the drive motor 21 is a DC motor, and may be a stepping motor instead. A small DC motor has a rotation speed of 6000 to 9000 rotations, and it is used after being decelerated to 1/100 to 1/200. A general deceleration mechanism is shown in FIG. 2. If the unit from the drive motor to the pump body is considered as one unit and the unit is thinly configured, the arrangement as shown in FIG. 2 is obtained. As shown in the figure, the DC motor 21 and the pump 29 are inevitably oriented at right angles. DC motor 2 when four of them are lined up
A height of 1 is a problem. Also, the gear 22 used for deceleration
The number of ~ 27 is large, and it becomes 6 sheets. When the gears in FIG. 2 have the following number of teeth, the reduction ratio is as follows. Drive gear 2
2:10, 2nd gear 23:50, 3rd gear 24: 1
0, 4th gear 25:50, 5th gear 26:10,
6th gear 27: 50/10 sheets, 10/50 × 10/5
The reduction ratio is 0 × 10/50 = 1/125.

Therefore, the ink supply device according to the present invention is a mechanism that solves such a problem, reduces the number of gears, and allows a large reduction ratio.

FIG. 3 is a view showing the arrangement of the ink supply apparatus of the ink jet printer according to the first embodiment of the present invention. In the figure, (a) is a plan view and (b) is a front view. In the figure, a worm gear 40 and a first gear 32, a third gear 34 that meshes with a second gear 33 that is integrally formed with the first gear 32, and a third gear 34 that is coaxial with the third gear 34 are attached to the drive motor shaft of the DC motor 31. It is composed of a fourth gear 35 and a fifth gear 36 that meshes with the fourth gear 35. If the worm gear 40 is included, there are six configurations, but since the worm gear 40 has a large reduction ratio, it can be configured with the following number of teeth.

Worm gear 40: Number of threads 1, first gear 3
2:20, second gear 33:12, third gear 34: 3
With 6 sheets, 4th gear 35:12 sheets, and 5th gear 36:36 sheets, 1/20 × 12/36 × 12/36 = 1/12
The reduction ratio is 0. In the conventional example, the reduction gear ratio is almost unchanged even when the conventional gear has 50 teeth and 36 teeth. The DC motor 31 and the pump body 38 are both sideways. As shown in the plan view of FIG. 3A, the thickness of the unit is slightly increased. In FIG. 3B, when the central axes of the DC motor 31, the third gear 34, the fifth gear 36, the pump body 38, etc. are present in one plane and are arranged in a horizontal row as in the front view, The whole can be made small. Although FIG. 3 shows an example of a piston pump, a diaphragm pump can also obtain similar performance.
Further, a compression spring 39 is attached to the piston for constantly pressing it toward the eccentric cam 37 side. This makes it possible to easily adjust the components even if they are misaligned.

FIG. 4 is a schematic view showing the arrangement of an ink supply apparatus for an ink jet printer according to the second embodiment of the present invention. Also in the second embodiment shown in the figure, a worm gear is used for the drive motor shaft. The second worm gear 44 is fixed coaxially with the first gear 43, and the second gear 45 meshes with the second worm gear 44. The reduction ratio is the first and second worm gears 42 and 44: the number of threads 1, the first gear 43: 11 sheets, the second
Gear 45: 11 sheets, 1/11 × 1/11 = 1/12
It becomes 1. Even if the number of teeth of the first gear 43 and the second gear 45 is 11, a reduction ratio of 1/121 can be obtained. Thus, a large reduction ratio can be obtained with a small number of parts.

FIG. 5 is a characteristic diagram showing the relationship between the ink remaining amount of the ink cartridge and the negative pressure, and shows the change of the pressure at the supply port when the ink is discharged from the ink cartridge. The ink cartridge is assumed to have an ink bag structure. FIG. 6 is a characteristic diagram showing the relationship between the load torque of the drive motor and the drive current value. When the ink in the cartridge is used up, the load increases and the current value of the motor also increases.

Therefore, the relationship between the remaining amount of ink and the drive current is stored in advance, and as shown in FIG. 7, the drive current detection circuit 61 detects the drive current value, and the remaining ink amount-drive current value comparison circuit 62. The remaining ink amount can be obtained by comparing the previously stored relationship between the remaining ink amount and the drive current, and the remaining ink amount can be displayed on the remaining ink amount display portion 63. Also, at the ink end of the ink cartridge, the negative pressure rapidly increases when the ink runs out, so the current value at that time (abnormally increased) and the time to replenish the ink (replenishment is completed by turning on the full tank sensor in the sub tank) When any of them shows an abnormal value, specifically, when the drive current value (A) detected by the drive current detection circuit 61 of FIG. 7 becomes larger than the MAX current value (A ′), or When the time (B) measured by the timer exceeds the MAX replenishment time (B '), the end is set.

It is needless to say that the present invention is not limited to the above embodiments, and various modifications and substitutions can be made within the scope of the claims.

[0021]

As described above, the ink supply device for an ink jet printer of the present invention includes an ink cartridge mounted on the printer body side, a sub-tank connected to a recording head mounted on a carriage, and an ink. A pump mechanism for pressurizing and supplying ink toward the sub-tank is provided near the cartridge, and the pump mechanism includes a drive motor, a speed reducer using a worm gear, an eccentric cam, and a pump. There is. Therefore, the pump mechanism is configured as one unit, and even if the model is changed, it is possible to cope with the versatility, and it is easy to manage parts and products as a common unit.

The speed reducer has a worm gear wheel whose rotation is transmitted from a worm gear fixed to the drive motor shaft, a second gear fixed coaxially with the worm gear wheel, and a third gear meshing with the second gear. Gears of the third
A fifth gear that meshes with the fourth gear and a fourth gear that is coaxially fixed to the second gear, and further includes a worm gear shaft center, a third gear shaft center, and a fifth gear shaft center. The centers of the shafts of the gears are arranged in the same plane. Therefore, the reduction ratio can be easily changed, and the holding member can be shared if the gear ratio is the same, and the size can be reduced.

Further, the center of the movable member of the pump and the holding member for holding the movable member is included in a part of the plane.

Further, durability can be increased by fixing the eccentric cam coaxially with the fifth gear so that the pump reciprocates.

Further, the reduction gear has a worm gear fixed to the drive motor shaft, a worm gear wheel whose rotation is transmitted by the worm gear, a second worm gear fixed coaxially with the worm gear wheel, and a second worm gear. And a second worm gear wheel that meshes. Therefore, the parts can be shared, and the parts cost can be further reduced.

Further, the eccentric cam is fixed coaxially with the second worm gear wheel and the pump is operated, whereby durability can be increased.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the configuration of a color inkjet printer to which an ink supply device for an inkjet printer of the present invention is applied.

FIG. 2 is a schematic diagram showing a general piston pump and its drive mechanism.

FIG. 3 is a diagram showing a configuration of an ink supply device of the inkjet printer according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing a configuration of an ink supply device of an inkjet printer according to a second embodiment of the present invention.

FIG. 5 is a characteristic diagram showing the relationship between the ink remaining amount of the ink cartridge and the negative pressure.

FIG. 6 is a characteristic diagram showing a relationship between a load torque of a drive motor and a drive current value.

FIG. 7 is a block diagram showing a configuration of an ink remaining amount display circuit.

[Explanation of symbols]

31; DC motor, 32; first gear, 33; second gear, 34; third gear, 35; fourth gear, 36; fifth gear, 37; eccentric cam, 38; pump body , 39: compression spring, 40: worm gear.

Claims (6)

[Claims] 1. An ink cartridge mounted on the printer body side, a sub-tank connected to a recording head mounted on a carriage, and an ink in the vicinity of the ink cartridge under pressure toward the sub-tank. And a pump mechanism, the pump mechanism including a speed reducer using a drive motor and a worm gear, an eccentric cam, and a pump. 2. The decelerator includes a worm gear wheel whose rotation is transmitted from a worm gear fixed to a drive motor shaft, a second gear fixed coaxially with the worm gear wheel, and a second gear. A third gear that meshes,
A fourth gear fixed coaxially with the third gear, and a fifth gear meshing with the fourth gear, the center of the shaft of the worm gear and the shaft of the third gear. The heart of
The ink supply device for an inkjet printer according to claim 1, wherein the centers of the axes of the fifth gears are arranged in the same plane. 3. The ink supply device for an inkjet printer according to claim 1, wherein the movable member of the pump and the center of the holding member that holds the movable member are included in a part of the plane. 4. The eccentric cam is fixed coaxially with the fifth gear to allow the pump to reciprocate.
4. The ink supply device for an inkjet printer according to any one of 3 to 3. 5. The decelerator includes a worm gear fixed to a drive motor shaft, a worm gear wheel whose rotation is transmitted by the worm gear, a second worm gear fixed coaxially with the worm gear wheel, and a second worm gear. Two
2. The ink supply device for an inkjet printer according to claim 1, further comprising a second worm gear wheel that meshes with the worm gear of FIG. 6. The ink supply device for an ink jet printer according to claim 5, wherein the eccentric cam is fixed coaxially with the second worm gear wheel to operate a pump.