Patent Application
20090009568
1. Field of the Invention
The present invention relates to a flow path connecting device for automatically interconnecting flow paths of liquids to communicate with each other or for separating the flow paths from each other, or to a recording apparatus for supplying inks from the outside of a carrier including the flow path connecting device.
2. Description of the Related Art
A recent printing apparatus for a business purpose is expected to reduce the number of replacing times and running costs, so that a large capacity is required of an ink tank that contains a printing ink.
An apparatus that performs printing by moving a carrier having a printing mechanism in a direction perpendicular to a printing sheet feeding direction generally mounts an ink tank on the carrier.
However, this method has disadvantages, for example, if size of the carrier or weight of the ink tank is increased the speed of the carrier will decrease, or the size of a carrier motor must be increased to compensate for the reduction in speed. To solve such a problem, the ink tank can be arranged separately from the carrier, and the carrier printing mechanism and the ink tank can be interconnected through a tube.
In such a tube connection method, the length of the tube needs to be set in anticipation of carrier movement. This method also has problems such as a detrimental influence of tube rigidity on the carrier movement, incursion of air into the ink from the outside of the tube, and evaporation of ink water to the outside of the tube, which makes it difficult to select a tube material.
As an example of a solution to the aforementioned problems, an ink supply mechanism is discussed in Japanese Patent Application Laid-Open No. 2002-113879. In this ink supply mechanism, a connection mechanism that divides an ink supply path is disposed between an apparatus main-body having a large-capacity ink tank and a moveable carrier having a printing mechanism. The connection mechanism at main-body side and the connection mechanism at a carrier-side are configured such that an ink flow path is formed to supply the ink to the carrier side when connected together, and leakage of the ink from each connection mechanism can be prevented when separated from each other.
However, in the case of the supply mechanism and the operation discussed in Japanese Patent Application Laid-Open No. 2002-113879, there is a possibility that when the connection mechanisms are separated from each other, the ink left in each connection mechanism will scatter and contaminate a printing sheet.
The present invention is directed to a mechanism for preventing or reduce the scattering of the ink from such a connection portion.
According to an aspect of the present invention, a flow path connecting device includes a first flow path having a first connector and configured to channel fluids, a second flow path having a second connector and configured to channel fluids, a moving unit operable to move at least one of the first and second connectors, to interconnect the first and second connectors so that the first and second flow paths are communicated with each other, and operable to move at least one of the first and second connectors to separate the first and second connectors from each other, and a control unit configured to control the moving unit, when the first and second connectors separate from each other, to set a relative speed of the first and second connectors to a first speed or less in a period from a start of the separation till a predetermined time expires, and set the relative speed to a second speed that is higher than the first speed after the predetermined time expires.
According to an exemplary embodiment of the present invention, scattering of fluids caused when the first connector of the first flow path and the second connector of the second flow path are separated from a connected state can be reduced.
Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.
Various exemplary embodiments, features, and aspects of the invention will now be described in detail with reference to the drawings.
The printing apparatus 1 includes a casing cover 901, a maintenance cover 902, a guide 903 for supporting a print sheet 906, and a discharge port 904 for discharging the print sheet 906 which is a printed recording medium. The print sheet 906 is discharged in an arrow direction A.
The printing apparatus 1 further includes a cover 907 for replacing an ink tank 101 that is replaceably installed in a casing to reserve a liquid. In a state that the cover 907 is open as illustrated in
A carrier 206 is supported to move reciprocally along a shaft 207 and a guide 205 in an arrow direction B. A motor 209 reciprocates the carrier 206 along the shaft 207 and the guide 205 in the arrow direction B via a belt 208. A maintenance mechanism 210 is configured to maintain a printing mechanism mounted on the carrier 206.
A main-body side supply mechanism 301 includes a mechanism of supplying inks as fluids or liquids to the carrier 206 from the outside. The main-body side supply mechanism 301 is supported by a shaft 302 and a guide 303 supported on the chassis 201 to move reciprocally in an arrow direction C perpendicular to the moving direction B of the carrier 206.
A pump 304 serves as a pressure reducing unit for generating negative pressure to form an ink flow. The negative pressure is connected through a tube 305 and a negative pressure connection unit 306 to the main-body side supply mechanism 301.
A supply port 307 is connected with the ink tank 101. By pushing-in the ink tank 101 toward the casing cover 901, the ink tank 101 is coupled with the supply port 307 so that no ink leakage will occur.
The supply port 307 is connected through a tube 308 and a negative pressure valve 309 to the main-body side supply mechanism 301. A sub-ink tank 310 serves as a liquid chamber on the carrier 206 side. Negative pressure valves 311 and 312 are attached to the sub-ink tank 310.
A rotation driving device 313 moves reciprocally the main-body side supply mechanism 301 in the arrow direction C and drives the pump 304. A driving direction of the pump 304 is not limited to a rotational direction of the rotation driving device 313, and the main-body side supply mechanism 301 side is configured to transmit driving force only in one direction by a one-way clutch (not shown).
A connection cam 316 is driven and rotated by the rotation driving device 313. A cam surface of the connection cam 316 abuts on a side face 301a of the main-body side supply mechanism 301, and rotates to move the main-body side supply mechanism 301 closer to the carrier 206. Then, the negative pressure valve 309 and a part of the negative pressure connection unit 306 are moved to a position where they abut on a backside 206a of the carrier 206. When a small-diameter part of the connection cam 316 rotates up to an initial position where the small-diameter part abuts on the side face 301a, the main-body side supply mechanism 301 is moved away from the carrier 206 under a spring force, and the negative pressure valve 309 and the negative pressure connection unit 306 are separated from the backside 206a of the carrier 206. The connection cam 316 and the spring constitute a moving unit. A disk 314 rotating integrally with the connection cam 316 includes a notch formed in a predetermined position. The notch is detected by a position sensor 315 to control a rotational angle phase of the connection cam 316.
The rotation driving device 313 and the position sensor 315 are connected to a control circuit 700 (
However, the negative pressure connection unit 306 does not include the spherical valve 402 and the spring 403 but includes only the cylinder 401 and the sealing member 404.
The pressure difference shows a relation, communication port 401a side pressure>sealing member 404 side pressure, and is determined by setting of the spring 403. When the pressure difference exceeds the retaining force of the spring 403, the spherical valve 402 moves away from the slope surface in the cylinder 401 so that the communication port 401a side is communicated with the sealing member 404 side.
When a sealing surface 404c of a rib 404b of the sealing member 404 abuts on a backside 206a of the carrier 206, the rib 404b deforms to provide an air-tight seal.
An inkjet printing mechanism 504 is provided with an array of minute nozzles and includes an energy generating element for generating discharge pressure corresponding to each nozzle. The energy generating element is controlled to discharge ink from the corresponding nozzle based on a control signal sent from the control circuit 700 via a wiring line (not shown).
The carrier 206 includes a negative pressure port 505, an ink supply port 506, and holes 507 and 508 for adjusting a position with positioning bosses 317 and 318 of the main-body side supply mechanism 301.
A negative pressure valve 509 controls a flow rate of an ink from a sub-tank 310 into an ink buffer chamber 510 of the inkjet printing mechanism 504 and is connected to the ink buffer chamber 510 through the communication port 511.
A configuration of the negative pressure valves 309, 311, 312, and 509 is similar to that of
Each of
When the inkjet printing mechanism 504 consumes the ink in the ink buffer chamber 510, pressure within the ink buffer chamber 510 becomes negative. When the negative pressure reaches a certain value, a spherical valve 509a of the negative pressure valve 509 compresses a spring 509b to make an opening, thereby supplying an ink from the sub-tank 310 into the ink buffer chamber 510.
When the ink of the sub-tank 310 is reduced to produce negative pressure therein, and the negative pressure reaches a certain value, a spherical valve 312a of the negative pressure valve 312 opens to cause an atmosphere to flow in. When flowing-in of the atmosphere reaches a certain extent, a spring 312b of the negative pressure valve 312 closes the spherical valve 312a. The negative pressure is maintained in the sub-tank 310 and no ink leakage occurs. The negative pressure valve 311 is not opened by the negative pressure on the sub-tank 310 side. Accordingly, no ink leakage occurs from this valve.
Alternatively, the ink supply port 506 may be moved to connect to the negative pressure valve 309.
In this state, the pump 304 is operated to generate negative pressure that is higher than presumed negative pressure in the sub-tank 310, and applies negative pressure to the negative pressure valve 311 via the negative pressure connection unit 306. Because of this negative pressure, a spring 311b of the negative pressure valve 311 loses out to negative pressure of the negative pressure connection unit 306 side so that a spherical valve 311a is opened, thereby increasing negative pressure in the sub-tank 310.
When the negative pressure of the sub-tank 310 is increased, the negative pressure causes a spherical valve 312a of the negative pressure valve 312 to compress a spring 312b to make an opening. That is, the negative pressure valve 312 is opened because pressure of an opposite side is smaller than the ink supply port 506 side of the negative pressure valve 312 by a predetermined or more than a predetermined amount. Further, negative pressure applied from the opened negative pressure valve 312 causes a spherical valve 309a of the negative pressure valve 309 to compress a spring 309b to make an opening. That is, the negative pressure valve 309 is opened because pressure of an opposite side is larger than an opening 404d side of the negative pressure valve 309 by a predetermined or more than a predetermined amount. As a result, the ink tank 101 is connected to the sub-tank 310 in the negative pressure state, and ink flows from the ink tank 101 into the sub-tank 310.
In this case, on the inkjet printing mechanism 504 side, the negative pressure valve 509 serves as a check valve that prevents reverse flowing of the ink or flowing-in of air from the nozzles of the inkjet printing mechanism 504.
According to the exemplary embodiment, a path of fluids from the supply port 307 connected to the ink tank 101 through the tube 308 to the negative pressure valve 309 corresponds to a first flow path. A path of fluids from the ink supply port 506 through the negative pressure valve 312 to the sub-tank 310 corresponds to a second flow path. The negative pressure of the sub-tank 310 opens the negative pressure valves 312 and 309 to cause the first and second flow paths to communicate with each other. Thus, the connection cam 316 and the pump 304 constitute a flow path connecting device. The connection cam 316 interconnects or separates the negative pressure valve 309 at the end of the first flow path and the supply port 307 at the end of the second flow path from each other. The pump 304 opens the negative pressure valves 312 and 309 to cause the first and second flow paths to communicate with each other.
When the predetermined amount of ink is supplied to the sub-tank 310, the main-body side supply mechanism 301 is separated from the carrier 206 side by rotation of the connection cam 316 to move to positions illustrated in
A phenomenon of ink scattering is observed when the sealing member 404 of the negative pressure valve 309 is separated from the backside 206a of the carrier 206 during a separation operation of the main-body side supply mechanism 301 from the carrier 206. As the ink flows through the negative pressure valve 309, the ink remains around the communication port 404a and scatters in association with the separation operation. A space of a predetermined volume is present between the opening 404d of the sealing member 404 of the negative pressure valve 309 and the ink supply port 506 of the backside 206a of the carrier 206 and the ink scatters to the space during the separation.
The scattered ink contaminates the print sheet 906. Moreover, an operation of each unit becomes unstable if the scattered ink is fixed.
The inventors have found out by experiment that almost no ink scattering occurs if the relative speed of the negative pressure valve 309 and the backside 206a of the carrier 206 is equal to or less than a predetermined speed at the time that the valve 309 and the carrier 206 are separated.
The inventors have also found out that the speed needs to be equal to or less than the above relative speed only within a predetermined distance from an abutting position and the speed can be increased without problems outside the predetermined distance.
According to the exemplary embodiment, as connection is made in a horizontal direction, the ink left around the communication port 404a side is collected in the lower side of the sealing member 404 under the influence of gravity.
In the case of separation at the speed of 20 mm/second and less, the ink collected in the lower side of the sealing member 404 is pulled to both sides while forming a bridge 601 between the sealing member 404 and the backside 206a of the carrier 206. When the bridge is cut off, almost all of the ink is sucked by either side and thus little ink scattering occurs.
In the case of separation at the speed higher than 20 mm/second, the ink collected in the lower side of the sealing member 404 is also pulled to both sides while forming a bridge between the sealing member 404 and the backside 206a of the carrier 206. However, in this case, since the separation speed is high, a bridge cutoff state is unstable, and ink droplets 602 which are not sucked to neither side are left and scatter.
The inventors have confirmed that the ink bridge is cut off when a distance (separation distance) between the sealing member 404 and the backside 206a of the carrier 206 is approximately 4 mm according to the exemplary embodiment.
When the separation distance is approximately 4 mm or less after the separation starts, the moving speed of the negative pressure valve 309 is controlled to be 20 mm/second or less. When the separation distance exceeds approximately 4 mm, no ink scatters. Accordingly, the negative pressure valve 309 can be moved at a speed higher than 20 mm/seconds. According to the exemplary embodiment, the speed is accelerated up to 50 mm/second.
In the graph labeled speed 1 in
In the graph of a speed 2, the speed of the negative pressure valve 309 is increased under constant acceleration so that the speed reaches 20 mm/second when the separation distance reaches approximately 4 mm. When the separation speed exceeds 4 mm, the speed is increased up to 50 mm/second under higher acceleration. No ink scattering was observed when control was performed at both the speeds 1 and 2.
The ink examined according to the exemplary embodiment has a normal viscosity of 3.3 (mPa·/S) at a normal temperature and surface tension of 31 (mN/m). In a low-temperature environment, the viscosity and the surface tension increase by 1.5 times. However, no change occurred in separation conditions. Thus, similar effects can be achieved in fluids whose viscosity is 4 mPa/seconds or less. Similar effects can also be achieved in fluids whose surface tension is 40 mN/m or less.
The sealing member 404 has a diameter of 5.5 mm as normal. However, due to variations of the components of the device, no change in separation conditions was observed up to about 6 mm. Accordingly, similar effects can be achieved if a diameter of a sealing surface of the sealing member 404 is 6 mm or less.
For the sake of brevity, the exemplary embodiment has been described in term of one color. The exemplary embodiment can also be applied to multiple colors without any problems. In that case, however, when a diameter of the sealing member 404 exceeds approximately 6 mm, the size of the carrier may have to increase.
In
According to the exemplary embodiment, the moving speed of the main-body side supply mechanism 301 is controlled based on the shape of the cam. However, the main-body side supply mechanism 301 may be driven and moved by the motor and the moving speed may be controlled by regulating a rotational speed of the motor. That is, during a predetermined period until a distance (separation distance) between the sealing member 404 and the backside 206a of the carrier 206 becomes 4 mm, the motor is driven at a first rotational speed. After a lapse of the predetermined period, the motor is driven at a second rotational speed that is higher than the first rotational speed.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions.
This application claims priority from Japanese Patent Application No. 2007-175294 filed Jul. 3, 2007, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-175294 | Jul 2007 | JP | national |
