Patent Publication Number: US-6991311-B2

Title: Apparatus and method for introducing micro-volume liquid

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to an apparatus and method for introducing micro-volume liquid, and in particular, the invention relates to an introducing apparatus and method for a multi-channel inkjet print head. 
   2. Description of the Related Art 
   Methods for introducing micro-volume liquid into a print head are varied. For example, the liquid can be introduced into a reservoir thereof by pressuring, and then expelled out of orifices thereof. Such process, performed prior to actual deployment of the fluid, is referred to as priming. The purpose of priming is to saturate the print head and remove bubbles in channels thereof. In addition, other introducing methods are disclosed, for example, in U.S. Pat. Nos. 6,221,653, 6,458,583, 6,461,812, and 6,372,483. 
   For costly liquid, another introducing method is provided to reduce waste. In such introducing method, the nozzle plate of the print head first contacts the liquid. The liquid is then drawn into the reservoir from the nozzle plate by negative pressure. Thus, priming can be eliminated, and waste generated thereby can be reduced. Such method, however, can only introduce one kind of liquid at a time. Additionally, multiple reservoirs are required for different kinds of the liquid, and cross-contamination easily occurs between different reservoirs. 
   SUMMARY OF THE INVENTION 
   In view of this, the invention provides an apparatus and method for introducing liquid into a multi-channel inkjet print head. 
   Another purpose of the invention is to provide an apparatus and method for introducing a plurality of liquid at the same time. 
   Accordingly, the invention provides a method for introducing micro-volume liquid. The method includes the following steps. A multi-channel inkjet print head is provided. The multi-channel inkjet print head includes a cartridge and a nozzle plate with a plurality of nozzles. The cartridge includes a plurality of channels, communicating with the nozzles on the nozzle plate, and a plurality of openings located at the channels. The nozzle plate contacts a buffer. The buffer is introduced into the channels via the nozzles by providing a pressure. Reagents are introduced into the channels via the openings. 
   In a preferred embodiment, the buffer excludes biomolecules. 
   In another preferred embodiment, the method further includes the following step. After the buffer is introduced into the channels and filled the channels, part of the buffer is removed from the channels. It is noted that the volume of the removed buffer is not less than the volume of the introduced reagents. 
   In another preferred embodiment, the pressure is positive so that the buffer is pushed into the channels via the nozzle plate. 
   In another preferred embodiment, the pressure is negative so that the buffer is drawn into the channels via the openings. It is noted that the negative pressure is generated by vacuuming the openings. 
   In another preferred embodiment, the reagents include biomolecules therein, and biomolecules are oligonucleotides, peptides, proteins, or derivatives thereof. The reagents are introduced into the channels by pipettes. 
   In this invention, an apparatus for introducing micro-volume liquid is provided. The apparatus includes a multi-channel inkjet print head, a container, a pressure supply, and an injector. The multi-channel inkjet print head includes a cartridge and a nozzle plate with a plurality of nozzles. The cartridge includes a plurality of channels, communicating with the nozzles on the nozzle plate, and a plurality of openings located at the channels. The container receives a buffer. The buffer and the nozzle plate are in contact. The pressure supply communicates with the multi-channel inkjet print head, and provides pressure to the multi-channel inkjet print head so that the buffer is introduced into the channels. The injector communicates with the channels, and introduces reagents into the channels via the openings. 
   In a preferred embodiment, the apparatus further includes an absorber disposed in the channels to remove a predetermined amount of the buffer from the channels. 
   In another preferred embodiment, the pressure supply communicates with the container, and provides positive pressure to the container so that the buffer is pushed into the channels. 
   In another preferred embodiment, the pressure supply communicates with the openings, and provides a negative pressure to the channels so that the buffer is drawn into the channels. 
   It is noted that the injector may be a pipette. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
       FIG. 1  is a schematic view of an introducing apparatus as disclosed in a first embodiment of the invention; 
       FIGS. 2   a – 2   d  are schematic views of an introducing method as disclosed in a first embodiment of the invention; 
       FIGS. 3   a – 3   b  are schematic views of additional processes of the introducing method in  FIGS. 2   a – 2   d ; and 
       FIG. 4  is a schematic view of an introducing apparatus as disclosed in a second embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   First Embodiment 
   Referring to  FIG. 1 , an apparatus  100  for introducing micro-volume liquid as disclosed in a first embodiment of the invention is provided. The introducing apparatus  100  includes a multi-channel inkjet print head  110 , a container  120 , a pressure supply  130 , two injectors  140 ,  140 ′ (shown in  FIG. 2   c ), and two absorbers  150  (shown in  FIG. 3   a ). 
   The multi-channel inkjet print head  110  includes a nozzle plate  111  and a cartridge  112 . The nozzle plate  111  includes a plurality of nozzles  111   a . The cartridge  112  includes a plurality of channels  112   a , communicating with the nozzles  111   a  on the nozzle plate  111 , and a plurality of openings  112   b  located at the channels  112   a . It is understood that the multi-channel inkjet print head  110  further includes a chip and a barrier layer. Since these are conventional devices and less related to this invention, they are not labeled and their description is omitted. 
   The container  120  receives a buffer  200  therein, and is sealed by an O-ring  121 . The buffer  200  is a common ingredient for various reagents to be introduced into the channels  112   a , and excludes biomolecules. Referring to  FIG. 1 , the pressure supply  130  communicates with the multi-channel inkjet print head  110  via the container  120 . The pressure supply  130  provides positive pressure to the container  120  so that the buffer  200  is pushed and introduced into the channels  112   a  of the multi-channel inkjet print head  110  via the nozzles  111   a  on the nozzle plate  111 . 
   As shown in  FIG. 2   c , each injector  140  and  140 ′ is disposed in the channel  112   a , and introduces reagents  300  and  300 ′ into the channels  112   a  via the openings  112   b  respectively. Each reagent  300  is provided in a higher concentration, and includes biomolecules therein. The biomolecules may be oligonucleotides, peptides, proteins, or derivatives thereof. The injector  140  may be a pipette. Although two injectors  140  and  140 ′ are shown in  FIG. 2   c , the number of the injectors  140  is not limited to this. Based on the number of the channels  112   a , the number of the injectors  140  is adjustable. 
   As shown in  FIG. 3   a , each absorber  150  is disposed in a channel  112   a  to remove a predetermined amount of the buffer  200  therefrom. Although two absorbers  150  are shown in  FIG. 3   a , the number of the absorbers  150  is not limited to this. Based on the number of the channels  112   a , the number of the absorbers  140  is adjustable. 
   The structure of the introducing apparatus  100  is described as above, and the introducing method using the introducing apparatus  100  is described in the following. 
     FIGS. 2   a – 2   d  show a method, for introducing micro-volume liquid, as disclosed in the invention. The introducing method includes the following steps. The multi-channel inkjet print head  110 , the container  120 , the pressure supply  130 , and the injectors  140  are first provided. The nozzle plate  111  of the multi-channel inkjet print head  110  then contacts the buffer  200  in the container  120  via the O-ring  121  as shown in  FIG. 2   a . Sequentially, as shown in  FIG. 2   b , the pressure supply  130  provides positive pressure to the container  120  so that the buffer  200  is pushed and introduced into the channels  112   a  via the nozzles  111   a  on the nozzle plate  111 . Finally, the injectors  140  are disposed in the channels  112   a  as shown in  FIG. 2   c , and the reagents  300  and  300 ′ in the injectors  140  and  140 ′ respectively are then introduced into the channels  112   a  through the openings  112   b . Different kinds of the reagents  300  can be introduced into different channels  112   a  at the same time or in a predetermined order. 
   To adjust the amount of the buffer  200 , the method may further include the following steps. Subsequent to introducing the buffer  200  into the channels  112   a , the absorbers  150  are disposed in the channels  112   a  as shown in  FIG. 3   a . Part of the buffer  200  is then removed from the channels  112   a  as shown in  FIG. 3   b . The volume of the removed buffer  200  is not less than the volume of the reagents  300  to be introduced. 
   In the invention, the print head is saturated by the buffer, thus preventing waste of reagents. Additionally, since the channels are saturated at the same time, time required by priming can be reduced. Moreover, different kinds of the reagents can be introduced into the channels separately at the same time, thus avoiding cross-contamination. 
   Second Embodiment 
   Referring to  FIG. 4 , an apparatus  100 ′ for introducing micro-volume liquid as disclosed in a second embodiment of the invention is provided. The introducing apparatus  100 ′ includes a multi-channel inkjet print head  110 , a container  120 , a pressure supply  130 ′, two injectors (not shown), two absorbers (not shown), and a buffer supply  160 . Devices of the second embodiment that are the same as those of the first embodiment are presented by the same references, and their description is omitted. 
   The second embodiment differs from the first embodiment in that the pressure supply  130 ′ communicates with the openings  112   b  of the multi-channel inkjet print head  110 , and provides negative pressure to the channels  112   a  so that the buffer  200  is drawn into the channels  112   a  from the buffer supply  160 . 
   That is, to introduce the buffer  200  into the channels  112   a  in the introducing method of this embodiment, the pressure supply  130 ′ provides negative pressure to the openings  112   b  so that the buffer  200  is drawn into the channels  112   a . It is noted that the negative pressure may be generated by vacuuming the openings. 
   While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.