Printer head in an ink jet system printer

An ink jet system printer has a printer head for emitting ink droplets toward a recording paper. Objectional ink mist is inevitably formed and diffused in various directions after the ink droplets impinge upon the recording paper. The printer head includes a first chamber for introducing the ink mist diffused in front of the printer head, a second chamber for accommodating an ink droplet issuance unit for emitting the ink droplets, and a fan system for creating an air flow directed from the first chamber to the second chamber, thereby effectively introducing the ink mist into the first chamber. A filter member is disposed in the first chamber for removing the ink mist introduced into the first chamber. The ink droplet issuance unit is disposed in the second chamber so that a stream of the ink droplets is inclined from a line perpendicular to the surface of the recording paper.

BACKGROUND AND SUMMARY OF THE INVENTION 
The present invention relates to a printer head in an ink jet system 
printer. 
In an ink jet system printer, ink droplets emitted from a nozzle are 
directed to a recording paper and impinge upon the recording paper. 
Objectionable ink mist is inevitably formed and diffused in various 
directions after the ink droplets impinge upon the recording paper. The 
thus generated ink mist will deteriorate the print quality by attaching to 
the recording paper, and affect the print accuracy by attaching to, for 
example, deflection electrodes. 
Accordingly, an object of the present invention is to provide a printer 
head for ensuring clean and accurate printing in an ink jet system 
printer. 
Another object of the present invention is to provide a printer head in an 
ink jet system printer for minimizing the occurrence of ink mist and 
removing the ink mist inevitably formed. 
Other objects and further scope of applicability of the present invention 
will become apparent from the detailed description given hereinafter. It 
should be understood, however, that the detailed description and specific 
examples, while indicating preferred embodiments of the invention, are 
given by way of illustration only, since various changes and modifications 
within the spirit and scope of the invention will become apparent to those 
skilled in the art from this detailed description. 
To achieve the above objects, pursuant to an embodiment of the present 
invention, an ink droplet issuance unit is secured in a casing which is 
driven to travel across the printing area. The ink droplet issuance unit 
is disposed in the casing in a manner that the axis thereof is slightly 
inclined toward the travel direction of the casing from the line 
perpendicular to the travel direction or the recording paper surface. 
Therefore, the ink droplet stream is slightly inclined from the line 
perpendicular to the recording paper surface, thereby minimizing the 
formation of the ink mist. A fan mechanism is disposed in the casing in 
order to introduce the ambience air from the front portion of the casing 
into the interior thereof. A filter is disposed in the course of the air 
flow created by the fan mechanism for removing the ink mist which is 
diffused in the ambience air.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, a printer head 10 is slidably mounted on parallel 
shafts 12 and 14, and driven to reciprocate along a recording paper 16 
through the use of a wire 18 which is extended between pulleys 20 and 22. 
The printer head 10 is fixed to a desired position of the wire 18, and a 
drive motor 24 is associated with the pulley 20. A cable 26 is secured to 
the printer head 10 to supply ink liquid and a control signal to an ink 
droplet issuance unit disposed in the printer head 10. 
FIG. 2 schematically shows the interior of the printer head 10. 
An ink droplet issuance unit 28 is disposed in the printer head 10. Ink 
droplets emitted from the ink droplet issuance unit 28 are deflected in 
accordance with charge amounts carried thereon while they pass through a 
constant high voltage field established by a pair of deflection electrodes 
30. The deflected ink droplets are directed to the recording paper 16 
through an opening 32 formed in the front wall of the casing of the 
printer head 10. Ink droplets not contributing to the actual printing 
operation are not deflected, but are directed to a beam gutter 34 for 
recirculation purposes. The ink droplet issuance unit 28 is disposed in 
the printer head 10 in a manner that the stream of the ink droplets is 
inclined with respect to a line perpendicular to the recording paper 16 by 
an angle .theta. as shown in FIG. 2. 
A partition wall 36 is disposed in the printer head 10 to divide the 
printer head 10 into a first chamber 38 and a second chamber 40. A fan 
system 42 is disposed in the printer head 10 for introducing the air from 
the first chamber 38 and developing the air toward the second chamber 40. 
An open end 44 is formed in the first chamber 38 for introducing the 
ambience air into the first chamber 38. A filter member 46 is disposed in 
the first chamber 38 for removing the ink mist included in the ambience 
air which is introduced into the first chamber 38 by the fan system 42 
through the open end 44. 
The ink droplet issuance unit 28 is disposed in the second chamber 40. 
Since the ink droplet issuance unit 28 is inclined toward the open end 44, 
the ink mist developed from the recording paper 16 is effectively 
introduced into the first chamber 38. The air flow introduced into the 
second chamber 40 is exhausted through the opening 32. Accordingly, the 
ink mist is not introduced into the second chamber 40 through the opening 
32. Therefore, there is no possibility that the ink mist will attach to, 
for example, the deflection electrodes 30. 
FIGS. 3 and 4 show the construction of the printer head 10 of the present 
invention in detail. 
The printer head 10 comprises a cover casing 50, a base member 52 and a 
front wall 54. The base member 52 includes a bed portion 56 for supporting 
the ink droplet issuance unit 28, and a circuit board 58 for supporting 
the control circuit of the ink jet system printer. The bed portion 56 
includes protrusions 60 and 62 to which the front wall 54 is fixed through 
the use of screws. Supporting elements 64 and 66 are secured to the bed 
portion 56 for supporting the ink droplet issuance unit 28 through the use 
of a shaft 68. 
The ink droplet issuance unit 28 comprises a nozzle assembly 70 for 
emitting ink droplets at a given frequency, and a charging tunnel 72 for 
charging the ink droplets in accordance with print information. A lower 
deflection electrode 74 is fixed to the ink droplet issuance unit 28. An 
angled member 76 is secured to the ink droplet issuance unit 28 through 
the use of a screw 78, the angled member 76 supporting an upper deflection 
electrode 80. The ink droplet issuance unit 28 is secured to the base 
member 52 through the use of the shaft 68 and a screw 82. A sring 84 is 
disposed below the ink droplet issuance unit 28, thereby adjusting the 
direction of the stream of the ink droplets through the use of the screw 
82. 
Wires 85 and 86 are provided for applying a constant high voltage between 
the upper deflection electrode 80 and the lower deflection electrode 74. A 
lead wire 88 is connected to the nozzle assembly 70 for applying a drop 
formation signal and a charging signal to an electromechanical transducer 
included in the nozzle assembly 70 and the charging tunnel 72, 
respectively. An ink conduit 90 is connected to the nozzle assembly 70 for 
supplying ink liquid to the nozzle assembly 70. The ink conduit 90 is 
connected to a coupler 92, which is connected to the cable 26 for 
introducing the ink liquid from an ink liquid reservoir into the nozzle 
assembly 70. The wires 85, 86 and 88 are also communicated with the cable 
26. The cable 26 is connected to the circuit board 58 via a connector 94. 
The front wall 54 comprises a protrusion 96 which is associated with the 
protrusions 60 and 62 for fixing the front wall 54 to the bed portion 56. 
An opening 98 is formed in the front wall 54, through which the deflected 
ink droplets are issued toward the recording paper 16. The beam gutter is 
secured to the front wall 54 for collecting the ink droplets not 
contributing to the actual printing operation. The ink liquid collected by 
the beam gutter is introduced into a groove 100 and returned to the ink 
liquid reservoir through a conduit 102 and the cable 26. A cut portion 104 
is formed in the front wall 54 to form an inlet for the air. 
FIG. 4 shows the interior of the cover casing 50. A partition wall 106 is 
disposed in the cover casing 50 to divide the interior into a first 
chamber 108 and a second chamber 110. The first chamber 108 is designed to 
communicate with the cut portion 104 formed in the front wall 54. The 
second chamber 110 is designed to accommodate the ink droplet issuance 
unit 28. Metal mesh plates 112 and 114 are disposed in the first chamber 
108 for supporting filter members 116 disposed therebetween. A fan system 
118 is disposed in the cover casing 50 for creating air flow directed from 
the first chamber 108 to the second chamber 110. More specifically, the 
ambience air is introduced through the cut portion 104 into the first 
chamber 108, and the ink mist is removed by the filter members 116. And, 
the clean air is introduced into the second chamber 110 and exhausted 
through the opening 98. 
The cover casing 50 is secured to the base member 52 through the use of 
supporting rods 120 and 122. The fan system 118 receives the power supply 
through connectors 124 and 126. The fan system 118 must have the ability 
to effectively introduce the ink mist diffused in front of the printer 
head 10, and not to disturb the ink droplet travel emitted from the 
issuance unit 28 and passing through the opening 98. A preferred fan 
system is a miniature fan, model "V241L", manufactured by Micronel AG. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the invention, and all such modifications are 
intended to be included within the scope of the following claims.