Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/07—Ink jet characterised by jet control
  • B41J2/075—Ink jet characterised by jet control for many-valued deflection
  • B41J2/08—Ink jet characterised by jet control for many-valued deflection charge-control type
  • B41J2/09—Deflection means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/07—Ink jet characterised by jet control
  • B41J2/075—Ink jet characterised by jet control for many-valued deflection
  • B41J2/095—Ink jet characterised by jet control for many-valued deflection electric field-control type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2202/00—Embodiments of or processes related to ink-jet or thermal heads
  • B41J2202/01—Embodiments of or processes related to ink-jet heads
  • B41J2202/10—Finger type piezoelectric elements

Definitions

• the present invention relates to an ink jet recording apparatus that achieves high density recording by spraying ink from a plurality of nozzle holes to enhance the concentration of ink drops on recording media such as paper and plastics.
• Fig. 4 shows a perspective view of the main parts of ink jet recording apparatus using a piezoelectric transducer-type ink jet head.
• a nozzle plate 7 is disposed on part of an actuator 6.
• On one side of the actuator 6 are a plurality of parallel bulkheads 6 made from piezoelectric ceramic, and which extend toward the nozzle plate 7.
• the bulkhead 6 has a plurality of ink channels 8. Sizes of the actuator 6 and bulkheads 9 need to be very precise. Therefore, they are integrally formed with the same piezoelectric ceramics material.
• On the nozzle plate 7 are a plurality of nozzle holes 10 correspondingly made with the channels 8 at regular intervals on a line.
• An actuator cover 14 is made from a ceramics material or a plastic material.
• the actuator cover 14 is formed such that along with the actuator
• ink jet head is constructed as described above.
• Signal electrodes 11 are formed by sputtering or vapor deposition on part of the actuator-cover side bulkheads 9.
• a printed circuit board 12 is connected to a voltage generating circuit (not illustrated) which generates voltage that changes voltage into pressure.
• Terminal electrodes 15 are disposed on the printed circuit board 12.
• a bonding wire 16 supplies voltage to the signal electrodes 11 via the terminal electrodes 15.
• the bulkheads 9 are polarized in the depth direction of the grooves, and are deformed depending on the amount of applied voltage on the signal electrodes 11.
• ink filling the channels 8 is sprayed selectively from the nozzle holes 10 which are connected to the channels 8.
• Fig. 5 shows a plan view illustrating a main part of a conventional ink jet head. In Fig. 5, ink drops 18 are sprayed from the nozzle holes 10.
• the ink drops 18 are sprayed at regular intervals, fly along paths 1 and parallel to one another and reach onto recording media 3.
• the pitch of the nozzle holes determines flying paths of the ink drops, and the ink drops reach onto the recording media along the flying paths.
• the pitch of the nozzle holes determines the resolution of recording.
• the pitch of the nozzle holes must be narrowed.
• machining of the bulkheads and the channels is difficult, since they are made of piezoelectric ceramic, and machining requires a blade using diamond abrasive.
• a density of the recording is limited with the ink jet head with the conventional construction.
• the ink jet recording apparatus of the present invention has a deflecting electrode for deflecting the pitch of ink jet drops sprayed from the nozzle holes.
• the ink jet recording apparatus also includes charging means for charging the ink drops.
• the deflecting electrode and nozzle holes move maintaining their positions relative to each other.
• the deflecting electrode is disposed on the ink jet head facing the back of the recording face of the recording media.
• pitch between the ink drops reaching onto the recording media can be narrowed without decreasing the pitch and sizes of the nozzle holes of the ink jet head.
• high-density recording becomes possible.
• Fig. 1A shows a front view of the main part of ink jet recording apparatus of a preferred embodiment of the present invention
• Fig. IB shows a side view of elements of the ink jet head
• Fig. 2 shows a plan view illustrating the flight paths of the ink drops ejected from the ink jet head of the ink jet recording apparatus of the present invention
• Fig. 3 shows a perspective view of the ink jet head of the ink jet recording apparatus of the present invention
• Fig. 4 shows a perspective view of the ink jet head of the prior art ink jet recording apparatus
• Fig. 5 shows a plan view illustrating the ink drops ejected from the ink jet head of the prior art ink jet recording apparatus.
• the ink jet recording apparatus of the present invention includes the following elements: a) an ink jet head with a plurality of nozzle holes, and which moves transversely to the delivering direction of the recording media; b) a deflecting electrode for deflecting ink drops sprayed from the nozzle holes, and which maintain relative positions with the nozzle holes; and c) a high voltage generator for applying high voltage to the deflecting electrode.
• the deflecting electrode is disposed on the ink jet head facing to the back of the recording face of the recording media.
• the ink jet recording apparatus of the present invention has a charging electrode near the nozzle holes for charging the ink drops if necessary, and a charging voltage generation means for applying voltage to the charging electrode.
• the construction of the ink jet recording apparatus of the present invention allows narrowing the pitch of the ink drops reaching onto the recording media, thereby achieving a high density recording.
• the deflecting electrode is disposed on the ink jet head facing the back of the recording face of the recording media, the deflecting electrode needs not to be disposed in the limited small space between the ink jet head and the recording media. Due to this disposition, the deflecting electrode does not obstruct the flying paths of the ink drops, thus allowing the deflecting electrode to be disposed at the optimal positions.
• Fig. 1A shows a front view of the main part of ink jet recording apparatus of a preferred embodiment of the present invention.
• a motor 21 rotates a feed screw A 25 via a gear A 22 and a gear B 23 which engages the gear A 22.
• a feed screw B 26 cut inversely to a feed screw A 25 rotates combined with a gear C 24.
• a rotating shaft 28 is a rotation centers of the feed screw A 25 and the feed screw B 26.
• a round-shaped electrode 29 is placed in a position facing approximately the center of a plurality of nozzle holes (described later) disposed in a line.
• the mounting board 30 holds the deflecting electrode 29.
• a guide 31 prevents flexure of the recording media 3.
• the feed screws A 25 and B 26 are placed parallel to each other. They are maintained such that they can rotate around the rotating shafts 28 that are supported by a frame 32.
• the recording media 3 In between an ink jet head 20 and the deflecting electrode 29 is the recording media 3 which is maintained by a platen roller 35.
• the platen roller 35 delivers the recording media 3.
• the ink jet head 20 and the mounting board 30 are driven together while their relative positions fixed by the feed screws A 25 and B 26. Therefore, relative positions of the deflecting electrode 29 and the nozzle holes are constantly maintained.
• a charging voltage generation means 36 generates charging voltage to be applied to a charging electrode (described later).
• a deflecting voltage generation means 37 applies high negative voltage to the deflecting electrode 29.
• Fig. IB shows a side view of elements of the ink jet head.
• an engaging section A 33 is disposed on the feed screw A 25 side of the ink jet head 20 and engages with valleys of the feed screw A 25. And, the engaging section A 33 sends the ink jet head 20 transversely to the delivering direction of the recording media 3 when the motor 21 rotates.
• An engaging section B 34 is disposed on the feed screw B 26 side of the mounting board 30 and engages with valleys of the feed screw B 26. And, the engaging section B 34 sends the mounting board 30 transversely to the delivering direction of the recording media 3 when the motor 21 rotates.
• the above-mentioned construction allows the ink jet head 20 and the deflecting electrode 29 to move transversely to the delivering direction of the recording media 3 by the motor 21.
• Fig. 2 shows a plan view illustrating the ink drops ejected from the ink jet head of the ink jet recording apparatus.
• a charging electrode 5 positively charges ink drops 18 sprayed from nozzle holes 10 as they pass through the charging electrode 5.
• the charging voltage generation means 36 illustrated in Fig. 1 applies voltage to the charging electrode 5.
• the round-shaped electrode 29 is applied with high negative voltage by the charging voltage generation means 37.
• the box-shaped charging electrode 5 surrounding all the nozzle holes 10 is hollow inside so that the ink drops 18 can pass through.
• the ink drops 18 are positively charged by the charging electrode 5, and electrostatically deflected by a high negative voltage between minus one thousands and minus several thousands of the deflecting electrode 29. If the surface of the recording media 3 is negatively charged and the potential of a round-shaped deflecting electrode 4 is low due to the deflecting electrode 29, neutralization occurs when the ink drops 18 are sprayed onto the recording media 3. As a result, electric force lines are changed leaving an insufficient deflection. In order to prevent such neutralizing effect, the potential of the deflecting electrode 4 should be desirably set between minus one thousands and minus several thousands.
• any kind of conventional high voltage generator can be used for the deflecting voltage generation means 37.
• the deflecting voltage generation means 37 simply provides an electric field, and does not require a large electric current, even a light weight and compact device such as a piezoelectric transformer can be used as the deflecting voltage generation means 37.
• the ink drops 18 reach the recording face of the recording media 3 via the flying paths 1 which converge into one spot toward the deflecting electrode 29 as illustrated in Fig. 2.
• intervals of the ink drops 18, namely the recording density can be changed, while maintaining the pitch of the nozzle holes 10 constant, by changing the relative distance between the nozzle holes 10 , the recording media 3 and the deflecting electrode 29.
• recording density on the recording media can be enhanced.
• a difficult machining of the ink jet head can be avoided.
• the recording density that has been conventionally determined by the pitch of the nozzle holes can be enhanced at remarkably low cost.
• the charging electrode 5 is a hollow box-shaped, however, the charging electrode 5 can be in any shape providing it charges and allows the ink drops 18 to pass through inside.
• Other possible charging means include corona charging, which can be utilized by introducing a metal mesh or fine metal lines applied by a high voltage near the nozzle holes 10. Blowing ion wind generated by an ion generating device near the nozzle holes 10 is another possible method.
• ink drops can be charged just by being ejecting from the nozzle.
• a conductive materials can also be used for the nozzle plate and make the potential of the ink drops 18 zero.
• a charging voltage generation means 36 for the charging electrode is not necessary.
• the ink drops 18 are positively charged, and the deflecting electrode negatively charged with high voltage.
• negatively charged voltage and positively charged high voltage can be applied to the charging electrode and deflecting electrode respectively.
• the ink jet head 20 and the mounting board 30 are driven by the same motor 21 in the description mentioned above. However, they can be driven by different motors.
• the ink jet head 20 and the mounting board 30 can be integrally formed.
• the ink jet recording apparatus of the present invention converges the ink drops toward the deflecting electrode by utilizing the ink jet head comprising the ink ejection heads, the charging electrode and the deflecting electrode. If necessary, the ink drops can be charged by charging means. With the construction of the present invention, recording density of the ink jet recording apparatus can be enhanced. As the ink jet recording apparatus of the present invention accelerates the ink drops charged by the charging means, an influence caused by the change in environmental factors such as air flow and temperature near the recording apparatus on the ink can be restricted. Thus, printing of even higher precision can be made possible.
• an ink jet recording apparatus which realize high recording density at low cost can be provided.
• significant industrial benefits can be expected.

Landscapes

• Particle Formation And Scattering Control In Inkjet Printers (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=18493744

Family Applications (1)

Country Status (5)

Cited By (2)

Families Citing this family (5)

Citations (3)

• 1998
  • 1998-12-25 JP JP10369169A patent/JP2000190505A/ja active Pending
• 1999
  • 1999-10-19 ID IDW20001606A patent/ID25617A/id unknown
  • 1999-12-22 CN CN99802194A patent/CN1288416A/zh active Pending
  • 1999-12-22 KR KR1020007009476A patent/KR20010041360A/ko not_active Application Discontinuation
  • 1999-12-22 WO PCT/JP1999/007217 patent/WO2000038930A1/en not_active Application Discontinuation

Patent Citations (3)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events