EP0997285A1

EP0997285A1 - Inkjet nozzle aligning apparatus

Info

Publication number: EP0997285A1
Application number: EP98250381A
Authority: EP
Inventors: Tse-Chi Mou; Shi-Kd Fan; Jung-Hsiang Hsu; Jing-Yuan Ho
Original assignee: Microjet Technology Co Ltd
Current assignee: Microjet Technology Co Ltd
Priority date: 1998-10-22
Filing date: 1998-10-29
Publication date: 2000-05-03
Also published as: CA2251293A1; CA2251293C

Abstract

An aligning apparatus is disclosed for use with an inkjet nozzle device having a nozzle chip and a nozzle plate in order to automatically align the nozzle chip (21) and the nozzle plate (22) for enabling the nozzle plate to be properly placed on the nozzle chip. The apparatus includes a positioning device (91) for positioning the nozzle chip and the nozzle plate, a position-determining device (90) for determining positions of the nozzle chip and the nozzle plate and outputting position signals corresponding thereto, and a controller (25) outputting a control signal for controlling the positioning device in response to the position signals.

Description

FIELD OF THE INVENTION

The present invention relates to an aligning apparatus, and more particularly to one used for an inkjet nozzle.

BACKGROUND OF THE INVENTION

The technology always gets developed with which we find no exception for the printer which is evolved from the dot-matrix one to the inkjet one, and further to the laser one. As the inkjet one is more economical than the laser one, the inkjet printer still plays an important role in nowaday market.
The inkjet nozzle in an inkjet printer includes a nozzle chip and a nozzle plate which are aligned as follows according to the conventional technique:
As shown in Fig. 1, the operator uses his right hand (RH) to control the programmable logic controller (PLC) controller 11 to actuate the feeding mechanism 12 for transmitting the nozzle chip and the nozzle plate to the positioning device 15 by which the nozzle plate is sucked above the nozzle chip by a sucker. The charge coupled device (CCD) 18 will transmit images of the nozzle chip and the nozzle plate through the image interface 17 to the screen 16 of a personal computer 13 in order that the operator can thereafter begin to proceed the dull aligning operation for the nozzle chip and the nozzle plate according to the position difference thereof on screen 16. Specifically, the operator uses his left hand (LH) to select a specific control key on the keyboard of computer 13 for signalling the driving circuit 14 to translate and/or rotate positioning device 15 for adjusting the position of the nozzle chip until screen 16 shows that positions of the nozzle chip and the nozzle plate coincide with each other. Finally, the nozzle plate is placed on the nozzle chip.
It can be found from the above descriptions that:
1) The optical, feeding and aligning systems/mechanisms respectively for RH, LH and EYE are inter-independent so that they must be operated separately;
2) Every procedure involves in an inaccurate artificial judgement whether the preceding procedure has been effectively finished; and
3) Such aligning procedure is laborious and time-consuming.
It is therefore attempted by the applicant to overcome the shortcomings encountered by the prior art.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide an automatical aligning apparatus for the inkjet nozzle.
It is another object of the present invention to provide an accurate aligning apparatus for the inkjet nozzle.
It is further an object of the present invention to provide a convenient and effective aligning apparatus for the inkjet nozzle.
According to the present invention, an aligning apparatus used for an inkjet nozzle having a nozzle chip and a nozzle plate for aligning the nozzle chip and the nozzle plate to enable the nozzle plate to be properly placed on the nozzle chip includes a positioning device for positioning the nozzle chip and the nozzle plate, a position-determining device for determining positions of the nozzle chip and the nozzle plate and outputting position signals corresponding to the positions, and a controller electrically connected to said positioning device and said position-determining device and outputting a control signal for controlling the positioning device in response to the position signals.
Preferably the present aligning apparatus further includes a driver electrically connected between the controller and the positioning device for amplifying the control signal to drive the positioning device.
Preferably the present aligning apparatus further includes a sensing interface electrically connected between the controller and the positioning device for sensing the position signals to be used by the controller.
Certainly, according to the present ivention, the position-determining device can determine the positions by optical images of the nozzle chip and the nozzle plate.
In accordance with an aspect of the present invention, the position-determining device includes a charge coupled device for reading the optical images of the nozzle chip and the nozzle plate on the positioning device, and an image processor electrically connected to the charge coupled device for processing the optical images to obtain the position signals.
In the present aligning apparatus, the nozzle plate can be generally rectangular and have a first diagonal. In a specific embodiment, the position of the nozzle plate can be determined by two points on the diagonal and an angle included by the diagonal and a reference horizontal axis. By the same token, the nozzle chip can have a generally rectangular surface having a second diagonal for placing thereon the nozzle plate. Similarly, the position of the nozzle chip can be determined by two points on the second diagonal and an angle included by the second diagonal and a reference horizontal axis.
Certainly, the controller can be a personal computer. According to the present aligning apparatus, the positioning device can include a rotatable and two-dimensionally translatable placing device for placing thereon nozzle chip and adjusting thereat the position of the nozzle chip, a sucker sucking thereto the nozzle plate, a driving device enabling the placing device to be rotatable and two-dimensionally translatable for aligning the nozzle chip with the nozzle plate, and a position encoder electrically connected to the placing device for encoding the position signals of the nozzle chip and the nozzle plate.
Certainly, the driving device can include a plurality of motors.
The present invention may best be understood through the following descriptions with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 is a block diagram showing how an operator aligns the nozzle chip with the nozzle plate according to the prior art;
Fig. 2 is a block diagram schematically showing how a preferred embodiment of an aligning apparatus according to the present invention functions;
Fig. 3 is a schematical view showing the procedures that an aligning apparatus in Fig. 2 proceeds the aligning operations; and
Fig. 4 is a flow chart showing how an aligning apparatus in Fig. 2 proceeds the aligning operations.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENT

Referring now to Fig. 2, there is shown a block diagram schematically showing how a preferred embodiment of an aligning apparatus according to the present invention functions, which is used for an inkjet nozzle having a nozzle chip 21 and a nozzle plate 22 for aligning nozzle chip 21 and nozzle plate 22 to enable nozzle plate 22 to be properly placed on nozzle chip 21. The present aligning apparatus includes a positioning device 91 having a positioning mechanism 93 for positioning nozzle chip 21 and nozzle plate 22, a position-determining device 90 electrically connected to positioning device 91 to determine positions of nozzle chip 21 and nozzle plate 22 and outputting position signals corresponding to positions of nozzle chip 21 and nozzle plate 22, a controller 25 electrically connected to positioning device 91 and position-determining device 90 and outputting a control signal for controlling positioning device 91 in response to the position signals, a driver 26 electrically connected between controller 25 and positioning device 91 for amplifying the control signal to drive positioning device 91, and a sensing interface 30 electrically connected between controller 25 and positioning device 91 for sensing the position signals to be used by controller 25. Position-determining device 90 can determine positions of nozzle chip 21 and nozzle plate 22 by optical images thereof and can include a charge coupled device (CCD) 23 for obtaining images of nozzle chip 21 and nozzle plate 22 on positioning mechanism 93 having a sucker 40 sucking thereto nozzle plate 22, and an image processor 24 electrically connected to charge coupled device 23 for processing the optical images of nozzle chip 21 and nozzle plate 22 to obtain position signals therefor. Image processor 24 can be a part of the system program or software for processing the image.
Controller 25 can be a personal computer by which one can additionally control materials, and/or analyze the yield rate and/or the rejection rate by introducing therein the relevant software skill. For example, before proceeding the aligning procedure, one can design the personal computer to judge whether the fed materials are defective and/or should be rejected.
Driver 26, which can be some kind of control module, generally includes transistors and are provided in this particular embodiment in order to get an enough current to drive the driving device 27 as will be described hereinafter. Sensing interface 30 can include several photosensors for sensing the position of the nozzle chip 21 to be transmitted to controller 25 for processing.
Nozzle plate 22 can generally be rectangular or defined to have a rectangular portion so that the position of nozzle plate 22 can be determined by two points on the diagonal thereof and an angle included by the diagonal and a reference horizontal axis. By the same token, nozzle chip 21 can also have a corresponding generally rectangular surface having a second diagonal for placing thereon nozzle plate 21 so that the position of nozzle chip 21 can be determined by two points on the second diagonal and an angle included by the second diagonal and a reference horizontal axis.
Positioning mechanism 93 in this particular embodiment can include a rotatable and two-dimensionally translatable placing device 28 for placing thereon nozzle chip 21 and adjusting thereat the position of nozzle chip 21, sucker 40, driving device 27 which is electrically connected between driver 26 and placing device 28 and can include a plurality of motors for respectively enabling placing device 28 to be rotatable and two-dimensionally translatable for aligning nozzle chip 21 with nozzle plate 22, and a position encoder device 29 which is electrically connected to placing device 28 and can include a plurality of position encoders, e.g. optical rulers for X/Y-axis movement or an optical angle encoder for angular movement, for encoding the position signal of placing device 28 or nozzle chip 21 moved by driving device 27. It goes without saying that the resolution of position encoder device 29 decides the precision thereof. In this particular embodiment, we place nozzle chip 21 on placing device 28 which is operated to translate and/or rotate nozzle chip 21 to be aligned with nozzle plate 22 sucked by sucker 40. It is readily conceivable to one skilled in the art that alternatively, we can place nozzle plate 22 on placing device 28 to be rotated and/or translated to be aligned with nozzle chip 21 somehow secured to positioning mechanism 93.
Referring now to Fig. 3, we will in the following describe how an aligning apparatus according to the present invention proceeds the aligning operation.
31: At first, we find the position of nozzle plate 22 sent from the feeding mechanism by position-determining device 90 by locating points A, B on a diagonal of nozzle plate 22 and an angle 1 included by the diagonal and the horizonal axis.
32: Then, on the XY coordinates, i.e. the abscissa and the ordinate, we mark points A, B.
33: We find the position of nozzle chip 21 sent from the feeding mechanism by position-determining device 90 by locating points C, D on a diagonal of nozzle chip 21 and an angle 2 included by the diagonal and the horizonal axis.
34: Controller 25 sends a control signal to drive positioning mechanism 93 to rotate according to the difference between 1 and 2 in order that 1 and 2 coincide with each other.
35: Controller 25 sends a control signal to drive positioning mechanism 93 to translate along the abscissa according to the horizontal difference between nozzle chip 21 and nozzle plate 22.
36: Finally, controller 25 sends a control signal to drive positioning mechanism 93 to translate along the ordinate according to the vertical difference between nozzle chip 21 and nozzle plate 22 to complete the aligning operation.
Referring now to Fig. 4, there is shown a flow chart showing how an aligning apparatus according to the present invention proceeds the aligning operations which includes:
61: Sending nozzle chip 21 and nozzle plate 22 to be respectively attached to placing device 28 and sucker 28.
62: Obtaining the image of nozzle plate 22 by CCD 23.
63: Image-processing the images of nozzle chip 21 and nozzle plate 22 by image processor 24 to obtain the positions (A, B and C, D) thereof.
64: Determining whether the positions (A, B, and C, D) coincide with each other, if yes, come to an end; if not, go to step 65.
65: Adjusting the position of nozzle chip 21 on positioning mechanism 93 until the positions (A, B, and C, D) coincide with each other.
While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
Therefore, the above description and illustration should not be taken as limiting the scope of the present invention which is defined by the appended claims.

Claims

An aligning apparatus used for an inkjet nozzle having a nozzle chip and a nozzle plate for aligning said nozzle chip and said nozzle plate to enable said nozzle plate to be properly placed on said nozzle chip, comprising:

a positioning device for positioning said nozzle chip and said nozzle plate;

a position-determining device for determining positions of said nozzle chip and said nozzle plate and outputting position signals corresponding to said positions; and

a controller electrically connected to said positioning device and said position-determining device and outputting a control signal for controlling said positioning device in response to said position signals.
An aligning apparatus according to claim 1, further comprising a driver electrically connected between said controller and said positioning device for amplifying said control signal to drive said positioning device.
An aligning apparatus according to claim 1, further comprising a sensing interface electrically connected between said controller and said positioning device for sensing said position signals to be used by said controller.
An aligning apparatus according to claim 1 wherein said position-determining device determines said positions by optical images of said nozzle chip and said nozzle plate.
An aligning apparatus according to claim 4 wherein said position-determining device includes:

a charge coupled device for reading said optical images of said nozzle chip and said nozzle plate on said positioning device; and an image processor electrically connected to said charge coupled device for processing said optical images to obtain said position signals.
An aligning apparatus according to claim 1 wherein said nozzle plate is generally rectangular and has a first diagonal.
An aligning apparatus according to claim 6 wherein said position of said nozzle plate is determined by two points on said diagonal and an angle included by said diagonal and a reference horizontal axis.
An aligning apparatus according to claim 6 wherein said nozzle chip has a generally rectangular surface having a second diagonal for placing thereon said nozzle plate.
An aligning apparatus according to claim 8 wherein said position of said nozzle chip is determined by two points on said second diagonal and an angle included by said second diagonal and a reference horizontal axis.
An aligning apparatus according to claim 1 wherein said controller is a personal computer.
An aligning apparatus according to claim 1 wherein said positioning device includes:

a rotatable and two-dimensionally translatable placing device for placing thereon nozzle chip and adjusting thereat said position of said nozzle chip;

a sucker sucking thereto said nozzle plate;

a driving device enabling said placing device to be rotatable and two-dimensionally translatable for aligning said nozzle chip with said nozzle plate; and

a position encoder electrically connected to said placing device for encoding said position signals.
An aligning apparatus according to claim 11 wherein said driving device includes a motor.