WO1999007555A1

WO1999007555A1 - Printing machine with vaccuum clamping of substrate using compressed air

Info

Publication number: WO1999007555A1
Application number: PCT/AU1998/000618
Authority: WO
Inventors: Stuart Saunders
Original assignee: Stuart Saunders
Priority date: 1997-08-07
Filing date: 1998-08-06
Publication date: 1999-02-18

Abstract

A printing machine with a vacuum screen table (1) for vacuum clamping of work material or work piece wherein vacuum for clamping is provided by compressed air. Vacuum created by vacuum generator (13) is applied to screen table (1) and may be modulated (on-off) by movement of the screen (3), and an accumulator (10) between throttle valve (8) and pneumatic switch (11) effects fast clamping. Closing exhaust of generator as screen rises directs compressed air into table to float or lift printed part. Regulator/throttle valve (8) sensing vacuum in table and controlling compressed air flow minimises air consumption. An audible warning device on exhaust may indicate correct sealing of part or material to be printed. Table adjustment screws (6) incorporate spherical surface between screw end and swivel foot to facilitate fine adjustment.

Description

INTERNATIONAL SEARCHREPORT International application No PCT/AU 98/00618

CLASSIFICATION OF SUBJECT MATTER

Int Cl⁶ B41F 15/20

According to International Patent Classification (IPC) or to both national classification and IPC

B. FIELDS SEARCHED

Minimum documentation searched (classification system followed by classification symbols) IPC B41F 15/20, 1/32, B41L 29/18, B41M 1/12

Documentation searched other than minimum documentation to the extent that such documents are mcluded m the fields searched AU IPC as above

Electromc data base consulted during the international search (name of data base and, where practicable, search terms used)

WPAT

JAPIO

C. DOCUMENTS CONSIDERED TO BE RELEVANT

Category* Citation of document, with indication, where appropnate, of the relevant passages Relevant to claim No

US 5582104 A (BEST et al) 10 December 1996

X Whole document 1-7, 9, 10

US 3972523 A (BRAJNDES) 3 August 1976

X Whole document

WO 90/10770 A (NEW SPIRIT INC ) 20 September 1990

X Pages 5 and 6, figures 2, 7, and 8 Discloses Swivel foot device

X I Further documents are listed m the X I See patent family annex contmuation of Box C

* Special categones of cited documents „„„ later document published after the international filing date or

"A" document defining the general state of the art which is priority date and not in conflict with the application but cited to not considered to be of particular relevance understand the principle or theory underlying the invention "E" earlier application or patent but published on or after "X" document of particular relevance, the claimed invention cannot the international filing date be considered novel or cannot be considered to involve an "L" document which may throw doubts on priority claιm(s) inventive step when the document is taken alone or which is cited to establish the publication date of " Y" document of particular relevance, the claimed invention cannot another citation or other special reason (as specified) be considered to involve an mventive step when the document is "O" document referring to an oral disclosure, use, combmed with one or more other such documents, such exhibition or other means combination bemg obvious to a person skilled m the art "P" document published pπor to the international filing "&" document member of the same patent family date but later than the pnoπty date claimed

Date of the actual completion of the international search Date report 30 September 1998

Name and mailing address of the ISA/AU Authorized officer .--₎

AUSTRALIAN PATENT OFFICE

PO BOX 200

WODEN ACT 2606 ADRIANO GIACOBETTI

AUSTRALIA

Facsimile No (02) 6285 3929 Telephone No (02) 6283 2579

Form PCT/ISA/210 (second sheet) (July 1998) copder INTERNATIONALSEARCHREPORT International application No. PCT/AU 98/00618

C (Continuation). DOCUMENTS CONSIDERED TO BE RELEVANT

Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No.

DE 3412605 A (A-Z AUSRUSTUNG UND ZUBEHOR GMBH & Co. KG) 17 October 1985 Figures 1 to 6: Discloses swivel foot device

Derwent Abstract Accession No. 90-183200/24, class Q38 SU 1525118 A (DEMYANOVICH) 30 November 1989

X Abstract Only: Discloses swivel foot device.

Form PCT/ISA/210 (continuation of second sheet) (July 1998) copder INTERNATIONALSEARCHREPORT International application No PCT/AU 98/00618

Box 1 Observations where certain claims were found unsearchable (Continuation of item 1 of first sheet)

This international search report has not been estabhshed in respect of certain claims under Article 17(2)(a) for the following reasons

1 I I Claims Nos because they relate to subject matter not required to be searched by this Authority, namely

D Claims Nos because they relate to parts of the international application that do not comply with the prescnbed requirements to such an extent that no meaningful international search can be earned out, specifically

3 I [ Claims Nos because they are dependent claims and are not drafted in accordance with the second and third sentences of Rule 6 4(a)

Box II Observations where unity of invention is lacking (Continuation of item 2 of first sheet)

This International Searching Authonty found multiple inventions in this international application, as follows

1 Claims 1-7, 9 and 10 directed to a printing machine with a vacuum table,

2 Claim 8 directed to a printing machine with movable table, as reasoned on the extra sheet

I As all reqmred additional search fees were timely paid by the applicant, this international search report covers all searchable claims fχ~| As all searchable claims could be searched without effort justifying an additional fee, this Authonty did not invite payment of any additional fee

As only some of the reqmred additional search fees were timely paid by the applicant, this international search report covers only those claims for which fees were paid, specifically claims Nos

I No required additional search fees were timely paid by the applicant Consequently, this international search report is restricted to the invention first mentioned in the claims, it is covered by claims Nos

Remark on Protest J The additional search fees were accompanied by the applicant's protest

I I No protest accompanied the payment of additional search fees

Form PCT/ISA/210 continuation of first sheet l Jul 1998 co de INTERNATIONAL SEARCHREPORT International application No. PCT/AU 98/00618

Box

Continuation of Box II:

The international application does not comply with the requirements of unity of invention because it does not relate to one invention or to a group of inventions so linked as to form a single general inventive concept. In coming to this conclusion the International Searching Authority has found that there are different inventions as follows:

1. Claims 1-7, 9 and 10 are directed to a printing machine including a vacuum table for vacuum clamping the material by means of a compressed air operation. It is considered that the means of a compressed air operation to create the vacuum clamping comprises a first "special technical feature".

2. Claims 8 is directed to a printing machine with a movable table which is effected by rotation of screws having swivel feet. It is considered that the particular features of the screws and swivel feet on the base of the screws comprises a second "special technical feature".

Since the abovementioned groups of claims do not share any of the technical features identified, a technical relationship between the inventions does not exist. Accordingly the claims do not relate to one invention or to a single inventive concept, a priori.

INTERNATIONAL SEARCHREPORT International application No.

Information on patent family members PCT/AU 98/00618

This Annex lists the known "A" publication level patent family members relating to the patent documents cited in the above-mentioned international search report. The Australian Patent Office is in no way liable for these particulars which are merely given for the purpose of information.

Patent Document Cited in Search Patent Family Member Report

US 5582104 us 5284189 us 3972523 DE 2453753 GB 1489161

WO 90/10770 AU 52690/90 CA 1291470 EP 463005

US 5056753

END OF ANNEX

Form PCT/ISA/210 extra sheet Jul 1998 co der PRINTING MACHINE WITH VACUUM CLAMPING OF SUBSTRATE USING COMPRESSED AIR.

This invention provides a printing machine including vacuum clamping of the part or substrate to be printed. Vacuum clamping is provided by compressed air.

A description of the claimed invention follows, to be read in conjunction with the attached drawing. This vacuum printer is most readily described in the application of a standard manual screen printer. However, it can readily be applied to other kinds of printers requiring vacuum clamping including automatic screen printers and in line screen printers, and rotogravure and offset printers.

Many υπipυiien υf lite claimed iitveiiliυii are similar lυ a υiiveitliυnal vacuum screen printer. The main parts are, with reference to drawing #1;

1) The Screen Table. This is located on the top of the machine and can be moved by the adjusting screws (6).

2) The Vacuum Plate.

The part, sheet, substrate or film to be printed is placed on the vacuum plate on the top of the table, and is vacuum clamped by a partial vacuum transferred from the vacuum chamber below through the holes in the vacuum plate.

3) The Screen.

A pattern of open areas and stopped areas in the mesh of the screen selectively passes the ink to the part to be printed. 4) Adjustable Height Support Hinge.

The hinge allows the screen to be raised and lowered. The adjustable height facility allows the clearance of the screen to be adjusted.

5) Counterweight.

This holds the screen in the up position when changing the printed part. The centre of gravity of the screen / counterweight system is located above the hinge and forward of the hinge when screen is down, and above and behind the hinge when the screen is raised. This provides a bistable location of the screen which allows for the part to be removed after printing, and a new part to be placed. 2

6) Fore and aft, and lateral adjusting screws.

The screw has a knob on the outer end, and a swivel foot on the inner end. The swivel foot bears on the sides of the screen table. A boss on the sides of the base has a threaded hole through which the screw passes. Adjustment of the screws allows for fine adjustment of the location of the printed areas on the part being printed (the registration). The screws may incorporate a substantially spherical contact surface between the screw and the swivel foot to eliminate undesirable unbalanced forces being transferred to the table during adjustment which can cause difficult adjustment. The difference between the conventional vacuum screen printer and the claimed invention is in the following components.

7) Hose; compressed air supply.

8) Adjustable throttle valve, (this may include a regulator controlled by the vacuum level in the table). 9) Hose; valve to switch.

10) Accumulator. [Provided in this case by an appropriately excess length of hose between throttle valve (9) and pneumatic switch (11)]

11) Pneumatic switch and auto operating pin.

12) Hose; switch to generator. 13) Vacuum generator.

14) Vacuum generator outlet modulator.

15) Vacuum generator outlet silencer.

16) Vacuum table feedback hose.

Filtered and regulated compressed air is provided to the machine through hose (7). This is controlled through throttle valve (8), before passing through the hose (9) to pneumatic switch (11). This switch may be connected to the screen via an automatic operating pin or by a cable, or by other suitable means such as electric switch and solenoid, such that a downward movement of the screen (3) causes the pneumatic switch to open, passing compressed air to the vacuum generator (13). When the screen is raised, the switch will close, cutting off the air supply. The compressed air supply also may be manually operated, e.g. by hand or foot switch.

Claims

3 The compressed air flowing through the vacuum generator draws air frorrr the vacuum chamber in the vacuum table. This lowers the air pressure in the chamber, which causes the substrate or part on top of the vacuum plate to be held onto the plate by transfer of the chamber vacuum to the underside of the part or substrate through the holes in the vacuum plate, with the greater (atmospheric) air pressure above.

Throttle valve (S) may automatically compensate for the level of vacuum in the vacuum table by employing feedback of the table vacuum to a diaphragm or piston assembly which automatically modulates the amount of compressed air flowing into the vacuum generator, to economise the amount of compressed air used.

Exhaust from the vacuum generator may be blocked at a certain position of the screen (e.g. just below the full up position) by the vacuum generator modulator (14), to redirect the compressed air into the vacuum table to pressurise vacuum table, and release printed part. Vacuum generator modulator (14) may be located adjacent vacuum generator (13) and operated remotely by e.g. cable, or it may be located near switch (11) and operated directly by switch operating pin. Exhaust is silenced by the silencer (15), or it may discharge directly to the atmosphere. When the screen is in the up position, the compressed air is again cut off by switch (11)

Parts 7 - 12 are common in the industry; item 13, is industrially available, but is apparently not commonly known. This device is known as a vacuum generator. It is powered by compressed air, and creates a vacuum. It has three ports; one port is connected to the vacuum chamber under the screen table. Another port is connected to the compressed air source, and the third port is the exhaust.

Development and refinement has the claimed invention now performing better than conventional vacuum screen tables. Further details of this invention will become apparent in the following description of the operation.