GB2304310A - Device for cleaning screen plate used in screen printing - Google Patents

Abstract

A cleaning device (10F,Fig.4) is disclosed capable of cleaning a screen plate (S,Fig.4) used in screen printing, said cleaning device (10F,Fig.4) comprises a housing (170,Fig.4) having an opening (170a,Fig.4), a shaft (172,Fig.2) being disposed within the housing (170,Fig.4), the shaft (172,Fig.4) having a plurality of blades (174,Fig.4) disposed thereabout at regular intervals. The blades (174,Fig.4) are projected from the opening (170a,Fig.4) of the housing (170,Fig.4) so that the blades (174,Fig.4) contact a lower surface of a screen plate (S,Fig.4) so as to remove any ink residue from the screen plate (S,Fig.4). A pipe (186,Fig.5) having resiliently deformable strips (188a,188b,Fig.5) mounted thereon is arranged below the shaft (172,Fig.4), the strips (188a,188b,Fig.5) are contactable with the blades (174,Fig.4). A tube (190,Fig.5) supplies solvent to the strips (188a,188b,Fig.4) via the pipe (186,Fig.5) thus assisting in the removal of ink residue from the blades (174,Fig.4) as contact is made with the strips (188a,188b,Fig.5). A drive mechanism for the shaft (172,Fig.4) is also disclosed (see Fig.5).

Description

DEVICE FOR CLEANING SCREEN PLATE USED IN SCREEN PRINTING The present invention relates in general to screen printing and more specifically to a device for cleaning a screen plate used in the screen printing.

For printing electric circuit patterns on an insulating base board, so-called "screen printing" has been hitherto used. The printing system employed in this printing comprises generally a screen plate (or mesh screen plate) which is put on an insulating base board to be printed, and a squeegee (viz., ink squeezing device) which runs on the screen plate while squeezing a given amount of viscous conductive ink onto the screen plate and pressing the screen plate against the insulating base board. With this, a desired circuit pattern of the conductive ink is printed on the surface of the insulating base board, which pattern coincides with a perforated print pattern defined by the screen plate. The base board thus printed is then removed from the screen plate and heated for fixing the printed circuit pattern.The screen plate is constructed of a stainless steel mesh or the like.

For improving the quality of the printed pattern on the base board, it is necessary to clean the screen plate at certain intervals.

Hitherto, various cleaning devices have been proposed and put into practical use for such purpose. However, due to their inherent constructions, some of them fail to exhibit a satisfactory cleaning effect and some are costly.

It wool Therefore be Aeslra~le to ie aol to provide a screen cleaning device or use in the screen printing, which is free of te above-mentioned drawbacks.

According to a first aspect of the present invention, there is provided a cleaning device for cleaning a screen plate used in a screen printing, which comprises a base structure placed just below the screen plate; and first means carried on the base structure, the first means having a contact portion which contacts a lower surface of the screen plate to scrape off any foreign things from the lower surface when the base structure is moved in a direction parallel with a major surface of the screen plate.

According to a second aspect of the present invention, there is provided a cleaning device for cleaning a screen plate used in a screen printing, which comprises housing; a shaft rotatably disposed in the housing, the shaft having a plurality of cleaning blades disposed thereabout; first means for rotating the shaft so that tops of the cleaning blades hit a lower surface of the screen plate; and second means for supplying the cleaning blades with a solvent.

According to a third aspect of the present invent ion, there is provided a cleaning device for cleaning a screen plate used in a screen printing, which comprises a housing; a shaft rotatably disposed in the housing, the shaft having a plurality of cleaning blades disposed thereabout; first means for rotating the shaft so that tops of the cleaning blades hit a lower surface of the screen plate; cleaning rollers rotatably disposed on the housing in a manner to be pressed against the lower surface of the screen plate; a cleaning paper intimately disposed between each of the cleaning roller and the lower surface of the screen plate; second means for moving the cleaning paper along a given traveling path which includes the outer surfaces of the cleaning rollers; and third means for feeding the cleaning paper with a solvent. preferred features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic illustration of a screen cleaning device as described in GB-A-2 297 947:: Fig. 2 is an enlarged perspective view of part of the cleaning device of Fig. 1; Fig. 3 is a schematic view of a drive mechanism employed in the cleaning device of Fig. 1; Fig. 4 is a perspective view of a screen cleaning device of a first embodiment of the present invention; Fig. 5 is a schematically illustrated sectional view of the cleaning device of Fig. 4; Figs. 6A and 6B are sketches of a screen cleaning device of a second embodiment of the invention; Fig. 7 is a view similar to Fig. 6B, but showing a third embodiment of the invention; Fig. 8 is a sketch showing an essential portion of a screen cleaning device of a fifth embodiment of the invention; Fig. 9 is a perspective view of the screen cleaning device of the embodiment of Figs. 6A and 6B;; Fig. 10 is an enlarged perspective of one cleaning roller employed in the second embodiment; and Fig. 11 is an enlarged side view of a drive mechanism employed in the second embodiment.

Referring to Figs. 1 to 3 of the drawings, particularly Fig. 1 there is shown a screen cleaning device 10A which is not an embodiment of the present invention.

As is understood from Fig. 1, the device lOA is arranged below a screen plate 'S" of a screen print type printer. That is, as will become apparent as the description proceeds, when, after completion of printing a given circuit pattern on an insulating base board (not shown), the base board thus printed is removed from the printing work position, the cleaning device 10A is lifted up to the illustrated working position. At this working position, first, second and third cleaning blades 12a, 12b and 12c of the cleaning device l0A are pressed at their tops against a lower surface of the screen plate "S", as shown.

The first and second blades 12a and 12b have a wet cleaning paper 14 put on the tops thereof, while the third blade 12c has no cleaning paper 14 put thereon. The cleaning device l0A is then horizontally moved forward and backward causing the tops of the cleaning blades, 12b and 12c to run forward and backward on the lower surface of the screen plate "S". More specifically, the sliding movement of the first and second cleaning blades 12a and 12b on the screen plate "S" is carried out with the wet cleaning paper 14 put therebetween. The cleaning paper 14 is automatically fed to the tops of the first and second cleaning blades 12a and 12b and automatically fed with a cleaning solvent which can dissolve an ink residue left on the screen plate "S". That is, when the cleaning action is repeated by certain times, the cleaning paper 14 on the first and second cleaning blades 12a and 12b is somewhat shifted putting a new clean part of the cleaning paper 14 onto the tops of the cleaning blades 12a and 12b and then the new clean part is fed with the cleaning solvent.

Thus, during the sliding movement, the first and second cleaning blades 12a and 12b wipe away the ink residue on the screen plate "S" with the aid of the solvent, while the third cleaning blade 12c scrapes off the ink residue. As will be described hereinafter, each of the first and second cleaning blades 12a and 12b is of a double blade type which has two thin blade strips.

As is seen from Fig. 1, the cleaning device 10A comprises a rectangular base board 16. It is to be noted that the base board 16 extends in the direction perpendicular to the sheet of Fig. 1.

On the base board 16, there are disposed first and second rectangular housings 18 and 20. As shown, the first rectangular housing 18 has an angularly depressed portion 18a at one lower side thereof. The first housing 18 is detachably mounted on the base board 16, while the second housing 20 is securely mounted on the base board 16. That is, when needed, the first housing 18 can be easily dismantled from the base board 16 with simple work.

Within the first housing 18, there are rotatably installed a paper feeding roller 22 and a paper take-up roller 24 whose parallel axes extend along the longitudinal axis of the first housing 18. The cleaning paper 14 is wound on the paper feeding roller 22 and fed therefrom to the take-up roller 24 in such a manner as will be described hereinafter.

Rotatably installed near the paper feeding roller 22 is a press roller 26 which is biased rightward in Fig. 1 by a spring 28. The press roller 26 is pressed against a drive roller 30 which is rotatably installed in the second housing 20, as shown. The drive roller 30 has a cylindrical outer surface covered with a rubber skin. For achieving the abutment between the press and drive rollers 26 and 30, an aperture 32 is formed in a wall of the second housing 20 as shown. The drive roller 30 is driven in the direction of the arrow by a drive mechanism (shown in Fig. 3) which will be described hereinafter.

The first housing 18 is formed at an upper wall with an elongate aperture 18b. An elongate box 34 is installed in the first housing 18 in such a manner that the interior of the box 34 is exposed to the elongate aperture 18b. It is to be noted that the box 34 is detachably connected to the first housing 18 by means of a so-called one touch connector. That is, when needed, the box 34 can be easily dismantled from the first housing 18. An elongate guide structure 36 is disposed in the elongate box 34 to define two blade holder supporting spaces (no numerals).

Within the two spaces, there are slidably installed two blade holders 38a and 38b which respectively hold the first and second blades 12a and 12b. A spring 40a or 40b is disposed in each of the spaces for biasing the blade holder 38a or 38b outward, that is, upward in Fig. 1. A balance roller 42 is arranged between the two blade holders 38a and 38b.

As shown, the cleaning paper 14 drawn from the paper feeding roller 22 is intimately sandwiched between the press and drive rollers 26 and 30, and then to the top of the second cleaning blade 18b, to the balance roller 42, to the top of the first cleaning blade 12a and then to the paper take-up roller 24. It is thus to be noted that when the drive roller 30 is rotated in the direction of the arrow, the cleaning paper 14 is driven to the second cleaning blade 12b from the paper feeding roller 22. The drive roller 30 is controlled to drive the cleaning paper 14 by several millimeters for each rotation.

For driving the paper take-up roller 24 and the balance roller 42 in the directions of the respective arrows, first and second drive belts 44 and 46 are employed which are illustrated by phantom lines in the drawing. The first drive belt 44 is operatively put on a shaft of the press roller 26, a shaft of the paper take-up roller 24 and four guide rollers 48, 50, 52 and 54, while, the second drive belt 46 is operatively put on the guide roller 50 and a shaft of the balance roller 42. That is, when, due to rotation of the drive roller 30, the press roller 26 is rotated, the first and second drive belts 44 and 46 are driven to rotate the paper take-up roller 24 and the balance roller 42, which causes the cleaning paper 44 to be taken up by the take-up roller 24.

As will be described in detail hereinafter, the traveling of the cleaning paper 14 along the given path is intermittently carried out.

As shown, the second housing 20 is formed at an upper wall with an elongate aperture 20a. An elongate box 56 is installed in the second housing 20 in such a manner that the interior of the box 56 is exposed to the aperture 20a. It is to be noted that similar to the case of the above-mentioned box 34, the box 56 is detachably connected to the second housing 20. Within the box 56, there is slidably installed a blade holder 58 which holds the third cleaning blade 12c. A spring 60 is disposed in the box 56 to bias the blade holder 58 outward, that is, upward in Fig. 1. The second housing 20 is formed at a lower portion with a tube connector 20b to which a tube (not shown) extending from a suction pump (not shown) is connected.That is, under operation of the vacuum pump, the ink residue scraped off by the third cleaning blade 12c is instantly conveyed to the outside through the interior of the second housing 20.

As is seen from Fig. 2, the first and second cleaning blades 12a and 12b comprise each two thin blade strips 12a-1 and 12a-2 (or 12b-1 and 12b-2) which are arranged to leave a thin clearance therebetween.

Each thin blade strip is constructed of a steel. The thickness of the strip is about 100 to 200 pin. Preferably, the strip is projected from the blade holder 38a or 38b by about 5 to 15 'rim.

The thin clearance defined between the two thin blade strips is communicated through a hollow of the blade holder 38a or 38b and a tube 62 or 64 to a solvent supplier (not shown). In the illustrated embodiment, the tubes 62 and 64 from the two blade holders 38a and 38b are connected to a common pipe 66 which extends to the solvent supplier. The common pipe 66 is equipped with an electromagnetic valve 68 for selectively opening and closing a solvent flowing passage defined therein. Denoted by numerals 70 and 72 are connectors through which the tubes 62 and 64 are detachably connected to the hollows of the blade holders 38a and 38b.Thus, when, under operation of the solvent supplier, the electromagnetic valve 68 is energized to open the solvent flowing passage, a certain amount of solvent is injected to the outside from the respective clearances of the first and second cleaning blades 12a and 12b. Thus, when such injection is carried out with the cleaning paper 14 put on the tops of the blades 12a and 12b, =e cleaning paper 14 becomes wet with the solvent.

Referring to Fig. 3, there is shown the drive mechanism which drives the afore-mentioned drive roller 30. It is to be noted that the illustration of Fig. 3 is taken from the back side of the illustration of the cleaning device 10A of Fig. 1.

The drive mechanism comprises a first pneumatic cylinder 74 which is mounted on a slider (not shown). The slider is constructed to move forward and rearward together with the cylinder 74. The cylinder 74 has a piston rod 74a whose top end is connected to the base board 16 of the cleaning device 10A. That is, when one work chamber of the cylinder 74 is charged with a compressed air, the piston rod 74a pushes up the cleaning device 10A to the above-mentioned work position (viz., the position shown in Fig. 1). A shaft of the drive roller 30 is denoted by numeral 30a. A drive lever 76 is connected at one end to the shaft 30a through a one-way clutch 78. The other end of the drive lever 76 is pivotally connected through a pin 79 to one end of an L-shaped rod 80 whose other end is pivotally connected to cylinder 74.Thus, it will be appreciated that when the piston rod 74a is projected upward, the drive lever 76 is pivoted downward (viz., in a clockwise direction in Fig. 3) about the axis of the shaft 30a of the drive roller 30. However, due to function of the one-way clutch 78, such downward pivoting of the drive lever 76 does not induce a rotation of the drive roller 30 in the paper driving direction.

When, due to energization of the other work chamber of the cylinder 74, the piston rod 74a is drawn into the cylinder 74, the drive lever 76 is pivoted upward (that is, in a counterclockwise direction in Fig. 3). Due to function of the one-way clutch 78, such pivoting movement of the drive lever 76 induces a slight rotation of the drive roller 30 in the paper driving direction.

The drive lever 76 is formed with a plurality of small openings 76a to 76d with which the pin 79 is engageable. That is, by connecting the Lshaped rod 80 to one of such openings 76a to 76d through the pin 79, the rotation pitch of the drive roller 30 can be changed or controlled.

In the following, operation of the cleaning device 10A will be described with reference to Figs. 1, 2 and 3. For ease of understanding, the description will be commenced with respect to a condition wherein the printing operation by the squeegee has just finished. Until this time, the cleaning device 10A takes a rest condition. That is, in this rest condition, the slider on which the cleaning device 10A is mounted takes a rear rest position and the piston rod 74a of the pneumatic cylinder 74 is kept pulled down causing the cleaning device lOA to take a lower rest position.

Upon finishing of the printing operation, the base board thus printed is removed from the screen plate "S". Then, the pneumatic cylinder 74 is energized to push up the cleaning device lOA to the work position as shown in Fig. 1. As has been described hereinabove, such upward movement does not induce the paper driving rotation of the drive roller 30. Thus, the cleaning paper 14 is kept stationary. Due to the reason which will be described hereinafter, the portions of the cleaning paper 14 which have been put on the tops of the first and second cleaning blades 12a and 12b are new clean portions of the paper 14. When the cleaning device l0A comes up to the work position, the electromagnetic valve 68 is energized to open its passage for a given short time.With this, a certain amount of solvent is injected from the cleaning blades 12a and 12b to wet the cleaning paper 14 kept put on the blades. Then, the slider is energized to move forward and backward together with the cleaning device 10A mounted thereon. Thus, ink residue on the screen plate "S" is wiped off by the wet cleaning paper 14 on the first and second cleaning blades 12a and 12b and scraped off by the third cleaning blade 12c. During this one round trip of the cleaning device 10A, the suction pump connected to the interior of the second housing 20 is kept energized. Thus, the ink residue scraped off by the third cleaning blade 12c is instantly discharged to the outside through the interior of the second housing 20.

When the slider comes back to the original position, the pneumatic cylinder 74 is energized to pull down the cleaning device lOA from the working position. Due to this pull down movement of the cleaning device lOA, the drive lever 76 connected to the shaft 30a of the drive roller 30 is pivoted upward. This upward pivoting of the drive lever 76 induces a slight rotation of the drive roller 30 in the paper driving direction, as has been described hereinafore. Thus, the stained portions of the cleaning paper 14 which have been put on the tops of the first and second cleaning blades 12a and 12b are replaced with new clean portions of the cleaning paper 14, and the stained portions of the paper 14 are directed toward and finally wound on the paper take-up roller 24.By adjusting the rotation pitch of the drive roller 30 and/or the distance of traveling path between the first and second cleaning blades 12a and 12b, the first cleaning blade 12a is prevented from putting thereon a stained portion of the cleaning paper 14 which has been put on the second cleaning blade 12b.

Upon completion of the above-mentioned operation, the cleaning device lOA takes the above-mentioned reSt condition or stand-by position for a subsequent cleaning operation.

Referring to Figs. 4 and 5, there is shown a screen cleaning device lOF which is a first embodiment of the present invention.

The cleaning device 10F comprises a rectangular housing 170 which is formed at its upper wall with a rectangular opening I'iOa. Within the housing 170, there is installed a shaft 172 whose axial ends are rotatably supported by longitudinally opposed walls of the housing 170. A plurality of cleaning blades 174 are disposed around the shaft 172 at evenly spaced intervals.

As shown in Fig. 5, the cleaning blades 174 are projected from the opening I'iOa of the housing 170 when brought to their upper positions.

As shown in Fig. 4, one axial end of the shaft 172 has an extended portion 1 72a exposed to the outside from the longitudinal wall of the housing 170. A pulley 1,6 is coaxially secured to the extended portion 172a to rotate therewith. A holder plate 158 is secured to the longitudinal wall of the housing 170 to mount thereon an electric motor 180. An output shaft (no numeral) of the motor 180 is equipped with a pulley 182. An endless belt 184 is operatively put on the two pulleys 182 and 176. Thus, when the electric motor 180 is energized, the blade-mounted shaft 172 is rotated at a given speed.

As shown in Fig. 5, within the housing 1 /O, there is installed a pipe 186 of rectangular cross section below the blade-mounted shaft 172. Two resiliently deformable strips 188a and 188b are mounted on the pipe 186 in such a manner that a thin clearance defined between the strips 188a and 188b is communicated with the interior of the pipe 186. As shown, the two strips 188a and 188b have tops contactable with the cleaning blades 174 of the shaft 172. A tube 190 extending from a solvent supplier (not shown) is connected to the pipe 186 to feed the interior of the pipe 186 with a solvent.

Designated by numeral 20b is a tube connector to which a tube (not sho"','n) extending from a suction pump is connected.

In the following, operation of the cleaning device 10F will be described. Although not shown in Figs. 4 and 5, the above-described pneumatic cylinder 74 (see Fig. 3) mounted on a slider is also employed in this first embodiment.

When the cleaning device lOF is lifted up to the work position, the suction pump is energized and the electric motor 180 is energized to run the blade-mounted shaft 172. At the same time, the solvent supplier is energized to inject solvent from the clearance of the strips 188a and 188b.

Thus, the cleaning blades 1,4 scrape off ink residue left on the screen plate "S" at high speed. During rotation of the blade-mounted shaft 172. the cleaning blades 174 hit the strips 188a and 188b, and thus. any ink residue having been left on the cleaning blades 174 is scattered into the interior of the housing 170. Separation of the ink residue from the cleaning blades 1,4 is promoted by the solvent supplied thereto from the clearance of the strips 188a and 188b. The ink residue is then discharged to the outside of the housing 170 due to the work of the suction pump.

If desired, the following modification may be employed in this first embodiment lOF. That is, in the modification, a cleaning paper driven by a suitable drive mechanism is put on the tops of the strips 188a and 188b.

Referring to Figs. 6 A, 6B, 9, 10 and 11, there is shown a screen cleaning device lOG which is a second embodiment of the present invention.

As is well understood from Fig. 6 A, the cleaning device lOG comprises a container 192.

In an upper portion of the container 192, there is rotatably disposed a blade-mounted shaft 172.

A resiliently deformable strip 194 held by a blade holder 194a is installed in the container 192 below the shaft 172. Two cleaning rollers 195a and 195b are arranged at the upper portion of the container 192, each cleaning roller 195a or 195b being biased upward by springs 199a and 199b in such a manner as is shown in Fig. lO.

Two larger guide rollers 196a and 196b (see Fig.

6 A) and two smaller guide rollers 198a and 198b are rotatably disposed in a lower portion of the interior of the container 192, as shown. An endless cleaning paper 14 is put on these six rollers in the illustrated manner. A cleaning solvent "L" is contained in the container 192 to wet the cleaning paper 14. A tube 200 extending from a solvent supplier (not shown) is connected to a lower portion of the container 192.

As is seen from Fig. 6B, the blade-mounted shaft 172 and the two larger guide rollers 196a and 196b have extended portions exposed to the outside of the container 192. The extended portions have respective gears or pulleys 202, 204 and 206 secured thereto. An endless toothed belt 208 is put on these three gears 202, 204 and 206 in the illustrated manner. Thus, when, for example, the gear 202 is rotated, blade-mounted shaft 172 is rotated and the cleaning paper 14 is driven in a certain direction with the solvent absorbed therein.

As is seen from Figs. 9 and , the extended portion on which the gear 202 is disposed is driven by a drive mechanism "D" powered by an electric motor 180.

As is best seen from Fig. 11 , the drive mechanism "D" comprises a first gear 310 disposed on the extended portion of the blade-mounted shaft 172. A second gear 312 disposed on a first shaft 314 is meshed with the first gear 310. The first shaft 314 is rotatably supported by supporting walls 313 and 315. A third gear 316 disposed on the first shaft 314 is meshed with a fourth gear 318 which is disposed on a second shaft 320. The second shaft 320 is rotatably disposed by the supporting wall 315 and has a fifth gear 322 disposed thereon.

As is seen from Fig. 9., the fifth gear 322 is meshed with a sixth gear 324 rotatably supported by the walls 315 and 326. The sixth gear 324 is meshed with a seventh gear 328 which is disposed on an output shaft of the electric motor 180. The motor l80 is mounted on a support plate 330 secured to the container 192. Thus, when the electric motor 180 is energized, the power produced by the motor 180 is transmitted to the gear 202 of the blade-mounted shaft 172 through a gear train of the above-mentioned gears.

Referring to Fig. 7 , there is shown a screen cleaning device 10H of a third embodiment of the present invention.

Since this embodiment lOH is similar in construction to the above-mentioned second embodiment lOG, only different portions will be described in the following.

That is, in this embodiment 10H, in place of the solvent "L" contained in the container 192 which is adapted in the second embodiment lOG, two solvent injection nozzles 210 and 212 are employed, which are arranged at front and rear positions of the container 192 to inject cleaning solvent to the lower surface of the screen plate "S". These nozzles 210 and 212 are connected to a solvent supplier (not sown) through an electromagnetic valve 214. Thus, when the valve 214 is energized to open its passage, a suitable amount of solvent is injected to the screen plate "S" from the nozzles 210 and 212.

Referring to Fig. 8 , there is shown a screen cleaning device 10I of a fourth embodiment of the present invention, which is a modification of the above-mentioned second embodiment lOG (see Fig. 6A).

In this modification 10I, two cleaning blades 12a and 12b are employed in place of the cleaning rollers 195a and 195b of the second embodiment lOG. Each cleaning blade 12a or 12b includes two thin blade strips 12a-1 and 12a-2 (or 12b-1 and 12b-2) between which a thin clearance is defined, like in case of the embodiment lOA (see Fig. 2). The cleaning blades 12a and 12b are held by respective blade holders 38a and 38b which are biased upward by respective springs 40a and 40b. A balance roller 42 is arranged between the two cleaning blades 12a and 12b. The thin clearance defined by each cleaning blade 12a or 12b is communicated through a hollow of the blade holder 38a or 38b to a solvent supplier (not shown).The cleaning paper 14 is put on the two cleaning blades 12a and 12b and the balance roller 42 in the illustrated manner.

Attention is directed to our co-pending application No. 9602823.8 (GB-A-2 297 947) from which this application has been divided.

The parent application claims a cleaning device for cleaning a screen plate used in screen printing, comprising: a supporting structure capable of being positioned below the screen plate following the completion of a printing operation upon a base board upon the screen plate and the removal of the base board from the screen plate, the supporting structure being movable below the screen plate in a given direction parallel with the lower surface of the screen plate; at least one press member carried on the supporting structure; and a cleaning web driving mechanism for moving a cleaning web along a path which includes the top of the press member, so that. in use of the cleaning device, the cleaning web is intimately interposed between the top of the press member and the lower surface of the screen plate so as to scrape off foreign things from the said surface when the supporting structure is moved in the said given direction.

The parent application also claims a cleaning device for cleaning a screen plate used in screen printing, comprising: a housing; a shaft rotatably disposed in the housing, the shaft having a plurality of cleaning blades disposed thereabout; means for rotating the shaft so that tops of the cleaning blades hit a lower surface of the screen plate, in use; cleaning rollers rotatably disposed on the housing so as to be capable of being pressed against the lower surface of the screen plate: means for moving a cleaning web along a path which includes part of the outer surface of the cleaning rollers, the cleaning web being intimately interposed between each cleaning roller and the lower surface of the screen plate; and means for feeding the cleaning web with a solvent.

Claims (6)

CLAIMS:

1. A cleaning device for cleaning a screen plate used in screen printing, comprising: a housing; a shaft rotatably disposed in the housing, the shaft having a plurality of cleaning blades disposed thereabout; means for rotating the shaft so that tops of the cleaning blades hit a lower surface of the screen plate, in use; and means for supplying the cleaning blades with a solvent.

2. A cleaning device as claimed in claim 42, in which the shaft rotating means comprises: a pulley connected to the shaft; a motor having an output shaft; a pulley connected to the output shaft; and an endless belt operatively put on the said pulleys.

3 A cleaning device as claimed in claim 1 or 2, in which the solvent supplying means comprises: a pipe installed in the housing just below the said shaft, the interior of the pipe being connected with a solvent supplier; and two resiliently deformable strips mounted on the pipe in such a manner that a clearance defined between the strips is communicated with the interior of the pipe, the strips having tops contactable with the cleaning blades.

4. A cleaning device as claimed in any of claims 1 to 3, further comprising suction means by which foreign things in the housing are discharged to the outside.

5. A cleaning device substantially as described with reference to Figures 4 and 5 of the accompanying drawings.

6. A screen printing machine including a cleaning device according to any of the preceding claims.