Screen printer and screen printing method

Patent metadata

Field	Value
Publication number	US-10889103-B2
Application number	US-201616085751-A
Country	US
Kind code	B2
Filing date	Mar 24, 2016
Priority date	Mar 24, 2016
Publication date	Jan 12, 2021
Grant date	Jan 12, 2021

Abstract

Screen printer 10 is for screen printing solder paste 13 loaded on an upper surface of stencil 12 onto board S using one of first and second squeegees 71 and 72. Screen printer 10 is provided with a stencil frame holding rail that holds stencil frame 12a of stencil 12, pair of board holding members 36 and 38 that hold board S, raising and lowering table 16 that raises and lowers board holding members 36 and 38, and pair of stencil supporting members 50 and 52 that support stencil 12 from below at a portion outside a printing region of stencil 12 used for screen printing. Stencil supporting members 50 and 52 are provided independently from raising and lowering table 16. Therefore, the load applied to raising and lowering table 16 is reduced. Also, there is increased design freedom with respect to members and the like loaded on raising and lowering table 16.

First claim

The invention claimed is:

1. A screen printer for screen printing a viscous fluid loaded on an upper surface of a stencil using a squeegee, the screen printer comprising:
a stencil edge section holding member configured to hold an edge section of the stencil;
a board holding member configured to hold a board;
a board holding member raising and lowering device configured to raise and lower the board holding member to and from a printing position set at a specified height for screen printing and a lower position that is lower than the printing position;
a stencil supporting member provided independently from the board holding raising and lowering device and configured to support from below a portion of the stencil outside of a printing region of the stencil that is used when performing screen printing, the edge section of the stencil being held by the stencil edge section holding member;
a squeegee raising and lowering device configured to raise and lower the squeegee to and from a contact position at which the squeegee contacts the upper surface of the stencil of which the edge section is held by a stencil edge holding member and a separation position that is higher than the contact position; and
a control device configured to control the board holding member raising and lowering device and the squeegee raising and lowering device such that the squeegee arrives at the contact position before the board holding member holding the board is raised to the printing position in a screen printing preparation phase.

2. The screen printer of claim 1 , wherein
the contact position is set directly on a support surface of the stencil supporting member.

3. The screen printer of claim 1 , further including
an imaging device provided to move below the stencil in a direction parallel to the stencil and configured to image a stencil reference section and a board reference section used for alignment provided respectively on the printing region of the stencil and the board, and
a control means configured to control the board holding member raising and lowering device and the imaging device such that the imaging device images the stencil reference section and the board reference section in the screen printing preparation phase after making a gap between the lower surface of the stencil and the board held by the board holding member such that the imaging device can pass through the gap.

4. The screen printer of claim 1 , further including
a negative pressure device configured to supply negative pressure to a negative pressure suction surface that supports a lower surface of the stencil among the stencil supporting member,
a stencil supporting member moving device configured to move the stencil supporting member in a direction parallel to the stencil, and
a control device configured to control the negative pressure device and the stencil supporting member moving device such that, when the board holding member holding the board is at a cleaning position that is lower than the printing position, the stencil supporting member is moved in the direction parallel to the stencil while negative pressure is supplied to the negative pressure suction surface such that the lower surface of the stencil is sucked to the negative pressure suction surface.

5. The screen printer of claim 4 , wherein
the stencil supporting member is provided as a pair to sandwich the printing region, and the stencil supporting member moving device moves at least one of the pair of the stencil supporting members in the direction parallel to the stencil.

6. A screen printing method for screen printing a viscous fluid loaded on an upper surface of a stencil using a squeegee, the screen printing method comprising:
(a) a step of holding a board using a board holding member;
(b) a step of raising the board holding member using a board holding member raising and lowering device to a printing position set at a specified height for screen printing,
during a screen printing preparation phase that is before the step (b), causing the squeegee to reach a contact position from a separation position that is higher than the contact position using a squeegee raising and lowering device to contact the upper surface of the stencil when a portion of the stencil outside of a printing region of the stencil that is used for screen printing is supported from below by a stencil supporting member provided separately to the board holding member raising and lowering device and an edge section of the stencil is held by a stencil edge holding member, and
controlling the board holding member raising and lowering device and the squeegee raising and lowering device such that the squeegee arrives at the contact position before the board holding member holding the board is raised to the printing position in a screen printing preparation phase.

7. A screen printing method for screen printing a viscous fluid loaded on an upper surface of a stencil using a squeegee, the screen printing method comprising:
(a) a step of holding a board using a board holding member;
(b) a step of raising the board holding member using a board holding member raising and lowering device to a printing position set at a specified height for screen printing;
(c) a step of raising and lowering the squeegee using a squeegee raising and lowering device to and from a contact position at which the squeegee contacts the upper surface of the stencil of which the edge section is held by a stencil edge holding member and a separation position that is higher than the contact position,
during a screen printing preparation phase that is after the step (a) and before the step (b), when a portion of the stencil outside of a printing region of the stencil that is used when performing screen printing is supported from below by a stencil supporting member provided separately from the board holding member raising and lowering device, using an imaging device to image a stencil reference section and a board reference section used for alignment provided respectively on the printing region of the stencil and the board after making a gap between a lower surface of the stencil and the board held by the board holding member such that the imaging device can pass through the gap, and
controlling the board holding member raising and lowering device and the squeegee raising and lowering device such that the squeegee arrives at the contact position before the board holding member holding the board is raised to the printing position in a screen printing preparation phase.

8. A screen printing method for screen printing a viscous fluid loaded on an upper surface of a stencil using a squeegee, the screen printing method comprising:
(a) a step of holding a board using a board holding member;
(b) a step of performing screen printing in a state with a portion of the stencil outside of a printing region of the stencil that is used when performing screen printing being supported from below the stencil using a negative pressure suction surface of a stencil supporting member that is provided separately from a board holding member raising and lowering device and the board holding member raised to a printing position set at a specified height for screen printing using the board holding member raising and lowering device;
(c) a step of performing cleaning by moving the stencil holding member in a direction parallel to the stencil after the board holding member has been lowered to a cleaning position that is lower than the printing position and while supplying negative pressure to the negative pressure suction surface such that the lower surface of the stencil is sucked to the negative pressure suction surface;
(d) a step of raising and lowering the squeegee using a squeegee raising and lowering dev

Assignees

• Fuji Corp

Inventors

• Kondo Takeshi

Classifications

• B41F15/36 Primary

  flat · CPC title

• B41F15/26

  for articles with flat surfaces · CPC title

• B41P2235/27

  Suction devices · CPC title

• B41P2215/112

  with means for displacing the frame · CPC title

• B41F15/423

  Driving means for reciprocating squeegees · CPC title