Printhead pressure adjustment for a printing apparatus

Patent metadata

Field	Value
Publication number	US-2019389211-A1
Application number	US-201816014300-A
Country	US
Kind code	A1
Filing date	Jun 21, 2018
Priority date	Jun 21, 2018
Publication date	Dec 26, 2019
Grant date	—

Abstract

Provided herein is a printing apparatus that includes a printhead assembly and a plurality of printhead pressure load modules that are adjustable on a shaft of a printhead pressure load assembly and engaged with a printhead member. The printhead pressure load module has a hollow housing, a plunger member, and a rotary cam. The plunger member and the rotary cam are movably engaged in the hollow housing. The rotary cam includes a plurality of channel members defined at an outer surface. Each channel member has a depth that is different from a depth of an adjacent channel member. A movement of the plunger member inwardly through the hollow housing defines a position of the rotary cam along the longitudinal axis with respect to the hollow housing. Position change of the rotary cam defines a force that acts on a pressure contact member and adjusts a load on the printhead assembly.

First claim

1 . A printing apparatus comprising:
a printhead assembly extending a printhead width in a direction transverse to a web direction; a plurality of printhead pressure load modules adjustable on a shaft of a printhead pressure load assembly and engaged with a printhead member, the shaft extending in the direction transverse to the web direction, each of the plurality of printhead pressure load modules comprising:
a hollow housing having fixed flanges defined on an inner surface and extending along a longitudinal axis of the printhead pressure load module;
a plunger member, slidably mounted through a top end of the hollow housing, wherein the plunger member has a cap portion and leg portions, the leg portions extending along the longitudinal axis and movably positioned adjacent to the fixed flanges;
a rotary cam movably engaged in the hollow housing and coupled with the cap portion of the plunger member through a first biasing member, opposite ends of the biasing member being secured to a bottom surface of the cap portion and a top surface of the rotary cam, respectively, the rotary cam comprising a plurality of channel members defined at an outer surface of the rotary cam and extending from a top end of the rotary cam along the longitudinal axis, each channel member having a depth that is different from a depth of an adjacent channel member,
wherein a movement of the plunger member inwardly through the top end of the hollow housing and a resultant engagement of at least the fixed flanges with two diametrically opposite channel members having defined depths defines a position of the rotary cam along the longitudinal axis with respect to the top end of the hollow housing, and
a pressure contact member is positioned towards a bottom end of the hollow housing and engaged with a bottom end of cap portion of the rotary cam through a second biasing member such that a change in the position of the rotary cam defines a force that acts on the pressure contact member through the second biasing member and causes the pressure contact member to adjust a load on the printhead assembly engaged with the printhead pressure load module.

2 . The printing apparatus according to claim 1 , wherein the plurality of channel members comprises at least three pairs of channel members, each pair of the at least three pairs of channel members have identical channel members, equidistant from an axis of rotation of the rotary cam, and defined diametrically opposite to each other on the outer surface of the rotary cam.

3 . The printing apparatus according to claim 1 , wherein a periphery of each of the plurality of channel members is defined by one or more longitudinal surfaces and one or more chamfered surfaces, wherein a first portion of the periphery defines the depth of corresponding channel member.

4 . The printing apparatus according to claim 3 , wherein one of the one or more longitudinal surfaces in each channel member is a stopping longitudinal surface configured to stop a rotational movement of the rotary cam.

5 . The printing apparatus according to claim 3 , wherein at least one of the one or more chamfered surfaces in each channel member is defined along a helical path around the outer surface of the rotary cam that defines the depth of the corresponding channel member, wherein others of the one or more chamfered surfaces in each channel member extend from the top surface of the rotary cam to other longitudinal surface of the corresponding channel member.

6 . The printing apparatus according to claim 1 , wherein the at least three pairs of the plurality of channel members are engaged successively by the fixed flanges that defines the position of the rotary cam along the longitudinal axis with respect to the top end of the hollow housing, wherein the position of the rotary cam along the longitudinal axis defines a magnitude of the force that acts on the pressure contact member through the second biasing member.

7 . The printing apparatus according to claim 1 , wherein a longitudinal surface of a channel member is defined by an upper edge of a chamfered surface of a channel member of an axially backward channel member and a lower edge of a chamfered surface of the channel member, wherein in an instance when both the leg portions and the fixed flanges are engaged in the channel member, the longitudinal surface of the channel member is a stopping surface abutting the leg portion, wherein in an instance when the leg portion is withdrawn due to movement of the plunger member outwardly under an influence of the first biasing member, the longitudinal surface of the channel member acts as a stopping surface abutting the fixed flange.

8 . The printing apparatus according to claim 1 , wherein a top portion of each of the fixed flanges is extended as a circumferentially structured stop member defined on the inner surface of the hollow housing, and the ending portion is having a chamfered surface is configured to abut a chamfered surface of the rotary cam and move the rotary cam in a downward direction.

9 . The printing apparatus according to claim 1 , wherein the hollow housing includes a longitudinal window showing current position of the rotary cam.

10 . The printing apparatus according to claim 1 , wherein the printhead member is adjusted in one of a printing position or loading position, wherein a printhead bracket of the printhead member comprises a horizontal surface and an inclined surface.

11 . The printing apparatus according to claim 10 , wherein in an instance when the printing apparatus is in printing mode and the printhead member is adjusted in the printing position, the plurality of printhead pressure load modules are aligned vertically along the longitudinal axis and the pressure contact members are engaged with the horizontal surface of the printhead bracket.

12 . The printing apparatus according to claim 10 , wherein in an instance when the printing apparatus is in loading mode and the printhead member is adjusted in the loading position, the plurality of printhead pressure load modules rotate in reverse web direction around the shaft and the pressure contact members are slidably engaged with the inclined surface of the printhead bracket.

13 . A printhead pressure load module comprising:
a hollow housing having fixed flanges defined on an inner surface and extending along a longitudinal axis of the printhead pressure load module; a plunger member, slidably mounted through a top end of the hollow housing, wherein the plunger member has a cap portion and leg portions, the leg portions extending along the longitudinal axis and movably positioned adjacent to the fixed flanges; a rotary cam movably engaged in the hollow housing and coupled with an inner surface of the cap portion of the plunger member through a first biasing member secured to the cap portion, the rotary cam comprising a plurality of channel members defined at an outer surface of the rotary cam and extending from a top end of the rotary cam along the longitudinal axis, each channel member having a depth that is different from a depth of an adjacent channel member,
wherein a movement of the plunger member inwardly through the top end of the hollow housing and a resultant engagement of at least the fixed flanges with two diametrically opposite channel members having defined depths defines a position of the rotary cam along the longitudinal axis with respect to the top end of the hollow housing, and
a pressure contact member is positioned towards a bottom end of the hollow housing and engaged with a bottom end of a cap portion of the rotary cam through a second biasing member such that a change in the position of

Assignees

• Datamax Oneil Corp

Inventors

• Yap Yaw Horng
• Wong Chin Young
• Chua Ching Hong
• Lim Eng Hing

Classifications

• B41J2/145

  Arrangement thereof · CPC title

• B41J2/1433 Primary

  Structure of nozzle plates · CPC title

• B41J25/312 Primary

  with print pressure adjustment mechanisms, e.g. pressure-on-the paper mechanisms · CPC title