Patent ID: 12220929

DETAILED DESCRIPTION

A printing system comprises a printer body10, a print carriage12and a height adjustment apparatus14. The print carriage12may be mounted on the height adjustment apparatus14, as shown inFIG.1so that the height adjustment apparatus supports the print carriage12in use. The printer body10may comprise a platen over which print media advances and a rod16, shown inFIG.2, along which the print carriage12slides in use.FIG.2show a portion of the printing system with the print carriage12removed. As shown inFIG.2, the height adjustment apparatus14can be mounted to the rod16and the height adjustment apparatus14may be configured to slide along the rod16. The print carriage12may comprise a printhead and the print carriage12and height adjustment apparatus14may be configured to slide along the rod16in an axial direction in order to move the printhead over media that advances on the platen. The height adjustment apparatus14may be configured to adjust the height of the print carriage12relative to platen by moving the height of the print carriage relative12to the rod16.

As shown inFIGS.3aand3b, the height adjustment apparatus14for the print carriage12comprises a first support18for supporting the print carriage12and a moving mechanism configured to move the first support18.

The first support18comprises a first support surface20configured to slidingly engage a corresponding surface22of the print carriage12. The height of the first support surface20in a first direction A increases in a second direction B. For example, the first support surface20may be a sloped surface as shown inFIGS.3aand3b. The second direction B may be parallel to the axial direction of movement of the print carriage along the rod. The first direction A may be perpendicular to the second direction. Adjusting the height of the print carriage12may comprise moving the print carriage up in the first direction A or down, in a third direction C, opposite to the first direction A.

The moving mechanism is configured to move the first support18in the second direction B. When the first support18is moved in the second direction B, the print carriage surface22is configured to slide relative to the first support surface20to move the print carriage12down in the third direction C. When the first support18is moved in a fourth direction D, opposite to the second direction B, the print carriage12may be configured to slide relative to the first support surface20to move the print carriage12up in the first direction A. This may provide a simplified apparatus for adjusting height of a print carriage.

The height adjustment 14 apparatus may comprise a second support24. The second support24may comprise a second support surface26. The height of the second support surface24may increase in the fourth direction D and the first and second supports18,24may be separated in the second direction. The first support18may be configured to support a first end28of the print carriage12and the second support24may be configured to support a second end30of the print carriage12.

The moving mechanism may be configured to move the second support24in the second direction B and the fourth direction D, so that the first and second supports18,24move away from each other or towards each other. Adjusting the distance between the first and second supports18,24may cause the print carriage12to slide along the support surfaces22,26in the first and third directions A, C, thereby adjusting the height of the print carriage12. Moving the first and second supports18,24towards each other may cause the carriage12to move upwards as shown inFIG.3a, and moving the first and second supports18,24away from each other may cause the carriage12to move downwards, as shown inFIG.3b.

The moving mechanism may comprise a cam32. The cam32may be substantially tubular and may be mountable to the rod16as shown inFIG.2, such that in use, the cam is coaxially provided around the rod16. The cam32may be rotatable about the rod16. Rotation of the cam32may cause the first support18and second support24to move in the second direction B and fourth direction D.

The first and second supports18,24may be bushings and may be provided at either axial end of the cam32, as shown inFIGS.4aand4b. The bushings may be mountable to the rod16, such that in use, the bushings are coaxially provided around the rod16. The bushings may not be rotatable relative to the rod. For example, the bushings may comprise a planar surface34, as shown inFIGS.4aand4b, which may sit against a planar surface of the carriage, thereby preventing rotation of the bushing about the rod.

As shown inFIGS.5aand5b, the cam32may comprise an open region36along its longitudinal length, such that the cam may be removably mounted to the rod. Similarly, as shown inFIGS.4aand4b, the bushings may comprise an open region38along their longitudinal length, such that the bushings may be removably mounted to the rod with the cam32.

As shown in more detail inFIGS.4aand4b, the first end of the cam32may comprise an engagement surface40, which may be configured to engage a corresponding engagement surface42of the support. The cam engagement surface40may be provided at the axial end of the cam32and may be configured to face the engagement surface42of the support18. The second end of the cam32may also comprise an engagement surface, which may be configured to engage a corresponding engagement surface of the second support24.

The cam engagement surface40may comprise a toothed structure. The support engagement surface42may comprise a correspondingly toothed structure. When the cam32is provided in a first rotational position, shown inFIG.4a, the cam32may be coupled to the support18by the seating of the toothed structures of the cam engagement surface40and the support engagement surface42. When the cam32is rotated in a first rotational direction to a second rotational position, shown inFIG.4b, the cam32may be configured to uncouple from the support18by separating the toothed structures of the first cam engagement surface40and the support surface. The separating of the toothed structures may cause the toothed structure of the first cam engagement surface40to push against the toothed structure of the support engagement surface42, thereby pushing the support18in the second direction B.

When the cam32is rotated in an opposite rotational direction to the first rotational position, the cam may32be configured to recouple to the support18. The support18may be biased in the fourth direction D towards the cam32, such when the cam32is rotated to the first rotational position, the support engagement surface42is biased towards the cam engagement surface40of the cam32and the support18recouples to the cam32.

In an example, the height adjustment apparatus14may comprise one or more springs44configured to bias the supports18,24towards the cam32, as shown inFIGS.3aand3b. The one or more springs44may be mounted between an end of the supports18,24and plates46attached to the carriage that are provided around the rod16and spaced apart from the axial end of the supports18,24. The one or more springs44may push against the axial end of the supports18,24to push the supports towards the cam32.

The cam32may be pivotably connected to a follower48. The follower48may be configured to move up and down in the first and third directions A, C. Movement of the follower48in the first direction and third directions A, C may cause the cam32to rotate between the first rotational position and the second rotational position, as shown inFIGS.5aand5b.

As shown inFIG.5a, when the follower48is moved to an upper position, the cam32may be rotated to the first rotation position, wherein the cam32couples to the supports18,24. The print carriage12may thereby be provided at a first height above the platen.

When the follower48is moved to a lower position, as shown inFIG.5b, the cam32may be rotated to the second rotation position, wherein the supports18,24uncouple from the cam32. The print carriage12may thereby be provided at a second height above the platen, wherein the first height is greater than the second height.

The height adjustment apparatus14may be configured to facilitate the adjustment of the height of the follower48, in order to adjust the height of the print carriage12. The height adjustment apparatus may be configured to adjust the height of the print carriage12to be used at discrete heights, for example to adjust the height of the print carriage12between two different heights. The height adjustment apparatus may be configured to adjust the height of the carriage by less than 1 mm, for example 0.2-0.5 mm and preferably by 0.3 mm

The printing system may comprise a maze50for adjusting the height of the follower48, as shown inFIGS.5and6. The maze50may be fixed to the printer body10. The maze50may be configured to receive a pin52of the follower48.

In an example, the maze50provides a path P for moving the follower between upper and lower positions. The maze50may comprise an upper opening54and a lower opening58, and the path58may connect the upper and lower openings. The lower opening56may be on a first side of the maze50and the upper opening54may be on a second side of the maze50in the second direction B and a ramp58between the upper and lower openings may form the path. When the follower48is in the upper position and the carriage12moves in the second direction B, the pin52may enter the maze at an upper opening54. As the carriage continues to move in the second direction B, the pin52may follow the path down towards the lower opening56. The pin may leave the maze by the lower opening56, and so the follower may then be provided at the lower position.

Similarly, when the follower48is in the lower position, and the pin52enters the maze50at the lower opening56, movement of the carriage12in the fourth direction D may cause the pin52to move along the path P towards the upper opening54. The pin52may leave the maze by the upper opening54and so the follower48may then be provided at the upper position.

The follower48is pivotably attached to the cam32, which forms part of the height adjustment apparatus14that supports the printer carriage12. Movement of the printer carriage in the axial direction of the rod may cause the follower to move left or right in the maze. Movement of the carriage12along the rod16may therefore cause the adjustment of the height of the carriage, and a further motorized part to adjust the height of the carriage is not required.

The maze50may be movable between an active position and a passive position. The printing system may comprise a controller configured to move the maze towards or away from the carriage to move the maze between the active and passive positions.

In the active position, as shown inFIGS.5aand5b, movement of the carriage12towards the maze50in the second or fourth directions may cause the pin52to engage an opening54,56in the maze. In the passive position, as shown inFIG.7, the maze50may be retracted away from the carriage12into the printer body10, so that when the follower moves in the second or fourth directions, the follower48moves over the maze50without the pin52entering the maze50. The controller may be configured to move the maze50into the active position when it is desired to change the height of the carriage12. When the height of the carriage12is adjusted, the controller may then move the maze50into the passive position, so that movement of the carriage12along the rod16does not cause the pin48to enter the maze.

An example method of adjusting a height of a print carriage relative to a print surface comprises moving a follower in a maze between a first position and a second position, wherein a height of the second position in a first direction is greater than the height of the first position, wherein the follower is pivotably coupled to a cam and wherein movement of the follower between the first height position and the second height position causes rotation of a cam. Rotating the cam causes movement of a print carriage support in a second direction perpendicular to the first direction, and wherein movement of the support in the second direction causes movement of the print carriage in a first direction, thereby adjusting the height of the carriage. The method may comprise moving the maze from a passive position to an active position, to allow the follower to enter the maze.

Examples described herein may provide a simplified apparatus for adjusting a height of a print carriage, because the apparatus utilises the mechanical movement of supports and does not require motors, gears or specific software for adjusting the height. The adjustment of the height is caused by the movement of the carriage and adjustment apparatus along the rod, and therefore utilises the same motorised movement as in a printing operation wherein the print carriage is moved along the rod. The apparatus may have high repeatability, because it does not rely on additional motors for adjusting the height, but instead uses mechanical movement of supports based on a rotation of a cam.

If a print carriage is formed of two pieces, wherein one piece, for example a sub-carriage holding the print head, moves relative to a second piece, then the carriage could experience instability, which can affect performance. Such a carriage could also be expensive to manufacture, and time-consuming and expensive to repair or service. Examples described herein may provide means for adjusting a height of a carriage which may not depend on the shape of the carriage and wherein the carriage may be formed of one piece and may be moved relative to the printer body by the height adjustment apparatus. This may improve the performance and stability of the height adjustment. Examples described herein may provide a height adjustment apparatus that is low-cost and easy to repair or service.

In an example, the maze and follower may be removed to provide a printing system in which the carriage remains at only one height, but which implements the remaining components of the height adjustment apparatus to allow the printing system to be removably mounted to the printer body. This may improve manufacturing processes, because the printer body, print carriage and most of the height adjustment apparatus components can be used in manufacturing printing systems in which height may be adjusted, and printing systems in which height is not adjusted.