End-of-travel focus shift in an optical image scanner

1. An optical image scanner comprising:

a platen;

a stop member at a first end-of-travel position; and

an optical head comprising a ramped surface such that when the optical head engages the stop member the distance between the optical head and the platen is adjusted.

2. The optical image scanner of claim 1 , wherein the stop member is positioned below a lower surface of the platen.

3. The optical image scanner of claim 2 , wherein the optical head further comprises:

a housing;

a slide member having a top portion extending from the housing and engaging the lower surface of the platen: and

an adjustment member comprising an interior portion having the ramped surface and an end portion extending from a first side of the housing toward the stop member;

wherein the ramped surface engages a lower portion of the slide member such that when the optical head is translated toward a first end-of-travel position the end portion engages the stop member and the slide member is guided along the ramped surface.

4. The optical image scanner of claim 3 , wherein the adjustment member comprises a push-rod.

5. The optical image scanner of claim 3 , wherein the optical head is spring-loaded such that the slide member is held against the platen.

6. The optical image scanner of claim 3 , wherein the slide member comprises a slide bushing.

7. The optical image scanner of claim 3 , wherein the top portion of the slide member comprises a flat surface that engages the lower surface of the platen.

8. The optical image scanner of claim 3 , wherein the lower portion of the slide member engages the ramped surface.

9. The optical image scanner of claim 3 , wherein the slide member is guided up the ramped surface to increase the distance between the optical head and the platen.

10. The optical image scanner of claim 3 , further comprising a second stop member positioned below a lower surface of the platen at a second end-of-travel position.

11. The optical image scanner of claim 10 , wherein the adjustment member further comprises a second end portion extending from a second side of the housing toward the second stop member.

12. The optical image scanner of claim 3 , wherein the slide member is guided down the ramped surface to decrease the distance between the optical head and the platen.

13. A method of adjusting the location of an object plane above a platen to be scanned by an optical head, the method comprising:

translating the optical head such that a slide member is guided along a ramped surface to adjust the distance between the optical head and the platen;

translating the optical head toward a first end-of-travel position; and

engaging an adjustment member with a stop member located at the first end-of-travel position such that the adjustment member is no longer translated.

14. A method of adjusting the location of an object plane above a platen to be scanned by an optical head, the method comprising:

translating the optical head such that a slide member is guided along a ramped surface to adjust the distance between the optical head and the platen;

wherein the translating further comprises translating the optical head such that the slide member is guided down the ramped surface to decrease the distance between the optical head and the platen.

15. A method of adjusting the location of an object plane above a platen to be scanned by an optical head, the method comprising:

translating the optical head such that a slide member is guided along a ramped surface to adjust the distance between the optical head and the platen;

wherein the translating the optical head comprises further comprising translating the optical head such that the slide member is guided up the ramped surface to increase the distance between the optical head and the platen.

16. The method of claim 15 , further comprising:

translating the optical head toward a second end-of-travel position;

engaging the adjustment member with a second stop member located at the second end-of-travel position such that the push-rod member is no longer translated.

17. A method of adjusting the location of an object plane above a platen to be scanned by an optical head, the method comprising:

translating the optical head such that a slide member is guided along a ramped surface to adjust the distance between the optical head and the platen; and

engaging an optical head having a ramped surface with a stop member to adjust the distance between the optical head and the platen.

18. An optical image scanner comprising:

a platen;

a stop member at an end-of-travel position; and

an optical head having a ramp member that causes the optical head to move in an orthogonal direction relative to the platen when the optical head is translated into the stop member.

19. The optical image scanner of claim 18 , wherein the optical head further comprises:

a housing;

a slide member having a top portion extending from the housing and engaging the lower surface of the platen; and

an adjustment member having a first end portion extending from a first side of the housing toward the stop member and an interior portion having a ramped surface that engages the lower portion of the slide member such that when the optical head is translated toward the first end-of-travel position the first end portion engages the stop member and the slide member is guided along the ramped surface to adjust the distance between the optical head and the platen.

20. The optical image scanner of claim 19 , wherein the adjustment member comprises a push-rod.