Scale, measuring apparatus, image formation apparatus, scale fabricating unit, and scale fabrication method
AssigneeCanon Kabushiki Kaisha
InventorTakashi Fukuhara
Life of this patent
Estimating the term…
Abstract
A scale is configured to measure a displacement or velocity of a rotating object. The scale includes a first region that includes a first mark row including a plurality of marks arranged in a first period, and a second region that includes a second mark row including a plurality of marks arranged in a second period having a phase continuity with the first mark row formed in the first region. A periodic mark row including the first mark row and the second mark row is formed over an entire circumference of the rotating object including the first region and the second region.
Claims12
A scale for measuring a displacement or velocity of a rotating object, the scale comprising:
- a first region including a first mark row with a plurality of marks arranged in a first period;
- a second region including a second mark row with a plurality of marks arranged in a second period, which is different from the first period, having a phase continuity with the first mark row in the first region;
- and
- a periodic mark row including the first mark row and the second mark row disposed one after another along a rotating direction of the rotating object,
- wherein the periodic mark row is disposed over an entire circumference of the rotating object, and
- wherein an expression below is satisfied:
- P
-
-
- 2
- =
- P
-
-
- 1
- +
- R
-
-
- 2
- -
- round
-
- (
- R
-
-
- 2
- P
-
-
- 1
- )
- *
- P
-
-
- 1
- round
-
- (
- R
-
-
- 2
- P
-
-
- 1
- )
- ,
- where R2 represents a length of the second region, P1 represents the first period, P2 represents the second period, and round(a) represents an integer to which a value of a is round.
A measuring apparatus comprising:
- a rotating object;
- a scale on a surface of the rotating object;
- a sensor configured to detect a mark row on the scale;
- and
- a measurement unit configured to measure a relative displacement or relative velocity between the rotating object and the sensor,
- wherein the scale includes:
- a first region including a first mark row with a plurality of marks arranged in a first period;
- a second region including a second mark row with a plurality of marks arranged in a second period, which is different from the first period, having a phase continuity with the first mark row in the first region;
- and
- a periodic mark row including the first mark row and the second mark row disposed one after another along a rotating direction of the rotating object,
- wherein the periodic mark row is disposed over an entire circumference of the rotating object, and
- wherein an expression below is satisfied:
- P
-
-
- 2
- =
- P
-
-
- 1
- +
- R
-
-
- 2
- -
- round
-
- (
- R
-
-
- 2
- P
-
-
- 1
- )
- *
- P
-
-
- 1
- round
-
- (
- R
-
-
- 2
- P
-
-
- 1
- )
- ,
- where R2 represents a length of the second region, P1 represents the first period, P2 represents the second period, and round(a) represents an integer to which a value of a is round.
An image formation apparatus comprising:
- a rotating object;
- a scale on a surface of the rotating object;
- a sensor configured to detect a mark row on the scale;
- a measurement unit configured to measure a relative displacement or relative velocity between the rotating object and the sensor;
- a motor configured to rotate the rotating object;
- and
- a controller configured to control the motor based on a measurement result of the measurement unit,
- wherein the scale includes:
- a first region including a first mark row with a plurality of marks arranged in a first period;
- a second region including a second mark row with a plurality of marks arranged in a second period, which is different from the first period, having a phase continuity with the first mark row in the first region;
- and
- a periodic mark row including the first mark row and the second mark row disposed one after another along a rotating direction of the rotating object,
- wherein the periodic mark row is disposed over an entire circumference of the rotating object, and
- wherein an expression below is satisfied:
- P
-
-
- 2
- =
- P
-
-
- 1
- +
- R
-
-
- 2
- -
- round
-
- (
- R
-
-
- 2
- P
-
-
- 1
- )
- *
- P
-
-
- 1
- round
-
- (
- R
-
-
- 2
- P
-
-
- 1
- )
- ,
- where R2 represents a length of the second region, P1 represents the first period, P2 represents the second period, and round(a) represents an integer to which a value of a is round.
Dependencies are inferred from the claim text.