Internal residual stress calculating device, non-transitory computer-readable medium, and internal residual stress calculating method
View Patent ↗An internal residual stress calculating device includes a prediction unit that predicts a temporal variation in deformation which is received by a medium having an image formed thereon from a correcting device correcting a deformation, and a calculation unit that calculates an internal residual stress of the medium having passed through the correcting device on the basis of a relational expression including an elasticity term and a term related to a plastic deformation and the temporal variation in deformation predicted by the prediction unit.
1. An image forming apparatus comprising:
a prediction unit that predicts a temporal variation in deformation which is received by a medium having an image formed thereon from a correcting device correcting a deformation;
a calculation unit that calculates an internal residual stress of the medium having passed through the correcting device on the basis of a relational expression including an elasticity term and a term related to a plastic deformation, and the temporal variation in deformation predicted by the prediction unit, the elasticity term including a component corresponding to a distortion at predetermined points in the medium; and
a correction unit that corrects a position of the medium, by forcibly deforming the medium, based upon the calculation by the calculation unit, the forcibly deforming of the medium occurring by applying a pressing force to the medium.
2. The image forming apparatus according to claim 1 , wherein the relational expression used in the calculation unit is selected depending on the type of the medium from expressions:
If
-
σ
Y
≤
σ
≤
σ
Y
is
satisfied
,
ε
.
=
σ
.
K
Otherwise
,
ε
.
=
σ
.
K
+
σ
-
σ
Y
(
ε
)
μ
is
used
,
(
1
)
If
-
σ
Y
≤
σ
≤
σ
Y
is
satisfied
,
σ
i
n
+
1
=
σ
i
n
+
K
Δε
Otherwise
,
σ
i
n
+
1
=
K
Δε
+
σ
Y
i
n
(
ε
,
ε
.
)
is
used
,
and
(
2
)
If
-
σ
Y
≤
σ
≤
σ
Y
is
satisfied
,
σ
i
n
+
1
=
σ
i
n
+
K
Δε
Otherwise
,
σ
i
n
+
1
=
σ
i
n
+
(
K
-
σ
Y
i
n
(
ε
,
ε
.
)
ε
Y
i
n
(
ε
,
ε
.
)
)
Δε
=
σ
i
n
+
K
′
(
ε
,
ε
.
)
Δε
is
used
,
(
3
)
where K represents an elastic modulus, μ represents a viscosity coefficient, ε represents a distortion, σ Y represents a yield stress, and σ i n represents a stress at point i at time n.
3. The image forming apparatus according to claim 1 , further comprising:
a storage unit that stores information representing the temporal variation in deformation which is received by the medium from the correcting device in advance,
wherein the prediction unit predicts the temporal variation in deformation which is received by the medium from the correcting device on the basis of the information stored in the storage unit.
4. The image forming apparatus according to claim 2 , further comprising:
a storage unit that stores information representing the temporal variation in deformation which is received by the medium from the correcting device in advance,
wherein the prediction unit predicts the temporal variation in deformation which is received by the medium from the correcting device on the basis of the information stored in the storage unit.
5. The image forming apparatus according to claim 2 , wherein Expression 2 is selected when the medium is a coated sheet of paper.
6. The image forming apparatus according to claim 2 , wherein Expression 3 is selected when the medium is a medium having a water content above a predetermined level.
7. A non-transitory computer-readable medium storing a program which causes a computer to serve as:
a prediction unit that predicts a temporal variation in deformation which is received by a medium having an image formed thereon from a correcting device correcting a deformation;
a calculation unit that calculates an internal residual stress of the medium having passed through the correcting device on the basis of a relational expression including an elasticity term and a term related to a plastic deformation and the temporal variation in deformation predicted by the prediction unit, the elasticity term including a component corresponding to a distortion at predetermined points in the medium; and
correction twit that corrects a position of the medium, by forcibly deforming the medium, based upon the calculation by the calculation unit, the forcibly deforming of the medium occurring by applying a pressing force to the medium.
8. A correction method comprising:
predicting, using a prediction unit, a temporal variation in deformation which is received by a medium having an image formed thereon from a correcting device correcting a deformation;
calculating, using a calculation unit, an internal residual stress of the medium having passed through the correcting device on the basis of a relational expression including an elasticity term and a term related to a plastic deformation and the temporal variation in deformation predicted by the prediction unit, the elasticity term including a component corresponding to a distortion at predetermined points in the medium; and
correcting a position of the medium, by forcibly deforming the medium based upon the calculation by the calculation unit, the forcibly deforming of the medium occurring by applying a pressing force to the medium.