Sheet conveyance apparatus controlling direction for conveying sheet, and image forming apparatus

1. A sheet conveyance apparatus, comprising:

a guide member configured to guide a sheet in a first direction in a first state, and guide the sheet in a second direction in a second state;

a driving source configured to generate a driving force for changing a state of the guide member from the first state to the second state;

a transfer member configured to change the state of the guide member from the first state to the second state by being moved by the driving force generated by the driving source; and

a control unit configured to control the driving force of the driving source,

wherein the control unit is further configured to set the driving force of the driving source to a value smaller than a force necessary to move the transfer member and greater than zero when the guide member is in the first state, and subsequently cause the driving force of the driving source to increase to a value larger than the force necessary to move the transfer member when the guide member is in the first state.

2. The sheet conveyance apparatus according to claim 1 , wherein the control unit is further configured to cause the driving force of the driving source to increase continuously or to cause the driving force of the driving source to increase in units of a predetermined value.

3. The sheet conveyance apparatus according to claim 1 , wherein

the transfer member is moved from a first position to a second position in order to change the guide member from the first state to the second state,

a force necessary to move the transfer member from the first position is a first value, and

the control unit is further configured to set the driving force of the driving source to a second value smaller than the first value when moving the transfer member from the first position, and subsequently cause the driving force of the driving source to increase to a third value larger than the first value.

4. The sheet conveyance apparatus according to claim 3 , further comprising a holding unit configured to hold the second value and the third value.

5. The sheet conveyance apparatus according to claim 3 , wherein

one or more load change positions are present between the first position and the second position, and the force necessary to move the transfer member changes at the one or more load change positions,

a force necessary to move the transfer member from the first position to an initial load change position is the first value,

a force necessary to move the transfer member from the initial load change position to a next load change position or the second position is a fourth value larger than the first value, and

the control unit is further configured to, after causing the driving force of the driving source to increase from the second value to the third value, move the transfer member by the third value to the initial load change position, set the driving force of the driving source to a fifth value smaller than the fourth value when the transfer member reaches the initial load change position, and subsequently cause the driving force of the driving source to increase to a sixth value greater than the fourth value.

6. The sheet conveyance apparatus according to claim 5 , wherein the fifth value is larger than the third value.

7. The sheet conveyance apparatus according to claim 3 , wherein

the transfer member is moved from the first position to the second position via a third position,

the guide member is in the first state when the transfer member is at the first position and the third position, and the guide member is in the second state when the transfer member is at the second position,

the force necessary to move the transfer member is increased at the third position, and

the control unit is further configured to set the driving force of the driving source so that the transfer member reaches the third position when guiding the sheet in the first direction, and set the driving force of the driving source so that the transfer member reaches the second position when guiding the sheet in the second direction.

8. The sheet conveyance apparatus according to claim 7 , wherein

a force necessary to move the transfer member from the third position to the second position is a fourth value larger than the first value, and

the control unit is further configured to set the driving force of the driving source to a value smaller than the fourth value and larger than the first value when causing the transfer member to move from the second position to the third position, and increase the driving force of the driving source to a value larger than the fourth value when causing the guide member to move from the third position to the second position.

9. The sheet conveyance apparatus according to claim 1 , wherein

the driving source is a solenoid, and

the control unit is further configured to control the driving force of the driving source in accordance with an applied voltage for the solenoid.

10. The sheet conveyance apparatus according to claim 1 , further comprising a first conveyance path for conveying the sheet in the first direction, and a second conveyance path for conveying the sheet in the second direction,

wherein the guide member is a flapper for switching a conveyance direction of the sheet.

11. A sheet conveyance apparatus, comprising:

a guide member configured to guide a sheet in a first direction in a first state, and guide the sheet in a second direction in a second state;

a driving source configured to generate a driving force for changing a state of the guide member from the first state to the second state;

a transfer member configured to change the state of the guide member from the first state to the second state by being moved by the driving force generated by the driving source;

a control unit configured to control the driving force of the driving source; and

a measurement unit configured to measure a movement amount of the transfer member,

wherein the control unit is further configured to, by measuring the movement amount of the transfer member while changing the driving force of the driving source, determine a relation between the movement amount of the transfer member and a load of the driving source.

12. The sheet conveyance apparatus according to claim 11 , wherein the control unit is further configured to control the driving force of the driving source based on the relation between the determined movement amount of the transfer member and the load of the driving source.

13. An image formation apparatus, comprising:

a sheet conveyance apparatus, and

an image forming unit configured to form an image on a sheet conveyed by the sheet conveyance apparatus,

wherein

the sheet conveyance apparatus comprises:

a guide member configured to guide a sheet in a first direction in a first state, and guide the sheet in a second direction in a second state;

a driving source configured to generate a driving force for changing a state of the guide member from the first state to the second state;

a transfer member configured to change the state of the guide member from the first state to the second state by being moved by the driving force generated by the driving source; and

a control unit configured to control the driving force of the driving source,

wherein the control unit is further configured to set the driving force of the driving source to a value smaller than a force necessary to move the transfer member and greater than zero when the guide member is in the first state, and subsequently cause the driving force of the driving source to increase to a value larger than the force necessary to move the transfer member when the guide member is in the first state.