Image forming apparatus
An image forming apparatus includes an image bearing member, a charging unit, a developing unit, a transfer unit, a residual developer collecting container, a developer feeding unit, a driving unit configured to drive the developer feeding unit and at least one of the image bearing member, the developing unit and the transfer unit, and a control unit configured to change a driving speed of the driving unit depending on a storing amount of the residual developer in the collecting container in a period from an end of formation of an image on a first recording material to a start of formation of the image on a second recording material subsequent to the first recording material.
1. An image forming apparatus comprising:
an image bearing member;
a charging unit configured to electrically charge said image bearing member;
a developing unit configured to deposit a developer on a surface of the charged image bearing member;
a transfer unit configured to transfer the developer from said image bearing member onto a recording material;
a collecting container configured to collect a residual developer remaining on the surface of said image bearing member without being transferred onto the recording material;
a developer feeding unit configured to feed, from said collecting container, the residual developer collected in said collecting container;
a driving unit configured to drive said developer feeding unit and at least one of said image bearing member, said developing unit and said transfer unit; and
a control unit configured to change a driving speed of said driving unit depending on a storing amount of the residual developer in said collecting container in a period from an end of formation of an image on a first recording material to a start of formation of the image on a second recording material subsequent to the first recording material.
2. The image forming apparatus according to claim 1 , wherein said control unit drives said driving unit or stops drive of said driving unit depending on the storing amount of the residual developer in said collecting container in the period.
3. The image forming apparatus according to claim 1 , wherein said control unit includes,
an acquiring unit configured to acquire the storing amount of the residual developer in said collecting container, and
a calculating unit configured to calculate a warning amount, of the residual developer, smaller than capacity of said collecting container,
wherein when the storing amount of the residual developer exceeds the warning amount, said control unit drives said driving unit until the storing amount decreases to the warning amount or less.
4. The image forming apparatus according to claim 3 , wherein said calculating unit calculates the warning amount on the basis of the capacity of said collecting container and a collecting amount of the residual developer collected by the formation of the image on the second recording material.
5. The image forming apparatus according to claim 4 , wherein said calculating unit calculates the collecting amount of the residual developer on the basis of a print ratio in the formation of the image on the second recording material.
6. The image forming apparatus according to claim 3 , wherein said control unit calculates a driving time, of said driving unit, necessary to decrease the storing amount of the residual developer to the warning amount or less.
7. The image forming apparatus according to claim 3 , wherein said control unit extends the period until the storing amount decreases to the warning amount or less.
8. The image forming apparatus according to claim 3 , wherein even in a case where the storing amount of the residual developer exceeds the warning amount, said control unit does not change the driving speed of said driving unit in a case where there is no recording material subsequent to the second recording material and the storing amount of the residual developer does not exceed the capacity of said collecting container even when a collecting amount of the residual developer collected by the formation of the image on the second recording material is added to the storing amount.
9. The image forming apparatus according to claim 1 , wherein said control unit includes a predicting unit configured to predict the storing amount from at least one of a print ratio of the developer, a transfer efficiency of the developer onto the recording material and an amount of the residual developer fed by said storing unit.
10. The image forming apparatus according to claim 1 , further comprising a detecting unit configured to detect the storing amount.
11. The image forming apparatus according to claim 1 , wherein said control unit increases the driving speed of said driving unit depending on the storing amount of the residual developer in said collecting container in the period.