Image forming apparatus

A stack sheet supplying apparatus comprising:

• sheet stacking means;
• supply means for supplying a sheet by contacting with an upper surface of the sheet rested on said sheet stacking means;
• lift/lower means for lifting and lowering said supply means;
• drive means for driving said lift/lower means;
• control means for controlling said drive means to move said supply means into a supply position in which said supply means is contacted with the upper surface of the sheet, a home position in which said supply means is spaced apart from the upper surface of the sheet and a retracted position situated between the supply position and the home position whereby said control means shifts and lowers said supply means between the supply position and the retracted position to supply the sheet.

A stack sheet supplying apparatus comprising:

• sheet stacking means;
• supply means for supplying a sheet by contacting with an upper surface of the sheet rested on said sheet stacking means;
• lift/lower means for lifting and lowering said supply means to move said supply means into a home position, a supply position and a retracted position situated between said home position and said supply position;
• detection means for detecting a fact that said supply means reaches said supply portion;
• drive means for driving said lift/lower means;
• and
• separation supply means disposed at a downstream side of said supply means and adapted to separate sheets;
• wherein when the detection of said detection means is effected, said drive means is turned OFF to stop said lift/lower means, and, after supply, when a leading end of the sheet passes through said separation supply means, said drive means is turned ON to lift said lift/lower means to thereby lift said supply means to said retracted position spaced apart from the upper surface of the sheet, and, thereafter, said drive means is turned ON again in response to supply command to lower said lift/lower means to thereby lower said supply means to said supply position on the upper surface of the sheet.

A stack sheet supplying apparatus comprising:

• sheet stacking means for stacking sheets;
• supply means for supplying a sheet from said sheet stacking means, said supply means having weight and being liftable and lowerable so that said supply means reaches a supply position in which said supply means is in contact with an upper surface of the sheet resting on said sheet stacking means by the self-weight of said supply means to supply the sheet;
• lift/lower means for lifting and lowering said supply means by engaging with a part of said supply means, said lift/lower means being disengaged from the part of said supply means when said supply means reaches the supply position;
• drive means for driving said lift/lower means;
• detection means for detecting said supply means at the supply position;
• and
• control means for controlling ON/OFF of said drive means based on a detected result of detection means.