Sheet supply apparatus, image forming apparatus, sheet supply control method, and computer readable medium

1. A sheet supply apparatus comprising:

a sheet storing part that stores sheets;

a sheet transport part that feeds the sheets from the sheet storing part and transports the sheets;

a sheet separating part that separates the sheets fed by the sheet transport part from the sheet storing part;

a sheet thickness measuring part disposed downstream of the sheet separating part and in the conveying path of the sheets that measures a thickness of individual sheets separated by the sheet separating part;

a sheet separating strength varying part that causes the sheet separating part to apply one or more of a plurality of sheet separating strengths to separate the sheets; and

a control part that controls the sheet separating strength varying part to cause the sheet separating part to apply, from among the plurality of sheet separating strengths, one or more sheet separating strengths, other than a weakest sheet separating strength, during a start of an initial time period during which a predetermined number of the sheets is transported by the sheet transport part,

after the first sheet of the predetermined number of sheets is measured by the sheet thickness measuring part during the initial time period, the control part controls the sheet separating strength varying part to cause the sheet separating part to apply a sheet separating strength based on the thickness of the first sheet of the predetermined number of sheets, and

upon completion of the initial time period, the control part controls the sheet separating strength varying part to cause the sheet separating part to apply another sheet separating strength based on an average thickness of the predetermined number of sheets separated by the sheet separating part.

2. The sheet supply apparatus according to claim 1 , wherein

the control part controls the sheet separating strength varying part to cause the sheet separating part to apply, from among the plurality of sheet separating strengths, one or more sheet separating strengths, other than a weakest sheet separating strength, during the initial time period which begins upon any one of, attachment of a sheet tray to the sheet storing part, recovery of a sheet jam, or entry by a user of a request for measurement of a thickness of one of the sheets separated by the sheet separating part, and ends when a predetermined number of the sheets has been transported by the sheet transport part, whereby the sheet separating strength varying part causes the sheet separating part to apply a sheet separating strength based on the thickness of the average thickness of the predetermined number of sheets during a second time period beginning after the initial time period ends.

3. The sheet supply apparatus according to claim 1 , wherein the sheet separating part comprises:

a transporting roller, provided at a set position on a sheet transporting path, that transports a sheet in contact with a cylindrical surface of the transporting roller along the sheet transport path upon rotation of the transporting roller about a shaft; and

a separating roller, provided to closely oppose the transporting roller at the set position on the sheet transporting path, that is rotatable in a same direction as a rotating direction of the transporting roller when pressed against the transporting roller.

4. An image forming apparatus comprising:

the sheet supply apparatus according to claim 1 ; and

an image forming unit that forms an image on a sheet supplied from the sheet supply apparatus.

5. A sheet supply control method for controlling sheet supply actions performed by a sheet supply apparatus, the method comprising:

providing a sheet supply apparatus having,

a sheet storing part that stores sheets,

a sheet transport part that feeds the sheets from the sheet storing part and transports the sheets,

a sheet separating part that separates the sheets fed by the sheet transport part from the sheet storing part,

a sheet thickness measuring part disposed downstream of the sheet separating part and in the conveying path of the sheets that measures a thickness of individual sheets separated by the sheet separating part, and

a sheet separating strength varying part that causes the sheet separating part to apply one or more of a plurality of sheet separating strengths to separate the sheets; and

controlling the sheet separating strength varying part to cause the sheet separating part to apply, from among the plurality of sheet separating strengths, one or more sheet separating strengths, other than a weakest sheet separating strength, during a start of an initial time period during which a predetermined number of the sheets is transported by the sheet transport part,

after the first sheet of the predetermined number of sheets is measured by the sheet thickness measuring part during the initial time period, controlling the sheet separating strength varying part to cause the sheet separating part to apply a sheet separating strength based on the thickness of the first sheet of the predetermined number of sheets, and

upon completion of the initial time period, controlling the sheet separating strength varying part to cause the sheet separating part to apply another sheet separating strength based on an average thickness of the predetermined number of sheets separated by the sheet separating part.

6. The sheet supply control method according to claim 5 , comprising:

controlling the sheet separating strength varying part to cause the sheet separating part to apply, from among the plurality of sheet separating strengths, one or more sheet separating strengths, other than a weakest sheet separating strength, during the initial time period which begins upon any one of, attachment of a sheet tray to the sheet storing part, recovery of a sheet jam, or entry by a user of a request for measurement of a thickness of one of the sheets separated by the sheet separating part, and ends when a predetermined number of the sheets has been transported by the sheet transport part; and

controlling the sheet separating strength varying part to cause the sheet separating part to apply a sheet separating strength based on the thickness of the average thickness of the predetermined number of sheets during a second time period beginning after the initial time period ends.

7. A non-transitory computer readable storage medium for storing a program causing a computer installed in a sheet supply apparatus to execute one or more programs, the one or more programs comprising instructions to:

control a sheet separating strength varying part of the sheet supply apparatus to cause a sheet separating part to apply, from among the plurality of sheet separating strengths, one or more sheet separating strengths, other than a weakest sheet separating strength, during a start of an initial time period during which a predetermined number of the sheets is transported by a sheet transport part,

after the first sheet of the predetermined number of sheets is measured at a location downstream from the sheet separating part by a sheet thickness measuring part during the initial time period, control the sheet separating strength varying part to cause the sheet separating part to apply a sheet separating strength based on the thickness of the first sheet of the predetermined number of sheets, and

upon completion of the initial time period, control the sheet separating strength varying part to cause the sheet separating part to apply another sheet separating strength based on an average thickness of the predetermined number of sheets separated by the sheet separating part.

8. A non-transitory computer readable storage medium for storing a program wherein the one or more programs comprises instructions to:

control the sheet separating strength varying part to cause the sheet separating part to apply, from among the plurality of sheet separating strengths, one or more sheet separating strengths, other than a weakest sheet separating strength, during the initial time period which begins upon any one of, attachment of a sheet tray to a sheet storing part, recovery of a sheet jam, or entry by a user of a request for measurement of a thickness of one of the sheets separated by the sheet separating part, and ends when a predetermined number of the sheets has been transported by the sheet transport part; and

control the sheet separating strength varying part to cause the sheet separating part to apply a sheet separating strength based on the thickness of the average thickness of the predetermined number of sheets during a second time period beginning after the initial time period ends.