Image forming apparatus

An image forming apparatus, comprising:

• an image forming station for conveying a sheet material along a stationary lateral reference position and for forming an image on the sheet material;
• refeeding means for refeeding to said image forming station the sheet material on which the image has been formed in said image forming station;
• means for detecting a change in a lateral dimension of the sheet material resulting from an image forming operation to the sheet material in said image forming station;
• and
• means, provided in said sheet refeeding means, for shifting the, sheet material in the lateral direction from the stationary lateral reference position by an amount based on detection by said detecting means.

An image forming apparatus, comprising:

• an image forming station for conveying a sheet material along a lateral reference position and for forming an image on the sheet material;
• refeeding means for refeeding to said image forming station the sheet material on which the image has been formed in said image forming station;
• means for detecting a change in a lateral dimension of the sheet material resulting from an image forming operation to the sheet material in said image forming station;
• and
• means, provided in said sheet refeeding means, for shifting the sheet material in the lateral direction from the lateral reference position by an amount based on detection by said detecting means, wherein said detecting means includes a first detecting element for detecting the lateral dimension of the sheet material prior to the image formation to the sheet material in said image forming station and a second detecting means for detecting the lateral dimension of the sheet material after the image forming operation thereto, and means for comparing detected dimension by said first detecting means and detected dimension by said second detecting means.

An image forming apparatus, comprising:

• an image forming station for forming an image on a sheet material;
• registration means for feeding the sheet material to said image forming station at timing in synchronism with operation of said image forming station;
• refeeding means for refeeding to said image forming station the sheet material on which the image has been formed in said image forming station;
• control means for controlling, when the sheet material is re-fed to said image forming station from said refeeding means, said registration means to delay or advance timing of feeding the sheet by said registration means by a predetermined period of time with respect to the synchronous timing at which the sheet material has been fed by said registration means before the refeeding of the sheet material, wherein an amount of the delay or advancement is predetermined on the basis of a change in a dimension of the sheet material in a conveying direction, resulting from an image forming operation in said image forming station.

An image forming apparatus, comprising:

• an image forming station for forming an image on a sheet material;
• registration means for feeding the sheet material to said image forming station at timing in synchronism with operation of said image forming station;
• refeeding means for refeeding to said image forming station the sheet material on which the image has been formed in said image forming station;
• means for detecting a change in a dimension of the sheet material in a conveying direction, resulting from the image forming operation to the sheet material in said image forming station;
• and
• control means for controlling, when the sheet material is re-fed to said image forming station from said refeeding means, said registration means to delay or advance timing of feeding the sheet by said registration means in accordance with the change detected by said detecting means with respect to the synchronous timing at which the sheet material has been fed by said registration means before the refeeding of the sheet material.

An image forming apparatus, comprising:

• an image forming station for forming an image on a sheet material;
• registration means for feeding the sheet material to said image forming station at timing in synchronism with operation of said image forming station;
• refeeding means for refeeding to said image forming station the sheet material on which the image has been formed in said image forming station;
• means for detecting a change in a dimension of the sheet material in a conveying direction, resulting from the image forming operation to the sheet material in said image forming station;
• and
• control means for controlling, when the sheet material is re-fed to said image forming station from said refeeding means, said registration means to delay or advance timing of feeding the sheet by said registration means in accordance with the change detected by said detecting means with respect to the synchronous timing, wherein said detecting means includes a first detecting element for detecting the dimension of the sheet material prior to completion of the image formation, a second detecting element for detecting the dimension of the sheet material after completion of the image formation and means for comparing detection by said first detecting element and detection by said second detecting element.

An image forming apparatus, comprising:

• an image forming station for forming an image on a sheet material;
• first registration means operable at timing in synchronism with operation of said image forming station to convey the sheet material to said image forming station;
• refeeding means for refeeding to said image forming station the sheet material on which the image has been formed in said image forming station;
• second registration means, disposed in said refeeding means, for conveying the sheet material to said image forming station at registering timing;
• control means for delaying or advancing the registering timing of said second registration means by a predetermined amount with respect to the synchronous timing by said first registration means, wherein the predetermined amount of the delay or advancement is predetermined on the basis of a change in a dimension of the sheet material in a conveying direction, resulting from an image forming operation in said image forming station.

An image forming apparatus, comprising:

• an image forming station for forming an image on a sheet material;
• first registration means operable at timing in synchronism with operation of said image forming station to convey the sheet material to said image forming station;
• refeeding means for refeeding to said image forming station the sheet material on which the image has been formed in said image forming station;
• second registration means, disposed in said refeeding means, for conveying the sheet material to said image forming station at registering timing;
• means for detecting a change in a dimension of the sheet material in a conveying direction resulting from the image forming operation to the sheet material in said image forming station;
• and
• control means for delaying or advancing a registration timing by said second registration means with respect to the synchronous timing by said first registration means in accordance with the change detected by said detecting means.

An image forming apparatus, comprising:

• an image forming station for forming an image on a sheet;
• a rotatable member for transferring the sheet in a first direction toward said image forming station;
• supporting means for supporting said rotatable member for displacement in a second direction which traverses the first direction;
• driving means for displacing said rotatable member in the second direction to correct deviation of the sheet in the second direction;
• and
• inlet guiding means for guiding the sheet to said rotatable member, said guiding means being displaceable in the second direction together with said rotatable member.

An image forming apparatus comprising:

• an image forming station for forming an image on a sheet;
• in a first
• a rotatable member for feeding the sheet direction toward said image forming station, said rotatable member being disposed in a passage of the sheet for refeeding the sheet to said image forming station;
• supporting means for supporting said rotatable member for displacement in a second direction which traverses the first direction;
• driving means for displacing said rotatable member in the second direction to correct deviation of the sheet in the second direction;
• and
• inlet guiding means for guiding the sheet to said rotatable member, said guiding means being displaceable in the second direction together with said rotatable member.