Pressurizing device, image forming apparatus, and control, method for pressurizing device

Patent metadata

Field	Value
Publication number	US-9836004-B2
Application number	US-201615209881-A
Country	US
Kind code	B2
Filing date	Jul 14, 2016
Priority date	Jul 27, 2015
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A pressurizing device includes: first and second rollers that holds a sheet-like medium with an image bearer formed on at least part of a surface of thereof between the first and second rollers and send the medium in a conveying direction while applying a pressure to the medium; a position control unit that performs feedback control of the position of at least one of the first and second rollers; a force control unit that performs feedback control of a force acting on between the first and second rollers; and a control-method switching unit that switches, after the position of the first and second rollers is switched from a separation position to a contact position by the feedback control performed by the position control unit, a feedback controlled object so that the force becomes a target value of nip pressure through the feedback control performed by the force control unit.

First claim

What is claimed is:

1. A pressurizing device comprising:
first and second rollers configured to hold a sheet-like medium with an image bearer formed on at least part of a surface of the medium between the first and second rollers and send the medium in a conveying direction while applying a pressure to the medium;
a driving unit configured to displace a position of at least one of the first and second rollers to make the first and second rollers come relatively closer to or relatively more separated from each other;
a position control unit configured to control the driving unit, and perform feedback control of the position of at least one of the first and second rollers;
a force control unit configured to control the driving unit, and perform feedback control of a force acting on the first and second rollers;
a control-method switching unit configured to switch, after the position of the first and second rollers is displaced from a relatively more separated separation position to a relatively closer contact position by the feedback control performed by the position control unit, a feedback controlled object so that the force becomes a target value of nip pressure through the feedback control performed by the force control unit; and
a position detecting unit configured to detect the position of the second roller, wherein
the driving unit is configured to displace the position of the second roller to make the first and second rollers come relatively closer to or relatively more separated from each other,
the position control unit is configured to perform feedback control of the position of the second roller based on a difference between a contact-position target profile defining time transition of a target position of the second roller in response to the first and second rollers being put into a relatively closer contact position and a result of detection by the position detecting unit, and
in response to the position of the second roller detected by the position detecting unit at the target position defined in the contact-position target profile, the control-method switching unit is configured to switch from the feedback control performed by the position control unit to the feedback control performed by the force control unit.

2. The pressurizing device of claim 1 , further comprising an entry detecting unit configured to detect an entry of the medium into a nip between the first and second rollers, wherein
in response to the entry detecting unit detecting the entry of the medium into the nip in a state where the first and second rollers are in a relatively more separated position, the control-method switching unit is configured to cause the position control unit to put the first and second rollers into a relatively closer contact position, and then is configured to cause the force control unit to set a nip pressure between the first and second rollers as the target value.

3. The pressurizing device of claim 2 , further comprising an escape detecting unit configured to detect the escape of the medium from the nip, wherein
in response to the escape detecting unit detecting the escape of the medium from the nip in a state where the first and second rollers are in a relatively closer position, the control-method switching unit is configured to cause the position control unit to put the first and second rollers into a relatively more separated position.

4. The pressurizing device of claim 1 , wherein
in response to the position of the second roller detected by the position detecting unit becoming stabilized at the target position defined in the contact-position target profile, the position control unit is configured to store a driving force of the driving unit when the position becomes stabilized in a storage unit, and
the force control unit is configured to determine a driving force after switching from the feedback control performed by the position control unit to the feedback control performed by the force control unit based on the driving force stored in the storage unit.

5. The pressurizing device of claim 1 , wherein
the position detecting unit is configured to detect the position of the second roller at an end of contact control of the first and second rollers performed by the force control unit, and
the position control unit is configured to update the contact-position target profile by using the position of the second roller detected by the position detecting unit at the end of the contact control, and is configured to perform feedback control of the driving unit by using the updated contact-position target profile in response to the first and second rollers being brought into a next relatively closer contact position.

6. The pressurizing device of claim 5 , wherein
before the end of the contact control, the position detecting unit is configured to detect a position history of the second roller thereby storing a plurality of position information in the storage unit, and
the position control unit is configured to update the contact-position target profile based on the plurality of position information stored in the storage unit.

7. An image forming apparatus, comprising the pressurizing device of claim 1 .

8. A pressurizing device comprising:
first and second rollers configured to hold a sheet-like medium with an image bearer formed on at least part of a surface of the medium between the first and second rollers and send the medium in a conveying direction while applying a pressure to the medium;
a driving unit configured to displace a position of at least one of the first and second rollers to make the first and second rollers come relatively closer to or relatively more separated from each other;
a position control unit configured to control the driving unit, and perform feedback control of the position of at least one of the first and second rollers;
a force control unit configured to control the driving unit, and perform feedback control of a force acting on the first and second rollers;
a control-method switching unit configured to switch, after the position of the first and second rollers is displaced from a relatively more separated separation position to a relatively closer contact position by the feedback control performed by the position control unit, a feedback controlled object so that the force becomes a target value of nip pressure through the feedback control performed by the force control unit; and
a force detecting unit configured to detect a force acting on the first and second rollers, wherein the force control unit is configured to perform feedback control of the force acting on the first and second rollers on the basis of a difference between a force target profile defining time transition of a target value of force acting on the first and second rollers in response to the first and second rollers being put into a relatively closer contact position and a result of detection by the force detecting unit.

9. An image forming apparatus, comprising the pressurizing device of claim 8 .

10. A control method performed by a pressurizing device, the pressurizing device including:
first and second rollers configured to hold a sheet-like medium with an image bearer formed on at least part of a surface of the medium between the first and second rollers and send the medium in a conveying direction while applying a pressure to the medium; and
a driving unit configured to displace the position of at least one of the first and second rollers to make the first and second rollers come relatively closer to or relatively more separated from each other, and
a position detecting unit configured to detect the position of the second roller
the control method comprising:
controlling the drivi

Assignees

• Oikawa Ken
• Takahashi Minoru
• Ricoh Co Ltd

Inventors

• Oikawa Ken
• Takahashi Minoru

Classifications

• G03G15/6529 Primary

  Transporting (G03G15/6555 takes precedence) · CPC title

• G03G15/168

  with means for conditioning the transfer element, e.g. cleaning · CPC title

• G03G15/167

  at least one of the recording member or the transfer member being rotatable during the transfer · CPC title