Image forming apparatus having a developer carrier that separates from a photosensitive member during sheet re-conveyance

• US 9,557,694 B2
• Filed: 03/20/2015
• Issued: 01/31/2017
• Est. Priority Date: 03/28/2014
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha (Brother Industries Limited)
• Original Assignee: Brother Kogyo Kabushiki Kaisha (Brother Industries Limited)
• Inventors: Suzuki, Yasuhiro
• Primary Examiner(s): Phan, Minh
• Assistant Examiner(s): Verbitsky, Victor
• Application Number:
  US14/664,455
• Publication Number:
  US 20150277261A1
• Time in Patent Office: 683 Days
• US Class Current: 1/1
• CPC Class Codes: G03G 15/234 by inverting and refeeding the image receiving material with an image on one face to the recording member to transfer a second image on its second face, e.g. by using a duplex tray; Details of duplex trays or inverters
• CPC Class Codes: G03G 2215/0141 the linear arrangement being horizontal
• CPC Class Codes: G03G 2215/0193 transfer member separable from recording member

Abstract

An image forming apparatus includes: an image forming unit including first and second photosensitive members, and first and second developer carriers; a re-conveyance mechanism configured to convey a recording sheet discharged from the image forming unit towards the image forming unit; a separation/stop mechanism configured to switch a developing unit between an image formation mode in which the first developer carrier contacts the first photosensitive member and a separation mode in which the first developer carrier is separated from the first photosensitive member and the second developer carrier is separated from the second photosensitive member, and a control device configured to switch the developing unit from the image formation mode to the separation mode while the re-conveyance mechanism conveys a first recording sheet after the image forming unit forms an image on a first surface of the first recording sheet.

Claims

1. An image forming apparatus comprising:

a photosensitive member;

a rotatable developer carrier;

a transfer member configured to transfer a developer image on a recording sheet at a transfer position;

a feeder mechanism defining a sheet feeding path for feeding the recording sheet to the transfer position, the feeder mechanism including a supply roller arranged on the sheet feeding path;

a re-conveyance mechanism defining a re-conveyance path for re-conveying the recording sheet having passed through the transfer position to the transfer position again, the re-conveyance mechanism including a re-conveyance roller arranged on the re-conveyance path;

an actuator configured to separate the developer carrier from the photosensitive member, and

a control device configured to drive the actuator in a direction in which the developer carrier is separated from the photosensitive member, stop rotation of the developer carrier and stop rotation of the photosensitive member while the re-conveyance roller conveys the recording sheet.

2. The image forming apparatus according to claim 1 further comprising:

a housing configured to accommodate the photosensitive member and the developer carrier;

a discharge tray provided at an outer side of the housing and configured to support the recording sheet discharged to an outside of the housing; and

a switchback roller configured to rotate in a forward direction to convey the recording sheet having passed through the transfer position in a direction coming close to the discharge tray and configured to rotate in a reverse direction opposite to the forward direction,

wherein the control device is configured to drive the actuator after a rotating direction of the switchback roller is switched from the forward direction to the reverse direction.

3. The image forming apparatus according to claim 2, wherein the control device is configured to drive the actuator in a direction in which the developer carrier is separated from the photosensitive member after the rotating direction of the switchback roller is switched from the forward direction to the reverse direction.

4. The image forming apparatus according to claim 1, wherein the control device is configured to stop rotation of the photosensitive member while the re-conveyance roller conveys the recording sheet.

5. The image forming apparatus according to claim 1, wherein

the transfer member includes a rotatable belt, and

the control device is configured to stop rotation of the belt while the re-conveyance roller conveys the recording sheet.

6. The image forming apparatus according to claim 1, wherein the control device is configured to stop rotation of the re-conveyance roller while the control device drives the actuator.

7. The image forming apparatus according to claim 1, wherein one end of the re-conveyance path is connected to one end of the sheet feeding path.

8. The image forming apparatus according to claim 2, wherein the housing includes the discharge tray.

9. An image forming apparatus comprising:

a photosensitive member;

a rotatable developer carrier;

a transfer member configured to transfer a developer image on a recording sheet at a transfer position;

a feeder mechanism defining a sheet feeding path for feeding the recording sheet to the transfer position, the feeder mechanism including a supply roller arranged on the sheet feeding path;

a re-conveyance mechanism defining a re-conveyance path for re-conveying the recording sheet having passed through the transfer position to the transfer position again, the re-conveyance mechanism including a re-conveyance roller arranged on the re-conveyance path;

an actuator configured to separate the developer carrier from the photosensitive member, and

a control device configured to drive the actuator in a direction in which the developer carrier is separated from the photosensitive member and stop rotation of the developer carrier while the re-conveyance roller conveys the recording sheet,

wherein the transfer member includes a rotatable belt, and

wherein the control device is configured to stop rotation of the belt while the re-conveyance roller conveys the recording sheet.

10. The image forming apparatus according to claim 9 further comprising:

a housing configured to accommodate the photosensitive member and the developer carrier;

a discharge tray provided at an outer side of the housing and configured to support the recording sheet discharged to an outside of the housing; and

a switchback roller configured to rotate in a forward direction to convey the recording sheet having passed through the transfer position in a direction coming close to the discharge tray and configured to rotate in a reverse direction opposite to the forward direction,

wherein the control device is configured to drive the actuator after a rotating direction of the switchback roller is switched from the forward direction to the reverse direction.

11. The image forming apparatus according to claim 10, wherein the control device is configured to drive the actuator in a direction in which the developer carrier is separated from the photosensitive member after the rotating direction of the switchback roller is switched from the forward direction to the reverse direction.

12. The image forming apparatus according to claim 11, wherein the control device is configured to stop rotation of the photosensitive member while the re-conveyance roller conveys the recording sheet.

13. The image forming apparatus according to claim 11, wherein

the transfer member includes a rotatable belt, and

the control device is configured to stop rotation of the belt while the re-conveyance roller conveys the recording sheet.

14. The image forming apparatus according to claim 9, wherein the control device is configured to stop rotation of the re-conveyance roller while the control device drives the actuator.

15. The image forming apparatus according to claim 9, wherein one end of the re-conveyance path is connected to one end of the sheet feeding path.

16. The image forming apparatus according to claim 10, wherein the housing includes the discharge tray.

17. An image forming apparatus comprising:

a photosensitive member;

a rotatable developer carrier;

a transfer member configured to transfer a developer image on a recording sheet at a transfer position;

a feeder mechanism defining a sheet feeding path for feeding the recording sheet to the transfer position, the feeder mechanism including a supply roller arranged on the sheet feeding path;

a re-conveyance mechanism defining a re-conveyance path for re-conveying the recording sheet having passed through the transfer position to the transfer position again, the re-conveyance mechanism including a re-conveyance roller arranged on the re-conveyance path;

an actuator configured to separate the developer carrier from the photosensitive member, and

a control device configured to drive the actuator while the re-conveyance roller conveys the recording sheet, wherein the control device is configured to stop rotation of the re-conveyance roller while the control device drives the actuator.

18. The image forming apparatus according to claim 17, wherein the control device is configured to drive the actuator in a direction in which the developer carrier is separated from the photosensitive member while the re-conveyance roller conveys the recording sheet.

19. The image forming apparatus according to claim 18, wherein the control device is configured to stop rotation of the developer carrier while the re-conveyance roller conveys the recording sheet.

20. The image forming apparatus according to claim 19 further comprising:

a housing configured to accommodate the photosensitive member and the developer carrier;

a discharge tray provided at an outer side of the housing and configured to support the recording sheet discharged to an outside of the housing; and

a switchback roller configured to rotate in a forward direction to convey the recording sheet having passed through the transfer position in a direction coming close to the discharge tray and configured to rotate in a reverse direction opposite to the forward direction,

wherein the control device is configured to drive the actuator after a rotating direction of the switchback roller is switched from the forward direction to the reverse direction.

21. The image forming apparatus according to claim 18, wherein one end of the re-conveyance path is connected to one end of the sheet feeding path.

22. The image forming apparatus according to claim 20, wherein the housing includes the discharge tray.