Image Forming Apparatus

• US 20150317545A1
• Filed: 04/30/2015
• Published: 11/05/2015
• Est. Priority Date: 05/01/2014
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Miyahara, Kensuke, Kondo, Kunihiko, Kakutani, Hotaka
• Granted Patent: US 10,437,189 B2
• Time in Patent Office: 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 2215/00438 Inverter of refeeding path
• CPC Class Codes: G03G 2215/00586 duplex mode
• CPC Class Codes: G03G 2215/0141 the linear arrangement being horizontal
• CPC Class Codes: G06K 15/00 Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printersprinting or plotting combined with another operation, e.g. with conveying, G06K17/00
• CPC Class Codes: G06K 15/16 Means for paper feeding or form feeding
• CPC Class Codes: G06K 15/1805 Receiving printer configuration commands
• CPC Class Codes: G06K 15/4055 Managing power consumption, e.g. standby mode computer driven power saving management for a printer G06F3/1221; power saving in a data processing device in general G06F1/32

Abstract

An image forming apparatus is provided with: an image forming unit having a photosensitive member, a charger, and a developer carrier, the image forming unit being configured to transfer the developer image to a recording sheet to form an image on the recording sheet; a motor configured to drive the photosensitive member and the developer carrier; a controller configured to control the motor and the charger, and a re-conveyance mechanism configured to reverse the recording sheet discharged from the image forming unit and to convey the recording sheet back towards the image forming unit. The controller is configured to turn off the charger after the motor is turned off, during a time period after the recording sheet is discharged from the image forming unit until the recording sheet is re-conveyed to the image forming unit by the re-conveyance mechanism.

Claims

1. An image forming apparatus comprising:

an image forming unit comprising a photosensitive member configured to rotate, a charger configured to charge a surface of the photosensitive member, and a developer carrier configured to rotate and supply developer to an electrostatic latent image formed on the photosensitive member to form a developer image, the image forming unit being configured to transfer the developer image to a recording sheet to form an image on the recording sheet;

a motor configured to drive the photosensitive member and the developer carrier;

a controller configured to control the motor and the charger; and

a re-conveyance mechanism configured to reverse the recording sheet discharged from the image forming unit and to convey the recording sheet back towards the image forming unit,

wherein the controller is configured to turn off the charger after the motor is turned off, during a time period after the recording sheet is discharged from the image forming unit until the recording sheet is re-conveyed to the image forming unit by the re-conveyance mechanism.

2. The image forming apparatus according to claim 1,

wherein the controller is configured to turn off the charger after rotation of the photosensitive member is stopped.

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

a temperature detector configured to detect a temperature,

wherein the controller sets a time period after the motor is turned off until the charger is turned off to a first delay time when the temperature detected by the temperature detector is equal to or lower than a first temperature, and

wherein the controller sets the time period after the motor is turned off until the charge is turned off to a second delay time that is longer than the first delay time when the temperature detected by the temperature detector is higher than the first temperature.

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

a stop detector configured to detect stop of the photosensitive member,

wherein the controller turns off the charger when the stop of the photosensitive member is detected by the stop detector.

5. The image forming apparatus according to claim 1,

wherein the controller turns on the charger during a time period after the charger is turned off until the recording sheet is re-conveyed to the image forming unit by the re-conveyance mechanism, and

wherein the controller turns on the motor simultaneously with the charger or after turning on the charger.

6. The image forming apparatus according to claim 5,

wherein the controller turns on the charger after turning off the charger and before a surface potential of the photosensitive member is lowered to a predetermined value.

7. The image forming apparatus according to claim 6 further comprising:

a temperature detector configured to detect a temperature,

wherein the controller sets a time period after the charger is turned off until the charger is turned on to a third delay time when the temperature detected by the temperature detector is equal to or lower than a second temperature, and

wherein the controller sets the time period after the charger is turned off until the charger is turned on to a fourth delay time that is shorter than the third delay time when the temperature is higher than the second temperature.

8. The image forming apparatus according to claim 1,

wherein the charger and the developer carrier are configured to be turned on simultaneously by a common power source and a common switch.

9. The image forming apparatus according to claim 1,

wherein the image forming unit comprises a plurality of set of the photosensitive member, the charger and the developer carrier.

10. An image forming apparatus comprising:

an image forming unit comprising;

a photosensitive drum;

a charger configured to charge a surface of the photosensitive drum; and

a developer configured to supply toner to a latent image formed on the photosensitive drum;

a motor configured to drive the photosensitive drum and the developer;

a re-conveyance unit configured to reverse a recording sheet discharged from the image forming unit and to convey the recording sheet towards the image forming unit; and

a controller configured to;

receive a duplex printing job including image data to be formed;

rotate the motor in response to receiving the duplex printing job;

control the image forming unit to form an image on a first surface of a sheet;

stop the motor, during a time period after the recording sheet is discharged from the image forming unit until the recording sheet is re-conveyed to the image forming unit by the re-conveyance unit;

rotate the motor, when the re-conveyance unit starts to convey the recording sheet towards the image forming unit, after the motor is stopped; and

control the image forming unit to form an image on a second surface of the sheet, wherein the second surface of the sheet is opposite to the first surface of the sheet.

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

a sensor provided at upper stream of the image forming unit, the sensor being configured to become an ON state or an OFF state,

wherein the controller is configured to;

determine whether the sensor become the OFF state from the ON state or not; and

stop the motor in response to being determined that the sensor become the OFF state from the ON state.

12. The image forming apparatus according to claim 10, wherein the controller is configured to:

determine whether a predetermined delay time elapses after re-conveyance unit starts to convey the recording sheet towards the image forming unit; and

rotate the motor in response to being determined that the predetermined delay time elapses after re-conveyance unit starts to convey the recording sheet towards the image forming unit.

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

a cam configured to be formed with a recess portion which engages with a rotary shaft of the developer, the recess portion having an inclined surface being extended from a bottom of the recess portion towards an upper of the recess portion; and

a gear configured to contact with the cam, the cam being movable in a predetermined direction in response to the gear rotating in a first direction, wherein the predetermined direction is a direction in which the rotary shaft of the developer contacts with the inclined surface,

wherein the controller is configured to;

rotate the gear in the first direction during the time period after the recording sheet is discharged from the image forming unit until the recording sheet is re-conveyed to the image forming unit by the re-conveyance unit.

14. The image forming apparatus according to claim 13 further comprising:

a clutch configured to switch from a connection state to a cutoff state when the gear is rotated in the first direction, the connection state during which the driving force can be transmitted to the gear and a cutoff state during which the driving force cannot be transmitted to the gear.

15. An image forming apparatus comprising:

an image forming unit comprising;

a plurality of photosensitive drums;

a plurality of chargers configured to charge a surface of the photosensitive drum; and

a plurality of developers configured to supply toner to a latent image formed on the photosensitive drum;

a re-conveyance unit configured to reverse a recording sheet discharged from the image forming unit and to convey the recording sheet towards the image forming unit;

a first motor configured to drive one of the developer and the re-conveyance unit;

a second motor configured to drive all of the photosensitive drums and the other of the developer;

a cam configured to be formed with recess portions, the recess portion being configured to engage with a rotary shaft of the developer and to have an inclined surface extending from a bottom of the recess portion towards an upper of the recess portion;

a gear configured to contact with the cam, wherein the cam is moved in a predetermined direction in response to the gear rotating in a first direction and is moved in an opposite direction of the predetermined direction in response to the gear rotating in a second direction opposite the first direction, wherein the predetermined direction is a direction in which the rotary shaft of the developer contacts with the inclined surface; and

a controller configured to;

receive a duplex printing job including image data to be formed;

rotate the first motor and the second motor in response to receiving the duplex printing job;

control the image forming unit to form an image on a first surface of a sheet;

stop the second motor, during a time period after the recording sheet is discharged from the image forming unit until the recording sheet is re-conveyed to the image forming unit by the re-conveyance unit;

rotate the gear in the first direction in accordance with stopping the second motor;

rotate the second motor, when the re-conveyance unit starts to convey the recording sheet towards the image forming unit, after the motor is stopped;

rotate the gear in opposite direction of the first direction in accordance with rotating the second motor; and

control the image forming unit to form an image on a second surface of the sheet, wherein the second surface of the sheet is opposite to the first surface of the sheet.

16. The image forming apparatus according to claim 15 further comprising:

a clutch configured to switch from a connection state to a cutoff state when the gear is rotated in the first direction, the connection state during which the driving force can be transmitted to the gear and the cutoff state during which the driving force cannot be transmitted to the gear.

17. The image forming apparatus according to claim 15 further comprising:

a sensor provided at upper stream of the image forming unit, the sensor being configured to become an ON state or an OFF state,

wherein the controller is configured to;

determine whether the sensor become the OFF state from the ON state or not; and

stop the motor in response to being determined that the sensor become the OFF state from the ON state.

18. The image forming apparatus according to claim 15, wherein the controller is configured to:

determine whether a predetermined delay time elapses after re-conveyance unit starts to convey the recording sheet towards the image forming unit; and

rotate the motor in response to being determined that the predetermined delay time elapses after re-conveyance unit starts to convey the recording sheet towards the image forming unit.