Image forming apparatus and control method thereof

• US 8,750,779 B2
• Filed: 12/10/2007
• Issued: 06/10/2014
• Est. Priority Date: 02/01/2007
• Status: Active Grant

• Current Assignee: HP Printing Korea Co., Ltd. (HP Inc.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ahn, Byeong Hwa, Choi, Bong Hwan, Jo, Yong Kon
• Primary Examiner(s): HA, NGUYEN Q
• Application Number:
  US11/953,236
• Publication Number:
  US 20080187381A1
• Time in Patent Office: 2,374 Days
• Field of Search: 399/361, 399/363, 399/364, 399/381, 399/401, 399/402, 399/405, 399/406, 399/407
• US Class Current: 399/405
• CPC Class Codes: B41J 11/0095 Detecting means for copy material, e.g. for detecting or sensing presence of copy material or its leading or trailing end
• CPC Class Codes: B41J 13/0036 in the output section of automatic paper handling systems
• CPC Class Codes: B41J 13/0045 concerning sheet refeed sections of automatic paper handling systems, e.g. intermediate stackers printing on both faces B41J3/60
• CPC Class Codes: B41J 13/025 Special roller holding or lifting means, e.g. for temporarily raising one roller of a pair of nipping rollers for inserting printing material
• CPC Class Codes: B41J 13/03 driven, e.g. feed rollers separate from platen
• CPC Class Codes: B65H 2301/3332 Tri-rollers type
• CPC Class Codes: B65H 2801/06 Office-type machines, e.g. photocopiers
• CPC Class Codes: G03G 15/231 Arrangements for copying on both sides of a recording or image-receiving material
• CPC Class Codes: G03G 15/6529 Transporting G03G15/6555 takes precedence
• CPC Class Codes: H04N 1/00567 Handling of original or reproduction media, e.g. cutting, separating, stacking
• CPC Class Codes: H04N 1/00591 from the scanning position H04N1/00572 takes precedence
• CPC Class Codes: H04N 1/00612 Path switches H04N1/00575, H04N1/00623, H04N1/00633 take precedence
• CPC Class Codes: H04N 1/00631 Ejecting or stacking H04N1/00641 takes precedence
• CPC Class Codes: H04N 1/00657 Compensating for different handling speeds of different apparatus or arrangements for handling a plurality of sheets simultaneously, e.g. mechanical buffering

Abstract

An image forming apparatus capable of increasing the speed of successively discharging printed printing media in order to increase the overall print speed and a control method thereof. The image forming apparatus includes a first discharge roller to feed printed printing medium rearward from a print unit disposed at an inner front portion of a main body, a reverse roller to reverse a moving direction of the printed printing medium fed from the first discharge roller from a rear to a front of the main body, a second discharge roller to discharge the printed printing medium whose moving direction is reversed outside, and an intermediate discharge roller unit which is provided between the first discharge roller and the reverse roller, the intermediate discharge roller unit including a main roller, a sub discharge roller and a sub supply roller which are in contact with the main roller. While a preceding printed printing medium fed from the reverse roller is discharged between the main roller and the sub discharge roller, a following printed printing medium fed from the first discharge roller is supplied between the main roller and the sub supply roller. Accordingly, since the interval between the preceding printed printing medium and the following printed printing medium becomes shorter than that of a conventional image forming apparatus, the speed of successively discharging printed printing media increases, and as a result the overall print speed increases.

Claims

1. An image forming apparatus, comprising:

a main body having a discharge tray provided at a front portion of the main body;

a print unit to perform a printing operation on a printing medium, the print unit including a plurality of developing devices, a transfer belt arranged between the plurality of developing devices and a front panel of the main body, and a fixing device;

a first discharge roller to feed the printed printing medium fed from the print unit;

a reverse roller to reverse a moving direction of the printed printing medium fed from the first discharge roller;

a swing roller to swing upward to interact with the reverse roller;

a second discharge roller to discharge the printed printing medium fed from the reverse roller to the discharge tray of the main body;

a duplex-print circulation path provided between the transfer belt and the front panel of the main body to feed the printing medium to the print unit; and

a sensor provided between the fixing device of the print unit and the reverse roller to sense a portion of the printing medium,

wherein, in a duplex printing mode, after a printing operation is performed on a first side of a printing medium and a moving direction of the printing medium engaged by the reverse roller is reversed, the reversed printing medium is fed to the duplex-print circulation path to perform a printing operation on a second side of the printing medium, and

wherein, in the duplex printing mode, after the printing operation is performed on the second side of the printing medium, the printing medium is fed by the first discharge roller to the reverse roller, and a moving direction of the printing medium is reversed by the reverse roller, the reversed printing medium is discharged to the discharge tray via the second discharge roller,

wherein, in the duplex printing mode, when a predetermined time elapses after the sensor senses the portion of the printing medium, the moving direction of the printing medium is reversed by the reverse roller.

2. The image forming apparatus according to claim 1, wherein the first discharge roller is provided between the fixing device and the reverse roller to feed the printing medium fed from the print unit.

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

an intermediate discharge roller unit which is provided on a path between the first discharge roller and the second discharge roller, the intermediate discharge roller unit including a main roller, a sub discharge roller and a sub supply roller which are in contact with the main roller,

wherein the swing roller swings upward to contact the printed printing medium to the reverse roller to guide the printed printing medium fed from the first discharge roller to the second discharge roller, and

wherein when a rear end of the printed printing medium passes through between the main roller and the sub supply roller, the swing roller contacts the printed printing medium to the reverse roller to reverse the moving direction of the printed printing medium, and when the rear end of the printed printing medium whose moving direction is reversed advances between the main roller and the sub discharge roller, the swing roller moves away from the reverse roller.

4. The image forming apparatus according to claim 3,

wherein the intermediate discharge roller unit including the main roller and the sub discharge roller is provided between the second discharge roller and the reverse roller.

5. The image forming apparatus according to claim 3,

wherein while a preceding printed printing medium fed from the reverse roller is discharged between the main roller and the sub discharge roller, a following printed printing medium fed from the first discharge roller is supplied between the main roller and the sub supply roller, and

wherein the swing roller moves away from the reverse roller before the following printed printing medium is fed to between the main roller and the sub supply roller.

6. The image forming apparatus according to claim 5, wherein the portion of the printing medium sensed by the sensor corresponds to a rear end of the printed printing medium.

7. The image forming apparatus according to claim 6, wherein:

a time required for the rear end of the printed printing medium to pass between the main roller and the sub supply roller of the intermediate discharge roller unit after the rear end of the printed printing medium is sensed by the sensor is approximately 50 ms,

an ascending time of the swing roller is approximately 100 ms,

a descending time of the swing roller is approximately 100 ms, and

a process speed is approximately 150 mm/sec.

8. A method to control an image forming apparatus including a main body having a discharge tray provided at a front portion of the main body, a print unit to perform a printing operation on a printing medium and including a plurality of developing devices and a transfer belt arranged between the plurality of developing devices and a front panel of the main body, and a printing medium discharge unit including a first discharge roller to feed the printed printing medium rearward from the print unit, a reverse roller to reverse a moving direction of the printed printing medium fed from the first discharge roller from a rear to a front of the main body, a swing roller to swing upward to interact with the reverse roller, and a second discharge roller to discharge the printed printing medium to an outside of the main body, the method comprising:

in a duplex printing mode, after a printing operation is performed on a first side of a printing medium and a moving direction of the printing medium engaged by the reverse roller is reversed, feeding the printing medium to a duplex-print circulation path provided between the transfer belt and the front panel of the main body and configured to feed the printing medium to the print unit such that a printing operation is performed on a second side of the printing medium; and

in the duplex printing mode, after the printing operation is performed on the second side of the printing medium and the moving direction of the printing medium engaged by the reverse roller is reversed, discharging the printing medium to the discharge tray via the second discharge roller.

9. The method according to claim 8, wherein the swing roller is provided adjacent to the reverse roller to guide the printed printing medium fed from the first discharge roller to the second discharge roller, and an intermediate discharge roller unit is further provided on a path between the first discharge roller and the second discharge roller, the intermediate discharge roller unit including a main roller, a sub discharge roller and a sub supply roller which are in contact with the main roller, and the method further comprises:

if the rear end of the printed printing medium passes through between the main roller and the sub supply roller, controlling the swing roller to contact the printed printing medium to the reverse roller to reverse the moving direction of the printed printing medium; and

if the rear end of the printed printing medium whose moving direction is reversed advances between the main roller and the sub discharge roller, making the swing roller move away from the reverse roller.

10. The method according to claim 9, wherein the swing roller moves away from the reverse roller before the following printed printing medium is fed to the main roller and the sub supply roller.

11. An image forming apparatus, comprising:

a main body having a discharge tray provided at a front portion of the main body;

a print unit to perform a printing operation on a printing medium, the print unit including a plurality of developing devices and a transfer belt arranged between the plurality of developing devices and a front panel of the main body;

a swing roller to swing upward between a first position and a second position;

a reverse roller to interact with the swing roller to change a feeding path of the printing medium;

a first discharge roller located to feed the printing medium toward the reverse roller; and

a second discharge roller to discharge the printing medium fed from the reverse roller to the discharge tray of the main body,

wherein, in a duplex printing mode, after a printing operation is performed on a first side of the printing medium and a moving direction of the printing medium engaged by the reverse roller is reversed, the printing medium is fed to a duplex-print circulation path provided between the transfer belt and the front panel of the main body and configured to feed the printing medium to the print unit such that a printing operation is performed on a second side of the printing medium, and

wherein, in the duplex printing mode, after the printing operation is performed on the second side of the printing medium and the moving direction of the printing medium engaged by the reverse roller is reversed, the printing medium is discharged to the discharge tray via the second discharge roller.

12. The apparatus of claim 11, further comprising:

a sensor disposed between the reverse roller and a fixing unit to sense the printing medium,

wherein the swing roller moves from the first position to the second position and interacts with the reverse roller based on a first predetermined time period after the sensor senses the printing medium.

13. The apparatus of claim 12, further comprising:

a main roller and a sub discharge roller provided on a path between the reverse roller and the second discharge roller,

wherein the swing roller moves to the first position away from the reverse roller based on a second predetermined time period corresponding to an amount of time for the printing medium to arrive from the reverse roller to between the reverse roller and the second discharge roller.

14. The apparatus of claim 13, further comprising:

a sub supply roller provided on a path between the reverse roller and the first discharge roller,

wherein a front end of a preceding printing medium passes through the reverse roller before a rear end of a following printing medium passes through the sub supply roller.

15. An image forming apparatus, comprising:

a main body;

an image forming unit disposed in the main body to print an image on a printing medium and feed the printed printing medium; and

a discharge unit disposed on a discharging path of the main body to discharge the printed printing medium to an outside of the main body, the discharge unit including;

a reverse roller to reverse a moving direction of the printed printing medium fed from the image forming unit;

a first discharge roller to feed the printed printing medium fed from the image forming unit to the reverse roller;

a second discharge roller to discharge the printed printing medium fed from the reverse roller to a discharge tray of the main body;

a first path extended along a first direction to receive the printing medium from the image forming unit;

a second path having an angle with the first path and connected to the first path to feed the printing medium toward the second discharge roller along a second direction;

a swing roller to swing upward to contact a trailing end of the printing medium to the reverse roller to change the moving direction of the printing medium from the first path to the second path, and

wherein the discharge unit simultaneously feeds the printing medium toward an outside of the main body through the discharge unit and receives a leading edge of a next printing medium from the image forming unit,

wherein, in a duplex printing mode, after a printing operation is performed on a first side of the printing medium and a moving direction of the printing medium engaged by the reverse roller is reversed, the printing medium is fed to a duplex-print circulation path provided between a transfer belt and a front panel of the main body and configured to feed the printing medium to the image forming unit such that a printing operation is performed on a second side of the printing medium, and

wherein, in the duplex printing mode, after the printing operation is performed on the second side of the printing medium and the moving direction of the printing medium engaged by the reverse roller is reversed, the printing medium is discharged to the discharge tray via the second discharge roller.

16. The apparatus of claim 15, wherein the first discharge roller is provided between the image forming unit and the reverse roller to feed the printing medium fed from the image forming unit.

17. A method of directing a printing medium, comprising:

in a duplex printing mode, after a printing operation is performed on a first side of a printing medium and a moving direction of the printing medium fed by a first discharge roller and engaged by a reverse roller is reversed by the reverse roller, feeding the printing medium to a duplex-print circulation path provided between a transfer belt and a front panel of a main body and configured to feed the printing medium to a print unit such that a printing operation is performed on a second side of the printing medium, and

in the duplex printing mode, after the printing operation is performed on the second side of the printing medium, a swing roller is swung upward to interact with the reverse roller, and the moving direction of the printing medium engaged by the reverse roller is reversed, discharging the printing medium to a discharge tray via a second discharge roller.

18. The method of claim 17, further comprising:

receiving the printing medium from a supply path;

after an end of the printing medium has passed from between at least two rollers of the supply path, moving the swing roller upward to press the printing medium between the swing roller and the reverse roller to change a direction of movement of the printing medium and an orientation of the rear end of the printing medium from being directed in a first direction toward the supply path to being directed in a second direction toward a discharge path located at an angle with respect to the first direction,

wherein the at least two rollers include a main roller and a first sub roller,

the first direction is directed to a location between the main roller and the first sub roller, and

the second direction is directed to a location between the main roller and a second sub roller.

19. An image forming apparatus, comprising:

a main body having a discharge tray provided at a front portion of the main body;

a print unit to perform a printing operation on a printing medium, the print unit including a plurality of developing devices and a transfer belt arranged between the plurality of developing devices and a front panel of the main body;

a reverse roller provided at a rear portion of the main body to reverse a moving direction of the printed printing medium;

a swing roller to swing upward to interact with the reverse roller;

a first discharge roller to receive the printed printing medium from the print unit and to feed the printed printing medium in a direction from the front portion to the rear portion; and

a second discharge roller to discharge the printed printing medium fed from the reverse roller to the discharge tray of the main body in a direction from the rear portion to the front portion,

wherein, in a duplex printing mode, after a printing operation is performed on a first side of a printing medium and a moving direction of the printing medium engaged by the reverse roller is reversed, the reversed printing medium is fed to a duplex-print circulation path provided between the transfer belt and the front panel of the main body and configured to feed the printing medium to the print unit to perform a printing operation on a second side of the printing medium, and

wherein, in the duplex printing mode, after the printing operation is performed on the second side of the printing medium and the moving direction of the printing medium engaged by the reverse roller is reversed, the reversed printing medium is discharged to the discharge tray via the second discharge roller,

wherein, before the printing medium is reversed by the reverse roller, the printing medium is transferred from the reverse roller toward a rear portion of the main body, and when the printing medium is reversed by the reverse roller and discharged from the reverse roller, the printing medium is directed toward the front portion of the main body.

20. The image forming apparatus according to claim 19, wherein the first discharge roller is provided between the print unit and the reverse roller to feed the printing medium fed from the print unit.

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

an intermediate discharge roller unit which is provided on a path between the first discharge roller and the second discharge roller, the intermediate discharge roller unit including a main roller, a sub discharge roller and a sub supply roller which are in contact with the main roller,

wherein the swing roller swings upward to contact the printed printing medium to the reverse roller to guide the printed printing medium fed from the first discharge roller to the second discharge roller,

wherein when a rear end of the printed printing medium passes through between the main roller and the sub supply roller, the swing roller contacts the printed printing medium to the reverse roller to reverse the moving direction of the printed printing medium, and when the rear end of the printed printing medium whose moving direction is reversed advances between the main roller and the sub discharge roller, the swing roller moves away from the reverse roller.

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

a sensor disposed between the print unit and the first discharge roller to sense an end of the printed printing medium.

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

an intermediate discharge roller unit including a main roller and a sub discharge roller provided between the second discharge roller and the reverse roller.

24. An image forming apparatus, comprising:

a main body having a discharge tray provided at a front portion of the main body;

a print unit to perform a printing operation on a printing medium, the print unit including a plurality of developing devices and a transfer belt arranged between the plurality of developing devices and a front panel of the main body;

a first discharge roller to feed the printing medium fed from the print unit;

a reverse roller to reverse a moving direction of the printing medium fed from the first discharge roller;

a swing roller to swing upward to interact with the reverse roller;

a sensor disposed between the print unit and the reverse roller to sense the printing medium; and

a second discharge roller to discharge the printing medium fed from the reverse roller to the discharge tray of the main body,

wherein, in a duplex printing mode, after a printing operation is performed on a first side of a printing medium and a moving direction of the printing medium engaged by the reverse roller is reversed, the printing medium is fed to a duplex-print circulation path provided between the transfer belt and the front panel of the main body and configured to feed the printing medium to the print unit such that a printing operation is performed on a second side of the printing medium, and

wherein, in the duplex printing mode, after the printing operation is performed on the second side of the printing medium and the moving direction of the printing medium engaged by the reverse roller is reversed, the reversed printing medium is discharged to the discharge tray via the second discharge roller,

wherein the printing medium passing through the print unit is transferred toward a rear portion of the main body during a predetermined period of time after being sensed by the sensor, and the printing medium, after the predetermined period of time has elapsed, is reversed by the reverse roller, transferred to the front portion of the main body, and selectively guided to the discharge tray or the duplex-print circulation path.

25. The image forming apparatus according to claim 24, wherein the first discharge roller is provided between the print unit and the reverse roller to feed the printing medium fed from the print unit.

26. The image forming apparatus according to claim 24, wherein a rear end of the printing medium is sensed by the sensor.

27. An image forming apparatus, comprising:

a main body having a discharge tray provided at a front portion of the main body;

a print unit to perform a printing operation on a printing medium, the print unit including a plurality of developing devices and a transfer belt arranged between the plurality of developing devices and a front panel of the main body;

a reverse roller provided at a rear portion of the main body to reverse a moving direction of the printing medium;

a swing roller to swing upward to interact with the reverse roller;

a first discharge roller to feed the printing medium fed from the print unit in a direction from the front portion to the rear portion;

a second discharge roller to discharge the printing medium fed from the reverse roller to the discharge tray of the main body in a direction from the rear portion to the front portion; and

a sensor disposed between the print unit and the reverse roller to sense a portion of the printing medium,

wherein, in a duplex printing mode, after a printing operation is performed on a first side of a printing medium and a moving direction of the printing medium engaged by the reverse roller is reversed, the reversed printing medium is fed to a duplex-print circulation path provided between the transfer belt and the front panel of the main body and configured to feed the printing medium to the print unit to perform a printing operation on a second side of the printing medium, and

wherein, in the duplex printing mode, after the printing operation is performed on the second side of the printing medium and the moving direction of the printing medium engaged by the reverse roller is reversed, the reversed printing medium is discharged to the discharge tray via the second discharge roller,

wherein, in the duplex printing mode, when a predetermined time elapses after the sensor senses the portion of the printing medium, the moving direction of the printing medium is reversed by the reverse roller.

28. The image forming apparatus according to claim 27, wherein the first discharge roller is provided between the print unit and the reverse roller to feed the printing medium fed from the print unit.

29. The image forming apparatus according to claim 27, wherein the portion of the printing medium sensed by the sensor corresponds to a rear end of the printing medium.