Patent Grant
8433234
This application claims priority under 35 U.S.C. ยง119(a) from Korean Patent Application No. 2007-0090291, filed on Sep. 6, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present general inventive concept relates to an image forming apparatus, and more particularly, to an image forming apparatus having an improved printing medium feeding path.
2. Description of the Related Art
A conventional image forming apparatus is an apparatus that prints an image on a printing medium, e.g., paper, according to an input image signal. As one type of the image forming apparatus, an electrophotographic image forming apparatus is configured such that a light beam is scanned to a photosensitive member charged to a predetermined electric potential to form an electrostatic latent image on an outer peripheral surface of the photosensitive member, the electrostatic latent image is developed into a toner image by adhering a toner to the electrostatic latent image, and the toner image is transferred and fused onto paper. The printed paper is discharged to the outside of a housing of the image forming apparatus by discharge rollers.
The conventional image forming apparatus includes a printing medium feeding unit to supply a printing medium, a printing unit to print an image of letters or pictures on the printing medium supplied from the printing medium feeding unit, and a printing medium discharge unit to discharge the printed printing medium.
In the conventional image forming apparatus as constituted above, a shape of a printing medium feeding path is determined dependent within structures of the printing medium feeding unit, the printing unit and the printing medium discharge unit and arrangement of components of the respective units. The printing medium feeding path of the image forming apparatus is generally shaped in an L-type, a C-type, an S-type, or the like. The image forming apparatus can be classified as a front-in-front-out (FIFO) type or a front-in-side-out (FISO) type according to supplying and discharging directions of the printing medium.
However, the above conventional image forming apparatus is configured such that the printed printing medium is discharged to a printing medium discharge tray while a printed surface of the printing medium is directed upward. Therefore, when a plurality of sheets of printing media are printed, the printed pages are arranged in a reverse order, which inconveniences a user having to manually arrange the printed pages in a correct order.
To solve such inconveniences, the discharge unit includes a first discharge roller which conveys the printed paper rearward from the printing unit provided in a front portion of the image forming apparatus, a reverse roller which reverses the moving direction of the paper, which is conveyed by the first discharge roller, from the rearward to the forward, and a second discharger roller which discharges the printed paper, whose moving direction has been reversed, to the outside. Thereby, the printed paper is discharged while the printed surface of the paper is directed in a down direction.
Because the printing medium is picked up rearward from the printing medium feeding cassette and conveyed forward to be printed, and then the printed printing medium is discharged to the discharge tray provided at the front portion of the image forming apparatus, the above-described conventional FIFO type image forming apparatus has an advantage of easy feeding and retrieving of the printing medium.
However, in the above-described conventional image forming apparatus, the reverse roller should be rotated sequentially in a forward direction and a reverse direction in order to perfectly discharge a sheet of printed paper to the outside. Thus, in a case where a plurality sheets of printed paper are intended to be discharged successively, at least until the preceding sheet of paper to be discharged passes away from the reverse roller, the following sheet of paper to be discharged should be kept in a standby state. If increasing a discharge speed, there is a problem such that paper jams occur in the discharge unit.
Also, because the conventional image forming apparatus is provided with a motor to drive the reverse roller, in addition to a motor to drive the first and second discharge rollers, manufacturing cost is increased, and the discharge unit has a large bulky size.
The present general inventive concept provides an image forming apparatus capable of preventing jams in a paper discharge device even when increasing a discharge speed in a discharge path, through which a printed printing medium is discharged in such a state that a printed surface of the printing medium is directed in a downward direction.
The present general inventive concept also provides an image forming apparatus capable of driving a paper discharge device by use of a single motor.
The present general inventive concept also provides an image forming apparatus having a compact overall size.
Additional aspects and/or utilities of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.
The foregoing and/or other aspects and utilities of the present general inventive concept are achieved by providing an image forming apparatus comprising: a housing formed with a discharge port, a printing device mounted in the housing, a discharge reverse unit to reversely move paper passing through the printing device, and a discharge unit to convey the paper, moving reversely by the discharge reverse unit, to the discharge port. The discharge reverse unit may include a guide member to guide the paper passing through the printing device to the discharge unit, and a lifting part to lift the guide member up and down.
The discharge reverse unit may include a paper fixing part to prevent the paper on the guide member from moving away from the guide member.
The lifting part may include a driving motor, a gear part connected to the driving motor, and a cam part to lift the guide member up and down according to rotation of the gear part.
The discharge unit may include a plurality of discharge rollers. The discharge rollers may be driven by the driving motor.
The gear part may include a first gear to transmit a driving force of the driving motor, and a second gear receiving a rotational force of the first gear. The first gear may be kept in an idling state in a predetermined region of the second gear. The cam part may be interlockingly rotated with rotation of the second gear.
The image forming apparatus may further include a sensor provided in a downstream position from the printing unit to sense a moving position of the paper.
The discharge reverse unit may further include an intermittence unit to intermit rotation of the second gear.
The intermittence unit may include a locking member to intermit rotation of the second gear, and an actuator to drive the locking member.
The discharge unit may include a plurality of discharge rollers, and the guide member may further include a guide roller to convey the paper. When the guide member is lifted up, the guide roller may come into contact with any one of the discharge rollers to move the paper toward the discharge port.
The guide member may further include a roller part corresponding to the cam part to smoothly lift the guide member up and down.
The paper fixing part may press the paper to prevent the paper on the guide member from moving away from the guide member.
The image forming apparatus may further include a paper receiving part to receive a front end of the paper positioned in the discharge reverse unit.
The paper receiving part may change the moving direction of the paper to a down direction.
The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing an image forming apparatus comprising a housing formed with a discharge port; a printing device mounted in the housing, a discharge reverse unit to reversely move paper, which moves backward in the housing after passing through the printing device, forward in the housing, a discharge unit to convey the paper, moving reversely by the discharge reverse unit, to the discharge port, and a paper fixing part to prevent the paper in the discharge reverse unit from moving backward in the housing away from the discharge reverse unit.
The discharge reverse unit may include a guide member to guide the paper passing through the printing device to the discharge unit, and a lifting part to lift the guide member up and down. The lifting part may include a driving motor, a gear part connected to the driving motor, and a cam part to lift the guide member up and down according to rotation of the gear part.
The paper fixing part may press the paper to prevent the paper on the guide member from moving away from the guide member.
The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing an image forming apparatus, including a housing, a printing device to form an image on a printing medium, a conveying unit to convey the printing medium with the image and having a roller to rotate in a direction, a discharge reverse unit to receive the printing medium from a first portion of the roller of the conveying unit, and to direct the printing medium toward a second portion of the roller, and a discharge unit to discharge the printing medium with the second portion of the roller.
The discharge reverse unit may include a shaft and a guide member extended from the shaft toward the roller.
The guide member may have a first portion coupled to the shaft and a second portion to move between the first portion of the roller and the second portion of the roller.
A first path may be formed with respect to the first portion, a second path may be formed with respect to the second portion, and the first path and the second path may be formed to be opposite with respect to a line connecting the shaft and a center of the roller.
The discharge reverse unit may include a cam part to selectively rotate according to a moving direction of the printing medium, such that the cam part controls the movement of the guide roller between the first portion of the roller and the second portion of the roller.
The housing may include a discharge port located at a front portion thereof.
The image forming apparatus may further include a discharge tray to catch the printing medium after being discharged through the discharge port.
The image forming apparatus may further include a paper receiving part to receive a front end of the printing medium in an opening thereof.
The image forming apparatus may further include a paper fixing part to prevent the printing medium from falling into the paper receiving part.
The paper fixing part may include a fixing member with a first end rotatably mounted in the housing and a second end to contact a surface of the discharge reverse unit, and an elastic member to elastically bias the fixing member to press a surface of the printing medium onto the discharge reverse unit.
The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing an image forming apparatus, including a housing including a discharge port located at a front portion thereof, a printing device mounted at the front portion of the housing to form an image onto a printing medium, a conveying roller to receive the printing medium from the printing device, a paper receiving part to receive a front end of the printing medium in an opening thereof after passing through a first portion of the conveying roller, and a discharge reverse unit to reverse a movement of the printing medium toward the discharge port to discharge the printing medium by passing the printing medium through a second portion of the conveying roller, the discharge reverse unit including a cam part to selectively rotate according to a moving direction of the printing medium, and a guide member to move up and down according to the rotation of the cam part.
The cam part may rotate when the printing medium moves toward the front portion of the image forming apparatus.
The discharge reverse unit may further include a plurality of gears to control a rotation of the cam part, and a locking member to selectively allow one of the plurality of gears to move, such that the guide member moves up when the locking member allows the one of the plurality of gears to move.
The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing a method of moving a printing medium through a housing of an image forming apparatus, the method including passing the printing medium through a printing device at a front portion of the image forming apparatus to print an image on a first side thereof, moving the printing medium toward a back portion of the housing across a discharge reverse unit, such that a paper fixing part prevents the printing medium from moving away from the discharge reverse unit, and reversing the movement of the printing medium to discharge the printing medium out the front portion of the image forming apparatus.
The method may further include guiding the printing medium through the printing device to the discharge unit using a guide member, and moving the guide member up and down according to a direction in which the printing medium is traveling.
The guide member may be moved up when the printing medium moves toward the front portion of the image forming apparatus, and the guide member may be moved down when the printing medium moves toward the back portion of the image forming apparatus.
These and/or other aspects and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below to explain the present general inventive concept by referring to the figures.
As illustrated in
A front cover 11 is mounted to the front portion of the housing 10 to open and close a front surface 10a of the housing 10. The front cover 11 is provided with a hinge part 12 at a lower end so as to rotate on the hinge part 12. A discharge tray 13 is provided on an upper portion of the housing 10, onto which the printed paper is discharged and stacked. The discharge port 14 is provided at the rear of the discharge tray 13, through which the printed paper is discharged out of the housing 10 and onto the discharge tray 13.
A paper moving path 12, through which the paper moves, is defined inside the housing 10. The paper moving path 12 includes a printing path 12a, in which the printing operation is conducted while the paper passes by the developing unit 30a and the transfer unit 30b, and a duplex printing circulation path 12b, through which the one-side printed paper circulates to an upstream position of the printing device 30 to print an image also on the other side of the paper.
The paper feeding device 20 includes a feeding cassette 22 having a feeding tray 21, on which the printing medium, i.e., the paper A, is loaded, a pickup roller 23 to pick up the paper A loaded on the feeding tray 21 sheet by sheet, and a conveying roller 24 to convey the picked-up paper A toward the printing device 30. The feeding cassette 22 is removably mounted in a lower portion of the housing 10.
The developing unit 30a of the printing device 30 includes four developing cartridges 30Y, 30M, 30C and 30K, in which toners of different colors, e.g., yellow (Y), magenta (M), cyan (C) and black (K), are respectively contained. The developing cartridges 30Y, 30M, 30C and 30K are respectively provided with photosensitive bodies 31, on surfaces of which electrostatic latent images are formed by a plurality of exposure units 70. The exposure units 70 irradiate light corresponding to image information of yellow, magenta, cyan and black to the photosensitive bodies 31 of the respective developing cartridges according to a print signal.
Each of the developing cartridges 30Y, 30M, 30C and 30K includes a charge roller 32 to charge each of the photosensitive bodies 31 to a predetermined electric potential, a development roller 33 to develop the electrostatic latent image formed on each of the photosensitive bodies 31 into a toner image, and a supply roller 34 to supply the toner to the development roller 33.
The transfer unit 30b of the printing device 30 transfers the toner image developed on the photosensitive bodies 31 onto the paper A. The transfer unit 30b includes a transfer belt 35 which circulates while being in contact with the photosensitive bodies 31, a driving roller 36 to drive the transfer belt 35, a tension roller 37 to maintain a constant tensile force of the transfer belt 35, and four transfer rollers 38 to transfer the toner images developed on the respective photosensitive bodies 31 onto the paper A.
The fusing device 40 applies heat and pressure to the image transferred onto the paper A so as to fuse the image to the paper A. The fusing device 40 includes a heating roller 41 having a heat source to apply heat to the toner image-transferred paper A, and a press roller 42 mounted while opposing the heating roller 41 to maintain a constant fusing pressure with the heating roller 41.
The duplex printing device 50 conveys the one-side printed paper A to the upstream position of the printing device 30 so that the other side of the paper A may also be printed thereupon. The duplex printing device 50 includes a guide frame 51 which forms the duplex printing circulation path 12b, and a series of duplex printing conveying rollers 52 mounted in the duplex printing circulation path 12b to convey the paper A.
The scanning device 60 is mounted above the housing 10. The scanning device 60 includes a main body 61, in which electronic components including an image sensor (not illustrated) are mounted, and an upper cover 62 which covers an upper surface of the main body 61. The upper cover 62 is coupled to the main body 61 by a first hinge part 63, and rotates on the first hinge part 63 to open and close the upper surface of the main body 61.
An extraction space 15 is formed between the main body 61 of the scanning device 60 and the discharge tray 13 provided on the upper portion of the housing 10. A user can extract the printed paper A, which is stacked on the discharge tray 13, through the extraction space 15. Since the scanning device 60 is rotatably coupled to the housing 10 by a second hinge part 64, if the user rotates the scanning device 60 backward on the second hinge part 64, the user can more easily extract the paper from the discharge tray 13.
The printing device 30, the fusing device 40, the printing path 12a and the duplex printing circulation path 12b are disposed near the front surface 10a of the housing 10. The front surface 10a of the housing 10 can be opened so that the user can get access to the printing device 30 and the fusing device 40 or the paper moving paths 12a and 12b. Thus, when a user desires to replace expendable components (e.g., toner, rollers, etc) of the printing device 30 or the fusing device 40, or remove paper jammed in the paper moving paths 12a and 12b, the user can carry out the replacing or removing operations at a front portion of the image forming apparatus. Accordingly, convenience of use is increased. Moreover, an additional space to perform the replacing or paper-jam-removing operations is not required, and thus the user can more efficiently use the space around the image forming apparatus.
When the printing device 30, the fusing device 40 and the paper moving paths 12a and 12b are disposed near the front surface 10a of the housing 10 as described above, the paper A passing through the fusing device 40 moves toward a rear surface 10b of the housing 10. Accordingly, the paper discharge device 100 reverses the moving direction of the paper, which moves toward the rear surface 10b of the housing 10, and then discharges the paper to the front of the housing 10.
As illustrated in
During the paper discharge process, the conveying unit 110 conveys the paper passing through the fusing device 40 to the discharge reverse unit 120. The conveying unit 110 includes a conveying roller 111 which is rotated by receiving power from a driving source (not illustrated), and a conveying idle roller 112 which is rotated in contact with the conveying roller 111.
A sensor 101 is mounted between the fusing device 40 and the conveying unit 110, to sense the position of the conveyed paper A.
The discharge reverse unit 120 reverses the paper A, which moves backward after passing through the fusing device 40, to the front. The discharge reverse unit 120 is mounted in the downstream position from the conveying unit 110 in the paper moving path 12.
As illustrated in
The guide member 210 is formed with a shaft part 211 at a second end portion thereof so that the guide member 210 can be rotatably mounted in the housing 10. Guide rollers 212 are mounted to the guide member 210, which come into contact with a first discharge roller 141 (which will be described later) when the guide member 210 is lifted up, to move the paper A on the guide member 210 to the discharge port 14.
Roller parts 213 are mounted to the first end portion of the guide member 210, which are in contact with cam parts 225 of the lifting part 220 (which will be described later), so as to smoothly lift the guide member 210 up and down according to the rotation of the cam parts 225.
The lifting part 220 includes a driving motor 221, gear parts 222 and 223 connected with the driving motor 221, a rotating shaft part 224 coupled to a second gear 223 of the gear parts 222 and 223 to be rotated according to the rotation of the second gear 223, and the cam parts 225 fixed to the rotating shaft part 224 to be interlockingly rotated with the second gear 223.
A plurality of gears may be connected between the driving motor 221 and a first gear 222 of the gear parts 222 and 223. Although not illustrated in the drawings, a plurality of gears may be connected between the driving motor 221 and the discharge unit 140 so that the discharge unit 140 can be driven by the driving motor 221. Since methods of driving a plurality of discharge rollers (including the discharge roller 141 and a second discharge roller 142) of the discharge unit 140 by use of the single driving motor 221 is already well known, explanation thereof will be omitted.
By connecting the gears to the driving motor 221, which drives the plurality of discharge rollers, to drive the discharge reverse unit 120, the entire paper discharge device 100 can be driven by use of the single driving motor 221.
The second gear 223 is provided with an idling region 223a (refer to
The cam parts 225 fixed to the rotating shaft part 224 are rotated according to the rotation of the second gear 223. Since the cam parts 225 are eccentrically fixed to the rotating shaft part 224, when the cam parts 225 rotate, the roller parts 213 of the guide member 210, which are kept in contact with the cam parts 225, roll on the outer surfaces of the cam parts 225, thereby lifting the guide member 210 up and down.
As illustrated in
Accordingly, when the locking member 231 is positioned in the locking position, the first gear 222 idles in contact with the idling region 223a of the second gear 223, and the rotational force of the first gear 222 is not transmitted to the second gear 223.
When the locking state by the locking member 231 is released, the second gear 223 initially rotates by the frictional force by the rotation of the first gear 222, and then the first gear 222 and the second gear 223 are tooth-engaged with each other. Thereby, the rotational force of the first gear 222 is transmitted to the second gear 223, and thus the second gear 223 is rotated.
When the second gear 223 is rotated once and the first gear 222 comes into contact with the idling region 223a, if the actuator 232 is turned off, the locking member 231 moves to the locking position, and thus the rotation of the second gear 223 is restrained.
During the rotation of the second gear 223, the cam parts 225 are interlockingly rotated once with the second gear 223, and accordingly the guide member 210 is lifted up and down by the rotation of the cam parts 225.
As illustrated in
The paper A passing through the guide member 210 moves to the rear of the housing 10 until the rear end of the paper A passes entirely through the conveying roller 111. At this time, the front end of the paper A has passed beyond the guide member 210, which may cause the paper A to fall from the guide member 210 by its own weight into the paper receiving part 130.
In order to prevent the falling of the paper A, the fixing member 151 of the paper fixing part 150 presses the paper A to the upper surface of the guide member 210.
The paper receiving part 130, as illustrated in
The discharge unit 140, as illustrated in
Hereinafter, an operation of the image forming apparatus according to an embodiment of the present general inventive concept will be described with reference to the accompanying drawings.
First, the printing operation and the paper discharging operation of the image forming apparatus according to an embodiment of the present general inventive concept will be explained. As illustrated in
The paper A, which is picked up by the pickup roller 23, is attached to the transfer belt 35, and is conveyed at the same speed as the traveling speed of the transfer belt 35. At this time, voltage having a polarity opposite to the toner adhered to the respective photosensitive bodies 31 is applied to the respective transfer rollers 38, and the toner images on the photosensitive bodies 31 are transferred onto the paper A. Accordingly, the toner images of yellow, magenta, cyan and black formed on the respective photosensitive bodies 31 are overlappingly transferred sequentially onto the conveyed paper A. As a result, a color toner image is formed on the paper A.
The toner image transferred onto the paper A is fused thereon while passing through the fusing device 40. The paper A having passed through the fusing device 40 passes by the sensor 101 as illustrated in
The paper A conveyed onto the guide member 210 moves to the rear of the housing 10 until the rear end of the paper passes entirely through the conveying roller 111, as illustrated in
When the sensor 101 senses that the paper A is conveyed to the discharge reverse unit 120, after a predetermined time to permit the rear end of the paper A to pass through the conveying roller 111, the actuator 232 is operated to move the locking member 231 to the releasing position. Thereby, the second gear 223 is initially rotated by the frictional force by the rotation of the first gear 222, and then the first gear 222 and the second gear 223 are tooth-engaged with each other. Accordingly, the second gear 223 is rotated, and the cam parts 225 are interlockingly rotated with the second gear 223.
While the second gear 223 is rotated once, the roller parts 213 of the guide member 210 roll on the outer surfaces of the cam parts 225 by the rotation of the cam parts 225. As a result, the guide member 210 is lifted up and down.
When the guide member 210 is lifted up, as illustrated in
When the guide member 210 is lifted down after one rotation of the second gear 223, the actuator 232 is turned off. Thereby, the locking member 231 is moved to the region between the teeth of the second gear 223, and restrains the rotation of the second gear 223. At this time, since the teeth of the first gear 222 are in contact with the idling region 223a of the second gear 223, the rotational force of the first gear 222 is not transmitted to the second gear 223, and the first gear 222 is kept in an idling state.
After the guide member 210 is lifted down, the following sheet of paper A is conveyed onto the guide member 210, and the above-described operation is repeated.
As described above, immediately after the preceding sheet of paper A is conveyed to the discharge unit 140 from the guide member 210, which has been lifted up, the guide member 210 is lifted down so that the following sheet of paper A can be conveyed onto the guide member 210. Accordingly, simultaneously with moving the preceding sheet of paper A by the discharge unit 140, the following sheet of paper A can be conveyed onto the guide member 210. As a result, the interval between the paper sheets to be discharged is shortened, and thus time taken to discharge the paper sheets can be decreased.
In the above description, the present general inventive concept has been explained with reference to the electrophotographic type color multifunction printer. However, the features of the present general inventive concept can also be applied to other image forming apparatuses, such as ink-jet printers, copying machines, fax machines, etc.
As apparent from the above description, the image forming apparatus according to the present general inventive concept can prevent the paper on the guide member from falling away from the guide member due to its own weight by use of the paper fixing part.
Further, since the discharge unit and the discharge reverse unit can be driven simultaneously by use of the single motor, manufacturing costs can be demonstrated.
Further, the discharge reverse unit can be simply constituted in such a manner that the guide member is lifted up and down by use of the gear part and the cam part.
Still further, since the paper receiving part, i.e., the space allowing the movement of the front end of the paper before the moving direction of the paper is reversed, is formed small, the overall size of the image forming apparatus can be compact.
Although a few embodiments of the present general inventive concept have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2007-0090291 | Sep 2007 | KR | national |
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| Number | Date | Country | |
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| 20090067909 A1 | Mar 2009 | US |
