This application claims the benefit of Korean Application No. 2007-39369, filed Apr. 23, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
Aspects of the present invention relate to an image forming apparatus, and more particularly, to a lever assembly used in the image forming apparatus, the image forming apparatus having the same, and a solenoid used in the lever assembly.
2. Description of the Related Art
Generally, an image forming apparatus has a pickup roller that picks up printing media one by one from a printing media cassette. A pickup roller control unit controls the pickup roller to rotate so that the pickup roller picks up the loaded printing media one by one to feed an image forming unit according to a signal from a controller of the image forming apparatus.
The conventional pickup roller control unit uses a solenoid as an actuator to control rotation of the pickup roller according to the signal from the controller of the image forming apparatus. Here, “to control rotation of the pickup roller” refers to rotating or stopping the pickup roller according to the signal from the controller of the image forming apparatus.
Generally, in the conventional pickup roller control unit, a connecting part or a lever that holds a rotation shaft of the pickup roller to stop the pickup roller according to motion of the solenoid is disposed between the solenoid and the rotation shaft of the pickup roller. As a result, in the conventional pickup roller control unit, the controller of the image forming apparatus controls the solenoid, thereby controlling the rotation of the pickup roller.
In the conventional pickup roller control unit, the connecting part or lever to hold the rotation shaft of the pickup roller and the solenoid to actuate the connecting part or lever are separately formed from each other, and disposed directly on a main body frame of the image forming apparatus. Because the conventional pickup roller control unit and the solenoid are separately installed on the main body frame of the image forming apparatus, it is difficult to install the pickup roller control unit on the image forming apparatus.
Additionally, because the conventional pickup roller control and the solenoid are separately installed on the main body frame of the image forming apparatus, if a portion of the main body frame in which the lever or connecting part is installed is not precisely machined, the relative position between the lever or connecting part and the solenoid may deviate from the designed positions. When the relative position between the lever or connecting part and the solenoid deviates, the solenoid cannot operate smoothly. Also, when the relative position between the lever or connecting part and the solenoid deviates from the designed positions, the pulling force with which the solenoid pulls the lever or connecting part may decrease.
Aspects of the present invention have been developed in order to overcome the above drawbacks and other problems associated with the conventional arrangement. Aspects of the present invention provide a solenoid assembly that has been adapted to be assembled easily and to operate smoothly, an image forming apparatus having the same, and a solenoid used in the solenoid assembly.
This aspect and/or other features of the present invention can substantially be achieved by providing a lever assembly including a lever; a solenoid to actuate the lever where the solenoid is fixed to at one side of the lever; and a supporting plate where the lever is rotatably disposed. The lever may be rotatably supported by a lever axis formed on the supporting plate.
The solenoid includes: a plunger connected with the lever; a coil disposed to wrap around the plunger and to pull the plunger when electric power is applied to the coil; a frame to which the coil is attached, where the bottom plate of the frame has a plunger hole through which a second end of the plunger passes. One side plate of the frame may be extended to form the supporting plate in one single part with the frame.
The frame may be formed in a substantially flat U shape to enclose the coil, and one side plate of the substantially flat U shape of the frame may be extended to form the supporting plate. The frame may include a holding cap to hold both top ends of the substantially flat U shape. Also, the frame may include a projection port to project from the bottom plate of the frame around the plunger hole.
The lever assembly may have an elastic member that is disposed at the plunger and a plurality of attachment holes that is formed at the supporting plate.
According to another aspect of the present invention, an image forming apparatus includes: a pickup roller shaft on which a pickup roller is disposed; a pickup gear disposed at one end of the pickup roller shaft with a pickup cam; a lever assembly disposed at one side of the pickup cam to control rotation of the pickup gear, the lever assembly including a lever and a solenoid to actuate the lever; and a supporting plate on which the lever is rotatably disposed and where the solenoid is connected to one side of the lever; and an image forming unit to form images on a printing medium that is picked up by the pickup roller.
According to another aspect of the present invention, a solenoid includes: a plunger; a coil disposed to wrap around the plunger and to pull the plunger when electric power is applied to the coil; a frame to which the coil is attached, with a hole in the bottom plate of the frame through which a second end of the plunger passes; and a projection port to project from the bottom plate of the frame around the plunger hole. The pulling force distance may be extended to as much as the height of the projection port.
Additional aspects and/or advantages of the invention 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 invention.
These and/or other aspects and advantages of the invention 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 the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.
Referring to
Referring now as well to
An elastic member 127 is disposed between a portion near the first end 121b of the plunger 121 and the frame 130 of the solenoid 120. The elastic member 127 elastically restores the plunger 121 to a position projected from the frame 130 of the solenoid 120. As a result, when electric power is applied to the coil 123, the plunger 121 is moved toward the coil 123 (in the direction of arrow A in
The coil 123 is disposed to wrap around the plunger 121. When electric power is applied to the coil 123, the coil 123 is configured to pull the plunger 121 toward itself, that is, in the direction of arrow A in
The frame 130 forms the external appearance of the solenoid 120 and holds the coil 123. In this embodiment, as illustrated in
A plunger hole 133a is formed in the bottom plate 133 of the frame 130 through which a second end 121c of the plunger 121 can pass. A projection port 134 may be formed around the plunger hole 133a to project outside from the bottom plate 133 of the frame 130. The projection port 134 is formed integrally with the frame 130. The projection port 134 may be formed by a burring process when the plunger hole 133a of the frame 130 is machined using a press machine. The projection port 134 that is formed on the bottom plate 133 of the frame 130 allows the pulling force distance to be extended. Here, the pulling force distance refers to the distance through which the pulling force operates for the coil 123 pulling the plunger 121. For example, when a dimension of height H (see
Here, the pulling force of the coil 123 refers to the magnetic force that is generated in the coil 123 when electric power is applied to the coil 123, and pulls the plunger 121 in the direction of arrow A in
Therefore, in this aspect of the present invention, in order to extend the distance where the pulling force of the coil 123 operates, that is, the pulling force distance, the projection port 134 is formed around the plunger hole 133a of the bottom plate 133 of the frame 130 through which the second end 121c of the plunger 121 passes. The height H of the projection port 134 may be any dimension suitable for the purpose described herein. Furthermore, in this embodiment, the projection port 134 is formed on the bottom plate 133 of the frame 130. Alternatively, to extend the pulling force distance, the bottom plate 133 of the frame 130 may be formed to be thicker than that of the bottom plate 133 of the frame 130 as described in the above embodiment, up to the height H of the above-described projection port 134. However, in this case, the frame 130 must be made of a thicker material so that the weight of the lever assembly 100 becomes too heavy.
The supporting plate 140 supports the lever 110 to rotate the lever axis 115 and the solenoid 120. That is, the lever axis 115, the lever 110 and the solenoid 120 are disposed on the same supporting plate 140 so that the relative position between the rotation center of the lever 110, that is, the center of the lever axis 115, and the solenoid 120 is determined by the supporting plate 140. Therefore, the relative position between the rotation center of the lever 110 and the solenoid 120 is not affected by the exact dimensions of the main body frame 201 of the image forming apparatus 200 (see, particularly,
The supporting plate 140 may be formed as a separate part. Alternatively, the supporting plate 140 may be formed as one single part along with the frame 130 of the solenoid 120. In the embodiment shown in
The lever axis 115 is disposed on the supporting plate 140. The lever hole 114 that is formed at the second end of the lever 110 is placed on the lever axis 115. Therefore, the lever 110 can rotate on the lever axis 115. Also, a plurality of connecting holes 141 is formed on the supporting plate 140 where the connecting holes 141 are used to connect the supporting plate 140 to the main body frame 201 of the image forming apparatus 200.
Hereinafter, operation of the lever assembly 100 according to this aspect of the present invention will be explained with reference to
When the plunger 121 moves in the direction of arrow A, the lever 110 connected to the first end 121b of the plunger 121 rotates on the lever axis 115 in the clockwise direction. When the plunger 121 moves entirely inside the coil 123 (as illustrated in
After the hook 111 of the lever 110 leaves the hooking projection 215a of the pickup cam 215, the controller of the image forming apparatus 200 turns off the electric power to be applied to the coil 123. Then, the plunger 121 is moved in the reverse direction of arrow A as a result of the elasticity of the elastic member 127 so as to be restored to the original position near the pickup cam 215. When the pickup gear 213 continues to rotate, the hooking projection 215a of the pickup cam 215 is hooked on the hook 111 of the lever 110. When the hooking projection 215a of the pickup cam 215 is hooked on the hook 111 of the lever 110, the pickup gear 213 stops rotating.
Therefore, with the lever assembly 100 formed according to this aspect of the present invention, when the lever 110 and the solenoid 120 are disposed on the same supporting plate 140, the solenoid 120 can smoothly operate the lever 110, unaffected by the exact measurements of the main body frame 201 of the image forming apparatus 200.
Hereinafter, the image forming apparatus 200 having the lever assembly 100 according to an embodiment of the present invention will be explained.
Referring to
The printing medium feeding unit 210 picks up printing media P one by one and feeds a picked up printing medium P to the conveying roller unit 220. The printing medium feeding unit 210 includes a printing medium cassette 285 in which a plurality of printing media P is loaded, a pickup roller 212 that is disposed at a leading end of the printing medium cassette 285, and the lever assembly 100 that controls rotation of the pickup roller 212 so that the controller of the image forming apparatus 200 can intermittently rotate the pickup roller 212.
The pickup roller 212 is disposed along the pickup roller shaft 211, and the pickup gear 213 is disposed at one end of the pickup roller shaft 211. The pickup cam 215 is disposed at one side surface of the pickup gear 213 to control rotation of the pickup roller 212 together with the lever assembly 100. Alternatively, the pickup cam 215 may be formed integrally with the pickup gear 213 at one side surface of the pickup gear 213. The pickup cam 215 has the hooking projection 215a (see
The pickup gear 213 is disposed to engage with the pickup driving gear 217 that is disposed at one side of the pickup gear 213. The pickup driving gear 217 receives power from a driving motor (not illustrated) in order to rotate.
The lever assembly 100 is disposed at one side of the pickup cam 215 to control the rotation of the pickup roller 212 according to a signal from the controller of the image forming apparatus 200. The lever assembly 100 includes the lever 110, the solenoid 120, and the supporting plate 140. The structure and operation of the lever assembly 100 are not explained in detail here since they were previously described above in detail.
The conveying roller unit 220 includes at least one pair of conveying rollers, and conveys the printing medium P to be picked up by the pickup roller 212 of the printing medium feeding unit 210 to the image forming unit 230. The image forming unit 230 forms images on the printing medium P, and includes a light exposure unit 240, a developing cartridge 250, and a transferring roller 260.
The developing cartridge 250 has a housing 251, and a photosensitive medium 252 and a developing roller 253 that are rotatably disposed inside the housing 251. The developing cartridge 250 develops electrostatic latent images, which are formed on the photosensitive medium 252 by laser beam emitted from the light exposure unit 240, into toner images.
The transferring roller 260 is rotatably disposed to contact the photosensitive medium 252 below the developing cartridge 250, and causes the toner images on the photosensitive medium 252 to be transferred onto the printing medium P conveyed from the printing medium feeding unit 210. The fixing unit 270 includes a pressure roller and a heat roller, and applies high heat and high pressure to the printing medium P passing through between the pressure and heat rollers so that the transferred toner images are fixed onto the printing medium P. The discharging unit 280 discharges the printing medium P, which has the images fixed thereon when passing through the fixing unit 270, to the outside of the image forming apparatus 200.
Hereinafter, operation of the image forming apparatus 200 with the above-described structure will be explained with reference to
The laser beam emitted from the light exposure unit 240 enters the photosensitive medium 252 of the developing cartridge 250 to form electrostatic latent images corresponding to the printing data on a surface of the photosensitive medium 252. The electrostatic latent images on the photosensitive medium 252 are developed into toner images with toner that the developing roller 253 disposed inside the developing cartridge 250 supplies. Also, when receiving the printing order, the controller of the image forming apparatus 200 operates the printing medium feeding unit 210 to pick up a printing medium P from the loaded printing media P and to feed the picked up printing medium P to the conveying roller unit 220.
The process in which the printing medium feeding unit 210 picks up one printing medium P will now be described in detail. When receiving the printing order, the controller of the image forming apparatus 200 applies electric power to the coil 123 of the solenoid 120 of the lever assembly 100. When the electric power is applied to the coil 123, the plunger 121 is pulled toward the coil 123 so that the lever 110 rotates on the lever axis 115.
The lever 110 rotates toward the solenoid 120 so that the hook 111 of the lever 110 leaves the hooking projection 215a of the pickup cam 215. When the hook 111 of the lever 110 leaves the hooking projection 215a, the pickup gear 213 that is engaged with the pickup driving gear 217 rotates. When the pickup gear 213 rotates, the pickup roller 212 disposed on the same shaft 211 as the pickup gear 213 also rotates. When the pickup roller 212 rotates, one printing medium P is picked up from the printing medium cassette 285 and fed to the conveying roller unit 220.
When the plunger 121 is completely pulled to the coil 123 as illustrated in
When the pickup roller 212 continues to rotate, the hooking projection 215a of the pickup cam 215 is hooked on the hook 111 of the lever 110. When the hooking projection 215a of the pickup cam 215 is hooked on the hook 111 of the lever 110, the pickup roller 212 stops rotating.
After that, when the controller of the image forming apparatus 200 applies electric power to the coil 123 of the solenoid 120, the pickup roller 212 makes one revolution to again pick up one printing medium P. The printing medium P that is picked up by the pickup roller 212 passes through the conveying roller unit 220 and enters between the transferring roller 260 and the photosensitive medium 252 of the developing cartridge 250. When the printing medium P enters between the photosensitive medium 252 of the developing cartridge 250 and the transferring roller 260, the toner images on the photosensitive medium 252 are transferred onto the printing medium P. The printing medium P with the toner images transferred thereon moves to the fixing unit 270. When the printing medium P passes through between the pressure and heat rollers of the fixing unit 270, the toner images are fixed onto the printing medium P. The printing medium P with the toner images fixed thereon is discharged to outside the image forming apparatus 200 via the discharging unit 280.
In the above-description, an electro photographic image forming apparatus is described as an apparatus in which the lever assembly according to aspects of the present invention can be used; however, this should not be considered as limiting. Alternatively, the lever assembly according to aspects of the present invention can be used in inkjet printers. In other words, the lever assembly according to aspects of the present invention can be used in various image forming apparatuses such as copiers, composite apparatuses, facsimiles, etc. that have a function intermittently picking up printing media one by one.
With the lever assembly according to aspects of the present invention and the image forming apparatus having the same as described above, since the lever and solenoid are disposed on the same supporting plate, the lever can smoothly operate regardless of the exact measurements of the main body frame of the image forming apparatus.
Also, with the image forming apparatus according to aspects of the present invention, the lever and solenoid are assembled to form the lever assembly, and then the lever assembly is assembled on the main body frame of the image forming apparatus. Therefore, assembly of the image forming apparatus according to aspects of the present invention is more convenient than that of a conventional image forming apparatus configured so that the lever and solenoid are directly disposed at the main body frame thereof.
Additionally, with the solenoid according to aspects of the present invention, the range of the pulling force distance thereof can be adjusted by design of the height of the projection port that is formed on the bottom plate of the frame so that it is easy to manufacture the solenoid. Furthermore, it is not required to use a thick material in order to manufacture the frame of the solenoid so that weight of the solenoid may be reduced.
Although a few embodiments of the present invention 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 invention, the scope of which is defined in the claims and their equivalents.
Number | Date | Country | Kind |
---|---|---|---|
10-2007-39369 | Apr 2007 | KR | national |
Number | Name | Date | Kind |
---|---|---|---|
3815900 | Schulze | Jun 1974 | A |
3848907 | Shiurila | Nov 1974 | A |
4216454 | Ohtani et al. | Aug 1980 | A |
4529188 | Sturnick | Jul 1985 | A |
5358230 | Ikemori et al. | Oct 1994 | A |
5876073 | Geringer et al. | Mar 1999 | A |
6070867 | Tsurumi et al. | Jun 2000 | A |
6624733 | Swenson, Jr. | Sep 2003 | B1 |
7270323 | Somemiya | Sep 2007 | B2 |
20050189698 | Somemiya | Sep 2005 | A1 |
20060038645 | Hoffman | Feb 2006 | A1 |
Number | Date | Country |
---|---|---|
1552948 | Jul 2005 | EP |
2195614 | Apr 1988 | GB |
57-145735 | Sep 1982 | JP |
58-6856 | Jan 1983 | JP |
59-92835 | May 1984 | JP |
62-100334 | May 1987 | JP |
62-215439 | Sep 1987 | JP |
1-233712 | Sep 1989 | JP |
7-106799 | Nov 1995 | JP |
2002-240971 | Aug 2002 | JP |
Entry |
---|
Machine translation of JP 2002-240971. |
Korean Notice of Preliminary Rejection dated May 4, 2011 to Korean Patent Application No. 10-2007-0039369. |
Partial European Search Report, mailed Oct. 4, 2010, in corresponding European Application 08101618.0 (5 pp.). |
Number | Date | Country | |
---|---|---|---|
20080257100 A1 | Oct 2008 | US |