US20060180982A1

US20060180982A1 - Air suction feeding device and image forming apparatus having the same

Info

Publication number: US20060180982A1
Application number: US11/207,803
Authority: US
Inventors: Jong-Sung Kim
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2004-09-24
Filing date: 2005-08-22
Publication date: 2006-08-17
Also published as: KR100565793B1

Abstract

An air suction feeding device which attracts a printing medium through air suction and transports the printing medium while maintaining the adhesion state of the printing medium. The air suction feeding device includes a feed roller which is configured with a shaft and a plurality of rollers arranged on the shaft to transport the printing medium through rotation. Air suction openings are arranged between the rollers to adhere one side of the printing medium onto the surfaces of the rollers and an air suction unit sucks air from the air suction openings.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. § 119 from Korean Patent Application No. 2004-76997, filed on Sep. 24, 2004, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to a printing medium feeding apparatus for use in an image forming apparatus. More specifically, the present invention relates to an air suction feeding device which attracts an uppermost sheet of paper with air suction to adhere the paper to the surface of a feed roller.
2. Description of the Related Art
In general, an image forming apparatus includes a paper feeding unit for feeding printing media such as sheets of paper one after another, an image forming unit for forming an image onto a printing medium provided from the paper feeding unit, and a feeding unit for transporting the printing medium to enable the image forming unit to form an image thereon and release the printing medium bearing the image out of the image forming apparatus.
In the case of an electrophotographic image forming apparatus such as a laser printer, the image forming unit includes photosensitive bodies on which electrostatic latent images of printing data are formed and developed by developers, a transfer device for transferring the images formed on the surfaces of the photosensitive bodies onto a printing medium, and a fusing device for fusing the transferred images onto the printing medium. The feeding unit is configured with a plurality of feeding devices arranged between the paper feeding unit and the transfer device, between the transfer device and the fusing device, and between the fusing device and an outlet, respectively, and transports the printing medium between the devices.
A typical example of the feeding device is illustrated in FIG. 1. As shown in FIG. 1, the feeding device 1 includes a drive roller 3 connected to a motor (not shown) for rotation, an idler roller 5 rotating in contact with the drive roller 3, and a spring 7 for pressing the idler roller 5 against the drive roller 3. Because a predetermined level of pressure from the spring 7 is transmitted to the drive roller 3 via the idler roller 5, the drive roller 3 and the idler roller 3 rotate together. Therefore, when a printing medium 9, such as a sheet of paper, enters between the drive roller 3 and the idler roller 5, a frictional force is generated between the printing medium 9 and the rollers. The printing medium 9 is transported in the drive roller's rotational direction via the frictional force.
However, it is preferable that the feeding device 1 having a pair of rollers not be used in some cases. For example, the feeding device 1 having rollers should not be used if the top side of the paper between the transfer device and the fusing device carries an unfused image, or if it is necessary to prevent scratches on the top side of the paper.
As an attempt to resolve the above problem, an air suction feeding device for attracting the printing medium through air suction was developed. As shown in FIG. 2, the air suction feeding device 10 according to a related art includes a belt 11 having a plurality of air suction openings formed therein, a driving roller 13 and a driven roller 15 for rotating the belt 11, and an air suction unit (not shown) for generating a suction force which sucks air into air suction openings.
More specifically, a plurality of air suction openings are formed on the top surface of the belt 11, and the openings are connected to the air suction unit. The air suction unit is configured with a duct connected to the air suction openings of the belt 11, and a fan for generating a suction force to suck the air. Therefore, when the fan of the air suction unit starts, the air is sucked into the air suction openings of the belt 11 and the bottom side of a printing medium 19 on the belt 11 adheres to the belt 11 and is transported while maintaining its adhesion state. In other words, the printing medium 19 can be transported via the belt 11 without applying any force onto the top of the printing medium.
Although the air suction feeding device may solve the problem of paper feeding, it still requires having two rollers 13, 15 for rotating the belt 11. This structural feature makes the configuration more complicated and requires more space. Also, in order to suck the air from all the air suction openings formed on the circumference of the belt 11 to adhere the printing medium 19 onto the belt 11, a large capacity fan should be used.
Accordingly, there is a need for an improved air suction feeding device capable of protecting the top side of a printing medium during transport which features a relatively simple configuration and minimized size for installation into relatively small spaces.

SUMMARY OF THE INVENTION

An aspect of the present invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide an air suction feeding device capable of protecting the top side of a printing medium during transport.
It is another object of the present invention to provide an air suction feeding device featuring a relatively simple configuration and a small size, which is thereby arranged into a very small space.
It is yet another object of the present invention to provide an image forming apparatus using an air suction feeding device which is reduced in size and causes less wrap jams during the paper feeding process.
To achieve the above objects and advantages, there is provided an air suction feeding device including a feed roller comprised of a shaft and a plurality of rollers arranged on the shaft which feeds (or transports) a printing medium. A plurality of air suction openings are arranged between the rollers to adhere one side of the printing medium onto the surfaces of the rollers. Additionally, an air suction unit is provided which sucks air from the air suction openings.
In an exemplary embodiment of the present invention, the air suction openings are arranged in spaces between the rollers, being disposed on at least two sides of the shaft.
Preferably, the air suction feeding device further comprises a medium guide arranged behind the feed roller which separates the printing medium from the surfaces of the rollers. In particular, the medium guide comprises a plurality of fingers disposed between the rollers in such a manner so as to not cover the air suction openings.
Another aspect of the present invention provides an air suction feeding device including a feed roller which attracts a printing medium with air suction and feeds the printing medium. An air suction unit provides a suction force to the feed roller. A medium guide separates the printing medium from the feed roller and guides the printing medium in a predetermined direction.
Here, the feed roller includes air suction openings formed on a surface of the feed roller which attract one side of the printing medium to the surface of the feed roller through air suction. An air hole formed on one end of the feed roller and a duct arranged in the feed roller are provided to fluidly communicate the air suction openings with the air hole.
In an exemplary embodiment of the present invention, the plurality of air suction openings are formed at regular intervals along the circumferential direction of the feed roller. Also, the air suction openings are formed along the axial direction of the feed roller.
In an exemplary embodiment of the present invention, the feed roller includes a shaft and a plurality of rollers arranged at regular intervals on the shaft.
Here, the plurality of air suction openings are formed along the circumferential direction of the rollers, respectively, and the duct is formed proximal to the center of the shaft.
Yet another aspect of the present invention provides an image forming apparatus comprising a paper feeding unit which provides a printing medium one after another, an image forming unit which forms an image on the surface of the printing medium provided from the paper feeding unit, a feeding unit which transports the printing medium to enable the image forming unit to form images thereon and releases the printing medium bearing the image out of the image forming apparatus, and an air suction feeding device arranged on the feeding unit which attracts one side of the printing medium onto the feed roller through air suction and transports the printing medium while maintaining the adhesion state of the printing medium onto the feed roller.
In an exemplary embodiment of the present invention, the air suction feeding device includes a feed roller with a shaft and a plurality of rollers arranged on the shaft which transports the printing medium. A plurality of air suction openings are arranged between the rollers to adhere one side of the printing medium onto the surfaces of the rollers. An air suction unit sucks air from the air suction openings.
In an exemplary embodiment of the present invention, the image forming apparatus further includes a transfer device and a fusing device. The air suction feeding device is arranged between the transfer device and the fusing device.
Also, the air suction feeding device can be arranged on an outlet to release the printing medium outside.
As described above, the air suction feeding device of the exemplary embodiments of the present invention attracts the bottom side of the printing medium through air suction and transports the printing medium while maintaining the adhesion thereof. Therefore, the top side of the printing medium bearing an image can be well protected.
The air suction feeding device of the exemplary embodiments of the present invention can be used in a small space because it has a simple structure compared with conventional air suction feeding devices using a belt, and occupies a relatively small space for installation.
In contrast to conventional air suction feeding devices which use a belt, the air suction feeding device of the exemplary embodiments of the present invention do not use a belt. Therefore, a small capacity fan can be used.
By applying the air suction feeding device of the exemplary embodiments of the present invention to an image forming apparatus, it becomes possible to reduce the size of the image forming apparatus and avoid wrap jams (or paper jams) during the paper feeding process.
Other objects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of certain embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a conceptual diagram illustrating a conventional feeding device;
FIG. 2 is still a conceptual diagram illustrating a conventional air suction feeding device;
FIG. 3 is a perspective view of an air suction feeding device according to an embodiment of the present invention;
FIG. 4 is a side cross-sectional view of the air suction feeding apparatus of FIG. 3;
FIG. 5 is a perspective view of an air suction feeding device according to another embodiment of the present invention;
FIG. 6 is a cross-sectional view of a feed roller in the air suction feeding device of FIG. 5;
FIG. 7 is a perspective view of another embodiment of a feed roller in the air suction feeding device of FIG. 5;
FIG. 8 is a conceptual diagram illustrating an image forming apparatus having an air suction feeding device arranged between a transfer device and a fusing device; and
FIG. 9 is a conceptual diagram illustrating an image forming apparatus having an air suction feeding device arranged at an outlet.
Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements, features, and structures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The matters defined in the description such as a detailed construction and elements are provided to assist in a comprehensive understanding of the embodiments of the invention. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
Referring to FIG. 3 and FIG. 4, an air suction feeding device according to an exemplary embodiment of the present invention includes a feed roller 110, air suction openings 120, and an air suction unit 130.
The feed roller 110 is configured with a shaft 111 and a plurality of rollers 113 arranged on the shaft 111. The shaft 111 is supported by a rotation support element (not shown), such as a bearing, arranged in an area where the feed roller 110 is located. Also, a power transmission element like a gear or a pulley is arranged on one end of the shaft 111, as in a general feed roller, to receive power from a motor, or the end of the shaft 111 is directly connected to the motor. The rollers 113 are arranged on the shaft 111 at regular intervals. Therefore, when the shaft 111 rotates the rollers 113 also rotate together. Each roller 113 may preferably be sized to have a diameter as large as possible in the space where the air suction feeding device 100 is arranged. If the size of the roller 113 is large, the linear velocity is reduced, the risk of printing medium slippage from the rollers is minimized. Thus, the size of the air suction openings 120 can be increased. The rollers 113 are preferably made of the same material used for the typical feed roller of an image forming apparatus, for example, EPDM rubber.
The air suction openings 120 are arranged between the rollers 113, in order to adhere one side of the printing medium to the surfaces of the rollers 113 through air suction. As can be seen in FIG. 3, the air suction openings 120 are arranged in the spaces 115 between the rollers 113 that are arranged on the shaft 111 at regular intervals. The location and the size of the air suction openings 120 are carefully determined so that the bottom side of the printing medium can closely contact the surfaces of the rollers 113, when the printing medium is entered into the feed roller 110 by the air suction through the air suction openings 120. Optionally, the air suction openings 120 may be arranged on only one side of the shaft 111 in spaces 115 between the rollers 113. In that case, however, the printing medium being attracted may be misaligned, or the suction force which attracts the printing medium may not be sufficiently strong. Therefore, it is preferable to install the air suction openings 120 on both sides of the shaft 111, that is, one at or near the front and one at or near the rear of the shaft 111 (in FIG. 4, the air suction openings are arranged on right and left sides of the shaft) in every space 115 between the rollers 113. In the embodiment shown in FIG. 3, a total of 8 air suction openings 120 are formed in the spaces 115 between five rollers 113.
The air suction unit 130 generates a suction force which sucks the air from the air suction openings 120. To this end, the air suction unit 130 includes a fan 131 and a suction duct 133. The suction duct 133 should be arranged in such a manner so that it can fluidly communicate the fan 131 with a plurality of the air suction openings 120, while causing no interference between the printing medium being transported. In the present embodiment, the suction duct 133 is arranged under the feed roller 110, and the fan 131 is attached to one end thereof. Here, the capacity of the fan 131 is preferably large enough to generate a suction force which attracts the printing medium from the air suction openings 120 and to adhere the printing medium onto the surfaces of the rollers 113 for transport.
It is also preferable to install a medium guide 140 behind the feed roller 110, in other words, in the feeding direction of the printing medium which is transported by the feed roller 110. The medium guide 140 separates the printing medium from the feed roller 110. More specifically, in order to prevent a wrap jam caused by the printing medium wrapping around the feed roller 110, the medium guide 140 is arranged in the vicinity of the feed roller 110, and parallel to the feed roller 1110. More preferably, a finger 141, which protrudes upward towards the air suction opening 120, may be formed in the space 115 between the rollers 113 as shown in FIG. 3 and FIG. 4. In this manner, the wrap jam problem can be resolved. The finger 141 is preferably molded in a shape that can facilitate the separation of the printing medium from the surfaces of the rollers 113. Also, it is important that the fingers 141 do not completely cover air suction openings 120 (please refer to FIG. 4).
The following will now explain the operation of the air suction feeding device according to the first exemplary embodiment of the present invention.
When a printing medium enters the feed roller 110, the fan 131 of the air suction unit 130 starts running. As a result, the air around the feed roller 110 is drawn into the air suction openings 120. Then, the front end of the printing medium is attracted towards the feed roller 110 and the bottom side thereof adheres onto the surfaces of the rollers 113. When the feed roller 110 rotates, the printing medium adheres onto the surface of the feed roller 110 and moves in the rotational direction of the feed roller 110. As the rotation of the feed roller 110 continues, the front end keeps moving forward via the medium guide 140. Once the front end of the printing medium goes over the medium guide 140, it may be readily separated from the surface of the feed roller 110 with the help of the finger 141 of the medium guide 140. Accordingly, the printing medium is not wound around the feed roller 110, and wrap jams can be avoided.
FIG. 5 is a perspective view of an air suction feeding device according to another exemplary embodiment of the present invention. Referring to FIG. 5, the air suction feeding device 200 according to this exemplary embodiment of the present invention includes a feed roller 210 which attracts a printing medium through air suction, an air suction unit 230 which generates a suction force, and a medium guide 240 to separate the printing medium from the feed roller 210.
The feed roller 210 is configured with a shaft 211 and a plurality of rollers 213 arranged on the shaft 211. The shaft 211 is supported by a rotation support element 202, such as a bearing, arranged in an area where the feed roller 210 is arranged. Also, a power transmission element (not shown), such as a gear or a pulley is arranged on one end of the shaft 211, as in a general feed roller, to receive power from a motor, or the end of the shaft 211 is directly connected to the motor. The rollers 213 are arranged on the shaft 211 at regular intervals. Therefore, when the shaft 211 rotates the rollers 213 also rotate together. Each roller 213 may preferably be sized to have a diameter as large as possible in the space where the air suction feeding device 200 is arranged. If the size of the roller 213 is large, the linear velocity is reduced, and the risk of printing medium slippage from the rollers can be minimized. The rollers 213 are preferably made of the same material used for the typical feed roller of an image forming apparatus, for example, EPDM rubber.
The air suction openings 220 are formed on the surfaces of the rollers 213 in order to attract one side of the printing medium to the surfaces of the rollers 213 through air suction. The air suction openings 220 are formed at regular intervals in the circumferential direction of each of the rollers 213. As shown in FIG. 6, the air suction openings 220 fluidly communicate with a duct 222 formed in axial direction of the shaft 211. The duct 222 communicates with an air hole 224 formed proximal to the center of the cross section on one end of the shaft 211 where neither the motor or the power transmission element is connected. Hence, the air around the air suction openings 220 is sucked into the air hole 224 through the duct 222. The size and the number of air suction openings 220 should be carefully selected to make sure that the suction force applied to the bottom side of the printing medium is strong enough to adhere the printing medium onto the surface of the feed roller 210. The suction force should also be strong enough to reduce the risk of printing medium slippage from the feed roller 210, while it does not cause any deformation of the printing medium.
The feed roller 210, having a plurality of air suction openings 220 formed thereon, can formed of any one of a number of suitable diverse shapes. FIG. 7 illustrates another possible exemplary embodiment of the feed roller. A feed roller 310 in this particular embodiment is distinguished by its shaft 311, which is integrally formed with a roller 313 instead of being separately fabricated. Other structural features, such as, an air hole 324 is formed on one end of the feed roller 310, and a duct 322 is arranged inside to communicate the air hole 324 with air suction openings 325 formed on the surface of the feed roller 310. These components are identical with the structure of the feed roller 210 according to the second embodiment of the present invention, therefore, a detailed description of the functions and constructions thereof are omitted for clarity and conciseness.
The air suction unit 230 generates a suction force which sucks air from the air suction openings 220. To this end, the air suction unit 230 includes a fan 231 and a suction duct 233. The suction duct 233 fluidly communicates the fan 231 and the air hole 224 of the shaft 211, and a rotation joint 235 is assembled to the joint portion thereof to enable the shaft 211 to rotate with respect to the fixed suction duct 233. Even though the suction duct 233 illustrated in FIG. 5 is in cylindrical shape, this is for illustrative purposes only, and other suitable shapes may be used. In effect, the suction duct 233 can be in diverse shapes, depending on where the shaft 211 and the fan 231 are arranged in an image forming apparatus. Also, the capacity of the fan 231 is carefully determined to generate a suction force that is strong enough to attract the printing medium from the air suction openings 220 and adhere it onto the surfaces of the rollers 213 for transport.
Then, the printing medium separates from the surface of the feed roller 210 with the help of a medium guide 240 arranged behind the feed roller 210, that is, in the feeding direction of the printing medium which is transported by the feed roller 210. More specifically, the printing medium, which has adhered onto the surface of the feed roller 210 through the air suction into the air suction openings 220, is now separated from the surface of the feed roller 210 with the help of the medium guide 240. Sometimes, the printing medium does not separate from the feed roller 210. This phenomenon is called a wrap jam. In order to prevent wrap jams, the medium guide 240 is arranged in the paper feeding direction behind the feed roller 210 and parallel to the feed roller 210. As shown in FIG. 5, the medium guide 240 includes fingers 241 opposite to the feed roller 210, which protrude to correspond to the intervals between the rollers 213.
When a printing medium, such as a sheet of paper, enters the feed roller 210 in the air suction feeding device 200, the fan 231 of the air suction unit 230 starts running. Once the fan 231 starts, the air around the feed roller 210 is drawn into the air suction openings 220. Then, the front end of the printing medium is attracted towards the surface of the feed roller 210, and the bottom side of the front end of the printing medium adheres onto the surface of the feed roller 210 through air suction into the air suction openings 220. When the feed roller 210 rotates, the printing medium adhered onto the surface of the feed roller 210 also moves. As the rotation of the feed roller 210 continues, the front end of the printing medium is placed on the medium guide 240 and the bottom side thereof separates from the feed roller 210 by the medium guide 240. Then, the printing medium on the medium guide 240 separates from the surface of the feed roller 210 and is transported forward. Here, the fingers 241 of the medium guide 240, disposed between the rollers 213, prevent the front end of the printing medium from entering between the medium guide 240 and the feed roller 210. In this manner, the wrap jam is effectively avoided and the printing medium can be transported easily without applying any kind of force to the top of the printing medium.
FIG. 8 and FIG. 9 illustrate electrophotographic image forming apparatuses, respectively, each having the above-described air suction feeding device of the exemplary embodiments of the present invention.
Referring to FIG. 8, an image forming apparatus 400 includes a paper feeding unit 410 which feeds printing media such as sheets of paper one after another, an image forming unit 420 which forms an image onto a printing medium provided from the paper feeding unit 410, and a feeding unit 430 to transport the printing medium to enable the image forming unit 420 to form an image thereon and release the printing medium bearing the image out of the image forming apparatus.
The image forming unit 420 includes photosensitive bodies 421 on which electrostatic latent images of printing data are formed and developed by developers, a transfer device 423 to transfer the images formed on the surfaces of the photosensitive bodies 421 onto a printing medium, and a fusing device 425 which fuses (or fixes) the transferred images onto the printing medium.
The feeding unit 430 includes a first feeding device 431 arranged between the paper feeding unit 410 and the transfer device 423 which feeds the printing medium picked from the paper feeding unit 410 to the transfer device 423, a second feeding device 433 arranged between the transfer device 423 and the fusing device 425 to feed the printing medium bearing the transferred image on the top surface to the fusing device 425, and a third feeding device 435 arranged between the fusing device 425 and an outlet 437 to release the printing medium with the fused image out of the image forming apparatus 400. The air suction feeding device is used in replacement of the second feeding device 433. Since the bottom side of the printing medium adheres onto a feeding roller 433 a for transport, the top side of the printing medium which bears a transferred image is not damaged and is accurately transported to the fusing device 425 via the transfer device 423.
Referring to FIG. 9, an image forming apparatus 400′ (which is another embodiment of electrophotographic image forming apparatus) has the same configuration with the image forming apparatus 400 in FIG. 8, except that the air suction feeding device is used in replacement of a third feeding device 435′ in a feeding unit 430.
Again in this particular embodiment, the bottom side of a printing medium bears a completely fused image adhered onto the feed roller 435 a through air suction, and this adhesion state is maintained until the printing medium is delivered outside through an outlet 437. Thus, wrap jam problems found in conventional feeding devices can be avoided.
While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An air suction feeding device comprising:

a feed roller comprised of a shaft and a plurality of rollers arranged on the shaft which feeds a printing medium;

a plurality of air suction openings arranged between the rollers to adhere one side of the printing medium onto the surfaces of the rollers; and

an air suction unit which sucks air from the air suction openings.

2. The air suction feeding device according to claim 1, wherein the air suction openings are arranged in spaces between the rollers, being disposed on at least two sides of the shaft.

3. The air suction feeding device according to claim 1 further comprises a medium guide arranged behind the feed roller to separate the printing medium from the surfaces of the rollers.

4. The air suction feeding device according to claim 3, wherein the medium guide comprises a plurality of fingers disposed between the rollers in such a manner so as to not cover the air suction openings.

5. An air suction feeding device comprising:

a feed roller which attracts a printing medium with air suction and feeds the printing medium;

an air suction unit which provides a suction force to the feed roller; and

a medium guide to separate the printing medium from the feed roller and guide the printing medium in a predetermined direction.

6. The air suction feeding device according to claim 5, wherein the feed roller is comprised of:

a plurality of air suction openings formed on a surface of the feed roller which attract one side of the printing medium to the surface of the feed roller through air suction;

an air hole formed on one end of the feed roller; and

a duct built inside the feed roller to fluidly communicate the air suction openings with the air hole.

7. The air suction feeding device according to claim 6, wherein the plurality of air suction openings are formed at regular intervals along the circumferential direction of the feed roller.

8. The air suction feeding device according to claim 7, wherein the plurality of air suction openings are formed along the axial direction of the feed roller.

9. The air suction feeding device according to claim 6, wherein the feed roller is comprised of:

a shaft; and

a plurality of rollers arranged at regular intervals on the shaft.

10. The air suction feeding device according to claim 9, wherein the air suction openings are formed along the circumferential direction of the rollers, respectively.

11. The air suction feeding device according to claim 9, wherein the duct is formed proximal to the center of the shaft.

12. The air suction feeding device according to claim 9, wherein the medium guide is comprised of a plurality of fingers disposed between the rollers.

13. An image forming apparatus comprising:

a paper feeding unit which provides a printing medium one after another;

an image forming unit which forms an image on the surface of the printing medium provided from the paper feeding unit;

a feeding unit to transport the printing medium to enable the image forming unit to form images thereon and release the printing medium which bears the image out of the image forming apparatus; and

an air suction feeding device arranged on the feeding unit which attracts one side of the printing medium onto the feed roller through air suction and transports the printing medium while maintaining the adhesion state of the printing medium onto the feed roller.

14. The image forming apparatus according to claim 13, wherein the air suction feeding device is comprised of:

a feed roller with a shaft and a plurality of rollers arranged on the shaft to transport the printing medium;

an air suction unit which sucks air from the air suction openings.

15. The image forming apparatus according to claim 14 further comprises a transfer device and a fusing device, and the air suction feeding device is arranged between the transfer device and the fusing device.

16. The image forming apparatus according to claim 14, wherein the air suction feeding device is arranged at an outlet to release the printing medium outside.