KR20040091412A - Paper feeding apparatus of image forming device having a paper pressing part - Google Patents

Abstract

PURPOSE: A paper feeding apparatus of an image formation device having a paper pressing part is provided to move a knockup plate between a pressing position, in which a paper makes contact with a pickup roller, and a release position, in which the paper is separated from the pickup roller, by using a carrier for moving a print head. CONSTITUTION: A paper feeding apparatus of an image formation device having a paper pressing part includes a knockup plate(132) supported at a paper receiving space of a paper feeding cassette(130) in order to move up and down with regard to one end of the paper feeding cassette(130) between an ascending position in which the paper makes contact with a pickup roller(140) and a descending position, in which the paper is spaced from the pickup roller(140). A knockup plate ascending part moves the knockup plate(132) to the ascending position and the descending position according to an action of a carrier(120).

Description

Paper feeding apparatus of an image forming apparatus having a paper pressing unit {Paper feeding apparatus of image forming device having a paper pressing part}

The present invention relates to a paper feeder used in an image forming apparatus such as a laser beam printer, a copier, an inkjet printer, a photo printer, and the like. More specifically, the paper can be picked up by a pickup roller when the paper is picked up. A paper press device of an image forming apparatus which presses a knock-up plate for loading paper against a pickup roller and spaces the knock-up plate away from the pickup roller so that the paper can be easily conveyed during paper transfer.

Generally, image forming apparatuses such as laser beam printers, copiers, ink jet printers, and the like, particularly ink jet printers, have print heads that eject ink to form an image on paper P, as shown in Figs. The ink cartridge 1, the carrier 2 for reciprocating the ink cartridge 1 in the left and right directions, and the paper feeders 3, 4, 5, 6, 7, which feed the paper P into the printer. 8).

The paper feed units 3, 4, 5, 6, 7, and 8 have a paper feed cassette 3 for loading paper P, a pickup roller 4 for picking up paper P, and a paper sensor for detecting paper. (Not shown), and the transfer roller 5 for aligning and transferring the leading end of the paper P, the leading end of the paper P is aligned for a predetermined time in the transfer roller 5, and then The resist sensor 6 which controls to drive, the guide 7 for conveying the paper P, and the discharge roller 8 which discharges the paper P are comprised.

The paper feed cassette 3 is provided with a knock-up plate 13 supported by the compression spring 14 to press the paper against the pickup roller 4 at a constant pressure.

Looking at the operation of such an inkjet printer, according to a printing command from a computer, the pickup roller 4 picks up sheets of paper P from the paper cassette 3 one by one and feeds them along the guide 7 toward the feed roller 5 side. Let's go.

At this time, the resist sensor 6 installed in front of the conveying roller 5 is operated by the paper P, and accordingly, the control unit (not shown) moves from the resist sensor 6 to the inlet of the conveying roller 5. The distance is calculated in time to drive the pickup roller 4 until the leading end of the paper P is aligned, generating curl at the nip between the transfer roller 5 and the backup roller 10.

After the leading end of the paper P is aligned, the control unit stops the pickup roller 4 and simultaneously drives the transfer roller 5 to move the paper P below the nozzle 1a of the print head of the ink cartridge 1. To the printing area.

When the paper P is conveyed to the printing area, the carrier 2 ejects the ink while reciprocating the ink cartridge 1 in the left and right directions to proceed with printing.

In this way, when printing is completed, the discharge roller 8 discharges the paper P, and completes one cycle of printing.

However, such a conventional inkjet printing presses the paper P against the pick-up roller 4 at a constant pressure not only when the knock-up plate 13 of the paper feeder 3 of the paper feeder is picked up but also when the paper is transported. Since the rear end of the paper P is separated between the pickup roller 4 and the knock-up plate 13 by the feed roller 5 after the paper P is picked up, the paper feed rate is reduced due to the instantaneous reduction in resistance. This is instantaneously changed, and there is a problem that an image defect such as a white line occurs in an image printed on a sheet.

In addition, since the pick-up roller 4 is always in contact with the printing surface of the paper P at a constant pressing force, there is a problem that the marks of the pickup roller 4 are generated on the printing surface of the paper P, and the image quality is deteriorated. Such marks on the pick-up roller 4 cause a fatal defect in the image when the paper is photo paper.

The present invention has been made to solve the above problems, an object of the present invention is a knock-up plate to the pressing position for contacting the paper to the pickup roller by the carrier for transporting the print head and the release position to separate the paper from the pickup roller. There is provided a paper feed apparatus of an image forming apparatus having a paper pressing portion for allowing the to be moved.

Another object of the present invention is to drive the carrier drive motor and the pickup roller when picking up the paper by locking the knock-up plate at a pressing position for contacting the paper against the pickup roller even if the carrier driving motor for driving the carrier is not driven continuously. It is not necessary to drive the feed motor at the same time, thereby preventing the overload caused by the continuous driving of the carrier drive motor, reducing the power consumption, and at the same time the paper of the image forming apparatus having a paper pressing unit that can lower the output voltage required for the machine. To provide a supply.

1 is a partial perspective view of a conventional inkjet printer.

FIG. 2 is a cross-sectional view of the ink jet printer shown in FIG. 1. FIG.

3 is a perspective view of a paper feeding device of an inkjet printer having a paper pressing portion according to the present invention.

4A, 4B, and 4C are side views illustrating the operation of the locking portion of the paper feed apparatus shown in Fig. 3 shown in the line I-I direction of Fig. 3;

5A, 5B, 6A, 6B, 7A, and 7B are plan and side views illustrating the paper pick-up and transfer operations of the paper feed apparatus of Fig. 3;

* Description of the symbols for the main parts of the drawings *

1: ink cartridge 2, 120: carrier

3, 130: paper cassette 5, 145: feed roller

6: sensor 7, guide

8: delivery roller 20: main body

100: paper feed unit 132: knock-up plate

140: pickup roller 157: pickup roller drive gear

162, 168, 182: return member 163: operating lever

164: rotational motion converting member 165: slider

167: crank 169, 195, 238: tension member

180: linear motion conversion member 190: paper separator

191: paper separation member 193: paper separation roller

220: locking portion 223: locking member

225: link member 227, 229: link

231: working protrusion 232: locking recess

239, 240: tension spring

In order to achieve the above object, the present invention is directed to a frame constituting the main body, a paper feed cassette or tray provided with respect to the frame and having a paper receiving space for loading paper, and a pickup roller and a pickup roller for picking up the paper loaded in the paper cassette. A paper feeding device of an image forming apparatus, comprising: a conveying unit having a conveying roller for conveying the paper picked up by a carrier; and a carrier for reciprocating the print head so as to print the paper conveyed through the conveying unit. A knock-up plate supported in the paper receiving space for lifting up and down about at least one end of the paper cassette between the rising position to be contacted and the lowering position to be spaced apart, and the knock-up plate lifting to move the knock-up plate to the rising position and the lowering position according to the operation of the carrier. The upper and lower knock-up plates It provides a paper feeder for an image forming apparatus having a paper pressing plate comprising the locking unit for locking the lifting unit to nokeop maintained at a single location.

The knock-up plate lifting unit has a rotational movement converting member installed in the frame so as to change the linear movement of the carrier, which occurs when the carrier moves in one direction, to the rotational movement, and the linear movement of the rotational movement converting member perpendicular to the moving direction of the carrier. It is composed of a linear motion converting member for transferring to the knock-up plate.

The rotary motion converting member has a slider and a slider formed at least one sliding bracket which is horizontally disposed in the movement path of the carrier at one end thereof so as to linearly move by the carrier, and at least one sliding bracket supported by the carrier so as to be movable in the frame. A crank having one end arranged to rotate by the end and the other end twisted at an angle with respect to one end to rotate to an up and down position when one end is rotated, when the slider moves in one direction by the carrier And a crank tensioning member for tensioning one end to rotate in one direction, and a slider returning member for returning the slider to its original position so that the other end of the slider rotates one end of the crank in the other direction when the carrier moves in the other direction. The crank tension member is composed of a first tension spring disposed between one end of the crank and the slider, the slider return member is the other end of the slider in the other direction when the carrier moves in the other direction to return to the original position It is preferably composed of a first compression spring disposed between the sliding bracket and the support shaft for supporting the sliding bracket to rotate.

The linear motion conversion member has a first end surface protruding to contact the other end of the crank so that one end is hinged to the frame and the other end is lifted together when the other end of the crank rotates between the raised and lowered positions. And a second end face formed opposite the knock up plate located opposite the first end face to raise the knock up plate when the first end face rises by rotation to the raised position of the other end of the crank. And a driver return member for lowering the knockup plate driver when the other end of the crank rotates to the lowered position. The driver return member is comprised of a second tension spring disposed between the other end of the crank and the second end surface of the other end of the knockup plate driver.

The locking part is provided with a locking member installed on the frame, the slider moves together with the slider when the carrier moves in one direction to move to a latching position engaged with the locking member and a release position released from the locking member by the carrier when the carrier moves in the other direction. A link member installed relative to the tension member, and a tension member for tensioning the link member to the locked position when the slider moves in one direction by the carrier.

The link member is supported by a first link having one end rotatably supported by the slider, and rotatably supported by the other end of the first link, and pressed down by the carrier when the carrier moves in the other direction. And a second link having one end having an actuating protrusion disposed in the conveying path and the other end having a catching recess to engage the engaging member when the slider moves in one direction by the carrier.

The tension member is composed of a third tension spring disposed between the slider and the other end of the first link, and a fourth tension spring disposed between the other end of the second link and one end of the first link.

Hereinafter, a preferred embodiment of a paper feed apparatus of an image forming apparatus having a paper pressing portion according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to Fig. 3, a paper feed apparatus 100 having a paper pressing portion of the present invention is illustrated.

An image forming apparatus to which the paper supply apparatus 100 of the present invention is applied, for example, an inkjet printer, has an ink cartridge (not shown) and an ink cartridge having a print head (not shown) having a nozzle (not shown). And a printing apparatus unit having a carrier 120 for printing by reciprocating the ink cartridge left and right by a separate carrier driving motor (not shown).

The configuration of the printing unit is that the operating projection 120a is formed on the lower surface of the printer 120 so as to be engaged with the operating protrusion 163a of the operating lever 163 to move the operating lever 163 when the carrier 120 is moved left and right. Except for the points, since it is the same as the conventional inkjet printer shown in Fig. 1, detailed description is omitted.

The actuating lever 163, together with the actuating lever return member 162, includes a stationary gear (155) formed in the hinge bracket 135b of the rotary gear member 155 provided to be movable on the pickup roller shaft 143 of the pickup roller 140. 153), the paper cassette opening and closing device for automatically rotating the paper feed cassette 130 loaded with the paper (P; FIGS. 7A and 7B) to a vertical position as a storage position and a horizontal position where it is ready for use. The operation unit 160 of the unit 110 is configured. The construction and operation of the operation lever 163 and the paper cassette opening and closing unit 110 are disclosed in detail in Korean Patent Application No. 2003-3516 filed on January 18, 2003 by the present applicant.

The paper feed apparatus 100 of the present invention includes a frame (not shown) constituting a paper feed path; A paper feed tray or cassette 130 rotatably installed with respect to the frame and having a paper receiving space 131 for loading paper P; Transfer unit portions 140 and 145 for picking up and transporting the paper P loaded in the paper feed cassette 130; And paper pressing device portions 132, 164, 180, and 220 which press the paper P against the pickup roller 140 so that the paper P may be picked up by the pickup roller 140 when the paper is picked up.

The conveying units 140 and 145 include a pickup roller 140 for picking up the paper P loaded in the paper cassette 130, and a feed roller 145 for transporting the paper picked up by the pickup roller 140 (Fig. 7A). And (b) a feeding motor (not shown) connected to the pickup roller 140 and the transfer roller 145 via a gear train to drive the pickup roller 140 and the transfer roller 145.

The paper pressing device portions 132, 164, 180, and 220 are provided with respect to one end of the paper feed cassette 130 between a rising position (FIG. 6B) for contacting the paper with respect to the pickup roller 140 and a lowering position (FIG. 5B) for separating the paper. In accordance with the movement of the knock-up plate 132 supported by the paper receiving space 131, the operating lever 163 operated by the carrier 120 to move the knock-up plate 132 to the up position and the down position The knockup plate lifting units 164 and 180 and the locking unit 220 for locking the knockup plate lifting units 164 and 180 to maintain the knockup plate 132 in at least one of a rising position and a lowering position.

The knock up plate elevating portions 164, 180 are linear movements of the actuating lever 163 operated by the carrier 120 when the carrier 120 moves in one direction, for example, to the left of FIG. 3 (upper in FIG. 6A). The knock-up plate 132 is lowered by changing the rotational motion of the rotational motion conversion member 164 and the rotational motion conversion member 164 installed in the frame to a linear motion perpendicular to the moving direction of the carrier 120 to change the rotational motion to the rotational motion. It is composed of a linear motion conversion member 180 for transmitting to the knock-up plate 132 to rise to a position or an elevated position.

The rotary motion converting member 164 forms an interlocking protrusion 165a disposed horizontally in the movement path of the operating lever 163 at one end so as to linearly move by the operating lever 163 operated by the carrier 120. In the lower part, the slider 165 and the actuating lever 163, which form the first and second sliding brackets 166a and 166b, which are supported to be movable to the support 121 of the frame, are returned to their original positions by the actuating lever return member 162. One end 167a and one end 167a arranged to rotate by the other end 165b of the slider 165 returned together when returning to the up position (FIG. 6B) and the down position (FIG. 5B) Crank 167 having the other end 167b twisted at an angle with respect to one end 167a so as to rotate in one direction, the actuating lever 163 is driven by the carrier 120 in one direction, for example the left side of FIG. To one end 167a of the crank 167 when the slider 165 moves to the left. Crank tensioning member 169 which is tensioned to rotate in a counterclockwise direction, for example counterclockwise in FIG. 3, and a carrier 120 which is moved to the other direction, ie to the right in FIG. As the force of 120 is removed, the other end 165b of the slider 165 is cranked when the actuating lever 163 is moved to the other direction by the actuating lever return member 162, that is, to the right in FIG. The slider return member 168 moves the slider 165 to the right to return one end 167a of the other side 167a to the other direction, that is, clockwise in FIG. 3.

The crank tensioning member 169 has a first spring fixing hook 167a 'formed at one end 167a of the crank 167 and a second spring formed at the first sliding bracket 166a below the slider 165. It is composed of a first tension spring disposed between the fixed hook (166a '), the slider return member 168 is a spring support (formed on the support shaft 174 for supporting the first and second sliding brackets (166a, 166b) ( It is preferably composed of a first compression spring disposed on the support shaft 174 between 174a and the second sliding bracket 166b.

In the above-described embodiment, the slider 165 of the rotary motion converting member 164 has been described as being operated by the carrier 120 via the actuating lever 163, but the present invention is not limited thereto, and the slider ( 146 may be configured to be operated directly by carrier 120 without using actuation lever 163.

One end 181a of the linear motion conversion member 180 is hingedly supported by the support 221 of the frame by the hinge shaft 181a ', and the other end 181b is the other end 167b of the crank 167. The first end face 181b 'and the first end protruding to contact the other end 167b of the crank 167 so that when the machine rotates between the raised position (FIG. 6B) and the lowered position (FIG. 5B), it can move up and down together. A knockup plate located opposite the first end face 181b 'to raise the knockup plate 132 when the face 181b' rises by the rotation of the other end 167b of the crank 167 to the raised position. The knock up plate driver 181 having the second end surface 181 b ″ formed to face 132, and the knock up plate driver 181 when the other end 167 b of the crank 167 rotates to the lowered position. The driver return member 182 which lowers and returns is provided.

The driver return member 182 includes a third spring fixing hook (not shown) of the other end 167b of the crank 167 and a second end surface 181b ″ of the other end 181b of the knockup plate driver 181. It consists of a second tension spring disposed between the fourth spring fixed hook (not shown) formed in the.

The locking part 220 moves the locking member 223 and the carrier 120 installed in the support part 221 of the frame 221 in one direction, for example, the left side of FIG. 3 (the arrow A direction in FIG. 4A). When the moving lever 163 moves together with the slider 165 and engages with the locking member 223, the locking position (FIG. 4B) and the carrier 120 are in the other direction, that is, the right side of FIG. 3 (the arrow of FIG. 4C). The link member 225 provided with respect to the slider 165 to move to the release position (FIG. 4A) which is released from the locking member 223 by the carrier 120 when moving in the It includes a tension member 238 that is tensioned so that the link member 225 can be positioned in the locking position when moving to the left side of FIG. 3 (in the direction of arrow A of FIG. 4A) by 120.

The locking member 223 is formed of a protrusion formed in the support part 221 of the frame to be engaged or released with the locking recess 232 formed in the second link 229 of the link member 225 described later.

The link member 225 has a straight first link 227 having one end supported to rotate on the first pivot shaft 234 of the slider 165; And the other end of the first link 227 is rotatably supported on the second pivot shaft 230, and the carrier 120 is moved to the right side of FIG. 3 (arrow B in FIG. 4C) at the locking position (FIG. 4C). Direction of the slider 165 and the one end 229a having the semicircular actuating protrusion 231 disposed in the conveying path of the carrier 120 so as to be pressed down by the actuating protrusion 120a of the carrier 120 when moving in the When the one end 165a is pushed to the left side of FIG. 3 (in the direction of arrow A of FIG. 4A) by the actuating protrusion 120a of the carrier 120, the catch recess 232 engaged with the catching member 223 is provided. It is composed of a second link (229) of the L-shape having the other end 229b having.

The tension member 238 is a third tension spring 239 disposed between the fifth spring fixing hook 235 formed at the slider 165 and the sixth spring fixing hook 236 formed at the other end of the first link 227. And the seventh spring fixing hook 233 formed at the end of the other end 229b of the second link 229 and the eighth spring fixing hook 237 formed at one end of the first link 227. Fourth tension spring 240.

The paper supply apparatus 100 of the present invention further includes a paper separator 190 for separating and supplying sheets of paper at the time of picking up the paper P.

The paper separator 190 is a knock-up plate when the knock-up plate driver 180 moves up and down to lift the paper separation roller 193 and the knock-up plate 130 fixed to the shaft 194 rotatably supported by the frame. It consists of a paper separating member 191 disposed in contact with or separated from the paper separating roller 193 in conjunction with the driver 180.

The paper separating member 191 has one end 192a hingedly fixed to the support 121 of the frame by a hinge shaft 192a ', and the other end 192b is in contact with the paper separating roller 193. The friction pad member 192 forming the 196, and the contact pad 196 of the friction pad member 192 to come into contact with the paper separation roller 193 when the knock-up plate driver 180 is raised. 192 is composed of a friction pad tensioning member 195 that tensions the paper separation roller 193 toward the paper separation roller 193.

The friction pad tension member 195 may include a ninth spring fixing hook 191c 'and a knock-up plate driver 180 formed at a spring hook portion 192c formed at both ends thereof protruding from the other end 192b of the friction pad member 192. It is preferable that it is composed of fifth tension springs respectively fixed to the tenth spring fixing hooks 181c formed on the second end surface 181b ″ of the other end 181b.

The paper supply apparatus 100 of the inkjet printer having the paper pressing unit configured as described above will be described in detail with reference to FIGS. 3 to 7B as follows.

First, in order to pick up the paper loaded in the paper feed cassette 130, as shown in FIG. 5A, the actuating projection 120a of the carrier 120 is located below the actuating protrusion 163a of the actuating lever 163 (FIG. In the state located at the right side of 3, the pickup roller drive gear 157 is rotated clockwise to raise the operation lever 163 to the raised position by the feed motor, as shown in Fig. 6B.

After the actuating lever 63 is raised to the raised position, as shown in Fig. 6A, the carrier 120 is moved upward (Fig. 3 left) of Fig. 6A by the carrier drive motor, and as a result, the actuation lever 163 is also moved upward by an actuating protrusion 163a that engages actuating protrusion 120a of carrier 120.

As the actuation lever 163 moves upwards, one end 165a of the slider 165 installed to interlock with the actuation lever 163 is pushed upward (left side in FIG. 3), thus the slider 165 Moves upward along the support shaft 174 through the first and second sliding brackets 166a and 166b against the elastic force of the slider return member 168.

As the slider 165 moves upwards (left of FIG. 3), as shown in FIG. 4A, the top surface of the second link 229 of the locking portion 222 may have the third and fourth tension springs 239. , 240, while sliding in friction with the locking member 223 moves in the direction of the arrow (A).

In this case, as shown in FIG. 3, the crank tensioning member 169 disposed between the first sliding bracket 166a and the one end 167a of the crank 167 may have one end portion of the crank 167. 167a is pulled upward to the left side of FIG. 3, that is, upward of FIG. 6A, and as a result, the other end 167b twisted at an angle with one end 167a is rotated to the raised position.

As the other end 167b of the crank 167 rotates to the raised position, the knock-up plate driver 181 contacts the first end surface 181b of the other end 181b in contact with the other end 167b of the crank 167. Upped by ').

Accordingly, as shown in FIG. 6B, the knock-up plate 132 that is in contact with the second end surface 181b ″ of the other end 181b of the knock-up plate driver 181 has a pick-up roller Lifted up to contact 140.

At this time, the friction pad member 192 of the paper separating member 191 is attached to the friction pad tension member 195 provided between the spring hook portion 192c and the second end surface 181b ″ of the knock-up plate driver 181. As a result, it is raised together with the knockup plate driver 181, and the contact pad 196 comes into contact with the paper separation roller 193 at a predetermined pressure.

As such, when the contact pad 196 contacts the paper separation roller 193 at a constant pressure, the second and second links 229 of the locking portion 222 are formed by the third and fourth tension springs 239 and 240. As shown in FIG. 4B, the locking member 223 sliding and friction with the top surface is locked to the locking recess 232, and thus the slider 165 is connected to the second link () of the link member 225 located at the locking position. 229) is fixed so as not to move.

Therefore, the carrier driving motor for driving the carrier 120 can be stopped without the need for continuous driving, thereby preventing overload and continuous power consumption due to the continuous driving of the carrier driving motor.

In addition, since the paper feed motor for driving the carrier driving motor and the pickup roller 140 does not need to be driven at the same time in the next step of paper pickup, the output voltage of the printer can be reduced.

Thereafter, the pickup roller drive gear 157 is rotated in the counterclockwise direction (clockwise in FIGS. 3 and 6B) to pick up the paper P, as shown in FIG. 140 picks up the paper P and transfers the sheet P toward the feed roller 145 sheet by sheet through the nip between the paper separating roller 193 and the contact pad 196 of the paper separating member 191.

At this time, the actuating lever 163 is provided with a rubber ring (not shown) installed to elastically contact the actuating lever 163 on the pick-up roller shaft 143 even when the pick-up roller drive gear 157 rotates in the counterclockwise direction. By idling without further rotation.

Then, when the paper P operates the paper detection sensor (not shown) in front of the feed roller 145, the control unit calculates the distance from the paper sensor to the entrance of the feed roller 145 in time to obtain the paper. The pick-up roller 140 is driven until the tip portion of (P) is aligned while generating curl in the nip between the transfer roller 145 and the backup roller 146.

In this manner, after the paper P is picked up by the pickup roller 140, the carrier 120 has the actuating protrusion 120a to be released from the actuating protrusion 163 of the actuating lever 163. It moves downward (right side of FIG. 3, arrow B direction of FIG. 4C), and as a result, the actuating lever 163 is moved to the right side by the elastic force of the actuating lever return member 162, and is returned to its original position.

Thereafter, when the carrier 120 continues to move downward (right side in FIG. 3, in the direction of an arrow B in FIG. 4C), as shown in FIG. 4C, the actuating protrusion 120a of the carrier 120 is formed in a second manner. The actuating protrusion 231 of the link 229 is pushed down so that the second link 229 rotates down about the first pivot shaft 234 so that the locking member 223 is connected to the second link 229. Is released from the locking recess 232.

At this time, the slider return disposed on the support shaft 174 between the spring support portion 174a formed on the support shaft 174 supporting the first and second sliding brackets 166a and 166b and the second sliding bracket 166b. Since the first compression spring of the member 168 pushes the slider 165 downward (right in FIG. 3, in the direction of the arrow B in FIG. 4C), the locking member 223 has an upper surface of the second link 229. It moves along and is located in the position shown in FIG. 4A, and the slider 165 is moved downward by the slider return member 168, and is returned.

As such, when the slider 165 returns to the lower side (right side in FIG. 3), the other end 165b of the slider 165 is pushed to rotate one end 167a of the crank 167 in a clockwise direction, Accordingly, the other end 167b of the crank 167 is rotated to the lowered position.

As the other end 167b of the crank 167 rotates to the lowered position, the knock-up plate driver 181 contacts the first end surface 181b of the other end 181b in contact with the other end 167b of the crank 167. Descended by ').

Accordingly, the knock-up plate 132 which is in contact with the second end surface 181b 'of the other end 181b of the knock-up plate driver 181 is lowered so that the paper loaded thereon does not contact the pickup roller 140. To descend.

At this time, the friction pad member 192 of the paper separation member 191 is lowered due to the disappearance of the tension of the friction pad tension member 195 with the lowering of the knock-up plate driver 181, and the contact pad 196 is paper It is separated from the separation roller 193.

Thereafter, the feed motor rotates the pickup roller drive gear 157 in the counterclockwise direction (clockwise in FIGS. 7A and 7B) to drive the feed roller 145.

As a result, since the paper P is spaced apart from the pickup roller 145 by the knock-up plate 132 located in the lowered position, the pickup roller 145 is idle, and the paper P is fed to the feed roller 145. Is transferred to the print area below the nozzle of the print head of the ink cartridge. At this time, the operation lever 163 is in the lowered position (FIG. 5B) which does not collide with the carrier 120 according to the counterclockwise rotation of the pickup roller drive gear 157 (clockwise in FIGS. 7A and 7B). After moving to, no more rotation is idle.

When the paper P arrives at the print area under the print head, the carrier 120 reciprocates left and right by the carrier driving motor while spraying ink through the nozzle of the print head of the ink cartridge to perform printing.

After printing is completed, the paper is discharged through a discharge roller (not shown).

As described in detail above, the paper feed apparatus of the image forming apparatus having the paper pressurizing portion of the present invention has a press position for contacting the paper with respect to the pickup roller by a carrier for conveying the print head and a release position for separating the paper from the pickup roller. You can move the knockup plate with

In addition, the paper feeder of the image forming apparatus having the paper pressurizing portion of the present invention makes it possible to lock the knock-up plate at a pressurized position for pressing the paper against the pickup roller even if the carrier driving motor for driving the carrier is not driven continuously. It is not necessary to simultaneously drive the carrier drive motor and the feed motor for driving the pickup roller during pickup, thereby preventing overload due to continuous driving of the carrier drive motor, reducing power consumption and lowering the output voltage required for the device. Can be.

In the above, certain preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiments, and any person having ordinary skill in the art to which the present invention pertains without departing from the spirit and spirit of the present invention as claimed in the claims may have various modifications and Modifications may be made.

Claims (7)

In the paper feed apparatus of the image forming apparatus, A knock-up plate supported in the paper receiving space of the paper feed cassette so that the paper can be raised and lowered at least about one end of the paper feed cassette between an ascending and spaced apart position where the paper is brought into contact with the pickup roller; A knockup plate elevating unit which moves the knockup plate to an up position and a down position according to an operation of a carrier; And And a locking portion for locking the knockup plate lifting portion so as to maintain the knockup plate at at least one of a rising position and a lowering position. According to claim 1, The knock-up plate lifting unit, A rotational movement converting member installed in the frame so as to change the linear movement of the carrier generated by the movement of the carrier in at least one direction to the rotational movement; And And a linear motion converting member for converting the rotational motion of the rotational motion converting member into a linear motion perpendicular to the moving direction of the carrier and transmitting the linear motion converting member to the knockup plate. The method of claim 2, wherein the rotary motion conversion member, A slider formed at one end thereof with an interlocking protrusion arranged horizontally in the movement path of the carrier so as to be linearly moved by the carrier, and at least one sliding bracket supported at the lower part so as to be movable in the frame; A crank having one end arranged to rotate by the other end of the slider and the other end twisted at an angle with respect to the one end such that the one end rotates in a raised position and a lowered position when the one end rotates; A crank tension member that tensions the one end of the crank to rotate in one direction when the slider moves in one direction by the carrier; And And a slider return member for returning the slider to its original position so that the other end of the slider rotates the one end of the crank in the other direction when the carrier moves in the other direction. Form feeder. The method of claim 3, wherein the linear motion conversion member, One end is hinged to the frame and the other end is protruded so as to contact the other end of the crank so that the other end of the crank can move up and down as it rotates between an up position and a down position; A second end face formed opposite the knock up plate located opposite the first end face to raise the knock up plate when the first end face rises by rotation of the other end of the crank to the raised position; A knock-up plate driver; And And a driver return member for lowering the knockup plate driver when the other end of the crank rotates to the lowered position. The method of claim 2, wherein the locking unit, A locking member installed on the frame; When the carrier moves in one direction, it moves with the slider of the rotational motion converting member to engage the engaging position with the locking member and to the release position released from the locking member by the carrier when the carrier moves in the other direction. A link member installed with respect to the slider; And And a tensioning member for tensioning the link member to the latched position when the slider is moved in one direction by a carrier. The method of claim 5, wherein the link member, A first link having one end rotatably supported by the slider; And One end of the slider and a slider having an actuating protrusion disposed in a transport path of the carrier so as to be pivotally supported at the other end of the first link and to be pressed down by the carrier when the carrier moves in the other direction; And a second link having the other end having a locking recess to engage with the locking member when moved in one direction by a carrier. The method of claim 6, wherein the tension member, A first tension spring disposed between the slider and the other end of the first link; And And a second tension spring disposed between said other end of said second link and said one end of said first link.