JP2015221503A - Conveying device and inkjet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveying device and an inkjet recording device that can effectively give to a conveying belt negative pressure with which a recorded medium is suctioned into the conveying belt.SOLUTION: A conveying device 300 conveys a recorded medium P. The conveying device comprises a conveying belt 355, a suction roller 352 and a suction portion 360. The conveying belt supports the recorded medium. The suction roller pressurizes the recorded medium on the conveying belt. The suction portion suctions the recorded medium through the conveying belt. The suction portion includes a guide member 362. The guide member supports the recorded medium through the conveying belt. The guide member has a penetration hole 365a that gives negative pressure to the recorded medium. The penetration hole is formed in a region other than a region opposing to the suction roller of the guide member.

Description

  The present invention relates to a transport apparatus and an ink jet recording apparatus for transporting a recording medium.

  In recent years, a line head type has been adopted in an ink jet recording apparatus in order to improve a recording speed onto a recording medium (for example, a copy sheet). In a line head type inkjet recording apparatus, a plurality of line heads are arranged and fixed in the conveyance direction of a recording medium, and the recording medium is placed on a conveyance belt and conveyed to a position facing each of the plurality of line heads. . Then, ink is ejected from the nozzles of the plurality of line heads to form an image on the recording medium.

  When transporting a plurality of recording media continuously to a position opposite to the inkjet head at high speed, it is effective to adsorb the recording media to the transport belt in order to suppress displacement of the recording media with respect to the transport belt. It is. The ink jet recording apparatus disclosed in Patent Document 1 has a structure for adsorbing a recording medium onto a conveyance belt.

  In this ink jet recording apparatus, the conveyance belt has a plurality of through holes, and the guide member arranged to face the back surface of the conveyance belt has a plurality of grooves and a plurality of through holes. Then, negative pressure generating means arranged opposite to the back surface of the guide member adsorbs the recording medium onto the conveyance belt through the groove and the through hole of the guide member and the through hole of the conveyance belt.

  In addition, the ink jet recording apparatus disclosed in Patent Document 1 includes a suction roller that presses a recording medium against a conveyance belt. In this ink jet recording apparatus, the recording medium can be more reliably adsorbed onto the conveying belt than the ink jet recording apparatus that adsorbs the recording medium to the conveying belt only by negative pressure.

JP 2004-90490 A

  However, the inkjet recording apparatus disclosed in Patent Document 1 has the following problems. That is, since the suction roller presses the recording medium against the transport belt, the recording medium is unlikely to lift from the transport belt in a region of the transport belt that faces the suction roller. In the ink jet recording apparatus disclosed in Patent Document 1, since the through hole formed in the guide member faces the suction roller, a negative pressure is applied to a region of the transport belt facing the suction roller. In order to effectively suppress the lifting of the recording medium from the conveying belt, it is preferable to apply a negative pressure to the portion of the conveying belt where the recording medium is easily lifted. Since the negative pressure applied to the recording medium decreases as the number of through holes increases, it is preferable to provide the through holes in a region with high suction efficiency without increasing the number of through holes.

  The present invention has been made in view of the above problems, and provides a transport apparatus and an ink jet recording apparatus that can effectively apply a negative pressure for sucking a recording medium to the transport belt to the transport belt. It is aimed.

  According to the first aspect of the present invention, the transport device transports a recording medium. The transport device includes a transport belt, a pressing member, and a suction unit. The conveyance belt supports the recording medium. The pressing member presses the recording medium onto the transport belt. The suction unit sucks the recording medium through the transport belt. The suction part includes a guide member. The guide member supports the recording medium via the transport belt. The guide member has a through hole that applies a negative pressure to the recording medium. The through hole is formed in a region of the guide member other than the region facing the pressing member.

  According to a second aspect of the present invention, an image forming apparatus includes the transport device according to the first aspect of the present invention and a recording head. The recording head performs recording on the recording medium.

  According to the present invention, the negative pressure for sucking the recording medium to the transport belt can be effectively applied to the transport belt.

1 is a schematic diagram illustrating a schematic configuration of an ink jet recording apparatus including a transport device according to an embodiment of the present invention. It is a top view of the guide member of the conveying apparatus which concerns on embodiment of this invention. It is sectional drawing of the guide member of the conveying apparatus which concerns on embodiment of this invention. It is a top view of the guide member of the conventional conveying apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an ink jet recording apparatus 1. The ink jet recording apparatus 1 includes a transport device 300. The conveyance device 300 includes a conveyance belt 355, a suction roller 352 as a pressing member, and a suction unit 360. The conveyor belt 355 supports the recording medium P. The suction roller 352 presses the recording medium P onto the transport belt 355. The suction unit 360 sucks the recording medium P via the transport belt 355. The suction part 360 includes a guide member 362. The guide member 362 supports the recording medium P via the conveyance belt 355.

  FIG. 2 is a plan view of the guide member 362, and FIG. 3 is a cross-sectional view of the guide member 362. The guide member 362 has a plurality of through holes 365a. The plurality of through holes 365a apply a negative pressure to the recording medium P. The plurality of through holes 365a are formed in a region of the guide member 362 other than the region facing the suction roller 352. Accordingly, a negative pressure is not applied to a region of the transport belt 355 that faces the suction roller 352, and a negative pressure is applied to a region other than the region. As a result, a negative pressure for sucking the recording medium P onto the transport belt 355 can be effectively applied to the transport belt 355.

  Details of the configuration of the inkjet recording apparatus 1 will be described with reference to FIG. The ink jet recording apparatus 1 includes an apparatus housing 10, a paper feed unit 20 disposed below the inside of the device housing 10, an ink jet recording type image forming unit 30, and a paper discharge unit 40.

  The paper feed unit 20 includes a paper feed cassette 200. The paper feed cassette 200 is detachably attached to the apparatus housing 10. In the paper feed cassette 200, a plurality of recording media P are stored in a stacked state. The recording medium P is, for example, paper such as plain paper, recycled paper, thin paper, or thick paper.

  The image forming unit 30 includes a conveyance device 300 and a recording head 390. The transport apparatus 300 includes a first paper transport unit 310 and a second paper transport unit 350 disposed to face the recording head 390. The second paper transport unit 350 is disposed between the first paper transport unit 310 and the paper discharge unit 40. Note that the image forming unit 30 may include a drying device (not shown). The drying device dries the ink droplets ejected on the recording medium P.

  The first paper transport unit 310 includes a paper transport path 311, a paper feed roller 312, a first transport roller pair 313, a second transport roller pair 314, a registration roller pair 315, and a guide plate 316. The paper feed roller 312 is provided above one end side of the paper feed cassette 200. The first transport roller pair 313 is provided on the entrance side of the paper transport path 311. The second transport roller pair 314 is provided in the middle of the paper transport path 311. The registration roller pair 315 is provided on the exit side of the paper transport path 311. The guide plate 316 is provided between the paper feed roller 312 and the first transport roller pair 313.

  In FIG. 1, the X axis is parallel to a direction orthogonal to the conveyance direction D of the recording medium P. The Y axis is parallel to the conveyance direction D of the recording medium P on the guide member 362. The Z axis is parallel to the direction orthogonal to the upper surface of the guide member 362. In the first embodiment, the Z axis is the vertical direction, and the X axis, the Y axis, and the Z axis are orthogonal to each other.

  The paper feed roller 312 takes out the recording medium P in the paper feed cassette 200 one by one. The guide plate 316 guides the recording medium P taken out by the paper feed roller 312 to the first transport roller pair 313.

  The first transport roller pair 313 feeds the recording medium P guided by the guide plate 316 to the paper transport path 311. Specifically, it is as follows. The first transport roller pair 313 includes a feed roller 313a and a retard roller 313b. The feed roller 313a and the retard roller 313b face each other and are pressed against each other. The feed roller 313a rotates and sends the recording medium P in the transport direction D. The retard roller 313b rotates following the feed roller 313a when one recording medium P is fed. On the other hand, when a plurality of recording media P are sent in a superimposed manner, the retard roller 313b rotates or stops in the direction opposite to the direction in which the recording media P is sent out and comes into contact with the feed roller 313a. The other recording medium P is separated from the existing recording medium P. As a result, one recording medium P is sent out by the feed roller 313a.

  The second transport roller pair 314 transports the recording medium P sent by the first transport roller pair 313 toward the registration roller pair 315 with the recording medium P interposed therebetween. The registration roller pair 315 performs skew correction of the recording medium P that has stopped in contact with the registration roller pair 315. Then, the registration roller pair 315 temporarily waits for the recording medium P in order to synchronize the printing timing and the conveyance of the recording medium P, and then the second paper conveyance unit 350 according to the printing timing. To send.

  The second paper transport unit 350 includes a speed detection roller 351, a suction roller 352, a drive roller 353, a tension roller 354, a pair of guide rollers 356, an endless transport belt 355, and a suction unit 360. . The conveyor belt 355 is stretched around a speed detection roller 351, a driving roller 353, a tension roller 354, and a pair of guide rollers 356. In this specification, the surface of the transport belt 355 on which the recording medium P is placed is referred to as a transport surface, and the surface facing the transport surface is referred to as a transport back surface. The rotation axis of each roller such as the drive roller 353 is parallel to the X axis. A plurality of suction holes are formed in the transport belt 355. Each of the plurality of suction holes penetrates from the transport surface to the transport back surface.

  The speed detection roller 351 is disposed upstream of the guide member 362 in the transport direction D of the recording medium P. The speed detection roller 351 includes a pulse plate (not shown). The speed detection roller 351 rotates in contact with the transport belt 355. By measuring the rotation speed of the pulse plate that rotates integrally with the speed detection roller 351, the rotation speed of the conveyor belt 355 is detected. The speed detection roller 351 suppresses the influence of the meandering correction of the conveyance belt 355 below the recording head 390.

  The suction roller 352 is fixed to the housing of the second paper transport unit 350 so as to face the upstream end of the guide member 362 in the transport direction D. The suction roller 352 is arranged so that the axis of the suction roller 352 is parallel to the transport surface of the transport belt 355 and orthogonal to the transport direction of the recording medium P. The suction roller 352 transports the recording medium P in the transport direction D while pressing the recording medium P against the transport belt 355 and the guide member 362. The suction roller 352 reduces curling of the recording medium P so that the entire recording medium P is evenly sucked by the suction unit 360. As a result, the adhesion of the recording medium P to the conveyance belt 355 can be improved.

  In order to mitigate the collision vibration to the suction roller 352 when the recording medium P enters the suction roller 352, the inertia moment of the suction roller 352 is preferably small, and the suction roller 352 is preferably light. For example, the suction roller 352 is formed using a hollow pipe made of aluminum or a hollow pipe using a plurality of ribs. When the surface of the adsorption roller 352 is formed of aluminum, it is preferable to perform an alumite treatment in order to suppress wear on the surface of the adsorption roller 352. Here, the alumite treatment means that the surface of aluminum is electrochemically oxidized to form an aluminum oxide film by electrolysis in an acidic treatment bath using aluminum as an anode. The adsorption roller 352 is electrically insulated by the alumite treatment. However, when the suction roller 352 requires conductivity, the surface of the suction roller 352 is not subjected to an alumite treatment.

  A difference between the conveyance speed of the recording medium P by the registration roller pair 315 and the conveyance speed of the recording medium P by the conveyance belt 355 may occur. However, the suction roller 352 applies a pressing force to the recording medium P on the transport belt 355 and bends the recording medium P between the registration roller pair 315 and the suction roller 352, thereby eliminating the difference in transport speed. can do.

  The drive roller 353 is arranged with a gap in the transport direction D of the recording medium P with respect to the speed detection roller 351. The conveyance belt 355 on the guide member 362 is maintained flat by the speed detection roller 351 and the driving roller 353. The driving roller 353 is in close contact with the transport belt 355 by a frictional force. For example, when the conveyor belt 355 is formed of a resin such as polyimide (PI), polyamideimide (PAI), polyvinylidene fluoride (PVDF), or polycarbonate (PC), ethylene propylene is formed on the surface of the driving roller 353. It is preferable to wind a rubber material such as diene (EPDM), polyurethane resin, or nitrile rubber (NBR). In particular, when the image forming unit 30 forms an image on the recording medium P using water-based ink, ethylene propylene diene (EPDM) is wound around the driving roller 353 in order to suppress swelling of the rubber material wound around the driving roller 353. It is preferable.

  When the conveyance belt 355 includes a rubber material such as ethylene propylene diene (EPDM), the surface of the driving roller 353 may be formed of metal. When the surface of the driving roller 353 is formed of aluminum, it is preferable to subject the surface of the driving roller 353 to alumite treatment in order to suppress wear on the surface of the driving roller 353. The drive roller 353 is electrically insulated by the alumite treatment. However, when the driving roller 353 needs to be conductive, the surface of the driving roller 353 is not subjected to an alumite treatment. Note that in the case where the driving roller 353 and the transport belt 355 are electrically connected, the transport belt 355 can be electrically grounded to suppress a decrease in ink flying accuracy. In this case, conductivity is imparted to the rubber material forming the conveyor belt 355.

  The driving roller 353 is rotationally driven by a motor (not shown), and rotates the conveyor belt 355 counterclockwise. If the speed of the transport belt 355 is uneven, speed unevenness correction control may be executed on the transport belt 355. The speed unevenness correction control is a control for correcting the speed unevenness of the transport belt 355 to make the speed of the transport belt 355 constant. When executing the speed unevenness correction control, it is preferable that the moment of inertia of the driving roller 353 is small, and the driving roller 353 is preferably light. For example, the driving roller 353 is formed using a hollow pipe made of aluminum or a hollow pipe using a plurality of ribs. On the other hand, when the speed unevenness correction control is not executed, it is preferable to increase the weight of the drive roller 353 in order to stabilize the rotation operation of the drive roller 353 by the flywheel effect due to inertia. In this case, the drive roller 353 is formed using a solid metal.

  The tension roller 354 is disposed at the upstream end of the conveyance belt 355 with respect to the guide member 362. The tension roller 354 applies tension to the transport belt 355 so that the transport belt 355 does not bend. By changing the position of one end of the tension roller 354, automatic meandering correction of the conveyor belt 355 is executed.

  The conveyance belt 355 conveys the recording medium P adsorbed on the conveyance belt 355. The conveyor belt 355 is preferably formed of, for example, polyamideimide (PAI) or polyimide (PI). In this case, unevenness in the thickness of the conveyor belt 355 is suppressed.

  The pair of guide rollers 356 are disposed below the suction part 360. The pair of guide rollers 356 are fixedly arranged to maintain a space surrounded by the inner peripheral surface (conveyance back surface) of the conveyance belt 355. Of the pair of guide rollers 356, the guide roller 356 close to the drive roller 353 maintains the amount of winding of the conveyor belt 355 around the drive roller 353. Of the pair of guide rollers 356, the guide roller 356 close to the tension roller 354 stably performs meandering correction of the transport belt 355, and thus maintains the amount of winding of the transport belt 355 around the tension roller 354.

The suction unit 360 is disposed on the conveyance rear surface side of the conveyance belt 355 so as to face the recording head 390 with the conveyance belt 355 interposed therebetween. The suction unit 360 includes an air circulation chamber 361, a guide member 362, and one or a plurality of suction devices 363. The air circulation chamber 361 has a hollow box shape with an opening in the upper part. The guide member 362 covers the upper surface opening of the air circulation chamber 361. The suction device 363 is disposed in communication with the air circulation chamber 361 and sucks the air in the air circulation chamber 361 to generate a negative pressure in the air circulation chamber 361. As a result, the recording medium P is sucked into the upper part of the air circulation chamber 361 through the transport belt 355 and the guide member 362. The suction device 363 is a fan, for example. Here, the negative pressure is a pressure lower than the reference pressure. In this specification, the reference pressure is atmospheric pressure. When the negative pressure is expressed as “P _N ”, the absolute pressure is expressed as “P _A ”, and the reference pressure is expressed as “P _R ”, the negative pressure P _N is an absolute value of (P _A −P _R ) (P _N = | P _A- P _R |). Absolute pressure is the pressure when the absolute vacuum is zero. The air circulation chamber 361 functions as a decompression chamber.

  The paper discharge unit 40 includes a conveyance guide 400, a discharge roller pair 410, and a discharge tray 420. The transport guide 400 is disposed downstream of the second paper transport unit 350 in the transport direction D of the recording medium P. The discharge tray 420 is fixed to the apparatus housing 10 so as to protrude outward from a discharge port 430 formed in the apparatus housing 10.

  The conveyance guide 400 guides the recording medium P conveyed from the conveyance belt 355 to the discharge roller pair 410. The recording medium P that has passed through the conveyance guide 400 is sent out in the direction of the discharge port 430 by the discharge roller pair 410 and is discharged to the discharge tray 420 through the discharge port 430.

  The recording head 390 includes one or more inkjet heads 390k, one or more inkjet heads 390c, one or more inkjet heads 390m, and one or more inkjet heads 390y. Each of the inkjet heads 390k, 390c, 390m, and 390y ejects ink.

  Each inkjet head 390k, each inkjet head 390c, each inkjet head 390m, and each inkjet head 390y is a line head, and includes a large number of nozzles (not shown). A large number of nozzles are formed on each nozzle surface of each inkjet head 390k to each inkjet head 390y. The nozzle surface of each inkjet head 390k faces the guide member 362. The same applies to the nozzle surfaces of the inkjet heads 390c to 390y. The recording head 390 is called a line type.

  Each of the multiple nozzles of the inkjet head 390k communicates with a pressurizing chamber (not shown) formed in the inkjet head 390k. The pressurizing chamber communicates with an ink liquid chamber (not shown) formed in the inkjet head 390k. The ink liquid chamber is connected to a black (K) ink tank (not shown) through an ink supply tube (not shown). Accordingly, a large number of nozzles of the inkjet head 390k eject black (K) ink.

  Each configuration of the inkjet head 390c to the inkjet head 390c is the same as the configuration of the inkjet head 390k. However, the inkjet head 390c is connected to a cyan (C) ink tank (not shown) and ejects cyan (C) ink. The inkjet head 390m is connected in communication with an ink tank (not shown) of magenta (M), and ejects magenta (M) ink. The inkjet head 390y is connected in communication with a yellow (Y) ink tank (not shown) and ejects yellow (Y) ink.

  As shown in FIG. 2, the guide member 362 is formed with a plurality of grooves 364a. Each of the plurality of grooves 364a has an oval shape in plan view, and extends along the conveyance direction D. The plurality of grooves 364a are arranged along the transport direction D and the direction orthogonal to the transport direction D. Each of the plurality of grooves 364a has a through hole 365a. Each of the plurality of through holes 365a is formed at a substantially central portion, one end portion, or the other end portion of the groove 364a. Each of the plurality of through holes 365 a is formed in a region other than the region facing the suction roller 352 of the guide member 362. Each of the plurality of through holes 365 a communicates with the air circulation chamber 361.

  As shown in FIG. 3, the guide member 362 has a double wall shape including an upper wall 364 and a lower wall 365. The upper wall 364 is disposed at a position closer to the recording head 390 than the lower wall 365. Accordingly, the groove 364a is opened toward the recording head 390. A plurality of grooves 364a are formed in the upper wall 364, and through holes 365a are formed in the lower wall 365 corresponding to the plurality of grooves 364a. The through hole 365a is formed so as to penetrate the lower wall 365 along the thickness direction of the lower wall 365. The thickness direction is a direction along the Z axis.

  When the suction device 363 is driven in a state where the recording medium P is placed on the conveyance surface of the conveyance belt 355, a negative pressure with respect to the atmospheric pressure is generated in the air circulation chamber 361. The negative pressure acts on the recording medium P through the plurality of through holes 365 a and the plurality of grooves 364 a of the guide member 362 and the plurality of suction holes of the transport belt 355. Accordingly, the recording medium P is sucked onto the conveyance surface of the conveyance belt 355. The recording medium P is transported in the transport direction D as the transport belt 355 rotates.

  With reference to FIG.2 and FIG.4, the effect | action and effect of this embodiment are demonstrated. FIG. 4 is a plan view of a guide member 362 'of a conventional transport device. In the guide member 362 'shown in FIG. 4, portions corresponding to those of the guide member 362 of the present embodiment shown in FIG.

  In the guide member 362 ′, two through holes 365a are provided in each of the plurality of grooves 364a positioned at the uppermost stream in the transport direction D, and the upstream side in the transport direction D of the two through holes 365a. A through-hole 365a (hereinafter referred to as "the most upstream through-hole 365a") is located opposite to the suction roller 352. Since the suction roller 352 presses the recording medium against the conveyance belt, the possibility that the recording medium is lifted from the conveyance belt is low even without the most upstream through hole 365a.

  Therefore, in the guide member 362 of the present embodiment shown in FIG. 2, instead of providing the through hole 365 a in the region facing the suction roller 352, the downstream end of each of the plurality of grooves 364 a located at the most downstream in the transport direction D A through hole 365a is provided. In this case, no negative pressure is applied to the region of the conveyor belt 355 facing the suction roller 352, and negative pressure is applied to the region facing the downstream end of the guide member 362. When the through hole 365 a is not provided at the downstream end of the guide member 362, the recording medium P is easily lifted from the conveyance belt 355 in a region of the conveyance belt 355 facing the downstream end of the guide member 362. In the guide member 362 of the present embodiment, the lifting of the recording medium P from the conveyance belt 355 can be effectively suppressed without increasing the number of through holes 365a as compared with the guide member 362 'shown in FIG.

  The embodiment of the present invention has been described above with reference to the drawings (FIGS. 1 to 4). However, the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist thereof (for example, (1) to (6) shown below). In order to facilitate understanding of the drawings, the thickness, length, number, and the like of each component are different from the actual for convenience of drawing. Moreover, the shape, dimension, etc. of each component shown by said embodiment are an example, Comprising: It does not specifically limit, A various change is possible in the range which does not deviate substantially from the effect of this invention.

  (1) As described with reference to FIGS. 1 and 2, in the present embodiment, the case where the pressing member is a roller has been described. However, the pressing member is a member other than the roller (for example, curved in a cross-sectional arc shape). A plate-like member).

  (2) As described with reference to FIGS. 2 and 3, in this embodiment, the groove and the through hole are formed in the guide member, but only the through hole may be formed in the guide member.

  (3) As described with reference to FIG. 1, in the present embodiment, the recording head is configured by a four-color inkjet head, but the recording head may be configured by a single-color inkjet head, You may be comprised with the inkjet head of multiple colors other than four colors.

  (4) As described with reference to FIG. 2, in this embodiment, the through holes are formed in all of the plurality of grooves, but the through holes may be formed in a part of the plurality of grooves. .

  (5) As described with reference to FIGS. 1 to 3, in the present embodiment, the case where the present invention is applied to a conveyance device of an ink jet recording apparatus has been described. For example, the present invention can also be applied to a transfer device of an electrophotographic image forming apparatus).

  (6) As described with reference to FIGS. 1 to 3, in the present embodiment, the case where the present invention is applied to an inkjet recording apparatus has been described. However, the present invention is not limited to other image forming apparatuses (for example, electrophotography). It can also be applied to an image forming apparatus).

  The present invention can be used in the field of image forming apparatuses.

1 Inkjet recording device 300 Conveying device 352 Adsorption roller (pressing member)
355 Conveying belt 360 Suction unit 362 Guide member 363 Suction device 364a Groove 365a Through hole 390 Recording head 390k, 390c, 390m, 390y Inkjet head P Recording medium

Claims (6)

A transport device for transporting a recording medium,
A conveyor belt for supporting the recording medium;
A pressing member that presses the recording medium onto the transport belt;
A suction section for sucking the recording medium through the transport belt,
The suction unit includes a guide member that supports the recording medium via the transport belt,
The guide member has a through hole that applies a negative pressure to the recording medium,
The said through-hole is a conveying apparatus formed in the area | regions other than the area | region which opposes the said press member among the said guide members.
The transport device according to claim 1, wherein the suction unit further includes an air circulation chamber and a suction device.
The transport apparatus according to claim 1, wherein the pressing member is a roller.
A plurality of grooves are formed in the guide member,
The conveying apparatus according to any one of claims 1 to 3, wherein the through hole is formed in at least one of the plurality of grooves.
The transport apparatus according to any one of claims 1 to 4,
An image forming apparatus comprising: a recording head that performs recording on the recording medium.
  The image forming apparatus according to claim 5, wherein the recording head includes an inkjet head that ejects ink.