JP2015199269A - Conveying device and ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveying device and an ink jet recording device capable of suppressing the adhesion of paper powder to a recording head with a simple configuration.SOLUTION: A conveying device 300 comprises a conveyor belt 355 and a suction part 360. The suction part 360 sucks a recording medium P through the conveyor belt 355. The suction part 360 includes an air circulation chamber 362 and a guide member 361. The air circulation chamber 362 is disposed on one surface side of the conveyor belt 355. In the air circulation chamber 362, negative pressure for sucking the recording medium P to the other surface side of the conveyor belt 355 is generated. The guide member 361 covers the air circulation chamber 362 and supports the recording medium P through the conveyor belt 355. A bottom surface of the air circulation chamber 362 comprises a first region A1 and a second region A2 which face a recording head 390 through the conveyor belt 355 and the guide member 361. A first distance L1 between the first region A1 of the bottom surface and the guide member 361 is smaller than a second distance L2 between the second region A2 of the bottom surface and the guide member 361.

Description

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

  In general, a printing apparatus (inkjet recording apparatus) is equipped with a conveying apparatus that conveys paper (an example of a recording medium). In the transport device, for example, fibers and fillers are peeled from the paper and paper dust is generated by contact, rubbing, and friction between the paper feed roller, the transport roller, or the paper guide plate and the paper. The paper dust adheres to the paper and is carried to just below the recording head of the printing apparatus.

  In addition, paper dust attached to the paper being transported may temporarily adhere to the cylindrical rubber area of the transport roller, and paper dust attached to the rubber area may be re-attached to the paper transported next by the transport roller. is there. As a result, a large amount of paper dust may adhere to the paper and be carried to just below the recording head.

  In the printing apparatus, an air flow (air flow) is generated and paper dust rises. As a result, the contamination in the printing apparatus is enlarged. That is, the printing apparatus includes a type that conveys paper by suction and suction. In this type of printing apparatus, a plurality of suction holes are formed in the conveyance belt. Then, the air on the conveyance belt is sucked from the plurality of suction holes, and the sheet is adsorbed on the conveyance belt. In the printing apparatus, an air flow is generated from the upper side of the conveyor belt to the lower side of the conveyor belt through the suction holes due to the suction of air from the suction holes. In addition, when the paper is transported, an air flow is also generated in the paper transport direction. Accordingly, a strong airflow is always generated between the transport belt and the recording head, and the transported paper passes under the recording head while being exposed to the airflow. As a result, under the recording head, the paper dust easily rises (is easily blown off) from the paper by the air current, and the contamination in the printing apparatus due to the paper dust increases.

  In general, paper dust may cause the following disadvantages to the printing apparatus. Since the recording head is disposed immediately above the conveyance belt with an interval through which the sheet can pass, the recording head is close to the conveyance belt. When the paper passes below the recording head, the paper dust may be conveyed along with the conveyance of the paper, and the paper dust may adhere to the nozzles formed on the recording head. As a result, the nozzles are clogged and ink non-ejection is likely to occur, and a defect may occur in the image formed on the paper.

  Therefore, the ink jet printer described in Patent Document 1 includes a paper dust removing device. The paper dust removing device includes a housing, a static elimination brush that neutralizes the paper, and an air blower that blows air on the static eliminated paper. The housing is arranged upstream of the printing area. The neutralizing brush and the air blower are disposed in the housing. Therefore, it is possible to suppress the paper dust attached to the paper from flying in the casing upstream of the printing area and attaching the paper dust to the recording head.

JP 2011-183746 A

  However, the configuration of the paper dust removing device provided in the ink jet printer described in Patent Document 1 is complicated.

  The present invention has been made in view of the above problems, and an object thereof is to provide a transport apparatus and an ink jet recording apparatus that can suppress adhesion of paper dust to a recording head with a simple configuration.

  According to the first aspect of the present invention, the transport device is disposed to face the recording head. The transport device includes a transport belt and a suction unit. The conveyance belt conveys the recording medium. The suction unit sucks the recording medium through the transport belt. The suction part includes an air circulation chamber and a guide member. The air circulation chamber is disposed on one surface side of the transport belt. A negative pressure is generated in the air circulation chamber to suck the recording medium toward the other surface of the transport belt. The guide member covers the air circulation chamber and supports the recording medium via the conveyance belt. The bottom surface of the air circulation chamber has a first region and a second region facing the recording head via the transport belt and the guide member. A first distance between the first region of the bottom surface and the guide member is smaller than a second distance between the second region of the bottom surface and the guide member.

  According to a second aspect of the present invention, an ink jet recording apparatus includes the transport device according to the first aspect of the present invention and the recording head. The recording head includes an inkjet head that ejects ink.

  According to the present invention, the first distance between the first region of the bottom surface of the air circulation chamber facing the recording head and the guide member is the first distance between the second region of the bottom surface and the guide member. Less than 2 distances. Accordingly, air circulation is suppressed in the first region. As a result, with a simple configuration, it is possible to suppress paper dust rising in the first region and reduce nozzle clogging of the recording head.

It is a schematic diagram which shows schematic structure of the inkjet recording device provided with the conveying apparatus which concerns on Embodiment 1 of this invention. It is a top view which shows the air circulation chamber of the conveying apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing along the III-III line | wire shown in FIG. It is a top view which shows the air circulation chamber of the conveying apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing along the VV line shown in FIG. It is a top view which shows the air circulation chamber of the conveying apparatus which concerns on Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof is not repeated.

(Embodiment 1)
[Basic principle]
With reference to FIGS. 1-3, the basic principle of the conveying apparatus 300 which concerns on Embodiment 1 of this invention is demonstrated. FIG. 1 shows a schematic configuration of an inkjet recording apparatus 1. The ink jet recording apparatus 1 includes a transport device 300 and a recording head 390. The conveyance device 300 is disposed to face the recording head 390.

  The transport apparatus 300 includes a transport belt 355 and a suction unit 360. The conveyance belt 355 conveys the recording medium P. The suction unit 360 sucks the recording medium P via the transport belt 355. The suction part 360 includes an air circulation chamber 362 and a guide member 361. The air circulation chamber 362 is disposed on one side of the transport belt 355 that is different from the transport surface of the recording medium P. In the air circulation chamber 362, a negative pressure is generated that sucks the recording medium P toward the other surface of the transport belt 355. The guide member 361 covers the air circulation chamber 362 and supports the recording medium P via the conveyance belt 355.

  FIG. 2 shows the air circulation chamber 362. The bottom surface of the air circulation chamber 362 has a first area A1 and a second area A2 that face the recording head 390 with the conveying belt 355 and the guide member 361 interposed therebetween. FIG. 3 shows a cross section of the air circulation chamber 362 along the line III-III shown in FIG. The first distance L1 between the first region A1 on the bottom surface and the guide member 361 is smaller than the second distance L2 between the second region A2 on the bottom surface and the guide member 361.

  According to the first embodiment, the first distance L1 between the first region A1 on the bottom surface of the air circulation chamber 362 facing the recording head 390 and the guide member 361 is equal to the second region A2 on the bottom surface and the guide. It is smaller than the second distance L <b> 2 between the member 361. Accordingly, the negative pressure in the space having the first area A1 as the bottom surface is smaller than the negative pressure in the space having the second area A2 as the bottom surface, and air flow is suppressed immediately below the recording head facing the first area A1. . As a result, with a simple configuration, the rising of the paper dust immediately below the recording head 390 is suppressed, and the adhesion of paper dust to the recording head 390 can be suppressed.

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.

[Configuration of Inkjet Recording Apparatus 1]
The ink jet 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 has a substantially C-shaped paper transport path 311. The first paper transport unit 310 includes a paper feed roller 312 disposed above one end of the paper feed cassette 200, a first transport roller pair 313 provided on the entrance side of the paper transport path 311, and a paper transport path 311. Are provided with a second conveying roller pair 314 provided in the middle, a registration roller pair 315 provided on the exit side of the sheet conveying path 311, and a guide plate 316.

  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 361. The Z axis is parallel to the direction orthogonal to the guide member 361. 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 guide plate 316 is disposed between the paper feed roller 312 and the first transport roller pair 313. 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, a surface of the transport belt 355 on which the recording medium P is placed is described as a transport surface, and a surface facing the transport surface is described 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 (not shown) are formed in the transport belt 355. Each of the plurality of suction holes penetrates from the conveyance surface to the conveyance back surface.

  The speed detection roller 351 is disposed upstream of the guide member 361 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 disposed at the upstream end in the transport direction D of the guide member 361 via the transport belt 355. 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 361. 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 refers to a surface treatment in which the surface of aluminum is used as an anode and is oxidized and coated mainly by electrolysis of water in a strong acid. The adsorption roller 352 is electrically insulated by the alumite treatment. However, when the suction roller 352 needs to have conductivity, the surface of the suction roller 352 may not be anodized.

  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 361 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. Note that, when 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 361. 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 a guide member 361, an air circulation chamber 362, and one or a plurality of suction devices 363. The guide member 361 covers the upper surface opening of the air circulation chamber 362. The air circulation chamber 362 has a hollow box shape with an opening formed in the upper part. The suction device 363 is disposed in communication with the air circulation chamber 362 and sucks the air in the air circulation chamber 362 to generate a negative pressure in the air circulation chamber 362. As a result, the recording medium P is sucked into the upper part of the air circulation chamber 362 through the conveyance belt 355 and the guide member 361. The air circulation chamber 362 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 discharged 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.

[Configuration of Recording Head 390]
The configuration of the recording head 390 will be described in detail with reference to FIG. 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.

  In the first embodiment, the recording head 390 is described as three inkjet heads 390k (may be described as one set of inkjet heads 390k), and three inkjet heads 390c (as described as one set of inkjet heads 390c). 3) Ink jet heads 390m (may be described as one set of ink jet heads 390m) and three ink jet heads 390y (may be described as one set of ink jet heads 390y). Is done.

  One set of inkjet heads 390k, 390c, 390m, and 390y are arranged in parallel from the upstream side to the downstream side in the transport direction D of the recording medium P. The three inkjet heads 390k are arranged in a staggered pattern along the width direction of the transport belt 355 (see FIG. 1). The three inkjet heads 390c to 390y are also arranged in the same manner as the three inkjet heads 390k.

  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 the nozzle surface of each inkjet head 390k to each inkjet head 390y. The nozzle surface of each inkjet head 390k faces the guide member 361. The same applies to the nozzle surfaces of the inkjet heads 390c to 390y. The recording head 390 is called a line type. Each inkjet head 390k to each inkjet head 390y extends along the width direction of the transport belt 355 (see FIG. 1).

  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, the large number of nozzles B of the inkjet head 390k eject black (K) ink.

  Each configuration of the inkjet head 390c to the inkjet head 390y 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.

[Suction unit 360]
The suction unit 360 will be described with reference to FIGS. The suction unit 360 includes a guide member 361, an air circulation chamber 362, and a suction device 363. First, the guide member 361 that covers the air circulation chamber 362 will be described. As shown in FIG. 3, a plurality of grooves 364 are formed in the guide member 361. The plurality of grooves 364 are open toward the recording head 390. A through hole 365 is formed at the bottom of each of the plurality of grooves 364. The through hole 365 passes through the guide member 361. Therefore, the groove 364 and the air circulation chamber 362 communicate with each other.

  Next, the air circulation chamber 362 will be described. As shown in FIG. 2, the air circulation chamber 362 has a rectangular shape in plan view. The air circulation chamber 362 has a box shape and includes an outer wall 367 and a bottom wall 368. The outer wall 367 is erected from the peripheral edge of the rectangular bottom wall 368. The bottom wall 368 includes a first area A1 that faces the recording head 390 (inkjet head 390k to inkjet head 390y) via the conveyor belt 355 and the guide member 361, and a plurality of second areas A2.

  Among the plurality of second regions A2, one second region A2 is a region between the outer wall 367 and the first region A1, and the other second region A2 is surrounded by the first region A1. The first area A1 and the second area A2 are adjacent to each other. Three openings 362a are formed in the second region A2 corresponding to the three suction devices 363 upstream of the first region A1 in the transport direction D. The three openings 362a are, for example, circular and are arranged linearly along the X axis.

  As shown in FIG. 3, the first region A1 corresponds to the convex portion formed on the bottom wall 368, and the second region A2 corresponds to the concave portion formed on the bottom wall 368. Therefore, the first distance L1 between the first region A1 and the guide member 361 is smaller than the second distance L2 between the second region A2 and the guide member 361. Each of the first region A1 and the second region A2 is, for example, a plane.

  Next, the suction device 363 will be described. As shown in FIG. 2, the suction device 363 is disposed below the corresponding opening 362a. That is, the suction device 363 is disposed in communication with the second region A2 of the air circulation chamber 362. In the first embodiment, three suction devices 363 are provided. Each of the suction devices 363 has a fan 363a. Each of the fans 363a is driven by a motor (not shown) so that the pressure in the air circulation chamber 362 becomes negative. In FIG. 3, the fan 363a is not shown for simplification of the drawing.

  Next, the operation of the suction unit 360 will be described. 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 is generated in the air circulation chamber 362. The negative pressure acts on the recording medium P via the plurality of through holes 365 and the plurality of grooves 364 of the guide member 361 and the plurality of suction holes (not shown) of the conveying 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.

  As shown in FIG. 3, the first distance L1 is smaller than the second distance L2. Therefore, the negative pressure (the negative pressure applied to the first region A1) of the space with the first region A1 in the bottom of the space of the air circulation chamber 362 is the bottom of the second region A2 of the space of the air circulation chamber 362. It is smaller than the negative pressure in the space (negative pressure applied to the second region A2). As a result, the difference between the pressure in the space with the first region A1 as the bottom surface (pressure applied to the first region A1) and the atmospheric pressure is the pressure in the space with the second region A2 as the bottom surface (pressure applied to the second region A2). ) And the atmospheric pressure, and the flow of air immediately below the recording head 390 is suppressed. Note that the pressure in the space on the conveyance surface side of the conveyance belt 355 (including the space immediately below the recording head 390) is atmospheric pressure. On the other hand, since the negative pressure in the space having the second region A2 as the bottom surface is large, it is possible to generate a suction force sufficient to suck the recording medium P.

[Function of the first area A1]
With reference to FIGS. 1-3, the function of 1st area | region A1 of the air circulation chamber 362 is demonstrated. A first distance L1 between the first region A1 facing the recording head 390 (inkjet head 390k to inkjet head 390y) and the guide member 361 is greater than a second distance L2 between the second region A2 and the guide member 361. small. Accordingly, the air flow immediately below the recording head 390 is suppressed.

  The reason why the first area A1 faces the recording head 390 in the present invention will be described. A negative pressure is generated in an air circulation chamber of a general suction unit. The guide member is formed with a plurality of grooves and a plurality of through holes over the entire area. Therefore, due to the air flow to the air circulation chamber through the plurality of grooves and the plurality of through holes, a large amount of paper dust of the recording medium is generated from the upstream in the conveyance direction of the recording medium from the image forming space. It is thought that will be carried to. The image forming space is a space between the recording head and the guide member. Further, it is considered that paper dust is also carried into the image forming space by the air flow accompanying the conveyance of the recording medium in the conveyance direction.

  The bottom wall of the air circulation chamber of a general suction part is a uniform plane. That is, a general air circulation chamber does not have a region corresponding to the first region A1, but has only a region corresponding to the second region A2. Accordingly, the negative pressure in the air circulation chamber is large, and the circulation of air directly below the recording head is also large. As a result, a large amount of paper dust is carried to the vicinity of the recording head, and the paper dust is likely to be blown off (easy to rise) immediately below the recording head, and eventually the nozzles of the recording head are blocked by the paper dust. When the nozzles are blocked, there is a possibility that an image formed on the recording medium may be defective.

  Therefore, in the first embodiment, the bottom surface of the air circulation chamber 362 has the first region A1 that faces the recording head 390, and suppresses the air flow directly under the recording head 390, thereby preventing the recording head 390. It is possible to prevent the paper dust from being drawn directly under the recording head or the paper dust from being blown off directly under the recording head 390. Therefore, adhesion of paper dust to the recording head 390 is suppressed. As a result, it is possible to suppress the occurrence of defects in the image formed on the recording medium P.

  In addition, the bottom surface of the air circulation chamber 362 has the first region A1, and by suppressing the air flow just below the recording head 390, it is possible to suppress image positional deviation and color deviation. Details will be described below.

  Generally, the configuration of the air circulation chamber of the suction unit is considered to be one factor that determines the accuracy of the positional deviation and color deviation of the image formed on the recording medium. Specifically, it is as follows. It is considered that the positional deviation and the color deviation of the image depend on the flying accuracy of the ink. The ink flying accuracy is affected by the air flow in the ink flying space (image forming space). If the air flow is fast, the ink is bent by the air flow. Therefore, the configuration of the air circulation chamber that affects the flow of air immediately below the recording head is considered to be a factor that determines the accuracy of ink flight, and thus the accuracy of image positional deviation and color deviation.

  Therefore, in the first embodiment, the bottom surface of the air circulation chamber 362 has the first region A1, and the air flying accuracy immediately below the recording head 390 is suppressed, thereby improving the ink flying accuracy. As a result, it is possible to suppress image positional deviation and color deviation.

  As described above with reference to FIGS. 1 to 3, according to the first embodiment, the first distance L1 between the first region A1 and the guide member 361 is set to the second region A2 and the guide member 361. By making the distance less than the second distance L2 between the two, the air flow is suppressed immediately below the recording head 390. Accordingly, drawing of paper dust directly below the recording head 390 and rising of paper dust immediately below the recording head 390 are suppressed, and adhesion of paper dust to the recording head 390 is suppressed. As a result, nozzle clogging of the recording head 390 is suppressed, and it is possible to suppress the occurrence of defects in the image formed on the recording medium P. Further, by having the second region A2, a sufficient suction force when sucking the recording medium P is secured.

(Embodiment 2)
A transport apparatus 300 according to Embodiment 2 of the present invention will be described with reference to FIGS. The configuration of the transport apparatus 300 according to the second embodiment is the same as the configuration of the transport apparatus 300 according to the first embodiment. However, the air circulation chamber 362 of the transfer apparatus 300 according to the second embodiment has a third area A3 in addition to the first area A1 and the second area A2. For example, the transport apparatus 300 according to the second embodiment is mounted on the ink jet recording apparatus 1 illustrated in FIG. 1 instead of the transport apparatus 300 according to the first embodiment. Hereinafter, differences between the second embodiment and the first embodiment will be mainly described.

  FIG. 4 shows the air circulation chamber 362 of the transfer apparatus 300 according to the second embodiment. In addition to the first area A1 and the plurality of second areas A2, the bottom surface of the air circulation chamber 362 is a feeding member (hereinafter referred to as “feeding member F” (refer to FIG. 1)) of the recording medium P. It has several 3rd area | region A3 through which the part which contact | connects passes. The plurality of third regions A3 are along the transport direction D. In FIG. 4, for convenience of explanation, the third area A3 is indicated by a broken line, but actually, the first area A1 and the third area A3 are not separated and are continuous areas.

  FIG. 5 shows a cross section of the air circulation chamber 362 along the line VV shown in FIG. In FIG. 5, the fan 363a is not shown for simplification of the drawing. The third distance L3 between the third region A3 on the bottom surface and the guide member 361 is smaller than the second distance L2 between the second region A2 on the bottom surface and the guide member 361. Accordingly, the negative pressure in the space having the bottom surface of the third region A3 is smaller than the negative pressure of the space having the bottom surface of the second region A2, and the air in the space through which the portion of the recording medium P in contact with the feeding member F passes. Distribution is suppressed. As a result, paper dust rises in a space through which a portion of the recording medium P that contacts the feeding member F passes is suppressed. Furthermore, since the first distance L1 is smaller than the second distance L2 as in the first embodiment, the negative pressure in the first area A1 is smaller than the negative pressure in the second area A2, and air flows directly under the recording head 390. Is suppressed.

  In the second embodiment, the first distance L1 and the third distance L3 are equal. Accordingly, the first area A1 and the third area A3 are continuous planes. As a result, the air circulation chamber can be easily designed and manufactured.

  With reference to FIG. 1, the arrangement and width of the third region A <b> 3 will be described in association with the feed member F. The feeding member F conveys the recording medium P. The feed member F is provided in the transport device 300. The feed member F includes a paper feed roller 312, a first transport roller pair 313, or a second transport roller pair 314.

  The feeding member F is disposed upstream of the guide member 361 in the transport direction D of the recording medium P. The width of the feeding member F is smaller than the width of the smallest recording medium P that can be conveyed, for example. The width of the feeding member F is, for example, substantially the same as the width along the longitudinal direction of one inkjet head 390k or smaller than the width along the longitudinal direction of one inkjet head 390k. The width of the feeding member F is the width of the portion in contact with the recording medium P and indicates the width along the rotation axis of the feeding member F. The width of the recording medium P indicates a width along a direction orthogonal to the transport direction D.

  The bottom surface of the air circulation chamber 362 has a third region A3 corresponding to the portion of the recording medium P that contacts the feeding member F. In the second embodiment, the width of the third region A3 is substantially the same as the width of the feed member F or slightly larger than the width of the feed member F. The width of the third region A3 indicates a width along a direction orthogonal to the transport direction D.

  The feeding member F is arranged so that a region corresponding to the center line of the recording medium P is in contact with the feeding member F. Here, the center line of the recording medium P indicates a center line along the transport direction D of the recording medium P. Accordingly, the bottom surface of the air circulation chamber 362 has a plurality of third regions A3 along the transport direction D corresponding to the center line of the recording medium P.

  The reason why the air circulation chamber 362 has the third region A3 corresponding to the feeding member F will be described. The paper feed roller 312 slips on the contact surface with the recording medium P when taking out the recording medium P from the paper feeding cassette 200. In addition, the recording medium P picked up by the paper feed roller 312 and the recording medium P stacked immediately below it rub against each other. Therefore, it is considered that paper dust is likely to be generated in the vicinity of the paper feed roller 312.

  The retard roller 313b of the first transport roller pair 313 suppresses double feed by driving and rotating in the direction opposite to the transport direction D of the recording medium P or by stopping. Therefore, it is considered that paper dust is likely to be generated in the vicinity of the first conveying roller pair 313.

  The width of the second transport roller pair 314 is smaller than the width of the recording medium P. Therefore, each roller rotates while the edge of each roller of the second transport roller pair 314 is in contact with the recording medium P. Since the edges of each roller are relatively sharp, it is considered that paper dust is likely to be generated in the vicinity of the second conveying roller pair 314. The same applies to the paper feed roller 312 and the first transport roller pair 313.

  As described above, it is considered that paper dust is more likely to adhere to the portion of the recording medium P that contacts the feeding member F than the portion that passes without contacting the feeding member F. Therefore, in the second embodiment, a third area A3 is defined through which the portion of the recording medium P that contacts the feeding member F passes, and the portion of the recording medium P in which the paper dust easily adheres passes. Control air flow. As a result, the adhesion of paper dust to the recording head 390 is suppressed, and it is possible to suppress the occurrence of defects in the image formed on the recording medium P.

  Next, the detailed structure of the air circulation chamber 362 will be described. As shown in FIG. 4, the air circulation chamber 362 has a rectangular shape and includes an outer wall 367 and a bottom wall 368. The bottom wall 368 includes a first region A1, a second region A2, and a feeding member of the recording medium P that face the recording head 390 (inkjet head 390k to inkjet head 390y) via the conveyance belt 355 and the guide member 361. And a third region A3 through which a portion in contact with F passes.

  The first area A1 and the plurality of third areas A3 constitute a fourth area A4. The second area A2 is an area between the outer wall 367 and the fourth area A4. The fourth area A4 and the second area A2 are adjacent to each other.

  As shown in FIG. 5, the fourth region A4 corresponds to the convex portion formed on the bottom wall 368, and the second region A2 corresponds to the concave portion formed on the bottom wall 368. Accordingly, the first distance L1 between the first region A1 and the guide member 361 and the third distance L3 between the third region A3 and the guide member 361 are respectively between the second region A2 and the guide member 361. Less than the second distance L2. Each of 4th area | region A4 (1st area | region A1 and 3rd area | region A3) and 2nd area | region A2 is a plane, for example.

  Each of the first distance L1 and the third distance L3 is smaller than the second distance L2. Therefore, the negative pressure (the negative pressure applied to the fourth area A4) in the space of the air circulation chamber 362 having the fourth area A4 as the bottom surface is the second area A2 of the space of the air circulation chamber 362 as the bottom surface. It is smaller than the negative pressure in the space (negative pressure applied to the second region A2). As a result, the difference between the pressure in the space having the fourth region A4 as the bottom surface (pressure applied to the fourth region A4) and the atmospheric pressure is the pressure in the space having the second region A2 as the bottom surface (pressure applied to the second region A2). ) And the atmospheric pressure, and the air flow is suppressed in the space immediately below the recording head 390 and the space through which the portion of the recording medium P where paper dust easily adheres passes. Note that the pressure in the space on the conveyance surface side of the conveyance belt 355 (including the space immediately below the recording head 390) is atmospheric pressure. On the other hand, since the negative pressure in the space having the second region A2 as the bottom surface is large, it is possible to generate a suction force sufficient to suck the recording medium P.

  As described above, according to the second embodiment, in addition to the first area A1, the air circulation chamber 362 has the third area A3 corresponding to the portion of the recording medium P where paper dust is likely to be generated. The third distance L3 between the third region A3 and the guide member 361 is smaller than the second distance L2. Accordingly, not only the negative pressure in the space having the first area A1 as the bottom surface, but also the negative pressure in the space having the third area A3 as the bottom surface is reduced, and the paper powder in the space immediately below the recording head 390 and the recording medium P is recorded. In the space through which the portion where the air is easily generated passes, the circulation of air is suppressed. As a result, adhesion of paper dust to the recording head 390 is further suppressed, and nozzle clogging can be further suppressed. Further, since the bottom surface of the air circulation chamber 362 has the second region A2, a sufficient suction force when the recording medium P is sucked is ensured.

(Embodiment 3)
A transport apparatus 300 according to Embodiment 3 of the present invention will be described with reference to FIGS. The configuration of the transport apparatus 300 according to the third embodiment is the same as the configuration of the transport apparatus 300 according to the second embodiment. However, the first area A1 of the transport apparatus 300 according to the third embodiment includes a plurality of inkjet heads (for example, three) that eject the same color ink included in the recording head 390 via the transport belt 355 and the guide member 361. Part of the recording medium P of the recording head P facing the feeding head F. For example, the transport apparatus 300 according to the third embodiment is mounted on the ink jet recording apparatus 1 illustrated in FIG. 1 instead of the transport apparatus 300 according to the first embodiment. Hereinafter, differences between the third embodiment and the second embodiment will be mainly described.

  FIG. 6 shows the air circulation chamber 362 of the transfer apparatus 300 according to the third embodiment. The cross section of the air circulation chamber 362 along the line VV shown in FIG. 6 is the same as the cross section of the air circulation chamber 362 shown in FIG. In FIG. 6, for convenience of explanation, the third area A3 is indicated by a broken line, but actually, the first area A1 and the third area A3 are not separated and are continuous areas. The first region A1 and the plurality of third regions A3 constitute a fifth region A5.

  The first area A1 includes a central inkjet head 390k, a central inkjet head 390c, a central inkjet head 390m, a central inkjet head 390c through which a portion of the recording medium P that contacts the feeding member F passes through the conveyance belt 355 and the guide member 361. And the central inkjet head 390y. Accordingly, the fifth area A5 is an area through which the portion of the recording medium P that contacts the feeding member F passes.

  In the third embodiment, as shown in FIG. 5, the first distance L1 and the third distance L3 are equal. Therefore, the fifth area A5 is one rectangular continuous plane. As a result, the air circulation chamber can be easily designed and manufactured.

  The fifth region A5 corresponds to the convex portion formed on the bottom wall 368, and the second region A2 corresponds to the concave portion formed on the bottom wall 368. Accordingly, the first distance L1 between the first region A1 and the lower surface of the guide member 361 and the third distance L3 between the third region A3 and the lower surface of the guide member 361 are respectively the second region A2 and the guide member. It is smaller than the second distance L2 between the lower surface of 361. Each of the fifth region A5 (the first region A1 and the third region A3) and the second region A2 is, for example, a plane.

  As described above, according to the third embodiment, as in the second embodiment, the air circulation chamber 362 includes the first region A1 and the third region A3. As a result, as in the second embodiment, the adhesion of paper dust to the recording head 390 is suppressed, and nozzle clogging can be suppressed. The first region A1 faces the inkjet head through which the portion of the recording medium P that contacts the feeding member F among the plurality of inkjet heads 390k to 390y passes. Therefore, the area of the second area A2 is increased compared with the case where the first area A1 faces all the ink jet heads 390k to 390y, and the suction force when sucking the recording medium P can be increased. it can.

  The embodiment of the present invention has been described above with reference to the drawings (FIGS. 1 to 6). 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 (8) shown below). In order to facilitate understanding, the drawings schematically show each component as a main component, and the thickness, length, number, and the like of each component shown in the drawings 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. 2 and 4, the air circulation chamber 362 has the first region A <b> 1 facing all of the one set of inkjet heads 390 k to 390 y. However, the air circulation chamber 362 may have the first region A1 facing one set, two sets, or three sets of inkjet heads among one set of inkjet heads 390k to 390y. .

  (2) As described with reference to FIGS. 2, 4, and 6, the first region A1 faces the three inkjet heads 390k. However, the first region A1 may be opposed to one or two of the three inkjet heads 390k. The same applies to the other inkjet heads 390c to 390y.

  (3) As described with reference to FIGS. 2 and 4, the first area A1 faces the entire area of the nozzle surface of one inkjet head 390k. However, the first region A1 may face a partial region of the nozzle surface of one inkjet head 390k. The same applies to the other inkjet heads 390c to 390y.

  (4) As described with reference to FIGS. 4 and 6, the air circulation chamber 362 has four third regions A3. However, one third region A3 may be included, or a plurality of third regions A3 other than four may be included.

  (5) As described with reference to FIG. 1, the recording head 390 includes the four-color inkjet heads 390k to 390y. However, the recording head 390 may be configured with a single-color inkjet head, or may be configured with a plurality of colors of inkjet heads other than four colors. The first area A1 faces the ink jet head included in the recording head 390.

  (6) As described with reference to FIG. 2, three inkjet heads 390k are prepared for one color. However, a single inkjet head 390k may be prepared for one color, or a plurality of inkjet heads 390k other than three may be prepared. The same applies to the other inkjet heads 390c to 390y.

  (7) As described with reference to FIGS. 4 to 6, the first distance L1 and the third distance L3 are equal. However, the third distance L3 and the first distance L1 may be different. For example, the third distance L3 may be smaller than the first distance L1, and the third distance L3 may be larger than the first distance L1.

  (8) As described with reference to FIGS. 2, 4, and 6, the first area A1 is one area. However, the bottom surface of the air circulation chamber 362 may have a plurality of first regions A1. As described with reference to FIGS. 4 and 6, the first area A1 and the third area A3 are one plane. However, you may have 1st area | region A1 and 3rd area | region A3 isolate | separated.

  The present invention can be used in the field of image forming apparatuses such as a transport apparatus that transports a recording medium and an ink jet recording apparatus.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 200 Paper feed cassette 300 Transport device 312 Paper feed roller 313 First transport roller 314 Second transport roller 315 Registration roller pair 355 Transport belt 360 Suction unit 362 Air flow chamber 363 Suction device 390 Recording head P Recording medium

Claims (7)

A conveying device arranged to face the recording head,
A transport belt for transporting a recording medium;
A suction section for sucking the recording medium through the transport belt,
The suction part is
An air circulation chamber that is disposed on one surface side of the transport belt and generates a negative pressure for sucking the recording medium to the other surface side of the transport belt;
A guide member that covers the air circulation chamber and supports the recording medium via the transport belt,
The bottom surface of the air circulation chamber has a first region facing the recording head via the transport belt and the guide member, and a second region,
The conveying device, wherein a first distance between the first region of the bottom surface and the guide member is smaller than a second distance between the second region of the bottom surface and the guide member. A feed member for conveying the recording medium;
The feeding member is disposed upstream of the guide member in the transport direction of the recording medium,
The bottom surface of the air circulation chamber further includes a third region through which a portion of the recording medium in contact with the feeding member passes,
The transport apparatus according to claim 1, wherein a third distance between the third region of the bottom surface and the guide member is smaller than the second distance of the bottom surface.   The transport apparatus according to claim 2, wherein the first distance and the third distance are equal. The suction part further includes a suction device that generates a negative pressure in the air circulation chamber,
The said suction device is a conveying apparatus of any one of Claims 1-3 arrange | positioned in communication with the said 2nd area | region of the said air circulation chamber.   5. The transport device according to claim 1, wherein the first region faces a plurality of ink jet heads arranged in a staggered pattern included in the recording head. 6.   The first region is opposed to an inkjet head through which a portion of the recording medium that contacts the feeding member passes among a plurality of inkjet heads that discharge ink of the same color included in the recording head. The conveying apparatus as described. The transport apparatus according to any one of claims 1 to 6,
The recording head, and
The ink jet recording apparatus, wherein the recording head includes an ink jet head for discharging ink.

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