JP2015164784A - Conveying apparatus and inkjet recording apparatus - Google Patents

Abstract

Provided are a transport device and an ink jet recording apparatus capable of suppressing adhesion of paper dust to a recording head with a simple configuration. A transport apparatus is disposed to face a recording head. 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 a guide member 361. The guide member 361 supports the recording medium P via the conveyance belt 355. The guide member 361 is formed with at least one first groove 364a having no through hole 365b and a second groove 365b having a through hole 365b. The guide member 361 includes a first area A1 facing the recording head 390 and a second area A2 adjacent to the first area A1. The first region A1 is provided with at least one first groove 364a. A second groove 364b is provided in the second region A2. [Selection] Figure 2

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 disposed upstream of the printing region in the paper transport direction. 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 a guide member. The guide member supports the recording medium via the transport belt. The guide member is formed with at least one first groove having no through hole and a second groove having a through hole. The guide member has a first area facing the recording head and a second area adjacent to the first area. The at least one first groove is provided in the first region. The second groove is provided in the second region.

  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 groove that is not formed with the through hole is provided in the first region of the guide member facing the recording head. Accordingly, air flow is suppressed immediately below the recording head. As a result, with a simple configuration, the rising of paper dust immediately below the recording head is suppressed, and adhesion of paper dust to the recording head can be suppressed.

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 outline of the guide member of the conveying apparatus which concerns on Embodiment 1 of this invention. It is a top view which shows the detail of the guide member of the conveying apparatus which concerns on Embodiment 1 of this invention. FIG. 3 is a plan view illustrating a part of a recording head that is disposed to face the conveyance device according to the first embodiment of the invention. (A) It is sectional drawing to which the 1st area | region was expanded among the guide members of the conveying apparatus which concerns on Embodiment 1 of this invention. (B) It is sectional drawing to which the 2nd area | region was expanded among the guide members of the conveying apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the relationship between the number of non-ejection nozzles and the output sheet number of a recording medium in the conveying apparatus which concerns on Embodiment 1 of this invention, and a comparative example. (A) It is a top view which shows the 1st modification of the guide member of the conveying apparatus which concerns on Embodiment 1 of this invention. (B) It is a top view which shows the 2nd modification of the guide member of the conveying apparatus which concerns on Embodiment 1 of this invention. It is a top view which shows the outline of the guide member of the conveying apparatus which concerns on Embodiment 2 of this invention. It is a top view which shows the detail of the guide member of the conveying apparatus which concerns on Embodiment 2 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 that transports the recording medium P, and a suction unit 360 that sucks the recording medium P via the transport belt 355. The suction part 360 includes a guide member 361. The guide member 361 supports the recording medium P via the conveyance belt 355.

  FIG. 2 shows an outline of the guide member 361 of the transport apparatus 300. The guide member 361 includes a first area A1 facing the recording head 390 and a second area A2 adjacent to the first area A1. 2 and 3, the first region A1 is indicated by a thick solid line for convenience of explanation, but there is actually no solid line.

  FIG. 3 shows details of the guide member 361 of the transport apparatus 300. The guide member 361 is formed with at least one first groove 364a having no through hole 365b and a second groove 364b having a through hole 365b. In the first region A1 of the guide member 361, at least one first groove 364a is provided. A second groove 364b is provided in the second region A2 of the guide member 361.

  According to the first embodiment, the first groove A 364a in which the through hole 365b is not formed is provided in the first region A1 facing the recording head 390 of the guide member 361. Accordingly, air flow is suppressed immediately below the recording head 390. 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.

[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 transport surface to the transport 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 an oxide film is formed on the aluminum surface mainly by electrolysis of water in a strong acid using the aluminum surface as an anode. The adsorption roller 352 is electrically insulated by the 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 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 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. Each 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.

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 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 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.

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

  FIG. 4 shows the three inkjet heads 390k of the recording head 390 arranged to face the conveying device 300. The ink jet head 390k has a nozzle surface C. The nozzle surface C faces the guide member 361. On the nozzle surface C, a plurality of nozzle formation regions 391 are arranged along the X axis. A plurality of nozzles B are formed in the nozzle formation region 391. Each of the plurality of nozzle formation regions 391 has a trapezoidal shape. The plurality of nozzles B are arranged in a staggered pattern in the nozzle formation region 391 so that no blank is generated between adjacent recording dots when ink droplets are ejected onto the recording medium P.

  Each of the multiple nozzles B of the ink jet head 390k communicates with a pressurizing chamber (not shown) formed in the ink jet 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.

  As a method for ejecting ink from the recording head 390, for example, a piezo method for ejecting ink using a piezo element (not shown), or a thermal inkjet that generates air bubbles by a heating element and ejects ink by applying pressure. Various methods such as a method can be applied.

[Structure of guide member 361]
The guide member 361 will be described in detail with reference to FIGS. 2, 3, and 5. As shown in FIG. 2, the guide member 361 has a rectangular shape in the plan view of the inkjet recording apparatus 1. The guide member 361 includes three rectangular first areas A1 (sometimes referred to as “first areas A1k”) facing three rectangular inkjet heads 390k, and three rectangular inkjet heads. Three rectangular first areas A1 corresponding to the head 390c (sometimes referred to as “first area A1c”), three rectangular first areas A1 corresponding to the three rectangular inkjet heads 390m. 1 area A1 (may be referred to as “first area A1m”), and three rectangular first areas A1 (“first area A1y”) corresponding to the three rectangular inkjet heads 390y. May be described.)

  The three first regions A1k are arranged in a staggered pattern so as to face the three inkjet heads 390k arranged in a staggered pattern. The three first regions A1c are arranged in a staggered manner so as to face the three inkjet heads 390c arranged in a staggered manner. The three first regions A1m are arranged in a staggered manner so as to face the three inkjet heads 390m arranged in a staggered manner. The three first regions A1y are arranged in a staggered manner so as to face the three inkjet heads 390y arranged in a staggered manner. As shown in FIG. 2, a plurality of first areas A1 are provided, and the plurality of first areas A1 are arranged in a staggered pattern. Therefore, it is suitable for the inkjet heads 390k to 390y arranged in a staggered pattern.

  The guide member 361 has a plurality of second regions A2. In FIG. 2, broken lines are shown for the sake of clarity of the plurality of second regions A2, but there are actually no broken lines. Accordingly, in the present embodiment, the plurality of second regions A2 are formed as one continuous region. Each of the plurality of first regions A1 is adjacent to several second regions A2. In the first embodiment, each of the plurality of first regions A1 is adjacent to two second regions A2, three second regions A2, or four second regions A2.

  As shown in FIG. 3, a plurality of first grooves 364a are formed in each of the plurality of first regions A1. A plurality of second grooves 364b are formed in each of the plurality of second regions A2. Each of the first groove 364a and the second groove 364b has an oval shape and extends along the transport direction D. The plurality of first grooves 364a are arranged along the transport direction D and the direction perpendicular to the transport direction D. The plurality of second grooves 364b are arranged along the transport direction D and the direction perpendicular to the transport direction D. The first groove 364a functions as an ink tray, and can reduce the accumulation of ink between the conveyance belt 355 and the guide member 361. The second groove 364b can also function as an ink tray.

  Each of the plurality of second grooves 364b has one or a plurality of through holes 365b. In the first embodiment, one or two through holes 365b are formed in one second groove 364b. When one through hole 365b is formed in one second groove 364b, for example, the through hole 365b is disposed at one end, the other end, or the center of the second groove 364b. For example, the plurality of through holes 365b are formed in the plurality of second grooves 364b so as to be arranged in a staggered pattern along a direction orthogonal to the transport direction D. In the case where two through holes 365b are formed in one second groove 364b, for example, the two through holes 365b are disposed at both ends of the second groove 364b.

  Next, details of the first groove 364a, the second groove 364b, and the through hole 365b will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view of a part of the guide member 361. The guide member 361 is a top wall that covers the upper surface opening of the air circulation chamber 362. The guide member 361 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.

  FIG. 5A is a cross-sectional view in which the first region A1 of the guide member 361 is enlarged. In the first region A1, the upper wall 364 has a plurality of first grooves 364a. Each of the plurality of first grooves 364a opens toward the recording head 390 and does not have the through hole 365b. On the other hand, FIG. 5B is a cross-sectional view in which the second region A2 of the guide member 361 is enlarged. In the second region A2, a plurality of second grooves 364b are formed in the upper wall 364, and a through hole 365b provided corresponding to each of the plurality of second grooves 364b is formed in the lower wall 365. The through hole 365b penetrates the lower wall 365 along the thickness direction of the lower wall 365. The thickness direction is a direction along the Z axis.

[Material of first groove 364a]
With reference to Fig.5 (a), the material of the 1st groove | channel 364a provided in 1st area | region A1 of the guide member 361 is demonstrated. The first groove 364a provided in the first region A1 is preferably formed using a liquid-absorbing material (hereinafter referred to as “liquid-absorbing material”). For example, the liquid absorbing material is disposed at the bottom of the first groove 364a. Since the liquid absorbing material of the first groove 364a absorbs ink due to idle ejection or ejection mistake, ink collection performance can be improved. As a result, the occurrence of ink accumulation on the guide member 361 is suppressed, and the transportability of the recording medium P is stabilized.

  The liquid absorbing material is, for example, an elastic material having liquid absorbing properties. The elastic material having liquid absorption is, for example, a sponge or a nonwoven fabric. As the sponge, for example, Soflas N (trade name), which is a polyurethane sponge manufactured by Aion Co., Ltd., can be used. As the nonwoven fabric, for example, GS felt K10021M (trade name), which is a polyester / polyurethane nonwoven fabric manufactured by Toray Industries, Inc., can be used.

[Operation of Suction Unit 360]
The operation of the suction unit 360 will be described with reference to FIGS. 1 and 3. 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 362. The negative pressure acts on the recording medium P through the plurality of through holes 365b and the plurality of second grooves 364b of the guide member 361 and the plurality of suction holes (not shown) formed in 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.

[Function of the first area A1]
With reference to FIGS. 1-3, the function of 1st area | region A1 of the guide member 361 is demonstrated. In the first region A1 facing the recording head 390 (ink jet head 390k to ink jet head 390y), a first groove 364a in which the through hole 365b is not formed is formed. Accordingly, the air flow immediately below the recording head 390 is suppressed.

  The reason why the first area A1 is arranged facing the recording head 390 will be described. A plurality of grooves and a plurality of through holes are formed in the guide member of a general suction portion over the entire area. Accordingly, it is considered that a large amount of paper dust on the recording medium is conveyed to the image forming space from the upstream side in the recording medium conveyance direction rather than the image forming space by the air flow through the plurality of grooves and the plurality of through holes. It is done. The image forming space is a space between the recording head and the guide member.

  In a general suction section, a plurality of grooves and a plurality of through holes are also arranged in a region of the guide member that faces the recording head, so that the paper dust is moved to the vicinity of the recording head by the flow of air immediately below the recording head. It is thought that there is a possibility that the nozzles of the recording head will eventually be blocked. Therefore, a defect may occur in the image formed on the recording medium.

  Therefore, in the first embodiment, the first region A1 is disposed immediately below the recording head 390, and the air flow immediately below the recording head 390 is suppressed, whereby paper dust is drawn directly below the recording head 390. To suppress that. 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.

  The first region A1 is provided with a first groove 364a, and the second region A2 is provided with a second groove 364b. Therefore, the contact area between the conveyance belt 355 and the guide member 361 is reduced. As a result, it is possible to reduce the driving load of the conveyor belt 355 while suppressing the air flow directly under the recording head 390.

  Furthermore, the guide member 361 has the first area A1, and the air displacement immediately below the recording head 390 can be suppressed, so that the positional shift and color shift of the image can be suppressed. Details will be described below.

  Generally, the configuration of the guide member 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 guide member that affects the flow of air immediately below the recording head is considered to be one factor that determines the accuracy of ink flight, and thus the positional deviation and color deviation of the image.

  Therefore, in the first embodiment, the guide member 361 has the first region A1, and the air flying accuracy is suppressed by suppressing the air flow directly under the recording head 390. As a result, it is possible to suppress image positional deviation and color deviation.

[Relationship between the number of non-ejection nozzles and the number of output media P]
With reference to FIG. 6, the relationship between the number of non-ejection nozzles and the number of output sheets of the recording medium P will be described. FIG. 6 is a graph showing the relationship between the number of non-ejection nozzles and the number of output sheets of the recording medium P in the comparative example and the example. In the transport device according to the comparative example, a plurality of first grooves 364a and a plurality of through holes 365b are also formed in the first region A1 of the guide member 361 facing the recording head 390. In the transport apparatus according to the embodiment, the transport apparatus 300 is applied.

  In FIG. 6, the vertical axis represents the number of non-ejection nozzles. The number of non-ejection nozzles is the number of nozzles that cause nozzle clogging. The horizontal axis represents the number of output sheets (× 1000) of the recording medium P. A broken line N1 indicates a transition of the number of non-ejection nozzles with respect to the number of output of the recording medium P on which an image is formed by the ink jet recording apparatus 1 on which the transport apparatus 300 is mounted. A broken line N2 indicates a transition of the number of non-ejection nozzles with respect to the number of output sheets of the recording medium P on which an image is formed by the ink jet recording apparatus equipped with the transport apparatus according to the comparative example.

  In the inkjet recording apparatus 1 according to the first embodiment, the number of non-ejection nozzles is 10 or less and is substantially constant without depending on the increase in the number of output sheets. On the other hand, in the ink jet recording apparatus according to the comparative example, the number of non-ejection nozzles increases to 10 or more as the number of output sheets increases, and the number of non-ejection nozzles and the number of output sheets are approximately proportional. In the inkjet recording apparatus 1 according to the first embodiment, it was confirmed that the number of non-ejection nozzles per output sheet number when forming an image on the recording medium P was smaller than that in the comparative example.

[First Modification and Second Modification of Guide Member 361]
A first modified example and a second modified example of the guide member 361 will be described with reference to FIGS. As described with reference to FIGS. 2 and 4, in the first embodiment, one first region A1 faces all of the plurality of nozzles B of one inkjet head 390k. The same applies to the inkjet heads 390c to 390y. However, in the first modification and the second modification, the first area A1 faces a part of the plurality of nozzles B of one inkjet head 390k, and the second area A2 is the other of the plurality of nozzles B. Opposite the part. The same applies to the inkjet heads 390c to 390y.

  FIG. 7A shows a first modification of the guide member 361 of the transport apparatus 300. The recording head 390 includes a plurality of inkjet heads 390k that eject ink of the same color. Of the plurality of ink jet heads 390k, the end Q of one ink jet head 390k and the part R of the other ink jet head 390k are arranged along the transport direction D of the recording medium P. The end Q of one inkjet head 390k faces the second region A2. A part R of the other inkjet head 390k faces the first region A1.

  Since the end Q includes a part J1 of the nozzle formation region 391 (a region indicated by a right-upward oblique line), the second region A2 faces the part J1 of the nozzle formation region 391. On the other hand, the first region A1 faces another part of the nozzle formation region 391 and the other nozzle formation region 391.

  In the first modified example, since the end Q of the inkjet head 390k faces the second region A2, the second region A2 is wider compared to the first embodiment described with reference to FIG. Accordingly, the area where the recording medium P is attracted is widened, the adhesion between the recording medium P and the transport belt 355 can be improved, and the recording medium P can be transported stably.

  Here, as shown in FIG. 4 and FIG. 7A, the ejection of ink from the nozzles B included in the part J1 of the nozzle formation region 391 may not be executed. That is, the nozzle B included in the part J1 of the nozzle formation region 391 may be unused. Since the part J1 of the nozzle formation area 391 is adjacent to the part J2 (area shown by a slanting line on the lower right) of the nozzle formation area 391 in the part R of the inkjet head 390k along the transport direction D, the nozzle formation area 391 This is because the function of the part J1 can be replaced with the function of the part J2 of the nozzle formation region 391.

  When the nozzle B included in the part J1 of the nozzle formation region 391 is not used, the nozzle included in the part J1 of the nozzle formation region 391 due to the airflow by the through hole 365b facing the part J1 of the nozzle formation region 391. Even if paper dust adheres to B, it does not affect image formation on the recording medium P.

  In the first modification, the second area A2 facing the end Q of one inkjet head 390k is upstream of the first area A1 facing the part R of the other inkjet head 390k in the transport direction D. Be placed. Since the recording medium P is sucked through the through hole 365b of the second region A2 facing the end Q, the inkjet head 390k having a part R disposed downstream from the inkjet head 390k having the end Q. It is possible to reduce the possibility that the recording medium P hits the recording medium.

  Note that the first region A1 and the second region A2 are defined for the inkjet head 390c to the inkjet head 390y as well as the first region A1 and the second region A2 for the inkjet head 390k.

  FIG. 7B shows a second modification of the guide member 361 of the transport apparatus 300. Of the plurality of inkjet heads 390k that discharge ink of the same color, the end Q of one inkjet head 390k and the part R of the other inkjet head 390k are adjacent to each other in the transport direction D of the recording medium P. The end Q of one inkjet head 390k faces the second region A2. A part R of the other inkjet head 390k faces the first region A1.

  Further, a part S of one inkjet head 390k and an end T of another inkjet head 390k are adjacent to each other along the transport direction D of the recording medium P. A part S of one inkjet head 390k faces the first region A1. The end T of the other inkjet head 390k faces the second region A2.

  Since the end Q includes a part j1 of the nozzle formation region 391 (a region indicated by a diagonal line rising to the right), the second region A2 faces the part j1 of the nozzle formation region 391. On the other hand, the first region A1 faces another part of the nozzle formation region 391 and the other nozzle formation region 391.

  Since the end T includes a part j3 of the nozzle formation region 391 (a region indicated by an oblique line rising to the right), the second region A2 faces the part j3 of the nozzle formation region 391. On the other hand, the first region A1 faces another part of the nozzle formation region 391 and the other nozzle formation region 391.

  In the second modification, since the end Q of the inkjet head 390k and the end T of the inkjet head 390k are opposed to the second region A2, compared to the first embodiment described with reference to FIG. The two areas A2 are wide. Accordingly, the area where the recording medium P is attracted is widened, the adhesion between the recording medium P and the transport belt 355 can be improved, and the recording medium P can be transported stably.

  Here, as shown in FIG. 4 and FIG. 7B, the ink ejection from the nozzles B included in the part j1 of the nozzle formation region 391 and the part j3 of the nozzle formation region 391 may not be executed. . That is, the nozzles B included in the part j1 and the part j3 may not be used. The part j1 is adjacent to the part j2 of the nozzle formation area 391 in the part R of the inkjet head 390k (the area indicated by the slanting line at the lower right) along the transport direction D. This is because part j2 of the nozzle formation region 391 can be substituted. In addition, since part j3 is adjacent to part j4 (area shown by a slanting line at the lower right) of the nozzle formation area 391 in the part S of the inkjet head 390k along the transport direction D, part of the nozzle formation area 391 This is because j3 can be substituted by a part j4 of the nozzle formation region 391.

  When the nozzles B formed in the part j1 and the part j3 are not used, the nozzles formed in the part j1 and the part j3 due to the airflow by the through holes 365b facing the part j1 and the part j3. Even if paper dust adheres to B, it does not affect image formation on the recording medium P.

  In the second modification, the functions of the triangular part j1 and part j3 are replaced by the rectangular part j2 and part j4, so that ink can be ejected onto the recording medium P more appropriately. Note that the first area A1 and the second area A2 are defined for the inkjet head 390c to the inkjet head 390y as well as the first area A1 and the second area A2 for the inkjet head 390k.

  As described above with reference to FIGS. 1 to 7, according to the first embodiment, the first modified example, and the second modified example, the through hole is formed in the first region A <b> 1 that directly faces the recording head 390. By disposing the first groove 364a where the 365b is not formed, the air flow is suppressed directly below the recording head 390. Therefore, the paper dust rising immediately below the recording head 390 is suppressed, and adhesion of the paper dust to the recording head 390 is suppressed. As a result, clogging of paper dust into the nozzles B of the recording head 390 can be suppressed, and occurrence of defects in the image formed on the recording medium P can be suppressed.

(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 guide member 361 of the transport 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. The transport apparatus 300 according to the second embodiment includes a guide member 361 shown in FIGS. 8 and 9 instead of the guide member 361 of the transport apparatus 300 according to the first embodiment.

  FIG. 8 shows an outline of the guide member 361 of the transport apparatus 300 according to the second embodiment. In addition to the plurality of first regions A1 and the plurality of second regions A2, the guide member 361 contacts a feeding member (hereinafter referred to as “feeding member F” (see FIG. 1)) of the recording medium P. It has a plurality of third regions A3 through which the part passes. The plurality of third regions A3 are arranged along the transport direction D.

  FIG. 9 shows details of the guide member 361 of the transport apparatus 300 according to the second embodiment. A plurality of first grooves 364a are provided in each of the plurality of third regions A3. Accordingly, the through hole 365b is not formed in each of the plurality of third regions A3. As a result, the circulation of air above the third region A3 is suppressed, and the rise of paper dust above the third region A3 is suppressed. In FIG. 9, the reference sign “A2” of the second region A2 adjacent to the third region A3 is omitted for simplification of the drawing.

  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 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 conveyance direction D of the recording medium P.

  The third area A3 is an area through which a portion of the recording medium P in contact with the feeding member F passes in the guide member 361. 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 guide member 361 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 guide member 361 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 relatively small. 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 having a relatively small width.

  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.

  As described above, according to the second embodiment, in addition to the first area A1, the guide member 361 has the third area A3 arranged corresponding to the portion of the recording medium P where paper dust is likely to be generated. And the through-hole 365b is not formed in the 1st groove | channel 364a of 1st area | region A1 and 3rd area | region A3. Accordingly, air circulation 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 is likely to be generated passes. As a result, adhesion of paper dust to the recording head 390 is further suppressed, and clogging of paper dust to the nozzle B can be further suppressed. Further, by having the second region A2 having the through hole 365b, a sufficient suction force when sucking the recording medium P is secured. Furthermore, as shown in FIG. 8, the plurality of first regions A1 are arranged in a staggered pattern. Therefore, it is suitable for the inkjet heads 390k to 390y arranged in a staggered pattern.

  The embodiment of the present invention has been described above with reference to the drawings (FIGS. 1 to 9). 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 (7) 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 8, the guide member 361 has the first region A <b> 1 facing all of the one set of inkjet heads 390 k to 390 y. However, the guide member 361 may have the first region A1 facing one set, two sets, or three sets of inkjet heads among the one set of inkjet heads 390k to 390y.

  (2) As described with reference to FIGS. 2 and 8, the guide member 361 has three first regions A1 corresponding to the three inkjet heads 390k. However, the guide member 361 may have one or two first regions A1k facing one or two of the three inkjet heads 390k. The same applies to the first region A1 facing the other inkjet heads 390c to 390y.

  (3) As described with reference to FIGS. 2 and 8, the guide member 361 has one first region A <b> 1 that faces all of the plurality of nozzle formation regions 391 of one inkjet head 390 k. . However, the guide member 361 may have one or a plurality of first regions A1 facing a part of the plurality of nozzle formation regions 391 of one inkjet head 390k. The same applies to the first region A1 facing the other inkjet heads 390c to 390y.

  (4) As described with reference to FIG. 8, the third area A <b> 3 is an entire area in the guide member 361 through which the portion of the recording medium P that contacts the feeding member F passes. However, the third region A3 may be a part of the guide member 361 through which a portion of the recording medium P that contacts the feeding member F passes.

  (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. 4, 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 389y.

  (7) The first modified example and the second modified example described with reference to FIGS. 7A and 7B are the same as the transfer device 300 according to the second embodiment described with reference to FIGS. It can also be applied to the guide member 361.

  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 unit includes a guide member that supports the recording medium via the transport belt,
The guide member is formed with at least one first groove having no through hole and a second groove having a through hole,
The guide member has a first region facing the recording head, and a second region adjacent to the first region,
In the first region, the at least one first groove is provided,
The transfer device, wherein the second groove is provided in the second region. 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 guide member further includes a third region through which a portion of the recording medium in contact with the feeding member passes,
The at least one first groove is plural,
The transport apparatus according to claim 1, wherein the first groove is provided in the third region. The recording head includes a plurality of inkjet heads that eject ink of the same color,
An end portion of one of the plurality of inkjet heads and a part of the other inkjet head are adjacent to each other along a conveyance direction of the recording medium,
The end of the one inkjet head faces the second region,
The transport apparatus according to claim 1, wherein the part of the other inkjet head is opposed to the first region.   The said 2nd area | region facing the said edge part of the said one inkjet head is arrange | positioned in the upstream of the said conveyance direction rather than the said 1st area | region facing the said one part of the said other inkjet head. The conveying apparatus as described.   The conveying device according to any one of claims 1 to 4, wherein the first groove is formed using a material having liquid absorbency. A plurality of the first regions are provided,
The transfer device according to any one of claims 1 to 5, wherein the plurality of first regions are arranged in a staggered pattern. 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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