JP2006051720A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an inkjet recorder which can perform image recording by multipass in a simple and compact structure. <P>SOLUTION: A guide member 26 has an arc-shaped guide part 26G with a predetermined radius of curvature R2. The guide part 26G is disposed to project towards the outside seen from a driving roller 24. The relation of L<R1+R2 is satisfied for a pitch L between centers of the driving roller 24 and the guide part 26G, a radius R1 of the driving roller 24 and the radius of curvature R2 of the guide part 26G. The pitch L between the centers can be made small even when the radius R1 of the driving roller 24 and the radius of curvature R2 of the guide part 26G are made large, so that the inkjet recorder 12 can be made compact as a whole. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus compatible with so-called multi-pass that allows a recording medium to pass through an ink droplet ejection region from an ink jet recording head a plurality of times.

  Some ink jet recording apparatuses perform image recording by ejecting ink droplets from an ink jet recording head onto a held recording medium while rotating the recording medium while being held on a drum or the like. By rotating the recording medium in this way, so-called multi-pass is also possible in which the recording medium passes through the ink droplet ejection area from the inkjet recording head a plurality of times.

  For example, Patent Document 1 describes an ink jet printer in which a print medium is held on the outer peripheral surface of a drum and ink is sprayed onto the print medium from each color nozzle unit.

  However, when the print medium is held on a drum having a cylindrical outer peripheral surface as in Patent Document 1, it is necessary to also arrange the nozzle unit obliquely according to this, for example, positioning and maintenance of the nozzle unit, ink, Control and configuration of supply and the like become complicated. Even if the nozzle units are arranged obliquely, it is practically impossible or extremely difficult to make the distance between the nozzle surface and the outer peripheral surface of the drum (print medium) constant. In particular, when the nozzles are two-dimensionally arranged in one nozzle unit, the nozzles exist at different positions in the circumferential direction (rotation direction) of the drum, so the distance between these nozzles and the print medium is set as follows. It is difficult to make it constant. Here, for example, it may be possible to reduce the difference in distance from the print medium for each nozzle by increasing the drum, but the increase in the size of the drum also increases the size of the inkjet printer.

  In Patent Document 2, an electrostatic adsorption belt is supported by two shafts, and a print head can be opposed to a flat portion of the electrostatic adsorption belt so that paper can pass through the print head as many times as possible. A printing press is described.

However, in the configuration of Patent Document 2, since the sheet is curved in the thickness direction at the portion where the electrostatic attraction belt is wound around the shaft, the sheet may be peeled off from the electrostatic attraction belt when the diameter of the shaft is small. If the diameter of the shaft is increased to prevent this, the size of the printing press will be increased.
Japanese Patent Laid-Open No. 10-138516 JP 10-166563 A

  In view of the above-described facts, an object of the present invention is to obtain an ink jet recording apparatus capable of multi-pass image recording with a simple and compact structure.

According to the first aspect of the present invention, the conveying belt is formed in an endless shape and can circulate while holding the recording medium on the outer peripheral surface, and the circulation driving force is arranged in contact with the conveying belt on the inner side of the conveying belt. A driving roller that acts on the inner side of the conveying belt, a guide unit that is disposed in contact with the conveying belt inside the conveying belt and guides the conveying belt to bend with a curvature of a predetermined value or less, the driving roller, and the guiding An ink jet recording head that is disposed opposite to a flat portion of the conveyor belt that is configured between the recording belt and the recording medium on the flat portion to eject ink droplets according to image information, and the center of the drive roller. And the center-to-center curvature L of the guide portion with respect to the radius R1 of the driving roller and the curvature radius R2 of the guide portion,
L <R1 + R2
The drive roller and the guide means are arranged so as to satisfy the above.

  Therefore, the recording belt is circulated in a state where the recording medium is held on the outer peripheral surface of the conveying belt, so that the recording medium is passed through the ejection area of the inkjet recording head (area where ink droplets are ejected) multiple times, so-called multipass Can record images. Since the inkjet recording head is disposed opposite to the flat portion of the conveyance belt formed between the drive roller and the guide portion, for example, it is arranged side by side along the circulation direction of the conveyance belt (the conveyance direction of the recording medium). As in the prior art, it is not necessary to dispose the inkjet recording head obliquely in correspondence with the cylindrical drum. For this reason, a structure becomes simple compared with the structure arrange | positioned diagonally.

The drive roller and the guide means are such that the center-to-center pitch L between the center of the drive roller and the center of curvature of the guide portion is L <R1 + R2 with respect to the radius R1 of the drive roller and the radius of curvature R2 of the guide portion.
It is arranged to satisfy. That is, for example, in comparison with a configuration in which a roller having a radius R2 is used instead of the guide means, the drive roller and the guide means are arranged close to each other. As a result, the entire inkjet recording apparatus can be reduced in size.

  Note that at least one drive roller and one guide portion need to be provided, but two or more each may be provided. In this case, the flat portion according to the present invention includes not only a portion between the driving roller and the guide portion but also a portion formed between two adjacent driving rollers or between the two guide portions. For example, when the number of guide portions is two for one drive roller, a flat portion formed between the two guide portions is also included in the flat portion according to the present invention. The two guide portions may be provided in one guide means, or two guide means provided with one guide portion may be arranged.

  According to a second aspect of the present invention, in the first aspect of the present invention, the flat portion of the conveying belt formed between the driving roller and the guide portion is supported from the inside of the conveying belt. The supporting member to be arranged is arranged.

  Therefore, since the support member supports the portion of the conveyor belt located between the driving roller and the guide portion from the inside, the local depression of the conveyor belt is reduced, and flatness can be ensured more reliably.

  According to a third aspect of the present invention, in the second aspect of the present invention, the support member is integrated with the guide means.

  This reduces the number of parts. Further, it is not necessary to align the support member with the guide portion.

  In the invention according to claim 4, in the invention according to any one of claims 1 to 3, one or a plurality of driven rollers that are driven and rotated by the guide means in contact with the conveyor belt from the inside, Is provided.

  Since the driven roller is driven to rotate as the conveyor belt circulates, the load (resistance) acting on the circulation of the conveyor belt is reduced, and the conveyor belt can be circulated smoothly.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the ink jet recording head includes the conveyance belt configured between the driving roller and the driven roller. The plurality of flat portions are provided so as to face each of at least two flat portions.

  Therefore, even when the ink jet recording head is long in the recording medium conveyance direction, the ink jet recording head can be divided and disposed at locations facing the plurality of flat portions. For example, four inkjet recording heads can be divided into two, and can be made to face two flat portions. Further, it is possible to record a high-quality image by arranging more inkjet recording heads as compared with the configuration in which the inkjet recording heads are arranged facing only one flat portion.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects of the present invention, the ink jet recording head has a width direction perpendicular to the recording medium conveyance direction with respect to the entire width of the recording medium. And having a width capable of ejecting ink droplets.

  Since there is no need to move the ink jet recording head in a direction perpendicular to the recording medium conveyance direction, a mechanism for movement is not required, the ink jet recording apparatus can be miniaturized, and image recording speed is increased. It becomes possible to do. Of course, the inkjet recording head is moved in a direction perpendicular to the moving direction of the recording medium, and the effect of multi-pass image recording (obtaining a high-resolution image with high resolution, or using the inkjet recording head as a result of recording) Etc.) may be obtained. Even in this case, it is not necessary to move the ink jet recording head over the entire width of the recording medium. Therefore, the moving mechanism can be reduced in size, and the ink jet recording apparatus can also be reduced in size.

  Since the present invention has the above-described configuration, multipass image recording can be performed with a simple and compact structure.

  FIG. 1 shows an ink jet recording apparatus 12 according to a first embodiment of the present invention. A paper feed tray 16 is provided in the lower part of the casing 14 of the ink jet recording apparatus 12, and the sheets P stacked in the paper feed tray 16 can be taken out one by one by a pickup roller 18. The taken paper P is transported by a plurality of transport roller pairs 20 constituting a predetermined transport path 22. Hereinafter, the “conveying direction” simply refers to the conveying direction of the paper P that is a recording medium, and the “upstream” and “downstream” refer to upstream and downstream in the conveying direction, respectively.

  Above the paper feed tray 16, an endless transport belt 28 stretched between the drive roller 24 and the guide member 26 is disposed, and the transport belt 28 has two flat portions 28 </ b> F at the top and bottom. . A recording head array 30 is disposed above the conveyor belt 28 and faces the flat portion 28F (see FIG. 3) on the upper side of the conveyor belt 28. This opposed area is an ejection area SE where ink droplets are ejected from the recording head array 30. The sheet P transported along the transport path 22 is held by the transport belt 28 and reaches the discharge area SE, and ink droplets corresponding to image information are attached from the recording head array 30 in a state of facing the recording head array 30. The

  Then, by rotating the paper P while being held by the transport belt 28, the paper P can be passed through the discharge region SE a plurality of times, and so-called multipass image recording can be performed. Therefore, the surface of the conveyance belt 28 is a circulation path of the paper P in the present invention.

  The conveyor belt 28 is made of a polymer material that can cause charges to remain on the surface by charging, for example, polyimide or polyester.

  As shown in FIG. 3, the recording head array 30 has a long shape in which the effective recording area in the present embodiment is equal to or larger than the width of the paper P (the length in the direction orthogonal to the transport direction), and yellow (Y ), Magenta (M), cyan (S), and black (K), four inkjet recording heads 32 corresponding to each of the four colors are provided. Each of these inkjet recording heads 32 is arranged in the direction in which the longitudinal direction thereof coincides with the width direction of the paper P and the transport direction and along the transport direction, so that a full-color image can be recorded. The method for ejecting ink droplets in each inkjet recording head 32 is not particularly limited, and a known method such as a so-called thermal method or piezoelectric method can be applied. The plurality of ink jet recording heads 32 may be integrated to form the recording head array 30.

  Each inkjet recording head 32 is controlled by recording head control means (not shown). For example, the recording head control means determines the ink droplet ejection timing and the ink ejection port (nozzle) to be used according to the image information, and sends a drive signal to the inkjet recording head 32. Further, the overall operation of the inkjet recording apparatus 12 is controlled by system control means (not shown).

  In addition, the recording head array 30 may be fixed in a direction orthogonal to the transport direction, which eliminates the need for a mechanism for moving the recording head array 30 (each inkjet recording head 32). The entire recording apparatus 12 can be reduced in size. If the recording head array 30 is configured to move slightly in the direction orthogonal to the transport direction as necessary, an image with higher resolution can be recorded in the paper width direction by multi-pass image recording. In addition, it is possible to prevent defects (image unevenness, white stripes, etc.) of the ink jet recording head 32 from being reflected in the recording result. Even with this configuration, the moving distance of the recording head array 30 is small, and it is not necessary to move the recording head array 30 over the entire width thereof. For this reason, the mechanism for movement can be simplified and the entire inkjet recording apparatus 12 can be reduced in size. In addition, although a cam etc. can be used as a structure which moves the recording head array 30 (inkjet recording head 32) slightly in the width direction in this way, for example, it is not limited to this.

  As shown in FIGS. 1 and 2, four maintenance units 34 corresponding to the respective ink jet recording heads 32 are arranged in the vicinity of the recording head array 30. Each of the maintenance units 34 wipes, as necessary, a dummy jet receiving member that receives ink droplets jetted from the ink jet recording head 32, a capping member that caps the nozzle surface 32N (see FIG. 3), and the nozzle surface 32N. A wiping member is provided. When maintenance is performed on the inkjet recording head 32, the recording head array 30 moves upward as shown in FIG. 2, and the maintenance unit 34 moves to a gap formed between the conveyance belt 28 and the maintenance unit 34. Get in. Then, a predetermined maintenance operation (vacuum, dummy jet, wiping, capping, etc.) is performed while facing the nozzle surface 32N.

  As shown in detail in FIGS. 3 and 4, a suction / charging roller 36 to which a power source (not shown) is connected is disposed upstream of the recording head array 30. The suction / charging roller 36 is driven between the driving roller 24 while sandwiching the conveyance belt 28 and the paper P, and presses the paper P against the conveyance belt 28, and a separation position separated from the conveyance belt 28. It can be moved. At the pressing position, the conveyed paper P can be guided to the transport belt 28. At this time, a predetermined potential difference is generated between the driving roller 24 and the sheet P, so that electric charges can be applied to the conveying belt 28.

As the suction / charging roller 36, for example, a roller having a diameter of 14 mm in which conductive rubber is coated on the surface of silicone rubber and the volume resistance value is adjusted to about 10 ⁶ to 10 ⁷ Ω · cm can be used.

  The power source may be a DC power source or an AC power source as long as the paper P can be charged to a predetermined potential.

  A registration roller (not shown) is provided further upstream than the suction / charging roller 36 and is positioned before the paper P reaches between the conveyance belt 28 and the suction / charging roller 36.

  On the downstream side of the recording head array 30, a plurality of peeling claws 56 that are rotatably held by a shaft member 58 are arranged at a certain interval in the width direction of the paper P. The peeling claw 56 is configured to rotate between a peeling position where the tip of the peeling claw 56 comes into contact with the conveyance belt 28 and separates the paper P from the conveyance belt 28 and a separation position separated from the conveyance belt 28. At the separated position, the paper P is not peeled off from the conveyor belt 28, so that multi-pass image recording is possible.

  Further, a static eliminator 60 is disposed between the recording head array 30 and the peeling claw 56 to assist in the removal of the transport belt 28 and the paper P so that the peeling by the peeling claw 56 can be easily performed.

  The peeled paper P is transported by a plurality of discharge roller pairs 42 that constitute a discharge path 44 on the downstream side of the peeling plate 40, and is discharged to a paper discharge tray 46 provided on the top of the housing 14.

  A reversing path 52 composed of a plurality of reversing roller pairs 50 is provided between the paper feed tray 16 and the conveying belt 28, and the sheet P on which an image is recorded on one side is reversed and held on the conveying belt 28. By doing so, it is possible to easily record images on both sides of the paper P.

  Between the conveyance belt 28 and the paper discharge tray 46, an ink tank 54 for storing each of the four color inks is provided. The ink in the ink tank 54 is supplied to the recording head array 30 through an ink supply pipe (not shown). As the ink, various known inks such as water-based ink, oil-based ink, and solvent-based ink can be used.

  As shown also in FIGS. 5 and 6, the drive roller 24 includes a shaft 62 disposed along the width direction, and a cylindrical roller body 64 fixed to the shaft 62. The roller body 64 is configured by covering the surface of a hard member such as metal with rubber. The roller body 64 has a predetermined radius R1, and the outer peripheral surface of the roller body 64 contacts and supports the conveyor belt 28 from the inside.

  On the other hand, the guide member 26 has an arcuate (substantially semi-cylindrical) guide portion 26G having a predetermined radius of curvature R2. The guide member 26 is disposed so that the guide portion 26G is convex outward (right side in FIG. 4) when viewed from the drive roller 24, and is in contact with the conveyor belt 28 from the inside to apply tension. Thereby, the conveyor belt 28 is stably stretched and supported. Accordingly, the conveyor belt 28 that receives the driving force from the driving roller 24 circulates while sliding with respect to the guide portion 26G.

Here, the drive roller 24 and the guide member 26 are arranged so that the drive roller 24 enters a virtual circle C2 having a radius R2 assumed along the guide portion 26G. In other words, in this embodiment, the conveying belt 28 is supported by the guide member 26 having the arcuate guide portion 26G, so that the drive roller 24 substantially enters the inside of the guide portion 26G. Are placed close together. Accordingly, assuming a roller having a radius R2 (which coincides with the radius of curvature of the guide portion 26G) instead of the guide portion 26G, the roller and the driving roller 24 partially overlap when viewed in the axial direction. . That is, if the center-center pitch of the center of curvature of the virtual circle C2 of the drive roller 24 and the guide member 26 is L,
L <R1 + R2
The relationship is satisfied.

  In general, in an ink jet recording apparatus that enables so-called multi-pass, it is necessary to rotate the paper P a plurality of times in a state where the paper P is attracted to the transport belt or the like. From this point of view, it is preferable to increase the radius of curvature of the member on which the conveyor belt is stretched. However, for example, when a large-diameter roller or a member having a large curvature radius is used, the overall size of the ink jet recording apparatus is increased.

  On the other hand, in the present embodiment, the driving roller 24 and the guide member 26 that stretch and support the transport belt 28 are brought close to each other by adopting the above configuration. That is, even if the radius R1 of the driving roller 24 and the radius of curvature R2 of the guide portion 26G are increased, the center-to-center pitch L can be decreased. As a result, the entire inkjet recording apparatus 12 can be reduced in size.

  Note that the center-to-center pitch L, the radius R1 of the driving roller 24, and the radius of curvature R2 of the guide portion 26G are not particularly limited as long as these conditions are satisfied, but in this embodiment, for example, L = 100 mm, R1 = 80 mm, R2 = 80 mm It is said.

  As shown in FIGS. 3 to 5, the guide member 26 further includes a flat plate-like support plate 26 </ b> S extending from the top and bottom of the guide portion 26 </ b> G. The support plate 26S is supported by contacting the conveyor belt 28 from the inside between the driving roller 24 and the guide portion 26G. Thereby, the dent of the conveyance belt 28 is prevented, and the flatness of the flat portion 28F can be kept high between the driving roller 24 and the guide portion 26G, and the paper P can be conveyed stably. In addition, a change in the interval between the inkjet recording head 32 and the paper P during image recording is suppressed, and a higher quality image can be recorded.

  The support plate 26S may be a separate support member from the guide portion 26G. However, as described above, if the support plate 26S is integrated with the guide member 26 by extending from the guide portion 26G, the number of parts is reduced. Less. Moreover, it is not necessary to align and attach the guide member to the guide portion 26G, which is preferable.

  The guide member 26 can be made of a metal material (such as stainless steel) that can be molded by a press or the like, or a resin material such as plastic. As described above, since the conveyor belt 28 slides, it is preferable that the surface is not easily worn, the sliding resistance with the conveyor belt 28 is low, and the conveyor belt 28 is not damaged.

  In the ink jet recording apparatus 12 of the present embodiment configured as described above, the paper P taken out from the paper feed tray 16 is transported to the transport belt 28 as described above. Then, the suction and charging roller 36 guides and presses against the conveyance belt 28, and the suction and charging roller 36 attracts and holds the conveyance belt 28 by an applied voltage. In this state, the paper P passes through the ejection area SE by circulation of the conveyance belt 28, and ink droplets are ejected from the recording head array 30, and an image is recorded on the paper P. When recording an image in only one pass, the sheet P and the conveyance belt 28 are neutralized by the static eliminator 60, and then the sheet P is separated from the conveyance belt 28 by the separation claw 56, and is conveyed by the discharge roller pair 42 and discharged. The paper is discharged to the paper tray 46.

  On the other hand, when image recording is performed by multi-pass, the neutralization by the static eliminator 60 is not performed, and the separation claw 56 is also set at the separation position so that the sheet P is circulated until the required number of times is reached and passed through the ejection region SE. . After this reaches a predetermined number of times, the sheet P and the conveyor belt 28 are neutralized by the static eliminator 60, and then the sheet P is separated from the conveyor belt 28 by the peeling claw 56, and is conveyed by the discharge roller pair 42 and discharged. To discharge. Note that the actual number of passes in the case of multi-pass is not particularly limited, and can be determined according to, for example, a desired resolution of a recorded image.

  In the inkjet recording apparatus 12 of the present embodiment, the conveying belt 28 is stretched and supported by the driving roller 24 and the guide member 26, thereby forming a flat portion 28 </ b> F on the conveying belt 28 and facing the flat portion 28 </ b> F. In addition, the inkjet recording heads 32 are arranged side by side in the transport direction of the paper P. In a configuration using a cylindrical or columnar conveying member as in the prior art, the inkjet recording head needs to be disposed obliquely. In the present embodiment, the inkjet recording head 32 is disposed side by side along the flat portion 28F. Since it can, it becomes a simple structure.

  Further, in the ink jet recording apparatus 12, as described above, the drive roller 24 and the guide member 26 are brought close to each other and the center-to-center pitch L is reduced, so that the ink jet recording apparatus 12 is also downsized. . In particular, in a configuration for performing multi-pass image recording, it is preferable to use a large-diameter drive roller 24 and guide portion 26G because the paper P is rotated a plurality of times while being sucked and held by the conveyor belt 28. In the present embodiment, since it is possible to use a large-diameter drive roller 24 and guide portion 26G without causing an increase in the size of the entire inkjet recording apparatus 12, the paper P is not prepared from the conveyance belt 28. It is also possible to more surely prevent peeling and peeling.

  Further, since the entire length of the transport belt 28 is also shortened, the time for rotating the paper P is shortened, and the time required for image recording (particularly, the time for recording an image on the first paper P (FPOT)) is reduced. Can be shortened.

  As in the modification shown in FIG. 6, an auxiliary roller 68 that contacts the conveyor belt 28 from the inside may be provided as necessary. Examples of the auxiliary roller 68 include a tension roller that adjusts the tension by pressing the conveyance belt 28 from the inside. Further, since it is sufficient for the auxiliary roller 68 to perform the above-described operation, if the roller roller having a smaller diameter than the driving roller 24 and the guide portion 26G is used, the auxiliary roller 68 causes the ink jet recording apparatus 12 to function. There will be no increase in size. Even if the small-diameter auxiliary roller 68 is used, if the wrap angle θ at the contact portion of the transport belt 28 (the central angle with the contact portion of the transport belt 28 being an arc) is sufficiently small, the sheet from the transport belt 28 P can be prevented from lifting and peeling.

  FIG. 7 shows the vicinity of the drive roller 24 and the guide member 26 of the ink jet recording apparatus according to the second embodiment of the present invention.

  In the second embodiment, the drive roller 24 and the guide member 26 are arranged so as to be up and down (in FIG. 10, the drive roller 24 is down and the guide member 26 is up, but the reverse is also possible), and between them A recording head array 31 composed of two ink jet recording heads 32 is opposed to each of two flat portions 28F of the conveyor belt 28 that is configured. In one inkjet recording head 32, the length L1 along the transport direction is long, and a predetermined number (for example, four as in the first embodiment) of inkjet recording heads 32 may be arranged side by side on one flat portion 28F. Even when it is difficult or impossible, a predetermined number of ink jet recording heads 32 can be disposed by dividing the ink jet recording heads 32 into two flat portions 28F.

  Further, even when a predetermined number of ink jet recording heads 32 can be disposed opposite to one flat portion 28F, ink jet recording can be performed by further disposing the ink jet recording head 32 opposite to another flat portion 28F. It is also possible to increase the number of heads 32 so that a higher quality image can be recorded.

  In FIG. 7, the driving roller 24 and the guide member 26 are arranged up and down so that the flat portion 28F is in the vertical direction. Of course, as in the first embodiment (see FIG. 4), in the configuration in which two horizontal flat portions 28F are vertically positioned, the ink jet recording head 32 is opposed to the upper and lower flat portions 28F. May be arranged. However, in this configuration, the ejection direction of the ink droplets from the upper inkjet recording head 32 and the direction of gravity coincide with each other, but these are reversed in the lower inkjet recording head 32. It is necessary to adjust the discharge state so that the upper and lower ink jet recording heads 32 coincide with each other.

  On the other hand, as shown in FIG. 7, when the two flat portions 28 </ b> F are both configured to be in the vertical direction, the ink droplet ejection direction and the gravity direction in both of the two inkjet recording heads 32. Is the same (orthogonal), and the adjustment as described above is simplified and more preferable.

  FIG. 8 shows the drive roller 24 and the guide member 74 of the ink jet recording apparatus according to the third embodiment of the present invention. Similar to the guide member 26 of the first embodiment, the guide member 74 has an arcuate guide portion 74G and a flat plate-like support portion 74S. Further, the guide member 74 is disposed close to the drive roller 24 so that the entire inkjet recording apparatus can be reduced in size.

  Furthermore, in the third embodiment, as shown in FIG. 9, a plurality of (five in this embodiment) long holes 76 are formed in the guide member 74.

  Each of the long holes 76 has a direction in which the width direction becomes the longitudinal direction, and is formed at a constant interval in the transport direction.

  A small-diameter driven roller 78 is similarly disposed in each of the long holes 76 in a direction in which the width direction coincides with the longitudinal direction. As can be seen from FIG. 8, the small-diameter driven roller 78 is disposed so that a part of the outer peripheral surface thereof is flush with (or slightly protrudes from) the outer surface of the guide portion 26G. When 28 slides, it rotates (follows) by friction. As a result, the load on the circulation of the conveyor belt 28 can be further reduced, and the conveyor belt 28 can be smoothly circulated.

  In the third embodiment, the number of small-diameter driven rollers 78 is not limited and may be one. However, in order to realize smooth sliding of the conveyor belt 28, it is preferable to provide a plurality of belts, and it is more preferable to have about five (or more) as shown in FIGS.

  FIG. 10 shows the drive roller 24 and the small-diameter driven roller 80 of the ink jet recording apparatus according to the fourth embodiment of the present invention. In the fourth embodiment, the small-diameter driven roller 80 has substantially the same configuration and arrangement as the small-diameter driven roller 78 of the third embodiment. However, as shown in FIG. It is different in that it is not arranged.

  Even in the configuration in which the guide member 74 is omitted in this manner, as can be seen from FIG. 10, the conveyance belt 28 is substantially guided in a substantially arc shape as in the configuration including the guide member 26 or the guide member 74. ing. Therefore, the guide means of the present invention is constituted by the plurality of small-diameter driven rollers 80.

  Here, the radius R3 of each small-diameter driven roller 80 is smaller than the radius R2 of the guide portion 26G of the first embodiment, but the wrap angle α of the conveying belt 28 with respect to each small-diameter driven roller 80 is also small. For this reason, the sheet P does not float from the conveying belt 28 due to the small radius R3 of the small-diameter driven roller 80. The entirety of the plurality of small-diameter driven rollers 78 is guided in an arc shape having a radius of approximately R2, as in the case of being guided by the guide portion 26G of the first embodiment. Thereby, similarly to the first embodiment, the paper P can be reliably sucked and held by the transport belt 28.

It is the schematic which shows the inkjet recording device of 1st Embodiment of this invention in an image recording state. It is the schematic which shows the inkjet recording device of 1st Embodiment of this invention in a maintenance state. FIG. 2 is a schematic perspective view illustrating a conveyance belt and the vicinity thereof in the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 2 is a schematic front view showing a conveyance belt and its vicinity of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 2 is a perspective view illustrating a driving roller and a guide member of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 5 is a schematic front view showing a conveyance belt and its vicinity of an inkjet recording apparatus according to a modification of the first embodiment of the present invention. It is a schematic front view which shows the conveyance belt of the inkjet recording device of 2nd Embodiment of this invention, and its vicinity. It is a schematic front view which shows the conveyance belt of the inkjet recording device of 3rd Embodiment of this invention, and its vicinity. It is a perspective view which shows the drive roller of the inkjet recording device of 3rd Embodiment of this invention, a guide member, and a small diameter driven roller. It is a schematic front view which shows the conveyance belt and its vicinity of the inkjet recording device of 4th Embodiment of this invention. It is a perspective view which shows the drive roller and small diameter driven roller of the inkjet recording device of 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Inkjet recording device 14 Housing | casing 16 Paper feed tray 18 Pickup roller 20 Conveyance roller pair 22 Conveyance path 24 Drive roller 26 Guide member 26G Guide part 26S Support plate 28 Conveyor belt 28F Flat part 30 Recording head array 31 Recording head array 32 Inkjet recording Head 32N Nozzle surface 34 Maintenance unit 36 Suction / charging roller 40 Peeling plate 42 Ejection roller pair 44 Ejection path 46 Ejection tray 50 Reversing roller pair 52 Reversing path 54 Ink tank 56 Peeling claw 58 Shaft member 60 Charger 62 Shaft 64 Roller Main body 68 Auxiliary roller 74 Guide member 74G Guide section 74S Support section 76 Long hole 78 Small diameter driven roller 80 Small diameter driven roller C2 Virtual circle L Center pitch P Paper R1 Radius R2 Radius of curvature R3 Radius SE Discharge area α Lap angle θ Lap angle

Claims (6)

A transport belt formed endlessly and capable of circulating while holding a recording medium on the outer peripheral surface;
A driving roller that is disposed in contact with the conveyor belt inside the conveyor belt and applies a circulation driving force to the conveyor belt;
A guide means provided with a guide portion that is arranged in contact with the conveyor belt inside the conveyor belt and guides the conveyor belt to bend with a curvature of a predetermined value or less;
An ink jet recording head disposed opposite to a flat portion of the transport belt configured between the drive roller and the guide portion, and ejecting ink droplets according to image information onto a recording medium on the flat portion;
With
The center-to-center pitch L between the center of the drive roller and the center of curvature of the guide portion is set to the radius R1 of the drive roller and the radius of curvature R2 of the guide portion.
L <R1 + R2
An ink jet recording apparatus, characterized in that a drive roller and guide means are arranged so as to satisfy the above. A support member for supporting a flat portion of the conveyor belt formed between the driving roller and the guide portion from the inside of the conveyor belt;
The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is arranged.   The inkjet recording apparatus according to claim 2, wherein the support member is integrated with the guide unit. One or a plurality of driven rollers that are driven to rotate in contact with the conveyor belt from the inside,
The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is provided.   A plurality of the ink jet recording heads are provided so as to face each of at least two flat portions of the plurality of flat portions of the transport belt formed between the driving roller and the driven roller. The inkjet recording apparatus according to any one of claims 1 to 4.   6. The inkjet recording head according to claim 1, wherein the inkjet recording head has a width capable of ejecting ink droplets with respect to the entire width of the recording medium in a width direction orthogonal to the conveyance direction of the recording medium. 2. An ink jet recording apparatus according to item 1.

Images