JP4341614B2 - Recording medium conveying belt and ink jet recording apparatus provided with the same - Google Patents

Description

  The present invention relates to a recording medium conveyance bell that conveys a recording medium while holding the recording medium on a surface thereof, and an ink jet recording apparatus including the recording medium conveyance bell.

  In an ink jet recording apparatus, a recording medium such as paper or cloth is transported while being held on a transport belt. And in order to improve the conveyance accuracy by a conveyance belt, it conveys while fixing a recording medium to the adhesion layer formed on the conveyance belt (refer patent document 1) and a recording medium adsorb | sucking on a conveyance belt by electrostatic force (refer patent document 1). The technique (refer patent document 2) etc. to perform are known.

Japanese Patent Laid-Open No. 7-137877 JP 2001-277656 A

  However, the transport technique based on electrostatic adsorption requires a charging device for generating an electrostatic force on the transport belt, which complicates the structure of the transport mechanism and is disadvantageous in terms of cost. In addition, since the ink droplets flying from the inkjet head are also charged, there may arise problems that the straightness of the flight is deteriorated and the image quality is disturbed, or the adsorption force is not stabilized due to changes in temperature and humidity.

  Further, in the above-described transport technology using the adhesive layer on the transport belt, the recording medium is fixed only by the adhesive force of the adhesive layer. Therefore, the adhesive force of the adhesive layer is stronger than necessary, and the recording medium is stuck to the adhesive layer. In some cases, it cannot be separated from the adhesive layer. For example, such a situation is likely to occur when photo paper having a coated surface is conveyed upside down. In such a case, the recording medium may not be corrected, the recording medium may be wound around the belt roller, or the apparatus may be damaged in the worst case.

  The object of the present invention is to simplify the structure of the transport mechanism and reduce the cost, and to prevent the adsorbing force from becoming unstable due to deterioration of the straightness of the flying ink droplets and changes in temperature and humidity. An object of the present invention is to provide a medium conveying belt that can be prevented and conveyed while holding the recording medium with an appropriate adsorption force, and an ink jet recording apparatus including the medium conveying belt.

Means and effects for solving the problems

  In order to achieve the above object, a recording medium conveyance belt according to the present invention has a medium support surface for supporting a recording medium and is formed in an endless shape, and has a leading end on each of the medium support surfaces. A plurality of branched protrusions are formed, and the recording medium can be conveyed while being held on the medium support surface by an intermolecular force generated between each tip of the protrusion and the recording medium.

  In addition, an inkjet recording apparatus according to the present invention includes a recording medium conveyance belt having a medium support surface for supporting a recording medium and formed in an endless manner, traveling means for running the recording medium conveyance belt, and a recording medium conveyance belt An inkjet head that discharges ink onto a surface opposite to the medium support surface of the recording medium supported by the medium support surface, and the recording medium transport belt has a plurality of protrusions with branches at the tips on the medium support surface. And the recording medium is held on the medium support surface by an intermolecular force generated between each tip of the protrusion and the recording medium.

  According to the above configuration, the recording medium can be held with an appropriate adsorption force by the intermolecular force at the tips of the plurality of protrusions formed on the medium support surface. Therefore, a charging device that is necessary when the conveyance technology by electrostatic adsorption is applied is unnecessary, the structure of the conveyance mechanism can be simplified and the cost can be reduced, and the straightness of the flying ink droplet can be improved. It is possible to prevent the adsorption force from becoming unstable due to deterioration or changes in temperature or humidity. In addition, since an adhesive layer having a strong adhesive force is not formed on the transport belt, problems such as the recording medium being wound around the belt roller and the misalignment of the recording medium cannot be corrected can be reduced.

The average thickness of the protrusions is preferably 6 to 8 μm. When the average thickness of the protrusions is made relatively thin, such as 6 to 8 μm, each branch end of the protrusion is further thinned. Although the intermolecular force generated between each very thin tip and the recording medium is very small, a plurality of tips are formed on one projection, and the minute intermolecular force at each tip is gathered to make it more appropriate. Adsorption force is expressed.

  The length of the protrusion is preferably 30 to 130 μm. By making the length of the protrusions relatively long, such as 30 to 130 μm, the protrusions are easily bent when the recording medium is supported on the medium support surface. Therefore, the recording medium is satisfactorily held by the plurality of flexible protrusions.

  The tips of the protrusions are preferably branched into 100 or more. In this case, even if the intermolecular force generated between each tip and the recording medium is very small, the intermolecular force at each of the many tips is summed up so that the intermolecular force at one protrusion is relatively low. growing. Thus, the recording medium can be held with an appropriate adsorption force by a relatively large intermolecular force.

  The thickness of the branched branch of the protrusion is preferably 0.2 to 0.5 μm. When the thickness of the tip of the projection is as thin as 0.2 to 0.5 μm, the intermolecular force generated between each tip and the recording medium is very small, but a plurality of tips are formed on one projection. Therefore, this minute intermolecular force gathers and an appropriate adsorption force is expressed.

  It is preferable that each protrusion has a diameter expanded toward the tip. By making the protrusions have a wide shape as described above, a more appropriate adsorption force is expressed.

It is preferable that 10 to 18 protrusions are formed per 1 cm ^{2 on the} medium support surface. By forming the protrusions at such a density, an appropriate adsorption force can be expressed more effectively.

  Alternatively, it is preferable that the protrusion is formed on a part of a region for supporting the recording medium on the medium supporting surface. More specifically, it is formed only in a region corresponding to two sides parallel to or perpendicular to the conveyance direction of the recording medium, or formed only in a region corresponding to four sides of the recording medium. It is preferable. In these cases, it is advantageous in terms of manufacturing cost and manufacturing process as compared with the case where the protrusion is formed in the entire medium support region.

  The protrusions are preferably formed of polymethyl methacrylate at the base in the vicinity of the medium support surface and carbon nanotubes other than the base including the branched tip. In this case, the flexibility and durability of the protrusion can be ensured.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  First, an overall configuration of an inkjet printer according to an embodiment of the present invention will be described with reference to FIG. The ink jet printer 1 of the present embodiment is a line type color ink jet printer having four ink jet heads 2.

  A head main body 2a is provided at the lower end of each head 2, and the four heads 2 are arranged in parallel along the paper transport direction while bringing the head main bodies 2a close to each other. The head main body 2a has an elongated rectangular plane along a direction perpendicular to the paper surface of FIG. 1 (that is, a direction orthogonal to the paper transport direction), and the length of the head main body 2a is that of the paper P as a recording medium (see FIG. 2). Longer than the width. The lower surface of the head main body 2a is an ink discharge surface 2b in which a large number of nozzle openings (not shown) for discharging ink are formed. The ink discharge surfaces 2b of the four head main bodies 2a are respectively magenta, yellow, and cyan. , Black ink is ejected.

  The ink ejection surface 2b of each head 2 is arranged in the horizontal direction, and the belt conveyance mechanism 13 is arranged such that the ink ejection surface 2b and the upper sheet support surface 8a of the conveyance belt 8 face each other with a small gap. Is arranged.

  The belt conveyance mechanism 13 includes two belt rollers 6 and 7 and an endless conveyance belt 8 wound around the belt rollers 6 and 7, and one belt roller 6 is driven by a motor 40. Accordingly, the conveyor belt 8 travels by rotating clockwise in FIG. 1 (in the direction of the arrow X), and the other belt roller 7 is also rotated accordingly. The rotation of the belt roller 6 is controlled by the controller 50.

  The belt conveyance mechanism 13 also has a belt guide 51 disposed in a region surrounded by the conveyance belt 8. The belt guide 51 has a substantially rectangular parallelepiped shape having the same width as the conveyance belt 8, and the upper surface of the belt guide 51 is in contact with the rear surface of the upper loop of the conveyance belt 8 (that is, the surface opposite to the paper support surface 8 a). The conveyor belt 8 is supported.

  A sheet P (see FIG. 2) as a recording medium is stacked and accommodated in the sheet feeding unit 11 (left side in FIG. 1), and is sequentially sandwiched between a pair of sheet feed rollers 5a and 5b from the top one, and the conveying belt 8 Are fed onto the paper support surface 8a. Then, the paper P is moved below the ink ejection surface 2b of the head 2 as the conveyance belt 8 travels while being held on the paper support surface 8a. At this time, ink of each color is ejected from the ink ejection surface 2b. A desired color image is formed on the paper P. The paper P on which the image is formed in this manner is peeled off from the paper support surface 8a by the peeling plate 10 and sent to the paper discharge unit 12 (right side in FIG. 1).

The paper P transported by the paper feed rollers 5a and 5b is pressed against the paper support surface 8a of the transport belt 8 by the pressing member 9a and, as will be described in detail later, by an appropriate suction force (eg, 1.18 gf / cm ² ) The paper is conveyed while being held on the paper support surface 8a. A pressing member 9b is also provided on the opposite side of the pressing member 9a (that is, on the downstream side in the paper transport direction) with the four heads 2 interposed therebetween.

  Next, the conveyance belt 8 will be described with reference to FIG.

As shown in FIG. 3, the conveyance belt 8 includes a belt main body 8b and a large number of protrusions 18 formed on the paper support surface 8a which is the surface thereof. The protrusions 18 are formed on the paper support surface 8a substantially uniformly at a density of 10 to 18 per cm ² .

  Each protrusion 18 has a substantially cylindrical shape, and is reduced in diameter from the base toward the center in the longitudinal direction, and further expanded from the center in the longitudinal direction toward the tip, with an average diameter D of 6 to 8 μm and a length L of 30-130 μm. The tip 18a of each protrusion 18 branches to 100 or more, and the diameter d of each tip 18a is 0.2 to 0.5 μm.

  The belt body 8b may be made of any material as long as the protrusion 18 can be formed on the surface thereof, such as a polyester base material impregnated with urethane. The protrusion 18 is formed of polymethylmethacrylate at the base in the vicinity of the paper support surface 8a and carbon nanotubes other than the base including the branched tip 18a.

  The paper P sent to the transport belt 8 is placed on the tip 18a of the protrusion 18, and is transported while being held on the paper support surface 8a by the intermolecular force generated between each tip 18a and the paper P. Go.

  As described above, according to the conveyance belt 8 of the present embodiment, the paper P can be held with an appropriate suction force by the intermolecular forces at the tips 18a of the numerous protrusions 18 formed on the paper support surface 8a. it can. Therefore, a charging device that is necessary when the conveyance technology by electrostatic adsorption is applied is unnecessary, the structure of the conveyance mechanism can be simplified and the cost can be reduced, and the straightness of the flying ink droplet can be improved. It is possible to prevent the adsorption force from becoming unstable due to deterioration or changes in temperature or humidity. In addition, since an adhesive layer having a strong adhesive force is not formed on the transport belt 8, problems such as the paper P being caught by the belt rollers 6 and 7 and the positional deviation of the paper P cannot be corrected are reduced. be able to.

  Furthermore, since the protrusion 18 is relatively thin with an average diameter D of 6 to 8 [mu] m, each branched tip 18a of the protrusion 18 is further thinned. Although the intermolecular force generated between each very thin tip 18a and the paper P is very small, a tip 18a branched into 100 or more is formed on one protrusion 18, and the minute molecules at each tip 18a are formed. By gathering the force, a more appropriate adsorption force is expressed.

  Further, since the protrusion 18 is relatively long, 30 to 130 μm, it is easy to bend when the paper P is supported on the paper support surface 8a. Therefore, the paper P is satisfactorily held by the flexible protrusion 18.

  The tips 18a of the protrusions 18 are branched into 100 or more. In this case, even if the intermolecular force generated between each tip 18a and the paper P is very small, the intermolecular force at each of the many tips 18a is summed up, so that the intermolecular force at one protrusion 18 is totaled. Is relatively large. Thus, the sheet P can be held with an appropriate adsorption force by a relatively large intermolecular force.

  Since the diameter d of the branched tip 18a of the projection 18 is very thin, 0.2 to 0.5 μm, the intermolecular force generated between each tip 18a and the paper P is very small. Since the tip 18a is formed, the minute intermolecular force gathers and an appropriate adsorption force is expressed.

  Moreover, each protrusion 18 is expanded in diameter toward the tip 18a, and a more appropriate adsorption force is expressed by having a wide shape.

It is preferable that 10 to 18 protrusions 18 are formed per 1 cm ^{2 on the} paper support surface 8a. By forming the protrusions 18 with such a density, it is possible to more effectively express an appropriate adsorption force.

  The protrusions 18 are formed of polymethyl methacrylate at the base in the vicinity of the paper support surface 8a and carbon nanotubes other than the base including the branched tip 18a. Flexibility and high durability.

  Next, a modified example of the conveyor belt will be described with reference to FIGS. 4 and 5.

  FIG. 4 shows a first modification of the conveyor belt. In the conveyance belt 108 of this modification, the protrusion 18 is formed only in the belt-like region R1 at the center in the belt width direction on the paper support surface 108a. The region R1 extends through the center of the sheet P in the width direction and along the sheet conveyance direction over the front length of the conveyance belt 108.

  FIG. 5 shows a second modification of the conveyor belt. In the transport belt 208 of this modification, the protrusions 18 are formed only in a region R2 corresponding to two sides parallel to the transport direction of the paper P. The region R2 exists so as to straddle the two sides of the paper P, and extends over the front length of the transport belt 208 along the paper transport direction.

  FIG. 6 shows a third modification of the transport belt. In the transport belt 308 of this modification, the protrusions 18 are formed only in a region R3 corresponding to two sides orthogonal to the transport direction of the paper P. Each region R3 extends in a band shape in a direction orthogonal to the transport direction of the paper P, and in the transport direction of the paper P, a distance D1 corresponding to a length in the transport direction of the paper P and a distance shorter than the distance D1. A plurality of D2 and D2 are alternately arranged.

  FIG. 7 shows a fourth modification of the conveyor belt. The conveyor belt 408 of this modification has the protrusions 18 formed only in the region R4 corresponding to the four sides of the paper P. The region R4 has a rectangular frame shape corresponding to each of the four sides of the paper P, and a plurality of regions R4 are arranged at intervals D3 shorter than the length in the paper P transport direction in the paper P transport direction.

  In the third and fourth modifications, it is necessary to control the drive timing of the paper feed rollers 5a and 5b so that the paper P is appropriately supported at positions corresponding to the regions R3 and R4 of the transport belts 308 and 408. There is.

  As in the first to fourth modifications, when the protrusion 18 is formed only in a part of the region that supports the paper P, compared to the case where the protrusion 18 is formed over the entire area of the paper support surfaces 108a, 208a, 308a, and 408a. This is advantageous in terms of manufacturing cost and manufacturing process. Even when the protrusions 18 are formed on a part of the paper support surfaces 108a to 408a in this way, the protrusions 18 are formed in the region that supports the edge of the paper P. It can be held on the paper support surfaces 108a to 408a.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

For example, in the above-described embodiment, the average diameter D of the protrusion 18 is 6 to 8 μm, the length L is 30 to 130 μm, and the tip 18 a of the protrusion 18 is branched into 100 or more. The present invention is not limited to this as long as an appropriate adsorption force can be exerted by the intermolecular force, and each value (thickness and length of the protrusion 18 and the number of branched tips 18a) can be variously changed. Similarly, the diameter of each protrusion 18 is not limited to be increased toward the tip, and the thickness of the tip 18a and the formation density of the protrusion 18 on the paper support surface 18a are not limited to the above values.

  Regarding the material for forming the protrusion 18, in the above-described embodiment, in order to ensure the flexibility and durability of the protrusion 18, the base is made of polymethyl methacrylate and the portion other than the root including the branched tip 18 a is made of carbon nanotubes. However, the present invention is not limited to this, and other materials may be used, and the protrusions 18 may be formed of a single material rather than partially formed of different materials.

  In the first to fourth modified examples (see FIGS. 4 to 7), the example in which the protrusion 18 is formed in a part of the region supporting the paper P on the paper support surface of the transport belt has been specifically shown. As long as the protrusion 18 is formed in a part of the region supporting the paper P, the invention is not limited to this, and various changes can be made.

  The protrusion 18 is not limited to a cylindrical shape, and may have various shapes such as a prismatic shape. Further, the protrusions 18 are not limited to being formed uniformly on the paper support surfaces 8a, 108a, and 208a.

  The number of belt rollers around which the conveyor belts 8, 108, 208, 308, and 408 are wound is not limited to two, and may be three or more.

  The ink jet recording apparatus of the present invention is not limited to a line type and can be applied to a serial type printer, and is not limited to a printer, and can also be applied to a recording apparatus such as a facsimile or a copying machine.

1 is a front view showing an ink jet printer according to an embodiment of the present invention. It is a top view of the belt conveyance mechanism contained in the inkjet printer of FIG. FIG. 3 is a partially enlarged cross-sectional view of the conveyor belt taken along line III-III in FIG. 2. It is a top view which shows the 1st modification of a conveyance belt. It is a top view which shows the 2nd modification of a conveyance belt. It is a top view which shows the 3rd modification of a conveyance belt. It is a top view which shows the 4th modification of a conveyance belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Inkjet head 6,7 Belt roller (traveling means)
8, 108, 208, 308, 408 Conveying belt (recording medium conveying belt)
8a, 108a, 208a, 308a, 408a Paper support surface (medium support surface)
18 Protrusion 18a Protrusion tip 40 Motor (traveling means)
50 Controller (traveling means)
P paper (recording medium)

Claims (13)

A recording medium transport belt having a medium support surface for supporting a recording medium and formed endlessly,
A plurality of protrusions each having a branched tip are formed on the medium support surface,
A recording medium transport belt, wherein the recording medium can be transported while being held on the medium support surface by an intermolecular force generated between each tip of the protrusion and the recording medium. The recording medium transport belt according to claim 1, wherein an average thickness of the protrusions is 6 to 8 μm.   The recording medium conveyance belt according to claim 1, wherein the protrusion has a length of 30 to 130 μm.   The recording medium conveyance belt according to any one of claims 1 to 3, wherein the leading ends of the protrusions are branched into 100 or more.   The recording medium transport belt according to any one of claims 1 to 4, wherein a thickness of the branched tip is 0.2 to 0.5 µm.   The recording medium conveyance belt according to claim 1, wherein each of the protrusions has a diameter increased toward a tip. The recording medium conveying belt according to claim 1, wherein 10 to 18 protrusions are formed on the medium supporting surface per cm ² .   The recording medium conveyance belt according to claim 1, wherein the protrusion is formed in a part of a region that supports the recording medium.   9. The recording medium conveyance belt according to claim 8, wherein the protrusion is formed only in a region corresponding to two sides parallel to the conveyance direction of the recording medium.   The recording medium conveyance belt according to claim 8, wherein the protrusion is formed only in a region corresponding to two sides orthogonal to the conveyance direction of the recording medium.   The recording medium conveyance belt according to claim 8, wherein the protrusion is formed only in a region corresponding to four sides of the recording medium.   12. The projection according to claim 1, wherein the base in the vicinity of the medium support surface is formed of polymethyl methacrylate, and a portion other than the root including the branched tip is formed of carbon nanotubes. The recording medium conveyance belt according to one item. A recording medium conveyance belt having a medium support surface for supporting the recording medium and formed endlessly;
Traveling means for traveling the recording medium conveying belt;
An inkjet head that ejects ink to a surface opposite to the medium support surface of the recording medium supported by the medium support surface of the recording medium conveyance belt;
With
The recording medium conveying belt has a plurality of protrusions each branched at the tip on the medium support surface, and the recording medium is supported by the intermolecular force generated between each tip of the protrusion and the recording medium. An ink jet recording apparatus characterized by being held on a surface.

Images