JP2006192730A - Recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder that can immediately dry ink by performing high-speed drying uniformly on a recording paper having various images formed thereon before the ink permeates the recording paper. <P>SOLUTION: An AC voltage applying region and a DC voltage applying region are provided to a recording paper conveyance region of a conveyance belt. A region where an ink recording head is placed is of the DC voltage applying region. A potential difference is generated between electrodes to attract a recording paper sheet. The AC voltage applying region is provided to a downstream side of the DC voltage applying region. A high frequency AC voltage of 1-100 MHz is applied to electrodes to perform high frequency inductive heating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus in which a configuration is simplified by applying a plurality of functions in each region of a transport belt by applying an AC / DC voltage to a transport belt provided with electrodes.

  Conventionally, in a recording apparatus using an ink recording head, an image is formed by the ink flying from the ink recording head onto a recording medium such as a sheet and landing, and the sheet is directly discharged to a discharge tray and printed. The ink was dried by natural drying.

  However, when the ink is dried by natural drying, an image formed on a recording sheet (especially an image having a large amount of ink shot (DUTY) such as a photograph) is considerably slow to dry. When the hand touches the print section, ink may adhere to the hand. Further, even when paper is ejected, rubbing with a paper ejection roller, a paper ejection paper guide, or the like may cause stains or deterioration of printed products.

  In addition, there is no ink bleed on the special paper with the ink fixing layer or the like provided on the recording paper, but in the case of ordinary plain paper that has not been specially processed, immediately after printing on the recording paper from the ink recording head. The ink soaked into the recording paper, and bleeding occurred when a plurality of colors such as a color image were overlaid, and a clean image could not be obtained.

  In view of these problems, a heating and drying method in which a heater is installed in the vicinity of the printing unit has been proposed. However, since the heating temperature is around 40 to 70 degrees, it is possible to dry the ink to some extent, Drying was difficult.

  In addition, it has been proposed to use a thermal cathode tube as a heater. However, since it is necessary to heat the thermal cathode tube in advance, power consumption is increased and there is a problem in responsiveness.

  Therefore, Japanese Patent Laid-Open No. 3-130158 has been proposed to solve the above problems. According to the technical contents described in these publications, an alternating electric field is formed by a predetermined electric circuit between electrode plates arranged opposite to each other in the main body, and recording paper passes through the recording sheet to perform recording. A method for promoting the drying of the ink on the paper is described.

  However, when passing between the electrode plates, there is a problem that water vapor evaporated from the recording paper adheres to the upper electrode. Therefore, the high frequency AC voltage is applied using the parallel plate shown in FIG. A configuration has been devised.

  On the other hand, the distance between the ink recording head and the recording paper is preferably about 1 mm or less when the ink droplets that form the image are flying in order to obtain a high-definition image, and the printing operation can be performed while maintaining that distance. It has been demanded. In particular, in a high-speed recording apparatus using a long ink head in which a plurality of nozzles are provided in the full width direction orthogonal to the transport direction to enable high speed, the flatness accuracy in a wide area and the distance between the head and the recording paper are constant. High-speed paper conveyance is required while maintaining the same.

In recent years, in order to realize this, a conveying means using a seamless conveying belt in which a plurality of electrodes are provided in a comb-teeth shape in a direction orthogonal to the conveying direction has been devised (see FIG. 5). In this method, a DC voltage (0.5 kv to 10 kv) is alternately applied between the electrodes 122 arranged in a comb-like shape, a potential difference is generated between the electrodes, and the recording paper is adsorbed to the conveying belt by electric force. This enables high-speed conveyance immediately below the recording head while maintaining flatness accuracy.
Japanese Patent Laid-Open No. 3-130158

  FIG. 7 shows a cross-sectional configuration of a print transport unit devised in view of these problems. The conveyance belt 131 rotates in the conveyance direction and sucks the recording paper P (not shown) fed from the upstream in the conveyance direction. In the suction, for example, +1.0 kv is applied to the brush 152a located on the front side in the drawing and 1.0 kv is applied to the back side 152b in the direct current application brush 152, and the belt electrode 22 slides on both ends of the belt. Applied. As a result, a potential difference is generated between the electrodes, and the recording paper is adsorbed by the electric force. The applied voltage value in this case is not limited to the value of this embodiment.

  In the direct current application area, the sheet is adsorbed by the conveyor belt, and the recording sheet passes directly under the recording head in a state where the plane accuracy is maintained. At that time, the ink is ejected from the recording paper to form an image. On the downstream side, the drying means 114 is disposed on the opposite side of the head and the conveying belt. The drying means is composed of electrodes 111 and 112 for applying a high-frequency AC voltage and a case 113 that shields radio waves by covering them, and dries the printed recording paper by high-frequency dielectric heating.

  However, in this configuration, the high-frequency heating device is disposed at a position where the conveyance belt is sandwiched with respect to the recording paper that is the object to be dried. In addition, it is known that the heating efficiency is also affected by the square of the generated electric field. However, this configuration has a problem that it is difficult to arrange them close to each other and the efficiency is not good.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to apply each of the regions of the conveyor belt by applying an AC / DC voltage to the conveyor belt provided with electrodes. In other words, an ink jet recording apparatus having a simplified configuration by providing a plurality of functions is provided.

  In addition, the present invention provides instantaneous drying in an on-demand printing apparatus that performs high-speed printing using a long ink head, and prevents the roller and guides from rubbing due to non-drying and the reduction in image density due to soaking. Another object of the present invention is to provide a recording apparatus that can prevent deformation due to expansion of recording paper due to ink absorption.

  In order to achieve the above object, in the present invention, conveying means using a conveying belt that has electrodes arranged in a comb-like shape and applies a voltage to attract and convey paper by electrostatic force, and opposite thereto In the recording apparatus provided with one or a plurality of recording / printing means at a position to be provided, an AC voltage application region and a DC voltage application region are provided in the recording paper conveyance region of the conveyance belt.

  The area where the ink recording head is arranged is a DC voltage application area, a potential difference is generated between the electrodes to adsorb the recording paper, an AC voltage application area is arranged downstream of the DC voltage application area, and 1 MHz is applied to the electrode. High frequency dielectric heating is performed by applying a high frequency AC voltage of ˜100 MHz.

  Further, as a means for applying a voltage to the electrode in each region, a charging brush that slides with the electrode as the conveying belt is driven is provided.

  Further, the electrode provided on the transport belt is embedded in the transport belt except for a sliding portion with the charging brush.

  Further, the recording means is a long liquid discharge head in which discharge ports are arranged over the entire width of a recording paper printing area orthogonal to the belt conveyance direction.

  Therefore, in an on-demand printing device that performs high-speed printing using a long ink head, instantaneous drying is performed to prevent rubbing contamination of rollers, guides, etc. due to non-drying, and reduction in image density due to penetration, and recording paper It is possible to provide a simple configuration of a recording apparatus that can prevent deformation due to expansion due to ink absorption.

  Further, the recording / printing means is composed of a plurality of liquid ejection heads for ejecting liquid to form an image on recording paper.

  The liquid discharge head may be a thermal jet head that discharges by generating film boiling in the liquid by generating thermal energy.

  As described above, the present invention has been made in order to solve the above-described problems of the prior art, and the object of the present invention is to perform high-speed and surface-uniform drying even on recording paper on which various images have been formed. Thus, it is possible to provide a recording apparatus with a simple configuration that can quickly dry the ink before the ink penetrates. Also, in an on-demand printing device that performs high-speed printing using a long ink head, instantaneous drying is performed to prevent rubbing dirt on rollers, guides, etc. due to non-drying, and reduction in image density due to penetration, and recording paper It is possible to provide a recording apparatus that can prevent deformation due to expansion due to ink absorption, and it is possible to print different images one by one, which is on-demand printing.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

  The recording apparatus according to the embodiment of the present invention will be described with reference to FIGS.

  1 is a schematic sectional view of a recording apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of the recording apparatus according to the embodiment of the present invention, and FIG. 3 is according to the embodiment of the present invention. FIG. 4 is a top perspective view of the conveyance belt, FIG. 4 is a perspective view showing a configuration of the conveyance belt according to the embodiment of the present invention, and FIG. 5 is a dielectric diagram of a formed image and recording paper according to the embodiment of the present invention. It is the graph which showed the rate.

  First, an outline of the apparatus configuration will be described with reference to FIGS.

  The conveyance unit 5 at a position facing the head 7 is constituted by a conveyance belt 31 that is driven by a driving roller 34 and is wound around a conveyance roller 32 that is a driven roller and a pressure roller 35.

  The conveying roller 32 and the driving roller 34 are rotatably attached to the conveying device frame 30, and the pressure roller 35 is rotatably attached to the other end of an arm 50 that is swingably attached to the conveying device frame 30. The arm 50 is pressed by the spring 51 to apply tension (19.6 N) to the conveyor belt 31.

  A pair of suction rollers 33 is arranged at a position downstream of the transport roller 32 so as to sandwich the transport belt 31. The upper roller of the suction roller 33 is pressed against the transport belt 31 by a spring, thereby introducing the recording sheet P. Further, the upper roller of the suction roller 33 is electrically connected to a main body frame (not shown), thereby removing charges accumulated in the surface layer 36d of the conveyor belt 31.

  An upper guide 27 and a lower guide 28 for guiding the recording sheet P are disposed at the entrance of the conveyance belt 31 to which the recording sheet P is conveyed. Further, the upper guide 27 is provided with a PE sensor lever for transmitting the leading edge and trailing edge detection of the recording sheet P to a PE sensor (not shown).

  Further, a recording head 7 that forms an image based on image information is provided on the downstream side of the conveyance roller 32 in the recording sheet conveyance direction.

  In the above configuration, the recording sheet P transported to the transport belt 31 is guided by the upper guide 27 and the lower guide 28 and sent to the suction roller 33. At this time, the leading edge of the conveyed recording sheet P is detected by the PE sensor lever to obtain the printing position of the recording sheet P.

  Then, the recording sheet P is conveyed by the paper feeding motor 60 described later via the driving roller 34 and the conveying belt 31 rotating.

  In the figure, 31 is a conveying belt that moves while adsorbing and holding the recording sheet P, and is made of a synthetic resin such as polyethylene or polycarbonate having a thickness of about 0.1 mm to 0.2 mm, and has an endless belt shape. Yes.

  Reference numeral 52 denotes a DC power supply brush connected to a high-voltage power source (not shown) that generates a predetermined DC high voltage.

  The conveyor belt 31 is provided with a belt electrode 22 which will be described later. When the DC power supply brush 52 applies a voltage of about 0.5 kV to 10 kV to the belt electrode 22, an adsorption force is generated on the conveyor belt 31.

  The conveying roller 32, the driving roller 34, and the pressure roller 35 are rollers that support the conveying belt 31 and apply appropriate tension, and the driving roller 34 is coupled to the paper feed motor 60.

  In the above configuration, the recording sheet P conveyed from the sheet feeding unit is sandwiched between the conveyance roller 31 and the suction roller 33 on the conveyance belt 31 and pressed to the conveyance belt 31 side.

  Then, the recording sheet P is attracted to the flat portion of the transport belt 31 by the electric force generated by the belt electrode 22 to which a voltage is applied from the DC power supply brush 52.

  The recording sheet P adsorbed on the conveying belt 31 is guided to the recording head unit 7, and ink is driven by the recording head while being conveyed at high speed while keeping the distance between the recording paper and the recording head constant. An image is formed. As a result, a high-definition image can be formed at high speed.

  The AC power supply brush 10 is disposed downstream of the recording head 7 independently of the DC power supply brush 52 and is connected to the belt electrode 22 to supply an AC voltage. An exhaust fan 15 is disposed above a region where an alternating current is applied to the belt electrode, and discharges vapor evaporated by dielectric overheating to the outside of the apparatus.

  Reference numeral 53 denotes a static elimination brush which is a static elimination means for the conveyor belt 31. As a result, the charge of the belt is eliminated, and the recording paper is separated from the transport belt and transported to the paper discharge roller.

  Next, the drying means in the present embodiment will be described.

  The high frequency dielectric heating will be briefly described. Water molecules contained in the ink are polar molecules. When these polar molecules are placed in an electric field, they are regularly aligned. Next, when the direction of the electric field is reversed, the arrangement of the water molecules is reversed and moves half a turn. When this is repeated and a high frequency, for example, 40 MHz, is applied, molecular rotational motion is excited and frictional heat is generated between water molecules. Such high-frequency dielectric heating is determined by a dielectric loss factor, which is a heat generation coefficient specific to a dielectric material, and is about 1000 times larger in water molecules than a non-polar material such as a resin film, so other materials are heated. Instead, only water molecules can be rapidly heated and evaporated to dry.

  In the present embodiment, a 43 MHz high frequency alternating current is applied to the belt electrodes 11 and 12 by the alternating current power supply brush 53, and the electric field generated between the electrodes is applied by shifting the phase to the alternating current power supply brushes 53a and 53b. The strength is increased. In general, it is known that the power per unit deposition related to heat generation is proportional to the square of the strength of the electric field, the frequency f, the relative permittivity, and the dielectric loss tangent tTanσ. By actually increasing the electric field, This is because the heating efficiency is improved.

  FIG. 5 is a graph showing the ink ejection amount (printing duty) of the printed recording paper and the dielectric constant of the printed recording paper. By printing in this way, the dielectric constant increases, and even in the same electric field, the dielectric constant of the recording paper itself varies depending on the printed image, and a difference occurs in the heating state. Heating concentrates on the printed portion, and the ink is heated and evaporated in the initial stage. Evaporation reduces unrecorded moisture and decreases the dielectric constant. Immediately after printing, most of the ink has not yet permeated the recording paper on the surface of the recording paper, and when it reaches the drying means, the relative permittivity of water is about 80, so the ink is heated intensively. Will evaporate.

  In this embodiment, printing is carried at a constant belt conveyance speed of 300 / sec, and drying is performed at an output of 2 Kw in order to realize drying in about 0.66 seconds after passing through the drying means. It is dried to a driving amount of 30% d. In uniform 30% duty printing, it is possible to suppress the occurrence of scratches and dirt on the recording paper and the occurrence of wave shapes on the recording paper depending on the moisture absorption and swelling of the recording paper.

1 is a schematic cross-sectional view of a recording apparatus according to an embodiment of the present invention. 1 is a schematic perspective view of a recording apparatus according to an embodiment of the present invention. It is a top view of the conveyance belt which concerns on embodiment of this invention. It is a section perspective view of the conveyance belt concerning an embodiment of the invention. It is the graph which showed the dielectric constant and printing duty of the recording paper which concern on embodiment of this invention. It is a schematic perspective view of the whole recording apparatus based on a prior art. It is a schematic perspective view of the whole recording apparatus based on a prior art.

Explanation of symbols

5 Conveying Section 7 Recording Head 7K Black Head 7M Magenta Head 7C Cyan Head 7Y Yellow Head 10 AC Power Supply Brush 11 Dielectric Heating Electrode 1
12 Dielectric heating electrode 2
13 Case 15 Exhaust fan 16 DC application area 17 AC application area 18 Print area 19 Base 20 Surface layer 22 Belt electrode 25 Upper registration roller 26 Lower registration roller 27 Upper paper feed guide 28 Lower paper feed guide 30 Transport device frame 31 Transport belt 32 Transport roller 33 Adsorption roller 34 Drive roller 35 Pressure roller 36 Adsorption force generation means 38 Spring 40 Humidification means 50 Arm 52 DC power supply brush 60 Drive motor 114 Drying means P Recording sheet

Claims (8)

A recording unit having a comb-teeth-shaped electrode, a conveyance unit using a conveyance belt that applies a voltage and attracts and conveys the paper by electrostatic force, and one or a plurality of recording printing units at a position opposite to the conveyance unit In the device
An AC voltage application area and a DC voltage application area are provided in a recording paper conveyance area of the conveyance belt.   The area where the ink recording head is arranged is the DC voltage application area, a potential difference is generated between the electrodes to adsorb the recording paper, the AC voltage application area is arranged downstream of the DC voltage application area, and the electrode has a high frequency. 2. The recording apparatus according to claim 1, wherein high-frequency dielectric heating is performed by applying an AC voltage.   The recording apparatus according to claim 2, wherein a 1 MHz to 100 MHz band is used as the high frequency voltage.   The recording apparatus according to claim 1, wherein a charging brush that slides with the electrode as the conveying belt is driven is provided as means for applying a voltage to the electrode in each region.   The recording apparatus according to claim 4, wherein the electrodes provided on the conveyance belt are embedded in the conveyance belt except for a sliding portion with respect to the charging brush.   6. The long liquid discharge head in which the recording means is a long liquid discharge head in which discharge ports are arranged in the entire width of a recording paper printing area orthogonal to the belt conveyance direction. Recording device.   The recording apparatus according to claim 1, wherein the recording and printing unit includes a plurality of liquid ejection heads that eject liquid and form an image on recording paper.   The recording apparatus according to claim 7, wherein the liquid ejection head is configured by a thermal jet head that performs film ejection by generating film boiling in the liquid by generating thermal energy.

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