JP2005329716A - Recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out a high speed image printing wherein image quality is high and uniform on both sides of a recording medium which is smooth on front and rear and has a symmetrical structure on the front and the rear by using an ink jet recorder capable of printing both sides. <P>SOLUTION: The recording material Pa has a smoothness below an unevenness of base material provided by applying particular material to front and rear faces of the base material and further has almost symmetrical structure on the front and the rear. The ink jet recorder for carrying out image printing on the recording medium Pa has a housing portion for housing the recording medium Pa; an image printing portion comprising an ink jet recording head 70 for jetting recording liquid on demand in a frequency of several k-40 kHz per one nozzle, wherein nozzles have a sectional area of thousands-tens of thousands pieces in 400-3200 dpi arranging density being 10-600 μm<SP>2</SP>and are extended so as to cover the recording medium; a conveying route 93 for conveying again to the imaging part in order to image the rear surface after imaging the front surface of the recording medium Pa; and a temporary receiving tray 94 which makes the image printing possible so that top and bottom relations of the images on the front and the bottom of the recording medium conform to each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording medium, and more particularly to an ink jet recording apparatus that performs recording on both sides of the recording medium and a recording medium suitable for use in an ink jet copying machine.

The non-impact recording method has recently attracted interest in that the generation of noise during recording is so small that it can be ignored. Among them, the so-called ink jet recording method which can perform high-speed recording and can perform recording without requiring special fixing processing on so-called plain paper is an extremely effective recording method, and various methods have been used so far. Some have been proposed and commercialized with improvements, while others are still being put into practical use.
Such an ink jet recording method performs recording by causing a recording liquid droplet called so-called ink to fly and adhere to a recording member. Depending on the method for controlling the flying direction of the generated recording liquid droplet, there are various methods as follows.

  For example, in the Tele type method (see Patent Document 1), a recording liquid droplet is generated electrostatically, and the generated recording liquid droplet is subjected to electric field control in accordance with a recording signal, and a recording member. There is an electrostatic attraction type in which recording is performed by selectively depositing recording liquid droplets thereon.

  In addition, it is of the Sweet method (see Patent Documents 2 and 3), and a droplet of a recording liquid whose charge amount is controlled is generated by a continuous vibration generation method, and this generated charge amount is controlled. There are a continuous flow type and a charge control type that perform recording on a recording member by flying between deflection electrodes to which a uniform electric field is applied.

  Another method is the Hertz method (see Patent Document 4), in which an electric field is applied between the discharge port and the ring-shaped charging electrode, and droplets of the recording liquid are generated and atomized by a continuous vibration generation method. There is a method of recording. That is, in this method, the electric field strength applied between the ejection opening and the charging electrode is modulated according to the recording signal to control the atomization state of the droplets, and the gradation of the recorded image is recorded.

  Furthermore, as another method, there is a method of the Stemme method (see Patent Document 5). This method is fundamentally different from the above three methods. In other words, all three methods are electrically controlled while the recording liquid droplet ejected from the ejection port is flying, and the droplet carrying the recording signal is selectively attached to the recording member. In contrast, the Stemming method performs recording by ejecting and ejecting small droplets of recording liquid from the ejection port in accordance with a recording signal. That is, in the Stemme method, an electrical recording signal is applied to a piezoelectric vibration element attached to a recording head having an ejection port for ejecting a recording liquid, and the electrical recording signal is converted into mechanical vibration of the piezoelectric vibration element. Recording is performed by ejecting and ejecting small droplets of the recording liquid from the ejection port in accordance with the mechanical vibration and adhering it to the recording member. This is a so-called drop-on-demand type.

  Furthermore, as another method, there is a method (see Patent Document 6) previously proposed by the present applicant. This method is also a so-called drop-on-demand type in which a recording liquid droplet is ejected and ejected from an ejection port in response to a recording signal, but the ink in the liquid chamber is heated to generate bubbles in the ink. This is a so-called bubble ink jet type in which ink droplets are ejected from ejection ports by the acting force of bubbles.

As described above, there are various types of inkjet recording methods depending on the principle, but what can be said in common is that droplets of recording liquid called so-called ink are ejected and adhered to a recording member. This is a recording method based on a very simple principle of recording. Therefore, in recent years, full-scale practical application / spreading has been remarkable, and even things comparable to silver halide photographic image quality have begun to appear, and various applications have begun to be explored from simple printers. As part of such efforts, resource conservation and copier () copying machine applications have been studied, but development has just begun and no definitive technology has been established.
U.S. Pat. No. 3,060,429 US Pat. No. 3,596,275 US Pat. No. 3,298,030 U.S. Pat. No. 3,416,153 U.S. Pat. No. 3,747,120 Japanese Patent Publication No.56-9429

The present invention has been made in view of the above circumstances, and its purpose is as follows.
First, in an ink jet recording apparatus, double-sided printing is performed on a recording medium to achieve resource saving and to obtain good image quality on both sides of the recording medium.
Secondly, in such an ink jet recording apparatus, it is to obtain uniformity in image quality on both sides when duplex printing is performed for the purpose of resource saving.
A third object is to propose an ink jet recording apparatus having a novel configuration that performs such double-sided printing, and to obtain high-quality printing.

Fourthly, in such an ink jet recording apparatus, there is proposed a specific configuration for obtaining higher speed and high quality printing.
Fifth, in such an ink jet recording apparatus, a means for matching the top and bottom relationship of the images on the front and back of the recording medium is proposed.

A sixth object is to propose an ink jet copying machine having a novel configuration utilizing the ink jet recording principle.
A seventh object is to propose means for matching the top and bottom images of the front and back images of a novel ink jet copying machine that performs such double-sided printing.
Eighth, it is to propose a high-speed ink jet copying machine with a novel configuration that performs such double-sided printing.

Ninthly, it is to propose a configuration of a recording medium that can be used in such a novel ink jet recording apparatus to obtain high-quality printing.
The tenth is to propose a configuration of a recording medium that can be used in such a novel ink jet copying machine and obtain high-quality printing.
The eleventh object is to propose a configuration of a recording medium that can be used in such a novel ink jet recording apparatus and copying machine to obtain high image quality printing and uniformity in image quality on both sides.

In order to achieve the above object, the present invention provides
First, a housing member for accommodating the recording medium, the nozzle thousands to several hundred thousand sectional area is 10μm ² ~600μm ² in arrangement density of 400Dpi～3200dpi, the sign of the recording medium Utsushihaba A printing portion comprising an ink jet recording head that ejects recording liquid onto the recording medium on-demand at a frequency of several kHz to 40 kHz per nozzle, and one surface of the recording medium After the printing of the image, the conveying means and the conveying path for conveying again to the printing unit to print the other side, and the printing unit are printed so that the vertical relations of the images on the front and back of the recording medium coincide with each other. A recording medium for use in an ink jet recording apparatus having means for enabling copying, wherein the recording medium is a recording medium formed by applying a particulate material to the front and back surfaces of a base material. The coating of Jo material, characterized in that the irregularities following smooth surface made by said base structure material.

Second, by reading a document image placed on a document table, a scanner unit that sequentially forms image data for the document, a storage member that stores a recording medium, and an array density of 400 dpi to 3200 dpi are several thousand. the nozzle pieces to several tens of thousands of cross-sectional area is 10μm ² ~600μm ^2, as well as lengthening to cover the indicia Utsushihaba of the recording medium, recording a frequency of the number per nozzle kHz~40kHz An ink jet recording head that ejects liquid onto the recording medium on demand is arranged to eject recording liquids of a plurality of colors, and the recording liquid is applied to the recording surface of the recording medium based on image data from the scanner unit. A recording section that performs a recording and printing operation by discharging and adhering the recording medium, and the recording medium is transported to a position opposite to the nozzle surface of the inkjet recording head. Recording means, and after printing one surface of the recording medium, the recording means is transported to the recording unit again to print the other surface and a conveying path, and the recording unit includes the recording medium front and back surfaces. A recording medium for use in an ink-jet copying machine having means for enabling printing so that the upper and lower relations of the images coincide with each other. The recording medium is characterized in that a smooth surface equal to or less than the unevenness formed by the base material constituting material is formed by applying the particulate matter.

  Third, the recording medium according to any one of the first and the second has a substantially symmetrical structure on both sides.

The present invention includes a housing member for accommodating the recording medium, the nozzle thousands to several hundred thousand sectional area is 10μm ² ~600μm ² in arrangement density of 400Dpi～3200dpi, the sign of the recording medium Utsushihaba A printing portion comprising an ink jet recording head that ejects recording liquid onto the recording medium on-demand at a frequency of several kHz to 40 kHz per nozzle, and one surface of the recording medium After the printing of the image, the conveying means and the conveying path for conveying again to the printing unit to print the other side, and the printing unit are printed so that the vertical relations of the images on the front and back of the recording medium coincide with each other. A recording medium for use in an inkjet recording apparatus having means for enabling copying, wherein the recording medium is a recording medium formed by applying a particulate material to the front and back surfaces of a substrate, Since it has a structure with a smooth surface below the unevenness made of the base material by applying the child substance, recording that can be used for such a new ink jet recording apparatus and obtain high image quality printing The medium was realized.

Further, the present invention reads a document image placed on a document table to sequentially form image data for the document, a storage member for storing a recording medium, and an array density of 400 dpi to 3200 dpi. the nozzle thousands to several hundred thousand sectional area is 10μm ² ~600μm ^2, as well as lengthening to cover the indicia Utsushihaba of the recording medium, the frequency of the number per nozzle kHz~40kHz An inkjet recording head that ejects recording liquid onto the recording medium on demand is arranged so as to eject recording liquids of a plurality of colors, and is applied to the recording surface of the recording medium based on image data from the scanner unit. A recording unit that performs a recording printing operation by discharging and adhering a recording liquid, and the recording at a position facing the nozzle surface of the inkjet recording head The recording unit conveys the body and performs recording, and after the printing of one surface of the recording medium, the recording unit transports the recording surface to the recording unit again to print the other surface, and the recording unit. And a recording medium for use in an ink-jet copying machine having means for enabling the images to be printed so that the top and bottom relations of the images on the front and back sides coincide with each other. It is a recording medium formed by coating, and has such a structure that has a smooth surface below the unevenness formed by the base material by applying the particulate matter, so it is used for such a new ink jet copying machine. As a result, a recording medium capable of obtaining high-quality printing was realized.

  In addition, the present invention has a substantially symmetrical structure on the front and back sides of the recording medium used in a novel inkjet recording apparatus and copying machine capable of duplex printing, so that high-quality printing can be obtained and both sides can be printed. The uniformity of image quality was achieved.

The present invention uses an inkjet recording apparatus or copying machine capable of double-sided printing, and prints or copies on a recording medium having a smooth front and back and a symmetrical structure on both sides with high image quality and uniform image quality on both sides. The recording medium is a recording medium formed by coating a particulate material on the front and back surfaces of the substrate, and the substrate structure is formed by coating the particulate material. The recording medium has a smooth surface less than the unevenness made of the material. The recording medium has a storage member for storing the recording medium, and a cross-sectional area of several thousand to several hundred thousand at an arrangement density of 400 to 3200 dpi is 10 μm. ^The nozzles of ^{2 to} 600 μm ² are lengthened so as to cover the printing width of the recording medium, and the recording liquid is jetted on the recording medium at a frequency of several kHz to 40 kHz per nozzle. B An imprinting unit comprising a kjet recording head; conveying means for conveying the other surface to the imprinting unit again after imprinting on one surface of the recording medium; a conveying path; and the imprinting unit Used for an ink jet recording apparatus having means for enabling the images to be printed so that the top and bottom relations of the images on the front and back sides of the recording medium coincide with each other, and a document placed on a platen By reading the image, the original is copied using an ink jet copying apparatus having a scanner unit that sequentially forms image data.
Hereinafter, the recording medium of the present invention will be described with reference to FIGS.

  FIG. 1 is a partial perspective view for explaining an example of a multi-nozzle type ink jet recording head used in the ink jet recording apparatus used in the present invention. The structure of the ink jet recording head shown here is an example of thermal ink jet that can easily realize a high density array with a nozzle array of 400 dpi to 3200 dpi, but is not necessarily limited to this structure. In FIG. 1, 1 is a heating element substrate, 16 is a flow path, 17 is a nozzle (discharge port), 18 is a common liquid chamber, 19 is a ceiling plate, 20 is a bonding layer, and 21 is a flow path barrier. In this example, only three nozzles are shown, but in actuality, as will be described later, this is a multi-nozzle type ink jet recording head that is elongated so as to cover the print width of the recording medium. Thousands to tens of thousands of nozzles are arranged in the printing width direction of the medium.

FIG. 2 shows a heating element substrate used in such a thermal ink jet recording head, FIG. 2 (A) is a perspective view, and FIG. 2 (B) is an arrow A- in FIG. 2 (A). It is sectional drawing which shows the detail of a heat generating body part vicinity by A line sectional drawing, 1 is a heat generating body board | substrate, 2 is 1st electrode (control electrode), 3 is 2nd electrode (earth electrode), 4, 5 is a bonding pad, 7 is a substrate, 8 is a heat storage layer (SiO ₂ ), 9 is a heating element (HfB ₂ ), 10 is an electrode (Al), 11 is a protective layer (SiO ₂ ), 12 is an electrode protective layer (Resin) ), 13 is still another protective layer, 14 is a heating element portion, and 15 is an electrode portion. In order to avoid complication, FIG. 2A shows only a heating element and an electrode part as main parts.

As shown in FIG. 2 (B), the heating element substrate 1 is formed on a substrate 7 made of ceramic such as alumina, glass or Si by a thin film formation technique such as sputtering or a pattern formation technique such as photoetching. SiO ₂ ) 8, heating element (HfB ₂ ) 9, electrode 10, protective layer (SiO ₂ ) 11, electrode protective layer 12, and another protective layer 13 are sequentially formed, and the heating element part 14 and electrode part 15 are formed on the surface part. Is configured. As shown in FIG. 2A, each heating element 9 is connected to a first electrode (control electrode) 2 and a second electrode (earth electrode) 3, respectively, and each electrode is at its end, The first electrode 2 has a bonding pad 4, and the second electrode 3 has a bonding pad 5. The bonding pads 4 and 5 are connected to an external image information input means (not shown), and each generates heat. The body 9 can be driven independently. The second electrode 3 may be a common second electrode for the plurality of heating elements 9, that is, the (first electrode) 2. Further, as in this example, instead of a configuration in which each heating element is driven independently, a configuration in which matrix driving is performed may be employed. Such a row of heating elements 9 is, for example, an arrangement density of 400 dpi to 3200 dpi, as in the case of the nozzle arrangement, and several thousand to several hundred thousand pieces depending on the required printing width of the recording medium. Nozzles and heating elements are provided.

A heat storage layer 8 is formed on the substrate 7. The heat storage layer 8 is for preventing heat generated by a heating element 9 described later from escaping toward the substrate 7. That is, the generated heat is efficiently transmitted to the ink so that stable bubbles are generated in the ink. Usually, as the heat storage layer 8, SiO ₂ is used to form a SiO ₂ film thickness of 1μm~5μm using a deposition technique such as sputtering.

As shown in FIG. 2B, a layer of a heating element 9 is formed on the storage layer (SiO ₂ ) 8. A material useful as a material for the heating element 9 is tantalum-SiO _{2. And} a boride of a metal such as tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor, or hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, and vanadium. Among metal borides, hafnium boride (HfB ₂ ) has the most excellent characteristics, followed by zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride. ing.

The heating element 9 can be formed using the above-described materials by a technique such as electron beam evaporation or sputtering. The film thickness of the heating element 9 is determined according to its area, material, shape and size of the heat acting part, and actual power consumption, etc., so that the amount of heat generated per unit time is as desired. However, in the usual case, the film thickness is 0.001 to 5 μm, preferably 0.01 to 1 μm. In the embodiment of the present invention, an example in which HfB ₂ was sputtered to a thickness of 2000 mm (0.2 μm) was shown.

  As the material constituting the electrode 10, many commonly used electrode materials are effectively used, and specific examples thereof include Al, Ag, Au, Pt, Cu and the like. Using these, it is provided in a predetermined position with a predetermined size, shape and thickness by a technique such as vapor deposition. In the present invention, Al is formed to have a thickness of 1.4 μm by sputtering.

The properties required for the protective layer 11 are ink corrosion resistance and protection from impact force due to the disappearance of bubbles (cavitation resistance), and the heat generated by the heating element 9 is transferred to thermal paper, an ink ribbon, Alternatively, it is effectively transmitted to the ink that is the recording liquid.
Examples of useful materials for forming the protective layer 11 include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, and zirconium oxide, which are formed using a technique such as electron beam evaporation or sputtering. can do. Ceramic materials such as silicon carbide and aluminum oxide (alumina) are also preferably used materials.
The thickness of the protective layer 11 is usually 0.01 μm to 10 μm, preferably 0.1 μm to 5 μm, and most preferably 0.1 μm to 3 μm. In the present invention, 1.2 μm of SiO ₂ is formed by sputtering.

  FIG. 2B shows an example of the electrode protective layer 12 and another protective layer 13, but a Resin layer of 2 μm was formed as the electrode protective layer 12. This is provided as necessary, but is not necessarily required and may be omitted. As the material of the protective layer 13, tantalum (Ta) is preferably used in consideration of cavitation resistance. Since a cavitation impact force due to the generation of bubbles is applied in the heating element region, good performance can be obtained by forming Ta with a thickness of 4000 μm (0.4 μm) by sputtering in order to protect against destruction.

  An ink jet recording head can be configured by using such a heating element substrate 1, and specifically, it can be manufactured by a construction method as shown in FIG. In FIG. 3, 19 is a ceiling plate, 20 is a bonding layer, 21 is a flow path barrier, 22 is a photoresist, and 23 is a photomask. The manufacturing process of the inkjet recording head will be described with the following (A) to (F).

(A) A heating element substrate is prepared (FIG. 3A).
In the heating element substrate 1, a heating element 9 and a thin film 11 that protects and insulates the heating element 9 are formed on a substrate 7.

(B) A photoresist is coated on the heating element substrate (FIG. 3B).
For example, a photoresist 22 having a viscosity of 1000 cP to 2000 cP (centipoise) is coated on the heating element substrate 1 shown in FIG. 3A to a thickness of about 3 μm to 30 μm by spin coating, dip coating, or roller coating. . This thickness finally becomes the height of the flow path barrier 21, and the height varies depending on the arrangement density (printing density) of the heating elements 9. In order to obtain a layer of photoresist 22 having a thickness of 20 μm or more, a dry film type photoresist may be used instead of a liquid photoresist. Subsequently, as shown in FIG. 3B, after a photomask 23 having a predetermined pattern is overlaid on a photoresist 22 provided on the surface of the heating element substrate 1, exposure is performed from above the photomask 23. . At this time, it is necessary to align the installation position of the heating element 9 and the pattern.

(C) A flow path barrier is formed (FIG. 3C).
The photoresist 22 and the unexposed portion of the exposed photoresist 22 are removed with an alkali developer such as an aqueous sodium carbonate solution to form the flow path barrier 21. The removed portion becomes a recess having the heating element 9 and constitutes the flow path 16 and the common liquid chamber 18.

(D) A substrate to be a ceiling of the flow path and the common liquid chamber is created (FIG. 3D).
The substrate serving as the ceiling of the flow path 16 and the common liquid chamber 18 is obtained by bonding the bonding layer 20 and the glass substrate 19, and the glass substrate serves as a ceiling plate.

(E) The substrate is bonded to the flow path barrier (FIG. 3E).
The heating element substrate 1 and the glass substrate serving as the ceiling plate 19 are bonded with the photoresist 22 and the bonding layer 20 facing each other. At that time, thermosetting treatment (for example, heating at 150 to 250 ° C. for 30 to 60 minutes) or ultraviolet irradiation (for example, 50 mW / cm ^{2 to} 200 mW / cm ² , or higher ultraviolet intensity) Improve ink properties and bond strength.

(F) A discharge port is formed (FIG. 3 (F)).
Finally, the portion of the YY line near the opening on the side of the heating element 9 is cut by dicing to form the discharge port 17 to complete the ink jet recording head. In this case, the nozzle size is 3 μm × 3 μm to 30 μm × 30 μm according to the resist thickness.

  As another manufacturing means, there is a method of manufacturing the flow path and the common liquid chamber by integral molding of a resin such as polysulfone, polyethersulfone, polyphenylene oxide, polypropylene, and polyimide.

In addition, a means for forming a nozzle by arranging a resin film at the tip of the flow path, perforating the discharge port by means such as an excimer laser, and the like is also preferably used. With the excimer laser ejection port drilling method, nozzles of any shape can be formed depending on the mask shape, so the shape can be changed in consideration of the relationship with the ink ejection characteristics such as round shape, polygonal shape, or star-shaped radial shape. This is an advantageous method because it can be determined. Also in this case, resins such as polysulfone, polyethersulfone, polyphenylene oxide, polypropylene, and polyimide can be used favorably. In the present invention, a more preferable nozzle size is 3 μm × 3 μm to 25 μm × 25 μm (this example is a square nozzle, but in terms of cross-sectional area, it is about 10 μm ^{2 to} 600 μm ² , and other nozzle shapes In the case of, the dimensions are converted based on this cross-sectional area).

This is determined in view of the final print density, but other important factors include ink drying issues. This is because, in the case of a nozzle that is too large, for example, a nozzle larger than 30 μm × 30 μm (in terms of cross-sectional area, about 1000 μm ² or more), the ink droplets also become large. This is because it takes a long time to dry the ink. A similar problem arises when a serial scanning method is employed instead of nozzles arranged over the entire width of the paper, the number of nozzles is 500 to 1000 or more, and the entire surface is printed. Therefore, a suitable nozzle size is 3 μm × 3 μm to 25 μm × 25 μm.

As far as ink drying is concerned, the volume of the ink works in the third power with respect to one side of the nozzle (here, described as a rectangular nozzle), so as described above, one side is 25 μm or less (in terms of cross-sectional area). , About 600 μm ² or less), the volume of one ink droplet is also rapidly reduced, which is very advantageous.

In particular, when performing double-sided printing as in the present invention, the problems of ink drying and paper penetration are more severe than conventional single-sided printing. In order to realize fast throughput (number of printed images per unit time) and to realize fast drying of ink (in terms of cross-sectional area conversion) About 600 μm ² or less).

On the other hand, the lower limit is 3 μm × 3 μm or more (about 10 μm ² or more in terms of cross-sectional area) in consideration of stable ejection of minute ink droplets. This is because if it becomes finer than this, it becomes a mist rather than an ink drop and floats in the air, making it difficult to drive it to a desired position on the paper as the recording medium.

  Next, the principle of ink ejection by such an ink jet recording head will be briefly described with reference to FIG. In FIG. 4, 31 is ink, 32 is a bubble, 33 is a discharge port, 34 is a flow path, 35 is a heating element substrate, 36 is a heating element, 37 is a first electrode (control electrode), and 38 is a second electrode (ground). Electrode), 39 is an ink droplet. A signal pulse is input to the heating element 36 in accordance with image information via the first electrode 37 and the second electrode 38, and bubbles 32 are generated in the ink in response to the input pulses. A part of the ink 1 in the flow path 34 is ejected as an ink droplet 39 from the ejection port 33 and recorded on a recording medium (for example, paper).

  Here, the duration of the signal pulse is preferably several μs to several tens μs, and is set to 30 μs at the longest. This is because once the bubble 32 is generated on the heating element 36, the bubble 32 blocks the heat of the heating element 36, so that the size of the bubble 32 hardly changes and is unnecessarily long. This is because energization not only wastes but also damages the heating element 36. After the energization is stopped, the bubbles 32 are deprived of heat by the heating element substrate 35 and the surrounding ink 31 and contract and disappear. As is clear from this explanation, the bubbles 32 acting on the ink jetting principle in the present invention are bubbles obtained by abrupt heating in a very short time. It is a bubble of a phenomenon called boiling, and the reproducibility of generation to disappearance is very good.

Further, as another ejection principle, the position of the heating element 36 shown in FIG. 4 is brought close to the ejection port 33 so that a finer ink droplet is ejected, or the generated bubbles protrude to the outside of the ejection port 33. Or you may make it burst.
Further, the above description has been made based on the example of the thermal ink jet method including the manufacturing method of the ink jet recording head. However, an ink jet method using a piezo element may be used.
As another ink jet method, there is a charge control method (also referred to as a continuous flow type). However, since the structure is complicated, the present invention uses the above-described thermal ink jet method or an on-demand type using a piezo element or the like. An ink jet system (a type that ejects ink droplets as necessary) is preferably used.

  Further, in the present invention, the multi-nozzle is formed so as to cover the printing width, but the drive frequency of the recording head (ink droplet discharge frequency) is used by driving on demand at several kHz to 40 kHz per nozzle. Is done. In the case of the charge control method, there is an ability to form ink droplets at 100 kHz to 1 MHz per nozzle (form 100000 to 1000000 ink droplets per second), but the present invention covers the printing width. Therefore, it is sufficient to drive at several kHz to 40 kHz per nozzle.

  FIG. 5 shows a recording section 70 of a multi-nozzle type ink jet recording apparatus in which a plurality of ink ejection openings as used in the present invention are elongated so as to cover the printing width of the recording medium. is there. The recording unit 70 includes a head block 72 that incorporates the recording heads 70C, 70M, 70Y, and 70B and a heating-type fixing device 76 described later. The head block 72 is supported inside the recording unit 70 via protrusions 72A provided at both ends along the conveyance path of the recording medium (paper Pa).

The recording heads 70C, 70M, 70Y, and 70B are sequentially arranged with a predetermined mutual interval from the upstream side to the downstream side of the paper Pa conveyance path. At this time, the recording heads 70C to 70B are positioned and fixed to the head block 72 so that the flatness of the plane formed by all the ejection port surfaces of those heads is within several tens of microns.
Each of the recording heads 70C, 70M, 70Y, and 70B is, for example, the thermal ink jet method as described above, and ejects cyan, magenta, yellow, and black inks. That is, each of the recording heads 70C to 70B has a heater as an electrothermal converter in a liquid flow path leading to the discharge port, and discharges ink droplets formed when the ink is heated by the heater. Is done. Each of the recording heads 70 </ b> C to 70 </ b> B has a plurality of ejection openings arranged along a direction substantially orthogonal to the conveyance direction of the paper Pa. The plurality of ejection openings are formed over the entire width in a direction substantially orthogonal to the conveyance direction on the recording surface of the paper Pa.

  The recording operation of each of the recording heads 70C, 70M, 70Y, and 70B is performed on the same sheet of paper Pa. For example, the recording head 70C performs recording first, and the recording head second. It is assumed that the recording surface 70C is overlapped or recorded at a new position, the third recording head 70Y performs recording in the same manner, and finally the recording head 70B performs recording. The recording heads 70 </ b> C to 70 </ b> B are not limited to those that eject ink, and, for example, at least one recording head may eject processing liquid that insolubilizes ink. Alternatively, the processing liquid may be discharged to prevent the pixels from spreading on the paper Pa more than necessary or bleeding before the ink discharge. Note that the printing order of each color does not necessarily have to be the order shown here.

  In such an ink jet recording system, ink adhered to a recording material permeates into the recording member, and the ink is fixed to the recording member. Alternatively, the adhered ink is fixed on the recording material through an evaporation process of the ink solvent. However, the time from the ink adhesion to fixing, that is, the fixing speed, not only greatly depends on the configuration and physical properties of the recording material, but also greatly depends on the state of the external atmosphere. Also, the natural fixing speed cannot be shorter than a certain time due to physical characteristics.

As described above, the speed at which the ink adheres to and penetrates the recording material also varies greatly depending on the composition of the ink used.
Usually, the ink composition is often distinguished by the degree of permeability of the ink to the recording material. In general, ink with high penetrability is advantageous from the viewpoint of fixability because of its high penetrating speed with respect to the recording material, but on the other hand, since it penetrates too much, there are many blurs on the recording material. The problem is that the quality deteriorates. Further, since the ink penetrates deeply into the recording material, it tends to lead to a decrease in image density.

  On the other hand, when an ink with low penetrability is used, as described above, it takes time to penetrate, and from the viewpoint of fixability, a recording medium that requires high speed as in the present invention. In a multi-color printing device that uses a multi-nozzle inkjet recording head that is elongated to cover the printing width, ink mixing and bleeding between ink colors, and recording material discharge Scratching of the image at the time, a so-called scratch resistance problem arises. Therefore, it is important to configure the apparatus in consideration of fixability, image density, bleeding, and scratch resistance.

Further, as will be described later, the paper to be used is a coated paper having a surface coated with a substance that can instantly absorb ink without smearing. For example, a coated paper coated with a particulate material such as finely divided silicic acid is preferably used.
In conventional serial scan recording apparatuses, such fixability can often be dealt with with a somewhat simple configuration because of the recording speed.

However, in particular, when high-speed recording and color recording are performed as in the embodiments of the present invention, as described above, fixing is performed in order to fix the ink applied to the recording material in a desired state on the recording material. It is desirable to provide a heating-type fixing device 76 as described below for speed reduction and efficiency improvement.
For example, as shown in FIG. 5, the heating type fixing device 76 is provided on the downstream side of the recording head 70 </ b> B in the conveyance path and corresponding to a relatively close position. Here, an example in which the heating type fixing device 76 includes a halogen heater 84 and a reflection plate 82 that reflects heat rays from the halogen heater 84 is shown.
As in this example, in the ink jet recording apparatus used in the present invention, the printing surface side of the recording medium (paper Pa) is heated in a non-contact manner. That is, since the printing part is heated from the surface, volatile components in the ink such as water can be efficiently dried.

  Here, as the heating-type fixing device 76, a halogen heater 84 as a heating unit, a reflection plate 82 that reflects heat rays from the halogen heater 84, a heating unit shielding member 86 that partitions the halogen heater 84 and the conveyance path, and Although an example of a configuration including a heat insulating device 78 as a heat insulating portion that cuts off heat transfer from the halogen heater 84 to the recording head 70B is described as an example, a brief description will be given below.

  In this embodiment, the halogen heater 84 is disposed adjacent to the recording head 70B in the vicinity of the most downstream side in the conveyance direction of the paper Pa in the recording unit 70. This is because it is necessary to heat and fix the halogen heater 84 immediately after the image recording is completed. The halogen heater 84 heats the recording surface in a non-contact manner. As a result, the recording surface is dried, the drying of the ink is promoted, and the fixing speed is greatly improved. Further, since it is non-contact, it can be avoided that the dot shape on the recording surface of the paper Pa is broken and can be dried without degrading the image quality.

The heating operation of the halogen heater 84 is controlled at a predetermined timing according to the conveyance of the paper Pa and the recording operation of the recording unit 70 by the control unit 100 described later. Further, the halogen heater 84 is provided with a thermostat (not shown) for controlling the temperature of the halogen heater 84. According to the temperature set by the thermostat, the fixing temperature is appropriately controlled in accordance with conditions such as the paper quality of the recording member, the conveyance speed, and the image density.
The heating unit for heating the surface (recording surface) to which the ink of the paper Pa is attached is not limited to the halogen heater 84, and may be a halogen lamp, a sheathed heater, a ceramic heater, a thermistor, or the like. Good.

Further, the heating portion shielding member 86 is made of a wire mesh or the like in consideration of the safety aspect when the paper Pa is jammed, and is disposed at a position covering the surface of the halogen heater 84 from the lower side.
The reflection plate 82 having one end connected to the heat insulating device 78 is made of, for example, bright alloy aluminum or the like, and has a curved portion that covers the halogen heater 84 from above. The curved portion of the reflecting plate 82 is set so that the heat rays from the halogen heater 84 are reflected by the inner surface of the curved portion of the reflecting plate 82 and the heat rays reach the recording surface most efficiently. In addition to the reflection plate 82, for example, the light from the lamp light source may be condensed on the surface (recording surface) of the paper Pa where the ink is adhered by an optical system of a lens system. In addition, when a light / heat condensing optical system is formed by combining a reflecting plate and such a lens system optical system, it can be dried more efficiently.

  As shown in FIG. 5, the heat insulating device 78 is connected between the recording head 70 </ b> B and the halogen heater 84 in the head block 72 and close to the recording head 70 </ b> B. The heat insulating device 78 is made of, for example, a plate-like member made of an aluminum alloy having a good heat dissipation property or a heat-resistant plastic material bonded with a material having a good heat dissipation property such as an aluminum sheet. The heat insulating device 78 has a substantially rectangular cylindrical cross-sectional shape. That is, in the heat insulating device 78, an air layer 80 is formed in the inside thereof so as to extend along the ejection port arrangement direction of the recording head 70B. Moreover, the both ends of the up-down direction of the heat insulation apparatus 78 are respectively opened with respect to the exterior.

  Accordingly, heat transfer from the halogen heater 84 to the recording head 70B is cut off, and the temperature rise of the recording heads 70C to 70B due to high heat is prevented. Further, the heat generated from the halogen heater 84 is conducted to the heat insulating device 78 through the reflection plate 82 and is radiated.

  Next, features of the present invention will be described with reference to FIG. FIG. 6 is viewed from the direction of arrow A of the recording unit 70 of the multi-nozzle ink jet recording apparatus in which the plurality of ink discharge ports shown in FIG. 5 are elongated so as to cover the print width of the recording medium. A partial schematic diagram is shown. As is apparent from this figure, in the ink jet recording apparatus used in the present invention, the heating means 90 is printed by the multi-nozzle recording heads 70Y, 70B and the like elongated in the width direction of the recording medium (Pa). It covers the range larger than the printed width. That is, if the area heated by the heating means 90 is larger than the printing width, the heating capability is more than that when only the printing width is heated. Can be dried. More preferably, as shown in FIG. 6, it is more effective to set the area heated by the heating means 90 to a range larger than the width of the recording medium (Pa).

The heating-type fixing device 76 is provided after the recording head 70B (provided on the most downstream side of the conveyance of the recording medium (Pa)). A plurality of such heating means are prepared, and each recording head 70C is provided. , 70M, 70Y, 70B adjacent to each other, it is more effective to perform ink drying at the same time as printing with each color ink is completed, and at the same time, the inks of each color are mixed before drying, The problem that the image quality is lowered due to the dull color can also be solved.
Further, more effective ink drying can be achieved by arranging a heating means on the upstream side of the recording head 70C so that the recording medium (Pa) is heated in advance before printing by the recording head 70C starts. .

  Next, another feature of the ink jet recording apparatus used in the present invention will be described with reference to FIG. FIG. 7 shows an example in which a back side heating means 90 is provided so that the recording medium (Pa) can be heated from the back side of the surface to be printed. Also in this case, the back surface side heating means 90 extends in the multi-nozzle row arrangement direction and covers a range larger than the printing width of the recording medium (Pa) so as to perform effective heating. . Further, more effective heating / drying can be realized by setting the heated region to be larger than the width of the recording medium (Pa).

  FIG. 8 shows a case where such a back surface heating means 90 is brought into contact with the conveyor belt 40 for more effective heating / drying. In this case, the recording medium (Pa) is heated via the conveying belt 40 for conveying the recording medium (Pa). However, instead of the conveying belt 40 as another conveying means, for example, a drum structure (or roller) conveying means may be used. If the recording medium (Pa) is directly heated using the (roller) itself as a heating drum (roller), more effective heating / drying is possible.

  FIG. 9 is a diagram for explaining still another feature of the ink jet recording apparatus used in the present invention. In this example, C, M, Y, and B (cyan, magenta, yellow, and black inks) are referred to. A heated air flow is blown by the warm air applying means 91 on the surface to be printed after the printed papers that have been printed in order and conveyed, and the moisture in the ink is evaporated by non-contact means, followed by drying and fixing. It is something to be made.

The hot air applying means suitably applied to the ink jet recording apparatus used in the present invention will be described in detail with reference to FIG. FIG. 9 or FIG. 10 schematically shows the hot air applying means 91, and basically includes an air blowing means 91a, a heating means 91b, and a hot air applying area (hot air blowing port) 91c.
As the air blowing means 91a, a fan as illustrated, a pump, a compressor, an accumulator combined therewith, or the like is used. As the heating means 91b, a halogen lamp, a sheathed heater, a ceramic heater or the like can be used in addition to the joule resistance heating of the nichrome wire.

  Such a heated air flow (warm air) formed by the combination of the air blowing means and the heating means extends in the direction perpendicular to the paper surface of the drawing, and if expressed in another form, is a slit shape extending in the direction of arrangement of the multi-nozzle rows. It is blown from the opening (warm air blowing port) 91c to the surface to be printed after printing. The slit-shaped opening covers a range larger than the printing width of the recording medium, thereby more effectively evaporating the water in the ink, and drying and fixing.

  Next, the temperature of the heated air flow (warm air) is used. In order to more effectively evaporate the water in the ink and dry and fix it, a recording medium (paper is generally used) Plastic sheets and the like also fall within the category of the recording medium of the present invention.) This is because if the hot air blown is lower than the temperature of the recording medium, it is not very effective for moisture drying.

  In the ink jet recording apparatus used in the present invention, the water in the ink is evaporated and dried and fixed by such warm air applying means, and the more effective drying and fixing are shown in FIG. It is preferable to combine the heating-type fixing device 76 as described above, or the back surface side heating means and the hot air applying means as shown in FIGS. At that time, since the recording medium is heated to a certain temperature by such a heating type fixing device, the back surface side heating means, etc., there is not much effect if the hot air blown is lower than that temperature. Therefore, in the present invention, hot air having a temperature higher than the surface temperature of the recording surface after recording is blown.

  As a preferred example, the recording surface of the recording paper is heated to 40 ° C. to 65 ° C. in the paper conveyance path before printing, during printing, or after printing, and is heated by a nichrome wire heater after printing. In addition, by blowing air at 70 ° C. to 150 ° C. with a fan, drying was performed quickly, and even if the printed matter after printing was overlapped, a good printed matter that did not show through was obtained.

  Next, other features of the ink jet recording apparatus used in the present invention will be described. In the present invention, the undried ink on the recording medium (on the paper surface) is dried and fixed, or the non-penetrating ink on the recording medium (on the paper surface) is dried and fixed. Such undried or non-penetrated ink is a state in which an ink meniscus is formed on a recording medium (on the paper surface) (a state where ink droplets are dome-shaped on the recording medium), or When a little more time has passed since then, the ink meniscus has collapsed and is in a flat state, but in any case, it is wet with ink.

  In such a state, when warm air is blown as described above, depending on the blowing condition, not only water in the ink is dried, but also wet ink is scattered, which may cause image quality deterioration. In view of this point, the ink jet recording apparatus used in the present invention has been studied under conditions that do not scatter wet ink or cause image quality deterioration.

  In general, air is a viscous fluid, and there are laminar and turbulent flows. Now, when considering the flow in a circular pipe, the flow in which fluid particles in each layer in the tube flow parallel to the tube axis is called laminar flow, and the fluid particles in each layer enter each other and mix irregularly. The moving flow is called turbulent flow. Therefore, when other fluids (ink droplets, ink meniscus, etc.) are present in the turbulent flow, they are caught in an irregular flow and the fluid is scattered. In the case of the example of the present invention, unnecessary scattered ink will fly and lead to image quality deterioration, and such a state should not be created.

More quantitatively, when the kinematic viscosity coefficient of the fluid is γ, the average flow velocity is u, and the inner diameter of the pipe is d,
R = ud / γ
The dimensionless number represented by (this is called the Reynolds number) is less than a certain value is called laminar flow, and the case of more than that is called turbulent flow. The Reynolds number when transitioning from turbulent flow to laminar flow and laminar flow to turbulent flow is called critical Reynolds (Rc).
Rc = 2310
(Normally, the critical Reynolds number refers to the lower critical Reynolds number, so here the value of Rc is also the lower critical Reynolds number).

For example, if the inner diameter d of the tube is 2 mm, the dynamic viscosity coefficient γ of air is about 235.1 × 10 ⁻⁷ m at 1 atm and 100 ° C. ^{Since 2} / s, transforming the above equation and substituting these numbers,
u = Rc × γ / d
= 2310 × 235.1 × 10 ⁻⁷ (m ² / s) / 2 (mm)
≒ 27.2 (m / s)
Thus, a laminar flow can be obtained if the air flow rate is about 27.2 m / s or less.
A large number of such tubes are arranged in the multi-nozzle row arrangement direction so as to cover a range larger than the recording width of the recording medium. In the case of a slit-like opening, although the conditions are strictly different, it can be considered almost the same.

The above calculation example is an example, but the size, shape, flow velocity, and the like of the opening that achieve such a lower critical Reynolds number are appropriately selected. FIG. 10 shows two examples (A) and (B) when the size of the opening is changed.
If the hot air generated under such conditions is trapped in the device, the device itself will be overheated, causing a malfunction of the electrical system, or if the confidentiality in the device is too high, it will be in a high pressure state. For this reason, the ability to generate hot air that is sequentially generated decreases. Therefore, in the ink jet recording apparatus used in the present invention, an air flow path for discharging hot air in the apparatus is taken into consideration, and an opening for efficiently releasing the hot air to the outside of the apparatus is provided.

Next, other features of the ink jet recording apparatus used in the present invention will be described with reference to FIG. In the present invention, for the purpose of saving resources of a recording medium (mainly paper is used), it has been studied to print on both sides of the recording medium. At that time, the recording medium once printed on one side is conveyed again to the printing unit and printed for printing on the back side.
As shown in FIG. 11, the recording medium Pa transported along the Pa traveling direction is printed by the recording heads 70C, 70M, 70Y, and 70B, and then the transport path is set according to the application. Divided into two. First, in the case of ending only with one-sided printing at the beginning, the paper is discharged as it is along the left arrow in the figure, and the printing is finished.

  Next, when performing double-sided printing, a signal is sent to the separation claw 92 in the figure, the separation claw 92 is operated so as not to go in the direction of the left arrow in the figure, and the recording medium Pa is used for double-sided printing. It is transported toward the transport path 93. At the end of the double-sided printing conveyance path 93, there is a double-sided printing paper temporary storage tray 94 for storage. As can be seen from the drawing, when separated from the separation claw 92 and rotated counterclockwise and conveyed on the duplex printing conveyance path 93, the printing surface is directed downward. Therefore, the printing surface is also faced downward when it is stored in the double-sided printing paper temporary storage tray 94.

  Thereafter, when printing on the other side, the double-sided printing paper temporary storage tray 94 is transported toward the double-sided printing transport path 95 by the transport roller 96. Since it faces downward, as shown in the figure, the next printing surface (rear surface) is conveyed along the double-sided printing conveyance path 95 so that the nozzle surface of each recording head in the printing portion. It comes to be relative to.

  In this case, when the next printing, that is, the printing of the other side on the opposite side (printing on the back side) is performed on the recording medium Pa conveyed through the conveyance path 95 for double-sided printing, the front surface The vertical relationship is reversed with respect to the surface that has already been printed. Therefore, when the printing (printing on the back side) is performed, it has a memory for storing image data for one sheet of printing on the back side, and the printing is performed from the lower side of the other side. In addition, printing control is performed so that the data is sent to the recording heads 70C, 70M, 70Y, and 70B from the opposite direction. Accordingly, a complicated mechanical conveying means is not required for conveying the recording medium (paper), and printing can be performed so that the upper and lower relations of the images on the front and back of the recording medium coincide with each other by electrical control.

  Alternatively, as another means, in the double-sided printing paper temporary storage tray 94, the rotation control mechanism (not shown) rotates the direction of the paper printed and conveyed into the tray by 180 degrees by the mechanical means. It is also a good method. When such a means is adopted, the recording medium (paper) Pa front and back images can be printed when double-sided printing is performed without performing printing control for sending image data from the opposite direction as described above. Can be printed so that the vertical relationship matches.

As another means, a path is formed that passes through the double-sided printing conveyance path 93 shown in FIG. 11 and goes to the double-sided printing conveyance path 95 without going to the double-sided printing paper temporary storage tray 94. A twisted path in which the front and back of the recording medium (paper) Pa are reversed 180 degrees in the middle of the path from the duplex printing conveyance path 93 to the duplex printing conveyance path 95 is also a good means. In this case, the orientation of the image on the front and back of the recording medium can be reversed naturally during conveyance without specially changing the orientation of the top and bottom of the recording medium Pa. You can print as you do.
In any case, in the ink jet recording apparatus used in the present invention, even when double-sided printing is performed by the above-described means or the like, the vertical relationship of the images is made to coincide on the front and back of the recording medium (paper). ing.

  Here, after printing again (double-sided printing is completed), this time, the separation claw 92 is not operated, and the paper is discharged as it is along the left arrow in the figure, and the printing is completed. Although not all are shown in the figure, large and small circles indicate the conveyance rollers.

  Next, still another feature of the ink jet recording apparatus used in the present invention will be described. In the present invention, as described above, after the recording medium is once printed on one side, the recording material passes through the double-sided printing conveyance path 93, the double-sided printing paper temporary storage tray 94, and the double-sided printing conveyance path 95. The non-printing surface (back surface) of the medium is conveyed again to the printing unit. At that time, the problem is the drying of the ink on the recording surface which is first printed. In particular, in a recording apparatus in which a multi-nozzle is formed so as to cover the printing width as in the present invention and one printing is completed in a short time, the ink drying time is not sufficient and the next printing is not performed. Since the copying operation can be performed (meaning that the recording head has the capability), it is necessary to sufficiently consider the ink drying after the printing.

  In view of this point, in the ink jet recording apparatus used in the present invention, as described above, when performing double-sided printing, after the single-sided printing, the recording medium Pa conveyed to the double-sided printing conveyance path 93 is temporarily transported. I try to stop it. By doing so, the ink drying time can be taken. The stop time is determined by natural drying or by forced drying as described later, and further takes into consideration the structure of the recording medium (described later) and ink characteristics (fast drying / non-fast drying). It is decided appropriately. Even in the case of a serial printer type, when the number of nozzles is 500 to 1000 nozzles or more per color and when performing double-sided printing that requires high-speed ink drying, The same consideration as described above is necessary, and the present invention can be applied to such a type.

  Next, still another feature of the ink jet recording apparatus used in the present invention will be described. FIG. 12 shows an example in which a heating unit 97 is provided in the middle of the double-sided printing conveyance path 93. As the heating unit 97, the above-described heating-type fixing device 76 (see FIG. 5 and the like), the warm air applying unit 91 (see FIG. 10 and the like), and the like are preferably used. Also in this case, it is more effective if the region heated by the heating means 97 is set to a range larger than the width of the recording medium Pa. Note that the drying of the ink by the heating unit 97 may be performed by temporarily stopping the conveyance of the recording medium Pa as described above, or may be performed by the heating unit 97 while being conveyed. Good. This is also determined appropriately in consideration of the heating capacity, the structure of the recording medium (described later), and the ink characteristics (fast drying / non-fast drying).

  In this example, the heating unit 97 is provided in the middle of the double-sided printing conveyance path 93. However, the heating unit 97 may be provided in the middle of the double-sided printing conveyance path 95, or double-sided printing paper. It may be provided on the temporary storage tray 94 and dried when temporarily stored. A plurality of heating means 97 may be provided.

  Next, features of the present invention will be described. The present invention is an invention applied to double-sided printing. In this case, it is important that high-quality image quality is obtained on both the front and back sides. In the present invention, in view of this point, the recording medium used in the present invention is symmetrical in the vertical direction as shown in FIG. 13 (recording medium sectional view).

Here, description will be given by taking paper as a typical example of a recording medium.
In the definition of orthodox paper, “paper is the one in which plant fibers are suspended in water and then sprinkled with water and tangled thinly and flatly”, but the main points are represented by grass, wood, bamboo, etc. It is an aggregate of fibers obtained by decomposing plants. The raw material of paper, regardless of whether it is Western paper or Japanese paper, is a material having a characteristic property of cellulose fiber, and paper can be obtained by processing it with a unique technique called papermaking technology to make it thin.

  Cellulose fibers used here are wood fibers having a length of 1 mm to 3 mm, a width of 20 μm to 40 μm, and a thickness of 3 μm to 6 μm in the case of paper. In general paper, about 10 to 100 are laminated in layers. . By adopting such a configuration, paper is extremely porous, and the characteristic of a smooth material having high affinity that cellulose fibers have is obtained. Japanese paper is a paper using the same cellulose fiber, but unlike wood fiber, it is a relatively elongated fiber (width 5 μm to 20 μm, length 3 mm to 7 mm) called a bast fiber, and its molecular structure is somewhat different. It has different characteristics and can be distinguished from hand-made or machine-made Japanese paper. The paper is formed by overlapping cellulose fibers in this way, and there is a gap formed by overlapping the fibers.

  The definition of paper is as described above, but paper with cellulose fibers simply overlapping is so-called base paper, and what is actually used is to increase opacity, whiteness, smoothness, air permeability, etc. Furthermore, between these fibers, filler particles having a particle diameter of about 0.2 μm to 10 μm such as talc, clay, calcium carbonate and titanium dioxide are filled in the gaps between the fibers. In FIG. 13, the base material refers to this base paper or a fiber filled with talc, clay, calcium carbonate, titanium dioxide or the like.

In addition, depending on the use of paper, further kaolin paper surface _{(Al 2 O 3 · 2SiO 2} · 2H 2 O), calcium carbonate (CaCO _3), satin white _{(3CaO · Al 2 O 3 ·} 3CaSO 4 · 31~32H 2 There is a coated paper coated with a coating liquid in which particles having a particle diameter of about 0.5 μm to 1 μm such as O) are dispersed together with a binder such as latex and starch. The particulate matter as used in the present invention refers to these materials, and as shown in the figure, it is given almost equal amounts on the upper and lower sides (front and back) of the base paper as the base material, and has the same ink absorption performance on the front and back sides. , High image quality can be obtained equally on the front and back.

The above is a description of paper. However, like an OHP sheet, the above-described kaolin (Al ₂ O ₃ .2SiO ₂ .2H ₂ O), calcium carbonate (CaCO ₃ ) is formed using a resin sheet such as a polyethylene film as a base material. ), Satin white (3CaO.Al ₂ O ₃ .3CaSO ₄ .31-32H ₂ O) and other particles having a particle diameter of about 0.5 μm to 1 μm are coated with a binder such as latex or starch. It is used by applying almost equal amount of the product to the front and back.
In any case, the point is to apply the particulate material so as to be symmetrical in the vertical direction with respect to the center line of the substrate so that the same high image quality can be obtained on the front and back sides. As shown in the recording medium sectional view), the recording medium is symmetrical in the vertical direction.

  Other types of paper include newspaper rolls, non-coated printing paper (advanced, intermediate, lower grade, thin leaf printing paper), fine coated printing paper (fine coated fine paper, fine coated printing paper), coated Industrial printing paper (art paper, coated paper, etc.), information paper (copying paper, photosensitive paper, foam paper, PPC paper, thermal paper, etc.), packaging paper (craft paper, imitation paper, etc.), sanitary paper (tissue paper, dust paper) , Toilet paper, towel paper, etc.), hybrid paper (building material base paper, laminated base paper, condenser paper, rice paper, glassine paper, etc.), corrugated paper base (liner, medium base paper, etc.).

In any case, the surface of the paper on which such cellulose fibers are overlapped is the thickness of the cellulose fibers, the gap formed by the overlap, and, in the case of the coated paper as described above, Depending on the size of the particle and the like, it is uneven when viewed microscopically. Such microscopic irregularities are very densely arranged that 400dpi~3200dpi as in the present invention, the line image quality recording is a cross-sectional area by using the very fine nozzles of 10μm ² ~600μm ² It is one of the important factors that hinders you.

  As described above, the cellulose fibers generally have a width (thickness) of about 5 μm to 40 μm, although depending on the type of paper. Paper is not usually made of fibers of such a size as it is, but generally a process of making a fiber called a beating (softening) mechanical force and making it soft in the paper manufacturing process. Therefore, the fiber size of the actually completed paper is smaller than this. Usually, the thickness or thickness of the fiber of paper manufactured through beating is about 3 μm to 6 μm.

  The present invention smoothes the surface properties of paper (base material) by applying particulate matter to the surface irregularities (normally about 5 μm to 10 μm) created by the folded state of the paper fibers produced by beating. In addition, the above-mentioned unevenness of 5 μm to 10 μm is set to 1 μm to 2 μm or less, and high quality recording is performed in a smooth state.

As the other qualities required for the recording medium of the present invention, as described above, in addition to obtaining substantially the same high image quality at the top and bottom, ink bleeding from the front and back sides does not appear on the opposite side (viewing) To the extent that it cannot be done). In the present invention, from such a viewpoint, the substrate thickness of the recording medium used in the present invention and the coating amount of the particulate matter are determined. Specifically, for example, the substrate thickness is set to 100 μm to 500 μm, and calcium carbonate (CaCO ₃ ) having a particle diameter of 1 μm as the particulate material is set to 10 g / m ^{2 to} 100 g / m ² (both sides). In addition, the base material is not purely cellulose fibers, and the filler particles as described above filled in the gaps between the fibers can reduce the thickness of the base material and can be applied to the front and back surfaces. The amount of particulate material can also be reduced.

  Next, the overall configuration of the ink jet copying machine of Embodiment 2 used for copying on the recording medium of the present invention will be described. Conventionally, what is called a copying machine generally refers to an electrophotographic system. Although such an electrophotographic system is widely used, there is a drawback that the principle is complicated and the apparatus becomes very large. On the other hand, the principle of ink jet recording is very simple. If a copying machine is configured based on this principle, a revolutionary simple copying machine that has never existed before can be realized.

  FIG. 14 shows an ink jet copier according to a second embodiment which is used for copying on a recording medium of the present invention. In FIG. 14, the ink jet copier is a document Bo placed on the document table 116. By reading the image of the surface to be copied in step S, the scanner unit 102 that sequentially forms image data for the original Bo, and the recording surface of the paper Pa as a recording medium based on the image data from the scanner unit 102 By ejecting and adhering ink, a recording unit 126 that performs a recording operation, and a paper discharge transport that is disposed below the recording unit 126 and that discharges paper Pa at a predetermined timing according to the recording operation of the recording unit 126, which is described later A transport section 134 transported to the path 136, and a paper discharge transport path for discharging the printed paper Pa ′ transported by the transport section 134 onto the paper discharge tray section 138. 36, a paper feeding / conveying unit 132 that conveys the paper Pa from the paper feeding unit 130 one by one to the recording unit 126, and a recovery processing device 124 that selectively performs recovery processing on each recording head of the recording unit 126, It is comprised including.

The scanner unit 102 includes a document scanning unit 104 that reads an image to be copied of the document Bo, and a guide rail that supports the document scanning unit 104 so as to be movable along the direction indicated by the arrow S in FIG. 14 and the opposite direction. 112 and a drive unit that reciprocates the document scanning unit 104 supported by the guide rail 112 at a predetermined speed, although not shown.
The document scanning unit 104 includes a rod array lens 106, a line sensor 110 of the same color separation as a color image sensor which is a color information reading sensor, and an exposure unit 108 as main components. Yes.

  When the document scanning unit 104 is moved and scanned in the direction of the arrow S to read the image of the document Bo on the document table 116 made of a transparent material by the driving unit, the exposure lamp in the exposure unit 108 is turned on, Reflected light from the original document Bo is guided by the rod array lens 106 and condensed on the line sensor 110. The line sensor 110 reads the color image information represented by the reflected light for each color, converts it into an electrical digital signal, and supplies it as image data to the control unit 100 in the inkjet printer unit 118 described later. Accordingly, each recording head for each color in the recording unit 126, which will be described later, discharges a liquid used for recording, for example, ink of different colors, in accordance with a drive control pulse signal based on these image data. Is done.

Sheets Pa of a predetermined standard size loaded and stored in the sheet feeding unit 130 are taken out one by one by the pickup roller unit 130RA when a driving motor (not shown) is activated, and is supplied. The paper is supplied to the paper transport unit 132.
In the copying machine based on the ink jet principle of Example 2 as well, the hot air applying means is applied, and ink drying and fixing are performed under optimum conditions. In addition, if hot air is trapped in the device, the device itself will be overheated, causing malfunction of the electrical system, or if the confidentiality in the device is too high, it will be in a high atmospheric pressure state. Ability is reduced. Accordingly, an air flow path for discharging the hot air inside the apparatus is taken into account, and an opening for efficiently releasing the hot air to the outside of the apparatus is provided.

FIG. 15 shows another example of the ink jet copying machine used for copying on the recording medium of the present invention. In FIG. 15, 201 is an ink jet recording apparatus, 202 is a document table, 203 is a scanner, 204 is a document presser, 205 is a color inkjet head unit, 126 (206a, 206b, 206c) is a paper feed cassette, 207 (207a, 207b, 207c) is a recording medium (paper), 208 is a discharge outlet after recording, and 210 (210 ₁ , 210 ₂ , 210 ₃ ) is a platen roller, 211 (211 ₁ , 211 ₂ , 211 ₃ ) is a press roller, and 212 (212 a, 212 b, 212 c) is a paper feed roller group. The recording media (207a, 207b, 207c) coming out of the paper feeding cassettes (206a, 206b, 206c) pass through the passages (paper passing paths) 209a, 209b, 209c shown by the one-dot chain lines, respectively. They are conveyed to the color ink-jet head unit 205 through a passage 209 where they join.

  FIG. 14 and FIG. 15 described above are diagrams for showing individual characteristics, respectively. The double-sided printing conveyance path 93, the double-sided printing paper temporary storage tray 94 described in FIGS. The double-sided printing conveyance path 95 and the like are not shown because the figure becomes complicated.

  The example shown in FIG. 15 shows a copier-type ink jet recording apparatus (ink jet copying machine) that has a scanner 203 and performs printing and recording by an image signal from the scanner 203, but a host computer (not shown) Needless to say, the present invention can be applied to a printer-type ink jet recording apparatus that receives and records an image signal from the printer.

  In the ink jet copying machine as shown in this example (FIG. 15), a plurality of storage members for storing the recording medium are provided (three in this example). As described above, the ink-jet copying machine used in the present invention can perform double-sided printing. The recording medium for double-sided printing is a recording medium having a substantially symmetrical structure on the front and back sides, and has a different structure from other recording media for single-sided printing. However, since such a recording member looks the same at first glance, there is often an accident in which a recording medium for single-sided printing is used by mistake in order to perform double-sided printing.

In view of this point, the ink jet copying machine used in the present invention is configured such that the plurality of recording medium accommodating members can be identified. For example, at least one of the three recording medium housing members can be distinguished from the other two by changing the shape of the other recording medium housing members, and there is almost symmetry on the front and back for double-sided printing. A recording medium having a shape structure is accommodated, and the recording medium for single-sided printing is accommodated in the other two. This identification may change the color in addition to the shape, or the surface properties (such as irregularities).
Further, in the example of FIG. 15, three are vertically stacked, but the number of stages may be determined so that, for example, double-sided printing is always at the lowest position (and its Information is registered in the CPU of this inkjet copying machine).
By doing so, the recording medium is not mistakenly used, and there is no possibility that the recording medium is wasted by mistake and the recording medium is wasted.

  Although the above description has been given with reference to an example of an ink jet copying machine, the idea of the present invention that makes it possible to distinguish a storage member that stores a recording medium for double-sided recording from other storage members is as follows. The present invention is similarly applied to an inkjet recording apparatus (inkjet printer) that performs double-sided printing and has a plurality of recording medium accommodating members and does not have a scanner function.

It is a fragmentary perspective view of the inkjet head applied to this invention. It is a figure for demonstrating the heat generating body board | substrate of the thermal inkjet applied to this invention. It is a figure for demonstrating the manufacturing process of the thermal inkjet head applied to this invention. It is a figure for demonstrating operation | movement of the thermal inkjet head applied to this invention. FIG. 4 is a diagram of a recording unit including a heat fixing device applied to the present invention. It is a figure for demonstrating the relationship between the heating means applied to this invention, and a to-be-printed part. It is a figure of the recording part containing the heat fixing apparatus of the other structure applied to this invention. It is a figure of the recording part containing the heat fixing apparatus of the other structure applied to this invention. It is a figure of the recording part containing the warm air provision means applied to this invention. It is a detailed example of the warm air provision means applied to this invention. It is a figure explaining the conveyance method of the recording medium at the time of performing double-sided printing by this invention. This is an example in which a heating device is provided when performing double-sided printing in the present invention. It is a figure explaining the recording medium used for the double-sided printing of this invention. 1 is a diagram of an ink jet copier utilizing the principles of the present invention. It is another example of the ink jet copying machine using the principle of the present invention.

Explanation of symbols

1 ... heating element substrate, 2 ... first electrode (control electrode), 3 ... second electrode (ground electrode), 4,5 ... bonding pad, 7 ... substrate, 8 ... heat storage layer (SiO _2), 9 ... heating element (HfB ₂ ), 10 ... Electrode (Al), 11 ... Protective layer (SiO ₂ ), 12 ... Electrode protective layer (Resin), 13 ... Protective layer, 14 ... Heating element part, 15 ... Electrode part, 16 ... Flow path , 17 ... discharge port, 18 ... common liquid chamber, 19 ... ceiling plate, 20 ... bonding layer, 21 ... flow path barrier, 22 ... photoresist, 23 ... photomask, 31 ... ink, 32 ... bubble, 33 ... discharge port , 34 ... flow path, 35 ... heating element substrate, 36 ... heating element, 37 ... first electrode (control electrode), 38 ... second electrode (earth electrode), 39 ... ink droplet, 40 ... transport belt, 70 ... recording , 70C, 70M, 70Y, 70B ... recording head, 72 ... head block, 72 DESCRIPTION OF SYMBOLS ... Projection part 76 ... Heating fixing device 78 ... Heat insulation device 80 ... Air layer 82 ... Reflecting plate 84 ... Halogen heater 86 ... Heating part shielding member 90 ... Heating means 91 ... Hot air giving means, 91a ... Blowing means, 91b ... Heating means, 91c ... Hot air blowing port, 92 ... Separation claw, 93 ... Double-sided printing conveyance path, 94 ... Double-sided printing paper temporary storage tray, 95 ... Double-sided printing conveyance path 96 ... Conveying rollers, 97 ... Heating means.

Claims (3)

A housing member for accommodating the recording medium, the nozzle thousands to several hundred thousand sectional area is 10μm ² ~600μm ² in arrangement density of 400Dpi～3200dpi, to cover the object to be marked Utsushihaba of said recording medium And a printing portion comprising an ink jet recording head that ejects a recording liquid onto the recording medium at a frequency of several kHz to 40 kHz per nozzle, and after printing on one surface of the recording medium The printing means and the conveyance path for conveying again to the printing unit to print the other surface, and the printing unit print so that the vertical relationship of the images on the front and back of the recording medium coincides. A recording medium for use in an ink jet recording apparatus having an enabling means, wherein the recording medium is a recording medium formed by applying a particulate material to the front and back surfaces of a substrate, the particulate material The coating, the recording medium characterized in that the irregularities following smooth surface made by said base structure material. By reading a document image placed on a document table, a scanner unit that sequentially forms image data for the document, a storage member that stores a recording medium, and thousands to several tens with an array density of 400 dpi to 3200 dpi the nozzle of thousands of cross-sectional area is 10μm ² ~600μm ^2, as well as lengthening to cover the indicia Utsushihaba of the recording medium, the recorded recording liquid at a frequency of the number per nozzle kHz~40kHz An ink jet recording head that ejects on-demand to a medium is arranged so as to eject recording liquids of a plurality of colors, and the recording liquid is ejected and adhered to the recording surface of the recording medium based on image data from the scanner unit A recording unit that performs a recording / printing operation, and transports and records the recording medium to a position opposite to the nozzle surface of the inkjet recording head. And after the printing of one surface of the recording medium, a conveying means and a conveying path for conveying again to the recording unit for printing the other surface, and the recording unit A recording medium for use in an ink jet copying machine having means for enabling printing so that the vertical relations coincide with each other, wherein the recording medium is formed by coating particulate matter on the front and back surfaces of a substrate. A recording medium, characterized in that a smooth surface equal to or less than irregularities made of the base material is formed by applying the particulate matter.   The recording medium according to claim 1, wherein the recording medium has a substantially symmetrical structure on both sides.