JP3517565B2 - Inkjet printing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet printing apparatus , and more particularly to ink fixing on a print medium.

[0002]

2. Description of the Related Art Ink jet printing apparatuses are widely used in printers, copiers and the like because of the simplicity of the mechanism in which ink droplets can be ejected directly from a print head onto a print medium for printing.

Such an ink jet printing apparatus does not require a particularly complicated post-processing mechanism after printing. For example, it does not require a relatively complicated structure such as a transfer mechanism or a heat fixing mechanism unlike an electrophotographic laser printer or a copying machine. That is, most inkjet printing apparatuses mostly rely on natural drying for fixing ink after printing.

However, since such a simple configuration is adopted for fixing the ink, the ink may bleed on the print medium, or a relatively long time may be required for drying and fixing, depending on environmental conditions such as temperature and humidity. It may be necessary or even insufficient water resistance may occur. In order to improve these problems or to further improve the print quality, a special print medium coated with a chemical or the like that reacts with the ink to promote fixing is used on the surface of the print medium, or the dots adjacent to each other are It is known that a multi-pass method is used in which a plurality of scans are formed instead of a single scan, and a different ejection port is used for each scan. According to the multi-pass method, it is possible to suppress ink bleeding, and it is possible to average variations in ejection characteristics between ejection ports. As still another method for improving the above problems, it is often practiced to adjust the permeability of ink into paper.

Further, in recent devices which are improving the printing speed, the interval between the discharged sheets is shortened by that much, and as a result, the next printed matter is overlapped before the ink is completely dried on the discharge tray, and printing is performed. There is also a risk that the printed materials themselves may be soiled by the materials rubbing or transferring with each other. This speeds up drying,
It is also known to employ heat drying to improve ink bleed. As yet another configuration,
Some use a fixing liquid that reacts with ink, and some use a water-resistant dye ink or pigment ink to increase water resistance.

[0006]

However, even with the above-mentioned conventional structure, it takes a relatively long time to obtain the water resistance of the ink. For example, with pigment ink,
It often takes several hours. For this reason, after printing, it is often within one minute even if it is naturally dried until the retransfer or scratch stain does not occur, but the water resistance is often insufficient for a while.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an ink jet printing apparatus which can obtain sufficient water resistance immediately after printing. .

[0008]

[0009]

Therefore, according to the present invention,
An inkjet printing apparatus for performing printing by ejecting ink from a print head to a print medium, wherein the print medium is conveyed in a conveyance unit that conveys the print medium and a conveyance path of the print medium by the conveyance unit. Printing means for performing printing on a print medium using a print head; and pressure rubbing means for performing pressing and rubbing operations on the print medium printed by the printing means in the transport path by the transport means. , And the pressure rubbing means,
Pressurizing member for pressurizing print medium and pressurizing member
The print medium under pressure is transported against the drag force of
It is characterized by having a transport mechanism that

[0010]

[0011]

According to the above configuration, the print medium is pressed.
The pressing member and the resistance due to the pressing force of the pressing member.
A rubbing operation accompanied by pressurization is performed on the print surface after printing by the transfer mechanism that transfers the pressurized print medium.
Cormorants so, ink components such as residual dye in the print medium surface
Forms print media, such as paper fiber gaps
It is moved to a stable position and pushed into the print medium, which makes it less soluble in water.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

[0014] <first reference embodiment> FIG. 1 is a diagram schematically showing in particular the print medium conveyance system of an inkjet printing apparatus according to one reference embodiment of the present invention.

As shown in FIG. 1, in a paper tray 1 in which papers P serving as print media are stacked, the papers P are separated and fed one by one by a separating / feeding mechanism (not shown). The fed paper P is intermittently conveyed by a predetermined amount by the paper feed roller 2 and the pinch roller 3 in synchronization with the printing operation of the print head 4.

The print head 4 is detachably attached to the carriage 5, and can similarly be supplied with ink from an ink tank (not shown) attached to the carriage 5 to eject ink. That is, the print head 4 has an electrothermal conversion element that generates thermal energy, and this thermal energy is used to generate bubbles in the ink, and the ink is ejected by the pressure of the bubbles. The carriage 5 on which the print head 4 is mounted is configured to be movable in the direction perpendicular to the plane of the drawing (main scanning direction) while being guided by the two guide shafts 5A and 5B. As a result, the carriage 5 is moved by the drive mechanism (not shown), and the print head 4 can be scanned. Paper P
A platen 6, which also functions as a heater, is provided on the opposite side of the print head 4 through which the paper P ejected with ink from the print head 4 can be heated according to the printing operation.

Paper P conveyed in synchronization with the printing operation
Are conveyed so as to pass between a pair of pressure rollers 7 provided on the downstream side of the conveyance path from the print area of the print head 4. The pair of pressure rollers 7 have respective shafts 7A.
And 7B are rotatably supported respectively, so that a driving force can be obtained from a driving mechanism (not shown) for rotation. A roller cleaner 8 is provided on one of these rollers, that is, on the side of the roller that is in contact with the print surface of the paper P, so that even if ink on the print surface adheres to the roller, it can be removed. The pressure roller 7 can be formed of a relatively hard material such as metal, and is provided with a pressure contact mechanism (not shown in FIG. 1) as will be described later with reference to FIG. The paper P can be pressed.

2 (A), 2 (B) and 2 (C) are views showing three modes of the pressure contact mechanism provided on the above-mentioned pressure roller, respectively.

The form shown in FIG. 2A is a coil spring 10.
The pulling force of 1 produces a pressing force. That is, as shown in the figure, the bearings 9A and 9B are
The supporting portion (not shown) is provided so as to be movable only in the direction of the arrow in the figure, and the respective shafts 7A and 7B of the pressure roller 7 have bearings 9A and 9B.
Each supported by. In the figure, only the shaft is shown and the illustration of the roller 7 itself is omitted. Figure 2
The same applies to (B) and FIG. 2 (C). Both ends of the coil spring 10 are bearings 9A and 9B, respectively.
Mounted on. With the above configuration, the pair of pressure rollers 7 can exert a force on each other, and when the paper P is conveyed between these rollers, a pressing force can be applied to the paper P. it can. This pressure is
It is determined in consideration of the water resistance of the print result on the paper P, which will be described later, and therefore, the tensile force of the coil spring 10 is set so as to satisfy this condition.

The above-mentioned mechanism for generating and adjusting the pressing force is preferably provided on both sides of the pressure roller 7.

In the embodiment shown in FIG. 2B, a pressing force is generated by the force exerted by the cam surface of the lever 11 on the shaft of the pressure roller. As shown in the figure, the metal lever 11 is rotatably supported by one shaft 7B of the pressure roller 7 via a bearing 9B and is engaged with the other shaft 7A of the pressure roller. It has a cam surface 11B for moving. A bearing 9A corresponding to the other shaft 7A of the pressure roller 7 is provided in the support portion so as to be movable only in the direction shown by the arrow in the figure, and the shaft 9A is supported by the bearing 9A. . A stopper plate 12 is provided on the side opposite to the side on which the cam surface 11B of the lever 11 is formed,
It is provided rotatably with respect to the shaft 12A. In the above structure, the cam surface 11B of the lever 11 is rotated while being rotated.
Is brought into contact with the bearing 9A that supports the pressure roller 7, and the stopper plate 12 is rotated counterclockwise in the figure to rotate the lever 11 in the same direction. This makes it possible to apply a force directed upward in the drawing to the shaft 7A of the pressure roller to generate a pressure force by the pressure roller. The shaft 7A and the lever 11 can be fixed at a set position by a frictional force generated between the lever 11 and the stopper plate 12. As is apparent from the above, the pressing force in this embodiment can be adjusted according to the shape of the cam surface 11B and the amount of rotation of the stopper plate 12.

In the embodiment shown in FIG. 2C, the taper portions 70A and 70B formed on the shafts 7A and 7B of the pressure roller respectively allow them and the two heights of the metal plate 13 via bearings 9A and 9B. They engage with each other and generate a pressing force on the pair of pressure rollers 7. That is, the distance between the two holes provided in the metal plate 13 and the diameter of the holes (the diameter of the hole of the bearing) are appropriately determined, and the metal plate 13 is tightly joined to the tapered portions 70A and 70B. By pushing in, an appropriate pressure can be generated in the pressure roller pair 7, 7. The metal plate 1
The fixing of No. 3 to the tapered portions 70A and 70B can be performed by the stopper plate 14 and the fixing member 15 used at the time of pushing. That is, the stopper plate 14 is rotatably supported by the shaft 1A, and the rotation allows the stopper plate 14 to push the metal plate 13 and maintain the fixed position by the frictional force. Further, the fixed position can be maintained by bringing the fixing member 15 into contact with one side of the fixed position of the metal plate 13 and fixing this member to a predetermined portion of the apparatus.

As described above, in the ink jet printing apparatus shown in FIGS. 1 and 2, the paper P printed with the ink ejected from the print head is heated to the extent that the heater 6 does not transfer the ink to the pressure roller 7. To be dried. After that, as the paper P is conveyed,
The above-mentioned pressing force is applied to the sheet P by the pressure roller. As a result, the dye or the like of the ink remaining on the surface of the paper P can be pushed into the paper and made difficult to dissolve in water. It should be noted that the roller cleaner 8 shown in FIG. 1 is provided in consideration of the case where ink is transferred to the pressure roller, and the roller cleaner is not necessarily provided when there is almost no possibility of transfer. . Further, the heater 6 does not always have to be provided depending on the speed of ink absorption on the paper P. That is, when a combination of paper and ink, which has a relatively high ink absorption speed, is used, or the time required to reach the pressure roller is relatively long depending on the transport distance and the printing method, the time for ink absorption can be saved. If possible, the heater 6 need not be provided.

On the other hand, on the contrary, when the ink is not absorbed promptly on the paper P, the pressure roller 7 may be heated so as to have a drying effect. This allows
While pressure is applied by the pressure roller, the remaining water and solvent of the ink is volatilized and dried, and the ink components such as dye remaining on the paper surface are pushed into the paper to make it more difficult to dissolve the dye in water. Therefore, it is possible to obtain a printed matter having sufficient water resistance immediately after printing.

Further, in this case, in an apparatus that does not print on thick paper, not only the portion sandwiched between the pressure rollers is heated, but as shown in FIG. By increasing the winding angle of P with respect to the roller, it is possible to lengthen the contact time with the pressure roller to facilitate thermal drying. In such a case, it is desirable to set the pressurizing temperature so that the paper does not burn, and depending on the heating time, it is within the range of 200 to 300 ° C. at the maximum when heating for 1 or 2 seconds. Further, when the print medium is a medium such as a film which is weak against heat, it goes without saying that the temperature is lowered accordingly.

Further, it is also desirable that at least a roller of the pressure roller which comes into contact with the print surface side of the paper P is subjected to a water repellent treatment so that the ink is hard to be transferred.

<Second Reference Embodiment> FIG. 4 is a schematic diagram showing a carrying system of an inkjet printing apparatus according to a second reference embodiment of the present invention.

As is apparent from the figure, in this embodiment , the pressure panel 18 is used instead of the pressure roller. Figure 5
As shown in FIG. 4, the pressure panel 18 is provided so as to be movable up and down (a mechanism therefor is not shown in FIG. 4),
As the paper P is moved downward, the paper P is pressed against the heater 6 provided as a lower panel.
Is applied. That is, the support plates 19 are fixed to both ends of the heater 6, and each of the support plates 19 supports the operation lever 20 so as to freely rotate about the shaft 19A.
The two operation levers 20 rotatably support the pressure panel 18 by their shafts 20A. As a result, it is possible to apply pressure by operating the operation lever 20 upward in the figure as indicated by the arrow in the figure.

The pressure panel 18 has a print width for one scan of the print head 4 or a length of an integral multiple of the paper feed width of the paper P in the paper transport direction. Similarly, the distance from the panel 18 is set to an integral multiple of the print width or the paper feed width. As a result, pressure is applied to each predetermined print area determined by the print width and the paper feed width, and the ink component such as the dye can be pushed into the print medium and hardly dissolved in water. This pressurizing operation can be performed by a lever driving mechanism (not shown) connected to the operation lever 20 while the paper P is stopped in synchronization with the conveyance of the paper P. In the above configuration,
For example, when printing a certain area is performed by scanning four times while changing the ink ejection ports corresponding to the area (while feeding the paper), the paper feed width is 4 times the print width of the head.
If a panel having a length three times the print width is used, the predetermined print area is 12 (= 4).
× 3) Pressurization will be performed once.

[0030] Incidentally, as in the first reference embodiment, the pressure panel 18 may have in addition an arrangement for heating and drying the sheet P, also subjected to a water repellent treatment so that the ink is not easily transferred May be.

<Third Reference Mode> In this reference mode , before the paper P reaches the pressure roller,
The distance between the head and the pressure roller is increased so that the ink on the paper dries and the ink is not transferred to the pressure roller. As shown in FIG. 6, three sets of conveyance rollers 21 and spurs 22 are provided in the paper conveyance path between the print head 4 and the pressure roller 7, so that the comparison from the head 4 to the pressure roller 7 is performed. The paper P can be conveyed over a very long distance, and the ink on the paper P can be dried during this time.

Even if a time for drying is provided by such a relatively long conveying path, if the drying is insufficient, a heater 6 may be provided as shown in FIG.

<Fourth Reference Mode> In this reference mode, as shown in FIG. 7, suction is performed from the back side of the printing surface of the paper P using a pump to promote the penetration of ink into the paper. Is. Therefore, a plurality of suction holes are provided on the surface of the platen 21, and the holes and the pump 22 are communicated with each other so that air can be sucked through these holes.

[0034] <First Embodiment> FIG. 8 (A) and (B) are respectively a side view and a top view schematically showing a sheet conveying system in the inkjet printing apparatus according to a first embodiment of the present invention is there.

In the present embodiment, not only is the print surface pressed, but the print surface is rubbed with this pressurization. As shown in FIGS. 8A and 8B, a pair of pressure panels 26 are provided on the downstream side of the print head 23 in the conveyance path of the paper P, and
Two sets of paper feed rollers 2 for surely carrying this part
4, 25 are provided. One of the pressure panels 26 can be moved up and down by a mechanism similar to that shown in FIG. As clearly shown in FIG. 8B, in this embodiment, as the print head 23, a full line type head in which ink ejection ports are arranged corresponding to the width of the paper P to be conveyed is used. ing.

In the above structure, the print head 23
The paper P is pressed by the pressure panel 26 in accordance with the printing operation by
Is transported to the position. At this time, one side of the pressure panel 26 is in a raised state, and therefore the paper P is not pressed. When the sheet P reaches the position of the sheet feeding roller 25 on the downstream side and the carrying force is obtained from this roller, the pressure is applied by the pressure panel. Then, since the paper P is continuously conveyed in this pressurized state, the rubbing operation accompanied by pressurization of the print surface is performed.

As described above, most of the ink components such as dyes and pigments on the surface of the paper are sandwiched between the pressure panels and the rubbing operation is performed, so that the paper fibers have a size of about 200 nm or less. It moves to a micro-stable position such as a gap and is adsorbed on the paper. In the case of such movement of component particles, if a large amount of movement of about 10 μm is moved, the change of the print surface due to the movement can be recognized through the naked eye, and the image on the print surface looks distorted. However, even if only a small part remaining on the surface moves by several μm, it cannot be recognized through the naked eye and does not affect the print quality. That is, in this embodiment, the pressure of the pressure panel, the transport speed, and the like are set so that such a relatively small movement occurs.

In the above setting range, the higher the pressing force, the higher the effect of adsorbing the ink component. Therefore, rather than applying pressure on a surface such as the pressure panel described above, the hard bodies 26A to 26C made of rod-shaped metal or the like as shown in FIGS. High pressure may be applied by concentrating the force. The shape of these hard bodies may be any shape as long as a high pressure can be applied and there is no problem in paper feeding. Further, the back side of the paper P may be a panel as shown in FIG. 8 or a roller shape as shown in FIG.

Further, the back surface of the paper may be rubbed similarly with a rod-shaped hard body. Alternatively, the rubbing operation may be performed on the surface of the paper by rotating the roller at a speed different from the paper feeding speed.

Second Embodiment As shown in FIG. 10, a heater 28 and a reflecting plate 27 for reflecting the heat may be provided to dry the print surface of the paper P. Further, when pressure is applied to the paper P by the roller, unless the ink remains as a liquid that is washed away by the pressure, the cleaner 8 is attached to the roller as shown in FIG. The generated ink can be removed, and thus, the pressure can be applied in a semi-dry state of the ink that causes retransfer.

[0041]

As described above, according to the present invention,
Pressurizing member for pressurizing print medium and pressurizing member
The print medium under pressure is transported against the drag force of
Accompanied pressurized to the print surface after printing by that transport mechanism
Ink components such as dyes remaining on the surface of the print medium form the print medium because the rubbing operation is performed.
It is moved to a stable position such as a gap between paper fibers and pushed into the print medium, which makes it difficult to dissolve in water.

As a result, it is possible to obtain a printed matter having sufficient water resistance immediately after printing.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a carrying system of an inkjet printing apparatus according to a first reference embodiment of the present invention.

2 (A), (B) and (C) are respectively the same as in FIG.
FIG. 6 is a diagram showing a mechanism for generating a pressing force of the pressure roller shown in FIG.

FIG. 3 is a diagram schematically showing a transport system of an inkjet printing apparatus according to a modified example of the first reference embodiment.

FIG. 4 is a diagram schematically showing a transport system of an inkjet printing apparatus according to a second reference embodiment of the present invention.

5 is a schematic perspective view showing a mechanism for moving the pressure panel shown in FIG. 4 up and down.

6 is a diagram schematically showing a conveyance system of an inkjet printing apparatus according to a third referential embodiment of the present invention.

FIG. 7 is a diagram schematically showing a transport system of an inkjet printing apparatus according to a fourth reference embodiment of the present invention.

8A and 8B are a side view and a top view, respectively, schematically showing a transport system of the inkjet printing apparatus according to the first embodiment of the present invention.

9 (A), (B) and (C) are diagrams showing configurations of pressurization and rubbing according to a modification of the first embodiment, respectively.

FIG. 10 is a diagram schematically showing a carrying system of an inkjet printing apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

1 paper tray 2 Paper feed roller 3 pinch rollers 4,23 print head 5 carriage 6 heater 7 Pressure roller 7A, 7B axis 10 coil spring 11 lever 12 Stopper 13 Metal plate 16 guides 17 Output tray 18 Pressure panel 22 pumps 27 Reflector 28 Radiant heater

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-63264 (JP, A) JP-A-5-147206 (JP, A) JP-A-7-323531 (JP, A) JP-A-6- 115060 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/01 B41J 29/00

Claims (5)

(57) [Claims] 1. An inkjet printing apparatus for performing printing by using a print head and ejecting ink from the print head onto a print medium, wherein the print medium is transported by a transport means and a transport path of the print medium by the transport means. In the printing means, the printing means prints on the conveyed print medium by using the print head, and the printing medium printed by the printing means is pressed and rubbed in the conveying path by the conveying means. Pressure rubbing means, wherein the pressure rubbing means conveys the print medium to be pressed against a pressure member for pressurizing the print medium and a drag force of the pressure member. An inkjet printing apparatus comprising: 2. The inkjet printing apparatus according to claim 1, wherein the pressing member includes a panel-shaped member. 3. The ink jet printing apparatus according to claim 1, wherein the pressing member has a roller that rotates at a surface speed different from a transportation speed of the transportation mechanism. 4. The inkjet printing apparatus according to claim 1, wherein the pressing member includes a rod-shaped member. 5. A heating means for heating the printed printing medium is further provided.
5. The inkjet printing apparatus according to any one of 1 to 4.