JP2006205566A - Inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively realize an efficient reduction in fine mist produced except for an ejected main ink droplet, without upsizing an inkjet printer for forming an image by ejecting ink and the like onto a recording medium. <P>SOLUTION: A suction port for sucking in the ink mist is connected to a pump by a tube; a cap is connected to the pump by the tube; and a switching valve enables switching to be performed between the suction of the mist and a head recovery operation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus that forms an image by ejecting ink onto a recording medium from an ink ejection port formed in a print head.

  Inkjet printing methods are used in printers, copiers, facsimiles, and the like for reasons such as low noise, low running costs, easy size reduction, and easy colorization.

  However, the inkjet printing method has the following specific problems.

  1) Since ink droplets are ejected from an inkjet head onto a recording medium such as paper or an OHP film for printing, fine ink droplets (mist) generated in addition to the ejected main ink droplets and ink droplets ejected onto the recording medium Ink adheres to the ink discharge port surface of the inkjet head due to rebounding, and a large amount of the ink collects around the ink discharge port. If foreign matter such as paper dust adheres to the ink discharge port, the ink discharge is hindered. This causes problems such as the occurrence of twisting in the direction of discharge and the inability to discharge ink droplets.

  2) If the inkjet head is not ejected accurately for a long time when it is not printed, the ink in the nozzle that is the ink ejection port will evaporate and dry, and the thickened and solidified ink will clog in the nozzle and become misaligned. Or discharge failure such as non-ejection.

  The ink jet recording apparatus generally includes the following recovery means as means for solving the problems 1) and 2) described above. The ink-jet head is capped during non-printing to prevent the ink in the nozzles of the ink-jet head from evaporating and drying to thicken and stick.

  Also, in the unlikely event that a thickening / adhesion causes discharge failure, or foreign matter that cannot be removed by the blade adheres to the discharge port surface, the thickened ink in the nozzle is connected with a suction pump connected to the cap. A recovery process is performed to recover the normal discharge. The discharged ink is absorbed by a waste ink absorber provided in the apparatus main body through a tube or the like provided on the downstream side of the suction pump.

  In recent years, inkjet recording apparatuses aim to improve the image quality of images recorded on recording media and reduce the size of ink droplets (dots) ejected from the nozzles of an inkjet head as much as possible in order to reduce graininess. Is desired. Therefore, by reducing each nozzle diameter of the ink discharge port of the ink jet head, the amount of fine mist generated other than the main ink droplet to be discharged tends to be scattered more than before.

  Furthermore, in an ink jet recording apparatus that can print with a margin of the edge of the recording medium being zero (see, for example, Patent Document 1), the scanning range of the carriage on which the ink jet head is mounted extends to a position outside the left and right ends of the recording medium. There is a tendency that a larger amount of mist is scattered by moving and ejecting ink droplets or ejecting ink droplets from the upper and lower ends of the recording medium.

  In addition to adversely affecting the ink jet head as described above, the mist adheres to the recording medium conveyance mechanism and parts around the conveyance path, and may contaminate the recording medium and cause malfunction. Furthermore, there is a possibility that mist leaks from a gap in the casing of the ink jet recording apparatus and contaminates the periphery of a desk or the like on which the ink jet recording apparatus is placed.

Therefore, a technique for mounting a member or mechanism for absorbing mist and suppressing scattering on an ink jet head or a carriage (see, for example, Patent Document 2), a fan is provided in the casing, and the scattered mist is collected at a specific location. There are technologies (for example, see Patent Document 3).
Japanese Patent Laid-Open No. 10-337886 (FIG. 2, paragraph [0014]) Japanese Patent Laying-Open No. 2002-361902 (FIG. 1, paragraph [0017]) JP-A-11-138780

  However, since the carriage has a heavy weight in an apparatus in which the ink jet head of the above-described conventional example is provided with a member or mechanism for suppressing scatter by suppressing mist, a motor with high output must be used, This increases the size and cost of the members and mechanisms, and it is difficult to employ them in low-cost inkjet recording apparatuses. The apparatus provided with the conventional fan may also increase the size and cost of the apparatus by the amount of the fan.

  An object of the present invention is to inexpensively reduce fine mist generated in addition to discharged main ink droplets in an inkjet printing apparatus that forms an image by discharging ink and the like onto a recording medium. It is to be realized without increasing the size.

  In order to achieve the above object, a configuration according to the present invention includes a suction port for sucking ink mist, wherein the suction port and the pump are connected by a tube, and the cap and the pump are connected by a tube.

  It is also desirable that a switching valve is provided between the suction port and the pump, and the cap and the switching valve are also connected so that the operation of the pump can be switched between the suction port and the cap.

  In addition, the hole in the platen having holes for borderless printing and preliminary discharge functions as the function of the suction port, or the cap itself also functions as the function of the suction port.

  It is also desirable that the suction pressure of the pump be variable depending on the recording medium, printing position, printing mode, ink amount, ink type, and ink nozzle diameter.

  That is, the technical contents of the present invention can solve the above-described problems by including the following configuration.

  (1) An inkjet recording apparatus comprising a head for ejecting ink droplets, a pump capable of generating negative pressure, and a cap for capping the head, and is located in the vicinity of the head, A suction port for sucking ink mist formed other than the main ink droplets of the ink ejected from the head; the suction port and the pump are connected by a tube; and the cap and the pump are connected by a tube And an ink jet recording apparatus that functions as an ejection recovery apparatus.

  According to the present invention, in an ink jet printing apparatus that forms an image by ejecting ink and the like onto a recording medium, it is inexpensive to efficiently reduce fine mist generated in addition to the ejected main ink droplets. This is possible without increasing the size.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

(First embodiment)
A first embodiment of the recording apparatus of the present invention will be described.

  FIG. 1 is a schematic front view showing an embodiment of an ink jet recording apparatus according to the present invention, and FIG. 2 is a schematic top view showing the configuration of some of the components. In FIG. 2, members unnecessary for explanation such as a paper conveyance system and electric parts are not shown.

  1 and 2, the printing unit 2 includes ink tanks 3B, 3Y, 3M, and 3C, a carriage 4, and an ink jet head (head) 5 below, and further outputs signals for driving the head. A connector (not shown) for receiving is provided. The carriage 4 accommodates the ink tanks 3B, 3Y, 3M, and 3C, is detachably mounted, and is provided with a connector holder (not shown) for transmitting signals for driving the ink jet head. The inkjet head 5 is electrically connected.

  Each of the heads 5 includes, for example, 300 ejection openings, and each of the ejection openings ejects an ink amount of, for example, 40 ng. Each of the tanks 3B, 3Y, 3M, and 3C is connected to the head 5 via a connection unit (not shown) and supplies ink. The guide shaft 10 extends in the main scanning direction of the carriage 4 and is supported by the side chassis 8 and 9 so as to slidably support the carriage 4. The driving belt 6 transmits the driving force of the driving motor 7 for reciprocating the carriage 4 to the carriage 4.

  Reference numerals 22, 23, 24, and 25 denote transport rollers for holding and transporting the recording medium. (24 is a spur with a sharp tip that does not rub the printed surface.) Two pairs of transport rollers 22, 23 and 24, 25 are arranged before and after the print position by the head 5. The recording medium P is conveyed in a state of being pressed against the platen 11 that regulates the recording surface to be flat. At this time, the head portion 5 mounted on the carriage 4 protrudes downward from the carriage 4 and is positioned between the print medium transport rollers 22 and 24, and the ink discharge port forming surface (nozzle surface) of the head 5 is the platen 11. It faces the recording medium 11 pressed against the guide rib 11c in parallel.

  On the platen 11, ink droplets ejected from the head 5 when printing out from the end of the recording medium P (hereinafter referred to as borderless printing) in order to make the margins at the upper, lower, left and right edges of the recording medium P zero. A sponge 19 that has a receiving hole 11a and catches ink that is discharged and floats in the hole 11a is embedded in the hole 11a. The sponge 19 is a coarse-grained sponge with good air permeability, and air flows easily. The platen 11 further has a preliminary outlet 11b, and a sponge 18 similar to the sponge 19 is embedded in the same manner. The ink collected by the sponges 18 and 19 flows through the ink flow path 20 below the hole 11a to the lowermost collecting portion 20s.

  For the maintenance of the head 5 (head 5 recovery, cleaning, capping, etc.), a cap 12 is provided, and the recording head 5 can be raised and lowered in the direction of ejecting ink. When the recording head 5 is moved directly above the cap 12 (this position is referred to as a home position), it rises to seal the nozzle surface of the head 5 and the ink in the ejection openings of the head 5 evaporates and increases. It prevents sticking and sticking to cause discharge failure.

  A pump 16 connected to the switching valve 15 and a tube is provided below the platen 11. The switching valve 15 is connected to the collecting unit 20 s below the platen hole 11 a and the tube 13. . Further, the switching valve 15 is also connected to the cap 12 via the tube 14.

  When the switching valve 15 is open with the tube 14, the pump 16 generates a negative pressure during a suction recovery process performed by joining the cap 12 and the head 5 in the event that the head 5 becomes defective in discharge. Let The waste liquid after the suction recovery process is absorbed and stored in the waste ink absorber 17 through the tube 14 and the pump 16.

  Similarly, when the switching valve 15 is opened with the tube 13, the pump 16 can make the vicinity of the hole 11 a of the platen 11 negative pressure. When ink is ejected from the head 5 and the mist is floating at that time, the mist is sucked up and absorbed and stored in the waste ink absorber 17 through the tube 13 and the pump 16.

  The pump 16 can vary the suction pressure, and varies the negative pressure generated by the direction in which the valve 15 is opened, the amount of mist, and the like.

  Next, the operation during borderless printing when this embodiment is used will be described. FIG. 3 is a schematic sectional view of this embodiment.

  The PE sensor 27 detects the leading edge and the trailing edge of the recording medium when the leading edge of the recording medium P fed from the arrow Q direction rotates the PE sensor lever 26. After detecting the leading edge of the recording medium, the recording medium is conveyed by the conveying roller pairs 22 and 23 to a position shown in FIG. During this period from the print command by the user, the head 5 is positioned immediately above the preliminary discharge port 11b of the platen, and by performing empty printing in advance toward the preliminary discharge port before printing on the recording medium, from the first printing on the recording medium. I try not to go out. From this time, the opening of the switching valve 15 is set to 13, and the operation of the pump 16 is started.

  FIG. 4 is a schematic top view showing the platen 11 during borderless printing. In FIG. 4, a hatched portion 28 indicates a print area ejected by the recording head 5. The ink droplets that do not overlap the recording medium P and the floating mist that is not the main ink droplets are absorbed and stored in the waste ink absorber 17 through the sponge 19 by the negative pressure near the hole 11 a generated by the pump 16. When there is a recording medium at the position shown in FIG. 4, since most of the mist or the protruding ink is printed, the pump 16 is set to the maximum suction pressure at this time. During printing, the pump 16 always operates and continues to generate negative pressure near the platen hole 11a.

  FIG. 5 shows a state where a predetermined amount of the recording medium P is conveyed in the direction of arrow Q by the conveying roller pairs 22, 23, 24, and 25 from the state of FIG. Since the mist and the protruding ink are less in the position of the recording medium P in the position of FIG. 5 than in the position of FIG. 5, the pump 16 may be less than the suction pressure in FIG. 4, and thus reducing power consumption and noise by reducing the suction pressure. be able to.

  6 shows a state in which the recording medium P is further conveyed in the direction of arrow Q by the conveying roller pairs 22, 23, 24, and 25 from the state of FIG. 5, and the rear end of the recording medium P is positioned on the hole 11a. In this case as well, as in FIG. 4, since most of the mist or the protruding ink is printed, the pump 16 is set to the maximum suction pressure.

  In addition, since mist is generated even in normal printing, which is not borderless printing, it is effective to operate the pump 16.

  In addition, it is possible to reduce power consumption and noise by changing the suction pressure of the pump 16 between printing with a large number of nozzles and printing with a large discharge amount, and printing with a small number of nozzles and printing with low discharge. .

  In addition, when ink with a large amount of mist and an ink with a small amount of mist are mounted depending on colors, it is possible to reduce power consumption and noise by reducing the suction pressure of the pump 16 during printing with ink with a small amount of mist.

  In addition, when a head with different nozzle diameters is installed in which the nozzle diameter is not the same for all nozzles, the suction pressure of the pump 16 may be reduced during printing using large nozzles. Can be suppressed.

  Further, when using a recording medium with a small amount of mist, reducing the suction pressure of the pump 16 depending on the type of the recording medium can also reduce power consumption and noise.

(Second Embodiment)
FIG. 6 is a schematic top view showing the configuration of the present embodiment, but the tubes 13 and 14, the valve 15, the pump 16, and the absorber 17 are shown in an accurate position because of a schematic arrangement for explanation. Not. In this embodiment, the lowermost collecting portion 20s of the ink flow path 20 of the platen 11a according to the first embodiment is not connected to the pump, and the ink of 11a is transferred to the waste ink absorber 17 at the bottom. It falls under its own weight.

  FIG. 7 is a schematic cross-sectional top view of the spur holder 21 that supports the spur 24, but the tubes 13 and 14, the valve 15, the pump 16, and the absorber 17 are shown in an accurate position for the schematic arrangement for explanation. Absent. The spur holder 21 has a discharge port 30 and is connected to the pump 16 by a tube 13 via a switching valve 15. A suction port 31 is provided between each spur 24, and mist scattered from the head 5 during printing through the collection unit 29 can be sucked by the pump 16.

  Other configurations and operations are the same as those in the first embodiment, and are omitted.

(Third embodiment)
The collecting unit 20s at the lowermost end of the ink flow path 20 of the platen 11a according to the first embodiment and both the ink flow path 29 and the tube coupling part 30 of the spur base 21 according to the second embodiment are provided. The provided form is still effective.

(Fourth embodiment)
The collecting unit 20s at the lowermost end of the ink flow path 20 of the platen 11a according to the first embodiment and both the ink flow path 29 and the tube coupling part 30 of the spur base 21 according to the second embodiment are provided. Even if the mist is absorbed only by the suction of the cap by the pump 16 during printing, the effect is less than the above three forms, but it is effective. In this case, in order to easily collect the mist on the side opposite to the cap (side chassis 8 side), a vent hole is provided in the side chassis 8 to create an air flow in the housing in the direction from the side chassis 8 to the side chassis 9. And more effective.

1 is a schematic configuration front view showing a main part of an ink jet recording apparatus according to a first embodiment of the present invention. 1 is a schematic top view illustrating a platen of an ink jet recording apparatus according to a first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic right side view of a configuration showing a main part of an ink jet recording apparatus according to a first embodiment of the present invention. FIG. 3 is a schematic top view showing the position of the platen and recording medium during printing and the printing range of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic top view showing the position of the platen and recording medium during printing and the printing range of the ink jet recording apparatus according to the first embodiment of the present invention. It is a typical structure schematic top view which shows the principal part of the inkjet recording device which is the 2nd Embodiment of this invention. It is a typical composition schematic sectional view showing the structure of the platen of the ink jet recording device which is the 2nd embodiment of the present invention.

Explanation of symbols

3B, 3Y, 3M, 3C Ink tank 4 Carriage 5 Head 6 Belt 7 Motor 10 Guide shaft 11 Platen 11a, 11b Platen hole 12 Cap 13, 14 Tube 15 Valve 16 Pump 17 Waste ink absorber 18, 19 Sponge 20 Ink flow path 21 spur holders 22 and 23 transport roller pair 24 spur 25 paper discharge roller 26 PE lever 27 PE sensor 28 print area 29 ink collecting unit 30 discharge port 31 suction port

Claims (11)

An inkjet recording apparatus comprising: a head for ejecting ink droplets; a pump capable of generating negative pressure; and a cap for capping the head;
A suction port for sucking ink mist formed in the vicinity of the head and other than the main ink droplets of ink ejected from the head, wherein the suction port and the pump are connected by a pipe; and An ink jet recording apparatus, wherein a cap and the pump are connected by a pipe and function as a discharge recovery device.   A switching valve is provided between the suction port and the pump, and the cap and the switching valve are connected. The switching valve generates a negative pressure at the suction port, and a negative pressure is applied to the cap. The ink jet recording apparatus according to claim 1, wherein switching between generation and generation is possible.   A platen provided with a hole for receiving ink droplets ejected from the head at a position opposed to the head and the recording medium, and the hole for receiving the ink droplets of the platen has a function of the suction port; 3. The ink jet recording apparatus according to claim 1, wherein a flow path of a hole for receiving the ink droplet of the platen and the pump are connected by a pipe.   The inkjet recording apparatus according to claim 1, wherein the cap has a function of the suction port.   The ink jet recording apparatus according to claim 1, wherein the suction pressure of the pump is variable.   6. The ink jet recording apparatus according to claim 5, wherein the pump variably controls the suction pressure according to the type of the recording medium.   The ink jet recording apparatus according to claim 5, wherein the pump variably controls the suction pressure according to the position of the head on the recording medium.   8. The ink jet recording apparatus according to claim 5, wherein the pump variably controls the suction pressure in accordance with a recording mode of ejection by the head.   The ink jet recording apparatus according to claim 5, wherein the pump variably controls the suction pressure according to the amount of ink ejected by the head.   The ink jet recording apparatus according to claim 5, wherein the pump variably controls the suction pressure according to the type of ink ejected by the head.   The inkjet recording apparatus according to claim 5, wherein the pump variably controls the suction pressure according to the size of the ejection port of the head.

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