JP2007261026A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device which can eliminate ink contamination in recording equipment by securely accommodating a predischarged ink in a spent ink tank even in the case that the predischarged ink is accumulated in edge discharge receivers. <P>SOLUTION: The edge discharge receivers 18 are installed in a plurality of positions corresponding to edges on both sides of a recording medium S of a platen 3 for supporting the recording medium S. In addition, the spent ink tank 16 loaded with an ink absorber 19 is arranged under the platen 3, and an independent space 25 communicating with each of the edge discharge receivers 18 is formed in the spent ink tank 16. Thus, the ink discharged by the predischarging operation not intended for recording from a recording head is received by the edge discharge receivers 18 and accommodated in the space. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that records an image on a recording medium by ejecting ink from a recording head based on image information, and more particularly to an ink jet recording apparatus that improves an ink recovery method for a waste ink tank.

  The recording apparatus is widely used as an image data output apparatus in an image forming apparatus having functions such as a printer, a copier, and a facsimile, or a composite electronic apparatus including a computer and a word processor, a workstation, and the like. These recording apparatuses are configured to form images (including characters and symbols) on recording media such as paper, cloth, plastic sheets, and OHP sheets based on image information. There are two types of recording systems in this recording apparatus: a serial type and a line type. The serial type is a system in which an image is recorded while alternately repeating main scanning for moving the recording head along the recording sheet and sub-scanning for feeding the recording sheet at a predetermined pitch. On the other hand, in the line type, by using a long recording head extending in the width direction of the recording sheet, an image is recorded only by paper feeding (sub scanning) of the recording sheet while recording one line at a time. It is a method. The recording apparatus can be classified into an inkjet recording apparatus, a thermal transfer recording apparatus, a laser recording apparatus, a thermal recording apparatus, a wire dot recording apparatus, and the like according to a recording method.

  Among them, the ink jet recording apparatus performs recording by ejecting ink from a fine ejection port of the recording head, and includes a recovery processing apparatus for maintaining and recovering the ink ejection performance of the recording head. The recovery process includes, for example, a wiping process for removing thickened ink and dust adhering to the ejection surface, and ink that contains thickened ink and bubbles by a suction pump in a capping state in which the cap is in close contact with the recording head. This is performed by a suction recovery process for sucking the liquid from the discharge port. The ink (waste ink) discharged by the suction recovery process is guided to a waste ink tank. The waste ink tank usually includes a casing for containing ink and an absorber filled in the casing for absorbing and holding ink. Such a waste ink tank is replaced with a new tank by notifying the user when the ink holding amount of the absorber reaches the limit.

  In addition, capping and preliminary ejection are also performed in an inkjet recording apparatus that records fine and clear images by ejecting fine ink droplets. Capping is to prevent evaporation and drying of ink due to outside air by covering the ejection port of the recording head with a cap. In the preliminary ejection, in order to prevent the ejection port from being clogged with thickened ink or the like, ink that is not intended for recording is ejected from each ejection port at regular intervals. In order to perform this preliminary discharge, a preliminary discharge receiver for receiving the discharged ink, a waste ink tank for storing the ink received by the preliminary discharge receiver, and the like are necessary.

  FIG. 5 is a partial plan view showing a preliminary discharge receiver and a waste ink tank of a conventional ink jet recording apparatus. In FIG. 5, preliminary discharge receptacles are provided on both sides of the platen 3 for guiding and supporting a recording medium such as recording paper to be recorded, that is, on the reference side where the recovery unit 11 is installed and the non-reference side opposite to the reference side. 17 is disposed. However, when preliminary ejection is performed in such a configuration, it is necessary to move the recording head to one of the preliminary ejection receptacles. For this reason, the recording speed is almost constant regardless of the size of the recording medium, and it is difficult to improve the recording speed.

  On the other hand, in the ink jet recording apparatus, an edge discharge receiver 18 for receiving ink discharged at a position protruding from the edge is provided at the edge of the recording medium S when performing edgeless recording. The edge discharge receptacles 18 are provided in at least two places including both side edges of the recording medium. When recording on recording media of different sizes, the edge discharge receivers 18 are provided in three or more places according to the number of types of sizes. become. Therefore, in order to improve the recording speed of a recording medium of a small size, there is a method of performing preliminary discharge using such an edge discharge receiver 18.

  In such preliminary ejection, there is a problem that a part of the ejected ink is scattered in a mist and ink mist is generated. The generated ink mist is wound up inside the recording apparatus by a negative pressure generated rearward in the moving direction as the recording head or carriage moves. The ink mist thus wound up adheres to components and members inside the recording apparatus. The attached ink mist stains the user's hand accessing the internal parts and members by opening the cover, adheres to the sliding part of the carriage, and adheres to the encoder and encoder sensor for positioning the carriage. . If it adheres to the encoder or encoder sensor, it may cause a malfunction of the recording apparatus.

In order to eliminate these inconveniences caused by ink mist, for example, Patent Document 1 discloses the use of a fan unit that combines a duct and a fan for sucking ink mist that discharges air inside the recording apparatus to the outside.
JP 2001-191557 A

  However, in recent years, pigment ink has been adopted for both black ink and color ink from the viewpoint of improving the color developability of black recording and improving the color reproducibility of color recording. In the preliminary ejection in which the pigment ink is idly ejected from the recording head, the ejected ink is easily dried and solidified. For this reason, there is a possibility that the pre-discharged ink adheres in the flow path from the pre-discharge receiver to the waste ink tank and closes the flow path. When the flow path is blocked, waste ink overflows and may contaminate the inside of the recording apparatus.

  FIG. 6 is a longitudinal sectional view in a direction intersecting the recording medium conveyance direction of the fan unit and the waste ink tank of the conventional ink jet recording apparatus. In FIG. 6, each edge discharge receptacle 18 is maintained at a negative pressure in order to prevent ink mist by preliminary discharge from spreading to the inside of the recording apparatus and contaminating parts and members. However, each of the edge discharge receptacles 18 is not an independent space, but communicates with a common platen duct 21. For this reason, the ink preliminarily ejected at each edge ejection receptacle 18 is accumulated in the platen duct 21 and may be fixed as a deposit. In FIG. 6, edge discharge receptacles 18 are arranged at three positions A, B, and C of the platen duct 21, and the ink discharged to each edge discharge receptacle is recovered by a suction fan (not shown). The ink is sucked into the waste ink tank 16 of the unit 11. Therefore, if the pre-discharged ink is accumulated at the position C, for example, in the platen duct 21, then the ink discharged from the position A or B is blocked at the position C and reaches the waste ink tank 16. It may overflow without being guided. Overflowing waste ink causes contamination inside the recording apparatus.

  The present invention has been made in view of such technical problems. It is an object of the present invention to eliminate ink contamination inside a recording apparatus by reliably storing preliminarily ejected ink in a waste ink tank even when preliminarily ejected ink accumulates on an edge ejection receptacle. An ink jet recording apparatus is provided.

  The present invention relates to an ink jet recording apparatus that records an image by ejecting ink from a recording head onto a recording medium. Edge discharge receptacles are provided at a plurality of positions corresponding to the edges on both sides of the recording medium of the platen for supporting the recording medium at positions facing the recording head. A waste ink tank loaded with an ink absorber is disposed below the platen, and an independent space communicating with each of the edge discharge receptacles is formed inside the waste ink tank. Ink discharged from the recording head by preliminary ejection not intended for recording is received at the edge, and the ink is accommodated in the space.

  According to the present invention, even if ink to be preliminarily ejected accumulates on the edge ejection receptacle, ink contamination inside the recording apparatus can be eliminated by reliably storing the preliminarily ejected ink in the waste ink tank. An ink jet recording apparatus is provided.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 1 is a perspective view showing an embodiment of an ink jet recording apparatus according to the present invention. FIG. 2 is a plan view showing a preliminary discharge recovery mechanism provided on the platen of the ink jet recording apparatus of FIG. In FIG. 1, a recording medium S made of a recording sheet such as recording paper or a plastic sheet is sandwiched between a conveying roller 1 and a pinch roller 2 that rotates following the conveying roller 1. It is conveyed in the direction of arrow A in the figure while being guided and supported. The platen 3 supports the recording medium S when an image is formed by the recording head (inkjet head) 4, and the recording surface facing the discharge surface (surface on which the discharge ports are arranged) of the recording head 4. The distance from the surface of the medium S is maintained at a constant or predetermined distance.

  On the platen 3, a pressing member 14 is provided for suppressing the lifting of the end portion of the recording medium in the direction crossing the transport direction (arrow A). The plurality of pinch rollers 2 are rotatably held by a pinch roller holder (not shown). A carriage 7 on which the recording head 4 is mounted is guided and supported so as to reciprocate along the two guide rails 5 and 6. The recording head 4 is positioned and mounted on the carriage 7 so as to be detachable with an attitude of ejecting ink toward the recording medium S. The carriage 7 is reciprocally driven in a direction (main scanning direction) intersecting the recording medium conveyance direction (arrow A direction, sub-scanning direction) by a driving unit such as a motor (not shown) during recording. In particular, the recording head 4 includes means (for example, a heating resistance element) that generates thermal energy as energy used for ink ejection, and causes ink state change (film boiling) by the thermal energy. The droplet is discharged from the discharge port. The recording head may be a system using other energy generating means such as vibration energy in addition to the thermal energy system.

  A plurality of ejection port arrays for ejecting inks of different colors are provided on the ejection surface of the recording head 4. Each discharge port array is configured by arranging a plurality of discharge ports at a predetermined pitch. A plurality of independent ink tanks 8 are detachably mounted on the tank mounting unit 9 corresponding to the color of ink used in the recording head 4. The tank mounting unit 9 and the recording head 4 are connected by a plurality of supply tubes 10 corresponding to ink colors. By mounting each ink tank 8 in the tank mounting unit 9, the ink stored in each ink tank is independently supplied to each ejection port array (liquid chamber leading to each ejection port array) of the recording head 4. can do. The recording medium S conveyed onto the platen 3 is sandwiched between the discharge roller 12 and a spur 13 that is driven to rotate after the image is recorded, and is discharged from the platen 3 by the rotation of the discharge roller 12. .

  A recovery unit 11 is disposed in a predetermined position (for example, home position) in a region within the reciprocal movement range of the recording head 4 and outside the conveyance range of the recording medium S. The recovery unit 11 is for maintaining and recovering the ink ejection performance of the recording head 4. The recovery unit includes, for example, cap means for capping the ejection port by being brought into close contact with the ejection surface of the recording head 4. Furthermore, a suction unit for forcibly sucking ink from the ejection port in a state where the recording head is capped, and a wiper unit including a flexible blade for wiping the dirt on the ejection surface of the recording head 4 are provided. ing. A waste ink tank 16 for storing ink (waste ink) sucked by the suction means is disposed below the platen 3. The waste ink tank 16 can be replaced by the user side being attached and detached in the direction of the arrow.

  1 and 2, when borderless recording is performed, recording is performed by ejecting ink to a range including a region outside the recording medium at the side edge of the recording medium. An edge discharge receiver 18 is provided on the platen 3 in order to receive ink discharged to a region protruding from the recording medium. The edge discharge receiver 18 needs to be arranged for each size of the recording medium to be used, and is provided on the platen 3 for each size. Further, since the left and right edges of the recording medium are recorded without margins on the platen 3, at least two edge discharge receivers 18 are required, and usually three or more are provided. FIG. 2 shows a state in which borderless recording is performed on the recording medium S using two edge discharge receptacles 18 on the right side of the drawing. Here, a state when two-line borderless recording indicated by hatching (recording pattern) on the recording medium S is completed is shown. In the present embodiment, a detachable waste ink tank 16 is disposed on the lower side of the platen 3, and the ink discharged (discharged) from the recording head 4 to the edge discharge receiver 18 is accommodated in the waste ink tank 16. Is done.

  FIG. 3 is a longitudinal sectional view of the preliminary discharge recovery mechanism provided in the platen of the ink jet recording apparatus according to the embodiment of the present invention as viewed from the recording medium conveyance direction. 4 is a partial cross-sectional perspective view showing a part of the structure of the edge discharge receiver in FIG. 2 to 4, the waste ink tank 16 is loaded with an ink absorber 19 for absorbing and holding the introduced ink. As the ink absorber 19, a member having excellent ink absorbability such as a porous material or a fiber material is used. In the present embodiment, as shown in FIG. 2, the suction means (suction pump) 28 of the recovery unit 11 is connected by a waste ink tank tube 23. The recovery unit 11 includes a cap unit for capping the ejection port of the recording head, a suction pump as a suction unit connected to the cap unit, and a foreign substance such as ink adhering to the ejection surface of the recording head. Wiper means and the like are provided.

  As one of the recovery processes of the recording head 4, suction recovery is performed by refreshing the ink in the discharge port by operating the suction unit 28 connected to the cap unit while the discharge port is capped to suck the ink from the discharge port. Processing is performed. The ink sucked and discharged from the discharge port in this suction recovery is discharged through the suction pump 28 and the waste ink tank tube 23. Thus, the ink discharged from the recovery unit 11 is also guided into the waste ink tank 16 through the waste ink tube 23 and is absorbed and held by the ink absorber 19.

  2 to 4, a space 25 communicating with each of the plurality of edge discharge receivers 18 arranged on the platen 3 is formed inside the waste ink tank 16. Each space 25 is formed adjacent to a corresponding edge discharge receptacle 18, and each edge discharge receptacle 18 communicates with the corresponding space 25 individually through an opening 26 formed in the upper surface of the waste ink tank 16. Yes. As shown in the figure, each space 25 communicates with the edge discharge receiver 18, but the other inner surface is formed by the inner surface of the waste ink tank and the surface of the ink absorber and becomes a sealed independent space. Yes. Each edge discharge receptacle 18 is provided with a suction port 22. This suction port is connected to the suction fan 30 via the air flow path 27. Therefore, each edge discharge receiver 18 can be maintained in a negative pressure state by being sucked by the suction fan 30 through the suction port 22.

  In the ink jet recording apparatus, as one of the recovery processes of the recording head, preliminary ejection for ejecting ink not intended for recording from the ejection port is performed. This preliminary ejection is a process for refreshing the ink in the ejection ports, and is normally performed before and after the recording operation, but may be performed at regular intervals during the recording operation. When performing preliminary ejection, ink is ejected from the recording head 4 toward one of the edge ejection receptacles 18. That is, the edge discharge receiver 18 is used as a preliminary discharge receiver. The preliminarily ejected ink is directly stored in the corresponding sealed space 25 via the edge ejection receiver 18. In the present embodiment, as described above, both the ink discharged from the recovery unit 11 and the ink preliminarily ejected from the recording head 4 are guided into the waste ink tank 16. It is configured to be housed separately in separate locations. Further, the ink introduced from the plurality of edge discharge receptacles 18 is configured to be accommodated in independent sealed spaces 25 that individually communicate with the respective edge discharge receptacles. When the waste ink tank 16 is filled with the ink guided from the edge discharge receiver 18 or the recovery unit 11, it is replaced with a new waste ink tank.

  In the present embodiment, each edge discharge receiver 18 is formed with a suction port 22 that communicates with the fan 30. By sucking air at the inlet of the sealed space 25, the inside of each edge discharge receiver 18 is Each is an independent space that maintains negative pressure. Therefore, the ink mist ejected by the preliminary ejection is not wound up by the movement of the recording head 4. Thereby, ink stains inside the recording apparatus can be prevented. At the same time, since each edge discharge receptacle 18 is an independent space, the ink discharged there can be converted to the capacity of the ink discharged there.

  Here, the storage space is divided separately for the waste ink discharged from the edge discharge receiver 18 and the waste ink discharged from the recovery system unit 11. The waste ink discharged to each edge discharge receiver 18 is directly stored in a space provided adjacent to each of the edge discharge receivers, and is accumulated in this space and held solidified. On the other hand, the waste ink discharged from the recovery unit 11 is accommodated in the ink absorber 19 filled in the waste ink tank 16, and is absorbed and held in the ink absorber. This is because the amount of waste ink discharged from the recovery unit 11 is larger than the amount of waste ink discharged from the recording receiver 18, and it takes a longer time to evaporate and dry.

  In addition, according to such waste ink storage means, a storage capacity necessary for storing the waste ink discharged by the preliminary ejection and a storage required for storing the waste ink discharged from the recovery unit are provided. Each possible capacity can be managed independently. Therefore, the waste ink by the preliminary discharge and the waste ink by the recovery process can be efficiently stored in the waste ink tank 16, and the waste ink tank can be used efficiently. For example, the capacity for the waste ink from the edge discharge receptacle 18 can be determined based on the high ink evaporation amount, and the space for the waste ink from the recovery unit 11 is based on the low ink evaporation amount. Thus, the capacity can be determined. By independently managing the ink storage amount in this way, it is possible to design a waste ink tank without waste, and it is possible to replace it at a wasteful timing.

  In the above embodiment, the serial type ink jet recording apparatus that performs recording with the recording head mounted on the carriage that moves along the recording medium has been described as an example. The present invention can be similarly applied to a line-type ink jet recording apparatus that performs recording only by sub-scanning using a recording head for full line recording or the like, and has the same effects. In addition, the present invention can be similarly applied to any inkjet recording apparatus regardless of the number of recording heads, the number of ink types to be used, the properties, and the like, and has the same effects. . Furthermore, the present invention is not limited to a single device such as a printer, a copier, a facsimile machine, or a captured image forming apparatus. In other words, the present invention can be widely applied as a recording apparatus in a composite apparatus that combines these, or a composite apparatus such as a computer system, and has the same effects.

1 is a perspective view showing an embodiment of an ink jet recording apparatus according to the present invention. FIG. 2 is a plan view showing a preliminary discharge recovery mechanism provided on a platen of the ink jet recording apparatus of FIG. 1. FIG. 3 is a longitudinal sectional view of a preliminary discharge recovery mechanism provided in the platen of the ink jet recording apparatus according to the embodiment of the present invention as viewed from the recording medium conveyance direction. FIG. 4 is a partial cross-sectional perspective view showing a partial cross-section of the structure of the edge discharge receiver in FIG. 3. FIG. 6 is a partial plan view showing a preliminary discharge receiver and a waste ink tank of a conventional ink jet recording apparatus. FIG. 6 is a vertical cross-sectional view in a direction intersecting with a recording medium conveyance direction of a fan unit and a waste ink tank portion of a conventional inkjet recording apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Platen 4 Recording head 7 Carriage 11 Recovery unit 16 Waste ink tank 18 Edge discharge receptacle (preliminary discharge receptacle) 19 Ink absorber 22 Suction port 23 Waste ink tube 25 Space (sealed space)
26 Opening (waste ink tank)
27 Air channel 28 Suction means (suction pump)
30 Suction fan

Claims (5)

In an inkjet recording apparatus that records an image by discharging ink from a recording head to a recording medium,
An edge discharge receiver is provided at a plurality of positions corresponding to the edges on both sides of the recording medium of the platen for supporting the recording medium at a position facing the recording head,
A waste ink tank loaded with an ink absorber is disposed below the platen, and an independent space communicating with each of the edge discharge receptacles is formed inside the waste ink tank,
An ink jet recording apparatus, wherein the ink discharged from the recording head by preliminary discharge not intended for recording is received by the edge discharge receiver and the ink is accommodated in the space.   The inkjet recording apparatus according to claim 1, wherein the waste ink tank is detachable.   3. The space is communicated with the edge discharge receptacle, and the other inner surface is formed and sealed by an inner surface of the waste ink tank and a surface of the ink absorber. 2. An ink jet recording apparatus according to 1.   The inkjet recording apparatus according to claim 1, wherein the edge discharge receiver is in a negative pressure state. A capping unit for capping the recording head; and a suction pump connected to the capping unit. The ink sucked from the recording head by the suction pump is introduced into the waste ink tank and stored in the ink absorber. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus.

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