JP2007015288A - Waste ink absorption body, inkjet recording apparatus loading the waste ink absorption body, and waste ink storage container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently absorb and retain a generated waste liquid by disturbing the movement of ink into a waste ink absorption body and diffusion, when a pigment becomes suddenly unstable due to the evaporation of humidity or even when an ink liable to deteriorate in absorbing performance is used. <P>SOLUTION: The waste ink absorption body 31 has a hole part 33 containing a waste liquid introduction part 34 and a slit 32 extending from the hole part 33 formed penetrating in the width direction of the waste ink absorption body 31. The slit 32 has a width Wsl narrower than each width W1, W2 in the direction parallel with the longitudinal direction of and in the direction perpendicular to longitudinal direction of the hole part 33 and the slit 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a waste ink absorber capable of efficiently absorbing and holding waste liquid that does not contribute to recording, which occurs in an ink jet recording apparatus, and an ink jet recording apparatus equipped with the waste ink absorber.

  An ink jet recording apparatus is an apparatus that forms an image by causing ink droplets ejected from an ink jet head to fly onto plain paper or other recording media, and has achieved higher image quality, lower cost, and higher speed. It is spreading rapidly. Further, since the ink jet recording apparatus is a method of ejecting ink from the ink jet head, the ink is forcibly ejected from the ink jet head separately from recording, and a normal ejection state is maintained (head recovery process). Therefore, the ink jet recording apparatus generally includes a mechanism for forcibly discharging ink from the ink jet head for recovery processing, and a waste ink receiving tank for storing waste liquid that is ink forcibly discharged by the head recovery processing. I have. The waste ink receiving tank has a waste ink absorber, and the waste ink absorber absorbs and holds the waste liquid.

  From the background of improving the image quality of recorded images, further technological innovation has been desired for inkjet recording apparatuses, and various studies have been made on inks used, recording methods, and the like.

  For example, an ink composition using a pigment as a color material and a reaction liquid that destabilizes the color material in the ink composition are used, and the color material is agglomerated using a reaction of two liquids. Ink has been proposed that suppresses ink bleeding and color mixing (bleed) (Patent Document 1). In addition, an ink and an ink set that use a pigment as a color material and further contain a specific salt in the ink to suppress bleeding are proposed (see Patent Document 2).

  In general, as described above, as a method of obtaining high image quality by recording on plain paper, the aggregation of color materials on the paper surface is promoted as described above. Along with this, the cohesiveness of waste liquid that is not used for recording becomes high, and it is important to efficiently absorb such cohesive waste liquid in the waste ink absorber.

  As a conventional configuration for storing waste liquid, for example, a waste ink tank (see Patent Document 3) in which a recess extending to a position including a waste liquid inlet is proposed. In addition, a waste ink tank (see Patent Document 4) having a through hole into which waste ink is dropped and a notch groove radially formed from the through hole has been proposed. Further, there is proposed a waste ink absorber storage section (see Patent Document 5) in which a hole is provided in a waste ink dropping site, a protrusion is provided on the bottom, and a flow path for guiding ink is provided on the bottom. .

In addition, a waste ink absorber storage unit having a concept of suppressing waste liquid agglomeration by bringing the waste liquid discharge ports derived from pigment ink and dye ink close to each other and mixing the two inks (see Patent Document 6). Has also been proposed.
JP 2000-63719 A JP 2000-198955 A JP 2000-127439 A JP 2001-105626 A JP 2004-34412 A JP 2002-225313 A

  As a result of intensive investigations on the improvement of ink while aiming for further improvement in image performance such as image density and bleed suppression performance, the present inventors have instantaneously reduced dispersion stability and increased viscosity due to moisture evaporation and the like. It was found that the higher the ink performance, the higher the image performance. However, the absorption performance of the waste ink absorber for ink whose dispersion stability is instantaneously reduced due to such evaporation of water is lower than that of conventionally used ink, and the waste as disclosed in the related art. It has been found that there are cases where sufficient absorbability may not be obtained with an ink absorber.

  For example, in the thing of patent document 6, formation of a pigment fixed thing is suppressed by making it mix with dye ink before a pigment fixed thing is formed on a waste ink absorber, and the absorption performance of a waste ink absorber is improved. An invention to improve is disclosed. However, in the case of an ink whose dispersion stability is instantaneously reduced due to water evaporation or the like as compared with the conventional ink as examined by the present inventors, the formation of aggregates may be accelerated by mixing. It was.

  In Patent Documents 3 and 4, by forming a recess or notch groove extending from a position including the waste liquid introduction part, a phenomenon in which the waste liquid evaporates near the waste liquid introduction part and fluidity is lost is avoided. There is disclosure. However, in the case of ink whose dispersion stability is instantaneously reduced due to evaporation of water as examined by the present inventor, the ink is discarded before the drop position of the waste liquid of the ink, more specifically, the fluidity of the waste liquid is lowered. When in contact with the ink absorber, the pigment is fixed at the dropping position. As a result, the waste liquid dropped at the same position then accumulates with the fixed matter as a nucleus, and eventually may block the ink flow to the recess or notch groove. As a result, the waste liquid overflows from the vicinity of the waste liquid introduction site before the entire recess or notch groove is fully utilized, and the entire waste ink absorber cannot be effectively used after all.

  Patent Document 4 further discloses that the plurality of waste ink absorbers are stacked in the vertical direction with the notch grooves shifted from each other. As a result of the study by the present inventors, the following problems were confirmed. When the amount of the waste liquid accumulated in the notch groove of the lower layer waste ink absorber exceeds a certain amount, the waste liquid comes into contact with the upper layer waste ink absorber, and the upper layer waste ink absorber also starts to absorb the waste liquid. At that time, solid-liquid separation proceeded between the liquid component such as water and solvent in the waste liquid and the solid component such as the coloring material. That is, since the liquid component has higher permeability, it was confirmed that the waste liquid component having a relatively large amount of liquid component was absorbed by the upper layer waste ink absorber. On the contrary, the waste liquid component in which the solid component was relatively increased remained in the notch groove in the lower layer. As a result, the lower notch groove promotes the thickening of the waste liquid and the formation of aggregates, and the waste liquid is clogged near the notch groove or the waste liquid inlet, making the entire waste ink absorber effective. Could not be used.

  In Patent Document 5, a groove extending radially around the dripping portion of the waste liquid is provided on the bottom surface of the waste liquid container. However, in such a configuration, if the waste liquid is not filled until it overflows into the radially extending groove, it does not contact the waste ink absorber above the groove, so that the waste liquid is already absorbed before the waste ink absorber is absorbed. In some cases, the viscosity greatly increases or aggregates are generated due to evaporation of moisture or the like in the inside.

  As described above, it has been found that the waste liquid absorption performance of the conventional waste ink absorber is insufficient when the ink as used in the present invention is used.

  The object of the present invention is the case of using an ink whose absorption performance is likely to be lowered by abruptly destabilizing the coloring material due to evaporation of moisture, etc., and inhibiting the movement and diffusion of the ink to the waste ink absorber. However, it is to be able to efficiently absorb and retain the generated waste liquid.

In order to achieve the above object, a waste ink absorber according to the present invention is used in an ink jet recording apparatus that forms an image using ink, and a waste ink absorber that absorbs and holds waste liquid that does not contribute to the image formation.
The waste ink absorber is formed with a hole including a position where the waste liquid is introduced, and a slit extending from the hole,
The width of the connecting portion between the hole and the slit is smaller than the shortest diameter in the hole passing through the center of the position where the waste liquid is introduced. .

  According to the present invention, by forming the holes and slits having the above dimensional relationships in the waste ink absorber, the ink in which the movement and diffusion in the waste ink absorber is hindered and the absorption performance is likely to be lowered. Even if it is used, the waste liquid can be absorbed efficiently.

  The waste ink absorber of the present invention collects waste liquid generated in an ink jet recording apparatus that forms an image by discharging ink from an ink jet recording head. The ink jet recording apparatus has a recovery mechanism for maintaining discharge characteristics (head recovery processing) by forcibly discharging ink from the ink jet recording head separately from the discharge operation during recording. In addition, a waste ink absorber that absorbs and holds the waste liquid generated by the head recovery process, and an introduction unit that guides the waste liquid from the recovery mechanism to the waste ink absorber and introduces the waste liquid into the waste ink absorber.

  The waste ink absorber has a basic configuration including a hole including an introduction part that is a part into which the waste liquid guided by the introduction unit is introduced, and a slit extending from the hole. The waste ink absorber may be stored directly in the lower case of the ink jet recording apparatus, or stored in the waste ink receiving tank, but is not particularly limited.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a plan view of a waste ink absorber housed in a lower case of an ink jet recording apparatus according to a first embodiment of the present invention.

  The waste ink absorber 31 has a substantially rectangular parallelepiped shape as a whole, and has a side surface and a bottom surface that are accommodated in contact with the inner wall surface of the lower case 35 of the inkjet recording apparatus. The waste ink absorber 31 is formed with a hole 33 and a slit 32 penetrating in the thickness direction (height direction) of the waste ink absorber 31. Therefore, the bottom wall of the lower case 35 of the ink jet recording apparatus is exposed in the region where the hole 33 is formed and the region where the slit 32 is formed.

  The hole 33 is formed in the waste ink absorber 31 as a cut extending from one side surface of the waste ink absorber 31 toward the side surface facing the hole portion 33. The slit 32 extends from the middle of the hole 33 in the length direction in the direction perpendicular to the hole 33 with the width Wsl and reaches the side surface of the waste ink absorber 31. Regarding the dimension of the hole 33, when the width in the direction parallel to the longitudinal direction of the slit 32 is W1, and the width in the direction perpendicular to the longitudinal direction of the slit 32 is W2, the width Wsl of the slit 32 is the hole 33. Each width W1 and W2 is narrower than both. The width Wsl of the slit 32 refers to a dimension in a direction perpendicular to the longitudinal direction of the slit 32.

  The waste ink absorber 31 is not particularly limited as long as it is a material having a function of appropriately holding waste liquid. A porous body such as a sponge or a fibrous body made of pulp, or a polymer absorber or a member obtained by coating a polymer absorber on a paper body can be suitably used.

  The waste liquid is dripped from the waste liquid introduction part 34 located inside the hole 33. The waste liquid introduction unit 34 indicates a position where the waste liquid is introduced by an introduction unit such as a tube that guides the waste liquid generated by the recovery process to the waste ink absorber 31. Thus, since the waste liquid introduction part 34 is located inside the hole part 33, in the case of the configuration as shown in FIG. 1, the waste liquid is directly dropped onto the bottom wall surface of the lower case 35 of the ink jet recording apparatus. .

  The waste ink absorber of the present invention is characterized in that the width of the connecting portion between the hole and the slit is smaller than the shortest diameter in the hole passing through the center of the position where the waste liquid provided in the hole is introduced. This feature will be described as a specific example with reference to FIG. The slit 32 in FIG. 1 extends in the direction of the lower case of the ink jet recording apparatus while maintaining substantially the same width from the connecting portion with the slit 32. Therefore, the width of the connecting portion between the hole 33 and the slit 32 in FIG. 1 means Wsl. Moreover, the shortest diameter in the hole 33 which passes through the center of the position where the waste liquid is provided provided in the hole 33 means W1. In the present invention, the width of Wsl is smaller than the width of W1.

  In addition, the above demonstrated as an example the case where the hole 33 had a rectangular shape. However, the shape of the hole 33 is not limited to this, and may be any shape such as a circle, a polygon, or a shape shown in FIGS. In any case, the width of the connecting portion between the hole and the slit of the present invention and the shortest diameter in the hole passing through the center of the position where the waste liquid provided in the hole is introduced are the same as described above. It should reflect the way of thinking.

  Further, a part of the dropped waste liquid needs to come into contact with the waste ink absorber at least before the dispersion stability of the coloring material is impaired by moisture evaporation. Therefore, the introduction position of the waste liquid introduction part 34 and the length of W1 need to be in a form in consideration of the above contents. Part of the waste liquid dropped into the hole 33 from the waste liquid introduction part 34 is absorbed by the waste ink absorber 31, and at the same time, the remaining part moves to the slit 32 so as to be sucked into the slit 32. . The slit 32 has a dimensional relationship as described above with respect to the hole 33. When the waste ink absorber 31 is formed in such a shape, when ink that tends to deteriorate the absorption performance is obstructed by movement or diffusion of the waste liquid to the waste ink absorber 31 due to aggregation or viscosity increase due to evaporation of moisture or the like. Even so, the absorption capacity of the waste liquid is dramatically improved. Although the reason is not clear, the present inventors consider as follows.

  First, the presence of a boundary 39 between the slit 32 and the hole 33 can be mentioned. When this boundary portion 39 exists, a force of the waste liquid toward the slit 32 acts due to the capillary force of the waste ink absorber 31 itself. Therefore, an ink flow from the waste liquid introducing portion 34 toward the slit 32 occurs. The waste liquid that has moved in the direction of the slit 32 spreads while being absorbed by the waste ink absorber wall 40 that forms the slit 32.

  Secondly, the size relationship between the widths W1 and W2 of the hole 33 and the width Wsl of the slit 32 itself is configured to generate a so-called capillary phenomenon. That is, the waste liquid introduced into the hole 33 from the waste liquid introduction part 34 is subjected to a force that moves to the narrower slit 32. The introduction position of the waste liquid introduction part 34 is preferably dropped so that the waste liquid immediately after dropping is in contact with the boundary part 39.

  By these two actions, it is considered that the absorption capacity of the waste liquid is dramatically improved. Patent Documents 3 and 4 disclose forming a recess or a notch groove extending from a position including a waste liquid introducing portion as described above. However, since Patent Documents 3 and 4 do not describe the width of the waste liquid introduction portion and the width of the slit, and the drawings are drawn with the same width in the drawings, the idea of the present invention cannot be read at all. It is also difficult to easily come up with the present invention from these techniques.

  2 and 3 show examples in which one of the widths W1 and W2 of the hole 33 is the same as or narrower than the width Wsl of the slit 32 as a reference example of the present invention.

  In FIG. 2, the width Wsl of the slit 32 is equal to the width W1 of the hole 33 in the direction parallel to the slit 32. Therefore, when the waste liquid is introduced from the waste liquid introduction part 34, the capillary force of the same degree as the capillary force in the direction toward the slit 32 at the intersection of the hole 33 with the slit 32 is the open end of the hole 33. It also acts in the direction toward (downward in the figure). As a result, the flow of waste liquid in the direction toward the slit 32 is greatly hindered. This tendency becomes more prominent as the width W1 of the hole is narrower.

  FIG. 3 shows an example in which the width W1 of the hole 33 in the direction parallel to the slit 32 is wider than the width Wsl of the slit 32, but the width W2 in the vertical direction is narrower than the width Wsl of the slit 32. In this case, since the capillary force acting in the opposite direction is larger than the capillary force acting in the direction from the waste liquid introducing portion 34 toward the slit 32, the slit 32 cannot be effectively used.

  FIGS. 4 and 5 are modifications of the embodiment shown in FIG. 1, and both show an example in which two slits 32 extend from the hole 33. Of course, the width Wsl of each slit 32 is narrower than the width W1 of the hole 33. The number of slits 32 extending from the hole 33 is not particularly limited. However, if the number of the slits 32 is too large, the volume of the waste ink absorber 31 itself is reduced, and the total absorption capacity of the waste liquid is reduced. The slits 32 do not have to be parallel to each other, and may extend radially from the hole 33, for example.

  The width Wsl of the slit 32 is not particularly limited as long as the conditions defined in the present invention are satisfied. However, if the width Wsl of the slit 32 is too narrow, the slit 32 itself may be blocked by the thickened waste liquid. Conversely, if the width Wsl of the slit 32 is too thick, the total volume of the waste ink absorber 31 is reduced, and the amount of waste liquid that can be absorbed is reduced. For this reason, the width Wsl of the slit 32 is preferably 3 mm or more and 15 mm or less, and more preferably 3 mm or more and less than 5 mm. Furthermore, the width W1 of the hole 33 is preferably 6 mm or more and 30 mm or less, and more preferably twice or more the width Wsl. By making the width W1 more than twice the width Wsl, depending on the position of the waste liquid introduction part 34, the action of the capillary force, which is the technical idea of the present invention, may appear very significantly. Further, the width W2 of the hole 33 is preferably 6 mm or more and 30 mm or less, and more preferably twice or more the width Wsl. By making the width W2 more than twice the width Wsl, depending on the position of the waste liquid introduction part 34, the action of the capillary force, which is the technical idea of the present invention, may appear very significantly.

(Second Embodiment)
FIG. 6 is a plan view of the waste ink absorber housed in the lower case of the ink jet recording apparatus according to the second embodiment of the present invention.

  The shape of the waste ink absorber 31, such as the positions and dimensions of the holes 33 and the slits 32 shown in FIG. 6, is the same as that shown in FIG. 4, but the position of the waste liquid introduction part 34 is the same as that shown in FIG. Different. In other words, in the present embodiment, the waste liquid introduction part 34 is located at the intersection of the center line of the hole 33 in the width W1 direction and the center line of the slit 32 in the width Wsl direction.

  In this embodiment, since the waste liquid introduction part 34 is located at the center of the intersection of the hole 33 and the slit 32 as described above, the number of boundary portions 39 that effectively act to guide the waste liquid to the slit 32. However, it is doubled compared to the configuration shown in FIG. That is, in the embodiment shown in FIG. 4, the slit 32 extends in the middle of the flow direction of the waste liquid from the waste liquid introduction part 34 with respect to the hole 33. For this reason, the boundary portions 39 that effectively act as the source of the force for guiding the waste liquid in the direction of the slit 32 are two places on the upstream side with respect to the flow direction of the waste liquid. On the other hand, in the form shown in FIG. 6, since the distance from the position of the waste liquid introduction part 34 to all the boundary parts 39 of the hole 33 and the slit 32 is equal, the four boundary parts 39 act effectively. . As a result, the waste liquid can be guided to the slit 32 more efficiently.

(Third embodiment)
FIG. 7 is an exploded perspective view of the lower case of the ink jet recording apparatus containing the waste ink absorber and the waste ink absorber according to the third embodiment of the present invention.

  The waste ink absorber of this embodiment has a hole 33 and a slit 32, respectively, and has a configuration in which two waste ink absorbers 31 stacked on each other are accommodated in a lower case of the ink jet recording apparatus. The waste ink absorbers 31 are formed in the same shape and size as each other including the hole 33 and the slit 32, and are stacked so that the positions of the hole 33 and the slit 32 are substantially completely overlapped. Although FIG. 7 shows an example in which the hole 33 does not reach the side end surface of the waste ink absorber 31, various configurations described in the above embodiments can be applied. The slit 32 is not limited to that shown in FIG. 7, and various configurations described in the above embodiments can be applied. Further, the number of stacked waste ink absorbers 31 may be three or more.

  As shown by the white arrow, the waste liquid is dripped from above the waste ink absorber 31 and is disposed on the bottom wall surface of the lower case 35 of the inkjet recording apparatus in the region where the hole 33 is opened. 34 is introduced into the waste ink receiving tank. Although the introduction position of the waste liquid introduction unit 34 is not particularly limited, as described above, a part of the dropped waste liquid is discarded before at least the dispersion stability of the coloring material is impaired by moisture evaporation. It is necessary to contact the absorber.

  As in the present embodiment, a configuration in which a plurality of waste ink absorbers 31 are stacked on each other includes a hole 33 including a waste liquid introduction part 34 and a slit 32 that extends from the hole 33 and is narrower than the width of the hole 33. The effect of the shape of the waste ink absorber 31 having the above is exhibited most. This effect is due to an increase in the vertical height of the boundary portion 39. That is, by stacking a plurality of waste ink absorbers 31, even if a small amount of fixed matter is generated near the boundary portion 39, the waste ink absorber 31 including the boundary portion 39 exists up to a higher position. Will come to do. Therefore, a force acts constantly so that the waste liquid flows in the direction in which the slit 32 extends over the fixed matter by the capillary action that works upward and the capillary action that works in the direction in which the slit 32 extends. As a result, the waste liquid spreads firmly to the tip of the slit 32, spreads from there to the entire plane, and finally, it becomes possible to effectively absorb the waste liquid three-dimensionally from the lowest layer to every corner. .

  Although there is a conventional example in which the waste ink absorber 31 is stacked in the vertical direction, there is no conventional example that can conceive a technique like the present invention. For example, in the example disclosed in Patent Document 3, the lower layer slit is completely covered with the upper layer. In this case, the solid-liquid separation proceeds as described above. In Patent Document 4, it is disclosed that the cutout grooves are shifted and overlapped so as not to overlap each other, and it is not intended to stack the cutout grooves at the same position.

  The thickness of the waste ink absorber 31 in the height direction is preferably at least 8 mm or more in total for obtaining the effects of the present invention. Furthermore, it is more preferable that it is 10 mm or more.

  When two or more layers of the waste ink absorber 31 are stacked, it is preferable to use the waste ink absorber 31 with finer pores as the upper layer of the waste ink absorber 31. As a result, the upper layer side has a greater capillary force than the lower layer side due to the relationship between the waste ink absorbers 31 adjacent to each other vertically, so that the capillary force works upward between the adjacent layers, and the waste liquid is transferred from the lower layer to the upper layer. It becomes easier to absorb.

  The size of the pores of the waste ink absorber may be prepared by changing the compression ratio using the same material, or materials having different materials themselves may be used.

  Further, the holes 33 and the slits 32 of at least two or more layers of the waste ink absorber 31 to be stacked may be arranged so that the holes and the slits substantially overlap even if they are not completely the same. Thus, the effect of the present invention is exhibited.

(Fourth embodiment)
FIG. 8 is an exploded perspective view of the lower case of the inkjet recording apparatus that houses the waste ink absorber and the waste ink absorber according to the fourth embodiment of the present invention.

  The present embodiment has a configuration in which two waste ink absorbers 31a and 31b, each having a hole 33 and a slit 32, are stacked in a lower case 35 of the inkjet recording apparatus. The upper layer waste ink absorber 31 a has the hole 33 and the slit 32, and the lower layer waste ink absorber 31 b does not have the hole 33 and the slit 32. FIG. 8 shows an example in which the hole 33 does not reach the side end surface of the waste ink absorber 31a, but various configurations described in the above embodiments can be applied. The slit 32 is not limited to that shown in FIG. 8, and various configurations described in the above embodiments can be applied. In addition, the number of stacked waste ink absorbers 31a and 31b is further increased by stacking waste ink absorbers having holes 33 and slits 32 or waste ink absorbers having no holes 33 and slits 32. It can be more than a layer.

  As indicated by the white arrow, the waste liquid is dripped from above the upper layer waste ink absorber 31a, and from the waste liquid introduction unit 34 located in the lower layer waste ink absorber 31b in the region where the hole 33 is opened. be introduced. The introduction position of the waste liquid introduction unit 34 is not particularly limited.

  The thickness in the height direction of the waste ink absorbers 31a and 31b is preferably at least 8 mm or more in total for obtaining the effects of the present invention. Furthermore, it is more preferable that it is 10 mm or more.

  When two or more layers of waste ink absorbers are stacked, it is preferable to use a waste ink absorber with finer pores as the upper layer of waste ink absorber. As a result, the upper layer side has a greater capillary force than the lower layer side due to the waste ink absorbers adjacent to each other vertically, so that the capillary force works upward between the adjacent layers, and the waste liquid is moved from the lower layer to the upper layer. It becomes easier to absorb.

  The size of the pores of the waste ink absorber may be prepared by changing the compression ratio using the same material, or materials having different materials themselves may be used.

  Although the present invention has been described above by taking several embodiments as examples, the shape of the hole and the like applicable to each embodiment described above will be described below.

  It is necessary for the size of the hole to be wider than the width of the slit in order to exhibit the effects of the present invention. The specific size is not particularly limited, but when the waste liquid discharged by a single recovery operation is dropped onto the waste liquid introduction part, the dropped waste liquid droplet comes into contact with at least a part of the waste ink absorber. It is preferable that the size is large.

  The shape of the hole is preferably set so that the surface energy of the waste liquid is not in an equilibrium state in the region where the waste liquid contacts on the inner surface (inner cross section) of the hole.

  In addition, the area | region where the waste liquid droplets said by this invention means the point where the waste liquid 4 and the part of the air | atmosphere and the waste ink absorber 31 contact | abut, as shown to the area | regions A and B of FIG. 9, for example.

  Further, the phenomenon that “the surface energy of the waste liquid is not in an equilibrium state” means a phenomenon in which the waste liquid 4 is absorbed in a certain direction with respect to the waste ink absorber 31d as shown in FIG. In FIG. 10, reference numeral 33d indicates a hole.

  Conversely, as a specific example of the phenomenon that “the surface energy of the waste liquid is in an equilibrium state”, that is, the surface energy becomes uniform in any direction, an example as shown in FIG. In FIG. 11, a hole 2 a having a circular cross section is formed in the waste ink absorber 2. The bottom surface is raised in a dome shape in the region where the hole 2a of the waste ink absorber 2 is opened, and the top of the raised portion is the waste liquid introduction part 3. In such a configuration, the waste liquid dropped on the waste liquid introduction part 3 spreads radially by the action of gravity, and the waste liquid is in a state where the surface energy of the waste ink is uniform around the inner peripheral surface of the hole of the waste ink absorber 2. Contact with. As a result, as shown in FIG. 11A, the waste liquid is left around the center. Thereafter, the remaining waste liquid is fixed, the fixed substance becomes a nucleus, and the waste liquid can become an obstacle when absorbing and diffusing into the waste ink absorber 2. Therefore, the shape of the hole is not preferable so that the surface energy of the region in contact with the waste droplet is in an equilibrium state.

  Examples of other waste ink absorbers having holes and slits are shown in FIGS. 12 (a) to 12 (c). In the waste ink absorber 31a shown in FIG. 12A, the tip of the hole 33a has a semicircular shape. The waste ink absorber 31b shown in FIG. 12B has a shape in which two hole portions 33b formed at a distance from each other are connected to each other by a root portion and a slit. In the waste ink absorber 31c shown in FIG. 12C, the width of the hole 33c is increased toward the tip. Each of the holes 33a to 33c is not a closed hole, but a part thereof is open to the side surface of the waste ink absorbers 31a to 31c. Further, slits extend from the holes 33a to 33c.

  In addition, as another means which does not make the surface energy of the waste liquid of the area | region which the waste liquid which exists in the vicinity of a waste liquid introduction part contacts into an equilibrium state, giving at least 2 types of different surface energy to the inner surface of a hole part is mentioned. Examples of a method for imparting different surface energy include a method of subjecting a part of the inner surface of the hole to a hydrophilic treatment or a water repellent treatment. As a method of hydrophilizing or water repelling a part of the inner surface of the hole, a method of hydrophilizing or water repelling the waste ink absorber itself with a part of the inner surface of the hole, or a waste ink absorber A method of forming a part of the inner surface of the hole with another member having a different surface energy may be used. An example of the latter case is shown in FIG. The waste ink absorber 31e shown in FIG. 13 has a hole 33e with a part of the opening. And the plate 51 is attached so that the opening part of the hole 33e may be plugged up. The plate 51 is formed of a material such as a resin material, and at least a surface constituting the inner surface of the hole 33e is subjected to water repellent treatment.

  Further, in order not to bring the surface energy of the region in contact with the waste liquid into an equilibrium state, as shown in FIG. 14, the outer periphery of the introduced waste liquid 4 is not provided even when the opening is not provided in the hole. It is also possible to control the area of the hole 33f, the discharge speed of the waste liquid 4, and the like so that only a part contacts the waste ink absorber 31f.

  In the present invention, whether or not the waste ink absorber is formed so that the surface energy is not in an equilibrium state depends on whether the ink droplets formed in the holes due to the introduction of the waste liquid are not uniformly diffused in a specific direction. It is confirmed by confirming that it has diffused.

  In addition, the ink jet recording apparatus is preferably designed so that the surface energy of the region in contact with the waste liquid droplets formed by the total waste liquid discharged by one recovery operation does not reach an equilibrium state.

  If the waste droplets formed by the waste liquid discharged by one recovery operation do not come into contact with the waste ink absorber, the waste liquid will be left unabsorbed until at least the next recovery operation, and solid matter will be generated. And thickening are very likely to occur. Therefore, in order to reliably absorb the discharged waste liquid, it is important that the waste droplets formed by the total waste liquid discharged by one recovery operation come into contact with the waste ink absorber. In addition, the waste ink can be efficiently absorbed by the waste ink absorber by not bringing the surface energy of the region in contact with the waste droplets into an equilibrium state.

  The recovery operation in the present invention refers to an operation of recovering the ink discharge performance of the recording head by sucking out the fixed ink or the thickened ink inside the ink discharge port of the recording head. Usually, depending on the non-recording operation time, the amount of waste liquid discharged during one recovery operation may differ, but the one recovery operation in the present invention is the recovery operation determined by the recording device, It means the case of minimum waste liquid discharge. Therefore, when a larger amount of waste liquid is discharged, some of the waste liquid droplets formed by the discharged waste liquid come into contact with the waste ink absorber storage unit.

  In addition, it is desirable that the introduction of the waste liquid from the waste liquid introduction unit to the waste ink absorber is performed in a non-contact state with the waste ink absorber, the lower case of the inkjet recording apparatus main body, or the waste ink tank main body. The non-contact state means that the waste liquid discharged from the waste liquid introducing means is discharged without contacting the waste liquid introducing means and the waste ink absorber, the lower case, or the bottom of the tank body at the same time.

  Note that the waste ink tank main body means a tank that stores a waste ink absorber.

  In the case where the waste liquid comes into direct contact with the waste ink absorber, it is not preferable because a sticking substance is easily generated in the cross section of the hole and the waste liquid introducing means may be blocked.

  The shape of the hole is not particularly limited as long as the surface energy of the ink droplet formed by the ink discharged during one recovery operation is not in an equilibrium state, but the width is wide in both the parallel and vertical directions to the slit. Is essential.

  The shape of the slit is not particularly limited and can be used. A preferred specific embodiment is shown in FIG. 15, but is not limited thereto. FIG. 15A is a plan view of the waste ink absorber 31 housed in the lower case 35 of the ink jet recording apparatus, and is shown by a cross-sectional view taken along a line A-B in FIG. Examples of the shape of the slit are shown in FIGS.

  The slit 32 shown in FIG. 15B has a shape in which the width Wsl of the slit 32 is equal between the upper part and the lower part. The slit 32 shown in FIG. 15C has a shape in which the upper slit width is wider than the lower slit width Wsl. The slit 32 shown in FIG. 15D has a shape in which the upper slit width is narrower than the lower slit width Wsl.

  Next, examples of inks and coloring materials that can be preferably used in the present invention will be described. The present invention has a more excellent effect in an ink in which a coloring material is deposited in a waste ink absorber when an ink for the purpose of further improving the bleeding performance is generated. Can be demonstrated. When pursuing the cause or cause of such a phenomenon, the characteristics of the color material alone, the relationship between the color material and the solvent, a new phenomenon of the mixed state, and the like described below can be given. However, the present invention is not limited to the following, and it goes without saying that the present invention is effective for various ink color materials and inks that bring about the phenomenon newly found.

  The ink with improved bleed performance is, for example, a self-dispersing pigment (carbon black or the like) in which a functional group having hydrophilicity is bonded directly or through another atomic group as a coloring material, At least one kind of water-soluble organic solvent uses a water-soluble organic solvent, which is a poor solvent having a characteristic of reducing the dispersion stability of the pigment (first ink). When the ink as described above is applied to the recording medium, the ratio of the poor solvent to the pigment increases as the water evaporates, so that the pigments start to aggregate in the upper layer portion of the recording medium. As a result, there is an effect that bleed can be suppressed as a single unit or when there is other ink in the vicinity. Further, as the color material of the first ink, when a pigment having a high density with respect to the pigment surface of the hydrophilic group bonded to the pigment surface is used as the color material, the above-mentioned advantages and the color material on the waste ink absorber are used. Is fixed, and the phenomenon in which the absorption performance of the waste ink absorber is extremely lowered becomes more prominent. In this case, due to the steric hindrance due to the color material structure, the solvent in the ink is less likely to solvate with the pigment as compared with the conventional self-dispersing pigment, and the dispersion stability of the pigment tends to decrease with a slight water evaporation. . As a result, there is an effect of further reducing bleeding.

  Furthermore, an ink whose viscosity or particle size increases as the water evaporates, more specifically, an ink whose average particle size before and after evaporation changes by 25% or more when water evaporates from the liquid by 40%. Makes it possible to further reduce bleeding. The particle size can be easily confirmed by measuring the particle size without dilution, for example, with a concentrated particle size analyzer FPAR-1000 (trade name; manufactured by Otsuka Electronics Co., Ltd.).

  Further, when the viscosity is measured by mixing the first ink and the second ink, the first ink and the second ink whose viscosity is higher than any of the viscosity of the first ink and the second ink. In the case of such ink, there is an effect of further reducing bleeding.

  In the case of the ink as described above, if the ink in the ink is hard to be absorbed and the water in the ink evaporates and aggregates are formed or thickened, the recovery operation is repeated to newly evaporate the water. Even if a small amount of waste liquid is supplied, it is difficult to re-disperse or reduce the viscosity to the original level.

  The degree of evaporation from the waste liquid varies depending on, for example, the material of the waste liquid tube or the like, the inner diameter of the tube, and the amount of the waste liquid discharged in one recovery operation. However, the material of the waste liquid tube and the tube inner diameter that are generally used are limited, and the amount of waste liquid discharged in one recovery operation is generally within a predetermined range.

  There is a clear difference in the absorption performance of the waste ink absorber between the case where the waste ink absorber of the present invention is used and the case where the waste ink absorber of the present invention is not used as the waste ink absorber used in the ink jet recording apparatus on which the above ink is mounted. .

  The poor solvent in the present invention is “a pigment dispersion containing about 50% by mass of the solvent to be determined and containing the coloring material used in the ink in a dispersed state at 48 ° C. for 48 hours. The particle size in the liquid does not contain the solvent to be judged or contains a small amount, and is larger than the particle size of the pigment dispersion containing the water-insoluble colorant used in the ink in a dispersed state. It is a solvent shown. A good solvent is a solvent that exhibits properties other than a poor solvent.

  For the waste ink absorber of the present invention, the waste liquid derived from the second ink other than the ink (first ink) containing the solvent and the color material as described above and the solvent containing the poor solvent for the color material. Can be absorbed by the waste ink absorber of the present invention. The introduction position of the waste liquid derived from the second ink with respect to the waste ink absorber is not particularly limited. However, when the waste liquid derived from the first ink and the waste liquid derived from the second ink contact on or inside the waste ink absorber, the diffusion or movement of both waste liquids into the waste ink absorber is hindered. Therefore, it is necessary to consider the positions where both waste liquids are introduced into the waste ink absorber. More specifically, when each waste liquid is introduced into the waste ink absorber, the solvent contained in the first ink can diffuse or move in the waste ink absorber alone, and the moved waste liquid, It is necessary to separate the waste liquid derived from the second ink by a distance that allows contact with the waste liquid. More specifically, as shown in FIG. 16, the introduction position 12 of the waste liquid derived from the first ink and the introduction position 13 of the waste liquid derived from the second ink in the waste ink absorber. The shortest distance is 5 cm or more and 20 cm or less.

  At the bottom of the introduction positions 12 and 13 of the waste liquid derived from the first and second inks in FIG. 16, a plastic plate having no ink absorbability is provided. Each waste liquid is dropped onto the plastic plate, and then the waste liquid diffuses into the waste ink absorber.

  Further, as shown in FIG. 16, the waste liquid derived from the ink having a relatively high diffusion speed to the waste ink absorber is provided at the introduction position 12 of the waste liquid derived from the ink having a relatively low diffusion speed to the waste ink absorber. It is possible to use the waste ink absorber more efficiently by making it relatively higher than the introduction position 13.

  The diffusion rate of the waste liquid to the waste ink absorber can be compared by the following method.

  That is, the same material as the waste ink absorber used for the waste ink absorber of the ink jet recording apparatus is used, and the size is 5 mm wide × 150 mm long × 5 mm thick. Prepare 10 ml of liquid to be measured in a 50 cc beaker, and put the waste ink absorber having the above size into it. After leaving for 5 minutes, the waste ink absorber is taken out from the beaker, the distance traveled by each liquid is measured, and the diffusion rate is calculated.

  An example of the second ink that inhibits the diffusion or movement of both liquids into the waste ink absorber when the first and second inks come into contact with each other is shown. For example, when the second ink contains a solvent that is a poor solvent for the pigment contained in the first ink for the purpose of further reducing bleeding on the recording medium, and further, a coloring material Ink having at least a colorant having a structure having a benzene ring at the end (or a part having a hydrophilic part as long as the hydrophobic part is mostly present) may be used. Color materials having a structure having a benzene ring at the end generally have a property of being easily adsorbed to a pigment. Accordingly, since the dispersion stability of the pigment is inhibited, when the waste liquid derived from the first and second inks comes into contact with the waste ink absorber, a barrier that inhibits diffusion or movement into the waste ink absorber is provided. Easy to configure. Therefore, the subject in this invention generate | occur | produces notably and the effect made by solving the subject becomes remarkable.

  Furthermore, even when the first ink and the second ink have the following relationship, it is necessary to define the introduction position of the waste liquid derived from each ink as described above. Specifically, the first ink and the second ink are in a relationship in which when the viscosity is measured by mixing both inks, the viscosity becomes higher than any of the viscosity of the core ink alone.

  In the case of the ink as described above, if the ink in the ink is hard to be absorbed and the water in the ink evaporates and aggregates are formed or thickened, the recovery operation is repeated to newly evaporate the water. Even if a small amount of waste liquid is supplied, it is difficult to re-disperse or reduce the viscosity to the original level.

  Specific examples of the second color material that makes it easy to form a barrier that inhibits diffusion or movement into the waste ink absorber when the waste liquid derived from the first and second inks comes into contact with the waste ink absorber are as follows. The coloring materials represented by the structural formulas (1) and (2) are given.

(In the structural formula (1), R ₁ represents a hydrogen atom, an alkyl group, a hydroxy lower alkyl group, a cyclohexyl group, a mono- or dialkylaminoalkyl group, or a cyano lower alkyl group, and Y represents a chlorine atom, a hydroxyl group, An amino group, or a mono- or dialkylamino group (which may have a substituent selected from the group consisting of a sulfo group, a carboxyl group, and a hydroxyl group on the alkyl group), R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a carboxyl group (provided that R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are all hydrogen atoms. Except in the case of).)
Specific examples of the compound represented by the structural formula (1) include an exemplified compound having the following structure in the form of a free acid, and an exemplified compound of M7 is particularly preferably used.

(In Structural Formula (2), l = 0-2, m = 1-3, n = 1-3, where l + m + n = 3-4, and the substitution position of the substituent represents the 4 or 4 ′ position. , M represents an alkali metal or ammonium, and R ₁ and R ₂ each independently represents a hydrogen atom, a sulfo group, or a carboxyl group (provided that R ₁ and R ₂ are simultaneously hydrogen atoms). Y represents a chlorine atom, a hydroxyl group, an amino group, or a mono- or dialkylamino group.)
The coloring material represented by the structural formula (2) is a 4-sulfophthalic acid derivative or a phthalocyanine compound obtained by reacting a 4-sulfophthalic acid derivative and an (anhydrous) phthalic acid derivative in the presence of a metal compound as a raw material. After converting the group into a chlorosulfone group, a phthalocyanine compound reacted with an aminating agent in the presence of an organic amine, that is, the 4 and 4 ′ positions in the structural formula (2) (R ₂ in the structural formula (2), R ₃ , R ₆ , R ₇ , R ₁₀ , R ₁₁ , R ₁₄ , R ₁₅ ) are introduced to introduce an unsubstituted sulfamoyl group (—SO ₂ NH ₂ ) and a substituted sulfamoyl group (the following structural formula (3)) It has been found that an ink using such a compound as a coloring material has extremely excellent environmental gas resistance.

  Specific examples of the compound represented by the structural formula (3) include an exemplary compound having the following structure in the form of a free acid, and an exemplary compound of C1 is particularly preferably used.

  By using the first ink and the second ink having the above characteristics, the bleed performance can be remarkably improved as compared with the conventional ink. However, when each of the above-mentioned waste liquids is dropped on an adjacent portion of the waste ink absorber, a phenomenon that has not occurred in the past, that constitutes a barrier that inhibits diffusion or movement into the waste ink absorber. Has caused.

  In addition, there is a preferable aspect of the present invention in which the first ink is a black ink having a pigment as a color material, and the second ink is a black ink having a dye as a color material. In this case, the black ink having a preferable dye in the color material is the same as that in the case of the color ink, but the color material represented by the following structural formulas (4) and (5) is preferably used as the color material. Is mentioned.

(In Structural Formula (4), R ₁ and R ₂ represent a hydrogen atom, a hydroxyl group, an amino group, a carboxyl group, a sulfo group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. , R ₃ , and R ₄ are carbon atoms that may be substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxyl group, or an alkoxy group having 1 to 4 carbon atoms. Substituted by an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms which may be substituted with a sulfo group or a carboxyl group, or an alkyl group or an acyl group. And n is 0 or 1).

(In the structural formula (5), R ₅ , R ₆ , R ₇ and R ₈ are a hydrogen atom, a hydroxyl group, an amino group, a carboxyl group, a sulfo group, an alkyl group having 1 to 4 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. An alkoxy group, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an alkoxy group substituted with a sulfo group or a carboxyl group, an alkoxy group having 1 to 4 carbon atoms that may be further substituted with a carboxyl group or a sulfo group, An amino group substituted by a phenyl group, an alkyl group, or an acyl group, and n is 0 or 1).

  Hereinafter, exemplary compounds Bk1 to Bk3 as specific examples of the dye represented by the structural formula (4) and exemplary compounds Bk4 to Bk6 as specific examples of the dye represented by the structural formula (5) are shown in the form of free acid. The color material used in the invention is not limited to these. Further, two or more kinds of coloring materials listed below may be used at the same time, and those using the exemplified compound Bk3 and the exemplified compound Bk4 at the same time are particularly preferable.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these unless it exceeds the gist.

(Used ink)
(Preparation of pigment dispersion for black ink)
To a solution obtained by dissolving 5 g of concentrated hydrochloric acid in 5.5 g of water, 1.5 g of 4-amino-1,2-benzenedicarboxylic acid was added while being cooled to 5 ° C. Next, the container containing the solution was placed in an ice bath and the solution was stirred to keep the solution constantly at 10 ° C. or lower, and 1.8 g of sodium nitrite was dissolved in 9 g of water at 5 ° C. The solution was added. After the solution was further stirred for 15 minutes, 6 g of carbon black having a specific surface area of 220 m ² / g and a DBP oil absorption of 105 mL / 100 g was added with stirring. Thereafter, the mixture was further stirred for 15 minutes. The obtained slurry was filtered with a filter paper (trade name: Standard filter paper No. 2; manufactured by Advantech), and then the particles were sufficiently washed with water and dried in an oven at 110 ° C. to prepare self-dispersing carbon black. Further, water was added to the obtained self-dispersing carbon black and dispersed so that the pigment concentration became 10% by mass, thereby preparing a dispersion. By the above method, a pigment dispersion was obtained in a state where self-dispersing carbon black having —C ₆ H ₃ — (COONa) ₂ groups introduced on the surface of carbon black particles was dispersed in water.

(Preparation of ink)
-Preparation of black ink 1;
The above pigment dispersion (35 parts by mass), glycerin (7.0 parts by mass), diethylene glycol (6 parts by mass), diammonium phthalate (0.5 parts by mass), acetylenol E100 (manufactured by Kawaken Fine Chemical Co., Ltd., acetylene glycol) Ethylene oxide adduct) (0.2 parts by mass) and water (45.3 parts by mass) were mixed and stirred for 1 hour. Then, it pressure-filtered with the filter (Fuji Film FR20), and the black ink 1 was prepared. The viscosity of the black ink 1 at 25 ° C. was 2.3 mPa · s.

-Preparation of yellow ink 1;
C. I. Direct yellow 132 (4 parts by mass), glycerin (7 parts by mass), polyethylene glycol 600 (4 parts by mass), 2-pyrrolidone (5 parts by mass), acetylenol E100 (manufactured by Kawaken Fine Chemical Co., Ltd., ethylene oxide adduct of acetylene glycol) ) (1 part by mass) and water (79 parts by mass) were mixed and stirred for 1 hour. Thereafter, the mixture was filtered under pressure with a filter (FR20 manufactured by Fuji Film) to prepare yellow ink 1. The viscosity of Yellow Ink 1 at 25 ° C. was 2.0 mPa · s.
(Inkjet recording device)
A PIXUS550i (trade name; manufactured by Canon) is modified as an ink jet recording apparatus so that a rectangular waste ink receiving tank as shown in FIG. 17 can be accommodated, and a tube for introducing the waste liquid into the waste ink absorber accommodating portion is provided. A remodeling machine was prepared that was provided on the black ink side and the color ink side, respectively, so that the position of the waste liquid introduction part could be freely adjusted.

  The recording apparatus main body was mounted with only black ink and evaluated.

  As the waste ink absorber, a material composed of pulp fiber as a main material was processed into a shape shown in each of Examples and Comparative Examples and used.

(Viscosity of mixed ink)
The black ink 1 and the yellow ink 1 were mixed at a ratio of 1: 1 and sufficiently stirred. Then, when the viscosity of the mixed liquid at 25 ° C. was measured, it was 3.0 mPa · s, and it was found that the viscosity was increased by mixing two inks.

Example 1
As shown in FIG. 17, a waste ink absorber 31 in which a hole 33 and a slit 32 are formed is accommodated in a lower case 35 of an ink jet recording apparatus. The thickness of the waste ink absorber 31 was 8 mm. The waste liquid introduction part 34 is located on the center line CL1 of the hole 33, but is away from the center line CL2 of the slit 32. Printing was performed using the black ink 1, and the waste liquid was dropped from the waste liquid introduction unit 34.

  When the inner surface of the hole 33 of the waste ink absorber 31 was observed after one recovery operation, a part of the waste liquid was in contact with the waste ink absorber 31.

(Example 2)
A waste ink absorber having the structure shown in FIG. 18 was used. This is different from the first embodiment in the position of the waste liquid introduction part 34. In this example, the waste liquid introduction part 34 is located at the intersection of the center line CL1 of the hole 33 and the center line CL2 of the slit 32. . The thickness of the waste ink absorber 31 was 8 mm. Printing was performed using the black ink 1, and the waste liquid was dropped from the waste liquid introduction unit 34.

  When the inner surface of the hole 33 of the waste ink absorber 31 was observed after one recovery operation, a part of the waste liquid was in contact with the waste ink absorber 31.

(Example 3)
A waste ink absorber having the structure shown in FIG. 7 was used. The total thickness of the waste ink absorber 31 was 14 mm. Printing was performed using the black ink 1, and the waste liquid was dropped from the waste liquid introduction unit 34.

  When the inner surface of the hole 33 of the waste ink absorber 31 was observed after one recovery operation, a part of the waste liquid was in contact with the waste ink absorber 31.

(Comparative Example 1)
A waste ink absorber having the structure shown in FIG. 19 was used. That is, the waste ink absorber 31 has only the slit 32, and the waste liquid introduction part 34 is located in the slit 32. The thickness of the waste ink absorber 31 was 8 mm. Printing was performed using the black ink 1, and the waste liquid was dropped from the waste liquid introduction unit 34.

  When the inner surface of the slit 32 of the waste ink absorber 31 was observed after one recovery operation, a part of the waste liquid was in contact with the waste ink absorber 31.

(Comparative Example 2)
A waste ink absorber having the structure shown in FIG. 20 was used. That is, the waste ink absorber 31 has only the hole 33. The hole 33 does not have an open part. The thickness of the waste ink absorber 31 was 8 mm. Printing was performed using the black ink 1, and the waste liquid was dropped from the waste liquid introduction unit 34.

  When the inner surface of the hole 33 of the waste ink absorber 31 was observed after one recovery operation, the waste liquid was uniformly in contact with the waste ink absorber 31 over the entire circumference.

(Comparative Example 3)
A waste ink absorber having the structure shown in FIG. 2 was used. The thickness of the waste ink absorber 31 was 8 mm. Printing was performed using the black ink 1, and the waste liquid was dropped from the waste liquid introduction unit 34.

  When the inner surface of the hole 33 of the waste ink absorber 31 was observed after one recovery operation, a part of the waste liquid was in contact with the waste ink absorber 31.

(Comparative Example 4)
A waste ink absorber having the structure shown in FIG. 3 was used. The thickness of the waste ink absorber 31 was 8 mm. Printing was performed using the black ink 1, and the waste liquid was dropped from the waste liquid introduction unit 34.

  When the inner surface of the hole 33 of the waste ink absorber 31 was observed after one recovery operation, a part of the waste liquid was in contact with the waste ink absorber 31.

(Comparative Example 5)
A waste ink absorber having a structure having a waste ink absorber 31 laminated in two layers as shown in FIG. 21 was used. Each waste ink absorber 31 has only a hole 33, and the hole 33 does not have an opening. The total thickness of the waste ink absorber 31 was 14 mm. Printing was performed using the black ink 1, and the waste liquid was dropped from the waste liquid introduction unit 34.

  When the inner surface of the hole 33 of the waste ink absorber 31 was observed after one recovery operation, the waste liquid was in uniform contact over the entire circumference.

(Comparative Example 6)
A waste ink absorber having the structure shown in FIG. 22 was used. The thickness of the waste ink absorber 2 was 8 mm. Printing was performed using the black ink 1, and as shown in FIGS. 22 and 23A, the waste liquid 4 was dropped so that the waste liquid 4 was in contact with the entire surface of the hole 2a.

  When the inner surface of the hole 2a of the waste ink absorber 2 was observed after one recovery operation, the waste liquid was in uniform contact over the entire circumference. Further, as the waste liquid 4 was absorbed by the waste ink absorber 2, the waste liquid 4 was left in the vicinity of the center of the hole 2a as shown in FIG.

(Evaluation of waste liquid absorption performance 1)
In the ink jet recording apparatus equipped with the waste ink absorber shown in Examples 1 to 3 and Comparative Examples 1 to 6, a print pattern in which alphabets A to Z are written in black ink over several lines is printed on PPC paper ( 5 sheets were printed on Canon), after which a recovery operation was performed, and a predetermined amount of black ink 1 was introduced into the waste ink absorber. Further, every 100 sheets were left in an environment of a temperature of 30 ° C. and a humidity of 10% for 2 hours. Finally, 4000 sheets were intermittently printed while changing the ink tank as needed. The state of the waste ink absorber at that time was evaluated. The evaluation criteria were as follows.

(Evaluation criteria)
(Double-circle): Waste liquid has spread over the whole waste ink absorber. There are no or almost no aggregates in the holes and slits.
○: There is a small amount of agglomerates in the hole or slit, but the waste liquid spreads over the entire waste ink absorber, and there is no overflow of ink.
Δ: Absorbency is good up to about 3000 printed sheets. Eventually ink overflow occurs. There are many aggregates in the hole or slit.
X: Absorbability has already been reduced at about 500 printed sheets. Eventually ink overflow occurs. There are many aggregates in the hole or slit.

  The evaluation results are shown in Table 1.

(Evaluation of waste liquid absorption performance 2)
In the ink jet recording apparatus equipped with the waste ink absorber shown in Example 3 and Comparative Example 5, a print pattern in which alphabets are written from A to Z with black ink on several lines is printed on PPC paper (manufactured by Canon). Five sheets were printed, and then a recovery operation was performed, and a predetermined amount of black ink 1 was introduced into the waste ink absorber. Further, every 100 sheets were left in an environment of a temperature of 30 ° C. and a humidity of 10% for 2 hours. Finally, 5000 sheets were intermittently printed while changing the ink tank as needed. The state of the waste ink absorber at that time was evaluated. The evaluation criteria were as follows.

(Evaluation criteria)
(Double-circle): Waste liquid has spread over the whole waste ink absorber. There are no or almost no aggregates in the holes and slits.
○: There is a small amount of agglomerates in the hole or slit, but the waste liquid spreads over the entire waste ink absorber, and there is no overflow of ink.
Δ: Absorbency is good up to about 3000 printed sheets. Eventually ink overflow occurs. There are many aggregates in the hole or slit.
X: Absorbability has already been reduced at about 500 printed sheets. Eventually ink overflow occurs. There are many aggregates in the hole or slit.

  The evaluation results are shown in Table 2.

(Bleed performance evaluation)
The black ink 1 and the yellow ink 1 were used to print a black line against the background of yellow solid printing, and the bleeding suppression performance was evaluated.

It is a top view of the waste ink absorber by the 1st Embodiment of this invention. It is a top view of an example of the waste ink absorber which is a reference example of the present invention. It is a top view of the other example of the waste ink absorber which is a reference example of this invention. It is a top view which shows the modification of the waste ink absorber by the 1st Embodiment of this invention. It is a top view which shows the other modification of the waste ink absorber by the 1st Embodiment of this invention. It is a top view of the waste ink absorber by the 2nd Embodiment of this invention. It is a disassembled perspective view of the waste ink absorber by the 3rd Embodiment of this invention. It is a disassembled perspective view of the waste ink absorber by the 4th Embodiment of this invention. It is the top view and sectional drawing of a waste ink absorber explaining the area | region where waste liquid contacts. It is a top view of a waste ink absorber explaining the phenomenon which does not make the surface energy of a waste liquid into an equilibrium state. It is the top view and sectional drawing of a waste ink absorber explaining the phenomenon in which the surface energy of waste liquid becomes an equilibrium state. It is a top view of the waste ink absorber which shows the various examples of the hole which has an open part. It is a top view of an example of the waste ink absorber comprised so that at least 2 or more types of different surface energy might be provided to the inner surface of a hole. It is a top view of the waste ink absorber which shows the example which made the surface energy of the area | region which a waste droplet contacts in the hole which does not have an open part nonuniform. It is a figure which shows the various cross-sectional shapes of the slit applied to this invention. It is a perspective view which shows an example of the waste ink absorber in which multiple types of waste liquid is introduce | transduced. It is a top view of the waste ink absorber used in Example 1 of the present invention. It is a top view of the waste ink absorber used in Example 2 of the present invention. 6 is a plan view of a waste ink absorber used in Comparative Example 1. FIG. 6 is a plan view of a waste ink absorber used in Comparative Example 2. FIG. 10 is an exploded perspective view of a waste ink absorber used in Comparative Example 5. FIG. 10 is a plan view of a waste ink absorber used in Comparative Example 6. FIG. It is sectional drawing explaining absorption of the waste liquid of the waste ink absorber shown in FIG.

Explanation of symbols

31 Waste ink absorber 32 Slit 33 Hole 34 Waste liquid introduction part 35 Lower case 39 Boundary part 40 Waste ink absorber wall

Claims (13)

A waste ink absorber that is used in an ink jet recording apparatus that forms an image using ink and absorbs and holds waste liquid that does not contribute to the image formation,
A hole that opens the position where the waste liquid is introduced, and a slit that extends from the hole are formed,
A waste ink absorber, wherein a width of a connecting portion between the hole and the slit is smaller than a shortest diameter in the hole passing through a center of a position where the waste liquid is introduced.   The slit is formed in a direction perpendicular to the hole, and the width of the connecting portion between the hole and the slit is narrower than the width in the direction parallel to the longitudinal direction of the slit and the direction perpendicular thereto. The waste ink absorber according to claim 1.   The waste according to claim 1 or 2, wherein the waste liquid is introduced from an intersection of a center line in the width direction of the slit and a center line of the hole in a direction perpendicular to the width direction of the slit. Ink absorber.   The plurality of waste ink absorbers having the same dimension and the hole and slit formed therein, wherein the plurality of waste ink absorbers are stacked on each other so that the hole and slit overlap. The waste ink absorber according to 1 or 3.   The waste ink absorber according to any one of claims 1 to 4, wherein the hole has a size such that the introduced waste liquid contacts at least a part of the waste ink absorber.   6. The waste according to claim 5, wherein the hole is formed corresponding to a position where the waste liquid is introduced, and a region where the waste liquid contacts the inner surface of the hole does not bring the surface energy of the waste liquid into an equilibrium state. Ink absorber.   The waste ink absorber according to claim 6, wherein the hole portion has an open portion opened on a side surface of the waste ink absorber.   The waste ink absorber according to claim 6, wherein the inner surface of the hole is treated so that the waste liquid has at least two different surface energies.   The waste ink absorber according to claim 8, wherein a part of the inner surface of the hole is subjected to a hydrophilic treatment or a water repellent treatment.   The waste ink absorber according to claim 8, wherein a part of the inner surface of the hole portion is formed of another member that makes the surface energy of the waste liquid different from the waste ink absorber. In an inkjet recording apparatus that forms an image using ink,
A waste ink absorber according to any one of claims 1 to 10,
Waste liquid introduction means for introducing waste liquid that does not contribute to the image formation into the waste ink absorber;
An ink jet recording apparatus. A waste liquid derived from the first ink having a relatively low diffusion rate to the waste ink absorber, and a diffusion with respect to a region in which the waste ink absorber according to any one of claims 1 to 10 is stored The waste liquid derived from the second ink having a relatively high speed is an ink jet recording apparatus that is introduced from a different location of the waste ink absorber,
An ink jet recording apparatus, wherein an introduction position of the waste liquid derived from the first ink is relatively higher than an introduction position of the waste liquid derived from the second ink. In a waste ink receiving tank that is used in an ink jet recording apparatus that forms an image using ink and receives waste liquid that does not contribute to the image formation,
At least one waste ink absorber for absorbing and holding the waste liquid;
A tank body for storing the waste ink absorber,
The waste ink absorber is formed with a hole including a position where the waste liquid is introduced, and a slit extending from the hole,
A waste ink storage container, wherein a width of a connecting portion between the hole and the slit is smaller than a shortest diameter in the hole passing through a center of a position where the waste liquid is introduced.

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