Ink container cartridge

Abstract: An ink container cartridge detachably mountable to an ink jet recording head, includes a main body of ink container cartridge; an ink retaining member, in the main body, for retaining the ink; wherein the ink retaining member is contained in the ink container cartridge so that a compression ratio A of the ink retaining member by a side having an ink supply opening of the ink container cartridge and a side apposite therefrom, and a compression ratio B by other two opposite sides thereof, satisfy A > B, and 1.1 ≦ A ≦ 1.6.

Description: FIELD OF THE INVENTION AND RELATED ART The present invention relates to an ink container cartridge which is detachably mountable relative to an ink jet recording head and which contains ink to be supplied to the ink jet recording head for effecting recording by ejecting the ink onto a recording material, and more particularly to an ink container having therein an ink absorbing material. Recently, note type or lap-top type personal computer or word processor which are small in size and light in weight and therefore which are excellent in portability, have become widely used. Correspondingly, a small printer is demanded. For such a small printer, a proposal has been made, wherein an ink container is integral with a recording head, and when the ink is used up, the ink container and the recording head are all integrally replaced, and therefore, the cost-performance is not good. In view of this, a head cartridge and an ink container cartridge, have been proposed in which the ink container cartridge and the recording head are separable. Typical examples will be described. A first example is disclosed in JP-A-63 3959, wherein the ink is contained in an ink container bladder in the ink container cartridge. For the purpose of prevention of ink leakage, the ink container opening portion, namely the ink supply opening, is sealed by a sealing film member which is pierced by an ink supply tube upon the start of use. In a second example, disclosed in JP-A-5-345 420 an ink container cartridge separate from an ink jet head has a sponge for retaining the ink. When the ink jet head and the ink container cartridge are connected with each other, the supply tube presses the sponge to increase the capillary force of the sponge adjacent the ink supply tube, thus concentrating the ink to the neighborhood of the supply tube, by which the stable ink supply to the ink jet head can be accomplished. In this separable-exchangeable type ink container cartridge, only the ink container cartridge can be replaced when the ink is used up, and therefore, the cost performance has been drastically improved. However, the separable type gives rise to a problem. For example, in the case of JP-A-63-3959, the ink container bladder is used to contain the ink. If the user removes the ink container cartridge before using up the ink in the ink container cartridge, the ink in the ink container bladder is opened to the ambience since the sealing film member has been opened. If this is done, the ink leakage may occur through the ink supply opening when the ink container cartridge is removed. In order to avoid the problem, it would be considered to provide a valve at the opening portion. However, this results in cost increase, and the advantage of separable type is not available. In the case of JP-A-5-345420, the accommodation of the ink is achieved by the sponge in the ink container cartridge, and therefore, even if the ink container cartridge is removed before the ink is used up, the ink does not leak out because the capillary force of the sponge retains the ink therein. However, the sponge exists substantially uniformly in the ink container cartridge. The ink supply is stabilized by increasing the capillary force by the ink supply tube of the ink jet head pressing the sponge, thus concentrating the ink to the neighborhood of the supply tube. Therefore, when the ink container cartridge is removed in the middle of use, the sponge restores to the initial state with the result that the capillary force becomes uniform, and therefore, the ink no longer concentrates adjacent the supply opening. If the ink in the neighborhood of the opening portion is evaporated, the ink is concentrated to the central portion of the sponge. If this occurs, the ink will not become concentrated to the neighborhood of the supply tube even if the capillary force there is increased by pressing it to the sponge. Then, the remaining ink is not usable, with the result of increase of running cost. For the purpose of prevention of this problem, JP-A-5-104375 has proposed that the ink container cartridge is constituted by an ink retaining member such as sponge, and a connection member for stable supply of the ink from the ink retaining member to the ink supply tube. With this structure, the ink cutting due to the remounting of the ink container cartridge, and the cost increase of the ink container cartridge alone can be minimized. However, with this type, it is required that the ink retaining member and the connection member are contacted with each other. In the case of the ink container cartridge using the sponge, for example, the sponge deforms by the creep deformation depending on the condition of the keeping if it is kept out of use. If such an ink container cartridge receives external shock, the sponge yields in the direction of the shock. Even if the elasticity of the sponge remains, the sponge does not restore from the position to which it is moved by the yielding, unless the restoring force exceeds the friction resistance force between the absorbing material and the internal wall surfaces of the main body of the ink container cartridge. In the worst case, the contact state between connection member and ink retaining member is not kept with the result of separation therebetween. If the filling amount of ink is increased in an attempt to decrease the running cost of the ink container cartridge, the shock force and the degree of yielding is likely to increase to promote the separation between the connection member and the ink maintaining member. If the separation occurs, the ink communication therebetween is cut with the result of incapability of recording operation. An ink container cartridge comprising the features according to the pre-characterizing clause of claim 1 is known from document EP-A-0419192. This known ink container cartridge suffers from the same deficiencies as explained with regard to JP-A-5-104375. SUMMARY OF THE INVENTION Accordingly, it is a principal object of the present invention to provide an ink container cartridge capable of stably supplying the ink to a recording head despite ambience change and keeping condition. It is another object of the present invention to provide a separable type ink container cartridge wherein the ink can be stably supplied even if the ink container cartridge is demounted from a recording head during use thereof and then it is remounted. These objects are achieved by the ink container cartridge according to claim 1. Further developments of the invention are defined in the subclaims. The features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a sectional view of an ink container cartridge according to a first embodiment of the present invention. Figure 2 shows an ink retaining member according to the first embodiment before accommodation. Figure 3 is a sectional view of an ink container cartridge according to a second embodiment of the present invention. Figure 4 shows an ink retaining member according to a second embodiment before accommodation. Figure 5 is a sectional view of an ink container cartridge according to a third embodiment of the present invention. Figure 6 shows an ink retaining member according to the third embodiment of the present invention before accomodation. Figure 7 is a sectional view taken along a line QQ of Figure 5. Figure 8, (A) is a sectional view of an ink container cartridge according to a fourth embodiment of the present invention. Figure 8, (B) shows an ink retaining member according to the fourth embodiment of the present invention before accomodation. Figure 9, (A) is a sectional view of an ink container cartridge according to a fifth embodiment of the present invention. Figure 9 (B) shows an ink retaining member according to the fifth embodiment of the present invention, after it is taken out of the main body of the ink container cartridge. DESCRIPTION OF THE PREFERRED EMBODIMENT [Embodiment 1] Figure 1 is a sectional view of an ink container cartridge to which the present invention is applicable. As shown in Figure 1, a generally hexahedron main body 1 of the ink container cartridge contains therein a compressed ink retaining member 2. The ink retaining member 2 is compressed to a length L 1 by an end surface of a rib O at a side having a supply opening 4 for insertion of ink jet head supply tube and an end surface of a cap rib P disposed around an air vent 3. When inserted into the main body of the ink container cartridge 1, the ink retaining member has a width H 1 . Without any external force, the ink retaining member 2 has a rectangular parallelepiped shape having a length L 0 and a width H 0 , as shown in Figure 2. The ink retaining member 2 is compressed between the side having the ink supply opening 4 and the side faced thereto at a compression ratio L 0 /L 1 = A , and it is compressed between the other two opposite sides of the main body at compression ratio H 0 /H 1 =B . When the dimensions are as they are shown in Figures 1 and 2, they satisfy L 0 >L 1 , and D 1 >H 1 >H 0 . The ink retaining member 2 used in this first embodiment is of foamed plyurethane resin material, and the above compression ratios A are determined so as to provide proper sizes of cells for the desired negative pressure, and varies depending on the number of cells per unit length and the length L 0 before the compression. Various samples of the ink container cartridges were produced with different combinations of compression ratios A and compression ratios B. The ink was filled into the samples, and they were kept under 60 °C for one month. Then, they were dropped from a height of 90 cm on lauan material with the side opposite from the one having the ink supply opening downward. The positional deviations of the inside ink retaining member occurred were given on the table. In the Table, "A" is the compression ratio of the ink retaining member between the side having the ink supply opening and the side opposite thereto of the main body. "B" is the compression ratio of the ink retaining member between the two other opposite sides of the main body. "E = Excellent" means that no deviation of the inside ink retaining member is observed for all of 5 samples. "G = Good" means that although the deviation is observed in 1 - 2 samples out of 5 samples, the ink supply performance is not practically influenced. "F = Fair" means that although the deviation is observed in 2 - 3 samples out of 5 samples, but the ink supply performance is not practically influenced. "NG = No Good" means that the deviation is observed in 3 - 5 samples out of 5 samples, and the ink supply performance is deteriorated. As will be understood from Table 1, the satisfactory properties are provided when the compression ratio A and compression ratio B satisfy A > B, and compression ratio A is in the range of 1.1 - 1.6, and compression ratio B is in the range of 1.0 - 1.4. Further preferably, compression ratio A = 1.1 - 1.4 and compression ratio B = 1.0 - 1.2. If the compression ratio of the ink retaining member is too large, it is creased when it is inserted into the main body, with the result that it is not uniformly packed therein. If the compression ratio is too small, it may be easily moved by shock, or it may be easily yielded. Particularly, if the compression ratio B is smaller than 1.0, a gap is formed between the main body and the ink retaining member, and it may be oblique upon high compression filling of the ink retaining member Five samples were produced with the combinations of compression ratio A = 1.1, 1.2, 1.4, 1.6, and compression ratio B = 1.0, 1.1, 1.2, 1.3, 1.4. They were mounted and demounted repeatedly 10 times, and thereafter, the state of the ink retaining member at the ink supply opening side was observed. Then, the ink container cartridge is mounted to the apparatus, and the printing operation was carried out. The results are shown in Table 2. "E = Excellent" means that the ink retaining member was restored to the ink supply opening side after the ten times mounting and demounting operations. "G = Good" means that the ink retaining member was not sufficiently restored to the ink supply opening side in only 1 - 2 samples, but the printing operation was not influenced. "F = Fair" means that the ink retaining member was not restored to the ink supply opening side after the 10 times mounting and demounting, and the printing operations were not satisfactory. From overall evaluations, it is desirable in the usual conditions that the compression ratios A and B satisfy A > B. And in addition the compression ratios satisfy A = 1.1 - 1.6, B = 1.0 - 1.4, further preferably, A = 1.1 - 1.4, B = 1.0 - 1.2. With these conditions, the ink container cartridge is sufficiently practically usable even after several mounting-and-demounting operations are repeated. [Embodiment 2] Figure 3 shows a second embodiment, wherein the ink retaining member 5 to be inserted into the main body 1 of the ink container cartridge is shaped by heat-pressing quite into conformity with the shape after being inserted into the main body of the ink container cartridge (compressed absorbing material). It has been confirmed that the heat compression member of this embodiment is satisfactory without yielding in the impact test, and the satisfactory ink supply performance can be assured, as long as the above-described conditions are satisfied. In this embodiment, use is made of the ink retaining member which is heat-pressed at four of its sides except for the two sides disposed at the supply opening 4 and at the air vent 3. However, the pressing may be imparted to any side as long as the cell size after the compression is proper to provide the desired negative pressure, and the configuration does not restore to that before the heat-pressing. Since, however, the portion of the ink retaining member directly pressed is heat-cured, heat-pressing on the sides not faced to the ink supply opening is preferable. With this embodiment, the difficulty in the packing of the ink retaining member during the manufacturing of the ink container can be eased, so that the stable manufacturing is accomplished. [Embodiment 3] Figure 5 is a sectional view of an ink container cartridge according to a third embodiment, wherein reference numeral 11 designates a main body into which an ink retaining member 12 is packed with compression. A container cap 13 is bonded by ultrasonic fusing thereafter. Designated by 14 is an ink supply opening for supplying the ink to the recording head. Figure 6 shows dimensions before the compression insertion of the ink retaining member 12 into the ink container 11. In this embodiment, dimension H 0 = 25 mm between surfaces c - d, and dimension H 2 = 25 mm between surfaces e - f, and dimension L 0 = 85 mm between surfaces a - b. Figure 7 is a sectional view taken along QQ in Figure 5. Designated by 15 is a rib provided on the main body 11. On this sectional view, only the surfaces of ribs 15 are contacted to the ink retaining member 12. The main body 11 is of modified PPO, and the ink retaining member 12 is of foamed urethane resin material. Each rib 15 has a width 55 of approx. 1.5 mm, and the section of the ink retaining member 12 after the insertion has the dimensions of H 1 = 22 mm and H 3 = 22 mm. The ink retaining member 12 is compressed and inserted into the main body 11, so that it is compressed at the ratio A of 1.4 (85mm/61mm) in the ink supply direction, and is compressed at a ratio B of 1.1 (25mm/22mm) in the direction orthogonal thereto. As described with regard to the first embodiment, the compression ratio of the ink retaining member 12 in the ink supply direction is larger than that in the other directions, and therefore, the ink retaining member 12 does not separate from the ink supply opening 14 even upon impact thereto. The object of the present invention is further assured by the above-described structure. The provision of the ribs 15 on the main body 11 is effective to decrease the area in which the ink retaining member 12 is contacted to the internal surfaces of the main body 11. Therefore, the friction resistance at the side surfaces of the ink retaining member 12 except the side surface facing the supply opening 4 and the side surface opposite thereto is decreased. The frictional force upon the falling impact in the direction perpendicular to the side having the ink supply opening is reduced, so that the repelling force of the ink retaining member in the direction of the impact hardly reduces. Therefore, even upon the external shock, the ink retaining member assuredly restores its original state, thus further assuring the ink supply performance of the ink container cartridge. The inventors have found that if the contact area ratio between the internal surfaces of the main body and the side surfaces of the ink retaining member 12 (the surfaces perpendicular to the ink supply direction), is not more than 15 %, the ink supply performance of the ink container cartridge can be assured even if the it is subjected to the falling impact, or it is kept out of use for a long term. [Embodiment 4] Figure 8(A) is a sectional view of an ink cartridge according to a fourth embodiment. In Figure 8(A), an ink retaining member 22 is compressed and inserted into a main body 21. Designated by 24 is an ink supply opening for supplying the ink to the head. The ink retaining member 22 is compressed by an ink container cap 23 and a connection member 25 comprising a material having a high ink retaining property, and are balanced by a force T2. In the direction perpendicular to the direction of the force T2, the ink retaining member 22 is compressed by the internal surfaces of the main body 21, and the balance is provided by the force T1. The main body 21 is of modified PPO, and the ink retaining member 22 is of foamed urethane resin material. The space defined by the internal surfaces of the main body has the dimensions of L 1 = 65 mm and H 1 = 20 mm. Figure 8(B) shows the state of said ink retaining member 22 before insertion into the main body 21. A dimension L 0 before insertion, corresponding to L 1 is 85 mm, and the dimension H 0 before the insertion is 22 mm. Therefore, the compression ratios A and B are 1.3 and 1.1, respectively. If the foamed urethane resin material of the ink retaining member does not exhibit anisotropy relative to the compression stress, the repelling forces T1 and T2 (see Figure 8(A)) are proportional to the compression ratios. Therefore, even if the ink retaining member 22 is instantaneously separated from the connection member 25 due to an impact caused by vertically falling in the direction perpendicular to the side having the ink supply opening, the repelling force T2 of the ink retaining member in the vertical direction exceeds the opposing frictional force at the longer side surfaces of the main body, because the force T1 directed perpendicular to the longer side surfaces is smaller than the force T2. Therefore, the ink retaining member 22 is recontacted to the connection member 25. Therefore, the ink supply performance of the ink cartridge is not deteriorated. [Embodiment 5] Figure 9(A) is a sectional view of an ink container cartridge according to a further embodiment. In Figure 9(A), the ink retaining member 42 is compressed and inserted into the main body 41. The ink retaining member 42 is compressed by the ink container cap 43 and a connection member 45 inserted into the supply opening 44 for supplying the ink. The dimensions of main body 41 are L 1 = 55 mm and H 1 = 21 mm. Figure 9(B) shows a state wherein the ink retaining member 42 is taken out of the main body 41, and it is cleaned to remove the ink, and then it is dried. The dimension U6 after it is taken out (corresponding to L 1 ) is 70 mm, and the dimension W6 after it is taken out (corresponding to H 1 ) is 28 mm. By taking the ink supply member 42 out of the main body 41, it expands by 15 mm in the direction towards the supply opening, and 7 mm in the direction perpendicular thereto. The deformation amount M (= 15 mm) of the ink retaining member 42 in the supply opening direction and the deformation amount N (= 7 mm) in the direction perpendicular thereto satisfy: M > N Therefore, the repelling force of the ink retaining member in the supply opening direction exceeds the frictional force in the same direction. Therefore, even if the ink retaining member 42 is instantaneously separated from the connection member 45, the ink retaining member 42 is recontacted to the connection member 45. Accordingly, the supply performance for the ink is not deteriorated. Generally, foamed urethane resin material or the like creeps only at the position where it is to be connected with the ink supply opening, and therefore, it is not completely restored even if it is taken out of the main body, in some cases. Even in such a case, the supply performance is sufficiently assured, if the value range of the first embodiment is satisfied, since then the marginal portions have sufficient restoration power. While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth and the claims are intended to cover such modifications or changes as may come within the purpose of the improvements or the scope of the following claims.

Claims: An ink container cartridge detachably mountable to an ink jet recording head, comprising a hexahedron main body (1, 11, 21, 41) and an ink retaining member (2, 5, 12, 22, 42) contained in the main body, wherein said main body (1, 11, 21, 41) has a side provided with an ink supply opening (4, 14, 24, 44) and a side opposite thereto, wherein said ink retaining member (2, 5, 12, 22, 42) has a rectangular parallelepiped shape, wherein said ink retaining member (2, 5, 12, 22, 42) has a cellular structure and is capable of absorbing ink, wherein said ink retaining member (2, 5, 12, 22, 42) is compressed between the side having the ink supply opening (4, 14, 24, 44) and the side opposite thereto, and wherein said ink retaining member (2, 5, 12, 22, 42) is compressed between two other opposite sides of the main body, characterized in that a compression ratio A, which is defined as A = L 0 /L 1 , and a compression ratio B, which is defined as B = H 0 /H 1 , satisfy A > B and 1.1 ≤ A ≤ 1.6, wherein L 1 = length of the compressed ink retaining member (2, 5, 12, 22, 42) between the side having the ink supply opening (4, 14, 24, 44) and the side opposite thereto, L 0 = length of the ink retaining member (2, 5, 12, 22, 42) between the side having the ink supply opening (4, 14, 24, 44) and the side opposite thereto before compression, H 1 = width of the compressed ink retaining member (2, 5, 12, 22, 42) between said two other opposite sides, and H 0 = width of the ink retaining member (2, 5, 12, 22, 42) between said two other opposite sides before compression. A container according to Claim 1, wherein the compression ration B satisfies 1.0 ≤ B ≤ 1.4. A container according to Claim 1, wherein the compression ratio A satisfies 1.1 ≤ A ≤ 1.4, and the compression ratio B satisfies 1.0 ≤ B ≤ 1.2. A container according to Claim 1, wherein a contact area ratio of the side surfaces of said ink retaining member (12), except the side surface at the ink supply opening (14) and the side surface opposite thereto, relative to the internal surfaces of said main body (11), except the internal surface of the side having the supply opening (14) and the internal surface opposite thereto, is not more than 15%. A container according to Claim 1, wherein said ink retaining member (5) is heat-compressed at two of its six sides. A container according to one of Claims 1 to 5, wherein said ink retaining member (2, 5, 12, 22, 42) is of foamed polyurethane resin material.

Inventors: HAMASAKI YUJI, KOTAKI YASUO, SAIKAWA HIDEO, TAKENOUCHI MASANORI, YAMAMOTO HISASHI, HAMASAKI, YUJI, KOTAKI, YASUO, SAIKAWA, HIDEO, TAKENOUCHI, MASANORI, YAMAMOTO, HISASHI
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1995
Main classification: B41J2
IPC codes: B41J2