Refillable liquid storage tank, image forming apparatus

Abstract

To provide a supply type liquid storage tank which can apply the sufficient back pressure to the liquid while avoiding the increase in the size of a liquid supply system, and an image formation apparatus having the supply type liquid storage tank.SOLUTION: A supply type liquid storage tank to which the liquid can be supplied comprises: a tank body part to which the liquid is supplied; and a back pressure application member which is formed of an absorber absorbing the liquid and applies the back pressure to the liquid in the tank body part. An upper limit instruction part which indicates the liquid level height of the maximum amount of the liquid that can be stored in the tank body part is set in the tank body part. At least a portion of the back pressure application member is located on the upper side with respect to the upper limit instruction part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a replenishment type liquid storage tank capable of replenishing liquid, and an image forming apparatus including the replenishment type liquid storage tank. [Background technology]

[0002] Conventionally, there is known an inkjet printer that includes a liquid storage tank for storing a liquid such as ink, and consumes the liquid stored in the liquid storage tank. As the liquid storage tank, a refill type liquid storage tank that can be appropriately replenished with liquid is known (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-161851 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an inkjet printer, it is necessary to apply back pressure, i.e., negative pressure, to the ink in the liquid storage tank to form a meniscus in the ink at the tip of the nozzle so that ink does not leak from the nozzle when ink is not being ejected. A configuration in which a differential pressure valve is provided as a means for applying back pressure to the ink in the liquid storage tank has been considered. This differential pressure valve is configured to open and close according to the difference in pressure between the upstream and downstream sides of the differential pressure valve, and the back pressure applied to the ink is controlled by opening and closing this differential pressure valve.

[0005] However, this differential pressure valve is disposed in the middle of an ink supply system for supplying ink from a liquid storage tank to the nozzles, which poses a problem of increasing the size of the entire ink supply system.

[0006] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a replenishment type liquid storage tank that can apply sufficient back pressure to the liquid while avoiding the liquid supply system becoming larger, and an image forming apparatus equipped with this replenishment type liquid storage tank. [Means for solving the problem]

[0007] The replenishment type liquid storage tank according to the present disclosure is a liquid storage tank capable of being replenished with liquid, comprising a tank main body into which liquid is replenished, and a back pressure applying member constituted by an absorbent that absorbs liquid and applies back pressure to the liquid in the tank main body, wherein the tank main body has an upper limit indicating portion that indicates the liquid level height of the maximum amount of liquid that can be stored in the tank main body, and at least a portion of the back pressure applying member is located above the upper limit indicating portion.

[0008] The image forming apparatus according to the present disclosure is characterized by including a refill-type liquid storage tank according to the present disclosure.

[0009] According to the present disclosure, at least a part of the back pressure applying member is located above the upper limit indicator. Therefore, the absorbed liquid is unlikely to reach the part of the back pressure applying member located above the upper limit indicator, and therefore a part where no liquid is absorbed can be formed in the back pressure applying member. Therefore, even if the tank body is filled with liquid up to the upper limit indicator, the back pressure applying member can continue to perform the liquid absorption function, and sufficient back pressure can be applied to the liquid. In addition, the back pressure applying member made of an absorber has a much simpler structure than a differential pressure valve. Therefore, the back pressure applying member made of such an absorber can avoid the liquid supply system from becoming larger. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a schematic configuration example of a refill-type liquid storage tank according to the present disclosure. [Diagram 2]FIG. 1 is a diagram illustrating an example of the configuration of an image forming apparatus according to the present disclosure. [Diagram 3] FIG. 13 is a schematic diagram showing a modified example of the back pressure applying member according to the present disclosure. [Figure 4] FIG. 1 is a schematic diagram showing a modification of a refillable liquid storage tank according to the present disclosure; [Diagram 5] FIG. 2 is a schematic diagram showing a modified example of a refillable liquid storage tank according to the present disclosure; [Figure 6] FIG. 3 is a schematic diagram showing a modified example of the refill-type liquid storage tank according to the present disclosure; [Figure 7] FIG. 4 is a schematic diagram showing a modification of the refill-type liquid storage tank according to the present disclosure; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. The ink tank 1 illustrated in FIG. 1 is an example of a refillable liquid tank in a usage position, and includes a back pressure applying member 3 inside a tank body 2 that constitutes the outer shell of the tank. The inside of the tank body 2 is separated into an ink storage section 5 and a back pressure applying member accommodating section 6 by a partition wall 4. The ink storage section 5 is an example of a liquid storage section, and forms a space capable of storing ink inside. The back pressure applying member accommodating section 6 accommodates the back pressure applying member 3 inside. The vertical length of the back pressure applying member accommodating section 6 is longer than the vertical length of the ink storage section 5. As a result, the upper wall section 2a of the tank body 2 is a stepped wall section having a high wall section 2a1 and a low wall section 2a2 that is lower than the high wall section 2a1.

[0012] The partition wall 4 is provided at the boundary between the ink storage section 5 and the back pressure application member accommodating section 6 so as to extend linearly from above to below. The lower end of the partition wall 4 does not reach the lower wall section 2b of the tank main body section 2, thereby forming a gap 4a. Inside the tank main body section 2, the lower part of the ink storage section 5 and the lower part of the back pressure application member accommodating section 6 communicate with each other through the gap 4a formed by the partition wall 4. The gap 4a is provided at least below a protruding section 2L indicating an upper limit indication section UL, which will be described later. In other words, the ink storage section 5 and the back pressure application member accommodating section 6 communicate with each other through the gap 4a provided below a protruding section 2L indicating an upper limit indication section UL. In this case, the partition wall 4 is configured as a wall section that is impermeable to liquids such as ink.

[0013] The ink storage tank 1 also includes an auxiliary absorber 7. The auxiliary absorber 7 is arranged so as to extend into both the ink storage section 5 and the back pressure application member housing section 6 through the gap 4a formed by the partition section 4. The auxiliary absorber 7 is made of a means capable of absorbing ink, such as a sponge, a spongy body, or a bundle of capillaries, and serves to promote the movement of ink from inside the ink storage section 5 to inside the back pressure application member housing section 6.

[0014] The ink storage tank 1 also includes an ink inlet 8. This allows the ink storage tank 1 to be appropriately replenished with ink, which is an example of a liquid, into the inside of the tank body 2 via the ink inlet 8. In other words, the ink storage tank 1 is configured as a replenishment-type ink storage tank that allows ink to be replenished from the outside to the inside. The ink inlet 8 is an example of a liquid inlet.

[0015] The ink inlet 8 is provided in the upper wall 2a of the tank main body 2. In this case, the ink inlet 8 is provided in the bottom wall 2a2 of the upper wall 2a of the tank main body 2, which constitutes the upper wall of the ink storage section 5. The ink inlet 8 penetrates the upper wall 2a of the tank main body 2, in this case the bottom wall 2a2, in the vertical direction, and has a cylindrical shape with its lower end protruding downward from the upper wall 2a of the tank main body 2, that is, into the tank main body 2, more specifically, into the ink storage section 5. The ink inlet 8 has an upper end protruding upward from the upper wall 2a of the tank main body 2. The ink storage tank 1 is also provided with a detachable cap 8a that can seal the ink inlet 8.

[0016] The ink storage tank 1 also has an atmosphere vent 9. In this case, the atmosphere vent 9 is provided in the lower wall portion 2a2 of the upper wall portion 2a of the tank main body 2, similar to the ink inlet 8. The atmosphere vent 9 is an opening for allowing the atmosphere to circulate between the inside and outside of the tank main body 2.

[0017] Further, the ink storage tank 1 is provided with an upper limit indicator UL. The upper limit indicator UL is a line set at a height equivalent to the liquid level of the maximum allowable amount of ink that can be stored in the tank main body 2. In this case, a visible line extending in a straight line in the horizontal direction on the side wall 2c of the tank main body 2, in other words, a physical line structure formed by the protruding portion 2L, is provided at the same height as the upper limit indicator UL. The user can visually recognize that the vertical height of this physical line structure is the height of the upper limit indicator UL. Note that the physical line structure indicating the upper limit indicator UL is not limited to a protruding portion protruding from the side wall 2c, but may be, for example, a recessed portion recessed in the side wall 2c, or a label directly printed on the side wall 2c or a sticker attached to the side wall 2c. Furthermore, the line structure may be any structure, such as a plurality of convex dots or concave dots, as long as it can indicate a height equivalent to the liquid level of the maximum allowable amount of ink that can be stored in the tank main body 2. Furthermore, the upper limit indicator UL is set at a position at least higher than the center of the tank main body 2 in the vertical direction. Moreover, the upper limit indicator UL is set at least at the same position as the bottom end of the ink inlet 8 or at a position lower than the bottom end of the ink inlet 8.

[0018] The ink storage tank 1 also includes an ink outlet 10 for allowing the ink in the tank body 2 to flow out. This allows the ink storage tank 1 to supply ink to the recording head 11 via the ink outlet 10. The ink outlet 10 is provided in the lower wall 2b of the tank body 2. In this case, the ink outlet 10 is provided in a portion of the lower wall 2b of the tank body 2 that constitutes the lower wall of the back pressure application member accommodating portion 6. The recording head 11 includes a plurality of nozzles that eject ink onto an image formation object, such as a sheet. The recording head 11 forms an image on the image formation object using ink supplied from inside the tank body 2.

[0019] Next, a specific example of the configuration of the back pressure applying member 3 will be described. The back pressure applying member 3 is made of an absorbent capable of absorbing liquid, in this case, ink. As the absorbent constituting the back pressure applying member 3, any suitable means capable of absorbing ink, such as a sponge, a spongy body, or a bundle of capillaries, can be used. The back pressure applying member 3 absorbs ink supplied to the inside of the tank main body 2, in this case, ink supplied to the inside of the ink storage section 5 through the ink inlet 8, through the gap 4a. That is, the back pressure applying member 3 absorbs ink from its lower portion, and the absorbed ink permeates the back pressure applying member 3 from the lower side to the upper side.

[0020] At least a part of the back pressure applying member 3, in this case the upper part, is located above the upper limit indicator UL described above. Furthermore, the upper part of the back pressure applying member 3 is located above the lower end of the ink inlet 8. Furthermore, the upper part of the back pressure applying member 3 is located above the upper wall part 2a of the tank main body 2 where the ink inlet 8 is provided, in this case the bottom wall part 2a2. Furthermore, the upper part of the back pressure applying member 3 is located above the upper end of the ink inlet 8.

[0021] The ink storage tank 1 is configured such that, inside the tank main body 2, an ink storage section 5 and a partition wall 4 are interposed between the back pressure application member 3 and the ink inlet 8. Therefore, the ink inlet 8 is provided so as to be in a non-contact state, i.e., not in direct contact with the back pressure application member 3.

[0022] As illustrated in FIG. 2, the ink storage tank 1 according to the present disclosure is provided in an image forming apparatus 100 such as an inkjet printer. In this case, the image forming apparatus 100 is configured as an on-carriage type apparatus in which the ink storage tank 1 is provided on a carriage 101 that moves back and forth during image formation on an image formation object. The image forming apparatus 100 may be an off-carriage type apparatus in which the ink storage tank 1 is provided on a portion other than the carriage. The image forming apparatus 100 may also be an apparatus having a linear image forming unit that does not move back and forth. The image forming apparatus 100 may also be an apparatus in which the ink storage tank 1 is detachably provided, or may also be an apparatus in which the ink storage tank 1 is non-detachably provided. The image forming apparatus 100 is not limited to an apparatus that forms an image using ink, but may also be an apparatus that forms an image using a liquid other than ink.

[0023] According to the ink storage tank 1 described above, at least a part of the back pressure applying member 3, in this case the upper part, is located above the upper limit indication part UL. Therefore, the absorbed ink is unlikely to reach the part of the back pressure applying member 3 located above the upper limit indication part UL, and therefore the back pressure applying member 3 is likely to have a part where the ink is not absorbed. Therefore, even if the ink is supplied to the tank main body 2 up to the upper limit indication part UL, the back pressure applying member 3 can continue to perform the ink absorption function, and a sufficient back pressure can be stably, in other words, reliably applied to the ink. In addition, the back pressure applying member 3 made of an absorber has a significantly simpler structure than the back pressure applying means using a conventional differential pressure valve. Therefore, according to the back pressure applying member 3 made of such an absorber, it is possible to avoid an increase in size of the ink supply system from the ink storage tank 1 to the nozzles of the recording head 11.

[0024] Also, in the past, a configuration has been known in which back pressure is generated in ink by the height difference between the ink storage tank and the image forming unit, that is, a configuration in which back pressure is applied by the so-called head difference. However, this configuration using the head difference also requires a certain level of height difference between the ink storage tank and the image forming unit, so the ink supply system tends to become large. The ink storage tank 1 according to the present disclosure does not use such a back pressure applying configuration using the head difference, but instead uses a simple back pressure applying member 3 made of an absorber. Therefore, the ink storage tank 1 according to the present disclosure is based on a technology that is clearly different from the conventional back pressure applying configuration using the head difference.

[0025] Furthermore, in the ink storage tank 1, the upper part of the back pressure applying member 3 is located above the lower end of the ink inlet 8, which is located even higher than the upper limit indicator UL. Therefore, even if ink is replenished into the tank main body 2 beyond the upper limit indicator UL, there is an increased likelihood that there will be portions of the back pressure applying member 3 where ink is not absorbed, and back pressure can be applied to the ink more stably, in other words, more reliably.

[0026] Furthermore, according to the ink storage tank 1, the upper part of the back pressure applying member 3 is located on the upper wall 2a of the tank main body 2, which is further above the lower end of the ink inlet 8, in this case, above the bottom wall 2a2 where the ink inlet 8 is provided. Therefore, even if ink is replenished into the tank main body 2 beyond the upper limit indication UL, there is an increased likelihood that there will be portions of the back pressure applying member 3 where ink is not absorbed, and back pressure can be applied to the ink more stably, in other words, more reliably.

[0027] Furthermore, in the ink storage tank 1, the upper portion of the back pressure applying member 3 is located above the upper end of the ink inlet 8, which is located even higher than the bottom wall portion 2a2 in which the ink inlet 8 is provided. Therefore, even if ink is supplied to the tank main body 2 beyond the upper limit indication portion UL, there is an increased likelihood that there will be portions of the back pressure applying member 3 where ink is not absorbed, and back pressure can be applied to the ink more stably, in other words, more reliably.

[0028] Moreover, in the ink storage tank 1, the inside of the tank main body 2, to which ink is supplied, is divided by the partition wall 4 into an ink storage section 5 and a back pressure application member accommodating section 6. With this configuration, the partition wall 4 can prevent air from coming into direct contact with the back pressure application member 3 in the back pressure application member accommodating section 6 from the ink storage section 5 side. Furthermore, in the tank main body 2, the ink storage section 5 and the back pressure application member accommodating section 6 are in communication with each other through a gap 4a formed by the partition wall 4. Therefore, even with the partition wall 4 provided, the movement of ink from the ink storage section 5 to the back pressure application member accommodating section 6 can proceed smoothly without being impeded.

[0029] Furthermore, according to the ink storage tank 1, the ink inlet 8 is provided in the upper wall 2a of the wall that constitutes the outer shell of the tank main body 2. With this configuration, ink can be refilled into the tank main body 2 from above the ink storage tank 1, making the refilling operation easy. Note that the ink storage tank 1 may also be configured such that the ink inlet 8 is provided in the side wall 2c of the wall that constitutes the outer shell of the ink main body 2. In this case, it is preferable that the ink inlet 8 is configured to be inclined so that its opening faces upward.

[0030] The present disclosure is not limited to the above-described embodiment, and various modifications and extensions are possible without departing from the spirit and scope of the present disclosure.

[0031] 3, various shapes can be applied to the shape of the upper part of the back pressure applying member 3. In other words, it is sufficient that at least a part of the back pressure applying member 3 is located above the upper limit indicator UL, and therefore, as long as a part of the back pressure applying member 3 is located above the upper limit indicator UL, various shapes can be adopted, for example, as shown in patterns A, B, C, etc.

[0032] 4, the ink inlet 8 may be an inlet that does not protrude downward from the upper wall 2a of the tank body 2. In this case, it is preferable that the upper part of the back pressure applying member 3 is configured to be located above the lower end of the ink inlet 8.

[0033] 5, the cap 8a may be an insert-type cap in which the main body 8a1 is inserted into the ink inlet 8. In this case, the upper part of the back pressure applying member 3 may be configured to be located above the lower end of the main body 8a1 of the cap 8a.

[0034] As shown in FIG. 6, the atmosphere communication port 9 may be provided in both the high wall portion 2a1 and the low wall portion 2a2 of the upper wall portion 2a of the tank main body 2, or in either one of them.

[0035] 7, the ink storage tank 1 may not include the partition wall 4. In this case, the back pressure applying member 3 may be provided in the portion where the ink storage section 5 was formed in the above-mentioned embodiment. In this case, the upper portion of the back pressure applying member 3 is stepped, having a high portion 3a1 and a low portion 3a2 lower than the high portion 3a1. Therefore, the upper limit indication portion UL may be provided at least above the low portion 3a2 of the back pressure applying member 3. In this case, the ink inlet 8 may be provided so as to be in a non-contact state, i.e., not in contact with the back pressure applying member 3. In this case, the ink storage tank 1 may also not include the auxiliary absorber 7. In this case, the air communication port 9 may be provided in the high wall portion 2a1 constituting the back pressure applying member accommodating section 6 of the upper wall portion 2a of the tank main body 2.

[0036] In addition, in a configuration in which the ink storage tank 1 includes the partition wall 4, it is preferable to provide the atmosphere communication port 9 in the low wall portion 2a2, not in the high wall portion 2a1. In a configuration in which the ink storage tank 1 does not include the partition wall 4, it is preferable to provide the atmosphere communication port 9 in the high wall portion 2a1, not in the low wall portion 2a2. In a configuration in which the ink storage tank 1 includes the partition wall 4, the most preferable position for the atmosphere communication port 9 is to provide it in the low wall portion 2a2.

[0037] The back pressure applying member 3 may be configured to include a plurality of back pressure applying blocks. In this case, by making the liquid absorption performance of the plurality of back pressure applying blocks different, the liquid absorption performance of the back pressure applying member 3 as a whole, and therefore the back pressure applying performance, can be easily adjusted. In this case, it is preferable to make the back pressure applying blocks arranged at the lower side have a higher liquid absorption performance and the back pressure applying blocks arranged at the upper side have a lower liquid absorption performance. This makes it easier to form a portion at the upper part of the back pressure applying member 3 where liquid is less easily absorbed, and prevents the liquid from penetrating the entire back pressure applying member 3, in other words, prevents the back pressure applying function of the back pressure applying member 3 from being reduced or lost. [Explanation of symbols]

[0038] 1: ink storage tank (supply type liquid storage tank), 2: tank main body, 3: back pressure application member, 4: partition wall, 5: ink storage section (liquid storage section), 6: back pressure application member housing section, 8: ink inlet (liquid inlet), 100: image forming apparatus, UL: upper limit indicator

Claims

1. A refillable liquid storage tank capable of refilling liquid therein, a tank body portion into which liquid is replenished; a back pressure applying member configured with an absorbent that absorbs liquid and applies back pressure to the liquid in the tank main body; Equipped with The inside of the tank main body is separated into a liquid storage section in which liquid is stored and a back pressure application member accommodating section in which the back pressure application member is accommodated, an upper limit indicator that indicates a liquid level of a maximum amount of liquid that can be stored in the tank main body is set in the tank main body; 13. A replenishment type liquid storage tank, wherein at least a portion of the back pressure applying member is located above an upper wall of the liquid storage portion and above the upper limit indicating portion.

2. 2. The refillable liquid storage tank according to claim 1, wherein the upper limit indicator is structured to indicate a height equivalent to the liquid level.

3. 3. The refillable liquid storage tank according to claim 2, wherein the upper limit indicator has a linear structure.

4. 4. A refillable liquid storage tank as described in any one of claims 1 to 3, characterized in that the tank main body is separated into the liquid storage section and the back pressure application member accommodating section, and further includes an isolation wall that connects the liquid storage section and the back pressure application member accommodating section below the upper limit indication section.

5. the tank body includes a liquid inlet on an upper wall of the liquid storage portion, 5. The replenishment type liquid storage tank according to claim 1, wherein at least a portion of the back pressure applying member is located above an upper end of the liquid inlet.

6. 6. The refillable liquid storage tank according to claim 5, further comprising a detachable cap capable of sealing the liquid inlet.

7. A refillable liquid storage tank according to any one of claims 1 to 6; a recording head that forms an image on an image forming object using the liquid supplied from the replenishment type liquid storage tank; An image forming apparatus comprising:

Images